Hygrothermal analysis of wooden frame and cross-laminated timber walls for energy efficiency and durability in Bhutanese climate

Much research on building envelopes and energy efficiency in Bhutan has been done, however the importance of hygrothermal analysis on timber envelopes has received limited attention. Is constructing all residential buildings with timber in the Bhutanese climate feasible? A simulation-based methodology of white box modeling software Design-Builder and WUFI Pro is used to analyze the feasibility of timber construction. Typical Bhutanese buildings are more energy in-efficient due to poor thermal and leaky buildings envelope. The baseline building has an energy demand of 269.5 kWh/m2a in cold climates and 193.0 kWh/m2a in warm and humid climates. The proposed building, with timber frame and cross-laminated timber (CLT), has energy demand of 93.7 kWh/m2a by following prescriptive ASHRAE standards and 85.8 kWh/m2a by using Passivhaus building envelope in cold climates, with energy savings of 51% and 62%, respectively. For warm and humid climates, the proposed building has energy demand of 168.7 kWh/m2a by following prescriptive ASHRAE standard and 151.2 kWh/m2a for Passivhaus standard, saving 11% and 18% energy, respectively. For hygrothermal performance 24 configurations have been studied for WFW and 72 configurations for CLT wall. 88% of the WFW fail in the cold climate except for those configurations which have both vented and vapor barrier. However, warm and humid weather does not give any moisture problem to WFW. The CLT assemblies pass the durability test in all the simulated configurations including XPS,EPS, MW insulation. The conclusion of the research is simulation based, and further experimental validation is required

Effect of cimetidine, ranitidine, famotidine and omeprazole on hepatocyte proliferation in vitro

Recently reports have indicated that both cimetidine and ranitidine delay cell proliferation in rats following 70% partial hepatectomy and result in an increased mortality following this procedure. The present study was designed to determine whether three H2 blocking agents (cimetidine, ranitidine, famotidine) and a new, powerful antisecretory drug (omeprazole) specifically influence hepatocyte proliferation in primary culture. Hepatocytes were isolated from livers of normal male rats by the standard collagenase perfusion technique. Hepatic DNA synthesis and percent of labelled nuclei were determined after 48 h incubation. Hepatocytes in culture were incubated with the H2 blocking agents and omeprazole or with different concentrations of serum obtained from shamoperated or 70% hepatectomized rats treated or not with the same agents. Rats were injected intraperitoneally at 8:00 a.m. on two consecutive days. In hepatectomized rats, the first dose was injected at 8:00 a.m. immediately after surgery, the second, 24 h later. The serum of sham-operated or 70% hepatectomized rats that did not receive drugs served as control. No changes in DNA synthesis, percentage of labelled nuclei and transaminase were detected when the agents were added to the hepatocytes in culture at concentrations within the effective pharmacological dosage and 30 times higher. Similarly, no changes in these parameters were obtained when different concentrations of serum obtained from sham-operated rats treated with H2 blocking agents or omeprazole were added to the basal culture medium. However, a significant inhibition of DNA synthesis and of percentage of labelled nuclei was observed when hepatocytes were incubated in the presence of serum from 70% hepatectomized rats that had been treated with cimetidine or with ranitidine. The serum of 70% hepatectomized rats treated with famotidine and omeprazole had no effect on hepatocyte proliferation in vitro. No effect on transaminase was found in these conditions. © 1989

Antimicrobial Property of Hydrocolloid Impression Material Incorporated with Silver Nanoparticles Against Staphylococcus Aureus

Dental impressions can easily become contaminated with patient’s blood and saliva which are capable of transmitting infectious diseases to dental personnel. The addition of antimicrobial agents into impression materials could be effective in reducing the chances of cross-infection. Silver nanoparticles have been applied in dentistry as a potent antimicrobial agent. This study aims to evaluate the in vitro antimicrobial efficacy of silver nanoparticles incorporated to irreversible hydrocolloid impression material against Staphylococcus aureus. Silver nanoparticles (AgZrPO4, National Direct Network Company, Thailand) at concentrations of 0.25%, 0.50%, 1.00% and 1.50% w/w were added to powder of impression materials (Kromopan, Lascod, Ilaty). Impression material samples were prepared on sterile plate in accordance with manufacturer’s instruction. After setting, a 100 microliter of S. aureus ATCC6538 suspension (106 cells/mL) were inoculated on the surface of the impression sample and left for 10 minutes. The amount of S. aureus on the surface was quantified using imprint technique on Mannitol Salt agar. Impression materials incorporated with AgZrPO4 showed antimicrobial property against S. aureus (up to 95% reduction) compared with control (impression material without AgZrPO4). Even though the mechanism of antimicrobial action was not clearly understood, AgZrPO4 incorporated to impression material was demonstrated to possess an inhibitory effect against pathogenic bacteria. Further studies are needed to investigate physical properties of the material and the clinical usage

Antimicrobial Property of Hydrocolloid Impression Material Incorporated with Silver Nanoparticles Against

Dental impressions can easily become contaminated with patient’s blood and saliva which are capable of transmitting infectious diseases to dental personnel. The addition of antimicrobial agents into impression materials could be effective in reducing the chances of cross-infection. Silver nanoparticles have been applied in dentistry as a potent antimicrobial agent. This study aims to evaluate the in vitro antimicrobial efficacy of silver nanoparticles incorporated to irreversible hydrocolloid impression material against Staphylococcus aureus. Silver nanoparticles (AgZrPO4, National Direct Network Company, Thailand) at concentrations of 0.25%, 0.50%, 1.00% and 1.50% w/w were added to powder of impression materials (Kromopan, Lascod, Ilaty). Impression material samples were prepared on sterile plate in accordance with manufacturer’s instruction. After setting, a 100 microliter of S. aureus ATCC6538 suspension (106 cells/mL) were inoculated on the surface of the impression sample and left for 10 minutes. The amount of S. aureus on the surface was quantified using imprint technique on Mannitol Salt agar. Impression materials incorporated with AgZrPO4 showed antimicrobial property against S. aureus (up to 95% reduction) compared with control (impression material without AgZrPO4). Even though the mechanism of antimicrobial action was not clearly understood, AgZrPO4 incorporated to impression material was demonstrated to possess an inhibitory effect against pathogenic bacteria. Further studies are needed to investigate physical properties of the material and the clinical usage

Adenylyl Cyclase Type 6 Overexpression Selectively Enhances ß-Adrenergic and Prostacyclin Receptor Mediated Inhibition of Rat Cardiac Fibroblast Function Due to Co-Localization in Lipid Rafts

Cardiac fibroblasts produce and degrade extracellular matrix and are critical in regulating cardiac remodeling and hypertrophy. Fibroblasts are activated by factors such as transforming growth factor β and inhibited by agents that elevate 3′,5′-cyclic adenosine monophosphate (cAMP) levels. cAMP signal generation and response is known to be compartmentalized in many cell types in part through the colocalization of receptors and specific adenylyl cyclase isoforms in lipid rafts and caveolae. The present study sought to define the localization of key G protein-coupled receptors with adenylyl cyclase type 6 (AC6) in lipid rafts of rat cardiac fibroblasts and to determine if this colocalization was functionally relevant. We found that cardiac fibroblasts produce cAMP in response to agonists for β-adrenergic (isoproterenol), prostaglandin EP2 (butaprost), adenosine (adenosine-5′-N-ethylcarboxamide, NECA), and prostacyclin (beraprost) receptors. Overexpression of AC6 increased cAMP production stimulated by isoproterenol and beraprost but not by butaprost or NECA. A key function of fibroblasts is the production of collagen. Isoproterenol- and beraprostmediated inhibition of collagen synthesis was also enhanced by AC6 overexpression, while inhibition by butaprost and NECA were unaltered. Lipid raft fractions from cardiac fibroblasts contain the preponderance of β-adrenergic receptors and AC6 but exclude EP2 receptors. While we could not determine the localization of native prostacyclin receptors, we were able to determine that epitope-tagged prostanoid IP receptors (IPR) expressed in COS7 cells did localize, in part, in lipid raft fractions. These findings indicate that IP receptors are expressed in lipid rafts and can activate raft-localized AC isoforms. AC6 is completely compartmentized in lipid raft domains where it is activated solely by coresident G protein-coupled receptors to regulate cardiac fibroblast function