11,429 results on '"Dynamics (mechanics)"'
Search Results
102. A genetically encoded sensor for measuring serotonin dynamics
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Mimi Shin, Xuelin Li, J. Julius Zhu, Peng Zhang, Jiesi Feng, Wanling Peng, Suyu Hao, Miao Jing, Jing Zou, B. Jill Venton, Tongrui Qian, Jianzhi Zeng, Fei Deng, Yulong Li, Sunlei Pan, Jinxia Wan, Kun Song, Min Xu, and Yajun Zhang
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Male ,0301 basic medicine ,Serotonin ,High selectivity ,Article ,Receptors, G-Protein-Coupled ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Animals ,Humans ,Receptor ,G protein-coupled receptor ,Neurons ,Chemistry ,General Neuroscience ,Dynamics (mechanics) ,HEK 293 cells ,Serotonin metabolism ,Rats ,HEK293 Cells ,030104 developmental biology ,Monoamine neurotransmitter ,Female ,Neuroscience ,030217 neurology & neurosurgery ,Serotonergic Neurons ,Signal Transduction - Abstract
Serotonin (5-HT) is a phylogenetically conserved monoamine neurotransmitter modulating important processes in the brain. To directly visualize the release of 5-HT, we developed a genetically encoded G-protein-coupled receptor (GPCR)-activation-based 5-HT (GRAB5-HT) sensor with high sensitivity, high selectivity, subsecond kinetics and subcellular resolution. GRAB5-HT detects 5-HT release in multiple physiological and pathological conditions in both flies and mice and provides new insights into the dynamics and mechanisms of 5-HT signaling.
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- 2021
103. Correlation of N-glycan dynamics and interaction network with allosteric antigen binding and Fc receptor recognition
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Buyong Ma
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0301 basic medicine ,Glycan ,Allosteric regulation ,Cancer therapy ,Fc receptor ,allosteric ,03 medical and health sciences ,0302 clinical medicine ,Interaction network ,glycan ,biology ,Chemistry ,Dynamics (mechanics) ,Tumor therapy ,molecular dynamics simulations ,RC581-607 ,Antigen binding ,Cell biology ,antigen recognition ,carbohydrates (lipids) ,030104 developmental biology ,030220 oncology & carcinogenesis ,biology.protein ,fc receptor binding ,antibody drug ,Immunologic diseases. Allergy - Abstract
Aim: Fragment crystallizable (Fc) glycans modulate Fc conformations and functions, and glycan may also regulate antigen recognition. In the antibody drug development, glycosylation patterns affect antibody drug characteristics and quality control. In order to provide a global feature of N-glycan interactions in response to antigen and Fc receptor bindings, the interactions among Fc N-glycans and N-glycans’ interaction with Fc CH2 and CH3 domains have been studied. Methods: Molecular dynamics simulations were used to generate conformation ensembles of free antibody, antibody-antigen complex, antibody-human Fc-gamma-receptor-I (hFcγRI) and antibody-antigen-hFcγRI, the hydrogen bonds and radial distance distribution involving N-glycans carbohydrate chains have been analyzed. Results: Two important interaction patterns have been observed. The first is the strong but non-specific interactions between two carbohydrate chains in free antibody. Secondly, it has been found that N-glycans carbohydrate chains can directly interact with CH3 domain in free antibody, and that the distance distribution between carbohydrate chains and CH3 domain clearly differentiate the free antibody, antibody-antigen complex, antibody-hFcγRI complex, and final antibody-antigen-hFcγRI complex. Conclusions: N-glycans partially acts as allosteric sensor and respond to antigen and hFcγRI binding.
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- 2021
104. The Role of Shaking of a Liquid Sample in the Dynamics of Polymer Membrane Swelling: A Cell of Limited Volume
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M. S. Kir’yanova, N. F. Bunkin, M. T. Vu, T. Yu. Komkova, R. S. Safronenkov, V. A. Kozlov, and P. N. Bolotskova
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chemistry.chemical_classification ,Materials science ,Dynamics (mechanics) ,Cell ,General Physics and Astronomy ,Infrared spectroscopy ,Polymer ,chemistry.chemical_compound ,medicine.anatomical_structure ,Membrane ,chemistry ,Volume (thermodynamics) ,Chemical engineering ,Nafion ,medicine ,Swelling ,medicine.symptom - Abstract
The swelling of a Nafion polymer membrane in water poured into a cell with a characteristic size close to the membrane thickness has been studied experimentally using Fourier IR spectroscopy. The interest in these studies is due to the fact that the Nafion swelling in a cell whose size greatly exceeds the membrane thickness is accompanied by intense unwinding of polymer fibers into the water bulk. However, this process had not been studied in the case where the region that can be occupied by unwound polymer fibers is limited by the cell size. It is shown that the temporal dynamics of the polymer transition from hydrophobic to hydrophilic state has some peculiar features in this case, which are determined by the cell size, isotopic composition, and preliminary treatment (intense shaking) of the liquid in which a Nafion sample swells.
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- 2021
105. Dynamics of a Q-switched bismuth-doped fibre laser: simulation and comparison with experiment
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D. E. Artemov, A. I. Fedoseev, Oleg E Nanii, and Alexander Smirnov
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Materials science ,business.industry ,Dynamics (mechanics) ,Doping ,chemistry.chemical_element ,Statistical and Nonlinear Physics ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Bismuth ,chemistry ,Fiber laser ,Optoelectronics ,Electrical and Electronic Engineering ,business - Abstract
Using an improved travelling wave model, we have numerically investigated the dynamics of a Q-switched bismuth-doped fibre laser. Comparison of simulation results with previously reported experimental data demonstrates good agreement of the multipeak lasing structure and the shape of the strongest pulses at various levels of pumping. We have assessed the effect of the main laser parameters on output laser characteristics and quantitatively evaluated the effects of the nonsaturable loss in the active fibre and amplified spontaneous emission on output power saturation. Based on analysis of time-dependent light intensity and gain distributions in the gain medium at different instants in time, we have formulated recommendations how to improve output laser characteristics.
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- 2021
106. The vacuole controls nucleolar dynamics and micronucleophagy via the NVJ
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Most Naoshia Tasnin, Takashi Ushimaru, Tasnuva Sharmin, Shamsul Morshed, and Tsuneyuki Takuma
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0301 basic medicine ,Saccharomyces cerevisiae Proteins ,Biophysics ,Autophagy-Related Proteins ,Receptors, Cytoplasmic and Nuclear ,Saccharomyces cerevisiae ,Vacuole ,Mechanistic Target of Rapamycin Complex 1 ,DNA, Ribosomal ,Biochemistry ,03 medical and health sciences ,0302 clinical medicine ,Protein purification ,medicine ,Receptor ,Molecular Biology ,Ribosomal DNA ,Cell Nucleus ,Microbial Viability ,Chemistry ,Dynamics (mechanics) ,Nuclear Proteins ,Cell Biology ,Nutrient starvation ,Cell biology ,030104 developmental biology ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Vacuoles ,RDNA condensation ,Nucleus ,Cell Nucleolus ,Protein Binding - Abstract
Chromosomes have their own territories and dynamically translocate in response to internal and external cues. However, whether and how territories and the relocation of chromosomes are controlled by other intracellular organelles remains unknown. Upon nutrient starvation and target of rapamycin complex 1 (TORC1) inactivation, micronucleophagy, which preferentially degrades nucleolar proteins, occurs at the nucleus-vacuole junction (NVJ) in budding yeast. Ribosomal DNA (rDNA) is condensed and relocated against the NVJ, whereas nucleolar proteins move towards the NVJ for micronucleophagic degradation, causing dissociation of nucleolar proteins from rDNA. These findings imply that the NVJ is the critical platform in the directional movements of rDNA and nucleolar proteins. Here, we show that cells lacking the NVJ (NVJΔ cells) largely lost rDNA condensation and rDNA-nucleolar protein separation after TORC1 inactivation. The macronucleophagy receptor Atg39, an outer nuclear membrane protein, accumulated at the NVJ and was degraded by micronucleophagy. These suggested that macronucleophagy is also dependent on the presence of the NVJ. However, micronucleophagy, but not macronucleophagy, was abolished in NVJΔ cells. This study clearly demonstrated that vacuoles controls intranuclear events, nucleolar dynamics, from outside of the nucleus via the NVJ under the control of TORC1.
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- 2021
107. Protein structure, dynamics, and function—a 20th IUPAB Congress symposium
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Richard Charles Garratt
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Protein structure ,Structural Biology ,Chemistry ,Dynamics (mechanics) ,Commentary ,Biophysics ,Function (mathematics) ,Statistical physics ,Molecular Biology - Abstract
A wide range of topics was raised by the four invited speakers who took part in the session on protein structure, dynamics, and function during the 20th IUPAB Congress. Most of the emphasis was placed on understanding the underlying biological phenomena of interest although applications in drug development were also mentioned. For both these purposes, it was clear that a complete description of the dynamics of the system was as important as the structures themselves. The subjects covered included antibiotic peptides, sodium channels, the synthesis of the bacterial cell wall, and protein dynamics using X-FELs.
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- 2021
108. Brush-Like Polymers and Entanglements: From Linear Chains to Filaments
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Heyi Liang, Gary S. Grest, and Andrey V. Dobrynin
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chemistry.chemical_classification ,Quantitative Biology::Biomolecules ,Materials science ,Polymers and Plastics ,Polymer science ,Organic Chemistry ,Dynamics (mechanics) ,Brush ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,High molecular weight polymer ,0104 chemical sciences ,law.invention ,Condensed Matter::Soft Condensed Matter ,Inorganic Chemistry ,chemistry ,Chain (algebraic topology) ,law ,Materials Chemistry ,0210 nano-technology - Abstract
Dynamics of melts and solutions of high molecular weight polymers and biopolymers is controlled by topological constraints (entanglements) imposing a sliding chain motion along an effective confining tube. For linear chains, the tube size is determined by universal packing number
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- 2022
109. How Tethered Probes Report the Dynamics of a Polymer near the Glass Transition
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Yae Eun Lee, Jisu Kim, Jongwon Choe, Yura Chung, Myungwoong Kim, Soo Hyun Lee, Keewook Paeng, and Ji Won Choi
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chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Tethering ,Organic Chemistry ,Dynamics (mechanics) ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,chemistry ,Chemical physics ,Materials Chemistry ,0210 nano-technology ,Glass transition - Abstract
How tethered probes report dynamics of host polymers near the glass transition was investigated by changing the length of the flexible linkers and the number of tethering points via imaging rotational fluorescence correlation microscopy and compared with free probes of different sizes. The results show that tethering did not alter the temperature-dependence of polymer dynamics and the shape of the correlation decay reported by the probe; however, the rotation slowed down up to ≈1 decade when both ends of the probe were restricted with short alkyl chain linkers. Upon comparison with the bigger free probe, the mechanism of the slowdown was attributed to the restricted motion upon tethering for tethered probes compared to averaging over different regions of the dynamic heterogeneity for the bigger probe. If the size of the probe was comparable to that of the dynamic heterogeneity of the system, tethered probes accurately report dynamics relevant to glass transition, regardless of tethering conditions.
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- 2022
110. Dynamics Gradient of Polymer Chains near a Solid Interface
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Daisuke Kawaguchi, Shin Sugimoto, Hung K. Nguyen, Keiji Tanaka, Manabu Inutsuka, and Asuka Konomi
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Imagination ,Materials science ,Chemical substance ,Polymers and Plastics ,Nitrile ,media_common.quotation_subject ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,Natural rubber ,Materials Chemistry ,media_common ,chemistry.chemical_classification ,Organic Chemistry ,Dynamics (mechanics) ,Relaxation (NMR) ,Polymer ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Chemical physics ,visual_art ,visual_art.visual_art_medium ,0210 nano-technology ,Science, technology and society - Abstract
The relaxation dynamics of polyisoprene (PI) and nitrile butadiene rubber (NBR) chains at the SiO2 interface were directly probed as a function of distance from the SiO2 surface using time-resolved...
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- 2022
111. Optical Autocatalysis Establishes Novel Spatial Dynamics in Phase Separation of Polymer Blends during Photocuring
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Saeid Biria, Tara F. Kahan, Phillip P A Malley, and Ian D. Hosein
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chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Spinodal decomposition ,Organic Chemistry ,Dynamics (mechanics) ,Nanotechnology ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Protein filament ,Autocatalysis ,Nonlinear system ,chemistry ,Chemical physics ,Materials Chemistry ,Polymer blend ,0210 nano-technology ,Microscale chemistry - Abstract
We report a fundamentally new nonlinear dynamic system that couples optical autocatalytic behavior to phase evolution in photoreactive binary polymer blends. Upon exposure to light, the blend undergoes spontaneous patterning into a dense arrangement of microscale polymer filaments. The filaments’ growth in turn induces local spinodal decomposition of the blend along their length, thereby regulating the spatially dynamics of phase separation. This leads to the spontaneous organization of a large-scale binary phase morphology dictated by the filament arrangement. This is a new mechanism for polymer blend organization, which couples nonlinear optical dynamics to chemical phase separation dynamics, and offers a new approach to light-directed patterning and organization of polymer and hybrid blends.
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- 2022
112. Impact of Interaction Strength and Surface Heterogeneity on the Dynamics of Adsorbed Polymers
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Guido Raos and Julien Idé
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Surface (mathematics) ,chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Diffusion ,Organic Chemistry ,Dynamics (mechanics) ,Activation energy ,Polymer ,Adhesion ,Condensed Matter::Soft Condensed Matter ,Inorganic Chemistry ,Molecular dynamics ,Adsorption ,chemistry ,Chemical physics ,Materials Chemistry - Abstract
We present molecular dynamics simulations of bead-and-spring polymer chains on chemically heterogeneous, energetically disordered surfaces at near-monolayer coverages. The surfaces consist of random mixtures of weakly (W) and strongly (S) attractive sites. We explore systematically the effect of surface composition on the diffusive dynamics of the chains. The polymer diffusion coefficients have a near-Arrhenius temperature dependence, with activation energies which have a nonmonotonic dependence on the fraction of S sites. In other words, we see a nonmonotonic dependence of the interfacial polymer dynamics on its affinity with the surface, when the latter involves some heterogeneity. The maximum activation energy belongs to the surface containing 75% S and 25% W sites, which combines near-maximum average polymer-surface interactions with near-maximum spread or disorder in these interactions. Our results have interesting implications for polymer adhesion and friction and structure-property relationships in polymer nanocomposites.
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- 2022
113. Insight into Shared Properties and Differential Dynamics and Specificity of Secretory Phospholipase A2 Family Members
- Author
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Zhongjie Han, Weikang Gong, Shan Zhang, Chunhua Li, and Yang Liu
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Cell signaling ,010304 chemical physics ,Chemistry ,Dynamics (mechanics) ,Allosteric regulation ,Computational biology ,010402 general chemistry ,01 natural sciences ,Secretory Phospholipase A2 ,0104 chemical sciences ,Surfaces, Coatings and Films ,Folding (chemistry) ,0103 physical sciences ,Materials Chemistry ,Physical and Theoretical Chemistry ,Signal transduction ,Differential (mathematics) ,Function (biology) - Abstract
Understanding generic mechanisms of functions shared by the secretory phospholipase A2 (sPLA2) family involved in the lipid metabolism and cell signaling and the molecular basis of function specificity for family members is an intriguing but challenging problem for biologists. Here, we explore the issue through extensive analyses using a combination of structure-based methods and bioinformatics tools on130 sPLA2 family members. The principal component analysis of the structure ensemble reveals that the enzyme has an open-close motion which helps widen the substrate binding channel, facilitating its binding to phospholipid. Performing elastic network model and sequence analyses found that the residues critical for family functions, such as cysteine and catalytic residues, are highly conserved and undergo minimal movements, which is evolutionarily essential as their perturbation would impact the function, while the four residue regions involved in the association with the calcium ion/membrane are lowly conserved and of high mobility and large variations in low-to-intermediate frequency modes, which reflects the specificity of members. The analyses from perturbation response scanning also reveal that the above four regions with high sensitivity to an external perturbation are member-specific, suggesting their different roles in allosteric modulation, while the minimal sensitive residues are the shared characteristics across family members, which play an important role in maintaining structural stability as the folding core. This study is helpful for understanding how sequences, structures, and dynamics of sPLA2 family members evolve to ensure their common and specific functions and can provide a guide for accurate design of proteins with finely tuned activities.
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- 2021
114. Dynamics of electron transfer in melanin-trinitrofluorenone system
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Petro Lutsyk, A. B. Verbitsky, Aleksey Rozhin, A. O. Kostetskyi, and Yu. P. Piryatinski
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chemistry.chemical_classification ,Photoluminescence ,Materials science ,Dynamics (mechanics) ,Kinetics ,General Chemistry ,Electron acceptor ,Condensed Matter Physics ,Photochemistry ,Melanin ,Electron transfer ,chemistry ,General Materials Science ,Emission spectrum - Abstract
The kinetics of photoluminescence (PL) and time-resolved emission spectra (TRES) of melanin solutions with an effective electron acceptor 2,4,7-trinitrofluorenone (TNF) have been studied. Based on ...
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- 2021
115. Cellulose Nanocrystal Laden Oil–Water Interfaces: Interfacial Viscoelasticity, Emulsion Stability, and the Dynamics of Three-Phase Contact-Lines
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Parisa Bazazi and S. Hossein Hejazi
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Materials science ,General Chemical Engineering ,Dynamics (mechanics) ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Industrial and Manufacturing Engineering ,Viscoelasticity ,Cellulose nanocrystals ,chemistry.chemical_compound ,020401 chemical engineering ,Three-phase ,chemistry ,Chemical engineering ,Nanocrystal ,Emulsion ,Oil water ,0204 chemical engineering ,Cellulose ,0210 nano-technology - Abstract
We study the influence of cellulose nanocrystals on the oil–water interfacial viscoelasticity and consequently on the emulsification and the three-phase (oil–water–solid) contact-line movement. Cel...
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- 2021
116. Dynamics of the Topological Network Formed by Movable Crosslinks: Effect of Sliding Motion on Dielectric and Viscoelastic Relaxation Behavior
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Tadashi Inoue, Yoshinori Takashima, Osamu Urakawa, Yu Kashiwagi, Akira Harada, and Sheng Zhao
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Materials science ,Polymers and Plastics ,Organic Chemistry ,Dynamics (mechanics) ,Motion (geometry) ,02 engineering and technology ,Dielectric ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Topology ,01 natural sciences ,Viscoelasticity ,0104 chemical sciences ,Relaxation behavior ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,Ethyl acrylate ,0210 nano-technology - Abstract
We investigated the dynamics of the topological network formed by rotaxane-type movable crosslinks consisting of a poly(ethyl acrylate) backbone threaded through peracetylated cyclodextrins, which ...
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- 2021
117. Dissecting Dynamics Near the Glass Transition Using Polyelectrolyte Complexes
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Joseph B. Schlenoff and Khalil Akkaoui
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chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Organic Chemistry ,Dynamics (mechanics) ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Polyelectrolyte ,0104 chemical sciences ,Amorphous solid ,Inorganic Chemistry ,chemistry ,Chemical physics ,Materials Chemistry ,0210 nano-technology ,Glass transition - Abstract
Though the strong transformation in mechanical properties of glass-forming materials such as amorphous polymers near the glass transition, Tg, has long been recognized and exploited, efforts to und...
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- 2021
118. Synthetic Control of Mitochondrial Dynamics: Developing Three-Coordinate Au(I) Probes for Perturbation of Mitochondria Structure and Function
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William C. Jennings, Jong-Hyun Kim, Gunnar F. Kwakye, Sean Parkin, Samuel G. Awuah, Samuel Ofori, and R. Tyler Mertens
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Chemistry ,Neurodegeneration ,Dynamics (mechanics) ,chemical probe ,Mitochondrion ,anticancer ,biogenesis ,medicine.disease ,Article ,Cell biology ,Structure and function ,mitochondria ,breast cancer ,Mitochondrial structure ,Biological target ,gold compounds ,medicine ,structure ,Mitochondrial homeostasis ,QD1-999 ,Biogenesis - Abstract
Mitochondrial structure and organization is integral to maintaining mitochondrial homeostasis and an emerging biological target in aging, inflammation, neurodegeneration, and cancer. The study of mitochondrial structure and its functional implications remains challenging in part because of the lack of available tools for direct engagement, particularly in a disease setting. Here, we report a gold-based approach to perturb mitochondrial structure in cancer cells. Specifically, the design and synthesis of a series of tricoordinate Au(I) complexes with systematic modifications to group 15 nonmetallic ligands establish structure–activity relationships (SAR) to identify physiologically relevant tools for mitochondrial perturbation. The optimized compound, AuTri-9 selectively disrupts breast cancer mitochondrial structure rapidly as observed by transmission electron microscopy with attendant effects on fusion and fission proteins. This phenomenon triggers severe depolarization of the mitochondrial membrane in cancer cells. The high in vivo tolerability of AuTri-9 in mice demonstrates its preclinical utility. This work provides a basis for rational design of gold-based agents to control mitochondrial structure and dynamics.
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- 2021
119. Unified Probability Distribution and Dynamics of Lead Contents in Human Erythrocytes Revealed by Single-Cell Analysis
- Author
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Chen Tao, Yongguang Yin, Huazhou Zhang, Yongshun Huang, Bin He, Ligang Hu, Maoyong Song, Baowei Chen, Guangbo Qu, Jianbo Shi, Nian Liu, Aiqian Zhang, Yong Liang, Guibin Jiang, and Ting Wang
- Subjects
Pollutant ,Erythrocytes ,Chemistry ,Dynamics (mechanics) ,Healthy subjects ,General Chemistry ,010501 environmental sciences ,01 natural sciences ,Single-cell analysis ,Gamma distribution ,Biophysics ,Humans ,Environmental Chemistry ,Probability distribution ,Human erythrocytes ,Distribution (pharmacology) ,Environmental Pollutants ,Single-Cell Analysis ,Probability ,0105 earth and related environmental sciences - Abstract
Understanding the presence and dynamics of chemical pollutants in individual cells is fundamentally important for their trafficking, fate, and toxicity in humans. The presence of molecular components (i.e., proteins and mRNA) in individual cells of higher organisms is considered a stochastic event. The characteristics of chemical pollutants, as extrinsic compounds, in subpopulation of human cells on single-cell basis have not been explored yet. Here, we demonstrated the lead (Pb) content in individual mature erythrocytes (m-erythrocytes) of Pb-intoxicated patients, and healthy subjects exhibited a unified pattern in probability distribution (gamma distribution) and dynamics, despite being highly heterogeneous. The Pb content in individual m-erythrocytes decreased with the lifetime of m-erythrocytes. Meanwhile, the distribution and dynamics were found to be highly related to the Pb content in m-erythrocytes and was independent of patients and their status. This is the first study to analyze the distribution pattern of chemical pollutants at a single-cell level in higher organisms. This study sheds light on the molecular mechanism of Pb trafficking and fate in humans and the search for an efficient strategy to improve Pb excretion during Pb treatment.
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- 2021
120. Probing the Intracellular Dynamics of Nitric Oxide and Hydrogen Sulfide Using an Activatable NIR II Fluorescence Reporter
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He Tian, Ning Ren, Tianli Zhu, Chunchang Zhao, Ying Zhu, Xia Liu, Jiang Li, Jie Sun, Lihua Wang, Chunhai Fan, Yan Dong, Rongchen Wang, and Jinzhu Gao
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010405 organic chemistry ,Hydrogen sulfide ,Dynamics (mechanics) ,General Chemistry ,General Medicine ,010402 general chemistry ,01 natural sciences ,Fluorescence ,Catalysis ,0104 chemical sciences ,Nitric oxide ,chemistry.chemical_compound ,chemistry ,Biophysics ,Signal transduction ,Molecular probe ,Intracellular ,Gasotransmitters - Abstract
Understanding the complex interplay among gasotransmitters is of great significance but remains technically challenging. In this study, we present the design and synthesis of a dually responsive BOD-NH-SC reporter for probing the dynamic and alternating existence of NO and H2 S in living cells. This designed reporter can repeatedly cycle S-nitrosation and transnitrosation reactions when successively treated with NO and H2 S, thus affording the interchange of NIR fluorescence at 645 nm (NO) and NIR II fluorescence at 936 nm (H2 S). In light of this unique fluorescence alternation between two colors, we synthesized water-soluble BOD-NH-SC dots to visualize the intracellular dynamics of NO and H2 S. These molecular probes thus provide a toolbox to elucidate the interplaying roles of NO and H2 S in the complex interaction networks of various signal transduction pathways.
- Published
- 2021
121. How wide is the window opened by high-resolution relaxometry on the internal dynamics of proteins in solution?
- Author
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Nicolas Bolik-Coulon, Matthias Ernst, Fabien Ferrage, Albert A. Smith, Beat H. Meier, Universität Leipzig [Leipzig], Laboratoire des biomolécules (LBM UMR 7203), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Chimie Moléculaire de Paris Centre (FR 2769), Institut de Chimie du CNRS (INC)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM), and Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)
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Relaxometry ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Article ,[CHIM]Chemical Sciences ,Isoleucine ,Nuclear Magnetic Resonance, Biomolecular ,Spectroscopy ,Detector analysis ,Ubiquitin ,010405 organic chemistry ,Chemistry ,Protein dynamics ,Resolution (electron density) ,Relaxation (NMR) ,Dynamics (mechanics) ,Detector ,Proteins ,Rotational diffusion ,Nanosecond ,Dynamics ,0104 chemical sciences ,Solutions ,Chemical physics ,Solution-state NMR - Abstract
The dynamics of molecules in solution is usually quantified by the determination of timescale-specific amplitudes of motions. High-resolution nuclear magnetic resonance (NMR) relaxometry experiments—where the sample is transferred to low fields for longitudinal (T1) relaxation, and back to high field for detection with residue-specific resolution—seeks to increase the ability to distinguish the contributions from motion on timescales slower than a few nanoseconds. However, tumbling of a molecule in solution masks some of these motions. Therefore, we investigate to what extent relaxometry improves timescale resolution, using the “detector” analysis of dynamics. Here, we demonstrate improvements in the characterization of internal dynamics of methyl-bearing side chains by carbon-13 relaxometry in the small protein ubiquitin. We show that relaxometry data leads to better information about nanosecond motions as compared to high-field relaxation data only. Our calculations show that gains from relaxometry are greater with increasing correlation time of rotational diffusion., Journal of Biomolecular NMR, 75 (2-3), ISSN:0925-2738, ISSN:1573-5001
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- 2021
122. Mathematical model of transmembrane potential dynamics of loach early embryogenesis
- Author
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Z. Y. Fedorovych, Z. D. Vorobets, E. I. Lychkovsky, and G. V. Galyk
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Membrane potential ,0303 health sciences ,Mathematical model ,Correlation coefficient ,Chemistry ,Dynamics (mechanics) ,Embryogenesis ,Embryo ,General Medicine ,010501 environmental sciences ,01 natural sciences ,03 medical and health sciences ,Water environment ,Biophysics ,Incubation ,030304 developmental biology ,0105 earth and related environmental sciences - Abstract
Heavy metals in the water environment are known to have a negative effect on the viability of fish in early development. We have discussed the influence of environmental factors on early embryo development from the viewpoint of the correlation adaptometry method. The analysis of time series with the subsequent construction of a mathematical model was used to determine the change in the greatest effect of certain types of ions on the values of the transmembrane potential for prognostic purposes. The membrane potential is accepted as an integral indicator of the state of the embryos. Structures of five elements of the same type were constructed for the time shifts from 0 to 180 minutes. Each element in the system characterizes the value of the transmembrane potential that was measured in a cell incubated in one of the five solutions during early embryo development. Mathematical models describing the cell membrane potential dynamics have been created and studied. It was noted that the transmembrane potential dynamics of embryo cells is dependent on a change in the value of the correlation coefficient between elements of the system. A decrease in the sum of the correlations between individual elements of the system with an increase in the magnitude of the time shift is established. The results of the numerical solutions of the system equations indicated the sequence of changes in the greatest effect of the incubation medium on the value of the membrane potential in cells. The study of the membrane potentials’ dynamics, using the total values of the strength of correlation, confirmed the influence of heavy metals in the incubation medium on the membrane potential of embryo cell in early development.
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- 2021
123. Polymer Electrolytes in Strong External Electric Fields: Modification of Structure and Dynamics
- Author
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Diddo Diddens, Alina Wettstein, and Andreas Heuer
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Materials science ,Polymers and Plastics ,Polymer electrolytes ,FOS: Physical sciences ,02 engineering and technology ,Condensed Matter - Soft Condensed Matter ,010402 general chemistry ,01 natural sciences ,Inorganic Chemistry ,Molecular dynamics ,chemistry.chemical_compound ,Physics - Chemical Physics ,Electric field ,Materials Chemistry ,Chemical Physics (physics.chem-ph) ,Ethylene oxide ,Organic Chemistry ,Doping ,Dynamics (mechanics) ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Chemical physics ,ddc:540 ,Soft Condensed Matter (cond-mat.soft) ,0210 nano-technology - Abstract
We present the results from an extensive atomistic molecular dynamics simulation study of poly(ethylene oxide) (PEO) doped with various amounts of lithium-bis(trifluoromethane)sulfonimide (LiTFSI) salt under the influence of external electric field strengths up to $1\,$V/nm. The motivation stems from recent experimental reports on the nonlinear response of mobilities to the application of an electric field in such electrolyte systems and arising speculations on field-induced alignment of the polymer chains, creating channel-like structures that facilitate ion passage. Hence, we systematically examine the electric field impact on the lithium coordination environment, polymer structure as well as ionic transport properties and further present a procedure to quantify the susceptibility of both structural and dynamical observables to the external field. Our investigation reveals indeed a coiled-to-stretched transformation of the PEO strands along with a concurrent nonlinear behavior of the dynamic properties. However, from studying the temporal response of the unperturbed electrolyte system to field application we are able to exclude a structurally conditioned enhancement of ion transport and surprisingly observe a slowing down. A microscopic understanding is supplied., Main manuscript comprises 30 pages and 13 figures, supplementary information section comprises 30 pages and 28 figures
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- 2021
124. On the stability of protein–DNA complexes in molecular dynamics simulations using the CUFIX corrections
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Jejoong Yoo
- Subjects
010302 applied physics ,chemistry.chemical_classification ,Physics ,Biomolecule ,Dynamics (mechanics) ,Protein dna ,General Physics and Astronomy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Electrostatics ,01 natural sciences ,Stability (probability) ,Force field (chemistry) ,Molecular dynamics ,chemistry ,Chemical physics ,0103 physical sciences ,Diffusion (business) ,0210 nano-technology - Abstract
The molecular dynamics simulation using the so-called force field is a computational method to investigate the conformational stability and dynamics of various biomolecules, including proteins and nucleic acids. While a force-balanced force field is necessary for realistic simulations, recent studies revealed that all standard CHARMM and AMBER force fields over-stabilize the protein–DNA interfaces, resulting in abnormally slow diffusion of DNA-binding proteins. To address this issue, we recently developed the CUFIX corrections by calibrating the electrostatic interactions at the protein–DNA interfaces and demonstrated that the CUFIX corrections dramatically improved the diffusion dynamics of DNA-binding proteins. However, whether the improvement was achieved correctly or at the cost of abnormal destabilization of protein–DNA interactions should be validated. Here, we prove that the CUFIX corrections achieved the balance by demonstrating that the CUFIX corrections maintain the complex structure of DNA and a histone-like protein, Hbb.
- Published
- 2021
125. Evolution dynamics of voids in single crystal copper under triaxial loading condition
- Author
-
Sunil Rawat and Shashank Chaturvedi
- Subjects
010302 applied physics ,Coalescence (physics) ,Materials science ,Dynamics (mechanics) ,Nucleation ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Spall ,01 natural sciences ,Copper ,Molecular dynamics ,chemistry ,0103 physical sciences ,Fracture (geology) ,Composite material ,0210 nano-technology ,Single crystal - Abstract
An understanding of nucleation, growth and coalescence of voids is required to predict the spall fracture. We employ molecular dynamics simulations to investigate the effect of temperature on the n...
- Published
- 2021
126. Hydrogen Bonding and Its Effect on the Orientational Dynamics of Water Molecules inside Polyelectrolyte Brush-Induced Soft and Active Nanoconfinement
- Author
-
Siddhartha Das, Harnoor Singh Sachar, Bhargav Sai Chava, and Turash Haque Pial
- Subjects
Properties of water ,Materials science ,Polymers and Plastics ,Hydrogen bond ,Organic Chemistry ,Dynamics (mechanics) ,Brush ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Polyelectrolyte ,0104 chemical sciences ,law.invention ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Chemical physics ,law ,Materials Chemistry ,Molecule ,0210 nano-technology ,Earth (classical element) - Abstract
Despite being the most ubiquitous compound on Earth, the fundamental properties of water are not fully understood, especially in nanoconfinement. Densely grafted polyelectrolyte (PE) molecules atta...
- Published
- 2021
127. Lyapunov stability of competitive cells dynamics in tumor mechanobiology
- Author
-
Angelo Rosario Carotenuto, Stefania Palumbo, Massimiliano Fraldi, A. Cutolo, Carotenuto, A. R., Cutolo, A., Palumbo, S., and Fraldi, M.
- Subjects
Lyapunov stability ,0303 health sciences ,Work (thermodynamics) ,Volterra-Lotka dynamics ,Chemistry ,Mechanical Engineering ,Poromechanics ,Dynamics (mechanics) ,Computational Mechanics ,Context (language use) ,02 engineering and technology ,Poroelasticity ,021001 nanoscience & nanotechnology ,03 medical and health sciences ,Nonlinear system ,Mechanobiology ,Order (biology) ,0210 nano-technology ,Biological system ,Stability ,Cells competition ,Tumor growth ,030304 developmental biology - Abstract
Abstract Poromechanics plays a key role in modelling hard and soft tissue behaviours, by providing a thermodynamic framework in which chemo-mechanical mutual interactions among fluid and solid constituents can be consistently rooted, at different scale levels. In this context, how different biological species (including cells, extra-cellular components and chemical metabolites) interplay within complex environments is studied for characterizing the mechanobiology of tumor growth, governed by intratumoral residual stresses that initiate mechanotransductive processes deregulating normal tissue homeostasis and leading to tissue remodelling. Despite the coupling between tumor poroelasticity and interspecific competitive dynamics has recently highlighted how microscopic cells and environment interactions influence growth-associated stresses and tumor pathophysiology, the nonlinear interlacing among biochemical factors and mechanics somehow hindered the possibility of gaining qualitative insights into cells dynamics. Motivated by this, in the present work we recover the linear poroelasticity in order to benefit of a reduced complexity, so first deriving the well-known Lyapunov stability criterion from the thermodynamic dissipation principle and then analysing the stability of the mechanical competition among cells fighting for common space and resources during cancer growth and invasion. At the end, the linear poroelastic model enriched by interspecific dynamics is also exploited to show how growth anisotropy can alter the stress field in spherical tumor masses, by thus indirectly affecting cell mechano-sensing. GraphicAbstract
- Published
- 2021
128. NMR spectroscopy captures the essential role of dynamics in regulating biomolecular function
- Author
-
T. Reid Alderson and Lewis E. Kay
- Subjects
chemistry.chemical_classification ,0303 health sciences ,DNA Copy Number Variations ,Biomolecule ,Dynamics (mechanics) ,Nuclear magnetic resonance spectroscopy ,Biology ,General Biochemistry, Genetics and Molecular Biology ,Molecular machine ,03 medical and health sciences ,0302 clinical medicine ,chemistry ,Structural biology ,Mutation ,Humans ,Transcriptome ,Spectroscopy ,Biological system ,Nuclear Magnetic Resonance, Biomolecular ,Conformational ensembles ,Biomarkers ,030217 neurology & neurosurgery ,Function (biology) ,030304 developmental biology - Abstract
Biomolecules are in constant motion. To understand how they function, and why malfunctions can cause disease, it is necessary to describe their three-dimensional structures in terms of dynamic conformational ensembles. Here, we demonstrate how nuclear magnetic resonance (NMR) spectroscopy provides an essential, dynamic view of structural biology that captures biomolecular motions at atomic resolution. We focus on examples that emphasize the diversity of biomolecules and biochemical applications that are amenable to NMR, such as elucidating functional dynamics in large molecular machines, characterizing transient conformations implicated in the onset of disease, and obtaining atomic-level descriptions of intrinsically disordered regions that make weak interactions involved in liquid-liquid phase separation. Finally, we discuss the pivotal role that NMR has played in driving forward our understanding of the biomolecular dynamics-function paradigm.
- Published
- 2021
129. Comparative study of the dynamics of laser breakdown in water and hexane using interference microscopy
- Author
-
V. M. Gololobov, V. V. Kononenko, Vitaly I. Konov, E. A. Goncharov, and Taras V. Kononenko
- Subjects
Materials science ,business.industry ,Dynamics (mechanics) ,Statistical and Nonlinear Physics ,Atomic and Molecular Physics, and Optics ,Interference microscopy ,Electronic, Optical and Magnetic Materials ,Hexane ,chemistry.chemical_compound ,chemistry ,Optoelectronics ,Femtosecond laser radiation ,Electrical and Electronic Engineering ,Laser breakdown ,business - Abstract
The changes in the optical properties of water and hexane under femtosecond irradiation (Ti : Al2O3 laser, wavelength 800 nm, intensity ∼1013 W cm−2) are investigated in the cavitation (bubble-formation) regime using interference microscopy in a time interval of ∼1.5 ns since the impact onset. A comparison of the dynamics of radiation-induced processes (solvation of excess electrons, pair recombination, and development of precavitation processes) is performed. The excited-carrier concentration is estimated, and these estimates are found to be inconsistent with the amount of energy that must be transferred to the liquid during a pulse to implement its heating and subsequent cavitation. This inconsistency is especially pronounced for hexane, where ionisation processes can barely be detected by interferometry. The experimental results put new questions about the mechanisms of energy transfer in both polar and nonpolar liquids subjected to intense laser irradiation.
- Published
- 2021
130. Dynamics of morphology of myocardium in neonatal lambs
- Author
-
V.V. Lemeshchenko, Environmental Sciencesl Fsaei He, and I.A. Filonova
- Subjects
Morphology (linguistics) ,Chemistry ,Dynamics (mechanics) ,Biophysics ,General Medicine - Published
- 2021
131. In vivo Ca2+ dynamics during cooling after eccentric contractions in rat skeletal muscle
- Author
-
Yutaka Kano, Ayaka Tabuchi, Ryo Ikegami, David C. Poole, Tomoyo Asamura, Yoshinori Tanaka, Daisuke Hoshino, Ryo Takagi, and Seiya Hirayama
- Subjects
Physiology ,Ryanodine receptor ,Chemistry ,medicine.medical_treatment ,Dynamics (mechanics) ,Skeletal muscle ,Eccentric contractions ,Cryotherapy ,030229 sport sciences ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Intracellular calcium ion ,In vivo ,Eccentric exercise ,Physiology (medical) ,Biophysics ,medicine ,030217 neurology & neurosurgery - Abstract
The effect of cooling on in vivo intracellular calcium ion concentration [Ca2+]i after eccentric contractions (ECs) remains to be determined. We tested the hypothesis that cryotherapy following ECs promotes an increased [Ca2+]i and induces greater muscle damage in two muscles with substantial IIb and IIx fiber populations. The thin spinotrapezius (SPINO) muscles of Wistar rats were used for in vivo [Ca2+]i imaging, and tibialis anterior (TA) muscles provided greater fidelity and repeatability of contractile function measurements. SPINO [Ca2+]i was estimated using fura 2-AM and the magnitude, location, and temporal profile of [Ca2+]i determined as the temperature near the muscle surface post-ECs was decreased from 30°C (control) to 20°C or 10°C. Subsequently, in the TA, the effect of post-ECs cooling to 10°C on muscle contractile performance was determined at 1 and 2 days after ECs. TA muscle samples were examined by hematoxylin and eosin staining to assess damage. In SPINO, reducing the muscle temperature from 30°C to 10°C post-ECs resulted in a 3.7-fold increase in the spread of high [Ca2+]i sites generated by ECs ( P < 0.05). These high [Ca2+]i sites demonstrated partial reversibility when rewarmed to 30°C. Dantrolene, a ryanodine receptor Ca2+ release inhibitor, reduced the presence of high [Ca2+] sites at 10°C. In the TA, cooling exacerbated ECs-induced muscle strength deficits via enhanced muscle fiber damage ( P < 0.05). By demonstrating that cooling post-ECs potentiates [Ca2+]i derangements, this in vivo approach supports a putative mechanistic basis for how postexercise cryotherapy might augment muscle fiber damage and decrease subsequent exercise performance.
- Published
- 2021
132. Structural Transition Dynamics in Carbon <scp>Electrode‐Based Single‐Molecule</scp> Junctions
- Author
-
Xuefeng Guo, Li Peihui, and Chuancheng Jia
- Subjects
chemistry.chemical_classification ,Chemical physics ,Chemistry ,Dynamics (mechanics) ,Electrode ,Stereoelectronic effect ,Molecular electronics ,Molecule ,Non-covalent interactions ,chemistry.chemical_element ,Structural transition ,General Chemistry ,Carbon - Published
- 2021
133. Structure, Molecular Interactions, and Dynamics of Aqueous [BMIM][BF4] Mixtures: A Molecular Dynamics Study
- Author
-
Stephanie E. Billeck and Tsun-Mei Chang
- Subjects
Molecular interactions ,Aqueous solution ,010304 chemical physics ,Chemistry ,Dynamics (mechanics) ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Molecular dynamics ,Polarizability ,Chemical physics ,0103 physical sciences ,Materials Chemistry ,Physics::Chemical Physics ,Physical and Theoretical Chemistry - Abstract
Molecular dynamics simulations with many-body polarizable force fields were carried out to investigate the thermodynamic, structural, and dynamic properties of aqueous solutions of 1-butyl-3-methyl...
- Published
- 2021
134. Dynamics of copper–water nanofluid with the significance of prescribed thermal conditions
- Author
-
Iftikhar Ahmad, Muhammad Faisal, and Tariq Javed
- Subjects
Fluid Flow and Transfer Processes ,Unsteady flow ,Nanofluid ,Materials science ,chemistry ,Dynamics (mechanics) ,Thermal ,chemistry.chemical_element ,Mechanics ,Magnetohydrodynamics ,Condensed Matter Physics ,Porous medium ,Copper - Published
- 2021
135. Effect of pH on the Dynamics and Structure of Thermoresponsive Telechelic Polyelectrolyte Networks: Impact on Hydrogel Injectability
- Author
-
Christine M. Papadakis, Maria Rikkou-Kalourkoti, Maria Malvina Soledad Lencina, Costas S. Patrickios, Constantinos Tsitsilianis, Chia-Hsin Ko, Ralf Schweins, and Florian Jung
- Subjects
Polymers and Plastics ,Chemical engineering ,Chemistry ,Process Chemistry and Technology ,Organic Chemistry ,Dynamics (mechanics) ,Polyelectrolyte - Abstract
We report the effect of pH on the dynamics and structure of 3D networks formed by the temperature-dependent hydrophobic association of the end blocks of P(nBuMA18-co-TEGMA15)-b-PDMAEMA159-b-P(nBuMA...
- Published
- 2021
136. {101̄2} twinning in single-crystal titanium under shock loading
- Author
-
Nilanjan Mitra and Sunil Rawat
- Subjects
010302 applied physics ,Materials science ,Astrophysics::High Energy Astrophysical Phenomena ,Dynamics (mechanics) ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Compression (physics) ,01 natural sciences ,Shock (mechanics) ,Molecular dynamics ,chemistry ,Condensed Matter::Superconductivity ,0103 physical sciences ,Perpendicular ,Composite material ,0210 nano-technology ,Crystal twinning ,Single crystal ,Astrophysics::Galaxy Astrophysics ,Titanium - Abstract
We employ molecular dynamics simulations to investigate the evolution dynamics of {101¯2} twinning in single-crystal Ti under shock loading. The shock compression applied perpendicular to the c-axi...
- Published
- 2021
137. Hybrid Forces Molecular Dynamics on the Lability, Dynamics and 'Structure Breaking Effect' of Cs+ in Liquid Ammonia
- Author
-
Fitria Rahmawati, Niko Prasetyo, Yuniawan Hidayat, I.F. Nurcahyo, and Harno Dwi Pranowo
- Subjects
Molecular dynamics ,Solvation shell ,Field (physics) ,Lability ,Chemistry ,Chemical physics ,Dynamics (mechanics) ,Physics::Atomic and Molecular Clusters ,Solvation ,Charge (physics) ,General Chemistry ,Physics::Chemical Physics ,Quantum - Abstract
The lability, dynamics of the first solvation shell, and structure breaking effect properties of Cs+ in liquid ammonia have been evaluated using Quantum Mechanical Charge Field Molecular Dynamics (...
- Published
- 2021
138. Impact of Cyclic Strain on the Structural Relaxation Dynamics of Macrocyclic Thiophenes
- Author
-
Dongho Kim, Juwon Oh, Hyeyoung Joung, Jaesung Yang, and Woojae Kim
- Subjects
chemistry.chemical_classification ,Cyclic strain ,Quantitative Biology::Biomolecules ,Materials science ,Condensed Matter::Other ,Exciton ,Dynamics (mechanics) ,Polymer ,Conjugated system ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter::Disordered Systems and Neural Networks ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Charge generation ,Condensed Matter::Materials Science ,Delocalized electron ,General Energy ,chemistry ,Chemical physics ,Relaxation (physics) ,Physical and Theoretical Chemistry - Abstract
The delocalized exciton on conjugated polymers plays a momentous role in efficient charge generation and transport processes. Because the exciton is delocalized over the conjugated backbone, the ex...
- Published
- 2021
139. Insights in the structural understanding of amyloidogenicity and mutation-led conformational dynamics of amyloid beta (Aβ) through molecular dynamics simulations and principal component analysis
- Author
-
Saleem Iqbal, Krishnasamy Gunasekaran, Sriram Srinivasa Raghavan, and Niraikulam Ayyadurai
- Subjects
Amyloid beta ,030303 biophysics ,Peptide ,Molecular Dynamics Simulation ,Abnormal protein ,03 medical and health sciences ,Molecular dynamics ,Alzheimer Disease ,Structural Biology ,medicine ,Humans ,Molecular Biology ,chemistry.chemical_classification ,Principal Component Analysis ,0303 health sciences ,Amyloid beta-Peptides ,biology ,Chemistry ,Nervous tissue ,Dynamics (mechanics) ,General Medicine ,Peptide Fragments ,Cell biology ,medicine.anatomical_structure ,Mutation ,Mutation (genetic algorithm) ,Principal component analysis ,biology.protein - Abstract
Abnormal protein aggregation in the nervous tissue leads to several neurodegenerative disorders like Alzheimer's disease (AD). In AD, accumulation of the amyloid beta (Aβ) peptide is proposed to be an early important event in pathogenesis. Significant research efforts are devoted so as to understand the Aβ misfolding and aggregation. Molecular dynamics (MD) simulations complement experiments and provide structural information at the atomic level with dynamics without facing the same experimental limitations. Artificial missense mutations are employed experimentally and computationally for providing insights into the structure-function relationships of amyloid-β in relation to the pathologies of AD. Present work describes the MD simulations for 100 ns so as to probe the structural and conformational dynamics of Aβ1-42 assemblies and its mutants. Essential dynamics analysis with respect to conformational deviation of
- Published
- 2021
140. Wetting Dynamics on Solvophilic, Soft, Porous, and Responsive Surfaces
- Author
-
Siddhartha Das, Sai Ankit Etha, Parth Rakesh Desai, and Harnoor Singh Sachar
- Subjects
chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Organic Chemistry ,Dynamics (mechanics) ,Liquid drop ,Polymer ,Inorganic Chemistry ,Molecular dynamics ,Chemical engineering ,chemistry ,Materials Chemistry ,Imbibition ,Wetting ,Porosity ,Layer (electronics) - Abstract
We employ molecular dynamics (MD) simulations to study the spreading and imbibition of a liquid drop on a porous, soft, solvophilic, and responsive surface represented by a layer of polymer molecul...
- Published
- 2021
141. Novel insights in linking solvent relaxation dynamics and protein conformations utilizing red edge excitation shift approach
- Author
-
Rupasree Brahma and H. Raghuraman
- Subjects
0301 basic medicine ,Fluorophore ,Protein Conformation ,Dynamics (mechanics) ,Relaxation (NMR) ,Solvation ,Proteins ,Context (language use) ,Protein aggregation ,010402 general chemistry ,01 natural sciences ,Article ,General Biochemistry, Genetics and Molecular Biology ,0104 chemical sciences ,Solvent ,03 medical and health sciences ,chemistry.chemical_compound ,Spectrometry, Fluorescence ,030104 developmental biology ,chemistry ,Chemical physics ,Solvents ,General Agricultural and Biological Sciences ,Excitation ,Fluorescent Dyes - Abstract
Protein hydration dynamics plays an important role in many physiological processes since protein fluctuations, slow solvation, and the dynamics of hydrating water are all intrinsically related. Red edge excitation shift (REES) is a unique and powerful wavelength-selective (i.e. excitation-energy dependent) fluorescence approach that can be used to directly monitor the environment-induced restriction and dynamics around a polar fluorophore in a complex biological system. This review is mainly focused on recent applications of REES and a novel analysis of REES data to monitor the structural dynamics, functionally relevant conformational transitions and to unmask the structural ensembles in proteins. In addition, the novel utility of REES in imaging protein aggregates in a cellular context is discussed. We believe that the enormous potential of REES approach showcased in this review will engage more researchers, particularly from life sciences.
- Published
- 2021
142. Conformational Dynamics of Deubiquitinase A and Functional Implications
- Author
-
Ashish Kabra and Ying Li
- Subjects
Future studies ,biology ,Protein Conformation ,Chemistry ,Dynamics (mechanics) ,Molecular Dynamics Simulation ,Biochemistry ,Article ,Negative regulator ,Deubiquitinating enzyme ,Serine ,Functional importance ,Endopeptidases ,Helix ,biology.protein ,Biophysics ,Humans ,Phosphorylation ,Nuclear Magnetic Resonance, Biomolecular - Abstract
Deubiquitinase A (DUBA) belongs to the ovarian tumor family of deubiquitinating enzymes and was initially identified as a negative regulator of type I interferons, whose overproduction has been linked to autoimmune diseases. The deubiquitinating activity of DUBA is positively regulated by phosphorylation at a single serine residue, S177, which results in minimal structural changes. We have previously shown that phosphorylation induces a two-state conformational equilibrium observed only in the active form of DUBA, highlighting the functional importance of DUBA dynamics. Here, we report the conformational dynamics of DUBA on the microsecond-to-millisecond time scales characterized by nuclear magnetic resonance relaxation dispersion experiments. We found that motions on these time scales are highly synchronized in the phosphorylated and nonphosphorylated DUBA. Despite the overall similarity of these two forms, different dynamic properties were observed in helix α1 and the neighboring regions, including residue S177, which likely contribute to the activation of DUBA by phosphorylation. Moreover, our data suggest that transient unfolding of helix α6 drives the global conformational process and that mutations can be introduced to modulate this process, which provides a basis for future studies to define the exact functional roles of motions in DUBA activation and substrate specificity.
- Published
- 2021
143. Enhanced Dynamics of PMMA Brushes Induced by the Chain Ends of a Flexible Polymer Chain
- Author
-
Dandan Sun, Biao Zuo, Yun Li, Jian-Hua Huang, Xinping Wang, Xin Wang, Yuhui Yang, and Ziyu Wang
- Subjects
Inorganic Chemistry ,chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Chain (algebraic topology) ,Chemical engineering ,chemistry ,Organic Chemistry ,Dynamics (mechanics) ,Materials Chemistry ,Copolymer ,Polymer - Abstract
The dynamics of different blocks in block copolymers are expected to affect the other blocks due to compositional heterogeneity, thus influencing their bulk structure and performance. It is signifi...
- Published
- 2021
144. Direct Dynamics Simulations of the 3CH2 + 3O2 Reaction at High Temperature
- Author
-
Sandhiya Lakshmanan, Subha Pratihar, and William L. Hase
- Subjects
Exothermic reaction ,Reaction rate constant ,Chemistry ,Product (mathematics) ,Dynamics (mechanics) ,Analytical chemistry ,Singlet state ,Physical and Theoretical Chemistry ,Negative temperature ,Ground state - Abstract
Direct dynamics simulations with the M06/6-311++G(d,p) level of theory were performed to study the 3CH2 + 3O2 reaction at 1000 K temperature on the ground state singlet surface. The reaction is complex with formation of many different product channels in highly exothermic reactions. CO, CO2, H2O, OH, H2, O, H, and HCO are the products formed from the reaction. The total simulation rate constant for the reaction at 1000 K is (1.2 ± 0.3) × 10-12 cm3 molecule-1 s-1, while the simulation rate constant at 300 K is (0.96 ± 0.28) × 10-12 cm3 molecule-1 s-1. The simulated product yields show that CO is the dominant product and the CO:CO2 ratio is 5.3:1, in good comparison with the experimental ratio of 4.3:1 at 1000 K. On comparing the product yields for the 300 and 1000 K simulations, we observed that, except for CO and H2O, the yields of the other products at 1000 K are lower at 300 K, showing a negative temperature dependence.
- Published
- 2021
145. DYNAMICS OF MARKERS OF METABOLIC PROCESSES IN BONE TISSUE WITH STIMULATION OF OSTEOREGENERATION IN TUBULAR BONE FRACTURES IN RATS
- Author
-
Vladimir Vyacheslavovich Reshetnyak, Vasiliy Vladimirovich Burdeynyi, and Yevgenyi Aidarkhanovich Iskaliev
- Subjects
Tubular bone ,Pathology ,medicine.medical_specialty ,medicine.anatomical_structure ,Chemistry ,Dynamics (mechanics) ,medicine ,Stimulation ,Bone tissue - Published
- 2021
146. 3D magnetically controlled spatiotemporal probing and actuation of collagen networks from a single cell perspective
- Author
-
Vahid Hosseini, Simone Schuerle, Thomas M. Valentin, Daphne O. Asgeirsson, Amin Hosseini Nami, Luca Somm, Nima Mirkhani, and Michael G. Christiansen
- Subjects
0303 health sciences ,Materials science ,Dynamics (mechanics) ,Biomedical Engineering ,Bioengineering ,Context (language use) ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Models, Biological ,Biochemistry ,Extracellular Matrix ,Magnetic field ,Extracellular matrix ,Shear (sheet metal) ,Chemistry ,03 medical and health sciences ,Matrix (mathematics) ,Collagen ,Fiber ,Deformation (engineering) ,0210 nano-technology ,Biological system ,030304 developmental biology - Abstract
Cells continuously sense and react to mechanical cues from their surrounding matrix, which consists of a fibrous network of biopolymers that influences their fate and behavior. Several powerful methods employing magnetic control have been developed to assess the micromechanical properties within extracellular matrix (ECM) models hosting cells. However, many of these are limited to in-plane sensing and actuation, which does not allow the matrix to be probed within its full 3D context. Moreover, little attention has been given to factors specific to the model ECM systems that can profoundly influence the cells contained there. Here we present methods to spatiotemporally probe and manipulate extracellular matrix networks at the scale relevant to cells using magnetic microprobes (mu Rods). Our techniques leverage 3D magnetic field generation, physical modeling, and image analysis to examine and apply mechanical stimuli to fibrous collagen matrices. We determined shear moduli ranging between hundreds of Pa to tens of kPa and modeled the effects of proximity to rigid surfaces and local fiber densification. We analyzed the spatial extent and dynamics of matrix deformation produced in response to magnetic torques on the order of 10 pNm, deflecting fibers over an area spanning tens of micrometers. Finally, we demonstrate 3D actuation and pose extraction of fluorescently labelled mu Rods., Lab on a Chip, 21 (20), ISSN:1473-0197, ISSN:1473-0189
- Published
- 2021
147. Anomalous structural dynamics of minimally frustrated residues in cardiac troponin C triggers hypertrophic cardiomyopathy
- Author
-
Maicon Landim-Vieira, Jose R. Pinto, Bin Sun, Elio A. Cino, Isela C. Valera, Peter M. Kekenes-Huskey, Karissa M. Dieseldorff Jones, Jamie R. Johnston, Adolfo H. Moraes, Michelle S. Parvatiyar, Jerson L. Silva, Guilherme A. P. de Oliveira, Vitold E. Galkin, P. Bryant Chase, and Mayra A. Marques
- Subjects
Genetically modified mouse ,0303 health sciences ,Myofilament ,Mutation ,Chemistry ,030302 biochemistry & molecular biology ,Dynamics (mechanics) ,Hypertrophic cardiomyopathy ,General Chemistry ,musculoskeletal system ,medicine.disease ,medicine.disease_cause ,Sarcomere ,Cell biology ,03 medical and health sciences ,medicine ,Structural rigidity ,Function (biology) ,030304 developmental biology - Abstract
Cardiac TnC (cTnC) is highly conserved among mammals, and genetic variants can result in disease by perturbing Ca2+-regulation of myocardial contraction. Here, we report the molecular basis of a human mutation in cTnC's αD-helix (TNNC1-p.C84Y) that impacts conformational dynamics of the D/E central-linker and sampling of discrete states in the N-domain, favoring the “primed” state associated with Ca2+ binding. We demonstrate cTnC's αD-helix normally functions as a central hub that controls minimally frustrated interactions, maintaining evolutionarily conserved rigidity of the N-domain. αD-helix perturbation remotely alters conformational dynamics of the N-domain, compromising its structural rigidity. Transgenic mice carrying this cTnC mutation exhibit altered dynamics of sarcomere function and hypertrophic cardiomyopathy. Together, our data suggest that disruption of evolutionary conserved molecular frustration networks by a myofilament protein mutation may ultimately compromise contractile performance and trigger hypertrophic cardiomyopathy., Cardiac TnC (cTnC) is highly conserved among mammals, and genetic variants can result in disease by perturbing Ca2+-regulation of myocardial contraction.
- Published
- 2021
148. THE DYNAMICS OF PROTEIN METABOLISM INDICATORS IN HYPOTROPHIC CALVES WHEN USING RECOMBINANT INTERFERON-LAMBDA
- Author
-
G. G. Chusova, Therapy», Voronezh, Russia, Nina A. Khokhlova, G. A. Vostroilova, Yu. A. Chaplygina, L. Yu. Sashnina, and E. V. Kosyakova
- Subjects
chemistry.chemical_compound ,Recombinant interferon ,chemistry ,Biochemistry ,Dynamics (mechanics) ,Protein metabolism ,General Medicine ,Lambda - Published
- 2021
149. Features of Albendazole Determination and Dynamics of Its Decomposition in Biological Material
- Author
-
D.P. Shcherbakov, S.Yu. Garmonov, and V.K. Shormanov
- Subjects
Chemistry ,Dynamics (mechanics) ,medicine ,General Earth and Planetary Sciences ,General Chemistry ,General Agricultural and Biological Sciences ,Biological system ,Decomposition ,General Biochemistry, Genetics and Molecular Biology ,Biological materials ,Albendazole ,medicine.drug - Published
- 2021
150. Mode-specific dynamics in multichannel reaction NH+ + H2
- Author
-
Le Yu, Weiliang Shi, Kun Wang, Ping Zhang, and Anyang Li
- Subjects
Coupling ,Hydrogen ,chemistry ,Saddle point ,Potential energy surface ,Dynamics (mechanics) ,Ab initio ,General Physics and Astronomy ,chemistry.chemical_element ,Physical chemistry ,Reactivity (chemistry) ,Physical and Theoretical Chemistry ,Excitation - Abstract
The vibrational- and rotational-mode specificity of the multichannel NH+ + H2 reaction is studied on a recently constructed ab initio-based global potential energy surface using an initial state selected quasi-classical trajectory method, and the trajectories are analyzed using an isometric feature mapping and k-means approach. All excitation modes promote two reactions (R1: NH′+ + H2 → NH+ + HH′ and R4: NH′+ + H2 → NH2+ + H′) where both NH and HH bonds are broken, but reduce the reactivity of the proton-transfer reaction R2 (NH′+ + H2 → N + H′H2+) at low collision energies. For the hydrogen-transfer reaction R3 (NH′+ + H2 → HNH′+ + H), the rotational excitation of NH+ enhances the reactivity remarkably, while its vibrational excitation has an inhibiting effect on the reaction. The trajectory analyses show that the vibrational and rotational excitations of NH+ make R3 tend to go over a submerged saddle point instead of extracting hydrogen atoms directly. On the other hand, the motions of the H2 reactant facilitate the enhancement of the reactivity but they do not affect the mechanism of R3. In addition, the results suggest that the coupling of the isometric feature mapping and the k-means approach in the trajectory analysis is an appropriate tool for reaction-dynamics studies.
- Published
- 2021
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