检索结果-南通市图书馆

维普期刊数据库

Epigenetic and non-epigenetic mode of SiRT1 action during oocyte meiosis progression

在线全文

学校读者我要写书评

暂无评论

Journal of Animal Science and Biotechnology 2019年第4期10卷 895-906页

作者： Jan Nevoral Lukas Landsmann Miriam Stiavnicka Petr Hosek Jiri Moravec Sarka Prokesova Hedvika Rimnacova Eliska Koutna pavel Klein Kristyna Hoskova Tereza Zalmanova Tereza Fenclova Jaroslav Petr Milena Kralickova Biomedical Center Faculty of Medicine in PilsenCharles Universityalej Svobody 1655/7632300 PilsenCzech Republic Department of Histology and Embryology Faculty of Medicine in PilsenCharles UniversityKarlovarska 4830166 PilsenCzech Republic Faculty of Science Charles UniversityAlbertov 2038/612800 PragueCzech Republic Faculty of Agriculture Food and Natural ResourcesCzech University of Life Sciences in PragueKamycka 12916500 Praha-SuchdolCzech Republic institute of Animal Science Pratelstvi 815/10710400Prague 10-UhrinevesCzech Republic

Background: SiRT1 histone deacetylase acts on many epigenetic and non-epigenetic targets. it is thought that SiRT1 is involved in oocyte maturation;therefore, the importance of the ooplasmic SiRT1 pool for the further fate of mature oocytes has been strongly suggested. We hypothesised that SiRT1 plays the role of a signalling molecule in mature oocytes through selected epigenetic and non-epigenetic ***: We observed SiRT1 re-localisation in mature oocytes and its association with spindle *** mature oocytes, SiRT1 distribution shows a spindle-like pattern, and spindle-specific SiRT1 action decreasesα-tubulin acetylation. Based on the observation of the histone code in immature and mature oocytes, we suggest that SiRT1 is mostly predestined for an epigenetic mode of action in the germinal vesicles(GVs) of immature oocytes. Accordingly, BML-278-driven trimethylation of lysine K9 in histone H3 in mature oocytes is considered to be a result of GV epigenetic ***: Taken together, our observations point out the dual spatiotemporal SiRT1 action in oocytes,which can be readily switched from the epigenetic to non-epigenetic mode of action depending on the progress of meiosis.

关键词： Epigenetics Histone code in vitro maturation Oocyte SiRT1 Sirtuin 1

维普期刊数据库

Photoluminescence control by hyperbolic metamaterials and metasurfaces:a review

在线全文

学校读者我要写书评

暂无评论

Opto-Electronic Advances 2021年第8期4卷 30-56页

作者： Leonid Yu.Beliaev Osamu Takayama pavel N.Melentiev Andrei V.Lavrinenko DTU Fotonik-Department of Photonics Engineering Technical University of Denmark0rsteds Plads 343DK-2800 Kgs.LyngbyDenmark institute of Spectroscopy RAS Moscow 108840Russia Higher School of Economics National Research UniversityMoscow 101000Russia

Photolu min esce nee in clud ing fluoresce nee plays a great role in a wide variety of applicati ons from biomedical sensing and imag ing to optoelectr on ***,the enhan ceme nt and con trol of photolu min esce nee has imme nse impact on both fun dame ntal scie ntific research and aforeme nti oned applicati *** various nano phot tonic schemes and nanostructures to enhance the photoluminescence,we focus on a certain type of nanostructures,hyperbolic metamaterials(HMMs).HMMs are highly ani sotropic metamaterials,which produce intense localized electric ***,HMMs n aturally boost photolu min esce nee from dye molecules,qua ntum dots,n itroge n-vaca ncy cen ters in diam on ds,perovskites and tra nsiti on metal dichalcoge *** provide an overview of various con figuratio ns of HMMs,i nclud ing metal-dielectric multilayers,trenches,metallic nanowires,and cavity structures fabricated with the use of noble metals,transparent conductive oxides,and refractory metals as plasmonic *** also discuss lasing action realized with HMMs.

关键词： fluorescence metamaterials metasurfaces Purcell effect nanophotonics hyperbolic metamaterials

维普期刊数据库

The Effect of Resveratrol on Bone Status in Rats with Bile Duct Obstruction

在线全文

学校读者我要写书评

暂无评论

Open Journal of Endocrine and Metabolic Diseases 2013年第1期3卷 46-51页

作者： Helena Zivna Stanislav Micuda Eva Brcakova-Dolezelova pavel Zivny Department of Pharmacology Medical Faculty Charles University Hradec Kralove Czech Republic institute of Clinical Biochemistry and Diagnostics Medical Faculty Charles University and University Hospital Hradec Kralove Czech Republic Radioisotope Laboratories and Vivarium Medical Faculty Charles University Hradec Kralove Czech Republic

Objective: We studied the influence of bile duct obstruction (BDO) after 28 days on bone metabolism status and their modification by resveratrol in male Wistar rats. Methods: The rats were divided into 3 groups: Sham group with laparotomy and vehiculum application, group BDO—bile duct obstruction and vehiculum application, and group RBDO—bile duct obstruction and resveratrol application (10 mg/kg dose of resveratrol orally once daily). The bone mineral density (BMD;g/cm2) and body composition were measured by dual energy X-ray absorptiometry. The physiccal strenght of femur was examined by controlled break biomechanical testing. The osteocalcin, procollagen type i N-terminal propeptide (PiNP) and carboxy-terminal collagen crosslinks (CTX) were analysed by EiA in the bone tissue homogenate. Results: The total BMD was lower in group BDO (0.176 ± 0.005;p = 0.01) and R-BDO (0.181 ± 0.004;p = 0.052) vs Sham (0.209 ± 0.003). BMD of femur diaphysis in BDO group decreased significantly (p = 0.01) but not in R-BDO animals (p = 0.052). Body fat (g, median) was lower in BDO (19.0) and R-BDO (26.0) than in Sham (35.0). The force needed for fracture of femurs (N) significantly decreased in BDO (154 ± 6) and R-BDO (151 ± 13) vs Sham group (208 ± 7). The force needed for neck fracture decreased in BDO (105 ± 3) and R-BDO (115 ± 8) vs Sham (135 ± 9). The osteocalcin decrease in group R-BDO (2.9 ± 0.1) vs Sham (3.7 ± 0.4). Higher PiNP/CTX were in BDO (20 ± 5/0.49 ± 0.08) and R-BDO (30 ± 4/0.55 ± 0.07) vs Sham (16 ± 4/0.48 ± 0.11). Conclusions: Our findings suggest that subchronic bile duct obstruction decreased body fat quantity and BMD with decrease of bone rigidity. Resveratrol showed protective effect on liver injury and consequently positive influence on bone tissue.

关键词： Bone Metabolism Rat Resveratrol Bile Duct Obstruction

The Cyclization of Alkyl Side Chains of Naphthalenes:The GC/Potential Energies/FTiR Approach

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Analytical Chemistry 2014年第14期5卷 957-968页

作者： pavel Straka Miroslava Novotná Petr Buryan Olga Bicáková institute of Rock Structure and Mechanics v.v.i.Academy of Sciences of the Czech RepublicPragueCzech Republic institute of Chemical Technology PragueCzech Republic

Gas chromatographic measurements of the retention times of alkyl naphthalenes on packed columns with polar and non-polar stationary phases have proven that the logarithm of the relative retention time increases bi-linearly (not linearly) with the number of carbon atoms in a molecule. This is caused by a strong inclination of alkyl side chains toward intramolecular cyclization. A FTiR spectral analysis has shown that longer alkyl side chains of alkyl naphthalenes are cyclized through an interaction between the terminal CH3 group and the aromatic ring. Conventional aromatic-aliphatic molecules thus become new molecules with quasi-alicyclic rings. This, however, alters the effect of non-covalent van der Waals attractive forces both inside and outside the molecules, which is reflected in an exponential increase of the retention times of alkyl naphthalenes with a side chain longer than propyl and in the bi-linearity of the logarithmic dependence of the relative retention times on the number of carbons in the molecule.

关键词： Alkyl Naphtalenes Retention Times Molecular Mechanics van der Waals Forces

First Order Phase Transitions as Radiation Processes, Part Two

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Optics and Photonics Journal 2014年第2期4卷 26-37页

作者： Vitali A. Tatartchenko pavel V. Smirnov Hongrong Jin Shanghai CEC ZhenHua Crystal Technology Co. Ltd. Shanghai China

This paper presents new experimental results concerning the PeTa effect—infrared characteristic radiation under first order phase transitions, especially during deposition and condensation of vapours/gases and the crystallisation of melts. The abbreviation “PeTa effect” means Perel’man-Tatartchenko’s effect. The nature of the PeTa effect is transient radiation that a particle (i.e., atom, molecule or/and cluster) emits during a transition from a meta-stable higher energetic level (in a super-cooled melt or super-saturated vapour) to the stable condensed lower level (in a crystal or liquid). The radiation removes latent heat with photons of characteristic frequencies that are generated under this transition. This paper is the second in a set describing the appearance of PeTa radiation under air cooling with deposition and condensation of air components. The radiation was recorded using an iR Fourier Spectrometer with a highly sensitive MCT detector. Certain peculiarities of the recorded radiation as well as its applications in the physics of the atmospheres of Earth and Jupiter are analysed.

关键词： PeTa Effect First Order Phase Transitions Vapour Condensation Vapour Deposition Melt Crystallisation infrared Radiation Atmospheric Phenomena igloo Effect Jupiter

Antibody-Like Phosphorylation Sites in Focus of Statistically Based Bilingual Approach

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computational Molecular Bioscience 2016年第1期6卷 1-22页

作者： Jaroslav Kubrycht Karel Sigler pavel Souček Jiří Hudeček Department of Physiology Second Faculty of Medicine Charles University Prague Czech Republic Laboratory of Cellular Biology Institute of Microbiology Academy of Sciences of the Czech Republic Prague Czech Republic Toxicogenomics Unit National Institute of Public Health Prague Czech Republic Department of Biochemistry Charles University Prague Czech Republic

in accordance with previous reports, the sequences related to phosporylated protein segments occur in conserved variable domains of immunoglobulins including first of all certain N-terminally located segments. Consequently, we look here for the sequences 1) composing human and mouse proteins different from antigen receptors, 2) identical with or highly similar to nucleotide sequence representatives of conserved variable immunoglobulin segments and 3) identical with or closely related to phosphorylation sites. More precisely, we searched for the corresponding actual pairs of DNA and protein sequence segments using five-step bilingual approach employing among others a) different types of BLAST searches, b) two in-principle-different machine-learning methods predicting phosphorylated sites and c) two large databases recording existing phosphorylation sites. The approach identified seven existing phosphorylation sites and thirty-seven related human and mouse segments achieving limits for several predictions or phylogenic parameters. Mostly serines phosporylated with ataxia-telangiectasia-related kinase (involved in regulation of DNA-double-strand-break repair) were indicated or predicted in this study. Hypermutation motifs, located in effective positions of the selected sequence segments, occurred significantly less frequently in transcribed than non-transcribed DNA strands suggesting thus the incidence of mutation events. in addition, marked differences between the numbers and proportions of human and mouse cancer-related sequence items were found in different steps of selection process. The possible role of hypermutation changes within the selected segments and the observed structural relationships are discussed here with respect to DNA damage, carcinogenesis, cancer vaccination, ageing and evolution. Taken together, our data represent additional and sometimes perhaps complementary information to the existing databases of empirically proven phosphorylation sites or pa

关键词： Ataxia Telangiectasia-Mutated-Protein (i.e. Kinase ATM Whose Pathogenic Mutation is Responsible for Early Death of People) Complementarity Determining Region 1 (of immunoglobulins i.e. CDR1 or Hypervariable Region 1) Database (of Functional Structures) Hypermutation (i.e. Mutation of DNA Sequences Mediated by Enzymes) immunoglobulin (i.e. ig or Antibody) Phosphorylation (Enzyme Mediated Modification Concerns Here Mostly Protein Sequences)

First Order Phase Transitions as Radiation Processes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Optics and Photonics Journal 2013年第8期3卷 1-12页

作者： Vitali A. Tatartchenko pavel V. Smirnov Yong Wu Shanghai CEC Zhenhua Crystal Technology Co. Ltd. Shanghai China

This paper presents new experimental evidence of the PeTa effect—infrared characteristic radiation under first order phase transitions, especially the crystallization of melts and the deposition and condensation of vapours/gases. The PeTa effect describes the transient radiation that a particle (i.e., atom, molecule or/and cluster) emits transient radiation during a transition from a meta-stable higher energetic level (in a super-cooled melt or a super-saturated vapour) to the stable condensed lower level (in a crystal or a liquid). The radiation removes latent heat with photons of characteristic frequencies that are generated under this transition. The abbreviation “PeTa effect” means Perel’man-Tatartchenko’s effect.

关键词： Peta Effect First Order Phase Transitions Vapour Condensation Vapour Deposition Melt Crystallization infrared Radiation Atmospheric Phenomena

Secondary alteration of minerals in basalts of the Evevpenta gold occurrence(North Kamchatka， Russia) as indicators of ore forming processes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

地学前缘 2023年

作者： Anastasiya Sergeeva pavel Zhegunov Elena Skilskaia Mariya Nazarova Elena Kartasheva Anna Kuzmina Svetlana Moskaleva Olesya Zobenko Sharapat Kudaeva Ekaterina Plutakhina Kseniya Shishkanova institute of Volcanology and Seismology， Far Eastern Branch， Russian Academy of Sciences

This paper describes in detail the mineralogy of the propylitic alteration of basalt host rocks in the Evevpenta gold occurrence in North Kamchatka. The vein system of the Evevpenta consists of quartz， adularia-quartz， quartz-carbonate veins， and， hydrothermal breccias hosted in dacite. Vein minerals are native gold， tellurides， sulfides， selenides， Au-Ag chlorides. The propylitic alteration occurs at a distance from the epithermal veins; however， it contains characteristic mineral assemblages useful for the reconstruction of an ore-formation environment. Four distinct hydrothermal alteration assemblages were recognized within the propylitic zone in this study: (1) Fluorapatite-fluorine-aluminous titanite， (2) Quartz-calcite-clinochlore， (3) Quartz-calcite-stilbite-montmorillonite， and 4. Calcite-mordenite. The earliest mineral assemblage was formed from an acid F-enriched hydrothermal fluid. The concentration of fluoride in fluid was 0.2–1.2 g/L， and temperature of about 550 ℃. The long-term interaction between the acid hydrothermal fluid and olivine basalt host rocks resulted in increasing pH to near neutral that caused chloritization process. The chloritization stage hydrothermal fluid was enriched in Fe and Mg with temperatures of about 175–210℃， chlorite i， and 120–140℃， chlorite ii. The final stage of alteration consists of zeolite group minerals， which were precipitated from the hydrothermal fluid of pH ～ 9 and temperature >135℃. The high pH of the hydrothermal fluid could be explained by the presence of bicarbonates and carbonates and removal of the iron salt from the solution. Based on the alteration mineral assemblages of the propylitic zone， the physical and chemical conditions of the Evevpenta vein system are discussed. The transport of ore elements took place due to the formation of precious metal Cl–and OH–complexes at the stage of hydrothermal system formation with circulation of alkaline sodium chloride solutions. Chalcogens were also transferred by

关键词：

Different clinical presentations of metachronous pulmonary metastases after resection of pancreatic ductal adenocarcinoma: Retrospective study and review of the literature

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2017年第35期23卷 6420-6428页

作者： Martin Lovecek pavel Skalicky Josef Chudacek Marek Szkorupa Hana Svebisova Radmila Lemstrova Jiri Ehrmann Bohuslav Melichar Tharani Yogeswara Dusan Klos Radek Vrba Roman Havlik Beatrice Mohelnikova-Duchonova Department of Surgery i University Hospital Olomouc and Faculty of Medicine and DentistryPalacky University Department of Oncology University Hospital Olomouc and Faculty of Medicine and DentistryPalacky University Department of Molecular Pathology Faculty of Medicine and DentistryPalacky University OlomoucUniversity Hospital Olomouc institute of Molecular and Translational Medicine Faculty of Medicine and DentistryPalacky University Department of Oncology Faculty of Medicine and DentistryPalacky University OlomoucUniversity Hospital Olomouc Department of Surgery i Faculty of Medicine and DentistryPalacky University

AiM To analyze pancreatic cancer patients who developed metachronous pulmonary metastases(MPM) as a first site of recurrence after the curative-intent *** One-hundred-fifty-nine consecutive pancreatic ductal adenocarcinoma(PDAC) patients who underwent radical pancreatic surgery between 2006 and 2013 were included in this retrospective analysis. The clinical data including age, sex, grade, primary tumor location, p TNM stage, lymph node infiltration, microangioinvasion, perineural invasion, lymphovascular invasion, the therapy administered, and follow-up were all obtained from medical records. Further analysis covered only patients with metachronous metastases. Clinical and histopathological data(age, sex, grade, primary tumor location, p TNM stage, lymph node infiltration, microangioinvasion, perineural invasion, lymphovascular invasion, the therapy administered and follow-up) of patients with metachronous non-pulmonary metastases and patients with metachronous pulmonary metastases were statistically assessed. Disease-free survival(DFS) from pancreas resection until metastases onset and overall survival(OS) were calculated. Wilcoxon test, χ~2 test and survival functions computed by the KaplanMeier method were used. Statistical significance was evaluated by the log-rank test using SPSS. A P-value of less than 0.05 was considered statistically *** Metachronous pulmonary metastases were observed in 20(16.9%) and were operable in 3(2.5%) of PDAC patients after a prior curative-intent surgery. Patients with isolated pulmonary metastases(oligometastases and multiple metastases) had estimated prior DFS and OS of 35.4 and 81.4 mo, respectively, and those with metachronous pulmonary metastases accompanied by other metastases had prior DFS and OS of 17.3 and 23.4 mo, respectively. Patients with non-pulmonary metastases had prior DFS and OS of 9.4 and 15.8 mo, respectively. Different clinical scenarios according to the presentation of MPM were obser

关键词： Pancreatic cancer Pulmonary metastases Metachronous metastases Surgical resection Overall survival Chemotherapy