Vanadium oxide grafted on mesoporous silica SBA-15 has been synthesized using a controlled grafting process. Its structure has been thoroughly investigated using different characterization ...techniques, including N
2-physisorption, X-ray diffraction, transmission electron microscopy (TEM), Raman spectroscopy, H
2 temperature-programmed reduction, X-ray absorption near-edge structure (XANES), and extended X-ray absorption fine structure (EXAFS). The spectroscopic results revealed that under dehydrated conditions, the grafted vanadium domains are highly dispersed on the SBA-15 surface, composed predominately of isolated VO
4 units with distorted tetrahedral coordination. The suggested (
SiO)
3V
O sites on the silica surface include one short bond (∼1.54 Å) and three long bonds (1.74 Å). Methanol oxidation was used as a chemical probe reaction to examine the catalytic properties of these catalysts. At low vanadium loading, the vanadium species grafted on the surface show structural properties similar to those of vanadium-incorporated MCM-41 catalyst. However, the present mesoporous V-SBA-15 catalysts in the oxidation of methanol to formaldehyde show remarkable catalytic performance compared with that of VO
x
/SBA-15 catalysts synthesized through a conventional wet impregnation method, which has been attributed to the homogeneous dispersion and uniformity of the catalytic vanadium species achieved on the SBA-15 support with large pore diameter and surface area. The acidic properties of V-SBA-15 was investigated by pyridine temperature-programmed desorption, which indicated the existence of both Lewis and Brönsted acid sites of the surface.
Gemcitabine is generally considered to constitute first-line therapy for pancreatic cancer. To determine whether the addition of fluorouracil (5-FU) improves on the results from single-agent ...gemcitabine, the Eastern Cooperative Oncology Group (ECOG) compared gemcitabine plus bolus 5-FU with gemcitabine alone for patients with advanced pancreatic carcinoma.
This trial involved patients with biopsy-proven, advanced carcinoma of the pancreas not amenable to surgical resection. Patients were randomized to receive either gemcitabine alone (1,000 mg/m(2)/wk) weekly for 3 weeks of every 4 or to receive gemcitabine (1,000 mg/m(2)/wk) followed by 5-FU (600 mg/m(2)/wk) weekly on the same schedule. The primary end point of the trial was survival, with secondary end points of time to progression and response rate.
Of 327 patients enrolled over 18 months, 322 were eligible. Overall, the median survival was 5.4 months for gemcitabine alone and 6.7 months for gemcitabine plus 5-FU (P =.09). Progression-free survival for gemcitabine alone was 2.2 months, compared with 3.4 months for gemcitabine plus 5-FU (P =.022). Objective responses were uncommon and were observed in only 5.6% of patients treated with gemcitabine and 6.9% of patients treated with gemcitabine plus 5-FU. Most toxicities were hematologic or gastrointestinal; no significant differences were noted between the two treatment arms.
5-FU, administered in conjunction with gemcitabine, did not improve the median survival of patients with advanced pancreatic carcinoma compared with single-agent gemcitabine. Further studies with other combinations of gemcitabine and 5-FU are not compelling, and clinical trial resources should address other combinations and novel agents.
Objective vortex detection in an astrophysical dynamo Rempel, E. L; Chian, A. C.-L; Beron-Vera, F. J ...
Monthly notices of the Royal Astronomical Society. Letters,
03/2017, Letnik:
466, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
A novel technique for detecting Lagrangian vortices is applied to a helical magnetohydrodynamic dynamo simulation. The vortices are given by tubular level surfaces of the Lagrangian averaged ...vorticity deviation, the trajectory integral of the normed difference of the vorticity from its spatial mean. This simple method is objective, i.e. invariant under time-dependent rotations and translations of the coordinate frame. We also adapt the technique to use it on magnetic fields and propose the method of integrated averaged current deviation to determine precisely the boundary of magnetic vortices. The relevance of the results for the study of vortices in solar plasmas is discussed.
In North America, no effective therapy has been available for patients with progressive metastatic colorectal cancer after front-line treatment with irinotecan, bolus fluorouracil (FU), and ...leucovorin (IFL).
Patients with metastatic colorectal cancer who progressed after IFL therapy were randomly assigned to bolus and infusional FU and leucovorin (LV5FU2), single-agent oxaliplatin, or the combination (FOLFOX4). This planned interim analysis evaluated objective response rate (RR), time to tumor progression (TTP), and alleviation of tumor-related symptoms (TRS) in an initial cohort of patients.
Between November 2000 and September 2001, 463 patients from 120 sites in North America were randomly assigned to treatment. FOLFOX4 proved superior to LV5FU2 in all measures of clinical efficacy. Objective RRs determined by an independent radiology panel were 9.9% for FOLFOX4 versus 0% for LV5FU2 (Fisher's exact test, P <.0001). Median TTP was 4.6 months for FOLFOX4 versus 2.7 months for LV5FU2 (two-sided, stratified log-rank test, P <.0001). Relief of TRS occurred in 33% of patients treated with FOLFOX4 versus 12% of patients treated with LVFU2 (chi2 test, P <.001). Single-agent oxaliplatin was not superior to LV5FU2 in any measure of efficacy. Patients treated with FOLFOX4 experienced a higher incidence of clinically significant toxicities than patients treated with LV5FU2, but these toxicities were predictable and did not result in a higher rate of treatment discontinuation or 60-day mortality rate.
For patients with metastatic colorectal cancer, second-line treatment with FOLFOX4 is superior to treatment with LVFU2 in terms of RR, TTP, and relief of TRS.
To study the variable clinical picture and exercise tolerance of patients with phosphoglycerate kinase (PGK) 1 deficiency and how it relates to residual PGK enzyme activity.
In this case series ...study, we evaluated 7 boys and men from 5 families with PGK1 deficiency. Five had pure muscle symptoms, while 2 also had mild intellectual disability with or without anemia. Muscle glycolytic and oxidative capacities were evaluated by an ischemic forearm exercise test and by cycle ergometry.
Enzyme levels of PGK were 4% to 9% of normal in red cells and 5% to10% in muscle in pure myopathy patients and 2.6% in both muscle and red cells in the 2 patients with multisystem involvement. Patients with pure myopathy had greater increases in lactate with ischemic exercise (2-3 mmol/L) vs the 2 multisystem-affected patients (<1 mmol/L). Myopathy patients had higher oxidative capacity in cycle exercise vs multisystem affected patients (≈30 vs ≈15 mL/kg per minute). One multisystem-affected patient developed frank myoglobinuria after the short exercise test.
This case series study of PGK1 deficiency suggests that the level of impaired glycolysis in PGK deficiency is a major determinant of phenotype. Lower glycolytic capacity in PGK1 deficiency seems to result in multisystem involvement and increased susceptibility to exertional rhabdomyolysis.
Surgical resection of adenocarcinoma of the stomach is curative in less than 40 percent of cases. We investigated the effect of surgery plus postoperative (adjuvant) chemoradiotherapy on the survival ...of patients with resectable adenocarcinoma of the stomach or gastroesophageal junction.
A total of 556 patients with resected adenocarcinoma of the stomach or gastroesophageal junction were randomly assigned to surgery plus postoperative chemoradiotherapy or surgery alone. The adjuvant treatment consisted of 425 mg of fluorouracil per square meter of body-surface area per day, plus 20 mg of leucovorin per square meter per day, for five days, followed by 4500 cGy of radiation at 180 cGy per day, given five days per week for five weeks, with modified doses of fluorouracil and leucovorin on the first four and the last three days of radiotherapy. One month after the completion of radiotherapy, two five-day cycles of fluorouracil (425 mg per square meter per day) plus leucovorin (20 mg per square meter per day) were given one month apart.
The median overall survival in the surgery-only group was 27 months, as compared with 36 months in the chemoradiotherapy group; the hazard ratio for death was 1.35 (95 percent confidence interval, 1.09 to 1.66; P=0.005). The hazard ratio for relapse was 1.52 (95 percent confidence interval, 1.23 to 1.86; P<0.001). Three patients (1 percent) died from toxic effects of the chemoradiotherapy; grade 3 toxic effects occurred in 41 percent of the patients in the chemoradiotherapy group, and grade 4 toxic effects occurred in 32 percent.
Postoperative chemoradiotherapy should be considered for all patients at high risk for recurrence of adenocarcinoma of the stomach or gastroesophageal junction who have undergone curative resection.
Accurate and reliable quantification of the abundance of mitochondrial DNA (mtDNA) molecules, both wild-type and those harbouring pathogenic mutations, is important not only for understanding the ...progression of mtDNA disease but also for evaluating novel therapeutic approaches. A clear understanding of the sensitivity of mtDNA measurement assays under different experimental conditions is therefore critical, however it is routinely lacking for most published mtDNA quantification assays. Here, we comprehensively assess the variability of two quantitative Taqman real-time PCR assays, a widely-applied MT-ND1/MT-ND4 multiplex mtDNA deletion assay and a recently developed MT-ND1/B2M singleplex mtDNA copy number assay, across a range of DNA concentrations and mtDNA deletion/copy number levels. Uniquely, we provide a specific guide detailing necessary numbers of sample and real-time PCR plate replicates for accurately and consistently determining a given difference in mtDNA deletion levels and copy number in homogenate skeletal muscle DNA.
Deficiencies in respiratory-chain complexes lead to a variety of clinical phenotypes resulting from inadequate energy production by the mitochondrial oxidative phosphorylation system. Defective ...expression of mtDNA-encoded genes, caused by mutations in either the mitochondrial or nuclear genome, represents a rapidly growing group of human disorders. By whole-exome sequencing, we identified two unrelated individuals carrying compound heterozygous variants in TRMT5 (tRNA methyltransferase 5). TRMT5 encodes a mitochondrial protein with strong homology to members of the class I-like methyltransferase superfamily. Both affected individuals presented with lactic acidosis and evidence of multiple mitochondrial respiratory-chain-complex deficiencies in skeletal muscle, although the clinical presentation of the two affected subjects was remarkably different; one presented in childhood with failure to thrive and hypertrophic cardiomyopathy, and the other was an adult with a life-long history of exercise intolerance. Mutations in TRMT5 were associated with the hypomodification of a guanosine residue at position 37 (G37) of mitochondrial tRNA; this hypomodification was particularly prominent in skeletal muscle. Deficiency of the G37 modification was also detected in human cells subjected to TRMT5 RNAi. The pathogenicity of the detected variants was further confirmed in a heterologous yeast model and by the rescue of the molecular phenotype after re-expression of wild-type TRMT5 cDNA in cells derived from the affected individuals. Our study highlights the importance of post-transcriptional modification of mitochondrial tRNAs for faithful mitochondrial function.
Clinical indicators assess healthcare structures, processes, and outcomes. While used widely, the exact number and level of scientific evidence of these indicators remains unclear. The aim of this ...study was to evaluate the number, type, and evidence base of clinical process and structure indicators currently available for quality and safety measurement in perioperative care.
We performed a systematic review searching Medline, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane, Google Scholar, and System for Information in Grey Literature in Europe databases for English language human studies in adults (age >18) published in the past 10 years (January 2005–January 2016). We also included professional and governmental body publications and guidelines describing the development, validation, and use of structure and process indicators in perioperative care.
We identified 43 860 journal articles and 43 relevant indicator program publications. From these, we identified a total of 1282 clinical indicators, split into structure (36%, n=463) and process indicators (64%, n=819). The dimensions of quality most frequently addressed were effectiveness (38%, n=475) and patient safety (29%, n=363). The majority of indicators (53%, n=675) did not have a level of evidence ascribed in their literature. Patient-centred metrics accounted for the fewest published clinical indicators.
Despite widespread use, the majority of clinical indicators are not based on a strong level of scientific evidence. There may be scope in setting standards for the development and validation process of clinical indicators. Most indicators focus on the effectiveness, safety, and efficiency of care.
CRD4201501277.
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