Asthma and pregnancy

Pregnancy is accompanied by physiological hyperventilation that may be perceived as shortness of breath; causes are a reduced residual capacity and a reduced expiratory reserve volume due to the swelling uterus, and a larger tidal volume due to increase of the progesterone concentration and of the chemosensitivity to CO2 and O2. Fatigue, lowered exercise tolerance and orthopnoea also may occur, as do basal crepitations at auscultation. In pregnant asthma patients the symptoms may either improve greatly or become aggravated. During an asthma attack the foetus is exposed to hypoxaemia, which may be worsened by a decreased uteroplacental blood circulation in case of maternal alkalosis. Poorly controlled asthma has a stronger adverse effect on the unborn child than the judicious use of anti-asthma drugs. Safe drugs against asthma during pregnancy, around parturition and during breast feeding, are cromoglycic acid and ipratropium; relatively safe drugs are short-acting beta-sympathicomimetics, inhalation corticosteroids and systemic corticosteroids, as well as theophylline from the second trimester; use of long-acting beta-sympathicomimetics is advised against.     

Galvanic skin response and reported anxiety during systematic desensitization.

Preselected 3 groups of 8 females each for high snake fear. 1 group received systematic desensitization with relaxation, another desensitization without relaxation (essentially exposure to phobic visualizations), and the 3rd relaxation and visualization of neutral scenes. Outcome measures indicate that the desensitization group reduced phobic behavior most, followed by the relaxation group, and then the exposure group. Total amplitude of GSR responsivity during a visualization showed a more rapid habituation for the desensitization group than either exposure or relaxation group. Results confirm the initial hypotheses and provide support for a counterconditioning explanation of systematic desensitization with relaxation as the mediator or counterconditioner. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Endogenous skin fluorescence includes bands that may serve as quantitative markers of aging and photoaging

Aging and photoaging cause distinct changes in skin cells and extracellular matrix. Changes in hairless mouse skin as a function of age and chronic UVB exposure were investigated by fluorescence excitation spectroscopy. Fluorescence excitation spectra were measured in vivo, on heat-separated epidermis and dermis, and on extracts of mouse skin to characterize the absorption spectra of the emitting chromophores. Fluorescence excitation spectra obtained in vivo on 6 wk old mouse skin had maxima at 295, 340, and 360 nm; the 295 nm band was the dominant band. Using heat separated tissue, the 295 nm band predominantly originated in the epidermis and the bands at 340 and 360 nm originated in the dermis. The 295 nm band was assigned to tryptophan fluorescence, the 340 nm band to pepsin digestable collagen cross-links fluorescence and the 360 nm band to collagenase digestable collagen cross-links fluorescence. Fluorescence excitation maxima remained unchanged in chronologically aged mice (34-38 wk old), whereas the 295 nm band decreased in intensity with age and the 340 nm band increased in intensity with age. In contrast, fluorescence excitation spectra of chronically UVB exposed mice showed a large increase in the 295 nm band compared with age-matched controls and the bands at 340 and 350 nm were no longer distinct. Two new bands appeared in the chronically exposed mice at 270 nm and at 305 nm. These reproducible changes in skin autofluorescence suggest that aging causes predictable alterations in both epidermal and dermal fluorescence, whereas chronic UV exposure induces the appearance of new fluorphores.     

Children's perception of nasal resonance

The purpose of this study was to investigate children's perception of nasal resonance in other children. A total of 120 elementary-school-aged children listened to four female children's voices with normal resonance to severe hypernasality and responded to a total of 20 questions. All children responded negatively to severe hypernasality in other children. The findings indicate that hypernasality warrants correction.     

Stimulated Raman scattering of XeF* laser radiation in H2

Stimulated Raman scattering (SRS) experiments have been performed using an ∼2 J,sim0.4 mus pulsewidth XeF* laser as the pump and high-pressure molecular hydrogen as the Raman-active medium. The SRS conversion efficiency and spectral distribution have been characterized as functions of H2pressure and pump laser focal parameters. Energy conversion efficiencies of >60 percent have been obtained, with the converted energy in first and second Stokes radiation, at 414 nm and 500 nm, respectively.     

Mothers’ and fathers’ attributions for adolescent behavior: An examination in families of depressed, subdiagnostic, and nondepressed youth.

This study examined whether parents of adolescents experiencing depressive symptoms or disorder make more negative and fewer positive attributions for their adolescents’ behavior than do parents of nondepressed adolescents, and whether parental attributions for adolescents’ behavior contribute to parenting behavior, above and beyond the adolescents’ behavior. Parents and adolescents (76 girls and 48 boys) participated in videotaped problem-solving interactions (PSIs). Each parent subsequently watched the videotape and offered attributions for their adolescent’s behavior. In addition, parent and adolescent behavior during the PSIs was coded. Mothers and fathers in families of nondepressed adolescents made significantly fewer negative attributions for their children’s behavior than did parents in families of adolescents with diagnostic or subdiagnostic levels of depressive symptoms. Moreover, mothers’ and fathers’ negative attributions were related to greater levels of observed aggressive behavior and lower levels of observed facilitative behavior during the PSIs controlling for both demographic characteristics and the relative level of adolescent aggressive and facilitative behavior during the PSI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contact physics of gold microcontacts for MEMS switches

This work presents a study of gold metallic contacts regarding contact resistance, heat dissipation, and surface damage in the normal-force regime of tens to hundreds of μN, which is typical of the contact forces from microactuation. The purpose of this work is to present the micromechanical switch designer with practical information on gold contact phenomena in this force regime, as most work in micrometallic contacts has focused on contact forces greater than 1 mN. Results indicate actuation forces of several hundred μN are required for reliable fully metallic contacts, with resistance and current carrying ability primarily dependent on morphology, thermal management, and nm-depth material properties of the contact electrodes     

Electrosynthesis and characterization of new conducting copolymer films from 1‐naphthol and methyl naphthyl ether

New conducting polymer films have been prepared on platinum electrodes by anodic polymerization of 1‐naphthol in the presence of methyl naphthyl ether (MNE) in MeCN containing 0.1 M LiClO₄. The presence of MNE was found to suppress oligomer formation and significantly affect the physicochemical properties of the polymeric films formed via copolymerization, as confirmed by IR and elemental analysis. In contrast to the autocatalytic polymerization mechanism observed during poly(1‐naphthol) formation, a competitive catalytic‐inhibiting mechanism was found for the copolymer. The copolymer (1:1 and 1:10 1‐naphthol:MNE) showed electrochemical activity similar to that of poly(1‐naphthol). The copolymer films resisted degradation in MeCN effectively and charging–discharging cycles led to doubling of the redox charge after about 20 cycles, while poly(1‐naphthol) films lost 90% of the redox charge under the same conditions. The conductivity of copolymer (1:1) films were 1–2 orders of magnitude lower than that of poly(1‐naphthol). The diffusion coefficients of the charge transfer for the doping–dedoping processes of the copolymer films were slightly lower than for poly(1‐naphthol), but the diffusion coefficients for the redox [Fe(CN)₆]^3−/4− were comparable for both films. © 2000 Society of Chemical Industry