keyword
MENU ▼
Read by QxMD icon Read
search

Endo barrier

keyword
https://www.readbyqxmd.com/read/28920694/gold-catalyzed-synthesis-of-1-indol-3-yl-carbazoles-selective-1-2-alkyl-vs-1-2-vinyl-migration
#1
Anisley Suárez, Samuel Suárez-Pantiga, Olalla Nieto-Faza, Roberto Sanz
Gold(III)-catalyzed cycloisomerization of α-bis(indol-3-yl)methyl alkynols selectively affords 1-(indol-3-yl)carbazoles, in a transformation that takes place through a selective 1,2-alkyl vs 1,2-vinyl migration step in the vinyl-gold intermediate generated from the initial 5-endo-spirocyclization. The reaction proceeds well with either tertiary or secondary starting alkynols as well as with a wide variety of alkyne substituents. The key role of the other indol-3-yl substituent for the unexpected selectivity in the 1,2 rearrangement has also been supported by DFT calculations that reveal a low barrier, two-step mechanism in the alkyl migration path where the second indole significantly stabilizes a carbocationic intermediate...
September 18, 2017: Organic Letters
https://www.readbyqxmd.com/read/28862433/role-of-ligand-protonation-in-dihydrogen-evolution-from-a-pentamethylcyclopentadienyl-rhodium-catalyst
#2
Samantha I Johnson, Harry B Gray, James D Blakemore, William A Goddard
Recent work has shown that Cp*Rh(bpy) [Cp* = pentamethylcyclopentadienyl, bpy = 2,2'- bipyridine] undergoes endo protonation at the [Cp*] ligand in the presence of weak acid (Et3NH(+); pKa = 18.8 in MeCN). Upon exposure to stronger acid (e.g., DMFH(+); pKa = 6.1), hydrogen is evolved with unity yield. Here, we study the mechanisms by which this catalyst evolves dihydrogen using density functional theory (M06) with polarizable continuum solvation. The calculations show that the complex can be protonated by weak acid first at the metal center with a barrier of 3...
September 1, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28846411/rationalization-of-benzazole-2-carboxylate-versus-benzazine-3-one-benzazine-2-3-dione-selectivity-switch-during-cyclocondensation-of-2-aminothiophenols-phenols-anilines-with-1-2-biselectrophiles-in-aqueous-medium
#3
Tejas M Dhameliya, Sumit S Chourasiya, Eshan Mishra, Pradeep S Jadhavar, Prasad V Bharatam, Asit K Chakraborti
The cyclocondensation reaction of 2-aminothiophenols with 1,2-biselectrophiles such as ethyl glyoxalate and diethyl oxalate in aqueous medium leads to the formation of benzothiazole-2-carboxylates via the 5-endo-trig process contrary to Baldwin's rule. On the other hand, the reaction of 2-aminophenols/anilines produced the corresponding benzazine-3-ones or benzazine-2,3-diones via the 6-exo-trig process in compliance with Baldwin's rule. The mechanistic insights of these cyclocondensation reactions using the hard-soft acid-base principle, quantum chemical calculations (density functional theory), and orbital interaction studies rationalize the selectivity switch of benzothiazole-2-carboxylates versus benzazine-3-ones/benzazine-2,3-diones...
September 15, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28846134/mineral-trioxide-aggregate-and-other-bioactive-endodontic-cements-an-updated-overview-part-ii-other-clinical-applications-and-complications
#4
REVIEW
M Torabinejad, M Parirokh, P M H Dummer
Mineral trioxide aggregate (MTA) is a dental material used extensively for vital pulp therapy (VPT), scaffold cover during regenerative endodontic procedures, apical barrier in teeth with necrotic pulps and open apices, perforation repair, and root canal filling and root-end filling during surgical endodontics. A number of bioactive endodontic cements (BECs) have recently been introduced to the market. Most of these materials had calcium and silicate in their compositions; however, the bioactivity is the common property of these cements...
August 28, 2017: International Endodontic Journal
https://www.readbyqxmd.com/read/28842335/concurrently-suppressing-multidrug-resistance-and-metastasis-of-breast-cancer-by-co-delivery-of-paclitaxel-and-honokiol-with-ph-sensitive-polymeric-micelles
#5
Ziqi Wang, Xinru Li, Dishi Wang, Yang Zou, Xiaoyou Qu, Chuyu He, Yunqiang Deng, Yao Jin, Yuanhang Zhou, Yanxia Zhou, Yan Liu
To concurrently suppress multidrug resistance (MDR) and metastasis of breast cancer cells, paclitaxel (PTX) and honokiol (HNK) were coencapsulated into pH-sensitive polymeric micelles based on poly(2-ethyl-2-oxazoline)-poly(D, L-lactide) (PEOz-PLA). The physicochemical properties of dual drug-loaded PEOz-PLA micelles were characterized in size, drug loading and in vitro release. The efficiency of MDR reversal for the micelles was testified by synergetic enhancement of cytotoxicity and uptake by MCF-7/ADR cells...
August 22, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28819070/claudin-5-binders-enhance-permeation-of-solutes-across-the-blood-brain-barrier-in-a-mammalian-model
#6
Yosuke Hashimoto, Keisuke Shirakura, Yoshiaki Okada, Hiroyuki Takeda, Kohki Endo, Maki Tamura, Akihiro Watari, Yoshifusa Sadamura, Tatsuya Sawasaki, Takefumi Doi, Kiyohito Yagi, Masuo Kondoh
A current bottleneck in the development of central nervous system (CNS) drugs is the lack of drug delivery systems targeting the CNS. The intercellular space between endothelial cells of the blood brain barrier (BBB) is sealed by complex protein-based structures called tight junctions (TJs). Claudin-5, a tetra-transmembrane protein is a key component of the TJ seal that prevents the paracellular diffusion of drugs into the CNS. In the present study, to investigate whether CLDN-5 binders can be used for delivery of drugs to the CNS, we generated monoclonal antibodies specific to the extracellular domains of CLDN-5...
August 17, 2017: Journal of Pharmacology and Experimental Therapeutics
https://www.readbyqxmd.com/read/28813441/cross-over-endocytosis-of-claudins-is-mediated-by-interactions-via-their-extracellular-loops
#7
Nora Gehne, Agathe Lamik, Martin Lehmann, Reiner F Haseloff, Anuska V Andjelkovic, Ingolf E Blasig
Claudins (Cldns) are transmembrane tight junction (TJ) proteins that paracellularly seal endo- and epithelial barriers by their interactions within the TJs. However, the mechanisms allowing TJ remodeling while maintaining barrier integrity are largely unknown. Cldns and occludin are heterophilically and homophilically cross-over endocytosed into neighboring cells in large, double membrane vesicles. Super-resolution microscopy confirmed the presence of Cldns in these vesicles and revealed a distinct separation of Cldns derived from opposing cells within cross-over endocytosed vesicles...
2017: PloS One
https://www.readbyqxmd.com/read/28766656/amide-rotation-trajectories-probed-by-symmetry
#8
Vladimir Kubyshkin, Nediljko Budisa
Amide rotation of peptidyl-prolyl fragments is an important factor in backbone structure organization of proteins. Computational studies have indicated that this rotation preferentially proceeds through a defined transition-state structure (syn/exo). Here, we complement the computational findings by determining the amide bond rotation barriers for derivatives of the two symmetric proline analogues, meso and racemic pyrrolidine-2,5-dicarboxylic acids. The rotations around these residues represent syn/exo-syn/exo and anti/endo-syn/exo hybrid transition states for the meso and racemic diastereomer, respectively...
August 16, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28762267/charge-reversible-multifunctional-hpma-copolymers-for-mitochondrial-targeting
#9
Fengling Wang, Wei Sun, Lian Li, Lijia Li, Yuanyuan Liu, Zhi-Rong Zhang, Yuan Huang
Mitochondrial-oriented delivery of anticancer drugs has been considered as a promising strategy to improve the antitumor efficiency of chemotherapeutics. However, the physiological and biological barriers from the injection site to the final mitochondrial action site remain great challenges. Herein, a novel mitochondrial-targeted multifunctional nanocomplex based on N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers (MPC) is designed to enhance drug accumulation in mitochondria. MPC possesses various functions such as extracellular pH response, superior cellular uptake, lysosomal escape, and mitochondrial targeting...
August 11, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28761156/aggravation-of-collagen-induced-arthritis-by-orally-administered-porphyromonas-gingivalis-through-modulation-of-the-gut-microbiota-and-gut-immune-system
#10
Keisuke Sato, Naoki Takahashi, Tamotsu Kato, Yumi Matsuda, Mai Yokoji, Miki Yamada, Takako Nakajima, Naoki Kondo, Naoto Endo, Reiko Yamamoto, Yuichiro Noiri, Hiroshi Ohno, Kazuhisa Yamazaki
Porhyromonas gingivalis, a causative bacterium of periodontitis, is implicated in the etiology of rheumatoid arthritis (RA), mainly because of expressing peptidyl arginine deiminase (PAD) that generates RA-related autoantigens. However, compared with other periodontopathic bacteria, the precise role of P. gingivalis in RA is largely unknown. We found that orally administered P. gingivalis changed the gut microbiome with concomitant elevation of serum endotoxin and inflammatory markers, and impairment of the gut barrier function...
July 31, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28744742/the-primary-result-of-prospective-randomized-multicenter-trial-of-new-spray-type-bio-absorbable-adhesion-barrier-system-tcd-11091-against-postoperative-adhesion-formation
#11
Takeshi Suto, Masahiko Watanabe, Takeshi Endo, Koji Komori, Masayuki Ohue, Yukihide Kanemitsu, Masaaki Itou, Yasumasa Takii, Toshimasa Yatsuoka, Manabu Shiozawa, Tetsushi Kinugasa, Hideki Ueno, Tadatoshi Takayama, Tadahiko Masaki, Hiroyuki Masuko, Hisanaga Horie, Masafumi Inomata
BACKGROUND: Postoperative adhesions are the major cause of postoperative complications including intestinal obstruction, infertility, and chronic pelvic pain. In order to reduce postoperative adhesions, Terumo Corporation (Tokyo, Japan) has developed an adhesion barrier system (TCD-11091) which is easy to use at the treatment site in various surgical procedures including laparoscopic surgeries. We conducted a prospective randomized single-blind study in patients who underwent laparotomy with ileostomy...
July 25, 2017: Journal of Gastrointestinal Surgery: Official Journal of the Society for Surgery of the Alimentary Tract
https://www.readbyqxmd.com/read/28675177/norrin-induced-frizzled4-endocytosis-and-endo-lysosomal-trafficking-control-retinal-angiogenesis-and-barrier-function
#12
Chi Zhang, Maria B Lai, Lavan Khandan, Lindsey A Lee, Zhe Chen, Harald J Junge
Angiogenesis and blood-brain barrier formation are required for normal central nervous system (CNS) function. Both processes are controlled by Wnt or Norrin (NDP) ligands, Frizzled (FZD) receptors, and β-catenin-dependent signalling in vascular endothelial cells. In the retina, FZD4 and the ligand NDP are critical mediators of signalling and are mutated in familial exudative vitreoretinopathy. Here, we report that NDP is a potent trigger of FZD4 ubiquitination and induces internalization of the NDP receptor complex into the endo-lysosomal compartment...
July 4, 2017: Nature Communications
https://www.readbyqxmd.com/read/28661127/challenges-in-dna-delivery-and-recent-advances-in-multifunctional-polymeric-dna-delivery-systems
#13
Bingyang Shi, Meng Zheng, Wei Tao, Roger Chung, Dayong Jin, Dariush Ghaffari, Omid C Farokhzad
After more than 20 years of intensive investigations, gene therapy has become one of the most promising strategies for treating genetic diseases. However, the lack of ideal delivery systems has limited the clinical realization of gene therapy's tremendous potential, especially for DNA-based gene therapy. Over the past decade, considerable advances have been made in the application of polymer-based DNA delivery systems for gene therapy, especially through multifunctional systems. The core concept behind multifunctional polymeric DNA delivery systems is to endow one single DNA carrier, via materials engineering and surface modification, with several active functions, e...
July 14, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28605408/casparian-bands-and-suberin-lamellae-in-exodermis-of-lateral-roots-an-important-trait-of-roots-system-response-to-abiotic-stress-factors
#14
Edita Tylová, Eva Pecková, Zuzana Blascheová, Aleš Soukup
Background and Aims: Root absorptive characteristics rely on the presence of apoplastic barriers. However, little is known about the establishment of these barriers within a complex root system, particularly in a major portion of them - the lateral roots. In Zea mays L., the exodermis differentiates under the influence of growth conditions. Therefore, the species presents a suitable model to elucidate the cross-talk among environmental conditions, branching pattern and the maturation of barriers within a complex root system involved in the definition of the plant-soil interface...
July 1, 2017: Annals of Botany
https://www.readbyqxmd.com/read/28593693/double-gold-activation-of-1-ethynyl-2-phenylethynyl-benzene-toward-5-exo-dig-and-6-endo-dig-cyclization-reactions
#15
Nery Villegas-Escobara, Mie Hojer Vilhelmsen, Soledad Gutierrez-Oliva, A Stephen K Hashmi, Alejandro Toro-Labbé
In this work, a detailed characterization of the ring closure mechanism of EPB (1-ethynyl-2-(phenylethynyl)benzene) toward the 5-exo-dig and 6-endo-dig cyclization reactions catalyzed by two Au-NHC moieties was carried out. It was found that the 5-exo-dig cyclization takes place with a slightly lower activation barrier and larger exothermicity compared to that of the 6-endo-dig cyclization, in Agreement with the available experimental data. A phenomenological partition (structural and electronic) for rate constants computed using transition state theory and the reaction force analysis was used to shed light into the nature of the activation rate constant...
June 7, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28577093/structure-of-rat-lungs-after-administration-of-magnetomicelles-based-on-the-carbon-coated-iron-nanoparticles
#16
G Yu Vasyukov, I V Sukhodolo, I V Mil'to, I V Mitrofanova
We studied the effects of single administration of a suspension of magnetomicelles based on carbon-coated iron nanoparticles on the structure of rat lungs within 40 days. Histological analysis revealed a complex of hemodynamic alterations in the lungs. Described changes persisted in the lung stroma from day 1 until day 40, but their intensity decreased by the end of the experiment. Using immunohistochemical Perls reaction we identified cells morphologically corresponding to alveolar and interstitial lung macrophages...
June 2, 2017: Bulletin of Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28471652/low-temperature-synthesis-of-heterostructures-of-transition-metal-dichalcogenide-alloys-wxmo1-xs2-and-graphene-with-superior-catalytic-performance-for-hydrogen-evolution
#17
Yu Lei, Srimanta Pakhira, Kazunori Fujisawa, Xuyang Wang, Oluwagbenga Oare Iyiola, Néstor Perea López, Ana Laura Elías, Lakshmy Pulickal Rajukumar, Chanjing Zhou, Bernd Kabius, Nasim Alem, Morinobu Endo, Ruitao Lv, Jose L Mendoza-Cortes, Mauricio Terrones
Large-area (∼cm(2)) films of vertical heterostructures formed by alternating graphene and transition-metal dichalcogenide (TMD) alloys are obtained by wet chemical routes followed by a thermal treatment at low temperature. In particular, we synthesized stacked graphene and WxMo1-xS2 alloy phases that were used as hydrogen evolution catalysts. We observed a Tafel slope of 38.7 mV dec(-1) and 96 mV onset potential (at current density of 10 mA cm(-2)) when the heterostructure alloy was annealed at 300 °C. These results indicate that heterostructures formed by graphene and W0...
May 12, 2017: ACS Nano
https://www.readbyqxmd.com/read/28418277/geographical-variation-in-the-skeletal-morphology-of-red-jungle-fowl
#18
H Endo, N Tsunekawa, M Sonoe, Tї Sasaki, H Ogawa, T Amano, T S Nguyen, V Phimphachanhvongsod, K Kudo, T Yonezawa, F Akishinonomiya
1. The skulls and postcranial skeletons of the red jungle fowl (Gallus gallus) were compared osteometrically between the populations from North and South Vietnam, North and Central Laos and Southeast Bangladesh. The populations include the three subspecies of G. g. spadiceus, G. g. gallus and G. g. murghi and were sampled to reveal the geographical morphological variations among populations in G. gallus. 2. The morphometric characteristics of subspecies murghi could be clearly distinguished from those of the other subspecies using a canonical discriminant analysis...
July 13, 2017: British Poultry Science
https://www.readbyqxmd.com/read/28389479/characterization-of-drosophila-saposin-related-mutants-as-a-model-for-lysosomal-sphingolipid-storage-diseases
#19
Julia Sellin, Heike Schulze, Marie Paradis, Dominic Gosejacob, Cyrus Papan, Andrej Shevchenko, Olympia Ekaterina Psathaki, Achim Paululat, Melanie Thielisch, Konrad Sandhoff, Michael Hoch
Sphingolipidoses are inherited diseases belonging to the class of lysosomal storage diseases (LSDs), which are characterized by the accumulation of indigestible material in the lysosome caused by specific defects in the lysosomal degradation machinery. While some LSDs can be efficiently treated by enzyme replacement therapy (ERT), this is not possible if the nervous system is affected due to the presence of the blood-brain barrier. Sphingolipidoses in particular often present as severe, untreatable forms of LSDs with massive sphingolipid and membrane accumulation in lysosomes, neurodegeneration and very short life expectancy...
June 1, 2017: Disease Models & Mechanisms
https://www.readbyqxmd.com/read/28363126/interaction-between-the-zebrafish-danio-rerio-organic-cation-transporter-1-oct1-and-endo-and-xenobiotics
#20
Ivan Mihaljević, Marta Popović, Roko Žaja, Nikola Maraković, Goran Šinko, Tvrtko Smital
Organic cation transporters (OCTs) serve as uptake transporters of numerous endo- and xenobiotics. They have been in the focus of medical toxicological research for more than a decade due to their key role in absorption, distribution, metabolism and excretion due to their expression on basolateral membranes of various barrier tissues. OCTs belong to the SLC22A family within the SLC (Solute carrier) protein superfamily, with three co-orthologs identified in humans (OCT1, 2 and 3), and two Oct orthologs in zebrafish (Oct1 and Oct2)...
June 2017: Aquatic Toxicology
keyword
keyword
3228
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"