Novel polymer constructs for controlled release and presentation of topographic cues in support of neuronal cells

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (leaves 25-26).In order to improve nerve healing, a new treatment that uses conductive polymer scaffolds to bridge gaps between damaged nerve ends and deliver drugs controllably was explored. In order to optimize neuron growth across scaffolding a neuronal scaffold designed with an electrically conductive polymer, polypyrrole (PPy), will be used as a substrate to enhance nerve cell interaction in vitro. The polymer will be analyzed for the capacity to influence cellular phenotype, including via controlled biomolecular delivery and surface topography. This thesis showed that all these concepts are possible and begins to optimize these characteristics. Successfully optimization of these scaffold characteristics will provide a novel method for treating injury in the central nervous system.by Asiri Ediriwicikrema.S.B

Vibrational Stability of NLC Linac accelerating structure

The vibration of components of the NLC linac, such as accelerating structures and girders, is being studied both experimentally and analytically. Various effects are being considered including structural resonances and vibration caused by cooling water in the accelerating structure. This paper reports the status of ongoing work.Comment: 3 pages 8 figures Presented at EPAC 2002 Paris Franc

Cten promotes Epithelial–Mesenchymal Transition (EMT) in colorectal cancer through stabilisation of Src

Cten is an oncogene promoting EMT in many signaling pathways, namely through Snail. We investigated whether Cten function could be mediated through Src. Cten levels were modulated by forced expression in HCT116 and gene knockdown in SW620 CRC (colorectal cancer) cell lines. In all cell lines, Cten was a positive regulator of Src expression. The functional importance of Src was tested by simultaneous Cten overexpression and Src knockdown. This resulted in abrogation of Cten motility-inducing activity and reduction of colony formation ability together with failure to induce Cten targets. In SW620ΔCten reduced Src expression increased following restoration of Cten, also leading to increased cell motility and colony formation, which were lost if Src was concomitantly knocked down. By qRT-PCR we showed modulation of Cten had no effect on Src mRNA. However, a CHX pulse chase assay demonstrated stabilization of Src protein by Cten. Finally, expression of Cten and Src was tested in a series of 84 primary CRCs and there was a significant correlation between them (P = 0.001). We conclude that Src is a novel and functionally important target of the Cten signaling pathway and that Cten protein causes post-transcriptional stabilization of Src in promoting EMT and possibly metastasis in CRC

Burnout Syndrome Among Respiratory Therapists in Saudi Arabia

Background: Burnout (BO) is a consequence of chronic work-related stress exposure and impacts healthcare workers\u27 performance, efficiency, and quality of care. Purpose: The study aimed to assess the BO among respiratory therapists (RTs) in Saudi Arabia and examine the association between BO and sociodemographic data and professional satisfaction. Methods: A cross-sectional study involving a convenience sample of RTs in Saudi Arabia was conducted utilizing the Maslach Burnout Inventory (MBI) in addition to questions regarding sociodemographic information and professional satisfaction. Three dimensions typify BO syndrome in the MBI questionnaire: emotional exhaustion, depersonalization, and low personal accomplishment. Statistical Package for the Social Sciences (SPSS) version 27.0 was used to analyse the data. To make comparisons between two continuous variables, independent samples t-tests were used. A one-way ANOVA test was used for factors with more than two categories. Two hundred thirty-six RTs (N=236) were surveyed in this study. The majority of the respondents were male n=130 (55.1%), single n=140 (59.3%), and lived in the central region n=136 (57.6%). The age of the participating RTs in the study ranged from 20 to 58 years, with an average of 28.5 years (SD±5.08). Results: The results showed that RTs had a high level of emotional exhaustion with a mean of 31.97, a moderate level for depersonalization with a mean of 11.39, and a moderate level for lack of personal accomplishment with a mean of 33.58. Age, gender, the role of the RTs, hours of work, and shift schedule of the participants were associated with BO. The workload was the most work factor among RTs associated with BO. Professional satisfaction of work-life balance, the current job, and monthly income were related to the burnout levels across the three subscales. Conclusion: This study was the first to explore BO by MBI and related factors among RTs in Saudi Arabia. Burnout seemed to be a common problem among RTs in Saudi Arabia and was associated with sociodemographic information and professional satisfaction. The findings may help to develop effective intervention strategies to limit and prevent BO. More prospective studies are required with a larger number of participants of RTs

Internet Addiction and its Predictors in Guilan Medical Sciences Students, 2012

Background: Internet is one of the technologies of the modern era that is being extensively used around the world. It is believed that excessive Internet use can be pathological and addictive. Though, academic use of the Internet is primarily intended for learning and research, students are one of the groups at risk of Internet addiction. Objectives: Due to the expanding use of Internet among the university students, this study was conducted to examine the Internet addiction and its predictors among Guilan University of Medical Sciences students. Materials and Methods: A cross-sectional study was conducted on 583 students during the first semester of 2012. A two-stage stratified random sampling was conducted and a two-part instrument was used for data collection. The first part of the instrument was consisted of questions about demographic characteristics and the second part was the Young's Internet addiction inventory. Chi-square, Kruskal-Wallis testes, Spearman correlation coefficient and ranked logistic regression were used for data analysis. Results: About 5.7% of the students were moderately dependent to the Internet, while 44.1% were at risk for Internet addiction. Significant relationships were observed between the Internet addiction with age (P < 0.001), gender (P < 0.001), marital status (P < 0.001), major (P = 0.016), Grade point average (P = 0.017), semester of studying (P = 0.009) and student residence place (P = 0.014). However, no significant relationship was observed between the internet addiction score and level of discipline, parental job status and education level or the students’ accommodation. Conclusion: About half of the participants in this study were at risk of Internet addiction. This finding can be a warning sign for the authorities in universities to pay more attention to this issue. A wide range of education along with empowering programs may be needed to inform the university students about the advantages and disadvantages of internet and the correct manner of using it

Vibrational Stability of NLC Linac and Final Focus Components

Vertical vibration of linac components (accelerating structures, girders and quadrupoles) in the NLC has been studied experimentally and analytically. Effects such as structural resonances and vibration caused by cooling water both in accelerating structures and quadrupoles have been considered. Experimental data has been compared with analytical predictions and simulations using ANSYS. A design, incorporating the proper decoupling of structure vibrations from the linac quadrupoles, is being pursued.Comment: 3 pages, 8 figures presented at the LINAC 2002 conference, Gyeongju Kore

Effect of Cooling Water on Stability of NLC Linac Components

Vertical vibration of linac components (accelerating structures, girders and quadrupoles) in the NLC has been studied experimentally and analytically. Effects such as structural resonances and vibration caused by cooling water both in accelerating structures and quadrupoles have been considered. Experimental data has been compared with analytical predictions and simulations using ANSYS. A design, incorporating the proper decoupling of structure vibrations from the linac quadrupoles, is being pursued.Comment: 6 Pages 13 Figures Presented at The Nanobeam 2002 Workshop (Lausanne Switzerland

Social and Economic Factors that Influence Health Outcomes in Family Medicine

Over the last twenty years, the social determinants of health (SDOH) have gained more and more attention in the public health community. SDOH are non-medical elements that may be significantly impacted by social policies and have an impact on health. The increasing variety that exists within our societies makes it absolutely necessary for us to incorporate into undergraduate medical education social determinants of health such as racial factors, financial instability, partner violence, insufficient accessibility to transportation, and inadequate social supports, as well as the crucial role of health education.&nbsp; Nonetheless, a growing body of research indicates that a variety of health outcomes are fundamentally caused by socioeconomic variables including wealth, income, and education together. In this review we highlight the influence of socio-economic factors on health outcomes, approaches to incorporate social determinants of health in family medicine practice, and we also talk about challenges and solutions in addressing social determinants in family medicine. The objective of this research was to assess the impact of social determinants of health on family medicine practice in which socioeconomic determinants of health might have an effect on health outcomes and healthcare delivery within the context of a family medicine clinical environment

On carbon and oxygen isotope ratios in starburst galaxies: New data from NGC253 and Mrk231 and their implications

Using the IRAM 30-m telescope, CN and CO isotopologues have been measured toward the central regions of the nearby starburst galaxy NGC253 and the prototypical ultraluminous infrared galaxy Mrk231. In NGC253, the 12C/13C ratio is 40+-10. Assuming that the ratio also holds for the CO emitting gas, this yields 16O/18O = 145+-36 and 16O/17O = 1290+-365 and a 32S/34S ratio close to that measured for the local interstellar medium (20-25). No indication for vibrationally excited CN is found. Peak line intensity ratios between NGC253 and Mrk231 are ~100 for 12C16O and 12C18O J=1-0, while the ratio for 13C16O J=1-0 is ~250. This and similar 13CO and C18O line intensities in the J=1-0 and 2-1 transitions of Mrk231 suggest 12C/13C ~ 100 and 16O/18O ~ 100, in agreement with values obtained for the less evolved ultraluminous merger Arp220. Also accounting for other extragalactic data, 12C/13C ratios appear to vary over a full order of magnitude, from >100 in ultraluminous high redshift galaxies to ~100 in more local such galaxies to ~40 in weaker starbursts not undergoing a large scale merger to 25 in the Central Molecular Zone of the Milky Way. With 12C being predominantly synthesized in massive stars, while 13C is mostly ejected by longer lived lower mass stars at later times, this is qualitatively consistent with our results of decreasing carbon isotope ratios with time and rising metallicity. It is emphasized, however, that both infall of poorly processed material, initiating a nuclear starburst, as well as the ejecta from newly formed massive stars (in particular in case of a top-heavy stellar initial mass function) can raise the carbon isotope ratio for a limited amount of time.Comment: Accepted by Astronomy & Astrophysics, 6 figures, 4 table

Mechanisms of Stereodirecting Participation and Ester Migration from Near and Far in Glycosylation and Related Reactions

This review is the counterpart of a 2018 Chemical Reviews article (Adero, P. O.; Amarasekara, H.; Wen, P.; Bohe, L.; Crich, D. Chem. Rev. 2018, 118, 8242-8284) that examined the mechanisms of chemical glycosylation in the absence of stereodirecting participation. Attention is now turned to a critical review of the evidence in support of stereodirecting participation in glycosylation reactions by esters from either the vicinal or more remote positions. As participation by esters is often accompanied by ester migration, the mechanism(s) of migration are also reviewed. Esters are central to the entire review, which accordingly opens with an overview of their structure and their influence on the conformations of six-membered rings. Next the structure and relative energetics of dioxacarbeniun ions are covered with emphasis on the influence of ring size. The existing kinetic evidence for participation is then presented followed by an overview of the various intermediates either isolated or characterized spectroscopically. The evidence supporting participation from remote or distal positions is critically examined, and alternative hypotheses for the stereodirecting effect of such esters are presented. The mechanisms of ester migration are first examined from the perspective of glycosylation reactions and then more broadly in the context of partially acylated polyols.Peer reviewe