Heat emission from thermal skirting boards

The performance of three hydronic skirting heating systems was investigated. The main focus of the study was to ascertain whether thermal skirting boards served by low-temperature supply flow were able to suppress strong downdraught. The evaluation was made for a two-person office room with mechanical ventilation. Computational Fluid Dynamics (CFD) simulations and three different draught rating models were employed to predict the level of thermal discomfort inside the room. CFD results were validated against several analytical calculations and four sets of experimental data presented in previous studies. Numerical simulations showed that all three skirting heating arrangements were able to cover transmission and ventilation thermal losses of the office room. Horizontal and vertical heat distribution inside the room was uniform for all heating systems. CFD simulations also showed that thermal skirting boards served by 40 and 45 °C supply flow had difficulty in reducing the velocity of the downdraught at ankle level. Consequently the draught rating in this region was around or slightly above 15% for these cases. In contrast, heat-emitting skirting boards supplied by 55 °C hot water showed a better ability to suppress downdraught, and the proportion of people sensing draught at 0.1 m above the floor was low. The conclusion of this study was that thermal performance of hydronic skirting heaters with low-temperature water supply must be improved in order to counter strong downdraughts, in particular where such systems may be combined with heat pumps of other low-valued sustainable energy sources.     

Ester-based surfactants: Are they stable enough?

Surfactants with an ester bond connecting the polar headgroup and the hydrophobic tail are common. They are easy to synthesize, they can often be made from natural raw materials and their biodegradation profile is generally good, partly due to lipase or esterase catalyzed breakdown of the ester bond in sewage plants. A labile ester bond in the molecule may cause problems, however. Surfactants are often formulated at relatively high pH and it is important that they remain intact for a given period of time. In this article we discuss alkaline hydrolysis of different types of ester-based surfactants—cationic, anionic and nonionic—and also of surfactant mixtures. We show that the ester bond in a surfactant has a different hydrolysis pattern than ester bonds in non-surface active uncharged molecules. Cationic ester-based surfactants are hydrolyzed rapidly while anionic and also nonionic ester-containing surfactants are relatively resistant to hydrolysis.     

Ability of bovine mammary macrophages to enhance proliferation of autologous blood and mammary secretion lymphocytes

Cells were obtained by centrifuging the mammary secretion of healthy udders of 19 cows during the dry-period and during mid-lactation. The suspended cells were incubated in plastic wells. Those adhered cells classified as mammary macrophages were incubated with pokeweed mitogen (PWM). Autologous peripheral blood lymphocytes were added to wells containing untreated macrophage cultures or cultures pretreated with PWM. In seven cows autologous dry-period mammary lymphocytes were added instead of blood lymphocytes. The macrophages + lymphocyte cultures were subjected to the lymphocyte stimulation test (LST). For comparison, peripheral blood lymphocytes and dry-period secretion lymphocytes were also subjected to the LST in the presence of PWM. In all cases, mitogenic responses were higher in pretreated macrophage cultures than in background control cultures. The stimulation indices (SI) showed that PWM-pretreated dry-period mammary macrophages enhanced the proliferation of autologous peripheral blood lymphocytes to a greater extent than did blood lymphocytes plus PWM (49 +/- 10 v. 30 +/- 6; P less than or equal to 0.05). Mammary macrophages taken from the same cows but during midlactation also clearly induced proliferation of autologous peripheral blood lymphocytes but to a lesser extent than dry-period macrophages (16 +/- 2 v. 49 +/- 10; 16 +/- 2 v. 30 +/- 6; P less than or equal to 0.01 and P less than or equal to 0.05). The PWM pretreatment of mammary macrophages increased the proliferation of autologous dry-period mammary lymphocytes by at least a factor of three (28 +/- 8 v. 8 +/- 2 P less than or equal to 0.05). The present results indicate that bovine mammary macrophages pretreated with PWM enhance proliferation as well as modulation of mammary and peripheral blood lymphocytes. The modulation of lymphocyte stimulation as demonstrated here in vitro, has great significance regarding aspects of local immunostimulation related to modern treatment of mastitis.     

Cleavable surfactants

Cleavable surfactants are of interest for several reasons. Above all, the development of surfactants with weak bonds deliberately built into the structure is driven by the need for improved biodegradability of amphiphiles. The breakdown may be catalyzed by enzymes, and biodegradation would be the normal mechanism in sewage plants. Alternatively, the surfactant may degrade by chemical means, e.g., induced by acid, alkali, ultraviolet (UV) light, heat, or ozone. Acid- and alkali-labile surfactants have attracted particular attention, and there is often a compromise between required stability at one stage and ease of breakdown at a subsequent stage. The paper reviews the main routes used to prepare cleavable surfactants and points out advantages and disadvantages of the different approaches. Emphasis is placed on the development during recent years. Cyclic and acyclic acetals, ketals, and ortho esters are the most important types of bonds for the preparation of acid-labile surfactants, whereas alkali-labile amphiphiles usually are based on ester bonds. The ester bond approach has been particularly important for cationic surfactants, and so-called ester quats have rapidly taken a large share of the traditional market for quats. Betaine esters constitute a special class of ester with very pronounced pH dependence. UV-labile surfactants based, for instance, on an azo bond, offer promise for the future.     

Evaluation of on-line flue gas measurements by MISiCFET and metal-oxide sensors in boilers

Metal insulator silicon carbide field-effect transistor sensors, metal-oxide sensors, and a linear Lambda sensor in an electronic nose was used to measure on-line in hot flue gases from a boiler. Flue gas from a 100-MW pellets-fuelled boiler has been used to feed the experimental setup. Several reference instruments, which measure the flue gases in parallel to the sensor array, are connected to the electronic nose. Data was collected during six weeks and then evaluated. Using principal component analysis as the data evaluation method, different operating modes for the boiler have been identified in the data set. The different modes could be described in terms of high or low O/sub 2/ and CO concentration. Furthermore, we have shown that it seems possible to use a sensor array to determine the operating mode of the boiler and, by partial least-squares models, measure the CO concentration when the boiler operates in its optimum mode.     

Does waterborne citalopram affect the aggressive and sexual behaviour of rainbow trout and guppy?

Citalopram is one of several selective serotonin reuptake inhibitors (SSRIs) commonly found in treated sewage effluents. Accordingly, there are concerns about possible adverse effects of SSRIs on aquatic organisms, particularly behavioural effects similar to those associated with SSRI use in humans. Rainbow trout fry and adult male guppies were therefore exposed to waterborne citalopram, ranging from environmentally relevant to high concentrations (1, 10, 100 μg/L) for 3-7 days. Under these experimental conditions citalopram does not appear to cause significant effects on aggression in rainbow trout fry or on sexual behaviour in male guppies. This may be explained by a relatively low uptake of citalopram from water to fish.     

Gender differences in children's play therapy themes: Comparisons of children with a history of attachment disturbance or exposure to violence.

The use of thematic content of the play of children in therapy is a common aspect to play therapy and an integral part of Thematic Play Therapy. In this project, the researchers investigated the possibility that gender and trauma history influence the play themes of children in therapy. Using the Benedict Play Theme Analysis System (BPTAS), a study of themes demonstrated by 44 children (aged 39–63 mo) participating in therapy through Head Start was conducted. The data were analyzed by comparing equally numbered groups of gender alone (male vs female), trauma history alone (attachment trauma vs attachment trauma plus exposure to violence in the history) and a combination of the possible influences (gender and trauma history). Results indicate that gender and trauma histories, as well as a possible interaction of the two influences, impact the frequency and types of themes that children play in therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The association between cigarette smoking and selected HIV-related medical conditions

OBJECTIVE: To clarify the effect of cigarette smoking on the development of conditions associated with HIV infection. DESIGN: Prospective and retrospective cohort study, with interview and examination twice a year since 1988. METHODS: Data on 516 HIV-infected men from cohorts of homosexual and bisexual men in San Francisco, Denver and Chicago, who were repeatedly interviewed and examined between 1988 and 1992, were analysed. After excluding men who did not have well-defined dates of seroconversion and those who were classified as ex- or intermittent smokers, 232 men remained for analysis: 106 were smokers and 126 were non-smokers. Univariate and Kaplan-Meier survival analyses were performed to assess the relationship between cigarette smoking and loss of CD4+ T-lymphocytes, diagnosis of any AIDS-defining illness, and specific diagnosis of Kaposi's sarcoma, Pneumocystis carinii pneumonia (PCP), oral candidiasis, hairy leukoplakia, and community-acquired pneumonia. RESULTS: By univariate analyses, cigarette smoking was not associated with clinical AIDS, loss of CD4+ cells, Kaposi's sarcoma or PCP, but was significantly associated with oral candidiasis [relative risk (RR), 1.32; 95% confidence interval (CI), 1.02-1.70], hairy leukoplakia (RR, 1.51; 95% CI, 1.15-1.99), and community-acquired pneumonia (RR, 2.62; 95% CI, 1.30-5.27). Dose-response effect was also evident for these three conditions (all P < 0.01). Kaplan-Meier survival analysis indicated no association between cigarette smoking and time of progression to clinical AIDS, Kaposi's sarcoma (KS), or PCP (P = 0.62, 0.54 and 0.11, respectively) but showed that cigarette smokers developed oral candidiasis, hairy leukoplakia, and pneumonia more quickly than non-smokers (P = 0.031, 0.006 and 0.009, respectively). CONCLUSIONS: Cigarette smoking was not associated with an increased likelihood or rate of developing KS, PCP or AIDS, but was associated with developing community-acquired pneumonia, oral candidiasis, and hairy leukoplakia in these HIV-infected men.     

A novel esterase from Saccharomyces carlsbergensis, a possible function for the yeast TIP1 gene

An extracellular esterase was isolated from the brewer's yeast, Saccharomyces carlsbergensis. Inhibition by diisopropyl fluorophosphate shows that the enzyme has a serine active site. By mass spectrometry, the molecular weight of the enzyme was 16.9 kDa. The optimal pH for activity was in the range of four to five. Esterase activity was found in beer before pasteurization, and a low level of activity was still present after pasteurization. Caprylic acid, which is present in beer, competitively inhibited the esterase. The substrate preference towards esters of p-nitrophenol indicated that the enzyme prefers esters of fatty acids from four to 16 carbon atoms. The esterase has lipolytical activity; olive oil (C-18:1), which is a classical substrate for lipase, was hydrolysed. N-terminal sequence analysis of the esterase yielded a sequence which was identical to the deduced amino acid sequence of the S. cerevisiae TIP1 gene. The esterase preparation did not appear to contain significant amounts of other proteins than Tip1p, indicating that the TIP1 gene is the structural gene for the esterase.