Search Results (22)

Recurrent urinary tract infection (rUTI) continues to pose a formidable clinical challenge, largely owing to the rapid clearance of therapeutic agents from the bladder caused by short intravesical residence time and periodic urinary voiding. Although intravesical drug delivery has emerged as a promising local therapeutic strategy, conventional liquid instillations and physically crosslinked hydrogels frequently fail to sustain structural integrity and prolonged drug release within the dynamically changing bladder microenvironment. Herein, we develop a photocrosslinkable, pH-responsive intravesical floating drug delivery system (iFDDS) for sustained antimicrobial delivery. This system is fabricated using diacrylated Pluronic F127 (F127DA) as the core network-building component. The covalently crosslinked F127DA network confers superior mechanical stability while preserving amphiphilic micellar domains that enable efficient loading of hydrophobic drugs. A tertiary amine-based pH-responsive crosslinker (CLMA) is further integrated into the hydrogel matrix, endowing iFDDS with enhanced swelling capacity under the mildly acidic microenvironment. Additionally, lyophilization-induced porous architecture reduces the apparent density of the iFDDS below that of urine, achieving stable flotation for over 48 h and effectively mitigating the risk of urinary tract obstruction. The optimized iFDDS exhibits favorable catheter deliverability, shear-thinning rheological behavior adaptable to dynamic fluid conditions, and excellent biocompatibility with bladder epithelial cells. Upon loading with rifampicin, the iFDDS demonstrates potent and sustained antibacterial efficacy against Escherichia coli. This study establishes a robust, environment-adaptive platform for intravesical therapy, offering a viable strategy to address the short residence time limitation of conventional formulations and improve the therapeutic management of rUTI. Full article

To address the integrated demands of structural reinforcement and energy-efficient retrofitting for existing buildings, a cementitious material modified with vitrified microspheres and SiO₂ aerogel was developed to realize the synergistic enhancement of thermal insulation and mechanical strength. By substituting fine sand with equal mass fractions of SiO₂ aerogel and vitrified microspheres in the cement matrix, this study systematically investigated the synergistic regulatory effects of this binary modification on two core performance metrics—thermal conductivity and compressive strength. All performance tests were conducted in triplicate, and the results are presented as the mean values. The results indicated that the thermal conductivity of the composite exhibited a trend of decreasing first and then increasing with the rise in aerogel content. At an aerogel dosage of 6%, the thermal conductivity dropped to 0.2237 W/(m·K), achieving optimal thermal insulation performance while retaining a compressive strength of 17.96 MPa. The subsequent incorporation of 15% vitrified microspheres further reduced the thermal conductivity to 0.1642 W/(m·K) while maintaining a compressive strength of 15.34 MPa, thereby achieving an optimal balance between thermal insulation and mechanical performance. Microstructural characterization revealed that the incorporation of aerogel significantly increased the internal porosity of the composite, effectively reducing thermal conductivity by obstructing heat transfer pathways. Vitrified microspheres enhance thermal resistance via their closed-cell structure and promote the formation and densification of C-S-H gel. Synergistically with SiO₂ aerogel, they construct a multi-scale porous composite system. By optimizing the interfacial bonding state and pore structure, this system achieves the synergistic optimization of mechanical strength and thermal insulation of cement-based composites, providing new materials and a theoretical basis for the functional integrated retrofitting of existing building structures. Full article

Endoscopic biliary drainage using self-expanding metal stents (SEMSs) is a standard palliative therapy for cholangitis and obstructive jaundice caused by malignant distal biliary obstruction (MDBO). Fully-covered SEMSs (FC-SEMSs) prevent tumor ingrowth and provide longer patency; however, recent advances in chemotherapy have increased stent migration due to tumor shrinkage, resulting in reduced functional patency compared with uncovered SEMSs. Partially covered SEMSs can reduce migration but are often difficult to remove after deployment. In addition, adverse events such as acute pancreatitis and cholecystitis remain a concern with FC-SEMSs. To address these limitations, Dr. Kobayashi introduced a novel porous SEMS with multiple side holes in the covering membrane (MH-SEMSs) in 2019. This design allows limited bile duct epithelial ingrowth through side holes, providing anchorage while maintaining removability. The side-hole structure may also reduce cholecystitis and pancreatitis by preserving flow through the pancreatic and cystic duct orifices. Over five years since their introduction, clinical evidence supporting MH-SEMSs has steadily increased. This review summarizes current data and explores future perspectives for MH-SEMS use in MDBO management. Full article

Flexible strain sensors capable of conformal integration with living organisms are essential for advanced wearable electronics, human–machine interaction, and plant health. However, many existing sensors require complex fabrication or rely on non-breathable elastomer substrates that interfere with the physiological microenvironment of skin or plant tissues. Here, we present a low-cost, breathable, and highly stretchable strain sensor constructed from biomedical materials, in which a double-layer medical elastic bandage serves as the porous substrate and an intermediate conductive medical elastic tape impregnated with carbon nanotubes (CNTs) ink acts as the sensing layer. Owing to the hierarchical textile porosity and the deformable CNTs percolation network, the sensor achieves a wide strain range of 100%, a gauge factor of up to 2.72, and excellent nonlinear second-order fitting (R² = 0.997). The bandage substrate provides superior air permeability, allowing long-term attachment without obstructing moisture and gas exchange, which is particularly important for maintaining skin comfort and preventing disturbances to plant epidermal physiology. Demonstrations in human joint-motion monitoring and real-time plant growth detection highlight the device’s versatility and biological compatibility. This work offers a simple, low-cost yet effective alternative to sophisticated strain sensors designed for human monitoring and plant growth monitoring, providing a scalable route toward multifunctional wearable sensing platforms. Full article

Although numerous studies have investigated individual methods to improve the performance of solar air heaters (SAHs), such as flow obstruction barriers, porous media, nanofluids, and thermal energy storage units, the overall integration of these reinforcement strategies into a unified, sustainable system remains to be defined. The current study presents a hybrid solar air heating configuration that combines a solar air collector (SAC) with an electric air heater (EAH) powered by photovoltaic (PV) panels, aiming to stabilize outlet air temperature and enhance overall thermal efficiency. Experimental and numerical approaches were employed to evaluate the influence of barrier geometry (flat, trapezoidal, and V-groove) and airflow rate (53, 158, and 317 L/min) on system performance using three SAC models. Experimental results revealed that lower airflow rate promotes greater temperature rise (ΔT) due to longer air–surface contact, while V-groove barriers achieved the highest ΔT and collector efficiency among all configurations. At higher airflow rates, the absorbed energy factor Fc (τα) increased to approximately 0.73, whereas the heat loss factor FcU decreased, indicating reduced thermal losses and improved energy transfer. Model III demonstrated the most effective heat absorption, confirming its superior thermal design. The integrated SAC–EAH system exhibited improved overall efficiency, with the SAC functioning effectively as a preheating unit and the EAH sustaining thermal stability during variable solar conditions. Numerical results showed that the highest temperature difference occurs at the V-groove barriers at an air flow rate of 53 L/min. In contrast, the difference between inlet and outlet temperatures decreases across the remaining models, with reduced percentages of 11.8% and 12.7% for Model II and Model I, respectively. Numerical simulations ensured the experimental outcomes, showing close agreement with the temperature variation trends and validating the system’s enhanced thermal performance. Full article

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality worldwide. Although conventional therapies are effective in controlling symptoms, they remain limited in altering the course of the disease and significantly reducing the chronic inflammation and oxidative stress underlying it. In this context, nanoparticles and nanomaterials are emerging as innovative tools capable of overcoming traditional pharmacological barriers due to their ability to deliver therapeutic oligonucleotides, antioxidants, and drugs in a targeted manner, modulate immune responses, and improve the bioavailability of active compounds. In particular, metal–organic frameworks (MOFs) stand out as ideal candidates for inhalable drug delivery in COPD, owing to their permanent crystalline porous structure, high specific surface area, and versatile chemical functionalization. This review provides the most recent preclinical evidence on the use of different nanoparticles in COPD, with a focus on the therapeutic and diagnostic potential of MOFs. It discusses their biocompatibility, drug loading strategies, and controlled release mechanisms and explores future perspectives for clinical translation. Full article

Stones are traditionally used in construction and architectural applications as building elements due to their aesthetic and technical/structural performance. Like other environmental factors (rain, humidity, moisture, salt presence, biological activity, etc.), heating–cooling and freeze–thaw cycles significantly threaten the longevity of stone materials. Hence, considering the socio-economic and cultural value of stones, preventive actions such as hydrophobic coatings are applied to prevent or mitigate damage. The scope of this study is the performance assessment of limestones with different characteristics and the efficiency of various commercial silane/siloxane-based hydrophobic coatings when exposed to thermal variation and freeze–thaw. For that purpose, the standards EN 14066:2013 (determination of resistance to aging by thermal shock) and EN 12371:2010 (determination of frost resistance) were followed. Open porosity and static contact angles were estimated to assess the stone durability and water protection capabilities of the hydrophobics. Additionally, sound speed propagation velocity, quality of building material index, elastic modulus and flexural strength were measured to evaluate the variation of mechanical properties. Static contact angle revealed that the coatings maintained an efficient level of hydrophobicity even after thermal-shock and freeze–thaw weathering tests. The study also revealed a critical interaction between freeze–thaw cycles, hydrophobic coatings and structural integrity of the stones, mostly on more porous ones. When they are subjected to harsh environmental conditions, untreated porous limestones keep structural cohesion, allowing for the natural absorption and release of water during freezing and thawing. On the contrary, when limestones are treated, the hydrophobic coatings can moderately obstruct the water release due to the partial saturation of the porous framework by the products. It also probably resulted from the different mechanical behavior between the inner matrix and layer of stone coated, resulting in a premature breakout and mechanical damage of the stone. Full article

Using underground hydrogen storage technology has been recognized as an effective way to store hydrogen on a large scale, yet the physical mechanisms of hydrogen flow in porous media remain complex and challenging. Studying the heterogeneity of pore structures is crucial to enhance the efficiency of hydrogen storage. In order to better understand the pore-scale behavior of hydrogen in underground heterogeneous porous structures, this paper investigates the effects of wettability, pore–throat ratio, and pore structure heterogeneity on the behavior of the two-phase H₂–brine flow using pore-scale simulations. The results show that the complex interactions between wettability, heterogeneity, and pore geometry play a crucial role in controlling the repulsion pattern. The flow of H₂ is more obstructed in the region of the low pore–throat ratio, and the obstructive effect is more obvious when adjacent to the region of the high pore–throat ratio than that when adjacent to the region of the medium pore–throat ratio. In high-pore–throat ratio structures, the interfacial velocity changes abruptly as it passes through a wide pore and adjacent narrower throat. Interfacial velocities at the local pore scale may increase by several orders of magnitude, leading to non-negligible viscous flow effects. It is observed that an increase in the pore–throat ratio from 6.35 (low pore–throat ratio) to 12.12 (medium pore–throat ratio) promotes H₂ flow, while an increase from 12.12 (medium pore–throat ratio) to 23.67 (high pore–throat ratio) negatively affects H₂ flow. Insights are provided for understanding the role of the heterogeneity of pore structures in H₂–brine two-phase flow during underground hydrogen storage. Full article

In this work, non-ordered and ordered CeO₂-based catalysts are proposed for CO₂ conversion to dimethyl carbonate (DMC). Particularly, non-ordered mesoporous CeO₂, consisting of small nanoparticles of about 8 nm, is compared with two highly porous (635–722 m²/g) ordered CeO₂@SBA-15 nanocomposites obtained by two different impregnation strategies (a two-solvent impregnation method (TS) and a self-combustion (SC) method), with a final CeO₂ loading of 10 wt%. Rietveld analyses on XRD data combined with TEM imaging evidence the influence of the impregnation strategy on the dispersion of the active phase as follows: nanoparticles of 8 nm for the TS composite vs. 3 nm for the SC composite. The catalytic results show comparable activities for the mesoporous ceria and the CeO₂@SBA-15_SC nanocomposite, while a lower DMC yield is found for the CeO₂@SBA-15_TS nanocomposite. This finding can presumably be ascribed to a partial obstruction of the pores by the CeO₂ nanoparticles in the case of the TS composite, leading to a reduced accessibility of the active phase. On the other hand, in the case of the SC composite, where the CeO₂ particle size is much lower than the pore size, there is an improved accessibility of the active phase to the molecules of the reactants. Full article

Microbial fuel cell (MFC) performance is affected by the metabolic activity of bacteria and the extracellular electron transfer (EET) process. The deficiency of nanostructures on macroporous anode obstructs the enrichment of exoelectrogens and the EET. Herein, a N-doped carbon nanowire-modified macroporous carbon foam was prepared and served as an anode in MFCs. The anode has a hierarchical porous structure, which can solve the problem of biofilm blockage, ensure mass transport, favor exoelectrogen enrichment, and enhance the metabolic activity of bacteria. The microscopic morphology, spectroscopy, and electrochemical characterization of the anode confirm that carbon nanowires can penetrate biofilm, decrease charge resistance, and enhance long-distance electron transfer efficiency. In addition, pyrrolic N can effectively reduce the binding energy and electron transfer distance of bacterial outer membrane hemin. With this hierarchical anode, a maximum power density of 5.32 W/m³ was obtained, about 2.5-fold that of bare carbon cloth. The one-dimensional nanomaterial-modified macroporous anodes in this study are a promising strategy to improve the exoelectrogen enrichment and EET for MFCs. Full article

In this paper, the effect of TiC particle size on the microstructure and mechanical properties of an Inconel 718/TiC composite material fabricated using binder jetting additive manufacturing was investigated. Vacuum sintering, hot isostatic pressing and heat treatment as post-processing were applied to the samples. The addition of 1 wt% micron-sized TiC to the Inconel 718 matrix resulted in a significant increase in strength and relative elongation during tensile tests at both room temperature and 700 °C. The distribution of micron-sized TiC particles in the matrix was uniform, and the MC phase precipitated after HT was located along the grain boundaries and near the micron-sized TiC particles, which contributed to the strengthening. The hardness increased insignificantly with the addition of micron-sized TiC. The nano-sized TiC particles added to the matrix were located on the surfaces of the Inconel 718 particles of the initial powders, which obstructed sintering and resulted in a porous structure and, consequently, low mechanical properties. Full article

Porous polymer gels (PPGs) are characterized by inherent porosity, a predictable structure, and tunable functionality, which makes them promising for the heavy metal ion trap in environmental remediation. However, their real-world application is obstructed by the balance between performance and economy in material preparation. Development of an efficient and cost-effective approach to produce PPGs with task-specific functionality remains a significant challenge. Here, a two-step strategy to fabricate amine-enriched PPGs, NUT-21-TETA (NUT means Nanjing Tech University, TETA indicates triethylenetetramine), is reported for the first time. The NUT-21-TETA was synthesized through a simple nucleophilic substitution using two readily available and low-cost monomers, mesitylene and α, α′-dichloro-p-xylene, followed by the successful post-synthetic amine functionalization. The obtained NUT-21-TETA demonstrates an extremely high Pb²⁺ capacity from aqueous solution. The maximum Pb²⁺ capacity, q_m, assessed by the Langmuir model was as high as 1211 mg/g, which is much higher than most benchmark adsorbents including ZIF-8 (1120 mg/g), FGO (842 mg/g), 732-CR resin (397 mg/g), Zeolite 13X (541 mg/g), and AC (58 mg/g). The NUT-21-TETA can be regenerated easily and recycled five times without a noticeable decrease of adsorption capacity. The excellent Pb²⁺ uptake and perfect reusability, in combination with a low synthesis cost, gives the NUT-21-TETA a strong potential for heavy metal ion removal. Full article

Based on fuel crossover behavior and bubble nucleation in the microfluidic fuel cell’s channel, this research numerically presents the performance of air-breathing direct formic acid microfluidic fuel cells. In the simulation, a three-dimensional microfluidic fuel cell model was used. The continuity, momentum, species transport, and charge equations were used to develop the model transport behavior, whereas the Brinkman equation represented the porous medium flow in the gas diffusion layer. The I–V and power density curves are generated using the Butler–Volmer equation. The simulation and current experimental data were compared under identical operating conditions to validate the I–V curve of the microfluidic fuel cell model. The model was used to investigate the current density distribution in the microchannel due to bubble obstruction and the reactant concentration on both electrodes. Fuel crossover resulted in a large decrease in open-circuit voltage and a reduction in fuel concentration above the anode electrode. The findings also showed that a low-flow rate air-breathing direct formic acid microfluidic fuel cell is more prone to CO₂ bubble formation. Full article

Calcium phosphate (CaP) biomaterials are extensively used to reconstruct bone defects. They resemble a chemical similarity to the inorganic mineral present in bones. Thus, they are termed as the key players in bone regeneration. Sintering is a heat treatment process applied to CaP powder compact or fabricated porous material to impart strength and integrity. Conventional sintering is the simplest sintering technique, but the processing of CaPs at a high temperature for a long time usually leads to the formation of secondary phases due to their thermal instability. Furthermore, it results in excessive grain growth that obstructs the densification process, limiting the application of CaP’s ceramics in bone regeneration. This review focuses on advanced sintering techniques used for the densification of CaPs. These techniques utilize the synergy of temperature with one or more parameters such as external pressure, electromagnetic radiation, electric current, or the incorporation of transient liquid that boosts the mass transfer while lowering the sintering temperature and time. Full article

Reticulate porous ceramic reactors use foam-type absorbers in their operation which must fulfill two essential functions: favoring the volumetric effect and increasing the mass and heat transfer by acting as a support for the reactive materials. Heating these absorbers with highly inhomogeneous concentrate irradiation induces high thermal gradients that affect their thermal performance. Owing to the critical function of these component in the reactor, it is necessary to define a selection criterion for the foam-type absorbers. In this work, we performed an experimental and numerical thermal analysis of three partially stabilized zirconia (PSZ) foam-type absorbers with pore density of 10, 20, and 30 PPI (pores per inch) used as a volumetric absorber. A numerical model and an analytical approximation were developed to reproduce experimental results, and calculate the thermal conductivity, as well as volumetric heat transfer coefficient. The results show that an increase in pore density leads to an increase in the temperature difference between the irradiated face and the rear face of the absorber, this occurs because when pore density increases the concentrated energy no longer penetrates in the deepest space of the absorber and energy is absorbed in areas close to the surface; therefore, temperature gradients are created within the porous medium. The opposite effect occurs when the airflow rate increases; the temperature gradient between the irradiated face and the rear face is reduced. This behavior is more noticeable at low pore densities, but at high pore densities, the effect is less relevant because the internal structure of porous absorbers with high pore density is more complex, which offers obstructions or physical barriers to airflow and thermal barriers to heat transfer. When the steady state is reached, the temperature difference between the two faces of the absorber remains constant if the concentrate irradiation changes slightly, even changing the airflow rate. The results obtained in this work allow us to establish a selection criterion for porous absorbers that operate within solar reactors; this criterion is based on knowledge of the physical properties of the porous absorber, the environment, the working conditions, and the results expected. Full article