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1.
bioRxiv ; 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39314330

RESUMO

Errors in proteostasis, which requires regulated degradation and recycling of diverse proteins, are linked to aging, cancer and neurodegenerative disease (1). In particular, recycling proteins from multiprotein complexes, organelles and membranes is initiated by ubiquitylation, extraction and unfolding by the essential mechanoenzyme VCP (2-4), and ubiquitin removal by deubiquitinases (DUBs), a class of ∼100 ubiquitin-specific proteases in humans (5, 6). As VCP's substrate recognition requires ubiquitylation, the removal of ubiquitins from substrates for recycling must follow extraction and unfolding. How the activities of VCP and different DUBs are coordinated for protein recycling or other fates is unclear. Here, we employ a photochemistry-based approach to profile proteome-wide domain-specific VCP interactions in living cells (7). We identify DUBs that bind near the entry, exit, or both sites of VCP's central pore, the channel for ATP-dependent substrate translocation (8-10). From this set of DUBs, we focus on VCPIP1, required for organelle assembly and DNA repair (11-13), that our chemical proteomics workflow indicates binds the central pore's entry and exit sites. We determine a ∼3Šcryo-EM structure of the VCP-VCPIP1 complex and find up to 3 VCPIP1 protomers interact with the VCP hexamer. VCPIP1's UBX-L domain binds VCP's N-domain in a 'down' conformation, linked to VCP's ADP-bound state (2, 14), and the deubiquitinase domain is positioned at the central pore's exit site, poised to remove ubiquitin following substrate unfolding. We find that VCP stimulates VCPIP1's DUB activity and use mutagenesis and single-molecule mass photometry assays to test the structural model. Together, our data suggest that DUBs bind VCP at distinct sites and reveal how the two enzyme activities can be coordinated to achieve specific downstream outcomes for ubiquitylated proteins.

2.
Plant Genome ; : e20512, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39295194

RESUMO

Wheat (Triticum aestivum L.) production must be doubled in the next 25 years to meet the global food demand. Harvest index (HI) is an important indicator of efficient partitioning of photosynthetic assimilates to grains. Reducing competition from alternative sinks, such as stems, and deviating assimilates toward grain increase grain number (GN), HI, and grain yield (GY). Novel partitioning traits have great potential to be utilized in wheat breeding programs to increase HI. In this study, we evaluated 236 US facultative soft wheat genotypes for multiple stem and spike partitioning traits at 7 days after anthesis, and for GN, HI, and GY in two locations of Florida in 2016-2017 and 2017-2018 wheat growing seasons. The panel was genotyped with 20,706 single nucleotide polymorphisms generated by genotype-by-sequencing approach. Spike partitioning index (SPI) showed negative significant correlations with lamina partitioning index and true stem partitioning index. Internode 2 and 3 lengths and partitioning indices had significant negative correlations with SPI and HI. The results indicate enhanced competition for assimilates between spikes and second and third internodes during stem elongation. Genome-wide association study (GWAS) identified 114 unique significant marker-trait associations (MTAs) for 12 traits, and 58 MTAs were found within genes that encode different proteins related to biotic/abiotic stress tolerance and other functions. Significant MTAs identified in the GWAS were converted into kompetitive allele specific PCR markers. Some of the markers were validated and can be effectively employed in marker-assisted selection to improve HI, GY, and GN.

3.
Glob Chang Biol ; 30(8): e17440, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39185562

RESUMO

The use of plant genetic resources (PGR)-wild relatives, landraces, and isolated breeding gene pools-has had substantial impacts on wheat breeding for resistance to biotic and abiotic stresses, while increasing nutritional value, end-use quality, and grain yield. In the Global South, post-Green Revolution genetic yield gains are generally achieved with minimal additional inputs. As a result, production has increased, and millions of hectares of natural ecosystems have been spared. Without PGR-derived disease resistance, fungicide use would have easily doubled, massively increasing selection pressure for fungicide resistance. It is estimated that in wheat, a billion liters of fungicide application have been avoided just since 2000. This review presents examples of successful use of PGR including the relentless battle against wheat rust epidemics/pandemics, defending against diseases that jump species barriers like blast, biofortification giving nutrient-dense varieties and the use of novel genetic variation for improving polygenic traits like climate resilience. Crop breeding genepools urgently need to be diversified to increase yields across a range of environments (>200 Mha globally), under less predictable weather and biotic stress pressure, while increasing input use efficiency. Given that the ~0.8 m PGR in wheat collections worldwide are relatively untapped and massive impacts of the tiny fraction studied, larger scale screenings and introgression promise solutions to emerging challenges, facilitated by advanced phenomic and genomic tools. The first translocations in wheat to modify rhizosphere microbiome interaction (reducing biological nitrification, reducing greenhouse gases, and increasing nitrogen use efficiency) is a landmark proof of concept. Phenomics and next-generation sequencing have already elucidated exotic haplotypes associated with biotic and complex abiotic traits now mainstreamed in breeding. Big data from decades of global yield trials can elucidate the benefits of PGR across environments. This kind of impact cannot be achieved without widescale sharing of germplasm and other breeding technologies through networks and public-private partnerships in a pre-competitive space.


Assuntos
Segurança Alimentar , Melhoramento Vegetal , Doenças das Plantas , Triticum , Triticum/genética , Triticum/microbiologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Resistência à Doença/genética , Pandemias , Fungicidas Industriais , Meio Ambiente
4.
Front Plant Sci ; 15: 1388881, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39119506

RESUMO

Introduction: Wheat grain filling processes under post-anthesis stress scenarios depend mainly on stem traits and remobilization of stem water-soluble carbohydrates (WSC). Methods: A diverse panel of advanced semi-dwarf spring wheat lines, representing a natural variation in stem traits (WSC content, stem diameter, peduncle length, and stem wall width), was used to identify specific traits that reliably reflect the relationship between WSC and grain yield. The panel was phenotyped under various environmental conditions: well-watered, water-limited, and heat stress in Mexico, and terminal-drought in Israel. Results: Environmental stresses reduced grain yield (from 626 g m-2 under well-watered to 213 g m-2 under heat), lower internode diameter, and peduncle length. However, stem-WSC generally peaked 3-4 weeks after heading under all environmental conditions except heat (where it peaked earlier) and expressed the highest values under water-limited and terminal-drought environments. Increased investment in internode diameter and peduncle length was associated with a higher accumulation of stem WSC, which showed a positive association with yield and kernel weight. Across all environments, there were no apparent trade-offs between increased crop investment in internode diameter, peduncle length, and grain yield. Discussion: Our results showed that selecting for genotypes with higher resource investment in stem structural biomass, WSC accumulation, and remobilization could be a valuable strategy to ameliorate grain size reduction under stress without compromising grain yield potential. Furthermore, easy-to-measure proxies for WSC (stem diameter at specific internodes and length of the last internode, i.e., the peduncle) could significantly increase throughput, potentially at the breeding scale.

5.
bioRxiv ; 2024 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-39185238

RESUMO

Cells mechanically interface with their surroundings through cytoskeleton-linked adhesions, allowing them to sense physical cues that instruct development and drive diseases such as cancer. Contractile forces generated by myosin motor proteins mediate these mechanical signal transduction processes through unclear protein structural mechanisms. Here, we show that myosin forces elicit structural changes in actin filaments (F-actin) that modulate binding by the mechanosensitive adhesion protein α-catenin. Using correlative cryo-fluorescence microscopy and cryo-electron tomography, we identify F-actin featuring domains of nanoscale oscillating curvature at cytoskeleton-adhesion interfaces enriched in zyxin, a marker of actin-myosin generated traction forces. We next introduce a reconstitution system for visualizing F-actin in the presence of myosin forces with cryo-electron microscopy, which reveals morphologically similar superhelical F-actin spirals. In simulations, transient forces mimicking tugging and release of filaments by motors produce spirals, supporting a mechanistic link to myosin's ATPase mechanochemical cycle. Three-dimensional reconstruction of spirals uncovers extensive asymmetric remodeling of F-actin's helical lattice. This is recognized by α-catenin, which cooperatively binds along individual strands, preferentially engaging interfaces featuring extended inter-subunit distances while simultaneously suppressing rotational deviations to regularize the lattice. Collectively, we find that myosin forces can deform F-actin, generating a conformational landscape that is detected and reciprocally modulated by a mechanosensitive protein, providing a direct structural glimpse at active force transduction through the cytoskeleton.

6.
Drug Alcohol Depend ; 262: 111394, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39024798

RESUMO

OBJECTIVES: In November 2019, the Massachusetts legislature passed An Act Modernizing Tobacco Control and became the first state to restrict retail sales of all flavored (including menthol) cigarettes, e-cigarettes, and other tobacco products (the Act). Additional tobacco control policies and health insurance coverage for tobacco treatment were included as part of the Act. Implementation of these policies occurred between November 2019 and June 2020. This study explored challenges and facilitators during the implementation of the Act experienced by public health officials, school personnel, and healthcare providers. METHODS: We conducted in-depth interviews with a purposive sample of 9 public health officials and advocates, 9 school personnel, and 8 healthcare providers from March to December 2021. We conducted thematic analysis of interview transcripts using inductive codes of key themes emerging from the interviews. RESULTS: Interviewees highlighted three key themes that impacted the implementation of the Act: 1) Education of those impacted by the Act, 2) Organizational-level changes to incorporate the Act, and 3) Enforcement challenges. Examples of challenges to the implementation of the Act included COVID-19 pandemic restrictions, navigating tobacco industry tactics around naming flavors, and confusion regarding health insurance coverage for tobacco use cessation programs. Examples of facilitators were enforcement leading to retailer compliance, committed advocacy efforts of leadership/champions, and strong coordination within and between organizations. CONCLUSIONS: These findings of Massachusetts's experience in policy implementation can inform the preparation to implement similar tobacco control policies in other states.


Assuntos
Comércio , Aromatizantes , Produtos do Tabaco , Humanos , Massachusetts , Produtos do Tabaco/economia , Produtos do Tabaco/legislação & jurisprudência , Indústria do Tabaco/legislação & jurisprudência , COVID-19/epidemiologia , COVID-19/prevenção & controle , Sistemas Eletrônicos de Liberação de Nicotina , Saúde Pública , Pessoal de Saúde
7.
Nat Plants ; 10(7): 1081-1090, 2024 07.
Artigo em Inglês | MEDLINE | ID: mdl-38965400

RESUMO

Increasing global food demand will require more food production1 without further exceeding the planetary boundaries2 while simultaneously adapting to climate change3. We used an ensemble of wheat simulation models with improved sink and source traits from the highest-yielding wheat genotypes4 to quantify potential yield gains and associated nitrogen requirements. This was explored for current and climate change scenarios across representative sites of major world wheat producing regions. The improved sink and source traits increased yield by 16% with current nitrogen fertilizer applications under both current climate and mid-century climate change scenarios. To achieve the full yield potential-a 52% increase in global average yield under a mid-century high warming climate scenario (RCP8.5), fertilizer use would need to increase fourfold over current use, which would unavoidably lead to higher environmental impacts from wheat production. Our results show the need to improve soil nitrogen availability and nitrogen use efficiency, along with yield potential.


Assuntos
Mudança Climática , Fertilizantes , Nitrogênio , Triticum , Triticum/crescimento & desenvolvimento , Triticum/metabolismo , Fertilizantes/análise , Nitrogênio/metabolismo , Solo/química
8.
Child Neuropsychol ; : 1-32, 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38873994

RESUMO

The Developmental Neuropsychological Assessment - II (NEPSY-II) is a widely used assessment battery in pediatric settings, but its internal structure has not been adequately examined. This study employed a rational, empirical approach to examine the construct validity of 23 NEPSY-II subtest scores from children ages 7-12 (M = 9.99, SD = 2.76) in the NEPSY-II norming sample (N = 600; 50% girls). Competing higher-order models based on prior research, hypothesized NEPSY-II domains, and conceptual subtest classifications were evaluated via confirmatory factor analysis and a sequential approach to model comparisons. The results supported the multidimensionality of NEPSY-II subtests and the organization of subtests by hypothesized neuropsychological domains. The best fitting model included a general factor and four first-order factors. Factor loadings from the general factor to first-order factors were very strong. However, general factor loadings for most subtests were less than .50 (range = .21-.69, M = .44), and domain-specific effects for all subtests, independent of the general factor, were even lower (range = .00-.45, M = .44). Interestingly, all subtests demonstrated strong subtest-specific effects, but it is not clear what construct(s) the subtest-specific effects represent. Findings support NEPSY-II authors' emphasis on subtest-level interpretations rather than composite-level interpretations and highlight that NEPSY-II subtest scores should be interpreted carefully and with caution.

9.
Addict Behav ; 157: 108089, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38908050

RESUMO

BACKGROUND: In November 2019, the Massachusetts legislature passed An Act Modernizing Tobacco Control and became the first state to restrict retail sales of all flavored (including menthol) cigarettes, e-cigarettes, and other tobacco products. Our study aims to provide the retailer experience of the new law from the perspectives of multiple stakeholders, including tobacco retailers themselves, public health officials, and Massachusetts residents. METHODS: We conducted in-depth interviews with seven tobacco retailers and ten public health officials from March 2021 to April 2022. Monthly repeated cross-sectional surveys were administered through the online survey panel Prodege from April 2021 to August 2022 (adult sample: N = 765; adolescent sample: N = 900). Themes from interviews were identified by drawing on deductive codes informed by the interview guide, followed by inductive coding of data. Survey data were descriptively analyzed in R. RESULTS: Key themes included retailer frustration over loss of sales to neighboring states, factors associated with retailer compliance, and the need for increased education regarding the law. Survey results showed that a minority of adolescents (13.3%) and adults (26.1%) who vaped in the past 30-days were traveling to border states to purchase vape products. Less than one-quarter of adolescent participants and less than half of adult participants could correctly identify which products Massachusetts did not sell. CONCLUSIONS: Evidence from the retailer, public health, and end-user perspectives support mutual benefits of adjacent states enacting flavored tobacco sales restrictions, improved policy education for retailers and the public, and improved retailer enforcement.


Assuntos
Comércio , Produtos do Tabaco , Humanos , Massachusetts , Produtos do Tabaco/legislação & jurisprudência , Produtos do Tabaco/economia , Adolescente , Comércio/legislação & jurisprudência , Adulto , Masculino , Feminino , Estudos Transversais , Adulto Jovem , Sistemas Eletrônicos de Liberação de Nicotina , Pessoa de Meia-Idade , Saúde Pública , Controle do Tabagismo
10.
Macromolecules ; 57(11): 5218-5229, 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38882196

RESUMO

Liquid crystal elastomers (LCEs) are polymeric materials that are proposed for a range of applications. However, to reach their full potential, it is desirable to have as much flexibility as possible in terms of the sample dimensions, while maintaining well-defined alignment. In this work, photoinduced electron/energy transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerization is applied to the synthesis of LCEs for the first time. An initial LCE layer (∼100 µm thickness) is partially cured before a second layer of the precursor mixture is added. The curing reaction is then resumed and is observed by FTIR to complete within 15 min of irradiation, yielding samples of increased thickness. Monodomain samples that exhibit an auxetic response and are of thickness 250-300 µm are consistently achieved. All samples are characterized thermally, mechanically, and in terms of their order parameters. The LCEs have physical properties comparable to those of analogous LCEs produced via free-radical polymerization.

11.
Heart Rhythm ; 21(9): 1677-1683, 2024 09.
Artigo em Inglês | MEDLINE | ID: mdl-38797308

RESUMO

BACKGROUND: Percutaneous left atrial appendage closure (LAAC) is an effective alternative strategy for stroke prevention in patients with atrial fibrillation (AF) at high risk for bleeding with anticoagulation (AC). Efficacy of this strategy in hypertrophic cardiomyopathy (HCM) remains uncertain. OBJECTIVE: The study aimed to compare risk of stroke in HCM-AF patients treated with LAAC with those treated with AC. METHODS: By use of the TriNetX Global Research Network, HCM-AF patients from 2015 to 2024 were assigned to categories of treatment with LAAC and treatment solely with AC and observed for 3 years for ischemic stroke, systemic embolism, and all-cause mortality. Propensity score matching was used to limit confounders. RESULTS: Of 14,867 HCM-AF patients identified, 364 (2.5%) were treated with LAAC vs 14,503 (97.5%) treated with AC. HCM LAAC patients were older (72 vs 67 years; P < .001) and had more comorbidities and more prior bleeding events, including higher rate of prior gastrointestinal bleeding (68% vs 18%; P < .001), compared with HCM patients treated solely with AC. After propensity score matching, there was no baseline difference between groups including prior bleeding events (P > .05). During follow-up, HCM patients treated with LAAC had higher rates of ischemic stroke (13% vs 8%; hazard ratio, 1.9; P = .006) and systemic embolism (14% vs 9%; hazard ratio, 1.8; P = .006) but no difference in mortality compared with matched HCM patients receiving AC. CONCLUSION: These real-world data do not support percutaneous LAAC in HCM-AF patients as the primary treatment strategy during long-term AC to reduce stroke risk. However, LAAC may remain a reasonable option for HCM-AF patients who are unable to tolerate AC because of prohibitive bleeding risk.


Assuntos
Apêndice Atrial , Fibrilação Atrial , Cardiomiopatia Hipertrófica , Acidente Vascular Cerebral , Humanos , Fibrilação Atrial/complicações , Fibrilação Atrial/cirurgia , Apêndice Atrial/cirurgia , Masculino , Cardiomiopatia Hipertrófica/complicações , Feminino , Idoso , Acidente Vascular Cerebral/prevenção & controle , Acidente Vascular Cerebral/etiologia , Estudos Retrospectivos , Cateterismo Cardíaco/métodos , Pontuação de Propensão , Resultado do Tratamento , Seguimentos , Anticoagulantes/uso terapêutico , Pessoa de Meia-Idade , Dispositivo para Oclusão Septal , Taxa de Sobrevida/tendências , Oclusão do Apêndice Atrial Esquerdo
12.
Nicotine Tob Res ; 26(Supplement_2): S96-S102, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38817028

RESUMO

INTRODUCTION: The Massachusetts legislature passed An Act Modernizing Tobacco Control in November 2019 to restrict retail sales of flavored commercially manufactured tobacco products including menthol products, increase penalties for violating the law's provisions, and provide health insurance coverage for tobacco treatment. AIMS AND METHODS: This study explores key informants' perceptions of intended and unintended impacts of implementation of the 2019 Massachusetts statewide law through a health equity and racial justice lens. We conducted in-depth interviews with 25 key informants from three key informant groups (public health officials and advocates, clinicians, and school staff) between March 2021 and April 2022. Using deductive codes on unintended impacts of the implementation of the law's policies, we conducted a focused analysis to identify impacts that were perceived and observed by informants from different key informant groups. RESULTS: Perceived or observed impacts of the law were identified across multiple levels by key informants and included concerns related to three broad themes: 1) intended impacts on health equity and racial justice, 2) ongoing availability of restricted products undermining the intended impact of the law, and 3) inequitable targeting by the policies and enforcement among communities of color. CONCLUSIONS: Future evaluation is needed to assess the intended and unintended impacts of implementation of the Massachusetts law to maximize the potential of the policies to reduce tobacco-related health disparities. We discuss implications and recommendations for achieving a national policy and equitable enforcement of flavored tobacco sales restrictions. IMPLICATIONS: This qualitative study among 25 key informants including public health and tobacco control advocates, clinicians, and school staff obtained perspectives of intended and unintended health equity and racial justice impacts of the 2019 Massachusetts An Act Modernizing Tobacco Control. Findings and recommendations from this study can inform monitoring efforts to assess the law's impacts in Massachusetts and the adoption of similar flavored tobacco sales restrictions and other tobacco control policies in other states to maximize the health equity benefits and minimize unintended impacts.


Assuntos
Equidade em Saúde , Produtos do Tabaco , Massachusetts , Humanos , Produtos do Tabaco/legislação & jurisprudência , Justiça Social , Saúde Pública/legislação & jurisprudência , Controle do Tabagismo
13.
JACC Clin Electrophysiol ; 10(7 Pt 1): 1341-1350, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38795100

RESUMO

BACKGROUND: Pulmonary vein isolation (PVI) is increasingly recommended as first-line therapy for atrial fibrillation. Recent data suggest growing PVI volumes but rising complication rates, although comprehensive real-world outcomes including both inpatient and outpatient encounters remain unclear. OBJECTIVES: The purpose of this study was to evaluate patient characteristics, population rates, and 30-day outcomes of PVI in a nationwide sample of U.S. adults aged >65 years. METHODS: First-time PVIs were identified among U.S. Medicare fee-for-service beneficiaries using Current Procedural Terminology procedural codes. Comorbidities were ascertained using International Classification of Diseases-10th Revision diagnosis codes associated with each procedural claim. Outcomes included periprocedural complications, all-cause hospitalizations, and mortality at 30 days. RESULTS: From January 2017 through December 2021, a total of 227,133 patients underwent PVI (mean age 72.5 years, 42% women, 92.7% White) with an increasing comorbidity burden over time. PVI volume increased from 83.8 (2017) to 111.6 per 100,000 patient-years (2021), which was driven by outpatient procedures (87.8% of all PVIs). Concurrently, there was a significant decrease in complication rates (3.9% in 2017 vs 3.1% in 2021; P < 0.001) and hospitalizations (8.8% vs 7.0%; P < 0.001), with no significant change in mortality (0.4%; P = 0.08). The most common periprocedural complications were bleeding (1.8%), pericardial effusion (1.4%), and vascular access damage (0.8%). CONCLUSIONS: The use of PVI has steadily increased among older patients in contemporary U.S. clinical practice; yet, cumulative complication and hospitalization rates at 30 days have decreased over time, with stably low rates of short-term mortality despite rising comorbidity burden among treated patients. These data may reassure patients and providers on the safety of PVI as an increasingly common first-line procedure for atrial fibrillation.


Assuntos
Fibrilação Atrial , Ablação por Cateter , Humanos , Fibrilação Atrial/cirurgia , Fibrilação Atrial/epidemiologia , Idoso , Feminino , Masculino , Estados Unidos/epidemiologia , Ablação por Cateter/estatística & dados numéricos , Ablação por Cateter/efeitos adversos , Idoso de 80 Anos ou mais , Complicações Pós-Operatórias/epidemiologia , Hospitalização/estatística & dados numéricos , Resultado do Tratamento , Medicare/estatística & dados numéricos , Veias Pulmonares/cirurgia , Comorbidade
14.
Pharmaceuticals (Basel) ; 17(4)2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38675371

RESUMO

Brain somatic gene recombination (SGR) and the endogenous reverse transcriptases (RTs) that produce it have been implicated in the etiology of Alzheimer's disease (AD), suggesting RT inhibitors as novel prophylactics or therapeutics. This retrospective, proof-of-concept study evaluated the incidence of AD in people with human immunodeficiency virus (HIV) with or without exposure to nucleoside RT inhibitors (NRTIs) using de-identified medical claims data. Eligible participants were aged ≥60 years, without pre-existing AD diagnoses, and pursued medical services in the United States from October 2015 to September 2016. Cohorts 1 (N = 46,218) and 2 (N = 32,923) had HIV. Cohort 1 had prescription claims for at least one NRTI within the exposure period; Cohort 2 did not. Cohort 3 (N = 150,819) had medical claims for the common cold without evidence of HIV or antiretroviral therapy. The cumulative incidence of new AD cases over the ensuing 2.75-year observation period was lowest in patients with NRTI exposure and highest in controls. Age- and sex-adjusted hazard ratios showed a significantly decreased risk for AD in Cohort 1 compared with Cohorts 2 (HR 0.88, p < 0.05) and 3 (HR 0.84, p < 0.05). Sub-grouping identified a decreased AD risk in patients with NRTI exposure but without protease inhibitor (PI) exposure. Prospective clinical trials and the development of next-generation agents targeting brain RTs are warranted.

15.
ACS Nano ; 18(17): 11245-11256, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38639708

RESUMO

Active metasurfaces with tunable subwavelength-scale nanoscatterers are promising platforms for high-performance spatial light modulators (SLMs). Among the tuning methods, phase-change materials (PCMs) are attractive because of their nonvolatile, threshold-driven, and drastic optical modulation, rendering zero-static power, crosstalk immunity, and compact pixels. However, current electrically controlled PCM-based metasurfaces are limited to global amplitude modulation, which is insufficient for SLMs. Here, an individual-pixel addressable, transmissive metasurface is experimentally demonstrated using the low-loss PCM Sb2Se3 and doped silicon nanowire heaters. The nanowires simultaneously form a diatomic metasurface, supporting a high-quality-factor (∼406) quasi-bound-state-in-the-continuum mode. A global phase-only modulation of ∼0.25π (∼0.2π) in simulation (experiment) is achieved, showing ten times enhancement. A 2π phase shift is further obtained using a guided-mode resonance with enhanced light-Sb2Se3 interaction. Finally, individual-pixel addressability and SLM functionality are demonstrated through deterministic multilevel switching (ten levels) and tunable far-field beam shaping. Our work presents zero-static power transmissive phase-only SLMs, enabled by electrically controlled low-loss PCMs and individual meta-molecule addressable metasurfaces.

16.
Phys Rev Lett ; 132(11): 110601, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38563919

RESUMO

Simulators can realize novel phenomena by separating them from the complexities of a full physical implementation. Here, we put forward a scheme that can simulate the exotic statistics of D(S_{3}) non-Abelian anyons with minimal resources. The qudit lattice representation of this planar code supports local encoding of D(S_{3}) anyons. As a proof-of-principle demonstration, we employ a classical photonic simulator to encode a single qutrit and manipulate it to perform the fusion and braiding properties of non-Abelian D(S_{3}) anyons. The photonic technology allows us to perform the required nonunitary operations with much higher fidelity than what can be achieved with current quantum computers. Our approach can be directly generalized to larger systems or to different anyonic models, thus enabling advances in the exploration of quantum error correction and fundamental physics alike.

17.
J Anim Sci ; 1022024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38442241

RESUMO

This study evaluated the effect of feeding ergot contaminated grain continuously or intermittently through backgrounding (BG) and finishing (FN) in a mash or pelleted supplement on the growth performance, health and welfare parameters, and carcass characteristics of feedlot beef steers. Sixty black Angus steers (300 ±â€…29.4 kg BW) were used in a complete randomized 238-d study. Steers were stratified by weight and randomly assigned to four different diets (15 steers/treatment) and individually housed. Treatments included: (1) control [CON; no added ergot alkaloids (EA)], (2) continuous ergot mash (CEM; fed continuously at 2 mg total EA/kg of DM), (3) intermittent ergot mash (IEM; fed at 2 mg total EA/kg of DM, during the first week of each 21-d period and CON for the remaining 2 wk, this feeding pattern was repeated in each period), and (4) intermittent ergot pellet (IEP; fed at 2 mg of total EA/kg of DM as a pellet during the first week of each 21-d period and CON for the remaining 2 wk as described for IEM). Steers were fed barley based BG diets containing 40% concentrate:60% silage (DM basis) for 84 d (four 21-d periods), transitioned over 28 d (no ergot fed) to an FN diet (90% concentrate:10% silage DM basis) and fed for 126 d (six 21-d periods) before slaughter. In the BG phase, steer DMI (P < 0.01, 7.45 vs. 8.05 kg/d) and ADG (P < 0.01) were reduced for all EA diets compared to CON. The CEM fed steers had lower ADG (P < 0.01, 0.735 vs. 0.980 kg) and shrunk final BW (P < 0.01, 350 vs. 366 kg) than CON. CEM had lower gain:feed (P < 0.07, 0.130 vs. 0.142) than CON. In the FN phase, steer DMI (P < 0.01, 9.95 vs. 11.05 kg/d) and ADG (P = 0.04) were also decreased for all EA fed steers compared to CON. Total shrunk BW gain (P = 0.03, 202.5 vs. 225.2 kg), final BW (P = 0.03, 617.9 vs. 662.2 kg), and carcass weight (P = 0.06) decreased for all EA fed steers compared to CON. The percentage of AAA carcasses decreased for all EA fed steers (P < 0.01, 46.7 vs. 93.3%) compared to CON. EA fed steers had increased rectal temperatures (P < 0.01, 39.8 vs. 39.4 °C) compared to CON. Pelleting ergot contaminated grain did not reduce the impact of ergot alkaloids on any of the measured parameters during BG or FN. Continuously or intermittently feeding ergot contaminated diets (2 mg total EA/kg of DM) significantly reduced intake, growth performance, and carcass weight, with minimal impact on blood parameters in feedlot steers. Pelleting was not an effective method of reducing ergot toxicity.


Produced by the fungus Claviceps purpurea, ergot alkaloids (EA) are toxic to beef cattle when consumed and can lead to reduction in feed intake and growth performance, vasoconstriction of the blood vessels, hyperthermia, damage to extremities (ears, tails, and hooves) and in severe cases, death. Grain is often cleaned to meet quality standards, and the resulting screenings are often utilized for feeding livestock and can have high concentrations of EA. The application of heat during pelleting of EA contaminated grain has been suggested to reduce its toxicity. Backgrounding and finishing beef cattle feeding experiments were conducted to assess the effect of continuously or intermittently feeding EA contaminated grain (2 mg/kg of diet DM) either as a pellet or as mash on growth performance, health, and animal welfare. Feeding EA grain continuously or intermittently either as a mash or pellet drastically reduced growth performance of steers, with no difference between treatments.


Assuntos
Ração Animal , Alcaloides de Claviceps , Bovinos , Animais , Ração Animal/análise , Dieta/veterinária , Suplementos Nutricionais , Silagem/análise , Grão Comestível
18.
Crop Sci ; 64(1): 314-332, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38516200

RESUMO

Radiation-use efficiency (RUE) is an important trait for raising biomass and yield potential in plant breeding. However, the effect of the planting system (PS) on genetic variation in RUE has not been previously investigated. Our objectives were to quantify genetic variation in RUE, biomass and grain yield in raised-bed and flat-basin planting systems, and associations with canopy-architecture traits (flag-leaf angle and curvature). Twelve spring wheat (Triticum aestivum L.) cultivars were evaluated under irrigated conditions for 3 years in North West Mexico using raised-bed and flat-basin planting systems. Canopy architecture traits were measured at booting and anthesis + 7 days. Grain yield (10.6%), biomass (7.6%), and pre-grain-filling RUE (9.7%) were higher in raised beds than flat basins, while a significant planting system × genotype interaction was found for grain yield. Genetic variation in pre-grain-filling RUE was associated with biomass and grain yield in beds and basins. In flat basins, higher pre-grain-filling RUE was correlated with a more upright flag-leaf angle but not in raised beds. In raised beds, cultivars with less upright flag-leaf angle had greater fractional light interception pre-anthesis. Taller semi-dwarf cultivars intercepted relatively more radiation in the beds than the flats before anthesis, consistent with the taller cultivars showing relatively greater increases in yield in beds compared to flats. Our results indicated that the evaluation of genotypes for RUE and biomass in wheat breeding should take into account planting systems to capture genotype × PS effects. In addition, the results demonstrate how flag-leaf angle has a different effect depending on the planting system.

19.
Macromolecules ; 57(5): 2030-2038, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38495386

RESUMO

Determining the tunability of the optical coefficients, order parameter, and transition temperatures in optically transparent auxetic liquid crystal elastomers (LCEs) is vital for applications, including impact-resistant glass laminates. Here, we report measurements of the refractive indices, order parameters, and transition temperatures in a family of acrylate-based LCEs in which the mesogenic content varies from ∼50 to ∼85%. Modifications in the precursor mixture allow the order parameter, ⟨P2⟩, of the LCE to be adjusted from 0.46 to 0.73. The extraordinary refractive index changes most significantly with composition, from ∼1.66 to ∼1.69, in moving from a low to high mesogenic content. We demonstrate that all LCE refractive indices decrease with increasing temperature, with temperature coefficients of ∼10-4 K-1, comparable to optical plastics. In these LCEs, the average refractive index and the refractive index anisotropy are tunable via both chemical composition and order parameter control; we report design rules for both.

20.
Healthcare (Basel) ; 12(5)2024 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-38470650

RESUMO

OBJECTIVES: Social isolation is recognised as a risk factor in the inflammatory process. This study explored the association between social isolation and the Dietary Inflammatory Index (DII) in community-dwelling older persons. METHODS: This cross-sectional pilot study recruited 107 community-dwelling people aged over 55 years living in the Australian Capital Territory. Participants completed an extensive food frequency questionnaire and provided anthropometric and sociodemographic data. Social isolation was evaluated using the Lubben Social Network Scale (LSNS). Diet quality was assessed using DII. RESULTS: Average age was 70.1 (±8.61) years and 62.8% were female. The average DII score was -1.10 (±1.21), indicating an anti-inflammatory diet. Higher LSNS was associated with lower DII (b (95% CI) = -0.041 (-0.066, -0.17); p < 0.01) and was positively influenced by the number of people in household (b (95% CI) = 5.731 (2.336, 9.127); p = 0.001). CONCLUSION: Increased risk of social isolation was associated with an increased tendency towards a more inflammatory diet. Reducing social isolation may decrease the inflammatory component of dietary intake for older persons living independently in the community.

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