Impact of different fibrin glue application methods on inguinal hernia mesh fixation capability.

The use of fibrin glue for inguinal hernia mesh fixation has been suggested to be effective in preventing hematomas and reducing postoperative pain compared to tacks and sutures.. The effect of fibrin glue can vary significantly based on the device used. This study assessed the efficacy of fibrin glue based on the type of devices used in an ex vivo system. The rabbit's abdominal wall was trimmed to a size of 3.0 × 6.0 cm and was secured at the edges with metal fixtures. To measure the maximum tensile strength at the point of adhesion failure, the hernia mesh was fixed to the rabbit's abdominal wall using fibrin glue in a 2 cm square area, left for 3 min, and then pulled at a speed of 50 cm/min. The test was conducted 10 times for each group. The median (minimum-maximum) tensile strength values using the spraying, two-liquid mixing, and sequential layering methods were 3.58 (1.99-4.95), 0.51 (0.27-1.89), and 1.32 (0.63-1.66) N, respectively. The spraying method had predominantly higher tensile strength values than the two-liquid mixing and sequential layering methods (P < 0.01). In conclusion, in hernia mesh fixation, the spraying method can be adopted to achieve appropriate adhesive effects.

Preparation of films based on reticulated fish gelatin containing garlic essential oil.

Agro-industrial co-products, such as fish gelatin, stand out for their capacity in forming biopolymeric films, being biocompatible and non-toxic; however, its hydrophilicity poses a challenge. Essential oils, rich in bioactives, attract research interest aiming to enhance the protective barrier of films and enable their application in packaging. This study produced films based on cross-linked Nile tilapia skin gelatin, incorporating garlic essential oil. Gelatin obtained through partial collagen hydrolysis from the fish skin and cross-linked with gallic acid had hydroxyproline content of 10.02 g 100 g-1 and gel strength of 287 g, which were consistent with other studies. Oil extraction used supercritical CO2 as a solvent and ethanol as a cosolvent, following a factorial experimental design, evaluating the extraction temperature (40 °C and 70 °C) and cosolvent ratio (1:1 and 1:3), with three central points. Extraction was successful, with higher yields on a dry basis at 70 °C (88.35 %), using a 1:1 cosolvent ratio. Films incorporated with oil exhibited lower water vapor permeability (WVP) than those with only cross-linked gelatin (1.59 (g m-1 s-1 Pa-1) 1011). The film with the most suitable tensile strength (19.07 MPa), elongation (120.91 %), and WVP (1.09 (g m-1 s-1 Pa-1) 1011) properties contained garlic oil extracted at the central point (55 °C and 1:2). Thermal analysis indicated increased melting temperatures in films with added oil, suggesting low thermal degradation. These results suggest that garlic oil addition can improve the properties of fish gelatin-based films, making them promising for biodegradable packaging.

Statistical evaluation of measured biomechanical properties of human brain aneurysm samples.

Background and purpose:

Human brain aneurysms may often prove fatal if not re­cognized in time and treated accordingly. The understanding of development and rupture of aneurysms can significantly be improved by the application of numerical modelling, which in turn, requires the knowledge of mechanical properties of vessel wall. This study aims to identify assumed differences with respect to age, sex, spatial orientation, and rupture by utilizing detailed statistical analysis of uniaxial tensile measurements of human brain aneurysm samples, performed by the authors in a previous project.

At surgery of 42 patients, aneu­rysm fundi were cut distally to the clip. In each case, depending on size, varying number of stripes (altogether 88) were prepared and uniaxial stress-strain measurements were performed. Quantities related to the capacity, energy absorption or stiffness were determined and statistically analysed.

The number of specimens in the aneurysm sample was sufficient to establish statistical differences with respect to sex and rupture (p<0.05). No significant differences were detected in orientation, though higher values of stresses and deformations were ob­tained in the circumferential direction com­pared to the meridional direction. 

Significant differences bet­ween sexes with respect to ultimate deformations were demonstrated according to expectation, and the hypothesis on equality of energy capacity could be supported. Similarity of curves with respect to specimen orientation was also observed and ruptured aneurysm sacs tended to be smaller in size. It seems that differences and trends described in this paper are realistic and need to be applied in numerical modelling.

Numerical investigation of fluid flow behavior in steel cord with lattice Boltzmann methodology: The impacts of microstructure and loading force.

Steel cord materials were found to have internal porous microstructures and complex fluid flow properties. However, current studies have rarely reported the transport behavior of steel cord materials from a microscopic viewpoint. The computed tomography (CT) scanning technology and lattice Boltzmann method (LBM) were used in this study to reconstruct and compare the real three-dimensional (3D) pore structures and fluid flow in the original and tensile (by loading 800 N force) steel cord samples. The pore-scale LBM results showed that fluid velocities increased as displacement differential pressure increased in both the original and tensile steel cord samples, but with two different critical values of 3.3273 Pa and 2.6122 Pa, respectively. The original steel cord sample had higher maximal and average seepage velocities at the 1/2 sections of 3D construction images than the tensile steel cord sample. These phenomena should be attributed to the fact that when the original steel cord sample was stretched, its porosity decreased, pore radius increased, flow channel connectivity improved, and thus flow velocity increased. Moreover, when the internal porosity of tensile steel cord sample was increased by 1 time, lead the maximum velocity to increase by 1.52 times, and the average velocity was increased by 1.66 times. Furthermore, when the density range was determined to be 0-38, the pore phase showed the best consistency with the segmentation area. Depending on the Zou-He Boundary and Regularized Boundary, the relative error of simulated average velocities was only 0.2602 percent.

Strain rate-dependent failure mechanics of the intervertebral disc under tension/compression and constitutive analysis.

BACKGROUND: The intervertebral disc exhibits not only strain rate dependence (viscoelasticity), but also significant asymmetry under tensile and compressive loads, which is of great significance for understanding the mechanism of lumbar disc injury under physiological loads. OBJECTIVE: In this study, the strain rate sensitive and tension-compression asymmetry of the intervertebral disc were analyzed by experiments and constitutive equation. METHOD: The Sheep intervertebral disc samples were divided into three groups, in order to test the strain rate sensitive mechanical behavior, and the internal displacement as well as pressure distribution. RESULTS: The tensile stiffness is one order of magnitude smaller than the compression stiffness, and the logarithm of the elastic modulus is approximately linear with the logarithm of the strain rate, showing obvious tension-compression asymmetry and rate-related characteristics. In addition, the sensitivity to the strain rate is the same under these two loading conditions. The stress-strain curves of unloading and loading usually do not coincide, and form a Mullins effect hysteresis loop. The radial displacement distribution is opposite between the anterior and posterior region, which is consistent with the stress distribution. By introducing the damage factor into ZWT constitutive equation, the rate-dependent viscoelastic and weakening behavior of the intervertebral disc can be well described.

Tensile strength of adhesives in peripheral nerve anastomoses: an in vitro biomechanical evaluation of four different neurorrhaphies.

BACKGROUND: The fundamental prerequisite for prognostically favorable postoperative results of peripheral nerve repair is stable neurorrhaphy without interruption and gap formation. METHODS: This study evaluates 60 neurorrhaphies on femoral chicken nerves in terms of the procedure and the biomechanical properties. Sutured neurorrhaphies (n = 15) served as control and three sutureless adhesive-based nerve repair techniques: Fibrin glue (n = 15), Histoacryl glue (n = 15), and the novel polyurethane adhesive VIVO (n = 15). Tensile and elongation tests of neurorrhaphies were performed on a tensile testing machine at a displacement rate of 20 mm/min until failure. The maximum tensile force and elongation were recorded. RESULTS: All adhesive-based neurorrhaphies were significant faster in preparation compared to sutured anastomoses (p < 0.001). Neurorrhaphies by sutured (102.8 [cN]; p < 0.001), Histoacryl (91.5 [cN]; p < 0.001) and VIVO (45.47 [cN]; p < 0.05) withstood significant higher longitudinal tensile forces compared to fibrin glue (10.55 [cN]). VIVO, with △L/L0 of 6.96 [%], showed significantly higher elongation (p < 0.001) compared to neurorrhaphy using fibrin glue. CONCLUSION: Within the limitations of an in vitro study the adhesive-based neurorrhaphy technique with VIVO and Histoacryl have the biomechanical potential to offer alternatives to sutured neuroanastomosis because of their stability, and faster handling. Further in vivo studies are required to evaluate functional outcomes and confirm safety.

Physicomechanical, morphological and tribo-deformation characteristics of lightweight WC/AZ31B Mg-matrix biocomposites for hip joint applications.

Exploring high strength materials with a higher concentration of reinforcements in the alloy proves to be a challenging task. This research has explored magnesium-based composites (AZ31B alloy) with tungsten carbide reinforcements, enhancing strength for medical joint replacements via league championship optimisation. The primary objective is to enhance medical joint replacement biomaterials employing magnesium-based composites, emphasising the AZ31B alloy with tungsten carbide reinforcements. The stir casting method is utilised in the manufacture of magnesium matrix composites (MMCs), including varied percentages of tungsten carbide (WC). The mechanical characteristics, such as micro-hardness, tensile strength, and yield strength, have been assessed and compared with computational simulations. The wear studies have been carried out to analyse the tribological behaviour of the composites. Additionally, this study investigates the prediction of stress and the distribution of forces inside bone and joint structures, therefore offering significant contributions to the field of biomedical research. This research contemplates the use of magnesium-based MMCs for the discovery of biomaterials suitable for medical joint replacement. The study focuses on the magnesium alloy AZ31B, with particles ranging in size from 40 to 60 microns used as the matrix material. Moreover, the outcomes have revealed that when combined with MMCs based on AZ31B-magnesium matrix, the WC particle emerges as highly effective reinforcements for the fabrication of lightweight, high-strength biomedical composites. This study uses the league championship optimisation (LCO) approach to identify critical variables impacting the synthesis of Mg MMCs from an AZ31B-based magnesium alloy. The scanning electron microscopy (SEM) images are meticulously analysed to depict the dispersion of WC particulates and the interface among the magnesium (Mg) matrix and WC reinforcement. The SEM analysis has explored the mechanisms underlying particle pull-out, the characteristics of inter-particle zones, and the influence of the AZ31B matrix on the enhancement of the mechanical characteristics of the composites. The application of finite element analysis (FEA) is being used in order to make predictions regarding the distribution of stress and the interactions of forces within the model of the hip joint. This study has compared the physico-mechanical and tribological characteristics of WC to distinct combinations of 0%, 5%, 10% and 15%, and its impact on the performance improvements. SEM analysis has confirmed the findings' improved strength and hardness, particularly when 10%-15% of WC was incorporated. Following the incorporation of 10% of WC particles within Mg-alloy matrix, the outcomes of the study has exhibited enhanced strength and hardness, which furthermore has been evident by utilising SEM analysis. Using ANSYS, structural deformation and stress levels are predicted, along with strength characteristics such as additional hardness of 71 HRC, tensile strength of 140-150 MPa, and yield strength closer to 100-110 MPa. The simulations yield significant insights into the behaviour of the joint under various loading conditions, thus enhancing the study's significance in biomedical environments.

Biomechanical testing of ex vivo porcine tendons following high intensity focused ultrasound thermal ablation.

INTRODUCTION: Magnetic resonance-guided focused ultrasound (MRgFUS) has been demonstrated to be able to thermally ablate tendons with the aim to non-invasively disrupt tendon contractures in the clinical setting. However, the biomechanical changes of tendons permitting this disrupting is poorly understood. We aim to obtain a dose-dependent biomechanical response of tendons following magnetic resonance-guided focused ultrasound (MRgFUS) thermal ablation. METHODS: Ex vivo porcine tendons (n = 72) were embedded in an agar phantom and randomly assigned to 12 groups based on MRgFUS treatment. The treatment time was 10, 20, or 30s, and the applied acoustic power was 25, 50, 75, or 100W. Following each MRgFUS treatment, tendons underwent biomechanical tensile testing on an Instron machine, which calculated stress-strain curves during tendon elongation. Rupture rate, maximum treatment temperature, Young's modulus and ultimate strength were analyzed for each treatment energy. RESULTS: The study revealed a dose-dependent response, with tendons rupturing in over 50% of cases when energy delivery exceeded 1000J and 100% disruption at energy levels beyond 2000J. The achieved temperatures during MRgFUS were directly proportional to energy delivery. The highest recorded temperature was 56.8°C ± 9.34 (3000J), while the lowest recorded temperate was 18.6°C ± 0.6 (control). The Young's modulus was highest in the control group (47.3 MPa ± 6.5) and lowest in the 3000J group (13.2 MPa ± 5.9). There was no statistically significant difference in ultimate strength between treatment groups. CONCLUSION: This study establishes crucial thresholds for reliable and repeatable disruption of tendons, laying the groundwork for future in vivo optimization. The findings prompt further exploration of MRgFUS as a non-invasive modality for tendon disruption, offering hope for improved outcomes in patients with musculotendinous contractures.

Transdermal Delivery of Niacin Through Polysaccharide Films Ameliorates Cutaneous Flushing in Experimental Wistar Rats.

BACKGROUND: Niacin, an established therapeutic for dyslipidemia, is hindered by its propensity to induce significant cutaneous flushing when administered orally in its unmodified state, thereby constraining its clinical utility. OBJECTIVE: This study aimed to fabricate, characterize, and assess the in-vitro and in-vivo effectiveness of niacin-loaded polymeric films (NLPFs) comprised of carboxymethyl tamarind seed polysaccharide. The primary objective was to mitigate the flushing-related side effects associated with oral niacin administration. METHODS: NLPFs were synthesized using the solvent casting method and subsequently subjected to characterization, including assessments of tensile strength, moisture uptake, thickness, and folding endurance. Surface characteristics were analyzed using a surface profiler and scanning electron microscopy (SEM). Potential interactions between niacin and the polysaccharide core were investigated through X-ray diffraction experiments (XRD) and Fourier transform infrared spectroscopy (FTIR). The viscoelastic properties of the films were explored using a Rheometer. In-vitro assessments included drug release studies, swelling behavior assays, and antioxidant assays. In-vivo efficacy was evaluated through skin permeation assays, skin irritation assays, and histopathological analyses. RESULTS: NLPFs exhibited a smooth texture with favorable tensile strength and moisture absorption capabilities. Niacin demonstrated interaction with the polysaccharide core, rendering the films amorphous. The films displayed slow and sustained drug release, exceptional antioxidant properties, optimal swelling behavior, and viscoelastic characteristics. Furthermore, the films exhibited biocompatibility and non-toxicity towards skin cells. CONCLUSION: NLPFs emerged as promising carrier systems for the therapeutic transdermal delivery of niacin, effectively mitigating its flushing-associated adverse effects.

Effect of low power Er:YAG laser irradiation of CAD-CAM resin-based composites on resin bonding.

PURPOSE: To investigate the effect of painless low-power Er:YAG laser irradiation of conventional and polymer-infiltrated ceramic network (PICN) type CAD-CAM resin-based composites (RBCs) on resin bonding. METHODS: An Er:YAG laser system, phosphoric acid etchant, universal adhesive, RBC, and two types of CAD-CAM RBC block were used. Microtensile bond strength, fracture mode, scanning electron microscopy (SEM) observations of bonding interfaces and CAD-CAM surfaces, and surface roughness of ground and pretreated surfaces were investigated. As pretreatment methods, low-power Er:YAG laser irradiation and air-abrasion with alumina particles were used. RESULTS: The effect of low-power Er:YAG laser irradiation of CAD-CAM RBCs on bonding to repair resin varied depending on the type of CAD-CAM RBCs. CLINICAL SIGNIFICANCE: The low-power Er:YAG laser irradiation of the conventional CAD-CAM RBCs was shown to be effective as a surface pretreatment for resin bonding, while the laser irradiation of PICN-type CAD-CAM RBCs was not effective.

Development of Biocompatible Electrospun PHBV-PLLA Polymeric Bilayer Composite Membranes for Skin Tissue Engineering Applications.

Bilayer electrospun fibers aimed to be used for skin tissue engineering applications were fabricated for enhanced cell attachment and proliferation. Different ratios of PHBV-PLLA (70:30, 80:20, and 90:10 w/w) blends were electrospun on previously formed electrospun PHBV membranes to produce their bilayers. The fabricated electrospun membranes were characterized with FTIR, which conformed to the characteristic peaks assigned for both PHBV and PLLA. The surface morphology was evaluated using SEM analysis that showed random fibers with porous morphology. The fiber diameter and pore size were measured in the range of 0.7 ± 0.1 µm and 1.9 ± 0.2 µm, respectively. The tensile properties of the bilayers were determined using an electrodynamic testing system. Bilayers had higher elongation at break (44.45%) compared to the monolayers (28.41%) and improved ultimate tensile strength (7.940 MPa) compared to the PHBV monolayer (2.450 MPa). In vitro cytotoxicity of each of the scaffolds was determined via culturing MC3T3 (pre-osteoblastic cell line) on the membranes. Proliferation was evaluated using the Alamar Blue assay on days 3, 7, and 14, respectively. SEM images of cells cultured on membranes were taken in addition to bright field imaging to visually show cell attachment. Fluorescent nuclear staining performed with DAPI was imaged with an inverted fluorescent microscope. The fabricated bilayer shows high mechanical strength as well as biocompatibility with good cell proliferation and cell attachment, showing potential for skin substitute applications.

PEG-crosslinked O-carboxymethyl chitosan films with degradability and antibacterial activity for food packaging.

This study developed a kind of PEG-crosslinked O-carboxymethyl chitosan (O-CMC-PEG) with various PEG content for food packaging. The crosslinking agent of isocyanate-terminated PEG was firstly synthesized by a simple condensation reaction between PEG and excess diisocyanate, then the crosslink between O-carboxymethyl chitosan (O-CMC) and crosslinking agent occurred under mild conditions to produce O-CMC-PEG with a crosslinked structure linked by urea bonds. FT-IR and 1H NMR techniques were utilized to confirm the chemical structures of the crosslinking agent and O-CMC-PEGs. Extensive research was conducted to investigate the impact of the PEG content (or crosslinking degree) on the physicochemical characteristics of the casted O-CMC-PEG films. The results illuminated that crosslinking and components compatibility could improve their tensile features and water vapor barrier performance, while high PEG content played the inverse effects due to the microphase separation between PEG and O-CMC segments. The in vitro degradation rate and water sensitivity primarily depended on the crosslinking degree in comparison with the PEG content. Furthermore, caused by the remaining -NH2 groups of O-CMC, the films demonstrated antibacterial activity against Escherichia coli and Staphylococcus aureus. When the PEG content was 6% (medium crosslinking degree), the prepared O-CMC-PEG-6% film possessed optimal tensile features, high water resistance, appropriate degradation rate, low water vapor transmission rate and fine broad-spectrum antibacterial capacity, manifesting a great potential for application in food packaging to extend the shelf life.

In vivo study on the repair of rat Achilles tendon injury treated with non-thermal atmospheric-pressure helium microplasma jet.

Non-thermal atmospheric-pressure plasma (NTAPP) has been widely studied for clinical applications, e.g., disinfection, wound healing, cancer therapy, hemostasis, and bone regeneration. It is being revealed that the physical and chemical actions of plasma have enabled these clinical applications. Based on our previous report regarding plasma-stimulated bone regeneration, this study focused on Achilles tendon repair by NTAPP. This is the first study to reveal that exposure to NTAPP can accelerate Achilles tendon repair using a well-established Achilles tendon injury rat model. Histological evaluation using the Stoll's and histological scores showed a significant improvement at 2 and 4 weeks, with type I collagen content being substantial at the early time point of 2 weeks post-surgery. Notably, the replacement of type III collagen with type I collagen occurred more frequently in the plasma-treated groups at the early stage of repair. Tensile strength test results showed that the maximum breaking strength in the plasma-treated group at two weeks was significantly higher than that in the untreated group. Overall, our results indicate that a single event of NTAPP treatment during the surgery can contribute to an early recovery of an injured tendon.

Interface stress transfer model and modulus parameter equivalence method for composite materials embedded with tensile pre-strain shape memory alloy fibers.

The constitutive model and modulus parameter equivalence of shape memory alloy composites (SMAC) serve as the foundation for the structural dynamic modeling of composite materials, which has a direct impact on the dynamic characteristics and modeling accuracy of SMAC. This article proposes a homogenization method for SMA composites considering interfacial phases, models the interface stress transfer of three-phase cylinders physically, and derives the axial and shear stresses of SMA fiber phase, interfacial phase, and matrix phase mathematically. The homogenization method and stress expression were then used to determine the macroscopic effective modulus of SMAC as well as the stress characteristics of the fiber phase and interface phase of SMA. The findings demonstrate the significance of volume fraction and tensile pre-strain in stress transfer between the fiber phase and interface phase at high temperatures. The maximum axial stress in the fiber phase is 705.05 MPa when the SMA is fully austenitic and the pre-strain increases to 5%. At 10% volume fraction of SMA, the fiber phase's maximum axial stress can reach 1000 MPa. Ultimately, an experimental verification of the theoretical calculation method's accuracy for the effective modulus of SMAC lays the groundwork for the dynamic modeling of SMAC structures.

Mechanical behavior of full-thickness burn human skin is rate-independent.

Skin tissue is recognized to exhibit rate-dependent mechanical behavior under various loading conditions. Here, we report that the full-thickness burn human skin exhibits rate-independent behavior under uniaxial tensile loading conditions. Mechanical properties, namely, ultimate tensile stress, ultimate tensile strain, and toughness, and parameters of Veronda-Westmann hyperelastic material law were assessed via uniaxial tensile tests. Univariate hypothesis testing yielded no significant difference (p > 0.01) in the distributions of these properties for skin samples loaded at three different rates of 0.3 mm/s, 2 mm/s, and 8 mm/s. Multivariate multiclass classification, employing a logistic regression model, failed to effectively discriminate samples loaded at the aforementioned rates, with a classification accuracy of only 40%. The median values for ultimate tensile stress, ultimate tensile strain, and toughness are computed as 1.73 MPa, 1.69, and 1.38 MPa, respectively. The findings of this study hold considerable significance for the refinement of burn care training protocols and treatment planning, shedding new light on the unique, rate-independent behavior of burn skin.

Highly Stretchable Double Network Ionogels for Monitoring Physiological Signals and Detecting Sign Language.

At the heart of the non-implantable electronic revolution lies ionogels, which are remarkably conductive, thermally stable, and even antimicrobial materials. Yet, their potential has been hindered by poor mechanical properties. Herein, a double network (DN) ionogel crafted from 1-Ethyl-3-methylimidazolium chloride ([Emim]Cl), acrylamide (AM), and polyvinyl alcohol (PVA) was constructed. Tensile strength, fracture elongation, and conductivity can be adjusted across a wide range, enabling researchers to fabricate the material to meet specific needs. With adjustable mechanical properties, such as tensile strength (0.06-5.30 MPa) and fracture elongation (363-1373%), this ionogel possesses both robustness and flexibility. This ionogel exhibits a bi-modal response to temperature and strain, making it an ideal candidate for strain sensor applications. It also functions as a flexible strain sensor that can detect physiological signals in real time, opening doors to personalized health monitoring and disease management. Moreover, these gels' ability to decode the intricate movements of sign language paves the way for improved communication accessibility for the deaf and hard-of-hearing community. This DN ionogel lays the foundation for a future in which e-skins and wearable sensors will seamlessly integrate into our lives, revolutionizing healthcare, human-machine interaction, and beyond.

The Influence of Various Crosslinking Conditions of EDC/NHS on the Properties of Fish Collagen Film.

The process of crosslinking improves the physicochemical properties of biopolymer-based composites, making them valuable for biomedical applications. EDC/NHS-crosslinked collagen materials have a significant potential for tissue engineering applications, due to their enhanced properties and biocompatibility. Chemical crosslinking of samples can be carried out in several ways, which is crucial and has a direct effect on the final properties of the obtained material. In this study, the effect of crosslinking conditions on the properties of collagen films using EDC and NHS was investigated. Studies included FTIR spectroscopy, AFM, swelling and degradation tests, mechanical testing and contact angle measurements. Evaluation of prepared collagen films indicated that both crosslinking agents and crosslinking conditions influenced film properties. Notable alternations were observed in the infrared spectrum of the sample, to which EDC was added directly to the fish collagen solution. The same sample indicated the lowest Young modulus, tensile strength and breaking force parameters and the highest elongation at break. All samples reached the maximum swelling degree two hours after immersion in PBS solution; however, the immersion-crosslinked samples exhibited a significantly lower degree of swelling and were highly durable. The highest roughness was observed for the collagen film crosslinked with EDC, whereas the lowest was observed for the specimen crosslinked with EDC with NHS addition. The crosslinking agents increased the surface roughness of the collagen film, except for the sample modified with the addition of EDC and NHS mixture. All films were characterized by hydrophilic character. The films' modification resulted in a decrease in their hydrophilicity and wettability. Our research allows for a comparison of proposed EDC/NHS crosslinking conditions and their influence on the physicochemical properties of fish collagen thin films. EDC and NHS are promising crosslinking agents for the modification of fish collagen used in biomedical applications.

The Effects of Reusing Cobalt-Chromium Alloy Powder on Its Mechanical Properties and Grain Size: An In Vitro Study.

PURPOSE: To characterize material changes that may occur in virgin cobalt-chromium (Co-Cr) alloy powder when it is blended with alloy powders that have been reused multiple times. MATERIALS AND METHODS: Initially, 20 kg of virgin Co-Cr powder was loaded into a laser-sintering device. The tensile test specimens were fabricated in the first (Group 1), fourth (Group 2), seventh (Group 3), tenth (Group 4), and thirteenth (Group 5) production cycles (N = 15). Prior to fabricating the specimens, powder alloy samples were collected from the powder bed for analysis. The tensile strength, elastic modulus, and percent elongation were calculated with tensile testing. Scanning electron microscopy and energy dispersive x-ray spectroscopy (SEM/EDS) and laser particle size distribution (LPSD) were used to analyze the alloy powder samples. The fracture surface of one tensile test specimen from each group was examined via SEM/EDS. One-way ANOVA followed by Dunnett T3 test was used for statistical analysis (α = .05). RESULTS: No difference was observed between groups in terms of tensile strength. A statistically significant difference was observed between Groups 1 and 2 in terms of percent elongation. Groups 2 and 4 were statistically significantly different in terms of both elastic modulus and percent elongation (P ≤ .05). SEM images of the powder alloy showed noticeable differences with increasing numbers of cycles. SEM images and the EDS analysis of the fractured specimens were in accordance with the strength data. CONCLUSIONS: Reusing Co-Cr alloy powder increased the particle size distribution. However, there was no correlation between increased cycle number and the mechanical properties of the powder.

Fine extraction of cellulose from corn straw and the application for eco-friendly packaging films enhanced with polyvinyl alcohol.

Biomass materials substituting for petroleum-based polymers occupy an important position in achieving sustainable development. Cellulose, a typical biomass material, stands out as the primary choice for producing eco-friendly packaging materials. However, it is still a challenge to efficiently utilize cellulose from waste biomass materials in practice. Herein, cellulose-based films were prepared by pretreating waste corn straw, separating straw husk, straw pith and straw leaf, and extracting cellulose through alkali and sodium chlorite treatment to improve its mechanical properties using the cross-linked polyvinyl alcohol (PVA) method in this work. The prepared composite films were characterized by Fourier transform infrared spectrometer (FTIR), X-ray diffraction instrument (XRD), Scanning electron microscopy (SEM), Thermogravimetric (TG) and mechanical properties. The results indicated that corn straw husk exhibited the highest cellulose content of 31.67 wt%, and obtained husk cellulose had the highest crystallinity of 52.5 %. Compared to corn straw, the crystallinity of husk cellulose, pith cellulose and leaf cellulose increased by 19.5 %, 16.4 % and 44.1 %, respectively. Husk cellulose/PVA composite films were the most thermally stable, with a maximum weight loss temperature of 346.8 °C. In addition, the husk cellulose/PVA composite film had the best tensile strength of 37 MPa. Meanwhile, the composite films had good UV shielding, low water vapor transmission rate and biodegradability. Therefore, this work provides a fine utilization route of waste corn straw, and as-prepared cellulose based films have potential application in eco-friendly packaging materials.

A novel biopolymeric composite edible film based on sunnhemp protein isolate and potato starch incorporated with clove oil: Fabrication, characterization, and amino acid composition.

Composite edible films were developed by casting method using sunnhemp protein isolate (SHPI) and potato starch (PS) at various proportions (100:0, 90:10, 80:20; 70:30, 60:40, and 50:50) containing glycerol as a plasticizer and clove oil. All the edible films were evaluated for thickness, moisture content, solubility, swelling ratio, water activity. Further characterization of edible films was done on the basis of mechanical, optical, thermal and structural attributes along with morphology. Among all the films, composite film containing 50 % SHPI, 50 % PS and 1 % clove oil were having better characteristics. The solubility and WVP decreased, while the tensile strength and elongation at break of composite film increased with the inclusion of potato starch and clove oil. Intermolecular interactions in the composite film matrix were confirmed by FTIR and XRD analysis. SEM images confirmed the structural compactness and integrity of all the developed films. The amino acid composition of edible films indicated presence of most of the essential amino acids. The present finding of this research work shows that the utilization of sunnhemp protein in the development of biocomposite edible films represents an alternative opportunity of sustainable edible food packaging.