Search results for: waste materials

Authors: Aya Tanaka, Mariko Era, Manami Masuda, Yui Okuno, Takayoshi Kawahara, Takahide Kanyama, Hiroshi Morita

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Objectives— Fungi and bacteria are present in a wide range of natural environments. They are breed in the foods such as vegetables and fruit, causing corruption and deterioration of these foods in some cases. Furthermore, some species of fungi and bacteria are known to cause food intoxication or allergic reactions in some individuals. To prevent fungal and bacterial contamination, various fungicides and bactericidal have been developed that inhibit fungal and bacterial growth. Fungicides and bactericides must show high antifungal and antibacterial activity, sustainable activity, and a high degree of safety. Therefore, we focused on the fatty acid salt which is the main component of soap. We focused on especially C10K and C12K. This study aimed to find the effectiveness of the fatty acid salt as antimicrobial agents for food safety. Materials and Methods— Cladosporium cladosporioides NBRC 30314, Penicillium pinophilum NBRC 6345, Aspergillus oryzae (Akita Konno store), Rhizopus oryzae NBRC 4716, Fusarium oxysporum NBRC 31631, Escherichia coli NBRC 3972, Bacillus subtilis NBRC 3335, Staphylococcus aureus NBRC 12732, Pseudomonas aenuginosa NBRC 13275 and Serratia marcescens NBRC 102204 were chosen as tested fungi and bacteria. Hartmannella vermiformis NBRC 50599 and Acanthamoeba castellanii NBRC 30010 were chosen as tested amoeba. Nine fatty acid salts including potassium caprate (C10K) and laurate (C12K) at 350 mM and pH 10.5 were used as antifungal activity. The spore suspension of each fungus (3.0×10⁴ spores/mL) or the bacterial suspension (3.0×10⁵ or 3.0×10⁶ or 3.0×10⁷ CFU/mL) was mixed with each of the fatty acid salts (final concentration of 175 mM). Samples were counted at 0, 10, 60, and 180 min by plating (100 µL) on potato dextrose agar or nutrient agar. Fungal and bacterial colonies were counted after incubation for 1 or 2 days at 30 °C. Results— C10K was antifungal activity of 4 log-unit incubated time for 10 min against fungi other than A. oryzae. C12K was antifungal activity of 4 log-unit incubated time for 10 min against fungi other than P. pinophilum and A. oryzae. C10K and C12K did not show high anti-yeast activity. C10K was antibacterial activity of 6 or 7 log-unit incubated time for 10 min against bacteria other than B. subtilis. C12K was antibacterial activity of 5 to 7 log-unit incubated time for 10 min against bacteria other than S. marcescens. C12K was anti-amoeba activity of 4 log-unit incubated time for 10 min against H. vermiformis. These results suggest C10K and C12K have potential in the field of food safety.

Keywords: food safety, microbes, antimicrobial, fatty acid salts

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Authors: Sofia Lazareva, Artem Smolentsev

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Fluorescent photochromic materials collect strong interest due to their possible application in organic photonics such as optical logic systems, optical memory, visualizing sensors, as well as characterization of polymers and biological systems. In photochromic fluorescence switching systems the emission of fluorophore is modulated between ‘on’ and ‘off’ via the photoisomerization of photochromic moieties resulting in effective resonance energy transfer (FRET). In current work, we have studied both photochromic and fluorescent properties of several diarylethenes. It was found that coloured forms of these compounds are not fluorescent because of the efficient intramolecular energy transfer. Spectral and photochromic parameters of investigated substances have been measured in five solvents having different polarity. Quantum yields of photochromic transformation A↔B ΦA→B and ΦB→A as well as B isomer extinction coefficients were determined by kinetic method. It was found that the photocyclization reaction quantum yield of all compounds decreases with the increase of solvent polarity. In addition, the solvent polarity is revealed to affect fluorescence significantly. Increasing of the solvent dielectric constant was found to result in a strong shift of emission band position from 450 nm (nhexane) to 550 nm (DMSO and ethanol) for all three compounds. Moreover, the emission intensive in polar solvents becomes weak and hardly detectable in n-hexane. The only one exception in the described dependence is abnormally low fluorescence quantum yield in ethanol presumably caused by the loss of electron-donating properties of nitrogen atom due to the protonation. An effect of the protonation was also confirmed by the addition of concentrated HCl in solution resulting in a complete disappearance of the fluorescent band. Excited state dynamics were investigated by ultrafast optical spectroscopy methods. Kinetic curves of excited states absorption and fluorescence decays were measured. Lifetimes of transient states were calculated from the data measured. The mechanism of ring opening reaction was found to be polarity dependent. Comparative analysis of kinetics measured in acetonitrile and hexane reveals differences in relaxation dynamics after the laser pulse. The most important fact is the presence of two decay processes in acetonitrile, whereas only one is present in hexane. This fact supports an assumption made on the basis of steady-state preliminary experiments that in polar solvents occur stabilization of TICT state. Thus, results achieved prove the hypothesis of two channel mechanism of energy relaxation of compounds studied.

Keywords: diarylethenes, fluorescence switching, FRET, photochromism, TICT state

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Authors: G. V. Manzane, S. J. Modise

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Uterine fibroids, also known as leiomyomas or myomas, are non-cancerous growths that develop in the muscular wall of the uterus during the reproductive years. The cause of uterine fibroids includes hormonal, genetic, growth factors, and extracellular matrix factors. Common symptoms of uterine fibroids include heavy and prolonged menstrual bleeding which can lead to a high risk of anemia, lower abdominal pains, pelvic pressure, infertility, and pregnancy loss. The growth of this tumor is a concern because of its negative impact on women’s health and the increase in their economic burden. Traditional medicinal plants have long been used in Africa for their potential therapeutic effects against various ailments. In this study, we aimed to identify and characterize bioactive compounds from selected African medicinal plants with potential anti-fibrotic properties using Fourier-transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GCMS) analysis. Two medicinal plant species known for their traditional use in fibrosis-related conditions were selected for investigation. Aqueous extracts were prepared from the plant materials, and FTIR analysis was conducted to determine the functional groups present in the extracts. GCMS analysis was performed to identify the chemical constituents of the extracts. The FTIR analysis revealed the presence of various functional groups, such as phenols, flavonoids, terpenoids, and alkaloids, known for their potential therapeutic activities. These functional groups are associated with antioxidant, anti-inflammatory, and anti-fibrotic properties. The GCMS analysis identified several bioactive compounds, including flavonoids, alkaloids, terpenoids, and phenolic compounds, which are known for their pharmacological activities. The discovery of bioactive compounds in African medicinal plants that exhibit anti-fibrotic effects, opens up promising avenues for further research and development of potential treatments for fibrosis. This suggests the potential of these plants as a valuable source of novel therapeutic agents for treating fibrosis-related conditions. In conclusion, our study identified and characterized bioactive compounds from selected African medicinal plants using FTIR and GCMS analysis. The presence of compounds with known antifibrotic properties suggests that these plants hold promise as a potential source of natural products for the development of novel anti-fibrotic therapies.

Keywords: uterine fibroids, african medicinal plants, bioactive compounds, identify and characterized

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Authors: E. Zafeiraki, P. Nisianakis, K. Machera

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Cannabis plant contains 113 cannabinoids and it is commonly known for its psychoactive substance tetrahydrocannabinol or as a source of narcotic substances. The recent years’ cannabis cultivation also increases due to its wide use both for medical and industrial purposes as well as for uses as para-pharmaceuticals, cosmetics and food commodities. Depending on the final product, different parts of the plant are utilized, with the leaves and bud (seeds) being the most frequently used. Cannabis can accumulate various contaminants, including heavy metals, both from the soil and the water in which the plant grows. More specifically, metals may occur naturally in the soil and water, or they can enter into the environment through fertilizers, pesticides and fungicides that are commonly applied to crops. The high probability of metals accumulation in cannabis, combined with the latter growing use, raise concerns about the potential health effects in humans and consequently lead to the need for the implementation of safety measures for cannabis products, such as guidelines for regulating contaminants, including metals, and especially the ones characterized by high toxicity in cannabis. Acknowledging the above, the aim of the current study was first to investigate metals contamination in cannabis samples collected from Greece, and secondly to examine potential differences in metals accumulation among the different parts of the plant. To our best knowledge, this is the first study presenting information on elements in cannabis cultivated in Greece, and also on the distribution pattern of the former in the plant body. To this end, the leaves and the seeds of all the samples were initially separated and dried and then digested with Nitric acid (HNO₃) and Hydrochloric acid (HCl). For the analysis of these samples, an Inductive Coupled Plasma-Mass Spectrometry (ICP-MS) method was developed, able to quantify 28 elements. Internal standards were added at a constant rate and concentration to all calibration standards and unknown samples, while two certified reference materials were analyzed in every batch to ensure the accuracy of the measurements. The repeatability of the method and the background contamination were controlled by the analysis of quality control (QC) standards and blank samples in every sequence, respectively. According to the results, essential metals, such as Ca, Zn and Mg, were detected at high levels. On the contrary, the concentration of high toxicity metals, like As (average: 0.10ppm), Pb (average: 0.36ppm), Cd (average: 0.04ppm), and Hg (average: 0.012ppm) were very low in all the samples, indicating that no harmful effects on human health can be caused by the analyzed samples. Moreover, it appears that the pattern of contamination of metals is very similar in all the analyzed samples, which could be attributed to the same origin of the analyzed cannabis, i.e., the common soil composition, use of fertilizers, pesticides, etc. Finally, as far as the distribution pattern between the different parts of the plant is concerned, it was revealed that leaves present a higher concentration in comparison to seeds for all metals examined.

Keywords: cannabis, heavy metals, ICP-MS, leaves and seeds, elements

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Authors: Neha Sahu, Awantika Singh, Brijesh Kumar, K. R. Arya

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Taraxacum officinale Weber or dandelion (Asteraceae) is an important Indian traditional herb used to treat liver detoxification, digestive problems, spleen, hepatic and kidney disorders, etc. The plant is well known to possess important phenolic and flavonoids to serve as a potential source of antioxidative and chemoprotective agents. Biosynthesis of bioactive compounds through in vitro cultures is a requisite for natural resource conservation and to provide an alternative source for pharmaceutical applications. Thus an efficient and reproducible protocol was developed for in vitro biosynthesis of bioactive antioxidative compounds from leaf derived callus and in vitro regenerated cultures of Taraxacum officinale using MS media fortified with various combinations of auxins and cytokinins. MS media containing 0.25 mg/l 2, 4-D (2, 4-Dichloro phenoxyacetic acid) with 0.05 mg/l 2-iP [N6-(2-Isopentenyl adenine)] was found as an effective combination for the establishment of callus with 92 % callus induction frequency. Moreover, 2.5 mg/l NAA (α-Naphthalene acetic acid) with 0.5 mg/l BAP (6-Benzyl aminopurine) and 1.5 mg/l NAA showed the optimal response for in vitro plant regeneration with 80 % regeneration frequency and rooting respectively. In vitro regenerated plantlets were further transferred to soil and acclimatized. Quantitative variability of accumulated bioactive compounds in cultures (in vitro callus, plantlets and acclimatized) were determined through UPLC-MS/MS (ultra-performance liquid chromatography-triple quadrupole-linear ion trap mass spectrometry) and compared with wild plants. The phytochemical determination of in vitro and wild grown samples showed the accumulation of 6 compounds. In in vitro callus cultures and regenerated plantlets, two major antioxidative compounds i.e. chlorogenic acid (14950.0 µg/g and 4086.67 µg/g) and umbelliferone (10400.00 µg/g and 2541.67 µg/g) were found respectively. Scopoletin was found to be highest in vitro regenerated plants (83.11 µg/g) as compared to wild plants (52.75 µg/g). Notably, scopoletin is not detected in callus and acclimatized plants, but quinic acid (6433.33 µg/g) and protocatechuic acid (92.33 µg/g) were accumulated at the highest level in acclimatized plants as compared to other samples. Wild grown plants contained highest content (948.33 µg/g) of flavonoid glycoside i.e. luteolin-7-O-glucoside. Our data suggests that in vitro callus and regenerated plants biosynthesized higher content of antioxidative compounds in controlled conditions when compared to wild grown plants. These standardized cultural conditions may be explored as a sustainable source of plant materials for enhanced production and adequate supply of oxidative polyphenols.

Keywords: anti-oxidative compounds, in vitro cultures, Taraxacum officinale, UPLC-MS/MS

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Authors: Reyhan Özdoğan, Mithat Çelebi, Özgür Ceylan, Mehmet Arif Kaya

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Super absorbent polymers (SAPs) are defined as materials that can absorb huge amount of water or aqueous solution in comparison to their own mass and retain in their lightly cross-linked structure. SAPs were produced from water soluble monomers via polymerization subsequently controlled crosslinking. SAPs are generally used for water absorbing applications such as baby diapers, patient or elder pads and other hygienic product industries. Crosslinking density (CD) of SAP structure is an essential factor for water absortion capacity (WAC). Low internal CD leads to high WAC values and vice versa. However, SAPs have low CD and high swelling capacities and tend to disintegrate when pressure is applied upon them, so SAPs under load cannot absorb liquids effectively. In order to prevent this undesired situation and to obtain suitable SAP structures having high swelling capacity and ability to work under load, surface crosslinking can be the answer. In industry, these superabsorbent gels are mostly produced via solution polymerization and then they need to be dried, grinded, sized, post polymerized and finally surface croslinked (involves spraying of a crosslinking solution onto dried and grinded SAP particles, and then curing by heat). It can easily be seen that these steps are time consuming and should be handled carefully for the desired final product. If we could synthesize desired final SAPs using less processes it will help reducing time and production costs which are very important for any industries. In this study, synthesis of SAPs were achieved successfully by inverse suspension (Pickering type) polymerization and subsequently in-situ surface cross-linking via using proper surfactants in high boiling point solvents. Our one-pot synthesis of surface cross-linked SAPs invovles only one-step for preparation, thus it can be said that this technique exhibits more preferable characteristic for the industry in comparison to conventional methods due to its one-step easy process. Effects of different surface crosslinking agents onto properties of poly(acrylic acid-co-sodium acrylate) based SAPs are investigated. Surface crosslink degrees are evaluated by swelling under load (SUL) test. It was determined water absorption capacities of obtained SAPs decrease with the increasing surface crosslink density while their mechanic properties are improved.

Keywords: inverse suspension polymerization, polyacrylic acid, super absorbent polymers (SAPs), surface crosslinking, sodium polyacrylate

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Authors: Yogita Patil-Sen

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Superparamagnetic Iron Oxide Nanoparticles (SPIONs) have become increasingly important materials for separation of specific bio-molecules, drug delivery vehicle, contrast agent for MRI and magnetic hyperthermia for cancer therapy. Hyperthermia is emerging as an alternative cancer treatment to the conventional radio- and chemo-therapy, which have harmful side effects. When subjected to an alternating magnetic field, the magnetic energy of SPIONs is converted into thermal energy due to movement of particles. The ability of SPIONs to generate heat and potentially kill cancerous cells, which are more susceptible than the normal cells to temperatures higher than 41 °C forms the basis of hyerpthermia treatement. The amount of heat generated depends upon the magnetic properties of SPIONs which in turn is affected by their properties such as size and shape. One of the main problems associated with SPIONs is particle aggregation which limits their employability in in vivo drug delivery applications and hyperthermia cancer treatments. Coating the iron oxide core with thermally responsive lipid based nanostructures tend to overcome the issue of aggregation as well as improve biocompatibility and can enhance drug loading efficiency. Herein we report suitability of SPIONs and silica coated core-shell SPIONs, which are further, coated with various lipids for drug delivery and magnetic hyperthermia applications. The synthesis of nanoparticles is carried out using the established methods reported in the literature with some modifications. The nanoparticles are characterised using Infrared spectroscopy (IR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Vibrating Sample Magnetometer (VSM). The heating ability of nanoparticles is tested under alternating magnetic field. The efficacy of the nanoparticles as drug carrier is also investigated. The loading of an anticancer drug, Doxorubicin at 18 °C is measured up to 48 hours using UV-visible spectrophotometer. The drug release profile is obtained under thermal incubation condition at 37 °C and compared with that under the influence of alternating magnetic field. The results suggest that the nanoparticles exhibit superparamagnetic behaviour, although coating reduces the magnetic properties of the particles. Both the uncoated and coated particles show good heating ability, again it is observed that coating decreases the heating behaviour of the particles. However, coated particles show higher drug loading efficiency than the uncoated particles and the drug release is much more controlled under the alternating magnetic field. Thus, the results demonstrate that lipid coated SPIONs exhibit potential as drug delivery vehicles for magnetic hyperthermia based cancer therapy.

Keywords: drug delivery, hyperthermia, lipids, superparamagnetic iron oxide nanoparticles (SPIONS)

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Authors: Shashi Bala, Neha A. Chugh, Subhash C. Bansal, Mohal L. Garg, Ashwani Koul

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Purpose: The present study was designed to evaluate the radioprotective efficacy of Aloe vera from whole body X-ray exposure in rodents. Materials and Methods: For this purpose, after on week’s acclimatization, male balb/c mice procured from Central Animal House, Panjab University, Chandigarh (India), were divided into four groups: Group I mice served as control. Group II mice were orally administrated Aloe vera pulp extract (50 mg/ kg body weight) on alternate days for 30 days. Group III mice were subjected to whole body X-ray irradiation to cumulative dose of 2Gy (0.258Gy twice a day for four days in the last week). Group IV animals were pretreated with Aloe vera pulp extract on alternate days as in Group II and in the last week of the study, they were exposed to X-ray as in Group III. Results: Spleen of X-ray irradiated mice showed histopathological alterations accompanied with enhanced activity of lactate dehydrogenase (LDH) in serum. Elevated levels of reactive oxygen species (ROS), lipid peroxidation (LPO), enhanced activities in Glutathione based enzymes such as Glutathione peroxidase (GSH-Px), Glutathione reductase (GR), Catalase (CAT), Superoxide dismutase (SOD) associated with depletion in reduced Glutathione (GSH) concentration were observed after X-ray exposure in blood plasma and spleen.. Pro-inflammatory cytokines like tumor necrosis factors (TNF-α) and Inteleukin-6 (IL-6) levels were also found to be enhanced in serum of irradiated mice. Irradiation-induced significant elevation in Total leucocyte counts (TLC), neutrophil counts and decline in platelet counts, associated with unaltered levels of red blood cell counts (RBC’s) and haemoglobin (Hb) in various treatment groups. Clastogenic damage and apoptosis was also found to be increase in splenic tissue of X-ray exposed mice as assessed by micronucleus and TUNEL assay. However, X-ray irradiated animals administered with Aloe vera revealed significant improvement in levels of ROS/ LPO, LDH activity, and antioxidant mechanism. Aloe vera pretreated animals exhibited less severe damage, and early recovery in micronucleated cells, hematological parameters, apoptotic cells and inflammatory markers as compared to X-ray exposed mice. Conclusion: These results indicate that the radioprotective potential of Aloe vera against X-ray induced damage. This may be due to its free radical scavenging, antioxidant, anti-apoptotic and anti-inflammatory properties.

Keywords: aloe vera, antioxidant defense system, lactate dehydrogenase (LDH), micronucleus assay, x-ray

Procedia PDF Downloads 192

Authors: Abdurahman Anwar Shfa

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Addis Ababa is among the fastest-growing urban areas in the country. There are many new constructions of public and private condominiums and large new low rising residential buildings for residents. But the wide range of heaving problems of expansive soil in the city become a major difficulty for the construction sector, especially in low rising buildings, by causing different problems such as distortion and cracking of floor slabs, cracks in grade beams, and walls, jammed or misaligned Doors and Windows; failure of blocks supporting grade beams. Hence an attractive and economical design solution may be required for such type of problem. Therefore, this research works to publicize a recent innovation called the Granular Anchor Pile system for the reduction of the heave effect of expansive soil. This research is written for the objective of numerical investigation of the behavior of Granular Anchor Pile under the heave using Finite element analysis PLAXIS 3D program by means of studying the effect of different parameters like length of the pile, diameter of pile, and pile group by applying prescribed displacement of 10% of pile diameter at the center of granular pile anchor. An additional objective is examining the suitability of Granular Anchor Pile as an alternative solution for heave problems in expansive soils mostly for low rising buildings found in Addis Ababa City, especially in Bole Sub-City, by considering different factors such as the local availability of construction materials, economy for the construction, installation process condition, environmental benefit, time consumption and performance of the pile. Accordingly, the performance of the pile improves when the length of the pile increases. This is due to an increase in the self-weight of the pile and friction mobilized between the pile and soil interface. Additionally, the uplift capacity of the pile decreases when increasing the pile diameter and spacing between the piles in the group due to a reduction in the number of piles in the group. But, few cases show that the uplift capacity of the pile increases with increasing the pile diameter for a constant number of piles in the group and increasing the spacing between the pile and in the case of single pile capacity. This is due to the increment of piles' self-weight and surface area of the pile group and also the decrement of stress overlap in the soil caused by piles respectively. According to the suitability analysis, it is observed that Granular Anchor Pile is sensible or practical to apply for the actual problem of Expansive soil in a low rising building constructed in the country because of its convenience for all considerations.

Keywords: expansive soil, granular anchor pile, PLAXIS, suitability analysis

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Authors: Tsega Asresa, Getahun Tigistu, Melaku Bayih

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Computer vision is a subfield of artificial intelligence that allows computers and systems to extract meaning from digital images and video. It is used in a wide range of fields of study, including self-driving cars, video surveillance, medical diagnosis, manufacturing, law, agriculture, quality control, health care, facial recognition, and military applications. Aromatic medicinal plants are botanical raw materials used in cosmetics, medicines, health foods, essential oils, decoration, cleaning, and other natural health products for therapeutic and Aromatic culinary purposes. These plants and their products not only serve as a valuable source of income for farmers and entrepreneurs but also going to export for valuable foreign currency exchange. In Ethiopia, there is a lack of technologies for the classification and identification of Aromatic medicinal plant parts and disease type cured by aromatic medicinal plants. Farmers, industry personnel, academicians, and pharmacists find it difficult to identify plant parts and disease types cured by plants before ingredient extraction in the laboratory. Manual plant identification is a time-consuming, labor-intensive, and lengthy process. To alleviate these challenges, few studies have been conducted in the area to address these issues. One way to overcome these problems is to develop a deep learning model for efficient identification of Aromatic medicinal plant parts with their corresponding disease type. The objective of the proposed study is to identify the aromatic medicinal plant parts and their disease type classification using computer vision technology. Therefore, this research initiated a model for the classification of aromatic medicinal plant parts and their disease type by exploring computer vision technology. Morphological characteristics are still the most important tools for the identification of plants. Leaves are the most widely used parts of plants besides roots, flowers, fruits, and latex. For this study, the researcher used RGB leaf images with a size of 128x128 x3. In this study, the researchers trained five cutting-edge models: convolutional neural network, Inception V3, Residual Neural Network, Mobile Network, and Visual Geometry Group. Those models were chosen after a comprehensive review of the best-performing models. The 80/20 percentage split is used to evaluate the model, and classification metrics are used to compare models. The pre-trained Inception V3 model outperforms well, with training and validation accuracy of 99.8% and 98.7%, respectively.

Keywords: aromatic medicinal plant, computer vision, convolutional neural network, deep learning, plant classification, residual neural network

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Authors: Ahmad Seiar Yasser

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Sediment is an important habitat for organisms and act as a store house for nutrients in aquatic ecosystems. Hydrogen sulfide is produced by microorganisms in the water columns and sediments, which is highly toxic and fatal to benthic organisms. However, the irons have the capacity to regulate the formation of sulfide by poising the redox sequence and to form insoluble iron sulfide and pyrite compounds. Therefore, we conducted two experiments aimed to evaluate the remediation efficiency of iron application to organically enrich and improve sediments environment. Experiments carried out in the laboratory using intact sediment cores taken from Mikawa Bay, Japan at every month from June to September 2017 and October 2018. In Experiment 1, after cores were collected, the iron powder or iron hydroxide were applied to the surface sediment with 5 g/ m2 or 5.6 g/ m2, respectively. In Experiment 2, we experimentally investigated the removal of hydrogen sulfide using (2mm or less and 2 to 5mm) of the steelmaking slag. Experiments are conducted both in the laboratory with the same boundary conditions. The overlying water were replaced with deoxygenated filtered seawater, and cores were sealed a top cap to keep anoxic condition with a stirrer to circulate the overlying water gently. The incubation experiments have been set in three treatments included the control, and each treatment replicated and were conducted with the same temperature of the in-situ conditions. Water samples were collected to measure the dissolved sulfide concentrations in the overlying water at appropriate time intervals by the methylene blue method. Sediment quality was also analyzed after the completion of the experiment. After the 21 days incubation, experimental results using iron powder and ferric hydroxide revealed that application of these iron containing materials significantly reduced sulfide release flux from the sediment into the overlying water. The average dissolved sulfides concentration in the overlying water of the treatment group was significantly decrease (p = .0001). While no significant difference was observed between the control group after 21 day incubation. Therefore, the application of iron to the sediment is a promising method to remediate contaminated sediments in a eutrophic water body, although ferric hydroxide has better hydrogen sulfide removal effects. Experiments using the steelmaking slag also clarified the fact that capping with (2mm or less and 2 to 5mm) of slag steelmaking is an effective technique for remediation of bottom sediments enriched organic containing hydrogen sulfide because it leads to the induction of chemical reaction between Fe and sulfides occur in sediments which did not occur in conditions naturally. Although (2mm or less) of slag steelmaking has better hydrogen sulfide removal effects. Because of economic reasons, the application of steelmaking slag to the sediment is a promising method to remediate contaminated sediments in the eutrophic water body.

Keywords: sedimentary, H2S, iron, iron hydroxide

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Authors: Ismaila Haruna

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The global downfall in fossil energy prices and dwindling oil reserves in Nigeria has ignited interest in the search for alternative sources of foreign income for the country. Solid minerals, particularly Uranium and other base metals like Lead and Zinc have been considered as potentially good options. Several occurrences of this mineral have been discovered in both the sedimentary and granitic rocks of the Hawal and Adamawa Massifs as well as in the adjoining Benue Trough in northeastern Nigeria. However, the paucity of geochemical data and consequent poor petrogenetic knowledge of the granitoids in this region has made exploration works difficult. Song, a small area within the Hawal Massif, was mapped and the collected samples chemically determined in Activation Laboratory, Canada through fusion dissolution technique of Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Field mapping results show that the area is underlain by Granites, diorites with pockets of gneisses and pegmatites and that these rocks consists of microcline, quartz, plagioclase, biotite, hornblende, pyroxene and accessory apatite, zircon, sphene, magnetite and opaques in various proportions. Geochemical data show continous compositional variation from diorite to granites within silica range of 52.69 to 76.04 wt %. Plot of the data on various Harker variation diagrams show distinct evolutionary trends from diorites to granites indicated by decreasing CaO, Fe2O3, MnO, MgO, Ti2O, and increasing K2O with increasing silica. This pattern is reflected in trace elements data which, in general, decrease from diorite to the granites with rising Rb and K. Tectonic, triangular and other diagrams, indicate high-K calc-alkaline trends, syn-collisional granite signatures, I-type characteristics, with CNK/A of less than 1.1 (minimum of 0.58 and maximum of 0.94) and strong potassic character (K2O/Na2O˃1). However, only the granites are slightly peraluminous containing high silica percentage (68.46 to 76.04), K2O (2.71 to 6.16 wt %) with low CaO (1.88 on the average). Chondrite normalised rare earth elements trends indicate strongly fractionated REEs and enriched LREEs with slightly increasing negative Eu anomaly from the diorite to the granite. On the basis of field and geochemical data, the granitoids are interpreted to be high-K calc-alkaline, I-type, formed as a result of hybridization between mantle-derived magma and continental source materials (probably older meta-sediments) in a syn-collisional tectonic setting.

Keywords: geochemistry, granite, Hawal Massif, Nigeria, petrogenesis, song

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Authors: John Hardy

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Over the last decade, the world has witnessed an unprecedented rise in the quality and availability of violent extremist propaganda. This phenomenon has been fueled primarily by three interrelated trends: rapid adoption of online content mediums by creators of violent extremist propaganda, increasing sophistication of violent extremist content production, and greater coordination of content and action across violent extremist organizations. In particular, the self-styled ‘Islamic State’ attracted widespread attention from its supporters and detractors alike by mixing shocking video and imagery content in with substantive ideological and political content. Although this practice was widely condemned for its brutality, it proved to be effective at engaging with a variety of international audiences and encouraging potential supporters to seek further information. The reasons for the noteworthy success of this kind of shock-value propaganda content remain unclear, despite many governments’ attempts to produce counterpropaganda. This study examines violent extremist propaganda distributed by five terrorist organizations between 2010 and 2016, using material released by the ‎Al Hayat Media Center of the Islamic State, Boko Haram, Al Qaeda, Al Qaeda in the Arabian Peninsula, and Al Qaeda in the Islamic Maghreb. The time period covers all issues of the infamous publications Inspire and Dabiq, as well as the most shocking video content released by the Islamic State and its affiliates. The study uses frame analysis to distinguish thematic from symbolic content in violent extremist propaganda by contrasting the ways that substantive ideology issues were framed against the use of symbols and violence to garner attention and to stylize propaganda. The results demonstrate that thematic content focuses significantly on diagnostic frames, which explain violent extremist groups’ causes, and prognostic frames, which propose solutions to addressing or rectifying the cause shared by groups and their sympathizers. Conversely, symbolic violence is primarily stylistic and rarely linked to thematic issues or motivational framing. Frame analysis provides a useful preliminary tool in disentangling substantive ideological and political content from stylistic brutality in violent extremist propaganda. This provides governments and researchers a method for better understanding the framing and content used to design narratives and propaganda materials used to promote violent extremism around the world. Increased capacity to process and understand violent extremist narratives will further enable governments and non-governmental organizations to develop effective counternarratives which promote non-violent solutions to extremists’ grievances.

Keywords: countering violent extremism, counternarratives, frame analysis, propaganda, terrorism, violent extremism

Procedia PDF Downloads 174

Authors: Jing-Yang Chung, Chi-Wei Liao, Jing Li, Bor Kae Chang, Cheng-Yu Wang

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Chemical hydride ammonia borane (AB, NH3BH3) draws attentions to hydrogen energy researches for its high theoretical gravimetrical capacity (19.6 wt%). Nevertheless, the elevated AB decomposition temperatures (Td) and unwanted byproducts are main hurdles in practical application. It was reported that the byproducts and Td can be reduced with nanoconfinement technique, in which AB molecules are confined in porous materials, such as porous carbon, zeolite, metal-organic frameworks (MOFs), etc. Although nanoconfinement empirically shows effectiveness on hydrogen generation temperature reduction in AB, the theoretical mechanism is debatable. Low Td was reported in AB@IRMOF-1 (Zn4O(BDC)3, BDC = benzenedicarboxylate), where Zn atoms form closed metal clusters secondary building unit (SBU) with no exposed active sites. Other than nanosized hydride, it was also observed that catalyst addition facilitates AB decomposition in the composite of Li-catalyzed carbon CMK-3, MOF JUC-32-Y with exposed Y3+, etc. It is believed that nanosized AB is critical for lowering Td, while active sites eliminate byproducts. Nonetheless, some researchers claimed that it is the catalytic sites that are the critical factor to reduce Td, instead of the hydride size. The group physically ground AB with ZIF-8 (zeolitic imidazolate frameworks, (Zn(2-methylimidazolate)2)), and found similar reduced Td phenomenon, even though AB molecules were not ‘confined’ or forming nanoparticles by physical hand grinding. It shows the catalytic reaction, not nanoconfinement, leads to AB dehydrogenation promotion. In this research, we explored the possible criteria of hydrogen production temperature from nanoconfined AB in MOFs with different pore sizes and active sites. MOFs with metal SBU such as Zn (IRMOF), Zr (UiO), and Al (MIL-53), accompanying with various organic ligands (BDC and BPDC; BPDC = biphenyldicarboxylate) were modified with AB. Excess MOFs were used for AB size constrained in micropores estimated by revisiting Horvath-Kawazoe model. AB dissolved in methanol was added to MOFs crystalline with MOF pore volume to AB ratio 4:1, and the slurry was dried under vacuum to collect AB@MOF powders. With TPD-MS (temperature programmed desorption with mass spectroscopy), we observed Td was reduced with smaller MOF pores. For example, it was reduced from 100°C to 64°C when MOF micropore ~1 nm, while ~90°C with pore size up to 5 nm. The behavior of Td as a function of AB crystalline radius obeys thermodynamics when the Gibbs free energy of AB decomposition is zero, and no obvious correlation with metal type was observed. In conclusion, we discovered Td of AB is proportional to the reciprocal of MOF pore size, possibly stronger than the effect of active sites.

Keywords: ammonia borane, chemical hydride, metal-organic framework, nanoconfinement

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Authors: Laura Kupers, Julie Piérard, Niki Cauberg

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The use of exposed concrete (sometimes referred to as architectural concrete), keeps gaining popularity. Exposed concrete has the advantage to combine the structural properties of concrete with an aesthetic finish. However, for a successful aesthetic finish, much attention needs to be paid to the execution (formwork, release agent, curing, weather conditions…), the concrete composition (choice of the raw materials and mix proportions) as well as to its fresh properties. For the latter, a simple on-site pass/fail test could halt the casting of concrete not suitable for architectural concrete and thus avoid expensive repairs later. When architects opt for an exposed concrete, they usually want a smooth, uniform and nearly blemish-free surface. For this choice, a standard ‘construction’ concrete does not suffice. An aesthetic surface finishing requires the concrete to contain a minimum content of fines to minimize the risk of segregation and to allow complete filling of more complex shaped formworks. The concrete may neither be too viscous as this makes it more difficult to compact and it increases the risk of blow holes blemishing the surface. On the other hand, too much bleeding may cause color differences on the concrete surface. An easy pass/fail test, which can be performed on the site just before the casting, could avoid these problems. In case the fresh concrete fails the test, the concrete can be rejected. Only in case the fresh concrete passes the test, the concrete would be cast. The pass/fail tests are intended for a concrete with a consistency class S4. Five tests were selected as possible onsite pass/fail test. Two of these tests already exist: the K-slump test (ASTM C1362) and the Bauer Filter Press Test. The remaining three tests were developed by the BBRI in order to test the segregation resistance of fresh concrete on site: the ‘dynamic sieve stability test’, the ‘inverted cone test’ and an adapted ‘visual stability index’ (VSI) for the slump and flow test. These tests were inspired by existing tests for self-compacting concrete, for which the segregation resistance is of great importance. The suitability of the fresh concrete mixtures was also tested by means of a laboratory reference test (resistance to segregation) and by visual inspection (blow holes, structure…) of small test walls. More than fifteen concrete mixtures of different quality were tested. The results of the pass/fail tests were compared with the results of this laboratory reference test and the test walls. The preliminary laboratory results indicate that concrete mixtures ‘suitable’ for placing as exposed concrete (containing sufficient fines, a balanced grading curve etc.) can be distinguished from ‘inferior’ concrete mixtures. Additional laboratory tests, as well as tests on site, will be conducted to confirm these preliminary results and to set appropriate pass/fail values.

Keywords: exposed concrete, testing fresh concrete, segregation resistance, bleeding, consistency

Procedia PDF Downloads 425

Authors: Hung-Chih Hsu, Pey-Jium Chang, Ching-Hsein Chen, Jer-Liang Andrew Yeh

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Osteoarthritis (OA) is a common disorder in rehabilitation clinic. The main characteristics include joint pain, localized tenderness and enlargement, joint effusion, cartilage destruction, loss of adhesion of perichondrium, synovium hyperplasia. Synoviocytes inflammation might be a cause of local tenderness and effusion. Inflammation cytokines might also play an important role in joint pain, cartilage destruction, decrease adhesion of perichondrium to the bone. Treatments of osteoarthritis include non-steroid anti-inflammation drugs (NSAID), glucosamine supplementation, hyaluronic acid, arthroscopic debridement, and total joint replacement. Total joint replacement is commonly used in patients with severe OA who failed respond to pharmacological treatment. However, some patients received surgery had serious adverse events, including instability of the implants due to insufficient adhesion to the adjacent bony tissue or synovial inflammation. We tried to develop ideal nano-topographic oxidized silicon nanosponges by using with various chemicals to produce thickness difference in nanometers in order to study more about the cell-environment interactions in vitro like the alterations of cell adhesion, morphology, extracellular matrix secretions in the pathogenesis of osteoarthritis. Cytokines studies like growth factor, reactive oxygen species, reactive inflammatory materials (Like nitrous oxide and prostaglandin E2), extracellular matrix (ECM) degradation enzymes, and synthesis of collagen will also be observed and discussed. Extracellular and intracellular expression transforming growth factor beta (TGF-β) will be studied by reverse transcription-polymerase chain reaction (RT-PCR). The degradation of ECM will be observed by the bioactivity ratio of matrix metalloproteinase (MMP) and tissue inhibitors of metalloproteinase by ELISA (Enzyme-linked immunosorbent assay). When rabbit synoviocytes were cultured on these nano-topographic structures, they demonstrate better cell adhesion rate, decreased expression of MMP-2,9 and PGE2, and increased expression of TGF-β when cultured in nano-topographic oxidized silicon nanosponges than in the planar oxidized silicon ones. These results show cell behavior, cytokine production can be influenced by physical characteristics from different nano-topographic structures. Our study demonstrates the possibility of manipulating cell behavior in these nano-topographic biomaterials.

Keywords: osteoarthritis, synoviocyte, oxidized silicon surfaces, reactive oxygen species

Procedia PDF Downloads 388

Authors: Baba John, Abdullahi Mohammed

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The aim of this research is to compare the analysis of biodegradation on polythene and plastics buried in fadama soil amended with Organic and Inorganic fertilizer. Physico- chemical properties of the samples were determined. Bacteria and Fungi implicated in the biodegradation were identified and enumerated. Physico- chemical properties before the analysis indicated pH range of the samples from 4.28 – 5.80 , While the percentage Organic carbon and Organic matter was highest in cow dung samples with 3.89% and 6.69% respectively. The total Nitrogen percentage was recorded to be highest in Chicken dropping (0.68), while the availability of Phosphorus (P), Sodium (Na), Pottasium (K), and Magnessium (mg) was recorded to be highest in F – soil (Control), with values to be 37ppm, 1.63 Cmolkg-1, 0.35 Cmolkg-1 and 1.18 Cmolkg-1 respectively, except for calcium which was recorded to be highest in Cow dung (5.80 Cmolkg-1). However, physico – chemical properties of the samples after analysis indicated pH range of 4.6 – 5.80, Percentage Organic carbon and Organic matter was highest in Fadama soil mixed with fertilizer, having 0.7% and 1.2% respectively. Total Percentage Nitrogen content was found to be highest (0.56) in Fadama soil mixed with poultry dropping. Availability of Sodium (Na), Pottasium (K), and Calcium (Ca) was recorded to be highest in Fadama Soil mixed with Cow dung with values to be 0.64 Cmolkg-1, 2.07 Cmolkg-1 and 3.36 Cmolkg-1 respectively. The percentage weight loss of polythene and plastic bags after nine months in fadama soil mixed with poultry dropping was 11.9% for polythene and 6.0% for plastics. Weight loss in fadama soil mixed with cow dung was 18.1% for polythene and 4.7% for plastics. Weight loss of polythene and plastic in fadama soil mixed with fertilizer (NPK) was 7.4% for polythene and 3.3% for plastics. While, the percentage weight loss of polythene and plastics after nine months of burial in fadama soil (control) was 3.5% and 0.0% respectively. The bacteria species isolated from Fadama soil, organic and inorganic fertilizers before amendments include: S. aureus, Micrococcus sp, Streptococcus. pyogenes, Psuedomonas aeruginosa Bacillus subtilis and Bacillus cereus. The fungi species include: Aspergillus niger, Aspergillus fumigatus, Aspergillus flavus, Fusarium sp, Mucor sp Penicillium sp and Candida sp. The bacteria species isolated and characterized after nine months of seeding include: S. aureus, Micrococcus sp, S. pyogenes, P. aeruginosa and B. subtilis. The fungi species are: A. niger A. flavus, A. fumigatus, Mucor sp, Penicillium sp and Fusarium sp. The result of this study indicated that plastic materials can be degraded in the fadama soil irrespective of whether the soil is amended or not. The Period of composting also has a significant impact on the rate at which polythene and plastics are degraded.

Keywords: Fadama, fertilizer, plastic and polythene, biodegradation

Procedia PDF Downloads 544

Authors: Pakize Neslihan Taslı, Alev Cumbul, Gul Merve Yalcın, Fikrettin Sahin

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A key experimental trial in the regeneration of large oral and craniofacial defects is the neogenesis of osseous and ligamentous interfacial structures. Currently, oral regenerative medicine strategies are unpredictable for repair of tooth supporting tissues destroyed as a consequence of trauma, chronic infection or surgical resection. A different approach combining the gel-casting method with Hydroxy Apatite HA-based scaffold and different cell lineages as a hybrid system leads to successively mimic the early stage of tooth development, in vitro. HA is widely accepted as a bioactive material for guided bone and tooth regeneration. In this study, it was reported that, HA porous scaffold preparation, characterization and evaluation of structural and chemical properties. HA is the main factor that exists in tooth and it is in harmony with structural, biological, and mechanical characteristics. Here, this study shows mimicking immature tooth at the late bell stage design and construction of HA scaffolds for cell transplantation of human Adipose Stem Cells (hASCs), human Bone Marrow Stem Cells (hBMSCs) and Gingival Epitelial cells for the formation of human tooth dentin-pulp-enamel complexes in vitro. Scaffold characterization was demonstrated by SEM, FTIR and pore size and density measurements. The biological contraction of dental tissues against each other was demonstrated by mRNA gene expressions, histopatologic observations and protein release profile by ELISA tecnique. The tooth shaped constructs with a pore size ranging from 150 to 300 µm arranged by gathering right amounts of materials provide interconnected macro-porous structure. The newly formed tissue like structures that grow and integrate within the HA designed constructs forming tooth cementum like tissue, pulp and bone structures. These findings are important as they emphasize the potential biological effect of the hybrid scaffold system. In conclusion, this in vitro study clearly demonstrates that designed 3D scaffolds shaped as a immature tooth at the late bell stage were essential to form enamel-dentin-pulp interfaces with an appropriate cell and biodegradable material combination. The biomimetic architecture achieved here is providing a promising platform for dental tissue engineering.

Keywords: tooth regeneration, tissue engineering, adipose stem cells, hydroxyapatite tooth engineering, porous scaffold

Procedia PDF Downloads 234

Authors: Benedetta Caglioti

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The ecclesiastical complex of San Paolo in Ferrara represents a monument of great historical, religious and architectural importance. Its long and articulated story, over time, is already manifested by the mere reading of its planimetric and altimetric configuration, apparently unitary but, in reality, marked by modifications and repeated additions, even of high quality. It follows, in terms of protection, restoration and enhancement, a commitment of due respect for how the ancient building was built and enriched over its centuries of life. Hence a rigorous methodological approach, while being aware of the fact that every monument, in order to live and make use of the indispensable maintenance, must always be enjoyed and visited, therefore it must enjoy, in the right measure and compatibly with its nature, the possibility of improvements and functional, distributive, technological adjustments and related to the safety of people and things. The methodological approach substantiates the different elements of the project (such as distribution functionality, safety, structural solidity, environmental comfort, the character of the site, building and urban planning regulations, financial resources and materials, the same organization methods of the construction site) through the guiding principles of restoration, defined for a long time: the 'minimum intervention,' the 'recognisability' or 'distinguishability' of old and new, the Physico-chemical and figurative 'compatibility,' the 'durability' and the, at least potential, 'reversibility' of what is done, leading to the definition of appropriate "critical choices." The project tackles, together with the strictly functional ones, also the directly conservative and restoration issues, of a static, structural and material technology nature, with special attention to precious architectural surfaces, In order to ensure the best architectural quality through conscious enhancement, the project involves a redistribution of the interior and service spaces, an accurate lighting system inside and outside the church and a reorganization of the adjacent urban space. The reorganization of the interior is designed with particular attention to the issue of accessibility for people with disabilities. To accompany the community to regain possession of the use of the church's own space, already in its construction phase, the project proposal has hypothesized a permeability and flexibility in the management of the works such as to allow the perception of the found Monument to gradually become more and more familiar at the citizenship. Once the interventions have been completed, it is expected that the Church of San Paolo, second in importance only to the Cathedral, from which it is a few steps away, will be inserted in an already existing circuit of use of the city which over the years has systematized the different aspects of culture, the environment and tourism for the creation of greater awareness in the perception of what Ferrara can offer in cultural terms.

Keywords: conservation, accessibility, regeneration, urban space

Procedia PDF Downloads 110

Authors: Madelyn N. Moawad, Hermine R. Z. Tadros, Mary G. Ghobrial, Ahmad R. Bassiouny, Kamal M. Kandeel, Athar Ata

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Seaweeds are potential renewable resources in marine environment. They provide an excellent source of bioactive substances such as dietary fibers and various functional polysaccharides that could potentially be used as ingredients for both human and animal health applications. The observations suggested that these bioactive compounds have strong antioxidant properties, which have beneficial effects on human health. The present research aimed at finding new chemical products from local marine macroalgae for natural medicinal uses and consumption for their nutritional values. Macroalgae samples were collected manually mainly from the Mediterranean Sea at shallow subtidal zone of Abu Qir Bay, Alexandria, Egypt. The chemical compositions of lyophilized materials of six selected macroalgal species; Colpomenia sinuosa, Sargassum linifolium, Padina pavonia, Pterocladiella capillacea, Laurencia pinnatifidia, and Caulerpa racemosa, were investigated for proteins using bovine serum albumin, and carbohydrates were assayed by phenol-sulfuric acid reaction. The macroalgae lipid was extracted with chloroform, methanol and phosphate buffer. Vitamins were extracted using trichloroacetic acid. Chlorophylls and total carotenoids were determined spectrophotometrically and total phenols were extracted with methanol. In addition, lipid-soluble, and water-soluble antioxidant, and anti α-glucosidase activities were measured spectrophotometrically. The antioxidant activity of hexane extracts was investigated using phosphomolybdenum reagent. The anti-α-glucosidase effect measurement was initiated by mixing α-glucosidase solution with p-nitrophenyl α-D-glucopyranoside. The results showed that the ash contents varied from 11.2 to 35.4 % on dry weight basis for P. capillacea and Laurencia pinnatifidia, respectively. The protein contents ranged from 5.63 % in brown macroalgae C. sinuosa to 8.73 % in P. pavonia. A relative wide range in carbohydrate contents was observed (20.06–46.75 %) for the test algal species. The highest lipid percentage was found in green alga C. racemosa (5.91%) followed by brown algae P. pavonia (3.57%) and C. sinuosa (2.64%). The phenolic contents varied from 1.32 mg GAE/g for C. sinuosa to 4.00 mg GAE/g in P. pavonia. The lipid-soluble compounds exhibited higher antioxidant capacity (73.18-145.95 µM/g) than that of the water-soluble ones ranging from 24.83 µM/g in C. racemosa to 74.07 µM/g in S. linifolium. The most potent anti-α-glucosidase activity was observed for P. pavonia with IC50 of 17.12 μg/ml followed by S. linifolium (IC50 = 71.75 μg/ml), C. racemosa (IC50 = 84.73 μg/ml), P. capillacea (IC50 = 92.16 μg/ml), C. sinuosa (IC50 = 112.44 μg/ml), and L. pinnatifida (IC50 = 115.11 μg/ml).

Keywords: α-glucosidase, lyophilized, macroalgae, spectrophotometrically

Procedia PDF Downloads 303

Authors: Cao Bin, Yuan Yi, Wang Qiang, Amor Abdelkader, Ali Reza Kamali, Diogo Montalvão

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The study of the electrodynamic behavior of non-ferrous particles in time-varying magnetic fields is a promising area of research with wide applications, including recycling of non-ferrous metals, mechanical transmission, and space debris. The key technology for recovering non-ferrous metals is eddy current separation (ECS), which utilizes the eddy current force and torque to separate non-ferrous metals. ECS has several advantages, such as low energy consumption, large processing capacity, and no secondary pollution, making it suitable for processing various mixtures like electronic scrap, auto shredder residue, aluminum scrap, and incineration bottom ash. Improving the separation efficiency of mixtures with different particle sizes in ECS can create significant social and economic benefits. Our previous study investigated the influence of particle size on separation efficiency by combining numerical simulations and separation experiments. Pearson correlation analysis found a strong correlation between the eddy current force in simulations and the repulsion distance in experiments, which confirmed the effectiveness of our simulation model. The interaction effects between particle size and material type, rotational speed, and magnetic pole arrangement were examined. It offer valuable insights for the design and optimization of eddy current separators. The underlying mechanism behind the effect of particle size on separation efficiency was discovered by analyzing eddy current and field gradient. The results showed that the magnitude and distribution heterogeneity of eddy current and magnetic field gradient increased with particle size in eddy current separation. Based on this, we further found that increasing the curvature of magnetic field lines within particles could also increase the eddy current force, providing a optimized method to improving the separation efficiency of fine particles. By combining the results of the studies, a more systematic and comprehensive set of optimization guidelines can be proposed for mixtures with different particle size ranges. The separation efficiency of fine particles could be improved by increasing the rotational speed, curvature of magnetic field lines, and electrical conductivity/density of materials, as well as utilizing the eddy current torque. When designing an ECS, the particle size range of the target mixture should be investigated in advance, and the suitable parameters for separating the mixture can be fixed accordingly. In summary, these results can guide the design and optimization of ECS, and also expand the application areas for ECS.

Keywords: eddy current separation, particle size, numerical simulation, metal recovery

Procedia PDF Downloads 91

Authors: S. M. Mabandla, P. Loveday, C. Gomes, D. T. Maiga, T. T. Phadi

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Lead zirconate titanate (PZT) piezoelectric ceramics are widely used in ultrasonic applications due to their ability to effectively convert electrical energy into mechanical vibrations and vice versa. This paper presents a study on the behaviour of various combinations of pairs of PZT piezoelectric ceramic materials positioned adjacent to each other with an intermediate gap submerged in water, where one piezoelectric ceramic material is excited by a cyclic electric field with constant frequency and amplitude displacement. The transmitted ultrasonic sound propagates through the medium and is received by the PZT ceramic at the other end, the ultrasonic sound signal amplitude displacement experiences attenuation during propagation due to acoustic impedance. The investigation focuses on understanding the causes of extremely high amplitude displacement attenuation that have been observed in various combinations of piezoelectric ceramic pairs that are submerged in water arranged in a manner stipulated earlier. by examining various combinations of pairs of these piezoelectric ceramics, their physical, electrical, and acoustic properties, and behaviour and attributing them to the observed significant signal attenuation. The experimental setup involves exciting one piezoelectric ceramic material at one end with a burst square cyclic electric field signal of constant frequency, which generates a burst of ultrasonic sound that propagates through the water medium to the adjacent piezoelectric ceramic at the other end. Mechanical vibrations of a PZT piezoelectric ceramic are measured using a double-beam laser Doppler vibrometer to mimic the incident ultrasonic waves generated and received ultrasonic waves on the other end due to mechanical vibrations of a PZT. The measured ultrasonic sound wave signals are continuously compared to the applied cyclic electric field at both ends. The impedance matching networks are continuously tuned at both ends to eliminate electromechanical impedance mismatch to improve ultrasonic transmission and reception. The study delves into various physical, electrical, and acoustic properties of the PZT piezoelectric ceramics, such as the electromechanical coupling factor, acoustic coupling, and elasticity, among others. These properties are analyzed to identify potential factors contributing to the unusually high acoustic impedance in the water medium between the ceramics. Additionally, impedance-matching networks are investigated at both ends to offset the high signal attenuation and improve overall system performance. The findings will be reported in this paper.

Keywords: acoustic impedance, impedance mismatch, piezoelectric ceramics, ultrasonic sound

Procedia PDF Downloads 79

Authors: K. A. Gladkova, N. P. Babushkina, E. Y. Bragina

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Purpose: Tuberculosis (TB), caused by Mycobacterium tuberculosis, is one of the major public health problems worldwide. It is clear that the immune response to M. tuberculosis infection is a relationship between inflammatory and anti-inflammatory responses in which Tumour Necrosis Factor-α (TNF-α) plays key roles as a pro-inflammatory cytokine. TNF-α involved in various cell immune responses via binding to its two types of membrane-bound receptors, TNFRSF1A and TNFRSF1B. Importantly, some variants of the TNFRSF1B gene have been considered as possible markers of host susceptibility to TB. However, the possible impact of such TNF-α and its receptor genes polymorphism on TB cases in Tomsk is missing. Thus, the purpose of our study was to investigate polymorphism of TNF-α (rs1800629) and its receptor TNFRSF1B (rs652625 and rs525891) genes in population of Tomsk and to evaluate their possible association with the development of pulmonary TB. Materials and Methods: The population distribution features of genes polymorphisms were investigated and made case-control study based on group of people from Tomsk. Human blood was collected during routine patients examination at Tomsk Regional TB Dispensary. Altogether, 234 TB-positive patients (80 women, 154 men, average age is 28 years old) and 205 health-controls (153 women, 52 men, average age is 47 years old) were investigated. DNA was extracted from blood plasma by phenol-chloroform method. Genotyping was carried out by a single-nucleotide-specific real-time PCR assay. Results: First, interpopulational comparison was carried out between healthy individuals from Tomsk and available data from the 1000 Genomes project. It was found that polymorphism rs1800629 region demonstrated that Tomsk population was significantly different from Japanese (P = 0.0007), but it was similar with the following Europeans subpopulations: Italians (P = 0.052), Finns (P = 0.124) and British (P = 0.910). Polymorphism rs525891 clear demonstrated that group from Tomsk was significantly different from population of South Africa (P = 0.019). However, rs652625 demonstrated significant differences from Asian population: Chinese (P = 0.03) and Japanese (P = 0.004). Next, we have compared healthy individuals versus patients with TB. It was detected that no association between rs1800629, rs652625 polymorphisms, and positive TB cases. Importantly, AT genotype of polymorphism rs525891 was significantly associated with resistance to TB (odds ratio (OR) = 0.61; 95% confidence interval (CI): 0.41-0.9; P < 0.05). Conclusion: To the best of our knowledge, the polymorphism of TNFRSF1B (rs525891) was associated with TB, while genotype AT is protective [OR = 0.61] in Tomsk population. In contrast, no significant correlation was detected between polymorphism TNF-α (rs1800629) and TNFRSF1B (rs652625) genes and alveolar TB cases among population of Tomsk. In conclusion, our data expands the molecular particularities associated with TB. The study was supported by the grant of the Russia for Basic Research #15-04-05852.

Keywords: polymorphism, tuberculosis, TNF-α, TNFRSF1B gene

Procedia PDF Downloads 181

Authors: M. François, L. Sigot, C. Vallières

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Volatile Organic Compounds (VOCs) are a real health issue, particularly in domestic indoor environments. Among these VOCs, acetaldehyde is frequently monitored in dwellings ‘air, especially due to smoking and spontaneous emissions from the new wall and soil coverings. It is responsible for respiratory complaints and is classified as possibly carcinogenic to humans. Adsorption processes are commonly used to remove VOCs from the air. Metal-Organic Frameworks (MOFs) are a promising type of material for high adsorption performance. These hybrid porous materials composed of metal inorganic clusters and organic ligands are interesting thanks to their high porosity and surface area. The HKUST-1 (also referred to as MOF-199) is a copper-based MOF with the formula [Cu₃(BTC)₂(H₂O)₃]n (BTC = benzene-1,3,5-tricarboxylate) and exhibits unsaturated metal sites that can be attractive sites for adsorption. The objective of this study is to investigate the impact of HKUST-1 pretreatment on acetaldehyde adsorption. Thus, dynamic adsorption experiments were conducted in 1 cm diameter glass column packed with 2 cm MOF bed height. MOF were sieved to 630 µm - 1 mm. The feed gas (Co = 460 ppmv ± 5 ppmv) was obtained by diluting a 1000 ppmv acetaldehyde gas cylinder in air. The gas flow rate was set to 0.7 L/min (to guarantee a suitable linear velocity). Acetaldehyde concentration was monitored online by gas chromatography coupled with a flame ionization detector (GC-FID). Breakthrough curves must allow to understand the interactions between the MOF and the pollutant as well as the impact of the HKUST-1 humidity in the adsorption process. Consequently, different MOF water content conditions were tested, from a dry material with 7 % water content (dark blue color) to water saturated state with approximately 35 % water content (turquoise color). The rough material – without any pretreatment – containing 30 % water serves as a reference. First, conclusions can be drawn from the comparison of the evolution of the ratio of the column outlet concentration (C) on the inlet concentration (Co) as a function of time for different HKUST-1 pretreatments. The shape of the breakthrough curves is significantly different. The saturation of the rough material is slower (20 h to reach saturation) than that of the dried material (2 h). However, the breakthrough time defined for C/Co = 10 % appears earlier in the case of the rough material (0.75 h) compared to the dried HKUST-1 (1.4 h). Another notable difference is the shape of the curve before the breakthrough at 10 %. An abrupt increase of the outlet concentration is observed for the material with the lower humidity in comparison to a smooth increase for the rough material. Thus, the water content plays a significant role on the breakthrough kinetics. This study aims to understand what can explain the shape of the breakthrough curves associated to the pretreatments of HKUST-1 and which mechanisms take place in the adsorption process between the MOF, the pollutant, and the water.

Keywords: acetaldehyde, dynamic adsorption, HKUST-1, pretreatment influence

Procedia PDF Downloads 239

Authors: Karolina Ordon, Sandrine Coste, Malgorzata Makowska-Janusik, Abdelhadi Kassiba

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Photocatalytic processes play key role in the production of a new source of energy (as hydrogen), design of self-cleaning surfaces or for the environment preservation. The most challenging task deals with the purification of water distinguished by high efficiency. In the mentioned process, organic pollutants in solutions are decomposed to the simple, non-toxic compounds as H2O and CO2. The most known photocatalytic materials are ZnO, CdS and TiO2 semiconductors with a particular involvement of TiO2 as an efficient photocatalysts even with a high band gap equal to 3.2 eV which exploit only UV radiation from solar emitted spectrum. However, promising material with visible light induced photoactivity was searched through the monoclinic polytype of BiVO4 which has energy gap about 2.4 eV. As required in heterogeneous photocatalysis, the high contact surface is required. Also, BiVO4 as photocatalyst can be optimized by increasing its surface area by achieving the mesoporous structure synthesize. The main goal of the present work consists in the synthesis and characterization of BiVO4 mesoporous thin film. The synthesis method based on sol-gel was carried out using a standard surfactants such as P123 and F127. The thin film was deposited by spin and dip coating method. Then, the structural analysis of the obtained material was performed thanks to X-ray diffraction (XRD) and Raman spectroscopy. The surface of resulting structure was investigated using a scanning electron microscopy (SEM). The computer simulations based on modeling the optical and electronic properties of bulk BiVO4 by using DFT (density functional theory) methodology were carried out. The semiempirical parameterized method PM6 was used to compute the physical properties of BiVO4 nanostructures. The Raman and IR absorption spectra were also measured for synthesized mesoporous material, and the results were compared with the theoretical predictions. The simulations of nanostructured BiVO4 have pointed out the occurrence of quantum confinement for nanosized clusters leading to widening of the band gap. This result overcame the relevance of nanosized objects to harvest wide part of the solar spectrum. Also, a balance was searched experimentally through the mesoporous nature of the films devoted to enhancing the contact surface as required for heterogeneous catalysis without to lower the nanocrystallite size under some critical sizes inducing an increased band gap. The present contribution will discuss the relevant features of the mesoporous films with respect to their photocatalytic responses.

Keywords: bismuth vanadate, photocatalysis, thin film, quantum-chemical calculations

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Authors: Ali Hashemifarzad, Jens Zum Hingst

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The structure of the world’s energy systems has changed significantly over the past years. One of the most important challenges in the 21st century in Germany (and also worldwide) is the energy transition. This transition aims to comply with the recent international climate agreements from the United Nations Climate Change Conference (COP21) to ensure sustainable energy supply with minimal use of fossil fuels. Germany aims for complete decarbonization of the energy sector by 2050 according to the federal climate protection plan. One of the stipulations of the Renewable Energy Sources Act 2017 for the expansion of energy production from renewable sources in Germany is that they cover at least 80% of the electricity requirement in 2050; The Gross end energy consumption is targeted for at least 60%. This means that by 2050, the energy supply system would have to be almost completely converted to renewable energy. An essential basis for the development of such a sustainable energy supply from 100% renewable energies is to predict the energy requirement by 2050. This study presents two scenarios for the final energy demand in Germany in 2050. In the first scenario, the targets for energy efficiency increase and demand reduction are set very ambitiously. To build a comparison basis, the second scenario provides results with less ambitious assumptions. For this purpose, first, the relevant framework conditions (following CUTEC 2016) were examined, such as the predicted population development and economic growth, which were in the past a significant driver for the increase in energy demand. Also, the potential for energy demand reduction and efficiency increase (on the demand side) was investigated. In particular, current and future technological developments in energy consumption sectors and possible options for energy substitution (namely the electrification rate in the transport sector and the building renovation rate) were included. Here, in addition to the traditional electricity sector, the areas of heat, and fuel-based consumptions in different sectors such as households, commercial, industrial and transport are taken into account, supporting the idea that for a 100% supply from renewable energies, the areas currently based on (fossil) fuels must be almost completely be electricity-based by 2050. The results show that in the very ambitious scenario a final energy demand of 1,362 TWh/a is required, which is composed of 818 TWh/a electricity, 229 TWh/a ambient heat for electric heat pumps and approx. 315 TWh/a non-electric energy (raw materials for non-electrifiable processes). In the less ambitious scenario, in which the targets are not fully achieved by 2050, the final energy demand will need a higher electricity part of almost 1,138 TWh/a (from the total: 1,682 TWh/a). It has also been estimated that 50% of the electricity revenue must be saved to compensate for fluctuations in the daily and annual flows. Due to conversion and storage losses (about 50%), this would mean that the electricity requirement for the very ambitious scenario would increase to 1,227 TWh / a.

Keywords: energy demand, energy transition, German Energiewende, 100% renewable energy production

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Authors: Sevket Ceyhun Cetin, Mehmet Oren

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According to existing educational research studies, students learn better with high teacher quality. Therefore, professional development has become a crucial way of increasing the quality of novices and veteran in-service teachers by providing support regarding content and pedagogy. To answer what makes PD effective, researchers have studied different PD models and revealed some critical elements that need to be considered, such as duration of a PD and the manner of delivery (e.g., lecture vs. engaging). Also, it has been pointed out that if PDs are prepared as one-size-fits-all, they most likely be ineffective in addressing teachers’ needs toward improving instructional quality. Instead, teachers’ voices need to be heard, and the foci of PDs should be determined based on their specific needs. Thus, this study was conducted to identify professional development needs of middle school mathematics teachers based on their self-evaluation of their performances in light of teaching standards. This study also aimed to explore whether the PD needs with respect to years of teaching experience (novice vs. veteran). These teachers had participated in a federally-funded research grant, which aimed to improve the competencies of 6-9 grade-level mathematics teachers in pedagogy and content areas. In the research project, the participants had consistently videoed their lessons throughout a school year and reflected on their performances, using Teacher Advanced Program (TAPTM) rubric, which was based on the best practices of teaching. Particularly, they scored their performances in the following areas and provided evidence as the justifications of their scores: Standards and Objectives, Presenting Instructional Content, Lesson Structure and Pacing, Activities and Materials, Academic Feedback, Grouping Students, and Questioning. The rating scale of the rubric is 1 through 5 (i.e., 1=Unsatisfactory [performance], 3=Proficient, and 5=Exemplary). For each area mentioned above, the numerical scores of 77 written reports (for 77 videoed lessons) of 24 teachers (nnovices=12 and nveteran=12) were averaged. Overall, the average score of each area was below 3 (ranging between 2.43 and 2.86); in other words, teachers judged their performances incompetent across the seven areas. In the second step of the data analysis, the lowest three areas in which novice and veteran teachers performed poorly were selected for further qualitative analysis. According to the preliminary results, the lowest three areas for the novice teachers were: Questioning, Grouping Students, and Academic Feedback. Grouping Students was also one of the lowest areas of the veteran teachers, but the other two areas for this group were: Lesson Structure & Pacing, and Standards & Objectives. Identifying in-service teachers’ needs based on their reflective practitioner experiences provides educators very crucial information that can be used to create more effective PD that improves teacher quality.

Keywords: mathematics teacher, professional development, self-reflection, video data

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Authors: Hela Ghali, Sihem Ben Fredj, Mohamed Ben Rejeb, Sawssen Layouni, Salwa Khefacha, Lamine Dhidah, Houyem Said Laatiri

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Background: Antimicrobial resistance is a growing threat to public health and motivates to improve prevention and control programs both at international (WHO) and national levels. Despite their low pathogenicity, vancomycin-resistant enterococci (VRE) are common nosocomial pathogens in several countries. The high potential for transmission of VRE between patients and the threat to send its resistance genes to other bacteria such as staphylococcus aureus already resistant to meticilin, justify strict control measures. Indeed, in Europe, the proportion of Enterococcus faecium responsible for invasive infections, varies from 1% to 35% in 2011 and less than 5% were resistant to vancomycin. In addition, it represents the second cause of urinary tract and wound infections and the third cause of nosocomial bacteremia in the United States. The nosocomial outbreaks of VRE have been mainly described in intensive care services, hematology-oncology and haemodialysis. An epidemic of VRE has affected our hospital and the objective of this work is to describe the measures put in place. Materials/Methods: Following the alert given by the service of plastic surgery concerning a patient carrier of VRE, a team of the prevention and healthcare security service (doctor + technician) made an investigation. A review of files was conducted to draw the synoptic table and the table of cases. Results: By contacting the microbiology laboratory, we have identified four other cases of VRE and who were hospitalized in Medical resuscitation department (2 cases, one of them was transferred to the Physical rehabilitation department), and Nephrology department (2 cases). The visit has allowed to detect several malfunctions in professional practice. A crisis cell has allowed to validate, coordinate and implement control measures following the recommendations of the Technical Center of nosocomial infections. In fact, the process was to technically isolate cases in their sector of hospitalization, to restrict the use of antibiotics, to strength measures of basic hygiene, and to make a screening by rectal swab for both cases and contacts (other patients and health staff). These measures have helped to control the situation and no other case has been reported for a month. 2 new cases have been detected in the intensive care unit after a month. However, these are short-term strategies, and other measures in the medium and long term should be taken into account in order to face similar outbreaks. Conclusion: The efforts to control the outbreak were not efficient since 2 new cases have been reported after a month. Therefore, a continuous monitoring in order to detect new cases earlier is crucial to minimize the dissemination of VRE.

Keywords: hospitals, nosocomial infection, outbreak, vancomycin-resistant enterococci

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Authors: A. J. Cobley, L. Krishnan

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The demand for multi-functional lightweight materials in sectors such as automotive, aerospace, electronics is growing, and for this reason fibre-reinforced, epoxy polymer composites are being widely utilized. The fibre reinforcing material is mainly responsible for the strength and stiffness of the composites whilst the main role of the epoxy polymer matrix is to enhance the load distribution applied on the fibres as well as to protect the fibres from the effect of harmful environmental conditions. The superior properties of the fibre-reinforced composites are achieved by the best properties of both of the constituents. Although factors such as the chemical nature of the epoxy and how it is cured will have a strong influence on the properties of the epoxy matrix, the method of mixing and degassing of the resin can also have a significant impact. The production of a fibre-reinforced epoxy polymer composite will usually begin with the mixing of the epoxy pre-polymer with a hardener and accelerator. Mechanical methods of mixing are often employed for this stage but such processes naturally introduce air into the mixture, which, if it becomes entrapped, will lead to voids in the subsequent cured polymer. Therefore, degassing is normally utilised after mixing and this is often achieved by placing the epoxy resin mixture in a vacuum chamber. Although this is reasonably effective, it is another process stage and if a method of mixing could be found that, at the same time, degassed the resin mixture this would lead to shorter production times, more effective degassing and less voids in the final polymer. In this study the effect of four different methods for mixing and degassing of the pre-polymer with hardener and accelerator were investigated. The first two methods were manual stirring and magnetic stirring which were both followed by vacuum degassing. The other two techniques were ultrasonic mixing/degassing using a 40 kHz ultrasonic bath and a 20 kHz ultrasonic probe. The cured cast resin samples were examined under scanning electron microscope (SEM), optical microscope, and Image J analysis software to study morphological changes, void content and void distribution. Three point bending test and differential scanning calorimetry (DSC) were also performed to determine the thermal and mechanical properties of the cured resin. It was found that the use of the 20 kHz ultrasonic probe for mixing/degassing gave the lowest percentage voids of all the mixing methods in the study. In addition, the percentage voids found when employing a 40 kHz ultrasonic bath to mix/degas the epoxy polymer mixture was only slightly higher than when magnetic stirrer mixing followed by vacuum degassing was utilized. The effect of ultrasonic mixing/degassing on the thermal and mechanical properties of the cured resin will also be reported. The results suggest that low frequency ultrasound is an effective means of mixing/degassing a pre-polymer mixture and could enable a significant reduction in production times.

Keywords: degassing, low frequency ultrasound, polymer composites, voids

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Authors: Carolina Schencke, Cristian Sandoval, Belgica Vasquez, Mariano Del Sol

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Introduction: In a burn injury, the successful repair requires not only the participation of various cells, such as granulocytes and fibroblasts, but also of collagen, which plays a crucial role as a structural and regulatory molecule of scar tissue. Since honey and ascorbic acid have presented a great therapeutic potential to cellular and structural level, experimental studies have proposed its combination in the treatment of wounds. Aim: To evaluate stereological and morphometric parameters of healing wounds, caused by burns, treated with honey Ulmo (Eucryphia cordifolia) unsupplemented, comparing its effect with Ulmo honey supplemented with ascorbic acid. Materials and Methods: Fifteen healthy adult guinea pigs (Cavia porcellus) were used, of both sexes, average weight 450 g from the Centro de Excelencia en Estudios Morfológicos y Quirúrgicos (CEMyQ) at the Universidad de La Frontera, Chile. The animals were divided at random into three groups: positive control (C+), honey only (H) and supplemented honey (SH) and were fed on pellets supplemented with ascorbic acid and water ad libitum, under ambient conditions controlled for temperature, ambient noise and a cycle of 12h light–darkness. The protocol for the experiment was approved by the Scientific Ethics Committee of the Universidad de La Frontera, Chile. The parameters measured were number density per area (NA), volume density (VV), and surface density (SV) of fibroblast; NA and VV of polymorphonuclear cells (PMN) and, evaluation of the content of collagen fibers in the scar dermis. One-way ANOVA was used for statistics analysis and its respective Post hoc tests. Results: The ANOVA analysis for NA, VV and SV of fibroblasts, NA and VV of PMN, and evaluation of collagen content, type I and III, showed that at least one group differs from other (P≤ 0.001). There were differences (P= 0.000) in NA of fibroblast between the groups [C+= 3599.560 mm-2 (SD= 764.461), H= 3355.336 mm-2 (SD= 699.443) and SH= 4253.025 mm-2 (SD= 1041.751)]. The VV and SV of fibroblast increased (P= 0.000) in the SH group [20.400% (SD= 5.897) and 100.876 mm2/mm3 (SD= 29.431), respectively], compared to the C+ [16.324% (SD= 7.719) and 81.676 mm2/mm3 (SD= 28.884), respectively). The mean values of NA and VV of PMN were higher (P= 0.000) in the H [756.875 mm-2 (SD= 516.489) and 2.686% (SD= 2.380), respectively) group. Regarding to the evaluation of the content of collagen fibers, type I and III, the one-way analysis of ANOVA showed a statistically significant difference (P< 0.05). The content of collagen fibers type I was higher in C+ (1988.292 μm2; SD= 1312.379), while the content of collagen fibers type III was higher in SH (1967.163 μm2; SD= 1047.944 μm2) group. Conclusions: The stereological results were correlated with the stage of healing observed for each group. These results suggest that the combination of honey with ascorbic acid potentiate the healing effect, where both participated synergistically.

Keywords: ascorbic acid, morphometry, stereology, Ulmo honey

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