Modification of bacterial cell membrane to accelerate decolorization of textile wastewater effluent using microbial fuel cells: role of gamma radiation

The aim of the present work was to increase bacterial adhesion on anode via inducing membrane modifications to enhance textile wastewater treatment in Microbial Fuel Cell (MFC). Real textile wastewater was used in mediator-less MFCs for bacterial enrichment. The enriched bacteria were pre-treated by exposure to 1 KGy gamma radiation and were tested in MFC setup. Bacterial cell membrane permeability and cell membrane charges were measured using noninvasive dielectric spectroscopy measurements. The results show that pre-treatment using gamma radiation resulted in biofilm formation and increased cell permeability and exopolysaccharide production; this was reflected in both MFC performance (average voltage 554.67 mV) and decolorization (96.42%) as compared to 392.77 mV and 60.76% decolorization for non-treated cells. At the end of MFC operation, cytotoxicity test was performed for treated wastewater using a dermal cell line, the results obtained show a decrease in toxicity from 24.8 to 0 (v/v%) when cells were exposed to gamma radiation. Fourier-transform infrared (FTIR) spectroscopy showed an increase in exopolysaccharides in bacterial consortium exposed to increasing doses of gamma radiation suggesting that gamma radiation increased exopolysaccharide production, providing transient media for electron transfer and contributing to accelerating MFC performance. Modification of bacterial membrane prior to MFC operation can be considered highly effective as a pre-treatment tool that accelerates MFC performance

Carbonate alteration of ophiolitic rocks in the Arabian–Nubian Shield of Egypt: sources and compositions of the carbonating fluid and implications for the formation of Au deposits

Ultramafic portions of ophiolitic fragments in the Arabian–Nubian Shield (ANS) show pervasive carbonate alteration forming various degrees of carbonated serpentinites and listvenitic rocks. Notwithstanding the extent of the alteration, little is known about the processes that caused it, the source of the CO2 or the conditions of alteration. This study investigates the mineralogy, stable (O, C) and radiogenic (Sr) isotope composition, and geochemistry of suites of variably carbonate altered ultramafics from the Meatiq area of the Central Eastern Desert (CED) of Egypt. The samples investigated include least-altered lizardite (Lz) serpentinites, antigorite (Atg) serpentinites and listvenitic rocks with associated carbonate and quartz veins. The C, O and Sr isotopes of the vein samples cluster between −8.1‰ and −6.8‰ for δ13C, +6.4‰ and +10.5‰ for δ18O, and 87Sr/86Sr of 0.7028–0.70344, and plot within the depleted mantle compositional field. The serpentinites isotopic compositions plot on a mixing trend between the depleted-mantle and sedimentary carbonate fields. The carbonate veins contain abundant carbonic (CO2±CH4±N2) and aqueous-carbonic (H2O-NaCl-CO2±CH4±N2) low salinity fluid, with trapping conditions of 270–300°C and 0.7–1.1 kbar. The serpentinites are enriched in Au, As, S and other fluid-mobile elements relative to primitive and depleted mantle. The extensively carbonated Atg-serpentinites contain significantly lower concentrations of these elements than the Lz-serpentinites suggesting that they were depleted during carbonate alteration. Fluid inclusion and stable isotope compositions of Au deposits in the CED are similar to those from the carbonate veins investigated in the study and we suggest that carbonation of ANS ophiolitic rocks due to influx of mantle-derived CO2-bearing fluids caused break down of Au-bearing minerals such as pentlandite, releasing Au and S to the hydrothermal fluids that later formed the Au-deposits. This is the first time that gold has been observed to be remobilized from rocks during the lizardite–antigorite transition

Genetic polymorphism in melatonin receptor 1A and arylalkylamine N-acetyltransferase and its impact on seasonal reproduction in Egyptian sheep breeds

This study was carried out to detect polymorphisms in the melatonin receptor 1A (MTNR1A) and arylalkylamine N-acetyltransferase (AA-NAT) genes and their association with reproductive traits. Blood samples of 126 animals from three Egyptian sheep breeds were collected. DNA was extracted and subjected to PCR restriction fragment length polymorphism (RFLP) analysis using the RsaI and SmaI enzymes. Two alleles (C and T) and three genotypes (CC, CT and TT) for MTNR1A and for AA-NAT (A and G; GG, GA and AA) were detected. The alleles C and A and the genotypes CT and GA showed the highest frequencies for the MTNR1A and AA-NAT genes, respectively. Association analysis of the MTNR1A single nucleotide polymorphism (SNP) with ewe reproductive traits revealed significant associations in the Ossimi and Rahmani breeds with age at first lambing, and the C allele seemed to be the favorable allele. The results for the AA-NAT SNP demonstrated significant correlations in Ossimi with age at first lambing and litter size and in Rahmani with lambing interval; the G allele seemed to be the desirable allele. In the first conception season, ewes carrying CT exhibited a significantly lower age of first lambing in the unfavorable season. Additionally, GG ewes exhibited a significantly lower age of first lambing in the early favorable season, followed by the unfavorable season. To the best of our knowledge, this is the first study of these associations in Egyptian sheep breeds. In conclusion, the polymorphisms revealed in this study could be used as genetic markers to improve reproductive efficiency during the unfavorable season, and the obtained desirable genotypes could be considered in new genetic selection schemes.</p

An investigation into the effect of rate of stirring of bath electrolyte on the properties of electrodeposited CdTe thin film semiconductors

Electrodeposition (ED) has been recognized as a low cost and scalable technique available for fabrication of CdS/CdTe solar cells. Photovoltaic activity of these electrodeposited semiconductor materials drastically depends on the ED growth parameters namely; electrodeposition potential, concentrations and ratios of concentrations of precursors used to prepare the bath electrolyte, pH of the electrolyte, deposition temperature and rate of stirring of the electrolyte. In order to grow thin films with good photovoltaic properties, it is essential to maintain these variables at their optimum ranges of values during electrodepositions. Hence, this study was conducted to investigate the dependence of the properties of electrodeposited CdTe thin film material on the rate of stirring of the bath electrolyte. The CdTe material was grown on glass/FTO (23 cm2) and glass/FTO/CdS (23 cm2) surfaces in bath electrolytes containing 1.0 mol/L CdSO4 and 1.0 mmol/L TeO2 solutions at different rates of stirring within the range of 0-350 rpm while keeping the values of pH of the electrolyte, deposition temperature and cathodic deposition potential with respect to the saturated calomel electrode at 2.3, 65 °C and 650 mV respectively. After the heat treatment at 400 °C in air atmosphere, the deposited samples with a good visual appearance were selected and evaluated based on their morphological, elemental, structural, optical and electrical properties in order to identify the optimum range of rate of stirring for electrodeposition of CdTe thin film semiconductors. Results revealed that, rates of stirring in the range of 60-85 rpm in a 100 mL volume of electrolyte containing the substrate and the counter electrodes in the center of the bath with a separation of 2.0 cm between them can electrodeposit CdTe layers exhibiting required levels of morphological, structural, optical and electrical properties on both glass/FTO and glass/FTO/CdS surfaces

Modification of bacterial cell membrane to accelerate decolorization of textile wastewater effluent using microbial fuel cells: role of gamma radiation, salinity and endogenous biosurfactant induction

A combined approach was investigated to accelerate Microbial Fuel Cell (MFC) performance and textile wastewater decolorization through modifying bacterial membrane. The aim was to increase both bacterial adhesion on anode and electron mediator release. Ten Gram-positive exoelectrogenic bacteria were isolated from the anodic biofilm after decolorization of real textile waste water in mediator-less MFC. The isolates were identified and characterized, to understand the nature of the bacteria involved. According to the battery of tests performed, three factors gamma radiation, salinity and induction of endogenous biosurfactant were involved membrane modification. Dielectric measurement, a non-invasive technique, was used to measure the cell membrane permeability and cell surface charge. Plackett-Burman experimental design was carried out to determine the key contributor among the three studied factors. Exposing the cells to 1 KGy gamma radiation led to 7.84- and 1.71- fold increase in total surface-charge and cell-permeability, respectively. Scanning Electron Microscope (SEM) images and surface-bound protein concentrations for the samples indicated that biofilm formation increased under the same conditions. These results have been reflected on the power density profiles and decolorization of textile wastewater. Modification of bacterial membrane prior to MFC operation can be considered highly effective as a pre-treatment tool that accelerates MFC performance

Oval Domes: History, Geometry and Mechanics

An oval dome may be defined as a dome whose plan or profile (or both) has an oval form. The word Aoval@ comes from the latin Aovum@, egg. Then, an oval dome has an egg-shaped geometry. The first buildings with oval plans were built without a predetermined form, just trying to close an space in the most economical form. Eventually, the geometry was defined by using arcs of circle with common tangents in the points of change of curvature. Later the oval acquired a more regular form with two axis of symmetry. Therefore, an “oval” may be defined as an egg-shaped form, doubly symmetric, constructed with arcs of circle; an oval needs a minimum of four centres, but it is possible also to build polycentric ovals. The above definition corresponds with the origin and the use of oval forms in building and may be applied without problem until, say, the XVIIIth century. Since then, the teaching of conics in the elementary courses of geometry made the cultivated people to define the oval as an approximation to the ellipse, an “imperfect ellipse”: an oval was, then, a curve formed with arcs of circles which tries to approximate to the ellipse of the same axes. As we shall see, the ellipse has very rarely been used in building. Finally, in modern geometrical textbooks an oval is defined as a smooth closed convex curve, a more general definition which embraces the two previous, but which is of no particular use in the study of the employment of oval forms in building. The present paper contains the following parts: 1) an outline the origin and application of the oval in historical architecture; 2) a discussion of the spatial geometry of oval domes, i. e., the different methods employed to trace them; 3) a brief exposition of the mechanics of oval arches and domes; and 4) a final discussion of the role of Geometry in oval arch and dome design

First aid for obstetric haemorrhage: the pilot study of the non-pneumatic antishock garment in

Objective To compare the effect of non-pneumatic anti-shock garment (NASG) on blood loss from obstetric haemorrhage with standard management of obstetric haemorrhage. Design Observational study of consecutive obstetric haemorrhage cases before and after introduction of the NASG. Setting Four tertiary care maternity facilities in Egypt. Sample The sample consisted of women with obstetric haemorrhage and signs of shock and the entry criteria were: &gt;750 mL of blood loss and either pulse of &gt;100 beats per minute or systolic blood pressure of &lt;100 mmHg. A total of 158 women were in the preintervention group and 206 in the postintervention group. Methods All the women with haemorrhage meeting the eligibility criteria were treated according to the standard protocol for 4 months (May-August 2004); blood loss was measured and recorded. The NASG was then introduced, and all the women meeting the eligibility criteria were treated according to the standard haemorrhage protocol plus the NASG for 4 months (September-December 2004). Main outcome measures Measured blood loss collected in a closed-end, graduated, plastic, under buttocks collection drape. Results Median measured blood loss in the drape following study entry was 50% lower in those treated with the NASG (250 versus 500 mL, P &lt; 0.001). There was also a non-statistically significant decrease in morbidity and mortality. Conclusions This is the first comparative study of the NASG with a standard obstetric haemorrhage treatment protocol. The NASG shows promise for management of obstetric haemorrhage, particularly in lower resource settings. Larger studies will be needed to determine if the NASG contributes to statistically significant decreases in morbidity and mortality

Effects of deposition time and post-deposition annealing on the physical and chemical properties of electrodeposited CdS thin films for solar cell application

CdS thin films were cathodically electrodeposited by means of a two-electrode deposition system for different durations. The films were characterised for their structural, optical, morphological and compositional properties using x-ray diffraction (XRD), spectrophotometry, scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) respectively. The results obtained show that the physical and chemical properties of these films are significantly influenced by the deposition time and post-deposition annealing. This influence manifests more in the as-deposited materials than in the annealed ones. XRD results show that the crystallite sizes of the different films are in the range (9.4 – 65.8) nm and (16.4 – 66.0) nm in the as-deposited and annealed forms respectively. Optical measurements show that the absorption coefficients are in the range (2.7×104 – 6.7×104) cm-1 and (4.3×104 – 7.2×104) cm-1 respectively for as-deposited and annealed films. The refractive index is in the range (2.40 – 2.60) for as-deposited films and come to the value of 2.37 after annealing. The extinction coefficient varies in the range (0.1 – 0.3) in asdeposited films and becomes 0.1 in annealed films. The estimated energy bandgap of the films is in the range (2.48 – 2.50) eV for as-deposited films and becomes 2.42 eV for all annealed films. EDX results show that all the films are S-rich in chemical composition with fairly uniform Cd/S ratio after annealing. The results show that annealing improves the qualities of the films and deposition time can be used to control the film thickness. Keywords: Electrodeposition; two-electrode system; CdS; annealing; deposition time; thin-film

Building WF16: construction of a PPNA pisé structure in Southern Jordan

The Pre-Pottery Neolithic A (PPNA) period in Southwest Asia is essential for our understanding of the transition to sedentary, agricultural communities. Developments in architecture are key to understanding this transition, but many aspects of PPNA architecture remain elusive, such as construction techniques, the selection of building materials, and the functional use of space. The primary aim of the research described within this contribution was to build a PPNA-like structure in order to answer questions about PPNA architecture in general, while specifically addressing issues raised by the excavation of structures at the site of WF16, Southern Jordan. The second aim was to display a ‘PPNA’ building to visitors in Wadi Faynan to enhance their understanding of the period. The experimental construction based on one of the WF16 structures showed that 1) required materials can be acquired locally; 2) a construction technique using mud layers as described in this paper was likely used; 3) flat, or very slightly dome-shaped, roofs are functional and can also be used as a solid working platform; 4) the WF16 small semi-subterranean buildings appear inappropriate for housing a nuclear family unit