Fractionation of human immune γ-globulin

Equine and bovine serum proteins have recently been fractionated by means of a physical method utilizing an electrophoretic adaptation of the principles of the Clusius column (l-4), first described and tested by Kirkwood (5) and Nielsen (6). The method of electrophoresis-convection has now been applied to the fractionation of human γ-globulin. The γ-globulin was prepared by ethanol fractionation (7) from the plasma of individuals hyperimmunized to Hemophilus pertussis organisms. The resulting fractions of γ-globulin have been characterized electrophoretically, and the protective antibody activity and agglutinin titer have been measured

Influence of dielectric thickness and electrode structure on the ion wind generation by micro fabricated plasma actuators

Surface dielectric barrier discharges are investigated in order to explore the combined effects of barrier thickness and microstructure of the exposed electrode on the ion wind generation. Actuators with straight and structured high voltage electrodes with characteristic sizes of 200 and 250 µm and dielectric thicknesses of 0.5, 1 and 2 mm are compared. It is observed that: i) actuator efficiency of ion wind generation strongly depends on the applied voltage amplitude; ii) operation voltage depends on the dielectric thickness logarithmically; iii) electrode microstructure slightly increases the dynamic pressure (few percent in maximum), however the effect decreases with thicker dielectrics and smaller electrode structures; iv) the pattern of the most intensive discharge parts as well as the dielectric erosion repeats the regular structure of the electrodes down to 200 µm. Several identical samples are tested during different days to estimate the impact of the air humidity and the degradation of the dielectric. The microscale precision of the sample manufacture was accomplished by a commercial facility for printed circuit boards. © 2020 The Author(s). Published by IOP Publishing Ltd

APT cooling water supply make-up trade study. Revision 1

In the conceptual design of the APT cooling water system, several options exist for the design of the system(s) which serve as the ultimate heat sink. This study will evaluate alternative methods of providing an ultimate heat sink to the APT

APT cooling water supply make-up trade study. Revision 1

In the conceptual design of the APT cooling water system, several options exist for the design of the system(s) which serve as the ultimate heat sink. This study will evaluate alternative methods of providing an ultimate heat sink to the APT

An evaluation of food as a potential source for clostridium difficile acquisition in hospitalized patients

OBJECTIVETo determine whetherClostridium difficileis present in the food of hospitalized patients and to estimate the risk of subsequent colonization associated withC. difficilein food.METHODSThis was a prospective cohort study of inpatients at a university-affiliated tertiary care center, May 9, 2011–July 12, 2012. Enrolled patients submitted a portion of food from each meal. Patient stool specimens and/or rectal swabs were collected at enrollment, every 3 days thereafter, and at discharge, and were cultured forC. difficile. Clinical data were reviewed for evidence of infection due toC. difficile.A stochastic, discrete event model was developed to predict exposure toC. difficilefrom food, and the estimated number of new colonization events from food exposures per 1,000 admissions was determined.RESULTSA total of 149 patients were enrolled and 910 food specimens were obtained. Two food specimens from 2 patients were positive forC. difficile(0.2% of food samples; 1.3% of patients). Neither of the 2 patients was colonized at baseline withC. difficile. Discharge colonization status was available for 1 of the 2 patients and was negative. Neither was diagnosed withC. difficileinfection while hospitalized or during the year before or after study enrollment. Stochastic modeling indicated contaminated hospital food would be responsible for less than 1 newly colonized patient per 1,000 hospital admissions.CONCLUSIONSThe recovery ofC. difficilefrom the food of hospitalized patients was rare. Modeling suggests hospital food is unlikely to be a source ofC. difficileacquisition.Infect Control Hosp Epidemiol2016;1401–1407</jats:sec

The Phosphorus/Sulfur Abundance Ratio as a Test of Galactic Cosmic-Ray Source Models

Galactic cosmic-ray (GCR) elemental abundances display a fractionation compared to solar-system values that appears ordered by atomic properties such as the first ionization potential (FIP) or condensation temperature (volatility). Determining which parameter controls the observed fractionation is crucial to distinguish between GCR origin models. The Cosmic-Ray Isotope Spectrometer (CRIS) instrument on board NASA's Advanced Composition Explorer (ACE) spacecraft can measure the abundances of several elements that break the general correlation between FIP and volatility (e.g., Na, P, K, Cu, Zn, Ga, and Ge). Phosphorus is a particularly interesting case as it is a refractory (high condensation temperature) element with a FIP value nearly identical to that of its semi-volatile neighbor, sulfur. Using a leaky-box galactic propagation model we find that the P/S and Na/Mg ratios in the GCR source favor volatility as the controlling parameter

On the Low Energy Decrease in Galactic Cosmic Ray Secondary/Primary Ratios

Galactic cosmic ray (GCR) secondary/primary ratios such as B/C and (Sc+Ti+V)/Fe are commonly used to determine the mean amount of interstellar material through which cosmic rays travel before escaping from the Galaxy (Λ_(esc)). These ratios are observed to be energy-dependent, with a relative maximum at ~1 GeV/nucleon, implying a corresponding peak in Λ_(esc). The decrease in Λ_(esc) at energies above 1 GeV/nucleon is commonly taken to indicate that higher energy cosmic rays escape more easily from the Galaxy. The decrease in Λ_(esc) at energies <1 GeV/nuc is more controversial; suggested possibilities include the effects of a galactic wind or the effects of distributed acceleration of cosmic rays as they pass through the interstellar medium. We consider two possible explanations for the low energy decrease in Λ_(esc) and attempt to fit the combined, high-resolution measurements of secondary/primary ratios from ~0.1 to 35 GeV/nuc made with the CRIS instrument on ACE and the C2 experiment on HEAO-3. The first possibility, which hypothesizes an additional, local component of low-energy cosmic rays that has passed through very little material, is found to have difficulty simultaneously accounting for the abundance of both B and the Fe-secondaries. The second possibility, suggested by Soutoul and Ptuskin, involves a new form for Λ_(esc) motivated by their diffusion-convection model of cosmic rays in the Galaxy. Their suggested form for Λ_(esc)(E) is found to provide an excellent fit to the combined ACE and HEAO data sets

Frequency of instrument, environment, and laboratory technologist contamination during routine diagnostic testing of infectious specimens

ABSTRACT Laboratory testing to support the care of patients with highly infectious diseases may pose a risk for laboratory workers. However, data on the risk of virus transmission during routine laboratory testing conducted using standard personal protective equipment (PPE) are sparse. Our objective was to measure laboratory contamination during routine analysis of patient specimens. Remnant specimens were spiked with the nonpathogenic bacteriophage MS2 at 1.0 × 10 7 PFU/ml, and contamination was assessed using reverse transcriptase PCR (RT-PCR) for MS2. Specimen containers were exteriorly coated with a fluorescent powder to enable the visualization of gross contamination using UV light. Testing was performed by two experienced laboratory technologists using standard laboratory PPE and sample-to-answer instrumentation. Fluorescence was noted on the gloves, bare hands, and laboratory coat cuffs of the laboratory technologist in 36/36 (100%), 13/36 (36%), and 4/36 (11%) tests performed, respectively. Fluorescence was observed in the biosafety cabinet (BSC) in 8/36 (22%) tests, on test cartridges/devices in 14/32 (44%) tests, and on testing accessory items in 29/32 (91%) tests. Fluorescence was not observed on or in laboratory instrumentation or adjacent surfaces. In contrast to fluorescence detection, MS2 detection was infrequent (3/286 instances [1%]) and occurred during test setup for the FilmArray instrument and on FilmArray accessory equipment. The information from this study may provide opportunities for the improvement of clinical laboratory safety practices so as to reduce the risk of pathogen transmission to laboratory workers. </jats:p