191 research outputs found
Non-invasive respiratory support in the management of acute COVID-19 pneumonia: considerations for clinical practice and priorities for research
Non-invasive respiratory support (NIRS) has increasingly been used in the management of COVID-19-associated acute respiratory failure, but questions remain about the utility, safety, and outcome benefit of NIRS strategies. We identified two randomised controlled trials and 83 observational studies, compromising 13 931 patients, that examined the effects of NIRS modalities-high-flow nasal oxygen, continuous positive airway pressure, and bilevel positive airway pressure-on patients with COVID-19. Of 5120 patients who were candidates for full treatment escalation, 1880 (37%) progressed to invasive mechanical ventilation and 3658 of 4669 (78%) survived to study end. Survival was 30% among the 1050 patients for whom NIRS was the stated ceiling of treatment. The two randomised controlled trials indicate superiority of non-invasive ventilation over high-flow nasal oxygen in reducing the need for intubation. Reported complication rates were low. Overall, the studies indicate that NIRS in patients with COVID-19 is safe, improves resource utilisation, and might be associated with better outcomes. To guide clinical decision making, prospective, randomised studies are needed to address timing of intervention, optimal use of NIRS modalities-alone or in combination-and validation of tools such as oxygenation indices, response to a trial of NIRS, and inflammatory markers as predictors of treatment success
Quantum Critical Scaling in a Moderately Doped Antiferromagnet
Using high temperature expansions for the equal time correlator and
static susceptibility for the t-J model, we present evidence for
quantum critical (QC), , behavior at intermediate temperatures in a
broad range of ratio, doping, and temperatures. We find that the
dynamical susceptibility is very close to the universal scaling function
computable for the asymptotic QC regime, and that the dominant energy scale is
temperature. Our results are in excellent agreement with measurements of the
spin-echo decay rate, , in LaCuO, and provide qualitative
understanding of both and nuclear relaxation rates in
doped cuprates.Comment: 11 pages, REVTeX v3.0, PostScript file for 3 figures is attached,
UIUC-P-93-07-068. In this revised version, we calculate the scaling functions
and thus present new and more direct evidence in favor of our original
conclusion
Scaling Regimes, Crossovers, and Lattice Corrections in 2D Heisenberg Antiferromagnets
We study scaling behavior in 2D, S=1/2 and S=1 Heisenberg antiferromagnets
using the data on full q-dependences of the equal time structure factor and the
static susceptibility, calculated through high temperature expansions. We also
carry out comparisons with a model of two coupled S=1/2 planes with the
interlayer coupling tuned to the T=0 critical point. We separately determine
the spin-wave velocity c and mass , in addition to the correlation
length, , and find that c is temperature dependent; only for T\alt JS,
it approaches its known T=0 value . Despite this temperature dependent
spin-wave velocity, full q- and -dependences of the dynamical
susceptibility agree with the universal scaling functions
computable for the -model, for temperatures upto .
Detailed comparisons show that below the S=1 model is in the renormalized
classical (RC) regime, the two plane model is in the quantum critical (QC)
regime, and the S=1/2 model exhibits a RC-QC crossover, centered at T=0.55J. In
particular, for the S=1/2 model above this crossover and for the two-plane
model at all T, the spin-wave mass is in excellent agreement with the universal
QC prediction, . In contrast, for the S=1/2 model below the
RC-QC crossover, and for the S=1 model at all T, the behavior agrees with the
known RC expression. For all models nonuniversal behavior occurs above . Our results strongly support the conjecture of Chubukov and Sachdev
that the S=1/2 model is close to the T=0 critical point to exhibit QC behavior.Comment: 13 pages, REVTeX with attached PostScript (see file for addl info
Mutation at the Evi1 locus in Junbo mice causes susceptibility to otitis media
Otitis media ( OM), inflammation of the middle ear, remains the most common cause of hearing impairment in children. It is also the most common cause of surgery in children in the developed world. There is evidence from studies of the human population and mouse models that there is a significant genetic component predisposing to OM, yet nothing is known about the underlying genetic pathways involved in humans. We identified an N-ethyl-N-nitrosourea-induced dominant mouse mutant Junbo with hearing loss due to chronic suppurative OM and otorrhea. This develops from acute OM that arises spontaneously in the postnatal period, with the age of onset and early severity dependent on the microbiological status of the mice and their air quality. We have identified the causal mutation, a missense change in the C-terminal zinc finger region of the transcription factor Evi1. This protein is expressed in middle ear basal epithelial cells, fibroblasts, and neutrophil leukocytes at postnatal day 13 and 21 when inflammatory changes are underway. The identification and characterization of the Junbo mutant elaborates a novel role for Evi1 in mammalian disease and implicates a new pathway in genetic predisposition to OM
Spin Gaps and Bilayer Coupling in YBaCuO and YBaCuO
We investigate the relevance to the physics of underdoped
YBaCuO and YBaCuO of the quantum critical point
which occurs in a model of two antiferromagnetically coupled planes of
antiferromagnetically correlated spins. We use a Schwinger boson mean field
theory and a scaling analysis to obtain the phase diagram of the model and the
temperature and frequency dependence of various susceptibilities and relaxation
rates. We distinguish between a low coupled-planes regime in which
the optic spin excitations are frozen out and a high
decoupled-planes regime in which the two planes fluctuate independently. In the
coupled-planes regime the yttrium nuclear relaxation rate at low temperatures
is larger relative to the copper and oxygen rates than would be naively
expected in a model of uncorrelated planes. Available data suggest that in
YBaCuO the crossover from the coupled to the decoupled planes
regime occurs at or . The predicted correlation length is
of order 6 lattice constants at . Experimental data related to the
antiferromagnetic susceptibility of YBaCuO may be made consistent
with the theory, but available data for the uniform susceptibility are
inconsistent with the theory.Comment: RevTex 3.
A dominant mutation within the DNA-binding domain of the bZIP transcription factor Maf causes murine cataract and results in selective alteration in DNA binding
The murine autosomal dominant cataract mutants created in mutagenesis experiments have proven to be a powerful resource for modelling the biological processes involved in cataractogenesis. We report a mutant which in the heterozygous state exhibits mild pulverulent cataract named 'opaque flecks in lens', symbol Ofl. By molecular mapping, followed by a candidate gene approach, the mutant was shown to be allelic with a knockout of the bZIP transcription factor, Maf. Homozygotes for Ofl and for Maf null mutations are similar but a new effect, renal tubular nephritis, was found in Ofl homozygotes surviving beyond 4 weeks, which may contribute to early lethality. Sequencing identified the mutation as a G-->A change, leading to the amino-acid substitution mutation R291Q in the basic region of the DNA-binding domain. Since mice heterozygous for knockouts of Maf show no cataracts, this suggests that the Ofl R291Q mutant protein has a dominant effect. We have demonstrated that this mutation results in a selective alteration in DNA binding affinities to target oligonucleotides containing variations in the core CRE and TRE elements. This implies that arginine 291 is important for core element binding and suggests that the mutant protein may exert a differential downstream effect amongst its binding targets. The cataracts seen in Ofl heterozygotes and human MAF mutations are similar to one another, implying that Ofl may be a model of human pulverulent cortical cataract. Furthermore, when bred onto a different genetic background Ofl heterozygotes also show anterior segment abnormalities. The Ofl mutant therefore provides a valuable model system for the study of Maf, and its interacting factors, in normal and abnormal lens and anterior segment development
Agreement among Health Care Professionals in Diagnosing Case Vignette-Based Surgical Site Infections
OBJECTIVE: To assess agreement in diagnosing surgical site infection (SSI) among healthcare professionals involved in SSI surveillance. METHODS: Case-vignette study done in 2009 in 140 healthcare professionals from seven specialties (20 in each specialty, Anesthesiologists, Surgeons, Public health specialists, Infection control physicians, Infection control nurses, Infectious diseases specialists, Microbiologists) in 29 University and 36 non-University hospitals in France. We developed 40 case-vignettes based on cardiac and gastrointestinal surgery patients with suspected SSI. Each participant scored six randomly assigned case-vignettes before and after reading the SSI definition on an online secure relational database. The intraclass correlation coefficient (ICC) was used to assess agreement regarding SSI diagnosis on a seven-point Likert scale and the kappa coefficient to assess agreement for superficial or deep SSI on a three-point scale. RESULTS: Based on a consensus, SSI was present in 21 of 40 vignettes (52.5%). Intraspecialty agreement for SSI diagnosis ranged across specialties from 0.15 (95% confidence interval, 0.00-0.59) (anesthesiologists and infection control nurses) to 0.73 (0.32-0.90) (infectious diseases specialists). Reading the SSI definition improved agreement in the specialties with poor initial agreement. Intraspecialty agreement for superficial or deep SSI ranged from 0.10 (-0.19-0.38) to 0.54 (0.25-0.83) (surgeons) and increased after reading the SSI definition only among the infection control nurses from 0.10 (-0.19-0.38) to 0.41 (-0.09-0.72). Interspecialty agreement for SSI diagnosis was 0.36 (0.22-0.54) and increased to 0.47 (0.31-0.64) after reading the SSI definition. CONCLUSION: Among healthcare professionals evaluating case-vignettes for possible surgical site infection, there was large disagreement in diagnosis that varied both between and within specialties
Life Cycle-Dependent Cytoskeletal Modifications in Plasmodium falciparum Infected Erythrocytes
10.1371/journal.pone.0061170PLoS ONE84
PRIMO: an interactive homology modeling pipeline
The development of automated servers to predict the three-dimensional structure of proteins has seen much progress over the years. These servers make calculations simpler, but largely exclude users from the process. In this study, we present the PRotein Interactive MOdeling (PRIMO) pipeline for homology modeling of protein monomers. The pipeline eases the multi-step modeling process, and reduces the workload required by the user, while still allowing engagement from the user during every step. Default parameters are given for each step, which can either be modified or supplemented with additional external input. PRIMO has been designed for users of varying levels of experience with homology modeling. The pipeline incorporates a user-friendly interface that makes it easy to alter parameters used during modeling
- …