Analysis of acid-stressed Bacillus cereus reveals a major oxidative response and inactivation-associated radical formation

Acid stress resistance of the food-borne human pathogen Bacillus cereus may contribute to its survival in acidic environments, such as encountered in soil, food and the human gastrointestinal tract. The acid stress responses of B. cereus strains ATCC 14579 and ATCC 10987 were analysed in aerobically grown cultures acidified to pH values ranging from pH 5.4 to pH 4.4 with HCI. Comparative phenotype and transcriptome analyses revealed three acid stressinduced responses in this pH range: growth rate reduction, growth arrest and loss of viability. These physiological responses showed to be associated with metabolic shifts and the induction of general stress response mechanisms with a major oxidative component, including upregulation of catalases and superoxide dismutases. Flow cytometry analysis in combination with the hydroxyl (OH center dot) and peroxynitrite (ONOO-)-specific fluorescent probe 3'-(phydroxyphenyl) fluorescein (HPF) showed excessive radicals to be formed in both B. cereus strains in bactericidal conditions only. Our study shows that radicals can indicate acid-induced malfunctioning of cellular processes that lead to cell death

Changes in perceived stress and lifestyle behaviors in response to the COVID-19 pandemic in The Netherlands:An online longitudinal survey study

The COVID-19 pandemic has substantial implications for physical and mental wellbeing. This study investigated changes, over time, in lifestyle behaviors and perceived stress during the initial phase of the pandemic and associations with COVID-19 symptoms, in the Dutch general population. An online longitudinal survey study was performed with pre-lockdown measurements in February, and subsequently in April and June 2020 (n = 259, mean age 59 ± 14 years, 59% women). Self-report questionnaires were used to assess weight, diet quality, physical activity, alcohol intake, and smoking. Perceived stress was measured using the validated perceived stress scale (PSS-10). The presence of COVID-19 symptoms (yes/no) was defined as fever, or >3 of the following symptoms: weakness/tiredness, muscle ache, dry cough, loss of smell/taste, and breathing difficulties. Data were analyzed using linear mixed models, adjusted for age, sex, educational level, marital status and (change in) employment status. Minimal increases over time were observed in alcohol intake (0.6 ± 0.7 to 0.7 ± 1.1 glasses/day, p = 0.001) and smoking (9.5 ± 8.7 to 10.9 ± 9.4 cigarettes/day among 10% smokers, p = 0.03), but other lifestyle behaviors remained stable. In April 2020, 15% reported COVID-19-related symptoms, and in June 2020, this was 10%. The presence of COVID-19 symptoms was associated with increased perceived stress (p interaction = 0.003) and increased alcohol consumption (p interaction = 0.03) over time. In conclusion, in this prospective study, COVID-19 symptoms were associated with increases in perceived stress and alcohol consumption. Future research on biopsychosocial determinants and underlying mechanisms of lifestyle changes, as a response to the COVID-19 pandemic, is needed

The impact of treatment, socio-demographic and clinical characteristics on health-related quality of life among Hodgkin’s and non-Hodgkin’s lymphoma survivors: a systematic review

Cancer survivors are at risk of experiencing adverse physical and psychosocial effects of their cancer and its treatment. Both Hodgkin’s lymphoma (HL) and non-Hodgkin’s lymphoma (NHL) survivors face problems that can affect their health-related quality of life (HRQoL). The authors systematically reviewed the literature on HRQoL among HL and NHL survivors. A PubMed and PsychINFO literature search for original articles published until May 2011 was performed. Twenty-four articles, which met the predefined inclusion criteria, were subjected to a quality checklist. HL survivors showed the most problems in (role) physical, social and cognitive functioning, general health, fatigue and financial problems. In addition, HL survivors treated with a combination of therapies, with older age and female sex reported worse HRQoL. NHL survivors showed the most problems in physical functioning, appetite loss, vitality and financial problems. Having had chemotherapy was negatively associated with HRQoL, but no differences in chemotherapy regimens were found. Furthermore, in NHL survivors not meeting public exercise guidelines, HRQoL is low but can be improved with more exercise. More research on the longitudinal comparison between HL and NHL survivors and healthy controls should be performed in order to better understand the long-term (side) effects of treatment on HRQoL and possibilities to alleviate these

K–Te photocathodes: A new electron source for photoinjectors

K–Te photocathodes deposited on a Mo substrate have been successfully used as an electron source in the free electron laser of University of Twente. Long lifetimes have been measured: after more than 20 h of operation in the accelerator a K–Te cathode with 4.75% initial quantum efficiency still displays a 1.1% quantum efficiency at 259 nm. Moreover, the quantum efficiency of this cathode versus operation time can be fitted by an exponential decay curve, which saturates asymptotically to a 1.03% value, suggesting that a quantum efficiency close to 1% could be sustained for very long operation times. Films degraded by use can be recovered to a quantum efficiency which is close to the initial value, by heating the substrate at temperatures between 100 and 330 °C. A new procedure to obtain K–Te cathodes with high (up to 11%) quantum efficiencies is described

Correlation between surface reconstruction and polytypism in InAs nanowire selective area epitaxy

Themechanism of widely observed intermixing of wurtzite and zinc-blende crystal structures in InAs nanowire (NW) grown by selective area epitaxy (SAE) is studied. We demonstrate that the crystal structure in InAs NW grown by SAE can be controlled using basic growth parameters, and wurtzitelike InAs NWs are achieved.We link the polytypic InAs NWs SAE to the reconstruction of the growth front (111)B surface. Surface reconstruction study of InAs (111) substrate and the following homoepitaxy experiment suggest that (111) planar defect nucleation is related to the (1 × 1) reconstruction of InAs (111)B surface. In order to reveal it more clearly, a model is presented to correlate growth temperature and arsenic partial pressure with InAs NW crystal structure. This model considers the transition between (1 × 1) and (2 × 2) surface reconstructions in the frame of adatom atoms adsorption/desorption, and the polytypism is thus linked to reconstruction quantitatively. The experimental data fit well with the model, which highly suggests that surface reconstruction plays an important role in the polytypism phenomenon in InAs NWs SAE.https://doi.org/10.1103/PhysRevMaterials.1.074603Peer Reviewe

ESD characterization of planar InGaAs devices

We present a comprehensive study of ESD reliability (TLP) on planar nMOSFETs with In0.53Ga0.47As as the channel material. Two types of traps are found during ESD stress. They are formed through independent mechanisms: transient Ef-lowering induced pre-existing e-traps discharging in the gate stack and hot hole induced e-traps generation through impact ionization in the InP buffer. These two types of traps explain the observed walk-out of off-state channel leakage current as well as the two-stage current conduction phenomena in the TLP measurement. The generated e-traps are permanent and can introduce detrimental conduction current harmful to the device performance. By properly selecting the buffer material, these defects can be removed

The CAT Imaging Telescope for Very-High-Energy Gamma-Ray Astronomy

The CAT (Cherenkov Array at Themis) imaging telescope, equipped with a very-high-definition camera (546 fast phototubes with 0.12 degrees spacing surrounded by 54 larger tubes in two guard rings) started operation in Autumn 1996 on the site of the former solar plant Themis (France). Using the atmospheric Cherenkov technique, it detects and identifies very high energy gamma-rays in the range 250 GeV to a few tens of TeV. The instrument, which has detected three sources (Crab nebula, Mrk 421 and Mrk 501), is described in detail.Comment: 24 pages, 15 figures. submitted to Elsevier Preprin