932 research outputs found
Using an unconventional climate record to link glacimarine sediments to turbidite frequencey in the
Master of ScienceGeologyUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/115441/1/39015074253363.pd
Mapping brain function during naturalistic viewing using high-density diffuse optical tomography
Recommended from our members
Diagnosis of Spinocerebellar Ataxia in the West Indies
Background: Access to medical care in many regions is limited by socioeconomic status, at both the individual and the community level. This report describes the diagnostic process of a family residing on an underserved Caribbean island where routine neurological care is typically addressed by general practitioners, and genetic diagnosis is not available through regular medical channels. The diagnosis and management of neurodegenerative disorders is especially challenging in this setting.
Case Report: We diagnosed a family with spinocerebellar ataxia type 3 (SCA3) in an underdeveloped nation with limited access to genetic medicine and no full-time neurologist.
Discussion: Molecular diagnosis of the SCAs can be challenging, even in developed countries. In the Caribbean, genetic testing is generally only available at a small number of academic centers. Diagnosis in this family was ultimately made by utilizing an international, pro bono, research-based collaborative process. Although access to appropriate resources, such as speech, physical, and occupational therapies, is limited on this island because of economic and geographical factors, the provision of a diagnosis appeared to be ultimately beneficial for this family. Identification of affected families highlights the need for access to genetic diagnosis in all communities, and can help direct resources where needed
Surface charge, fluidity, and calcium uptake by rat intestinal brush-border vesicles
AbstractBiological membrane outer surfaces are negatively charged and interact with positively charged calcium ion during calcium uptake. Positively charged polycations such as polyarginine bind to membranes with high affinity, displacing bound calcium from the membrane. We tested the effect of polyarginine on uptake of calcium by brush-border membrane vecicles and examined the responses in terms of membrane fluidity by electron paramagnetic resonance (EPR). Polyarginine inhibited the saturable component of calcium uptake by a mechanism combining inhibition characteristics of strontium (competitive) and magnesium (non-competitive). Unlike the inhibition of non-saturable calcium uptake by strontium and magnesium, polyarginine increased kD, the rate constant for non-saturable calcium uptake, by a concentration dependent mechanism. These effects of polyarginine on calcium uptake were associated with decreased membrane fluidity at the uptake temperature. These findings are consistent with a role for surface negative charge in determining both saturable and non-saturable calcium uptake. Increased membrane fluidity is associated with decreased saturable and increased non-saturable calcium uptake. Although increased fluidity might be involved in the increased kD for non-saturable uptake, the concentration-specific stimulating effect of polyarginine suggests a gating mechanism
Adenoviruses in Avian Hosts: Recent Discoveries Shed New Light on Adenovirus Diversity and Evolution
While adenoviruses cause infections in a wide range of vertebrates, members of the genus Atadenovirus, Siadenovirus, and Aviadenovirus predominantly infect avian hosts. Several recent studies on avian adenoviruses have encouraged us to re-visit previously proposed adenovirus evolutionary concepts. Complete genomes and partial DNA polymerase sequences of avian adenoviruses were extracted from NCBI and analysed using various software. Genomic analyses and constructed phylogenetic trees identified the atadenovirus origin from an Australian native passerine bird in contrast to the previously established reptilian origin. In addition, we demonstrated that the theories on higher AT content in atadenoviruses are no longer accurate and cannot be considered as a species demarcation criterion for the genus Atadenovirus. Phylogenetic reconstruction further emphasised the need to reconsider siadenovirus origin, and we recommend extended studies on avian adenoviruses in wild birds to provide finer evolutionary resolution
Three-dimensional numerical simulation of blood flow in mouse aortic arch around atherosclerotic plaques
Atherosclerosis is a progressive disease, involving the build-up of lipid streaks in artery walls, leading to plaques. Understanding the development of atherosclerosis and plaque vulnerability is critically important since plaque rupture can result in heart attack or stroke. Plaques can be divided into two distinct types: those likely to rupture (vulnerable) or less likely to rupture (stable). In the last decade, researchers have been interested in studying the influence of the mechanical effects (blood shear stress, pressure forces and structural stress) on the plaque formation, progression and rupture processes but no general agreement has been found. The purpose of the present work is to include more realistic conditions for the numerical calculations of the blood flow by implementing real geometries with plaques in the numerical model. Hemodynamical parameters are studied in both diseased and healthy configurations. The healthy configuration is obtained by removing numerically the plaques from three dimensional geometries obtained by micro-computed tomography. A new hemodynamical parameter is also introduced to relate the location of plaques to the characteristics of the flow in the healthy configuration
LIGO detector characterization in the second and third observing runs
The characterization of the Advanced LIGO detectors in the second and third observing runs has increased the sensitivity of the instruments, allowing for a higher number of detectable gravitational-wave signals, and provided confirmation of all observed gravitational-wave events. In this work, we present the methods used to characterize the LIGO detectors and curate the publicly available datasets, including the LIGO strain data and data quality products. We describe the essential role of these datasets in LIGO–Virgo Collaboration analyses of gravitational-waves from both transient and persistent sources and include details on the provenance of these datasets in order to support analyses of LIGO data by the broader community. Finally, we explain anticipated changes in the role of detector characterization and current efforts to prepare for the high rate of gravitational-wave alerts and events in future observing runs
Vascular Health in American Football Players: Cardiovascular Risk Increased in Division III Players
Studies report that football players have high blood pressure (BP) and increased cardiovascular risk. There are over 70,000 NCAA football players and 450 Division III schools sponsor football programs, yet limited research exists on vascular health of athletes. This study aimed to compare vascular and cardiovascular health measures between football players and nonathlete controls. Twenty-three athletes and 19 nonathletes participated. Vascular health measures included flow-mediated dilation (FMD) and carotid artery intima-media thickness (IMT). Cardiovascular measures included clinic and 24 hr BP levels, body composition, VO2 max, and fasting glucose/cholesterol levels. Compared to controls, football players had a worse vascular and cardiovascular profile. Football players had thicker carotid artery IMT (0.49 ± 0.06 mm versus 0.46 ± 0.07 mm) and larger brachial artery diameter during FMD (4.3 ± 0.5 mm versus 3.7 ± 0.6 mm), but no difference in percent FMD. Systolic BP was significantly higher in football players at all measurements: resting (128.2 ± 6.4 mmHg versus 122.4 ± 6.8 mmHg), submaximal exercise (150.4 ± 18.8 mmHg versus 137.3 ± 9.5 mmHg), maximal exercise (211.3 ± 25.9 mmHg versus 191.4 ± 19.2 mmHg), and 24-hour BP (124.9 ± 6.3 mmHg versus 109.8 ± 3.7 mmHg). Football players also had higher fasting glucose (91.6 ± 6.5 mg/dL versus 86.6 ± 5.8 mg/dL), lower HDL (36.5±11.2 mg/dL versus 47.1±14.8 mg/dL), and higher body fat percentage (29.2±7.9% versus 23.2±7.0%). Division III collegiate football players remain an understudied population and may be at increased cardiovascular risk
Fibrose cística e a triagem neonatal
The clinical and diagnostic aspects of cystic fibrosis have been extensively reviewed, with an emphasis on neonatal screening. This systematic literature review involved a search for relevant contributions in the PubMed and SciELO databases. The first references to cystic fibrosis date to the Middle Ages. Cystic fibrosis is the most frequent autosomal recessive hereditary disease among Caucasians (1:2,000 to 3,500). More than 1,000 mutations lead to the disease, the most common being "F508, with 70% prevalence among Canadian, Northern European, and American Caucasians and 23 to 55% prevalence among Brazilians. The basic defect is in chloride ion secretion. Cystic fibrosis screening has long been controversial, and after almost three decades, there are few nationwide programs (most are regional or local). However, the U.S. Centers for Disease Control and Prevention (CDC) has concluded that screening for cystic fibrosis is justified. The lack of a specific screening test and the ethnic heterogeneity of the Brazilian population pose challenges for neonatal screening.Aspectos clínicos e diagnósticos da fibrose cística são revistos de modo abrangente, com ênfase na triagem neonatal. Esta revisão sistematizada da literatura envolveu busca de contribuições relevantes nos bancos de dados PubMed e SciELO. Referências sobre fibrose cística existem desde a Idade Média. É a doença hereditária autossômica recessiva mais freqüente em caucasianos (1:2.000 a 3.500). Mais de mil mutações levam à doença, a mais comum: "F508 (prevalência: 70% em caucasianos canadenses, americanos e norte-europeus; de 23 a 55% em brasileiros). O defeito básico ocorre na secreção do íon cloro. Sua triagem é assunto polêmico e apesar de estar disponível há quase três décadas, por meio de diferentes protocolos, poucos programas de abrangência nacional existem. Entretanto, o Centers for Disease Control and Prevention, dos Estados Unidos, afirma que o rastreamento neonatal para fibrose cística é justificado. A falta de um teste específico e a heterogeneidade étnica da população brasileira dificultam sua triagem neonatal
Environmental Noise in Advanced LIGO Detectors
The sensitivity of the advanced LIGO detectors to gravitational waves can be affected by environmental disturbances external to the detectors themselves. Since the transition from the former initial LIGO phase, many improvements have been made to the equipment and techniques used to investigate these environmental effects. These methods have aided in tracking down and mitigating noise sources throughout the first three observing runs of the advanced detector era, keeping the ambient contribution of environmental noise below the background noise levels of the detectors. In this paper we describe the methods used and how they have led to the mitigation of noise sources, the role that environmental monitoring has played in the validation of gravitational wave events, and plans for future observing runs
- …