Search results for: hydrothermal synthesis
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 2249

Search results for: hydrothermal synthesis

1499 Highly-Efficient Photoreaction Using Microfluidic Device

Authors: Shigenori Togashi, Yukako Asano

Abstract:

We developed an effective microfluidic device for photoreactions with low reflectance and good heat conductance. The performance of this microfluidic device was tested by carrying out a photoreactive synthesis of benzopinacol and acetone from benzophenone and 2-propanol. The yield reached 36% with an irradiation time of 469.2 s and was improved by more than 30% when compared to the values obtained by the batch method. Therefore, the microfluidic device was found to be effective for improving the yields of photoreactions.

Keywords: microfluidic device, photoreaction, black aluminum oxide, benzophenone, yield improvement

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1498 Synthesis and Gas Transport Properties of Polynorbornene Dicarboximides Bearing Trifluoromethyl Isomer Moieties

Authors: Jorge A. Cruz-Morales, Joel Vargas, Arlette A. Santiago, Mikhail A. Tlenkopatchev

Abstract:

In industrial processes such as oil extraction and refining, products are handled or generated in the gas phase, which represents a challenge in terms of treatment and purification. During the past three decades, new scientific findings and technological advances in separation based on the use of membranes have led to simpler and more efficient gas separation processes, optimizing the use of energy and generating less pollution. This work reports the synthesis and ring-opening metathesis polymerization (ROMP) of new structural isomers based on norbornene dicarboximides bearing trifluoromethyl moieties, specifically N-2-trifluoromethylphenyl-exo,endo-norbornene-5,6-dicarboximide (2a) and N-3-trifluoromethylphenyl-exo,endo-norbornene-5,6-dicarboximide (2b), using tricyclohexylphosphine [1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene][benzylidene] ruthenium dichloride (I), bis(tricyclohexylphosphine) benzylidene ruthenium (IV) dichloride (II), and bis(tricyclohexylphosphine) p-fluorophenylvinylidene ruthenium (II) dichloride (III). It was observed that the -CF3 moiety attached at the ortho position of the aromatic ring increases thermal and mechanical properties of the polymer, whereas meta substitution has the opposite effect. A comparative study of gas transportation in membranes, based on these fluorinated polynorbornenes, showed that -CF3 ortho substitution increases permeability of the polymer membrane as a consequence of the increase in both gas solubility and gas diffusion. In contrast, gas permeability coefficients of the meta-substituted polymer membrane are rather similar to those of that which is non-fluorinated; this can be attributed to a lower fractional free volume. The meta-substituted polymer membrane, besides showing the largest permselectivity coefficients of all the isomers studied here, was also found to have one of the largest permselectivity coefficients for separating H2/C3H6 into glassy polynorbornene dicarboximides.

Keywords: gas transport membranes, polynorbornene dicarboximide, ROMP, structural isomers

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1497 Antibiofilm Activities of Biogenic Silver Nanoparticles against Human Pathogenic Bacteria

Authors: Muhammad Shahzad Tufail, Iram Liaqat, Umer Sohail Meer, Muhammad Ishtaiq, Muhammad Sattar

Abstract:

Nanotechnology is a vibrant field with numerous applications in many different branches of science and technology. Several methods are used to synthesize nanoparticles (NPs), which have multiple range of applications. Comparatively, the biogenic synthesis of NPs is a more economical and environmentally favourable method than the traditional chemical method. The current study aims to synthesize biogenically silver nanoparticles (AgNPs) using bacterial isolates. Four bacterial strains Escherichia coli (MT448673), Pseudomonas aeruginosa (MN900691), Bacillus subtilis (MN900684) and Bacillus licheniformis (MN900686) were used for the synthesis of AgNPs from silver nitrate (AgNO3) solution. The biofilm time kinetics of four bacterial isolates (P. aeruginosa, E. coli, B. licheniformis and B. subtilis) was analysed by incubating bacterial cultures at 37◦C in test tubes over a period of different time intervals i.e., 2, 3, 5 and 7 days following crystal violet staining method. All the four strains had ability to form strong biofilms between 48 to 72 hours of incubation. Two strains (B. subtilis and B. licheniformis) formed significant (p < 0.05) biofilm after 3 days of incubation period. The other two strains (E. coli and P. aeruginosa) showed strong biofilm formation after 2 days of incubation. Next, the antibiofilm activity of biogenically synthesized AgNPs (10 - 100 µgmL-1) was analysed against biofilm forming human pathogenic bacteria. Findings of the work revealed that 60-90% inhibition was observed at 60 µgmL-1 of AgNPs, while maximum inhibition (i.e.,100%) was found at highest concentration (90 µgmL-1). It was evident that highly significant (p < 0.05) decrease in biofilm formation was observed with increasing concentration of AgNPs.

Keywords: antibiofilm, biofilm formation, nanotechnology, pathogenic bacteria, silver nanoparticles

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1496 The Relationship between Size of Normal and Cystic Bovine Ovarian Follicles with Follicular Fluid Levels of Nitric Oxide and Estradiol

Authors: Hamidreza Khodaei, Behnaz Mahdavi, Leila Karshenas

Abstract:

Nitric oxide (NO) is a small fast acting neurotransmitter, which is synthesized From L-arginine by nitric oxide synthase. Studies show that NO affects a wide range of reproductive functions. Steroidal hormones synthesis, LH surge during ovulation, follicular growth and ovulation are all affected by NO. Therefore, the objective of this study was to evaluate the relationship between NO and estradiol (E2) production in ovarian follicles and cysts in bovines. Two experiment groups were formed and serum and follicular fluid levels Of NO and estradiol (E2) was measured. In the first group, follicular fluids were obtained from 30 slaughtered cows. Follicles were divided into three groups according to follicular diameter: Small follicles, <5 mm, medium-sized follicles, 5 to 10 mm, and large follicles, >10 mm. 30 follicles were randomly selected within each group. Blood samples were obtained via jugular vein. NO concentrations in blood and ovarian follicular fluids were measured by Griess reaction method and radio-immunoassay respectively. In the second group: 12 cows in follicular phase and with cystic follicles were selected and a cystic follicle was obtained from each. NO and E2 levels were measured as done for the first experiment group. The data were analyzed by SAS software using ANOVA and Duncan’s test. NO concentrations of follicular fluids from large follicles were significantly higher than those of the medium and small-sized ones. There were significant differences in the concentrations of nitrite and nitrate (Stable metabolites of NO) between large and cystic follicles, with extremely low NO and high E2 levels in cystic follicles (p<0.01).The results suggest that paracrine effects of NO may play an important role in the control of ovarian follicle growth and development of cystic follicles in bovines. It seems that NO dictates its effects through inhibition of ovarian steroidal synthesis.

Keywords: nitric oxide, estradiol, cystic follicle, cow, oogenesis, oocyte maturation, follicular fluid

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1495 From Homogeneous to Phase Separated UV-Cured Interpenetrating Polymer Networks: Influence of the System Composition on Properties and Microstructure

Authors: Caroline Rocco, Feyza Karasu, Céline Croutxé-Barghorn, Xavier Allonas, Maxime Lecompère, Gérard Riess, Yujing Zhang, Catarina Esteves, Leendert van der Ven, Rolf van Benthem Gijsbertus de With

Abstract:

Acrylates are widely used in UV-curing technology. Their high reactivity can, however, limit their conversion due to early vitrification. In addition, the free radical photopolymerization is known to be sensitive to oxygen inhibition leading to tacky surfaces. Although epoxides can lead to full polymerization, they are sensitive to humidity and exhibit low polymerization rate. To overcome the intrinsic limitations of both classes of monomers, Interpenetrating Polymer Networks (IPNs) can be synthesized. They consist of at least two cross linked polymers which are permanently entangled. They can be achieved under thermal and/or light induced polymerization in one or two steps approach. IPNs can display homogeneous to heterogeneous morphologies with various degrees of phase separation strongly linked to the monomer miscibility and also synthesis parameters. In this presentation, we synthesize UV-cured methacrylate - epoxide based IPNs with different chemical compositions in order to get a better understanding of their formation and phase separation. Miscibility before and during the photopolymerization, reaction kinetics, as well as mechanical properties and morphology have been investigated. The key parameters controlling the morphology and the phase separation, namely monomer miscibility and synthesis parameters have been identified. By monitoring the stiffness changes on the film surface, atomic force acoustic microscopy (AFAM) gave, in conjunction with polymerization kinetic profiles and thermomechanical properties, explanations and corroborated the miscibility predictions. When varying the methacrylate / epoxide ratio, it was possible to move from a miscible and highly-interpenetrated IPN to a totally immiscible and phase-separated one.

Keywords: investigation of properties and morphology, kinetics, phase separation, UV-cured IPNs

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1494 Investigating the Flavin-Dependent Thymidylate Synthase (FDTS) Enzyme from Clostridioides Difficile (C. diff)

Authors: Sidra Shaw, Sarenna Shaw, Chae Joon Lee, Irimpan Mathews, Eric Koehn

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One of the biggest public health concerns of our time is increasing antimicrobial resistance. As of 2019, the CDC has documented more than 2.8 million serious antibiotic resistant infections in the United States. Currently, antibiotic resistant infections are directly implicated in over 750,000 deaths per year globally. On our current trajectory, British economist Jim O’Neill predicts that by 2050, an additional 10 million people (about half the population of New York) will die annually due to drug resistant infections. As a result, new biochemical pathways must be targeted to generate next generation antibiotic drugs that will be effective against drug resistant bacteria. One enticing target is the biosynthesis of DNA within bacteria, as few drugs interrupt this essential life process. Thymidylate synthase enzymes are essential for life as they catalyze the synthesis of a DNA building block, 2′-deoxythymidine-5′-monophosphate (dTMP). In humans, the thymidylate synthase enzyme (TSase) has been shown to be distinct from the flavin-dependent thymidylate synthase (FDTS) produced by many pathogenic bacteria. TSase and FDTS have distinct structures and mechanisms of catalysis, which should allow selective inhibition of FDTS over human TSase. Currently, C. diff is one of the most antibiotic resistant bacteria, and no drugs that target thymine biosynthesis exist for C. diff. Here we present the initial biochemical characterization of FDTS from C. diff. Specifically, we examine enzyme kinetics and binding features of this enzyme to determine the nature of interaction with ligands/inhibitors and understand the molecular mechanism of catalysis. This research will provide more insight into the targetability of the C. diff FDTS enzyme for novel antibiotic drugs.

Keywords: flavin-dependent thymidylate synthase, FDTS, clostridioides difficile, C. diff, antibiotic resistance, DNA synthesis, enzyme kinetics, binding features

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1493 Kaolinite-Assisted Microencapsulation of Octodecane for Thermal Energy Storage

Authors: Ting Pan, Jiacheng Wang, Pengcheng Lin, Ying Chen, Songping Mo

Abstract:

Phase change materials (PCMs) are widely used in latent heat thermal energy storage because of their good properties such as high energy storage density and constant heat-storage/release temperature. Microencapsulation techniques can prevent PCMs from leaking during the liquid-solid phase transition and enhance thermal properties. This technique has been widely applied in architectural materials, thermo-regulated textiles, aerospace fields, etc. One of the most important processes during the synthesis of microcapsules is to form a stable emulsion of the PCM core and reactant solution for the formation of the shell of the microcapsules. The use of surfactants is usually necessary for the formation of a stable emulsion system because of the difference in hydrophilia/lipophilicity of the PCM and the solvent. Unfortunately, the use of surfactants may cause pollution to the environment. In this study, modified kaolinite was used as an emulsion stabilizer for the microencapsulation of octodecane as PCM. Microcapsules were synthesized by phase inversion emulsification method, and the shell of polymethyl methacrylate (PMMA) was formed through free radical polymerization. The morphologies, crystalloid phase, and crystallization properties of microcapsules were investigated using scanning electron microscopy (SEM), X-ray diffractometer (XRD), and Fourier transforms infrared spectrometer (FTIR). The thermal properties and thermal stability were investigated by a differential scanning calorimeter (DSC) and a thermogravimetric analyzer (TG). The FT-IR, XRD results showed that the octodecane was well encapsulated in the PMMA shell. The SEM results showed that the microcapsules were spheres with an average size of about 50-100nm. The DSC results indicated that the latent heat of the microcapsules was 152.64kJ/kg and 164.23kJ/kg. The TG results confirmed that the microcapsules had good thermal stability due to the PMMA shell. Based on the results, it can be concluded that the modified kaolinite can be used as an emulsifier for the synthesis of PCM microcapsules, which is valid for reducing part of the possible pollution caused by the utilization of surfactants.

Keywords: kaolinite, microencapsulation, PCM, thermal energy storage

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1492 The Preparation of Titanate Nano-Materials Removing Efficiently Cs-137 from Waste Water in Nuclear Power Plants

Authors: Liu De-jun, Fu Jing, Zhang Rong, Luo Tian, Ma Ning

Abstract:

Cs-137, the radioactive fission products of uranium, can be easily dissolved in water during the accident of nuclear power plant, such as Chernobyl, Three Mile Island, Fukushima accidents. The concentration of Cs in the groundwater around the nuclear power plant exceeded the standard value almost 10,000 times after the Fukushima accident. The adsorption capacity of Titanate nano-materials for radioactive cation (Cs+) is very strong. Moreover, the radioactive ion can be tightly contained in the nanotubes or nanofibers without reversible adsorption, and it can safely be fixed. In addition, the nano-material has good chemical stability, thermal stability and mechanical stability to minimize the environmental impact of nuclear waste and waste volume. The preparation of titanate nanotubes or nanofibers was studied by hydrothermal methods, and chemical kinetics of removal of Cs by nano-materials was obtained. The adsorption time with maximum adsorption capacity and the effects of pH, coexisting ion concentration and the optimum adsorption conditions on the removal of Cs by titanate nano-materials were also obtained. The adsorption boundary curves, adsorption isotherm and the maximum adsorption capacity of Cs-137 as tracer on the nano-materials were studied in the research. The experimental results showed that the removal rate of Cs-137 in 0.01 tons of waste water with only 1 gram nano-materials could reach above 98%, according to the optimum adsorption conditions.

Keywords: preparation, titanate, cs-137, removal, nuclear

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1491 Green Synthesis of Silver Nanoparticles Mediated by Plant by-Product Extracts

Authors: Cristian Moisa, Andreea Lupitu, Adriana Csakvari, Dana G. Radu, Leonard Marian Olariu, Georgeta Pop, Dorina Chambre, Lucian Copolovici, Dana Copolovici

Abstract:

Green synthesis of nanoparticles (NPs) represents a promising, accessible, eco-friendly, and safe process with significant applications in biotechnology, pharmaceutical sciences, and farming. The aim of our study was to obtain silver nanoparticles, using plant wastes extracts resulted in the essential oils extraction process: Thymus vulgaris L., Origanum vulgare L., Lavandula angustifolia L., and in hemp processing for seed and fibre, Cannabis sativa. Firstly, we obtained aqueous extracts of thyme, oregano, lavender, and hemp (two monoicous and one dioicous varieties), all harvested in western part of Romania. Then, we determined the chemical composition of the extracts by liquid-chromatography coupled with diode array and mass spectrometer detectors. The compounds identified in the extracts were in agreement with earlier published data, and the determination of the antioxidant activity of the obtained extracts by DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) assays confirmed their antioxidant activity due to their total polyphenolic content evaluated by Folin-Ciocalteu assay. Then, the silver nanoparticles (AgNPs) were successfully biosynthesised, as was demonstrated by UV-VIS, FT-IR spectroscopies, and SEM, by reacting AgNO₃ solution and plant extracts. AgNPs were spherical in shape, with less than 30 nm in diameter, and had a good bactericidal activity against Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas fluorescens).

Keywords: plant wastes extracts, chemical composition, high performance liquid chromatography mass spectrometer, HPLC-MS, scanning electron microscopy, SEM, silver nanoparticles

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1490 Preparation and Characterization of Iron/Titanium-Pillared Clays

Authors: Rezala Houria, Valverde Jose Luis, Romero Amaya, Molinari Alessandra, Maldotti Andrea

Abstract:

The escalation of oil prices in 1973 confronted the oil industry with the problem of how to maximize the processing of crude oil, especially the heavy fractions, to give gasoline components. Strong impetus was thus given to the development of catalysts with relatively large pore sizes, which were able to deal with larger molecules than the existing molecular sieves, and with good thermal and hydrothermal stability. The oil embargo in 1973 therefore acted as a stimulus for the investigation and development of pillared clays. Iron doped titania-pillared montmorillonite clays was prepared using bentonite from deposits of Maghnia in western-Algeria. The preparation method consists of differents steps (purification of the raw bentonite, preparation of a pillaring agent solution and exchange of the cations located between the clay layers with the previously formed iron/titanium solution). The characterization of this material was carried out by X-ray fluorescence spectrometry, X-ray diffraction, textural measures by BET method, inductively coupled plasma atomic emission spectroscopy, diffuse reflectance UV visible spectroscopy, temperature- programmed desorption of ammonia and atomic absorption.This new material was investigated as photocatalyst for selective oxygenation of the liquid alkylaromatics such as: toluene, paraxylene and orthoxylene and the photocatalytic properties of it were compared with those of the titanium-pillared clays.

Keywords: iron doping, montmorillonite clays, pillared clays, oil industry

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1489 Physico-Chemical Parameters and Economic Evaluation of Bio-Ethanol Produced from Waste of Starting Dates in South Algeria

Authors: Insaf Mehani, Bachir Bouchekima

Abstract:

The fight against climate change and the replacement of fossil energies nearing exhaustion gradually emerge as major societal and economic challenges. It is possible to develop common dates of low commercial value, and put on the local and international market a new generation of products with high added values such as bio ethanol. Besides its use in chemical synthesis, bio ethanol can be blended with gasoline to produce a clean fuel while improving the octane.

Keywords: bio-energy, waste dates, bio ethanol, Algeria

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1488 Development and Investigation of Efficient Substrate Feeding and Dissolved Oxygen Control Algorithms for Scale-Up of Recombinant E. coli Cultivation Process

Authors: Vytautas Galvanauskas, Rimvydas Simutis, Donatas Levisauskas, Vykantas Grincas, Renaldas Urniezius

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The paper deals with model-based development and implementation of efficient control strategies for recombinant protein synthesis in fed-batch E.coli cultivation processes. Based on experimental data, a kinetic dynamic model for cultivation process was developed. This model was used to determine substrate feeding strategies during the cultivation. The proposed feeding strategy consists of two phases – biomass growth phase and recombinant protein production phase. In the first process phase, substrate-limited process is recommended when the specific growth rate of biomass is about 90-95% of its maximum value. This ensures reduction of glucose concentration in the medium, improves process repeatability, reduces the development of secondary metabolites and other unwanted by-products. The substrate limitation can be enhanced to satisfy restriction on maximum oxygen transfer rate in the bioreactor and to guarantee necessary dissolved carbon dioxide concentration in culture media. In the recombinant protein production phase, the level of substrate limitation and specific growth rate are selected within the range to enable optimal target protein synthesis rate. To account for complex process dynamics, to efficiently exploit the oxygen transfer capability of the bioreactor, and to maintain the required dissolved oxygen concentration, adaptive control algorithms for dissolved oxygen control have been proposed. The developed model-based control strategies are useful in scale-up of cultivation processes and accelerate implementation of innovative biotechnological processes for industrial applications.

Keywords: adaptive algorithms, model-based control, recombinant E. coli, scale-up of bioprocesses

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1487 Bioinspired Green Synthesis of Magnetite Nanoparticles Using Room-Temperature Co-Precipitation: A Study of the Effect of Amine Additives on Particle Morphology in Fluidic Systems

Authors: Laura Norfolk, Georgina Zimbitas, Jan Sefcik, Sarah Staniland

Abstract:

Magnetite nanoparticles (MNP) have been an area of increasing research interest due to their extensive applications in industry, such as in carbon capture, water purification, and crucially, the biomedical industry. The use of MNP in the biomedical industry is rising, with studies on their effect as Magnetic resonance imaging contrast agents, drug delivery systems, and as hyperthermic cancer treatments becoming prevalent in the nanomaterial research community. Particles used for biomedical purposes must meet stringent criteria; the particles must have consistent shape and size between particles. Variation between particle morphology can drastically alter the effective surface area of the material, making it difficult to correctly dose particles that are not homogeneous. Particles of defined shape such as octahedral and cubic have been shown to outperform irregular shaped particles in some applications, leading to the need to synthesize particles of defined shape. In nature, highly homogeneous MNP are found within magnetotactic bacteria, a unique bacteria capable of producing magnetite nanoparticles internally under ambient conditions. Biomineralisation proteins control the properties of the MNPs, enhancing their homogeneity. One of these proteins, Mms6, has been successfully isolated and used in vitro as an additive in room-temperature co-precipitation reactions (RTCP) to produce particles of defined mono-dispersed size & morphology. When considering future industrial scale-up it is crucial to consider the costs and feasibility of an additive, as an additive that is not readily available or easily synthesized at a competitive price will not be sustainable. As such, additives selected for this research are inspired by the functional groups of biomineralisation proteins, but cost-effective, environmentally friendly, and compatible with scale-up. Diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and pentaethylenehexamine (PEHA) have been successfully used in RTCP to modulate the properties of particles synthesized, leading to the formation of octahedral nanoparticles with no use of organic solvents, heating, or toxic precursors. By extending this principle to a fluidic system, ongoing research will reveal whether the amine additives can also exert morphological control in an environment which is suited toward higher particle yield. Two fluidic systems have been employed; a peristaltic turbulent flow mixing system suitable for the rapid production of MNP, and a macrofluidic system for the synthesis of tailored nanomaterials under a laminar flow regime. The presence of the amine additives in the turbulent flow system in initial results appears to offer similar morphological control as observed under RTCP conditions, with higher proportions of octahedral particles formed. This is a proof of concept which may pave the way to green synthesis of tailored MNP on an industrial scale. Mms6 and amine additives have been used in the macrofluidic system, with Mms6 allowing magnetite to be synthesized at unfavourable ferric ratios, but no longer influencing particle size. This suggests this synthetic technique while still benefiting from the addition of additives, may not allow additives to fully influence the particles formed due to the faster timescale of reaction. The amine additives have been tested at various concentrations, the results of which will be discussed in this paper.

Keywords: bioinspired, green synthesis, fluidic, magnetite, morphological control, scale-up

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1486 Assessment of Microbiological Feed Safety from Serbian Market from 2013 to 2017

Authors: Danijela Vuković, Radovan Čobanović, Milorad Plačkić

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The expansion of population imposes increase in usage of animal meat, on whose quality directly affects the quality of the feed that the animals are fed with. The selection of raw materials, hygiene during the technological process, various hydrothermal treatments, methods of mixing etc. have an influence on the quality of feed. Monitoring of the feed is very important to obtain information about the quality of feed and the possible prevention of animal diseases which can lead to different human diseases outbreaks. In this study parameters of feed safety were monitored. According to the mentioned, the goal of this study was to evaluate microbiological safety of feed (feedstuffs and complete mixtures). Total number of analyzed samples was 4399. Analyzed feed samples were collected in various retail shops and feed factories during the period of 44 months (from January 2013 untill September 2017). Samples were analyzed on Salmonella spp. and Clostridium perfringens in quantity of 50g according to Serbian regulation. All microorganisms were tested according to ISO methodology: Salmonella spp. ISO 6579:2002 and Clostridium perfringens ISO 7937:2004. Out of 4399 analyzed feed samples 97,5% were satisfactory and 2,5% unsatisfactory concerning Salmonella spp. As far as Clostridium perfringens is concerned 100% of analyzed samples were satisfactory. The obtained results suggest that technological processing of feed in Serbia is at high level when it comes to safety and hygiene of the products, but there are still possibilities for progress and improvement which only can be reached trough the permanent monitoring of feed.

Keywords: microbiology, safety, hygiene, feed

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1485 Applicability of Linearized Model of Synchronous Generator for Power System Stability Analysis

Authors: J. Ritonja, B. Grcar

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For the synchronous generator simulation and analysis and for the power system stabilizer design and synthesis a mathematical model of synchronous generator is needed. The model has to accurately describe dynamics of oscillations, while at the same time has to be transparent enough for an analysis and sufficiently simplified for design of control system. To study the oscillations of the synchronous generator against to the rest of the power system, the model of the synchronous machine connected to an infinite bus through a transmission line having resistance and inductance is needed. In this paper, the linearized reduced order dynamic model of the synchronous generator connected to the infinite bus is presented and analysed in details. This model accurately describes dynamics of the synchronous generator only in a small vicinity of an equilibrium state. With the digression from the selected equilibrium point the accuracy of this model is decreasing considerably. In this paper, the equations’ descriptions and the parameters’ determinations for the linearized reduced order mathematical model of the synchronous generator are explained and summarized and represent the useful origin for works in the areas of synchronous generators’ dynamic behaviour analysis and synchronous generator’s control systems design and synthesis. The main contribution of this paper represents the detailed analysis of the accuracy of the linearized reduced order dynamic model in the entire synchronous generator’s operating range. Borders of the areas where the linearized reduced order mathematical model represents accurate description of the synchronous generator’s dynamics are determined with the systemic numerical analysis. The thorough eigenvalue analysis of the linearized models in the entire operating range is performed. In the paper, the parameters of the linearized reduced order dynamic model of the laboratory salient poles synchronous generator were determined and used for the analysis. The theoretical conclusions were confirmed with the agreement of experimental and simulation results.

Keywords: eigenvalue analysis, mathematical model, power system stability, synchronous generator

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1484 Existential Suffering in the Daily Lives of Those Living with Palliative Care Needs Arising from Chronic Obstructive Pulmonary Disease

Authors: Louise Elizabeth Bolton

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Statement of the problem: There are an estimated 328 million cases of COPD worldwide. It is likely to become the third biggest cause of death by 2030. The impact of living with palliative care needs arising from COPD disrupts an individual’s existential situation. Understandings of individuals' existential situations within COPD are limited within the research literature and are rarely addressed within clinical practice, yet existential suffering has been linked to poor health-related quality of life for those living with other chronic conditions. The purpose of this integrative review is to provide a synthesis of existing evidence on existential suffering for those living with palliative care needs arising from COPD. Methods: This is an integrative review undertaken in accordance with PRISMA guidelines. Nine electronic databases were searched from April 2019 to January 2021. Thirty-five empirical research papers of both qualitative and quantitative methodologies, alongside systematic literature reviews, were included. Data analysis was undertaken using an integrative thematic analysis approach. Findings: Identified themes of existential suffering when living with palliative care needs arising from COPD are as follows: Liminality, Lamented Life, Loss of Personal Liberty, Life Meaning and Existential isolation. The absence of life meaning and purpose was of most importance to patients. Conclusion and Significance: This integrative review provides a synthesis of international evidence upon the presence of existential suffering. It is present and of significant impact within the daily lives of those living with palliative care needs arising from COPD. The absence of life meaning has the most significant impact, requiring further exploration of both its physical and psychological impact. Rediscovery of life meaning diminishes feelings of worthlessness and hopelessness in daily life and facilitates feelings of inner peace. For those with COPD living with such a relentless symptom burden, a positive existential situation is desirable.

Keywords: palliative care, COPD, existential suffering, end of life care

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1483 Occurrence and Geological Setting of the Black Shales Outcrops in Malaysia

Authors: Hassan M. Baioumy, Yuniarti Ulfa

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Paleozoic, Mesozoic and Cenozoic black shales that can be a potential source of energy and precious metals are widely distributed in Malaysia Peninsula, Sarawak and Sabah. Two Paleozoic black shales outcrops were reported in the Langkawi Island belonging to the Cambrian fluvial Machinchang Formation and the Silurian glaciomarine Singa Formation. More the seventeen occurrences of Paleozoic black shales outcrops have been found in the Peninsular Malaysia that range in age from Devonian, Carboniferous, and Permian in the Terengganu, Perlis, Pahang, and Perak States. Mesozoic black shales outcrops occur in several places in both the Peninsular Malaysia and Sarawak. In the Peninsular Malaysia, Triassic black shales occur in the Nami area, Northern Kedah and in the Pahang area. In Sarawak, Triassic black shales have been reported in the Bau area. Cenozoic black shales outcrops were reported in both Sarawak at Miri area and Sabah at the Ranau and Tenom areas. Preliminary mineralogical and geochemical investigations on some of these black shales outcrops showed distinct compositional variations among these black shales outcrops probably due to variations in their source area composition and/or depositional and diagenetic settings of these shales. Some of these shalese also subjected to post-depositional hydrothermal mineralization that enriched these shales with Au-bearing minerals such as pyrite, calchopyrite, and arsenopyrite. Many of the studied black shales outcrops look rich in organic matter, which increase the possibility of using these black shales as an unconventional energy resource.

Keywords: black shales, energy, mineralization, Malaysia

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1482 Depositional Environment of the Babouchite Rocks of Numidian Formation, Northwestern Tunisia: Mineralogical Study and Geochemical Properties

Authors: Ben Yahia Nouha, Harris Chris, Boussen Slim, Chaabani Fredj

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The present work has set itself the objective of studying non-detritic siliceous rocks in the extreme northwestern of Tunisia. It aims to discuss the origin and depositional environment of siliceous rocks based on petrographic, mineralogical, and geochemical results. The different sections were made in the area of Babouch and the area of Cap-Serrat. The collected samples were subjected to petrographic, mineralogical, and geochemical characterization using different analytical methods: scanning electron microscopy (SEM), X-ray diffraction (XRD), geochemical analysis (ICP- AES), isotopic geochemistry (δ¹⁸O) to assess their suitability for industrial use. These babouchite shows that the mineralogy consists of quartz as the dominant mineral with the total lack of amorphous silica, while clay represents the minor phase. The petrographic examination revealed allowed to deduce that it is a rock of chemical origin deriving from tests of siliceous organisms (the radiolarians). Chemical analyzes show that SiO₂, Al₂O₃, and Fe₂O₃ represent the most abundant oxides. The other oxides are present in negligible quantity. Geochemical data support a biogenic and non-hydrothermal origin of babouchite silica. Oxygen isotopic has shown that babouchites are formed in an environment with a high temperature, ranging from 56°C to 73°C.

Keywords: siliceous rocks, babouchite formation, XRD, chemical analysis, isotopic geochemistry, Northwestern of Tunisia

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1481 Synthesis of Double Dye-Doped Silica Nanoparticles and Its Application in Paper-Based Chromatography

Authors: Ka Ho Yau, Jan Frederick Engels, Kwok Kei Lai, Reinhard Renneberg

Abstract:

Lateral flow test is a prevalent technology in various sectors such as food, pharmacology and biomedical sciences. Colloidal gold (CG) is widely used as the signalling molecule because of the ease of synthesis, bimolecular conjugation and its red colour due to intrinsic SPRE. However, the production of colloidal gold is costly and requires vigorous conditions. The stability of colloidal gold are easily affected by environmental factors such as pH, high salt content etc. Silica nanoparticles are well known for its ease of production and stability over a wide range of solvents. Using reverse micro-emulsion (w/o), silica nanoparticles with different sizes can be produced precisely by controlling the amount of water. By incorporating different water-soluble dyes, a rainbow colour of the silica nanoparticles could be produced. Conjugation with biomolecules such as antibodies can be achieved after surface modification of the silica nanoparticles with organosilane. The optimum amount of the antibodies to be labelled was determined by Bradford Assay. In this work, we have demonstrated the ability of the dye-doped silica nanoparticles as a signalling molecule in lateral flow test, which showed a semi-quantitative measurement of the analyte. The image was further analysed for the LOD=10 ng of the analyte. The working range and the linear range of the test were from 0 to 2.15μg/mL and from 0 to 1.07 μg/mL (R2=0.988) respectively. The performance of the tests was comparable to those using colloidal gold with the advantages of lower cost, enhanced stability and having a wide spectrum of colours. The positives lines can be imaged by naked eye or by using a mobile phone camera for a better quantification. Further research has been carried out in multicolour detection of different biomarkers simultaneously. The preliminary results were promising as there was little cross-reactivity being observed for an optimized system. This approach provides a platform for multicolour detection for a set of biomarkers that enhances the accuracy of diseases diagnostics.

Keywords: colorimetric detection, immunosensor, paper-based biosensor, silica

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1480 Synthesis of Carbon Nanotubes from Coconut Oil and Fabrication of a Non Enzymatic Cholesterol Biosensor

Authors: Mitali Saha, Soma Das

Abstract:

The fabrication of nanoscale materials for use in chemical sensing, biosensing and biological analyses has proven a promising avenue in the last few years. Cholesterol has aroused considerable interest in recent years on account of its being an important parameter in clinical diagnosis. There is a strong positive correlation between high serum cholesterol level and arteriosclerosis, hypertension, and myocardial infarction. Enzyme-based electrochemical biosensors have shown high selectivity and excellent sensitivity, but the enzyme is easily denatured during its immobilization procedure and its activity is also affected by temperature, pH, and toxic chemicals. Besides, the reproducibility of enzyme-based sensors is not very good which further restrict the application of cholesterol biosensor. It has been demonstrated that carbon nanotubes could promote electron transfer with various redox active proteins, ranging from cytochrome c to glucose oxidase with a deeply embedded redox center. In continuation of our earlier work on the synthesis and applications of carbon and metal based nanoparticles, we have reported here the synthesis of carbon nanotubes (CCNT) by burning coconut oil under insufficient flow of air using an oil lamp. The soot was collected from the top portion of the flame, where the temperature was around 6500C which was purified, functionalized and then characterized by SEM, p-XRD and Raman spectroscopy. The SEM micrographs showed the formation of tubular structure of CCNT having diameter below 100 nm. The XRD pattern indicated the presence of two predominant peaks at 25.20 and 43.80, which corresponded to (002) and (100) planes of CCNT respectively. The Raman spectrum (514 nm excitation) showed the presence of 1600 cm-1 (G-band) related to the vibration of sp2-bonded carbon and at 1350 cm-1 (D-band) responsible for the vibrations of sp3-bonded carbon. A nonenzymatic cholesterol biosensor was then fabricated on an insulating Teflon material containing three silver wires at the surface, covered by CCNT, obtained from coconut oil. Here, CCNTs worked as working as well as counter electrodes whereas reference electrode and electric contacts were made of silver. The dimensions of the electrode was 3.5 cm×1.0 cm×0.5 cm (length× width × height) and it is ideal for working with 50 µL volume like the standard screen printed electrodes. The voltammetric behavior of cholesterol at CCNT electrode was investigated by cyclic voltammeter and differential pulse voltammeter using 0.001 M H2SO4 as electrolyte. The influence of the experimental parameters on the peak currents of cholesterol like pH, accumulation time, and scan rates were optimized. Under optimum conditions, the peak current was found to be linear in the cholesterol concentration range from 1 µM to 50 µM with a sensitivity of ~15.31 μAμM−1cm−2 with lower detection limit of 0.017 µM and response time of about 6s. The long-term storage stability of the sensor was tested for 30 days and the current response was found to be ~85% of its initial response after 30 days.

Keywords: coconut oil, CCNT, cholesterol, biosensor

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1479 A Systems Approach to Targeting Cyclooxygenase: Genomics, Bioinformatics and Metabolomics Analysis of COX-1 -/- and COX-2-/- Lung Fibroblasts Providing Indication of Sterile Inflammation

Authors: Abul B. M. M. K. Islam, Mandar Dave, Roderick V. Jensen, Ashok R. Amin

Abstract:

A systems approach was applied to characterize differentially expressed transcripts, bioinformatics pathways, and proteins and prostaglandins (PGs) from lung fibroblasts procured from wild-type (WT), COX-1-/- and COX-2-/- mice to understand system level control mechanism. Bioinformatics analysis of COX-2 and COX-1 ablated cells induced COX-1 and COX-2 specific signature respectively, which significantly overlapped with an 'IL-1β induced inflammatory signature'. This defined novel cross-talk signals that orchestrated coordinated activation of pathways of sterile inflammation sensed by cellular stress. The overlapping signals showed significant over-representation of shared pathways for interferon y and immune responses, T cell functions, NOD, and toll-like receptor signaling. Gene Ontology Biological Process (GOBP) and pathway enrichment analysis specifically showed an increase in mRNA expression associated with: (a) organ development and homeostasis in COX-1-/- cells and (b) oxidative stress and response, spliceosomes and proteasomes activity, mTOR and p53 signaling in COX-2-/- cells. COX-1 and COX-2 showed signs of functional pathways committed to cell cycle and DNA replication at the genomics level. As compared to WT, metabolomics analysis revealed a significant increase in COX-1 mRNA and synthesis of basal levels of eicosanoids (PGE2, PGD2, TXB2, LTB4, PGF1α, and PGF2α) in COX-2 ablated cells and increase in synthesis of PGE2, and PGF1α in COX-1 null cells. There was a compensation of PGE2 and PGF1α in COX-1-/- and COX-2-/- cells. Collectively, these results support a broader, differential and collaborative regulation of both COX-1 and COX-2 pathways at the metabolic, signaling, and genomics levels in cellular homeostasis and sterile inflammation induced by cellular stress.

Keywords: cyclooxygenases, inflammation, lung fibroblasts, systemic

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1478 Preparation and Characterization of Nickel-Tungsten Nanoparticles Using Microemulsion Mediated Synthesis

Authors: S. Pal, R. Singh, S. Sivakumar, D. Kunzru

Abstract:

AOT stabilized reverse micelles of deionized water, dispersed in isooctane have been used to synthesize bimetallic nickel tungsten nanoparticles. Prepared nanoparticles were supported on γ-Al2O3 followed by calcination at 500oC. Characterizations of the nanoparticles were done by TEM, XRD, FTIR, XRF, TGA and BET. XRF results showed that this method gave good composition control with W/Ni weight ratio equal to 3.2. TEM images showed particle size of 5-10 nm. Removal of surfactant after calcination was confirmed by TGA and FTIR.

Keywords: nanoparticles, reverse micelles, nickel, tungsten

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1477 Polymer Impregnated Sulfonated Carbon Composite as a Solid Acid Catalyst for the Dehydration of Xylose to Furfural

Authors: Praveen K. Khatri, Neha Karanwal, Savita Kaul, Suman L. Jain

Abstract:

Conversion of biomass through green chemical routes is of great industrial importance as biomass is considered to be most widely available inexpensive renewable resource that can be used as a raw material for the production of bio fuel and value-added organic products. In this regard, acid catalyzed dehydration of biomass derived pentose sugar (mainly D-xylose) to furfural is a process of tremendous research interest in current scenario due to the wider industrial applications of furfural. Furfural is an excellent organic solvent for refinement of lubricants and separation of butadiene from butene mixture in synthetic rubber fabrication. In addition it also serve as a promising solvent for many organic materials, such as resins, polymers and also used as a building block for synthesis of various valuable chemicals such as furfuryl alcohol, furan, pharmaceutical, agrochemicals and THF. Here in a sulfonated polymer impregnated carbon composite solid acid catalyst (P-C-SO3H) was prepared by the pyrolysis of a polymer matrix impregnated with glucose followed by its sulfonation and used for the dehydration of xylose to furfural. The developed catalyst exhibited excellent activity and provided almost quantitative conversion of xylose with the selective synthesis of furfural. The higher catalytic activity of P-C-SO3H may be due to the more even distribution of polycyclic aromatic hydrocarbons generated from incomplete carbonization of glucose along the polymer matrix network, leading to more available sites for sulfonation which resulted in greater sulfonic acid density in P-C-SO3H as compared to sulfonated carbon catalyst (C-SO3H). In conclusion, we have demonstrated sulfonated polymer impregnated carbon composite (P-C-SO3H) as an efficient and selective solid acid catalyst for the dehydration of xylose to furfural. After completion of the reaction, the catalyst was easily recovered and reused for several runs without noticeable loss in its activity and selectivity.

Keywords: Solid acid , Biomass conversion, Xylose Dehydration, Heterogeneous catalyst

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1476 Harnessing Sunlight for Clean Water: Scalable Approach for Silver-Loaded Titanium Dioxide Nanoparticles

Authors: Satam Alotibi, Muhammad J. Al-Zahrani, Fahd K. Al-Naqidan, Turki S. Hussein, Moteb Alotaibi, Mohammed Alyami, Mahdy M. Elmahdy, Abdellah Kaiba, Fatehia S. Alhakami, Talal F. Qahtan

Abstract:

Water pollution is a critical global challenge that demands scalable and effective solutions for water decontamination. In this captivating research, we unveil a groundbreaking strategy for harnessing solar energy to synthesize silver (Ag) clusters on stable titanium dioxide (TiO₂) nanoparticles dispersed in water, without the need for traditional stabilization agents. These Ag-loaded TiO₂ nanoparticles exhibit exceptional photocatalytic activity, surpassing that of pristine TiO₂ nanoparticles, offering a promising solution for highly efficient water decontamination under sunlight irradiation. To the best knowledge, we have developed a unique method to stabilize TiO₂ P25 nanoparticles in water without the use of stabilization agents. This breakthrough allows us to create an ideal platform for the solar-driven synthesis of Ag clusters. Under sunlight irradiation, the stable dispersion of TiO₂ P25 nanoparticles acts as a highly efficient photocatalyst, generating electron-hole pairs. The photogenerated electrons effectively reduce silver ions derived from a silver precursor, resulting in the formation of Ag clusters. The Ag clusters loaded on TiO₂ P25 nanoparticles exhibit remarkable photocatalytic activity for water decontamination under sunlight irradiation. Acting as active sites, these Ag clusters facilitate the generation of reactive oxygen species (ROS) upon exposure to sunlight. These ROS play a pivotal role in rapidly degrading organic pollutants, enabling efficient water decontamination. To confirm the success of our approach, we characterized the synthesized Ag-loaded TiO₂ P25 nanoparticles using cutting-edge analytical techniques, such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and spectroscopic methods. These characterizations unequivocally confirm the successful synthesis of Ag clusters on stable TiO₂ P25 nanoparticles without traditional stabilization agents. Comparative studies were conducted to evaluate the superior photocatalytic performance of Ag-loaded TiO₂ P25 nanoparticles compared to pristine TiO₂ P25 nanoparticles. The Ag clusters loaded on TiO₂ P25 nanoparticles exhibit significantly enhanced photocatalytic activity, benefiting from the synergistic effect between the Ag clusters and TiO₂ nanoparticles, which promotes ROS generation for efficient water decontamination. Our scalable strategy for synthesizing Ag clusters on stable TiO₂ P25 nanoparticles without stabilization agents presents a game-changing solution for highly efficient water decontamination under sunlight irradiation. The use of commercially available TiO₂ P25 nanoparticles streamlines the synthesis process and enables practical scalability. The outstanding photocatalytic performance of Ag-loaded TiO₂ P25 nanoparticles opens up new avenues for their application in large-scale water treatment and remediation processes, addressing the urgent need for sustainable water decontamination solutions.

Keywords: water pollution, solar energy, silver clusters, TiO₂ nanoparticles, photocatalytic activity

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1475 Guidelines to Designing Generic Protocol for Responding to Chemical, Biological, Radiological and Nuclear Incidents

Authors: Mohammad H. Yarmohammadian, Mehdi Nasr Isfahani, Elham Anbari

Abstract:

Introduction: The awareness of using chemical, biological, and nuclear agents in everyday industrial and non-industrial incidents has increased recently; release of these materials can be accidental or intentional. Since hospitals are the forefronts of confronting Chemical, Biological, Radiological and Nuclear( CBRN) incidents, the goal of the present research was to provide a generic protocol for CBRN incidents through a comparative review of CBRN protocols and guidelines of different countries and reviewing various books, handbooks and papers. Method: The integrative approach or research synthesis was adopted in this study. First a simple narrative review of programs, books, handbooks, and papers about response to CBRN incidents in different countries was carried out. Then the most important and functional information was discussed in the form of a generic protocol in focus group sessions and subsequently confirmed. Results: Findings indicated that most of the countries had various protocols, guidelines, and handbooks for hazardous materials or CBRN incidents. The final outcome of the research synthesis was a 50 page generic protocol whose main topics included introduction, definition and classification of CBRN agents, four major phases of incident and disaster management cycle, hospital response management plan, equipment, and recommended supplies and antidotes for decontamination (radiological/nuclear, chemical, biological); each of these also had subtopics. Conclusion: In the majority of international protocols, guidelines, handbooks and also international and Iranian books and papers, there is an emphasis on the importance of incident command system, determining the safety degree of decontamination zones, maps of decontamination zones, decontamination process, triage classifications, personal protective equipment, and supplies and antidotes for decontamination; these are the least requirements for such incidents and also consistent with the provided generic protocol.

Keywords: hospital, CBRN, decontamination, generic protocol, CBRN Incidents

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1474 Enhanced Ripening Behaviour of Manganese Doped Cadmium Selenide Quantum Dots (Mn-doped CdSe QDs)

Authors: N. A. Hamizi, M. R. Johan, Y. H. Hor, A. N. Sabri, Y. Y. A. Yong

Abstract:

In this research, Mn-doped CdSe QDs is synthesized by using paraffin liquid as the reacting solvent and oleic acid as the ligands for Cd in order to produce Mn-doped CdSe QDs in zinc-blende crystal structure. Characterization studies for synthesized Mn-doped CdSe QDs are carried out using UV-visible and photoluminescence spectroscopy. The absorption wavelengths in UV-vis test and emission wavelengths in PL test were increase with the increases in the ripening temperature and time respectively.

Keywords: semiconductor, chemical synthesis, optical properties, ripening

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1473 Polymer Matrices Based on Natural Compounds: Synthesis and Characterization

Authors: Sonia Kudlacik-Kramarczyk, Anna Drabczyk, Dagmara Malina, Bozena Tyliszczak, Agnieszka Sobczak-Kupiec

Abstract:

Introduction: In the preparation of polymer materials, compounds of natural origin are currently gaining more and more interest. This is particularly noticeable in the case of synthesis of materials considered for biomedical use. Then, selected material has to meet many requirements. It should be characterized by non-toxicity, biodegradability and biocompatibility. Therefore special attention is directed to substances such as polysaccharides, proteins or substances that are the basic building components of proteins, i.e. amino acids. These compounds may be crosslinked with other reagents that leads to the preparation of polymer matrices. Such amino acids as e.g. cysteine or histidine. On the other hand, previously mentioned requirements may be met by polymers obtained as a result of biosynthesis, e.g. polyhydroxybutyrate. This polymer belongs to the group of aliphatic polyesters that is synthesized by microorganisms (selected strain of bacteria) under specific conditions. It is possible to modify matrices based on given polymer with substances of various origin. Such a modification may result in the change of their properties or/and in providing the material with new features desirable in viewpoint of specific application. Described materials are synthesized using UV radiation. Process of photopolymerization is fast, waste-free and enables to obtain final products with favorable properties. Methodology: Polymer matrices have been prepared by means of photopolymerization. First step involved the preparation of solutions of particular reagents and mixing them in the appropriate ratio. Next, crosslinking agent and photoinitiator have been added to the reaction mixture and the whole was poured into the Petri dish and treated with UV radiation. After the synthesis, polymer samples were dried at room temperature and subjected to the numerous analyses aimed at the determining their physicochemical properties. Firstly, sorption properties of obtained polymer matrices have been determined. Next, mechanical properties have been characterized, i.e. tensile strength. The ability to deformation under applied stress of all prepared polymer matrices has been checked. Such a property is important in viewpoint of the application of analyzed materials e.g. as wound dressings. Wound dressings have to be elastic because depending on the location of the wound and its mobility, such a dressing has to adhere properly to the wound. Furthermore, considering the use of the materials for biomedical purposes it is essential to determine its behavior in environments simulating these ones occurring in human body. Therefore incubation studies using selected liquids have also been conducted. Conclusions: As a result of photopolymerization process, polymer matrices based on natural compounds have been prepared. These exhibited favorable mechanical properties and swelling ability. Moreover, biocompatibility in relation to simulated body fluids has been stated. Therefore it can be concluded that analyzed polymer matrices constitute an interesting materials that may be considered for biomedical use and may be subjected to the further more advanced analyses using specific cell lines.

Keywords: photopolymerization, polymer matrices, simulated body fluids, swelling properties

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1472 Mineralogical and Geochemical Constraints on the Origin and Environment of Numidian Siliceous Sedimentary Rocks of the Extreme Northwest Tunisia

Authors: Ben Yahia Nouha, Harris Chris, Sebei Abdelaziz, Boussen Slim, Chaabani Fredj

Abstract:

The present work has set itself the objective of studying non-detritic siliceous rocks of the extreme northwest Tunisia. It aims to examine the origin and their sedimentary depositional environment based on mineralogical and geochemical characteristics. The different sections were located in the area of Babouch and the area of Tabarka. The collected samples were subjected to mineralogical and geochemical characterization using different analytical methods: X-ray diffraction (XRD), geochemical analysis (ICP- AES), isotopic geochemistry (δ18O), to assess their suitability for industrial use. X-ray powder diffraction of the pure siliceous rock indicates quartz as the major mineral, with the total lack of amorphous silica. Trace impurities, such as carbonate and clay minerals, are concealed in the analytical results. The petrographic examination revealed allowed us to deduce that this rock was deriving from tests of siliceous organisms (the radiolarians). The chemical composition shows that SiO2, Al2O3, and Fe2O3 represent the most abundant oxides. The other oxides are present in negligible quantities. Geochemical data support a biogenic and non-hydrothermal origin of babouchite silica. Oxygen isotopic has shown that babouchites were formed in an environment with a high temperature ranging from 56 °C to 73 °C.

Keywords: biogenic silica, babouchite formation, XRD, chemical analysis, oxygen isotopic, northwest tunisia

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1471 Synthesis of 4', 6'-Bis-(2, 4-Dinitro-Aniline)-(2'-Aryl-Amine)-S-Triazine and Biological Activity Studies

Authors: Dilesh Indorkar

Abstract:

The aromatic, six membered ring containing three nitrogen atoms are known as triazines. Three triazines are theoretically possible, 1,3,5-triazine, 1,2,4-triazine and 1,2,3-triazine[1]. The 1,3,5-triazines are amongst the oldest known organic compounds. Originally they were called the symmetric triazines. Usuelly abbreviated to s- or sys triazines. The numbering follows the usual convention of beginning at the hetero atom as shown for the parent compound 1,3,5-triazine (I). The triazine rings, each contain 6 pi electrons which fill three bonding molecular orbital there are also three pairs of non bonding electrons in each molecule which are responsible for basic properties of the compounds.

Keywords: s-triazine, thiazoline, isoxazoline, benzoxazine heterocyclic

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1470 Improving Binding Selectivity in Molecularly Imprinted Polymers from Templates of Higher Biomolecular Weight: An Application in Cancer Targeting and Drug Delivery

Authors: Ben Otange, Wolfgang Parak, Florian Schulz, Michael Alexander Rubhausen

Abstract:

The feasibility of extending the usage of molecular imprinting technique in complex biomolecules is demonstrated in this research. This technique is promising in diverse applications in areas such as drug delivery, diagnosis of diseases, catalysts, and impurities detection as well as treatment of various complications. While molecularly imprinted polymers MIP remain robust in the synthesis of molecules with remarkable binding sites that have high affinities to specific molecules of interest, extending the usage to complex biomolecules remains futile. This work reports on the successful synthesis of MIP from complex proteins: BSA, Transferrin, and MUC1. We show in this research that despite the heterogeneous binding sites and higher conformational flexibility of the chosen proteins, relying on their respective epitopes and motifs rather than the whole template produces highly sensitive and selective MIPs for specific molecular binding. Introduction: Proteins are vital in most biological processes, ranging from cell structure and structural integrity to complex functions such as transport and immunity in biological systems. Unlike other imprinting templates, proteins have heterogeneous binding sites in their complex long-chain structure, which makes their imprinting to be marred by challenges. In addressing this challenge, our attention is inclined toward the targeted delivery, which will use molecular imprinting on the particle surface so that these particles may recognize overexpressed proteins on the target cells. Our goal is thus to make surfaces of nanoparticles that specifically bind to the target cells. Results and Discussions: Using epitopes of BSA and MUC1 proteins and motifs with conserved receptors of transferrin as the respective templates for MIPs, significant improvement in the MIP sensitivity to the binding of complex protein templates was noted. Through the Fluorescence Correlation Spectroscopy FCS measurements on the size of protein corona after incubation of the synthesized nanoparticles with proteins, we noted a high affinity of MIPs to the binding of their respective complex proteins. In addition, quantitative analysis of hard corona using SDS-PAGE showed that only a specific protein was strongly bound on the respective MIPs when incubated with similar concentrations of the protein mixture. Conclusion: Our findings have shown that the merits of MIPs can be extended to complex molecules of higher biomolecular mass. As such, the unique merits of the technique, including high sensitivity and selectivity, relative ease of synthesis, production of materials with higher physical robustness, and higher stability, can be extended to more templates that were previously not suitable candidates despite their abundance and usage within the body.

Keywords: molecularly imprinted polymers, specific binding, drug delivery, high biomolecular mass-templates

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