Bonding in cotton fiber from formaldehyde-free crosslinks

Cotton fabric was crosslinked with five agents, three of which were prepared form formaldehyde and two of which were formaldehyde-free. The formaldehyde-free agents produced less bonding between layers in the laminated microstructure of the cotton fiber. One agent, 4,5-dihydroxy-1,3-dimethyl-2-imidazolidinone, gave no evidence of any interlayer bonding. All five agents gave the same relationship between wrinkle recovery angle and molar substitution on the cotton up to moderate recovery angles, but only agents based on formaldehyde gave higher wrinkle recovery angles with additional reaction. Intralayer crosslinking did not reduce absorptivity, as shown by moisture regain and dye receptivity, but did restrict swelling in cupriethylenediamine hydroxide to the same extent as combined interlayer and intralayer crosslinking. The decrease in extensibility of treated fabric with increasing wrinkle recovery angle was the same with all agents. These results indicate the regions of the fiber that are important for each of these properties.     

DSM-IV field trials for oppositional defiant disorder and conduct disorder in children and adolescents

OBJECTIVE: The purpose of the field trials for oppositional defiant disorder and conduct disorder was to select valid diagnostic thresholds for these disorders and to compare the psychometric properties of DSM-IV criteria for oppositional defiant disorder and conduct disorder with previous DSM diagnostic formulations. METHOD: Structured diagnostic interviews, standardized clinician's validation diagnoses, and multiple measures of impairment were obtained for 440 clinic-referred children and adolescents aged 4-17 years. RESULTS: A diagnostic threshold of four symptoms of oppositional defiant disorder optimized identification of impaired children, improved agreement somewhat with the clinician's validation diagnosis, and had somewhat better test-retest agreement than DSM-III-R. In the case of conduct disorder, the optimal time window for ascertainment of symptoms was clarified. A diagnostic threshold of three symptoms of conduct disorder maximized accurate identification of impaired children and agreement with the clinician's validation diagnosis and resulted in slightly better test-retest agreement than DSM-III-R. Compared with the DSM-III-R definition, the DSM-IV definition of oppositional defiant disorder was somewhat more prevalent, but the prevalence of conduct disorder was essentially unchanged. CONCLUSIONS: DSM-IV definitions of oppositional defiant disorder and conduct disorder are somewhat better than DSM-III-R definitions in terms of internal consistency and test-retest agreement, and the validity of the DSM-IV definition of oppositional defiant disorder is slightly better than that of DSM-III-R.     

A methodology for fabrication of thermomechanically activated switchable surface wettability

In this study a platform is laid out for the creation of a multitiered surface exhibiting switchable wettability. This is done through a combination of both an acrylate‐based polymer understructure photopolymerized into a pillared array, and selectively placed surface treatments on these pillars. The acrylate‐based polymer is created through a systematic study and is shown to exhibit drastic alterations in material stiffness over a 19 °C temperature transition under aqueous conditions, allowing for stiff, erect pillars in the low temperature state, and pliable pillars that can easily be bent in the high temperature state. The glass transition temperature and onset temperature for the polymer system is found to be 49 and 30 °C, respectively. Three different surface treatments, including trichloro(1H,1H,2H,2H‐perfluorooctyl)silane, polydimethylsiloxane, and polydopamine, are investigated using static contact angle studies, and are selectively deposited onto the pillared surface such that a hydrophobic surface is exposed with the pillars erect, and a hydrophilic surface is exposed with the pillars in the bent state. The surface is shown to transition between first a hydrophobic, then hydrophilic state and return to a hydrophobic state when the investigations are coupled together forming a hierarchical surface structure. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44122.     

Student Perceptions of Asynchronous Computer-Mediated Communication in Face-to-Face Courses

While there are many distance education studies of student satisfaction or perceptions of CMC, studies on residential student perceptions of CMC are rare. A paper survey was administered to 105 residential graduate and undergraduate students at a midwestern U.S. university. Results indicated that the majority of students preferred face-to-face discussion over CMC for most tasks; however, CMC was preferred overall for simple learning tasks. Content analyses of student responses to open-ended questions revealed that some students perceived face-to-face discussion to be faster, easier, and more convenient, while others perceived that CMC saves time and is more convenient. A discriminant analysis revealed several important factors that predicted those who preferred CMC for discussion. Students further commented that they would learn better from CMC if their instructors were more involved with and enthusiastic about CMC. Speed and convenience appear to be more important to students than whether discussion is face-to-face or CMC .     

Convergence and divergence of the signaling pathways for insulin and phosphoinositolglycans

Phosphoinositolglycan molecules isolated from insulin-sensitive mammalian tissues have been demonstrated in numerous in vitro studies to exert partial insulin-mimetic activity on glucose and lipid metabolism in insulin-sensitive cells. However, their ill-defined structures, heterogeneous nature, and limited availability have prohibited the analysis of the underlying molecular mechanism. Phosphoinositolglycan-peptide (PIG-P) of defined and homogeneous structure prepared in large scale from the core glycan of a glycosyl-phosphatidylinositol-anchored membrane protein from Saccharomyces cerevisiae has recently been shown to stimulate glucose transport as well as a number of glucose-metabolizing enzymes and pathways to up to 90% (at 2 to 10 microns) of the maximal insulin effect in isolated rat adipocytes, cardiomyocytes, and diaphragms (G. Müller et al., 1997, Endocrinology 138: 3459-3476). Consequently, we used this PIG-P for the present study in which we compare its intracellular signaling with that of insulin. The activation of glucose transport by both PIG-P and insulin in isolated rat adipocytes and diaphragms was found to require stimulation of phosphatidylinositol (PI) 3-kinase but to be independent of functional p70S6kinase and mitogen-activated protein kinase. The increase in glycerol-3-phosphate acyltransferase activity in rat adipocytes in response to PIG-P and insulin was dependent on both PI 3-kinase and p70S6kinase. This suggest that the signaling pathways for PIG-P and insulin to glucose transport and metabolism converage at the level of PI 3-kinase. A component of the PIG-P signaling pathway located up-stream of PI 3-kinase was identified by desensitization of isolated rat adipocytes for PIG-P action by combined treatment with trypsin and NaCl under conditions that preserved cell viability and the insulin-mimetic activity of sodium vanadate but completely blunted the insulin response. Incubation of the cells with either trypsin or NaCl alone was ineffective. The desensitized adipocytes were reconstituted for stimulation of lipogenesis by PIG-P by addition of the concentrated trypsin/salt extract. The reconstituted adipocytes exhibited 65-75% of the maximal PIG-P response and similar EC50 values for PIG-P (2 to 5 microns) compared with control cells. A proteinaceous N-ethylmaleimide (NEM)-sensitive component contained in the trypsin/salt extract was demonstrated to bind in a functional manner to the adipocyte plasma membrane of desensitized adipocytes via bipolar interactions. An excess of trypsin/salt extract inhibited PIG-P action in untreated adipocytes in a competitive fashion compatible with a receptor function for PIG-P of this protein. The presence of the putative PIG-P receptor protein in detergent-insoluble complexes prepared from isolated rat adipocytes suggests that caveolae/detergent-insoluble complexes of the plasma membrane may play a role in insulin-mimetic signaling by PIG-P. Furthermore, treatment of isolated rat diaphragms and adipocytes with PIG-P as well as with other agents exerting partially insulin-mimetic activity, such as PI-specific phospholipase C (PLC) and the sulfonylurea glimepiride, triggered tyrosine phosphorylation of the caveolar marker protein caveolin, which was apparently correlated with stimulation of lipogenesis. Strikingly, in adipocytes subjected to combined trypsin/salt treatment, PIG-P, PI-specific PLC, and glimepiride failed completely to provoke insulin-mimetic effects. A working model is presented for a signaling pathway in insulin-sensitive cells used by PIG(-P) molecules which involves GPI structures, the trypsin/salt- and NEM-sensitive receptor protein for PIG-P, and additional proteins located in caveolae/detergent-insoluble complexes.     

Absorption phenomena in the treatment of cotton with formaldehyde and cyclic oxymethylenes

Monomeric formaldehyde and the cyclic oxymethylenes tetraoxane and pentaoxane were retained by cotton to similar extents at the high temperatures used in textile finishing, but the mechanisms of absorption appeared to differ. Trioxane, however, was not retained by cotton. The absorption of cyclic oxymethylenes did not seem to involve bonding to cellulose by primary valence bonds. The presence of other substances had a greater effect on the absorption of monomeric formaldehyde than of cyclic oxymethylenes, but changes in extent of absorption were not large enough to influence textile properties of treated fabric.     

CMOS Microsystem Front-End for MicroTesla Resolution Magnetic Field Measurement

In this paper we discuss the conception and performances of a monolithic microsystem for magnetic field measurement built in standard 0.6 m CMOS technology. It is shown that 5.2 microTesla resolution over 1 kHz bandwidth (5 Hz to 1 kHz) can be achieved by combining a particular Hall effect based sensing device and appropriate analog conditioning electronics. The study focuses on the methods used to drive up the sensor's sensitivity and to drive down the system's noise level in order to achieve the above-mentioned resolution. A specific circuitry is proposed for biasing the sensor.