Irregular Porous Structure Research Articles

Design and preparation of biomimetic "Hard-soft" functional scaffold with gradient irregular pore structure for bone repair

To treat critical-sized defects in long bones, a novel structure was proposed by introducing a Haversian biomimetic structure and trabecular-like irregular pore morphology (IPM) structure into functional gradient porous scaffolds (FGPS). The outer shell structure is a "hard" structure providing mechanical support, and the inner core is a "soft" structure with radial gradient distribution IPM structure to promote the ingrowth of bone tissue. In this study, different inner core continuous gradient FGPS (GIPM) and layered FGPS (IPM, and BCC structure), with different outer shell pore sizes (300, 500, and 700 μm) were designed and fabricated by selective laser melting. The results show the stiffness of those FGPS was between 20.0-28.7 kN/mm, which is similar to the native femur (with a stiffness ranging from 7.2-11.7 kN/mm) of similar size. The GIPM-500 has more uniform stress distribution and stress transfer, resulting in superior load-bearing efficiency. Moreover, GIPM-500 exhibited excellent fatigue durability, achieving excellent fatigue cycles of more than 1×106 cycles. Cell immunofluorescence shows that the GIPM-500 and IPM-500 are more suitable for cell attachment and growth due to the flexibility of the local porosity and curvature. Bone defect repair simulations showed that GIPM-500 can meet normal load-bearing requirements while having little impact on the normal stress-strain trajectory. This work provides a novel biomimetic scaffold design containing both cortical and trabecular bone components for repairing critical-size defects in long bones.

Pore-scale study of coupled heat and mass transfer during primary freeze-drying using an irregular pore network model

This study presents a pore network (PN) model with transient heat transfer and quasi-steady transitional vapor transport that is for the first time applied to irregular porous structures that are obtained by reconstruction of X-ray tomography image data. In contrast to previous studies, the irregular pores are not approximated by spheres but implemented in their original shape. Secondly, instead of assuming cylindrical throats as pore connections, the actual distance between pore centers as well as the pore cross sections are used for the computation of the vapor transport coefficient. The control volume elements of the computational model are matched with the cells obtained by Voronoi tessellation. The improvements have clear advantages over former approaches where the reconstructed void space is usually strongly simplified by balls and sticks confined in a regular lattice structure. A freeze-dried sample of maltodextrin DE12 with 20% (w/w) solid content is used for benchmarking the new methodology. Its morphological and thermal properties are determined by the novel PN model. The simulation results of primary freeze-drying (FD) are compared to reference cases in two ways. First, the differences in heat and mass transfer kinetics as compared to regular PNs are emphasized. Secondly, the PN simulation results are confronted with a simple literature model that neglects pore size distribution (PSD) and transient heat transfer. It is shown that already in small domains with relatively narrow PSD, the variation of the mass transfer coefficient affects the computed sublimation fluxes and yields a significant deviation from the simpler literature model. Moreover, it is revealed in this study that the structure has a significant impact on the sublimation front temperature. This is demonstrated by the comparison of FD in the irregular PN to a regular PN with almost identical PSD but different porosity. The development, verification, and benchmarking of the new PN model can be seen as an important step for studies of the structure dependence of FD.

Variation in oxidative potential of fine particulate matter and its association with chemical constituents at a regional site in India

Fine particulate matter (PM2.5) constituents are greatly affected by site-specific emission sources and are one of the main reasons for oxidative stress that leads to cardiovascular ailments. This study investigated the temporal, seasonal, and episodic variations in the oxidative potential (OP) of PM2.5 and its association with chemical components. Additionally, we have also examined the effect of filter substrates on OP. Dithiothreitol (DTT) and ascorbic acid (AA) acellular assays were used to estimate the formation of reactive oxygen species (ROS) in PM2.5 samples collected over a year from a regional site in India. PM2.5 morphology and functional groups were also analyzed. Results showed that OPDTTv was at the highest in winter (2.56 ± 0.84 nmol min−1 m−3) and at the lowest during monsoon (0.79 ± 0.65 nmol min−1 m−3). OPAAv exhibited the highest activity in post-monsoon (0.09 ± 0.04 nmol min−1 m−3) and least in summer (0.05 ± 0.04 nmol min−1 m−3). Biomass burning (BB) and open-field burning of crop residue during the rabi and kharif harvesting seasons were associated with significantly elevated PM2.5 toxicity, which is indicative of the contribution of combustion-derived particles. OPDTTv and OPAAv levels from BB in post-monsoon were 21 % and 67 % higher than the levels observed during BB in summer. Flaky irregular agglomerates and porous structures were observed during the BB period. Fourier-transformed infrared spectroscopy revealed that traffic-emitted organic hydrocarbons CH functional group was dominant across the season. Further, chemical species such as organics (OC and EC fractions) and ions (SO42−, NH4+, Cl−, NO3−) were found to be significantly associated with OP. Among the three filter substrates, the Teflon showed higher OP variability for both assays. This study emphasizes the impact of regional toxic aerosols across seasons and during episodic events. It contributes to our understanding of the toxicity of ambient PM2.5, which is crucial for developing targeted air-quality management strategies.

Magnetic porous functional material from coal mine waste for simultaneous removal of cadmium and arsenic in water and soil: Synergistic effect of iron-containing minerals and porous structure

Heavy metals such as cadmium and arsenic (Cd/As) can cause harmful effects on human health. Coal mine waste (coal gangue) is a solid waste residue without commercial values produced abundantly in the coalfield. Hence, treating Cd and As concurrently with reutilizing coal gangue (CG) is critical to ecologically sustainable growth. This work successfully synthesized the magnetic porous functional materials (MPCG) based on CG using a two-step method for the simultaneous removal of Cd and As in water and soil. First, MPCG exhibited an irregular network porous structure. Then, it consisted of iron (Fe), mainly in magnetite, hematite, and pyrite forms. Such properties also exhibited excellent pH adaptability and coadsorption capacity by removing up to 103.79 mg g−1 and 579.43 mg g−1 for Cd(II) and As(V), respectively. There is a synergistic effect between the iron-containing minerals and porous structure to enhance the adsorption capacity of MPCG for Cd(Ⅱ) and As(Ⅴ). Several primary potential adsorption mechanisms by MPCG for Cd(Ⅱ) and As(Ⅴ) were identified. The potential mechanisms of Cd(II) adsorption mainly include ion exchange, electrostatic attraction, surface complexation and precipitation/co-precipitation, and the potential mechanisms of As(V) adsorption mainly include electrostatic attraction, surface complexation and precipitation. In addition, the removal rates of MPCG for Cd and As in soil were as high as 44.78 and 38.44 %, respectively. In conclusion, MPCG has excellent potential as an efficient and environmentally compatible functional material, which provides a potential way to realize efficient heavy metal removal from our ecosystems.

Constructing a monolithic amino-functionalized poly(ether sulfone) loose nanofiltration membrane for efficient dye/salt fractionation

Loose nanofiltration (LNF) is a promising new technique for dye/salt separation, but LNF membranes still suffer from low permeance and inadequate selectivity. In this study, novel monolithic amino-functionalized poly(ether sulfone) (PES) LNF membranes were developed in three steps, PES powder-grafted with polyacrylonitrile (PAN) under gamma-ray irradiation and membrane preparation via non-solvent-induced phase separation, followed by an amination process. The resultant aminated PES LNF membrane with tetraethylenepentamine (APES-TP) had a thinner skin layer and unusual irregular vesicle-like pore structure in its sublayer compared with the original PES substrate. The amination process increased the hydrophilicity of the APES-TP membranes and partially neutralized the surface zeta-potential. The permeation test confirmed that the APES-TP membrane exhibited 100 % NaCl permeation together with high levels of pure water permeance (77.9 L m–2h−1 bar−1) and dye rejection (98.5 % for Congo red, 97.1 % for Nair blue, and 97.6 % for methyl blue). Even when paired with simulated industrial wastewater containing multiple direct dyes and inorganic salts (1 g L–1 dye and 5 g L–1 salts), the APES-TP membrane still rejected 99.4 % of the mixed dyes, proving its practical applicability to treating industrial dye wastewater. Furthermore, the APES-TP membrane exhibited excellent endurance to harsh conditions (such as acidic, alkaline, and oxidative) and exceptional recyclability (97.9 % permeance recovery rate). This study bridges the gap between conventional nonsolvent phase inversion and the emerging LNF membrane fabrication technology, allowing the LNF technique to be used to fractionate organic matters with salts in batch mode.

Metal-ion-binding properties of glycyrrhiza polysaccharide extracted from Licorice: Structural characterization and potential application in drug delivery

Licorice is not only a widely used food, but also a classic tonic Chinese medicine, which mainly contains glycyrrhiza polysaccharides (GP) and flavonoids with excellent anti-inflammatory and antioxidant pharmacological activities. In this study, a neutral homogeneous polysaccharide (GP1–2) was isolated from Glycyrrhiza uralensis Fisch. However, its gelation behavior and properties have yet to be comprehensively studied. In this study, a Ca2+ cross-linked physical hydrogel based on neutral GP1–2 (GP1–2-Ca2+) is fabricated. The ability of metal ions to cross-linked gelation with GP1–2 is explored with respect to the polysaccharide concentrations, ion species, and pH environments. The pH range of Ca2+ cross-linked with GP1–2 to form hydrogel is 8 to 10, and the gelation concentration ranges from 20.0 % to 50.0 % w/v. Subsequently, the properties of the GP1–2-Ca2+ hydrogels are investigated using rheological measurements, scanning electron microscopy, free radical scavenging, MTT assays, healing capability, and enzyme-linked immunosorbent assays. The results reveal that the structure of GP1–2 presents an irregular porous structure, however, the physical gel formed after cross-linking with Ca2+ microscopically showed a globular porous structure with uniform distribution, suggesting that this structure characteristic may be used as a carrier material for drug delivery. Meanwhile, the GP1–2-Ca2+ hydrogel also possessed extraordinary viscoelasticity, cytocompatibility, antioxidant properties, anti-inflammatory activity, and ability to promote wound healing. Furthermore, the potential of GP1–2-Ca2+ hydrogels as drug delivery materials was validated by using rhein as a model drug for encapsulation, it is demonstrated that its cumulative release behavior of GP1–2-Ca2+ is pH-dependent. All in all, this study reveals the potential application of natural polysaccharides in drug delivery, highlighting its dual roles as carrier materials and bioactive ingredients.

Potential of wood fiber/polylactic acid composite microperforated panel for sound absorption application in indoor environment

This study introduces a novel approach using wood fiber/PLA composite microperforated panel (WFCMPP) for indoor sound absorption purposes. WFCMPP, comprising rubber tree chip-derived fibers and a polylactic acid (PLA) matrix, with the dimensions of the rubber tree chip-derived fibers ranging from 0.5 to 1 mm, demonstrated promising sound absorption coefficients comparable to other natural fiber composite microperforated panels. The maximum sound absorption coefficient was recorded at 0.989 with a resonance frequency of 1416 Hz when the wood fiber composition was 30 %. The study also investigates the impact of wood fiber composition on sound absorption, revealing a linear relationship between fiber content and both porosity and sound absorption. The peak sound absorption coefficient of WFCMPP remained almost identical at different air gap thicknesses, showcasing the versatility and effectiveness of the samples. Additionally, the performance remained robust even with variations in air gap size. Scanning electron microscope analysis confirms the irregular porous structure and complexity contributing to enhanced sound absorption. WFCMPP presents a sustainable and effective alternative for acoustic applications, combining sound absorption performance with environmental considerations.

Sorting microparticle mixtures by multiple properties in a single dielectrophoretic filter

The sorting of nano- and microparticles according to different properties is an industrially highly relevant but partly unsolved problem. In this study, we investigate the sorting of a complex microparticle mixture on the basis of their different properties by insulator-based dielectrophoretic filtration at high throughput. We demonstrate here that such a high selectivity demanding sorting process is possible in a single device thanks to recent advances in the development of dielectrophoretic filters, which has been shown using simple binary mixtures in a previous study. In that study, a filter with a regular structure (mesh) is introduced with pores several orders of magnitude larger than the target particles so that the particles are trapped solely by the action of positive dielectrophoresis. In this work, we demonstrate the improvement of the filter design, by comparing the trapping behavior to an alternative, irregular porous ceramic structure as a filter medium. A significantly higher selectivity for positive dielectrophoresis could be reached using the regular mesh structure. This high selectivity enables a stepwise operation mode, combining a selective trapping step and several subsequent selective remobilization steps. A mixture of polystyrene-based particles could be sorted by size, shape, and surface coating in one pass of the filter. The proposed method is therefore a promising technique to efficiently create highly specific particle systems in the future.

Engineered loose nanofiltration membrane for efficient dye/salt separation by starting from poly(ether sulfone) powder modification

Loose nanofiltration (LNF) is increasingly considered as the powerful technique for dye desalination due to its clear advantages at energy efficiency, selectivity and low pollution. But the membrane materials for loose nanofiltration process still suffer from the low permeance, unsatisfactory selectivity, membrane fouling and high cost. Herein, we propose a new three-step route to fabricate efficient poly(ether sulfone) (PES) LNF membrane, which starts from PES powder modification via mutual radiation-induced grafting polymerization and ensues immersion precipitation phase inversion and amination processes. The obtained PES-based LNF membrane possessed a thinner skin layer and an unusual irregular vesicular pore structure in sublayer instead of the finger-like macrovoids of conventional PES membrane. Thus, it achieved larger filtration permeance (35.5 L m–2 h−1 bar−1), high dye rejection (93.7 % to Congo Red) but low salt rejection (2.9 % to NaCl) during the filtration process of Congo red-containing saline water. It also showed excellent separation stability at high operation pressure and tolerance to acidic, alkaline and chlorine-oxidative conditions. Therefore, such a three-step strategy could endow the PES membrane with both loose and thinner skin layer in a reliable and scalable way, enlightening the development of high-performance LNF membrane for wastewater treatment and resource recovery.

A Rapid, Efficient Method for Anodic Aluminum Oxide Membrane Room-Temperature Multi-Detachment from Commercial 1050 Aluminum Alloy.

For commercial processes, through-hole AAO membranes are fabricated from high-purity aluminum by chemical etching. However, this method has the disadvantages of using heavy-metal solutions, creating large amounts of material waste, and leading to an irregular pore structure. Through-hole porous alumina membrane fabrication has been widely investigated due to applications in filters, nanomaterial synthesis, and surface-enhanced Raman scattering. There are several means to obtain freestanding through-hole AAO membranes, but a fast, low-cost, and repetitive process to create complete, high-quality membranes has not yet been established. Here, we propose a rapid and efficient method for the multi-detachment of an AAO membrane at room temperature by integrating the one-time potentiostatic (OTP) method and two-step electrochemical polishing. Economical commercial AA1050 was used instead of traditional high-cost high-purity aluminum for AAO membrane fabrication at 25 °C. The OTP method, which is a single-step process, was applied to achieve a high-quality membrane with unimodal pore distribution and diameters between 35 and 40 nm, maintaining a high consistency over five repetitions. To repeatedly detach the AAO membrane, two-step electrochemical polishing was developed to minimize damage on the AA1050 substrate caused by membrane separation. The mechanism for creating AAO membranes using the OTP method can be divided into three major components, including the Joule heating effect, the dissolution of the barrier layer, and stress effects. The stress is attributed to two factors: bubble formation and the difference in the coefficient of thermal expansion between the AAO membrane and the Al substrate. This highly efficient AAO membrane detachment method will facilitate the rapid production and applications of AAO films.

Characterization and fractal characteristics of nano-scale pore structure in shale gas reservoirs: a case study of the deep Longmaxi Formation, Zigong region, Southern Sichuan Basin, China

Taking the Longmaxi deep-marine shale gas reservoir in Zigong region as the research target, this paper aimed to characterize the nano-scale pore structure and investigate the reservoirs’ heterogeneity based on fractal theory. By conducting a series of experimental studies, mainly including TOC, XRD, gas adsorption (N2 and CH4), we were able to clarify the main controlling factors for the heterogeneity of deep shale pore structure. Our results indicated that the deep marine shale possessed a significant amount of organic matter, as the average TOC value is 3.68%. The XRD analysis results show that quartz and clay were the main mineral types, and the total content of these two minerals averaged 77.5%. Positive correlations were observed between TOC and quartz, while TOC decreases as the clay mineral increases, this discovery indicating that quartz is biogenic. Based on FHH (Frenkele-Halseye-Hill) method, by using the LTNA adsorption isotherms, we took relative pressure P/P0=0.5 as the boundary, then two separate fractal dimension were deduced, D1 and D2 represent the fractal characteristics of small and large pores, respectively. Our study revealed that both D1 and D2 demonstrated positive correlations with N2 adsorption pore volume and adsorption specific surface area, while negatively correlated with the adsorption average pore diameter. Moreover, the two fractal dimensions showed positive associations with TOC and quartz and negative associations with clay. Additionally, D1 and D2 also demonstrated a positive correlation with Langmuir volume. The presence of micropores was found to significantly influence the formation of an irregular pore structure in shale. As the pore size decreased, the adsorption specific surface area increased, resulting in a more intricate pore structure, and the fractal dimension of the pores elevated, ultimately. This intricate structure is beneficial for the accumulation of shale gas. These research findings offer valuable insights for the comprehensive assessment of deep shale gas, and enrich our knowledge of enrichment mechanisms in deep shale gas reservoirs.

Hydrothermal synthesis of αILiVOPO4 as a cathode material for Li-ion batteries

This paper presents the synthesis of a novel cathode material, αI-LiVOPO4, featuring a porous multilayered lamellar structure, achieved through the hydrothermal method. Initially, αI-LiVOPO4·2 H2O was synthesized by maintaining a reaction kettle at 160 °C for 40 h. Subsequently, the parent compound underwent dehydration at various temperatures for 2 h to yield αI-LiVOPO4. The dehydration process was investigated through thermogravimetric analysis. Analysis via powder X-ray diffraction confirmed the crystallization of the product into the αI-LiVOPO4 phase. TEM and EDS analyses revealed an irregular porous structure with uniform distribution of elements. The electrochemical performance of αI-LiVOPO4 was evaluated through constant current charge-discharge tests within a voltage range of 3–4.5 V. Results demonstrated an initial capacity of 106.9 mAh·g–1 at 0.05 C, with a capacity retention of 100.9 mAh·g–1 after the 50th cycle. Additionally, cyclic voltammetry indicated favorable cycling performance and minimal polarization at elevated voltages.

Nano-engineered versatile Janus natural-skin with sandwich structure for wearable all-season personal thermal management

Thermal management wearables hold significant promise for various applications, such as bio-integrated electronics, multifunctional fabrics, thermoelectric devices, etc. Given the complex and volatile external environmental conditions they may encounter, thermal management wearables should possess versatile and comprehensive auxiliary functions to enable cutting-edge advanced applications. Herein, we present a multifunctional nano-engineered Janus-type natural-skin (SHRC-skin) offering dual-modes of solar heating and radiative cooling. Additionally, the SHRC-skin integrated functionalities like flammability resistance, electromagnetic interference (EMI) shielding, and physiological signal monitoring achieved through the integration of traditional spray techniques and a phase-conversion pathway on natural-skin as a substrate, SHRC-skin enabled all-season thermal management. The radiative cooling side of the SHRC-skin incorporates a CA/Mg11(HPO3)8(OH)6 composite coating with an irregular porous structure, while the solar heating side consists of multi-walled carbon nanotubes (MWCNT) with a rough structure. The radiative cooling layer exhibited a solar reflectance of ∼90.13 % and a mid-infrared emittance of ∼87.6 %, whereas the heating layer demonstrated a solar absorptance of ∼89 %. These attributes translated to excellent thermal management performance in outdoor-tests. Furthermore, SHRC-skin offered extensive additional functionalities, including exceptional asymmetric wetting, flame retardancy, electrical conductivity, Joule heating, electromagnetic shielding, and physiological signal monitoring. This versatility significantly enhances SHRC-skin's adaptability to complex and diverse environments. In summary, the multifunctional SHRC-skin seamlessly transitions between cooling and heating modes without additional energy input. This innovation holds great promise for all-season wearable thermal management, environmentally friendly travel, and energy-efficient building furnishings, and opens new possibilities for the development of wearable materials across various scenarios.

Effect of sintering on stress distribution of thermal barrier coatings for high temperature blade

In the process of long-term high temperature service, thermal barrier coatings (TBCs) will inevitably be sintered, leading to pores healing and porosity decline, which will affect the microstructure and the stability of mechanical properties of TBCs. To understand the relationship between the microstructural changes of sintered TBCs and the mechanical properties, in this work, the cross-sectional microstructure of TBCs at different sintering times were investigated by scanning electron microscopy (SEM). After calculating the porosity and pore size distribution, two-dimensional (2D) numerical models were developed for five different porosities (16 %–12 %) by an improved reconstruction method with layer-by-layer labeling. Based on the results of finite element (FE) analysis after thermal cycling, it was found that the coating's irregular pore structures lead to stress concentration, which affects the mechanical properties of the coating to a great extent. For the whole TC layer, the level of stresses increases and the absolute value of maximum stress augments significantly by 46 % associated with the doubled increase of stress concentration areas with the densification of coating. For the local areas of TC layer, the changes in pore morphology led to a more complex variation in local stress fields. At the TC/BC interface, the Mises stress level tends to increase with decreasing porosity during sintering. At the TC surface, coatings with lower porosities cause higher stresses near this region. The insights gained from the numerical results contribute to a better understanding of the failure behavior of real TBCs systems and help to further remedy the deficiencies and difficulties of the experimental work.

Biomimetic design and clinical application of Ti-6Al-4V lattice hemipelvis prosthesis for pelvic reconstruction

ObjectiveThis study aims to biomimetic design a new 3D-printed lattice hemipelvis prosthesis and evaluate its clinical efficiency for pelvic reconstruction following tumor resection, focusing on feasibility, osseointegration, and patient outcomes.MethodsFrom May 2020 to October 2021, twelve patients with pelvic tumors underwent tumor resection and subsequently received 3D-printed lattice hemipelvis prostheses for pelvic reconstruction. The prosthesis was strategically incorporated with lattice structures and solid to optimize mechanical performance and osseointegration. The pore size and porosity were analyzed. Patient outcomes were assessed through a combination of clinical and radiological evaluations.ResultsMultiple pore sizes were observed in irregular porous structures, with a wide distribution range (approximately 300–900 μm). The average follow-up of 34.7 months, ranging 26 from to 43 months. One patient with Ewing sarcoma died of pulmonary metastasis 33 months after surgery while others were alive at the last follow-up. Postoperative radiographs showed that the prosthesis’s position was consistent with the preoperative planning. T-SMART images showed that the host bone was in close and tight contact with the prosthesis with no gaps at the interface. The average MSTS score was 21 at the last follow-up, ranging from 18 to 24. There was no complication requiring revision surgery or removal of the 3D-printed hemipelvis prosthesis, such as infection, screw breakage, and prosthesis loosening.ConclusionThe newly designed 3D-printed lattice hemipelvis prosthesis created multiple pore sizes with a wide distribution range and resulted in good osteointegration and favorable limb function.

Production and characterization of novel marine black yeast’s exopolysaccharide with potential antiradical and anticancer prospects

The marine black yeasts are characterized by the production of many novel protective substances. These compounds increase their physiological adaptation to multi-extreme environmental stress. Hence, the exopolysaccharide (EPS) producing marine black yeast SAHE was isolated in this study. It was molecularly identified as Hortaea werneckii (identity 98.5%) through ITS1 and ITS4 gene sequencing analysis. The physicochemical properties of the novel SAHE-EPS were investigated through FTIR, GC-MS, TGA, ESM, and EDX analysis, revealing its heteropolysaccharide nature. SAHE-EPS was found to be thermostable and mainly consists of sucrose, maltose, cellobiose, lactose, and galactose. Furthermore, it exhibited an amorphous texture and irregular porous surface structure. SAHE-EPS showed significant antiradical activity, as demonstrated by the DPPH radical scavenging assay, and the IC50 was recorded to be 984.9 μg/mL. In addition, SAHE-EPS exhibited outstanding anticancer activity toward the A549 human lung cancer cell line (IC50 = 22.9 μg/mL). Conversely, it demonstrates minimal cytotoxicity toward the WI-38 normal lung cell line (IC50 = 203 μg/mL), which implies its safety. This study represents the initial attempt to isolate and characterize the chemical properties of an EPS produced by the marine black yeast H. werneckii as a promising antiradical and anticancer agent.

Study on the Degradation Effect of Tetracycline Using a Co-Catalyst Loaded on Red Mud

Red mud was modified by impregnation with Co element loading. The Co-RM catalyst was characterized using scanning electron microscopy (SEM), X-ray powder diffraction (XRD), X-ray fluorescence (XRF), and UV full-band scanning. The results showed that the modified Co-RM catalyst successfully loaded the Co element and formed an irregular pore structure on the surface, thereby increasing the number of active sites of the red mud catalyst and effectively improving the degradation efficiency of tetracycline. Under the optimal conditions of a catalyst dosage of 0.3 g/L, a persulfate dosage of 3 g/L, a reaction temperature of 50 °C, and a pH value of 7, a removal rate of 50 mg/L of tetracycline can be achieved: 89.5% after 90 min. The effects of common anions and humic acids in water, as well as radical quenchers (anhydrous ethanol and tert-butanol), on the degradation of tetracycline were investigated. The results showed that Cl−, CO32−, HCO3−, H2PO4−, NO32−, HPO42−, and humic acids showed inhibitory effects on the degradation of tetracycline, while SO42− showed a promoting effect on the degradation of tetracycline. The free radical quenching experiment showed that the most important free radicals that can degrade tetracycline in the system are sulfate radicals.

Forming quality analysis of TC4 titanium alloy based on SLM orthogonal process

The TC4 titanium alloy bulk and irregular porous structures were prepared using Selective Laser Melting (SLM). This study systematically investigated the effects of laser power, scanning speed, scanning spacing, and laser energy density on the forming quality of TC4 titanium alloy specimens, through orthogonal experimental design. The research results indicate that laser power is the primary factor affecting the density of TC4 titanium alloy bulk during the SLM process. With the increase of laser energy density, the density of the specimens shows an initial increase followed by a decrease, while Vickers hardness and surface roughness exhibit a decreasing trend followed by an increasing trend. Moreover, the surface of the specimens transforms from a rough surface with a significant presence of pores, voids, or unmelted powder particles to a relatively smooth and flat surface, accompanied by a reduction in the size and quantity of pore defects.

3D-Printed Personalized Lattice Implant as an Innovative Strategy to Reconstruct Geographic Defects in Load-Bearing Bones.

Geographic defect reconstruction in load-bearing bones presents formidable challenges for orthopaedic surgeon. The use of 3D-printed personalized implants presents a compelling opportunity to address this issue. This study aims to design, manufacture, and evaluate 3D-printed personalized implants with irregular lattice porous structures for geographic defect reconstruction in load-bearing bones, focusing on feasibility, osseointegration, and patient outcomes. This retrospective study involved seven patients who received 3D-printed personalized lattice implants for the reconstruction of geographic defects in load-bearing bones. Personalized implants were customized for each patient. Randomized dodecahedron unit cells were incorporated within the implants to create the porous structure. The pore size and porosity were analyzed. Patient outcomes were assessed through a combination of clinical and radiological evaluations. Tomosynthesis-Shimadzu metal artifact reduction technology (T-SMART) was utilized to evaluate osseointegration. Functional outcomes were assessed according to the Musculoskeletal Tumor Society (MSTS) 93 score. Multiple pore sizes were observed in porous structures of the implant, with a wide distribution range (approximately 300-900 um). The porosity analysis results showed that the average porosity of irregular porous structures was around 75.03%. The average follow-up time was 38.4 months, ranging from 25 to 50 months. Postoperative X-rays showed that the implants matched the geographic bone defect well. Osseointegration assessments according to T-SMART images indicated a high degree of bone-to-implant contact, along with favorable bone density around the implants. Patient outcomes assessments revealed significant improvements in functional outcomes, with the average MSTS score of 27.3 (range, 26-29). There was no implant-related complication, such as aseptic loosening or structure failure. 3D-printed personalized lattice implants offer an innovative and promising strategy for geographic defect reconstruction in load-bearing bones. This approach has the potential to match the unique contours and geometry of the geographic bone defect and facilitate osteointegration.

Numerical study of gas–solid transport characteristics within vortex region induced by porous media using lattice-Boltzmann based discrete particle simulation

Porous media, as delivery carriers, holds great potential application in various fields particular in drug delivery. A comprehensive understanding of gas–solid transport characteristics within porous media is significant and regulating retention and release of drug particles. A combined approach of lattice Boltzmann method and time-driven hard-sphere model (LBM-TDHS) was used to investigate particle transport process in porous media. The vortex induced by porous structures was observed. Particle trajectories with different connectivity of the vortex region and inlet flow angles was conducted. This study revealed that fluid velocity between connected regions significantly affects the gas streamlines’ shape and particle trajectories. Different inlet flow angles lead to five modes of particle trajectories in vortex regions. Finally, some modifications were performed in general irregular porous structure to control particle trajectories. LBM-TDHS successfully investigated particle dynamics in vortex regions within porous media, demonstrating potential applicationin optimizing the structure of drug delivery carriers.