A Stable Anionic Dithiolene Radical.

Sulfurization of anionic N-heterocyclic dicarbene, [:C{[N(2,6-PrCH)]CHCLi}] (2), with elemental sulfur (in a 1:2 ratio) in EtO at low temperature gives 3 by inserting two sulfur atoms into the Li-C (i.e., C2 and C4) bonds in polymeric 2.

Structural Distortions Accompanying Noncovalent Interactions: Methane-Water, the Simplest C-H Hydrogen Bond.

Neglect of fragment structural distortions resulting from noncovalent interactions is a common practice when examining a potential energy surface (PES). Herein, we make quantitative predictions concerning the magnitude of such distortions in the methane-water system. Coupled cluster methods up to perturbative quadruples [CCSDT(Q)] were used in the structural optimizations to the complete basis set limit (using up to cc-pV6Z basis sets).

Bees of the Azores: an annotated checklist (Apidae, Hymenoptera).

We report 18 species of wild bees plus the domesticated honeybee from the Azores, which adds nine species to earlier lists. One species, , seems to be a single island endemic, and three species are possibly native (, , and ). All the remaining bee species are most likely accidental introductions that arrived after human colonization of the archipelago in the 15 century.

A2 to B Blood Type Incompatible Deceased Donor Kidney Transplantation in a Recipient Infected with the Human Immunodeficiency Virus: A Case Report.

Background: With the introduction of the Kidney Allocation System in the United States in December 2014, transplant centers can list eligible B blood type recipients for A2 organ offers. There have been no prior reports of ABO incompatible A2 to B deceased donor kidney transplantation in human immunodeficiency virus-positive (HIV+) recipients to guide clinicians on enrolling or performing A2 to B transplantations in HIV+ candidates. We are the first to report a case of A2 to B deceased donor kidney transplantation in an HIV+ recipient with good intermediate-term results.

Thioformaldehyde S-Sulfide, Sulfur Analogue of the Criegee Intermediate: Structures, Energetics, and Rovibrational Analysis.

The ephemeral Criegee intermediate, first postulated over 70 years ago, has only recently been isolated in the gas phase. The sulfur analogue of this canonical zwitterion, thioformaldehyde S-sulfide, has eluded similar analysis; however, argon matrix isolation has been achieved ( Angew. Chem.

Older candidates for kidney transplantation: Who to refer and what to expect?

The number of older end-stage renal disease patients being referred for kidney transplantation continues to increase. This rise is occurring alongside the continually increasing prevalence of older end-stage renal disease patients. Although older kidney transplant recipients have decreased patient and graft survival compared to younger patients, transplantation in this patient population is pursued due to the survival advantage that it confers over remaining on the deceased donor waiting list.

Limited Dispersal and Significant Fine - Scale Genetic Structure in a Tropical Montane Parrot Species.

Tropical montane ecosystems are biodiversity hotspots harbouring many endemics that are confined to specific habitat types within narrow altitudinal ranges. While deforestation put these ecosystems under threat, we still lack knowledge about how heterogeneous environments like the montane tropics promote population connectivity and persistence. We investigated the fine-scale genetic structure of the two largest subpopulations of the endangered El Oro parakeet (Pyrrhura orcesi) endemic to the Ecuadorian Andes.

Infrared laser spectroscopy of the n-propyl and i-propyl radicals: Stretch-bend Fermi coupling in the alkyl CH stretch region.

The n-propyl and i-propyl radicals were generated in the gas phase via pyrolysis of n-butyl nitrite [CH(CH)ONO] and i-butyl nitrite [(CH)CHCHONO], respectively. Nascent radicals were promptly solvated by a beam of He nanodroplets, and the infrared spectra of the radicals were recorded in the CH stretching region. Several previously unreported bands are observed between 2800 and 3150 cm.

The Symmetric Exchange Reaction OH + HO → HO + OH: Convergent Quantum Mechanical Predictions.

The symmetric hydrogen exchange reaction OH + HO → HO + OH has been studied using the "gold standard" CCSD(T) method with the correlation-consistent basis sets up to aug-cc-pV5Z. The CCSDT and CCSDT(Q) methods were used for the final energic predictions. Two entrance complexes and two transition states on the HO potential surface were located.

Characterization of guinea pig T cell responses elicited after EP-assisted delivery of DNA vaccines to the skin.

The skin is an ideal target tissue for vaccine delivery for a number of reasons. It is highly accessible, and most importantly, enriched in professional antigen presenting cells. Possessing strong similarities to human skin physiology and displaying a defined epidermis, the guinea pig is an appropriate model to study epidermal delivery of vaccine.

CO reduction with Re(i)-NHC compounds: driving selective catalysis with a silicon nanowire photoelectrode.

The CO-reduction activity of two Re(i)-NHC complexes is investigated employing a silicon nanowire photoelectrode to drive catalysis. Photovoltages greater than 440 mV are observed along with excellent selectivity towards CO over H formation. The observed selectivity towards CO production correlates with strong adsorption of the catalysts on the photoelectrode surface.

Decline in territory size and fecundity as a response to carrying capacity in an endangered songbird.

Density-dependent processes are fundamental mechanisms for the regulation of populations. Ecological theories differ in their predictions on whether increasing population density leads to individual adjustments of survival and reproductive output or to dominance and monopolization of resources. Here, we use a natural experiment to examine which factors limit population growth in the only remaining population of the endangered pale-headed brush finch (Atlapetes pallidiceps).

Investigating the ground-state rotamers of n-propylperoxy radical.

The n-propylperoxy radical has been described as a molecule of critical importance to studies of low temperature combustion. Ab initio methods were used to study this three-carbon alkylperoxy radical, normal propylperoxy. Reliable CCSD(T) (coupled-cluster theory, incorporating single, double, and perturbative triple)/ANO0 geometries were predicted for the molecule's five rotamers.

Energetics and transition-state dynamics of the F + HOCH → HF + OCH reaction.

The F + HOCH → HF + OCH reaction is a system with 15 internal degrees of freedom that can provide a benchmark for the development of theory for increasingly complex chemical reactions. The dynamics of this reaction were studied by photoelectron-photofragment coincidence (PPC) spectroscopy carried out on the F(HOCH) anion, aided by a computational study of both the anion and neutral potential energy surfaces, with energies extrapolated to the CCSDT(Q)/CBS level of theory. Photodetachment at 4.

Geographical distance and barriers explain population genetic patterns in an endangered island perennial.

Island plants are frequently used as model systems in evolutionary biology to understand factors that might explain genetic diversity and population differentiation levels. Theory suggests that island plants should have lower levels of genetic diversity than their continental relatives, but this hypothesis has been rejected in several recent studies. In the Azores, the population level genetic diversity is generally low.

Mn-NHC Electrocatalysts: Increasing π Acidity Lowers the Reduction Potential and Increases the Turnover Frequency for CO Reduction.

A new manganese(I) N-heterocyclic carbene electrocatalyst containing a benzimidazole-pyrimidine-based ligand is reported for the two-electron conversion of CO. The increased π acidity of pyrimidine shifts the two-electron reduction to -1.77 V vs Fc/Fc, 70 mV more positive than that for MnBr(2,2'-bipyridine)(CO); increased catalytic current enhancement is also observed (5.

Spin-Adapted Formulation and Implementation of Density Cumulant Functional Theory with Density-Fitting Approximation: Application to Transition Metal Compounds.

Density cumulant functional theory (DCT) has recently emerged as an attractive ab initio approach for the treatment of electron correlation. In its orbital-optimized formulation (ODC-12) [J. Chem.

The Kidney Transplant Evaluation Process in the Elderly: Reasons for Being Turned down and Opportunities to Improve Cost-Effectiveness in a Single Center.

Background. The kidney transplant evaluation process for older candidates is complex due to the presence of multiple comorbid conditions. Methods.

Biodiversity at multiple trophic levels is needed for ecosystem multifunctionality.

Many experiments have shown that loss of biodiversity reduces the capacity of ecosystems to provide the multiple services on which humans depend. However, experiments necessarily simplify the complexity of natural ecosystems and will normally control for other important drivers of ecosystem functioning, such as the environment or land use. In addition, existing studies typically focus on the diversity of single trophic groups, neglecting the fact that biodiversity loss occurs across many taxa and that the functional effects of any trophic group may depend on the abundance and diversity of others.

Early and Sustained Reduction in Donor-Specific Antibodies in Desensitized Living Donor Kidney Transplant Recipients: A 3-Year Prospective Study.

Background: Desensitization with IVIG and rituximab allows acceptable graft survival in sensitized kidney transplant recipients with preexisting donor-specific antibodies (DSAs) and a positive crossmatch. There is little published data reporting the durability of DSA removal in kidney transplant recipients treated with IVIG and rituximab.

Methods: We conducted a 3-year prospective DSA monitoring study in living donor kidney recipients with preexisting DSA to assess the durability of DSA removal after a perioperative protocol of IVIG and rituximab.

Push-Pull Stabilization of Parent Monochlorosilylenes.

While reaction of carbene-stabilized disilicon L:Si═Si:L (L: = C{N(2,6-(i)Pr2C6H3)CH}2) (8) with HCl·NC5H5 results in carbene-stabilized Si2Cl2 (2) and substituted 1H-imidazole (9), combination of the corresponding Fe(CO)4-modified disilicon carbene complex L:Si═Si[Fe(CO)4]:L (6) with pyridine hydrochloride gives a species containing two push-pull-stabilized parent monochlorosilylenes that are bridged by an Fe(CO)3 unit (7). The nature of 7 was further elucidated by spectroscopic, crystallographic, and computational methods. Spectroscopic data suggest that 7 exists as two diastereoisomers.

Percutaneous Endoscopic Gastrostomy in Direct Puncture Technique: When, Why and How?

Background: Percutaneous endoscopic gastrostomy (PEG) placed in the pull through (PT) technique is a common procedure to restore enteral feeding in patients with swallowing disorders. Limitations of this technique are patients with obstruction of the pharynx or esophagus or with an esophageal stent. We report our experience with the direct puncture (DP) PEG device.

Floral colour change as a potential signal to pollinators.

Colour change in flowers (with age and/or after pollination) is taxonomically widespread, has evolved repeatedly, and has a range of putative selective benefits linked to modifying pollinator behaviour; however, this phenomenon seems paradoxically uncommon. We explore this paradox by reviewing the empirical evidence and argue that the evolution and maintenance of floral colour change as a signal to modify pollinator behaviour require special ecological circumstances that will often not be met across a plant population for a sustained number of generations, which potentially explains the scarcity of this phenomenon. We discuss alternative explanations for floral colour change and potentially fruitful lines of future research.

Electrophilic Aromatic Substitution: New Insights into an Old Class of Reactions.

The classic SEAr mechanism of electrophilic aromatic substitution (EAS) reactions described in textbooks, monographs, and reviews comprises the obligatory formation of arenium ion intermediates (σ complexes) in a two-stage process. Our findings from several studies of EAS reactions challenge the generality of this mechanistic paradigm. This Account focuses on recent computational and experimental results for three types of EAS reactions: halogenation with molecular chlorine and bromine, nitration by mixed acid (mixture of nitric and sulfuric acids), and sulfonation with SO3.

Forests of opportunities and mischief: disentangling the interactions between forests, parasites and immune responses.

Habitat characteristics determine the presence of individuals through resource availability, but at the same time, such features also influence the occurrence of parasites. We analyzed how birds respond to changes in interior forest structures, to forest management regimes, and to the risk of haemosporidian infections. We captured and took blood samples from blackcaps (Sylvia atricapilla) and chaffinches (Fringilla coelebs) in three different forest types (beech, mixed deciduous, spruce).