Hydrogen impurity in natural gem diamond

Five natural gem diamonds which included type I_A, I_B and II_A specimens, have been investigated by ion beam spectrochemical analysis (IBSCA) to determine the total hydrogen impurity concentration in the diamonds. These data were compared with that obtained from other conventional techniques such as infrared and ultraviolet absorption spectroscopy, electron spin resonance and transmission electron microscopy (TEM). IBSCA indicated that all the specimens appeared to contain 1 at. % of hydrogen contrary to the infrared evidence. The highest hydrogen concentration was recorded by a type I_B specimen which contained small ( 3nm) bubbles. The hydrogen concentration did not correlate with any defect within the specimens, for example the {100} planar faults, and appeared to be a general impurity. No evidence was found to suggest that inclusions were responsible for the impurity.     

Fractionation of menhaden oil ethyl esters using supercritical fluid CO2

Supercritical fluid CO₂ was used to fractionate menhaden oil fatty acid ethyl esters to obtain concentrates of the esters of allcis-5,8,11,14,17-eicosapentaenoic acid (EPA) and allcis-4,7,10,13,16,19-docosahexaenoic acid (DHA). Separation of the ethyl esters was found to occur primarily by carbon number, thus limiting the degree to which the ethyl esters of EPA and DHA could be concentrated. Urea fractionation of whole esters in order to remove saturates, monoenes and dienes prior to fractionation with supercritical fluid CO₂ resulted in concentrates of EPA and DHA in purities exceeding 90%. Several criteria are given for the selection of crude oils in order to maximize both purity and yield of concentrates.     

Optically injected logic circuits for remote-powered systems on a chip

This paper reviews the concept of optically injected logic circuits and investigates their implementation in nanometer CMOS technologies. Optically injected circuits are powered via an optical beam, i.e. they do not require a local power supply and distribution network. A complete set of digital cells has been designed and simulated, and key building blocks of the logic family have been fabricated and tested in a standard 180 nm CMOS technology. The paper also discusses the design and implementation of optically injected circuits for clock distribution, input/output, analog-to-digital and digital-to-analog conversion. All these circuits are immediately applicable in wireless biomedical implants or contactless smart cards. They can also be used in other systems-on-chip (SoC), in which very low power operation can be replaced by remote-powered operation.     

Number and distribution of bacteria on some beef carcasses at selected abattoirs in some member states of the European communities

In seven member countries of the European Communities, three abattoirs were visited on three occasions in each of two surveys and at each visit ten beef carcasses were sampled, before chilling, at defined sites on the neck, brisket, forerib and medially on the round. In Survey I, samples were plated for total viable count (TVC) at 30° (ISO 2293) and Enterobacteriaceae at 37° (ISO 5552); in Survey II only TVCs were made. This paper is confined to analyses of the TVCs in the two surveys. Data from each country were analysed separately as sampling methodology may not have been sufficiently reproducible by different workers to allow between-countries comparison. Variations among visits to particular abattoirs and abattoir × site interactions made comparisons among abattoirs invalid within five of the seven countries. To effectively monitor differences between abattoirs within most countries it would be necessary to make more than three visits to each abattoir. Despite abattoir × site interactions in three countries in Survey I and four countries in Survey II, comparisons between sites were generally valid because of the consistent high contamination of the brisket. In the remainder of countries the abattoir × site interaction was too large to allow valid comparisons between sites. It is recommended that at least three or four sites are sampled in future surveys as only one site per carcass would underestimate the number of more heavily contaminated carcasses.     

Reductive cleavage of the disulfide bonds of the collagen IV noncollagenous domain in aqueous sodium dodecyl sulfate: absence of intermolecular nondisulfide cross-links

OBJECTIVES: The goal of this study was to develop an accurate, simplified proximal isovelocity surface area (PISA) method for calculating volume flow rate using lower blue-red interface velocity produced by a color Doppler zero baseline shift technique. BACKGROUND: The Doppler color proximal isovelocity surface area method has been shown to be accurate for calculating the volume flow rate (Q) across a narrowed orifice by the formula Q = PISA x Blue-red interface velocity. A hemispheric model is generally used to calculate proximal isovelocity surface area (PISA = 2 pi a2, where a = the radius corresponding to the blue-red interface velocity). Although a hemispheric model is simple, requiring measurement of one radius, it may underestimate the actual volume flow rate because, in the general case, the shape of a proximal isovelocity surface area is hemielliptic. Although a hemielliptic model is generally more accurate for calculating proximal isovelocity surface area, it is more complex, requiring measurement of two orthogonal radii. METHODS: Sixteen in vitro constant flow model studies were performed using planar circular orifices (diameter range 6 to 16 mm). The blue-red interface velocity was changed from 3 to 54 cm/s using color Doppler zero baseline shift. RESULTS: 1) With decreasing blue-red interface velocity, the size of the proximal isovelocity surface area was increased, and its shape changed from hemielliptic to hemispheric. 2) With the blue-red interface velocity in the range 11 to 15 cm/s, the proximal isovelocity surface area became nearly hemispheric; however, it was difficult to determine the blue-red interface radius at a blue-red interface velocity < 10 cm/s because of interface fluctuations. 3) Calculated volume flow rate using the hemispheric proximal isovelocity surface area model with a single radius was relatively accurate at a blue-red interface velocity of 11 to 15 cm/s (mean percent difference from actual volume flow rate was -3.6%). CONCLUSIONS: Because the shape of the proximal isovelocity surface area is nearly hemispheric at a blue-red interface velocity of 11 to 15 cm/s, volume flow rate can be accurately calculated in this proximal isovelocity surface area interface velocity range (produced by zero baseline shift) by measuring a single-interface radius. This approach should be clinically useful for calculating the volume flow rate across stenotic and regurgitant valves and across shunt defects.     

Correlation of apomorphine- and amphetamine-induced turning with nigrostriatal dopamine content in unilateral 6-hydroxydopamine lesioned rats

In the unilateral 6-hydroxydopamine (6-OHDA)-lesioned rat model of Parkinson's disease, controversy exists concerning the use of apomorphine- or D-amphetamine-induced rotations as reliable indicators of nigrostriatal dopamine depletion. Our objective was to evaluate which, if either, drug-induced behavior is more predictive of the extent of nigrostriatal dopamine depletion. Fischer 344 and Sprague-Dawley rats were unilaterally injected with 9 micrograms/4 microliters/4 min 6-hydroxydopamine into the medial forebrain bundle. The animals were behaviorally tested with apomorphine (0.05 mg/kg, s.c.) and D-amphetamine (5.0 mg/kg, s.c.). Following testing, the brains were removed and the right and left striata, substantia nigra and ventral tegmental area were dissected free and quickly frozen at -70 degrees C for analysis of catecholamine content by high performance liquid chromatography coupled with electrochemical detection. Our results indicate that an animal which has greater than a 90% depletion of dopamine in the striatum might not rotate substantially on apomorphine, without a concomitant depletion of > 50% of the DA content in the corresponding substantia nigra. No correlations were seen involving depletions of the ventral tegmental area and the extent of the lesions to the striatum. Submaximally lesioned (75-90% depleted) rats were found to rotate on D-amphetamine but not on apomorphine. In addition, control rats that did not receive lesions were often seen to rotate extensively on D-amphetamine. We therefore conclude that maximal lesions of the striatum and substantia nigra are required to generate rotations demonstrable with low dose apomorphine but not with D-amphetamine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reduced quality of life in survivors of acute respiratory distress syndrome compared with critically ill control patients

CONTEXT: Health-related quality of life (HRQL) is reduced in patients who survive acute respiratory distress (ARDS), but whether this decline in HRQL is caused by ARDS or other aspects of the patient's illness or injury is unknown. OBJECTIVE: To determine if there are differences in the HRQL of ARDS survivors and comparably ill or injured controls without ARDS. DESIGN: Prospective, matched, parallel cohort study. SETTING: A 411-bed municipal medical and regional level I trauma center. PATIENTS: Seventy-three pairs of ARDS survivors and severity-matched controls with the clinical risk factors for ARDS of sepsis and trauma admitted between January 1, 1994, and July 30, 1996. MAIN OUTCOME MEASURES: The HRQL of ARDS survivors and controls, assessed by generic and pulmonary disease-specific HRQL instruments (Medical Outcomes Study 36-Item Short Form Health Survey, Standard Form [SF-36] and St George's Respiratory Questionnaire [SGRQ], respectively). RESULTS: Clinically meaningful and statistically significant reductions in HRQL scores of ARDS survivors (n = 73) were seen in 7 of 8 SF-36 domains and 3 of 3 SGRQ domains compared with matched controls (P<.001 for all reductions). The largest decrements in the HRQL were seen in physical function and pulmonary symptoms and limitations. Analysis of trauma-matched pairs (n = 46) revealed significant reductions in 7 of 8 SF-36 domains (P< or =.02) and 3 of 3 SGRQ domains (P< or =.003). Analysis of sepsis-matched pairs (n = 27) revealed significant reductions in 6 of 8 SF-36 domains (P< or =.05) and 3 of 3 SGRQ domains (P< or =.002). CONCLUSIONS: Survivors of ARDS have a clinically significant reduction in HRQL that appears to be caused exclusively by ARDS and its sequelae. Reductions were primarily noted in physical functioning and pulmonary disease-specific domains.