Meter-scale spark X-ray spectrumstatistics

X-ray emission by sparks implies bremsstrahlung from a population of energetic electrons, but the details of this process remain a mystery. We present detailed statistical analysis of X-ray spectra detected by multiple detectors during sparks produced by 1 MV negative high-voltage pulses with 1 $\mu$s risetime. With over 900 shots, we statistically analyze the signals, assuming that the distribution of spark X-ray fluence behaves as a power law and that the energy spectrum of X-rays detectable after traversing $\sim$2 m of air and a thin aluminum shield is exponential. We then determine the parameters of those distributions by fitting cumulative distribution functions to the observations. The fit results match the observations very well if the mean of the exponential X-ray energy distribution is 86 $\pm$ 7 keV and the spark X-ray fluence power law distribution has index -1.29 $\pm$ 0.04 and spans at least 3 orders of magnitude in fluence

A microfluidic-FCS platform for investigation on the dissociation of Sp1-DNA complex by doxorubicin

The transcription factor (TF) Sp1 is a well-known RNA polymerase II transcription activator that binds to GC-rich recognition sites in a number of essential cellular and viral promoters. In addition, direct interference of Sp1 binding to DNA cognate sites using DNA-interacting compounds may provide promising therapies for suppression of cancer progression and viral replication. In this study, we present a rapid, sensitive and cost-effective evaluation of a GC intercalative drug, doxorubicin (DOX), in dissociating the Sp1–DNA complex using fluorescence correlation spectroscopy (FCS) in a microfluidic system. FCS allows assay miniaturization without compromising sensitivity, making it an ideal analytical method for integration of binding assays into high-throughput, microfluidic platforms. A polydimethylsiloxane (PDMS)-based microfluidic chip with a mixing network is used to achieve specific drug concentrations for drug titration experiments. Using FCS measurements, the IC(50) of DOX on the dissociation of Sp1–DNA complex is estimated to be 0.55 μM, which is comparable to that measured by the electrophoretic mobility shift assay (EMSA). However, completion of one drug titration experiment on the proposed microfluidic-FCS platform is accomplished using only picograms of protein and DNA samples and less than 1 h total assay time, demonstrating vast improvements over traditional ensemble techniques

Fluorescence correlation spectroscopy of the binding of nucleotide excision repair protein XPC-hHr23B with DNA substrates

The interaction of the nucleotide excision repair (NER) protein dimeric complex XPC-hHR23B, which is implicated in the DNA damage recognition step, with three Cy3.5 labeled 90-bp double-stranded DNA substrates (unmodified, with a central unpaired region, and cholesterol modified) and a 90-mer single-strand DNA was investigated in solution by fluorescence correlation spectroscopy. Autocorrelation functions obtained in the presence of an excess of protein show larger diffusion times (τ d) than for free DNA, indicating the presence of DNA-protein bound complexes. The fraction of DNA bound (θ), as a way to describe the percentage of protein bound to DNA, was directly estimated from FCS data. A significantly stronger binding capability for the cholesterol modified substrate (78% DNA bound) than for other double-stranded DNA substrates was observed, while the lowest affinity was found for the single-stranded DNA (27%). This is in accordance with a damage recognition role of the XPC protein. The similar affinity of XPC for undamaged and 'bubble' DNA sub

Transcribing, Coding and Eating Our Way Through a Renaissance French Cookbook

The process of creating a digital scholarly edition of a Renaissance French cookbook, Le Livre de cuysine [The Book of Cookery], provided a unique opportunity to study the history of 16th century cuisine. This project required learning how to read a Gothic printed text and understanding the recipes contained in a cookbook from this period. The final project involved transcribing and then coding the text in XML using TEI mark-up language. Along the way, we had to make editorial decisions that arose because of the nature of the cookbook text. For example, TEI coding requires that paragraphs be distinguished in the text and coding. This posed a challenge because the cookbook did not have clearly divided paragraphs. The archaic spelling in the original text also raised questions about whether or not to modernize the spelling. Finally, since this cookbook edition was filled with printing mistakes, we occasionally had to insert notes to explain difficult passages. In the end, the completed digitized text now allows new access to scholars to learn more about the text and Renaissance French cuisine. Instead of participating in a traditional lecture course on French literature, we were able to obtain hands-on experience doing actual scholarly research. The experiential nature of the course then culminated in a Renaissance French banquet complete with dishes made from recipes out of Le Livre de cuysine

Perceived fitness predicts daily coping better than physical activity

One hundred sixty-six participants (70 males, 96 females) completed a series of questionnaires measuring perceived fitness, social desirability, self-esteem, hope, and perceived stress levels and coping abilities. Participants were then given an activity monitoring device to wear for 1 week. Participants recorded daily measures of physical activity, perceived fitness, and perceived stress and coping over 7 days. Results revealed that although perceived physical fitness was reliably associated with coping, actual physical activity was not. These associations remained even after statistically controlling for gender, social desirability, self-esteem, hope, perceived stress, and anxiety. Findings suggest that perceived physical fitness may be a better predictor of daily coping than actual physical activity

Analysis of Russian thistle (Salsola species) selections for factors affecting forage nutritional value

The need for forage plants that are productive in, and adapted to, semiarid conditions prompted us to examine the range and independence of assortment of nutritional qualities of wild stands of Russian thistle (Salsola species). Seventy selections from a 5-state area of the southwestern United States were planted in observational plots and analyzed for crude protein, acid detergent fiber, lignin, nitrate, water-soluble oxalate, in vitro digestibility, and ash content at 2 stages of maturity. Values on a dry matter basis of crude protein (5.4 to 22.3%), acid detergent fiber (20.1 to 48.8%), acid detergent lignin (3.1 to 10.4%), nitrate (0.1 to 5.1%), water-soluble oxalate (0.2 to 9.1%), plant height (40 to 180 cm at second harvest), stage of development (midbloom to complete seed development at second harvest), and degree of prickliness (soft to extremely prickly at second harvest) were determined for each of the 70 selections at 2 harvest times. The color, branch density, and degree of leafiness were examined at the second harvest only. Values for in vitro digestibility (45.1 to 66.3% organic matter disappearance) and ash (12.7 to 30.5% of dry wt) were determined for a subset of 22 samples. About 10% of the selections had a composite of properties which would suggest they they would make moderate to good forages.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202