Search

Copyright of Canadian Journal of Ophthalmology is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Forced convective heat transfer of ferrofluid was studied experimentally under constant and oscillating magnetic fields. • Nanoparticle responses to different magnetic field applications are photographed. • A phase shift approach in oscillating magnetic field is implemented for heat transfer enhancement. • Implementation of magnetic phase shift led to highest heat transfer enhancements. • Local and average Nusselt numbers were enhanced by a maximum of 73% and 36% respectively, under oscillating magnetic fields with 90 and 180° phase shifts. In this study, laminar flow and forced convective heat transfer of water-based ferrofluids flowing through a uniformly heated pipe are experimentally investigated under the presence of phase-shifted oscillating magnetic fields. To investigate the effect of phase shift on heat transfer, electromagnets are positioned along the tube, and oscillating magnetic fields are applied with various phase shift angles between opposing magnetic poles. Experiments are conducted for different Reynolds numbers (400 to 1000), magnetic field frequencies (0 Hz, 1 Hz, and 5 Hz), phase shift angles (0°, 90°, and 180°), and nanoparticle volume fractions (0.5 % and 1 %). For each parameter set, local and average Nusselt numbers, as well as pressure drop values, are determined, and the effect of applied magnetic fields on the heat transfer rate is extensively discussed. Results showed that, applying an external magnetic field resulted in significant enhancements in the forced convective heat transfer of ferrofluid. Under an oscillating magnetic field with 0° phase shift, maximum of 40 % and 20.6 % enhancements were observed in local and average Nusselt numbers respectively under the investigated parameters. Furthermore, applying oscillating magnetic fields with a phase shift between opposing poles caused significant fluctuations in the fluid, led to remarkable improvements in convective heat transfer rates. For 90° and 180° phase shifts, enhancements in local and average Nusselt numbers were observed to increase up to 73 % and 36 %, respectively. [ABSTRACT FROM AUTHOR]

• PCM based heat sinks on the thermal regulation of PVs are experimentally studied. • Proposed heat sinks with open ended air channels inside PCM layer is utilized. • The number and diameter of air channels is found to be significant in heat sink performance. • Thermal regulation and discharge periods are enhanced. In this study, a novel parametric investigation was conducted to enhance the performance of conventional PCM-based heat sinks utilized for thermal regulation in PV panels. The proposed heat sinks in this study aimed to address some issues reported in the literature by offering prolonged thermal regulation periods, reduced PV temperatures, and accelerated discharge rates through utilization of ambient air and PCM for passive heat dissipation. These enhancements were achieved by integrating several open ended pipes into the PCM layer, enabling passive removal of a portion of stored heat in the PCM by ambient air. The investigation comprised five study cases: Case 1 (reference PV), Case 2 (conventional-PV-PCM), and the proposed heat sinks: Case 3 (6-piped-PV-PCM), Case 4 (10-piped-PV-PCM), and Case 5 (14-piped-PV-PCM). In the study, the enhancements in thermal regulation periods, PV temperatures, power outputs and discharge rates were experimentally investigated for each case. Experiments were conducted in a laboratory setting under constant irradiation of 1000 W/m2, ambient temperature of 25 °C, and three tilt angles (30°-45°-90°). The results indicated that integration of open-ended pipes within the PCM layer showed promise in passive heat removal from the PCM and led to remarkable enhancements in thermal and electrical performance. Experiments for 7-hour irradiation period demonstrated that proposed heat sinks passively extended the thermal regulation period by 45 %, reduced the maximum PV temperature by 11 °C, shortened the solidification times by 36.5 %, and enhanced the total electrical output by 4.37 %. [ABSTRACT FROM AUTHOR]

Microfluidization can produce highly stable and homogenous aqueous media, even when the sample consists of hydrophobic and nonpolar components, due to its combined forces like ultra-high-pressure, high-velocity impact, cavitation, and intense shear rate. The forces during microfluidization lead to transformation in material structure and conformation which result in modifications in the material characteristics and can be a base for new application areas. Although microfluidization is commonly known with its effects on particle size reduction, this innovative technique is also highly successful for formation of emulsion-based systems. Recently, a few new application areas have emerged, such as nanoparticle formation and treatment of beverages. Despite increasing interest of using microfluidization in new areas, there is not a comprehensive review of these studies in the literature. Therefore, in this paper, these studies have been reviewed and discussed in three main categories: 1) emulsion-based systems, including dairy products and lab-created emulsions, 2) nanoparticles, and 3) beverages. Also, the processing factors that need to be taken into consideration are outlined in this review. Homogenizing milk with microfluidization significantly improved the physical properties of milk-derived products, especially textural properties. Microfluidization also provided better stability compared to conventional techniques and enabled production of new functional emulsions. Its liposome applications showed great potential to extend specific activities of substances. Microfluidization also improved bioavailability of food grade nanoparticles and helped eliminating cloudiness in beverages by significantly reducing particle size. • The success in dairy industry opened new sectors for microfluidization. • Microfluidization provides highly stable and functional emulsions. • Liposome applications have a potential to extend specific activities of substances. • It leads to the formation of food grade nanoparticles with improved bioavailability. • It eliminates cloudiness problem in beverages with decreased particle size. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (Hap) doped or embedded with silver has shown improved bactericidal properties, and its mechanical properties were greatly improved by doping or impregnating Hap with metals such as Magnesium or Zinc, or by impregnating Hap with metal oxides such as MgO, or ZnO. This work describes the preparation of Ag-ZnO-Hap nanocomposites with 4 different Ag-ZnO–Ca mole ratios. XRD, FTIR, SEM, and TEM analysis of all prepared materials identified Hap as the only crystalline phase present in all samples exhibiting a uniform rod-like morphology with particles in the 20–40 nm size range. Microwave Plasma-Atomic Emission Spectroscopy confirmed the presence of zinc and silver in all embedded Hap samples. The antibacterial activity was tested against two different strains; Escherichia coli (E. coli (MV10Nal), and Gram-negative Aggregatibacter actinomycetemcomitans (A.a). The mechanical testing consisted of evaluating breaking force, work of fracture, and brittleness/ductility of Hap and Ag/ZnO/Hap composites. Our study clearly shows that reinforcing Hap with silver and zinc oxide yields superior bactericidal and mechanical properties. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Ophthalmology is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Amide I and Amide III vibrational modes are frequently used to study protein secondary structure with Fourier transform infrared (FT-IR) spectroscopy. However, for protein mixtures, neither the sole Amide I nor Amide III region provides sufficient information for structural quantitation because of overlapping peaks, especially in the Amide I region. Here, an improved quantitative approach is proposed to estimate secondary structure of protein systems using resolution enhancement and curve-fitting data processing techniques on a gluten model system to investigate structure-function relationships. Twelve different scenarios were prepared to assign bands in the Amide I region. Frequency ranges of 1660–1640 cm−1 and 1665–1660 cm−1 were found to highly contribute to variability in secondary structure contents of samples. Utilization of the Amide III region as a conducive tool to assign bands in the Amide I region led to a better differentiation of some secondary structural motifs and a more accurate quantitation of protein secondary structure. The study presents an understanding of FT-IR data analysis for a quick technique to assess secondary structures of protein mixtures. • An improved quantitative approach was developed for secondary structure contents. • Six different scenarios were prepared to assign bands in the Amide I region. • Amide III region was utilized as a conducive tool to assign bands in the Amide I region. • The method was applied to a model system containing wheat gluten. • This method led to better differentiation of some secondary structural motifs. [ABSTRACT FROM AUTHOR]

Biohydrogen production from dairy wastewater with subsequent biogas purification by hollow fiber membrane module was investigated in this study. The purified and not purified (raw) biohydrogen were used as fuel in polymer electrolyte membrane (PEM) fuel cell. Furthermore, the effect of CO 2 on the performance of PEM fuel cell was evaluated considering cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and polarization curves. The maximum H 2 production rate was 0.015 mmol H 2 /mol glucose and the biohydrogen concentration in biogas was ranged 33%–60% (v/v). CO 2 /H 2 selectivity decreased with increasing pressure and maximum selectivity was obtained as 4.4 at feed pressure of 1.5 bar. The electrochemical active surface (EASA) areas were decreased with increasing CO 2 ratio. The maximum power densities were 0.2, 0.08 and 0.045 W cm−2 for 100%, 80% and 60% (v/v) H 2 , respectively. The results indicated that integrated PEM fuel cell/biogas purification system can be used as a potential clean energy sources during acidogenic biohydrogen production from dairy wastewater. Image 1 • Dairy wastewater is a suitable substrate for acidogenic biohydrogen production. • Biohydrogen purification and PEM fuel cell was integrated to acidogenic system. • Silicone hollow-fiber membrane has higher CO 2 permeance over H 2. • The purified and not purified biohydrogen were used as fuel in PEM fuel cell. • CO 2 is blocking the active platinum sites thus fuel cell performance reduces. [ABSTRACT FROM AUTHOR]

Abstract This study presents a potential application for adding value to corn gluten meal, which is often used as animal feed and underutilized in food industry. This study is aimed to improve water holding ability of zein-rich by product corn gluten and investigate possibility of using it as an emulsifier. The potential use of microfluidization (500–1250 bar and 25 °C) and pH shifting (to pH6, 8, and 10) as a modification process for corn gluten meal and their effects on emulsifying properties were investigated. The formulations used for CGM(g):corn oil (mL) mixtures were 5:15, 5:30, 5:50, 10:15, 10:30, 10:50, 15:15, 15:30, and 15:50. Microfluidization and pH modification decreased the particle size of emulsions, resulting in the formation of tissues and micropores, and a consequent increase in surface area and water-holding capacity. pH shifting in dispersions around neutrality (pH6 and pH8) provided improvements in emulsion properties; however, excessive shifting (pH10) caused protein denaturation. Herschel-Bulkley model was well-fitted to explain flow behaviors. Flow and viscoelastic measurements showed that all formulations exhibited shear thinning and elastic gel-like behavior. The sedimentation rate, measured using LUMiSizer, was decreased by microfluidization and pH modifications. This study showed that these treatments can be used to convert an underutilized material into a valuable one in food industry. Highlights • Microfluidization opens up new industrial application possibilities for corn gluten. • Microfluidization improved water holding ability of zein-rich by product corn gluten. • Microfluidization provided homogenous structure by overcoming hydrophobic nature. • Microfluidization and pH shifting improved rheological properties of emulsions. • pH shifting around neutrality provided improvements in emulsion properties. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) have become prevalent in various environmental compartments, including air, water, and soil, attracting attention as significant pollutant parameters. This study investigated the prevalence of MP pollution in surface sediments along Istanbul's Marmara Sea, encompassing the megacity and the Bosphorus. A comprehensive sampling approach was employed, covering 43 stations across four seasons and depths ranging from 5 to 70 m. The objective was to assess the impact of terrestrial, social, and industrial activities on MPs. The average concentrations varied per season, with fall, winter, spring, and summer values recorded as 2000 ± 4100, 1600 ± 3900, 4300 ± 12,000, and 9500 ± 20,300 particles/kg-DW. The study identified river stations in the Golden Horn and sea discharge locations as hotspots for high concentrations. Notably, the dominant shape shifted from fibers in fall, winter, and spring to fragments during summer, coinciding with mucilage occurrences. The study identified 11 different polymers, with polyethylene (44 %) and polypropylene (31 %) being the most common. [Display omitted] • MPs presence in Istanbul coast sediments of Marmara Sea was investigated. • River, sea discharge, and pier stations had highest MPs in Marmara Sea sediments. • PE and PP comprised 75 % of MPs; fibers dominant in fall, winter, spring, while fragments prevail in summer. • The Marmara Sea in Istanbul serves as a hotspot for MPs, demanding targeted actions. [ABSTRACT FROM AUTHOR]

Background The availability and movement of water inside the food materials play essential roles for food stability by affecting their physical and chemical properties, and microbiological activity. Understanding the moisture sorption behavior is a necessary step to control food properties. Food processing unit operations like drying and cooking influence the behavior of starch since such systems trigger swelling or shrinkage as a result of moisture sorption or desorption mechanisms. Also, these processes alter many aspects of starch-containing foods such as acceptability, nutritional value, quality, and shelf-life. Scope and approach Therefore, understanding the water transport in starchy foods and the changes occurring in functional properties of starch has a great importance to describe and model their sorption and drying behavior. First, the primary mechanisms occurring during water transport such as moisture sorption, swelling, gelatinization, and glass transition are discussed using experimental results presented in the literature. Additionally, the hybrid mixture theory (HMT) and its potential for predicting transport mechanisms in starchy foods is discussed. Key findings and conclusions In addition to experimental considerations, the mathematical modeling provides complementary information to predict the heat and fluid transfer. The hybrid mixture theory based multiscale models are able to describe the physico-chemical changes and general transport mechanisms occurring within a porous food matrix. This theory can also be used to predict the quality changes in food products during processing. [ABSTRACT FROM AUTHOR]

This study presents the potential of microfluidization as a value adding process to corn gluten meal (CGM), which is often used as animal feed and is underutilized in food industry. In this study, we aimed to improve water holding ability of corn gluten and to investigate possibility of using this zein-rich byproduct as the main ingredient in gluten-free bread formulations. For this reason, microfluidization as a milling process for CGM, and its effects on rheological and textural properties of gluten-free bread formulations were investigated. In addition, the effects of pH modification and hydrocolloids were analyzed. Microfluidization led to a higher surface area by disintegrating the large CGM molecules, and the structure became compatible to be used in gluten-free bread formulations by overcoming hydrophobic nature. However, structural deformations were detected with pH modifications. The linear viscoelastic region of dough was observed at strains lower than 0.5%. For all formulations, elastic moduli (G') were higher than viscous moduli (G") indicating solid-like behavior. The addition of HPMC and guar resulted in higher moduli values. Microfluidization and pH modifications provided brighter color by revealing lutein and zeaxanthin due to decreased particle size. Texture profile showed that microfluidization and hydrocolloids decreased hardness, increased springiness and cohesiveness, which are desired characteristics for bread. Lastly, the addition of hydrocolloids led to an increase in specific volume by providing gas retention within the structure. HPMC provided 1.23–1.62 times bigger samples than control samples while it was only 1.02–1.12 times bigger for samples with guar according to specific volume analysis. [ABSTRACT FROM AUTHOR]

Performance of cathode materials in microbial fuel cell (MFC) from dairy wastewater has been investigated in laboratory tests. Both cyclic voltammogram experiments and MFC tests showed that Pt–Ni cathode much better than pure Pt cathode. MFC with platinum cathode had the maximum power density of 0.180 W m −2 while MFC with Pt:Ni (1:1) cathode produced the maximum power density of 0.637 W m −2 , even if the mass mixing ratio of Pt is lower in the alloy were used. The highest chemical oxygen demand (COD) removal efficiency was around 82–86% in both systems. The cyclic voltammogram (CV) analyses show that Pt:Ni (1:1) offers higher specific surface area than Pt alone does. X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) results showed that entire Pt:Ni (1:1) alloys can reduce the oxygen easily than pure platinum, even though less precious metal amount. The main outcome of this study is that Pt–Ni, may serve as a alternative catalyst in MFC applications. [ABSTRACT FROM AUTHOR]

Metal deficiencies in synthetic hydroxyapatite (Hap), is one factor among others behind its poor mechanical reliability. Hence, compensating these deficiencies has been suggested as a possible way to improve these properties. Several studies have shown that the incorporation of metals or metal oxides appear to increase the fracture toughness and lower the brittleness of synthetic Hap. In this study, we examined the resultant effect of two different methods of incorporating metals into the Hap structure on its mechanical properties. The first method consisted of incorporating metals by replacing some calcium in the Hap structure via substitution. The second method consisted of modifying Hap by preparing (metal oxide)/Hap composites. Thus Nano powders of pure Hap, substituted Hap (Ca 10-x M x (PO 4) 6 (OH) 2), and (MO) x /Hap composites (M = Mg, Zn) with x = 0.0, 0.1, and 0.3 were prepared by a simple low temperature technique. The (ZnO) x /Hap nanocomposites were prepared by precipitating Zinc oxide nanoparticles in a nano Hap slurry, while the (MgO) x /Hap composites were prepared by precipitating Hap nanoparticles in a diluted nano MgO slurry. XRD, FTIR, and SEM analysis of all prepared materials identified Hap as the only crystalline phase present, exhibiting a uniform morphology with particles in the 40–100 nm size range. EDAX analysis clearly shows the presence of Ca, P, and O in pure hydroxyapatite, Ca, P, O, Mg and Zn in both substituted Hap and (MO) x /Hap composites. The mechanical testing consisted of evaluating Breaking force, work of fracture, and brittleness/ductility of Hap, substituted Hap, and (MO) x /Hap composites. Our study clearly shows that the mechanical properties of Hap are much more improved by modifying Hap with metal oxides than by calcium substitution for the same quantity and type of incorporated metal. Optimum mechanical strength was obtained for the (MO) x /Hap composites with a 0.1:1.0 MO:Hap mole ratio (M = Mg, Zn). [ABSTRACT FROM AUTHOR]

Aim To compare once- versus twice-daily insulin detemir added on OADS therapy in insulin-naive type 2 diabetes patients in terms of efficacy and safety. Methods An open-label study performed at a single center, comprised a randomized, crossover 24 week with insulin-naive type 2 diabetes patients. Insulin detemir was initiated with mean 0.12 U/kg in all patients (Group I once-daily, Group II twice-daily) and titrated for 24 week. Results A total of 50 patients completed the study (Group I n:25, Group II n:25). With use of once- and twice-daily insulin, HbA1c values were decreased by 1.8% (±2.0) and 1.5% (±1.4) within the first 12 weeks (p < 0.01), whereas increased by 0.21% (±0.7) and 0.14% (±0.8) in the second 12 weeks (p > 0.05). The increases in the insulin doses were found as 0.22 U/kg and 0.35 U/kg with once- and twice-daily insulin use, respectively (p:0.04). Although minor hypoglycemic events were similar in both groups in the first 12 weeks, 2-fold increase was found in the patients shifting from once- to twice-daily dose. Within the first and second periods, the body weight of the patients was observed an increase of 0.4 and 1.6 kg with once-daily dose, whereas a decrease of 0.1 and 2.1 kg in the twice-daily dose, in the same period. Conclusion Once-daily use of insulin detemir up to 0.4 U/kg was found to have similar efficacy and safety as twice-daily use. Twice dose use of insulin did not provide a prominent glycemic control advantage on 1.5-fold higher use of insulin. [ABSTRACT FROM AUTHOR]

Abstract: A series of thin Pt films were deposited by dc magnetron sputtering directly on a commercial hydrophobic carbon paper substrate having a thin microporous Vulcan-XC72 layer or upon a thin Ti sublayer sputtered on the top of the microporous carbon film. The electrocatalytic properties of the sputtered Pt films toward the oxygen reduction reaction were investigated in 0.5M H2SO4 solution and in a hydrogen PEM fuel cell. The catalyst with ultralow Pt loading of 22μgcm−2 deposited on a 33Å thick Ti sublayer is robust, mechanically stable, possesses highly developed surface area and improved catalytic efficiency. Its performance as a MEA cathode in a single hydrogen PEM fuel cell (577mAcm−2 at 0.4V cell voltages and a maximum power of 0.954W) proved to be much superior compared to that of MEA with the same cathode Pt loading but without Ti sublayer (173mAcm−2 at 0.4V, 0.231W, respectively). [Copyright &y& Elsevier]

Cotton straws are one of the most produced agricultural wastes in Turkey and getting attention by not being consumed as animal feed or an industrial stock and having a huge potential in clean energy production. In this study, different pretreatment methods for the conversion of cotton straw to sugar then biohydrogen and biomethane production from cotton straw were examined. The energy potential of cotton straw in case of an evaluation of these biomass residues was also determined using fuel cell technology. Acid pretreatment provided the highest yield in biogas formation as well as sugar extraction from the raw sample. The highest biohydrogen and biomethane production were obtained as 33 mL H 2 /g VS and 83 mL CH 4 /g VS, respectively. Concomitantly, the maximum power peaks in PEM fuel cell studies were observed as 0.45 W/cm2 and 0.23 W/cm2 with current densities of 1.086 A/cm2 and 0.522 A/cm2 when the fuel cell was fed with pure H 2 and biogas, respectively. This suggested that acid pretreatment is more suitable for cotton straw management in sustainable and renewable ways and the results demonstrated that PEM fuel cell is a promising clean technology for energy generation from cotton straw. Image 1 • Cotton straws were extracted by using three different pretreatment methods. • Acid pretreatment was ~2 times effective than other methods in sugar extraction. • The highest bioH 2 and bioCH 4 production was 33 and 83 mL/g VS, respectively. • The biohydrogen was used as fuel in PEM fuel cells for clean energy generation. • The maximum power and current density in PEMFC were 23 W/cm2 and 0.522 A/cm2. [ABSTRACT FROM AUTHOR]

In the present work, new and efficient Cobalt–Titanium–Boride (Co–Ti–B) catalysts were developed for catalytic hydrolysis reaction of alkaline NaBH 4 solution. Hydrogen generation rate was measured using the ternary Co–Ti–B catalyst as a function of different Ti concentration, solution temperature, NaBH 4 concentration, and NaOH (a base-stabilizer) concentration. The performance of the system was analyzed from thermodynamic points of view and compared with the pristine Co–B catalyst. In addition to high catalytic efficiency, the catalyst must also comprise important features like high stability in severe conditions and should have high tolerance against deactivation. The highest hydrogen generation rate was obtained with 5% Ti/(Ti + Co) molar ratio, and for this catalyst the optimum fuel concentration was identified as 5 wt.% NaBH 4 with 5 wt.% NaOH. [ABSTRACT FROM AUTHOR]

The wildland-urban interface (WUI) is defined as a geographic area where human developments and flammable vegetation merge in a wildfire-prone environment. Losses due to wildfire have been rising in the past decade, attributed to changes in vegetation growth, fuel availability, and increased land developments in WUI. This paper studies the process of wildfire spread inside WUI communities. The fire spread rate within WUI communities is determined for nine wildfires that were ranked among the most destructive wildfires in North America. An improved quasi-empirical model that considers radiation and fire spotting as modes of fire spread inside a community is proposed. The new model is validated using the documented spread rates during the 2007 Witch and Guejito fires and the 2017 Tubbs fire. The proposed model is computationally efficient and can be used to quantify fire spread rate and the number of affected structures inside a community during a wildfire event. • Communities are being exposed to faster spreading wildfires in recent years. • A streamlined integrative urban fire spread model is proposed. • The proposed model is applied to two case studies in California. • The proposed model is capable of capturing fire progression in WUI communities when compared to real scenarios. [ABSTRACT FROM AUTHOR]

Electrochemical properties of porous nickel (Ni) foam, electrodeposited zinc (Zn) on Ni foam (Ni–Zn) and electrodeposited reduced graphene oxide (rGO) on Ni–Zn foam electrodes (Ni–Zn-rGO) in 6 M KOH electrolyte were investigated. Cyclic voltammetry (CV) and galvanostatic charge–discharge cycling (GCD) techniques were used to carry out the redox interactions, and cycling capacitive properties of the electrodes in KOH solution. Platinum (Pt) and gold (Au) foil were used as a counter electrode and the current collector in the electrochemical measurements, respectively. The specific capacitances of the electrodes were found from the GCD measurements as 155, 722 and 1820 F/g for Ni, Ni–Zn and Ni–Zn/rGO electrodes at the current density of 1 A/g, respectively. Scanning electron microscope (SEM) images of the three electrodes were also taken into account to associate all the electrochemical measurements. These results clearly show that specific capacitance values highly increased after the deposition of Zn and rGO to Ni electrode. Image 1 • Reinforced electrodes for supercapacitor applications. • Electrical deposition of zinc and graphene oxide. • Remarkable improvement of the energy and power densities. • Low retention and high cycling performance [ABSTRACT FROM AUTHOR]