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A nanoparticle-based drug delivery system is first established by mesoporous silica encapsulating amino acid–intercalated layered double hydroxide (LDH) to construct nanocomposites AA-LDH@MS. The amino acids including phenylalanine (Phe) and histidine (His) with aromatic groups are intercalated into LDH as the cores Phe-LDH and His-LDH. These nanocomposites AA-LDH@MS display multispaces of the interlayer spaces of LDH and porous channels of mesoporous silica to load drugs. Moreover, amino acid molecules provide the interaction sites to improve effectively loading amounts of drugs. 5-Fluorouracil (5-FU) is used as the cargo molecules to observe the delivery in vitro. The results indicate that the maximum loading amounts of drugs are up to 392 mg/g at 60 °C for 12 h in the nanocomposite Phe-LDH@MS. All the nanocomposites exhibit the sustained release of 5-FU at pH 4 and pH 7.4. The Korsmeyer–Peppas model is used to fit the kinetic plot of the drug release in vitro, which concludes that 5-FU release from AA-LDH@MS belongs to Fickian diffusion.
Sputtered thin films of Ag2ZnSnS4 (AZTS) have shown promising semiconducting properties in spite of the films containing SnS2, SnSx, or ZnS as impurity phases. In this study, reaction pathways were identified to produce single-phase AZTS nanoparticles as precursors for forming dense, single-phase films. The morphology, composition, and phase evolution during nanoparticle formation in an oleylamine-based solvothermal reaction process were determined using surface-enhanced Raman spectroscopy (SERS) and transmission and scanning transmission electron microscope (TEM/STEM). The reaction pathways for AZTS nanoparticles were found to be different from Cu2ZnSnS4 nanoparticles in oleylamine, which may explain the difficulty in creating (Ag, Cu)2ZnSnS4 solid solutions in the nanoparticle synthesis. The single-phase AZTS nanoparticle films have a band gap (2.16 eV) slightly higher than sputtered films, and photoelectrochemical (PEC) measurements demonstrated a current of 0.1 mA/cm2 in K2SO4 solution even as porous nanoparticle films, suggesting the potential of this material in solar energy conversion when converted into a dense film.
The authors have shown recently that the neurite extension by neuronal PC12 cells is greatly impacted by aerogel topography. Indeed, the average neurite length of PC-12 cells grown on aerogels is greater than that in cells cultured on control substrates. Here, the authors report on the first experimental study focused on the design and development of a plasmonic photo-patterning technique for collagen-coated mesoporous aerogel biomaterials. Herein, the authors have produced specific patterns on silica aerogels by performing precise plasmonic photo-patterning on liquid crystal-coated aerogels. The authors report the methodology employed to create a collagen–liquid crystal gel mixture imprinted with precise plasmonic photo-patterns. PC12 cells plated on these patterns did attach and survive and followed the spatial cues of the pattern to align themselves in a similar pattern.
Fabrication of simulated buccal mucosa could minimize sacrificing the animals (rabbits and pigs) to extract buccal mucosa for in vitro testing of buccal formulations. Novel artificial buccal mucosa was fabricated using eggshell membrane, extracted from poultry egg, and bovine submaxillary mucin. Chitosan oligosaccharide (COS)–based blended films were fabricated using solvent casting technique. Patches of equal dimensions were cut precisely from whole film. COS-based blended patches were analyzed for their physicochemical and mechanical properties. These patches, proposed to be used for buccal drug delivery, were tested for their mucoadhesion timing using the artificial mucosal membrane. The COS–PVA–blended patch displayed better mucoadhesion than chitosan oligosaccharide–alginate–blended film with the fabricated simulated buccal mucosa. Novel buccal mucosa mimetic–surface such as the one reported in this research article could prove to be a very useful tool in minimizing the use of excised animal buccal mucosa for mucoadhesion testing of buccal drug delivery formulations. Novel COS-blended films were fabricated as a proposed mucoadhesive buccal drug delivery vehicle.
The new compound (4R)-methyl-3-(1-(4-chlorophenyl)-1H-1,2,3-triazole-4-carbonyl)thiazolidin-4-carboxylate was synthesized by the 1,3-dipolar cycloaddition reaction between (4R)-methyl-3-propionyl-thiazolidin-4-carboxylate (1) and 4-chlorophenylazide using the click chemistry approach. Molecular characterization was carried out by infrared spectroscopy and mass spectrometry. The X-ray powder diffraction study determined that the title compound crystallized in an orthorhombic system with unit-cell parameters a = 20.876 (2) Å, b = 12.111 (1) Å, and c = 6.288 (9) Å. The volume of the unit cell is V = 1589.7 (2) Å3. All measured diffraction maxima were indexed and are consistent with the P2221 space group (No. 17). No detectable impurities were observed.
In this work, the authors report a facile method for the preparation of brush-structured nanocomposites of sulfur–polyaniline–graphene oxide (S–PANI–G) that were used for cathode materials of lithium–sulfur batteries (LSBs). The morphology and structure of composite were studied by x-ray photoelectron microscopy, transmission electron microscopy, scanning electron microscopy, and x-ray diffraction analysis. The nanocomposites exhibited good electrochemical performance involving good rate performance, high capacity, and promising cycling stability. The good performance of S–PANI–G results from the synergistic effect of sulfur, polyaniline, and graphene oxide. The composite and method reported here pave the way for the design and synthesis of novel cathode materials for LSBs.
Polymer electrolyte membrane fuel cells (PEMFCs) provide a renewable source of energy through the redox reaction of hydrogen and oxygen gas; however, operation relies on a costly platinum catalyst layer. This study investigates how electrospun catalyst layers may be employed to increase the surface area:volume ratio for catalysis to optimize PEMFC performance. When preparing electrospinning solutions, several base polymers were evaluated in varying concentrations to optimize fiber formation, with poly(acrylic acid) found to be preferable at a 12 wt% concentration. Ultimately, PEMFCs with electrospun catalyst layers achieved a 108% increase in power output compared to those air-sprayed.
The authors report an unexpected anisotropy in tensile properties of a polycrystalline nickel-base superalloy after hot extrusion. The tensile strength of longitudinal specimens (parallel to extrusion direction) is 170–276 MPa higher than that of the transverse counterparts at the temperature ranging from 25 to 750°C. Microstructural investigation excludes possible causes leading to this phenomenon such as variation in the grain size, texture, and γ′ precipitates in two orientations. However, further transmission electron microscopy observation reveals that plenty of twins uniquely exist in longitudinal tensile samples after deformation which are probably responsible for the mechanical gap between the two orientations.
Research into pyrolysis-based recycling of sheet molding compounds (SMCs) to recover glass fiber for reuse has indicated significant pre-existing tensile strength damage in the shredded recycling input materials. This loss in mechanical durability inherently hurts the value proposition of recycled glass fiber by limiting reuse of the fiber for reinforcement. In this study, the mechanical properties of glass fibers at each step in the first lifecycle of an SMC material are measured to assess the extent of cumulating fiber damage prior to recycling and identify potential causes of this degradation to maximum fiber tensile performance.
The ICDD's Powder Diffraction File™ (PDF®) is a database of inorganic and organic diffraction data used for phase identification and materials characterization by powder diffraction. The PDF has been available for over 75 years and finds application in X-ray, synchrotron, electron, and neutron diffraction analyses. With entries based on powder and single crystal data, the PDF is the only crystallographic database where every entry is editorially reviewed and marked with a quality mark that alerts the user to the reliability/quality of the submitted data. The editorial processes of ICDD's quality management system are unique in that they are ISO 9001:2015 certified. Initially offered as text on paper cards and books, the PDF evolved to a computer-readable database in the 1960s and today is both computer and web accessible. With data mining and phase identification software available in PDF products, and the databases’ compatibility with vendor (third party) software, the 1 000 000+ published PDF entries serve a wide range of disciplines covering academic, industrial, and government laboratories. Details describing the content of database entries are presented to enhance the use of the PDF.
Theoretical calculations and experimental observations show MoTe2 is a type II Weyl semimetal, along with many members of transition metal dichalcogenides family. We have grown highly crystalline large-area MoTe2 thin films on Si/SiO2 substrates by chemical vapor deposition. Very uniform, continuous, and smooth films were obtained as confirmed by scanning electron microscopy and atomic force microscopy analyses. Measurements of the temperature dependence of longitudinal resistivity and current–voltage characteristics at different temperature are discussed. Unsaturated, positive quadratic magnetoresistance of the as-grown thin films has been observed from 10 to 200 K. Hall resistivity measurements confirm the majority charge carriers are hole.
Conventional alloy design based on a single primary element has reached its limits in terms of performance optimization. An alloy design strategy with multi-principal elements has recently been uncovered to overcome this bottleneck. Multicomponent alloys, generally referred to as high-entropy alloys (HEAs), exhibit many promising properties, especially outstanding mechanical performance at cryogenic, ambient, and elevated temperatures. In this article, we focus on precipitation-hardened HEAs, which are potential candidates for next-generation structural materials, especially at high temperatures. The key issues involved include precipitation behaviors, phase stability, and phase control, all of which provide useful guidelines for further development of high-temperature materials with superior performance. In particular, we address the formation of cellular γ′ precipitates at grain boundaries, which is closely related to the embrittlement of HEAs at intermediate temperatures. Critical issues and design strategies in developing HEAs for high-temperature applications are also discussed.