Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 108
Filtrar
1.
Org Lett ; 2024 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-39360860

RESUMO

Actin stabilizers that are capable of interfering with actin cytoskeleton dynamics play an important role in chemical biology. Rhizopodin, a novel actin stabilizer, affects the actin cytoskeleton at nanomolar concentrations and exhibits potent antiproliferative activities against a range of tumor cell lines with IC50 values in the low nanomolar range. Herein, we report the total synthesis of rhizopodin based on a late-stage oxazole ring formation strategy, whose success demonstrates the feasibility of late-stage oxazole ring formation in the synthesis of complex oxazole containing natural products. Other features of the synthesis include a Nagao aldol reaction, a Suzuki coupling, a Yamaguchi esterification, a modified Robinson-Gabriel synthesis of the oxazoles, and a bidirectional Ba(OH)2-mediated Horner-Wadsworth-Emmons (HWE) reaction.

2.
Angew Chem Int Ed Engl ; : e202416319, 2024 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-39284773

RESUMO

Despite extensive studies has been explored on single-molecule switches and rectifiers, the design of single-molecule inductors has not been explored due to the experimental challenges in the investigation of frequency-dependent charge transport at the single-molecule scale. In this study, we synthesized a helicene-based helical molecular wire and carried out meticulous single-molecule conductance measurements, combined with current-voltage (IV) studies with varying frequencies using the scanning tunneling microscope break junction (STM-BJ) technique. Our results reveal the formation of a single-molecule junction and highlight the unique behavior of the molecular wire in response to different alternating current (AC) varying frequencies. The transport of charges occurs selectively either through the coiled backbone of the conjugated helical structure or vertically via π-π stacking, depending on the frequency of the applied AC. Notably, our investigation demonstrates the functionality of the wire as an inductor at low frequencies, and a capacitor at high frequencies. This work lays the foundation for a systematic approach to designing, fabricating, and implementing single-molecule logic devices such as inductors and wave filters.

3.
Signal Transduct Target Ther ; 9(1): 230, 2024 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-39237509

RESUMO

Cardiac biological pacing (BP) is one of the future directions for bradyarrhythmias intervention. Currently, cardiac pacemaker cells (PCs) used for cardiac BP are mainly derived from pluripotent stem cells (PSCs). However, the production of high-quality cardiac PCs from PSCs remains a challenge. Here, we developed a cardiac PC differentiation strategy by adopting dual PC markers and simulating the developmental route of PCs. First, two PC markers, Shox2 and Hcn4, were selected to establish Shox2:EGFP; Hcn4:mCherry mouse PSC reporter line. Then, by stepwise guiding naïve PSCs to cardiac PCs following naïve to formative pluripotency transition and manipulating signaling pathways during cardiac PCs differentiation, we designed the FSK method that increased the yield of SHOX2+; HCN4+ cells with typical PC characteristics, which was 12 and 42 folds higher than that of the embryoid body (EB) and the monolayer M10 methods respectively. In addition, the in vitro cardiac PCs differentiation trajectory was mapped by single-cell RNA sequencing (scRNA-seq), which resembled in vivo PCs development, and ZFP503 was verified as a key regulator of cardiac PCs differentiation. These PSC-derived cardiac PCs have the potential to drive advances in cardiac BP technology, help with the understanding of PCs (patho)physiology, and benefit drug discovery for PC-related diseases as well.


Assuntos
Diferenciação Celular , Miócitos Cardíacos , Células-Tronco Pluripotentes , Animais , Camundongos , Diferenciação Celular/genética , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/citologia , Células-Tronco Pluripotentes/metabolismo , Células-Tronco Pluripotentes/citologia , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/genética , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/metabolismo , Corpos Embrioides/citologia , Corpos Embrioides/metabolismo
4.
Adv Mater ; : e2406456, 2024 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-39295460

RESUMO

Here, a unique crossbar architecture is designed and fabricated, incorporating vertically integrated self-assembled monolayers in electronic devices. This architecture is used to showcase 100 individual vertical molecular junctions on a single chip with a high yield of working junctions and high device uniformity. The study introduces a transfer approach for patterned liquid-metal eutectic alloy of gallium and indium top electrodes, enabling the creation of fully flexible molecular devices with electrical functionalities. The devices exhibit excellent charge transport performance, sustain a high rectification ratio (>103), and stable endurance and retention properties, even when the devices are significantly bent. Furthermore, Boolean logic gates, including OR and AND gates, as well as half-wave and full-wave rectifying circuits, are successfully implemented. The unique design of the flexible molecular device represents a significant step in harnessing the potential of molecular devices for high-density integration and possible molecule-based computing.

5.
Cell Death Dis ; 15(9): 710, 2024 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-39349437

RESUMO

The spalt (Sal) gene family has four members (Sall1-4) in vertebrates, all of which play pivotal roles in various biological processes and diseases. However, the expression and function of SALL2 in development are still less clear. Here, we first charted SALL2 protein expression pattern during mouse embryo development by immunofluorescence, which revealed its dominant expression in the developing nervous system. With the establishment of Sall2 deficient mouse embryonic stem cells (ESCs), the in vitro neural differentiation system was leveraged to interrogate the function of SALL2, which showed impaired neural differentiation of Sall2 knockout (KO) ESCs. Furthermore, neural stem cells (NSCs) could not be derived from Sall2 KO ESCs and the generation of neural tube organoids (NTOs) was greatly inhibited in the absence of SALL2. Meanwhile, transgenic expression of E1 isoform of SALL2 restored the defects of neural differentiation in Sall2 KO ESCs. By chromatin immunoprecipitation sequencing (ChIP-seq), Tuba1a was identified as downstream target of SALL2, whose function in neural differentiation was confirmed by rescuing neural phenotypes of Sall2 KO ESCs when overexpressed. In sum, by elucidating SALL2 expression dynamics during early mouse development and mechanistically characterizing its indispensable role in neural differentiation, this study offers insights into SALL2's function in human nervous system development, associated pathologies stemming from its mutations and relevant therapeutic strategy.


Assuntos
Diferenciação Celular , Células-Tronco Embrionárias Murinas , Fatores de Transcrição , Animais , Camundongos , Células-Tronco Embrionárias Murinas/metabolismo , Células-Tronco Embrionárias Murinas/citologia , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Células-Tronco Neurais/metabolismo , Células-Tronco Neurais/citologia , Neurogênese , Camundongos Knockout , Regulação da Expressão Gênica no Desenvolvimento
6.
Molecules ; 29(15)2024 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-39125004

RESUMO

The absolute stereochemical configurations of acremolides A and B were predicted by a biochemistry-based rule and unambiguously confirmed through their total syntheses. The features of the total syntheses include sequential Krische's Ir-catalyzed crotylation, Brown's borane-mediated crotylation, Mitsunobu esterification reaction, and cross-metathesis reaction. The efficient total synthesis enabled clear validation of the predicted stereochemistry for acremolides A and B.

7.
Chem Sci ; 15(33): 13486-13494, 2024 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-39183916

RESUMO

Nucleophilic substitution is one of the most fundamental chemical reactions, and the pursuit of high reaction rates of the reaction is one of the ultimate goals in catalytic and organic chemistry. The reaction barrier of the nucleophilic substitution originates from the highly polar nature of the transition state that can be stabilized under the electric field created by the solvent environment. However, the intensity of the induced solvent-electric field is relatively small due to the random orientation of solvent molecules, which hinders the catalytic effects and restricts the reaction rates. This work shows that oriented external electric fields applied within a confined nanogap between two nanoscopic tips could accelerate the Menshutkin reaction by more than four orders of magnitude (over 39 000 times). The theoretical calculations reveal that the electric field inside the nanogap reduces the energy barrier to increase the reaction rate. Our work suggests the great potential of electrostatic catalysis for green synthesis in the future.

8.
Am J Transl Res ; 16(6): 2453-2463, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39006261

RESUMO

BACKGROUND: Percutaneous Endoscopic Lumbar Discectomy (PELD) has emerged as routine treatment for lumbar disc herniation (LDH) due to its minimal invasiveness and quick recovery. However, PELD demands high precision from the surgeon, as the risk of intraoperative complications is substantial, including potential damage to the nerve root and dura, and a higher likelihood of recurrence post-surgery. Thus, preoperative planning utilizing CT and MRI imaging is essential. METHODS: In this study, the clinical data of 140 patients treated with PELD for LDH from January 2021 to December 2023 were retrospectively analyzed. Patients were categorized into two groups based on whether CT and MRI registration (CMR) was employed for surgical planning: a CMR group (n=68) and a control group (n=72). Data collected included surgery time, hospital stay duration, and scores from the Visual Analog Scale (VAS) for low back and leg pain, as well as the Japanese Orthopaedic Association Lumbar Spine Score (JOA). Differences between the two groups were assessed using the Student's t-test. RESULTS: No significant difference was found in hospital stay length between the groups (P=0.277). Surgery time was significantly shorter in the CMR group (P<0.001). Prior to surgery, no significant differences in VAS scores for leg and low back pain were observed between the groups (P=0.341 and P=0.131, respectively); however, at 2 months postoperatively, both scores were significantly lower in the CMR group (P<0.001 and P=0.002, respectively). Similarly, no difference in preoperative JOA scores was noted (P=0.750), but at 2 months postoperative, the CMR group exhibited significantly higher scores (P<0.001). CONCLUSION: Compared with the traditional PELD, the preoperative use of CMR has shown to reduce surgery time, alleviate leg and low back pain, and increase the lumbar JOA score at 2 months after surgery, underscoring its efficacy in enhancing surgical outcomes.

9.
Brain Res Bull ; 216: 111036, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39084570

RESUMO

Amyotrophic lateral sclerosis (ALS) is a fatal neurological disease characterized by the progressive destruction of the neuromuscular junction (NMJ) and the degeneration of motor neurons, eventually leading to atrophy and paralysis of voluntary muscles responsible for motion and breathing. NMJs, synaptic connections between motor neurons and skeletal muscle fibers, are extremely fragile in ALS. To determine the effects of early electroacupuncture (EA) intervention on nerve reinnervation and regeneration following injury, a model of sciatic nerve injury (SNI) was first established using SOD1G93A mice, and early electroacupuncture (EA) intervention was conducted at Baihui (DU20), and bilateral Zusanli (ST36). The results revealed that EA increased the Sciatic nerve Functional Index, the structural integrity of the gastrocnemius muscles, and the cross-sectional area of muscle fibers, as well as up-regulated the expression of acetylcholinesterase and facilitated the co-location of α7 nicotinic acetate choline receptors and α-actinin. Overall, these results suggested that EA can promote the repair and regeneration of injured nerves and delay NMJ degeneration in SOD1G93A-SNI mice. Moreover, analysis of the cerebral cortex demonstrated that EA alleviated cortical motor neuron damage in SOD1G93A mice, potentially attributed to the inhibition of the cyclic GMP-AMP synthase-stimulator of interferon genes pathway and the release of interferon-ß suppressing the activation of natural killer cells and the secretion of interferon-γ, thereby further inhibiting microglial activation and the expression of inflammatory factors. In summary, EA delayed the degeneration of NMJ and mitigated the loss of cortical motor neurons, thus delaying disease onset, accompanied by alleviation of muscle atrophy and improvements in motor function in SOD1G93A mice.


Assuntos
Esclerose Lateral Amiotrófica , Eletroacupuntura , Camundongos Transgênicos , Neurônios Motores , Junção Neuromuscular , Animais , Eletroacupuntura/métodos , Junção Neuromuscular/patologia , Junção Neuromuscular/metabolismo , Neurônios Motores/patologia , Neurônios Motores/fisiologia , Camundongos , Esclerose Lateral Amiotrófica/terapia , Esclerose Lateral Amiotrófica/patologia , Esclerose Lateral Amiotrófica/genética , Modelos Animais de Doenças , Masculino , Degeneração Neural/terapia , Degeneração Neural/patologia , Músculo Esquelético/patologia , Superóxido Dismutase-1/genética , Superóxido Dismutase-1/metabolismo , Nervo Isquiático/lesões , Nervo Isquiático/patologia , Camundongos Endogâmicos C57BL
10.
Genomics ; 116(3): 110844, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38608737

RESUMO

The study demonstrated that melatonin (MT) can induce the development of secondary hair follicles in Inner Mongolian cashmere goats through the Wnt10b gene, leading to secondary dehairing. However, the mechanisms underlying the expression and molecular function of Wnt10b in dermal papilla cells (DPC) remain unknown. This research aimed to investigate the impact of MT on DPC and the regulation of Wnt10b expression, function, and molecular mechanisms in DPC. The findings revealed that MT promotes DPC proliferation and enhances DPC activity. Co-culturing DPC with overexpressed Wnt10b and MT showed a significant growth promotion. Subsequent RNA sequencing (RNA-seq) of overexpressed Wnt10b and control groups unveiled the regulatory role of Wnt10b in DPC. Numerous genes and pathways, including developmental pathways such as Wnt and MAPK, as well as processes like hair follicle morphogenesis and hair cycle, were identified. These results suggest that Wnt10b promotes the growth of secondary hair follicles in Inner Mongolian cashmere goats by regulating crucial factors and pathways in DPC proliferation.


Assuntos
Proliferação de Células , Cabras , Folículo Piloso , Melatonina , Proteínas Wnt , Animais , Folículo Piloso/metabolismo , Folículo Piloso/citologia , Folículo Piloso/crescimento & desenvolvimento , Cabras/genética , Cabras/metabolismo , Melatonina/farmacologia , Melatonina/metabolismo , Proteínas Wnt/metabolismo , Proteínas Wnt/genética , Células Cultivadas
11.
Food Sci Nutr ; 12(4): 2917-2931, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38628198

RESUMO

Sinapic acid (SA) is renowned for its many pharmacological activities as a polyphenolic compound. The cause of polycystic ovary syndrome (PCOS), a commonly encountered array of metabolic and hormonal abnormalities in females, has yet to be determined. The present experiment was performed to evaluate the antifibrotic properties of SA in rats with letrozole-induced PCOS-related ovarian fibrosis. SA treatment successfully mitigated the changes induced by letrozole in body weight (BW) (p < .01) and relative ovary weight (p < .05). Histological observation revealed that SA reduced the number of atretic and cystic follicles (AFs) and (CFs) (p < .01), as well as ovarian fibrosis, in PCOS rats. Additionally, SA treatment impacted the serum levels of sex hormones in PCOS rats. Luteinizing hormone (LH) and testosterone (T) levels were decreased (p < .01, p < .05), and follicle-stimulating hormone (FSH) levels were increased (p < .05). SA administration also decreased triglyceride (TG) (p < .01) and total cholesterol (TC) levels (p < .05) and increased high-density lipoprotein cholesterol (HDL-C) levels (p < .01), thereby alleviating letrozole-induced metabolic dysfunction in PCOS rats. Furthermore, SA treatment targeted insulin resistance (IR) and increased the messenger RNA (mRNA) levels of antioxidant enzymes in the ovaries of PCOS rats. Finally, SA treatment enhanced the activity of peroxisome proliferator-activated receptor-γ (PPAR-γ), reduced the activation of transforming growth factor-ß1 (TGF-ß1)/Smads, and decreased collagen I, α-smooth muscle actin (α-SMA), and connective tissue growth factor (CTGF) levels in the ovaries of PCOS rats. These observations suggest that SA significantly ameliorates metabolic dysfunction and oxidative stress and ultimately reduces ovarian fibrosis in rats with letrozole-induced PCOS.

12.
J Nanobiotechnology ; 22(1): 132, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38532378

RESUMO

BACKGROUND: Cardiovascular diseases (CVDs) have the highest mortality worldwide. Human pluripotent stem cells (hPSCs) and their cardiomyocyte derivatives (hPSC-CMs) offer a valuable resource for disease modeling, pharmacological screening, and regenerative therapy. While most CVDs are linked to significant over-production of reactive oxygen species (ROS), the effects of current antioxidants targeting excessive ROS are limited. Nanotechnology is a powerful tool to develop antioxidants with improved selectivity, solubility, and bioavailability to prevent or treat various diseases related to oxidative stress. Cerium oxide nanozymes (CeONZs) can effectively scavenge excessive ROS by mimicking the activity of endogenous antioxidant enzymes. This study aimed to assess the nanotoxicity of CeONZs and their potential antioxidant benefits in stressed human embryonic stem cells (hESCs) and their derived cardiomyocytes (hESC-CMs). RESULTS: CeONZs demonstrated reliable nanosafety and biocompatibility in hESCs and hESC-CMs within a broad range of concentrations. CeONZs exhibited protective effects on the cell viability of hESCs and hESC-CMs by alleviating excessive ROS-induced oxidative stress. Moreover, CeONZs protected hESC-CMs from doxorubicin (DOX)-induced cardiotoxicity and partially ameliorated the insults from DOX in neonatal rat cardiomyocytes (NRCMs). Furthermore, during hESCs culture, CeONZs were found to reduce ROS, decrease apoptosis, and enhance cell survival without affecting their self-renewal and differentiation potential. CONCLUSIONS: CeONZs displayed good safety and biocompatibility, as well as enhanced the cell viability of hESCs and hESC-CMs by shielding them from oxidative damage. These promising results suggest that CeONZs may be crucial, as a safe nanoantioxidant, to potentially improve the therapeutic efficacy of CVDs and be incorporated into regenerative medicine.


Assuntos
Cério , Miócitos Cardíacos , Células-Tronco Pluripotentes , Humanos , Ratos , Animais , Espécies Reativas de Oxigênio/metabolismo , Estresse Oxidativo , Diferenciação Celular , Antioxidantes/farmacologia , Doxorrubicina/farmacologia
13.
Stem Cell Res Ther ; 15(1): 31, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38317221

RESUMO

BACKGROUND: Transcription factors HAND1 and HAND2 (HAND1/2) play significant roles in cardiac organogenesis. Abnormal expression and deficiency of HAND1/2 result in severe cardiac defects. However, the function and mechanism of HAND1/2 in regulating human early cardiac lineage commitment and differentiation are still unclear. METHODS: With NKX2.5eGFP H9 human embryonic stem cells (hESCs), we established single and double knockout cell lines for HAND1 and HAND2, respectively, whose cardiomyocyte differentiation efficiency could be monitored by assessing NKX2.5-eGFP+ cells with flow cytometry. The expression of specific markers for heart fields and cardiomyocyte subtypes was examined by quantitative PCR, western blot and immunofluorescence staining. Microelectrode array and whole-cell patch clamp were performed to determine the electrophysiological characteristics of differentiated cardiomyocytes. The transcriptomic changes of HAND knockout cells were revealed by RNA sequencing. The HAND1/2 target genes were identified and validated experimentally by integrating with HAND1/2 chromatin immunoprecipitation sequencing data. RESULTS: Either HAND1 or HAND2 knockout did not affect the cardiomyocyte differentiation kinetics, whereas depletion of HAND1/2 resulted in delayed differentiation onset. HAND1 knockout biased cardiac mesoderm toward second heart field progenitors at the expense of first heart field progenitors, leading to increased expression of atrial and outflow tract cardiomyocyte markers, which was further confirmed by the appearance of atrial-like action potentials. By contrast, HAND2 knockout cardiomyocytes had reduced expression of atrial cardiomyocyte markers and displayed ventricular-like action potentials. HAND1/2-deficient hESCs were more inclined to second heart field lineage and its derived cardiomyocytes with atrial-like action potentials than HAND1 single knockout during differentiation. Further mechanistic investigations suggested TBX5 as one of the downstream targets of HAND1/2, whose overexpression partially restored the abnormal cardiomyocyte differentiation in HAND1/2-deficient hESCs. CONCLUSIONS: HAND1/2 have specific and redundant roles in cardiac lineage commitment and differentiation. These findings not only reveal the essential function of HAND1/2 in cardiac organogenesis, but also provide important information on the pathogenesis of HAND1/2 deficiency-related congenital heart diseases, which could potentially lead to new therapeutic strategies.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos , Células-Tronco Embrionárias Humanas , Humanos , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Diferenciação Celular/genética , Miócitos Cardíacos/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Células-Tronco Embrionárias Humanas/metabolismo
14.
ACS Omega ; 9(1): 1230-1241, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38222654

RESUMO

Ulcerative colitis (UC) is a chronic gastrointestinal disease that results from repeated inflammation and serious complications. Sinapic acid (SA) is a hydroxycinnamic acid present in a variety of plants that has antioxidant, anti-inflammatory, anticancer, and other protective effects. This study investigated the antifibrotic effect of SA on chronic colitis induced by dextran sulfate sodium salt (DSS) in mice. We observed that SA could significantly reduce clinical symptoms (such as improved body weight loss, increased colon length, and decreased disease activity index score) and pathological changes in mice with chronic colitis. SA supplementation has been demonstrated to repair intestinal mucosal barrier function and maintain epithelial homeostasis by inhibiting activation of the NLRP3 inflammasome and decreasing the expression of IL-6, TNF-α, IL-17A, IL-18, and IL-1ß. Furthermore, SA could induce the expression of antioxidant enzymes (Cat, Sod1, Sod2, Mgst1) by activating the Nrf2/keap1 pathway, thus improving antioxidant capacity. Additionally, SA could increase the protein expression of downstream LC3-II/LC3-I and Beclin1 and induce autophagy by regulating the AMPK-Akt/mTOR signaling pathway, thereby reducing the production of intestinal fibrosis-associated proteins Collagen-I and α-SMA. These findings suggest that SA can enhance intestinal antioxidant enzymes, reduce oxidative stress, expedite intestinal epithelial repair, and promote autophagy, thereby ameliorating DSS-induced colitis and intestinal fibrosis.

15.
Small ; 20(8): e2305607, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37817357

RESUMO

The molecule-electrode coupling plays an essential role in photoresponsive devices with photochromic molecules, and the strong coupling between the molecule and the conventional electrodes leads to/ the quenching effect and limits the reversibility of molecular photoswitches. In this work, we developed a strategy of using transition metal dichalcogenides (TMDCs) electrodes to fabricate the thiol azobenzene (TAB) self-assembled monolayers (SAMs) junctions with the eutectic gallium-indium (EGaIn) technique. The current-voltage characteristics of the EGaIn/GaOx //TAB/TMDCs photoswitches showed an almost 100% reversible photoswitching behavior, which increased by ∼28% compared to EGaIn/GaOx //TAB/AuTS photoswitches. Density functional theory (DFT) calculations showed the coupling strength of the TAB-TMDCs electrode decreased by 42% compared to that of the TAB-AuTS electrode, giving rise to improved reversibility. our work demonstrated the feasibility of 2D TMDCs for fabricating SAMs-based photoswitches with unprecedentedly high reversibility.

16.
Inorg Chem ; 62(51): 20888-20900, 2023 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-38069675

RESUMO

The structure, bonding, and properties of a series of atypical pentanuclear nickel hydride clusters supported by electron-rich iPr3P of the type [(iPr3P)Ni]5Hn (n = 4, 6, 8; H4, H6, H8) and their anionic models where iPr3P are substituted by H- (H4', H6', H8') were investigated by density functional theory (DFT) calculations. All clusters were calculated to adopt a similar square pyramidal core geometry. Calculations indicate singlet ground states with small singlet-triplet gaps for H4 and H6, similar to previously reported experimental values. Molecular orbital theory description clusters were investigated using the simplified model complexes [HNi]5Hn5- (n = 4, 6, 8; H4', H6', H8'). The results show that there are three skeletal electron pairs (SEPs) in H4'. The addition of two molecules of H2 to form H6' and H8' results in the partial or full occupation of two degenerate MOs (e* set) that give two SEPs and one SEP, respectively. Indeed, the occupation of these low-lying weakly antibonding orbitals governs the multielectron chemistry available for these clusters and plays a role in their unique reactivity.

17.
Chempluschem ; : e202300556, 2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-38050755

RESUMO

Single-molecule optoelectronics offers opportunities for advancing integrated photonics and electronics, which also serves as a tool to elucidate the underlying mechanism of light-matter interaction. Plasmonics, which plays pivotal role in the interaction of photons and matter, have became an emerging area. A comprehensive understanding of the plasmonic excitation and modulation mechanisms within single-molecule junctions (SMJs) lays the foundation for optoelectronic devices. Consequently, this review primarily concentrates on illuminating the fundamental principles of plasmonics within SMJs, delving into their research methods and modulation factors of plasmon-exciton. Moreover, we underscore the interaction phenomena within SMJs, including the enhancement of molecular fluorescence by plasmonics, Fano resonance and Rabi splitting caused by the interaction of plasmon-exciton. Finally, by emphasizing the potential applications of plasmonics within SMJs, such as their roles in optical tweezers, single-photon sources, super-resolution imaging, and chemical reactions, we elucidate the future prospects and current challenges in this domain.

18.
Genes (Basel) ; 14(10)2023 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-37895275

RESUMO

For a long time, the construction of complete reference genomes for complex eukaryotic genomes has been hindered by the limitations of sequencing technologies. Recently, the Pacific Biosciences (PacBio) HiFi data and Oxford Nanopore Technologies (ONT) Ultra-Long data, leveraging their respective advantages in accuracy and length, have provided an opportunity for generating complete chromosome sequences. Nevertheless, for the majority of genomes, the chromosome-level assemblies generated using existing methods still miss a high proportion of sequences due to losing small contigs in the step of assembly and scaffolding. To address this shortcoming, in this paper, we propose a novel method that is able to identify and fill the gaps in the chromosome-level assembly by recalling the sequences in the lost small contigs. Experimental results on both real and simulated datasets demonstrate that this method is able to improve the completeness of the chromosome-level assembly.


Assuntos
Genoma , Sequenciamento de Nucleotídeos em Larga Escala , Análise de Sequência de DNA/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Eucariotos , Cromossomos/genética
19.
Zhen Ci Yan Jiu ; 48(10): 1009-1016, 2023 Oct 25.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-37879951

RESUMO

OBJECTIVES: To observe the effects of electroacupuncture (EA) on motor function, expression of extracellular cyclophile A(PPIA) and PPIA/nuclear factor-κB (NF-κB) signaling pathway in spinal cord of amyotrophic la-teral sclerosis (ALS) mice, so as to explore the mechanism of EA intervention in regulating extracellular PPIA on neuroinflammation in ALS mice. METHODS: Thirty ALS-SOD1G93A mice with hSOD1-G93A gene were randomly divided into model, EA and Riluzole groups , with 10 mice in each group, and other 10 ALS-SOD1G93A negative mice were used as the blank group. EA was applied to bilateral "Yanglingquan"(GB34) and "Zusanli"(ST36) for 20 min once daily, 5 days a week for 2 weeks. In the Riluzole group, riluzole solution (30 mg·kg-1·d-1) was administrated intragastrically, and the treatment time was the same as that in the EA group.Rotating rod experiment and open field experiment were used to evaluate the changes in motor function of mice .The morphology of motor neurons in the anterior horn of spinal cord was observed by HE staining.The relative protein expression levels of PPIA, TDP-43 and NF-κB in the spinal cord were detected by Western blot.The positive expression level of TDP-43 in the spinal cord was detected by immunohistochemistry. The positive expression level of PPIA in spinal cord was marked by immunofluorescence. Serum PPIA content was determined by ELISA. RESULTS: Compared with the blank group, the time of rod dropping and the total distance of open field movement in the model group were shortened (P<0.01), the number of motor neurons in the anterior horn of the spinal cord was reduced, the cell morphology was incomplete, the cell body was atrophied, the protein expression and positive expression of TDP-43 were increased (P<0.01), the protein expressions of PPIA and NF-κB in the spinal cord were increased(P<0.01), the serum content of PPIA and immunofluorescence expression of PPIA in spinal cord were increased (P<0.01). Compared with the model group, the time of rod dropping and the total distance of open field movement of mice in the EA group and the Riluzole group were prolonged (P<0.05, P<0.01), and the injury of motor neuron in the anterior horn of the spinal cord was decreased, the protein expression and positive expression of TDP-43 in the spinal cord were decreased (P<0.05, P<0.01);the relative expression levels of PPIA and NF-κB proteins were decreased (P<0.05, P<0.01), and the content of PPIA in serum and the immunofluorescence expression of PPIA in the spinal cord were decreased (P<0.05, P<0.01) in the EA group;the relative protein expression of NF-κB and fluorescence expression of PPIA in spinal cord of mice in the Riluzole group were decreased (P<0.05). CONCLUSIONS: EA intervention can improve motor function in ALS mice, and its mechanism may be related to the inhibition of PPIA/NF-κB signaling pathway by EA to alleviating neuroinflammatory response.


Assuntos
Esclerose Lateral Amiotrófica , Eletroacupuntura , Animais , Camundongos , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/terapia , Esclerose Lateral Amiotrófica/metabolismo , Proteínas de Ligação a DNA/metabolismo , Neurônios Motores/metabolismo , NF-kappa B/genética , NF-kappa B/metabolismo , Riluzol , Transdução de Sinais , Medula Espinal , Superóxido Dismutase-1/genética , Superóxido Dismutase-1/metabolismo , Peptidilprolil Isomerase/metabolismo
20.
J Am Chem Soc ; 145(39): 21679-21686, 2023 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37747934

RESUMO

The charge transport through supramolecular junctions exhibits unique quantum interference (QI) effects, which provide an opportunity for the design of supramolecular transistors. Benefiting from the configuration dependence of QI, configuration control of the supramolecular assemblies to demonstrate the QI features is a key but challenging step. In this work, we fabricated the supramolecular transistors and investigated the charge transport through the conducting channel of the individual π-stacked thiophene/phenylene co-oligomers (TPCOs) using the electrochemically gated scanning tunneling microscope break junction technique. We controlled the configuration of the supramolecular channel and switched the QI features between the anti-resonance and resonance states of the supramolecular channels. We observed the supramolecular transistor with its on/off ratio above 103 (∼1300), a high gating efficiency of ∼165 mV/dec, a low off-state leakage current of ∼30 pA, and the channel length scaled down to <2.0 nm. Density functional theory calculations suggested that the QI features in π-stacked TPCOs vary depending on the supramolecular architecture and can be manipulated efficiently by fine-tuning the supramolecular configurations. This work reveals the potential of the supramolecular channels for molecular electronics and provides a fundamental understanding of intermolecular charge transport.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA