Effect of a mixture of caffeine and nicotinamide on the solubility of vitamin (B2) in aqueous solution

The effect of caffeine (CAF) and nicotinamide (NMD) on the solubility of a vitamin B2 derivative (FMN) has been evaluated for mixtures containing either a single hydrotrope (CAF or NMD) or the two hydrotropes simultaneously. A model for analysis of ternary systems, which takes into account all possible complexes between the molecules, has been developed and tested with experimental NMR data on the three-component mixture FMN–CAF–NMD. The results indicate that special attention should be given to the concentration of a hydrotropic agent used to enhance the solubility of a particular drug. A decrease in the efficacy of solubility of the vitamin on addition of large amounts of hydrotropic agent is expected in the two-component systems due to the increased proportion of self-association of the hydrotrope. It is found that a mixture of two hydrotropic agents leads to an increase in the solubility of the vitamin in three-component compared to the two-component system. Rather than using just one hydrotropic agent, it is proposed that a strategy for optimising the solubility of aromatic drugs is to use a mixture of hydrotropic agents

New approach of hidden data in the portable executable file without change the size of carrier file using statistical technique

The rapid development of multimedia and internet allows for wide distribution of digital media data. It becomes much easier to edit, modify and duplicate digital information. In additional, digital document is also easy to copy and distribute, therefore it may face many threats. It became necessary to find an appropriate protection due to the significance, accuracy and sensitivity of the information. The strength of the hiding science is due to the non-existence of standard algorithms to be used in hiding secret messages. Also there is randomness in hiding methods such as combining several media (covers) with different methods to pass a secret message. Furthermore, there is no formal method to be followed to discover a hidden data. In this paper, a new information hiding system is presented. The aim of the proposed system is to hide information (data file) in an execution file (EXE) without change the size of execution file. The new proposed system is able to embed information in an execution file without change the size of execution file. Meanwhile, since the cover file might be used to identify hiding information, the proposed system considers overcoming this dilemma by using the execution file as a cover file

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Forgotten ureteral stents: Risk factors, complications and management

Objectives: To assess complications of neglected stents, risk factors for the occurrence of complications, and management options and outcomes. Subjects and methods: A prospective study including patients presenting to our center with neglected polyurethane ureteral stents (indwelling for more than 6 months in the period from February 2012 to September 2015). We noted the complications of neglected stents (urinary tract infections (UTI), urinary obstruction, elevated creatinine, encrustations and stent fragmentation), management challenges (need for complex endo-urologic or open procedures). We evaluated potential risk factors for these complications (duration of stenting, lack of urinary acidification, cause of stent placement). Results: The study included 68 patients with mean age 49.3 ± 12.6 years 80.9% were males. Mean stenting duration 17.3 ± 12.7 months. A total of 29% of patients received urine acidifier while the stent was indwelling, 92% were stone formers, 60% presented with UTI and 25% presented with elevated creatinine. Preoperative non-contrast spiral CT abdomen and pelvis showed encrustations on the stent in 23.5% of patients and fragmented stent in 13%. The stent was removed by cystoscopy only as an outpatient procedure in 26 (38.3%) cases (7 of them with encrustation) while 42 (61.7%) cases needed more than simple cystoscopy. Management challenges included need for complex endourological interventions (URS, PCNL, cystolithotripsy or even open surgery). Lack of urinary acidification was a significant risk factor for UTI and stent fragmentation (P-value = 0.038 and 0.006, respectively). Stone former patients needed complex interventions (P = 0.046). UTIs were more likely with longer duration of stenting (P = 0.027). Conclusion: Forgotten ureteral stents are associated with significant complications. Urinary acidification is protective against complications. Patients with stones are more liable to forgotten stents complications. Keywords: Ureteral stents, Infection, Encrustations, Urinary acidificatio

Carbon dioxide solubilities in decanoic acid-based hydrophobic deep eutectic solvents

The solubility of CO2 in hydrophobic deep eutectic solvents (DESs) has been measured for the first time. Six different hydrophobic DESs are studied in the temperature range from 298 to 323 K and at CO2 pressures up to 2 MPa. The results are evaluated by comparing the solubility data with existing hydrophilic DESs and currently applied physical solvents and fluorinated ionic liquids. The DESs are prepared by mixing decanoic acid with a quaternary ammonium salt with different halide anions and alkyl chain lengths. The measured CO2 solubilities are similar to those found in renowned fluorinated ILs, while the heats of CO2 absorption are in the range of nonpolar solvents. The presented DESs show good potential to be used as CO2 capture agents

Wideband and flat-gain amplifier using high concentration Erbium doped fibers in series double-pass configuration

A wide-band and flat gain Erbium-doped fiber amplifier (EDFA) is demonstrated using a gain media of high concentration Silica-based erbium doped fiber (EDF). The amplifier has two stages comprising a 1.5 m and 9 m long EDF optimized for C-band and L-band operations respectively, in a double-pass series configuration. The CFBG is used in both stages to allow a double propagation of signal and thus increases the attainable gain in both C- and L-band spectra. At an input signal power of -30 dBm, a flat gain of 22 dB is achieved with a gain variation of ±3 dB within a wide wavelength range from 1530 to 1600nm. The corresponding noise figure varies from 4 to 8 dB within this wavelength region

Food insecurity and HIV/AIDS: current knowledge, gaps, and research priorities.

Food insecurity and HIV/AIDS are intertwined in a vicious cycle that heightens vulnerability to, and worsens the severity of, each condition. We review current knowledge and research priorities regarding the impact of food insecurity on HIV transmission risk and clinical outcomes. Observational studies suggest that food insecurity is associated with increased HIV transmission risk behaviors and decreased access to HIV treatment and care. Among individuals receiving antiretroviral therapy (ART), food insecurity is associated with decreased ART adherence, reduced baseline CD4 cell count, incomplete virologic suppression, and decreased survival. Integration of food security interventions into HIV/AIDS treatment programs is essential to curtail the HIV/AIDS epidemic and improve health and quality of life among those infected. Longitudinal research applying validated measurement tools is needed to better understand the mechanisms through which food insecurity adversely impacts HIV transmission, treatment, and care. Research should compare the effectiveness of various food assistance and livelihood strategies