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Kinetic chain

Lun Peng, Zhiyun Li, Xiaohui Li, Hui Xue, Weidong Zhang, Gaojian Chen
Glycopolymers attached to a surface possess the ability to bind to certain carbohydrate binding proteins in a highly specific manner, and because of this, the fabrication of glycopolymer-modified surfaces has evolved as an effective route toward bioresponsive systems. Poly(N-3,4-dihydroxybenzenethyl methacrylamide-co-2-(methacrylamido) glucopyranose) copolymers, containing sugar and catechol functionalities, are for the first time successfully prepared in a well-controlled manner via room temperature single-electron transfer initiation and propagation through radical addition fragmentation chain transfer technique...
December 1, 2016: Macromolecular Rapid Communications
Richard W Willy, Erik P Meira
: Patellofemoral pain (PFP) has historically been a complex and enigmatic issue. Many of the factors thought to relate to PFP remain after patients' symptoms have resolved making their clinical importance difficult to determine. The tissue homeostasis model proposed by Dye in 2005 can assist with understanding and implementing biomechanical interventions for PFP. Under this model, the goal of interventions for PFP should be to re-establish patellofemoral joint (PFJ) homeostasis through a temporary alteration of load to the offended tissue, followed by incrementally restoring the envelope of function to the baseline level or higher...
December 2016: International Journal of Sports Physical Therapy
Xizi Cao, Mengyi Chen, Jun Ma, Baoqi Yin, Xiaopeng Xing
Atomic oxygen on silver is the crucial active species in many catalytic oxidation processes, while it is a big challenge to explore the relationship between its activity and molecular-level structures in condensed phases. We carried out kinetic measurements of the gas phase reactions between AgnO(-) (n = 1-8) and CO, in which the oxygen atoms were predicted to be terminal ones in AgO(-) and Ag2O(-), in quasi-Ag-O-Ag chains for Ag3O(-) and Ag4O(-), and on the two-fold or three-fold bridging positions in AgnO(-) (n = 5-8)...
November 30, 2016: Physical Chemistry Chemical Physics: PCCP
Peter C Burgers, John L Holmes, Johan K Terlouwc
The relative affinity of the monovalent metal ions Li(+), Na(+), Cu(+) and Ag(+) towards a series of aliphatic alkyl acetates and some selected 1-alkenes (P) was examined using the kinetic method. A detailed analysis of the dissociation characteristics of a series of mixed metal-bound dimer ions of the type P1-M(+)-P2 and the evaluated proton affinities (PAs) of the monomers shows that the affinity of the cation towards long-chain alkyl acetates and alkenes (having a chain length ≤ C4) is markedly enhanced...
2016: European Journal of Mass Spectrometry
Tatsuro Nakamura, Naho Yamaguchi, Yuu Miyauchi, Tomoki Takeda, Yasushi Yamazoe, Kiyoshi Nagata, Peter I Mackenzie, Hideyuki Yamada, Yuji Ishii
Our previous studies have demonstrated functional protein-protein interactions between cytochrome P450 (CYP) 3A and UDP-glucuronosyltransferase (UGT). However, the role of carbohydrate chains of UGTs in the interaction with CYP is not well understood. To address this issue, we examined whether CYP3A1 modulates the function of UGT2B3 which lacks potential glycosylation sites. We also examined whether the introduction of N-glycosylation to UGT2B3 affects CYP3A-dependent modulation of UGT function. To introduce a potential glycosylation site into UGT2B3, Ser 316 of UGT2B3 was substituted with Asn by site-directed mutagenesis...
2016: Frontiers in Pharmacology
Thuy Tran, Scheyla D V S Siqueira, Heinz Amenitsch, Thomas Rades, Anette Müllertz
The colloidal structures formed during lipolysis of self-emulsifying drug delivery systems (SEDDS) might affect the solubilisation and possibly the absorption of drugs. The aim of the current study is to elucidate the structures formed during the in vitro lipolysis of four SEDDS containing medium-chain glycerides and caprylocaproyl polyoxyl-8 glycerides (Labrasol), with or without monoacyl phosphatidylcholine (MAPC). In situ synchrotron small-angle X-ray scattering (SAXS) was combined with ex situ cryogenic transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS) to elucidate the generated structures...
November 23, 2016: European Journal of Pharmaceutical Sciences
Ryan A Mlynarek, Simon Lee, Asheesh Bedi
The overhead pitching motion is a coordinated sequence of movements that subjects the shoulder to extreme forces. The ultimate goal of this complex, dynamic activity is to generate high ball velocity and accuracy. In doing so, repetitive throwing can cause adaptive and pathologic changes in the thrower's shoulder. This article reviews the relevant shoulder anatomy, the kinetic chain, and throwing mechanics, as well as common shoulder injuries and surgical options for the treating orthopedic surgeon.
February 2017: Hand Clinics
Bruno Bertini, Mario Collura, Jacopo De Nardis, Maurizio Fagotti
We consider the nonequilibrium time evolution of piecewise homogeneous states in the XXZ spin-1/2 chain, a paradigmatic example of an interacting integrable model. The initial state can be thought of as the result of joining chains with different global properties. Through dephasing, at late times, the state becomes locally equivalent to a stationary state which explicitly depends on position and time. We propose a kinetic theory of elementary excitations and derive a continuity equation which fully characterizes the thermodynamics of the model...
November 11, 2016: Physical Review Letters
Aleksandra Tesmar, Dariusz Wyrzykowski, Eva Muñoz, Bogusław Pilarski, Joanna Pranczk, Dagmara Jacewicz, Lech Chmurzyński
The influence of the different side chain residues on the thermodynamic and kinetic parameters for complexation reactions of the Co(2)(+) and Ni(2)(+) ions has been investigated by using the isothermal titration calorimetry (ITC) technique supported by potentiometric titration data. The study was concerned with the 2 common tripodal aminocarboxylate ligands, namely, nitrilotriacetic acid and N-(2-hydroxyethyl) iminodiacetic acid. Calorimetric measurements (ITC) were run in the 2-(N-morpholino)ethanesulfonic acid hydrate (2-(N-morpholino) ethanesulfonic acid), piperazine-N,N'-bis(2-ethanesulfonic acid), and dimethylarsenic acid buffers (0...
November 25, 2016: Journal of Molecular Recognition: JMR
Ye-Jin Kim, Oh-Hoon Kwon
We investigated the dynamics of excited-state proton transfer (ESPT) of photo-amphiprotic 7-hydroxyquinoline (7HQ) in the presence of a hydrogen (H)-bond bridging diol in a polar aprotic medium. The formation of 1 : 1 H-bonded complexes of 7HQ with various diols of different alkane chain lengths was revealed using steady-state electronic spectroscopy. With femtosecond-resolved fluorescence spectroscopy, cyclic H-bonded 1 : 1 complexes were found to undergo facile ESPT from the acidic enol to the basic imine group of 7HQ via the H-bond bridge...
November 24, 2016: Physical Chemistry Chemical Physics: PCCP
Bi F Chang, Chia C Liu, Hsiao Y Chang
BACKGROUND: Adolescent tennis players require sufficient hip and shoulder flexibility to achieve the kinetic chain of a tennis stroke or serve. Hence, the objective of this study is to measure the glenohumeral joint internal and external rotation (IR and ER, respectively) and hip ER range of motion and to compare these parameters between experienced and beginner-level adolescent tennis players. METHODS: Twenty-three adolescent tennis players were divided into experienced (N = 12) and beginner groups (N = 11) on the basis of the adolescent national ranking of the Taiwan Tennis Association...
November 24, 2016: Journal of Sports Medicine and Physical Fitness
Jesús Gálvez, Juan J Gálvez, Pilar García-Peñarrubia
TCR-pMHC interaction is the keystone of the adaptive immune response. This process exhibits an impressive capacity of speed, sensitivity, and discrimination that allows detecting foreign pMHCs at very low concentration among much more abundant self-pMHC ligands. However, and despite over three decades of intensive research, the mechanisms by which this remarkable discrimination and sensitivity is attained remain controversial. In kinetic proofreading mechanisms (KPR), an increase of specificity occurs by reducing the sensitivity...
2016: Frontiers in Immunology
Vito M Butardo, Roslen Anacleto, Sabiha Parween, Irene Samson, Krishna de Guzman, Crisline Mae Alhambra, Gopal Misra, Nese Sreenivasulu
A deeper understanding of the regulation of starch biosynthesis in rice endosperm is crucial in tailoring digestibility without sacrificing grain quality. In this study, significant association peaks on chromosomes 6 and 7 were identified through genome-wide association study (GWAS) of debranched starch structure from grains of a 320 indica rice diversity panel using genotyping data from the high-density rice array. A systems genetics approach that interrelates starch structure data from GWAS to functional pathways from a gene regulatory network identified known and novel genes with high correlation to the proportion of amylose and amylopectin...
November 23, 2016: Plant Physiology
Jean Lehmann
The catalytic site of most enzymes can efficiently handle only one substrate. In contrast, the ribosome is capable of polymerizing at a similar rate at least 20 different kinds of amino acids from aminoacyl-tRNA carriers while using just one catalytic site, the peptidyl-transferase center (PTC). An induced-fit mechanism has been uncovered in the PTC, but a possible connection between this mechanism and the uniform handling of the substrates has not been investigated. We present an analysis of published ribosome structures supporting the hypothesis that the induced-fit eliminates unreactive rotamers predominantly populated for some A-site aminoacyl esters before induction...
November 22, 2016: RNA
Mustafa Ciftci, Yuji Yoshikawa, Yusuf Yagci
A new photoinitiating system for living cationic polymerization of vinyl ethers is reported. In the current approach, visible-light irradiation of dimanganese decacarbonyl (Mn2 (CO)10 ) in the presence of an alkyl bromide results in the formation of carbon-centered radicals. The photochemically generated radicals were then oxidized by diphenyliodonium ions to the corresponding cations. These cations can add vinyl ether monomers, which are then rapidly deactivated by the bromide anions to give α-halide functional end groups...
November 22, 2016: Angewandte Chemie
Bo Qiu, Ming Gong, Qi-Ting He, Pang-Hu Zhou
This paper investigates the protective effect of interleukin-1 receptor antagonist (IL-1Ra) released from hyaluronic acid chitosan (HA-CS) microspheres in a controlled manner on IL-1β-induced inflammation and apoptosis in chondrocytes. The IL-1Ra release kinetics was characterized by an initial burst release, which was reduced to a linear release over eight days. Chondrocytes were stimulated with 10 ng/ml IL-1β and subsequently incubated with HA-CS-IL-1Ra microspheres. The cell viability was decreased by IL-1β, which was attenuated by HA-CS-IL-1Ra microspheres as indicated by an MTT assay...
2016: BioMed Research International
Samy Boulos, Laura Nyström
Polysaccharide degradation mediated by hydroxyl radicals (HO˙) or lytic monooxygenases (LPMOs) is relevant in various biological and industrial processes. Thereby, the Fenton-induced (H2O2/Fe(2+)) oxidation of mixed-linkage (1→3,1→4)-β-d-glucan (BG), a cereal dietary fibre with several well-established health promoting properties, shows potential for modulating BG functionality. The precise identification of oxidation products, however, is impeded by their diversity due to the indiscriminate nature of HO˙, the large molecular weight, and the corresponding low frequency of discrete alterations along the polymer chain...
November 21, 2016: Analyst
Hans Koss, Mark Rance, Arthur G Palmer
Exploration of dynamic processes in proteins and nucleic acids by spin-locking NMR experiments has been facilitated by the development of theoretical expressions for the R1ρ relaxation rate constant covering a variety of kinetic situations. Herein, we present a generalized approximation to the chemical exchange, Rex, component of R1ρ for arbitrary kinetic schemes, assuming the presence of a dominant major site population, derived from the negative reciprocal trace of the inverse Bloch-McConnell evolution matrix...
October 27, 2016: Journal of Magnetic Resonance
Anna Russo, Carlo Diaferia, Sara La Manna, Cinzia Giannini, Teresa Sibillano, Antonella Accardo, Giancarlo Morelli, Ettore Novellino, Daniela Marasco
Nucleophosmin (NPM1) is a multifunctional protein involved in a variety of biological processes including the pathogenesis of several human malignancies and is the most frequently mutated gene in Acute Myeloid Leukemia (AML). To deepen the role of protein regions in its biological activities, lately we reported on the structural behavior of dissected C-terminal domain (CTD) helical fragments. Unexpectedly the H2 (residues 264-277) and H3 AML-mutated regions showed a remarkable tendency to form amyloid-like assemblies with fibrillar morphology and β-sheet structure that resulted as toxic when exposed to human neuroblastoma cells...
November 17, 2016: Biochimica et Biophysica Acta
Chelsea Ledford, Monica McMahon, Ashley Whitesell, Ghalib Khan, Suneel K Kandagatla, Dow P Hurst, Patricia H Reggio, Gregory M Raner
OBJECTIVE: To develop a model for binding and catalysis associated with the stimulation of 4-fluorophenol (4-FP) oxidation in the presence of long chain aldehydes by the enzymatic catalyst, cytochrome P450BM3-F87G. RESULTS: A variation of the Michaeli-Menten kinetic model was employed to describe interactions at the active site of the enzyme, along with computer aided modeling approaches. In addition to the hydroquinone product arising from de-fluorination of 4-FP, a second product (p-fluorocatechol) was also observed and, like the hydroquinone, its rate of formation increased in the presence of the aldehyde...
November 18, 2016: Biotechnology Letters
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