Metal-insulator crossover in monolayer MoS2.

We report on transport measurements in monolayer MoS2devices, close to the bottom of the conduction band edge. These devices were annealedin situbefore electrical measurements. This allows us to obtain good ohmic contacts at low temperatures, and to measure precisely the conductivity and mobility via four-probe measurements. The measured effective mobility up toµeff= 180 cm2V-1s-1is among the largest obtained in CVD-grown MoS2monolayer devices. These measurements show that electronic transport is of the insulating type forσ≤ 1.4e2/handn≤ 1.7 × 1012cm-2, and a crossover to a metallic regime is observed above those values. In the insulating regime, thermally activated transport dominates at high temperature (T> 120 K). At lower temperatures, conductivity is driven by Efros-Schklovkii variable range hopping in all measured devices, with a universal and constant hopping prefactor, that is a clear indication that hopping is not phonon-mediated. At higher carrier density, and high temperature, the conductivity is well modeled by the Boltzmann equation for a non-interacting Fermi gas, taking into account both phonon and impurity scatterings. Finally, even if this apparent metal-insulator transition can be explained by phonon-related phenomena at high temperature, the possibility of a genuine 2D MIT cannot be ruled out, as we can observe a clear power-law diverging localization length close to the transition, and a one-parameter scaling can be realized.

Measurement of polarization observables T, P, and H in π0 and η photoproduction off quasi-free nucleons.

The target asymmetry T, recoil asymmetry P, and beam-target double polarization observable H were determined in exclusive π0 and η photoproduction off quasi-free protons and, for the first time, off quasi-free neutrons. The experiment was performed at the electron stretcher accelerator ELSA in Bonn, Germany, with the Crystal Barrel/TAPS detector setup, using a linearly polarized photon beam and a transversely polarized deuterated butanol target. Effects from the Fermi motion of the nucleons within deuterium were removed by a full kinematic reconstruction of the final state invariant mass. A comparison of the data obtained on the proton and on the neutron provides new insight into the isospin structure of the electromagnetic excitation of the nucleon. Earlier measurements of polarization observables in the γp→π0p and γp→ηp reactions are confirmed. The data obtained on the neutron are of particular relevance for clarifying the origin of the narrow structure in the ηn system at W=1.68GeV. A comparison with recent partial wave analyses favors the interpretation of this structure as arising from interference of the S11(1535) and S11(1650) resonances within the S11-partial wave.

Development and validation of the German translation of the views on inpatient care (VOICE-DE) outcome measure to assess service users' perceptions of inpatient psychiatric care.

BACKGROUND: Service user satisfaction in inpatient psychiatric care is often measured with instruments that have been designed by professionals, without involving the perspective of service users. Views on Inpatient Care (VOICE), developed in England, is among the first service-user-generated outcome measures which included service users' perspectives in the process. AIMS: In this study, we aimed to validate a German version of VOICE. METHODS: The original questionnaire was translated into German and validated using data collected from 163 inpatients undergoing treatment in a psychiatric hospital. The instrument was tested for its psychometric properties, focusing on measurements of reliability and construct validity. Also, we assessed the impact of demographic variables. Finally, factorial analyses were carried out to compare the underlying factorial structure to the English version. RESULTS: The analyses revealed a high internal consistency (α = 0.90). No significant impact of demographic variables was observed. Factorial analyses indicated a one-factor structure which accounted for 40.39% of variance. CONCLUSIONS: Psychometrical evaluation of VOICE-DE indicated the questionnaire to be a suitable tool to assess service users' personal experience with treatment and satisfaction in German.

HIV DNA reservoir and elevated PD-1 expression of CD4 T-cell subsets particularly persist in the terminal ileum of HIV-positive patients despite cART.

OBJECTIVES: Despite its importance as an HIV anatomic sanctuary, little is known about the characteristics of the HIV reservoir in the terminal ileum (TI). In blood, the immune checkpoint inhibitor programmed-death-1 (PD-1) has been linked to the HIV reservoir and T-cell immune dysfunction. We thus evaluated PD-1 expression and cell-associated HIV DNA in memory CD4 T-cell subsets from TI, peripheral blood (PB) and rectum (RE) of untreated and treated HIV-positive patients to identify associations between PD-1 and HIV reservoir in other sites. METHODS: Using mononuclear cells from PB, TI and RE of untreated HIV-positive (N = 6), treated (n = 18) HIV-positive and uninfected individuals (n = 16), we identified and sorted distinct memory CD4 T-cell subsets by flow cytometry, quantified their cell-associated HIV DNA using quantitative PCR and assessed PD-1 expression levels using geometric mean fluorescence intensity. Combined HIV-1 RNA in situ hybridization and immunohistochemistry was performed on ileal biopsy sections. RESULTS: Combined antiretroviral therapy (cART)-treated patients with undetectable HIV RNA and significantly lower levels of HIV DNA in PB showed particularly high PD-1 expression in PB and TI, and high HIV DNA levels in TI, irrespective of clinical characteristics. By contrast, in treatment-naïve patients HIV DNA levels in memory CD4 T-cell subsets were high in PB and TI. CONCLUSION: Elevated PD-1 expression on memory CD4 T-cells in PB and TI despite treatment points to continuous immune dysfunction and underlines the importance of evaluating immunotherapy in reversing HIV latency and T-cell reconstitution. As HIV DNA particularly persists in TI despite cART, investigating samples from TI is crucial in understanding HIV immunopathogenesis.

Measurement of the helicity asymmetry E for the reaction γ p → π 0 p : The CBELSA/TAPS Collaboration.

A measurement of the double-polarization observable E for the reaction γ p → π 0 p is reported. The data were taken with the CBELSA/TAPS experiment at the ELSA facility in Bonn using the Bonn frozen-spin butanol (C 4 H 9 OH) target, which provided longitudinally-polarized protons. Circularly-polarized photons were produced via bremsstrahlung of longitudinally-polarized electrons. The data cover the photon energy range from E γ = 600 to 2310 MeV and nearly the complete angular range. The results are compared to and have been included in recent partial wave analyses.

Observation of the pη

Data on the beam asymmetry Σ in the photoproduction of η mesons off protons are reported for tagged photon energies from 1130 to 1790 MeV (mass range from W=1748 MeV to W=2045 MeV). The data cover the full solid angle that allows for a precise moment analysis. For the first time, a strong cusp effect in a polarization observable has been observed that is an effect of a branch-point singularity at the pη^{'} threshold [E_{γ}=1447 MeV (W=1896 MeV)]. The latest BnGa partial wave analysis includes the new beam asymmetry data and yields a strong indication for the N(1895)1/2^{-} nucleon resonance, demonstrating the importance of including all singularities for a correct determination of partial waves and resonance parameters.

[Primary cutaneous lymphoma-a case series of 163 patients]. / Primär kutane Lymphome ­ eine Fallserie von 163 Patienten.

BACKGROUND: In addition to a broad and clinically diverse spectrum of known primary cutaneous lymphomas, for which an incidence of 1-3:100,000 is postulated, each year further entities are specified and defined. The goal is the presentation of a case series from daily clinical routine. METHODS: Over a period of 6 years and 2 months, patients consulting the Department of Dermatology, Medical Center University of Freiburg, were registered. Subsequently, collectives of mycosis fungoides (MF), Sezary syndrome (SS), CD30+ lymphoproliferative diseases, single cases with rare primary cutaneous lymphomas, and subcollectives of B­cell lymphomas were examined. The high number of MF cases allowed the additional quantitative analyses of the types of therapies used in this group. RESULTS: Yearly 16-25 new diagnoses of primary cutaneous lymphoma are made. The evaluation of 163 primary cutaneous lymphoma revealed 111 cases with MF (68.1%), including 9 particular variants, 15 primary cutaneous CD30+ lymphoproliferative diseases (9.2%) dominated by 10 lymphomatoid papulosis (LyP), in addition to 5 primary cutaneous anaplastic large cell lymphoma (PCALCL), 6 SS (3.68%), and 24 cutaneous B­cell lymphomas (14-72%). Three cases with rare primary cutaneous T/NK cell lymphomas are addressed in detail. In all, 82% of MF cases were stage IA and IB. The descending use of therapies for stage I-III included steroids and diverse UV therapies followed by bexarotene, interferon-α, methotrexate, and extracorporal photophoresis. CONCLUSIONS: Diagnoses of cutaneous lymphomas belong to a vast spectrum of differential diagnoses. This registry describes frequent findings and shows rare variants. You can only diagnose what you know; accordingly, a collection of case reports, which we wish to encourage, can help in processing and specification of entities.

Beam-Target Helicity Asymmetry for γ[over →]n[over →]→π

We report the first beam-target double-polarization asymmetries in the γ+n(p)→π^{-}+p(p) reaction spanning the nucleon resonance region from invariant mass W=1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses and have led to significant revisions for several γnN^{*} resonance photocouplings.

Pancreatogastrostomy Versus Pancreatojejunostomy for RECOnstruction After PANCreatoduodenectomy (RECOPANC, DRKS 00000767): Perioperative and Long-term Results of a Multicenter Randomized Controlled Trial.

OBJECTIVES: To assess pancreatic fistula rate and secondary endpoints after pancreatogastrostomy (PG) versus pancreatojejunostomy (PJ) for reconstruction in pancreatoduodenectomy in the setting of a multicenter randomized controlled trial. BACKGROUND: PJ and PG are established methods for reconstruction in pancreatoduodenectomy. Recent prospective trials suggest superiority of the PG regarding perioperative complications. METHODS: A multicenter prospective randomized controlled trial comparing PG with PJ was conducted involving 14 German high-volume academic centers for pancreatic surgery. The primary endpoint was clinically relevant postoperative pancreatic fistula. Secondary endpoints comprised perioperative outcome and pancreatic function and quality of life measured at 6 and 12 months of follow-up. RESULTS: From May 2011 to December 2012, 440 patients were randomized, and 320 were included in the intention-to-treat analysis. There was no significant difference in the rate of grade B/C fistula after PG versus PJ (20% vs 22%, P = 0.617). The overall incidence of grade B/C fistula was 21%, and the in-hospital mortality was 6%. Multivariate analysis of the primary endpoint disclosed soft pancreatic texture (odds ratio: 2.1, P = 0.016) as the only independent risk factor. Compared with PJ, PG was associated with an increased rate of grade A/B bleeding events, perioperative stroke, less enzyme supplementation at 6 months, and improved results in some quality of life parameters. CONCLUSIONS: The rate of grade B/C fistula after PG versus PJ was not different. There were more postoperative bleeding events with PG. Perioperative morbidity and mortality of pancreatoduodenectomy seem to be underestimated, even in the high-volume center setting.

N(1520) 3/2(-) helicity amplitudes from an energy-independent multipole analysis based on new polarization data on photoproduction of neutral pions.

New data on the polarization observables T, P, and H for the reaction γp→pπ(0) are reported. The results are extracted from azimuthal asymmetries when a transversely polarized butanol target and a linearly polarized photon beam are used. The data were taken at the Bonn electron stretcher accelerator ELSA using the CBELSA/TAPS detector. These and earlier data are used to perform a truncated energy-independent partial wave analysis in sliced-energy bins. This energy-independent analysis is compared to the results from energy-dependent partial wave analyses.

First measurement of the helicity asymmetry for γp → pπ0 in the resonance region.

The first measurement of the helicity dependence of the photoproduction cross section of single neutral pions off protons is reported for photon energies from 600 to 2300 MeV, covering nearly the full solid angle. The data are compared to predictions from the SAID, MAID, and BnGa partial wave analyses. Strikingly large differences between data and predictions are observed, which are traced to differences in the helicity amplitudes of well-known and established resonances. Precise values for the helicity amplitudes of several resonances are reported.

Haematological parameters do senesce in the wild: evidence from different populations of a long-lived mammal.

Increasing evidence of senescence has been reported from long-term studies of wild populations. However, most studies have focused on life-history traits like survival, reproduction or body mass, generally from a single intensively monitored population. However, variation in the intensity of senescence across populations, and to a lesser extent between sexes, is still poorly understood. In addition, the pattern of age-specific changes in haematological parameters remains virtually unknown to date for any population of vertebrate living in the wild. Using repeated blood samples collected from known-aged (2-15 years of age) roe deer (Capreolus capreolus) from two populations facing highly different environmental conditions, we filled the gap. In particular, we investigated age-specific changes in haematocrit, albumin and creatinine. We reported clear evidence of senescence in all haematological parameters. Moreover, senescence patterns differed between sexes and populations. The rate of senescence was higher in males than in females for haematocrit with no site difference. On the other hand, the rate of senescence in creatinine was higher at Trois Fontaines than at Chizé with no sex difference. Our findings provide a first demonstration of age-specific declines in haematological parameters in wild populations of large herbivores and show that the process of senescence in vertebrates is not restricted to body mass or fitness components. We also demonstrate that the senescence pattern of haematological parameters is context dependent and varies both between sexes and according to environmental conditions.

Technical feasibility of liver transplantation without cold storage.

PURPOSE: The success of liver transplantation (LT) is accompanied by an increased need for organs. The wider use of older donors and marginal organs with risk factors such as steatosis has lead to a new interest to improve the outcome with marginal organs. We herewith report a novel technique for LT with in situ preparation and immediate warm-ischemia liver transplantation (WI-LT). The aim of our study was to demonstrate the technical feasibility and report the transplant course. METHODS: Six patients underwent WI-LT at our institution. Hepatectomies during procurement and LT were both performed in parallel by different surgical teams. Technical factors and postoperative allograft function were analyzed. RESULTS: All six WI-LTs were performed without intraoperative complications with a mean warm-ischemia time (WIT) of 29.0 min. No patient developed primary non-function or required retransplantation. Mean alanine aminotransferase (194.0 ± 170.4 U/l) and aspartate aminotransferase (316.3 ± 222.1 U/l) values on the first postoperative day were low, indicating a low ischemia/reperfusion injury and an excellent liver function. CONCLUSIONS: These results demonstrate that WI-LT is a safe and technically feasible approach for LT with possibly reduced IRI and an excellent postoperative allograft quality. WI-LT may therefore be considered in individual patients especially with extended criteria donors to eventually improve postoperative allograft quality.

Performance of commercial SARS-CoV-2 wild-type and Omicron BA.1 antibody assays compared with pseudovirus neutralization tests.

BACKGROUND: Commercially available ELISA-based antibody tests are used to approximate vaccination success against SARS-CoV-2 in at-risk patients, but it is unclear whether they correlate with neutralization of the Omicron variant. METHODS: 269 serum samples of a cohort of 44 non-immunosuppressed participants and 65 MTX-treated rheumatic patients taken before and after COVID-19 booster vaccinations were measured using COVID-19 antibody testing systems with wild-type and Omicron BA.1 antigens developed by three different manufacturers (surrogate virus neutralization test cPass, and binding antibody tests QuantiVac and SeraSpot), as well as with a pseudovirus neutralization test (pVNT). The pVNT was considered the gold standard for determining the presence and level of anti-SARS-CoV-2 antibodies. RESULTS: All three wild-type ELISAs showed excellent test performance compared with wild-type neutralization in pVNT. However, out of 56 samples without Omicron BA.1 neutralization in pVNT, 71.4% showed positive results in at least one and 28.6% in all three wild-type ELISAs at the manufacturer-defined cut-offs. Omicron ELISAs showed either decreased specificity (57.1% and 55.4% for binding ELISAs) or sensitivity (51.2% in cPass) compared to Omicron neutralization in pVNT. The proportion of any false positive results among all samples decreased from 26.5% before to 3.2% after booster vaccination, however binding antibody test specificities remained below 70%. CONCLUSIONS: We found a poorer test performance of new Omicron antibody test systems compared to wild-type tests in detecting neutralizing antibodies against the corresponding SARS-CoV-2 variants. Decisions for booster vaccination or passive immunization of at-risk patients should not be based solely on antibody test results.

Well-established nucleon resonances revisited by double-polarization measurements.

The first measurement is reported of the double-polarization observable G in the photoproduction of neutral pions off protons, covering the photon energy range from 620 to 1120 MeV and the full solid angle. G describes the correlation between the photon polarization plane and the scattering plane for protons polarized along the direction of the incoming photon. The observable is highly sensitive to contributions from baryon resonances. The new results are compared to the predictions from SAID, MAID, and BnGa partial wave analyses. In spite of the long-lasting efforts to understand γp→pπ(0) as the simplest photoproduction reaction, surprisingly large differences between the new data and the latest predictions are observed which are traced to different contributions of the N(1535) resonance with spin parity J(P)=1/2(-) and N(1520) with J(P)=3/2(-). In the third resonance region, where N(1680) with J(P)=5/2(+) production dominates, the new data are reasonably close to the predictions.

Management and outcomes of haemorrhage after pancreatogastrostomy versus pancreatojejunostomy.

BACKGROUND: Postpancreatectomy haemorrhage (PPH) is a major cause of morbidity and mortality after pancreaticoduodenectomy (PD). It remains unclear whether performance of a pancreatogastrostomy (PG) instead of a pancreatojejunostomy (PJ) improves outcomes owing to better endoscopic accessibility. METHODS: A large retrospective analysis was undertaken to compare outcomes of PPH, depending on whether a PG or PJ was performed. The primary outcome was the rate of successful endoscopy. A secondary outcome was the therapeutic success after adding surgery. RESULTS: Of 944 patients who had a PD, 8·4 per cent developed PPH. Endoscopy was the primary intervention in 21 (81 per cent) of 26 patients with a PG and 34 (64 per cent) of 53 with a PJ; it identified the bleeding site in 35 and 25 per cent respectively (P = 0·347). Successful endoscopic treatment was more common in the PG group (31 versus 9 per cent; P = 0·026). Surgery was performed for PPH in 15 patients (58 per cent) with a PG and 35 (66 per cent) with a PJ (P = 0·470). The majority of haemorrhages that required surgery were non-anastomotic intra-abdominal haemorrhages (12 of 15 versus 21 of 35; P = 0·171). Endoscopic or conservative treatment for PPH was successful in 42 per cent of patients with a PG and 32 per cent with a PJ (P = 0·520). The success rate increased to 85 and 91 per cent respectively when surgery was included in the algorithm (P = 0·467). CONCLUSION: The type of pancreatic anastomosis and its inherent effect on endoscopic accessibility had very little impact on the outcome of PPH. This was because haemorrhage frequently occurred from intra-abdominal or non-anastomotic intraluminal lesions.

[Prevalence of SARS-CoV-2 in children from a cohort of 2192 patients]. / Prävalenz von SARS-CoV-2 bei Kindern in einer Kohorte von 2192 Patienten.

BACKGROUND: As of 18 June 2020 a total of 187,764 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections were reported in Germany and of these 6.9% were under the age of 19 years. There were initial indications that children are often asymptomatic and show a milder clinical course. OBJECTIVE: The aim of this study was to gain information on the prevalence of SARS-CoV­2 infections in a pediatric cohort. MATERIAL AND METHODS: Between 13 March and 18 June 2020 all children from whom a smear for SARS-CoV­2 was taken either to rule out an infection or as a suspected case were included. Data were collected on standardized patient record sheets. The analysis of data was anonymized and retrospective. RESULTS: During the given period 2192 children were investigated and 37 patients tested positive (1.7%) for SARS-CoV­2. Of these 36/37 were suspected cases and 28/37 were symptomatic. The leading symptoms were dry cough, runny nose and fever and three children had to be hospitalized. None showed a difficult course of the disease. Among those tested 505 were patients at risk due to an underlying chronic disease, 3 of whom (0.6%) were tested positive with an asymptomatic or mild course. CONCLUSION: We can confirm the first data showing that children and adolescents often have an asymptomatic or mild clinical course of infection or disease. We found no evidence of a high grey area of SARS-CoV­2 infections in this regional pediatric cohort.

Comparative study of carotenoids, catalase and radical formation in human and animal skin.

Animal skin is widely used in dermatological free radical research. Porcine ear skin is a well-studied substitute for human skin. The use of bovine udder skin is rare but its high carotenoid content makes it particularly appropriate for studying the redox state of the skin. Yet, information on the suitability of animal skin for the study of external hazard effects on the redox state of human skin has been lacking. In this study, we investigated the activity of the antioxidant enzyme catalase and the carotenoid content defining the redox status as well as UV-induced radical formation of human, porcine ear and bovine udder skin ex vivo. In human skin only low levels of radical formation were detected following UV irradiation, whereas bovine skin contains the highest amount of carotenoids but the lowest amount of catalase. Porcine ear skin does not exhibit a carotenoid signal but its catalase activity is close to human skin. Therefore, radical formation can neither be correlated to the amount of catalase nor to the amount of carotenoids in the skin. All skin types can be used for electron paramagnetic resonance-based detection of radicals, but porcine skin was found to be the most suitable type.

A cavity optomechanical locking scheme based on the optical spring effect.

We present a novel locking scheme for active length-stabilization and frequency detuning of a cavity optomechanical device based on the optical spring effect. The error signal is generated by utilizing the position measurement of a thermally driven intra-cavity nanomechanical device and employing its detuning-dependent frequency shift caused by the dispersive coupling to the cavity field. The scheme neither requires external modulation of the laser or the cavity nor does it demand for additional error signal readout, rendering its technical implementation rather simple for a large variety of existing optomechanical devices. Specifically, for large-linewidth microcavities or in situations where other locking schemes appear unfavorable conceptually or are hard to realize technically, the optical spring lock represents a potential alternative for stabilizing the cavity length. We explain the functional principle of the lock and characterize its performance in terms of bandwidth and gain profile.

Precision measurement of the neutral pion lifetime.

The explicit breaking of the axial symmetry by quantum fluctuations gives rise to the so-called axial anomaly. This phenomenon is solely responsible for the decay of the neutral pion π0 into two photons (γγ), leading to its unusually short lifetime. We precisely measured the decay width Γ of the [Formula: see text] process. The differential cross sections for π0 photoproduction at forward angles were measured on two targets, carbon-12 and silicon-28, yielding [Formula: see text], where stat. denotes the statistical uncertainty and syst. the systematic uncertainty. We combined the results of this and an earlier experiment to generate a weighted average of [Formula: see text] Our final result has a total uncertainty of 1.50% and confirms the prediction based on the chiral anomaly in quantum chromodynamics.