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https://www.readbyqxmd.com/read/29676920/aliphatic-c-h-bond-oxidation-with-hydrogen-peroxide-catalyzed-by-manganese-complexes-directing-selectivity-through-torsional-effects
#1
Michela Milan, Massimo Bietti, Miquel Costas
Substituted N-cyclohexyl amides undergo aliphatic C-H bond oxidation with H2 O2 catalyzed by manganese complexes. The reactions are directed by torsional effects leading to site-selective oxidation of cis-1,4-, trans-1,3-, and cis-1,2-cyclohexanediamides. The corresponding diastereoisomers are unreactive under the same conditions. Competitive oxidation of cis- trans mixtures of 4-substituted N-cyclohexylamides leads to quantitative conversion of the cis-isomers, allowing isolation and successive conversion of the trans-isomers into densely functionalized oxidation products with excellent site selectivity and good enantioselectivity...
April 20, 2018: Organic Letters
https://www.readbyqxmd.com/read/29676416/self-plied-and-twist-stable-carbon-nanotube-yarn-artificial-muscles-driven-by-organic-solvent-adsorption
#2
Kaiyun Jin, Silan Zhang, Susheng Zhou, Jian Qiao, Yanhui Song, Jiangtao Di, Dengsong Zhang, Qingwen Li
Artificial yarn/fiber muscles have recently attracted considerable interest for various applications. These muscles can provide large-stroke tensile and torsional actuations, resulting from inserted twists. However, tensional tethering of twisted muscles is generally needed to avoid muscle snarling and untwisting. In this paper a carbon nanotube (CNT) yarn muscle that is tethering-free and twist-stable is reported. The yarn muscle is prepared by allowing the self-plying of a coiled CNT yarn. When driven by acetone adsorption, this muscle shows decoupled actuations, which provide fast and reversible ∼13...
April 20, 2018: Nanoscale
https://www.readbyqxmd.com/read/29675225/a-new-twist-in-the-photophysics-of-the-gfp-chromophore-a-volume-conserving-molecular-torsion-couple
#3
Jamie Conyard, Ismael A Heisler, Yohan Chan, Philip C Bulman Page, Stephen R Meech, Lluís Blancafort
The simple structure of the chromophore of the green fluorescent protein (GFP), a phenol and an imidazolone ring linked by a methyne bridge, supports an exceptionally diverse range of excited state phenomena. Here we describe experimentally and theoretically the photochemistry of a novel sterically crowded nonplanar derivative of the GFP chromophore. It undergoes an excited state isomerization reaction accompanied by an exceptionally fast (sub 100 fs) excited state decay. The decay dynamics are essentially independent of solvent polarity and viscosity...
February 21, 2018: Chemical Science
https://www.readbyqxmd.com/read/29675119/microscopic-features-of-fractured-fragment-of-nickel-titanium-endodontic-instruments-by-two-different-modes-of-torsional-loading
#4
Ibrahim H Abu-Tahun, Sang Won Kwak, Jung-Hong Ha, Hyeon-Cheol Kim
This study compared the microscopic features of the fractured endodontic nickel-titanium (NiTi) rotary instruments by two different torsional loadings: repetitive torsional loading (RTL) and single torsional loading (STL) based on the International Organization for Standardization (ISO). ProTaper Next, HyFlex EDM, and V-Taper 2 were compared in this study. In the STL method, the torsional load was applied after fixing the 3 mm tip of the file, by continuous clockwise rotation (2 rpm) until fracture. In the RTL method, a preset rotational loading (0...
2018: Scanning
https://www.readbyqxmd.com/read/29674673/proteomics-studies-on-the-three-larval-stages-of-development-and-metamorphosis-of-babylonia-areolata
#5
Minghui Shen, Guilan Di, Min Li, Jingqiang Fu, Qi Dai, Xiulian Miao, Miaoqin Huang, Weiwei You, Caihuan Ke
The ivory shell, Babylonia areolata, is a commercially important aquaculture species in the southeast coast of mainland China. The middle veliger stage, later veliger stage, and juvenile stage are distinct larval stages in B. areolata development. In this study, we used label-free quantification proteomics analysis of the three developmental stages of B. areolata. We identified a total of 5,583 proteins, of which 1,419 proteins expression level showed significant differential expression. The results of gene ontology enrichment analysis showed that the number of proteins involved in metabolic and cellular processes were the most abundant...
April 19, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29673677/torsion-of-pedunculated-subserous-uterine-leiomyoma-a-rare-complication-of-a-common-disease
#6
Yen-Ling Lai, Yu-Li Chen, Chi-An Chen, Wen-Fang Cheng
OBJECTIVE: To evaluate the clinical presentations, diagnosis, management, and outcomes of torsion of the pedunculated subserous uterine leiomyoma. MATERIALS AND METHODS: We retrospectively reviewed medical records of patients with subserous uterine leiomyomas undergoing surgeries at National Taiwan University Hospital from January 2001 to December 2015. RESULTS: Five cases of torsion of pedunculated subserous uterine leiomyoma were identified...
April 2018: Taiwanese Journal of Obstetrics & Gynecology
https://www.readbyqxmd.com/read/29671809/support-stiffness-monitoring-of-cylindrical-structures-using-magnetostrictive-transducers-and-the-torsional-mode-t-0-1
#7
Jabid Quiroga Mendez, Luis Mujica, Rodolfo Villamizar, Magda Ruiz
In this paper, a support stiffness monitoring scheme based on torsional guided waves for detecting loss of rigidity in a support of cylindrical structures is presented. Poor support performance in cylindrical specimens such as a pipeline setup located in a sloping terrain may produce a risky operation condition in terms of the installation integrity and the possibility of human casualties. The effects of changing the contact forces between support and the waveguide have been investigated by considering variations in the load between them...
April 19, 2018: Sensors
https://www.readbyqxmd.com/read/29671761/effects-of-the-tempering-and-high-pressure-torsion-temperatures-on-microstructure-of-ferritic-martensitic-steel-grade-91
#8
Artur Ganeev, Marina Nikitina, Vil Sitdikov, Rinat Islamgaliev, Andrew Hoffman, Haiming Wen
Grade 91 (9Cr-1Mo) steel was subjected to various heat treatments and then to high-pressure torsion (HPT) at different temperatures. Its microstructure was studied using transmission electron microscopy (TEM) and X-ray diffraction (XRD). Effects of the tempering temperature and the HPT temperature on the microstructural features and microhardness in the ultrafine-grained (UFG) Grade 91 steel were researched. The study of the UFG structure formation takes into account two different microstructures observed: before HPT in both samples containing martensite and in fully ferritic samples...
April 19, 2018: Materials
https://www.readbyqxmd.com/read/29670712/impact-of-different-rectangular-wires-on-torsional-expression-of-different-sizes-of-buccal-tube
#9
Shabnam Ajami, Afshar-Rasti Boroujeni
Background: Torsions in rectangular wires are the essential part of corrections in the finishing stage of treatment. Moreover the greatest amounts of torques are applied in the molar areas. a clinically effective moment is between 5 and 20 Nmm. In this study we have decided to evaluate the impact of different tube sizes and different dimensions of wires with different modulus of elasticities on the amount torsional bond strength of molar tubes. Material and Methods: 60 human impacted molar teeth were collected...
January 2018: Journal of Clinical and Experimental Dentistry
https://www.readbyqxmd.com/read/29670186/tension-induced-twist-of-twist-spun-carbon-nanotube-yarns-and-its-effect-on-their-torsional-behavior
#10
Seung-Yeol Jeon, Dongil Kwon, Woong-Ryeol Yu
Twist-spun carbon nanotube (CNT) yarns exhibit a large and reversible rotational behavior under specific boundary conditions. In situ polarized Raman spectroscopy revealed that a tension-induced twist provides reversibility to this rotation. The orientation changes of individual CNTs were followed when twist-spun CNT yarns were untwisted and subsequently retwisted. Twist-spun CNT yarn, when untwisted and subsequently retwisted under the one-ended tethered boundary condition, showed irreversible orientation changes of the individual CNTs due to snarls formed during the untwisting operation, which resulted in macroscopic irreversible rotational behavior of the CNT yarns...
April 18, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29669780/microinterventional-endocapsular-nucleus-disassembly-novel-technique-and-results-of-first-in-human-randomised-controlled-study
#11
Tsontcho Ianchulev, David F Chang, Edward Koo, Susan MacDonald, Ernesto Calvo, Farrell Toby Tyson, Andrea Vasquez, Iqbal Ike K Ahmed
AIM: To assess the safety and efficacy of microinterventional endocapsular nuclear fragmentation in moderate to severe cataracts. METHODS: This was a prospective single-masked multisurgeon interventional randomised controlled trial (ClinicalTrials.gov NCT02843594) where 101 eyes of 101 subjects with grade 3-4+ nuclear cataracts were randomised to torsional phacoemulsification alone (controls) or torsional phacoemulsification with adjunctive endocapsular nuclear fragmentation using a manual microinterventional nitinol filament loop device (miLOOP group)...
April 18, 2018: British Journal of Ophthalmology
https://www.readbyqxmd.com/read/29668277/hydrogen-atom-transfer-from-alkanols-and-alkanediols-to-the-cumyloxyl-radical-a-kinetic-evaluation-of-the-contribution-of-%C3%AE-c-h-activation-and-%C3%AE-c-h-deactivation
#12
Michela Salamone, Vanesa B Ortega, Teo Martin, Massimo Bietti
A kinetic study on the reactions of the cumyloxyl radical (CumO•) with a series of alkanols and alkanediols has been carried out. Predominant HAT from the α-C-H bonds of these substrates, activated by the presence of the OH group, is observed. The comparable kH values measured for ethanol and 1-propanol and the increase in kH measured on going from 1,2-diols to structurally related 1,3- and 1,4-diols is indicative of β-C-H deactivation toward HAT to the electrophilic CumO• determined by the electron withdrawing character of the OH group...
April 18, 2018: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29666745/torsion-of-the-omentum-a-rare-cause-of-acute-abdomen-in-a-14-year-old-boy
#13
Chijioke Chinaka, Shahbaz Mansoor, Mohamed Salaheidin
Acute abdominal pain is a common surgical presentation, and most often, the first line of consideration is to rule out acute appendicitis; this is more so when the patient is an adolescent or within younger age group. In most cases, other differentials are considered before omental torsion. Omental torsion is a cause of acute abdominal pain and sometimes mimics acute appendicitis in its presentation. We present a case of a 14-yr-old boy who presented with acute abdomen with symptoms mimicking acute appendicitis...
2018: Case Reports in Surgery
https://www.readbyqxmd.com/read/29666095/idiopathic-scrotal-fat-necrosis-an-unusual-cause-of-scrotal-pain
#14
Samuel John Davies, Ross Copping, Rajendra Kumar
The clinical differential diagnosis of scrotal pain with a mass in a prepubertal boy is difficult. Often conditions such as testicular torsion and epididymo-orchitis are diagnosed. We present a rare cause of scrotal pain, idiopathic scrotal fat necrosis. This condition has a typical clinical presentation and ultrasound findings that have been described in a limited number of case reports. However, if it is diagnosed correctly and confirmed with ultrasound, we hope that people will be treated without surgical intervention...
April 17, 2018: BMJ Case Reports
https://www.readbyqxmd.com/read/29665176/interplay-between-microwave-spectroscopy-and-x-ray-diffraction-the-molecular-structure-and-large-amplitude-motions-of-2-3-dimethylanisole
#15
Lynn Ferres, Khai-Nghi Truong, Wolfgang Stahl, Ha Vinh Lam Nguyen
To determine the structural properties of 2,3-dimethyl-anisole, a multidisciplinary approach was carried out where gas phase rotational spectroscopy recorded from 2 to 26.5 GHz using a pulsed molecular jet Fourier transform microwave spectrometer was combined with solid state X-ray diffraction. Both methods revealed that only one conformer with a heavy-atom planar structure exists. In the solid state, the packing in the monoclinic space group is P21/n with Z = 4. In the gas phase spectrum, torsional splittings due to the internal rotations of two methyl groups attached on the phenyl ring were resolved and analyzed, providing an estimate of the barriers to methyl internal rotation of V3 = 26...
April 17, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/29663146/thoraco-lumbar-fractures-with-blunt-traumatic-aortic-injury-in-adult-patients-correlations-and-management
#16
Giorgio Santoro, Alessandro Ramieri, Vito Chiarella, Massimo Vigliotta, Maurizio Domenicucci
PURPOSE: Traumatic thoraco-lumbar spine fracture spine with a concomitant blunt aortic injury is uncommon but potentially a fatal association. Our aim was to clarify: morphology of spinal fractures related to vascular damages and vice versa, diagnostic procedures and decision-making process for the best treatment options for spine and vessels. METHODS: We enrolled 42 cases culled from the literature and five personal ones, reviewing in detail by AO Spine Classification, Society of Vascular Surgery classification and Abbreviated Injury Scale for neurological evaluation...
April 16, 2018: European Spine Journal
https://www.readbyqxmd.com/read/29662993/conformationally-restricted-bicarbazoles-with-phenylene-bridges-displaying-deep-blue-emission-and-high-triplet-energies-systematic-structure-property-relationships
#17
Iain A Wright, Hameed A Al-Attar, Andrei S Batsanov, Andrew P Monkman, Martin R Bryce
The synthesis is reported of twelve new symmetrical carbazole dimers in which the carbazole units are linked via 1,4-phenylene spacers. There are two distinct series of compounds based on the position on the carbazole ring where the phenylene spacer is attached: this is either at carbazole C(3) (series 1a-1f) or at C(2) (series 2a-2f). The central phenylene ring is substituted with either two methyl, two methoxy or two cyano substituents which impart an intramolecular torsional angle between the phenylene and carbazole rings, thereby limiting the extent of π-conjugation between the carbazole units, and raising the triplet energies of the molecules to ET 2...
April 17, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29658434/bone-marrow-derived-cells-trafficking-to-the-oviduct-effect-of-ischemia-reperfusion-injury
#18
Cagdas Sahin, Ramanaiah Mamillapalli, Hugh S Taylor
The oviduct/fallopian tube is a crucial organ in the mammalian reproductive tract; it plays a critical role in gamete transportation and early embryo development. In women, torsion of the fallopian tubes can cause ischemia and reperfusion (IR) injury. In this study, we tested the effect of this injury on recruitment of bone marrow-derived cells (BMDCs) to the oviducts of reproductive age female mice. Bone marrow-derived cells were collected from ubiquitin-green fluorescent protein-positive male mice and transplanted into wild-type female mice...
January 1, 2018: Reproductive Sciences
https://www.readbyqxmd.com/read/29657687/multiple-bilateral-ovarian-mature-cystic-teratomas-with-ovarian-torsion-a-case-report
#19
Iman Fayez, Basel Khreisat, Tarek Athamneh, Reema Omoosh, Mayada A Daibes
Ovarian tumors are a common form of neoplasm in women. Mature cystic teratoma is the most common type, with a bilateral incidence of 8-15%. However, few cases are reported as bilateral and multiple. A rare case of bilateral multiple dermoid cysts in a 19-year-old female patient presented with abdominal pain of one-day duration. Her medical history was unremarkable. Ultrasonography showed multiple bilateral ovarian cystic masses. The patient underwent laparotomy. The masses were excised while preserving the remaining ovarian tissue...
March 2018: Oman Medical Journal
https://www.readbyqxmd.com/read/29653317/increased-torsional-stability-by-a-novel-femoral-neck-locking-plate-the-role-of-plate-design-and-pin-configuration-in-a-synthetic-bone-block-model
#20
Jan Egil Brattgjerd, Martin Loferer, Sanyalak Niratisairak, Harald Steen, Knut Strømsøe
BACKGROUND: In undisplaced femoral neck fractures, internal fixation remains the main treatment, with mechanical failure as a frequent complication. As torsional stable fixation promotes femoral neck fracture healing, the Hansson Pinloc® System with a plate interlocking pins, was developed from the original hook pins. Since its effect on torsional stability is undocumented, the novel implant was compared with the original configurations. METHODS: Forty-two proximal femur models custom made of two blocks of polyurethane foam were tested...
March 27, 2018: Clinical Biomechanics
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