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Intrinsically low lattice thermal conductivity ([Formula: see text]) in superionic conductors is of great interest for energy conversion applications in thermoelectrics. Yet, the complex atomic dynamics leading to superionicity and ultralow thermal conductivity remain poorly understood. Here, we report a comprehensive study of the lattice dynamics and superionic diffusion in [Formula: see text] from energy- and momentum-resolved neutron and X-ray scattering techniques, combined with first-principles calculations. Our results settle unresolved questions about the lattice dynamics and thermal conduction mechanism in [Formula: see text] We find that the heat-carrying long-wavelength transverse acoustic (TA) phonons coexist with the ultrafast diffusion of Ag ions in the superionic phase, while the short-wavelength nondispersive TA phonons break down. Strong scattering of phonon quasiparticles by anharmonicity and Ag disorder are the origin of intrinsically low [Formula: see text] The breakdown of short-wavelength TA phonons is directly related to the Ag diffusion, with the vibrational spectral weight associated to Ag oscillations evolving into stochastic decaying fluctuations. Furthermore, the origin of fast ionic diffusion is shown to arise from extended flat basins in the energy landscape and collective hopping behavior facilitated by strong repulsion between Ag ions. These results provide fundamental insights into the complex atomic dynamics of superionic conductors.
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The stretchability of polymeric materials is critical to many applications such as flexible electronics and soft robotics, yet the stretchability of conventional cross-linked linear polymers is limited by the entanglements between polymer chains. We show using molecular dynamics simulations that cross-linked ring polymers are significantly more stretchable than cross-linked linear polymers. Compared to linear polymers, the entanglements between ring polymers do not act as effective cross-links. As a result, the stretchability of cross-linked ring polymers is determined by the maximum extension of polymer strands between cross-links, rather than between trapped entanglements as in cross-linked linear polymers. The more compact conformation of ring polymers before deformation also contributes to the increase in stretchability.
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Elastómeros , Polímeros , Conformación Molecular , Simulación de Dinámica MolecularRESUMEN
Recent advances in the functional material and biomedical applications of nanorods call for a fundamental understanding of the active motion of nanorods in a viscoelastic medium. Molecular dynamics simulations are performed to investigate a model system consisting of force-driven active thin nanorods in a melt of unentangled polymers. The activeness of a thin nanorod arises from a constant external force applied uniformly along the rod. The simulations demonstrate that the active force overcomes the randomness of the diffusive motion and results in a ballistic motion along the direction of the applied force at long timescales. The constant speed of the force-driven ballistic motion is determined by the balance of the active force and the friction from the coupling of the nanorod with the polymer viscosity. The friction coefficient, which is computed as the ratio of the active force and the speed, decreases as the active force increases. The origin of the reduction in the friction coefficient is the high speed that allows the nanorod to renew its local environment faster than the relaxation time of melt chains. A scaling theory is developed to quantify the dependence of the friction coefficient on the strength of the active force. The simulations also demonstrate that the force-driven ballistic motion suppresses the rotational diffusion of the rod and cuts off the de-correlation of the rod axis with time. On the scaling level, the long-time trajectory of a force-driven active nanorod piercing through unentangled polymers may be described as a stretched array of "active blobs", where the short-time random-walk trajectory within an active blob is unperturbed by the active force.
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DHX33 has been shown to play key roles in promoting cell proliferation. We have previously found that DHX33 protein is a doublet. In this report, we discovered that DHX33 doublet is due to alternative translation initiation by two in-frame initiation codons. This is supported by studies from both cell lines and mouse models. DHX33 translation initiation from either AUG codon happens at equal efficiency. Short DHX33 protein has similar cellular location and functions with full-length DHX33. Our results suggest that leaky scanning normally occur in DHX33 mRNA translation, which may serve as a safeguard mechanism to ensure optimal DHX33 translation efficiency. This is the first report of DEAD/DEAH box proteins that can be regulated by alternative translation initiation.
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Codón Iniciador , ARN Helicasas DEAD-box/biosíntesis , ARN Helicasas DEAD-box/genética , Iniciación de la Cadena Peptídica Traduccional , Animales , Células Cultivadas , ARN Helicasas DEAD-box/química , Humanos , Isoenzimas/biosíntesis , Isoenzimas/química , Isoenzimas/genética , Ratones , Ratones Noqueados , Células 3T3 NIH , ARN Guía de Kinetoplastida/genética , Sistemas de LecturaRESUMEN
Supported metal nanoparticles play key roles in nanoelectronics, sensors, energy storage/conversion, and catalysts for the sustainable production of fuels and chemicals. Direct observation of the dynamic processes of nanocatalysts at high temperatures and the confinement of supports is of great significance to investigate nanoparticle structure and functions for practical utilization. Here, in situ high-resolution transmission electron microscopy photos and videos are combined with dynamics simulations to reveal the real-time dynamic behavior of Pt nanocatalysts at operation temperatures. Amorphous Pt surface on moving and deforming particles is the working structure during the high operation temperature rather than a static crystal surface and immobilization on supports as proposed before. The free rearrangement of the shape of Pt nanoparticles allows them to pass through narrow windows, which is generally considered to immobilize the particles. The Pt particles, no matter what their sizes, prefer to stay inside nanopores even when they are fast moving near an opening at temperatures up to 900 °C. The porous confinement also blocks the sintering of the particles under the confinement size of pores. These contribute to the continuous high activity and stability of Pt nanocatalysts inside nanoporous supports during a long-term evaluation of catalytic reforming reaction.
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Understanding the interaction between nanoparticles (NPs) and cell membranes is crucial for the design of NP-based drug delivery systems and for the assessment of the risks exerted by the NPs. Recent experimental and theoretical studies have shown that cell membranes can mediate attraction between NPs and form tubular structures to wrap multiple NPs. However, the cooperative wrapping process is still not well understood, and the shape effect of NPs is not considered. In this article, we use large-scale coarse-grained molecular dynamics (CGMD) simulations to study the cooperative wrapping of NPs when a varying number of NPs adhered to the membrane. Spherical, prolate and oblate NPs of different sizes are considered in this study. We find that, in addition to tubular structures, the membrane can form a pocket-like and a handle-like structure to wrap multiple NPs depending on the size and shape of the NPs. Furthermore, we find that NPs can mediate membrane hemifusion or fusion during this process. Our findings provide new insights into the interaction of NPs with the cell membrane.
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Membrana Celular/química , Lípidos de la Membrana/química , Tamaño de la Partícula , Conformación Molecular , Simulación de Dinámica Molecular , NanopartículasRESUMEN
Mucus is a viscoelastic gel layer that typically protects exposed surfaces of the gastrointestinal (GI) tract, lung airways, and other mucosal tissues. Particles targeted to these tissues can be efficiently trapped and removed by mucus, thereby limiting the effectiveness of such drug delivery systems. In this study, we experimentally and theoretically demonstrated that cylindrical nanoparticles (NPs), such as mesoporous silica nanorods and calcium phosphate nanorods, have superior transport and trafficking capability in mucus compared with spheres of the same chemistry. The higher diffusivity of nanorods leads to deeper mucus penetration and a longer retention time in the GI tract than that of their spherical counterparts. Molecular simulations and stimulated emission of depletion (STED) microscopy revealed that this anomalous phenomenon can be attributed to the rotational dynamics of the NPs facilitated by the mucin fibers and the shear flow. These findings shed new light on the shape design of NP-based drug delivery systems targeted to mucosal and tumor sites that possess a fibrous structure/porous medium.
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The Toll and IMD pathways are known to be induced upon Plasmodium berghei and Plasmodium falciparum infection, respectively. It is unclear how Plasmodium or other pathogens in the blood meal and their invasion of the midgut epithelium would trigger the innate immune responses in immune cells, in particular hemocytes. Gap junctions, which can mediate both cell-to-cell and cell-to-extracellular communication, may participate in this signal transduction. This study examined whether innexins, gap junction proteins in insects, are involved in anti-Plasmodium responses in Anopheles gambiae. Inhibitor studies using carbenoxolone indicated that blocking innexons resulted in an increase in Plasmodium oocyst number and infection prevalence. This was accompanied by a decline in TEP1 levels in carbenoxolone-treated mosquitoes. Innexin AGAP001476 mRNA levels in midguts were induced during Plasmodium infection and a knockdown of AGAP001476, but not AGAP006241, caused an induction in oocyst number. Silencing AGAP001476 caused a concurrent increase in vitellogenin levels, a TEP1 inhibitor, in addition to a reduced level of TEP1-LRIM1-APL1C complex in hemolymph. Both vitellogenin and TEP1 are regulated by Cactus under the Toll pathway. Simultaneous knockdown of cactus and AGAP001476 failed to reverse the near refractoriness induced by the knockdown of cactus, suggesting that the AGAP001476-mediated anti-Plasmodium response is Cactus-dependent. These data demonstrate a critical role for innexin AGAP001476 in mediating innate immune responses against Plasmodium through Toll pathway in mosquitoes.
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Anopheles/inmunología , Conexinas/inmunología , Proteínas de Insectos/inmunología , Insectos Vectores/inmunología , Plasmodium/inmunología , Animales , Anopheles/parasitología , Carbenoxolona/inmunología , Carbenoxolona/farmacología , Conexinas/genética , Conexinas/metabolismo , Femenino , Expresión Génica/inmunología , Hemolinfa/inmunología , Hemolinfa/metabolismo , Interacciones Huésped-Parásitos/efectos de los fármacos , Interacciones Huésped-Parásitos/inmunología , Inmunidad Innata/inmunología , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Insectos Vectores/parasitología , Malaria/sangre , Malaria/inmunología , Malaria/parasitología , Ratones , Microscopía Confocal , Oocistos/inmunología , Oocistos/metabolismo , Plasmodium/fisiología , Plasmodium berghei/inmunología , Plasmodium berghei/fisiología , Interferencia de ARN , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Vitelogeninas/genética , Vitelogeninas/inmunología , Vitelogeninas/metabolismoRESUMEN
We present a hollow-structured rigid nanovesicle (RNV) fabricated by a multi-stage microfluidic chip in one step, to effectively entrap various hydrophilic reagents inside, without complicated synthesis, extensive use of emulsifiers and stabilizers, and laborious purification procedures. The RNV contains a hollow water core, a rigid poly (lactic-co-glycolic acid) (PLGA) shell, and an outermost lipid layer. The formation mechanism of the RNV is investigated by dissipative particle dynamics (DPD) simulations. The entrapment efficiency of hydrophilic reagents such as calcein, rhodamineâ B and siRNA inside the hollow water core of RNV is ≈90 %. In comparison with the combination of free Dox and siRNA, RNV that co-encapsulate siRNA and doxorubicin (Dox) reveals a significantly enhanced anti-tumor effect for a multi-drug resistant tumor model.
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Portadores de Fármacos/síntesis química , Microfluídica/métodos , Nanopartículas/química , Antibióticos Antineoplásicos/administración & dosificación , Antibióticos Antineoplásicos/química , Simulación por Computador , Doxorrubicina/administración & dosificación , Doxorrubicina/química , Portadores de Fármacos/química , Composición de Medicamentos , Fluoresceínas/química , Interacciones Hidrofóbicas e Hidrofílicas , Indicadores y Reactivos , Ácido Láctico , Ácido Poliglicólico , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , ARN Interferente Pequeño/química , Rodaminas/química , Agua/químicaRESUMEN
The gene PGRMC1 is highly expressed in the granulose and luteal cells of rodent and primate ovaries. Its role in anti-apoptosis and regulating cell-cycle progression suggests a role in regulating follicle growth. The hypothesis is supported by the study in mice and studies in Sweden. In this study, the coding exons of PGRMC1 were sequenced among 196 Chinese women with premature ovarian failure (POF) and 200 controls, and one novel missense mutation was identified (C.556C>T, p. Pro186Ser) in the POF group and one novel SNP (C.533C>T, p. Trh177Ile) was identified in both groups. The mutation is not considered causative because protein prediction did not indicate a deleterious effect. It is concluded that coding mutations of PGRMC1 do not seem to be a common cause of the disease in Han Chinese women. Future studies in larger cohorts from other ethnic groups are necessary to establish the role of PGRMC1 in POF.
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Células de la Granulosa/metabolismo , Proteínas de la Membrana/genética , Mutación , Insuficiencia Ovárica Primaria/etnología , Insuficiencia Ovárica Primaria/genética , Receptores de Progesterona/genética , Adulto , Apoptosis , Pueblo Asiatico/genética , Estudios de Casos y Controles , Ciclo Celular , China , Codón , Estudios de Cohortes , Cartilla de ADN , Exones , Femenino , Hormona Folículo Estimulante/metabolismo , Predisposición Genética a la Enfermedad , Humanos , Mutación MissenseRESUMEN
Studying dendrimer-biomembrane interactions is important for understanding drug and gene delivery. In this study, coarse-grained molecular dynamics simulations were performed to investigate the behaviors of polyamidoamine (PAMAM) dendrimers (G4 and G5) as they interacted with asymmetric membranes from different sides of the bilayer, thus mimicking different dendrimer transport stages. The G4 dendrimer could insert into the membrane during an equilibrated state, and the G5 dendrimer could induce pore formation in the membrane when the dendrimers interacted with the outer side (outer interactions) of an asymmetric membrane [with 10% dipalmitoyl phosphatidylserine (DPPS) in the inner leaflet of the membrane]. During the interaction with the inner side of the asymmetric membrane (inner interactions), the G4 and G5 dendrimers only adsorbed onto the membrane. As the membrane asymmetry increased (e.g., increased DPPS percentage in the inner leaflet of the membrane), the G4 and G5 dendrimers penetrated deeper into the membrane during the outer interactions and the G4 and G5 dendrimers were adsorbed more tightly onto the membrane for the inner interactions. When the DPPS content reached 50%, the G4 dendrimer could completely penetrate through the membrane from the outer side to the inner side. Our study provides molecular understanding and reference information about different dendrimer transport stages during drug and gene delivery.
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Malaria, a mosquito-borne disease caused by Plasmodium species, causes substantial morbidity and mortality throughout the world. Plasmodium sporozoites mature in oocysts formed in the mosquito gut wall and then invade the salivary glands, where they remain until transmitted to the vertebrate host during a mosquito bite. The Plasmodium circumsporozoite protein (CSP) binds to salivary glands and plays a role in the invasion of this organ by sporozoites. We identified an Anopheles salivary gland protein, named CSP-binding protein (CSPBP), that interacts with CSP. Downregulation of CSPBP in mosquito salivary glands inhibited invasion by Plasmodium organisms. In vivo bioassays showed that mosquitoes that were fed blood with CSPBP antibody displayed a 25% and 90% reduction in the parasite load in infected salivary glands 14 and 18 days after the blood meal, respectively. These results suggest that CSPBP is important for the infection of the mosquito salivary gland by Plasmodium organisms and that blocking CSPBP can interfere with the Plasmodium life cycle.
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Anopheles/parasitología , Interacciones Huésped-Parásitos , Proteínas Protozoarias/metabolismo , Proteínas y Péptidos Salivales/metabolismo , Animales , Femenino , Humanos , Ratones , Plasmodium berghei/aislamiento & purificación , Unión Proteica , Glándulas Salivales/parasitologíaRESUMEN
OBJECTIVE: Endometrial cancer is one of the most common tumors of the female reproductive system, and the existing treatment options for advanced and metastatic endometrial cancer have certain limitations. The antitumor activity of luteolin has been gradually discovered. The purpose of this study was to predict the potential of luteolin in the treatment of endometrial cancer and to provide reference for future clinical drug use. METHODS: The target gene database of luteolin and differential gene dataset of uterine corpus endometrial carcinoma (UCEC) have been constructed to obtain the differential genes (DR-DEGs) for luteolin and UCEC. The Gene Set Enrichment Analysis (GSEA), Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis are performed at the same time. Genes associated with prognosis in DR-DEGs were screened and validated using univariate and multivariate COX risk regression analysis so as to construct a prognostic model. Genes are divided into high-risk and low-risk groups according to risk scores for survival analysis and the predictive effect of the model is evaluated. The role of immune function in UCEC is investigated by immune infiltration and immune checkpoint analysis Finally, Transwell experiment was conducted to investigate the effect of luteolin on the migration ability of endometrial cancer cells, and the expression changes of MMP1, IL-17 and VEGF were detected by q-PCR. RESULTS: Through the GO, KEGG and GSEA enrichment analysis, we have found a significant enrichment in "IL 17 signaling (IL-17) pathway", "oxidative stress response" and "HOMOLOGOUS_RECOMBINATION". Through multivariate COX risk regression analysis, four genes associated with the prognosis are harvested, including "PRSS1, MMP1, ERBB2 and NUF2" which belong to high-risk genes. Kaplan-Meier analysis shows that the survival rate in the high risk group is lower than that in the low risk group, and the receiver operating characteristic (ROC) curve reveals that the predictive effect of the model is good and stable (area under 1-year curve (AUC) 0.569, two-year AUC 0.628 and three-year AUC 0.653). Immune infiltration and immune checkpoint analysis suggest that "CD40", "T cells regulatory (Tregs)", "dendritic cells resting" and "dendritic cells activated" are correlated with survival and prognosis in UCEC patients. In in vitro experiments, we found that the migration ability of endometrial cancer cells was significantly reduced after luteolin treatment, and the expressions of MMP1, IL-17 and VEGF were all decreased. CONCLUSION: Through bioinformatic analysis, we found that luteolin could slow down the progression of UCEC by inhibiting the production of inflammatory mediators such as IL-17 and oxidative stress, and constructed genetic prognostic models associated with them: PRSS1, MMP1, ERBB2 and NUF2, respectively. In addition, we found that luteolin has an inhibitory effect on the migration of endometrial cancer cells and can reduce the expressions of MMP1, IL-17 and VEGF, thus easing the progression of endometrial cancer.
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Hepatocellular carcinoma (HCC) is a clinically and genetically heterogeneous disease. To better describe the clinical value of the main driver gene mutations of HCC, we analyzed the whole exome sequencing data of 125 patients, and combined with the mutation data in the public database, 14 main mutant genes were identified. And we explored the correlation between the main mutation genes and clinical features. Consistent with the results of previous data, we found that TP53 and LRP1B mutations were related to the prognosis of our patients by WES data analysis. And we further explored the associated characteristics of TP53 and LRP1B mutations. However, it is of great clinical significance to tailor a unique prediction method and treatment plan for HCC patients according to the mutation of TP53. For TP53 wild-type HCC patients, we proposed a prognostic risk model based on 11 genes for better predictive value. According to the median risk score of the model, HCC patients with wild-type TP53 were divided into high-risk and low-risk groups. We found significant transcriptome changes in the enrichment of metabolic-related pathways and immunological characteristics between the two groups, suggesting the predictability of HCC immunotherapy by using this model. Through the CMap database, we found that AM580 had potential therapeutic significance for high-risk TP53 wild-type HCC patients.
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Anti-PD-1 therapy has shown promising outcomes in the treatment of different types of cancer. It is of fundamental interest to analyze the efficacy of anti-PD-1 therapy in cancer patients infected with hepatitis B virus (HBV) since the comorbidity of HBV and cancer is widely documented. We designed a multicenter retrospective study to evaluate the efficacy of anti-PD-1 therapy on non-liver cancer patients infected with HBV. We found anti-PD-1 therapy achieved much better outcomes in HBV+ non-liver cancer patients than their HBV- counterparts. We performed single-cell RNA sequencing (scRNA-seq) on peripheral blood mononuclear cells (PBMCs) from esophageal squamous cell carcinoma (ESCC) patients. We found both cytotoxicity score of T cells and MHC score of B cells significantly increased after anti-PD-1 therapy in HBV+ ESCC patients. We also identified CX3CR1high TEFF, a subset of CD8+ TEFF, associated with better clinical outcome in HBV+ ESCC patients. Lastly, we found CD8+ TEFF from HBV+ ESCC patients showing higher fraction of Exhaustionhi T than their HBV- counterpart. In summary, anti-PD-1 therapy on HBV+ non-liver cancer patients is safe and achieves better outcomes than that on HBV- non-liver cancer patients, potentially because HBV+ patients had higher fraction of Exhaustionhi T, which made them more efficiently respond to anti-PD-1 therapy.
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N-7 methylguanine (m7G) is one of the most common RNA base modifications in post-transcriptional regulation, which participates in multiple processes such as transcription, mRNA splicing and translation during the mRNA life cycle. However, its expression and prognostic value in uterine corpus endometrial carcinoma (UCEC) have not been systematically studied. In this paper, the data such as gene expression profiles, clinical data of UCEC patients, somatic mutations and copy number variants (CNVs) are obtained from the cancer genome atlas (TCGA) and UCSC Xena. By analyzing the expression differences of m7G-related mRNA in UCEC and plotting the correlation network maps, a risk score model composed of four m7G-related mRNAs (NSUN2, NUDT3, LARP1 and NCBP3) is constructed using least absolute shrinkage and selection operator (LASSO), univariate and multivariate Cox regression in order to identify prognosis and immune response. The correlation of clinical prognosis is analyzed between the m7G-related mRNA and UCEC via Kaplan-Meier method, receiver operating characteristic (ROC) curve, principal component analysis (PCA), t-SNE, decision curve analysis (DCA) curve and nomogram etc. It is concluded that the high risk is significantly correlated with (P < 0.001) the poorer overall survival (OS) in patients with UCEC. It is one of the independent risk factors affecting the OS. Differentially expressed genes are identified by R software in the high and low risk groups. The functional analysis and pathway enrichment analysis have been performed. Single sample gene set enrichment analysis (ssGSEA), immune checkpoints, m6A-related genes, tumor mutation burden (TMB), stem cell correlation, tumor immune dysfunction and rejection (TIDE) scores and drug sensitivity are also used to study the risk model. In addition, we have obtained 3 genotypes based on consensus clustering, which are significantly related to (P < 0.001) the OS and progression-free survival (PFS). The deconvolution algorithm (CIBERSORT) is applied to calculate the proportion of 22 tumor infiltrating immune cells (TIC) in UCEC patients and the estimation algorithm (ESTIMATE) is applied to work out the number of immune and matrix components. In summary, m7G-related mRNA may become a potential biomarker for UCEC prognosis, which may promote UCEC occurrence and development by regulating cell cycles and immune cell infiltration. It is expected to become a potential therapeutic target of UECE.
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Carcinoma Endometrioide , Neoplasias Endometriales , Femenino , Humanos , Pronóstico , Neoplasias Endometriales/patología , Regulación Neoplásica de la Expresión Génica , Carcinoma Endometrioide/patología , ARN Mensajero/genética , ARN Mensajero/metabolismoRESUMEN
Necroptosis, a programmed form of necrotic cell death, plays critical regulatory roles in the progression and metastatic spread of cancers such as cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC). However, there are few articles systematically analyzing the necroptosis-related long non-coding RNAs (NRlncRNAs) correlated with CESC patients. Both RNA-sequencing and clinical data of CESC patients are downloaded from TCGA database in this study. Pearson correlation analysis, least absolute shrinkage, operator algorithm selection and Cox regression model are employed to screen and create a risk score model of eleven-NRlncRNAs (MIR100HG, LINC00996, SNHG30, LINC02688, HCG15, TUBA3FP, MIAT, DBH-AS1, ERICH6-AS1SCAT1, LINC01702) prognostic. Thereafter, a series of tests are carried out in sequence to evaluate the model for independent prognostic value. Gene set enrichment analytic paper, Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes pathway enrichment analytic paper make it clear that immune-related signaling pathways are very rich in the high-risk subgroup. Additionally, the prognostic risk score model is correlated to immune cell infiltration, potential immune checkpoint, immune function, immune micro-environmental and m6A-related gene. Mutation frequency in mutated genes and survival probability trend are higher in the low-risk subgroup in most of test cases when compared to the high-risk subgroup. This study constructs a renewed prognostic model of eleven-NRlncRNAs, which may make some contribution to accurately predicting the prognosis and the immune response from CESC patients, and improve the recognition of CESC patients and optimize customized treatment regimens to some extent.
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Adenocarcinoma , Carcinoma de Células Escamosas , ARN Largo no Codificante , Neoplasias del Cuello Uterino , Femenino , Humanos , Carcinoma de Células Escamosas/genética , Inmunidad , Necroptosis/genética , Pronóstico , ARN Largo no Codificante/genética , Neoplasias del Cuello Uterino/genéticaRESUMEN
The diffusion of monomerically thin nanorods in polymer melts is studied by molecular dynamics simulations. We focus on the systems where chains are long enough to screen the hydrodynamic interactions such that the diffusion coefficient D ⥠for the direction parallel to the rod decreases linearly with increasing rod length l. In unentangled polymers, the diffusion coefficient for the direction normal to the rod exhibits a crossover from D ⥠~ l -2 to D ⥠~ l -1 with increasing l, corresponding to a progressive coupling of nanorod motion to the polymers. Accordingly, the rotational diffusion coefficient D R ≈ D ⥠l -2 ~ l -4 and then D R ~ l -3 as l increases. In entangled polymers, D ⥠and D R are suppressed for l larger than the entanglement mesh size a. D ⥠~ l -3 and D R ~ l -5 for l sufficiently above a in agreement with de Gennes' rod reptation model.
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Euphorbia helioscopia L. which is called "Zeqi" in China, is a medicinal plant extensively distributed worldwide, especially in China, and has been widely used for decades to treat various diseases including edema, phlegm and cough, malaria, dysentery, scab, tuberculous fistula, osteomyelitis, and cancer. The present review aims to provide up-to-date information on E. helioscopia, including its traditional uses, phytochemistry, quality control, pharmacological research, toxicology, and human studies in exploring future scientific and therapeutic potentials in disease treatment. So far, a total of 173 terpenoids, as well as polyphenols, steroids, lipids, and volatile oils have been isolated and identified from E. helioscopia. Among them, diterpenoids and ï¬avonoids are the most important and abundant bioactive constituents. Modern pharmacological studies have demonstrated that E. helioscopia has outstanding bioactivities especially on antiproliferative and multidrug resistance modulating. Nevertheless, most of these studies were carried out in vitro. The quality control, metabolites identification, in-depth in-vivo studies as well as toxicology and human studies for the crude extracts and active components are still very limited. Consequently, more well-designed pre-clinical and clinical studies are required to justify their reported therapeutic potential.
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Euphorbia , Plantas Medicinales , China , Etnofarmacología , Fitoquímicos/farmacología , Fitoterapia , Extractos Vegetales/farmacologíaRESUMEN
A number of regions designated as RD1-RD16 (region of difference) and encompassing 129 open reading frames have been identified between Mycobacterium tuberculosis and Mycobacterium bovis on the one hand and Bacillus Calmette-Guérin on the other. Identification of T cell epitopes from this set of proteins may serve to define candidate antigens with potentials in specific diagnosis and development of new vaccines against TB. All possible nonameric peptide sequences from proteins of these M. tuberculosis specific regions were analyzed in silico for the ability to bind to 33 alleles of class I HLA. These results reveal that of all RD proteins, a significant number of these peptides are predicted to be high-affinity HLA binders (T (1/2) >or= 100 min), irrespective of the length of the protein, and 67% of the peptides predicted to bind are mono-allelic in their binding. Pathogen peptides that could behave as self- or partially self-peptides in the host were eliminated using a comparative study with the human proteome, thus the number of peptides for analysis was reduced. The predicted epitopes can be tested experimentally for their inclusion in a potential vaccine against tuberculosis and specific diagnosis.