The manufacture, optical properties, and mechanical aspects of europium-doped borate glasses.

An investigation into the optical and mechanical properties of a novel borate glasses with the chemical composition of 70 B2O3-10 Li2O-10ZnO-5Bi2O3-5CaO-xEu2O3 was conducted. The glassy specimens of Eu3+-doped borate were prepared by the melting-quenching technique. An enhanced density from 3.0860 to 3.2176 g cm-3 and reduced molar volume from 29.27819 to 29.17447 (cm3 mol-1) are the outcome of increasing the concentration of Eu3+ in glasses. Plotting the extinction coefficient, dielectric constant (ε1, ε2), and refractive index (n) against wavelength reveals that they all rise as level of Eu3+ elements in the glass lattice increases. An increase in Eu3+ concentration results in a decrease in both the volume (VELF) and surface (SELF) energy loss functions. Also, all elastic-mechanical moduli (such as Young's, Bulk, Shear, and Elongation) increase with increasing the quantity of Eu3+ ions in the glass lattice. The Young's modulus (Y, GPa) of the glassy specimens was 34.512, 36.089, 36.504, 36.730 and 37.114 GPa for x equal 0, 0.25, 0.5, 0.75 and 1 mol ratio in the glass system, and coded by Eu-0.0, Eu-0.25, Eu-0.5, Eu-0.75 and Eu-1.0, respectively. Growing Eu2O3 levels resulted in an increase in Micro-Hardness from 2.050 to 2.146 GPa. Poisson's ratio values for Eu-0.0, Eu-0.250, Eu-0.5, Eu-0.75 and Eu-1.0 were 0.273, 0.275, 0.277, 0.277 and 0.278, respectively.

Application of real-time shear wave elastography to Achilles tendon hardness evaluation in older adults.

BACKGROUND: Real-time shear wave elastography (SWE) is a non-invasive imaging technique used to measure tissue stiffness by generating and tracking shear waves in real time. This advanced ultrasound-based method provides quantitative information regarding tissue elasticity, offering valuable insights into the mechanical properties of biological tissues. However, the application of real-time SWE in the musculoskeletal system and sports medicine has not been extensively studied. AIM: To explore the practical value of real-time SWE for assessing Achilles tendon hardness in older adults. METHODS: A total of 60 participants were enrolled in the present study, and differences in the elastic moduli of the bilateral Achilles tendons were compared among the following categories: (1) Age: 55-60, 60-65, and 65-70-years-old; (2) Sex: Male and female; (3) Laterality: Left and right sides; (4) Tendon state: Relaxed and tense state; and (5) Tendon segment: Proximal, middle, and distal. RESULTS: There were no significant differences in the elastic moduli of the bilateral Achilles tendons when comparing by age or sex (P > 0.05). There were, however, significant differences when comparing by tendon side, state, or segment (P < 0.05). CONCLUSION: Real-time SWE plays a significant role compared to other examination methods in the evaluation of Achilles tendon hardness in older adults.

Evaluation of the Mechanical Behavior of the Patellar and Semitendinosus Tendons Using Supersonic Shear-wave Imaging (SSI) Elastography and Tensile Tests.

Objective To analyze the mechanical properties of the patellar (PT) and semitendinosus (ST) tendons from fresh-frozen human cadavers from a tissue bank using supersonic shear-wave imaging (SSI) elastography and tensile tests. Methods We tested seven PT and five ST samples on a traction machine and performed their simultaneous assessment through SSI. The measurements enabled the comparison of the mechanical behavior of the tendons using the stress x strain curve and shear modulus (µ) at rest. In addition, we analyzed the stress x µ relationship under tension and tested the relationship between these parameters. The statistical analysis of the results used unpaired t -tests with Welch correction, the Pearson correlation, and linear regression for the Young modulus (E) estimation. Results The µ values for the PT and ST at rest were of 58.86 ± 5.226 kPa and 124.3 ± 7.231 kPa respectively, and this difference was statistically significant. The correlation coefficient between stress and µ for the PT and ST was very strong. The calculated E for the PT and ST was of 19.97 kPa and 124.8 kPa respectively, with a statistically significant difference. Conclusion The ST was stiffer than the PT in the traction tests and SSI evaluations. The µ value was directly related to the stress imposed on the tendon. Clinical relevance The present is an evaluation of the mechanical properties of the tendons most used as grafts in knee ligament reconstruction surgeries.

High Young's Modulus LixTiO2 Layer Suppressing the Pulverization and Deactivation of Lithiophilic Ag Nanoparticles.

Anode-free Lithium metal batteries, with their high energy density (>500 Wh/kg), are emerging as a promising solution for high-energy-density rechargeable batteries. However, the Coulombic Efficiency and capacity often decline due to interface side reactions. To address this, a lithiophilic layer is introduced, promoting stable and uniform Li deposition. Despite its effectiveness, this layer often undergoes electrochemical deactivation over time. This work investigates lithiophilic silver (Ag), prepared via magnetron sputtering on a copper (Cu) current collector. Finite element simulations identify stress changes from alloying reactions as a key cause of Ag particle pulverization and deactivation. A high Young's modulus coating layer is proposed to mitigate this. The Ag2TiO3@Ag@TiO2@Cu composite electrode, designed with multi-layer structures, demonstrates a slower deactivation process through galvanostatic electrochemical cycling. Characterization methods such as SEM, AFM, and TEM confirm the suppression of Ag particle pulverization, while uncoated Ag fractures and deactivates. This work uncovers a potential failure mechanism of lithiophilic metallic nanoparticles and proposes a strategy for deactivation suppression using an artificial coating layer.

Characterization of the Vertical Stiffness Gradient in Cadaveric Human and Excised Canine Larynges.

The elastic properties of the folds govern the characteristics of vocal fold vibrations. This study addresses existing gaps by investigating the Young's modulus along the anterior-posterior direction in excised canine and cadaveric human vocal folds. Micro-indentation testing was conducted on six excised canines and three cadaveric human larynges. Multiple points along the medial glottal wall were indented to determine force-displacement, stress-strain relationships, and Young's modulus as a function of Green's strain. A vertical stiffness gradient was consistently observed in both canine and human samples, with higher stiffness in the inferior aspect compared with the superior aspect. The stiffness increased toward both the anterior and posterior directions from the mid-coronal plane, with a more pronounced increase at the posterior edge. Human vocal folds generally exhibited lower stiffness at low strains but were comparable to canine vocal folds at higher strains. These findings suggest that the canine larynx model is a reasonable representation of the human laryngeal tissues' elastic property trends. This analysis of the vertical stiffness gradient in canine and human vocal folds provides valuable data for improving experimental and numerical models of phonation.

A new method for identifying elastic parameters of isotropic materials based on square specimens.

This paper proposes a new impulse excitation technique using a square plate. First, the functional relationship between the modal frequency of the specimen and the geometrical dimensions and mechanical parameters was established by using the finite element method. Then, the continuous functional relationship derived by a homotopy method allowed the frequency ratios to be related to the thickness-to-length ratio and Poisson's ratio. By measuring the frequency ratios and thickness-to-length ratio, Poisson's ratio could be calculated using this functional relationship. When the density and Poisson's ratio were known, Young's modulus could be identified inversely in conjunction with the finite element analysis. Finally, a comparison test between this method and the traditional impulse excitation technique was designed and implemented, and the results showed that this method has advantages in both testing efficiency and accuracy. The study provides a new idea for system identification, which has important application value and promotion significance.

Prediction of Mechanical Properties of Lattice Structures: An Application of Artificial Neural Networks Algorithms.

The yield strength and Young's modulus of lattice structures are essential mechanical parameters that influence the utilization of materials in the aerospace and medical fields. Currently, accurately determining the Young's modulus and yield strength of lattice structures often requires conduction of a large number of experiments for prediction and validation purposes. To save time and effort to accurately predict the material yield strength and Young's modulus, based on the existing experimental data, finite element analysis is employed to expand the dataset. An artificial neural network algorithm is then used to establish a relationship model between the topology of the lattice structure and Young's modulus (the yield strength), which is analyzed and verified. The Gibson-Ashby model analysis indicates that different lattice structures can be classified into two main deformation forms. To obtain an artificial neural network model that can accurately predict different lattice structures and be deployed in the prediction of BCC-FCC lattice structures, the artificial network model is further optimized and validated. Concurrently, the topology of disparate lattice structures gives rise to a certain discrete form of their dominant deformation, which consequently affects the neural network prediction. In conclusion, the prediction of Young's modulus and yield strength of lattice structures using artificial neural networks is a feasible approach that can contribute to the development of lattice structures in the aerospace and medical fields.

Theory and Measurement of Heat Transport in Solids: How Rigidity and Spectral Properties Govern Behavior.

Models of heat transport in solids, being based on idealized elastic collisions of gas molecules, are flawed because heat and mass diffuse independently in solids but together in gas. To better understand heat transfer, an analytical, theoretical approach is combined with data from laser flash analysis, which is the most accurate method available. Dimensional analysis of Fourier's heat equation shows that thermal diffusivity (D) depends on length-scale, which has been confirmed experimentally for metallic, semiconducting, and electrically insulating solids. A radiative diffusion model reproduces measured thermal conductivity (K = DρcP = D × density × specific heat) for thick solids from ~0 to >1200 K using idealized spectra represented by 2-4 parameters. Heat diffusion at laboratory temperatures (conduction) proceeds by absorption and re-emission of infrared light, which explains why heat flows into, through, and out of a material. Because heat added to matter performs work, thermal expansivity is proportional to ρcP/Young's modulus (i.e., rigidity or strength), which is confirmed experimentally over wide temperature ranges. Greater uptake of applied heat (e.g., cP generally increasing with T or at certain phase transitions) reduces the amount of heat that can flow through the solid, but because K = DρcP, the rate (D) must decrease to compensate. Laser flash analysis data confirm this proposal. Transport properties thus depend on heat uptake, which is controlled by the interaction of light with the material under the conditions of interest. This new finding supports a radiative diffusion mechanism for heat transport and explains behavior from ~0 K to above melting.

Impact of Regular and Irregular Pore Distributions on the Elasticity of Porous Materials: A Microstructure-Free Finite Element Study.

Conventional analytical formulas for predicting the effective Young's modulus of porous materials often rely on simplifying assumptions and do not explicitly incorporate microstructural information. This study investigates the impact of regular versus irregular pore distributions on the stiffness of porous materials using microstructure-free finite element modeling (MF-FEM). After conducting a convergence study, MF-FEM predictions were validated against experimental data and used to assess the accuracy of commonly employed analytical models. The results demonstrate that materials with irregular microstructures exhibit a rapid decrease in Young's modulus, approaching zero at porosities slightly greater than 50%. In contrast, regular microstructures show a more gradual decline, maintaining significant stiffness until the porosity exceeds 90%. Additionally, the study reveals that some analytical formulas align better with irregular microstructures while others are more suited to regular ones, attributable to the underlying assumptions of these models. These findings underscore the necessity of considering pore distribution patterns in modeling to accurately predict the mechanical behavior of porous materials.

Interrelation of macroscopic mechanical properties and molecular scale thermal relaxation of biodegradable and non-biodegradable polymers.

Comparative analysis of macroscopic mechanical properties of a biodegradable polymer polypropylene carbonate (PPC) is carried out concerning two most commonly used, non-biodegradable synthetic polymers - high-density polyethylene (HDPE) and linear-low density polyethylene (LLDPE). Responses of the films of these polymers when subjected to mechanical and thermal stresses are analyzed. Response to tensile stress reveals the highest elongation at break (EB) in PPC films (396 $\pm$ 104 mm), compared to HDPE (26 $\pm$ 0.5 mm) and LLDPE (301 $\pm$ 143 mm), although the elastic modulus (YM) of PPC is around 50 $\pm$ 6 MPa, 3-fold lesser than LLDPE (YM = 153 $\pm$ 7 MPa) and 6-fold lesser than HDPE (YM = 305 $\pm$ 32 MPa). The plastic deformation response of PPC is intermediate to that of HDPE and LLDPE; initial strain softening is followed by strain hardening in LLDPE, a plateau region in PPC, and prolonged strain softening in HDPE. Crystalline domains in HDPE produce restriction on molecular motion. Crystallinity abruptly decreases by 70 \% in HDPE following a thermal quench, showing the possibility of free chain molecular mobility during plastic deformation. High correlation among Raman modes for all polymers reveals cooperative relaxation processes after thermal quench; C-C stretching modes and C-H bending, CH$_2$ wagging modes have Pearson's correlation coefficient 0.9. The integrated peak intensity and width of the C-C stretching Raman mode is 3-fold higher in PPC than HDPE after a thermal quench, showing enhanced molecular mobility and contributing modes in PPC. The peak width of this mode shows a strong negative correlation of -0.7 with the YM and a strong positive correlation of 0.6 with EB, showing that higher amorphicity leads to enhanced molecular mobility and EB at the cost of YM. This study reveals importance of molecular-scale response in governing the macroscopic properties of polymers.

Phosphatidylserine-functional polydimethylsiloxane substrates regulate macrophage M2 polarization via modulus-dependent NF-κB/PPARγ pathway.

Macrophages, highly plastic innate immune cells, critically influence the success of implantable devices by responding to biochemical and physical cues. However, the mechanisms underlying their synergistic regulation of macrophage polarization on implant surfaces remain poorly understood. Therefore, we constructed anti-inflammatory phosphatidylserine (PS) modified polydimethylsiloxane (PDMS) substrates with low, medium, and high modulus (1-100 kPa) to investigate the combined effects and underlying mechanisms of substrate modulus and biochemical signal on macrophage polarization. The introduction of PS on the PDMS surface not only significantly enhanced the polarization of M0 to M2 but also potently suppressed lipopolysaccharide (LPS)-induced M1 activation, with this effect further potentiated by a reduction in substrate modulus. In vivo subcutaneous implantation experiments also corroborated the synergistic effect of PS functionalization and low modulus PDMS in inhibiting M1 activation and promoting M2 polarization. Notably, reduced modulus led to decreased integrin αV/ß3 clustering and cytoskeletal protein aggregation, ultimately diminishing YAP activation and nuclear translocation. Concomitantly, this disruption of the Piezo1-cytoskeletal protein positive feedback loop resulted in reduced p65/IκB phosphorylation and inflammation, while concurrently promoting PPARγ expression. Overall, our findings underscore the pivotal role of substrate modulus in modulating PS-mediated biomaterial-cell interactions, synergistically potentiating PS-induced M2 macrophage polarization, thus paving the way for the design of advanced immunomodulatory biomaterials.

Mechanical properties of additively manufactured lattice structures composed of zirconia and hydroxyapatite ceramics.

Ceramic lattices hold great potential for bone scaffolds to facilitate bone regeneration and integration of native tissue with medical implants. While there have been several studies on additive manufacturing of ceramics and their osseointegrative and osteoconductive properties, there is a lack of a comprehensive examination of their mechanical behavior. Therefore, the aim of this study was to assess the mechanical properties of different additively manufactured ceramic lattice structures under different loading conditions and their overall ability to mimic bone tissue properties. Eleven different lattice structures were designed and manufactured with a porosity of 80% using two materials, hydroxyapatite (HAp) and zirconium dioxide (ZrO2). Six cell-based lattices with cubic and hexagonal base, as well as five Voronoi-based lattices were considered in this study. The samples were manufactured using lithography-based ceramic additive manufacturing and post-processed thermally prior to mechanical testing. Cell-based lattices with cubic and hexagonal base, as well as Voronoi-based lattices were considered in this study. The lattices were tested under four loading conditions: compression, four-point bending, shear and tension. The manufacturing process of the different ceramics leads to different deviations of the lattice geometry, hence, the elastic properties of one structure cannot be directly inferred from one material to another. ZrO2 lattices prove to be stiffer than HAp lattices of the same designed structure. The Young's modulus for compression of ZrO2 lattices ranges from 2 to 30GPa depending on the used lattice design and for HAp 200MPa to 3.8GPa. The expected stability, the load where 63.2% of the samples are expected to be destroyed, of the lattices ranges from 81 to 553MPa and for HAp 6 to 42MPa. For the first time, a comprehensive overview of the mechanical properties of various additively manufactured ceramic lattice structures is provided. This is intended to serve as a reference for designers who would like to expand the design capabilities of ceramic implants that will lead to an advancement in their performance and ability to mimic human bone tissue.

Age-dependence of semitendinosus tendon properties used for anterior cruciate ligament reconstruction differs in males and females.

BACKGROUND: The semitendinosus tendon is one of the most used autografts in anterior cruciate ligament reconstruction. Although recent evidence indicates that young patients, especially in females, may experience high rates of revision and residual instability, the reasons for the inferior outcomes in these patients remain unclear. To address this issue, we aimed to compare the mechanical properties of the semitendinosus tendon used for anterior cruciate ligament reconstruction in male and female patients of various ages. METHODS: The semitendinosus tendons harvested from 31 male and 29 female patients who underwent anterior cruciate ligament reconstruction surgery using the semitendinosus tendon autografts were used in this study. Using the distal part of the harvested semitendinosus tendon, the extent of cyclic loading-induced elongation (i.e., the extent of the increase in slack length) and the Young's modulus were measured during cyclic tensile testing. FINDINGS: Spearman correlation analyses revealed that the Young's modulus (|ρ| = 0.725, P < 0.001), but not elongation (|ρ| ≤ 0.036, P ≥ 0.351) positively correlated with the patient age in male tendon samples. In contrast, for female tendon samples, the elongation (|ρ| ≥ 0.415, P ≤ 0.025), but not the Young's modulus (|ρ| = 0.087, P = 0.655) negatively correlated with the patient age. INTERPRETATION: These results indicate that the semitendinosus tendon used for anterior cruciate ligament reconstruction in young male patients is compliant, whereas that in young female patients is susceptible to elongation induced by cyclic loading.

High-intensity resistance training and collagen supplementation improve patellar tendon adaptations in professional female soccer athletes.

We investigated whether 10 weeks of pre-season soccer training (including high-intensity resistance exercise) with hydrolysed collagen (COL) supplementation would confer greater changes in patellar tendon (PT) mechanical and material properties compared with placebo (PLA) in professional female soccer athletes. Eleven athletes from the first team squad of a Football Association Women's Championship soccer club volunteered to participate in this study (age, 25.7 ± 4.2 years; height, 1.68 ± 0.04 m; mass, 64.0 ± 4.6 kg). Participants were pair-matched for baseline knee extensor maximum isometric voluntary contraction torque, age, height and mass and were randomly assigned to the COL group (n = 6) or PLA group (n = 5). Participants were given 30 g COL or energy-matched (36.5 g maltodextrin and 8.4 g fructose) PLA, plus 500 mg vitamin C before each training session, which consisted of high-intensity lower-limb resistance exercise, plyometric or pitch-based exercise 3 days/week for 10 weeks during the pre-season period. We assessed knee extensor maximum isometric voluntary contraction torque and PT properties using isokinetic dynamometry and ultrasonography before and after the intervention. The PT stiffness [COL, +15.4% ± 3.1% (d = 0.81) vs. PLA, +4.6% ± 3.0% (d = 0.32), P = 0.002] and Young's modulus [COL, +14.2% ± 4.0% (d = 0.65) vs. PLA, +3.4% ± 2.8% (d = 0.15), P = 0.004] increased more in COL than in PLA. There was a main effect of training on PT cross-sectional area (P = 0.027), but no interaction effect (P = 0.934). To conclude, 10 weeks of pre-season soccer training (incorporating high-intensity resistance exercise) with 30 g COL increased PT stiffness and Young's modulus more than training alone in professional female soccer athletes. This has positive implications for improving athletic performance and mitigating injury risk.

The Utilization of Brillouin Microscopy in Corneal Diagnostics: A Systematic Review.

Corneal biomechanical data has been used since 2005 to screen for keratoconus and corneal ectasia by corneal specialists. Older technology uses force applanation techniques over a 3 mm area in the central cornea, making it highly dependent on extraneous variables and unable to calculate the elasticity of the tissue. Brillouin microscopy is a newer method that uses a natural shift in the frequency of light as it passes through a material. This frequency shift can be used to estimate the viscoelasticity of the tissue. The advantage of Brillouin microscopy is that it can create a full three-dimensional (3D) map of the entire cornea without direct contact. A literature search was conducted using the databases PubMed, Google Scholar, and Ovid regarding the applications of Brillouin microscopy in corneal diagnostics. A final total of 16 articles was included describing the various ex vivo and in vivo studies conducted using Brillouin microscopy. Applications of this technology spanned from keratoconus diagnosis to post-corneal refractive surgery evaluation. All studies evaluated corneal biomechanics and other corneal properties through the quantification of Brillouin frequency shifts. Many of the studies found that this diagnostic device is capable of detecting subtle changes in corneal thickness and biomechanics in keratoconic corneas at a high level of specificity and sensitivity. However, limitations of Brillouin microscopy may include the duration of time required for use and fluctuations in accuracy depending on the corneal hydration state. Future technology seems to be geared toward a combination of optical coherence tomography (OCT) and Brillouin microscopy, using OCT as a three-dimensional pupil-tracking modality. Further research and understanding of the technology involved will lead to better care of patients in the field of ophthalmology.

Cold Storage of Human Femoral Arteries for Twelve Months: Impact on Mechanical Properties.

OBJECTIVE: This biomechanical pre-clinical study aimed to assess the consequences on mechanical properties of long term cold storage (+2 to +8 °C) of arterial allografts. METHODS: Femoropopliteal arterial segments were collected from multiorgan donors and stored at +2 to +8 °C for twelve months in saline solution with added antibiotics. Mechanical characterisation was carried out using two different tests, with the aim of defining the physiological modulus and the maximum stress and strain borne by the sample before rupture. These characterisations were carried out after zero, six, and twelve months of storage for each sample (T0, T6, and T12, respectively). For comparison, the same tests were performed on cryopreserved femoropopliteal segments after thawing. RESULTS: Twelve refrigerated allografts (RAs), each divided into three segments, and 10 cryopreserved allografts (CAs) were characterised. The median (interquartile range [IQR]) Young's modulus was not statistically significantly different between the storage times for cold stored allografts: RAT0, 164 (150, 188) kPa; RAT6, 178 (141, 185) kPa; RAT12, 177 (149, 185) kPa. The median (IQR) Young's modulus of the CA group (153; 130, 170 kPa) showed no significant differences from the RA groups, irrespective of storage time. Furthermore, median (IQR) maximum stress and strain values were not significantly different between the different groups: for maximum stress: RAT0, 1.58 (1.08, 2.09) MPa; RAT6, 1.74 (1.55, 2.36) MPa; RAT12, 2.25 (1.87, 2.53) MPa; CA, 2.25 (1.77, 2.61) MPa; and for maximum strain: RAT0, 64% (50, 90); RAT6, 79% (63, 84); RAT12, 72% (65, 86); CA, 67% (50, 95). CONCLUSION: Cold storage for up to twelve months appears to have no impact on the mechanical characteristics of human arterial allografts. Therefore, this preservation method, which would greatly simplify routine care, seems feasible. Other indicators are being studied to verify the safety of this preservation process before considering its use in vivo.

Assessing tissue mechanical properties: Development of a custom-made tensile device and application on rodents sciatic nerves.

The development of biomaterials such as synthetic scaffolds for peripheral nerve regeneration requires a precise knowledge of the mechanical properties of the nerve in physiological-like conditions. Mechanical properties (Young's modulus, maximum stress and strain at break) for peripheral nerves are scarce and large discrepancies are observed in between reports. This is due in part to the absence of a robust testing device for nerves. To overcome this limitation, a custom-made tensile device (CMTD) has been built. To evaluate its reproducibility and accuracy, the imposed speed and distance over measured speed and distance was performed, followed by a validation using poly(dimethylsiloxane) (PDMS), a commercial polymer with established mechanical properties. Finally, the mechanical characterization of rodents (mice and rats) sciatic nerves using the CMTD was performed. Mouse and rat sciatic nerves Young's modulus were 4.57 ± 2.04 and 19.2 ± 0.86 MPa respectively. Maximum stress was 1.26 ± 0.56 MPa for mice and 3.81 ± 1.84 MPa for rats. Strain at break was 53 ± 17% for mice and 32 ± 12% for rats. The number of axons per sciatic nerve was found to be twice higher for rats. Statistical analysis of the measured mechanical properties revealed no sex-related trends, for both mice and rats (except for mouse maximum stress with p=0.03). Histological evaluation of rat sciatic nerve corroborated these findings. By developing a robust CMTD to establish the key mechanical properties (Young's modulus, maximum stress and strain at break) values for rodents sciatic nerves, our work represent an essential step toward the development of better synthetic scaffolds for peripheral nerve regeneration.

Nitrogen Gas-Assisted Extrusion for Improving the Physical Quality of Pea Protein-Enriched Corn Puffs with a Wide Range of Protein Contents.

Blowing agent-assisted extrusion cooking is a novel processing technique that can alter the expansion of extruded snacks and, thus, enhance their physical appeal, such as texture. However, to this day, this technique has only been studied for ingredients with limited protein contents (<30%). In this study, protein-enriched snacks were extruded using nitrogen gas as a blowing agent at a wide protein range (0-50%) to better explore the potential of this technique in manufacturing high-protein snacks. The results showed that, with nitrogen gas injection, extrudate radial expansion was significantly (p < 0.05) improved at 10% and 40% protein, while extrudate density was significantly reduced at 30% and 50% protein. Nitrogen gas-injected extrudates, especially at 50% protein, exhibited improvements in texture, including a reduction in hardness and an increase in crispness. Collectively, this study showed the promising potential of nitrogen gas-assisted extrusion in improving the physical appeal of innovative healthy snacks at a high protein level (i.e., 50%).

Fabrication of Apparatus Specialized for Measuring the Elasticity of Perioral Tissues.

On the human face, the lips are one of the most important anatomical elements, both morphologically and functionally. Morphologically, they have a significant impact on aesthetics, and abnormal lip morphology causes sociopsychological problems. Functionally, they play a crucial role in breathing, articulation, feeding, and swallowing. An apparatus that can accurately and easily measure the elastic modulus of perioral tissues in clinical tests was developed, and its measurement sensitivity was evaluated. The apparatus is basically a uniaxial compression apparatus consisting of a force sensor and a displacement sensor. The displacement sensor works by enhancing the restoring force due to the deformation of soft materials. Using the apparatus, the force and the displacement were measured for polyurethane elastomers with various levels of softness, which are a model material of human tissues. The stress measured by the developed apparatus increased in proportion to Young's modulus, and was measured by the compression apparatus at the whole region of Young's modulus, indicating that the relation can be used for calibration. Clinical tests using the developed apparatus revealed that Young's moduli for upper lip, left cheek, and right cheek were evaluated to be 45, 4.0, and 9.9 kPa, respectively. In this paper, the advantages of this apparatus and the interpretation of the data obtained are discussed from the perspective of orthodontics.

Explore the Pattern of Biomechanical Alterations in Vocal Fold Scar and Its Objective Quantitative Assessment Method.

OBJECTIVES: This research aims to discern the evolving nature of the biomechanical properties of vocal fold scarring by calculating Young's modulus for the vocal fold cover layer, the body layer, and the structure as a whole. The study also investigates the potential of diffusion tensor imaging (DTI) for determining these biomechanical characteristics quantitatively. METHODS: A total of six adult female Beagles were divided into two groups (A and B groups) for the creation of unilateral vocal fold scar models, each group containing three subjects. Five months postmodel creation, larynxes were excised and placed within a 9.4T BioSpec MRI system (Bruker, Germany) for scanning. Subsequently, the vocal folds were segregated from the larynx. In A group of Beagles, the vocal fold cover layer and body layers were separated, whereas in B group they remained intact. All samples were then subjected to cyclic tensile testing using an Instron MicroTester 5948, with Young's modulus computed for the vocal fold cover layer and body layers in the A group and for the intact vocal fold in the B group. Differences in the overall Young's modulus between the vocal fold scarred side and the healthy side were analyzed, and a Pearson correlation analysis was performed between DTI parameters and the outcomes of the stress-strain experiments. RESULTS: A statistically significant discrepancy in the overall Young's modulus was identified between the scar and healthy sides of the vocal fold (P = 0.0401). The Young's modulus also displayed a significant difference between the scar and healthy sides of the vocal fold cover layer (P = 0.0241). No meaningful divergence was observed in the elastic modulus between the scar and healthy sides of the vocal fold body layer (P > 0.05). Postseparation, Young's modulus for both the cover and body layers of the scarred vocal fold were less than that of the same layers on the healthy side. However, Young's modulus of the entirety of the vocal fold on the scar side was greater than that of the whole vocal fold on the healthy side. The fractional anisotropy (FA) of the vocal fold cover layer had a significant correlation with the elastic modulus (r = 0.812, P = 0.050), as did the Tensor trace (r = -0.821, P = 0.045). The FA of the vocal fold body layer showed no significant correlation with the elastic modulus (r = -0.725, P = 0.103), while the Tensor trace demonstrated a significant correlation (r = 0.911, P = 0.012). CONCLUSIONS: Biomechanical alterations in vocal fold scars demonstrate a closer association with adhesion bands, thus emphasizing the importance of adhesion band loosening for the restoration of vibratory function within vocal fold scarring. DTI emerges as a potent noninvasive quantitative instrument for assessing these biomechanical changes, as well as for quantitatively gauging the severity of vocal fold scarring.