Thermal decomposition of cyclohexane by flash pyrolysis vacuum ultraviolet photoionization time-of-flight mass spectrometry: a study on the initial unimolecular decomposition mechanism.

Thermal decomposition of cyclohexane at temperatures up to 1310 K was performed using flash pyrolysis coupled with vacuum ultraviolet (118.2 nm) photoionization time-of-flight mass spectrometry. The experimental results revealed that the major initiation reaction of cyclohexane decomposition was C-C bond fission leading to the formation of 1,6-hexyl diradical. The 1,6-hexyl diradical could isomerize to 1-hexene and decompose into ˙C3H7 + ˙C3H5 and ˙C4H7 + ˙C2H5. The 1,6-hexyl diradical could also undergo direct dissociation; the C4H8 fragment via the 1,4-butyl diradical intermediate was observed, serving as evidence of the 1,6-hexyl diradical mechanism. Quantum chemistry calculations at UCCSD(T)/cc-pVDZ level of theory on the initial reaction pathways of cyclohexane were performed and found to be consistent with the experimental conclusions. Cyclohexyl radical was not observed as an initial intermediate in the pyrolysis. Benzene was produced from sequential H2 eliminations of cyclohexane at high temperatures.

Flash Pyrolysis of t-Butyl Hydroperoxide and Di-t-butyl Peroxide: Evidence of Roaming in the Decomposition of Organic Hydroperoxides.

Thermal decomposition of t-butyl hydroperoxide and di-t-butyl peroxide was investigated using flash pyrolysis (in a short reaction time of <100 µs) and vacuum-ultraviolet (λ = 118.2 nm) single-photon ionization time-of-flight mass spectrometry (VUV-SPI-TOFMS) at temperatures up to 1120 K and quantum computational methods. Acetone and methyl radical were detected as the predominant products in the initial decomposition of di-t-butyl peroxide via O-O bond fission. In the initial dissociation of t-butyl hydroperoxide, acetone, methyl radical, isobutylene, and isobutylene oxide products were identified. The novel detection of the unimolecular formation of isobutylene oxide, as supported by the computational study, was found to proceed via a roaming hydroxyl radical facilitated by a hydrogen-bonded intermediate. This new pathway could provide a new class of reactions to consider in the modeling of the low temperature oxidation of alkanes.

A 25-Year Overview of AgrAbility Demographics.

The U.S. Department of Agriculture's (USDA) National Institute of Food and Agriculture (NIFA) AgrAbility Program was established as part of the 1990 Farm Bill. It functions through partnerships between land grant universities and nonprofit disability organizations to improve the independence and quality of life of ranchers and farmers with disabilities. This article reports on analyses of the first 25 years of demographic data from clients served by funded state AgrAbility projects.Between 1991 and 2016, State or Regional AgrAbility Projects (SRAPs) provided information, education, and service annually to an estimated average of 490 new clients for a total of 11,754 new clients. New clients' average age was 52.1 with 75.1% male. Primary causes of reported disabilities were chronic nonincident-related disabilities (41.7%), non-agricultural incidents (32.2%), and agricultural incidents (19.5%). Typically AgrAbility served clients for one to 74 months (M = 14.85 months), because of the severity of their disabilities, the deterioration of their situation, and the years it sometimes took to assist them in reaching their goals. Combining new, ongoing, reopened, and closed case reports, SRAPs served approximately 1,190 clients annually on average. The average age of new, ongoing, reopened, and closed case reports was 52.7 with 78.0% male.Data collection, analyses, and reporting of client data presented a means of providing program accountability and of helping guide future programming efforts. Findings were used by stakeholders, policymakers, and decision-makers to justify the continued inclusion of the AgrAbility Program in the 2018 USDA Farm Bill.

Which U.S. medical graduates plan to become specialty-board certified? Analysis of the 1997-2004 national association of American Medical Colleges Graduation Questionnaire database.

BACKGROUND: Predictors of U.S. allopathic medical-school graduates' board-certification plans have not been characterized. METHOD: Using multivariable logistic regression, graduates' responses to 11 questions on the 1997-2004 Association of American Medical Colleges Graduation Questionnaire were analyzed to identify independent predictors of plans for specialty-board certification. RESULTS: The proportion of 108,408 graduates planning specialty-board certification decreased from 97.3% in 1997 to 88.4% in 2004. Among 101,805 (93.9%) graduates with complete data, graduates who were Hispanic, rated their clinical clerkships, quality of medical education, and confidence in clinical skills more highly, had any debt, and planned "University-faculty" careers were more likely to plan becoming board certified. Females, Asians/Pacific Islanders, and graduates who planned to practice in underserved areas, planned "other" nonclinical-practice careers, and graduated with MD/other (non-PhD) degrees were less likely to plan becoming board certified. CONCLUSION: Specialty-board certification does not appear to be among the professional goals for a growing proportion of U.S. medical graduates.

Twenty years of AgrAbility: a retrospective forum.

In 1990, the Farm Bill included authorization for the Education and Training Assistance Program for Farmers with Disabilities with the goal of enabling a high-quality lifestyle for farmers, ranchers, and other agricultural workers with disabilities. Twenty years later, AgrAbility is a developed national program with 25 state projects and affiliates throughout the United States and strong recognition with the rural and disability communities. A special forum was held in Washington, DC, last September to celebrate AgrAbility's achievements. Clients, staff members, advisory team members, government officials, and guests joined to discuss future plans for the program. Recommendations were considered to broaden the effect of the program and to enhance access to program services, especially in states without funded programs. This article summarizes key outcomes from this event.

AgrAbility mental/behavioral health for farm/ranch families with disabilities.

Farmers and their families are at high risk for work-related stressors and incidents that may result in physically disabling conditions. Coping with the acute and chronic results of disability has been documented to contribute to mental and behavioral health issues. Improvements in the ability to cope with the impact of stressors and adjustment to living with a severe disability can enhance quality of life and well-being and decrease long-term emotional complications. Due to the unique characteristics of many rural or agricultural communities (including isolation, low population density, and lack of transportation services), residents with disabilities are at significant risk for mental/behavioral health issues complicated by the lack of mental/behavioral health services and resources. The United States Department of Agriculture (USDA) AgrAbility Program was authorized by Congress as part of the 1990 Farm Bill to assist farmers, ranchers, their workers, and families who are impacted by disability. Initially AgrAbility services targeted physical disabilities; but as the need has become more apparent, efforts are being made to expand mental/behavioral health-related services, including referrals to appropriate sources of treatment. A survey was conducted in 2009 by the National AgrAbility Project (NAP) to identify the types of mental/behavioral health services and resources that the 21 USDA-funded State and Regional AgrAbility Projects (SRAPs) provide for their clients. Resources were also identified from three other experts in the rural mental/behavioral health field who are associated with the AgrAbility Program. The purpose of this article is to report a summary of those services and resources that are currently available through the AgrAbility network. Recommendations for the NAP concerning mental/behavioral health initiatives and implementation strategies for the SRAPs are also presented.

Estimating the prevalence of disability within the U.S. farm and ranch population.

A review of literature was conducted on farm and ranch population estimates, the prevalence of disability in that group, and the effect of disease and injury on that disability rate. Methods used by various entities (primarily governmental) to estimate the population and disability prevalence among farmers, ranchers, family members, and other agricultural workers are summarized. A systematic methodology was developed to combine results from the most recent surveys and censuses and was used to make best estimates of the agricultural population impacted by disability. The findings show that estimates of the disability population in the farm, ranch, and agricultural labor sector, ranges from 1.04 million to 2.23 million individuals depending upon which surveys and censuses are used. Primary reasons identified for the inability to provide a more precise population size include lack of consistent survey methodologies and definitions. A strong argument can be made for additional efforts to determine a more accurate value for the number of individuals in the farm and ranch population who would benefit from disability services, as well as a more accurate estimate of the total population directly involved in agricultural production. Without such data, calculation of more reliable exposure levels to injury and disability is not possible.

Farm-related injuries among Old Order Anabaptist children: developing a baseline from which to formulate and assess future prevention strategies.

Old Order Anabaptists are a religiously based North American subculture that is often identified with simple lifestyles, limited reliance on modern technologies, and unique farming methods, including dependence upon horse-drawn vehicles and farm equipment. Members of this group generally have large numbers of children and begin involving them in work around the home or farm at an early age. Children are called upon to participate in a wide range of activities that most farm children are no longer exposed to due to the adoption of modern technologies and changing roles of children in contemporary society. Preliminary research suggested that farm-related injuries and fatalities may be an increasing problem among Old Order Anabaptist children, thus posing the need for a better understanding of causative factors, which could then contribute to the design of more effective intervention strategies. This present study employed a national injury surveillance process to expand Purdue University's Old Order Anabaptist Injury Database in order to develop a baseline of Old Order child-related farm injury information for the year 2002 and then analyzed that data in reference to specific underlying factors. From the expanded database, 217 farm-related injuries to children under the age of 18 from 14 states and Canada were identified as having occurred during the year 2002. The most common primary source of injury was falls, and the most common nature of injury was bone fractures. The age of victim most commonly reported was 14, with the peaks in injuries occurring at ages 3-4 and 13-15. Culture-specific factors played a role in many of the incidents, the main ones being direct animal contact, hay-hole falls, and horse-drawn equipment runovers. Fourteen of the 217 recorded injuries resulted in fatalities, of which 6 were attributed to equipment runovers and the rest to a crush or pin, a fall, being struck by an object, direct animal contact, or engulfment in feed/grain. Animal behavior was cited as the secondary source of injury in 6 of the fatality cases. Based upon the findings of this study, a body of recommendations was developed for formulating culturally sensitive childhood injury prevention strategies in Old Order communities for use by parents, Old Order parochial school teachers, employers, extension educators, health workers, and others. Those recommendations focus specifically on resources and actions for each group involved as well as on possible topics for further research. The baseline data also provides a means to assess the impact of future injury prevention efforts targeting the Old Order population.