Search results for: membrane resistance

Authors: Asif Jan

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Sodium hypochlorite (NaClO) is a common cleaning agent for ultrafiltration (UF) membranes. While its detrimental effects on polymeric membranes are well-documented, its impact on ceramic membranes remains less explored. This study investigates the chemical stability of silicon carbide (SiC) UF membranes prepared using low-pressure chemical vapor deposition (LP-CVD) during prolonged NaClO exposure. SiC UF membranes were fabricated via LP-CVD at two different temperature and pressure conditions. LP-CVD offers the advantage of SiC membrane fabrication at significantly lower temperatures (700-900°C) compared to conventional methods. The membranes were subjected to 200 hours of NaClO aging to assess their resilience. Before and after aging, we evaluated the properties and performance of the SiC UF membranes to identify optimal LP-CVD conditions. Our findings show that SiC UF membranes produced at 860°C via LP-CVD exhibit exceptional resistance to NaClO aging, whereas those prepared at 750°C experience significant deterioration. This highlights the crucial role of precise LP-CVD parameters in ensuring the robustness and long-term performance of SiC membranes in harsh chemical cleaning environments.

Keywords: ceramic membranes, ultrafiltration membranes, wastewater treatment, chemical vapor deposition

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Authors: Sasan Mohammadi

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Due to our passion for coffee, we use 16 billion throwaway coffee cups yearly. Coffee lovers throughout the globe have discovered the hard way that their paper cups are not recyclable, despite what coffee businesses have repeatedly assured them [1] A disposable, single-use coffee cup comprises a paper and polyethylene layer. Polyethylene is a typical material used to fill a coffee cup's inside to keep its structure and provide water and heat resistance. In addition, the polyethylene layer prevents recycling since it is difficult to separate the plastic liner from the paper layer [2]. In addition, owing to the plastic membrane lining many of these cups, they cannot be recycled and may take up to 30 years to biodegrade [3]. Most of researcher try to separate plastic part ,but it is not economical and easy.For this purposes,it is not yet happen. In our research we don't separate plastic, just we make a homogeneous pulp with cold water.then fix it in mold and dry it,after completely drying cycle we heated the product in 100 degree of centigrade this cause a sintering effect by plastic particle between paper fibers.This method increase 30 percent the strength of product.This product has a good sound proof and thermal isolation. This means we can use it as insulator.with low density we can control the the density by percentage of air solved in pulp.

Keywords: recycling, disposable coffee cup, insolator, low density

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Authors: Andrew Freiburger, Sergi Molins

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Freshwater is a vital resource; yet, the supply of clean freshwater is diminishing as the consequence of melting snow and ice from global warming, pollution from industry, and an increasing demand from human population growth. The unsustainable trajectory of diminishing water resources is projected to jeopardize water security for billions of people in the 21st century. Membrane desalination technologies may resolve the growing discrepancy between supply and demand by filtering arbitrary feed water into a fraction of renewable, clean water and a fraction of highly concentrated brine. The leading hindrance of membrane desalination is fouling, whereby the highly concentrated brine solution encourages micro-organismal colonization and/or the precipitation of occlusive minerals (i.e. scale) upon the membrane surface. Thus, an understanding of brine formation is necessary to mitigate membrane fouling and to develop efficacious desalination technologies that can bolster the supply of available freshwater. This study presents a reactive transport simulation of brine formation and scale deposition during reverse osmosis (RO) desalination. The simulation conceptually represents the RO module as a one-dimensional domain, where feed water directionally enters the domain with a prescribed fluid velocity and is iteratively concentrated in the immobile layer of a dual porosity model. Geochemical PHREEQC code numerically evaluated the conceptual model with parameters for the BW30-400 RO module and for real water feed sources – e.g. the Red and Mediterranean seas, and produced waters from American oil-wells, based upon peer-review data. The presented simulation is computationally simpler, and hence less resource intensive, than the existent and more rigorous simulations of desalination phenomena, like TOUGHREACT. The end-user may readily prepare input files and execute simulations on a personal computer with open source software. The graphical results of fouling-potential and brine characteristics may therefore be particularly useful as the initial tool for screening candidate feed water sources and/or informing the selection of an RO module.

Keywords: desalination, PHREEQC, reactive transport, scaling

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Authors: Kumlachew Zelalem Walle, Chun-Chen Yang

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Solid-state Lithium metal batteries (SSLMBs) that contain polymer and ceramic solid electrolytes have received considerable attention as an alternative to substitute liquid electrolytes in lithium metal batteries (LMBs) for highly safe, excellent energy storage performance and stability under elevated temperature situations. Here, a novel fast Li-ion conducting material, LiTa₂PO₈ (LTPO), was synthesized and electrochemical performance of as-prepared powder and LTPO-incorporated composite solid polymer electrolyte (LTPO-CPE) membrane were investigated. The as-prepared LTPO powder was homogeneously dispersed in polymer matrices, and a hybrid solid electrolyte membrane was synthesized via a simple solution-casting method. The room temperature total ionic conductivity (σt) of the LTPO pellet and LTPO-CPE membrane were 0.14 and 0.57 mS cm-1, respectively. A coin battery with NCM811 cathode is cycled under 1C between 2.8 to 4.5 V at room temperature, achieving a Coulombic efficiency of 99.3% with capacity retention of 74.1% after 300 cycles. Similarly, the LFP cathode also delivered an excellent performance at 0.5C with an average Coulombic efficiency of 100% without virtually capacity loss (the maximum specific capacity is at 27th: 138 mAh g−1 and 500th: 131.3 mAh g−1). These results demonstrates the feasibility of a high Li-ion conductor LTPO as a filler, and the developed polymer/ceramic hybrid electrolyte has potential to be a high-performance electrolyte for high-voltage cathodes, which may provide a fresh platform for developing more advanced solid-state electrolytes.

Keywords: li-ion conductor, lithium-metal batteries, composite solid electrolytes, liTa2PO8, high-voltage cathode

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Authors: K. Jithendra Gowd, Ch. Sai Babu, S. Sivanagaraju

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Electric power systems are daily exposed to service interruption mainly due to faults and human accidental interference. Short circuit currents are responsible for several types of disturbances in power systems. The fault currents are high and the voltages are reduced at the time of fault. This paper presents two suitable methods, consideration of fault resistance and Distributed Generator are implemented and analyzed for the enhancement of voltage profile during fault conditions. Fault resistance is a critical parameter of electric power systems operation due to its stochastic nature. If not considered, this parameter may interfere in fault analysis studies and protection scheme efficiency. The effect of Distributed Generator is also considered. The proposed methods are tested on the IEEE 37 bus test systems and the results are compared.

Keywords: distributed generation, electrical distribution systems, fault resistance

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Authors: Nourhan Hussein Fanaki, Hoda Mohamed Gamal El-Din Omar, Nihal Kadry Moussa, Eva Adel Edward Farid

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The resistance of staphylococci to various antibiotics has become a major concern for health care professionals. The efficacy of the combinations of selected glycopeptides (vancomycin and teicoplanin) with gentamicin or rifampicin, as well as that of gentamicin/rifampicin combination, was studied against selected pathogenic staphylococcus isolated from Egypt. The molecular distribution of genes conferring resistance to these four antibiotics was detected among tested clinical isolates. Antibiotic combinations were studied using the checkerboard technique and the time-kill assay (in both the stationary and log phases). Induction of resistance to glycopeptides in staphylococci was tried in the absence and presence of diclofenac sodium as inducer. Transmission electron microscopy was used to study the effect of glycopeptides on the ultrastructure of the cell wall of staphylococci. Attempts were made to cure gentamicin resistance plasmids and to study the transfer of these plasmids by conjugation. Trials for the transformation of the successfully isolated gentamicin resistance plasmid to competent cells were carried out. The detection of genes conferring resistance to the tested antibiotics was performed using the polymerase chain reaction. The studied antibiotic combinations proved their efficacy, especially when tested during the log phase. Induction of resistance to glycopeptides in staphylococci was more promising in presence of diclofenac sodium, compared to its absence. Transmission electron microscopy revealed the thickening of bacterial cell wall in staphylococcus clinical isolates due to the presence of tested glycopeptides. Curing of gentamicin resistance plasmids was only successful in 2 out of 9 tested isolates, with a curing rate of 1 percent for each. Both isolates, when used as donors in conjugation experiments, yielded promising conjugation frequencies ranging between 5.4 X 10-2 and 7.48 X 10-2 colony forming unit/donor cells. Plasmid isolation was only successful in one out of the two tested isolates. However, low transformation efficiency (59.7 transformants/microgram plasmid DNA) of such plasmids was obtained. Negative regulators of autolysis, such as arlR, lytR and lrgB, as well as cell-wall associated genes, such as pbp4 and/or pbp2, were detected in staphylococcus isolates with reduced susceptibility to the tested glycopeptides. Concerning rifampicin resistance genes, rpoBstaph was detected in 75 percent of the tested staphylococcus isolates. It could be concluded that in vitro studies emphasized the usefulness of the combination of vancomycin or teicoplanin with gentamicin or rifampicin, as well as that of gentamicin with rifampicin, against staphylococci showing varying resistance patterns. However, further in vivo studies are required to ensure the safety and efficacy of such combinations. Diclofenac sodium can act as an inducer of resistance to glycopeptides in staphylococci. Cell-wall thickness is a major contributor to such resistance among them. Gentamicin resistance in these strains could be chromosomally or plasmid mediated. Multiple mutations in the rpoB gene could mediate staphylococcus resistance to rifampicin.

Keywords: glycopeptides, combinations, induction, diclofenac, transmission electron microscopy, polymerase chain reaction

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Authors: Yousef Naserzadeh, Niloufar Mahmoudi

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Oxidation resistance is one of the important parameters in maintaining the quality of olive oil during its storage. Ensuring the stability of the quality of olive oil is one of the important concerns of the producers and consumers. Prooxidants such as iron and copper accelerate the oxidation reaction, and also anti-oxidants and chelating compounds delay it. In this study, chelating effect of tea extract which contains significant amounts of tannic acid is investigated in comparison with citric acid. To do it, 0.1 ppm copper was added to these four kinds of oil, sunflower, olive, canola, and tallow, and then chelating effect of citric acid (0.01%), tannic acid (0.01%) and tea extract (0.1%) were measured by adding to this composition. To this end, the resistance time of the oils against oxidation was measured at 120 °C and an air flow of 20 liters per hour. And the value of peroxide was measured by oven test in six periods of 24 hours at 105 °C. The results showed that citric acid, tannic acid and tea extract had chelating property and increased the resistance time of the studied oils. As a result, considering chelating property and increasing resistance of oil, tannic acid showed better effect than tea extract and tea extract had better effect than citric acid.

Keywords: tannic acid, chelate, edible oils, black tea extract, TBHQ

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Authors: Ali Mardani-Aghabaglou, Zia Ahmad Faqiri, Semsi Yazici

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In this study, the effect of permeability reducing admixture (PRA) utilization on fresh properties, compressive strength and sulfate resistance of self-consolidating concrete (SSC) were investigated. For this aim, two different commercial PRA were used at two utilization ratios as %0.1 and %0.2 wt. CEM I 42.5 R type cement and crushed limestone aggregate having Dmax of 15 mm were used for preparing of SCC mixtures. In all mixtures, cement content, water/cement ratio, and flow value were kept constant as 450 kg, 0.40 and 65 ± 2 cm, respectively. In order to obtain desired flow value, a polycarboxylate ether-based high range water reducing admixture was used at different content. T50 flow time, flow value, L-box, and U-funnel of SCC mixture were measured as fresh properties. 1, 3, 7 and 28-day compressive strength of SCC mixture were obtained on 150 mm cubic specimens. To investigate the sulfate resistance of SCC mixture 75x75x285 mm prismatic specimens were produced. After 28-day water curing, specimens were immersed in %5 sodium sulfate solution during 210 days. The length change of specimens was measured at 5-day time intervals up to 210 days. According to the test results, all fresh properties of SCC mixtures were in accordance with the European federation of specialist construction chemicals and concrete systems (EFNARC) critter for SCC mixtures. The utilization of PRA had no significant effect on compressive strength and fresh properties of SCC mixtures. Regardless of PRA type, sulfate resistance of SCC mixture increased by adding of PRA into the SCC mixtures. The length changes of the SCC mixtures containing %1 and %2 PRA were measured as %8 and %14 less than that of control mixture containing no PRA, respectively.

Keywords: permeability reducing admixture, self-consolidating concrete, fresh properties, sulfate resistance

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Authors: Jose D. Zapata-Torres, Esteban Naranjo-Gutiérrez, Angela M. Martínez-Valencia, Jenny J. Chaparro-Gutiérrez, David Villar-Argaiz

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Reports of drug resistance have been made in every livestock host and to every anthelmintic class. In some regions of world, the extremely high prevalence of multi-drug resistance in nematodes of sheep and goats threatens the viability of small-ruminant industries. In the region of Antioquia, Colombia, no reports of nematode resistance have been documented due to a lack of veterinary diagnostic laboratories. The objective of this study was to evaluate the efficacy of albendazole, fenbendazole, and levamisole to control gastrointestinal nematodes in goat farms of Antioquia by doing fecal egg count reduction tests. A total of 139 crossbreed goats from four separate farms were sampled for feces prior to, and 14 days following anthelmintc treatments. Individual fecal egg counts were performed using the modified three chamber McMaster technique. The anthelmintics administered at day 0 were albendazole (farm 1, n=63), fenbendazole (farm 2, n=20), and levamisole (farm 3 and 4, n= 37, and 19). Larval cultures were used to identify the genus of nematodes using Baermann`s technique and the morphological keys for identification of L3 in small ruminants. There was no difference in fecal egg counts between 0 and 14, with means (±SD) of 1681,5 ± 2121,5 and 1715,12 ± 1895,4 epg (eggs per gram), respectively. The egg count reductions for each anthelmintic and farm were 25,86% for albendazole (farm 1), 0% for fenbendazole (farm 2), 0% (farm 3), and 5,5% (farm 4) for levamisole. The genus of nematodes identified was predominantly Haemonchus spp., with 70,27% and 82,81% for samples from day 0 and 14, respectively. These results provide evidence of a total state of resistance to 3 common anthelmintics. Further research is needed to design integrate management programs to control nematodes in small ruminants in Colombia.

Keywords: anthelmintics, goat, haemonchus, resistance

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Authors: M. Keršič, M. Lužnik, J. Lužnik

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Cervical dilatation and membrane herniation before 26th week of gestation poses very high risk for extremely and very premature childbirth. Cerclage with mesh cap (mesh cerclage, MC) can greatly diminish this risk and provide additional positive effects. Between 2005 and 2014, MC has been performed in 9 patients with singleton pregnancies who had prolapsed membranes beyond external cervical/uterine os before 25th week of pregnancy (one in 29th). With patients in general anaesthesia, lithotomy and Trendelenburg position (about 25°) prolapsed membranes were repositioned in the uterine cavity, using tampon soaked in antiseptic solution (Skinsept mucosa). A circular, a type of purse-string suture (main band) with double string Ethilon 1 was applied at about 1 to 1.5 cm from the border of the external uterine os - 6 to 8 stitches were placed, so the whole external uterine os was encircled (modified McDonald). In the next step additional Ethilon 0 sutures were placed around all exposed parts of the main double circular suture and loosely tightened. On those sutures, round tailored (diameter around 6 cm) mesh (Prolene® or Gynemesh* PS) was attached. In all 9 cases, gestation was prolonged on average for 9 weeks and 4 days (67 days). In four cases maturity was achieved. Mesh was removed in 37th–38th week of pregnancy or if spontaneous labour began. In two cases, a caesarean section was performed because of breech presentation. In the first week after birth in 22nd week one new born died because of immaturity (premature birth was threatening in 18th week and then MC was placed). Ten years after first MC, 8 of 9 women with singleton pregnancy and MC performed have 8 healthy children from these pregnancies. Mesh cerclage successfully closed the opened cervical canal or uterine orifice and prevented further membrane herniation and membrane rupture. MC also provides a similar effect as with occluding the external os with suturing but without interrupting the way for excretion of abundant cervical mucus. The mesh also pulls the main circular band outwards and thus lowers the chance of suture cutting through the remaining cervix. MC prolonged gestation very successfully (mean for 9 weeks and 4 days) and thus increased possibility for survival and diminished the risk for complications in very early preterm delivered survivors in cases with cervical dilatation and membrane herniation before 26th week of gestation. Without action possibility to achieve at least 28th or 32nd week of gestation would be poor.

Keywords: cervical insufficiency, mesh cerclage, membrane protrusion, premature birth prevention, physical exam-indicated cerclage, rescue cerclage

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Authors: Mohammed Hakim Jafferali, Balaje Vijayaraghavan, Ricardo A. Figueroa, Ellinor Crafoord, Veronica J. Larsson, Einar Hallberg, Santhosh Gudise

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The nuclear envelope which surrounds the chromatin of eukaryotic cells contains more than a hundred transmembrane proteins. Mutations in some genes encoding nuclear envelope proteins give rise to human diseases including neurological disorders. The function of many nuclear envelope proteins is not well established. This is partly because nuclear envelope proteins and their interactions are difficult to study due to the inherent resistance to extraction of nuclear envelope proteins. We have developed a novel method called MCLIP, to identify interacting partners of nuclear envelope proteins in live cells. Using MCLIP, we found three new binding partners of the inner nuclear membrane protein Samp1: the intermediate filament protein Lamin B1, the LINC complex protein Sun1 and the G-protein Ran. Furthermore, using in vitro studies, we show that Samp1 binds both Emerin and Ran directly. We have also studied the interaction between Samp1 and Ran in detail. The results show that the Samp1 binds stronger to RanGTP than RanGDP. Samp1 is the first transmembrane protein known to bind Ran and it is tempting to speculate that Samp1 may provide local binding sites for RanGTP at membranes.

Keywords: MCLIP, nuclear envelope, ran, Samp1

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Authors: Pompilia Buzatu, Hazim Qiblawey, Albert Odai, Jana Jamaleddin, Mustafa Nasser, Simon J. Judd

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Membrane bioreactor (MBR) technology is challenged by the tendency for the membrane permeability to decrease due to ‘clogging’. Clogging includes ‘sludging’, the filling of the membrane channels with sludge solids, and ‘ragging’, the aggregation of short filaments to form long rag-like particles. Both sludging and ragging demand manual intervention to clear out the solids, which is time-consuming, labour-intensive and potentially damaging to the membranes. These factors impact on costs more significantly than membrane surface fouling which, unlike clogging, is largely mitigated by the chemical clean. However, practical evaluation of MBR clogging has thus far been limited. This paper presents the results of recent work attempting to quantify sludging and clogging based on simple bench-scale tests. Results from a novel ragging simulation trial indicated that rags can be formed within 24-36 hours from dispersed < 5 mm-long filaments at concentrations of 5-10 mg/L under gently agitated conditions. Rag formation occurred for both a cotton wool standard and samples taken from an operating municipal MBR, with between 15% and 75% of the added fibrous material forming a single rag. The extent of rag formation depended both on the material type or origin – lint from laundering operations forming zero rags – and the filament length. Sludging rates were quantified using a bespoke parallel-channel test cell representing the membrane channels of an immersed flat sheet MBR. Sludge samples were provided from two local MBRs, one treating municipal and the other industrial effluent. Bulk sludge properties measured comprised mixed liquor suspended solids (MLSS) concentration, capillary suction time (CST), particle size, soluble COD (sCOD) and rheology (apparent viscosity μₐ vs shear rate γ). The fouling and sludging propensity of the sludge was determined using the test cell, ‘fouling’ being quantified as the pressure incline rate against flux via the flux step test (for which clogging was absent) and sludging by photographing the channel and processing the image to determine the ratio of the clogged to unclogged regions. A substantial difference in rheological and fouling behaviour was evident between the two sludge sources, the industrial sludge having a higher viscosity but less shear-thinning than the municipal. Fouling, as manifested by the pressure increase Δp/Δt, as a function of flux from classic flux-step experiments (where no clogging was evident), was more rapid for the industrial sludge. Across all samples of both sludge origins the expected trend of increased fouling propensity with increased CST and sCOD was demonstrated, whereas no correlation was observed between clogging rate and these parameters. The relative contribution of fouling and clogging was appraised by adjusting the clogging propensity via increasing the MLSS both with and without a commensurate increase in the COD. Results indicated that whereas for the municipal sludge the fouling propensity was affected by the increased sCOD, there was no associated increased in the sludging propensity (or cake formation). The clogging rate actually decreased on increasing the MLSS. Against this, for the industrial sludge the clogging rate dramatically increased with solids concentration despite a decrease in the soluble COD. From this was surmised that sludging did not relate to fouling.

Keywords: clogging, membrane bioreactors, ragging, sludge

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Authors: Tramuta Clara, Masotti Chiara, Pitti Monica, Adriano Daniela, Battistini Roberta, Serraca Laura, Decastelli Lucia

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Oysters are considered filter organisms, and their raw consumption may increase health risks for consumers: it is often associated with outbreaks of gastroenteritis or enteric illnesses. Most of these foodborne diseases are caused by Vibrio strains, enteric pathogens also involved in the diffusion of genetic determinants of antibiotic resistance and their entrance along the food chain. The European Food Safety Authority (EFSA), during the European Union report on antimicrobial resistance in 2017, focused the attention about the role of food as a possible carrier of antibiotic-resistant bacteria or antibiotic-resistance genes that determine health risks for humans. This study wants to determine antibiotic resistance and antibiotic-resistance genes in Vibrio spp. isolated from Crassostrea gigas oysters collected in the Golfo della Spezia (Liguria, Italy). A total of 47 Vibrio spp. strains were isolated (ISO21872-2:2017) during the summer of 2021 from oysters of Crassostrea gigas. The strains were identified by MALDI-TOF (Bruker, Germany) mass spectrometry and tested for antibiotic susceptibility using a broth microdiluition method (ISO20776-1:2019) using Sensititre EUVSEC plates (Thermo-Fisher Scientific) to obtain the Minimum Inhibitory Concentration (MIC). The strains were tested with PCR-based biomolecular methods, according to previous works, to define the presence of 23 resistance genes of the main classes of antibiotics used in human and veterinary medicine: tet (B), tet (C), tet (D), tet (A), tet (E), tet (G ), tet (K), tet (L), tet (M), tet (O), tet (S) (tetracycline resistance); blaCTX-M, blaTEM, blaOXA, blaSHV (β-lactam resistance); mcr-1 and mcr-2 (colistin resistance); qnrA, qnrB, and qnrS (quinolone resistance); sul1, sul2 and sul3 (sulfonamide resistance). Six different species have been identified: V. alginolyticus 34% (n=16), V. harveyi 28% (n=13), V. fortis 15% (n=7), V. pelagius 8% (n=4), V. parahaemolyticus 11% (n=5) e V. chagasii 4% (n=2). The PCR assays showed the presence of the blaTEM gene on 40% of the strains (n=19). All the other genes were not detected, except for a V. alginolyticus positive for anrS gene. The broth microdiluition method results showed an high level of resistance for ciprofloxacin (62%; n=29), ampicillin (47%; n=22), and colistin (49%; n=23). Furthermore, 32% (n=15) of strains can be considered multiresistant bacteria for the simultaneous presence of resistance for three different antibiotic classes. Susceptibility towards meropenem, azithromycin, gentamicin, ceftazidime, cefotaxime, chloramphenicol, tetracycline and sulphamethoxazole reached 100%. The Vibrio species identified in this study are widespread in marine environments and can cause gastrointerstinal infections after the ingestion of raw fish products and bivalve molluscs. The level of resistance to antibiotics such as ampicillin, ciprofloxacin and colistin can be connected to anthropic factors (industrial, agricultural and domestic wastes) that promote the spread of resistance to these antibiotics. It can be also observed a strong correlation between phenotypic (resistant MIC) and genotypic (positive blaTEM gene) resistance for ampicillin on the same strains, probably due to the transfer of genetic material between bacterial strains. Consumption of raw bivalve molluscs can represent a risk for consumers heath due to the potentially presence of foodborne pathogens, highly resistant to different antibiotics and source of transferable antibiotic-resistant genes.

Keywords: vibrio species, blaTEM genes, antimicrobial resistance, PCR

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Authors: Eric Bimmoy

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The aim of the study conducted inside screen house is to determine the effect of Vesicular Arbuscular Mycorrhiza MycoVAM Glomus mosseae or Glomus fasciculatum on the drought resistance of Betel nut (Areca catechu). The study revealed that there is a highly significant growth increment and drought resistance of planted seedling inoculated with VAM compared to uninoculated seedling. The study revealed not significant under well water condition after 60 days. Growths are higher in inoculated seedlings compared to uninoculated seedlings. Seventy days (75) days after planting there was a highly significant difference in inoculated plants. It is not significant in height increment after 90 days, although the height percentage increase in inoculated seedlings was higher. The water stressed Areca catechu seedlings inoculated with VAM significantly increases total shoot height with increment of 72.34 while days before wilting 65.89 and 88.68 in the leaf water content. This demonstrates the result provided by VAM in the development of seedlings.

Keywords: vesicular-arbuscular mycorrhiza MycoVAM, resistance, symbiosis, water stressed

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Authors: Zunnu Raen Akhtar, U. Irshad, M. Majid

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Due to the widespread cultivation of transgenic cotton, intense selection pressure resulted in resistant allele in pink bollworm, Pectinophora gossypiella (Gelechiidae: Lepidoptera). A resistant strain of pink bollworm against transgenic cotton has become a challenge to Integrated Resistance Management (IRM) in the World. Laboratory and field studies were conducted to determine the resistant strains of pink bollworm by performing bioassay, extracting the DNA, conducting PCR of both laboratory as well as field collected pink bollworms to observe the developed resistance. In all of the studies, two Bt varieties FH-142 and FH-118 expressing Cry1Ac compared to non-Bt (Control) were tested against pink bollworm. In the laboratory, bioassay results showed that there was no significant mortality difference between Bt and non-Bt varieties. Similar mortality percentage was observed in transgenic and non-transgenic (control) variety. Insects which were survived after bioassay, as well as those collected from the Bt cotton fields, were selected for further molecular studies. DNA extraction followed by PCR was conducted to check the resistant strains in pink bollworm. In field studies, we also observed the population dynamics of pink boll worms on Bt as compared to non-Bt varieties. Laboratory and field studies confirmed that resistant strains occurs in Pakistani Bt cotton fields. Different strategies should be adopted to combat that serious prevailing resistance issues.

Keywords: transgenic cotton, resistance, pectinophora gossypiella, , integrated resistance management (IRM), polymerase chain reaction (PCR)

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Authors: Marzieh Sayyad, Mohsen Salesi

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Metabolic syndrome (MetS), a collection of cardiometabolic risk factors, is linked to the development of cardiovascular disease (CVD) and diabetes. The prevalence of MetS is on the rise with more women affected than men. The goal of this study was to compare the effects of resistance and aerobic exercise training on metabolic syndrome components in non-athlete, middle-aged woman. 51 non-athlete overweight female participated voluntarily in this study. Participants were divided randomly into three groups including resistance, aerobic and control group (number of each group 17). 24 hours before the beginning of training program, the blood sample was taken in fasting state. The two training groups participated in sport activities for eight weeks, three times a week duration 60-90 minutes. Two days following the end of the 8th week, all the measurements were performed similar to the pretest phase. The data was analyzed using one-way analysis of variance. The results showed that aerobic exercise training significantly decreased weight (p=.05), triglyceride (p<0.01) and systolic blood pressure (p<0.02) and HDL-c (p<0.01) was significantly increased. Also in resistance exercise training group TG decreased significantly (p<0.01) and HDL-c (p<0.05) was significantly increased. This study demonstrated that a regular physical activity program improved several metabolic and physiological parameters in healthy, previously sedentary subjects with the metabolic syndrome. In conclusion, it seems that this type of training can be efficient, safe and inexpensive way in order to reduce and prevent metabolic syndrome.

Keywords: aerobic exercise, metabolic syndrome, overweight sedentary female, resistance exercise

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Authors: Sadao Araki, Daisuke Gondo, Satoshi Imasaka, Hideki Yamamoto

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The separation of organic compounds from aqueous solutions is a key technology for recycling valuable organic compounds and for the treatment of wastewater. The wastewater from chemical plants often contains organic compounds such as ethyl acetate (EA), methylethyl ketone (MEK) and isopropyl alcohol (IPA). In this study, we prepared hydrophobic silica membranes by a sol-gel method. We used phenyltrimethoxysilane (PhTMS), ethyltrimethoxysilan (ETMS), Propyltrimethoxysilane (PrTMS), N-butyltrimethoxysilane (BTMS), N-Hexyltrimethoxysilane (HTMS) as silica sources to introduce each functional groups on the membrane surface. Cetyltrimethyl ammonium bromide (CTAB) was used as a molecular template to create suitable pore that enable the permeation of organic compounds. These membranes with five different functional groups were characterized by SEM, FT-IR, and permporometry. Thicknesses and pore diameters of silica layer for all membrane were about 1.0 μm and about 1 nm, respectively. In other words, functional groups had an insignificant effect on the membrane thicknesses and the formation of the pore by CTAB. We confirmed the effect of functional groups on the flux and separation factor for ethyl acetate (EA), methyl ethyl ketone, acetone and 1-butanol (1-BtOH) /water mixtures. All membranes showed a high flux for ethyl acetate compared with other compounds. In particular, the hydrophobic silica membrane prepared by using BTMS showed 0.75 kg m-2 h-1 of flux for EA. For all membranes, the fluxes of organic compounds showed the large values in the order corresponding to EA > MEK > acetone > 1-BtOH. On the other hand, carbon chain length of functional groups among ETMS, PrTMS, BTMS, PrTMS and HTMS did not have a major effect on the organic flux. Although we confirmed the relationship between organic fluxes and organic molecular diameters or fugacity of organic compounds, these factors had a low correlation with organic fluxes. It is considered that these factors affect the diffusivity. Generally, permeation through membranes is based on the diffusivity and solubility. Therefore, it is deemed that organic fluxes through these hydrophobic membranes are strongly influenced by solubility. We tried to estimate the organic fluxes by Hansen solubility parameter (HSP). HSP, which is based on the cohesion energy per molar volume and is composed of dispersion forces (δd), intermolecular dipole interactions (δp), and hydrogen-bonding interactions (δh), has recently attracted attention as a means for evaluating the resolution and aggregation behavior. Evaluation of solubility for two substances can be represented by using the Ra [(MPa)1/2] value, meaning the distance of HSPs for both of substances. A smaller Ra value means a higher solubility for each substance. On the other hand, it can be estimated that the substances with large Ra value show low solubility. We established the correlation equation, which was based on Ra, of organic flux at low concentrations of organic compounds and at 295-325 K.

Keywords: hydrophobic, membrane, Hansen solubility parameter, functional group

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Authors: Ivna Mororó, Lise P. Labéjof, Stephanie Ribeiro, Kely Almeida

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Lipid droplets (LDs) are normally presented in greater or lesser number in the cytoplasm of almost all eukaryotic and some prokaryotic cells. They are independent organelles composed of a lipid ester core and a surface phospholipid monolayer. As a lipid storage form, they provide an available source of energy for the cell. Recently it was demonstrated that they play an important role in other many cellular processes. Among the many unresolved questions about them, it is not even known how LDs is formed, how lipids are recruited to LDs and how they interact with the other organelles. Excess fat in the organism is pathological and often associated with the development of some genetic, hormonal or behavioral diseases. The formation and accumulation of lipid droplets in the cytoplasm can be increased by exogenous physical or chemical agents. It is well known that ionizing radiation affects lipid metabolism resulting in increased lipogenesis in cells, but the details of this process are unknown. To better understand the mode of formation of LDs in liver cells, we investigate their ultrastructural morphology after irradiation. For that, Wistar rats were exposed to whole body gamma radiation from 60-cobalt at various single doses. Samples of the livers were processed for analysis under a conventional transmission electron microscope. We found that when compared to controls, morphological changes in liver cells were evident at the higher doses of radiation used. It was detected a great number of lipid droplets of different sizes and homogeneous content and some of them merged each other. In some cells, it was observed diffused LDs, not limited by a monolayer of phospholipids. This finding suggests that the phospholipid monolayer of the LDs was disrupted by ionizing radiation exposure that promotes lipid peroxydation of endo membranes. Thus the absence of the phospholipid monolayer may prevent the realization of some cellular activities as follow: - lipid exocytosis which requires the merging of LDs membrane with the plasma membrane; - the interaction of LDs with other membrane-bound organelles such as the endoplasmic reticulum (ER), the golgi and mitochondria and; - lipolysis of lipid esters contained in the LDs which requires the presence of enzymes located in membrane-bound organelles as ER. All these impediments can contribute to lipid accumulation in the cytoplasm and the development of diseases such as liver steatosis, cirrhosis and cancer.

Keywords: radiobiology, hepatocytes, lipid metabolism, transmission electron microscopy

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Authors: Nayera E. Hassan, Sahar A. El-Masry, Mones M. Abu Shady, Rokia A. El Banna, Muhammad Al-Tohamy, Mehrevan M. Abd El-Moniem, Mona Anwar

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Circulating oxidized LDL (ox-LDL) is associated with obesity, insulin resistance (HOMA), metabolic syndrome, and cardiovascular disease in adults. Little is known about relations in children. Aim: To assess association of ox-LDL with fat distribution and insulin resistance in a group of obese Egyptian children. Methods: Study is cross-sectional consisting of 68 obese children, with a mean age of 9.96 ± 1.32. Each underwent a complete physical examination; blood pressure (SBP, DBP) and anthropometric measurements (weight, height, BMI; waist, hip circumferences, waist/hip ratio), biochemical tests of fasting blood glucose (FBS), insulin levels; lipid profile (TC, LDL,HDL, TG) and ox-LDL; calculated HOMA. Sample was classified according to waist/hip ratio into: group I with and group II without central obesity. Results: ox-LDL showed significant positive correlation with LDL and TC in all groups of obesity. After adjustment for age and sex, significant positive correlation was detected between ox-LDL with SBP, DBP, TC, LDL, insulin, and HOMA in group II and with TC and FBS in group I. Insignificant association was detected between ox-LDL and other anthropometric parameters including BMI in any group of obese children (p > 0.05). Conclusions: ox-LDL, as a marker of oxidative stress is not correlated with BMI among all studied obese children (aged 6-12 years). Increased oxidative stress has causal effects on insulin resistance in obese children without central obesity and on fasting blood sugar in those with central obesity. These findings emphasize the importance of obesity during childhood and suggest that the metabolic complications of obesity and body fat distribution are detectable early in life.

Keywords: ox-LDL, obesity, insulin resistance, children

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Authors: Ji-Hoon Byeon, Kwon-Hee Lee

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Strainer filter serves to block the inflow of impurities while mixed fluid is entering or exiting the piping. The filter of the strainer has a perforated structure, so that the pressure drop and the velocity change necessarily occur when the mixed fluid passes through the filter. It is possible to predict the pressure drop and velocity change of the strainer by numerical analysis by implementing all the perforated plates. However, if the size of the perforated plate exceeds a certain size, it is difficult to perform the numerical analysis, and sometimes we cannot guarantee its accuracy. In this study, we tried to predict the pressure drop and velocity change by using the porous media technique to obtain the equivalent resistance without actual implementation of the perforation shape of the strainer. Ansys-CFX, a commercial software, is used to perform the numerical analysis. The analysis procedure is as follows. Firstly, the unit pattern of the perforated plate is modeled, and the pressure drop is analyzed by varying the velocity by symmetry of the wall surface. Secondly, since the equation for obtaining resistance is a quadratic equation of pressure having unknown velocity, the viscous resistance and the inertia resistance of the perforated plate are obtained from the relationship between pressure and speed. Thirdly, by using the calculated resistance values, the values are substituted into the flat plate implemented as a two-dimensional porous media, and the accuracy is verified by comparing the pressure drop and the velocity change. Fourthly, the pressure drop and velocity change in the whole strainer are analyzed by using the resistance values obtained on the perforated plate in the actual whole strainer model. Using the porous media technique, it is found that pressure drop and velocity change can be predicted in relatively short time without modeling the overall shape of the filter. Acknowledgements: This work was supported by the Valve Center from the Regional Innovation Center(RIC) Program of Ministry of Trade, Industry & Energy (MOTIE).

Keywords: strainer, porous media, CFD, numerical analysis

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Authors: Sajjad Rezaei, Mahdieh Molanouri Shamsi, Azadeh Jamali

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Background and purpose: Surfactant protein D (SP-D) is a lung-specific protein that is detectable in human plasma. Effect of exercise training on SP-D levels as well as its relation to metabolic indices is not known. The present study then aimed to investigate the effects of 10 weeks of aerobic training on serum levels of SP-D and insulin resistance in women with type 2 diabetes. Materials and methods: Twenty-two overweight women with type 2 diabetes mellitus were recruited through deliberate sampling and randomly assigned to intervention and control groups (11 in each group). The intervention group underwent a progressive aerobic training program for 10 weeks, 3 days per week, 30-55 min/day at 50-75% heart rate reserve (HRR). Control group continued with its everyday routine. Blood samples were obtained before and after training for biochemical analysis. Within-group and between-group differences were analyzed with paired and independent t-tests in spss software, respectively, and the relation between variables was analyzed with Pearson’s correlation coefficient (all at P = 0.05). Results: Significant differences were observed between groups in leptin, glucose, waist circumference and VO2 max after training. SP-D was decreased and VO2 max was increased significantly in intervention group. However, no significant correlation was observed between SP-D and other variables. Conclusion: Since there was no corresponding decrease in insulin resistance with decreased levels of SP-D, it seems unlikely for SP-D to mediate the association between obesity and insulin resistance in type 2 diabetics.

Keywords: exercise training, SP-D, insulin resistance, type 2 diabetes

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Authors: Fatih Hattatoglu, Abdulrezzak Bakiş

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In this study, fiberless reactive powder concrete (RPC) was produced with high pressure and flexural strength. C30/37 concrete was chosen as the control sample. In this study, 9 different cure types were applied to fiberless RPC. the most suitable combined cure type was selected according to the pressure and flexure strength. Pressure and flexural strength tests were applied to these samples after curing. As a result of the study, the combined cure type with the highest pressure resistance was obtained. The highest pressure resistance was achieved with consecutive standard water cure at 20 °C for 7 days – hot water cure at 90 °C for 2 days - drying oven cure at 180 °C for 2 days. As a result of the study, the highest pressure resistance of fiberless RPC was found as 123 MPa with water cure at 20 °C for 7 days - hot water cure at 90 °C for 2 days - drying oven cure at 180 °C for 2 days; and the highest flexural resistance was found as 8.37 MPa for the same combined cure type.

Keywords: combined cure, flexural test, reactive powder concrete (RPC), rigid pavement, pressure test

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Authors: Naoual Boussoualim, Hayat Trabsa, Iman Krache, Lekhmici Arrar, Abderrahmane Baghiani

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Resistance to antibiotics has emerged following their widespread use; the important mechanism of beta-lactam resistance in bacteria is the production of beta-lactamase. In order to find new bioactive beta-lactamase inhibitors, this study investigated the inhibition effect of the extracts of Anchusa azurea (AA) on a beta-lactamase from Bacillus cereus. The extracts exerted inhibitory effects on beta-lactamase in a dose-dependent manner, the results showed that the crude extract (BrE) and the ethyl acetate extract (AcE) of Anchusa azurea showed a very high inhibitory activity at a concentration of 10 mg, the percentage of inhibition was between 58% and 68%. Not all extracts were as potent as the original inhibitors such as clavulanic acid, the isolation and the structural elucidation of the active constituents in these extracts will provide useful means in the development of beta -lactamase inhibitors.

Keywords: Anchusa azurea, natural product, resistance, antibiotics, beta-lactamase, inhibitors

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Authors: Kebin Li, Keith Morton, Matthew Shiu, Karine Turcotte, Luke Lukic, Teodor Veres

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We present a normally closed thermoplastic microfluidic valve design that uses microstructured valve seats to locally prevent the membrane from bonding to the valve seat during microfluidic channel sealing. The microstructured valve seat reduces the adhesion force between the contact surfaces of the valve seat and the membrane locally, allowing valve open and close operations while simultaneously providing a permanent and robust bond elsewhere to cover and seal the microfluidic channel network. Dynamic valve operation including opening and closing times can be tuned by changing the valve seat diameter as well as the density of the microstructures on the valve seats. The influence of the microstructured valve seat on the general flow behavior through the microfluidic devices was also studied. A design window for the fabrication of valve structure is identified and discussed to minimize the fabrication complexity.

Keywords: hot-embossing, injection molding, microfabrication, microfluidics, microvalves, thermoplastic elastomer

Procedia PDF Downloads 294

Authors: Minoo Tavakoli, Alireza Kiani Rashid, Abbas Afrasiabi

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An aluminum coating deposited on mild steel substrate by electric arc spray and diffused to the base steel material by diffusion treatment at 800 and 900°C for 1 and 3 hours in a static air. Alloy layers formed by diffusion at both temperatures were investigated, and their features were compared with those of pack cementation aluminized steel. High-temperature oxidation tests were carried out in air at 600 °C for 145 hours. Results indicated that the aluminide coatings obtained from this process have significantly improved the high-temperature oxidation resistance in both methods due to the Al2O3 scale formation. Furthermore, it showed that the isothermal oxidation resistance of arc spray technique is better than pack cementation method. This can be attributed to voids that formed at the intermetallic layer /Al layer interface which is increased in the pack cementation method.

Keywords: electric arc spray, pack cementation, oxidation resistance, aluminized steel

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Authors: Seyyed Payman Ziapour, Ahmadali Enayati, Sadegh Kheiri, Farzaneh Sahraei-Rostami, Reza Ali Mohammadpour, Mahmoud Fazeli-Dinan, Mohsen Aarabi, Fatemeh Asgarian, Seyed Hassan Nikookar, Mohammad Sarafrazi

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Rhipicephalus bursa (R. bursa) is a two-host ixodid tick with wide distribution in north of Iran especially in domestic animals of Mazandaran Province. The prolonged or incorrect use of chemical insecticides has led to build up of resistance in hard ticks in many areas of the world. Lack of basic information on resistance status of R. bursa was the reason behind this study to determine the susceptibility status of the species to lambda-cyhalothrin insecticide in Mazandaran Province. From May 2013 to March 2014, R. bursa ticks were collected on sheep, goat and cattle in different districts of Mazandaran Province. The engorged female ticks were reared in a controlled insectary for producing 12-18 days old larvae for larval packet test (LPT) bioassay against discriminant doses of lambda-cyhalothrin 5% EC (MAC SILAT®). 80% of ten pooled tick populations were susceptible to lambda-cyhalothrin as resistance ratios (RR50s) varied from 1 to 2.94 when compared with the most susceptible population NH-16. Only GK-12 and BF-6 populations (from plain areas of Galugah and Fereydunkenar Counties, respectively) were classified as resistant level I at LC50 level. Population NK-2 (from woodland areas of Kojour district in Nowshahr County) showed the highest resistance ratio of RR99 = 4.32 and 30% of tick populations were resistant at LC99 level. Our research showed initiation of lambda-cyhalothrin resistance in Rhipicephalus bursa populations in Mazandaran Province, Northern Iran. This is considered a warning to policy makers for disease control in the study area. This research is a part of the PhD thesis of SP. Ziapour by grant No. 92-89 in Student Research Committee, Mazandaran University of Medical Sciences, Iran.

Keywords: Rhipicephalus bursa, hard tick, lambda-cyhalothrin resistance, Iran

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Authors: Alex J. Summers, Jasmine P. Devadhasan, Douglas Montgomery, Brittany Fischer, Jian Gu, Frederic Zenhausern

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Immunoassays have been utilized for several applications, including the detection of pathogens. Our laboratory is in the development of a tier 1 biothreat panel utilizing Vertical Flow Assay (VFA) technology for simultaneous detection of pathogens and toxins. One method of manufacturing VFA membranes is with non-contact piezoelectric dispensing, which provides advantages, such as low-volume and rapid dispensing without compromising the structural integrity of antibody or substrate. Challenges of this processinclude premature discontinuation of dispensing and misaligned spotting. Preliminary data revealed the Yp 11C7 mAb (11C7)reagent to exhibit a large angle of failure during printing which may have contributed to variable printing outputs. A Design of Experiment (DOE) was executed using this reagent to investigate the effects of hydrostatic pressure and reagent concentration on microarray printing outputs. A Nano-plotter 2.1 (GeSIM, Germany) was used for printing antibody reagents ontonitrocellulose membrane sheets in a clean room environment. A spotting plan was executed using Spot-Front-End software to dispense volumes of 11C7 reagent (20-50 droplets; 1.5-5 mg/mL) in a 6-test spot array at 50 target membrane locations. Hydrostatic pressure was controlled by raising the Pressure Compensation Vessel (PCV) above or lowering it below our current working level. It was hypothesized that raising or lowering the PCV 6 inches would be sufficient to cause either liquid accumulation at the tip or discontinue droplet formation. After aspirating 11C7 reagent, we tested this hypothesis under stroboscope.75% of the effective raised PCV height and of our hypothesized lowered PCV height were used. Humidity (55%) was maintained using an Airwin BO-CT1 humidifier. The number and quality of membranes was assessed after staining printed membranes with dye. The droplet angle of failure was recorded before and after printing to determine a “stroboscope score” for each run. The DOE set was analyzed using JMP software. Hydrostatic pressure and reagent concentration had a significant effect on the number of membranes output. As hydrostatic pressure was increased by raising the PCV 3.75 inches or decreased by lowering the PCV -4.5 inches, membrane output decreased. However, with the hydrostatic pressure closest to equilibrium, our current working level, membrane output, reached the 50-membrane target. As the reagent concentration increased from 1.5 to 5 mg/mL, the membrane output also increased. Reagent concentration likely effected the number of membrane output due to the associated dispensing volume needed to saturate the membranes. However, only hydrostatic pressure had a significant effect on stroboscope score, which could be due to discontinuation of dispensing, and thus the stroboscope check could not find a droplet to record. Our JMP predictive model had a high degree of agreement with our observed results. The JMP model predicted that dispensing the highest concentration of 11C7 at our current PCV working level would yield the highest number of quality membranes, which correlated with our results. Acknowledgements: This work was supported by the Chemical Biological Technologies Directorate (Contract # HDTRA1-16-C-0026) and the Advanced Technology International (Contract # MCDC-18-04-09-002) from the Department of Defense Chemical and Biological Defense program through the Defense Threat Reduction Agency (DTRA).

Keywords: immunoassay, microarray, design of experiment, piezoelectric dispensing

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Authors: Juan Carlos Baena, Zhongxiao Peng

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Ultra-high molecular weight polyethylene (UHMWPE) is extensively used in industrial and biomedical fields. The slippery nature of UHMWPE makes this material suitable for surface bearing applications, however, the operational conditions limit the lubrication efficiency, inducing boundary and mixed lubrication in the tribological system. The lack of lubrication in a tribological system intensifies friction, contact stress and consequently, operating temperature. With temperature increase, the material’s mechanical properties are affected, and the lifespan of the component is reduced. The understanding of how mechanical properties and wear performance of UHMWPE change when the temperature is increased has not been clearly identified. The understanding of the wear and mechanical performance of UHMWPE at different temperature is important to predict and further improve the lifespan of these components. This study evaluates the effects of temperature variation in a range of 20 °C to 60 °C on the hardness and the wear resistance of UHMWPE. A reduction of the hardness and wear resistance was observed with the increase in temperature. The variation of the wear rate increased 94.8% when the temperature changed from 20 °C to 50 °C. Although hardness is regarded to be an indicator of the material wear resistance, this study found that wear resistance decreased more rapidly than hardness with the temperature increase, evidencing a low material stability of this component in a short temperature interval. The reduction of the hardness was reflected by the plastic deformation and abrasion intensity, resulting in a significant wear rate increase.

Keywords: hardness, surface bearing, tribological system, UHMWPE, wear

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Authors: Sara Boulmai̇z

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In order to study the microbiological quality of chawarma sold in Biskra, a sampling through some fastfoods of the city was done, the parameters studied are highlighted according to the criteria required by the country's trade management. Microbiological analyzes revealed different levels of contamination by microorganisms. The 10 samples were of an overall view of unsatisfactory quality, and according to the standards, no sample was satisfactory. The range of total aerobic mesophilic flora found is between 105 and 1.2 × 10 7 CFU / g, that of fecal coliforms is 104 to 2.4 × 10 5 CFU / g. The suspected pathogenic staphylococci were between 3.103 and 2.7.106 CFU / g. Salmonellae were absent in all samples, whereas sulphite-reducing anaerobes were present in a single sample. The rate of E. cloacae was between 103 and 6.104 CFU / g. As for fungi and safe mice, their rate was 103 to 107 CFU / g. The study of the sensitivity of antibiotics showed multi-resistance to all the antibiotics tested, although there is a sensitivity towards others. All strains of Staphylococcus aureus tested demonstrated resistance against erythromycin, 30% against streptomycin, and 10% against tetracycline. While the strains of E. cloacae were resistant in all strains to amoxicillin, ceftazidime, cefotaxime, and erythromycin, while they were sensitive to fosfomycin, sulfamethoxazole trimethoperine, ciprofloxacin, and tetracycline. While against chlorophenicol and ofloxacin, the sensitivity was dominant, although there was intermediate resistance. In this study demonstrates that foodborne illnesses remain a problem that arises in addition to the increasingly observed bacterial resistance and that, after all, healthy eating is a right.

Keywords: chawarma, microbiological quality, pathogens., street food

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Authors: Ko-Shao Chen, Yun Tsao, Chia-Hsuan Tsen, Chien-Chung Chen, Shu-Chuan Liao

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Electrospun microtube array membranes (MTAMs) made of PLLA (poly-L-lactic acid) have wide potential applications in tissue engineering. However, their surface hydrophobicity and poor biocompatability have limited their further usage. In this study, the surface of PLLA MTAMs were made hydrophilic by introducing extra functional groups, such as peroxide, via an acetic acid plasma (AAP). UV-graft polymerization of acrylic acid (G-AAc) was then used to produce carboxyl group on MTAMs surface, which bonded covalently with chitosan through EDC / NHS crosslinking agents. To evaluate the effects of the surface modification on PLLA MTAMs, water contact angle (WCA) measurement and cell compatibility tests were carried out. We found that AAP treated electrospun PLLA MTAMs grafted with AAc and, finally, with chitosan immobilized via crosslinking agent, exhibited improved hydrophilic and cell compatibility.

Keywords: plasma, EDC/NHS, UV grafting, Chitosan, microtube array membrane (MTAMs)

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