513 research outputs found
A laboratory scale model technique for investigating pneumatic tire hydroplaning
Laboratory scale model technique for investigating pneumatic tire hydroplanin
Multiple morbidities in companion dogs: a novel model for investigating age-related disease
The proportion of men and women surviving over 65 years has been steadily increasing over the last century. In their later years, many of these individuals are afflicted with multiple chronic conditions, placing increasing pressure on healthcare systems. The accumulation of multiple health problems with advanced age is well documented, yet the causes are poorly understood. Animal models have long been employed in attempts to elucidate these complex mechanisms with limited success. Recently, the domestic dog has been proposed as a promising model of human aging for several reasons. Mean lifespan shows twofold variation across dog breeds. In addition, dogs closely share the environments of their owners, and substantial veterinary resources are dedicated to comprehensive diagnosis of conditions in dogs. However, while dogs are therefore useful for studying multimorbidity, little is known about how aging influences the accumulation of multiple concurrent disease conditions across dog breeds. The current study examines how age, body weight, and breed contribute to variation in multimorbidity in over 2,000 companion dogs visiting private veterinary clinics in England. In common with humans, we find that the number of diagnoses increases significantly with age in dogs. However, we find no significant weight or breed effects on morbidity number. This surprising result reveals that while breeds may vary in their average longevity and causes of death, their age-related trajectories of morbidities differ little, suggesting that age of onset of disease may be the source of variation in lifespan across breeds. Future studies with increased sample sizes and longitudinal monitoring may help us discern more breed-specific patterns in morbidity. Overall, the large increase in multimorbidity seen with age in dogs mirrors that seen in humans and lends even more credence to the value of companion dogs as models for human morbidity and mortality
CARE COORDINATION, QUALITY AND OUTCOMES: A STUDY IN OLDER ADULTS WITH MULTIPLE CHRONIC CONDITIONS
Background: Care coordination may be most effective in older adults with multiple chronic conditions because they see multiple primary care and specialist physicians, which may complicate efforts to coordinate care for their conditions. There is little evidence on how to best measure and improve care coordination in this population.
Objective: The objective of this thesis is to better understand care coordination in older adults with multiple chronic conditions. The first study examines how to measure care coordination. The second study examines the relationship of care coordination with quality of care processes and patient rating of care. The third study whether one dimension, continuity of care, is associated with subsequent emergency department utilization, and hospital utilization.
Study Design: This is an observational study. All analyses were conducted in a sample of 1,600 adults 65 years of age and older with multiple chronic conditions selected to participate in a patient survey. All subjects were enrolled in a Medicare Advantage Special Needs Plan living in Alabama, Georgia, Missouri, South Carolina, and Texas.
Results: The first study identifies three underlying domains of care coordination: continuity of care, informational continuity between clinicians, and information flow to the patient. The second study finds that patient reported experiences of informational continuity are strongly related to the patient related to the patient’s rating of care, but not related to other measures of technical care quality. The third study finds that higher levels continuity of care is associated with lower odds of a preventable hospitalization in patients with five or fewer conditions but continuity of care is not related to better outcomes in patients with six or more conditions.
Conclusion: Care coordination is a multidimensional construct. Evaluations of care coordination programs should consider using both claims-based and patient survey measures in order to comprehensively assess care coordination programs. Medicare and health plans should consider incentivize informational continuity between clinicians to improve patient rating of care
Relationship between continuity of care and adverse outcomes varies by number of chronic conditions among older adults with diabetes
Background: Continuity of care is a basic tenant of primary care practice. However, the evidence on the importance of continuity of care for older adults with complex conditions is mixed. Objective: To assess the relationship between measurement of continuity of care, number of chronic conditions, and health outcomes. Design: We analyzed data from a cohort of 1,600 US older adults with diabetes and ≥1 other chronic condition in a private Medicare health plan from July 2010 to December 2011. Multivariate regression models were used to examine the association of baseline continuity (the first 6 months) and the composite outcome of any emergency room use or inpatient hospitalization occurring in the following 12-month period. Results: After adjusting for baseline covariates, high known provider continuity (KPC) was associated with an 84% (adjusted odds ratio 0.16; 95% confidence interval 0.09–0.26) reduction in the risk of the composite outcome. High KPC was significantly associated with a lower risk of the composite outcome among individuals with ≥6 conditions. However, the usual provider of care and continuity of care indices were not significantly related with the composite outcome in the overall sample or in those with ≥6 conditions. Conclusion: The relationship between continuity of care and adverse outcomes depends on the measure of continuity of care employed. High morbidity patients are more likely to benefit from continuity of care interventions as measured by the KPC, which measures the proportion of a patient’s visits that are with the same providers over time. Journal of Comorbidity 2016;6(2):65–7
Prediction of stillbirth from biochemical and biophysical markers at 11-13 weeks
Objectives: To develop a model for prediction of stillbirth based on a combination of maternal characteristics and medical history with first trimester biochemical and biophysical markers and evaluate the performance of screening of this model for all stillbirths and those due to impaired placentation and unexplained causes.
Methods: This was a prospective screening study of 76,897 singleton pregnancies including 76,629 live births and 268 (0.35%) antepartum stillbirths; 157 (59%) were secondary to impaired placentation and 111 (41%) were due to other or unexplained causes. Multivariate logistic regression analysis was used to determine if there was a significant contribution to prediction of stillbirth from the maternal factor-derived a priori risk, fetal nuchal translucency thickness (NT), ductus venosus pulsatility index for veins (DV-PIV), uterine artery pulsatility index (UT-PI) and maternal serum free ß-human chorionic gonadotrophin ((ß-hCG) and pregnancy associated plasma protein-A (PAPP-A). The significant contributors were used to derive a model for first-trimester prediction of stillbirth.
Results: Significant contribution to prediction of stillbirth was provided by maternal factors, PAPP-A, UT-PI and DV-PIV. A model combining these variables predicted 40% of all stillbirths and 55% of those due to impaired placentation, at false positive rate of 10%; within the impaired placentation group the detection rate of stillbirth at 37 weeks (64% vs 42%).
Conclusions: A model based on maternal factors and first-trimester biomarkers can potentially predict more than half of subsequent stillbirths due to impaired placentation. The extent to which such stillbirths could be prevented remains to be determined
Midtrimester transvaginal ultrasound cervical length screening for spontaneous preterm birth in diamniotic twin pregnancies according to chorionicity
OBJECTIVE:
To compare the mean transvaginal ultrasound (TVU) cervical length (CL) at midtrimester screening for spontaneous preterm birth in asymptomatic monochorionic diamniotic versus dichorionic diamniotic twin pregnancies STUDY DESIGN: This was a multicenter retrospective cohort study. Study subjects were identified at the time of a routine second trimester fetal ultrasound exam at 18 0/7-23 6/7 weeks gestation. We excluded women that received progesterone, pessary, or cerclage. Distribution of CL was determined and normality was examined. Mean of TVU CL were compared between monochorionic diamniotic and dichorionic diamniotic pregnancies. The relationship of TVU CL with gestational age (GA) at delivery and incidence of spontaneous preterm birth (SPTB) at different TVU CL cut offs were assessed. Incidence of short TVU CL, defined as TVU CL ≤30 mm, was also calculated in the two groups.
RESULTS:
580 women with diamniotic twin pregnancies underwent TVU CL screening between 18 0/6 and 23 6/7 weeks. 175 (30.2%) were monochorionic diamniotic pregnancies, and 405 (69.8%) were dichorionic pregnancies. The demographic characteristics were similar on both groups. The mean GA at TVU CL was about 20 week in both groups. The mean TVU CL was significantly lower in the monochorionic diamniotic (32.8 ± 10.1) compared to the dichorionic (34.9 ± 8.6) group (MD -2.10 mm, 95% CI -3.91 to -0.29). TVU CL ≤30 mm was 16.6% (29/175) in the monochorionic group, and 11.9% (48/405) in the dichorionic group (aOR 1.48, 95% CI 1.03-2.43). Twins with a monochorionic diamniotic pregnancy had a significantly higher incidence of SPTB (53.1% vs 44.9%; aOR 1.22, 95% CI 1.22-1.79). For any given CL measured between 18 0-7 and 23 6/7 weeks, gestational age at delivery for monochorionic diamniotic pregnancies was about 2 weeks earlier compared to dichorionic pregnancies (MD -2.1 weeks; ANCOVA P < 0.001).
CONCLUSION:
Monochorionic diamniotic twin pregnancies had a higher rate of spontaneous preterm birth than dichorionic diamniotic pregnancies. The higher rate of spontaneous preterm delivery in monochorionic pregnancies is associated with lower midtrimester TVU CL when compared to dichorionic pregnancies
First-trimester or second-trimester screening, or both, for Down's syndrome
BACKGROUND: It is uncertain how best to screen pregnant women for the presence of fetal Down's syndrome: to perform first-trimester screening, to perform second-trimester screening, or to use strategies incorporating measurements in both trimesters.METHODS: Women with singleton pregnancies underwent first-trimester combined screening (measurement of nuchal translucency, pregnancy-associated plasma protein A [PAPP-A], and the free beta subunit of human chorionic gonadotropin at 10 weeks 3 days through 13 weeks 6 days of gestation) and second-trimester quadruple screening (measurement of alpha-fetoprotein, total human chorionic gonadotropin, unconjugated estriol, and inhibin A at 15 through 18 weeks of gestation). We compared the results of stepwise sequential screening (risk results provided after each test), fully integrated screening (single risk result provided), and serum integrated screening (identical to fully integrated screening, but without nuchal translucency).RESULTS: First-trimester screening was performed in 38,167 patients; 117 had a fetus with Down's syndrome. At a 5 percent false positive rate, the rates of detection of Down's syndrome were as follows: with first-trimester combined screening, 87 percent, 85 percent, and 82 percent for measurements performed at 11, 12, and 13 weeks, respectively; with second-trimester quadruple screening, 81 percent; with stepwise sequential screening, 95 percent; with serum integrated screening, 88 percent; and with fully integrated screening with first-trimester measurements performed at 11 weeks, 96 percent. Paired comparisons found significant differences between the tests, except for the comparison between serum integrated screening and combined screening.CONCLUSIONS: First-trimester combined screening at 11 weeks of gestation is better than second-trimester quadruple screening but at 13 weeks has results similar to second-trimester quadruple screening. Both stepwise sequential screening and fully integrated screening have high rates of detection of Down's syndrome, with low false positive rates
Identifying Patterns of Multimorbidity in Older Americans: Application of Latent Class Analysis
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134156/1/jgs14201_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134156/2/jgs14201.pd
Road Friction Virtual Sensing:A Review of Estimation Techniques with Emphasis on Low Excitation Approaches
In this paper, a review on road friction virtual sensing approaches is provided. In particular, this work attempts to address whether the road grip potential can be estimated accurately under regular driving conditions in which the vehicle responses remain within low longitudinal and lateral excitation levels. This review covers in detail the most relevant effect-based estimation methods; these are methods in which the road friction characteristics are inferred from the tyre responses: tyre slip, tyre vibration, and tyre noise. Slip-based approaches (longitudinal dynamics, lateral dynamics, and tyre self-alignment moment) are covered in the first part of the review, while low frequency and high frequency vibration-based works are presented in the following sections. Finally, a brief summary containing the main advantages and drawbacks derived from each estimation method and the future envisaged research lines are presented in the last sections of the paper
The companion dog as a model for human aging and mortality
Around the world, human populations have experienced large increases in average lifespan over the last 150 years, and while individuals are living longer, they are spending more years of life with multiple chronic morbidities. Researchers have used numerous laboratory animal models to understand the biological and environmental factors that influence aging, morbidity, and longevity. However, the most commonly studied animal species, laboratory mice and rats, do not experience environmental conditions similar to those to which humans are exposed, nor do we often diagnose them with many of the naturally occurring pathologies seen in humans. Recently, the companion dog has been proposed as a powerful model to better understand the genetic and environmental determinants of morbidity and mortality in humans. However, it is not known to what extent the age-related dynamics of morbidity, comorbidity, and mortality are shared between humans and dogs. Here, we present the first large-scale comparison of human and canine patterns of age-specific morbidity and mortality. We find that many chronic conditions that commonly occur in human populations (obesity, arthritis, hypothyroidism, and diabetes), and which are associated with comorbidities, are also associated with similarly high levels of comorbidity in companion dogs. We also find significant similarities in the effect of age on disease risk in humans and dogs, with neoplastic, congenital, and metabolic causes of death showing similar age trajectories between the two species. Overall, our study suggests that the companion dog may be an ideal translational model to study the many complex facets of human morbidity and mortality
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