Backbone and side chain H-1, N-15 and C-13 assignments for the oxidised and reduced forms of the oxidoreductase protein DsbA from Staphylococcus aureus

The function and dynamics of the thiol-disulfide oxidoreductase DsbA in the low-GC gram positive bacterium, Staphylococcus aureus, are yet to be elucidated. Here we report 13C, 15N and 1H assignments for the oxidised and reduced forms of SaDsbA as a prelude to further studies on the enzyme

Improving the Weizs\"acker-Williams Approximation in Electron-Proton Collisions

We critically examine the validity of the Weizs\"acker-Williams approximation in electron-hadron collisions. We show that in its commonly used form it can lead to large errors, and we show how to improve it in order to get accurate results. In particular, we present an improved form that is valid beyond the leading logarithmic approximation in the case when a small-angle cut is applied to the scattered electron. Furthermore we include comparisons of the approximate expressions with the exact electroproduction calculation in the case of heavy-quark production.Comment: 10 pages (LaTex, style file included) + 3 table

Influence of Planting Date and Weed Interference on Sweet Corn Growth and Development

Crop planting date and canopy density influence interactions between weeds and sweet corn (Zea mays L.); however, little is known about sweet corn growth response to weed interference. Field studies were conducted in 2004 and 2005 near Urbana, IL, to quantify the influence of planting date and weed interference on growth of sweet corn height, leaf area, aboveground biomass, and phenological development. Crop growth response to weed interference (presence or absence) was determined for sweet corn planted early May (EARLY) and late June (LATE). Dominant weed species included barnyardgrass [Echinochloa crus-galli (L.) Beauv.], common lambsquarters (Chenopodium album L.), common purslane (Portulaca oleracea L.), green foxtail [Setaria viridus (L.) Beauv.], redroot pigweed (Amaranthus retroflexus L.), and velvetleaf (Abutilon theophrasti Medicus) at densities ranging from 95 to 256 plants m-2. Weed interference reduced sweet corn’s absolute height growth rate, maximum leaf area index (LAI), absolute LAI growth rate, with some of the largest effects on crop growth observed in the EARLY planting date. Silk emergence was delayed by weeds for EARLY planted sweet corn, but not LATE. Moreover, the LATE planting date resulted in 9% taller crop plants with 36% lower maximum LAI. Relative to an EARLY planting date, lower yield losses due to weeds for LATE sweet corn correspond to greater resiliency of crop growth and silk emergence to weed interference

A Smarter Way to Make Early and Mid-Career Decisions

Libraries set themselves apart as safe spaces for people of all ages to learn, explore, and share new ideas. That being said, how comfortable are you talking to your colleagues about making a career move? Do you have reliable information to help you make decisions

Scanning Tunneling Microscopy and Spectroscopy on Iron-Pnictides

Tremendous excitement has followed the recent discovery of superconductivity up to Tc= 56 K in iron–arsenic based materials (pnictides). This discovery breaks the monopoly on high-Tc superconductivity held by copper-oxides (cuprates) for over two decades and renews hope that high-Tc superconductivity may finally be theoretically understood and widely applied. Since scanning tunneling microscopy (STM) and spectroscopy (STS) have been key tools in the investigation and understanding of both conventional and unconventional superconductivity, these techniques are also applied to the pnictides. While the field is still in its early stages, several important achievements by STM and STS have been reported on the pnictides. In this paper, we will review their contribution towards an understanding of superconductivity in this new class of materials.Physic

A single amino acid substitution in ORF1 dramatically decreases L1 retrotransposition and provides insight into nucleic acid chaperone activity

L1 is a ubiquitous interspersed repeated sequence in mammals that achieved its high copy number by autonomous retrotransposition. Individual L1 elements within a genome differ in sequence and retrotransposition activity. Retrotransposition requires two L1-encoded proteins, ORF1p and ORF2p. Chimeric elements were used to map a 15-fold difference in retrotransposition efficiency between two L1 variants from the mouse genome, TFC and TFspa, to a single amino acid substitution in ORF1p, D159H. The steady-state levels of L1 RNA and protein do not differ significantly between these two elements, yet new insertions are detected earlier and at higher frequency in TFC, indicating that it converts expressed L1 intermediates more effectively into new insertions. The two ORF1 proteins were purified and their nucleic acid binding and chaperone activities were examined in vitro. Although the RNA and DNA oligonucleotide binding affinities of these two ORF1 proteins were largely indistinguishable, D159 was significantly more effective as a nucleic acid chaperone than H159. These findings support a requirement for ORF1p nucleic acid chaperone activity at a late step during L1 retrotransposition, extend the region of ORF1p that is known to be critical for its functional interactions with nucleic acids, and enhance understanding of nucleic acid chaperone activity

Geometrically induced modification of surface plasmons in the optical and telecom regimes

We demonstrate that the introduction of a subwavelength periodic modulation into a metallic structure strongly modifies the guiding characteristics of the surface plasmon modes supported by the system. Moreover, it is also shown how a new type of a tightly confined surface plasmon polariton mode can be created by just milling a periodic corrugation into a metallic ridge placed on top of a metal surface

Dynamic Stability and Control Problems of Piloted Reentry from Lunar Missions

A fixed-base simulator investigation has been made of stability and control problems during piloted reentry from lunar missions. Reentries were made within constraints of acceleration and skipping, in which the pilot was given simulated navigation tasks of altitude and heading angle commands. Vehicles considered included a blunt-face, high-drag capsule, and a low-drag lifting cone, each of which had a trim lift-drag ratio of 0.5. With the provision of three-axis automatic damping, both vehicles were easily controlled through reentry after a brief pilot-training period. With all dampers out, safe reentries could be made and both vehicles were rated satisfactory for emergency operation. In damper-failure conditions resulting in inadequate Dutch roll damping, the lifting-cone vehicle exhibited control problems due to excessive dihedral effect and oscillatory acceleration effects

Identifying flies used for maggot debridement therapy

To the Editor: The use of maggots to clean necrotic wounds, known as maggot debridement therapy (MDT), has long been known to the scientific world. Its use has been recorded since the 1500s when soldiers’ wounds were often infested with maggots. Napoleon’s surgeon, Baron Dominic Larrey, reported that wounds that were infested with maggots appeared to heal faster than those without maggots.1 William Baer is considered to be the founder of modern MDT. While treating soldiers in World War I, he noted the good condition of wounds that had been infested with maggots, and was the first doctor on record to experiment with the use of maggots in treating infections.1 MDT even featured in the recent version of the film ‘Spartacus’. Various species of flies have been used for MDT,1 the most commonly used being Lucilia sericata, a greenbottle blowfly (Figs 1 and 2). This fly is closely related to another greenbottle, L. cuprina, but L. cuprina feeds on live as well as necrotic tissue, which is undesirable in MDT. L. cuprina is commonly named the ‘sheep blowfly’ because it is responsible for fly-strike in sheep, a form of massive, usually rectal myiasis that can kill sheep. A recent article2 suggested that L. cuprina was being used successfully for MDT at the Eugene Marais Hospital Wound Care Centre (EMHWCC). As this would be inconsistent with international experience in MDT and at odds with the usual biology of L. cuprina, it was decided to check the identity of these flies