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Arrestins:structural disorder creates rich functionality

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Protein & Cell 2018年第12期9卷 986-1003页

作者： Vsevolod V.Gurevich Eugenia V.Gurevich vladimir n.uversky Department of Pharmacology Vanderbilt UniversityNashvilleTN 37232USA Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute Morsani College of Medicine University of South FloridaTampaFL 33612USA Institute for Biological Instrumentation Russian Academy of SciencesPushchinoMoscow RegionRussia 142290

Arrestins are soluble relatively small 44-46 kDa proteins that specifically bind hundreds of active phosphorylated GPCRs and dozens of non-receptor partners. There are binding partners that demonstrate preference for each of the known arrestin conformations: free, receptor-bound, and microtubule-bound. Recent evidence suggests that conformational flexibility in every functional state is the defining characteristic of arrestins. Flexibility, or plasticity, of proteins is often described as structural disorder, in contrast to the fixed conformational order observed in high-resolution crystal structures. However, protein-protein interactions often involve highly flexible elements that can assume many distinct conformations upon binding to different partners. Existing evidence suggests that arrestins are no exception to this rule: their flexibility is necessary for functional versatility. The data on arrestins and many other multi-functional proteins indicate that in many cases, "order" might be artificially imposed by highly non-physiological crystallization conditions and/or crystal packing forces. In contrast, conformational flexibility (and its extreme case, intrinsic disorder) is a more natural state of proteins, representing true biological order that underlies their physiologically relevant functions.

关键词： EPR GPCR nMR arrestin crystal structure disorder protein-protein interactions

High-level intrinsic disorder explains the universality of CLIP binding to diverse MHC class II variants

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Cellular & Molecular Immunology 2018年第1期15卷 76-78页

作者： vladimir n uversky Yaping n Tu Onyekachi nwogu Shanitra n Butler Michael Ramsamooj George Blanck Department of Molecular Medicine Morsani College of MedicineUniversity of South Floridaand Immunology ProgramTampaFLUSA H.Lee Moffitt Cancer Center and Research Institute TampaFLUSA

MHC class I and II molecules bind peptides that are either recognized as self or as foreign to the immune system via interaction with T-cell *** T-cell receptor makes molecular contacts with the peptide and the MHC molecule in the region of the MHC peptide binding *** MHC class I and II molecules are highly polymorphic,which presumably allows for great diversity of antigen-binding sites over the population,leading to a species that is relatively fit to withstand foreign *** MHC class I molecules,this allelic variation predicts extensive variation in the sequence of peptides able to bind MHC class I molecules,and this is indeed the case.

关键词： explain class intrinsic

Study of asphaltene reaggregation in toluene/heptane mixture by dynamic and static light scattering

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Petroleum Research 2024年第1期9卷 48-54页

作者： vladimir n.Kuryakov Oil and Gas Research Institute of RAS(OGRI RAS) Gubkina Str.3119333MoscowRussian Federation

This paper presents the study of the effect of multiple ultrasonic impacts on submicron asphaltene aggregates in a toluene/heptane solution,conducted with dynamic light scattering *** objects of the study were four samples of asphaltenes obtained from four different *** all samples,the change in the average size of the asphaltene submicron aggregates with time was measured after the addition of a precipitant(heptane)to a solution of asphaltenes in toluene at an amount above the threshold *** aggregates formed in solution after the addition of the precipitant and were subjected to ultrasonic treatment,which led to the destruction of the asphaltene *** of destroyed asphaltenes was *** kinetics of this aggregation were similar to the kinetics of aggregation of asphaltenes after the addition of a *** iterations of asphaltene aggregate destruction in the sample led to a significant change in the kinetics of aggregation:the growth of aggregates slowed and stabilized at a size of approximately 200 nm and 30 nm for the different studied samples.

关键词： Asphaltenes Aggregation Sonication Dynamic light scattering Re-aggregation Colloidal stability Resins

Inversion of walkaway VSP data in the presence of lateral velocity heterogeneity

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Energy Geoscience

Energy Geoscience 2024年第2期5卷 304-313页

作者： vladimir Grechka Ilya Tsvankin Pedro Contreras CWP Department of GeophysicsColorado School of MinesGoldenCO80401USA PDVSA-InTEVEP Apartado 76343Caracas1070AVenezuela Borehole Seismic LLC USA Department of Physics ULAVenezuela

Multi-azimuth walkaway vertical seismic profiling is an established technique for the estimation of in situ slowness surfaces and inferring anisotropy ***,this technique requires the assumption of lateral homogeneity,which makes the horizontal slowness components at depths of downhole receivers equal to those measured at the *** violations of this assumption,such as lateral heterogeneity or nonzero dip of intermediate interfaces,lead to distortions in reconstructed slowness surfaces and,consequently,to errors in estimated anisotropic *** this work,we relax the assumption of lateral homogeneity and discuss how to correct vertical seismic profile data for weak lateral *** describe a procedure of downward continuation of recorded traveltimes that accounts for the presence of both vertical inhomogeneity and weak lateral heterogeneity,which produces correct slowness surfaces at depths of downhole receivers,noticing that sufficiently dense receiver coverage along a borehole is required to separate influences of vertical and lateral heterogeneity on measured traveltimes and obtain accurate estimates of the slowness *** the slowness surfaces are found and a desired type of anisotropic model to be inverted is selected,the corresponding anisotropic parameters,providing the best fit to the estimated slownesses,can be *** invert the slowness surfaces of P-waves for parameters of the simplest anisotropic model describing dipping fractures(transversely isotropic medium with a tilted symmetry axis).Five parameters of this model,namely,the P-wave velocity V0 in the direction of the symmetry axis,Thomsen's anisotropic coefficients e and d,the tilt n,and the azimuth b of the symmetry axis,can be estimated in a stable manner when maximum source offset is greater than half of receiver depth.

关键词： Walkaway vertical seismic profile Lateral velocity heterogeneity Anisotropic parameter estimation Vertical inhomogeneity

Morphological and biochemical characteristics associated with autophagy in gastrointestinal diseases

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World Journal of Gastroenterology 2024年第11期30卷 1524-1532页

作者： Yi-Fan Chang Jia-Jing Li Tao Liu Chong-Qing Wei Li-Wei Ma vladimir n nikolenko Wei-Long Chang Department of Gastrointestinal Surgery The First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052Henan ProvinceChina Department of Pathology The First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052Henan ProvinceChina Department of Clinical Laboratory The First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052Henan ProvinceChina Department of Human Anatomy and Histology I.M.Sechenov First Moscow State Medical University(Sechenov University)Moscow 119991Russia

Autophagy is a cellular catabolic process characterized by the formation of double-membrane *** electron microscopy is the most rigorous method to clearly visualize autophagic engulfment and degradation.A large number of studies have shown that autophagy is closely related to the digestion,secretion,and regeneration of gastrointestinal(GI)***,the role of autophagy in GI diseases remains *** article focuses on the morphological and biochemical characteristics of autophagy in GI diseases,in order to provide new ideas for their diagnosis and treatment.

关键词： Autophagy Morphological study Biochemical characteristics Subcellular structure Transmission electron microscopy Gastrointestinal diseases

Green synthesis of biocompatible Gd^(3+)-doped ultrasmall carbon-based nanohybrids from coffee wastes

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Carbon Resources Conversion 2024年第2期7卷 64-73页

作者： Konstantin Paliienko Anna Topchylo Sergei Alekseev Alain Géloën Yurii Milovanov Tetiana Lysenko Valeriy Skryshevsky Tatiana Borisova vladimir Lysenko Department of neurochemistry Palladin Institute of BiochemistryNational Academy of Sciences of Ukraine9 Leontovicha strKyiv 01054Ukraine Corporation Science Park Taras Shevchenko University of Kyiv60 Volodymyrska Str.Kyiv 01033Ukraine Institute of High Technologies Taras Shevchenko National University of Kyiv64 Volodymyrska Str.01601 KyivUkraine Faculty of Chemistry Taras Shevchenko National University of Kyiv64 Volodymyrska Str.01601 KyivUkraine UMR Ecologie Microbienne Lyon(LEM) CNRS 5557INRAE 1418Claude Bernard University of LyonVetAgro SupResearch Team“Bacterial Opportunistic Pathogens and Environment”(BPOE)University of LyonF-69622 VilleurbanneFrance Light Matter Institute UMR-5306Claude Bernard University of Lyon/CNRSUniversitéde Lyon69622 Villeurbanne CedexFrance

A cheap method allowing fabrication of biocompatible,ultra-small(2-10 nm)and fluorescent(λ_(em)=425-500 nm)nanohybrids(nHs)from coffee wastes is *** gadolinium-doped nanohybrids(GDnHs)or gadolinium-free carbon dots(GFCDs)can be synthesized in a domestic microwave oven according to green synthesis *** sizes,chemical composition,impact on proton magnetic resonance relaxation time and optical properties of the GDnHs and GFCDs were studied in details and *** particular,doping of the nHs with Gd^(3+)ions,up to 1.87%w/w of gadolinium per particles’weight,will allow their application for magnetic resonance imaging(MRI).Furthermore,cell culture tests on human adenocarcinomic alveolar basal epithelial cells line(A549)have shown high biocompatibility of the GDnHs and in a wide concentration range 100-1000μg/ml.

关键词： Carbon dots from coffee waste Carbon dots for MRI Gadolinium-doped carbon dots Microwave-assisted synthesis

Ferroelectricity Induced by Oxygen Vacancies in Rhombohedral ZrO_(2) Thin Films

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Energy & Environmental Materials 2024年第1期7卷 229-237页

作者： Veniero Lenzi José P.B.Silva Břetislav Šmíd vladimir Matoín Cosmin M.Istrate Corneliu Ghica Judith L.MacManus-Driscoll Luís Marques Physics Center of Minho and Porto Universities(CF-UM-UP) University of MinhoCampus de Gualtar 4710-057Braga Portugal Laboratory of Physics for Materials and Emergent Technologies LapMETUniversity of Minho4710-057Braga Portugal Department of Surface and Plasma Science Faculty of Mathematics and PhysicsCharles UniversityV Holešovičkách 218000Prague 8 Czech Republic national Institute of Materials Physics 105 bis Atomistilor 077125Magurele Romania Department of Materials Science and Metallurgy 27 Charles Babbage Rd.Cambridge CB3 OFSUK

Rhombohedral phase Hf_(x)Zr_(1.x)O_(2)(HZO,x from 0 to 1)films are promising for achieving robust ferroelectric polarization without the need for an initial wake-up pre-cycling,as is normally the case for the more commonly studied orthorhombic ***,a large spontaneous polarization observed in rhombohedral films is not fully understood,and there are also large discrepancies between experimental and theoretical *** this work,in rhombohedral ZrO_(2)thin films,we show that oxygen vacancies are not only a key factor for stabilizing the phase,but they are also a source of ferroelectric polarization in the *** is shown experimentally through the investigation of the structural properties,chemical composition and the ferroelectric properties of the films before and after an annealing at moderate temperature(400℃)in an oxygen environment to reduce the V_(o)concentration *** experimental work is supported by density functional theory(DFT)calculations which show that the rhombohedral phase is the most stable one in highly oxygen defective ZrO_(2)*** DFT calculations also show that V_(o)contribute to the ferroelectric *** findings reveal the importance of V_(o)for stabilizing rhombohedral ZrO_(2)thin films with superior ferroelectric properties.

关键词： charged defects ferroelectric polarization rhombohedral phase stability zirconia

Telluric iron assemblages as a source of prebiotic phosphorus on the early Earth:Insights from Disko Island,Greenland

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Geoscience Frontiers 2024年第5期15卷 415-429页

作者： Oleg S.Vereshchagin Maya O.Khmelnitskaya Larisa V.Kamaeva natalia S.Vlasenko Dmitrii V.Pankin vladimir n.Bocharova Sergey n.Britvin Saint Petersburg State University University Embankment 7-9St.Petersburg 199034Russia Udmurt Federal Research Center Ural BranchRussian Academy of SciencesIzhevsk 426067Russia nanomaterial Research Center Kola Science CentreRussian Academy of SciencesApatity 184209Russia

Phosphorus is one of the key elements,which determined the emergence of primordial life on our *** source of prebiotic phosphorus was most likely to be easily soluble compounds containing phosphorus in the negative form of oxidation(e.g.,phosphides).The present paper is the first thorough investigation of phosphide-bearing mineral assemblages confined to telluric(terrestrial)native iron from volcanic rocks of Disko Island,*** speciation in given assemblages varies from the solid solution in native iron(up to 0.3 wt.%P),different phosphides–schreibersite Fe_(3)P,nickelphosphide ni_(3)P,barringerite Fe_(2)P,and phosphates,including fluorapatite,anhydrous Fe-na phosphates,phosphoran olivine and pyroxene(up to 1 wt.%P).The diversity of observed phosphorus speciation can be explained by the steep changes of redox conditions during subsurface crystallization of iron-phosphide-bearing *** on the available data on likely redox conditions on the early Earth,we hypothesize that reactive prebiotic phosphorus may have originated from shallow crustal rocks.

关键词： Prebiotic phosphorus native iron Phosphide Reduced mineral assemblages

Superior piezoelectric performance with high operating temperature in bismuth ferrite-based ternary ceramics

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Journal of Materials Science & Technology 2024年第2期169卷 172-181页

作者： Yunyao Huang Leiyang Zhang Ruiyi Jing Yang Yang vladimir Shur Xiaoyong Wei Li Jin Electronic Materials Research Laboratory Key Laboratory of the Ministry of EducationSchool of Electronic Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China Faculty of Materials and Manufacturing Key Laboratory of Advanced Functional MaterialsEducation Ministry of ChinaBeijing University of TechnologyBeijing 100124China School of natural Sciences and Mathematics Ural Federal UniversityEkaterinburg620000Russia

Due to the thermal depolarization effect,adequate piezoelectric performance with high operating temperature is regarded to be challenging to accomplish concurrently in piezoceramics for applications in specific piezoelectric *** this work,we synthesized(0.8−x)BiFeO_(3)-x PbTi_(3)-0.2Ba(Zr_(0.25)Ti_(0.75))O_(3)(abbreviated as BFO-x PT-BZT)ternary solid solutions with 0.15≤x≤0.30 by conventional solid-state reaction *** MPB composition with a coexisting state of rhombohedral-tetragonal phases exhibits enhanced electromechanical properties,including Curie temperature of 380℃,large-signal equivalent piezoelectric coefficient d^(∗)_(33)of 395 pm V^(-1),small-signal piezoelectric coefficient d_(33)of 302 pC n^(-1),and electromechanical coupling factor k_(p)of 50.2%,which is comparable to commercial PZT-5A ceramics,indicating potential in high-temperature ***,in-situ X-ray diffraction(XRD)and piezoelectric force microscopic(PFM)techniques demonstrate that multiphase coexistence and complex nanodomains promote piezoelectric response via *** x=0.24 composition exhibits the highest in-situ d_(33)of 577 pC n^(-1)and good temperature stability in 30−280℃,indicating that BZT-modified BFO-PT ceramics are promising candidates for high-temperature piezoelectric devices.

关键词： High-temperature piezoelectrics Morphotropic phase boundary In-situ technique Domain structure BFO