Work function of few layer graphene covered nickel thin films measured with Kelvin probe force microscopy

Few layer graphene and graphite are simultaneously grown on a similar to 100 nm thick polycrystalline nickel film. The work function of few layer graphene/Ni is found to be 4.15 eV with a variation of 50 meV by local measurements with Kelvin probe force microscopy. This value is lower than the work function of free standing graphene due to peculiar electronic structure resulting from metal 3d-carbon 2p(pi) hybridization. (C) 2016 AIP Publishing LLC

An updated analysis of NN elastic scattering data to 1.6 GeV

An energy-dependent and set of single-energy partial-wave analyses of $NN$ elastic scattering data have been completed. The fit to 1.6~GeV has been supplemented with a low-energy analysis to 400 MeV. Using the low-energy fit, we study the sensitivity of our analysis to the choice of $\pi NN$ coupling constant. We also comment on the possibility of fitting $np$ data alone. These results are compared with those found in the recent Nijmegen analyses. (Figures may be obtained from the authors upon request.)Comment: 17 pages of text, VPI-CAPS-7/

Reduction in Phencyclidine Induced Sensorimotor Gating Deficits in the Rat Following Increased System Xc − Activity in the Medial Prefrontal Cortex

Rationale: Aspects of schizophrenia, including deficits in sensorimotor gating, have been linked to glutamate dysfunction and/or oxidative stress in the prefrontal cortex. System xc −, a cystine–glutamate antiporter, is a poorly understood mechanism that contributes to both cellular antioxidant capacity and glutamate homeostasis. Objectives: Our goal was to determine whether increased system xc − activity within the prefrontal cortex would normalize a rodent measure of sensorimotor gating. Methods: In situ hybridization was used to map messenger RNA (mRNA) expression of xCT, the active subunit of system xc −, in the prefrontal cortex. Prepulse inhibition was used to measure sensorimotor gating; deficits in prepulse inhibition were produced using phencyclidine (0.3–3 mg/kg, sc). N-Acetylcysteine (10–100 μM) and the system xc − inhibitor (S)-4-carboxyphenylglycine (CPG, 0.5 μM) were used to increase and decrease system xc − activity, respectively. The uptake of 14C-cystine into tissue punches obtained from the prefrontal cortex was used to assay system xc − activity. Results: The expression of xCT mRNA in the prefrontal cortex was most prominent in a lateral band spanning primarily the prelimbic cortex. Although phencyclidine did not alter the uptake of 14C-cystine in prefrontal cortical tissue punches, intraprefrontal cortical infusion of N-acetylcysteine (10–100 μM) significantly reduced phencyclidine- (1.5 mg/kg, sc) induced deficits in prepulse inhibition. N-Acetylcysteine was without effect when coinfused with CPG (0.5 μM), indicating an involvement of system xc −. Conclusions: These results indicate that phencyclidine disrupts sensorimotor gating through system xc − independent mechanisms, but that increasing cystine–glutamate exchange in the prefrontal cortex is sufficient to reduce behavioral deficits produced by phencyclidine

Mechanical Dissipation in Silicon Flexures

The thermo-mechanical properties of silicon make it of significant interest as a possible material for mirror substrates and suspension elements for future long-baseline gravitational wave detectors. The mechanical dissipation in 92um thick single-crystal silicon cantilevers has been observed over the temperature range 85 K to 300 K, with dissipation approaching levels down to phi = 4.4E-7.Comment: 7 pages. Accepted by Phys Lett A, submitted for publication on 28 October 200

Dopant imaging of power semiconductor device cross sections

Several Scanning Probe Microscopy (SPM) methods allow to image dopant profiles in a range from 10(14) cm(-3) to 10(19) cm(-3) on semiconducting samples. In our work we present Scanning Capacitance Force Microscopy (SCFM) and Kelvin Probe Force Microscopy (KPFM) experiments performed on cross sections of silicon (Si) and silicon carbide (SiC) power devices and epitaxially grown calibration layers. The contact potential difference (CPD) shows under illumination a reduced influence on surface defect states. In addition results from numerical simulation of these microscope methods are discussed. (C) 2016 Elsevier B.V. All rights reserved

Post-acute sequelae after SARS-CoV-2 infection by viral variant and vaccination status: a multicenter cross-sectional study.

BACKGROUND Disentangling the effects of SARS-CoV-2 variants and vaccination on the occurrence of post-acute sequelae of SARS-CoV-2 (PASC) is crucial to estimate and reduce the burden of PASC. METHODS We performed a cross-sectional analysis (May/June 2022) within a prospective multicenter healthcare worker (HCW) cohort in North-Eastern Switzerland. HCW were stratified by viral variant and vaccination status at time of their first positive SARS-CoV-2 nasopharyngeal swab. HCW without positive swab and with negative serology served as controls. The sum of eighteen self-reported PASC symptoms was modeled with univariable and multivariable negative-binomial regression to analyse the association of mean symptom number with viral variant and vaccination status. RESULTS Among 2'912 participants (median age 44 years, 81.3% female), PASC symptoms were significantly more frequent after wild-type infection (estimated mean symptom number 1.12, p<0.001; median time since infection 18.3 months), after Alpha/Delta infection (0.67 symptoms, p<0.001; 6.5 months), and after Omicron BA.1 infections (0.52 symptoms, p=0.005; 3.1 months) compared to uninfected controls (0.39 symptoms). After Omicron BA.1 infection, the estimated mean symptom number was 0.36 for unvaccinated individuals, compared to 0.71 with 1-2 vaccinations (p=0.028) and 0.49 with ≥3 prior vaccinations (p=0.30). Adjusting for confounders, only wild-type (adjusted rate ratio [aRR] 2.81, 95% confidence interval [CI] 2.08-3.83) and Alpha/Delta infection (aRR 1.93, 95% CI 1.10-3.46) were significantly associated with the outcome. CONCLUSIONS Previous infection with pre-Omicron variants was the strongest risk factor for PASC symptoms among our HCW. Vaccination prior to Omicron BA.1 infection was not associated with a clear protective effect against PASC symptoms in this population

Impact of baseline SARS-CoV-2 antibody status on syndromic surveillance and the risk of subsequent COVID-19-a prospective multicenter cohort study.

BACKGROUND In a prospective healthcare worker (HCW) cohort, we assessed the risk of SARS-CoV-2 infection according to baseline serostatus. METHODS Baseline serologies were performed among HCW from 23 Swiss healthcare institutions between June and September 2020, before the second COVID-19 wave. Participants answered weekly electronic questionnaires covering information about nasopharyngeal swabs (PCR/rapid antigen tests) and symptoms compatible with coronavirus disease 2019 (COVID-19). Screening of symptomatic staff by nasopharyngeal swabs was routinely performed in participating facilities. We compared numbers of positive nasopharyngeal tests and occurrence of COVID-19 symptoms between HCW with and without anti-nucleocapsid antibodies. RESULTS A total of 4812 HCW participated, wherein 144 (3%) were seropositive at baseline. We analyzed 107,807 questionnaires with a median follow-up of 7.9 months. Median number of answered questionnaires was similar (24 vs. 23 per person, P = 0.83) between those with and without positive baseline serology. Among 2712 HCW with ≥ 1 SARS-CoV-2 test during follow-up, 3/67 (4.5%) seropositive individuals reported a positive result (one of whom asymptomatic), compared to 547/2645 (20.7%) seronegative participants, 12 of whom asymptomatic (risk ratio [RR] 0.22; 95% confidence interval [CI] 0.07 to 0.66). Seropositive HCWs less frequently reported impaired olfaction/taste (6/144, 4.2% vs. 588/4674, 12.6%, RR 0.33, 95% CI 0.15-0.73), chills (19/144, 13.2% vs. 1040/4674, 22.3%, RR 0.59, 95% CI 0.39-0.90), and limb/muscle pain (28/144, 19.4% vs. 1335/4674, 28.6%, RR 0.68 95% CI 0.49-0.95). Impaired olfaction/taste and limb/muscle pain also discriminated best between positive and negative SARS-CoV-2 results. CONCLUSIONS Having SARS-CoV-2 anti-nucleocapsid antibodies provides almost 80% protection against SARS-CoV-2 re-infection for a period of at least 8 months

Risk and symptoms of COVID-19 in health professionals according to baseline immune status and booster vaccination during the Delta and Omicron waves in Switzerland-A multicentre cohort study.

BACKGROUND Knowledge about protection conferred by previous Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and/or vaccination against emerging viral variants allows clinicians, epidemiologists, and health authorities to predict and reduce the future Coronavirus Disease 2019 (COVID-19) burden. We investigated the risk and symptoms of SARS-CoV-2 (re)infection and vaccine breakthrough infection during the Delta and Omicron waves, depending on baseline immune status and subsequent vaccinations. METHODS AND FINDINGS In this prospective, multicentre cohort performed between August 2020 and March 2022, we recruited hospital employees from ten acute/nonacute healthcare networks in Eastern/Northern Switzerland. We determined immune status in September 2021 based on serology and previous SARS-CoV-2 infections/vaccinations: Group N (no immunity); Group V (twice vaccinated, uninfected); Group I (infected, unvaccinated); Group H (hybrid: infected and ≥1 vaccination). Date and symptoms of (re)infections and subsequent (booster) vaccinations were recorded until March 2022. We compared the time to positive SARS-CoV-2 swab and number of symptoms according to immune status, viral variant (i.e., Delta-dominant before December 27, 2021; Omicron-dominant on/after this date), and subsequent vaccinations, adjusting for exposure/behavior variables. Among 2,595 participants (median follow-up 171 days), we observed 764 (29%) (re)infections, thereof 591 during the Omicron period. Compared to group N, the hazard ratio (HR) for (re)infection was 0.33 (95% confidence interval [CI] 0.22 to 0.50, p < 0.001) for V, 0.25 (95% CI 0.11 to 0.57, p = 0.001) for I, and 0.04 (95% CI 0.02 to 0.10, p < 0.001) for H in the Delta period. HRs substantially increased during the Omicron period for all groups; in multivariable analyses, only belonging to group H was associated with protection (adjusted HR [aHR] 0.52, 95% CI 0.35 to 0.77, p = 0.001); booster vaccination was associated with reduction of breakthrough infection risk in groups V (aHR 0.68, 95% CI 0.54 to 0.85, p = 0.001) and H (aHR 0.67, 95% CI 0.45 to 1.00, p = 0.048), largely observed in the early Omicron period. Group H (versus N, risk ratio (RR) 0.80, 95% CI 0.66 to 0.97, p = 0.021) and participants with booster vaccination (versus nonboosted, RR 0.79, 95% CI 0.71 to 0.88, p < 0.001) reported less symptoms during infection. Important limitations are that SARS-CoV-2 swab results were self-reported and that results on viral variants were inferred from the predominating strain circulating in the community at that time, rather than sequencing. CONCLUSIONS Our data suggest that hybrid immunity and booster vaccination are associated with a reduced risk and reduced symptom number of SARS-CoV-2 infection during Delta- and Omicron-dominant periods. For previously noninfected individuals, booster vaccination might reduce the risk of symptomatic Omicron infection, although this benefit seems to wane over time

Acute upper airway failure and mediastinal emphysema following a wire-guided percutaneous cricothyrotomy in a patient with severe maxillofacial trauma

Contains fulltext : 69538.pdf (publisher's version ) (Open Access)BACKGROUND: In the presence of severe maxillofacial trauma, management of the airway is important because this condition poses a significant threat to airway patency. That securing the airway is not always straightforward is described and illustrated in this paper. CASE: We present the case of a 23-year-old patient who sustained severe maxillofacial injury for which airway control was necessary. A wire-guided percutaneous dilation cricothyrotomy was performed, which was most probably the cause of an acute loss of airway patency. The literature regarding the role of percutaneous techniques in an elective and emergency setting is reviewed

Gamma (γ) tocopherol upregulates peroxisome proliferator activated receptor (PPAR) gamma (γ) expression in SW 480 human colon cancer cell lines

BACKGROUND: Tocopherols are lipid soluble antioxidants that exist as eight structurally different isoforms. The intake of γ-tocopherol is higher than α-tocopherol in the average US diet. The clinical results of the effects of vitamin E as a cancer preventive agent have been inconsistent. All published clinical trials with vitamin E have used α-tocopherol. Recent epidemiological, experimental and molecular studies suggest that γ-tocopherol may be a more potent chemopreventive form of vitamin E compared to the more-studied α-tocopherol. γ-Tocopherol exhibits differences in its ability to detoxify nitrogen dioxide, growth inhibitory effects on selected cancer cell lines, inhibition of neoplastic transformation in embryonic fibroblasts, and inhibition of cyclooxygenase-2 (COX-2) activity in macrophages and epithelial cells. Peroxisome proliferator activator receptor γ (PPARγ) is a promising molecular target for colon cancer prevention. Upregulation of PPARγ activity is anticarcinogenic through its effects on downstream genes that affect cellular proliferation and apoptosis. The thiazolidine class of drugs are powerful PPARγ ligands. Vitamin E has structural similarity to the thiazolidine, troglitazone. In this investigation, we tested the effects of both α and γ tocopherol on the expression of PPARγ mRNA and protein in SW 480 colon cancer cell lines. We also measured the intracellular concentrations of vitamin E in SW 480 colon cancer cell lines. RESULTS: We have discovered that the α and γ isoforms of vitamin E upregulate PPARγ mRNA and protein expression in the SW480 colon cancer cell lines. γ-Tocopherol is a better modulator of PPARγ expression than α-tocopherol at the concentrations tested. Intracellular concentrations increased as the vitamin E concentration added to the media was increased. Further, γ-tocopherol-treated cells have higher intracellular tocopherol concentrations than those treated with the same concentrations of α-tocopherol. CONCLUSION: Our data suggest that both α and γ tocopherol can upregulate the expression of PPARγ which is considered an important molecular target for colon cancer chemoprevention. We show that the expression of PPARγ mRNA and protein are increased and these effects are more pronounced with γ-tocopherol. γ-Tocopherol's ability to upregulate PPARγ expression and achieve higher intracellular concentrations in the colonic tissue may be relevant to colon cancer prevention. We also show that the intracellular concentrations of γ-tocopherol are several fold higher than α-tocopherol. Further work on other colon cancer cell lines are required to quantitate differences in the ability of these forms of vitamin E to induce apoptosis, suppress cell proliferation and act as PPAR ligands as well as determine their effects in conjunction with other chemopreventive agents. Upregulation of PPARγ by the tocopherols and in particular by γ-tocopherol may have relevance not only to cancer prevention but also to the management of inflammatory and cardiovascular disorders