Modelling the impact of temperature on summer electricity consumption in Kuwait

Monthly electricity consumption data for Kuwait (1975–1982) were investigated to model the impact of ambient temperature, expressed in terms of cooling degree days (CDDs), on consumption. Linear and quadratic models were used in the analysis. It is shown that quadratic models make reasonable predictions of base monthly consumption and account for the two-fold effect of ambient temperature on consumption for cooling, i.e. its impact on the magnitude of the cooling demand and the rate of power consumption per unit of cooling output.     

Developmental transitions in the myosin heavy chain phenotype of human respiratory muscle

The renal lymphatic system plays an important role in removing excess fluid from the kidneys. Unfortunately, the factors influencing lymphatic flow are difficult to measure. We used a simple model to represent renal lymphatics as a single pressure source (PL) pushing lymph through a single resistance (RL). In anesthetized dogs, we cannulated renal lymphatics and measured lymph flow rate (QL) as we varied pressure (PO) at the outflow end of the lymphatics. There was no significant change in QL as we increased PO from -5 to 0 cm H2O. In other words, there was a plateau in the QL vs. PO relationship. At higher PO's, QL decreased linearly with increases in PO. From this linear relationship, we calculated RL as -delta PO/ delta QL and we took PL as the PO at which QL = 0 microliter/min. At baseline, RL = 0.34 +/- 0.14 (SD) cm H2O.min/microliter and PL = 8.2 +/- 4.4 cm H2O. When we increased renal venous pressure (PV) from baseline (3.5 +/- 3.0 cm H2O), the plateau in the QL vs. PO relationship extended to higher PO's, RL decreased, and PL increased. Renal interstitial fluid volume and interstitial pressure increased following elevation of PV. The extension of the QL vs. PO plateau with increasing PV suggests that renal interstitial pressure may partially collapse intrarenal collecting lymphatics which may compromise lymph flow.     

Use of a fluorescent analog of CDP-DAG in human skin fibroblasts: characterization of metabolism, distribution, and application to studies of phosphatidylinositol turnover

We studied the mechanism of action of methylene blue (Mblue), a putative guanylyl cyclase inhibitor, on the L-type calcium current (ICa) and the muscarinic activated K+ current (IK,ACh) in rat ventricular and atrial myocytes, respectively, and on the binding of [3H]quinuclidinyl benzylate in rat ventricular membranes. Superfusion, but not internal dialysis, with 30 microM Mblue antagonized the inhibitory effect of acetylcholine (ACh, 1 microM) on beta-adrenergic stimulation of ICa with isoprenaline (Iso, 10 nM or 1 microM). However, Mblue had no effect on the basal ICa or on the stimulation of ICa by Iso in the absence of ACh. The activation of IK,ACh by 3 microM ACh was also antagonized by Mblue in a dose-dependent manner. In contrast, Mblue had no effect on the activation of IK,ACh by either guanosine-5'-O-(3-thio)triphosphate or guanosine-5'-(beta,gamma-imido)triphosphate. Chlorpromazine (CPZ), a piperazine derivative like Mblue, also inhibited the muscarinic activation of IK,ACh in a dose-dependent manner. The specific binding of [3H]QNB, a muscarinic ligand, to rat ventricular membranes was displaced in a dose-dependent manner by Mblue and CPZ. The piperazine derivatives behaved like competitive antagonists of [3H]QNB binding, exhibiting equilibrium dissociation constant (Ki) values of 187 nM for Mblue and 366 nM for CPZ. In conclusion, Mblue exerts antimuscarinic effects on ICa and IK,ACh in rat cardiac myocytes that are best explained by the binding of Mblue to the M2 subtype of muscarinic receptors. This property probably contributes to the antimuscarinic effect of the putative guanylyl cyclase inhibitor reported in previous studies.     

Extraction of hiprose fruit by supercritical CO2 and propane

Extraction of whole fruit, seeds and peel of hiprose were studied with carbon dioxide, propane + carbon dioxide and propane as solvents under super- and subcritical conditions. The percentage of extract recovered from seed, whole hipfruit and hippeel was found to be 5.7–6.7, 3.0–3.5 and 0.32–0.42, respectively. The ratios of solvent to plant material, required to attain a complete extraction, were found to be 10 applying CO₂ at 35 °C and 250 bar, 3 using a solvent mixture rich in propane at 28 °C and 100 bar, and 1.1 with propane at 25 °C and 50 bar. As determined by high-performance liquid chromatographic (HPLC) methods the biologically active compounds such as carotenoids and tocopherols occur mainly in the peel of hipfruit. The oils from hip seeds increase extractability of such compounds in SF-CO₂ alone or with propane. Of the fatty acid analysed linoleic acid (C18:2) was the most abundant (52–55%) followed by linolenic acid (C18:3) which accounted for 23–24% of the total fatty acid species. No significant changes were observed in fatty acid composition of the extracts as a function of changes in the conditions of sub- and supercritical extraction.     

Drying temperature,endogenous antioxidants and capsaicinoids affect carotenoid stability in paprika (red pepper spice)

The major carotenoids and carotenoid esters in Capsicum annuum L. during thermal dehydration of pepper and storage of the ground product (paprika) were examined with special focus on the role of endogenous antioxidants such as vitamins E and C and capsaicinoids, the pungent materials in hot spice red pepper. A high‐performance liquid chromatographic (HPLC) method was developed to achieve excellent separation and accurate detection of different carotenoid classes including free xanthophylls, monoesters, carotenes and di‐esters. The newly developed method included gradient elution on a reversed‐phase column with increasing proportions of isopropanol. The results indicated that presence of capsaicinoids in pungent pepper had a favourable effect on the stability of carotenoids during thermal drying. Among various di‐esters those of lutein and zeaxanthine, as well as the mono‐ester of β‐cryptoxanthin were more stable than those of capsorubin and capsanthin, pointing to the possible role of epoxide and carbonyl groups in the susceptibility of carotenoids. An Arrhenius plot for degradation of carotenoids, tocopherols and ascorbic acid as a function of drying temperature showed linear relationships for all components, with ascorbic acid being the most sensitive. During storage in a refrigerator for 3 months the paprika showed high degradation of all the examined carotenoids particularly in samples prepared from pods dried at high temperatures (90 and 100 °C). An exception was for β‐cryptoxanthin mono‐ester and violaxanthin di‐esters in a non‐pungent variety. The amounts of these carotenoids lost during storage were slightly affected by the change in drying temperature. Strong correlation was found between retention of colour in stored paprika and the initial content of ascorbic acid, but not with that of tocopherols or capsaicinoids. Copyright © 2006 Society of Chemical Industry     

Nitrogen doping of ZnSe by OMVPE using a novel organometallic precursor

We have investigated phenylhydrazine (PhHz) as a potential nitrogen dopant source in organometallic vapor phase epitaxial growth of ZnSe. Dimethylzinc and dimethylselenide were the zinc and selenium precursors, respectively. Photoluminescence and secondary ion mass spectroscopy measurements indicate that high incorporation efficiency compared to ammonia can be achieved using this dopant source. For example, nitrogen incorporation in the 2.5 x 10¹⁸/cm^-3 level was achieved at 350°C under ultraviolet excitation when the PhHz partial pressure was 1 x 10^-8 atm. These layers had 1-2 x lO¹⁵cm^-3 electrically active acceptors. Films grown at higher partial pressures of PhHz were highly compensated.     

Effect of anesthesia and surgery on energy expenditure determined by indirect calorimetry in dogs with malignant and nonmalignant conditions

OBJECTIVE: To determine energy expenditure (EE) of apparently resting, client-owned dogs with malignant or nonmalignant diseases that were recovering from anesthesia and surgery, and compare those values with values from clinically normal, apparently resting, client owned dogs. ANIMALS: 40 apparently resting, client-owned dogs that had been given general anesthesia for various elective and nonelective surgical procedures, and 30 apparently resting, clinically normal client-owned dogs used as controls. PROCEDURE: EE was determined, using an open-flow indirect calorimetry system. Each dog was evaluated before and after surgery (0, 1, 2, and 3 days after surgery, then at suture removal > 14 days later) and compared with apparently resting, clinically normal, client-owned dogs (n = 30). Parameters evaluated were rate of oxygen consumption (Vo2/kg of body weight: ml/min/kg; Vo2/kg0.75: ml/min/kg0.75), EE (EE/kg: kcal/kg/d; EE/kg0.75: kcal/kg0.75/d), and respiratory quotient. RESULTS: Surgery and anesthesia did not significantly alter any of these parameters at any time assessed in any group. The pretreatment Vo2 and EE were significantly lower in the dogs with cancer, compared with dogs of other groups. CONCLUSIONS: These data suggest that the EE of a restricted group of dogs that undergo anesthesia and surgery for malignant and nonmalignant conditions does not increase from baseline values or when compared with values in clinically normal, client-owned dogs. CLINICAL RELEVANCE: This information may be of value when planning nutritional treatment for dogs recovering from anesthesia and surgery.     

Geometric and Group-theoretic Methods for Computer Graphic Studies of Islamic Symmetric Patterns

Over the last several years the authors have used computer graphics to generate, study and analyze more than 300 Islamic geometrical repeat patterns. These patterns offer a rich source for exploitation by artists and are also of interest to mathematicians, crystallographers, architects, archaeologists and others. They can serve as elegant test beds for research into hierarchical programming and texture mapping. The paper discusses the evolution of classical geometric methods for Islamic patterns and goes on to develop algorithms based on group theory for efficient generation of all crystallographic repeat patterns using modern computer graphics.