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排序方式: 共有198条查询结果,搜索用时 359 毫秒
41.
Ghosh Bidisha Roy Shubham Bardhan Souravi Mondal Dhananjoy Saha Ishita Ghosh Saheli Basu Ruma Karmakar Parimal Das Kaustuv Das Sukhen 《Journal of fluorescence》2022,32(4):1489-1500
Journal of Fluorescence - This article reports the fluorometric detection of toxic hexavalent chromium Cr (VI)) in wastewater and Cr (VI) contaminated living cells using in-situ grown carbon... 相似文献
42.
Thaker HD Som A Ayaz F Lui D Pan W Scott RW Anguita J Tew GN 《Journal of the American Chemical Society》2012,134(27):11088-11091
A new series of aryl-based synthetic mimics of antimicrobial peptides (SMAMPs) with antimicrobial activity and selectivity have been developed via systematic tuning of the aromatic groups and charge. The addition of a pendant aromatic group improved the antimicrobial activity against Gram-negative bacteria, while the addition of charge improved the selectivity. SMAMP 4 with six charges and a naphthalene central ring demonstrated a selectivity of 200 against both Staphylococcus aureus and Escherichia coli , compared with a selectivity of 8 for the peptide MSI-78. In addition to the direct antimicrobial activity, SMAMP 4 exhibited specific immunomodulatory activities in macrophages both in the presence and in the absence of lipopolysaccharide, a TLR agonist. SMAMP 4 also induced the production of a neutrophil chemoattractant, murine KC, in mouse primary cells. This is the first nonpeptidic SMAMP demonstrating both good antimicrobial and immunomodulatory activities. 相似文献
43.
Numerical simulation of exciton dynamics in Cu(2)O at ultra-low temperatures within a potential trap
We have studied theoretically the relaxation behaviour of excitons in cuprous oxide (Cu(2)O) at ultra-low temperatures when excitons are confined within a potential trap by solving numerically the Boltzmann equation. As relaxation processes, we have included in this paper deformation potential phonon scattering, radiative and non-radiative decay and Auger decay. The relaxation kinetics has been analysed for temperatures in the range between 0.3 and 5?K. Under the action of deformation potential phonon scattering only, we find for temperatures above 0.5?K that the excitons reach local equilibrium with the lattice, i.e.?that the effective local temperature is coming down to the bath temperature, while below 0.5?K a non-thermal energy distribution remains. Interestingly, for all temperatures the global spatial distribution of excitons does not reach the equilibrium distribution, but stays at a much higher effective temperature. If we include further a finite lifetime of the excitons and the two-particle Auger decay, we find that both the local and the global effective temperature do not come down to the bath temperature. In the first case we find that a Bose-Einstein condensation (BEC) occurs for all temperatures in the investigated range. Comparing our results with the thermal equilibrium case, we find that BEC occurs for a significantly higher number of excitons in the trap. This effect could be related to the higher global temperature, which requires an increased number of excitons within the trap to observe the BEC. In the case of Auger decay, we do not find a BEC at any temperature due to the local heating of the exciton gas. 相似文献
44.
Building activities are recognised to produce coarse particulate matter but less is known about the release of airborne ultrafine
particles (UFPs; those below 100 nm in diameter). For the first time, this study has investigated the release of particles
in the 5–560 nm range from three simulated building activities: the crushing of concrete cubes, the demolition of old concrete
slabs, and the recycling of concrete debris. A fast response differential mobility spectrometer (Cambustion DMS50) was used
to measure particle number concentrations (PNC) and size distributions (PNDs) at a sampling frequency of 10 Hz in a confined
laboratory room providing controlled environment and near–steady background PNCs. The sampling point was intentionally kept
close to the test samples so that the release of new UFPs during these simulated processes can be quantified. Tri–modal particle
size distributions were recorded for all cases, demonstrating different peak diameters in fresh nuclei (<10 nm), nucleation
(10–30 nm) and accumulation (30–300 nm) modes for individual activities. The measured background size distributions showed
modal peaks at about 13 and 49 nm with average background PNCs ~1.47 × 104 cm−3. These background modal peaks shifted towards the larger sizes during the work periods (i.e. actual experiments) and the
total PNCs increased between 2 and 17 times over the background PNCs for different activities. After adjusting for background
concentrations, the net release of PNCs during cube crushing, slab demolition, and ‘dry’ and ‘wet’ recycling events were measured
as ~0.77, 19.1, 22.7 and 1.76 (×104) cm−3, respectively. The PNDs were converted into particle mass concentrations (PMCs). While majority of new PNC release was below
100 nm (i.e. UFPs), the bulk of new PMC emissions were constituted by the particles over 100 nm; ~95, 79, 73 and 90% of total
PNCs, and ~71, 92, 93 and 91% of total PMCs, for cube crushing, slab demolition, dry recycling and wet recycling, respectively.
The results of this study firmly elucidate the release of UFPs and raise a need for further detailed studies and designing
health and safety related exposure guidelines for laboratory workplaces and operational building sites. 相似文献
45.
Dr. Ramadoss Govindarajan Shubham Deolka Dr. Eugene Khaskin Dr. Robert R. Fayzullin Dr. Shrinwantu Pal Dr. Serhii Vasylevskyi Prof. Julia R. Khusnutdinova 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(44):e202201639
We report a series of heterobimetallic Pt/Zn and Pt/Ca complexes to study the effect of proximity of a dicationic base metal on the organometallic Pt species. Varying degrees of Pt⋅⋅⋅Zn and Zn interaction with the bridging Me group are achieved, showcasing snapshots of a hypothetical process of retrotransmetalation from Pt to Zn. In contrast, only weak interactions were observed for Ca with a Pt-bound Me group. Activation of H2, B−H and Si−H bonds leads to the formation of hydride-bridged Pt−H−Zn complexes, which is not observed in the absence of Zn, pointing out the importance of metal-metal cooperation. Reactivity of PtMe2/M2+ with terminal acetylene, water and methanol is also studied, leading to facile protonation of one of the Me groups at the Pt center only when Zn is present. This study sheds light on various ways in which the presence of a 2+ metal cation significantly affects the reactivity of a common organoplatinum complex. 相似文献
46.
Jacques kagan Katrina Tadema-Wielandt Ging Chan Som N. Dhawan Jeffrey Jaworsky Indra Prakash Sudershan K. Arora 《Photochemistry and photobiology》1984,39(4):465-467
Abstract— Phenylheptatriyne (PHT) is a good singlet oxygen sensitizer in vitro. In vivo , its phototoxicity toward E. coli B has been proved unequivocally to depend on the presence of oxygen. The literature reports indicating that phenylheptatriyne was representative of a new class of sensitizers were probably based on experiments conducted under conditions which were not strictly anaerobic. 相似文献
47.
We give the extra condition necessary to propagate Einstein's equations from a space-like hypersurface into space-time with quasi-maxwellian equations. 相似文献
48.
49.
The Brans-Dicke (BD) theory admits de Sitter spacetime as a solution with an equation of statep=1/3 when the coupling constant of the BD theory is –3/2. 相似文献
50.