Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
Mais filtros

Base de dados
País como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Proc Natl Acad Sci U S A ; 120(42): e2306710120, 2023 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-37824525

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic and the measures taken by authorities to control its spread have altered human behavior and mobility patterns in an unprecedented way. However, it remains unclear whether the population response to a COVID-19 outbreak varies within a city or among demographic groups. Here, we utilized passively recorded cellular signaling data at a spatial resolution of 1 km × 1 km for over 5 million users and epidemiological surveillance data collected during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron BA.2 outbreak from February to June 2022 in Shanghai, China, to investigate the heterogeneous response of different segments of the population at the within-city level and examine its relationship with the actual risk of infection. Changes in behavior were spatially heterogenous within the city and population groups and associated with both the infection incidence and adopted interventions. We also found that males and individuals aged 30 to 59 y old traveled more frequently, traveled longer distances, and their communities were more connected; the same groups were also associated with the highest SARS-CoV-2 incidence. Our results highlight the heterogeneous behavioral change of the Shanghai population to the SARS-CoV-2 Omicron BA.2 outbreak and the effect of heterogenous behavior on the spread of COVID-19, both spatially and demographically. These findings could be instrumental for the design of targeted interventions for the control and mitigation of future outbreaks of COVID-19, and, more broadly, of respiratory pathogens.


Assuntos
COVID-19 , Masculino , Humanos , COVID-19/epidemiologia , China/epidemiologia , SARS-CoV-2 , Surtos de Doenças , Processos Grupais
2.
J Org Chem ; 88(15): 10818-10827, 2023 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-37482947

RESUMO

A heterogeneous redox-neutral palladium-catalytic platform was reported for the preparation of deuterated (hetero) arenes from (hetero) arenes mediated by regioselective C(sp2)-H thianthrenation utilizing commercially available and recyclable Pd/C catalyst. A wide range of deuterated compounds could be obtained in high yields with excellent levels of deuterium incorporation under these simple heterogeneous catalytic conditions with the requirement of stable and easily handled DCOONa as a deuterium source. The late-stage deuteration of pharmaceuticals and bioactive molecules was also achieved by this approach.

3.
Theor Appl Genet ; 135(12): 4183-4195, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36068440

RESUMO

KEY MESSAGE: A major and stable QTL cQSGR.sau.3D, which can explain 33.25% of the phenotypic variation in SGR, was mapped and validated, and cQSGR.sau.3D was found to be independent of GI. In this study, a recombinant inbred line (RIL) population containing 304 lines derived from the cross of Chuan-nong17 (CN17) and Chuan-nong11 (CN11) was genotyped using the Wheat55K single-nucleotide polymorphism array. A high-density genetic map consisting of 8329 markers spanning 4131.54 cM and distributed across 21 wheat chromosomes was constructed. QTLs for whole spike germination rate (SGR) were identified in multiple years. Six and fourteen QTLs were identified using the Inclusive Composite Interval Mapping-Biparental Populations and Multi-Environment Trial methods, respectively. A total of 106 digenic epistatic QTLs were also detected in this study. One of the additive QTLs, cQSGR.sau.3D, which was mapped in the region from 3.5 to 4.5 cM from linkage group 3D-2 on chromosome 3D, can explain 33.25% of the phenotypic variation in SGR and be considered a major and stable QTL for SGR. This QTL was independent of the seeds' germination traits, such as germination index. One Kompetitive Allele-Specific PCR (KASP) marker, KASP-AX-110772653, which is tightly linked to cQSGR.sau.3D, was developed. The genetic effect of cQSGR.sau.3D on SGR in the RIL and natural populations was successfully confirmed. Furthermore, within the interval in which cQSGR.sau.3D is located in Chinese Spring reference genomes, thirty-seven genes were found. cQSGR.sau.3D may provide new resources for pre-harvest sprouting resistance breeding of wheat in the future.


Assuntos
Locos de Características Quantitativas , Triticum , Triticum/genética , Mapeamento Cromossômico , Genótipo , Melhoramento Vegetal , Fenótipo , Polimorfismo de Nucleotídeo Único
4.
J Org Chem ; 87(5): 3577-3585, 2022 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-35076240

RESUMO

We report a general, scalable, and convenient photochemical process for diversities of distal oxygenated nitriles from corresponding less-strained ketoxime esters allowing one-step introductions of ether and cyano groups, which avoids the utilization of toxic cyanide reagents. A wide range of ketoxime esters involving five-membered to eight-membered cycloketoxime esters and linear ketoxime esters participate smoothly under operately simple and mild conditions, affording structurally variable ring-opening products.


Assuntos
Ésteres , Éteres , Ésteres/química , Nitrilas/química , Oximas
5.
Proc Natl Acad Sci U S A ; 116(21): 10441-10446, 2019 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-31040209

RESUMO

Polymorphic HLAs form the primary immune barrier to cell therapy. In addition, innate immune surveillance impacts cell engraftment, yet a strategy to control both, adaptive and innate immunity, is lacking. Here we employed multiplex genome editing to specifically ablate the expression of the highly polymorphic HLA-A/-B/-C and HLA class II in human pluripotent stem cells. Furthermore, to prevent innate immune rejection and further suppress adaptive immune responses, we expressed the immunomodulatory factors PD-L1, HLA-G, and the macrophage "don't-eat me" signal CD47 from the AAVS1 safe harbor locus. Utilizing in vitro and in vivo immunoassays, we found that T cell responses were blunted. Moreover, NK cell killing and macrophage engulfment of our engineered cells were minimal. Our results describe an approach that effectively targets adaptive as well as innate immune responses and may therefore enable cell therapy on a broader scale.


Assuntos
Engenharia Genética/métodos , Células-Tronco Pluripotentes/imunologia , Sistemas CRISPR-Cas , Linhagem Celular , Técnicas de Inativação de Genes , Genes MHC Classe I , Genes MHC da Classe II , Humanos
6.
Small Methods ; : e2300213, 2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37381683

RESUMO

Biological macroporous materials, such as stems of the plants and bone of the animals, possess outstanding properties for powerful guarantee of creatures' survival through the well-aligned architecture constructed from limited components. Transition metal carbides or nitrides (MXenes), as novel 2D assemblies, have attracted numerous attentions in various applications due to their unique properties. Therefore, mimicking the bioinspired architecture with MXenes will boost the development of human-made materials with unparalleled properties. Freeze casting has been widely applied to fabricate bioinspired MXene-based materials and achieve the assembly of MXene nanosheets into 3D forms. This process solves the inherent restacking problems of MXenes, simultaneously preserving the unique properties of MXenes with a physical process. Here, the ice-templated assembly of MXene in terms of the freezing processes and their potential mechanisms is summarized. In addition, applications of MXene-based materials in electromagnetic interference shielding and absorption, energy storage and conversion, as well as piezoresistive pressure sensors are also reviewed. Finally, the current challenges and bottlenecks of ice-templated assembly of MXene are further discussed to guide the development of bioinspired MXene-based materials.

7.
Nat Commun ; 14(1): 7855, 2023 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-38030631

RESUMO

Ice formation on solid surfaces is a ubiquitous process in our daily life, and ice orientation plays a critical role in anti-icing/deicing, organ cryo-preservation, and material fabrication. Although previous studies have shown that surface grooves can regulate the orientation of ice crystals, whether the parallel or perpendicular alignment to the grooves is still under debate. Here, we systematically investigate ice formation and its oriented growth on grooved surfaces through both in situ observation and theoretical simulation, and discover a remarkable size effect of the grooves. With the designability of surface groove patterns, the preferential growth of ice crystals is programmed for the fabrication of a crisscross-aligned graphene aerogel with large negative Poisson's ratio. In addition, the size effect provides guidance for the design and fabrication of solid surfaces where the effective control of ice orientation is highly desired, such as efficient deicing, long time organ cryo-preservation, and ice-templated materials.

8.
Bioresour Technol ; 388: 129789, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37741577

RESUMO

A novel magnetic hydrochar derived from cactus cladode (MW-MHC) was successfully synthesized through one-pot microwave-assisted process for efficiently removing lead(Pb)(Ⅱ) and phenol. From batch adsorption experiments, MW-MHC possessed the highest uptake amounts for Pb(Ⅱ) and phenol of 139.34 and 175.32 mg/g within 20 and 60 min, respectively. Moreover, the removal of Pb(Ⅱ) and phenol by MW-MHC remained essentially stable under the interference of different co-existing cations, presenting the excellent adaptability of MW-MHC. After three cycles of regeneration experiments, MW-MHC still had preferable adsorption performance and could be easily recycled, indicating its excellent reusability. Significantly, the uptake mechanisms of Pb(Ⅱ) on MW-MHC were regarded as chemical complexation, pore filling, precipitation, and electrostatic attraction. Meanwhile, the phenol uptake might be dominated by π-π interaction and hydrogen bonding. The above consequences revealed that MW-MHC with high removal performance was a promising adsorbent for remediating wastewater containing heavy metals and organics.


Assuntos
Poluentes Químicos da Água , Água , Chumbo , Fenol , Micro-Ondas , Poluentes Químicos da Água/análise , Adsorção , Fenóis , Cinética
9.
ACS Nano ; 16(9): 14737-14744, 2022 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-35969483

RESUMO

The extraordinary structural and mechanical features of nacre have been widely explored and translated into synthetic layered materials through various methods. However, it still remains challenging to achieve scale-up fabrication of these biomimetic layered materials, which is the main hurdle for their real applications. Herein, we report a facile, universal, and scalable strategy to produce bulk materials with nacre-mimetic architecture and performance. This was realized by the ordered nucleation of ice crystals on a nanogrooved surface. After the infiltration of a polymer, both the specific strength and toughness of our artificial nacre outperform those of natural nacre and other nacre-mimetic materials. Due to the scalability and availability of a nanogrooved surface, large-sized, bulk artificial nacre (30 × 20 × 5 cm) was also obtained through the directional freezing process. In addition, this efficient approach can also be extended to assemble various building blocks like functional nanomaterials such as graphene oxide and MXene nanosheets into bulk porous materials with highly ordered three-dimensional architecture, holding great potential for multifunctional applications.

10.
Org Lett ; 24(32): 6031-6036, 2022 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-35929821

RESUMO

The efficient palladium-catalyzed synthesis of esters from readily available arenes has been developed. These C-H bond esterifications were achieved relying on the regioselective thianthrenation to generate the aryl-TT salts, which were treated as reactive electrophilic substrates to couple with phenol formate and N-hydroxysuccinimide (NHS) formate giving access to phenol esters and NHS esters, respectively, in the absence of carbon monoxide. A wide range of functional esters could be prepared with high efficiency under this redox-neutral palladium-catalytic condition. Late-stage functionalization and investigations of synthetic applications demonstrated the potential application of the established platform and these products.

11.
Org Lett ; 24(26): 4772-4777, 2022 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-35766365

RESUMO

Functional molecules bearing polychlorinated moieties usually play versatile roles in organic synthesis and biochemistry. A copper-catalyzed multicomponent polychloro-carboalkynylation of alkenes presents an efficient and operationally simple approach for the synthesis of ß-polychlorinated alkynes. Mechanistic experiments were conducted demonstrating that an in situ generated copper acetylide complex was the real catalyst and reactive intermediate during the copper-catalytic cycle. And enantioselective exploration demonstrated potential application for the synthesis of chiral ß-polychlorinated alkynes.

12.
Natl Sci Rev ; 8(11): nwab148, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34876997

RESUMO

2020 was an unprecedented year, with rapid and drastic changes in human mobility due to the COVID-19 pandemic. To understand the variation in commuting patterns among the Chinese population across stable and unstable periods, we used nationwide mobility data from 318 million mobile phone users in China to examine the extreme fluctuations of population movements in 2020, ranging from the Lunar New Year travel season (chunyun), to the exceptional calm of COVID-19 lockdown, and then to the recovery period. We observed that cross-city movements, which increased substantially in chunyun and then dropped sharply during the lockdown, are primarily dependent on travel distance and the socio-economic development of cities. Following the Lunar New Year holiday, national mobility remained low until mid-February, and COVID-19 interventions delayed more than 72.89 million people returning to large cities. Mobility network analysis revealed clusters of highly connected cities, conforming to the social-economic division of urban agglomerations in China. While the mass migration back to large cities was delayed, smaller cities connected more densely to form new clusters. During the recovery period after travel restrictions were lifted, the netflows of over 55% city pairs reversed in direction compared to before the lockdown. These findings offer the most comprehensive picture of Chinese mobility at fine resolution across various scenarios in China and are of critical importance for decision making regarding future public-health-emergency response, transportation planning and regional economic development, among others.

13.
J Mech Behav Biomed Mater ; 109: 103820, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32543396

RESUMO

Nacre has achieved an excellent combination of strength and toughness through its unique brick-and-mortar structure of layered aragonite platelets bonded with biopolymers. Mimicking nacre has been considered as a practical way for the development of high-performance structural composites. Over the past years, many techniques have been developed to fabricate multifunctional nacre-mimetic materials, including freeze casting, layer-by-layer assembly, vacuum filtration, 3D printing and so on. Among them, freeze casting, especially bidirectional freeze casting, as an environmentally friendly and scalable method, has attracted extensive attention recently. In this review, we begin with the introduction and discussion of various fabrication techniques comparing their advantages and disadvantages, focusing on the most recent advances of the bidirectional freeze casting technique. Then, we summarize representative examples of applying the bidirectional freeze casting technique to assemble various building blocks into multifunctional nacre-mimetic materials and their wide applications. At the end, we discuss the future direction of using bidirectional freeze casting to make nacre-mimetic materials.


Assuntos
Materiais Biomiméticos , Nácar , Biomimética , Carbonato de Cálcio , Congelamento
15.
Stem Cells Int ; 2017: 6962379, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28197208

RESUMO

Adult acute myeloid leukemia (AML) clinically is a disparate disease that requires intensive treatments ranging from chemotherapy alone to allogeneic hematopoietic cell transplantation (allo-HCT). Historically, cytogenetic analysis has been a useful prognostic tool to classify patients into favorable, intermediate, and unfavorable prognostic risk groups. However, the intermediate-risk group, consisting predominantly of cytogenetically normal AML (CN-AML), itself exhibits diverse clinical outcomes and requires further characterization to allow for more optimal treatment decision-making. The recent advances in clinical genomics have led to the recategorization of CN-AML into favorable or unfavorable subgroups. The relapsing nature of AML is thought to be due to clonal heterogeneity that includes founder or driver mutations present in the leukemic stem cell population. In this article, we summarize the clinical outcomes of relevant molecular mutations and their cooccurrences in CN-AML, including NPM1, FLT3ITD, DNMT3A, NRAS, TET2, RUNX1, MLLPTD, ASXL1, BCOR, PHF6, CEBPAbiallelic, IDH1, IDH2R140, and IDH2R170, with an emphasis on their relevance to the leukemic stem cell compartment. We have reviewed the available literature and TCGA AML databases (2013) to highlight the potential role of stem cell regulating factor mutations on outcome within newly defined AML molecular subgroups.

16.
J Mol Cell Biol ; 9(6): 477-488, 2017 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-29272522

RESUMO

Glioma is a complex disease with limited treatment options. Recent advances have identified isocitrate dehydrogenase (IDH) mutations in up to 80% lower grade gliomas (LGG) and in 76% secondary glioblastomas (GBM). IDH mutations are also seen in 10%-20% of acute myeloid leukemia (AML). In AML, it was determined that mutations of IDH and other genes involving epigenetic regulations are early events, emerging in the pre-leukemic stem cells (pre-LSCs) stage, whereas mutations in genes propagating oncogenic signal are late events in leukemia. IDH mutations are also early events in glioma, occurring before TP53 mutation, 1p/19q deletion, etc. Despite these advances in glioma research, studies into other molecular alterations have lagged considerably. In this study, we analyzed currently available databases. We identified EZH2, KMT2C, and CHD4 as important genes in glioma in addition to the known gene IDH1/2. We also showed that genomic alterations of PIK3CA, CDKN2A, CDK4, FIP1L1, or FUBP1 collaborate with IDH mutations to negatively affect patients' survival in LGG. In LGG patients with TP53 mutations or IDH1/2 mutations, additional genomic alterations of EZH2, KMC2C, and CHD4 individually or in combination were associated with a markedly decreased disease-free survival than patients without such alterations. Alterations of EZH2, KMT2C, and CHD4 at genetic level or protein level could perturb epigenetic program, leading to malignant transformation in glioma. By reviewing current literature on both AML and glioma and performing bioinformatics analysis on available datasets, we developed a hypothetical model on the tumorigenesis from premalignant stem cells to glioma.


Assuntos
Neoplasias Encefálicas/genética , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Epigênese Genética , Glioma/genética , Isocitrato Desidrogenase/genética , Complexo Mi-2 de Remodelação de Nucleossomo e Desacetilase/metabolismo , Neoplasias Encefálicas/patologia , Intervalo Livre de Doença , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Glioma/patologia , Humanos , Isocitrato Desidrogenase/metabolismo , Leucemia Mieloide Aguda/genética , Complexo Mi-2 de Remodelação de Nucleossomo e Desacetilase/genética , Modelos Biológicos , Mutação/genética , Gradação de Tumores , Proteínas de Neoplasias/genética , Células-Tronco/metabolismo , Análise de Sobrevida , Proteína Supressora de Tumor p53/metabolismo
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa