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排序方式: 共有143条查询结果,搜索用时 15 毫秒
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Strong Stokes and Upconversion Luminescence from Ultrasmall Ln3+‐Doped BiF3 (Ln=Eu3+, Yb3+/Er3+) Nanoparticles Confined in a Polymer Matrix 下载免费PDF全文
Heavy metal fluorides like BiF3 as a host for lanthanide ions are of interest as bismuth is the only heavy metal that is nontoxic. In this work, we report the synthesis of highly water‐dispersible ultrasmall BiF3 nanoparticles about 6 nm in size within a poly(vinyl pyrrolidone) matrix by a hydrothermal method. Microscopy analysis reveals that the nanoparticles are well separated and confined within the polymer network. These nanoparticles were found to be excellent hosts for lanthanide (Ln3+) ions. Through suitable Ln3+ doping, BiF3 exhibits strong emissions in the visible region upon both UV and near infrared (NIR) excitations. The non‐toxicity of both bismuth and PVP can be advantageous for the potential use of BiF3 nanoparticles in drug delivery and bioimaging. 相似文献
3.
Harinash Rao Sulin Choo Sri Raja Rajeswari Mahalingam Diajeng Sekar Adisuri Priya Madhavan Abdah Md. Akim Pei Pei Chong 《Molecules (Basel, Switzerland)》2021,26(7)
Biofilms play an essential role in chronic and healthcare-associated infections and are more resistant to antimicrobials compared to their planktonic counterparts due to their (1) physiological state, (2) cell density, (3) quorum sensing abilities, (4) presence of extracellular matrix, (5) upregulation of drug efflux pumps, (6) point mutation and overexpression of resistance genes, and (7) presence of persister cells. The genes involved and their implications in antimicrobial resistance are well defined for bacterial biofilms but are understudied in fungal biofilms. Potential therapeutics for biofilm mitigation that have been reported include (1) antimicrobial photodynamic therapy, (2) antimicrobial lock therapy, (3) antimicrobial peptides, (4) electrical methods, and (5) antimicrobial coatings. These approaches exhibit promising characteristics for addressing the impending crisis of antimicrobial resistance (AMR). Recently, advances in the micro- and nanotechnology field have propelled the development of novel biomaterials and approaches to combat biofilms either independently, in combination or as antimicrobial delivery systems. In this review, we will summarize the general principles of clinically important microbial biofilm formation with a focus on fungal biofilms. We will delve into the details of some novel micro- and nanotechnology approaches that have been developed to combat biofilms and the possibility of utilizing them in a clinical setting. 相似文献
4.
Highly Luminescent Colloidal Eu3+‐Doped KZnF3 Nanoparticles for the Selective and Sensitive Detection of CuII Ions 下载免费PDF全文
Shyam Sarkar Manjunath Chatti Dr. Venkataramanan Mahalingam 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(12):3311-3316
This article describes a green synthetic approach to prepare water dispersible perovskite‐type Eu3+‐doped KZnF3 nanoparticles, carried out using environmentally friendly microwave irradiation at low temperature (85 °C) with water as a solvent. Incorporation of Eu3+ ions into the KZnF3 matrix is confirmed by strong red emission upon ultraviolet (UV) excitation of the nanoparticles. The nanoparticles are coated with poly(acrylic acid) (PAA), which enhances the dispersibility of the nanoparticles in hydrophilic solvents. The strong red emission from Eu3+ ions is selectively quenched upon addition of CuII ions, thus making the nanoparticles a potential CuII sensing material. This sensing ability is highly reversible by the addition of ethylenediaminetetraacetic acid (EDTA), with recovery of almost 90 % of the luminescence. If the nanoparticles are strongly attached to a positively charged surface, dipping the surface in a CuII solution leads to the quenching of Eu3+ luminescence, which can be recovered after dipping in an EDTA solution. This process can be repeated for more than five cycles with only a slight decrease in the sensing ability. In addition to sensing, the strong luminescence from Eu3+‐doped KZnF3 nanoparticles could be used as a tool for bioimaging. 相似文献
5.
Thimmaiah Srivatsa Wahidi Tabish Yadav Ajay Kumar Mahalingam Arun 《Journal of Thermal Analysis and Calorimetry》2020,141(6):2219-2229
Journal of Thermal Analysis and Calorimetry - Natural circulation loop (NCL) is a geometrically simple heat transfer device in which fluid flow occurs due to density gradient of loop fluid, induced... 相似文献
6.
Mr. Kingshuk Mukhuti Dr. V. N. K. B. Adusumalli Mr. Heramba V. S. R. M. Koppisetti Prof. Bhavtosh Bansal Prof. Venkataramanan Mahalingam 《Chemphyschem》2020,21(15):1731-1736
Precise assessment of temperature is crucial in many physical, technological, and biological applications where optical thermometry has attracted considerable attention primarily due to fast response, contactless measurement route, and electromagnetic passivity. Rare-earth-doped thermographic phosphors that rely on ratiometric sensing are very efficient near and above room temperature. However, being dependent on the thermally-assisted migration of carriers to higher excited states, they are largely limited by the quenching of the activation mechanism at low temperatures. In this paper, we demonstrate a strategy to pass through this bottleneck by designing a linear colorimetric thermometer by which we could estimate down to 4 K. The change in perceptual color fidelity metric provides an accurate measure for the sensitivity of the thermometer that attains a maximum value of 0.86 K−1. Thermally coupled states in Er3+ are also used as a ratiometric sensor from room temperature to ∼140 K. The results obtained in this work clearly show that Yb3+−Er3+ co-doped NaGdF4 microcrystals are a promising system that enables reliable bimodal thermometry in a very wide temperature range from ultralow (4 K) to ambient (290 K) conditions. 相似文献
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Polymer electrolyte films prepared from poly (methyl methacrylate) and LiAsF6 with different concentrations of plasticizer (DBP) are described. The formation of polymer-salt complexes has been confirmed
by XRD and FTIR spectral studies. The temperature dependence of the conductivity of the polymer films obeys the VTF relation.
Values of conductivities of the polymer complexes are presented and discussed. 相似文献
9.
This paper deals with the propagation of solitons in real fibres, governed by the system of inhomogeneous nonlinear Schrödinger (INLS) equations. The Painlevé singularity structure analysis is utilized to check for the integrability of the system and from the analysis, the system is found to admit soliton-type lossless wave propagation. The system is transformed to its homogeneous counterpart using a suitable variable transformation and the soliton solutions are obtained through Bäcklund transformation after constructing the explicit Lax pair for the system. The one-soliton solutions are plotted for different choices of inhomogeneity parameters and the evolutionary characteristics of the solutions are analyzed. 相似文献
10.
Donghan Kim Sun-Ho Kang Mahalingam Balasubramanian Christopher S. Johnson 《Electrochemistry communications》2010,12(11):1618-1621
A lithium-rich nickel-manganese oxide compound Lix(Ni0.25Mn0.75)Oy (x > 1) was synthesized from layered Na0.9Li0.3Ni0.25Mn0.75Oδ precursor using a lithium ion-exchange reaction. The electrochemical behavior of the material as a cathode for lithium batteries, and a preliminary discussion of its structure are reported. The product Li1.32Na0.02Ni0.25Mn0.75Oy (IE-LNMO) shows broad X-ray diffraction peaks, but possesses a high intensity sharp (003) layering peak and multiple peaks with intensity in the 20–23° 2θ region which suggest Ni–Mn ordering in the transition metal layer (TM). Li/IE-LNMO cells demonstrate very stable reversible capacities of 220 mAh/g @ 15 mA/g and possess extremely high power of 150 mAh/g @ 1500 mA/g (15C). The Li/IE-LNMO cell dQ/dV plot exhibits three reversible electrochemical processes due to Ni/Mn redox behavior in a layered component, and Mn redox exchange in a spinel component. No alteration in the dQ/dV curves and no detectable change in the voltage profiles over 40 cycles were observed, thus indicating a stable structure for lithium insertion/extraction. This new material is attractive for demanding Li-ion battery applications. 相似文献