Low Relaxation Time Research Articles

Increased Tone and Stiffness of the Teres Major Muscle in Elite Handball Athletes: A Cross-Sectional Study

Background: The aim of this study was to determine whether the elite handball (HB) athletes with glenohumeral internal rotation deficit (GIRD) present differences in the mechanical properties in the teres major muscle, and strength and extensibility of the posterior shoulder tissues of the throwing shoulder (TS) compared to the non-throwing (non-TS) and non-HB athletes. Methods: A cross-sectional study was carried out, with sixty male participants: 30 HB athletes with GIRD and 30 age-matched healthy non-HB athletes. Mechanical properties of the teres major muscle were measured with MyotonPRO; also, extensibility of the posterior shoulder tissues and maximum isometric internal rotation (IR) and external rotation (ER) strength were recorded. Results: The teres major muscle of the TS in the HB group achieved a higher tone (Δ 0.34; 95% CI: 0.15, 0.53) and stiffness (Δ 30.86; 95% CI: 23.04,38.68), and a lower relaxation time compared to the non-TS of the same group (Δ −0.69; 95% CI: −1.15, −0.24;) and to the TS of the control group for the tone (Δ 0.36; 95% CI: 0.02, 0.70) and for the stiffness (Δ 27.03; 95% CI: 15.24, 38.83). The extensibility of the TS of the HB group presented a statistically significant decrease compared to the control group (Δ−7.83; 95% CI: −12.42, 3.23). A between-groups ER/IR ratio imbalance was found for the TS (Δ−12.18; 95% CI: −25.59, −1.23) and the non-TS (Δ−13.01; 95% CI: −25.79, −0.25). Conclusions: HB athletes with GIRD present a higher tone and stiffness of the teres major muscle and lack of extensibility of the tissues of the posterior part of the shoulder compared to the non-TS and to healthy non-HB athletes.

Assessment of articular cartilage of ankle joint in stable and unstable unilateral weber type-B/SER-type ankle fractures shortly after trauma using T2 relaxation time.

Early detection of post-traumatic cartilage damage in the ankle joint in magnetic resonance images can be difficult due to disturbances to structures usually appearing over time. To study the articular cartilage of unilateral Weber type-B/SER-type ankle fractures shortly post-trauma using T2 relaxation time. Fifty one fractured ankles were gathered from consecutively screened patients, compiled initially for RCT studies, and treated at Oulu University Hospital and classified as stable (n = 28) and unstable fractures (n = 23) based on external-rotation stress test: medial clear space of ≥5mm was interpreted as unstable. A control group of healthy young individuals (n = 19) was also gathered. All ankles were imaged on average 9 (range: 1 to 25) days after injury on a 3.0T MRI unit for T2 relaxation time assessment, and the cartilage was divided into sub-regions for comparison. Control group displayed significantly higher T2 values in tibial cartilage compared to stable (six out of nine regions, p-values = .003-.043) and unstable (six out of nine regions, p-values = .001-.037) ankle fractures. No differences were detected in talar cartilage. Also, no differences were observed between stable and unstable fractures in tibial or talar cartilage. Lower T2 relaxation times of tibial cartilage in fractured ankles suggest intact extra cellular matrix (ECM) of the cartilage. Severity of the ankle fracture, measured by ankle stability, does not seem to increase ECM degradation immediately after trauma.

Disulfide Bond Accelerated Transesterification in Poly(β-hydrazide disulfide esters) toward Fast Network Rearrangements.

The development of catalyst-free ester-based covalent adaptable networks (CANs) provides a new approach to achieve milder reaction conditions to reprocess thermoset resins. Despite recent advances, however, accelerating network rearrangements requires the introduction of hydroxyl groups into the network. In this study, disulfide bonds are introduced into the CANs to add new kinetically facile pathways to accelerate network rearrangement. Kinetic experiments using small molecule models of the CANs show that the presence of the disulfide bonds can accelerate transesterification. These insights are applied to synthesize new kinds of poly(β-hydrazide disulfide esters) (PSHEs) using thioctic acyl hydrazine (TAH) as a precursor for ring-opening polymerization with the hydroxyl-free multifunctional acrylates. The PSHE CANs have lower relaxation times (505-652 s) than the polymer containing only β-hydrazide esters (2903 s). The ring-opening polymerization of TAH improves the crosslinking density, heating resistance deformation temperature, and UV shielding performance of the PSHEs. Thus, this work provides a practical strategy to reduce the reprocessing temperatures of CANs.

Can Speckle Tracking Of Right Ventricle Add Value For Evaluation Of Asthma Severity In Children?

To investigate myocardial deformation by tracking speckles along with evaluation of cardiac function using conventional and tissue Doppler imaging. The case-control study was conducted at Kafrelsheikh University Hospital, Egypt, from September 2019 to May 2022, and comprised asthmatic children and healthy controls matched for age and gender. After taking family history of asthma, assessments were made for bronchial asthma treatment and severity. Clinical examination and pulmonary function tests were performed along with tissue Doppler imaging and speckle tracking. Global left ventricular and right ventricular strains were measured. Data was analysed using SPSS 22.. Of the 120 subjects, 60(50%) were cases; 33(55%) males and 27(45%) females with mean age 9.4±2.91 years. The remaining 60(50%) were controls; 34(56.7%) males and 26(43.3%) females with mean age 9.7±2.99 years(p>0.05). Among the cases, 36(60%) had moderate severity and 24(40%) had mild asthma. Family history was positive in 11(18.3%) cases and negative in 49(81.7%). There was no significant difference in terms of conventional echocardiography between the groups (p>0.05). There was impairment in right ventricular diastolic function in the cases, with lateral tricuspid E` velocity significantly lower (p<0.05) and isovolumetric relaxation time significantly higher than the controls(p=0.001). There wasimpairment ofsystolic function of the right ventricle in the cases compared to the controls(p=0.001). Right ventricular peak longitudinalsystolic stress cut-off value distinguishing the controlsfrom the cases was -20.4 with sensitivity 85% and specificity 63%. The cut-off value distinguishing mild from moderate asthmatic cases was -19.8 with sensitivity 83% and specificity 91%. Speckle tracking echocardiography could detect very early subtle right ventricular systolic dysfunction. Right ventricle dysfunction worsened with the severity of asthma.

Regulating exchange dynamics in poly(β-hydrazide esters) via push-pull electronic effects towards covalent adaptable networks with fast reprocessing

Poly(β-hydrazide esters), prepared by the aza-Michael addition of a hydrazide to an acrylate moiety, have been used to accelerate the dissociation rates of dynamic aza-Michael adducts via push-pull electronic effects to create covalent adaptable networks (CANs) with faster reprocessing rates. Hydrazide precursors containing aryl groups that can conjugate with the carboxamide functionality can increase the electron density on the terminal amine of the hydrazide (push electronic effect). On the other hand, hydrazide precursors containing alkyl groups that cannot conjugate with the carboxamide will have terminal amines that are more electron-deficient since part of its electron density is donated to the carbonyl group (pull electronic effect). We used small molecule models of the CANs to show that the push electronic effect of the aryl carboxamide group accelerated the dissociation rates of the dynamic aza-Michael adducts and significantly increased the reversibility of the Michael addition. In contrast, the pull electronic effect of the alkyl carboxamide groups reduced the dissociation rates of the dynamic aza-Michael adducts. Likewise, when we examined the reprocessing of the CANs, the poly(β-hydrazide esters) with the push electronic effect had lower stress relaxation times (69–79 s) and reprocessing times than their congeners with the pull electronic effect (182–3760 s). They can be reprocessed at least 10 times when heated to 180 °C for 0.5 h. Regulating the thermal stability of the dynamic aza-Michael adducts can thus reduce the dependence of the reprocessing performance of the CANs on the boiling points of the monomers. In addition, these poly(β-hydrazide esters) show excellent heat resistance (Tg = 113 °C andTd-5% = 279 °C). Thus, the push-pull electronic effect of the carboxamide groups provides a useful strategy to regulate the reversibility of the dynamic covalent bonds to achieve thermosets that can be reprocessed rapidly.

Au-Ag NPs embedded Sago Starch-Sodium Alginate composites: An investigation of structural, thermal and dielectric properties for applications in flexible electronic devices

Flexible bio-friendly nanocomposite (NC) films based on Sago Starch-Sodium Alginate (SS-SA) blend embedded with Auc-Ags core–shell nanoparticles (NPs) were synthesized via solution casting approach. The appearance of XRD peaks corresponding to Ag NPs confirms the formation of Ag shell over Au core and also evidenced by HR-TEM, SAED pattern, FE-SEM. Thermogravimetric analysis (TGA) suggests enhanced thermal stability with addition of NPs in polymer blend. Dielectric spectroscopy reveals that, dielectric permittivity (ε') of polymer matrix increases from 18.8 (at 100 Hz) to 96.2 at room temperature (for 1.5 wt% Auc-Ags@SS-SA NC), and increases to 2227.4 at 353 K. This increase is attributed to the formation of nano-capacitors. Enhanced ac conductivity, low relaxation time and decrease in grain/grain boundary resistances with the addition of Auc-Ags NPs indicate enhanced charge transport. Enhanced dielectric permittivity and low tangent loss make these NC films a potential contender for charge storage in flexible electronic devices.

Rheological behaviour of different composite materials for additive manufacturing of 3D bone scaffolds

The production of scaffolds for bone tissue applications is requiring a combination of physical and biological properties, which are depending on the materials morphology and pro-cessing conditions during the production process. The aim of the paper is the investigation of rheological behaviour of polymer and composite blends regularly used for the production of scaffolds for bone tissue applications with the use of additive manufacturing. Poly-ε-caprolactone (PCL), hydroxyapatite (HA), β-tri-calcium phosphate (TCP) and Bioglass 45S5 blends containing different ceramic concentrations (10 wt%, 15 wt% and 20 wt%) were prepared with the use of melt blending procedure and investigated with the use of oscillation and rotational rheology tests. Results are showing that all blends are presenting viscoelastic behaviour with higher viscous modulus, compared with elastic modulus for low frequencies, with this difference reducing while the frequency is increasing. All blends are presenting shear-thinning behaviour suitable for use with additive manufacturing methods. Viscous and elastic modulus are increasing by adding ceramic particles. Results are presenting that PCL/HA blends of the same material concentration are presenting higher elastic modulus properties compared with the other blends, while PCL/Bioglass blends are presenting lower loss factor, lower relaxation time and lower shear viscosity making them easier to handle during the printing procedure.

Spectroscopic measurement and dielectric relaxation study of vegetable oils

The purpose of the current study is to investigate the qualitative characterization of nine different pure vegetable oil samples using dielectric spectroscopy which is a vastly resourceful and reasoned technique in the temperature range 0 ℃ to 25 ℃. Time-domain reflectometry technique is applied up to the microwave frequencies of 50 GHz for the first time for qualitative characterization of the selected vegetable oil samples with a special focus on the variances of dielectric properties like dielectric permittivity (ε′), dielectric loss (ε″), relaxation time concerning temperature and other physiochemical properties of the vegetable oil specimens.The experimental methodology involves the use of time-domain reflectometry (TDR) measurements up to the scale of 50 GHz done to analyse the aspects like lower and higher scales of values towards the static dielectric permittivity (εs) and relaxation time (τ) (ps) to further meaningfully compare and correlate this values with the fatty acid profiles of each of the nine vegetable oil samples to reason and draw comparative inferences about the quality aspects of vegetable oils. Microwave TDR studies provide an effective, alternate, simple, rapid, and viable way to exercise quality control and actuate data regarding the quality status of vegetable oils. Variances of dielectric permittivity (ε′) concerning dielectric loss (ε″) are graphically interpreted using the Cole Davidson model. The static dielectric permittivity (εs) was further recertified and measured accurately by using a precision LCR meter. Thermodynamic properties of all the nine vegetable oil samples like enthalpy (ΔH) (kJ/mol) and entropy of activation (ΔS) (J/mol ∙ K) are also calculated to further insight the dependence of dielectric properties of these oil samples concerning temperature.This dielectric spectroscopic study affirms the association of the quality aspects of these nine vegetable oil samples with their dielectric properties by providing meaningful correlations, comparatives and concurrencies of dielectric properties concerning the physiochemical properties which are a part of fatty acid profiles of these samples, which is a novel aspect of this study. The Cole-Cole plot underlines the tendency of realignment of dipoles as per the applied field. The complex permittivity spectra indicate the dwindling nature of molecular alignment including a slow decline to average coinciding values depending on the molecular bonding pattern of vegetable oil samples. The activation energy (ΔH) in (kJ/mol) is calculated for all the samples which are indicative of endothermic nature which experimentally proves that high energy is required for rotation of unsaturated oil sample molecules with low relaxation times.The highlight of the current dielectric spectroscopic study is that it conclusively divides the nine vegetable oil samples into two groups based on the dielectric property of relaxation time. The vegetable oil samples with higher relaxation times were measured in ps [soyabean oil (398.5), groundnut oil (412.5), flaxseed oil (318.4), and castor oil (305.3)] and the oil samples with lower relaxation times [safflower oil (37.91), sunflower oil (30.6), walnut oil (22.4) and sesame oil (38.4)] and correlate this dielectric aspect with the aspect extent of the presence of oleic acid: C18H34O2, linoleic acid: C18H32O2, linolenic acid: C18H30O2 and ricinoleic acid C18H34O3 alongside the percentage of unsaturation present in the fatty acid profile of each sample. Saturated fatty profile of coconut oil (percentage of saturation 82.5) with low relaxation time (41.8) ps and its concurrency concerning the extent of percentage presence of lauric acid C12H24O2 (52 ps) myristic acid: C14H28O2 (21 ps) is also correlated. The current dielectric spectroscopic study further highlights and compares the variances of dielectric permittivity of the nine vegetable oils samples with the percentage of unsaturation /saturation to infer upon the correlation with the fatty acid profile of these oil samples.

The effect of propylene glycol addition on the flavour compounds retention of peppermint powders

AbstractCompared with peppermint oil, natural peppermint has more ingredients, a layered fragrance, and a green colour. It has been widely used as a nutritional additive, herbal tea, food flavouring or colouring. In this work, the retention of volatile flavour compounds of peppermint powders was enhanced by propylene glycol, a reagent that enhances hydrogen bonds and moisture absorption. The levels of influence of propylene glycol content on the retention of different volatile flavour compounds, moisture absorption and water distribution were evaluated by GC–MS, dynamic water absorption instrument (DVS), and low‐field nuclear magnetic resonance (LF‐NMR), respectively. GC–MS analysis showed that the volatile substances of peppermint powders (PMs) without propylene glycol were reduced to 22 kinds after storage for 90 days, and the total amount of volatile substances remained at 40.94%; PG2 with 2% propylene glycol had the best flavour retention. After 90 days of storage, the residual percentage of volatile flavour compounds of PG2 was approximately 72.56%, which was significantly increased compared with that of PM. The DVS results suggested that all the peppermint powders adopted a type III moisture absorption isotherm, and they all had multilayer adsorbed water. PG2 had the best moisture retention capacity and the highest hygroscopic hysteresis, while PG4 with a high propylene glycol content had a relatively poor moisture retention capacity. Similarly, LF‐NMR analysis showed that PG2 had a higher proportion of bound water and lower relaxation times T21 and T22 under different humidity conditions, indicating that it had the strongest water binding capacity. The correlation analysis showed that there was a significant positive correlation between the residual volatile compounds of peppermint powders and the peak area of bound water A21. The higher the proportion of strongly bound water in peppermint particles was, the more residual volatile substances were identified in peppermint particles. These results show that peppermint particles supplemented with propylene glycol can significantly improve the flavour retention ability of peppermint powders. In short, the results could be applied to the storage stability and quality control of peppermint products.

Ultrasonic Vitrectomy Performance Assessment Using Micro-Extensional Rheology.

The purpose of this study was to assess the performance of ultrasonic (US) vitrectomy devices by quantifying and comparing its impact on extracted vitreous properties to conventional pneumatic blade (PB) cutters using micro-extensional rheology. US vitrectomy is a new technology that offers an alternative to PB cutters used in vitreo-retinal surgeries. Thirty-six porcine vitreous samples were extracted using US and PB cutters. Each sample was kept at 4°C and tested within 24 hours postmortem and 4 hours post-vitrectomy. A recently developed micro-extensional rheology technique is used to infer the relative protein fragment size of extracted vitreous by quantifying the extensional relaxation time. US-extracted vitreous exhibited extensional relaxation times orders of magnitude lower than PB-extracted vitreous (0.37 ms and 27.25 ms, respectively). Relaxation time is directly correlated to the fragment size of the collagen fibers in the vitreous. The formation of beads-on-a-string droplets within the PB samples indicates the presence of larger collagen fragments. These droplets were not seen on US samples. This new micro-extensional rheology technique can identify significant differences in physical properties of extracted vitreous. Long relaxation times and beads-on-a-string droplets within the PB vitreous samples indicate larger protein fragments compared to the US samples. Higher fragmentation of vitreous and lower extensional relaxation times may improve retina safety due to a reduction in vitreo-retinal traction resulting from the continuous shear action and aspiration applied by ultrasonic vitrectomy technology.

Network structure of response to freeze-thaw cycles in egg white protein gels filled with emulsion: Digestive kinetics regulated by the state of water and embedded oil

In this paper, we focused on the effects of freeze-thaw treatment on the network structure of egg white protein (EWP) emulsion-filled gel (EFG). The freeze-thaw stability of EFG based on egg white protein was analyzed in terms of microstructure, digestive dynamics and processing properties in this work. The results showed that the initial spatial distribution of oil droplets and fine network of gel were damaged during freeze-thaw cycles observed by confocal laser scanning microscopy (CLSM). These phenomena led to the rising of swelling ratio (from 9.882% ± 0.535%–34.985% ± 1.843%) and the change of acid uptake process, which affected the pH value and pepsin activity inside gel. The effect of freeze-thaw cycles on amino acids release during digestion was evaluated by the model of digestive kinetics. Meanwhile, the characteristics of emulsion and gel matrix were detected, illustrating the effect of the ions and percentage of oil on gel subjected to freezing. With the repeats of freeze-thaw treatment, the initial gel network was reorganized for the thicker chain-like structure with higher cohesiveness (from 0.44 ± 0.014 to 0.75 ± 0.041), while ions could be used as stabilizer in frozen. Furthermore, the lower relaxation time proved the improved stability caused by ions, which resulted from the enhanced limitation of network structure to fillings. These findings provided valuable information on the relationship between the freeze-thaw stability of emulsion-filled gel and in vitro digestion, with a view to broader application in the direction of future fat replacement. • The well-distributed emulsion in gel would flocculate after freeze-thaw cycles. • Oil phase in gel promoted the structural changes of EFG during freeze-thaw cycles. • Freeze-thaw treatment slowed release of amino acid during the digestion of EFG. • LF-NMR proved the damage of bond between water and gel matrix due to freezing. • The properties of EFG after freezing were maintained by ions-induced firm structure.

Combined effects of drying methods and limited enzymatic hydrolysis on the physicochemical and antioxidant properties of rice protein hydrolysates

The combined effects of drying methods and limited enzymatic hydrolysis on the techno-functional characteristics of rice protein hydrolysates (RH) were investigated. With the increasing hydrolysis degree, the average size, exposed and total SH content, iron chelating capacity, hydroxyl and DPPH radical scavenging activity increased. Drying methods and enzyme type can alter the conformation of protein. Trypsin-derived spray dried RH exhibited higher α-helix contents while neutrase-derived ones had lower α-helix contents. The freeze-dried RH owed higher hydroxyl and DPPH scavenging activity than their spray-dried counterparts, which was related to higher sulfhydryl group and hydrophobic amino acids contents. RH derived from trypsin had higher metal chelating capacity than that from neutrase, which was in an agreement with higher amount of peptide <1000 Da. The shifting to lower relaxation time in spray-dried RH reflects lower water absorption capacity and slower water mobility, which are less susceptible to spoilage bacteria. Freeze drying would be a more prevalent technique for fully utilization of RH as bioactive components in the food system.

Multiphysics Experimental Approaches for Insight into the Hydrogen Bonded Structures of Ethylene Glycol and Glycerol Mixtures toward Green Solvent Technology

Alcohols and their mixtures are credited most important polar solvents for advances in pharmaceutical, chemical,biological, thermal, and material technologies. A rigorous study for the characterization of hydrogen bonded heterogeneousintermolecular structures that formed in a mixed solvent based on alcohols containing two and three hydroxyl groupsmolecules is crucial to specific technological and industrial applications. Hence, in this work, the multiphysics experimentalapproaches including the measurements of dielectric, electrical, viscous, acoustic, thermal, and optical properties are appliedand analyzed to confirm the behaviour of hydrogen bonded molecular structures of ethylene glycol (EG; dihydric alcohol)with glycerol (Gl; trihydric alcohol) over the entire concentration range of EG+Gl mixtures at 298.15 K. The static dielectricpermittivity, direct current electrical conductivity, low frequency relaxation time, and refractive index values of the EG+Glmixtures are reported. Additionally, dynamic viscosity, density, ultrasound velocity, adiabatic compressibility,intermolecular free length, acoustic impedance, free volume, Rao’s constant, Wada constant, and viscoacoustic relaxationtime of the EG+Gl mixtures are determined, and also explored their significance to these alcohols molecular interactions.Ultraviolet-visible range absorbance behaviour of the alcohol mixtures is characterized in detail and confirmed theelectronic transitions at higher energy ultraviolet radiations. The detailed analysis of all the experimental results along withthe consideration of excess properties evidenced the formation of heterogeneous intermolecular hydrogen bonded structuresin these Newtonian-type alcohols mixtures. A small to adequate variation in the thermodynamical and other investigatedproperties with the concentration variation showed that the EG+Gl mixture can be optimized as a green solvent according tothe prerequisite properties for huge advances in soft condensed matter technologies.

Ultrasonic-promoted defect activation and structural rejuvenation in a La-based metallic glass

Ultrasonic-assistant rejuvenation in a La-based metallic glass was demonstrated by means of nanoindentation for the first time. A more pronounced nanoindentation creep behavior along with mechanical softening was detected. It is proposed to be associated with the activation of flow defects with long characteristic relaxation time at a low loading rate and short characteristic relaxation time at a high loading rate during anelastic deformation process based on the Maxwell-Voigt model. Such rejuvenation behavior also leads to an unstable plastic flow and a relatively low energy barrier for atomic diffusion during the fast growth process of crystalline phases accompanied with the reduced glass transition and crystallization temperatures. Our studies might provide insights into the microscopic deformation mechanism of glassy materials, which could help in seeking the novel applications of amorphous alloys such as ultrasonic-assistant cold joining or molding.

Time-dependent hyper-viscoelastic parameter identification of human articular cartilage and substitute materials

Numerical simulations are a valuable tool to understand which processes during mechanical stimulations of hydrogels for cartilage replacement influence the behavior of chondrocytes and contribute to the success or failure of these materials as implants. Such simulations critically rely on the correct prediction of the material response through appropriate material models and corresponding parameters. In this study, we identify hyper-viscoelastic material parameters for numerical simulations in COMSOL Multiphysics® v. 5.6 for human articular cartilage and two replacement materials, the commercially available ChondroFillerliquid and oxidized alginate gelatin (ADA-GEL) hydrogels. We incorporate the realistic experimental boundary conditions into an inverse parameter identification scheme based on data from multiple loading modes simultaneously, including cyclic compression-tension and stress relaxation experiments. We provide individual parameter sets for the unconditioned and conditioned responses and discuss how viscoelastic effects are related to the materials’ microstructure. ADA-GEL and ChondroFillerliquid exhibit faster stress relaxation than cartilage with lower relaxation time constants, while cartilage has the largest viscoelastic stress contribution. The elastic response predominates in ADA-GEL and ChondroFillerliquid, while the viscoelastic response predominates in cartilage. These results will help to simulate mechanical stimulations, support the development of suitable materials with distinct mechanical properties in the future and provide parameters and insight into the time-dependent material behavior of human articular cartilage.

Improvement of extrudability and self-support of emulsion-filled starch gel for 3D printing: Increasing oil content

This work investigated the mechanism of increasing oil content in synchronously enhancing extrudability and self-support of β-carotene loaded starch-based emulsion-filled gels (S-EFG) during 3D printing in terms of gel properties. Increasing emulsion oil content enhanced the storage modulus, relaxation modulus, and hardness of gels, which indicated sodium caseinate-stabilized emulsions were active fillers in the starch gel. Thus, printed products with high oil content were less prone to collapse when selecting models with higher height. In addition, lower yield stress, relaxation time, and higher frequency dependence were observed in S-EFG with higher oil content (30–50 %) due to the lubricating/plasticizing effect of oils, which corresponded to the smoother extruded filament. Furthermore, the retention of β-carotene in high oil content gel was higher after heat treatment due to denser microstructure. These results indicated that the extrudability and self-supporting of S-EFG were simultaneously improved by increasing oil content under the active filling effect and lubricating/plasticizing effect of emulsions.

In vivo intervertebral disc mechanical deformation following a treadmill walking “stress test” is inversely related to T1rho relaxation time

To assess the in vivo relationship between the mechanical response of intervertebral discs (IVDs) to dynamic activity and IVD biochemical composition assessed via T1rho relaxation imaging. Eighteen asymptomatic participants with no history of low back pain (LBP), injury, or surgery underwent magnetic resonance (MR) imaging of their lumbar spine prior to and immediately following a treadmill walking "stress test." Anatomic (SPACE, FLASH) MR images were obtained pre- and post-exercise and utilized to measure IVD mechanical deformation. Quantitative (T1rho) imaging was performed pre-exercise to reflect IVD composition. Pre-exercise anatomic images were also utilized to assess IVD degenerative status based on the modified Pfirrmann scale. To quantify mechanical response, 3D surface models of the L1-L2-L5-S1 IVDs were created from manual segmentations of pre- and post-exercise anatomic images and utilized to assess changes in IVD height. IVD strain (%) was defined as change in IVD height normalized to pre-activity height. Linear mixed models were used to assess the relationships between IVD mechanical deformation (strain), composition (T1rho relaxation time), and degenerative status (Pfirrmann grade). Increased compressive IVD strain was associated with lower T1rho relaxation times in the nucleus pulposus (NP) of the disc (βT1rho=5.07,CI:[1.52,7.77],Rmarg2=0.52,p=0.005). Thus, an inverse relationship between IVD strain and NP T1rho relaxation time was observed. The in vivo mechanical response of the IVD to the "stress test" was sensitive to differences in NP composition. The results of this study suggest that quantification of in vivo IVD mechanical function and composition may provide insight into IVD health.

Hydrate phase equilibria in natural sediments: Inhibition mechanism and NMR-based prediction method

The hydrate phase equilibrium condition in natural sediments is an important prerequisite for gas hydrate exploitation and subsea sequestration of CO2. However, its rapid and accurate prediction remains a challenge. In this work, we proposed a novel method to predict the hydrate phase equilibria in various natural sediments using low-field NMR technology. Also, its potential inhibition mechanism was clarified from the perspective of different types of pore water. The results indicated the peaks of T2 spectra for all types of pore water shifted to lower transverse relaxation times during the hydrate formation, meaning that the formed hydrates act as solid matrices in sediments and thus reduce pore size. Furthermore, it was observed that hydrate formation from bound water was much more difficult than capillary water, even at the same pore size. More importantly, not all bound water participated in hydrate formation. During the hydrate dissociation, montmorillonite exhibited the greatest dissociation temperature depression, followed by SA sediments, while illite and kaolin showed a relatively low inhibition on hydrate phase equilibria. This difference in dissociation temperature depression is attributed to water adsorption on the mineral surface and interlayer cation hydration, in addition to the capillary effect. Among them, the capillary-induced phase equilibrium inhibition is the lowest, followed by interlayer cation hydration, and mineral surface adsorption shows the most strong inhibition. Finally, the feasibility and validity of the NMR-based method in predicting the hydrate phase equilibrium condition in natural sediments were verified. These findings not only add further insights into the hydrate phase behavior in clayey-silty sediments but also provide an effective tool for rapid and accurate predictions of hydrate phase equilibria.

Inhibitory effect of chitosan coating on oil absorption in French fries based on starch structure and morphology stability

The effect of chitosan (CS) coating on oil absorption, water migration, starch structure and morphology in French fries was evaluated. The penetrated surface oil, structure oil, total oil content, and a* of coated fries decreased, while the water content, L*, b*, and hardness significantly (P < 0.05) increased compared to uncoated samples. 1 % CS-coated fries had the lowest oil content, which decreased by 43.0 % compared to uncoated samples. CS-coated fries had higher free water, and lower T2 relaxation time, immobile and binding water than the control. CS coating reduced the pores on the fries' surface and the interaction between oil and the component of fries, which was observed by confocal laser scanning microscopy and scanning electron microscopy (SEM). As for starch morphology, the pores and cracks of starch granules in the coated samples reduced. As for the starch structure, the relative crystallinity, R1047/1022 respectively increased by 47.2 % and 2.35 times, and ΔH of CS-coated fries increased from 0 to 2.09 J/g, indicating that the long-range crystalline structure, short-range ordered structure, and hydrogen bonds between the double helices in starch increased. Therefore, CS coating reduced oil penetration into fries by reducing water migration and increasing starch ordered structure and morphological integrity.

Steepest entropy ascent solution for a continuous-time quantum walker.

We consider the steepest entropy ascent (SEA) ansatz to describe the nonlinear thermodynamic evolution of a quantum system. Recently this principle has been dubbed the fourth law of thermodynamics [Beretta, Phil. Trans. R. Soc. A 378, 20190168 (2020)10.1098/rsta.2019.0168]. A unique global equilibrium state exists in this context, and any other state is driven by the maximum entropy generation principle towards this equilibrium. We study the SEA evolution of a continuous-time quantum walker (CTQW) on a cycle graph with N nodes. SEA solutions are difficult to find analytically. We provide an approximate scheme to find a general single-particle evolution equationgoverned by the SEA principle, whose solution produces dissipation dynamics. We call this scheme the fixed Lagrange's multiplier (FLM) method. In the Bloch sphere representation, we find trajectories traced out by the Bloch vector within the sphere itself. We have discussed these trajectories under various initial conditions for the case of a qubit. A similar dissipative motion is also observed in the case of CTQW, where probability amplitudes have been used to characterize decoherence. Our FLM scheme shows good agreement with numerical results. As we report, in CTQW, a strong delocalization exists for low system relaxation time.