Directing traffic on DNA-How transcription factors relieve or induce transcriptional interference.

Science.gov (United States)

Hao, Nan; Palmer, Adam C; Dodd, Ian B; Shearwin, Keith E

2017-03-15

Transcriptional interference (TI) is increasingly recognized as a widespread mechanism of gene control, particularly given the pervasive nature of transcription, both sense and antisense, across all kingdoms of life. Here, we discuss how transcription factor binding kinetics strongly influence the ability of a transcription factor to relieve or induce TI.

Newton-Cartan gravity and torsion

Science.gov (United States)

Bergshoeff, Eric; Chatzistavrakidis, Athanasios; Romano, Luca; Rosseel, Jan

2017-10-01

We compare the gauging of the Bargmann algebra, for the case of arbitrary torsion, with the result that one obtains from a null-reduction of General Relativity. Whereas the two procedures lead to the same result for Newton-Cartan geometry with arbitrary torsion, the null-reduction of the Einstein equations necessarily leads to Newton-Cartan gravity with zero torsion. We show, for three space-time dimensions, how Newton-Cartan gravity with arbitrary torsion can be obtained by starting from a Schrödinger field theory with dynamical exponent z = 2 for a complex compensating scalar and next coupling this field theory to a z = 2 Schrödinger geometry with arbitrary torsion. The latter theory can be obtained from either a gauging of the Schrödinger algebra, for arbitrary torsion, or from a null-reduction of conformal gravity.

Torque measurements reveal sequence-specific cooperative transitions in supercoiled DNA

Science.gov (United States)

Oberstrass, Florian C.; Fernandes, Louis E.; Bryant, Zev

2012-01-01

B-DNA becomes unstable under superhelical stress and is able to adopt a wide range of alternative conformations including strand-separated DNA and Z-DNA. Localized sequence-dependent structural transitions are important for the regulation of biological processes such as DNA replication and transcription. To directly probe the effect of sequence on structural transitions driven by torque, we have measured the torsional response of a panel of DNA sequences using single molecule assays that employ nanosphere rotational probes to achieve high torque resolution. The responses of Z-forming d(pGpC)n sequences match our predictions based on a theoretical treatment of cooperative transitions in helical polymers. “Bubble” templates containing 50–100 bp mismatch regions show cooperative structural transitions similar to B-DNA, although less torque is required to disrupt strand–strand interactions. Our mechanical measurements, including direct characterization of the torsional rigidity of strand-separated DNA, establish a framework for quantitative predictions of the complex torsional response of arbitrary sequences in their biological context. PMID:22474350

Intermittent Testicular Torsion

African Journals Online (AJOL)

2017-06-02

Jun 2, 2017 ... had prior episodes of testicular pain, suggesting that they may have had intermittent torsion before .... None of the patients had antecedent history of sexual exposure, fever, or urinary tract infection .... torsion of the spermatic cord portends an increased risk of acute testicular infarction. J Urol 2008;180 4 ...

Stability in quadratic torsion theories

Energy Technology Data Exchange (ETDEWEB)

Vasilev, Teodor Borislavov; Cembranos, Jose A.R.; Gigante Valcarcel, Jorge; Martin-Moruno, Prado [Universidad Complutense de Madrid, Departamento de Fisica Teorica I, Madrid (Spain)

2017-11-15

We revisit the definition and some of the characteristics of quadratic theories of gravity with torsion. We start from a Lagrangian density quadratic in the curvature and torsion tensors. By assuming that General Relativity should be recovered when the torsion vanishes and investigating the behaviour of the vector and pseudo-vector torsion fields in the weak-gravity regime, we present a set of necessary conditions for the stability of these theories. Moreover, we explicitly obtain the gravitational field equations using the Palatini variational principle with the metricity condition implemented via a Lagrange multiplier. (orig.)

Stability in quadratic torsion theories

International Nuclear Information System (INIS)

Vasilev, Teodor Borislavov; Cembranos, Jose A.R.; Gigante Valcarcel, Jorge; Martin-Moruno, Prado

2017-01-01

We revisit the definition and some of the characteristics of quadratic theories of gravity with torsion. We start from a Lagrangian density quadratic in the curvature and torsion tensors. By assuming that General Relativity should be recovered when the torsion vanishes and investigating the behaviour of the vector and pseudo-vector torsion fields in the weak-gravity regime, we present a set of necessary conditions for the stability of these theories. Moreover, we explicitly obtain the gravitational field equations using the Palatini variational principle with the metricity condition implemented via a Lagrange multiplier. (orig.)

Using torsion to manipulate spin currents

Science.gov (United States)

Fumeron, Sébastien; Berche, Bertrand; Medina, Ernesto; Santos, Fernando A. N.; Moraes, Fernando

2017-02-01

We address the problem of quantum particles moving on a manifold characterised by the presence of torsion along a preferential axis. In fact, such a torsion may be taylored by the presence of a single screw dislocation, whose Burgers vector measures the torsion amplitude. The problem, first treated in the relativistic limit describing fermions that couple minimally to torsion, is then analysed in the Pauli limit. We show that torsion induces a geometric potential and also that it couples generically to the phase of the wave function, giving rise to the possibility of using torsion to manipulate spin currents in the case of spinor wave functions. These results emerge as an alternative strategy for using screw dislocations in the design of spintronic-based devices.

Oophoropexy for Recurrent Ovarian Torsion

Directory of Open Access Journals (Sweden)

Jennifer Hartley

2018-01-01

Full Text Available A 31-year-old nulliparous patient presents with a three-day history of right sided colicky abdominal pain and associated nausea. This patient has previously presented twice with right sided ovarian torsion with the background of polycystic ovaries in the last two consecutive years. Blood tests were normal. Due to previous history, there was a high index of clinical suspicion that this may be a further torsion. Therefore, the patient was taken to theatre for a diagnostic laparoscopy and a further right sided ovarian torsion was noted. At this time, oophoropexy was performed to the uterosacral ligament to prevent further torsion in order to preserve the patients’ fertility. In this article, we detail this case and also provide a discussion of ovarian torsion including risk factors, presentation, and current thoughts on management.

Torsion in superstrings

International Nuclear Information System (INIS)

Bars, I.; Nemeschansky, D.; Yankielowicz, S.

1986-01-01

In this paper the authors discuss string theories on a background manifold with torsion. In the first part, candidate vacuum configurations for ten-dimensional superstrings are discussed. The authors compactify these on M/sub 4/xK, where M/sub 4/ is four-dimensional and K some compact six-dimensional manifold. In particular they are interested in investigating the existence of solutions with non-zero torsion on K. The compactification problem is approached both from the effective field theory point of view and directly using string considerations. The second part of the talk is devoted to the construction of string theories in curved space with torsion. The authors discuss both the Neveu-Schwarz-Ramond type string and the Green-Schwarz type string. Particular emphasis is put on the resulting constraints on space-time supersymmetry in the Green-Schwarz approach. This study uses two-dimensional non-linear sigma models to describe the propagation of strings in background geometries with torsion. The background field can be understood as arising from condensation of infinite number of strings

Isolated penile torsion in newborns.

Science.gov (United States)

Eroglu, Egemen; Gundogdu, Gokhan

2015-01-01

We reported on the incidence of isolated penile torsion among our healthy children and our approach to this anomaly. Between 2011 and 2014, newborn babies with penile torsion were classified according to the angle of torsion. Surgical correction (penile degloving and reattachment for moderate cases and dorsal dartos flap technique in case of resistance) after 6 months was advised to the babies with rotations more than 45°. Among 1000 newborn babies, 200 isolated penile torsions were found, and among these, 43 had torsions more than 45°, and 4 of these had angles greater than 90°. The mean angle of the rotations was found 30.45° (median: 20°). In total, 8 children with 60° torsions were previously circumcised. Surgery was performed on 19 patients, with a mean patient age of 12 ± 2 months. Of these 19, 13 babies were corrected with degloving and reattachment. This technique was not enough on the remaining 6 patients; therefore, derotational dorsal dartos flap was added to correct the torsion. After a mean of 15.6 ± 9.8 months, residual penile rotation, less than 15°, was found only in 2 children. The incidence of isolated penile torsion is 20% in newborns. However, rotation more than 45° angles are seen in 4.3% of male babies. Correction is not necessary in mild degrees, and penile degloving with reattachment is enough in most cases. If the initial correction is insufficient, dorsal dartos flap rotation is easy and effective. Prior circumcision neither disturbs the operative procedure nor affects the outcomes.

Development of a simple computerized torsion test to quantify subjective ocular torsion.

Science.gov (United States)

Kim, Y D; Yang, H K; Hwang, J-M

2017-11-01

PurposeThe double Maddox-rod test (DMRT) and Lancaster red-green test (LRGT) are the most widely used tests worldwide to assess subjective ocular torsion. However, these tests require equipment and the quantified results of ocular torsion are only provided in rough values. Here we developed a novel computerized torsion test (CTT) for individual assessment of subjective ocular torsion and validated the reliability and accuracy of the test compared with those of the DMRT and LRGT.MethodsA total of 30 patients with cyclovertical strabismus and 30 controls were recruited. The CTT was designed using Microsoft Office PowerPoint. Subjects wore red-green filter spectacles and viewed gradually tilted red and cyan lines on an LCD monitor and pressed the keyboard to go through the slides, until both lines seemed parallel. All subjects underwent the CTT, DMRT, and LRGT. Intraclass correlation coefficients and Bland-Altman plots were analyzed to assess the acceptability of the CTT compared with that of the DMRT.ResultsBoth the DMRT and CTT showed no significant test-retest differences in the strabismus and control groups. The DMRT and CTT results demonstrated an acceptable agreement. The reliability of the CTT was better than that of the DMRT. The LRGT showed low sensitivity for the detection of ocular torsion compared with the DMRT (40.0%) and CTT (39.1%).ConclusionOur results suggest that the assessment of subjective ocular torsion using the CTT based on PowerPoint software is simple, reproducible, and accurate and can be applied in clinical practice.

Torsional Tribological Behavior and Torsional Friction Model of Polytetrafluoroethylene against 1045 Steel

Science.gov (United States)

Wang, Shibo; Niu, Chengchao

2016-01-01

In this work, the plane-on-plane torsional fretting tribological behavior of polytetrafluoroethylene (PTFE) was studied. A model of a rigid, flat-ended punch acting on an elastic half-space was built according to the experimental conditions. The results indicate that the shape of T–θ curves was influenced by both the torsional angle and the normal load. The torsion friction torque and wear rate of PTFE exponentially decreased when the torsion angle rose. The torsional torque increased from 0.025 N·m under a normal load of 43 N to 0.082 N·m under a normal load of 123 N. With sequentially increasing normal load, the value of torque was maintained. With rising normal load, the wear mass loss of PTFE disks was increased and the wear rate was decreased. Good agreement was found with the calculated torque according to the model and the experimental torque except for that under a normal load of 163 N. The difference under a normal load of 163 N was caused by the coefficient of friction. Usually the coefficient of friction of a polymer decreases with increasing normal load, whereas a constant coefficient of friction was applied in the model. PMID:26799324

TORSION OF THE VERMIFORM APPENDIX: A CASE REPORT

Directory of Open Access Journals (Sweden)

Dr. Imtiaz Wani

2009-07-01

Full Text Available Torsion of the vermiform appendix is a rare condition with few cases reported in the literature. Various factors predispose to torsion. Various factors predispose to torsion. We report a case of primary torsion of the vermiform appendix. The clinical presentation was indistinguishable from acute appendicitis and the diagnosis was made at operation. Appendix was preileal in position and the direction of torsion was anticlockwise. There was intrinsic torsion with no obvious factor for torsion identified. Appendectomy was performed.

Torsion testing of bed joints

DEFF Research Database (Denmark)

Hansen, Klavs Feilberg; Pedersen, Carsten Mørk

2008-01-01

This paper describes a simple test method for determining the torsion strength of a single bed joint between two bricks and presents results from testing using this test method. The setup for the torsion test is well defined, require minimal preparation of the test specimen and the test can...... be carried out directly in a normal testing machine. The torsion strength is believed to be the most important parameter in out-of-plane resistance of masonry walls subjected to bending about an axis perpendicular to the bed joints. The paper also contains a few test results from bending of small walls about...... an axis perpendicular to the bed joints, which indicate the close connection between these results and results from torsion tests. These characteristics make the torsion strength well suited to act as substitute parameter for the bending strength of masonry about an axis perpendicular to the bed joints....

The odd side of torsion geometry

DEFF Research Database (Denmark)

Conti, Diego; Madsen, Thomas Bruun

2014-01-01

We introduce and study a notion of `Sasaki with torsion structure' (ST) as an odd-dimensional analogue of Kähler with torsion geometry (KT). These are normal almost contact metric manifolds that admit a unique compatible connection with 3-form torsion. Any odd-dimensional compact Lie group is sho...

El relieve de los Pirineos

OpenAIRE

Babault, Julien

2007-01-01

La evolución del relieve de los Pirineos es un buen ejemplo de la interacción entre procesos superficiales y profundos. La elevada topografía media de la cadena es fruto del acortamiento y engrosamiento cortical, hoy inactivo, que se produjo principalmente durante el Paleógeno. Aunque la topografía es antigua, el escarpado relieve local es moderno. La etapa paleógena culminó con la formación de superficies de erosión con bajo relieve, formadas ya desde su inicio a gran altitud, en relación co...

Induced quantum torsion

International Nuclear Information System (INIS)

Denardo, G.; Spallucci, E.

1985-07-01

We study pregeometry in the framework of a Poincare gauge field theory. The Riemann-Cartan space-time is shown to be an ''effective geometry'' for this model in the low energy limit. By using Heat Kernel techniques we find the induced action for curvature and torsion. We obtain in this way the usual Einstein-Hilbert action plus an axial Maxwell term describing the propagation of a massless, axial vector torsion field. (author)

The importance of topoisomerases for chromatin regulated genes

DEFF Research Database (Denmark)

Fredsøe, Jacob Christian; Pedersen, Jakob Madsen; Rødgaard, Morten Terpager

2013-01-01

DNA topoisomerases are enzymes, which function to relieve torsional stress in the DNA helix by introducing transient breaks into the DNA molecule. By use of Saccharomyces cerevisiae and microarray technology we have previously shown that topoisomerases are required for the activation of chromatin...... topoisomerases for optimal activation, but in contrast to the PHO5 gene, topoisomerases are not required for chromatin remodeling of the GAL1/10 promoter region, indicating a different role of the enzymes. We are currently performing a detailed investigation of the GAL genes to elucidate the precise role...

Torsional ultrasound mode versus combined torsional and conventional ultrasound mode phacoemulsification for eyes with hard cataract.

Science.gov (United States)

Fakhry, Mohamed A; El Shazly, Malak I

2011-01-01

To compare torsional versus combined torsional and conventional ultrasound modes in hard cataract surgery regarding ultrasound energy and time and effect on corneal endothelium. Kasr El Aini hospital, Cairo University, and International Eye Hospital, Cairo, Egypt. Ninety-eight eyes of 63 patients were enrolled in this prospective comparative randomized masked clinical study. All eyes had nuclear cataracts of grades III and IV using the Lens Opacities Classification System III (LOCS III). Two groups were included, each having an equal number of eyes (49). The treatment for group A was combined torsional and conventional US mode phacoemulsification, and for group B torsional US mode phacoemulsification only. Pre- and post-operative assessments included best corrected visual acuity (BCVA), intraocular pressure (IOP), slit-lamp evaluation, and fundoscopic evaluation. Endothelial cell density (ECD) and central corneal thickness (CCT) were measured preoperatively, 1 day, 7 days, and 1 month postoperatively. All eyes were operated on using the Alcon Infiniti System (Alcon, Fort Worth, TX) with the quick chop technique. All eyes were implanted with AcrySof SA60AT (Alcon) intraocular lens (IOL). The main phaco outcome parameters included the mean ultrasound time (UST), the mean cumulative dissipated energy (CDE), and the percent of average torsional amplitude in position 3 (%TUSiP3). Improvement in BCVA was statistically significant in both groups (P < 0.001). Comparing UST and CDE for both groups revealed results favoring the pure torsional group (P = 0.002 and P < 0.001 for UST; P = 0.058 and P = 0.009 for CDE). As for %TUSiP3, readings were higher for the pure torsional group (P = 0.03 and P = 0.01). All changes of CCT, and ECD over time were found statistically significant using one-way ANOVA testing (P < 0.001). Both modes are safe in hard cataract surgery, however the pure torsional mode showed less US energy used.

Tibiotalar torsion: bioengineering paradigm.

Science.gov (United States)

Michele, A A; Nielsen, P M

1976-10-01

1. Medial tibiotalar torsion is the most common disorder peculiar to mankind. 2. The pathogonomic findings are (a) an axial medially rotated and adducted distal third of the shaft of the tibia, (b) the plafond of the tibia with its mortise containing the "track-bound" talus, which is deflected strongly toward the tibial side, (c) an exaggerated midtarsal equinus, (d) ostensible restriction of dorsiflexion of the hindfoot against the tibia, (e) mild separation of the distal tibiofibular articulation, and (f) forward displacement of the gravitational axis to the naviculocunei-form joint. 3. Faulty leg crossing in utero resulting in an abnormal pelvofemoral-tibial design is discussed and its important consequences in the vulnerable 40 per cent of the population are emphasized. 4. The kinesiomechanics of the leg, ankle and foot is reviewed. 5. The radiographic parameters of medial tibiotalar torsion are presented, as well as the multiple facets of the clinical examination. 6. Methods of treatment depending on age and severity of the disorder are recommended. Surgery, detortional casts, and corrective footwear are discussed. Shoes presently available are inadequate for tibiotalar torsion and therefore engineering principles must be applied in the design and construction of all footwear, including sneakers and sportswear. This can be done only if the pathological biomechanics of this group of disorders is recognized. Biplane proximal tibial osteotomy is recommended in refractory cases, especially when tibiotalar torsion is demonstrated. 7. After 30 years of experience, the author finds that results with these patients have been uniformly good to excellent, depending on age and mode of treatment. 8. In medial tibiotalar torsion, the consequent adaptive changes are readily observed, but rarely are they recognized as the inevitable sequelae of medial tibiotalar torsion. 9. Adaptive compensating disorders are identified and their mechanism described. 10. The management of

Optically probing torsional superelasticity in spider silks

Energy Technology Data Exchange (ETDEWEB)

Kumar, Bhupesh; Thakur, Ashish; Panda, Biswajit; Singh, Kamal P. [Department of Physical Sciences, IISER Mohali, Sector 81, Manauli, Mohali 140306 (India)

2013-11-11

We investigate torsion mechanics of various spider silks using a sensitive optical technique. We find that spider silks are torsionally superelastic in that they can reversibly withstand great torsion strains of over 10{sup 2−3} rotations per cm before failure. Among various silks from a spider, we find the failure twist-strain is greatest in the sticky capture silk followed by dragline and egg-case silk. Our in situ laser-diffraction measurements reveal that torsional strains on the silks induce a nano-scale transverse compression in its diameter that is linear and reversible. These unique torsional properties of the silks could find applications in silk-based materials and devices.

Optically probing torsional superelasticity in spider silks

International Nuclear Information System (INIS)

Kumar, Bhupesh; Thakur, Ashish; Panda, Biswajit; Singh, Kamal P.

2013-01-01

We investigate torsion mechanics of various spider silks using a sensitive optical technique. We find that spider silks are torsionally superelastic in that they can reversibly withstand great torsion strains of over 10 2−3 rotations per cm before failure. Among various silks from a spider, we find the failure twist-strain is greatest in the sticky capture silk followed by dragline and egg-case silk. Our in situ laser-diffraction measurements reveal that torsional strains on the silks induce a nano-scale transverse compression in its diameter that is linear and reversible. These unique torsional properties of the silks could find applications in silk-based materials and devices

Dirac operators and Killing spinors with torsion

International Nuclear Information System (INIS)

Becker-Bender, Julia

2012-01-01

On a Riemannian spin manifold with parallel skew torsion, we use the twistor operator to obtain an eigenvalue estimate for the Dirac operator with torsion. We consider the equality case in dimensions four and six. In odd dimensions we describe Sasaki manifolds on which equality in the estimate is realized by Killing spinors with torsion. In dimension five we characterize all Killing spinors with torsion and obtain certain naturally reductive spaces as exceptional cases.

Interplay between DNA supercoiling and transcription elongation.

Science.gov (United States)

Ma, Jie; Wang, Michelle

2014-01-01

Transcription-coupled DNA supercoiling has been shown to be an important regulator of transcription that is broadly present in the cell. Here we review experimental work which shows that RNA polymerase is a powerful torsional motor that can alter DNA topology and structure, and DNA supercoiling in turn directly affects transcription elongation.

Torsional ultrasound mode versus combined torsional and conventional ultrasound mode phacoemulsification for eyes with hard cataract

Directory of Open Access Journals (Sweden)

Fakhry MA

2011-07-01

Full Text Available Mohamed A Fakhry1,2, Malak I El Shazly11Department of Ophthalmology, Kasr El Aini Hospital, Cairo University, Cairo, Egypt; 2Cataract and Refractive Consultant, International Eye Hospital, Cairo, EgyptPurpose: To compare torsional versus combined torsional and conventional ultrasound modes in hard cataract surgery regarding ultrasound energy and time and effect on corneal endothelium.Settings: Kasr El Aini hospital, Cairo University, and International Eye Hospital, Cairo, Egypt.Methodology: Ninety-eight eyes of 63 patients were enrolled in this prospective comparative randomized masked clinical study. All eyes had nuclear cataracts of grades III and IV using the Lens Opacities Classification System III (LOCS III. Two groups were included, each having an equal number of eyes (49. The treatment for group A was combined torsional and conventional US mode phacoemulsification, and for group B torsional US mode phacoemulsification only. Pre- and post-operative assessments included best corrected visual acuity (BCVA, intraocular pressure (IOP, slit-lamp evaluation, and fundoscopic evaluation. Endothelial cell density (ECD and central corneal thickness (CCT were measured preoperatively, 1 day, 7 days, and 1 month postoperatively. All eyes were operated on using the Alcon Infiniti System (Alcon, Fort Worth, TX with the quick chop technique. All eyes were implanted with AcrySof SA60AT (Alcon intraocular lens (IOL. The main phaco outcome parameters included the mean ultrasound time (UST, the mean cumulative dissipated energy (CDE, and the percent of average torsional amplitude in position 3 (%TUSiP3.Results: Improvement in BCVA was statistically significant in both groups (P < 0.001. Comparing UST and CDE for both groups revealed results favoring the pure torsional group (P = 0.002 and P < 0.001 for UST; P = 0.058 and P = 0.009 for CDE. As for %TUSiP3, readings were higher for the pure torsional group (P = 0.03 and P = 0.01. All changes of CCT, and ECD

Torsional structural response from free-field ground motion

International Nuclear Information System (INIS)

Lam, P.C.; Scavuzzo, R.J.

1979-01-01

Torsional response of structures subjected to the action of both the free-field torsional inputs and external torque is investigated. By expanding the work of Scanlan, both lateral and torsional foundation inputs due to a travelling shear wave are derived from the free-field point motion. These free-field torsional motions are used as the basis of numerical studies. Response for different soil stiffness and structural characteristics are studied, as well as different dynamic models. In one dynamic model the structure is coupled to the soil using a compliance spring matrix and in the second model the structure coupled to an elastic half-space. Results of these two basic models are compared and found to be in good agreement. Finally, torsional structural response caused by torsional inputs is compared with lateral response caused by modified lateral inputs to determine the significance of torsional excitation on the seismic response of building structures. Numerical results show that these torsional seismic loads are as large or larger than those from modified lateral inputs. (orig.)

Torsional Optomechanics of a Levitated Nonspherical Nanoparticle

Science.gov (United States)

Hoang, Thai M.; Ma, Yue; Ahn, Jonghoon; Bang, Jaehoon; Robicheaux, F.; Yin, Zhang-Qi; Li, Tongcang

2016-09-01

An optically levitated nanoparticle in vacuum is a paradigm optomechanical system for sensing and studying macroscopic quantum mechanics. While its center-of-mass motion has been investigated intensively, its torsional vibration has only been studied theoretically in limited cases. Here we report the first experimental observation of the torsional vibration of an optically levitated nonspherical nanoparticle in vacuum. We achieve this by utilizing the coupling between the spin angular momentum of photons and the torsional vibration of a nonspherical nanoparticle whose polarizability is a tensor. The torsional vibration frequency can be 1 order of magnitude higher than its center-of-mass motion frequency, which is promising for ground state cooling. We propose a simple yet novel scheme to achieve ground state cooling of its torsional vibration with a linearly polarized Gaussian cavity mode. A levitated nonspherical nanoparticle in vacuum will also be an ultrasensitive nanoscale torsion balance with a torque detection sensitivity on the order of 10-29 N m /√{Hz } under realistic conditions.

Pediatric ovarian torsion: an uncommon clinical entity

OpenAIRE

Rajwani, Kapil M; Mahomed, Anies

2014-01-01

Key Clinical Message Pediatric ovarian torsion is an infrequent diagnosis and it often mimics acute appendicitis. Most cases are due to underlying ovarian pathology and if left untreated, ovarian torsion may eventually cause peritonitis. Emergency exploratory laparoscopy represents a valuable diagnostic and therapeutic tool in suspected ovarian torsion.

Torsional heterotic geometries

International Nuclear Information System (INIS)

Becker, Katrin; Sethi, Savdeep

2009-01-01

We construct new examples of torsional heterotic backgrounds using duality with orientifold flux compactifications. We explain how duality provides a perturbative solution to the type I/heterotic string Bianchi identity. The choice of connection used in the Bianchi identity plays an important role in the construction. We propose the existence of a much larger landscape of compact torsional geometries using string duality. Finally, we present some quantum exact metrics that correspond to NS5-branes placed on an elliptic space. These metrics describe how torus isometries are broken by NS flux.

Torsional Rigidity of Minimal Submanifolds

DEFF Research Database (Denmark)

Markvorsen, Steen; Palmer, Vicente

2006-01-01

We prove explicit upper bounds for the torsional rigidity of extrinsic domains of minimal submanifolds $P^m$ in ambient Riemannian manifolds $N^n$ with a pole $p$. The upper bounds are given in terms of the torsional rigidities of corresponding Schwarz symmetrizations of the domains in warped...

Torsion (volvulus) of the lung

International Nuclear Information System (INIS)

Felson, B.

1986-01-01

Torsion or volvulus of the lung is a relatively rare but serious condition that can often be recognized or at least suspected radiographically. It occurs under three different sets of circumstances: spontaneously, usually in association with some other pulmonary abnormality; with traumatic pneumothorax; and as a complication of thoracic surgery. The author studied nine cases of torsion of the lung, including examples from each of these categories. The radiographic signs of torsion are as follows: a collapsed or consolidated lobe that occupies an unusual position, hilar displacement in a direction inappropriate for an apparently collapsed lobe, alteration of the normal position and sweep of the pulmonary vasculature, raid opacification of an ipsilateral lobe after trauma or lobectomy, marked change in position of an opacified lobe on sequential films, bronchial cutoff with no evidence of a mass, abnormal position of an affected lobe (shown on CT, angiography, or bronchography), and lobar air trapping. Mortality is high if the torsion goes unrecognized and operation is delayed

Association of Torsion With Testicular Cancer: A Retrospective Study.

Science.gov (United States)

Uguz, Sami; Yilmaz, Sercan; Guragac, Ali; Topuz, Bahadır; Aydur, Emin

2016-02-01

Testicular torsion is a medical emergency that usually requires surgical exploration. However, testicular malignancy has been anecdotally reported with the association of torsion in surgical specimens, and the published data remain scant on the association of torsion with testicular tumors. By retrospective medical record review, we identified 32 patients who had been diagnosed with testicular torsion, 20 of whom had undergone orchiectomy. Of these 20 patients, 2 were diagnosed with a malignancy. Our study, the largest case series to date, has shown an association between testicular torsion and testicular cancer of 6.4%. Testicular torsion is a medical emergency that usually requires surgical exploration. However, testicular malignancy has been anecdotally reported in association with torsion in surgical specimens. However, the published data remain scant on the association between torsion and the presence of testicular tumors. The present retrospective study explored the association between torsion and testicular cancer in patients with testicular torsion undergoing orchiectomy during scrotal exploration. A medical record review was performed of patients who had had a diagnosis of testicular torsion from January 2003 to February 2015. The clinicopathologic characteristics of the patients were recorded. A total of 32 patients were identified. Their mean age was 21.1 years (range, 7-39 years). All the patients had unilateral testicular torsion, which affected the left side in 17 and the right side in 15. Manual detorsion was successful in 6 patients, and 26 patients underwent emergency surgery with testicular detorsion (6 fixation surgery and 20 orchiectomy). The type of incision was scrotal in 6, inguinal in 10, and unspecified in 4. Pathologic examination of the orchiectomy specimens showed malignancy in 2 cases (seminoma and malign mixed germ cell tumor). To the best of our knowledge, the present single-center case series is the largest case series to date of

Experiments with a cryogenic torsion balance

International Nuclear Information System (INIS)

Newman, R.D.

1983-01-01

The torsion balance is a remarkably capable instrument for the measurement of slowly varying exceedingly small forces; indeed its potential abilities are still largely untapped. The author outlines some of the virtues (and limitations) of the torsion balance, and presents a menu of gravitation-related experiments to which it may be applied. He discusses plans for developing torsion balances operating at cryogenic temperatures, and describes an experiment to search for anomalous long-range interactions associated with intrinsic spin. (Auth.)

Torsional rigidity, isospectrality and quantum graphs

International Nuclear Information System (INIS)

Colladay, Don; McDonald, Patrick; Kaganovskiy, Leon

2017-01-01

We study torsional rigidity for graph and quantum graph analogs of well-known pairs of isospectral non-isometric planar domains. We prove that such isospectral pairs are distinguished by torsional rigidity. (paper)

Hematosalpinx torsion in an adolescent

Directory of Open Access Journals (Sweden)

Inês Vaz

2016-02-01

Full Text Available Introduction: Isolated fallopian tube torsion is an uncommon cause of acute lower abdominal pain. Ectopic pregnancy, hydro or hematosalpinx, endometriosis, adnexal masses and other causes of adnexal disease are predisposing factors. The diagnosis is difficult and often delayed due to the lack of pathognomonic symptoms, characteristic physical signs, and specific imaging and laboratory studies. Defi nitive diagnosis requires a surgical approach. Case report: The authors present a case of hematosalpinx and its tubal torsion in a virgin teenager with no prior predisposing factors. Discussion: This rare case may highlight a new insight into pathophysiology of tubal torsion and recalls hematosalpinx as a differential diagnosis.

Primary splenic torsion in a Boston terrier

International Nuclear Information System (INIS)

Ohta, H.; Takagi, S.; Murakami, M.; Sasaki, N.; Yoshikawa, M.; Nakamura, K.; Hwang, S.J.; Yamasaki, M.; Takiguchi, M.

2009-01-01

A 7-year-old female Boston terrier was referred to Hokkaido University Veterinary Teaching Hospital with a history of hemoglobinuria and anemia for several days. Abdominal radiographs showed splenomegaly, and ultrasonography revealed a hypoechoic splenic parenchyma with interspersed linear echoes consistent with the ultrasonographic appearance of splenic torsion. Ultrasonography and computed tomography (CT) indicated a C-shaped spleen. Exploratory laparotomy confirmed the diagnosis of splenic torsion. A splenectomy was performed, and the dog recovered well without complications. This is the first report of splenic torsion in Boston terriers, and the usefulness of ultrasonographic and CT findings of the splenic torsion was also confirmed

Primary splenic torsion in a Boston terrier.

Science.gov (United States)

OHTA, Hiroshi; TAKAGI, Satoshi; MURAKAMI, Masahiro; SASAKI, Noboru; YOSHIKAWA, Muneyoshi; NAKAMURA, Kensuke; HWANG, Shiang-Jyi; YAMASAKI, Masahiro; TAKIGUCHI, Mitsuyoshi

2009-11-01

A 7-year-old female Boston terrier was referred to Hokkaido University Veterinary Teaching Hospital with a history of hemoglobinuria and anemia for several days. Abdominal radiographs showed splenomegaly, and ultrasonography revealed a hypoechoic splenic parenchyma with interspersed linear echoes consistent with the ultrasonographic appearance of splenic torsion. Ultrasonography and computed tomography (CT) indicated a C-shaped spleen. Exploratory laparotomy confirmed the diagnosis of splenic torsion. A splenectomy was performed, and the dog recovered well without complications. This is the first report of splenic torsion in Boston terriers, and the usefulness of ultrasonographic and CT findings of the splenic torsion was also confirmed.

Isolated Penile Torsion in Brothers: A Case Report

Directory of Open Access Journals (Sweden)

Metin Gunduz

2012-04-01

Full Text Available Penile torsion can be congenital and associated with hypospadias and chordee, or can be acquired after circumcision. The incidence of isolated neonatal penile torsion was 1.7 to 27% in the literature. The majority were between 10 and deg; and 20 and deg;. Generally, torsion was to the left in cases. The techniques for correction of penile torsion described in the literature are penile de-gloving and reattaching of skin, resection of Buck's fascia incising the base of the penis and removing angular ellipses of corporeal tissue with subsequent plication of tunica, and dorsal dartos flap rotation in severe cases. In conclusion, penile torsion may be familial. Therefore, brothers should be examined carefully. The degloving and realignment technique is successful in isolated penile torsion. [Arch Clin Exp Surg 2012; 1(2.000: 122-124

Radiation stress relieving of polymer articles

International Nuclear Information System (INIS)

Frisch, D.C.; Weber, W.

1982-01-01

A method of rapidly relieving stress in an extruded or molded polymer article is disclosed. The method can be used in the preparation of printed circuit boards. An article comprised of the polymer is exposed to electromagnetic radiation, for a time period sufficient to absorb enough energy to stress relieve the polymer against stress cracking therein. Exposure occurs at one or more ranges of frequencies which are capable of being absorbed by the polymer and which are effective for stress relieving without or substantially without causing heat induced softening or flowing of the polymer. The electromagnetic radiation is selected from the ranges of infrared, microwave or ultraviolet radiation

Torsional carbon nanotube artificial muscles.

Science.gov (United States)

Foroughi, Javad; Spinks, Geoffrey M; Wallace, Gordon G; Oh, Jiyoung; Kozlov, Mikhail E; Fang, Shaoli; Mirfakhrai, Tissaphern; Madden, John D W; Shin, Min Kyoon; Kim, Seon Jeong; Baughman, Ray H

2011-10-28

Rotary motors of conventional design can be rather complex and are therefore difficult to miniaturize; previous carbon nanotube artificial muscles provide contraction and bending, but not rotation. We show that an electrolyte-filled twist-spun carbon nanotube yarn, much thinner than a human hair, functions as a torsional artificial muscle in a simple three-electrode electrochemical system, providing a reversible 15,000° rotation and 590 revolutions per minute. A hydrostatic actuation mechanism, as seen in muscular hydrostats in nature, explains the simultaneous occurrence of lengthwise contraction and torsional rotation during the yarn volume increase caused by electrochemical double-layer charge injection. The use of a torsional yarn muscle as a mixer for a fluidic chip is demonstrated.

Attentional Modulation of Eye Torsion Responses

Science.gov (United States)

Stevenson, Scott B.; Mahadevan, Madhumitha S.; Mulligan, Jeffrey B.

2016-01-01

Eye movements generally have both reflexive and voluntary aspects, but torsional eye movements are usually thought of as a reflexive response to image rotation around the line of sight (torsional OKN) or to head roll (torsional VOR). In this study we asked whether torsional responses could be modulated by attention in a case where two stimuli rotated independently, and whether attention would influence the latency of responses. The display consisted of rear-projected radial "pinwheel" gratings, with an inner annulus segment extending from the center to 22 degrees eccentricity, and an outer annulus segment extending from 22 degrees out to 45 degrees eccentricity. The two segments rotated around the center in independent random walks, stepping randomly 4 degrees clockwise or counterclockwise at 60 Hz. Subjects were asked to attend to one or the other while keeping fixation steady at the center of the display. To encourage attention on one or the other segment of the display, subjects were asked to move a joystick in synchrony with the back and forth rotations of one part of the image while ignoring the other. Eye torsion was recorded with the scleral search coil technique, sampled at 500 Hz. All four subjects showed roughly 50% stronger torsion responses to the attended compared to unattended segments. Latency varied from 100 to 150 msec across subjects and was unchanged by attention. These findings suggest that attention can influence eye movement responses that are not typically under voluntary control.

Inversion Therapy: Can It Relieve Back Pain?

Science.gov (United States)

Inversion therapy: Can it relieve back pain? Does inversion therapy relieve back pain? Is it safe? Answers from Edward R. Laskowski, M.D. Inversion therapy doesn't provide lasting relief from back ...

[Development of cough-relieving herbal teas].

Science.gov (United States)

Puodziūniene, Gene; Janulis, Valdimaras; Milasius, Arvydas; Budnikas, Vytautas

2005-01-01

Cough-relieving medicinal herbs in tea are used from ancient times. Mucilage present in them or secretion produced under the influence of the active substances covers the oral and throat mucosa soothing its irritability and relieving dry, tiresome cough. It is known that the mixtures of medicinal herbs (Specias) have a complex influence on the human organism and the rational combination of medicinal herbs can improve their curative action and decrease the undesirable side effects. Having summarized the properties of those medicinal herbs we decided to create two formulations of cough-relieving herbal tea. The first formulation consists of marshmallow roots, liquorice roots and lime flowers, the second -- of marshmallow roots, Iceland moss and lime flowers. The methods for identification and assay of the active substances in the compounds were applied. The purity of the mixtures was regulated by limitation of the loss on drying, total ash, microbial contamination, contamination with radionuclides, heavy metals, pesticides and foreign matter. The expiry date of both cough-relieving herbal teas was approved to be 2 years.

Secondary Torsion of Vermiform Appendix with Mucinous Cystadenoma

Directory of Open Access Journals (Sweden)

Maki Kitagawa

2007-06-01

Full Text Available Torsion of the vermiform appendix is a rare disorder, which causes abdominal symptoms indistinguishable from acute appendicitis. We report a case (a 34-year-old male of secondary torsion of the vermiform appendix with mucinous cystadenoma. This case was characterized by mild inflammatory responses, pentazocine-resistant abdominal pain, and appendiceal tumor, which was not enhanced by the contrast medium on computed tomography presumably because of reduced blood flow by the torsion. These findings may be helpful for the preoperative diagnosis of secondary appendiceal torsion.

Peculiar torsion dynamical response of spider dragline silk

Science.gov (United States)

Liu, Dabiao; Yu, Longteng; He, Yuming; Peng, Kai; Liu, Jie; Guan, Juan; Dunstan, D. J.

2017-07-01

The torsional properties of spider dragline silks from Nephila edulis and Nephila pilipes spiders are investigated by using a torsion pendulum technique. A permanent torsional deformation is observed after even small torsional strain. This behaviour is quite different from that of the other materials tested here, i.e., carbon fiber, thin metallic wires, Kevlar fiber, and human hair. The spider dragline thus displays a strong energy dissipation upon the initial excitation (around 75% for small strains and more for a larger strain), which correspondingly reduces the amplitude of subsequent oscillations around the new equilibrium position. The variation of torsional stiffness in relaxation dynamics of spider draglines for different excitations is also determined. The experimental result is interpreted in the light of the hierarchical structure of dragline silk.

Structural Modifications for Torsional Vibration Control of Shafting Systems Based on Torsional Receptances

Directory of Open Access Journals (Sweden)

Zihao Liu

2016-01-01

Full Text Available Torsional vibration of shafts is a very important problem in engineering, in particular in ship engines and aeroengines. Due to their high levels of integration and complexity, it is hard to get their accurate structural data or accurate modal data. This lack of data is unhelpful to vibration control in the form of structural modifications. Besides, many parts in shaft systems are not allowed to be modified such as rotary inertia of a pump or an engine, which is designed for achieving certain functions. This paper presents a strategy for torsional vibration control of shaft systems in the form of structural modifications based on receptances, which does not need analytical or modal models of the systems under investigation. It only needs the torsional receptances of the system, which can be obtained by testing simple auxiliary structure attached to relevant locations of the shaft system and using the finite element model (FEM of the simple structure. An optimization problem is constructed to determine the required structural modifications, based on the actual requirements of modal frequencies and mode shapes. A numerical experiment is set up and the influence of several system parameters is analysed. Several scenarios of constraints in practice are considered. The numerical simulation results demonstrate the effectiveness of this method and its feasibility in solving torsional vibration problems in practice.

Ultrasonographic features of prenatal testicular torsion: Case report

Directory of Open Access Journals (Sweden)

Elif Ağaçayak

2013-01-01

Full Text Available Although prenatal testicular torsion (PNTT is rarely observed,it is an important condition that can cause bilateralvanishing testis. Generally, PNTT cases observed asextravaginal torsion and treatment is emergency surgicalop-eration. In this article, 39 week presented a case diagnosedin the prenatal testicular torsion. PNTT diagnosiswas confirmed by Doppler ultrasonography and emergencysurgery was performed. Extravaginal left testiculartorsion gangrene and necrosis of the testis was observedin the operation. Left orchiectomy was performed andintrauter-ine ultrasonographic diagnosis was found to becorrect.Key words: Testicular torsion, prenatal diagnosis, features,ultrasonography

Torsion limits from t t macr production at the LHC

Science.gov (United States)

de Almeida, F. M. L.; de Andrade, F. R.; do Vale, M. A. B.; Nepomuceno, A. A.

2018-04-01

Torsion models constitute a well-known class of extended quantum gravity models. In this work, one investigates the phenomenological consequences of a torsion field interacting with top quarks at the LHC. A torsion field could appear as a new heavy state characterized by its mass and couplings to fermions. This new state would form a resonance decaying into a top antitop pair. The latest ATLAS t t ¯ production results from LHC 13 TeV data are used to set limits on torsion parameters. The integrated luminosity needed to observe torsion resonance at the next LHC upgrades are also evaluated, considering different values for the torsion mass and its couplings to Standard Model fermions. Finally, prospects for torsion exclusion at the future LHC phases II and III are obtained using fast detector simulations.

Torsion of the vermiform appendix: A case report | Wani | Internet ...

African Journals Online (AJOL)

Torsion of the vermiform appendix is a rare condition with few cases reported in the literature. Various factors predispose to torsion. Various factors predispose to torsion. We report a case of primary torsion of the vermiform appendix. The clinical presentation was indistinguishable from acute appendicitis and the diagnosis ...

Gallbladder torsion. Case report

DEFF Research Database (Denmark)

Brasso, K; Rasmussen, O V

1991-01-01

Gallbladder torsion is a rare surgical emergency occurring primarily in elderly women. The anatomical background is a variation in the attachment of the gallbladder to the inferior margin of the liver. Increasing life span will probably lead to an increasing number of cases, and gallbladder torsion...... must be kept in mind in patients with sudden onset of pain in the upper right quadrant, nausea, vomiting, and a palpable mass. None of the laboratory routines or non-invasive examinations enables one to make the right preoperative diagnosis. Treatment is cholecystectomy. Promptly treated, the prognosis...

How Do Pain Relievers Work? (For Kids)

Science.gov (United States)

... First Aid & Safety Doctors & Hospitals Videos Recipes for Kids Kids site Sitio para niños How the Body Works ... Español How Do Pain Relievers Work? KidsHealth / For Kids / How Do Pain Relievers Work? Print en español ¿ ...

Krukenberg Tumor: A Rare Cause of Ovarian Torsion

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Sameer Sandhu

2012-01-01

Full Text Available Ovarian torsion is the fifth most common gynecological surgical emergency. Ovarian torsion is usually associated with a cyst or a tumor, which is typically benign. The most common is mature cystic teratoma. We report the case of a 43-year-old woman who came to the Emergency Department with rare acute presentation of bilateral Krukenberg tumors, due to unilateral ovarian torsion. In this case report, we highlight the specific computed tomography (CT features of ovarian torsion and demonstrate the unique radiological findings on CT imaging. Metastasis to the ovary is not rare and 5 to 10% of all ovarian malignancies are metastatic. The stomach is the common primary site in most Krukenberg tumors (70%; an acute presentation of metastatic Krukenberg tumors with ovarian torsion is rare and not previously reported in radiology literature.

Hydroxyl free radical production during torsional phacoemulsification.

Science.gov (United States)

Aust, Steven D; Hebdon, Thomas; Humbert, Jordan; Dimalanta, Ramon

2010-12-01

To quantitate free radical generation during phacoemulsification using an ultrasonic phacoemulsification device that includes a torsional mode and evaluate tip designs specific to the torsional mode. Chemistry and Biochemistry Department, Utah State University, Logan, Utah, USA. Experimental study. Experiments were performed using the Infiniti Vision System and OZil handpiece. Hydroxyl radical concentrations in the aspirated irrigation solution during torsional phacoemulsification were quantitated as nanomolar malondialdehyde (nM MDA) and determined spectrophotometrically using the deoxyribose assay. The mean free radical production during phacoemulsification with torsional modality at 100% amplitude was 30.1 nM MDA ± 5.1 (SD) using a 0.9 mm 45-degree Kelman tapered ABS tip. With other tip designs intended for use with the torsional modality, free radical production was further reduced when fitted with the 0.9 mm 45-degree Kelman mini-flared ABS tip (13.2 ± 5.6 nM MDA) or the 0.9 mm 45-degree OZil-12 mini-flared ABS tip (14.3 ± 6.7 nM MDA). Although the measurements resulting from the use of the latter 2 tips were not statistically significantly different (P ≈ .25), they were different from those of the tapered tip (P<.0001). The MDA concentration in the aspirated irrigation solution using the torsional modality was approximately one half that reported for the handpiece's longitudinal modality in a previous study using the same bent-tip design (Kelman tapered, P<.0001). The level of MDA was further reduced approximately one half with torsional-specific tips. Copyright © 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Heat production: Longitudinal versus torsional phacoemulsification.

Science.gov (United States)

Han, Young Keun; Miller, Kevin M

2009-10-01

To compare the heat production of longitudinal versus torsional phacoemulsification under strict laboratory test conditions. Department of Ophthalmology, David Geffen School of Medicine at UCLA, and Jules Stein Eye Institute, Los Angeles, California, USA. Two Infiniti phacoemulsification handpieces were inserted into silicone test chambers filled with a balanced salt solution and imaged serially using a thermal camera. Incision compression was simulated by suspending 25.3 g weights from the silicone chambers. To simulate occlusion of the phacoemulsification tip, the aspiration line was clamped. Peak temperatures were measured 0, 10, 30, 60, and 120 seconds after the commencement of continuous ultrasound power. The 2 handpieces, operating exclusively in longitudinal or torsional modes, were compared 3 ways: (1) using the same power displayed on the instrument console, (2) using identical stroke lengths, and (3) using the same applied energy, a product of stroke length and frequency. For all 3 comparisons, torsional phacoemulsification resulted in lower temperatures at each time point. At the same displayed power setting, the scenario most familiar to cataract surgeons, longitudinal phacoemulsification elevated temperatures up to 41.5 degrees C more than torsional phacoemulsification. Torsional phacoemulsification generated less heat than longitudinal phacoemulsification in all 3 comparison tests. Lower operating temperatures indicate lower heat generation within the same volume of fluid, and this may provide additional thermal protection during cataract surgery.

Comparison of torsional and longitudinal modes using phacoemulsification parameters.

Science.gov (United States)

Rekas, Marek; Montés-Micó, Robert; Krix-Jachym, Karolina; Kluś, Adam; Stankiewicz, Andrzej; Ferrer-Blasco, Teresa

2009-10-01

To compare phacoemulsification parameters of torsional and longitudinal ultrasound modes. Ophthalmology Department, Military Health Service Institute, Warsaw, Poland. This prospective study evaluated eyes 1, 7, and 30 days after phacoemulsification with an Infiniti Vision System using the torsional or longitudinal ultrasound (US) mode. Cataract classification was according to the Lens Opacities Classification System II. Nucleus fragmentation was by the phaco-chop and quick-chop methods. Primary outcome measures were phaco time, mean phaco power, mean torsional amplitude, and aspiration time. Total energy, defined as cumulative dissipated energy (CDE) x aspiration time, and the effective coefficient, defined as aspiration time/phaco time, were also calculated. Four hundred eyes were evaluated. The CDE was statistically significantly lower in the torsional mode for nucleus grades I, II, and III (P.05). Aspiration time was statistically significantly shorter in the torsional mode than in the longitudinal mode for nucleus grades III and IV (P<.05). Total energy was significantly lower in the torsional mode for all nucleus densities (P<.05). The effective coefficient was significantly lower in the longitudinal mode except for nucleus grade I (P<.05). Torsional phacoemulsification was more effective than longitudinal phacoemulsification in the amount of applied fluid and the quantity of US energy expended. With the torsional method, it was possible to maintain a constant ratio of amount of fluid flow to quantity of US energy used, regardless of nucleus density.

Annealing helicase HARP closes RPA-stabilized DNA bubbles non-processively

NARCIS (Netherlands)

Burnham, D.R.; Nijholt, B.; de Vlaminck, I.; Quan, Jinhua; Yusufzai, Timur; Dekker, C.

2017-01-01

We investigate the mechanistic nature of the Snf2 family protein HARP, mutations of which are responsible for Schimke immuno-osseous dysplasia. Using a single-molecule magnetic tweezers assay, we construct RPA-stabilized DNA bubbles within torsionally constrained DNA to investigate the annealing

Ultimate Strength of Ship Hulls under Torsion

DEFF Research Database (Denmark)

Paik, Jeom Kee; Thayamballi, Anil K.; Pedersen, Preben Terndrup

2001-01-01

For a ship hull with large deck openings such as container vessels and some large bulk carriers, the analysis of warping stresses and hatch opening deformations is an essential part of ship structural analyses. It is thus of importance to better understand the ultimate torsional strength characte......For a ship hull with large deck openings such as container vessels and some large bulk carriers, the analysis of warping stresses and hatch opening deformations is an essential part of ship structural analyses. It is thus of importance to better understand the ultimate torsional strength...... characteristics of ships with large hatch openings. The primary aim of the present study is to investigate the ultimate strength characteristics of ship hulls with large hatch openings under torsion. Axial (warping) as well as shear stresses are normally developed for thin-walled beams with open cross sections...... subjected to torsion. A procedure for calculating these stresses is briefly described. As an illustrative example, the distribution and magnitude of warping and shear stresses for a typical container vessel hull cross section under unit torsion is calculated by the procedure. By theoretical and numerical...

Fast Torsional Artificial Muscles from NiTi Twisted Yarns.

Science.gov (United States)

Mirvakili, Seyed M; Hunter, Ian W

2017-05-17

Torsional artificial muscles made of multiwalled carbon nanotube/niobium nanowire yarns have shown remarkable torsional speed and gravimetric torque. The muscle structure consists of a twisted yarn with half of its length infiltrated with a stimuli-responsive guest material such as paraffin wax. The volumetric expansion of the guest material creates the torsional actuation in the yarn. In the present work, we show that this type of actuation is not unique to wax-infiltrated carbon multiwalled nanotube (MWCNT) or niobium nanowire yarns and that twisted yarn of NiTi alloy fibers also produces fast torsional actuation. By gold-plating half the length of a NiTi twisted yarn and Joule heating it, we achieved a fully reversible torsional actuation of up to 16°/mm with peak torsional speed of 10 500 rpm and gravimetric torque of 8 N·m/kg. These results favorably compare to those of MWCNTs and niobium nanowire yarns.

Wet-Spun Biofiber for Torsional Artificial Muscles.

Science.gov (United States)

Mirabedini, Azadeh; Aziz, Shazed; Spinks, Geoffrey M; Foroughi, Javad

2017-12-01

The demands for new types of artificial muscles continue to grow and novel approaches are being enabled by the advent of new materials and novel fabrication strategies. Self-powered actuators have attracted significant attention due to their ability to be driven by elements in the ambient environment such as moisture. In this study, we demonstrate the use of twisted and coiled wet-spun hygroscopic chitosan fibers to achieve a novel torsional artificial muscle. The coiled fibers exhibited significant torsional actuation where the free end of the coiled fiber rotated up to 1155 degrees per mm of coil length when hydrated. This value is 96%, 362%, and 2210% higher than twisted graphene fiber, carbon nanotube torsional actuators, and coiled nylon muscles, respectively. A model based on a single helix was used to evaluate the torsional actuation behavior of these coiled chitosan fibers.

Appendicular Torsion

African Journals Online (AJOL)

A‑2/103, Shivranjan Towers, Someshwarwadi, Pashan, Pune ‑ 411 008,. Maharashtra, India. E‑mail: spdubhashi@gmail.com. INTRODUCTION. Acute appendicitis presents with pain in right iliac fossa. Torsion of the vermiform appendix, though rare, also presents in a similar fashion, and it is detectable only at operation.[1].

Measurement of tibial torsion by computer tomography

Energy Technology Data Exchange (ETDEWEB)

Jend, H.H.; Heller, M.; Dallek, M.; Schoettle, H. (Hamburg Univ. (Germany, F.R.))

1981-01-01

A CT procedure for objective measurements of tibial torsion independent of axial rotation in the nearby joints is described. Transverse sections in defined planes of the tibia permit easy calculation of normal and abnormal congenital or posttraumatic angles of torsion. In 69 limbs normal tibial torsion was 40/sup 0/+-9/sup 0/. In a series of 42 limbs with complicated healing of a fracture of both bones of the leg it is shown that tibial maltorsion is a deformity which in most cases leads to arthrosis of the ankle joint.

Torsion of wandering spleen and distal pancreas

International Nuclear Information System (INIS)

Sheflin, J.R.; Lee, C.M.; Kretchmar, K.A.

1984-01-01

Wandering spleen is the term applied to the condition in which a long pedicle allows the spleen to lie in an abnormal location. Torsion of a wandering spleen is an unusual cause of an acute abdomen and is rarely diagnosed preoperatively. Associated torsion of the distal pancreas is even more uncommon. The authors describe a patient with torsion of a wandering spleen and distal pancreas, who was correctly diagnosed, and define the merits of the imaging methods used. The initial examination should be 99 /sup m/Tc-sulfur colloid liner-spleen scanning

Measurement of tibial torsion by computer tomography

International Nuclear Information System (INIS)

Jend, H.-H.; Heller, M.; Dallek, M.; Schoettle, H.

1981-01-01

A CT procedure for objective measurements of tibial torsion independent of axial rotation in the nearby joints is described. Transverse sections in defined planes of the tibia permit easy calculation of normal and abnormal congenital or posttraumatic angles of torsion. In 69 limbs normal tibial torsion was 40 0 +-9 0 . In a series of 42 limbs with complicated healing of a fracture of both bones of the leg it is shown that tibial maltorsion is a deformity which in most cases leads to arthrosis of the ankle joint. (Auth.)

Torsional malalignment, how much significant in the trochanteric fractures?

Science.gov (United States)

Kim, Tae Young; Lee, Yong Beom; Chang, Jun Dong; Lee, Sang Soo; Yoo, Jae Hyun; Chung, Kook Jin; Hwang, Ji Hyo

2015-11-01

The rotational alignment is definitely important in the long bones such as tibias and femurs. We also predict the importance of rotational alignment in the trochanteric fractures. So we measured torsional malalignment in trochanteric fracture and anlaysed their risk factors and their clinical significance. A total of 109 inpatients who had undergone internal fixation following trochanteric fracture and a postoperative pelvic CT scan between 2008 and 2013, with at least one year follow-up, were selected. Factors that affect torsional malalignment, such as age, gender, fracture stability, injured area, operative time, time of surgery after admission, and ASA status, were investigated. Factors that affect the patients' clinical results in malrotation, including ambulation time after surgery, postoperative complication rates, pain assessment of VAS one year postoperatively and Koval score, were also investigated. Of the 109 subjects, torsional malalignment was observed in 28 (25.7%) subjects with a mean torsional malalignment angle of 20.7° (range: -31.2° to 27.1°). Torsional malalignment risk factors were fracture stability (p=0.021) and operative time (p=0.043). In terms of the time to ambulation after surgery, the postoperative complication rates, and the VAS and Koval scores at one year postoperatively, no statistically significant difference was observed between the torsional malalignment patients and the non-deformity patients. In this study, 25.7% of the patients who had undergone internal fixation following trochanteric fracture experienced torsional malalignment. Major factors of the torsional malalignment were an unstable fracture and the consequent delay in the operative time. But the torsional malalignment was deemed to have no effect on clinical results. Copyright © 2015 Elsevier Ltd. All rights reserved.

Simultaneous acute appendicitis with right testicular torsion

Directory of Open Access Journals (Sweden)

Tanveer Akhtar

2012-01-01

Full Text Available We present a child with both acute appendicitis and torsion of the right testis presenting at the same time. Testicular torsion possibly occurring due to vomiting in acute appendicitis so far has not been reported in the literature.

Some torsion potentials

Energy Technology Data Exchange (ETDEWEB)

Grundberg, J; Lindstrom, U

1986-10-01

Using the notion of torsion potentials, the duality between antisymmetric tensor fields and scalar fields is discussed. First-order actions with these fields, the connection and the metric as independent variables are presented.

A new hybrid longitudinal–torsional magnetostrictive ultrasonic transducer

International Nuclear Information System (INIS)

Karafi, Mohammad Reza; Hojjat, Yousef; Sassani, Farrokh

2013-01-01

In this paper, a novel hybrid longitudinal–torsional magnetostrictive ultrasonic transducer (HL–TMUT) is introduced. The transducer is composed of a magnetostrictive exponential horn and a stainless steel tail mass. In this transducer a spiral magnetic field made up of longitudinal and circumferential magnetic fields is applied to the magnetostrictive horn. As a result, the magnetostrictive horn oscillates simultaneously both longitudinally and torsionally in accordance with the Joule and Wiedemann effects. The magnetostrictive exponential horn is designed in such a manner that it has the same longitudinal and torsional resonant frequency. It is made up of ‘2V Permendur’, which has isotropic magnetic properties. The differential equations of the torsional and longitudinal vibration of the horn are derived, and a HL–TMUT is designed with a resonant frequency of 20 573 Hz. The natural frequency and mode shapes of the transducer are considered theoretically and numerically. The experimental results show that this transducer resonates torsionally and longitudinally with frequencies of 20 610 Hz and 20 830 Hz respectively. The maximum torsional displacement is 1.5 mrad m −1 and the maximum longitudinal displacement is 0.6 μm. These are promising features for industrial applications. (paper)

Appendicular Torsion | Dubhashi | Nigerian Journal of Surgery

African Journals Online (AJOL)

. It can be primary or secondary. This is a case report of 52-year-old female with 180° anti-clockwise rotation of the appendix. Torsion can further leads to strangulation and infarction of the organ. Appendicular torsion could be included in the ...

Torsional Vibration of a Shafting System under Electrical Disturbances

Directory of Open Access Journals (Sweden)

Ling Xiang

2012-01-01

Full Text Available Torsional vibration responses of a nonlinear shafting system are studied by a modified Riccati torsional transfer matrix combining with the Newmark-β method. Firstly, the system is modeled as a chain consisting of an elastic spring with concentrated mass points, from which a multi-segment lumped mass model is established. Secondly, accumulated errors are eliminated from the eigenfrequencies and responses of the system's torsional vibration by this newly developed procedure. The incremental transfer matrix method, combining the modified Riccati torsional transfer matrix with Newmark-β method, is further applied to solve the dynamical equations for the torsional vibration of the nonlinear shafting system. Lastly, the shafting system of a turbine-generator is employed as an illustrating example, and simulation analysis has been performed on the transient responses of the shaft's torsional vibrations during typical power network disturbances, such as three-phase short circuit, two-phase short circuit and asynchronous juxtaposition. The results validate the present method and are instructive for the design of a turbo-generator shaft.

Pseudotopological quasilocal energy of torsion gravity

Science.gov (United States)

Ko, Sheng-Lan; Lin, Feng-Li; Ning, Bo

2017-08-01

Torsion gravity is a natural extension to Einstein gravity in the presence of fermion matter sources. In this paper we adopt Wald's covariant method of calculating the Noether charge to construct the quasilocal energy of the Einstein-Cartan-fermion system, and find that its explicit expression is formally independent of the coupling constant between the torsion and axial current. This seemingly topological nature is unexpected and is reminiscent of the quantum Hall effect and topological insulators. However, a coupling dependence does arise when evaluating it on shell, and thus the situation is pseudotopological. Based on the expression for the quasilocal energy, we evaluate it for a particular solution on the entanglement wedge and find agreement with the holographic relative entropy obtained before. This shows the equivalence of these two quantities in the Einstein-Cartan-fermion system. Moreover, the quasilocal energy in this case is not always positive definite, and thus it provides an example of a swampland in torsion gravity. Based on the covariant Noether charge, we also derive the nonzero fermion effect on the Komar angular momentum. The implications of our results for future tests of torsion gravity in gravitational-wave astronomy are also discussed.

Right paratesticular abscess mimicking neonatal testicular torsion ...

African Journals Online (AJOL)

U.O. Ezomike

Abstract. The clinical presentation of neonatal paratesticular abscess may closely resemble that of, neonatal testicular torsion and the use of scrotal ultrasonography to differentiate the two has low, sensitivity. We propose early operative treatment of suspected neonatal testicular torsion to salvage, the testicle in cases of ...

Torsion sensing based on patterned piezoelectric beams

Science.gov (United States)

Cha, Youngsu; You, Hangil

2018-03-01

In this study, we investigated the sensing characteristics of piezoelectric beams under torsional loads. We used partially patterned piezoelectric beams to sense torsion. In particular, the piezoelectric patches are located symmetrically with respect to the line of the shear center of the beam. The patterned piezoelectric beam is modeled as a slender beam, and its electrical responses are obtained by piezoelectric electromechanical equations. To validate the modeling framework, experiments are performed using a setup that forces pure torsional deformation. Three different geometric configurations of the patterned piezoelectric layer are used for the experiments. The frequency and amplitude of the forced torsional load are systematically varied in order to study the behavior of the piezoelectric sensor. Experimental results demonstrate that two voltage outputs of the piezoelectric beam are approximately out of phase with identical amplitude. Moreover, the length of the piezoelectric layers has a significant influence on the sensing properties. Our theoretical predictions using the model support the experimental findings.

Adnexal torsion in 6 years old girl

International Nuclear Information System (INIS)

Plachkov, I.; Tzvetankov, K.; Dimova, M.; Dobreva, Tz.; Hadjidekov, G.

2012-01-01

MRI and US findings in Ovarian torsion in a premenarcheal girl are described. Adnexal torsion is an uncommon cause of severe lower abdominal pain in young women (mean age is 10-11), and in 50% of cases such symptoms are observed in pre-menarchal females. However, adnexal torsion should be considered in all premenarcheal girls admitted with acute abdominal pain and evidence of an ovarian mass. Accurate imaging is crucial after onset of early clinical symptoms to confirm the diagnosis and to preserve the viability of the affected ovary. A pelvic ovoid mass was visualised on ultrasound, suggesting several hypothesis -cystic mass, ovarian torsion, dermoid. Magnetic resonance imaging visualized edematous ovary enlargement and the presence of multiple follicules at the periphery due to congestion from the twisted vascular pedicule. Smooth wail thickening of the partially necrotic. Twisted ovary was seen in the subacute phase, which has been confirmed during laparoscopy. CT was not considered in this 6 years old girl due to ionizing radiation. (authors)

Torsion and geometrostasis in covariant superstrings

Energy Technology Data Exchange (ETDEWEB)

Zachos, C.

1985-01-01

The covariant action for freely propagating heterotic superstrings consists of a metric and a torsion term with a special relative strength. It is shown that the strength for which torsion flattens the underlying 10-dimensional superspace geometry is precisely that which yields free oscillators on the light cone. This is in complete analogy with the geometrostasis of two-dimensional sigma-models with Wess-Zumino interactions. 13 refs.

Torsion and geometrostasis in covariant superstrings

International Nuclear Information System (INIS)

Zachos, C.

1985-01-01

The covariant action for freely propagating heterotic superstrings consists of a metric and a torsion term with a special relative strength. It is shown that the strength for which torsion flattens the underlying 10-dimensional superspace geometry is precisely that which yields free oscillators on the light cone. This is in complete analogy with the geometrostasis of two-dimensional sigma-models with Wess-Zumino interactions. 13 refs

Torsional regulation of hRPA-induced unwinding of double-stranded DNA

NARCIS (Netherlands)

De Vlaminck, I.; Vidic, I.; Van Loenhout, M.T.J.; Kanaar, R.; Lebbink, J.H.G.; Dekker, C.

2010-01-01

All cellular single-stranded (ss) DNA is rapidly bound and stabilized by single stranded DNA-binding proteins (SSBs). Replication protein A, the main eukaryotic SSB, is able to unwind double-stranded (ds) DNA by binding and stabilizing transiently forming bubbles of ssDNA. Here, we study the

Thermal stress relieving of dilute uranium alloys

International Nuclear Information System (INIS)

Eckelmeyer, K.H.

1981-01-01

The kinetics of thermal stress relieving of uranium - 2.3 wt % niobium, uranium - 2.0 wt % molybdenum, and uranium - 0.75 wt % titanium are reported and discussed. Two temperature regimes of stress relieving are observed. In the low temperature regime (T 0 C) the process appears to be controlled by an athermal microplasticity mechanism which can be completely suppressed by prior age hardening. In the high temperature regime (300 0 C 0 C) the process appears to be controlled by a classical diffusional creep mechanism which is strongly dependent on temperature and time. Stress relieving is accelerated in cases where it occurs simultaneously with age hardening. The potential danger of residual stress induced stress corrosion cracking of uranium alloys is discussed

experimental and analytical comparison of torsion, bending moment

African Journals Online (AJOL)

HOD

In structural analysis and design, the effects of torsion are usually neglected ... bending and torsion, using these codes and experimental work; and validates the ..... [7] Kharagpur, I. Structural Analysis: Civil Engineering. Course Material (Vol.

Muscular Basis of Whisker Torsion in Mice and Rats.

Science.gov (United States)

Haidarliu, Sebastian; Bagdasarian, Knarik; Shinde, Namrata; Ahissar, Ehud

2017-09-01

Whisking mammals move their whiskers in the rostrocaudal and dorsoventral directions with simultaneous rolling about their long axes (torsion). Whereas muscular control of the first two types of whisker movement was already established, the anatomic muscular substrate of the whisker torsion remains unclear. Specifically, it was not clear whether torsion is induced by asymmetrical operation of known muscles or by other largely unknown muscles. Here, we report that mystacial pads of newborn and adult rats and mice contain oblique intrinsic muscles (OMs) that connect diagonally adjacent vibrissa follicles. Each of the OMs is supplied by a cluster of motor end plates. In rows A and B, OMs connect the ventral part of the rostral follicle with the dorsal part of the caudal follicle. In rows C-E, in contrast, OMs connect the dorsal part of the rostral follicle to the ventral part of the caudal follicle. This inverse architecture is consistent with previous behavioral observations [Knutsen et al.: Neuron 59 (2008) 35-42]. In newborn mice, torsion occurred in irregular single twitches. In adult anesthetized rats, microelectrode mediated electrical stimulation of an individual OM that is coupled with two adjacent whiskers was sufficient to induce a unidirectional torsion of both whiskers. Torsional movement was associated with protracting movement, indicating that in the vibrissal system, like in the ocular system, torsional movement is mechanically coupled to horizontal and vertical movements. This study shows that torsional whisker rotation is mediated by specific OMs whose morphology and attachment sites determine rotation direction and mechanical coupling, and motor innervation determines rotation dynamics. Anat Rec, 300:1643-1653, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Teenage testicular torsion. | Onuigbo | International Journal of ...

African Journals Online (AJOL)

Aim: To study testicular torsion in teenagers in the Igbo community. Method: A retrospective study was carried out as regards requests for pathological examination of specimens received at a Regional Reference Laboratory based in Enugu. Results: Over a period of 30 years, 28 surgical specimens of testicular torsion in ...

C(α) torsion angles as a flexible criterion to extract secrets from a molecular dynamics simulation.

Science.gov (United States)

Victor Paul Raj, Fredrick Robin Devadoss; Exner, Thomas E

2014-04-01

Given the increasing complexity of simulated molecular systems, and the fact that simulation times have now reached milliseconds to seconds, immense amounts of data (in the gigabyte to terabyte range) are produced in current molecular dynamics simulations. Manual analysis of these data is a very time-consuming task, and important events that lead from one intermediate structure to another can become occluded in the noise resulting from random thermal fluctuations. To overcome these problems and facilitate a semi-automated data analysis, we introduce in this work a measure based on C(α) torsion angles: torsion angles formed by four consecutive C(α) atoms. This measure describes changes in the backbones of large systems on a residual length scale (i.e., a small number of residues at a time). Cluster analysis of individual C(α) torsion angles and its fuzzification led to continuous time patches representing (meta)stable conformations and to the identification of events acting as transitions between these conformations. The importance of a change in torsion angle to structural integrity is assessed by comparing this change to the average fluctuations in the same torsion angle over the complete simulation. Using this novel measure in combination with other measures such as the root mean square deviation (RMSD) and time series of distance measures, we performed an in-depth analysis of a simulation of the open form of DNA polymerase I. The times at which major conformational changes occur and the most important parts of the molecule and their interrelations were pinpointed in this analysis. The simultaneous determination of the time points and localizations of major events is a significant advantage of the new bottom-up approach presented here, as compared to many other (top-down) approaches in which only the similarity of the complete structure is analyzed.

Dynamics of continuous medium in space with torsion

International Nuclear Information System (INIS)

Krechet, V.G.

1985-01-01

In frames of Einstein-Cartan gravitation theory general properties of continuous media dynamics using description formalism of continuous medium steam-line congruence geometry are investigated. Raichaudhuri type equations in space with torsion applied to study the problem of singularities in gravitation theory are derived. It is shown that space-time torsion tensor trace may immediately affect volumetric autoparallel divergence and torsion pseudo trace - rotation of continuous medium steam-line congruences. Using formalism considered metrics of homogeneous rotation nonstationary cosmological model is determined and investigated

Unusual cause of acute abdominal pain in a postmenopausal woman: adnexal torsion

Directory of Open Access Journals (Sweden)

Alper Biler

2016-03-01

Full Text Available Adnexal torsion is an infrequent but significant cause of acute lower abdominal pain in women. While adnexal torsion is generally considered in premenopausal women presenting with acute abdominal pain and a pelvic mass, it is a rare cause of acute abdominal pain during postmenopausal period. The diagnosis of adnexal torsion is often challenging due to nonspesific clinical, laboratory and physical examination findings. Causes of adnexal torsion is also different in premenopausal and postmenopausal women. While a simple functional cyst is often the cause of torsion in premenopausal women, it is more rarely the cause in postmenopausal women. Adnexal torsion is a surgical emergency. The surgery of adnexal torsion is performed either via conventional exploratory laparotomy or laparoscopic surgery. Adnexal torsion in postmenopausal women should be considered not only in the setting of sudden onset pain, but also in long-term abdominal discomfort. In this article, we presented a case with adnexal torsion that rarely cause acute abdominal pain in postmenopausal women. [Cukurova Med J 2016; 41(1.000: 167-170

Torsion induces gravity

International Nuclear Information System (INIS)

Aros, Rodrigo; Contreras, Mauricio

2006-01-01

In this work the Poincare-Chern-Simons and anti-de Sitter-Chern-Simons gravities are studied. For both, a solution that can be cast as a black hole with manifest torsion is found. Those solutions resemble Schwarzschild and Schwarzschild-AdS solutions, respectively

Direct torsional actuation of microcantilevers using magnetic excitation

Energy Technology Data Exchange (ETDEWEB)

Gosvami, Nitya Nand; Nalam, Prathima C.; Tam, Qizhan; Carpick, Robert W., E-mail: carpick@seas.upenn.edu [Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Exarhos, Annemarie L.; Kikkawa, James M. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

2014-09-01

Torsional mode dynamic force microscopy can be used for a wide range of studies including mapping lateral contact stiffness, torsional frequency or amplitude modulation imaging, and dynamic friction measurements of various materials. Piezo-actuation of the cantilever is commonly used, but it introduces spurious resonances, limiting the frequency range that can be sampled, and rendering the technique particularly difficult to apply in liquid medium where the cantilever oscillations are significantly damped. Here, we demonstrate a method that enables direct torsional actuation of cantilevers with high uniformity over wide frequency ranges by attaching a micrometer-scale magnetic bead on the back side of the cantilever. We show that when beads are magnetized along the width of the cantilever, efficient torsional actuation of the cantilevers can be achieved using a magnetic field produced from a solenoid placed underneath the sample. We demonstrate the capability of this technique by imaging atomic steps on graphite surfaces in tapping mode near the first torsional resonance of the cantilever in dodecane. The technique is also applied to map the variations in the lateral contact stiffness on the surface of graphite and polydiacetylene monolayers.

Torsional Newton–Cartan geometry from Galilean gauge theory

International Nuclear Information System (INIS)

Banerjee, Rabin; Mukherjee, Pradip

2016-01-01

Using the recently advanced Galilean gauge theory (GGT) we give a comprehensive construction of torsional Newton–Cartan (NC) geometry. The coupling of a Galilean symmetric model with background NC geometry following GGT is illustrated by a free nonrelativistic scalar field theory. The issue of spatial diffeomorphism (Son and Wingate 2006 Ann. Phys. 321 197–224; Banerjee et al 2015 Phys. Rev. D 91 084021) is focussed from a new angle. The expression of the torsionful connection is worked out, which is in complete parallel with the relativistic theory. Also, smooth transition of the connection to its well known torsionless expression is demonstrated. A complete (implicit) expression of the torsion tensor for the NC spacetime is provided where the first-order variables occur in a suggestive way. The well known result for the temporal part of torsion is reproduced from our expression. (paper)

Mechanical origins of rightward torsion in early chick brain development

Science.gov (United States)

Chen, Zi; Guo, Qiaohang; Dai, Eric; Taber, Larry

2015-03-01

During early development, the neural tube of the chick embryo undergoes a combination of progressive ventral bending and rightward torsion. This torsional deformation is one of the major organ-level left-right asymmetry events in development. Previous studies suggested that bending is mainly due to differential growth, however, the mechanism for torsion remains poorly understood. Since the heart almost always loops rightwards that the brain twists, researchers have speculated that heart looping affects the direction of brain torsion. However, direct evidence is lacking, nor is the mechanical origin of such torsion understood. In our study, experimental perturbations show that the bending and torsional deformations in the brain are coupled and that the vitelline membrane applies an external load necessary for torsion to occur. Moreover, the asymmetry of the looping heart gives rise to the chirality of the twisted brain. A computational model and a 3D printed physical model are employed to help interpret these findings. Our work clarifies the mechanical origins of brain torsion and the associated left-right asymmetry, and further reveals that the asymmetric development in one organ can induce the asymmetry of another developing organ through mechanics, reminiscent of D'Arcy Thompson's view of biological form as ``diagram of forces''. Z.C. is supported by the Society in Science - Branco Weiss fellowship, administered by ETH Zurich. L.A.T acknowledges the support from NIH Grants R01 GM075200 and R01 NS070918.

f(R) gravity, torsion and non-metricity

International Nuclear Information System (INIS)

Sotiriou, Thomas P

2009-01-01

For both f(R) theories of gravity with an independent symmetric connection (no torsion), usually referred to as Palatini f(R) gravity theories, and for f(R) theories of gravity with torsion but no non-metricity, called U4 theories, it has been shown that the independent connection can actually be eliminated algebraically, as long as this connection does not couple to matter. Remarkably, the outcome in both cases is the same theory, which is dynamically equivalent with an ω 0 = -3/2 Brans-Dicke theory. It is shown here that even for the most general case of an independent connection with both non-metricity and torsion, one arrives at exactly the same theory as in the more restricted cases. This generalizes the previous results and explains why assuming that either the torsion or the non-metricity vanishing ultimately leads to the same theory. It also demonstrates that f(R) actions cannot support an independent connection which carries dynamical degrees of freedom, irrespective of how general this connection is, at least as long as there is no connection-matter coupling. (fast track communication)

Resolution of torsional vibration issue for large turbine generators

International Nuclear Information System (INIS)

Evans, D.G.; Giesecke, H.D.; Willman, E.C.; Moffitt, S.P.

1995-01-01

The excitation of turbine generator torsional natural frequencies in the region near 120 Hz by electrical transients in the power system has resulted in blade failures for several large 1,800 rpm nuclear turbines. At Cleveland Electric's Perry Nuclear Power plant a combination of advanced measurement techniques and analyses were used to identify and resolve a potential torsional vibration problem without adverse impact on the plant availability. The Perry turbine generator consists of a high pressure turbine, three low pressure turbines with 43 inch last stage blades, and a 1,250 MWe four pole generator operating at 1,800 rpm. Torsional vibration measurements obtained from random vibration during operation were acquired just prior to the 1994 refueling outage. The measurements indicated that the 26th torsional mode of vibration was just under 120 Hz and within the range of frequencies for which the manufacturer recommends modifying the unit to shift the problem torsional natural frequency. Extensive analytical modeling was used to design a modification to shift the torsional natural frequencies away from 120 Hertz and the modification was implemented during the refueling outage without affecting outage critical path. An off-line ramp test and additional on-line monitoring performed at the conclusion of the outage confirmed that the on-line method provided accurate measurements of the torsional natural frequencies and demonstrated that, with the modification, the torsional natural frequencies were sufficiently removed from 120 Hertz to allow turbine generator operation. The modification, which involved brazing of the tie wires on all last stage blades, also significantly reduces the stress on the last stage blades that result from negative sequence currents, further increasing the operating margin of the turbine generator with respect to electrical transients and faults

Experimental investigation of torsional vibration isolation using Magneto Rheological Elastomer

Directory of Open Access Journals (Sweden)

Praveen Shenoy K

2018-01-01

Full Text Available Rotating systems suffer from lateral and torsional vibrations which have detrimental effect on the roto-dynamic performance. Many available technologies such as vibration isolators and vibration absorbers deal with the torsional vibrations to a certain extent, however passive isolators and absorbers find less application when the input conditions are dynamic. The present work discusses use of a smart material called as Magneto Rheological Elastomer (MRE, whose properties can be changed based on magnetic field input, as a potential isolator for torsional vibrations under dynamic loading conditions. Carbonyl Iron Particles (CIP of average size 5 μm were mixed with RTV Silicone rubber to form the MRE. The effect of magnetic field on the system parameters was comprehended under impulse loading conditions using a custom built in-house system. Series arrangement of accelerometers were used to differentiate between the torsional and the bending modes of vibration of the system. Impact hammer tests were carried out on the torsional system to study its response, in the presence and absence of magnetic field. The tests revealed a shift in torsional frequency in the presence of magnetic field which elucidates the ability of MRE to work as a potential vibration isolator for torsional systems.

Online Identification and Verification of the Elastic Coupling Torsional Stiffness

Directory of Open Access Journals (Sweden)

Wanyou Li

2016-01-01

Full Text Available To analyze the torsional vibration of a diesel engine shaft, the torsional stiffness of the flexible coupling is a key kinetic parameter. Since the material properties of the elastic element of the coupling might change after a long-time operation due to the severe working environment or improper use and the variation of such properties will change dynamic feature of the coupling, it will cause a relative large calculation error of torsional vibration to the shaft system. Moreover, the torsional stiffness of the elastic coupling is difficult to be determined, and it is inappropriate to measure this parameter by disassembling the power unit while it is under normal operation. To solve these problems, this paper comes up with a method which combines the torsional vibration test with the calculation of the diesel shafting and uses the inherent characteristics of shaft torsional vibration to identify the dynamic stiffness of the elastic coupling without disassembling the unit. Analysis results show that it is reasonable and feasible to identify the elastic coupling dynamic torsional stiffness with this method and the identified stiffness is accurate. Besides, this method provides a convenient and practical approach to examine the dynamic behavior of the long running elastic coupling.

Determination of the Glass-Transition Temperature of GRPS and CFRPS Using a Torsion Pendulum in Regimes of Freely Damped Vibrations and Quasi-Stastic Torsion of Specimens

Science.gov (United States)

Startsev, V. O.; Lebedev, M. P.; Molokov, M. V.

2018-03-01

A method to measure the glass-transition temperature of polymers and polymeric matrices of composite materials with the help of an inverse torsion pendulum over a wide range of temperatures is considered combining the method of free torsional vibrations and a quasi-static torsion of specimens. The glass-transition temperature Tg of a KMKS-1-80. T10 fiberglass, on increasing the frequency of freely damped torsional vibrations from 0.7 to 9.6 Hz, was found to increase from 132 to 140°C. The value of Tg of these specimens, determined by measuring the work of their torsion through a small fixed angle was 128.6°C ± 0.8°C. It is shown that the use of a torsion pendulum allows one to determine the glass-transition temperature of polymeric or polymer matrices of PCMs in dynamic and quasi-static deformation regimes of specimens.

Torsional osteotomies of the tibia in patellofemoral dysbalance.

Science.gov (United States)

Dickschas, Jörg; Tassika, Aliki; Lutter, Christoph; Harrer, Jörg; Strecker, Wolf

2017-02-01

Anterior knee pain or patellofemoral instability is common symptom of patellofemoral dysbalance or maltracking. Tibial torsional deformities can be the reason of this pathology. After appropriate diagnostic investigation, the treatment of choice is a torsional osteotomy. This study addresses the diagnostic investigation, treatment, and the outcome of torsional osteotomies of the tibia. Does this treatment result in patellofemoral stability and provide pain relief? Forty-nine tibial torsional osteotomies were included. The major symptoms were patellofemoral instability in 19 cases and anterior knee pain in 42 cases. In addition to clinical and radiographic analysis, a torsional angle CT scan was performed pre-operatively. A visual analog scale (VAS), the Japanese Knee Society score, the Tegner activity score, and the Lysholm score were assessed pre-operatively and at the 42-month follow-up. Mean tibial external torsion was 47.4° (SD 5.41; range 37°-66°; standard value 34°). Surgical treatment consisted of an acute supratuberositary tibial internal torsional osteotomy (mean 10.8°; SD 3.01°; range 5°-18°). At the follow-up investigation, the Tegner activity score was increased 0.4 points (p value 0.014) from 3.9 (SD 1.33; range 2-7) to 4.3 (SD 1.25; range 0-7). The Lysholm score increased 26 points (SD 16.32; p value 0.001) from 66 (SD 14.94; range 32-94) to 92 (SD 9.29; range 70-100) and the Japanese Knee Society score increased 18 points (SD 14.70; p value 0.001) from 72 (SD 13.72, range 49-100) to 90 (SD 9.85, range 60-100). VAS was reduced 3.4 points (SD 2.89; p value 0.001) from 5.7 (SD 2.78; range 0-10) to 2.3 (SD 1.83; range 0-7). As regards patellofemoral instability, no redislocation occurred in the follow-up period. The results of this study show that in cases of tibial maltorsion, a torsional osteotomy can lead to patellofemoral stability and pain relief, and should be considered as a treatment option. The improved clinical scores in the present

Painless inter epididymal testicular torsion of the spermatic cord

OpenAIRE

Salomon V. Romano; Haime S. Hernan; Norberto Fredotovich

2007-01-01

Inter epididymal testicular torsion of the spermatic cord is extremely rare and usually diagnosed at surgery. We present an unusual case of spermatic cord torsion in a 14-year-old male patient. It is important to highlight that the torsion occurred only on the distal half of the epididymis leaving the head untwisted and edematous. In addition, the fact that this condition was painless made this case extremely rare and motivated our presentation.

Testicular torsion and weather conditions: analysis of 21,289 cases in Brazil

Directory of Open Access Journals (Sweden)

Fernando Korkes

2012-04-01

Full Text Available PURPOSE: The hypothesis of association between testicular torsion and hyperactive cremasteric reflex, worsened by cold weather, has not been proved. Thirteen studies in the literature evaluated this issue, with inconclusive results. The aim of the present study was to evaluate the seasonality of testicular torsion in a large subset of patients surgically treated in Brazil, and additionally to estimate the incidence of testicular torsion. MATERIALS AND METHODS: Brazilian Public Health System Database was assessed from 1992-2010 to evaluate hospital admissions associated with treatment of testicular torsion. Average monthly temperature between 1992-2010 was calculated for each region. RESULTS: We identified 21,289 hospital admissions for treatment of testicular torsion. There was a higher number of testicular torsions during colder months (p = 0.002. To estimate the incidence of testicular torsion, we have related our findings to data from the last Brazilian census (2010. In 2010, testicular torsion occurred in 1.4:100,000 men in Brazil. CONCLUSIONS:Testicular torsion occurred at an annual incidence of approximately 1.4:100,000 men in Brazil in 2010. Seasonal variations do occur, with a significant increase of events during winter. Our findings support the theory of etiological role of cold weather to the occurrence of testicular torsion. Strategies to prevent these events can be based on these findings.

Humeral torsion revisited: a functional and ontogenetic model for populational variation.

Science.gov (United States)

Cowgill, Libby W

2007-12-01

Anthropological interest in humeral torsion has a long history, and several functional explanations for observed variation in the orientation of the humeral head have been proposed. Recent clinical studies have revived this topic by linking patterns of humeral torsion to habitual activities such as overhand throwing. However, the precise functional implications and ontogenetic history of humeral torsion remain unclear. This study examines the ontogeny of humeral torsion in a large sample of primarily immature remains from six different skeletal collections (n = 407). The results of this research confirm that humeral torsion displays consistent developmental variation within all populations of growing children; neonates display relatively posteriorly oriented humeral heads, and the level of torsion declines steadily into adulthood. As in adults, variation in the angle of humeral torsion in immature individuals varies by population, and these differences arise early in development. However, when examined in the context of the developing muscles of the shoulder complex, it becomes apparent that variation in the angle of humeral torsion is not necessarily related to specific habitual activities. Variability in this feature is more likely caused by a generalized functional imbalance between muscles of medial and lateral rotation that can be produced by a wide variety of upper limb activity patterns during growth. (c) 2007 Wiley-Liss, Inc.

Should Torsion Balance Technique Continue to be Taught to Pharmacy Students?

Science.gov (United States)

Bilger, Rhonda; Chereson, Rasma; Salama, Noha Nabil

2017-06-01

Objective. To determine the types of balances used in compounding pharmacies: torsion or digital. Methods. A survey was mailed to the pharmacist-in-charge at 698 pharmacies, representing 47% of the pharmacies in Missouri as of July 2013. The pharmacies were randomly selected and stratified by region into eight regions to ensure a representative sample. Information was gathered regarding the type and use of balances and pharmacists' perspectives on the need to teach torsion balance technique to pharmacy students. Results. The response rate for the survey was 53.3%. Out of the total responses received, those pharmacies having a torsion balance, digital balance or both were 46.8%, 27.4% and 11.8%, respectively. About 68.3% of respondents compound prescriptions. The study showed that 52% of compounding pharmacies use torsion balances in their practice. Of those with a balance in their pharmacy, 65.6% favored continuation of torsion balance instruction. Conclusions. Digital balances have become increasingly popular and have replaced torsion balances in some pharmacies, especially those that compound a significant number of prescriptions. The results of this study indicate that torsion balances remain integral to compounding practice. Therefore, students should continue being taught torsion balance technique at the college.

ESTIMATING TORSION OF DIGITAL CURVES USING 3D IMAGE ANALYSIS

Directory of Open Access Journals (Sweden)

Christoph Blankenburg

2016-04-01

Full Text Available Curvature and torsion of three-dimensional curves are important quantities in fields like material science or biomedical engineering. Torsion has an exact definition in the continuous domain. However, in the discrete case most of the existing torsion evaluation methods lead to inaccurate values, especially for low resolution data. In this contribution we use the discrete points of space curves to determine the Fourier series coefficients which allow for representing the underlying continuous curve with Cesàro’s mean. This representation of the curve suits for the estimation of curvature and torsion values with their classical continuous definition. In comparison with the literature, one major advantage of this approach is that no a priori knowledge about the shape of the cyclic curve parts approximating the discrete curves is required. Synthetic data, i.e. curves with known curvature and torsion, are used to quantify the inherent algorithm accuracy for torsion and curvature estimation. The algorithm is also tested on tomographic data of fiber structures and open foams, where discrete curves are extracted from the pore spaces.

Painless inter epididymal testicular torsion of the spermatic cord

Directory of Open Access Journals (Sweden)

Salomon V. Romano

2007-02-01

Full Text Available Inter epididymal testicular torsion of the spermatic cord is extremely rare and usually diagnosed at surgery. We present an unusual case of spermatic cord torsion in a 14-year-old male patient. It is important to highlight that the torsion occurred only on the distal half of the epididymis leaving the head untwisted and edematous. In addition, the fact that this condition was painless made this case extremely rare and motivated our presentation.

Ultrafine grained Cu processed by compression with oscillatory torsion

OpenAIRE

K. Rodak

2007-01-01

Purpose: The aim of this work is a study of Cu microstructure after severe plastic deformation process by usingcompression with oscillatory torsion test.Design/methodology/approach: Cu samples were deformed at torsion frequency (f) changed from 0 Hz(compression) to 1.8 Hz under a constant torsion angle (α) ≈8° and compression speed (v)=0.1mm/s. Structuralinvestigations were conducted by using light microscopy (LM) and transmission electron microscopy (TEM).Findings: The structural analysis ma...

Physics of detecting torsion and placing limits on its effects

International Nuclear Information System (INIS)

Stoeger, W.R.

1985-01-01

The essential principles of torsion-detection physics are presented, and an evaluation is conducted of several conceivable types of experiments and observations for actually detecting torsion fields, reemphasizing also the evident impossibility of successfully searching for its manifestations among cosmological relics. In particular, a polarized body, with net intrinsic (fundamental-particle) spin, is essential for detecting a torsion field. One which possesses only orbital angular momentum - rotation - or an unpolarized intrinsic spin density will not feel torsion. The fundamental problem in searching for such fields is the extremely small basic unit of the coupling or interaction energy between the torsion field and spin. The best way of maximizing the total interaction energy is to increase the spin density of the source sigma-s and at the same time the spin number SD of the detector. 15 references

Dynamic Bending and Torsion Stiffness Derivation from Modal Curvatures and Torsion Rates

Science.gov (United States)

MAECK, J.; DE ROECK, G.

1999-08-01

In order to maintain the reliability of civil engineering structures, considerable effort is currently spent on developing a non-destructive vibration testing method for monitoring the structural integrity of constructions. The technique must be able to observe damage, secondly to localize the damage; and finally to give an idea of the severity of the damage. Within the framework of relating changes of measured modal parameters to changes in the integrity of the structure, it is important to be able to determine the dynamic stiffness in each section of the structure from measured modal characteristics.A damaged structure results in a dynamic stiffness reduction of the cracked sections. The dynamic stiffnesses provide directly an indication of the extension of the cracked zones in the structure. The dynamic stiffness reduction can also be associated with a degree of cracking in a particular zone.In an experimental programme, a concrete beam of 6 m length is subjected to an increasing static load to produce cracks. After each static perload, the beam is tested dynamically in a free-free set-up. The change in modal parameters is then related to damage in the beam.The technique that will be presented in the paper to predict the damage location and intensity is a direct stiffness derivation from measured modal displacement derivatives. Using the bending modes, the dynamic bending stiffness can be derived from modal curvatures. Using the torsional modes, the dynamic torsion stiffness can be derived from modal torsion rates.

Torsion of abdominal appendages presenting with acute abdominal pain

International Nuclear Information System (INIS)

Al-Jaberi, Tareq M.; Gharabeih, Kamal I.; Yaghan, Rami J.

2000-01-01

Diseases of abnormal appendages are rare causes of abdominal pain in all age groups. Nine patients with torsion and infraction of abdominal appendages were retrospectively reviewed. Four patients had torsion and infarction of the appendices epiploicae, four patients had torsion and infarction of the falciform ligament. The patient with falciform ligament disease represents the first reported case of primary torsion and infarction of the falciform ligament, and the patient with the transverse colon epiplocia represents the first reported case of vibration-induced appendix epiplocia torsion and infarction. The patient with the falciform ligament disease presented with a tender upper abdominal mass and the remaining patients were operated upon with the preoperative diagnosis of acute appendicitis. The presence of normal appendix with free serosanguinous fluid in the peritoneal cavity should raise the possibility of a disease and calls for further evaluation of the intra-abdominal organs. If the diagnosis is suspected preoperatively, CT scan and ultrasound may lead to a correct diagnosis and possibly conservative management. Laparoscopy is playing an increasing diagnostic and therapeutic role in such situations. (author)

Study on reinforced lightweight coconut shell concrete beam behavior under torsion

International Nuclear Information System (INIS)

Gunasekaran, K.; Ramasubramani, R.; Annadurai, R.; Prakash Chandar, S.

2014-01-01

Highlights: • Use of coconut shell as aggregate in concrete production. • Behavior of coconut shell concrete under torsion. • Pre and post cracking behavior and analysis. • Torsional reinforcement and ductility. • Crack width and stiffness. - Abstract: This research investigates and evaluates the results of coconut shell concrete beams subjected to torsion and compared with conventional concrete beams. Eight beams, four with coconut shell concrete and four with conventional concrete were fabricated and tested. Study includes the general cracking characteristics, pre cracking behavior and analysis, post cracking behavior and analysis, minimum torsional reinforcement, torsional reinforcement, ductility, crack width and stiffness. It was observed that the torsional behavior of coconut shell concrete is comparable to that of conventional concrete. Compare to ACI prediction, equation suggested by Macgregor is more conservative in calculating cracking torsional resistance. But for the calculation of ultimate torque strength ACI prediction is more conservative compared to the equation suggested by Macgregor. Indian standard is also conservative in this regard, but it was under estimated compared to ACI and Macgregor equations. Minimum torsional reinforcement in beams is necessary to ensure that the beam do not fail at cracking. Compared to conventional concrete specimens, coconut shell concrete specimens have more ductility. Crack width at initial cracking torque for both conventional and coconut shell concrete with corresponding reinforcement ratios is almost similar

Experimental study on pure titanium during the positive-torsion and positive-negative-torsion

Energy Technology Data Exchange (ETDEWEB)

Chen, Han; Li, Fuguo, E-mail: fuguolx@nwpu.edu.cn; Li, Jinghui; Zhao, Zhen; Zhou, Shunshun; Wan, Qiong

2016-09-30

The results of the mechanical properties, microstructure and fracture analysis of the pure titanium deformed by positive-torsion (PT) and positive-negative-torsion (PNT) are investigated by uniaxial tensile (UT) test, micro-indentation (MI) test, optical microscope (OM), transmission electron microscope (TEM) and scanning electron microscope (SEM). The UT test indicates that the strength increases obviously with the increase of torsion radian during PT. However, the strength firstly increases quickly, and then tends to steady with the increase of deformation during PNT. The similar phenomena are also shown through MI hardness analysis. The results from geometrically necessary dislocations (GNDs) and statistically stored dislocations (SSDs) indicate that the dislocation density varies differently with the increase of deformation during PT and PNT. OM observation shows the grains are elongated and large numbers of deformation twins are observed during PT while the equiaxial grains are always presented during PNT. The variations of dislocation density during PT and PNT are verified by TEM. Besides, quantities of subgrains (SGs) are observed owing to the accumulated larger plastic strain during PNT while large numbers of deformation twins intersect with each other during PT. The fracture analysis indicates that large numbers of micro-voids distribute non-uniformly on fracture surface of sample twisted by PNT. However, the characteristics of ductile and brittle fracture are observed on fracture surface of sample twisted by PT.

Transitional Failure of Carbon Nanotube Systems under a Combination of Tension and Torsion

OpenAIRE

Jeong, Byeong-Woo

2012-01-01

Transitional failure envelopes of single- and double-walled carbon nanotubes under combined tension-torsion are predicted using classical molecular dynamics simulations. The observations reveal that while the tensile failure load decreases with combined torsion, the torsional buckling moment increases with combined tension. As a result, the failure envelopes under combined tension-torsion are definitely different from those under pure tension or torsion. In such combined loading, there is a m...

Perinatal testicular torsion: literature review and local experience ...

African Journals Online (AJOL)

The prognosis in TUDT is guarded and contralateral fixation was not practiced, except in a 5-week-old infant. Early orchiopexy at 3–6 months is recommended. Cooperation between surgeons, neonatologists, and parents is mandatory to avoid time delay. Keywords: intrauterine testicular torsion, postnatal testicular torsion, ...

Transitional Failure of Carbon Nanotube Systems under a Combination of Tension and Torsion

Directory of Open Access Journals (Sweden)

Byeong-Woo Jeong

2012-01-01

Full Text Available Transitional failure envelopes of single- and double-walled carbon nanotubes under combined tension-torsion are predicted using classical molecular dynamics simulations. The observations reveal that while the tensile failure load decreases with combined torsion, the torsional buckling moment increases with combined tension. As a result, the failure envelopes under combined tension-torsion are definitely different from those under pure tension or torsion. In such combined loading, there is a multitude of failure modes (tensile failure and torsional buckling, and the failure consequently exhibits the feature of transitional failure envelopes. In addition, the safe region of double-walled carbon nanotubes is significantly larger than that of single-walled carbon nanotubes due to the differences in the onset of torsional buckling.

New curvature-torsion relations through decomposition of the Bianchi identities

International Nuclear Information System (INIS)

Davies, J.B.

1988-01-01

The Bianchi Identities relating asymmetric curvature to torsion are obtained as a new set of equations governing second-order curvature tensors. The usual contribution of symmetric curvature to the gravitational field is found to be a subset of these identities though with an added contribution due to torsion gradients. The antisymmetric curvature two-tensor is shown to be related to the divergence of the torsion. Using a model of particle-antiparticle pair production, identification of certain torsion components with electroweak fields is proposed. These components obey equations, similar to Maxwell's that are subsets of these linear Bianchi identities. These results are shown to be consistent with gauge and other previous analyses

Studies of DNA supercoiling in vivo and in vitro

Energy Technology Data Exchange (ETDEWEB)

Cook, D.N.

1990-10-01

This thesis describes a number of diverse experiments whose common theme is to elaborate some aspect of DNA supercoiling. The torsion elastic constant of DNA is measure as a function of superhelix density using the technique of picosecond Time Resolved Fluorescence Polarization Anisotropy (FPA) of intercalated ethidium bromide. The results agree with theories which predict that the anisotropy decay should vary with the square root of the relative viscosity. This experiment furthermore demonstrates a sensitivity of FPA to a change in torsion elastic constant of less than 10%. A number of covalently closed DNA samples, ranging in superhelix density from = [minus]0.123 to [plus]0.042, are then examined. A novel method for measuring changes in local supercoiling on a large PNA molecule which is sensitive to changes in supercoiling of regions of chromosomal DNA as short as 1 kilobase in length is presented. Study of chromosomal supercoiling regulating anaerobic gene expression in the facultative photosynthetic bacterium, Rhodobacter capsulatus showed that no stable change in chromosomal supercoiling upon a shift from aerobic respiratory growth to anaerobic photosynthetic conditions. Studies to detect transient changes in DNA supercoiling indicate that DNA downstream from heavily transcribed genes for the photosynthetic reaction center are relaxed or perhaps overwound upon the induction of photosynthetic metabolism. These results are interpreted in terms of the twin domain model of transcriptional supercoiling.

Studies of DNA supercoiling in vivo and in vitro

Energy Technology Data Exchange (ETDEWEB)

Cook, David Nelson [Univ. of California, Berkeley, CA (United States)

1990-10-01

This thesis describes a number of diverse experiments whose common theme is to elaborate some aspect of DNA supercoiling. The torsion elastic constant of DNA is measure as a function of superhelix density using the technique of picosecond Time Resolved Fluorescence Polarization Anisotropy (FPA) of intercalated ethidium bromide. The results agree with theories which predict that the anisotropy decay should vary with the square root of the relative viscosity. This experiment furthermore demonstrates a sensitivity of FPA to a change in torsion elastic constant of less than 10%. A number of covalently closed DNA samples, ranging in superhelix density from = -0.123 to +0.042, are then examined. A novel method for measuring changes in local supercoiling on a large PNA molecule which is sensitive to changes in supercoiling of regions of chromosomal DNA as short as 1 kilobase in length is presented. Study of chromosomal supercoiling regulating anaerobic gene expression in the facultative photosynthetic bacterium, Rhodobacter capsulatus showed that no stable change in chromosomal supercoiling upon a shift from aerobic respiratory growth to anaerobic photosynthetic conditions. Studies to detect transient changes in DNA supercoiling indicate that DNA downstream from heavily transcribed genes for the photosynthetic reaction center are relaxed or perhaps overwound upon the induction of photosynthetic metabolism. These results are interpreted in terms of the twin domain model of transcriptional supercoiling.

Severe congenital penile torsion with anterior urethral diverticulum: A case report

Directory of Open Access Journals (Sweden)

Amilal Bhat

2018-03-01

Full Text Available Introduction: We present a rare case of severe penile torsion of 180° along with giant congenital anterior urethral diverticula. Presentation of these two rare anomalies together is extremely rare and has not been reported yet. The extreme rarity of the case and its management warrants this presentation. Observation: A 5 years old boy presented to us as a case of epispadias with post-void dribbling and wetting of the underwears. On examination, he was found to be a case of severe congenital penile torsion with diversion and rotation of median raphae in a counterclockwise fashion upto the midline dorsally confirming 180° torsion. During voiding, there was appearance of a swelling in distal penile region with passage of urinary drops while compressing it. Micturating cystourethrogram showed diverticula in penile and bulbar urethra. Torsion was completely corrected by penile de-gloving in a plane between two layers of buck fascia and mobilization of the urethra along with spongiosum proximally upto the penoscrotal junction and distally upto the glans. Diverticula was laid open and underwent urethroplasty along with double breasting of thickened diverticular tissue. Torsion was completely corrected after surgery. Post-operative recovery was uneventful. Urine culture was sterile and uroflowmetry showed maximal urinary flow of 12 ml/s at 3 months postoperatively. Conclusions: Penile de-gloving and adequate urethral mobilization corrects the severe penile torsion of 180°. Correction of severe torsion and urethroplasty is feasible in a single stage with good results. Keywords: Penile torsion, Urethral diverticula, Congenital anomalies, Mobilization of urethra, Urethroplasty, Double Breasting, Correction of penile torsion

On the properties of torsions in Riemann-Cartan space-times

International Nuclear Information System (INIS)

Baker, W.M.; Atkins, W.K.; Davis, W.R.

1978-01-01

This paper is the first paper in a series of three papers dealing with the physical properties of torsions in Riemann-Cartan space-times (U 4 ). Paper one deals with the particular types of torsion that can be associated with the U 4 reinterpretation of a special class of null electromagnetic solutions of the standard form of Einstein's equations. In particular, for plane null electromagnetic solutions, three types of torsion solutions are associated with this type of reinterpretation. Two of these solutions, the trivector and semi-symmetric torsions, although rather special, serve as examples of what could be done to find the associated torsions in terms of simple requirements on identities in U 4 . The third class is obtained by relating the contorsion to the Lanczos ''spin'' tensor. Paper two, dealing with gravitational radiation, provides the proper background relating to the physical significance of the Lanczos tensor. This series of papers is primarily concerned with the question of the possible physical role of all types of torsion, compatible with an extension or an U 4 reinterpretation of Einstein's theory, consistent with the broadest possible interpretation of the present form of the Einstein-Cartan-Sciama-Kibble theory. However, in paper three some consideration will be given on theories with simpler metrical generalizations of U 4 and the related types of torsion. We emphasize that the content of paper one and two should be viewed mainly as special formal results that introduce the more general considerations of paper three

Disintegration of cruciform and G-quadruplex structures during the course of helicase-dependent amplification (HDA).

Science.gov (United States)

Li, Dawei; Lv, Bei; Zhang, Hao; Lee, Jasmine Yiqin; Li, Tianhu

2015-04-15

Unlike chemical damages on DNA, physical alterations of B-form of DNA occur commonly in organisms that serve as signals for specified cellular events. Although the modes of action for repairing of chemically damaged DNA have been well studied nowadays, the repairing mechanisms for physically altered DNA structures have not yet been understood. Our current in vitro studies show that both breakdown of stable non-B DNA structures and resumption of canonical B-conformation of DNA can take place during the courses of isothermal helicase-dependent amplification (HDA). The pathway that makes the non-B DNA structures repairable is presumably the relieving of the accumulated torsional stress that was caused by the positive supercoiling. Our new findings suggest that living organisms might have evolved this distinct and economical pathway for repairing their physically altered DNA structures. Copyright © 2015 Elsevier Ltd. All rights reserved.

Severe congenital penile torsion with anterior urethral diverticulum ...

African Journals Online (AJOL)

On examination, he was found to be a case of severe congenital penile torsion with diversion and rotation of median raphae in a counterclockwise fashion upto the midline dorsally confirming 180◦ torsion. During voiding, there was appearance of a swelling in distal penile region with passage of urinary drops while ...

Torsion of wandering spleen in patient with horseshoe kidney

International Nuclear Information System (INIS)

Molski, St.; Zurada, A.; Meder, G.; Lasek, W.

2005-01-01

Wandering spleen is rare pathology, mostly occurring in young women. Disease may be congenital or acquired. Absence or laxity of ligaments leads to spleen pathologic mobility and may cause torsion of its pedicle, resulting in ischemia or infarct even haemorrhagic shock and patients death. We report a case of young woman previously diagnosed (and treated nonoperative) with wandering spleen who presented acute abdomen after minor blunt trauma. She was evaluated with abdominal ultrasound (US) and spiral computed tomography (CT). Torsion of splenic pedicle and splenic rupture was diagnosed and a horseshoe kidney as well. Laparotomy followed by splenectomy confirmed the existence of an intrapelvic torsioned wandering spleen. The only definitive treatment of wandering spleen is operative since nonoperative treatment is associated with high complication rate. Earlier diagnosis of wandering spleen in asymptomatic patients lets to direct diagnosis when patient starts to present with acute abdomen. CT and abdominal US play most important role in diagnosing splenic pedicle torsion. To our knowledge this is a first case of torsion of splenic pedicle in patient with horseshoe kidney. We consider this coincidence to be a congenital defect as both conditions may develop in second month gestation. (author)

Standardized education and parental awareness are lacking for testicular torsion.

Science.gov (United States)

Friedman, Ariella A; Ahmed, Haris; Gitlin, Jordan S; Palmer, Lane S

2016-06-01

Testicular torsion leads to orchiectomy in 30-50% of cases, which may cause psychological upset and parental guilt over a potentially avertable outcome. Presentation delay is an important modifiable cause of orchiectomy; yet, families are not routinely educated about torsion or its urgency. The present study assessed parental knowledge regarding acute scrotal pain. An anonymous survey was distributed to parents in Urology and ENT offices, asking about their children's gender and scrotal pain history, urgency of response to a child's acute scrotal pain, and familiarity with testicular torsion. Surveys of 479 urology and 59 ENT parents were analyzed. The results between the two were not statistically different. Among the urology parents, 34% had heard of testicular twisting/torsion, most commonly through friends, relatives or knowing someone with torsion (35%); only 17% were informed by pediatricians (Summary Figure). Parents presenting for a child's scrotal pain were significantly more likely to have heard of torsion (69%) than those presenting for other reasons (30%, OR 5.24, P parents of boys had spoken with their children about torsion. Roughly three quarters of them would seek emergent medical attention - by day (75%) or night (82%) - for acute scrotal pain. However, urgency was no more likely among those who knew about torsion. This was the first study to assess parental knowledge of the emergent nature of acute scrotal pain in a non-urgent setting, and most closely approximating their level of knowledge at the time of pain onset. It also assessed parents' hypothetical responses to the scenario, which was markedly different than documented presentation times, highlighting a potential area for improvement in presentation times. Potential limitations included lack of respondent demographic data, potential sampling bias of a population with greater healthcare knowledge or involvement, and assessment of parents only. Parental knowledge of testicular torsion was

Risk relievers and customer brand preference in the purchase of cars

African Journals Online (AJOL)

Seventeen risk-relievers were found to be suitable in purchase of cars. The study purported to find out the more influencing risk reducers among the chosen seventeen risk relievers in purchase of cars. Secondly the study tries to find out the impact of risk relievers based on brand choice. Seven brands namely Maruti, Tata, ...

Testicular Torsion (For Parents)

Science.gov (United States)

... Parents Kids Teens Hernias Ultrasound: Scrotum Undescended Testicles Male Reproductive System PQ: I have a lump on one of ... to Do a Testicular Self-Exam (Slideshow) Varicocele Male Reproductive System Testicular Torsion View more About Us Contact Us ...

Deep learning methods for protein torsion angle prediction.

Science.gov (United States)

Li, Haiou; Hou, Jie; Adhikari, Badri; Lyu, Qiang; Cheng, Jianlin

2017-09-18

Deep learning is one of the most powerful machine learning methods that has achieved the state-of-the-art performance in many domains. Since deep learning was introduced to the field of bioinformatics in 2012, it has achieved success in a number of areas such as protein residue-residue contact prediction, secondary structure prediction, and fold recognition. In this work, we developed deep learning methods to improve the prediction of torsion (dihedral) angles of proteins. We design four different deep learning architectures to predict protein torsion angles. The architectures including deep neural network (DNN) and deep restricted Boltzmann machine (DRBN), deep recurrent neural network (DRNN) and deep recurrent restricted Boltzmann machine (DReRBM) since the protein torsion angle prediction is a sequence related problem. In addition to existing protein features, two new features (predicted residue contact number and the error distribution of torsion angles extracted from sequence fragments) are used as input to each of the four deep learning architectures to predict phi and psi angles of protein backbone. The mean absolute error (MAE) of phi and psi angles predicted by DRNN, DReRBM, DRBM and DNN is about 20-21° and 29-30° on an independent dataset. The MAE of phi angle is comparable to the existing methods, but the MAE of psi angle is 29°, 2° lower than the existing methods. On the latest CASP12 targets, our methods also achieved the performance better than or comparable to a state-of-the art method. Our experiment demonstrates that deep learning is a valuable method for predicting protein torsion angles. The deep recurrent network architecture performs slightly better than deep feed-forward architecture, and the predicted residue contact number and the error distribution of torsion angles extracted from sequence fragments are useful features for improving prediction accuracy.

Spontaneous formation of non-uniform double helices for elastic rods under torsion

International Nuclear Information System (INIS)

Li, Hongyuan; Zhao, Shumin; Xia, Minggang; He, Siyu; Yang, Qifan; Yan, Yuming; Zhao, Hanqiao

2017-01-01

The spontaneous formation of double helices for filaments under torsion is common and significant. For example, the research on the supercoiling of DNA is helpful for understanding the replication and transcription of DNA. Similar double helices can appear in carbon nanotube yarns, cables, telephone wires and so forth. We noticed that non-uniform double helices can be produced due to the surface friction induced by the self-contact. Therefore an ideal model was presented to investigate the formation of double helices for elastic rods under torque. A general equilibrium condition which is valid for both the smooth surface and the rough surface situations is derived by using the variational method. By adding further constraints, the smooth and rough surface situations are investigated in detail respectively. Additionally, the model showed that the specific process of how to twist and slack the rod can determine the surface friction and hence influence the configuration of the double helix formed by rods with rough surfaces. Based on this principle, a method of manufacturing double helices with designed configurations was proposed and demonstrated. Finally, experiments were performed to verify the model and the results agreed well with the theory. - Highlights: • An ideal model is conceived to investigate the spontaneous formation of double helices for rods under torsion. • Variational method is used to obtain a universal result for the double helix formation process • Self-contact and surface friction is considered to analyze the non-uniform double helix. • A novel method of producing double helix with arbitrary configuration is proposed and demonstrated. • The experiment results agree well with the theory.

Spontaneous formation of non-uniform double helices for elastic rods under torsion

Energy Technology Data Exchange (ETDEWEB)

Li, Hongyuan [Department of Applied Physics, School of Science, Xi' an Jiaotong University, Shaanxi 710049 (China); Zhao, Shumin, E-mail: zhaosm@mail.xjtu.edu.cn [Department of Applied Physics, School of Science, Xi' an Jiaotong University, Shaanxi 710049 (China); Xia, Minggang [Department of Optical Information Science and Technology, School of Science, Xi' an Jiaotong University, 710049 (China); Laboratory of Nanostructure and Physics Properties, School of Science, Xi' an Jiaotong University, 710049 (China); He, Siyu [Department of Applied Physics, School of Science, Xi' an Jiaotong University, Shaanxi 710049 (China); Yang, Qifan [Department of Biomedical Engineering, School of Life Science and Technology, Xi' an Jiaotong University, Shaanxi 710049 (China); Yan, Yuming [Department of Electrical Engineering and Automation, School of Electrical Engineering, Xi' an Jiaotong University, Shaanxi 710049 (China); Zhao, Hanqiao [Department of Biomedical Engineering, School of Life Science and Technology, Xi' an Jiaotong University, Shaanxi 710049 (China)

2017-02-19

The spontaneous formation of double helices for filaments under torsion is common and significant. For example, the research on the supercoiling of DNA is helpful for understanding the replication and transcription of DNA. Similar double helices can appear in carbon nanotube yarns, cables, telephone wires and so forth. We noticed that non-uniform double helices can be produced due to the surface friction induced by the self-contact. Therefore an ideal model was presented to investigate the formation of double helices for elastic rods under torque. A general equilibrium condition which is valid for both the smooth surface and the rough surface situations is derived by using the variational method. By adding further constraints, the smooth and rough surface situations are investigated in detail respectively. Additionally, the model showed that the specific process of how to twist and slack the rod can determine the surface friction and hence influence the configuration of the double helix formed by rods with rough surfaces. Based on this principle, a method of manufacturing double helices with designed configurations was proposed and demonstrated. Finally, experiments were performed to verify the model and the results agreed well with the theory. - Highlights: • An ideal model is conceived to investigate the spontaneous formation of double helices for rods under torsion. • Variational method is used to obtain a universal result for the double helix formation process • Self-contact and surface friction is considered to analyze the non-uniform double helix. • A novel method of producing double helix with arbitrary configuration is proposed and demonstrated. • The experiment results agree well with the theory.

Frequency-dependent solvent friction and torsional damping in liquid 1,2-difluoroethane

Science.gov (United States)

MacPhail, Richard A.; Monroe, Frances C.

1991-04-01

We have used Raman spectroscopy to study the torsional dynamics, rotational dynamics, and conformational solvation energy of liquid 1,2-difluoroethane. From the Raman intensities, we obtain Δ H(g-t) = -2.4±0.1 kcal/mol, indicating strong dipolar solvation of the gauche conformer. We analyze the Raman linewidths of the CCF bending bands to obtain the zero-frequency torsional damping coefficient or well friction for the gauche conformer, and from the linewidth of the torsion band we obtain the friction evaluated at the torsional frequency. The zero-frequency well friction shows deviations from hydrodynamic behavior reminiscent of those observed for barrier friction, whereas the high-frequency friction is considerably smaller in magnitude and independent of temperature and viscosity. The zero-frequency torsional friction correlates linearly with the rotational friction. It is argued that the small amplitude of the torsional fluctuations emphasizes the short distance, or high wavevector components of the solvent friction. Dielectric friction apparently does not contribute to the torsional friction at the observed frequencies.

Torsion of the gallbladder: a case report

Directory of Open Access Journals (Sweden)

Ijaz Samia

2008-07-01

Full Text Available Abstract Introduction Torsion of the gallbladder is a rare condition that most commonly affects the elderly. Pre-operative diagnosis is the exception rather than the rule. Any delay in treatment can be fatal as the gallbladder may rupture, leading to biliary peritonitis. Case presentation We present the case of an 80-year-old woman who was admitted with right upper quadrant pain initially thought to be secondary to acute cholecystitis. Subsequent ultrasound and computed tomography scans of the abdomen revealed signs suggestive of acute cholecystitis but neither modality detected any gallstones. As the patient's symptoms failed to resolve on conservative management, she was taken to theatre for an open cholecystectomy. Intra-operatively, the gallbladder had undergone complete torsion and appeared gangrenous. A routine cholecystectomy followed and she recovered from the operation without incident. Conclusion It is rare to diagnose torsion of the gallbladder pre-operatively despite advances in diagnostic imaging. However, this differential diagnosis should be borne in mind particularly in the elderly patient, without proven gallstones, who fails to improve on conservative management. An emergency cholecystectomy is indicated in the event of diagnosing torsion of the gallbladder to avert the potentially lethal sequelae of biliary peritonitis.

Ultrasonographic diagnosis of torsion of testicular appendages

International Nuclear Information System (INIS)

Esparza, J.; Gonzalez, A.; Cordero, J. L.

2000-01-01

To determine the efficacy of ultrasound in boys presenting torsion of a testicular appendage. A series of 30 boys with acute scrotal pain due to torsion of a testicular appendage was studied. Nine patients underwent surgery. The clinical findings and course in the remaining 21 suggested the presence of this abnormality. All of them underwent conventional and color Doppler ultrasound using a 7.5 MHz transducer. In 15 boys, ultrasound images depicted the affected appendage as a mass between the epididymal head and the testicle. In 13 cases, only signs of a inflammatory reaction, with enlargement of the epididymal head and tunicas presenting hyperflow and hydrocele, mimicking acute epididymities. In two cases, the images were normal. There is no definitive, distinguishing ultrasound image corresponding to testicular appendage torsion. Therefore, this diagnostic technique should be accompanied by clinical assessment. (Author) 14 refs

DNA supercoiling: changes during cellular differentiation and activation of chromatin transcription

International Nuclear Information System (INIS)

Luchnik, A.N.; Bakayev, V.V.; Glaser, V.M.; Moscow State Univ., USSR)

1983-01-01

In this paper it is reported that elastic DNA torsional tension has been observed in a fraction of isolated SV40 minichromosomes, which are shown to be transcriptionally active, and that the number of DNA topological (titratable superhelical) turns in closed superhelical loops of nuclear DNA decreases during cellular differentiation, which, we propose, may be responsible for the coordinate switch in transcription of genes controlling cellular proliferation. 37 references, 6 figures, 2 tables

Torsional stresses in the transverse fillet weld tubular joints

NARCIS (Netherlands)

Gunay, D.; Aydemir, A.; Özer, H.

1996-01-01

Torsional stresses, 'tre and tel , in tbe transverse fillet tubular weld joint subjected to torsional load have been analyzed by the finite element method using triangular and quadrilateral izoparametric axisymmetric fourier type torus finite elements. There is an axisymmetry with respect to

Peening as a stress relieving method for welded joints

International Nuclear Information System (INIS)

Ferreira, M.L.R.

1984-01-01

The efficacy of the process of stress relieving by hammer-peening, in heavy plates of low carbon steel is analysed. The effects of peening in the mechanical properties of welded metal deposited by shield metal arc welding, using the electrodes E-6010, E-7018 and E-8018C-2, and the weld metal deposited by submerged arc welding, using the filler metals ENil and EA3, are also analysed. X-ray diffraction was used in order to verify the efficacy of peening as a stress-relieving process. The obtained results and the literature reviewed show that, peening is effective in stress relieving. (author) [pt

Isolated Fallopian Tube Torsion in Adolescents

Directory of Open Access Journals (Sweden)

S. Rajaram

2013-01-01

Full Text Available Background. Fallopian tube torsion is a rare cause of acute abdomen, occurring commonly in females of reproductive age. It lacks pathognomonic symptoms, signs, or imaging features, thus causing delay in surgical intervention. Case. We report two cases of isolated fallopian tube torsion in adolescent girls. In the first case a 19-year-old patient presented with acute pain in the left iliac region associated with episodes of vomiting for one day and mild tenderness on examination. Laparoscopy revealed left sided twisted fallopian tube associated with hemorrhagic cyst of ovary. The tube was untwisted and salvaged. In another case an 18-year-old virgin girl presented with similar complaints since one week, associated with mild tenderness in the lower abdomen and tender cystic mass on per rectal examination. On laparoscopy right twisted fallopian tube associated with a paratubal cyst was found. Salpingectomy was done as the tube was gangrenous. Conclusion. Fallopian tube torsion, though rare, should be considered in women of reproductive age with unilateral pelvic pain. Early diagnostic laparoscopy is important for an accurate diagnosis and could salvage the tube.

Spin-torsion effects in the hyperfine structure of methanol

International Nuclear Information System (INIS)

Coudert, L. H.; Gutlé, C.; Huet, T. R.; Grabow, J.-U.; Levshakov, S. A.

2015-01-01

The magnetic hyperfine structure of the non-rigid methanol molecule is investigated experimentally and theoretically. 12 hyperfine patterns are recorded using molecular beam microwave spectrometers. These patterns, along with previously recorded ones, are analyzed in an attempt to evidence the effects of the magnetic spin-torsion coupling due to the large amplitude internal rotation of the methyl group [J. E. M. Heuvel and A. Dymanus, J. Mol. Spectrosc. 47, 363 (1973)]. The theoretical approach setup to analyze the observed data accounts for this spin-torsion in addition to the familiar magnetic spin-rotation and spin-spin interactions. The theoretical approach relies on symmetry considerations to build a hyperfine coupling Hamiltonian and spin-rotation-torsion wavefunctions compatible with the Pauli exclusion principle. Although all experimental hyperfine patterns are not fully resolved, the line position analysis yields values for several parameters including one describing the spin-torsion coupling

The physics of detecting torsion and placing limits on its effects

International Nuclear Information System (INIS)

Stoeger, W.R.

1985-01-01

The essential principles of torsion-detection physics are presented and several conceivable types of experiments and observations for actually detecting torsion fields are evaluated reemphasizing also the evident impossibility of successfully searching for its manifestations among cosmological relics. In particular, a polarized body, with net intrinsic (fundamental-particle) spin, is essential for detecting a torsion field. One which possesses only orbital angular momentum-rotation-or an unpolarized intrinsic spin density will not feel torsion. The fundamental problem in searching for such fields is the extremely small basic unit of the coupling or interaction energy between the torsion field and spin, epsilonapprox.(8πG'/c 2 )(h 2 /4). The best way of maximizing the total interaction energy is to increase the spin density of the source σ 5 and, at the same time the ''spin number'' Ssub(D) of the detector. (author)

Torsion effect on fully developed flow in a helical pipe

Science.gov (United States)

Kao, Hsiao C.

1987-01-01

Two techniques, a series expansion method of perturbed Poiseuille flow valid for low Dean numbers and a solution of the complete Navier-Stokes equation applicable to intermediate Dean values, are used to investigate the torsion effect on the fully developed laminar flow in a helical pipe of constant circular cross section. For the secondary flow patterns, the results show that the presence of torsion can produce a significant effect if the ratio of the curvature to the torsion is of order unity. The secondary flow is distorted in these cases. It is noted that the torsion effect is, however, usually small, and that the secondary flow has the usual pattern of a pair of counter-rotating vortices of nearly equal strength.

Testicular torsion

DEFF Research Database (Denmark)

Brasso, K; Andersen, L; Kay, L

1993-01-01

Thirty-five patients were examined 6-11 years after operation for torsion of the testis. Loss of testicular tissue was significantly associated with long preoperative duration of symptoms and with low postoperative sperm counts. The sex hormones were normal in the majority of patients...... to the sperm count and concentration. Measurement of carnitine levels in seminal plasma, as a sign of vas deferens obstruction or dysfunction of epididymis, and of autoantibodies against spermatozoa revealed no significant findings....

Gastric dilatation-volvulus after splenic torsion in two dogs.

Science.gov (United States)

Millis, D L; Nemzek, J; Riggs, C; Walshaw, R

1995-08-01

Two dogs developed gastric dilatation-volvulus 2 and 17 months, respectively, after splenectomy for treatment of splenic torsion. Splenic displacement and torsion may stretch the gastric ligaments, allowing increased mobility of the stomach. After splenectomy, an anatomic void may be created in the cranioventral part of the abdomen, contributing to the mobility of the stomach. Veterinarians treating dogs with isolated splenic torsion may wish to consider prophylactic gastropexy at splenectomy, to reduce the chance of future gastric dilatation-volvulus. Prophylactic gastropexy should be done only if the dog's hemodynamic status is stable enough to allow for performance of the additional surgery.

[Torsion of wandering spleen in a teenager: about a case].

Science.gov (United States)

Dème, Hamidou; Akpo, Léra Géraud; Fall, Seynabou; Badji, Nfally; Ka, Ibrahima; Guèye, Mohamadou Lamine; Touré, Mouhamed Hamine; Niang, El Hadj

2016-01-01

Wandering or migrating spleen is a rare anomaly which is usually described in children. Complications, which include pedicle torsion, are common and can be life-threatening. We report the case of a 17 year-old patient with a long past medical history of epigastric pain suffering from wandering spleen with chronic torsion of the pedicle. The clinical picture was marked by spontaneously painful epigastric mass, evolved over the past 48 hours. Abdominal ultrasound objectified heterogeneous hypertrophied ectopic spleen in epigastric position and a subcapsular hematoma. Doppler showed a torsion of splenic pedicle which was untwisted 2 turns and a small blood stream on the splenic artery. Abdominal CT scan with contrast injection showed a lack of parenchymal enhancement of large epigastric ectopic spleen and a subcapsular hematoma. The diagnosis of wandering spleen with chronic torsion of the pedicle complicated by necrosis and subcapsular hematoma was confirmed. The patient underwent splenectomy. The postoperative course was uneventful. We here discuss the contribution of ultrasound and CT scan in the diagnosis of wandering spleen with chronic torsion of the pedicle.

Thermal stress relieving of dilute uranium alloys

International Nuclear Information System (INIS)

Eckelmeyer, K.H.

1980-01-01

The kinetics of thermal stress relieving of uranium - 2.3 wt. % niobium, uranium - 2.0 wt. % molybdenum, and uranium - 0.75 wt. % titanium are reported and discussed. Two temperature regimes of stress relieving are observed. In the low temperature regime (T 0 C) the process appears to be controlled by an athermal microplasticity mechanism which can be completely suppressed by prior age hardening. In the high temperature regime (300 0 C 0 C) the process appears to be controlled by a classical diffusional creep mechanism which is strongly dependent on temperature and time. Stress relieving is accelerated in cases where it occurs simultaneously with age hardening. The potential danger of residual stress induced stress corrosion cracking of uranium alloys is discussed. It is shown that the residual stress relief which accompanies age hardening of uranium - 0.75% titanium more than compensates for the reduction in K/sub ISCC/ caused by aging. As a result, age hardening actually decreases the susceptibility of this alloy to residual stress induced stress corrosion cracking

Torsion of the fallopian tube--a late complication of sterilisation.

Science.gov (United States)

Sivanesaratnam, V

1986-02-01

Torsion of an intact fallopian tube, unaccompanied by torsion of the ipsilateral ovary, was noted as a complication of bilateral tubal occlusion by the Pomeroy method in a 45-year old Indian woman. The sterilization was performed 5 years previously, at the time of Cesarean section delivery. The patient presented with a history of pain in the right iliac fossa. Laparotomy showed that the distal segment of the right fallopian tube was twisted 3 times on the distal mesosalpinx and appeared tense and gangrenous. The right ovary was normal and a 2 cm gap was noted between the proximal and distal segments of the tube. As a rare complication of the Pomeroy method, the gap in the tube can allow the distal mesosalpinx to act as a pedicle, and with a long mesosalpinx, the fimbriated segment of the tube lies free and may swing and twist to produce torsion. The occurrence of torsion is further promoted by a vascular disturbance leading to venous congestion, edema, and increased weight of the free fimbrial end of the tube. In those patients with a history of sterilization, torsion of the fallopian tube should be considered in the differential diagnosis of acute lower abdominal pain. Torsion of the fallopian tube has also been reported following other methods of tubal occlusion, including cautery and clips.

Aerodynamic stability of long span suspension bridges with low torsional natural frequencies

DEFF Research Database (Denmark)

Andersen, Michael Styrk; Johansson, Jens; Brandt, Anders

2016-01-01

tests where the torsional frequency was lower than the vertical. But too low torsional stiffness caused large static displacements of the girder at medium–high wind speeds and steady state oscillations driven by a combination of torsional divergence and stalling behavior at the critical wind seed...

RELIEVE: A FORTRAN 77 program for numerical and graphical processing of digital topographic maps; RELIEVE: Un programa FORTRAN para procesamiento numerico y grafico de mapas topograficos digitalizados

Energy Technology Data Exchange (ETDEWEB)

Sanchez, J.J.; Gorostiza, C.

1995-07-01

The RELIEVE program was developed in order to its integration with the expert system SIRENAS, in the frame of the Industrial Risks Programme, within the CIEMAT center. For accomplishing this mentioned system, arose the necessity of an additional component enabled for analyzing the topography (relieve) of the territory in which the focused site is located. That is just the mission of the RELIEVE program. Basically RELIEVE analyses the digitalized data points of a determinate topographic area, around a location of interest. The program allows us estimation by numerical techniques, using IMSL library, of the deep width, and other geometrical characteristics of the valley that is involved in. Optionally RELIEVE produces also graphical outputs concerning 3D representation of topographical map, level curves, sections of interest considered in the valley, etc., by means of the DISSPLA II library, running in the IBM system of the CIEMAT. (Author) 5 refs.

RELIEVE: A FORTRAN 77 program for numerical and graphical processing of digital topographic maps; RELIEVE: Un programa FORTRAN para procesamiento numerico y grafico de mapas topograficos digitalizados

Energy Technology Data Exchange (ETDEWEB)

Sanchez, J.J.; Gorostiza, C.

1995-12-01

The RELIEVE program was developed in order to its integration with the expert system SIRENAS, in the frame of the Industrial Risks Programme, within the CIEMAT center. For accomplishing this mentioned system, arose the necessity of an additional component unable for analyzing the topography (relieve) of the territory in which the focused site is located. That one is just the mission of the RELIEVE program. Basically RELIEVE analyses the digitalized data points of a determined topographic area, around a location of interest. The program allows us estimation by numerical techniques, using IMSL library, of the deep width, and other geometrical characteristics of the valley that are involved in. Optionally RELIEVE produces also graphical outputs concerning 3D representation of topographical map, level curves, sections of interest considered in the valley, etc., by means of the DISSPLA II library, running in the IBM system of the CIEMAT. (Author)

Torsional Dynamics of Steerable Needles: Modeling and Fluoroscopic Guidance

Science.gov (United States)

Swensen, John P.; Lin, MingDe; Okamura, Allison M.; Cowan, Noah J.

2017-01-01

Needle insertions underlie a diversity of medical interventions. Steerable needles provide a means by which to enhance existing needle-based interventions and facilitate new ones. Tip-steerable needles follow a curved path and can be steered by twisting the needle base during insertion, but this twisting excites torsional dynamics that introduce a discrepancy between the base and tip twist angles. Here, we model the torsional dynamics of a flexible rod—such as a tip-steerable needle—during subsurface insertion and develop a new controller based on the model. The torsional model incorporates time-varying mode shapes to capture the changing boundary conditions inherent during insertion. Numerical simulations and physical experiments using two distinct setups—stereo camera feedback in semi-transparent artificial tissue and feedback control with real-time X-ray imaging in optically opaque artificial tissue— demonstrate the need to account for torsional dynamics in control of the needle tip. PMID:24860026

[The functional sport shoe parameter "torsion" within running shoe research--a literature review].

Science.gov (United States)

Michel, F I; Kälin, X; Metzger, A; Westphal, K; Schweizer, F; Campe, S; Segesser, B

2009-12-01

Within the sport shoe area torsion is described as the twisting and decoupling of the rear-, mid- and forefoot along the longitudinal axis of the foot. Studies have shown that running shoes restrict the torsion of the foot and thus they increase the pronation of the foot. Based on the findings, it is recommended to design running shoes, which allow the natural freedom of movement of the foot. The market introduction of the first torsion concept through adidas(R) took place in 1989. Independently of the first market introduction, only one epidemiological study was conducted in the running shoe area. The study should investigate the occurrence of Achilles tendon problems of the athletes running in the new "adidas Torsion(R) shoes". However, further studies quantifying the optimal region of torsionability concerning the reduction of injury incidence are still missing. Newer studies reveal that the criterion torsion only plays a secondary roll regarding the buying decision. Moreover, athletes are not able to perceive torsionability as a discrete functional parameter. It is to register, that several workgroups are dealing intensively with the detailed analysis of the foot movement based on kinematic multi-segment-models. However, scientific as well as popular scientific contributions display that the original idea of the torsion concept is still not completely understood. Hence, the "inverse" characteristic is postulated. The present literature review leads to the deduction that the functional characteristics of the torsion concept are not fully implemented within the running shoe area. This implies the necessity of scientific studies, which investigate the relevance of a functional torsion concept regarding injury prevention based on basic and applied research. Besides, biomechanical studies should analyse systematically the mechanism and the effects of torsion relevant technologies and systems.

Acute torsion and ischemia of the appendix in a young child

Directory of Open Access Journals (Sweden)

Dhruvin H. Hirpara

2018-04-01

Full Text Available Torsion of the vermiform appendix is a rare diagnosis; its clinical and radiographic presentation can mimic that of acute appendicitis. We report the case of a two-year-old boy presenting with a one day history of lower abdominal pain and serial ultrasound examinations suspicious for atypical acute appendicitis. Operative findings revealed a necrotic and engorged appendix with a 720° clockwise torsion at its base. Final pathology was consistent with ischemic necrosis in the setting of lymphoid hyperplasia. A brief update on the current body of literature regarding pediatric torsion of the vermiform appendix is provided. Keywords: Appendicitis, Volvulus, Torsion

Incidence and predictive factors of isolated neonatal penile glanular torsion.

Science.gov (United States)

Sarkis, Pierrot E; Sadasivam, Muthurajan

2007-12-01

To determine the incidence of isolated neonatal penile glanular torsion, describe the basic characteristics, and explore the relationship between foreskin and glans torsion. A prospective survey was conducted of all male newborns admitted to nursery after delivery, or neonates less than 3 months presenting for circumcision. Cases with associated genital malformations were excluded. The incidence of isolated neonatal penile torsion was 27% (95% CI: 22.2%-31.84%), to the left in 99% of cases. In 3.5% of cases, the penis had an angle 20 degrees. Using Spearman's correlational coefficient, deviation of penile raphe from the midline at the foreskin tip had a better correlation with glans torsion than deviation of raphe at the coronal sulcus (0.727 vs 0.570; both significant at pscope of the study.

Torsional Properties of TiNi Shape Memory Alloy Tape for Rotary Actuator

Science.gov (United States)

Takeda, K.; Tobushi, H.; Mitsui, K.; Nishimura, Y.; Miyamoto, K.

2012-12-01

In order to develop novel shape memory actuators, the torsional deformation of a shape memory alloy (SMA) tape and the actuator models driven by the tape were investigated. The results obtained can be summarized as follows. In the SMA tape subjected to torsion, the martensitic transformation appears along both edges of the tape due to elongation of these elements and grows to the central part. The fatigue life in both the pulsating torsion and alternating torsion is expressed by the unified relationship of the dissipated work in each cycle. Based on an opening and closing door model and a solar-powered active blind model, the two-way rotary driving actuator with a small and simple mechanism can be developed by using torsion of the SMA tape.

Torsion of the Spermatic Cord: Is Bilateral Orchidopexy Really ...

African Journals Online (AJOL)

Aim: To evaluate the rationale for bilateral orchidopexy as treatment for unilateral torsion of the testis, by determining how frequently the contralateral testis shows an abnormal pathology in unilateral testicular torsion. Patients and Methods:This is a retrospective study using adult urology patients treated for both acute and ...

Plastic Behavior and Fracture of Aluminum and Copper in Torsion Tests

International Nuclear Information System (INIS)

Bressan, Jose Divo

2007-01-01

Present work investigates the plastic behavior, work hardening and the beginning of plastic instabilities, of cylindrical specimens deformed by high speed cold plastic torsion tests and at low speed tensile test. The tests were carried out in a laboratory torsion test equipment and an universal tensile test machine. The tensile tests were performed at room temperature in an universal testing machine at low strain rate of 0.034/s. Experimental torsion tests were carried out at constant angular speed that imposed a constant shear strain rate to the specimen. In the tests, the rotation speed were set to 62 rpm and 200 rpm which imposed high strain rates of about 2/s and 6.5/s respectively. The torsion tests performed at room temperature on annealed commercial pure copper and aluminum. Two types of torsion specimen for aluminum were used: solid and tubular. The solid aluminum specimen curves presented various points of maximum torque. The tubular copper specimens showed two points of maximum. Shear bands or shear strain localization at specimen were possibly the mechanism of maximum torque points formation. The work hardening coefficient n and the strain rate sensitivity parameter m were evaluated from the equivalent stress versus strain curve from tensile and torsion tests. The n-value remained constant whereas the m-value increased ten folds for aluminum specimens: from tensile test m= 0.027 and torsion test m= 0.27. However, the hardening curves were sigmoidal

5D Lovelock gravity: New exact solutions with torsion

Science.gov (United States)

Cvetković, B.; Simić, D.

2016-10-01

Five-dimensional Lovelock gravity is investigated in the first order formalism. A new class of exact solutions is constructed: the Bañados, Teitelboim, Zanelli black rings with and without torsion. We show that our solution with torsion exists in a different sector of the Lovelock gravity, as compared to the Lovelock Chern-Simons sector or the one investigated by Canfora et al. The conserved charges of the solutions are found using Nester's formula, and the results are confirmed by the canonical method. We show that the theory linearized around the background with torsion possesses two additional degrees of freedom with respect to general relativity.

Thermal characterization of phacoemulsification probes operated in axial and torsional modes.

Science.gov (United States)

Zacharias, Jaime

2015-01-01

To analyze temperature increases and identify potential sources of heat generated when sleeved and sleeveless phacoemulsification probes were operated in axial and torsional modes using the Infiniti Vision System with the Ozil torsional handpiece. Phacodynamics Laboratory, Pasteur Ophthalmic Clinic, Santiago, Chile. Experimental study. Two computer-controlled thermal transfer systems were developed to evaluate the contribution of internal metal stress and tip-to-sleeve friction on heat generation during phacoemulsification using axial and torsional ultrasound modalities. Both systems incorporated infrared thermal imaging and used a black-body film to accurately capture temperature measurements. Axial mode was consistently associated with greater temperature increases than torsional mode whether tips were operated with or without sleeves. In tests involving bare tips, axial mode and torsional mode peaked at 51.7°C and 34.2°C, respectively. In an example using sleeved tips in which a 30.0 g load was applied for 1 second, temperatures for axial mode reached 45°C and for torsional mode, 38°C. Friction between the sleeved probe and the incisional wall contributed more significantly to the temperature increase than internal metal stress regardless of the mode used. In all experiments, the temperature increase observed with axial mode was greater than that observed with torsional mode, even when conditions such as power or amplitude and flow rate were varied. Tip-to-sleeve friction was a more dominant source of phaco probe heating than internal metal stress. The temperature increase due to internal metal stress was greater with axial mode than with torsional mode. Dr. Zacharias received research funding from Alcon Laboratories, Inc., to conduct this study. He has no financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Asymmetric magnetoimpedance in amorphous microwires due to bias current: Effect of torsional stress

International Nuclear Information System (INIS)

Buznikov, N.A.; Antonov, A.S.; Granovsky, A.B.

2014-01-01

The influence of torsional stress on the asymmetric magnetoimpedance in a glass-coated negative magnetostrictive amorphous microwire due to bias current is studied theoretically. The longitudinal and off-diagonal impedance components are found assuming a simplified spatial distribution of the magnetoelastic anisotropy induced by the torsional stress. The asymmetry in the field dependence of the impedance components is attributed to the combination of the circular magnetic field produced by the bias current and a helical anisotropy induced by the torsional stress. The asymmetry in the magnetoimpedance and the low-field hysteresis are analyzed as a function of the bias current and torsional stress. It is shown that the application of torsional stress significantly changes the value of the bias current required to suppress the hysteresis effect. The results obtained may be useful for applications in magnetic-field and stress sensors. - Highlights: • Effects of torsional stress on magnetoimpedance in amorphous microwire are studied. • Asymmetry in magnetoimpedance is analyzed as a function of bias current and stress. • Torsional stress changes the anisotropy and effects on the microwire impedance. • Field-dependence of impedance is anhysteretic when bias current exceeds threshold value. • Threshold bias current can be tuned by the application of torsional stress

Asymmetric magnetoimpedance in amorphous microwires due to bias current: Effect of torsional stress

Energy Technology Data Exchange (ETDEWEB)

Buznikov, N.A., E-mail: n_buznikov@mail.ru [Scientific-Research Institute of Natural Gases and Gas Technologies – GAZPROM VNIIGAZ, Razvilka, Leninsky District, Moscow Region 142717 (Russian Federation); Antonov, A.S. [Institute for Theoretical and Applied Electrodynamics, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Granovsky, A.B. [Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation)

2014-04-15

The influence of torsional stress on the asymmetric magnetoimpedance in a glass-coated negative magnetostrictive amorphous microwire due to bias current is studied theoretically. The longitudinal and off-diagonal impedance components are found assuming a simplified spatial distribution of the magnetoelastic anisotropy induced by the torsional stress. The asymmetry in the field dependence of the impedance components is attributed to the combination of the circular magnetic field produced by the bias current and a helical anisotropy induced by the torsional stress. The asymmetry in the magnetoimpedance and the low-field hysteresis are analyzed as a function of the bias current and torsional stress. It is shown that the application of torsional stress significantly changes the value of the bias current required to suppress the hysteresis effect. The results obtained may be useful for applications in magnetic-field and stress sensors. - Highlights: • Effects of torsional stress on magnetoimpedance in amorphous microwire are studied. • Asymmetry in magnetoimpedance is analyzed as a function of bias current and stress. • Torsional stress changes the anisotropy and effects on the microwire impedance. • Field-dependence of impedance is anhysteretic when bias current exceeds threshold value. • Threshold bias current can be tuned by the application of torsional stress.

Bicavitary effusion secondary to liver lobe torsion in a dog

Directory of Open Access Journals (Sweden)

Khan Z

2016-04-01

Full Text Available Zaheda Khan,1 Kathryn Gates,2 Stephen A Simpson,31Emergency and Critical Care, Animal Specialty and Emergency Center, Los Angeles, CA, 2Emergency and Critical Care, Advanced Critical Care, Emergency and Specialty Services, Culver City, CA 3Emergency and Critical Care, Southern California Veterinary Specialty Hospital, Irvine, CA, USA Abstract: We described the diagnosis and successful treatment of pleural and peritoneal effusion secondary to liver lobe torsion in a dog. A 12-year-old female spayed Borzoi dog was referred for heart failure. Emergency room thoracic and abdominal ultrasound showed a large volume of pleural effusion with mild peritoneal effusion and an abdominal mass. Pleural fluid analysis classified the effusion as exudative. A complete ultrasound revealed mild peritoneal effusion and decreased blood flow to the right liver lobe. Other causes of bicavitary effusion were ruled out based on blood work, ultrasound, echocardiogram, and computed tomography. The patient was taken to surgery and diagnosed with caudate liver lobe torsion and had a liver lobectomy. At the 2-week postoperative recheck, the patient was doing well and there was complete resolution of the pleural effusion. Liver lobe torsion is a rare occurrence in dogs and can be difficult to diagnose. Clinical signs are nonspecific for liver lobe torsion and patients may present in respiratory distress with significant pleural fluid accumulation. When assessing patients with pleural and peritoneal effusion, liver lobe torsion should be considered as a differential diagnosis.Keywords: pleural effusion, peritoneal effusion, hepatic torsion

Gauge fields in a torsion field

International Nuclear Information System (INIS)

Rosu, Ion

2004-01-01

In this paper we analyse the motion and the field equations in a non-null curvature and torsion space. In this 4-n dimensional space, the connection coefficients are γ bc a = 1/2S bc a + 1/2T bc a, where S bc a is the symmetrical part and T bc a are the components of the torsion tensor. We will consider that all the fields depend on x = x α , α = 1,2,3,4 and do not depend on y = y k , k=1,2,...,n. The factor S bc a depends on the components of the metric tensor g αβ (x) and on the gauge fields A ν s 0 (x) and the components of the torsion depend only on the gauge fields A ν s 0 (x). We take into consideration the particular case for which the geodesic equations coincide with the motion equations in the presence of the gravitational and the gauge fields. In this case the field equations are Einstein equations in a 4-n dimensional space. We show that both the geodesic equations and the field equations can be obtained from a variational principle. (author)

Postoperative influences of the torsional phacoemulsification on foveal thickness and corneal edema

Directory of Open Access Journals (Sweden)

Lei Li

2014-05-01

Full Text Available AIM: To report the influences onfoveal thickness and corneal edema after torsional phacoemulsification.METHODS: Totally 52 patients(52 eyeswith age-related cataract were randomly assigned to phacoemulsification using torsional mode(26 eyesor conventional ultrasound mode(26 eyes. The foveal thickness examined by optical coherence tomography(OCTafter surgery at 1, 4 and 12wk and corneal edema was examined by slit lamp after surgery at 1d.RESULTS: The postoperative averagefoveal thickness datas of the two groups, comparing with corresponding preoperative datas, were significantly augmented at 1, 4 and 12wk(PPP>0.05. The effects of corneal edema in torsional group were slighter(PCONCLUSION: The postoperative influences onfoveal thickness and corneal edema with torsional mode are slighter than that with ultrasound mode, and the postoperative reactions with torsional mode are efficiently reduced.

Theoretical model for the mechanical behavior of prestressed beams under torsion

Directory of Open Access Journals (Sweden)

Sérgio M.R. Lopes

2014-12-01

Full Text Available In this article, a global theoretical model previously developed and validated by the authors for reinforced concrete beams under torsion is reviewed and corrected in order to predict the global behavior of beams under torsion with uniform longitudinal prestress. These corrections are based on the introduction of prestress factors and on the modification of the equilibrium equations in order to incorporate the contribution of the prestressing reinforcement. The theoretical results obtained with the new model are compared with some available results of prestressed concrete (PC beams under torsion found in the literature. The results obtained in this study validate the proposed computing procedure to predict the overall behavior of PC beams under torsion.

On the geometrization of electromagnetism by torsion

International Nuclear Information System (INIS)

Fonseca Neto, J.B. da.

1984-01-01

The possibility of electromagnetism geometrization using an four dimension Cartan geometry is investigated. The Lagrangian density which presents dual invariance for dyons electrodynamics formulated in term of two potentials is constructed. This theory by association of two potentials with track and with torsion pseudo-track and of the field with torsion covariant divergent is described. The minimum coupling of particle gravitational field of scalar and spinorial fields with dyon geometry theory by the minimum coupling of these fields with Cartan geometry was obtained. (author)

Additivity for parametrized topological Euler characteristic and Reidemeister torsion

OpenAIRE

Badzioch, Bernard; Dorabiala, Wojciech

2005-01-01

Dwyer, Weiss, and Williams have recently defined the notions of parametrized topological Euler characteristic and parametrized topological Reidemeister torsion which are invariants of bundles of compact topological manifolds. We show that these invariants satisfy additivity formulas paralleling the additive properties of the classical Euler characteristic and Reidemeister torsion of finite CW-complexes.

Tibial torsion in non-arthritic Indian adults: A computer tomography study of 100 limbs

Directory of Open Access Journals (Sweden)

Mullaji Arun

2008-01-01

Full Text Available Background: Knowledge of normal tibial torsion is mandatory during total knee replacement (TKR, deformity correction and fracture management of tibia. Different values of tibial torsion have been found in different races due to biological and mechanical factors. Value of normal tibial torsion in Indian limbs is not known, hence this study to determine the norm of tibial torsional value in normal Indian population. Materials and Methods: Computer tomography (CT scans were performed in 100 non-arthritic limbs of 50 Indian adults (42 males, eight females; age 26-40 years. Value of tibial torsion was measured using dorsal tangent to tibial condyles proximally and bimalleolar axis distally. Results: Normal tibial torsion was found to be 21.6 ± 7.6 (range 4.8 to 39.5 with none of the values in internal rotation. Right tibia was externally rotated by 2 degrees as compared to the left side ( P 0.029. No significant difference was found in male and female subjects. Value of tibial torsion was less than in Caucasian limbs, but was comparable to Japanese limbs when studies using similar measurement technique were compared. Conclusions: Indian limbs have less tibial torsion than Caucasian limbs but the value of tibial torsion is comparable to Japanese limbs.

High-pressure torsion of hafnium

International Nuclear Information System (INIS)

Edalati, Kaveh; Horita, Zenji; Mine, Yoji

2010-01-01

Pure Hf (99.99%) is processed by high-pressure torsion (HPT) under pressures of 4 and 30 GPa to form an ultrafine-grained structure with a gain size of ∼180 nm. X-ray diffraction analysis shows that, unlike Ti and Zr, no ω phase formation is detected after HPT processing even under a pressure of 30 GPa. A hydride formation is detected after straining at the pressure of 4 GPa. The hydride phase decomposes either by application of a higher pressure as 30 GPa or by unloading for prolong time after HPT processing. Microhardness, tensile and bending tests show that a high hardness (360 Hv) and an appreciable ductility (8%) as well as high tensile and bending strength (1.15 and 2.75 GPa, respectively) are achieved following the high-pressure torsion.

Effect of Torsional and Fatigue Preloading on HyFlex EDM Files.

Science.gov (United States)

Shen, Ya; Tra, Charles; Hieawy, Ahmed; Wang, Zhejun; Haapasalo, Markus

2018-04-01

The purpose of this study was to evaluate the effect of a low amount of torsional preloading on the fatigue life and different degrees of cyclic fatigue on torsional failure of HyFlex EDM (EDM; Coltene-Whaledent, Allstetten, Switzerland) and HyFlex CM (CM; Coltene-Whaledent) instruments. EDM and CM files were used. The fatigue resistance was examined in a 5-mm radius and 60° single curve, and the mean number of cycles to failure (N f ) was recorded. The torque and rotation angles at failure of the instruments were measured according to ISO 3630-1. New files were precycled to 0%, 50%, and 75% of the N f , and torsional tests were then performed. Other new files were preloaded at 5%, 15%, 25%, and 50% of the mean rotation angles before the fatigue test. The fracture surfaces of the fragments were examined under a scanning electron microscope. The fatigue resistance of EDM instruments was higher than that of CM instruments (P EDM at 15% preloading (P EDM files even with 50% torsional preloading was significantly higher than unused CM files (P EDM files. Moderate precycling (50%) of EDM files increased their torsional resistance. The fractographic patterns corresponded to the pattern defined by the last stage test. A low amount (15%) of torsional preloading reduced the fatigue resistance of EDM files, whereas even extensive (75%) precyclic fatigue was not detrimental to their torsional resistance. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Brans-Dicke theory in general space-time with torsion

International Nuclear Information System (INIS)

Kim, S.

1986-01-01

The Brans-Dicke theory in the general space-time endowed with torsion is investigated. Since the gradient of the scalar field as well as the intrinsic spin generate the torsion field, the interaction term of the spin-scalar field appears in the wave equation. The equations of motion are satisfied with the conservation laws

Mechanical Design of AM Fabricated Prismatic Rods under Torsion

Directory of Open Access Journals (Sweden)

Manzhirov Alexander V.

2017-01-01

Full Text Available We study the stress-strain state of viscoelastic prismatic rods fabricated or repaired by additive manufacturing technologies under torsion. An adequate description of the processes involved is given by methods of a new scientific field, mechanics of growing solids. Three main stages of the deformation process (before the beginning of growth, in the course of growth, and after the termination of growth are studied. Two versions of statement of two problems are given: (i given the torque, find the stresses, displacements, and torsion; (ii given the torsion, find the stresses, displacements, and torque. Solution methods using techniques of complex analysis are presented. The results can be used in mechanical and instrument engineering.

Topical Pain Relievers May Cause Burns

Science.gov (United States)

... joint pain relievers containing the active ingredients menthol, methyl salicylate and capsaicin. These cases were uncovered by FDA ... people who purchase these products, Tan notes. Menthol, methyl salicylate and capsaicin create sensations of local warmth or ...

Primary decomposition of torsion R[X]-modules

Directory of Open Access Journals (Sweden)

William A. Adkins

1994-01-01

Full Text Available This paper is concerned with studying hereditary properties of primary decompositions of torsion R[X]-modules M which are torsion free as R-modules. Specifically, if an R[X]-submodule of M is pure as an R-submodule, then the primary decomposition of M determines a primary decomposition of the submodule. This is a generalization of the classical fact from linear algebra that a diagonalizable linear transformation on a vector space restricts to a diagonalizable linear transformation of any invariant subspace. Additionally, primary decompositions are considered under direct sums and tensor product.

Rat disc torsional mechanics: effect of lumbar and caudal levels and axial compression load.

Science.gov (United States)

Espinoza Orías, Alejandro A; Malhotra, Neil R; Elliott, Dawn M

2009-03-01

Rat models with altered loading are used to study disc degeneration and mechano-transduction. Given the prominent role of mechanics in disc function and degeneration, it is critical to measure mechanical behavior to evaluate changes after model interventions. Axial compression mechanics of the rat disc are representative of the human disc when normalized by geometry, and differences between the lumbar and caudal disc have been quantified in axial compression. No study has quantified rat disc torsional mechanics. Compare the torsional mechanical behavior of rat lumbar and caudal discs, determine the contribution of combined axial load on torsional mechanics, and compare the torsional properties of rat discs to human lumbar discs. Cadaveric biomechanical study. Cyclic torsion without compressive load followed by cyclic torsion with a fixed compressive load was applied to rat lumbar and caudal disc levels. The apparent torsional modulus was higher in the lumbar region than in the caudal region: 0.081+/-0.026 (MPa/degrees, mean+/-SD) for lumbar axially loaded; 0.066+/-0.028 for caudal axially loaded; 0.091+/-0.033 for lumbar in pure torsion; and 0.056+/-0.035 for caudal in pure torsion. These values were similar to human disc properties reported in the literature ranging from 0.024 to 0.21 MPa/degrees. Use of the caudal disc as a model may be appropriate if the mechanical focus is within the linear region of the loading regime. These results provide support for use of this animal model in basic science studies with respect to torsional mechanics.

Dismal salvage of testicular torsion: A call to action! | Maranya ...

African Journals Online (AJOL)

... were not subjected to orchidopexy. There was no occurrence of torsion after orchidopexy. Conclusion: Testicular torsions were associated with low salvage rates. Increased public awareness coupled with clinician, parental, teacher, teenage and adult male education with respect to the consequences of acute scrotal pain ...

Torsion of the fallopian the mimicking appendicitis in a pregnant woman; Torsion de la trompa de Falopio en una mujer gestante simulando apendicitis

Energy Technology Data Exchange (ETDEWEB)

Tapia-Vine, M.; Pedrosa, I.; Escribano, N. [Hospital Clinico San Carlos (Spain)

2000-07-01

Isolated torsion of the fallopian tube is an uncommon entity. Given the difficulties involved in the preoperative diagnosis, the ultrasound findings characteristic of this anomaly are not widely known. We present a case of tubal torsion associated with a cyst, describing the ultrasound images in our case and those reported in the literature. (Author) 18 refs.

Torsion as a dynamic degree of freedom of quantum gravity

International Nuclear Information System (INIS)

Kim, Sang-Woo; Pak, D G

2008-01-01

The gauge approach to gravity based on the local Lorentz group with a general independent affine connection A μcd is developed. We consider SO(1, 3) gauge theory with a Lagrangian quadratic in curvature as a simple model of quantum gravity. The torsion is proposed to represent a dynamic degree of freedom of quantum gravity at scales above the Planckian energy. The Einstein-Hilbert theory is induced as an effective theory due to quantum corrections of torsion via generating a stable gravito-magnetic condensate. We conjecture that torsion possesses an intrinsic quantum nature and can be confined

Inferior oblique weakening surgery on ocular torsion in congenital superior oblique palsy

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Jinho Lee

2015-06-01

Full Text Available AIM:To investigate changes in fundus excyclotorsion after inferior oblique myectomy or myotomy.METHODS:The records of 21 patients undergoing strabismus surgery by a single surgeon between 2009 and 2012 were examined. Only patients who had undergone an inferior oblique myectomy or myotomy, with or without horizontal rectus muscle surgery, were evaluated. Digital fundus photographs were obtained, and the angle formed by a horizontal line passing through the optic disc center and a reference line connecting the foveola and optic disc center was measured. Associated clinical factors examined include age at the time of surgery, presence or absence of a head tilt, degree of preoperative vertical deviation, torsional angle, inferior oblique muscle overaction/superior oblique muscle underaction, and surgery laterality. Whether the procedure was performed alone or in combination with a horizontal rectus muscle surgery was also examined.RESULTS:Mean preoperative torsional angle was 12.0±6.4°, which decreased to 6.9±5.7° after surgery (P<0.001, paired t-test. Torsional angle also decreased from 15.1±7.0° to 6.2±4.3° in the myectomy group (P<0.001, paired t-test but there were no significant changes in the myotomy group (P=0.093, Wilcoxon signed rank test. Multivariable linear regression analysis showed that preoperative torsional angle, degree of inferior oblique overaction, and age at surgery independently and significantly affected postoperative torsional angle.CONCLUSION:Mean torsional angle decreased after inferior oblique myectomy. Degree of preoperative torsional angle, inferior oblique overaction, and age at surgery influence postoperative torsional angle.

Ionic polymer-metal composite torsional sensor: physics-based modeling and experimental validation

Science.gov (United States)

Aidi Sharif, Montassar; Lei, Hong; Khalid Al-Rubaiai, Mohammed; Tan, Xiaobo

2018-07-01

Ionic polymer-metal composites (IPMCs) have intrinsic sensing and actuation properties. Typical IPMC sensors are in the shape of beams and only respond to stimuli acting along beam-bending directions. Rod or tube-shaped IPMCs have been explored as omnidirectional bending actuators or sensors. In this paper, physics-based modeling is studied for a tubular IPMC sensor under pure torsional stimulus. The Poisson–Nernst–Planck model is used to describe the fundamental physics within the IPMC, where it is hypothesized that the anion concentration is coupled to the sum of shear strains induced by the torsional stimulus. Finite element simulation is conducted to solve for the torsional sensing response, where some of the key parameters are identified based on experimental measurements using an artificial neural network. Additional experimental results suggest that the proposed model is able to capture the torsional sensing dynamics for different amplitudes and rates of the torsional stimulus.

Torsional oscillations of the sun

International Nuclear Information System (INIS)

Snodgrass, H.B.; Howard, R.; National Solar Observatory, Tucson, AZ)

1985-01-01

The sun's differential rotation has a cyclic pattern of change that is tightly correlated with the sunspot, or magnetic activity, cycle. This pattern can be described as a torsional oscillation, in which the solar rotation is periodically sped up or slowed down in certain zones of latitude while elsewhere the rotation remains essentially steady. The zones of anomalous rotation move on the sun in wavelike fashion, keeping pace with and flanking the zones of magnetic activity. It is uncertain whether this torsional oscillation is a globally coherent ringing of the sun or whether it is a local pattern caused by and causing local changes in the magnetic fields. In either case, it may be an important link in the connection between the rotation and the cycle that is widely believed to exist but is not yet understood. 46 references

Torsional, tensile and structural properties of acrylonitrile–butadiene–styrene clay nanocomposites

International Nuclear Information System (INIS)

Singh, Priyanka; Ghosh, Anup K.

2014-01-01

Highlights: • Torsional behaviour of ABS and its nanocomposites is established. • Rheology is used as a tool to investigate the structure development of ABS nanocomposites. • Effect of nanoclay on resilience, toughness and ductility of ABS nanoclay is quantified. • ABS clay nanocomposites is correlated with rheological, mechanical and torsional behaviour. - Abstract: Torsional and tensile behaviour of acrylonitrile–butadiene–styrene (ABS)-clay nano-composites have been investigated and correlated with morphological and rheological characterisations. Nano-composites of ABS are prepared by melt compounding with different loading levels of nanoclay (Cloisite 30B) in a twin screw extruder and have been characterised in terms of torsional, axial and impact behaviour for their application in external orthotic devices. Tensile stress strain curve of nanocomposites are investigated to quantify resilience, toughness and ductility. Torque values of the nanocomposites are observed under torsion (10°–90°) and compared with that of neat ABS. Performance of ABS under torsional load improved by addition of nanoclay. Both modulus of elasticity and rigidity are found to improve in presence of nanoclay. State of dispersion in nano-composites is investigated using conventional methods such as transmission electron microscopy (TEM), X-ray diffraction (XRD), as well as by parallel plate rheometry. Addition of clay exhibits shear thinning effect and results in increase in storage modulus as well as complex viscosity of the nanocomposites. Zero shear viscosity rises tenfold with 1–2% addition of nanoclay, indicating the formation of structural network. It is found that state of dispersion of nanoclay governs the torsional and mechanical properties in ABS-clay nanocomposites

Isolated torsion of fallopian tube during pregnancy; report of two cases.

Science.gov (United States)

Yalcin, O T; Hassa, H; Zeytinoglu, S; Isiksoy, S

1997-08-01

Isolated torsion of fallopian tube is very uncommon during pregnancy. Predisposing factors for torsion are hydrosalpinx, prior tubal operation, pelvic congestion, ovarian and paraovarian masses and trauma. Although the most important clinical symptom is abdominal pain in lower quadrants, the diagnosis is usually established during the operation performed for acute abdomen and salpingectomy is almost always necessary. Two cases of torsion of fallopian tube during pregnancy, one with hydrosalpinx, the other with paratubal cyst are presented and symptoms and predisposing factors are discussed.

TORSION TESTIS : ROLE OF COLOR DOPPLER : A STUDY OF 50 CASES

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Anand

2015-09-01

Full Text Available BACKGROUND: T orsion testis is one of the catast r ophic conditions in children and young a d u lts. Traditionally the diagnosis was made clinical presentation and suspicion. Critical decision making is essential to save the testis . OBJECTIVE: To study the usefu lness and efficacy of Doppler ultrasound in correctly diagnosing acute scrotal conditions in children and young adults to save the testis and to avoid negative explorations. METHODS: Over a period of two years 50 patients with acute scrotum were admitted i n general surgery department who underwent Doppler ultrasound scrotum and its efficacy in correctly diagnosing the pathology was analysed. RESULTS: 50 patients with age group <25 years were included in study. Scrotal pain was the most frequent presenting s ymptom of acute scrotum (98% followed by Swelling of the hemiscrolum on the involved side present in 86% of the patients. Doppler ultrasound showed torsion of testis in 18 patients. On Scrotal exploration, torsion of spermatic cord was confirmed in 16 pat ients, one patient had torsion of appendix of testis and the other had Epididymo - orchitis. Thus the sensitivity and specificity of Doppler ultrasonography for testicular torsion was 86.9% and 92.6% respectively. 2 patients with equivocal Doppler findings, but strong clinical suspicion of testicular torsion were explored, and testis was found to be torsed in both two patients. Doppler ultrasonography showed Epididymo - orchitis in 22 patients, torsion of testicular appendage in 2 patients, Idiopathic scrotal edema in one, and in 5 pts no significant pathology found. All twenty patients of epididymo - orchitis, two patients of torsion of testicular appendage, and one patient of idiopathic scrotal edema were managed conservatively. At three weeks follow up, all th e patients were free of symptoms. The sensitivity and specificity of Doppler ultrasonography for epididymo - orchitis was 95% and 100% respectively. CONCLUSIONS: color

Intravitreal Phacoemulsification Using Torsional Handpiece for Retained Lens Fragments

OpenAIRE

Kumar, Vinod; Takkar, Brijesh

2016-01-01

Purpose: To evaluate the results of intravitreal phacoemulsification with torsional hand piece in eyes with posteriorly dislocated lens fragments. Methods: In this prospective, interventional case series, 15 eyes with retained lens fragments following phacoemulsification were included. All patients underwent standard three-port pars plana vitrectomy and intravitreal phacoemulsification using sleeveless, torsional hand piece (OZiL™, Alcon's Infiniti Vision System). Patients were followed up...

Model of Structural Fragmentation Induced by High Pressure Torsion

Czech Academy of Sciences Publication Activity Database

Kratochvíl, J.; Kružík, Martin; Sedláček, R.

2010-01-01

Roč. 25, č. 1 (2010), s. 88-98 ISSN 1606-5131 Institutional research plan: CEZ:AV0Z10750506 Keywords : High-pressure torsion * intergranular glide * homogeneous deformation mode Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.649, year: 2010 http://library.utia.cas.cz/separaty/2010/MTR/kruzik-model of structural fragmentation induced by high pressure torsion.pdf

EOS analysis of lower extremity segmental torsion in children and young adults.

Science.gov (United States)

Gaumétou, E; Quijano, S; Ilharreborde, B; Presedo, A; Thoreux, P; Mazda, K; Skalli, W

2014-02-01

Lower limb torsion varies substantially among healthy children during growth. Values reported in the literature to date have been obtained using semi-quantitative clinical or 2D measurement methods. Quantitative 3D measurement would help determine the physiological range of lower limb torsion. Low-dose stereoradiography with 3D reconstruction provides a good alternative. Its use increases in pediatrics because of radiation minimization. Previous studies have shown accurate and reproducible results of lower limbs reconstruction in adults and children but the torsional parameters haven't been measured yet. The present study reports the values of lower limb segmental torsion and its course during growth in a cohort of healthy children and young adults using the EOS low-dose biplanar X-ray. EOS 3D reconstruction is an accurate and reproducible method to measure the torsional parameters in children. Femoral torsion (FT) and tibial torsion (TT) were studied on 114 volunteers (228 lower limbs) from 6 to 30 years of age divided by age into 5 groups. The EOS™ acquisitions were obtained in subjects standing with their feet offset. Mean FT decreased during growth, passing from 21.6° to 18°, whereas mean TT increased from 26.8° to 34.7°. There was a statistically significant difference between the 2 extreme age groups, but no difference was found between any other age groups. The ICC for intra-observer reproducibility was 0.96 and 0.95 for FT and TT for the first operator, and 0.79 and 0.83 for the second operator respectively. The ICC for inter-observer reproducibility was 0.84 and 0.82 respectively. The course of lower limb segmental torsion observed was consistent with literature reports based upon clinical and 2D measurements. 3D reconstruction of EOS low-dose biplanar imaging appears to be a safe and reliable tool for lower limbs measurements, especially for investigating lower limb segmental torsion in children and adults. Level IV. Copyright © 2013. Published by

Outcomes of Surgery for Posterior Polar Cataract Using Torsional Ultrasound

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Selçuk Sızmaz

2013-10-01

Full Text Available Purpose: The aim of this study is to report outcomes of surgery for posterior polar cataract using torsional ultrasound. Material and Method: Medical records of 26 eyes of 21 consecutive patients with posterior polar cataract who had cataract surgery using the torsional phacoemulsification were evaluated retrospectively. The surgical procedure used, phacoemulsification parameters, intraoperative complications, and postoperative visual outcome were recorded. Results: Of the 26 eyes, 24 (92.3% had small to medium posterior polar opacity. Two eyes had large opacity. All surgeries were performed using the torsional handpiece. Posterior capsule rupture occurred in 4 (15.3% eyes. The mean visual acuity improved significantly after surgery (p<0.001. The postoperative visual acuity was worse than 20/20 in 5 eyes. The cause of the low acuity was amblyopia. Discussion: Successful surgical results and good visual outcome can be achieved with phacoemulsification using the torsional handpiece. (Turk J Ophthalmol 2013; 43: 345-7

A Rare Cause of Scrotal Mass in a Newborn: Antenatal Intravaginal Testicular Torsion

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Ahmet Ali Tuncer

2018-04-01

Full Text Available Intravaginal testicular torsion is a very rare pathology in the neonatal period. However, it is the most common type of torsion in puberty. In this article, we present a male patient with testicular hyperemia and a mass in the testis. Ultrasonography revealed intravaginal testicular torsion and absence of testicular blood flow. This paper aims to draw attention to the importance of neonatal examination for the presence of testicular torsion which is a rare pathology in newborns with scrotal colour change or presence of an abnormal mass.

Numerical Analysis on Variation of Dynamic Response of Girder Bridges with Torsional Reinforcement Panels

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Kang Jae-Yoon

2015-01-01

Full Text Available The dynamic flexural behaviour of the railway bridge is influenced by its torsional behaviour. Especially, in the case of girder railway bridges, the dynamic response tends to amplify when the natural frequency in flexure (1st vibration mode is close to that in torsion (2nd vibration mode. In order to prevent such situation, it is necessary to adopt a flexural-to-torsional natural frequency ratio larger than 120%. This study proposes a solution shifting the natural frequency in torsion to high frequency range and restraining torsion by installing concrete panels on the bottom flange of the girder so as to prevent the superposition of the responses in the girder bridge. The applicability of this solution is examined by finite element analysis of the shift of the torsional natural frequency and change in the dynamic response according to the installation of the concrete panels. The analytical results for a 30 m-span girder railway bridge indicate that installing the concrete panels increases the natural frequency in torsion by restraining the torsional behaviour and reduces also the overall dynamic response. It is seen that the installation of 100 mm-thick concrete panels along a section of 4 m at both extremities of the girder can reduce the dynamic response by more than 30%.

A Patient Presenting with Concurrent Testis Torsion and Epididymal Leiomyoma

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E. Arpali

2013-01-01

Full Text Available Leiomyomas are the second most common tumors of epididymis. Patients with leiomyomas are sometimes misdiagnosed with testicular tumors. A Case of a patient with a scrotal mass presenting with testicular torsion is reported. Concurrent occurrence of testicular torsion and epididymal leiomyoma is an extremely rare condition.

Substructural evolution during cyclic torsion of drawn low carbon steel bars

International Nuclear Information System (INIS)

Correa, E.C.S.; Aguilar, M.T.P.; Monteiro, W.A.; Cetlin, P.R.

2006-01-01

Strain softening effects have been previously observed in drawn low carbon steel bars as a result of cyclic torsion experiments. In this paper, the substructural aspects related to the phenomenon have been investigated. Single pass drawn bars were subjected to a quarter, to a half, to a full torsion cycle and to 10 such cycles. Transmission electron microscopy revealed the development of extended microbands crossing the former dislocation arrangement of the drawn metal, which evolves to a rectangular shaped subgrains structure as torsion deformation is conducted

Generalised discrete torsion and mirror symmetry for G2 manifolds

International Nuclear Information System (INIS)

Gaberdiel, Matthias R.; Kaste, Peter

2004-01-01

A generalisation of discrete torsion is introduced in which different discrete torsion phases are considered for the different fixed points or twist fields of a twisted sector. The constraints that arise from modular invariance are analysed carefully. As an application we show how all the different resolutions of the T 7 /Z 2 3 orbifold of Joyce have an interpretation in terms of such generalised discrete torsion orbifolds. Furthermore, we show that these manifolds are pairwise identified under G 2 mirror symmetry. From a conformal field theory point of view, this mirror symmetry arises from an automorphism of the extended chiral algebra of the G 2 compactification. (author)

Torsion of the greater omentum: A rare preoperative diagnosis

International Nuclear Information System (INIS)

Tandon, Ankit Anil; Lim, Kian Soon

2010-01-01

Torsion of the greater omentum is a rare acute abdominal condition that is seldom diagnosed preoperatively. We report the characteristic computed tomography (CT) scan findings and the clinical implications of this unusual diagnosis in a 41-year-old man, who also had longstanding right inguinal hernia. Awareness of omental torsion as a differential diagnosis in the acute abdomen setting is necessary for correct patient management

Development of a method for measuring femoral torsion using real-time ultrasound

International Nuclear Information System (INIS)

Hafiz, Eliza; Hiller, Claire E; Nightingale, E Jean; Eisenhuth, John P; Refshauge, Kathryn M; Nicholson, Leslie L; Clarke, Jillian L; Grimaldi, Alison

2014-01-01

Excessive femoral torsion has been associated with various musculoskeletal and neurological problems. To explore this relationship, it is essential to be able to measure femoral torsion in the clinic accurately. Computerized tomography (CT) and magnetic resonance imaging (MRI) are thought to provide the most accurate measurements but CT involves significant radiation exposure and MRI is expensive. The aim of this study was to design a method for measuring femoral torsion in the clinic, and to determine the reliability of this method. Details of design process, including construction of a jig, the protocol developed and the reliability of the method are presented. The protocol developed used ultrasound to image a ridge on the greater trochanter, and a customized jig placed on the femoral condyles as reference points. An inclinometer attached to the customized jig allowed quantification of the degree of femoral torsion. Measurements taken with this protocol had excellent intra- and inter-rater reliability (ICC 2,1  = 0.98 and 0.97, respectively). This method of measuring femoral torsion also permitted measurement of femoral torsion with a high degree of accuracy. This method is applicable to the research setting and, with minor adjustments, will be applicable to the clinical setting. (paper)

On unified field theories, dynamical torsion and geometrical models: II

International Nuclear Information System (INIS)

Cirilo-Lombardo, D.J.

2011-01-01

We analyze in this letter the same space-time structure as that presented in our previous reference (Part. Nucl, Lett. 2010. V.7, No.5. P.299-307), but relaxing now the condition a priori of the existence of a potential for the torsion. We show through exact cosmological solutions from this model, where the geometry is Euclidean RxO 3 ∼ RxSU(2), the relation between the space-time geometry and the structure of the gauge group. Precisely this relation is directly connected with the relation of the spin and torsion fields. The solution of this model is explicitly compared with our previous ones and we find that: i) the torsion is not identified directly with the Yang-Mills type strength field, ii) there exists a compatibility condition connected with the identification of the gauge group with the geometric structure of the space-time: this fact leads to the identification between derivatives of the scale factor a with the components of the torsion in order to allow the Hosoya-Ogura ansatz (namely, the alignment of the isospin with the frame geometry of the space-time), and iii) of two possible structures of the torsion the 'tratorial' form (the only one studied here) forbid wormhole configurations, leading only to cosmological instanton space-time in eternal expansion

Torsion as a dark matter candidate from the Higgs portal

Science.gov (United States)

Belyaev, Alexander S.; Thomas, Marc C.; Shapiro, Ilya L.

2017-05-01

Torsion is a metric-independent component of gravitation, which may provide a more general geometry than the one taking place within general relativity. On the other hand, torsion could lead to interesting phenomenology in both particle physics and cosmology. In the present work it is shown that a torsion field interacting with the SM Higgs doublet and having a negligible coupling to standard model (SM) fermions is protected from decaying by a Z2 symmetry, and therefore becomes a promising dark matter (DM) candidate. This model provides a good motivation for Higgs portal vector DM scenario. We evaluate the DM relic density and explore direct DM detection and collider constraints on this model to understand its consistency with experimental data and establish the most up-to-date limits on its parameter space. We have found in the model when the Higgs boson is only partly responsible for the generation of torsion mass, there is a region of parameter space where torsion contributes 100% to the DM budget of the Universe. Furthermore, we present the first results on the potential of the LHC to probe the parameter space of minimal scenario with Higgs portal vector DM using mono-jet searches and have found that LHC at high luminosity will be sensitive to the substantial part of model parameter space which cannot be probed by other experiments.

Crack path in aeronautical titanium alloy under ultrasonic torsion loading

Directory of Open Access Journals (Sweden)

A. Nikitin

2016-01-01

Full Text Available This paper discusses features of fatigue crack initiation and growth in aeronautical VT3-1 titanium alloy under pure torsion loading in gigacycle regime. Two materials: extruded and forged VT3-1 titanium alloys were studied. Torsion fatigue tests were performed up to fatigue life of 109 cycles. The results of the torsion tests were compared with previously obtained results under fully reversed axial loading on the same alloys. It has been shown that independently on production process as surface as well subsurface crack initiation may appear under ultrasonic torsion loading despite the maximum stress amplitude located at the specimen surface. In the case of surface crack initiation, a scenario of crack initiation and growth is similar to HCF regime except an additional possibility for internal crack branching. In the case of subsurface crack, the initiation site is located below the specimen surface (about 200 μm and is not clearly related to any material flaw. Internal crack initiation is produced by shear stress in maximum shear plane and early crack growth is in Mode II. Crack branching is limited in the case of internal crack initiation compared to surface one. A typical ‘fish-eye’ crack can be observed at the torsion fracture surface, but mechanism of crack initiation seems not to be the same than under axial fatigue loading.

Experimental evaluation of torsional fatigue strength of welded bellows and application to design of fusion device

International Nuclear Information System (INIS)

Takatsu, Hideyuki; Yamamoto, Masahiro; Shimizu, Masatsugu; Suzuki, Kazuo; Sonobe, Tadashi; Hayashi, Yuzo; Mizuno, Gen-ichiro.

1984-01-01

Torsional fatigue strength of the welded bellows was evaluated experimentally, aiming the application to a port of a fusion device. The welded bellows revealed elastic torsional buckling and spiral distorsion even under a small angle of torsion. Twisting load never leads the welded bellows to fracture easily so far as the angle of torsion is not excessively large, and the welded bellows has the torsional fatigue strength much larger than that expected so far. Two formulae were proposed to evaluate the stress of the welded bellows under the forced angle of torsion; shearing stress evaluation formula in the case that torsional buckling does not occur and the axial bending stress evaluation formula in the case that torsional buckling occurs. And the results of the torsional fatigue experiments showed that the former is reasonably conservative and simulates the actual behavior of the welded bellows better than the latter in the high cycle fatigue region and vice versa in the low cycle fatigue region from the viewpoint of the mechanical design. The present evaluation method of the torsional fatigue strength was applied to the welded bellows for the port of the JT-60 vacuum vessel and its structural integrity was confirmed under the design load condition. (author)

Boundary integral method for torsion of composite shafts

International Nuclear Information System (INIS)

Chou, S.I.; Mohr, J.A.

1987-01-01

The Saint-Venant torsion problem for homogeneous shafts with simply or multiply-connected regions has received a great deal of attention in the past. However, because of the mathematical difficulties inherent in the problem, very few problems of torsion of shafts with composite cross sections have been solved analytically. Muskhelishvili (1963) studied the torsion problem for shafts with cross sections having several solid inclusions surrounded by an elastic material. The problem of a circular shaft reinforced by a non-concentric round inclusion, a rectangular shaft composed of two rectangular parts made of different materials were solved. In this paper, a boundary integral equation method, which can be used to solve problems more complex than those considered by Katsikadelis et. al., is developed. Square shaft with two dissimilar rectangular parts, square shaft with a square inclusion are solved and the results compared with those given in the reference cited above. Finally, a square shaft composed of two rectangular parts with circular inclusion is solved. (orig./GL)

Dynamic and Progressive Control of DNA Origami Conformation by Modulating DNA Helicity with Chemical Adducts.

Science.gov (United States)

Chen, Haorong; Zhang, Hanyu; Pan, Jing; Cha, Tae-Gon; Li, Shiming; Andréasson, Joakim; Choi, Jong Hyun

2016-05-24

DNA origami has received enormous attention for its ability to program complex nanostructures with a few nanometer precision. Dynamic origami structures that change conformation in response to environmental cues or external signals hold great promises in sensing and actuation at the nanoscale. The reconfiguration mechanism of existing dynamic origami structures is mostly limited to single-stranded hinges and relies almost exclusively on DNA hybridization or strand displacement. Here, we show an alternative approach by demonstrating on-demand conformation changes with DNA-binding molecules, which intercalate between base pairs and unwind DNA double helices. The unwinding effect modulates the helicity mismatch in DNA origami, which significantly influences the internal stress and the global conformation of the origami structure. We demonstrate the switching of a polymerized origami nanoribbon between different twisting states and a well-constrained torsional deformation in a monomeric origami shaft. The structural transformation is shown to be reversible, and binding isotherms confirm the reconfiguration mechanism. This approach provides a rapid and reversible means to change DNA origami conformation, which can be used for dynamic and progressive control at the nanoscale.

Numerical Investigation of Damping of Torsional Beam Vibrations by Viscous Bimoments

DEFF Research Database (Denmark)

Hoffmeyer, David; Høgsberg, Jan Becker

2017-01-01

Damping of torsional beam vibrations of slender beam–structures with thin–walled cross–sections is investigated. Analytical results from solving the differential equation governing torsion with viscous bimoments imposed at the boundary, are compared with a numerical approach with three...

The accuracy of serum interleukin-6 and tumour necrosis factor as markers for ovarian torsion.

Science.gov (United States)

Cohen, S B; Wattiez, A; Stockheim, D; Seidman, D S; Lidor, A L; Mashiach, S; Goldenberg, M

2001-10-01

The aim of this study was to investigate a possible role for interleukin-6 (IL-6) and tumour necrosis factor (TNF-alpha) as pre-operative markers for the diagnosis of ovarian torsion. Twenty consecutive patients admitted to the gynaecological emergency room with suspected clinical diagnosis of ovarian torsion were prospectively assigned to the study. Blood samples were drawn pre-operatively and examined for serum concentrations of IL-6 and TNF-alpha. Surgeons were blinded to laboratory results prior to laparoscopy. The pre-operative diagnosis of ovarian torsion was confirmed during an urgent diagnostic laparoscopy in 8 (40%) patients. The surgical diagnosis among the remaining 12 patients was a large ovarian cyst not in torsion. In six out of eight (75.0%) patients with ovarian torsion serum IL-6 concentrations were elevated. None of the 12 patients without torsion had elevated serum IL-6 concentrations. This difference was statistically significant (P < 0.001). There was no significant difference in the proportion of women with elevated serum TNF-alpha concentrations, two of eight (25.0%) patients with torsion and four of 12 (33.3%) control cases. Elevated serum IL-6 concentrations, but not serum TNF-alpha concentrations, were significantly associated with the occurrence of ovarian torsion. In patients with vague clinical signs of ovarian torsion, serum IL-6 might help to distinguish which patients should undergo diagnostic laparoscopy.

Elastic torsional buckling of thin-walled composite cylinders

Science.gov (United States)

Marlowe, D. E.; Sushinsky, G. F.; Dexter, H. B.

1974-01-01

The elastic torsional buckling strength has been determined experimentally for thin-walled cylinders fabricated with glass/epoxy, boron/epoxy, and graphite/epoxy composite materials and composite-reinforced aluminum and titanium. Cylinders have been tested with several unidirectional-ply orientations and several cross-ply layups. Specimens were designed with diameter-to-thickness ratios of approximately 150 and 300 and in two lengths of 10 in. and 20 in. The results of these tests were compared with the buckling strengths predicted by the torsional buckling analysis of Chao.

Quantum gravity effect in torsion driven inflation and CP violation

Energy Technology Data Exchange (ETDEWEB)

Choudhury, Sayantan [Department of Theoretical Physics, Tata Institute of Fundamental Research,Colaba, 1, Homi Bhabha Road, Mumbai 400005 (India); Pal, Barun Kumar [Inter-University Centre for Astronomy and Astrophysics,Ganeshkhind, Pune 411007 (India); Netaji Nagar College for Women,Regent Estate, Kolkata 700092 (India); Basu, Banasri; Bandyopadhyay, Pratul [Physics and Applied Mathematics Unit, Indian Statistical Institute,203 B.T. Road, Kolkata 700 108 (India)

2015-10-28

We have derived an effective potential for inflationary scenario from torsion and quantum gravity correction in terms of the scalar field hidden in torsion. A strict bound on the CP violating θ parameter, O(10{sup −10})<θ

Quantum gravity effect in torsion driven inflation and CP violation

International Nuclear Information System (INIS)

Choudhury, Sayantan; Pal, Barun Kumar; Basu, Banasri; Bandyopadhyay, Pratul

2015-01-01

We have derived an effective potential for inflationary scenario from torsion and quantum gravity correction in terms of the scalar field hidden in torsion. A strict bound on the CP violating θ parameter, O(10"−"1"0)<θ< O(10"−"9) has been obtained, using Planck+WMAP9 best fit cosmological parameters.

A 55-Year-Old Man with Right Testicular Pain: Too Old for Torsion?

Science.gov (United States)

Tang, Yu Ho; Yeung, Victor Hip Wo; Chu, Peggy Sau Kwan; Man, Chi Wai

2017-02-01

Testicular torsion is predominantly a disease of adolescence, but age itself should not be an exclusion criterion for the diagnosis. A lack of suspicion for testicular torsion in older patients may result in a missed or delayed diagnosis which jeopardizes the chance of testicular salvage. In this article, we report a case of testicular torsion in a 55-year-old Chinese man.

Unilateral testicular torsion following ejaculation by manual sexual stimulation in an adolescent: A case report

Directory of Open Access Journals (Sweden)

Omer Faruk Yagli

2018-05-01

Full Text Available Testicular torsion is one of the most common causes of acute scrotum in children and adolescents. The bell-clapper deformity, which detected in 12% of males, is the most important reason that leads to testicular torsion. In our case, a 14 years old male admitted to our clinic due to testicular torsion developed after ejaculation with manual sexual stimulation of the penis. The most important criteria in determining the loss of testis is the degree and duration of torsion. Here, we discussed the rare cause of testicular torsion along with diagnostic and therapeutic characteristics.

Anharmonic longitudinal motion of bases and dynamics of nonlinear excitation in DNA.

Science.gov (United States)

Di Garbo, Angelo

2016-01-01

The dynamics of the transcription bubble in DNA is studied by using a nonlinear model in which torsional and longitudinal conformations of the biomolecule are coupled. In the absence of forcing and dissipation the torsional dynamics is described by a perturbed kink of the Sine-Gordon DNA model, while the longitudinal conformational energy propagate as phonons. It was found that for random initial conditions of the longitudinal conformational field the presence of the kink promotes the creation of phonons propagating along the chain axis. Moreover, the presence of forcing, describing the active role of RNA polymerase, determines in agreement to the experimental data a modulation of the velocity of the transcription bubble. Lastly, it was shown that the presence of dissipation impacts the dynamic of the phonon by reducing the amplitude of the corresponding conformational field. On the contrary, dissipation and forcing modulate the velocity of the transcription bubble alone.

Topological invariants and the dynamics of an axial vector torsion field

International Nuclear Information System (INIS)

Drechsler, W.

1983-01-01

A generalized throry of gravitation is discussed which is based on a Riemann-Cartan space-time, U 4 , with an axial vector torsion field. Besides Einstein's equations determining the metric of the U 4 a system of nonlinear field equations is established coupling an axial vector source current to the axial vector torsion field. The properties of the solutions of these equations are discussed assuming a London-type condition relating the axial current and torsion field. To characterize the solutions use is made of the Euler and Pontrjagin forms and the associated quadratic curvature invariants for the U 4 space-time. It is found that there exists for a Riemann-Cartan space-time a relation between the zeros of the axial vector torsion field and the singularities of the Pontrjagin invariant, which is analogous to the well-known Hopf relation between the zeros of vector fields and the Euler characteristic. (author)

Constraints on torsion from the bosonic sector of Lorentz violation and magnetogenesis data

International Nuclear Information System (INIS)

Garcia de Andrade, L.C.

2011-01-01

A. Kostelecky et al. [Phys. Rev. Lett. 100 (2008) 111102], have shown that there is an exceptional sensitivity of spacetime torsion components by coupling it to fermions and constraining it to Lorentz violation. They obtain new constraints on torsion components down to the level of 10 -31 GeV. Yet more recently, L.C. Garcia de Andrade [Phys. Lett. B 468 (2011) 28] has shown that the photon sector of Lorentz violation (LV) Lagrangian leads to linear non-standard Maxwell equations where the magnetic field decays slower giving rise to a seed for galactic dynamos. In this paper bounds are placed on torsion based on the magnetogenesis or the origin of magnetic fields in the universe. On a coherence scale of 10 kpc, galactic magnetic fields of the order of some μG yield a torsion primordial field of the order of K 0 ∼10 -48 GeV. Just to give an idea of how tiny it is we mention that torsion limit in the Early universe yield K 0 ∼10 -31 GeV had been obtained by V. de Sabbata and C. Sivaram. Good limits were also obtained by B.R. Heckel et al. [Phys. Rev. D 78 (2008) 092006]. In our case the advantage from astro-particle physics point of view, is that a very small seed torsion field is enough to seed galactic dynamo. C. Sivaram limit is obtained from a massive photon electrodynamics [L.C. Garcia de Andrade, C. Sivaram, Ap. Space Sci. 209 (1993) 109] where a gauge invariant electrodynamics is used. Dynamo stars data are able to raise this value of torsion up to 10 -34 GeV at magnetar atmosphere. From these estimates one notices that they coincide with the ones obtained by A. Kostelecky et al., the difference being basically in the method. The ones here were obtained from magnetogenesis data while theirs were obtained from the Earth laboratory data from polarised electrons. Besides here one used the torsion derivatives while A. Kostelecky et al. uses the constant axial torsion tensor. Another fundamental distinction is that we use bosonic sector of the Lagrangian while

Intraoperative performance and postoperative outcome comparison of longitudinal, torsional, and transversal phacoemulsification machines.

Science.gov (United States)

Christakis, Panos G; Braga-Mele, Rosa M

2012-02-01

To compare the intraoperative performance and postoperative outcomes of 3 phacoemulsification machines that use different modes. Kensington Eye Institute, Toronto, Ontario, Canada. Comparative case series. This chart and video review comprised consecutive eligible patients who had phacoemulsification by the same surgeon using a Whitestar Signature Ellips-FX (transversal), Infiniti-Ozil-IP (torsional), or Stellaris (longitudinal) machine. The review included 98 patients. Baseline characteristics in the groups were similar; the mean nuclear sclerosis grade was 2.0 ± 0.8. There were no significant intraoperative complications. The torsional machine averaged less phacoemulsification needle time (83 ± 33 seconds) than the transversal (99 ± 40 seconds; P=.21) or longitudinal (110 ± 45 seconds; P=.02) machines; the difference was accentuated in cases with high-grade nuclear sclerosis. The torsional machine had less chatter and better followability than the transversal or longitudinal machines (P<.001). The torsional and longitudinal machines had better anterior chamber stability than the transversal machine (P<.001). Postoperatively, the torsional machine yielded less central corneal edema than the transversal (P<.001) and longitudinal (P=.04) machines, corresponding to a smaller increase in mean corneal thickness (torsional 5%, transversal 10%, longitudinal 12%; P=.04). Also, the torsional machine had better 1-day postoperative visual acuities (P<.001). All 3 phacoemulsification machines were effective with no significant intraoperative complications. The torsional machine outperformed the transversal and longitudinal machines, with a lower mean needle time, less chatter, and improved followability. This corresponded to less corneal edema 1 day postoperatively and better visual acuity. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Unusual cause of acute abdomen in a child--torsion of greater omentum: report of two cases.

Science.gov (United States)

Pogorelić, Zenon; Katić, Josip; Gudelj, Karla; Mrklić, Ivana; Vilović, Katarina; Perko, Zdravko

2015-08-01

Torsion of the omentum is twisting along its long axis and a rare cause of acute abdomen. Depending on associated conditions, it is classified as primary and secondary. It may mimic different pathologies presenting as acute abdomen, most common of them being acute appendicitis. Current choice for management of omental torsion is laparoscopic surgery. We present two cases of omental torsion of two boys who presented with abdominal pain, nausea and vomiting and underwent emergency laparoscopy. Omental torsion is very rare, and its diagnosis is usually made only after surgery. At laparoscopy, omental torsion is suspected when the appendix is normal and the symptoms and findings of torsion are present. Laparoscopy is a safe and effective approach for the diagnosis and management of omental torsion, with the advantages of reduced postoperative pain and hospital stay. © The Author(s) 2015.

Torsional actuation with extension-torsion composite coupling and a magnetostrictive actuator

Science.gov (United States)

Bothwell, Christopher M.; Chandra, Ramesh; Chopra, Inderjit

1995-04-01

An analytical-experimental study of using magnetostrictive actuators in conjunction with an extension-torsion coupled composite tube to actuate a rotor blade trailing-edge flap to actively control helicopter vibration is presented. Thin walled beam analysis based on Vlasov theory was used to predict the induced twist and extension in a composite tube with magnetostrictive actuation. The study achieved good correlation between theory and experiment. The Kevlar-epoxy systems showed good correlation between measured and predicted twist values.

Flexural-torsional buckling analysis of angle-bar stiffened plates

Energy Technology Data Exchange (ETDEWEB)

Ahmad, Rahbar Ranji [Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

2015-09-15

The interaction of flexural-torsional buckling modes is critical for stiffened plates with asymmetric stiffeners. However, this interaction is ignored in all design rules because it is complex to characterize. In the literature, the presence of an attached plate is ignored, and stiffened plate is treated as an ordinary asymmetric beam. In the flexural buckling mode, stiffener and the attached plate buckle together; in the torsional buckling mode, the attached plate cannot freely rotate with stiffener. Basic equations of the flexural-torsional buckling modes are deduced based on hybrid beam concept and a new strain distribution assumption for sideway bending of stiffeners. Elastic buckling stresses of different angle-bar stiffened plates are calculated and compared with those generated by the Finite element method (FEM) and those available in the literature. The present method has better agreements with FEM.

Running coupling in electroweak interactions of leptons from f(R)-gravity with torsion

International Nuclear Information System (INIS)

Capozziello, Salvatore; De Laurentis, Mariafelicia; Fabbri, Luca; Vignolo, Stefano

2012-01-01

The f(R)-gravitational theory with torsion is considered for one family of leptons; it is found that the torsion tensor gives rise to interactions having the structure of the weak forces, while the intrinsic non-linearity of the f(R) function provides an energy-dependent coupling: in this way, torsional f(R) gravity naturally generates both structure and strength of the electroweak interactions among leptons. This implies that the weak interactions among the lepton fields could be addressed as a geometric effect due to the interactions among spinors induced by the presence of torsion in the most general f(R) gravity. Phenomenological considerations are given. (orig.)

Isolated torsion of fallopian tube in a post-menopausal patient: a case report.

Science.gov (United States)

Ozgun, Mahmut Tuncay; Batukan, Cem; Turkyilmaz, Cagdas; Serin, Ibrahim Serdar

2007-07-20

Isolated fallopian tube torsion after menopause is a rare condition. Here we report the second case of isolated fallopian tube torsion in a post-menopausal woman. A 55-year-old post-menopausal woman presented with right lower abdominal pain. Sonography depicted a simple cystic mass adjacent to the right uterine border. Laparatomy revealed torsion of the right fallopian tube together with a paraovarian cyst. Total abdominal hysterectomy and bilateral salpingo-oophorectomy was performed. Histopathological examination revealed a simple paraovarian cyst with severe congestion, necrosis and hemorrhage. Tubal torsion should be considered in the differential diagnosis of acute lower abdominal pain, even in post-menopausal women.

Contribution of the otoliths to the human torsional vestibulo-ocular reflex

NARCIS (Netherlands)

Groen, Eric; Bos, Jelte E.; De Graaf, Bernd

1999-01-01

The dynamic contribution of the otolith organs to the human ocular torsion response was examined during passive sinusoidal body roll about an earth-horizontal axis (varying otolith inputs) and about an earth-vertical axis (invariant otolith inputs). Torsional eye movements were registered in 5

Existence of Torsional Solitons in a Beam Model of Suspension Bridge

Science.gov (United States)

Benci, Vieri; Fortunato, Donato; Gazzola, Filippo

2017-11-01

This paper studies the existence of solitons, namely stable solitary waves, in an idealized suspension bridge. The bridge is modeled as an unbounded degenerate plate, that is, a central beam with cross sections, and displays two degrees of freedom: the vertical displacement of the beam and the torsional angles of the cross sections. Under fairly general assumptions, we prove the existence of solitons. Under the additional assumption of large tension in the sustaining cables, we prove that these solitons have a nontrivial torsional component. This appears relevant for security since several suspension bridges collapsed due to torsional oscillations.

Residual torsional properties of composite shafts subjected to impact loadings

International Nuclear Information System (INIS)

Sevkat, Ercan; Tumer, Hikmet

2013-01-01

Highlights: • Impact loading reduces the torsional strength of composite shaft. • Impact energy level determines the severity of torsional strength reduction. • Hybrid composite shafts can be manufactured by mixing two types of filament. • Maximum torque capacity of shafts can be estimated using finite element method. - Abstract: This paper presents an experimental and numerical study to investigate residual torsional properties of composite shafts subjected to impact loadings. E-glass/epoxy, carbon/epoxy and E-glass–carbon/epoxy hybrid composite shafts were manufactured by filament winding method. Composite shafts were impacted at 5, 10, 20 and 40 J energy levels. Force–time and energy–time histories of impact tests were recorded. One composite shaft with no impact, and four composite shafts with impact damage, five in total, were tested under torsion. Torque-twisting angle relations for each test were obtained. Reduction at maximum torque and maximum twisting angle induced by impact loadings were calculated. While 5 J impact did not cause significant reduction at maximum torque and maximum twisting angle, remaining impact loadings caused 34–67% reduction at maximum torque, and 30–61% reduction at maximum twisting angle. Reductions increased with increasing energy levels and varied depending on the material of composite shafts. The 3-D finite element (FE) software, Abaqus, incorporated with an elastic orthotropic model, was then used to simulate the torsion tests. Good agreement between experimental and numerical results was achieved

Prune belly syndrome, splenic torsion, and malrotation: a case report.

Science.gov (United States)

Tran, Sifrance; Grossman, Eric; Barsness, Katherine A

2013-02-01

An 18 year old male with a history of prune belly syndrome (PBS) presented with acute abdominal pain and palpable left upper quadrant mass. Computed tomography (CT) of the abdomen revealed a medialized spleen with a "whirl sign" in the splenic vessels, consistent with splenic torsion. Coincidentally, the small bowel was also noted to be on the right side of the abdomen, while the colon was located on the left, indicative of malrotation. Emergent diagnostic laparoscopy confirmed splenic torsion and intestinal malrotation. Successful laparoscopic reduction of the splenic torsion was achieved, however, conversion to an open procedure by a vertical midline incision was necessary owing to the patient's unique anatomy. Open splenopexy with a mesh sling and Ladd's procedure were subsequently performed. Malrotation and wandering spleen are known, rare associated anomalies in PBS; however, both have not been reported concurrently in a patient with PBS in the literature. In patients with PBS, acute abdominal pain, and an abdominal mass, high clinical suspicion for gastrointestinal malformations and prompt attention can result in spleen preservation and appropriate malrotation management. We present a case of a teenager who presented with a history of PBS, acute abdominal pain, and a palpable abdominal mass. The patient was found to have splenic torsion and intestinal malrotation. The clinical findings, diagnostic imaging, and surgical treatment options of splenic torsion are reviewed. Copyright © 2013 Elsevier Inc. All rights reserved.

Hollow-Core FRP–Concrete–Steel Bridge Columns under Torsional Loading

Directory of Open Access Journals (Sweden)

Sujith Anumolu

2017-11-01

Full Text Available This paper presents the behavior of hollow-core fiber-reinforced polymer–concrete–steel (HC-FCS columns under cyclic torsional loading combined with constant axial load. The HC-FCS consists of an outer fiber-reinforced polymer (FRP tube and an inner steel tube, with a concrete shell sandwiched between the two tubes. The FRP tube was stopped at the surface of the footing, and provided confinement to the concrete shell from the outer direction. The steel tube was embedded into the footing to a length of 1.8 times the diameter of the steel tube. The longitudinal and transversal reinforcements of the column were provided by the steel tube only. A large-scale HC-FCS column with a diameter of 24 in. (610 mm and applied load height of 96 in. (2438 mm with an aspect ratio of four was investigated during this study. The study revealed that the torsional behavior of the HC-FCS column mainly depended on the stiffness of the steel tube and the interactions among the column components (concrete shell, steel tube, and FRP tube. A brief comparison of torsional behavior was made between the conventional reinforced concrete columns and the HC-FCS column. The comparison illustrated that both column types showed high initial stiffness under torsional loading. However, the HC-FCS column maintained the torsion strength until a high twist angle, while the conventional reinforced concrete column did not.

Elevated temperature axial and torsional fatigue behavior of Haynes 188

Science.gov (United States)

Bonacuse, Peter J.; Kalluri, Sreeramesh

1992-06-01

The results of high-temperature axial and torsional low-cycle fatigue experiments performed on Haynes 188, a wrought cobalt-base superalloy, are reported. Fatigue tests were performed at 760 C in air on thin-walled tubular specimens at various ranges under strain control. Data are also presented for coefficient of thermal expansion, elastic modulus, and shear modulus at various temperatures from room to 1000 C, and monotonic and cyclic stress-strain curves in tension and in shear at 760 C. The data set is used to evaluate several multiaxial fatigue life models (most were originally developed for room temperature multiaxial life prediction) including von Mises equivalent strain range (ASME boiler and pressure vessel code), Manson-Halford, Modified Multiaxiality Factor (proposed here), Modified Smith-Watson-Topper, and Fatemi-Socie-Kurath. At von Mises equivalent strain ranges (the torsional strain range divided by the square root of 3, taking the Poisson's ratio to be 0.5), torsionally strained specimens lasted, on average, factors of 2 to 3 times longer than axially strained specimens. The Modified Multiaxiality Factor approach shows promise as a useful method of estimating torsional fatigue life from axial fatigue data at high temperatures. Several difficulties arose with the specimen geometry and extensometry used in these experiments. Cracking at extensometer probe indentations was a problem at smaller strain ranges. Also, as the largest axial and torsional strain range fatigue tests neared completion, a small amount of specimen buckling was observed.

Spontaneous compactification and Ricci-flat manifolds with torsion

International Nuclear Information System (INIS)

McInnes, B.

1985-06-01

The Freund-Rubin mechanism is based on the equation Rsub(ik)=lambdagsub(ik) (where lambda>0), which, via Myers' Theorem, implies ''spontaneous'' compactification. The difficulties connected with the cosmological constant in this approach can be resolved if torsion is introduced and lambda set equal to zero, but then compactification ''by hand'' is necessary, since the equation Rsub(ik)=0 can be satisfied both on compact and on non-compact manifolds. In this paper we discuss the global geometry of Ricci-flat manifolds with torsion, and suggest ways of restoring the ''spontaneity'' of the compactification. (author)

Research on torsional vibration modelling and control of printing cylinder based on particle swarm optimization

Science.gov (United States)

Wang, Y. M.; Xu, W. C.; Wu, S. Q.; Chai, C. W.; Liu, X.; Wang, S. H.

2018-03-01

The torsional oscillation is the dominant vibration form for the impression cylinder of printing machine (printing cylinder for short), directly restricting the printing speed up and reducing the quality of the prints. In order to reduce torsional vibration, the active control method for the printing cylinder is obtained. Taking the excitation force and moment from the cylinder gap and gripper teeth open & closing cam mechanism as variable parameters, authors establish the dynamic mathematical model of torsional vibration for the printing cylinder. The torsional active control method is based on Particle Swarm Optimization(PSO) algorithm to optimize input parameters for the serve motor. Furthermore, the input torque of the printing cylinder is optimized, and then compared with the numerical simulation results. The conclusions are that torsional vibration active control based on PSO is an availability method to the torsional vibration of printing cylinder.

Open string fluctuations in AdS space with and without torsion

DEFF Research Database (Denmark)

Larsen, A.L.; Lomholt, Michael Andersen

2003-01-01

The equations of motion and boundary conditions for the fluctuations around a classical open string, in a curved space-time with torsion, are considered in compact and world-sheet covariant form. The rigidly rotating open strings in anti-de Sitter space with and without torsion are investigated...

Contribution of facet joints, axial compression, and composition to human lumbar disc torsion mechanics.

Science.gov (United States)

Bezci, Semih E; Eleswarapu, Ananth; Klineberg, Eric O; O'Connell, Grace D

2018-02-12

Stresses applied to the spinal column are distributed between the intervertebral disc and facet joints. Structural and compositional changes alter stress distributions within the disc and between the disc and facet joints. These changes influence the mechanical properties of the disc joint, including its stiffness, range of motion, and energy absorption under quasi-static and dynamic loads. There have been few studies evaluating the role of facet joints in torsion. Furthermore, the relationship between biochemical composition and torsion mechanics is not well understood. Therefore, the first objective of this study was to investigate the role of facet joints in torsion mechanics of healthy and degenerated human lumbar discs under a wide range of compressive preloads. To achieve this, each disc was tested under four different compressive preloads (300-1200 N) with and without facet joints. The second objective was to develop a quantitative structure-function relationship between tissue composition and torsion mechanics. Facet joints have a significant contribution to disc torsional stiffness (∼60%) and viscoelasticity, regardless of the magnitude of axial compression. The findings from this study demonstrate that annulus fibrosus GAG content plays an important role in disc torsion mechanics. A decrease in GAG content with degeneration reduced torsion mechanics by more than an order of magnitude, while collagen content did not significantly influence disc torsion mechanics. The biochemical-mechanical and compression-torsion relationships reported in this study allow for better comparison between studies that use discs of varying levels of degeneration or testing protocols and provide important design criteria for biological repair strategies. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

A Case of Torsion of Gravid Uterus Caused by Leiomyoma

Directory of Open Access Journals (Sweden)

Gururaj Deshpande

2011-01-01

Full Text Available Uterine torsion during pregnancy is only sporadically reported in the literature. Here we present a case of leiomyoma causing uterine torsion in pregnancy and review the literature on etiology, diagnosis, and management. A 25-years-old primigravida with leiomyoma complicating pregnancy was admitted in our hospital with abdominal pain and uterine tenderness. She underwent emergency LSCS (lower segment cesarean section for fetal bradycardia. Intraoperatively, the uterus was rotated 180 degrees left to right. Inadvertent incision on the posterior wall was avoided by proper delineation of anatomy. Torsion was corrected by exteriorization of leiomyoma and uterus, and lower segment cesarean was carried out safely. Prompt recognition and management of this condition is necessary for better maternal and fetal outcome.

Knot soliton in DNA and geometric structure of its free-energy density.

Science.gov (United States)

Wang, Ying; Shi, Xuguang

2018-03-01

In general, the geometric structure of DNA is characterized using an elastic rod model. The Landau model provides us a new theory to study the geometric structure of DNA. By using the decomposition of the arc unit in the helical axis of DNA, we find that the free-energy density of DNA is similar to the free-energy density of a two-condensate superconductor. By using the φ-mapping topological current theory, the torus knot soliton hidden in DNA is demonstrated. We show the relation between the geometric structure and free-energy density of DNA and the Frenet equations in differential geometry theory are considered. Therefore, the free-energy density of DNA can be expressed by the curvature and torsion of the helical axis.

Doubly graded sigma model with torsion

International Nuclear Information System (INIS)

Kowalski-Glikman, J.

1986-08-01

Using the Hull-Witten construction we show how to introduce torsion to the doubly graded sigma model. This construction enables us to find a link between this model and the ten-dimensional supergravity theory in superspace. (Auth.)

Saccular impact on ocular torsion

NARCIS (Netherlands)

Graaf, B. de; Bos, J.E.; Groen, E.L.

1996-01-01

When someone is tilted laterally the sheer force on the maculae of the utriculus and the sacculus is described by the sine and the cosine of the angle of tilt, respectively. So both the sacculus and the utriculus are stimulated, but in the litera-ture ocular torsion is normally attributed to

Transcription facilitated genome-wide recruitment of topoisomerase I and DNA gyrase.

Science.gov (United States)

Ahmed, Wareed; Sala, Claudia; Hegde, Shubhada R; Jha, Rajiv Kumar; Cole, Stewart T; Nagaraja, Valakunja

2017-05-01

Movement of the transcription machinery along a template alters DNA topology resulting in the accumulation of supercoils in DNA. The positive supercoils generated ahead of transcribing RNA polymerase (RNAP) and the negative supercoils accumulating behind impose severe topological constraints impeding transcription process. Previous studies have implied the role of topoisomerases in the removal of torsional stress and the maintenance of template topology but the in vivo interaction of functionally distinct topoisomerases with heterogeneous chromosomal territories is not deciphered. Moreover, how the transcription-induced supercoils influence the genome-wide recruitment of DNA topoisomerases remains to be explored in bacteria. Using ChIP-Seq, we show the genome-wide occupancy profile of both topoisomerase I and DNA gyrase in conjunction with RNAP in Mycobacterium tuberculosis taking advantage of minimal topoisomerase representation in the organism. The study unveils the first in vivo genome-wide interaction of both the topoisomerases with the genomic regions and establishes that transcription-induced supercoils govern their recruitment at genomic sites. Distribution profiles revealed co-localization of RNAP and the two topoisomerases on the active transcriptional units (TUs). At a given locus, topoisomerase I and DNA gyrase were localized behind and ahead of RNAP, respectively, correlating with the twin-supercoiled domains generated. The recruitment of topoisomerases was higher at the genomic loci with higher transcriptional activity and/or at regions under high torsional stress compared to silent genomic loci. Importantly, the occupancy of DNA gyrase, sole type II topoisomerase in Mtb, near the Ter domain of the Mtb chromosome validates its function as a decatenase.

Torsional Vibration in the National Wind Technology Center’s 2.5-Megawatt Dynamometer

Energy Technology Data Exchange (ETDEWEB)

Sethuraman, Latha [National Renewable Energy Lab. (NREL), Golden, CO (United States); Keller, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wallen, Robb [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-08-31

This report documents the torsional drivetrain dynamics of the NWTC's 2.5-megawatt dynamometer as identified experimentally and as calculated using lumped parameter models using known inertia and stiffness parameters. The report is presented in two parts beginning with the identification of the primary torsional modes followed by the investigation of approaches to damp the torsional vibrations. The key mechanical parameters for the lumped parameter models and justification for the element grouping used in the derivation of the torsional modes are presented. The sensitivities of the torsional modes to different test article properties are discussed. The oscillations observed from the low-speed and generator torque measurements were used to identify the extent of damping inherently achieved through active and passive compensation techniques. A simplified Simulink model of the dynamometer test article integrating the electro-mechanical power conversion and control features was established to emulate the torque behavior that was observed during testing. The torque response in the high-speed, low-speed, and generator shafts were tested and validated against experimental measurements involving step changes in load with the dynamometer operating under speed-regulation mode. The Simulink model serves as a ready reference to identify the torque sensitivities to various system parameters and to explore opportunities to improve torsional damping under different conditions.

Torsion of the Vermiform Appendix: A Case Report and Review of Literature

Science.gov (United States)

Hassan, Wan Amir Wan; Tay, Yeng Kwang; Ghadiri, Marjan

2018-01-01

Patient: Male, 30 Final Diagnosis: Torsion of appendix Symptoms: Abdominal pain • anorexia • nausea Medication: — Clinical Procedure: Laparoscopic appendicectomy Specialty: Surgery Objective: Rare disease Background: Torsion of the vermiform appendix is a rare condition that presents with symptoms analogous to those of common acute appendicitis; therefore, it is often diagnosed during surgery. It was first described by Payne et al. in 1918. Since then, there has been wide recognition of a primary and a secondary form of the condition, affecting both the pediatric and adult populations. We present a case of an adult patient and conducted a literature review in the adult demographic. Case Report: We report the case of a 30-year-old man who presented with clinically acute appendicitis. Laparoscopically, we diagnosed a torsion of the vermiform appendix secondary to a mucocele process. Histology confirmed a low-grade mucinous cystoadenoma, with a hemorrhagic necrosis of the wall, in keeping with torsion. Conclusions: Torsion of the vermiform appendix is a rare condition that presents similar to acute appendicitis, and therefore is often diagnosed intraoperatively. Since first described, 33 cases in adults were identified in the English literature, and recognition of a primary or secondary form has emerged. Preoperative radiological imaging is rarely useful in diagnosis. To the best of our knowledge, this is the eighth reported case in the English literature of a torsion of the vermiform appendix secondary to a mucinous cystoadenoma. PMID:29588439

The g - 2 muon anomaly in di-muon production with the torsion in LHC

Science.gov (United States)

Syromyatnikov, A. G.

2016-06-01

It was considered within the framework of the conformal gauge gravitational theory CGTG coupling of the standard model fermions to the axial torsion and preliminary discusses the impact of extra dimensions, in particular, in a five-dimensional space-time with Randall-Sundrum metric, where the fifth dimension is compactified on an S1/Z 2 orbifold, which as it turns out is conformally to the fifth dimension flat Euclidean space with permanent trace of torsion, with a compactification radius R in terms of the radius of a CGTG gravitational screening, through torsion in a process Z → μ+μ- and LHC data. In general, have come to the correct set of the conformal calibration curvature the Faddeev-Popov diagram technique type, that follows directly from dynamics. This leads to the effect of restrictions on neutral spin currents of gauge fields by helicity and the Regge’s form theory. The diagrams reveals the fact of opening of the fine spacetime structure in a process pp → γ/Z/T → μ+μ- with a center-of-mass energy of 14TeV, indicated by dotted lines and texture columns, as a result of p-p collision on 1.3 ṡ 10-18cm scales from geometric shell gauge bosons of the SM continued by the heavy axial torsion resonance, and even by emerging from the inside into the outside of the ultra-light (freely-frozen in muon’s spin) axial torsion. We then evaluate the contribution of the torsion to the muon anomaly to derive new constraints on the torsion parameters. It was obtained that on the πN scattering through the exchange of axial torsion accounting, the nucleon anomalous magnetic moment in the eikonal phase leads to additive additives which is responsible for the spin-flip in the scattering process, the scattering amplitude is classical and characterized by a strong the torsion coupling ηT≅1. So the scattering of particles, occurs as on the Coulomb center with the charge fT This is the base model which is the g-2 muon anomaly. The muon anomaly contribution due to

Success of torsional correction surgery after failed surgeries for patellofemoral pain and instability

OpenAIRE

Stevens, Peter M.; Gililland, Jeremy M.; Anderson, Lucas A.; Mickelson, Jennifer B.; Nielson, Jenifer; Klatt, Joshua W.

2013-01-01

Torsional deformities of the femur and/or tibia often go unrecognized in adolescents and adults who present with anterior knee pain, and patellar maltracking or instability. While open and arthroscopic surgical techniques have evolved to address these problems, unrecognized torsion may compromise the outcomes of these procedures. We collected a group of 16 consecutive patients (23 knees), with mean age of 17, who had undergone knee surgery before torsion was recognized and subsequently treate...

Some exact solutions with torsion in 5D Einstein-Gauss-Bonnet gravity

International Nuclear Information System (INIS)

Canfora, F.; Giacomini, A.; Willison, S.

2007-01-01

Exact solutions with torsion in Einstein-Gauss-Bonnet gravity are derived. These solutions have a cross product structure of two constant curvature manifolds. The equations of motion give a relation for the coupling constants of the theory in order to have solutions with nontrivial torsion. This relation is not the Chern-Simons combination. One of the solutions has an AdS 2 xS 3 structure and is so the purely gravitational analogue of the Bertotti-Robinson space-time where the torsion can be seen as the dual of the covariantly constant electromagnetic field

Lung lobe torsion in dogs: 22 cases (1981-1999).

Science.gov (United States)

Neath, P J; Brockman, D J; King, L G

2000-10-01

To identify breed disposition, postoperative complications, and outcome in dogs with lung lobe torsion. Retrospective study. 22 client-owned dogs. Information on signalment; history; clinical findings; results of clinicopathologic testing, diagnostic imaging, and pleural fluid analysis; surgical treatment; intra- and postoperative complications; histologic findings; and outcome were obtained from medical records. All 22 dogs had pleural effusion; dyspnea was the most common reason for examination. Fifteen dogs were large deep-chested breeds; 5 were toy breeds. Afghan Hounds were overrepresented, compared with the hospital population. One dog was euthanatized without treatment; the remaining dogs underwent exploratory thoracotomy and lung lobectomy. Eleven dogs recovered from surgery without complications, but 3 of these later died of thoracic disease. Four dogs survived to discharge but had clinically important complications within 2 months, including chylothorax, mediastinal mesothelioma, gastric dilatation, and a second lung lobe torsion. Six dogs died or were euthanatized within 2 weeks after surgery because of acute respiratory distress syndrome, pneumonia, septic shock, pneumothorax, or chylothorax. Chylothorax was diagnosed in 8 of the 22 dogs, including 4 Afghan Hounds. Results suggest that lung lobe torsion is rare in dogs and develops most frequently in large deep-chested dogs, particularly Afghan Hounds. Other predisposing causes were not identified, but an association with chylothorax was evident, especially in Afghan Hounds. Prognosis for dogs with lung lobe torsion was fair to guarded.

Influence of cyclic torsional preloading on cyclic fatigue resistance of nickel - titanium instruments.

Science.gov (United States)

Pedullà, E; Lo Savio, F; Boninelli, S; Plotino, G; Grande, N M; Rapisarda, E; La Rosa, G

2015-11-01

To evaluate the effect of different torsional preloads on cyclic fatigue resistance of endodontic rotary instruments constructed from conventional nickel-titanium (NiTi), M-Wire or CM-Wire. Eighty new size 25, 0.06 taper Mtwo instruments (Sweden & Martina), size 25, 0.06 taper HyFlex CM (Coltene/Whaledent, Inc) and X2 ProTaper Next (Dentsply Maillefer) were used. The Torque and distortion angles at failure of new instruments (n = 10) were measured, and 0% (n = 10), 25%, 50% and 75% (n = 20) of the mean ultimate torsional strength as preloading condition were applied according to ISO 3630-1 for each brand. The twenty files tested for every extent of preload were subjected to 20 or 40 torsional cycles (n = 10). After torsional preloading, the number of cycles to failure was evaluated in a simulated canal with 60° angle of curvature and 5 mm of radius of curvature. Data were analysed using two-way analysis of variance. The fracture surface of each fragment was examined with a scanning electron microscope (SEM). Data were analysed by two-way analyses of variance. Preload repetitions did not influence the cyclic fatigue of the three brands; however, the 25%, 50% and 75% torsional preloading significantly reduced the fatigue resistance of all instruments tested (P 0.05). Torsional preloads reduced the cyclic fatigue resistance of conventional and treated (M-wire and CM-wire) NiTi rotary instruments except for size 25, 0.06 taper HyFlex CM instruments with a 25% of torsional preloading. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Post-surgery lung torsion and haemorrhagic infarction - a case report

International Nuclear Information System (INIS)

Noemayr, A.; Schmitt, R.; Wichert, C.; Bautz, W.; Rupprecht, H.

1998-01-01

Lung or lobe torsion may occur after thoracic surgery, chest trauma, pneumothorax, pneumonia, or even spontaneously. Lung infarction is a possible complication. The characteristic radiological signs on plain radiographs are opacification and/or displacement of lobes and hilus structures. CT-signs of haemorrhagic infarction are opacification and multiple punctate gas accumulations. The bronchus could be interrupted at the level of the torsion (''bronchus cutoff''). (orig.) [de

Non-relativistic correspondence of Dirac equation with external electromagnetic field and space-time torsion

International Nuclear Information System (INIS)

Goncalves, Bruno; Dias Junior, Mario Marcio

2013-01-01

Full text: The discussion of experimental manifestations of torsion at low energies is mainly related to the torsion-spin interaction. In this respect the behavior of Dirac field and the spinning particle in an external torsion field deserves and received very special attention. In this work, we consider the combined action of torsion and magnetic field on the massive spinor field. In this case, the Dirac equation is not straightforward solved. We suppose that the spinor has two components. The equations have mixed terms between the two components. The electromagnetic field is introduced in the action by the usual gauge transformation. The torsion field is described by the field S μ . The main purpose of the work is to get an explicit form to the equation of motion that shows the possible interactions between the external fields and the spinor in a Hamiltonian that is independent to each component. We consider that S 0 is constant and is the unique non-vanishing term of S μ . This simplification is taken just to simplify the algebra, as our main point is not to describe the torsion field itself. In order to get physical analysis of the problem, we consider the non-relativistic approximation. The final result is a Hamiltonian that describes a half spin field in the presence of electromagnetic and torsion external fields. (author)

Torsion, supersymmetry, and the heterotic string

International Nuclear Information System (INIS)

Curtright, T.

1985-01-01

The dynamical effects of torsion are summarized for bosonic and supersymmetric sigma models in two spacetime dimensions. Analogous structure for the heterotic superstring is discussed, including the presence of nonlinear realizations of supersymmetry on the world-sheet. 27 refs

Massless fermions and Kaluza--Klein theory with torsion

International Nuclear Information System (INIS)

Wu, Y.; Zee, A.

1984-01-01

A pure Kaluza--Klein theory contains no massless fermion in four-dimensional theory. We investigate the effect of introducing torsion on the internal manifold and find that there are massless fermions. The hope is that given an isometry group the representation to which these fermions belong is fixed, in contrast to the situation in Yang--Mills theory. We show that this is indeed the case, but the representations do not appear to be the ones favored by current theoretical prejudice. The cases with parallelizable torsions on a group manifold as the internal manifold are analyzed in detail

Singularities and n-dimensional black holes in torsion theories

Energy Technology Data Exchange (ETDEWEB)

Cembranos, J.A.R.; Valcarcel, J. Gigante; Torralba, F.J. Maldonado, E-mail: cembra@fis.ucm.es, E-mail: jorgegigante@ucm.es, E-mail: fmaldo01@ucm.es [Departamento de Física Teórica I, Universidad Complutense de Madrid, E-28040 Madrid (Spain)

2017-04-01

In this work we have studied the singular behaviour of gravitational theories with non symmetric connections. For this purpose we introduce a new criteria for the appearance of singularities based on the existence of black/white hole regions of arbitrary codimension defined inside a spacetime of arbitrary dimension. We discuss this prescription by increasing the complexity of the particular torsion theory under study. In this sense, we start with Teleparallel Gravity, then we analyse Einstein-Cartan theory, and finally dynamical torsion models.

Simple currents versus orbifolds with discrete torsion -- a complete classification

CERN Document Server

Kreuzer, M

1994-01-01

We give a complete classification of all simple current modular invariants, extending previous results for $(\\Zbf_p)^k$ to arbitrary centers. We obtain a simple explicit formula for the most general case. Using orbifold techniques to this end, we find a one-to-one correspondence between simple current invariants and subgroups of the center with discrete torsions. As a by-product, we prove the conjectured monodromy independence of the total number of such invariants. The orbifold approach works in a straightforward way for symmetries of odd order, but some modifications are required to deal with symmetries of even order. With these modifications the orbifold construction with discrete torsion is complete within the class of simple current invariants. Surprisingly, there are cases where discrete torsion is a necessity rather than a possibility.

Simple currents versus orbifolds with discrete torsion - a complete classification

International Nuclear Information System (INIS)

Kreuzer, M.; Schellekens, A.N.

1993-01-01

We give a complete classification of all simple current modular invariants, extending previous results for (Z p ) k to arbitrary centers. We obtain a simple explicit formula for the most general case. Using orbifold techniques to this end, we find a one-to-one correspondence between simple current invariants and subgroups of the center with discrete torsions. As a by-product, we prove the conjectured monodromy independence of the total number of such invariants. The orbifold approach works in a straightforward way for symmetries of odd order, but some modifications are required to deal with symmetries of even order. With these modifications the orbifold construction with discrete torsion is complete within the class of simple current invariants. Surprisingly, there are cases where discrete torsion is a necessity rather than a possibility. (orig.)

Torsional Topological Invariants (and their relevance for real life)

CERN Document Server

Chandia, O; Chandia, Osvaldo; Zanelli, Jorge

1997-01-01

The existence of topological invariants analogous to Chern/Pontryagin classes for a standard $SO(D)$ or SU(N) connection, but constructed out of the torsion tensor, is discussed. These invariants exhibit many of the features of the Chern/Pontryagin invariants: they can be expressed as integrals over the manifold of local densities and take integer values on compact spaces without boundary; their spectrum is determined by the homotopy groups determined by the connection bundle but depend also on the bundle of local orthonormal frames on the tangent space of the manifold. It is shown that in spacetimes with nonvanishing torsion there can occur topologically stable configurations associated with the frame bundle which are independent of the curvature. Explicit examples of topologically stable configurations carrying nonvanishing instanton number in four and eight dimensions are given, and they can be conjectured to exist in dimension $4k$. It is also shown that the chiral anomaly in a spacetime with torsion rece...

Intravitreal Phacoemulsification Using Torsional Handpiece for Retained Lens Fragments.

Science.gov (United States)

Kumar, Vinod; Takkar, Brijesh

2016-01-01

To evaluate the results of intravitreal phacoemulsification with torsional hand piece in eyes with posteriorly dislocated lens fragments. In this prospective, interventional case series, 15 eyes with retained lens fragments following phacoemulsification were included. All patients underwent standard three-port pars plana vitrectomy and intravitreal phacoemulsification using sleeveless, torsional hand piece (OZiL™, Alcon's Infiniti Vision System). Patients were followed up for a minimum of six months to evaluate the visual outcomes and complications. The preoperative best-corrected visual acuity (BCVA) ranged from light perception to 0.3. No complications such as thermal burns of the scleral wound, retinal damage due to flying lens fragments, or difficult lens aspiration occurred during intravitreal phacoemulsification. Mean post-operative BCVA at the final follow-up was 0.5. Two eyes developed cystoid macular edema, which was managed medically. No retinal detachment was noted. Intravitreal phacoemulsification using torsional hand piece is a safe and effective alternative to conventional longitudinal phacofragmentation.

Intravitreal Phacoemulsification Using Torsional Handpiece for Retained Lens Fragments

Science.gov (United States)

Kumar, Vinod; Takkar, Brijesh

2016-01-01

Purpose: To evaluate the results of intravitreal phacoemulsification with torsional hand piece in eyes with posteriorly dislocated lens fragments. Methods: In this prospective, interventional case series, 15 eyes with retained lens fragments following phacoemulsification were included. All patients underwent standard three-port pars plana vitrectomy and intravitreal phacoemulsification using sleeveless, torsional hand piece (OZiL™, Alcon's Infiniti Vision System). Patients were followed up for a minimum of six months to evaluate the visual outcomes and complications. Results: The preoperative best-corrected visual acuity (BCVA) ranged from light perception to 0.3. No complications such as thermal burns of the scleral wound, retinal damage due to flying lens fragments, or difficult lens aspiration occurred during intravitreal phacoemulsification. Mean post-operative BCVA at the final follow-up was 0.5. Two eyes developed cystoid macular edema, which was managed medically. No retinal detachment was noted. Conclusion: Intravitreal phacoemulsification using torsional hand piece is a safe and effective alternative to conventional longitudinal phacofragmentation. PMID:27621783

Massive torsion modes, chiral gravity and the Adler-Bell-Jackiw anomaly

International Nuclear Information System (INIS)

Chang, Lay Nam; Soo Chopin

2003-01-01

Regularization of quantum field theories introduces a mass scale which breaks axial rotational and scaling invariances. We demonstrate from first principles that axial torsion and torsion trace modes have non-transverse vacuum polarization tensors, and become massive as a result. The underlying reasons are similar to those responsible for the Adler-Bell-Jackiw (ABJ) and scaling anomalies. Since these are the only torsion components that can couple minimally to spin-1/2 particles, the anomalous generation of masses for these modes, naturally of the order of the regulator scale, may help to explain why torsion and its associated effects, including CPT violation in chiral gravity, have so far escaped detection. As a simpler manifestation of the reasons underpinning the ABJ anomaly than triangle diagrams, the vacuum polarization demonstration is also pedagogically useful. In addition, it is shown that the teleparallel limit of a Weyl fermion theory coupled only to the left-handed spin connection leads to a counter term which is the Samuel-Jacobson-Smolin action of chiral gravity in four dimensions

Massive torsion modes, chiral gravity and the Adler-Bell-Jackiw anomaly

Energy Technology Data Exchange (ETDEWEB)

Chang, Lay Nam [Department of Physics, Virginia Tech., Blacksburg, VA 24061-0435 (United States); Soo Chopin [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China)

2003-04-07

Regularization of quantum field theories introduces a mass scale which breaks axial rotational and scaling invariances. We demonstrate from first principles that axial torsion and torsion trace modes have non-transverse vacuum polarization tensors, and become massive as a result. The underlying reasons are similar to those responsible for the Adler-Bell-Jackiw (ABJ) and scaling anomalies. Since these are the only torsion components that can couple minimally to spin-1/2 particles, the anomalous generation of masses for these modes, naturally of the order of the regulator scale, may help to explain why torsion and its associated effects, including CPT violation in chiral gravity, have so far escaped detection. As a simpler manifestation of the reasons underpinning the ABJ anomaly than triangle diagrams, the vacuum polarization demonstration is also pedagogically useful. In addition, it is shown that the teleparallel limit of a Weyl fermion theory coupled only to the left-handed spin connection leads to a counter term which is the Samuel-Jacobson-Smolin action of chiral gravity in four dimensions.

Does Foot Massage Relieve Acute Postoperative Pain? A Literature Review

Directory of Open Access Journals (Sweden)

Chanif Chanif

2013-01-01

Full Text Available Purpose: This study aimed to examine the current state of knowledge regarding foot massageto determine if foot massage has an effect on relieving acute postoperative pain.Method: The following questions were used to guide this review: How does pain occur?What is the pain management modalities used in relieving acute postoperative pain? Does footmassage relieve acute postoperative pain? A comprehensive systematic search of publishedliterature and journal articles from Science Direct, CINAHL, PubMed, ProQuest and fromrelevant textbooks was conducted. The universal case entry website, Google-scholar was usedas well. The following keywords were used: foot massage, pain management, andpostoperative pain. Eight studies on foot massage and more than thirty related articles werereviewed.Result: Postoperative pain is caused by tissue damage that induces release of chemicalmediators from the surgical wound. The four processes of pain are transduction, transmission,perception and modulation. Pain medication is the goal standard for acute postoperative painrelief. In addition, foot massage is a modality that can be used in relieving acute postoperativepain. Massage stimulates large nerve fibers and dermatome layers which contain tactile andpressure receptors. The receptors subsequently transmit the nerve impulse to the centralnervous system. The gate control system in the dorsal horn is activated through the inhibitoryinterneuron, thus closing the gate. Subsequently, the brain does not receive the pain message.Eight reviewed studies demonstrated that foot massage relieves acute postoperative pain.However, there were some methodological limitations of these studies.Conclusion: It is recommended to examine the effect of foot massage on acute postoperativepain with high homogenous samples using various duration of massage and range of time forpain measurement at different settings.Key words: foot massage, pain management and postoperative pain.

Added value of using a CT coronal reformation to diagnose adnexal torsion

Energy Technology Data Exchange (ETDEWEB)

Jung, Sung Il; Park, Hee Sun; Yim, Young Hee; Jeon, Hae Jeong; Yu, Mi Hye; Kim, Young Jun [Dept. of Radiology, Konkuk University School of Medicine, Research Institute of Medical Science, Seoul (Korea, Republic of); Jeong, Kyung Ah [Dept. of Obstetrics and Gynecology, School of Medicine, Ewha Womans University, Seoul (Korea, Republic of)

2015-08-15

To evaluate the increased value of using coronal reformation of a transverse computed tomography (CT) scan for detecting adnexal torsion. This study included 106 woman suspected of having adnexal torsion who underwent CT with coronal reformations and subsequent surgical exploration. Two readers independently recorded the CT findings, such as the thickening of a fallopian tube, twisting of the adnexal pedicle, eccentric smooth wall thickening of the torsed adnexal mass, eccentric septal thickening of the torsed adnexal mass, eccentric poor enhancement of the torsed adnexal mass, uterine deviation to the twisted side, ascites or infiltration of pelvic fat, and the overall impression of adnexal torsion with a transverse scan alone or combined with coronal reformation and a transverse scan. The areas under the receiver operating characteristic curves (AUCs), sensitivity, specificity, and positive predictive value were used to compare diagnostic performance. Fifty-two patients were confirmed to have adnexal torsion. The addition of coronal reformations to the transverse scan improved AUCs for readers 1 and 2 from 0.74 and 0.75 to 0.92 and 0.87, respectively, for detecting adnexal torsion (p < 0.001 and p = 0.004, respectively). Sensitivity of CT for detecting twisting of the adnexal pedicle increased significantly for readers 1 and 2 from 0.27 and 0.29 with a transverse scan alone to 0.79 and 0.77 with a combined coronal reformation and a transverse scan, respectively (p < 0.001 and p < 0.001, respectively). Use of a coronal reformation with transverse CT images improves detection of adnexal torsion.

Comparison of endothelial changes and power settings between torsional and longitudinal phacoemulsification.

Science.gov (United States)

Reuschel, Anna; Bogatsch, Holger; Barth, Thomas; Wiedemann, Renate

2010-11-01

To compare the intraoperative and postoperative outcomes of conventional longitudinal phacoemulsification and torsional phacoemulsification. Department of Ophthalmology, University of Leipzig, Germany. Randomized single-center clinical trial. Eyes with senile cataract were randomized to have phacoemulsification using the Infiniti Vision System and the torsional mode (OZil) or conventional longitudinal mode. Primary outcomes were corrected distance visual acuity (CDVA) and central endothelial cell density (ECD), calculated according to the Conference on Harmonisation-E9 Guidelines in which missing values were substituted by the median in each group (primary analysis) and the loss was then calculated using actual data (secondary analysis). Secondary outcomes were ultrasound (US) time, cumulative dissipated energy (CDE), and percentage total equivalent power in position 3. Postoperative follow-up was at 3 months. The mean preoperative CDVA was 0.41 logMAR in the torsional group and 0.38 logMAR in the longitudinal group, improving to 0.07 logMAR postoperatively in both groups. The mean ECD loss was 7.2% ± 4.6% in the torsional group (72 patients) and 7.1% ± 4.4% in the longitudinal group (76 patients), with no statistically significant differences in the primary analysis (P = .342) or secondary analysis (P = .906). The mean US time, CDE, and percentage total equivalent power in position 3 were statistically significantly lower in the torsional group (98 patients) than in the longitudinal group (94 patients) (P<.001). The torsional mode was as safe as the longitudinal mode in phacoemulsification for age-related cataract. Copyright © 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Electronic transport in torsional strained Weyl semimetals

Science.gov (United States)

Soto-Garrido, Rodrigo; Muñoz, Enrique

2018-05-01

In a recent paper (Muñoz and Soto-Garrido 2017 J. Phys.: Condens. Matter 29 445302) we have studied the effects of mechanical strain and magnetic field on the electronic transport properties in graphene. In this article we extended our work to Weyl semimetals (WSM). We show that although the WSM are 3D materials, most of the analysis done for graphene (2D material) can be carried out. In particular, we studied the electronic transport through a cylindrical region submitted to torsional strain and external magnetic field. We provide exact analytical expressions for the scattering cross section and the transmitted electronic current. In addition, we show the node-polarization effect on the current and propose a recipe to measure the torsion angle from transmission experiments.

RELIEVE: A FORTRAN 77 program for numerical and graphical processing of digital topographic maps

International Nuclear Information System (INIS)

Sanchez, J.J.; Gorostiza, C.

1995-01-01

The RELIEVE program was developed in order to its integration with the expert system SIRENAS, in the frame of the Industrial Risks Programme, within the CIEMAT center. For accomplishing this mentioned system, arose the necessity of an additional component enabled for analyzing the topography (relieve) of the territory in which the focused site is located. That is just the mission of the RELIEVE program. Basically RELIEVE analyses the digitalized data points of a determinate topographic area, around a location of interest. The program allows us estimation by numerical techniques, using IMSL library, of the deep width, and other geometrical characteristics of the valley that is involved in. Optionally RELIEVE produces also graphical outputs concerning 3D representation of topographical map, level curves, sections of interest considered in the valley, etc., by means of the DISSPLA II library, running in the IBM system of the CIEMAT. (Author) 5 refs

Torsion of the fallopian the mimicking appendicitis in a pregnant woman

International Nuclear Information System (INIS)

Tapia-Vine, M.; Pedrosa, I.; Escribano, N.

2000-01-01

Isolated torsion of the fallopian tube is an uncommon entity. Given the difficulties involved in the preoperative diagnosis, the ultrasound findings characteristic of this anomaly are not widely known. We present a case of tubal torsion associated with a cyst, describing the ultrasound images in our case and those reported in the literature. (Author) 18 refs

Uterine Torsion in a West African Dwarf Ewe in Ibadan, Nigeria ...

African Journals Online (AJOL)

Keywords: Uterine torsion, West African Dwarf Ewe, Ibadan A case of uterine torsion in a 21/2 year old pluriparous West Africa Dwarf (WAD) ewe raised semi intensively with adequate veterinary care before the death of the dam and the lamb is presented. The dam had been off feed for 3 days and was found straining a night ...

Coupled lateral-torsional response of equipment mounted in CANDU nuclear power plants

International Nuclear Information System (INIS)

Ishac, M.F.; Heidebrecht, A.C.

1979-01-01

In this paper, a coupled lateral torsional model (CLTM) is developed as a modification of the uncoupled lateral torsional model (ULTM) by including the torsional degree of freedom for each mass point and taking into consideration the effect of eccentricities between the centers of mass and rigidity at each floor level. The lateral and rotational time-histories at each floor level are characterized by lateral and rotational floor response spectra at the mass centroid. These time-histories are also combined to determine the lateral floor response spectra at the extreme edges of each floor mass. (orig.)

Fiber-Optic Sensors for Measurements of Torsion, Twist and Rotation: A Review.

Science.gov (United States)

Budinski, Vedran; Donlagic, Denis

2017-02-23

Optical measurement of mechanical parameters is gaining significant commercial interest in different industry sectors. Torsion, twist and rotation are among the very frequently measured mechanical parameters. Recently, twist/torsion/rotation sensors have become a topic of intense fiber-optic sensor research. Various sensing concepts have been reported. Many of those have different properties and performances, and many of them still need to be proven in out-of-the laboratory use. This paper provides an overview of basic approaches and a review of current state-of-the-art in fiber optic sensors for measurements of torsion, twist and/or rotation.Invited Paper.

The incidence of isolated penile torsion in North India: A study of 5,018 male neonates.

Science.gov (United States)

Bhat, Amilal; Bhat, Mahakshit; Kumar, Vinay; Goyal, Suresh; Bhat, Akshita; Patni, Madhu

2017-10-01

Congenital penile torsion is a three-dimensional deformity with helical rotation of the distal corporal bodies with the penile crurae remaining fixed to the pubic rami. The first case of congenital penile torsion (hypospadias) was described in 1857. Isolated penile torsion is an under-reported anomaly. The reported incidence of isolated penile torsion is 1.7-27% and severe torsion is 0.7%. There are no studies available from Indian subcontinent on the incidence of isolated penile torque. The objective of this study was to determine the overall incidence of isolated penile torque in a north Indian population. A prospective study of deliveries of male children was conducted at our institute between April 2014 and June 2015. Penile torsion was measured using a small protractor either by the deviation of the median raphae or the direction of the meatus. Data were collected on the incidence of congenital isolated penile torsion, including the degree and direction (left or right) of torsion. Torsion was classified as mild (900). Statistical analysis was done using the chi-square test with variables of age and parity of the mother and weight of the child. There were 99 cases of isolated penile torque among 5018 male neonates assessed for penile torque. The incidence of isolated penile torque was 19.7 per 1000 births. The degree of torsion varied from 30 to 110° (average 51.46°). Seventy-nine percent (79%) of them had left side and 21% had right side torque (4:1). The degree of torsion was mild in 30%, with 20% having left side torque and 10% having right side torque (2:1). A moderate degree of torsion was seen in 69%: 84% of them had left torque and only 16% had right sided torque (5:1). Only one patient had severe left torque. The incidence of isolated congenital penile torsion was highest in the maternal age group of >30 years followed by the 26-30-year age group, and was lowest in 21-25 year age group. In multiparous women, the incidence of isolated congenital penile

Human tibial torsion - Morphometric assessment and clinical relevance

Directory of Open Access Journals (Sweden)

Swati Gandhi

2014-02-01

Full Text Available Background: Tibial torsion is an important anatomical parameter in clinical practice and displays variability among individuals. These variations are extremely significant in view of alignment guides such as those related to rotational landmarks of tibia in total knee arthroplasty. Further, precise knowledge and information pertaining to angle of tibial torsion also helps in correction of traumatic malunion or congenital maltorsion of tibia. Methods: The present study was carried out to determine the angle of tibial torsion in 100 adult dry tibia bones in the Department of Anatomy, Government Medical College, Amritsar. The study group comprised 50 males and 50 females with equal number of right- and left-sided bones. The measurements were meticulously recorded and the data were subjected to statistical analysis. The results were analyzed and discussed in the light of existing literature. Results: On the right side, it was found to be 29.84° ± 4.86°° (range = 22.00° -38.00° in males and 28.92° ± 5.10°° (range = 15.00°-38.00° in females. On the left side, it was found to be 28.00° ± 4.94°° (range = 20.00°-40.00°° in males and 28.12° ± 4.28°° (range = 20.00°-37.00°° in females. Conclusion: The present study is an endeavor to provide baseline data with reference to the angle of tibial torsion in the Indian population. The results of the study assume special importance in view of the technical advancements in reconstructive surgical procedures in orthopedic practice.

Gastrointestinal torsions and intussusception in northern koalas (Phascolarctos cinereus) at San Diego Zoo (1976-2012).

Science.gov (United States)

Joyce-Zuniga, Nicole M; Roesler, Jennifer; Andrus, Chris Hamlin; Sutherland-Smith, Meg; Rideout, Bruce A; Pye, Geoffrey W

2014-03-01

The recent classification as threatened status of the northern koala (Phascolarctos cinereus) by the Australian Government highlights the importance of the conservation and health management of this iconic Australian marsupial. This case series describes gastrointestinal torsion and intussusception in six northern koalas (three males, three females, 2-11 yr old) at the San Diego Zoo from 1976 to 2012. Two koalas died shortly after presentation. Diagnoses of ileocecal intussusception, resulting from enteritis in one case and cecal torsion in the other, were made at postmortem examination. One koala died 4 days after an exploratory laparotomy, with negative findings, and an acute double colonic intussusception was diagnosed at postmortem examination. Two small intestinal mesenteric torsion and one proximal colon mesenteric torsion cases were successfully corrected surgically. In the case of colonic mesenteric torsion, the koala had recurrent clinical signs 2 wk later, and a second surgery requiring resection and anastomosis of ischemic jejunum was performed, with the koala dying shortly afterward. One koala with small intestinal torsion had a recurrence of torsion 22 mo later and subsequently died. The koala with the second case of small intestinal torsion remains alive 14 mo postsurgical correction. All six koalas presented with signs of colic that included anorexia, lethargy, depression, acute abdominal distension, abdominal stretching, decreased fecal output, open-mouth gasping, or a combination of symptoms. Abdominal radiographs may show stacked gastrointestinal linear gas patterns and contrast stasis. Prevalence of torsion and intussusception is low at this institution (2%), although recurrence in individuals is common (50%) and overall survival is poor (83%), which emphasizes the importance of timely recognition, surgical correction, and postoperative management. While inciting etiologies were unable to be determined in these cases, monitoring generalized

Effect of bilateral superior oblique split lengthening on torsion

Directory of Open Access Journals (Sweden)

Jitendra Jethani

2015-01-01

Full Text Available Introduction: Superior oblique split lengthening (SOSL is done for weakening of superior oblique. It corrects the superior oblique overaction (SOOA and A pattern. Its effect on the torsion of the eye is not known. We present our data on the effect of this particular procedure on torsion. Materials and Methods: We did a study of 16 patients (32 eyes who underwent bilateral SOSL and compared the disc foveal angle (DFA preoperatively and postoperatively. The split lengthening was done from 4 mm to 7 mm depending upon the overaction of superior oblique. Results: The mean age was 15.3 ± 8.4 years. Mean preoperative DFA in the right eye (RE was −3.9° and in the left eye (LE was −2.9°. Mean postoperative DFA in RE was 0.2° and in LE was 0.9°. The mean change in the DFA for RE was 4.1° ± 1.3° and for LE was 3.8° ± 1.2°. All the patients were aligned horizontally within 6 prism diopter and no pattern and no diplopia postoperatively. The A pattern was corrected in all the patient postsurgery. For each mm of surgery, an improvement of 0.8° was seen in the DFA. Conclusion: We report the effect of SOSL on torsion. The SOSL reduces intorsion postsurgery and is, therefore, a valuable procedure in SOOA where both pattern and in torsion needs to be corrected.

Optimal design of a magneto-rheological brake absorber for torsional vibration control

International Nuclear Information System (INIS)

Nguyen, Q H; Choi, S B

2012-01-01

This research presents an optimal design of a magneto-rheological (MR) brake absorber for torsional vibration control of a rotating shaft. Firstly, the configuration of an MR brake absorber for torsional vibration control of a rotating shaft system is proposed. Then, the braking torque of the MR brake is derived based on the Bingham plastic model of the MR fluid. By assuming that the behaviour of the MR brake absorber is similar to that of a dry friction torsional damper, the optimal braking torque to control the torsional vibration is determined and validated by simulation. The optimal design problem of the MR brake absorber is then developed and a procedure to solve the optimal problem is proposed. Based on the proposed optimal design procedure, the optimal design of a specific rotating shaft system is performed. Vibration control performance of the shaft system employing the optimized MR brake absorber is then investigated through simulation and discussion on the results is given. (paper)

Vertical bending strength and torsional rigidity analysis of formula student car chassis

Science.gov (United States)

Hazimi, Hashfi; Ubaidillah, Setiyawan, Adi Eka Putra; Ramdhani, Hanief Cahya; Saputra, Murnanda Zaesy; Imaduddin, Fitrian

2018-02-01

Formula Society of Automotive Engineers (FSAE) is a competition for students to construct formula student car. One of an essential part of a formula student car is its chassis. Chassis is an internal vehicle frame which holds all another part of the vehicle and secures the driver. The team have to design their chassis and tests their design to achieve the best chassis that fulfill the regulation. This paper contains chassis design from Bengawan FSAE Team and some FEA tests to find out the Tensile Strength, Torsional Rigidity, and Von Misses Stress of Formula SAE car. Torsional rigidity was found by applying the static torsional test. The results from torsional rigidity test are a maximum deformation of 9.9512 mm with 1.7064 safety factor, and 35.935 MPa maximum Von Misses Stress. Moreover, then the result of the vertical bending strength test is 8.1214 mm max deformation with safety factor 4.2717, and 29.226 MPa maximum Von Misses Stress.

Optimal design of a magneto-rheological brake absorber for torsional vibration control

Science.gov (United States)

Nguyen, Q. H.; Choi, S. B.

2012-02-01

This research presents an optimal design of a magneto-rheological (MR) brake absorber for torsional vibration control of a rotating shaft. Firstly, the configuration of an MR brake absorber for torsional vibration control of a rotating shaft system is proposed. Then, the braking torque of the MR brake is derived based on the Bingham plastic model of the MR fluid. By assuming that the behaviour of the MR brake absorber is similar to that of a dry friction torsional damper, the optimal braking torque to control the torsional vibration is determined and validated by simulation. The optimal design problem of the MR brake absorber is then developed and a procedure to solve the optimal problem is proposed. Based on the proposed optimal design procedure, the optimal design of a specific rotating shaft system is performed. Vibration control performance of the shaft system employing the optimized MR brake absorber is then investigated through simulation and discussion on the results is given.

Torsional surface waves in an inhomogeneous layer over a gravitating anisotropic porous half-space

International Nuclear Information System (INIS)

Gupta, Shishir; Pramanik, Abhijit

2015-01-01

The present work aims to deal with the propagation of torsional surface wave in an inhomogeneous layer over a gravitating anisotropic porous half space. The inhomogeneous layer exhibits the inhomogeneity of quadratic type. In order to show the effect of gravity the equation for the velocity of torsional wave has been obtained. It is also observed that for a layer over a homogeneous half space without gravity, the torsional surface wave does not propagate. An attempt is also made to assess the possible propagation of torsional surface waves in that medium in the absence of the upper layer. The effects of inhomogeneity factors and porosity on the phase velocity are depicted by means of graphs. (paper)

Torsion tensor and covector in a unified field theory

International Nuclear Information System (INIS)

Chernikov, N.A.

1976-01-01

The Einstein unified field theory is used to solve a tensor equation to provide the unambiguous definition of affine connectedness. In the process of solving the Einstein equation limitations imposed by symmetry on the tensor and the torsion covector as well as on affine connectedness are elucidated. It is demonstrated that in a symmetric case the connectedness is unambiguously determined by the Einstein equation. By means of the Riemann geometry a formula for the torsion covector is derived. The equivalence of Einstein equations to those of the nonlinear Born-Infeld electrodynamics is proved

Torsional Restraint Problem of Steel Cold-Formed Beams Restrained By Planar Members

Science.gov (United States)

Balázs, Ivan; Melcher, Jindřich; Pešek, Ondřej

2017-10-01

The effect of continuous or discrete lateral and torsional restraints of metal thinwalled members along their spans can positively influence their buckling resistance and thus contribute to more economical structural design. The prevention of displacement and rotation of the cross-section results in stabilization of the member. The restraints can practically be provided e.g. by planar members of cladding supported by metal members (purlins, girts). The rate of stabilization of a member can be quantified using values of shear and rotational stiffness provided by the adjacent planar members. While the lateral restraint effected by certain shear stiffness can be often considered as sufficient, the complete torsional restraint can be safely considered in some practical cases only. Otherwise the values of the appropriate rotational stiffness provided by adjacent planar members may not be satisfactory to ensure full torsional restraint and only incomplete restraint is available. Its verification should be performed using theoretical and experimental analyses. The paper focuses on problem of steel thin-walled coldformed beams stabilized by planar members and investigates the effect of the magnitude of the rotational stiffness provided by the planar members on the resistance of the steel members. Cold-formed steel beams supporting planar members of cladding are considered. Full lateral restraint and incomplete torsional restraint are assumed. Numerical analyses performed using a finite element method software indicate considerable influence of the torsional restraint on the buckling resistance of a steel thin-walled member. Utilization of the torsional restraint in the frame of sizing of a stabilized beam can result in more efficient structural design. The paper quantifies this effect for some selected cases and summarizes results of numerical analysis.

Success of torsional correction surgery after failed surgeries for patellofemoral pain and instability.

Science.gov (United States)

Stevens, Peter M; Gililland, Jeremy M; Anderson, Lucas A; Mickelson, Jennifer B; Nielson, Jenifer; Klatt, Joshua W

2014-04-01

Torsional deformities of the femur and/or tibia often go unrecognized in adolescents and adults who present with anterior knee pain, and patellar maltracking or instability. While open and arthroscopic surgical techniques have evolved to address these problems, unrecognized torsion may compromise the outcomes of these procedures. We collected a group of 16 consecutive patients (23 knees), with mean age of 17, who had undergone knee surgery before torsion was recognized and subsequently treated by means of rotational osteotomy of the tibia and/or femur. By follow-up questionnaire, we sought to determine the role of rotational correction at mean 59-month follow-up. We reasoned that, by correcting torsional alignment, we might be able to optimize long-term outcomes and avert repeated knee surgery. Knee pain was significantly improved after torsional treatment (mean 8.6 pre-op vs. 3.3 post-op, p instability, and 57 % could trust their knee after surgery. Activity level remained the same or increased in 78 % of patients after torsional treatment. Excluding planned rod removal, subsequent knee surgery for continued anterior knee pain was undertaken on only 3 knees in 2 patients. We believe that malrotation of the lower limb not only raises the propensity for anterior knee symptoms, but is also a under-recognized etiology in the failure of surgeries for anterior knee pain and patellar instability. Addressing rotational abnormalities in the index surgery yields better clinical outcomes than osteotomies performed after other prior knee surgeries.

Isolated torsion of fallopian tube. Radiological findings

International Nuclear Information System (INIS)

Tomas Fanjul, L.; Aldea Martinez, J.; Fernandez Matia, G.; Rodrigo Verguizas, J.; Fernandez Alvarez, G.; Galindo Vicente, M.C.

1993-01-01

Isolated tubal torsion is a very uncommon disorder that is rarely diagnosed preoperatively. We present a case and review the literature, which only provides ultrasonographic findings in 5 cases reported to date. 11 refs

Torsional and axial compressive properties of tibiotarsal bones of red-tailed hawks (Buteo jamaicensis).

Science.gov (United States)

Kerrigan, Shannon M; Kapatkin, Amy S; Garcia, Tanya C; Robinson, Duane A; Guzman, David Sanchez-Migallon; Stover, Susan M

2018-04-01

OBJECTIVE To describe the torsional and axial compressive properties of tibiotarsal bones of red-tailed hawks (Buteo jamaicensis). SAMPLE 16 cadaveric tibiotarsal bones from 8 red-tailed hawks. PROCEDURES 1 tibiotarsal bone from each bird was randomly assigned to be tested in torsion, and the contralateral bone was tested in axial compression. Intact bones were monotonically loaded in either torsion (n = 8) or axial compression (8) to failure. Mechanical variables were derived from load-deformation curves. Fracture configurations were described. Effects of sex, limb side, and bone dimensions on mechanical properties were assessed with a mixed-model ANOVA. Correlations between equivalent torsional and compressive properties were determined. RESULTS Limb side and bone dimensions were not associated with any mechanical property. During compression tests, mean ultimate cumulative energy and postyield energy for female bones were significantly greater than those for male bones. All 8 bones developed a spiral diaphyseal fracture and a metaphyseal fissure or fracture during torsional tests. During compression tests, all bones developed a crushed metaphysis and a fissure or comminuted fracture of the diaphysis. Positive correlations were apparent between most yield and ultimate torsional and compressive properties. CONCLUSIONS AND CLINICAL RELEVANCE The torsional and axial compressive properties of tibiotarsal bones described in this study can be used as a reference for investigations into fixation methods for tibiotarsal fractures in red-tailed hawks. Although the comminuted and spiral diaphyseal fractures induced in this study were consistent with those observed in clinical practice, the metaphyseal disruption observed was not and warrants further research.

Transverse vs torsional ultrasound: prospective randomized contralaterally controlled study comparing two phacoemulsification-system handpieces.

Science.gov (United States)

Assil, Kerry K; Harris, Lindsay; Cecka, Jeannie

2015-01-01

To compare surgical efficiency and multiple early clinical outcome variables in eyes undergoing phacoemulsification using either transversal or torsional ultrasound systems. Assil Eye Institute, Beverly Hills, CA, USA. Prospective, randomized, clinician-masked, contralaterally controlled single-center evaluation. Patients seeking cataract removal in both eyes with implantation of multifocal intraocular lenses were randomly assigned to one of two treatment rooms for phacoemulsification with either a transverse ultrasound system or torsional handpiece system. The contralateral eye was treated at a later date with the alternate device. A total of 54 eyes of 27 patients having similar degrees of cataract, astigmatism, and visual potential were included. All operative data were collected for analysis, and patients were followed for 3 months after surgery. Similar visual acuity was reported at all postoperative visits between the two groups. Mean phacoemulsification time and total power required were both significantly lower with the transverse system than with the torsional technique (Ptransverse system vs torsional (Ptransverse vs torsional. Macular swelling was less at 1 week, 1 month, and 3 months with transverse vs torsional, although the difference did not achieve significance (P=0.1) at any single time point. Clinically detectable corneal edema was reported less frequently at all postoperative time points with the transverse system. The transverse ultrasound system was found to be possibly associated with less balanced salt-solution use, less phacoemulsification time, and less power required than the torsional phaco system. Postoperative data suggested that improved phaco efficiency may translate to a better overall safety profile for the patient.

Fiber-Optic Sensors for Measurements of Torsion, Twist and Rotation: A Review

Directory of Open Access Journals (Sweden)

Vedran Budinski

2017-02-01

Full Text Available Optical measurement of mechanical parameters is gaining significant commercial interest in different industry sectors. Torsion, twist and rotation are among the very frequently measured mechanical parameters. Recently, twist/torsion/rotation sensors have become a topic of intense fiber-optic sensor research. Various sensing concepts have been reported. Many of those have different properties and performances, and many of them still need to be proven in out-of-the laboratory use. This paper provides an overview of basic approaches and a review of current state-of-the-art in fiber optic sensors for measurements of torsion, twist and/or rotation.Invited Paper

Development of a Meso-Scale Fiberoptic Rotation Sensor for a Torsion Actuator.

Science.gov (United States)

Sheng, Jun; Desai, Jaydev P

2018-01-01

This paper presents the development of a meso-scale fiberoptic rotation sensor for a shape memory alloy (SMA) torsion actuator for neurosurgical applications. Within the sensor, a rotary head with a reflecting surface is capable of modulating the light intensity collected by optical fibers when the rotary head is coupled to the torsion actuator. The mechanism of light intensity modulation is modeled, followed by experimental model verification. Meanwhile, working performances for different rotary head designs, optical fibers, and fabrication materials are compared. After the calibration of the fiberoptic rotation sensor, the sensor is capable of precisely measuring rotary motion and controlling the SMA torsion actuator with feedback control.

Torsional Moment Measurement on Bucket Wheel Shaft of Giant Machine

Directory of Open Access Journals (Sweden)

Jiří FRIES

2011-06-01

Full Text Available Bucket wheel loading at the present time (torsional moment on wheel shaft, peripheral cutting force is determined from electromotor incoming power or reaction force measured on gearbox hinge. Both methods together are weighted by steel construction absorption of driving units and by inertial forces of motor rotating parts. In the article is described direct method of the torsional moment measurement, which eliminates mentioned unfavourable impacts except absorption of steel construction of bucket wheel itself.

31 CFR 585.521 - Donations of food to relieve human suffering authorized.

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Donations of food to relieve human... Donations of food to relieve human suffering authorized. (a) Specific licenses may be issued on a case-by.... (b) In general, specific licenses will only be granted for donations of food to be provided through...

Step-edge calibration of torsional sensitivity for lateral force microscopy

International Nuclear Information System (INIS)

Sul, Onejae; Jang, Seongjin; Yang, Eui-Hyeok

2009-01-01

A novel calibration technique has been developed for lateral force microscopy (LFM). Typically, special preparation of the atomic force microscope (AFM) cantilever or a substrate is required for LFM calibration. The new calibration technique reported in this paper greatly reduces the required preparation processes by simply scanning over a rigid step and measuring the response of the AFM photodiode in the normal and lateral directions. When an AFM tip touches a step while scanning, the tip experiences a reaction force from the step edge, and the amount of torsion can be estimated based on the ratio of the normal and torsional spring constants of an AFM cantilever. Therefore, the torsion can be calibrated using the measured response of the photodiode from the lateral movement of the AFM tip. This new calibration technique has been tested and confirmed by measuring Young's modulus of a nickel (Ni) nanowire

Standing torsional waves in a fully saturated, porous, circular cylinder

CERN Document Server

Solorza, S; 10.1111/j.1365-246X.2004.02198.x

2004-01-01

For dynamic measurement of the elastic moduli of a porous material saturated with viscous fluid using the resonance-bar technique, one also observes attenuation. In this article we have carried out the solution of the boundary-value problem associated with standing torsional oscillations of a finite, poroelastic, circular cylinder cast in the framework of volume-averaged theory of poroelasticity. Analysing this solution by eigenvalue perturbation approach we are able to develop expressions for torsional resonance and temporal attenuation frequencies in which the dependence upon the material properties are transparent. It shows how the attenuation is controlled by the permeability and the fluid properties, and how the resonance frequency drops over its value for the dry solid-frame due to the drag effect of fluid mass. Based upon this work we have a firm basis to determine solid-frame shear modulus, permeability, and tortuosity factor from torsional oscillation experiments.

Lorentz violation bounds from torsion trace fermion sector and galaxy M51 data and chiral dynamos

Energy Technology Data Exchange (ETDEWEB)

Garcia de Andrade, L.C. [IF-UERJ, Departamento de Fisica Teorica, Rio de Janeiro, RJ (Brazil)

2017-06-15

Earlier we have computed a Lorentz violation (LV) bound for torsion terms via galactic dynamos and found bounds similar to the one obtained by Kostelecky et al. (Phys Rev Lett 100:111102, 2008) which is of the order of 10{sup -31} GeV. Their result was found making use of the axial torsion vector in terms of Dirac spinors and minimal torsion coupling in flat space-time of fermions. In this paper, a torsion dynamo equation obtained using the variation of the torsion trace and galaxy M51 data of 500 pc are used to place an upper bound of 10{sup -26} GeV in LV, which agrees with the one by Kostelecky and his group using an astrophysical framework background. Their lowest bound was obtained in earth laboratory using dual masers. One of the purposes of this paper is to apply the Faraday self-induction magnetic equation, recently extended to torsioned space-time, by the author to show that it lends support to physics in Riemann-Cartan space-time, in several distinct physical backgrounds. Backreaction magnetic effects are used to obtain the LV bounds. Previously Bamba et al. (JCAP 10:058, 2012) have used the torsion trace in their teleparallel investigation of the IGMF, with the argument that the torsion trace leads to less weaker effects than the other irreducible components of the torsion tensor. LV is computed in terms of a chiral-torsion-like current in the new dynamo equation analogous to the Dvornikov and Semikoz dynamo equation with chiral magnetic currents. Making use of the chiral-torsion dynamo equation we estimate the LV bounds in the early universe to be of the order of 10{sup -24} GeV, which was the order of the charged-lepton sector. Our main result is that it is possible to obtain more stringent bounds than the ones found in the fermion sector of astrophysics in the new revised 2017 data table for CPT and Lorentz violation by Kostelecky and Mewes. They found in several astrophysical backgrounds, orders of magnitude such as 10{sup -24} and 10{sup -23} Ge

Torsional, Vibrational and Vibration-Torsional Levels in the S_{1} and Ground Cationic D_{0}^{+} States of Para-Fluorotoluene

Science.gov (United States)

Gardner, Adrian M.; Tuttle, William Duncan; Whalley, Laura E.; Claydon, Andrew; Carter, Joseph H.; Wright, Timothy G.

2017-06-01

The S_{1} electronic state and ground state of the cation of para-fluorotoluene (pFT) have been investigated using resonance-enhanced multiphoton ionization (REMPI) spectroscopy and zero-kinetic-energy (ZEKE) spectroscopy. Here we focus on the low wavenumber region where a number of "pure" torsional, fundamental vibrational and vibration-torsional levels are expected; assignments of observed transitions are discussed, which are compared to results of published work on toluene (methylbenzene) from the Lawrance group. The similarity in the activity observed in the excitation spectrum of the two molecules is striking. A. M. Gardner, W. D. Tuttle, L. Whalley, A. Claydon, J. H. Carter and T. G. Wright, J. Chem. Phys., 145, 124307 (2016). J. R. Gascooke, E. A. Virgo, and W. D. Lawrance J. Chem. Phys., 143, 044313 (2015).

Torsion of the central pair microtubules in eukaryotic flagella due to bending-driven lateral buckling

International Nuclear Information System (INIS)

Li, C.; Ru, C.Q.; Mioduchowski, A.

2006-01-01

Inspired by recent interest in torsion of the central pair microtubules in eukaryotic flagella, a novel thin-walled elastic beam model is suggested to study critical condition under which uniform bending of a flagellum will cause lateral/torsional buckling of the central pair. The model is directed to the central pair itself and the role of all surrounding cross-linkings inside the flagellum is modeled as an equivalent surrounding elastic medium. The model predicts that bending-driven torsion of the central pair does occur when the radius of curvature of the bent flagellum reduces to a moderate critical value typically of tens of microns. In particular, this critical value is almost independent of the flagellum length, and more sensitive to the parameters defining the surrounding elastic medium than the shear modulus of microtubules. The predicted wavelengths of the torsional buckling mode are insensitive to the flagellum length and comparable to some known related experimental data. These results indicate that torsion of the central pair microtubules in flagella is inevitable as a result of bending-driven lateral buckling. This offers an entirely new insight into the ongoing research on the mechanism of the central pair torsion

Torsion of a nongravid uterus with a large ovarian cyst: usefulness of contrast MR image.

Science.gov (United States)

Matsumoto, Hiroki; Ohta, Tsuyoshi; Nakahara, Kenji; Kojimahara, Takanobu; Kurachi, Hirohisa

2007-01-01

Torsion of a nongravid uterus is extremely rare. Most cases of uterine torsion occur during pregnancy. Here we report a case of nongravid uterus torsion with a large adnexal mass. A 73-year-old woman presented at the emergency room with acute abdominal pain. A preoperative diagnosis of torsion of an ovarian cyst was made and laparotomy was performed. The left ovary was twisted 360 degrees in a clockwise rotation, and the uterine corpus had also undergone a 360 degrees rotation. Total abdominal hysterectomy and bilateral salpingo-oophorectomy were carried out. Although a preoperative diagnosis of uterine torsion was not possible, it is noteworthy that in the contrast-enhanced magnetic resonance images the uterine cervix was intensely enhanced, while the uterine corpus was not. This is the first report to show the magnetic resonance imaging findings of a twisted uterus. Copyright (c) 2007 S. Karger AG, Basel.

Torsional Performance of Wind Turbine Blades

DEFF Research Database (Denmark)

Branner, Kim; Berring, Peter; Berggreen, Christian

2007-01-01

The present work investigates how well different finite element modeling techniques can predict bending and torsion behavior of a wind turbine blade. Two shell models are investigated. One model has element offsets and the other has the elements at the mid-thickness surfaces of the model. The las...

Weakly dynamic dark energy via metric-scalar couplings with torsion

Energy Technology Data Exchange (ETDEWEB)

Sur, Sourav; Bhatia, Arshdeep Singh, E-mail: sourav.sur@gmail.com, E-mail: arshdeepsb@gmail.com [Department of Physics and Astrophysics, University of Delhi, New Delhi, 110 007 (India)

2017-07-01

We study the dynamical aspects of dark energy in the context of a non-minimally coupled scalar field with curvature and torsion. Whereas the scalar field acts as the source of the trace mode of torsion, a suitable constraint on the torsion pseudo-trace provides a mass term for the scalar field in the effective action. In the equivalent scalar-tensor framework, we find explicit cosmological solutions representing dark energy in both Einstein and Jordan frames. We demand the dynamical evolution of the dark energy to be weak enough, so that the present-day values of the cosmological parameters could be estimated keeping them within the confidence limits set for the standard LCDM model from recent observations. For such estimates, we examine the variations of the effective matter density and the dark energy equation of state parameters over different redshift ranges. In spite of being weakly dynamic, the dark energy component differs significantly from the cosmological constant, both in characteristics and features, for e.g. it interacts with the cosmological (dust) fluid in the Einstein frame, and crosses the phantom barrier in the Jordan frame. We also obtain the upper bounds on the torsion mode parameters and the lower bound on the effective Brans-Dicke parameter. The latter turns out to be fairly large, and in agreement with the local gravity constraints, which therefore come in support of our analysis.

Hardening and softening mechanisms of pearlitic steel wire under torsion

International Nuclear Information System (INIS)

Zhao, Tian-Zhang; Zhang, Shi-Hong; Zhang, Guang-Liang; Song, Hong-Wu; Cheng, Ming

2014-01-01

Highlights: • Mechanical behavior of pearlitic steel wire is studied using torsion. • Work hardening results from refinement lamellar pearlitic structure. • Softening results from recovery, shear bands and lamellar fragmentations. • A microstructure based analytical flow stress model is established. - Abstract: The mechanical behaviors and microstructure evolution of pearlitic steel wires under monotonic shear deformation have been investigated by a torsion test and a number of electron microscopy techniques including scanning electron microscopy (SEM) and transmission electron microscopy (TEM), with an aim to reveal the softening and hardening mechanisms of a randomly oriented pearlitic structure during a monotonic stain path. Significantly different from the remarkable strain hardening in cold wire drawing, the strain hardening rate during torsion drops to zero quickly after a short hardening stage. The microstructure observations indicate that the inter-lamellar spacing (ILS) decreases and the dislocations accumulate with strain, which leads to hardening of the material. Meanwhile, when the strain is larger than 0.154, the enhancement of dynamic recovery, shear bands (SBs) and cementite fragmentations results in the softening and balances the strain hardening. A microstructure based analytical flow stress model with considering the influence of ILS on the mean free path of dislocations and the softening caused by SBs and cementite fragmentations, has been established and the predicted flow shear curve meets well with the measured curve in the torsion test

Scalar-metric and scalar-metric-torsion gravitational theories

International Nuclear Information System (INIS)

Aldersley, S.J.

1977-01-01

The techniques of dimensional analysis and of the theory of tensorial concomitants are employed to study field equations in gravitational theories which incorporate scalar fields of the Brans-Dicke type. Within the context of scalar-metric gravitational theories, a uniqueness theorem for the geometric (or gravitational) part of the field equations is proven and a Lagrangian is determined which is uniquely specified by dimensional analysis. Within the context of scalar-metric-torsion gravitational theories a uniqueness theorem for field Lagrangians is presented and the corresponding Euler-Lagrange equations are given. Finally, an example of a scalar-metric-torsion theory is presented which is similar in many respects to the Brans-Dicke theory and the Einstein-Cartan theory

Toward laboratory torsional spine magnetic reconnection

Science.gov (United States)

Chesny, David L.; Orange, N. Brice; Oluseyi, Hakeem M.; Valletta, David R.

2017-12-01

Magnetic reconnection is a fundamental energy conversion mechanism in nature. Major attempts to study this process in controlled settings on Earth have largely been limited to reproducing approximately two-dimensional (2-D) reconnection dynamics. Other experiments describing reconnection near three-dimensional null points are non-driven, and do not induce any of the 3-D modes of spine fan, torsional fan or torsional spine reconnection. In order to study these important 3-D modes observed in astrophysical plasmas (e.g. the solar atmosphere), laboratory set-ups must be designed to induce driven reconnection about an isolated magnetic null point. As such, we consider the limited range of fundamental resistive magnetohydrodynamic (MHD) and kinetic parameters of dynamic laboratory plasmas that are necessary to induce the torsional spine reconnection (TSR) mode characterized by a driven rotational slippage of field lines - a feature that has yet to be achieved in operational laboratory magnetic reconnection experiments. Leveraging existing reconnection models, we show that within a 3$ apparatus, TSR can be achieved in dense plasma regimes ( 24~\\text{m}-3$ ) in magnetic fields of -1~\\text{T}$ . We find that MHD and kinetic parameters predict reconnection in thin current sheets on time scales of . While these plasma regimes may not explicitly replicate the plasma parameters of observed astrophysical phenomena, studying the dynamics of the TSR mode within achievable set-ups signifies an important step in understanding the fundamentals of driven 3-D magnetic reconnection and the self-organization of current sheets. Explicit control of this reconnection mode may have implications for understanding particle acceleration in astrophysical environments, and may even have practical applications to fields such as spacecraft propulsion.

Torsional vibration of crankshaft in an engine propeller nonlinear dynamical system

Science.gov (United States)

Zhang, X.; Yu, S. D.

2009-01-01

Theoretical and experimental studies on torsional vibration of an aircraft engine-propeller system are presented in this paper. Two system models—a rigid body model and a flexible body model, are developed for predicting torsional vibrations of the crankshaft under different engine powers and propeller pitch settings. In the flexible body model, the distributed torsional flexibility and mass moment of inertia of the crankshaft are considered using the finite element method. The nonlinear autonomous equations of motion for the engine-propeller dynamical system are established using the augmented Lagrange equations, and solved using the Runge-Kutta method after a degrees of freedom reduction scheme is applied. Experiments are carried out on a three-cylinder four-stroke engine. Both theoretical and experimental studies reveal that the crankshaft flexibility has significant influence on the system dynamical behavior.

Torsional vibration of a pipe pile in transversely isotropic saturated soil

Science.gov (United States)

Zheng, Changjie; Hua, Jianmin; Ding, Xuanming

2016-09-01

This study considers the torsional vibration of a pipe pile in a transversely isotropic saturated soil layer. Based on Biot's poroelastic theory and the constitutive relations of the transversely isotropic medium, the dynamic governing equations of the outer and inner transversely isotropic saturated soil layers are derived. The Laplace transform is used to solve the governing equations of the outer and inner soil layers. The dynamic torsional response of the pipe pile in the frequency domain is derived utilizing 1D elastic theory and the continuous conditions at the interfaces between the pipe pile and the soils. The time domain solution is obtained by Fourier inverse transform. A parametric study is conducted to demonstrate the influence of the anisotropies of the outer and inner soil on the torsional dynamic response of the pipe pile.

[Posttraumatic torsional deformities of the forearm : Methods of measurement and decision guidelines for correction].

Science.gov (United States)

Blossey, R D; Krettek, C; Liodakis, E

2018-03-01

Forearm fractures are common in all age groups. Even if the adjacent joints are not directly involved, these fractures have an intra-articular character. One of the most common complications of these injuries is a painful limitation of the range of motion and especially of pronation and supination. This is often due to an underdiagnosed torsional deformity; however, in recent years new methods have been developed to make these torsional differences visible and quantifiable through the use of sectional imaging. The principle of measurement corresponds to that of the torsion measurement of the lower limbs. Computed tomography (CT) or magnetic resonance imaging (MRI) scans are created at defined heights. By searching for certain landmarks, torsional angles are measured in relation to a defined reference line. A new alternative is the use of 3D reformation models. The presence of a torsional deformity, especial of the radius, leads to an impairment of the pronation and supination of the forearm. In the presence of torsional deformities, radiological measurements can help to decide if an operation is needed or not. Unlike the lower limbs, there are still no uniform cut-off values as to when a correction is indicated. Decisions must be made together with the patient by taking the clinical and radiological results into account.

Relieving idiopathic dental pain without drugs

Directory of Open Access Journals (Sweden)

Haryono Utomo

2011-06-01

Full Text Available Background: Teeth are commonly obvious source of orofacial pain. Sometimes the pain source is undetectable, thus called as idiopathic dental pain. Since dentist wants to alleviate or eliminate the pains with every effort in their mind, a lot of drugs could be prescribed. Moreover, it is make sense that endodontic treatment or even tooth extraction will be done. Unfortunately, endodontic treatment may also initiate neuropathic tooth pain that is caused by nerve extirpation, thus worsen the pain. Therefore, another cause of dental pain such as referred pain, periodontal disease, or stress which related to psychoneuroimmunology should be considered. In order to prevent from unnecessary drugs or invasive treatment such as root canal treatment and extraction, correct diagnosis and preliminary non-invasive therapies should be done. Purpose: This review elucidates several therapies that could be done by dentists for relieving idiopathic dental pain which includes massage, the “assisted drainage” therapy, modulation of psychoneuroimmunologic status and dietary omega-3. Reviews: Understanding the basic pathogenesis of pain may help in elucidating the effects of non-drug pain therapy such as muscle massage, the “assisted drainage” therapy, omega-3 and psychological stress relieving. These measures are accounted for eliminating referred pain, reducing proinflammatory mediators and relieving unwanted stress reactions consecutively. Psychological stress increases proinflammatory cytokines and thus lowered pain threshold. Conclusion: As an individual treatment, this non-drug therapy is useful in relieving idiopathic dental pain; nevertheless, if they work together the result could be more superior.Latar belakang: Gigi adalah suatu penyebab umum dari nyeri orofasial. Kadang kala penyebab nyeri tidak dapat ditemukan, sehingga disebut sebagai nyeri gigi idiopatik. Karena dokter gigi berupaya untuk mengurangi atau menghilangkan nyeri dengan segala cara

DNA oligonucleotide conformations: high resolution NMR studies

International Nuclear Information System (INIS)

Mellema, J.-R.

1984-01-01

The present work describes a DNA double-helix model, which is well comparable with the models derived from fibre-diffraction studies. The model has a mononucleotide repeat with torsion angles in accordance with average geometries as derived from 1 H NMR studies. Special attention was paid to reduce the number of short H-H nonbonding contacts, which are abundantly present in the 'classical' fibre-diffraction models. Chapter 3 describes the first complete assignment of a 1 H NMR spectrum of a DNA tetramer, d(TAAT). Preliminary conformational data derived from the spectral parameters recorded at 27 0 C are given. A more detailed analysis employing temperature-dependence studies is given in Chapter 4. (Auth.)

Bifurcations and chaos of DNA solitonic dynamics

International Nuclear Information System (INIS)

Gonzalez, J.A.; Martin-Landrove, M.; Carbo, J.R.; Chacon, M.

1994-09-01

We investigated the nonlinear DNA torsional equations proposed by Yakushevich in the presence of damping and external torques. Analytical expressions for some solutions are obtained in the case of the isolated chain. Special attention is paid to the stability of the solutions and the range of soliton interaction in the general case. The bifurcation analysis is performed and prediction of chaos is obtained for some set of parameters. Some biological implications are suggested. (author). 11 refs, 13 figs

Dynamics of the central phenylene ring torsional motion in halogenated phenylene ethynylene oligomers

Energy Technology Data Exchange (ETDEWEB)

Pejov, Ljupco [Institute of Chemistry, Department of Physical Chemistry, SS. Cyril and Methodius University, Arhimedova 5, P.O. Box 162, 1000 Skopje(Macedonia, The Former Yugoslav Republic of)], E-mail: ljupcop@iunona.pmf.ukim.edu.mk; La Rosa, Manuela [PST Group- M6, STMicroelectronics, Stradale Primosole 50, 95121 Catania (Italy); Kocarev, Ljupco [Institute for Nonlinear Science, University of California, San Diego 9500 Gilman, Drive, La Jolla, CA 92093-0402 (United States); Macedonian Academy of Sciences and Arts, bul. Krste Misirkov 2, P.O. Box 428, 1000 Skopje (Macedonia, The Former Yugoslav Republic of)

2007-11-09

The dynamics of intramolecular torsional motion of central phenylene ring in a series of phenylene ethynylene oligomer derivatives was investigated. On the basis of calculated hindered rotational potentials corresponding to this motion, the torsional energy levels were obtained by solving the torsional Schroedinger equation. Subsequently, the torsional correlation time and transition probability was computed within the Bloembergen-Purcell-Pound (BPP) formalism, considering both the classical and quantum mechanical tunneling contributions to the intramolecular rotation. The results were interpreted in the context of molecular conductivity switching behavior of the considered series of compounds. Also some other parameters relevant to molecular admittance were calculated, such as the HOMO-LUMO energy difference and the spatial extent of the frontier molecular orbitals. Classical electrostatic arguments were applied to understand the physical basis of the conformational stability differences in the studied compounds. It was found that halogenation of the central phenylene ring may be used for fine-tuning of molecular conduction behavior, in the sense of modulating the HOMO-LUMO energy difference, the spatial extent of frontier MOs, as well as the barrier height to torsional motion of the central phenylene ring. The time scale of the temperature induced stochastic conformational switching between the 'on' and 'off' states, along with the corresponding transition probability could be varied by an order of magnitude upon halogenation of the central phenylene ring. The tunneling contributions to the torsional correlation time were found to be of minor importance in this context, and this quantity may be quite correctly estimated with the classical BPP approach.

Dynamics of the central phenylene ring torsional motion in halogenated phenylene ethynylene oligomers

International Nuclear Information System (INIS)

Pejov, Ljupco; La Rosa, Manuela; Kocarev, Ljupco

2007-01-01

The dynamics of intramolecular torsional motion of central phenylene ring in a series of phenylene ethynylene oligomer derivatives was investigated. On the basis of calculated hindered rotational potentials corresponding to this motion, the torsional energy levels were obtained by solving the torsional Schroedinger equation. Subsequently, the torsional correlation time and transition probability was computed within the Bloembergen-Purcell-Pound (BPP) formalism, considering both the classical and quantum mechanical tunneling contributions to the intramolecular rotation. The results were interpreted in the context of molecular conductivity switching behavior of the considered series of compounds. Also some other parameters relevant to molecular admittance were calculated, such as the HOMO-LUMO energy difference and the spatial extent of the frontier molecular orbitals. Classical electrostatic arguments were applied to understand the physical basis of the conformational stability differences in the studied compounds. It was found that halogenation of the central phenylene ring may be used for fine-tuning of molecular conduction behavior, in the sense of modulating the HOMO-LUMO energy difference, the spatial extent of frontier MOs, as well as the barrier height to torsional motion of the central phenylene ring. The time scale of the temperature induced stochastic conformational switching between the 'on' and 'off' states, along with the corresponding transition probability could be varied by an order of magnitude upon halogenation of the central phenylene ring. The tunneling contributions to the torsional correlation time were found to be of minor importance in this context, and this quantity may be quite correctly estimated with the classical BPP approach

Spacetime thermodynamics in the presence of torsion

Science.gov (United States)

Dey, Ramit; Liberati, Stefano; Pranzetti, Daniele

2017-12-01

It was shown by Jacobson in 1995 that the Einstein equation can be derived as a local constitutive equation for an equilibrium spacetime thermodynamics. With the aim to understand if such thermodynamical description is an intrinsic property of gravitation, many attempts have been made so far to generalize this treatment to a broader class of gravitational theories. Here we consider the case of the Einstein-Cartan theory as a prototype of theories with nonpropagating torsion. In doing so, we study the properties of Killing horizons in the presence of torsion, establish the notion of local causal horizon in Riemann-Cartan spacetimes, and derive the generalized Raychaudhuri equation for these kinds of geometries. Then, starting with the entropy that can be associated to these local causal horizons, we derive the Einstein-Cartan equation by implementing the Clausius equation. We outline two ways of proceeding with the derivation depending on whether we take torsion as a geometric field or as a matter field. In both cases we need to add internal entropy production terms to the Clausius equation as the shear and twist cannot be taken to be 0 a priori for our setup. This fact implies the necessity of a nonequilibrium thermodynamics treatment for the local causal horizon. Furthermore, it implies that a nonzero twist at the horizon in general contributes to the Hartle-Hawking tidal heating for black holes with possible implications for future observations.

Electrostatically actuated torsional resonant sensors and switches

KAUST Repository

Younis, Mohammad I.

2016-01-01

Embodiments in accordance of a torsional resonant sensor disclosure is configured to actuate a beam structure using electrostatic actuation with an AC harmonic load (e.g., AC and DC voltage sources) that is activated upon detecting a particular

Molecular dynamics simulation on the elastoplastic properties of copper nanowire under torsion

Science.gov (United States)

Yang, Yong; Li, Ying; Yang, Zailin; Zhang, Guowei; Wang, Xizhi; Liu, Jin

2018-02-01

Influences of different factors on the torsion properties of single crystal copper nanowire are studied by molecular dynamics method. The length, torsional rate, and temperature of the nanowire are discussed at the elastic-plastic critical point. According to the average potential energy curve and shear stress curve, the elastic-plastic critical angle is determined. Also, the dislocation at elastoplastic critical points is analyzed. The simulation results show that the single crystal copper nanowire can be strengthened by lengthening the model, decreasing the torsional rate, and lowering the temperature. Moreover, atoms move violently and dislocation is more likely to occur with a higher temperature. This work mainly describes the mechanical behavior of the model under different states.

All-solid-state carbon nanotube torsional and tensile artificial muscles.

Science.gov (United States)

Lee, Jae Ah; Kim, Youn Tae; Spinks, Geoffrey M; Suh, Dongseok; Lepró, Xavier; Lima, Mácio D; Baughman, Ray H; Kim, Seon Jeong

2014-05-14

We report electrochemically powered, all-solid-state torsional and tensile artificial yarn muscles using a spinnable carbon nanotube (CNT) sheet that provides attractive performance. Large torsional muscle stroke (53°/mm) with minor hysteresis loop was obtained for a low applied voltage (5 V) without the use of a relatively complex three-electrode electromechanical setup, liquid electrolyte, or packaging. Useful tensile muscle strokes were obtained (1.3% at 2.5 V and 0.52% at 1 V) when lifting loads that are ∼25 times heavier than can be lifted by the same diameter human skeletal muscle. Also, the tensile actuator maintained its contraction following charging and subsequent disconnection from the power supply because of its own supercapacitor property at the same time. Possible eventual applications for the individual tensile and torsional muscles are in micromechanical devices, such as for controlling valves and stirring liquids in microfluidic circuits, and in medical catheters.

Review of gastric torsion in eight guinea pigs (Cavia porcellus).

Science.gov (United States)

Nógrádi, Anna Linda; Cope, Iain; Balogh, Márton; Gál, János

2017-12-01

The authors present eight cases of gastric dilatation and volvulus (GDV) in guinea pigs from the Department and Clinic of Exotic Animal and Wildlife Medicine, University of Veterinary Medicine, Budapest, Hungary between 2012 and 2016. Seven animals were operated on and two survived. Gastric torsion has been noted in many mammalian species. Gastric volvulus has a high morbidity and high mortality rate with a guarded to poor prognosis in all of these species. How GDV develops is still not widely understood. Postmortem examinations, in both our cases and previously reported cases, have failed to reveal the exact causes of the gastric torsions. The aetiology of gastric torsion in guinea pigs is probably multifactorial. Feeding fewer meals per day, eating rapidly, decreased food particle size, exercise, stress after a meal, competition, age, and an aggressive or fearful temperament, are all likely and potential risk factors for GDV development in a similar fashion to dogs. Sex, breeding, dental diseases, anatomical abnormalities, pain and pregnancy may also be contributing factors.

Fiber-Optic Sensors for Measurements of Torsion, Twist and Rotation: A Review †

Science.gov (United States)

Budinski, Vedran; Donlagic, Denis

2017-01-01

Optical measurement of mechanical parameters is gaining significant commercial interest in different industry sectors. Torsion, twist and rotation are among the very frequently measured mechanical parameters. Recently, twist/torsion/rotation sensors have become a topic of intense fiber-optic sensor research. Various sensing concepts have been reported. Many of those have different properties and performances, and many of them still need to be proven in out-of-the laboratory use. This paper provides an overview of basic approaches and a review of current state-of-the-art in fiber optic sensors for measurements of torsion, twist and/or rotation. PMID:28241510

Torsion pendulum for the performance test of the inertial sensor for ASTROD-I

International Nuclear Information System (INIS)

Zhou, Z B; Gao, S W; Luo, J

2005-01-01

A torsion pendulum facility for a ground-based performance test of the inertial sensor for ASTROD-1 has been constructed. The twist motion of the test mass is monitored and servo-controlled. The sensitivity of the electrostatic servo-controlled actuator is calibrated based on the elastic torque of the torsion fibre, and the torque resolution of the servo-controlled torsion pendulum comes to 2 x 10 -11 N m Hz -1/2 from 1 mHz to 0.1 Hz, which is likely limited by the seismic noise, electronic noise and the cross coupling between the translation and twist modes

How Can I Relieve My Pregnancy Leg Cramps?

Science.gov (United States)

... Fitness Diseases & Conditions Infections Drugs & Alcohol School & Jobs Sports Expert Answers (Q&A) Staying Safe Videos for Educators Search English Español How Can I Relieve My Pregnancy Leg Cramps? KidsHealth / For Parents / How Can I ...

Proposal for quantum many-body simulation and torsional matter-wave interferometry with a levitated nanodiamond

Science.gov (United States)

Ma, Yue; Hoang, Thai M.; Gong, Ming; Li, Tongcang; Yin, Zhang-qi

2017-08-01

Hybrid spin-mechanical systems have great potential in sensing, macroscopic quantum mechanics, and quantum information science. In order to induce strong coupling between an electron spin and the center-of-mass motion of a mechanical oscillator, a large magnetic gradient usually is required, which is difficult to achieve. Here we show that strong coupling between the electron spin of a nitrogen-vacancy (NV) center and the torsional vibration of an optically levitated nanodiamond can be achieved in a uniform magnetic field. Thanks to the uniform magnetic field, multiple spins can strongly couple to the torsional vibration at the same time. We propose utilizing this coupling mechanism to realize the Lipkin-Meshkov-Glick (LMG) model by an ensemble of NV centers in a levitated nanodiamond. The quantum phase transition in the LMG model and finite number effects can be observed with this system. We also propose generating torsional superposition states and realizing torsional matter-wave interferometry with spin-torsional coupling.

A 2-DOF microstructure-dependent model for the coupled torsion/bending instability of rotational nanoscanner

Science.gov (United States)

Keivani, M.; Abadian, N.; Koochi, A.; Mokhtari, J.; Abadyan, M.

2016-10-01

It has been well established that the physical performance of nanodevices might be affected by the microstructure. Herein, a two-degree-of-freedom model base on the modified couple stress theory is developed to incorporate the impact of microstructure in the torsion/bending coupled instability of rotational nanoscanner. Effect of microstructure dependency on the instability parameters is determined as a function of the microstructure parameter, bending/torsion coupling ratio, van der Waals force parameter and geometrical dimensions. It is found that the bending/torsion coupling substantially affects the stable behavior of the scanners especially those with long rotational beam elements. Impact of microstructure on instability voltage of the nanoscanner depends on coupling ratio and the conquering bending mode over torsion mode. This effect is more highlighted for higher values of coupling ratio. Depending on the geometry and material characteristics, the presented model is able to simulate both hardening behavior (due to microstructure) and softening behavior (due to torsion/bending coupling) of the nanoscanners.

Torsion zero-cycles and the Abel-Jacobi map over the real numbers

NARCIS (Netherlands)

Hamel, J. van

1999-01-01

This is a study of the torsion in the Chow group of zero-cycles on a variety over the real numbers. The first section recalls important results from the literature. The rest of the paper is devoted to the study of the Abel–Jacobi map a: A0XAlbXR restricted to torsion subgroups. Using Roitman’s

Theory of pure rotational transitions in doubly degenerate torsional states of ethane

Science.gov (United States)

Rosenberg, A.; Susskind, J.

1979-01-01

It is shown that pure rotational transitions in doubly degenerate torsional states of C2H6 (with selection rules Delta K = 0, plus or minus 1) are made allowed by Coriolis interaction between torsion and dipole-allowed vibrations. Expressions are presented for integrated intensities from which strengths of lines in the millimeter region can be calculated.

A STUDY ON TIBIAL TORSION IN ADULT DRY TIBIA OF EAST AND SOUTH INDIAN POPULATION

Directory of Open Access Journals (Sweden)

Jami Sagar Prusti

2017-05-01

Full Text Available BACKGROUND Rotational deformities of the lower limbs are very common. There is increasing evidence that abnormal torsion in the tibia is associated with severe knee and ankle arthritis. Primary knee osteoarthritis is a leading cause of disability in older persons. Varus or valgus alignment increases the risk of osteoarthritis. Coexistence of tibial torsional deformity may increase the risk further. Variability in the tibial torsion has been reported and is due to the torsional forces applied on tibia during development. The aim of the study is to estimate the angle of tibial torsion on both sides and both sexes. The present study was an attempt to provide baseline data of tibial torsion in the East and South Indian population. MATERIALS AND METHODS The study was conducted mechanically on 100 dry adult unpaired human tibia, i.e. 50 male and 50 female bones. The measurements were recorded and statistically analysed using Student’s unpaired t-test using GraphPad Prism 5.0 (free trial version. RESULTS Out of the 100 tibia undertaken, mean value of tibial torsion angle obtained is 25.8°. In males, it is 23.68° and in females it is about 27.86°. Statistical analysis revealed significant greater average angle of tibial torsion in female bones. The angle of the right-sided bones was more and this was statistically significant. CONCLUSION The gender variation for the angle could be the result of the difference in lifestyle in day-to-day activities. The knowledge of the angle in a population could be helpful in understanding the incidence of pathogenesis related to gait and knee osteoarthritis and in view of reconstructive surgeries in orthopaedic practice.

Sporadic adult onset primary torsion dystonia is a genetic disorder by the temporal discrimination test.

LENUS (Irish Health Repository)

Kimmich, Okka

2012-02-01

Adult-onset primary torsion dystonia is an autosomal dominant disorder with markedly reduced penetrance; patients with sporadic adult-onset primary torsion dystonia are much more prevalent than familial. The temporal discrimination threshold is the shortest time interval at which two stimuli are detected to be asynchronous and has been shown to be abnormal in adult-onset primary torsion dystonia. The aim was to determine the frequency of abnormal temporal discrimination thresholds in patients with sporadic adult-onset primary torsion dystonia and their first-degree relatives. We hypothesized that abnormal temporal discrimination thresholds in first relatives would be compatible with an autosomal dominant endophenotype. Temporal discrimination thresholds were examined in 61 control subjects (39 subjects <50 years of age; 22 subjects >50 years of age), 32 patients with sporadic adult-onset primary torsion dystonia (cervical dystonia n = 30, spasmodic dysphonia n = 1 and Meige\\'s syndrome n = 1) and 73 unaffected first-degree relatives (36 siblings, 36 offspring and one parent) using visual and tactile stimuli. Z-scores were calculated for all subjects; a Z > 2.5 was considered abnormal. Abnormal temporal discrimination thresholds were found in 1\\/61 (2%) control subjects, 27\\/32 (84%) patients with adult-onset primary torsion dystonia and 32\\/73 (44%) unaffected relatives [siblings (20\\/36; 56%), offspring (11\\/36; 31%) and one parent]. When two or more relatives were tested in any one family, 22 of 24 families had at least one first-degree relative with an abnormal temporal discrimination threshold. The frequency of abnormal temporal discrimination thresholds in first-degree relatives of patients with sporadic adult-onset primary torsion dystonia is compatible with an autosomal dominant disorder and supports the hypothesis that apparently sporadic adult-onset primary torsion dystonia is genetic in origin.

Sporadic adult onset primary torsion dystonia is a genetic disorder by the temporal discrimination test.

Science.gov (United States)

Kimmich, Okka; Bradley, David; Whelan, Robert; Mulrooney, Nicola; Reilly, Richard B; Hutchinson, Siobhan; O'Riordan, Sean; Hutchinson, Michael

2011-09-01

Adult-onset primary torsion dystonia is an autosomal dominant disorder with markedly reduced penetrance; patients with sporadic adult-onset primary torsion dystonia are much more prevalent than familial. The temporal discrimination threshold is the shortest time interval at which two stimuli are detected to be asynchronous and has been shown to be abnormal in adult-onset primary torsion dystonia. The aim was to determine the frequency of abnormal temporal discrimination thresholds in patients with sporadic adult-onset primary torsion dystonia and their first-degree relatives. We hypothesized that abnormal temporal discrimination thresholds in first relatives would be compatible with an autosomal dominant endophenotype. Temporal discrimination thresholds were examined in 61 control subjects (39 subjects 50 years of age), 32 patients with sporadic adult-onset primary torsion dystonia (cervical dystonia n = 30, spasmodic dysphonia n = 1 and Meige's syndrome n = 1) and 73 unaffected first-degree relatives (36 siblings, 36 offspring and one parent) using visual and tactile stimuli. Z-scores were calculated for all subjects; a Z > 2.5 was considered abnormal. Abnormal temporal discrimination thresholds were found in 1/61 (2%) control subjects, 27/32 (84%) patients with adult-onset primary torsion dystonia and 32/73 (44%) unaffected relatives [siblings (20/36; 56%), offspring (11/36; 31%) and one parent]. When two or more relatives were tested in any one family, 22 of 24 families had at least one first-degree relative with an abnormal temporal discrimination threshold. The frequency of abnormal temporal discrimination thresholds in first-degree relatives of patients with sporadic adult-onset primary torsion dystonia is compatible with an autosomal dominant disorder and supports the hypothesis that apparently sporadic adult-onset primary torsion dystonia is genetic in origin.

Increase of resistance to cracking on stress relieving of hardened steel

International Nuclear Information System (INIS)

Velichko, V.V.; Zabil'skij, V.V.; Mikheev, G.M.

1995-01-01

Regularities of increase of resistance to cracking during stress relieving of hardened low-alloyed steels were studied, using complex of methods. Effect of carbon, stress concentrator radius, duration and temperature of stress relieving was studies in particular. Results of investigating kinetics of change of physicomechanical properties, hydrogen desorption from hardened specimens showed, that increase of resistance to cracking was caused by desorption from grain boundaries of diffusion-mobile hydrogen, formed during hardening. 18 refs., 8 figs

Exact interior solutions for static spheres in the Einstein-Cartan theory with two sources of torsion

CERN Document Server

Gallakhmetov, A M

2002-01-01

In the framework of the problem of existence of exact interior solutions for static spherically symmetric configurations in the Einstein-Cartan theory (ECT), the distributions of perfect fluid and non-minimally coupled scalar field are considered. The exact solutions in the one-torsion ECT and two-torsion one are obtained. Some consequences of two sources of torsion are discussed.

Aberrant femoral torsion presenting with frog-leg squatting mimicking gluteal muscle contracture.

Science.gov (United States)

Chiang, Chia-Ling; Tsai, Meng-Yuan; Chang, Wei-Ning; Chen, Clement Kuen-Huang

2012-04-01

Patients with frog-leg squatting have restricted internal rotation and adduction of the affected hips during sitting or squatting. In the surgical literature, the cause generally has been presumed to arise from and be pathognomonic for gluteal muscle contracture. However, we have encountered patients with frog-leg squatting but without gluteal muscle contracture. We therefore raised the following questions: What are the imaging features of patients with frog-leg squatting? Do conditions other than gluteal muscle contracture manifest frog-leg squatting? We retrospectively reviewed the MR images of 67 patients presenting with frog-leg squatting from April 1998 to July 2010. There were four females and 63 males; their mean age was 22.2 years (range, 4-50 years). During MRI readout, we observed aberrant axes of some femoral necks and obtained additional CT to measure femoral torsion angles in 59 of the 67 patients. MR images of 27 (40%) patients had signs of gluteal muscle contracture. Twenty-two (33%) patients (40 femora) had aberrant femoral torsion, including diminished anteversion (range, 6°-0°; average, 3.9°) in 11 femora of eight patients and femoral retroversion (range, muscle contracture or aberrant femoral torsion. The observation of aberrant femoral torsion was not anticipated before imaging studies. In addition to gluteal muscle contracture, aberrant femoral torsion can be a cause of frog-leg squatting. Level II, diagnostic study. See the guidelines for Authors for a complete description of levels of evidence.

Torsional strength of computer-aided design/computer-aided manufacturing-fabricated esthetic orthodontic brackets.

Science.gov (United States)

Alrejaye, Najla; Pober, Richard; Giordano Ii, Russell

2017-01-01

To fabricate orthodontic brackets from esthetic materials and determine their fracture resistance during archwire torsion. Computer-aided design/computer-aided manufacturing technology (Cerec inLab, Sirona) was used to mill brackets with a 0.018 × 0.025-inch slot. Materials used were Paradigm MZ100 and Lava Ultimate resin composite (3M ESPE), Mark II feldspathic porcelain (Vita Zahnfabrik), and In-Ceram YZ zirconia (Vita Zahnfabrik). Ten brackets of each material were subjected to torque by a 0.018 × 0.025-inch stainless steel archwire (G&H) using a specially designed apparatus. The average moments and degrees of torsion necessary to fracture the brackets were determined and compared with those of commercially available alumina brackets, Mystique MB (Dentsply GAC). The YZ brackets were statistically significantly stronger than any other tested material in their resistance to torsion (P brackets. Resistance of MZ100 and Lava Ultimate composite resin brackets to archwire torsion was comparable to commercially available alumina ceramic brackets.

Nonmetricity and torsion: Facts and fancies in gauge approaches to gravity

International Nuclear Information System (INIS)

Baekler, P.; Hehl, F.W.; Mielke, E.W.

1986-04-01

In general relativity, the Riemannian connection of spacetime is symmetric and metric-compatible. If we relax at first the symmetry, we arrive at a Riemann-Cartan spacetime U 4 with torsion. If we relax, additionally, the metric-compatibility, then we are led to a metric-affine spacetime (L 4 ,g) with nonmetricity and torsion. In Part 1 we turn to the (L 4 ,g) spacetime and review an appropriate framework for corresponding gravitational model theories. They can be understood as gauge approaches to the 4-dimensional affine group GL(4,R)xR 4 . They embody, in addition to the ordinary ''weak'' gravitational field, a ''strong'' piece, which is mediated by the connection and coupled to the hypermomentum current. In Part 2, by putting the nonmetricity to zero, we turn to the subcase of the Poincare gauge theory. We show in some detail, how this dynamic torsion theory can look effectively Einsteinian from a macroscopic point of view. This applies also to the Einstein-Cartan theory, which is a special case of the Poincare gauge theory for ''frozen'' torsion. In Part 3 we present new exact solutions of the Poincare gauge theory with mass, electric charge, and NUT-parameter. The properties of the new solutions are discussed. (author)

Design of a nonlinear torsional vibration absorber

Science.gov (United States)

Tahir, Ammaar Bin

Tuned mass dampers (TMD) utilizing linear spring mechanisms to mitigate destructive vibrations are commonly used in practice. A TMD is usually tuned for a specific resonant frequency or an operating frequency of a system. Recently, nonlinear vibration absorbers attracted attention of researchers due to some potential advantages they possess over the TMDs. The nonlinear vibration absorber, or the nonlinear energy sink (NES), has an advantage of being effective over a broad range of excitation frequencies, which makes it more suitable for systems with several resonant frequencies, or for a system with varying excitation frequency. Vibration dissipation mechanism in an NES is passive and ensures that there is no energy backflow to the primary system. In this study, an experimental setup of a rotational system has been designed for validation of the concept of nonlinear torsional vibration absorber with geometrically induced cubic stiffness nonlinearity. Dimensions of the primary system have been optimized so as to get the first natural frequency of the system to be fairly low. This was done in order to excite the dynamic system for torsional vibration response by the available motor. Experiments have been performed to obtain the modal parameters of the system. Based on the obtained modal parameters, the design optimization of the nonlinear torsional vibration absorber was carried out using an equivalent 2-DOF modal model. The optimality criterion was chosen to be maximization of energy dissipation in the nonlinear absorber attached to the equivalent 2-DOF system. The optimized design parameters of the nonlinear absorber were tested on the original 5-DOF system numerically. A comparison was made between the performance of linear and nonlinear absorbers using the numerical models. The comparison showed the superiority of the nonlinear absorber over its linear counterpart for the given set of primary system parameters as the vibration energy dissipation in the former is

[Theory analysis and clinical application of spirit-regulating and pain-relieving acupuncture method].

Science.gov (United States)

Chen, Liang; Tang, Lewei; Du, Huaibin; Zheng, Hui; Liang, Fanrong

2015-04-01

The theoretical foundation and scientific connotation of spirit-regulating and pain-relieving acupuncture method as well as its clinical application for pain are discussed. During spirit regulation, attention should be paid on regulating heart and brain, while acupoints should be selected mainly from the Heart Meridian, Pericardium Meridian and Governor Vessel. It has significant efficacy for refractory pain in clinical treatment. Spirit-regulating and pain-relieving acupuncture method is development of acupuncture treating spirit, and it is an important method for pain in clinic. Improvement on sensitization of pain center and brain function is considered as one of the mechanisms in spirit-regulating and pain-relieving acupuncture method.

A torsional artificial muscle from twisted nitinol microwire

Science.gov (United States)

Mirvakili, Seyed M.; Hunter, Ian W.

2017-04-01

Nitinol microwires of 25 μm in diameter can have tensile actuation of up to 4.5% in less than 100 ms. A work density of up to 480 MPa can be achieved from these microwires. In the present work, we are showing that by twisting the microwires in form of closed-loop two-ply yarn we can create a torsional actuator. We achieved a revisable torsional stroke of 46°/mm with peak rotational speed of up to 10,000 rpm. We measured a gravimetric torque of up to 28.5 N•m/kg which is higher than the 3 - 6 N•m/kg for direct-drive commercial electric motors. These remarkable performance results are comparable to those of guest-infiltrated carbon nanotube twisted yarns.

Torsionally mediated spin-rotation hyperfine splittings at moderate to high J values in methanol

Science.gov (United States)

Belov, S. P.; Golubiatnikov, G. Yu.; Lapinov, A. V.; Ilyushin, V. V.; Alekseev, E. A.; Mescheryakov, A. A.; Hougen, J. T.; Xu, Li-Hong

2016-07-01

This paper presents an explanation based on torsionally mediated proton-spin-overall-rotation interaction for the observation of doublet hyperfine splittings in some Lamb-dip sub-millimeter-wave transitions between ground-state torsion-rotation states of E symmetry in methanol. These unexpected doublet splittings, some as large as 70 kHz, were observed for rotational quantum numbers in the range of J = 13 to 34, and K = - 2 to +3. Because they increase nearly linearly with J for a given branch, we confined our search for an explanation to hyperfine operators containing one nuclear-spin angular momentum factor I and one overall-rotation angular momentum factor J (i.e., to spin-rotation operators) and ignored both spin-spin and spin-torsion operators, since they contain no rotational angular momentum operator. Furthermore, since traditional spin-rotation operators did not seem capable of explaining the observed splittings, we constructed totally symmetric "torsionally mediated spin-rotation operators" by multiplying the E-species spin-rotation operator by an E-species torsional-coordinate factor of the form e±niα. The resulting operator is capable of connecting the two components of a degenerate torsion-rotation E state. This has the effect of turning the hyperfine splitting pattern upside down for some nuclear-spin states, which leads to bottom-to-top and top-to-bottom hyperfine selection rules for some transitions, and thus to an explanation for the unexpectedly large observed hyperfine splittings. The constructed operator cannot contribute to hyperfine splittings in the A-species manifold because its matrix elements within the set of torsion-rotation A1 and A2 states are all zero. The theory developed here fits the observed large doublet splittings to a root-mean-square residual of less than 1 kHz and predicts unresolvable splittings for a number of transitions in which no doublet splitting was detected.

Determining optimal torsional ultrasound power for cataract surgery with automatic longitudinal pulses at maximum vacuum ex vivo.

Science.gov (United States)

Ronquillo, Cecinio C; Zaugg, Brian; Stagg, Brian; Kirk, Kevin R; Gupta, Isha; Barlow, William R; Pettey, Jeff H; Olson, Randall J

2014-12-01

To determine the optimal longitudinal power settings for Infiniti OZil Intelligent Phaco (IP) at varying torsional amplitude settings; and to test the hypothesis that increasing longitudinal power is more important at lower torsional amplitudes to achieve efficient phacoemulsification. Laboratory investigation. setting: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah. procedure: Individual porcine nuclei were fixed in formalin, then cut into 2.0 mm cubes. Lens cube phacoemulsification was done using OZil IP at 60%, 80%, and 100% torsional amplitude with 0%, 10%, 20%, 30%, 50%, 75%, or 100% longitudinal power. All experiments were done using a 20 gauge 0.9 mm bent reverse bevel phaco tip at constant vacuum (550 mm Hg), aspiration rate (40 mL/min), and bottle height (50 cm). main outcome measure: Complete lens particle phacoemulsification (efficiency). Linear regression analysis showed a significant increase in efficiency with increasing longitudinal power at 60% torsional amplitude (R(2) = 0.7269, P = .01) and 80% torsional amplitude (R(2) = 0.6995, P = .02) but not at 100% amplitude (R(2) = 0.3053, P = .2). Baseline comparison of 60% or 80% vs 100% torsional amplitude without longitudinal power showed increased efficiency at 100% (P = .0004). Increasing longitudinal power to 20% abolished the efficiency difference between 80% vs 100% amplitudes. In contrast, 75% longitudinal power abolished the efficiency difference between 60% vs 100% torsional amplitudes. Results suggest that longitudinal power becomes more critical at increasing phacoemulsification efficiencies at torsional amplitudes less than 100%. Increasing longitudinal power does not further increase efficiency at maximal torsional amplitudes. Copyright © 2014 Elsevier Inc. All rights reserved.

Torsional vibration signal analysis as a diagnostic tool for planetary gear fault detection

Science.gov (United States)

Xue, Song; Howard, Ian

2018-02-01

This paper aims to investigate the effectiveness of using the torsional vibration signal as a diagnostic tool for planetary gearbox faults detection. The traditional approach for condition monitoring of the planetary gear uses a stationary transducer mounted on the ring gear casing to measure all the vibration data when the planet gears pass by with the rotation of the carrier arm. However, the time variant vibration transfer paths between the stationary transducer and the rotating planet gear modulate the resultant vibration spectra and make it complex. Torsional vibration signals are theoretically free from this modulation effect and therefore, it is expected to be much easier and more effective to diagnose planetary gear faults using the fault diagnostic information extracted from the torsional vibration. In this paper, a 20 degree of freedom planetary gear lumped-parameter model was developed to obtain the gear dynamic response. In the model, the gear mesh stiffness variations are the main internal vibration generation mechanism and the finite element models were developed for calculation of the sun-planet and ring-planet gear mesh stiffnesses. Gear faults on different components were created in the finite element models to calculate the resultant gear mesh stiffnesses, which were incorporated into the planetary gear model later on to obtain the faulted vibration signal. Some advanced signal processing techniques were utilized to analyses the fault diagnostic results from the torsional vibration. It was found that the planetary gear torsional vibration not only successfully detected the gear fault, but also had the potential to indicate the location of the gear fault. As a result, the planetary gear torsional vibration can be considered an effective alternative approach for planetary gear condition monitoring.

On the energy-momentum tensor in non-linear σ-models with torsion

International Nuclear Information System (INIS)

Dorn, H.; Otto, H.J.

1987-10-01

We study the renormalization properties of the energy-momentum tensor in a σ-model with torsion. Our normal product version contains besides the classical expression and the trace anomaly an off diagonal term proportional to the squared torsion. Specialized to a group manifold this term is crucial to reproduce the correct perturbative expansion of the energy-momentum tensor in Sugawara form. (orig.)

Torsions of 3-dimensional manifolds

CERN Document Server

Wurzbacher, T

2002-01-01

From the reviews: "This is an excellent exposition about abelian Reidemeister torsions for three-manifolds." ―Zentralblatt Math "This monograph contains a wealth of information many topologists will find very handy. …Many of the new points of view pioneered by Turaev are gradually becoming mainstream and are spreading beyond the pure topology world. This monograph is a timely and very useful addition to the scientific literature." ―Mathematical Reviews

Influence of Torsion Effect on the Mechanical Characteristics of Reinforced Concrete Column

Science.gov (United States)

Wang, Debin; Fan, Guoxi

2017-11-01

The purpose of this paper is to study the effect of torsional effect and loading rate on the flexural capacity of RC members. Based on the fiber model of finite element software ABAQUS, a model has been established with the consideration of the strain rate sensitivity of steel and concrete. The model is used to reflect the influence of the rotational component of ground motion by applying the initial angular displacement. The mechanical properties of RC columns under monotonic loads are simulated. The simulation results show that there has been a decrease in the carrying capacity and initial stiffness of RC columns for high initial torsion angle. With the increase of initial torsion angle, the influence of loading rate on RC columns gradually increases.

Torsional Oscillations of the Earths's Core

Science.gov (United States)

Hide, Raymond; Boggs, Dale H.; Dickey, Jean O.

1997-01-01

Torsional oscillations of the Earth's liquid metallic outer core are investigated by diving the core into twenty imaginary e1qui-volume annuli coaxial with the axis of ratation of the Earth and determining temproal fluctuations in the axial component of angular memonetum of each annulus under the assumption of iso-rotation on cylindrical surfaces.

Torsion of cracked nanorods using a nonlocal elasticity model

International Nuclear Information System (INIS)

Loya, J A; Aranda-Ruiz, J; Fernández-Sáez, J

2014-01-01

This paper presents a nonlocal cracked-rod model from which we have analysed the torsional vibrations of a carbon nanotube with a circumferential crack. Several types of boundary conditions, including the consideration of a buckyball at the end of the nanotube, have been studied. The nonlocal Eringen elasticity theory is used to formulate the problem. The cracked rod is modelled by dividing the cracked element into two segments connected by a torsional linear spring whose stiffness is related to the crack severity. The effect of the nonlocal small-scale parameter, crack severity, cracked section position, different boundary conditions and attached mass are examined in this work. (paper)

Stress analysis and torsional buckling analysis of U-shaped bellows

International Nuclear Information System (INIS)

Watanabe, Osamu; Ohtsubo, Hideomi.

1986-01-01

This paper presents analysis of elastic stress and torsional buckling of U-shaped bellows using ring elements. The expansion joint is considered to be composed of the two toroidal sections and inner-connecting annular plates. The general thin shell theory is employed to derive strain-displacement relations of shells and plates, valid for any loadings. Numerical examples under internal pressure or axial loading are described and compared with the results of existing appropriate analysis. The fundamental aspects of torsional buckling, which have not been studied previously, will also be investigated. (author)

The Reidemeister torsion of 3-manifolds

CERN Document Server

Nicolaescu, Liviu I

2003-01-01

This is a state-of-the-art introduction to the work of Franz Reidemeister, Meng Taubes, Turaev, and the author on the concept of torsion and its generalizations. Torsion is the oldest topological (but not with respect to homotopy) invariant that in its almost eight decades of existence has been at the center of many important and surprising discoveries. During the past decade, in the work of Vladimir Turaev, new points of view have emerged, which turned out to be the "right ones" as far as gauge theory is concerned. The book features mostly the new aspects of this venerable concept. The theoretical foundations of this subject are presented in a style accessible to those, who wish to learn and understand the main ideas of the theory. Particular emphasis is upon the many and rather diverse concrete examples and techniques which capture the subleties of the theory better than any abstract general result. Many of these examples and techniques never appeared in print before, and their choice is often justified by ...

Variations of retinal nerve fiber layer thickness and ganglion cell-inner plexiform layer thickness according to the torsion direction of optic disc.

Science.gov (United States)

Lee, Kang Hoon; Kim, Chan Yun; Kim, Na Rae

2014-02-20

To examine the relationship between the optic disc torsion and peripapillary retinal nerve fiber layer (RNFL) thickness through a comparison with the macular ganglion cell inner plexiform layer complex (GCIPL) thickness measured by Cirrus optical coherence tomography (OCT). Ninety-four eyes of 94 subjects with optic disc torsion and 114 eyes of 114 subjects without optic disc torsion were enrolled prospectively. The participants underwent fundus photography and OCT imaging in peripapillary RNFL mode and macular GCIPL mode. The participants were divided into groups according to the presence or absence of optic disc torsion. The eyes with optic disc torsion were further divided into supranasal torsion and inferotemporal torsion groups according to the direction of optic disc torsion. The mean RNFL and GCIPL thicknesses for the quadrants and subsectors were compared. The superior and inferior peak locations of the RNFL were also measured according to the torsion direction. The temporal RNFL thickness was significantly thicker in inferotemporal torsion, whereas the GCIPL thickness at all segments was unaffected. The inferotemporal optic torsion had more temporally positioned superior peak locations of the RNFL than the nontorsion and supranasal-torted optic disc. Thickening of the temporal RNFL with a temporal shift in the superior peak within the eyes with inferotemporal optic disc torsion can lead to interpretation errors. The ganglion cell analysis algorithm can assist in differentiating eyes with optic disc torsion.

Conformational Effects of UV Light on DNA Origami.

Science.gov (United States)

Chen, Haorong; Li, Ruixin; Li, Shiming; Andréasson, Joakim; Choi, Jong Hyun

2017-02-01

The responses of DNA origami conformation to UV radiation of different wavelengths and doses are investigated. Short- and medium-wavelength UV light can cause photo-lesions in DNA origami. At moderate doses, the lesions do not cause any visible defects in the origami, nor do they significantly affect the hybridization capability. Instead, they help relieve the internal stress in the origami structure and restore it to the designed conformation. At high doses, staple dissociation increases which causes structural disintegration. Long-wavelength UV does not show any effect on origami conformation by itself. We show that this UV range can be used in conjunction with photoactive molecules for photo-reconfiguration, while avoiding any damage to the DNA structures.

Results from Investigations of Torsional Vibration in Turbine Set Shaft Systems

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Taradai, D. V.; Deomidova, Yu. A.; Zile, A. Z.; Tomashevskii, S. B.

2018-01-01

The article generalizes the results obtained from investigations of torsional vibration in the shaft system of the T-175/210-12.8 turbine set installed at the Omsk CHPP-5 combined heat and power plant. Three different experimental methods were used to determine the lowest natural frequencies of torsional vibration excited in the shaft system when the barring gear is switched into operation, when the generator is synchronized with the grid, and in response to unsteady disturbances caused by the grid and by the turbine control and steam admission system. It is pointed out that the experimental values of the lowest natural frequencies (to the fourth one inclusively) determined using three different methods were found to be almost completely identical with one another, even though the shaft system was stopped in the experiments carried out according to one method and the shaft system rotated at the nominal speed in those carried out according to two other methods. The need to further develop the experimental methods for determining the highest natural frequencies is substantiated. The values of decrements for the first, third, and fourth natural torsional vibration modes are obtained. A conclusion is drawn from a comparison between the calculated and experimental data on the shaft system's static twisting about the need to improve the mathematical models for calculating torsional vibration. The measurement procedure is described, and the specific features pertinent to the way in which torsional vibration manifests itself as a function of time and turbine set operating mode under the conditions of its long-term operation are considered. The fundamental measurement errors are analyzed, and their influence on the validity of measured parameters is evaluated. With an insignificant level of free and forced torsional vibrations set up under the normal conditions of turbine set and grid operation, it becomes possible to exclude this phenomenon from the list of main factors

Plant-based torsional actuator with memory

Science.gov (United States)

Nayomi Plaza; Samuel L. Zelinka; Don S. Stone; Joseph E. Jakes

2013-01-01

A bundle of a few loblolly pine (Pinus taeda) cells are moisture-activated torsional actuators that twist multiple revolutions per cm length in direct proportion to moisture content. The bundles generate 10 N m kg􀀀1 specific torque during both twisting and untwisting, which is higher than an electric motor. Additionally, the bundles exhibit a moisture-...

Harvesting electrical energy from torsional thermal actuation driven by natural convection.

Science.gov (United States)

Kim, Shi Hyeong; Sim, Hyeon Jun; Hyeon, Jae Sang; Suh, Dongseok; Spinks, Geoffrey M; Baughman, Ray H; Kim, Seon Jeong

2018-06-07

The development of practical, cost-effective systems for the conversion of low-grade waste heat to electrical energy is an important area of renewable energy research. We here demonstrate a thermal energy harvester that is driven by the small temperature fluctuations provided by natural convection. This harvester uses coiled yarn artificial muscles, comprising well-aligned shape memory polyurethane (SMPU) microfibers, to convert thermal energy to torsional mechanical energy, which is then electromagnetically converted to electrical energy. Temperature fluctuations in a yarn muscle, having a maximum hot-to-cold temperature difference of about 13 °C, were used to spin a magnetic rotor to a peak torsional rotation speed of 3,000 rpm. The electromagnetic energy generator converted the torsional energy to electrical energy, thereby producing an oscillating output voltage of up to 0.81 V and peak power of 4 W/kg, based on SMPU mass.

Measurement of torsion angles of long finger bones using computed tomography

International Nuclear Information System (INIS)

Berthold, L.D.; Ishaque, N.; Mauermann, F.; Klose, K.J.; Boehringer, G.

2001-01-01

Objective: Rotational dislocation at the fracture site is a complication of long finger bone fractures of the metacarpals and phalanges. To evaluate such deformities, we performed CT of the articular surfaces of these bones to demonstrate the torsion angles. Design: We evaluated 10 pairs of cadaver hands. These were placed flat, with the bones of interest perpendicular to the gantry to acquire axial images. The torsion of the long bone axes was defined as the angle between a tangent positioned parallel to the proximal articular surface and a tangent parallel to the distal articular surface of individual bones. Results: The maximum difference between repeated measurements was 4 . Intraobserver differences measured between right and left hands are less than 3 . Conclusion: Side differences in torsion angles exceeding 3 are strongly suspicious of a malrotation after fracture. These measurements might help to plan derotational osteotomy and assess the results of therapy. (orig.)

Torsion of a normal adnexa in a premenarcheal girl: MRI findings

International Nuclear Information System (INIS)

Bader, T.; Ranner, G.; Haberlik, A.

1996-01-01

Torsion of the adnexa can be the cause of abdominal pain. An immediate diagnosis is very important because early surgical intervention is the only way to save the ovary from necrosis. Torsion of a normal adnexa is rare, but occurs more frequently than is generally appreciated. If US findings are equivocal, MRI can provide additional information. In our case the MRI findings leading to the diagnosis of ovarian torsion were: (a) A medial ovarian mass existed with dislocation of the uterus to the affected side with hyperintense, cystic lesions on T2-weighted images at the periphery of the ovary. (b) Beaked protrusion of the mass continuing in a band-like structure connecting it with the uterus obviously represented the Fallopian tube. (c) Low and inhomogeneous signal intensity of the stroma on T1- and T2-weighted images and lack of gadolinium uptake were indicative of infarction. (orig.)

Precipitating and relieving factors of migraine versus tension type headache

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Haque Badrul

2012-08-01

Full Text Available Abstract Background To determine the differences of precipitating and relieving factors between migraine and tension type headache. Methods This is a cross sectional study. We retrospectively reviewed the records of 250 migraine patients and 250 patients diagnosed as tension type headache from the specialized headache clinic in Dept. of Neurology, Dhaka Medical College Hospital. Data were collected through a predesigned questionnaire containing information on age, sex, social status and a predetermined list of precipitating and relieving factors. Results In this study, the female patients predominated (67%. Most of the patients were within 21–30 years age group (58.6%. About 58% of them belonged to middle class families. The common precipitating factors like stress, anxiety, activity, journey, reading, cold and warm were well distributed among both the migraine and tension type headache (TTH patients. But significant difference was demonstrated for fatigue (p  Conclusion The most frequent precipitating factors for headache appear to be identical for both migraine and TTH patients. Even though some factors like fatigue, sleep deprivation, sunlight and food significantly precipitate migraine and drug, massage are effective maneuver for relieving pain among migrianeurs.

Transabdominal color doppler ultrasonography: A relevant approach for assessment of effects of uterine torsion in buffaloes

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Devender

2016-08-01

Full Text Available Aim: The present study was conducted on advanced pregnant buffaloes suffering from uterine torsion to assess the status of fetus and uterus by transabdominal ultrasonography, and the findings were compared with normal advanced pregnant buffaloes. Materials and Methods: The study was conducted on 20 clinical cases of uterine torsion and 20 normal advanced pregnant buffaloes (control group. The lower ventral area just lateral to linea alba (on both sides of the udder in standing animals was scanned transabdominally by the two-dimensional convex transducer for various ultrasonographic findings. The data collected were statistically analyzed by “one-way ANOVA” and “independent sample t-test” using computerized SPSS 16.0 software program. Results: Transabdominal ultrasonography revealed dead fetus in 95% uterine torsion cases and proved useful in imaging internal structures of fetuses while no dead fetus was reported in the control group. Size of umbilicus was found significantly decreased (p0.05 in uterine torsion group. Average thickness of the uterine wall and mean pixel values of fetal fluids (echogenicity were found significantly increased (p<0.05 in uterine torsion affected buffaloes in comparison to control group. Conclusion: Status of fetus (whether live or dead, internal status of uterus, and its contents could be determined by transabdominal ultrasonography in uterine torsion cases and thus determining the prognosis of the uterine torsion cases before going for further manipulations. This will also help in taking all the precautions to avoid death of the fetus.

Comparison of Animal Discs Used in Disc Research to Human Lumbar Disc: Torsion Mechanics and Collagen Content

Science.gov (United States)

Showalter, Brent L.; Beckstein, Jesse C.; Martin, John T.; Beattie, Elizabeth E.; Orías, Alejandro A. Espinoza; Schaer, Thomas P.; Vresilovic, Edward J.; Elliott, Dawn M.

2012-01-01

Study Design Experimental measurement and normalization of in vitro disc torsion mechanics and collagen content for several animal species used in intervertebral disc research and comparing these to the human disc. Objective To aid in the selection of appropriate animal models for disc research by measuring torsional mechanical properties and collagen content. Summary of Background Data There is lack of data and variability in testing protocols for comparing animal and human disc torsion mechanics and collagen content. Methods Intervertebral disc torsion mechanics were measured and normalized by disc height and polar moment of inertia for 11 disc types in 8 mammalian species: the calf, pig, baboon, goat, sheep, rabbit, rat, and mouse lumbar, and cow, rat, and mouse caudal. Collagen content was measured and normalized by dry weight for the same discs except the rat and mouse. Collagen fiber stretch in torsion was calculated using an analytical model. Results Measured torsion parameters varied by several orders of magnitude across the different species. After geometric normalization, only the sheep and pig discs were statistically different from human. Fiber stretch was found to be highly dependent on the assumed initial fiber angle. The collagen content of the discs was similar, especially in the outer annulus where only the calf and goat discs were statistically different from human. Disc collagen content did not correlate with torsion mechanics. Conclusion Disc torsion mechanics are comparable to human lumbar discs in 9 of 11 disc types after normalization by geometry. The normalized torsion mechanics and collagen content of the multiple animal discs presented is useful for selecting and interpreting results for animal models of the disc. Structural composition of the disc, such as initial fiber angle, may explain the differences that were noted between species after geometric normalization. PMID:22333953

[Effect of BSA on random amplified polymorphic DNA (RAPD) in plants].

Science.gov (United States)

Bian, Cai-Miao; Li, Jun-Min; Jin, Ze-Xin; Ge, Ming-Ju

2002-05-01

Using Metasequoia glyptostroboides and Heptacodium miconioides DNA as templates,the effect of bovine serum albumin (BSA) on RAPD in plants was studied. The results showed that suitable concentrations of BSA used in Metasequoia glyptostroboides and Heptacodium miconioides RAPD were different, which were 0.6 microg/microl and 1 microg/microl, respectively. The inhibition of acetylated BSA on the amplification of plant RAPD could be relieved by BSA. BSA could reduce the dosage of Taq DNA polymerase.

Moduli space of torsional manifolds

International Nuclear Information System (INIS)

Becker, Melanie; Tseng, L.-S.; Yau, S.-T.

2007-01-01

We characterize the geometric moduli of non-Kaehler manifolds with torsion. Heterotic supersymmetric flux compactifications require that the six-dimensional internal manifold be balanced, the gauge bundle be Hermitian Yang-Mills, and also the anomaly cancellation be satisfied. We perform the linearized variation of these constraints to derive the defining equations for the local moduli. We explicitly determine the metric deformations of the smooth flux solution corresponding to a torus bundle over K3

TEMPERATURE GRADIENTS IN THE SOLAR ATMOSPHERE AND THE ORIGIN OF CUTOFF FREQUENCY FOR TORSIONAL TUBE WAVES

International Nuclear Information System (INIS)

Routh, S.; Musielak, Z. E.; Hammer, R.

2010-01-01

Fundamental modes supported by a thin magnetic flux tube embedded in the solar atmosphere are typically classified as longitudinal, transverse, and torsional waves. If the tube is isothermal, then the propagation of longitudinal and transverse tube waves is restricted to frequencies that are higher than the corresponding global cutoff frequency for each wave. However, no such global cutoff frequency exists for torsional tube waves, which means that a thin and isothermal flux tube supports torsional tube waves of any frequency. In this paper, we consider a thin and non-isothermal magnetic flux tube and demonstrate that temperature gradients inside this tube are responsible for the origin of a cutoff frequency for torsional tube waves. The cutoff frequency is used to determine conditions for the wave propagation in the solar atmosphere, and the obtained results are compared to the recent observational data that support the existence of torsional tube waves in the Sun.

Torsion of normal adnexa in a 31-year-old woman: A case report and literature review

Directory of Open Access Journals (Sweden)

Nao Wakui

2018-01-01

Full Text Available It is known that a large ovarian cyst will likely cause torsion. However, normal adnexal torsion is rare and occurs in premenarchal girls in most cases. This is a case of a reproductive woman. A 31-year-old woman suffering from acute abdominal pain in the lower and right side consulted her gynecologist. The next day she had a computed tomography performed and was suspected of ovarian torsion. She did not have fever, nausea, or leukocytosis, but her abdominal pain persisted. Diagnostic laparoscopy was performed and showed torsion of the right fallopian tube, which was swollen and looked like a hydrosalpinx with a normal ovary. We did detorsion and excision of the right tube. However, pathological findings showed that the right tube was not a hydrosalpinx but was swollen due to blood stasis. We determined that this case was torsion of normal adnexa. In such cases, diagnostic laparoscopy is very effective.

Refractive variation under accommodative demand: curvital and scaled torsional variances and covariance across the meridians of the eye.

Science.gov (United States)

van Gool, R D; Harris, W F

1997-06-01

Autorefractor measurements were taken on the right eye of 10 students with an external target at vergences -1.00 and -3.00 D. The refractive errors in the form of sphere, cylinder, and axis were converted to vectors h and variance-covariance matrices calculated for different reference meridians. Scatter plots are drawn in symmetric dioptric power space. The profiles of curvital and scaled torsional variances, the scaled torsional fraction, and the scaled torsional-curvital correlation are shown using a polar representation. This form of representation provides a meridional pattern of variation under accommodative demand. The profile for scaled torsional variance is characteristically in the form of a pair of rabbit ears. At both target vergences curvital variance is larger than scaled torsional variance in all the meridians of the eye: the relative magnitudes are quantified by the scaled torsional fraction. An increase in accommodative demand generally results in an increase in variance. The rabbit ears usually become larger but less well divided. The correlation between curvital and torsional powers is usually positive in the first quadrant and negative in the second quadrant. Typical, atypical, and mean typical responses are discussed.

Comparison of torsional and microburst longitudinal phacoemulsification: a prospective, randomized, masked clinical trial.

Science.gov (United States)

Vasavada, Abhay R; Raj, Shetal M; Patel, Udayan; Vasavada, Vaishali; Vasavada, Viraj

2010-01-01

To compare intraoperative performance and postoperative outcome of three phacoemulsification technologies in patients undergoing microcoaxial phacoemulsification through 2.2-mm corneal incisions. The prospective, randomized, single-masked study included 360 eyes randomly assigned to torsional (Infiniti Vision System; Alcon Laboratories, Fort Worth, TX), microburst with longitudinal (Infiniti), or microburst with longitudinal (Legacy Everest, Alcon Laboratories) ultrasound. Assessments included surgical clock time, fluid volume, and intraoperative complications, central corneal thickness on day 1 and months 1 and 3 postoperatively, and endothelial cell density at 3 months postoperatively. Comparisons among groups were conducted. Torsional ultrasound required significantly less surgical clock time and fluid volume than the other groups. There were no intraoperative complications. Change in central corneal thickness and endothelial cell loss was significantly lower in the torsional ultrasound group at all postoperative visits (P < .001, Kruskal-Wallis test) compared to microburst longitudinal ultrasound modalities. Torsional ultrasound demonstrated quantitatively superior intraoperative performance and showed less increase in corneal thickness and less endothelial cell loss compared to microburst longitudinal ultrasound. Copyright 2010, SLACK Incorporated.

The effect of random mass, stiffness and eccentricity parameters on seismic response of torsional system

International Nuclear Information System (INIS)

Ghafory-Ashtiany, M.

2001-01-01

In this paper, the effect of random eccentricity, mass and stiffness parameter on the dynamic characteristics of structure and story shear and torsional response has been comprehensively examined. Numerical results are obtained for a five-story torsional building excited by random excitation with various damping ration and frequency parameter values using both approaches of response calculations-a more accurate complex mode and an approximate normal mode have been used. The results show that the introduction of eccentricity in a direction introduces torsional moments in the system and reduces the direct story shear. For a safe design, eccentricity should be neglected in the calculations for shear, and a value of 0.05 of radius of gyration for calculation of torsional moment should be considered, even if a structure is intended to be symmetrical

Electrically, Chemically, and Photonically Powered Torsional and Tensile Actuation of Hybrid Carbon Nanotube Yarn Muscles

Science.gov (United States)

Lima, Márcio D.; Li, Na; Jung de Andrade, Mônica; Fang, Shaoli; Oh, Jiyoung; Spinks, Geoffrey M.; Kozlov, Mikhail E.; Haines, Carter S.; Suh, Dongseok; Foroughi, Javad; Kim, Seon Jeong; Chen, Yongsheng; Ware, Taylor; Shin, Min Kyoon; Machado, Leonardo D.; Fonseca, Alexandre F.; Madden, John D. W.; Voit, Walter E.; Galvão, Douglas S.; Baughman, Ray H.

2012-11-01

Artificial muscles are of practical interest, but few types have been commercially exploited. Typical problems include slow response, low strain and force generation, short cycle life, use of electrolytes, and low energy efficiency. We have designed guest-filled, twist-spun carbon nanotube yarns as electrolyte-free muscles that provide fast, high-force, large-stroke torsional and tensile actuation. More than a million torsional and tensile actuation cycles are demonstrated, wherein a muscle spins a rotor at an average 11,500 revolutions/minute or delivers 3% tensile contraction at 1200 cycles/minute. Electrical, chemical, or photonic excitation of hybrid yarns changes guest dimensions and generates torsional rotation and contraction of the yarn host. Demonstrations include torsional motors, contractile muscles, and sensors that capture the energy of the sensing process to mechanically actuate.

Resistance of i-beams in warping torsion with account for the development of plasticdeformations

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Tusnin Aleksandr Romanovich

2014-01-01

Full Text Available Torsion of thin-walled open-section beams due to restrained warping displacements of cross-section is causing additional stresses, which make a significant contribution to the total stress. Due to plastic deformation there are certain reserves of bearing capacity, identification of which is of significant practical interest. The existing normative documents for the design of steel structures in Russia do not include design factor taking into account the development of plastic deformation during warping torsion. The analysis of thin-walled open-section members with plastic deformation will more accurately determine their load-bearing capacity and requires further research. Reserves of the beams bearing capacity due to the development of plastic deformations are revealed when beams are influenced by bending, as well as tension and compression. The existing methodology of determining these reserves and the plastic shape factor in bending was reviewed. This has allowed understanding how it was possible to solve this problem for warping torsion members and outline possible ways of theoretical studies of the bearing capacity in warping torsion. The authors used theoretical approach in determining this factor for the symmetric I-section beam under the action of bimoment and gave recommendations for the design of torsion members including improved value of plastic shape factor.

Intravaginal testicular torsion in newborns. To fix or not to fix the contralateral testis?

Directory of Open Access Journals (Sweden)

G. Bordin

2013-10-01

Full Text Available Scrotal swelling suggesting testicular torsion is a rare urological emergency which requires a clinical urgent evaluation and most of the times must be managed surgically. In newborns it can occur in the postnatal period, usually within the twenty-eighth day of life, or more frequently in utero, during the descent of the testis into the scrotum. Usually its poor fixedness allows the testis an abnormal mobility inside the scrotum, configuring the framework of extravaginal torsion. On the contrary during the perinatal period a twist that takes place inside the tunica vaginalis, known as intravaginal torsion, is extremely uncommon and only few cases are well documented in the literature. Authors present a rare case of intravaginal testicular torsion occurred in perinatal period. In this situation only the early surgical exploration of the scrotum may allow the rescue of the gonad, although in rare cases. Timing of surgical treatment and need for contralateral testicular fixation remain controversial. However since the anatomical defect of the tunica vaginalis can be bilateral the surgical fixation even of the contralateral testis is important, now or later, in order to prevent any future torsion of this gonad. The authors also present a brief review of recent literature on the subject.

Biothermal sensing of a torsional artificial muscle.

Science.gov (United States)

Lee, Sung-Ho; Kim, Tae Hyeob; Lima, Márcio D; Baughman, Ray H; Kim, Seon Jeong

2016-02-14

Biomolecule responsive materials have been studied intensively for use in biomedical applications as smart systems because of their unique property of responding to specific biomolecules under mild conditions. However, these materials have some challenging drawbacks that limit further practical application, including their speed of response and mechanical properties, because most are based on hydrogels. Here, we present a fast, mechanically robust biscrolled twist-spun carbon nanotube yarn as a torsional artificial muscle through entrapping an enzyme linked to a thermally sensitive hydrogel, poly(N-isopropylacrylamide), utilizing the exothermic catalytic reaction of the enzyme. The induced rotation reached an equilibrated angle in less than 2 min under mild temperature conditions (25-37 °C) while maintaining the mechanical properties originating from the carbon nanotubes. This biothermal sensing of a torsional artificial muscle offers a versatile platform for the recognition of various types of biomolecules by replacing the enzyme, because an exothermic reaction is a general property accompanying a biochemical transformation.

Nonlinear modulation of torsional waves in elastic rod. [Instability

Energy Technology Data Exchange (ETDEWEB)

Hirao, M; Sugimoto, N [Osaka Univ., Toyonaka (Japan). Faculty of Engineering Science

1977-06-01

Nonlinear Schroedinger equation, which describes the nonlinear modulation of dispersive torsional waves in an elastic rod of circular cross-section, is derived by the derivative expansion method. It is found, for the lowest dispersive mode, that the modulational instability occurs except in the range of the carrier wavenumber, 2.799torsional and its second-harmonic longitudinal modes.

Influence of torsion and tensile stress on magnetoimpedance effect in Fe-rich amorphous microwires at high frequencies

Energy Technology Data Exchange (ETDEWEB)

Garcia, C. [Dpto. Fisica de Materiales, Fac. Quimicas, UPV/EHU, 20018 San Sebastian (Spain)]. E-mail: wubgagac@sc.ehu.es; Chizhik, A. [Dpto. Fisica de Materiales, Fac. Quimicas, UPV/EHU, 20018 San Sebastian (Spain); Zhukov, A. [Dpto. Fisica de Materiales, Fac. Quimicas, UPV/EHU, 20018 San Sebastian (Spain); Zhukova, V. [TAMAG Iberica S. L. Parque Tecnologico de Miramon, Paseo Mikeletegi 56, 1a Planta, 20009 San Sebastian (Spain); Gonzalez, J. [Dpto. Fisica de Materiales, Fac. Quimicas, UPV/EHU, 20018 San Sebastian (Spain); Blanco, J.M. [Dpto. Fisica Aplicada I. EUPDS, UPV/EHU, Plaza Europa 1, 20018 San Sebastian (Spain); Panina, L.V. [University of Plymouth, Drakes Circus, Plymouth (United Kingdom)

2007-09-15

In this work, we study the magnetoimpedance response under tensile and torsional stress of Fe{sub 76}B{sub 13}Si{sub 11} glass-coated amorphous microwires (with the metallic nucleus diameter of 17 {mu}m) prepared by Taylor-Ulitovski method. The impedance was evaluated using a Network Analyser in the frequency range of 10-500 MHz. In order to induce a helical magnetic anisotropy that modifies the magnetic domain structure and the magnetic response of the sample, the torsion stresses have been applied. The effect of such torsion on giant magnetoimpedance (GMI) has been studied in a Fe-rich amorphous microwire as a function of the driving current frequency. Unusual behaviour of the GMI with torsion has been observed up to 500 MHz: at this frequency, the change from double-peak to single-peak behaviour has been observed. It could be ascribed to changes on domain structures and surface anisotropy induced by applied torsion. For this frequency range, an abrupt decrease of the impedance with torsion has been observed. We have also studied the tensile-induced changes of GMI effect in a Fe-rich amorphous microwire. The GMI effect increases with applied tensile stress and with the frequency of AC current. Observed dependences could be attributed to the change of the overall magnetic anisotropy under applied torsion.

New torsion black hole solutions in Poincaré gauge theory

Energy Technology Data Exchange (ETDEWEB)

Cembranos, Jose A.R.; Valcarcel, Jorge Gigante, E-mail: cembra@fis.ucm.es, E-mail: jorgegigante@ucm.es [Departamento de Física Teórica I, Universidad Complutense de Madrid, Av. Complutense s/n, E-28040 Madrid (Spain)

2017-01-01

We derive a new exact static and spherically symmetric vacuum solution in the framework of the Poincaré gauge field theory with dynamical massless torsion. This theory is built in such a form that allows to recover General Relativity when the first Bianchi identity of the model is fulfilled by the total curvature. The solution shows a Reissner-Nordström type geometry with a Coulomb-like curvature provided by the torsion field. It is also shown the existence of a generalized Reissner-Nordström-de Sitter solution when additional electromagnetic fields and/or a cosmological constant are coupled to gravity.

A black hole with torsion in 5D Lovelock gravity

Science.gov (United States)

Cvetković, B.; Simić, D.

2018-03-01

We analyze static spherically symmetric solutions of five dimensional (5D) Lovelock gravity in the first order formulation. In the Riemannian sector, when torsion vanishes, the Boulware–Deser black hole represents a unique static spherically symmetric black hole solution for the generic choice of the Lagrangian parameters. We show that a special choice of the Lagrangian parameters, different from the Lovelock Chern–Simons gravity, leads to the existence of a static black hole solution with torsion, the metric of which is asymptotically anti-de Sitter (AdS). We calculate the conserved charges and thermodynamical quantities of this black hole solution.

The Design and Performance Evaluation of Hydroformed Tubular Torsion Beam Axle

Science.gov (United States)

Kim, Jaehyun; Oh, Jinho; Choi, Hanho

2010-06-01

Suspensions for vehicles are structural devices used for suspending a vehicle body and absorbing shocks from the road. Thus, the suspensions must be designed such that they can attenuate shocks from a road and make passengers feel comfortable despite the shocks, and improve steering stability, determined by the ground contact force of tires during running of vehicles. Another important factor to be considered while designing suspensions is that the suspensions must maintain desired stiffness and desired durability despite the repeated application of shocks from roads thereto. The present relates, in general, to a tubular torsion beam for rear suspensions of vehicles and a manufacturing method thereof and, more particularly, to the provision of tubular torsion beams having excellent roll stiffness and excellent roll strength, produced through hydroforming. The hydroforming technology has a lot of benefit which is shape accuracy, good durability caused by compressive pressure, and good forming quality. In this study, the performance evaluation of the hydroformed tubular torsion beam axle is evaluated.

Force-dependent melting of supercoiled DNA at thermophilic temperatures.

Science.gov (United States)

Galburt, E A; Tomko, E J; Stump, W T; Ruiz Manzano, A

2014-01-01

Local DNA opening plays an important role in DNA metabolism as the double-helix must be melted before the information contained within may be accessed. Cells finely tune the torsional state of their genomes to strike a balance between stability and accessibility. For example, while mesophilic life forms maintain negatively superhelical genomes, thermophilic life forms use unique mechanisms to maintain relaxed or even positively supercoiled genomes. Here, we use a single-molecule magnetic tweezers approach to quantify the force-dependent equilibrium between DNA melting and supercoiling at high temperatures populated by Thermophiles. We show that negatively supercoiled DNA denatures at 0.5 pN lower tension at thermophilic vs. mesophilic temperatures. This work demonstrates the ability to monitor DNA supercoiling at high temperature and opens the possibility to perform magnetic tweezers assays on thermophilic systems. The data allow for an estimation of the relative energies of base-pairing and DNA bending as a function of temperature and support speculation as to different general mechanisms of DNA opening in different environments. Lastly, our results imply that average in vivo DNA tensions range between 0.3 and 1.1 pN. Copyright © 2014 Elsevier B.V. All rights reserved.

Torsional asymmetry in suspension bridge systems

Czech Academy of Sciences Publication Activity Database

Malík, Josef

2015-01-01

Roč. 60, č. 6 (2015), s. 677-701 ISSN 0862-7940 R&D Projects: GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : suspension bridge * Hamilton principle * vertical and torsional oscillation * uniqueness * existence Subject RIV: BA - General Mathematics Impact factor: 0.507, year: 2015 http://link.springer.com/article/10.1007%2Fs10492-015-0117-3

Mordell-Weil torsion in the mirror of multi-sections

Energy Technology Data Exchange (ETDEWEB)

Oehlmann, Paul-Konstantin [Physics Department, Virginia Tech, Robeson Hall 0435, 850 West Campus Drive, Blacksburg, VA, 24061 (United States); Bethe Center for Theoretical Physics, Physikalisches Institut der Universität Bonn,Nussallee 12, Bonn, 53115 (Germany); Reuter, Jonas; Schimannek, Thorsten [Bethe Center for Theoretical Physics, Physikalisches Institut der Universität Bonn,Nussallee 12, Bonn, 53115 (Germany)

2016-12-12

We give further evidence that genus-one fibers with multi-sections are mirror dual to fibers with Mordell-Weil torsion. In the physics of F-theory compactifications this implies a relation between models with a non-simply connected gauge group and those with discrete symmetries. We provide a combinatorial explanation of this phenomenon for toric hypersurfaces. In particular this leads to a criterion to deduce Mordell-Weil torsion directly from the polytope. For all 3134 complete intersection genus-one curves in three-dimensional toric ambient spaces we confirm the conjecture by explicit calculation. We comment on several new features of these models: the Weierstrass forms of many models can be identified by relabeling the coefficient sections. This reduces the number of models to 1024 inequivalent ones. We give an example of a fiber which contains only non-toric sections one of which becomes toric when the fiber is realized in a different ambient space. Similarly a singularity in codimension one can have a toric resolution in one representation while it is non-toric in another. Finally we give a list of 24 inequivalent genus-one fibers that simultaneously exhibit multi-sections and Mordell-Weil torsion in the Jacobian. We discuss a self-mirror example from this list in detail.

Torsionally mediated spin-rotation hyperfine splittings at moderate to high J values in methanol

Energy Technology Data Exchange (ETDEWEB)

Belov, S. P.; Golubiatnikov, G. Yu.; Lapinov, A. V. [Institute of Applied Physics of the Russian Academy of Sciences, 46 Ulyanov Street, 603950 Nizhny Novgorod (Russian Federation); Ilyushin, V. V.; Mescheryakov, A. A. [Institute of Radio Astronomy of National Academy of Sciences of Ukraine, Chervonopraporna 4, 61002 Kharkov (Ukraine); Alekseev, E. A. [Institute of Radio Astronomy of National Academy of Sciences of Ukraine, Chervonopraporna 4, 61002 Kharkov (Ukraine); Quantum Radiophysics Department of V. N. Karazin Kharkiv National University, Svobody Square 4, 61022 Kharkov (Ukraine); Hougen, J. T., E-mail: jon.hougen@nist.gov [Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8441 (United States); Xu, Li-Hong [Department of Physics and Centre for Laser, Atomic, and Molecular Sciences, University of New Brunswick, Saint John, New Brunswick E2L 4L5 (Canada)

2016-07-14

This paper presents an explanation based on torsionally mediated proton-spin–overall-rotation interaction for the observation of doublet hyperfine splittings in some Lamb-dip sub-millimeter-wave transitions between ground-state torsion-rotation states of E symmetry in methanol. These unexpected doublet splittings, some as large as 70 kHz, were observed for rotational quantum numbers in the range of J = 13 to 34, and K = − 2 to +3. Because they increase nearly linearly with J for a given branch, we confined our search for an explanation to hyperfine operators containing one nuclear-spin angular momentum factor I and one overall-rotation angular momentum factor J (i.e., to spin-rotation operators) and ignored both spin-spin and spin-torsion operators, since they contain no rotational angular momentum operator. Furthermore, since traditional spin-rotation operators did not seem capable of explaining the observed splittings, we constructed totally symmetric “torsionally mediated spin-rotation operators” by multiplying the E-species spin-rotation operator by an E-species torsional-coordinate factor of the form e{sup ±niα}. The resulting operator is capable of connecting the two components of a degenerate torsion-rotation E state. This has the effect of turning the hyperfine splitting pattern upside down for some nuclear-spin states, which leads to bottom-to-top and top-to-bottom hyperfine selection rules for some transitions, and thus to an explanation for the unexpectedly large observed hyperfine splittings. The constructed operator cannot contribute to hyperfine splittings in the A-species manifold because its matrix elements within the set of torsion-rotation A{sub 1} and A{sub 2} states are all zero. The theory developed here fits the observed large doublet splittings to a root-mean-square residual of less than 1 kHz and predicts unresolvable splittings for a number of transitions in which no doublet splitting was detected.

The efficacy of rotational control designs in promoting torsional stability of hip fracture fixation.

Science.gov (United States)

Gosiewski, J D; Holsgrove, T P; Gill, H S

2017-05-01

Fractures of the proximal femur are a common clinical problem, and a number of orthopaedic devices are available for the treatment of such fractures. The objective of this study was to assess the rotational stability, a common failure predictor, of three different rotational control design philosophies: a screw, a helical blade and a deployable crucifix. Devices were compared in terms of the mechanical work (W) required to rotate the implant by 6° in a bone substitute material. The substitute material used was Sawbones polyurethane foam of three different densities (0.08 g/cm 3 , 0.16 g/cm 3 and 0.24 g/cm 3 ). Each torsion test comprised a steady ramp of 1°/minute up to an angular displacement of 10°. The deployable crucifix design (X-Bolt), was more torsionally stable, compared to both the dynamic hip screw (DHS, p = 0.008) and helical blade (DHS Blade, p= 0.008) designs in bone substitute material representative of osteoporotic bone (0.16 g/cm 3 polyurethane foam). In 0.08 g/cm 3 density substrate, the crucifix design (X-Bolt) had a higher resistance to torsion than the screw (DHS, p = 0.008). There were no significant differences (p = 0.101) between the implants in 0.24 g/cm 3 density bone substitute. Our findings indicate that the clinical standard proximal fracture fixator design, the screw (DHS), was the least effective at resisting torsional load, and a novel crucifix design (X-Bolt), was the most effective design in resisting torsional load in bone substitute material with density representative of osteoporotic bone. At other densities the torsional stability was also higher for the X-Bolt, although not consistently significant by statistical analysis. Cite this article : J. D. Gosiewski, T. P. Holsgrove, H. S. Gill. The efficacy of rotational control designs in promoting torsional stability of hip fracture fixation. Bone Joint Res 2017;6:270-276. DOI: 10.1302/2046-3758.65.BJR-2017-0287.R1. © 2017 Gosiewski et al.

Lateral-torsional buckling resistance of cellular beams

NARCIS (Netherlands)

Sonck, Delphine; Belis, Jan

The evenly spaced circular web openings in I-section cellular beams have an advantageous effect on the material use if these beams are loaded in strong-axis bending. However, not all aspects of the behaviour of such beams have been studied adequately, such as the lateral–torsional buckling failure.

Modeling Friction Performance of Drill String Torsional Oscillation Using Dynamic Friction Model

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Xingming Wang

2017-01-01

Full Text Available Drill string torsional and longitudinal oscillation can significantly reduce axial drag in horizontal drilling. An improved theoretical model for the analysis of the frictional force was proposed based on microscopic contact deformation theory and a bristle model. The established model, an improved dynamic friction model established for drill strings in a wellbore, was used to determine the relationship of friction force changes and the drill string torsional vibration. The model results were in good agreement with the experimental data, verifying the accuracy of the established model. The analysis of the influence of drilling mud properties indicated that there is an approximately linear relationship between the axial friction force and dynamic shear and viscosity. The influence of drill string torsional oscillation on the axial friction force is discussed. The results indicated that the drill string transverse velocity is a prerequisite for reducing axial friction. In addition, low amplitude of torsional vibration speed can significantly reduce axial friction. Then, increasing the amplitude of transverse vibration speed, the effect of axial reduction is not significant. In addition, by involving general field drilling parameters, this model can accurately describe the friction behavior and quantitatively predict the frictional resistance in horizontal drilling.

On the relationship between tibia torsional deformation and regional muscle contractions in habitual human exercises in vivo.

Science.gov (United States)

Yang, Peng-Fei; Kriechbaumer, Andreas; Albracht, Kirsten; Sanno, Maximilian; Ganse, Bergita; Koy, Timmo; Shang, Peng; Brüggemann, Gert-Peter; Müller, Lars Peter; Rittweger, Jörn

2015-02-05

The mechanical relationship between bone and muscle has been long recognized. However, it still remains unclear how muscles exactly load on bone. In this study, utilizing an optical segment tracking technique, the in vivo tibia loading regimes in terms of tibia segment deformation in humans were investigated during walking, forefoot and rear foot stair ascent and running and isometric plantar flexion. Results suggested that the proximal tibia primarily bends to the posterior aspect and twists to the external aspect with respect to the distal tibia. During walking, peak posterior bending and peak torsion occurred in the first half (22%) and second half (76%) of the stance phase, respectively. During stair ascent, two noticeable peaks of torsion were found with forefoot strike (38% and 82% of stance phase), but only one peak of torsion was found with rear foot strike (78% of stance phase). The torsional deformation angle during both stair ascent and running was larger with forefoot strike than rear foot strike. During isometric plantar flexion, the tibia deformation regimes were characterized more by torsion (maximum 1.35°) than bending (maximum 0.52°). To conclude, bending and torsion predominated the tibia loading regimes during the investigated activities. Tibia torsional deformation is closely related to calf muscle contractions, which further confirm the notion of the muscle-bone mechanical link and shift the focus from loading magnitude to loading regimes in bone mechanobiology. It thus is speculated that torsion is another, yet under-rated factor, besides the compression and tension, to drive long bone mechano-adaptation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ghrelin and NUCB2/Nesfatin-1 expression in unilateral testicular torsion-induced rats with and without N-acetylcysteine.

Science.gov (United States)

Sarac, M; Bakal, U; Tartar, T; Kuloglu, T; Yardim, M; Artas, G; Aydin, S; Kazez, A

2017-08-15

Testicular torsion (TT) is a common urological problem in the field of pediatric surgery. The degree and duration of torsion determines the degree of testicular damage; however, its effects on the expression of octanoylated ghrelin and nucleobindin 2 (NUCB2) /nesfatin-1 synthetized from testicular tissue remain unclear. We explored the effects of experimentally induced unilateral TT on serum and contralateral testicular tissue ghrelin and NUCB2/nesfatin-1 levels, and determined whether N-acetyl cysteine (NAS) treatment had any effects on their expression. A total of 42 Wistar Albino strain rats were divided into 7 groups: Group (G) I control, GII sham, GIII 12-hour torsion, GIV 12-hour torsion + detorsion + 100 mg/kg NAS, GV 24-hour torsion, GVI 24-hour torsion + detorsion + 100 mg/kg NAS, and GVII 100 mg/kg NAS. Octanoylated ghrelin and NUCB2/nesfatin-1 concentrations were evaluated in serum using the ELISA method and in testicular tissue with immunohistochemical methods. Immunoreactivity of octanoylated ghrelin significantly increased in GI compared to GIII, GV, and GVI (p<0.05). NUCB2/nesfatin-1 immunoreactivity increased in GV and GVIII relative to GI (p<0.05). In the 12-hour torsion group, a significant decrease in octanoylated ghrelin levels with NAS treatment was observed; however, in the 24-hour torsion group, a significant decrease was not observed. In the 12-hour torsion + NAS treatment group, a significant change was not observed in NUCB2/nesfatin-1 expression. Following 24-hour torsion, an increase in NUCB2/nesfatin-1 levels was observed, and NAS treatment did not reverse this increase. It was determined that increases in the expression of octanoylated ghrelin and NUCB2/nesfatin-1, the latter of which was a result of TT, reflect damage in this tissue. Importantly, NAS treatment could prevent this damage. Thus, there may be a clinical application for the combined use of NAS and octanoylated ghrelin in preventing TT-related infertility.

Room temperature fatigue behaviour of a normalized steel SAE 4140 in torsion

International Nuclear Information System (INIS)

Klumpp, S.; Eifler, D.; Macherauch, E.

1990-01-01

Cyclic deformation behaviour of a normalized steel SAE 4140 in shear strain-controlled torsion is characterized by cyclic softening and cyclic hardening. If mean shear stresses are superimposed to an alternating shear stress, cycle-dependent creep occurs, and the number of cycles to failure decreases. In shear strain-controlled torsional loading, mean stresses are observed to relax nearly to zero within a few cycles. Fatigue life is not influenced by mean shear strains. (orig.) [de

Wing Torsional Stiffness Tests of the Active Aeroelastic Wing F/A-18 Airplane

Science.gov (United States)

Lokos, William A.; Olney, Candida D.; Crawford, Natalie D.; Stauf, Rick; Reichenbach, Eric Y.

2002-01-01

The left wing of the Active Aeroelastic Wing (AAW) F/A-18 airplane has been ground-load-tested to quantify its torsional stiffness. The test has been performed at the NASA Dryden Flight Research Center in November 1996, and again in April 2001 after a wing skin modification was performed. The primary objectives of these tests were to characterize the wing behavior before the first flight, and provide a before-and-after measurement of the torsional stiffness. Two streamwise load couples have been applied. The wing skin modification is shown to have more torsional flexibility than the original configuration has. Additionally, structural hysteresis is shown to be reduced by the skin modification. Data comparisons show good repeatability between the tests.

Adnexal Torsion during Pregnancy after Oocyte In Vitro Maturation and Intracytoplasmic Sperm Injection Cycle

Directory of Open Access Journals (Sweden)

Simone Giulini

2010-01-01

Full Text Available We report a case of right adnexal torsion during pregnancy after an oocyte in vitro maturation and intracitoplasmic sperm injection cycle in patient with polycystic ovary syndrome. A 31-year-old woman with a typical clinical disorder of polycystic ovarian syndrome was included in an oocyte in vitro maturation program. Right adnexal torsion occurred two days after embryo transfer, and laparoscopy detorsion was successfully performed with preservation of adnexa. The patient had a full-term pregnancy and delivered a healthy infant at 40 weeks of gestation. To our knowledge this is the first report of adnexal torsion after an oocyte in vitro maturation and intracitoplasmic sperm injection program.

Effect of torsion angle on electronic transport through different anchoring groups in molecular junction

International Nuclear Information System (INIS)

Xia Caijuan; Fang Changfeng; Zhao Peng; Xie Shijie; Liu Desheng

2009-01-01

By applying nonequilibrium Green's function formalism combined with first-principles density functional theory, we investigate effect of torsion angle on electronic transport properties of 4,4 ' -biphenyl molecule connected with different anchoring groups (dithiocarboxylate and thiol group) to Au(111) electrodes. The influence of the HOMO-LUMO gaps and the spatial distributions of molecular orbitals on the quantum transport through the molecular device are discussed. Theoretical results show that the torsion angle plays important role in conducting behavior of molecular devices. By changing the torsion angle between two phenyl rings, namely changing the magnitude of the intermolecular coupling effect, a different transport behavior can be observed in these two systems.

Premotor neurons encode torsional eye velocity during smooth-pursuit eye movements

Science.gov (United States)

Angelaki, Dora E.; Dickman, J. David

2003-01-01

Responses to horizontal and vertical ocular pursuit and head and body rotation in multiple planes were recorded in eye movement-sensitive neurons in the rostral vestibular nuclei (VN) of two rhesus monkeys. When tested during pursuit through primary eye position, the majority of the cells preferred either horizontal or vertical target motion. During pursuit of targets that moved horizontally at different vertical eccentricities or vertically at different horizontal eccentricities, eye angular velocity has been shown to include a torsional component the amplitude of which is proportional to half the gaze angle ("half-angle rule" of Listing's law). Approximately half of the neurons, the majority of which were characterized as "vertical" during pursuit through primary position, exhibited significant changes in their response gain and/or phase as a function of gaze eccentricity during pursuit, as if they were also sensitive to torsional eye velocity. Multiple linear regression analysis revealed a significant contribution of torsional eye movement sensitivity to the responsiveness of the cells. These findings suggest that many VN neurons encode three-dimensional angular velocity, rather than the two-dimensional derivative of eye position, during smooth-pursuit eye movements. Although no clear clustering of pursuit preferred-direction vectors along the semicircular canal axes was observed, the sensitivity of VN neurons to torsional eye movements might reflect a preservation of similar premotor coding of visual and vestibular-driven slow eye movements for both lateral-eyed and foveate species.

Congenital or torsion-induced absence of Fallopian tubes. Two case reports.

Science.gov (United States)

Paternoster, D M; Costantini, W; Uglietti, A; Vasile, C; Bocconi, L

1998-05-01

Unilateral absence of a uterine tube is an extremely rare finding, for which there are two possible etiopathogenic causes: in some cases it is due to haemorrhage filling of the cavity and its reabsorption as a result of asymptomatic torsion of the uterine tube during adult life, in pediatric age or even during intrauterine life; alternatively, the absence may be congenital, associated with developmental alterations of the mesonephric and paramesonephric ducts. The article presents two cases of fallopian tube absence: a congenital monolateral absence and a tubal torsion during pregnancy. The symptomatology of the torsion of the fallopian tube in pregnancy can be milder than in the classic description with peritoneal reaction and severe clinical alteration. The main risk factors for tubal torsion are: adhesions and inflammatory processes, ovarian cysts, usually of dermoid type, menstrual period, pregnancy, abnormal long mesosalpinx and/or mesovarium, pelvic congestion induced by constipation and disturbed venous blood flow from the adnexa. A congenital defect of the mesonephric duct is followed by a homolateral defect of the paramesonephric duct. The resulting anomaly is characterized by the absence of the uterine tube, uterus-tube angle, kidney and ureter. Partial or total unilateral defects of a paramesonephric duct are more common than aplasia of both ducts. Some authors have suggested that an inadequate blood supply during the descent into the pelvis of the caudal part of the paramesonephric duct might feasibly lead to incomplete tube development.

Tensile and Torsional Structural Properties of the Native Scapholunate Ligament.

Science.gov (United States)

Pang, Eric Quan; Douglass, Nathan; Behn, Anthony; Winterton, Matthew; Rainbow, Michael J; Kamal, Robin N

2018-02-17

The ideal material for reconstruction of the scapholunate interosseous ligament (SLIL) should replicate the mechanical properties of the native SLIL to recreate normal kinematics and prevent posttraumatic arthritis. The purpose of our study was to evaluate the cyclic torsional and tensile properties of the native SLIL and load to failure tensile properties of the dorsal SLIL. The SLIL bone complex was resected from 10 fresh-frozen cadavers. The scaphoid and lunate were secured in polymethylmethacrylate and mounted on a test machine that incorporated an x-y stage and universal joint, which permitted translations perpendicular to the rotation/pull axis as well as nonaxial angulations. After a 1 N preload, specimens underwent cyclic torsional testing (±0.45 N m flexion/extension at 0.5 Hz) and tensile testing (1-50 N at 1 Hz) for 500 cycles. Lastly, the dorsal 10 mm of the SLIL was isolated and displaced at 10 mm/min until failure. During intact SLIL cyclic torsional testing, the neutral zone was 29.7° ± 6.6° and the range of rotation 46.6° ± 7.1°. Stiffness in flexion and extension were 0.11 ± 0.02 and 0.12 ± 0.02 N m/deg, respectively. During cyclic tensile testing, the engagement length was 0.2 ± 0.1 mm, the mean stiffness was 276 ± 67 N/mm, and the range of displacement was 0.4 ± 0.1 mm. The dorsal SLIL displayed a 0.3 ± 0.2 mm engagement length, 240 ± 65 N/mm stiffness, peak load of 270 ± 91 N, and displacement at peak load of 1.8 ± 0.3 mm. We report the torsional properties of the SLIL. Our novel test setup allows for free rotation and translation, which reduces out-of-plane force application. This may explain our observation of greater dorsal SLIL load to failure than previous reports. By matching the natural ligament with respect to its tensile and torsional properties, we believe that reconstructions will better restore the natural kinematics of the wrist and lead to improved outcomes. Future clinical studies should aim to investigate this

Torsion method for measuring piezooptic coefficients

Energy Technology Data Exchange (ETDEWEB)

Skab, I.; Smaga, I.; Savaryn, V.; Vasylkiv, Yu.; Vlokh, R. [Institute of Physical Optics, Lviv (Ukraine)

2011-01-15

We develop and describe analytically a torsion method for measuring piezooptic coefficients associated with shear stresses. It is shown that the method enables to increase significantly the accuracy of determination of piezooptic coefficients. The method and the appropriate apparatus are verified experimentally on the example of LiNbO{sub 3} crystals. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Timoshenko-Wagner-Kappus Torsion Bending Theory and Wind ...

Indian Academy of Sciences (India)

Theory and Wind Tunnel Balance Design. S P Govinda ... The study of torsion and bending has always been a favourite ... Since it was difficult to work quietlyin Petersburg, .... should be stiff and strong to endure shocks and ensure long life.

Torsional Vibrations of a Conic Shaft with Opposite Tapers Carrying Arbitrary Concentrated Elements

Directory of Open Access Journals (Sweden)

Jia-Jang Wu

2013-01-01

Full Text Available The purpose of this paper is to present the exact solution for free torsional vibrations of a linearly tapered circular shaft carrying a number of concentrated elements. First of all, the equation of motion for free torsional vibration of a conic shaft is transformed into a Bessel equation, and, based on which, the exact displacement function in terms of Bessel functions is obtained. Next, the equations for compatibility of deformations and equilibrium of torsional moments at each attaching point (including the shaft ends between the concentrated elements and the conic shaft with positive and negative tapers are derived. From the last equations, a characteristic equation of the form is obtained. Then, the natural frequencies of the torsional shaft are determined from the determinant equation , and, corresponding to each natural frequency, the column vector for the integration constants, , is obtained from the equation . Substitution of the last integration constants into the associated displacement functions gives the corresponding mode shape of the entire conic shaft. To confirm the reliability of the presented theory, all numerical results obtained from the exact method are compared with those obtained from the conventional finite element method (FEM and good agreement is achieved.

Natural Frequncies of Coupled Blade-Bending and Shaft-Torsional Vibrations

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B.O. Al-Bedoor

2007-01-01

Full Text Available In this study, the coupled shaft-torsional and blade-bending natural frequencies are investigated using a reduced order mathematical model. The system-coupled model is developed using the Lagrangian approach in conjunction with the assumed modes method to discretize the blade bending deflection. The model accounts for the blade stagger (setting angle, the system rotating speed and its induced stiffening effect. The coupled equations of motion are linearized based on the small deformation theory for the blade bending and shaft torsional deformation to enable calculation of the system natural frequencies for various combinations of system parameters. The obtained coupled eignvalue system is ready for use as a reference for comparison for larger size finite element simulations and for the use as a fast check on natural frequencies for the coupled blade bending and shaft torsional vibrations in the design and diagnostics processes. Some results on the predicted natural frequencies are graphically presented and discussed pertinent to the coupling controlling factors and their effects. In addition, the predicted coupled natural frequencies are validated using the Finite Element Commercial Package (Pro-Mechanica where good agreements are found.

Torsion of a Wandering Spleen Presenting as Acute Abdomen

International Nuclear Information System (INIS)

Chauhan, Narvir Singh; Kumar, Satish

2016-01-01

Wandering spleen is a rare condition which if uncorrected, can result in torsion and infarction. Clinical presentation of a wandering spleen can vary from asymptomatic abdominal mass to acute abdominal pain. Radiological investigations play a pivotal role in diagnosis as the clinical diagnosis is usually impossible. We present a case of wandering spleen with torsion and complete infarction that occurred in a 32-year-old multiparous female. The diagnosis was established preoperatively on colour Doppler and CT of the abdomen with subsequent confirmation on surgery. Wandering spleen is a rare clinical condition which can present as acute abdomen. An increased awareness of this entity together with the timely use of ultrasound and CT of the abdomen can play an important role in preoperative diagnosis and surgical management

Electrothermally-Actuated Micromirrors with Bimorph Actuators—Bending-Type and Torsion-Type

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Cheng-Hua Tsai

2015-06-01

Full Text Available Three different electrothermally-actuated MEMS micromirrors with Cr/Au-Si bimorph actuators are proposed. The devices are fabricated with the SOIMUMPs process developed by MEMSCAP, Inc. (Durham, NC, USA. A silicon-on-insulator MEMS process has been employed for the fabrication of these micromirrors. Electrothermal actuation has achieved a large angular movement in the micromirrors. Application of an external electric current 0.04 A to the bending-type, restricted-torsion-type, and free-torsion-type mirrors achieved rotation angles of 1.69°, 3.28°, and 3.64°, respectively.

Convective mass transfer in helical pipes: effect of curvature and torsion

Energy Technology Data Exchange (ETDEWEB)

Litster, S.; Djilali, N. [University of Victoria, Department of Mechanical Engineering, Victoria, BC (Canada); Pharoah, J.G. [University of Victoria, Department of Mechanical Engineering, Victoria, BC (Canada); Queen' s University at Kingston, Department of Mechanical Engineering, Kingston, ON (Canada)

2006-03-01

A 3D numerical analysis of the flow and mass transfer in helical pipes is presented. The interpretation of the flow patterns and their impact on mass transfer is shown to require a non-orthogonal pseudo-stream function based visualization. The strong coupling between torsion and curvature effects, and the resulting secondary flow regimes are well characterized by a parameter combining both the Dean (Dn) and Germano numbers (Gn). For membrane separation applications, helical modules combining high curvature with low torsion would alleviate concentration polarization and yield appreciable flux improvement. (orig.)

Observation and control of coherent torsional dynamics in a quinquethiophene molecule.

Science.gov (United States)

Cirmi, Giovanni; Brida, Daniele; Gambetta, Alessio; Piacenza, Manuel; Della Sala, Fabio; Favaretto, Laura; Cerullo, Giulio; Lanzani, Guglielmo

2010-07-28

By applying femtosecond pump-probe spectroscopy to a substituted quinquethiophene molecule in solution, we observe in the time domain the coherent torsional dynamics that drives planarization of the excited state. Our interpretation is based on numerical modeling of the ground and excited state potential energy surfaces and simulation of wavepacket dynamics, which reveals two symmetric excited state deactivation pathways per oscillation period. We use the acquired knowledge on torsional dynamics to coherently control the excited state population with a pump-dump scheme, exploiting the non-stationary Franck-Condon overlap between ground and excited states.

An unusual case of intra-abdominal testicular torsion: Role of laparoscopy

Directory of Open Access Journals (Sweden)

Alfonso Papparella

2013-01-01

Full Text Available The authors report a case of intra-abdominal testicular torsion, where laparoscopy has been useful for diagnosis and surgical management. A boy was presented with a left impalpable testis. Laparoscopy revealed a twisted spermatic cord at the inlet pelvis, which ended in a testicular remnant located in the sub-umbilical area. After orchiectomy, the pathologist confirmed testicular atrophy. Diagnosis of intra-abdominal testicular torsion should be considered in patients with impalpable testis and abdominal pain, but could not be excluded in those with no symptoms.

MDM2 Antagonists Counteract Drug-Induced DNA Damage

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Anna E. Vilgelm

2017-10-01

Full Text Available Antagonists of MDM2-p53 interaction are emerging anti-cancer drugs utilized in clinical trials for malignancies that rarely mutate p53, including melanoma. We discovered that MDM2-p53 antagonists protect DNA from drug-induced damage in melanoma cells and patient-derived xenografts. Among the tested DNA damaging drugs were various inhibitors of Aurora and Polo-like mitotic kinases, as well as traditional chemotherapy. Mitotic kinase inhibition causes mitotic slippage, DNA re-replication, and polyploidy. Here we show that re-replication of the polyploid genome generates replicative stress which leads to DNA damage. MDM2-p53 antagonists relieve replicative stress via the p53-dependent activation of p21 which inhibits DNA replication. Loss of p21 promoted drug-induced DNA damage in melanoma cells and enhanced anti-tumor activity of therapy combining MDM2 antagonist with mitotic kinase inhibitor in mice. In summary, MDM2 antagonists may reduce DNA damaging effects of anti-cancer drugs if they are administered together, while targeting p21 can improve the efficacy of such combinations.

Fluid dynamics, cavitation, and tip-to-tissue interaction of longitudinal and torsional ultrasound modes during phacoemulsification.

Science.gov (United States)

Zacharias, Jaime; Ohl, Claus-Dieter

2013-04-01

To describe the fluidic events that occur in a test chamber during phacoemulsification with longitudinal and torsional ultrasound (US) modalities. Pasteur Ophthalmic Clinic Phacodynamics Laboratory, Santiago, Chile, and Nanyang Technological University, Singapore. Experimental study. Ultra-high-speed videos of a phacoemulsifying tip were recorded while the tip operated in longitudinal and torsional US modalities using variable US power. Two high-speed video cameras were used to record videos up to 625,000 frames per second. A high-intensity spotlight source was used for illumination to engage shadowgraphy techniques. Particle image velocimetry was used to evaluate fluidic patterns while a hyperbaric environmental system allowed the evaluation of cavitation effects. Tip-to-tissue interaction at high speed was evaluated using human cataract fragments. Particle imaging velocimetry showed the following flow patterns for longitudinal and torsional modes at high US powers: forward-directed streaming with longitudinal mode and backward-directed streaming with torsional mode. The ultrasound power threshold for the appearance of cavitation was 60% for longitudinal mode and 80% for torsional mode. Cavitation was suppressed with pressure of 1.0 bar for longitudinal mode and 0.3 bar for torsional mode. Generation of previously unseen stable gaseous microbubbles was noted. Tip-to-tissue interaction analysis showed the presence of cavitation bubbles close to the site of fragmentation with no apparent effect on cutting. High-speed imaging and particle image velocimetry yielded a better understanding and differentiated the fluidic pattern behavior between longitudinal and torsional US during phacoemulsification. These recordings also showed more detailed aspects of cavitation that clarified its role in lens material cutting for both modalities. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Isolated tubal torsion: Successful preoperative diagnosis of five cases using ultrasound and management with laparoscopy

Directory of Open Access Journals (Sweden)

Erdem Fadıloğlu

2017-09-01

Full Text Available Our aim was to evaluate the presentation and diagnostic evaluation of patients with isolated tubal torsion and to evaluate the surgical approach to these patients. We also aimed to define the ultrasonographic diagnostic criteria. Five patients with isolated tubal torsion who were admitted to our gynecology department between January 2014 and January 2017 were evaluated and included in this study. All cases were diagnosed through ultrasonographic imaging alone. The preoperative findings of the patients were similar to those described in the literature. No further imaging modality was used for diagnosis and all patients were managed with laparoscopy. The clinical findings and ultrasonographic findings were consistent with literature. It may be difficult to preoperatively diagnose isolated tubal torsion, which is a rare clinical entity. Evaluation of these patients by an experienced sonographer and knowledge of the ultrasonographic findings of isolated tubal torsion may have vital preventive measures.

Torsion, infarction, and rupture of a nongravid uterus: a complication of a large ovarian cyst.

Science.gov (United States)

Yap, Felix Y; Radin, Randall; Tchelepi, Hisham

2016-12-01

Torsion of a nongravid uterus is rare, as most cases of uterine torsion occur during pregnancy. We report a case of a large ovarian cyst causing uterine torsion, infarction, and rupture. A 57-year-old woman presented with acute-onset abdominal pain and increasing abdominal girth over the past year. Contrast-enhanced computed tomography (CT) demonstrated axial rotation and swirling of the uterus and the mesenteric fat, leading to a preoperative diagnosis of uterine torsion. Laparotomy confirmed that the uterine corpus had undergone a 180-degree axial rotation, and further revealed uterine wall infarction and rupture into the endometrium as well as partial decapitation of the uterus from the cervix. The swirled appearance of the uterus, radiologically similar to the "whirlpool sign" seen in bowel volvulus, is an important CT finding to recognize, especially in view of the risk of irreversible ischemic complications this uncommon entity may inflict on the uterus.

The comparison between torsional and conventional mode phacoemulsification in moderate and hard cataracts.

Science.gov (United States)

Kim, Dong-Hyun; Wee, Won-Ryang; Lee, Jin-Hak; Kim, Mee-Kum

2010-12-01

To compare the intraoperative performances and postoperative outcomes of cataract surgery performed with longitudinal phacoemulsification and torsional phacoemulsification in moderate and hard cataracts. Of 85 patients who had senile cataracts, 102 eyes were operated on using the Infiniti Vision System. Preoperative examinations (slit lamp examination, mean central corneal thickness, and central endothelial cell counts) were performed for each patient. Cataracts were subdivided into moderate and hard, according to the Lens Opacities Classification System III grading of nucleus opalescence (NO). Eyes in each cataract group were randomly assigned to conventional and torsional phaco-mode. Intraoperative parameters, including ultrasound time (UST), cumulative dissipated energy (CDE), and the balanced salt solution plus (BSSP) volume utilized were evaluated. Best corrected visual acuity (BCVA) was checked on postoperative day 30; mean central corneal thickness and central endothelial cell counts were investigated on postoperative days 7 and 30. Preoperative BCVA and mean grading of NO showed no difference in both groups. Preoperative endothelial cell count and central corneal thickness also showed no significant difference in both groups. In the moderate cataract group, the CDE, UST, and BSSP volume were significantly lower in the torsional mode than the longitudinal mode, but they did not show any difference in the hard cataract group. Torsional group showed less endothelial cell loss and central corneal thickening at postoperative day seven in moderate cataracts but showed no significant differences, as compared with the longitudinal group, by postoperative day 30. Torsional phacoemulsification showed superior efficiency for moderate cataracts, as compared with longitudinal phacoemulsification, in the early postoperative stage.

The Comparison between Torsional and Conventional Mode Phacoemulsification in Moderate and Hard Cataracts

Science.gov (United States)

Kim, Dong-Hyun; Wee, Won-Ryang; Lee, Jin-Hak

2010-01-01

Purpose To compare the intraoperative performances and postoperative outcomes of cataract surgery performed with longitudinal phacoemulsification and torsional phacoemulsification in moderate and hard cataracts. Methods Of 85 patients who had senile cataracts, 102 eyes were operated on using the Infiniti Vision System. Preoperative examinations (slit lamp examination, mean central corneal thickness, and central endothelial cell counts) were performed for each patient. Cataracts were subdivided into moderate and hard, according to the Lens Opacities Classification System III grading of nucleus opalescence (NO). Eyes in each cataract group were randomly assigned to conventional and torsional phaco-mode. Intraoperative parameters, including ultrasound time (UST), cumulative dissipated energy (CDE), and the balanced salt solution plus (BSSP) volume utilized were evaluated. Best corrected visual acuity (BCVA) was checked on postoperative day 30; mean central corneal thickness and central endothelial cell counts were investigated on postoperative days 7 and 30. Results Preoperative BCVA and mean grading of NO showed no difference in both groups. Preoperative endothelial cell count and central corneal thickness also showed no significant difference in both groups. In the moderate cataract group, the CDE, UST, and BSSP volume were significantly lower in the torsional mode than the longitudinal mode, but they did not show any difference in the hard cataract group. Torsional group showed less endothelial cell loss and central corneal thickening at postoperative day seven in moderate cataracts but showed no significant differences, as compared with the longitudinal group, by postoperative day 30. Conclusions Torsional phacoemulsification showed superior efficiency for moderate cataracts, as compared with longitudinal phacoemulsification, in the early postoperative stage. PMID:21165231

Stress Relaxation Of Superelastic Shape Memory Alloy Under Bending And Torsional Load

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Sakib Tanvir

2017-04-01

Full Text Available Stress Relaxation of Superelastic Shape memory NiTi Alloy under bending and torsion is uncommon in literature. Therefore experimental set up has been devised and test results are obtained for superelastic SMA.Unlike the other common engineering materials superelastic SMA it gives dramatic reduction in stress. In this paper therefore results of stress relaxation of superelastic shape memory alloy under bending and torsion are presented graphically and interpreted in terms of stress induced martensitic transformation.

On the physical interpretation of torsion-rotation parameters in methanol and acetaldehyde: Comparison of global fit and ab initio results

International Nuclear Information System (INIS)

Xu, L.; Lees, R.M.; Hougen, J.T.

1999-01-01

Equilibrium structural constants and certain torsion endash rotation interaction parameters have been determined for methanol and acetaldehyde from ab initio calculations using GAUSSIAN 94. The substantial molecular flexing which occurs in going from the bottom to the top of the torsional potential barrier can be quantitatively related to coefficients of torsion endash rotation terms having a (1-cos ampersand hthinsp;3γ) dependence on torsional angle γ. The barrier height, six equilibrium structural constants characterizing the bottom of the potential well, and six torsion endash rotation constants are all compared to experimental parameters obtained from global fits to large microwave and far-infrared data sets for methanol and acetaldehyde. The rather encouraging agreement between the Gaussian and global fit results for methanol seems both to validate the accuracy of ab initio calculations of these parameters, and to demonstrate that the physical origin of these torsion endash rotation interaction terms in methanol lies primarily in structural relaxation with torsion. The less satisfactory agreement between theory and experiment for acetaldehyde requires further study. copyright 1999 American Institute of Physics

A coupled two-dimensional main chain torsional potential for protein dynamics: generation and implementation.

Science.gov (United States)

Li, Yongxiu; Gao, Ya; Zhang, Xuqiang; Wang, Xingyu; Mou, Lirong; Duan, Lili; He, Xiao; Mei, Ye; Zhang, John Z H

2013-09-01

Main chain torsions of alanine dipeptide are parameterized into coupled 2-dimensional Fourier expansions based on quantum mechanical (QM) calculations at M06 2X/aug-cc-pvtz//HF/6-31G** level. Solvation effect is considered by employing polarizable continuum model. Utilization of the M06 2X functional leads to precise potential energy surface that is comparable to or even better than MP2 level, but with much less computational demand. Parameterization of the 2D expansions is against the full main chain torsion space instead of just a few low energy conformations. This procedure is similar to that for the development of AMBER03 force field, except unique weighting factor was assigned to all the grid points. To avoid inconsistency between quantum mechanical calculations and molecular modeling, the model peptide is further optimized at molecular mechanics level with main chain dihedral angles fixed before the calculation of the conformational energy on molecular mechanical level at each grid point, during which generalized Born model is employed. Difference in solvation models at quantum mechanics and molecular mechanics levels makes this parameterization procedure less straightforward. All force field parameters other than main chain torsions are taken from existing AMBER force field. With this new main chain torsion terms, we have studied the main chain dihedral distributions of ALA dipeptide and pentapeptide in aqueous solution. The results demonstrate that 2D main chain torsion is effective in delineating the energy variation associated with rotations along main chain dihedrals. This work is an implication for the necessity of more accurate description of main chain torsions in the future development of ab initio force field and it also raises a challenge to the development of quantum mechanical methods, especially the quantum mechanical solvation models.

Effects of torsional deformation on the microstructures and mechanical properties of a CoCrFeNiMo0.15 high-entropy alloy

Science.gov (United States)

Wu, Wenqian; Guo, Lin; Liu, Bin; Ni, Song; Liu, Yong; Song, Min

2017-12-01

The effects of torsional deformation on the microstructures and mechanical properties of a CoCrFeNiMo0.15 high-entropy alloy have been investigated. The torsional deformation generates a gradient microstructure distribution due to the gradient torsional strain. Both dislocation activity and deformation twinning dominated the torsional deformation process. With increasing the torsional equivalent strain, the microstructural evolution can be described as follows: (1) formation of pile-up dislocations parallel to the trace of {1 1 1}-type slip planes; (2) formation of Taylor lattices; (3) formation of highly dense dislocation walls; (3) formation of microbands and deformation twins. The extremely high deformation strain (strained to fracture) results in the activation of wavy slip. The tensile strength is very sensitive to the torsional deformation, and increases significantly with increasing the torsional angle.

Torsional Newton-Cartan geometry and the Schrodinger algebra

NARCIS (Netherlands)

Bergshoeff, Eric A.; Hartong, Jelle; Rosseel, Jan

2015-01-01

We show that by gauging the Schrodinger algebra with critical exponent z and imposing suitable curvature constraints, that make diffeomorphisms equivalent to time and space translations, one obtains a geometric structure known as (twistless) torsional Newton-Cartan geometry (TTNC). This is a version

Two methods for damping torsional vibrations in DFIG-based wind generators using power converters

Science.gov (United States)

Zhao, Zuyi; Lu, Yupu; Xie, Da; Yu, Songtao; Wu, Wangping

2017-01-01

This paper proposes novel damping control algorithms by using static synchronous compensator (STATCOM) and energy storage system (ESS) to damp torsional vibrations in doubly fed induction generator (DFIG) based wind turbine systems. It first analyses the operating characteristics of STATCOM and ESS for regulating power variations to increase grid voltage stability. Then, new control strategies for STATCOM and ESS are introduced to damp the vibrations. It is followed by illustration of their effectiveness to damp the drive train torsional vibrations of wind turbines, which can be caused by grid disturbances, such as voltage sags and frequency fluctuations. Results suggest that STATCOM is a promising technology to mitigate the torsional vibrations caused by grid voltage sags. By contrast, the ESS connected to the point of common coupling (PCC) of wind turbine systems shows even obvious advantages because of its capability of absorbing/releasing both active and reactive power. It can thus be concluded that STATCOM is useful for stabilizing power system voltage fluctuations, and ESS is more effective both in regulating PCC voltage fluctuations and damping torsional vibrations caused by grid voltage frequency fluctuations.

On discrete symmetries and torsion homology in F-theory

Energy Technology Data Exchange (ETDEWEB)

Mayrhofer, Christoph [Arnold-Sommerfeld-Center, Ludwig-Maximilians-Universität München,München (Germany); Palti, Eran; Till, Oskar; Weigand, Timo [Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg,Heidelberg (Germany)

2015-06-04

We study the relation between discrete gauge symmetries in F-theory compactifications and torsion homology on the associated Calabi-Yau manifold. Focusing on the simplest example of a ℤ{sub 2} symmetry, we show that there are two physically distinct ways that such a discrete gauge symmetry can arise. First, compactifications of M-Theory on Calabi-Yau threefolds which support a genus-one fibration with a bi-section are known to be dual to six-dimensional F-theory vacua with a ℤ{sub 2} gauge symmetry. We show that the resulting five-dimensional theories do not have a ℤ{sub 2} symmetry but that the latter emerges only in the F-theory decompactification limit. Accordingly the genus-one fibred Calabi-Yau manifolds do not exhibit torsion in homology. Associated to the bi-section fibration is a Jacobian fibration which does support a section. Compactifying on these related but distinct varieties does lead to a ℤ{sub 2} symmetry in five dimensions and, accordingly, we find explicitly an associated torsion cycle. We identify the expected particle and membrane system of the discrete symmetry in terms of wrapped M2 and M5 branes and present a field-theory description of the physics for both cases in terms of circle reductions of six-dimensional theories. Our results and methods generalise straightforwardly to larger discrete symmetries and to four-dimensional compactifications.

Lateral-Torsional Buckling Instability Caused by Individuals Walking on Wood Composite I-Joists

Science.gov (United States)

Villasenor Aguilar, Jose Maria

Recent research has shown that a significant number of the falls from elevation occur when laborers are working on unfinished structures. Workers walking on wood I-joists on roofs and floors are prone to fall hazards. Wood I-joists have been replacing dimension lumber for many floor systems and a substantial number of roof systems in light-frame construction. Wood I-joists are designed to resist axial stresses on the flanges and shear stresses on the web while minimizing material used. However, wood I-joists have poor resistance to applied lateral and torsional loads and are susceptible to lateral-torsional buckling instability. Workers walking on unbraced or partially braced wood I-joists can induce axial and lateral forces as well as twist. Experimental testing demonstrated that workers cause lateral-torsional buckling instability in wood I-joists. However, no research was found related to the lateral-torsional buckling instability induced by individuals walking on the wood I-joists. Furthermore, no research was found considering the effects of the supported end conditions and partial bracing in the lateral-torsional buckling instability of wood I-joists. The goal of this research was to derive mathematical models to predict the dynamic lateral-torsional buckling instability of wood composite I-joists loaded by individuals walking considering different supported end conditions and bracing system configurations. The dynamic lateral-torsional buckling instability was analyzed by linearly combining the static lateral-torsional buckling instability with the lateral bending motion of the wood Ijoists. Mathematical models were derived to calculate the static critical loads for the simply supported end condition and four wood I-joist hanger supported end conditions. Additionally, mathematical models were derived to calculate the dynamic maximum lateral displacements and positions of the individual walking on the wood Ijoists for the same five different supported end

The fracture strength by a torsion test at the implant-abutment interface.

Science.gov (United States)

Watanabe, Fumihiko; Hiroyasu, Kazuhiko; Ueda, Kazuhiko

2015-12-01

Fractured connections between implants and implant abutments or abutment screws are frequently encountered in a clinical setting. The purpose of this study was to investigate fracture strength using a torsion test at the interface between the implant and the abutment. Thirty screw-type implant with diameters of 3.3, 3.8, 4.3, 5.0, and 6.0 mm were submitted to a torsion test. Implants of each size were connected to abutments with abutment screws tightened to 20 N · cm. Mechanical stress was applied with a rotational speed of 3.6 °/min until fracture occurred, and maximum torque (fracture torque) and torsional yield strength were measured. The mean values were calculated and then compared using Tukey's test. The abutments were then removed, and the implant-abutment interfaces were examined using a scanning electron microscope (SEM). No significant differences in mean fracture torque were found among 3.3, 3.8, and 4.3 mm-diameter implants, but significant differences were found between these sizes and 5.0 and 6.0 mm-diameter implants (p abutment corresponding to the internal notches of the implant body had been destroyed. Smaller diameter implants demonstrated lower fracture torque and torsional yield strength than implants with larger diameters. In internal tube-in-tube connections, three abutment projections corresponding to rotation-prevention notches were destroyed in each implant.

Tuned dynamics stabilizes an idealized regenerative axial-torsional model of rotary drilling

Science.gov (United States)

Gupta, Sunit K.; Wahi, Pankaj

2018-01-01

We present an exact stability analysis of a dynamical system idealizing rotary drilling. This system comprises lumped parameter axial-torsional modes of the drill-string coupled via the cutting forces and torques. The kinematics of cutting is modeled through a functional description of the cut surface which evolves as per a partial differential equation (PDE). Linearization of this model is straightforward as opposed to the traditional state-dependent delay (SDDE) model and both the approaches result in the same characteristic equation. A systematic study on the key system parameters influencing the stability characteristics reveals that torsional damping is very critical and stable drilling is, in general, not possible in its absence. The stable regime increases as the natural frequency of the axial mode approaches that of the torsional mode and a 1:1 internal resonance leads to a significant improvement in the system stability. Hence, from a practical point of view, a drill-string with 1:1 internal resonance is desirable to avoid vibrations during rotary drilling. For the non-resonant case, axial damping reduces the stable range of operating parameters while for the resonant case, an optimum value of axial damping (equal to the torsional damping) results in the largest stable regime. Interestingly, the resonant (tuned) system has a significant parameter regime corresponding to stable operation even in the absence of damping.

Torsion of Atypical Meckel’s Diverticulum Treated by Laparoscopic-Assisted Surgery

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Atsushi Kohga

2017-01-01

Full Text Available Introduction. Meckel’s diverticulum (MD is the most common congenital anomaly of the intestine, with an incidence of 2~4%. Of those, only 2% of patients with MD are symptomatic. Torsion of MD is extremely rare, and only a dozen cases have been previously reported. Case Report. The patient was a 49-year-old male who presented to our emergency room with a chief complaint of lower abdominal pain. Computed tomography imaging revealed an irregular polycystic mass connected to the small intestine that measured 7.5 cm in a diameter. A laparoscopic-assisted partial resection of the jejunum was performed. The lesion was found to have caused torsion and was located 130 cm from the ileocecal valve. The specimen was polycystic in appearance and showed communicating links with the submucosal layer of jejunum but not with the lumen. The pathological diagnosis was a torsion of an atypical presentation of MD. Conclusion. This case was different from typical cases of MD in that it was located on significantly oral side and had the appearance of polycystic morphology.

Total curvature and total torsion of knotted random polygons in confinement

Science.gov (United States)

Diao, Yuanan; Ernst, Claus; Rawdon, Eric J.; Ziegler, Uta

2018-04-01

Knots in nature are typically confined spatially. The confinement affects the possible configurations, which in turn affects the spectrum of possible knot types as well as the geometry of the configurations within each knot type. The goal of this paper is to determine how confinement, length, and knotting affect the total curvature and total torsion of random polygons. Previously published papers have investigated these effects in the unconstrained case. In particular, we analyze how the total curvature and total torsion are affected by (1) varying the length of polygons within a fixed confinement radius and (2) varying the confinement radius of polygons with a fixed length. We also compare the total curvature and total torsion of groups of knots with similar complexity (measured as crossing number). While some of our results fall in line with what has been observed in the studies of the unconfined random polygons, a few surprising results emerge from our study, showing some properties that are unique due to the effect of knotting in confinement.

Predisposing factors for colonic torsion/volvulus in dogs: a retrospective study of six cases (1992-2010).

Science.gov (United States)

Gagnon, Dominique; Brisson, Brigitte

2013-01-01

The purposes of this retrospective study were to review cases of colonic torsion/volvulus between July 1992 and August 2010 and to determine if any predisposing factors exist for the development of this condition. Six dogs were diagnosed with colonic torsion/volvulus during the study period. Four dogs had a history of previous gastric dilation-volvulus (GDV) with prophylactic gastropexy. Three of six dogs diagnosed with colonic torsion/volvulus had large intestinal entrapment and strangulation around the gastropexy site at the time of surgery. The history, clinical signs, physical examination, and radiologic findings were not specific for colonic torsion/volvulus in any dog. Early exploratory laparotomy was indicated to confirm the diagnosis and perform surgical correction of the affected bowel segments. Three of five dogs that underwent surgery had a left abdominal wall colopexy performed. All five dogs that underwent surgery in this study survived postoperatively. One patient was euthanized without surgical intervention. Results suggest that colonic torsion/volvulus should be considered in any large-breed dog with nonspecific gastrointestinal clinical signs and a history of previous gastropexy. Early recognition and prompt treatment of this condition may result in a good outcome.

Femoral Shaft Torsion in Injured and Uninjured Ballet Dancers and Its Association with Other Hip Measures: A Cross-sectional Study.

Science.gov (United States)

Hafiz, Eliza; Hiller, Claire E; Nicholson, Leslie L; Nightingale, Elizabeth J; Grimaldi, Alison; Refshauge, Kathryn M

2016-03-01

Low range femoral torsion, termed "lateral shaft torsion," has been associated with greater range of hip external rotation and turnout in dancers. It is also hypothesized that achieving greater turnout at the hip minimizes torsion at the knee, shank, ankle, and foot, and consequently reduces incidence of lower limb injuries. The primary aims of this study were to investigate: 1. differences in range of femoral shaft torsion between dancers with and without lower limb injuries; and 2. the relationship between femoral shaft torsion, hip external rotation range, and turnout. A secondary aim was to examine the relationship between femoral shaft torsion and other hip measures: hip strength, lower limb joint hypermobility, hip stability, and foot progression angle, as explanatory variables. Demographic, dance, and injury data were collected, along with physical measures of femoral shaft torsion, hip rotation range of motion, and turnout. Hip strength, control, lower limb hypermobility, and foot progression angle were also measured. Eighty female dancers, 50 with lower limb injury (20.7 ± 4.8 years of age) and 30 without lower limb injury (17.8 ± 4.1 years of age), participated in the study. There was no difference in range of femoral shaft torsion between the groups (p = 0.941). Femoral shaft torsion was weakly correlated with range of hip external rotation (r = -0.034, p = 0.384) and turnout (r = -0.066, p = 0.558). Injured dancers had a significantly longer training history than non-injured dancers (p = 0.001). It was concluded that femoral shaft torsion does not appear to be associated with the overall incidence of lower limb injury in dancers or to be a primary factor influencing extent of turnout in this population.

MR evaluation of femoral neck version and tibial torsion

Energy Technology Data Exchange (ETDEWEB)

Koenig, James Karl; Dwek, Jerry R. [University of California, San Diego, Children' s Hospital and Health Center, Department of Radiology, San Diego, CA (United States); Pring, Maya E. [Rady Children' s Hospital, Department of Pediatric Orthopedic Surgery, San Diego, CA (United States)

2012-01-15

Abnormalities of femoral neck version have been associated with a number of hip abnormalities in children, including slipped capital femoral epiphysis, proximal femoral focal deficiency, coxa vara, a deep acetabulum and, rarely, developmental dysplasia of the hip. Orthopedic surgeons also are interested in quantifying the femoral neck anteversion or retroversion in children especially to plan derotational osteotomies. Historically, the angle of femoral version and tibial torsion has been measured with the use of radiography and later by CT. Both methods carry with them the risks associated with ionizing radiation. Techniques that utilize MR are used less often because of the associated lengthy imaging times. This article describes a technique using MRI to determine femoral neck version and tibial torsion with total scan times of approximately 10 min. (orig.)

Direct observation of vibrational energy dispersal via methyl torsions.

Science.gov (United States)

Gardner, Adrian M; Tuttle, William D; Whalley, Laura E; Wright, Timothy G

2018-02-28

Explicit evidence for the role of methyl rotor levels in promoting energy dispersal is reported. A set of coupled zero-order vibration/vibration-torsion (vibtor) levels in the S 1 state of para -fluorotoluene ( p FT) are investigated. Two-dimensional laser-induced fluorescence (2D-LIF) and two-dimensional zero-kinetic-energy (2D-ZEKE) spectra are reported, and the assignment of the main features in both sets of spectra reveals that the methyl torsion is instrumental in providing a route for coupling between vibrational levels of different symmetry classes. We find that there is very localized, and selective, dissipation of energy via doorway states, and that, in addition to an increase in the density of states, a critical role of the methyl group is a relaxation of symmetry constraints compared to direct vibrational coupling.

Conformal deformation of Riemann space and torsion

International Nuclear Information System (INIS)

Pyzh, V.M.

1981-01-01

Method for investigating conformal deformations of Riemann spaces using torsion tensor, which permits to reduce the second ' order equations for Killing vectors to the system of the first order equations, is presented. The method is illustrated using conformal deformations of dimer sphere as an example. A possibility of its use when studying more complex deformations is discussed [ru

Model-based analysis and control of axial and torsional stick-slip oscillations in drilling systems

NARCIS (Netherlands)

Besselink, B.; Wouw, van de N.; Nijmeijer, H.

2011-01-01

The mechanisms leading to torsional vibrations in drilling systems are considered in this paper. Thereto, a drill string model of the axial and torsional dynamics is proposed, where coupling is provided by a rate-independent bit-rock interaction law. Analysis of this model shows that the fast axial

Corneal endothelial morphology and function after torsional and longitudinal ultrasound mode phacoemulsification.

Science.gov (United States)

Módis, László Jr; Szalai, Eszter; Flaskó, Zsuzsa; Németh, Gábor

2016-01-01

To study the endothelial cell morphology and corneal thickness changes after phacoemulsification by using the OZil torsional and longitudinal ultrasound techniques (Infiniti Vision System, Alcon Laboratories). Department of Ophthalmology, Clinical Center, University of Debrecen, Debrecen, Hungary. 52 patients with cataract were randomly assigned to longitudinal ultrasound and torsional mode group. All surgeries were performed through a 2.2 mm clear corneal incision, the method employed being divide and conquer. The endothelial morphometry such as cell density (ECD), mean cell area, coefficient of variation of cell area, and central corneal thickness were examined with specular microscopy (EM-1000, Tomey) preoperatively and 4, 8 weeks postoperatively. ECD values decreased significantly in both surgical groups (P .05). No significant correlation was found between the endothelial cell loss and the nucleus density. Both phacoemulsification techniques were safe and effective. The torsional handpiece performs oscillatory movements and delivers less energy into the eye than the longitudinal ultrasound technique, therefore providing more favorable energy and thermal safety profile.

Cocaine abuse that presents with acute scrotal pain and mimics testicular torsion

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José Tadeu Nunes Tamanini

Full Text Available ABSTRACT Report case (s relevant aspects: Man, 27 years old, complaining of acute testicular pain by 2 hours in the remaining left testicle. Denies fever, lower urinary tract symptoms such as dysuria, urinary frequency, concommitant or prior urethral discharge to the painful condition. He underwent right orchiectomy 13 years ago by testicular torsion. He is a chronic user of cocaine for 15 years and during the last three days the drug use was continuous and intense. Proposed premise substantiating case (s description: Initial diagnostic hypothesis: Syndromic: Acute Scrotum Syndrome (SEA Main Etiologic (testicular torsion Secondary Etiologic (acute orchiepididymitis Briefly delineates what might it add? Lines of research That Could be Addressed: In this challenging clinical case we presented an alternative and new etiologic diangosis for the acute scrotum which the main etiologic factor remains testicular torsion. This new diangosis is acute testicular ischemia as a complication of cocaine abuse.

Acute Primary Haemorrhagic Omental Torsion Mimicking Perforated Appendicitis: An Unorthodox Surgical Paradox

International Nuclear Information System (INIS)

Rehman, A.

2014-01-01

Acute primary haemorrhagic omental torsion is an atypical and deceptive cause of acute abdomen that could closely mimic a myriad of intra-abdominal catastrophes, especially perforated appendicitis. The author reports a 30 years man who had presented with gradually worsening right-sided abdominal pain of 2 days duration. Laboratory work-up and abdominal radiographs were inconclusive. Abdominal sonography detected presence of free fluid in the pelvic cul-de-sac. Based on clinical and sonographic findings, presumptive diagnosis of perforated appendicitis was made and the patient was explored through extended Rockey-Davis incision. About 500 - 700 ml of dark-coloured blood (haemoperitoneum) was present in the peritoneal cavity and the pelvis secondary to acute haemorrhagic omental torsion. The appendix was grossly normal. Omentectomy and prophylactic appendicectomy resulted in uneventful recovery of the patient. Acute primary omental torsion is an uncommon pathology that must be kept in mind during differential diagnosis of acute abdomen, especially acute or perforated appendicitis. (author)

Ab initio calculations of torsionally mediated hyperfine splittings in E states of acetaldehyde

Science.gov (United States)

Xu, Li-Hong; Reid, E. M.; Guislain, B.; Hougen, J. T.; Alekseev, E. A.; Krapivin, I.

2017-12-01

Quantum chemistry packages can be used to predict with reasonable accuracy spin-rotation hyperfine interaction constants for methanol, which contains one methyl-top internal rotor. In this work we use one of these packages to calculate components of the spin-rotation interaction tensor for acetaldehyde. We then use torsion-rotation wavefunctions obtained from a fit to the acetaldehyde torsion-rotation spectrum to calculate the expected magnitude of hyperfine splittings analogous to those observed at relatively high J values in the E symmetry states of methanol. We find that theory does indeed predict doublet splittings at moderate J values in the acetaldehyde torsion-rotation spectrum, which closely resemble those seen in methanol, but that the factor of three decrease in hyperfine spin-rotation constants compared to methanol puts the largest of the acetaldehyde splittings a factor of two below presently available Lamb-dip resolution.

Axial Torsion of Gangrenous Meckel's Diverticulum Causing Small ...

African Journals Online (AJOL)

dividing the band. Resection and anastomosis of the small bowel including the MD was performed. We hereby report a rare and unusual complication of a MD. Although treatment outcome is generally good, pre-operative diagnosis is often difficult. Key words: Axial torsion, Meckel's diverticulum, small bowel obstruction.

Diffusive intergranular cavity growth in creep in tension and torsion

International Nuclear Information System (INIS)

Stanzl, S.E.; Argon, A.S.; Tschegg, E.K.

1983-01-01

Creep experiments were performed at 500 C in tension and torsion on high conductivity copper tubes with a uniform initial coverage of implanted water vapor bubbles on all grain boundaries. No significant differences were found in the times to fracture over a wide stress range when the results were correlated according to the maximum principal tensile stress in the two fields. The results indicate that the cavities grow in a crack-like mode but at one tenth the rate predicted from the theoretical model of Pharr and Nix. This difference is attributed partly to load shedding from boundaries normal to the maximum principal tensile stress to slanted boundaries, and partly to a lack of knowledge about th surface diffusion constant. The results indicate further that the contribution to intergranular cavity growth by power-law creep in negligible in comparison to the contribution by diffusional flow. Complementary tension and torsion experiments performed in initially uncavitated samples results in shorter creep lives in torsion than in tension due to more effective cavity nucleation in the former. The times to fracture in both of these cases obey Monkman and Grant's law, indicating the presence of constraints on growth by the lagging deformations by power-law creep in the surroundings of the cavitating isolated grain facets

Microscopic Features of Fractured Fragment of Nickel-Titanium Endodontic Instruments by Two Different Modes of Torsional Loading

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Ibrahim H. Abu-Tahun

2018-01-01

Full Text Available 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 (0.5 N·cm was applied and the clockwise loading to the preset torque and counterclockwise unloading to original position were repeated at 50 rpm until the file fractured. Fractured fragments by two methods were compared under a scanning electron microscope (SEM to examine the topographic features of the fractured surfaces and longitudinal aspects. SEM examinations showed significantly different features according to the loading methods. Specimens from the RTL method showed ruptured aspects on cross sections, with multiple areas of initiated cracks while the STL method showed the typical features of torsional failure, such as circular abrasion marks and fatigue dimples. This study suggested a new repetitive torsional loading method which is much more clinically relevant and may result in a different fracture feature from STL method.

Cosmology with torsion: An alternative to cosmic inflation

International Nuclear Information System (INIS)

Poplawski, Nikodem J.

2010-01-01

We propose a simple scenario which explains why our Universe appears spatially flat, homogeneous and isotropic. We use the Einstein-Cartan-Kibble-Sciama (ECKS) theory of gravity which naturally extends general relativity to include the spin of matter. The torsion of spacetime generates gravitational repulsion in the early Universe filled with quarks and leptons, preventing the cosmological singularity: the Universe expands from a state of minimum but finite radius. We show that the dynamics of the closed Universe immediately after this state naturally solves the flatness and horizon problems in cosmology because of an extremely small and negative torsion density parameter, Ω S ∼-10 -69 . Thus the ECKS gravity provides a compelling alternative to speculative mechanisms of standard cosmic inflation. This scenario also suggests that the contraction of our Universe preceding the bounce at the minimum radius may correspond to the dynamics of matter inside a collapsing black hole existing in another universe, which could explain the origin of the Big Bang.

Torsion of a growing shaft

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Alexander V. Manzhirov

2017-12-01

Full Text Available The torsion of a shaft by rigid disks is considered. The shaft has the form of circular cylinder. Two rigid disks are attached to its end faces. The process of continuous growth of such shaft under the influence of twisting torques applied to the disks is studied. Dual series equations which reflect the mathematical content of the problem at the different stages of the growing process are derived and solved. Results of the numerical analysis and singularities of the qualitative mechanical behaviour of the fundamental characteristics are discussed.

Ursolic Acid-Regulated Energy Metabolism—Reliever or Propeller of Ultraviolet-Induced Oxidative Stress and DNA Damage?

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Yuan-Hao Lee

2014-08-01

Full Text Available Ultraviolet (UV light is a leading cause of diseases, such as skin cancers and cataracts. A main process mediating UV-induced pathogenesis is the production of reactive oxygen species (ROS. Excessive ROS levels induce the formation of DNA adducts (e.g., pyrimidine dimers and result in stalled DNA replication forks. In addition, ROS promotes phosphorylation of tyrosine kinase-coupled hormone receptors and alters downstream energy metabolism. With respect to the risk of UV-induced photocarcinogenesis and photodamage, the antitumoral and antioxidant functions of natural compounds become important for reducing UV-induced adverse effects. One important question in the field is what determines the differential sensitivity of various types of cells to UV light and how exogenous molecules, such as phytochemicals, protect normal cells from UV-inflicted damage while potentiating tumor cell death, presumably via interaction with intracellular target molecules and signaling pathways. Several endogenous molecules have emerged as possible players mediating UV-triggered DNA damage responses. Specifically, UV activates the PIKK (phosphatidylinositol 3-kinase-related kinase family members, which include DNA-PKcs, ATM (ataxia telangiectasia mutated and mTOR (mammalian target of rapamycin, whose signaling can be affected by energy metabolism; however, it remains unclear to what extent the activation of hormone receptors regulates PIKKs and whether this crosstalk occurs in all types of cells in response to UV. This review focuses on proteomic descriptions of the relationships between cellular photosensitivity and the phenotypic expression of the insulin/insulin-like growth receptor. It covers the cAMP-dependent pathways, which have recently been shown to regulate the DNA repair machinery through interactions with the PIKK family members. Finally, this review provides a strategic illustration of how UV-induced mitogenic activity is modulated by the insulin

New Examples of Torsion-Free Non-unique Product Groups

OpenAIRE

Carter, William

2013-01-01

We give an infinite family of torsion-free groups that do not satisfy the unique product property. For these examples, we also show that each group contains arbitrarily large sets whose square has no uniquely represented element.

Effects of herbal medicine Sijunzi decoction on rabbits after relieving intestinal obstruction

Directory of Open Access Journals (Sweden)

L. Li

2017-09-01

Full Text Available Intestinal obstruction leads to blockage of the movement of intestinal contents. After relieving the obstruction, patients might still suffer with compromised immune function and nutritional deficiency. This study aimed to evaluate the effects of Sijunzi decoction on restoring the immune function and nutritional status after relieving the obstruction. Experimental rabbits (2.5±0.2 kg were randomly divided into normal control group, 2-day intestinal obstruction group, 2-day natural recovery group, 4-day natural recovery group, 2-day treated group, and 4-day treated group. Sijunzi decoction was given twice a day to the treated groups. The concentration of markers was analyzed to evaluate the immune function and nutritional status. The concentration of interleukin-2, immunoglobulins and complement components of the treated groups were significantly higher than the natural recovery group (P<0.05. The levels of CD4+ and CD4+/CD8+ increased then decreased in the treated groups. The levels of tumor necrosis factor-α and CD8+ were significantly lower than the natural recovery group. The level of total protein in the treated groups also increased then decreased after relieving the obstruction. The levels of albumin, prealbumin and insulin-like growth factor-1 were significantly higher in the treated groups than in the natural recovery group (P<0.05. Transferrin level in the treated groups was significantly higher than the obstruction group (P<0.05. Sijunzi decoction can lessen the inflammatory response and improve the nutrition absorption after relieving the obstruction.

Ocular torsion before and after 1 hour centrifugation

NARCIS (Netherlands)

Groen, E.; Graaf, B. de; Bles, W.; Bos, J.E.

1996-01-01

To assess a possible otolith contribution to effects observed following prolonged expo-sure to hyper gravity, we used video-oculography to measure ocular torsion during static and dynamic conditions of lateral body tilt (roll) before and after one hour of centrifugation with a Gx-load of 3G. Static

Ocular torsion before and after 1 hour centrifugation

NARCIS (Netherlands)

Groen, Eric; De Graaf, Bernd; Bles, Willem; Bos, Jelte E.

1996-01-01

To assess a possible otolith contribution to effects observed following prolonged exposure to hypergravity, we used video oculography to measure ocular torsion during static and dynamic conditions of lateral body tilt (roll) before and after t h of centrifugation with a G(x)-load of 3 G. Static tilt

The spectrum of axisymmetric torsional Alfven waves

International Nuclear Information System (INIS)

Sy, W.N.

1977-03-01

The spectrum of axisymmetric torsional Alfven waves propagating in a cylindrical, non-uniform, resistive plasma waveguide has been analysed by a method of singular perturbations. A simple condition has been derived which predicts whether the spectrum is continuous or discrete under given physical conditions. Application of this result to resolve an apparent discrepancy in experimental observations is briefly discussed. (Author)

Outcomes of torsional microcoaxial phacoemulsification performed by 12-degree and 22-degree bent tips.

Science.gov (United States)

Helvacioglu, Firat; Yeter, Celal; Tunc, Zeki; Sencan, Sadik

2013-08-01

To compare the safety and efficacy of Ozil Intelligent Phaco torsional microcoaxial phacoemulsification surgeries performed with 12-degree and 22-degree bent tips using the Infiniti Vision System. Maltepe University School of Medicine Department of Ophthalmology, Istanbul, Turkey. Comparative case series. Eyes were assigned to 2.2 mm microcoaxial phacoemulsification using the torsional mode with a 22-degree bent tip (Group 1) or a 12-degree bent tip (Group 2). The primary outcome measures were ultrasound time (UST), cumulative dissipated energy (CDE), longitudinal and torsional ultrasound (US) amplitudes, mean surgical time, mean volume of balanced salt solution used, and surgical complications. Both groups included 45 eyes. The mean UST, CDE, longitudinal US amplitude, and torsional US amplitude were 65 seconds ± 27.23 (SD), 11.53 ± 6.99, 0.22 ± 0.26, and 42.86 ± 15.64, respectively, in Group 1 and 84 ± 45.04 seconds, 16.68 ± 10.66, 0.48 ± 0.68, and 46.27 ± 14.74, respectively, in Group 2. The mean UST, CDE, and longitudinal amplitudes were significantly lower in Group 1 (P=.003, P=.008, and P=.022, respectively). The mean volume of balanced salt solution was 73.33 ± 28.58 cc in Group 1 and 82.08 ± 26.21 cc in Group 2 (P=.134). Torsional phacoemulsification performed with 22-degree bent tips provided more effective lens removal than 12-degree bent tips, with a lower UST and CDE. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Spermatic Cord Knot: A Clinical Finding in Patients with Spermatic Cord Torsion

Directory of Open Access Journals (Sweden)

Abdullatif Al-Terki

2011-01-01

Full Text Available Pertinent history taking and careful examination often taper the differentials of the acute scrotum; congruently the ability to diagnose acute spermatic cord torsion (SCT when radiological adjuncts are not available is highly imperative. This observational study serves to present a series of 46 cases of spermatic cord torsion whereby we hypothesize the identification of a clinical knot on scrotal examination as an important clinical aid in making a decision to surgical exploration in patients with acute and subacute SCT, especially in centers where imaging resources are unavailable.

Torsion in a gravity theory with SO(k) x SO(d-k) as tangent group

International Nuclear Information System (INIS)

Viswanathan, K.S.; Wong, B.; Simon Fraser Univ., Burnaby, British Columbia

1985-01-01

We consider a d-dimensional theory of gravity where the tangent group is SO(k) x SO(d-k) rather than SO(d) as in riemannian theories. This theory has nonvanishing torsion (which is required if the theory is to yield gauge fields). The torsion is determined consistently in terms of vielbein derivatives. (orig.)

Torsion of the accessory spleen with infarction : CT features in a case report

Energy Technology Data Exchange (ETDEWEB)

Yun, Jung Kyung; Lee, Jun Sik; Kim, Mee Eun; Pyun, Hae Wook; Lee, Il Gi; Lee, Jong Gil; Kim, Hee Jin; Kim, Ik Su [Fatima Hospital, Taegu (Korea, Republic of)

2000-05-01

Torsion of the accessory spleen is a rare entity that can have variable clinical presentations. We report case involving an 11-year-old boy with severe abdominal pain and a mass that was found to be due to infarction of the accessory spleen, which was twisted on its pedicle. CT revealed a low-attenuating mass with peripheral inflammatory changes in the left upper abdomen. The mass was pathologically confirmed as torsion of the accessory spleen with infarction. (author)

A rare cause of acute abdominal pain in children: Isolated tubal torsion; a case series

Directory of Open Access Journals (Sweden)

Yasemin Dere Gunal

2017-06-01

Full Text Available Isolated tubal torsion -a rare cause of acute abdomen in children-is usually difficult to diagnose because of non-specific findings. Surgical salphingectomy is required in delayed diagnosis in most cases. Three sexual inactive adolescents diagnosed in isolated tubal torsion (ITT were discussed for its diagnostic features and surgical management. Laboratory tests and radiological studies including ultrasonography (US, color doppler ultrasound were performed in all patients after evaluation for acute lower abdominal pain in emergency department and they underwent surgical intervention with laparotomy (n:2 and laparoscopy (n:1. One of the patients in this study had salpingectomy. Detorsion of the fallopian tube and cyst excision were performed in the remaining two patients who also had paratubal cysts. There was no recurrence in these patients during the follow-up for 3 and 2 years. The isolated tubal torsion should be kept in mind and early surgical management is essential in order to preserve fallopian tube because of its importance in fertility. Keywords: Fallopian tube, Torsion, Paratubal cyst, Adolescent, Acute abdomen

Temporal discrimination threshold: VBM evidence for an endophenotype in adult onset primary torsion dystonia.

LENUS (Irish Health Repository)

Bradley, D

2012-02-01

Familial adult-onset primary torsion dystonia is an autosomal dominant disorder with markedly reduced penetrance. Most adult-onset primary torsion dystonia patients are sporadic cases. Disordered sensory processing is found in adult-onset primary torsion dystonia patients; if also present in their unaffected relatives this abnormality may indicate non-manifesting gene carriage. Temporal discrimination thresholds (TDTs) are abnormal in adult-onset primary torsion dystonia, but their utility as a possible endophenotype has not been examined. We examined 35 adult-onset primary torsion dystonia patients (17 familial, 18 sporadic), 42 unaffected first-degree relatives of both familial and sporadic adult-onset primary torsion dystonia patients, 32 unaffected second-degree relatives of familial adult-onset primary torsion dystonia (AOPTD) patients and 43 control subjects. TDT was measured using visual and tactile stimuli. In 33 unaffected relatives, voxel-based morphometry was used to compare putaminal volumes between relatives with abnormal and normal TDTs. The mean TDT in 26 control subjects under 50 years of age was 22.85 ms (SD 8.00; 95% CI: 19.62-26.09 ms). The mean TDT in 17 control subjects over 50 years was 30.87 ms (SD 5.48; 95% CI: 28.05-33.69 ms). The upper limit of normal, defined as control mean + 2.5 SD, was 42.86 ms in the under 50 years group and 44.58 ms in the over 50 years group. Thirty out of thirty-five (86%) AOPTD patients had abnormal TDTs with similar frequencies of abnormalities in sporadic and familial patients. Twenty-two out of forty-two (52%) unaffected first-degree relatives had abnormal TDTs with similar frequencies in relatives of sporadic and familial AOPTD patients. Abnormal TDTs were found in 16\\/32 (50%) of second-degree relatives. Voxel-based morphometry analysis comparing 13 unaffected relatives with abnormal TDTs and 20 with normal TDTs demonstrated a bilateral increase in putaminal grey matter in unaffected relatives with abnormal

Creep-fatique interactions in 316 stainless steel under torsional loading

International Nuclear Information System (INIS)

Wei, K.; Dyson, B.F.

1982-01-01

Some fatigue, fatigue with creep dwells and creep tests have been performed in torsion using 316 stainless steel at 600 0 C. As expected from push-pull testing, the introduction of a creep dwell reduced fatigue endurances and changed the fracture from classical transgranular to intergranular. Optical microscopical examination revealed a large number of intergranular cracks concentrated along shear planes, but quantitative assessment identified the importance of creep tensile stresses in crack development. In contrast, little intergranular damage was found after torsion creep, which is consistent with its exhibited buckling mode of failure. It is concluded that reverse plastic strain is the cause of intergranular crack formation in the material and is therefore the primary mechanism of creep-fatigue interaction. (author)

Budesonide/formoterol maintenance and reliever therapy versus conventional best practice

DEFF Research Database (Denmark)

Demoly, Pascal; Louis, Renaud; Søes-Petersen, Ulrik

2009-01-01

Budesonide/formoterol maintenance and reliever therapy (Symbicort SMART) reduces asthma exacerbations and symptoms versus fixed-dose regimens plus short-acting beta(2)-agonists (SABA) in double-blind trials. Information is lacking regarding its effectiveness versus conventional best practice (CBP...

The evaluation of the neck torsion test in subjective examinations of patients with vertigo and/or hearing loss.

Science.gov (United States)

Niewiadomski, Piotr; Zielińska-Bliźniewskaw, Hanna; Miloński, Jarosław; Pietkiewicz, Piotr; Olszewski, Jurek

2015-01-01

The aim of this work was to evaluate the diagnostic value of the neck torsion test in VNG, Doppler ultrasonography and brainstem auditory evoked potentials in patients with vertigo and/or hearing loss due to intracranial vascular malformations. The study covered 47 patients, 30 female and 17 male (mean age, 55.5 years; range, 19-74 years) with vertigo and/or hearing disorders and the asymmetry of vertebral arteries. Each patient underwent a subjective examination, an otolaryngological examination, otoneurological diagnostics, VNG with gaze tracking in the straight ahead position and in the 600 left and right neck torsion, the neck torsion test, audiological diagnostics including I-, III- and V-wave latency of the brainstem evoked potentials in the straight ahead position and the right ear stimulation in the 600 right neck torsion and the left ear stimulation in the neck torsion to the left, Doppler ultrasonography with measuring the diameter of vertebral arteries and the velocity of the blood flow in these vessels with the use of the neck torsion test. In own study, in VNG, the positive neck torsion test was observed in 76.5% of the study patients, while square waves in both directions were found in 46.5% and in one direction in 10.6%. Cervical nystagmus was noticed in 19.1% of these patients. In the auditory evoked potentials test, the differences in I-, III- and V-wave latency time were not statistically significant, either at rest or in the neck torsion. In the Doppler ultrasound examination, the asymmetry of vertebral arteries were present (below 25%) in 7 women (14.9%) and 4 men (8.5%), whereas large asymmetries (above 25%) were observed in 23 women (48.9%) and 13 (27.7%) men (range, 25% - 215%) and was statistically insignificant. The resting blood flow velocity in vertebral arteries of large asymmetries, both in systole and diastole heart phases, was significantly higher in the artery with larger asymmetry. The neck torsion test can be diagnostically useful

Protective effects of udenafil citrate, piracetam and dexmedetomidine treatment on testicular torsion/detorsion-induced ischaemia/reperfusion injury in rats.

Science.gov (United States)

Tuglu, D; Yuvanc, E; Ozan, T; Bal, F; Yilmaz, E; Atasoy, P; Kisa, U; Batislam, E

2016-08-01

The aim of this study was to investigate the antioxidant properties of udenafil citrate (1.4 mg kg(-1) -2.8 mg kg(-1) ), dexmedetomidine 25 μg kg(-1) and piracetam 200 mg kg(-1) administered on ipsilateral/contralateral testes after ischaemia in a rat model of testicular torsion/detorsion (T/D) and define its protective effect histologically. Fifty-six Wistar albino rats were included and randomly assigned into 6 groups. No intervention was performed in control group (Group 1, n = 8) and in torsion/detorsion group, (Group 2, n = 8). Udenafil 1.4 mg kg(-1) was given to torsion/detorsion group (Group 3, n = 10), udenafil 2.8 mg kg(-1) was given to torsion/detorsion group (Group 4, n = 10), piracetam 200 mg kg(-1) was given to torsion/detorsion group (Group 5, n = 10) and dexmedetomidine 25 μg kg(-1) was given to torsion/detorsion group (Group 6, n = 10) intraperitoneally after 60 mins of testicular torsion. Biochemical and histopathological testicular injury were evaluated. When the tissue was examined by TOS values, Group 3, Group 4 and Group 5 were significantly lower than Group 2. In contrary Group 6 values were significantly higher than Group 2. The increasing doses of udenafil demonstrated antioxidant properties on the testis tissue and histopathological that protects the testicles. © 2015 Blackwell Verlag GmbH.

Modeling the Elastic and Damping Properties of the Multilayered Torsion Bar-Blade Structure of Rotors of Light Helicopters of the New Generation 2. Finite-Element Approximation of Blades and a Model of Coupling of the Torsion Bar with the Blades

Science.gov (United States)

Paimushin, V. N.; Shishkin, V. M.

2016-01-01

A rod-shape finite element with twelve degrees of freedom is proposed for modeling the elastic and damping properties of rotor blades with regard to their geometric stiffness caused by rotation of the rotor. A model of coupling of the torsion bar with blades is developed based on the hypothesis of linear deplanation of the connecting section of the torsion bar and a special transition element to ensure the compatibility of displacements of the torsion bar and blades upon their vibrations in the flapping and rotation planes. Numerical experiments were carried out to test and assess the validity of the model developed. Suggestions are made for ensuring unconditional stability of the iteration method in a subspace in determining the specified number of modes and frequencies of free vibrations of the torsion bar-blade structure.

Low-dose biplanar radiography can be used in children and adolescents to accurately assess femoral and tibial torsion and greatly reduce irradiation

Energy Technology Data Exchange (ETDEWEB)

Meyrignac, Olivier; Baunin, Christiane; Vial, Julie; Sans, Nicolas [CHU Toulouse Purpan, Department of Radiology, Toulouse Cedex 9 (France); Moreno, Ramiro [ALARA Expertise, Oberhausbergen (France); Accadbled, Franck; Gauzy, Jerome Sales de [Hopital des Enfants, Department of Orthopedics, Toulouse Cedex 9 (France); Sommet, Agnes [Universite Paul Sabatier, Department of Fundamental Pharmaco-Clinical Pharmacology, Toulouse (France)

2015-06-01

To evaluate in children the agreement between femoral and tibial torsion measurements obtained with low-dose biplanar radiography (LDBR) and CT, and to study dose reduction ratio between these two techniques both in vitro and in vivo. Thirty children with lower limb torsion abnormalities were included in a prospective study. Biplanar radiographs and CTs were performed for measurements of lower limb torsion on each patient. Values were compared using Bland-Altman plots. Interreader and intrareader agreements were evaluated by intraclass correlation coefficients. Comparative dosimetric study was performed using an ionization chamber in a tissue-equivalent phantom, and with thermoluminescent dosimeters in 5 patients. Average differences between CT and LDBR measurements were -0.1 ±1.1 for femoral torsion and -0.7 ±1.4 for tibial torsion. Interreader agreement for LDBR measurements was very good for both femoral torsion (FT) (0.81) and tibial torsion (TT) (0.87). Intrareader agreement was excellent for FT (0.97) and TT (0.89). The ratio between CT scan dose and LDBR dose was 22 in vitro (absorbed dose) and 32 in vivo (skin dose). Lower limb torsion measurements obtained with LDBR are comparable to CT measurements in children and adolescents, with a considerably reduced radiation dose. (orig.)

Discussion on massive gravitons and propagating torsion in arbitrary dimensions

International Nuclear Information System (INIS)

Hernaski, C.A.; Vargas-Paredes, A.A.; Helayel-Neto, J.A.

2009-01-01

Full text. Massive gravity has been an issue of particular interest since the early days of Quantum Gravity. More recently, in connection with models based on brane-world scenarios, the discussion of massive gravitons is drawing a great deal of attention, in view of the possibility of their production at LHC and the feasibility of detection of quantum gravity effects at the TeV scale. In this paper, we reassess a particular R 2 -type gravity action in D dimensions, recently studied by Nakasone and Oda, taking now torsion effects into account. Considering that the vielbein and the spin connection carry independent propagating degrees of freedom, we conclude that ghosts and tachyons are absent only if torsion is non-propagating, and we also conclude that there is no room for massive gravitons. To include these excitations, we understand how to enlarge Nakasone-Oda's model by means of explicit torsion terms in the action and we discuss the unitarity of the enlarged model for arbitrary dimensions. To make this we construct a complete basis of operators that projects the degrees of freedom of the dynamical fields of the model in their irreducible spin decomposition. The outcome is that we find a set of Lagrangians with a massive graviton that, in D=4, reproduce those already studied in the literature. (author)

Overall asthma control achieved with budesonide/formoterol maintenance and reliever therapy for patients on different treatment steps

Directory of Open Access Journals (Sweden)

Östlund Ollie

2011-04-01

Full Text Available Abstract Background Adjusting medication for uncontrolled asthma involves selecting one of several options from the same or a higher treatment step outlined in asthma guidelines. We examined the relative benefit of introducing budesonide/formoterol (BUD/FORM maintenance and reliever therapy (Symbicort SMART® Turbuhaler® in patients previously prescribed treatments from Global Initiative for Asthma (GINA Steps 2, 3 or 4. Methods This is a post hoc analysis of the results of five large clinical trials (>12000 patients comparing BUD/FORM maintenance and reliever therapy with other treatments categorised by treatment step at study entry. Both current clinical asthma control during the last week of treatment and exacerbations during the study were examined. Results At each GINA treatment step, the proportion of patients achieving target levels of current clinical control were similar or higher with BUD/FORM maintenance and reliever therapy compared with the same or a higher fixed maintenance dose of inhaled corticosteroid/long-acting β2-agonist (ICS/LABA (plus short-acting β2-agonist [SABA] as reliever, and rates of exacerbations were lower at all treatment steps in BUD/FORM maintenance and reliever therapy versus same maintenance dose ICS/LABA (P Conclusions BUD/FORM maintenance and reliever therapy may be a preferable option for patients on Steps 2 to 4 of asthma guidelines requiring a more effective treatment and, compared with other fixed dose alternatives, is most effective in the higher treatment steps.

Effect of cyclic torsional preloading on cyclic fatigue resistance of ProTaper Next and Mtwo nickel–titanium instruments

Directory of Open Access Journals (Sweden)

Eugenio Pedullà

2015-06-01

Conclusions: Torsional preloads reduced the cyclic fatigue resistance of M-wire and conventional (as ProTaper Next and Mtwo NiTi rotary instruments except for Mtwo with 25% or 50% of torsional preloading.

Dynamic response of a clamped/free hollow circular cylinder under travelling torsional impact loads

International Nuclear Information System (INIS)

Jonker, J.B.

1982-01-01

Impact-induced vibrations in the casing of a gas centriguge due to a sudden failure of the spinning rotor (crash) can cause structural disintegrity of the casing. In order to study the influence of the rotor failure bahaviour and the impact load histories on the dynamic response of the casing, a simple crash model is proposed in this paper to analyse the transient torsional response due to tangential components of the impact loads. The casing is modeled as a linear-elastic hollow circular cylinder, clamped at the lower end and free at the upper end. The rotor is thought to breakup in identical sections in a sequence determined by its fracture behaviour. Each section is assumed to cause an axi-symmetric load distribution at the inner surface of the casing. Therefore the problem is essentially reduced to the analysis of a clamped/free cylinder under travelling torsional impact loads. The problem is solved by representing the impact loads as local pulses acting over the length of the sections. A perturbation method is used to show that the general two-dimensional theory of axi-symmetric torsional wave propagation in circular cylinders, for the problem under consideration, may be approximated by the elementary one-dimensional theory. Solutions are obtained according to the usual modal expansion approach. Measurements of transient torsional responses are shown to be in good agreement with the calculated responses by choosing a suitable shape of the pulses. The effects of travelling velocity and pulse shape are investigated. Finally the transfer of kinetic energy in the rotor to vibrational energy of torsion in the casing is studied. (orig.)

General relativity with spin and torsion: Foundations and prospects

International Nuclear Information System (INIS)

Hehl, F.W.; von der Heyde, P.; Kerlick, G.D.; Nester, J.M.

1976-01-01

A generalization of Einstein's gravitational theory is discussed in which the spin of matter as well as its mass plays a dynamical role. The spin of matter couples to a non-Riemannian structure in space-time, Cartan's torsion tensor. The theory which emerges from taking this coupling into account, the U 4 theory of gravitation, predicts, in addition to the usual infinite-range gravitational interaction mediated by the metric field, a new, very weak, spin contact interaction of gravitational origin. We summarize here all the available theoretical evidence that argues for admitting spin and torsion into a relativistic gravitational theory. Not least among this evidence is the demonstration that the U 4 theory arises as a local gauge theory for the Poincare group in space-time. The deviations of the U 4 theory from standard general relativity are estimated, and the prospects for further theoretical development are assessed

The role of nonlinear torsional contributions on the stability of flexural-torsional oscillations of open-cross section beams

Science.gov (United States)

Di Egidio, Angelo; Contento, Alessandro; Vestroni, Fabrizio

2015-12-01

An open-cross section thin-walled beam model, already developed by the authors, has been conveniently simplified while maintaining the capacity of accounting for the significant nonlinear warping effects. For a technical range of geometrical and mechanical characteristics of the beam, the response is characterized by the torsional curvature prevailing over the flexural ones. A Galerkin discretization is performed by using a suitable expansion of displacements based on shape functions. The attention is focused on the dynamic response of the beam to a harmonic force, applied at the free end of the cantilever beam. The excitation is directed along the symmetry axis of the beam section. The stability of the one-component oscillations has been investigated using the analytical model, showing the importance of the internal resonances due to the nonlinear warping coupling terms. Comparison with the results provided by a computational finite element model has been performed. The good agreement among the results of the analytical and the computational models confirms the effectiveness of the simplified model of a nonlinear open-cross section thin-walled beam and overall the important role of the warping and of the torsional elongation in the study of the one-component dynamic oscillations and their stability.

Studies Of Submicron 3He Slabs Using A High Precision Torsional Oscillator

International Nuclear Information System (INIS)

Corcoles, Antonio; Casey, Andrew; Cowan, Brian; Saunders, John; Parpia, Jeevak; Bowley, Roger

2006-01-01

A high precision torsional oscillator has been used to study 3He films of thickness in the range 100 to 350 nm. In previous work we found that the films decoupled from the oscillator motion below 60 mK, in the Knudsen limit. This precluded observation of the superfluid transition. Here we report measurements using a torsional oscillator whose highly polished inner surfaces have been decorated with a low density of silver particles to act as random elastic scattering centres. This modification locks the normal film to the surface. A superfluid transition of the film is observed

Torsional oscillator studies of rotating 3He-A in a slab

International Nuclear Information System (INIS)

Walmsley, P.M.Paul M.; Cousins, D.J.Derek J.; Hall, H.E.Henry E.; Golov, A.I.Andrei I.

2003-01-01

Using a rotating cryostat we have manipulated l-textures of 3 He-A in a 0.26 mm-thick slab contained in a torsional oscillator. Application of a magnetic field or a counterflow due to rotation lead to a sudden distortion of a uniform texture. The uniformity of the initial texture can be characterized by the resulting shift in frequency and bandwidth of the torsional resonance. With a certain density of vortices induced by rotation a uniform texture can be stabilized even in presence of magnetic. The optimal speed of rotation to prepare a uniform texture while cooling through T c was found. The critical velocities for the flow-induced textural transition and vortex nucleation are determined

Isolated adnexal torsion in a 20-week spontaneous twin pregnancy

Directory of Open Access Journals (Sweden)

Ilker Kahramanoglu

2016-01-01

Discussion: Adnexal torsion as a cause of acute abdomen may be kept in mind in pregnants, even if there is no predisposing factor. Laparoscopy may be performed safely in 2nd trimester for acute abdomen.

[Uterine torsion in cattle--therapy and consequences for calf and cow].

Science.gov (United States)

Erteld, E; Krohn, J; Dzhakupov, I T; Wehrend, A

2014-01-01

To summarize the available literature on the therapy of uterine torsion in cattle and the consequences for cow and calf. Analysis of the literature using electronic libraries (PubMed, Medline), German veterinary medical journals and obstetrical textbooks. The therapy includes the attempt to rotate the uterus back into its physiological position. Direct and indirect methods of retorsion are available and applied according to the case conditions. Subsequently, the extraction of the calf can be performed via vaginal delivery or caesarean section. The presence of uterine torsion always leads to dystocia. Following a successful retorsion, the time and degree of uterine torsion strongly influence the progress of the birth. The prognosis also depends on the aforementioned factors and varies between good to unsuccessful. The vitality of the calf displays great variation depending on the literature (14-90%), however, is generally greater under field than clinical conditions. Focussing on the puerperal development of the cow, all grades from mild irritations of the uterine involution to fatal complications occur. The influence on fertility depends on the progress of the birth and existing secondary complications. The risk for electrolyte disturbances is increased (approximately 50%) as is the risk of birth-associated injuries (approximately 20%). The incidence of placental retention varies widely between different authors (3-52%).

Electrostatically actuated torsional resonant sensors and switches

KAUST Repository

Younis, Mohammad I.

2016-12-29

Embodiments in accordance of a torsional resonant sensor disclosure is configured to actuate a beam structure using electrostatic actuation with an AC harmonic load (e.g., AC and DC voltage sources) that is activated upon detecting a particular agent having a mass above a predefined level. In various embodiments, the beam structure may be different types of resonant structures that is at least partially coated or layered with a selective material.

Intermittent torsion of a normal ovary in a child associated with use of a trampoline.

Science.gov (United States)

Yancey, Lynne M

2012-04-01

Ovarian torsion is rare in children. It usually occurs in the presence of ovarian or pelvic pathology. The course of symptoms is typically hours to days. Some authors have speculated that sudden acceleration/deceleration movements may precipitate torsion. The objective of this report is to describe a case of intermittent abdominal pain lasting nearly 6 months, which started when the child began playing regularly on a trampoline, and was ultimately diagnosed as intermittent ovarian torsion of an otherwise normal ovary. A 12-year-old girl presented to the Emergency Department (ED) with 2 h of abdominal pain and vomiting. She reported similar episodes over the previous 6 months. Initial ultrasound, obtained between episodes, was normal. Repeat ultrasound at ED presentation showed no blood flow to the left adnexa. Surgery confirmed the ovary to be twisted 1080 degrees and markedly edematous due to vascular engorgement. The family retrospectively identified the onset of the first episode as happening the same week the child had begun playing regularly on a trampoline. After surgery, she no longer played on the trampoline. At follow-up 22 months later, she had had no recurrence of her symptoms. Intermittent ovarian torsion should be considered as a rare cause of recurrent abdominal pain in children. The presence of blood flow with Doppler ultrasound during acute symptoms does not exclude the diagnosis. Clinicians might also ask about unusual physical activities because several authors have theorized that ovarian torsion could be precipitated by sudden acceleration/deceleration movements. Copyright © 2012. Published by Elsevier Inc.

Surgically Confirmed Intra- and Extratesticular Hematoma Clinically Mimicing Epididymo-Orchitis and Radiologically Mimicing Traumatic Torsion

International Nuclear Information System (INIS)

Akay, Sinan; Kaygisiz, Mustafa; Oztas, Muharrem; Turgut, Mustafa Suphi

2015-01-01

Scrotal blunt trauma may result in injuries, such as testicular rupture, dislocation, torsion, hematoma, spermatic cord injury or contusion, and epididymal, scrotal, and urethral injuries. Ultrasonography (US) has a crucial role in the evaluation of those kinds of pathologies. Early diagnosis of testicular rupture may lead to the salvaging of the testicle by prompt surgical exploration within 72 h. A 21-year-old male with right scrotal swelling and pain complaints was admitted to another hospital one month ago. Epididymo-orchitis was diagnosed and the patient was given medical treatment. The patient was admitted to our emergency service with ongoing complaints. The patient stated that the pain and swelling suddenly developed after prolonged marching. On US, a large hematoma was detected between the leaves of the tunica vaginalis, and rupture from the lower pole was diagnosed. On color Doppler US, no vascularity was observed in the heterogeneous testicular parenchyma. Traumatic torsion was primarily suggested. Intraoperatively, an extratesticular hematoma, hematocele, and rupture were confirmed but torsion was not found. Because the hematoma entirely replaced the normal parenchyma, orchiectomy was performed. Testicular rupture may occur even after moderate sportive action such as prolonged marching. If any delay occurs in diagnosis and/or operation, the coagulum may replace the entire parenchyma. We think that US and clinical findings may sometimes mislead the physicians and cause misdiagnoses, such as inflammation or torsion. In this paper, we present a complex delayed diagnosed example case of testicular rupture clinically mimicing epididymo-orchitis and radiologically mimicing traumatic testicular torsion

Generalised teleparallel quintom dark energy non-minimally coupled with the scalar torsion and a boundary term

Science.gov (United States)

Bahamonde, Sebastian; Marciu, Mihai; Rudra, Prabir

2018-04-01

Within this work, we propose a new generalised quintom dark energy model in the teleparallel alternative of general relativity theory, by considering a non-minimal coupling between the scalar fields of a quintom model with the scalar torsion component T and the boundary term B. In the teleparallel alternative of general relativity theory, the boundary term represents the divergence of the torsion vector, B=2∇μTμ, and is related to the Ricci scalar R and the torsion scalar T, by the fundamental relation: R=‑T+B. We have investigated the dynamical properties of the present quintom scenario in the teleparallel alternative of general relativity theory by performing a dynamical system analysis in the case of decomposable exponential potentials. The study analysed the structure of the phase space, revealing the fundamental dynamical effects of the scalar torsion and boundary couplings in the case of a more general quintom scenario. Additionally, a numerical approach to the model is presented to analyse the cosmological evolution of the system.

Torsional splittings in the diode laser slit-jet spectra of the ν6 fundamental of 1-chloro-1,1-difluoroethane (HCFC-142b)

Science.gov (United States)

di Lauro, Carlo; D'Amico, Giuseppe; Snels, Marcel

2009-04-01

High resolution infrared spectra (0.001 cm -1 FWHM) have been measured for mixtures of 1-chloro-1,1-difluoroethane in Ne, expanded in a supersonic planar jet. The ν6 fundamental, infrared active with a dominant parallel transition moment, exhibits a remarkable splitting of about 0.035 cm -1 for both 35Cl and 37Cl isotopomers. Several mechanisms of interaction of ν6 with states with high torsional excitation are critically examined to explain the observed effect. It is concluded that the observed torsional splitting patterns can be explained in terms of a torsional Coriolis interaction between ν6 and a highly excited torsional mode, 6 ν18. A full numerical analysis, performed including a torsional Coriolis term in the Hamiltonian, shows that the interaction mechanism requires a torsional barrier height of about 1270 cm -1.

Omental torsion in a captive polar bear (Ursus maritimus).

Science.gov (United States)

Mendez-Angulo, Jose L; Funes, Francisco J; Trent, Ava M; Willette, Michelle; Woodhouse, Kerry; Renier, Anna C

2014-03-01

This is the first case report of an omental torsion in a polar bear (Ursus maritimus). A captive, 23-yr-old, 250-kg, intact female polar bear presented to the University of Minnesota Veterinary Medical Center with a 2-day history of lethargy, depression, and vomiting. Abdominal ultrasound identified large amounts of hyperechoic free peritoneal fluid. Ultrasound-guided abdominocentesis was performed and yielded thick serosanguinous fluid compatible with a hemoabdomen. An exploratory laparotomy revealed a large amount of malodorous, serosanguineous fluid and multiple necrotic blood clots associated with a torsion of the greater omentum and rupture of a branch of the omental artery. A partial omentectomy was performed to remove the necrotic tissue and the abdomen was copiously lavaged. The polar bear recovered successfully and is reported to be clinically well 6 mo later. This condition should be considered as a differential in bears with clinical signs of intestinal obstruction and hemoabdomen.

Activation of a yeast replication origin near a double-stranded DNA break.

Science.gov (United States)

Raghuraman, M K; Brewer, B J; Fangman, W L

1994-03-01

Irradiation in the G1 phase of the cell cycle delays the onset of DNA synthesis and transiently inhibits the activation of replication origins in mammalian cells. It has been suggested that this inhibition is the result of the loss of torsional tension in the DNA after it has been damaged. Because irradiation causes DNA damage at an undefined number of nonspecific sites in the genome, it is not known how cells respond to limited DNA damage, and how replication origins in the immediate vicinity of a damage site would behave. Using the sequence-specific HO endonuclease, we have created a defined double-stranded DNA break in a centromeric plasmid in G1-arrested cells of the yeast Saccharomyces cerevisiae. We show that replication does initiate at the origin on the cut plasmid, and that the plasmid replicates early in the S phase after linearization in vivo. These observations suggest that relaxation of a supercoiled DNA domain in yeast need not inactivate replication origins within that domain. Furthermore, these observations rule out the possibility that the late replication context associated with chromosomal termini is a consequence of DNA ends.

Acupoint Massage in Relieving Pain after Ureteroscopic Holmium Laser Lithotripsy

Institute of Scientific and Technical Information of China (English)

Xia Wei-qin

2014-01-01

Objective: To observe the effect of acupoint massage in relieving pain after ureteroscopic holmium laser lithotripsy. Methods: Ninety-two patients undergone ureteroscopic holmium laser lithotripsy were enrolled and randomized into a treatment group and a control group, 46 in each group. Patients in the control group were given regular nursing care, while patients in the treatment group were intervened by acupoint massage in addition to the regular nursing care. The pain was evaluated by visual analogue scale (VAS) at 6 h, 12 h, and 24 h after operation, and compared between the two groups. Results:There was no significant difference in comparing the VAS score at 6 h after operation between the two groups (P>0.05). The VAS scores in the treatment group at 12 h and 24 h after operation were significantly lower than those in the control group (both P Conclusion: Acupoint massage can effectively relieve the pain after ureteroscopic holmium laser lithotripsy, reduce the use of analgesics, and promote the recovery.

Torsion axial vector and Yvon-Takabayashi angle: zitterbewegung, chirality and all that

Science.gov (United States)

Fabbri, Luca; da Rocha, Roldão

2018-03-01

We consider propagating torsion as a completion of gravitation in order to describe the dynamics of curved-twisted space-times filled with Dirac spinorial fields; we discuss interesting relationships of the torsion axial vector and the curvature tensor with the Yvon-Takabayashi angle and the module of the spinor field, that is the two degrees of freedom of the spinor field itself: in particular, we shall discuss in what way the torsion axial vector could be seen as the potential of a specific interaction of the Yvon-Takabayashi angle, and therefore as a force between the two chiral projections of the spinor field itself. Chiral interactions of the components of a spinor may render effects of zitterbewegung, as well as effective mass terms and other related features: we shall briefly sketch some of the analogies and differences with the similar but not identical situation given by the Yukawa interaction occurring in the Higgs sector of the standard model. We will provide some overall considerations about general consequences for contemporary physics, consequences that have never been discussed before, so far as we are aware, in the present physics literature.

Torsional resistance of XP-endo Shaper at body temperature compared with several nickel-titanium rotary instruments.

Science.gov (United States)

Elnaghy, A M; Elsaka, S E

2018-05-01

To compare the torsional resistance of XP-endo Shaper (XPS; size 30, .01 taper, FKG Dentaire, La Chaux-de-Fonds, Switzerland) instruments at body temperature with TRUShape (TRS; size 30, .06 taper, Dentsply Tulsa Dental Specialties, Tulsa, OK, USA), ProFile Vortex (PV; size 30, .04 taper, Dentsply Tulsa Dental Specialties) and FlexMaster (FM; size 30, .04 taper, VDW GmbH, Munich, Germany) nickel-titanium rotary instruments. A metal block with a square-shaped mould (5 mm × 5 mm × 5 mm) was positioned inside a glass container. Five millimetres of the tip of each instrument was held inside the metal block by filling the mould with a resin composite. The instruments were tested for torsional resistance in saline solution at 37 °C. Data were analysed using one-way analysis of variance (anova) and Tukey post hoc tests. The significance level was set at P instruments tested (P instruments (P = 0.211). The ranking for torsional resistance values was: FM > PV > TRS > XPS. FlexMaster and ProFile Vortex instruments were more resistant to torsional stress compared with TRUShape and XP-endo Shaper instruments. The manufacturing process used to produce XP-endo Shaper instruments did not enhance their resistance to torsional stress as compared with the other instruments. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Burden and seasonality of testicular torsion in tropical Africa ...

African Journals Online (AJOL)

Jibril O. Bello

2018-02-14

Feb 14, 2018 ... Department of Surgery, University of Ilorin Teaching Hospital, Ilorin, Nigeria ... Cases occurred 91% higher than average during the cold season (November to .... tion strategies through the education of school staff and students on .... torsion and weather conditions: analysis of 21,289 cases in Brazil. Int.

Modeling the Elastic and Damping Properties of the Multilayered Torsion Bar-Blade Structure of Rotors of Light Helicopters of the New Generation. 1. Finite-Element Approximation of the Torsion Bar

Science.gov (United States)

Paimushin, V. N.; Shishkin, V. M.

2015-11-01

A prismatic semiquadratic element with a nonclassical approximation of its displacements is suggested for modeling the composite and soft layers of a torsion bar and multilayered plate-rod structures. The stiffness, weight, damping, and geometric stiffness matrices of the above-mentioned element are obtained. Expressions for computing stresses in the finite element under the action of static loads and vibrations in the resonance zone are presented. Test examples confirming the validity of the element suggested are given. An example of finite element determination of the dynamic response of a multilayered torsion bar in the resonant mode is considered.

Structural Transitions in Supercoiled Stretched DNA

Science.gov (United States)

v, Croquette

1998-03-01

Using magnetic micromanipulation techniques [Strick 96]( uc(T.R.) Strick, J.-F. Allemand, D. Bensimon, A. Bensimon) and uc(V.) Croquette, "The elasticity of a single supercoiled DNA molecule", Science, 271, 1835 (1996)., we have studied the mechanical properties (force versus extension) of single DNA molecules under a wide range of torsional stresses (supercoiling). We show that unwinding the DNA double helix leads to a phase separation between regular B-DNA and denaturation bubbles. The fraction of denatured molecule increases linearly with the degree of unwinding, beginning at a value of 1% unwinding. We have confirmed this denatured state by hybridization of homologous single-stranded DNA probes and by a chemical attack of the exposed bases. Surprisingly, when we overwind the molecule, the elasticity curves we obtain may also be interpreted by the coexistence of two phases, B-DNA and a new phase which we note P-DNA. The fraction of this new phase increases smoothly with overwinding, beginning at 3 % and continuing up to 300 %. Our results indicate that this new phase is four times more twisted that the standard B-DNA and is 1.75 times longer. Although the structure of this phase is not yet known, such a high twisting can only be attained if the sugar-phosphate backbones of the two strands are twisted closely while the bases are expelled outside of the molecule's core, in a structure reminiscent of the one proposed by Pauling. Indeed we have shown that this new phase is sensitive to chemical attack whereas the B-DNA is not. This new phase begins to appear on a molecule overwound by 3 % and stretched by a force of 5 pN, conditions typically encountered in vivo during gene transcription. This new phase may thus play a biological role (for more details).

The Einstein static universe with torsion and the sign problem of the cosmological constant

International Nuclear Information System (INIS)

Boehmer, C G

2004-01-01

In the field equations of Einstein-Cartan theory with cosmological constant a static spherically symmetric perfect fluid with spin density satisfying the Weyssenhoff restriction is considered. This serves as a rough model of space filled with (fermionic) dark matter. From this the Einstein static universe with constant torsion is constructed, generalizing the Einstein cosmos to Einstein-Cartan theory. The interplay between torsion and the cosmological constant is discussed. A possible way out of the cosmological constant's sign problem is suggested

Berry phase for spin-1/2 particles moving in a space-time with torsion

International Nuclear Information System (INIS)

Alimohammadi, M.; Shariati, A.

2001-01-01

Berry phase for a spin-1/2 particle moving in a flat space-time with torsion is investigated in the context of the Einstein-Cartan-Dirac model. It is shown that if the torsion is due to a dense polarized background, then there is a Berry phase only if the fermion is massless and its momentum is perpendicular to the direction of the background polarization. The order of magnitude of this Berry phase is discussed in other theoretical frameworks. (orig.)

Berry phase for spin-1/2 particles moving in a space-time with torsion

Energy Technology Data Exchange (ETDEWEB)

Alimohammadi, M. [Dept. of Physics, Tehran Univ. (Iran); Shariati, A. [Inst. for Advanced Studies in Basic Sciences, Zanjan (Iran); Inst. for Studies in Theoretical Physics and Mathematics, Tehran (Iran)

2001-06-01

Berry phase for a spin-1/2 particle moving in a flat space-time with torsion is investigated in the context of the Einstein-Cartan-Dirac model. It is shown that if the torsion is due to a dense polarized background, then there is a Berry phase only if the fermion is massless and its momentum is perpendicular to the direction of the background polarization. The order of magnitude of this Berry phase is discussed in other theoretical frameworks. (orig.)

Effect of web openings on the structural behavior of RC beams subjected to pure torsion

Directory of Open Access Journals (Sweden)

Abdo Taha

2017-01-01

Full Text Available In the construction of modern buildings, the presence of openings became a necessity nowadays in order to accommodate the many pipes and ducts required for the different services. On the other hand, the presence of these openings in RC beams affects their structural behavior. One important behavior that needs further study would be torsion. Currently, there are no guide lines available to analyze or design RC beams with web openings under pure torsion. Thus, the main objective of this research is to investigate the behavior of simply supported RC beams with openings subjected to pure torsion. In the first part of this paper, an experimental study is conducted on seven beams subjected to pure torsion loading in order to investigate the effect of the number of openings, the spacing between stirrups, and beam depth. All beams have a constant clear span length of 1800 mm and a constant beam width of 150 mm. The beams have varying opening number and stirrups arrangement as well as varying beam depth in order to investigate the effect of these parameters on the behavior of the beams. Systematic measurements such as the cracking torque, the ultimate torque, the angle of rotation of the beam at cracking, and the angle of rotation of the beam at the ultimate load are conducted for further understanding of the beam behavior under torsion. In the second part of the paper, the experimental results are compared with the numerical results obtained using the non-linear finite element analysis program, ANSYS. Good agreement between the experimental and numerical results is found.

Acute effects of massage or active exercise in relieving muscle soreness

DEFF Research Database (Denmark)

Andersen, Lars L; Jay, Kenneth; Andersen, Christoffer H

2013-01-01

Massage is commonly believed to be the best modality for relieving muscle soreness. However, actively warming up the muscles with exercise may be an effective alternative. The purpose of this study was to compare the acute effect of massage with active exercise for relieving muscle soreness. Twenty...... healthy female volunteers (mean age 32 years) participated in this examiner-blind randomized controlled trial (ClinicalTrials.gov NCT01478451). The participants performed eccentric contractions for the upper trapezius muscle on a Biodex dynamometer. Delayed onset muscle soreness (DOMS) presented 48 hours...... later, at which the participants (a) received 10 minutes of massage of the trapezius muscle or (b) performed 10 minutes of active exercise (shoulder shrugs 10 × 10 reps) with increasing elastic resistance (Thera-Band). First, 1 treatment was randomly applied to 1 shoulder while the contralateral...

Electronic torsional sound in linear atomic chains: Chemical energy transport at 1000 km/s

Energy Technology Data Exchange (ETDEWEB)

Kurnosov, Arkady A.; Rubtsov, Igor V.; Maksymov, Andrii O.; Burin, Alexander L., E-mail: aburin@tulane.edu [Department of Chemistry, Tulane University, New Orleans, Louisiana 70118 (United States)

2016-07-21

We investigate entirely electronic torsional vibrational modes in linear cumulene chains. The carbon nuclei of a cumulene are positioned along the primary axis so that they can participate only in the transverse and longitudinal motions. However, the interatomic electronic clouds behave as a torsion spring with remarkable torsional stiffness. The collective dynamics of these clouds can be described in terms of electronic vibrational quanta, which we name torsitons. It is shown that the group velocity of the wavepacket of torsitons is much higher than the typical speed of sound, because of the small mass of participating electrons compared to the atomic mass. For the same reason, the maximum energy of the torsitons in cumulenes is as high as a few electronvolts, while the minimum possible energy is evaluated as a few hundred wavenumbers and this minimum is associated with asymmetry of zero point atomic vibrations. Theory predictions are consistent with the time-dependent density functional theory calculations. Molecular systems for experimental evaluation of the predictions are proposed.

Electronic torsional sound in linear atomic chains: Chemical energy transport at 1000 km/s

Science.gov (United States)

Kurnosov, Arkady A.; Rubtsov, Igor V.; Maksymov, Andrii O.; Burin, Alexander L.

2016-07-01

We investigate entirely electronic torsional vibrational modes in linear cumulene chains. The carbon nuclei of a cumulene are positioned along the primary axis so that they can participate only in the transverse and longitudinal motions. However, the interatomic electronic clouds behave as a torsion spring with remarkable torsional stiffness. The collective dynamics of these clouds can be described in terms of electronic vibrational quanta, which we name torsitons. It is shown that the group velocity of the wavepacket of torsitons is much higher than the typical speed of sound, because of the small mass of participating electrons compared to the atomic mass. For the same reason, the maximum energy of the torsitons in cumulenes is as high as a few electronvolts, while the minimum possible energy is evaluated as a few hundred wavenumbers and this minimum is associated with asymmetry of zero point atomic vibrations. Theory predictions are consistent with the time-dependent density functional theory calculations. Molecular systems for experimental evaluation of the predictions are proposed.

Do physical examination and CT-scan measures of femoral neck anteversion and tibial torsion relate to each other?

Science.gov (United States)

Sangeux, Morgan; Mahy, Jessica; Graham, H Kerr

2014-01-01

Informed clinical decision making for femoral and/or tibial de-rotation osteotomies requires accurate measurement of patient function through gait analysis and anatomy through physical examination of bony torsions. Validity of gait analysis has been extensively studied; however, controversy remains regarding the accuracy of physical examination measurements of femoral and tibial torsion. Comparison between CT-scans and physical examination measurements of femoral neck anteversion (FNA) and external tibial torsion (ETT) were retrospectively obtained for 98 (FNA) and 64 (ETT) patients who attended a tertiary hospital for instrumented gait analysis between 2007 and 2010. The physical examination methods studied for femoral neck anteversion were the trochanteric prominence angle test (TPAT) and the maximum hip rotation arc midpoint (Arc midpoint) and for external tibial torsion the transmalleolar axis (TMA). Results showed that all physical examination measurements statistically differed to the CT-scans (bias(standard deviation): -2(14) for TPAT, -10(12) for Arc midpoint and -16(9) for TMA). Bland and Altman plots showed that method disagreements increased with increasing bony torsions in all cases but notably for TPAT. Regression analysis showed that only TMA and CT-scan measurement of external tibial torsion demonstrated good (R(2)=57%) correlation. Correlations for both TPAT (R(2)=14%) and Arc midpoint (R(2)=39%) with CT-scan measurements of FNA were limited. We conclude that physical examination should be considered as screening techniques rather than definitive measurement methods for FNA and ETT. Further research is required to develop more accurate measurement methods to accompany instrumented gait analysis. Copyright © 2013. Published by Elsevier B.V.

Protein backbone and sidechain torsion angles predicted from NMR chemical shifts using artificial neural networks

Energy Technology Data Exchange (ETDEWEB)

Shen Yang; Bax, Ad, E-mail: bax@nih.gov [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)

2013-07-15

A new program, TALOS-N, is introduced for predicting protein backbone torsion angles from NMR chemical shifts. The program relies far more extensively on the use of trained artificial neural networks than its predecessor, TALOS+. Validation on an independent set of proteins indicates that backbone torsion angles can be predicted for a larger, {>=}90 % fraction of the residues, with an error rate smaller than ca 3.5 %, using an acceptance criterion that is nearly two-fold tighter than that used previously, and a root mean square difference between predicted and crystallographically observed ({phi}, {psi}) torsion angles of ca 12 Masculine-Ordinal-Indicator . TALOS-N also reports sidechain {chi}{sup 1} rotameric states for about 50 % of the residues, and a consistency with reference structures of 89 %. The program includes a neural network trained to identify secondary structure from residue sequence and chemical shifts.

SENP7 Potentiates cGAS Activation by Relieving SUMO-Mediated Inhibition of Cytosolic DNA Sensing.

Directory of Open Access Journals (Sweden)

Ye Cui

2017-01-01

Full Text Available Cyclic GMP-AMP (cGAMP synthase (cGAS, a.k.a. MB21D1, a cytosolic DNA sensor, catalyzes formation of the second messenger 2'3'-cGAMP that activates the stimulator of interferon genes (STING signaling. How the cGAS activity is modulated remains largely unknown. Here, we demonstrate that sentrin/SUMO-specific protease 7 (SENP7 interacted with and potentiated cGAS activation. The small ubiquitin-like modifier (SUMO was conjugated onto the lysine residues 335, 372 and 382 of cGAS, which suppressed its DNA-binding, oligomerization and nucleotidyl-transferase activities. SENP7 reversed this inhibition via catalyzing the cGAS de-SUMOylation. Consistently, silencing of SENP7 markedly impaired the IRF3-responsive gene expression induced by cGAS-STING axis. SENP7-knockdown mice were more susceptible to herpes simplex virus 1 (HSV-1 infection. SENP7 was significantly up-regulated in patients with SLE. Our study highlights the temporal modulation of the cGAS activity via dynamic SUMOylation, uncovering a novel mechanism for fine-tuning the STING signaling in innate immunity.

Regenerative braking systems with torsional springs made of carbon nanotube yarn

International Nuclear Information System (INIS)

Liu, S; Martin, C; Livermore, C; Lashmore, D; Schauer, M

2014-01-01

The demonstration of large stroke, high energy density and high power density torsional springs based on carbon nanotube (CNT) yarns is reported, as well as their application as an energy-storing actuator for regenerative braking systems. Originally untwisted CNT yarn is cyclically loaded and unloaded in torsion, with the maximum rotation angle increasing until failure. The maximum extractable energy density is measured to be as high as 6.13 kJ/kg. The tests also reveal structural reorganization and hysteresis in the torsional loading curves. A regenerative braking system is built to capture the kinetic energy of a wheel and store it as elastic energy in twisted CNT yarns. When the yam's twist is released, the stored energy reaccelerates the wheel. The measured energy and mean power densities of the CNT yarns in the simple regenerative braking system are up to 4.69 kJ/kg and 1.21 kW/kg, respectively. A slightly lower energy density of up to 1.23 kJ/kg and a 0.29 kW/kg mean power density are measured for the CNT yarns in a more complex system that mimics a unidirectional rotating regenerative braking mechanism. The lower energy densities for CNT yarns in the regenerative braking systems as compared with the yarns themselves reflect the frictional losses of the regenerative systems

Microstructure and texture development during high-strain torsion of NiAl

Energy Technology Data Exchange (ETDEWEB)

Kloeden, B.

2006-07-01

In this study polycrystalline NiAl has been subjected to torsion deformation. The deformation, microstructure and texture development subject to the shear strain are studied by different techniques (Electron Back-Scatter and High Energy Synchrotron Radiation). Beside the development of microstructure and texture with shear strain, the effect of an initial texture as well as the deformation temperature on the development of texture and microstructure constitute an important part of this study. Therefore, samples with three different initial textures were deformed in the temperature range T=700 K-1300 K. The shear stress-shear strain curves are characterized by a peak at low strains, which is followed by softening and a steady state at high strains. Grain refinement takes place for all samples and the average grain size decreases with temperature. For temperatures T>1000 K, discontinuous dynamic recrystallization occurs, by which new grains form by nucleation and subsequent growth. The texture is characterized by two components, {l_brace}100{r_brace}<100> (cube,C) and {l_brace}110{r_brace}<100> (Goss,G). Torsional creep of NiAl is characterized by a stress exponent, which depends on temperature and an activation energy, which is stress dependent. The Swift effect, due to which samples change their axial dimension during torsion without applied axial stress, is observed for NiAl. (orig.)

Regenerative braking systems with torsional springs made of carbon nanotube yarn

Science.gov (United States)

Liu, S.; Martin, C.; Lashmore, D.; Schauer, M.; Livermore, C.

2014-11-01

The demonstration of large stroke, high energy density and high power density torsional springs based on carbon nanotube (CNT) yarns is reported, as well as their application as an energy-storing actuator for regenerative braking systems. Originally untwisted CNT yarn is cyclically loaded and unloaded in torsion, with the maximum rotation angle increasing until failure. The maximum extractable energy density is measured to be as high as 6.13 kJ/kg. The tests also reveal structural reorganization and hysteresis in the torsional loading curves. A regenerative braking system is built to capture the kinetic energy of a wheel and store it as elastic energy in twisted CNT yarns. When the yam's twist is released, the stored energy reaccelerates the wheel. The measured energy and mean power densities of the CNT yarns in the simple regenerative braking system are up to 4.69 kJ/kg and 1.21 kW/kg, respectively. A slightly lower energy density of up to 1.23 kJ/kg and a 0.29 kW/kg mean power density are measured for the CNT yarns in a more complex system that mimics a unidirectional rotating regenerative braking mechanism. The lower energy densities for CNT yarns in the regenerative braking systems as compared with the yarns themselves reflect the frictional losses of the regenerative systems.

Einstein-Cartan Gravity with Torsion Field Serving as an Origin for the Cosmological Constant or Dark Energy Density

Science.gov (United States)

Ivanov, A. N.; Wellenzohn, M.

2016-09-01

We analyse the Einstein-Cartan gravity in its standard form { R }=R+{{ K }}2, where { R } {and} R are the Ricci scalar curvatures in the Einstein-Cartan and Einstein gravity, respectively, and {{ K }}2 is the quadratic contribution of torsion in terms of the contorsion tensor { K }. We treat torsion as an external (or background) field and show that its contribution to the Einstein equations can be interpreted in terms of the torsion energy-momentum tensor, local conservation of which in a curved spacetime with an arbitrary metric or an arbitrary gravitational field demands a proportionality of the torsion energy-momentum tensor to a metric tensor, a covariant derivative of which vanishes owing to the metricity condition. This allows us to claim that torsion can serve as an origin for the vacuum energy density, given by the cosmological constant or dark energy density in the universe. This is a model-independent result that may explain the small value of the cosmological constant, which is a long-standing problem in cosmology. We show that the obtained result is valid also in the Poincaré gauge gravitational theory of Kibble, where the Einstein-Hilbert action can be represented in the same form: { R }=R+{{ K }}2.

Remote pipeline assessment and condition monitoring using low-frequency axisymmetric waves: a theoretical study of torsional wave motion

Science.gov (United States)

Muggleton, J. M.; Rustighi, E.; Gao, Y.

2016-09-01

Waves that propagate at low frequencies in buried pipes are of considerable interest in a variety of practical scenarios, for example leak detection, remote pipe detection, and pipeline condition assessment and monitoring. Particularly useful are the n = 0, or axisymmetric, modes in which there is no displacement (or pressure) variation over the pipe cross section. Previous work has focused on two of the three axisymmetric wavetypes that can propagate: the s = 1, fluid- dominated wave; and the s = 2, shell-dominated wave. In this paper, the third axisymmetric wavetype, the s = 0 torsional wave, is studied. Whilst there is a large body of research devoted to the study of torsional waves and their use for defect detection in pipes at ultrasonic frequencies, little is known about their behaviour and possible exploitation at lower frequencies. Here, a low- frequency analytical dispersion relationship is derived for the torsional wavenumber for a buried pipe from which both the wavespeed and wave attenuation can be obtained. How the torsional waves subsequently radiate to the ground surface is then investigated, with analytical expressions being presented for the ground surface displacement above the pipe resulting from torsional wave motion within the pipe wall. Example results are presented and, finally, how such waves might be exploited in practice is discussed.

Secondary flow structures in a 180∘ elastic curved vessel with torsion under steady and pulsatile inflow conditions

Science.gov (United States)

Najjari, Mohammad Reza; Plesniak, Michael W.

2017-11-01

Secondary flow vortical structures were investigated in an elastic 180° curved pipe with and without torsion under steady and pulsatile flow using particle image velocimetry (PIV). The elastic thin-walled curved pipes were constructed using Sylgard 184, and inserted into a bath of refractive index matched fluid to perform PIV. A vortex identification method was employed to identify various vortical structures in the flow. The secondary flow structures in the planar compliant model with dilatation of 0.61%-3.23% under pulsatile flow rate were compared with the rigid vessel model results, and it was found that local vessel compliance has a negligible effect on secondary flow morphology. The secondary flow structures were found to be more sensitive to out of plane curvature (torsion) than to vessel compliance. Torsion distorts the symmetry of secondary flow and results in more complex vortical structures in both steady and pulsatile flows. In high Re number steady flow with torsion, a single dominant vortical structure can be detected at the middle of the 90° cross section. In pulsatile flow with torsion, the split-Dean and Lyne-type vortices with same rotation direction originating from opposite sides of the cross section tend to merge together. supported by GW Center for Biomimetics and Bioinspired Engineering.

Ovarian torsion: Case–control study comparing the sensitivity and specificity of ultrasonography and computed tomography for diagnosis in the emergency department

International Nuclear Information System (INIS)

Swenson, David W.; Lourenco, Ana P.; Beaudoin, Francesca L.; Grand, David J.; Killelea, Alison G.; McGregor, Alyson J.

2014-01-01

Objective: Evaluate the sensitivity and specificity of pelvic ultrasound (US) and abdominopelvic computed tomography (CT) for the identification of ovarian torsion in women presenting to the emergency department with acute lower abdominal or pelvic pain. Materials and methods: This is a retrospective study of 20 cases of ovarian torsion and 20 control patients, all of whom had both US and CT performed in the emergency department. Two radiologists who were blinded to clinical data interpreted all studies as (1) demonstrating an abnormal ovary or not, and (2) suggestive of torsion or not. Sensitivity, specificity and interobserver variation were calculated for each imaging modality. Results: Pelvic US was interpreted as demonstrating an abnormal ovary in 90.0% of ovarian torsion cases by reader 1, and in 100.0% by reader 2, whereas CT was interpreted as revealing an abnormal ovary in 100.0% of torsion cases by both readers. Pelvic US for ovarian torsion was 80.0% sensitive (95% CI, 58.4–91.9%) and 95.0% specific (95% CI, 76.4–99.1%) for reader 1, while 80.0% sensitive (95% CI, 58.4–91.9%) and 85.0% specific (95% CI, 64.0–95.0%) for reader 2. Interobserver agreement for pelvic US was fair (Kappa = 0.60). Abdominopelvic CT for ovarian torsion was 100.0% sensitive (95% CI, 83.9–100.0%) and 85.0% specific (95% CI, 64.0–94.5%) for reader 1, while 90.0% sensitive (95% CI, 69.9–97.2%) and 90.0% specific (95% CI, 69.9–97.2%) for reader 2. Interobserver agreement was excellent (Kappa = 0.85). Conclusion: The diagnostic performance of CT is not shown to be significantly different from that of US in identifying ovarian torsion in this study. These results suggest that when CT demonstrates findings of ovarian torsion, the performance of another imaging exam (i.e. US) that delays therapy is unlikely to improve preoperative diagnostic yield

[Peripubertal ovarian cyst torsion as an early complication of undiagnosed polycystic ovarian syndrome].

Science.gov (United States)

Ságodi, László; Schmidt, Ildikó; Vámosi, Ildikó; Barkai, László

2013-01-20

The aim of the authors is to present two cases which raise the possibility of an association between polycystic ovarian syndrome/hyperandrogenism and ovarian cyst torsion in peripubertal girls. Androgen excess may cause more frequently ovarian cyst formation in premenarcheal or young adolescents with undiagnosed polycystic ovarian syndrome than in adults. The authors recommend that polycystic ovarian syndrome as well as late onset congenital adrenal hyperplasia should be considered in peripubertal adolescents with ovarian cyst torsion. In case polycystic ovarian syndrome is confirmed, adequate management according to age and pubertal development of the patients should be commenced.

State and Substate Estimates of Nonmedical Use of Prescription Pain Relievers

Science.gov (United States)

... with other local area data to enhance statistical power and analytic capability. 10 Delete Template National, Regional, and State Estimates In this section, estimates of past year nonmedical use of prescription pain relievers among people aged 12 or older are ...

Acute abdomen in early pregnancy caused by torsion of bilateral huge multiloculated ovarian cysts

OpenAIRE

Sathiyakala Rajendran; Suthanthira Devi

2015-01-01

The association of pregnancy and torsion of bilateral huge benign ovarian cyst is rare. We report a case of multigravida at 13 weeks of pregnancy presenting with acute onset of lower abdominal pain. Ultrasound revealed bilateral multiloculated ovarian cysts of size 10x10 cm on right side and 15x10cm on left side with evidence of torsion and a single live intrauterine fetus of gestational age 13 weeks 4 days. Emergency laparotomy was done with vaginal susten 200 mg as perioperative tocolysis. ...

Portal Venous Thrombosis Developing after Torsion of a Wandering ...

African Journals Online (AJOL)

2017-03-06

Mar 6, 2017 ... Department of General Surgery, YüzüncüYıl University. Faculty of ... an emergency surgery. The spleen was ... exist in acute, subacute or chronic forms, depending on the development ... of spleen infarction, sepsis and acute pancreatitis. ... In cases of torsion of wandering spleen, the treatment principally ...

Note: Determination of torsional spring constant of atomic force microscopy cantilevers: Combining normal spring constant and classical beam theory

DEFF Research Database (Denmark)

Álvarez-Asencio, R.; Thormann, Esben; Rutland, M.W.

2013-01-01

A technique has been developed for the calculation of torsional spring constants for AFM cantilevers based on the combination of the normal spring constant and plate/beam theory. It is easy to apply and allow the determination of torsional constants for stiff cantilevers where the thermal power s...... spectrum is difficult to obtain due to the high resonance frequency and low signal/noise ratio. The applicability is shown to be general and this simple approach can thus be used to obtain torsional constants for any beam shaped cantilever. © 2013 AIP Publishing LLC....

Low frequency torsional vibration gaps in the shaft with locally resonant structures

International Nuclear Information System (INIS)

Yu Dianlong; Liu Yaozong; Wang Gang; Cai Li; Qiu Jing

2006-01-01

The propagation of torsional wave in the shaft with periodically attached local resonators is studied with the transfer matrix theory and the finite element method. The analytical dispersion relation and the complex band structure of such a structure is presented for the first time, which indicates the existence of low frequency gaps. The effect of shaft material on the vibration attenuation in band gap is investigated. The frequency response function of the shaft with finite periodic locally resonant oscillators is simulated with finite element method, which shows large vibration attenuation in the frequency range of the gap as expected. The low frequency torsional gap in shafts provides a new idea for vibration control

Torsion and curvature in higher dimensional supergravity theories

International Nuclear Information System (INIS)

Smith, A.W.; Pontificia Univ. Catolica do Rio de Janeiro

1983-01-01

This work is an extension of Dragon's theorems to higher dimensional space-time. It is shown that the first set of Bianchi identities allow us to express the curvature components in terms of torsion components and its covariant derivatives. It is also shown that the second set of Bianchi identities does not give any new information which is not already contained in the first one. (Author) [pt

New measurements of G using the measurement standards laboratory torsion balance

International Nuclear Information System (INIS)

Armstrong, T.R.; Fitzgerald, M.P.

2003-01-01

This Letter presents the results of a series of measurements of the Newtonian gravitational constant G using the compensated torsion balance developed at the Measurement Standards Laboratory. Since our last published result using the torsion balance in the compensated mode of operation [Meas. Sci. Technol. 10, 439 (1999)], several improvements have been made to reduce the uncertainty in the final result. The new measurements have used both stainless steel and copper large masses. The values of G for the two sets of masses are in good agreement. After combining all of the measurements we get a value of G=6.673 87(0.000 27)x10 -11 m 3 kg -1 s -2 . This new value is 5 parts in 10 5 smaller than our previous published values

Double-stranded DNA translocase activity of transcription factor TFIIH and the mechanism of RNA polymerase II open complex formation.

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