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1.
Front Neurol ; 15: 1360511, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38715691

RESUMO

Background: Cerebral vasospasm (CV) is a common complication of aneurysmal subarachnoid hemorrhage (aSAH), leading to increased morbidity and mortality rates. Endovascular therapy, particularly intra-arterial vasodilator infusion (IAVI), has emerged as a potential alternative treatment for CV. Methods: A systematic review and meta-analysis were conducted to compare the efficacy of endovascular therapy with standard treatment in patients with CV following aSAH. The primary outcomes assessed were in-hospital mortality, discharge favorable outcome, and follow-up favorable outcome. Secondary outcomes included major infarction on CT, ICU stay duration, and total hospital stay. Results: Regarding our primary outcomes of interest, patients undergoing intervention exhibited a significantly lower in-hospital mortality compared to the standard treatment group, with the intervention group having only half the mortality risk (RR = 0.49, 95% CI [0.29, 0.83], p = 0.008). However, there were no significant differences between the two groups in terms of discharge favorable outcome (RR = 0.99, 95% CI [0.68, 1.45], p = 0.963) and follow-up favorable outcome (RR = 1.09, 95% CI [0.86, 1.39], p = 0.485). Additionally, there was no significant difference in major infarction rates (RR = 0.79, 95% CI [0.34, 1.84], p = 0.588). It is important to note that patients undergoing endovascular treatment experienced longer stays in the ICU (MD = 6.07, 95% CI [1.03, 11.12], p = 0.018) and extended hospitalization (MD = 5.6, 95% CI [3.63, 7.56], p < 0.001). Subgroup analyses based on the mode of endovascular treatment further supported the benefits of IAVI in lowering in-hospital mortality (RR = 0.5, 95% CI [0.27, 0.91], p = 0.023). Conclusion: Endovascular therapy, particularly IAVI, holds promising potential in reducing in-hospital mortality for patients with CV following aSAH. However, it did not show significant improvement in long-term prognosis and functional recovery. Further research with larger sample sizes and randomized controlled trials is necessary to validate these findings and optimize the treatment strategy for cerebral vasospasm in aSAH patients. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42023451741.

2.
Small ; : e2401815, 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38573922

RESUMO

Currently, research on thermal interface materials (TIMs) is primarily focused on enhancing thermal conductivity. However, strong adhesion and multifunctionality are also important characteristics for TIMs when pursing more stable interface heat conduction. Herein, a novel poly(urethane-urea-imide) (PUUI) elastomer containing abundant dynamic hydrogen bonds network and reversible disulfide linkages is successfully synthesized for application as a TIM matrix. The PUUI can self-adapt to the metal substrate surface at moderate temperatures (80 °C) and demonstrates a high adhesion strength of up to 7.39 MPa on aluminum substrates attributed its noncovalent interactions and strong intrinsic cohesion. Additionally, the PUUI displays efficient self-healing capability, which can restore 94% of its original mechanical properties after self-healing for 6 h at room temperature. Furthermore, PUUI composited with aluminum nitride and liquid metal hybrid fillers demonstrates a high thermal conductivity of 3.87 W m-1 K-1 while maintaining remarkable self-healing capability and adhesion. When used as an adhesive-type TIM, it achieves a low thermal contact resistance of 22.1 mm2 K W-1 at zero pressure, only 16.7% of that of commercial thermal pads. This study is expected to break the current research paradigm of TIMs and offers new insights for the development of advanced, reliable, and sustainable TIMs.

3.
J Am Chem Soc ; 146(18): 12712-12722, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38655573

RESUMO

Persistent chiral organic open-shell systems have captured growing interest due to their potential applications in organic spintronic and optoelectronic devices. Nevertheless, the integration of configurationally stable chirality into an organic open-shell system continues to pose challenges in molecular design. The π-extended skeleton incorporated in spiro-conjugated carbocycles can provide robust chiroptical properties and a significant stabilization of the excited and ionic radical states. However, this approach has been relatively less explored in the design of persistent organic open-shell systems. We report here the (S,S)-, (R,R)-, and meso-isomers of doubly spiro-conjugated carbocycles featuring flat and rigid carbon-bridged para-phenylenevinylene (CPV) of different conjugation lengths connected by two spiro-carbon centers, which we denote D-spiro-CPV for its quasi-dimeric structure. Our synthetic method based on a double lithiation cyclization approach enables facile production of D-spiro-CPV. D-spiro-CPVs exhibit circularly polarized luminescence (CPL) with high fluorescence quantum yields (ΦFL) resulting in a high CPL brightness of 21 M-1 cm-1 and also exhibit high thermal and photostability. The monoradical cation of D-spiro-CPV absorbing near-infrared light is notably persistent, exhibiting a half-life of 570 h under ambient conditions due to doubly spiro-conjugative stabilization. Theoretical and electrochemical studies indicate the radical cation of D-spiro-CPVs presents a non-Aufbau electron filling, exhibiting inversion of the energy level of the singly occupied molecular orbital (SOMO) and the highest (doubly) occupied molecular orbitals with the SOMO level even below the HOMO-1 level (double SHI effect). Our discoveries provide valuable insights into non-Aufbau molecules and the development of configurationally stable, optically active persistent radicals.

4.
Dalton Trans ; 53(12): 5624-5631, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38440932

RESUMO

Noble metal nanomaterials have been widely demonstrated to possess intrinsic enzyme-like properties and have been increasingly applied in the fields of analysis and biomedicine. However, current exploration of high-activity noble metal nanozymes is still far from adequate. The construction of hollow structures and adjustment of their elemental composition are effective ways to improve the specific activity (SA) of nanozymes. In this study, trimetallic PtPdAu hollow nanorods (HNRs) were developed using a galvanic replacement reaction and Kirkendall effect. The catalytic experiment showed that the PtPdAu HNRs possessed outstanding peroxidase-like performance and their SA value was up to 563.71 U mg-1, which is remarkable among various previously reported nanozymes and higher than that of monometallic or bimetallic counterparts with similar structure and size prepared in this study. Electron paramagnetic resonance (EPR)measurements showed that the PtPdAu HNRs could contribute to the formation of hydroxyl radicals (˙OH) in catalyzing hydrogen peroxide. When using PtPdAu HNRs as a nanozyme in the colorimetric detection of H2O2 and ascorbic acid (AA), the limits of detection were as low as 1.8 µM and 0.068 µM, respectively. This study demonstrates that PtPdAu HNRs are high-activity nanozymes and have the potential to be applied in the field of analysis.


Assuntos
Nanotubos , Peroxidase , Peroxidase/química , Colorimetria , Peróxido de Hidrogênio/química , Peroxidases/química , Corantes/química
5.
Nutr Cancer ; 76(5): 452-462, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38494910

RESUMO

Abnormal activation of the Wnt/ß-catenin signaling pathway is a driving force behind the progression of gastric cancer. Atovaquone, known as an antimalarial drug, has emerged as a potential candidate for anti-cancer therapy. This study investigated atovaquone's effects on gastric cancer and its underlying mechanisms. Using gastric cancer cell lines, we found that atovaquone, at concentrations relevant to clinical use, significantly reduced their viability. Notably, atovaquone exhibited a lower effectiveness in reducing the viability of normal gastric cells compared to gastric cancer cells. We further demonstrated that atovaquone inhibited gastric cancer growth and colony formation. Mechanism studies revealed that atovaquone inhibited mitochondrial respiration and induced oxidative stress. Experiments using ρ0 cells, deficient in mitochondrial respiration, indicated a slightly weaker effect of atovaquone on inducing apoptosis compared to wildtype cells. Atovaquone increased phosphorylated ß-catenin at Ser45 and Ser33/37/Thr41, elevated Axin, and reduced ß-catenin. The inhibitory effects of atovaquone on ß-catenin were reversed upon depletion of CK1α. Furthermore, the combination of atovaquone with paclitaxel suppressed gastric cancer growth and improved overall survival in mice. Given that atovaquone is already approved for clinical use, these findings suggest its potential as a valuable addition to the drug arsenal available for treating gastric cancer.


Assuntos
Neoplasias Gástricas , Via de Sinalização Wnt , Animais , Camundongos , Atovaquona/farmacologia , Atovaquona/uso terapêutico , beta Catenina/metabolismo , Neoplasias Gástricas/tratamento farmacológico , Linhagem Celular Tumoral , Caseína Quinases/metabolismo , Proliferação de Células
6.
Adv Mater ; 36(19): e2313099, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38299926

RESUMO

Metal halide perovskite solar cells (PSCs) show significant advancements in power conversion efficiency (PCE). However, the open-circuit voltage (VOC) of PSCs is limited by interfacial factors such as defect-induced recombination, energy band mismatch, and non-intimate interface contact. Here, an exciplex interface is first developed based on the strategically designed and synthesized two spirobifluorene phosphonate molecules to mitigate VOC loss in PSCs. The exciplex interface constructed by the intimate contact between the multi-functional molecules and hole transport layer takes the roles to promote the hole extraction by donor-acceptor interaction, passivate coordination-unsaturated Pb2+ defects by equipped phosphonate groups, and optimize the energy level alignment. As a result, a record VOC of 1.26 V with a perovskite bandgap of 1.61 eV is achieved, representing over 95% of theoretical limit. This advancement leads to an increase in PCE from 21.29% to 24.12% and improved stability. The exciplex interface paves the way for addressing the long-standing challenge of VOC loss and promotes the wider application of PSCs.

7.
Physiol Int ; 111(1): 35-46, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38261006

RESUMO

Objective: Gastric cancer is the most frequent gastrointestinal malignancy with a poor prognosis. Rac GTPase activation protein 1 (RACGAP1) is a novel tumor promotor, whose detailed effect on gastric cancer remains to be further elucidated. Hence, this study identifies the action of RACGAP1 on gastric cancer and investigates the potential mechanism. Methods: RACGAP1 expression in gastric cancer was analyzed based on the data of The Cancer Genome Atlas (TCGA) database. Cell proliferation was measured by CCK-8 and colony formation assay. Cell migration and invasion were evaluated by transwell assay. Cell apoptosis was assessed by flow cytometry. Cell autophagy was evaluated via determining LC3. Results: RACGAP1 presented at high level in gastric cancer cells. Overexpressed RACGAP1 potentiated gastric cancer cell proliferation, migration, and invasion. Besides, silenced RACGAP1 induced cell apoptosis and autophagy. Furthermore, RACGAP1 suppressed the expression of SIRT1 and Mfn2. Conclusion: RACGAP1 was overexpressed in gastric cancer. RACGAP1 potentiated aggressive behaviors of gastric cancer, and suppressed cell apoptosis and autophagy via modulating SIRT1/Mfn2. RACGAP1 may be a valuable target in the treatment of gastric cancer.


Assuntos
Neoplasias Gástricas , Humanos , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Proteínas Ativadoras de GTPase/genética , Proteínas Ativadoras de GTPase/metabolismo , Sirtuína 1/genética , Proliferação de Células , Autofagia , Linhagem Celular Tumoral
8.
Nat Commun ; 15(1): 419, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38199996

RESUMO

Bioisosteric design has become an essential approach in the development of drug molecules. Recent advancements in synthetic methodologies have enabled the rapid adoption of this strategy into drug discovery programs. Consequently, conceptionally innovative practices would be appreciated by the medicinal chemistry community. Here we report an expeditous synthetic method for synthesizing aryl difluoromethyl bicyclopentane (ADB) as a bioisostere of the benzophenone core. This approach involves the merger of light-driven C-F bond activation and strain-release chemistry under the catalysis of a newly designed N-anionic-based organic photocatalyst. This defluorinative coupling methodology enables the direct conversion of a wide variety of commercially available trifluoromethylaromatic C-F bonds (more than 70 examples) into the corresponding difluoromethyl bicyclo[1.1.1]pentanes (BCP) arenes/difluoromethyl BCP boronates in a single step. The strategy can also be applied to [3.1.1]and [4.1.1]propellane systems, providing access to analogues with different geometries. Moreover, we have successfully used this protocol to rapidly prepare ADB-substituted analogues of the bioactive molecule Adiporon. Biological testing has shown that the ADB scaffold has the potential to enhance the pharmacological properties of benzophenone-type drug candidates.

9.
Chin J Integr Med ; 30(1): 25-33, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37750986

RESUMO

OBJECTIVE: To determine whether monotropein has an anticancer effect and explore its potential mechanisms against colorectal cancer (CRC) through network pharmacology and molecular docking combined with experimental verification. METHODS: Network pharmacology and molecular docking were used to predict potential targets of monotropein against CRC. Cell counting kit assay, plate monoclonal assay and microscopic observation were used to investigate the antiproliferative effects of monotropein on CRC cells HCT116, HT29 and LoVo. Flow cytometry and scratch assay were used to analyze apoptosis and cell cycle, as well as cell migration, respectively in HCT116, HT29, and LoVo cells. Western blotting was used to detect the expression of proteins related to apoptosis, cell cycle, and cell migration, and the expression of proteins key to the Akt pathway. RESULTS: The Gene Ontology and Reactome enrichment analyses indicated that the anticancer potential of monotropein against CRC might be involved in multiple cancer-related signaling pathways. Among these pathways, RAC-beta serine/threonine-protein kinase (Akt1, Akt2), cyclin-dependent kinase 6 (CDK6), matrix metalloproteinase-9 (MMP9), epidermal growth factor receptor (EGFR), cell division control protein 42 homolog (CDC42) were shown as the potential anticancer targets of monotropein against CRC. Molecular docking suggested that monotropein may interact with the 6 targets (Akt1, Akt2, CDK6, MMP9, EGFR, CDC42). Subsequently, cell activity of HCT116, HT29 and LoVo cell lines were significantly suppressed by monotropein (P<0.05). Furthermore, our research revealed that monotropein induced cell apoptosis by inhibiting Bcl-2 and increasing Bax, induced G1-S cycle arrest in colorectal cancer by decreasing the expressions of CyclinD1, CDK4 and CDK6, inhibited cell migration by suppressing the expressions of CDC42 and MMP9 (P<0.05), and might play an anticancer role through Akt signaling pathway. CONCLUSION: Monotropein exerts its antitumor effects primarily by arresting the cell cycle, causing cell apoptosis, and inhibiting cell migration. This indicates a high potential for developing novel medication for treating CRC.


Assuntos
Neoplasias Colorretais , Proteínas Proto-Oncogênicas c-akt , Humanos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proliferação de Células , Metaloproteinase 9 da Matriz , Simulação de Acoplamento Molecular , Ciclo Celular , Receptores ErbB , Apoptose , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/patologia , Linhagem Celular Tumoral
10.
Arterioscler Thromb Vasc Biol ; 44(1): 177-191, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38150518

RESUMO

BACKGROUND: The heart relies heavily on external fatty acid (FA) for energy production. VEGFB (vascular endothelial growth factor B) has been shown to promote endothelial FA uptake by upregulating FA transporters. However, its impact on LPL (lipoprotein lipase)-mediated lipolysis of lipoproteins, a major source of FA for cardiac use, is unknown. METHODS: VEGFB transgenic (Tg) rats were generated by using the α-myosin heavy chain promoter to drive cardiomyocyte-specific overexpression. To measure coronary LPL activity, Langendorff hearts were perfused with heparin. In vivo positron emission tomography imaging with [18F]-triglyceride-fluoro-6-thia-heptadecanoic acid and [11C]-palmitate was used to determine cardiac FA uptake. Mitochondrial FA oxidation was evaluated by high-resolution respirometry. Streptozotocin was used to induce diabetes, and cardiac function was monitored using echocardiography. RESULTS: In Tg hearts, the vectorial transfer of LPL to the vascular lumen is obstructed, resulting in LPL buildup within cardiomyocytes, an effect likely due to coronary vascular development with its associated augmentation of insulin action. With insulin insufficiency following fasting, VEGFB acted unimpeded to facilitate LPL movement and increase its activity at the coronary lumen. In vivo PET imaging following fasting confirmed that VEGFB induced a greater FA uptake to the heart from circulating lipoproteins as compared with plasma-free FAs. As this was associated with augmented mitochondrial oxidation, lipid accumulation in the heart was prevented. We further examined whether this property of VEGFB on cardiac metabolism could be useful following diabetes and its associated cardiac dysfunction, with attendant loss of metabolic flexibility. In Tg hearts, diabetes inhibited myocyte VEGFB gene expression and protein secretion together with its downstream receptor signaling, effects that could explain its lack of cardioprotection. CONCLUSIONS: Our study highlights the novel role of VEGFB in LPL-derived FA supply and utilization. In diabetes, loss of VEGFB action may contribute toward metabolic inflexibility, lipotoxicity, and development of diabetic cardiomyopathy.


Assuntos
Cardiomiopatias Diabéticas , Insulina , Ratos , Animais , Insulina/farmacologia , Fator B de Crescimento do Endotélio Vascular/genética , Fator B de Crescimento do Endotélio Vascular/metabolismo , Ratos Wistar , Miócitos Cardíacos/metabolismo , Ácidos Graxos/metabolismo , Cardiomiopatias Diabéticas/genética , Cardiomiopatias Diabéticas/metabolismo , Triglicerídeos/metabolismo , Lipase Lipoproteica/metabolismo , Miocárdio/metabolismo
11.
Diabetes Metab Syndr Obes ; 16: 4025-4042, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38089431

RESUMO

Introduction: Adjusting internal organs and dredging channel electroacupuncture has a definite effect on type 2 diabetes, but the specific mechanism still needs to be further clarified. This study aims to investigate the effects of electroacupuncture on the gut microbiota and bile acids in db/db mice after the intervention of "adjusting internal organs and dredging channel" and further explore its mechanism of action in treating T2DM. Methods: We used db/db mice as the animal model and db/m mice from the same litter as the blank control group, a total of 4 weeks of intervention were conducted. We evaluated the effectiveness of the "adjusting internal organs and dredging channel" treatment by detecting indicators related to glucose and lipid- metabolism. Detect changes in the gut microbiota of mice in each group using 16SrDNA sequencing technology. The content of bile acids in mouse feces was determined using liquid chromatography mass spectrometry, and the correlation analysis between different bile acids and differential bacterial communities was performed. The expression levels of TGR5 and GLP-1 proteins were measured using the Western blot method. Results: Adjusting internal organs and dredging channel electroacupuncture can improve blood glucose levels in db/db mice, increase the abundance of Firmicutes and Actinobacteria, and increase the content of fecal bile acid pool heavy CA and UDCA. At the same time, it also increased the content of TGR5/GLP1 in the small intestine. Conclusion: Adjusting internal organs and dredging channel electroacupuncture can improve the disorder of glucose and lipid metabolism in db/db mice, regulate the abundance and colony composition of intestinal microbiota in mice, and regulate bile acid metabolism in mice. The interaction between bile acid and intestinal microbiota can also be observed; Mutual influence may play a role in regulating blood sugar together.

12.
Front Neurol ; 14: 1224425, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37670774

RESUMO

Background: Carotid cavernous fistula (CCF) refers to the abnormal arteriovenous communication between the carotid system at the skull base and the sphenoid cavernous sinus, which is caused by trauma in almost 75% of cases. The drainage of venous blood to the spinal cord represents a distinctive mechanism, which is commonly observed in dural arteriovenous fistula (DAVF), and typically manifests clinically as progressive myelopathy. However, it is a rare occurrence in clinical practice that traumatic carotid cavernous fistula (TCCF) causes delayed quadriplegia through perimedullary venous drainage. Case presentation: We report the case of a 29-year-old male patient who was admitted to the hospital with a sudden onset of headache and quadriplegia. The patient had previously lost his right eye in a traffic accident 5 years ago. Cerebral angiography showed a high-flow direct CCF on the right side, accompanied by obvious drainage of cerebellar and perimedullary veins. We successfully performed coil embolization for the CCF, and the symptoms of the patient gradually improved after the operation. During follow-up at sixth-months, the patient regained the ability to walk independently. Conclusion: We experienced a rare case of TCCF with quadriplegia. Utilizing coil embolization, we achieved successful improvement in the patient's condition. However, the mechanism and the best treatment of CCF drainage through the perimedullary vein are still unclear. We need to further explore the pathophysiological information of CCF venous drainage.

13.
Braz J Microbiol ; 54(3): 2527-2534, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37344656

RESUMO

Porcine epidemic diarrhea virus (PEDV) is a virus that can cause diarrhea in pigs, resulting in significant economic losses to the pig industry. The mutation of the virus and its co-infection with other enteroviruses leads to poor control of PEDV infection. In this study, we found that the diarrhea outbreak in a pig farm in Shandong Province was mainly caused by PEDV infection. Through high-throughput sequencing, we also detected one other diarrhea-related virus (porcine kobuvirus). In the phylogenetic analysis and molecular characterization of the detected PEDV S gene and PKV, it was found that the S gene of the PEDV strain detected in this study (named SD22-2) had more mutations than the CV777 strain. The highest homology between PKV (named SD/2022/China) detected in this study and other strains was only 89.66%. Based on polyprotein, we divided SD/2022/China strains into a new grouping (designated group 4) and detected recombination signals. In summary, SD22-2 detected in this study is a new PEDV variant strain, and SD/2022/China strain might be a novel PKV strain. We also found the co-infection of the new PEDV variant and the novel PKV isolated from piglets with diarrhea. Our data suggested the importance of continuous surveillance of PEDV and PKV.


Assuntos
Coinfecção , Infecções por Coronavirus , Kobuvirus , Vírus da Diarreia Epidêmica Suína , Doenças dos Suínos , Animais , Suínos , Filogenia , Vírus da Diarreia Epidêmica Suína/genética , Kobuvirus/genética , Infecções por Coronavirus/epidemiologia , Diarreia/epidemiologia , China/epidemiologia
14.
Braz J Microbiol ; 54(2): 1309-1314, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37036658

RESUMO

Sapporo virus (SaV) is an emerging enteric virus causing acute gastroenteritis in animals. Here, we found a novel porcine SaV (PoSaV) strain (named SD2202) from the piglets with diarrhea in China in 2022. The highest nucleotide homology of SD2202 with other PoSaV strains is only 90.67%, and there are four amino acids insertion in the viral capsid protein and minor structural protein compared to other PoSaV; furthermore, we found that SD2202 belongs to a new GIII genogroup clade (GIII-6 clade). Interestingly, we found that SD2202 may be an intra-genogroup recombinant strain. Taken together, we found a novel PoSaV implicated in the piglet diarrhea epidemic and emphasized the importance of continuous surveillance of PoSaV.


Assuntos
Infecções por Caliciviridae , Sapovirus , Doenças dos Suínos , Animais , Suínos , Sapovirus/genética , Infecções por Caliciviridae/veterinária , Filogenia , Diarreia/veterinária , China/epidemiologia , Fezes
15.
Angew Chem Int Ed Engl ; 62(13): e202218151, 2023 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-36727590

RESUMO

Lithium metal batteries hold great promise for promoting energy density and operating at low temperatures, yet they still suffer from insufficient Li compatibility and slow kinetic, especially at ultra-low temperatures. Herein, we rationally design and synthesize a new amphiphilic solvent, 1,1,2,2-tetrafluoro-3-methoxypropane, for use in battery electrolytes. The lithiophilic segment is readily to solvate Li+ to induce self-assembly of the electrolyte solution to form a peculiar core-shell-solvation structure. Such unique solvation structure not only largely improves the ionic conductivity to allow fast Li+ transport and lower the desolvation energy to enable facile desolvation, but also leads to the formation of a highly robust and conductive inorganic SEI. The resulting electrolyte demonstrates high Li efficiency and superior cycling stability from room temperature to -40 °C at high current densities. Meanwhile, anode-free high-voltage cell retains 87 % capacity after 100 cycles.

16.
J Phys Chem C Nanomater Interfaces ; 126(46): 19726-19732, 2022 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-36466036

RESUMO

Substituting heteroatoms and non-benzenoid carbons into nanographene structure offers a unique opportunity for atomic engineering of electronic properties. Here we show the bottom-up synthesis of graphene nanoribbons (GNRs) with embedded fused BN-doped rubicene components on a Au(111) surface using on-surface chemistry. Structural and electronic properties of the BN-GNRs are characterized by scanning tunneling microscopy (STM) and atomic force microscopy (AFM) with CO-terminated tips supported by numerical calculations. The periodic incorporation of BN heteroatoms in the GNR leads to an increase of the electronic band gap as compared to its undoped counterpart. This opens avenues for the rational design of semiconducting GNRs with optoelectronic properties.

17.
J Am Chem Soc ; 144(47): 21692-21701, 2022 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-36383691

RESUMO

C-H/C-H coupling via C-H activation provides straightforward synthetic access to the construction of complex π-conjugated organic molecules. The palladium-catalyzed Fujiwara-Moritani (FM) coupling between an arene and an electron-deficient olefin presents an early example but is not applicable to enamines such as N-vinylcarbazoles and N-vinylindoles. We report herein iron-catalyzed C-H/C-H heterocoupling between enamines and thiophenes and its application to copolymerization of bisenamine and bisthiophene using diethyl oxalate as an oxidant and AlMe3 as a base, as a result of our realization that synthetic limitations in oxidative C-H/C-H couplings imposed by the high redox potential of the Pd(II)/Pd(0) catalytic cycle can be circumvented by the use of iron, which has a lower Fe(III)/Fe(I) redox potential. The trisphosphine ligand provides a coordination environment for iron to achieve the reaction's regio-, stereo-, and chemoselectivity. The reaction includes C-H activation of thiophene via σ-bond metathesis and subsequent enamine C-H cleavage triggered by nucleophilic enamine addition to the Fe(III) center, thereby differing from the FM reaction in mechanism and synthetic scope. The copolymers synthesized by the new reaction possess a new type of enamine-incorporated polymer backbone.


Assuntos
Ferro , Tiofenos , Ferro/química , Catálise , Paládio/química , Polimerização
18.
J Am Heart Assoc ; 11(23): e027958, 2022 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-36416172

RESUMO

Background Lipoprotein lipase (LPL)-derived fatty acid is a major source of energy for cardiac contraction. Synthesized in cardiomyocytes, LPL requires translocation to the vascular lumen for hydrolysis of lipoprotein triglyceride, an action mediated by endothelial cell (EC) release of heparanase. We determined whether flow-mediated biophysical forces can cause ECs to secrete heparanase and thus regulate cardiac metabolism. Methods and Results Isolated hearts were retrogradely perfused. Confluent rat aortic ECs were exposed to laminar flow using an orbital shaker. Cathepsin L activity was determined using gelatin-zymography. Diabetes was induced in rats with streptozotocin. Despite the abundance of enzymatically active heparanase in the heart, it was the enzymatically inactive, latent heparanase that was exceptionally responsive to flow-induced release. EC exposed to orbital rotation exhibited a similar pattern of heparanase secretion, an effect that was reproduced by activation of the mechanosensor, Piezo1. The laminar flow-mediated release of heparanase from EC required activation of both the purinergic receptor and protein kinase D, a kinase that assists in vesicular transport of proteins. Heparanase influenced cardiac metabolism by increasing cardiomyocyte LPL displacement along with subsequent replenishment. The flow-induced heparanase secretion was augmented following diabetes and could explain the increased heparin-releasable pool of LPL at the coronary lumen in these diabetic hearts. Conclusions ECs sense fluid shear-stress and communicate this information to subjacent cardiomyocytes with the help of heparanase. This flow-induced mechanosensing and its dynamic control of cardiac metabolism to generate ATP, using LPL-derived fatty acid, is exquisitely adapted to respond to disease conditions, like diabetes.


Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus , Lipase Lipoproteica , Animais , Ratos , Diabetes Mellitus/enzimologia , Ácidos Graxos/metabolismo , Lipase Lipoproteica/metabolismo , Diabetes Mellitus Experimental/enzimologia , Estreptozocina
19.
J Am Chem Soc ; 144(46): 21146-21156, 2022 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-36346318

RESUMO

As a crystal approaches a few nanometers in size, atoms become nonequivalent, bonds vibrate, and quantum effects emerge. To study quantum dots (QDs) with structural control common in molecular science, we need atomic precision synthesis and analysis. We describe here the synthesis of lead bromide perovskite magic-sized nanoclusters via self-organization of a lead malate chelate complex and PbBr3- under ambient conditions. Millisecond and angstrom resolution electron microscopic analysis revealed the structure and the dynamic behavior of individual QDs─structurally uniform cubes made of 64 lead atoms, where eight malate molecules are located on the eight corners of the cubes, and oleylammonium cations lipophilize and stabilize the edges and faces. Lacking translational symmetry, the cube is to be viewed as a molecule rather than a nanocrystal. The QD exhibits quantitative photoluminescence and stable electroluminescence at ≈460 nm with a narrow half-maximum linewidth below 15 nm, reflecting minimum structural defects. This controlled synthesis and precise analysis demonstrate the potential of cinematic chemistry for the characterization of nanomaterials beyond the conventional limit.


Assuntos
Nanopartículas , Nanoestruturas , Pontos Quânticos , Pontos Quânticos/química , Malatos
20.
Mol Biol Evol ; 39(7)2022 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-35687719

RESUMO

Due to extensive pleiotropy, trans-acting elements are often thought to be evolutionarily constrained. While the impact of trans-acting elements on gene expression evolution has been extensively studied, relatively little is understood about the contribution of a single trans regulator to interspecific expression and phenotypic divergence. Here, we disentangle the effects of genomic context and miR-983, an adaptively evolving young microRNA, on expression divergence between Drosophila melanogaster and D. simulans. We show miR-983 effects promote interspecific expression divergence in testis despite its antagonism with the often-predominant context effects. Single-cyst RNA-seq reveals that distinct sets of genes gain and lose miR-983 influence under disruptive or diversifying selection at different stages of spermatogenesis, potentially helping minimize antagonistic pleiotropy. At the round spermatid stage, the effects of miR-983 are weak and distributed, coincident with the transcriptome undergoing drastic expression changes. Knocking out miR-983 causes reduced sperm length with increased within-individual variation in D. melanogaster but not in D. simulans, and the D. melanogaster knockout also exhibits compromised sperm defense ability. Our results provide empirical evidence for the resolution of antagonistic pleiotropy and also have broad implications for the function and evolution of new trans regulators.


Assuntos
Drosophila , MicroRNAs , Animais , Drosophila/genética , Drosophila melanogaster/genética , Masculino , MicroRNAs/genética , Sêmen , Especificidade da Espécie , Espermatogênese/genética
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