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Rice (Oryza sativa) plants contain plastidial and cytosolic disproportionating enzymes (DPE1 and DPE2). Our previous studies showed that DPE2 acts on maltose, the major product of starch degradation in pollens, releasing one glucose to fuel pollen tube growth and fertilization, whereas DPE1 participates in endosperm starch synthesis by transferring maltooligosyl groups from amylose to amylopectin, and removing excess short maltooligosaccharides. However, little is known about their integrated function. Here, we report that the coordinated actions of DPE1 and DPE2 contribute to grain setting and filling in rice. The dpe1dpe2 mutants could not be isolated from the progeny of heterozygous parental plants but were obtained via anther culture. Unlike that reported in Arabidopsis (Arabidopsis thaliana) and potato (Solanum tuberosum), the dpe1dpe2 rice plants grew normally but only yielded a small number of empty, unfilled seeds. In the dpe1dpe2 seeds, nutrient accumulation was substantially reduced, and dorsal vascular bundles were also severely malnourished. Zymogram analyses showed that changes in activities of the major starch-synthesizing enzymes matched well with various endosperm phenotypes of mutant seeds. Mechanistically, DPE1 deficiency allowed normal starch mobilization in leaves and pollens but affected starch synthesis in endosperm, while DPE2 deficiency blocked starch degradation, resulting in substantially decreased levels of the sugars available for pollen tube growth and grain filling. Overall, our results demonstrate the great potential of DPE1-DPE2 as an important regulatory module to realize higher crop yields and present a promising target for regulating nutrient accumulation in cereal crop endosperm.
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Hydrogenation-Disproportionation-Desorption-Recombination (HDDR) Nd2Fe14B particles have excellent magnetic properties, but the magnetic properties of powder are not uniform across different particle sizes. The remanence and maximum magnetic energy products of samples with a particle size of 120 µm are 14.0 kGs and 41.35 MGOe, while the products of samples with a particle size of 60 µm are only 13.3 kGs and 36.31 MGOe. The macroscopic morphology of HDDR Nd2Fe14B particles and the gradient distribution of microstructures in different micro-regions were observed. By modifying the macroscopic morphology of the particles, the poorly oriented clusters on the surface of the particles were precisely eliminated, and the remanence and maximum magnetic energy products of the particles increased to 14.5 kGs and 45 MGOe, respectively. Compared with the original particles, the samples after mechanical grinding had better grain arrangement. The effects of the nanocrystalline c-axis and field misalignment angle θ on the magnetic properties of HDDR Nd2Fe14B particles were investigated through micromagnetic simulation. The targeted removal of macroscopic defects on the particle surface contributed to a 3.6% increase in remanence and an 8.8% increase in the maximum magnetic energy product, offering a promising approach to enhance the microstructure of high-performance HDDR Nd2Fe14B particles.
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OBJECTIVES: To observe the effect of electroacupuncture (EA) at "Neiguan"(PC6) on cardiac function, cardiac morphology and transient receptor potential channel (TRPC) protein expressions in myocardial tissue of mice with myocardial hypertrophy, so as to explore its mechanisms underlying improvement of myocardial hypertrophy. METHODS: Forty-five male C57BL/6 mice were randomly divided into control, model and EA groups (15 mice/group). The myocardial hypertrophy model was established by subcutaneous injection of isoproterenol hydrochloride (15 mg·kg-1·d-1) for 14 days. The mice of the control group received subcutaneous injection of same amount of normal saline. The mice of the EA group received EA stimulation (frequency of 2 Hz, intensity of 1 mA) of bilateral PC6 for 20 min each time, once a day for 14 consecutive days. After the intervention, the body weight, tibia length and heart weight were measured. The left ventricular ejection fraction (EF), fractional shortening index (FS), left ventricular end-systolic volume (LVEV), left ventricular end-systolic internal diameter (LVID) and left ventricular posterior wall thickness (LVPW) were measured by using echocardiography for evaluating the cardiac function. The mean number and surface area of myocardial cells was detected by wheat germ agglutinin (WGA) staining, and changes of the cardiac morphology were observed under light microscopy after HE staining. The expression levels of TRPC1, TRPC3, TRPC4 and TRPC6 (TRPC1/3/4/6) in the myocardial tissue were detected by real-time quantitative PCR (qPCR) and Western blot, separately. RESULTS: Compared with the control group, the heart-body weight ratio(P<0.05) and heart-weight-to-tibia-length ratio (P<0.01), LVEV and LVID levels, the relative surface area, left ventricular area ratio, and the expression levels of cardiac TRPC1/3/4/6 were significantly increased (P<0.01, P<0.05), while the EF, FS, LVPW, number of cardiomyocytes, and the left ventricular posterior wall ratio were obviously decreased (P<0.01, P<0.05) in the model group. In comparison with the model group, the heart/body weight ratio, heart-weight-to-tibia-length ratio, LVEV and LVID levels, relative surface area, left ventricular area ratio, and the expression levels of cardiac TRPC1/3/4/6 were significantly decreased (P<0.01, P<0.05), while the EF, FS, LVPW, number of cardiomyocytes and left ventricular posterior wall ratio were significantly increased (P<0.01, P<0.05) in the EA group. H.E. staining showed disordered arrangement of cardiomyocytes and obvious myocardial interstitial inflammatory cell infiltration in the model group, and evident reduction of degree of cardiac fibrosis and interstitial edema in the EA group. CONCLUSIONS: EA of PC6 can improve the cardiac function and cardiac morphology in mice with myocardial hypertrophy, which may be related to its functions in down-regulating the expression of transient receptor potential channels.
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Eletroacupuntura , Camundongos Endogâmicos C57BL , Miocárdio , Animais , Camundongos , Masculino , Humanos , Miocárdio/metabolismo , Canais de Potencial de Receptor Transitório/metabolismo , Canais de Potencial de Receptor Transitório/genética , Cardiomegalia/metabolismo , Cardiomegalia/terapia , Cardiomegalia/genética , Cardiomegalia/fisiopatologia , Pontos de Acupuntura , Canais de Cátion TRPC/metabolismo , Canais de Cátion TRPC/genéticaRESUMO
Oleanolic acid and its derivatives are widely used in the pharmaceutical, agricultural, cosmetic and food industries. Previous studies have shown that oleanolic acid production levels in engineered cell factories are low, which is why oleanolic acid is still widely extracted from traditional medicinal plants. To construct a highly efficient oleanolic acid production strain, rate-limiting steps were regulated by inducible promoters and the expression of key genes in the oleanolic acid synthetic pathway was enhanced. Subsequently, precursor pool expansion, pathway refactoring and diploid construction were considered to harmonize cell growth and oleanolic acid production. The multi-strategy combination promoted oleanolic acid production of up to 4.07 g/L in a 100 L bioreactor, which was the highest level reported.
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Ácido Oleanólico , Saccharomyces cerevisiae , Ácido Oleanólico/biossíntese , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Reatores Biológicos , Engenharia Metabólica/métodos , Engenharia Genética/métodos , Regiões Promotoras GenéticasRESUMO
Electroacupuncture (EA) stimulation has been shown to be beneficial in stroke rehabilitation; however, little is known about the neurological mechanism by which this peripheral stimulation approach treats for stroke. This study showed that both pyramidal and parvalbumin (PV) neuronal activity increased in the contralesional primary motor cortex forelimb motor area (M1FL) after ischemic stroke induced by focal unilateral occlusion in the M1FL. EA stimulation reduced pyramidal neuronal activity and increased PV neuronal activity. These results were obtained by a combination of fiber photometry recordings, in vivo and in vitro electrophysiological recordings, and immunofluorescence. Moreover, EA was found to regulate the expression/function of N-methyl-D-aspartate receptors (NMDARs) altered by stroke pathology. In summary, our findings suggest that EA could restore disturbed neuronal activity through the regulation of the activity of pyramidal and PV neurons. Furthermore, NMDARs we shown to play an important role in EA-mediated improvements in sensorimotor ability during stroke rehabilitation.
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Constructing relatively inexpensive nanomaterials to simulate the catalytic performance of laccase is of great significance in recent years. Although research on improving laccase-like activity by regulating ligands of copper (amino acids or small organic molecules, etc.) have achieved remarkable success. There are few reports on improving laccase-like activity by adjusting the composition of metal Cu. Here, we used perovskite hydroxide AB(OH)6 as a model to evaluate the relationship between Cu based alloys and their laccase-like activity. We found that when the Cu/Mn alloy ratio of the perovskite hydroxide A point is greater than 1, the laccase-like activity of the binary alloy perovskite hydroxide is higher than that of the corresponding single Cu. Based on the measurements of XPS and ICP-MS, we deduced that the improvements of laccase-like activity mainly attribute to the ratio of Cu+/Cu2+and the content of Cu. Moreover, two types of substrates (toxic pollutants and catechol neurotransmitters) were used to successfully demonstrated such nanozymes' excellent environmental protecting function and biosensing property. This work will provide a novel approach for the construction and application of laccase-like nanozymes in the future.
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Técnicas Biossensoriais , Cobre , Lacase , Óxidos , Titânio , Lacase/química , Lacase/metabolismo , Técnicas Biossensoriais/métodos , Cobre/química , Titânio/química , Óxidos/química , Hidróxidos/química , Compostos de Cálcio/química , Recuperação e Remediação Ambiental/métodos , Catecóis/análise , Catecóis/química , Materiais Biomiméticos/química , CatáliseRESUMO
This work has studied the co-addition of Sc and Zr elements into the Al-1.75wt%Fe-1.25wt%Ni eutectic alloy. The changes in the microstructure, electrical conductivity, and Vickers hardness of the Al-1.75wt%Fe-1.25wt%Ni-0.2wt%Sc-0.2wt%Zr alloy during heat treatment were studied. The results showed that two-step aging can effectively improve the aging response of the alloy over the single-step aging method. This was ascribed to the minimization of the diffusion difference between Sc and Zr elements. Furthermore, the homogenization treatment can also improve the aging response of the alloy by alleviating the uneven distribution of Sc and Zr. Nevertheless, the micro-alloyed elements exceeded the solid solubility limit in the Al-1.75wt%Fe-1.25wt%Ni-0.2wt%Sc-0.2wt%Zr alloy, and their strengthening effect has ever achieved the best prospect. Finally, both Sc and Zr contents were reduced simultaneously, and the aging response of the Al-1.75wt%Fe-1.25wt%Ni-0.15wt%Sc-0.1wt%Zr alloy was improved by optimized heat treatment. The underlying mechanisms for this alloy design and the corresponding microstructure-mechanical property relationship were analytically discussed.
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On-chip micro-ring resonators (MRRs) with low loss and large free spectral ranges (FSRs) are important for photonic devices. So far, ultra-low-loss silicon-nitride (Si3N4) waveguides are primarily fabricated in laboratories, as they often demand special processes to reduce transmission losses. While, Si3N4 waveguides fabricated by the standard multi-project wafer (MPW)-based processes often suffer from significant sidewall scattering, resulting in high scattering losses. Here, we present an innovative approach to photonics by introducing a compact and multi-mode structure. This approach significantly reduces the contact between the optical field and the rough sidewalls in the high-confinement Si3N4 waveguide. By incorporating modified Euler bends, and a weakly tapered gap directional coupler, adiabatic transmission with simultaneous ultra-low loss and compact size is achieved even in 7-µm wide waveguide. Results show that the intrinsic quality factor Qi of MRR is (6.8 ± 0.4) × 106 at the wavelength of 1550â nm, which is approximately four times higher than the previously reported by the same fabrication process. An ultra-low loss of 0.051 ± 0.003â dB/cm is achieved based on the standard LIGENTEC-AN800 technology. This accomplishment addresses a critical challenge in high-confinement waveguides. Our work provides new insights into the low propagation loss in Si3N4 waveguides and provides a broader prospect for integrated photonics in the ultra-high-Q regime.
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The modulus of traditional biomedical hydrogels increases exponentially meditated by dehydration-stiffing mechanism, which leads to the failure of interface matching between hydrogels and soft tissue wounds. It is found in the study that the dual-solvent gels exhibit dehydration-toughening mechanism with the slowly increasing modulus that are always match the soft tissue wounds. Therefore, dual-solvent glycerol hydrogels (GCFen-gly DGHs) are prepared with hydrophobically modified catechol chitosan (hmCSC) and gelatin based on the supramolecular interactions. GCFen-gly DGHs exhibit excellent water retention capacity with a total solvent content exceeding 80%, permanent skin-like modulus within a range of 0.45 to 4.13 kPa, and stable photothermal antibacterial abilities against S, aureus, E. coli, as well as MRSA. Infectious full-thickness rat skin defect model and tissue section analysis indicate that GCFen-gly DGHs are able to accelerate infectious wound healing by alleviating the inflammatory response, promoting granulation tissue growth, re-epithelialization, collagen deposition, and vascular regeneration. As a result, GCFen-gly DGHs is expected to become the next-generation biological gel materials for infectious wound treatment.
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Antibacterianos , Quitosana , Hidrogéis , Cicatrização , Animais , Hidrogéis/química , Hidrogéis/farmacologia , Ratos , Cicatrização/efeitos dos fármacos , Quitosana/química , Antibacterianos/química , Antibacterianos/farmacologia , Ratos Sprague-Dawley , Staphylococcus aureus/efeitos dos fármacos , Infecção dos Ferimentos/tratamento farmacológico , Escherichia coli/efeitos dos fármacos , Gelatina/química , Masculino , Glicerol/química , Glicerol/farmacologia , Pele/efeitos dos fármacos , ViscosidadeRESUMO
The epidermis of a deep burn wound is entirely absent and the dermal tissue sustains significant damage, accompanied by a substantial amount of tissue exudate. Due to the excessively humid environment, the formation of a scab on the wound becomes challenging, leaving it highly vulnerable to external bacterial invasion. In this work, a core-shell dual-drug-loaded nanofiber dressing was prepared by electrospinning technology for the synergistic treatment of a deep burn. The shell layer consists of polycaprolactone and chitosan encapsulating asiaticoside, with the core layer comprising the clathrate of 2-hydroxypropyl-ß-cyclodextrin and curcumin. Upon application to the wound, the dual-drug-loaded nanofiber dressing exhibited rapid release of asiaticoside, stimulating collagen deposition and promoting tissue repair. The core-shell structure and clathrate configuration ensured sustained release of curcumin, providing antibacterial and anti-inflammatory functions for the wound. The mechanical strength, broad-spectrum antibacterial ability, cell proliferation, and adhesion ability of the nanofiber dressing showed its potential as a medical dressing. This dressing also exhibited excellent wound healing promoting effects in the SD rat burn model. This paper provides a strategy for burn wound healing.
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Queimaduras , Curcumina , Nanofibras , Triterpenos , Ratos , Animais , Nanofibras/uso terapêutico , Nanofibras/química , Curcumina/farmacologia , Curcumina/uso terapêutico , Ratos Sprague-Dawley , Queimaduras/tratamento farmacológico , Antibacterianos/uso terapêutico , BandagensRESUMO
AIMS: Electroacupuncture (EA) at the Lianquan (CV23) could alleviate swallowing dysfunction. However, current knowledge of its neural modulation focused on the brain, with little evidence from the periphery. Transient receptor potential channel vanilloid subfamily 1 (TRPV1) is an ion channel predominantly expressed in sensory neurons, and acupuncture can trigger calcium ion (Ca2+ ) wave propagation through active TRPV1 to deliver signals. The present study aimed to investigate whether TRPV1 mediated the signal of EA to the primary sensory cortex (S1) during regulation of swallowing function. METHODS: Blood perfusion was evaluated by laser speckle contrast imaging (LSCI), and neuronal activity was evaluated by fiber calcium recording and c-Fos staining. The expression of TRPV1 was detected by RNA-seq analysis, immunofluorescence, and ELISA. In addition, the swallowing function was assessed by in vivo EMG recording and water consumption test. RESULTS: EA treatment potentiated blood perfusion and neuronal activity in the S1, and this potentiation was absent after injecting lidocaine near CV23. TRPV1 near CV23 was upregulated by EA-CV23. The blood perfusion at CV23 was decreased in the TRPV1 hypofunction mice, while the blood perfusion and the neuronal activity of the S1 showed no obvious change. These findings were also present in post-stroke dysphagia (PSD) mice. CONCLUSION: The TRPV1 at CV23 after EA treatment might play a key role in mediating local blood perfusion but was not involved in transferring EA signals to the central nervous system (CNS). These findings collectively suggested that TRPV1 may be one of the important regulators involved in the mechanism of EA treatment for improving swallowing function in PSD.
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Terapia por Acupuntura , Eletroacupuntura , Acidente Vascular Cerebral , Camundongos , Animais , Eletroacupuntura/métodos , Deglutição/fisiologia , Cálcio/metabolismo , Sistema Nervoso Central/metabolismo , Canais de Cátion TRPV/metabolismo , Pontos de AcupunturaRESUMO
Despite increasing evidence that patients with heart failure (HF) are susceptible to sarcopenia, the reason for the association is not well understood. The purpose of this study is to explore further the molecular mechanism of the occurrence of this complication. Gene expression datasets for HF (GSE57345) and Sarcopenia (GSE1428) were obtained from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified using 'edgeR' and "limma" packages of R, and their functions were analyzed using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). Protein-protein interaction (PPI) networks were constructed and visualized using Search Tool for the Retrieval of Interacting Genes (STRING) and Cytoscape. Hub genes were selected using the plugin cytoHubba and validation with GSE76701 for HF and GSE136344 for Sarcopenia. The related pathways and molecular mechanisms of the hub genes were performed by Gene set enrichment analysis (GSEA). The statistical analyses were performed using R software. P < 0.05 was considered statistically significant. A total of 114 common DEGs were found. Pathways related to growth factor, Insulin secretion and cGMP-PKG were enriched in both HF and Sarcopenia. CYP27A1, KCNJ8, PIK3R5, TIMP2, CXCL12, KIT, and VCAM1 were found to be significant hub genes after validation, with GSEA emphasizing the importance of the hub genes in the regulation of the inflammatory response. Our study reveals that HF and Sarcopenia share common pathways and pathogenic mechanisms. These findings may suggest new directions for future research into the underlying pathogenesis.
Apesar das evidências crescentes de que pacientes com insuficiência cardíaca (IC) são suscetíveis à sarcopenia, o motivo da associação não é bem compreendido. O objetivo deste estudo é explorar ainda mais o mecanismo molecular de ocorrência desta complicação. Conjuntos de dados de expressão gênica para HF (GSE57345) e Sarcopenia (GSE1428) foram obtidos do banco de dados Gene Expression Omnibus (GEO). Genes diferencialmente expressos (DEGs) foram identificados usando pacotes 'edgeR' e "limma" de R, e suas funções foram analisadas usando Gene Ontology (GO) e a Enciclopédia de Genes e Genomas de Kyoto (KEGG). Redes de interação proteína-proteína (PPI) foram construídas e visualizadas usando Search Tool for the Retrieval of Interacting Genes (STRING) e Cytoscape. Os genes hub foram selecionados usando o plugin cytoHubba e validados com GSE76701 para IC e GSE136344 para Sarcopenia. As vias relacionadas e os mecanismos moleculares dos genes hub foram realizados pela análise de enriquecimento de genes (GSEA). As análises estatísticas foram realizadas no software R. P < 0,05 foi considerado estatisticamente significativo. Foram encontrados 114 DEGs comuns. As vias relacionadas ao fator de crescimento, secreção de insulina e cGMP-PKG estavam enriquecidas tanto na IC quanto na sarcopenia. Descobriu-se que CYP27A1, KCNJ8, PIK3R5, TIMP2, CXCL12, KIT e VCAM1 são genes hub significativos após validação com GSEA enfatizando a importância dos genes hub na regulação da resposta inflamatória. Nosso estudo revela que a IC e a Sarcopenia compartilham vias e mecanismos patogênicos comuns. Estes achados podem sugerir novas direções para pesquisas futuras sobre a patogênese subjacente.
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Insuficiência Cardíaca , Sarcopenia , Humanos , Biologia de Sistemas , Perfilação da Expressão Gênica , Redes Reguladoras de Genes , Sarcopenia/genética , Biologia Computacional , Insuficiência Cardíaca/genéticaRESUMO
As one of the commonly used therapies for pain-related diseases in clinical practice, electroacupuncture (EA) has been proven to be effective. In chronic pain, neurons in the anterior cingulate cortex (ACC) have been reported to be hyperactive, while the mechanism by which cannabinoid type 1 receptors (CB1Rs) in the ACC are involved in EA-mediated analgesic mechanisms remains to be elucidated. In this study, we investigated the potential central mechanism of EA analgesia. A combination of techniques was used to detect the expression and function of CB1R, including quantitative real-time PCR (q-PCR), western blot (WB), immunofluorescence (IF), enzyme-linked immunosorbent assay (ELISA), and in vivo multichannel optical fibre recording, and neuronal activity was examined by in vivo two-photon imaging and in vivo electrophysiological recording. We found that the hyperactivity of pyramidal neurons in the ACC during chronic inflammatory pain is associated with impairment of the endocannabinoid system. EA at the Zusanli acupoint (ST36) can reduce the hyperactivity of pyramidal neurons and exert analgesic effects by increasing the endocannabinoid ligands anandamide (AEA), 2-arachidonoylglycerol (2-AG) and CB1R. More importantly, CB1R in the ACC is one of the necessary conditions for the EA-mediated analgesia effect, which may be related to the negative regulation of the N-methyl-D-aspartate receptor (NMDAR) by the activation of CB1R downregulating NR1 subunits of NMDAR (NR1) via histidine triad nucleotide-binding protein 1 (HINT1). Our study suggested that the endocannabinoid system in the ACC plays an important role in acupuncture analgesia and provides evidence for a central mechanism of EA-mediated analgesia.
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A moxibustion device with the functions of auricular fumigation moxibustion and heat-sensitive moxibustion is designed. The smoke of the ignited moxa stick is used for the fumigation moxibustion at the external auditory canal, while the heat generated works on Dazhui (GV 14) for heat-sensitive moxibustion. The device consists of five parts, i.e. combustion chamber, smoke pipe, smoke processing chamber, power module and connector. It solves the limitations such as unpleasant experience in treatment, unfavorable temperature control, easy scalding and excessive manual dependence induced by usual fumigation moxibustion and during heat-sensitive moxibustion. This moxibustion device may improve the safety and convenience when delivering the treatment with fumigation moxibustion and heat-sensitive moxibustion, as well as the work efficiency of medical staff.
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Moxibustão , Humanos , Temperatura Alta , Fumigação , Fumaça , TemperaturaRESUMO
Acupuncture at Lianquan (CV23) acupoint has been shown to improve swallowing function in poststroke dysphagia (PSD). This improvement is supposed to be associated with the regulation of neuronal activity in the contralateral primary motor cortex (M1), while the underlying mechanism still needs to be elucidated. Perineuronal nets (PNNs) are well-known to be involved in the regulation of neuronal activity. Thus, we here aimed to detect the role of PNNs in the contralateral M1 hemisphere in the electroacupuncture (EA)-mediated effect in male mice. The results were obtained from a combination of methods, including in vitro slice electrophysiological recording, in vivo electrophysiological recording, and immunofluorescent staining in male mice. These results showed a decrease of the excitatory postsynaptic currents (sEPSCs) and no alteration of the inhibitory postsynaptic currents (sIPSCs) in the GABAergic neurons and the tonic inhibition in the excitatory neurons in the contralateral M1 after stroke induction, and EA recovered the impaired sEPSCs in the GABAergic neurons. We further found that the effect of EA-induced increase of c-Fos expression, enhancement of spike firing, potentiation of sEPSCs in the excitatory neurons, and improvement of swallowing function were all blocked by the removal of PNNs in the contralateral M1. In conclusion, the PNNs in the contralateral M1 was suggested to be participated in stroke pathogenesis and might be associated with the EA-mediated swallowing function rehabilitation of PSD in male mice. Our study provides insight into how PNNs might be involved in the mechanism of EA treatment for stroke rehabilitation.
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Transtornos de Deglutição , Eletroacupuntura , Acidente Vascular Cerebral , Camundongos , Animais , Masculino , Eletroacupuntura/efeitos adversos , Eletroacupuntura/métodos , Transtornos de Deglutição/complicações , Transtornos de Deglutição/terapia , Neurônios/metabolismo , Matriz Extracelular/metabolismo , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/metabolismoRESUMO
During the drilling process in the dolomite formation of the Leikoupo formation in western Sichuan, downhole obstruction frequently occurs, which seriously hinders the efficient development of oil and gas resources on site. In view of the problems of borehole stability existing in this type of formation, the geological characteristics, underground complexity, and fracture development of the research block were systematically identified and analyzed, and the physical parameters and mechanical properties of the rock were defined through physical and chemical tests and an understanding of the mechanical properties of the rock. These studies revealed the mechanism of borehole instability and the main factors influencing fractured dolomite formation. Finally, a model of borehole collapse pressure within fractured dolomite formation was established by selecting the appropriate strength criterion as the criterion of borehole instability. The results show that the dolomite fractures of the Leikoupo formation are relatively developed, the formation is dominated by low-angle fractures, and the core integrity is not high. The development of formation fractures has an obvious effect on the mechanical strength of rock, which decreases to different degrees with the decrease in the integrity coefficient of the rock mass, and the anisotropy of the rock's mechanical strength is obvious. The empirical parameters of the generalized Hoek-Brown (H-B) strength criterion were quantified by introducing rock mass acoustic data, and the accuracy of the improved generalized H-B strength criterion was evaluated using triaxial test data. Taking the M-C criterion, the generalized H-B criterion based on acoustic wave, the D-P criterion, and the weak surface strength criterion as wellbore instability criteria, combined with the distribution of wellbore stress, a prediction model of wellbore stability considering the degree of dolomite formation fragmentation was established. The results demonstrate that the generalized H-B criterion model based on acoustic waves can be used to evaluate the wellbore stability of dolomite fracture formation with more than one group of fractures. These research results have certain guiding significance for efficient and safe drilling in fractured dolomite formations.
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Hevea brasiliensis is the main source of natural rubber. Restricted by its tropical climate conditions, the planting area in China is limited, resulted in a low self-sufficiency. Periploca sepium which can produce natural rubber is a potential substitute plant. cis-prenyltransferase (CPT), small rubber particle protein (SRPP) and rubber elongation factor (REF) are key enzymes involved in the biosynthesis of cis-1, 4-polyisoprene, the main component of natural rubber. In this study, we cloned the promoter sequences of CPT, SRPP and REF through chromosome walking strategy. The spatial expression patterns of the three promoters were analyzed using GUS (ß-glucuronidase) as a reporter gene driven by the promoters through Agrobacterium-mediated genetic transformation. The results showed that GUS driven by CPT, SRPP or REF promoter was expressed in leaves and stems, especially in the leaf vein and vascular bundle. The GUS activity in stems was higher than that in leaf. This study provided a basis for analyzing the biosynthesis mechanism of natural rubber and breeding new varieties of high yield natural rubber.
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Fatores de Alongamento de Peptídeos , Periploca , Fatores de Alongamento de Peptídeos/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Periploca/genética , Periploca/metabolismo , Borracha , Melhoramento Vegetal , Clonagem MolecularRESUMO
Tumor-associated macrophages (TAMs) play a critical role in tumor progression and metastasis. Modulation of TAM polarization is one of the most effective strategies to change the immunosuppressive tumor microenvironment (TME). In this study, organic polymer nanoparticles (CPHT) were prepared using hyaluronic acid (HA)-conjugated disulfide-bonded polyethylene imide (PEIS) as a carrier through a self-assembly strategy. These nanoparticles were modified by transferrin (Tf) and loaded with chlorin e6 (Ce6). The results showed that CPHT had good dispersion with a particle size of about 30 nm. CPHT gradually disintegrated under the exposure with a high concentration of glutathione (GSH) in tumor cells, proving the possibility for the controlled release of Ce6 and photodynamic therapy. An in vitro test showed that the uptake of CPHT in tumor cells was mediated by both HA and Tf, indicating the active tumor-targeting capacity of CPHT. CPHT significantly downregulated the ratio of CD206/CD86 and triggered the upregulation of immune factors such as TNF-α and iNOS, suggesting the repolarization of TAMs. We also found that CPHT effectively induced ferroptosis in tumor cells through lipid peroxide accumulation, GSH depletion, and downregulation of lipid peroxidase (GPX4) expression. Animal experiments confirmed that CPHT not only effectively inhibited the growth of tumors in situ but also significantly decelerated the growth of the distal tumor. Elevated levels of CD86 and IFN-γ and decreased expression of CD206 were observed at the tumor sites post CPHT treatment. These results confirmed the value of CPHT as a multifunctional nanoplatform that can tune the TME and provide new hope for tumor treatment.
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Neoplasias da Mama , Nanopartículas , Fotoquimioterapia , Porfirinas , Animais , Humanos , Feminino , Polímeros/farmacologia , Macrófagos Associados a Tumor , Porfirinas/farmacologia , Linhagem Celular Tumoral , Microambiente Tumoral , Fármacos Fotossensibilizantes/farmacologiaRESUMO
With the rising demand for nuclear energy, the storage/transportation of radioactive nuclear by-products are critical safety issues for humans and the environment. These by-products are closely related to various nuclear radiations. In particular, neutron radiation requires specific protection by neutron shielding materials due to its high penetrating ability to cause irradiation damage. Herein, a basic overview of neutron shielding is presented. Since gadolinium (Gd) has the largest thermal neutron capture cross-section among various neutron absorbing elements, it is an ideal neutron absorber for shielding applications. In the last two decades, there have been many newly developed Gd-containing (i.e., inorganic nonmetallic-based, polymer-based, and metallic-based) shielding materials developed to attenuate and absorb the incident neutrons. On this basis, we present a comprehensive review of the design, processing methods, microstructure characteristics, mechanical properties, and neutron shielding performance of these materials in each category. Furthermore, current challenges for the development and application of shielding materials are discussed. Finally, the potential research directions are highlighted in this rapidly developing field.