1,172 research outputs found
Digital multichannel photometer
System was developed for use in astronomy and other research areas concerned with detection of faint-light images. Photometer system is comparable in performance to good photomultiplier tube array except that digital electronics are used instead of analog
Radiation environment along the INTEGRAL orbit measured with the IREM monitor
The INTEGRAL Radiation Environment Monitor (IREM) is a payload supporting
instrument on board the INTEGRAL satellite. The monitor continually measures
electron and proton fluxes along the orbit and provides this information to the
spacecraft on board data handler. The mission alert system broadcasts it to the
payload instruments enabling them to react accordingly to the current radiation
level. Additionally, the IREM conducts its autonomous research mapping the
Earth radiation environment for the space weather program. Its scientific data
are available for further analysis almost without delay.Comment: 5 pages, 7 figures, accepted for publication in A+A letter
Are infestations of Cymomelanodactylus killing Acropora cytherea in the Chagos archipelago?
Associations between branching corals and infaunal crabs are well
known, mostly due to the beneficial effects of Trapezia and Tetralia
crabs in protecting host corals from crown-of-thorns starfish (e.g.,
Pratchett et al. 2000) and/or sedimentation (Stewart et al. 2006).
These crabs are obligate associates of live corals and highly prevalent
across suitable coral hosts, with 1–2 individuals per colony
(Patton 1994). Cymo melanodactylus (Fig. 1) are also prevalent in
branching corals, mostly Acropora, and are known to feed on live
coral tissue, but are generally found in low abundance (<3 per
colony) and do not significantly affect their host corals (e.g., Patton
1994). In the Chagos archipelago, however, infestations of Cymo
melanodactylus were found on recently dead and dying colonies of
Acropora cytherea
Modelling air and water two-phase annular flow in small horizontal pipe
Numerical study using Computational Fluid Dynamics (CFD) has been carried out to investigate flow behaviours and underlying physical phenomena associated with air/water two-phase flow inside a small horizontal tube of an inner diameter 8.8mm. The base liquid film thickness distributions, determined by either wavy or full annular flow regime, are compared with available experimental data. CFD simulation has successfully predicted the wavy structure applying a user defined function, which has coupled in ANSYS-FLUENT solver to correlate with other two-phase flow models under the Eulerian–Eulerian framework. Results from liquid distributions and two-phase flow behaviours have indicated the presence of strong gas/liquid interferences. This can largely contribute towards the thickening of the liquid film coverage along the top pipe wall surface for a fully developed annular flow, compared to those occurred in the wavy annular flow regime. This is due to possible earlier droplets broken down thus the liquid wavy front can travel from the low part of the pipe to the upper wall surface. Some discrepancies between CFD prediction and experimental data could be due to the limitation of CFD model as only a simplified 2D variant is adopted, rather than a full 3D transient two-phase flow model
Weld geometry strength effect in 2219-T87 aluminum
A theory of the effect of geometry on the mechanical properties of a butt weld joint is worked out based upon the soft interlayer weld model. Tensile tests of 45 TIG butt welds and 6 EB beads-on-plate in 1/4-in. 2219-T87 aluminum plate made under a wide range of heat sink and power input conditions are analyzed using this theory. The analysis indicates that purely geometrical effects dominate in determining variations in weld joint strength with heat sink and power input. Variations in weld dimensions with cooling rate are significant as well as with power input. Weld size is suggested as a better indicator of the condition of a weld joint than energy input
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Neurological, Cognitive, and Psychological Findings Among Survivors of Ebola Virus Disease From the 1995 Ebola Outbreak in Kikwit, Democratic Republic of Congo: A Cross-sectional Study.
BackgroundClinical sequelae of Ebola virus disease (EVD) have not been described more than 3 years postoutbreak. We examined survivors and close contacts from the 1995 Ebola outbreak in Kikwit, Democratic Republic of Congo (DRC), and determined prevalence of abnormal neurological, cognitive, and psychological findings and their association with EVD survivorship.MethodsFrom August to September 2017, we conducted a cross-sectional study in Kikwit, DRC. Over 2 decades after the EVD outbreak, we recruited EVD survivors and close contacts from the outbreak to undergo physical examination and culturally adapted versions of the Folstein mini-mental status exam (MMSE) and Goldberg anxiety and depression scale (GADS). We estimated the strength of relationships between EVD survivorship and health outcomes using linear regression models by comparing survivors versus close contacts, adjusting for age, sex, educational level, marital status, and healthcare worker status.ResultsWe enrolled 20 EVD survivors and 187 close contacts. Among the 20 EVD survivors, 4 (20%) reported at least 1 abnormal neurological symptom, and 3 (15%) had an abnormal neurological examination. Among the 187 close contacts, 14 (11%) reported at least 1 abnormal neurologic symptom, and 9 (5%) had an abnormal neurological examination. EVD survivors had lower mean MMSE and higher mean GADS scores as compared to close contacts (MMSE: adjusted coefficient: -1.85; 95% confidence interval [CI]: -3.63, -0.07; GADS: adjusted coefficient: 3.91; 95% CI: 1.76, 6.04).ConclusionsEVD survivors can have lower cognitive scores and more symptoms of depression and anxiety than close contacts more than 2 decades after Ebola virus outbreaks
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Design and testing of a unique active Compton-suppressed LaBr3(Ce) detector system for improved sensitivity assays of TRU in remote-handled TRU wastes
The US Department of Energy’s transuranic (TRU) waste inventory includes about 4,500 m3 of remote-handled TRU (RH-TRU) wastes composed of a variety of containerized waste forms having a contact surface dose rate that exceeds 2 mSv/hr (200 mrem/hr) containing waste materials with a total TRU concentration greater than 3700 Bq/g (100 nCi/g). As part of a research project to investigate the use of active Compton-suppressed room-temperature gamma-ray detectors for direct non-destructive quantification of the TRU content of these RH-TRU wastes, we have designed and purchased a unique detector system using a LaBr3(Ce) primary detector and a NaI(Tl) suppression mantle. The LaBr3(Ce) primary detector is a cylindrical unit ~25 mm in diameter by 76 mm long viewed by a 38 mm diameter photomultiplier. The NaI(Tl) suppression mantle (secondary detector) is 175 mm by 175 mm with a center well that accommodates the primary detector. An important feature of this arrangement is the lack of any “can” between the primary and secondary detectors. These primary and secondary detectors are optically isolated by a thin layer (.003") of aluminized kapton, but the hermetic seal and thus the aluminum can surrounds the outer boundary of the detector system envelope. The hermetic seal at the primary detector PMT is at the PMT wall. This arrangement virtually eliminates the “dead” material between the primary and secondary detectors, a feature that preliminary modeling indicated would substantially improve the Compton suppression capability of this device. This paper presents both the expected performance of this unit determined from modeling with MCNPX, and the performance measured in our laboratory with radioactive sources
Electronic structure of LaBr3 from quasi-particle self-consistent GW calculations
Rare-earth based scintillators in general and lanthanum bromide (LaBr_3) in
particular represent a challenging class of materials due to pronounced
spin-orbit coupling and subtle interactions between d and f states that cannot
be reproduced by standard density functional theory (DFT). Here a detailed
investigation of the electronic band structure of LaBr_3 using the
quasi-particle self-consistent GW (QPscGW) method is presented. This
parameter-free approach is shown to yield an excellent description of the
electronic structure of LaBr_3. Specifically it is able to reproduce the band
gap, the correct level ordering and spacing of the 4f and 5d states, as well as
the spin-orbit splitting of La-derived states. The QPscGW results are
subsequently used to benchmark several computationally less demanding
techniques including DFT+U, hybrid exchange-correlation functionals, and the
G_0W_0 method. Spin-orbit coupling is included self-consistently at each QPscGW
iteration and maximally localized Wannier functions are used to interpolate
quasi-particle energies. The QPscGW results provide an excellent starting point
for investigating the electronic structure of excited states, charge
self-trapping, and activator ions in LaBr_3 and related materials.Comment: 8 pages, 7 figure
Rhomboid family member 2 regulates cytoskeletal stress-associated Keratin 16.
Keratin 16 (K16) is a cytoskeletal scaffolding protein highly expressed at pressure-bearing sites of the mammalian footpad. It can be induced in hyperproliferative states such as wound healing, inflammation and cancer. Here we show that the inactive rhomboid protease RHBDF2 (iRHOM2) regulates thickening of the footpad epidermis through its interaction with K16. K16 expression is absent in the thinned footpads of irhom2-/- mice compared with irhom2+/+mice, due to reduced keratinocyte proliferation. Gain-of-function mutations in iRHOM2 underlie Tylosis with oesophageal cancer (TOC), characterized by palmoplantar thickening, upregulate K16 with robust downregulation of its type II keratin binding partner, K6. By orchestrating the remodelling and turnover of K16, and uncoupling it from K6, iRHOM2 regulates the epithelial response to physical stress. These findings contribute to our understanding of the molecular mechanisms underlying hyperproliferation of the palmoplantar epidermis in both physiological and disease states, and how this 'stress' keratin is regulated
Anti-tumor activity and mechanistic characterization of APE1/Ref-1 inhibitors in bladder cancer
Bladder cancer is the ninth most common cause of cancer-related deaths worldwide. Although cisplatin is used routinely in treating bladder cancer, refractory disease remains lethal for many patients. The recent addition of immunotherapy has improved patient outcomes; however, a large cohort of patients does not respond to these treatments. Therefore, identification of innovative molecular targets for bladder cancer is crucial. Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1) is a multifunctional protein involved in both DNA repair and activation of transcription factors through reduction-oxidation (redox) regulation. High APE1/Ref-1 expression is associated with shorter patient survival time in many cancer types. In this study, we found high APE1/Ref-1 expression in human bladder cancer tissue relative to benign urothelium. Inhibition of APE1/Ref-1 redox signaling using APE1/Ref-1-specific inhibitors attenuates bladder cancer cell proliferation in monolayer, in three-dimensional cultures, and in vivo. This inhibition corresponds with an increase in apoptosis and decreased transcriptional activity of NF-ÎşB and STAT3, transcription factors known to be regulated by APE1/Ref-1, resulting in decreased expression of downstream effectors survivin and Cyclin D1 in vitro and in vivo. We also demonstrate that in vitro treatment of bladder cancer cells with APE1/Ref-1 redox inhibitors in combination with standard-of-care chemotherapy cisplatin is more effective than cisplatin alone at inhibiting cell proliferation. Collectively, our data demonstrate that APE1/Ref-1 is a viable drug target for the treatment of bladder cancer, provide a mechanism of APE1/Ref-1 action in bladder cancer cells, and support the use of novel redox-selective APE1/Ref-1 inhibitors in clinical studies. SIGNIFICANCE: This work identifies a critical mechanism for APE1/Ref-1 in bladder cancer growth and provides compelling preclinical data using selective redox activity inhibitors of APE1/Ref-1 in vitro and in vivo
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