Cyclic fatty acids: Removal of aromatic acids formed during hydrogenation

Monomeric fatty acids derived from the alkali treatment of linseed oil at temperatures above 200C contain cyclic (1,2-disubstituted cyclohexadiene) and straight-chain fatty acids. Hydrogenation converts cyclic to liquid, saturated cyclic acids that can be recovered in a pure state by crystallization. During hydrogenation (palladium catalyst) some of the unsaturated cyclic acids form aromatic fatty acids by loss of hydrogen and under some conditions are not subsequently hydrogenated. It was necessary to establish conditions for complete hydrogenation since color and oxidative stability at high temperature are inversely related to aromatic content. Previously, the preparation of cyclic acids free of aromatic acids was by hydrogenation in the presence of a high concentration of acetic acid. A further study of reaction variables established conditions to make saturated cyclic fatty acids free of aromatic without acetic acid. Factors favoring the elimination of aromatic acids include a high catalyst concentration, high temperature and pressure, good hydrogen dispersion in the liquid and good agitation. Presented in part at AOCS Meeting, New Orleans, April 1964. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Nutritional Calcium Supply Dependent Calcium Balance,Bone Calcification and Calcium Isotope Ratios in Rats

Serum calcium isotopes (δ^44/42Ca) have been suggested as a non-invasive and sensitive Ca balance marker. Quantitative δ^44/42Ca changes associated with Ca flux across body compartment barriers relative to the dietary Ca and the correlation of δ^44/42Ca_Serum with bone histology are unknown. We analyzed Ca and δ^44/42Ca by mass-spectrometry in rats after two weeks of standard-Ca-diet (0.5%) and after four subsequent weeks of standard- and of low-Ca-diet (0.25%). In animals on a low-Ca-diet net Ca gain was 61 ± 3% and femur Ca content 68 ± 41% of standard-Ca-diet, bone mineralized area per section area was 68 ± 15% compared to standard-Ca-diet. δ^44/42Ca was similar in the diets, and decreased in feces and urine and increased in serum in animals on low-Ca-diet. δ^44/42Ca_Bone was higher in animals on low-Ca-diet, lower in the diaphysis than the metaphysis and epiphysis, and unaffected by gender. Independent of diet, δ^44/42Ca_Bone was similar in the femora and ribs. At the time of sacrifice, δ^44/42Ca_Serum inversely correlated with intestinal Ca uptake and histological bone mineralization markers, but not with Ca content and bone mineral density by µCT. In conclusion, δ^44/42Ca_Bone was bone site specific, but mechanical stress and gender independent. Low-Ca-diet induced marked changes in feces, serum and urine δ^44/42Ca in growing rats. δ^44/42Ca_Serum inversely correlated with markers of bone mineralization.     

Telomerase activity in female and male rat germ cells undergoing meiosis and in early embryos

Telomerase is a ribonucleoprotein that synthesizes telomeric DNA at the ends of eukaryotic chromosomes. It has been hypothesized that telomerase activity is necessary for cellular immortalization and that telomerase activity is present in cells of germline origin. The objective of the present study was to determine the level of telomerase activity in the following rat cells: 1) oocytes from follicles at different stages of development, 2) spermatogenic cells, and 3) early embryos. Telomerase activity was quantitated using a recently developed, sensitive polymerase chain reaction-based assay and a human kidney cell line (293) as a standard. Telomerase activity was found in oocytes from early antral and preovulatory follicles, as well as in ovulated oocytes. The level of enzyme activity in early antral and preovulatory follicles was comparable to that of the 293 cells, while levels in ovulated oocytes were 50-fold lower. Telomerase activity was present in even lower levels in pachytene spermatocytes and round spermatids, and no telomerase activity was detected in spermatozoa from either the caput or the cauda epididymis. After fertilization, telomerase activity was present in 4-cell embryos. Telomerase activity was also detected in several rat somatic tissues. These data demonstrate that telomerase activity is present in germ cells at several stages of differentiation, with the exception of spermatozoa, and suggest that telomerase activity may be important during meiosis. The high levels of telomerase activity in individual oocytes may serve as a marker for monitoring the effects of hormonal agents, aging, and toxins on oocyte quality.     

Native data representation: An efficient wire format for high-performance distributed computing

New trends in high-performance software development such as tool- and component-based approaches have increased the need for flexible and high-performance communication systems. When trying to reap the well-known benefits of these approaches, the question of what communication infrastructure should be used to link the various components arises. In this context, flexibility and high-performance seem to be incompatible goals. Traditional HPC-style communication libraries, such as MPI, offer good performance, but are not intended for loosely-coupled systems. Object- and metadata-based approaches like XML offer the needed plug-and-play flexibility, but with significantly lower performance. We observe that the flexibility and baseline performance of data exchange systems are strongly determined by their wire formats, or by how they represent data for transmission in heterogeneous environments. After examining the performance implications of using a number of different wire formats, we propose an alternative approach for flexible high-performance data exchange, Native Data Representation, and evaluate its current implementation in the portable binary I/O library.     

Publish-subscribe for high-performance computing

High-performance computing could significantly benefit from publish-subscribe communication, but current systems don't deliver the kind of performance required by applications in that domain. In response, the authors developed Echo, a high-performance event-delivery middleware designed to scale to the data rates typically found in grid environments. This article provides an overview of Echo, the infrastructure on which it's built, and the techniques used to implement it.     

Bilateral percutaneous balloon angioplasty of the axillary arteries in a patient with giant cell arteritis and upper extremity ischemic symptoms not responsive to corticosteroids

Giant cell arteritis (GCA) is well known to present with protean manifestations. We describe a 68-year-old woman with persistent upper extremity ischemic symptoms despite adequate treatment for GCA. She underwent successful balloon angioplasty of bilateral axillary artery stenosis. To our knowledge this is the first case utilizing this technique in GCA. Our case highlights the rare but important circumstances under which interventional techniques both surgical and nonsurgical need to be considered in cases of GCA with arterial occlusion not responsive to corticosteroid therapy.     

Water recycle method for washing alkali-refined soybean oil

Vegetable oil refineries are faced today with cutting down on pollution caused by their waste water. A method was developed for washing alkali-refined soybean oil with treated, recirculated wash water. In this method, wash water passes through a cation exchange resin that removes Na, and the slightly acid water goes back into the system for continuous reuse. The disposal problem arising from current industrial practice can be largely or entirely avoided by this reuse method. The new method might well be applicable to other oilseed processing. Batch tests were first made by mixing water, alkalirefined soybean oil and cation exchange resin. The amount of Na in the soybean oil was reduced from 34 to less than 0.5 ppm. In continuous washing tests conducted in a Podbielniak contactor with water treated by a cation exchange resin, the Na level of a commercially refined oil (not water-washed) was reduced from 34 ppm to less than 1.5 ppm. These results are comparable to or better than those obtained by the conventional method of employing fresh water for washing soybean oil. Presented at the AOCS Meeting, Minneapolis, October 1969. Res. Dev. Div., ARS, USDA.     

A transactional perspective on critical thinking

The quality of thinking has received much attention within the last decade. The scientific inquiry models introduced by Dewey, Dressel and Mayhew, and Watson-Glaser have been expanded to incorporate such aspects as reflection, development, attitude, skill, and knowledge domain. Dichotomies between critical and creative thinking have been eased. While this scholarship on thinking has been impressive, current pedagogy remains focused on scientific inquiry and on received knowledge. In nursing the learning paradigm has been similarly focused for the past 3 decades on a scientific inquiry model and received knowledge. The major cognitive approach to education and practice has been the nursing process, a linear problem-solving paradigm equivalent to the scientific method. This linear approach does not fully account for how nurses think and make judgments in clinical practice. The Transactional Model of Critical Thinking presented in this paper addresses the complexity of critical thinking in nursing. The model provides an educative and novel vision of thinking based on a transactional view of the individual, personal attributes, and the environment. Components and elements of the model are described and suggestions made for teaching-learning and for evaluation of critical thinking in nursing.     

Light coupling from a semiconductor laser into a polarisation-maintaining single-mode fibre

For laser to polarisation-maintaining fibre coupling we propose the insertion of a short piece of normal single-mode fibre. As a result a power coupling loss of 2.8 dB is obtained, whereas additional crosspolarisation is very small compared with the unwanted polarisation excitation of the laser itself.     

Randomized phase II study of two schedules of topotecan in previously treated patients with ovarian cancer: a National Cancer Institute of Canada Clinical Trials Group study

PURPOSE: As topotecan is S-phase-specific, its efficacy is likely schedule-dependent. Therefore, a randomized study using a "pick the winner" design was undertaken to compare two schedules in patients with recurrent ovarian cancer. PATIENTS AND METHODS: Patients with recurrent epithelial ovarian cancer previously treated with no more than two separate regimens of chemotherapy, one of which had to be platinum-containing, were randomized to either topotecan 1.5 mg/m2 intravenously (i.v.) over 30 minutes daily for 5 days repeated every 21 days (arm A, the standard arm), or topotecan 1.75 mg/m2 as a 24-hour infusion once a week for 4 weeks repeated every 6 weeks (arm B, the experimental arm). RESULTS: Sixty-six patients were eligible and 63 were assessable for response. The response rate in arm A was 22.6% (95% confidence interval [CI], 9.6% to 41.2%), which was significantly superior to that in arm B, 3.1% (95% CI, 0.1% to 16%) (P = .026). The regimens were not equitoxic, with 94% of patients on arm A experiencing grade 3 or 4 granulocytopenia as opposed to 52% on arm B. CONCLUSION: The weekly 24 hour infusion of topotecan at 1.75 mg/m2 was ineffective in relapsed ovarian cancer. The daily-times-five schedule remains the schedule of choice. As the regimens were not equitoxic, one cannot differentiate between an ineffective schedule and an ineffective dose as the reason for the differing response rates. However, the degree of myelotoxicity that already occurs will preclude any substantially higher dosing with the weekly regimen.