Search results for: quantum chemical studies

Authors: Reza Sadeghi, Maryam Nazarahari

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Considering the effectiveness of plant pesticides in pest control, this group of pesticides can provide an efficient way to reduce the damage caused by pests in agriculture and maintain environmental health. Plant pesticides allow farmers to cultivate their crops by lowering the use of chemical pesticides and help improve the quality of agricultural products. In this research, various plant compounds were extracted from two different sources, thyme and eucalyptus, by using n-hexane solvent and investigated to control cotton bollworm in laboratory conditions. The mortality rates of cotton bollworm (Helicoverpa armigera) caused by different concentrations of hexanic extract formulations were evaluated. The results showed that the varied concentrations of the hexanic extract formulations of thyme and eucalyptus had significant effects on the mortality rates of cotton bollworm larvae during a 24-h exposure period. The hexanic extract of thyme as a plant pesticide can be an effective alternative in agriculture and plant pest control. The use of pesticides in agriculture can help the environment and reduce the problems related to chemical toxins. Also, this research revealed that the types and compounds of plant pesticides can be effective in pest control and help to develop more efficient agricultural strategies.

Keywords: cotton bollworm, thyme, eucalyptus, extract formulation, toxicity

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Authors: M. A. Adejumobi, J. O. Ojediran

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The aim of irrigation is to recharge the available water in the soil. Quality of irrigation water is essential for the yield and quality of crops produced, maintenance of soil productivity and protection of the environment. The analysis of irrigation water arises as a need to know the impact of irrigation water on the yield of crops, the effect, and the necessary control measures to rectify the effect of this for optimum production and yield of crops. This study was conducted to assess the quality of irrigation water with its performance on crop planted, in Josepdam irrigation scheme Bacita, Nigeria. Field visits were undertaken to identify and locate water supply sources and collect water samples from these sources; X1 Drain, Oshin, River Niger loop and Ndafa. Laboratory experiments were then undertaken to determine the quality of raw water from these sources. The analysis was carried for various parameters namely; physical and chemical analyses after water samples have been taken from four sources. The samples were tested in laboratory. Results showed that the raw water sources shows no salinity tendencies with SAR values less than 1me/l and Ecvaules at Zero while the pH were within the recommended range by FAO, there are increase in potassium and sulphate content contamination in three of the location. From this, it is recommended that there should be proper monitoring of the scheme by conducting analysis of water and soil in the environment, preferable test should be carried out at least one year to cover the impact of seasonal variations and to determine the physical and chemical analysis of the water used for irrigation at the scheme.

Keywords: irrigation, salinity, raw water quality, scheme

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Authors: Benhamouda Sara, Guezouli Larbi

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Nowadays, the dissemination of information touches the distributed world, where selecting the relevant servers to a user request is an important problem in distributed information retrieval. During the last decade, several research studies on this issue have been launched to find optimal solutions and many approaches of collection selection have been proposed. In this paper, we propose a new collection selection approach that takes into consideration the number of documents in a collection that contains terms of the query and the weights of those terms in these documents. We tested our method and our studies show that this technique can compete with other state-of-the-art algorithms that we choose to test the performance of our approach.

Keywords: distributed information retrieval, relevance, server selection, collection selection

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Authors: Salah Mohammed Al-Eid, Siddig Hussein Hamad, Fahad Mohammed Aljassas

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The effects of high hydrostatic pressure (HHP) treatments on microbial contamination, chemical and physical properties of fresh dates (Rutab stage) were studied. Khalas, Barhi and Hilali cultivars were treated at 200, 250, 300 and 350 MPa using HHP research apparatus. The objective of such treatments was to preserve fresh dates without adversely affecting its properties. Treating fresh dates at 300 MPa for 5 minutes at 40°C reduced microbial contamination in about 2.5 log cycles. Applying 250 MPa was enough to control Rutab contamination with molds, yeasts, and coliforms. Both treatments were enough to reduce Rutab microbial contamination to acceptable levels. HHP caused no significant effect on Rutab chemical properties (moisture, sugars, protein, pectin and acidity). However, a slight decrease in moisture contents due to HHP was observed. Rutab lightness (L*) significantly decreased due to the application of HHP. Only Rutab treated at 300 MPs gave lower redness (a*) values compared with an untreated sample. The effect of 300 MPa on increasing yellowness (b*) was observed for Barhi and Hilali but decreasing for Khalas. The hardness of all Rutab cultivars significantly decreased as a result of HHP application. In fact, the pressure applied at 300 MPa had an adverse effect on texture, which may limit its suitability for use in Rutab preservation.

Keywords: high hydrostatic pressure, fresh dates (Rutab), microbial contamination, color, texture

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Authors: Zsanett Bahor, Cristina Nunes-Fonseca, Gillian L. Currie, Emily S. Sena, Lindsay D.G. Thomson, Malcolm R. Macleod

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Psychosis is ranked as the third most disabling medical condition in the world by the World Health Organization. Despite a substantial amount of research in recent years, available treatments are not universally effective and have a wide range of adverse side effects. Since many clinical drug candidates are identified through in vivo modelling, a deeper understanding of these models, and their strengths and limitations, might help us understand reasons for difficulties in psychosis drug development. To provide an unbiased summary of the preclinical psychosis literature we performed a systematic electronic search of PubMed for publications modelling a psychotic disorder in vivo, identifying 14,721 relevant studies. Double screening of 11,000 publications from this dataset so far established 2403 animal studies of psychosis, with the most common model being schizophrenia (95%). 61% of these models are induced using pharmacological agents. For all the models only 56% of publications test a therapeutic treatment. We propose a systematic review of these studies to assess the prevalence of reporting of measures to reduce risk of bias, and a meta-analysis to assess the internal and external validity of these animal models. Our findings are likely to be relevant to future preclinical studies of psychosis as this generation of strong empirical evidence has the potential to identify weaknesses, areas for improvement and make suggestions on refinement of experimental design. Such a detailed understanding of the data which inform what we think we know will help improve the current attrition rate between bench and bedside in psychosis research.

Keywords: animal models, psychosis, systematic review, schizophrenia

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Authors: Vu Hoang Thu Huong

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Background: Surface electrical stimulation (SES) is a popular non-invasive approach that offers a wide range of treatments for many diseases of physical therapy. It involves applying electrical stimulation to the skin via surface electrodes to stimulate nerve fibers. SES was regularly used to treat the back and upper or lower extremities, but it was rarely used to treat the chest and abdomen. SES on the thorax and abdomen should be administered with more attention because crucial organs are under those areas (i.e., heart, lungs, liver, etc.). In these areas, safety precautions are suggested, and some SES applications might even be a contraindication. The fact that physical therapists have less experience with SES in these situations can also be attributed to these. Although a few earlier studies applied it to these settings and discovered hopeful results, none of them highlight the relationship between the intensity of SES and its depth of impact for safety considerations. Objective: To assure feasibility when using SES in these areas, the purpose of this study is to summarize the common location and intensity of those areas that have been conducted in previous studies. Method: A thorough systematic review was conducted to determine the common surface electrode position for the thorax and abdomen areas. The studies with the randomized controlled design were systematically searched using inclusion and exclusion criteria through nine electronic databases, including Pubmed, Scopus, etc., between 1975 and Dec 2021. Results: Thirty-three studies with over 1800 participants and 4 types of SES (TENS, IFC, NMES, and FES) with various categories of department hospitals were found. Following an anterior, lateral, and posterior observation, the particular SES positions found that it concentrated on 6 regions (the thoracic, abdomen, upper lateral, lower lateral, upper back, and lower back regions), and its intensity for each region was also summarized. Conclusion: This systematic review figured out the popular locations of SES in the thorax and abdominal areas as well as a summarized maximum of intensity that was found in previous studies with outstanding outcomes.

Keywords: surface electrical stimulation, electrical stimulation, thoracic, abdomen, abdominal.

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Authors: A. O. Adebayo, G. A. Idowu, F. Odegbemi

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Investigations on the recovery of nickel from aqueous solution using 2-hydroxy-5-nonyl- acetophenone oxime (LIX-84I) impregnated on activated charcoal was carried out. The LIX-84I was impregnated onto the pores of dried activated charcoal by dry method and optimum conditions for different equilibrium parameters (pH, adsorbent dosage, extractant concentration, agitation time and temperature) were determined using a simulated solution of nickel. The kinetics and adsorption isotherm studies were also evaluated. It was observed that the efficiency of recovery with LIX-84I impregnated on charcoal was dependent on the pH of the aqueous solution as there was little or no recovery at pH below 4. However, as the pH was raised, percentage recovery increases and peaked at pH 5.0. The recovery was found to increase with temperature up to 60ºC. Also it was observed that nickel adsorbed onto the loaded charcoal best at a lower concentration (0.1M) of the extractant when compared with higher concentrations. Similarly, a moderately low dosage (1 g) of the adsorbent showed better recovery than larger dosages. These optimum conditions were used to recover nickel from the leachate of Ni-MH batteries dissolved with sulphuric acid, and a 99.6% recovery was attained. Adsorption isotherm studies showed that the equilibrium data fitted best to Temkin model, with a negative value of constant, b (-1.017 J/mol) and a high correlation coefficient, R² of 0.9913. Kinetic studies showed that the adsorption process followed a pseudo-second order model. Thermodynamic parameter values (∆G⁰, ∆H⁰, and ∆S⁰) showed that the adsorption was endothermic and spontaneous. The impregnated charcoal appreciably recovered nickel using a relatively smaller volume of extractant than what is required in solvent extraction. Desorption studies showed that the loaded charcoal is reusable for three times, and so might be economical for nickel recovery from waste battery.

Keywords: charcoal, impregnated, LIX-84I, nickel, recovery

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Authors: Robert Kwame Kpaliba, Dennis Kpakpor Adotey, Yaw Serfor-Armah

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Increase in the oceanic carbon dioxide absorbance from the atmosphere due to climate change has led to appreciable change in the chemistry of the oceans. The change in oceanic pH referred to as ocean acidification poses multiple threats and stresses on marine species, biodiversity, goods and services, and livelihoods. Marine ecosystems are continuously threatened by plethora of natural and anthropogenic stressors including carbon dioxide (CO₂) emissions causing a lot of changes which has not been experienced for approximately 60 years. Little has been done in Africa as a whole and Ghana in particular to improve the understanding of the variations of the carbonate chemistry of seawater and the biophysical impacts of ocean acidification on security of seafood, nutrition, climate and environmental change. There is, therefore, the need for regular monitoring of carbonate chemistry of seawater along Ghana’s coastline to generate reliable data to aid marine policy formulation. Samples of seawater were collected thrice every month for a one-year period from five study sites for the various parameters to be analyzed. Analysis of the measured physico-chemical and the carbonate chemistry parameters was done using simple statistics. Correlation test and ANOVA were run on both of the physico-chemical and carbonate chemistry parameters. The carbonate chemistry parameters were measured using computer software programme (CO₂cal v4.0.9) except total alkalinity and pH. The study assessed the variability of seawater carbonate chemistry in selected portions of the Central Atlantic Coastline of Ghana (Tsokomey/Bortianor, Kokrobitey, Gomoa Nyanyanor, Gomoa Fetteh, and Senya Breku landing beaches) over a 1-year period (June 2016–May 2017). For physico-chemical parameters, there was insignificant variation in nitrate (NO₃⁻) (1.62 - 2.3 mg/L), ammonia (NH₃) (1.52 - 2.05 mg/L), and salinity (sal) (34.50 - 34.74 ppt). Carbonate chemistry parameters for all the five study sites showed significant variation: partial pressure of carbon dioxide (pCO₂) (414.08-715.5 µmol/kg), carbonate ion (CO₃²⁻) (115-157.92 µmol/kg), pH (7.9-8.12), total alkalinity (TA) (1711.8-1986 µmol/kg), total carbon dioxide (TCO₂) (1512.1 - 1792 µmol/kg), dissolved carbon dioxide (CO₂aq) (10.97-18.92 µmol/kg), Revelle Factor (RF) (9.62-11.84), aragonite (ΩAr) (0.75-1.48) and calcite (ΩCa) (1.08-2.14). The study revealed that the partial pressure of carbon dioxide and temperature did not have a significant effect on each other (r² = 0.31) (p-value = 0.0717). There was an appreciable effect of pH on dissolved carbon dioxide (r² = 0.921) (p-value = 0.0000). The variation between total alkalinity and dissolved carbon dioxide was appreciable (r² = 0.731) (p-value = 0.0008). There was a significant correlation between total carbon dioxide and dissolved carbon dioxide (r² = 0.852) (p-value = 0.0000). Revelle factor correlated strongly with dissolved carbon dioxide (r² = 0.982) (p-value = 0.0000). Partial pressure of carbon dioxide corresponds strongly with atmospheric carbon dioxide (r² = 0.9999) (p-value = 0.00000).

Keywords: carbonate chemistry, seawater, central atlantic coastline, Ghana, ocean acidification

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Authors: Rylle Evan Gabriel Zamora, Micah Dennise Malia, Abygail Deniese Villabona

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When examining studies on aggression, the studies about individual aggression vastly outnumbers those studies on group aggression. Given the nature of aggression to be violent and cyclical, and the amount violent events that have occurred in the near present, the study of group aggression is relevant now more than ever. This discrepancy is parallel with the number of valid and reliable psychological tests that measure group aggression. Throughout history, one of the biggest causes of group based violence and aggression is religion. This is particularly true within the context of the Philippines as there are a large number of religious groups. Thus, this study aimed to develop a standardized test that measures an individual’s tendency to be aggressive to those who are in conflict with his or her religious beliefs. This study employs a test development design that employs a qualitative phase to ensure the validity of the scale. Thus, the study was divided into three phases. First is a pilot test wherein an instrument was designed from existing literature which was then administered to 173 respondents from the four largest religious groups in the Philippines. After extensive factor analysis and reliability testing, new items were then formed from the qualitative data collected from eight participants, consisting of two individuals per religious group. The final testing integrates all statistically significant items from the first phase, and the newly formed items from the second phase, which was then administered to 200 respondents. The results were then tested further for reliability using Cronbach’s alpha and validity through factor analysis. The items that were proven to be significant were then combined to create a final instrument that may be used by future studies.

Keywords: religious aggression, group aggression, test development, psychological assessment, social psychology

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Authors: H. Al-Baghli, F. Al-Asfour

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The current applied asphalt technology for Kuwait roads pavement infrastructure is the hot mix asphalt (HMA) pavement, including both pen grade and polymer modified bitumen (PMBs), that is produced and compacted at high temperature levels ranging from 150 to 180 °C. There are no current specifications for warm and cold mix asphalts in Kuwait’s Ministry of Public Works (MPW) asphalt standard and specifications. The process of the conventional HMA is energy intensive and directly responsible for the emission of greenhouse gases and other environmental hazards into the atmosphere leading to significant environmental impacts and raising health risk to labors at site. Warm mix asphalt (WMA) technology, a sustainable alternative preferred in multiple countries, has many environmental advantages because it requires lower production temperatures than HMA by 20 to 40 °C. The reduction of temperatures achieved by WMA originates from multiple technologies including foaming and chemical or organic additives that aim to reduce bitumen and improve mix workability. This paper presents a literature review of WMA technologies and techniques followed by an experimental study aiming to compare the results of produced WMA samples, using a water containing additive (foaming process), at different compaction temperatures with the HMA control volumetric properties mix designed in accordance to the new MPW’s specifications and guidelines.

Keywords: warm-mix asphalt, water-bearing additives, foaming-based process, chemical additives, organic additives

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Authors: Nawaf Alotaibi, Andy Evans, Alison Heppenstall, Nick Malleson

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Throughout the last two decades, motor vehicle theft (MVT) has accounted for the largest proportion of property crime incidents in Saudi Arabia (SA). However, to date, few studies have investigated SA’s MVT problem. Those that have are primarily focused on the characteristics of car thieves, and most have overlooked any spatial-temporal distribution of MVT incidents and the characteristics of victims. This paper represents the first step in understanding this problem by reviewing the existing MVT studies contextualised within the theoretical frameworks developed in environmental criminology theories – originating in the West – and exploring to what extent they are relevant to the SA context. To achieve this, the paper has identified a range of key features in SA that are different from typical Western contexts, that could limit the appropriateness and capability of applying existing environmental criminology theories. Furthermore, despite these Western studies reviewed so far having introduced a number of explanatory variables for MVT rates, a range of significant elements are apparently absent in the current literature and this requires further analysis. For example, almost no attempts have been made to quantify the associations between the locations of vehicle theft, recovery of stolen vehicles, joyriding and traffic volume.

Keywords: environmental criminology theories, motor vehicle theft, Saudi Arabia, spatial analysis

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Authors: Kianoosh Samimi, Farhad Estakhr, Mahdi Mahdikhani, Faramaz Moodi

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Due to their fluidity and simplicity of use, self-compacting concretes (SCCs) have undeniable advantages. In recent years, the role of metakaolin as a one of pozzolanic materials in concrete has been considered by researchers. It can modify various properties of concrete, due to high pozzolanic reactions and also makes a denser microstructure. The objective of this paper is to examine the influence of three type of Portland cement and metakaolin on fresh state, compressive strength and sulfuric acid attacks in self- consolidating concrete at early age up to 90 days of curing in lime water. Six concrete mixtures were prepared with three types of different cement as Portland cement type II, Portland Slag Cement (PSC), Pozzolanic Portland Cement (PPC) and 15% substitution of metakaolin by every cement. The results show that the metakaolin admixture increases the viscosity and the demand amount of superplasticizer. According to the compressive strength results, the highest value of compressive strength was achieved for PSC and without any metakaolin at age of 90 days. Conversely, the lowest level of compressive strength at all ages of conservation was obtained for PPC and containing 15% metakaolin. According to this study, the total substitution of PSC and PPC by Portland cement type II is beneficial to the increasing in the chemical resistance of the SCC with respect to the sulfuric acid attack. On the other hand, this increase is more noticeable by the use of 15% of metakaolin. Therefore, it can be concluded that metakaolin has a positive effect on the chemical resistance of SCC containing of Portland cement type II, PSC, and PPC.

Keywords: SCC, metakaolin, cement type, durability, compressive strength, sulfuric acid attacks

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Authors: Djeddi Hamssa, Kherief Necereddine Saliha, Mehennaoui Fatima Zohra

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The objectives of this study are to use different parameters to assess the current pollution status of sediments in Rhumel wadi located in the North-East of Algeria (Constantine), two stations were selected in strategic points and sampled at three occasions on Sptember 2014, Junary 2015 and April 2015. Parameters used in this study were a physico-chimical analysis of water (pH, CE, Dissolved O2), sediments (pH, CE, CaCo3, MO) and contamination level of sediments by cadmium, completed by biological testing and analysis of existing benthic community. The results of the physico-chemical parameters show that the water temperature is average and seasonal, the pH value is acidic, does not exceed 6.64. The amplitude variation may be important from upstream to downstream. The generally high electrical conductivity, for the carbonate nature of the watershed increases from upstream to downstream. The waters of the Rhumel wadi are excessively mineralized, dissolved oxygen, a vital factor for benthic community wildlife downstream decreases with increasing organic loading; oxygen is consumed by the microorganisms to its degradation. Analysis of the benthic fauna and calculating the biotic index show a clear excessive pollution for both upstream and downstream stations.

Keywords: biological analysis, benthic fauna, sediments contamination, cadmium

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Authors: Mahmoud Abu-Ghoush, Murad Al Holy

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Our main goal in this project is to study the causes and finding solutions for both the hydrolytic and the oxidative rancidity that can be produced during condensed yoghurt production. The re pasteurization of the pasteurized milk and the addition of different types of antioxidants (ascorbic acid and propyl gallate) were used to achieve this goal. Chemical, physical, microbial and sensory tests were done to evaluate the product. It was found that there were significant differences between the different treatments and the control regarding the peroxide value. This means that the addition of both types of antioxidants have a positive effect in decreasing the rancidity value. However, it was found that there were some samples have hydrolytic rancidity flavour without any type of oxidative rancidity (low peroxide value). To overcome this problem the re pasteurization step was used to destroy all the vegetative form of microbes. It was found that this treatment was very useful in controlling the rancidity flavour according to the sensory evaluation of the condensed yoghurt products for several batches. The best condensed yoghurt which contains 0.25% ascorbic acid exhibited the highest sensory properties values. Also, it has the ability in lowering the oxidative rancidity in the combination with the re pasteurization step of the pasteurized milk. This suggests that a higher quality and stable condensed yoghurt can be obtained upon using this combination. These results may help producers in selecting the best treatment methods to overcome the rancidity flavor in this type of condensed yoghurt.

Keywords: antioxidants, condensed yoghurt, repasturization, condensed milk

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Authors: Ahmet Faruk Akyuz, Hasan Sakir Bilge

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Depth estimation using stereo images is a challenging problem in computer vision. Many different studies have been carried out to solve this problem. With advancing machine learning, tackling this problem is often done with neural network-based solutions. The images used in these studies are mostly in the visible spectrum. However, the need to use the Infrared (IR) spectrum for depth estimation has emerged because it gives better results than visible spectra in some conditions. At this point, we recommend using thermal-thermal (IR) image pairs for depth estimation. In this study, we used two well-known networks (PSMNet, FADNet) with minor modifications to demonstrate the viability of this idea.

Keywords: thermal stereo matching, deep neural networks, CNN, Depth estimation

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Authors: Wing Chi Wong

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Globally, studying parents caring for children with attention deficit/ hyperactivity disorder (ADHD) is valuable in order to design measures in supporting those parents by health care providers and government. Such parents in Hong Kong seem to encounter detrimental stress and enormous difficulties which are exacerbated by the traditional Chinese culture, exclusion from social members and fiercely competitive educational system. However, seldom studies scrutinize this issue in Hong Kong. This article aims to review the literature regarding parents caring offsprings with ADHD in Hong Kong. Criteria were set for searching among published studies listed in various databases, including MEDLINE, CINCAHL, PsycINFO, ProQuest, Embase, Cochrane Library and Springer Link. Articles with words 'Attention Deficit Hyperactivity Disorder', 'parenting', 'parent', 'family', 'father', 'mother', 'care' in titles and abstracts were identified. Articles with all types of research designs and methods, regardless in English or Chinese, were included. They were limited to years between January 2008 and September 2018. Four relevant studies have resulted. Of them, two were exploratory studies, one was a qualitative study, and one was a survey. Samples were recruited from child psychiatric clinic, Child and Adolescent Mental Health Unit, or multiple family group therapy centres. Authors proclaimed that quality of life of those parents was usually low; particularly mothers perceived a higher stress than fathers; parenting barriers existed; conflicts were commonly raised in parent-child relationship resulting in probable maltreatment to children. Previous studies generally suggested the potential negative outcomes of parents caring children with ADHD. The types and effectiveness of interventions to those parents on relieving their tortures under Hong Kong context had not been explored and systematically evaluated. The scanty studies and existing understanding could not give a promising conclusion pertaining to the appropriate family intervention to parents living with children with ADHD. A stringent research design is necessary to establish evidence on the effectiveness of interventions for those families.

Keywords: attention deficit/ hyperactivity disorder, Hong Kong, parents, interventions

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Authors: Mladen Jankovic, Biljana Djuric, Djurdja Oljaca, Vladimir Damjanovic, Radislav Filipovic, Zoran Obrenovic

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One of the key characteristics of zeolites with ZSM-5 crystalline form is the possibility of synthesis in a wide range of molar ratios, from the relatively low ratio of about 20 to highly silicate forms with a Si/Al ratio over 1000. For industrial production and commercial use of this type of zeolite, it is very important to know the influence of the molar Si/Al ratio on the characteristics of zeolite powders. In this paper, the influence of the Si/Al ratio on the characteristics of H-ZSM-5 zeolites synthesized in the presence of tetrapropylammonium bromide is questioned, including the possibility of conversion to the H-form using different acids. The quality of the samples is characterized in terms of crystallinity, chemical composition, morphology, granulometry, specific surface area (BET), pore size and acidity. XRD, FT-IR, EDX, ICP, SEM and TPD instrumental techniques were used to characterize the samples. In most of the performed syntheses, zeolite has been obtained with very good properties. It was shown that the examined conditions have a significant influence on the characteristics of the synthesized powders. The different chemical composition of the starting mixture, ie. the Si/Al ratio, has a very significant influence on the crystal structure of the synthesized powders, and thus on the other tested characteristics. It has been observed that optimal ion exchange results for powders of different Si/Al ratios are achieved by using different acids. Also, the dependence of the specific surface on the concentration of H+ or Na+ ions was confirmed.

Keywords: Characterisation, H-ZSM-5, molar ratio, synthesis, tetrapropylammonium bromide

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Authors: Harshada Vaidya-Kannur, Dattatraya Naik

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Propolis, one of the beehive products also referred as bee-glue is sticky dark coloured complex mixture of compounds. The volatile oil can be isolated from the propolis by hydrodistillation. The mark that is left behind after the removal of volatile oil is referred as the de-oiled propolis. Antioxidant as well as anti-inflammatory properties of total ethanolic extract of de-oiled propolis (TEEDP) was investigated. Another lot of deoiled propolis was successively exacted with hexane, ethyl acetate and ethanol. Activities of these fractions were also determined. Antioxidant activity was determined by studying ABTS, DPPH and NO radical scavenging. Determination of anti-inflammatory activity was carried out by topical TPA induced mouse ear oedema model. It is noteworthy that ethyl acetate fraction of deoiled propolis (EAFDP) exhibited 49.45 % TEAC activity at the concentration 0.2 mg/ml which is equivalent to the activity of trolox at the concentration 0.2 mg/ml. Its DPPH scavenging activity (72.56%) was closely comparable to that of trolox (75%). However its NO scavenging activity was comparatively low. From IC50 values it could be concluded that the efficiency of scavenging ABTS radicals by the de-oiled propolis was more pronounced as compared to scavenging of other radicals. Studies by TPA induced mouse ear inflammation model indicated that the de-oiled propolis of Indian origin had significant topical anti-inflammatory activity. The EAFDP was found to be the most active fraction for this activity also. The purification of EAFP yielded six pure crystalline compounds. These compounds were identified by their physical data and spectral data.

Keywords: anti-inflammatory activity, anti-oxidant activity, column chromatography, de-oiled propolis

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Authors: Oxana Lukoshus

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The methods of corpus linguistics, a well-established field of research, are being increasingly applied in cognitive linguistics. Corpora data are especially useful for different quantitative studies of grammatical and other aspects of language. The main objective of this paper is to demonstrate how present-day corpora can be applied in semantic studies in general and in semantic studies of adjectives in particular. Polysemantic adjectives have been the subject of numerous studies. But most of them have been carried out on dictionaries. Undoubtedly, dictionaries are viewed as one of the basic data sources, but only at the initial steps of a research. The author usually starts with the analysis of the lexicographic data after which s/he comes up with a hypothesis. In the research conducted three polysemantic synonyms true, loyal, faithful have been analyzed in terms of differences and similarities in their semantic structure. A corpus-based approach in the study of the above-mentioned adjectives involves the following. After the analysis of the dictionary data there was the reference to the following corpora to study the distributional patterns of the words under study – the British National Corpus (BNC) and the Corpus of Contemporary American English (COCA). These corpora are continually updated and contain thousands of examples of the words under research which make them a useful and convenient data source. For the purpose of this study there were no special needs regarding genre, mode or time of the texts included in the corpora. Out of the range of possibilities offered by corpus-analysis software (e.g. word lists, statistics of word frequencies, etc.), the most useful tool for the semantic analysis was the extracting a list of co-occurrence for the given search words. Searching by lemmas, e.g. true, true to, and grouping the results by lemmas have proved to be the most efficient corpora feature for the adjectives under the study. Following the search process, the corpora provided a list of co-occurrences, which were then to be analyzed and classified. Not every co-occurrence was relevant for the analysis. For example, the phrases like An enormous sense of responsibility to protect the minds and hearts of the faithful from incursions by the state was perceived to be the basic duty of the church leaders or ‘True,’ said Phoebe, ‘but I'd probably get to be a Union Official immediately were left out as in the first example the faithful is a substantivized adjective and in the second example true is used alone with no other parts of speech. The subsequent analysis of the corpora data gave the grounds for the distribution groups of the adjectives under the study which were then investigated with the help of a semantic experiment. To sum it up, the corpora-based approach has proved to be a powerful, reliable and convenient tool to get the data for the further semantic study.

Keywords: corpora, corpus-based approach, polysemantic adjectives, semantic studies

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Authors: Kalangi Rodrigo

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The term Neuroecology elucidates the study of customizable variation in cognition and the brain. Subject marked the birth since 1980s, when researches began to apply methods of comparative evolutionary biology to cognitive processes and the underlying neural mechanisms of cognition. In Archaeology and Anthropology, we observe behaviors such as social learning skills, innovative feeding and foraging, tool use and social manipulation to determine the cognitive processes of ancient mankind. Depending on the brainstem size was used as a control variable, and phylogeny was controlled using independent contrasts. Both disciplines need to enriched with comparative literature and neurological experimental, behavioral studies among tribal peoples as well as primate groups which will lead the research to a potential end. Neuroecology examines the relations between ecological selection pressure and mankind or sex differences in cognition and the brain. The goal of neuroecology is to understand how natural law acts on perception and its neural apparatus. Furthermore, neuroecology will eventually lead both principal disciplines to Ethology, where human behaviors and social management studies from a biological perspective. It can be either ethnoarchaeological or prehistoric. Archaeology should adopt general approach of neuroecology, phylogenetic comparative methods can be used in the field, and new findings on the cognitive mechanisms and brain structures involved mating systems, social organization, communication and foraging. The contribution of neuroecology to archaeology and anthropology is the information it provides on the selective pressures that have influenced the evolution of cognition and brain structure of the mankind. It will shed a new light to the path of evolutionary studies including behavioral ecology, primate archaeology and cognitive archaeology.

Keywords: Neuroecology, Archaeology, Brain Evolution, Cognitive Archaeology

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Authors: Francesca Gullo, Paola Palmero, Massimo Messori

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Transparent wood is considered a promising structural material for the development of environmentally friendly, energy-efficient engineered components. To obtain transparent wood from natural wood materials two approaches can be used: i) bottom-up and ii) top-down. Through the second method, the color of natural wood samples is lightened through a chemical bleaching process that acts on chromophore groups of lignin, such as the benzene ring, quinonoid, vinyl, phenolics, and carbonyl groups. These chromophoric units form complex conjugate systems responsible for the brown color of wood. There are two strategies to remove color and increase the whiteness of wood: i) lignin removal and ii) lignin bleaching. In the lignin removal strategy, strong chemicals containing chlorine (chlorine, hypochlorite, and chlorine dioxide) and oxidizers (oxygen, ozone, and peroxide) are used to completely destroy and dissolve the lignin. In lignin bleaching methods, a moderate reductive (hydrosulfite) or oxidative (hydrogen peroxide) is commonly used to alter or remove the groups and chromophore systems of lignin, selectively discoloring the lignin while keeping the macrostructure intact. It is, therefore, essential to manipulate nanostructured wood by precisely controlling the nanopores in the cell walls by monitoring both chemical treatments and process conditions, for instance, the treatment time, the concentration of chemical solutions, the pH value, and the temperature. The elimination of wood light scattering is the second step in the fabrication of transparent wood materials, which can be achieved through two-step approaches: i) the polymer impregnation method and ii) the densification method. For the polymer impregnation method, the wood scaffold is treated with polymers having a corresponding refractive index (e.g., PMMA and epoxy resins) under vacuum to obtain the transparent composite material, which can finally be pressed to align the cellulose fibers and reduce interfacial defects in order to have a finished product with high transmittance (>90%) and excellent light-guiding. However, both the solution-based bleaching and the impregnation processes used to produce transparent wood generally consume large amounts of energy and chemicals, including some toxic or pollutant agents, and are difficult to scale up industrially. Here, we report a method to produce optically transparent wood by modifying the lignin structure with a chemical reaction at room temperature using small amounts of hydrogen peroxide in an alkaline environment. This method preserves the lignin, which results only deconjugated and acts as a binder, providing both a strong wood scaffold and suitable porosity for infiltration of biobased polymers while reducing chemical consumption, the toxicity of the reagents used, polluting waste, petroleum by-products, energy and processing time. The resulting transparent wood demonstrates high transmittance and low thermal conductivity. Through the combination of process efficiency and scalability, the obtained materials are promising candidates for application in the field of construction for modern energy-efficient buildings.

Keywords: bleached wood, energy-efficient components, hydrogen peroxide, transparent wood, wood composites

Procedia PDF Downloads 33

Authors: Jeevan Jyoti, Bhanu Pratap Singh, S. R. Dhakate

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In the present study, multiwalled carbon nanotubes (MWCNTs) and reduced graphene oxide (RGO) were synthesized by chemical vapor deposition and Improved Hummer’s method, respectively and their composite with acrylonitrile butadiene styrene (ABS) were prepared by twin screw co rotating extrusion technique. The electromagnetic interference (EMI) shielding effectiveness of graphene oxide carbon nanotube (GCNTs) hybrid composites was investigated and the results were compared with EMI shielding of carbon nanotube (CNTs) and reduced graphene oxide (RGO) in the frequency range of 12.4-18 GHz (Ku-band). The experimental results indicate that the EMI shielding effectiveness of these composites is achieved up to –21 dB for 10 wt. % loading of GCNT loading. The mechanism of improvement in EMI shielding effectiveness is discussed by resolving their contribution in absorption and reflection loss. The main reason for such a high improved shielding effectiveness has been attributed to the significant improvement in the electrical conductivity of the composites. The electrical conductivity of these GCNT/ABS composites was increased from 10-13 S/cm to 10-7 S/cm showing the improvement of the 6 order of the magnitude. Scanning electron microscopic (SEM) and high resolution transmission electron microscopic (HRTEM) studies showed that the GCNTs were uniformly dispersed in the ABS polymer matrix. GCNTs form a network throughout the polymer matrix and promote the reinforcement.

Keywords: ABS, EMI shielding, multiwalled carbon nanotubes, reduced graphene oxide, graphene, oxide-carbon nanotube (GCNTs), twin screw extruder, multiwall carbon nanotube, electrical conductivity

Procedia PDF Downloads 342

Authors: Samadhan S. Nagane, Sachin S. Kuhire, Prakash P. Wadgaonkar

Abstract:

Lignocellulose-derived chemicals such as furfural, furandicarboxylic acid, syringol, guaiacol, etc are highly attractive as sustainable alternatives to petrochemicals for the synthesis of monomers and polymers. We wish to report herein the facile synthesis of fully bio-based bisphenols containing pendant furyl group by base-catalyzed condensation of furfural with guaiacol. Bisphenols possessing pendant furyl group represent valuable monomers for the synthesis of a range of polymers which include epoxy resins, polyesters, polycarbonates, poly(aryl ether)s, etc. Several new homo/co-poly(arylene ether sulfone)s have been prepared by the reaction of 4,4(-fluorodiphenyl sulfone (FDS) with 4,4'-(furan-2-ylmethylene)bis(2-methoxyphenol) (BPF) and 4,4(-isopropylidenediphenol (BPA) using different molar ratios of bisphenols. Poly(arylene ether sulfone)s showed inherent viscosities in the range 0.92-1.47 dLg-1 and number average molecular weights (Mn), obtained from gel permeation chromatography (GPC), were in the range 91,300 – 1,31,000. Poly(arylene ether sulfone)s could be cast into tough, transparent and flexible films from chloroform solutions. X-Ray diffraction studies indicated amorphous nature of poly(arylene ether sulfone)s. Poly(arylene ether sulfone)s showed Tg values in the range 179-191 oC. Additionally, the pendant furyl groups in poly(arylene ether sulfone)s provide reactive sites for chemical modifications and cross-linking via Diels-Alder reaction with maleimides and bismaleimides, respectively.

Keywords: bio-based, bisphenols, Diels-Alder reaction, poly(arylene ether sulfone)s

Procedia PDF Downloads 240

Authors: Nounamo Nguedie Yann Harold

Abstract:

The factors behind the debt have been the subject of several studies in the literature. Pioneering studies based on the 'double deficit' approach linked indebtedness to the imbalance between savings and investment, the budget deficit and the current account deficit. Most studies on identifying factors that may stimulate or reduce the level of external public debt agree that the following variables are important explanatory variables in leveraging debt: the budget deficit, trade opening, current account and exchange rate, import, export, interest rate, term variation exchange rate, economic growth rate and debt service, capital flight, and over-indebtedness. Few studies addressed the impact of political factors on the level of external debt. In general, however, the IMF's stabilization programs in developing countries following the debt crisis have resulted in economic recession and the advent of political crises that have resulted in changes in governments. In this sense, political institutions are recognised as factors of accumulation of external debt in most developing countries. This paper assesses the role of political factors on the external debt level of African countries in the Franc Zone over the period 1985-2016. Data used come from World Bank and ICRG. Using a logit in panel, the results show that the more a country is politically stable, the lower the external debt compared to the gross domestic product. Political stability multiplies 1.18% the chances of being in the sustainable debt zone. For example, countries with good political institutions experience less severe external debt burdens than countries with bad political institutions.

Keywords: African countries, external debt, Franc Zone, political factors

Procedia PDF Downloads 198

Authors: S. Muthuraja Soundrapandian, C.K. Subramaniam

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A micro Direct Methanol Fuel Cell (DMFC) of 1 cm2 active area with selective sensor materials to sense methanol for redox, has been developed. Among different Pt alloys, Pt-Sn/C was able to produce high current density and repeatability. Membrane Elecctrode Assembly (MEA) of anode catalyst Pt-Sn/C was prepared with nafion as active membrane and Pt black as cathode catalyst. The sensor’s maximum ability to detect the trace levels of methanol in ppm has been analyzed. A compact sensor set up has also been made and the characterization studies were carried out. The acceptable value of current density was derived by the cell and the results are able to fulfill the needs of DMFC technology for the practical applications.

Keywords: DMFC, sensor, MEA, Pt-Sn

Procedia PDF Downloads 121

Authors: Merzak Siham, Benguerine Zohra, Si Tayeb Fatima, Bouzian Chaimaa Affaf, Jou Siham, Belkessam Nafissa

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Introduction: Medicinal plants, particularly spices, are essential for pharmacological research due to their health benefits. This study focuses on Curcuma longa, a spice recognized for its therapeutic properties. Materials and Methods: This study is based on a thorough search conducted on Google Scholar, PubMed, and ScienceDirect. From an initial selection of 25 articles, five were chosen to extract relevant information on Curcuma longa. Results and Discussions: Clinical studies have indicated that curcumin is well tolerated at doses up to 12 g/day. Its anti-rheumatic efficacy was compared to phenylbutazone in 18 individuals. Each participant received a daily dose of either 1200 mg of curcumin or 300 mg of phenylbutazone for 2 weeks. Curcumin was well tolerated at this dose and demonstrated activity comparable to phenylbutazone. Additionally, a study on 62 patients showed that curcumin sustainably relieved symptoms without toxicity. Its effects included reduced itching, lesions, and pain. In ten volunteers, administering 500 mg of curcumin for seven days resulted in a 33% decrease in lipid peroxidation, a 29% increase in HDL cholesterol, and a 12% decrease in total cholesterol. It is important to note that curcumin is a potent, selective inhibitor of phosphorylase kinase, an increased marker in psoriasis. Conclusion: Curcumin is promising as a future drug for various diseases, but its bioavailability must be improved through techniques such as nano encapsulation. Additionally, exploring chemical derivatives of curcumin could lead to more potent and targeted molecules.

Keywords: turmeric, spice, medicinal plants, pharmacological activities.

Procedia PDF Downloads 14

Authors: Udayakumar Vee, Franck Quero

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Zwitterionic polymers generally have been viewed as a new class of antimicrobial and non-fouling materials. They offer a broad versatility for chemical modification and hence great freedom for accurate molecular design, which bear an equimolar number of homogenously distributed anionic and cationic groups along their polymer chains. This study explores the effectiveness of the auxetic zwitterion carboxylate/sulfonate hydrogel in the diabetic-induced mouse model. A series of silver metal-doped auxetic zwitterion carboxylate/sulfonate/vinylaniline copolymer hydrogels is designed via a 3D printer. Zwitterion monomers have been characterized by FT-IR and NMR techniques. The effect of changing the monomers and different loading ratios of Ag over zwitterion on the final hydrogel materials' antimicrobial properties and biocompatibility will be investigated in detail. The synthesized auxetic hydrogel has been characterized using a wide range of techniques to help establish the relationship between molecular level and macroscopic properties of these materials, including mechanical and antibacterial and biocompatibility and wound healing ability. This work's comparative studies and results provide new insights and guide us in choosing a better auxetic structured material for a broad spectrum of wound healing applications in the animal model. We expect this approach to provide a versatile and robust platform for biomaterial design that could lead to promising treatments for wound healing applications.

Keywords: auxetic, zwitterion, carboxylate, sulfonate, polymer, wound healing

Procedia PDF Downloads 120

Authors: Ahmed Borg, Elsa Aristodemou, Attia Attia

Abstract:

Well control involves managing the circulating drilling fluid within the wells and avoiding kicks and blowouts as these can lead to losses in human life and drilling facilities. Current practices for good control incorporate predictions of pressure losses through computational models. Developing a realistic hydraulic model for a good control problem is a very complicated process due to the existence of a complex multiphase region, which usually contains a non-Newtonian drilling fluid and the miscibility of formation gas in drilling fluid. The current approaches assume an inaccurate flow fluid model within the well, which leads to incorrect pressure loss calculations. To overcome this problem, researchers have been considering the more complex two-phase fluid flow models. However, even these more sophisticated two-phase models are unsuitable for applications where pressure dynamics are important, such as in managed pressure drilling. This study aims to develop and implement new fluid flow models that take into consideration the miscibility of fluids as well as their non-Newtonian properties for enabling realistic kick treatment. furthermore, a corresponding numerical solution method is built with an enriched data bank. The research work considers and implements models that take into consideration the effect of two phases in kick treatment for well control in conventional drilling. In this work, a corresponding numerical solution method is built with an enriched data bank. Software STARCCM+ for the computational studies to study the important parameters to describe wellbore multiphase flow, the mass flow rate, volumetric fraction, and velocity of each phase. Results showed that based on the analysis of these simulation studies, a coarser full-scale model of the wellbore, including chemical modeling established. The focus of the investigations was put on the near drill bit section. This inflow area shows certain characteristics that are dominated by the inflow conditions of the gas as well as by the configuration of the mud stream entering the annulus. Without considering the gas solubility effect, the bottom hole pressure could be underestimated by 4.2%, while the bottom hole temperature is overestimated by 3.2%. and without considering the heat transfer effect, the bottom hole pressure could be overestimated by 11.4% under steady flow conditions. Besides, larger reservoir pressure leads to a larger gas fraction in the wellbore. However, reservoir pressure has a minor effect on the steady wellbore temperature. Also as choke pressure increases, less gas will exist in the annulus in the form of free gas.

Keywords: multiphase flow, well- control, STARCCM+, petroleum engineering and gas technology, computational fluid dynamic

Procedia PDF Downloads 101

Authors: Jin A Ryu, Hee Sun Kim

Abstract:

As the number of fire accidents is gradually raising, many studies have been reported on evacuation. Previous studies have mostly focused on evaluating the safety of evacuation and the risk of fire in particular buildings. However, studies on effects of various parameters on evacuation have not been nearly done. Therefore, this paper aims at observing evacuation time under the effect of fire initiated location. In this study, evacuation simulations are performed on a 5-floor building located in Seoul, South Korea using the commercial program, Fire Dynamics Simulator with Evacuation (FDS+EVAC). Only the fourth and fifth floors are modeled with an assumption that fire starts in a room located on the fourth floor. The parameter for evacuation simulations is location of fire initiation to observe the evacuation time and safety. Results show that the location of fire initiation is closer to exit, the more time is taken to evacuate. The case having the nearest location of fire initiation to exit has the lowest ratio of successful occupants to the total occupants. In addition, for safety evaluation, the evacuation time calculated from computer simulation model is compared with the tolerable evacuation time according to code in Japan. As a result, all cases are completed within the tolerable evacuation time. This study allows predicting evacuation time under various conditions of fire and can be used to evaluate evacuation appropriateness and fire safety of building.

Keywords: fire simulation, evacuation simulation, temperature, evacuation safety

Procedia PDF Downloads 325

Authors: Udayakumar Veerabagu, Franck Quero

Abstract:

Zwitterion carboxylate and sulfonate polymers generally have been viewed as a new class of antimicrobial and non-fouling materials. They offer a broad versatility for chemical modification and hence great freedom for accurate molecular design, which bear an equimolar number of homogenously distributed anionic and cationic groups along their polymer chains. This study explores the effectiveness of the auxetic zwitterion carboxylate/sulfonate hydrogel in the diabetic-induced mouse model. A series of silver metal-doped auxetic zwitterion carboxylate/sulfonate/vinylaniline copolymer hydrogels is designed via a 3D printer. Zwitterion monomers have been characterized by FT-IR and NMR techniques. The effect of changing the monomers and different loading ratios of Ag over zwitterion on the final hydrogel materials' antimicrobial properties and biocompatibility will be investigated in detail. The synthesized auxetic hydrogel has been characterized using a wide range of techniques to help establish the relationship between molecular level and macroscopic properties of these materials, including mechanical and antibacterial and biocompatibility and wound healing ability. This work's comparative studies and results provide new insights and guide us in choosing a better auxetic structured material for a broad spectrum of wound healing applications in the animal model. We expect this approach to provide a versatile and robust platform for biomaterial design that could lead to promising treatments for wound healing applications.

Keywords: auxetic, zwitterion, carboxylate, sulfonate, polymer, wound healing

Procedia PDF Downloads 134