Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.846
Filtrar
1.
Chem Soc Rev ; 50(19): 10764-10805, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34605829

RESUMO

The emerging process of CO2 hydrogenation through heterogenous catalysis into important bulk chemicals provides an alternative strategy for sustainable and low-cost production of valuable chemicals, and brings an important chance for mitigating CO2 emissions. Direct synthesis of the family of unsaturated heavy hydrocarbons such as α-olefins and aromatics via CO2 hydrogenation is more attractive and challenging than the production of short-chain products to modern society, suffering from the difficult control between C-O activation and C-C coupling towards long-chain hydrocarbons. In the past several years, rapid progress has been achieved in the development of efficient catalysts for the process and understanding of their catalytic mechanisms. In this review, we provide a comprehensive, authoritative and critical overview of the substantial progress in the synthesis of α-olefins and aromatics from CO2 hydrogenation via direct and indirect routes. The rational fabrication and design of catalysts, proximity effects of multi-active sites, stability and deactivation of catalysts, reaction mechanisms and reactor design are systematically discussed. Finally, current challenges and potential applications in the development of advanced catalysts, as well as opportunities of next-generation CO2 hydrogenation techniques for carbon neutrality in future are proposed.

2.
Laryngoscope ; 2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34617600

RESUMO

OBJECTIVES: To analyze the clinical features and otologic manifestations of first branchial cleft anomalies (FBCAs) and the disparity between Work's classification, and to explore the relationships between postoperative facial paralysis and features of FBCAs. STUDY DESIGN: Retrospective clinical study. METHODS: A retrospective analysis of 109 patients with FBCAs was conducted, including clinical characteristics and otologic features. Pearson chi-square tests and Fisher's exact tests were used to compare disparity between Work's classification, and the impact factors of postoperative facial paralysis among 86 patients who were explored in follow-up. RESULTS: Patients with FBCAs presented with otologic symptoms, including cysts or fistula in the external auditory canal (EAC) and periauricular (43.2%), microtia (3.7%), EAC web (1.8%), otitis media (1.8%), and otorrhea (4.6%). Eighty-five cases (78.0%) were type I FBCAs and 24 (22.0%) were type II. Compared to type I FBCAs, type II (58.3%) was more likely to be located deep to the facial nerve (FN) and to have superficial parotidectomy on them (79.2%). This difference was statistically significant (P < .001). FBCAs deep to the FN had a higher incidence of postoperative facial paralysis (P < .05). CONCLUSION: The majority of patients (55.0%) had otologic symptoms. The FBCAs of Work type II was commonly deep to the FN and superficial parotidectomy was frequently performed. Postoperative facial paralysis was associated with FBCAs located deep to the FN, but not with Work's type. LEVEL OF EVIDENCE: 4 Laryngoscope, 2021.

3.
Plant Physiol ; 2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34618023

RESUMO

Tomato (Solanum lycopersium), an important fruit crop worldwide, requires efficient sugar allocation for fruit development. However, molecular mechanisms for sugar import to fruits remain poorly understood. Expression of sugars will eventually be exported transporters (SWEETs) proteins is closely linked to high fructose/glucose ratios in tomato fruits and may be involved in sugar allocation. Here, we discovered that SlSWEET15 is highly expressed in developing fruits compared to vegetative organs. In situ hybridization and ß-glucuronidase fusion analyses revealed SlSWEET15 proteins accumulate in vascular tissues and seed coats, major sites of sucrose unloading in fruits. Localizing SlSWEET15-green fluorescent protein to the plasma membrane supported its putative role in apoplasmic sucrose unloading. The sucrose transport activity of SlSWEET15 was confirmed by complementary growth assays in a yeast (Saccharomyces cerevisiae) mutant. Elimination of SlSWEET15 function by clustered regularly interspaced short palindromic repeats (CRISPRs)/CRISPR-associated protein gene editing significantly decreased average sizes and weights of fruits, with severe defects in seed filling and embryo development. Altogether, our studies suggest a role of SlSWEET15 in mediating sucrose efflux from the releasing phloem cells to the fruit apoplasm and subsequent import into storage parenchyma cells during fruit development. Furthermore, SlSWEET15-mediated sucrose efflux is likely required for sucrose unloading from the seed coat to the developing embryo.

4.
Acta Pharmacol Sin ; 2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34593974

RESUMO

Neuroinflammation plays an important role in neurodegenerative diseases, such as Parkinson's disease (PD) and Alzheimer's disease. HACE1 (HECT domain and Ankyrin repeat Containing E3 ubiquitin-protein ligase 1) is a tumor suppressor. Recent evidence suggests that HACE1 may be involved in oxidative stress responses. Due to the critical role of ROS in neuroinflammation, we speculated that HACE1 might participate in neuroinflammation and related neurodegenerative diseases, such as PD. In this study, we investigated the role of HACE1 in neuroinflammation of PD models. We showed that HACE1 knockdown exacerbated LPS-induced neuroinflammation in BV2 microglial cells in vitro through suppressing ubiquitination and degradation of activated Rac1, an NADPH oxidase subunit. Furthermore, we showed that HACE1 exerted vital neuronal protection through increasing Rac1 activity and stability in LPS-treated SH-SY5Y cells, as HACE1 knockdown leading to lower tolerance to LPS challenge. In MPTP-induced acute PD mouse model, HACE1 knockdown exacerbated motor deficits by activating Rac1. Finally, mutant α-synuclein (A53T)-overexpressing mice, a chronic PD mouse model, exhibited age-dependent reduction of HACE1 levels in the midbrain and striatum, implicating that HACE1 participated in PD pathological progression. This study for the first time demonstrates that HACE1 is a negative regulator of neuroinflammation and involved in the PD pathogenesis by regulating Rac1 activity. The data support HACE1 as a potential target for PD and other neurodegenerative diseases.

5.
J Am Chem Soc ; 143(40): 16377-16382, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34596400

RESUMO

The targeted degradation of membrane proteins would afford an attractive and general strategy for treating various diseases that remain difficult with the current proteolysis-targeting chimera (PROTAC) methodology. We herein report a covalent nanobody-based PROTAC strategy, termed GlueTAC, for targeted membrane protein degradation with high specificity and efficiency. We first established a mass-spectrometry-based screening platform for the rapid development of a covalent nanobody (GlueBody) that allowed proximity-enabled cross-linking with surface antigens on cancer cells. By conjugation with a cell-penetrating peptide and a lysosomal-sorting sequence, the resulting GlueTAC chimera triggered the internalization and degradation of programmed death-ligand 1 (PD-L1), which provides a new avenue to target and degrade cell-surface proteins.

6.
Environ Int ; 158: 106889, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34619534

RESUMO

Eutrophication-induced water deoxygenation occurs continually in coastal oceans, and alters community structure, metabolic processes, and the energy shunt, resulting in a major threat to the ecological environment. Seasonal deoxygenation events have occurred in the Bohai Sea (China), however, how these affect the functional activity of microorganisms remains unclear. Here, through the use of absolute quantification of 16S rRNA genes amplicon sequencing and metatranscriptomics approaches, we investigated the structure of the microbial community and the patterns of transcriptional activity in deoxygenated seawaters. The dominant phyla were Proteobacteria (average value, 1.4 × 106 copies ml-1), Cyanobacteria (3.7 × 105 copies ml-1), Bacteroidetes (2.7 × 105 copies ml-1), and the ammonia-oxidizing archaea Thaumarchaeota (1.9 × 105 copies ml-1). Among the various environmental factors, dissolved oxygen, pH and temperature displayed the most significant correlation with microbial community composition and functional activity. Metatranscriptomic data showed high transcriptional activity of Thaumarchaeota in the deoxygenated waters, with a significant increase in the expression of core genes representing ammonia oxidation, ammonia transport, and carbon fixation (3-hydroxypropionic acid/4-hydroxybutyric acid cycle) pathways. The transcripts of Cyanobacteria involved in photosynthesis and carbon fixation (Calvin-Benson-Bassham cycle) significantly decreased in low oxygen waters. Meanwhile, the transcripts for the ribulose bisphosphate carboxylase-encoding gene shifted from being assigned to photoautotrophic to chemoautotrophic organisms in surface and bottom waters, respectively. Moreover, the transcription profile indicated that heterotrophs play a critical role in transforming low-molecular-weight dissolved organic nitrogen. Elevated abundances of transcripts related to microbial antioxidant activity corresponded to an enhanced aerobic metabolism of Thaumarchaeota in the low oxygen seawater. In general, our transcriptional evidences showed a population increase of Thaumarchaeota, especially the coastal ecotype of ammonia oxidizers, in low oxygen aquatic environments, and indicated an enhanced contribution of chemolithoautotrophic carbon fixation to carbon flow.

7.
Artigo em Chinês | MEDLINE | ID: mdl-34628807

RESUMO

Objective:To analyze the clinical features and the prognostic factors of early-stage external auditory canal carcinoma. Methods:Data from 36 patients with early-stage external auditory canal carcinoma(T1, T2) treated in Department of Otolaryngology, Xijing Hospital, Air Force Military Medical University from January 2008 to June 2020 were reviewed retrospectively, including clinical manifestations, surgical and treatment methods, pathological types and disease status. The relationship between survival rate and the prognostic factors was compared using Kaplan-Meier method, and the independent risk factors were analyzed by Cox proportional hazards model. Results:There were 36 patents with early-stage external auditory canal carcinoma. The common initial symptoms were otalgia(66.7%), otorrhea(41.7%) and hearing loss(30.6%). The most common histopathologic types were adenoid cystic carcinoma(50.0%) and squamous cell carcinoma(33.3%). Among the patients, 21 patients(58.3%) were initially treated, 9 patients(25.0%) were treated with salvage therapy, and 6 patients(16.7%) were re-surgery after recurrence. The 5-year disease-specific survival(DSS), disease-free survival(DFS) and relapse-free survival(RFS) were 82.3%, 64.0% and 73.0% respectively. Seven cases (19.4%) relapsed after surgery. For 5-year survival rate, the lateral temporal bone resection with superficial parotidectomy(DSS 91.7%, DFS 83.9%) is higher than the lateral temporal bone resection only(DSS 77.8%, DFS 55.6%) and sleeve resection(DSS 75.0%, DFS 56.0%), but there was no significant difference(P>0.05). In these patients, the postoperative radiotherapy and disease status had no significant impact on the survival rate. Additionally, there was no obvious correlation between recurrence and age, gender, stage, histopathologic types, operation methods and postoperative radiotherapy(P>0.05). But there were significant differences between histopathologic types and DSS or DFS(P<0.05). Multivariate regression analysis showed that histopathologic type was an independent prognostic factor for DFS. Conclusion:There are no specific clinical manifestations for early-stage external auditory canal carcinoma, such as otalgia and otorrhea. Histopathologic types have a direct impact on the patients'prognosis. Thus, individualized treatment should be applied based on pathologic findings to improve the survival rate.


Assuntos
Carcinoma de Células Escamosas , Neoplasias da Orelha , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/terapia , Meato Acústico Externo , Neoplasias da Orelha/diagnóstico , Humanos , Recidiva Local de Neoplasia , Prognóstico , Estudos Retrospectivos
8.
Small ; : e2103600, 2021 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-34643042

RESUMO

Functional nanomaterials such as iron oxide nanoparticles have been extensively explored for the diagnosis and treatment of central nervous system diseases. However, an insufficient understanding of the comprehensive nanomaterial-biological interactions in the brain hinders the nanomaterials from meeting the medical requirements for translational research. Here, FDA-approved ferumoxytol, an iron oxide nanoparticle, is chosen as the model nanomaterial for a systematic study of the dynamic interactions between ferumoxytol and immune cells, including microglia and macrophages, in the brain tumors. Strikingly, up to 90% of intratumorally injected ferumoxytol nanoparticles are recognized and phagocytized by tumor-associated microglia and macrophages. The dynamic trafficking progress of ferumoxytol in microglia and macrophages, including scavenger receptor-mediated endocytosis, lysosomal internalization, and extracellular vesicle-dominated excretion, is further studied. Importantly, the results demonstrate that extracellular vesicle-encapsulated nanoparticles could be gradually eliminated from the brain along with cerebrospinal fluid circulation over 21 days. Moreover, ferumoxytol exhibits no obvious long-term neurological toxicity after its injection. The study suggests that the dynamic biointeractions of nanoparticles with immune cells in the brain exert a key rate-limiting impact on the efficiency of targeting tumor cells and their in vivo fate and thus provide a deeper understanding of the nanomaterials in the brain for clinical applications.

9.
Accid Anal Prev ; 163: 106429, 2021 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-34638010

RESUMO

Freeway jam waves create many problems, including capacity reduction, travel delays, and safety risks. The development of cooperative vehicle infrastructure system (CVIS) has prompted numerous new strategies, which can resolve jam waves by implementing microscopic car-following control actions to individual vehicles. However, most of those strategies aimed at eliminating freeway jam waves without considering the safety risks induced by the car-following control. This paper proposes an optimal control-based vehicle speed guidance strategy to improve both traffic efficiency and safety against jam waves. The optimal controller is developed based on a discrete first-order traffic flow model formulated in Lagrangian coordinates. The optimization of vehicles' driving speed is formulated as a linear programming problem, where the constraints concerning threshold safety measures are imposed. The proposed vehicle speed guidance strategy is tested using a modified Intelligent Driving Model (IDM+), which represents real traffic dynamics in CVIS environment. The proposed speed guidance strategy is compared with a state-of-the-art jam-absorption driving strategy, which also aimed to eliminate freeway jam waves. Simulation results show that the proposed strategy outperforms that strategy in terms of both total time spent saving and surrogate safety measures' reduction. The time exposed time-to-collision (TET) is reduced by 31%, and the time integrated time-to-collision (TIT) is reduced by 9.5% on average. Furthermore, the computation time of the linear optimization is only a few seconds, which is fast enough for the online application of the proposed strategy.

11.
Sci Rep ; 11(1): 19059, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34561545

RESUMO

Tumor multifocality and location are prognostic factors for upper tract urothelial carcinoma (UTUC). However, confounding effects can appear when these two factors are analyzed together. Therefore, we aimed to investigate the impact of tumor distribution on the outcomes of multifocal UTUC after radical nephroureterectomy. From the 2780 UTUC patients in the Taiwan UTUC Collaboration Group, 685 UTUC cases with multifocal tumors (defined as more than one tumor lesion in unilateral upper urinary tract) were retrospectively included and divided into three groups: multiple renal pelvic tumors, multiple ureteral tumors, and synchronous renal pelvic and ureteral tumors included 164, 152, and 369 patients, respectively. We found the prevalence of carcinoma in situ was the highest in the synchronous group. In multivariate survival analyses, tumor distribution showed no difference in cancer-specific and disease-free survival, but there was a significant difference in bladder recurrence-free survival. The synchronous group had the highest bladder recurrence rate. In summary, tumor distribution did not influence the cancer-specific outcomes of multifocal UTUC, but synchronous lesions led to a higher rate of bladder recurrence than multiple renal pelvic tumors. We believe that the distribution of tumors reflects the degree of malignant involvement within the urinary tract, but has little significance for survival or disease progression.

12.
Eur J Neurosci ; 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34479401

RESUMO

Freezing of gait (FOG) is a common and complex manifestation of Parkinson's disease (PD) and is associated with impairment of attention. The purpose of this study was to evaluate the functional network connectivity (FNc) changes between the dorsal attention network (DAN) and the other seven intrinsic networks relevant to attention, visual-spatial, executive and motor functions in PD with or without FOG. Forty-three idiopathic PD patients (21 with FOG [FOG+] versus 22 without FOG [FOG-]) and 18 healthy controls (HC) were recruited in this study. The data-driven independent component analysis (ICA) method was used to extract and analyze the above-mentioned resting-state networks (RSNs). Compared with FOG-, FOG+ displayed decreased positive connectivity between the DAN and medial visual network (mVN) and sensory-motor network (SMN) and increased negative connectivity between the DAN and default mode network (DMN). The within-network connectivity in the SMN and visual networks were decreased, whereas the connectivity within DMN was increased significantly in FOG+. Correlation analysis showed that the clock drawing test (CDT) scores were positively correlated with the functional connectivity of mVN (r = 0.573, p = 0.008) and lateral visual network (lVN) (r = 0.510, p = 0.022), the Timed Up and Go Test (TUG) duration were negatively correlated with the connectivity of SMN (r = -0.629, p = 0.003), and the Frontal Assessment Battery (FAB) scores were negatively correlated with the connectivity of DMN in FOG+. Functional connectivity was changed in multiple intra-networks in patients with FOG. Inordinate inter-network connectivity between the DAN and other intrinsic networks may partly contribute to the mechanism of freezing.

13.
J Med Chem ; 64(18): 13719-13735, 2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34515481

RESUMO

Mitogen-activated protein kinase-interacting kinases (MNKs) and provirus integration in maloney murine leukemia virus kinases (PIMs) are downstream enzymes of cell proliferation signaling pathways associated with the resistance of tyrosine kinase inhibitors. MNKs and PIMs have complementary effects to regulate cap-dependent translation of oncoproteins. Dual inhibitors of MNKs and PIMs have not been developed. We developed a novel 4,6-disubstituted pyrido[3,2-d]pyrimidine compound 21o with selective inhibition of MNKs and PIMs. The IC50's of 21o to inhibit MNK1 and MNK2 are 1 and 7 nM and those to inhibit PIM1, PIM2, and PIM3 are 43, 232, and 774 nM, respectively. 21o inhibits the growth of myeloid leukemia K562 and MOLM-13 cells with GI50's of 2.1 and 1.2 µM, respectively. 21o decreases the levels of p-eIF4E and p-4EBP1, the downstream products of MNKs and PIMs, as well as cap-dependent proteins c-myc, cyclin D1, and Mcl-1. 21o inhibits the growth of MOLM-13 cell xenografts without causing evident toxicity. 21o represents an innovative dual MNK/PIM inhibitor with a good pharmacokinetic profile.

14.
Toxicology ; 462: 152962, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34560123

RESUMO

Inorganic arsenic is widely present in the environment. Exposure to moderate to high concentrations of arsenic from drinking water or air can cause various cancers and multisystem dysfunction. Glucose-regulated protein 78 (GRP78) is an endoplasmic reticulum (ER) stress sensor of unfolded protein response (UPR) under stress conditions and it enhances cell survival. The aim of this study is to investigate molecular mechanisms of arsenic-induced GRP78 expression in BEAS-2B cells model. We found that GRP78 protein expression was enhanced, while the level of GRP78 mRNA expression did not change under arsenic trioxide (As2O3)-induced ER stress condition in BEAS-2B cells. Cycloheximide, a protein synthesis inhibitor, completely inhibited As2O3-induced GRP78 protein expression. GRP78 mRNA expression was inhibited by actinomycin-D (Act-D). However, GRP78 protein expression was upregulated in the presence of Act-D under As2O3-induced ER stress condition. These data indicated that the upregulation of GRP78 protein under As2O3-induced UPR condition was possibly due to the increased biosynthesis of GRP78 protein. Moreover, both inositol-requiring enzyme 1α (IRE1α) RNase and kinase inhibitor KIRA6 and IRE1α kinase inhibitor APY29 completely inhibited As2O3-induced GRP78 protein expression and phosphorylation of JNK, ERK and p38 MAPK. Activation of apoptotic signaling kinase 1 (ASK1) is a downstream effector of IRE1α kinase. ASK1 inhibitor selonsertib and p38 MAPK inhibitor SB203580 partially inhibited As2O3-induced GRP78 protein expression, respectively. Our results suggested that As2O3 enhanced GRP78 protein expression in BEAS-2B cells via IRE1α kinase/ASK1/p38 MAPK signaling pathway. To our knowledge, this is the first report on illuminating the related mechanisms of increased GRP78 protein expression in As2O3-induced ER stress condition through a novel IRE1α pathway.

15.
Artigo em Inglês | MEDLINE | ID: mdl-34473888

RESUMO

In this study, we successfully solve polymorphs A and B of zeolite EMM-17, which can only crystallize in sub-micrometer-sized crystals while containing complex stacking disorders, from the three-dimensional (3D) electron diffraction (ED) data. This is the first time that the atomic structure of this polymorph has been ab initio solved, and the result reveals a unique 10(12)×10(12)×11-ring channel system. Moreover, we acquire the first atomic-resolution images of EMM-17 using integrated differential phase-contrast scanning transmission electron microscopy. The images allow us to directly observe polymorphs B and C and discover a large number of local structural defects. Based on structural features unraveled from the reciprocal-space 3D ED data and real-space images, we propose a series of energetically feasible local structures in EMM-17. We also demonstrate that the unique porous structure of EMM-17 enables efficient kinetic separation of C6 alkane isomers.

16.
BMC Endocr Disord ; 21(1): 184, 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34517857

RESUMO

BACKGROUND: There is no clear conclusion on the relationship between thyroid disease and obesity and lifestyle factors such as smoking and drinking. In this study, we analysed the association of body mass index (BMI), smoking and drinking with subclinical hypothyroidism (SHO) and thyroid nodules (TNs) with the results of a cross-sectional survey of urban residents in central China and discussed the potential mechanism linking these predictive factors and the two diseases. METHODS: This study included 1279 participants who were recruited from a Chinese community in 2011 and 2012. A questionnaire, laboratory examination and ultrasound diagnosis were conducted on these participants. Binary logistic regression analysis was used to analyse these factors. RESULTS: Overweight (BMI ≥ 25 kg/m2) was closely related to SHO and TNs in univariate and multivariate logistic regression analyses. Smoking had a protective effect on SHO and TNs, while drinking had a protective effect on TNs in univariate logistic regression and multivariate logistic regression with some covariates, but there was no significant difference between smoking and drinking and the two kinds of thyroid diseases in multivariate logistic regression analysis with all the covariates. In subgroup analysis, BMI ≥ 25 kg/m2 was significantly associated with SHO in people with positive thyroid antibodies (odds ratio (OR) = 2.221, 95 % confidence interval (CI): 1.168-4.184, P = 0.015) and smokers (OR = 2.179, 95 % CI: 1.041-4.561, P = 0.039). BMI ≥ 25 kg/m2 was significantly associated with TNs in people over 60 years old (OR = 2.069, 95 % CI: 1.149-3.724, P = 0.015) and drinkers (OR = 3.065, 95 % CI: 1.413-6.648, P = 0.005). Drinking alcohol had a protective effect on TNs in smokers (OR = 0.456, 95 % CI: 0.240-0.865, P = 0.016) and people with BMI ≥ 25 kg/m2 (OR = 0.467, 95 % CI: 0.236-0.925, P = 0.029). No significant association was found between smoking and the two thyroid diseases in different subgroups. CONCLUSIONS: Obesity is a risk factor for both TNs and SHO, especially in elderly individuals and people with positive thyroid autoantibodies. Obesity and metabolic syndrome may be more associated with TNs than SHO. Smoking may have a protective effect on thyroid disease, while drinking may have a protective effect only on TNs.

17.
Chempluschem ; 2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34533897

RESUMO

Electrocatalysts in room-temperature sodium-sulfur (RT-Na/S) have captured numerous attention. But, they suffered from shuttle effect and surface passivation. RT-Na/S show inferior energy-storage abilities, ascribed to the larger radii of Na-ions. Herein, the vigorous review is displayed from different kinds of metal-based traits, containing single metal, metal-based samples, and multifunctional hybrids. Through the controlling of structures and composition, the conversion reaction about liquid/solid phases would be enhanced, accompanied by the enhancements of cycling stabilities and rate properties, which enables the break-through of practical applications. The in-depth influences of catalytic effects on the Na-S reaction mechanism and the corresponding electrochemical performance in recently representative works are systematically reviewed. Particularly, this review is anticipated to propose potential research directions for further enhancement of RT-Na/S batteries.

18.
Nat Commun ; 12(1): 5626, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34561444

RESUMO

Transition metal-catalyzed asymmetric allylic substitution with a suitably pre-stored leaving group in the substrate is widely used in organic synthesis. In contrast, the enantioselective allylic C(sp3)-H functionalization is more straightforward but far less explored. Here we report a catalytic protocol for the long-standing challenging enantioselective allylic C(sp3)-H functionalization. Through palladium hydride-catalyzed chain-walking and allylic substitution, allylic C-H functionalization of a wide range of acyclic nonconjugated dienes is achieved in high yields (up to 93% yield), high enantioselectivities (up to 98:2 er), and with 100% atom efficiency. Exploring the reactivity of substrates with varying pKa values uncovers a reasonable scope of nucleophiles and potential factors controlling the reaction. A set of efficient downstream transformations to enantiopure skeletons showcase the practical value of the methodology. Mechanistic experiments corroborate the PdH-catalyzed asymmetric migratory allylic substitution process.

19.
J Colloid Interface Sci ; 607(Pt 1): 900-911, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34560389

RESUMO

HYPOTHESIS: A conducting droplet suspended in an insulating continuous phase, e.g. an aqueous electrolyte in an oil, is deformed by an applied electric field to nonspherical equilibrium shapes, and can even break-up under strong fields. Many technologies use electro-deformation to manipulate fluid dispersions, with surfactants present on the droplet interfaces forming stabilizing monolayers. While surfactants lower the interface tension which facilitates electro-deformation, the monolayer elasticity resists deformation. High molecular weight surfactants, with large dilatational viscosities, can potentially retard the deformation dynamics. NUMERICS: A boundary integral method simulates the dynamic interfacial deformation of a perfectly conducting droplet in a dielectric in a uniform field. The interface contains an insoluble monolayer which is a Newtonian fluid with constant dilatational viscosity obeying a Langmuir state equation. A range of initial surfactant surface concentrations are studied, with elasticity proportional to concentration. FINDINGS: Equilibrium drop deformations, unaffected by surface viscosity, are strongly resisted by elasticity at high surface concentrations, and field strengths necessary for break-up increase with elasticity. Dilatational viscosity scales with the ratio, κ∗, the surface viscosity (divided by the droplet radius) to the bulk viscosity, and can extend the deformation time. Extended times are described by a time rescaling proportional to κ∗.

20.
Stem Cell Res ; 56: 102530, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34507144

RESUMO

LAMIN A/C, encoded by the LMNA gene, supports the normal structure of the cell nucleus and regulates the connection between the nucleus and the cytoskeleton as a component of the nucleus envelope. The loss of expression and function of the LMNA gene would lead to the occurrence of congenital muscular dystrophy and Emery-Dreifuss muscular dystrophy which are collectively named as laminopathies. Here, we report a human induced pluripotent stem cell (iPSC) line (EHTJUi005-A-3) generated from a wild iPSC (EHTJUi005-A) with homozygous knockout of the gene LMNA through CRISPR/Cas9. This iPSC line provides a useful research model for studying laminopathies disease.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...