The synthesis of monomers with pendent ethynyl group for modified high performance thermoplastics

The objectives of this project were to develop synthetic schemes for the following classes of modified monomers: (1) difunctional triarylethanes with pendent acetylenic groups; and (2) tertiary aspartimides with terminal acetylene groups at the two ends. Our efforts have resulted in the successful development of high yield schemes for the syntheses of several diamino and bisphenolic analogs of difunctional triarylethanes with pendent ethynyl group. A scheme for one new tertiary aspartimide was also established. Multi-gram samples of all prepared new monomers were provided to our technical contact at NASA-LaRC and preliminary polymerization studies were encouraging. Details of the accomplished work within the last four years are described

Coping Strategies of Jordanian Adolescents With Cancer: An Interpretive Phenomenological Analysis Study

Interpretive phenomenological analysis methodology was used to explore coping strategies used by hospitalized Jordanian adolescents with cancer. In-depth face-to-face interviews were conducted with 10 Jordanian adolescents, aged 13 to18 years, who were receiving chemotherapy for cancer. During treatment, participants were confronted with physical, psychosocial, and emotional distresses resulting from the disease process, the treatment, and its associated side-effects. To cope with the impact of their illness, participants utilized 4 coping strategies: "Strengthening spiritual convictions," "Being optimistic and rebuilding hope," "Enhancing appearance," and "Finding self again." The findings of this study can assist health team members to promote positive psychological care to Arab Muslim adolescents with cancer in a supportive and therapeutic treatment environment

Nonlinear control and active damping of a forced-feedback metering poppet valve

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file (viewed on January 31, 2008)Vita.Thesis (Ph. D.) University of Missouri-Columbia 2007.For a metering poppet valve which was developed at the University of Missouri (MU valve), the valve can be configured for performance at the cost of stability. It is desirable to achieve both performance and stability using electronic control. Presently, in the MU valve, the pilot poppet motion is damped by the flow of hydraulic fluid through a channel or orifice running through the poppet. In this research, it is proposed that the solenoid be used to provide damping (active damping) to the pilot poppet. The damping input signal to the solenoid is determined as a function of the pilot poppet velocity. In practice, the velocity is difficult to measure due to the MU valve's configuration and it is estimated according to the self-sensing actuator concept. Theoretical results demonstrated that a valve actuator could be designed with an emphasis on high speed performance while an electronic control system is used to damp unwanted oscillations. For flow control, several researchers have used feedback linearization to cancel part of a hydraulic system's nonlinearities in spool valves. In the case of the metering poppet valve, feedback linearization is an attractive approach since experimental studies have shown that poppet instabilities are caused by nonlinear mechanisms like flow forces. In this work, nonlinearities are cancelled in the input-output relationship of the metering poppet valve. The controller was shown to achieve robust tracking of a reference trajectory.Includes bibliographical reference

The synthesis of monomers with pendent ethynyl groups for modified high performance thermoplastics

Synthetic schemes were developed and optimized for twelve new monomers possessing unique structural features and one aspartimide. Two synthetic pathways were compared for preparation of the triarylethane monomers with pendent ethynyl groups. The results show that one of these pathways can be generally applied. The alternative pathway was applicable to the preparation of only one of the twelve compounds, the problem being secondary reactions of the initially formed desired product

Oesophageal pressure-flow metrics in relation to bolus volume, bolus consistency and bolus perception

Author version made available in accordance with the publisher's policy.The utility of combined oesophageal pressure–impedance recording has been enhanced by automation of data analysis. To understand how oesophageal function as measured by automated impedance manometry (AIM) pressure-flow analysis varies with bolus characteristics and subjective perception of bolus passage. Oesophageal pressure–impedance recordings of 5 and 10 ml liquid or viscous swallows and 2 and 4 cm solid swallows from 20 healthy control subjects (five male; 25–73 years) were analysed. Metrics indicative of bolus pressurization (intrabolus pressure and intrabolus pressure slope) were derived. Bolus flow resistance, the relationship between bolus pressurization and flow timing, was assessed using a pressure-flow index. Bolus retention was assessed using the ratio of nadir impedance to peak pressure impedance (impedance ratio). Subjective perception of bolus passage was assessed swallow by swallow. Viscosity increased the bolus flow resistance and reduced bolus clearance. Responses to boluses of larger volume and more viscous consistency revealed a positive correlation between bolus pressurization and oesophageal peak pressure. Flow resistance was higher in subjects who perceived bolus hold up of solids. Bolus volume and bolus type alter oesophageal function and impact AIM analysis metrics descriptive of oesophageal function. Perception of bolus transit was associated with heightened bolus pressurization relative to bolus flow

Whey- vs Casein-Based Enteral Formula and Gastrointestinal Function in Children With Cerebral Palsy.

Objectives: Children with severe cerebral palsy (CP) commonly have gastrointestinal (GI) dysfunction. Whey-based enteral formulas have been postulated to reduce gastroesophageal reflux (GOR) and accelerate gastric emptying (GE). The authors investigated whether whey-based (vs casein-based) enteral formulas reduce GOR and accelerate GE in children who have severe CP with a gastrostomy and fundoplication. Methods: Thirteen children received a casein-based formula for 1 week and either a 50% whey whole protein (50% WWP) or a 100% whey partially hydrolyzed protein (100% WPHP) formula for 1 week. Reflux episodes, gastric half-emptying time (GE t1/2), and reported pain and GI symptoms were measured. Results: Whey formulas emptied significantly faster than casein (median [interquartile range (IQR)] GE t1/2, 33.9 [25.3-166.2] min vs 56.6 [46-191] min; P = .033). Reflux parameters were unchanged. GI symptoms were lower in children who received 50% WWP (visual analog symptom score, median [IQR], 0[0-11.8]) vs 100% WPHP (13.0 [2.5-24.8]) (P = .035). Conclusion: This pilot study shows that in children who have severe CP with a gastrostomy and fundoplication, GE of the whey-based enteral formula is significantly faster than casein. The acceleration in GE does not alter GOR frequency, and there appears to be no effect of whey vs casein in reducing acid, nonacid, and total reflux episodes. The results indicate that enteral formula selection may be particularly important for children with severe CP and delayed GE. (JPEN J Parenter Enteral Nutr. 2012;36:118S-123S

GROWTH OF SILICON BY LIQUID PHASE EPITAXY AT LOW TEMPERATURE: APPLICATION TO THIN FILM SOLAR CELLS

Growth of silicon thin layer by Liquid Phase Epitaxy (LPE) at low temperature (800 °C) can be an attractive technique to fabricate low cost photovoltaic cells. Using a two baths technique, one can remove native oxide and then obtain homogeneous layers presenting a p/p+ structure. Short circuit current of 19 mA/cm² and conversion efficiency of 4.7% are obtained with 12 µm thick layer.Growth of silicon thin layer by Liquid Phase Epitaxy (LPE) at low temperature (800 °C) can be an attractive technique to fabricate low cost photovoltaic cells. Using a two baths technique, one can remove native oxide and then obtain homogeneous layers presenting a p/p+ structure. Short circuit current of 19 mA/cm² and conversion efficiency of 4.7% are obtained with 12 µm thick layer

Evaluation of factors influencing the performance of Kenyan Secondary School Students in English Grammar: A Case of Nyamaiya Division, Nyamira County, Kenya.

This study assessed the factors influencing the performance of secondary school students in English Grammar in Nyamaiya Division, Nyamira County. The study employed 31 public Secondary schools of which seventeen are day and fourteen are boarding schools. Sex was not a factor in the study. There were 150 respondents (31 head teachers, 31 deputies, 30 students and 58 teachers of English). Purposive and simple random sampling techniques were used in selecting the sample for the study. Five point likert type scale questionnaires were used to obtain data for the study. 150 questionnaires were administered to 150 respondents which covered the following areas: influence of mother tongue, problem areas in English grammar, academic and professional qualifications and experience of these teachers. The objectives were: to investigate the attitude secondary school students have towards English grammar, to find out how mother tongue impacts on learning English grammar in secondary schools, to establish the areas in English grammar that are problematic to students in secondary schools and to find out the academic and professional qualifications of teachers teaching English grammar to students in secondary schools. Teacher’s responses on attitude indicated that most of the students did not like English grammar. Regarding influence of mother tongue on performance in English grammar, the study showed that most of the students were influenced by mother tongue while others were not. On problem areas in English majority of the students experienced problems in the use of phrasal verbs and the use of auxiliaries. Other problems experienced are the use of punctuation marks, poor handwriting of the students and lack of practice in English. Majority of these teachers had degrees and some had KCSE certificates and very few had a master’s degree. Most of the sampled schools had not taught the subject for more than five years and some had taught the subject for more than 20 years. The data collected was analyzed by use of descriptive statistics and the chi – square test using the SPSS package. Recommendations based on the findings were made to guide policy makers to find appropriate ways to improve on performance in English grammar. Key words: evaluation, English Grammar, Nyamaiya Division, Nyamira Count