Serial Changes in Ventricular Strain in Symptomatic Obstructive Hypertrophic Cardiomyopathy Treated With Mavacamten: Insights From the VALOR-HCM Trial.

BACKGROUND: In severely symptomatic patients with obstructive hypertrophic cardiomyopathy, VALOR-HCM (A Study to Evaluate Mavacamten in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy Who Are Eligible for Septal Reduction Therapy) demonstrated that mavacamten reduces the need for septal reduction therapy with sustained improvement in left ventricular (LV) outflow tract gradients and symptoms. Global longitudinal strain (GLS), a measure of regional myocardial function, is a more sensitive marker of systolic function. In VALOR-HCM, we assessed serial changes in LV and right ventricular (RV) strain. METHODS: VALOR-HCM included 112 patients with symptomatic obstructive hypertrophic cardiomyopathy (mean, 60 years; 51% male; LV ejection fraction, 68%). Patients assigned to mavacamten at baseline continued the drug for 56 weeks (n=56) and those assigned to placebo (n=52) transitioned to mavacamten from weeks 16 to 56 (40-week exposure). LV-GLS and RV-GLS assessment was performed using a vendor-neutral software. Non-foreshortened apical (4-, 3-, and 2-chamber) views were used to obtain peak LV-GLS. RV focused 4-chamber view was used to calculate RV 4-chamber and free wall strain. A more negative strain value is favorable. RESULTS: At baseline, the mean LV-GLS, RV 4-chamber, and free wall strain values were -14.7%, -22.2%, and -16.8%, respectively (all worse than reported normal means). In the total study sample, LV-GLS significantly improved from baseline to week 56 (P=0.02). Twelve patients had transient reduction in LV ejection fraction (<50%) requiring temporary drug interruption (including 3 permanent discontinuations). The LV-GLS in this subgroup was worse at baseline versus total study population (-11.4%), with no significant worsening from baseline through week 56 (P=0.64). Both free wall and 4-chamber RV-GLS remained unchanged from baseline to week 56 (P=0.62 and P=0.56, respectively). CONCLUSIONS: In VALOR-HCM, treatment with mavacamten improved LV-GLS from baseline through week 56 (with no significant worsening of LV-GLS in patients with a reduction in LV ejection fraction ≤50%), suggesting a favorable long-term impact on regional LV systolic function. Additionally, there was no detrimental impact on RV systolic function. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04349072.

A simplified approach to discriminate between healthy subjects and patients with heart failure using cardiac magnetic resonance myocardial deformation imaging.

Aims: Left ventricular global longitudinal strain (LV-GLS) shows promise as a marker to detect early heart failure (HF). This study sought to (i) establish cardiac magnetic resonance imaging (CMR)-derived LV-GLS cut-offs to differentiate healthy from HF for both acquisition-based and post-processing techniques, (ii) assess agreement, and (iii) provide a method to convert LV-GLS between both techniques. Methods and results: A secondary analysis of a prospective study enrolling healthy subjects (n = 19) and HF patients (n = 56) was conducted. LV-GLS was measured using fast strain-encoded imaging (fSENC) and feature tracking (FT). Receiver operating characteristic (ROC) analyses were performed to derive and evaluate LV-GLS cut-offs discriminating between healthy, HF with mild deformation impairment (DI), and HF with severe DI. Linear regression and Bland-Altman analyses assessed agreement. Cut-offs discriminating between healthy and HF were identified at -19.3% and -15.1% for fSENC and FT, respectively. Cut-offs of -15.8% (fSENC) and -10.8% (FT) further distinguished mild from severe DI. No significant differences in area under ROC curve were identified between fSENC and FT. Bland-Altman analysis revealed a bias of -4.01%, 95% CI -4.42, -3.50 for FT, considering fSENC as reference. Linear regression suggested a factor of 0.76 to rescale fSENC-derived LV-GLS to FT. Using this factor on fSENC-derived cut-offs yielded rescaled FT LV-GLS cut-offs of -14.7% (healthy vs. HF) and -12% (mild vs. severe DI). Conclusion: LV-GLS distinguishes healthy from HF with high accuracy. Each measurement technique requires distinct cut-offs, but rescaling factors facilitate conversion. An FT-based LV-GLS ≥ -15% simplifies HF detection in clinical routine.

Virulence of Burkholderia pseudomallei ATS2021 Unintentionally Imported to United States in Aromatherapy Spray.

In the United States in 2021, an outbreak of 4 cases of Burkholderia pseudomallei, the etiologic agent of melioidosis and a Tier One Select Agent (potential for deliberate misuse and subsequent harm), resulted in 2 deaths. The causative strain, B. pseudomallei ATS2021, was unintentionally imported into the United States in an aromatherapy spray manufactured in India. We established that ATS2021 represents a virulent strain of B. pseudomallei capable of robust formation of biofilm at physiologic temperatures that may contribute to virulence. By using mouse melioidosis models, we determined median lethal dose estimates and analyzed the bacteriologic and histopathologic characteristics of the organism, particularly the potential neurologic pathogenesis that is probably associated with the bimABm allele identified in B. pseudomallei strain ATS2021. Our data, combined with previous case reports and the identification of endemic B. pseudomallei strains in Mississippi, support the concept that melioidosis is emerging in the United States.

Allylic Epoxides Increase the Strain Energy of Cyclic Olefin Monomers for Ring-Opening Metathesis Polymerization.

Ring-opening metathesis polymerization (ROMP) is an effective method for synthesizing functional polymers, but since the technique typically relies on high ring strain cyclic olefins, the most common monomers are norbornene derivatives. The reliance on one class of monomer limits the obtainable properties of ROMP polymers. In this work, we investigate new bicyclic monomers synthesized via epoxidation of commercial dienes. DFT estimates of these monomers' ring strains suggests a significant increase in strain for cyclic olefins containing allylic epoxides. We found that the eight-membered (3,4-COO) and five-membered (CPO) cyclic olefins were particularly effective for ROMP. CPO was of especially intriguing due to its excellent polymerizability when compared to the limited reactivity of other five-membered rings. Unlike polynorbornenes, the resulting polymers of both monomers displayed glass transition temperatures well below room temperature. Interestingly, poly(3,4-COO) showed both high stereo- and regioregularity while poly(CPO) showed little regularity. Both polymers could be readily modified via post-polymerization ring-opening of the reactive allylic epoxides. With a high epoxide density in poly(CPO), CPO is an exciting new ROMP monomer that is easily synthesized, can be polymerized to high conversion at room temperature, and may be facilely modified to yield a wide range of functional materials.

Superior Piezo-/Ferro-Electricity in Antiferroelectric AgxNbO3-δ Thin Films by Nanopillar Local Structure Design.

Antiferroelectrics are fundamental mother compounds critical in developing innovative lead-free piezoelectrics and ferroelectrics and hold great promise for wide-ranging applications in energy conversion and electronic devices. However, harnessing their superior properties presents a significant challenge due to the delicate balance required between their various states. In this study, through the unique design of nanopillar structures to alleviate the local polar heterogeneity, we have achieved significantly improved piezo-/ferro-electricity in classic lead-free antiferroelectric AgxNbO3-δ (x = 1, 0.9, and 0.8) epitaxial thin films. The effective piezoelectric coefficient reaches 440 pm V-1, 1 order of magnitude larger than the stoichiometric AgNbO3, rivaling classic lead zirconate titanate piezoelectrics. Atomic-scale electron microscopy investigations unravel the underlying mechanisms. The nanopillars, characterized by antisite occupancy of both Ag and Nb atoms and forming out-of-phase boundaries with the matrix, reduce the local crystal symmetry via interphase strain. This leads to the creation of flexible multinanodomain structures that significantly facilitate polarization rotation, thus substantially enhancing the piezoelectric performance. This study demonstrates the feasibility of engineering local heterogeneity through nanopillar design, offering a generally applicable method for property improvement of a wide range of antiferroelectrics.

Echocardiography for Management of Cardiovascular Disease in Pregnancy.

PURPOSE OF REVIEW: Cardiovascular disease (CVD) continues to be a leading contributor to maternal mortality and morbidity. Echocardiography is an essential tool for patients with suspected and known CVD to establish symptom etiology, treatment strategy, and prognosis. We summarize the current status of conventional and novel techniques for assessment of CVD during pregnancy. RECENT FINDINGS: Conventional techniques are still useful for evaluation of known or suspected CVD. Advanced technology using speckle tracking continues to evolve and is increasingly applied for diagnosis of subclinical disease including hypertensive disorders of pregnancy and left ventricular (LV) dysfunction. Precise recommendations on how frequently echocardiography should be performed and for whom remain in flux. However, a recently published consensus statement and new screening tool for pregnancy assessment of patients with valvular heart disease provide additional advice on using this modality. Echocardiography remains the diagnostic modality of choice for evaluation and risk stratification in pregnancy.

Biaxial Strain Transfer in Monolayer MoS2 and WSe2 Transistor Structures.

Monolayer transition metal dichalcogenides are intensely explored as active materials in 2D material-based devices due to their potential to overcome device size limitations, sub-nanometric thickness, and robust mechanical properties. Considering their large band gap sensitivity to mechanical strain, single-layered TMDs are well-suited for strain-engineered devices. While the impact of various types of mechanical strain on the properties of a variety of TMDs has been studied in the past, TMD-based devices have rarely been studied under mechanical deformations, with uniaxial strain being the most common one. Biaxial strain on the other hand, which is an important mode of deformation, remains scarcely studied as far as 2D material devices are concerned. Here, we study the strain transfer efficiency in MoS2- and WSe2-based flexible transistor structures under biaxial deformation. Utilizing Raman spectroscopy, we identify that strains as high as 0.55% can be efficiently and homogeneously transferred from the substrate to the material in the transistor channel. In particular, for the WSe2 transistors, we capture the strain dependence of the higher-order Raman modes and show that they are up to five times more sensitive compared to the first-order ones. Our work demonstrates Raman spectroscopy as a nondestructive probe for strain detection in 2D material-based flexible electronics and deepens our understanding of the strain transfer effects on 2D TMD devices.

Deformation dynamics of nanopores upon water imbibition.

Capillarity-driven transport in nanoporous solids is widespread in nature and crucial for modern liquid-infused engineering materials. During imbibition, curved menisci driven by high negative Laplace pressures exert an enormous contractile load on the porous matrix. Due to the challenge of simultaneously monitoring imbibition and deformation with high spatial resolution, the resulting coupling of solid elasticity to liquid capillarity has remained largely unexplored. Here, we study water imbibition in mesoporous silica using optical imaging, gravimetry, and high-resolution dilatometry. In contrast to an expected Laplace pressure-induced contraction, we find a square-root-of-time expansion and an additional abrupt length increase when the menisci reach the top surface. The final expansion is absent when we stop the imbibition front inside the porous medium in a dynamic imbibition-evaporation equilibrium, as is typical for transpiration-driven hydraulic transport in plants, especially in trees. These peculiar deformation behaviors are validated by single-nanopore molecular dynamics simulations and described by a continuum model that highlights the importance of expansive surface stresses at the pore walls (Bangham effect) and the buildup or release of contractile Laplace pressures as menisci collectively advance, arrest, or disappear. Our model suggests that these observations apply to any imbibition process in nanopores, regardless of the liquid/solid combination, and that the Laplace contribution upon imbibition is precisely half that of vapor sorption, due to the linear pressure drop associated with viscous flow. Thus, simple deformation measurements can be used to quantify surface stresses and Laplace pressures or transport in a wide variety of natural and artificial porous media.

PNIPAA-based temperature responsive ionic conductive hydrogels for flexible strain and temperature sensing.

Conductive hydrogels have received much attention in the field of flexible wearable sensors due to their outstanding flexibility, conductivity, sensitivity and excellent compatibility. However, most conductive hydrogels mainly focus on strain sensors to detect human motion and lack other features such as temperature response. Herein, we prepared a strain and temperature dual responsive ionic conductive hydrogel (PPPNV) with an interpenetrating network structure by introducing a covalent crosslinked network of N-isopropylacrylamide (NIPAAm) and 1-vinyl-3-butylimidazolium bromide (VBIMBr) into the skeleton of the hydrogel composed of polyvinylalcohol (PVA) and polyvinylpyrrolidone (PVP). The PPPNV hydrogel exhibited excellent anti-freezing properties (-37.34 °C) and water retention with high stretchability (∼930 %) and excellent adhesion. As a wearable strain sensor, the PPPNV hydrogel has good responsiveness and stability to a wide range of deformations and exhibits high strain sensitivity (GF=2.6) as well as fast response time. It can detect large and subtle body movements with good signal stability. As wearable temperature sensors, PPPNV hydrogels can detect human physiological signals and respond to temperature changes, and the volumetric phase transition temperature (VPTT) can be easily controlled by adjusting the molar ratio of NIPAAm to VBIMBr. In addition, a bilayer temperature-sensitive hydrogel was prepared with the temperature responsive hydrogel by two-step synthesis, which shows great promising applications in temperature actuators.

A description of lineage 1 Mycobacterium tuberculosis from papua, Indonesia.

Indonesia has the third highest number of tuberculosis (TB) patients infected with Mycobacterium tuberculosis (MTB) Lineage 1 (L1). Most of these MTB L1 cases can be found in Indonesia's remote easternmost province of Papua, one of Indonesia's most underdeveloped provinces with a particularly high burden for TB. In this study, we sequenced and described 42 MTB L1 isolates from a well-characterized cohort of patients. We found a genetically diverse MTB L1 population with no association between pathogen genetic relatedness and place of residence or pathogen genetic relatedness and patient ethnicity, which could reflect mixing between different locales and ethnicities or our low sampling fraction. Only a small number showed genetic variants associated with drug resistance (5/42, 11.9 %), probably due to a lack of effective treatment programs. The Papuan isolates showed similarities to other Island Southeast Asian Countries due to the high proportion of L1.2.1.2.1 (30/42, 71.4 %), especially East Timor and the Philippines. This study fills a research gap of MTB L1 in Indonesian Papua and should serve as a stepping stone for further research in the region.

Notch-insensitive, tough and self-healing conductive bacterial cellulose nanocomposite hydrogel for flexible wearable strain sensor.

To date, conductive hydrogels as an alternative to traditional rigid metallic conductors have attracted much attention in the field of flexible wearable electronic devices due to their inherent characteristics. Herein, a conductive bacterial cellulose (BC) nanocomposite hydrophobic-association (HA) hydrogel with highly stretchable, strong, self-healing, and notch-insensitive was fabricated by introducing the hydrophobic association. The obtained BCNC HA hydrogel shows excellent mechanical properties (~ 2400 % of stress and ~ 0.35 MPa of mechanical strength), superior notch-insensitive property with a fracture energy of ~38 KJ.m-2, and good self-healing property (healing efficiency of ~97 %). In addition, the hydrogel exhibits excellent ionic conductivity of ~1.90 S.m-1 and high sensing sensitivity toward tensile deformation. The wearable strain sensor based on this material is assembled can detect both large-scale motions and subtle body motions in real time, which show excellent durability (1000 cycles with the strain of 30 %). Thus, the BCNC HA hydrogels have promising potential in various wearable flexible electronic devices for artificial intelligence and human-machine interface applications in the future.

The association between leisure-time physical activity and cardiorespiratory and muscular fitness and job strain-Study with a Northern Finland birth cohort of 1966.

Job strain is a major concern in the workplace. Work-related stress is an increasing challenge worldwide as it is the leading cause of long-term sickness absences, disability pensions and lower productivity. Rarely studied simultaneously, both leisure-time physical activity (LTPA) and physical fitness (PF), which comprises cardiorespiratory fitness (CRF) and muscular fitness (MF), may have potential in preventing and managing job strain. The current study aimed to investigate whether LTPA, CRF and MF predict perceived job strain. In addition, the study examines reverse associations, that is, whether job strain predicts LTPA, CRF and MF. We used longitudinal population-based data from a Northern Finland birth cohort of 1966 (n = 5363) to analyse LTPA, CRF and MF as well as job strain and its components, job demands and job control, at age 31 years (1997) and 46 years (2012). Leisure-time physical activity was measured with a self-reported questionnaire whereas CRF and MF were measured as part of clinical examination. Linear regression analyses were used to analyse the data. In both men (n = 2548) and women (n = 2815), higher baseline MF predicted lower job strain and job demands 15 years later. In women, higher baseline total LTPA predicted higher job demands, whereas in men, higher CRF predicted lower job strain and higher job control. These associations remained significant, also when adjusted for education and occupational status. In the analyses on reverse associations, higher job control and higher job demands were linked to higher leisure-time moderate-to-vigorous physical activity (MVPA) and total LTPA 15 years later among both men and women, except for the association between job demands and total LTPA among women. These associations remained significant after adjustment for education and occupational status, except for the association of job control with MVPA and total LTPA among men. The association of higher job demands and total LTPA became significant in women. We conclude that LTPA and PF seem beneficial in preventing and managing job strain.

Association of left atrial function with frailty: The Atherosclerosis Risk in Communities (ARIC) study.

BACKGROUND: Frailty is common in people with cardiovascular disease. Worse left atrial (LA) function is an independent risk factor for cardiovascular disease. However, whether worse LA function is associated with frailty is unclear. METHODS: We included 3292 older adults from the Atherosclerosis Risk in Communities study who were non-frail at baseline (visit 5, 2011-2013) and had LA function (reservoir, conduit, and contractile strain) measured from two-dimensional speckle-tracking echocardiography. LA stiffness index was calculated as a ratio of E/e' to LA reservoir strain. Frailty was defined using the validated Fried frailty phenotype. Incident frailty was assessed between 2016 and 2019 during two follow-up visits. LA function was analyzed as quintiles. Multivariable logistic regression examined odds of incident frailty. RESULTS: Median (interquartile range [IQR]) age was 74 (71-77) years, 58% were female, and 214 (7%) participants developed frailty during a median (IQR) follow-up of 6.3 (5.6-6.8) years. After adjusting for baseline confounders and incident cardiovascular events during follow-up, the odds of developing frailty was 2.42 (1.26-4.66) times greater among participants in the lowest (vs highest) quintile of LA reservoir strain and 2.41 (1.11-5.22) times greater among those in the highest (vs lowest) quintile of LA stiffness index. Worse LA function was significantly associated with the development of exhaustion, but not the other components of the Fried frailty phenotype. CONCLUSIONS: Worse LA function is associated with higher incidence of frailty and exhaustion component independent of LA size and left ventricular function. Future studies are needed to elucidate the underlying mechanisms that drive the observed association.

[Determining the risk of maladaptation using an electroencephalogram to prevent mental strain]. / Opredelenie riska dezadaptatsii po elektroentsefalogramme dlya preduprezhdeniya psikhicheskogo perenapryazheniya.

OBJECTIVE: To identify criteria for electroencephalogram (EEG) synchronization in patients with post-traumatic stress disorder (PTSD) exhibiting high levels of functional stress and signs of maladaptation. MATERIAL AND METHODS: Two groups of male subjects aged 23-38 years were examined: a group of subjects receiving therapy for PTSD at a medical center; and a group of healthy subjects who regularly practiced psychophysical relaxation sessions. EEG, an innovative method for analyzing brain synchronizing currents, and the Spielberger State-Trait Anxiety Inventory were used. RESULTS: Criteria for the formation of patterns of synchronization of neural networks were found in subjects of the therapy group, who have a high level of psychofunctional stress and signs of maladaptation against the background of PTSD in combination with severe anxiety and impaired cognitive abilities. CONCLUSION: Alpha wave synchronization analysis can be used to more accurately diagnose the level of psychofunctional stress in individuals at risk of developing psychophysical disorders. The results of the work suggest the use of technologies that increase the ability to synchronize brain biocurrents to develop programs for correcting psychophysical status, such as relaxation exercises.

Evolution and mutational landscape of highly pathogenic avian influenza strain A(H5N1) in the current outbreak in the USA and global landscape.

The emergence of highly pathogenic avian influenza strain A (H5N1) in the USA is a high concern. Here, we illustrated the evolution, divergence, transmission pattern, infection pattern, entropy diversity, nucleotide diversity, and mutational landscape of HPAI(H5N1). We depicted three phylogenetic trees, i.e., from three perspectives: considering the HPAI H5N1 genome of the current outbreak in the USA (n = 971), considering the HPAI H5N1 spared in different hosts (cattle, hunan, avian, and nonhuman primates) and using the global genome sequences (n = 3154). We found that the clade 2.3.4.4b was responsible for the present infection. We noted that the USA's divergence rate is 3.43e-3 subs per site per year, and the global divergence rate is 5.21e-3 subs per site per year. We reported significant nucleotide changes to illustrate the genome. Similarly, we observe several point mutations in some proteins, such as PB2, PA, HA, NA, and NS1. Among point mutations, some common mutations are noted in PB2 (E362G, M631L) and PA (L219I, K497R). However, elimination strategies should be a high priority for dairy farm workers, domestic cattle, and poultry birds to limit future outbreaks.

Utility of Magnetocardiography and Stress Speckle Tracking in Detection of Coronary Artery Disease.

Introduction: Coronary artery disease (CAD) is a leading cause of death and disability in developed countries. While exercise testing is recommended for diagnosing stable angina pectoris, its limited sensitivity and specificity have been questioned. Myocardial strain is a promising predictor of significant CAD. Aim: To evaluate the utility of myocardial strain obtained by 2D speckle tracking at rest and under stress combined with stress magnetocardiography for detecting CAD in patients with stable or low-risk unstable angina pectoris. Methods: A total of 108 patients meeting the inclusion criteria underwent coronary angiography within 48 h of admission. Myocardial strain was assessed using 2D speckle tracking at rest and during dobutamine stress alongside stress magnetocardiography. Results: Global longitudinal strain at stress showed a moderate correlation with significant CAD (r = 0.41, p <0.0001) and with coronary occlusion severity (r = 0.62, p <0.0001). Strain at stress had a sensitivity of 74.1% and specificity of 76.7% for detecting CAD at a cut-off value of -19.1. The ST fluctuation rate from magnetocardiography demonstrated the highest sensitivity for CAD detection. Conclusions: Longitudinal strain parameters and stress magnetocardiography are effective non-invasive methods for predicting CAD in patients with stable angina, potentially reducing the need for invasive assessments.

Investigation of dynamic responses of skin simulant against fragment impact through experiments and concurrent computational modeling.

Perforation of the skin by fragment impact is a key determinant of the severity of an injury and incapacitation during modern asymmetric warfare. Computational models validated against experimental data are thus desired for simulating the responses of a skin simulant against fragment impact. Toward this end, experiments and concurrent computational modeling were used to investigate the dynamic responses of the skin simulant against fragment impact. Fragment simulating projectiles (FSPs) of masses 1.10 g and 2.79 g were considered herein, and the responses of the skin simulant were investigated in terms of the threshold velocity, energy density, peak displacement, and failure mechanisms. The results illustrate numerous salient aspects. The skin simulant failure involved cavity shearing followed by elastic hole enlargement, and these results were sensitive to the strain rate. The best agreement between the simulated and experimental results was achieved when the input stress-strain curves to the simulation were based on the full spectrum of strain rates. When a single stress-strain curve corresponding to a specific strain rate was used as the input, the threshold velocity and peak displacement of the skin simulant were either underpredicted or overpredicted depending on the strain rate considered. The threshold velocity was also sensitive to the input failure strain; here, the best agreement was obtained when the failure strain was based on the theoretical limiting strain. When the FSP materials were changed to plastics, the threshold velocities increased by up to 33%; however, the energy densities and generated stresses exceeded the contusion and laceration thresholds of the skin.

The influence of selected grain size fractions of coal fly ash on properties of clay-cement mortars used for the flood levees construction.

This study examines the influence of different grain size fractions of coal fly ash on the properties of clay-cement mortars used in flood levee construction. Dry aerodynamic separation and mesh sieving were used to obtain ultrafine, fine, and medium fractions of high-calcium and silica fly ash. The experimental results reveal that the rheological properties of fresh mortars are significantly influenced by these fractions. High-calcium fly ash mortars exhibit high reactivity and rapid increase in viscosity, with finer fractions showing the highest reactivity. Silica ashes show increased reactivity in the later stages of suspension hardening. Their spherical shape contributes to reducing internal friction during flow in initial technological operations. Furthermore, the compressive strength of hardened mortars improves as the particle size decreases for both ashes, resulting in a dense and uniform microstructure. The separation and fractionation of fly ashes contribute to the obtaining of fractions that influence the parameters of clay-cement suspension application on different scales. The results show the potential benefits of ash separation, which can bring advantages in terms of economic viability, engineering performance, and ecological sustainability.

Experimental and numerical investigation of waterjet interaction with liver in connection with surgical technique.

Hepatectomy, or liver resection, is a process by which through surgery part or all of the liver is removed. In this operation, less bleeding, negligible damage and fast removal are the most important requirements. Surgery through waterjet is one of the most efficient techniques which is widely used in hepatectomy. Some clinical studies are conducted to investigate waterjet method in liver resection. In the present study interaction of waterjet with liver during the process of the surgery is investigated in terms of mechanical engineering. For this purpose, a system of waterjet is designed to consider the interaction of waterjet with liver at different nozzle diameter and velocities. For validation, SPH-FEM model is used to analyze waterjet interaction with hyperelastic liver. In this model, liver cutting is simulated using element deletion defined by a subroutine code based on maximum principal strain criterion. Depth of cut along with degraded volume are measured experimentally and compared with simulated method. Results show that good agreement exists between experimental and simulation finding. By comparing depth of cut in the experimental and simulation results, it can be seen that liver behavior changes from brittle to ductile by increasing waterjet velocity during the experimental tests. For the simulation, maximum principal strain threshold is set to be between 0.1 and 0.4. However, the best agreement between experimental and simulation results exists at maximum principal strain threshold equal to 0.2. The findings can help surgeons to find the best working range of waterjet device and the most efficient operation.

Chronic mastitis manifest as complex breast cyst in ultrasound and the role of elastography: A case series.

This case series aims to describe the clinical presentation of mastitis, the conventional sonography and elastography findings, and histopathological features in the diagnosis of chronic mastitis. We present 3 cases of breast swelling in young ladies with one of the cases is related to breastfeeding with similar imaging appearance of complex breast cyst and the histopathology finding of chronic mastitis. We will describe the role of elastography in evaluating and differentiating the benign and malignant complex breast cyst.