How children and adolescents spend time across the world: Work, play, and developmental opportunities.

The authors review studies on time use of children and adolescents around the world and discuss developmental implications of population differences. Industrialization and schooling are linked to dramatic declines in time spent on household and wage labor. This labor is often unchallenging, sometimes hazardous; developmental benefits often do not increase above a limited number of hours; hence, reduction in these activities opens time for activities that may be more developmentally beneficial. Adolescents in East Asian postindustrial societies spend this freed-up time in schoolwork, a use associated with lower intrinsic motivation but high achievement and economic productivity. Adolescents in North America spend more time in leisure, associated with greater self-direction but of an uncertain relation to development. Age, gender, and socioeconomic differences in activities and with whom time is spent are also considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

TecoflexTM functionalization by curdlan and its effect on protein adsorption and bacterial and tissue cell adhesion

Curdlan modified polyurethane was created by physically entrapping the former on TecoflexTM surface. ATR-FT-IR, SEM-EDAX and AFM analysis revealed the formation of stable thin curdlan layer on the film. Contact-angle measurements showed that the modified film was highly hydrophilic. Confocal laser scanning microscopy showed the existence of entrapped layer of approximately 20–25 μm in depth. Surface entrapment of curdlan minimized both protein adsorption and mouse L929 fibroblast cell adhesion relative to the control. Surface induced cellular inflammatory response was determined from the expression levels of proinflammatory cytokine TNF-α, by measuring their mRNA profiles in the cells using real time polymerase chain reaction (RT-PCR) normalized to the housekeeping gene GAPDH. The inflammatory response was suppressed on the modified substrate as expression of TNF-α mRNA was found to be up regulated on TecoflexTM, while it was significantly lower on curdlan substrate. The adhesion of S. aureus decreased by 62% on curdlan modified surface. Using such simple surface entrapment process, it will be possible to develop well-defined surface modifications that promote specific cell interactions and perhaps better performance in the long-term as implant.     

Brain targeted delivery of anticancer drugs: prospective approach using solid lipid nanoparticles

A brain tumour is amongst most devastating and challenging condition to overcome with suitable treatment as the drug has to cross the blood–brain barrier (BBB) with several physiological barriers like opsonisation by the reticuloendothelial system. Presently various techniques such as surgical, chemotherapeutic agents, and radiotherapy techniques have performed to extend the lifespan of patients diagnosed with glioblastoma, which did not maximise the overall survival of patients with a tumour. Nanotechnology is relied upon to diminish the requirement for intrusive methods for conveyance of therapeutics to the central nervous system. Colloidal nanocarriers sizing range 1–1000 nm have been utilised to cross BBB delivers the drug at cell levels with enhanced bioavailability and reduced toxicity. However, solid lipid nanoparticles (SLNs) are considered a highly flexible carrier for more successful remedially in brain tumour. The treatment of a brain tumour via SLNs is gaining greater potency due to its inimitable size and lipidic nature. This review focuses and represents the current strategies of SLNs in the brain tumour treatment with appropriate techniques adopted are highlighted. Based on this review, the authors concluded that SLNs embrace exclusive promising lipidic nanocarrier that could be utilised to target a brain tumour effectively.Inspec keywords: brain, cancer, nanoparticles, blood, molecular biophysics, tumours, nanomedicine, neurophysiology, radiation therapy, colloids, biomedical materials, drug delivery systems, nanofabrication, drugs, cellular biophysicsOther keywords: chemotherapeutic agents, radiotherapy techniques, central nervous system, colloidal nanocarriers sizing range 1–1000 nm, BBB, drug, solid lipid nanoparticles, brain tumour therapeutical uses, lipidic nature, brain tumour treatment, brain targeted delivery, anticancer drugs, prospective approach, blood–brain barrier, physiological barriers, reticuloendothelial system, surgical agents, lipidic nanocarrier, size 1.0 nm to 1000.0 nm     

Tri-axial recording of event-related potentials during passive cognitive tasks in patients with Alzheimer''s disease

A novel dynamic mathematical microelectrode model (a model of solvent and solute kinetics in electrolyte-filled microelectrodes) was deduced from experimental observations made on standard (single-barrelled, 3.0 M KCl-filled, approximately 10 M[ohm]) electrodes using (a) electrodiffusion, electro-osmosis, and continuity equations that were placed into the constraints of electrode geometry, and (b) handbook/textbook parameter values, only. The model proved to be able to faithfully reproduce all observed electrochemical and electrical electrode properties, i.e. even those that constituted no part of the model's experimental basis. In theoretical tests, the model shows, for the standard electrode that (a) inside the electrode, any profiles in electrical potential and electrolyte concentration are occurring at the most distal part (approximately 50 microm) of the tip region, (b) asymmetrical shifts in electrolyte concentration just inside the electrode tip opening are the true cause of the electrode's current rectification, and (c) strong transelectrode currents are producing water flows across the electrode orifice that may affect the volume of smaller and medium-sized cells. In further tests, the model shows, among other things, for non-standard electrodes that (a) decreasing the electrode electrolyte concentration will give rise to marked decreases in electrolyte leakage from the electrode, but only very minor changes in tip potential, and (b) increasing the surface charge of the electrode glass (increases in zeta potential) and/or decreasing the electrode electrolyte concentration will produce increases in electro-osmotic water transport, which may be desirable for the intracellular injection of water-soluble (electro-neutral) substances.     

Laboratory-Based Productivity Study on Alternative Masonry Systems

Masonry construction over the last century has undergone radical changes that have led to specific improvements in construction performance due to the advent of large-sized blocks, innovative methods like surface-bonded masonry, partially grouted masonry, and dry-stacked/mortarless masonry using interlocking blocks. This paper outlines relative productivity assessment of conventional and interlocking-block masonry with different construction methods. To measure the utilization of time by the members of the team, work sampling (adopting the 5 min rating technique) was used. The frequencies of occurrences of each work category, namely direct, indirect, and noncontributory, have been established. Due to the variation in the noncontributory work component for different methods of construction, the net output has been expressed as output per productive hour. Productivity enhancement of 80–120% was observed for dry-stacked masonry and 60–90% more for thin-jointed and mortar-bedded interlocking-block masonry than that of conventional masonry.     

Histologic spectrum of arterial and arteriolar lesions in acute and chronic cocaine-induced mesenteric ischemia: report of three cases and literature review

Gastrointestinal complications of cocaine abuse occur less frequently than those of the cardiovascular and nervous systems. The clinical history and pathologic findings of three patients with cocaine-induced mesenteric ischemia are described, and the mechanism of acute and chronic cocaine-induced mesenteric ischemia is discussed. The role of preoperative angiography in detecting occlusive arterial lesions so that arterial revascularization can be carried out is emphasized. Briefly, recent intravenous cocaine use in a 45-year-old man resulted in sharply demarcated small intestinal ischemia with perforation characterized by pseudomembranous enteritis. Histologic sections of the small-bowel resection showed intraluminal fibrin and intimal hyperplasia in rare submucosal arterioles. Two women, 29 and 35 years of age, both with a 2-year history of intravenous cocaine use, presented with acute abdominal pain and had angiographic documentation of occlusion of the celiac axis and the superior mesenteric arteries. Vascular bypasses were performed in both cases. Microscopic examination of both arteries and their branches revealed total obstruction by luminal thrombus with recanalization.     

Microstructural characterization of electron beam-physical vapor deposition thermal barrier coatings through high-resolution computed microtomography

Thermal barrier coatings (TBCs), deposited using the electron beam-physical vapor deposition (EB-PVD) process, comprise a unique architecture of porosity capable of bridging the technological gap between insulation/life extension and prime reliance. The TBC microstructures consist of columnar structure, nucleated via vapor condensation, along with a high degree of intercolumnar porosity, thus providing enhanced stress relief on thermomechanical loading and also accommodating misfit stresses resulting from CTE mismatch. In this article, we report the characterization of these coatings using high-resolution synchrotron-based X-ray computed microtomography (XMT) at 1.3-μm resolution. Experiments focused on quantitative characterization/visualization of imperfections in these coatings and on the relative changes in microstructural features upon isothermal annealing. The influence of time/temperature of exposure was investigated and the results were correlated with elastic modulus. This article is based on a presentation made at the symposium “Characterization and Representation of Material Microstructures in 3-D” held October 8–10, 2002, in Columbus, OH, under the auspices of ASM International’s Phase Transformations committee.     

Combined neck dissection and postoperative radiation therapy in the management of the high-risk neck: a matched-pair analysis

PURPOSE: Our purpose was to determine the sensitivity, specificity, and receiver operator characteristic (ROC) curve of a fast screening MR protocol in children and adolescents with suspected intracranial tumors. METHODS: One hundred forty-one patients (mean age, 9.7 years; range, 2 months to 23.5 years) with suspected brain tumor were entered in a case-control study. Eighty-seven patients had intracranial tumors (31 suprasellar/hypothalamic, 27 supratentorial, 26 infratentorial, and three pineal) and 54 patients in the control group had other disorders. Two neuroradiologists reviewed blindly a detailed three-sequence conventional protocol (acquisition time, 8 minutes 27 seconds) and a two-sequence fast screening MR protocol (acquisition time, 4 minutes 44 seconds). RESULTS: Sensitivity and specificity of the fast screening protocol for intracranial tumors was 100% and 92.6%, respectively. The areas under the ROC curves were 0.966 for the fast screening and 0.980 for the conventional MR protocol. No diagnostic performance difference was found between the ROC curves using the Az index. A kappa statistic of .93 for both examinations indicated excellent interobserver agreement. Additional MR sequences and other neuroimaging studies were not deemed necessary to exclude the presence of an intracranial tumor. CONCLUSION: A fast dual-plane brain MR protocol may be adequate to screen children and adolescents thought to have an intracranial tumor. The less than 5 minute acquisition time allows a complete examination (including preparation) to be performed in 10 to 15 minutes. Future studies are recommended before this time-efficient neuroimaging examination is incorporated into clinical practice.     

Miscibility,crystallization and annealing studies of poly(vinylidene fluoride)/hyperbranched polyester blends

In this study, miscibility and crystallization behavior of polyvinylidene fluoride (PVDF) and its blends with hyperbranched polyester (HBPE, 0 to 50 wt.-% of HBPE in PVDF) are investigated by means of DSC and FTIR techniques. Among the varying blend compositions, PVDF/HBPE (100/0 and 90/10) blend ultrathin film samples were subjected to thermal annealing at different temperatures (30–200 °C) in order to examine and compare their crystallization behavior. From FTIR data, the all-trans band (A₁) at ca. 1280 cm⁻¹ corresponding to the changes in ferroelectric β-crystalline phase for both the samples exhibits higher absorption intensity upon annealing at 90 °C, well below their melting temperature range (T_m∼160 °C), whereas, the sample melt-annealed at 210 °C exhibit reduced A₁ absorption intensity, which is attributed to the crystalline transformation from ordered ferroelectric phase into the disordered amorphous phase. Quantitative data from Factor analysis revealed the existence of higher ferroelectric β-crystalline phase content in PVDF/HBPE (90/10) blend ultrathin film sample than in commercially available PVDF and PVDF/TrFE (72/28) ultrathin film samples, which exemplifies the importance of this study. The enhanced ferroelectric characteristics exhibited by the PVDF/HBPE (90/10) blend ultrathin film samples can be well-suited for electronic applications such as non-volatile memory devices, sensors, etc.