The strain field of a crack in polygranular isotropic nuclear graphite, a quasi-brittle material, has been studied during stable fracture propagation. Synchrotron X-ray computed tomography and strain ...mapping by diffraction were combined with digital volume correlation and phase congruency image analysis to extract the full field displacements and elastic crystal strains. The measured displacement fields have been analysed using a Finite Element method to extract the elastic strain energy release rate as a J-integral. Non-linear properties described the effect of microcracking on the elastic modulus in the fracture process zone. The analysis was verified by the good agreement of the predicted and measured elastic strain fields when using the non-linear model. The intrinsic critical elastic strain energy release rate for mode I crack propagation is approximately 200 J m−2.
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Acetyl-CoA synthetase (ACS) and acetate ligase (ACD) are widespread among microorganisms, including archaea, and play an important role in their carbon metabolism, although only a few of these ...enzymes have been characterized. Anaerobic methanotrophs (ANMEs) have been reported to convert methane anaerobically into CO
, polyhydroxyalkanoate, and acetate. Furthermore, it has been suggested that they might be able to use acetate for anabolism or aceticlastic methanogenesis. To better understand the potential acetate metabolism of ANMEs, we characterized an ACS from ANME-2a as well as an ACS and an ACD from ANME-2d. The conversion of acetate into acetyl-CoA (
of 8.4 μmol mg
min
and
of 0.7 mM acetate) by the monomeric 73.8-kDa ACS enzyme from ANME-2a was more favorable than the formation of acetate from acetyl-CoA (
of 0.4 μmol mg
min
and
of 0.2 mM acetyl-CoA). The monomeric 73.4-kDa ACS enzyme from ANME-2d had similar
values for both directions (
of 0.9 μmol mg
min
versus
of 0.3 μmol mg
min
). The heterotetrameric ACD enzyme from ANME-2d was active solely in the acetate-producing direction. Batch incubations of an enrichment culture dominated by ANME-2d fed with
C
-labeled acetate produced 3 μmol of
Cmethane in 7 days, suggesting that this anaerobic methanotroph might have the potential to reverse its metabolism and perform aceticlastic methanogenesis using ACS to activate acetate albeit at low rates (2 nmol g dry weight
min
). Together, these results show that ANMEs may have the potential to use acetate for assimilation as well as to use part of the surplus acetate for methane production.
Acetyl-CoA plays a key role in carbon metabolism and is found at the junction of many anabolic and catabolic reactions. This work describes the biochemical properties of ACS and ACD enzymes from ANME-2 archaea. This adds to our knowledge of archaeal ACS and ACD enzymes, only a few of which have been characterized to date. Furthermore, we validated the
activity of ACS in ANME-2d, showing the conversion of acetate into methane by an enrichment culture dominated by ANME-2d.
Abstract Background Antithrombotic therapy for acute myocardial infarction (MI) with atrial fibrillation (AF) among higher risk older patients treated with percutaneous coronary intervention (PCI) ...remains unclear. Objectives This study sought to determine appropriate antithrombotic therapy for acute MI patients with AF treated with PCI. Methods We examined 4,959 patients ≥65 years of age with acute MI and AF who underwent coronary stenting (Acute Coronary Treatment and Intervention Outcomes Network Registry–Get With the Guidelines). The primary effectiveness outcome was 2-year major adverse cardiac events (MACE) comprising death, readmission for MI, or stroke; the primary safety outcome was bleeding readmission. Outcomes with dual antiplatelet therapy (DAPT) or triple therapy (DAPT plus warfarin) were compared using Cox proportional hazard modeling with inverse probability-weighted propensity adjustment. Results Among 4,959 patients, 27.6% (n = 1,370) were discharged on triple therapy. Relative to DAPT, patients on triple therapy had a similar risk of MACE (adjusted hazard ratio HR: 0.99 95% confidence interval (CI): 0.86 to 1.16) but significantly greater risk of bleeding requiring hospitalization (adjusted HR: 1.61 95% CI: 1.31 to 1.97) and greater risk of intracranial hemorrhage (adjusted HR: 2.04 95% CI: 1.25 to 3.34). Of 1,591 Medicare Part D patients, 90-day post-discharge warfarin persistence among patients discharged on warfarin was 93.2% (n = 412). Results of 90-day landmark analyses comparing triple therapy versus DAPT in patients persistently on warfarin versus those not discharged on warfarin who had not filled a warfarin prescription were similar to our primary findings. Conclusions Approximately 1 in 4 older AF patients undergoing PCI for MI were discharged on triple therapy. Those receiving triple therapy versus DAPT had higher rates of major bleeding without a measurable difference in composite MI, death, or stroke.
Abstract Readmission has been cited as an important quality measure in the Patient Protection and Affordable Care Act. We queried an electronic database for all patients who underwent Total Hip ...Arthroplasty or Total Knee Arthroplasty at our institution from 2006 to 2010 and identified those readmitted within 90 days of surgery, reviewed their demographic and clinical data, and performed a multivariable logistic regression analysis to determine significant risk factors. The overall 90-day readmission rate was 7.8%. The most common readmission diagnoses were related to infection and procedure-related complications. An increased likelihood of readmission was found with coronary artery disease, diabetes, increased LOS, underweight status, obese status, age (over 80 or under 50), and Medicare. Procedure-related complications and wound complications accounted for more readmissions than any single medical complication.
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an autosomal dominant small-vessel disease caused by mutations of the NOTCH3 gene. It typically ...presents with migraine, recurrent brain ischaemia, and cognitive disorders. Seizures rarely present as the initial manifestation, with non-convulsive status epilepticus being even less frequent. We present a series of 3 related patients with this arteriopathy, 2 of whom presented status epilepticus as a manifestation of the disease.
Objectives This study sought to evaluate the characteristics, therapies, and outcomes of patients with chronic kidney disease (CKD) presenting with non–ST-segment elevation myocardial infarction ...(NSTEMI) and managed with percutaneous coronary intervention (PCI). This specific population has not been evaluated previously. Background Among patients with acute coronary syndrome, the presence of renal dysfunction is associated with an increased risk of death and major bleeding. Methods We examined data on 40,074 NSTEMI patients managed with PCI who were captured by the ACTION (Acute Coronary Treatment and Intervention Outcomes Network) registry. Patients were divided according to baseline renal function in 4 groups: no CKD and CKD stages 3, 4, and 5. Results Overall, 31.1% (n = 12,045) of patients with NSTEMI undergoing PCI had CKD. Compared with patients with normal renal function, CKD patients managed with PCI had significantly more history of myocardial infarction, heart failure, and more 3-vessel coronary artery disease. They received fewer antithrombotic therapies but were treated more frequently with bivalirudin. In addition, they had significantly higher rates of in-hospital mortality and major bleeding. CKD stage 4 was associated with the highest risk of adverse events relative to no CKD. The multivariable adjusted odds ratios of in-hospital mortality for CKD stages 3, 4, and 5 relative to no CKD were 2.0, 2.8, and 2.6, respectively (global p value <0.0001), and the analogous adjusted odds ratios of major bleeding were 1.5, 2.8, and 1.8, respectively (global p value <0.0001). Conclusions CKD patients presenting with NSTEMI and managed with PCI have more comorbidities and receive guideline-recommended therapies less frequently than do patients without CKD. CKD is strongly associated with in-hospital mortality and bleeding in NSTEMI patients undergoing PCI.
Chitosan is very efficient at removing cadmium through chelation mechanisms involving amine groups of chitosan. The optimum pH is 7, and in acidic solutions, the protonation of the biopolymer reduces ...the binding of cadmium on amine groups due to electrostatic repulsion. The influence of particle size, temperature and agitation speed on metal sorption is investigated using chitosan flakes and chitosan gel beads. Temperature and agitation speed hardly influence equilibria and kinetics in the selected experimental conditions corresponding to a large sorbent dosage. The major effect on sorption performance is due to sorbent particle size, especially for chitosan flakes. Though intraparticle diffusion represents an important step in the kinetic control, the contribution of external diffusion may not be neglected.
Neutron diffraction and synchrotron X-ray diffraction and imaging have been applied to study, in situ, the mechanical response to tensile and bending loading of polygranular Gilsocarbon nuclear grade ...near-isotropic graphite (grade IM1-24). Digital image correlation of X-ray radiographs and digital volume correlation of tomographs allow measurement of bulk elastic moduli and examination of the heterogeneity of deformation in the microstructure. Both the neutron and X-ray studies show the application of tensile strain reduces the bulk elastic modulus. A permanent set is observed to develop with applied tensile strain. The elastic strains within the graphite crystals were measured by diffraction; a cross-correlation analysis method has been applied for greater speed, robustness and improved precision in the measurement of the change in basal plane separation distance. In compression, a linear relation is observed between the elastic strains in the graphite crystals and the applied strain. In tension, this relationship is non-linear. The results are discussed with respect to the distribution of elastic and inelastic strain within the graphite microstructure. It is deduced that the significant residual elastic strains in the as-manufactured graphite are relaxed by microcracking as tensile strain is applied.
Abstract Readmission rates have been cited as an important quality measure in the Affordable Care Act. Accordingly, understanding and accurately tracking the causes for readmission will be ...increasingly important. We queried an electronic database for all patients who underwent primary THA or TKA at our institution from 2006 through 2010. We identified those readmitted within 90 days of surgery and analyzed 87 random de-identified medical records. We then assigned a clinical diagnosis for each readmission, which was then compared with the coder-derived diagnosis by ICD-9 code. The overall 90-day readmission rate was 7.9%. We identified 22 of 87 patients for whom there was disagreement (25.3%, 95% CI = 16.6–35.8%). The most common were procedure-related complications. Coded diagnoses frequently did not correlate with the physician-derived diagnoses. The unverified use of coded readmission diagnoses in calculating quality measures may not be clinically relevant.
Hemophilia is an X-linked recessive deficiency of clotting factor VIII (hemophilia A) or IX (hemophilia B) that can result in hemarthrosis of various joints, including the elbow. Left unchecked, this ...can lead to progressive joint destruction and significant morbidity. Appropriate management of the elbow joint through prophylactic measures, accurate imaging, and timely intervention is essential. Replacing or supplementing deficient factor with a plasma-derived or recombinant factor concentrate can minimize bleeding episodes. Joints should be routinely monitored for damage. Plain films offer an inexpensive window into bone disease and joint space changes but lack soft tissue detail and may not detect early changes. Magnetic resonance imaging provides a high level of detail but may be limited by its cost and need for sedation in younger patients. Ultrasound may not achieve the same level of resolution as magnetic resonance imaging, but it is increasingly used as a convenient, effective, and relatively inexpensive alternative. Patients who experience hemarthrosis of the elbow with joint damage often require more invasive treatment. Radiosynovectomy and arthroscopic synovectomy are effective at minimizing pain and preventing future bleeding episodes, whereas extensive joint damage may necessitate total elbow replacement.
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