661 research outputs found
Optimizations of sub-100 nm Si/SiGe MODFETs for high linearity RF applications
Based on careful calibration in respect of 70 nm n-type strained Si channel S/SiGe modulation doped FETs (MODFETs) fabricated by Daimler Chrysler, numerical simulations have been used to study the impact of the device geometry and various doping strategies on device performance and linearity. The device geometry is sensitive to both RF performance and device linearity. Doped channel devices are found to be promising for high linearity applications. Trade-off design strategies are required for reconciling the demands of high device performance and high linearity simultaneously. The simulations also suggest that gate length scaling helps to achieve higher RF performance, but decreases the linearity
Antibiotic Therapy, Endotoxin Concentration in Cerebrospinal Fluid, and Brain Edema in Experimental Escherichia coli Meningitis in Rabbits
We investigated the effect of cefotaxime and chloramphenicol on endotoxin concentrations in cerebrospinal fluid (CSF) and on the development of brain edema in rabbits with Escherichia coli meningitis. Both antibiotics were similarly effective in reducing bacterial titers. Cefotaxime, but not chloramphenicol, induced a marked increase of endotoxin in CSF, from log10 1.5 ± 0.8 to log10 2.8 ± 0.7 ng/ml (P < .01). This result was associated with an increase in brain water content (405 ± 12 g of water/100 g of dry weight compared with 389 ± 8 g in untreated controls; P < .01), whereas in animals treated with chloramphenicol, brain water content was identical to controls. The cefotaxime-induced increase in endotoxin concentration and brain edema were both neutralized by polymyxin B, which binds to the lipid A moiety of endotoxin, or by a monoclonal antibody to lipid A. These results indicate that treating gram-negative bacillary meningitis with selected antibiotics induces increased endotoxin concentrations in CSF that are associated with brain edem
Dicianodiamida (DCD) diminui emissĂŁo de N2O de solo incubado com diferentes nĂveis de palha de cana-de-açĂșcar e N mineral.
Resumo ? A aplicação de inibidores de nitrificação tem sido difundida como ferramenta na mitigação das emissĂ”es de Ăłxido nitroso (N2O). Maiores benefĂcios poderĂŁo ser encontrados em ĂĄreas com manutenção de resĂduos, como a palha da cana, os quais podem contribuir com formas solĂșveis de carbono. O objetivo deste estudo foi testar em condiçÔes controladas o efeito da dicianodiamida (DCD) nas emissĂ”es de N2O a partir de um solo incubado com diferentes doses de palha de cana e N mineral. Os tratamentos resultaram da combinação de trĂȘs doses de palha equivalentes a 0, 8 e 16 Mg MS ha-1, dois nĂveis de N mineral equivalentes a 0 e 100 kg de N ha-1 e dois nĂveis de DCD: com e sem DCD. Ao longo de 120 dias de incubação foram realizadas 42 amostragens para determinação da quantidade acumulada de N2O. O uso de N aumentou a emissĂŁo de N2O em relação aos controles, independente da dose de palha aplicada. Por outro lado, o uso de DCD foi capaz de reduzir as perdas desse gĂĄs em mais de 60% para todas as doses de palha, em relação aos tratamentos com N e sem DCD. Quando N foi adicionado, a maior dose de palha aumentou a emissĂŁo em relação ao tratamento sem resĂduo. O efeito da palha Ă© atribuĂdo ao aumento da concentração de carbono orgĂąnico dissolvido na camada superficial. A palha de cana exerce um efeito sinergĂ©tico Ă aplicação de N em relação Ă s emissĂ”es de N2O, porĂ©m o DCD Ă© eficiente em reduzir essas perdas
Ciprofioxacin in experimental Pseudomonas aeruginosa meningitis in rabbits
The potential of ciprofloxacin for the therapy of Pseudomonas aeruginosa meningitis was evaluated in an animal model by determining the penetration of the drug into CSF, its concentration-dependent killing characteristics in vivo, and its relative efficacy compared with ceftazidime and tobramycin. Meningitis was produced in 40 rabbits by intracisternal injection of 3 x 10 7 organisms. The drugs were administered intravenously over seven hours, and simultaneous serum and CSF samples were taken at 0, 1, 3, 5, and 7 h for determination of drug concentration and CSF bacterial counts. The percentage penetration of ciprofloxacin (18-4± 12'3; mean±standard deviation) in infected rabbits was substantially increased over that found in uninfected rabbits (4'1 ± 1· 3). The rate of bacterial killing for animals treated with ceftazidime (100 mg/kg/h) and high doses of tobramycin (2·5 mg/kg/h) was -0·51 ±0·13 (lOglO cfu/ml/h). This was similar to the rate of killing (-0-48±0·2) found when ciprofloxacin was infused at 5 mg/kg/h, a dose that produced a mean serum level of 6·7 ± 4·6 mg/I, which corresponds to concentrations achievable in humans. As dosages were increased (15 and 30 mg/kg/h), the rate of bacterial killing also increased (-0'70 ±O'I and -0·89±0·4 respectively; r = 0·7407; P<O·OI). The drug shows promise in the treatment of pseudomonas meningitis
Impact of Public Charging Infrastructure on the Adoption of Electric Vehicles in London
The discussion on the importance of public charging infrastructure is usually framed around the âchicken-eggâ challenge of consumers feeling reluctant to purchase without the necessary infrastructure and policy makers reluctant to invest in the infrastructure without the demand. However, public charging infrastructure may be more crucial to EV adoption than previously thought.
Historically, access to residential charging was thought to be a major factor in potential for growth in the EV market as it offered a guaranteed place for a vehicle to be charged. However, these conclusions were reached through studies conducted in regions with a high percentage of homes that have access to residential parking.
The purpose of this study is to understand how the built environment may encourage uptake of EVs by seeking a correlation between EV ownership and public charging points in an urban and densely populated city such as London.
Using a statistical approach with data from the Department for Transport and Zap Map, a statistically significant correlation was found between the total (slow, fast and rapid) number of public charging points and number of EV registrations per boroughâwith the strongest correlation found between EV registrations and rapid chargers.
This research does not explicitly prove that there is a cause-and-effect relationship between public charging points EVs but challenges some of the previous literature which indicates that public charging infrastructure is not as important as home charging. The study also supports the notion that the built environment can influence human behaviour
Diffusive and Ballistic Transport in Ultra-thin InSb Nanowire Devices Using a Few-layer-Graphene-AlOx Gate
Quantum devices based on InSb nanowires (NWs) are a prime candidate system
for realizing and exploring topologically-protected quantum states and for
electrically-controlled spin-based qubits. The influence of disorder on
achieving reliable topological regimes has been studied theoretically,
highlighting the importance of optimizing both growth and nanofabrication. In
this work we investigate both aspects. We developed InSb nanowires with
ultra-thin diameters, as well as a new gating approach, involving few-layer
graphene (FLG) and Atomic Layer Deposition (ALD)-grown AlOx. Low-temperature
electronic transport measurements of these devices reveal conductance plateaus
and Fabry-P\'erot interference, evidencing phase-coherent transport in the
regime of few quantum modes. The approaches developed in this work could help
mitigate the role of material and fabrication-induced disorder in
semiconductor-based quantum devices.Comment: 14 pages, 5 figure
Improved efficacy of ciprofloxacin administered in polyethylene glycol-coated liposomes for treatment of Klebsiella pneumoniae pneumonia in rats.
Animal and clinical data show that high ratios of the area under the
concentration-time curve and the peak concentration in blood to the MIC of
fluoroquinolones for a given pathogen are associated with a favorable
outcome. The present study investigated whether improvement of the
therapeutic potential of ciprofloxacin could be achieved by encapsulation
in polyethylene glycol (PEG)-coated long-circulating sustained-release
liposomes. In a rat model of unilateral Klebsiella pneumoniae pneumonia
(MIC = 0.1 microg/ml), antibiotic was administered at 12- or 24-h
intervals at twofold-increasing doses. A treatment period of 3 days was
started 24 h after inoculation of the left lung, when the bacterial count
had increased 1,000-fold and some rats had positive blood cultures. The
infection was fatal within 5 days in untreated rats. Administration of
ciprofloxacin in the liposomal form resulted in delayed ciprofloxacin
clearance and increased and prolonged ciprofloxacin concentrations in
blood and tissues. The ED(50) (dosage that results in 50% survival) of
liposomal ciprofloxacin was 3.3 mg/kg of body weight/day given once daily,
and that of free ciprofloxacin was 18.9 mg/kg/day once daily or 5.1
mg/kg/day twice daily. The ED(90) of liposomal ciprofloxacin was 15.0
mg/kg/day once daily compared with 36.0 mg/kg/day twice daily for free
ciprofloxacin; 90% survival could not be achieved with free ciprofloxacin
given once daily. In summary, the therapeutic efficacy of liposomal
ciprofloxacin was superior to that of ciprofloxacin in the free form.
PEG-coated liposomal ciprofloxacin was well tolerated in relatively high
doses, permitting once daily administration with relatively low
ciprofloxacin clearance and without compromising therapeutic efficacy
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