Graphene-based charge sensors

We discuss graphene nanoribbon-based charge sensors and focus on their functionality in the presence of external magnetic fields and high frequency pulses applied to a nearby gate electrode. The charge detectors work well with in-plane magnetic fields of up to 7 T and pulse frequencies of up to 20 MHz. By analyzing the step height in the charge detector's current at individual charging events in a nearby quantum dot, we determine the ideal operation conditions with respect to the applied charge detector bias. Average charge sensitivities of 1.3 × 10(-3)e Hz(-1/2) can be achieved. Additionally, we investigate the back action of the charge detector current on the quantum transport through a nearby quantum dot. By varying the charge detector bias from 0 to 4.5 mV, we can increase the Coulomb peak currents measured at the quantum dot by a factor of around 400. Furthermore, we can completely lift the Coulomb blockade in the quantum dot.

A Web-based planning support tool for sediment management in a meso-scale river basin in Western Central Brazil

In scope of an IWRM concept for the Federal District, Western Central Brazil we developed a planning support tool, which enables non-experts to test the effects of land-use and land-cover change (LULCC) on landscape processes and landscape functions (LPF) related to sediment generation and retention. For this purpose we developed the web-based tool Letsmap do Brasil. The tool has two principal layers. The upper layer contains information on land use and its effect on LPF, i.e. sediment retention, runoff control, nitrogen loss control and agronomic value. The parameterized relation between land use and LPF is the core of the whole system. For each LPF a value specific to land use has been assigned. A second layer contains information on landscape properties and potentials (LPP), e.g. potential for sediment input in river networks and runoff potential. By linking land use and LPPs the system provides a spatially explicit assessment of effects of LULCC on landscape processes and functions (LPF). Letsmap do Brasil might have two major purposes. (1) It will support decision-making in river basin management and sediment management. By creating their own land-use/cover pattern non-expert users are enabled to test effects of LULCC on LPFs. (2) It will support and train non-experts to participate in decision processes in land-use planning. Because of its high adaptability, transparency, and simple handling Letsmap do Brasil might be used as tool in river basin management and land-use planning.

Epidemiology of Staphylococcus aureus blood and skin and soft tissue infections in the US military health system, 2005-2010

CONTEXT

Rates of hospital-onset methicillin-resistant Staphylococcus aureus (MRSA) infections are reported as decreasing, but recent rates of community-onset S. aureus infections are less known.

OBJECTIVES

To characterize the overall and annual incidence rates of community-onset and hospital-onset S. aureus bacteremia and skin and soft tissue infections (SSTIs) in a national health care system and to evaluate trends in the incidence rates of S. aureus bacteremia and SSTIs and the proportion due to MRSA.

DESIGN, SETTING, AND PARTICIPANTS

Observational study of all Department of Defense TRICARE beneficiaries from January 2005 through December 2010. Medical record databases were used to identify and classify all annual first-positive S. aureus blood and wound or abscess cultures as methicillin-susceptible S. aureus or MRSA, and as community-onset or hospital-onset infections (isolates collected >3 days after hospital admission).

MAIN OUTCOME MEASURES

Unadjusted incidence rates per 100,000 person-years of observation, the proportion of infections that was due to MRSA, and annual trends for 2005 through 2010 (examined using the Spearman rank correlation test or the Mantel-Haenszel χ2 test for linear trend).

RESULTS

During 56 million person-years (nonactive duty: 47 million person-years; active duty: 9 million person-years), there were 2643 blood and 80,281 wound or abscess annual first-positive S. aureus cultures. Annual incidence rates varied from 3.6 to 6.0 per 100,000 person-years for S. aureus bacteremia and 122.7 to 168.9 per 100,000 person-years for S. aureus SSTIs. The annual incidence rates for community-onset MRSA bacteremia decreased from 1.7 per 100,000 person-years (95% CI, 1.5-2.0 per 100,000 person-years) in 2005 to 1.2 per 100,000 person-years (95% CI, 0.9-1.4 per 100,000 person-years) in 2010 (P = .005 for trend). The annual incidence rates for hospital-onset MRSA bacteremia also decreased from 0.7 per 100,000 person-years (95% CI, 0.6-0.9 per 100,000 person-years) in 2005 to 0.4 per 100,000 person-years (95% CI, 0.3-0.5 per 100,000 person-years) in 2010 (P = .005 for trend). Concurrently, the proportion of community-onset SSTI due to MRSA peaked at 62% in 2006 before decreasing annually to 52% in 2010 (P < .001 for trend).

CONCLUSION

In the Department of Defense population consisting of men and women of all ages from across the United States, the rates of both community-onset and hospital-onset MRSA bacteremia decreased in parallel, while the proportion of community-onset SSTIs due to MRSA has more recently declined.

[Conversion of a retrograde access to an antegrade access for bilateral femorocrural intervention in one session]

PURPOSE

Evaluation of the feasibility as well as the success and complication rates of a change of access direction in patients with PAOD for bilateral intervention.

MATERIALS AND METHODS

Over the course of one year, 239 patients referred to our department for intervention of the iliac and femorocrural vessels were evaluated for an ipsilateral change of access direction. In 38 patients (16%), the symptoms indicated a bilateral femorocrural intervention. Three patients (8%) had to be excluded due to elevated creatinine level. In the remaining 35 patients, an attempt was made to change the cross-over access to an antegrade access in the same session. The procedure was accomplished by drawing a sidewinder catheter in the ipsilateral CIA, pushing a hydrophilic guide wire into the SFA and repositioning the sheath. Sonographic and clinical controls followed the next day.

RESULTS

In 32 patients (91%), the procedure was successful, and in 3 cases (9%), it failed. One major hematoma (3%), which could be treated conservatively, occurred. In 2 cases (6%) pseudoaneurysms developed and were treated by compression or thrombin injection. 3 minor hematomas (9%) were documented. In one patient (3%) a stroke occurred during the intervention after a brain stem infarction some weeks before, which could not be related to the intervention (total rate of minor complications 9%, major complications 12%).

CONCLUSION

The bilateral intervention of femorocrural vessels in one session by changing the access direction ipsilaterally is feasible and associated with acceptable complication rates. It offers the opportunity to optimize endovascular therapy economically.

Pediatric overweight prevention through a parent training program for 2-4 year old Latino children

BACKGROUND

Latino preschool children in the United States are at high risk for obesity. The objective of this study was to measure over a one-year period whether a parent training based on social learning theory combined with evidence-based interventions to promote optimal nutrition and physical activity will reduce the upward trend of BMI z-scores in groups of 2–4 year old Latino children living in low-income households.

METHODS

Seven weekly classes with 2 booster classes were delivered to low-income Latino parents with 2–4 year old children. A randomized controlled pilot study evaluated the effectiveness of the intervention that contrasts 61 children whose parents were randomized to receive Parent Training (PT) with 60 Wait-list (WL) subjects. Forty subjects did not attend the one-year follow up assessment, resulting in 81 subjects who have measurements for both baseline and one-year follow up assessments. To adjust for differential dropout rates and missing observations, imputation of missing data was done using a carefully constructed model that included relevant independent variables.

RESULTS

There were no significant subject differences between groups at baseline for family characteristics and BMI categories for child and parent. Children in the intervention group decreased their BMI z-scores significantly on average by .20 (SE= .08) compared to children in the control group who increased z scores on average by .04 (SE=.09) at one year (P<.05).

CONCLUSIONS

Parent training is effective to reduce the risk of overweight in preschool Latino children living in low-income households. The findings need to be examined in a larger sample of children.

Estimating the time needed for induction of anaesthesia and its importance in balancing anaesthetists' and surgeons' waiting times around the start of surgery

After the anaesthetist has induced anaesthesia, it is desirable that the surgeon is present and ready to start surgery, otherwise the team needs to wait for the surgeon. From another perspective, however, the surgeon does not necessarily wish to be present from the start of induction, since that process can take a variable time and the surgeon might be otherwise occupied in productive activity rather than waiting for the patient to be ready. Waiting times in the morning can therefore be a source of constant friction between anaesthetists and surgeons. In this prospective study we used the data from 718 first cases of the day, during a 4-week study period at two university hospitals, to develop a simple spreadsheet-based method to analyse the interaction of anaesthesia and surgical start time, anaesthesia technique and the probability of waiting time for anaesthetist or surgeon, respectively. This method can be used to determine the best surgical or anaesthesia start time for each case, so that the waiting time for anaesthetists and surgeons can be minimised.

Thrombophilia in patients with chronic venous leg ulcers-a study on patients with or without post-thrombotic syndrome

BACKGROUND

Chronic venous leg ulcers (CVU) cause considerable burden of disease for the patients as well as enormous costs for health care systems. The pathophysiology of CVU is complex and not entirely understood. So far reliable pathogenic and/or prognostic parameters have not been identified.

OBJECTIVES

We studied the role of thrombophilia in patients referred to a University dermatology department for treatment of CVU.

PATIENTS AND METHODS

A cohort of 310 patients with active chronic venous leg ulcers (CEAP 6) was stratified into two comparably large groups according to the presence or absence of post-thrombotic syndrome (PTS+; PTS-) as determined using duplex scan and/or phlebography. In addition, several thrombophilia parameters were assessed.

RESULTS

The prevalence of protein S deficiency and factor V Leiden mutation was significantly higher in PTS+ patients compared with the PTS- group. However, patients in both subgroups revealed high prevalences of thrombophilia (antithrombin deficiency, protein C deficiency, protein S deficiency, activated protein C resistance, factor V mutation or elevated homocysteine).

CONCLUSION

Based on these data, it is conceivable that thrombophilia contributes to the pathogenesis of CVU, possibly through induction of microcirculatory dysregulations.

ARTERIAL HYPERTENSION IN RATS : II. EFFECTS ON THE KIDNEYS

1. When rats developed cardiac hypertrophy or elevation of blood pressure as a result of one of several methods designed to bring about arterial hypertension, renal vascular disease occurred frequently. 2. When injury to one kidney was followed by cardiac hypertrophy or elevation of blood pressure, vascular lesions were found with considerable regularity in the opposite one, as well as in the one injured. 3. Renal lesions rarely occurred in the absence of cardiac hypertrophy or elevated blood pressure. 4. Renal vascular lesions in rats are occasioned, therefore, by injury to one kidney and are usually associated with, and dependent on, the presence of arterial hypertension.

Effects of a school feeding intervention on school attendance rates among elementary schoolchildren in rural Kenya

OBJECTIVE

A randomized controlled school feeding intervention offered an opportunity to determine whether school feeding resulted in improved school attendance among elementary schoolchildren in a rural district of Kenya.

METHODS

Twelve schools with a total of 554 children in the 1998 first-grade cohort were randomly assigned to four research groups, three of which received a fortified local staple-based snack (Githeri meal) at morning recess. The groups--designated as Meat-Githeri, Milk-Githeri, and Energy-Githeri--received a recess meal that provided 240 kcal in the first school year and 313 kcal for the remainder of study period. The intervention study covered the second school term of 1998 through the second school term of 2000. Assessment for all indexed children included baseline assessment of anthropometric measures of height-for-weight, weight-for-age, and height-for-age, and socioeconomic status at baseline, as well as daily school attendance for each of the school terms. Analysis included descriptive statistics, partial correlations statistics, regression analysis, χ(2), and General Linear Model (GLM) repeated measures analysis. In all the analyses, P < 0.05 was used as the criterion of statistical significance.

RESULTS

Baseline regression analysis for the overall study sample population showed that age-dependent anthropometric measures of nutritional status were statistically significant predictors of school attendance rates. Partial correlation analysis evidenced a statistically significant positive association between baseline attendance rates and the measures of socioeconomic status and the age-dependent anthropometric measures. The intervention groups performed better than the control group on the repeated measure of school attendance.