Identification of photoluminescence features of an epoxy resin based on components features and curing effects

Photoluminescence features in a commercial grade cured DGEBA-based epoxy resin have been investigated with as objective to determine which of the material compounds are responsible for cured resin emissions. The origin of the bands has been approached by considering photoluminescence of base resin and hardener taken separately, of their mixture, and in the course of curing. Most of the bands observed in the cured resin could be interpreted based on those found in the components taken separately. Fluorescence of the cured resin appears dominated by two broad bands that are characteristic of the hardener and exhibits a blue shift by up to 30 nm in the course of curing which could be used for cure monitoring purpose of the investigated system. Fluorescence of the base resin is clearly detected in the resin cured with tertiary amine as catalyser. However, it is very weak if the catalyser is not added. Two phosphorescence processes have been isolated in the cured resin, one of them being related to the base resin. Finally, a chemiluminescence spectrum has been recorded in the course of curing, which has been related to either curing-related reactions or to an oxidation process.     

Gag rules and trade secrets in managed care contracts. Ethical and legal concerns

Gag rules-clauses in managed care contracts that prevent physicians from disclosing information that the plan may find disparaging, but that could relate directly to the patient's health-have recently been the subject of ethical condemnation and legislative prohibition. Another serious problem in managed care contracts, trade secrets, or guidelines and quality assurance mechanisms that are imposed on physicians while their origins are shrouded in proprietary secrecy, have by contrast received little attention. Responses to these ethical challenges to the physician's integrity must involve individual physicians, managed care organizations, professional organizations, and public policymakers.     

V antigen-polyhistidine fusion peptide: binding to LcrH and active immunity against plague

The structural gene for V antigen (lcrV) is known to be encoded within the lcrGVH-yopBD operon of the approximately 70-kb low-calcium-response or Lcr plasmid of Yersinia pestis. This 37-kDa monomeric peptide was reported to provide active immunity in mice, suppress inflammatory cytokines, and regulate expression of the low calcium response (Lcr+). Here we describe pVHB62, encoding a polyhistidine-V antigen fusion peptide (Vh) and linked LcrH. Vh underwent degradation from both the C terminus and N terminus during classical chromatographic fractionation but remained intact within two compartments during Ni2+ affinity chromatography. The first was homogeneous, capable of active immunization (mouse intravenous 50% lethal dose, > 10(7) bacteria), and stable at 4 degrees C. The second remained bound to the affinity column but could be eluted as a mixture of Vh, LcrH, and low-molecular-weight material by application of 6 M guanidine HCl. This mixture was dialyzed, denatured in 8 M urea, and again applied to the affinity column, which then hound Vh but not LcrH. The latter was recovered and renatured, and low-molecular-weight material was removed by biochemical fractionation. The resulting homogeneous LcrH bound protein AN antigen fusion peptide but not protein A in a sandwich enzyme-linked immunosorbent assay, and this reaction was inhibited by Vh. These observations indicate that LcrH normally binds V antigen in bacterial cytoplasm and suggest that only free LcrH down-regulates expression of the low calcium response.     

Microsatellite loci for stringless bees

What ethical concerns regarding the application of new antidementia compounds are pertinent to the best interests of patients with Alzheimer's disease and their caregivers? Based on collected preliminary anecdotal accounts, these concerns are important and should be considered carefully by clinicians, researchers, and families.     

Differential class III and glibenclamide effects on action potential duration in guinea-pig papillary muscle during normoxia and hypoxia/ischaemia

1. Microelectrode recording techniques were used to study the effects of several potassium channel blockers which are considered to be Class III antiarrhythmic compounds. The effects of (+)-sotalol, UK-66,914, UK-68,798 and E-4031 on action potential duration (APD) were determined in guinea-pig isolated papillary muscles. The compounds were evaluated under normoxic or hypoxic/ischaemic conditions at 36.5 degrees C and compared to glibenclamide, which is considered to be a blocker of ATP-dependent potassium channels. Prolongation of action potential duration at 90% repolarization (APD90) was taken as an indirect measure of potassium channel blockade. 2. Under normoxic conditions, the Class III compounds prolonged APD in a concentration-dependent manner. According to EC15 values, the order of potency of the Class III compounds was found to be UK-68,798 > E-4031 > UK-66,914 > (+)-sotalol. Glibenclamide did not significantly prolong APD90 under normoxic conditions. 3. Perfusion with an experimental hypoxic or ischaemic bathing solution produced qualitatively similar effects on action potentials. Over a period of 20-25 min in either of the experimental solutions, there was a small decrease in action potential amplitude (APA) and a prominent shortening of APD. The ischaemic solution also depolarized the resting membrane potential by about 15 mV. 4. (+)-Sotalol and UK-66,914 did not reverse the shortening of APD induced by perfusion with hypoxic Krebs solution. High concentrations of glibenclamide (10 microM) and UK-68,798 (30 and 60 microM) partially reversed the hypoxia-shortened APD. Glibenclamide was more potent and exhibited a greater time-dependent action than UK-68,798. 5. During experimental ischaemia, the Class III compound E-4031 (10 microM, n = 7) produced small, but significant, increases in the APD90 (11 +/-3 ms after 20 min) which were not clearly time-dependent(14 +/- 4 ms after 30 min). UK-68,798 (10 microM) also produced a small, but insignificant, increase in APD90(12 =/-6 ms at 20 min, n = 4). Higher concentrations of UK-68,798 (30 and 60 microM, n = 4) did not produce a consistently significant increase in APD90 during ischaemia: significance was only attained after 20 min in the presence of 60 microM UK-68,798 (24 +/- 12 ms). However, in marked contrast to the effects of the Class III compounds, glibenclamide (10 microM) produced large time-dependent increases in ischaemic APD90 (34 +/- 11 ms at 7 min, n = 9) which were significant 15 min or more after drug addition(52 +/- 12 ms at 20 min, n = 7; 74 +/- 5 ms at 30 min, n = 6).6. The present microelectrode data suggest that blockers of ATP-dependent potassium channels, such as glibenclamide, might prove to be more effective than Class III compounds against ischaemia-induced shortening of cardiac action potentials.     

The gene encoding human glutathione synthetase (GSS) maps to the long arm of chromosome 20 at band 11.2

Two forms of glutathione synthetase deficiency have been described. While one form is mild, causing hemolytic anemia, the other more severe form causes 5-oxo-prolinuria with secondary neurological involvement. Despite the existence of two deficiency phenotypes, Southern blots hybridized with a glutathione synthetase cDNA suggest that there is a single glutathione synthetase gene in the human genome. Analysis of somatic cell hybrids showed the human glutathione synthetase gene (GSS) to be located on chromosome 20, and this assignment has been refined to subband 20q11.2 using in situ hybridization.     

Effects of amount of whole cottonseed on intake, digestibility, and physiological responses of dairy cows

In Experiment 1, 27 lactating cows were fed complete rations ad libitum of 0, 15, and 30% whole cottonseed to examine the effects on intake, digestibility, blood gases, and blood metabolites. Dry matter intake declined linearly with increased cottonseed, but because of greater energy density, calculated net energy for lactation intake was not depressed significantly. Ether extract, crude protein, and calcium digestibility increased with cottonseed in the diet. Respiration rates declined with dry matter intake and increased cottonseed feeding; some blood gases were influenced by cottonseed feeding but not in a detrimental way. No data among 13 blood metabolites indicated effects of gossypol toxicity with 30% whole cottonseed in the diet. In Experiment 2, 24 dry, nonpregnant Holstein cows were offered complete rations ad libitum of 15, 35, and 55% whole cottonseed to measure responses in intake, respiration rates, and blood metabolites. The highest cottonseed diet significantly depressed intake of both dry matter and calculated net energy for lactation. Maximum dry matter from cottonseed eaten by an individual was 8.4 kg/d (average for 1 wk). Respiration rates declined parallel to intake. No evidence for gossypol toxicity was seen among data of 11 metabolites in blood.     

An X-ray study of particulate solids flow in a cylindrical bunker

The noise generated by a ball mill during a batch grinding operation is investigated and the results show that, for a given ore, the noise levels may vary with time of grind, ore charge weight and mill speed. The role of the ore in absorbing noise energy is suggested as a possible control variable for the grinding process and as an indicator of product size distribution. The relationship between ore types and mill noise is also examined and, under conditions of wet grinding, it is demonstrated that mill noise analysis can indicate ore type and may have a possible use as a grindability-type parameter.