Read by QxMD icon Read


Joao Paulo Coelho, José Osío Barcina, Elena Junquera, Emilio Aicart, Gloria Tardajos, Sergio Gómez-Graña, Pablo Cruz-Gil, Cástor Salgado, Pablo Díaz-Núñez, Ovidio Peña-Rodríguez, Andrés Guerrero-Martínez
Amphiphilic nonionic ligands, synthesized with a fixed hydrophobic moiety formed by a thiolated alkyl chain and an aromatic ring, and with a hydrophilic tail composed of a variable number of oxyethylene units, were used to functionalize spherical gold nanoparticles (AuNPs) in water. Steady-state and time-resolved fluorescence measurements of the AuNPs in the presence of α-cyclodextrin (α-CD) revealed the formation of supramolecular complexes between the ligand and macrocycle at the surface of the nanocrystals...
March 16, 2018: Nanomaterials
Matthieu Fumagalli, Julien Berriot, Benoit de Gaudemaris, Anne Veyland, Jean-Luc Putaux, Sonia Molina-Boisseau, Laurent Heux
Rubber materials with well-dispersed fillers and large mechanical reinforcement have been obtained by melt-processing a diene elastomer matrix and tailored nanocellulose powders having both a high specific surface area and a modified interface. Such filler powders with a specific surface area of 180 m2 g-1 and 100 m2 g-1 have been obtained by freeze-drying suspensions of short needle-like cellulose nanocrystals (CNCs) and entangled networks of microfibrillated cellulose (MFC) in tert-butanol/water, respectively...
March 16, 2018: Soft Matter
Jejoong Yoo, Aleksei Aksimentiev
In contrast to ordinary polymers, the vast majority of biological macromolecules adopt highly ordered three-dimensional structures that define their functions. The key to folding of a biopolymer into a unique 3D structure or to an assembly of several biopolymers into a functional unit is a delicate balance between the attractive and repulsive forces that also makes such self-assembly reversible under physiological conditions. The all-atom molecular dynamics (MD) method has emerged as a powerful tool for studies of individual biomolecules and their functional assemblies, encompassing systems of ever increasing complexity...
March 16, 2018: Physical Chemistry Chemical Physics: PCCP
Evgenia N Nikolova, Robyn L Stanfield, Jane Dyson, Peter E Wright
Many eukaryotic transcription factors recognize the epigenetic marker 5-methylcytosine (mC) at CpG sites in DNA. Despite their structural diversity, methyl-CpG-binding proteins (MBPs) share a common mode of recognition of mC methyl groups that involves hydrophobic pockets and weak hydrogen bonds of the CH---O type. The zinc finger protein Kaiso possesses a remarkably high specificity for methylated over unmethylated CpG sites. A key contribution to this specificity is provided by glutamate 535 (E535), which is optimally positioned to form multiple interactions with mCpG, including direct CH---O hydrogen bonds...
March 16, 2018: Biochemistry
Dongni Wu, Shuangying Zhang, Yuyuan Zhao, Ningjian Ao, Seeram Ramakrishna, Liumin He
RADA16-I (Ac-(RADA)4 -CONH2 ) is a widely investigated self-assembling peptide (SAP) in the biomedical field. It can undergo ordered self-assembly to form stable secondary structures, thereby further forming a nanofiber hydrogel. The modification of RADA16-I with functional peptide motifs has become a popular research topic. Researchers aim to exhibit particular biomedical signaling, and subsequently, further expand its applications. However, only a few fundamental reports are available on the influences of the peptide motifs on self-assembly mechanisms of designer functional RADA16-I SAPs...
March 16, 2018: Biomedical Materials
Paween Mahinthichaichan, Robert B Gennis, Emad Tajkhorshid
Cytochrome aa3 is the terminal respiratory enzyme of all eukaryotes and many bacteria and archaea, reducing O2 to water and harnessing the free energy from the reaction to generate the transmembrane electrochemical potential. The diffusion of O2 to the heme-copper catalytic site, which is buried deep inside the enzyme, is the initiation step of the reaction chemistry. Our previous molecular dynamics (MD) study with cytochrome ba3 , a homologous enzyme of cytochrome aa3 in Thermus thermophilus, demonstrated that O2 diffuses from the lipid bilayer to its reduction site through a 25-Å long tunnel inferred by Xe-binding sites detected by X-ray crystallography$ ...
March 16, 2018: Biochemistry
José Andrés Medrano-Félix, Cristóbal Chaidez, Kristina D Mena, María Del Socorro Soto-Galindo, Nohelia Castro-Del Campo
Survival of bacterial pathogens in different environments is due, in part, to their ability to form biofilms. Four wild-type Salmonella enterica strains, two Oranienburg and two Saintpaul isolated from river water and animal feces, were tested for biofilm formation at the air-liquid interface under stressful conditions (pH and salinity treatments such as pH 3, NaCl 4.5 w/v; pH 7, NaCl 4.5 w/v; pH 10, NaCl 4.5 w/v; pH 3, Nacl 0.5 w/v; pH 7, NaCl 0.5 w/v; and pH 10, NaCl 0.5 w/v); Salmonella Typhimurium DT104 was used as a control strain...
March 15, 2018: Environmental Monitoring and Assessment
Gloria Huerta-Ángeles, Kateřina Knotková, Petr Knotek, Ondrej Židek, Martina Brandejsová, Marek Pokorný, Hana Vagnerová, Ipsita Roy, Vladimir Velebný
In this work, a hybrid copolymer consisting of poly(3-hydroxybutyrate) grafted to hyaluronic acid (HA) was synthesised and characterised. Once formed, the P(3HB)-g-HA copolymer was soluble in water allowing a green electrospinning process. The diameters of nanofibres can be tailored by simply varying the Mw of polymer. The optimization of the process allowed to produce fibres of average diameter in the range of 100-150 nm and low polydispersity. The hydrophobic modification has not only increased the fibre diameter, but also the obtained layers were homogenous...
March 15, 2018: Journal of Materials Science. Materials in Medicine
Vaishnavi Rohitkumar Shah, Pardeep K Gupta
PURPOSE: Despite the fact that r-hGH was first approved for use by FDA in 1995 and the conventional dosage form in the market has a limitation of daily subcutaneous injections, there remains a lack of sustained delivery system in the market. Nutropin depot, a long-acting dosage form of r-hGH was approved for marketing by FDA in 1999, however, it was discontinued in 2004. Since then, unabating efforts have been made to develop biodegradable polymer based formulations for r-hGH delivery...
March 15, 2018: Pharmaceutical Research
Tadashi Sugahara, Yuichiro Takamatsu, Avinash Bhadani, Masaaki Akamatsu, Kenichi Sakai, Masahiko Abe, Hideki Sakai
In this study, we synthesize a novel oleic acid-based gemini surfactant with carboxylate headgroups, and study the effect of stereochemistry (anti- vs. syn-) on self-aggregation properties in water. We investigate these properties using phase diagrams, static surface tension, and one-dimensional and two-dimensional nuclear magnetic resonance (NMR) measurements. We find that a phase transition from a hexagonal liquid crystal (H1) phase to a lamellar liquid crystal (Lα) phase occurs at a lower surfactant concentration in the syn form, when compared with the anti form...
March 16, 2018: Physical Chemistry Chemical Physics: PCCP
L S Usmanova, M A Ziganshin, I T Rakipov, N M Lyadov, A E Klimovitskii, T A Mukhametzyanov, A V Gerasimov
Inhalation administration is a promising alternative to the invasive drug delivery methods. The particle size required for ideal drug aerosol preparation is between 1 and 3  μ m. The application of microspherical particles of solid dispersions enhances bioavailability of poorly soluble drugs due to the solubilization. In the present work, the spray drying process of the production of microspherical particles of solid dispersions of polyvinylpyrrolidone K29-32 with model hydrophobic drug, phenacetin, was optimized using the results of DSC, PXRD, and viscometry...
2018: BioMed Research International
Alma Botas, Rosario Pérez-Redondo, Antonio Rodríguez-García, Rubén Álvarez-Álvarez, Paula Yagüe, Angel Manteca, Paloma Liras
ArgR is a well-characterized transcriptional repressor controlling the expression of arginine and pyrimidine biosynthetic genes in bacteria. In this work, the biological role of Streptomyces coelicolor ArgR was analyzed by comparing the transcriptomes of S. coelicolor Δ argR and its parental strain, S. coelicolor M145, at five different times over a 66-h period. The effect of S. coelicolor ArgR was more widespread than that of the orthologous protein of Escherichia coli , affecting the expression of 1544 genes along the microarray time series...
2018: Frontiers in Microbiology
Shuai Zhang, Qinfu Liu, Hongfei Cheng, Feng Gao, Cun Liu, Brian J Teppen
Intercalation is the promising strategy to expand the interlayer region of kaolinite for their further applications. Herein, the adaptive biasing force (ABF) accelerated molecular dynamics simulations were performed to calculate the free energies involved in the kaolinite intercalation by dimethyl sulfoxide (DMSO). Additionally, the classical all atom molecular dynamics simulations were carried out to calculate the interfacial interactions between kaolinite interlayer surfaces and DMSO with the aim at exploring the underlying force that drives the DMSO to enter the interlayer space...
January 2018: Applied Clay Science
Yi Zhang, Melanie Berghaus, Sean Klein, Kelly Jenkins, Siwen Zhang, Scott A McCallum, Joel Morgan, Roland Winter, Doug Barrick, Catherine A Royer
Many repeat proteins contain capping motifs, which serve to shield the hydrophobic core from solvent and maintain structural integrity. While the role of capping motifs in enhancing the stability and structural integrity of repeat proteins is well-documented, their contribution to folding cooperativity is not. Here we examined the role of capping motifs in defining the folding cooperativity of the leucine rich repeat protein, pp32, by monitoring the pressure and urea induced unfolding of an N-cap deletion mutant, pp32-∆N-cap, and a C-cap destabilization mutant pp32-Y131F/D146L, using residue specific NMR and SAXS...
March 12, 2018: Journal of Molecular Biology
Jasmin L Whittaker, Rajkamal Balu, Robert Knott, Liliana de Campo, Jitendra P Mata, Christine Rehm, Anita J Hill, Naba K Dutta, Namita Roy Choudhury
Regenerated Bombyx mori silk fibroin (RSF) is a widely recognized protein for biomedical applications; however, their hierarchical gel structures are poorly understood. In this paper, the hierarchical structure of photocrosslinked RSF and RSF-based hybrid hydrogel systems: (i) RSF/Rec1-resilin and (ii) RSF/poly(N-vinylcaprolactam (PVCL) is reported for the first time using small-angle scattering (SAS) techniques. The structure of RSF in dilute to concentrated solution to fabricated hydrogels were characterized using small angle X-ray scattering (SAXS), small angle neutron scattering (SANS) and ultra-small angle neutron scattering (USANS) techniques...
March 12, 2018: International Journal of Biological Macromolecules
Zelig Chernia, Yoav Tsori
Phase separation in substituted pyridines in water is usually described as an interplay between temperature-driven breakage of hydrogen bonds and the associating interaction of the van der Waals force. In previous quantum-chemical studies, the strength of hydrogen bonding between one water and one pyridine molecules (the 1:1 complex) was assigned a pivotal role. It was accepted that the disassembly of the 1:1 complex at a critical temperature leads to phase separation and formation of the miscibility gap. Yet, for over two decades, notable empirical data and theoretical arguments were presented against that view, thus revealing the need in a revised quantum-mechanical description...
March 14, 2018: Journal of Chemical Physics
Jianguo Li, Roger Beuerman, Chandra Verma
Molecular aggregation plays a significant role in modulating the solubility, permeability, and bioactivity of drugs. The propensity to aggregate depends on hydrophobicity and on molecular shape. Molecular dynamics simulations coupled with enhanced sampling methods are used to explore the early stages of oligomerization of two drug molecules which have a strong aggregation propensity, but with contrasting molecule shapes: the antibiotic ciprofloxacin and the anticancer drug Nutlin-3A. The planar shape of ciprofloxacin induces the formation of stable oligomers at all cluster sizes...
March 14, 2018: Journal of Chemical Physics
Takashi Hoshiba, Chiaki Yoshikawa, Keita Sakakibara
Charged substrates are expected to promote cell adhesion via electrostatic interaction, but it remains unclear how cells adhere to these substrates. Here, initial cell adhesion (< 30 min) was re-examined on charged substrates in serum-containing and serum-free media to distinguish various cell adhesion mechanisms (i.e., electrostatic interaction, hydrophobic interaction, and biological interaction). Cationic and anionic methacrylate copolymers were coated on nonionic non-tissue culture treated polystyrene to create charged substrates...
March 15, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Ande Rostvall, Wen Zhang, Wiebke Dürig, Gunno Renman, Karin Wiberg, Lutz Ahrens, Pablo Gago-Ferrero
This study evaluated the performance of five different sorbents (granular activated carbon (GAC), GAC + Polonite® (GAC + P), Xylit, lignite and sand) for a set of 83 micropollutants (MPs) (pharmaceuticals, perfluoroalkyl substances (PFASs), personal care products, artificial sweeteners, parabens, pesticide, stimulants), together representing a wide range of physicochemical properties. Treatment with GAC and GAC + P provided the highest removal efficiencies, with average values above 97%. Removal rates were generally lower for Xylit (on average 74%) and lignite (on average 68%), although they proved to be highly efficient for a few individual MPs...
March 6, 2018: Water Research
Qiang Wang, Feiyang Liu, Shuang Qi, Ziping Qi, Xiao-E Yan, Beilei Wang, Aoli Wang, Wei Wang, Cheng Chen, Xiaochuan Liu, Zongru Jiang, Zhenquan Hu, Li Wang, Wenchao Wang, Tao Ren, Shanchun Zhang, Cai-Hong Yun, Qingsong Liu, Jing Liu
Through exploration of the non-highly conserved allosteric hydrophobic pocket generated by DFG-out shifting in the inactive conformation, we discovered a highly selective type II PDGFRα kinase inhibitor 15i (CHMFL-PDGFRα-159), which exhibited strong potency against purified PDGFRα (IC50 : 132 nM) but not structurally similar PDGFRβ, ABL, c-KIT and VEGFR2 kinases. In addition, it displayed a high selectivity profile (S score (10) = 0.02) at the concentration of 1 μM among 468 kinases/mutants in the KINOMEscan profiling...
March 12, 2018: European Journal of Medicinal Chemistry
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"