Molecular Main Group Metal Hydrides.

This review serves to document advances in the synthesis, versatile bonding, and reactivity of molecular main group metal hydrides within Groups 1, 2, and 12-16. Particular attention will be given to the emerging use of said hydrides in the rapidly expanding field of Main Group element-mediated catalysis. While this review is comprehensive in nature, focus will be given to research appearing in the open literature since 2001.

Method of micro-sampling human dentine collagen for stable isotope analysis.

RATIONALE: Sampling of dentine for stable carbon (δ13 C) and nitrogen (δ15 N) isotope ratios in the direction of tooth growth allows the study of temporal changes to the diet and physiological stress of an individual during tooth formation. Current methods of sampling permanent teeth using 1 mm increments provide temporal resolution of 6-9 months at best depending on the tooth chosen. Although this gives sufficient sample sizes for reliable analysis by mass spectrometry, sectioning the dentine across the incremental structures results in a rolling average of the isotope ratios. A novel method of incremental dentine collagen sampling has been developed to decrease the collagen increment size to 0.35 mm along the incremental structures, thus reducing averaging and improving the temporal resolution of short-term changes within the δ13 C and δ15 N values. METHODS: This study presents data for a MicroMill-assisted sampling method that allows for sampling at 0.35 mm width × 1 mm depth increments following the incremental growth pattern of dentine. A NewWave MicroMill was used to sample the demineralised dentine section of modern donated human third molars from Sudan and compared to data from the same teeth using the 1 mm incremental sectioning method 2 established by Beaumont et al. RESULTS: The δ13 C and δ15 N isotopic data showed an increased temporal resolution, with each increment providing data for 2-4 months of dentine formation. CONCLUSIONS: The data show the potential of this method for studying dietary reconstruction, nutritional stress, and physiological change with greater temporal resolution potentially to seasonal level and with less attenuation of the δ13 C and δ15 N values than was previously possible from human dentine.

Characteristics of United States military pilots with atrial fibrillation and deployment and retention rates.

INTRODUCTION: Atrial fibrillation (AF) is an arrhythmia that impacts deployment and retention rates for United States military pilots. This study aims to characterize United States active duty (AD) pilots with AF and review deployment and retention rates associated with medical and ablative therapies. METHODS: An observational analysis was performed to assess AD pilots diagnosed with AF in the largest military regional healthcare system from 2004 to 2019. Baseline characteristics and AF management were reviewed. RESULTS: 27 AD pilots (mean age, 37.3 ± 7.9 years; mean BMI, 27.3 ± 3.1 kg/m2; 100% male sex) were diagnosed with AF during the study dates. 17 (63%) were Air Force branch pilots with hypertension as the most common risk factor (26%). There were overall low CHA2DS2-VASc scores (mean 0.29 ± 0.47). 22 (82%) pilots were equally treated with medical rate and rhythm strategies (41% and 41%, respectively). 16 (59%) underwent pulmonary vein isolation (PVI) with zero complications. 11 (41%) pilots received warfarin and 5 (19%) received a direct oral anticoagulant for stroke prevention. After diagnosis, 12 (44%) pilots deployed and 25 (93%) were retained in military. PVI was not associated with a change in subsequent deployments rates (PVI, 38% vs no PVI, 55%; p = 0.3809) or retention rates (PVI, 94% vs no PVI, 91%; p = 0.7835). CONCLUSIONS: United States military pilots diagnosed with AF are younger patients with few traditional AF risk factors and  they receive medical rate and rhythm strategies equally. Many pilots maintain deployment eligibility and most remain on AD status after diagnosis. PVI is not associated with differences in retention or deployment rates. Further prospective study is needed to further evaluate these findings.

Synthesis of Molecular Phenylcalcium Derivatives: Application to the Formation of Biaryls.

Hydrocarbon-soluble ß-diketiminato phenylcalcium derivatives, which display various modes of Ca-µ2 -Ph-Ca bridging, are accessible from reactions of Ph2 Hg and [(BDI)CaH]2 . Although the resultant compounds are inert toward the C-H bonds of benzene, they yield selective and uncatalyzed biaryl formation when reacted with readily available aryl bromides.

Calcium Hydride Reduction of Polycyclic Aromatic Hydrocarbons.

A molecular calcium hydride effects the two electron reduction of polyaromatic hydrocarbons, including naphthalene (E0 =-3.1 V).

A Stable Calcium Alumanyl.

A seven-membered N,N'-heterocyclic potassium alumanyl nucleophile is introduced and utilised in the metathetical synthesis of Mg-Al and Ca-Al bonded derivatives. Both species have been characterised by experimental and theoretical means, allowing a rationalisation of the greater reactivity of the heavier group 2 species implied by an initial assay of their reactivity.

Heterolysis of Dihydrogen by Nucleophilic Calcium Alkyls.

ß-Diketiminato (BDI) calcium alkyl derivatives undergo hydrogenolysis with H2 to regenerate [(BDI)CaH]2 , allowing the catalytic hydrogenation of a wide range of 1-alkenes and norbornene under very mild conditions (2 bar H2 , 298 K). The reactions are deduced to take place with the retention of the dimeric structures of the calcium hydrido-alkyl and alkyl intermediates via a well-defined sequence of Ca-H/C=C insertion and Ca-C hydrogenation events. This latter deduction is strongly supported by DFT calculations (B3PW91) performed on the 1-hexene/H2 system, which also indicates that the hydrogenation transition states display features which discriminate them from a classical σ-bond metathesis mechanism. In particular, NBO analysis identifies a strong second order interaction between the filled α-methylene sp3 orbital of the n-hexyl chain and the σ* orbital of the H2 molecule, signifying that the H-H bond is broken by what is effectively the nucleophilic displacement of hydride by the organic substituent.

Ancient human genome sequence of an extinct Palaeo-Eskimo.

We report here the genome sequence of an ancient human. Obtained from approximately 4,000-year-old permafrost-preserved hair, the genome represents a male individual from the first known culture to settle in Greenland. Sequenced to an average depth of 20x, we recover 79% of the diploid genome, an amount close to the practical limit of current sequencing technologies. We identify 353,151 high-confidence single-nucleotide polymorphisms (SNPs), of which 6.8% have not been reported previously. We estimate raw read contamination to be no higher than 0.8%. We use functional SNP assessment to assign possible phenotypic characteristics of the individual that belonged to a culture whose location has yielded only trace human remains. We compare the high-confidence SNPs to those of contemporary populations to find the populations most closely related to the individual. This provides evidence for a migration from Siberia into the New World some 5,500 years ago, independent of that giving rise to the modern Native Americans and Inuit.

Archaeological, radiological, and biological evidence offer insight into Inca child sacrifice.

Examination of three frozen bodies, a 13-y-old girl and a girl and boy aged 4 to 5 y, separately entombed near the Andean summit of Volcán Llullaillaco, Argentina, sheds new light on human sacrifice as a central part of the Imperial Inca capacocha rite, described by chroniclers writing after the Spanish conquest. The high-resolution diachronic data presented here, obtained directly from scalp hair, implies escalating coca and alcohol ingestion in the lead-up to death. These data, combined with archaeological and radiological evidence, deepen our understanding of the circumstances and context of final placement on the mountain top. We argue that the individuals were treated differently according to their age, status, and ritual role. Finally, we relate our findings to questions of consent, coercion, and/or compliance, and the controversial issues of ideological justification and strategies of social control and political legitimation pursued by the expansionist Inca state before European contact.

Alkaline-Earth-Catalyzed Dehydrocoupling of Amines and Boranes.

Dehydrocoupling reactions between the boranes HBpin and 9-borabicyclo[3.3.1]nonane and a range of amines and anilines ensue under very mild reaction conditions in the presence of a simple ß-diketiminato magnesium n-butyl precatalyst. The facility of the reactions is suggested to be a function of the Lewis acidity of the borane substrate, and is dictated by resultant pre-equilibria between, and the relative stability of, magnesium hydride and borohydride intermediates during the course of the catalysis.

Neural network-based reconstruction of steady-state temperature systems with unknown material composition.

Effective thermal management is crucial for the performance and longevity of devices such as computer chips and batteries. A fundamental challenge in this field is accurately determining temperature distributions, which are often limited by incomplete observations. We introduce a neural-network-based approach to overcome these challenges. Specifically, a physics-informed fully convolutional auto-encoder coupled with a preceding spatial propagator network module is used to reconstruct complete temperature fields from partial observations, without requiring additional information about the spatial distribution of materials with varying thermal properties. This paper details the development and validation of our model, demonstrating its effectiveness in virtual sensing setups for both simulated and real-world thermal systems. The reconstruction capabilities for different sampling strategies are investigated. The most challenging of which is the "grid-edge" sampling where only discrete temperature sensors on the periphery of the systems are taken as input, amounting to a sampling ratio as low as 3.12%. The presented method is able to reconstruct the full temperature field with a relative average error of 1.1%. The NN-based approach outperforms the standard Kriging method in predicting the maximum temperature in a system, and proves more robust when the available measurements contain little information.

Temporal trends in anticoagulation management for US active duty personnel with atrial fibrillation.

ObjectivesThis study aims to investigate US active duty (AD) military members diagnosed with atrial fibrillation (AF) and the temporal trends of systemic anticoagulation (AC). Our secondary objective is to study the AC prescriptions in AD military members diagnosed with AF and associated military dispositions and deployment rates. DESIGN AND SETTING: A retrospective investigation of Tricare pharmacy AC prescriptions within the San Antonio Military Health System from January 2004 to July 2019 for AD individuals diagnosed with AF was performed. PARTICIPANTS: 386 AD personnel with non-valvular AF were analysed (mean age 35.0±9.4 years; mean body mass index, 28.3±4.3 kg/m2; 93% male; 57% Caucasian, 94% paroxysmal AF). OUTCOMES: The temporal trends of systemic AC prescriptions were the primary outcome measures. The association between AC prescriptions and military dispositions and deployments were secondary outcomes of interest. STATISTICAL ANALYSIS: The association between AC management, future deployments and military disposition was analysed using χ2 and Fisher's exact test for categorical variables. The t-test was used for comparison of continuous variables. RESULTS: CHA2DS2-VASc and HAS-BLED scores were low (0.39±0.65 and 0.86±0.63, respectively). 127 (33%) members received warfarin and 58 (15%) received direct oral anticoagulants (DOACs). Rates of military retention were not different between AC histories (no AC (64%) vs warfarin (75%) vs DOAC (65%); p=0.425). There was a significant trend of more recent utilisation of DOACs compared with warfarin (p<0.0001). When adjusted for temporal changes in deployment rates, there was no significant difference in deployment between AC groups (no AC (39%) vs warfarin (49%) vs DOAC (27%); p=0.9472). CONCLUSIONS: This is the first report describing AC utilisation in US AD military members with AF. Young AD personnel with low stroke and bleeding risks do not commonly receive AC prescriptions. DOAC prescription rates are increasing and predominate over warfarin for AC indications.

A Review of the Collagen Orientation in the Articular Cartilage.

OBJECTIVE: There has been a debate as to the alignment of the collagen fibers. Using a hand lens, Sir William Hunter demonstrated that the collagen fibers ran perpendicular and later aspects were supported by Benninghoff. Despite these 2 historical studies, modern technology has conflicting data on the collagen alignment. DESIGN: Ten mature New Zealand rabbits were used to obtain 40 condyle specimens. The specimens were passed through ascending grades of alcohol, subjected to critical point drying (CPD), and viewed in the scanning electron microscope. Specimens revealed splits from the dehydration process. When observing the fibers exposed within the opening of the splits, parallel fibers were observed to run in a radial direction, normal to the surface of the articular cartilage, radiating from the deep zone and arcading as they approach the surface layer. After these observations, the same samples were mechanically fractured and damaged by scalpel. RESULTS: The splits in the articular surface created deep fissures, exposing parallel bundles of collagen fibers, radiating from the deep zone and arcading as they approach the surface layer. On higher magnification, individual fibers were observed to run parallel to one another, traversing radially toward the surface of the articular cartilage and arcading. Mechanical fracturing and scalpel damage induced on the same specimens with the splits showed randomly oriented fibers. CONCLUSION: Collagen fiber orientation corroborates aspects of Hunter's findings and compliments Benninghoff. Investigators must be aware of the limits of their processing and imaging techniques in order to interpret collagen fiber orientation in cartilage.

Vasculitis integrated clinical assessment database: a data management system to support studies into systemic vasculitis.

BACKGROUND: The systemic vasculitides are characterized by immune inflammation affecting blood vessels, which can lead to organ and tissue damage. Treatment has improved but optimum long-term management still remains unsatisfactory, requiring ongoing therapeutic studies. These often base their measures of efficacy on the outcome of clinical assessments which include the Birmingham Vasculitis Activity Score and the Vasculitis Damage Index. OBJECTIVES: Efficient management of assessment data is complex and often hampered by working with time-consuming paper-based systems. The Vasculitis Integrated Clinical Assessment Database (VICAD) was created to improve the process. METHODS: VICAD was developed using Microsoft Access. Visual Basic for Applications and the Data Access Objects Application Programming Interface provide the functionality to assist with scoring, calculation of results, and storing of data. RESULTS: VICAD is an efficient system for managing data. Evaluation of its use showed an improvement in the completeness of patient assessments from 77% (paper based: n = 44) to 98% (computer based: n = 30). During development clinicians (n = 4) rated it at 8/10 for its layout and visual presentation and 8/10 for easy to use (intuitiveness and navigability). CONCLUSIONS: The development of an integrated and standardized system of data collection (VICAD) helps to support clinical decision making processes and report findings in a more timely manner. It is available free for use and modification under the GNU General Public License. The open source nature of VICAD could help to inform the design of other databases where management of complex information into important multisystem diseases is needed.

Primary Cardiac Lymphoma Manifesting as Complete Heart Block.

Primary cardiac tumors are exceedingly rare with variable clinical manifestations. This case involves a patient presentation of symptomatic complete heart block and cardiac imaging revealing a right atrial mass invading the myocardium consistent with Burkitt lymphoma on histopathology. The patient received definitive bradytherapy with a pacemaker and chemotherapy for the primary cardiac lymphoma. After three cycles of chemotherapy, the right atrial mass regressed significantly with restoration of atrioventricular conduction and no pacing burden. Primary cardiac lymphomas infrequently manifest as atrioventricular block and this case highlights cardiac masses as a potential etiology when evaluating new conduction disturbances and bradyarrhythmias.

Active Duty Personnel With ST Elevation Myocardial Infarctions Are Deployment Ineligible Despite Receiving Standard Management.

INTRODUCTION: ST elevation myocardial infarction (STEMI) is a high acuity diagnosis that requires prompt recognition and developed system responses to reduce morbidity and mortality. There is a paucity of literature describing active duty (AD) military personnel with STEMI syndromes at military treatment facilities (MTFs). This study aims to describe AD military members with STEMI diagnoses, military treatment facility management, and subsequent military dispositions observed. MATERIALS AND METHODS: We performed a single-center, retrospective review of all STEMI diagnoses at San Antonio Military Medical Center (SAMMC) from January 2008 to June 2018. Patients met inclusion in the analysis if they were (1) AD personnel in the United States Air Force (USAF) or United States Army (USA) and (2) presented with electrocardiogram findings and cardiac biomarkers diagnostic of a STEMI diagnosis. ASCVD and STEMI diagnoses were confirmed by board certified interventional cardiologists with coronary angiography. The 2017 American College of Cardiology (ACC) STEMI clinical performance and quality measures were used as the standard of care metrics for our case reviews. RESULTS: A total of 236 patients were treated for STEMI at SAMMC during the study period. Eight (3.4%) of these cases met inclusion criteria of being AD status at the time of diagnosis. Five (63%) of the AD STEMI diagnoses were USA members, three (37%) were USAF members, 50% were Caucasian, and 100% were male sex. The average age and body mass index were 46.3 ± 5.5 years old and 28.5 ± 3.1 kg/m 2, respectively. Preexisting cardiovascular risk factors were present in six (75%) of the individuals with hypertension being most common (63%). The eight patients had a baseline average low-density lipoprotein cholesterol of 110 ± 39 mg/dL, total cholesterol of 180 ± 49 mg/dL and calculated 10-year risk of atherosclerotic cardiovascular disease (ASCVD) 3.9 ± 1.6%. 100% of patients underwent primary percutaneous coronary intervention (PCI) within 90 minutes of presentation (average door-to-balloon time 59.3 ± 24 min). Single-vessel disease was found in all eight patients and seven of them underwent drug-eluting stent placement (average number of stents 2 ± 1.5). Performance and quality measures were met in all applicable categories including door-to-balloon times, discharge medical therapies, and cardiac rehabilitation enrollments for 100% AD personnel. Reported adverse events included two stent thromboses and two vascular complications. Three of eight individuals (37.5%) were diagnosed with behavioral health disorders secondary to their acute coronary syndrome. Medical retirement secondary to STEMI diagnosis occurred in 87.5% of subjects and all study personnel medically retired within 24 months (average 12.8 ± 7.9 months). CONCLUSIONS: AD personnel represent a small minority of MTF STEMI diagnoses and present with lower risk cardiovascular profiles. AD personnel received standard STEMI management compared to national performance measures, and were deployment ineligible after STEMI diagnoses. Further studies are needed to definitively explore the appropriate military dispositions for members with STEMI diagnoses and acute coronary syndromes.

Histology and Raman spectroscopy of limed human remains from the Rwandan Genocide.

The Murambi Genocide Memorial Centre is one of the major centres in Rwanda that commemorate the 1994 Rwandan genocide. Seventeen months after the genocide, about 1000 excavated human remains were put on display in Murambi Technical School. Repeated efforts were made to desiccate the human remains with lime for educational reasons. The aim of this study was to assess their state of preservation and understand the extent of degradation of the tissue. Limed soft tissue samples from four individuals were examined with light and electron microscopy, and subjected to histological analysis. Raman spectroscopy at 785 nm and 1064 nm provided information about the impact of environmental conditions on the extent of deterioration to these samples, the presence of organics and the conversion of the associated lime from calcium hydroxide to calcium carbonate. While visual degradation of the bodies in Murambi has been reported, this study confirms deterioration at a microscopic and molecular level. Both histology and Raman spectroscopic analysis revealed that the limed bodies in Murambi were deteriorating at the time the samples were collected. The results of this study will inform future decisions regarding the long-term conservation of those human remains.

Reductive dehydrocoupling of diphenyltin dihydride with LiAlH4: selective synthesis and structures of the first bicyclo[2.2.1]heptastannane-1,4-diide and bicyclo[2.2.2]octastannane-1,4-diide.

The reaction of diphenyltin dihydride with LiAlH4 gives access to a set of charged tin cages as their lithium salts. Variation in the ratio of reactants provides a perstannabicyclooctane dianion and a perstannanorbornane as the di- and monoanions. These compounds can be synthesised selectively by careful stoichiometric control and have been characterised by single crystal X-ray diffractometry, NMR and UV-vis spectroscopy. Computational exploration of the electronic structures of these compounds was undertaken and, in agreement with structural and spectroscopic features, indicated significant σ-delocalisation in the tin skeletons.

A Stable Calcium Alumanyl.

A seven-membered N,N'-heterocyclic potassium alumanyl nucleophile is introduced and utilised in the metathetical synthesis of Mg-Al and Ca-Al bonded derivatives. Both species have been characterised by experimental and theoretical means, allowing a rationalisation of the greater reactivity of the heavier group 2 species implied by an initial assay of their reactivity.

Using evidence from hair and other soft tissues to infer the need for and receipt of health-related care provision.

The Bioarchaeology of Care approach developed by Tilley is usually applied to skeletalized human remains, given the usual constraints of preservation bias that are seen with archaeological assemblages. However, other tissues, such as hair are sometimes preserved and can provide a wealth of information that can supplement the skeletal data. Archaeological hair has been analysed for drug compounds for almost thirty years. This article integrates data from hair analyses for coca metabolites, stable light isotope analysis and aDNA to expand the potential of the Bioarchaeology of Care approach using the example of a spontaneously mummified adult female from northern Chile.