جستجوی مقالات مرتبط با کلیدواژه « sensitivity » در نشریات گروه « شیمی »

Pneumonia is a global health concern, causing significant morbidity and mortality, particularly among vulnerable populations. This study, conducted at Dr. Soetomo Regional Public Hospital (RSUD Dr. Soetomo), Surabaya, Indonesia, aimed to assess the causative pathogens, antibiotic sensitivity patterns, and the impact of empiric therapy on the clinical outcomes of pneumonia patients. The present study analyzed 324 cases from January to March 2023, categorizing pneumonia as community-acquired (CAP), hospital-acquired (HAP), and ventilator-associated (VAP). Gram-negative bacteria, predominantly Klebsiella pneumoniae, were the primary pathogens, with 44% being multidrug-resistant. Antibiotic sensitivity patterns highlighted the efficacy of amikacin, cefoperazone sulbactam, and meropenem against Gram-negative bacteria. Empiric therapy, mainly monotherapy, showed varied outcomes across pneumonia types. Clinical improvement was observed in 72.5% of CAP patients, while HAP and VAP patients faced challenges, with high mortality rates of 47.2% and 89.1%, respectively. Clinical stability in CAP correlated with age, culture results, multidrug resistance, pneumonia severity, and antibiotic class. In HAP, appropriate empiric therapy and pneumonia severity influenced clinical outcomes. Notably, VAP patients experienced poor outcomes irrespective of the variables studied. This study underscores the importance of local pathogen prevalence awareness and tailored empiric therapy to enhance pneumonia management, especially in HAP and VAP cases. Further research is warranted to refine treatment strategies and improve patient outcomes.

Numerous metal oxide nanomaterials, such as titanium dioxide (TiO2</sub>), tin oxide (SnO2</sub>), and zinc oxide (ZnO), are highly suitable for the fabrication of effective humidity sensors. Comparatively, ZnO is considered as metal oxide with the highest potential due to its unique properties, such as the enormous excitation binding energy of 60 meV, a direct wide bandgap (3.37eV), and the ability to be synthesized and grown at low temperatures. To further enhance the sensing performance of ZnO structure for humidity sensing, parameters such as the morphology and crystallinity of the ZnO structure can be optimized through control of synthesis conditions, such as precursor concentration, reaction time, temperature, and pH. Although various fabrication and characterization of ZnO nanostructures composited with other metal oxides have been published, there are insufficient investigations that highlight the performance of humidity sensors using ZnO alone. Therefore, this study provides a comprehensive analysis of the application of ZnO nanostructure in developing humidity sensors. The discussion in this review includes a summary of the recent development of humidity sensors and the parameters used to measure their sensing performances such as doping and compounding method. The study also highlighted the unique features of ZnO and the numerous methods used to synthesis ZnO, including sol-gel immersion, two-step solution, hydrothermal synthesis, and spin-coating process. In short, the intriguing development of ZnO-based humidity sensors would offer an alternative option to employ effective humidity-sensing devices in thin-film solar cells and ultraviolet (UV)-based applications.</em>

ZnO thin film of 80 nm thickness was deposited by the sol-gel spin coating method on SiO2/Si substrate and subsequently post-annealed at 500°C with a flow of oxygen for 60 min. Crystallographic structure of the sample was characterized by X-ray diffraction (XRD) method while a field emission scanning electron microscope (FESEM) was used to investigate the surface physical morphology and chemical composition. The sensitivity of the sample was tested to acetic acid vapor with different concentrations (20 ppm, 40 ppm, and 80 ppm) in the temperature range of 200-400 °C. The results showed that the ZnO thin film can be introduced as an acetic acid vapor sensor with a good reliability and detection limit of 20 ppm at the operating temperature of 320°C.

Abstract- Highly economic and selective method for the analysis of dopamine-receptor antagonist and antiemetic drug Metoclopramide is developed. In this method Metoclopramide is analyzed electrochemically by using pre-treated pencil graphite electrode (PTPGE) by differential pulse and cyclic voltammetry. The PTPGE showed very good result with significant enhancement of the peak current. The dependence of the current on pH, concentration and scan rate was investigated to optimize the experimental conditions for determination of Metoclopramide. The oxidative peak current increased linearly with the concentration of Metoclopramide in the range of 1.0×10-8 to 1.3×10-6 M. The limit of detection was found to be 1.29×10-11 M. The pre-treated electrode showed good selectivity, reproducibility and stability for the detection of trace Metoclopramide. The proposed method was successfully applied to Metoclopramide determination in pharmaceutical formulations and real samples.

The resonant frequency and sensitivity of an atomic force microscope (AFM) cantilever with assembled cantilever probe (ACP) have been analyzed and a closed-form expression for the sensitivity of vibration modes has been obtained. The proposed ACP comprises an inclined cantilever and extension, and a tip located at the free end of the extension, which makes the AFM capable of topography at sidewalls of microstructures. Because the extension is not exactly located at one end of the cantilever, the cantilever is modeled as two beams. In this study, the effects of the interaction stiffness and damping, and also some geometrical parameters of the cantilever on the resonant frequencies and sensitivities are investigated. Afterwards, the influence of the interaction stiffness and damping, and the geometrical parameters such as the angles of the cantilever and extension, the connection position of the extension and the ratio of the extension length to the cantilever length on the sensitivity and resonant frequency are investigated. The results show that the greatest flexural modal sensitivity occurs at a small contact stiffness of the system, when the connection position and damping are also small. The results also indicate that at low values of contact stiffness, an increase in the cantilever slope or a decrease in the angle between the cantilever and extension can rise the resonant frequency while reduces the sensitivity.

Ru/Al2O3 catalysts were prepared by conventional incipient wetness impregnation as well as colloid deposition of RuCl3 precursor via in situ reduction with ethylene glycol (polyol) method on alumina support. The samples were characterized by TEM, XRD and TPR techniques. The catalytic performance tests were carried out in a fixed-bed micro-reactor under different operating conditions. Ethylene glycol as the reducing agent in the polyol methodproduced well-dispersed and uniform ruthenium nanoparticles with an average diameter of 7 nm supported on Al2O3. In conventional method, however, reduction by hydrogen resulted in considerably larger particles with average size of 12 nm.The Ru/Al2O3 catalyst prepared by polyol method exhibited three-fold higher activity in ammonia synthesis compared to the catalyst prepared by conventional method. The turnover frequency ratio of ammonia synthesis of polyol to conventional catalyst was estimated to be 2.1 at 450°C implying the reaction is structure-sensitive over Ru-based catalysts.

The aim of this study is experimental assay of sensitivity and stability of a bimetallic silver/gold SPR sensor chip. This chip utilizes the sensitivity of the silver and the stability of the gold. Moreover, the Silver layer (instead of usual Cr or Ti layer) was used as an adhesive intermediate layer between the Gold layer and the glass substrate. The optimization of the Gold/Silver thickness using SPR analysis and physical and chemical stability tests showed that the 20/30 gold/silver composite resulting in a better precision and more stable SPR sensing chip.