Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 126
Filtrar
1.
Proc Natl Acad Sci U S A ; 119(4)2022 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-35064084

RESUMO

Substantial improvements in cycle life, rate performance, accessible voltage, and reversible capacity are required to realize the promise of Li-ion batteries in full measure. Here, we have examined insertion electrodes of the same composition (V2O5) prepared according to the same electrode specifications and comprising particles with similar dimensions and geometries that differ only in terms of their atomic connectivity and crystal structure, specifically two-dimensional (2D) layered α-V2O5 that crystallizes in an orthorhombic space group and one-dimensional (1D) tunnel-structured ζ-V2O5 crystallized in a monoclinic space group. By using particles of similar dimensions, we have disentangled the role of specific structural motifs and atomistic diffusion pathways in affecting electrochemical performance by mapping the dynamical evolution of lithiation-induced structural modifications using ex situ scanning transmission X-ray microscopy, operando synchrotron X-ray diffraction measurements, and phase-field modeling. We find the operation of sharply divergent mechanisms to accommodate increasing concentrations of Li-ions: a series of distortive phase transformations that result in puckering and expansion of interlayer spacing in layered α-V2O5, as compared with cation reordering along interstitial sites in tunnel-structured ζ-V2O5 By alleviating distortive phase transformations, the ζ-V2O5 cathode shows reduced voltage hysteresis, increased Li-ion diffusivity, alleviation of stress gradients, and improved capacity retention. The findings demonstrate that alternative lithiation mechanisms can be accessed in metastable compounds by dint of their reconfigured atomic connectivity and can unlock substantially improved electrochemical performance not accessible in the thermodynamically stable phase.

2.
J Chem Phys ; 160(19)2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38747548

RESUMO

The efficient conversion of solar energy to chemical energy represents a critical bottleneck to the energy transition. Photocatalytic splitting of water to generate solar fuels is a promising solution. Semiconductor quantum dots (QDs) are prime candidates for light-harvesting components of photocatalytic heterostructures, given their size-dependent photophysical properties and band-edge energies. A promising series of heterostructured photocatalysts interface QDs with transition-metal oxides which embed midgap electronic states derived from the stereochemically active electron lone pairs of p-block cations. Here, we examine the thermodynamic driving forces and dynamics of charge separation in Sb2VO5/CdSe QD heterostructures, wherein a high density of Sb 5s2-derived midgap states are prospective acceptors for photogenerated holes. Hard-x-ray valence band photoemission spectroscopy measurements of Sb2VO5/CdSe QD heterostructures were used to deduce thermodynamic driving forces for charge separation. Interfacial charge transfer dynamics in the heterostructures were examined as a function of the mode of interfacial connectivity, contrasting heterostructures with direct interfaces assembled by successive ion layer adsorption and reaction (SILAR) and interfaces comprising molecular bridges assembled by linker-assisted assembly (LAA). Transient absorption spectroscopy measurements indicate ultrafast (<2 ps) electron and hole transfer in SILAR-derived heterostructures, whereas LAA-derived heterostructures show orders of magnitude differentials in the kinetics of hole (<100 ps) and electron (∼1 ns) transfer. The interface-modulated kinetic differentials in electron and hole transfer rates underpin the more effective charge separation, reduced charge recombination, and greater photocatalytic efficiency observed for the LAA-derived Sb2VO5/CdSe QD heterostructures.

3.
Clin Anat ; 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38984460

RESUMO

The diameter (mPAD) of the main pulmonary artery (pulmonary artery trunk) is a crucial indicator for cardiovascular health and prognoses in various conditions. Its enlargement is associated with increased mortality and severity in COVID-19-related pneumonia. However, its relevance to non-COVID pneumonia remains uncertain. The aim of this study was to establish an association between mPAD and the severity of non-COVID pneumonia. Eligible participants with qualified Chest Computed Tomography scans from November 2019 to February 2023 were recruited to a cross-sectional retrospective study. They were stratified into pneumonia and non-pneumonia cohorts. Exclusion criteria included pulmonary hypertension, polytrauma, lung neoplasia, or a history of pulmonary stenosis repair. The mPAD was measured in both groups, and medical records were reviewed to identify comorbidities. Pulmonary CT data were classified by pattern and severity, and the mPAD was measured perpendicularly to the long axis of the artery at the point of bifurcation on an axial slice. Analysis of 380 CT scans (52.6% men, 47.4% women; mean age 52.88 ± 17.58) revealed a significant difference in mPAD between pneumonia and non-pneumonia cases (mean difference: 1.19 mm, 95% CI [0.46, 1.92], p = 0.001). Age correlated positively with mPAD (r = 0.231, 95% CI [0.028, 0.069], p < 0.0001), and this correlation persisted after adjusting for confounders (r = 0.220, 95% CI [0.019, 0.073], p = 0.001). Ordinal logistic regression indicated 1.28 times higher odds of severe pneumonia with a larger diameter. The study highlights associations between mPAD, pneumonia, and severity, suggesting clinical relevance. Furthermore, the mPAD should be carefully considered in defining severity criteria for adverse outcomes in pneumonia patients. Further research is needed to refine clinical criteria on the basis of these findings.

4.
Nat Mater ; 21(2): 217-227, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34824396

RESUMO

Lithium-ion batteries are yet to realize their full promise because of challenges in the design and construction of electrode architectures that allow for their entire interior volumes to be reversibly accessible for ion storage. Electrodes constructed from the same material and with the same specifications, which differ only in terms of dimensions and geometries of the constituent particles, can show surprising differences in polarization, stress accumulation and capacity fade. Here, using operando synchrotron X-ray diffraction and energy dispersive X-ray diffraction (EDXRD), we probe the mechanistic origins of the remarkable particle geometry-dependent modification of lithiation-induced phase transformations in V2O5 as a model phase-transforming cathode. A pronounced modulation of phase coexistence regimes is observed as a function of particle geometry. Specifically, a metastable phase is stabilized for nanometre-sized spherical V2O5 particles, to circumvent the formation of large misfit strains. Spatially resolved EDXRD measurements demonstrate that particle geometries strongly modify the tortuosity of the porous cathode architecture. Greater ion-transport limitations in electrode architectures comprising micrometre-sized platelets result in considerable lithiation heterogeneities across the thickness of the electrode. These insights establish particle geometry-dependent modification of metastable phase regimes and electrode tortuosity as key design principles for realizing the promise of intercalation cathodes.

5.
Monaldi Arch Chest Dis ; 93(1)2022 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-35678532

RESUMO

Combined treatments against SARS-CoV-2 are emerging and some have taken into account the post-COVID-19 fibrosis. The aim of this survey was to report the experience of treating COVID-19 patients with pirfenidone, nitazoxanide (NTZ) and colchicine. It was a case series report of COVID-19 patients treated from December 2020 to March 2021, in a rural health center located in the State of Mexico, Mexico. 23 patients were included (mean age 44.5 ± 17.1 years), 12 women (mean age 45.9 ± 17.9 years) and 11 men (mean age 43 ± 16.9 years) with four deaths (17.39%). The evolution time was of 17.3 ± 6.7 days being the main symptoms fever (82.6%), myalgia (69.6%) and cough (65.2%). The main comorbidities were overweight/obesity 18 (78.26%), type 2 diabetes mellitus (T2DM) 4 (17.39%), Chronic obstructive pulmonary disease (COPD) 5 (21.73%) and systemic hypertension 2 (8.69%). Two patients were intubated and both died; in these cases, they refused to take NTZ until after three days the medical doctor had prescribed it for the first time. It can be concluded that implementing a mixed treatment with pirfenidone, NTZ and colchicine could improve the survival rate in ambulatory patients of low socioeconomic status.


Assuntos
COVID-19 , Diabetes Mellitus Tipo 2 , Masculino , Humanos , Feminino , Adulto , Pessoa de Meia-Idade , SARS-CoV-2 , Colchicina/uso terapêutico
7.
Blood ; 143(4): 375, 2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38270939
8.
Opt Express ; 29(24): 39709-39717, 2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34809328

RESUMO

For extending focal depth we employ a set of transparent concentric rings, which are coded with the Barker sequences of length L. At the neighborhood of the paraxial focal plane, these transparent masks generate an axial uniform distribution, which is modulated with sinusoidal variations. For imaging applications, one can extend focal depth if the Barker length is congruent to unity modulo 4. And, for optical trapping, a bottle neck irradiance distribution is generated if the Barker length is congruent to three modulo 4.

10.
Molecules ; 26(1)2021 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-33466389

RESUMO

This research work reports the potential of maleinized linseed oil (MLO) as biobased compatibilizer in polylactide (PLA) and a thermoplastic elastomer, namely, polystyrene-b-(ethylene-ran-butylene)-b-styrene (SEBS) blends (PLA/SEBS), with improved impact strength for the packaging industry. The effects of MLO are compared with a conventional polystyrene-b-poly(ethylene-ran-butylene)-b-polystyrene-graft-maleic anhydride terpolymer (SEBS-g-MA) since it is widely used in these blends. Uncompatibilized and compatibilized PLA/SEBS blends can be manufactured by extrusion and then shaped into standard samples for further characterization by mechanical, thermal, morphological, dynamical-mechanical, wetting and colour standard tests. The obtained results indicate that the uncompatibilized PLA/SEBS blend containing 20 wt.% SEBS gives improved toughness (4.8 kJ/m2) compared to neat PLA (1.3 kJ/m2). Nevertheless, the same blend compatibilized with MLO leads to an increase in impact strength up to 6.1 kJ/m2, thus giving evidence of the potential of MLO to compete with other petroleum-derived compatibilizers to obtain tough PLA formulations. MLO also provides increased ductile properties, since neat PLA is a brittle polymer with an elongation at break of 7.4%, while its blend with 20 wt.% SEBS and MLO as compatibilizer offers an elongation at break of 50.2%, much higher than that provided by typical SEBS-g-MA compatibilizer (10.1%). MLO provides a slight decrease (about 3 °C lower) in the glass transition temperature (Tg) of the PLA-rich phase, thus showing some plasticization effects. Although MLO addition leads to some yellowing due to its intrinsic yellow colour, this can contribute to serving as a UV light barrier with interesting applications in the packaging industry. Therefore, MLO represents a cost-effective and sustainable solution to the use of conventional petroleum-derived compatibilizers.


Assuntos
Materiais Biocompatíveis/química , Elastômeros/química , Óleo de Semente do Linho/química , Anidridos Maleicos/química , Poliésteres/química , Polímeros/química , Embalagem de Produtos/métodos , Temperatura , Resistência à Tração
12.
Appl Opt ; 59(22): 6632-6637, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32749365

RESUMO

For optically narrowing field depth, we explore the use of annular masks that are coded with the elements of Hadamard matrices. We show that with no further reduction of light throughput, these annular masks can enhance the influence of focus error on the modulation transfer functions (MTF). We report numerical evaluations of the irradiance point spread functions (PSFs), their associated MTFs, and of some digitally generated images. For complementing our assessments, we evaluate the Fisher information of these Walsh-Hadamard, annular masks. We suggest an optical technique for breaking 3-D scenes into several 2-D sliced frames by translating out-of-focus images into background noise.

13.
Molecules ; 25(8)2020 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-32340300

RESUMO

In this work, films of polylactide (PLA) prepared by extrusion and thermo-compression were plasticized with oligomer of lactic acid (OLA) at contents of 5, 10, and 20 wt%. The PLA sample containing 20 wt% of OLA was also reinforced with 3, 6, and 9 parts per hundred resin (phr) of halloysite nanotubes (HNTs) to increase the mechanical strength and thermal stability of the films. Prior to melt mixing, ultrasound-assisted dispersion of the nanoclays in OLA was carried out at 100 °C to promote the HNTs dispersion in PLA and the resultant films were characterized with the aim to ascertain their potential in food packaging. It was observed that either the individual addition of OLA or combined with 3 phr of HNTs did not significantly affect the optical properties of the PLA films, whereas higher nanoclay contents reduced lightness and induced certain green and blue tonalities. The addition of 20 wt% of OLA increased ductility of the PLA film by nearly 75% and also decreased the glass transition temperature (Tg) by over 18 °C. The incorporation of 3 phr of HNTs into the OLA-containing PLA films delayed thermal degradation by 7 °C and additionally reduced the permeabilities to water and limonene vapors by approximately 8% and 47%, respectively. Interestingly, the highest barrier performance was attained for the unfilled PLA film plasticized with 10 wt% of OLA, which was attributed to a crystallinity increase and an effect of "antiplasticization". However, loadings of 6 and 9 phr of HNTs resulted in the formation of small aggregates that impaired the performance of the blend films. The here-attained results demonstrates that the properties of ternary systems of PLA/OLA/HNTs can be tuned when the plasticizer and nanofiller contents are carefully chosen and the resultant nanocomposite films can be proposed as a bio-sourced alternative for compostable packaging applications.


Assuntos
Filmes Comestíveis , Embalagem de Alimentos , Nanotubos/química , Poliésteres/química , Nanocompostos/química , Análise Espectral , Resistência à Tração , Termodinâmica , Ondas Ultrassônicas
14.
Transpl Infect Dis ; 21(5): e13139, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31271696

RESUMO

PURPOSE: Solid organ transplant recipients are highly susceptible to Toxoplasma gondii infection. We aimed to describe the 12-month follow-up risk of seroconversion in renal transplant recipients. METHODOLOGY: Anti-T gondii antibodies were investigated in donors and recipients of renal transplants. In donors, anti-T gondii were evaluated before transplantation. In recipients, anti-T gondii were monitored over a 12-month period to evaluate potential seroconversion or reactivation. IgG and IgM anti-T gondii antibodies were investigated through enzyme immunoassay and Western blot. Molecular diagnosis was performed on peripheral blood leukocytes using PCR to amplify fragments corresponding to the T gondii B1 gene and the repetitive 529-bp element. RESULTS: The basal frequency of seropositive IgG anti-T gondii antibodies was higher in donors than in recipients (38.4% vs 25.2%; P = .03). During the 12-month follow-up, the accumulated seroconversion to IgG and IgM antibodies was 3/99 (3.0%), and the accumulated reactivation was 11/99 (11.0%). None of the samples exhibited positivity to T gondii DNA. CONCLUSIONS: This study showed that there is an increased risk of seroconversion or reactivation in renal transplant recipients over a 12-month follow-up. Our data suggest that prophylaxis with trimethoprim and sulfamethoxazole effectively prevented toxoplasmosis, since neither T gondii DNA nor clinical toxoplasmosis was detected.


Assuntos
Anticorpos Antiprotozoários/sangue , Doadores de Tecidos/estatística & dados numéricos , Toxoplasmose/diagnóstico , Transplantados/estatística & dados numéricos , DNA de Protozoário , Seguimentos , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Transplante de Rim , Estudos Longitudinais , México , Soroconversão , Toxoplasma/genética
16.
Int J Mol Sci ; 20(6)2019 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-30893806

RESUMO

This study presents the valorization of cotton waste from the textile industry for the development of sustainable and cost-competitive biopolymer composites. The as-received linter of recycled cotton was first chopped to obtain short fibers, called recycled cotton fibers (RCFs), which were thereafter melt-compounded in a twin-screw extruder with partially bio-based polyethylene terephthalate (bio-PET) and shaped into pieces by injection molding. It was observed that the incorporation of RCF, in the 1⁻10 wt% range, successfully increased rigidity and hardness of bio-PET. However, particularly at the highest fiber contents, the ductility and toughness of the pieces were considerably impaired due to the poor interfacial adhesion of the fibers to the biopolyester matrix. Interestingly, RCF acted as an effective nucleating agent for the bio-PET crystallization and it also increased thermal resistance. In addition, the overall dimensional stability of the pieces was improved as a function of the fiber loading. Therefore, bio-PET pieces containing 3⁻5 wt% RCF presented very balanced properties in terms of mechanical strength, toughness, and thermal resistance. The resultant biopolymer composite pieces can be of interest in rigid food packaging and related applications, contributing positively to the optimization of the integrated biorefinery system design and also to the valorization of textile wastes.


Assuntos
Materiais Biocompatíveis/química , Materiais Biocompatíveis/economia , Custos e Análise de Custo , Fibra de Algodão/economia , Polietilenotereftalatos/química , Varredura Diferencial de Calorimetria , Módulo de Elasticidade , Fenômenos Mecânicos , Reciclagem , Temperatura , Termogravimetria
17.
Ann Diagn Pathol ; 33: 58-61, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29566949

RESUMO

Secretory carcinoma (SC) is a rare low-grade malignant tumor, defined by ETV6-NTRK3 fusion, identifiable by FISH. We describe a case in a 58-year-old male with a painless slowly growing 16mm palpable mass within left superficial parotid. FNA of the mass showed highly cellular specimen with moderate to large pleomorphic cells with round to ovoid nuclei with vesicular chromatin and distinct nucleoli. Cells had moderate to large amounts of vacuolated cytoplasm. Abundant globular metachromatic material, resembling that of adenoid cystic carcinoma, was noted. This material was seen extracellularly and intracytoplasmic, and stained magenta on Diff-Quik and blue-green on Papanicolaou-stained slides. The tumor cells on a cell block preparation were positive for Mammaglobin and S-100. PAS stain highlighted extracellular and intracytoplasmic secretions. FNA diagnosis was "Positive for Malignancy. Morphologic features most compatible with Mammary Analogue Secretory Carcinoma". ETV6 FISH studies as well as histologic examination of excised tumor confirmed the diagnosis. Finding the globular metachromatic material in SC, that is generally seen in adenoid cystic carcinoma, broadens a cytological differential diagnosis of both entities. Cytological differential diagnosis, clinical, histological, immunohistochemical, and molecular features of secretory carcinomas are discussed in this study.


Assuntos
Neoplasias da Mama/patologia , Carcinoma Adenoide Cístico/patologia , Carcinoma Mucoepidermoide/patologia , Carcinoma/patologia , Carcinoma Secretor Análogo ao Mamário/patologia , Biomarcadores Tumorais/análise , Neoplasias da Mama/diagnóstico , Carcinoma/diagnóstico , Carcinoma Adenoide Cístico/diagnóstico , Carcinoma Mucoepidermoide/diagnóstico , Diagnóstico Diferencial , Humanos , Masculino , Carcinoma Secretor Análogo ao Mamário/diagnóstico , Pessoa de Meia-Idade
18.
Appl Opt ; 56(28): 7869-7876, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-29047772

RESUMO

We present an alignment technique that exploits angular correlations by employing a pair of masks, which encode in an angular format pseudo-random sequences. The angular correlator generates peaked irradiance distributions on-axis, provided that the elements of the pair are aligned. Otherwise, the on-axis irradiance distribution decreases to a minimum value. Since the proposed angular correlator is independent of the lateral magnification, it is useful for testing the performance of varifocal lenses. A merit function describes the tolerance to focus errors associated with the location of a small size detector. We use linearly polarized films for showing that the technique also works well with broad band light.

20.
Am J Dermatopathol ; 37(11): 809-21, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26485238

RESUMO

Sebaceous carcinoma (SC) is a relatively uncommon malignant epithelial neoplasm with a predilection for the periocular region. The diagnosis of SC can be difficult to make at initial presentation, as it can clinically and histopathologically resemble other common benign and malignant epithelial lesions. A diagnosis of SC is made by confirmation of sebaceous differentiation of neoplastic cells, which can often be accomplished by conventional microscopic findings; however, its recognition may be sometimes difficult and requires ancillary studies such as immunohistochemistry (IHC). Many studies have evaluated the role of IHC as a potential technique to differentiate SC from its mimics; however, most of these studies have used a limited panel of antibodies with variable results. The aim of this study was to determine the efficacy of IHC in the diagnosis of SC and to provide some guidelines for interpretation in the diagnosis of these neoplasms. We studied 27 cases of SC with a broad panel of IHC markers using a tissue microarray technique. We also studied 21 control cases of basal cell carcinoma (BCC) and 22 control cases of squamous cell carcinoma (SCC). Representative tissue cores were taken and processed from each case, and the tissue microarrays were stained by standard methods using antibodies to EMA, CK7, Ber-EP4, Factor XIIIA, androgen receptor, p53, adipophilin, progesterone receptor membrane component 1 (PGRMC1), squalene synthase (SQS), and alpha/beta hydrolase domain-containing protein 5 (ABHD5). Our studies show that EMA was expressed in all cases of SC, CK7 was expressed in 24 of 27 cases, Ber-EP4 was expressed in 7 of 27 cases, Factor XIIIA was negative in all cases, androgen receptor was expressed in 9 of 27 cases, P53 was expressed in 12 of 27 cases, adipophilin was expressed in all cases, PGRMC1 was expressed in 22 of 27 cases, SQS was expressed in 11 of 27 cases, and ABHD5 was expressed in 9 of 27 cases. EMA was negative in all cases of BCC, CK7 was expressed in 6 of 21 cases, Ber-EP4 was expressed in 21 of 21 cases, Factor XIIIA was negative in all cases, androgen receptor was expressed in 3 of 21 cases, P53 was expressed in 4 of 21 cases, adipophilin, PGRMC1, SQS, and ABHD5 were negative in all cases of BCC. Similarly, EMA was expressed in 16 of 22 cases of SCC, CK7 was expressed in 2 of 22 cases, Ber-EP4, Factor XIIIA, and androgen receptor were negative in all cases, P53 was expressed in 3 of 22 cases, adipophilin, PGRMC1, SQS, and ABHD5 were negative in all cases of SCC. Our study indicates that adipophilin represents a sensitive and reliable marker for the diagnosis of SC and can be of help in separating this tumor from some of its mimics. Additionally, inclusion of various epithelial markers in the panel will be of help if adequately used. Other antibodies against the PAT family of lipid droplet-associated proteins including PGRMC1, SQS, and ABHD5 were not as sensitive as adipophilin for identifying sebaceous differentiation and may therefore not be as useful for differential diagnosis as adipophilin.


Assuntos
Adenocarcinoma Sebáceo/diagnóstico , Imuno-Histoquímica/métodos , Neoplasias das Glândulas Sebáceas/diagnóstico , Adulto , Idoso , Biomarcadores Tumorais/análise , Carcinoma Basocelular/diagnóstico , Carcinoma de Células Escamosas/diagnóstico , Diagnóstico Diferencial , Feminino , Humanos , Imunofenotipagem/métodos , Masculino , Pessoa de Meia-Idade , Neoplasias Cutâneas/diagnóstico , Análise Serial de Tecidos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA