Inkjet printed multimetal microelectrodes on PDMS for functionalized microfluidic systems

A novel direct method of metal microelectrode patterning on polydimethylsiloxane (PDMS) using inkjet printed gold and silver nanoparticles to form electrochemical sensors is presented. Inkjet printing is an additive microfabrication technique enabling microelectrode patterning directly over large areas at low-temperatures. (3-mercaptopropyl) trimethoxysilane (MPTMS) to promote PDMS surface wettability and improve metal adhesion and a pixel-printing subsampling method to overcome surface tension driven ink-droplet coalescence, are then employed to form a robust fabrication process. The resulting printed gold and silver microelectrodes exhibit good compactness, continuity and conductivity, and are used to manufacture functionalized microfluidic systems with in-situ three-electrode electrochemical sensors.published_or_final_versio

Nationalism Constructed Against “Others”: Chiapas’s Anti-Chinese Movement And State Formation In Postrevolutionary Mexico

This thesis examines the motives and causes of the anti-Chinese movement during Mexican postrevolutionary period in Chiapas, Mexico, where the Chinese population was less dense and a region historically distant from the political center. Drawing from the evidence, I argue that the anti-Chinese movements in the early 1930s was linked to the newly established Partido Nacional Revolucionario (PNR), the party that later became the one that dominated Mexican politics. The anti-Chinese movement in Chiapas also demonstrates PNR’s indirect control over the historically rebellious Chiapas state government and the negotiation of power between the center and periphery. In addition, this thesis also applies the theories of Gerardo Rénique and Pierre Bourdieu on nation state building to this particularly case of anti-Chinese movement in Chiapas in order to examine the apparatus of the postrevolutionary state and the means the new state employed to accumulate various forms of political and social capital and enhance its legitimacy

Data mining cDNA microarray experiment with a GEE approach

The use of microarray technology provides access to the simultaneous expression of thousands of genes and is revolutionizing the scientic community of functional genomics. This thesis investigates a cDNA microarray experiment with the goal of discovering dierentially expressed genes across several factors. The analysis rst "normalizes" the data through the VSN package which is a robust calibration and variance stabilization software that removes systematic bias which could impair the analysis. A generalized estimating equation (GEE) approach is used to model the data and investigate the null hypothesis of no dierence in expression levels. To accommodate the numerous hypothesis being tested, we used the q-value method to control the false discovery rate of the analysis. The analytical procedures are performed by using the statistical software packages SAS r and R

Effect of membrane thickness and unsaturation on dye efflux rates induced by [delta]-Lysin from phosphatidylcholine vesicles

An important region of the cellular membrane that appears to have major influence on membrane-peptide interactions is the hydrophobic acyl chain region. In this study two lipid series were used to determine whether specificity towards membranes is influenced by acyl chain length, or membrane thickness, or by the degree of acyl chain unsaturation. Additionally, this quantitative investigation also provided insight on the effects of free volume and bilayer elasticity. The interaction of the peptide d-lysin, a 26-residue peptide, to lipid bilayers was studied using stopped-flow fluorescence. Samples of carboxyfluorescein filled vesicles of various lipid concentrations were mixed with d-lysin resulting in dye efflux. The experimental curves of carboxyfluorescein efflux as a function of time were measured at lipid concentrations ranging from 12.5 µM to 200 µM. Constant t values were calculated to determine the weighted average of the relaxation times of each carboxyfluorescein release function. It was found the main cause for dye efflux was a thinner membrane. Also, bending of the membrane was found to be dependent on the thickness of the bilayer. The stretching ability of the membrane had less significance in peptide insertion. As a result of bending stiffness being a major factor for peptide insertion, it appears that d-lysin binds to the surface of the membrane due to the hydrophobic effect, and sink as a ‘wedge’ into the lipid bilayer

Dental Service Utilization among Urban and Rural Older Adults in China

Objectives: China's health care system is bifurcated in nature between rural and urban areas. In addition, there is a huge gap in socioeconomic status between rural and urban residents. The purpose of the study was to examine the factors related to dental visits among elders in rural and urban areas of Shanghai, China. Methods: Using a stratified random sampling method, a cross-sectional, face-to-face survey was conducted among elders aged 60 years and above in Shanghai during 2003-04. A total of 1,044 older respondents were included in the sample. Results: There was a significant urban and rural difference in dental visit rates over the 12-month period of the study. Results from the logistic regression analysis suggested that residing in urban areas was a significant positive factor related to dental visits. In addition, being younger, being able to pay out-of-pocket medical expenses, having had regular medical checkups, having a higher number of limitations because of chronic conditions, and being more concerned about eating a healthy diet were associated with increased odds of dental visits. Conclusions: Results suggest that urban–rural differences, as reflected in the socioeconomic status gap, disparity in medical insurance coverage, and access to dental care, have a significant impact on the use of dental services by Chinese elders. Individual sociodemographic characteristics, health status, and health attitude are important explanatory variables

Workforce Issues in Residential Care Facilities in Rural China

This study examined contemporary frontline workforce issues related to residential care for elders in rural China. Residential facilities in rural China are in transition from exclusively providing shelter to childless elders to providing long-term care for frail elders. These facilities are also under pressure to improve the quality of services that they provide. The study is based on in-depth interviews with administrators and field observations of facilities. The study focused on the following issues related to the workforce: recruitment and retention, training, work environment, workforce organization, regulations, compensation, and career ladders. The implications of resident characteristics for demands on the work force were examined. The study found that lack of skilled personnel is one of the major reasons that the overwhelming majority of facilities deny admission to frail and demented elders. Improving workers’ skill is critical if these facilities are to meet the increasing demand for institutional long-term care needs

Cognitive Function and Oral Health Among Community-Dwelling Older Adults

Background. Both oral health problems and cognitive impairment are relatively common among older adults. Poorer oral health appears to contribute to a decline in quality of life and to be related to various medical conditions. Little is known about the relationship of cognitive function to oral health among community-dwelling older adults. Methods. The sample included 1984 dentate community-dwelling older adults 60 years old or older from the National Health and Nutrition Examination Survey (NHANES, 1999-2002) who completed both the study cognitive measure and dental examination. Weighted descriptive and multivariate regression analyses were performed. Results. Multivariate analyses showed that cognitive function was associated with oral health. Individuals with lower cognitive scores had a higher number of decayed and missing teeth and a higher proportion of periodontitis sites. The predicted number of decayed teeth increased by 0.01 with each 1-point decrease in the Digit Symbol Substitution Test score; the number of missing teeth increased by 0.02; and the percentage of sites with periodontal disease increased by 0.02. In addition, individuals' sociodemographic characteristics, health behavior, and regular dental checkups were significantly associated with oral health. Conclusions. This study suggests that community-dwelling elders with lower cognitive function scores have greater deterioration of oral health. This study provides a preliminary knowledge base for the development of early intervention strategies to address oral health problems among older adults

Depressive symptoms and health problems among Chinese immigrant elders in the US and Chinese elders in China

Objectives: Researchers speculate that depression tends to be more prevalent among immigrant elders due to their lack of resources, acculturation stress, language problems, and social isolation. However, other characteristics of elderly immigrants, such as the healthy immigrant effect, may counteract these potential risk factors. This study examined whether depressive symptoms differed between Chinese immigrant elders and their counterparts in China and whether health conditions were similarly associated with depressive symptoms in these two samples. Methods: Depression and health information was collected from 177 Chinese immigrant elders in Boston, the US in 2000 and from 428 education and gender-matched elders in Shanghai, China in 2003. Results: Chinese immigrants had a significantly lower score on the modified Center for Epidemiologic Studies Depression Scale (CES-D) and its subscales: somatic symptoms and depressive affect. The association remained for the subscale depressive affect in multivariate analyses. Arthritis and back or neck problems were associated with a higher level of depressive symptoms among Chinese immigrants, while problems in walking were associated with depression among their counterparts in China. Pain was an underlying contributor to the association between depression and these health problems in both the groups. Conclusions: This study suggests that Chinese immigrant elders might be more resilient than their counterparts despite many challenges they face after moving abroad. With the growing number of older Chinese immigrants in the US, a better understanding of depressive symptoms is essential to provide culturally competent services to better serve this population

Are Contributory Behaviors Related to Culture? Comparison of the Oldest Old in the U.S. and in China

The purpose of this study is to examine the impact of culture on contributory behaviors within the context of family, friends, and neighbors among the oldest old in the United States and in China. The study was conducted in suburban areas of Boston in 1996 (n = 465), and later in 1999 a replication of the study was conducted by Chinese researchers in urban areas of Shanghai, China (n = 539). This study found some common factors such as objective measure of health status, assistance received from others, and group affiliation. However, many differences emerged in the study. The range of contributory behaviors toward friends is quite different between the two samples. Some of the correlates' impact is also culturally specific, such as sibling support. These differences reflect variation in respondents' social support as well as social structural differences. Findings from this study suggest that providing more opportunities for elders to participate in groups would facilitate their participation in volunteer activities and improve their overall well-being

Age Distribution and Risk Factors for the Onset of Severe Disability Among Community-Dwelling Older Adults with Functional Limitations

This study examines age distribution and risk factors for the onset of severe disability among community-dwelling older adults with functional limitations. Data were obtained from the initial community-dwelling sample (n = 6,088) of the National Long-Term Care Survey in 1982 and the follow-up interviews in 1984, 1989, 1994, and 1999. Multiple proportional hazard regression was conducted using age at onset of severe disability as the dependent variable. Explanatory variables included chronic diseases and sociodemographic and personal char-acteristics. Of the 3,485 elders who were not severely disabled initially, 1,364 were identified as developing severe disability over time. The onset age ranged from 66 to 109 years with the peak occurring at 82 to 83 years. The predictors for earlier onset of severe disability were paralysis, arthritis, obesity, hypertension, and middle education level (Grades 9-12). These findings provide practical implications for identifying at-risk individuals and developing health behavior interventions to delay onset of severe disability