122 research outputs found

    Influence of Annealing on the Optical and Scintillation Properties of CaWO4_4 Single Crystals

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    We investigate the influence of oxygen annealing on the room temperature optical and scintillation properties of CaWO4_4 single crystals that are being produced for direct Dark Matter search experiments. The applied annealing procedure reduces the absorption coefficient at the peak position of the scintillation spectrum (430\sim430 nm) by a factor of 6\sim6 and leads to an even larger reduction of the scattering coefficient. Furthermore, the annealing has no significant influence on the \emph{intrinsic} light yield. An additional absorption occurring at 400\sim400 nm suggests the formation of O^- hole centers. Light-yield measurements at room temperature where one crystal surface was mechanically roughened showed an increase of the \emph{measured} light yield by 40\sim40 % and an improvement of the energy resolution at 59.5 keV by 12\sim12 % for the annealed crystal. We ascribe this result to the reduction of the absorption coefficient while the surface roughening is needed to compensate for the also observed reduction of the scattering coefficient after annealing

    A distinct CD38+CD45RA+ population of CD4+, CD8+, and double-negative T cells is controlled by FAS.

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    The identification and characterization of rare immune cell populations in humans can be facilitated by their growth advantage in the context of specific genetic diseases. Here, we use autoimmune lymphoproliferative syndrome to identify a population of FAS-controlled TCRαβ+ T cells. They include CD4+, CD8+, and double-negative T cells and can be defined by a CD38+CD45RA+T-BET- expression pattern. These unconventional T cells are present in healthy individuals, are generated before birth, are enriched in lymphoid tissue, and do not expand during acute viral infection. They are characterized by a unique molecular signature that is unambiguously different from other known T cell differentiation subsets and independent of CD4 or CD8 expression. Functionally, FAS-controlled T cells represent highly proliferative, noncytotoxic T cells with an IL-10 cytokine bias. Mechanistically, regulation of this physiological population is mediated by FAS and CTLA4 signaling, and its survival is enhanced by mTOR and STAT3 signals. Genetic alterations in these pathways result in expansion of FAS-controlled T cells, which can cause significant lymphoproliferative disease

    Surface functionalisation of nanodiamonds for human neural stem cell adhesion and proliferation.

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    Biological systems interact with nanostructured materials on a sub-cellular level. These interactions may govern cell behaviour and the precise control of a nanomaterial's structure and surface chemistry allow for a high degree of tunability to be achieved. Cells are surrounded by an extra-cellular matrix with nano-topographical properties. Diamond based materials, and specifically nanostructured diamond has attracted much attention due to its extreme electrical and mechanical properties, chemical inertness and biocompatibility. Here the interaction of nanodiamond monolayers with human Neural Stem Cells (hNSCs) has been investigated. The effect of altering surface functionalisation of nanodiamonds on hNSC adhesion and proliferation has shown that confluent cellular attachment occurs on oxygen terminated nanodiamonds (O-NDs), but not on hydrogen terminated nanodiamonds (H-NDs). Analysis of H and O-NDs by Atomic Force Microscopy, contact angle measurements and protein adsorption suggests that differences in topography, wettability, surface charge and protein adsorption of these surfaces may underlie the difference in cellular adhesion of hNSCs reported here

    Cold and Ultracold Molecules: Science, Technology, and Applications

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    This article presents a review of the current state of the art in the research field of cold and ultracold molecules. It serves as an introduction to the Special Issue of the New Journal of Physics on Cold and Ultracold Molecules and describes new prospects for fundamental research and technological development. Cold and ultracold molecules may revolutionize physical chemistry and few body physics, provide techniques for probing new states of quantum matter, allow for precision measurements of both fundamental and applied interest, and enable quantum simulations of condensed-matter phenomena. Ultracold molecules offer promising applications such as new platforms for quantum computing, precise control of molecular dynamics, nanolithography, and Bose-enhanced chemistry. The discussion is based on recent experimental and theoretical work and concludes with a summary of anticipated future directions and open questions in this rapidly expanding research field.Comment: 82 pages, 9 figures, review article to appear in New Journal of Physics Special Issue on Cold and Ultracold Molecule

    Microbiological testing of adults hospitalised with community-acquired pneumonia: An international study

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    This study aimed to describe real-life microbiological testing of adults hospitalised with community-acquired pneumonia (CAP) and to assess concordance with the 2007 Infectious Diseases Society of America (IDSA)/American Thoracic Society (ATS) and 2011 European Respiratory Society (ERS) CAP guidelines. This was a cohort study based on the Global Initiative for Methicillin-resistant Staphylococcus aureus Pneumonia (GLIMP) database, which contains point-prevalence data on adults hospitalised with CAP across 54 countries during 2015. In total, 3702 patients were included. Testing was performed in 3217 patients, and included blood culture (71.1%), sputum culture (61.8%), Legionella urinary antigen test (30.1%), pneumococcal urinary antigen test (30.0%), viral testing (14.9%), acute-phase serology (8.8%), bronchoalveolar lavage culture (8.4%) and pleural fluid culture (3.2%). A pathogen was detected in 1173 (36.5%) patients. Testing attitudes varied significantly according to geography and disease severity. Testing was concordant with IDSA/ATS and ERS guidelines in 16.7% and 23.9% of patients, respectively. IDSA/ATS concordance was higher in Europe than in North America (21.5% versus 9.8%; p<0.01), while ERS concordance was higher in North America than in Europe (33.5% versus 19.5%; p<0.01). Testing practices of adults hospitalised with CAP varied significantly by geography and disease severity. There was a wide discordance between real-life testing practices and IDSA/ATS/ERS guideline recommendations

    Prevalence and etiology of community-acquired pneumonia in immunocompromised patients

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    Background. The correct management of immunocompromised patients with pneumonia is debated. We evaluated the prevalence, risk factors, and characteristics of immunocompromised patients coming from the community with pneumonia. Methods. We conducted a secondary analysis of an international, multicenter study enrolling adult patients coming from the community with pneumonia and hospitalized in 222 hospitals in 54 countries worldwide. Risk factors for immunocompromise included AIDS, aplastic anemia, asplenia, hematological cancer, chemotherapy, neutropenia, biological drug use, lung transplantation, chronic steroid use, and solid tumor. Results. At least 1 risk factor for immunocompromise was recorded in 18% of the 3702 patients enrolled. The prevalences of risk factors significantly differed across continents and countries, with chronic steroid use (45%), hematological cancer (25%), and chemotherapy (22%) the most common. Among immunocompromised patients, community-acquired pneumonia (CAP) pathogens were the most frequently identified, and prevalences did not differ from those in immunocompetent patients. Risk factors for immunocompromise were independently associated with neither Pseudomonas aeruginosa nor non\u2013community-acquired bacteria. Specific risk factors were independently associated with fungal infections (odds ratio for AIDS and hematological cancer, 15.10 and 4.65, respectively; both P = .001), mycobacterial infections (AIDS; P = .006), and viral infections other than influenza (hematological cancer, 5.49; P < .001). Conclusions. Our findings could be considered by clinicians in prescribing empiric antibiotic therapy for CAP in immunocompromised patients. Patients with AIDS and hematological cancer admitted with CAP may have higher prevalences of fungi, mycobacteria, and noninfluenza viruses

    Burden and risk factors for Pseudomonas aeruginosa community-acquired pneumonia:a Multinational Point Prevalence Study of Hospitalised Patients

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    Pseudornonas aeruginosa is a challenging bacterium to treat due to its intrinsic resistance to the antibiotics used most frequently in patients with community-acquired pneumonia (CAP). Data about the global burden and risk factors associated with P. aeruginosa-CAP are limited. We assessed the multinational burden and specific risk factors associated with P. aeruginosa-CAP. We enrolled 3193 patients in 54 countries with confirmed diagnosis of CAP who underwent microbiological testing at admission. Prevalence was calculated according to the identification of P. aeruginosa. Logistic regression analysis was used to identify risk factors for antibiotic-susceptible and antibiotic-resistant P. aeruginosa-CAP. The prevalence of P. aeruginosa and antibiotic-resistant P. aeruginosa-CAP was 4.2% and 2.0%, respectively. The rate of P. aeruginosa CAP in patients with prior infection/colonisation due to P. aeruginosa and at least one of the three independently associated chronic lung diseases (i.e. tracheostomy, bronchiectasis and/or very severe chronic obstructive pulmonary disease) was 67%. In contrast, the rate of P. aeruginosa-CAP was 2% in patients without prior P. aeruginosa infection/colonisation and none of the selected chronic lung diseases. The multinational prevalence of P. aeruginosa-CAP is low. The risk factors identified in this study may guide healthcare professionals in deciding empirical antibiotic coverage for CAP patients

    Non-invasive central venous pressure measurement by compression ultrasound-A step into real life

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    Information on central venous pressure (CVP) is helpful in clinical situations like cardiac failure and sepsis. Compression ultrasound (CU) of a forearm vein has been shown to be a reliable method for CVP measurement when assessed by experienced personal under study conditions. To test the hypothesis, that CU can be reliably used for CVP measurement after a training program and using a portable ultrasound system, we investigated feasibility and accuracy of CU, comparing the results of vascular experts vs. trainees as well as high-end vs. a portable ultrasound system. METHODS: CU with non-invasive CVP measurement (CVP(ni)) was performed by four investigators in 50 patients of an intensive care unit and compared with invasive CVP measurement (CVP(i)). RESULTS: Feasibility was between 88 and 92% in the different investigator groups. CVP(ni) measurement showed a significant linear correlation (r=0.58-0.68; p<0.001) with CVP(i) in all groups. Mean difference between CVP(i) and CVP(ni) was 2.4+/-3.1mmHg and similar between the investigators. No differences were observed between measurements done by vascular experts and trainees, as well as between high-end and portable ultrasound systems. Further we demonstrated, that CU is able to detect changes in CVP during the respiratory cycle. CONCLUSIONS: After a training program CU can be used by non-vascular clinician for reliable CVP measurement with good quality portable systems. Furthermore, respiratory changes in CVP are detectable by CU. These data suggest CU to be an efficient method for measuring CVP under real life conditions

    Single cell analysis of mutations in the APC gene.

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    Mutation analysis of inherited monogenic diseases is an important aspect of preimplantation genetic diagnosis. Familial adenomatous polyposis of the colon is an autosomal dominant inherited disorder caused by mutations in the tumor suppressor gene adenomatous polyposis coli (APC). A characteristic of this severe disease is the development of thousands of polyps in the colon which untreated evolve into malignant colon carcinomas. Here we present a novel approach for the establishment of mutation detection in the APC gene in single cells applicable for preimplantation genetic diagnosis. Methods: Single fixed lymphocytes were isolated via laser microdissection and transferred to reaction centers of planar chemically structured glass slides via a recently developed horizontal low-pressure single particle adsorbing transfer system (SPATS). A multiplex nested polymerase chain reaction protocol in a 1-mu l reaction volume, followed by sequencing and fragment length analysis was applied in order to detect mutations in the APC gene. Results: Reliable isolation and transfer of single lymphocytes was demonstrated. High amplification efficiency and low allelic drop out (ADO) rates for polymorphic microsatellite markers and mutation specific amplification products of various mutations in the APC gene were obtained from fixed single cells. Conclusions: This novel nanotechnological downscaling approach enables a reliable validation of genetic testing using diploid single lymphocytes, and will open a wide range of single cell diagnostics
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