Zeolite-Catalyzed Isobutene Amination: Mechanism and Kinetics

Amination of isobutene with NH was investigated over Brønsted acidic zeolites at 1 atm and 453-483 K. To compare catalytic activities over different zeolites, the measured reaction rates are normalized by the number of active sites determined by tert-butylamine temperature-programmed desorption (TPD). Small- A nd medium-pore zeolites with one-dimensional channels exhibit low activity because of pore blockage by adsorbed tert-butylammonium ions. However, turnover frequencies and activation energies are not sensitive to framework identity, as long as the active site is accessible to isobutene and tert-butylamine. Kinetic measurements and FTIR spectroscopy reveal that the Brønsted acid sites in MFI are covered predominantly with tert-butylammonium ions under reaction conditions. The desorption of tert-butylamine is assisted by the concurrent adsorption of isobutene. DFT simulations show that at very low tert-butylamine partial pressures, for example, at the inlet to the reactor, tert-butylamine desorption is rate-limiting. However, at sufficiently high tert-butylamine partial pressures (>0.03 kPa), protonation of isobutene to the corresponding carbenium ion limits the rate of amination.

Gestational age at delivery and special educational need: retrospective cohort study of 407,503 schoolchildren

<STRONG>Background</STRONG> Previous studies have demonstrated an association between preterm delivery and increased risk of special educational need (SEN). The aim of our study was to examine the risk of SEN across the full range of gestation. <STRONG>Methods and Findings</STRONG> We conducted a population-based, retrospective study by linking school census data on the 407,503 eligible school-aged children resident in 19 Scottish Local Authority areas (total population 3.8 million) to their routine birth data. SEN was recorded in 17,784 (4.9%) children; 1,565 (8.4%) of those born preterm and 16,219 (4.7%) of those born at term. The risk of SEN increased across the whole range of gestation from 40 to 24 wk: 37–39 wk adjusted odds ratio (OR) 1.16, 95% confidence interval (CI) 1.12–1.20; 33–36 wk adjusted OR 1.53, 95% CI 1.43–1.63; 28–32 wk adjusted OR 2.66, 95% CI 2.38–2.97; 24–27 wk adjusted OR 6.92, 95% CI 5.58–8.58. There was no interaction between elective versus spontaneous delivery. Overall, gestation at delivery accounted for 10% of the adjusted population attributable fraction of SEN. Because of their high frequency, early term deliveries (37–39 wk) accounted for 5.5% of cases of SEN compared with preterm deliveries (<37 wk), which accounted for only 3.6% of cases. <STRONG>Conclusions</STRONG> Gestation at delivery had a strong, dose-dependent relationship with SEN that was apparent across the whole range of gestation. Because early term delivery is more common than preterm delivery, the former accounts for a higher percentage of SEN cases. Our findings have important implications for clinical practice in relation to the timing of elective delivery

Optical Trapping of an Ion

For several decades, ions have been trapped by radio frequency (RF) and neutral particles by optical fields. We implement the experimental proof-of-principle for trapping an ion in an optical dipole trap. While loading, initialization and final detection are performed in a RF trap, in between, this RF trap is completely disabled and substituted by the optical trap. The measured lifetime of milliseconds allows for hundreds of oscillations within the optical potential. It is mainly limited by heating due to photon scattering. In future experiments the lifetime may be increased by further detuning the laser and cooling the ion. We demonstrate the prerequisite to merge both trapping techniques in hybrid setups to the point of trapping ions and atoms in the same optical potential.Comment: 5 pages, 3 figure

A Prospective Longitudinal Study of the Clinical Outcomes from Cryptococcal Meningitis following Treatment Induction with 800 mg Oral Fluconazole in Blantyre, Malawi

Introduction: Cryptococcal meningitis is the most common neurological infection in HIV infected patients in Sub Saharan Africa, where gold standard treatment with intravenous amphotericin B and 5 flucytosine is often unavailable or difficult to administer. Fluconazole monotherapy is frequently recommended in national guidelines but is a fungistatic drug compromised by uncertainty over optimal dosing and a paucity of clinical end-point outcome data. Methods: From July 2010 until March 2011, HIV infected adults with a first episode of cryptococcal meningitis were recruited at Queen Elizabeth Central Hospital, Blantyre, Malawi. Patients were treated with oral fluconazole monotherapy 800 mg daily, as per national guidelines. ART was started at 4 weeks. Outcomes and factors associated with treatment failure were assessed 4, 10 and 52 weeks after fluconazole initiation. Results: Sixty patients were recruited. 26/60 (43%) died by 4 weeks. 35/60 (58.0%) and 43/56 (77%) died or failed treatment by 10 or 52 weeks respectively. Reduced consciousness (Glasgow Coma Score ,14 of 15), moderate/severe neurological disability (modified Rankin Score .3 of 5) and confusion (Abbreviated Mental Test Score ,8 of 10) were all common at baseline and associated with death or treatment failure. ART prior to recruitment was not associated with better outcomes. Conclusions: Mortality and treatment failure from cryptococcal meningitis following initiation of treatment with 800 mg oral fluconazole is unacceptably high. To improve outcomes, there is an urgent need for better therapeutic strategies and point-of-care diagnostics, allowing earlier diagnosis before development of neurological deficit

Microbial ligand costimulation drives neutrophilic steroid-refractory asthma

Funding: The authors thank the Wellcome Trust (102705) and the Universities of Aberdeen and Cape Town for funding. This research was also supported, in part, by National Institutes of Health GM53522 and GM083016 to DLW. KF and BNL are funded by the Fonds Wetenschappelijk Onderzoek, BNL is the recipient of an European Research Commission consolidator grant and participates in the European Union FP7 programs EUBIOPRED and MedALL. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Equipment preferences of men and women employed in early childhood education

During the last four decades early childhood educators have stressed the importance of male workers entering the occupation. Claims have been made that both children and programs benefit from the presence of male caregivers. However, the actual percentage of men working with young children is very small and has not increased. While professionals have accepted, as a matter of faith, that the presence of male workers is beneficial, no empirical data support this claim. Research efforts have failed to document unique male contributions to the early childhood environment. The current study suggests that previous studies may have been measuring the wrong variables. The current study measured the different equipment and supply preferences of men and women working in the field of early childhood education. Participants were each given a booklet with 50 pictures of daycare equipment and supplies and requested to choose 15 items that they would like to use to supplement an already equipped classroom. A panel had previously rated these items on a 5 point scale from very feminine to very masculine. Participants were also requested to complete an education and experience survey as well as a Sex Role Preference scale

A survey of protectionism from import quotas

It is the purpose of this paper to analyze the contributions to the theory of protectionism from import quotas and to compare quota protection with tariff protection. Partial and general equilibrium analysis are used to compare the effects of quotas on consumption, production, and income distribution with tariffs and free trade. Edgeworth boxes are used to determine the effects of quotas on trade in a pure exchange model. Tariffs and quotas are found 'equivalent' in the static context of both partial and general equilibrium analysis. By 'equivalent' we mean both can be used to produce identical results with respect to prices, production, consumption and income distribution. The 'equivalence' breaks down in the dynamic context due to the different adjustment mechanisms of the two systems. Quotas are shown to adjust to shifting markets through changes in relative prices while adjustment under the tariff takes place through changes in the quantities traded. In the dynamic partial equilibrium model we find the quota more protective than the tariff in the 'tightening' market and less protective in the 'softening' market. Our findings in the 'tightening' market contradict the historical reliance on tariffs in markets with inelastic demand. In the 'softening' market context the use of tariffs is found valid

No new snow to cover the snow: two stories

This thesis is comprised of two pieces of fiction. Each takes place in the fictional Hinge County, North Carolina. The first story, "Winter, Keep Us Warm," deals with the themes of fear and desire, and how they intertwine with one another. The second story, "Oh, What a Foretaste," is much longer than the first, and may be considered a novella. It explores the various relationships between faith, family, community, identity, and geography

UNDERSTANDING EXECUTIVE TURNOVER: EXECUTIVE PERFORMANCE AND ECONOMIC CHANGES

Previous studies examining the predictors of turnover have focused on lower-level employees rather than executives in the upper-ranks of the organization. The few studies that have examined executive turnover have failed to differentiate turnover that results from individual decisions (i.e., voluntary turnover) and organizational decisions (i.e., involuntary turnover). Applying Crossan, Vera, and Nanjad’s (2008) transcendent leadership framework and a new moderator variable I call “recession awareness”, the current study explores the relationships of executive performance and economic changes with executive-level voluntary and involuntary turnover. Using a sample of 523 executives in a large financial institution over an 18 month period, the present study attempted to: (1) analyze the relationships between executive performance and turnover, both voluntary and involuntary, and (2) to investigate changes in the relationships between these variables across different economic situations. While the study suffered from measurement issues which inhibited the interpretation of analyses, a consistent negative relationship was found between executive performance and involuntary turnover. In addition, some initial support was provided for the use of recession awareness as a moderator for the relationship of executive performance and turnover. The implications of these findings and suggestions for future research are discussed

All this splendor: three stories

These stories explore the vulnerabilities of three distinct characters; each of them young and struggling with the isolation and loneliness that besets us when we feel like we don't "fit in." Like most of us, they want an easy answer, a simple solution to patch up wounds and move on. Life is rarely so simple. In these stories, they begin to open their eyes to the complexity of the world as well as its wonder