Floating Drug Delivery Systems Using Metronidazole as a Model Drug Part I: By Effervescent Method

Gastric retentive dosage forms are highly useful for the delivery of many kinds of drugs. The use of floating dosage forms (FDFs) is one of the methods used to achieve prolonged gastric residence time (GRT). Formulation of Metronidazole (MDZ) as FDF provides an opportunity for both local and systemic drug action for eradication of Helicobacter pylori which is a gram-negative bacterium that is associated with gastric inflammation, peptic ulcer, and gastric cancer. This study was undertaken in order to formulate effervescent single-unit floating drug delivery system (FDDS) for MDZ. In the effervescent method, a carbon dioxide generating agent, e.g. sodium bicarbonate, was incorporated in hydrophilic polymer matrix together with MDZ. Different formulation parameters were studied and their effects on the floatation and in vitro drug release profiles were investigated. Polyvinyl pyrrolidone (PVP) provided rapid hydration of matrix, and this influence was decreased with time. Pectin was found to meet the requirements needed from a matrix for drug delivery applications including suitable mechanical properties to confine the gas, and to sustain MDZ release. The optimal amount of polymer and effervescent agent, lubricant agent concentration, and compression force were also demonstrated. The stability of the selected floating MDZ tablet formula (6) was also studied at different temperatures for three months and the calculated expiration date was found to be more than 4 year

The Effect of Vitamin C and Antacid Tablets (SDI) on the Pharmacokinetics of Aspirin Tablets (SDI) in Human

The study explored the effect of vitamin c and antacid on the pharmacokinetics of aspirin in human subjects.  The study was conducted in 12 healthy adults volunteers who were asked to take in the first study, two tablets of aspirin (300 mg) alone. In a second study, the same subjects were given  two tablets of aspirin (300 mg) together with one tablet of vitamin c 500 mg. Eventually, in the third study,  the subjects were administered  two tablets of aspirin (300 mg) and one capsule containing NaHCO3 (500 mg). The three studies were separated by one week wash out period.  In each study, urine was collected from each individual participated in the study at specific time intervals for up to24 hours post dosing to calculate the cumulative amount of salicylate excreted in urine. The excretion rate was plotted against the mid-time sampling time to calculate the elimination rate constant (K), and the elimination half-life (T0.5).  It was found from the current investigation that administration of vitamin c tablet with aspirin tablets reduce (K) values and elongate T0.5, whereas, NaHCO3 intake elevate K values and reduce T0.5 in all subjects participated in the study.             It can be concluded from the current investigation that administration of weak acid drugs like vitamin c, or weak base drugs like antacid have considerable effect on the residence of aspirin in the body and consequently its intensity and duration of clinical effect

Assessment of Indoor Microplastic Particles Pollution in Selected Sites of Mosul City

Among the most significant sources of microplastics (MPs) for humans is indoor dust. However, very few researchers have studied the properties and abundance of MPs that existed in dust from different indoor environments. The current study investigated microplastic fallout in 90 locations (5 kindergartens, 6 mosques, 5 schools, 10 shops, 5 cafeterias, 6 hospitals, 25 dormitories, 7 barber salons, 6 offices, 5 scientific laboratories, 5 pharmacies, and 5 medical clinics) during six months. Among the ninety sampling sites, the most significant average of MPs was actually found in the kindergartens (4.743x103 ± 427 MP/m2 /d), in contrast, the lowest abundance was in the medical clinics (302 x102 ±62 MP/m2 /d). The majority of indoor dust samples contained MPs in the form of fibers. The dominant colour of dust samples was transparent, followed by black, red, blue, green, and yellow. A total of six types of polymers were identified, including polystyrene (PS, 39%), polyethylene terephthalate (PET, 20%), polypropylene (PP, 17%), polyethylene (PE, 13), polyamide (PA, 7%) and polyvinyl chloride (PVC, 3%). PS, PET, and PP represent most of the MPs polymer types discovered in indoor dust samples from various locations. These polymers are frequently used in fabrics, furniture, carpets, packaging, and synthetic fibers. Statistical analysis was performed on the results using Excel 2019. The results showed that there were statistically significant differences in each site with the other sites, except between (schools and mosques), (pharmacies, and medical clinics). The similarity between these sites in terms of people’s activity or in terms of furniture, the lack of carpets and curtains could explain the insignificant difference

Spiking Behaviour in Laterally-Coupled Pairs of VCSELs With Applications in Neuromorphic Photonics

We report a theoretical study on laterally-coupled pairs of vertical-cavity surface-emitting lasers (VCSELs) operated under conditions that generate or suppress high-speed optical spiking regimes, and show their potential in exemplar functionalities for use in photonic neuromorphic computing systems. The VCSEL numerical analysis is based on a system of five coupled mode equations, which, for the case of weak coupling, are reduced to a set of three equations that predict the saddle-node stability boundary in terms of device parameters and operating conditions. These results guide numerical simulation to demonstrate multiple neuron-like dynamics, including single- and multiple-spike emission, spiking inhibition, and rebound spiking directly in the optical domain. Importantly, these behaviours are obtained at sub-nanosecond rates, hence multiple orders of magnitude faster than the millisecond timescales of biological neurons. The mechanisms responsible are explained by reference to appropriate phase portraits. The coupled VCSELs model is then used for demonstration of high-speed, all-optical digital-to-spiking encoding and for representation of digital image data using rate-coded spike trains

Time Evolution of a Supply Chain Network: Kinetic Modeling

Resilient supply chains are often inherently dependent on the nature of their complex interconnected networks that are simultaneously multi-dimensional and multi-layered. This article presents a Supply Chain Network (SCN) model that can be used to regulate downstream relationships towards a sustainable SME using a 4-component cost function structure - Environmental (E), Demand (D), Economic (E), and Social (S). As a major generalization to the existing practice of using phenomenological interrelationships between the EDES cost kernels, we propose a complementary time varying model of a cost function, based on Lagrangian mechanics (incorporating SCN constraints through Lagrange multipliers), to analyze the time evolution of the SCN variables to interpret the competition between economic inertia and market potential. Multicriteria decision making, based on an Analytic Hierarchy Process (AHP), ranks performance quality, identifying key business decision makers. The model is first solved numerically and then validated against real data pertaining to two Small and Medium Enterprises (SMEs) from diverse domains, establishing the domain-independent nature of the model. The results quantify how increases in a production line without appropriate consideration of market volatility can lead to bankruptcy, and how high transportation cost together with increased production may lead to a break-even state. The model also predicts the time it takes a policy change to reinvigorate sales, thereby forecasting best practice operational procedure that ensures holistic sustainability on all four sustainability fronts

Simulated dynamics of optically pumped dilute nitride 1300 nm spin vertical-cavity surface-emitting lasers

The authors report a theoretical analysis of optically pumped 1300 nm dilute nitride spin-polarised vertical-cavity surface-emitting lasers (VCSELs) using the spin-flip model to determine the regions of stability and instability. The dependence of the output polarisation ellipticity on that of the pump is investigated, and the results are presented in twodimensional contour maps of the pump polarisation against the magnitude of the optical pump. Rich dynamics and various forms of oscillatory behaviour causing self-sustained oscillations in the polarisation of the spin-VCSEL subject to continuouswave pumping have been found because of the competition of the spin-flip processes and birefringence. The authors also reveal the importance of considering both the birefringence rate and the linewidth enhancement factor when engineering a device for high-frequency applications. A very good agreement is found with the experimental results reported by the authors' group. © The Institution of Engineering and Technology 2014

Effects of Goat Manure Fertilization on Grain Nutritional Value in Two Contrasting Quinoa (Chenopodium quinoa Willd.) Varieties Cultivated at High Altitudes

In this study, the effects of goat manure fertilization (2, 4, 8, and 12 Tn/ha) on the grain yield, organic compounds, and mineral composition of two quinoa varieties (CICA-17 and Regalona Baer) were evaluated under field conditions in Northwest Argentina. The results indicate that fertilization improved the quinoa grain yield and total protein content. Low manure doses positively affected the fatty acid (FA) profile, and significant changes were determined for the monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acid contents of CICA-17 and on the saturated fatty acid (SFA) contents of R. Baer seeds. The amino acid contents were positively affected in CICA-17 and negatively in R. Baer. Soluble sugars (glucose, fructose, and sucrose), major elements (K, Si, P, Mg, Ca, and Na), minor elements (Fe, Mn, Al, Zn, and Cu), and ultratrace elements (Cr and Li) were detected and discussed in terms of their impact on human nutrition and health. Conclusively, manure addition affected some essential amino acids, the desaturase activity, the n6:n3 and SFA/UFA ratios, the atherogenic index, soluble sugars, and mineral content, and the fatty acid metabolism of each variety was differently affected, especially the C16 and C18 desaturase activity, which responded differently to various manure doses. Manure addition is a promising alternative to improve the nutritional quality and functionality of quinoa grains, but the response is not linear

First report of naturally infected Sergentomyia minuta with Leishmania major in Tunisia

International audienceBackground: Many sand fly species are implicated in the transmission cycle of Leishmania parasites around the world. Incriminating new sand flies species, as vectors of Leishmania is crucial to understanding the parasite-vector transmission cycle in different areas in Tunisia and surrounding countries. Findings: Seventy-four unfed females belonging to the genera Sergentomyia and Phlebotomus were collected in South Tunisia between June and November 2014, using sticky papers. PCR-RFLP (Restriction Fragment Length Polymorphism) analysis of the internal transcribed spacer 1 (ITS1) was used for Leishmania parasites detection and identification. Leishmania (L.) major (Yakimoff & Shokkor, 1914) was identified within two Sergentomyia (S.) minuta (Rondani, 1843) and one Phlebotomus papatasi (Scopoli, 1786). Conclusion: This is the first report of L. major identified from S. minuta in Tunisia. This novel finding enhances the understanding of the transmission cycle of L. major parasites of cutaneous leishmaniasis in an endemic area in South Tunisia