keyword
MENU ▼
Read by QxMD icon Read
search

crystal

keyword
https://www.readbyqxmd.com/read/28222406/leydig-cell-clustering-and-reinke-crystal-distribution-in-relation-to-hormonal-function-in-adult-patients-with-testicular-dysgenesis-syndrome-tds-including-cryptorchidism
#1
Rikke R Soerensen, Trine H Johannsen, Niels E Skakkebaek, Ewa Rajpert-De Meyts
OBJECTIVE: Testicular dysgenesis syndrome (TDS) comprises testicular germ cell cancer, cryptorchidism and some cases of male infertility and hypospadias, which can be linked to impairment of intrauterine gonadal development. Among histological signs of TDS, large Leydig cell (LC) clusters (micronodules) are frequently present. This study aimed to investigate possible associations of LC micronodules with the presence of Reinke crystals and hormonal function of LCs, the latter primarily reflected by serum concentrations of luteinising hormone (LH) and testosterone, in patients with TDS...
October 2016: Hormones: International Journal of Endocrinology and Metabolism
https://www.readbyqxmd.com/read/28222243/studies-on-the-binding-of-modest-modulators-of-the-human-enzyme-sirtuin-6-using-std-nmr
#2
Beatriz E Bolívar, John T Welch
Pyrazinamide (PZA), an essential constituent of short course tuberculosis chemotherapy, binds weakly but selectively to Sirtuin 6 (SIRT6). Despite structural similarities between nicotinamide (NAM), PZA, and pyrazinoic acid (POA), these inhibitors modulate SIRT6 via different mechanisms and binding sites, as suggested by Saturation Transfer Difference (STD) Nuclear Magnetic Resonance (NMR). Available experimental evidence, such as that derived from crystal structures and kinetic experiments, is of only limited utility in the elucidation of the mechanistic details of sirtuin inhibition by NAM or other inhibitors...
February 21, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28221803/effects-of-thickness-on-the-metal-insulator-transition-in-free-standing-vanadium-dioxide-nanocrystals
#3
Mustafa M Fadlelmula, Engin Can Sürmeli, Mehdi Ramezani, Talip Serkan Kasırga
Controlling solid state phase transitions via external stimuli offers rich physics along with possibilities of unparalleled applications in electronics and optics. The well-known metal-insulator transition (MIT) in vanadium dioxide (VO2) is one instance of such phase transitions emerging from strong electronic correlations. Inducing the MIT using electric field has been investigated extensively for the applications in electrical and ultrafast optical switching. However, as the Thomas-Fermi screening length is very short, for considerable alteration in the material's properties with electric field induced MIT, crystals below 10 nm are needed...
February 21, 2017: Nano Letters
https://www.readbyqxmd.com/read/28221799/insoluble-off-pathway-aggregates-as-crowding-agents-during-amyloid-fibril-formation
#4
Rosa Crespo, Eva M Villar-Alvarez, Pablo Taboada, Fernando A Rocha, Ana M Damas, Pedro M Martins
The study of drug candidates for the treatment of amyloidosis and neurodegenerative diseases frequently involves in vitro measurements of amyloid fibril formation. Macromolecular crowding and off-pathway aggregation (OPA) are, by different reasons, two important phenomena affecting the scalability of amyloid inhibitors and their successful application in vivo. On the one hand, the cellular milieu is crowded with macromolecules that drastically increase the effective (thermodynamic) concentration of the amyloidogenic protein...
February 21, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28221788/substituted-2-aminopyrimidines-selective-for-%C3%AE-7-nicotinic-acetylcholine-receptor-activation-and-association-with-acetylcholine-binding-proteins
#5
Katarzyna Kaczanowska, Gisela Andrea Camacho Hernandez, Larissa Bendiks, Larissa Kohs, Jose Manuel Cornejo Bravo, Michal Harel, M G Finn, Palmer Taylor
Through studies with ligand binding to the acetylcholine binding protein (AChBP), we previously identified a series of 4,6 substituted 2-aminopyrimidines that associate with this soluble surrogate of the nicotinic acetylcholine receptor (nAChR) in a cooperative fashion, not seen for classical nicotinic agonists and antagonists. To examine receptor interactions of this structural family on ligand-gated ion channels, we employed HEK cells transfected with cDNA's encoding three requisite receptor subtypes: α7-nAChR, α4β2-nAChR and a serotonin receptor (5-HT3AR), along with a fluorescent reporter...
February 21, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28221786/chemical-trends-in-solid-alkali-pertechnetates
#6
Jamie Weaver, Chuck Z Soderquist, Nancy M Washton, Andrew S Lipton, Paul L Gassman, Wayne W Lukens, Albert A Kruger, Nathalie A Wall, John S McCloy
Insight into the solid-state chemistry of pure technetium-99 ((99)Tc) oxides is required in the development of a robust immobilization and disposal system for nuclear waste stemming from the radiopharmaceutical industry, from the production of nuclear weapons, and from spent nuclear fuel. However, because of its radiotoxicity and the subsequent requirement of special facilities and handling procedures for research, only a few studies have been completed, many of which are over 20 years old. In this study, we report the synthesis of pure alkali pertechnetates (sodium, potassium, rubidium, and cesium) and analysis of these compounds by Raman spectroscopy, X-ray absorption spectroscopy (XANES and EXAFS), solid-state nuclear magnetic resonance (static and magic angle spinning), and neutron diffraction...
February 21, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28221770/the-triple-salt-sr14-ta4n13-tan4-o-a-nitridotantalate-oxide-with-19-fold-rock-salt-superstructure
#7
Matthias Wörsching, Martin Daiger, Constantin Hoch
A new structure motif in nitridometalate chemistry is the tetracatena-nitridotantalate anion [Ta4N13](19-). It occurs in the crystal structure of the triple salt Sr14[Ta4N13][TaN4]O (monoclinic, space group P21/c with a = 15.062(2) Å, b = 7.2484(6) Å, c = 24.266(3) Å, and β = 97.280(10)(o)) together with ortho-tantalate and isolated oxide anions. Synthesis followed a new approach with employment of Sr surplus and reductive conditions aimed at the preparation of subvalent compounds. The new structure type was established on the basis of single-crystal X-ray diffraction data and also Rietveld refinement...
February 21, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28221761/ultrasmall-superbright-neodymium-upconversion-nanoparticles-via-energy-migration-manipulation-and-lattice-modification-808-nm-activated-drug-release
#8
Yan Zhang, Zhongzheng Yu, Jingqiu Li, Yanxiao Ao, Jingwen Xue, Zhiping Zeng, Xiangliang Yang, Timothy Thatt Yang Tan
Nd(3+)-sensitized upconversion nanoparticles are amongst the most promising emerging fluorescent nanotransducers. They are activated by 808 nm irradiation, which features merits such as limited tissue overheating and deeper penetration depth, hence attractive for diagnostic and therapeutic applications. Recent studies indicate that ultrasmall nanoparticles (<10 nm) are potentially more suitable for clinical application due to their favorable biodistribution and safety profiles. However, upconversion nanoparticles in the sub-10 nm range suffer from poor luminescence due to their ultrasmall size and greater proportion of lattice defects...
February 21, 2017: ACS Nano
https://www.readbyqxmd.com/read/28221726/how-the-molecular-packing-affects-the-room-temperature-phosphorescence-in-pure-organic-compounds-ingenious-molecular-design-detailed-crystal-analysis-and-rational-theoretical-calculations
#9
Yujun Xie, Yuwei Ge, Qian Peng, Conggang Li, Qianqian Li, Zhen Li
Long-lived phosphorescence at room temperature (RTP) from pure organic molecules is rare. Recent research reveals various crystalline organic molecules can realize RTP with lifetimes extending to the magnitude of second. There is little research on how molecular packing affecting RTP. Three compounds are designed with similar optical properties in solution, but tremendously different solid emission characteristics. By investigating the molecular packing arrangement in single crystals, it is found that the packing style of the compact face to face favors of long phosphorescence lifetime and high photoluminescence efficiency, with the lifetime up to 748 ms observed in the crystal of CPM ((9H-carbazol-9-yl)(phenyl)methanone)...
February 21, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28221385/ir-spectroscopic-investigations-of-chemical-and-photochemical-reactions-on-metal-oxides-bridging-the-materials-gap
#10
REVIEW
Yuemin Wang, Christof Wöll
In this review, we highlight recent progress (2008-2016) in infrared reflection absorption spectroscopy (IRRAS) studies on oxide powders achieved by using different types of metal oxide single crystals as reference systems. Precise polarization- and azimuth-dependent IRRAS data recorded for single crystal substrates has allowed for fundamental insights into the surface chemistry and photochemistry of numerous probe molecules on various surfaces exposed by three very important metal oxides (ZnO, TiO2, and CeO2)...
February 21, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28221162/antiferromagnetic-spin-cantings-as-a-driving-force-of-ferroelectricity-in-multiferroic-cu-sub-2-sub-oseo-sub-3-sub
#11
Viacheslav Chizhikov, V Dmitrienko
Ferroelectric properties of cubic chiral magnet Cu<sub>2</sub>OSeO<sub>3</sub> can emerge due to the spin noncollinearity induced by antiferromagnetic cantings. The cantings are the result of the Dzyaloshinskii-Moriya interaction and in many ways similar to the ferromagnetic cantings in weak ferromagnets. An expression for the local electric polarization is derived, including terms with gradients of magnetization <b>M</b>(<b>r</b>). When averaged over the crystal the electric polarization has a non-vanishing part associated with the anisotropy of the crystal point group 23...
February 21, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28221144/-may-renal-lithiasis-be-really-prevented-new-trends-and-therapeutic-tools
#12
Félix Grases, Antonia Costa-Bauzá, Rafael M Prieto
Renal calculi are generally formed as a result of the combination of certain factors, some related to urine composition (concentration of lithogenic substances, deficiency of crystallization inhibitors, presence of heterogeneous nucleants) and others with renal morphology and anatomy (urinary tract stasis, low urodynamic efficiency cavities, morpho-anatomic deformations, renal papillary tissue lesions). In fact, the composition, macrostructure and microstructure of the calculus will clearly depend on the factors that have induced it...
January 2017: Archivos Españoles de Urología
https://www.readbyqxmd.com/read/28221139/how-do-stones-form-is-unification-of-theories-on-stone-formation-possible
#13
Victoria Y Bird, Saeed R Khan
There are two basic pathways for formation of calcium based kidney stones. Most idiopathic calcium oxalate (CaOx) stones are formed in association with sub-epithelial plaques of calcium phosphate (CaP), known as Randall's plaques, on renal papillary surfaces. Crystal formation and retention within the terminal collecting ducts, the ducts of Bellini, leading to the formation of Randall's plugs, is the other pathway. Both pathways require supersaturation leading to crystallization, regulated by various crystallization modulators produced in response to changing urinary conditions...
January 2017: Archivos Españoles de Urología
https://www.readbyqxmd.com/read/28221098/ion-transport-by-ameloblasts-during-amelogenesis
#14
A L J J Bronckers
Hypomineralization of developing enamel is associated with changes in ameloblast modulation during the maturation stage. Modulation (or pH cycling) involves the cyclic transformation of ruffle-ended (RE) ameloblasts facing slightly acidic enamel into smooth-ended (SE) ameloblasts near pH-neutral enamel. The mechanism of ameloblast modulation is not clear. Failure of ameloblasts of Cftr-null and anion exchanger 2 ( Ae2)-null mice to transport Cl(-) into enamel acidifies enamel, prevents modulation, and reduces mineralization...
March 2017: Journal of Dental Research
https://www.readbyqxmd.com/read/28221042/on-the-internal-dynamics-of-the-3-pyrroline-n-oxide-ring-in-spin-labeled-proteins
#15
Philipp Consentius, Bernhard Loll, Ulrich Gohlke, Claudia Alings, Carsten Mueller, Robert Müller, Christian Teutloff, Udo Heinemann, Martin Kaupp, Markus C Wahl, Thomas Risse
Site-directed spin labeling is a versatile tool to study structure as well as dynamics of proteins using EPR spectroscopy. Methanethiosulfonate (MTS)-spin labels tethered through a disulfide linkage to an engineered cysteine residue were used in a large number of studies to extract structural as well as dynamic information of the protein from the rotational dynamics of the nitroxide moiety. The ring itself was always considered to be a rigid body. In this contribution, we present a combination of high-resolution X-ray crystallography and EPR spectroscopy of spin-labeled protein single crystals demonstrating that the nitroxide ring inverts fast at ambient temperature, while being characterized by a bent conformation at low temperature...
February 21, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28221038/molecular-and-electronic-structures-of-m2o7-m-mn-tc-re
#16
Keith V Lawler, Bradley C Childs, Daniel S Mast, Kenneth R Czerwinski, Alfred P Sattelberger, Frederic Poineau, Paul M Forster
The molecular and electronic structures of the group 7 heptoxides were investigated by computational methods as both isolated molecules and in the solid-state. The metal-oxygen-metal bending angle of the single molecule increased with increasing atomic number, with Re2O7 preferring a linear structure. Natural bond orbital and localized orbital bonding analyses indicate that there is a three-center covalent bond between the metal atoms and the bridging oxygen, and the increasing ionic character of the bonds favors larger bond angles...
February 21, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28221037/computational-investigation-of-ligand-binding-to-the-peripheral-site-in-cyp3a4-conformational-dynamics-and-inhibitor-discovery
#17
Hanwen Du, Junhao Li, Yingchun Cai, Hongxiao Zhang, Guixia Liu, Yun Tang, Weihua Li
Human cytochrome P450 3A4 (CYP3A4) is a major drug-metabolizing enzyme responsible for the metabolism of ~50% of clinically used drugs and is often involved in drug-drug interactions. It exhibits atypical binding and kinetic behavior towards many ligands. Binding of ligands to CYP3A4 is a complex process. Recent studies from both crystallography and biochemistry suggested the existence of a peripheral ligand-binding site at the enzyme surface. However, the stability of ligand bound at this peripheral site and the possibility of discovering new CYP3A4 ligands based on this site remain unclear...
February 21, 2017: Journal of Chemical Information and Modeling
https://www.readbyqxmd.com/read/28221025/synergistic-effects-of-stabilizing-the-surface-structure-and-lowering-the-interface-resistance-in-improving-the-low-temperature-performances-of-layered-lithium-rich-materials
#18
Shi Chen, Lai Chen, Yitong Li, Yuefeng Su, Yun Lu, Liying Bao, Jing Wang, Meng Wang, Feng Wu
Layered lithium-rich cathode material, Li1.2Ni0.2Mn0.6O2 was successfully synthesized by a sol-gel method followed by coating with different amount of Li3-BO3 (LBO, 1wt %, 3wt %, 5wt %). The effects of LBO coating layer on the structure, morphology and low-temperature (-30 °C) electrochemical properties of these materials are investigated systematically. The morphology, crystal structure and grain size of the Li-rich layered oxide are not essentially changed after surface modification; and according to the TEM results, the Li-B-O coating layer exists as an amorphous layer with a thickness of 5~8 nm when the amount is 3wt %...
February 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28221023/polymorph-dependent-electrogenerated-chemiluminescence-of-low-dimensional-organic-semiconductor-structures-for-sensing
#19
Jianmin Gu, Yahui Gao, Jingxiao Wu, Qing Li, Aixue Li, Wei Zhang, Haiyun Dong, Bin Wen, Faming Gao, Yong Sheng Zhao
A sensitive electrogenerated chemiluminescence (ECL) sensor with organic semiconductor as active materials for detecting trace amounts of molecules have been highly desired. However, the crystal structure responses of the ECL properties of the organic semiconductor materials, that is structure-property relationship, is not clear, which limits the development of the sensitive ECL sensors. Herein, for the first time, we reported a novel concept for molecular stacking arrangement dependent electrogenerated chemiluminescence properties of organic semiconductor rubrene microstructures...
February 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28221007/ionic-colloidal-molding-as-a-biomimetic-scaffolding-strategy-for-uniform-bone-tissue-regeneration
#20
Jian Zhang, Jinpeng Jia, Jimin P Kim, Hong Shen, Fei Yang, Qiang Zhang, Meng Xu, Wenzhi Bi, Xing Wang, Jian Yang, Decheng Wu
Inspired by the highly ordered nanostructure of bone, nanodopant composite biomaterials are gaining special attention for their ability to guide bone tissue regeneration through structural and biological cues. However, bone malformation in orthopedic surgery is a lingering issue, partly due to the high surface energy of traditional nanoparticles contributing to aggregation and inhomogeneity. Recently, carboxyl-functionalized synthetic polymers have been shown to mimic the carboxyl-rich surface motifs of non-collagenous proteins in stabilizing hydroxyapatite and directing intrafibrillar mineralization in-vitro...
February 21, 2017: Advanced Materials
keyword
keyword
39300
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"