Value of Strain-Ratio Elastography in the Diagnosis and Differentiation of Uterine Fibroids and Adenomyosis

Benign uterine disorders, including uterine fibroids (UF) and adenomyosis (AM), can impact the life quality and fertility of women of reproductive age. Transvaginal ultrasound (TVUS) has long been used for their early identification, but its combined use with elastography seems to improve diagnostic accuracy of UF and AM. Thus, a prospective pilot study was conducted on 79 patients who underwent hysterectomy (25 microscopically diagnosed with AM and 53 with UF), with the aim of assessing the ability of TVUS combined with strain ratio elastography (SE) to accurately diagnose and distinguish UF and AM. Significantly higher mean and maximal strain ratio (SR) values were identified for patients with histologically confirmed AM as opposed to those with UF (p < 0.001). Diagnostic sensitivity and specificity, calculated in comparison with histology results, were higher for UF than AM. Receiver operating characteristic (ROC) analysis was applied between the two study groups, revealing cutoff values of 7.71 for mean SR and 8.91 for maximal SR, respectively, with good sensitivity and specificity parameters (100% and 96.23%; 96% and 96.23%). Our results support the use of TVUS in combination with SE for the positive and differential diagnosis of UF and AM, through identification of their particular tissue stiffness features.

Strain patterns in normal anterior talofibular and calcaneofibular ligaments and after anatomical reconstruction using gracilis tendon grafts: A cadaver study

Background Inversion ankle sprains, or lateral ankle sprains, often result in symptomatic lateral ankle instability, and some patients need lateral ankle ligament reconstruction to reduce pain, improve function, and prevent subsequent injuries. Although anatomically reconstructed ligaments should behave in a biomechanically normal manner, previous studies have not measured the strain patterns of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) after anatomical reconstruction. This study aimed to measure the strain patterns of normal and reconstructed ATFL and CFLs using the miniaturization ligament performance probe (MLPP) system. Methods The MLPP was sutured into the ligamentous bands of the ATFLs and CTLs of three freshly frozen cadaveric lower-extremity specimens. Each ankle was manually moved from 15° dorsiflexion to 30° plantar flexion, and a 1.2-N m force was applied to the ankle and subtalar joint complex. Results The normal and reconstructed ATFLs exhibited maximal strain (100) during supination in three-dimensional motion. Although the normal ATFLs were not strained during pronation, the reconstructed ATFLs demonstrated relative strain values of 16–36. During the axial motion, the normal ATFLs started to gradually tense at 0° plantar flexion, with the strain increasing as the plantar flexion angle increased, to a maximal value (100) at 30° plantar flexion; the reconstructed ATFLs showed similar strain patterns. Further, the normal CFLs exhibited maximal strain (100) during plantar flexion-abduction and relative strain values of 30–52 during dorsiflexion in three-dimensional motion. The reconstructed CFLs exhibited the most strain during dorsiflexion-adduction and demonstrated relative strain values of 29–62 during plantar flexion-abduction. During the axial motion, the normal CFLs started to gradually tense at 20° plantar flexion and 5° dorsiflexion. Conclusion Our results showed that the strain patterns of reconstructed ATFLs and CFLs are not similar to those of normal ATFLs and CFLs.

Tyrosine residues mediate supercontraction in biomimetic spider silk

Water and humidity severely affect the material properties of spider major ampullate silk, causing the fiber to become plasticized, contract, swell and undergo torsion. Several amino acid residue types have been proposed to be involved in this process, but the complex composition of the native fiber complicates detailed investigations. Here, we observe supercontraction in biomimetically produced artificial spider silk fibers composed of defined proteins. We found experimental evidence that proline is not the sole residue responsible for supercontraction and that tyrosine residues in the amorphous regions of the silk fiber play an important role. Furthermore, we show that the response of artificial silk fibers to humidity can be tuned, which is important for the development of materials for applications in wet environments, eg producing water resistant fibers with maximal strain at break and toughness modulus.

The prognostic value of myocardial deformational patterns is reduced in patients with heart failure

Background Early systolic lengthening (ESL) and postsystolic shortening are considered highly specific for myocardial ischemia. We aimed to investigate the prognostic potential of both deformational patterns in patients with heart failure (HF) and to determine if a history of ischemic heart disease modified this relationship. Method A total of 884 patients with systolic HF (66±12 years, male 73%, mean ejection fraction 28±9%) underwent speckle tracking echocardiography. Of these, 61% suffered from ischemic cardiomyopathy (ICM). Patients were followed for all-cause mortality. We assessed the ESL index: [−100x (peak positive strain/maximal strain)] and the postsystolic index (PSI): [100x (postsystolic strain/maximal strain)]. Both parameters were averaged across 18 myocardial segments. Results During a median follow-up of 3.4 years [interquartile range 1.9 to 4.8], 132 patients (15%) died. In multivariable survival analyses adjusted for potential confounders (age, sex, BMI, mean arterial pressure, cholesterol, heart rate, CABG/PCI, left ventricular ejection fraction and mass index, left atrial volume index, tricuspid annular plane systolic excursion, E-wave, E/e', deceleration time, and global longitudinal strain) neither the ESL index (HR 1.02 per 1% increase [0.97 to 1.08], P=0.40) nor PSI (HR 1.00 per 1% increase [0.98 to 1.01], P=0.69) were associated with all-cause mortality. ICM modified the relationship (P interaction unadjusted/adjusted=0.001/0.008; Figure) such that per 1% increase in ESL index in patients with ICM was significantly associated with all-cause mortality (unadjusted: HR 1.09 [1.04 to 1.15], P&lt;0.001 and adjusted: HR 1.06 [1.00 to 1.13], P=0.045) but not in those without (unadjusted: HR 1.02 [1.01 to 1.03], P=0.002 and adjusted: HR 0.99 [0.90 to 1.09], P=0.086). ICM did not modify the relationship between PSI and all-cause mortality (P interaction unadjusted/adjusted=0.15/0.13). Conclusion Our results indicate that in this cohort of undifferentiated HF patients with reduced ejection fraction the prognostic value of deformational patterns was reduced. However, the ESL index may provide some information on prognosis in patients with ICM. ESL and interaction with ICM Funding Acknowledgement Type of funding source: None

A DESCRIPTIVE STUDY OF MR DEFECOGRAPHY FOR EVALUATION OF OBSTRUCTED DEFECATION SYNDROME

Objective:-This study aims to ascertain the role of MR Defecography in the evaluation of obstructed defecation syndrome (ODS) with objective to describe spectrum of MR Defecography findings in obstructed defecation syndrome (ODS) and describe a number of reference lines and measurement points used to diagnose and grade pelvic floor disorders and Document the MRI appearance of disorders associated with ano-rectal dysfunction. MR Defecography demonstrated the profile of obstructed defecation syndrome on the basis of MR defecography and demonstrate its utility in simultaneous & objective evaluation of all three pelvic compartments. This diagnostic modalities provide a detailed pelvic floor anatomy and functional evaluation, as well as their respective abnormalities, making a precise diagnosis and provides valuable information on treatment planning & decrease chance of postoperative recurrence. Subjects and Methods: It was Cross-sectional and prospective (quantitative) hospital based descriptive type of observational study carried out at a tertiary hospital SMS hospital, jaipur. Chosen the patients diagnosed with ODS as per Rome criteria (III) whose colonoscopy or rectosigmoidoscopy, had been done to rule out other findings from Feb 2018 to September 2019.MR defecography (static and dynamic) with 3 T (PHILIPS INGENIA) MRI system having tunnel configuration. After written and informed consent, patient was positioned supine in MR machine gantry . Static imaging performed in the axial T1WI high resolution, axial, coronal and sagittal T2WI high resolution images at rest for anatomical evaluation. Following this,after ultrasound gel instilled in the patient’s rectum and intravaginaly ,dynamic imaging were taken in the midsagittal plane through the anal canal using a T2 weighted sequence. This sequence was ran for almost 2 min, while the patient performs various maneuvers (Kegel (squeeze), valsalva menuvere (strain), and defecation). MR defecography structurally and functionally evaluated in all 3 pelvic floor compartments and associated defects noted and grading of specific findings like organ specific prolapse, pelvic floor relaxiation and descent were measured. Results: In our study most common findings were pelvic floor descent and anorectal junction descent in 92.68% cases each followed by rectocele in 82.93% cases. Among the females, vaginal/uterine prolapse were observed in 65.31% cases. Least common findings were paradoxical contraction (8.54%) and sigmoidocele (0%). Significant difference was observed in MRI functional parameters in resting state and during defecation/maximal strain position, utilising HMO system for pelvic floor relaxation and descent, as significant difference (p <0.001S) was observed in all parameters including H line, M line, bladder base descent, cervical/vaginal and anorectal junction descent during resting state and during defecation/maximal strain position. Out of 82 conservative biofeedback therapy was given to 79.27 % patients, surgical management was done in (7.32%) and combination of both therapies was given in 13.41% of cases. Out of 82 patients 68.29% showed benefit from management and showed improvement on follow and 31.71% patients were not improved on follow up. Conclusion: As complete survey of the entire pelvis is necessary before surgical repair Magnetic resonance imaging permits evaluation of all three pelvic compartments and as we demonstrated in our study more than one compartment are frequently affected in obstructed defecation syndrome. Static MR Imaging can be also useful to identify the defects responsible for pelvic organ prolapse and stress urinary incontinence, and so help perform site specific repair in surgery, to avoid the high recurrence rates.Findings reported at dynamic MR imaging of the pelvic floor are valuable for selecting candidates for surgical treatment and for indicating the most appropriate surgical approach as detection rate of pathologies increased during defecation / maximal straning as concluded by our study.

Elastic properties and breaking strengths of GaS, GaSe and GaTe nanosheets

The present study highlights the elastic properties of suspended GaS, GaSe and GaTe nanosheets using atomic force microscopy. GaS exhibited the highest Young's modulus (∼173 GPa) among these nanosheets. These materials can withstand maximal stresses of up to 8 GPa and a maximal strain of 7% before breaking, making them suitable for stretchable electronic and optomechanical devices.

The Fluid Dynamical Performance of the Carpentier-Edwards PERIMOUNT Magna Ease Prosthesis

The aim of the present in vitro study was the evaluation of the fluid dynamical performance of the Carpentier-Edwards PERIMOUNT Magna Ease depending on the prosthetic size (21, 23, and 25 mm) and the cardiac output (3.6–6.4 L/min). A self-constructed flow channel in combination with particle image velocimetry (PIV) enabled precise results with high reproducibility, focus on maximal and local peek velocities, strain, and velocity gradients. These flow parameters allow insights into the generation of forces that act on blood cells and the aortic wall. The results showed that the 21 and 23 mm valves have a quite similar performance. Maximal velocities were 3.03±0.1 and 2.87±0.13 m/s; maximal strain Exx, 913.81±173.25 and 896.15±88.16 1/s; maximal velocity gradient Eyx, 1203.14±221.84 1/s and 1200.81±61.83 1/s. The 25 mm size revealed significantly lower values: maximal velocity, 2.47±0.15 m/s; maximal strain Exx, 592.98±155.80 1/s; maximal velocity gradient Eyx, 823.71±38.64 1/s. In summary, the 25 mm Magna Ease was able to create a wider, more homogenous flow with lower peak velocities especially for higher flow rates. Despite the wider flow, the velocity values close to the aortic walls did not exceed the level of the smaller valves.

Visualization of Processes of Plastic Deformation Initiation in Conditions of Pure Tension and Pure and Simple Bending

The rules and capabilities of macro-strains identification method with the use of optical interference for identifying initial phase of plastic deformation process in steels with material instability were discussed in the work. It was also shown how the technique run in presentation of the initial phase of yielding progress. As the example for illustration of discussed method real capabilities the course of plastic deformations beginning in the tension tests of 15CrMo and 34CrNiMo6 steel samples was shown as well as the course of test of pure and simple bending for the steel 15CrMo beam. Namely, the sequence of interference fringes pictures showing the formation of plastic strains correlating to the points on the tensile test curve was presented. For bending process the pictures were correlated with the point on the graph of dimensionless bending moment versus maximal strain measured by the strain gauge

Computational Analysis of Fluid Flow Within a Device for Applying Biaxial Strain to Cultured Cells

In vitro systems for applying mechanical strain to cultured cells are commonly used to investigate cellular mechanotransduction pathways in a variety of cell types. These systems often apply mechanical forces to a flexible membrane on which cells are cultured. A consequence of the motion of the membrane in these systems is the generation of flow and the unintended application of shear stress to the cells. We recently described a flexible system for applying mechanical strain to cultured cells, which uses a linear motor to drive a piston array to create biaxial strain within multiwell culture plates. To better understand the fluidic stresses generated by this system and other systems of this type, we created a computational fluid dynamics model to simulate the flow during the mechanical loading cycle. Alterations in the frequency or maximal strain magnitude led to a linear increase in the average fluid velocity within the well and a nonlinear increase in the shear stress at the culture surface over the ranges tested (0.5–2.0 Hz and 1–10% maximal strain). For all cases, the applied shear stresses were relatively low and on the order of millipascal with a dynamic waveform having a primary and secondary peak in the shear stress over a single mechanical strain cycle. These findings should be considered when interpreting experimental results using these devices, particularly in the case when the cell type used is sensitive to low magnitude, oscillatory shear stresses.

EFFECTS OF SIMVASTATIN ON FEMORAL BIOMECHANICS IN OVARIECTOMIZED RATS

Objective: To investigate the effect of simvastatin on the biomechanical characteristics of the femur in ovariectomized rats. Material and methods: Fifty-four female Sprague-Dawley rats, aged three months old, were randomly divided into three groups: sham-operated group ( SHAM; n = 18), ovariectomized group (OVX; n = 18), and ovariectomized with simvastatin treatment group (OVX+SIM; n = 18). Eight weeks after being ovariectomized, simvastatin was administered orally at 5 mg/kg each day in the OVX + SIM group. The animals were sacrificed at either four or 12 weeks after administration and femurs were obtained. Biomechanical parameters were measured by the three-point bending test. Results: There were no significant differences in the maximal strain and flexibility strain between the OVX and OVX + SIM groups at either four or 12 weeks after administration (p > 0.05). In contrast, significant differences in flexibility loading at four weeks and in maximal loading, flexibility loading, and the coefficient of bending ductility between the OVX and OVX + SIM groups at either four or 12 weeks (p < 0.05 and p < 0.01, respectively). Intergroup comparisons showed that maximal loading and flexibility loading have significant differences in the OVX + SIM group (p < 0.01). Conclusion: Simvastatin shows potential in promoting bone remodeling, changing bone micro-architecture, and influencing the integration and distribution ratio of organic and inorganic constituents in bone tissue of ovariectomized rats. In addition, a longer time of administration with simvastatin could enhance the femoral strength.