An improved method for large-scale preparation of negatively and positively supercoiled plasmid DNA

A rigorous understanding of the biological function of superhelical tension in cellular DNA requires the development of new tools and model systems for study. To this end, an ethidium bromide–free method has been developed to prepare large quantities of either negatively or positively super-coiled plasmid DNA. The method is based upon the known effects of ionic strength on the direction of binding of DNA to an archaeal histone, rHMfB, with low and high salt concentrations leading to positive and negative DNA supercoiling, respectively. In addition to fully optimized conditions for large-scale (>500 µg) supercoiling reactions, the method is advantageous in that it avoids the use of mutagenic ethidium bromide, is applicable to chemically modified plasmid DNA substrates, and produces both positively and negatively supercoiled DNA using a single set of reagents.National Cancer Institute (U.S.) (NCI; grant no. CA072936)National Cancer Institute (U.S.) (NCI; grant no. CA110261)National Cancer Institute (U.S.) (NCI; grant no. CA103146)National Institute of Environmental Health Sciences (ES002109)National Defense Science and Engineering Graduate Fellowshi

Cryptosporidium, Enterocytozoon, and Cyclospora Infections in Pediatric and Adult Patients with Diarrhea in Tanzania.

Cryptosporidiosis, microsporidiosis, and cyclosporiasis were studied in four groups of Tanzanian inpatients: adults with AIDS-associated diarrhea, children with chronic diarrhea (of whom 23 of 59 were positive [+] for human immunodeficiency virus [HIV]), children with acute diarrhea (of whom 15 of 55 were HIV+), and HIV control children without diarrhea. Cryptosporidium was identified in specimens from 6/86 adults, 5/59 children with chronic diarrhea (3/5, HIV+), 7/55 children with acute diarrhea (0/7, HIV+), and 0/20 control children. Among children with acute diarrhea, 7/7 with cryptosporidiosis were malnourished, compared with 10/48 without cryptosporidiosis (P < .01). Enterocytozoon was identified in specimens from 3/86 adults, 2/59 children with chronic diarrhea (1 HIV+), 0/55 children with acute diarrhea, and 4/20 control children. All four controls were underweight (P < .01). Cyclospora was identified in specimens from one adult and one child with acute diarrhea (HIV-). Thus, Cryptosporidium was the most frequent and Cyclospora the least frequent pathogen identified. Cryptosporidium and Enterocytozoon were associated with malnutrition. Asymptomatic fecal shedding of Enterocytozoon in otherwise healthy, HIV children has not been described previously

De praktijk van toezicht in een neoliberaal tijdperk

Net als vele andere inspecties kreeg de Inspectie Sociale Zaken en Werkgelegenheid (ISZW) in de afgelopen jaren te maken met teruglopende middelen en de roep om zich beter te verantwoorden over de gehanteerde werkwijzen en resultaten. ISZW heeft getracht om aan deze verwachtingen tegemoet te komen door doelgerichter te werken – door middel van het delegeren van toezichtsverantwoordelijkheden en de aanscherping van sanctionering en handhaving – en door verantwoording af te leggen met behulp van risico-gestuurd toezicht. Delegeren In dit onderzoek staat de vraag centraal hoe inspecteurs die toezien op de naleving van de wet- en regelgeving rond arbeidsomstandigheden omgaan met de beleidsstrategie waarbij risico-gestuurd toezicht wordt gecombineerd met het delegeren van verantwoordelijkheden naar ondertoezichtgestelden en de aanscherping van handhaving en sanctionering. Komt de wijze waarop zij hun taken uitvoeren overeen met de strategie en het beleid van hun organisatie? Op basis van een analyse van het handhavingsbeleid, interviews met inspecteurs en observaties van inspecties is in kaart gebracht hoe ISZW invulling heeft gegeven aan het nieuwe beleid, welke veranderingen dit meebrengt voor het werk van inspecteurs en hoe zij in de praktijk met deze veranderingen omgaan. Innovaties Het onderzoek laat zien dat de wijze waarop inspecteurs in de praktijk toezicht houden, afwijkt van de uitgangspunten die aan het formele beleid ten grondslag liggen. Dit boek is daarmee bestemd voor toezichthouders, beleidsmakers en onderzoekers die willen weten hoe innovaties in het toezicht in de praktijk uitpakken

A Pulsed Gas Stripper for Stripping of High-Intensity, Heavy-Ion Beams at 1.4 MeV/u at the GSI UNILAC

The GSI UNILAC in combination with SIS18 will serve as a high-current, heavy-ion injector for the future FAIR. It has to meet high demands in terms of beam brilliance at a low duty factor (100 mus beam pulse length, 2.7 Hz repetition rate). An advanced 1.4 MeV/u gas stripper setup has been developed, aiming at an enhanced yield into the required charge states. The setup delivers short, high-density gas pulses in synchronization with the beam pulse. This provides an increased gas density at a reduced gas load for the differential pumping system. In recent measurements, high-intensity, heavy-ion beams of U⁴⁺ were successfully stripped and separated for the desired charge state. The modified stripper setup, as well as major results, are presented, including a comparison to the present gas stripper based on a N₂ gas-jet. The stripping efficiency into the desired 28⁺ charge state was significantly increased by up to 60 % using a hydrogen stripper target while the beam quality remained similar

Crystallographic structure of ultrathin Fe films on Cu(100)

We report bcc-like crystal structures in 2-4 ML Fe films grown on fcc Cu(100) using scanning tunneling microscopy. The local bcc structure provides a straightforward explanation for their frequently reported outstanding magnetic properties, i.e., ferromagnetic ordering in all layers with a Curie temperature above 300 K. The non-pseudomorphic structure, which becomes pseudomorphic above 4 ML film thickness is unexpected in terms of conventional rules of thin film growth and stresses the importance of finite thickness effects in ferromagnetic ultrathin films.Comment: 4 pages, 3 figures, RevTeX/LaTeX2.0

Diffuse-interface model for rapid phase transformations in nonequilibrium systems

A thermodynamic approach to rapid phase transformations within a diffuse interface in a binary system is developed. Assuming an extended set of independent thermodynamic variables formed by the union of the classic set of slow variables and the space of fast variables, we introduce finiteness of the heat and solute diffusive propagation at the finite speed of the interface advancing. To describe the transformation within the diffuse interface, we use the phase-field model which allows us to follow the steep but smooth change of phases within the width of diffuse interface. The governing equations of the phase-field model are derived for the hyperbolic model, model with memory, and for a model of nonlinear evolution of transformation within the diffuse-interface. The consistency of the model is proved by the condition of positive entropy production and by the outcomes of the fluctuation-dissipation theorem. A comparison with the existing sharp-interface and diffuse-interface versions of the model is given.Comment: 15 pages, regular article submitted to Physical Review

Diminished impact of ethnicity as a risk factor for chronic kidney disease in the current HIV treatment era

BACKGROUND: Chronic kidney disease (CKD) is an important comorbidity during human immunodeficiency virus (HIV) infection. Historically, HIV-associated nephropathy has been the predominant cause of CKD and has primarily been observed in people of African ancestry. This study aims to investigate the role of ethnicity in relation to CKD risk in recent years.METHODS: Analyses were performed including 16 836 patients from the Dutch AIDS Therapy Evaluation in the Netherlands (ATHENA) cohort. Baseline was defined as the first available creatinine level measurement after 1 January 2007; CKD was defined as a glomerular filtration rate of &lt;60 mL/min/1.73 m(2). The associations between ethnicity and both prevalent CKD at baseline and incident CKD during follow-up were analyzed.RESULTS:The prevalence of baseline CKD was 2.7% (460 of 16 836 patients). Birth in a sub-Saharan African country (hereafter, "SSA origin") was significantly associated with baseline CKD (adjusted odds ratio 1.49; 95% confidence interval [CI], 1.04-2.13). During follow-up (median duration, 4.7 years; interquartile range, 2.4-5.2), the rate of incident CKD was 6.0 events per 1000 person-years. The risk of newly developing CKD was similar between patients of SSA origin and those born in Western Europe, Australia, or New Zealand (adjusted hazard ratio, 1.00; 95% CI, .63-1.59).CONCLUSIONS: Among HIV-infected patients in the Netherlands, being of SSA origin was associated with a higher baseline CKD prevalence but had no impact on newly developing CKD over time. This suggests a shift in the etiology of CKD from HIV-associated nephropathy toward other etiologies.</p

Excited States of Ladder-type Poly-p-phenylene Oligomers

Ground state properties and excited states of ladder-type paraphenylene oligomers are calculated applying semiempirical methods for up to eleven phenylene rings. The results are in qualitative agreement with experimental data. A new scheme to interpret the excited states is developed which reveals the excitonic nature of the excited states. The electron-hole pair of the S1-state has a mean distance of approximately 4 Angstroem.Comment: 24 pages, 21 figure

The balloon-borne large-aperture submillimeter telescope for polarimetry: BLAST-Pol

The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLAST-Pol) is a suborbital mapping experiment designed to study the role played by magnetic fields in the star formation process. BLAST-Pol is the reconstructed BLAST telescope, with the addition of linear polarization capability. Using a 1.8 m Cassegrain telescope, BLAST-Pol images the sky onto a focal plane that consists of 280 bolometric detectors in three arrays, observing simultaneously at 250, 350, and 500 um. The diffraction-limited optical system provides a resolution of 30'' at 250 um. The polarimeter consists of photolithographic polarizing grids mounted in front of each bolometer/detector array. A rotating 4 K achromatic half-wave plate provides additional polarization modulation. With its unprecedented mapping speed and resolution, BLAST-Pol will produce three-color polarization maps for a large number of molecular clouds. The instrument provides a much needed bridge in spatial coverage between larger-scale, coarse resolution surveys and narrow field of view, and high resolution observations of substructure within molecular cloud cores. The first science flight will be from McMurdo Station, Antarctica in December 2010.Comment: 14 pages, 9 figures Submitted to SPIE Astronomical Telescopes and Instrumentation Conference 201