The hyperbolic singular value decomposition and applications

A new generalization of the singular value decomposition (SVD), the hyperbolic SVD, is advanced, and its existence is established under mild restrictions. The hyperbolic SVD accurately and efficiently finds the eigenstructure of any matrix that is expressed as the difference of two matrix outer products. Signal processing applications where this task arises include the covariance differencing algorithm for bearing estimation in sensor arrays, sliding rectangular windowing, and array calibration. Two algorithms for effecting this decomposition are detailed. One is sequential and follows a similar pattern to the sequential bidiagonal based SVD algorithm. The other is for parallel implementation and mimics Hestenes' SVD algorithm (1958). Numerical examples demonstrate that like its conventional counterpart, the hyperbolic SVD exhibits superior numerical behavior relative to explicit formation and solution of the normal equations. Furthermore, the hyperbolic SVD applies in problems where the conventional SVD cannot be employed     

Inhaled procaterol inhibits histamine-induced airflow obstruction and microvascular leakage in guinea-pig airways with allergic inflammation

BACKGROUND: Beta2-adrenoceptor agonists (beta2-agonists) are shown to inhibit airway microvascular leakage in experimental animals. This effect may change in animals with chronic airway inflammation. OBJECTIVE: We examined whether inhaled beta2-agonists inhibit microvascular leakage in guinea-pig airways with chronic allergic inflammation. METHODS: Three weeks after the sensitization with ovalbumin (OA; 6 mg/mL), each guinea pig was challenged with inhaled OA once a day for 1 or 3 weeks. Control animals without sensitization with OA also inhaled vehicle for OA (saline) for 3 weeks. One day after the last challenge, different doses of inhaled procaterol (1, 3 or 10 microg/mL) or vehicle was given to animals for 10 min after an anaesthesia. Fifteen minutes after the end of inhalation, the animals were given i.v. Evans blue dye (EB dye; 20 mg/kg), a marker of microvascular leakage, and then i.v. histamine (3 or 30 microg/kg) or vehicle. Lung resistance, a parameter of airflow obstruction, was measured for 6 min and the lungs were removed to calculate the amount of extravasated EB dye into the airways. RESULTS: A significant increase in eosinophil infiltration into the airways was seen in sensitized and challenged animals compared with control animals without sensitization. Among animals receiving antigenic exposure for either 0 (control), 1 or 3 weeks, 10 microg/mL procaterol significantly inhibited 30 microg/kg histamine-induced increase in EB dye extravasation to a similar degree (ranged from 28.7 to 69.8% inhibition) as well as that in lung resistance (more than 90% inhibition in all groups). The minimal dose of procaterol to inhibit 3 microg/kg histamine-induced microvascular leakage was not different between nonsensitized control animals and those sensitized and challenged for 3 weeks at all airway levels. CONCLUSION: Inhaled beta2-adrenoceptor agonists may be also potent in attenuating microvascular leakage even in the airways with chronic allergic inflammation.     

From pollutant to solution of wastewater pollution: Synthesis of activated carbon from textile sludge for dye adsorption

Adsorption is an important process in wastewater treatment,and conversion of waste materials to adsorbent offers a solution to high material cost related to the use of commercial activated carbon.This study investigated the adsorption behaviour of Reactive Black 5(RB5)and methylene blue(MB)onto activated carbon produced from textile sludge(TSAC).The activated carbon was synthesized through chemical activation of precursor followed with carbonization at 650°C under nitrogen flow.Effects of time(0–200 min),pH(2–10),temperature(25–60°C),initial dye concentration(0–200 mg·L~(-1)),and adsorbent dosage(0.01–0.15 g)on dye removal efficiency were investigated.Preliminary screening revealed that TSAC synthesized via H_2SO_4activation showed higher adsorption behaviour than TSAC activated by KCl and ZnCl_2.The adsorption capacity of TSAC was found to be 11.98 mg·g~(-1)(RB5)and 13.27 mg·g~(-1)(MB),and is dependent on adsorption time and initial dye concentration.The adsorption data for both dyes were well fitted to Freundlich isotherm model which explains the heterogeneous nature of TSAC surface.The dye adsorption obeyed pseudo-second order kinetic model,thus chemisorption was the controlling step.This study reveals potential of textile sludge in removal of dyes from aqueous solution,and further studies are required to establish the applicability of the synthesized adsorbent for the treatment of waste water containing toxic dyes from textile industry.     

Dietary exposure assessment of infants to bisphenol A from the use of polycarbonate baby milk bottles

The residual bisphenol A (BPA) levels in 28 different brands of polycarbonate (PC) baby milk bottles available in the Singapore market were measured. With a detection limit of 3 mg/kg, BPA residues were detected in 19 out of the 28 PC baby milk bottles at levels between 4.01 and 141 mg/kg, with a mean of 28.1 ± 31.4 mg/kg and a median of 17.2 mg/kg. The potential migration of BPA from each of the 28 PC milk bottles was also measured using food-simulating solvents and time conditions recommended by the US Food and Drug Administration (US FDA), but using temperatures more severe than actual use. The highest upper-bound mean BPA migration levels of 0.64 ± 0.48 µg/in² in 10% ethanol at 70°C and 0.43 ± 1.25 µg/in² in corn oil at 100°C were observed after incubating cut portions of the milk bottles for 240 h. With this migration data and using US FDA's procedure for estimation of dietary exposure, the worst-case dietary exposure assessment for the intake of BPA by infants between birth and three months of age was below the oral Reference Dose of 0.05 mg/kg bw/day established by the US Environmental Protection Agency. This study showed that the dietary exposure to BPA from actual uses of PC milk bottles is unlikely to pose a health risk in infants.     

The reaction of the cardiovascular system to terrain cure in patients with ischemic heart disease who have undergone surgical myocardial revascularization]

The purpose is to asses the effect of restrictive use of mediolateral episiotomy on the spontaneous laceration of the low birth canal. The material includes 613 labors some of which gave birth with indication for episiotomy and control group of 441 retrospective cases with routine management of the second period of labor. The restrictive use of episiotomy decreases the rate from 45.6% in the routine practice to 32.8%. The reduced rate of episiotomy has as a consequent increase rate of second degree perineal laceration adn insignificant increase of vaginal lacerations. The management of restrictive and liberal use of mediolateral episiotomy has not effect on third and four degree perineal laceration, on the accessory tears of the vagina and on the rate of perineotomy. If from all labors are subtracted operative deliveries, surgical intervention for repairing the laceration of the birth canal and pathology of the placental period the rate of labors without any intervention is only 13.3%. Our results suggest that labor nowadays is operative activity.     

N-glycosylation is not essential for enzyme activity of 11beta-hydroxysteroid dehydrogenase type 2

11Beta-hydroxysteroid dehydrogenase (11beta-HSD) catalyzes the oxidation of cortisol and corticosterone to cortisone and 11-dehydrocorticosterone, respectively. NAD-dependent 11beta-HSD is expressed at high levels in the distal nephron and contributes to mineralocorticoid specificity in that region. The present studies determined whether N-glycosylation is necessary for the activity of NAD-dependent 11beta-HSD (11beta-HSD2). First, cultured human colonic epithelial cells (T84 cells), which express native 11beta-HSD2 activity, were grown in medium with and without tunicamycin, an inhibitor of N-glycosylation. Tunicamycin had no effect on the enzyme activity. Next, the only putative N-glycosylation site (Asn394-Leu395-Ser396) of the cloned human kidney enzyme was eliminated by site-directed mutagenesis. Chinese hamster ovary (CHO) cells transfected with either the wild-type or the mutant cDNA construct showed no difference in the expressed enzyme activity, and Western blot analysis showed that the 11beta-HSD2 protein was the same size in cells expressing either the wild-type or the N394D mutant. Likewise, the molecular mass of the 11beta-HSD2 protein in T84 cells was not altered by treatment with peptide-N-glycosidase F or tunicamycin. We conclude that human 11beta-HSD2 is not a N-glycoprotein and N-glycosylation is not essential for the expression of enzyme activity.     

DARPP-32: regulator of the efficacy of dopaminergic neurotransmission

Dopaminergic neurons exert a major modulatory effect on the forebrain. Dopamine and adenosine 3',5'-monophosphate-regulated phosphoprotein (32 kilodaltons) (DARPP-32), which is enriched in all neurons that receive a dopaminergic input, is converted in response to dopamine into a potent protein phosphatase inhibitor. Mice generated to contain a targeted disruption of the DARPP-32 gene showed profound deficits in their molecular, electrophysiological, and behavioral responses to dopamine, drugs of abuse, and antipsychotic medication. The results show that DARPP-32 plays a central role in regulating the efficacy of dopaminergic neurotransmission.     

Peak expiratory flow in healthy Turkish children

This study was conducted on 1359 healthy, non-smoking Turkish children (727M, 632F) with a mean age of 11.7 +/- 3.4 (6-17) years, in order to determine the normal values of peak expiratory flow (PEF) in Turkish children and to compare various peak-flow meters (PEFMs). PEF values increased with age and height in boys and girls. The relative increase in boys was significantly higher at puberty (p < 0.01). The values of Turkish children were found to be similar to those of Europeans. The results obtained from the three PEFMs were closely correlated.