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https://www.readbyqxmd.com/read/29346962/osmotic-mechanism-of-the-loop-extrusion-process
#1
Tetsuya Yamamoto, Helmut Schiessel
The loop extrusion theory assumes that protein factors, such as cohesin rings, act as molecular motors that extrude chromatin loops. However, recent single molecule experiments have shown that cohesin does not show motor activity. To predict the physical mechanism involved in loop extrusion, we here theoretically analyze the dynamics of cohesin rings on a loop, where a cohesin loader is in the middle and unloaders at the ends. Cohesin monomers bind to the loader rather frequently and cohesin dimers bind to this site only occasionally...
September 2017: Physical Review. E
https://www.readbyqxmd.com/read/29345925/catalytic-mechanism-of-the-ubiquitin-like-nedd8-transfer-in-ring-e3-e2-nedd8-target-complex-from-qm-mm-free-energy-simulations
#2
Yufei Yue, Yue Ma, Ping Qian, Hong Guo
Ubiquitin-like (UBL) protein modifications play a key role in regulating protein function. In contrast to the ubiquitin (UB) and small ubiquitin-like modifier (SUMO) which are ligated to a massive segment of proteome, the UBL NEDD8 is highly selective for modifying a lysine residue on closely related cullin proteins (CULs). In this study, the X-ray structure of a trapped E3-E2~NEDD8-target intermediate (RBX1-UBC1~NEDD8-CUL1-DCN1) is used to build computer models, and combined quantum mechanics/molecular mechanics (QM/MM) molecular dynamics (MD) and free energy (potential of mean force) simulations are performed to investigate the catalytic mechanism of the NEDD8 transfer from E2 to the lysine residue (K720) on the substrate in the complex...
January 18, 2018: Journal of Chemical Information and Modeling
https://www.readbyqxmd.com/read/29342326/mixed-fluorotryptophan-substitutions-at-the-same-residue-expand-the-versatility-of-%C3%A2-%C3%A2-f-protein-nmr-spectroscopy
#3
Calem Kenward, Kyungsoo Shin, Jan Rainey
The strategy of applying fluorine NMR to characterize ligand binding to a membrane protein prepared with mixtures of tryptophans substituted with F at different positions on the indole ring was tested. The ¹⁹F NMR behavior of 4-, 5-, 6-, and 7-fluorotryptophan were directly compared as a function of both micellar environment and fragment size for two overlapping apelin receptor (AR/APJ) segments - one with a single transmembrane (TM) helix and two tryptophan residues, the other with three TM helices and two additional tryptophan residues...
January 17, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29335104/vision-related-quality-of-life-and-dependency-in-french-keratoconus-patients-impact-study
#4
Valentine Saunier, Audrey-Elodie Mercier, Thibaut Gaboriau, Florence Malet, Joseph Colin, Pierre Fournié, François Malecaze, David Touboul
PURPOSE: To assess the quality of life in French keratoconus patients. SETTING: Fifty-seven Keratoconus National Reference Centers across France. DESIGN: Prospective case series. METHODS: Patients completed the National Eye Institute Visual Functioning Questionnaire-25 (NEI VFQ-25) and a French validated questionnaire on disability and dependency from February to June 2012 when they came for an ophthalmic examination at 57 participating centers across France...
December 2017: Journal of Cataract and Refractive Surgery
https://www.readbyqxmd.com/read/29312606/induction-of-renal-artery-hyperresponsiveness-by-alpha1-adrenoceptor-in-hepatorenal-syndrome
#5
Xiaogang Zhang, Xinsen Xu, Yina Jiang, Jianyu He, Wenjing Wang, Wei Li, Xufeng Zhang, Yi Lv
Objective: To investigate the potential role of alpha1-adrenoceptor (α1-AR) in the pathogenesis of hepatorenal syndrome. Methods: Hepatorenal syndrome was induced in male rats by intraperitoneal injection of D-galactosamine and orally treatment with α1-AR antagonist tamsulosin. Hyperresponsiveness of the renal artery contraction was evaluated by the laser-Doppler flowmetry and multimyograph system, while renal blood flow (cortical and medullary perfusion) was simultaneously measured...
December 12, 2017: Oncotarget
https://www.readbyqxmd.com/read/29287858/designing-a-tissue-engineered-tracheal-scaffold-for-preclinical-evaluation
#6
Cameron A Best, Victoria K Pepper, Devan Ohst, Kyle Bodnyk, Eric Heuer, Ekene A Onwuka, Nakesha King, Robert Strouse, Jonathan Grischkan, Christopher K Breuer, Jed Johnson, Tendy Chiang
OBJECTIVE: Recent efforts to tissue engineer long-segment tracheal grafts have been complicated by stenosis and malacia. It has been proposed that both the mechanical characteristics and cell seeding capacity of TETG scaffolds are integral to graft performance. Our aim was to design a tracheal construct that approximates the biomechanical properties of native sheep trachea and optimizes seeding with bone marrow derived mononuclear cells prior to preclinical evaluation in an ovine model...
January 2018: International Journal of Pediatric Otorhinolaryngology
https://www.readbyqxmd.com/read/29285740/grading-system-to-categorize-breast-mri-using-bi-rads-5th-edition-a-statistical-study-of-non-mass-enhancement-descriptors-in-terms-of-probability-of-malignancy
#7
Tatsunori Asada, Takayuki Yamada, Yoshihide Kanemaki, Keishi Fujiwara, Satoko Okamoto, Yasuo Nakajima
PURPOSE: To analyze the association of breast non-mass enhancement descriptors in the BI-RADS 5th edition with malignancy, and to establish a grading system and categorization of descriptors. MATERIALS AND METHODS: This study was approved by our institutional review board. A total of 213 patients were enrolled. Breast MRI was performed with a 1.5-T MRI scanner using a 16-channel breast radiofrequency coil. Two radiologists determined internal enhancement and distribution of non-mass enhancement by consensus...
December 29, 2017: Japanese Journal of Radiology
https://www.readbyqxmd.com/read/29284455/visual-rehabilitation-in-moderate-keratoconus-combined-corneal-wavefront-guided-transepithelial-photorefractive-keratectomy-and-high-fluence-accelerated-corneal-collagen-cross-linking-after-intracorneal-ring-segment-implantation
#8
Hun Lee, David Sung Yong Kang, Byoung Jin Ha, Jin Young Choi, Eung Kweon Kim, Kyoung Yul Seo, Tae-Im Kim
BACKGROUND: To investigate the effects of combined corneal wavefront-guided transepithelial photorefractive keratectomy (tPRK) and accelerated corneal collagen cross-linking (CXL) after intracorneal ring segment (ICRS) implantation in patients with moderate keratoconus. METHODS: Medical records of 23 eyes of 23 patients undergoing combined tPRK and CXL after ICRS implantation were retrospectively analyzed. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), corneal indices based on Scheimpflug tomography, higher-order aberrations (HOAs), and corneal biomechanical properties were evaluated before and after ICRS implantation, and at 1, 3, and 6 months after combined tPRK and CXL...
December 29, 2017: BMC Ophthalmology
https://www.readbyqxmd.com/read/29276328/a-fully-automated-multiscale-kernel-graph-cuts-based-particle-localization-scheme-for-temporal-focusing-two-photon-microscopy
#9
Xia Huang, Chunqiang Li, Chuan Xiao, Wenqing Sun, Wei Qian
The temporal focusing two-photon microscope (TFM) is developed to perform depth resolved wide field fluorescence imaging by capturing frames sequentially. However, due to strong nonignorable noises and diffraction rings surrounding particles, further researches are extremely formidable without a precise particle localization technique. In this paper, we developed a fully-automated scheme to locate particles positions with high noise tolerance. Our scheme includes the following procedures: noise reduction using a hybrid Kalman filter method, particle segmentation based on a multiscale kernel graph cuts global and local segmentation algorithm, and a kinematic estimation based particle tracking method...
March 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/29275457/clinical-outcomes-after-keraring-implantation-for-keratoconus-management-in-patients-older-than-40-years-a-retrospective-interventional-cohort-study
#10
Zisis Gatzioufas, Aye Khine, Mohamed Elalfy, Ivo Guber, Cameron McLintock, Francesco Sabatino, Samer Hamada, Damian Lake
BACKGROUND: Intracorneal ring segment implantation is an effective and safe method of visual improvement in patients with keratoconus. The aim of our study was to evaluate the long-term clinical outcomes after Keraring implantation for keratoconus in patients older than 40 years. METHODS: Eleven eyes from 11 patients with keratoconus who underwent femtosecond laser-assisted Keraring implantation for keratoconus were included in this retrospective study. The uncorrected visual acuity (UCVA), corrected visual acuity, keratometric readings, central corneal thickness and thinnest corneal pachymetry were evaluated preoperatively and 6 months after the Keraring implantation...
December 23, 2017: Ophthalmology and Therapy
https://www.readbyqxmd.com/read/29260121/late-extrusion-of-intrastromal-corneal-ring-segments-a-report-of-two-cases
#11
Julius T Oatts, Louis Savar, David G Hwang
Purpose: To report two cases of patients with late extrusion following uneventful implantation of intrastromal corneal ring segments (ICRS) for myopia. Observations: Two patients with previously implanted ICRS for low myopia presented with spontaneous onset of extrusion of their ICRS, one at 7 years post-operatively and the other at 17 and 20 years. Both cases underwent explantation and maintained excellent best-corrected visual acuity. These cases represent the longest reported intervals between implantation of the ICRS and subsequent extrusion...
December 2017: American Journal of Ophthalmology Case Reports
https://www.readbyqxmd.com/read/29249744/-a-successful-case-of-tracheal-segmental-resection-and-reconstruction-for-cicatricial-tracheal-stenosis
#12
Teruo Iwata, Yuusuke Nabe, Takeshi Hanagiri, Fumihiro Tanaka
A 45-year-old man had consciousness disorder due to fall trauma had received ventilation support and tracheostomy. Two months later, the tracheostomy tube was removed. One year later, he suffered from severe cicatricial tracheal stenosis. Under a diagnosis of post-intubation tracheal stenosis, he underwent circumferential resection and end-to-end anastomosis of the trachea. The central part of the resected trachea of 3 cartilage rings showed a stenosis like a pin hole. The post operative course was uneventful, and there was no stenosis or sutural insufficiency on examination by bronchoscopy...
2017: Journal of UOEH
https://www.readbyqxmd.com/read/29245369/-i-chironomus-i-i-alchichica-i-sp-n-diptera-chironomidae-from-lake-alchichica-mexico
#13
Raúl Acosta, Narcís Prat, Carles Ribera, Paraskeva Michailova, María Del Carmen Hernández-Fonseca, Javier Alcocer
Morphological analysis of all developmental stages (except female), mitochondrial DNA sequences from cytochrome c oxidase subunit I (cox1) and cytological analysis of the polytene chromosomes were used to describe a new species of Chironomus found in the littoral and profundal zones of an endorheic, warm-monomictic lake in Mexico. Male imago is distinguished by the shape of superior volsella and by an antennal and bristle ratio lower than two. The pupa is characterized by the spur morphology of abdominal segment VIII...
December 15, 2017: Zootaxa
https://www.readbyqxmd.com/read/29240120/1-7%C3%A2-%C3%A2-%C3%AE-m-band-narrow-linewidth-tunable-raman-fiber-lasers-pumped-by-spectrum-sliced-amplified-spontaneous-emission
#14
Peng Zhang, Di Wu, Quanli Du, Xiaoyan Li, Kexuan Han, Lizhong Zhang, Tianshu Wang, Huilin Jiang
A 1.7 μm band tunable narrow-linewidth Raman fiber laser based on spectrally sliced amplified spontaneous emission (SS-ASE) and multiple filter structures is proposed and experimentally demonstrated. In this scheme, an SS-ASE source is employed as a pump source in order to avoid stimulated Brillouin scattering. The ring configuration includes a 500 m long high nonlinear optical fiber and a 10 km long dispersion shifted fiber as the gain medium. A segment of un-pumped polarization-maintaining erbium-doped fiber is used to modify the shape of the spectrum...
December 10, 2017: Applied Optics
https://www.readbyqxmd.com/read/29239499/oligothienylenevinylene-polarons-and-bipolarons-confined-between-hostile-electron-accepting-perchlorotriphenylmethyl-radicals
#15
Juan Casado, Paula Mayorga Burrezo, Carlos Franco, Ruben Caballero, Marta Mas, Fernando Langa, Juan T Lopez Navarrete, Concepció Rovira, Jaume Veciana
: A detailed analysis of positive charged species generated on a series of thienylenevinylene (nTV) wires terminally substituted with two perchlorotriphenylmethyl (*PTM) radical acceptors groups, *PTM-nTV-PTM* (n = 2-7), has been carried out. Motivated by the counterintuitively key role played by holes in the nTV bridges on the operating mechanism of electron transfer in their radi-cal-anion mixed-valence derivatives, a wide combination of experimental and theoretical techniques have been used, aiming to get further insights on their structural location...
December 14, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29238735/post-keratoplasty-astigmatism-management-by-relaxing-incisions-a-systematic-review
#16
REVIEW
Gaëlle Ho Wang Yin, Louis Hoffart
Postoperative visual acuity can be limited by post-keratoplasty astigmatism, even with a clear corneal graft. Astigmatism management can be performed by selective suture removal, adjustment of sutures, optical correction, photorefractive procedures, wedge resection, intra-ocular lens implantation, intracorneal ring segments, relaxing incisions with or without compression sutures and repeated keratoplasty. Relaxing incisions can be made in the graft, graft-host interface or host cornea. Despite the unpredictability of the method because the flat and steep meridians are usually not orthogonal after penetrating keratoplasty, with asymmetric power distribution, all the studies showed an overall reduction of refractive, keratometric or topographic astigmatism, ranging from 30% to 72% with manual or femtosecond-assisted techniques...
2017: Eye and Vision (London, England)
https://www.readbyqxmd.com/read/29233836/radiomic-features-are-superior-to-conventional-quantitative-computed-tomographic-metrics-to-identify-coronary-plaques-with-napkin-ring-sign
#17
Márton Kolossváry, Júlia Karády, Bálint Szilveszter, Pieter Kitslaar, Udo Hoffmann, Béla Merkely, Pál Maurovich-Horvat
BACKGROUND: Napkin-ring sign (NRS) is an independent prognostic imaging marker of major adverse cardiac events. However, identification of NRS is challenging because of its qualitative nature. Radiomics is the process of extracting thousands of quantitative parameters from medical images to create big-data data sets that can identify distinct patterns in radiological images. Therefore, we sought to determine whether radiomic analysis improves the identification of NRS plaques. METHODS AND RESULTS: From 2674 patients referred to coronary computed tomographic angiography caused by stable chest pain, expert readers identified 30 patients with NRS plaques and matched these with 30 non-NRS plaques with similar degree of calcification, luminal obstruction, localization, and imaging parameters...
December 2017: Circulation. Cardiovascular Imaging
https://www.readbyqxmd.com/read/29233359/supra-annular-mitral-valve-replacement-in-an-infant-with-infective-endocarditis
#18
Sanae Yamauchi, Shigemitsu Iwai, Yuji Tominaga, Yosuke Kugo, Moyu Hasegawa, Futoshi Kayatani, Kunihiko Takahashi, Hisaaki Aoki, Hiroaki Kawata
We report the case of a female neonate born at 40 weeks' gestation with no known risk factors. On postnatal day 27, she was transferred to the pediatric intensive care unit and intubated for cardiorespiratory failure; she was diagnosed with group B streptococcus infective endocarditis. Mitral valve vegetations did not improve with antibiotic therapy. Mitral valve surgery was performed on postnatal day 36. A mechanical mitral valve with short-segment polytetrafluoroethylene skirt was inserted into the supra-annular position; gentian violet was applied to the sewing ring and skirt...
January 2018: Annals of Thoracic Surgery
https://www.readbyqxmd.com/read/29232506/thiolactone-chemistry-based-combinatorial-methodology-to-construct-multifunctional-polymers-for-efficacious-gene-delivery
#19
Zengshi Zha, Yongyi Hu, Jean Mukerabigwi, Weijian Chen, Yuheng Wang, Chuanxin He, Zhishen Ge
Hydrophobic segments and amino moieties in polymeric nonviral gene vectors play important roles in overcoming a cas-cade of barriers for efficient gene delivery. However, it remains a great challenge to facilely construct well-defined multi-functional polymers through optimization of the amino and hydrophobic groups. Herein, we choose thiolactone chemistry to perform the ring opening reaction of varying hydrophobic groups-modified thiolactones by various amines to generate mercapto groups for further Michael addition reaction with poly[2-(acryloyloxy)ethyl methacrylate] (PAOEMA)...
December 12, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/29226914/longitudinal-deformation-bench-testing-using-a-coronary-artery-model-a-new-standard
#20
COMMENT
Tawfiq R Choudhury, Salwan Al-Saigh, Steve Burley, Lin Li, Nizar Shakhshir, Nazanin Mirhosseini, Tao Wang, Samer Arnous, Muhammad A Khan, Mamas A Mamas, Douglas G W Fraser
Objectives: To compare susceptibility of five different stent platforms with longitudinal stent deformation (LSD) using a clinically relevant bench testing model simulating both short and long malapposed lengths. Background: Recent data suggest that design modifications to the Promus Element stent which led to the Promus Premier stent has reduced susceptibility to LSD. However, susceptibility to LSD at long malapposed lengths has not been tested. Furthermore, the mechanisms behind susceptibility to LSD are as yet unclear...
2017: Open Heart
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