Transuranic actinide reactions with simple gas-phase molecules.

The intent of this research is to conduct an experimental study of f-element chemistry fo r the purpose of identifying reaction trends and mechanisms of the early actinide metals with simple gas phase molecules . Previous research has elucidated some of the fundamenta l chemistry of the 4f elements,1-5 however, more complex chemistry is expected for the 5f serie s due to the inclusion of the 5f electrons in the valence shell . The matrix isolation approach, which is well-suited to the experimental study of transient species, will be used for sample collection, and IR/NIR/VIS spectroscopy will be employed to interrogate deposited matrices . The strength of this method lies in the use of isotopes of reactants, which permits the identification of guest molecules in a noble gas matrix by observation of vibrational frequenc y shifts and patterns upon isotopic substitution . Using this technique at the University of Virginia, the first noble gas-actinide bond has recently been identified, a weak U-Ar bond on the CUO molecule.6 Uranium has similarly been observed to bond to krypton and xenon, whereas thoriu m and the lanthanides have not exhibited this activity . It is expected that plutonium will be even more reactive in this respect . We will extend the body of actinide experimental evidence t o include the transuranic elements neptunium, plutonium, and americium reacted with isotopes o f oxygen, nitrogen, hydrogen, carbon monoxide, and carbon dioxide

Influence of halloysite nanotubes on physical and mechanical properties of cellulose fibres reinforced vinyl ester composites

Natural fibres are generally added to polymer matrix composites to produce materials with the desirable mechanical properties of higher specific strength and higher specific modulus while at the same time to maintain a low density and low cost. The physical and mechanical properties of polymer composites can be enhanced through the addition of nanofillers such as halloysite nanotubes. This article describes the fabrication of vinyl ester eco-composites and eco-nanocomposites and characterizes these samples in terms of water absorption, mechanical and thermal properties. Weight gain test and Fourier transform infrared analysis indicated that 5% halloysite nanotube addition gave favourable reduction in the water absorption and increased the fibre–matrix adhesion leading to improved strength properties in the eco-nanocomposites. However, halloysite nanotube addition resulted in reduced toughness but improved thermal stability

A KINETIC STUDY OF THE THERMAL DECOMPOSITION OF 2, 2, 4, 4-TETRAMETHYLCYCLOBUTANEDIONE USING TIME-RESOLVED FTIR

Author Institution: Department of chemistry, University of floridaSpectroscopic methods have been used for years to follow chemical process. We have used FTIR spectroscopy to follow the thermal decomposition of 2, 2, 4, 4-etramethycyelobutanedione (TMCBD) into one of its products, dimethylketene (DMK). This process is too fast to be followed accurately by standard IR spectroscopic methods. Using the time-resolved Fourier transform technique, many spectra can be collected in a very short period of time. This allows us to calculate the standard kinetics parameters by following the integrated peak areas of the TMCBD and DMK as a function of time

Interventions affecting mortality in critically ill and perioperative patients: A systematic review of contemporary trials

Purpose Confounders in randomized controlled trials (RCTs) reporting significant effects on mortality in critically ill patients using non-surgical techniques have not been systematically explored. We aimed to identify factors unrelated to the reported intervention that might have affected the findings and robustness of such trials. Methods We searched Pubmed/MEDLINE for all RCTs on any non-surgical interventions reporting an effect on unadjusted mortality in critically ill patients between 1/1/2000 and 1/12/2015. We assessed: the number needed to treat/harm (NNT or NNH), sample size, trial design (blinded/unblinded, single or multinational, single or multicenter (sRCT or mRCT)), intention to treat (ITT) analysis, and countries of origin. Results Almost half of RCTs were sRCTs. Median sample size was small, and 1/3 were not analyzed according to ITT principle. Lack of ITT analysis was associated with greater effect size (p = 0.0028). Harm was more likely in mRCTs (p = 0.002) and/or in blinded RCTs (p = 0.003). Blinded RCTs had double sample size (p = 0.007) and an increased NNT/NNH (p = 0.002). Finally, mRCTs had higher NNT (p = 0.005) and NNH (p = 0.02), and harm was only detected in studies from Western countries (p = 0.007). Conclusions These observations imply that major systematic biases exist and affect trial findings irrespective of the intervention being studied

Steroids and Survival in Critically Ill Adult Patients: A Meta-analysis of 135 Randomized Trials

Objective: Corticosteroids have important effects on intermediate outcomes in critically ill patients, but their effect on survival is unknown. The objective of this meta-analysis was to analyze the effect on mortality of corticosteroids in critical and perioperative settings. Design: A meta-analysis of randomized trials. Setting: PubMed, Embase, BioMed Central, Google Scholar, and the Cochrane Central Register of Controlled Trials were searched to February 1, 2018, for randomized trials comparing corticosteroids with placebo or standard care. Participants: Critically ill or surgical adult patients. Interventions: Corticosteroids compared with placebo or standard care. Measurements and Main Results: A total of 44,553 patients from 135 studies were included. Overall, mortality in the corticosteroid group and in the control group were similar (16% v 16%; p = 0.9). Subanalyses identified a beneficial effect of corticosteroids on survival in patients with respiratory system diseases (9% v 13%; p < 0.001) and bacterial meningitis (28% v 32%; p= 0.04), and a detrimental effect on survival in patients with traumatic brain injury (22% v 19%; p < 0.001). No differences in mortality were found in patients with cardiac diseases (7% v 6%; p = 0.7), in patients undergoing cardiac surgery (2.8% v 3.2% p = 0.14), and when treatment duration or patient age were considered. Conclusions: This meta-analysis documents the safety of corticosteroids in the overall critically ill population with the notable exception of brain injury patients, a setting where the authors confirmed their detrimental effect on survival. A possible beneficial effect of corticosteroids on survival was found among patients with respiratory diseases and in patients with bacterial meningitis

Gender-gap in randomized clinical trials reporting mortality in the perioperative setting and critical care: 20 years behind the scenes

Background: Women researchers might experience obstacles in academic environments and might be underrepresented in the authorship of articles published in peer-reviewed journals. Material and Methods: This is a cross-sectional analysis of female-led RCTs describing all interventions reducing mortality in critically ill and perioperative patients from 1981 to December 31, 2020. We searched PubMed/MEDLINE and EMBASE with the keywords RCTs and mortality. The gender of the first author was extracted and descriptive analysis was performed including the year of publication, impact factor, country of the first author, and methodological aspects. Results: We analyzed 340 RCTs, of which 42 (12%) were led by female researchers. The presence of women increased from 8% (14/172) until 2010 up to 17% (28/168) in 2010 and beyond. The United States, the United Kingdom, and Brazil were the main countries of origin of female researchers. Women authors conducted mainly single-center and single-nation studies as compared to male authors. The median impact factor of the target journal was 6 (3-27) in women vs. 7 (3-28) in men, with a p-value of 0.67; Critical Care Medicine, JAMA, and The New England Journal of Medicine were the most frequent target journals for both women and men. Conclusion: In the last 40 years, only one out of eight RCTs had a woman as the first author but the presence of women increased up to 17% by 2010 and beyond. The impact factor of publication target journals was high and not different between genders

Correction to: Tracheal intubation in critically ill patients: A comprehensive systematic review of randomized trials (Critical Care (2018) 22 (6) DOI: 10.1186/s13054-017-1927-3)

In the publication of this article [1], there was an error in a contributors Family Name. This has now been updated in the original article. \ua9 2019 The Author(s)