Search Results (815)

Background/Objectives: Maxillofacial silicone prostheses’ long-term color stability remains a challenge. This study aimed to evaluate and compare the color stability of conventional and digital maxillofacial silicone elastomers mixed with nano-sized antimicrobial additives (ZnO nanoparticles and chlorhexidine salt-CHX) at various concentrations over a 10-week period. Methods: A total of nine groups (n = 10) of maxillofacial silicone elastomers were prepared. These included a control group (no additives), conventionally pigmented silicone, digitally pigmented silicone (Spectromatch system), and silicone mixed with ZnO or CHX at 1%, 3%, and 5% by weight. Specimens were fabricated in steel molds and cured at 100 °C for 1 h. Color measurements were performed at baseline and after 1, 4, 6, and 10 weeks using a Minolta Chroma Meter (CIELAB system, ΔE₀₀ formula). Data were analyzed using two-way ANOVA and Tukey HSD post hoc tests (α = 0.05). Results: Color changes (ΔE₀₀) ranged from 0.74 to 2.83 across all groups. The conventional pigmented silicone group showed the highest color difference (ΔE₀₀ = 2.83), while the lowest was observed in the ZnO 1% group (ΔE₀₀ = 0.74). Digital silicone and all antimicrobial-modified groups exhibited acceptable color stability (ΔE₀₀ < 3.1). Time significantly affected color difference, with the largest change occurring during the first four weeks (p < 0.05), followed by stabilization. Regression analysis confirmed high color stability over time for all groups except the conventional pigmented group. Conclusions: This is one of the first studies to directly compare digital and conventional pigmentation methods combined with nano-antimicrobials in maxillofacial silicones. Maxillofacial silicone elastomers mixed with up to 5% ZnO or CHX maintained acceptable color stability over 10 weeks. Digital pigmentation is similar to conventional methods. The incorporation of nano-antimicrobials offers significant microbial resistance and improved color retention. Full article

Asphalt plant reclaimed powder is a common solid waste in road engineering. Reusing reclaimed powder as filler holds significant importance for environmental protection and resource conservation. The key factors affecting the feasibility of reclaimed powder reuse are its acidity/alkalinity and cleanliness. Traditional evaluation methods, such as the methylene blue test and plasticity index, can assess reclaimed powder properties to guide its recycling. However, these methods suffer from inefficiency, strong empirical dependence, and high variability. To address these limitations, this study proposes a rapid and precise evaluation method for reclaimed powder properties based on Fourier transform infrared spectroscopy (FTIR). To do so, five field-collected reclaimed powder samples and four artificial samples were evaluated. Scanning electron microscopy (SEM), X-ray fluorescence spectroscopy (XRF), and X-ray diffraction (XRD) were employed to characterize their microphase morphology, chemical composition, and crystal structure, respectively. Subsequently, FTIR was used to establish correlations between key acidity/alkalinity, cleanliness, and multiple characteristic peak intensities. Representative infrared characteristic peaks were selected, and a quantitative functional group index (Is) was proposed to simultaneously evaluate acidity/alkalinity and cleanliness. The results indicate that reclaimed powder primarily consists of tiny, crushed stone particles and dust, with significant variations in crystal structure and chemical composition, including calcium carbonate, silicon oxide, iron oxide, and aluminum oxide. Some samples also contained clay, which critically influenced the reclaimed powder properties. Since both filler acidity/alkalinity and cleanliness are affected by clay (silicon/carbon ratio determining acidity/alkalinity and aluminosilicate content affecting cleanliness), this study calculated four functional group indices based on FTIR absorption peaks, namely the Si-O-Si stretching vibration (1000 cm⁻¹) and the CO₃²⁻ asymmetric stretching vibration (1400 cm⁻¹). These indices were correlated with conventional testing results (XRF for acidity/alkalinity, methylene blue value, and pull-off strength for cleanliness). The results show that the Is index exhibited strong correlations (R² = 0.89 with XRF, R² = 0.80 with methylene blue value, and R² = 0.96 with pull-off strength), demonstrating its effectiveness in predicting both acidity/alkalinity and cleanliness. The developed method enhances reclaimed powder detection efficiency and facilitates high-value recycling in road engineering applications. Full article

A modular strategy for the molecular design of silicone-based antifoaming agents was developed by precisely controlling the architecture of poly (methylhydrosiloxane) (PMHS). Sixteen PMHS variants were synthesized by systematically varying the siloxane chain length (L1–L4), backbone composition (D₃T₁ vs. D₃₀T₁), and terminal group chemistry (H- vs. M-type). These structural modifications resulted in a broad range of Si-H functionalities, which were quantitatively analyzed and correlated with defoaming performance. The PMHS matrices were integrated with high-viscosity PDMS, a nonionic surfactant, and covalently grafted fumed silica—which was chemically matched to each PMHS backbone—to construct formulation-specific defoaming systems with enhanced interfacial compatibility and colloidal stability. Comprehensive physicochemical characterization via FT-IR, ¹H NMR, GPC, TGA, and surface tension analysis revealed a nonmonotonic relationship between Si-H content and defoaming efficiency. Formulations containing 0.1–0.3 wt% Si-H achieved peak performance, with suppression efficiencies up to 96.6% and surface tensions as low as 18.9 mN/m. Deviations from this optimal range impaired performance due to interfacial over-reactivity or reduced mobility. Furthermore, thermal stability and molecular weight distribution were found to be governed by repeat unit architecture and terminal group selection. Compared with conventional EO/PO-modified commercial defoamers, the PMHS-based systems exhibited markedly improved suppression durability and formulation stability in high-viscosity environments. These results establish a predictive structure–property framework for tailoring antifoaming agents and highlight PMHS-based formulations as advanced foam suppressors with improved functionality. This study provides actionable design criteria for high-performance silicone materials with strong potential for application in thermally and mechanically demanding environments such as coating, bioprocessing, and polymer manufacturing. Full article

This study aimed to evaluate the impact of preoperative anti-VEGF injections on pars plana vitrectomy (PPV) outcomes in patients with proliferative diabetic retinopathy (PDR). Material and methods: We analysed 232 eyes with proliferative diabetic vitreoretinopathy treated with posterior vitrectomy. There were 112 women and 120 men. The patients were divided into two groups of 116 eyes each. In 116 eyes (study group), an anti-VEGF injection was administered 3 to 5 days before vitrectomy. The control eyes were not injected with anti-VEGF due to systemic contraindications to anti-VEGF treatment or lack of patient consent. All participants underwent pars plana vitrectomy with silicone oil injection. The oil was removed within 2–3 months after PPV. Results: At 2 years of observation, after removal of silicone oil, visual acuity (VA) was 0.24 ± 0.27 logMAR in the study and 0.37 ± 0.45 logMAR in the control group (p = 0.003). Intraocular pressure was 16.84 ± 6.25 mmHg in the study group and 17.78 ± 6.22 mmHg in the control group (p = 0.04). The mean duration of surgery was 47.62 ± 9.87 and 50.05 ± 9.41 min in the study and control groups, respectively (p = 0.02). The size of intraoperative haemorrhage was 0.97 ± 0.86 dd in the study group and 1.51 ± 1.22 dd in the control group (p = 0.003). The frequency of surgery-induced retinal breaks was 0.34 ± 0.56 in the study group and 0.56 ± 0.76 in the control group (p = 0.003). The recurrence rate of retinal detachment was 0.05 ± 0.22 in the study group and 0.1 ± 0.31 in the control group (p = 0.15). Conclusions: Preoperative anti-VEGF therapy shortens the duration of surgery, reduces complications, and improves long-term outcomes in terms of visual acuity and maintenance of normal eye function. Full article

Against the backdrop of global energy transition and strict environmental regulations, supercritical carbon dioxide (scCO₂) fracturing and oil displacement technologies have emerged as pivotal green approaches in shale gas exploitation, offering the dual advantages of zero water consumption and carbon sequestration. However, the inherent low viscosity of scCO₂ severely restricts its sand-carrying capacity, fracture propagation efficiency, and oil recovery rate, necessitating the urgent development of high-performance thickeners. The current research on scCO₂ thickeners faces a critical trade-off: traditional fluorinated polymers exhibit excellent philicity CO₂, but suffer from high costs and environmental hazards, while non-fluorinated systems often struggle to balance solubility and thickening performance. The development of new thickeners primarily involves two directions. On one hand, efforts focus on modifying non-fluorinated polymers, driven by environmental protection needs—traditional fluorinated thickeners may cause environmental pollution, and improving non-fluorinated polymers can maintain good thickening performance while reducing environmental impacts. On the other hand, there is a commitment to developing non-noble metal-catalyzed siloxane modification and synthesis processes, aiming to enhance the technical and economic feasibility of scCO₂ thickeners. Compared with noble metal catalysts like platinum, non-noble metal catalysts can reduce production costs, making the synthesis process more economically viable for large-scale industrial applications. These studies are crucial for promoting the practical application of scCO₂ technology in unconventional oil and gas development, including improving fracturing efficiency and oil displacement efficiency, and providing new technical support for the sustainable development of the energy industry. This study innovatively designed an amphiphilic modified amino silicone oil polymer (MA-co-MPEGA-AS) by combining maleic anhydride (MA), methoxy polyethylene glycol acrylate (MPEGA), and amino silicone oil (AS) through a molecular bridge strategy. The synthesis process involved three key steps: radical polymerization of MA and MPEGA, amidation with AS, and in situ network formation. Fourier transform infrared spectroscopy (FT-IR) confirmed the successful introduction of ether-based CO₂-philic groups. Rheological tests conducted under scCO₂ conditions demonstrated a 114-fold increase in viscosity for MA-co-MPEGA-AS. Mechanistic studies revealed that the ether oxygen atoms (Lewis base) in MPEGA formed dipole–quadrupole interactions with CO₂ (Lewis acid), enhancing solubility by 47%. Simultaneously, the self-assembly of siloxane chains into a three-dimensional network suppressed interlayer sliding in scCO₂ and maintained over 90% viscosity retention at 80 °C. This fluorine-free design eliminates the need for platinum-based catalysts and reduces production costs compared to fluorinated polymers. The hierarchical interactions (coordination bonds and hydrogen bonds) within the system provide a novel synthetic paradigm for scCO₂ thickeners. This research lays the foundation for green CO₂-based energy extraction technologies. Full article

Room-temperature vulcanizing (RTV) silicone foams are used in many industrial applications that require the material to perform over long time periods. However, mechanical properties tend to deteriorate when these foams age under a compressive load. The chemical aging is attributed to the presence of unreacted functional groups of the prepolymers, residues from acid, and catalytically active tin (II) species. Here, an optimized thermal treatment of an RTV foam that achieves completion of curing reactions and deactivation of reactive species is proposed. Foams that were thermally aged for three months under compressive load showed no signs of compression set, indicative of the effectiveness of the implemented post-curing approach. In addition, the effects of fillers (diatomaceous earth, fumed silica, and carbon nanofibers) on thermomechanical properties were investigated. Tensile strength, tear strength, and thermal conductivity increased when these fillers were added to the unfilled RTV formulation, with carbon nanofibers (CNFs) being the most effective filler. Rheological studies of RTV formulations indicated that 2.5 wt.% of CNFs is the upper limit that can be added to the RTV formulation. Full article

Precise photovoltaic (PV) performance modeling is essential for optimizing system design, operational monitoring, and reliable power forecasting—yet spectral correction is often overlooked, despite its significant impact on energy yield uncertainty. This study employs the FARMS-NIT model to assess the impact of spectral irradiance on eight PV technologies across 79 European sites, grouped by Köppen–Geiger climate classification. Unlike previous studies limited to clear-sky or single-site analysis, this work integrates satellite-derived spectral data for both all-sky and clear-sky scenarios, enabling hourly, tilt-optimized simulations that reflect real-world operating conditions. Spectral analyses reveal European climates exhibit blue-shifted spectra versus AM1.5 reference, only 2–5% resembling standard conditions. Thin-film technologies demonstrate superior spectral gains under all-sky conditions, though the underlying drivers vary significantly across climatic regions—a distinction that becomes particularly evident in the clear-sky analysis. Crystalline silicon exhibits minimal spectral sensitivity (<1.6% variations), with PERC/PERT providing highest stability. CZTSSe shows latitude-dependent performance with ≤0.7% variation: small gains at high latitudes and losses at low latitudes. Atmospheric parameters were analyzed in detail, revealing that air mass (AM), clearness index (K_t), precipitable water (W), and aerosol optical depth (AOD) play key roles in shaping spectral effects, with different parameters dominating in distinct climate groups. Full article

The interest in macromolecular alkoxysilyl-functionalized hybrids (self-assembling or nanostructured), which could be used as precursors in biomimetic silica precipitation and for the synthesis of hollow spherical silica particles, is growing. Nevertheless, reports on all-organosilicon systems for bioinspired silica precipitation are scarce. Therefore, a new kind of polyalkoxysilane macromonomer–linear polysilsesquioxane (LPSQ) of ladder-like backbone, functionalized in side chains with trimethoxysilyl groups (LPSQ-R-Si(OMe)₃), was designed following this approach. It was obtained by photoinitiated thiol-ene addition of 3-mercaptopropyltrimethoxysilane to the vinyl-functionalized polysilsesquioxane precursor, carried out in situ in tetraethoxysilane (TEOS). The mixture of LPSQ-R-Si(OMe)₃ and TEOS (co-monomers) was used in a sol–gel process conducted under acidic conditions (0.5 M HCl/NaCl) in the presence of Pluronic^® F-127 triblock copolymer as a template. LPSQ-R-Si(OMe)₃ played a key role for the formation of microparticles of a spherical shape that were formed under the applied conditions, while their size (as low as 3–4 µm) was controlled by the stirring rate. The hybrid materials were hydrophobic and showed good thermal and oxidative stability. Introduction of zinc acetate (Zn(OAc)₂) as an additive in the sol–gel process influenced the pH of the reaction medium, which resulted in structural reinforcement of the hybrid microparticles owing to more effective condensation of silanol groups and a relative increase of the content of SiO₂. The proposed method shows directions in designing the properties of hybrid materials and can be translated to other silicon–organic polymers and oligomers that could be used to produce hollow silica particles. The established role of various factors (macromonomer structure, pH, and stirring rate) allows for the modulation of particle morphology. Full article

Bovine papillomatosis, caused by a growing group of bovine papillomaviruses (BPVs), is a disease with benign proliferative lesions (papillomas) that may progress to malignancies due to immunological, environmental, or viral factors. This study investigated BPV type diversity in cattle from the Province Santo Domingo de Tsáchilas in Ecuador. Warty lesions were collected from 30 cattle across eight farms. Nucleic acids were extracted using a silicon dioxide-based method, and the partial L1 gene was amplified with PCR. DNA sequences were analyzed using maximum likelihood phylogenetics. Fifty-seven warty lesions yielded ten well-known BPV types: BPV1, BPV2, BPV4, BPV6, BPV8, BPV9, BPV10, BPV13, BPV14, and BPV42. Recently described viral types, BPV-CR2 from Costa Rica and BPV/BR-UEL08 from Brazil, were also detected, alongside a putative novel viral type, BPVEC2024-6-22.1—likely belonging to the genus Xipapillomavirus. This genus had the highest overall count. In contrast, Deltapapillomaviruses were found across all sampled farms. This study underscores BPV diversity in this localized region of Ecuador, and includes genotypes linked to cancers such as enzootic hematuria. The findings provide important epidemiological insights, contributing to vaccine development or immune therapy and improved disease management. Full article

The modern world has brought extensive socioeconomic and ecological changes. Urbanization in developing nations has significantly increased municipal solid waste, necessitating in-depth understanding of waste composition particularly in developing nations for sustainable management practices. This study aimed to classify and characterize waste while evaluating potential waste management methods. Mixed methods were used to examine landfilled waste from Soshanguve and Hatherley sites in Tshwane Metropolitan, South Africa, using techniques such as Fourier transform infrared spectroscopy, X-ray fluorescence, proximate, and ultimate analysis. Seasonal variations in waste components were analysed over two seasons. The study identified that both sites are predominantly composed of organic waste, accounting for over 42 wt.%, with moisture content of ~50 wt.%, and minimal recyclables (<5 wt.%). Seasonal variations in MSW were significant for glass (<4% increase), organic waste (<5% increase), while plastic decreased by ~7% during spring. The biodegradable waste showed high carbon (>50%) and oxygen (>40%) levels, low ash content (<18%), and calorific values of 15–19 MJ/kg. Biodegradables mainly contained oxides of calcium, silicon, iron (III), and potassium with chemical composition indicating functional groups that emphasize composting and energy recovery benefits. The research provides insights into sustainable waste management, revealing waste composition at Tshwane landfills, aiding informed decision-making for resource usage and environmental conservation. Full article

There is considerable interest in broadband nanomaterials, particularly transparent semiconductor oxides, within both fundamental research and technological applications. Historically, it has been considered that the variation in dopant concentration during the synthesis of semiconductor materials is a crucial factor in activating and/or modulating the optical and structural properties, particularly the bandgap and the parameters of the unit cell, of semiconductor oxides. Recently, tin oxide has emerged as a key material due to its excellent structural properties, optical transparency, and various promising applications in optoelectronics. This study utilized the ultrasonic spray pyrolysis technique to synthesize aluminum-doped tin oxide (ATO) thin films on quartz and polished single-crystal silicon substrates. The impact of varying aluminum doping levels (0, 2, 5, and 10 at. %) on morphology and structural and optical properties was examined. The ATO thin films were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmittance spectroscopy. SEM images demonstrated a slight reduction in the size of ATO nanoparticles as the aluminum doping concentration increased. XRD analysis revealed a tetragonal crystalline structure with the space group P42/mnm, and a shift in the XRD peaks to higher angles was noted with increasing aluminum content, indicating a decrease in the crystalline lattice parameters of ATO. The transmittance of the ATO films varied between 75% and 85%. By employing the transmittance spectra and the established Tauc formula the optical bandgap values of ATO films were calculated, showing an increase in the bandgap with higher doping levels. These findings were thoroughly analyzed and discussed; additionally, an effort was made to clarify the contradictory analyses present in the literature and to identify a doping range that avoids the onset of a secondary phase. Full article

Objectives: Persistent Human Papillomavirus (HPV) infection in the cervix and the preinvasive lesions it causes are significant risk factors for cervical cancer. Therefore, a treatment strategy is necessary to facilitate the clearance of HPV and prevent the progression of preinvasive lesions without causing cervical tissue destruction. This study aimed to evaluate the effectiveness of a vaginal adsorbent gel composed of a hydroxyethyl cellulose matrix formulation containing dispersed silicon dioxide, antioxidant sodium selenite, deflamin, and citric acid in patients with HPV infection. Methods: The study was designed as a retrospective cohort study and involved 449 women infected with HPV. For the purposes of the study, the patients were divided into two groups: the treatment group (TG) comprised 207 patients who used the vaginal gel daily for a period of three months, while the control group (CG), consisting of 242 patients, received no treatment under an “active surveillance” protocol. The study’s endpoints encompassed the domains of cytology, histology, and HPV clearance. Results: The regression rate of smear pathologies was 24.8% in the control group and 29.0% in the group using the vaginal adsorbent gel. In the first year, the histological regression rate in cervical biopsies was 49.3% in the treatment group and 19.4% in the control group, with a significant difference between groups (p < 0.001). Moreover, the clearance rate of HPV types was found to be significantly higher in the group using the vaginal adsorbent gel. Conclusions: The findings of this study suggest that the outpatient treatment approach can effectively prevent the oncogenic progression of cervical dysplasia. This alternative method has been shown to be efficacious in preventing the progression of cervical dysplasia and promoting regression. Furthermore, the efficacy of this gel in eradicating HPV has been demonstrated within a 12-month period. Full article

Background/Objectives: Artificial tendons offer an alternative to biological tendon grafts and may restore normative biomechanical functions in humans and animals suffering segmental or complete tendon loss. The aim of this study was to quantify movement biomechanics during hopping gait and muscle properties of New Zealand White rabbits with a polyester silicone-coated (PET-SI) artificial tendon. Methods: In five rabbits, the biological Achilles tendon of the left hindlimb was surgically replaced with a PET-SI artificial tendon; five operated control rabbits underwent complete surgical excision of the biological Achilles tendon in the left hindlimb with no replacement (TE). Results: Across both groups at 2 and 8 weeks post-surgery compared to baseline, the maximum ankle angle during stance and swing phases of stride was significantly lower (i.e., more dorsiflexed) (p < 0.001), the peak vertical force was significantly higher (p < 0.001), and the average ground contact area was significantly lower (p < 0.001). At 8 weeks post-surgery, the muscle cross-sectional area of the lateral gastrocnemius was significantly higher in the PET-SI group than in the TE group (p = 0.006). Muscle mass and length were lower in the operated limb compared to the non-operated limb across the two groups (TE and PET-SI), with no significant differences between groups. Conclusions: The artificial Achilles tendon did not appear to provide superior biomechanical support during hopping compared to the TE group. However, the artificial tendon preserved muscle structural properties that correspond to the muscle’s capacity to generate force. Future studies should optimize the tendon–tissue interface. Full article

The success of adhesive restorations largely depends on the optimal bond strength between the tooth structure and the restorative material. The aim of this study was to evaluate the shear bond strength (SBS) of four different adhesives applied to mandibular molars on deep and superficial dentin. The total of 56 teeth used in the study were randomly divided into 2 subgroups of superficial dentin and deep dentin participants (n = 28). Superficial and deep dentin groups were randomly divided into 4 subgroups (n = 7) for application with different adhesive agents. We formed the following groups: Group 1 (G1)—deep dentin and GC bonding agent (G-Premio BOND); Group 2 (G2)—superficial dentin and GC bonding agent; Group 3 (G3)—deep dentin and Clearfil S3 bond bonding agent (Clearfil TM S3 BOND); Group 4 (G4)—superficial dentin and Clearfil S3 bond bonding agent; Group 5 (G5)—deep dentin and KerrOptibond bonding agent (KerrOptibond^TM Universal); Group 6 (G6)—superficial dentin and Kerr Optibond bonding agent; Group 7 (G7)—deep dentin and 3M-ESPE universal bonding agent (3M ESPE); Group 8 (G8)—superficial dentin and 3M-ESPE universal bonding agent. The silicone block with a diameter of 3 mm and a thickness of 1 mm was placed in the middle of the occlusal surface and the test composite was loaded. All prepared specimens were aged in thermal cycles at 5–55 °C for 5000 cycles. The teeth were subjected to SBS (shear bond strength) tests at a crosshead speed of 1 mm/min in a universal testing machine. In all adhesive systems, deep dentin showed a higher bond strength than superficial dentin and the bond strength value was statistically significant (p = 0.05). The bond strength in all tested adhesive systems was observed to be significantly higher in deep dentin than in superficial dentin. Full article

Microfluidic devices are used in numerous scientific fields and research areas, but device fabrication is still a time- and resource-intensive process largely confined to the cleanroom or a similarly well-equipped laboratory. This paper presents a method to create microfluidic devices in under three hours using the silicone polymer polydimethylsiloxane (PDMS) and a laser cut positive master using PDMS double casting without a cleanroom or other large capital equipment. This method can be utilized by an undergraduate student with minimal training in a laboratory with a modest budget. This paper presents “Same Day Microfluidics” as a fabrication method accessible to research groups not currently fabricating their own microfluidic devices and as an option for established research groups to more quickly create prototype devices. The method is described in detail with timing, materials, and technical considerations for each step and demonstrated in the context of a Y-channel coflow device. Full article