Reach- and catchment-scale determinants of the distribution of freshwater mussels (Bivalvia: Unionidae) in south-eastern Michigan, U.S.A.

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73643/1/j.1365-2426.2003.01165.x.pd

External stress-corrosion cracking of a 1.22-m-diameter type 316 stainless steel air valve

An investigation was conducted to determine the cause of the failure of a massive AISI Type 316 stainless steel valve which controlled combustion air to a jet engine test facility. Several through-the-wall cracks were present near welded joints in the valve skirt. The valve had been in outdoor service for 18 years. Samples were taken in the cracked regions for metallographic and chemical analyses. Insulating material and sources of water mist in the vicinity of the failed valve were analyzed for chlorides. A scanning electron microscope was used to determine whether foreign elements were present in a crack. On the basis of the information generated, the failure was characterized as external stress-corrosion cracking. The cracking resulted from a combination of residual tensile stress from welding and the presence of aqueous chlorides. Recommended countermeasures are included

miRNA-140-5p: new avenue for pulmonary arterial hypertension drug development?

Pulmonary arterial hypertension (PAH) is a rare but fatal disease. Pathologically, PAH is characterised by sustained vasoconstriction and progressive obliteration of small pulmonary arteries through a process of medial thickening, intimal fibrosis and the formation of angioproliferative lesions. Current treatments target the sustained vasoconstriction via either the prostacyclin, endothelin or nitric oxide pathway but do little to address the underlying progressive proliferative vascular disease. Dysregulated expression of microRNA (miR) has been identified in PAH and we have recently highlighted reduced miR-140-5p in patients with PAH. Replacement of miR-140-5p attenuated disease in animal models with the regulation of Smurf1, a E3 ubiquitin ligase targeting BMPR2 as one identified mechanism. These data highlight Smurf1 inhibition as a treatment for PAH

Lysozyme encapsulated gold nanoclusters for probing the early stage of lysozyme aggregation under acidic conditions

Protein aggregation can lead to several incurable amyloidosis diseases. The full aggregation pathway is not fully understood, creating the need for new methods of studying this important biological phenomenon. Lysozyme is an amyloidogenic protein which is often used as a model protein for studying amyloidosis. This work explores the potential of employing Lysozyme encapsulated gold nanoclusters (Ly-AuNCs) to study the protein’s aggregation. The fluorescence emission properties of Ly-AuNCs were studied in the presence of increasing concentrations of native lysozyme and as a function of pH, of relevance in macromolecular crowding and inflammation-triggered aggregation. AuNC fluorescence was observed to both redshift and increase in intensity as pH is increased or when native lysozyme is added to a solution of Ly-AuNCs at pH 3. The long (μs) fluorescence lifetime component of AuNC emission was observed to decrease under both conditions. Interestingly it was found via Time Resolved Emission Spectra (TRES) that both AuNC fluorescence components increase in intensity and redshift with increasing pH while only the long lifetime component of AuNC was observed to change when adding native lysozyme to solution; indicating that the underlying mechanisms for the changes observed are fundamentally different for each case. It is possible that the sensitivity of Ly-AuNCs to native lysozyme concentration could be utilized to study early stage aggregation

Isometric hip and knee torque measurements as an outcome measure in robot assisted gait training

Strength changes in lower limb muscles following robot assisted gait training (RAGT) in subjects with incomplete spinal cord injury (ISCI) has not been quantified using objective outcome measures. To record changes in the force generating capacity of lower limb muscles (recorded as peak voluntary isometric torque at the knee and hip), before, during and after RAGT in both acute and subacute/chronic ISCI subjects using a repeated measures study design. Eighteen subjects with ISCI participated in this study (Age range: 26–63 years mean age = 49.3 ± 11 years). Each subject participated in the study for a total period of eight weeks, including 6 weeks of RAGT using the Lokomat system (Hocoma AG, Switzerland). Peak torques were recorded in hip flexors, extensors, knee flexors and extensors using torque sensors that are incorporated within the Lokomat. All the tested lower limb muscle groups showed statistically significant (p < 0.001) increases in peak torques in the acute subjects. Comparison between the change in peak torque generated by a muscle and its motor score over time showed a non-linear relationship. The peak torque recorded during isometric contractions provided an objective outcome measure to record changes in muscle strength following RAGT

Influence of the X-chromosome on neuroanatomy: evidence from Turner and Klinefelter syndromes.

Studies of sex effects on neurodevelopment have traditionally focused on animal models investigating hormonal influences on brain anatomy. However, more recent evidence suggests that sex chromosomes may also have direct upstream effects that act independently of hormones. Sex chromosome aneuploidies provide ideal models to examine this framework in humans, including Turner syndrome (TS), where females are missing one X-chromosome (45X), and Klinefelter syndrome (KS), where males have an additional X-chromosome (47XXY). As these disorders essentially represent copy number variants of the sex chromosomes, investigation of brain structure across these disorders allows us to determine whether sex chromosome gene dosage effects exist. We used voxel-based morphometry to investigate this hypothesis in a large sample of children in early puberty, to compare regional gray matter volumes among individuals with one (45X), two (typically developing 46XX females and 46XY males), and three (47XXY) sex chromosomes. Between-group contrasts of TS and KS groups relative to respective sex-matched controls demonstrated highly convergent patterns of volumetric differences with the presence of an additional sex chromosome being associated with relatively decreased parieto-occipital gray matter volume and relatively increased temporo-insular gray matter volumes. Furthermore, z-score map comparisons between TS and KS cohorts also suggested that this effect occurs in a linear dose-dependent fashion. We infer that sex chromosome gene expression directly influences brain structure in children during early stages of puberty, extending our understanding of genotype-phenotype mechanisms underlying sex differences in the brain

Biochemical Validation of Patient-Reported Symptom Onset Time in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

AbstractObjectivesThis study evaluated a biochemical validation of patient-reported symptom onset time in patients with ST-segment elevation myocardial infarction (STEMI).BackgroundSymptom onset time is an important metric but has never been formally validated.MethodsThe Mayo Clinic Percutaneous Coronary Intervention (PCI) Registry was interrogated to obtain baseline, procedural, and outcome data on 607 STEMI patients undergoing primary PCI. Biochemical onset time was determined by backward extrapolation of serial increasing cardiac troponin T (cTnT) measurements.ResultsThe median patient-reported onset time was 12 min later than the calculated time of first cTnT increase and was therefore estimated to be 4.2 h later than the biochemical onset time (interquartile range: 1.9 to 11.1 h; p < 0.001), assuming a 4-h interval between coronary occlusion and first cTnT increase. Conventional ischemic time showed no association with infarct size (correlation with peak cTnT: r = 0.023; p = 0.61) or 1-year mortality (hazard ratio: 0.97 per doubling; 95% confidence interval: 0.68 to 1.40; p = 0.88). However, after recalculation of ischemic time with biochemical onset time, significant associations with infarct size (r = 0.14; p = 0.001) and 1-year mortality (hazard ratio: 1.70 per doubling; 95% confidence interval: 1.20 to 2.40; p = 0.003) were found. When underestimation of ischemic time by patient-reported onset time increased, so did the risk of mortality.ConclusionsAlthough our point estimate should be interpreted with caution, our study indicates that the actual onset of STEMI is likely to be earlier than the patient-reported onset time. Recalculation of ischemic time with biochemical onset time greatly enhanced its prognostic value. Underestimation of ischemic time by patient-reported onset time occurred more often in high-risk patients

Transesophageal Echocardiographically-Confirmed Pulmonary Vein Thrombosis in Association with Posterior Circulation Infarction

Pulmonary venous thromboembolism has only been identified as a cause of stroke with pulmonary arteriovenous malformations/fistulae, pulmonary neoplasia, transplantation or lobectomy, and following percutaneous radiofrequency ablation of pulmonary vein ostia in patients with atrial fibrillation. A 59-year-old man presented with a posterior circulation ischemic stroke. ‘Unheralded’ pulmonary vein thrombosis was identified on transesophageal echocardiography as the likely etiology. He had no further cerebrovascular events after intensifying antithrombotic therapy. Twenty-eight months after initial presentation, he was diagnosed with metastatic pancreatic adenocarcinoma and died 3 months later. This report illustrates the importance of doing transesophageal echocardiography in presumed ‘cardioembolic’ stroke, and that potential ‘pulmonary venous thromboembolic’ stroke may occur in patients without traditional risk factors for venous thromboembolism. Consideration should be given to screening such patients for occult malignancy

Petrographic characterization of lunar soils: Application of x ray digital-imaging to quantitative and automated analysis

The rocks and soils of the moon will be the raw materials for various engineering needs at a lunar base, such as sources of hydrogen, oxygen, metals, etc. The material of choice for most of the bulk needs is the regolith and its less than 1 cm fraction, the soil. For specific mineral resources it may be necessary to concentrate minerals from either rocks or soils. Therefore, quantitative characterizations of these rocks and soils are necessary in order to better define their mineral resource potential. However, using standard point-counting microscopic procedures, it is difficult to quantitatively determine mineral abundances and virtually impossible to obtain data on mineral distributions within grains. As a start to fulfilling these needs, Taylor et al. and Chambers et al. have developed a procedure for characterization of crushed lunar rocks using x ray digital imaging. The development of a similar digital imaging procedure for lunar soils as obtained from a spectrometer is described

Lunar mineral feedstocks from rocks and soils: X-ray digital imaging in resource evaluation

The rocks and soils of the Moon provide raw materials essential to the successful establishment of a lunar base. Efficient exploitation of these resources requires accurate characterization of mineral abundances, sizes/shapes, and association of 'ore' and 'gangue' phases, as well as the technology to generate high-yield/high-grade feedstocks. Only recently have x-ray mapping and digital imaging techniques been applied to lunar resource evaluation. The topics covered include inherent differences between lunar basalts and soils and quantitative comparison of rock-derived and soil-derived ilmenite concentrates. It is concluded that x-ray digital-imaging characterization of lunar raw materials provides a quantitative comparison that is unattainable by traditional petrographic techniques. These data are necessary for accurately determining mineral distributions of soil and crushed rock material. Application of these techniques will provide an important link to choosing the best raw material for mineral beneficiation