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The conversion of polyolefins to monomers would create a valuable carbon feedstock from the largest fraction of waste plastic. However, breakdown of the main chains in these polymers requires the cleavage of carbon–carbon bonds that tend to resist selective chemical transformations. Here, we report the production of propylene by partial dehydrogenation of polyethylene and tandem isomerizing ethenolysis of the desaturated chain. Dehydrogenation of high-density polyethylene with either an iridium-pincer complex or platinum/zinc supported on silica as catalysts yielded dehydrogenated material containing up to 3.2% internal olefins; the combination of a second-generation Hoveyda-Grubbs metathesis catalyst and [PdP( t Bu) 3 (μ-Br)] 2 as an isomerization catalyst selectively degraded this unsaturated polymer to propylene in yields exceeding 80%. These results show promise for the application of mild catalysis to deconstruct otherwise stable polyolefins.

We report a newly developed, palladium-catalyzed dehydrosilylation of terminal alkylsilanes that combines with chain-walking hydrosilylation to create a one-pot isomerization of internal olefins to...

We report a dehydroboration process that can be coupled with chain-walking hydroboration to create a one-pot, contra-thermodynamic, short- or long-range isomerization of internal olefins to terminal olefins. This dehydroboration occurs by a sequence comprising activation with a nucleophile, iodination, and base-promoted elimination. The isomerization proceeds at room temperature without the need for a fluoride base, and the substrate scope of this isomerization is expanded over those of previous isomerizations we have reported with silanes.

Many laboratory experiments and model development activities have been underway to better estimate the risk of a person indoors becoming infected with COVID-19. The current paper focusses on the near-field (distances about 5 m) transport and dispersion (TD) of the virons, treating them as inert tracers. The premise is that the TD process follows widely used basic analytical near-field formulations such as a slab model, a Gaussian plume model, or a diffusivity (K) model. A slab or Gaussian model is more appropriate for cloud sizes less than the distance scale of the turbulence, while a K model is more appropriate for cloud sizes larger than the distance scale. The proposed slab model is evaluated with observations from the TRANSCOM tracer experiment in Boeing 767 and 777 airplanes, which involved multiple release scenarios. Release rates of 1-μm plastic bead inert tracers were constant over 60 s from a mannequin's mouth and samplers were placed at about 40 nearby seat locations. A simple basic science near-field slab model is shown to agree with observations of maximum concentration and dose within a factor of two or three.

We report an approach to conducting the hydroaminomethylation of diverse α-olefins with a wide range of alkyl, aryl, and heteroarylamines at low temperatures (70–80 °C) and pressures (1.0–3.4 bar) of synthesis gas. This approach is based on simultaneously using two distinct catalysts that are mutually compatible. The hydroformylation step is catalyzed by a rhodium diphosphine complex, and the reductive amination step, which is conducted as a transfer hydrogenation with aqueous, buffered sodium formate as the reducing agent, is catalyzed by a cyclometallated iridium complex. By adjusting the ratio of CO to H(2), we conducted the reaction at one atmosphere of gas with little change in yield. A diverse array of olefins and amines, including hetreroarylamines that do not react under more conventional conditions with a single catalyst, underwent hydroaminomethylation with this new system, and the pharmaceutical ibutilide was prepared in higher yield and under milder conditions than those reported with a single catalyst.

Background: A new tool, the AGREE-REX, was recently developed to support the development, reporting, and assessment of clinical practice guidelines’ (CPGs) recommendations, and to complement the AGREE II tool. We assessed the credibility and implementability of 161 CPGs recommendations using the AGREE-REX draft tool. Methods: Cross sectional study. CPGs were assessed by two independent appraisers using the AGREE-REX draft tool. The CPGs were rated with the tool’s 7-point response scale for each item. Differences between CPGs according to country, year and type of organization (government-supported/professional society) were evaluated. One-way ANOVA tests were used to examine differences in the score. Results: Recommendations from 161 CPGs from 70 organizations were appraised by 322 participants from 51 countries, using the AGREE-REX draft tool. The total overall average score of the recommendations was 4.23 (standard deviation(SD)=1.14). AGREE-REX items that scored the highest were (mean; SD): Evidence (5.51; SD=1.14), Clinical relevance (5.95; SD=0.8), and Patients/population relevance (4.87; SD=1.33), while the lowest scores were observed for the Policy values (3.44; SD=1.53), Local applicability (3,56; SD=1.47) and Resources, tools and capacity (3.49; SD=1.44) items. CPGs developed by government-supported organizations and developed in the UK and Canada had significantly higher recommendation quality scores with the AGREE-REX tool (p=0.01) than their comparators.Conclusions: We found that there is significant room for improvement of some CPGs such as the considerations of patient/population values, policy values, local applicability and resources, tools and capacity. These findings may be considered a baseline upon which to measure future improvements in the quality of CPGs.Contribution to the literature· We applied the AGREE II and the recently developed tool (AGREE-REX draft version), to assess quality, credibility and implementability of 161 international clinical practice guidelines (CPGs). The AGREE REX draft tool was applied by 322 guidelines’ developers, users and researchers from 51 countries.· The scores of the AGREE REX draft tool items were higher in those items related to the quality of the evidence and the clinical relevance. The items related to patients and population relevance and implementation relevance scored in the mid-range, while the items related to patients/population or policy values, the alignment of values, the local applicability, and the resouces, tools and capacity items scored low.· CPGs produced by government-supported organizations scored higher on all the items of the AGREE-REX draft tool than those produced by professional societies or other types of groups, and CPGs produced in United Kingdom and Canada scored higher in selected items in comparison to United States and international CPGs· The correlations between the overall AGREE-REX draft tool and AGREE II domains were low, except for the Applicability domain where the correlation was modest.

We report a contra-thermodynamic isomerization of internal olefins to terminal olefins driven by redox reactions and formation of Si-F bonds. This process involves chain-walking hydrosilylation of internal olefins and subsequent formal retro-hydrosilylation. The process rests upon the high activities of platinum hydrosilylation catalysts for isomerization of metal alkyl intermediates and a new, metal-free process for the conversion of alkylsilanes to alkenes. By this approach, 1,2-disubstituted and trisubstituted olefins are converted to terminal olefins.

Abstract: We compared the same outcome data obtained from two different sources (self-report surveys and organizational documents) in order to examine their relative performance in evaluating the effect of knowledge translation strategies on evidence-informed decision-making. Our data came from a randomized controlled trial that evaluated the impact of knowledge translation strategies on promoting evidence-informed decision-making in public health units across Canada. We found that self-report surveys identified more outcome data than organizational documents; the types of documents that identified the most outcome data were evaluation plans, operational plans, work plans, and evaluation data; the types of documents that identified the least outcome data were meeting minutes, statistics/annual reports, and strategic plans; and evaluation plans, operational plans, and work plans together provide more outcome data than other combinations. Overall, our study suggests that evidence-informed decision-making may be appropriately measured by using multiple data sources in order to compare data across sources and to gain a more accurate representation of the results. Our findings also suggest that if organizational documents are used as a source of data in knowledge translation research, then specific types should be used in order to maximize the likelihood of identifying measures of effectiveness.

Cross-sectional studies have shown that children with developmental coordination disorder (DCD) are less likely to be physically active and have excess weight gain. However, longitudinal studies examining the relationship between DCD and measures of body composition (BMI and waist circumference) over time are lacking. It is not known if sex and physical activity affect the relationship between DCD and measures of body composition over time.(1) To examine if BMI and waist circumference in children with and without probable DCD (pDCD) remain constant over time or change as children age, and whether this relationship varies by sex. (2) To examine if differences in physical activity between children with and without pDCD account for differences in BMI and waist circumference over time.Physical Health Activity Study Team (PHAST) data were used for this longitudinal analysis. At baseline, a total of 2,278 (pDCD = 103) children aged 9-10 years were included in the analysis. The total follow-up period was five years. Mixed-effects modeling was used to estimate change in body composition measures in children over time.Children with pDCD have higher BMI and waist circumference compared to typically developing children, and this difference increased over the study period. The relationship between pDCD and BMI over time also varied by sex. A similar trend was observed for waist circumference. Boys with pDCD were found to have a more rapid increase in BMI and waist circumference compared to girls with pDCD. Physical activity had neither a mediating nor a moderating effect on the relationship between pDCD and measures of body composition. However, physical activity was independently and negatively associated with measures of body composition.pDCD is associated with higher body mass and waist circumference, both important risk factors for cardiovascular disease, type 2 diabetes, and psychological problems and other health conditions.

Objective: Enrollment of individual patients into more than one study has been poorly evaluated. The objective of this study was to describe the characteristics of patients, researchers and centers involved in coenrollment, studies precluding coenrollment, and the prevalence, patterns, predictors, and outcomes of coenrollment in a randomized clinical trial. Design, Setting, Methods: We conducted an observational study nested within the OSCILLation for Acute Respiratory Distress Syndrome Treated Early Trial, which compared high-frequency oscillatory ventilation to conventional ventilation. We collected patient, center, and study data on coenrollment in randomized patients. Multilevel regression examined factors independently associated with coenrollment, considering clustering within centers. We examined the effect of coenrollment on safety and the trial outcome. Interventions None. Measurements and Main Results: Overall, 127 of 548 randomized patients (23.2%) were coenrolled in 25 unique studies. Coenrollment was reported in 17 of 39 centers (43.6%). Patients were most commonly coenrolled in one additional randomized clinical trial (76; 59.8%). Coenrollment was less likely in older patients (odds ratio, 0.87; 95% CI, 0.76–0.997), and in ICUs with greater than 26 beds (odds ratio, 0.56; 95% CI, 0.34–0.94), and more likely by investigators with more than 11 years of experience (odds ratio, 1.73; 95% CI, 1.06–2.82), by research coordinators with more than 8 years of experience (odds ratio, 1.87; 95% CI, 1.11–3.18) and in Canada (odds ratio, 4.66; 95% CI, 1.43–15.15). Serious adverse events were similar between coenrolled high-frequency oscillatory ventilation and control patients. Coenrollment did not modify the treatment effect of high-frequency oscillatory ventilation on hospital mortality. Conclusions: Coenrollment occurred in 23% of patients, commonly in younger patients, in smaller centers with more research infrastructure, and in Canada. Coenrollment did not influence patient safety or trial results.

Autism spectrum disorder (ASD) is characterized by notable phenotypic heterogeneity, which is often viewed as an obstacle to the study of its etiology, diagnosis, treatment, and prognosis. On the basis of empirical evidence, instead of three binary categories, the upcoming edition of the DSM 5 will use two dimensions - social communication deficits (SCD) and fixated interests and repetitive behaviors (FIRB) - for the ASD diagnostic criteria. Building on this proposed DSM 5 model, it would be useful to consider whether empirical data on the SCD and FIRB dimensions can be used within the novel methodological framework of Factor Mixture Modeling (FMM) to stratify children with ASD into more homogeneous subgroups.The study sample consisted of 391 newly diagnosed children (mean age 38.3 months; 330 males) with ASD. To derive subgroups, data from the Autism Diagnostic Interview-Revised indexing SCD and FIRB were used in FMM; FMM allows the examination of continuous dimensions and latent classes (i.e., categories) using both factor analysis (FA) and latent class analysis (LCA) as part of a single analytic framework.Competing LCA, FA, and FMM models were fit to the data. On the basis of a set of goodness-of-fit criteria, a 'two-factor/three-class' factor mixture model provided the overall best fit to the data. This model describes ASD using three subgroups/classes (Class 1: 34%, Class 2: 10%, Class 3: 56% of the sample) based on differential severity gradients on the SCD and FIRB symptom dimensions. In addition to having different symptom severity levels, children from these subgroups were diagnosed at different ages and were functioning at different adaptive, language, and cognitive levels.Study findings suggest that the two symptom dimensions of SCD and FIRB proposed for the DSM 5 can be used in FMM to stratify children with ASD empirically into three relatively homogeneous subgroups.

The purpose of this study was (1) to examine the changes in participation rates over 1 year among children and adolescents after acquired brain injury and (2) to explore the effect of child and family factors on these changes.The participation levels of 136 children and young people (88 males; 48 females; age range 4y 11mo-17y 6mo; mean age 11y 6mo) after acquired brain injury (3≤ Glasgow Coma Scale score ≤15; mean 12.8) were assessed three times: at their return to school, and at 8 and 12 months after returning to school. The Children's Assessment of Participation and Enjoyment measured the participants' diversity and intensity of participation in out-of-school activities. At baseline, information on general family functioning and medical and demographic information was collected as possible predictors. Mixed-effect model analyses of participation scores were performed while controlling for child's age at injury.The severity of the injury explained rates of change across time for participation intensity in recreational, physical, and social activities. Household income influenced changes in the intensity of recreational activities, whereas family functioning predicted changes in the diversity of skill-based activities.Participation is a relevant outcome of recovery that needs to be assessed and monitored post brain injury. Special attention can be directed to severity of injury and family functioning when developing intervention plans.

There are concerns regarding the hazards to the public due to the releases of toxic industrial chemicals (TICs) to the atmosphere as a result of accidents or intentional acts. For recent chlorine railcar accidents, where 30 to 60 tons of pressurized liquefied chlorine were released in rural areas, the number of casualties estimated by several widely-used model systems far exceeded the number of casualties observed, raising concerns by decision makers about the accuracy of the model systems. The comprehensive model system consists of a scenario definition, a source emission model, a transport and dispersion model, an exposure model, and a health risk model. A few of the deficiencies or gaps in the model system are summarized in this paper, including 1) incomplete knowledge of the scenario, 2) uncertainties in the state-of-the-art of source emission models, 3) inadequate transport and dispersion models, 4) limitations of knowledge concerning the population and their movement, and 5) biases and uncertainties in health risk models.

The study examined the utility of the Family Perception of Care Scale (FPCS), which consists of four subscales: resident care, family support, communication, and rooming. This instrument was developed for the purposes of this study. Overall, family members were satisfied with end-of-life care. Satisfaction did not have a statistically significant relationship to family and resident characteristics. Survey questions with the highest number of low satisfaction ratings included staffing levels, updating families and involving them in care planning, and decision making. Family members considered pain control an important priority, followed by comfort care that included caring for a family member with dignity and sensitivity. Family members also valued it when staff were able to inform them that the death of their family member was near. Place of death was significantly associated with satisfaction, family members being more satisfied with end-of-life care when their family member died in the LTC facility as opposed to in hospital.

The focus of the current paper is the Mock Urban Setting Test (MUST) carried out at Dugway Proving Ground. The MUST experiment was designed to represent an urban complex of about 120 buildings with symmetric characteristics. Throughout the 19 day MUST experiment, 63 pu and continuous releases were carried out using propylene as a tracer gas. In order to understand the importance of capturing these spatial variations and unsteadiness, the multipurpose nite element code FEFLO-URBAN was used to perform a Very Large Eddy Simulation (VLES) of MUST. One of the continuous release trials (2682353) was selected for a detailed study. The terrain surface was modeled with geometric roughness in order to circumvent the problem of lack of turbulence production in the vertical direction. The FEFLO-URBAN simulations of the concentrations of the passive tracer were compared with the experimental measurements, resulting in agreement within an order of magnitude about 76% of the time. A study of the sensitivity of the model results with respect to resolution was made with four dieren t mesh resolutions (500K, 4M, 8.1M and 32M elements). A sensitivity study with the wind direction ino w boundary condition was carried out.

Development of gross motor function in children with cerebral palsy (CP) has not been documented. The purposes of this study were to examine a model of gross motor function in children with CP and to apply the model to construct gross motor function curves for each of the 5 levels of the Gross Motor Function Classification System (GMFCS).A stratified sample of 586 children with CP, 1 to 12 years of age, who reside in Ontario, Canada, and are known to rehabilitation centers participated.Subjects were classified using the GMFCS, and gross motor function was measured with the Gross Motor Function Measure (GMFM). Four models were examined to construct curves that described the nonlinear relationship between age and gross motor function.The model in which both the limit parameter (maximum GMFM score) and the rate parameter (rate at which the maximum GMFM score is approached) vary for each GMFCS level explained 83% of the variation in GMFM scores. The predicted maximum GMFM scores differed among the 5 curves (level I=96.8, level II=89.3, level III=61.3, level IV=36.1, and level V=12.9). The rate at which children at level II approached their maximum GMFM score was slower than the rates for levels I and III. The correlation between GMFCS levels and GMFM scores was (.91. Logistic regression, used to estimate the probability that children with CP are able to achieve gross motor milestones based on their GMFM total scores, suggests that distinctions between GMFCS levels are clinically meaningful.Classification of children with CP based on functional abilities and limitations is predictive of gross motor function, whereas age alone is a poor predictor. Evaluation of gross motor function of children with CP by comparison with children of the same age and GMFCS level has implications for decision making and interpretation of intervention outcomes.