Precision high voltage divider for the KATRIN experiment

The Karlsruhe Tritium Neutrino Experiment (KATRIN) aims to determine the absolute mass of the electron antineutrino from a precise measurement of the tritium beta-spectrum near its endpoint at 18.6 keV with a sensitivity of 0.2 eV. KATRIN uses an electrostatic retardation spectrometer of MAC-E filter type for which it is crucial to monitor high voltages of up to 35 kV with a precision and long-term stability at the ppm level. Since devices capable of this precision are not commercially available, a new high voltage divider for direct voltages of up to 35 kV has been designed, following the new concept of the standard divider for direct voltages of up to 100 kV developed at the Physikalisch-Technische Bundesanstalt (PTB). The electrical and mechanical design of the divider, the screening procedure for the selection of the precision resistors, and the results of the investigation and calibration at PTB are reported here. During the latter, uncertainties at the low ppm level have been deduced for the new divider, thus qualifying it for the precision measurements of the KATRIN experiment.Comment: 22 pages, 12 figure

Treating Diabetes and Hypertension in the Obese Patient

Obesity is an independent risk factor for coronary heart disease and it is associated with insulin resistance, which contributes to the development of dyslipidemia, hypertension, and type 2 diabetes. The coexistence of hypertension and diabetes increases the risk for macrovascular and microvascular complications, predisposing patients to congestive heart failure, coronary heart disease, cerebral and peripheral vascular diseases, nephropathy, and retinopathy. In obese diabetic patients, body weight reduction, as well as metiformin therapy, increase insulin sensitivity and enhance blood pressure and glicemic control. Antihypertensive treatment in diabetic patients decreases cardiovascular mortality and delays the decline of the glomerular function. Pharmacological treatment should consider the effects of the antihypertensive agents on insulin sensitivity and lipid profile. Diuretics and b-blockers are reported to reduce insulin sensitivity, whereas calcium channel blockers are metabolically neutral and ACE inhibitors increase insulin sensitivity and confer additional renal and vascular protection to diabetic patients. Angiotensin II antagonists has shown similar effects.A obesidade é um fator de risco independente para doença coronariana. A resistência à insulina associada à obesidade contribui para o desenvolvimento de dislipidemia, hipertensão arterial e diabetes tipo 2. A coexistência de hipertensão e diabetes aumenta o risco para complicações micro e macrovasculares, predispondo os indivíduos à insuficiência cardíaca congestiva, doença coronariana e cerebrovascular, insuficiência arterial periférica, nefropatia e retinopatia. Em pacientes diabéticos obesos a redução do peso, bem como o uso de metiformina, melhoram a sensibilidade à insulina, o controle da glicemia e da pressão arterial. O tratamento anti-hipertensivo em diabéticos reduz a mortalidade cardiovascular e retarda o declínio da função glomerular. Deve-se considerar os efeitos dos agentes anti-hipertensivos sobre a sensibilidade à insulina e o perfil lipídico. Diuréticos e b-bloqueadores podem reduzir a sensibilidade à insulina, enquanto bloqueadores de canais de cálcio são metabolicamente neutros e os iECA aumentam a sensibilidade à insulina, além de conferir proteção adicional cardiovascular e renal para diabéticos. O bloqueio da angiotensina II tem mostrado benefícios semelhantes.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUNIFESP, EPMSciEL

Magnetization reversal of an individual exchange biased permalloy nanotube

We investigate the magnetization reversal mechanism in an individual permalloy (Py) nanotube (NT) using a hybrid magnetometer consisting of a nanometer-scale SQUID (nanoSQUID) and a cantilever torque sensor. The Py NT is affixed to the tip of a Si cantilever and positioned in order to optimally couple its stray flux into a Nb nanoSQUID. We are thus able to measure both the NT's volume magnetization by dynamic cantilever magnetometry and its stray flux using the nanoSQUID. We observe a training effect and temperature dependence in the magnetic hysteresis, suggesting an exchange bias. We find a low blocking temperature $T_B = 18 \pm 2$ K, indicating the presence of a thin antiferromagnetic native oxide, as confirmed by X-ray absorption spectroscopy on similar samples. Furthermore, we measure changes in the shape of the magnetic hysteresis as a function of temperature and increased training. These observations show that the presence of a thin exchange-coupled native oxide modifies the magnetization reversal process at low temperatures. Complementary information obtained via cantilever and nanoSQUID magnetometry allows us to conclude that, in the absence of exchange coupling, this reversal process is nucleated at the NT's ends and propagates along its length as predicted by theory.Comment: 8 pages, 4 figure

The curvature of semidirect product groups associated with two-component Hunter-Saxton systems

In this paper, we study two-component versions of the periodic Hunter-Saxton equation and its $\mu$-variant. Considering both equations as a geodesic flow on the semidirect product of the circle diffeomorphism group \Diff(\S) with a space of scalar functions on $\S$ we show that both equations are locally well-posed. The main result of the paper is that the sectional curvature associated with the 2HS is constant and positive and that 2$\mu$HS allows for a large subspace of positive sectional curvature. The issues of this paper are related to some of the results for 2CH and 2DP presented in [J. Escher, M. Kohlmann, and J. Lenells, J. Geom. Phys. 61 (2011), 436-452].Comment: 19 page

Superconducting quantum interference devices with submicron Nb/HfTi/Nb junctions for investigation of small magnetic particles

We investigated, at temperature $4.2\,\mathrm{K}$, electric transport, flux noise and resulting spin sensitivity of miniaturized Nb direct current superconducting quantum interference devices (SQUIDs) based on submicron Josephson junctions with HfTi barriers. The SQUIDs are either of the magnetometer-type or gradiometric in layout. In the white noise regime, for the best magnetometer we obtain a flux noise $S_{\Phi}^{1/2}=250\,\mathrm{n}\Phi_0/\mathrm{Hz}^{1/2}$, corresponding to a spin sensitivity $S^{1/2}_\mu\,\ge\,29\,\mu_B/\mathrm{Hz}^{1/2}$. For the gradiometer we find $S_{\Phi}^{1/2}=300\,\mathrm{n}\Phi_0/\mathrm{Hz}^{1/2}$ and $S^{1/2}_\mu\,\ge\,44\,\mu_B/\mathrm{Hz}^{1/2}$. The devices can still be optimized with respect to flux noise and coupling between a magnetic particle and the SQUID, leaving room for further improvement towards single spin resolution.Comment: 4 pages, 3 figure

Hyperglycemia and nocturnal systolic blood pressure are associatedwith left ventricular hypertrophy and diastolic dysfunction in hypertensive diabetic patients

BACKGROUND: The aim of this study was to determine if hypertensive type 2 diabetic patients, when compared to patients with essential hypertension have an increased left ventricular mass index (LVMI) and a worse diastolic function, and if this fact would be related to 24-h pressoric levels changes. METHODS: Ninety-one hypertensive patients with type 2 diabetes mellitus (DM) (group-1 [G1]), 59 essential hypertensive patients (group-2 [G2]) and 26 healthy controls (group-3 [G3]) were submitted to 24-h Ambulatory Blood Pressure Monitoring (ABPM) and echocardiography (ECHO) with Doppler. We calculated an average of fasting blood glucose (AFBG) values of G1 from the previous 4.2 years and a glycemic control index (GCI) (percentual of FBG above 200 mg/dl). RESULTS: G1 and G2 did not differ on average of diurnal systolic and diastolic BP. However, G1 presented worse diastolic function and a higher average of nocturnal systolic BP (NSBP) and LVMI (NSBP = 132 ± 18 vs 124 ± 14 mmHg; P < 0.05 and LVMI = 103 ± 27 vs 89 ± 17 g/m(2); P < 0.05, respectively). In G1, LVMI correlated with NSBP (r = 0.37; P < 0.001) and GCI (r = 0.29; P < 0.05) while NSBP correlated with GCI (r = 0.27; P < 0.05) and AFBG (r = 0.30; P < 0.01). When G1 was divided in tertiles according to NSBP, the subgroup with NSBP≥140 mmHg showed a higher risk of LVH. Diabetics with NSBP≥140 mmHg and AFBG>165 mg/dl showed an additional risk of LVH (P < 0.05; odds ratio = 11). In multivariate regression, both GCI and NSBP were independent predictors of LVMI in G1. CONCLUSION: This study suggests that hyperglycemia and higher NSBP levels should be responsible for an increased prevalence of LVH in hypertensive patients with Type 2 DM

Scoring the EQ-HWB-S: can we do it without value sets? A non-parametric item response theory analysis

Background Only one pilot value set (UK) is currently available for the EQ Health and Wellbeing Instrument short version (EQ-HWB-S). As an alternative to preference-weighted scoring, we examined whether a level summary score (LSS) is appropriate for the EQ-HWB-S using Mokken scaling analyses. Methods Data from patients, carers and the general population collected during the developmental phase of the EQ-HWB-S in Australia, US and UK were used, noting 3 of 9 items have since undergone revision. EQ-HWB-S data fit was examined using R package Mokken scaling’s monotone homogeneity model, utilizing the automated item selection procedure (AISP) as well as Loevinger’s scaling coefficients for items and the scale (HS). Manifest monotonicity was assessed by examining whether the cumulative probability for responses at or above each response level did not decrease across the summary score. Results EQ-HWB-S data were available for 3340 respondents: US = 903, Australia = 514 and UK = 1923. Mean age was 50 ± 18 and 1841 (55%) were female. AISP placed all 9 items of the EQ-HWB-S on a single scale when the lower bound was set to < 0.448. Strong scalability (HS = 0.561) was found for the EQ-HWB-S as a single scale. Stronger scales were formed by separating the psychosocial items (n = 6, HS = 0.683) and physical sensation items (n = 3, HS = 0.713). No violations of monotonicity were found except for the items mobility and daily activities for the subgroups with long-term conditions and UK subjects, respectively. Discussion As EQ-HWB-S items formed a strong scale and subscales based on Mokken analysis, LSS is a promising weighting-free approach to scoring

Precipitation of Trichoderma reesei commercial cellulase preparations under standard enzymatic hydrolysis conditions for lignocelluloses

Comparative studies between commercial Trichoderma reesei cellulase preparations show that, depending on the preparation and loading, total protein precipitation can be as high as 30 % under standard hydrolysis conditions used for lignocellulosic materials. ATR-IR and SDS-PAGE data verify precipitates are protein-based and contain key cell wall hydrolyzing enzymes. Precipitation increased considerably with incubation temperature; roughly 50–150 % increase from 40 to 50 °C and 800 % greater at 60 °C. All of the reported protein losses translated into significant, and often drastic, losses in activity on related 4-nitrophenyl substrates. In addition, supplementation with the non-ionic surfactant PEG 6,000 decreased precipitation up to 80 % in 24 h precipitation levels. Protein precipitation is potentially substantial during enzymatic hydrolysis of lignocelluloses and should be accounted for during lignocellulose conversion process design, particularly when enzyme recycling is considered.This work was supported by the project "Demonstrating Industrial scale second generation bioethaol production-Kalundborg Cellulosic Ethanol Plant" under the EU FP7 framework program and the project "Development of improved second generation (2G) bioethanol technology to prepare for commercialization under the Danish Energy Technology and Demonstration Programme (EUDP)