Analytical study of a ground collector integrated with heat exchanger

This paper presents an analytical study of an underground water heater integrated with a heat exchanger. For quantitative assessment of the analytical results, numerical calculations have been made for a typical cold day, namely 21 December 1985 and the yearly data of 1984. The effects of heat exchanger length, water tank depth, etc. on the performance of the proposed system have been studied in detail. The tresults of the proposed system show that the system can be used to supply hot water in the winter months and cold water in the summer months, when the tank is placed at a depth of 0.30 m in the ground. This system will be very useful in areas where drinking water becomes hot in the summer.     

Distribution and biochemical composition of large and small seeds of soybean (Glycine max L.)

BACKGROUND: The position of soybean seeds on the stem axis brings about differences in seed filling during seed development, which contributes to different seed size and results in determining the quality of seeds for food usage. The quality differences between the large and small seeds are reported. RESULTS: The proportion of large seeds was higher at the apical portion while small seeds predominated at the basal portion of the soybean stem axis. The contents of lipids, starch, soluble sugars and soluble proteins were higher in large seeds as compared to those in small ones. The proportion of membrane lipid components, on a 10‐kernel basis, was higher in large seeds. The proportion of palmitate and oleate was also higher in large seeds. SDS‐PAGE analysis showed that glycinin (11S) proteins of 46 and 32 kDa were at higher concentrations, while 158 and 20 kDa were at lower concentration in large seeds in comparison to small seeds. Likewise, β‐conglycinins (7S) of 75, 62 and 46 kDa were higher in large seeds compared to small ones. CONCLUSION: Segregating the seeds of apical from the basal portion of soybean plant at harvest is expected to improve the germination, growth, yield and food‐processing aspects. Copyright © 2007 Society of Chemical Industry     

Intermediates in the reaction of fully reduced cytochrome c oxidase with dioxygen

The reduction of dioxygen to water by cytochrome c oxidase was monitored in the Soret region following photolysis of the fully reduced CO complex. Time-resolved optical absorption difference spectra collected between 373 and 521 nm were measured at delay times from 50 ns to 50 ms and analyzed using singular value decomposition and multiexponential fitting. Five processes were resolved with apparent lifetimes of 0.9 micros, 8 micros, 36 micros, 103 micros, and 1.2 ms. A mechanism is proposed and spectra of intermediates are extracted and compared to model spectra of the postulated intermediates. The model builds on an earlier mechanism that used data only from the visible region (Sucheta et al. (1997) Biochemistry 36, 554-565) and provides a more complete mechanism that fits results from both spectral regions. Intermediate 3, the ferrous-oxy complex (compound A) decays into a 607 nm species, generally referred to as P, which is converted to a 580 nm ferryl form (Fo) on a significantly faster time scale. The equilibrium constant between P and Fo is 1. We propose that the structure of P is a3(4+)=O CuB2+-OH- with an oxidizing equivalent residing on tyrosine 244, located close to the binuclear center. Upon conversion of P to Fo, cytochrome a donates an electron to the tyrosine radical, forming tyrosinate. Subsequently a proton is taken up by tyrosinate, forming F(I) [a3(4+)=O CuB2+-OH- a3+ CuA+]. This is followed by rapid electron transfer from CuA to cytochrome a to produce F(II) [a3(4+)=O CuB2+-OH- a2+ CuA2+].     

Reactive deposition of Y1Ba2Cu3O7 −x superconductor films by pulsed laser ablation from an unreacted mixture of Y2O3, BaCO3 and CuO

Superconducting thin films of Y₁Ba₂Cu₃ O_{7 −x} have been deposited on (100) Y-ZrO₂ substrates by pulsed excimer laser ablation from anunreacted mixture of Y₂O₃, BaCO₃ and CuO. The films deposited at substrate temperature of 680°C and oxygen partial pressure of 200 mtorr were found to be superconducting with zero resistive transition temperature of 89 K and critical current density of over 3 × 10⁵ A/cm² at 77 K. These results are compared with those obtained by laser ablation from a sintered superconducting pellet.     

Nonlinear optical absorption and switching properties of gold nanoparticle doped SiO2-TiO2 sol-gel films

The nonlinear optical absorption and switching properties of sol-gel derived of Au nanoparticle doped SiO2-TiO2 sol-gel films having different Au-surface plasmon absorption positions are reported in this paper. The Au nanoparticles are embedded in SiO2 and SiO2-TiO2 mixed glassy film matrices with different refractive index values. To study the nonlinear absorption properties, lasers with three different wavelengths are used. The optical switching behavior is studied by using the pump-probe technique with 532 nm as the excitation wavelength. Ground state conduction band, surface plasmon band, and the free carrier band are taken as three level model to explain theoretically the obtained RSA and SA behaviors.     

Studies of KVIC biogas system coupled with flat plate collector

a simple straightforward transient analysis of the Khadi Village Industrial Commission (KVIC) biogas plant coupled with a flat plate collector through a spiral/coil type heat exchanger is presented. To avoid night heast losses through the collectors, the plant is disassociated from the collectors during off-sunshine hours. The effects of various system parameters, viz. heat capacity of slurry, area of collectros, length of heat exchanger placed in slurry, flow rate, etc. on the variation of slurry temperature have been studied in detail. The results obtained from the proposed system have also been compared with the results of a conventional KVIC biogas plant. It is observed that the drop of slurry temperature in the harsh winter climatic condition can significantly be reduced by the present system, for higher production of biogas.     

Effect of CTAB coating on structural,magnetic and peroxidase mimic activity of ferric oxide nanoparticles

In the present work, pristine and cetyl trimethyl ammonium bromide (CTAB)-coated ferric oxide nanoparticles \((\hbox {CTAB@Fe}_{2}\hbox {O}_{3} \hbox { NPs})\) were synthesized and studied as enzyme mimics. The w/w ratio of \(\hbox {Fe}_{2}\hbox {O}_{3}\) to CTAB was varied as 1:1 and 1:2. Transmission electron microscopic analysis revealed that pristine NPs had an average size of 50 nm, whereas the presence of CTAB resulted in the formation of nanorods with length of 130 nm. BET studies confirmed enhancement of surface area on CTAB coating, which was maximum for w/w ratio 1:1. The synthesized pristine NPs and CTAB-coated NPs were evaluated for their peroxidase mimic activity using o-dianisidine dihydrochloride as substrate. Optimum pH, temperature, substrate and NPs concentration for the reaction were 1, \(25^{\circ }{\mathrm{C}}\), \(0.16~\hbox {mg}~\hbox {ml}^{-1}\) and \(1~\hbox {mg}~\hbox {ml}^{-1}\), respectively. Peroxidase mimic activity of \(\hbox {CTAB@Fe}_{2}\hbox {O}_{3}\hbox { NPs}\) (w/w 1:1) was higher than that of pristine NPs. However, further increase in CTAB coating (w/w 1:2) resulted in lowering of peroxidase mimic activity. Kinetic analysis was carried out at optimized conditions; maximum velocity (\(V_{\mathrm{max}})\) and Michaelis constant (\(K_{\mathrm{m}})\) value of \(\hbox {CTAB@Fe}_{2}\hbox {O}_{3}\hbox { NPs}\) at 1:1 w/w ratio were 7.69 mM and \(1.12~\upmu \hbox {mol}~\hbox {s}^{-1}\), respectively.     

Urinary Exosomes Identify Inflammatory Pathways in Vancomycin Associated Acute Kidney Injury

Background: Vancomycin is commonly used as a first line therapy for gram positive organisms such as methicillin resistant Staphylococcus aureus. Vancomycin-induced acute kidney injury (V-AKI) has been reported in up to 43% of patients, especially in those with higher targeted trough concentrations. The precise mechanism of injury in humans remains elusive, with recent evidence directed towards proximal tubule cell apoptosis. In this study, we investigated the protein contents of urinary exosomes in patients with V-AKI to further elucidate biomarkers of mechanisms of injury and potential responses. Methods: Urine samples from patients with V-AKI who were enrolled in the DIRECT study and matched healthy controls from the UAB-UCSD O’Brien Center Biorepository were included in the analysis. Exosomes were extracted using solvent exclusion principle and polyethylene glycol induced precipitation. Protein identity and quantification was determined by label-free liquid chromatography mass spectrometry (LC/MS). The mean peak serum creatinine was 3.7 ± 1.4 mg/dL and time to kidney injury was 4.0 ± 3.0 days. At discharge, 90% of patients demonstrated partial recovery; 33% experienced full recovery by day 28. Proteomic analyses on five V-AKI and 7 control samples revealed 2009 proteins in all samples and 251 proteins significantly associated with V-AKI (Pi-score > 1). The top discriminatory proteins were complement C3, complement C4, galectin-3-binding protein, fibrinogen, alpha-2 macroglobulin, immunoglobulin heavy constant mu and serotransferrin. Conclusion: Urinary exosomes reveal up-regulation of inflammatory proteins after nephrotoxic injury in V-AKI. Further studies are necessary in a large patient sample to confirm these findings for elucidation of pathophysiologic mechanisms and validation of potential injury biomarkers.