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Articles 8401 - 8430 of 11833

Full-Text Articles in Physical Sciences and Mathematics

Heterometallic Titanium–Gold Complexes Inhibit Renal Cancer Cells In Vitro And In Vivo, Jacob Fernandez-Gallardo, Benelita T. Elie, Tanmoy Sadhukha, Swayam Prabha, Mercedes Sanau, Susan A. Rotenberg, Joe W. Ramos, Maria Contel Jan 2015

Heterometallic Titanium–Gold Complexes Inhibit Renal Cancer Cells In Vitro And In Vivo, Jacob Fernandez-Gallardo, Benelita T. Elie, Tanmoy Sadhukha, Swayam Prabha, Mercedes Sanau, Susan A. Rotenberg, Joe W. Ramos, Maria Contel

Publications and Research

Following recent work on heterometallic titanocene–gold complexes as potential chemotherapeutics for renal cancer, we report here on the synthesis, characterization and stability studies of new titanocene complexes containing a methyl group and a carboxylate ligand (mba ¼ S–C6H4–COO) bound to gold(I)-phosphane fragments through a thiolate group [(h-C5H5)2TiMe(m-mba)Au(PR3)]. The compounds are more stable in physiological media than those previously reported and are highly cytotoxic against human cancer renal cell lines. We describe here preliminary mechanistic data involving studies on the interaction of selected compounds with plasmid (pBR322) DNA used as a model nucleic acid, and with selected protein kinases from a …


The Genesis And Emergence Of Community-Associated Methicillin-Resistant Staphylococcus Aureus (Ca-Mrsa): An Example Of Evolution In Action?, Alan L. Gillen, Jason Conrad, Michael Cargill Jan 2015

The Genesis And Emergence Of Community-Associated Methicillin-Resistant Staphylococcus Aureus (Ca-Mrsa): An Example Of Evolution In Action?, Alan L. Gillen, Jason Conrad, Michael Cargill

Faculty Publications and Presentations

Staphylococcus aureus infections are a common cause of disease, particularly in colonized persons. Recently, a series of published articles have reported that community-acquired methicillin-resistant S. aureus (CA-MRSA) strains are evolving and increasingly becoming prevalent in households while health care acquired MRSA (HA-MRSA) is declining in the USA. The changing superbugs have often been used as an example of evolution in action. Although MRSA infections have become increasingly reported in the community, population-based studies of students preparing for the health professions having S. aureus and MRSA colonization are lacking. During the 2014–2015 school year 544 students were tested for MRSA carriage …


The Multimodal Brain Tumor Image Segmentation Benchmark (Brats), Bjoern H. Menze, Andras Jakab, Stefan Bauer, Jayashree Kalpathy-Cramer, Khan M. Iftekharuddin, Syed M.S. Reza Jan 2015

The Multimodal Brain Tumor Image Segmentation Benchmark (Brats), Bjoern H. Menze, Andras Jakab, Stefan Bauer, Jayashree Kalpathy-Cramer, Khan M. Iftekharuddin, Syed M.S. Reza

Electrical & Computer Engineering Faculty Publications

In this paper we report the set-up and results of the Multimodal Brain Tumor Image Segmentation Benchmark (BRATS) organized in conjunction with the MICCAI 2012 and 2013 conferences. Twenty state-of-the-art tumor segmentation algorithms were applied to a set of 65 multi-contrast MR scans of low-and high-grade glioma patients-manually annotated by up to four raters-and to 65 comparable scans generated using tumor image simulation software. Quantitative evaluations revealed considerable disagreement between the human raters in segmenting various tumor sub-regions (Dice scores in the range 74%-85%), illustrating the difficulty of this task. We found that different algorithms worked best for different sub-regions …


A Comparison Of Combined Overlap Block Fuzzy Cognitive Maps (Cobfcm) And Combined Overlap Block Neutrosophic Cognitive Map (Cobncm) In Finding The Hidden Patterns And Indeterminacies In Psychological Causal Models: Case Study Of Adhd, Hojjatollah Farahani, Florentin Smarandache, Lihshing Leigh Wang Jan 2015

A Comparison Of Combined Overlap Block Fuzzy Cognitive Maps (Cobfcm) And Combined Overlap Block Neutrosophic Cognitive Map (Cobncm) In Finding The Hidden Patterns And Indeterminacies In Psychological Causal Models: Case Study Of Adhd, Hojjatollah Farahani, Florentin Smarandache, Lihshing Leigh Wang

Branch Mathematics and Statistics Faculty and Staff Publications

In spite of researchers’ concerns to find causalities, reviewing the literature of psychological studies one may argue that the classical statistical methods applied in order to find causalities are unable to find uncertainty and indeterminacies of the relationships between concepts.

In this paper, we introduce two methods to find effective solutions by identifying “hidden” patterns in the patients’ cognitive maps. Combined Overlap Block Fuzzy Cognitive Map (COBFCM) and Combined Overlap Block Neutrosophic Map (COBNCM) are effective when the number of concepts can be grouped and are large in numbers. In the first section, we introduce COBFCM, COBNCM, their applications, and …


Killing Adherent And Nonadherent Cancer Cells With The Plasma Pencil, Mounir Laroussi, Soheila Mohades, Nazir Barekzi Jan 2015

Killing Adherent And Nonadherent Cancer Cells With The Plasma Pencil, Mounir Laroussi, Soheila Mohades, Nazir Barekzi

Electrical & Computer Engineering Faculty Publications

The application of low temperature plasmas in biology and medicine may lead to a paradigm shift in the way various diseases can be treated without serious side effects. Low temperature plasmas generated in gas mixtures that contain oxygen or air produce several chemically reactive species that have important biological implications when they interact with eukaryotic or prokaryotic cells. Here, a review of the effects of low temperature plasma generated by the plasma pencil on different cancerous cells is presented. Results indicate that plasma consistently shows a delayed killing effect that is dose dependent. In addition, there is some evidence that …


Dimethylsulfide Gas Transfer Coefficients From Algal Blooms In The Southern Ocean, T. G. Bell, Warren J. De Bruyn, Christa A. Marandino, S. D. Miller, C. S. Law, Eric S. Saltzman Jan 2015

Dimethylsulfide Gas Transfer Coefficients From Algal Blooms In The Southern Ocean, T. G. Bell, Warren J. De Bruyn, Christa A. Marandino, S. D. Miller, C. S. Law, Eric S. Saltzman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Air-sea dimethylsulfide (DMS) fluxes and bulk air-sea gradients were measured over the Southern Ocean in February-March 2012 during the Surface Ocean Aerosol Production (SOAP) study. The cruise encountered three distinct phytoplankton bloom regions, consisting of two blooms with moderate DMS levels, and a high biomass, dinoflagellate-dominated bloom with high seawater DMS levels (> 15 nM). Gas transfer coefficients were considerably scattered at wind speeds above 5 m s(-1). Bin averaging the data resulted in a linear relationship between wind speed and mean gas transfer velocity consistent with that previously observed. However, the wind-speed-binned gas transfer data distribution at all wind …


A Quantum Theory Of Consciousness May Require A Paradigm Shift In Biology, Maurice Goodman Jan 2015

A Quantum Theory Of Consciousness May Require A Paradigm Shift In Biology, Maurice Goodman

Articles

It is often assumed that the known physical laws form a closed system and are complete. It is also assumed that biological theories require no additional principles that are fundamental other than those we already know. Assumptions such as these are acting as a barrier to progress in biological theories and an understanding of consciousness. This paper examines the unexplained inconsistencies among fundamental particles and forces and the fundamental gaps in our knowledge of biology and the cell in particular that may impact on such progress. Also, the laws of quantum mechanics are examined and found to be grossly incomplete. …


Curcumin: A Folklore Remedy From Kitchen On The Way To Clinic As Cancer Drug, Debasish Bandyopadhyay Jan 2015

Curcumin: A Folklore Remedy From Kitchen On The Way To Clinic As Cancer Drug, Debasish Bandyopadhyay

Chemistry Faculty Publications and Presentations

Numerous compounds are widely distributed in nature and many of these possess medicinal/biological/pharmacological activity. Curcumin, a polyphenol derived from the rhizomes (underground stems) of Curcuma longa Linn (a member of the ginger family, commonly known as turmeric) is a culinary spice and therapeutic used in India for thousands of years to induce color and flavor in food as well as to treat a wide array of diseases. The origin of turmeric as spice and folklore medicine is so old that it is lost in legend. Curcumin has many beneficial pharmacological effects which includes, but are not limited with, antimicrobial, anti-inflammatory, …


Predictive Analytics For Disease Condition Of Patients In Emergency Department, Azade Tabaie Jan 2015

Predictive Analytics For Disease Condition Of Patients In Emergency Department, Azade Tabaie

Wayne State University Theses

Emergency Departments (EDs) in hospitals are experiencing severe crowding and prolonged patient waiting times. The reported crowding in hospitals shows patients in hospital hallways, long waiting times and full occupancy of ED beds. ED crowding has several potential unfavorable effects including patients and staff frustration, lower patient satisfaction and poor health outcomes. The primary motivations behind this study are shortening the patients’ waiting time and improving patient satisfaction and level of care.

The very initial interaction between clinicians and a patient is recorded on nurse triage notes which contain details of the reason for patient’s visit including specific symptoms and …


2015 Abstracts Student Research Conference, Student Research Conference Jan 2015

2015 Abstracts Student Research Conference, Student Research Conference

Student Research Conference Select Presentations

No abstract provided.


Gene Expression Changes Reflect Clinical Response In A Placebo-Controlled Randomized Trial Of Abatacept In Patients With Diffuse Cutaneous Systemic Sclerosis, Eliza F. Chakravarty, Viktor Martyanov, David Fiorentino, Tammara A. Wood, David J. Haddon, Justin A. Jarrell, Paul Utz, Mark Genovese, Michael Whitfield, Lorinda Chung Jan 2015

Gene Expression Changes Reflect Clinical Response In A Placebo-Controlled Randomized Trial Of Abatacept In Patients With Diffuse Cutaneous Systemic Sclerosis, Eliza F. Chakravarty, Viktor Martyanov, David Fiorentino, Tammara A. Wood, David J. Haddon, Justin A. Jarrell, Paul Utz, Mark Genovese, Michael Whitfield, Lorinda Chung

Dartmouth Scholarship

Systemic sclerosis is an autoimmune disease characterized by inflammation and fibrosis of the skin and internal organs. We sought to assess the clinical and molecular effects associated with response to intravenous abatacept in patients with diffuse cutaneous systemic.


Nitrate In Private Wells:Knowledge, Oppinions,And Perceptions Of Stakeholders, Augustus D. Jaja Jan 2015

Nitrate In Private Wells:Knowledge, Oppinions,And Perceptions Of Stakeholders, Augustus D. Jaja

Walden Dissertations and Doctoral Studies

The purpose of this quantitative study was to examine data describing nitrate concentration and cases of congenital cardiac defects. Residents with private wells and other stakeholders need data to make informed environmental decisions about the adverse health implications of nitrate contamination of private well water. Researchers have examined the exposure of nitrate in contaminated groundwater, but they have not examined nitrate levels in unregulated water systems. This gap in the literature highlighted the need to provide nitrate data for future research and private well users. Guided by the social ecological model, a quantitative, cross-sectional, nonexperimental design was used to survey …


Correlations Between Childhood Obesity And Obesogenic Environmental Variables Within Durham County, North Carolina, Eureka Capri Daye Jan 2015

Correlations Between Childhood Obesity And Obesogenic Environmental Variables Within Durham County, North Carolina, Eureka Capri Daye

Walden Dissertations and Doctoral Studies

The application of geographic information systems was used to map obesogenic conditions by zip code tabulation areas in Durham County, North Carolina and evaluated associations between those conditions and the understudied area of early childhood obesity. Of the thirty one percent of the children in Durham County, North Carolina who were considered obese in 2010, four hundred and thirty three (1:5) 2 - 4 year old children who received supplemental nutrition services for women, infants and children were obese with BMI levels greater or equal to the 95th percentile and were used as the criterion variable in the study (N=433). …


Climate Change Implications For Health-Care Waste Incineration Trends During Emergency Situations, Emilia Mmbando Raila Jan 2015

Climate Change Implications For Health-Care Waste Incineration Trends During Emergency Situations, Emilia Mmbando Raila

Walden Dissertations and Doctoral Studies

Healthcare waste (HCW) incineration practices in the global South countries are among the major sources of black carbon (BC) emissions or smoke. This study analyzes HCW incineration trends during emergency situations and smoke from HCW incineration processes in Haiti. The study was prompted by the current arguments about the climate change and the growing health effects associated with BC emissions. The conceptual framework was based on both adverse health effects from BC emissions exposure and climate change potential of BC emissions. Therefore, the goal was to determine whether cardboard HCW sharps containers emit lower BC emissions to the atmosphere during …


A Qualitative Analysis Of Migrant Women Farmworkers' A Qualit Ative Analysis Of Migrant Women Farmworkers’ Perceptions Of Maternal Care Management, Stacey A. Pilling Jan 2015

A Qualitative Analysis Of Migrant Women Farmworkers' A Qualit Ative Analysis Of Migrant Women Farmworkers’ Perceptions Of Maternal Care Management, Stacey A. Pilling

Walden Dissertations and Doctoral Studies

The purpose of this phenomenological study was to examine migrant women farmworkers' views of perinatal care management while working in the fields. Like men, women migrant farmworkers are exposed to many physical, chemical, and biological hazards that pose human health risks. However, women of childbearing age are at an increased risk of having reproductive health difficulties and adverse pregnancy outcomes, and the infant mortality rate among migrant farmworkers is estimated to be twice the national average. Perinatal care is a critical factor in reducing adverse outcomes for perinatal and newborn mortality. Face-to-face interviews were conducted with 15 migrant women farmworkers …


Automated Medication Dispensing Cabinet And Medication Errors, Marie Helen Walsh Jan 2015

Automated Medication Dispensing Cabinet And Medication Errors, Marie Helen Walsh

Walden Dissertations and Doctoral Studies

The number of deaths due to medical errors in hospitals ranges from 44,000 to 98,000 yearly. More than 7,000 of these deaths have taken place due to medication errors. This project evaluated the implementation of an automated medication dispensing cabinet or PYXIS machine in a 25-bed upper Midwestern critical access hospital. Lewin's stage theory of organizational change and Roger's diffusion of innovations theory supported the project. Nursing staff members were asked to complete an anonymous, qualitative survey approximately 1 month after the implementation of the PYXIS and again 1 year later. Questions were focused on the device and its use …


A Meta-Analysis Of Association Between One-Carbon Metabolism Gene Polymorphisms And Risk Of Prostate Cancer, Mahmood Tazari Jan 2015

A Meta-Analysis Of Association Between One-Carbon Metabolism Gene Polymorphisms And Risk Of Prostate Cancer, Mahmood Tazari

Walden Dissertations and Doctoral Studies

Prostate cancer is the most common cancer among men. The purpose of this quantitative, meta-analysis study was to examine one-carbon metabolism gene polymorphisms in a group of genes to determine their association with prostate cancer risk. The genetic epidemiology theory provided the framework for the study. The data collected were from published articles. From over 2,800 individual studies, 20 articles were retained for results and data abstraction, following the title, abstract screen, and full text screening in the second phase. The data were analyzed by a meta-analysis statistical method, combining the results from selected studies to estimate the overall association. …


Diffusion Of Electronic Health Records In Rural Primary Care Clinics, Patricia Lynn Mason Jan 2015

Diffusion Of Electronic Health Records In Rural Primary Care Clinics, Patricia Lynn Mason

Walden Dissertations and Doctoral Studies

By the end of 2015, Medicare-eligible physicians at primary care practices (PCP) who do not use an electronic health record (EHR) system will incur stiff penalties if they fail to meet the deadline for using EHRs. Yet, less than 30% of rural primary clinics have fully functional EHR systems. The purpose of this phenomenology study was to explore rural primary care physicians and physician assistants' experiences regarding overcoming barriers to implementing EHRs. Complex adaptive systems formed the conceptual framework for this study. Data were collected through face-to-face interviews with a purposeful sample of 21 physicians and physician assistants across 2 …


The Distribution Of Type 1 Diabetes Onset In The United States By Demographic Factors, Margaret Beckstrand Jan 2015

The Distribution Of Type 1 Diabetes Onset In The United States By Demographic Factors, Margaret Beckstrand

Walden Dissertations and Doctoral Studies

Type 1 diabetes (T1D) is a chronic and lifelong condition, often diagnosed in childhood. Patients with T1D are at elevated risks of associated health complications, comorbidities, and mortality. Occurrence, clinical presentation, and complications related to T1D differ by age of onset, ethnicity, and gender. The last reported population-based estimates regarding the burden of T1D in children using the National Health and Nutrition Examination Survey (NHANES) were published in 2008, and these estimates were not well stratified by age of onset, ethnicity, and gender. The purpose of this study was to examine these demographics within the conceptual framework of the hygiene …


Regression Analysis Of Cloud Computing Adoption For U.S. Hospitals, Terence H. Lee Jan 2015

Regression Analysis Of Cloud Computing Adoption For U.S. Hospitals, Terence H. Lee

Walden Dissertations and Doctoral Studies

Industrial experts agree that cloud computing can significantly improve business and public access to low cost computing power and storage. Despite the benefits of cloud computing, recent research surveys indicated that its adoption in U.S. hospitals is slower than expected. The purpose of this study was to understand what factors influence cloud adoption in U.S. hospitals. The theoretical foundation of the research was the diffusion of innovations and technology-organization-environment framework. The research question was to examine the predictability of cloud computing adoption for U.S. hospitals as a function of 6 influential factors: relative advantage, compatibility, complexity, organizational size, structure, and …


The Relationship Between Information Technology And Organizational Effectiveness As Perceived By Health Care Providers, Christian Chikwem Ukaga Jan 2015

The Relationship Between Information Technology And Organizational Effectiveness As Perceived By Health Care Providers, Christian Chikwem Ukaga

Walden Dissertations and Doctoral Studies

The U.S. Congress has made health information technology a central component of the national quest to improve health care delivery. The problem addressed in this study was the uncertainty among healthcare providers regarding the benefits of health care information technology adoption relative to healthcare delivery processes and outcomes. The purpose of the study was to understand the effectiveness of information technology as perceived by healthcare providers. The research questions were designed to investigate the relationship between health information technology and organizational effectiveness, exchange of information, organizational process, organizational productivity, and direct personal care. Sociotechnical systems theory and Donabedian's framework for …


Nurses Knowledge, Skills, And Attitude Toward Electronic Health Records (Ehr), Sharon L. Adams Jan 2015

Nurses Knowledge, Skills, And Attitude Toward Electronic Health Records (Ehr), Sharon L. Adams

Walden Dissertations and Doctoral Studies

Information technology (IT) has been rapidly integrated into the healthcare industry, including nursing, and has the ability to reduce errors, cut cost, and enhance patient care. However, approximately 45% of the current nurse workforce lacks adequate training in computer skills, which may hinder the adoption of health-related IT in the workplace. Characteristics of Rogers's diffusion of innovation (relative advantage, compatibility, complexity, trialability, and observability) guided this project. This project was conducted to address the problem of IT adoption on a local level and was designed to assess whether simulation training on a generic electronic health record (EHR) system would improve …


Correlation Analysis Of Climatic Variables, Migration And Dengue Cases In Southeast Florida, Brunilda Lugo Jan 2015

Correlation Analysis Of Climatic Variables, Migration And Dengue Cases In Southeast Florida, Brunilda Lugo

Walden Dissertations and Doctoral Studies

Dengue fever is a debilitating, viral, mosquito-borne disease occurring in tropical and subtropical areas in the world. The majority of dengue cases in the United States were acquired in endemic areas by travelers or immigrants. However, in recent years, autochthonous (locally acquired) dengue cases have been diagnosed in Florida. The purpose of this study was to find an association between potential risk factors and the expansion of dengue fever in the United States. Guided by the eco-bio-social framework, which offers a broad assessment of risk factors for the illness, a retrospective design was used with archival data to correlate changes …


Assessing Clinical Software User Needs For Improved Clinical Decision Support Tools, Kimberly B. Denney Jan 2015

Assessing Clinical Software User Needs For Improved Clinical Decision Support Tools, Kimberly B. Denney

Walden Dissertations and Doctoral Studies

Consolidating patient and clinical data to support better-informed clinical decisions remains a primary function of electronic health records (EHRs). In the United States, nearly 6 million patients receive care from an accountable care organization (ACO). Knowledge of clinical decision support (CDS) tool design for use by physicians participating in ACOs remains limited. The purpose of this quantitative study was to examine whether a significant correlation exists between characteristics of alert content and alert timing (the independent variables) and physician perceptions of improved ACO quality measure adherence during electronic ordering (the dependent variable). Sociotechnical theory supported the theoretical framework for this …


Diffusion Of Technology In Small To Medium Medical Providers In Saudi Arabia, Ziad Hisham Arnaout Jan 2015

Diffusion Of Technology In Small To Medium Medical Providers In Saudi Arabia, Ziad Hisham Arnaout

Walden Dissertations and Doctoral Studies

The Saudi ministry of health reported that government health care spending doubled from 2008 to 2011. To address increased demand, the government encouraged small to medium enterprise (SME) growth. However, SME leaders could not leverage technology as a growth enabler because they lacked strategies to address operating inefficiencies associated with technology. Only 50% of hospitals fully implemented information technology. The purpose of this phenomenological study was to explore lived experiences of SME leaders on strategies needed to accelerate technology implementation. This exploration drew on a conceptual framework developed from Wainwright and Waring's framework addressing issues of technology adoption. Data were …


Multi-Surface Simplex Spine Segmentation For Spine Surgery Simulation And Planning, Rabia Haq Jan 2015

Multi-Surface Simplex Spine Segmentation For Spine Surgery Simulation And Planning, Rabia Haq

Computational Modeling & Simulation Engineering Theses & Dissertations

This research proposes to develop a knowledge-based multi-surface simplex deformable model for segmentation of healthy as well as pathological lumbar spine data. It aims to provide a more accurate and robust segmentation scheme for identification of intervertebral disc pathologies to assist with spine surgery planning. A robust technique that combines multi-surface and shape statistics-aware variants of the deformable simplex model is presented. Statistical shape variation within the dataset has been captured by application of principal component analysis and incorporated during the segmentation process to refine results. In the case where shape statistics hinder detection of the pathological region, user-assistance is …


Risk Based Optimization For Improving Emergency Medical Systems, Sandhya Saisubramanian, Pradeep Varakantham, Hoong Chuin Lau Jan 2015

Risk Based Optimization For Improving Emergency Medical Systems, Sandhya Saisubramanian, Pradeep Varakantham, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

In emergency medical systems, arriving at the incident location a few seconds early can save a human life. Thus, this paper is motivated by the need to reduce the response time – time taken to arrive at the incident location after receiving the emergency call – of Emergency Response Vehicles, ERVs (ex: ambulances, fire rescue vehicles) for as many requests as possible. We expect to achieve this primarily by positioning the "right" number of ERVs at the "right" places and at the "right" times. Given the exponentially large action space (with respect to number of ERVs and their placement) and …


An Appraisal Of Experiences Of Climate Change And Adaptive Response To Heat Stress By Farmers In Rural Ghana, Kwasi Frimpong Jan 2015

An Appraisal Of Experiences Of Climate Change And Adaptive Response To Heat Stress By Farmers In Rural Ghana, Kwasi Frimpong

Theses: Doctorates and Masters

With the increase in average global temperatures, heat-related illnesses and deaths have unfolded as occupational and health issues. Periods of high to extreme temperatures are becoming more common and are a leading cause of weather-related deaths in many countries. In agricultural settings of African countries, heat stress is a major concern as many smallholder farmers work outdoors with limited access to cooling systems even in their resting and living environments. This study, conducted in the Bawku East part of Northern-East Ghana in 2013, examines, in the context of climate change, the trends and impacts of heat stress on smallholder farmers, …


Effects Of Ambient Coarse, Fine, And Ultrafine Particles And Their Biological Constituents On Systemic Biomarkers: A Controlled Human Exposure Study, Ling Liu, Bruce Urch, Raymond Poon, Mieczyslaw Szyszkowicz, Mary Speck, Diane R. Gold, Amanda J. Wheeler, James A. Scott, Jeffrey R. Brook, Peter S. Thorne, Frances S. Silverman Jan 2015

Effects Of Ambient Coarse, Fine, And Ultrafine Particles And Their Biological Constituents On Systemic Biomarkers: A Controlled Human Exposure Study, Ling Liu, Bruce Urch, Raymond Poon, Mieczyslaw Szyszkowicz, Mary Speck, Diane R. Gold, Amanda J. Wheeler, James A. Scott, Jeffrey R. Brook, Peter S. Thorne, Frances S. Silverman

Research outputs 2014 to 2021

Background: Ambient coarse, fine, and ultrafine particles have been associated with mortality and morbidity. Few studies have compared how various particle size fractions affect systemic biomarkers. Objectives: We examined changes of blood and urinary biomarkers following exposures to three particle sizes. Methods: Fifty healthy nonsmoking volunteers, mean age of 28 years, were exposed to coarse (2.5–10 μm; mean, 213 μg/m3) and fine (0.15–2.5 μm; mean, 238 μg/m3) concentrated ambient particles (CAPs), and filtered ambient and/or medical air. Twenty-five participants were exposed to ultrafine CAP (< 0.3 μm; mean, 136 μg/m3) and filtered medical air. Exposures lasted 130 min, separated by ≥ 2 weeks. Blood/urine samples were collected preexposure and 1 hr and 21 hr postexposure to determine blood interleukin-6 and C-reactive protein (inflammation), endothelin-1 and vascular endothelial growth factor (VEGF; vascular mediators), and malondialdehyde (lipid peroxidation); as well as urinary VEGF, 8-hydroxy-deoxy-guanosine (DNA oxidation), and malondialdehyde. Mixed-model regressions assessed pre- and postexposure differences. results: One hour postexposure, for every 100-μg/m3 increase, coarse CAP was associated with increased blood VEGF (2.41 pg/mL; 95% CI: 0.41, 4.40) in models adjusted for O3, fine CAP with increased urinary malondialdehyde in single- (0.31 nmol/mg creatinine; 95% CI: 0.02, 0.60) and two-pollutant models, and ultrafine CAP with increased urinary 8-hydroxydeoxyguanosine in single- (0.69 ng/mg creatinine; 95% CI: 0.09, 1.29) and two-pollutant models, lasting < 21 hr. Endotoxin was significantly associated with biomarker changes similar to those found with CAPs. conclusions: Ambient particles with various sizes/constituents may influence systemic biomarkers differently. Endotoxin in ambient particles may contribute to vascular mediator changes and oxidative stress.


Investigation Of Interferences And Development Of Pre-Treatment Methods For Arsenic Analysis By Anodic Stripping Voltammetry, Paul Lewtas Jan 2015

Investigation Of Interferences And Development Of Pre-Treatment Methods For Arsenic Analysis By Anodic Stripping Voltammetry, Paul Lewtas

Theses: Doctorates and Masters

Contamination of drinking water is a serious health issue in many developing countries and there is a recognised need for low cost portable systems that are capable of analysing drinking water down to low ppb levels. Anodic Stripping Voltammetry (ASV) instruments meet these requirements but suffer interferences from other species which may also be present in the sample, particularly organics, other metals and sulfides. The last of these has received surprisingly little attention in the literature, despite being a proven interferent.

This study investigates the impact of each of these interference types, as well as a number of traditional and …