keyword
MENU ▼
Read by QxMD icon Read
search

Kinetic chain

keyword
https://www.readbyqxmd.com/read/28810729/thermal-stability-of-organic-monolayers-grafted-to-si-111-insights-from-reaxff-reactive-molecular-dynamics-simulations
#1
Federico A Soria, Weiwei Zhang, Adri C T van Duin, Eduardo Martin Patrito
We used the ReaxFF reactive molecular dynamics simulations to investigate the chemical mechanisms and kinetics of thermal decomposition processes of silicon surfaces grafted with different organic molecules via Si-C bonds at atomistic level. In this work, we considered the Si(111) surface grafted with n-alkyl (ethyl, propyl, pentyl and decyl) layers in 50 % coverage and Si-CH3, Si-CCCH3 and Si-CHCHCH3 layers in full coverage. Si radicals primarily formed by the homolytic cleavage of Si-C bonds play a key role in the dehydrogenation processes that lead to the decomposition of the monolayers...
August 16, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28809813/molecular-mechanisms-underlying-inhibitory-binding-of-alkylimidazolium-ionic-liquids-to-laccase
#2
Jianliang Sun, Hao Liu, Wenping Yang, Shicheng Chen, Shiyu Fu
Water-miscible alkylimidazolium ionic liquids (ILs) are "green" co-solvents for laccase catalysis, but generally inhibit enzyme activity. Here, we present novel insights into inhibition mechanisms by a combination of enzyme kinetics analysis and molecular simulation. Alkylimidazolium cations competitively bound to the TI Cu active pocket in the laccase through hydrophobic interactions. Cations with shorter alkyl chains (C₂~C₆) entered the channel inside the pocket, exhibiting a high compatibility with laccase (competitive inhibition constant Kic = 3...
August 15, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28806711/the-potential-of-an-automated-system-to-identify-the-upper-limb-component-of-a-controlled-sitting-posture
#3
María B Sánchez, Ian Loram, John Darby, Paul Holmes, Penelope B Butler
Full trunk control in sitting is demonstrated only when the head-trunk are aligned and upper limbs remain free of contact from mechanical support. These components represent a Controlled Kinetic Chain and can be evaluated in people with neuromotor disability using the Segmental Assessment of Trunk Control (SATCo) when a therapist provides manual trunk support at different segmental levels. However, the SATCo, as with other clinical assessments of control, is subjective. The SATCo was translated to objective rules relating the position of the hands and elbows to the head-trunk and then tested to determine the extent to which this automated objective method replicated the clinical judgement...
August 8, 2017: Gait & Posture
https://www.readbyqxmd.com/read/28806086/role-of-electrostatics-in-protein-rna-binding-the-global-vs-the-local-energy-landscape
#4
Zhaleh Ghaemi, Irisbel Guzman, David Gnutt, Zaida Luthey-Schulten, Martin Gruebele
U1A protein - stem loop 2 RNA association is a basic step in the assembly of the spliceosomal U1 small nuclear ribonucleoprotein. Long-range electrostatic interactions due to the positive charge of U1A are thought to provide high binding affinity for the negatively charged RNA. Short range interactions, such as hydrogen bonds and contacts between RNA bases and protein side chains, favor a specific binding site. Here, we propose that electrostatic interactions are as important as local contacts in biasing the protein-RNA energy landscape towards a specific binding site...
August 14, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28805849/topology-of-polymer-chains-under-nanoscale-confinement
#5
Vahid Satarifard, Maziar Heidari, Samaneh Mashaghi, Sander J Tans, Mohammad Reza Ejtehadi, Alireza Mashaghi
Spatial confinement limits the conformational space accessible to biomolecules but the implications for bimolecular topology are not yet known. Folded linear biopolymers can be seen as molecular circuits formed by intramolecular contacts. The pairwise arrangement of intra-chain contacts can be categorized as parallel, series or cross, and has been identified as a topological property. Using molecular dynamics simulations, we determine the contact order distributions and topological circuits of short semi-flexible linear and ring polymer chains with a persistence length of lp under a spherical confinement of radius Rc...
August 14, 2017: Nanoscale
https://www.readbyqxmd.com/read/28805094/how-balance-task-specific-training-contributes-to-improving-physical-function-in-older-subjects-undergoing-rehabilitation-following-hip-fracture-a-randomized-controlled-trial
#6
Marco Monticone, Emilia Ambrosini, Roberto Brunati, Antonio Capone, Giulia Pagliari, Claudio Secci, Giovanni Zatti, Simona Ferrante
OBJECTIVE: To evaluate the efficacy of a rehabilitation programme including balance task-specific training in improving physical function, pain, activities of daily living (ADL), balance and quality of life in subjects after a hip fracture. DESIGN: Randomized controlled trial. SUBJECTS: A total of 52 older subjects selected for internal fixation due to extra-capsular hip fracture were randomized to be included in an experimental ( n = 26) and control group ( n = 26)...
August 1, 2017: Clinical Rehabilitation
https://www.readbyqxmd.com/read/28805084/covalent-immobilisation-of-transglutaminase-stability-and-applications-in-protein-pegylation
#7
Antonella Grigoletto, Anna Mero, Hiroki Yoshioka, Oddone Schiavon, Gianfranco Pasut
Microbial transglutaminase enzyme (mTGase) is an extremely useful enzyme that is increasingly employed in the food and pharmaceutical industries and as a tool for protein modification and tagging. The current study describes how we immobilised mTGase (iTGase) on a solid support to improve its stability during the PEGylation process by which polyethylene glycol chains are attached to protein and peptide drugs. When the enzyme was immobilised at the N-terminal sequence on agarose beads, it retained more than 53% of its starting activity...
August 13, 2017: Journal of Drug Targeting
https://www.readbyqxmd.com/read/28802667/different-approaches-to-modeling-analysis-of-mitochondrial-swelling
#8
REVIEW
Sabzali Javadov, Xavier Chapa-Dubocq, Vladimir Makarov
Mitochondria are critical players involved in both cell life and death through multiple pathways. Structural integrity, metabolism and function of mitochondria are regulated by matrix volume due to physiological changes of ion homeostasis in cellular cytoplasm and mitochondria. Ca(2+) and K(+) presumably play a critical role in physiological and pathological swelling of mitochondria when increased uptake (influx)/decreased release (efflux) of these ions enhances osmotic pressure accompanied by high water accumulation in the matrix...
August 9, 2017: Mitochondrion
https://www.readbyqxmd.com/read/28801048/the-key-role-of-glutamate-172-in-the-mechanism-of-type-ii-nadh-quinone-oxidoreductase-of-staphylococcus-aureus
#9
Filipe M Sousa, Filipa V Sena, Ana P Batista, Diogo Athayde, José A Brito, Margarida Archer, A Sofia F Oliveira, Cláudio M Soares, Teresa Catarino, Manuela M Pereira
Type II NADH:quinone oxidoreductases (NDH-2s) are membrane bound enzymes that deliver electrons to the respiratory chain by oxidation of NADH and reduction of quinones. In this way, these enzymes also contribute to the regeneration of NAD(+), allowing several metabolic pathways to proceed. As for the other members of the two-Dinucleotide Binding Domains Flavoprotein (tDBDF) superfamily, the enzymatic mechanism of NDH-2s is still little explored and elusive. In this work we addressed the role of the conserved glutamate 172 (E172) residue in the enzymatic mechanism of NDH-2 from Staphylococcus aureus...
August 8, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28783606/photosensitized-oxidation-of-nicotinamide-adenine-dinucleotide-by-diethoxyphosphorus-v-tetraphenylporphyrin-and-its-fluorinated-derivative-possibility-of-chain-reaction
#10
Kazutaka Hirakawa, Atsushi Murata
Water-soluble porphyrins, diethoxyphosphorus(V)tetraphenylporphyrin (EtP(V)TPP) and its fluorinated analogue (FEtP(V)TPP), decreased the typical absorption around 340nm of nicotinamide adenine dinucleotide (NADH) under visible light irradiation, indicating oxidative decomposition. A singlet oxygen quencher, sodium azide, and a triplet quencher, potassium iodide, slightly inhibited photosensitized NADH oxidation. However, these inhibitory effects were very small. Furthermore, the fluorescence lifetime of these P(V)porphyrins was decreased by NADH, suggesting the contribution of electron transfer to the singlet excited (S1) state of P(V)porphyrin...
July 31, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28783007/influence-of-the-chain-length-of-surfactant-in-the-modification-of-zeolites-and-clays-removal-of-atrazine-from-water-solutions
#11
Helen Paola Toledo-Jaldin, Alien Blanco-Flores, Víctor Sánchez-Mendieta, Osnieski Martín-Hernández
Removal potentials of a surfactant modified zeolite (SMZ) and clay (SMC) for atrazine adsorption were evaluated. Materials were modified with hexadecyl trimethyl ammonium bromide (HDTMA) and benzyl octadecyl dimethyl ammonium chloride (BODA) considering the critical miscelar concentration (CMC) of each one (0.94 and 0.041 meq/L, respectively). The influence of the surfactant was analyzed in detail, particularly the formation of surfactant layers (complete or partial) connected with the length of the surfactant tail (16 and 18 methyl groups or number of carbons in the chain)...
August 7, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28781720/mitochondrial-respiration-in-human-colorectal-and-breast-cancer-clinical-material-is-regulated-differently
#12
Andre Koit, Igor Shevchuk, Lyudmila Ounpuu, Aleksandr Klepinin, Vladimir Chekulayev, Natalja Timohhina, Kersti Tepp, Marju Puurand, Laura Truu, Karoliina Heck, Vahur Valvere, Rita Guzun, Tuuli Kaambre
We conducted quantitative cellular respiration analysis on samples taken from human breast cancer (HBC) and human colorectal cancer (HCC) patients. Respiratory capacity is not lost as a result of tumor formation and even though, functionally, complex I in HCC was found to be suppressed, it was not evident on the protein level. Additionally, metabolic control analysis was used to quantify the role of components of mitochondrial interactosome. The main rate-controlling steps in HBC are complex IV and adenine nucleotide transporter, but in HCC, complexes I and III...
2017: Oxidative Medicine and Cellular Longevity
https://www.readbyqxmd.com/read/28778053/release-behavior-and-signaling-effect-of-vitamin-d3-in-layered-double-hydroxides-hydroxyapatite-gelatin-bone-tissue-engineering-scaffold-an-in-vitro-evaluation
#13
Fateme Fayyazbakhsh, Mehran Solati-Hashjin, Abbas Keshtkar, Mohammad Ali Shokrgozar, Mohammad Mehdi Dehghan, Bagher Larijani
Incorporating the controlled release of vitamin D3 (VD3) into biodegradable porous scaffolds is a new approach to equipping multifunctional therapeutics for osteoporosis. The current investigation involves the encapsulation of VD3 into gelatin through the one-step desolvation method. The layered double hydroxides-hydroxyapatite nanocomposite (LDH-HAp) and pure LDH were combined with the gelatin-VD3 complex to reinforce the porous biodegradable structure and enhance the biological response. Afterwards, glutaraldehyde was used to form crosslinks within the gelatin chains...
July 3, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28771959/antibacterial-activity-and-cytotoxycity-of-gelatine-conjugated-lysine-based-peptides
#14
Maja Kaisersberger Vincek, Amram Mor, Selestina Gorgieva, Vanja Kokol
The effect of the coupling approach (chemical by using carbodiimide chemistry, and enzymatic by using transglutaminase) of a hydrophilic ε-poly-L-lysine (εPL) and a structurally-hydrophobic oligo-acyl-lysyl (OAK) to a gelatine (GEL) macromolecule, and their antibacterial activity against Gram-negative E. coli and Gram-positive S. aureus bacteria, as well as cytotoxicity to human osteoblast cells was studied as potential macromolecules for biomedical applications. Different spectroscopic (ultraviolet-visible, infrared, fluorescence, and electron paramagnetic resonance) and separation (size-exclusion chromatography and capillary zone electrophoresis) techniques, as well as zeta-potential analysis were performed to confirm the εPL/OAK covalent coupling and to determine their amount and orientation of the immobilization...
August 2, 2017: Journal of Biomedical Materials Research. Part A
https://www.readbyqxmd.com/read/28766935/poly-ester-amide-s-from-poly-ethylene-terephthalate-waste-for-enhancing-bone-regeneration-and-controlled-release
#15
Janeni Natarajan, Giridhar Madras, Kaushik Chatterjee
The present study elucidates the facile synthesis and exceptional properties of a family of novel poly(ester amide)s (PEAs) based on bis(2-hydroxy ethylene) terephthalamide that was obtained from the poly(ethylene terephthalate) waste. Fourier transform infrared and (1)H NMR were used to verify the presence of ester and amide in the polymer backbone. Differential scanning calorimetry data showed that the glass transition temperature decreased with as the chain length of dicarboxylic acids increased. Dynamic mechanical analysis and contact angle studies proved that the modulus values and hydrophobicity increased with as the chain lengths of dicarboxylic acids increased...
August 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28766626/kinetic-control-in-the-temperature-dependent-sequential-growth-of-surface-confined-supramolecular-copolymers
#16
Sabrina Engel, Daniel Spitzer, Leona Lucas Rodrigues, Eva-Corinna Fritz, David Straßburger, Monika Schönhoff, Bart Jan Ravoo, Pol Besenius
We report the sequential growth of supramolecular copolymers on gold surfaces, using oppositely charged dendritic peptide amphiphiles. By including water-solubilising thermoresponsive chains in the monomer design, we observed non-linear effects in the temperature-dependent sequential growth. The step-wise copolymerisation process is characterised using temperature dependent SPR and QCM-D measurements. At higher temperatures, dehydration of peripheral oligoethylene glycol chains supports copolymer growth due to more favourable comonomer interactions...
August 2, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28766168/pre-and-post-prandial-expression-of-genes-involved-in-lipid-metabolism-at-the-end-of-the-overfeeding-period-of-mule-ducks
#17
Tavernier Annabelle, Ricaud Karine, Bernadet Marie-Dominique, Gontier Karine, Davail Stéphane
In palmipeds, overfeeding leads to hepatic steatosis, also called "foie gras" which is the result of many metabolic mechanisms. In order to understand these mechanisms, we decided to measure the expression of genes implicated in lipid metabolism during 12 hours (h) following the last meal of the overfeeding period. We have shown that there is a precocious expression (within 2 h) of fatty acid synthase and acyl CoA synthetase long-chain 1 in liver and muscle of mule ducks in addition with a later peak. Furthermore, di-acyl glycerol acyl transferase presents the highest induction of expression in liver and it is overexpressed quite a long time, positioning this enzyme as a key factor in hepatic steatosis...
August 1, 2017: Molecular and Cellular Biochemistry
https://www.readbyqxmd.com/read/28763201/tracking-reactive-water-and-hydrogen-bonding-networks-in-photosynthetic-oxygen-evolution
#18
Bridgette A Barry, Udita Brahmachari, Zhanjun Guo
In oxygenic photosynthesis, photosystem II (PSII) converts water to molecular oxygen through four photodriven oxidation events at a Mn4CaO5 cluster. A tyrosine, YZ (Y161 in the D1 polypeptide), transfers oxidizing equivalents from an oxidized, primary chlorophyll donor to the metal center. Calcium or its analogue, strontium, is required for activity. The Mn4CaO5 cluster and YZ are predicted to be hydrogen bonded in a water-containing network, which involves amide carbonyl groups, amino acid side chains, and water...
August 1, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28762417/the-recent-achievements-of-redox-neutral-radical-c-c-cross-coupling-enabled-by-visible-light
#19
Jin Xie, Hongming Jin, A Stephen K Hashmi
Visible-light photoredox catalysis has been esteemed as one sustainable and attractive synthetic tool. In the past four years, a new yet challenging trend, visible-light-driven redox-neutral radical C-C cross-coupling involving putative radical intermediates, has been booming rapidly. Its advent brings a powerful platform to achieve non-classical C-C connections, and should lead to fundamental changes in retrosynthetic analysis. In this tutorial review, we highlight the recent achievements of visible-light-mediated redox-neutral radical C(sp(3))-C(sp(2)), C(sp(3))-C(sp), and C(sp(3))-C(sp(3)) bond formation, opening a new window for C-C cross-coupling through the photoredox electron shuttling cycle between two coupling partners...
August 1, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28762090/human-deiminases-isoforms-substrate-specificities-kinetics-and-detection
#20
Bushra Amin, Wolfgang Voelter
Peptidylarginine deiminase (PAD) enzymes are of enormous interest in biomedicine. They catalyze the conversion of a positively-charged guanidinium at an arginine side chain into a neutral ureido group. As a result of this conversion, proteins acquire the non-ribosomally encoded amino acid "citrulline". This imposes critical influences on the structure and function of the target molecules. In multiple sclerosis, myelin hyper-citrullination promotes demyelination by reducing its compaction and triggers auto-antibody production...
2017: Progress in the Chemistry of Organic Natural Products
keyword
keyword
40854
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"