In the present scenario, pharmaceutical and biomedical sectors are facing the challenges of continuous increase in the multidrug‐resistant (MDR) human pathogenic microbes. Re‐emergence of MDR ...microbes is facilitated by drug and/or antibiotic resistance, which is acquired way of microbes for their survival and multiplication in uncomfortable environments. MDR bacterial infections lead to significant increase in mortality, morbidity and cost of prolonged treatments. Therefore, development, modification or searching the antimicrobial compounds having bactericidal potential against MDR bacteria is a priority area of research. Silver in the form of various compounds and bhasmas have been used in Ayurveda to treat several bacterial infections since time immemorial. As several pathogenic bacteria are developing antibiotic resistance, silver nanoparticles are the new hope to treat them. This review discusses the bactericidal potential of silver nanoparticles against the MDR bacteria. This multiactional nanoweapon can be used for the treatment and prevention of drug‐resistant microbes.
The paradigm modifications in the metallic crystals from bulky to micro-size to nano-scale have resulted in excellent and amazing properties; which have been the remarkable interests in a wider range ...of applications. Particularly, Ag NPs have much attention owing to their distinctive optical, chemical, electrical and catalytic properties that can be tuned with surface nature, size, shapes, etc. and hence these crystals have been used in various fields such as catalysis, sensor, electronic components, antimicrobial agents in the health industry etc. Among them, Ag NPs based disinfectants have paid attention due to the practical applications in our daily life. Therefore the Ag NPs have been used in different sectors such as silver-based air/water filters, textile, animal husbandry, biomedical and food packaging etc. In this review, the Ag NPs as a disinfectant in different sectors have been included in detail.
•Silver nanoparticles as a potent disinfectant•Applications of silver nanoparticles in Environmental, HAIs and industrial sectors•Role of silver nanoparticles for disinfections
Schematic representation for synthesis of silver nanoparticles. Display omitted
► Environmentally benign and efficient method ► Stable silver NPs better for catalysis ► Elemental silver NPs instead ...of their oxides ► Effective capping of silver NPs by sodium dodecyl sulfate in aqueous medium ► Excellent catalyst towards reduction of p-nitrophenol to p-aminophenol at RT.
Supported silver nanoparticles were synthesized via in situ sol–gel followed by reduction method with dextrose as reductant and sodium dodecyl sulfate as stabilizer. The synthesized nanoparticles were characterized by X–ray diffraction, transmission electron microscopy, Fourier transform Infra-Red spectroscopy and UV–visible measurements. The XRD peaks confirm the metallic face-centered cubic silver particles. The formation of silver nanoparticles was confirmed from the appearance of surface plasmon absorption maxima at 412nm; which shifted to the longer wavelengths after supported on titania host lattice. TEM showed the spherical nanoparticles with size in the range of 18–23nm. An efficient and simple method was reported for the reduction of 4-nitrophenol using titania-supported silver nanoparticles at room temperature. The reaction was first order with respect to the concentration of 4-nitrophenol with higher efficiency. Titania supported silver nanoparticles are reusable and stable heterogeneous catalyst.
TiO2/WO3 nanocomposites (NCs) were successfully prepared by ultrasonic-assisted sol-gel method and acid functionalized (sulfated) by using chlorosulfonic acid. Various physicochemical properties of ...as prepared NCs were studied by using X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy with energy dispersive analysis, transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence spectroscopy, UV visible diffused reflectance spectroscopy, and Brunauer-Emmett-Teller (BET) surface area analysis. It was confirmed that the active sulfonic groups are anchored onto the surface of binary NCs. Furthermore, the photocatalytic performance of this material was significantly higher for the degradation of Congo red and methyl red dyes. Both these azo dyes were degraded only within 120 min under visible light irradiation. Recyclability of this catalyst was also studied and it was found that even after five consecutive cycles the introduced catalyst retain its catalytic efficiency above 90%.
•Binary TiO2/WO3 NCs prepared by ultrasonic-assisted sol-gel method.•NCs were sulfated by using chlorosulfonic acid as a precursor.•Anchoring of sulfonic groups was revealed by FT-IR, EDX and XPS techniques.•Sulfonic groups retard electron-hole recombination as confirmed by PL spectroscopy.•Sulfated NC proved efficient visible active photocatalyst for azo dyes degradation.
Europium doped Yttrium oxide (Y2O3) nanophosphors with different doping concentrations were synthesized by simple and efficient sol-gel method. The structural, morphological and compositional study ...was carried out by using XRD, FE-SEM, TEM, EDS, XPS, etc. Results demonstrated that the material is highly crystalline with cubic (body centered) structure and the particles apparently are of spherical shape with particle size around ∼10–20 nm. EDS results show the presence of Eu-impurity evenly distributed. Optimization of luminescence properties of the material by varying the concentration and annealing temperature show maximum thermoluminescence (TL) sensitivity at 1600 °C for 10.0 M% of Eu, however, maximum photoluminescence (PL) intensity was achieved after annealing the nanophosphor at 1200 °C. It exhibits a strong red emission with a sharp peak at 612 nm under excitation with UV and visible light (λex = 260, 393, 466 nm). TL studies showed four peaks at 100, 117, 139, and 301 °C. However, the first peak fades completely in a day (apparently due to low peak temperature) but the other three peaks are quite stable. The TL response was found to be linear from 120 Gy to 1.0 kGy but becomes sub-linear later in the dose range 1.0–100 kGy.
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•Y2O3:Eu3+ nanophosphor was synthesized by simple and efficient sol-gel method.•The chemical compositions and binding energy information study was examined by X-Ray Photoelectron Spectroscopy (XPS) technique.•Thermoluminescence (TL) and Photoluminescence (PL) characteristics have been studied.•Y2O3:Eu3+ nanophosphor was exposed by gamma radiation and its TL response was studied up to 100 kGy dose.•The TL glow curves were deconvoluted by Computerized Glow Curve Deconvolution (CGCD) method.
The thermo-acoustic instabilities developed inside the combustor causes serious structural damage and reduces the life of power producing devices. The present work involves experimental investigation ...to assess effect of radial micro-jets air injection on thermo-acoustic instabilities and temperature in lateral planes. A co-axial pre-mixed gas burner used as the heat source inside the Rijke tube with variable location. Two types of Rijke tubes were used for experimental study, one is of steel with 75 mm internal diameter and 750 mm in length for the measurement of wall pressure, temperature and acoustics.
•In the first part of the study, acoustic instability zone for different inlet mass flow rates was identified.•In the second part of study, the entire cross-sectional of Rijke tube was divided into 193 subzones and temperatures were measured at 193 locations when instability was present.•In third part, again temperatures were measured at 193 locations with implementation of control method with complete suppression of thermo-acoustic instabilities.
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The recognition of bacterial lipoproteins by toll‐like receptor (TLR) 2 is pivotal for inflammation initiation and control in many bacterial infections. TLR2‐dependent signalling is currently ...believed to essentially require both adaptor proteins MyD88 (myeloid differentiation primary response gene 88) and Mal/TIRAP (MyD88‐adapter‐like/TIR‐domain‐containing adaptor protein). TLR2‐dependent, but MyD88‐independent responses have not been described yet. We report here on a novel‐signalling pathway downstream of TLR2, which does not adhere to the established model. On stimulation of the TLR2/6 heterodimer with diacylated bacterial lipoproteins, Mal directly interacts with the regulatory subunit of phosphoinositide 3‐kinase (PI3K), p85α, in an inducible fashion. The Mal–p85α interaction drives PI3K‐dependent phosphorylation of Akt, phosphatidylinositol(3,4,5)P3 (PIP3) generation and macrophage polarization. MyD88 is not essential for PI3K activation and Akt phosphorylation; however, cooperates with Mal for PIP3 formation and accumulation at the leading edge. In contrast to TLR2/6, TLR2/1 does not require Mal or MyD88 for Akt phosphorylation. Hence, Mal specifically connects TLR2/6 to PI3K activation, PIP3 generation and macrophage polarization.
Aims: To study platelet volume indices (PVI) in the spectrum of ischaemic heart diseases. Methods: A total of 210 cases were studied; 94 patients had unstable angina (UA) or acute myocardial ...infarction (AMI) diagnosed on the basis of history, characteristic electrocardiographic changes, and increased cardiac enzyme activities. Seventy patients had stable coronary artery disease (stable CAD) or were admitted for a coronary angiography or coronary artery bypass graft procedure. The third group comprised 30 age and sex matched healthy controls with no history of heart disease and a normal electrocardiogram. Results: All PVI—mean platelet volume (MPV), platelet distribution width (PDW), and platelet large cell ratio (P-LCR)—were significantly raised in patients with AMI and UA (mean MPV, 10.43 (SD, 1.03) fL; mean PDW, 13.19 (SD, 2.34) fL; mean P-LCR, 29.4% (SD, 7.38%)) compared with those with stable CAD (mean MPV, 9.37 (SD, 0.99) fL; mean PDW, 11.35 (SD, 1.95) fL; mean P-LCR, 22.55% (SD, 6.65%)) and the control group (mean MPV, 9.2 (SD, 0.91) fL; mean PDW, 10.75 (SD, l.42) fL; mean P-LCR, 20.65% (SD, 6.14%)). Conclusions: Larger platelets are haemostatically more active and are a risk factor for developing coronary thrombosis, leading to myocardial infarction. Patients with larger platelets can easily be identified during routine haematological analysis and could possibly benefit from preventive treatment. Thus, PVI are an important, simple, effortless, and cost effective tool that should be used and explored extensively, especially in countries such as India, for predicting the possibility of impending acute events.
•The test setup is unique to study thermo-acoustic instability and its control.•The proposed RI coefficient estimated by simultaneous measurement.•The proposed RI coefficient eliminate problem of ...arbitrary scale and units.•The proposed RI coefficient (0.5 –0) serves as an indicator of thermo-acoustics.
This study proposes a coefficient of Rayleigh Index (CRI) obtained by normalizing the acquired data which can circumvent the problem of arbitrary scale and unit while quantifying the Rayleigh Index. CRI is estimated from the simultaneous measurements of luminescence of a flame as an indicator of unsteady heat release and pressure fluctuation near the burner head. Experiments were carried out for six different mixture equivalence ratios ranging from 0.75 to 1.0 and a burner positioned at x/L = 0.2. The control technique of micro jets is found to completely suppress the thermo-acoustics by decoupling the pressure waves and unsteady heat release waves as indicated by increasing phase difference between them. The coefficient of Rayleigh Index is found to reduce to nearly zero with the use of radial micro jets for suppressing the thermo-acoustic instability. In such case, the flame luminescence was observed to significantly reduce. The proposed coefficient of Rayleigh index is very useful in quantifying the effectiveness of control technique for the thermo-acoustic instability.
Nickel oxide/polypyrrole (NiO/PPy) thin films were deposited by a two step process in which the NiO layer was electrodeposited potentiostatically from an aqueous solution of NiCl
2·6H
2O at pH 7.5 on ...fluorine doped tin oxide (FTO) coated conducting glass substrates, followed by the deposition of polypyrrole (PPy) thin films by chemical bath deposition (CBD) from pyrrole mixed with ammonium persulfate (APS). The NiO/PPy films were further characterized for their structural, optical, morphological and electrochromic properties. X-ray diffraction study indicates that the films composed of polycrystalline NiO and amorphous PPy. Infrared transmission spectrum reveals chemical bonding between NiO and PPy. Rectangular faceted grains were observed from scanning electron microscopy results. The electrochromic (EC) property of the film was studied using cyclic voltammogram (CV), chronoamperometry (CA) and optical modulation. The NiO/PPy presents superior EC properties than their individual counterparts. The coloration/bleaching kinetics (response time of few ms) and coloration efficiency (358
cm
2/C) were found to be improved appreciably. The dramatic improvement in electrochemical stability (from about 500 c/b cycles for PPy to 10,000 c/b cycles for NiO/PPy) was observed. This work therefore demonstrates a cost-effective and simple way of depositing highly efficient, faster and stable NiO/PPy electrodes for EC devices.
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