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1.
Molecules ; 24(17)2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31466247

RESUMO

This is the first study on the effect of carbonic maceration on the quality (color, aroma profile and sensory properties) of Muscat Hamburg, contrasting two winemaking procedures used in Tianjin (classical white and red-winemaking techniques). The values of C* (psychometric chroma), a* (measure of redness) and b* (measure of yellowness) were significantly higher (p < 0.01) in the carbonic macerated wine than in red wine. However, there were no visual differences in color, and classical red wine and carbonic macerated wine had similar h (hue angle) values and located in the red region. Thirty-two aromatic compounds were identified and quantified in Muscat Hamburg wines. The content of volatile compounds (6384.97 µg/L) was significantly higher (p < 0.001) in the carbonic macerated Muscat Hamburg wine than in the other kinds of wine. This result led to the carbonic macerated wine having the highest odor activity values (OAVs) and sensory evaluation scores (86.8 points), which correlates with an "excellent" sensory perception. This study demonstrated that carbonic maceration significantly improved the quality of Muscat Hamburg wine based on volatile analysis and sensory evaluation compared with other conventional methods. Therefore, carbonic maceration could be well suited for making Muscat Hamburg wine.

2.
Medicine (Baltimore) ; 98(26): e16203, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31261566

RESUMO

RATIONALE: Essential thrombocytosis (ET) is a myeloproliferative neoplasm characterized by clonal proliferation of the megakaryocytic lineage within the bone marrow and phenotypically by an elevated platelet count in peripheral blood. Common vascular complications include thrombosis, microvascular disturbances, and hemorrhage. ET with recurrent spontaneous abortion as the primary symptom is rare. PATIENT CONCERNS: A 30-year-old pregnant woman (gestational age: 8 weeks) with a history of recurrent spontaneous abortion in the mid trimester was admitted to our hospital for further management. DIAGNOSIS: The diagnosis of ET was made based on the platelet count, bone marrow biopsy, and molecular biology testing. INTERVENTIONS: The patient was treated with interferon, heparin, and aspirin. OUTCOMES: The infant was delivered by cesarean section without complication at 28 weeks gestation due to placental abruption. The child remained healthy with no developmental abnormalities during follow-up for 2 years. LESSONS: Recurrent spontaneous abortion in the mid trimester might be associated with ET. Thus, a detailed investigation including blood routine examination to identify an abnormal platelet count is warranted for pregnant patients with such a history in order to facilitate timely treatment.


Assuntos
Aborto Espontâneo/diagnóstico , Trombocitemia Essencial/diagnóstico , Aborto Espontâneo/genética , Aborto Espontâneo/patologia , Adulto , Medula Óssea/patologia , Cesárea , Diagnóstico Diferencial , Feminino , Humanos , Gravidez , Primeiro Trimestre da Gravidez , Trombocitemia Essencial/genética , Trombocitemia Essencial/patologia , Trombocitemia Essencial/terapia
3.
Angew Chem Int Ed Engl ; 58(33): 11434-11438, 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-31166066

RESUMO

The utilization of 5-hydroxymethyl furfural (HMF) as a renewable feedstock for polymer synthesis has not yet been achieved as it is structurally asymmetric and contains three active functional groups. Reported here is the unprecedented step-growth copolymerization of HMF and dihydrosilanes, through a coordination mechanism, to afford linear poly(silyl ether)s in the presence of B(C6 F5 )3 and the heteroscorpionate zinc hydride complex LZnH [L=(Me Pz)2 CP(Ph)2 NPh, Me Pz=3,5-dimethylpyrazolyl]. The adduct B(C6 F5 )3 ⋅⋅⋅H⋅⋅⋅Zn, confirmed by NMR spectroscopy and DFT calculations, plays a key role in the synergistic catalysis, where B(C6 F5 )3 activates ZnH and stabilizes the Zn+ active species, and the sterically bulky ZnH effectively inhibits (C6 F5 )3 B from reacting with dihydrosilane to form (C6 F5 )3 B-H-Si, which facilely initiates ring opening of furan. The mechanism was studied by DFT simulations.

4.
Protein Cell ; 2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31134525

RESUMO

Neuropsychiatric disorders are complex disorders characterized by heterogeneous genetic variations, variable symptoms, and widespread changes in anatomical pathology. In the context of neuropsychiatric disorders, limited access to relevant tissue types presents challenges for understanding disease etiology and developing effective treatments. Induced pluripotent stem cells (iPSCs) reprogrammed from patient somatic cells offer an opportunity to recapitulate disease development in relevant cell types, and they provide novel approaches for understanding disease mechanisms and for development of effective treatments. Here we review recent progress and challenges in differentiation paradigms for generating disease-relevant cells and recent studies of neuropsychiatric disorders using human pluripotent stem cell (hPSC) models where cellular phenotypes linked to disease have been reported. The use of iPSC-based disease models holds great promise for understanding disease mechanisms and supporting discovery of effective treatments.

5.
Stem Cells ; 37(9): 1158-1165, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31145821

RESUMO

Human embryonic stem cells (hESCs) depend on glycolysis for energy supply and pluripotency and switch to oxidative phosphorylation upon differentiation. The underlying mechanisms remain unclear. Here, we demonstrate that indoleamine 2,3-dioxygenase 1 (IDO1) is expressed in primed hESCs and its expression rapidly downregulated upon hESC differentiation. IDO1 is required to maintain pluripotency by suppressing mitochondria activity and promoting glycolysis through the increase of NAD+ /NADH ratio. The upregulation of IDO1 during hESC differentiation suppresses the differentiation of hESCs into certain lineages of cells such as cardiomyocytes, which depend on oxidative phosphorylation to satisfy their high energy demand. Therefore, IDO1 plays important roles in maintaining the pluripotency of hESCs. Stem Cells 2019;37:1158-1165.

6.
Molecules ; 24(4)2019 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-30813233

RESUMO

Oxidative stress leads to various diseases, including diabetes, cardiovascular diseases, neurodegenerative diseases, and even cancer. The dietary flavonol glycoside, hyperoside (quercetin-3-O-galactoside), exerts health benefits by preventing oxidative damage. To further understand its antioxidative defence mechanisms, we systemically investigated the regulation of hyperoside on oxidative damage induced by hydrogen peroxide, carbon tetrachloride, and cadmium in Saccharomyces cerevisiae. Hyperoside significantly increased cell viability, decreased lipid peroxidation, and lowered intracellular reactive oxygen species (ROS) levels in the wild-type strain (WT) and mutants gtt1∆ and gtt2∆. However, the strain with ctt1∆ showed variable cell viability and intracellular ROS-scavenging ability in response to the hyperoside treatment upon the stimulation of H2O2 and CCl4. In addition, hyperoside did not confer viability tolerance or intercellular ROS in CdSO4-induced stress to strains of sod1∆ and gsh1∆. The results suggest that the antioxidative reactions of hyperoside in S. cerevisiae depend on the intercellular ROS detoxification system.


Assuntos
Antioxidantes/farmacologia , Flavonoides/farmacologia , Proteínas Fúngicas/genética , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Cádmio/toxicidade , Tetracloreto de Carbono/toxicidade , Peróxido de Hidrogênio/toxicidade , Peroxidação de Lipídeos/efeitos dos fármacos , Viabilidade Microbiana , Modelos Biológicos , Mutação , Estresse Oxidativo/efeitos dos fármacos , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/genética
7.
Appl Biochem Biotechnol ; 189(1): 65-75, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30863987

RESUMO

Corn stover silage (CSS) is regarded as a promising feedstock for bioethanol production. The two-step pretreatment using a sequential non-ionic surfactant and ferric nitrate pretreatment was investigated for improving the enzymatic hydrolysis of CSS. The first-step pretreatment using non-ionic surfactant (Tween-80, 2.0 wt.%) at 60 °C for 60 min achieved 30.48% the removal of lignin. Compared with the raw material, the cellulose content of first-step treated CSS increased by 15.86%. The second step using ferric nitrate resulted in 94.56% hemicellulose removal and achieved 72.53% cellulose purity at 130 °C for 30 min, while the yields of furfural and HMF were only 0.36 and 0.32 g/100 g dry material, respectively. The maximum enzymatic digestibility of the two-step treated CSS was 90.98% with a low cellulose dosage (15 FPU/g-glucan), which was approximately 32.07% higher than that of the first-step pretreatment only with Tween-80.


Assuntos
Celulase/química , Celulose/química , Compostos Férricos/química , Nitratos/química , Silagem , Açúcares/isolamento & purificação , Tensoativos/química , Zea mays/química
8.
Nat Neurosci ; 22(3): 333-334, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30796420
9.
Proc Natl Acad Sci U S A ; 115(29): E6722-E6730, 2018 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-29967137

RESUMO

The ability to control the activity of CRISPR-dCas9 with precise spatiotemporal resolution will enable tight genome regulation of user-defined endogenous genes for studying the dynamics of transcriptional regulation. Optogenetic devices with minimal phototoxicity and the capacity for deep tissue penetration are extremely useful for precise spatiotemporal control of cellular behavior and for future clinic translational research. Therefore, capitalizing on synthetic biology and optogenetic design principles, we engineered a far-red light (FRL)-activated CRISPR-dCas9 effector (FACE) device that induces transcription of exogenous or endogenous genes in the presence of FRL stimulation. This versatile system provides a robust and convenient method for precise spatiotemporal control of endogenous gene expression and also has been demonstrated to mediate targeted epigenetic modulation, which can be utilized to efficiently promote differentiation of induced pluripotent stem cells into functional neurons by up-regulating a single neural transcription factor, NEUROG2 This FACE system might facilitate genetic/epigenetic reprogramming in basic biological research and regenerative medicine for future biomedical applications.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/biossíntese , Sistemas CRISPR-Cas , Diferenciação Celular , Reprogramação Celular , Epigênese Genética , Luz , Proteínas do Tecido Nervoso/biossíntese , Neurônios/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Células HEK293 , Células HeLa , Humanos , Proteínas do Tecido Nervoso/genética , Neurônios/citologia , Optogenética/métodos , Biologia Sintética
10.
Chem Biol Drug Des ; 92(3): 1647-1656, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29745030

RESUMO

α-Glucosidase is known to catalyze the digestion of carbohydrates and release free glucose into the digestive tract. Protein tyrosine phosphatase 1B (PTP1B) is engaged in the dephosphorylation of the insulin receptor and regulation of insulin sensitivity. Therefore, dual antagonists by targeting both α-glucosidase and PTP1B may be potential candidates for type 2 diabetes therapy. In this work, three series of novel N-aryl-ω-(benzoazol-2-yl)-sulfanylalkanamides were synthesized and assayed for their α-glucosidase and PTP1B inhibitory activities, respectively. Compound 3l, exhibiting the most effective α-glucosidase inhibitory activity (IC50  = 10.96 µm (3l), IC50  = 51.32 µm (Acarbose), IC50  = 18.22 µm (Ursolic acid)) and potent PTP1B inhibitory activity (IC50  = 13.46 µm (3l), IC50  = 14.50 µm (Ursolic acid)), was identified as a novel dual inhibitor of α-glucosidase and PTP1B. Furthermore, 3l is a highly selective PTP1B inhibitor because no inhibition was showed by 3l at 100 µm against PTP-MEG2, TCPTP, SHP2, or SHP1. Subsequent kinetic analysis revealed 3l inhibited α-glucosidase in a reversible and mixed manner. Molecular docking study indicated that hydrogen bonds, van der Waals, charge interactions and Pi-cation interactions all contributed to affinity between 3l and α-glucosidase/PTP1B.

11.
Proc Natl Acad Sci U S A ; 115(16): 4045-4050, 2018 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-29666318

RESUMO

China's croplands have experienced drastic changes in management practices, such as fertilization, tillage, and residue treatments, since the 1980s. There is an ongoing debate about the impact of these changes on soil organic carbon (SOC) and its implications. Here we report results from an extensive study that provided direct evidence of cropland SOC sequestration in China. Based on the soil sampling locations recorded by the Second National Soil Survey of China in 1980, we collected 4,060 soil samples in 2011 from 58 counties that represent the typical cropping systems across China. Our results showed that across the country, the average SOC stock in the topsoil (0-20 cm) increased from 28.6 Mg C ha-1 in 1980 to 32.9 Mg C ha-1 in 2011, representing a net increase of 140 kg C ha-1 year-1 However, the SOC change differed among the major agricultural regions: SOC increased in all major agronomic regions except in Northeast China. The SOC sequestration was largely attributed to increased organic inputs driven by economics and policy: while higher root biomass resulting from enhanced crop productivity by chemical fertilizers predominated before 2000, higher residue inputs following the large-scale implementation of crop straw/stover return policy took over thereafter. The SOC change was negatively related to N inputs in East China, suggesting that the excessive N inputs, plus the shallowness of plow layers, may constrain the future C sequestration in Chinese croplands. Our results indicate that cropland SOC sequestration can be achieved through effectively manipulating economic and policy incentives to farmers.


Assuntos
Agricultura/métodos , Sequestro de Carbono , Carbono/análise , Conservação dos Recursos Naturais/legislação & jurisprudência , Compostos Orgânicos/análise , Políticas , Solo/química , Agricultura/economia , Agroquímicos/química , China , Compostagem , Conservação dos Recursos Naturais/economia , Conservação dos Recursos Naturais/estatística & dados numéricos , Produtos Agrícolas/química , Fazendas , Atividades Humanas , Humanos , Dispersão Vegetal , Raízes de Plantas/química , Caules de Planta/química , Plantas/química , Mudança Social , Microbiologia do Solo
12.
J Agric Food Chem ; 66(12): 3155-3160, 2018 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-29526093

RESUMO

Aging and oxidative-related events are closely associated with the oxidative damages induced by excess reactive oxygen species (ROS). The phytochemicals nobiletin (NBT) and tangeretin (TAN) and their 5-demethylated derivatives 5-demethylnobiletin (5-DN) and 5-demethyltangeretin (5-DT) are the representative polymethoxyflavone (PMF) compounds found in aged citrus peels. Although the health benefits from PMFs due to their antioxidant activities have been well documented, a systematic assessment regarding the antioxidation process of PMFs is still lacking attention. Herein, we investigated the effects of the four PMFs subjected to oxidative stress including hydrogen peroxide, carbon tetrachloride, and cadmium sulfate using an emerging model organism Saccharomyces cerevisiae. As expected, all four of the PMFs exhibited improved cellular tolerance with decreasing lipid peroxidation and ROS. Furthermore, by using the mutant strains deficient in catalase, superoxide dismutase, or glutathione synthase, NBT, 5-DN, and TAN appear to contribute to the increased tolerance by activating cytosolic catalase under CCl4, while the antioxidant protection conferred by 5-DT against H2O2 and CdSO4 seems to require cytosolic catalase and glutathione, respectively. However, the involvement of Ctt1 and Sod1 is achieved neither by decreasing lipid peroxidation nor by scavenging intracellular ROS according to our results. In addition, a comparison of antioxidant capability of the four PMFs was conducted in this study. In general, this research tries to explore the antioxidant mechanism of PMFs in Saccharomyces cerevisiae, hoping to provide an example for developing more efficacious dietary antioxidants to battle against oxidative- or age-related illness.


Assuntos
Antioxidantes/farmacologia , Citrus/química , Flavonas/farmacologia , Extratos Vegetais/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Antioxidantes/química , Flavonas/química , Glutationa/metabolismo , Peróxido de Hidrogênio/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/química , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Superóxido Dismutase/metabolismo
13.
Biotechnol J ; 13(5): e1700160, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29144600

RESUMO

Synthetic biology applies engineering principles to biological systems and has significantly advanced the design of synthetic gene circuits that can reprogram cell activities to perform new functions. The ability to engineer mammalian designer cells with robust therapeutic behaviors has brought new opportunities for treating metabolic diseases. In this review, the authors highlight the most recent advances in the development of synthetic designer cells uploaded with open- or closed-loop gene circuits for the treatment of metabolic disorders including diabetes, hypertension, hyperuricemia, and obesity, and discuss the current technologies and future perspectives in applying these designer cells for clinical applications. In the future, more and more rationally designed cells will be constructed and revolutionized to treat a number of metabolic disorders in an intelligent manner.


Assuntos
Engenharia Celular , Terapia Baseada em Transplante de Células e Tecidos , Redes Reguladoras de Genes , Doenças Metabólicas/terapia , Biologia Sintética , Animais , Diabetes Mellitus/terapia , Humanos , Camundongos
14.
Chemistry ; 23(72): 18151-18155, 2017 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-29205544

RESUMO

Fluoromonomers are difficult to polymerize through a coordination mechanism owing to the strong chelation between fluorine and catalysts and the electron-deficient double-bond. We report herein the unprecedented polymerization of para-fluorostyrene (pFS) with excellent activity (1.12×107  g molLn-1 h-1 ), distinguished syndioselectivity (rrrr >99 %) and high conversion (98.4 %) using rare-earth-metal catalysts bearing a pyridyl methylene fluorenyl ligand. DFT calculations reveal polar fluorine loses overwhelming coordination priority to the active central metal ion due to the sterically bulky and electron-donating CGC-ligand, thus its power of poisoning the active species is dramatically weakened. Based on this, copolymerization of pFS and styrene (St) has been successfully achieved with high activity and controllable pFS insertion. Conversely, the unlinked half-sandwich rare-earth-metal system shows relatively lower activity, because both the transition-states and intermediates incorporate a µ1 -F chelated pFS.

15.
Int J Mol Med ; 40(4): 1047-1056, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28902356

RESUMO

Upregulation or downregulation of microRNAs (miRNAs) has been identified in human cervical cancer (CC). However, the character and function of miR-378 in CC remains unknown. In the present study, the authors demonstrated that miR-378 was upregulated in CC used the reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) assay, and promoted cell proliferation by accelerating the progress of cell cycle and repressing cell apoptosis in CC cells. The predicted target genes of miR-378 were determined by enhanced green fluorescent protein (EGFP) reporter assays, RT-qPCR assay and western blot analysis. miR-378 suppressed the expression of suppression of tumorigenicity 7-like (ST7L) by targeting the 3'-untranslated region (3'-UTR) of ST7L mRNA in HeLa and SiHa cells. ST7L was downregulated in CC using the RT-qPCR assay, and the malignant phenotype of HeLa and SiHa cells were inhibited by ST7L overexpression. In addition, miR-378 activated the Wnt/ß-catenin pathway by targeting ST7L in CC cells. In short, miR-378 functions as an onco-miRNA by directly downregulating ST7L mRNA and protein level in HeLa and SiHa cells, and serves important roles in the malignancy of CC.


Assuntos
MicroRNAs/metabolismo , Proteínas de Ligação a RNA/genética , Neoplasias do Colo do Útero/genética , Via de Sinalização Wnt/genética , Apoptose/genética , Sequência de Bases , Ciclo Celular/genética , Proliferação de Células/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Células HeLa , Humanos , MicroRNAs/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/metabolismo , Regulação para Cima/genética , Neoplasias do Colo do Útero/patologia
16.
Sheng Wu Gong Cheng Xue Bao ; 33(3): 436-455, 2017 Mar 25.
Artigo em Chinês | MEDLINE | ID: mdl-28941342

RESUMO

Although still in its infant stage, synthetic biology has achieved remarkable development and progress during the past decade. Synthetic biology applies engineering principles to design and construct gene circuits uploaded into living cells or organisms to perform novel or improved functions, and it has been widely used in many fields. In this review, we describe the recent advances of mammalian synthetic biology for the treatment of diseases. We introduce common tools and design principles of synthetic gene circuits, and then we demonstrate open-loop gene circuits induced by different trigger molecules used in disease diagnosis and close-loop gene circuits used for biomedical applications. Finally, we discuss the perspectives and potential challenges of synthetic biology for clinical applications.


Assuntos
Engenharia Biomédica , Redes Reguladoras de Genes , Biologia Sintética , Animais , Humanos , Mamíferos
17.
BMC Ophthalmol ; 17(1): 95, 2017 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-28629400

RESUMO

BACKGROUND: To describe the characteristics of patients with syphilitic uveitis in northern China. METHODS: A case series of 21 patients (33 eyes) diagnosed with syphilitic uveitis from 2011 to 2016 at a tertiary center in northern China was retrospectively analyzed. RESULTS: Twenty-one patients (33 eyes) were diagnosed as syphilitic uveitis. Posterior segment involvement was found in 32 eyes (97.0%). Vitreous haze, neuroretinitis, and posterior placoid chorioretinitis were mainly found in patients with a relatively short duration of the disease, while diffuse chorioretinitis, pseudoretinitis pigmentosa, cystoid macular edema, and epiretinal membrane were found in patients with relatively long duration of ocular involvement. A low best-corrected visual acuity (P = 0.022) and a delay of syphilis treatment (P < 0.001) were associated with a significantly worse visual outcome. CONCLUSIONS: Syphilitic uveitis should be included in the differential diagnosis of any form of posterior ocular inflammation. The pattern of ocular involvement may change with the disease progression.


Assuntos
Infecções Oculares Bacterianas/diagnóstico , Angiofluoresceinografia/métodos , Sífilis/diagnóstico , Tomografia de Coerência Óptica/métodos , Uveíte/diagnóstico , Adulto , China/epidemiologia , Diagnóstico Diferencial , Infecções Oculares Bacterianas/epidemiologia , Feminino , Fundo de Olho , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Sífilis/epidemiologia , Uveíte/epidemiologia , Acuidade Visual , Adulto Jovem
18.
Sci Rep ; 7(1): 3440, 2017 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-28611362

RESUMO

Surface-modified metal implants incorporating different ions have been employed in the biomedical field as bioactive dental implants with good osseointegration properties. However, the molecular mechanism through which surface coatings exert the biological activity is not fully understood, and the effects have been difficult to achieve, especially in the osteopenic bone. In this study, We examined the effect of zinc-modified calcium silicate coatings with two different Zn contents to induce osteogenic differentiation of rat bone marrow-derived pericytes (BM-PCs) and osteogenetic efficiency in ovariectomised rabbits. Ti-6Al-4V with zinc-modified calcium silicate coatings not only enhanced proliferation but also promoted osteogenic differentiation and mineralized matrix deposition of rat BM-PCs as the zinc content and culture time increased in vitro. The associated molecular mechanisms were investigated by Q-PCR and Western blotting, revealing that TGF-ß/Smad signaling pathway plays a direct and significant role in regulating BM-PCs osteoblastic differentiation on Zn-modified coatings. Furthermore, in vivo results that revealed Zn-modified calcium silicate coatings significantly promoted new bone formation around the implant surface in osteopenic rabbits as the Zn content and exposure time increased. Therefore, Zn-modified calcium silicate coatings can improve implant osseointegration in the condition of osteopenia, which may be beneficial for patients suffering from osteoporosis-related fractures.

19.
Angew Chem Int Ed Engl ; 56(24): 6975-6979, 2017 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-28471072

RESUMO

Introducing ethylene units into polybutadiene backbones is an approach to synthesize advanced rubber materials, which has been a research challenge because of distinct polymerization mechanisms of the two monomers. To date, only trans-1,4- and 1,2-regulated copolymers have been obtained. Herein, we reported the unprecedented cis-1,4 selective copolymerization of ethylene and butadiene by using the thiophene-fused cyclopentadienyl-ligated scandium complexes. The effects of the sterics and electronics of the catalytic precursors as well as the monomer loading mode on the activity and selectivity as well as the sequence lengths were investigated, and the mechanism was elucidated. Thus a novel ethylene-based rubber material possessing a high molecular weight, 80 % cis-1,4 regularity and a Tg =-94 °C without an obvious melting point owing to short polyethylene sequences even at its content up to 45 mol %, was isolated. This new rubber material exhibited excellent anti-flowing performance and strong tensile strength.

20.
Mol Phylogenet Evol ; 112: 268-276, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28414099

RESUMO

Cotton (Gossypium spp.) is commonly grouped into eight diploid genomic groups, designated A-G and K, and one tetraploid genomic group, namely AD. To gain insight into the phylogeny of Gossypium and molecular evolution of the chloroplast genome duringdiversification, chloroplast genomes (cpDNA) from 6 D-genome and 2 G-genome species of Gossypium (G. armourianum D2-1, G. harknessii D2-2, G. davidsonii D3-d, G. klotzschianum D3-k, G. aridum D4, G. trilobum D8, and G. australe G2, G. nelsonii G3) were newly reported here. In combination with the 26 previously released cpDNA sequences, we performed comparative phylogenetic analyses of 34 Gossypium chloroplast genomes that collectively represent most of the diversity in the genus. Gossypium chloroplasts span a small range in size that is mostly attributable to indels that occur in the large single copy (LSC) region of the genome. Phylogenetic analysis using a concatenation of all genes provides robust support for six major Gossypium clades, largely supporting earlier inferences but also revealing new information on intrageneric relationships. Using Theobroma cacao as an outgroup, diversification of the genus was dated, yielding results that are in accord with previous estimates of divergence times, but also offering new perspectives on the basal, early radiation of all major clades within the genus as well as gaps in the record indicative of extinctions. Like most higher-plant chloroplast genomes, all cotton species exhibit a conserved quadripartite structure, i.e., two large inverted repeats (IR) containing most of the ribosomal RNA genes, and two unique regions, LSC (large single sequence) and SSC (small single sequence). Within Gossypium, the IR-single copy region junctions are both variable and homoplasious among species. Two genes, accD and psaJ, exhibited greater rates of synonymous and non-synonymous substitutions than did other genes. Most genes exhibited Ka/Ks ratios suggestive of neutral evolution, with 8 exceptions distributed among one to several species. This research provides an overview of the molecular evolution of a single, large non-recombining molecular during the diversification of this important genus.


Assuntos
Evolução Molecular , Variação Genética , Genoma de Cloroplastos , Gossypium/genética , Análise de Variância , DNA de Cloroplastos/genética , Dosagem de Genes , Especiação Genética , Tamanho do Genoma , Mutação INDEL/genética , Funções Verossimilhança , Nucleotídeos/genética , Fases de Leitura Aberta/genética , Filogenia , Especificidade da Espécie
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