21 research outputs found

    Wireless Quantum Key Distribution in Indoor Environments

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    Among all emerging quantum information technologies, quantum key distribution (QKD) is one of the most developed techniques. QKD harnesses the intrinsic laws of quantum mechanics to provide a method for distributing secret random keys, which can be used for data encryption and decryption between two intended users. QKD has already been demonstrated in different scenarios over optical fibre and in atmospheric channels. QKD has also been used for security assurance in several network settings, in addition of being commercially available today. Despite remarkable progress in QKD systems, convenient access to the developing quantum communications networks is still missing. Adopting QKD in mobile devices would enable such a service, particularly, in indoor environments. This is in line with the recent advancement in fabricating microchip-scale QKD devices, which would ease this incorporation into mobile devices. This work focuses on the access networks, and, in particular, it addresses the wireless mode of access in indoor environments for QKD networks. We find a practical regime of operation, where, in the presence of external light sources and loss, secret keys can be exchanged. We then propose practical configurations that would enable wireless access to hybrid quantum-classical networks. The proposed setups would allow an indoor wireless user, equipped with a QKD-enabled mobile device, to communicate securely with a remote party on the other end of the access network. We account for adverse effects of the background noise induced by Raman scattered light on the QKD receivers due to the transmission of both quantum and classical signals over the same fibre. In addition, we consider the loss and the background noise that arise from indoor environments. We consider a number of discrete and continuous-variable QKD protocols and study their performance in different scenarios. In our analysis we consider the asymptotic scenario, as well as the finite-size key effects. In the former case, an infinite number of signals are assumed to be exchanged between the sender and the recipient, whereas in the latter, which represents the practical scenario, a finite number of signals are exchanged between the two users. Our results indicate that a feasible regime of operation for wireless QKD exists. This makes the QKD technologies available to end users of a communications network

    Spectrophotometric Complex formation Study of Murexide with Nickel and Cobalt in Aqueous Solution

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    In the present study, the formation constant and the stoichiometry of murexide complexes with Co (II) and Ni (II) have been determined spectrophotometrically in aqueous solution at 25oC. Two experimental parameters governed the complex formation, pH and time, have been investigated. The formation and stoichiometry constants have been determined by two methods: Job's and mole ratio's methods. The absorption maxima for Co-murexide and Ni-murexide complexes were: 480, 460 nm, respectively. The two Spectrophotometric methods confirm the formation of 2:1 (M:L) complexes with stability arrange of: Co > Ni. The formation constants (Kf) determined by the Job's method were as follows: 2.06x1014 and 1.21x1011 for Co-murexide and Ni-murexide, respectively. Also, using mole ratio's method, the formation constants were found to be:  9.18x1011 and 6.01x1011. Molar absorptivity values of the studied complexes have also been determined (by Job's and mole ratio's methods) and the average values were: 18235 and 13284 l/mol.cm for Co and Ni, respectively

    Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

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    BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

    Clinical Presentation, Management, and Outcome of Patients with Incidental Renal Angiomyolipoma in Qatar

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    Objectives: Our study aimed to analyze the clinical presentation, management, and outcome of renal angiomyolipoma patients incidentally detected upon computed tomography (CT) examination. Methods: Between 2004 and 2008, all patients who underwent abdominal CT examination for any reason at the radiology department at Hamad General Hospital, Qatar were retrospectively reviewed. The diagnosis of renal angiomyolipoma was based on abdominal CT evaluation. Angiomyolipoma patients were followed-up by CT evaluation as per standard care for three years to observe any change in size and outcome. Results: A total of 13,115 patients were screened, of which 56 (40 females and 16 males) had renal angiomyolipoma. The mean age of patients was 52±13 years with 46% Qatar nationals. The majority (95%) of cases had unilateral tumors (52% right-sided and 43% left-sided). Twenty-six cases showed increase in tumor size and the median increase was 0.5cm (0.1–3.6). Surgical intervention was required in four (7%) cases with tumor size ≥4cm. The overall mortality on follow-up was 7%. The cause of death included metastasis, renal failure, hepatic failure and mesenteric thromboembolism. Conclusion: Renal angiomyolipoma is an uncommon benign tumor with an overall prevalence of 0.4% in Qatar. It has characteristic clinical features and its recognition is often challenging for proper clinical diagnosis and treatment in asymptomatic patients. Asymptomatic patients need regular radiological surveillance. In contrast, surgical interventions are mainly required in symptomatic patients with increased tumor size (≥4cm). Timely diagnosis and treatment is necessary to avoid complications such retroperitoneal hemorrhage and renal impairment

    Molecular Typing, Antibiogram and PCR-RFLP Based Detection of Aeromonas hydrophila Complex Isolated from Oreochromis niloticus

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    Motile Aeromonas septicemia is a common bacterial disease that affects Oreochromis niloticus and causes tremendous economic losses globally. In order to investigate the prevalence, molecular typing, antibiogram and the biodiversity of Aeromonas hydrophila complex, a total of 250 tilapia (Oreochromis niloticus) were collected randomly from 10 private tilapia farms (25 fish/farm) at El-Sharkia Governorate, Egypt. The collected fish were subjected to clinical and bacteriological examinations. The majority of infected fish displayed ulcerative necrosis, exophthalmia, and internal signs of hemorrhagic septicemia. The prevalence of A. hydrophia complex was 13.2%, where the liver was the most predominant affected organ (54.1%). Polymerase chain reaction (PCR) was used to verify the identification of A. hydrophila complex using one set of primers targeting gyrB as well as the detection of virulent genes (aerA, alt, and ahp). All isolates were positive for the gyrB-conserved gene and harbored aerA and alt virulence genes. However, none of those isolates were positive for the ahp gene. The antimicrobial sensitivity was carried out, where the recovered strains were completely sensitive to ciprofloxacin and highly resistant to amoxicillin. All retrieved strains showed the same phenotypic characteristics and were identical based on the restriction fragment length polymorphism (RFLP). Experimentally challenged fish presented a high mortality rate (76.67%) and showed typical signs as in naturally infected ones. In conclusion, the synergism of phenotypic and genotypic characterization is a valuable epidemiological tool for the diagnosis of A. hydrophila complex. RFLP is a fundamental tool for monitoring the biodiversity among all retrieved strains of A. hydrophia

    Protective Role of Nigella sativa Seed Meal and Its Alcohol Extract in Hepatorenal Syndrome Model in Rats

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    ABSTRACT Hepatorenal syndrome (HRS) is a major health problem where the functions of both liver and kidney are affected. The aim of the present research was to evaluate the protective effect of Nigella sativa meal and its ethanol extract in hepatorenal syndrome model in rats. Proximate composition and amino acid contents of Nigella sativa meal were analyzed. Total phenolic contents and phenolic compounds were determined in the ethanol extract. HRS was induced in rats via intraperitoneal injection of galactosamine. Three weeks prior to HRS induction, one group of rats was given daily oral dose of Nigella sativa meal alcohol extract, another group was fed on diet containing Nigella sativa meal, the third group served as control with HRS. A control normal group was run without any treatments. Different biochemical and nutritional parameters were followed. Gene expression of Interlukin 6 (IL-6) in both liver and kidney was determined. Safety of ethanol extract was assessed through acute toxicity test. Results showed that Nigella sativa meal contain 27.1% protein and a Fischer ratio of 3.303. Total phenolic content was 42.64 ± 0.929 mg gallic acid equivalent/g dry ethanol extract, identified phenolic compounds were protochatechuic, chlorogenic, vanillic, sinapic, coumaric and cinnamic acid and chrysin. HRS control group showed liver and kidney dysfunction reflected in the elevated plasma creatinine, urea, transaminases activity, total and direct bilirubin and endothelin 1 and urinary N-acetyl-β-DGlucosaminidase together with reduction in plasma albumin and creatinine clearance. Treatment with either forms of Nigella sativa significantly improved all determined parameters except for creatinine and creatinine clearance. Reduction in hemoglobin, plasma total antioxidant capacity and calcium along with elevation of plasma malondialdehyde and tumor necrosis factor-α were noticed in HRS control. All these parameters were significantly improved on treatment with Nigella sativa meals and extract except for calcium in case of the extract. Total cholesterol and high density lipoprotein cholesterol showed dyslipidemia in HRS control which were significantly ameliorated on consumption of Nigella sativa meals and extract. Liver and kidney Interlukin 6 gene expression was significantly enhanced in HRS control and significantly down regulated on treatment with Nigella sativa meals and extract. Ethanol extract showed complete safety on the highest tested dose
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