236 research outputs found
Log-normal distributions of suspended particles in the open ocean
A scanning electron microscope-electron microprobe technique was used to chemically distinguish and size particles as fine as 0.2/µm on GEOSECS suspended matter filters from the open ocean…
Prediction of Graft-Versus-Host Disease in Humans by Donor Gene-Expression Profiling
BACKGROUND: Graft-versus-host disease (GVHD) results from recognition of host antigens by donor T cells following allogeneic hematopoietic cell transplantation (AHCT). Notably, histoincompatibility between donor and recipient is necessary but not sufficient to elicit GVHD. Therefore, we tested the hypothesis that some donors may be “stronger alloresponders” than others, and consequently more likely to elicit GVHD. METHODS AND FINDINGS: To this end, we measured the gene-expression profiles of CD4(+) and CD8(+) T cells from 50 AHCT donors with microarrays. We report that pre-AHCT gene-expression profiling segregates donors whose recipient suffered from GVHD or not. Using quantitative PCR, established statistical tests, and analysis of multiple independent training-test datasets, we found that for chronic GVHD the “dangerous donor” trait (occurrence of GVHD in the recipient) is under polygenic control and is shaped by the activity of genes that regulate transforming growth factor-β signaling and cell proliferation. CONCLUSIONS: These findings strongly suggest that the donor gene-expression profile has a dominant influence on the occurrence of GVHD in the recipient. The ability to discriminate strong and weak alloresponders using gene-expression profiling could pave the way to personalized transplantation medicine
Solar Carbon Monoxide, Thermal Profiling, and the Abundances of C, O, and their Isotopes
A solar photospheric "thermal profiling" analysis is presented, exploiting
the infrared rovibrational bands of carbon monoxide (CO) as observed with the
McMath-Pierce Fourier transform spectrometer (FTS) at Kitt Peak, and from above
the Earth's atmosphere by the Shuttle-borne ATMOS experiment. Visible continuum
intensities and center-limb behavior constrained the temperature profile of the
deep photosphere, while CO center-limb behavior defined the thermal structure
at higher altitudes. The oxygen abundance was self consistently determined from
weak CO absorptions. Our analysis was meant to complement recent studies based
on 3-D convection models which, among other things, have revised the historical
solar oxygen (and carbon) abundance downward by a factor of nearly two;
although in fact our conclusions do not support such a revision. Based on
various considerations, an oxygen abundance of 700+/-100 ppm (parts per million
relative to hydrogen) is recommended; the large uncertainty reflects the model
sensitivity of CO. New solar isotopic ratios also are reported for 13C, 17O,
and 18O.Comment: 90 pages, 19 figures (some with parts "a", "b", etc.); to be
published in the Astrophysical Journal Supplement
STRUCTURAL-MECHANICS ANALYSIS OF THE 10G TRANSFORMER IMPACT
Transportation of the power transformers from the site of production to the site of the exploitation
is very complex and sensible task. During transportation, the transformer can be subjected to a variety of
different impacts registered either during railway transportation or during on/off loading. The transformer
should be designed to sustain the high accelerations appearing often during transportation.
Transformer are usually equipped with the impact recorder to registry the acceleration behavior
during the transport. In the current paper, we give an overview on the structural-mechanics analysis of
10g impact on the power transformer registered during the railway transportation of the transformer from
Canada to US
Combined Characterisation of GOME and TOMS Total Ozone Using Ground-Based Observations from the NDSC
Several years of total ozone measured from space by the ERS-2 GOME, the Earth Probe Total Ozone Mapping Spectrometer (TOMS), and the ADEOS TOMS, are compared with high-quality ground-based observations associated with the Network for the Detection of Stratospheric Change (NDSC), over an extended latitude range and a variety of geophysical conditions. The comparisons with each spaceborne sensor are combined altogether for investigating their respective solar zenith angle (SZA) dependence, dispersion, and difference of sensitivity. The space- and ground-based data are found to agree within a few percent on average. However, the analysis highlights for both Global Ozone Monitoring Experiment (GOME) and TOMS several sources of discrepancies, including a dependence on the SZA at high latitudes and internal inconsistencies
Recommended from our members
The global diet and activity research (GDAR) network: a global public health partnership to address upstream NCD risk factors in urban low and middle-income contexts.
BACKGROUND: Non-communicable diseases (NCDs) are the leading cause of death globally. While upstream approaches to tackle NCD risk factors of poor quality diets and physical inactivity have been trialled in high income countries (HICs), there is little evidence from low and middle-income countries (LMICs) that bear a disproportionate NCD burden. Sub-Saharan Africa and the Caribbean are therefore the focus regions for a novel global health partnership to address upstream determinants of NCDs. PARTNERSHIP: The Global Diet and Activity research Network (GDAR Network) was formed in July 2017 with funding from the UK National Institute for Health Research (NIHR) Global Health Research Units and Groups Programme. We describe the GDAR Network as a case example and a potential model for research generation and capacity strengthening for others committed to addressing the upstream determinants of NCDs in LMICs. We highlight the dual equity targets of research generation and capacity strengthening in the description of the four work packages. The work packages focus on learning from the past through identifying evidence and policy gaps and priorities, understanding the present through adolescent lived experiences of healthy eating and physical activity, and co-designing future interventions with non-academic stakeholders. CONCLUSION: We present five lessons learned to date from the GDAR Network activities that can benefit other global health research partnerships. We close with a summary of the GDAR Network contribution to cultivating sustainable capacity strengthening and cutting-edge policy-relevant research as a beacon to exemplify the need for such collaborative groups
Early-onset ventilator-associated pneumonia incidence in intensive care units: a surveillance-based study
ABSTRACT: BACKGROUND: The incidence of ventilator-associated pneumonia (VAP) within the first 48 hours of intensive care unit (ICU) stay has been poorly investigated. The objective was to estimate early-onset VAP occurrence in ICUs within 48 hours after admission. METHODS: We analyzed data from prospective surveillance between 01/01/2001 and 31/12/2009 in 11 ICUs of Lyon hospitals (France). The inclusion criteria were: first ICU admission, not hospitalized before admission, invasive mechanical ventilation during first ICU day, free of antibiotics at admission, and ICU stay >=48 hours. VAP was defined according to a national protocol. Its incidence was the number of events per 1,000 invasive mechanical ventilation-days. The Poisson regression model was fitted from day 2 (D2) to D8 to incident VAP to estimate the expected VAP incidence from D0 to D1 of ICU stay. RESULTS: Totally, 367 (10.8%) of 3,387 patients in 45,760 patient-days developed VAP within the first 9 days. The predicted cumulative VAP incidence at D0 and D1 was 5.3 (2.6-9.8) and 8.3 (6.1-11.1), respectively. The predicted cumulative VAP incidence was 23.0 (20.8-25.3) at D8. The proportion of missed VAP within 48 hours from admission was 11% (9%-17%). CONCLUSIONS: Our study indicates underestimation of early-onset VAP incidence in ICUs, if only VAP occurring [greater than or equal to]48 hours is considered to be hospital-acquired. Clinicians should be encouraged to develop a strategy for early detection after ICU admission
Le Forum, Vol. 44 #3
https://digitalcommons.library.umaine.edu/francoamericain_forum/1105/thumbnail.jp
The Homeodomain Derived Peptide Penetratin Induces Curvature of Fluid Membrane Domains
BACKGROUND:Protein membrane transduction domains that are able to cross the plasma membrane are present in several transcription factors, such as the homeodomain proteins and the viral proteins such as Tat of HIV-1. Their discovery resulted in both new concepts on the cell communication during development, and the conception of cell penetrating peptide vectors for internalisation of active molecules into cells. A promising cell penetrating peptide is Penetratin, which crosses the cell membranes by a receptor and metabolic energy-independent mechanism. Recent works have claimed that Penetratin and similar peptides are internalized by endocytosis, but other endocytosis-independent mechanisms have been proposed. Endosomes or plasma membranes crossing mechanisms are not well understood. Previously, we have shown that basic peptides induce membrane invaginations suggesting a new mechanism for uptake, "physical endocytosis". METHODOLOGY/PRINCIPAL FINDINGS:Herein, we investigate the role of membrane lipid phases on Penetratin induced membrane deformations (liquid ordered such as in "raft" microdomains versus disordered fluid "non-raft" domains) in membrane models. Experimental data show that zwitterionic lipid headgroups take part in the interaction with Penetratin suggesting that the external leaflet lipids of cells plasma membrane are competent for peptide interaction in the absence of net negative charges. NMR and X-ray diffraction data show that the membrane perturbations (tubulation and vesiculation) are associated with an increase in membrane negative curvature. These effects on curvature were observed in the liquid disordered but not in the liquid ordered (raft-like) membrane domains. CONCLUSIONS/SIGNIFICANCE:The better understanding of the internalisation mechanisms of protein transduction domains will help both the understanding of the mechanisms of cell communication and the development of potential therapeutic molecular vectors. Here we showed that the membrane targets for these molecules are preferentially the fluid membrane domains and that the mechanism involves the induction of membrane negative curvature. Consequences on cellular uptake are discussed
- …