Disposable electrochemical sensor using graphene oxide – chitosan modified carbon-based electrodes for the detection of tyrosine

Despite the many recent advances in disposable and wearable sensing technologies for point of care testing (POCT), few affordable, flexible, and disposable sensors are available for the detection of tyrosine (Tyr), a valuable biomarker for metabolic and neurodegenerative diseases. In this regard, the disposable screen-printed electrodes on flexible substrates are attractive. However, current screen-printed approaches for the detection of Tyr use rigid ceramic substrates, expensive metal nanoparticle conductive inks and stiff metal or metal oxide-based sensitive materials, that are not suitable for single-use disposable or wearable POCT devices. To address these challenges, this work presents a flexible and disposable electrochemical sensor using graphene oxide – chitosan (GO-CS) modified carbon-based electrodes for the detection of Tyr. The affordable and easy to fabricate sensor consists of a three-carbon electrode system screen printed on a flexible, low-cost polyvinyl chloride (PVC) substrate. GO and CS were chosen as the sensitive nanocomposite due to their natural abundance and excellent electrochemical sensing properties. Quantitative determination of Tyr using DPV revealed a linear proportional response between 1 and 100 μM, with a correlation coefficient of 0.9993. The GO-CS-screen-printed carbon sensor (SPCS) also offers a linear range detection limit of 5.86 μM, and excellent sensitivity (0.0846 μA μM-1) and repeatability (RSD = 4.02%). The GO-CS-SPCS thereby provides a promising platform for the active sensing elements of single-use, disposable, and wearable POCT devices suitable for early diagnosis and monitoring of metabolic or neurodegenerative diseases or nutritional management

CLINICAL EVALUATION OF COMPARATIVE AND COMBINED EFFECT OF POLYHERBAL MICROBICIDE (BASANT) AND SELECTED PROBIOTICS IN THE TREATMENT OF RECCURRENT VAGINOSIS - A PHASE II PLACEBO CONTROLLED TRIAL

Background: Vaginosis is a widely prevalent syndrome in women. Treatment with one or more antibiotics cures invariably the infections. However recurrence is frequent and pH of the vagina is not always restored to the normal acidic range. This trial was conducted to determine whether a Polyherbal Microbicide BASANT or three selected strains of Probiotics Lactobacilli alone or the two in combination can regress Vaginosis, bring down the vaginal pH to acidic range and restore healthy vagina with colonised Lactobacilli.Methods: Women suffering from recurrent episodes of vaginosis were given capsules of either BASANT, Probiotics, Combination of the two or Placebo capsules for insertion in vagina for 7 nights. On day 10, Pelvic examination, pH, Whiff test, Gram stain for Clue cells and swab taken for culture of lactobacilli.Results: BASANT regressed Vaginosis in 14/ 20, Probiotics in 13/20, Combination of the two in 19/ 20 women and Placebo in 1/ 20 women.Conclusion: While both Polyherbal microbicide BASANT and the three strains of the lactobacilli cured Vaginosis in 65 to 70% of women, the combination was highly effective in curing 95% of women

Cu-Doped TiO2: Visible Light Assisted Photocatalytic Antimicrobial Activity

Surface contamination by microbes is a major public health concern. A damp environment is one of potential sources for microbe proliferation. Smart photocatalytic coatings on building surfaces using semiconductors like titania (TiO2) can effectively curb this growing threat. Metal-doped titania in anatase phase has been proven as a promising candidate for energy and environmental applications. In this present work, the antimicrobial efficacy of copper (Cu)-doped TiO2 (Cu-TiO2) was evaluated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) under visible light irradiation. Doping of a minute fraction of Cu (0.5 mol %) in TiO2 was carried out via sol-gel technique. Cu-TiO2 further calcined at various temperatures (in the range of 500⁻700 °C) to evaluate the thermal stability of TiO2 anatase phase. The physico-chemical properties of the samples were characterized through X-ray diffraction (XRD), Raman spectroscopy, X-ray photo-electron spectroscopy (XPS) and UV⁻visible spectroscopy techniques. XRD results revealed that the anatase phase of TiO2 was maintained well, up to 650 °C, by the Cu dopant. UV⁻vis results suggested that the visible light absorption property of Cu-TiO2 was enhanced and the band gap is reduced to 2.8 eV. Density functional theory (DFT) studies emphasize the introduction of Cu+ and Cu2+ ions by replacing Ti4+ ions in the TiO2 lattice, creating oxygen vacancies. These further promoted the photocatalytic efficiency. A significantly high bacterial inactivation (99.9999%) was attained in 30 min of visible light irradiation by Cu-TiO2

MoS2 Modified Screen Printed Carbon Electrode Based Flexible Sensor for Detection of Copper

Monitoring of heavy metal ions in aquatic environment can be a tedious process, especially in harsh, logistically challenging field conditions. This work demonstrates the detection of copper ions in water using a low-cost screen printed 2D molybdenum disulfide (MoS2) nanoparticle based electrochemical sensor. To deal with the common field-testing challenges, an easily disposable, flexible, compact sized reliable sensor was fabricated using a screen-printing technique. The developed sensor shows an excellent performance with a linear range of 5 µM to 1000 µM, a low limits of detection (LOD) value of just 0.3125 µM, and high repeatability with standard deviation less than 0.5%. With this performance and attractive attributes such as flexible form factor, low-cost fabrication and disposability etc. the presented sensor shows a great potential for practical applications in soil and water monitoring

The effect of temperature on permittivity measurements of aqueous solutions of glucose for the development of non-invasive glucose sensors based on electromagnetic waves

This article presents for the first time an empirical study that shows the importance of considering temperature when analyzing the permittivity (dielectric constant) of aqueous glucose solutions of various concentrations. The permittivity is a parameter that is investigated by researchers as a biomarker for non-invasive measurement of glucose without drawing blood. The development of this technology will allow personalized healthcare diagnostics to monitor and prevent diabetes. Since human glucose levels in the blood vary in the range of a few milligrams per decilitre, estimating such small variations of glucose will require a highly accurate and repeatable sensing technology. Electromagnetic (EM) waves, specifically in the microwave and terahertz frequency ranges, have shown promise in detecting changes in the electrical properties of blood plasma as they relate to glucose concentration. However, it’s important to note that while this technology shows promise, it is still in the research and development phase. It is shown here that the body temperature can affect the accuracy of the blood glucose measurements. Experiments were conducted with different glucose concentration solutions under various temperatures and the complex permittivity of the glucose was studied across a wide frequency range from 400 MHz to 11 GHz. The rise in thermal energy normally causes dipolar liquids like water to vibrate and rotate disrupting the alignment of the dipoles in response to an electric field thereby reducing its permittivity. Empirical results however show that for aqueous solution of glucose the permittivity increases with rise in temperature from 16◦C to 37◦C. This is attributed to the polar nature of the water and glucose molecules that becomes more pronounced with increased thermal energy. Based on the experimental results an accurate analytical expression is derived that considers the temperature of the aqueous glucose solution. The accuracy of the analytical expression is shown experimentally to be above 99%. The findings from the study should enable the design of accurate noninvasive glucose monitoring devices based on electromagnetic sensing techniques

New insights into the efficient charge transfer of ternary chalcogenides composites of TiO2

Abstract A two-step solvothermal synthesis was adopted to prepare AgXSe2-TiO2 (X = In, Bi) composites. DFT study of the pristine parent samples showed the formation of the hexagonal phase of AgBiSe2, and tetragonal phase of AgInSe2 and TiO2, which corroborated the experimentally synthesised structures. Both the AgBiSe2-TiO2 and AgInSe2-TiO2 composites displayed enhanced visible light absorption and reduced band gap in the UV-DRS patterns. The XPS results exhibited a shift in binding energy values and the TEM results showed the formation of spherical nanoparticles of both AgBiSe2 and AgInSe2. The PL signals displayed delayed recombination of the photogenerated excitons. The as synthesised materials were studied for their photocatalytic efficiency, by hydrogen generation, degradation of doxycycline, and antimicrobial disinfection (E. coli and S. aureus). The composite samples illustrated more than 95 % degradation results within 180 min and showed 5 log reductions of bacterial strains within 30 min of light irradiation. The hydrogen production outcomes were significantly improved as the AgBiSe2 and AgInSe2 based composites illustrated 180-fold and 250-fold enhanced output compared to their parent samples. The enhanced photocatalytic efficiency displayed is attributed to the delayed charge recombination of the photogenerated electron-hole pairs in the AgXSe2-TiO2 interface. Formation of a p-n nano heterojunction for AgBiSe2-TiO2 and type II heterojunction for AgInSe2-TiO2 composite are explained

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Search for anomalous couplings in boosted WW/WZ -> l nu q(q)over-bar production in proton-proton collisions at root s=8TeV

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