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At least 991 records · Page 55Linked to original sources
PubMed2002

The biomechanical effects of the inclusion of a torque absorber on trans-femoral amputee gait, a pilot study.

This paper reports on a pilot study investigating the effects on the gait of two transfemoral amputees of to the inclusion of a torque absorber (TA) and its location relative to the knee unit. Both subjects carried out gait tests with a prosthesis with no TA with, a TA proximal to the knee unit and with a TA distal to the knee unit. Three-dimensional gait analysis was carried out to establish the kinematic and kinetic gait parameters of both the prosthetic and sound side. It was found that the TA did not significantly affect the sagittal kinetic and kinematic parameters of the sound or the prosthetic side. However, for one subject the axial rotation of the socket relative to the foot was significantly greater with the TA. It was concluded that by using the methodology of this pilot study, it is possible to investigate the rotations in the transverse plane within the prosthetic limb and pelvis. Further, including a TA may reduce the relative motion between the stump and the socket and therefore may decrease skin breakdown due to diminished shear forces.

Amputation, Surgical↗
PubMed1999

A study on the rotational torque movement of mandible in patients with TMJ closed lock.

The mandibular rotational angle and distance were measured during various movements of temporomandibular joint (TMJ) closed lock patients (17 women, 23.9 +/- 6.6 years). The measurements were compared with those of the healthy controls (18 women, 24.0 +/- 1.4 years) using the BioPAK system (BioResearch Inc. Milwaukee, USA), which can analyze mandibular rotational torque movements. During maximum mouth opening movement, the parameters of the patient group were significantly larger than those of the control group in horizontal plane (p < 0.05) but vice versa in frontal plane (p < 0.001). During protrusive movement, the parameters of patients were significantly larger than those of control group in frontal and horizontal plane (p < 0.01, p < 0.05). During lateral excursive movement to the affected side of patients, the parameters were significantly larger than those to the unaffected side in frontal plane (p < 0.05).

Adult↗
PubMed2004

Correlation between Torque tenovirus infection and serum levels of eosinophil cationic protein in children hospitalized for acute respiratory diseases.

Children with bronchopneumonia have considerably higher Torque tenovirus (TTV) loads than do children with milder acute respiratory diseases (ARDs). Moreover, in children with ARDs, high TTV loads correlate with low percentages of circulating CD3+ and CD4+ T cells and with elevated percentages of B cells, suggesting that TTV might be immunomodulatory. Here, we show that, in children with ARDs, the presence of TTV and TTV load correlate with concentrations of serum eosinophil cationic protein. The possible mechanisms whereby TTV infection might lead to augmented activity of eosinophils and the implications for pathogenesis are discussed.

Acute Disease↗
PubMed2000

Estimation of torque on mechanical heart valves due to magnetic resonance imaging including an estimation of the significance of the Lenz effect using a computational model.

Mitral and aortic valve replacement is a procedure which is common in cardiac surgery. Some of these replacement valves are mechanical and contain moving metal parts. Should the patient in whom such a valve has been implanted be involved in magnetic resonance imaging, there is a possible dangerous interaction between the moving metal parts and the static magnetic field due to the Lenz effect. Mathematical models of two relatively common forms of single-leaflet valves have been derived and the magnitude of the torque which opposes the motion of the valve leaflet has been calculated for a valve disc of solid metal. In addition, a differential model of a ring-strengthener valve type has been considered to determine the likely significance of the Lenz effect in the context of the human heart. For common magnetic field strengths at present, i.e. 1 to 2 T, the effect is not particularly significant. However, there is a marked increase in back pressure as static magnetic field strength increases. There are concerns that, since field strengths in the range 3 to 4 T are increasingly being used, the Lenz effect could become significant. At 5 to 10 T the malfunction of the mechanical heart valve could cause the heart to behave as though it is diseased. For unhealthy or old patients this could possibly prove fatal.

Aortic Valve↗
PubMed1996

Initial stress differences between tipping and torque movements. A three-dimensional finite element analysis.

The aim of this study was to analyse the distribution of the stress on dental and periodontal structures when a simple tipping dental movement or torque movement is produced. A tridimensional computer model based on finite element techniques was used for this purpose. The model of the lower canine was constructed on the average anatomical morphology and 396 isoparametric elements were considered. The three principal stresses (maximum, minimum and intermediate) and Von Mises stress were determined at the root, alveolar bone and periodontal ligament (PDL). It was observed how the distribution of stress is not the same for the three structures studied. In all loading cases for bucco-lingually directed forces, the three principal stresses were very similar in the PDL. The dental apex and bony alveolar crest zones are the areas that suffer the greatest stress when these kind of movements are produced.

Alveolar Process↗
PubMed2005

A comparison of torque required to fracture rotary files with tips bound in simulated curved canal.

The purpose of this study was to compare torque force and rotation needed to fracture three types of nickel titanium alloy rotary instruments in a simulated curved root canal space that were bound at the file tip. Files of similar size tips were studied. The files studied were ProFiles with 0.04 taper diameters of 15, 20, 25, 30, 35, 40, 45; 0.04 ProFile GT sizes 20, 30, 40; and ProTaper files sizes S1, S2, F1, F2, and F3. All files were 25 mm in length. Unwinding was defined as the rotation in degrees it took for a file to fracture after the first evidence of permanent deformation. All files exhibited permanent deformation before breaking, with the ProFile GT files demonstrating the greatest unwinding. The #45 0.04 ProFile withstood the most force while the #20 ProFile GT required the least amount of force before beginning to exhibit permanent deformation. The S1 and S2 ProTaper files fractured with so little rotation that no extended data were recorded. Generally, as the file diameter increased, the force needed to begin unwinding also increased. Also, as the file diameter increased, the force needed to fracture also increased.

Analysis of Variance↗
PubMed2005

Rolling-circle amplification of Torque teno virus (TTV) complete genomes from human and swine sera and identification of a novel swine TTV genogroup.

Multiply primed rolling-circle amplification is a novel technology that uses bacteriophage phi29 DNA polymerase to amplify circular DNA molecules, without the need for prior knowledge of their sequences. In an attempt to detect Torque teno virus (TTV), rolling-circle amplification was used to amplify DNA extracted from eight human and four pig serum samples. All samples gave high molecular weight (>30 kb) amplification products. By restriction endonuclease digestion, these products generated DNA fragments whose sizes were consistent with those of human TTV (3.8 kb) and swine TTV (Sd-TTV; 2.9 kb) genomes. Two TTV isolates derived from a single AIDS patient, as well as two Sd-TTV isolates derived from a single pig, were characterized by complete nucleotide sequencing. One of the Sd-TTV isolates showed very low (43-45 %) nucleotide sequence similarity to the other Sd-TTV isolate and to the prototype isolate Sd-TTV31, and could be considered the prototype of a novel genogroup.

Adult↗
PubMed2006

Prevalence of swine Torque teno virus in post-weaning multisystemic wasting syndrome (PMWS)-affected and non-PMWS-affected pigs in Spain.

The present study was designed to investigate the prevalence of swine Torque teno virus (TTV) in post-weaning multisystemic wasting syndrome (PMWS)-affected and non-affected Spanish swine. Nested PCR (nPCR) assays to detect two distinct TTV genogroups were applied. A significantly higher prevalence of TTV infection was found in sera from PMWS-affected animals (97 %) than in sera from non-PMWS-affected animals (78 %). Whilst PMWS-affected pigs (91 %) were more likely to be infected with TTV from genogroup 2 than non-PMWS-affected swine (72 %), no such difference was observed with genogroup 1. Nucleotide sequences of nPCR products were 91-99 % identical between strains within a genogroup. In contrast, inter-genogroup sequence identities were 49-58 %. Phylogenetic analyses demonstrated that genogroups form different clusters without association with PMWS or porcine circovirus type 2 infection status of the animals. These results indicate a high prevalence of both swine TTV genogroups in Spain, being present more frequently in PMWS-affected animals than in non-PMWS-affected animals.

Animals↗
PubMed2004

Transcription rate of RNA polymerase under rotary torque.

We investigated the transcription rates of RNA polymerases that were subjected to rotational drag. By combining chemical kinetics with mechanical equations, we derived formulas for the transcription rate in the case where the torque was caused by the hydrodynamic drag to DNA rotation.

Computer Simulation↗
PubMed2026

Evaluating Associations Between Ankylosing Spondylitis, Torque Teno Virus and Polymorphisms in Interleukin 6 and Vitamin D Receptor Genes.

The etiology of ankylosing spondylitis (AS) is complex and not yet fully understood. Interleukin-6 (IL-6), vitamin D and the vitamin D receptor (VDR) play an important role in modulating immune response, and Torque teno virus is considered a marker of immune status. This case-control study aimed to investigate the predisposition to AS. A total of 85 patients with AS and 100 clinically healthy individuals were included. VDR polymorphisms (rs2228570, rs1544410, rs7975232, rs731236) were genotyped using the PCR-RFLP technique, while for the IL-6 -174 G>C (rs1800795) polymorphism the tetra-primer ARMS-PCR technique was used. The presence of TTV was detected using the hemi-nested PCR technique. Our findings indicate a statistically significant association between TTV and AS (p = 0.035). C allele of both rs1800795 polymorphism in main groups (p = 0.027) and rs731236 polymorphism in women subgroups (p = 0.036) may be linked to an increased susceptibility to AS. However, none of these associations reach statistical significance after Bonferroni correction. Furthermore, within female subgroups, a significant association was found between the T allele of rs1544410 polymorphism and AS (p = 0.000038, corrected p = 0.00076). A significant association was also observed between the TT genotype of rs2228570 polymorphism, TTV and AS (p = 0.029). Haplotype analysis revealed that certain VDR haplotypes may confer either a protective effect against AS or an increased risk of developing the condition. Notably, rs1544410 polymorphism or a linked polymorphism may influence AS susceptibility. In conclusion, our data suggest that TTV and VDR polymorphisms may be associated with an increased risk of developing AS, indicating that these markers could potentially be used in the future for earlier diagnosis and more targeted treatment of the disease.

Torque teno virus↗
PubMed2006

Detection of swine torque teno virus in Italian pig herds.

Anellovirus is a recently created, floating genus of viruses. Torque teno virus (TTV), the type species in the genus, was first discovered in a human patient with a post-transfusion hepatitis of unknown aetiology. Recently, TTV genetically related to but distinct from those discovered in humans have also been found in animals, including pigs. The aims of this study were to estimate the prevalence of swine TTV in Italian pig herds and some risk factors possibly associated with this infection. Serum samples from 179 healthy pigs from 10 farms located in north-central Italy were tested by polymerase chain reaction for the presence of swine TTV DNA. Viral DNA was found in the sera of 43 pigs (24.0%), coming from eight of the 10 farms examined. Prevalence was significantly higher in finishing herds (40.1%) than in farrow-to-finish herds (11.0%) and did not depend on the size of the herd. Within the finishing herds the prevalence was significantly higher in weaners (57.4%) than in fatteners (22.9%), but this difference was not observed in farrow-to-finish herds. No relationship was observed between the prevalence of swine TTV and the implementation of some general hygiene practices and biosecurity procedures within the herds.

Animal Husbandry↗
PubMed2006

Maxillary incisor torque with conventional and self-ligating brackets: a prospective clinical trial.

OBJECTIVES: To test the hypothesis that the engagement mode of wire to bracket affects the buccolingual inclination of maxillary incisors in extraction and non-extraction treatment with self-ligating and conventional brackets. DESIGN: A randomized clinical trial employing a random distribution of variables among the studied populations. SETTING AND SAMPLE POPULATION: Private practice of one author. A total of 105 patients followed prospectively, were divided into two groups based on the inclusion of extraction in the treatment planning. These groups were further divided in two subgroups each, one receiving a self-ligating bracket and the other treated with a conventional Edgewise appliance of the same slot size and prescription. EXPERIMENTAL VARIABLE: Difference in the buccolingual inclination of maxillary incisors before and after treatment with the two appliances across the two treatment groups (extraction and non-extraction). OUTCOME MEASURE: Angular measurements of the Sella-Nasion and Nasion-A point to maxillary incisor axis. RESULTS: No difference was found in the mean difference of the two angles measured for the two bracket groups studied. CONCLUSION: Self-ligating brackets seem to be equally efficient in delivering torque to maxillary incisors relative to conventional brackets in extraction and non-extraction cases.

Adolescent↗
PubMed2003

Axial rotation of the lower human spine by rhythmic torques automatically generated at the resonant frequency.

Subjects sat on a 'Balans' chair supported by the shaft of a large torque generator. The lower but not the upper part of the body was free to make to/fro movements maintained by feeding back a modified velocity signal to the generator. The stiffness could be increased by the use of a position signal. Using the equations for a torsion pendulum the good linearity observed in relationship to the applied forces allowed stiffness, inertia, damping, critical damping and the damping factor to be determined in absolute terms. The method enables parameters relevant to back function and problems to be evaluated. Eleven adults acted as subjects.

Biomechanical Phenomena↗
PubMed2005

Application of cation-coated filter method to detection of noroviruses, enteroviruses, adenoviruses, and torque teno viruses in the Tamagawa River in Japan.

The occurrence of human enteric viruses in surface water in the Tamagawa River, Japan, was surveyed for 1 year, from April 2003 to March 2004. Sixty-four samples were collected from six sites along the river, and 500 ml of the sample was concentrated using the cation-coated filter method, which was developed in our previous study. This method showed recovery yields of 56% +/- 32% (n = 37) for surface water samples inoculated with polioviruses. More than one kind of tested virus was detected in 43 (67%) of 64 samples by TaqMan PCR. Noroviruses and adenoviruses were detected in a high positive ratio; 34 (53%), 28 (44%), and 29 (45%) of 64 samples were positive for norovirus genotype 1 and genotype 2 and adenoviruses, respectively. The mean concentrations of norovirus genotype 1 or genotype 2 determined by real-time PCR were 0.087 and 0.61 genome/ml, respectively, showing much higher values in winter (0.21 genome/ml for genotype 1 and 2.3 genomes/ml for genotype 2). Enteroviruses were detected by both direct PCR (6 of 64 samples; 9%) and cell culture PCR (2 of 64 samples; 3%). Torque teno viruses, emerging hepatitis viruses, were also isolated in three samples (5%). The concentration of total coliforms and the presence of F-specific phages showed a high correlation with the presence of viruses, which suggested that the simultaneous use of total coliforms and F-specific phages as indicators of surface water may work to monitor viral contamination.

Adenoviridae↗
PubMed2004

The complex flagellar torque generator of Pseudomonas aeruginosa.

Flagella act as semirigid helical propellers that are powered by reversible rotary motors. Two membrane proteins, MotA and MotB, function as a complex that acts as the stator and generates the torque that drives rotation. The genome sequence of Pseudomonas aeruginosa PAO1 contains dual sets of motA and motB genes, PA1460-PA1461 (motAB) and PA4954-PA4953 (motCD), as well as another gene, motY (PA3526), which is known to be required for motor function in some bacteria. Here, we show that these five genes contribute to motility. Loss of function of either motAB-like locus was dispensable for translocation in aqueous environments. However, swimming could be entirely eliminated by introduction of combinations of mutations in the two motAB-encoding regions. Mutation of both genes encoding the MotA homologs or MotB homologs was sufficient to abolish motility. Mutants carrying double mutations in nonequivalent genes (i.e., motA motD or motB motC) retained motility, indicating that noncognate components can function together. motY appears to be required for motAB function. The combination of motY and motCD mutations rendered the cells nonmotile. Loss of function of motAB, motY, or motAB motY produced similar phenotypes; although the swimming speed was only reduced to approximately 85% of the wild-type speed, translocation in semisolid motility agar and swarming on the surface of solidified agar were severely impeded. Thus, the flagellar motor of P. aeruginosa represents a more complex configuration than the configuration that has been studied in other bacteria, and it enables efficient movement under different circumstances.

Bacterial Proteins↗
PubMed2001

Effect of number of stimuli and timing of twitch application on variability in interpolated twitch torque.

Application of a supramaximal electrical twitch to the voluntarily contracted muscle is used to assess the level of muscle activation. Large variability in the interpolated twitch torque (ITT) has been observed when repeated stimulations are performed. It is hypothesized that this variability in ITT is caused by the stochastic nature of the timing of twitch application relative to pulses of voluntary excitation trains. Two experiments were performed on 12 subjects each to test this hypothesis. For the first experiment, a single twitch was superimposed on a train stimulation at different time intervals relative to the train pulses. For the second experiment, single, double, triple, or quadruple twitches were applied on a voluntarily contracted muscle. The ITT critically depended on the time point of twitch application: a single pulse applied 5 ms before a train pulse consistently evoked higher ITTs than all other stimulation conditions. Furthermore, variability of the ITT decreased as the number of applied twitches increased. The results support the hypothesis that a large part of the variability in the ITT may be caused by the timing of the superimposed twitch relative to the motor unit trains. The variability may be reduced by increasing the number of superimposed twitches.

Adult↗
PubMed2005

Early plateaus of power and torque gains during high- and low-speed resistance training of older women.

Periodization is the most effective approach to resistance training; however, optimal cycle lengths for older persons are not known. This study examined the durations of performance increments, plateaus, and decrements in women, ages 61-75 yr, over 9 wk of isokinetic training. After a 2-wk adaptation cycle, older women trained for either power (PWR; 4.73 rad/s; n = 9) or strength (STR; 1.05 rad/s; n = 8), 3 days/wk with a 1-day recovery between sessions. Repetitions were initially selected to equilibrate work volume between groups. Average power (AP), peak torque (PT), and total work (TW) curves were analyzed using forward and backward stepwise regression to ascertain inflections and plateaus. PWR training produced the highest AP, whereas STR produced the highest PT. TW was similar between groups. The AP curves of the PWR group initially showed a steep positive slope and then plateaued during week 3. The right leg plateau lasted throughout training, whereas the left leg showed another positive inflection during weeks 7 and 8. PWR group TW curves showed positive slopes throughout training. STR group PT curves for both legs showed initial positive slopes peaking between weeks 3 and 4 and declining thereafter. The TW curves for both legs showed slight negative slopes across the first 2 wk, steep positive slopes during weeks 3-6, and a final plateau. Because improvements plateau early during PWR and STR training, isokinetic training prescriptions for optimizing strength and power improvements in older persons should use cycles of 3-4 wk to maximize gains.

Adaptation, Physiological↗