Nocturnal enuresis in children]

After allergic disorders, nocturnal enuresis is the most common chronic childhood condition. Recent research has yielded abundant new knowledge about the condition, especially about its aetiology and pathophysiology, and the psychological consequences. A hereditary background has been substantiated by the identification in genetic linkage studies of areas in chromosomes 12 and 13 that are manifestly associated with bedwetting, though genotype expression in the phenotype appears to be complex and heterogeneous. Pathophysiologically, findings in current intensive research suggest three interactive factors to be involved: (i) relative nocturnal polyuria, due to insufficient antidiuretic hormone release during sleep in pre-teenagers, and due to renal tubular dysfunction in adolescents and adults; (ii) reduced nocturnal bladder capacity, especially in the 33 per cent of cases which do not respond to desmopressin treatment; and (iii) the patient's inability to waken in response to signals from a full bladder. Recent findings have also confirmed previous reports that with very few exceptions bedwetting is not caused by psychological factors. On the contrary, the condition causes psychological problems manifested in reduced self-esteem, shame and guilt, though self-esteem is restored by successful treatment. Active treatment should be started as soon as the child is ready to receive it, the main options being an enuresis alarm, desmopressin, or a combination of the two. If reduced bladder capacity is suspected, treatment with a detrusor relaxant should be included.     

Turn-taking patterns in human discourse and their impact on group communication service design

Recent studies demonstrated the benefit of integrating speaker prediction features into the design of group-communication services supporting multiparty online discourse. This paper aims at delivering a more elaborate analysis of speaker prediction by analyzing a larger volume of data. Moreover, it tests the existence of speakers dominating speaking time. Towards this end, we analyze tens of hours of recorded meeting and lecture sessions. Our principal results for meeting-like interaction manifest that the next speaker is one of the last four speakers with over 90% probability. This is seen consistently across our data with little variance (standard deviation of 8.71%) independent of the total number of potential speakers. Furthermore, lecture time is in most cases significantly dominated by the tutor. In meetings, although a single dominating speaker is always evident, domination exhibited high variability. Generally, our findings strengthen and further motivate the act of incorporating user-beha vior awareness into group communication service design.     

Site‐Selective Deposition of Nanostructured ZnO Thin Films from Solutions Containing Polyvinylpyrrolidone

When soluble zinc salts are hydrolyzed in water, usually elongated micrometer‐sized zincite crystals are formed. In this study, polyvinylpyrrolidone (PVP) in a methanolic solution is used as an agent to control the morphology of the deposition product. It prevents crystal growth and yields zinc oxide nanocrystals. Thin films consisting of zinc oxide nanocrystals are formed on self‐assembled monolayers (SAMs) of sulfonate‐terminated alkylsiloxanes. Patterned films are deposited after local decomposition of the SAM by UV irradiation. The films fabricated from methanolic solutions containing PVP are particularly smooth, uniform and stable. Their thickness is determined by the deposition time and the molar ratio [PVP]:[Zn²⁺], so that films of arbitrary thickness and nearly constant roughness can be obtained. The crystal grains are oriented preferentially with 〈001〉 direction perpendicular to the substrate surface. The films show ultraviolet, orange‐red and green‐yellow photoluminescence; the latter is quenched by heat treatment. Based on the obtained experimental results, a deposition mechanism is suggested.     

Adhesion-Induced Phase Behavior of Two-Component Membranes and Vesicles

The interplay of adhesion and phase separation is studied theoretically for two-component membranes that can phase separate into two fluid phases such as liquid-ordered and liquid-disordered phases. Many adhesion geometries provide two different environments for these membranes and then partition the membranes into two segments that differ in their composition. Examples are provided by adhering vesicles, by hole- or pore-spanning membranes, and by membranes supported by chemically patterned surfaces. Generalizing a lattice model for binary mixtures to these adhesion geometries, we show that the phase behavior of the adhering membranes depends, apart from composition and temperature, on two additional parameters, the area fraction of one membrane segment and the affinity contrast between the two segments. For the generic case of non-vanishing affinity contrast, the adhering membranes undergo two distinct phase transitions and the phase diagrams in the composition/temperature plane have a generic topology that consists of two two-phase coexistence regions separated by an intermediate one-phase region. As a consequence, phase separation and domain formation is predicted to occur separately in each of the two membrane segments but not in both segments simultaneously. Furthermore, adhesion is also predicted to suppress the phase separation process for certain regions of the phase diagrams. These generic features of the adhesion-induced phase behavior are accessible to experiment.     

Synthesis of 4-chlorophenoxyacetate-zinc-aluminium-layered double hydroxide nanocomposite: physico-chemical and controlled release properties

Layered organic-inorganic hybrid nanocomposite material was synthesised using 4-chlorophenoxyacetate (4CPA) as guest anion intercalated into the Zn-Al layered double hydroxide inorganic host by direct co-precipitation method at pH = 7.5 and Zn to Al molar ratio of 4. Both PXRD and FTIR results confirmed that the 4CPA was successfully intercalated into the Zn-AI-LDH interlayer. As a result, a well-ordered nanolayered organic-inorganic hybrid nanocomposite, with the expansion of the basal spacing from 8.9 angstroms in the layered double hydroxide to 20.1 angstroms in the resulting nanocomposite was observed. The FTIR spectrum of the nanocomposite (ZAC) showed that it composed spectral features of Zn-AI-LDH (ZAL) and 4CPA. The nanocomposites synthesized in this work are of mesoporous-type containing 39.8% (w/w) of 4CPA with mole fraction of Al3+ in the inorganic brucite-like layers (xAI) of 0.224. The release studies showed a rapid release of the 4CPA for the first 600 min, and more sustained thereafter. The total amount of 4CPA released from the nanocomposite interlayer into the aqueous solution were 21%, 66%, and 72% in 0.0001, 0.00025, and 0.0005 M sodium carbonate, respectively. In distilled water, about 75, 35, and 57% of 4CPA could be released in 1000 min, when the pH of the release media was set at 3, 6.25, and 12, respectively. In comparison with a structurally similar organic moiety with one more chlorine atom at the 2-position of the aromatic ring, namely 2,4-dichlorophenoxyacetate (24D), the 4CPA showed a slower release rate. The slightly bulkier organic moiety of 24D together with the presence of chlorine atom at the 2-position presumably had contributed to its higher release rate, and it seems that these factors may be exploited for tuning the release rate of intercalated guest anions with similar properties. This study suggests that layered double hydroxide can be used as a carrier for an active agent and the chemical structure of the intercalated moiety can be used to tune the desired release kinetics of the beneficial agent.     

Synthesis and characterization of low cost willemite based glass–ceramic for opto-electronic applications

This paper presents a comprehensive study on thermal, structural and optical properties of novel willemite glass–ceramics. The precursor glass in the ZnO–SLS glass system was successfully prepared using conventional melt-quenching technique and willemite (Zn₂SiO₄) glass–ceramics were derived from this precursor glass by a control crystallization process. The effect of heat-treatment temperature on the phase transformation, morphology and size of Zn₂SiO₄ crystal phase was examined using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) techniques. Furthermore, fourier transform infrared reflection (FTIR) spectroscopy was used to evaluate the Zn₂SiO₄ crystal structural evolution. The average size of Zn₂SiO₄ crystallite obtained from calculation of XRD is found to be in the range 30–60 nm, whereas the grain size observed in FESEM is in range of 200–400 nm. The appearance of SiO₂, ZnO₄ and Zn–O–Si bands detected from FTIR indicate the formation of Zn₂SiO₄ crystal phase. Besides, the study of the optical band gap has found that optical band gap of the glass–ceramics decreased as the heat treatment temperature increased. The photoluminescence spectra of willemite glass–ceramics exhibit two different emissions around 525 nm (green) and 585 nm (yellow); exhibit a characteristic of broad absorption band around 260 nm. These two different spectra reveal that the luminescence performance of the willemite glass–ceramics was enhanced with the progression of heat treatment temperature due to different located energy levels of the β-Zn₂SiO₄ and α-Zn₂SiO₄ crystalline phase. Such luminescent glass–ceramics was expected to find potential applications in phosphors and opto-electronic devices.     

Indentation testing of nuclear-waste glasses

The fracture properties of several nuclear-waste glasses were determined by indentation techniques. The fracture toughness,K _Ic, was calculated from the measurement of radial cracks around Vickers diamond indentations as a function of applied load, and the results agree quite satisfactorily with values obtained by the Hertzian indentation technique. The fracture toughness of the waste glasses containing simulated fission products ranged from 0.9 to 1.1 MN m^–3/2 in air, with slightly higher values measured in dry nitrogen. The hardness was also obtained from the Vickers indentations and the ratioH/E was determined from the elastic recovery of Knoop diamond indentations. The values ofE deduced fromH andH/E were within 15% of values measured by ultrasonic tests. The results along with the limitations of the different techniques are discussed in detail.Supported by the US Department of Energy.