TMAO Suppresses Megalin Expression and Albumin Uptake in Human Proximal Tubular Cells Via PI3K and ERK Signaling

Trimethylamine-N-oxide (TMAO) is a uremic toxin, which has been associated with chronic kidney disease (CKD). Renal tubular epithelial cells play a central role in the pathophysiology of CKD. Megalin is an albumin-binding surface receptor on tubular epithelial cells, which is indispensable for urine protein reabsorption. To date, no studies have investigated the effect of TMAO on megalin expression and the functional properties of human tubular epithelial cells. The aim of this study was first to identify the functional effect of TMAO on human renal proximal tubular cells and second, to unravel the effects of TMAO on megalin-cubilin receptor expression. We found through global gene expression analysis that TMAO was associated with kidney disease. The microarray analysis also showed that megalin expression was suppressed by TMAO, which was also validated at the gene and protein level. High glucose and TMAO was shown to downregulate megalin expression and albumin uptake similarly. We also found that TMAO suppressed megalin expression via PI3K and ERK signaling. Furthermore, we showed that candesartan, dapagliflozin and enalaprilat counteracted the suppressive effect of TMAO on megalin expression. Our results may further help us unravel the role of TMAO in CKD development and to identify new therapeutic targets to counteract TMAOs effects.     

Exergy‐based performance analysis of packed‐bed solar air heaters

This paper presents an experimental investigation of the thermal performance of a solar air heater having its flow channel packed with Raschig rings. The packing improves the heat transfer from the plate to the air flow underneath. The dimensions of the heater are 0.9 m wide and 1.9 m long. The aluminium‐based absorber plate was coated with ordinary black paint. The characteristic diameter of the Raschig rings, made of black polyvinyl chloride (PVC) tube, is 50 mm and the depth of the packed‐bed in flow channel is 60 mm. Energy and exergy analyses were applied for evaluating the efficiency of the packed‐bed solar air heater. The rate of heat recovered from the packed‐bed solar air heater varied between 9.3 and 151.5 W m^?2, while the rate of thermal exergy recovered from the packed‐bed solar air heater varied between 0.04 and 8.77 W m^?2 during the charging period. The net energy efficiency varied from 2.05 to 33.78%, whereas the net exergy efficiency ranged from 0.01 to 2.16%. It was found that the average daily net energy and exergy efficiencies were 17.51 and 0.91%, respectively. The energy and exergy efficiencies of the packed‐bed solar air heater increased as the outlet temperature of heat transfer fluid increased. Copyright © 2004 John Wiley & Sons, Ltd.     

Extracorporeal shock wave lithotripsy in children

An experience with 103 children treated with extracorporeal shock wave lithotripsy (ESWL) is reviewed in this report. The success rate was 63%. The stone volume was of major importance for the result. There was a continuous decrease in success rate with increasing stone size. It was also shown that stone-free rates decreased with an increasing number of stones. Short-term complications were minor and hospitalization times were short. It is concluded that ESWL is a first-choice treatment in children with urinary calculi smaller than 200 mm2 in size.     

Effects of Ultrasonic Vibration on the Electroinitiated Copolymerisation of Styrene and Isoprene

Copolymerisation of styrene and isoprene by constant potential electrolysis in dichloromethane was achieved at different polymerisation potentials. Effect of ultrasonic vibration on the rate and the yield of polymerisation has been discussed. The composition of the copolymers was found to be affected by the vibration as well as the polymerisation potential (E_pol). At E_pol=+3.30 V we found that r₁=r₂ and mole percents of isoprene and styrene in copolymer were equal to each other. Equality was also observed on reacted monomer concentrations, at that potential, which can be called critical polymerisation potential. At E_pol values above or below the critical polymerisation potential none of the above-mentioned properties were equal. Monomer reactivity ratios were determined by the integrated Lewis-Mayo equation. Ultrasonic vibration as well as polymerisation potential was found to affect reactivity ratios.     

Electroinitiated and radiation-induced polymerisation of epoxycyclohexane

Liquid-state radiation-induced and electroinitiated polymerisations of epoxycyclohexane (ECH) have been investigated. The effect of temperature on the electroinitiated polymerisation rate was also studied. The decrease in monomer concentration during polymerisation was followed by gas chromatographic analysis of electrolysis solutions. The i.r. spectra of the polymers suggested polyether structure. N.m.r. spectra of products indicate that the polymerisation of ECH propagates through the opening of the epoxy rings. Poly(epoxycyclohexane) obtained by both methods are amorphous according to X-ray analyses.     

Mode I fracture toughness determination with straight notched disk bending method

A new method called the straight notched disk bending method is developed for mode I fracture toughness determination using rock cores. Disk specimens of andesite and marble having a single straight edge notch were subjected to three-point bending loads. Dimensionless stress intensity factor estimations and fracture toughness tests were conducted for different notch lengths, span lengths, thicknesses and diameters of the cylindrical rock specimens. Stress intensity factors were computed by three-dimensional finite element modeling and the results were presented for a wide range of specimen geometrical parameters. Results of experiments were compared to the results of well-known mode I fracture toughness testing methods. For specimens having thickness equal to the radius, mode I fracture toughness was lower and close to the results obtained by semi-circular bending method. When thickness was increased and doubled, mode I fracture toughness increased and approached to the value found by the suggested cracked chevron notched Brazilian disk method. Advantages of the new method included easy specimen preparation and testing procedure, stiffer specimen geometry, smaller fracture process zone, and flexibility of the specimen geometry for the investigation of the size effect behavior.     

Dyeing of Wool and Cotton with Extract of the Nettle (Urtica dioica L.) Leaves

The aim of the study is to investigate the optimum dyeing conditions for wool and cotton fabrics with the nettle (Urtica dioica L.) extract. For this purpose, the leaves of the nettle were extracted with distilled water by using Soxhlet apparatus. Wool and cotton fabrics were pretreated with artificial animal urine system (AAUS) including NH₃ (3%, v/v), CaC₂O₄ (3%, m/v), and urea (3%, m/v) before dyeing processes in order to improve the fastness properties of the dyed samples. The best dyeing conditions were evaluated in terms of color strength. The results reveal that the nettle leaves shall probably be an important raw material especially for dyeing of wool fibers.     

Characterization of products evolved from supercritical water gasification of xylose (principal sugar in hemicellulose)

The catalyst decomposition of xylose (the principal sugar in hemicellulose) was examined in supercritical water for temperature from 400 to 600°C. Experiments were performed in the absence and presence of three main types of catalysts [alkali catalysts (K₂CO₃ and KOH) and metal impregnated activated carbons (Ni/AC) and (Ru/AC)] with a reaction time of 1h. Gasification yield reaches maximum values by using K₂CO₃ and KOH at the highest temperature of 600°C. The highest H₂ yield and the highest CH₄ yield were obtained by using Ru/AC and Ni/AC, respectively. Acetic acid and 5-methyl furfural were determined as the main aqueous products and reached maximum value by using Ru/AC.     

Photovoltaic system assessment for a school building

The installation of photovoltaic panels (PVs) on the roof of residential and commercial buildings is getting widespread as these areas stand normally idle and can be used for another purpose without losing an inhabited space. Considering the solar potential of Turkey, a significant amount of electricity generation is possible using current PV technology. For this reason, a two-story detached school building located in ?zmir, Turkey was taken into consideration and monthly as well as annual coverage ratio of an on-grid PV system for its entire energy requirement (including heating, cooling and lighting) was investigated. The PVs were installed on the south face of the school building roof. A heat pump, with a typical coefficient of performance (COP) value of 2.5, was used for supplying required cooling and heating. The heating, cooling and lighting loads were determined on a monthly basis. The average monthly electrical energy generation of the mounted PVs was calculated using a written code in Energy Equation Solver (EES) software. As a result, the monthly as well as yearly electrical energy demand coverage ratio values for the school using the installed PVs were revealed. Since the school building has a large south faced roof, the installation of PVs is very suitable to meet the cumulative electrical energy need of the heat pump and the lighting load. For Case 1, 180 PVs, which supply the entire yearly demand (with a 110% coverage ratio), were taken into consideration, while for Case 2, 265 PVs, which cover 75% of the roof area, were evaluated. The results showed that between November and March, PV electrical energy generation is not sufficient to meet all energy need of the school for both cases. However, significant coverage ratio values were observed for the rest of the year. In a yearly basis, the PV generation exceeded the building demand by 62% for the Case 2. This conclusion points out that the school can meet its yearly electricity need with the considered PV system and can even have an additional financial profit by selling its surplus PV electricity to the grid. Economic and environmental payback time values as well as simple payback time value were also computed for both investigated cases. The results pointed out a simple payback time of 7.9 years for Case 1 and 7.6 years for Case 2. Energy payback time was determined as 5 years for both systems. The greenhouse gas payback time of 2.7 years and 5.9 years was encountered for coal based and natural gas based calculations.