Kristalna struktura i optička svojstva sustava Bi-Sb-Te-Se

The quaternary systems of Bi-Sb-Te-Se were synthesized by direct fusion technique. Thin films of these compounds were prepared by thermal evaporation under vacuum of 10−4 Pa. The structural properties of these compounds in powder and thin film forms were investigated by X-ray diffraction. The optical constants (absorption coefficient and band gap) of the thin films were determined by measurements of IR absorbance in the region 2.5 – 10 µm. Analysis of the optical absorption spectra revealed the existence of two direct energy gaps.Sintetizirali smo sustave Bi-Sb-Te-Se sa četiri sastavnice izravnom metodom staljivanja. Tanke slojeve tih spojeva pripremali smo isparavanjem u vakuumu (na 10−4 Pa). Primjenom rendgenske difrakcije odredili smo strukturna svojstva praha i tankih slojeva tih spojeva. Optičke konstante tankih slojeva (koeficijent apsorpcije i procijep med–u vrpcama) odredili smo mjerenjem apsorpcije u području 2.5 – 10 µm. Analiza optičkih apsorpcijskih spektara pokazuje dva izravna procijepa

Kristalna struktura i optička svojstva sustava Bi-Sb-Te-Se

The quaternary systems of Bi-Sb-Te-Se were synthesized by direct fusion technique. Thin films of these compounds were prepared by thermal evaporation under vacuum of 10−4 Pa. The structural properties of these compounds in powder and thin film forms were investigated by X-ray diffraction. The optical constants (absorption coefficient and band gap) of the thin films were determined by measurements of IR absorbance in the region 2.5 – 10 µm. Analysis of the optical absorption spectra revealed the existence of two direct energy gaps.Sintetizirali smo sustave Bi-Sb-Te-Se sa četiri sastavnice izravnom metodom staljivanja. Tanke slojeve tih spojeva pripremali smo isparavanjem u vakuumu (na 10−4 Pa). Primjenom rendgenske difrakcije odredili smo strukturna svojstva praha i tankih slojeva tih spojeva. Optičke konstante tankih slojeva (koeficijent apsorpcije i procijep med–u vrpcama) odredili smo mjerenjem apsorpcije u području 2.5 – 10 µm. Analiza optičkih apsorpcijskih spektara pokazuje dva izravna procijepa

Inexpensive organic dyes-sensitized zinc oxide nanoparticles photoanode for solar cells devices

Zinc oxide nanoparticles (ZnO NPs) were synthesized using a hydrothermal route. The prepared ZnO NPs were characterized by x-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), UV–vis spectroscopy, and photoluminescence (PL) spectroscopy. The XRD patterns confirmed the standard hexagonal wurtzite structure of ZnO NPs, and the calculated value of the average particle size was 23.34 nm. HR-TEM micrographs of ZnO NPs showed semispherical particle morphologies and their sizes lie between 10 and 40 nm. The estimated average size distribution of ZnO NPs was 21.35 6.01 nm. UV–vis spectrum of ZnO NPs revealed the highest absorption band at 360.5 nm, and the Eg was 3.70 0.01 eV. The PL spectrum emission was deconvoluted by eight peaks into two regions [near-ultraviolet (NUV) and visible that caused from the defects]. Two groups of dye-sensitized solar cells (DSSCs) thin film devices based on ZnO NPs were sensitized in different concentration solutions of 0.1, 0.32, and 0.5 mM of eosin B (EB) and eosin Y (EY) dyes. The sensitized DSSCs device with 0.32-mM dye of EY displayed higher efficiency and its performance parameters are much better among all other fabricated DSSCs devices. The short current density (Jsc) increased from 1.59 to 4:97 mA∕cm2 and the Voc enhanced from 0.36 to 0.46 V. The conversion efficiency from light to electricity showed a significant improvement from 0.29% to 0.94%. The transient open circuit photovoltage decay (TOCPVD) was measured to estimate the apparent electron lifetime or response time (τn) or the electron recombination rate (krec), using the double exponential function for first time to fit the experiment data of TOCPVD. The results revealed that the EY dye can be used as an efficient and an inexpensive dye for DSSCs.This research activity carried out between Gaza and Cairo-Egypt was financially supported by Qatar Charity IBHATH Project grant funded by the Gulf Cooperation Council for the Reconstruction of Gaza through the Islamic Development Bank.Zinc oxide nanoparticles (ZnO NPs) were synthesized using a hydrothermal route. The prepared ZnO NPs were characterized by x-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), UV–vis spectroscopy, and photoluminescence (PL) spectroscopy. The XRD patterns confirmed the standard hexagonal wurtzite structure of ZnO NPs, and the calculated value of the average particle size was 23.34 nm. HR-TEM micrographs of ZnO NPs showed semispherical particle morphologies and their sizes lie between 10 and 40 nm. The estimated average size distribution of ZnO NPs was 21.35 6.01 nm. UV–vis spectrum of ZnO NPs revealed the highest absorption band at 360.5 nm, and the Eg was 3.70 0.01 eV. The PL spectrum emission was deconvoluted by eight peaks into two regions [near-ultraviolet (NUV) and visible that caused from the defects]. Two groups of dye-sensitized solar cells (DSSCs) thin film devices based on ZnO NPs were sensitized in different concentration solutions of 0.1, 0.32, and 0.5 mM of eosin B (EB) and eosin Y (EY) dyes. The sensitized DSSCs device with 0.32-mM dye of EY displayed higher efficiency and its performance parameters are much better among all other fabricated DSSCs devices. The short current density (Jsc) increased from 1.59 to 4:97 mA∕cm2 and the Voc enhanced from 0.36 to 0.46 V. The conversion efficiency from light to electricity showed a significant improvement from 0.29% to 0.94%. The transient open circuit photovoltage decay (TOCPVD) was measured to estimate the apparent electron lifetime or response time (τn) or the electron recombination rate (krec), using the double exponential function for first time to fit the experiment data of TOCPVD. The results revealed that the EY dye can be used as an efficient and an inexpensive dye for DSSCs

Insight into Fucoidan-based PEGylated PLGA Nanoparticles Encapsulating Methyl Anthranilic Acid: In Vitro Evaluation and In Vivo Anti-inflammatory Study

A potential fucoidan-based PEGylated PLGA nanoparticles (NPs) offering a proper delivery of N-methyl anthranilic acid (MA, a model of hydrophobic anti-inflammatory drug) have been developed via the formation of fucoidan aqueous coating surrounding PEGylated PLGA NPs. The optimum formulation (FuP2) composed of fucoidan:m-PEG-PLGA (1:0.5 w/w) with particle size(365 ± 20.76 nm), zeta potential (-22.30 ± 2.56 mV), % entrapment efficiency (85.45 ± 7.41), drug loading (51.36 ± 4.75 µg/mg of NPs), % initial burst (47.91 ± 5.89), and % cumulative release (102.79 ± 6.89) has been further investigated for the anti-inflammatory in vivo study. This effect of FuP2 was assessed in rats’ carrageenan-induced acute inflammation model. The average weight of the paw edema was significantly lowered (p ≤ 0.05) by treatment with FuP2. Moreover, cyclooxygenase-2 and tumor necrosis factor-alpha immunostaining were decreased in FuP2 treated group compared to the other groups. The levels of prostaglandin E2, nitric oxide, and malondialdehyde were significantly reduced (p ≤ 0.05) in the FuP2-treated group. A significant reduction (p ≤ 0.05) in the expression of interleukins (IL-1b and IL-6) with an improvement of the histological findings of the paw tissues was observed in the FuP2-treated group. Thus, fucoidan-based PEGylated PLGA–MA NPs are a promising anti-inflammatory delivery system that can be applied for other similar drugs potentiating their pharmacological and pharmacokinetic properties

Influence of Metal Ion Doping of Zinc Oxide Photoanode on the Efficiency of Dye Sensitized Solar Cell

Doping zinc oxide nanoparticles (ZnO NPs) and doped with Niobium (Nb5+) and Aluminium (Al3+) ions were synthesized to use as a photoanode for the Dye Sensitized Solar Cells (DSSCs). The structural of the synthetized samples were examined via X-ray diffraction (XRD). The XRD patterns for all samples confirmed the hexagonal wurtzite structure. The DSSCs based on the undoped and doped ZnO NPs were fabricated and assembled. Scanning electron microscopic (SEM) images were measured for all fabricated devices. The doping Nb5+ and Al3+ ions influenced the performance of the DSSCs. ZnO NPs doped Nb5+ led to higher surface area and hence more dye loading and retard the recombination of charges, which enhanced the open circuit voltage

Debilitating floods in the Sahel are becoming frequent

Despite the long-lasting and widespread drought in the Sahel, flood events did punctuate in the past. The concern about floods remains dwarf on the international research and policy agenda compared to droughts. In this paper, we elucidate that floods in the Sahel are now becoming more frequent, widespread, and more devastating. We analyzed gridded daily rainfall data over the period 1981–2020, used photographs and satellite images to depict flood areas and threats, compiled and studied flood-related statistics over the past two decades, and supported the results with peer-reviewed literature. Our analysis revealed that the timing of the maximum daily rainfall occurs from the last week of July to mid-August in the Eastern Sahel, but from the last week of July to the end of August in the Western Sahel. In 2019 and 2020, flash and riverine floods took their toll in Sudan and elsewhere in the region in terms of the number of affected people, direct deaths, destroyed and damaged houses and croplands, contaminated water resources, and disease outbreaks and deaths. Changes in rainfall intensity, human interventions in the physical environment, and poor urban planning play a major role in driving catastrophic floods. Emphasis should be put on understanding flood causes and impacts on vulnerable societies, controlling water-borne diseases, and recognizing the importance of compiling relevant and reliable flood information. Extreme rainfall in this dry region could be an asset for attenuating the regional water scarcity status if well harvested and managed. We hope this paper will induce the hydroclimate scholars to carry out more flood studies for the Sahel. It is only then encumbered meaningful opportunities for flood risk management can start to unveil

Genital-Sparing Cystectomy versus Standard Urethral-Sparing Cystectomy Followed with Orthotopic Neobladder in Women with Bladder Cancer: Incidence and Causes of Hypercontinence with an Ultrastructure Study of Urethral Smooth Muscles

BACKGROUND: Bladder cancer in women is an indication for radical cystectomy (RC) when the tumour is confined muscle-invasive bladder cancer (MIBC) of T2 N0M0, or high risk progressive non-muscle invasive bladder cancer (NMIBC). Radical cystectomy is either genital-sparing cystectomy (GSC) or standard urethra-sparing cystectomy (USC) that is followed with orthotopic ileal neobladder (ONB). Post-operative chronic retention “Hypercontinence†had been reported in different series following URS or GSC and ONB. In long-term follow-up, we evaluated the functional outcome of women who developed hypercontinence after USC or GSC and ONB. AIM: An ultrastructure study of female urethral smooth muscle was done to elucidate the underlying causes of hypercontinence. MATERIAL AND METHODS: Retrospective study was conducted on 71 women who underwent RC and ONB, 45women had undergone USC, and 26 women had GSC, follow-up ranged from 5 to 15 years. Ultrastructure studies were done on 5 urethral biopsy specimens from 5 women who had hypercontinence, and 4 biopsies were from a normal control. RESULTS: Follow-up showed that women who had undergone USC and ONB, 28.88% developed hypercontinence, where in the series of GSC and ONB three women out of 26 developed hypercontinence (7.80%). Three women who had hypercontinence following USC and ONB, they developed stones in the ileal pouch. Ultrastructure study of urethral smooth muscles in women who had hypercontinence showed organized collagen fibrils, absent myelin sheath, and non-detected lymphatic vessels. Normal urethra showed collagen fibrils within the interstitial matrix, preserved myelin sheath of nerve fibres, the presence of lymphatic vessels in the matrix. CONCLUSION: The present study shoes that GSC with ONB leads to the minimal incidence of hypercontinence (7.80%), while standard USC lead to higher incidence (28.88%). Ultrastructure changes of the female urethra who had hypercontinence were fibrotic changes, loss of myelin sheath and minimal vascularity, their findings explains the underlying cause of hypercontinence and support the technique of GSC rather than the standard USC

Potential Utilization of Alternative Construction Materials in Qatar, in lieu of Conventional Washed Sand

Natural sand that has been washed is an essential material used in infrastructure development and construction projects of all sizes. Due to the depletion of natural sand sources in Qatar, there has arisen a need to develop alternate materials to replace it. Substitutes such as wadi gravel, marine sand and manufactured sand, including crushed imported limestone, recycled sand and crushed gabbro have been considered and explored. Consequently, a proposal to encourage local washed sand producers to incorporate varying proportions of these alternate materials into the various material demands was considered by the Public Works Department, depending on the application in either structural and/or precast members. This paper primarily focuses on providing an overview of some of the available alternate materials to washed sand that could be utilized without affecting the physical, mechanical, or strength properties of concrete, precast, and other construction materials that use washed sand, while at the same time providing a long-lasting, durable and economically beneficial alternative material to the national economy