Modeling the propagation of a high-average-power train of ultrashort laser pulses

We investigate the interpulse thermal interaction of a train of ultrashort laser pulses and develop a model to describe the isobaric heating of air by a train of pulses undergoing filamentation. We calculate the heating of air from a single laser pulse and the resulting refractive index perturbation encountered by subsequent pulses, and use this to simulate the propagation of a high-power pulse train. The simulations show deflection of laser filaments by the thermal refractive index consistent with previous experimental measurements.

Progress curve analysis of microtitre plate plasma clotting assays. Assessment of tissue factor levels

MTP plasma clotting assays monitor the time course of fibrin formation in re-calcified plasma by absorbance measurements and are increasingly used as alternatives to traditional one-point clot time assays employed in clinical laboratories to detect thrombotic disorders. The parameters derived from these analyses are analogous to thromboelastography viz. time, rate and maximum extent of clot formation. The derived parameters, based on the whole course of the clotting reaction are more robust, informative and quantitative than single-point clot time assays. However, the parameters themselves are usually obtained arbitrarily by crude graphical analysis of subjectively selected points of progress curves. The current work aimed to investigate the sensitivity and reproducibility of an MTP clotting assay and examine its suitability for measuring tissue factor (TF) levels in cell culture medium and patient urine. The results demonstrate that progress curves can be analysed by fitting a logistic equation, derived from a simplified autocatalytic clot formation model. The parameters, maximum amplitude (Fm), rate constant (k), time to half-maximum amplitude (tm) and maximum rate of clot formation (vm), fit a power curve showing limiting effects with increasing TF concentration. Log/log plots of tm and k against TF concentration provide standard curves for assessment of unknowns.

Benchmarking background oriented schlieren against interferometric measurement using open source tools

Gas flow from an under-expanding jet nozzle is measured using synchronized background oriented schlieren and interferometry diagnostics. The gas density distribution is obtained from a shift vector field of the background oriented schlieren and compared to the interferometric data. The comparison makes use of a simple calibration routine and open source Python recipes.

Progress Curve Analysis of the one stage chromogenic assay for ecarin

Snake venom prothrombin activators such as Ecarin are readily assayed by continuous spectrophotometric monitoring of p-nitroaniline production in a one step assay containing prothrombin and a p-nitroanilide peptide substrate for thrombin. The coupled reactions result in accelerating p-nitroaniline (pNA) production over the course of the assay giving non-linear progress curves, from which initial velocities are not readily obtained. Most studies therefore resort to approximate estimates of activity, based on the absorbance reached at an arbitrary time. A simple kinetic analysis of the coupled reactions shows that the early points of such curves should be fitted by second order polynomials, representing the accelerating reaction rate in μmol pNA/min/min. The first derivative of the polynomial then gives the increasing velocity of pNA production in μmol pNA/min over the time course of the assay. We demonstrate here that, with the substrate S2238, these rates can be converted to absolute thrombin concentrations using the Michaelis-Menten equation, substituted with values for kcat and Km. These thrombin concentrations increase linearly over the time course of the assay allowing the activity to be expressed in units, defined as μmol product/min, most commonly used to report enzyme activity.

Evaluation of the VIDAS Staph Enterotoxin II (SET 2) Immunoassay Method for the Detection of Staphylococcal Enterotoxins in Selected Foods: Collaborative Study

A multilaboratory study was conducted to determine the limit of detection (LOD) of Staphylococcal enterotoxins (SET) in 5 foods. Cooked chicken, ham, potato salad, pasteurized liquid whole milk, and canned mushrooms were each spiked with a different enterotoxin (A, B, C1, D, or E), and tested at 0.25 and 0.5 ng/g SET levels to determine the LOD of the assay for those foods in a collaborative study. Unspiked controls were also included. A total of 19 laboratories representing government and industry participated. In this study, 1674 test portions were analyzed, of which 1638 were used in the statistical analysis. Of the 1638 test portions used in the statistical analysis, 1104 were spiked test portions, of which 1073 were positive by the VIDAS Staph enterotoxin II (SET 2) method. The detection rates at the 0.25 ng/mL level were cooked chicken, 98.2; ham, 99.0; potato salad, 99.1; liquid whole milk, 85.2; and canned mushrooms, 100. The detection rates at the 0.5 ng/mL level were cooked chicken, 97.4; ham, 98.1; potato salad, 100; liquid whole milk, 99.0; and canned mushrooms, 100. The data indicate that the SET 2 method is capable of detecting SET at 0.25 ng/g in cooked chicken, ham, potato salad, and canned mushrooms and at 0.5 ng/g in pasteurized liquid whole milk.

Rapid serum tube technology overcomes problems associated with use of anticoagulants

Introduction

Failure to obtain complete blood clotting in serum is a common laboratory problem. Our aim was to determine whether snake proth-rombin activators are effective in clotting blood and producing quality serum for analyte measurement in anticoagulated patients.

Materials and methods

Whole blood clotting was studied in a total of 64 blood samples (41 controls, 20 Warfarin patients, 3 anticoagulated patients using snake venom prothrombin activator (OsPA)) with plain tubes. Coagulation was analysed using a visual assay, Hyland-Clotek and thromboelastography. Healthy control blood was spiked with a range of anticoagulants to determine the effectiveness of OsPa-induced clotting. A paired analysis of a Dabigatran patient and a control investigated the effectiveness of the OsPA clotting tubes. Biochemical analytes (N = 31) were determined for 7 samples on chemistry and immunoassay analysers and compared with commercial tubes.

Results

Snake venom prothrombin activators efficiently coagulated blood and plasma spiked with heparin and commonly used anticoagulants. Clotting was observed in the presence of anticoagulants whereas no clotting was observed in BDRST tubes containing 3 U/mL of heparin. Snake venom prothrombin activator enhanced heparinised blood clotting by shortening substantially the clotting time and improving significantly the strength of the clot. Comparison of 31 analytes from the blood of five healthy and two anticoagulated participants gave very good agreement between the analyte concentrations determined.

Conclusions

Our results showed that the snake venom prothrombin activators OsPA and PtPA efficiently coagulated recalcified and fresh bloods with or without added anticoagulants. These procoagulants produced high quality serum for accurate analyte measurement.

Lensing properties of rotational gas flow: erratum

This erratum includes additional references relevant to rotational gas flow negative lenses that were omitted in Appl. Opt.57, 9392 (2018)APOPAI0003-693510.1364/AO.57.009392.

Lensing properties of rotational gas flow

A negative lens comprising a gas in steady axisymmetric flow is demonstrated experimentally and analyzed. The lens has potential applications in high-intensity laser optics and presents the possibility of adjusting the focusing properties on a submillisecond time scale. It can be operated in environments where conventional optical elements are vulnerable.

Next-generation rapid serum tube technology using prothrombin activator coagulant: fast, high-quality serum from normal samples

Background

Incomplete blood clotting or latent clotting in serum is a common laboratory problem, especially for patients on anticoagulant therapy or when serum tubes are centrifuged before clotting is completed. We describe a novel approach to producing high-quality serum using snake venom prothrombin activator complex (OsPA) as an additive in blood collection tubes for non-anticoagulated (normal) individuals.

Methods

Plasma clotting assays were performed using a Hyland-Clotek instrument. Blood clotting was visually observed, and thromboelastography was also performed to determine the important parameters of coagulation. Thrombin generation was assayed using the chromogenic substrate S-2238, and biochemical analytes in the serum were determined on chemistry and immunoassay analysers. Fibrinogen was determined by either ELISA or Clauss fibrinogen assay.

Results

We initially showed that OsPA had strong coagulation activity in clotting not only recalcified citrated plasma and recalcified citrated whole blood, but also fresh whole blood in a clinical setting. The use of TEG clearly showed improved speed of clotting and generation of a firmer clot. We also showed that the use of OsPA to produce serum did not interfere with the determination of commonly measured biochemical analytes. The underlying clotting mechanism involves a burst of thrombin production at the initial stages of the clotting process upon contact with prothrombin in blood.

Conclusions

These results demonstrate rapid generation of high-quality serum, contributing to faster turnaround times with standardised quality samples, for accurate analyte determinations in normal individuals.

Impact of scientific and technological advances

Advancements in research and technology are transforming our world. The dental profession is changing too, in the light of scientific discoveries that are advancing biological technology-from new biomaterials to unravelling the genetic make-up of the human being. As health professionals, we embrace a model of continuous quality improvement and lifelong learning. Our pedagogical approach to incorporating the plethora of scientific-technological advancements calls for us to shift our paradigm from emphasis on skill acquisition to knowledge application. The 2017 ADEE/ADEA workshop provided a forum to explore and discuss strategies to ensure faculty, students and, ultimately, patients are best positioned to exploit the opportunities that arise from integrating new technological advances and research outcomes. Participants discussed methods of incorporating the impact of new technologies and research findings into the education of our dental students. This report serves as a signpost of the way forward and how to promote incorporation of research and technology advances and lifelong learning into the dental education curriculum.

Reciprocity breaking during nonlinear propagation of adapted beams through random media

Adaptive optics (AO) systems rely on the principle of reciprocity, or symmetry with respect to the interchange of point sources and receivers. These systems use the light received from a low power emitter on or near a target to compensate phase aberrations acquired by a laser beam during linear propagation through random media. If, however, the laser beam propagates nonlinearly, reciprocity is broken, potentially undermining AO correction. Here we examine the consequences of this breakdown, providing the first analysis of AO applied to high peak power laser beams. While discussed for general random and nonlinear media, we consider specific examples of Kerr-nonlinear, turbulent atmosphere.

Sex-Sorted Boar Sperm - An Update on Related Production Methods

As in other mammals, sex sorting of pig sperm is based on quantitative flow cytometry. A major disadvantage of the technique is the relatively low efficiency to produce enough sorted sperm for artificial insemination. However, several approaches are on the way to make sexed pig sperm available for commercial application. In this context, for example, the growing field of nanotechnology may significantly contribute to these developments, as it provides highly efficient bio-nanoprobes, for example, based on plasmonic nanoparticles. Independent of the method, further development requires enormous investments and set-up of logistics to get the technology into the practical pig market. Only global players will be able to establish the necessary research projects, but in the end, a significant shift of sex ratios will be available for pig producers as it is already the case for the dairy industry.

The effects of frozen tissue storage conditions on the integrity of RNA and protein

Unfixed tissue specimens most frequently are stored for long term research uses at either -80° C or in vapor phase liquid nitrogen (VPLN). There is little information concerning the effects such long term storage on tissue RNA or protein available for extraction. Aliquots of 49 specimens were stored for 5-12 years at -80° C or in VPLN. Twelve additional paired specimens were stored for 1 year under identical conditions. RNA was isolated from all tissues and assessed for RNA yield, total RNA integrity and mRNA integrity. Protein stability was analyzed by surface-enhanced or matrix-assisted laser desorption ionization time of flight mass spectrometry (SELDI-TOF-MS, MALDI-TOF-MS) and nano-liquid chromatography electrospray ionization tandem mass spectrometry (nLC-ESI-MS/MS). RNA yield and total RNA integrity showed significantly better results for -80° C storage compared to VPLN storage; the transcripts that were preferentially degraded during VPLN storage were these involved in antigen presentation and processing. No consistent differences were found in the SELDI-TOF-MS, MALDI-TOF-MS or nLC-ESI-MS/MS analyses of specimens stored for more than 8 years at -80° C compared to those stored in VPLN. Long term storage of human research tissues at -80° C provides at least the same quality of RNA and protein as storage in VPLN.

Laboratory medicine best practice guideline: vitamins a, e and the carotenoids in blood

Despite apparent method similarities between laboratories there appear to be confounding factors inhibiting uniform reporting and standardisation of vitamin assays. The Australasian Association of Clinical Biochemists (AACB) Vitamins Working Party, in conjunction with The Royal College of Pathologists of Australasia Quality Assurance Programs, has formulated a guideline to improve performance, reproducibility and accuracy of fat-soluble vitamin results. The aim of the guideline is to identify critical pre-analytical, analytical and post-analytical components of the analysis of vitamins A, E and carotenoids in blood to promote best practice and harmonisation. This best practice guideline has been developed with reference to the Centers for Disease Control and Prevention (CDC) "Laboratory Medicine Best Practices: Developing an Evidence-Based Review and Evaluation Process". The CDC document cites an evaluation framework for generating best practice recommendations that are specific to laboratory medicine. These 50 recommendations proposed herein, were generated from a comprehensive literature search and the extensive combined experience of the AACB Vitamins Working Party members. They were formulated based on comparison between an impact assessment rating and strength of evidence and were classified as either: (1) strongly recommend, (2) recommend, (3) no recommendation for or against, or (4) recommend against. These best practice recommendations represent the consensus views, in association with peer reviewed evidence of the AACB Vitamins Working Party, towards best practice for the collection, analysis and interpretation of vitamins A, E and carotenoids in blood.

BMI but not stage or etiology of nonalcoholic liver disease affects the diagnostic utility of carbohydrate-deficient transferrin

BACKGROUND

A reliable biomarker is required in hepatology clinics for detection and follow-up of heavy alcohol consumption. Carbohydrate-deficient transferrin (CDT) increases with sustained heavy alcohol consumption and is the most specific biomarker of ethanol (EtOH) consumption. Recent introduction of a standardized method for measuring CDT has improved its clinical application. This study was designed to determine whether alcohol-independent factors influence CDT levels in patients with chronic liver disease (CLD).

METHODS

The relationship between serum %CDT and self-reported history of alcohol consumption was examined in 254 patients referred for evaluation of liver disease. CDT analysis was performed on serum collected at time of liver biopsy.

RESULTS

CDT levels were not affected by severity or etiology of nonalcoholic liver disease. Thirteen of 254 subjects had a %CDT >1.7, predictive of heavy alcohol intake, 6 of whom did not acknowledge heavy drinking. Twelve of these 13 subjects were suspected heavy drinkers on review of their medical records and clinical results. Conversely, not all acknowledged heavy drinkers had %CDT >1.7. Heavy drinkers with a body mass index (BMI) in the overweight or obese range had significantly lower %CDT than lean heavy drinkers. This persisted even when lean body weight was used as an approximation of the EtOH volume of distribution.

CONCLUSIONS

An elevated BMI reduces the diagnostic utility of CDT at higher alcohol intake in subjects with CLD using the standardized method. In a hepatology outpatient setting, this assay is likely to be useful to confirm suspicion of heavy drinking in subjects who are not overweight, but cannot reliably identify moderate drinkers or heavy drinkers who are overweight.

Direct electrical stimulation of the somatosensory cortex in humans using electrocorticography electrodes: a qualitative and quantitative report

OBJECTIVE

Recently, electrocorticography-based brain-computer interfaces have been successfully used to translate cortical activity into control signals for external devices. However, the utility of such devices would be greatly enhanced by somatosensory feedback. Direct stimulation of somatosensory cortex evokes sensory perceptions, and is thus a promising option for closing the loop. Before this can be implemented in humans it is necessary to evaluate how changes in stimulus parameters are perceived and the extent to which they can be discriminated.

APPROACH

Electrical stimulation was delivered to the somatosensory cortex of human subjects implanted with electrocorticography grids. Subjects were asked to discriminate between stimuli of different frequency and amplitude as well as to report the qualitative sensations elicited by the stimulation.

MAIN RESULTS

In this study we show that in humans implanted with electrocorticography grids, variations in the amplitude or frequency of cortical electrical stimulation produce graded variations in percepts. Subjects were able to reliably distinguish between different stimuli.

SIGNIFICANCE

These results indicate that direct cortical stimulation is a feasible option for sensory feedback with brain-computer interface devices.

The structure of human microplasmin in complex with textilinin-1, an aprotinin-like inhibitor from the Australian brown snake

Textilinin-1 is a Kunitz-type serine protease inhibitor from Australian brown snake venom. Its ability to potently and specifically inhibit human plasmin (K_i = 0.44 nM) makes it a potential therapeutic drug as a systemic anti-bleeding agent. The crystal structures of the human microplasmin-textilinin-1 and the trypsin-textilinin-1 complexes have been determined to 2.78 Å and 1.64 Å resolution respectively, and show that textilinin-1 binds to trypsin in a canonical mode but to microplasmin in an atypical mode with the catalytic histidine of microplasmin rotated out of the active site. The space vacated by the histidine side-chain in this complex is partially occupied by a water molecule. In the structure of microplasminogen the χ₁ dihedral angle of the side-chain of the catalytic histidine is rotated by 67° from its “active” position in the catalytic triad, as exemplified by its location when microplasmin is bound to streptokinase. However, when textilinin-1 binds to microplasmin the χ₁ dihedral angle of this amino acid residue changes by −157° (i.e. in the opposite rotation direction compared to microplasminogen). The unusual mode of interaction between textilinin-1 and plasmin explains textilinin-1′s selectivity for human plasmin over plasma kallikrein. This difference can be exploited in future drug design efforts.

Fluorometric evaluation of cryopreserved bovine spermatozoa extended in egg yolk and milk

A comparison of fluorogenically quantifiable parameters of cryopreserved, bovine spermatozoa that had been processed in homogenized milk and egg yolk citrate-based extenders was made using flow cytometry. Semen from four bulls was processed in egg yolk-citrate or homogenized milk extenders, packaged in straws and frozen at -196 degrees C. Samples were thawed at 37 degrees C, subdivided into three portions and stained after 0, 1.5 and 3 h of incubation at 37 degrees C. Spermatozoa were stained using a combination of carboxyfluorescein diacetate (CFDA) and propidium iodide (PI) and analyzed by dual parameter flow cytometry. The sperm cells were quantified fluorometrically at each time interval for both green and red fluorescence. The proportion of spermatozoa retaining the fluorescent CFDA derivative was larger at each time interval for samples in egg yolk citrate than those in milk. Differences in the retention of spermatozoal viability were detected between identical samples of bovine spermatozoa extended in milk or egg yolk based media.

International Conference on Boar Semen Preservation (ICBSP): the first 25 years

The International Conference on Boar Semen Preservation (ICBSP) has been in existence for 25 years. During that time, six conferences have been held in Europe and North America. Each conference has sought to communicate research advances in pig semen technology and artificial insemination (AI). Clearly, the conference has been a catalyst for the advancement of various improvements in semen preservation and AI. In addition, the conference has served to initiate collaboration among scientists worldwide. A summary of problems that remain to be investigated and solved in swine semen technology is provided.

Identification and characterisation of Kunitz-type plasma kallikrein inhibitors unique to Oxyuranus sp. snake venoms

As part of a wider study on Australian snake venom components, we have identified and characterised Kunitz-type protease inhibitors from the venoms of Oxyuranus scutellatus and Oxyuranus microlepidotus (Australian taipans) with plasma kallikrein inhibitory activity. Each inhibitor had a mass of 7 kDa and was purified from the venom as part of a protein complex. Mass spectrometry and N-terminal sequencing was employed to obtain amino acid sequence information for each inhibitor and a recombinant form of the O. scutellatus inhibitor, termed TSPI, was subsequently expressed and purified. TSPI was investigated for inhibition against a panel of 12 enzymes involved in haemostasis and estimates of the K(i) value determined for each enzyme. TSPI was found to be a broad spectrum inhibitor with most potent inhibitory activity observed against plasma kallikrein that corresponded to a K(i) of 0.057 ± 0.019 nM. TSPI also inhibited fibrinolysis in whole blood and prolonged the intrinsic clotting time. These inhibitors are also unique in that they appear to be found only in Oxyuranus sp. venoms.

Effect of corn preparation methods on dry-grind ethanol production by granular starch hydrolysis and partitioning of spent beer solids

Two corn preparation methods, rollermill flaking and hammermill grinding, were compared for efficient processing of corn into ethanol by granular starch hydrolysis and simultaneous fermentation by yeast Saccharomyces cerevisiae. Corn was either ground in a hammermill with different size screens or crushed in a smooth-surfaced rollermill at different roller gap settings. The partitioning of beer solids and size distribution of solids in the thin stillage were compared. The mean particle diameter d(50) for preparations varied with set-ups and ranged between 210 and 340 μm for ground corn, and 1180-1267 μm for flaked corn. The ethanol concentrations in beer were similar (18-19% v/v) for ground and flaked preparations, however, ethanol productivity increased with reduced particle size. Roller versus hammermilling of corn reduced solids in thin stillage by 28%, and doubled the volume percent of fines (d(50) ∼ 7 μm)in thin stillage and decreased coarse (d(50) ∼ 122 μm) by half compared to hammermilling.

Building trans-Atlantic graduate education programs in biorenewable resources

We are now faced with increasingly expensive motor fuels and agriculture has potential to partially relieve these pressures. The 2007 U.S. Energy Independence and Security Act calls for the U.S. to replace with renewable fuels about 36 billion gallons of its annual 150 billion gallon motor fuel consumption by 2022. This is a monumental task that can only be achieved by conducting innovative research to discover breakthrough technologies and by educating scientists and engineers around the world. Three European and three U.S. institutions have forged partnerships that have enabled 4-6 month graduate student and faculty exchanges, faculty and graduate student participation in two-week intensive courses in both the E.U. and U.S., and sharing of educational materials. With two years to go on a second grant, 23 U.S. students have been sent to the E.U. for 4-6 months and the E.U. has sent 29 students to the U.S. Another 38 U.S. students and 36 faculty have participated in two-week intensive programs in Europe; and five E.U. students and two faculty came to the U.S. to learn and teach, respectively, in our intensive program.

Factors affecting emulsion stability and quality of oil recovered from enzyme-assisted aqueous extraction of soybeans

The objectives of the present study were to assess how the stability of the emulsion recovered from aqueous extraction processing of soybeans was affected by characteristics of the starting material and extraction and demulsification conditions. Adding endopeptidase Protex 6L during enzyme-assisted aqueous extraction processing (EAEP) of extruded soybean flakes was vital to obtaining emulsions that were easily demulsified with enzymes. Adding salt (up to 1.5 mM NaCl or MgCl(2)) during extraction and storing extruded flakes before extraction at 4 and 30 degrees C for up to 3 months did not affect the stabilities of emulsions recovered from EAEP of soy flour, flakes and extruded flakes. After demulsification, highest free oil yield was obtained with EAEP of extruded flakes, followed by flour and then flakes. The same protease used for the extraction step was used to demulsify the EAEP cream emulsion from extruded full-fat soy flakes at concentrations ranging from 0.03% to 2.50% w/w, incubation times ranging from 2 to 90 min, and temperatures of 25, 50 or 65 degrees C. Highest free oil recoveries were achieved at high enzyme concentrations, mild temperatures, and short incubation times. Both the nature of enzyme (i.e., protease and phospholipase), added alone or as a cocktail, concentration of enzymes (0.5% vs. 2.5%) and incubation time (1 vs. 3 h), use during the extraction step, and nature of enzyme added for demulsifying affected free oil yield. The free oil recovered from EAEP of extruded flakes contained less phosphorus compared with conventional hexane-extracted oil. The present study identified conditions rendering the emulsion less stable, which is critical to increasing free oil yield recovered during EAEP of soybeans, an environmentally friendly alternative processing method to hexane extraction.

Textilinin-1, an alternative anti-bleeding agent to aprotinin: Importance of plasmin inhibition in controlling blood loss

Aprotinin has been used widely in surgery as an anti-bleeding agent but is associated with a number of side effects. We report that textilinin-1, a serine protease inhibitor from Pseudonaja textilis venom with sequence relatedness to aprotinin, is a potent but reversible plasmin inhibitor and has a narrower range of protease inhibition compared to aprotinin. Like aprotinin, textilinin-1 at 5 micromol/l gave almost complete inhibition of tissue plasminogen activator-induced fibrinolysis of whole blood clots. The activated partial thromboplastin time for plasma was markedly increased by aprotinin but unaffected by textilinin-1. In a mouse tail-vein bleeding model, intravenous textilinin-1 and aprotinin caused similar decreases in blood loss but time to haemostasis in the textilinin-treated animals was significantly shorter than in aprotinin-treated mice. Based on these data, textilinin-1 merits further investigation as a therapeutic alternative to aprotinin.

Demulsification of oil-rich emulsion from enzyme-assisted aqueous extraction of extruded soybean flakes

Extraction of soybean oil from flaked and extruded soybeans using enzyme-assisted aqueous extraction processing (EAEP) is a promising alternative to conventional hexane extraction. The efficiencies of four proteases releasing oil from extruded material were compared. Protex 51FP, Protex 6L and Protex 7L each extracted 90% of the total oil available while Protex 50FP gave similar extraction yield as the control (without enzyme treatment). During EAEP, however, a stable emulsion forms that must be broken in order to recover free soybean oil. The potential of various proteases and phospholipases to destabilize the emulsion was determined. Two enzymes, a phospholipase A2 (LysoMax) and a protease (Protex 51FP) were selected to determine the effect of enzyme concentration on demulsification. Although at a 2% concentration (w/w, enzyme/(cream+free oil)), each enzyme tested was effective in totally destabilizing the cream; the protease released significantly more free oil than did the phospholipase at concentrations less than 2%. At 0.2% concentration, 88 and 48% of free oil were obtained with the protease and phospholipase, respectively. Reducing the pH of the cream also destabilized the cream with maximum demulsification at the isoelectric point of soy proteins. These results provide destabilization strategies for the oil-rich emulsion formed during aqueous extraction processing of extruded flakes and significantly contribute to the development of this environmentally-friendly technology.

Effect of the corn breaking method on oil distribution between stillage phases of dry-grind corn ethanol production

The majority of fuel ethanol in the United States is produced by using the dry-grind corn ethanol process. The corn oil that is contained in the coproduct, distillers' dried grains with solubles (DDGS), can be recovered for use as a biodiesel feedstock. Oil removal will also improve the feed quality of DDGS. The most economical way to remove oil is considered to be at the centrifugation step for separating thin stillage (liquid) from coarse solids after distilling the ethanol. The more oil there is in the liquid, the more it can be recovered by centrifugation. Therefore, we studied the effects of corn preparation and grinding methods on oil distribution between liquid and solid phases. Grinding the corn to three different particle sizes, flaking, flaking and grinding, and flaking and extruding were used to break up the corn kernel before fermentation, and their effects on oil distribution between the liquid and solid phases were examined by simulating an industrial decanter centrifuge. Total oil contents were measured in the liquid and solids after centrifugation. Dry matter yield and oil partitioning in the thin stillage were highly positively correlated. Flaking slightly reduced bound fat. The flaked and then extruded corn meal released the highest amount of free oil, about 25% compared to 7% for the average of the other treatments. The freed oil from flaking, however, became nonextractable after the flaked corn was ground. Fine grinding alone had little effect on oil partitioning.

Improved quality of sex-sorted sperm: a prerequisite for wider commercial application

To date the only successful method to sort sperm into X- and Y-chromosome-bearing populations is the Beltsville Sperm Sexing Technology. Fertility results continue to be variable even though the technology has been used in a commercial setting for nearly a decade. This is at least partly due to the reduced lifespan of sperm after sorting and freezing. Several technical and biological factors are responsible for this problem. Furthermore, to meet economic demands, only 10-15% of the number of sperm (compared to unsexed semen) are loaded in each straw, further limiting the chances for fertilization. A new protocol for preservation of bull sperm, utilizing Sexcess shows promise in extending the lifespan of sorted bull sperm. Motility and acrosome integrity are significantly increased using Sexcess. Conception rates achieved with heifers for those bulls tested with Sexcess and using a standard AI regime give results that do not differ from results achieved using regular AI. In addition to the improvements of the sorting technology itself, we recommend a thorough pre-selection of bulls. A reliable prediction method to determine whether a bull is suitable for a sex-sorting program still does not exist. Such a test is needed, especially for "custom sorting" programs. Currently, test sorts are the only means of obtaining information about the sorting efficiency of semen from a particular bull.

Differential modulation of diet-induced obesity and adipocyte functionality by human apolipoprotein E3 and E4 in mice

OBJECTIVE

Apolipoprotein E (apoE), a key protein in lipid metabolism, is highly expressed in adipose tissues. Studies have shown that human APOE*4 is associated with a lower body mass index but with a greater risk of coronary heart disease compared with other APOE alleles. To define the isoform-specific role of apoE in regulating the expandability and functionality of adipose tissues, we investigated the effects of diet-induced obesity in mice whose endogenous Apoe gene has been replaced by either the human APOE*3 or APOE*4 allele.

RESULTS

After 8 weeks on a Western-type high-fat diet, male APOE4 mice displayed impaired tolerance to glucose and fat overload compared with APOE3 mice. Subcutaneous fat tissues in APOE4 and APOE3 mice after high fat feeding were not different. In contrast, although epididymal fat tissues in APOE4 mice gained 30% less weight during the high fat feeding than in APOE3 mice, they showed impaired insulin-stimulated glucose uptake ex vivo. Epididymal APOE4 adipocytes were larger in size than APOE3 adipocytes, and expressed reduced levels of mRNA for peroxisome proliferator-activated receptor gamma2 and adiponectin, important markers of adipocyte functionality. Adenoviral expression of apoE3 in apoE-null culture adipocytes induced adiponectin mRNA in a dose-dependent manner, but the induction was significantly blunted in cells overexpressing apoE4. However, in contrast to the apoE3-expressing cells, Glut1, but not Glut4, expression levels were positively correlated with increased apoE4 mRNA, suggesting that apoE4 expression in adipocyte interferes in insulin-sensing pathways.

CONCLUSION

Dysfunctional epididymal adipose tissues contribute to the accelerated impairment of glucose tolerance in APOE4 mice fed a Western-type diet. Our results underscore the importance of functionality of individual fat depots rather than total fat mass as a determinant for metabolic disturbance during diet-induced obesity.

Hepatocyte transplantation: A review of laboratory techniques and clinical experiences

Orthotopic liver transplantation (OLT) is standard clinical practice for patients with severe and end-stage chronic liver disease. However, the chronic shortage of donor livers and parallel growth of the transplant waiting list mean that a substantial proportion of patients die while waiting for a donor liver. Attempts to reduce the waiting list by use of split-liver and living-related live donor techniques have had some impact, but additional approaches to management are vital if the death rate is to be significantly reduced. Extensive laboratory research work and limited clinical trials have shown that hepatocyte transplantation may be useful in bridging some patients to OLT. A major limiting factor has been the shortage of mature functioning human hepatocytes, which are currently mostly obtained from livers rejected for OLT. This review examines potential hepatocyte sources, hepatocyte isolation methods and preservation protocols that have been successfully established, along with an overview of clinical results.

The Beltsville sperm sexing technology: high-speed sperm sorting gives improved sperm output for in vitro fertilization and AI

The Beltsville sperm sexing technology is currently the only effective means of altering the sex ratio of offspring in livestock. The method is based on the flow-cytometric separation of X- and Y-chromosome-bearing sperm based on X/Y DNA content difference. It is an effective means of producing progeny of predetermined sex in cattle, swine, sheep, and laboratory animals. The method involves treating sperm with a DNA-binding fluorochrome, Hoechst 33342, and flow-cytometrically sorting them into separate X and Y populations that can subsequently be used for surgical intratubal or intrauterine insemination, deep-uterine insemination, regular artificial insemination in some cases, in vitro fertilization to produce sexed embryos for transfer, and intracytoplasmic sperm injection of ova. Skewed sex ratios of 85 to 95% of one sex or the other have been repeatably achieved in most species. The method has been used worldwide to produce several hundred morphologically normal animal offspring of the predicted sex. It has also been validated in the laboratory using DNA reanalysis of the sorted sperm populations and by fluorescence in situ hybridization and PCR of individual sperm. We developed a new orienting nozzle that we have fitted to both conventional and high-speed cell sorters that have been modified for sperm sorting. Recently we completed the adaptation of the new orienting nozzle to a Cytomation MoFlo high-speed cell sorter modified for sperm. This adaptation of the nozzle has increased the overall production rate of sorted X and Y sperm from about .35 million/h to 5 or 6 million sperm/h (each population). Calves have been born from cows artificially inseminated using conventional technique and sexed sperm. In addition, numerous litters of pigs have been born after transfer of embryos produced from X or Y sorted sperm.

Biomedical informatics training for dental researchers

Dental researchers collaborating closely with biomedical informaticians have achieved many advances in oral health research, such as in mapping human genetics and addressing oral health disparities. Advances will continue to increase as dental researchers and biomedical informaticians study each others' disciplines to increase the effectiveness of their collaborative research. The combined skills will greatly increase the effectiveness of dental research. This manuscript summarizes the core of biomedical informatics curriculum (biomedical informatics knowledge, data management, and software engineering) for dental research. It also summarizes the obstacles that must be overcome for all dental research students to receive the training in biomedical informatics they require. These issues are: a lack of biomedical informatics faculty, a lack of biomedical informatics courses, and a lack of accreditation standards. Last, intra- and inter-institutional collaboration solutions are described.

Flow cytometric sperm sorting: effects of varying laser power on embryo development in swine

This study was conducted to determine fertilization rate and embryo development using the Beltsville Sperm Sexing Technology with two different laser power outputs, 25 and 125 milliwatts (mW). Freshly ejaculated boar semen was diluted; one aliquot was not stained or sorted (nonsort) and a second aliquot was stained with Hoechst 33342 and sorted as a complete population, not separated into X and Y populations (all-sort). Ovulation controlled gilts were surgically inseminated with 2 x 10(5) spermatozoa (44-46 hr after human chorionic gonadotropin (hCG)) into the isthmus of each oviduct, one oviduct receiving nonsort and the other all-sort at 25 or 125 mW. A total of 426 embryos were flushed from oviducts at slaughter 43 hr after laparotomy and prepared for determination of fertilization and cleavage rates using confocal laser microscopy for analysis of actin cytoskeleton and chromatin configuration. The percentage of fertilized eggs and embryos was less for the 25 mW all-sort compared to nonsort or the 125 mW all-sort (77.9 vs. 96.3 and 96.2%, P < 0.05). The percentage of fragmented embryos was greater for the 25 mW all-sort than the nonsort (15.2 vs. 4.5%, P < 0.05), but did not differ significantly from 125 mW all-sort mean (7.2%). The percentage of normal embryos (80.4% overall) did not differ (P > 0.05) among treatments. However, the rate of embryo development was slower (P < 0.05) after insemination with the 25 mW all-sort spermatozoa compared to nonsort spermatozoa. Embryos in the 3-4 and 5-9 cell stages for the 25-mW all-sort and nonsort were 78 and 20% vs. 49 and 50%, respectively. The embryo percentages for the 125 mW (3-4 and 5-9 cell stages, 59 and 35%) did not differ significantly (P > 0.05) from the nonsort or 25 mW all-sort. We conclude that the use of 125 mW laser power for sorting boar spermatozoa is advantageous to maintain high resolution separation and has no detrimental effect on embryo development compared to 25 mW.

The Emergency Medical Treatment and Labor Act as a federal health care safety net program

Despite the greatest economic expansion in history during the 1990s, the number of uninsured U.S. residents surpassed 44 million in 1998. Although this number declined for the first time in recent years in 1999, to 42.6 million, the current economic slow-down threatens once again to increase the ranks of the uninsured. Many uninsured patients use hospital emergency departments as a vital portal of entry into an access-impoverished health care system. In 1986, Congress mandated access to emergency care when it passed the Emergency Medical Treatment and Labor Act (EMTALA). The EMTALA statute has prevented the unethical denial of emergency care based on inability to pay; however, the financial implications of EMTALA have not yet been adequately appreciated or addressed by Congress or the American public. Cuts in payments from public and private payers, as well as increasing demands from a larger uninsured population, have placed unprecedented financial strains on safety net providers. This paper reviews the financial implications of EMTALA, illustrating how the statute has evolved into a federal health care safety net program. Future actions are proposed, including the pressing need for greater public safety net funding and additional actions to preserve health care access for vulnerable populations.

Determination of an acute no-observed-adverse-effect level (NOAEL) for copper in water

A prospective, double-blind controlled study was designed to determine the acute no-observed-adverse-effect level (NOAEL) of nausea in an apparently healthy population of 179 individuals who drank copper-containing water as the sulfate salt. Subjects were recruited at three different international sites and given a blind, randomly selected dose (0, 2, 4, 6, or 8 mg Cu/L) in a bolus of 200 ml (final total copper dose was equivalent to 0, 0.4, 0.8, 1.2, and 1.6 mg) once weekly over a consecutive 5-week period. Gastrointestinal (GI) symptoms of nausea, abdominal pain, vomiting, or diarrhea were screened for a period of up to 24 h. Nausea was the most frequently reported effect and was reported within the first 15 min of ingestion. For the combined trisite population (n=179), 8, 9, 14, 25, and 44 subjects responded positively to one or more GI symptoms at 0, 2, 4, 6, and 8 mg Cu/L, respectively. Analysis of the data demonstrated a clear dose response to the combined positive GI effects and to nausea alone. Statistically significant greater reporting of effects occurred at 6 and 8 mg Cu/L. Therefore, an acute NOAEL and lowest-observed-adverse-effect level of 4 and 6 mg Cu/L (0.8 and 1.2 mg Cu), respectively, were determined in drinking water for a combined international human population.

An X-Y paint set and sperm FISH protocol that can be used for validation of cattle sperm separation procedures

X and Y chromosome paints were developed from sorted yak chromosomes for sexing cattle spermatozoa. Clear hybridization signals were obtained for every spermatozoon using a modified sperm decondensation protocol and fluorescence in situ hybridization (FISH). The procedure was evaluated using the established Beltsville sperm sexing technology, which separates spermatozoa by flow cytometry into X- and Y-bearing fractions. Close agreement was found between the assessment of sperm separation by flow cytometry and by FISH with the X-Y paint set. The FISH method is a simple, reliable and robust procedure for assessing the effectiveness of separation of X and Y spermatozoa.

An X-Y paint set and sperm FISH protocol that can be used for validation of cattle sperm separation procedures

X and Y chromosome paints were developed from sorted yak chromosomes for sexing cattle spermatozoa. Clear hybridization signals were obtained for every spermatozoon using a modified sperm decondensation protocol and fluorescence in situ hybridization (FISH). The procedure was evaluated using the established Beltsville sperm sexing technology, which separates spermatozoa by flow cytometry into X- and Y-bearing fractions. Close agreement was found between the assessment of sperm separation by flow cytometry and by FISH with the X-Y paint set. The FISH method is a simple, reliable and robust procedure for assessing the effectiveness of separation of X and Y spermatozoa.

Complete nucleotide sequence and analysis of the locus of enterocyte Effacement from rabbit diarrheagenic Escherichia coli RDEC-1

The pathogenicity island termed the locus of enterocyte effacement (LEE) is found in diverse attaching and effacing pathogens associated with diarrhea in humans and other animal species. To explore the relation of variation in LEE sequences to host specificity and genetic lineage, we determined the nucleotide sequence of the LEE region from a rabbit diarrheagenic Escherichia coli strain RDEC-1 (O15:H-) and compared it with those from human enteropathogenic E. coli (EPEC, O127:H6) and enterohemorrhagic E. coli (EHEC, O157:H7) strains. Differing from EPEC and EHEC LEEs, the RDEC-1 LEE is not inserted at selC and is flanked by an IS2 element and the lifA toxin gene. The RDEC-1 LEE contains a core region of 40 open reading frames, all of which are shared with the LEE of EPEC and EHEC. orf3 and the ERIC (enteric repetitive intergenic consensus) sequence present in the LEEs of EHEC and EPEC are absent from the RDEC-1 LEE. The predicted promoters of LEE1, LEE2, LEE3, tir, and LEE4 operons are highly conserved among the LEEs, although the upstream regions varied considerably for tir and the crucial LEE1 promoter, suggesting differences in regulation. Among the shared genes, high homology (>95% identity) between the RDEC-1 and the EPEC and EHEC LEEs at the predicted amino acid level was observed for the components of the type III secretion apparatus, the Ces chaperones, and the Ler regulator. In contrast, more divergence (66 to 88% identity) was observed in genes encoding proteins involved in host interaction, such as intimin (Eae) and the secreted proteins (Tir and Esps). A comparison of the highly variable genes from RDEC-1 with those from a number of attaching and effacing pathogens infecting different species and of different evolutionary lineages was performed. Although RDEC-1 diverges from some human-infecting EPEC and EHEC, most of the variation observed appeared to be due to evolutionary lineage rather than host specificity. Therefore, much of the observed hypervariability in genes involved in pathogenesis may not represent specific adaptation to different host species.

Antepartum bed rest: effect upon the family

OBJECTIVE

To identify the effects of antepartum bed rest upon the family.

DESIGN

Descriptive, retrospective survey.

PARTICIPANTS

A national random selection of 89 women who had been prescribed antepartum bed rest in the hospital or at home and who contacted a high-risk pregnancy support group for information.

MAIN OUTCOME MEASURE

An open-ended questionnaire.

RESULTS

Families experienced difficulty assuming maternal responsibilities, anxiety about maternalfetal outcomes, and adverse emotional effects on the children. Child care was managed by various people across time. Child care problems included negative reactions from the children, concern about the quality of the provider, and maternal worry about care. Families also experienced financial difficulties, the majority of which were not compensated by insurance or work benefits. Almost all, 96.6%, families received some type of support during bed rest. Instrumental support was the most commonly received; however, emotional support was considered the most helpful. The least helpful type of support was that which was unreliable. The primary providers of support to the family were parents and family, followed by friends. The women reported that health care providers offered minimal support to the family.

CONCLUSION

Despite support, antepartum bed rest creates difficulties that affect the entire family and its finances.

Development of neuronal circuits and behaviors in the medicinal leech

We are studying the neuronal mechanisms responsible for establishing circuitry underlying the local bending response in the medicinal leech. Local bending replaces an embryonic behavior, circumferential indentation, during the time of initial chemical synaptogenesis in leech embryos. We found that the electrical connections among the motor neurons are established first, about 5% of embryonic time (almost 2 full days) before chemical connections form. The inhibitory connections from muscle inhibitors to muscle excitors are, we hypothesize, responsible for the emergence of local bending. We have also found that the central processes of the excitors--but not the inhibitors--have much longer central processes when their peripheral processes are kept from contacting their target muscles. This system should allow us to test ideas about how individual neurons find their appropriate targets to form functional neuronal circuits.

Regulation of IFN-gamma production following 2B4 activation in human NK cells

IFN-gamma is a cytokine that regulates various functions of the immune system. The major producers of IFN-gamma are T cells and NK cells. 2B4 is a novel activating receptor expressed on all human NK cells, a subset of CD8+ T cells, monocytes and basophils. Activation of human NK cells through surface 2B4 enhances NK cell cytolytic function and secretion of IFN-gamma. We have examined the regulation of IFN-gamma production by the human NK cell line YT upon activation through surface 2B4. Our data indicate that ligation of surface 2B4 by mAb C1.7, that specifically recognizes 2B4, induces transcriptional activation of IFN-gamma. Partial inhibition of transcription did not prevent the transcriptional upregulation of IFN-gamma. S1 nuclease protection analysis indicated that transcriptional activation as well as mRNA stability may account for the increased production of IFN-gamma by human NK cells following 2B4 stimulation.

Storage of boar semen

The problems, aspects and methods of liquid storage and freeze-thawing of boar semen are discussed and a review is given on examination of spermatozoa by the recent fluorescent staining methods.

Sexing mammalian sperm for production of offspring: the state-of-the-art

Predetermination of sex in livestock offspring is in great demand and is of critical importance to providing for the most efficient production of the world's food supply. With the changes that have taken place in animal agriculture over the past generation the application of sex preselection to production systems becomes increasingly necessary. The current technology is based on the well-known difference in X- and Y-sperm in the amount of DNA present. The method has been validated on the basis of live births, laboratory reanalysis of sorted sperm for DNA content and embryo biopsy for sex determination. The technology incorporates modified flow cytometric sorting instrumentation to sort X- and Y-bearing sperm. Resulting populations of X or Y sperm can be used in conjunction with IVF in swine and in cattle for the production of sexed embryos to be transferred to eligible recipients for the duration of gestation. It can also be used for intratubal insemination and for deep-uterine and conventional insemination in cattle. This semipractical sexing method, though currently impractical for some production systems (where large numbers of sperm are required for fertilization) could be used to provide a more flexible progeny-producing option in many livestock operations. Improvements in the production rate of sexed sperm continue as new technology is developed. High-speed sorting is one of the newer technological advances and is being used in our laboratory to increase sorted sperm throughput. With our original technology we sorted 350,000 sperm/h. We now sort 6 million of each sex, under routine conditions. Sorting only the X population results in about 18 million sperm/h. Improvements in the technology will no doubt lead to much greater usage of sexed sperm, depending on the species involved. Insemination of lower sperm numbers in cattle has proven to be an effective means of utilizing the sexing technology. Solving the problems associated with inseminating low sperm numbers in the pig would be advantageous to the utilization of sexed sperm for some type of deep artificial insemination. Such a development would also enhance the economy of using lower sperm numbers with conventional artificial insemination (AI) and aid the swine industry worldwide. The use of sexed sperm for non-ordinary applications such as endangered species, laboratory animals, hobby or pet species is also of interest and will become a part of the move to be more reproductively efficient in the next millennium. Sexed sperm on demand over the next several years will provide livestock producers with many options in seeking to improve efficiency of production and improve quality of products to enhance consumer acceptability.