Bulk Modulus Research Articles

Collagen silver-doped hydroxyapatite scaffolds reinforced with 3D printed frameworks for infection prevention and enhanced repair of load-bearing bone defects

Osteomyelitis, a severe bone infection, is an extremely challenging complication in the repair of traumatic bone defects. Furthermore, the use of long-term high-dose antibiotics in standard treatment increases the risks of antibiotic resistance. Herein, an antibiotic-free, collagen silver-doped hydroxyapatite (coll-AgHA) scaffold reinforced with a 3D printed polycaprolactone (PCL) framework was developed with enhanced mechanical properties to be used in the repair of load-bearing defects with antimicrobial properties as a preventative measure against osteomyelitis. The AgHA particles were fabricated in varying Ag doses and loaded within freeze-dried collagen scaffolds at two concentrations. The optimised Ag dose (1.5 mol% Ag) and AgHA concentration (200 wt%) within the collagen scaffold demonstratedin vitroosteogenic and antibacterial properties againstS. aureus (S. aureus),the main causative pathogen of osteomyelitis. The addition of the PCL framework to the coll-AgHA scaffolds significantly enhanced the compressive modulus from 4 to 12 MPa while maintaining high porosity as well as both pro-osteogenic and antibacterial properties. The reinforced coll-AgHA scaffolds were implantedin vivoand demonstrated enhanced bone repair, significantly greater vessel formation, and calcified tissue in a load-bearing critical sized defect in rats. Taken together, these results confirm the capacity of this novel biomaterial scaffold as a preventative measure against infection in bone repair for use in load-bearing defects, without the use of antibiotics.

Mechanical and Durable Performance of Lime-Steel Slag-Coal Gangue Mixtures Prepared by a Uniform Design Method for Pavement Base Applications

To reduce the accumulation of coal gangue and steel slag, a mixture of lime-steel slag-coal gangue for pavement base was prepared. Six groups of lime-steel slag-coal gangue mixtures were designed using a uniform design method. The 7 d unconfined compressive strength, 180 d compressive resilience modulus and 180 d splitting tensile strength tests, the freeze-thaw cycles, and the wet and dry cycles were carried out to study the mechanical properties, frost resistance and water stability. The expansion effect of f-CaO in steel slag on the mixtures was investigated by water immersion. SEM was used to explore microscopic changes in the mixtures. The field application of coal gangue mixture was carried out for two years. The results show that the regression equations obtained by the uniform test have high accuracy. With the increase of lime in the mixture, the mechanical strength, frost resistance, and water stability of the mixtures were first enhanced and then decreased. With the increase of steel slag, the unconfined compressive strength increased, the compressive resilience modulus increased at first and then decreased, the splitting tensile strength decreased, the BDR value decreased, and the strength loss of water stability increased gradually. The internal structure of the mixtures is stable and has good frost resistance. There is no obvious microscopical difference before and after freeze-thaw cycles. The immersion expansion rate of the mixtures was far less than 1.5 %.

First-Principles Study of Mechanical Properties of Pb(ZrxTi1−x)O3 in the Cubic and Tetragonal Phase

In this study, we employed the first-principles method based on density functional theory to calculate the elastic constants, bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, and density of states for both cubic and tetragonal phases of Pb(ZrxTi1−x)O3. The structural model of Pb(ZrxTi1−x)O3 was established using the virtual crystal approximation (VCA). Our results demonstrate that the VCA-calculated properties are in excellent agreement with other theoretical predictions and experimental data. As the Zr content increases, the lattice constants of both cubic and tetragonal Pb(ZrxTi1−x)O3 increase, while the c/a ratio initially decreases and subsequently increases. Both cubic and tetragonal Pb(ZrxTi1−x)O3 satisfy the Born stability criteria, indicating mechanical stability. For the cubic phase, the elastic constants, bulk modulus, and shear modulus decrease with increasing Zr content. In contrast, for the tetragonal phase, the elastic and shear moduli exhibit a non-monotonic trend, peaking at a Zr content of 0.5, where Pb(Zr0.5Ti0.5)O3 demonstrates superior mechanical properties. A comparative analysis reveals that as Zr content increases, the cubic phase exhibits enhanced structural resilience, greater electronic structure stability, and increased anisotropy. These characteristics make cubic Pb(ZrxTi1−x)O3 more suitable for advanced manufacturing techniques such as additive manufacturing, offering enhanced design flexibility for ferroelectric materials.

Mechanical properties of double-solid waste cement stabilized Macadam

Cement stabilized macadam base has high strength and excellent bearing capacity, but the problems of water-temperature sensitivity, easy shrinkage cracking and large demand for aggregate limit the further development and application of cement stabilized macadam base. At the same time, with the economy development, the increase of solid waste, such as waste tires and construction waste, has caused great pressure on the ecological environment. In order to ensure better mechanical properties and shrinkage resistance of the cement stabilized macadam on the basis of full use of solid waste. In this paper, mechanical properties tests such as unconfined compressive strength, splitting strength, compressive resilient modulus and shrinkage properties tests such as dry shrinkage and temperature shrinkage were conducted. Double-solid waste cement stabilized macadam mixture were prepared by partially replace fine and coarse aggregates with waste crumb rubber of different mesh and replacement ratios and recycled concrete aggregate of different replacement ratios, and their properties were investigated. The experimental results show that: (1) The good elasticity and toughness of waste crumb rubber can improve the crack resistance of cement stabilized macadam mixture. While the mechanical properties such as unconfined compressive strength and splitting strength will be reduced. (2) The mechanical properties of double-solid waste cement stabilized macadam mixture can be improved by partially replacing coarse aggregate with appropriate amount of recycled concrete aggregate with porous and rough surface, but it will adversely affect its shrinkage resistance. (3) The recommended particle size and replacement ratio of waste crumb rubber in double-solid waste cement stabilized macadam mixture are 40 mesh and 0.5%, respectively, and the recommended replacement ratio of recycled concrete aggregate is 75%. The mechanical properties indexes of double-solid waste cement stabilized macadam mixture can meet the specification requirements.

Resin Composite Depth of Cure Through Transparent Matrix Materials Used for Injection Molding.

The purpose of this study was to compare the curing light transmittance and depth of cure (DOC) of resin composite through clear polyvinyl siloxane (PVS) impression materials and 3D printed clear matrix materials at various thicknesses. Cylindrical specimens (n=6) of three clear PVS materials (Affinity Crystal, Clear Bite Matrix, Exaclear) were fabricated in Teflon molds, and two 3D-printed clear matrix materials (Filtek matrix, IDB 2) were printed into specimens of five different thicknesses (2 mm, 4 mm, 6 mm, 8 mm, 10 mm). To measure light irradiance transmittance, specimens were placed on a radiometer (CheckUp), allowing the transmitted irradiance from a light-curing unit (Elipar DeepCure-S, 1450 mW/cm2) to be recorded. DOC of resin composite specimens was measured by placing flowable composite (PVS and IDB 2) or heated conventional composite (Filtek Matrix) into a split metal die with a 4 mm diameter opening. The composite was cured through the different matrix specimens using the Elipar DeepCure-S curing light for the manufacturer's recommended curing time (10 seconds) or double the curing time (20 seconds). The DOC of the composite specimens was measured according to ISO 4049 7.8, and the percentage of total cure (%TC) was calculated by dividing by the total cure (DOC with no matrix and 10-second cure). The correlation between irradiance transmittance and %TC was analyzed with Pearson's coefficient. For each matrix material, the %TC was compared to the total cure of the material using a Dunnett's test. The compressive modulus of each material was measured and compared with a one-way ANOVA. There was a statistically significant, strong positive correlation between irradiance transmittance and %TC for 10 seconds (r=0.90 p<0.001) and 20 seconds (r=0.89 p<0.001). There was not a statistically different DOC for the total cure with Affinity (2 mm), Clear Bite (2 mm), Exaclear (2, 4, 6 mm), IDB2 (2, 4, 6, 8 mm), and Filtek Matrix (2,4 mm) if a 20-second cure was used. Decreased light irradiance from curing through clear matrix materials decreases the DOC of resin composites. Doubling the curing time when curing through some matrix materials at certain thicknesses allowed a total cure.

Synthesis and Characterization of Metakaolin–Wollastonite Geopolymer Foams for Removal of Heavy Metal Ions from Water

Over the past few decades, researchers have focused on developing new compositions and preparation techniques for geopolymers, as multifunctional products, to optimize their characteristics for use in multiple applications. Therefore, this paper investigates metakaolin geopolymer foam and introduces new geopolymer foams based on hybrid metakaolin and wollastonite mineral precursors for water purification. The geopolymer foams were prepared using an alkaline activator, mineral-based powders (wollastonite and metakaolin), a foaming agent (aluminum powder), and a foam stabilizer (olive oil). In addition to mechanical tests and assessments of the adsorption capacity of heavy metal ions, the geopolymer foams were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The geopolymer foams exhibited unique pore structures, containing four classes of pore networks with diameters around 1000 µm, 25 µm, 3 µm, and a well-arranged mesopore network of 50 nm. The utilization of wollastonite (CaSiO3) alongside metakaolin as a hybrid precursor led to fundamental changes in the composition of the geopolymer binders: a new crystal phase, Ca5(SiO4)2(OH)2, was formed, and the Si-Al-Na crystal phase disappeared, which led to an increase in the amorphous phase from 87% to 92%. The adsorption rate of heavy metal ions, namely Cr, Co, Cu, Zn, Pd, and As, increased upon introducing wollastonite as a precursor, with absorption rates ranging from 11% to 68%. The findings also revealed that wollastonite significantly increased the geopolymers foams’ compressive strength and elastic modulus from 30 KPa to 67 KPa and from 31 MPa to 126 MPa, respectively.

Predicted thermodynamic structural and elastic properties of SrCuP and SrCuSb for thermoelectric applications

The Pseudopotential method coupled with plane waves implemented in the quantum espresso code was used in the prediction of the structural parameters and elastic constants of SrCuX (X = P, Sb) materials. The obtained results of lattice parameters and bulk modulus at equilibrium agree well with their experimental and theoretical data cited in the literature. The calculated Young’s modulus of SrCuX (X = P, Sb) aggregate thermoelectric materials are 109.25 GPa and 78.22 GPa, while their Debye temperatures are 364.2 K and 261.8 K. The vibration energy of phonons is 24.14 kJ/mol and 23.37 kJ/mol for SrCuP and SrCuSb. Our thermodynamic parameters increase monotonically with temperatures for both SrCuP and SrCuSb materials. To the best of our knowledge, there are no data available in the literature on the elastic and thermodynamic parameters of SrCuX (X = P, Sb) compounds, then our results are prediction. The absence of virtual phonon frequencies indicates high dynamic stability in both materials, with a band gap about 1 THz between optical and acoustic phonons in SrCuP and SrCuSb.

Ab initio investigation on the effect of solid solution RE on interface and mechanical properties of Al–Mg–Si alloy

Investigating the role of solid-solution rare earth elements (REs) in Al–Mg–Si alloys helps to gain a deeper understanding of the mechanisms of solid-solution elements, enabling the adjustment of alloy composition to improve the microstructure and overall performance of the alloy. This study employs first-principles computational methods to reveal the impact of rare earth element addition on the interface properties of α-Al/β″–Mg5Si6 and α-Al/β–Mg2Si in Al–Mg–Si alloys, as well as the effects on the mechanical properties of β″ and β precipitate phases. The study first constructs two interface models, Al(130)/Mg5Si6(100) and Al(001)/Mg2Si(001), to analyze their interface properties. Based on this, the substitution positions of rare earth elements in the interface models after their addition are further discussed. The results indicate that the atomic substitution positions of rare earth elements are related to crystal structure, interface properties, rare earth atomic radius, and electronegativity. Interface property studies show that the addition of rare earth elements significantly enhances the adhesion of Al(130)/Mg5Si6(100) and Al(001)/Mg2Si(001) interfaces, reduces interface energy, and strengthens interface stability. Additionally, the effects of rare earth element addition on the lattice mismatch of Al(130)/Mg5Si6(100) and Al(001)/Mg2Si(001) interfaces exhibit opposite trends and, to some extent, inhibit the β″ → β phase transformation. Mechanical property studies of the precipitate phases reveal that rare earth atoms in solid solution in β″ and β phases decrease the bulk modulus, shear modulus, and Young modulus, while increasing the Poisson ratio and B/G ratio. This indicates that the introduction of solid-solution rare earth elements reduces the alloy's stiffness and shear resistance while enhancing its plasticity and brittleness.

Poly(2-alkyl-2-oxazoline) Hydrogels as Synthetic Matrices for Multicellular Spheroid and Intestinal Organoid Cultures.

The extracellular matrix (ECM) plays a crucial role in organoid cultures by supporting cell proliferation and differentiation. A key feature of the ECM is its mechanical influence on the surrounding cells, directly affecting their behavior. Matrigel, the most commonly used ECM, is limited by its animal-derived origin, batch variability, and uncontrollable mechanical properties, restricting its use in 3D cell-model-based mechanobiological studies. Poly(2-alkyl-2-oxazoline) (PAOx) synthetic hydrogels represent an appealing alternative because of their reproducibility and versatile chemistry, enabling tuning of hydrogel stiffness and functionalization. Here, we studied PAOx hydrogels with differing compressive moduli for their potential to support 3D cell growth. PAOx hydrogels support spheroid and organoid growth over several days without the addition of ECM components. Furthermore, we discovered intestinal organoid epithelial polarity reversion in PAOx hydrogels and demonstrate how the tunable mechanical properties of PAOx can be used to study effects on the morphology and oxygenation of live multicellular spheroids.

In situ swelling of low-friction, high load-bearing self-bending bilayer hydrogels inspired by articular cartilage

The articular cartilage is characterized by its gradient hierarchical structure, which exhibits excellent lubrication and robust load-bearing properties. However, its inherent difficulty in self-repair after damage presents numerous formidable challenges for cartilage repair. Inspired by the unique structure of articular cartilage, a biomimetic bilayer hydrogel composed of PAM (polyacrylamide) and PAM/SA (sodium alginate) is prepared using a two-stepin-situswelling method. The bilayer hydrogel demonstrates exceptional structural stability due to the interlayerin-situchemical cross-linking. Compared to monolayer hydrogels, the PAM-PAM/SA bilayer hydrogel demonstrates superior mechanical attributes, exhibiting a compressive strength of 1 MPa and a compressive modulus of 0.22 MPa. Furthermore, exploration of the tribological performance of the PAM-PAM/SA bilayer hydrogel have revealed its low-friction performance under high loads, with a coefficient of friction as low as 0.032. Finally, leveraging the differential swelling properties between the distinct layers of the PAM-PAM/SA bilayer hydrogel, a self-bending biomimetic cartilage capable of conforming to complex joint surfaces is fabricated. This highly lubricating, mechanically robust, and conformal biomimetic cartilage provides an effective means for addressing cartilage defects and joint diseases.

Evaluation and optimization of physical, mechanical, and biological characteristics of 3D printed Whitlockite/calcium silicate composite scaffold for bone tissue regeneration using response surface methodology.

Calcium phosphate-based bioscaffolds are used for bone tissue regeneration because of their physical and chemical resemblance to human bone. Calcium, phosphate, sodium, potassium, magnesium, and silicon are important components of human bone. The successful biomimicking of human bone characteristics involves incorporating all the human bone elements into the scaffold material. In this work, Mg-Whitlockite (WH) and Calcium Silicate (CS) were selected as matrix and reinforcement respectively, because of their desirable elemental composition and regenerative properties. The magnesium in WH increases mineralization in bone, and the silicon ions in CS support vascularization. The Mg-WH was synthesized using the wet chemical method, and powder characterization tests were performed. Response surface methodology (RSM) is used to design the experiments with a combination of material compositions, infill ratios (IFs), and sintering temperatures (STs). The WH/CS bioceramic composite is 3D printed in three different compositions: 100/0, 75/25, and 50/50 wt%, with IFs of 50%, 75%, and 100%. The physical and mechanical characterization study of printed samples is conducted and the result is optimized using RSM. ANOVA (Analysis of Variance) is used to establish the relationship between input parameters and responses. The optimized input parameters were the WH/CS composition of 50/50 wt%, IF of 50%, and ST of 1150 °C, which bring out the best possible combination of physical and mechanical characteristics. The RSM optimized response was a density of 2.27 g cm-3, porosity of 36.74%, wettability of 45.79%, shrinkage of 25.13%, compressive strength of 12 MPa, and compressive modulus of 208.49 MPa with 92% desirability. The biological characterization studies were conducted for the scaffold samples prepared with optimized input parameters. The biological studies confirmed the capabilities of the WH/CS composite scaffolds in bone regenerative applications.

Elastic Anisotropy and Thermal Properties of Sr2ZrMoO6 Double Perovskite under Different Pressure

This study investigates the elastic and thermal properties of the double perovskite Sr2ZrMoO6 under different pressures from 0 to 80 GPa using first‐principles calculations within the generalized gradient approximation of density functional theory. The calculated second‐order elastic constants confirm the mechanical stability of the compound up to 80 GPa. The material exhibits significant elastic anisotropy, with elastic constants C11, C33, and C44 showing distinct pressure‐dependent behavior. The elastic properties, including bulk modulus, shear modulus, Young's modulus, and Poisson's ratio, all increase with a rise in pressure, which enhances the material's stiffness and rigidity, improving its resistance to deformation or fracture. The Pugh ratio greater than 0.57, a negative Cauchy constant, and a low Poisson's ratio suggest that the material remains brittle within the examined pressure range. The calculated tolerance factor and formation energy confirm its thermodynamic stability. The minimum thermal conductivity of the material increases slightly with pressure across all directions, maintaining the anisotropic order &gt; &gt; , indicating improved phonon transport under compression. The specific heat capacity increases with pressure at low temperatures and approaches the Dulong–Petit limit at higher temperatures. These findings suggest Sr2ZrMoO6 holds potential for high‐performance optical waveguides and optoelectronic applications.

A Study on the Use of Necuron-Type Polymer Plastics utilized for Sliding Bearing Manufacturing

This paper presents research on the characteristics of the thermoplastic materials used in the manufacture of sliding bearings. Two types of materials from the category of thermosetting polyurethanes with the commercial names Necuron 1050 and Necuron 1300 were investigated. Tests were conducted to determine their physical and mechanical characteristics, such as density, hardness, tensile strength, compressive strength, and longitudinal modulus of elasticity. The results obtained during the study attest to the quality of the materials in the thermosetting polyurethane category in terms of hardness, tear resistance, and compression resistance. The materials in the category of thermosetting polyurethanes stand out as the right choice for applications that require mechanical strength, durability, and resistance to environmental factors.

An extended thermal pressure equation of state for sodium fluoride.

The effect of pressure and temperature on the unit-cell volume of NaF has been measured by X-ray powder diffraction at ambient pressure between 12 and 300 K and neutron powder diffraction up to 5 GPa between 140 and 350 K. These data have been combined with high-pressure volume data at 300 and 950 K to 25 GPa and adiabatic bulk modulus data to 650 K to define an equation of state for NaF relating molar volume to both temperature and pressure. The model combines a fourth-order Birch-Murnaghan equation of state at 295 K with a Mie-Grüneisen-Debye model for thermal pressure. The parameters of the model set at 295 K and ambient pressure are as follows: reference unit-cell volume V 0 = 14.9724 (5) cm3 mol-1, isothermal bulk modulus K 0T = 46.79 (14) GPa, first derivative of the bulk modulus K'0T = 5.72 (12), second derivative of the bulk modulus K''0T = -0.43 (4) GPa-1, Debye temperature T MGD = 459 (3) K, and Anderson Grüneisen parameters γ0 = 1.547 (11) and q = 0.94 (18).

ASUGNN: an asymmetric-unit-based graph neural network for crystal property prediction

Material properties can often be derived directly from fundamental equations governing electron behavior. In this study, we present an open-source asymmetric-unit-based graph neural network designed to capture atomic patterns and their corresponding electron distributions. By coarse-graining sites belonging to conjugate subgroups and analyzing reciprocal space through powder X-ray diffraction patterns, our model predicts key physical properties, including formation energy, band gap, bulk modulus and metal/non-metal classification. Our method demonstrates exceptional predictive accuracy for properties calculated using density functional theory across the Materials Project dataset. Our approach is compared with state-of-the-art models and exhibits impressively low error rates in zero-shot predictions.

An oxidative metal ions-free lignin-catalyzed multifunctional hydrogel bioelectronics for codable eye communication

To meet the stringent requirements of wearable and flexible electronics for functionality and comfort, it is urgent to develop green conductive, self-adhesive, and stretchable functional hydrogels. The chelates of transition metal ions and lignosulfonate sodium (LS) can impart multi-functionality to the hydrogel and significantly improve the hydrogel’s gelation speed. However, the presence of metal ions may weaken the adhesiveness of hydrogels by shielding the functional adhesive groups. Here, an oxidative metal ions-free lignin-catalyzed multifunctional polyacrylic acid (PAA) hydrogel is proposed. LS itself can undergo a redox reaction with the initiator to generate many free radicals, thereby catalyzing the rapid polymerization of polymer monomers at room temperature and subsequent gelation. Furthermore, LS can easily improve the hydrogels’ softness (compressive modulus: ∼7 kPa) and stretchability (maximum ∼2700 %). Interestingly, LS can simultaneously promote the hydrogel’s conductivity, adhesion, and UV blocking. Notably, the hydrogel integrating these advantageous features is suitable as non-invasive electronics in the human epidermis. We explored its ability to act as adhesive bioelectrodes to collect electrooculographic signals in patients with physical and language impairments. Bioelectrodes can recognize the patient’s eye movements. The displayed electrical signal can be output in 6 languages after being encoded. This provides a valuable case for LS-doped functional hydrogels in the medical field.

First-principles, magnetothermal and magnetocaloric calculations on Gd1-xCexMn2Ge2 ([formula omitted])

In this research, we study the two compounds, Gd0.5Ce0.5Mn2Ge2 and Gd0.33Ce0.67Mn2Ge2, employing the molecular field theory and the first-principles calculations. The electronic and elastic characteristics are determined through the use of Density Functional Theory (DFT) calculations. Super-cell DFT computations are utilized to calculate the overall density of states (DOS), elastic stiffness constants Cij, and various elastic properties e.g. bulk and shear moduli. The primary objective is to investigate important physical properties such as magnetization, magnetic heat capacity, and key aspects of the magnetocaloric effect including both isothermal magnetic entropy change ΔSm and adiabatic temperature change ΔTad., relative cooling power (RCP), and magnetic phase transition. We investigate these characteristics in magnetic fields up to 6 T and at temperatures up to 400 K. The two compounds show a Curie temperature TC around 340 K. We also studied the effect of high magnetic fields on the nature of the phase transition.

Performance and carbon emission of solid waste-based solidification materials cooperative fiber solidifying soil

The mechanical and drying shrinkage characteristics of solid waste-based solidification materials (SBM) cooperative fiber solidifying soil were examined. The microstructure was tested using scanning electron microscopy and mercury intrusion porosimetry. The results revealed that the optimum content for both polyvinyl alcohol (PVA) and basalt fiber (BF) was both 0.3%. The uncontrolled compressive strength and deformation modulus (E50) of SBM incorporating PVA were enhanced by 36% and 107%, respectively. At 28 days of curing, the dry shrinkage of solidified soil recycled aggregate showed a reduction of 70%, reaching 300 με. The presence of abundant ettringite (Aft) in SBM solidified soil acted as shrinkage compensatory. The formation of calcium silicate hydrates (CSH) and Aft on the damaged PVA surface suggests that the bonding effect of PVA with the matrix is superior to that of BF. The porosity of SBM solidified soil was diminished to 27%, with the pores shifting toward smaller sizes. The carbon emission and carbon emissions relative to the performance of SBM were 186 kg/t and 50.3 kg/MPa, respectively.

Investigation of the behaviour of tunable chalcogenide-Bismuth based perovskite BiTl (SxSe1-x)3(X = 0, 0.33, 0.67, 1): first principles calculations

Density functional theory (DFT) driven by the quantum ESPRESSO code was used in this study to investigate the structural, opto-electronic, and thermoelectric properties of ternary perovskite chalcogenide compound. This is to examine their possible use in optoelectronics and reducing the dependency on silicon and fossil fuel. The Perovskite compounds crystalize in the cubic phase with a space group Pm-3m. The volume versus energy is fitted by the Birch-Murnaghan equation of state which yielded the equilibrium lattice constant of 8.353, 8.488, 8.629 and 8.806, bulk modulus of 255.8, 242.7, 233.5 and 222.4, for BiTlS3 , BiTlS2 Se1 , BiTlS1 Se2 and BiTlSe3 . Indirect band gaps of 2.6 eV, 2.7 eV, 2.9 eV, and 3.2 eV were obtained for BiTlS3 , BiTlS2 Se1 , BiTlS1 Se2 and BiTlSe3 compounds, respectively. Also, increment in the energy from 0 eV to 10 eV resulted in optical properties fluctuation within 0 cm-1 to 1.5 × 109 cm-1 for absorption coefficient in the compounds. However, a variation from 10 eV to 20 eV moved the absorption coefficient to 4.2 × 109 cm-1 for all the compounds from visible to the UV range. Furthermore, the observed properties show that the value of figure of merit obtained is 0.125 for BiTlS3 , 0.100 for BiTlS2 Se1 , 0.068 for BiTlS1 Se2 and 0.055 for BiTlSe3 at 300 K. By adjusting the chalcogen ratio, BiTlX3 (X = S, Se) possess the tunable band gap in the whole visible light range, which is of great significance for the development of new-type, high-efficient semiconductor material and optoelectronic devices, while the low thermoelectric values predict the compounds use as sensors. The proposed results may pave the way for further investigations into the use of the perovskite compounds for optoelectronic devices.

Digital light processing printing of non-modified protein-only compositions.

This study explores the utilization of digital light processing (DLP) printing to fabricate complex structures using native gelatin as the sole structural component for applications in biological implants. Unlike approaches relying on synthetic materials or chemically modified biopolymers, this research harnesses the inherent properties of gelatin to create biocompatible structures. The printing process is based on a crosslinking mechanism using a di-tyrosine formation initiated by visible light irradiation. Formulations containing gelatin were found to be printable at the maximum documented concentration of 30wt%, thus allowing the fabrication of overhanging objects and open embedded. Cell adhesion and growth onto and within the gelatin-based 3D constructs were evaluated by examining two implant fabrication techniques: (1) cell seeding onto the printed scaffold and (2) printing compositions that contain cells (cell-laden). The preliminary biological experiments indicate that both the cell-seeding and cell-laden strategies enable making 3D cultures of chondrocytes within the gelatin constructs. The mechanical properties of the gelatin scaffolds have a compressive modulus akin to soft tissues, thus enabling the growth and proliferation of cells, and later degrade as the cells differentiate and form a grown cartilage. This study underscores the potential of utilizing non-modified protein-only bioinks in DLP printing to produce intricate 3D objects with high fidelity, paving the way for advancements in regenerative tissue engineering.