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1.
Chemistry ; 30(27): e202301687, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38466912

RESUMO

Spectator ions have known and emerging roles in aqueous metal-cation chemistry, respectively directing solubility, speciation, and reactivity. Here, we isolate and structurally characterize the last two metastable members of the alkali uranyl triperoxide series, the Rb+ and Cs+ salts (Cs-U1 and Rb-U1). We document their rapid solution polymerization via small-angle X-ray scattering, which is compared to the more stable Li+, Na+ and K+ analogues. To understand the role of the alkalis, we also quantify alkali-hydroxide promoted peroxide deprotonation and decomposition, which generally exhibits increasing reactivity with increasing alkali size. Cs-U1, the most unstable of the uranyl triperoxide monomers, undergoes ambient direct air capture of CO2 in the solid-state, converting to Cs4[UVIO2(CO3)3], evidenced by single-crystal X-ray diffraction, transmission electron microscopy, and Raman spectroscopy. We have attempted to benchmark the evolution of Cs-U1 to uranyl tricarbonate, which involves a transient, unstable hygroscopic solid that contains predominantly pentavalent uranium, quantified by X-ray photoelectron spectroscopy. Powder X-ray diffraction suggests this intermediate state contains a hydrous derivative of CsUVO3, where the parent phase has been computationally predicted, but not yet synthesized.

2.
Proc Natl Acad Sci U S A ; 117(5): 2275-2281, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-31941710

RESUMO

Plasmonics now delivers sensors capable of detecting single molecules. The emission enhancements and nanometer-scale optical confinement achieved by these metallic nanostructures vastly increase spectroscopic sensitivity, enabling real-time tracking. However, the interaction of light with such nanostructures typically loses all information about the spatial location of molecules within a plasmonic hot spot. Here, we show that ultrathin plasmonic nanogaps support complete mode sets which strongly influence the far-field emission patterns of embedded emitters and allow the reconstruction of dipole positions with 1-nm precision. Emitters in different locations radiate spots, rings, and askew halo images, arising from interference of 2 radiating antenna modes differently coupling light out of the nanogap, highlighting the imaging potential of these plasmonic "crystal balls." Emitters at the center are now found to live indefinitely, because they radiate so rapidly.

3.
Plant Cell Environ ; 44(12): 3515-3525, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34562029

RESUMO

Environmental heterogeneity is a major driver of plant-microbiome assembly, but the specific climate and soil conditions that are involved remain poorly understood. To better understand plant microbiome formation, we examined the bacteria and fungi that colonize wild strawberry (Fragaria vesca) plants in North American and European populations. Using transects as replicates, we found strong overlap among the environmental conditions that best predict the overall similarity and richness of the plant microbiome, including soil nutrients that replicate across continents. Temperature is also among the main predictors of diversity for both bacteria and fungi in both the leaf and, unexpectedly, the root microbiome. Our results indicate that a small number of environmental factors, and their interactions, consistently contribute to plant microbiome formation, which has implications for predicting the contributions of microbes to plant productivity in ever-changing environments.


Assuntos
Fenômenos Fisiológicos Bacterianos , Meio Ambiente , Fragaria/microbiologia , Fungos/fisiologia , Microbiota , Microbiologia do Solo , Europa (Continente) , América do Norte
4.
Inorg Chem ; 60(3): 1590-1603, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33417450

RESUMO

Coordination numbers and geometries form a theoretical framework for understanding and predicting materials properties. Algorithms to determine coordination numbers automatically are increasingly used for machine learning (ML) and automatic structural analysis. In this work, we introduce MaterialsCoord, a benchmark suite containing 56 experimentally derived crystal structures (spanning elements, binaries, and ternary compounds) and their corresponding coordination environments as described in the research literature. We also describe CrystalNN, a novel algorithm for determining near neighbors. We compare CrystalNN against seven existing near-neighbor algorithms on the MaterialsCoord benchmark, finding CrystalNN to perform similarly to several well-established algorithms. For each algorithm, we also assess computational demand and sensitivity toward small perturbations that mimic thermal motion. Finally, we investigate the similarity between bonding algorithms when applied to the Materials Project database. We expect that this work will aid the development of coordination prediction algorithms as well as improve structural descriptors for ML and other applications.

5.
J Chem Inf Model ; 61(8): 3908-3916, 2021 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-34288678

RESUMO

Surface adsorption is a crucial step in numerous processes, including heterogeneous catalysis, where the adsorption of key species is often used as a descriptor of efficiency. We present here an automated adsorption workflow for semiconductors which employs density functional theory calculations to generate adsorption data in a high-throughput manner. Starting from a bulk structure, the workflow performs an exhaustive surface search, followed by an adsorption structure construction step, which generates a minimal energy landscape to determine the optimal adsorbate-surface distance. An extensive set of energy-based, charge-based, geometric, and electronic descriptors tailored toward catalysis research are computed and saved to a personal user database. The application of the workflow to zinc telluride, a promising CO2 reduction photocatalyst, is presented as a case study to illustrate the capabilities of this method and its potential as a material discovery tool.


Assuntos
Semicondutores , Zinco , Adsorção , Propriedades de Superfície , Fluxo de Trabalho
6.
Heart Lung Circ ; 28(4): e67-e70, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30269872

RESUMO

Arterial cannulation is often challenging in thoracic aortic surgery due to the location of the surgery and need for cerebral protection during periods of circulatory arrest. Cannulation sites including the ascending and descending aorta, axillary, carotid and femoral arteries have limitations and are associated with complications due to their proximity to surrounding structures. Therefore, the innominate artery can be used by either direct cannulation or indirect cannulation via a graft as an alternative site. We present a technique of sole direct innominate artery cannulation that is able to provide both systemic and selective antegrade cerebral perfusion during aortic surgery.


Assuntos
Aneurisma da Aorta Torácica/cirurgia , Dissecção Aórtica/cirurgia , Implante de Prótese Vascular/métodos , Cateterismo/métodos , Circulação Cerebrovascular , Adulto , Idoso , Idoso de 80 Anos ou mais , Dissecção Aórtica/diagnóstico , Dissecção Aórtica/mortalidade , Aneurisma da Aorta Torácica/diagnóstico , Aneurisma da Aorta Torácica/mortalidade , Aortografia , Tronco Braquiocefálico , Feminino , Mortalidade Hospitalar , Humanos , Masculino , Pessoa de Meia-Idade , New South Wales/epidemiologia , Perfusão/métodos
7.
Nano Lett ; 17(8): 4846-4852, 2017 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-28707893

RESUMO

We conducted a comprehensive investigation of dislocations in Al0.46Ga0.54N. Using aberration-corrected scanning transmission electron microscopy and energy dispersive X-ray spectroscopy, the atomic structure and atom distribution at the dislocation core have been examined. We report that the core configuration of dislocations in AlGaN is consistent with that of other materials in the III-Nitride system. However, we observed that the dissociation of mixed-type dislocations is impeded by alloying GaN with AlN, which is confirmed by our experimental observation of Ga and Al atom segregation in the tensile and compressive parts of the dislocations, respectively. Investigation of the optical properties of the dislocations shows that the atom segregation at dislocations has no significant effect on the intensity recorded by cathodoluminescence in the vicinity of the dislocations. These results are in contrast with the case of dislocations in In0.09Ga0.91N where segregation of In and Ga atoms also occurs but results in carrier localization limiting non-radiative recombination at the dislocation. This study therefore sheds light on why InGaN-based devices are generally more resilient to dislocations than their AlGaN-based counterparts.

9.
Plant Cell Environ ; 39(11): 2570-2579, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27487257

RESUMO

The capacity to tolerate freezing temperatures limits the geographical distribution of many plants, including several species of agricultural importance. However, the genes involved in freezing tolerance remain largely unknown. Here, we describe the variation in constitutive freezing tolerance that occurs among worldwide accessions of Arabidopsis thaliana. We found that although plants from high latitudes tend to be more freezing tolerant than plants from low latitudes, the environmental factors that shape cold adaptation differ across the species range. Consistent with this, we found that the genetic architecture of freezing tolerance also differs across its range. Conventional genome-wide association studies helped identify a priori and other promising candidate genes. However, simultaneously modelling climate variables and freezing tolerance together pinpointed other excellent a priori candidate genes. This suggests that if the selective factor underlying phenotypic variation is known, multi-trait mixed models may aid in identifying the genes that underlie adaptation.


Assuntos
Arabidopsis/fisiologia , Congelamento , Estresse Fisiológico , Adaptação Fisiológica , Arabidopsis/genética , Arabidopsis/metabolismo , Estudo de Associação Genômica Ampla , Locos de Características Quantitativas
11.
Nature ; 465(7298): 632-6, 2010 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-20520716

RESUMO

Plants can defend themselves against a wide array of enemies, from microbes to large animals, yet there is great variability in the effectiveness of such defences, both within and between species. Some of this variation can be explained by conflicting pressures from pathogens with different modes of attack. A second explanation comes from an evolutionary 'tug of war', in which pathogens adapt to evade detection, until the plant has evolved new recognition capabilities for pathogen invasion. If selection is, however, sufficiently strong, susceptible hosts should remain rare. That this is not the case is best explained by costs incurred from constitutive defences in a pest-free environment. Using a combination of forward genetics and genome-wide association analyses, we demonstrate that allelic diversity at a single locus, ACCELERATED CELL DEATH 6 (ACD6), underpins marked pleiotropic differences in both vegetative growth and resistance to microbial infection and herbivory among natural Arabidopsis thaliana strains. A hyperactive ACD6 allele, compared to the reference allele, strongly enhances resistance to a broad range of pathogens from different phyla, but at the same time slows the production of new leaves and greatly reduces the biomass of mature leaves. This allele segregates at intermediate frequency both throughout the worldwide range of A. thaliana and within local populations, consistent with this allele providing substantial fitness benefits despite its marked impact on growth.


Assuntos
Alelos , Arabidopsis/genética , Aptidão Genética/genética , Variação Genética/genética , Anquirinas/genética , Anquirinas/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Biomassa , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Estudo de Associação Genômica Ampla , Dados de Sequência Molecular , Fenótipo , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Folhas de Planta/anatomia & histologia , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/parasitologia , Locos de Características Quantitativas
12.
Nature ; 465(7298): 627-31, 2010 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-20336072

RESUMO

Although pioneered by human geneticists as a potential solution to the challenging problem of finding the genetic basis of common human diseases, genome-wide association (GWA) studies have, owing to advances in genotyping and sequencing technology, become an obvious general approach for studying the genetics of natural variation and traits of agricultural importance. They are particularly useful when inbred lines are available, because once these lines have been genotyped they can be phenotyped multiple times, making it possible (as well as extremely cost effective) to study many different traits in many different environments, while replicating the phenotypic measurements to reduce environmental noise. Here we demonstrate the power of this approach by carrying out a GWA study of 107 phenotypes in Arabidopsis thaliana, a widely distributed, predominantly self-fertilizing model plant known to harbour considerable genetic variation for many adaptively important traits. Our results are dramatically different from those of human GWA studies, in that we identify many common alleles of major effect, but they are also, in many cases, harder to interpret because confounding by complex genetics and population structure make it difficult to distinguish true associations from false. However, a-priori candidates are significantly over-represented among these associations as well, making many of them excellent candidates for follow-up experiments. Our study demonstrates the feasibility of GWA studies in A. thaliana and suggests that the approach will be appropriate for many other organisms.


Assuntos
Arabidopsis/classificação , Arabidopsis/genética , Genoma de Planta/genética , Estudo de Associação Genômica Ampla , Fenótipo , Alelos , Proteínas de Arabidopsis/genética , Flores/genética , Genes de Plantas/genética , Loci Gênicos/genética , Genótipo , Imunidade Inata/genética , Endogamia , Polimorfismo de Nucleotídeo Único/genética
13.
Nano Lett ; 15(2): 923-30, 2015 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-25594363

RESUMO

Dislocations are one-dimensional topological defects that occur frequently in functional thin film materials and that are known to degrade the performance of InxGa1-xN-based optoelectronic devices. Here, we show that large local deviations in alloy composition and atomic structure are expected to occur in and around dislocation cores in InxGa(1-x)N alloy thin films. We present energy-dispersive X-ray spectroscopy data supporting this result. The methods presented here are also widely applicable for predicting composition fluctuations associated with strain fields in other inorganic functional material thin films.


Assuntos
Gálio/química , Índio/química , Nitrogênio/química , Microscopia Eletrônica de Transmissão e Varredura , Espectrometria por Raios X
14.
Plant Cell ; 24(12): 4793-805, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23277364

RESUMO

Arabidopsis thaliana is an important model organism for understanding the genetics and molecular biology of plants. Its highly selfing nature, small size, short generation time, small genome size, and wide geographic distribution make it an ideal model organism for understanding natural variation. Genome-wide association studies (GWAS) have proven a useful technique for identifying genetic loci responsible for natural variation in A. thaliana. Previously genotyped accessions (natural inbred lines) can be grown in replicate under different conditions and phenotyped for different traits. These important features greatly simplify association mapping of traits and allow for systematic dissection of the genetics of natural variation by the entire A. thaliana community. To facilitate this, we present GWAPP, an interactive Web-based application for conducting GWAS in A. thaliana. Using an efficient implementation of a linear mixed model, traits measured for a subset of 1386 publicly available ecotypes can be uploaded and mapped with a mixed model and other methods in just a couple of minutes. GWAPP features an extensive, interactive, and user-friendly interface that includes interactive Manhattan plots and linkage disequilibrium plots. It also facilitates exploratory data analysis by implementing features such as the inclusion of candidate polymorphisms in the model as cofactors.


Assuntos
Arabidopsis/genética , Estudo de Associação Genômica Ampla/métodos , Internet , Desequilíbrio de Ligação/genética , Software , Interface Usuário-Computador
15.
PLoS Genet ; 6(2): e1000843, 2010 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-20169178

RESUMO

The population structure of an organism reflects its evolutionary history and influences its evolutionary trajectory. It constrains the combination of genetic diversity and reveals patterns of past gene flow. Understanding it is a prerequisite for detecting genomic regions under selection, predicting the effect of population disturbances, or modeling gene flow. This paper examines the detailed global population structure of Arabidopsis thaliana. Using a set of 5,707 plants collected from around the globe and genotyped at 149 SNPs, we show that while A. thaliana as a species self-fertilizes 97% of the time, there is considerable variation among local groups. This level of outcrossing greatly limits observed heterozygosity but is sufficient to generate considerable local haplotypic diversity. We also find that in its native Eurasian range A. thaliana exhibits continuous isolation by distance at every geographic scale without natural breaks corresponding to classical notions of populations. By contrast, in North America, where it exists as an exotic species, A. thaliana exhibits little or no population structure at a continental scale but local isolation by distance that extends hundreds of km. This suggests a pattern for the development of isolation by distance that can establish itself shortly after an organism fills a new habitat range. It also raises questions about the general applicability of many standard population genetics models. Any model based on discrete clusters of interchangeable individuals will be an uneasy fit to organisms like A. thaliana which exhibit continuous isolation by distance on many scales.


Assuntos
Arabidopsis/genética , Alelos , Cruzamentos Genéticos , Geografia , Haplótipos/genética , Heterozigoto , Endogamia , Dinâmica Populacional
16.
Patterns (N Y) ; 4(8): 100823, 2023 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-37602210

RESUMO

[This corrects the article DOI: 10.1016/j.patter.2023.100723.].

17.
Patterns (N Y) ; 4(5): 100723, 2023 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-37223274

RESUMO

Conventionally, high-throughput computational materials searches start from an input set of bulk compounds extracted from material databases, but, in contrast, many real functional materials are heavily engineered mixtures of compounds rather than single bulk compounds. We present a framework and open-source code to automatically construct and analyze possible alloys and solid solutions from a set of existing experimental or calculated ordered compounds, without requiring additional metadata except crystal structure. As a demonstration, we apply this framework to all compounds in the Materials Project to create a new, publicly available database of >600,000 unique "alloy pair" entries that can be used to search for materials with tunable properties. We exemplify this approach by searching for transparent conductors and reveal candidates that might have been excluded in a traditional screening. This work lays a foundation from which materials databases can go beyond stoichiometric compounds and approach a more realistic description of compositionally tunable materials.

18.
Artigo em Inglês | MEDLINE | ID: mdl-37615693

RESUMO

Video-assisted thoracoscopic sympathicotomy is the most widely used technique in the modern era for the treatment of primary hyperhidrosis. Primary hyperhidrosis is characterized by excessive sweating and significantly affects the quality of life in those who suffer from it. This video tutorial details a uniportal, drainless sympathicotomy performed by the cardiothoracic surgical team at St George Hospital, Sydney, Australia.


Assuntos
Hiperidrose , Qualidade de Vida , Humanos , Hiperidrose/cirurgia
19.
J Pharm Pract ; 36(3): 679-684, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34670427

RESUMO

Background: Contraction alkalosis is characterized by low serum sodium and chloride and high serum carbon dioxide and bicarbonate levels. Case Report: A 28-year-old Caucasian active-duty male with a history of autosomal dominant polycystic kidney disease and diarrhea-predominant Irritable Bowel Syndrome (D-IBS) presented to his primary care provider (PCP) with elevated blood pressure (136/96 mmHg), was diagnosed with stage-2 hypertension, and started oral HCTZ (25 mg/day). His medications included dicyclomine (10 mg oral three times daily). Subsequently, (Visit 1), his blood pressure was 130/91 mmHg and he was started on telmisartan (20 mg/day). At Visit 2, 4 weeks later, his blood pressure improved (121/73 mmHg); however, blood chemistry revealed elevated serum CO2 (32 mEq/L) and chloride (94 mmol/L). Four days later, the patient presented to the Emergency Department with dyspnea and swallowing difficulty. The patient returned to his PCP 3 days later complaining of cough, congestion, vomiting, and mild dyspnea, blood pressure of 124/84 mmHg. Two months later, sudden onset of projectile vomiting and abdominal pain while running was reported, resolved by rehydration and a single oral dose of prochlorperazine 25 mg. Three months later, (Visit 3), he complained of lightheadedness and cloudy judgment, suggesting contraction alkalosis. HCTZ was discontinued and telmisartan was increased to 20 mg twice daily. A follow-up blood chemistry panel 2 weeks later revealed serum chloride and CO2 levels within normal limits and blood pressure under 130/80 mmHg. Conclusion: This is the first known report of contraction alkalosis driven by drug-drug interaction between dicyclomine and HCTZ.


Assuntos
Alcalose , Hipertensão , Humanos , Masculino , Adulto , Telmisartan/farmacologia , Telmisartan/uso terapêutico , Hidroclorotiazida/farmacologia , Hidroclorotiazida/uso terapêutico , Diciclomina/farmacologia , Diciclomina/uso terapêutico , Cloretos/farmacologia , Cloretos/uso terapêutico , Dióxido de Carbono/farmacologia , Dióxido de Carbono/uso terapêutico , Hipertensão/tratamento farmacológico , Pressão Sanguínea , Alcalose/tratamento farmacológico , Anti-Hipertensivos , Quimioterapia Combinada
20.
J Parasitol ; 109(2): 114-128, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-37103005

RESUMO

We herein resurrect and emend PlesiocreadiumWinfield, 1929 (Digenea: Macroderoididae) and provide a supplemental description of its type species, Plesiocreadium typicumWinfield, 1929, based on adult specimens collected from the intestine of bowfins, Amia calva Linnaeus, 1766 (Amiiformes: Amiidae), captured in the L'Anguille River (Mississippi River Basin, Arkansas), Big Lake (Pascagoula River Basin, Mississippi), Chittenango Creek (Oneida Lake, New York), and Reelfoot Lake (Tennessee River Basin, Tennessee). Plesiocreadium spp. (Pl. typicum and Plesiocreadium flavum [Van Cleave and Mueller, 1932] n. comb.) differ from other macroderoidids by having a dorsoventrally flat forebody, ceca that extend posteriad beyond the testes and that do not form a cyclocoel, testes that are greater than one-half of maximum body width, a cirrus sac that is dorsal to the ventral sucker and arches dextrad or sinistrad, a uterine seminal receptacle, asymmetrical vitelline fields that remain separated anteriorly and posteriorly and that extend anteriad to the level of the ventral sucker, and an I-shaped excretory vesicle. Bayesian phylogenetic analyses (ITS2 and 28S) recovered monophyletic Plesiocreadium sensu stricto (as defined herein) sister to Macroderoides trilobatusTaylor, 1978 and that clade sister to the remaining macroderoidids, with sequences ascribed to species of Macroderoides Pearse, 1924 recovered as paraphyletic. We regard Macroderoides parvus (Hunter, 1932) Van Cleave and Mueller, 1934, M. trilobatus, and RauschiellaBabero, 1951 as incertae sedis. Arkansas, New York, and Tennessee comprise new locality records for Pl. typicum.


Assuntos
Trematódeos , Infecções por Trematódeos , Animais , Infecções por Trematódeos/veterinária , Rios , Filogenia , Arkansas , New York , Teorema de Bayes , Tennessee , Trematódeos/genética , Peixes
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