Twist Rate Research Articles

Expression and correlation of Twist and gelatinases in breast cancer

Altered expression of Twist, matrix metalloproteinase (MMP)-2 and MMP-9 proteins has been identified in various types of human cancers. However, the correlation between Twist and these gelatinases in breast cancer remains unclear. In this study, immunohistochemical analysis of Twist, MMP-2 and MMP-9 expression was performed on tissue microarrays from 200 breast cancer cases. The association of Twist and gelatinase expression with clinicopathological factors and patient survival was analyzed. Altered expression of Twist, MMP-2 and MMP-9 proteins was observed in breast cancer tissue. The positive rates of Twist, MMP-2 and MMP-9 protein expression were 75.5, 97.0 and 96.0%, respectively. Increased expression of Twist was positively correlated with the status of axillary lymph node metastasis and higher tumor-node-metastasis (TNM) stage (P<0.01). Moreover, increased expression of Twist was correlated with poor overall survival (OS) and post-operative relapse-free survival (RFS), compared with those for the patients with reduced expression levels of Twist (P<0.05, P<0.01). The expression of MMP-2 and MMP-9 was positively correlated with Twist expression (P<0.001). Our results indicate that Twist may play an important role in the invasion, metastasis and prognosis of breast cancer. Additionally, our results suggest that Twist may be a regulator of gelatinases (MMP-2 and MMP-9).

Prognostic significance of twist and N-cadherin expression in NSCLC.

BackgroundMetastasis is the most common cause of disease failure and mortality for non-small cell lung cancer after surgical resection. Twist has been recently identified as a putative oncogene and a key regulator of carcinoma metastasis. N-cadherin is associated with a more aggressive behavior of cell lines and tumors. The aim of this study was to evaluate the clinical relevance of Twist and N-cadherin expression in NSCLC, and the effects of Twist1 knockdown on lung cancer cells.MethodsWe examined the expressions of Twist and N-cadherin by immunohistochemistry in 120 cases of non-small cell lung cancer (including 68 cases with follow-up records). We also analyzed Twist1 and N-cadherin mRNA expression in 30 non-small cell lung cancer tissues using quantitative reverse transcription polymerase chain reaction. The functional roles of Twist1 in lung cancer cell lines were evaluated by small interfering RNA-mediated depletion of the protein followed by analyses of cell apoptosis and invasion.ResultsIn lung cancer tissues, the overexpression rate of Twist was 38.3% in lung cancer tissues. Overexpression of N-cadherin was shown in 40.83% of primary tumors. Moreover, Twist1 mRNA expression levels correlated with N-cadherin mRNA levels. Furthermore, overexpression of Twist1 or N-cadherin in primary non-small cell lung cancers was associated with a shorter overall survival (P<0.01, P<0.01, respectively). Depleting Twist expression inhibited cell invasion and increased apoptosis in lung cancer cell lines.ConclusionsThe overexpression of Twist and N-cadherin could be considered as useful biomarkers for predicting the prognosis of NSCLC. Twist1 could inhibit apoptosis and promote the invasion of lung cancer cells, and depletion of Twist1 in lung cancer cells led to inhibition of N-cadherin expression.

Niobium Nanowire Yarns and their Application as Artificial Muscles

AbstractMetal nanowires are twisted to form yarns that are strong (0.4 to 1.1 GPa), pliable, and more conductive (3 × 106 S m−1) than carbon nanotube yarns. Niobium nanowire fibers are extracted by etching a copper‐niobium nano‐composite material fabricated using the severe plastic deformation process. When impregnated with paraffin wax, the niobium (Nb) nanowire yarns produce fast rotational actuation as the wax is heated. The heated wax expands, untwisting the yarn, which then re‐twists upon cooling. Normalized to yarn length, 12 deg mm−1 of torsional rotation was achieved along with twist rates in excess of 1800 rpm. Tensile modulus of 19 ± 5 GPa was measured for the Nb yarns, which is very similar to those of carbon multiwalled nanotubes.

Optical activity in twisted solid-core photonic crystal fibers.

In this Letter we show that, in spectral regions where there are no orbital cladding resonances to cause transmission loss, the core mode of a continuously twisted photonic crystal fiber (PCF) exhibits optical activity, and that the magnitude of the associated circular birefringence increases linearly with twist rate and is highly reproducible. In contrast to previous work on twist-induced circular birefringence, PCF has zero linear birefringence and an on-axis core, making the appearance of circular birefringence rather unexpected. A theoretical model based on symmetry properties and perturbation theory is developed and used to show that both spin and orbital angular momentum play a role in this effect. It turns out that the degenerate left- and right-circularly polarized modes of the untwisted PCF are not 100% circularly polarized but carry a small amount of orbital angular momentum caused by the interaction between the core mode and the hollow channels.

Speckle‐tracking analysis based on 2D echocardiography does not reliably measure left ventricular torsion

Worldwide left ventricular (LV) twist is measured by 2D speckle tracking acquiring apical short axis at a LV level where papillary muscles are no longer visible; however, we hypothesized that this methodological recommendation is not enough accurate to obtain a reliable measurement of apical rotation. We measured twist and untwist rate in 30 healthy subjects by following the earlier method. By 3D echocardiography, we identified two LV apex levels: (i) 3D Apex, defined as the last apical slice at which LV cavity was visible; (ii) 2D Apex, defined as the level where diameters are equal to those of apical LV short axis used for twist analysis in the same subject. The ratio between the distance of 2D Apex and 3D Apex from LV base was calculated and expressed as percentage (2D Apex/3D Apex). 2D Apex/3D Apex was strongly related to the magnitude of twist and untwisting rate (r=0·82, P<0·001; r=-0·46, P=0·015, respectively). The only determinant of twist was 2D Apex/3D Apex (r(2) =0·68; r=0·82; F ratio: 52·6, P<0·001); whereas untwisting rate was influenced by 2D Apex/3D Apex and age (r(2) =0·42; r=0·65; F ratio: 7·7; P=0·003 for 2D Apex/3D Apex; and P=0·011 for age). Left ventricular apical level acquisition, even when recorded in a standard manner, determines variability of twist mechanics measurements. Thus, current anatomical markers used to identify LV apex for twist analysis are not reliable and need different standardization. 3D echocardiography may help in such standardization.

Aerodynamic Optimization Study of a Coaxial Rotor in Hovering Flight

A primary design goal with a coaxial rotor is to minimize the combined sources of losses on the upper and lower rotors that have their source in aerodynamic interference. To this end, parametric studies were conducted using a free-vortex wake method to study the aerodynamic interference effects of changing interrotor spacing, blade twist rates, and blade planform on the interdependent loads produced on the upper and lower rotors, respectively. A formal, multistep optimization process was then conducted by coupling the aerodynamic method to an optimization approach based on the method of feasible directions, the goal being to expeditiously find the individual blade geometries that would give the highest levels of efficiency from the coaxial as a system. Because of the inherent aerodynamic differences between the upper and lower rotors of a coaxial, it is shown that the best performing coaxial rotors may require the use of different blade shapes on each rotor, but substantially different blade designs may also achieve similar values of aerodynamic efficiency. It is also shown that the nonconvexity of the design problem for a coaxial rotor may limit the usefulness of formal optimization methods, and extensive parametric studies may still be required in the process of design.

Left ventricular twist in clinically stable heart transplantation recipients: A speckle tracking echocardiography study

Background and aimCavity twist is an integral part of LV function and its pattern in transplanted hearts is not well known. This study aimed at exploring LV twist in clinically stable heart transplant (HT) recipients with no evidence for rejection. MethodsWe studied 32 HT patients (54±24months after HT), 34 other cardiac surgery (CS) patients and compared them with 35 health controls using speckle tracking echocardiography, measuring peak twist angle, time-to-peak twist, and untwist rate. ResultsLV twist angle was smaller in the HT group (6.2±3.3°) in comparison with the CS group and controls (13.2±3.5° and 13.1±4.5°, respectively; p<0.0001 for all) and untwist rate was reduced (HT group: −74±30°/s; CS group: −118±43°/s; controls: −116±39°/s; p<0.0001 for all). Time-to-peak twist was not different between groups. Time after HT was the main independent predictor of both LV twist angle and untwist rate (β=0.8, p<0.0001). ConclusionThough clinically stable, LV twist dynamics are significantly impaired in HT recipients, even in comparison with patients who underwent other cardiac surgery.

Studies on various structural system design options for twisted tall buildings and their performances

SUMMARYEmploying twisted forms for tall buildings is a recent architectural phenomenon. This paper studies various structural system design options for twisted tall buildings and their performances based on lateral stiffness. Twisted tall buildings of various heights and rates of twist are designed with different types of contemporary tall building structural systems, such as diagrids, braced tubes and outrigger systems. The heights of the studied buildings range from 60 to 100 stories, and the rates of twist range from 0° to 3° per floor. As the rate of twist increases, the lateral stiffness of the tower decreases. The stiffness reduction rate caused by twisting is very much dependent upon the structural systems employed for twisted tall buildings. While an emphasis is placed on the structural performance of twisted tall buildings, other aspects, such as architectural and constructional issues, are also discussed holistically. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Prognostic value of Twist and E-cadherin in patients with osteosarcoma

Twist, a basic helix-loop-helix transcription factor, and E-cadherin are both correlated with the metastatic progression of several types of cancer. However, it is currently unknown whether their activations have relevance to the progression of osteosarcoma. The purpose of the present study was to investigate the clinicopathological and prognostic value of Twist and E-cadherin in osteosarcoma. Twist and E-cadherin expressions were determined by immunohistochemistry. Patient survival rates were determined by Kaplan-Meier method and log-rank test. Cox regression was adopted for multivariate analysis of prognostic factors. The positive rates of Twist and E-cadherin in 107 osteosarcoma specimens were 31.8 % (34/107) and 20.6 % (22/107), respectively. Twist expression was significantly correlated with that of E-cadherin (r = -0.209, P = 0.031). The positive expression of Twist and E-cadherin was significantly associated with metastasis in 107 osteosarcoma specimens (both P < 0.05). Patients with positive Twist expression had significantly poorer overall survival (OS; P < 0.05) and disease-free survival (DFS, P < 0.05) when compared with patients with the negative expression of Twist. Patients with positive expression of E-cadherin had significantly poorer OS (P < 0.05) when compared with patients with negative E-cadherin expression, but not a significantly poorer DFS (P = 0.081). On multivariate analysis, Twist expression and age were found to be independent prognostic factors for OS (both P < 0.05) and DFS (both P < 0.05). Our results suggest that Twist was expressed significantly more and E-cadherin significantly less in osteosarcoma with metastasis, and expression of both might be related to the prediction of metastasis potency and poor prognosis for patients with osteosarcoma.

Left ventricular twist is load-dependent as shown in a large animal model with controlled cardiac load

BackgroundLeft ventricular rotation and twist can be assessed noninvasively by speckle tracking echocardiography. We sought to characterize the effects of acute load change and change in inotropic state on rotation parameters as a measure of left ventricular (LV) contractility.MethodsSeven anesthetised juvenile pigs were studied, using direct measurement of left ventricular pressure and volume and simultaneous transthoracic echocardiography. Transient inflation of an inferior vena cava balloon (IVCB) catheter produced controlled load reduction. First and last beats in the sequence of eight were analysed with speckle tracking (STE) during the load alteration and analysed for change in rotation/twist during controlled load alteration at same contractile status. Two pharmacological inotropic interventions were also included to examine the same hypothesis in additionally conditions of increased and decreased myocardial contractility in each animal. Paired comparisons were made for different load states using the Wilcoxon’s Signed Rank test.ResultsThe inferior vena cava balloon occlusion (IVCBO) load change compared for first to last beat resulted in LV twist increase (11.67° ±2.65° vs. 16.17° ±3.56° respectively, p < 0.004) during the load alteration and under adrenaline stimulation LV twist increase 12.56° ±5.1° vs. 16.57° ±4.6° (p < 0.013), and though increased, didn’t reach significance in negative inotropic condition. Untwisting rate increased significantly at baseline from −41.7°/s ±41.6°/s vs.−122.6°/s ±55.8°/s (P < 0.039) and under adrenaline stimulation untwisting rate increased (−55.3°/s ±3.8°/s vs.−111.4°/s ±24.0°/s (p < 0.05), but did not systematically changed in negative inotropic condition.ConclusionsPeak systolic LV twist and peak early diastolic untwisting rate are load dependent. Differences in LV load should be included in the interpretation when serial measures of twist are compared.

Piezoelectric d 15 shear-response-based torsion actuation mechanism: An exact 3D Saint-Venant type solution

This paper is concerned with the detailed analysis of the behavior of a piezoceramic bi-morph torsion actuator using the d 15-effect. The bi-morph actuator is made of two oppositely polarized adjacent piezoceramic prismatic beams. The mathematical analysis is based on the Saint-Venant torsion theory; a formulation of the electromechanically coupled problem in terms of a stress function and of the electric potential is derived, which represents an exact solution of a specific three-dimensional problem; in particular, for the case when the axial stress and the axial component of the electric displacement vector are independent of the axial coordinate. The resulting boundary-value problem in the cross-section is solved using the method of finite differences. Solutions for the actuated rate of twist are presented and compared to three-dimensional electromechanically coupled finite element solutions using ABAQUS® for the case of a cantilevered bi-morph actuator. A very good agreement is found.

Twist expression associated with the epithelial-mesenchymal transition in gastric cancer

This study aimed to investigate the expression of Twist in gastric cancer tissues and its correlation between Twist and the epithelial-mesenchymal transition (EMT). By means of RT-PCR and Western blot, the mRNA and protein expressions of Twist, E-cadherin, and Vimentin in 61 gastric cancer tissues and adjacent normal tissues were detected. The positive rates of Twist, E-cadherin, and Vimentin mRNA expression in gastric cancer tissues were 73.9. 40.6, and 60.9 %, respectively; compared to the expression of these genes in adjacent normal tissues (2.9, 75.4, and 27.5 %), the differences were significant (p < 0.05). The E-cadherin protein expression level in gastric cancer tissues was significantly lower than that in the adjacent normal tissues (p < 0.05). After the transfection of Twist siRNA into the MKN45 cells, the protein expression of Twist was significantly reduced (p < 0.05), the protein expression of E-cadherin was significantly increased, and the number of cells that passed through the Transwell chamber was significantly lower than that in the non-transfected control group as well as the transfected control group (p < 0.05). Twist may be associated with the epithelial-mesenchymal transition in gastric cancer and the tumorigenesis, invasion, and metastasis of gastric cancer.

Expression and Significance of Twist, E-Cadherin, and N-Cadherin in Gastrointestinal Stromal Tumors

Twist, a basic helix-loop-helix transcription factor, has been reported to play a key role in the metastatic progression of several types of cancer. To investigate the expression and clinical significance of Twist, E-cadherin, and N-cadherin in gastrointestinal stromal tumors (GISTs). The expression of Twist, E-cadherin, and N-cadherin in GISTs was determined by immunohistochemistry, and their relationship with clinicopathological characteristics was analyzed. The positive rates of Twist, E-cadherin, and N-cadherin in GISTs were 66.7 % (52/78), 35.9 % (28/78), and 75.6 % (59/78), respectively. Twist was expressed significantly more in GISTs with distant metastasis or local invasion (p < 0.05). Although E-cadherin was expressed significantly less in cases of GISTs with distant metastasis (p < 0.05), expression of N-cadherin did not differ significantly according to clinical and pathological characteristics (p > 0.05). Expression of Twist was correlated positively with E-cadherin (rs = -0.253, p = 0.026) and negatively with N-cadherin (rs = 0.245, p = 0.030). Twist was expressed significantly more and E-cadherin significantly less in GISTs with metastasis, and expression of both was closely related to metastasis of GISTs.

Exercise Response in Hypertrophic Cardiomyopathy

Background— Abnormal left ventricular (LV) deformational mechanics have been demonstrated in patients with hypertrophic cardiomyopathy (HCM) at rest, but there is a lack of information on their adaptation to exercise. The aim of this study was to assess the adaptability of LV strains and torsional mechanics during exercise in HCM patients. Methods and Results— Twenty nonobstructive HCM patients (age, 48.3±12.3 years; 14 men) and 20 control subjects underwent speckle-tracking echocardiographic measurement of longitudinal, radial, and circumferential strains, systolic twist, and diastolic untwisting rate (UTR) at rest and submaximal exercise. HCM patients showed lower resting longitudinal (−15.7±5.0% versus −19.4±2.6%, P &lt;0.001) and radial (38.1±11.3% versus 44.7±14.4%, P &lt;0.05) strains but higher circumferential strain (−21.9±4.0% versus −18.8±2.3%, P &lt;0.05) and twist (15.7±3.6° versus 9.3±2.6°, P &lt;0.0001) than control subjects. Exercise induced an increase in all strains in control subjects but only a moderate increase in longitudinal strain (to −18.4±5.0%), without significant changes in radial and circumferential strains or twist in HCM patients. Exercise peak UTR was lower (−119.0±31.5°/s versus −137.3±41.1°/s) and occurred later (137±18% versus 125±11% systolic time, P &lt;0.05) in HCM than in control subjects. A significant relationship between twist and UTR was obtained in control subjects (ß=−0.0807, P &lt;0.001) but not in HCM patients (ß=−0.0051, P =0.68). Conclusions— HCM patients had severely limited strain adaptability and no LV twisting reserve at exercise. They had reduced and delayed UTR with reduced systolic-diastolic coupling efficiency by twist-untwist mechanics.

A new modeling approach for the dynamics of a micro end mill in high-speed micro-cutting

This study presents a distributed parameter model for the transverse vibration analysis of a micro end mill. Owing to its geometrical nonuniformity, the micro end mill is spatially sub-structured into three distinct spinning elastic systems. With the application of the extended Hamilton’s principle to the energy expressions of the spinning elastic systems, the governing equations of each sub-structured system are obtained. The overall analytical model incorporates a number of nonclassical structural effects that range from rotary inertia, shear deformation, taper ratio, to the rate of twist. For detailed frequency analyses, systematic solution of the elastodynamics governing equations is provided with the spectral finite element method. To assess the accuracy of the presented method, the frequency values of each of the spatial sub-structure are validated through available results in the literature. In the same vein, the solution of the entire ensemble of the distributed parameter system compares well with ANSYS® simulation. The investigation reveals the spinning rate to have the most significant effect on the frequency value of the micro tool followed by the taper ratio and the complex geometry of the micro flute.

Temperature- and strain-insensitive torsion sensor based on phase-shifted ultra-long-period grating

A temperature- and strain-insensitive torsion sensor is proposed and demonstrated by utilising a phase-shifted ultra-long-period grating. Experimental results demonstrate that the separation of phase shift resonant peaks changes with the twist rate, but remains invariant with the temperature or strain changes. In addition, it was found that the influence of twisting to the fibre grating is non-uniform along the fibre axis.

Quantitative assessment of systolic and diastolic left ventricular twist using Fourier Analysis of STimulated echoes (FAST) and CSPAMM

Summary The FAST method for measuring left ventricular twist has been expanded to semi-automatically measure torsion, peak systolic twist rate, peak diastolic untwisting rate, time to peak twist, and duration of untwisting using FAST+CSPAMM. Background Alterations in left ventricular (LV) twist are important for many pathologies including aortic stenosis[1], diastolic dysfunction[2] and aging[3]. LV twist is a measure of the rotation of the apex relative to the base of the heart. Employing a previously validated method, Fourier Analysis of STimulated echoes (FAST)[4], which measures object rotation directly in Fourier space, we performed quantitative analysis of LV twist, torsion, twisting rates, time to peak twist, and duration of untwisting in thirteen (n=13) healthy volunteers using SPAMM and CSPAMM[5] tagged images. FAST analysis typically requires 2-3 minutes of user interaction time. Methods A spoiled gradient echo pulse sequence was modified to support CSPAMM and used to acquire short-axis images in healthy volunteers (n=13) at the LV base and apex with the following parameters: 360-300x300280mm FOV, 5-6mm slice thickness, 192x144 acquisition matrix, 501 Hz/pixel receiver bandwidth, TE/ TR=3.5-3.7/4.7-6.5ms, 10mm tag spacing, 7-8 ky-lines per segment, 3/4 partial Fourier imaging, 14-16 cardiac phases, 15° FA and two averages for SPAMM imaging, and non-linearly ramped imaging flip angles (initial angle 22°) for CSPAMM[6]. Estimates of LV rotation at basal and apical slice levels for all frames were obtained from the rotation of the stimulated echo and stimulated anti-echo about the FID in Fourier Space using the FAST method[4]. Bland-Altman analysis, linear regression, paired t-test, and Wilcoxon signed-rank test were used to compare FAST+CSPAMM to a previously validated FAST+SPAMM technique. Only data obtained during the first 500ms was used for comparison of SPAMM and CSPAMM due to tag fading. P<0.01 was considered statistically significant. Results The comparison of FAST+CSPAMM to FAST+SPAMM for twist, torsion, twisting rates, time of peak twist and duration of untwisting are summarized in Table 1. Table 2 provides peak rotation and time to peak rotation for systole and diastole for the apical and basal slices, which are important metrics in aortic stenosis[1] and aging[3]. No significant differences were found for twist, torsion, or twist rate measurements made with FAST+CSPAMM to FAST+SPAMM using the paired ttest or the Wilcoxon signed-rank test. Bland-Altman analysis and linear regression demonstrate excellent agreement between techniques (Table 1). These values match well with literature[7]. Conclusions The FAST+CSPAMM is a semi-automated method that provides a quick and quantitative assessment of systolic and diastolic left ventricular twist, torsion, and twisting rates. When FAST is used in conjunction with CSPAMM duration of untwisting can be measured, which may provide further insight into left ventricular diastolic dysfunction.

An investigation on the effects of twist on geometry of the electrospinning triangle and polyamide 66 nanofiber yarn strength

The formation of a symmetric electrospinning triangle zone (E-triangle) via a technique based on using two oppositely charged nozzles is described for fabricating continuous twisted nanofiber yarn of polyamide (Nylon 66). This study shows how changing the dimensions and geometry of the E-triangle influences the distribution of nanofiber tension and diameter in this zone, and consequently how it affects the nanofiber yarn strength. The twist effect on the E-triangle geometry was investigated by changing the rotational speed of the twister plate of values of 96, 160, 224 and 288 rpm. The results showed that by increasing the twist rate, the apex angle of the E-triangle increased, whereas the height and width of the Etriangle decreased. An energy method was adopted to study the distribution of tension on nanofibers in the E-triangle. Considering a constant spinning tension, it was observed that the gradient of the nanofiber tension curve was steeper and the extreme values of tension on nanofibers were increased by increasing the twist rate. Furthermore, the mean diameter reduction of nanofibers confirmed these results. It is concluded that mechanical properties of nanofiber yarn have been considerably improved by increasing the twist rate and changing the shape of the E-triangle.

Wave propagation characteristics of a twisted micro scale beam

Twisted structural elements are inherently complex and their use in engineering systems requires deeper understanding. In this paper, starting with the modified couple stress theory, the elastodynamics governing partial differential equations of motion for the transverse dynamics of a twisted micro scale beam is derived. A micro scale beam of rectangular cross-section, for which the rate of twist introduced a bending–bending coupling effect, is considered. The presented governing equation of motion is used to address the effects of the rate of twist and the material length scale on the bending wave propagation characteristics of the micro scale beam. Results are presented for the spectrum curve, the cut-off frequency, the phase speed and the group velocity of a propagating harmonic wave profile in the twisted micro scale beam. It is observed that the rate of twist bifurcates the spectrum curve of the micro scale beam within a given frequency range, while the material length scale improves the dispersion of the traveling wave. The cut-off frequency is found to be independent of the material length scale, but proportional to the fourth power of the rate of twist. Increasing the material length scale is further observed to increase the group velocity of the wave, while a high rate of twist lowers the wave speeds.

Torsion sensing characteristics of fibre ring laser based on nonlinear polarisation rotation

A fibre active sensor based on fibre laser using nonlinear polarisation rotation is proposed and experimentally demonstrated. The laser wavelength strongly depended on polarisations, and the torsion sensing characteristics were investigated by twisting a section of polarisation-maintaining fibre which was incorporated into the laser ring cavity. It was observed that the change of laser wavelength with twist rate contained two stages. The laser wavelength had quasi-linear and periodic relationship with the twist rate in the first and second stage, respectively. There was a linear region in each period of the second stage. Utilising the active sensing method can realise high sensitivity torsion sensing measurement in the linear regions.