Search results for: localized surface plasmon resonance effect

Authors: Noreen Sajjad Ghulam Hussain

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Catalysts are prepared by simple physical mixing and thermal treatment of support and metal acetate precursors.The effect of metal ratio and metal loading to produce highly active catalyst for the oxidation of benzyl alcohol are studied.

Keywords: catalyst, acetates, benzyl alcohols

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Authors: Boonyarat Chaleephay

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The purpose of this research paper was to describe the relationship of acupressure points on the anterior surface of the upper limb in accordance with Applied Thai Traditional Massage (ATTM) and the deep structures located at those acupressure points. There were 2 population groups; normal subjects and cadaver specimens. Eighteen males with age ranging from 20-40 years old and seventeen females with ages ranging from 30-97 years old were studies. This study was able to obtain a fundamental knowledge concerning acupressure point and the deep structures that related to those acupressure points. It might be used as the basic knowledge for clinically applying and planning treatment as well as teaching in ATTM.

Keywords: acupressure point (AP), applie Thai traditional medicine (ATTM), paresthesia, numbness

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Authors: Saifon Chongthub

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The purpose of this research is to synthesize adsorbent foam for CO2 adsorption. The polymer was prepared from poly High Internal Phase Emulsion (PolyHIPE) using styrene as monomer and divinylbenzene as comonomer. Its morphology was determined by Scanning Electron Microscopy (SEM). To further increased CO2 adsorption of the prepared polyHIPE, the layer by layer (LbL) technique was applied, which alternated polyelectrolyte injection between layers of Poly(styrenesulfonate) (PSS) and Poly(diallyldimetyl-ammonium chloride)(PDADMAC) as primary layer, and layers of PSS and polyetyleneimine (PEI) as secondary layer.

Keywords: high internal phase emulsion, polyHIPE, surface modification, layer by layer technique, CO2 adsorption

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Authors: Iyad M. Muslih, Yehya Abdellatif, Sara Qutishat

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Renewable energy and in particular solar photovoltaic energy is emerging as a reasonable power generation source. The intermittent and unpredictable nature of solar energy can represent a serious challenge to the utility grids, specifically at relatively high penetration. To minimize the impact of PV power systems on the grid, self-consumption is encouraged. Self-consumption can be improved by matching the PV power generation with the electrical load consumption profile. This study will focus in studying different load profiles and comparing them to typical solar PV power generation at the selected sites with the purpose of analyzing the mismatch in consumption load profile for different users; residential, commercial, and industrial versus the solar photovoltaic output generation. The PV array orientation can be adjusted to reduce the mismatch effects. The orientation shift produces a corresponding shift in the energy production curve. This shift has a little effect on the mismatch for residential loads due to the fact the peak load occurs at night due to lighting loads. This minor gain does not justify the power production loss associated with the orientation shift. The orientation shift for both commercial and industrial cases lead to valuable decrease in the mismatch effects. Such a design is worth considering for reducing grid penetration. Furthermore, the proposed orientation shift yielded better results during the summer time due to the extended daylight hours.

Keywords: grid impact, HOMER, power mismatch, solar PV energy

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Authors: David Guillermo Piedrahita Marquez, Hector Suarez Mahecha, Jairo Humberto Lopez

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It was necessary to establish which formulation is suitable for the preservation of aquaculture products, that why edible films were made. These were to a characterization in order to meet their morphology physicochemical and mechanical properties, optical. Six Formulations of chitosan and propolis ethanolic extract encapsulated were developed because of their activity against pathogens and due to their properties, which allows the creation waterproof polymer networks against gasses, vapor, and physical damage. In the six Formulations, the concentration of comparison material (1% w/v, 2% pv) and the bioactive concentrations (0.5% w/v, 1% w/v, 1.5% pv) were changed and the results obtained were compared with statistical and multivariate analysis methods. It was observed that the matrices showed a mayor impermeability and thickness control samples and the samples reported in the literature. Also, these films showed a notorious uniformity of the films and a bigger resistance to the physical damage compared with other edible films made of other biopolymers. However the action of some compounds had a negative effect on the mechanical properties and changed drastically the optical properties, the bioactive has an effect on Polymer Matrix and it was determined that the films with 2% w / v of chitosan and 1.5% w/v encapsulated, exhibited the best properties and suffered to a lesser extent the negative impact of immiscible substances.

Keywords: chitosan, edible films, ethanolic extract of propolis, mechanical properties, optical properties, physical characterization, scanning electron microscopy (SEM)

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Authors: Rara Wulan Anggareni, Narita Putri, Riski Septianing Astuti

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Breastfeeding is a key to prevent mortality and morbidity in children. It is also the second highest risk responsible for Disability Adjusted Life Years (DALYs) among children below five years old. UNICEF estimates that during 1995 – 2003, there are only about 38% infants in developing countries who get to be exclusively breastfed during the first six months of their lives. According to Demography and Health Survey in Indonesia 2007, breastfeed practice rate still considered as low which is about 41%. One of the factors causing the low breastfeed practice rate in Indonesia is the anxiety and postpartum depression, and also the weanling dilemma in which mother feels that her breastmilk cannot suffice infant needs. Those factors finally resulting into low or even stopped production of breastmilk. Breastmilk production can be enhanced by consuming food containing phytosterol and lactogoga effect. Food with the highest phytosterol level is Sauropus androgynus (L.) Merr leaf (merr leaf). In this study, we made alternative food which named Chocomerr for breastfeeding mothers. Chocomerr consists of merr leaves which have lactogoga effect and chocolate for relaxation. Based on organoleptic tests conducted towards 2 age groups, which are 18 – 21 and 25 – 40 years old, this product gets good acceptance in taste, texture, and colour categories. Chocomerr can be used as an alternative way for increasing breastmilk production to aim for the decreasing number of DALYs among children aged under 5 years old.

Keywords: breastfeeding, increasing, chocolate, merr leaves

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Authors: Che Jusoh, Mohd Rahimi, Toby Mundel

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This study was designed to investigate the physiological and performance effects of a local Malaysian native starch (Metroxylin sago) on cycling in a hot (30°C) and humid (78% RH) environment. Eight male, non-heat acclimated, well-trained club cyclists (VO2max 65 ± 10 ml kg-1 min-1, peak aerobic power 397 ± 71 W) completed one familiarization and three experimental trials in our laboratory simulating cycling in environmental conditions of heat and humidity. Each trial consisted of 45 minutes at a fixed workload (55% VO2max) followed by a 15 minute time-trial (~75% VO2max). Sago in porridge form was consumed 1h before exercise (Pre), in gel form during exercise (Dur) and compared to a control trial (Con), using a random, cross-over design. Plasma glucose concentration did not differ between trials (P = 0.06) with an increase from 4.1 ± 0.6 to 6.1 ± 1.6 mmol-1 (Con), 4.8 ± 1.7 to 5.7 ± 0.4 mmol-1 (Pre) and 4.7 ± 0.8 to 6.9 ± 1.4 mmol-1 (Dur) from start to end of exercise. Plasma lactate increased (P = 0.02) from 1.6 ± 0.3 to 7.6 ± 2.2 mmol-1 (Con), 1.7 ± 0.5 to 7.3 ± 2.9 mmol-1 (Pre) and 1.6 ± 0.2 to 7.3 ± 1.8 mmol-1 (Dur) with no effect of trial (P = 0.74). No differences were found between trials for RER (P = 0.328) with values of 0.93 ± 0.05 (Con), 0.94 ± 0.04 (Pre) and 0.92 ± 0.04 (Dur). There were no differences between trials in rectal (P = 0.64) and skin (P = 0.56) temperatures; values reaching 39.1 ± 0.5°C (Con), 38.9 ± 0.4°C (Pre) and 39.1 ± 0.4°C (Dur) for rectal and 32.7 ± 1.2°C (Con), 32.8 ± 1.4°C (Pre) and 32.8 ± 1.8°C (Dur) for skin temperature, respectively. Heart rate (P = 0.07) also did not differ between trials but reached maximal values by the end of time-trial for all trials. Performance was unaffected by trial (P = 0.98) with the average work completed in 15 minutes being 221 ± 33 kJ (Con), 222 ± 31 kJ (Pre) and 219 ± 32 kJ (Dur), respectively. Therefore, the results of this investigation do not support consumption of sago, either before or during exercise, in altering the thermoregulatory, metabolic or performance responses in a hot and humid environment.

Keywords: hot and humid, physiology, time trial performance, thermoregulatory

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Authors: Ying Weiyong

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The micro/mesoporous core-shell composites compromising SSZ-13 cores and mesoporous silica shells were synthesized successfully with the soft template of cetytrimethylammonium. The shell thickness could be tuned from 25 nm to 100 nm by varying the TEOS/SSZ-13 ratio. The BET and SEM results show the core-shell composites possessing the tunable surface area (544.7-811.0 m2/g) with plenty of mesopores (2.7 nm). The acidity intensity of the strong acid sites on SSZ-13 was remarkably impaired with the decoration of the mesoporous silica shell, which leads to the suppression of the hydrogen transfer reaction in MTO reaction. The micro/mesoporous core-shell composites exhibit better methanol to olefins reaction performance with a prolonged lifetime and the improvement of light olefins selectivity.

Keywords: core-shell, mesoporous silica, methanol to olefins, SSZ-13

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Authors: M. Javanmard

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This study was aimed at analyzing the effects of packaging (MAP) and preservation conditions on the packaged fresh walnut kernel quality. The central composite plan was used for evaluating the effect of oxygen (0–10%), carbon dioxide (0-10%), and temperature (4-26 °C) on qualitative characteristics of walnut kernels. Also, the response level technique was used to find the optimal conditions for interactive effects of factors, as well as estimating the best conditions of process using least amount of testing. Measured qualitative parameters were: peroxide index, color, decreased weight, mould and yeast counting test, and sensory evaluation. The results showed that the defined model for peroxide index, color, weight loss, and sensory evaluation is significant (p < 0.001), so that increase of temperature causes the peroxide value, color variation, and weight loss to increase and it reduces the overall acceptability of walnut kernels. An increase in oxygen percentage caused the color variation level and peroxide value to increase and resulted in lower overall acceptability of the walnuts. An increase in CO₂ percentage caused the peroxide value to decrease, but did not significantly affect other indices (p ≥ 0.05). Mould and yeast were not found in any samples. Optimal packaging conditions to achieve maximum quality of walnuts include: 1.46% oxygen, 10% carbon dioxide, and temperature of 4 °C.

Keywords: shelled walnut, MAP, quality, storage temperature

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Authors: Rayed Alyousef, Tim Topper, Adil Al-Mayah

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This paper presents results of an ongoing research program at University of Waterloo to study the effect of external FRP sheet wrap confinement along a lap splice of reinforced concrete (RC) beams on their fatigue bond strength. Fatigue loading of RC beams containing a lap splice resulted in an increase in the number and width of cracks, an increase in deflection and a decrease of the bond strength between the steel rebar and the surrounding concrete. The phase of the research described here consists of monotonic and fatigue tests of thirty two reinforced concrete beam with dimensions 2200⨉350⨉250 mm. Each beam was reinforced with two 20M bars lap spliced in the constant moment region of the tension zone and two 10M bars in the compression zone outside the constant moment region. The test variables were the presence or absence of a FRP wrapping, the type of the FRP wrapping (GFRP or CFRP), the type of loading and the fatigue load range. The test results for monotonic loading showed that the stiffness of all beams was almost same, but that the FRP sheet wrapping increased the bond strength and the deflection at ultimate load. All beams tested under fatigue loading failed by a bond failure except one CFRP wrapped beam that failed by fatigue of the main reinforcement. The FRP sheet increased the bond strength for all specimens under fatigue loading.

Keywords: lap splice, bond strength, fatigue loading, FRP

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Authors: Danielle Slomberg, Jerome Labille, Riccardo Catalano, Jean-Claude Hubaud, Alexandra Lopes, Alice Tagliati, Teresa Fernandes

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In the assessment and management of cosmetics and personal care products, sunscreens are of emerging concern regarding both human and environmental health. Organic UV blockers in many sunscreens have been evidenced to undergo rapid photodegradation, induce dermal allergic reactions due to skin penetration, and to cause adverse effects on marine systems. While mineral UV-blockers may offer a safer alternative, their fate and impact and resulting regulation are still under consideration, largely related to the potential influence of nanotechnology-based products on both consumers and the environment. Nanometric titanium dioxide (TiO₂) UV-blockers have many advantages in terms of sun protection and asthetics (i.e., transparency). These UV-blockers typically consist of rutile nanoparticles coated with a primary mineral layer (silica or alumina) aimed at blocking the nanomaterial photoactivity and can include a secondary organic coating (e.g., stearic acid, methicone) aimed at favouring dispersion of the nanomaterial in the sunscreen formulation. The nanomaterials contained in the sunscreen can leave the skin either through a bathing of everyday usage, with subsequent release into rivers, lakes, seashores, and/or sewage treatment plants. The nanomaterial behaviour, fate and impact in these different systems is largely determined by its surface properties, (e.g. the nanomaterial coating type) and lifetime. The present work aims to develop the eco-design of sunscreens through the minimisation of risks associated with nanomaterials incorporated into the formulation. All stages of the sunscreen’s life cycle must be considered in this aspect, from its manufacture to its end-of-life, through its use by the consumer to its impact on the exposed environment. Reducing the potential release and/or toxicity of the nanomaterial from the sunscreen is a decisive criterion for its eco-design. TiO₂ UV-blockers of varied size and surface coating (e.g., stearic acid and silica) have been selected for this study. Hydrophobic TiO₂ UV-blockers (i.e., stearic acid-coated) were incorporated into a typical water-in-oil (w/o) formulation while hydrophilic, silica-coated TiO₂ UV-blockers were dispersed into an oil-in-water (o/w) formulation. The resulting sunscreens were characterised in terms of nanomaterial localisation, sun protection factor, and photo-passivation. The risk to the direct aquatic environment was assessed by evaluating the release of nanomaterials from the sunscreen through a simulated laboratory aging procedure. The size distribution, surface charge, and degradation state of the nano-composite by-products, as well as their nanomaterial concentration and colloidal behaviour were determined in a variety of aqueous environments (e.g., seawater and freshwater). Release of the hydrophobic nanocomposites into the aqueous environment was driven by oil droplet formation while hydrophilic nano-composites were readily dispersed. Ecotoxicity of the sunscreen by-products (from both w/o and o/w formulations) and their risk to marine organisms were assessed using coral symbiotes and tropical corals, evaluating both lethal and sublethal toxicities. The data dissemination and provided risk knowledge from the present work will help guide regulation related to nanomaterials in sunscreen, provide better information for consumers, and allow for easier decision-making for manufacturers.

Keywords: alteration, environmental fate, sunscreens, titanium dioxide nanoparticles

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Authors: Bhavya Tripathi, Bhupendra Kumar Sharma

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In blood, the concentration of red blood cell varies with the arterial diameter. In the case of narrow arteries, red blood cells concentrate around the center of the artery and there exists a cell-free plasma layer near the arterial wall due to Fahraeus-Lindqvist effect. Due to non- uniformity of the fluid in the narrow arteries, it is preferable to consider the two-phase model of the blood flow. In the present article, coupled nonlinear differential equations have been developed for momentum, energy and concentration of two phase model of the blood flow assuming the Newtonian fluid in both central core and cell free plasma layer and the exact solutions have been found for the problem. For having an adequate insight into the stenosed arterial two-phase blood flow, major components of the flow as flow resistance, total flow rate, and wall shear stress have been estimated for different values of magnetic and radiation parameter. Results show that the increase in the effects of magnetic field decreases the velocity of both cores as well as plasma regions. This result can be helpful to control the blood flow in narrow arteries during surgical process. Temperature of core as well plasma regions decrease as value of radiation parameter increases. The present result is implemented in the form of radiation therapy which is very helpful for cancer patients.

Keywords: two phase blood flow, radiation, magnetohydrodynamics (MHD), stenosis

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Authors: Azita Behbahaninia

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This research has been carried out to determine the water quality and physico-chemical properties Polour River, one of the most branch of Haraz River. Polour River was studied for a period of one year Samples were taken from different stations along the main branch of River polour. In water samples determined pH, DO, SO4, Cl, PO4, NO3, EC, BOD, COD, Temprature, color and number of Caliform per liter. ArcGIS was used for the zoning of phosphate concentration in the polour River basin. The results indicated that the river is polluted in polour village station, because of discharge domestic wastewater and also river is polluted in Ziar village station, because of agricultural wastewater and water is contaminated in aquaculture station, because of fish ponds wastewater. Statistical analysis shows that between independent traits and coliform regression relationship is significant at the 1% level. Coefficient explanation index indicated independent traits control 80% coliform and 20 % is for unknown parameters. The causality analysis showed Temperature (0.6) has the most positive and direct effect on coliform and sulfate has direct and negative effect on coliform. The results of causality analysis and the results of the regression analysis are matched and other forms direct and indirect effects were negligible and ignorable. Kruskal-Wallis test showed, there is different between sampling stations and studied characters. Between stations for temperature, DO, COD, EC, sulfate and coliform is at 1 % and for phosphate 5 % level of significance.

Keywords: coliform, GIS, pollution, phosphate, river

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Authors: M. Unaldi, R. Kus

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Brake pads are important parts of the braking system and they are made of different materials. Use of asbestos fibre can cause health risks. The goal of this study is to determine the effect of ecological brake pad samples which are produced under different compaction pressure values and mixture ratios by using miscanthus as reinforcement component on the density, hardness, wear rate and compression strength properties, and friction coefficients changes of ecological brake pad samples. Miscanthus powder, cashew powder, alumina powder, phenolic resin powder, and calcite powder mixtures were used to produce ecological brake pad samples. The physical properties of the brake pad samples produced under different mixture ratios and compaction pressures values were determined to assign their effects on them by using Taguchi experimental design. Mixture ratios and compaction pressures values were chosen as the factors with three-levels. Experiments are conducted to L₉(3⁴) Taguchi orthogonal array design. The results showed that hardness value is very much affected both compaction pressure values and mixture ratios than the other physical properties. When reinforcing component ratio within the mixture and compaction pressure value is increased, hardness and compression strength values of the all samples are also increased. All test results taking into account, the ideal compaction value for used components and mixture ratios were determined as 200 MPa.

Keywords: brake pad, eco-friendly materials, hardness, Miscanthus, Taguchi method

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Authors: P. Efstathiou, E. Kouskouni, S. Papanikolaou, K. Karageorgou, Z. Manolidou, Tseroni Maria, A. Efstathiou, V. Karyoti, I. Agrafa

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Aim: Aim of this study was to evaluate the reduction on Intensive Care Unit (ICU) microbial flora after the antimicrobial copper alloy (Cu+) implementation as well as the effect on financial-epidemiological operation parameters. Methods: Medical, epidemiological and financial data in two time periods, before and after the implementation of copper (Cu 63% - Zn 37%, low lead) were recorded and analyzed in a general ICU. The evaluated parameters were: the importance of patients' admission (Acute Physiology and Chronic Health Evaluation - APACHE II and Simplified Acute Physiology Score - SAPS), microbial flora's record in the ICU before and after the implementation of Cu+ as well as the impact on epidemiological and ICU's operation financial parameters. Results: During December 2010 and March 2011 and respectively during December 2011 and March 2012 comparative results showed statistically significant reduction on the microbial flora (CFU/ml) by 95% and the use of antimicrobial medicine (per day per patient) by 30% (p = 0,014) as well as patients hospitalization time and cost. Conclusions: The innovative implementation of antimicrobial copper in ICUs contributed to their microbial flora significant reduction and antimicrobial drugs use reduction with the apparent positive effect (decrease) in both patient’s hospitalization time and cost. Under the present circumstances of economic crisis, survey results are of highest importance and value.

Keywords: antimicrobial copper, financial benefits, ICU, cost reduction

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Authors: Anamika Choudhary, Neha Qurrat Ain

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Background: Congenital agenesis of uterine cervix is a rare anomaly often associated with partial or complete agenesis of vagina. Here is a case report of a 14 year old girl who presented with primary amenorrhea and cyclical abdominal pain since last one year with suprapubic mass palpable. On examination complete absence of a vagina was found, and ultrasound along with magnetic resonance imaging (MRI) suggested cervicovaginal agenesis associated with cryptomenorrhea, which resulted in hematometra and b/l hematosalpinx with pelvic endometriosis. After proper counseling regarding anastomosis failure and the need for future laprotomy or hysterectomy, the patient planned for laparoscopic uterovaginal anastomosis with modified McIndoe vaginoplasty with split skin graft. Case Summary: Chief complaint: The 14 year old girl presented with primary amenorrhea and cyclical abdominal pain. Diagnosis:On history, examination and investigations we made differential diagnoses of cervicovaginal agenesis, cervicovaginal atresia. Post operatively, we concluded it’s a cervicovaginal agenesis. Intervention: Laparoscopic uterovaginal anastomosis was done, and neovagina was created using split skin graft from the thigh and silicone stent. The graft was kept patent, and restenosis was prevented using a dental mould as vaginal dilator. Outcome: Postoperatively 1 year follow-up has been done. We have observed successful uterovaginal anastomosis and good uptake of graft. We also observed the resumption of normal menstrual bleeding. Currently, there has been no restenosis, abnormal vaginal discharge and decreased dysmenorrhea. Conclusion: Laparoscopic-assisted uterovaginal anastomosis can be the treatment of choice in patients with cervical agenesis and atresia instead of hysterectomy, thereby preserving the reproductive function. This conservative approach has better outcomes, as stated in the procedure below. The procedure is successful insofar as the resumption of menstrual function. However, long-term reproductive outcomes, progression of endometriosis, functioning of fallopian tubes, and sexual life in these girls will require further follow-up.

Keywords: cervicovaginal agenesis, uterovaginal anastomosis, dental mould, silicon stent

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Authors: Thoetchai Peeraphatdit, Peter A. Brady, Suraj Kapa, Samuel J. Asirvatham, Niyada Naksuk

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Background: Serum electrolyte abnormalities are a common cause of an acquired prolonged QT syndrome, especially, in the coronary care unit (CCU) setting. Optimal electrolyte ranges among the CCU patients have not been sufficiently investigated. Methods: We identified 8,498 consecutive CCU patients who were admitted to the CCU at Mayo Clinic, Rochester, the USA, from 2004 through 2013. Association between first serum electrolytes and baseline corrected QT intervals (QTc), as well as in-hospital mortality, was tested using multivariate linear regression and logistic regression, respectively. Serum potassium 4.0- < 4.5 mEq/L, ionized calcium (iCa) 4.6-4.8 mg/dL, and magnesium 2.0- < 2.2 mg/dL were used as the reference levels. Results: There was a modest level-dependent relationship between hypokalemia ( < 4.0 mEq/L), hypocalcemia ( < 4.4 mg/dL), and a prolonged QTc interval; serum magnesium did not affect the QTc interval. Association between the serum electrolytes and in-hospital mortality included a U-shaped relationship for serum potassium (adjusted odds ratio (OR) 1.53 and OR 1.91for serum potassium 4.5- < 5.0 and ≥ 5.0 mEq/L, respectively) and an inverted J-shaped relationship for iCa (adjusted OR 2.79 and OR 2.03 for calcium < 4.4 and 4.4- < 4.6 mg/dL, respectively). For serum magnesium, the mortality was greater only among patients with levels ≥ 2.4 mg/dL (adjusted OR 1.40), compared to the reference level. Findings were similar in sensitivity analyses examining the association between mean serum electrolytes and mean QTc intervals, as well as in-hospital mortality. Conclusions: Serum potassium 4.0- < 4.5 mEq/L, iCa ≥ 4.6 mg/dL, and magnesium < 2.4 mg/dL had a neutral effect on QTc intervals and were associated with the lowest in-hospital mortality among the CCU patients.

Keywords: calcium, electrocardiography, long-QT syndrome, magnesium, mortality, potassium

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Authors: Mahendrasingh J. Pawar, M. D. Gaoner

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Ta-doped Nb2O5 (Ta content 0.5-2% mole fraction) nanoparticles in the range of 20-40 nm were synthesized by combustion technique. The crystalline phase, morphology and size of the nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-vis spectroscopy. The specific surface area of the nanoparticles was measured by nitrogen adsorption (BET analysis). The undoped Nb2O5 nanoparticles were found to have the particles size in the range of 50−80 nm. The photocatalytic performance of the samples was characterized by degrading 20 mg/L toluene under UV−Vis irradiation. The results show that the Ta-doped Nb2O5 nanoparticles exhibit a significant increase in photocatalytic performance over the undoped Nb2O5 nanoparticles, and the Nb2O5 nanoparticles doped with 1.5% Ta and calcined at 450°C show the best photocatalytic performance.

Keywords: Nb2O5, Ta-doped Nb2O5, photodegradation of Toluene, combustion method

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Authors: Tawfiq Chekifi, Brahim Dennai, Rachid Khelfaoui

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Over the last few decades, modeling immiscible fluids such as oil and water have been a classical research topic. Droplet-based microfluidics presents a unique platform for mixing, reaction, separation, dispersion of drops, and numerous other functions. For this purpose, several devices were studied, as well as microfluidic oscillator. The latter was obtained from wall attachment microfluidic amplifiers using a feedback loop from the outputs to the control inputs, nevertheless this device have not well used for microdrops applications. In this paper, we suggest a numerical CFD study of a microfluidic oscillator with two different lengths of feedback loop. In order to produce simultaneous microdrops of gasoil on water, a typical geometry that includes double T-junction is connected to the fluidic oscillator. The generation of microdrops is computed by volume-of-fluid method (VOF). Flow oscillations of microdrops were triggered by the Coanda effect of jet flow. The aim of work is to obtain a high oscillation frequency in output of this passive device, the influence of hydrodynamics and physics parameters on the microdrops frequency in the output of our microsystem is also analyzed, The computational results show that, the length of feedback loop, applied pressure on T-junction and interfacial tension have a significant effect on the dispersion of microdrops and its oscillation frequency. Across the range of low Reynold number, the microdrops generation and its dynamics have been accurately controlled by adjusting applying pressure ratio of two phases.

Keywords: fluidic oscillator, microdrops manipulation, VOF (volume of fluid method), microfluidic oscillator

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Authors: H. Al-Hajeri

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The computation of the effectiveness of turbulence enhancement surface features, such as ribs as means of promoting mixing and hence heat transfer, has attracted the continued attention of the engineering community. In this study, the simulation of a three-dimensional cooling passage is carried out employing a number of turbulence models including Durbin model. The cooling passage consists of a square section duct whose upper and lower surfaces feature staggered cuboid ribs. The main objective of this paper is to provide comparisons of the performance of the v2-f model against other established turbulence models as implemented in the commercial CFD code Ansys Fluent. The present study demonstrates that the v2-f model can successfully capture the isothermal air flow phenomena in flow over obstacles.

Keywords: CFD, cooling passage, Durbin model, turbulence model

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Authors: Sujayeva V. A., Karpova I. S., Koslataya O. V., Kolyadko M. G., Russkikh I. I., Vankovich E. A.

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Objective: The goal of this study is to develop a method for the prevention of the progression of heart failure (HF) in patients with post-infarction cardiosclerosis who have suffered coronavirus infection. Methods: 135 patients with post-infarction cardiosclerosis were divided into 2 groups: Group I - patients who had suffered COVID-19 - 85 people, and Group II - patients who had not suffered COVID-19 - 50 people. Patients of group I, depending on the level of N-terminal fragment of natriuretic peptide (NTproBNP), were divided into 2 subgroups - subgroup A - with HF - 40 people, subgroup B - without HF - 45 people. All patients underwent a clinical examination, echocardiography, electrocardiotopography in 60 leads, computed angiography of the coronary arteries, heart magnetic resonance imaging, NTproBNP. Results: In the post-Covid period, in patients with post-infarction cardiosclerosis, remodeling of the left ventricle and right parts of the heart, deterioration of the systolic-diastolic function of both ventricles, increased pressure in the pulmonary artery, progression of coronary artery atherosclerosis, and an increase in the size of myocardial fibrosis were revealed. The consequence of these changes was the progression of heart failure. The developed method of medical prevention made it possible to improve the clinical course of coronary artery disease and prevent the progression of chronic heart failure in patients with post-infarction cardiosclerosis. Conclusions: In patients with post-infarction cardiosclerosis who initially had HF, after 1 year, according to laboratory and instrumental data, a slight decrease in its severity was revealed. In patients with post-infarction cardiosclerosis who did not have HF before COVID-19, HF developed 1 year after the coronavirus disease, which may be due to the identified process of myocardial fibrosis, which dictates the need to prevent the development of HF in patients with post-infarction cardiosclerosis, even those who did not initially have HF. The proposed method of medical prevention made it possible to improve the clinical course of coronary artery disease in patients with post-infarction cardiosclerosis after COVID-19, both in persons with and without HF, when included in the study. A method of medical prevention in people with post-infarction cardiosclerosis after COVID-19 infection, including spironolactone, loop diuretics, empagliflozin, sacubitril/valsartan, helped prevent the progression of HF.

Keywords: elderly, myocardial infarction, COVID-19, prevention

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Authors: Seyed Mehdi Hashemi, Gholamreza Raisali, Mehran Taheri

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One of the important problems of using high energy linacs at IMRT is the production of photoneutrons. Besides the clinically useful photon beams, high-energy photon beams from medical linacs produce secondary neutrons. These photoneutrons increase the patient dose and may cause secondary malignancies. The effect of the shield on the reduction of photoneutron dose equivalent produced by a high energy medical linac at the patient plane is investigated in this study. To determine the photoneutron dose equivalent received to the patient a Varian linac working at 18 MV photon mode investigated. Photoneutron dose equivalent measured with Polycarbonate films of 0.25 mm thick. PC films placed at distances of 0, 10, 20, and 50 cm from the center of X-ray field on the patient couch. The results show that by increasing the distance from the center of the X-ray beam towards the periphery, the photoneutron dose equivalent decreases rapidly for both open and shielded fields and that by inserting the shield in the path of the X-ray beam, the photoneutron dose equivalent was decreased obviously compared to open field. Results show the shield, significantly reduces photoneutron dose equivalent to the patient. Results can be readily generalized to other models of medical linacs. It may be concluded that using this kind of shield can help more safe, inexpensive and efficient employment of high energy linacs in radiotherapy and IMRT.

Keywords: photoneutron, Linac, PMMA shield, equivalent dose

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Authors: Tomasz Borowski, Dawid Sołoducha, Rafał Rakoczy, Marian Kordas

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The application of magnetic field is essential for a wide range of technologies or processes (i.e., magnetic hyperthermia, bioprocessing). From the practical point of view, bioprocess control is often limited to the regulation of temperature at constant values favourable to microbial growth. The main aim of this study is to determine the effect of various types of electromagnetic fields (i.e., static or alternating) on the heat transfer in a self-designed magnetically assisted reactor. The experimental set-up is equipped with a measuring instrument which controlled the temperature of the liquid inside the container and supervised the real-time acquisition of all the experimental data coming from the sensors. Temperature signals are also sampled from generator of magnetic field. The obtained temperature profiles were mathematically described and analyzed. The parameters characterizing the response to a step input of a first-order dynamic system were obtained and discussed. For example, the higher values of the time constant means slow signal (in this case, temperature) increase. After the period equal to about five-time constants, the sample temperature nearly reached the asymptotic value. This dynamical analysis allowed us to understand the heating effect under the action of various types of electromagnetic fields. Moreover, the proposed mathematical description can be used to compare the influence of different types of magnetic fields on heat transfer operations.

Keywords: heat transfer, magnetically assisted reactor, dynamical analysis, transient function

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Authors: Ndidi F. Amulu, Godian O. Mbah, Maxwel I. Onyiah, Callistus N. Ude

Abstract:

Analysis of the properties of coconut (Cocos nucifera) and its oil was evaluated in this work using standard analytical techniques. The analyses carried out include proximate composition of the fruit, extraction of oil from the fruit using different process parameters and physicochemical analysis of the extracted oil. The results showed the percentage (%) moisture, crude lipid, crude protein, ash, and carbohydrate content of the coconut as 7.59, 55.15, 5.65, 7.35, and 19.51 respectively. The oil from the coconut fruit was odourless and yellowish liquid at room temperature (30oC). The treatment combinations used (leaching time, leaching temperature and solute: solvent ratio) showed significant differences (P˂0.05) in the yield of oil from coconut flour. The oil yield ranged between 36.25%-49.83%. Lipid indices of the coconut oil indicated the acid value (AV) as 10.05 Na0H/g of oil, free fatty acid (FFA) as 5.03%, saponification values (SV) as 183.26 mgKOH-1 g of oil, iodine value (IV) as 81.00 I2/g of oil, peroxide value (PV) as 5.00 ml/ g of oil and viscosity (V) as 0.002. A standard statistical package minitab version 16.0 program was used in the regression analysis and analysis of variance (ANOVA). The statistical software mentioned above was also used to generate various plots such as single effect plot, interactions effect plot and contour plot. The response or yield of oil from the coconut flour was used to develop a mathematical model that correlates the yield to the process variables studied. The maximum conditions obtained that gave the highest yield of coconut oil were leaching time of 2 hrs, leaching temperature of 50 oC and solute/solvent ratio of 0.05 g/ml.

Keywords: coconut, oil-extraction, optimization, physicochemical, proximate

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Authors: Saraswati Verma, Ankit Batra

Abstract:

In the modern day, structures are designed with a lot of complexities due to economical, aesthetical, and functional needs causing various levels of irregularities to be induced. In the past, several studies have repeatedly shown that irregular structures suffer more damage than regular structures during earthquakes. The present study makes an effort to study the contribution of the orientation of columns in the seismic behaviour of buildings with vertical irregularities namely, soft storey irregularity, mass irregularity and geometric irregularity. The response of the various models is analysed using sap2000 version 14. The parameters through which a comparative response is investigated are displacement, variation in the stiffness contribution, and inter-storey drift. Models with different configurations of column orientations were studied for each vertical irregularity and it was observed that column orientation contributed significantly in affecting a better seismic response. Square columns of the same cross-sectional area showed a good response as compared to that of rectangular columns. The study concludes that as displacement values for buildings with a soft storey and mass irregularity are very high, square columns could be used to minimise the effect of displacement in x and y-axis. In buildings with geometric irregularity, exterior column orientations can be played with to enhance the stiffness in the shorter direction to control the displacement and drift values in both x and y directions.

Keywords: soft storey, mass irregularity, geometric irregularity, column orientation, square column

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Authors: S. Rostami, S. H. Hosseini, A. A. Torabi, M. Bekhradi

Abstract:

Introduction: Interest in the use of caffeine as an ergogenic aid has increased since the International Olympic Committee lifted the partial ban on its use. Caffeine has beneficial effects on various aspects of athletic performance, but its effects on training have been neglected. The purpose of this study was to investigate the acute effect of caffeine on testosterone and cortisole in young futsal players. Methods: Twenty-four professional futsal players with 18.3± 1.9 years ingested caffeine doses of 0, 200 and 800 mg in random order 1 hr before an anaerobic-exercise session (RAST test). Samples were taken at the time of caffeine ingestion and 30 min after the session. Data were log-transformed to estimate percent effects with mixed modeling, and effects were standardized to assess magnitudes. fects on training have been neglected. Results: Testosterone concentration showed a small increase of 15% (90% confidence limits, ± 19%) during exercise. Caffeine raised this concentration in a dose-dependent manner by a further small 21% (± 24%) at the highest dose. The 800-mg dose also produced a moderate 52% (± 44%) increase in cortisol. The effect of caffeine on the testosterone: cortisol ratio was a small decline (14%; ± 21%). Discussion and Conclusion: Caffeine has some potential to benefit training outcomes via the anabolic effects of the increase in testosterone concentration, but this benefit might be counteracted by the opposing catabolic effects of the increase in cortisol and resultant decline in the testosterone: cortisol ratio.

Keywords: anabolic, catabolic, performance, testosterone, cortisol ratio, RAST test

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Authors: Radka Pernicova

Abstract:

Chloride resistance in Ultra High Performance Concrete (UHPC) is determined in this paper. This work deals with the one dimension chloride transport, which can be potentially dangerous particularly for the durability of concrete structures. Risk of reinforcement corrosion due to exposure to the concrete surface to direct the action of chloride ions (mainly in the form de-icing salts or groundwater) is dangerously increases. The measured data are investigated depending on the depth of penetration of chloride ions into the concrete structure. Comparative measurements with normal strength concrete are done as well. The experimental results showed that UHCP have improved resistance of chlorides penetration than NSC and also chloride diffusion depth is significantly lower in UHCP.

Keywords: chloride, one dimensional diffusion, transport, salinity, UHPC

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Authors: Mouna Hamed, Ammar B. Brahim

Abstract:

The objective of this work was to develop a theoretical model to study the dynamic thermal behavior of a flat plate solar collector integrated with a phase change material (PCM). The PCM acted as a heat source for the solar system during low intensity solar radiation and night. The energy balance equations for the various components of the collector as well as for the PCM were formulated and numerically solved using MATLAB computational program. The effect of natural convection on heat during the melting process was taken into account by using an effective thermal conductivity. The model was used to investigate the effect of inlet water temperature, water mass flow rate, and PCM thickness on the outlet water temperature and the melt fraction during charging and discharging modes. A comparison with a collector without PCM was made. Results showed that charging and discharging processes of PCM have six stages. The adding of PCM caused a decrease in temperature during charge and an increase during discharge. The rise was most enhanced for higher inlet water temperature, PCM thickness and for lower mass flow rate. Analysis indicated that the complete melting time was shorter than the solidification time due to the high heat transfer coefficient during melting. The increases in PCM height and mass flow rate were not linear with the melting and solidification times.

Keywords: thermal energy storage, phase change material, melting, solidification

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Authors: Karina Marie G. Nicolas, Kimberly M. Visaya, Emmanuel R. Cauinian

Abstract:

A comparative study on the antihyperglycemic activity of aqueous extracts of Serpentina (Andrographis paniculata) and Papait (Mollugo oppositifolia linn) administered at 400mg/kg body weight per orem twice daily for 14 days was investigated using 24 alloxan-induced diabetic male, 6-8 weeks old ICR mice and Metformin as standard control. The blood glucose levels of all the animals in the treatment groups were not reduced to < 200mg/dl so as to consider them as non-diabetic but Papait showed a consistent blood glucose lowering effect from day 0 to 14 causing 36.07% reduction as compared to Serpentina which was observed to cause a fluctuating effect on blood glucose levels and a reduction of only 22.53% while the Metformin treated animals exhibited the highest reduction at 45.29%. The blood glucose levels at day 14 of animals treated with Papait (322.93 mg/dl) had comparable blood glucose levels (p<0.05) with the Metformin treated groups (284.50 mg/dl). Also, all the animals in the three treatment groups were still hypercholesterolemic with an observed consistent weight loss and a decrease in feed intake except for Serpentina which recorded a slight increase. Results of the study showed a superior antihyperglycemic activity of Papait compared with Serpentina.

Keywords: antihyperglycemic, diabetes, hypercholesterolemic, papait, serpentina

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Authors: Mohammad Aziz Shah Mohamed Arip, Aslina Ahmad, Fauziah Mohd Sa'ad, Samsiah Mohd Jais, Syed Sofian Syed Salim

Abstract:

This experimental study evaluates the effect of using Cognitive-Behavioral Therapy (CBT) and Multidimensional Self-Concept Model (MSCM) in a drug prevention programme to increase resiliency and reduce aggression among at-risk youth in Malaysia. A number of 60 (N=60) university students who were at-risk of taking drugs were involved in this study. Participants were identified with self-rating scales, Adolescent Resilience Attitude Scale (ARAS) and Aggression Questionnaire. Based on the mean score of these instruments, the participants were divided into the treatment group, and the control group. Data were analyzed using t-test. The finding showed that the mean score of resiliency was increased in the treatment group compared to the control group. It also shows that the mean score of aggression was reduced in the treatment group compared to the control group. Drug Prevention Programme was found to help in enhancing resiliency and reducing aggression among participants in the treatment group compared to the controlled group. Implications were given regarding the preventive actions on drug abuse among youth in Malaysia.

Keywords: drug prevention programme, cognitive-behavioral therapy (CBT), multidimensional self concept model (MSCM), resiliency, aggression, at-risk youth

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