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3.
J Phys Condens Matter ; 35(29)2023 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-37044099

RESUMO

Single crystals ofLnRu2Ga8andLnCo2Al8(Ln= La and Pr) were grown using a Ga/Al self-flux method. An orthorhombic CaCo2Al8-type structure with space groupPbam(No.55) of them was identified by x-ray diffraction. LaRu2Ga8and LaCo2Al8are Pauli paramagnetic down to 2 K, while PrRu2Ga8and PrCo2Al8show antiferromagnetic (AFM) order at 2.5 and 5 K, respectively. Strong magnetic anisotropy in PrRu2Ga8and PrCo2Al8single crystals was found by an anisotropic magnetic measurement. The field-induced FM state was observed in both PrRu2Ga8and PrCo2Al8forH||c. However, in the case of H⊥c, the AFM state is robust. The strong magnetic anisotropy in PrRu2Ga8FM and PrCo2Al8is due to their anisotropic magnetic interactions that FM interactions are dominant in the case ofH||cwhile AFM interactions forH⊥c.

5.
Curr Zool ; 68(3): 285-293, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35592347

RESUMO

China is a country with one of the most species-rich reptile faunas in the world. However, nearly a quarter of Chinese lizard species assessed by the China Biodiversity Red List are threatened. Nevertheless, to date, no study has explicitly examined the pattern and processes of extinction and threat in Chinese lizards. In this study, we conducted the first comparative phylogenetic analysis of extinction risk in Chinese lizards. We addressed the following 3 questions: (1) What is the pattern of extinction and threat in Chinese lizards? (2) Which species traits and extrinsic factors are related to their extinction risk? (3) How can we protect Chinese lizards based on our results? We collected data on 10 species traits (body size [BS], clutch size, geographic range size, activity time, reproductive mode, habitat specialization [HS], habitat use, leg development, maximum elevation, and elevation range) and 7 extrinsic factors (mean annual precipitation (MAP), mean annual temperature, mean annual solar insolation, normalized difference vegetation index (NDVI), human footprint, human population density, and human exploitation). After phylogenetic correction, these variables were used separately and in combination to assess their associations with extinction risk. We found that Chinese lizards with a small geographic range, large BS, high HS, and living in high MAP areas were vulnerable to extinction. Conservation priority should thus be given to species with the above extinction-prone traits so as to effectively protect Chinese lizards. Preventing future habitat destruction should also be a primary focus of management efforts because species with small range size and high HS are particularly vulnerable to habitat loss.

7.
Arterioscler Thromb Vasc Biol ; 41(4): 1428-1445, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33626912
8.
Cell Host Microbe ; 28(6): 825-837.e6, 2020 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-33027611

RESUMO

Plants benefit from associations with a diverse community of root-colonizing microbes. Deciphering the mechanisms underpinning these beneficial services are of interest for improving plant productivity. We report a plant-beneficial interaction between Arabidopsis thaliana and the root microbiota under iron deprivation that is dependent on the secretion of plant-derived coumarins. Disrupting this pathway alters the microbiota and impairs plant growth in iron-limiting soil. Furthermore, the microbiota improves iron-limiting plant performance via a mechanism dependent on plant iron import and secretion of the coumarin fraxetin. This beneficial trait is strain specific yet functionally redundant across phylogenetic lineages of the microbiota. Transcriptomic and elemental analyses revealed that this interaction between commensals and coumarins promotes growth by relieving iron starvation. These results show that coumarins improve plant performance by eliciting microbe-assisted iron nutrition. We propose that the bacterial root microbiota, stimulated by secreted coumarins, is an integral mediator of plant adaptation to iron-limiting soils.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/microbiologia , Arabidopsis/fisiologia , Cumarínicos/metabolismo , Ferro/metabolismo , Raízes de Plantas/microbiologia , Raízes de Plantas/fisiologia , Perfilação da Expressão Gênica , Microbiota , Filogenia , Rizosfera , Metabolismo Secundário , Solo/química , Microbiologia do Solo , Simbiose
9.
Proc Natl Acad Sci U S A ; 116(25): 12558-12565, 2019 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-31152139

RESUMO

The factors that contribute to the composition of the root microbiome and, in turn, affect plant fitness are not well understood. Recent work has highlighted a major contribution of the soil inoculum in determining the composition of the root microbiome. However, plants are known to conditionally exude a diverse array of unique secondary metabolites, that vary among species and environmental conditions and can interact with the surrounding biota. Here, we explore the role of specialized metabolites in dictating which bacteria reside in the rhizosphere. We employed a reduced synthetic community (SynCom) of Arabidopsis thaliana root-isolated bacteria to detect community shifts that occur in the absence of the secreted small-molecule phytoalexins, flavonoids, and coumarins. We find that lack of coumarin biosynthesis in f6'h1 mutant plant lines causes a shift in the root microbial community specifically under iron deficiency. We demonstrate a potential role for iron-mobilizing coumarins in sculpting the A. thaliana root bacterial community by inhibiting the proliferation of a relatively abundant Pseudomonas species via a redox-mediated mechanism. This work establishes a systematic approach enabling elucidation of specific mechanisms by which plant-derived molecules mediate microbial community composition. Our findings expand on the function of conditionally exuded specialized metabolites and suggest avenues to effectively engineer the rhizosphere with the aim of improving crop growth in iron-limited alkaline soils, which make up a third of the world's arable soils.


Assuntos
Arabidopsis/microbiologia , Cumarínicos/metabolismo , Microbiota , Raízes de Plantas/microbiologia , Arabidopsis/metabolismo , Arabidopsis/fisiologia , Fotossíntese , Raízes de Plantas/metabolismo , Pseudomonas/metabolismo , Rizosfera
10.
J Lipid Res ; 59(9): 1783-1790, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30026263

RESUMO

Fat-soluble vitamins (FSVs), A, D, and E, are components of prenatal vitamin care. Previously, limited evidence existed to explain on a molecular level how maternal FSV supplementation affects the fetus during pregnancy. We developed a simplified LC-MS/MS method to simultaneously detect FSVs in maternal plasma (MP) and amniotic fluid (AF); we used this approach to investigate the correlation between FSV levels in these two matrices. With this method, we circumvented frequently used liquid-liquid extraction or solid-phase extraction methods and, instead, used simple protein precipitation with acetonitrile for sample preparation. This method displayed satisfactory linearity, intra- and inter-day imprecision, and accuracy. We validated the consistency with standard reference material 972a and 968f certification. In analysis of MP and AF samples from 50 pregnant women in the second trimester, concentrations of retinol, 25-hydroxyvitamin D3 [25(OH)D3], and α-tocopherol (reflecting vitamins A, D, and E, respectively) were lower in AF than in MP. Significant positive correlations existed between MP and AF for 25(OH)D3 (r = 0.667; P < 0.001) and retinol (r = 0.393; P = 0.005), but not for α-tocopherol (r = 0.145, P > 0.05). This novel LC-MS/MS method shows prominent applicability for FSV detection and the observed correlations contribute to research on fetal development.


Assuntos
Líquido Amniótico/química , Cromatografia Líquida/métodos , Espectrometria de Massas em Tandem/métodos , Vitaminas/análise , Vitaminas/química , Adulto , Ácidos Graxos/química , Feminino , Humanos , Masculino , Solubilidade , Vitaminas/sangue , Adulto Jovem
12.
Hernia ; 21(3): 369-376, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-27215430

RESUMO

PURPOSE: Lumbar hernias are protrusions of intra-abdominal contents classically through the superior (Grynfeltt) and inferior (Petit) lumbar triangles. The anatomy of the triangles is variable and quantitative data are few. No radiological data on the anatomy of the triangles are available. METHODS: Fifty computed tomography angiography of the upper abdomen (M25, F25, mean age 72.5-year-old) were analyzed. The dimensions and the contents of the lumbar triangles were analyzed. The characteristics of the space between the two triangles were also documented. RESULTS: The superior lumbar triangle showed a mean surface area of 5.10 ± 2.6 cm2. In the area of the triangle, the 12th intercostal pedicle and the 1st lumbar branches of the iliolumbar vessels were found in 42 and 46 %, respectively. The inferior lumbar triangle had a mean surface of area 18.7 ± 8.4 cm2. In this area, the 2nd, 3rd, and 4th lumbar branches were found in 9, 67, and 8 %, respectively. On oblique coronal images, a direct tunnel between the superior and the inferior lumbar triangles was found, showing an oblique course, with a postero-anterior direction (mean length 36.5 ± 5.8 mm, mean caliber 7.4 ± 3.1 mm). CONCLUSIONS: Among the anatomical factors of weakening of the abdominal wall, the course of branches of the lumbar vessels was documented not only in the superior but also in the inferior lumbar triangle. A real musculoaponeurotic tunnel between the superior and the inferior lumbar triangles located in the oblique coronal plane was found, that could play a role in the development of incarceration or strangulation of lumbar hernias.


Assuntos
Parede Abdominal/diagnóstico por imagem , Hérnia Abdominal/diagnóstico por imagem , Região Lombossacral/diagnóstico por imagem , Parede Abdominal/anatomia & histologia , Parede Abdominal/irrigação sanguínea , Idoso , Angiografia por Tomografia Computadorizada , Feminino , Hérnia Abdominal/cirurgia , Humanos , Região Lombossacral/anatomia & histologia , Região Lombossacral/irrigação sanguínea , Região Lombossacral/cirurgia , Masculino
13.
Med Phys ; 42(2): 623-36, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25652480

RESUMO

PURPOSE: The authors are developing a system for calibrated breast density measurements using full field digital mammography (FFDM). Breast tissue equivalent (BTE) phantom images are used to establish baseline (BL) calibration curves at time zero. For a given FFDM unit, the full BL dataset is comprised of approximately 160 phantom images, acquired prior to calibrating prospective patient mammograms. BL curves are monitored serially to ensure they produce accurate calibration and require updating when calibration accuracy degrades beyond an acceptable tolerance, rather than acquiring full BL datasets repeatedly. BL updating is a special case of generalizing calibration datasets across FFDM units, referred to as cross-calibration. Serial monitoring, BL updating, and cross-calibration techniques were developed and evaluated. METHODS: BL curves were established for three Hologic Selenia FFDM units at time zero. In addition, one set of serial phantom images, comprised of equal proportions of adipose and fibroglandular BTE materials (50/50 compositions) of a fixed height, was acquired biweekly and monitored with the cumulative sum (Cusum) technique. These 50/50 composition images were used to update the BL curves when the calibration accuracy degraded beyond a preset tolerance of ±4 standardized units. A second set of serial images, comprised of a wide-range of BTE compositions, was acquired biweekly to evaluate serial monitoring, BL updating, and cross-calibration techniques. RESULTS: Calibration accuracy can degrade serially and is a function of acquisition technique and phantom height. The authors demonstrated that all heights could be monitored simultaneously while acquiring images of a 50/50 phantom with a fixed height for each acquisition technique biweekly, translating into approximately 16 image acquisitions biweekly per FFDM unit. The same serial images are sufficient for serial monitoring, BL updating, and cross-calibration. Serial calibration accuracy was maintained within ±4 standardized unit variation from the ideal when applying BL updating. BL updating is a special case of cross-calibration; the BL dataset of unit 1 can be converted to the BL dataset for another similar unit (i.e., unit 2) at any given time point using the 16 serial monitoring 50/50 phantom images of unit 2 (or vice versa) acquired near this time point while maintaining the ±4 standardized unit tolerance. CONCLUSIONS: A methodology for monitoring and maintaining serial calibration accuracy for breast density measurements was evaluated. Calibration datasets for a given unit can be translated forward in time with minimal phantom imaging effort. Similarly, cross-calibration is a method for generalizing calibration datasets across similar units without additional phantom imaging. This methodology will require further evaluation with mammograms for complete validation.


Assuntos
Mama/citologia , Mamografia/métodos , Intensificação de Imagem Radiográfica/métodos , Calibragem , Humanos , Imagens de Fantasmas , Controle de Qualidade
15.
Eur J Vasc Endovasc Surg ; 24(4): 322-31, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12323175

RESUMO

BACKGROUND AND OBJECTIVE: intimal hyperplasia (IH) and constrictive remodelling are important causes of restenosis following endovascular interventions, such as percutaneous transluminal angioplasty. Photodynamic therapy (PDT) with 5-aminolaevulinic (ALA) may prevent restenosis by cellular depletion and the elimination of cholinergic innervation. STUDY DESIGN/MATERIALS AND METHODS: rats (n=90) were subdivided into 4 main groups. In the experimental group (n=36: 3 replications x 4 doses x 3 examination time-points), ALA was administered (200mg/kg i.v.) 2-3h before balloon injury (BI) of the common iliac artery followed by endovascular illumination with 633nm at either 12.5, 25, 50 or 100J/cm diffuser length (dl BI+PDT group). As control groups served the BI+Light only (LO) group (n=36) that received no ALA, the BI only group (n=9) (BI), and a group (n=9) that received a Sham procedure (Sham group). RESULTS: planimetric analysis showed IH of 0.28+/-0.12mm(2) (BI), 0.27+/-0.12mm(2) (BI+LO at 100J/cmdl) in contrast to 0.02+/-0.02mm(2) after BI+PDT at 100J/cmdl at 16 weeks (p<0.05). In the BI+PDT groups, a light-dose increase of a factor 2 led to an IH decrease of 17% (p<0.05). In the BI and BI+LO groups constrictive remodelling was found, in contrast to BI+PDT treated groups at 16 weeks. The staining of cholinergic innervation of the tunic media of the blood vessel wall in BI+PDT showed no damage at the highest fluence. CONCLUSION: endovascular ALA-PDT prevents IH and constrictive remodelling after BI without damage of cholinergic innervation of the tunica media. The effective light fluence rate in the rat is 50-100J/cmdl.


Assuntos
Ácido Aminolevulínico/administração & dosagem , Ácido Aminolevulínico/uso terapêutico , Angioplastia com Balão/efeitos adversos , Hiperplasia/etiologia , Hiperplasia/prevenção & controle , Fotoquimioterapia , Fármacos Fotossensibilizantes/administração & dosagem , Fármacos Fotossensibilizantes/uso terapêutico , Túnica Íntima/efeitos dos fármacos , Túnica Íntima/cirurgia , Animais , Constrição Patológica/etiologia , Constrição Patológica/patologia , Constrição Patológica/prevenção & controle , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Hiperplasia/patologia , Masculino , Distribuição Aleatória , Ratos , Ratos Wistar , Fatores de Tempo , Túnica Íntima/patologia
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