Optical properties of strain-engineered multilayer Si/SiGe nanostructures

The long carrier radiative lifetimes in indirect band gap semiconductors such as crystalline Si (c-Si) and Ge impede the development of efficient light-emitting devices and lasers. Multilayer Si/SiGe nanostructures are considered to be the strong candidates for efficient and high-speed optoelectronic devices integrated into CMOS platforms. Since c-Si and Ge have a considerable lattice mismatch of ~ 4.2%, Si/Si1-xGex(x \u3c 0.5) nanostructures in the form of nano-layers (NLs) or cluster multilayers (CMs) modify the band structure and create non-uniform strain distribution. Engineering of Si/Si1-xGexnanostructures with the predicted composition and interface abruptness, which controls spatial separation between electrons and holes and carrier radiative recombination rate, is critical in producing the desired fast and efficient photoluminescence (PL) peaked around 0.8-0.9 eV. This study investigates the structural, optical, and thermal properties of Si/Si1- xGexnanostructures with different layer thicknesses, Ge compositions, and SiGe heterointerface abruptness. A comprehensive experimental and theoretical analysis of Raman scattering in various Si/Si1-xGexmultilayered nanostructures with well-defined Ge composition (x) and layer thicknesses is presented. Using Raman and transmission electron microscopy data, Si/SiGe intermixing and strain are discussed and modeled. The studied samples exhibit significant dependence of the Raman scattering intensity on the excitation light penetration depth. Local temperature and thermal conductivity are calculated by analyzing the measured Stokes and anti -Stokes Raman spectra, and the developed model of heat dissipation in the samples under an intense laser illumination is in a good agreement with the experiment. A correlation is found between the SiGe/Si volume fraction ratio and thermal conductivity, which is explained and suggestions are made of applications of the developed model in the field of thermoelectric, electronic, and optoelectronic devices. In this thesis, PL measurements are focused on specifically designed Si/Si1-xGexnanostructures with a single 3-5 nm thick Si1-xGex layer with x ≈ 8% incorporated into Si/Si0.6Ge0.4 CMs. Under pulsed laser excitation, the PL decay associated with the Si0.92Ge0.08 N L is found to be nearly a 1000 times faster compared to that in Si/Si0.6Ge0.4 CMs, and the SiGe NL PL intensity does not saturate as a function of excitation energy density up to 50 mJ/cm2 . These dramatic differences in the observed PL properties are attributed to the difference in the structures of the Si/SiGe NL and CM heteroi nterfaces. A model considering Si/SiGe heterointerface composition and explaining the fast and slow time-dependent recombination rates is proposed and found to be in excellent agreement with the experimental data

Raphanus sativus ameliorates atherogeneic lipid profiles in hypercholesterolemic rats and hypercholesterolemia-associated peroxidative liver damage

Objective: Raphanus sativus is a hugely used edible root vegetable. We investigated whether the feeding of the Raphanus sativus hot water extract (RSE) ameliorates atherogenic lipid profile and oxidative stress in hypercholesterolemia. Methods: After feeding of the RSE to hypercholesterolemic rats for 6 weeks, the levels of plasma and hepatic total cholesterol (TC), triglyceride (TG), and plasma high density lipoprotein-cholesterol (HDL-C) and fecal TC levels were studied. The effects of RSE on the hepatic enzymes, namely alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP), the levels of lipid peroxide (LPO) and liver histology were also evaluated. Results: Hypercholesterolemia increased the levels of TC and TG in the plasma and livers. The levels of ALT, AST and ALP in plasma and LPO in the liver also increased. The dietary RSE, however, significantly ameliorated the above atherogenic lipids and liver enzymes. The RSE significantly reduced the levels of LPO in the liver, suggesting an in vivo protection against of oxidative stress. The RSE also inhibited the in vitro Fenton’s reagent-induced oxidative stress, thus corroborating the in vivo anti-LPO actions of RSE. The levels of hepatic LPO were positively correlated with plasma AST (r=0.76; P <0.05) and ALT (r=0.43; P<0.05) levels. Histologically, the livers of the RSE-fed hypercholesterolemic rats exhibited lesser fatty droplets and reduced inflammatory cells. Conclusion: Finally, R. sativus extract lowers the cardiovascular disease risk factors under hypercholesterolemic situation by increasing the plasma/hepatic clearance of cholesterol and improving the hypercholesterolemia-induced oxidative damage of hepatic tissues

COMMON MUSCULOSKELETAL PROBLEMS ARISES AMONG WOMEN AFTER PARTURITION AT SELECTED AREA OF BANGLADESH

Background: Pregnancy increases the susceptibility to developing musculoskeletal diseases. Postpartum musculoskeletal issues are frequently observed after childbirth, causing significant discomfort and distress for women. Purpose:To identify the common musculoskeletal problems that arises among women after the event of parturition at a selected area of Bangladesh. Methods:A cross-sectional study of Dhaka hospital postpartum mothers with musculoskeletal complaints was conducted. Study sites were Enam Medical College and Super Medical Hospital. Convenience sampling yielded 112 eligible individuals. Ethics, hospital approval, and participant anonymity were crucial. Face-to-face interviews using questionnaires and VAS were used to collect data. We obtained informed consent from participants to ensure confidentiality and withdrawal. We followed WHO and Bangladesh Medical Research Council ethical guidelines to ensure research integrity. Results:The Bangladeshi postpartum women study revealed common musculoskeletal disorders and their relationships. The majority of participants, 23–27 (55%) with one or two children, reported low back pain (57.1%), pelvic girdle discomfort (67.9%), and urine incontinence (38.4%). Pelvic girdle pain, diastasis recti, and urine incontinence were linked to childbirth. greater kids mean greater pain. The OREBRO scale showed varying severity (mean score: 101.64 ± 12.56). Childbirth affected musculoskeletal complaints, as shown by OMPQ ratings and participant age. This study prepares for more interventions. Conclusion:The study proposes that these findings can serve as fundamental information for the development of management and assessment programs in the postpartum musculoskeletal population

Conversion of waste plastic (low density polyethylene) to alternative resources

Plastic pollution has become one of the top issues at present throughout the world. In Asian continent plastic pollution is found at the highest rate and Bangladesh is ranking as the 10th number of plastic wastes producer. To minimize the plastic pollution its management is necessary. To do that we tried to convert the plastic wastes as alternative resources for example plastic tiles or plastic tobs. The study was conducted at Jashore University of Science and Technology campus where polyethylene plastic wastes are found available. Molten LDPE were mixed with varying proportion of sand to conduct two experiments. First one is the preparation of plastic tiles and the second one is the making of tobs. Both of the two experiments kept in incubation under water for 7 and 14 days and experimental characterization such as water absorption variation, compressive strength, SEM, FTIR and EDX were done using standard procedures. Density and water absorption changes with the increase in plastic percentage in both the two experiments. In the 1st experiment, compressive strength was done and showed that at the increase of plastic % up to 45% tiles could bear maximum load above 3000 psi that match the standard concrete tiles strength. In the case of EDX analysis, C, O and Hg showed at the highest peak than other elements in both the two experiments. In the surface internal structure of the 1st experiment, some structural deformation was noticed but in the 2nd experiments some cracks and cavities formation found on the naked eye. In the chemical structure of the 1st experiment showed C-O stretching, C=C stretching, O=C=O stretching whereas in the 2nd experiment, most of the tob samples showed C-O stretching, O-H stretching, C=C stretching and N-H stretching. The plastic tiles could be used in rare or rural area and plastic tobs could be used as decorative purposes. From the results, we found the satisfactory output of the product and could be used as alternative resources

Cyberbullying detection on social networks using machine learning approaches

The use of social media has grown exponentially over time with the growth of the Internet and has become the most influential networking platform in the 21st century. However, the enhancement of social connectivity often creates negative impacts on society that contribute to a couple of bad phenomena such as online abuse, harassment cyberbullying, cybercrime and online trolling. Cyberbullying frequently leads to serious mental and physical distress, particularly for women and children, and even sometimes force them to attempt suicide. Online harassment attracts attention due to its strong negative social impact. Many incidents have recently occurred worldwide due to online harassment, such as sharing private chats, rumours, and sexual remarks. Therefore, the identification of bullying text or message on social media has gained a growing amount of attention among researchers. The purpose of this research is to design and develop an effective technique to detect online abusive and bullying messages by merging natural language processing and machine learning. Two distinct freatures, namely Bag-of Words (BoW) and term frequency-inverse text frequency (TFIDF), are used to analyse the accuracy level of four distinct machine learning algorithms. © 2020 IEEE

MOESM1 of Contribution of target alteration, protection and efflux pump in achieving high ciprofloxacin resistance in Enterobacteriaceae

Additional file 1. Additional tables and figure

Serological Cross-Reaction Between O-Antigens of Shigella dysenteriae Type 4 and an Environmental Escherichia albertii Isolate

International audienceAn environmental freshwater bacterial isolate, DM104, appearing as Shigella-like colonies on selective agar plates was found to show strong and specific sero-logical cross-reactivity with Shigella dysenteriae type 4. Biochemical identification according to the analytical profile index, molecular serotyping by restriction of the amplified O-antigen gene cluster (rfb-RFLP), together with phylogenetic analysis of the 16S rRNA gene and multi-locus sequence analysis, identified the isolate as Esche-richia albertii. rfb-RFLP of DM104, revealed a profile different from that of S. dysenteriae type 4. However, western blot analysis of extracted lipopolysaccharides demonstrated strong cross-reactivity with S. dysenteriae type 4 using specific monovalent antisera and a lipopoly-saccharide gel banding profile similar to that of S. dy-senteriae type 4. The observed O-antigen cross-reaction between an E. albertii isolate and S. dysenteriae extends our knowledge of the extent of O-antigen cross-reaction within the Escherichia/Shigella group of organisms, and offers the possibility of using DM104 and similar cross-reacting strains as shigellosis vaccine candidates