Stabilization of 2,6-Diarylanilinum Cation by Through-Space Cation-pi Interactions

Energetically favorable cation-pi interactions play important roles in numerous molecular recognition processes in chemistry and biology. Herein, we present synergistic experimental and computational physical organic chemistry studies on 2,6-diarylanilines that contain flanking meta/parasubstituted aromatic rings adjacent to the central anilinium ion. A combination of measurements of pK(a) values, structural analyses of 2,6-diarylanilinium cations, and quantum chemical analyses based on the quantitative molecular orbital theory and a canonical energy decomposition analysis (EDA) scheme reveal that through-space cation-pi interactions essentially contribute to observed trends in proton affinities and pK(a) values of 2,6-diarylanilines

Local Observations of Climate Change and Adaptation Responses: A Case Study in the Mountain Region of Burundi-Rwanda

Mountain regions and their communities are particularly vulnerable to climate change impacts. However, little is known on the impacts observed and adaptation responses used in Burundi’s mountain region and if these are different to those reported in the contiguous mountain region of Rwanda. This paper aims to fill in these knowledge gaps. Semi-structured interviews were conducted with 300 smallholder farmers, 150 in northern Burundi and 150 in southern Rwanda. Farmers in both countries reported negative impacts on crops, animals, and human health, with small differences between countries driven by the main cultivated crops. More adaptation strategies were used in Burundi than in Rwanda, and more farmers in Burundi were using multiple strategies. In both countries, farmers’ wealth affected farmers’ adaptation responses and their food security. Notably, for all wealth groups (poor, average, rich), food security was lower in Rwanda than in Burundi. We relate our findings to current agricultural intensification policies in both countries and argue for the greater involvement of local farmers in adaptation planning using, for example, science-with-society approaches.We are deeply grateful to our study participants, who graciously shared their time, energy, and stories. We thank our field assistants and facilitators for making this research possible. We also acknowledge the Mountain Research Initiative for funding support

Micro-fabrication of Carbon Structures by Pattern Miniaturization in Resorcinol-Formaldehyde Gel

A simple and novel method to fabricate and miniaturize surface and sub-surface micro-structures and micro-patterns in glassy carbon is proposed and demonstrated. An aqueous resorcinol-formaldehyde (RF) sol is employed for micro-molding of the master-pattern to be replicated, followed by controlled drying and pyrolysis of the gel to reproduce an isotropically shrunk replica in carbon. The miniaturized version of the master-pattern thus replicated in carbon is about one order of magnitude smaller than original master by repeating three times the above cycle of molding and drying. The micro-fabrication method proposed will greatly enhance the toolbox for a facile fabrication of a variety of Carbon-MEMS and C-microfluidic devices.Comment: 16 pages, 5 figure

Slow-spin relaxation of a low-spin S = 1/2 FeIII carborane complex

In this communication, we report the first evidence of slow-spin relaxation of a low-spin FeIII carborane complex. Iron S=1/2 complexes showing such behaviour are specially appealing as qubits candidates because they fulfil some of the main requirements to reach long decoherence times: moderate magnetic anisotropy, small spin, metal element mainly with zero-nuclear spin and furthermore, large versatility to introduce chemical modifications

The class of the locus of intermediate Jacobians of cubic threefolds

We study the locus of intermediate Jacobians of cubic threefolds within the moduli space of complex principally polarized abelian fivefolds, and its generalization to arbitrary genus - the locus of abelian varieties with a singular odd two-torsion point on the theta divisor. Assuming that this locus has expected codimension (which we show to be true for genus up to 5), we compute the class of this locus, and of is closure in the perfect cone toroidal compactification, in the Chow, homology, and the tautological ring. We work out the cases of genus up to 5 in detail, obtaining explicit expressions for the classes of the closures of the locus of products of an elliptic curve and a hyperelliptic genus 3 curve, in moduli of principally polarized abelian fourfolds, and of the locus of intermediate Jacobians in genus 5. In the course of our computation we also deal with various intersections of boundary divisors of a level toroidal compactification, which is of independent interest in understanding the cohomology and Chow rings of the moduli spaces.Comment: v2: new section 9 on the geometry of the boundary of the locus of intermediate Jacobians of cubic threefolds. Final version to appear in Invent. Mat

Cultural keystone species as a tool for biocultural stewardship. A global review

The cultural keystone species (CKS) concept (i.e. ‘species that shape in a major way the cultural identity of a people’ as defined by Garibaldi and Turner in 2004) has been proposed as part of a common framing for the multiple entangled relationships between species and the socioecological systems in which they exist. However, the blurred and prolific definitions of CKS hamper its univocal application. This work examines the current use of the term CKS to reconcile a definition and explore its practical applications for biocultural stewardship. We ran a search for the words ‘cultural’ AND ‘keystone’ AND ‘species’. Our search was limited to peer-reviewed articles published in English between 1994 and 2022 (inclusive) and was conducted using Google Scholar, PubMed, Scopus and Web of Science. We extracted and analysed bibliometric information as well as information on (i) the CKS components, (ii) humans' support for CKS and (iii) the definitions of CKS. From the 313 selected documents, the CKS concept appears to be increasingly accepted, as evidenced by a growing corpus of literature. However, the absence of a systematic and precise way of documenting CKS precludes global cross-cultural comparisons. The geographical distribution of authors using the concept is biased. We found that 47% of all the CKS reported and 38% of the works identified in our review were located in North America. Beyond ‘supporting identity’, several other of nature's contributions to people are associated with the CKS definitions. However, the contributions of the sociocultural group to the survival and conservation of the CKS (i.e. stewardship) are made explicit only in one-third of the documents reviewed. To advance biocultural stewardship as a conservation paradigm, we suggest (a) defining CKS as an indissoluble combination of a non-human species and one or more sociocultural groups; (b) acknowledging that species and sociocultural group relations should be classified in a continuum, according to gradients of relationship intensity; and (c) explicitly acknowledging the reciprocal relationships between sociocultural groups and species. Read the free Plain Language Summary for this article on the Journal blog. © 2024 The Authors. People and Nature published by John Wiley & Sons Ltd on behalf of British Ecological Society.We would like to acknowledge Kelsey Leonard for her contribution to an early draft of this manuscript. G.M. acknowledges funding from the Margarita Salas grant MGSC2022-13. V.R.-G. acknowledges funding from the European Research Council under an ERC Consolidator Grant (FP7-771056-LICCI). R.C.-L. acknowledges funding from the Swiss National Science Foundation Starting Grant (TMSGI3_211659). N.Z.-C. acknowledges that this research is supported by María de Maeztu Excellence Unit 2023-2027 (CEX2021- 001201-M), funded by MCIN/AEI/10.13039/501100011033; and by the Basque Government through the BERC 2022-2025 program. S.D. acknowledges funding from Redes Federales de Alto Impacto MinCyT Argentina (CONVE2023-102072649-APN-MCT). This work contributes to the ‘María de Maeztu’ Programme Excellence Unit of the Spanish Ministry of Science and Innovation (CEX2019-000940-M

Ion Transport across Biological Membranes by Carborane-Capped Gold Nanoparticles

Carborane-capped gold nanoparticles (Au/carborane NPs, 2-3 nm) can act as artificial ion transporters across biological membranes. The particles themselves are large hydrophobic anions that have the ability to disperse in aqueous media and to partition over both sides of a phospholipid bilayer membrane. Their presence therefore causes a membrane potential that is determined by the relative concentrations of particles on each side of the membrane according to the Nernst equation. The particles tend to adsorb to both sides of the membrane and can flip across if changes in membrane potential require their repartitioning. Such changes can be made either with a potentiostat in an electrochemical cell or by competition with another partitioning ion, for example, potassium in the presence of its specific transporter valinomycin. Carborane-capped gold nanoparticles have a ligand shell full of voids, which stem from the packing of near spherical ligands on a near spherical metal core. These voids are normally filled with sodium or potassium ions, and the charge is overcompensated by excess electrons in the metal core. The anionic particles are therefore able to take up and release a certain payload of cations and to adjust their net charge accordingly. It is demonstrated by potential-dependent fluorescence spectroscopy that polarized phospholipid membranes of vesicles can be depolarized by ion transport mediated by the particles. It is also shown that the particles act as alkali-ion-specific transporters across free-standing membranes under potentiostatic control. Magnesium ions are not transported

Accelerated surgery versus standard care in hip fracture (HIP ATTACK): an international, randomised, controlled trial

© 2020 Elsevier Ltd Background: Observational studies have suggested that accelerated surgery is associated with improved outcomes in patients with a hip fracture. The HIP ATTACK trial assessed whether accelerated surgery could reduce mortality and major complications. Methods: HIP ATTACK was an international, randomised, controlled trial done at 69 hospitals in 17 countries. Patients with a hip fracture that required surgery and were aged 45 years or older were eligible. Research personnel randomly assigned patients (1:1) through a central computerised randomisation system using randomly varying block sizes to either accelerated surgery (goal of surgery within 6 h of diagnosis) or standard care. The coprimary outcomes were mortality and a composite of major complications (ie, mortality and non-fatal myocardial infarction, stroke, venous thromboembolism, sepsis, pneumonia, life-threatening bleeding, and major bleeding) at 90 days after randomisation. Patients, health-care providers, and study staff were aware of treatment assignment, but outcome adjudicators were masked to treatment allocation. Patients were analysed according to the intention-to-treat principle. This study is registered at ClinicalTrials.gov (NCT02027896). Findings: Between March 14, 2014, and May 24, 2019, 27 701 patients were screened, of whom 7780 were eligible. 2970 of these were enrolled and randomly assigned to receive accelerated surgery (n=1487) or standard care (n=1483). The median time from hip fracture diagnosis to surgery was 6 h (IQR 4–9) in the accelerated-surgery group and 24 h (10–42) in the standard-care group (p\u3c0·0001). 140 (9%) patients assigned to accelerated surgery and 154 (10%) assigned to standard care died, with a hazard ratio (HR) of 0·91 (95% CI 0·72 to 1·14) and absolute risk reduction (ARR) of 1% (−1 to 3; p=0·40). Major complications occurred in 321 (22%) patients assigned to accelerated surgery and 331 (22%) assigned to standard care, with an HR of 0·97 (0·83 to 1·13) and an ARR of 1% (−2 to 4; p=0·71). Interpretation: Among patients with a hip fracture, accelerated surgery did not significantly lower the risk of mortality or a composite of major complications compared with standard care. Funding: Canadian Institutes of Health Research

Management of Low-Grade Glioma

The optimal management of patients with low-grade glioma (LGG) is controversial. The controversy largely stems from the lack of well-designed clinical trials with adequate follow-up to account for the relatively long progression-free survival and overall survival of patients with LGG. Nonetheless, the literature increasingly suggests that expectant management is no longer optimal. Rather, there is mounting evidence supporting active management including consideration of surgical resection, radiotherapy, chemotherapy, molecular and histopathologic characterization, and use of modern imaging techniques for monitoring and prognostication. In particular, there is growing evidence favoring extensive surgical resection and increasing interest in the role of chemotherapy (especially temozolomide) in the management of these tumors. In this review, we critically analyze emerging trends in the literature with respect to management of LGG, with particular emphasis on reports published during the past year

Comparative phylogenetic methods and the cultural evolution of medicinal plant use

Human life depends on plant biodiversity and the ways in which plants are used are culturally determined. Whilst anthropologists have used phylogenetic comparative methods (PCMs) to gain an increasingly sophisticated understanding of the evolution of political, religious, social, and material culture, plant use has been almost entirely neglected. Medicinal plants are of special interest because of their role in maintaining people’s health across the world. PCMs in particular, and cultural evolutionary theory in general, provide a framework in which to study the diversity of medicinal plant applications cross-culturally, and to infer changes in plant use through time. These methods can be applied to single medicinal plants as well as the entire set of plants used by a culture for medicine, and they account for the non-independence of data when testing for floristic, cultural or other drivers of plant use. With cultural, biological, and linguistic diversity under threat, gaining a deeper and broader understanding of the variation of medicinal plant use through time and space is pressing