Applied Nanotech (United States)

Composite nanofibers of polyvinyl alcohol/carboxymethyl cellulose/collagen (PVA/CMC/Col) were successfully fabricated using the electrospinning method, incorporating various proportions of each component. These nanofibers were meticulously characterized using advanced analytical techniques, including Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and mechanical testing, to ensure a comprehensive understanding of their structural and functional properties. The resulting nanofibers displayed a uniaxial structure with mean diameters ranging from 224 to 408 nm, showcasing precise control over the electrospinning process. The results revealed a direct correlation between material composition and performance, with the PCC5 formulation emerging as the optimal sample. This was evidenced by FTIR and TGA data, which confirmed that an increased collagen concentration led to a more integrated polymer network with enhanced intermolecular hydrogen bonding and superior thermal stability. Furthermore, mechanical testing demonstrated that the PCC5 sample exhibited the highest tensile strength, solidifying the link between chemical composition and robust physical properties. The biocompatibility of the nanofibers was rigorously evaluated through in vitro testing on MG-63 osteoblast-like cells using the MTT assay. The results revealed excellent compatibility with the cellular environment, with the PCC5 sample consistently promoting the highest rates of cell adhesion and proliferation. This study underscores the groundbreaking potential of PVA/CMC/Col nanofibers in the field of bone tissue engineering, as their optimized blend of physical and biological properties makes them a promising candidate for bone regeneration applications. This research paves the way for future advancements in regenerative medicine, offering a robust platform for further exploration and innovation.

Quantum dots attract significant attention as one of the most promising colloidal nanocrystals with unique optical properties and potential applications for the next generation of display technology. In this paper, we evaluate the performance of CdZnSeS-based alloyed-shell quantum dots (QDs) for electroluminescence devices upon additional shell growth and ligand exchange. This includes core/shell (C/S) and core/shell/shell (C/S/S) QDs, whose latter includes an additional ZnS shell and octanethiol (OT) ligands. We present detailed characterizations of QDs using transmission electron microscopy, XRD, and various spectroscopic techniques and demonstrate their QD light emitting (QLEDs). We find the photoluminescence quantum yield of C/S/S QDs increased from 68.8% to 88.7% compared to C/S QDs whereas the emission linewidth narrows from 22.2 nm to 20.8 nm. QLEDs fabricated with C/S/S QDs exhibit a higher peak external quantum efficiency (EQE) of 4.1% and maximum luminance of 85 000 cd m-2, compared to 2.3% EQE and 67 000 cd m-2for C/S QLEDs. In this respect, the OT-assisted shell growth significantly improves the optical property of QDs and performance of QLEDs, likely attributed to the enhanced charge balance and increased radiative recombination rate.

This work presents an experimentally viable synthetic approach for developing visible light-active water-splitting photocatalysts based on organic semiconductors with tunable bandgaps. Chromophore–catalyst dyad assemblies were synthesized by covalently linking catalytic units to donor–acceptor conjugated organic semiconductors. These ensembles demonstrate photocatalytic activity, with hydrogen evolution rates of 1.12 mmol g–1 h–1 and oxygen evolution rates of 420 μmol g–1 h–1 during 12-h studies. Computational analyses indicate that the improved performance results from advantageous energy level alignment between the chromophore and catalytic unit, promoting efficient charge transfer. This research illustrates the feasibility of organic semiconductor photocatalysts for sustainable hydrogen generation and offers mechanistic insights to inform future advancements in clean energy technology.

In 2024, the AmericanChemical Society (ACS), Division of PolymericMaterials: Science and Engineering (PMSE), celebrated its centennial.This historic occasion was marked at the 2024 Spring ACS Meeting inNew Orleans with a Centennial Symposium entitled “PMSECentennial: Celebration of Success and New Frontiers in PolymericMaterials Science and Engineering”. The symposiumreflected on past scientific breakthroughs, technological advancements,and new frontiers in the field of polymeric materials science andengineering. Eight thematic areas comprised the symposium: Advanced Manufacturing, AI and Materials Discovery, Biomaterials, Electronic Materials, Energy, Entrepreneurship, Smart Materials, and Sustainability. The31 distinguished speakers, representing academia, industry, and nationallaboratories, shared their unique perspectives. Within this Viewpoint,distinguished speakers have expanded on the symposium’s themes,summarizing key takeaways, identifying critical challenges, and exploringopportunities for continued advancements in polymer science.

Oxidative esterification of aldehydes in alcohols by one step has been of great interest. Gold catalysts are efficiently employed to produce methyl methacrylate (MMA) from methacrolein (MAL) with methanol (MeOH). A series of FexLay-CeOz composite oxides (FLC) were synthesized by impregnation method. Au/FLC catalysts were prepared by depositing Au nanoparticles on FLC using a modified deposition precipitation method. The effect of Fe–La composite oxide (FLO) with different molar ratio of Fe to La on the catalytic performance was detailed investigated. The results of H2-TPR and TEM revealed that the introduction of FLO led to the formation of strong metal–support interaction (SMSI) on the surface of Au/FLC catalyst. XPS, O2-TPD, Raman spectroscopy, and FTIR spectroscopy indicated that Au/FLC surface exhibited enhanced electron transfer and a higher abundance of active oxygen species compared to Au/CeO2. CO2-TPD and NH3-TPD analysis reveal that the incorporation of dopant enhances the abundance of strong basic sites in the catalyst. Au/FLC catalyst exhibited high activity under across various substrate concentrations especially in base-free environment. When the molar ratio of Fe to La was 1:1 as well as Au/MAL = 0.05 mol %, the conversion of MAL reaches 97.5%, the selectivity of MMA is 95.3%, and the turnover frequency (TOF) achieved at 487.5 h–1 with optimal performance. The excellent activity of Au/FLC can be attributed to the abundant active oxygen species and basic sites on its surface. The kinetics of gas–liquid–solid heterogeneous catalytic oxidative esterification reactions were studied. Additionally, a possible reaction mechanism was proposed.

This paper presents an advanced two-stage nanocomposite membrane system designed to efficiently separate and capture methane (CH4) and carbon dioxide (CO2) from atmospheric air and water sources. The membrane system comprises a CO2-selective primary membrane and a CH4-selective secondary membrane, utilizing a hierarchical nanomaterials and polymers structure. The proposed system demonstrates unprecedented versatility, operating effectively across an extensive range of gas concentrations (>20% to <0.02%) and reducing CH4 levels from 100-500 ppm to 5-10 ppm in both aerobic and anaerobic conditions. Performance metrics specify CO2 permeances of 200-2000 GPU and CO2/N2 selectivities of 30-500 at 57 °C and 1 atm feed pressure, surpassing the Robeson upper bound for traditional polymer membranes. The CH4-selective membrane achieves 500-2000 GPU permeances with CH4/CO2 selectivities >50. Furthermore, experimental validation over 1000 hours of continuous operation demonstrated 92% methane capture efficiency under challenging conditions (55 tons/hour methane content at 30 °C). The system's energy consumption of 0.3 kWh/kg of CH4 captured underscores its efficiency compared to traditional methods. This innovative membrane technology offers a promising solution for addressing critical ecological and industrial challenges associated with greenhouse gas emissions in the 21st century.

Abstract Indonesia has the third highest number of tuberculosis (TB) patients infected with Mycobacterium tuberculosis (MTB) Lineage 1 (L1). Most of these MTB L1 cases can be found in Indonesia’s remote easternmost province of Papua, one of Indonesia’s most underdeveloped provinces with a particularly high burden for TB. In this study, we sequenced and described 42MTBL1 isolates from a well-characterized cohort of patients. We found a genetically diverseMTBL1 population with no association between pathogen genetic relatedness and place of residence or pathogen genetic relatedness and patient ethnicity, which could reflect mixing between different locales and ethnicities or our low sampling fraction. Only a small number showed genetic variants associated with drug resistance (5/42, 11.9%), probably due to a lack of effective treatment programs. The Papuan isolates showed similarities to other Island Southeast Asian Countries due to the high proportion of L1.2.1.2.1 (30/42, 71.4%), especially East Timor and the Philippines. This study fills a research gap of MTB L1 in Indonesian Papua and should serve as a stepping stone for further research in the region.

The aim of this study was to evaluate the wettability and adhesion of self-organized TiO2 nanotubes formed on the surface of 8 commercially pure titanium (CP-Ti) disks and 12 dental implants (n = 12) by anodization in a glycerol-H2O (50-50 v/v) electrolyte containing NH4F. Two disk specimens were not submitted to anodization (controls). The nanotubes thus obtained had average dimensions of 50 nm in diameter by 900 nm in length. The treated disk specimens were stored for 2, 14 and 35 days (n = 2), and the wettability of their surfaces was evaluated with a goniometer at the end of each storing period. The adhesion of nanotubes to titanium was evaluated by field emission scanning electron microscopy after subjecting the 12 implants to a simulation of clinical stress in two-part synthetic bone blocks. After installing the implants with the application of an insertion torque, the two halves of the block were separated, and the implants were removed. The nanotubes remained adhered to the substrate, with no apparent deformation. The contact angles after 14 days and 35 days were 16.47° and 17.97°, respectively, values significantly higher than that observed at 2 days, which was 9.24° (p < 0.05). It was concluded that the method of anodic oxidation tested promoted the formation of a surface suitable for clinical use, containing nanotubes with levels of wettability and adhesion to titanium compatible with those obtained by other methods found in the literature. The wettability, however, did not prove stable over the tested storage periods.