Diffusing Wave Spectroscopy Measurements of Colloidal Suspension Dynamics.

Diffusing wave spectroscopy (DWS) is used to measure the dynamics of charged silica particles between the volume fractions 0.065 ≤ ϕ ≤ 0.352 (weight percentages from 12.7 to 55.8 wt %). The short-time diffusivity averaged over the scattering vectors sampled by DWS D¯(ϕ) decreases with an increasing concentration. An effective hard-sphere model that accounts for hydrodynamic interactions and a double-layer repulsion fits the values up to an effective volume fraction ϕeff=ϕb^3≈0.6, where b^ is the excluded shell radius normalized by the particle radius b^ = b/a = 1.3. While DWS measurements of diffusivity are sensitive to repulsive interactions, we show that they are relatively insensitive to attraction, such as those due to secondary minima in the interaction potential or weak depletion interaction.

The Effect of 30-Day Adequate Transitions of Acute Stroke Care on 90-Day Readmission or Death.

OBJECTIVES: We explore patient-reported behaviors and activities within 30-days post-stroke hospitalization and their role in reducing death or readmissions within 90-days post-stroke. METHODS: We constructed the adequate transitions of care (ATOC) composite score, measuring patient-reported participation in eligible behaviors and activities (diet modification, weekly exercise, follow-up medical appointment attendance, medication adherence, therapy use, and toxic habit cessation) within 30 days post-stroke hospital discharge. We analyzed ATOC scores in ischemic and intracerebral hemorrhage stroke patients discharged from the hospital to home or rehabilitation facilities and enrolled in the NIH-funded Transitions of Care Stroke Disparities Study (TCSD-S). We utilized Cox regression analysis, with the progressive adjustment for sociodemographic variables, social determinants of health, and stroke risk factors, to determine the associations between ATOC score within 30-days and death or readmission within 90-days post-stroke. RESULTS: In our sample of 1239 stroke patients (mean age 64+/-14, 58% male, 22% Hispanic, 22% Black, 52% White, 76% discharged home), 13% experienced a readmission or death within 90 days (3 deaths, 160 readmissions, 3 readmissions with subsequent death). Seventy percent of participants accomplished a ≥75% ATOC score. A 25% increase in ATOC was associated with a respective 20% (95% CI 3%-33%) reduced risk of death or readmission within 90-days. CONCLUSION: ATOC represents modifiable behaviors and activities within 30-days post-stroke that are associated with reduced risk of death or readmission within 90-days post-stroke. The ATOC score should be validated in other populations, but it can serve as a tool for improving transitions of stroke care initiatives and interventions.

Microstructure of continuous shear thickening colloidal suspensions determined by rheo-VSANS and rheo-USANS.

Research on shear thickening colloidal suspensions demonstrates that measurements of the microstructure can elucidate the source of the rheological material properties in the shear thickened state as well as critically test simulations and theory based on a variety of mechanisms such as enhanced lubrication hydrodynamics, elastohydrodynamics, and contact friction. Prior work on continuous shear thickening dispersions with a well-defined shear thickened state identified the formation of hydroclusters as characteristic of this state, determined the anisotropy in the nearest neighbor distribution, and used this information to test prevailing theories and simulations. However, important questions remain about the mesoscale (i.e., particle cluster scale) microstructure of the shear thickened state. Here we employ neutron scattering methods applied to shearing colloidal dispersions of spherical particles with two extremes of friction and lubrication surface properties to resolve the longer-length scale microstructure in the shear thickened state. Hydroclusters are shown to be highly localized, in agreement with prior neutron scattering and direct optical measurements, but in disagreement with the most recent simulations that predict a longer-range structure formation. These results combined with prior measurements provide experimental evidence about the length scale of microstructure formation in continuous shear thickening suspensions necessary to improve our understanding of the phenomenon as well as guide theoretical investigations that quantitatively link nanoscale forces to macroscopic properties in the shear thickened state.

Neighbourhood greenness and depression among older adults.

BACKGROUND: Neighbourhood greenness or vegetative presence has been associated with indicators of health and well-being, but its relationship to depression in older adults has been less studied. Understanding the role of environmental factors in depression may inform and complement traditional depression interventions, including both prevention and treatment.AimsThis study examines the relationship between neighbourhood greenness and depression diagnoses among older adults in Miami-Dade County, Florida, USA. METHOD: Analyses examined 249 405 beneficiaries enrolled in Medicare, a USA federal health insurance programme for older adults. Participants were 65 years and older, living in the same Miami location across 2 years (2010-2011). Multilevel analyses assessed the relationship between neighbourhood greenness, assessed by average block-level normalised difference vegetative index via satellite imagery, and depression diagnosis using USA Medicare claims data. Covariates were individual age, gender, race/ethnicity, number of comorbid health conditions and neighbourhood median household income. RESULTS: Over 9% of beneficiaries had a depression diagnosis. Higher levels of greenness were associated with lower odds of depression, even after adjusting for demographics and health comorbidities. When compared with individuals residing in the lowest tertile of greenness, individuals from the middle tertile (medium greenness) had 8% lower odds of depression (odds ratio 0.92; 95% CI 0.88, 0.96; P = 0.0004) and those from the high tertile (high greenness) had 16% lower odds of depression (odds ratio 0.84; 95% CI 0.79, 0.88; P < 0.0001). CONCLUSIONS: Higher levels of greenness may reduce depression odds among older adults. Increasing greenery - even to moderate levels - may enhance individual-level approaches to promoting wellness.Declaration of interestNone.

Accreditation Status and Geographic Location of Outpatient Echocardiographic Testing Facilities Among Medicare Beneficiaries: The VALUE-ECHO Study.

OBJECTIVES: Accreditation of echocardiographic testing facilities by the Intersocietal Accreditation Commission (IAC) is supported by the American College of Cardiology and American Society of Echocardiography. However, limited information exists on the accreditation status and geographic distribution of echocardiographic facilities in the United States. Our study aimed to identify (1) the proportion of outpatient echocardiography facilities used by Medicare beneficiaries that are IAC accredited, (2) their geographic distribution, and (3) variations in procedure type and volume by accreditation status. METHODS: As part of the VALUE-ECHO (Value of Accreditation, Location, and Utilization Evaluation-Echocardiography) study, we examined the proportion of IAC-accredited echocardiographic facilities performing outpatient echocardiography in the 2013 Centers for Medicare and Medicaid Services outpatient limited data set (100% sample) and their geographic distribution using geocoding in ArcGIS (ESRI, Redlands, CA). RESULTS: Among 4573 outpatient facilities billing Medicare for echocardiographic testing in 2013, 99.6% (n = 4554) were IAC accredited (99.7% in the 50 US states and 86.2% in Puerto Rico). The proportion IAC-accredited echocardiographic facilities varied by region, with 98.7%, 99.9%, 99.9%, 99.5%, and 86.2% of facilities accredited in the Northeast, South, Midwest, West, and Puerto Rico, respectively (P < .01, Fisher exact test). Of all echocardiographic outpatient procedures conducted (n = 1,890,156), 99.8% (n = 1,885,382) were performed in IAC-accredited echocardiographic facilities. Most procedures (90.9%) were transthoracic echocardiograms, of which 99.7% were conducted in IAC-accredited echocardiographic facilities. CONCLUSIONS: Almost all outpatient echocardiographic facilities billed by Medicare are IAC accredited. This accreditation rate is substantially higher than previously reported for US outpatient vascular testing facilities (13% IAC accredited). The uniformity of imaging and interpretation protocols from a single accrediting body is important to facilitate optimal cardiovascular care.

Intersocietal Accreditation Commission Accreditation Status of Outpatient Cerebrovascular Testing Facilities Among Medicare Beneficiaries: The VALUE Study.

OBJECTIVES: Accreditation of cerebrovascular ultrasound laboratories by the Intersocietal Accreditation Commission (IAC) and equivalent organizations is supported by the Joint Commission certification of stroke centers. Limited information exists on the accreditation status and geographic distribution of cerebrovascular testing facilities in the United States. Our study objectives were to identify the proportion of IAC-accredited outpatient cerebrovascular testing facilities used by Medicare beneficiaries, describe their geographic distribution, and identify variations in cerebrovascular testing procedure types and volumes by accreditation status. METHODS: As part of the VALUE (Vascular Accreditation, Location, and Utilization Evaluation) Study, we examined the proportion of IAC-accredited facilities that conducted cerebrovascular testing in a 5% Centers for Medicare and Medicaid Services random Outpatient Limited Data Set in 2011 and investigated their geographic distribution using geocoding. RESULTS: Among 7327 outpatient facilities billing Medicare for cerebrovascular testing, only 22% (1640) were IAC accredited. The proportion of IAC-accredited cerebrovascular testing facilities varied by region (χ(2)[3] = 177.1; P < .0001), with 29%, 15%, 13%, and 10% located in the Northeast, South, Midwest, and West, respectively. However, of the total number of cerebrovascular outpatient procedures conducted in 2011 (38,555), 40% (15,410) were conducted in IAC-accredited facilities. Most cerebrovascular testing procedures were carotid duplex, with 40% of them conducted in IAC-accredited facilities. CONCLUSIONS: The proportion of facilities conducting outpatient cerebrovascular testing accredited by the IAC is low and varies by region. The growing number of certified stroke centers should be accompanied by more accredited outpatient vascular testing facilities, which could potentially improve the quality of stroke care.

Accreditation status and geographic location of outpatient vascular testing facilities among Medicare beneficiaries: the VALUE (Vascular Accreditation, Location & Utilization Evaluation) study.

OBJECTIVE: There is limited information on the accreditation status and geographic distribution of vascular testing facilities in the US. The Centers for Medicare & Medicaid Services (CMS) provide reimbursement to facilities regardless of accreditation status. The aims were to: (1) identify the proportion of Intersocietal Accreditation Commission (IAC) accredited vascular testing facilities in a 5% random national sample of Medicare beneficiaries receiving outpatient vascular testing services; (2) describe the geographic distribution of these facilities. METHODS: The VALUE (Vascular Accreditation, Location & Utilization Evaluation) Study examines the proportion of IAC accredited facilities providing vascular testing procedures nationally, and the geographic distribution and utilization of these facilities. The data set containing all facilities that billed Medicare for outpatient vascular testing services in 2011 (5% CMS Outpatient Limited Data Set (LDS) file) was examined, and locations of outpatient vascular testing facilities were obtained from the 2011 CMS/Medicare Provider of Services (POS) file. RESULTS: Of 13,462 total vascular testing facilities billing Medicare for vascular testing procedures in a 5% random Outpatient LDS for the US in 2011, 13% (n=1730) of facilities were IAC accredited. The percentage of IAC accredited vascular testing facilities in the LDS file varied significantly by US region, p<0.0001: 26%, 12%, 11%, and 7% for the Northeast, South, Midwest, and Western regions, respectively. CONCLUSIONS: Findings suggest that the proportion of outpatient vascular testing facilities that are IAC accredited is low and varies by region. Increasing the number of accredited vascular testing facilities to improve test quality is a hypothesis that should be tested in future research.

Particle size distributions by transmission electron microscopy: an interlaboratory comparison case study.

This paper reports an interlaboratory comparison that evaluated a protocol for measuring and analysing the particle size distribution of discrete, metallic, spheroidal nanoparticles using transmission electron microscopy (TEM). The study was focused on automated image capture and automated particle analysis. NIST RM8012 gold nanoparticles (30 nm nominal diameter) were measured for area-equivalent diameter distributions by eight laboratories. Statistical analysis was used to (1) assess the data quality without using size distribution reference models, (2) determine reference model parameters for different size distribution reference models and non-linear regression fitting methods and (3) assess the measurement uncertainty of a size distribution parameter by using its coefficient of variation. The interlaboratory area-equivalent diameter mean, 27.6 nm ± 2.4 nm (computed based on a normal distribution), was quite similar to the area-equivalent diameter, 27.6 nm, assigned to NIST RM8012. The lognormal reference model was the preferred choice for these particle size distributions as, for all laboratories, its parameters had lower relative standard errors (RSEs) than the other size distribution reference models tested (normal, Weibull and Rosin-Rammler-Bennett). The RSEs for the fitted standard deviations were two orders of magnitude higher than those for the fitted means, suggesting that most of the parameter estimate errors were associated with estimating the breadth of the distributions. The coefficients of variation for the interlaboratory statistics also confirmed the lognormal reference model as the preferred choice. From quasi-linear plots, the typical range for good fits between the model and cumulative number-based distributions was 1.9 fitted standard deviations less than the mean to 2.3 fitted standard deviations above the mean. Automated image capture, automated particle analysis and statistical evaluation of the data and fitting coefficients provide a framework for assessing nanoparticle size distributions using TEM for image acquisition.

Diagnosis and treatment patterns of Peyronie's disease among different racial, ethnic, and regional groups in the Veterans Affairs healthcare system.

Peyronie's Disease, which is known to have racial/ethnic disparities in the general population, has never been studied in the veteran population. We compared the diagnosis and treatment rates for Peyronie's Disease among United States veterans of various racial-ethnic backgrounds at Veterans Affairs medical centers, which are equal-access systems. We queried the Veterans Affair Informatics and Computing Infrastructure to identify 17,647 Peyronie's Disease patients in the United States by ICD-9 or ICD-10 code between 2015-2020. We assessed demographic characteristics, clinical characteristics, Veterans Affairs facility information, and treatment patterns. Racial-ethnic demographics of veterans with Peyronie's Disease were 71.4% White, 15.4% Black, 5.8% Hispanic, 1.6% Native American, 0.3% Asian, and 5.4% unknown. Treatment rate was 13.6% overall, 13.6% of Whites (ref), 14.3% of Blacks (p = 0.2985), 13.5% of Hispanics (p = 0.9205), 9.1% of Asians (p = 0.3319), 16.7% of Native Americans (p = 0.1406), and 9.6% of unknown (p = 0.0041). White patients were more likely to receive injectional therapy and less likely to undergo surgery than Black patients. Peyronie's Disease patients at Veterans Affairs facilities are treated at the same rate, indicating that equal-access healthcare systems may mitigate racial-ethnic disparities. Further research is necessary to account for differences in disease severity and Veterans Affairs surgeon availability.

Neighborhood Environment and Metabolic Risk in Hispanics/Latinos From the Hispanic Community Health Study/Study of Latinos.

INTRODUCTION: This study examines the associations of neighborhood environments with BMI, HbA1c, and diabetes across 6 years in Hispanic/Latino adults. METHODS: Participants from the Hispanic Community Health Study/Study of Latinos San Diego site (n=3,851, mean age=39.4 years, 53.3% women, 94.0% Mexican heritage) underwent assessment of metabolic risk factors and diabetes status (categorized as normoglycemia, prediabetes, and diabetes) at baseline (2008-2011) and approximately 6 years later (2014-2017). In the Study of Latinos Community and Surrounding Areas Study ancillary study (2015-2020), participant baseline addresses were geocoded, and neighborhoods were defined using 800-meter circular buffers. Neighborhood variables representing socioeconomic deprivation, residential stability, social disorder, walkability, and greenness were created using Census and other public databases. Analyses were conducted in 2020-2021. RESULTS: Complex survey regression analyses revealed that greater neighborhood socioeconomic deprivation was associated with higher BMI (ß=0.14, p<0.001) and HbA1c (ß=0.08, p<0.01) levels and a higher odds of worse diabetes status (i.e., having prediabetes versus normoglycemia and having diabetes versus prediabetes; OR=1.25, 95% CI=1.06, 1.47) at baseline. Greater baseline neighborhood deprivation also was related to increasing BMI (ß=0.05, p<0.01) and worsening diabetes (OR=1.27, 95% CI=1.10, 1.46) statuses, whereas social disorder was related to increasing BMI levels (ß=0.05, p<0.05) at Visit 2. There were no associations of expected protective factors of walkability, greenness, or residential stability. CONCLUSIONS: Neighborhood deprivation and disorder were related to worse metabolic health in San Diego Hispanic/Latino adults of mostly Mexican heritage. Multilevel interventions emphasizing individual and structural determinants may be most effective in improving metabolic health among Hispanic/Latino individuals.

The promise of nanotechnology for solving clinical problems in breast cancer.

Approaches for breast cancer treatment are invasive, disfiguring, have significant side-effects, and are not always curative. Nanotechnology is an emerging area which is focused on engineering of materials <100 × 10(-9) m. There is significant promise for advancing nanotechnology to improve breast cancer diagnosis and treatment including non-invasive therapy, monitoring response to therapy, advanced imaging, treatment of metastatic disease, and improved nodal staging. Current approaches and important future directions are discussed.

Nanoparticles as contrast agents for in-vivo bioimaging: current status and future perspectives.

Nanoparticle-based contrast agents are quickly becoming valuable and potentially transformative tools for enhancing medical diagnostics for a wide range of in-vivo imaging modalities. Compared with conventional molecular-scale contrast agents, nanoparticles (NPs) promise improved abilities for in-vivo detection and potentially enhanced targeting efficiencies through longer engineered circulation times, designed clearance pathways, and multimeric binding capacities. However, NP contrast agents are not without issues. Difficulties in minimizing batch-to-batch variations and problems with identifying and characterizing key physicochemical properties that define the in-vivo fate and transport of NPs are significant barriers to the introduction of new NP materials as clinical contrast agents. This manuscript reviews the development and application of nanoparticles and their future potential to advance current and emerging clinical bioimaging techniques. A focus is placed on the application of solid, phase-separated materials, for example metals and metal oxides, and their specific application as contrast agents for in-vivo near-infrared fluorescence (NIRF) imaging, magnetic resonance imaging (MRI), positron emission tomography (PET), computed tomography (CT), ultrasound (US), and photoacoustic imaging (PAI). Clinical and preclinical applications of NPs are identified for a broad spectrum of imaging applications, with commentaries on the future promise of these materials. Emerging technologies, for example multifunctional and theranostic NPs, and their potential for clinical advances are also discussed.

The 'Gator' Mouse Suit for early bioluminescent metastatic breast cancer detection and nanomaterial signal enhancement during live animal imaging.

UNLABELLED: Optical imaging is a cornerstone of modern oncologic research. The aim of this study is to determine the value of a new tool to enhance bioluminescent and fluorescent sensitivity for facilitating very-low-level signal detection in vivo. EXPERIMENTAL: For bioluminescent imaging experiments, a luciferase expressing breast cancer cell line with metastatic phenotype was implanted orthotopically into the mammary fat pad of mice. For fluorescent imaging experiments, near-infrared (NIR) nanoparticles were injected intratumorally and subcutaneously into mice. Images were compared in mice with and without application of the 'Gator' Mouse Suit (GMS). RESULTS: The GMS was associated with early detection and quantification of metastatic bioluminescent very-low-level signal not possible with conventional imaging strategies. Similarly, NIR nanoparticles that were undetectable in locations beyond the primary injection site could be visualized and their very-low-level signal quantifiable with the aid of the GMS. CONCLUSION: The GMS is a device which has tremendous potential for facilitating the development of bioluminescent models and fluorescent nanomaterials for translational oncologic applications.

Relationship of Neighborhood Greenness to Alzheimer's Disease and Non-Alzheimer's Dementia Among 249,405 U.S. Medicare Beneficiaries.

BACKGROUND: Neighborhood greenness (vegetative presence) has been linked to multiple health outcomes, but its relationship to Alzheimer's disease (AD) and non-Alzheimer's (non-AD) dementia has been less studied. OBJECTIVE: This study examines the relationship of greenness to both AD and non-AD dementia in a population-based sample of Medicare beneficiaries. METHODS: Participants were 249,405 US Medicare beneficiaries aged > 65 years living in Miami-Dade County, FL, from 2010 to 2011. Multi-level analyses examined the relationship of greenness, assessed by mean Census block level Normalized Difference Vegetation Index (NDVI), to odds of each of AD, Alzheimer's disease and related dementias (ADRD), and non-AD dementia, respectively. Covariates included age, gender, race/ethnicity, number of comorbid health conditions, and neighborhood income. RESULTS: Higher greenness was associated with reduced risk of AD, ADRD, and non-AD dementia, respectively, adjusting for individual and neighborhood sociodemographics. Compared to the lowest greenness tertile, the highest greenness tertile was associated with reduced odds of AD by 20%(odds ratio, 0.80; 95%CI, 0.75-0.85), ADRD by 18%(odds ratio, 0.82; 95%CI, 0.77-0.86), and non-AD dementia by 11%(odds ratio, 0.89; 95%CI, 0.82-0.96). After further adjusting for number of comorbidities, compared to the lowest greenness tertile, the highest greenness tertile was associated with reduced odds of AD (OR, 0.94; 95%CI, 0.88-1.00) and ADRD (OR, 0.93; 95%CI, 0.88-0.99), but not non-AD dementia (OR, 1.01; 95%CI, 0.93-1.08). CONCLUSION: High neighborhood greenness may be associated with lower odds of AD and ADRD. Environmental improvements, such as increasing neighborhood vegetation, may be a strategy to reduce risk for AD and possibly other dementias.

The relationship between depressive symptoms and walking among Hispanic older adults: a longitudinal, cross-lagged panel analysis.

OBJECTIVES: This study examines the relationship between depressive symptoms and walking behavior across 30 months in a prospective study of 217 community-dwelling, Hispanic older adults in Miami, Florida (ages 70-100 years). METHOD: Analyses examine the direction of the relationship between depressive symptoms and physical activity (i.e., walking) over time, as well as test for a potential bi-directional or reciprocal relationship between these two variables. RESULTS: Structural equation modeling (SEM) with a cross-lagged panel design revealed that walking was unrelated to subsequent depressive symptoms. However, depressive symptoms were related to subsequent walking behavior at every time-point, such that higher levels of depressive symptoms were predictive of less walking in the future. Older adults who had clinically-relevant depressive symptoms at the initial assessment had 1.34 times the risk of not walking 30 months later, compared to older adults without clinically-relevant depressive symptoms. CONCLUSION: Results support the need for primary care providers to evaluate and address depressive symptoms among older adults, as a means of reducing sedentary behavior and potentially improving health. Further research on the prevention and management of depressive symptoms and sedentary behavior is needed, given the morbidity related to both of these health risks, particularly for minority and low-socio-economic status (SES) older adults.

The relationship of neighborhood climate to perceived social support and mental health in older Hispanic immigrants in Miami, Florida.

OBJECTIVE: This study examines the relationship of neighborhood climate (i.e., neighborhood social environment) to perceived social support and mental health outcomes in older Hispanic immigrants. METHOD: A population-based sample of 273 community-dwelling older Hispanic immigrants (aged 70 to 100) in Miami, Florida, completed self-report measures of neighborhood climate, social support, and psychological distress and performance-based measures of cognitive functioning. Structural equation modeling was used to model the relationship of neighborhood climate to elders' perceived social support and mental health outcomes (i.e., cognitive functioning, psychological distress). RESULTS: Neighborhood climate had a significant direct relationship to cognitive functioning, after controlling for demographics. By contrast, neighborhood climate had a significant indirect relationship to psychological distress, through its relationship to perceived social support. Moreover, social support mediated the relationship between neighborhood climate and psychological distress. DISCUSSION: Findings suggest that a more positive neighborhood social environment may be associated with better mental health outcomes in urban, older Hispanic immigrants.

What is the impact of surface modifications and particle size on commercial titanium dioxide particle samples? - A review of in vivo pulmonary and oral toxicity studies - Revised 11-6-2018.

There is an ongoing discussion on the influence of surface-modifications on the toxicity of commercial particulate materials and how alterations in physical-chemical properties of surfaces impact toxicity. Titanium dioxide (TiO2) is a poorly soluble particulate material of significant socioeconomic importance that largely exists as surface-modified particle-types in commerce. The observed toxicological effects of TiO2 are primarily due to particle effects rather than substance chemistry, as such TiO2 is commonly considered to be a poorly soluble low toxicity (PSLT) particle. This review provides an overview of the effect of surface modifications on the pulmonary and oral toxicity of commercial TiO2 particles with emphasis on in vivo studies with appropriate controls, and where both surface modified and untreated materials are present in the same study. Published literature findings involving pulmonary and oral exposures to surface modified TiO2 particles were reviewed and evaluated for quality and commercial relevance. Suitable publications involving animal studies were identified and summarized. Several studies were identified that have evaluated commercially-relevant surface-modified forms of titanium dioxide with appropriate data quality and with direct comparison to untreated counterparts. Hydrophilic inorganic surface modifications including silica, alumina/alumina hydroxide depositions have been tested along with common hydrophilic and hydrophobic-organic surface treatments. The results for both pigmentary and nanoscale materials demonstrate similar behaviour and indicate limited impact of particle size, surface chemistry, surface charge and surface wettability on observed pulmonary or oral toxicity effects. The low intrinsic toxicity of the TiO2 base particle and evaluated surface modifications may account for the observed outcomes. A few published studies have drawn different conclusions; however, these were either not conducted using commercial TiO2 samples (with surface coatings), had several confounding variables to investigate, or were carried out using mouse strains. The differences in experimental designs are described. The identified pulmonary and oral toxicity studies largely indicate that surface modifications and particle size alone have little or no impact on the lung toxicity of TiO2 particles, following pulmonary exposures when all constituent materials are comprised of chemicals of low specific toxicity particles. In addition, based upon the results of 2 oral toxicity studies, one with surface treated TiO2 particles (OECD 408) and one without surface treated (OECD 407) TiO2 particles, there appears to have been no adverse impact on toxicity with the surface-coated material, as both studies produced no adverse effects at the very high doses tested.

Relationship of Neighborhood Greenness to Heart Disease in 249 405 US Medicare Beneficiaries.

Background Nature exposures may be associated with reduced risk of heart disease. The present study examines the relationship between objective measures of neighborhood greenness (vegetative presence) and 4 heart disease diagnoses (acute myocardial infarction, ischemic heart disease, heart failure, and atrial fibrillation) in a population-based sample of Medicare beneficiaries. Methods and Results The sample included 249 405 Medicare beneficiaries aged 65 years and older whose location ( ZIP +4) in Miami-Dade County, Florida, did not change from 2010 to 2011. Analyses examined relationships between greenness, measured by mean block-level normalized difference vegetation index from satellite imagery, and 4 heart disease diagnoses. Hierarchical regression analyses, in a multilevel framework, assessed the relationship of greenness to each heart disease diagnosis, adjusting successively for individual sociodemographics, neighborhood income, and biological risk factors (diabetes mellitus, hypertension, and hyperlipidemia). Higher greenness was associated with reduced heart disease risk, adjusting for individual sociodemographics and neighborhood income. Compared with the lowest tertile of greenness, the highest tertile of greenness was associated with reduced odds of acute myocardial infarction by 25% (odds ratio, 0.75; 95% CI , 0.63-0.90), ischemic heart disease by 20% (odds ratio, 0.80; 95% CI , 0.77-0.83), heart failure by 16% (odds ratio, 0.84; 95% CI , 0.80-0.88), and atrial fibrillation by 6% (odds ratio, 0.94; 95% CI , 0.87-1.00). Associations were attenuated after adjusting for biological risk factors, suggesting that cardiometabolic risk factors may partly mediate the greenness to heart disease relationships. Conclusions Neighborhood greenness may be associated with reduced heart disease risk. Strategies to increase area greenness may be a future means of reducing heart disease at the population level.

Built environment and physical functioning in Hispanic elders: the role of "eyes on the street".

BACKGROUND: Research on neighborhood effects increasingly includes the influences of the built environment on health and social well-being. OBJECTIVES: In this population-based study in a low-socioeconomic-status (SES), Hispanic neighborhood, we examined whether architectural features of the built environment theorized to promote direct observations and interactions (e.g., porches, stoops) predicted Hispanic elders' social support and psychological and physical functioning. METHODS: We coded built-environment features for all 3,857 lots in the 403-block area of an urban Miami, Florida, community. We then conducted three annual assessments of social support, psychological distress, and physical functioning in a population-based sample of 273 low-SES Hispanic elders (70-100 years of age). We used structural equation modeling analytic techniques to examine hypothesized relationships between the built environment and elders' social support, psychological distress, and physical functioning over a 3-year period. RESULTS: After controlling for age, sex, and income, architectural features of the built environment theorized to facilitate visual and social contact had a significant direct relationship with elders' physical functioning as measured 3 years later, and an indirect relationship through social support and psychological distress. Further binomial regression analyses suggested that elders living on blocks marked by low levels of positive front entrance features were 2.7 times as likely to have subsequent poor levels of physical functioning, compared with elders living on blocks with a greater number of positive front entrance features [b = 0.99; chi(2) (1 df) = 3.71; p = 0.05; 95% confidence interval, 1.0-7.3]. CONCLUSIONS: Architectural features that facilitate visual and social contacts may be a protective factor for elders' physical functioning.

Longitudinal relationships between cognitive functioning and depressive symptoms among Hispanic older adults.

This study examines the relationship between cognitive functioning and depressive symptoms across 3 years in a prospective study of 273 community-dwelling, Hispanic older adults in Miami. The analyses extend the literature by testing for a bidirectional or reciprocal relationship between depressive symptoms and cognitive functioning over time and by examining the relationship between these variables among Hispanics, an understudied population at risk of developing depressive symptoms and cognitive impairments. Structural equation modeling with a cross-lagged panel design showed that depressive symptoms were unrelated to subsequent cognitive functioning. However, cognitive functioning was related to subsequent depressive symptoms at every time point, such that poorer cognitive functioning was related to higher depressive symptoms. Findings suggest that cognitive declines may predict depressive symptoms in community-dwelling Hispanic older adults.