650 research outputs found
Comparing the acute sensitivity of growth and photosynthetic endpoints in three Lemna species exposed to four herbicides
Scanning tunneling microscopy and spectroscopy at low temperatures of the (110) surface of Te doped GaAs single crystals
We have performed voltage dependent imaging and spatially resolved
spectroscopy on the (110) surface of Te doped GaAs single crystals with a low
temperature scanning tunneling microscope (STM). A large fraction of the
observed defects are identified as Te dopant atoms which can be observed down
to the fifth subsurface layer. For negative sample voltages, the dopant atoms
are surrounded by Friedel charge density oscillations. Spatially resolved
spectroscopy above the dopant atoms and above defect free areas of the GaAs
(110) surface reveals the presence of conductance peaks inside the
semiconductor band gap. The appearance of the peaks can be linked to charges
residing on states which are localized within the tunnel junction area. We show
that these localized states can be present on the doped GaAs surface as well as
at the STM tip apex.Comment: 8 pages, 8 figures, accepted for publication in PR
Long-term outcome and health-related quality of life in difficult-to-wean patients with and without ventilator dependency at ICU discharge : a retrospective cohort study
Background: Long-term outcome and quality of life (QOL) in patients requiring prolonged mechanical ventilation after failure to wean in the ICU is scarcely documented. We aimed to evaluate long-term survival and QOL in patients discharged from the ICU with a tracheostomy for difficult weaning, and with or without ventilator dependency at ICU discharge.
Methods: We retrospectively investigated post-ICU trajectories and survival in patients requiring tracheostomy for difficult weaning admitted to the medical ICU of a tertiary center between 1999 and 2013, discriminating between patients who were ventilator dependent or were weaned at ICU discharge. In 2014, a QOL assessment was done in survivors with the use of the Short Form Health Survey (SF-36) and the Severe Respiratory Insufficiency questionnaire.
Results: A total of 114 patients was included, of whom 59 were ventilator dependent and 55 were weaned at ICU discharge. One-year survival rates were 73 % and 69 %, respectively. Overall QOL scores for physical functioning were low, and not significantly different between patients ventilated and those weaned at ICU discharge; scores for social functioning and mental health were less below norm and similar between both groups.
Conclusions: Long-term survival in patients discharged from the ICU with tracheostomy and ventilator dependency after failure to wean was not significantly different from that of patients with tracheostomy and weaned at ICU discharge. Despite the physical QOL scores being low in both groups, mental QOL was acceptable. Given the intrinsic limitations of this retrospective study, prospective and preferentially multicenter studies are required to confirm these preliminary results
Patterns of infection and impact on outcome in haematology patients admitted to intensive care
Noninvasive mechanical ventilation in high-risk pulmonary infections: a clinical review
The aim of this article was to review the role of noninvasive ventilation (NIV) in acute pulmonary infectious diseases, such as severe acute respiratory syndrome (SARS), H1N1 and tuberculosis, and to assess the risk of disease transmission with the use of NIV from patients to healthcare workers. We performed a clinical review by searching Medline and EMBASE. These databases were searched for articles on "clinical trials" and "randomised controlled trials". The keywords selected were non-invasive ventilation pulmonary infections, influenza-A (H1N1), SARS and tuberculosis. These terms were cross-referenced with the following keywords: health care workers, airborne infections, complications, intensive care unit and pandemic. The members of the International NIV Network examined the major results regarding NIV applications and SARS, H1N1 and tuberculosis. Cross-referencing mechanical ventilation with SARS yielded 76 studies, of which 10 studies involved the use of NIV and five were ultimately selected for inclusion in this review. Cross-referencing with H1N1 yielded 275 studies, of which 27 involved NIV. Of these, 22 were selected for review. Cross-referencing with tuberculosis yielded 285 studies, of which 15 involved NIV and from these seven were selected. In total 34 studies were selected for this review. NIV, when applied early in selected patients with SARS, H1N1 and acute pulmonary tuberculosis infections, can reverse respiratory failure. There are only a few reports of infectious disease transmission among healthcare workers
Optimal sensitometric curves of Kodak EDR2 film for dynamic intensity modulated radiation therapy verification
Analysis of the surface state of epi-ready Ge wafers
The surface state of Ge epi-ready wafers (such as those used on III-V multijunction solar cells) supplied by two different vendors has been studied using X-ray photoemission spectroscopy. Our experimental results show that the oxide layer on the wafer surface is formed by GeO and GeO2. This oxide layer thickness differs among wafers coming from different suppliers. Besides, several contaminants appear on the wafer surfaces, carbon and probably chlorine being common to every wafer, irrespective of its origin. Wafers from one of the vendors show the presence of carbonates at their surfaces. On such wafers, traces of potassium seem to be present too
Implications of rising temperatures for gametophyte performance of two kelp species from Arctic waters
The aim of this study was to determine the temperature effects on photosynthesis, growth and reproduction in gametophytes of Alaria esculenta (Linnaeus) Greville and Saccharina latissima (Linnaeus) C. E. Lane, C. Mayes, Druehl et G. W. Saunders from the Artic waters. After 24 days of culture, no gametophytes of either species survived at 20 degrees C. Most growth parameters were greater at 10-15 degrees C than at 5 degrees C. Length and width were similar for both species, but area was greater for A. esculenta and cell number was greater for S. latissima. Female gametophytes were larger than male gametophytes in width and area, but the opposite was observed in cell number. In A. esculenta, but not for S. latissima, the percentage of female gametophytes decreased with increasing temperature. Alaria esculenta female gametophytes produced more sporophytes at 5 degrees C than at 10 degrees C, with no sporophytes at 15 degrees C. In S. latissima, all female gametophytes produced sporophytes at both 5 degrees C and 10 degrees C, with a small percentage of sporophytes at 15 degrees C. Saccharina latissima still had a measurable F v/F m at 20 degrees C, while the F v/F m of A. esculenta was zero at this temperature. Maximum relative electron transport rate (rETR(max)) and non-photochemical quenching (NPQ) were constant in the male and female gametophytes of A. esculenta and the male gametophytes of S. latissima at temperatures between 5 degrees C and 15 degrees C. Photosynthesis was saturated at a higher irradiance in A. esculenta than in S. latissima
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