Fabrication and characterization of semiconductor based photo-catalysis for light-Driven water splitting

The straightforward, low-priced and hence extensive conversion of sun light utilizing photocatalysis in a water splitting process is the main source to provide a clean and renwable hydrogen supply. Principally, photocatalysts are semiconductor materials with a suitable band gap that can absorb incident photons to produce photogeneated charges which consequently initiate the water splitting reaction to generate oxygen and hydrogen. The process itself is typically influenced by the material properties of the semiconductor (band gap, redox potentials and crystallinity) thus, altering the band structure of the semiconductor would help build up a photocatalyst that is appropriate for susbtaintial hydrogen generation. This thesis exemplifies a detailed study of high performance yet affordable photo-electrodes for solar-driven hydrogen production using Titanium (II) oxide (TiO2). TiO2 is considered to be a favorable photocatalyst that can be used as a photoanode in the photoelectrochemical cell due to its unique properties. In particular it\u27s high physical and chemical stability, high oxidizing power of the photogenerated holes, low-cost and non-toxicity. However, TiO2 is ideal for water splitting only under ultraviolet (UV) light due to its band gap that reaches 3.2 eV which makes its photocatalytic activity only restricted to the UV range that comprises only about 3% of the whole solar spectrum. In this study, two titania based photoanode systems were investigated in an effort to optimize the trade-off between the low external bias needed (electrical energy input) and the high photocurrent spectral response (H2 output). In the first part, Na-modified TiO2 nanostructured electrodes were studied. Varying the Na content showed a noticeable impact on the optical as well as the photoelectrochemical characteristics. The morphological characterization affirmed the presence of a discontinuous layer adsorbed over the surface of the TiO2 nanotubes where the tublar structure is kept preserved after treatment. Chemical analysis revealed no significant change in the structural properties of TiO2 upon modification which proves that the alkali ions were just dispersed within the TiO2 network. Optical properties illustrate the inclusion of conduction band tail states attributed to the disordered structure where the absorption edge is slightly shifted towards higher wavelength regions. The modified electrodes maintained nearly 81 % enhancement in the photoconductivity (0.9928 mA cm-2) in comparison with that of bare TiO2 (0.1821 mA cm-2) under AM 1.5G illumination (100 mW cm-2, 0.05 M Ba (OH) 2). Also, improved carriers\u27 separation and mobility has been accomplished which was asserted by the electrochemical impedance spectroscopy that revealed less charge transfer resistance as well as space charge capacitance for the surface modified electrodes. Further, the Mott-Schottky analysis affirmed the observed Voc enhancement by demonstrating a negative shift in the flat band potential for all the Na+-modified electrodes with respect to that of the pristine TiO2 implying less band bending requirements. Finally, DFT calculations were implemented to add further details on the electronic structure of the disordered titania confirming the empirical findings obtained upon surface modification. In the second part of this work, hybrid PEDOT/TiO2 photoelectrodes were analyzed. The development of such nanocomposites was accomplished by controlled electrochemical anodization of Ti foil, followed by a simple and fast spin coating of PEDOT. The heterojunctions maintained superior optical sensitivity where the absorption band edge reaches nearly 694 nm with respect to that of the unsensitized (TiO2 382 nm). This clearly indicates the ability to promote water splitting under visible irradiation. Likewise, superior photoelectrochemical performance concerning the photoconductivity, and the charge transfer kinetics were recognized mainly due to the fact that the highest occupied molecular orbit (HOMO) and lowest unoccupied molecular orbit (LUMO) of PEDOT are more negative than the conduction band (CB) and the valence band (VB) of TiO2. This in return, not only narrows down the band gap but also facilitates the separation of photo-induced charges and accordingly improves the photocatalytic activity

Editorial: Plant Derived Products to Combat Bacterial, Fungal and Parasitic Pathogens

Editorial, abstract not availabl

Avaliação da sorção de lindano sobre carvão ativado derivado de palha de arroz e biomassa fúngica de Phanerochaete chrysosporium

Rice straw was used for preparation of activated carbon using chemical activation by impregnation with concentrated H3 PO4 followed by pyrolysis at 500 º C for 2h. Physicochemical properties were investigated by several procedures; elemental analysis, scan electron microscope and porosity characteristics. Batch experimental mode was applied for adsorption and biosorption studies. A matrix effect analysis is applied to correlate the lindane adsorption or biosorption capacity to the agitation time, initial levels of lindane and carbon dose or biosorbent concentration. The Scanning Electron Microscope images equipped with Energy-dispersive X-ray reflect the enhancement of thermo-chemical activation by H3 PO4 in increasing the porosity of AC. Sorption behavior of Lindane by Activated Carbon (AC) and Phanerochaete chrysosporium, respectively have been studied to compare the obtained results in order to consider cost effective method for agriculture wastewater treatment. The adsorption capacity and distribution coefficients were determined for the adsorption system as a function of sorbate concentration. Under the studied concentrations, the adsorption of lindane by AC and its biosorption by Phanerochaete chrysosporium match to Langmuir as well as Freundlich isotherms. Afterword, adsorption and biosorption behavior was assessed by calculation of constants for each isothermal model. Finally, Biosorption of Lindane by Phanerochaete chrysosporium showed higher and faster removal compared with AC derived from rice straw.Utilizou-se palha de arroz para a preparação de carvão ativado por ativação química por impregnação com H3PO4 concentrado seguido de pirólise a 500 ºC por 2h. As propriedades físico-químicas foram investigadas por vários procedimentos; Análise elementar, microscopia eletrônica de varredura e características de porosidade. O modo experimental em lote foi aplicado para estudos de adsorção e biossorção. Uma análise de efeito de matriz é aplicada para correlacionar a capacidade de adsorção ou de biossorção de lindano com o tempo de agitação, os níveis iniciais de lindano e dose de carbono ou concentração de biossorvente. As imagens do microscópio eletrônico de varredura, equipadas com raios X de dispersão de energia, refletem o aumento da ativação termoquímica por H3PO4 no aumento da porosidade de AC. O comportamento de sorção do Lindano por Carvão Ativado (AC) e Phanerochaete chrysosporium, respectivamente, tem sido estudado para comparar os resultados obtidos, a fim de considerar o método de custo efetivo para o tratamento de águas residuais da agricultura. A capacidade de adsorção e os coeficientes de distribuição foram determinados para o sistema de adsorção em função da concentração de sorbato. Sob as concentrações estudadas, a adsorção de lindano por AC e sua biossorção por Phanerochaete chrysosporium combinam-se a Langmuir assim como isotermas de Freundlich. O comportamento de adsorção e biossorção foi avaliado por cálculo de constantes para cada modelo isotérmico. Finalmente, a Biossorção de Lindano por Phanerochaete chrysosporium mostrou maior e mais rápida remoção comparada com AC derivada de palha de arroz

Potential of wild plant Artemisia judaica L. as sustainable source of antioxidant and antimicrobial compounds

Artemisia judaica L. (Shih Balady, family Asteraceae), is a medicinal plant that grows in the desert, commonly used as tea by population in Egypt Sinai and of Saudi Arabia. The present study aims to evaluate antimicrobial and antioxidant activities of aerial parts of A. judaica collected from the inland desert (Wadi Hagoul) of Egypt. Total phenolics, tannins, alkaloids, flavonoids, and saponins were measured in the plant of interest. According to the reduction of DPPH the anti-oxidant activity was measured. Different extracts of A. judaica were screened for their antimicrobial activity against nine pathogenic microorganisms using filter paper disc assay. The secondary metabolites of A. judaica were examined and proved that it was rich in tannins and phenolics (13.29 and 7.62 mg/g dw). The IC50 values of A. judaica extract was 1.78 mg.ml-1 compared to standard catechol (0.15 mg.ml-1). In the present study, the extracts of A.  judaica showed unusual activity depending on the type of bacteria and fungi. Also, ethyl acetate and methyl alcohol extracts showed considerable broad spectrum (77.78%, each) against both bacteria and fungi, followed by acetone, then methylene chloride and petroleum ether extracts. This study showed that A. judaica extracts could be used as antimicrobial substances in pharmaceutical and food preservation systems

Knowledge of Palliative Care among Bachelors Nursing Students

Background: Palliative care clinical nurse specialists play an important role in specialist palliative care. They spend time with patients and their families, helping them come to terms with an array of complex emotional and practical problems, facilitating communication, giving information and advice about treatments and also offering expertise in controlling pain and other distressing symptoms. Aim of the study: The purpose of this study was to assess the PC knowledge using PCQN of  BSN students in Arab American University/ Jenin, Palestine.Subjects and methods: Descriptive, cross sectional study was used for conducting the study, A convenience sample 198 nursing students were included  from the two respective nursing levels third year and fourth year. Data collected through; demographic characteristic and PC knowledge. The PCQN  scale was used as the tool to assess the PC knowledge level. Results:  The total percentage rate on the PCQN was 40.58% (SD=13.89011). There is no statistically significant difference at (p < 0.05) between PC knowledge and gender, academic level, personal or professional experience with palliative care, and course of palliative care (0.377, 0.896, 0.741, and 0.829) respectively. Highly statistically significant relation according age (p˃0.000).Conclusion: Clinical Relevance: third and fourth level BSN students had lack adequate information on palliative care, and did not meet the AACN expectation of a generalist registered nurse. Keywords: Knowledge, Nursing students, Palliative car

Medical system based on thermal optical system and neural network

Military personnel in the training or operational phases always need constant medical examination, but the presence of efficient medical care is difficult to implement in real-time for such cases. A wireless system for thermal tracking of soldiers was proposed, as well as tracking their vital signs in real time. Thermal cameras are used with an optical system designed to increase the accuracy of the thermal images captured as the change in the electro-cardiogram, heart rate, and temperature measurements are measured using a specially designed circuit. The results from both the thermal system and the biometric system are combined and sent to a computer for analysis using a model prepared with neural network technology. The proposed system was tested, and a database was created for 127 males and 110 females during training and rest times. The neural network model achieved a response time of 85 seconds until the release of the final analysis, and the accuracy of the proposed tracking system is 96%. The main contribution of this paper is the design of an integrated portable system for rapid, in-field, real-time military medical diagnostics