keyword
MENU ▼
Read by QxMD icon Read
search

crystals

keyword
https://www.readbyqxmd.com/read/28088689/syntheses-structures-and-fluorescence-properties-of-three-rare-earth-containing-docosatungstates
#1
Hailou Li, Yajie Liu, Rui Zheng, Xing Ma, Lijuan Chen, Junwei Zhao
Three rare-earth containing docosatungstates Na3H2[RE(H2O)4][RE(H2O)5]2[W22O74H2]·36H2O [RE=Dy(III) (1), Ho(III) (2), Y(III) (3)] have been synthesized by reaction of Na2WO4·2H2O, dimethylamine hydrochloride (DMAHC) and RE(NO3)3·6H2O in the aqueous solution and characterized by elemental analyses, IR spectra, thermogravimetric (TG) analysis, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. 1-3 are isomorphous and each molecular unit consists of a S-shaped docosatungstate [W22O74H2](14-) polyoxoanion with two supporting [RE(H2O)5](3+) cations and one disordered [RE(H2O)4](3+) cation...
January 9, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28088572/bcs-class-iv-drugs-highly-notorious-candidates-for-formulation-development
#2
REVIEW
Rohan Ghadi, Neha Dand
BCS class IV drugs (e.g., amphotericin B, furosemide, acetazolamide, ritonavir, paclitaxel) exhibit many characteristics that are problematic for effective oral and per oral delivery. Some of the problems associated include low aqueous solubility, poor permeability, erratic and poor absorption, inter and intra subject variability and significant positive food effect which leads to low and variable bioavailability. Also, most of the class IV drugs are substrate for P-glycoprotein (low permeability) and substrate for CYP3A4 (extensive pre systemic metabolism) which further potentiates the problem of poor therapeutic potential of these drugs...
January 11, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/28088479/three-dimensional-structure-of-full-length-ntrx-an-unusual-member-of-the-ntrc-family-of-response-regulators
#3
Ignacio Fernández, Irina Cornaciu, Mariela Del Carmen Carrica, Emiko Uchikawa, Guillaume Hoffmann, Rodrigo Sieira, José Antonio Márquez, Fernando A Goldbaum
Bacteria sense and adapt to environmental changes using two-component systems (TCS). These signaling pathways are formed by a histidine kinase (HK) that phosphorylates a response regulator (RR), which finally modulates the transcription of target genes. The bacterium Brucella abortus codes for a TCS formed by the HK NtrY and the RR NtrX that participates in sensing low oxygen tension and in generating an adaptive response. NtrX is a modular protein with REC, AAA+ and DNA binding domains, an architecture that classifies it among the NtrC subfamily of RRs...
January 11, 2017: Journal of Molecular Biology
https://www.readbyqxmd.com/read/28088456/development-of-a-predictive-model-for-the-long-term-stability-assessment-of-drug-in-adhesive-transdermal-films-using-polar-pressure-sensitive-adhesives-as-carrier-matrix
#4
Clémence Chenevas-Paule, Hans-Michael Wolff, Mark Ashton, Martin Schubert, Kalliopi Dodou
Drug crystallization in transdermal drug delivery systems (TDDS) is a critical quality defect. The impact of drug load and hydration on the physical stability of polar (acrylic) drug-in-adhesive (DIA) films was investigated with the objective to identify predictive formulation parameters with respect to drug solubility and long-term stability. Medicated acrylic films were prepared over a range of drug concentrations below and above saturation solubility; and were characterized by FTIR, differential scanning calorimetry (DSC), polarized microscopy and Dynamic Vapor Sorption (DVS) analysis...
January 11, 2017: Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28088447/differential-binding-of-monovalent-cations-to-kcsa-deciphering-the-mechanisms-of-potassium-channel-selectivity
#5
Estefanía Montoya, M Lourdes Renart, A Marcela Giudici, José A Poveda, Asia M Fernández, Andrés Morales, José M González-Ros
This work explores whether the ion selectivity and permeation properties of a model potassium channel, KcsA, could be explained based on ion binding features. Non-permeant Na(+) or Li(+) bind with low affinity (millimolar KD's) to a single set of sites contributed by the S1 and S4 sites seen at the selectivity filter in the KcsA crystal structure. Conversely, permeant K(+), Rb(+), Tl(+) and even Cs(+) bind to two different sets of sites as their concentration increases, consistent with crystallographic evidence on the ability of permeant species to induce concentration-dependent transitions between conformational states (non-conductive and conductive) of the channel's selectivity filter...
January 11, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28088442/the-in-vivo-fate-of-nanocrystals
#6
REVIEW
Yi Lu, Jianping Qi, Xiaochun Dong, Weili Zhao, Wei Wu
There has been significant research interest in, and development of, nanocrystals in recent years for the delivery of poorly water-soluble drugs via various routes. However, there is a common misinterpretation of nanocrystallization as an approach to modulate, and more specifically to enhance, the dissolution of drug crystals. Nevertheless, it is possible for nanocrystals to interact with biological tissues because nanocrystals can survive for a longer duration in vivo compared with XXXX. Therefore, understanding the in vivo fate of nanocrystals and determining its contribution to XXXX is of tremendous significance for optimizing the performance of nanocrystals...
January 11, 2017: Drug Discovery Today
https://www.readbyqxmd.com/read/28088154/vibrational-properties-of-anhydrous-and-partially-hydrated-uranyl-fluoride
#7
M C Kirkegaard, J Langford, J Steill, B Anderson, A Miskowiec
Uranyl fluoride (UO2F2) is a hygroscopic powder with two main structural phases: an anhydrous crystal and a partially hydrated crystal of the same R3¯m symmetry. The formally closed-shell electron structure of anhydrous UO2F2 is amenable to density functional theory calculations. We use density functional perturbation theory (DFPT) to calculate the vibrational frequencies of the anhydrous crystal structure and employ complementary inelastic neutron scattering and temperature-dependent Raman scattering to validate those frequencies...
January 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28088141/determination-of-accurate-mean-bond-lengths-from-radial-distribution-functions
#8
Sergey V Sukhomlinov, Martin H Müser
The mean bond length d between a central atom and its nearest neighbors can be estimated from the position of the first peak in the radial distribution function g(r). However, as we demonstrate here, this estimate does not allow one to deduce temperature-induced changes in d. Instead, skewness has to be included into the analysis, which can be achieved, for example, via the skew normal distribution (SND). Fits to the first peak using the SND give bond length in good agreement with direct measurements of nearest-neighbor distribution functions in crystals as well as with a Voronoi-tessellation based detection of nearest-neighbors in liquids...
January 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28088097/ionic-liquid-pretreatment-of-cassava-residues-for-the-cogeneration-of-fermentative-hydrogen-and-methane
#9
Jun Cheng, Jiabei Zhang, Richen Lin, Jianzhong Liu, Li Zhang, Kefa Cen
An ionic liquid of N-methylmorpholine-N-oxide (NMMO) was used to effectively pretreat cassava residues for the efficient enzymatical hydrolysis and cogeneration of fermentative hydrogen and methane. The reducing sugar yield of enzymolysed cassava residues with NMMO pretreatment improved from 36 to 42g/100g cassava residues. Scanning electron microscopy images revealed the formation of deep grooves (∼4μm wide) and numerous pores in the cassava residues pretreated with NMMO. X-ray diffraction patterns showed that the crystallinity coefficient of NMMO-pretreated cassava residues decreased from 40 to 34...
January 3, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28087839/understanding-the-property-activity-relationships-of-polyhedral-cuprous-oxide-nanocrystals-in-terms-of-reactive-crystallographic-facets
#10
Yanlin Feng, Yun Chang, Xiujuan Sun, Ning Liu, Yan Cheng, Yuqing Feng, Haiyuan Zhang, Xi Li
The property-activity relationship is usually established to understand the toxicity mechanism of nanomaterials. In the present study, different morphological Cu2O nanocrystals, octahedrons, truncated octahedrons, cuboctahedrons, and cubes, were synthesized to precisely tuning the {100} and {111} facet percentages in purpose of systematically investigating the toxicity role of crystallographic facets in BEAS-2B and RAW 264.7 cells. It was found that the toxicity of polyhedral Cu2O nanocrystals was highly dependent on the exposed {100} surface after short-term exposure because {100} facets could produce more reactive oxygen species (ROS) than {111} facets, however, after long-term exposure, their toxicity showed again the correlation with total surface property because toxic copper ions were largely released from the whole nanocrystal surface irrespective of {100} or {111} facet and this copper dissolution caused the collapse of surface crystals and the vanishing of ROS...
January 13, 2017: Toxicological Sciences: An Official Journal of the Society of Toxicology
https://www.readbyqxmd.com/read/28087493/antioxidant-and-antiproliferative-potential-of-biosurfactants-isolated-from-lactobacillus-casei-and-their-anti-biofilm-effect-in-oral-staphylococcus-aureus-strains
#11
Abderrahmen Merghni, Ines Dallel, Emira Noumi, Yassine Kadmi, Hajer Hentati, Samir Tobji, Adel Ben Amor, Maha Mastouri
Biosurfactants also called bioemulsifiers are amphipathic compounds produced by many microorganisms that allow them to exhibit a wide range of biological activities. The aim of this study was to determine the antioxidant and antiproliferative potential of biosurfactants isolated from Lactobacillus casei and to assess their anti-adhesive and anti-biofilm abilities against oral opportunistic Staphylococcus aureus strains. The antioxidant activity of biosurfactant was evaluated using the in vitro scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical...
January 10, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28087472/extract-of-clinopodium-bolivianum-protects-against-e-coli-invasion-of-uroepithelial-cells
#12
Soumitra Mohanty, Witchuda Kamolvit, Silvia Zambrana, Corine Sandström, Eduardo Gonzales, Claes-Göran Östenson, Annelie Braunerf
ETHNOPHARMACOLOGICAL RELEVANCE: Clinopodium bolivianum is a South American plant with anti-inflammatory and anti-infective activities. The increasing antibiotic resistance urges for alternative therapy. Based on its use in traditional medicine, we investigated the effect of C. bolivianum on the ability to defend bladder epithelial cells from E. coli infection. MATERIALS AND METHODS: The extract was analysed by LC-MS. Bladder epithelial cell lines T24 and 5637 and uropathogenic E...
January 10, 2017: Journal of Ethnopharmacology
https://www.readbyqxmd.com/read/28087297/inhibition-of-streptococcal-biofilm-by-hydrogen-water
#13
Jinkyung Kim, Heon-Jin Lee, Su-Hyung Hong
OBJECTIVES: The accumulation of oral bacterial biofilm is the main etiological factor of oral diseases. Recently, electrolyzed hydrogen-rich water (H-water) has been shown to act as an effective antioxidant by reducing oxidative stress. In addition to this general health benefit, H-water has antibacterial activity for disease-associated oral bacteria. However, little is known about the effect of H-water on oral bacterial biofilm. The objective of this study was to confirm the effect of H-water on streptococcal biofilm formation...
January 10, 2017: Journal of Dentistry
https://www.readbyqxmd.com/read/28086264/structural-insights-into-the-redox-sensing-mechanism-of-marr-type-regulator-abfr
#14
Guijie Liu, Xing Liu, Hongjiao Xu, Xichun Liu, Hu Zhou, Zhen Huang, Jianhua Gan, Hao Chen, Lefu Lan, Cai-Guang Yang
As a master redox-sensing MarR-family transcriptional regulator, AbfR participates in oxidative stress responses and virulence regulations in Staphylococcus epidermidis. Here, we present structural insights into the DNA-binding mechanism of AbfR in different oxidation states by determining the X-ray crystal structures of a reduced-AbfR/DNA complex, an overoxidized (Cys13-SO2H and Cys13-SO3H) AbfR/DNA, and 2-disulfide cross-linked AbfR dimer. Together with biochemical analyses, our results suggest that the redox regulation of AbfR-sensing displays two novel features: i) the reversible disulfide modification, but not the irreversible overoxidation, significantly abolishes the DNA-binding ability of the AbfR repressor; ii) either 1-disulfide cross-linked or 2-disulfide cross-linked AbfR dimer is biologically significant...
January 13, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28081482/following-lives-undergoing-change-flux-study-implementation-and-baseline-prevalence-of-drug-use-in-an-online-cohort-study-of-gay-and-bisexual-men-in-australia
#15
Mohamed A Hammoud, Fengyi Jin, Louisa Degenhardt, Toby Lea, Lisa Maher, Jeffrey Grierson, Brent Mackie, Marcus Pastorelli, Colin Batrouney, Nicky Bath, Jack Bradley, Garrett P Prestage
BACKGROUND: Drug use among gay and bisexual men (GBM) is higher than most populations. The use of crystal methamphetamine, erectile dysfunction medication (EDM), and amyl nitrite have been associated with sexual risk behaviour and HIV infection among gay and bisexual men (GBM). OBJECTIVE: This paper describes an online prospective observational study of licit and illicit drug use among GBM and explores baseline prevalence of drug use in this sample. Capturing these data poses challenges as participants are required to disclose potentially illegal behaviours in a geographically dispersed country...
January 9, 2017: International Journal on Drug Policy
https://www.readbyqxmd.com/read/28081148/characterization-of-multi-drug-resistant-enterococcus-faecalis-isolated-from-cephalic-recording-chambers-in-research-macaques-macaca-spp
#16
Stephanie E Woods, Mia T Lieberman, Francois Lebreton, Elise Trowel, César de la Fuente-Núñez, Joanne Dzink-Fox, Michael S Gilmore, James G Fox
Nonhuman primates are commonly used for cognitive neuroscience research and often surgically implanted with cephalic recording chambers for electrophysiological recording. Aerobic bacterial cultures from 25 macaques identified 72 bacterial isolates, including 15 Enterococcus faecalis isolates. The E. faecalis isolates displayed multi-drug resistant phenotypes, with resistance to ciprofloxacin, enrofloxacin, trimethoprim-sulfamethoxazole, tetracycline, chloramphenicol, bacitracin, and erythromycin, as well as high-level aminoglycoside resistance...
2017: PloS One
https://www.readbyqxmd.com/read/28081126/a-pan-lyssavirus-taqman-real-time-rt-pcr-assay-for-the-detection-of-highly-variable-rabies-virus-and-other-lyssaviruses
#17
Ashutosh Wadhwa, Kimberly Wilkins, Jinxin Gao, Rene Edgar Condori Condori, Crystal M Gigante, Hui Zhao, Xiaoyue Ma, James A Ellison, Lauren Greenberg, Andres Velasco-Villa, Lillian Orciari, Yu Li
Rabies, resulting from infection by Rabies virus (RABV) and related lyssaviruses, is one of the most deadly zoonotic diseases and is responsible for up to 70,000 estimated human deaths worldwide each year. Rapid and accurate laboratory diagnosis of rabies is essential for timely administration of post-exposure prophylaxis in humans and control of the disease in animals. Currently, only the direct fluorescent antibody (DFA) test is recommended for routine rabies diagnosis. Reverse-transcription polymerase chain reaction (RT-PCR) based diagnostic methods have been widely adapted for the diagnosis of other viral pathogens, but there is currently no widely accepted rapid real-time RT-PCR assay for the detection of all lyssaviruses...
January 2017: PLoS Neglected Tropical Diseases
https://www.readbyqxmd.com/read/28081112/electronic-states-of-defect-with-impurity-and-infrared-emission-on-black-silicon-prepared-by-an-ns-laser
#18
Zhong-Mei Huang, Wei-Qi Huang, Zui-Min Jiang, Shi-Rong Liu, Xue-Ke Wu, Chao-Jian Qin
It is found that the optimum annealing temperature is about 1000°C for the infrared emission of defect states at room temperature on black silicon (BS) prepared by using a nanosecond-pulsed laser. In addition, it is observed that the suitable annealing time is 6∼8  min at 1000°C for the emission on the BS. The crystallizing proceeding in annealing on the BS can be used to explain the above annealing effect. It is interesting that the emission band becomes intensive and broader on the BS prepared in oxygen atmosphere than that prepared in vacuum in the analysis of photoluminescence spectra, where the electronic states localized at the defects from D1 to D4 doped with oxygen play an important role in the emission with the broader band which are obviously enhanced in the room temperature...
January 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28081088/am-to-pm-conversion-in-a-resonant-microwave-optical-rectification-detector
#19
Brian H Kolner, Lanbing Kang
A LiNbO<sub>3</sub>-loaded microwave cavity pumped with weakly AM-modulated 30 fs optical pulses was used as a platform to investigate AM-to-PM conversion in the optical rectification process. Theoretical treatment of AM-to-PM conversion (i.e., peak-induced electrical phase deviation β<sub>i</sub> due to optical power modulation with index m) suggests that the dominant mechanism is self-group-velocity modulation due to χ<sup>(3)</sup> and cascaded χ<sup>(2)</sup> processes with a value of δ=β<sub>i</sub>/m=-151  dB, linearly dependent on the optical power at intensities of 6×10<sup>10</sup>  W/m<sup>2</sup> in a 40 mm long LiNbO<sub>3</sub> crystal...
January 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28081066/experimental-demonstration-of-pulse-multiplexing-and-beam-combining-of-four-fiber-lasers-by-noncollinear-frequency-conversion-in-an-lbo-crystal
#20
Julijanas Želudevičius, Kęstutis Regelskis, Gediminas Račiukaitis
In this work, we provide proof-of-concept experimental realization of pulse multiplexing and beam combining of four pulsed Yb-doped fiber lasers by noncollinear frequency up-conversion in an LBO crystal. An overall conversion efficiency of 51% and up to 29 W average power in a combined 532 nm beam were achieved. These results correspond to an improvement by a factor of 2 compared to the average power extracted from a single fiber amplifier.
January 15, 2017: Optics Letters
keyword
keyword
34160
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"