Calculated vs. Experimental Values for Volume and Surface Resistivity in Various Polymer Compounds

Versatile due to their resistance to high stress environments including but not limited to extreme temperature, pressure, and stress, polymers additionally have many uses in electrical applications wherein antistatic or conductive properties are preferential, i.e. conductive seals, oil pipeline spheres, and gaskets, to name a few. Being a complex material, many factors may affect the electrical resistivity of a given polymer compound including type and amount of carbon black, type of rubber, cure time and temperature, and dispersion, amongst other factors. External conditions such as relative humidity and temperature also play key roles. This paper will analyze five different rubber compounds by examining the difference between experimental and calculated volume and surface resistivity in both high and low humidity conditions

The expression and localisation of membrane transporters and P450 enzymes along the longitudinal and crypt-villus axes of the rat intestine and their response to oral imatinib

PhD ThesisA reduction in oral bioavailability of a wide range of drug compounds may occur following efflux of drug substrates into the intestinal lumen mediated by ATP dependent ABC transporters MDR1, MRP2 and BCRP and/or by enteric metabolism of drug compounds by CYP450 enzymes. Furthermore, inter-individual variability in the expression and function of key drug disposition proteins, which may occur following a regime of drug treatment, has the potential to cause altered pharmacokinetic profiles leading to failure of therapy. This thesis aimed to establish mRNA and protein expression of key drug transporter proteins and CYP450 enzymes both along the length of the intestine and across the crypt-villus axis using NanoString mRNA technology and immunohistochemistry. Key findings include; a) evidence for cytoprotection of the crypt cells distinct from enterocytes, b) a lack of correlation between Mrp2 mRNA and protein expression in the rat small intestine, with a paucity of brush-border protein in all regions, c) using the M70 antibody, Bcrp protein was immunolocalised to the lateral cell membranes of cryptal epithelial in the duodenum, jejunum and ileum with no apparent protein expression above the crypt-villus junction. Oral administration of the tyrosine kinase inhibitor imatinib mesylate was found to cause significant induction of Cyp1a1 mRNA expression with maximal induction in ileum samples showing an average 169-fold increase in expression. Immunohistochemistry indicates an associated increase in Cyp1a1 protein levels. In addition intestinal exposure to imatinib was found to cause significant changes in mRNA expression levels of genes including Mdr1a and Bcrp. This thesis presents key differences with regards to protein localisation of ABC transporters proposed to play an important role in conferring intestinal drug resistance between rat and human tissues and highlights the high levels of complexity associated with oral drug delivery and intestinal absorption

A Comparison of Appalachian and Non-Appalachian Kentucky DUI Offenders

Background: Driving under the influence has been an overlooked consequence of the opioid epidemic. Although recent reports have highlighted the increased prevalence of DUI in rural communities and the extensive mental health problems and criminal and drug use histories among rural Appalachian DUI offenders, it is unclear how Appalachian DUI populations compare to DUI offenders in other regions. Purpose: To help fill this void in the literature, the current study uses a statewide sample to examine how Appalachian DUI offenders differ from non-Appalachian DUI offenders in a predominantly rural state. Methods: Assessment records were examined for 11,640 Kentucky DUI offenders who completed an intervention in 2017. Appalachian DUI offenders were compared to non-Appalachian metro and nonmetro DUI offenders. Demographic information, DUI violation details, DSM-5 substance-use disorder criteria, and referral information were compared using ANCOVAs and logistic regression models. Results: More than one fourth of the sample were convicted in an Appalachian county. Compared to non-Appalachian DUI offenders, Appalachian offenders were significantly older and more likely to have a prior DUI conviction, to meet DSM-5 criteria for a drug-use disorder, and to drive while drug-impaired. Referral and intervention compliance also varied across groups. Implications: Results suggest that Appalachian DUI offenders are more drug-involved and have increased risk of recidivism. Findings indicate a need for practitioners to consider the distinct needs of Appalachian DUI offenders during service delivery. Future research should explore alternative intervention methods for preventing continued impaired driving in Appalachia given limited treatment availability in the region

Investigation of the Synthesis and Optoelectronic Properties of Ultrasmall CdSe Quantum Dots

Traditional, or 1st generation, solar cells have a theoretical upper limit of 33% power conversion efficiency based on the thermodynamic limitation of the single p-n junction cell design. This limitation is known as the Shockley-Queisser limit and methods to design solar cells to circumvent it have been creative, with a significant part of the field focused on quantum dot (QD) based systems. With theoretical efficiencies ranging between 44 and 67% for one sun concentration, QD solar cell designs are clearly superior to the limits of 1st generation solar cells. However, maximum achieved efficiencies for QD-based designs are far lower at present, with the current record at ~13%. These low efficiencies are caused in part by the fact that these cell types absorb in relatively narrow regions of the solar spectrum, thereby using only a fraction of the photons incident upon the earth’s surface. A broad absorption solar device would present an opportunity for unparalleled absorption capability. In that vein, this thesis work has focused on the investigation of the electronic band structure of ultrasmall CdSe QDs. Below 2 nm in diameter, approximately 90% of the atoms in ultrasmall QDs are on the surface, making them highly disordered structures. When excited by UV light, CdSe QDs in the ultrasmall size regime emit white light, i.e. all colors of the visible spectrum. The cause of this unpredicted behavior has been attributed to two possible hypotheses: 1) a multitude of defect states or 2) fluxionality, a process in which bonds between neighboring atoms are constantly being made and broken, resulting in conformational and electronic fluctuations. Determining which model most accurately describes these QDs will allow for the strategic manipulation of this single material that possesses either many midgap energy states (defect hypothesis) or a constantly fluctuating bandgap (fluxionality hypothesis) with the goal of a broad absorption solar cell in mind. Ultrasmall CdSe QDs were synthesized in the non-commercially available solvent, N-oleoylmorpholine (NOM). Differences in the purity of NOM batches had the capability to alter QD radiative relaxation pathways and therefore the kinetics of NOM formation were investigated. Using a test matrix with a range of reaction temperatures (110-170 °C) and morpholine feed rates (250-1000 μL/hr), the rate law for the formation of NOM was derived, in addition to chemical analysis via infrared (IR) spectroscopy and structural analysis of NOM via solution state nuclear magnetic resonance (NMR) spectroscopy. Importantly, this contribution to the kinetics of an open-air, low-temperature, single-size synthesis route for ultrasmall QDs should allow for more facile scale up. Next, the sensitivity of the QD band structure based on the environment of the surface of the QDs was examined by 1) ligation and 2) alteration of dielectric environment. First, QDs were ligated with one of the following: dodecanethiol, oleic acid, piperidine, or benzenesulfonic acid monohydrate. Second, the absorption and emission characteristics and stability of the QDs in solvents with dielectric constants ranging from 2.4 (toluene) to 78.4 (water) were analyzed both via experimental methods and simulation. Following initial studies, the QDs in these different dielectric systems were taken to Brookhaven National Labs (BNL) and examined via x-ray absorption spectroscopy (XAS), which yielded information on the nature of the Cd-Se bond as a function of the QD surface environment. These findings are compared to simulations of thermodynamic and optoelectronic properties of CdSe clusters conducted across a range of temperatures and dielectric constants. Finally, ultrasmall CdSe QDs were incorporated into metal oxide mesoporous structures, which served as the active material in QD-sensitized solar cells. The performance of these solar cells was evaluated via linear sweep voltammetry, which allows for the measurement of the open circuit voltage (VOC), the short circuit current (ISC), the power conversion efficiency (PCE), and the fill factor (FF). It was found that the greater the overlap of the valence band of the QDs with the metal oxide substrate, the higher the PCE of the cell; this is attributed to hole (h+) transport. The PCE of QD cells was found to be highly correlated to the location of the valence band in relation to the energy level of absolute vacuum (0 eV) by an exponential decay function

Digitally mediated design : using computer programming to develop a personal design process

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Architecture, 2000.Includes bibliographical references (p. 242-251).This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.This thesis is based on the proposal that the current system of architectural design education confuses product and process. Students are assessed through, and therefore concentrate on, the former whilst the latter is left in many cases to chance. This thesis describes a new course taught by the author at M IT for the last three years whose aim is to teach the design process away from the complexities inherent in the studio system. This course draws a parallel between the design process and the Constructionist view of learning, and asserts that the design process is a constant learning activity. Therefore, learning about the design process necessarily involves learning the cognitive skills of this theoretical approach to education. These include concrete thinking and the creation of external artifacts to develop of ideas through iterative, experimental, incremental exploration. The course mimics the Constructionist model of using the computer programming environment LOGO to teach mathematics. It uses computer programming in a CAD environment, and specifically the development of a generative system, to teach the design process. The efficacy of such an approach to architectural design education has been studied using methodologies from educational research. The research design used an emergent qualitative model, employing Maykut and Morehouse's "interpretive descriptive" approach (Maykut & Morehouse, 1994) and Glaser and Strauss's Constant Comparative Method of data analysis (Glaser & Strauss, 1967). Six students joined the course in the Spring 1999 semester. The experience of these students, what and how they learned, and whether this understanding was transferred to other areas of their educational process, were studied. The findings demonstrated that computer programming in a particular pedagogical framework, can help transform the way in which students understand the process of designing. The following changes were observed in the students during the course of the year: Development of understanding of a personalized design process; move from using computer programming to solve quantifiable problems to using it to support qualitative design decisions; change in understanding of the paradigm for computers in the design process; awareness of the importance of intra personal and interpersonal communication skills; change in expectations of, their sense of control over, and appropriation of, the computer in the design process; evidence of transference of cognitive skills; change from a Behaviourist to a Constructionist model of learning.by Megan Yakeley.Ph.D

Small business owners: too busy to train?

Purpose – The reason often cited for the poor relationship between small businesses and their uptake of vocational education and training is that small business owner-managers claim that they are too busy to engage in training or any type of learning activity and that most training is of little value to them. The aim of the research is to examine the relationship between these factors. Design/methodology/approach – Using qualitative research methods the study collected data of the knowledge, attitudes and needs of small business owner-managers, both before and after participation in a training program. Findings – This study has indicated that small business owners are interested in skills development and training opportunities, provided that they are directly applicable to the current situation in their business, and as long as the delivery process is carefully structured in terms of location, time of day, and length of session. Practical implications – The success of a human resource management training program offers both an incentive for other educators to continue to pursue small business participation and useful guidelines for the implementation and the development of new programs for the small business sector. Originality/value – The approach taken in this research has offered important insights into the value of training and how it is evaluated by small business owner-managers. This is important as owner managers are the primary decision makers about whether or not training takes place

Staying Out: Reentry Protective Factors Among Rural Women Offenders

The current study examines protective factors for women who transition from county jails to rural Appalachian communities, areas with limited health and behavioral health services. The study included drug-using women recruited from three jails in rural Appalachia and followed-up at 12-months post-release. Analyses focused on differences between women who remained in the community and those who returned to custody, as well as a multivariate model to determine protective factors for reentry success. At the bivariate level, staying out of jail was associated with being older, having a job, not using drugs, stable housing, receiving health treatment, and having prosocial peers. In the multivariate model, the most robust predictors of staying out of jail were drug use abstinence, health care utilization, and prosocial peers. Most research on criminogenic needs associated with reentry success have focused on men, and most focused on reentry to urban communities where services and resources are more accessible. These findings have important implications for criminal justice systems to implement reentry programs for women offenders during the transition to the community

Molecular Mechanisms for Drug Hypersensitivity Induced by the Malaria Parasite's Chloroquine Resistance Transporter

Mutations in the Plasmodium falciparum ‘chloroquine resistance transporter’ (PfCRT) confer resistance to chloroquine (CQ) and related antimalarials by enabling the protein to transportthese drugs away from their targets within the parasite’s digestive vacuole (DV). However, CQ resistance-conferring isoforms of PfCRT (PfCRTCQR) also render the parasite hypersensitive to a subset of structurally-diverse pharmacons. Moreover, mutations in PfCRTCQR that suppress the parasite’s hypersensitivity to these molecules simultaneously reinstate its sensitivity to CQ and related drugs. We sought to understand these phenomena by characterizing the functions of PfCRTCQR isoforms that cause the parasite to become hypersensitive to the antimalarial quinine or the antiviral amantadine. We achieved this by measuring the abilities of these proteins to transport CQ, quinine, and amantadine when expressed in Xenopus oocytes and complemented this work with assays that detect the drug transport activity of PfCRT in its native environment within the parasite. Here we describe two mechanistic explanations for PfCRT-induced drug hypersensitivity. First, we show that quinine, which normally accumulates inside the DV and therewithin exerts its antimalarial effect, binds extremely tightly to the substrate-binding site of certain isoforms of PfCRTCQR. By doing so it likely blocks the normal physiological function of the protein, which is essential for the parasite’s survival, and the drug thereby gains an additional killing effect. In the second scenario, we show that although amantadine also sequesters within the DV, the parasite’s hypersensitivity to this drug arises from the PfCRTCQR-mediated transport of amantadine from the DV into the cytosol, where it can better access its antimalarial target. In both cases, the mutations that suppress hypersensitivity also abrogate the ability of PfCRTCQR to transport CQ, thus explaining why rescue from hypersensitivity restores the parasite’s sensitivity to this antimalarial. These insights provide a foundation for understanding clinically-relevant observations of inverse drug susceptibilities in the malaria parasite

Therapeutic Targeting of IL-11 for Chronic Lung Disease

Interleukin (IL)-11 was originally recognized as an immunomodulatory and hematopoiesis-inducing cytokine. However, although IL-11 is typically not found in healthy individuals, it is now becoming evident that IL-11 may play a role in diverse pulmonary conditions, including IPF, asthma, and lung cancer. Additionally, experimental strategies targeting IL-11, such as humanized antibodies, have recently been developed, revealing the therapeutic potential of IL-11. Thus, further insight into the underlying mechanisms of IL-11 in lung disease may lead to the ability to interfere with pathological conditions that have a clear need for disease-modifying treatments, such as IPF. In this review, we outline the effects, expression, signaling, and crosstalk of IL-11 and focus on its role in lung disease and its potential as a therapeutic target

H1517+656: the Birth of a BL Lac Object?

H1517+656 is an unusual source, even for a BL Lac object. It is one of the most luminous BL Lacs known, with extreme emission properties at radio, optical, and X-ray frequencies. Furthermore, in our WFPC2 snapshot survey we discovered a series of peculiar arcs describing a 2.4 arcsec radius ring surrounding the source. This paper describes follow-up observations with additional WFPC2 bands and the STIS longpass filter, which have revealed this structure to be the remnants of a very recent galaxy merger. Population synthesis modelling has shown that regions of the arcs have stellar populations with age < 20 Myrs. Additionally, the circularity of the arcs indicates that the plane of the collision and hence accretion is very close to the plane of the sky. Given that BL Lac jets are thought to be aligned with the line of sight, this observation may provide a direct link between the transfer of angular momentum in an interaction and the generation of a radio source.Comment: 29 pages, 9 figures, accepted for publication in Ap