Search results for: hybridization chain reaction

Authors: Matthew F. Gibson, Narasimha D. Rao, Raphael B. Slade, Joana Portugal Pereira, Joeri Rogelj

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Globally, India’s population is among the most severely impacted by nutrient deficiency, yet millions of tonnes of food are lost before reaching consumers. Across food groups, grains represent the largest share of daily calories and overall losses by mass in India. If current losses remain unresolved and follow projected population rates, we estimate, by 2030, losses from grains for human consumption could increase by 1.3-1.8 million tonnes (Mt) per year against current levels of ~10 Mt per year. This study quantifies energy input to minimise storage losses across India, responsible for a quarter of grain supply chain losses. In doing so, we identify and explore a Sustainable Development Goal (SDG) triplet between SDG₂, SDG₇, and SDG₁₂ and provide insight for development of joined up agriculture and health policy in the country. Analyzing rice, wheat, maize, bajra, and sorghum, we quantify one route to reduce losses in supply chains, by modelling the energy input to maintain favorable climatic conditions in modern silo storage. We quantify key nutrients (calories, protein, zinc, iron, vitamin A) contained within these losses and calculate roughly how much deficiency in these dietary components could be reduced if grain losses were eliminated. Our modelling indicates, with appropriate uncertainty, maize has the highest energy input intensity for storage, at 110 kWh per tonne of grain (kWh/t), and wheat the lowest (72 kWh/t). This energy trade-off represents 8%-16% of the energy input required in grain production. We estimate if grain losses across the supply chain were saved and targeted to India’s nutritionally deficient population, average protein deficiency could reduce by 46%, calorie by 27%, zinc by 26%, and iron by 11%. This study offers insight for development of Indian agriculture, food, and health policy by first quantifying and then presenting benefits and trade-offs of tackling food grain losses.

Keywords: energy, food loss, grain storage, hunger, India, sustainable development goal, SDG

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Authors: Laura O’Halloran, Zhipeng Cao, Clare M. Kelly, Hugh Garavan, Robert Whelan

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Reaction time (RT) variability on cognitive tasks provides the index of the efficiency of executive control processes (e.g. attention and inhibitory control) and is considered to be a hallmark of clinical disorders, such as attention-deficit disorder (ADHD). Increased RT variability is associated with structural and functional brain differences in children and adults with various clinical disorders, as well as poorer task performance accuracy. Furthermore, the strength of functional connectivity across various brain networks, such as the negative relationship between the task-negative default mode network and task-positive attentional networks, has been found to reflect differences in RT variability. Although RT variability may provide an index of attentional efficiency, as well as being a useful indicator of neurological impairment, the brain substrates associated with RT variability remain relatively poorly defined, particularly in a healthy sample. Method: Firstly, we used the intra-individual coefficient of variation (ICV) as an index of RT variability from “Go” responses on the Stop Signal Task. We then examined the functional and structural neural correlates of ICV in a large sample of 14-year old healthy adolescents (n=1719). Of these, a subset had elevated symptoms of ADHD (n=80) and was compared to a matched non-symptomatic control group (n=80). The relationship between brain activity during successful and unsuccessful inhibitions and gray matter volume were compared with the ICV. A mediation analysis was conducted to examine if specific brain regions mediated the relationship between ADHD symptoms and ICV. Lastly, we looked at functional connectivity across various brain networks and quantified both positive and negative correlations during “Go” responses on the Stop Signal Task. Results: The brain data revealed that higher ICV was associated with increased structural and functional brain activation in the precentral gyrus in the whole sample and in adolescents with ADHD symptoms. Lower ICV was associated with lower activation in the anterior cingulate cortex (ACC) and medial frontal gyrus in the whole sample and in the control group. Furthermore, our results indicated that activation in the precentral gyrus (Broadman Area 4) mediated the relationship between ADHD symptoms and behavioural ICV. Conclusion: This is the first study first to investigate the functional and structural correlates of ICV collectively in a large adolescent sample. Our findings demonstrate a concurrent increase in brain structure and function within task-active prefrontal networks as a function of increased RT variability. Furthermore, structural and functional brain activation patterns in the ACC, and medial frontal gyrus plays a role-optimizing top-down control in order to maintain task performance. Our results also evidenced clear differences in brain morphometry between adolescents with symptoms of ADHD but without clinical diagnosis and typically developing controls. Our findings shed light on specific functional and structural brain regions that are implicated in ICV and yield insights into effective cognitive control in healthy individuals and in clinical groups.

Keywords: ADHD, fMRI, reaction-time variability, default mode, functional connectivity

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Authors: Hamid Reza Mahdipoor, Mehdi Bahrami, Mohammad Bodaghi, Seyed Ali Akbar Mansoori

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Nowadays, with stricter limitations to reduce emissions, considerable penalties are imposed if pollution limits are exceeded. Therefore, refineries, along with focusing on improving the quality of their products, are also focused on producing products with the least environmental impact. The duty of the sulfur recovery unit (SRU) is to convert H₂S gas coming from the upstream units to elemental sulfur and minimize the burning of sulfur compounds to SO₂. The Claus process is a common process for converting H₂S to sulfur, including a reaction furnace followed by catalytic reactors and sulfur condensers. In addition to a Claus section, SRUs usually consist of a tail gas treatment (TGT) section to decrease the concentration of SO₂ in the flue gas below the emission limits. To operate an SRU properly, the flow rate of combustion air to the reaction furnace must be adjusted so that the Claus reaction is performed according to stoichiometry. Accurate control of the air demand leads to an optimum recovery of sulfur during the flow and composition fluctuations in the acid gas feed. Therefore, the major control system in the SRU is the air demand control loop, which includes a feed-forward control system based on predetermined feed flow rates and a feed-back control system based on the signal from the tail gas online analyzer. The use of online analyzers requires compliance with the installation and operation instructions. Unfortunately, most of these analyzers in Iran are out of service for different reasons, like the low importance of environmental issues and a lack of access to after-sales services due to sanctions. In this paper, an SRU in Iran was simulated and calibrated using industrial experimental data. Afterward, the effect of the malfunction of the online analyzer on the performance of SRU was investigated using the calibrated simulation. The results showed that an increase in the SO₂ concentration in the tail gas led to an increase in the temperature of the reduction reactor in the TGT section. This increase in temperature caused the failure of TGT and increased the concentration of SO₂ from 750 ppm to 35,000 ppm. In addition, the lack of a control system for the adjustment of the combustion air caused further increases in SO₂ emissions. In some processes, the major variable cannot be controlled directly due to difficulty in measurement or a long delay in the sampling system. In these cases, a secondary variable, which can be measured more easily, is considered to be controlled. With the correct selection of this variable, the main variable is also controlled along with the secondary variable. This strategy for controlling a process system is referred to as inferential control" and is considered in this paper. Therefore, a sensitivity analysis was performed to investigate the sensitivity of other measurable parameters to input disturbances. The results revealed that the output temperature of the first Claus reactor could be used for inferential control of the combustion air. Applying this method to the operation led to maximizing the sulfur recovery in the Claus section.

Keywords: sulfur recovery, online analyzer, inferential control, SO₂ emission

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Authors: Kishor Kumar Sadasivuni, Mizaj Shabil Sha, Assim Alajali, Godlaveeti Sreenivasa Kumar, Aboubakr M. Abdullah, Bijandra Kumar, Mithra Geetha

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A potential pathway for efficient hydrogen production from water splitting electrolysis involves catalysis or electrocatalysis, which plays a crucial role in energy conversion and storage. Hydrogen generated by electrocatalytic water splitting requires active, stable, and low-cost catalysts or electrocatalysts to be developed for practical applications. In this study, we evaluated combination of 2D materials of NiS nanoparticle catalysts for hydrogen evolution reactions. The photocatalytic H₂ production rate of this nanoparticle is high and exceeds that obtained on components alone. Nanoparticles serve as electron collectors and transporters, which explains this improvement. Moreover, a current density was recorded at reduced working potential by 0.393 mA. Calculations based on density functional theory indicate that the nanoparticle's hydrogen evolution reaction catalytic activity is caused by strong interaction between its components at the interface. The samples were analyzed by XPS and morphologically by FESEM for the best outcome, depending on their structural shapes. Use XPS and morphologically by FESEM for the best results. This nanocomposite demonstrated higher electro-catalytic activity, and a low tafel slope of 60 mV/dec. Additionally, despite 1000 cycles into a durability test, the electrocatalyst still displays excellent stability with minimal current loss. The produced catalyst has shown considerable potential for use in the evolution of hydrogen due to its robust synthesis. According to these findings, the combination of 2D materials of nickel sulfide sample functions as good electocatalyst for H₂ evolution. Additionally, the research being done in this fascinating field will surely push nickel sulfide-based technology closer to becoming an industrial reality and revolutionize existing energy issues in a sustainable and clean manner.

Keywords: electrochemical hydrogenation, nickel sulfide, electrocatalysts, energy conversion, catalyst

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Authors: Maria Miranda-Medina, Sara Salopek, Andras Vernes, Martin Jech

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Sliding lubricated surfaces induce the formation of tribofilms that reduce friction, wear and prevent large-scale damage of contact parts. Engine oils and lubricants use antiwear and antioxidant additives such as zinc dialkyldithiophosphate (ZDDP) from where protective tribofilms are formed by degradation. The ZDDP tribofilms are described as a two-layer structure composed of inorganic polymer material. On the top surface, the long chain polyphosphate is a zinc phosphate and in the bulk, the short chain polyphosphate is a mixed Fe/Zn phosphate with a gradient concentration. The polyphosphate chains are partially adherent to steel surface through a sulfide and work as anti-wear pads. In this contribution, ZDDP tribofilms formed on gray cast iron surfaces are studied. The tribofilms were generated in a reciprocating sliding tribometer with a piston ring-cylinder liner configuration. Fully formulated oil of SAE grade 5W-30 was used as lubricant during two tests at 40Hz and 50Hz. For the estimation of the tribofilm thicknesses, spectroscopic ellipsometry was used due to its high accuracy and non-destructive nature. Ellipsometry works under an optical principle where the change in polarisation of light reflected by the surface, is associated with the refractive index of the surface material or to the thickness of the layer deposited on top. Ellipsometrical responses derived from tribofilms are modelled by effective medium approximation (EMA), which includes the refractive index of involved materials, homogeneity of the film and thickness. The materials composition was obtained from x-ray photoelectron spectroscopic studies, where the presence of ZDDP, O and C was confirmed. From EMA models it was concluded that tribofilms formed at 40 Hz are thicker and more homogeneous than the ones formed at 50 Hz. In addition, the refractive index of each material is mixed to derive an effective refractive index that describes the optical composition of the tribofilm and exhibits a maximum response in the UV range, being a characteristic of glassy semitransparent films.

Keywords: effective medium approximation, reciprocating sliding tribometer, spectroscopic ellipsometry, zinc dialkyldithiophosphate

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Authors: Dianelys Vega, Carlos Magluta, Ney Roitman

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The simulation of loads induced by walking people in civil engineering structures is still challenging It has been the focus of considerable research worldwide in the recent decades due to increasing number of reported vibration problems in pedestrian structures. One of the most important key in the designing of slender structures is the Human-Structure Interaction (HSI). How moving people interact with structures and the effect it has on their dynamic responses is still not well understood. To rely on calibrated pedestrian models that accurately estimate the structural response becomes extremely important. However, because of the complexity of the pedestrian mechanisms, there are still some gaps in knowledge and more reliable models need to be investigated. On this topic several authors have proposed biodynamic models to represent the pedestrian, whether these models provide a consistent approximation to physical reality still needs to be studied. Therefore, this work comes to contribute to a better understanding of this phenomenon bringing an experimental validation of a pedestrian walking model and a Human-Structure Interaction model. In this study, a bi-dimensional bipedal walking model was used to represent the pedestrians along with an interaction model which was applied to a prototype footbridge. Numerical models were implemented in MATLAB. In parallel, experimental tests were conducted in the Structures Laboratory of COPPE (LabEst), at Federal University of Rio de Janeiro. Different test subjects were asked to walk at different walking speeds over instrumented force platforms to measure the walking force and an accelerometer was placed at the waist of each subject to measure the acceleration of the center of mass at the same time. By fitting the step force and the center of mass acceleration through successive numerical simulations, the model parameters are estimated. In addition, experimental data of a walking pedestrian on a flexible structure was used to validate the interaction model presented, through the comparison of the measured and simulated structural response at mid span. It was found that the pedestrian model was able to adequately reproduce the ground reaction force and the center of mass acceleration for normal and slow walking speeds, being less efficient for faster speeds. Numerical simulations showed that biomechanical parameters such as leg stiffness and damping affect the ground reaction force, and the higher the walking speed the greater the leg length of the model. Besides, the interaction model was also capable to estimate with good approximation the structural response, that remained in the same order of magnitude as the measured response. Some differences in frequency spectra were observed, which are presumed to be due to the perfectly periodic loading representation, neglecting intra-subject variabilities. In conclusion, this work showed that the bipedal walking model could be used to represent walking pedestrians since it was efficient to reproduce the center of mass movement and ground reaction forces produced by humans. Furthermore, although more experimental validations are required, the interaction model also seems to be a useful framework to estimate the dynamic response of structures under loads induced by walking pedestrians.

Keywords: biodynamic models, bipedal walking models, human induced loads, human structure interaction

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Authors: Kutangila Malundama Succes, Koita Mahamadou

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In the context of climate change and demographic pressure, groundwater has emerged as an essential and strategic resource whose sustainability relies on good management. The accuracy and relevance of decisions made in managing these resources depend on the availability and quality of scientific information they must rely on. It is, therefore, more urgent to improve the state of knowledge on groundwater to ensure sustainable management. This study is conducted for the particular case of the aquifers of the transboundary sedimentary basin of Taoudéni in its Burkinabe part. Indeed, Burkina Faso (and the Sahel region in general), marked by low rainfall, has experienced episodes of severe drought, which have justified the use of groundwater as the primary source of water supply. This study aims to improve knowledge of the hydrogeology of this area to achieve sustainable management of transboundary groundwater resources. The methodological approach first described lithological units regarding the extension and succession of different layers. Secondly, the hydrodynamic behavior of these units was studied through the analysis of spatio-temporal variations of piezometric. The data consists of 692 static level measurement points and 8 observation wells located in the usual manner in the area and capturing five of the identified geological formations. Monthly piezometric level chronicles are available for each observation and cover the period from 1989 to 2020. The temporal analysis of piezometric, carried out in comparison with rainfall chronicles, revealed a general upward trend in piezometric levels throughout the basin. The reaction of the groundwater generally occurs with a delay of 1 to 2 months relative to the flow of the rainy season. Indeed, the peaks of the piezometric level generally occur between September and October in reaction to the rainfall peaks between July and August. Low groundwater levels are observed between May and July. This relatively slow reaction of the aquifer is observed in all wells. The influence of the geological nature through the structure and hydrodynamic properties of the layers was deduced. The spatial analysis reveals that piezometric contours vary between 166 and 633 m with a trend indicating flow that generally goes from southwest to northeast, with the feeding areas located towards the southwest and northwest. There is a quasi-concordance between the hydrogeological basins and the overlying hydrological basins, as well as a bimodal flow with a component following the topography and another significant component deeper, controlled by the regional gradient SW-NE. This latter component may present flows directed from the high reliefs towards the sources of Nasso. In the source area (Kou basin), the maximum average stock variation, calculated by the Water Table Fluctuation (WTF) method, varies between 35 and 48.70 mm per year for 2012-2014.

Keywords: hydrodynamic behaviour, taoudeni basin, piezometry, water table fluctuation

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Authors: Semire Yekta

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Many online retailers set up manual review teams to overcome the limitations of automated online fraud detection systems. This study critically examines the strategies they adapt in their decision-making process to set apart fraudulent individuals from non-fraudulent online shoppers. The study uses a mix method research approach. 32 in-depth interviews have been conducted alongside with participant observation and auto-ethnography. The study found out that all steps of the decision-making process are significantly affected by a level of subjectivity, personal understandings of online fraud, preferences and judgments and not necessarily by objectively identifiable facts. Rather clearly knowing who the fraudulent individuals are, the team members have to predict whether they think the customer might be a fraudster. Common strategies used are relying on the classification and fraud scorings in the automated fraud detection systems, weighing up arguments for and against the customer and making a decision, using cancellation to test customers’ reaction and making use of personal experiences and “the sixth sense”. The interaction in the team also plays a significant role given that some decisions turn into a group discussion. While customer data represent the basis for the decision-making, fraud management teams frequently make use of Google search and Google Maps to find out additional information about the customer and verify whether the customer is the person they claim to be. While this, on the one hand, raises ethical concerns, on the other hand, Google Street View on the address and area of the customer puts customers living in less privileged housing and areas at a higher risk of being classified as fraudsters. Phone validation is used as a final measurement to make decisions for or against the customer when previous strategies and Google Search do not suffice. However, phone validation is also characterized by individuals’ subjectivity, personal views and judgment on customer’s reaction on the phone that results in a final classification as genuine or fraudulent.

Keywords: online fraud, data mining, manual review, social construction

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Authors: Thauane Silva, Gabrielle do Vale, Andre Ferreira, Marilda Siqueira, Thiago Moreno L. Souza, Milene D. Miranda

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The exposure of A(H1N1)pdm09-infected epithelial cells (HeLa) to HIV-1 viral particles, or its gp120, enhanced interferon-induced transmembrane protein (IFITM3) content, a viral restriction factor (RF), resulting in a decrease in influenza replication. The gp120 binds to CCR5 (R5) or CXCR4 (X4) cell receptors during HIV-1 infection. Then, it is possible that the endogenous ligands of these receptors also modulate the expression of IFITM3 and other cellular factors that restrict influenza virus replication. Thus, the aim of this study is to analyze the role of cellular receptors R5 and X4 in modulating RFs in order to inhibit the replication of the influenza virus. A549 cells were treated with 2x effective dose (ED50) of endogenous R5 or X4 receptor agonists, CCL3 (20 ng/ml), CCL4 (10 ng/ml), CCL5 (10 ng/ml) and CXCL12 (100 ng/mL) or exogenous agonists, gp120 Bal-R5, gp120 IIIB-X4 and its mutants (5 µg/mL). The interferon α (10 ng/mL) and oseltamivir (60 nM) were used as a control. After 24 h post agonists exposure, the cells were infected with virus influenza A(H3N2) at 2 MOI (multiplicity of infection) for 1 h. Then, 24 h post infection, the supernatant was harvested and, the viral titre was evaluated by qRT-PCR. To evaluate IFITM3 and SAM and HD domain containing deoxynucleoside triphosphate triphosphohydrolase 1 (SAMHD1) protein levels, A549 were exposed to agonists for 24 h, and the monolayer was lysed with Laemmli buffer for western blot (WB) assay or fixed for indirect immunofluorescence (IFI) assay. In addition to this, we analyzed other RFs modulation in A549, after 24 h post agonists exposure by customized RT² Profiler Polymerase Chain Reaction Array. We also performed a functional assay in which SAMHD1-knocked-down, by single-stranded RNA (siRNA), A549 cells were infected with A(H3N2). In addition, the cells were treated with guanosine to assess the regulatory role of dNTPs by SAMHD1. We found that R5 and X4 agonists inhibited influenza replication in 54 ± 9%. We observed a four-fold increase in SAMHD1 transcripts by RFs mRNA quantification panel. After 24 h post agonists exposure, we did not observe an increase in IFITM3 protein levels through WB or IFI assays, but we observed an upregulation up to three-fold in the protein content of SAMHD1, in A549 exposed to agonists. Besides this, influenza replication enhanced in 20% in cell cultures that SAMDH1 was knockdown. Guanosine treatment in cells exposed to R5 ligands further inhibited influenza virus replication, suggesting that the inhibitory mechanism may involve the activation of the SAMHD1 deoxynucleotide triphosphohydrolase activity. Thus, our data show for the first time a direct relationship of SAMHD1 and inhibition of influenza replication, and provides perspectives for new studies on the signaling modulation, through cellular receptors, to induce proteins of great importance in the control of relevant infections for public health.

Keywords: chemokine receptors, gp120, influenza, virus restriction factors

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Authors: Malik Sajjad Mehmood, Aisha Ali, Hamna Khan, Tariq Yasin, Masroor Ikram

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Ultra-high molecular weight polyethylene (UHMWPE) is one of the polymers belongs to polyethylene (PE) family having monomer –CH2– and average molecular weight is approximately 3-6 million g/mol. Due its chemical, mechanical, physical and biocompatible properties, it has been extensively used in the field of electrical insulation, medicine, orthopedic, microelectronics, engineering, chemistry and the food industry etc. In order to alter/modify the properties of UHMWPE for particular application of interest, certain various procedures are in practice e.g. treating the material with high energy irradiations like gamma ray, e-beam, and ion bombardment. Radiation treatment of UHMWPE induces free radicals within its matrix, and these free radicals are the precursors of chain scission, chain accumulation, formation of double bonds, molecular emission, crosslinking etc. All the aforementioned physical and chemical processes are mainly responsible for the modification of polymers properties to use them in any particular application of our interest e.g. to fabricate LEDs, optical sensors, antireflective coatings, polymeric optical fibers, and most importantly for radiation dosimetry applications. It is therefore, to check the feasibility of using UHMWPE for radiation dosimetery applications, the compressed sheets of UHMWPE were irradiated at room temperature (~25°C) for total dose values of 30 kGy and 100 kGy, respectively while one were kept un-irradiated as reference. Transmittance data (from 400 nm to 800 nm) of e-beam irradiated UHMWPE and its hybrids were measured by using Muller matrix spectro-polarimeter. As a result significant changes occur in the absorption behavior of irradiated samples. To analyze these (radiation induced) changes in polymer matrix Urbach edge method and modified Tauc’s equation has been used. The results reveal that optical activation energy decreases with irradiation. The values of activation energies are 2.85 meV, 2.48 meV, and 2.40 meV for control, 30 kGy, and 100 kGy samples, respectively. Direct and indirect energy band gaps were also found to decrease with irradiation due to variation of C=C unsaturation in clusters. We believe that the reported results would open new horizons for radiation dosimetery applications.

Keywords: electron beam, radiation dosimetry, Tauc’s equation, UHMWPE, Urbach method

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Authors: Abu Yousuf, Maksudur Rahman Khan, Ahasanul Karim, Amirul Islam, Minhaj Uddin Monir, Sharmin Sultana, Domenico Pirozzi

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Traditional biodiesel feedstock like edible oils or plant oils, animal fats and cooking waste oil have been replaced by microbial oil in recent research of biodiesel synthesis. The well-known community of microbial oil producers includes microalgae, oleaginous yeast and seaweeds. Conventional transesterification of microbial oil to produce biodiesel is lethargic, energy consuming, cost-ineffective and environmentally unhealthy. This process follows several steps such as microbial biomass drying, cell disruption, oil extraction, solvent recovery, oil separation and transesterification. Therefore, direct transesterification of biodiesel synthesis has been studying for last few years. It combines all the steps in a single reactor and it eliminates the steps of biomass drying, oil extraction and separation from solvent. Apparently, it seems to be cost-effective and faster process but number of difficulties need to be solved to make it large scale applicable. The main challenges are microbial cell disruption in bulk volume and make faster the esterification reaction, because water contents of the medium sluggish the reaction rate. Several methods have been proposed but none of them is up to the level to implement in large scale. It is still a great challenge to extract maximum lipid from microbial cells (yeast, fungi, algae) investing minimum energy. Electroporation technique results a significant increase in cell conductivity and permeability caused due to the application of an external electric field. Electroporation is required to alter the size and structure of the cells to increase their porosity as well as to disrupt the microbial cell walls within few seconds to leak out the intracellular lipid to the solution. Therefore, incorporation of electroporation techniques contributed in direct transesterification of microbial lipids by increasing the efficiency of biodiesel production rate.

Keywords: biodiesel, electroporation, microbial lipids, transesterification

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Authors: Lishuang Ma

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Charge transfer (CT) complex, also known as Electron donor-acceptor (EDA) complex, has received attentions increasingly in the field of synthetic chemistry community, due to the CT complex can absorb the visible light through the intermolecular charge transfer excited states, various of catalyst-free photochemical transformations under mild visible-light conditions. However, a number of fundamental questions are still ambiguous, such as the origin of visible light absorption, the photochemical and photophysical properties of the CT complex, as well as the detailed mechanism of the radical coupling pathways mediated by CT complex. Since these are critical factors for target-specific design and synthesis of more new-type CT complexes. To this end, theoretical investigations were performed in our group to answer these questions based on multiconfigurational perturbation theory. The photo-induced fluoroalkylation reactions are mediated by CT complexes, which are formed by the association of an acceptor of perfluoroalkyl halides RF−X (X = Br, I) and a suitable donor molecule such as β-naphtholate anion, were chosen as a paradigm example in this work. First, spectrum simulations were carried out by both CASPT2//CASSCF/PCM and TD-DFT/PCM methods. The computational results showed that the broadening spectra in visible light range (360-550nm) of the CT complexes originate from the 1(σπ*) excitation, accompanied by an intermolecular electron transfer, which was also found closely related to the aggregate states of the donor and acceptor. Moreover, from charge translocation analysis, the CT complex that showed larger charge transfer in the round state would exhibit smaller charge transfer in excited stated of 1(σπ*), causing blue shift relatively. Then, the excited-state potential energy surface (PES) was calculated at CASPT2//CASSCF(12,10)/ PCM level of theory to explore the photophysical properties of the CT complexes. The photo-induced C-X (X=I, Br) bond cleavage was found to occur in the triplet state, which is accessible through a fast intersystem crossing (ISC) process that is controlled by the strong spin-orbit coupling resulting from the heavy iodine and bromine atoms. Importantly, this rapid fragmentation process can compete and suppress the backward electron transfer (BET) event, facilitating the subsequent effective photochemical transformations. Finally, the reaction pathways of the radical coupling were also inspected, which showed that the radical chain propagation pathway could easy to accomplish with a small energy barrier no more than 3.0 kcal/mol, which is the key factor that promote the efficiency of the photochemical reactions induced by CT complexes. In conclusion, theoretical investigations were performed to explore the photophysical and photochemical properties of the CT complexes, as well as the mechanism of radical coupling reactions mediated by CT complex. The computational results and findings in this work can provide some critical insights into mechanism-based design for more new-type EDA complexes

Keywords: charge transfer complex, electron transfer, multiconfigurational perturbation theory, radical coupling

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Authors: Rajiv Kumar Srivastava

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Manufacturing of complex products such as automobiles and computers requires a very large number of parts and sub-assemblies. The design of mechanisms for delivery of these materials to the point of assembly is an important manufacturing system and supply chain challenge. Different approaches to this problem have been evolved for assembly lines designed to make large volumes of standardized products. However, contemporary assembly systems are required to concurrently produce a variety of products using approaches such as mixed model production, and at times even mass customization. In this paper we examine the material supply approaches for variety production in moderate to large volumes. The conventional approach for material delivery to high volume assembly lines is to supply and stock materials line-side. However for certain materials, especially when the same or similar items are used along the line, it is more convenient to supply materials in kits. Kitting becomes more preferable when lines concurrently produce multiple products in mixed model mode, since space requirements could increase as product/ part variety increases. At times such kits may travel along with the product, while in some situations it may be better to have delivery and station-specific kits rather than product-based kits. Further, in some mass customization situations it may even be better to have a single delivery and assembly station, to which an entire kit is delivered for fitment, rather than a normal assembly line. Finally, in low-moderate volume assembly such as in engineered machinery, it may be logistically more economical to gather materials in an order-specific kit prior to launching final assembly. We have studied material supply mechanisms to support assembly systems as observed in case studies of firms with different combinations of volume and variety/ customization. It is found that the appropriate approach tends to be a hybrid between direct line supply and different kitting modes, with the best mix being a function of the manufacturing and supply chain environment, as well as space and handling considerations. In our continuing work we are studying these scenarios further, through the use of descriptive models and progressing towards prescriptive models to help achieve the optimal approach, capturing the trade-offs between inventory, material handling, space, and efficient line supply.

Keywords: assembly systems, kitting, material supply, variety production

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Authors: S. K. Thind, Aparjot Kaur

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Heat stress is one of the major environmental factors drastically reducing wheat production. Crop heat tolerance can be enhanced by preconditioning of plants by exogenous application of osmoprotectants. Presently, the effect of trehalose pretreatment (at 1 mM, and 1.5 nM) under heat stress of 35±2˚C (moderate) and 40±2˚ (severe) for four and eight hour was conducted in wheat (Tricticum aestivum L.) genotypes viz. HD2967, PBW 175, PBW 343, PBW 621, and PBW 590. Heat stress affects wide spectrum of physiological processes within plants that are irreversibly damaged by stress. Membrane thermal stability (MTS) and cell viability was significantly decreased under heat stress for eight hours. Pretreatment with trehalose improved MTS and cell viability under stress and this effect was more promotory with higher concentration. Thermal stability of photosynthetic apparatus differed markedly between genotypes and Hill reaction activity was recorded more in PBW621 followed by C306 as compared with others. In all genotypes photolysis of water showed decline with increase in temperature stress. Trehalose pretreatment helped in sustaining Hill reaction activity probably by stabilizing the photosynthetic apparatus against heat-induced photo inhibition. Both plant growth and development were affected by temperature in both shoot and root under heat stress. The reduction was compensated partially by trehalose (1.5 mM) application. Adaption to heat stress is associated with the metabolic adjustment which led to accumulation of soluble sugars including non-reducing and reducing for their role in adaptive mechanism. Higher acid invertase activity in shoot of tolerant genotypes appeared to be a characteristic for stress tolerance. As sucrose synthase play central role in sink strength and in studied wheat genotype was positively related to dry matter accumulation. The duration of heat stress for eight hours had more severe effect on these parameters and trehalose application at 1.5 mM ameliorated it to certain extent.

Keywords: heat stress, Triticum aestivum, trehalose, membrane thermal stability, triphenyl tetrazolium chloride, reduction test, growth, sugar metabolism

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Authors: Christian Neunzig, Simon Fahle, Jürgen Schulz, Matthias Möller, Bernd Kuhlenkötter

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The increasing use of deep learning applications in production is becoming a competitive advantage. Predictive quality enables the assurance of product quality by using data-driven forecasts via machine learning models as a basis for decisions on test results. The use of real Bosch production data along the value chain of hydraulic valves is a promising approach to classifying the leakage of directional valves.

Keywords: artificial neural networks, classification, hydraulics, predictive quality, deep learning

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Authors: Chedly Tizaoui, Hussain Mohammed, Lobna Mansouri, Nidal Hilal, Latifa Bousselmi

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The degradation of diethyl phthalate (DEP) was studied using heterogeneous catalytic ozonation. Activated carbon was used as a catalyst. The degradation of DEP with ozone alone was slow while catalytic ozonation increased degradation rates. Second-order reaction kinetics was used to describe the experimental data, and the corresponding rate constant values were 1.19 and 3.94 M-1.s-1 for ozone and ozone/activated carbon respectively.

Keywords: ozone, heterogeneous catalytic ozonation, diethyl phthalate, endocrine disrupting chemicals

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Authors: Jonjaua Ranogajec, Ognjen Rudic, Snezana Pasalic, Snezana Vucetic, Damir Cjepa

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The paper involves a chain of activities from synthesis, establishment of the methodology for characterization and testing of novel protective materials through the pilot production and application on model supports. It summarizes the results regarding the development of the pilot production protocol for newly developed self-cleaning materials. The optimization of the production parameters was completed in order to improve the most important functional properties (mineralogy characteristics, particle size, self-cleaning properties and photocatalytic activity) of the newly designed nanocomposite material.

Keywords: pilot production, self-cleaning materials, compatibility, cultural heritage

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Authors: Jitlada Chumee, Drenpen Seeburin

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The cellulose was extracted from pomelo peel and an etherification reaction used for converting cellulose to carboxymethyl cellulose (CMC). The pomelo peel was refluxed with 0.5 M HCl and 1 M NaOH solution at 90°C for 1 h and 2 h, respectively. The cellulose was bleached with calcium hypochlorite and used as precursor. The precursor was soaked in mixed solution between isopropyl alcohol and 40%w/v NaOH for 12 h. After that, chloroacetic acid was added and reacted at 55°C for 6 h. The optimum condition was 5 g of cellulose: 0.25 mole of NaOH : 0.07 mole of ClCH2COOH with 78.00% of yield. Moreover, the product had 0.54 of degree of substitution (DS).

Keywords: pomelo peel, carboxymethyl cellulose, bioplastic, extraction

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Authors: Pinar Erturk, Sevde Altuntas, Fatih Buyukserin

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In order to obtain an effective integration between an implant and a bone, implant surfaces should have similar properties to bone tissue surfaces. Especially mimicry of the chemical, mechanical and topographic properties of the implant to the bone is crucial for fast and effective osseointegration. Titanium-based biomaterials are more preferred in clinical use, and there are studies of coating these implants with oxide layers that have chemical/nanotopographic properties stimulating cell interactions for enhanced osseointegration. There are low success rates of current implantations, especially in craniofacial implant applications, which are large and vital zones, and the oxide layer coating increases bone-implant integration providing long-lasting implants without requiring revision surgery. Our aim in this study is to examine bone-cell behavior on titanium implants with an aluminum oxide layer (AAO) on effective osseointegration potential in the deformation of large zones with difficult spontaneous healing. In our study, aluminum layer coated titanium surfaces were anodized in sulfuric, phosphoric, and oxalic acid, which are the most common used AAO anodization electrolytes. After morphologic, chemical, and mechanical tests on AAO coated Ti substrates, viability, adhesion, and mineralization of adult bone cells on these substrates were analyzed. Besides with atomic layer deposition (ALD) as a sensitive and conformal technique, these surfaces were coated with pure alumina (5 nm); thus, cell studies were performed on ALD-coated nanoporous oxide layers with suppressed ionic content too. Lastly, in order to investigate the effect of the topography on the cell behavior, flat non-porous alumina layers on silicon wafers formed by ALD were compared with the porous ones. Cell viability ratio was similar between anodized surfaces, but pure alumina coated titanium and anodized surfaces showed a higher viability ratio compared to bare titanium and bare anodized ones. Alumina coated titanium surfaces, which anodized in phosphoric acid, showed significantly different mineralization ratios after 21 days over other bare titanium and titanium surfaces which anodized in other electrolytes. Bare titanium was the second surface that had the highest mineralization ratio. Otherwise, titanium, which is anodized in oxalic acid electrolyte, demonstrated the lowest mineralization. No significant difference was shown between bare titanium and anodized surfaces except AAO titanium surface anodized in phosphoric acid. Currently, osteogenic activities of these cells on the genetic level are investigated by quantitative real-time polymerase chain reaction (qRT-PCR) analysis results of RUNX-2, VEGF, OPG, and osteopontin genes. Also, as a result of the activities of the genes mentioned before, Western Blot will be used for protein detection. Acknowledgment: The project is supported by The Scientific and Technological Research Council of Turkey.

Keywords: alumina, craniofacial implant, MG-63 cell line, osseointegration, oxalic acid, phosphoric acid, sulphuric acid, titanium

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Authors: Heba M. Saad Eldien, Ola Abdel-Tawab Hussein, Ahmed Yassein Nassar

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Background: Indomethacin is a non-steroidal anti inflammatory drug. Indomethacin induces an injury to gastrointestinal mucosa in experimental animals and humans and their use is associated with a significant risk of hemorrhage, erosions and perforation of both gastric and intestinal ulcers. The anti-inflammatory action of copper complexes is an important activity of their anti-ulcer effect achieved by their intermediary role as a transport form of copper that allow activation of the several copper-dependent enzymes. Therefore, several copper complexes were synthesized and investigated as promising alternative anti-ulcer therapy. Aim of the work: The purpose of this study was to evaluate a copper chelating complex consisting of egg albumin and copper as one of the copper peptides that can be used as anti-inflammatory agent and effective in ameliorates the hazards of the indomethacin on the histological structure of the fundus of the stomach that could be added to raise the efficacy of the currently used simple and cheap gastric anti-inflammatory drug mucogel. Material &methods: This study was carried out on 40 adult male albino rats,divided equally into 4 groups;Group I(control group) received distilled water,Group II(indomethacin treated group) received (25 mg/kg body weight, oral intubation) once, Group III (mucogel treated group)2 mL/rat once daily, oral incubation, Group IV(copper complex group) 1 mL /rat of 30 gm of copper albumin complex was mixed uniformly with mucogel to 100 mL. Treatment has been started six hour after Induction of Ulcers and continued till the 3rd day. The animals sacrificed and was processed for light, transmission electron microscopy(TEM) and immunostaining for inducible nitric oxide synthase(iNOS). Results: Fundic mucosa of group II, showed exfoliation of epithelial cells lining the gland, discontinuity of surface epithelial cells (ulcer formation), vacuolation and detachment of cells, eosinophilic infiltration and congestion of blood vessels in the lamina propria and submucosa. There was thickening and disarrangement of mucosa, weak positive reaction for PAS and marked increase in the collagen fibers lamina propria and the submucosa of the fundus. TEM revealed degeneration of cheif and parietal cells.Marked increase positive reactive of iNOS in all cells of the fundic gland. Group III showed reconstruction of gastric gland with cystic dilatation and vacuolation, moderate decrease of collagen fibers, reduced the intensity of iNOS while in Group IV healthy mucosa with normal surface lining epithelium and fundic glands, strong positive reaction for PAS, marked decrease of collagen fibers and positive reaction for iNOS. TEM revealed regeneration of cheif and parietal cells. Conclusion: Co treatment of copper-albumin complex seems to be useful for gastric ulcer treatment and ameliorates most of hazards of indomethacin.

Keywords: copper complex, gastric ulcer, indomethacin, rat

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Authors: Li-Jun Ren, Wei Pan, Li-Li Xu, Shu-Qing An

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This study evaluated whether different matrix composition volume ratio can improve water quality in the experiment. The mechanism and adsorption capability of wetland matrixes (oyster shell, coarse slag, and volcanic rock) and their different volume ratio in group configuration during pollutants removal processes were tested. When conditions unchanged, the residence time affects the reaction effect. The average removal efficiencies of four kinds of matrix volume ratio on the TN were 62.76%, 61.54%, 64.13%, and 55.89%, respectively.

Keywords: hydraulic residence time, matrix composition, removal efficiency, volume ratio

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Authors: Leo Nnamdi Ozurumba-Dwight

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Single-cell genomic analytical systems have proved to be a platform to isolate bulk cells into selected single cells for genomic, proteomic, and related metabolomic studies. This is enabling systematic investigations of the level of heterogeneity in a diverse and wide pool of cell populations. Single cell technologies, embracing techniques such as high parameter flow cytometry, single-cell sequencing, and high-resolution images are playing vital roles in these investigations on messenger ribonucleic acid (mRNA) molecules and related gene expressions in tracking the nature and course of disease conditions. This entails targeted molecular investigations on unit cells that help us understand cell behavoiur and expressions, which can be examined for their health implications on the health state of patients. One of the vital good sides of single-cell RNA sequencing (scRNA seq) is its probing capacity to detect deranged or abnormal cell populations present within homogenously perceived pooled cells, which would have evaded cursory screening on the pooled cell populations of biological samples obtained as part of diagnostic procedures. Despite conduction of just single-cell transcriptome analysis, scRNAseq now permits comparison of the transcriptome of the individual cells, which can be evaluated for gene expressional patterns that depict areas of heterogeneity with pharmaceutical drug discovery and clinical treatment applications. It is vital to strictly work through the tools of investigations from wet lab to bioinformatics and computational tooled analyses. In the precise steps for scRNAseq, it is critical to do thorough and effective isolation of viable single cells from the tissues of interest using dependable techniques (such as FACS) before proceeding to lysis, as this enhances the appropriate picking of quality mRNA molecules for subsequent sequencing (such as by the use of Polymerase Chain Reaction machine). Interestingly, scRNAseq can be deployed to analyze various types of biological samples such as embryos, nervous systems, tumour cells, stem cells, lymphocytes, and haematopoietic cells. In haematopoietic cells, it can be used to stratify acute myeloid leukemia patterns in patients, sorting them out into cohorts that enable re-modeling of treatment regimens based on stratified presentations. In immunotherapy, it can furnish specialist clinician-immunologist with tools to re-model treatment for each patient, an attribute of precision medicine. Finally, the good predictive attribute of scRNAseq can help reduce the cost of treatment for patients, thus attracting more patients who would have otherwise been discouraged from seeking quality clinical consultation help due to perceived high cost. This is a positive paradigm shift for patients’ attitudes primed towards seeking treatment.

Keywords: immunotherapy, transcriptome, re-modeling, mRNA, scRNA-seq

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Authors: Giorgi Goguadze, Jakub Zajączkowski

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This paper is written due to overview the connection between fragile states and non-state actors, we should take into account that fragile states may vary from weak, failing and failed. In this paper we will discuss about two countries, one of them is weak (Colombia/ second one is already failed- Somalia. We will try to understand what feeds ill non-state actors such as: terrorist organizations, criminal entities and other cells in these countries, what threats are they representing and how to eliminate these dangers in both national and international scope. This paper is mainly based on literature overview and personal attitude and doesn’t claim to be in scientific chain.

Keywords: fragile States, terrorism, tribalism, Somalia

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Authors: Galatee Levadoux, Trevor Benson, Chris Worrall

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With the rise of public awareness on climate change comes an increasing demand for renewable sources of energy. As a result, the wind power sector is striving to manufacture longer, more efficient and reliable wind turbine blades. Currently, one of the leading causes of blade failure in service is improper cure of the resin during manufacture. The infusion process creating the main part of the composite blade structure remains a critical step that is yet to be monitored in real time. This stage consists of a viscous resin being drawn into a mould under vacuum, then undergoing a curing reaction until solidification. Successful infusion assumes the resin fills all the voids and cures completely. Given that the electrical properties of the resin change significantly during its solidification, both the filling of the mould and the curing reaction are susceptible to be followed using dieletrometry. However, industrially available dielectrics sensors are currently too small to monitor the entire surface of a wind turbine blade. The aim of the present research project is to scale up the dielectric sensor technology and develop a device able to monitor the manufacturing process of large composite structures, assessing the conformity of the blade before it even comes out of the mould. An array of flat copper wires acting as electrodes are embedded in a polymer matrix fixed in an infusion mould. A multi-frequency analysis from 1 Hz to 10 kHz is performed during the filling of the mould with an epoxy resin and the hardening of the said resin. By following the variations of the complex admittance Y*, the filling of the mould and curing process are monitored. Results are compared to numerical simulations of the sensor in order to validate a virtual cure-monitoring system. The results obtained by drawing glycerol on top of the copper sensor displayed a linear relation between the wetted length of the sensor and the complex admittance measured. Drawing epoxy resin on top of the sensor and letting it cure at room temperature for 24 hours has provided characteristic curves obtained when conventional interdigitated sensor are used to follow the same reaction. The response from the developed sensor has shown the different stages of the polymerization of the resin, validating the geometry of the prototype. The model created and analysed using COMSOL has shown that the dielectric cure process can be simulated, so long as a sufficient time and temperature dependent material properties can be determined. The model can be used to help design larger sensors suitable for use with full-sized blades. The preliminary results obtained with the sensor prototype indicate that the infusion and curing process of an epoxy resin can be followed with the chosen configuration on a scale of several decimeters. Further work is to be devoted to studying the influence of the sensor geometry and the infusion parameters on the results obtained. Ultimately, the aim is to develop a larger scale sensor able to monitor the flow and cure of large composite panels industrially.

Keywords: composite manufacture, dieletrometry, epoxy, resin infusion, wind turbine blades

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Authors: Khadijeh Abhari, Seyed Shahram Shekarforoush, Saeid Hosseinzadeh

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Probiotics have been considered as an approach to treat and prevent a wide range of inflammatory diseases. The spore forming probiotic strain Bacillus coagulans has demonstrated anti-inflammatory and immune-modulating effects in both animals and humans. The prebiotic, inulin, also potentially affects the immune system as a result of the change in the composition or fermentation profile of the gastrointestinal microbiota. An in vivo trial was conducted to evaluate the effects of probiotic B. coagulans, and inulin, either separately or in combination, on down regulate immune responses and progression of rheumatoid arthritis using induced arthritis rat model. Forty-eight male Wistar rats were randomly divided into 6 groups and fed as follow: 1) control: Normal healthy rats fed by standard diet, 2) Disease control (RA): Arthritic induced (RA) rats fed by standard diet, 3) Prebiotic (PRE): RA+ 5% w/w long chain inulin, 4) Probiotic (PRO): RA+ 109 spores/day B. coagulans by orogastric gavage, 5) Synbiotic (SYN): RA+ 5% w/w long chain inulin and 109 spores/day B. coagulans and 6) Treatment control: (INDO): RA+ 3 mg/kg/day indomethacin by orogastric gavage. Feeding with mentioned diets started on day 0 and continued to the end of study. On day 14, rats were injected with complete Freund’s adjuvant (CFA) to induce arthritis. Arthritis activity was evaluated by biochemical parameters and paw thickness. Biochemical assay for Fibrinogen (Fn), Serum Amyloid A (SAA), TNF-α and Alpha-1-acid glycoprotein (α1AGp) was performed on day 21, 28 and 35 (1, 2 and 3 weeks post RA induction). Pretreatment with PRE, PRO and SYN diets significantly inhibit SAA and Fn production in arthritic rats (P < 0.001). A significant decrease in production of pro-inflammatory cytokines, TNF-α, was seen in PRE, PRO and SYN groups (P < 0.001) which was similar to the effect of the anti-inflammatory drug Indomethacin. Further, there were no significant anti-inflammatory effects observed following different treatments using α1AGp as a RA indicator. Pretreatment with all supplied diets significantly inhibited the development of paw swelling induced by CFA (P < 0.001). Conclusion: Results of this study support that oral intake of probiotic B. coagulans and inulin are able to improve biochemical and clinical parameters of induced RA in rat.

Keywords: rheumatoid arthritis, bacillus coagulans, inulin, animal model

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Authors: Anita Bajpai, Sarah Duan, Ashlee Erskine, Shehzein Khan, Raymond Kramer

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Introduction: This research focuses on exploring the beneficial effects if any, of Vitamin-D in reducing the need for supplemental oxygen among hospitalized COVID-19 patients. Two questions are investigated – Q1)Doeshaving a healthy level of baselineVitamin-D 25-OH (≥ 30ng/ml) help,andQ2) does administering Vitamin-D therapy after-the-factduring inpatient hospitalization help? Methods/Study Design: This is a comprehensive, retrospective, observational study of all inpatients at RUHS from March through December 2020 who tested positive for COVID-19 based on real-time reverse transcriptase–polymerase chain reaction assay of nasal and pharyngeal swabs and rapid assay antigen test. To address Q1, we looked atall N1=182 patients whose baseline plasma Vitamin-D 25-OH was known and who needed supplemental oxygen. Of this, a total of 121 patients had a healthy Vitamin-D level of ≥30 ng/mlwhile the remaining 61 patients had low or borderline (≤ 29.9ng/ml)level. Similarly, for Q2, we looked at a total of N2=893 patients who were given supplemental oxygen, of which713 were not given Vitamin-D and 180 were given Vitamin-D therapy. The numerical value of the maximum amount of oxygen flow rate(dependent variable) administered was recorded for each patient. The mean values and associated standard deviations for each group were calculated. Thesetwo sets of independent data served as the basis for independent, two-sample t-Test statistical analysis. To be accommodative of any reasonable benefitof Vitamin-D, ap-value of 0.10(α< 10%) was set as the cutoff point for statistical significance. Results: Given the large sample sizes, the calculated statistical power for both our studies exceeded the customary norm of 80% or better (β< 0.2). For Q1, the mean value for maximumoxygen flow rate for the group with healthybaseline level of Vitamin-D was 8.6 L/min vs.12.6L/min for those with low or borderline levels, yielding a p-value of 0.07 (p < 0.10) with the conclusion that those with a healthy level of baseline Vitamin-D needed statistically significant lower levels of supplemental oxygen. ForQ2, the mean value for a maximum oxygen flow rate for those not administered Vitamin-Dwas 12.5 L/min vs.12.8L/min for those given Vitamin-D, yielding a p-valueof 0.87 (p > 0.10). We thereforeconcludedthat there was no statistically significant difference in the use of oxygen therapy between those who were or were not administered Vitamin-D after-the-fact in the hospital. Discussion/Conclusion: We found that patients who had healthy levels of Vitamin-D at baseline needed statistically significant lower levels of supplemental oxygen. Vitamin-D is well documented, including in a recent article in the Lancet, for its anti-inflammatory role as an adjuvant in the regulation of cytokines and immune cells. Interestingly, we found no statistically significant advantage for giving Vitamin-D to hospitalized patients. It may be a case of “too little too late”. A randomized clinical trial reported in JAMA also did not find any reduction in hospital stay of patients given Vitamin-D. Such conclusions come with a caveat that any delayed marginal benefits may not have materialized promptly in the presence of a significant inflammatory condition. Since Vitamin-D is a low-cost, low-risk option, it may still be useful on an inpatient basis until more definitive findings are established.

Keywords: COVID-19, vitamin-D, supplemental oxygen, vitamin-D in primary care

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Authors: Anahita Mortazavi Manesh, Mojtaba Bagherzadeh

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Metalloporphyrins are well known to mimic the activity of monooxygenase enzymes. In this regard, metalloporphyrin complexes have been largely employed as valuable biomimetic catalysts, owing to the critical roles they play in oxygen transfer processes in catalytic oxidation reactions. Investigating in this area is based on different strategies to design selective, stable and high turnover catalytic systems. Immobilization of expensive metalloporphyrin catalysts onto supports appears to be a good way to improve their stability, selectivity and the catalytic performance because of the support environment and other advantages with respect to recovery, reuse. In other words, supporting metalloporphyrins provides a physical separation of active sites, thus minimizing catalyst self-destruction and dimerization of unhindered metalloporphyrins. Furthermore, heterogeneous catalytic oxidations have become an important target since their process are used in industry, helping to minimize the problems of industrial waste treatment. Hence, the immobilization of these biomimetic catalysts is much desired. An attractive approach is the preparation of the heterogeneous catalyst involves immobilization of complexes on silica coated magnetic nano-particles. Fe3O4@SiO2 magnetic nanoparticles have been studied extensively due to their superparamagnetism property, large surface area to volume ratio and easy functionalization. Using heterogenized homogeneous catalysts is an attractive option to facile separation of catalyst, simplified product work-up and continuity of catalytic system. Homogeneous catalysts immobilized on magnetic nanoparticles (MNPs) surface occupy a unique position due to combining the advantages of both homogeneous and heterogeneous catalysts. In addition, superparamagnetic nature of MNPs enable very simple separation of the immobilized catalysts from the reaction mixture using an external magnet. In the present work, an efficient heterogeneous catalyst was prepared by immobilizing manganese porphyrin on functionalized magnetic nanoparticles through the amino propyl linkage. The prepared catalyst was characterized by elemental analysis, FT-IR spectroscopy, X-ray powder diffraction, atomic absorption spectroscopy, UV-Vis spectroscopy, and scanning electron microscopy. Application of immobilized metalloporphyrin in the oxidation of various organic substrates was explored using Gas chromatographic (GC) analyses. The results showed that the supported Mn-porphyrin catalyst (Fe3O4@SiO2-NH2@MnPor) is an efficient and reusable catalyst in oxidation reactions. Our catalytic system exhibits high catalytic activity in terms of turnover number (TON) and reaction conditions. Leaching and recycling experiments revealed that nanocatalyst can be recovered several times without loss of activity and magnetic properties. The most important advantage of this heterogenized catalytic system is the simplicity of the catalyst separation in which the catalyst can be separated from the reaction mixture by applying a magnet. Furthermore, the separation and reuse of the magnetic Fe3O4 nanoparticles were very effective and economical.

Keywords: Fe3O4 nanoparticle, immobilized metalloporphyrin, magnetically separable nanocatalyst, oxidation reactions

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Authors: Thulane Paepae, Tumisang Seodigeng

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This paper demonstrates the use of a method of synthesizing process flowsheets using a graphical tool called the GH-plot and in particular, to look at how it can be used to compare the reactions of a combined simultaneous process with regard to their thermodynamics. The technique uses fundamental thermodynamic principles to allow the mass, energy and work balances locate the attainable region for chemical processes in a reactor. This provides guidance on what design decisions would be best suited to developing new processes that are more effective and make lower demands on raw material and energy usage.

Keywords: attainable regions, dimethyl ether, optimal reaction network, GH Space

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Authors: Y. El Kaissi, M. Allam, A. Koulou, M. Galai, M. Ebn Touhami

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The aim of our work is to develop an industrial bath of nickel alloy deposit on mild steel. The optimization of the operating parameters made it possible to obtain a stable Ni-P alloy deposition formulation. To understand the reaction mechanism of the deposition process, a kinetic study was performed by cyclic voltammetry and by electrochemical impedance spectroscopy (EIS). The coatings obtained have a very high corrosion resistance in a very aggressive acid medium which increases with the heat treatment.

Keywords: cyclic voltammetry, EIS, electroless Ni–P coating, heat treatment, potentiodynamic polarization

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Authors: Yousef Abu Amrieh

Abstract:

This paper explores how Arab American novelist Rabih Alameddine's recent novel The Angel of History (2016) appropriates certain motifs, tropes, and themes from Shakespeare's The Tempest. In particular, Alameddine's novel re-tells the story of Caliban and his mother from the perspective of a Yemeni bastard whose mis/fortunes take him to the US shores in the eighties of the previous century. The novel, specifically, re-writes the scene in which Caliban is gazed at by European travelers like Stephano and Trinculo whose first reaction to seeing him is to consider how to sell him or give him as a gift when they safely return to Europe. The novel contests Shakespeare's representation of Caliban as 'marketable' through depicting his daily experiences in modern day America.

Keywords: appropriation, Alameddine, Shakespeare, The Tempest

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