Search results for: Martin Bohm

Authors: S. Singh, P. Patel, D. Kachhadiya, Swapnil Dharaskar

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The research objective is to integrate nanoparticles into fuels- i.e. diesel, biodiesel, biodiesel blended with diesel, plastic derived fuels, etc. to increase the fuel efficiency. The metal oxide nanoparticles will reduce the carbon monoxide emissions by donating oxygen atoms from their lattices to catalyze the combustion reactions and to aid complete combustion; due to this, there will be an increase in the calorific value of the blend (fuel + metal nanoparticles). Aluminium oxide and cobalt oxide nanoparticles have been synthesized by sol-gel method. The characterization was done by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). The size of the particles was determined by XRD to be 28.6 nm and 28.06 nm for aluminium oxide and cobalt oxide nanoparticles respectively. Different concentration blends- 50, 100, 150 ppm were prepared by adding the required weight of metal oxides in 1 liter of diesel and sonicating for 30 minutes at 500W. The blend properties- calorific value, viscosity, and flash point were determined by bomb calorimeter, Brookfield viscometer and pensky-martin apparatus. For the aluminum oxide blended diesel, there was a maximum increase of 5.544% in the calorific value, but at the same time, there was an increase in the flash point from 43°C to 58.5°C and an increase in the viscosity from 2.45 cP to 3.25 cP. On the other hand, for the cobalt oxide blended diesel there was a maximum increase of 2.012% in the calorific value while the flash point increased from 43°C to 51.5°C and the viscosity increased from 2.45 cP to 2.94 cP. There was a linear increase in the calorific value, viscosity and flash point when the concentration of the metal oxide nanoparticles in the blend was increased. For the 50 ppm Al₂O₃ and 50 ppm Co₃O₄ blend the increasing the calorific value was 1.228 %, and the viscosity changed from 2.45 cP to 2.64 cP and the flash point increased from 43°C to 50.5°C. Clearly the aluminium oxide nanoparticles increase the calorific value but at the cost of flash point and viscosity, thus it is better to use the 50 ppm aluminium oxide, and 50 ppm cobalt oxide blended diesel.

Keywords: aluminium oxide nanoparticles, cobalt oxide nanoparticles, fuel additives, fuel characteristics

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Authors: Ahmed Ghachem, Johann Colomba, Denis Prud'homme, Martin Brochu

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Background: Inactive obese postmenopausal women, are at greater risk for metabolic complications. On the other hand, high levels of cardiorespiratory fitness (CRF) are associated with a lower risk of metabolic complications. Objective: To compare inactive obese postmenopausal women displaying ‘lower’ vs ‘higher’ levels of CRF for body composition, metabolic profile, inflammatory profile and measures of energy expenditure. Methods: 132 women (age: 57.6 ± 4.8 yrs; BMI: 32.3 ± 4.6 kg/m2; Peak VO2: 17.81 ± 3.02 ml O2•kg-1•min-1) were studied. They were first divided into tertiles based on their CRF. Then, women in the first (< 16.51 ml O2•min-1•kg-1) and second tertiles (16.51 to 19.22 ml O2•min-1•kg-1) were combined (N= 88), and compared with those in the third tertile (> 19.22 ml O2•min-1•kg-1) (N= 44). Variables of interest were: Peak VO2 (stationary bike), body composition (DXA), body fat distribution (CT scan), glucose homeostasis (fasting state and euglycemic/ hyperinsulinemic clamp), fasting lipids, resting blood pressure, inflammatory profile and energy expenditure (DLW). Results: Both CRF groups (lower= 16.0 ± 2.0 ml O2•kg-1•min-1 vs higher= 21.2 ± 1.7 ml O2•kg-1•min-1; p < 0.001) were similar for age. Significant differences were observed between groups for body composition; with lower values for body weight, BMI, fat mass and visceral fat in women with higher CRF (p between 0.001 and 0.005). Also, women with higher CRF had lower values for fasting insulin (13.4 ± 4.5 vs 15.6 ± 6.6 μU/ml; p = 0.03) and CRP levels (2.31 ± 1.97 vs 3.83 ± 3.24 mg/liter; p = 0.001); and higher values for glucose disposal (6.71 ± 1.78 vs 5.92 ± 1.67 mg/kg/min; p = 0.01). However, these differences were no longer significant after controlling for visceral adipose tissue accumulations. Finally, no significant difference was observed between groups for the other variables of interest. Conclusion: Our results suggest that, among inactive overweight/obese postmenopausal women, those with higher CRF levels have a better metabolic profile; which is caused by lower visceral fat accumulations.

Keywords: cardiorespiratory fitness, metabolic profile, menopause, obesity

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Authors: Georgios Psakis, Imren Rahbay, David Spiteri, Jeanice Mallia, Martin Polidano, Vasilis P. Valdramidis

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Absence of surface water and progressive groundwater quality deterioration have exacerbated scarcity rapidly, making the Mediterranean island of Malta one of the most water-stressed countries in Europe. Water scarcity challenges have been addressed by reverse osmosis desalination of seawater, 60% of which is blended with groundwater to form the current potable tap-water supply. Chlorination has been the adopted method of water disinfection prior to distribution. However, with the Malteseconsumer chlorine sensory-threshold being as low as 0.34 ppm, presence of chorine residuals and chlorination by-products in the distributed tap-water impacts negatively on its organoleptic attributes, deterring the public from consuming it. As part of the PURILMA initiative, and with the aim of minimizing the impact of chlorine residual on the quality of the distributed water, UV-C, and hydrosonication, have been identified as cost- and energy-effective decontamination alternatives, paving the way for more sustainable water management. Bench-scale assessment of the decontamination efficiency of UV-C (254 nm), revealed 4.7-Log10 inactivation for both Escherichia coli and Enterococcus faecalis at 36 mJ/cm2. At >200 mJ/cm2fluence rates, there was a systematic 2-Log10 difference in the reductions exhibited by E. coli and E. faecalis to suggest that UV-C disinfection was more effective against E. coli. Hybrid treatment schemes involving hydrosonication(at 9.5 and 12.5 dm3/min flow rates with 1-5 MPa maximum pressure) and UV-C showed at least 1.1-fold greater bactericidal activity relative to the individualized UV-C treatments. The observed inactivation appeared to have stemmed from additive effects of the combined treatments, with hydrosonication-generated reactive oxygen species enhancing the biocidal activity of UV-C.

Keywords: disinfection, groundwater, hydrosonication, UV-C

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Authors: Patricia Mikchaela D. L. Feliciano, Ciela Kadeshka A. Fuentes, Bea Trixia B. Gales, Ethel Princess A. Gepulango, Martin R. Hernandez, Elina Andrea S. Lantion, Jhoe Cynder P. Legaspi, Peter F. Quilala, Gina C. Castro

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Propolis is a resin-like material used by bees to fill large gap holes in the beehive. It has been found to possess anti-inflammatory property, which stimulates hair growth in rats by inducing hair keratinocytes proliferation, causing water retention and preventing damage caused by heat, ultraviolet rays, and other microorganisms without abnormalities in hair follicles. The present study aimed to formulate 10% and 30% Propolis Hair Cream for use in enhancing hair properties. Raw propolis sample was tested for heavy metals using Atomic Absorption Spectroscopy; zinc and chromium were found to be present. Likewise, propolis was extracted in a percolator using 70% ethanol and concentrated under vacuum using a rotary evaporator. The propolis extract was analyzed for total flavonoid content. Compatibility of the propolis extract with excipients was evaluated using Differential Scanning Calorimetry (DSC). No significant changes in organoleptic properties, pH and viscosity of the formulated creams were noted after four weeks of storage at 2-8°C, 30°C, and 40°C. The formulated creams were found to be non-irritating based on the Modified Draize Rabbit Test. In vivo efficacy was evaluated based on thickness and tensile strength of hair grown on previously shaved rat skin. Results show that the formulated 30% propolis-based cream had greater hair enhancing properties than the 10% propolis cream, which had a comparable effect with minoxidil.

Keywords: atomic absorption spectroscopy, differential scanning calorimetry (DSC), modified draize rabbit test, propolis

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Authors: Matthias Feiner, Francisco Javier Fernández García, Michael Arneman, Martin Kipfmüller

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To ensure reliability in miniaturized devices or processes with increased heat fluxes, very efficient cooling methods have to be employed in order to cope with small available cooling surfaces. To address this problem, a certain type of evaporator/heat exchanger was developed: It is called a swirl evaporator due to its flow characteristic. The swirl evaporator consists of a concentrically eroded screw geometry in which a capillary tube is guided, which is inserted into a pocket hole in components with high heat load. The liquid refrigerant R32 is sprayed through the capillary tube to the end face of the blind hole and is sucked off against the injection direction in the screw geometry. Its inner diameter is between one and three millimeters. The refrigerant is sprayed into the pocket hole via a small tube aligned in the center of the bore hole and is sucked off on the front side of the hole against the direction of injection. The refrigerant is sucked off in a helical geometry (twisted flow) so that it is accelerated against the hot wall (centrifugal acceleration). This results in an increase in the critical heat flux of up to 40%. In this way, more heat can be dissipated on the same surface/available installation space. This enables a wide range of technical applications. To optimize the design for the needs in various fields of industry, like the internal tool cooling when machining nickel base alloys like Inconel 718, a correlation-based model of the swirl-evaporator was developed. The model is separated into 3 subgroups with overall 5 regimes. The pressure drop and heat transfer are calculated separately. An approach to determine the locality of phase change in the capillary and the swirl was implemented. A test stand has been developed to verify the simulation.

Keywords: helically-shaped, oil-free, R-32, swirl-evaporator, twist-flow

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Authors: Martin Mundo-Molina

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In Mexico, there are many small rural communities with serious water supply deficiencies. In Chiapas, Mexico, there are 19,972 poor rural communities, 15,712 of which have fewer than 100 inhabitants. The lack of a constant water supply is most severe in the highlands of Chiapas where the population is made up mainly of indigenous groups. The communities are on mountainous terrain with a widely dispersed population. These characteristics combine to make the provision of public utilities, such as water, electricity and sewerage, difficult with conventional means. The introduction of alternative, low-cost technologies represents means of supplying water such as through fog and rain catchment with zero greenhouse emissions. In this paper is presented the rainwater harvesting system (RWS) constructed in Yalentay, Chiapas Mexico. The RWS is able to store 1.2 M liters of water to provide drinking water to small rural indigenous communities of 500 people in the drought stage. Inside the system of rainwater harvesting there isn't photosynthesis in order to conserve water for long periods. The natural filters of the system of rainwater harvesting guarantee the drinking water for using to the community. The combination of potability and low cost makes rain collection a viable alternative for rural areas, weather permitting. The Mexican Institute of Water Technology and Chiapas University constructed a rainwater harvesting system in Yalentay Chiapas, it consists of four parts: 1. Roof of aluminum, for collecting rainwater, 2. Underground-cistern, divided in two tanks, 3. Filters, to improve the water quality and 4. The system of rainwater harvesting dignified the lives of people in Yalentay, saves energy, prevents the emission of greenhouse gases into the atmosphere, conserves natural resources such as water and air.

Keywords: appropriate technologies, climate change, greenhouse gases, rainwater harvesting

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Authors: Adjmal Ghaur, Christoph Peschel, Iris Dienwiebel, Lukas Haneke, Leilei Du , Laurin Profanter, Tobias Placke, Martin Winter

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In recent years, lithium-ion batteries (LIBs)are widely used in electric vehicles (EVs) and mobile energy storage devices (ESDs), which has led to higher requirements for energy density. To fulfill these requirements, tremendous attention has been paid to design advanced LIBs with various siliconactive materials as alternative negative electrodes to replace graphite (372 mAh g⁻¹)due to their high theoretical gravimetric capacity (4200mAh g⁻¹). However, silicon as potential anode material suffers from huge volume changes during charging and discharging and has poor electronicconductivity which negatively impacts the long-term performance and preventshigh silicon contents from practical application. Additionally, an unstable crystalline silicon structure tends to pulverization during the (de)lithiation process. To compensate for the volume changes, alleviate pulverization, and maintain high electronicconductivity, silicon-doped graphite composites with protecting coating layers are a promising approach. In this context, phosphazene compounds are investigated concerning their silicon protecting properties in silicon-doped graphite composites. In detail, electrochemical performance measurements in pouch full-cells(NCM523||SiOx/C), supressing gas formation properties, and post-mortem analyzes were carried out to characterize phosphazene compounds as additive materials. The introduction of the dual-additive approach in state-of-the-art electrolytes leads to synergistic effects between FEC and phosphazene compounds which accelerate the durability of silicon particles and results in enhanced electrochemical performance.

Keywords: silicon, phosphazene, solid electrolyte interphase, electrolyte, gasmeasurements

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Authors: Emmanuel Okine Neokye Serge Dossou Martin Iniga Bortey Nketia Alabi-Doku

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Fish stock distribution is greatly influenced by oceanographic environmental conditions. Temporal variations of temperature and other oceanic properties, resulting from climate change have been documented to have a strong impact on fisheries and aquaculture. In Ghana, Sardinella species are one of the most important fisheries resources; they constitute about 60% of the total catch of coastal fisheries and are more predominant during the upwelling season. The present study investigated the role of physical oceanographic environmental conditions in the catches of Sardinella species: S. aurita and S. maderensis, which were landed in Ghana. Furthermore, we examined the relationship between environmental conditions and catches of Sardinella species for seasonal and interannual variations between 2005 and 2015. For oceanographic environmental factors, we used comprehensive datasets, which consist of :(1) daily in situ SST data obtained at two coastal stations in Ghana; (i) Cape 3 Points (4.7° N, -2.09° W) and (ii) Tema (5° N, 0° E), for the period 2005–2015, (2) Monthly SST data (MOAA GPV) from JAMSTEC, and (3) gridded 10 metre wind data from CCMP reanalysis. The analysis of the data collected showed that higher (lower) wind velocity forms stronger (weaker) coastal upwelling that is detected by lower (higher) SST, resulting in a higher (lower) catch of Sardinella spp., in both seasonal and interannual variations. It was also observed that the capture ability of small pelagic fish species such as Sardinella spp. is depend on the intensity of the coastal upwelling. Moreso, the Atlantic Meridional Mode index (climatic index) is now known to be a possible factor to the interannual variation in catch of small pelagic fish species.

Keywords: Sardinella spp., fish, climate change, Ghana

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Authors: Wu Peng, Anders Liljerehn, Martin Magnevall

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In metal cutting, tool wear gradually changes the micro geometry of the cutting edge. Today there is a significant gap in understanding the impact these geometrical changes have on the cutting forces which governs tool deflection and heat generation in the cutting zone. Accurate models and understanding of the interaction between the work piece and cutting tool leads to improved accuracy in simulation of the cutting process. These simulations are useful in several application areas, e.g., optimization of insert geometry and machine tool monitoring. This study aims to develop an extended Kienzle force model to account for the effect of rake angle variations and tool flank wear have on the cutting forces. In this paper, the starting point sets from cutting force measurements using orthogonal turning tests of pre-machined flanches with well-defined width, using triangular coated inserts to assure orthogonal condition. The cutting forces have been measured by dynamometer with a set of three different rake angles, and wear progression have been monitored during machining by an optical measuring collaborative robot. The method utilizes the measured cutting forces with the inserts flank wear progression to extend the mechanistic cutting forces model with flank wear as an input parameter. The adapted cutting forces model is validated in a turning process with commercial cutting tools. This adapted cutting forces model shows the significant capability of prediction of cutting forces accounting for tools flank wear and different-rake-angle cutting tool inserts. The result of this study suggests that the nonlinear effect of tools flank wear and interaction between the work piece and the cutting tool can be considered by the developed cutting forces model.

Keywords: cutting force, kienzle model, predictive model, tool flank wear

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Authors: Daniel Martin, Roberto Rodriguez, Derek Woller, Chris Reuter, Lonnie Black, Mohamed Latheef

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The grasshoppers comprised of heterogeneous assemblages of Acrididae (Family: Orthoptera) species periodically reach outbreak levels by their gregarious behavior and voracious feeding habits, devouring stems and leaves of food crops and rangeland pasture. Cattle consume about 1.5-2.5% of their body weight in forage per day, so pound for pound, a grasshopper will eat 12-20 times as much plant material as a steer and cause serious economic damage to the cattle industry, especially during a drought when forage is already scarce. Grasshoppers annually consume more than 20% of rangeland forages in the western United States at an estimated loss of $1.25 billion per year in forage. A remotely piloted aerial application system with both a spreader and spray application system was used to apply granular insect bait and a liquid formulation of Carbaryl for control of grasshopper infestations on rangeland in New Mexico, United States. Pattern testing and calibration of both the granular and liquid application systems were conducted to determine proper application rate set up and distribution pattern. From these tests, an effective swath was calculated. Results showed that 14 days after application, granular baits were only effective on those grasshopper species that accepted the baits. The liquid formulation at 16 ounces per acre was highly successful at controlling all grasshopper species. Results of this study indicated that a remotely piloted aerial application system can be used to effectively deliver grasshopper control products in both granular and liquid form. However, the spray application treatment proved to be most effective and efficient for all grasshopper species present.

Keywords: Carbaryl, Grasshopper, Insecticidal Efficacy, Remotely Piloted Aerial Application System

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Authors: Cornelius Arome Omatola, Ropo Ebenezer Ogunsakin, Anyebe Bernard Onoja, Martin-Luther Oseni Okolo, Joseph Abraham-Oyiguh, Kehinde Charles Mofolorunso, Phoebe Queen Akoh, Omebije Patience Adejo, Joshua Idakwo, Therisa Ojomideju Okeme, Danjuma Muhammed, David Moses Adaji, Sunday Ocholi Samson, Ruth Aminu, Monday Eneojo Akor

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Gastroenteritis viruses are the leading etiologic agents of diarrhea in children worldwide. We present data from thirty-three (33) eligible studies published between 2003 and 2023 from African countries bearing the brunt of the virus-associated diarrheal mortality. Random effects meta-analysis with proportion, subgroups, and meta-regression analyses were employed. Overall, rotavirus with estimated pooled prevalence of 31.0% (95% CI 24.0–39.0) predominated in all primary care visits and hospitalizations, followed by norovirus, adenovirus, sapovirus, astrovirus, and aichivirus with pooled prevalence estimated at 15.0% (95% CI 12.0–20.0), 10% (95% CI 6-15), 4.0% (95% CI 2.0–6.0), 4% (95% CI 3-6), and 2.3% (95% CI 1-3), respectively. Predominant rotavirus genotype was G1P[8] (38%), followed by G3P[8] (11.7%), G9P[8] (8.7%), and G2P[4] (7.1%); although, unusual genotypes were also observed, including G3P[6] (2.7%), G8P[6] (1.7%), G1P[6] (1.5%), G10P[8] (0.9%), G8P[4] (0.5%), and G4P[8] (0.4%). The genogroup II norovirus predominated over the genogroup I-associated infections (84.6%, 613/725 vs 14.9%, 108/725), with the GII.4 (79.3%) being the most prevalent circulating genotype. In conclusion, this review showed that rotavirus remains the leading driver of viral diarrhea requiring health care visits and hospitalization among under-five years children in Africa. Thus, improved rotavirus vaccination in the region and surveillance to determine the residual burden of rotavirus and the evolving trend of other enteric viruses are needed for effective control and management of cases.

Keywords: enteric viruses, rotavirus, norovirus, adenovirus, astrovirus, gastroenteritis

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Authors: Foyezunnesa Setu, S. M. Sharifuzzaman

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Cephalopods, belonging to the taxonomic class Cephalopoda under the phylum Mollusca, have a global distribution and are particularly common in the coastal waters of Bangladesh, specifically in the southeast and southwest regions. Identifying them can be difficult due to their pliable anatomical characteristics. Due to the presence of concealed cephalopod species within the orders Sepioidea, Teuthoidea, and Octopoda, these groupings of invertebrates, which share common characteristics, are frequently misidentified as distinct entities. Until now, cephalopods have been ignored because there is not enough knowledge about the specific species and the necessary preliminary research has not been done. This study offers a systematic description of various cephalopod species found along the south eastern coast of Bangladesh. A combined total of 25 cuttlefish specimens, four squid specimens, and five octopus specimens were gathered from the shores of Saint Martin's Island and Cox's Bazar. Based on morphological analysis, a total of 14 cephalopod species are identified. These species include Sepia aculeata, Sepia esculenta, Sepia pharaonis, Sepia prashadi, Sepiella inermis, Sepiella japonica, Uroteuthis duvauceli, Doryteuthis singhalensis, Sepioteuthis sepioidea, Eupryma stenodactyla, Amphioctopus aegina, Callistoctopus macropus, Octopus ceynea, and Octopus vulgaris. Six newly discovered species, including Sepia prashadi, Sepiella japonica, Sepioteuthis sepioidea, Eupryma stenodactyla, Callistoctopus macropus, and Octopus ceynea, have been identified in Bangladesh. Taxonomically, the identification of cephalopods is difficult due to the significant resemblance between species and the scarcity of information and preparatory research. This study offers significant insights about the cephalopod fauna found in the northern region of the Bay of Bengal.

Keywords: cephalopods, new records, northern bay of bengal, taxonomic identification

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Authors: Pragathi Gurumurthy, Christina Hagen, Patricia Ulloa, Martin A. Koch, Thorsten M. Buzug

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Obstructive sleep apnea (OSA) is a sleep disorder where the patient suffers a disturbed airflow during sleep due to partial or complete occlusion of the pharyngeal airway. Recently, numerical simulations have been used to better understand the mechanism of pharyngeal collapse. However, to gain confidence in the solutions so obtained, an experimental validation is required. Therefore, in this study an experimental validation of computational fluid dynamics (CFD) used for the study of human pharyngeal flow patterns during OSA is performed. A stationary incompressible Navier-Stokes equation solved using the finite element method was used to numerically study the flow patterns in a computed tomography-based human pharynx model. The inlet flow rate was set to 250 ml/s and such that a flat profile was maintained at the inlet. The outlet pressure was set to 0 Pa. The experimental technique used for the validation of CFD of fluid flow patterns is phase contrast-MRI (PC-MRI). Using the same computed tomography data of the human pharynx as in the simulations, a phantom for the experiment was 3 D printed. Glycerol (55.27% weight) in water was used as a test fluid at 25°C. Inflow conditions similar to the CFD study were simulated using an MRI compatible flow pump (CardioFlow-5000MR, Shelley Medical Imaging Technologies). The entire experiment was done on a 3 T MR system (Ingenia, Philips) with 108 channel body coil using an RF-spoiled, gradient echo sequence. A comparison of the axial velocity obtained in the pharynx from the numerical simulations and PC-MRI shows good agreement. The region of jet impingement and recirculation also coincide, therefore validating the numerical simulations. Hence, the experimental validation proves the reliability and correctness of the numerical simulations.

Keywords: computational fluid dynamics, experimental validation, phase contrast-MRI, obstructive sleep apnea

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Authors: Henry Navarro, Martin Sirena, Nestor Haberkorn

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We report the electrical transport through voltage-current curves (I-V) in tunnels junction GdBa₂Cu₃O₇-d/ insulator/ GdBa₂Cu₃O₇-d, and Nb/insulator/ GdBa₂Cu₃O₇-d is analyzed using a conducting atomic force microscope (CAFM) at room temperature. The measurements were obtained on tunnel junctions with different areas (900 μm², 400 μm² and 100 μm²). Trilayers with GdBa₂Cu₃O₇-d (GBCO) as the bottom electrode, SrTiO₃ (STO) or BaTiO₃ (BTO) as the insulator barrier (thicknesses between 1.6 nm and 4 nm), and GBCO or Nb as the top electrode were grown by DC sputtering on (100) SrTiO₃ substrates. For STO and BTO barriers, asymmetric IV curves at positive and negative polarization can be obtained using electrodes with different work function. The main difference is that the BTO is a ferroelectric material, while in the STO the ferroelectricity can be produced by stress or deformation at the interfaces. In addition, hysteretic IV curves are obtained for BTO barriers, which can be ascribed to a combined effect of the FE reversal switching polarization and an oxygen vacancy migration. For GBCO/ BTO/ GBCO heterostructures, the IV curves correspond to that expected for asymmetric interfaces, which indicates that the disorder affects differently the properties at the bottom and top interfaces. Our results show the role of the interface disorder on the electrical transport of conducting/ insulator/ conduction heterostructures, which is relevant for different applications, going from resistive switching memories (at room temperature) to Josephson junctions (at low temperatures). The superconducting transition of the GBCO electrode was characterized by electrical transport using the 4-prong configuration with low density of topological defects and with Tc over liquid N₂ can be obtained for thicknesses of 16 nm, our results demonstrate that GBCO films with an average root-mean-square (RMS) smaller than 1 nm and areas (up 100 um²) free of 3-D topological defects can be obtained.

Keywords: thin film, sputtering, conductive atomic force microscopy, tunnel junctions

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Authors: Amira ben Hassine, A. Valverde, V. Serafín, C. Muñoz-San Martín, M. Garranzo-Asensio, M. Gamella, R. Barderas, M. Pedrero, N. Raouafi, S. Campuzano, P. Yáñez-Sedeño, J. M. Pingarrón

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This work describes the development of a dual electrochemical immunosensing platform for accurate determination of two target proteins, IL-13 Receptor α2 (IL-13Rα2) and E-cadherin (E-cad). The proposed methodology is based on the use of sandwich immunosensing approaches (involving horseradish peroxidase-labeled detector antibodies) implemented onto magnetic microbeads (MBs) and amperometric transduction at screen-printed dual carbon electrodes (SPdCEs). The magnetic bioconjugates were captured onto SPdCEs and the amperometric transduction was performed using the H2O2/hydroquinone (HQ) system. Under optimal experimental conditions, the developed bio platform demonstrates linear concentration ranges of 1.0–25 and 5.0-100 ng mL-1, detection limits of 0.28 and 1.04 ng mL-1 for E-cad and IL-13Rα2, respectively, and excellent selectivity against other non-target proteins. The developed immuno-platform also offers a good reproducibility among amperometric responses provided by nine different sensors constructed in the same manner (Relative Standard Deviation values of 3.1% for E-cad and 4.3% for IL-13Rα2). Moreover, obtained results confirm the practical applicability of this bio-platform for the accurate determination of the endogenous levels of both extracellular receptors in colon cancer cells (both intact and lysed) with different metastatic potential and serum and tissues from patients diagnosed with colorectal cancer at different grades. Interesting features in terms of, simplicity, speed, portability and sample amount required to provide quantitative results, make this immuno-platform more compatible than conventional methodologies with the clinical diagnosis and prognosis at the point of care.

Keywords: electrochemistry, mmunosensors, biosensors, E-cadherin, IL-13 receptor α2, cancer colorectal

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Authors: Amit Syal, Madeline Grade, Alister Martin

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Background: Cross-sectional and longitudinal studies demonstrate an association between health and voting. Furthermore, voting enables populations to support policies that impact their health via social determinants like income, education, housing, and healthcare access. Unfortunately, many barriers exist which disproportionately affect the civic participation of certain minority groups. Health professionals have an important role to play in addressing the civic health of all patients and empowering underrepresented communities. Description: Vot-ER is a non-partisan, nonprofit organization that aims to reduce barriers to civic participation by helping patients register to vote while in healthcare settings. The initial approach involved iPad-based kiosks in the emergency department waiting rooms, allowing patients to register themselves while waiting. After the COVID-19 pandemic began, Vot-ER expanded its touchless digital approaches. Vot-ER provides healthcare workers across the country with “Healthy Democracy Kits” consisting of badge backers, posters, discharge paperwork, and other resources. These contain QR and text codes that direct users to an online platform for registering to vote or requesting a mail-in ballot, available in English or Spanish. Outcomes: From May to November 2020, Vot-ER helped prepare 46,320 people to vote. 13,192 individual healthcare providers across all 50 states signed up for and received Healthy Democracy Kits. 80 medical schools participated in the Healthy Democracy Campaign competition. Over 500 institutions ordered site-based materials. Conclusions: A healthy democracy is one in which all individuals in a community have equal and fair opportunities for their voices to be heard. Healthcare settings, such as hospitals, are appropriate and effective venues for increasing both voter registration and education.

Keywords: civic health, enfranchisement, physician, voting

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Authors: Jay Martin L. Dionaldo

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This study aimed to develop a causal model on the performance of the basic education teachers in the Division of Malaybalay City for the school year 2018-2019. This study used the responses of 300 randomly selected basic education teachers of Malaybalay City, Bukidnon. They responded to the three sets of questionnaires patterned from the National Education Association (2018) on instructional leadership of teachers, the questionnaire of Caluza et al., (2017) for information and communications technology competencies and the questionnaire on the teachers’ performance using the Individual Performance Commitment and Review Form (IPCRF) adopted by the Department of Education (DepEd). Descriptive statistics such as mean for the description, correlation for a relationship, regression for the extent influence, and path analysis for the model that best fits teachers’ performance were used. Result showed that basic education teachers have a very satisfactory level of performance. Also, the teachers highly practice instructional leadership practices in terms of coaching and mentoring, facilitating collaborative relationships, and community awareness and engagement. On the other hand, they are proficient users of ICT in terms of technology operations and concepts and basic users in terms of their pedagogical indicators. Furthermore, instructional leadership, coaching and mentoring, facilitating collaborative relationships and community awareness and engagement and information and communications technology competencies; technology operations and concept and pedagogy were significantly correlated toward teachers’ performance. Coaching and mentoring, community awareness and engagement, and technology operations and concept were the best predictors of teachers’ performance. The model that best fit teachers’ performance is anchored on coaching and mentoring of the teachers, embedded with facilitating collaborative relationships, community awareness, and engagement, technology operations, and concepts, and pedagogy.

Keywords: information and communications technology, instructional leadership, coaching and mentoring, collaborative relationship

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Authors: Martin Hofmann, Diego Stutzer, Thomas Niederhauser, Juergen Burger

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Dental biofilm is the main etiologic factor for caries, periodontal and peri-implant infections. In addition to the risk of tooth loss, periodontitis is also associated with an increased risk of systemic diseases such as atherosclerotic cardiovascular disease and diabetes. For this reason, dental hygienists use ultrasonic scalers for prophylactic and periodontal care of the teeth. However, the current instruments are limited to their dimensions and operating frequencies. The innovative design of a planar ultrasonic transducer introduces a new type of dental scalers. The flat titanium-based design allows the mass to be significantly reduced compared to a conventional screw-mounted Langevin transducer, resulting in a more efficient and controllable scaler. For the development of the novel device, multi-physics finite element analysis was used to simulate and optimise various design concepts. This process was supported by prototyping and electromechanical characterisation. The feasibility and potential of a planar ultrasonic transducer have already been confirmed by our current prototypes, which achieve higher performance compared to commercial devices. Operating at the desired resonance frequency of 28 kHz with a driving voltage of 40 Vrms results in an in-plane tip oscillation with a displacement amplitude of up to 75 μm by having less than 8 % out-of-plane movement and an energy transformation factor of 1.07 μm/mA. In a further step, we will adapt the design to two additional resonance frequencies (20 and 40 kHz) to obtain information about the most suitable mode of operation. In addition to the already integrated characterization methods, we will evaluate the clinical efficiency of the different devices in an in vitro setup with an artificial biofilm pocket model.

Keywords: ultrasonic instrumentation, ultrasonic scaling, piezoelectric transducer, finite element simulation, dental biofilm, dental calculus

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Authors: Martin Botz, Michael Kraus, Geralt Siebert

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The use of laminated glass gains increasing importance in structural engineering. For safety reasons, at least two glass panes are laminated together with a polymeric interlayer. In case of breakage of one or all of the glass panes, the glass fragments are still connected to the interlayer due to adhesion forces and a certain residual load-bearing capacity is left in the system. Polymer interlayers used in the laminated glass show a viscoelastic material behavior, e.g. stresses and strains in the interlayer are dependent on load duration and temperature. In the intact stage only small strains appear in the interlayer, thus the material can be described in a linear way. In the broken stage, large strains can appear and a non-linear viscoelasticity material theory is necessary. Relaxation tests on two different types of polymeric interlayers are performed at different temperatures and strain amplitudes to determine the border to the non-linear material regime. Based on the small-scale specimen results further tests on broken laminated glass panes are conducted. So-called ‘through-crack-bending’ (TCB) tests are performed, in which the laminated glass has a defined crack pattern. The test set-up is realized in a way that one glass layer is still able to transfer compressive stresses but tensile stresses have to be transferred by the interlayer solely. The TCB-tests are also conducted under different temperatures but constant force (creep test). Aims of these experiments are to elaborate if the results of small-scale tests on the interlayer are transferable to a laminated glass system in the broken stage. In this study, limits of the applicability of linear-viscoelasticity are established in the context of two commercially available polymer-interlayers. Furthermore, it is shown that the results of small-scale tests agree to a certain degree to the results of the TCB large-scale experiments. In a future step, the results can be used to develop material models for the post breakage performance of laminated glass.

Keywords: glass breakage, laminated glass, relaxation test, viscoelasticity

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Authors: Hyelim Park, Juan Martin Zorrilla

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Climate change influences very widely and in various ways ocean ecosystem functioning. The consequences of climate change on marine ecosystems are an increase in temperature and irregular behavior of some solute concentrations. These changes would affect fisheries catches in several ways. Our aim is to assess the quantitative contribution change of fishery catches along the time and express them through four environment variables: Sea Surface Temperature (SST4) and the concentrations of Chlorophyll (CHL), Particulate Inorganic Carbon (PIC) and Particulate Organic Carbon (POC) at two spatial scales: Global and the nineteen FAO Major Fishing Areas divisions. Data collection was based on the FAO FishStatJ 2014 database as well as MODIS Aqua satellite observations from 2002 to 2012. Some data had to be corrected and interpolated using some existing methods. As the results, a multivariable regression model for average Global fisheries captures contained temporal mean of SST4, standard deviation of SST4, standard deviation of CHL and standard deviation of PIC. Global vector auto-regressive (VAR) model showed that SST4 was a statistical cause of global fishery capture. To accommodate varying conditions in fishery condition and influence of climate change variables, a model was constructed for each FAO major fishing area. From the management perspective it should be recognized some limitations of the FAO marine areas division that opens to possibility to the discussion of the subdivision of the areas into smaller units. Furthermore, it should be treated that the contribution changes of fishery species and the possible environment factor for specific species at various scale levels.

Keywords: fisheries-catch, FAO FishStatJ, MODIS Aqua, sea surface temperature (SST), chlorophyll, particulate inorganic carbon (PIC), particulate organic carbon (POC), VAR, granger causality

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Authors: A. Aslihan Gokaltun, Martin L. Yarmush, Ayse Asatekin, O. Berk Usta

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In the last decade microfabrication processes including rapid prototyping techniques have advanced rapidly and achieved a fairly matured stage. These advances encouraged and enabled the use of microfluidic devices by a wider range of users with applications in biological separations, and cell and organoid cultures. Accordingly, a significant current challenge in the field is controlling biomolecular interactions at interfaces and the development of novel biomaterials to satisfy the unique needs of the biomedical applications. Poly(dimethylsiloxane) (PDMS) is by far the most preferred material in the fabrication of microfluidic devices. This can be attributed its favorable properties, including: (1) simple fabrication by replica molding, (2) good mechanical properties, (3) excellent optical transparency from 240 to 1100 nm, (4) biocompatibility and non-toxicity, and (5) high gas permeability. However, high hydrophobicity (water contact angle ~108°±7°) of PDMS often limits its applications where solutions containing biological samples are concerned. In our study, we created a simple, easy method for modifying the surface chemistry of PDMS microfluidic devices through the addition of surface-segregating additives during manufacture. In this method, a surface segregating copolymer is added to precursors for silicone and the desired device is manufactured following the usual methods. When the device surface is in contact with an aqueous solution, the copolymer self-organizes to expose its hydrophilic segments to the surface, making the surface of the silicone device more hydrophilic. This can lead to several improved performance criteria including lower fouling, lower non-specific adsorption, and better wettability. Specifically, this approach is expected to be useful for the manufacture of microfluidic devices. It is also likely to be useful for manufacturing silicone tubing and other materials, biomaterial applications, and surface coatings.

Keywords: microfluidics, non-specific protein adsorption, PDMS, PEG, copolymer

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Authors: Nathalie Bolding, Marta Montero, Joaquim Cevallos, Juan F. Martin-Lazaro

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Background: Inhaled epoprostenol (iEPO) have been shown to improve PaO2:FiO2 (PF) in combination with bronchodilators (BD). However, there is not an available device to deliver these two therapies concomitantly. We describe a new method to provide this therapy successfully. Objective: To evaluate the response to continuous nebulization of iEPO and intermittent nebulization of Salbutamol/Ipratropium bromide in adults with severe respiratory failure through a double mesh nebulisation in tandem. Methods: This observational study included two mechanical ventilated adults under hourly ventilatory, gasometrical and clinical measurements during 48h. Both had severe respiratory failure treated with continuous iEPO (50 – 200 micrograms/h) and BD (Salbutamol 2.5 mg and Ipratropium bromide 500 mcg every 6 hours) through double mesh nebulisation (Aerogen solo®) placed in tandem in the dry side of the humidificator. The primary endpoints were the variables associated with a positive response to this tandem nebulised therapy (PaFiO2 index, ROX index). Secondary endpoints were laboratory (ABG) clinical and ventilatory variables. Statistical analysis (SPSS v29) included linear regression and ANOVA. Results: The patients included (n=2) survived, both extubated, one after ECMO therapy. Severe acute respiratory failure had a positive response rate to continuous iEPO and intermittent BD: PaFiO2 increased (7.40 to 30.91; P75: 27%) as well as ROX index (2.91 to 11.43; P75: 33%). There was a linear correlation of improvement between iEPO with PaFiO2 (ANOVA, r=0.393, p<0.002) and ROX (r=0.419, p<0.001). iEPO+BD therapy did not show any complications. Conclusion: Continuous and intermittent mesh tandem nebulisation can be effectively delivered with this method with a positive effect in ventilatory parameters without observed complications. Randomised studies will be able to provide reassurance in this new therapy.

Keywords: tandem, mesh, nebulisers, pulmonary, vasoldilators, bronchodilators, respiratory, failure

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Authors: Hosam Alzahrani, Martin Mackey, Emmanuel Stamatakis, Marina B. Pinheiro, Manuela Wicks, Debra Shirley

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Objective: To investigate the effectiveness of incidental (non-structured) physical activity interventions compared with other commonly prescribed interventions for the management of people with low back pain (LBP). Methods: We performed a systematic review with meta-analyses of eligible randomized controlled trials obtained by searching Medline, Scopus, CINAHL, EMBASE, and CENTRAL. This review considered trials investigating the effect of incidental physical activity interventions compared to other interventions in people aged 18 years or over, diagnosed with non-specific LBP. Analyses were conducted separately for short-term (≤3 months), intermediate-term (> 3 and < 12 months), and long-term (≥ 12 months), for each outcome. The analyses were conducted using the weighted mean difference (WMD). The overall quality of evidence was assessed using the GRADE system. Meta-analyses were only performed for pain and disability outcomes as there was insufficient data on the other outcomes. Results: For pain, the pooled results did not show any significant effects between the incidental physical activity intervention and other interventions at any time point. For disability, incidental physical activity was not statistically more effective than other interventions at short-term; however, the pooled results favored incidental physical activity at intermediate-term (WMD= -6.05, 95% CI: -10.39 to -1.71, p=0.006) and long-term (WMD= -6.40 95% CI: -11.68 to -1.12, p=0.02) follow-ups among participants with chronic LBP. The overall quality of evidence was rated “moderate quality” based on the GRADE system. Conclusion: The incidental physical activity intervention provided intermediate and long disability relief for people with chronic LBP, although this improvement was small and not likely to be clinically important.

Keywords: physical activity, incidental, low back pain, systematic review, meta-analysis

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Authors: Waqqas-ur-Rehman Butt, Martin Servin, Marion Pause

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In recent years, object detection has gained much attention and very encouraging research area in the field of computer vision. The robust object boundaries detection in an image is demanded in numerous applications of human computer interaction and automated surveillance systems. Many methods and approaches have been developed for automatic object detection in various fields, such as automotive, quality control management and environmental services. Inappropriately, to the best of our knowledge, object detection under illumination with shadow consideration has not been well solved yet. Furthermore, this problem is also one of the major hurdles to keeping an object detection method from the practical applications. This paper presents an approach to automatic object detection in images under non-standardized environmental conditions. A key challenge is how to detect the object, particularly under uneven illumination conditions. Image capturing conditions the algorithms need to consider a variety of possible environmental factors as the colour information, lightening and shadows varies from image to image. Existing methods mostly failed to produce the appropriate result due to variation in colour information, lightening effects, threshold specifications, histogram dependencies and colour ranges. To overcome these limitations we propose an object detection algorithm, with pre-processing methods, to reduce the interference caused by shadow and illumination effects without fixed parameters. We use the Y CrCb colour model without any specific colour ranges and predefined threshold values. The segmented object regions are further classified using morphological operations (Erosion and Dilation) and contours. Proposed approach applied on a large image data set acquired under various environmental conditions for wood stack detection. Experiments show the promising result of the proposed approach in comparison with existing methods.

Keywords: image processing, illumination equalization, shadow filtering, object detection

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Authors: Camilo A. Guerrero-Martin, Erik Montes Paez, Marcia C. K. Oliveira, Jonathan Campos, Elizabete F. Lucas

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Asphaltenes precipitation is considered as a formation damage problem, which can reduce the oil recovery factor. It fouls piping and surface installations, as well as cause serious flow assurance complications and decline oil well production. Therefore, researchers have shown an interest in chemical treatments to control this phenomenon. The aim of this paper is to assess the asphaltenes precipitation onset of crude oils in the presence of cardanol, by titrating the crude with n-heptane. Moreover, based on this results obtained at atmosphere pressure, the asphaltenes precipitation onset pressure were calculated to predict asphaltenes precipitation in the reservoir, by using differential liberation and refractive index data of the oils. The influence of cardanol concentrations in the asphaltenes stabilization of three Brazilian crude oils samples (with similar API densities) was studied. Therefore, four formulations of cardanol in toluene were prepared: 0, 3, 5, 10 and 15 m/m%. The formulations were added to the crude at 2:98 ratio. The petroleum samples were characterized by API density, elemental analysis and differential liberation test. The asphaltenes precipitation onset (APO) was determined by titrating with n-heptane and monitoring with near-infrared (NIR). UV-Vis spectroscopy experiments were also done to assess the precipitate asphaltenes content. The asphaltenes precipitation envelopes (APE) were also determined by numerical simulation (Multiflash). In addition, the adequate artificial lift systems (ALS) for the oils were selected. It was based on the downhole well profile and a screening methodology. Finally, the oil flowrates were modelling by NODAL analysis production system in the PIPESIM software. The results of this study show that the asphaltenes precipitation onset of the crude oils were 2.2, 2.3 and 6.0 mL of n-heptane/g of oil. The cardanol was an effective inhibitor of asphaltenes precipitation for the crude oils used in this study, since it displaces the precipitation pressure of the oil to lower values. This indicates that cardanol can increase the oil wells productivity.

Keywords: asphaltenes, NODAL analysis production system, precipitation pressure onset, inhibitory molecule

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Authors: Martin C. Eze, Gao Min

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Lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) dopant is beneficial in improving the properties of 2,2′,7,7′-Tetrakis (N, N-di-p-methoxyphenylamino)-9,9′-spiro-bifluorene (Spiro-OMETAD) transport layer used in perovskite solar cells (PSCs). Properties such as electrical conductivity, band energy mismatch, and refractive index of Spiro-OMETAD layers are believed to play key roles in PSCs performance but only the dependence of electrical conductivity on Li-TFSI doping has been extensively studied. In this work, the effect of Li-TFSI doping level on highest occupied molecular orbital (HOMO) energy, electrical conductivity, and refractive index of Spiro-OMETAD film and PSC performance was demonstrated. The Spiro-OMETAD films were spin-coated at 4000 rpm for 30 seconds from solutions containing 73.4 mM of Spiro-OMeTAD, 23.6 mM of 4-tert-butylpyridine, 7.6 mM of tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine) cobalt(III) tri[bis(trifluoromethane) sulfonimide] (FK209) dopant and Li-TFSI dopant varying from 37 to 62 mM in 1 ml of chlorobenzene. From ultraviolet photoelectron spectroscopy (UPS), ellipsometry, and 4-probe studies, the results show that films deposition from Spiro-OMETAD solution doped with 40 mM of Li-TFSI shows the highest electrical conductivity of 6.35×10-6 S/cm, the refractive index of 1.87 at 632.32 nm, HOMO energy of -5.22 eV and the lowest HOMO energy mismatch of 0.21 eV compared to HOMO energy of perovskite layer. The PSCs fabricated show the best power conversion efficiency, open-circuit voltage, and fill factor of 17.10 %, 1.1 V, and 70.12%, respectively, for devices based on Spiro-OMETAD solution doped with 40 mM of Li-TFSI. This study demonstrates that the optimum Spiro-OMETAD/ Li-TFSI doping ratio of 1.84 is the optimum doping level for Spiro-OMETAD layer preparation.

Keywords: electrical conductivity, homo energy mismatch, lithium bis(trifluoromethanesulfonyl)imide, power conversion efficiency, refractive index

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Authors: Stefaan Carpentier, Aya Al Masri, Fabrice Leroy, Thibault Julien, Safoin Aktaou, Malorie Martin, Fouad Maaloul

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Introduction: During an 'Interventional Radiology (IR)' procedure, the patient's skin-dose may become very high for a burn, necrosis, and ulceration to appear. In order to prevent these deterministic effects, a prediction of the peak skin-dose for the patient is important in order to improve the post-operative care to be given to the patient. The objective of this study is to estimate, before the intervention, the patient dose for ‘Chronic Total Occlusion (CTO)’ procedures by selecting relevant clinical indicators. Materials and methods: 103 procedures were performed in the ‘Interventional Cardiology (IC)’ department using a Siemens Artis Zee image intensifier that provides the Air Kerma of each IC exam. Peak Skin Dose (PSD) was measured for each procedure using radiochromic films. Patient parameters such as sex, age, weight, and height were recorded. The complexity index J-CTO score, specific to each intervention, was determined by the cardiologist. A correlation method applied to these indicators allowed to specify their influence on the dose. A predictive model of the dose was created using multiple linear regressions. Results: Out of 103 patients involved in the study, 5 were excluded for clinical reasons and 2 for placement of radiochromic films outside the exposure field. 96 2D-dose maps were finally used. The influencing factors having the highest correlation with the PSD are the patient's diameter and the J-CTO score. The predictive model is based on these parameters. The comparison between estimated and measured skin doses shows an average difference of 0.85 ± 0.55 Gy for doses of less than 6 Gy. The mean difference between air-Kerma and PSD is 1.66 Gy ± 1.16 Gy. Conclusion: Using our developed method, a first estimate of the dose to the skin of the patient is available before the start of the procedure, which helps the cardiologist in carrying out its intervention. This estimation is more accurate than that provided by the Air-Kerma.

Keywords: chronic total occlusion procedures, clinical experimentation, interventional radiology, patient's peak skin dose

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Authors: Mahdi PourAsghar, Abbas Mas'udzadeh, Abdulhakim Tirgari, Saeed Dabiri Roushan, Hooman Rashidi, Fariba Salehi

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Objective: One of the major objectives in sports areas is to achieve maximum athletic performance. Physical and psychological preparations are the basic factors for achieving maximum performance in athletes. Unfortunately, in the field of physical preparation, we can see maximum attention and planning of trainers and sports officials. But despite the importance of psychological preparation of athletes and its serious and profound effect on athletic performance, the results of sports competitions show that less attention is paid to this topic, and it is less under the control of counselors and psychologists in different areas of our sport. Therefore, this study aimed to evaluate the attitude of athletes and coaches to sport psychology. Materials and methods: A descriptive study with a sample size of 234 elite athletes and 216 skilled coaches was conducted in different areas of sports, in Sari, Mazandaran in 2015.The instrument was a questionnaire consisting of two parts of demographic data and Martin questionnaire, assessing the attitude to sport psychology. The data from this study were analyzed using Spss version 18, descriptive statistics tests, and Chi-square test. Results: In this study, positive attitudes of participants in need and confidence towards sport psychology consultation in athletes and coaches group were 55/1 and 56/5 percent, respectively. The positive attitude of female athletes in belief to psychology consultation was more than male athletes. Athletes with higher education had more positive attitude towards the presence of psychologists and psychiatrists in fields of sports. Conclusion: According to the findings based on the need to the psychology consultation in different areas of sports, it is recommended that through training of specialists in the field of sport psychology and review of sports programs in different fields of sports, the presence of these counselors to maintain the psychological preparation of athletes to achieve maximum athletic performance and reduce anxiety and stress be used.

Keywords: Keywords: Athletes, Eliteathletes, Coaches, Attitude, Sport psychology.

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Authors: Jorge Anibal Restrepo Morales, Sonia Martín Gómez

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A model based on a logical framework was developed to quantify SMEs' internationalization capacity. To do so, linguistic variables, such as human talent, infrastructure, innovation strategies, FTAs, marketing strategies, finance, etc. were integrated. It is argued that a company’s management of international markets depends on internal factors, especially capabilities and resources available. This study considers internal factors as the biggest business challenge because they force companies to develop an adequate set of capabilities. At this stage, importance and strategic relevance have to be defined in order to build competitive advantages. A fuzzy inference system is proposed to model the resources, skills, and capabilities that determine the success of internationalization. Data: 157 linguistic variables were used. These variables were defined by international trade entrepreneurs, experts, consultants, and researchers. Using expert judgment, the variables were condensed into18 factors that explain SMEs’ export capacity. The proposed model is applied by means of a case study of the textile and clothing cluster in Medellin, Colombia. In the model implementation, a general index of 28.2 was obtained for internationalization capabilities. The result confirms that the sector’s current capabilities and resources are not sufficient for a successful integration into the international market. The model specifies the factors and variables, which need to be worked on in order to improve export capability. In the case of textile companies, the lack of a continuous recording of information stands out. Likewise, there are very few studies directed towards developing long-term plans, and., there is little consistency in exports criteria. This method emerges as an innovative management tool linked to internal organizational spheres and their different abilities.

Keywords: business strategy, exports, internationalization, fuzzy set methods

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Authors: Amani Kappi, Ana Maria Linares, Gia Mudd-Martin

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Children with Attention Deficit Hyperactivity Disorder (ADHD) are more likely to develop social skills deficits that can lead to academic underachievement, peer rejection, and maladjustment. Surveying teachers about children's social skills with ADHD will become a significant factor in identifying whether the children will be diagnosed with social skills deficits. The teacher-specific version of the Social Skills Rating System scale (SSRS-T) has been used as a screening tool for children's social behaviors. The psychometric properties of the SSRS-T have been evaluated in various populations and settings, such as when used by teachers to assess social skills for children with learning disabilities. However, few studies have been conducted to examine the psychometric properties of the SSRS-T when used to assess children with ADHD. The purpose of this study was to examine the psychometric properties of the SSRS-T and two SSRS-T subscales, Social Skills and Problem Behaviors. This was a secondary analysis of longitudinal data from the Fragile Families and Child Well-Being Study. This study included a sample of 194 teachers who used the SSRS-T to assess the social skills of children aged 8 to 10 years with ADHD. Exploratory principal components factor analysis was used to assess the construct validity of the SSRS-T scale. Cronbach’s alpha value was used to assess the internal consistency reliability of the total SSRS-T scale and the subscales. Item analyses included item-item intercorrelations, item-to-subscale correlations, and Cronbach’s alpha value changes with item deletion. The results of internal consistency reliability for both the total scale and subscales were acceptable. The results of the exploratory factor analysis supported the five factors of SSRS-T (Cooperation, Self-control, Assertion, Internalize behaviors, and Externalize behaviors) reported in the original version. Findings indicated that SSRS-T is a reliable and valid tool for assessing the social behaviors of children with ADHD.

Keywords: ADHD, children, social skills, SSRS-T, psychometric properties

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