Vibrational Spectroscopic Study of the Cocrystal Products Formed by Cinchona Alkaloids with 5-Nitrobarbituric Acid

X-ray powder diffraction, differential scanning calorimetry, infrared absorption spectroscopy, and Raman spectroscopy have been used to study the phenomenon of cocrystal formation in the molecular complexes formed by 5-nitrobarbituric acid with four cinchona alkaloids. The cocrystal products were found to contain varying degrees of hydration, ranging from no hydration in the nitrobarbiturate-quinidine cocrystal up to a 4.5-hydrate species in the nitrobarbiturate-cinchonine cocrystal. For the nitrobarbiturate cocrystals with cinchonine, cinchonidine, and quinidine, the predominant interaction was with the quinoline ring system of the alkaloid. However, for quinine, the predominant interaction was with the quinuclidine group of the alkaloid. These properties serve to demonstrate the utility of 5-nitrobarbituric acid as a preferred reagent for chemical microscopy, since the differing range of hydrate and structural types would serve to easily differentiate the cinchona alkaloids from each other, even when different compounds contained the same absolute configurations at their dissymmetric centers

Subsonic high-angle-of-attack aerodynamic characteristics of a cone and cylinder with triangular cross sections and a cone with a square cross section

Experiments were conducted in the 12-Foot Pressure Wind Tunnel at Ames Research Center on three models with noncircular cross sections: a cone having a square cross section with rounded corners and a cone and cylinder with triangular cross sections and rounded vertices. The cones were tested with both sharp and blunt noses. Surface pressures and force and moment measurements were obtained over an angle of attack range from 30 deg to 90 deg and selected oil-flow experiments were conducted to visualize surface flow patterns. Unit Reynolds numbers ranged from 0.8x1,000,000/m to 13.0x1,000,000/m at a Mach number of 0.25, except for a few low-Reynolds-number runs at a Mach number of 0.17. Pressure data, as well as force data and oil-flow photographs, reveal that the three dimensional flow structure at angles of attack up to 75 deg is very complex and is highly dependent on nose bluntness and Reynolds number. For angles of attack from 75 deg to 90 deg the sectional aerodynamic characteristics are similar to those of a two dimensional cylinder with the same cross section

Structural Properties, Order-Disorder Phenomena and Phase Stability of Orotic Acid Crystal Forms

Orotic acid (OTA) is reported to exist in the anhydrous (AH), monohydrate (Hy1) and dimethylsulfoxide monosolvate (SDMSO) forms. In this study we investigate the (de)hydration/desolvation behavior, aiming at an understanding of the elusive structural features of anhydrous OTA by a combination of experimental and computational techniques, namely, thermal analytical methods, gravimetric moisture (de)sorption studies, water activity measurements, X-ray powder diffraction, spectroscopy (vibrational, solid-state NMR), crystal energy landscape and chemical shift calculations. The Hy1 is a highly stable hydrate, which dissociates above 135°C and loses only a small part of the water when stored over desiccants (25°C) for more than one year. In Hy1, orotic acid and water molecules are linked by strong hydrogen bonds in nearly perfectly planar arranged stacked layers. The layers are spaced by 3.1 Å and not linked via hydrogen-bonds. Upon dehydration the X-ray powder diffraction and solid-state NMR peaks become broader indicating some disorder in the anhydrous form. The Hy1 stacking reflection (122) is maintained, suggesting that the OTA molecules are still arranged in stacked layers in the dehydration product. Desolvation of SDMSO, a non-layer structure, results in the same AH phase as observed upon dehydrating Hy1. Depending on the desolvation conditions different levels of order-disorder of layers present in anhydrous OTA are observed, which is also suggested by the computed low energy crystal structures. These structures provide models for stacking faults as intergrowth of different layers is possible. The variability in anhydrate crystals is of practical concern as it affects the moisture dependent stability of AH with respect to hydration

Accretion variability of Herbig Ae/Be stars observed by X-Shooter. HD 31648 and HD 163296

This work presents X-Shooter/VLT spectra of the prototypical, isolated Herbig Ae stars HD 31648 (MWC 480) and HD 163296 over five epochs separated by timescales ranging from days to months. Each spectrum spans over a wide wavelength range covering from 310 to 2475 nm. We have monitored the continuum excess in the Balmer region of the spectra and the luminosity of twelve ultraviolet, optical and near infrared spectral lines that are commonly used as accretion tracers for T Tauri stars. The observed strengths of the Balmer excesses have been reproduced from a magnetospheric accretion shock model, providing a mean mass accretion rate of 1.11 x 10^-7 and 4.50 x 10^-7 Msun yr^-1 for HD 31648 and HD 163296, respectively. Accretion rate variations are observed, being more pronounced for HD 31648 (up to 0.5 dex). However, from the comparison with previous results it is found that the accretion rate of HD 163296 has increased by more than 1 dex, on a timescale of ~ 15 years. Averaged accretion luminosities derived from the Balmer excess are consistent with the ones inferred from the empirical calibrations with the emission line luminosities, indicating that those can be extrapolated to HAe stars. In spite of that, the accretion rate variations do not generally coincide with those estimated from the line luminosities, suggesting that the empirical calibrations are not useful to accurately quantify accretion rate variability.Comment: 14 pages, 7 Figures, Accepted in Ap

Preventable suicides involving medicines: a systematic case series of coroners' reports in england and wales.

Background: In England and Wales coroners have a duty to write a report, called a Prevention of Future Deaths report or PFD, when they believe that actions should be taken to prevent future deaths. Coroners send PFDs to individuals and organisations who are required to respond within 56 days. Despite the increase in mental health concerns and growing use of medicines, deaths reported by coroners that have involved medicine-related suicides had not yet been explored. Therefore, this study aimed to systematically assess coroners’ PFD reports involving suicides in which a medicine caused or contributed to the death to identify lessons for suicide prevention. Methods: Using the Preventable Deaths Tracker database https://preventabledeathstracker.net/), 3037 coroners’ PFD reports in England and Wales were screened for eligibility between July 2013 and December 2019. Reports were included if they involved suicide or intentional self-harm and prescribed or over-the-counter medication; illicit drugs were excluded. Following data extraction, descriptive statistics, document and content analysis were performed to assess coroners’ concerns and the recipients of reports. Results: There were 734 suicide-related coroner reports, with 100 (14%) reporting a medicine. Opioids (40%) were the most common class involved, followed by antidepressants (30%). There was wide geographical variation in the writing of reports; coroners in Manchester wrote the most (18%). Coroners expressed 237 concerns; the most common were procedural inadequacies (14%, n = 32), inadequate documentation and communication (10%, n = 22), and inappropriate prescription access (9%, n = 21). 203 recipients received the PFDs, with most sent to NHS trusts (31%), clinical commissioning groups (10%), and general practices (10%), of which only 58% responded to the coroner. Conclusions: One in four coroner reports in England and Wales involved suicides, with one in seven suiciderelated deaths involving a medicine. Concerns raised by coroners highlighted gaps in care that require action from the Government, health services, and prescribers to aid suicide prevention. Coroner reports should be routinely used and monitored to inform public health policy, disseminated nationally, and responses to coroners should be transparently enforced so that actions are taken to prevent future suicides

RENAL HOMOGRAFTS IN PATIENTS WITH MAJOR DONOR-RECIPIENT BLOOD GROUP INCOMPATIBILITIES.

Between November 24, 1962, and May 15, 1963, 12 renal homografts were done at the University of Colorado Medical Center. In half of the cases, a kidney was provided by a donor of the same major blood type as the recipient. In the other half, the major blood groups of the donor and recipient patients were different. The present study is concerned with an analysis of the results in these comparative series, in order to determine what influence the presence or absence of major blood group compatibility had upon the early success rate