Fractional Volume Change Research Articles

Analysis of high temperature phase transformation behavior of ultra-low-carbon steel using X-ray topography, diffraction, and synchronized temperature measurement

Despite the technical importance of δ/γ phase transition in steel alloys, conventional thermal analysis techniques like calorimetry lack precise kinetics measurement. This study introduces an integrated approach combining X-ray topographic imaging, diffraction, and precise temperature measurement to overcome these limitations. This methodology allows for the accurate quantification of recalescence due to release of latent heats from solidification and solid-state phase transformation. It also enables tracking of the fractional volume changes of the δ phase during continuous cooling. We demonstrate that in Ultra-Low Carbon steels, the δ to γ transformation occurs rapidly in the single γ phase region far below the solidus temperature in the phase diagram, and this transformation accelerates further in the higher cooling rate. Furthermore, it can be inferred that in phase transformation, its rate becomes a critical factor in the temperature increase resulting from the released latent heat, overshadowing the influence of undercooling during continuous cooling.

High ejection fraction of the left ventricular trabecular layer of the human heart

AbstractNumerous diagnostic criteria for excessive trabeculation, or “noncompaction,” score the extent of the trabecular layer. Whether the trabeculations themselves have a poor or good contractility is largely unknown. We retrospectively analyzed cardiac magnetic resonance (CMR) of patients with excessive trabeculation of the left ventricle (LV). The LV was labeled into four regions: compact wall, central cavity (CC), trabeculations, and intertrabecular recesses (IR). For each label we calculated the systolic fractional volume change (SFVC) in short‐axis images (n = 15) and systolic fractional area change (SFAC) in four‐chamber images (n = 30). We measured the ejection fraction (EF) of IR, CC, and total cavity. Three methods to calculate EF of the total cavity were compared: trabeculations included (per guidelines), IR excluded (Jacquier criterion), and trabeculations contoured and excluded (contour‐EF). The SFVC and SFAC of the compact wall were similar with SFVC and SFAC of trabeculations. In contrast, the IR were more diminished in systole by comparison with the CC, having lower SFVC (39% vs. 56%) and SFAC (37% vs. 72%). EF of the IR was also greater than EF of the CC (61% vs. 44%). Excluding IR from the total cavity or including trabeculations negatively impacts the EF (44% and 40%, respectively, vs. 51% for contour‐EF). The trabecular layer operates at a high EF.

Effects of Renin–Angiotensin Blockade on the Components of Early Interstitial Expansion in Patients with Type 1 Diabetes

Interstitial expansion is associated with glomerular filtration rate (GFR) loss in many renal diseases, including diabetic nephropathy. The Renin–Angiotensin System Study (RASS) tested whether a 5-year renin–angiotensin system (RAS) blockade with enalapril or losartan versus placebo slowed progression of early diabetic nephropathy lesions in 285 normoalbuminuric, normotensive, normal/high GFR patients with type 1 diabetes. RASS found no benefit to the RAS blockade on diabetic glomerular lesions but observed an unexpected 50% increase in the fractional volume of the renal cortex which is the interstitium. The effects of the RAS blockade on individual interstitial components––striated collagen, interstitial cells, and peritubular capillaries––were not assessed. We evaluated by electron microscopy changes in fractional volume of each component in seven patients from each group between baseline and five years. At baseline, 49% of the interstitium was collagen, 12% cells, 26% peritubular capillaries, 7% space, and 2% artifact. There was no overall change in the interstitial composition during the RASS. There were no statistically significant effects of treatment group on any interstitial components. Renal volume remained stable in all groups. The RAS blockade affected neither the approximately 50% increase in interstitium fractional volume per cortex nor the parallel increase in all interstitial components that occurred over the five years of the RASS.

New Correlation for Predicting Undersaturated Oil Compressibility for Mishrif Reservoir in the Southern Iraqi Oil Fields

Reservoir fluids properties are very important in reservoir engineering computations such as material balance calculations, well testing analyses, reserve estimates, and numerical reservoir simulations. Isothermal oil compressibility is required in fluid flow problems, extension of fluid properties from values at the bubble point pressure to higher pressures of interest and in material balance calculations (Ramey, Spivey, and McCain). Isothermal oil compressibility is a measure of the fractional change in volume as pressure is changed at constant temperature (McCain). The most accurate method for determining the Isothermal oil compressibility is a laboratory PVT analysis; however, the evaluation of exploratory wells often require an estimate of the fluid behavior prior to obtaining a representative reservoir sample. Also, experimental data is often unavailable.Empirical correlations are often used for these purposes.This paper developed a new mathematical model for calculating undersaturated oil compressibility using 129 experimentally obtained data points from the PVT analyses of 52 bottom hole fluid samples from Mishrif reservoirs in the southern Iraqi oil fields. The new undersaturated oil compressibility correlation developed using Statistical Analysis System (SAS) by applying nonlinear multiple regression method. It was found that the new correlation estimates undersaturated oil compressibility of Mishrif reservoir crudes in the southern Iraqi oil fields much better than the published ones. The average absolute relative error for the developed correlation is 7.16%.

Highly accelerated dynamic acquisition of 3D grid-tagged hyperpolarized-gas lung images using compressed sensing.

To develop and test compressed sensing-based multiframe 3D MRI of grid-tagged hyperpolarized gas in the lung. Applying grid-tagging RF pulses to inhaled hyperpolarized gas results in images in which signal intensity is predictably and sparsely distributed. In the present work, this phenomenon was used to produce a sampling pattern in which k-space is undersampled by a factor of approximately seven, yet regions of high k-space energy remain densely sampled. Three healthy subjects received multiframe 3D 3 He tagging MRI using this undersampling method. Images were collected during a single exhalation at eight timepoints spanning the breathing cycle from end-of-inhalation to end-of-exhalation. Grid-tagged images were used to generate 3D displacement maps of the lung during exhalation, and time-resolved maps of principal strains and fractional volume change were generated from these displacement maps using finite-element analysis. Tags remained clearly resolvable for 4-6 timepoints (5-8s) in each subject. Displacement maps revealed noteworthy temporal and spatial nonlinearities in lung motion during exhalation. Compressive normal strains occurred along all three principal directions but were primarily oriented in the head-foot direction. Fractional volume changes displayed clear bilateral symmetry, but with the lower lobes displaying slightly higher change than the upper lobes in 2 of the 3 subjects. We developed a compressed sensing-based method for multiframe 3D MRI of grid-tagged hyperpolarized gas in the lung during exhalation. This method successfully overcomes previous challenges for 3D dynamic grid-tagging, allowing time-resolved biomechanical readouts of lung function to be generated.

Phase transitions in high-purity zirconium under dynamic compression

We present results from ramp compression experiments on high-purity Zr that show the $\ensuremath{\alpha}\ensuremath{\rightarrow}\ensuremath{\omega}, \ensuremath{\omega}\ensuremath{\rightarrow}\ensuremath{\beta}$, as well as reverse $\ensuremath{\beta}\ensuremath{\rightarrow}\ensuremath{\omega}$ phase transitions. Simulations with a multiphase equation of state and phenomenological kinetic model match the experimental wave profiles well. While the dynamic $\ensuremath{\alpha}\ensuremath{\rightarrow}\ensuremath{\omega}$ transition occurs $\ensuremath{\sim}9\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$ above the equilibrium phase boundary, the $\ensuremath{\omega}\ensuremath{\rightarrow}\ensuremath{\beta}$ transition occurs within 0.9 GPa of equilibrium. We estimate that the dynamic compression path intersects the equilibrium $\ensuremath{\omega}\text{\ensuremath{-}}\ensuremath{\beta}$ line at $P=29.2\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$, and $T=490\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. The thermodynamic path in the interior of the sample lies $\ensuremath{\sim}100\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ above the isentrope at the point of the $\ensuremath{\omega}\ensuremath{\rightarrow}\ensuremath{\beta}$ transition. Approximately half of this dissipative temperature rise is due to plastic work, and half is due to the nonequilibrium $\ensuremath{\alpha}\ensuremath{\rightarrow}\ensuremath{\omega}$ transition. The inferred rate of the $\ensuremath{\alpha}\ensuremath{\rightarrow}\ensuremath{\omega}$ transition is several orders of magnitude higher than that measured in dynamic diamond anvil cell (DDAC) experiments in an overlapping pressure range. We discuss a model for the influence of shear stress on the nucleation rate. We find that the shear stress ${s}_{ji}$ has the same effect on the nucleation rate as a pressure increase $\ensuremath{\delta}P=c{\ensuremath{\epsilon}}_{ij}{s}_{ji}/(\mathrm{\ensuremath{\Delta}}V/V),$ where $c$ is a geometric constant $\ensuremath{\sim}1$ and ${\ensuremath{\epsilon}}_{ij}$ are the transformation shear strains. The small fractional volume change $\mathrm{\ensuremath{\Delta}}V/V\ensuremath{\approx}0.1$ at the $\ensuremath{\alpha}\ensuremath{\rightarrow}\ensuremath{\omega}$ transition amplifies the effect of shear stress, and we estimate that for this case $\ensuremath{\delta}P$ is in the range of several GPa. Correcting our transition rate to a hydrostatic rate brings it approximately into line with the DDAC results, suggesting that shear stress plays a significant role in the transformation rate.

Interferometric SAR modelling of near surface data to improve geological model in the Surat Basin, Australia

This paper presents a study on geophysical inverse modelling for subsurface structural properties of an unconventional hydrocarbon site that was monitored previously by Interferometric Synthetic Aperture Radar (InSAR) technology for surface deformation. A static three-dimensional geomodel along with extracted property maps replicates the depth of each underlying stratigraphic unit and structural feature with the density of each geological layer. We examine the hypothesis that integration of elastic properties of each formation layer with InSAR observations in a stratified elastic medium will lead to a viscoelastic geophysical inverse problem that can be solved to estimate fractional volume change at the reservoir level. Moreover, we examine synthetic scenarios in which the elastic properties of the formations are perturbed before determining the resulting impact on the rate of surface deformation. The results show that although the slope of underlying formations, their density and depth can define the extent and pattern of a deformation signal, their properties have a marginal impact on volumetric change compared to the dense network of shallow depth Coal Seam Gas (CSG) mining wells. Besides, it is also demonstrated that the inversion of InSAR deformation maps can resolve the uncertainties associated with low-resolution seismic interpretation as well as filling the data gaps within seismic acquisitions. A significant contribution of this investigation to the geological basin modelling involves a) introducing a remote and non-invasive technology such as InSAR to improve geophysical mapping of subsurface structures such as faults in areas with sparse or no reflective seismic information, and b) applying a multi-layer viscoelastic geophysical source model for an unconventional hydrocarbon reservoir such as CSG.

Comparing Growth Rates of Simulated Moist and Dry Convective Thermals

AbstractThe spreading rates of convective thermals are linked to their net entrainment, and previous literature has suggested differences in spreading rates between moist and dry thermals. In this study, growth rates of idealized numerically simulated axisymmetric dry and moist convective thermals are directly compared. In an environment with dry-neutral stratification, the increase of thermal radius with height dR/dz is a larger by a factor of 1.7 for dry thermals relative to moist thermals. The fractional change in thermal volume ε is also greater for dry thermals within a distance of ~4 radii from the initial thermal height. Values of dR/dz are nearly constant with height for both moist and dry thermals consistent with classical theory based on dimensional analysis. The simulations are also consistent with theory relating impulse, circulation, and spreading rate for dry thermals proposed in previous papers and extended here to moist thermals, predicting they will spread less than dry thermals. Tests adding heating to dry thermals, either spread uniformly across the thermal volume or concentrated in the inner core, indicate that dR/dz and ε are smaller for moist thermals because latent heating is confined mostly to their cores. Additional axisymmetric moist simulations using modified lapse rates and large-eddy simulations support this analysis. Overall, these results indicate that slow spreading rates are a fundamental feature of moist thermals caused by latent heating that alters the spatial distribution of buoyancy within them relative to dry thermals.

Mathematical Modeling of Reversible Bimolecular Catalyzed Transesterification Reaction Kinetics for PKO and Methanol synthesis

Continuous appraisal for alternative renewable energy sources particularly for bio-diesel production is a great concern to engineers and scientist globally. Actually, vegetable oils and C1 to C3 alcohol group alkali catalyzed transesterification reaction leads to bio-diesel production. The aspect of developing reaction time and disappearance rate (-RA) mathematical models for effective various reactor types design seems impassive. Hence, in this work the authors developed a unified reaction time and disappearance rate (-RA) predictive models as a function of reactants and product reaction rate constants (K1 K2), molar masses (MW), conversion (XA), fractional volume change (ɛ) and density (ρ) dimensions using partial fraction and by parts integration methods. The developed models were simulated with Matlab codes programming approach exploiting the kinetics parameters of PKO , Methanol and biodiesel. The results of the reaction time (t) at equilibrium, none equilibrium and disappearance rate (-RɛA) show dependable relationship with the stipulated dimensions and were quite compatible with those of inferential laboratory physicochemical data reported. Thus;

Simplified Rate Expression for Palm Kernel Oil (PKO) and Methanol Alkali Catalyzed Transesterification Reaction

The need for the development of simplified kinetics rates expression (-RA) for Vegetable Oils Alkali catalyzed Transesterification processes to enhance biodiesel production motivated this study. The study, therefore aimed at proposing unified simple rate expression that may be a useful prelude to design various reactor types for Alkali Catalyzed Transesterification of palm kernel oil (PKO) and Methanol reactions. The kinetics rate expression is proposed using simple explicit algebraic technique with the consideration that alkali catalyzed transesterification reaction of palm kernel oil and methanol is a reversible bimolecular reaction. The proposed kinetic reaction rate expression is developed as a function of conversion (XA), reactants and products concentration and reaction rate constants (k1 and k2). The kinetics reaction rate expression obtained is further evaluated on the basis of reactants and product molar masses and densities. The developed models were simulated using Matlab codes programming techniques. The results for kinetic reaction rates (-RA & -ReA) decreases with decrease in fractional volume change (e) and increase in fractional conversion at constant reaction time. The results were quite compatible with those of inferential laboratory physicochemical characterization reported.

Simplified Rate Expression for Palm Kernel Oil (PKO) and Methanol Alkali Catalyzed Transesterification Reaction

The need for the development of simplified kinetics rates expression (-RA) for Vegetable Oils Alkali catalyzed Transesterification processes to enhance biodiesel production motivated this study. The study, therefore aimed at proposing unified simple rate expression that may be a useful prelude to design various reactor types for Alkali Catalyzed Transesterification of palm kernel oil (PKO) and Methanol reactions. The kinetics rate expression is proposed using simple explicit algebraic technique with the consideration that alkali catalyzed transesterification reaction of palm kernel oil and methanol is a reversible bimolecular reaction. The proposed kinetic reaction rate expression is developed as a function of conversion (XA), reactants and products concentration and reaction rate constants (k1 and k2). The kinetics reaction rate expression obtained is further evaluated on the basis of reactants and product molar masses and densities. The developed models were simulated using Matlab codes programming techniques. The results for kinetic reaction rates (-RA & -ReA) decreases with decrease in fractional volume change (e) and increase in fractional conversion at constant reaction time. The results were quite compatible with those of inferential laboratory physicochemical characterization reported.

Differences in fetal fractional limb volume changes in normal and gestational diabetic pregnancies: an exploratory observational study.

Fetal fractional limb volume has been proposed as a useful measure for quantifying fetal soft tissue development. The aim of this study was to investigate the growth of fractional arm volume (AVol) and fractional thigh volume (TVol) of fetuses with maternal gestational diabetes (GDM) compared with those of fetuses with normal glucose tolerance (NGT). We hypothesised fetal fractional limb volume would be larger in the GDM group than in the NGT group in late gestation. Exploratory observational study. Saitama Municipal Hospital. A total of 165 (125 NGT and 40 GDM) singleton Japanese pregnant women. AVol and TVol were assessed between 20 and 37weeks' gestation as cylindrical limb volumes based on 50% of the fetal humeral or femoral diaphysis length. Women were diagnosed as GDM based on the criteria of the Japan Society of Obstetrics and Gynecology. AVol and TVol were compared between women with NGT and those with GDM at each gestational age period (2-week intervals from 20 to 37weeks' gestation). Overall, 287 ultrasound scans were performed (NGT group, 205 scans; GDM group, 82 scans). There was no significant difference of AVol between the groups before 32weeks' gestation. AVol was significantly larger in the GDM group than in the NGT group after 32weeks' gestation (P<0.05). TVol was not statistically different between the groups across gestation. Detection of variations in fetal AVol may provide greater insight into understanding the origins of altered fetal body proportion in GDM. AVol, but not TVol, is significantly larger in fetuses with GDM than in those with NGT after 32weeks' gestation.

The Repeatability and Left Atrial Strain Analysis Obtained via Speckle Tracking Echocardiography in healthy Dogs

IntroductionIn left atrial (LA) strain–derived two-dimensional speckle tracking echocardiography, the reference intervals in healthy dogs can provide useful information to evaluate the LA function in dogs with heart disease. AnimalsSix laboratory beagles and 120 privately owned dogs without cardiac diseases were recruited. Materials and methodsThe LA strain and strain rate (SR) and echocardiographic indices were obtained in dogs who underwent standard echocardiography and offline analysis for LA strain and SR measurement by speckle tracking echocardiography. ResultsThe intra-observer within-day variations of strain variables showed adequate repeatability (coefficient of variation <20%). The mean values of strain were 25.37 for the LA reservoir function, 11.06 for the LA conduit function, and 14.17 for the LA booster-pump function; the strain was significantly correlated with the LA fractional volume change at each phasic function. The left atrial longitudinal strain during early ventricular diastole showed moderate correlation with the peak velocity of early diastolic transmitral flow (r = 0.5560) and ratio of peak velocity of early diastolic transmitral flow to peak velocity of late transmitral flow (r = 0.5515).In multiple regression analysis, only age was significantly related to the strain/SR and volumetric change indices, indicating conduit function. ConclusionsLeft atrial speckle tracking echocardiographic analysis provided useful information to assess the LA function in healthy dogs. The influencing factors on strain and SR variables including the age, body weight, and heart rate should be considered in interpretation of these parameters in a clinical setting.

Right ventricular free wall stress after tricuspid valve annuloplasty in acute ovine right heart failure

BackgroundTricuspid annuloplasty rings may have a direct impact on right ventricular shape and free wall stress, potentially affecting chamber remodeling and recurrent regurgitation. In an acute model of ovine right heart failure, we investigated right ventricular free wall stress after annuloplasty with different prostheses. MethodsThirty-xix sheep underwent implantation of sonomicrometry crystals on the tricuspid annulus and right ventricle. Each group consisted of 9 animals that received a flexible (28 ± 1 mm), rigid (29 ± 1 mm), or flexible-rigid hybrid (28 ± 1 mm) ring. Nine control animals had no ring implanted. Hemodynamic, sonomicrometry, and echocardiographic data were collected before (baseline-control group) and during acute right heart failure (control and ring groups). Free wall stress was calculated using the modified Laplace formula for thick shells. Ventricular geometry was determined from 3-dimensional crystal coordinates. ResultsAcute right heart failure reduced right ventricular deformation and fractional volume change while increasing pressure, tricuspid regurgitation grade, cross-sectional area, and free wall stress in control animals versus baseline. All rings significantly decreased right ventricular free wall stress versus control except rigid ring at end-systole. There was no significant difference in free wall stress or tricuspid regurgitation between any ring group during acute heart failure and baseline-control group. No significant difference in free wall stress was observed between any of the ring groups. ConclusionsAcute right heart failure significantly increased right ventricular free wall stress, which was normalized with equal efficacy by all studied prostheses. Chronic studies are needed to evaluate long-term effects of annuloplasty rings on right ventricle free wall stress and remodeling.

In-human subject-specific evaluation of a control-theoretic plasma volume regulation model

The goal of this study was to conduct a subject-specific evaluation of a control-theoretic plasma volume regulation model in humans. We employed a set of clinical data collected from nine human subjects receiving fluid bolus with and without co-administration of an inotrope agent, including fluid infusion rate, plasma volume, and urine output. Once fitted to the data associated with each subject, the model accurately reproduced the fractional plasma volume change responses in all subjects: the error between actual versus model-reproduced fractional plasma volume change responses was only 1.4 ± 1.6% and 1.2 ± 0.3% of the average fractional plasma volume change responses in the absence and presence of inotrope co-administration. In addition, the model parameters determined by the subject-specific fitting assumed physiologically plausible values: (i) initial plasma volume was estimated to be 36 ± 11 mL/kg and 37 ± 10 mL/kg in the absence and presence of inotrope infusion, respectively, which was comparable to its actual counterpart of 37 ± 4 mL/kg and 43 ± 6 mL/kg; (ii) volume distribution ratio, specifying the ratio with which the inputted fluid is distributed in the intra- and extra-vascular spaces, was estimated to be 3.5 ± 2.4 and 1.9 ± 0.5 in the absence and presence of inotrope infusion, respectively, which accorded with the experimental observation that inotrope could enhance plasma volume expansion in response to fluid infusion. We concluded that the model was equipped with the ability to reproduce plasma volume response to fluid infusion in humans with physiologically plausible model parameters, and its validity may persist even under co-administration of inotropic agents.

On the search of rigorous thermo-kinetic model for wet phase inversion technique

Polymeric membranes are usually fabricated by phase inversion process because the membrane morphology and its separation properties can be altered directly by the process conditions. The experimental study of this process and involved subsequent phenomenological events is almost impossible in many cases, mainly due to the fast rates of solvent/nonsolvent exchange and small thickness of cast polymeric film. Hence, many researchers have mathematically tried to develop predictive models. However, to establish a predictive model, an appropriate coupling of thermodynamic stability states of polymeric solution and the different possible involved kinetic mechanisms must be incorporated as investigated in the present work. Here, first, it has been shown that previous models had incorporated incorrect assumptions during model development and inconsistent form of governing equations for numerical calculations has been used which violates the conservative characteristics of mass conservation laws. The governing equations were obtained and used in simulations. In addition, interpretation of interface between the dope phase and coagulation phase was implemented using a kinetic approach instead of local pseudo thermodynamic phase equilibria. The compressible regular solution model was used for calculations of thermodynamic properties as well as construction of phase diagrams and boundaries. The equation of changes in thickness of cast film was established by using the fractional volume changes upon mixing allowing the assessment of cast film geometry effect on the process dynamics directly. Also, the mass average velocity equation was corrected and new expression was obtained. As case study, the cellulose acetate/acetone/water ternary system was used for evaluation of the developed model. The developed thermo-kinetic model was successful in prediction of membranes properties/morphology as compared to the available data. It has been shown that the practical precipitation path is different to those of reported in literature except for the regions near the interface as this skin layer reaches to its final stable condition in early moments of immersion process. The results are presented and discussed in details.

Magnetic resonance Imaging (MRI), liquid biopsies, and patient derived organoids (PDOs) as biomarkers of response to regorafenib (REG) in treatment-refractory metastatic colorectal cancer (mCRC) patients (pts).

613 Background: REG demonstrated efficacy in pre-treated mCRC pts. Lack of predictive biomarkers, potential toxicities and cost/effectiveness concerns highlight the unmet need for better patient selection. Methods: RAS mutant mCRC pts with biopsiable metastases were enrolled in this phase II trial. Tissue biopsies (6-12 cores) were obtained at baseline (BL), after 2 months if stable disease (SD) and at disease progression (PD). Dynamic contrast enhanced (DCE) MRI was acquired pre and at day 15 post-treatment. Median values of volume transfer constant (Ktrans) and enhancing fraction (EF) [K-trans*EF/100] were generated. Circulating tumour (ct)DNA was collected monthly until PD and tested for clonal RAS mutations by digital droplet PCR. PDOs derived from responders and non-responders pts were implanted orthotopically in the liver of mice and treated with REG for 5 days. Changes in tumour and fractional blood volume (fBV) were monitored by oxygen-enhanced MRI. Results: mCRC pts (n = 27) with paired MRI scans were analysed; a single target lesion per pt was chosen (25 liver and 2 pelvic metastases). Median K-trans*EF/100 product decrease was 58.2%. In the 23 analysable pts (4 received &lt; 1 cycle of treatment due to toxicities), &gt; 70% drop in K-trans*EF/100 (8/23) was associated with higher disease control rate (6/6 vs. 0/6, p = 0.048) measured by RECIST 1.1 at 2 months, improved progression free survival (PFS) [HR = 0.24 (0.07-0.86), p = 0.03], and 4-month PFS (58.3% VS 21.2%). Sequential tissue biopsies analysis confirmed reduction in CD31 in pts with K-trans*EF/100 drop. RAS mutant clones decay in ctDNA after 8 weeks of treatment was associated with better PFS [HR = 0.25 (0.08 - 0.83), p = 0.02] independently of K-trans*EF/100 drop. PDOs xeno-transplants treated with REG compared to controls had significant lower tumour fBV (4.5 VS 10.6, p = 0.03) and lower microvascular density measured by CD31 staining (4.3 VS 8.9, p = 0.02). Conclusions: Combining DCE MRI and ctDNA predicts depth and duration of anti-angiogenic response to REG monotherapy and may improve pt selection with potential health/economic implications. Clinical trial information: 201400357951.

Transient left atrial dysfunction is a feature of Takotsubo syndrome

BackgroundTakotsubo syndrome (TTS) is characterized by a transient left and/or right ventricular dysfunction as a consequence of a distinctive pattern of regional wall motion abnormalities. However, a systematic evaluation of the left atrial (LA) function in patients with TTS is lacking. The aim of the present study was therefore to comprehensively assess LA performance indexes and function in patients with TTS.MethodsWe compared LA function assessed by volumetric indexes derived from fractional volume changes in cardiovascular magnetic resonance (CMR) between 125 TTS patients and 125 patients with anterior ST-segment elevation myocardial infarction (STEMI). Furthermore, recovery of LA performance was evaluated in a subgroup of 20 TTS patients with follow-up CMR data.ResultsPatients with TTS demonstrated a significantly lower total LA emptying fraction (EF) [44% (interquartile range (IQR) 34–53%) versus 51% (IQR 42–56%); p < 0.01], passive LA-EF [21% (IQR 14–30%) versus 24% (IQR 20–29%); p = 0.03] and active LA-EF [29% (IQR 20–38%) versus 35% (28–42%); p < 0.01] compared to patients with anterior STEMI. Among the 20 TTS patients with serial CMR data, the total LA-EF significantly improved from 42% (IQR 29–48%) at the acute stage to 51% (IQR 46–59%) at follow-up (p < 0.01). Similarly, active LA-EF (p < 0.01) and passive LA-EF (p = 0.02) improved significantly as well.ConclusionCompared to anterior STEMI, TTS patients demonstrated a significantly decreased LA function during the acute/subacute phase of the disease. However, impairment of LA performance seems to be transient in TTS with recovery during follow-up.

Left Atrial Performance in the Course of Hypertrophic Cardiomyopathy: Relation to Left Ventricular Hypertrophy and Fibrosis.

Hypertrophic cardiomyopathy (HCM) is associated with left atrial (LA) functional abnormalities. The determinants and the degree of LA dysfunction in the course of HCM are not fully understood. We aimed to characterize LA mechanics in HCM, according to the extent of left ventricular (LV) hypertrophy and fibrosis. Seventy-three HCM patients and 23 age- and sex-matched controls underwent cardiovascular magnetic resonance imaging including late gadolinium enhancement (LGE). LA reservoir, conduit, and contractile functions were quantified by fractional volume changes and cardiovascular magnetic resonance feature-tracking-derived strain and strain rate. In multivariable regression, LA mechanics were associated with the extent of LV LGE (P = 0.033 to P < 0.001), but not with the LV mass extent or maximum wall thickness (P = 0.108 to P = 0.964). Left atrial function decreased according to the increase in extent of LV fibrosis (non-LGE; mild LGE ≤ 10%; intermediate LGE 11%-19%; severe LGE ≥ 20%). Compared with healthy controls, LA conduit function was impaired in HCM with no LGE already (LA emptying fraction conduit: 32% ± 7% vs 26 ± 14, P = 0.037). Conversely, LA contractile booster pump function was impaired in HCM with severe LGE only (LA emptying fraction booster: 40% ± 8% vs 20% ± 10%, P < 0.001; for controls vs LGE ≥ 20%, respectively). Left atrial functional abnormalities are associated with LV fibrosis, but not with LV hypertrophy. While LA conduit function is impaired in early HCM stages as represented by mild or absent LV fibrosis, LA contractile function is impaired later in the course of disease progression as demonstrated by the presence of severe LV fibrosis only. These novel markers of LA performance may potentially proof useful for disease staging and early detection of cardiac deterioration.

Dynamic Evaluation of Lavage Efficacy in Upper Compartment of the Temporomandibular Joint

The aim of this study was to determine the most efficient temporomandibular joint (TMJ) lavage technique for complete irrigation and removal of synovial fluid. The corresponding total lavage fluid volume needed also was investigated. Three-dimensional TMJ lavage models of the classic double- and single-needle techniques with modified cannula sizes (diameters, 2.4 and 0.8mm) were generated based on a constructed upper compartment model. Models were integrated with 2-phase flow models to predict fractional fluid volume (α value) changes of lavage saline and synovial fluid within the upper compartment of the TMJ. Fluid flow diagrams, velocity vectors, and intra-articular pressure data were collected and compared among the models. Models were validated by clinical synovial fluid concentration analyses, with vitamin B12 used as an internal standard. In all 8 models, lavage fluid initially gathered around the inflow portal, with a stable mixture of synovial and lavage fluids eventually being established in the compartment. Use of the double-needle technique with a large inflow portal resulted in thorough lavage (α= 100%). When the single-needle or Shepard cannula technique was used, some areas within the upper compartment remained devoid of brisk flow. The 2.4-mm inflow model coupled with a 0.8-mm outflow portal resulted in a stably and persistently high intra-articular pressure (>2.7 × 104Pa). A minimum volume of 109mL of lavage fluid was necessary for complete replacement of synovial fluid by saline. When a 2.4-mm inflow portal needle was applied, a lavage rate of 100% was obtained with a minimum lavage volume of 109mL. Using a small inflow portal could lead to inadequate flow, residual synovial fluid, and, ultimately, treatment failure.