The detection of low-energy deposition in the range of sub-eV through ionization using germanium (Ge) with a bandgap of
∼
0.7 eV requires internal amplification of the charge signal. This can be ...achieved through high electric field that accelerates charge carriers, which can then generate more charge carriers. The minimum electric field required to generate internal charge amplification is derived for different temperatures. We report the development of a planar point contact Ge detector in terms of its fabrication and the measurements of its leakage current and capacitance as a function of applied bias voltage. With the determination of the measured depletion voltage, the field distribution is calculated using GeFiCa, which predicts that the required electric field for internal charge amplification can be achieved in proximity to the point contact. The energy response to an Am-241 source is characterized and discussed. We conclude that such a detector with internal charge amplification can be used to search for low-mass dark matter.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Exacerbations are major contributors to morbidity and mortality in patients with chronic obstructive pulmonary disease (COPD), and respiratory bacterial and viral infections are an important trigger. ...However, using conventional diagnostic techniques, a causative agent is not always found. Metagenomic next-generation sequencing (mNGS) allows analysis of the complete virome, but has not yet been applied in COPD exacerbations.
To study the respiratory virome in nasopharyngeal samples during COPD exacerbations using mNGS.
88 nasopharyngeal swabs from 63 patients from the Bergen COPD Exacerbation Study (2006-2010) were analysed by mNGS and in-house qPCR for respiratory viruses. Both DNA and RNA were sequenced simultaneously using an Illumina library preparation protocol with in-house adaptations.
By mNGS, 24/88 samples tested positive. Sensitivity and specificity, as compared with PCR, were 96% and 98% for diagnostic targets (23/24 and 1093/1120, respectively). Additional viral pathogens detected by mNGS were herpes simplex virus type 1 and coronavirus OC43. A positive correlation was found between Cq value and mNGS viral normalized species reads (log value) (p = 0.002). Patients with viral pathogens had lower percentages of bacteriophages (p<0.001). No correlation was found between viral reads and clinical markers.
The mNGS protocol used was highly sensitive and specific for semi-quantitative detection of respiratory viruses. Excellent negative predictive value implicates the power of mNGS to exclude any pathogenic respiratory viral infectious cause in one test, with consequences for clinical decision making. Reduced abundance of bacteriophages in COPD patients with viral pathogens implicates skewing of the virome during infection, with potential consequences for the bacterial populations, during infection.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this Letter, we present a spectacular eruptive flare (X8.2) associated with a coronal mass ejection on 2017 September 10 at the west limb of the Sun. A flux rope eruption is followed by the ...inflow, the formation of a current sheet, and a cusp structure, which were simultaneously observed during the occurrence of this flare. The hierarchical layers of the cusp-shaped structure are well observed in 131 observation. The scenario that can be created from these observations is very consistent with the predictions of some eruptive models. Except for the characteristics mentioned above in the process of the flare predicted by classical eruption models, the current sheet separating into several small current sheets is also observed at the final stage of the flux rope eruption. The quantitative calculation of the velocities and accelerations of the inflow, hot cusp structure, and post-flare loops is presented. The width of the current sheet is estimated to be about 3 × 103 km. These observations are very useful in understanding the process of solar eruptions.
The Large Underground Xenon (LUX) experiment is a dual-phase xenon time-projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota). The LUX cryostat was filled for ...the first time in the underground laboratory in February 2013. We report results of the first WIMP search data set, taken during the period from April to August 2013, presenting the analysis of 85.3 live days of data with a fiducial volume of 118 kg. A profile-likelihood analysis technique shows our data to be consistent with the background-only hypothesis, allowing 90% confidence limits to be set on spin-independent WIMP-nucleon elastic scattering with a minimum upper limit on the cross section of 7.6 × 10(-46) cm(2) at a WIMP mass of 33 GeV/c(2). We find that the LUX data are in disagreement with low-mass WIMP signal interpretations of the results from several recent direct detection experiments.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Circulating tumor cells (CTCs) may have utility as surrogate biomarkers and "virtual" biopsies. We report the clinical significance and molecular characteristics of CTCs and CTC clusters, termed ...circulating tumor microemboli (CTM), detected in patients with small-cell lung cancer (SCLC) undergoing standard treatment.
Serial blood samples from 97 patients receiving chemotherapy were analyzed using EpCam-based immunomagnetic detection and a filtration-based technique. Proliferation status (Ki67) and apoptotic morphology were examined. Associations of CTC and CTM number with clinical factors and prognosis were determined.
CTCs were present in 85% of patients (77 of 97 patients) and were abundant (mean ± standard deviation = 1,589 ± 5,565). CTM and apoptotic CTCs were correlated with total CTC number and were detected in 32% and 57% of patients, respectively. Pretreatment CTCs, change in CTC number after one cycle of chemotherapy, CTM, and apoptotic CTCs were independent prognostic factors. Overall survival was 5.4 months for patients with ≥ 50 CTCs/7.5 mL of blood and 11.5 months (P < .0001) for patients with less than 50 CTCs/7.5 mL of blood before chemotherapy (hazard ratio = 2.45; 95% CI, 1.39 to 4.30; P = .002). Subpopulations of apoptotic and of proliferating solitary CTCs were detected, whereas neither were observed within cell clusters (CTM), implicating both protection from anoikis and relative resistance to cytotoxic drugs for cells within CTM.
Both baseline CTC number and change in CTC number after one cycle of chemotherapy are independent prognostic factors for SCLC. Molecular comparison of CTCs to cells in CTM may provide novel insights into SCLC biology.
For the first time, time-dependent internal charge amplification through impact ionization has been observed in a planar germanium (Ge) detector operated at cryogenic temperature. In a time period of ...30 and 45 min after applying a bias voltage, the charge energy corresponding to a baseline of the 59.54 keV
γ
rays from a
241
Am source is amplified for a short period of time and then decreases back to the baseline. The amplification of charge energy depends strongly on the applied positive bias voltage with drifting holes across the detector. No such phenomenon is visible with drifting electrons across the detector. We find that the observed charge amplification is dictated by the impact ionization of charged states, which has a strong correlation with impurity level and applied electric field. We analyze the dominant physics mechanisms that are responsible for the creation and the impact ionization of charged states. Our analysis suggests that the appropriate level of impurity in a Ge detector can enhance charge yield through the impact ionization of charged states to achieve extremely low-energy detection threshold (< 10 meV) for MeV-scale dark matter searches if the charge amplification can be stabilized.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background. The study aimed to evaluate the risk of hepatitis C virus (HCV) infection on hepatic and extrahepatic deaths. Methods. A cohort of 23 820 adults aged 30—65 years old were enrolled during ...1991—1992. The seromarkers hepatitis B surface antigen (HBsAg), anti-HCV, and serum HCV RNA levels at study entry were tested. The vital status was ascertained through computerized linkage with national death certification profiles from 1991 to 2008. Results. There were 19 636 HBsAg-seronegatives, including 18 541 anti-HCV seronegatives and 1095 anti-HCV seropositives. Among anti-HCV seropositives, 69.4% had detectable serum HCV RNA levels. There were 2394 deaths that occurred during an average follow-up period of 16.2 years. Compared with anti-HCV seronegatives, anti-HCV seropositives had higher mortality from both hepatic and extrahepatic diseases, showing multivariate-adjusted hazard ratio (95% confidence interval) of 1.89 (1.66—2.15) for all causes of death; 12.48 (9.34—16.66) for hepatic diseases; 1.35 (1.15—1.57) for extrahepatic diseases; 1.50 (1.10—2.03) for circulatory diseases; 2.77 (1.49—5.15) for nephritis, nephrotic syndrome, and nephrosis; 4.08 (1.38—12.08) for esophageal cancer; 4.19 (1.18—14.94) for prostate cancer; and 8.22 (1.36—49.66) for thyroid cancer. Anti-HCV seropositives with detectable HCV RNA levels had significantly higher mortality from hepatic and extrahepatic diseases than anti-HCV seropositives with undetectable HCV RNA. Conclusions. Monitoring HCV RNA in anti-HCV seropositives is essential for the prediction of mortality associated with hepatitis C.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
We address the problem of ambulance dispatching, in which we must decide which ambulance to send to an incident in real time. In practice, it is commonly believed that the ‘closest idle ambulance’ ...rule is near-optimal and it is used throughout most literature. In this paper, we present alternatives to the classical closest idle ambulance rule. Most ambulance providers as well as researchers focus on minimizing the fraction of arrivals later than a certain threshold time, and we show that significant improvements can be obtained by our alternative policies. The first alternative is based on a Markov decision problem (MDP), that models more than just the number of idle vehicles, while remaining computationally tractable for reasonably-sized ambulance fleets. Second, we propose a heuristic for ambulance dispatching that can handle regions with large numbers of ambulances. Our main focus is on minimizing the fraction of arrivals later than a certain threshold time, but we show that with a small adaptation our MDP can also be used to minimize the average response time. We evaluate our policies by simulating a large emergency medical services region in the Netherlands. For this region, we show that our heuristic reduces the fraction of late arrivals by 18 % compared to the ‘closest idle’ benchmark policy. A drawback is that this heuristic increases the average response time (for this problem instance with 37 %). Therefore, we do not claim that our heuristic is practically preferable over the closest-idle method. However, our result sheds new light on the popular belief that the closest idle dispatch policy is near-optimal when minimizing the fraction of late arrivals.
Cancer registration provides core information for cancer surveillance and control. The population-based Taiwan Cancer Registry was implemented in 1979. After the Cancer Control Act was promulgated in ...2003, the completeness (97%) and data quality of cancer registry database has achieved at an excellent level. Hospitals with 50 or more beds, which provide outpatient and hospitalized cancer care, are recruited to report 20 items of information on all newly diagnosed cancers to the central registry office (called short-form database). The Taiwan Cancer Registry is organized and funded by the Ministry of Health and Welfare. The National Taiwan University has been contracted to operate the registry and organized an advisory board to standardize definitions of terminology, coding and procedures of the registry's reporting system since 1996. To monitor the cancer care patterns and evaluate the cancer treatment outcomes, central cancer registry has been reformed since 2002 to include detail items of the stage at diagnosis and the first course of treatment (called long-form database). There are 80 hospitals, which count for >90% of total cancer cases, involved in the long-form registration. The Taiwan Cancer Registry has run smoothly for >30 years, which provides essential foundation for academic research and cancer control policy in Taiwan.
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