Distributions of Deuterated Polystyrene Chains in Perforated Layers of Blend Films of a Symmetric Polystyrene-block-poly(methyl methacrylate).

We have examined the spatial distributions of polymer chains in blend films of weakly segregated polystyrene-block-poly(methyl methacrylate) [P(S-b-MMA)] and deuterated polystyrene (dPS). By fine-tuning the composition (ϕPS+dPS = 63.8 vol %) of the total PS/dPS component and annealing temperature (230 and 270 °C), P(S-b-MMA)/dPS blend films mainly form perforated layers with a parallel orientation (hereafter PLs//). The distributions of dPS in PLs// were probed by grazing-incidence small-angle neutron scattering (GISANS) and time-of-flight neutron reflectivity (ToF-NR). GISANS and ToF-NR results offer evidence that dPS chains preferentially locate at the free surface and within the PS layers for blend films that were annealed at 230 °C. Upon annealing at 270 °C, dPS chains distribute within PS layers and perforated PMMA layers. Nevertheless, dPS chains still retain a surface preference for thin films. In contrast, such surface segregation of dPS chains is prohibited for thick films when annealed at 270 °C.

Development of Novel Lightweight Dual-Phase Al-Ti-Cr-Mn-V Medium-Entropy Alloys with High Strength and Ductility.

A novel lightweight Al-Ti-Cr-Mn-V medium-entropy alloy (MEA) system was developed using a nonequiatiomic approach and alloys were produced through arc melting and drop casting. These alloys comprised a body-centered cubic (BCC) and face-centered cubic (FCC) dual phase with a density of approximately 4.5 g/cm3. However, the fraction of the BCC phase and morphology of the FCC phase can be controlled by incorporating other elements. The results of compression tests indicated that these Al-Ti-Cr-Mn-V alloys exhibited a prominent compression strength (~1940 MPa) and ductility (~30%). Moreover, homogenized samples maintained a high compression strength of 1900 MPa and similar ductility (30%). Due to the high specific compressive strength (0.433 GPa·g/cm3) and excellent combination of strength and ductility, the cast lightweight Al-Ti-Cr-Mn-V MEAs are a promising alloy system for application in transportation and energy industries.

Enhanced Thermoelectric Properties of P-Type Sn-Substituted Higher Manganese Silicides.

This study introduces Sn-substituted higher manganese silicides (MnSi1.75, HMS) synthesized via an arc-melting process followed by spark plasma sintering (SPS). The influences of Sn concentrations on the thermoelectric performance of Mn(Si1-xSnx)1.75 (x = 0, 0.001, 0.005, 0.01, 0.015) are systematically investigated. Our findings reveal that metallic Sn precipitates within the Mn(Si1-xSnx)1.75 matrix at x ≥ 0.005, with a determined solubility limit of approximately x = 0.001. In addition, substituting Si with Sn effectively reduces the lattice thermal conductivity of HMS by introducing point defect scattering. In contrast to the undoped HMS, the lattice thermal conductivity decreases to a minimum value of 2.0 W/mK at 750 K for the Mn(Si0.999Sn0.001)1.75 sample, marking a substantial 47.4% reduction. Consequently, a figure of merit (ZT) value of ~0.31 is attained at 750 K. This considerable enhancement in ZT is primarily attributed to the suppressed lattice thermal conductivity resulting from Sn substitution.

Enhancing the Strength and Ductility Synergy of Lightweight Ti-Rich Medium-Entropy Alloys through Ni Microalloying.

Medium-entropy alloys (MEAs) have attracted considerable attention in recent decades due to their exceptional material properties and design flexibility. In this study, lightweight and non-equiatomic MEAs with low density (~5 g/cm3), high strength (yield strength: 1200 MPa), and high ductility (plastic deformation: ≧10%) were explored. We fine-tuned a previously developed Ti-rich MEA by microalloying it with small amounts of Ni (reducing the atomic radius and increasing the elastic modulus) through solid solution strengthening to achieve a series of MEAs with enhanced mechanical properties. Among the prepared MEAs, Ti65Ni1 and Ti65Ni3 exhibited optimal properties in terms of the balance between strength and ductility. Furthermore, the Ti65Ni3 MEA was subjected to thermo-mechanical treatment (TMT) followed by cold rolling 70% (CR70) and cold rolling 85% (CR85). Subsequently, the processed samples were rapidly annealed at 743 °C, 770 °C, 817 °C, and 889 °C at a heating rate of 15 °C/s. X-ray diffraction analysis revealed that the MEA could retain its single-body-centered cubic solid solution structure after TMT. Additionally, the tensile testing results revealed that increasing the annealing temperature led to a decrease in yield strength and an increase in ductility. Notably, the Ti65Ni3 MEA sample that was subjected to CR70 and CR85 processing and annealed for 30 s exhibited high yield strength (>1250 MPa) and ductility (>13%). In particular, the Ti65Ni3 MEA subjected to CR85 exhibited a specific yield strength of 264 MPa·cm3/g, specific tensile strength of 300 MPa·cm3/g, and ductility of >13%.

Enhancing Mechanical and Corrosion Properties of AISI 420 with Titanium-Nitride Reinforcement through High-Power-Density Selective Laser Melting Using Two-Stage Mixed TiN/AISI 420 Powder.

This study investigates the effect of laser volume energy density (VED) on the properties of AISI 420 stainless steel and TiN/AISI 420 composite manufactured by selective laser melting (SLM). The composite contained 1 wt.% TiN and the average diameters of AISI 420 and TiN powders were 45 µm and 1 µm, respectively. The powder for SLMing the TiN/AISI 420 composite was prepared using a novel two-stage mixing scheme. The morphology, mechanical, and corrosion properties of the specimens were analyzed, and their correlations with microstructures were investigated. The results showed that the surface roughness of both SLM samples decreases with increasing VED, while relative densities greater than 99% were achieved at VEDs higher than 160 J/mm3. The SLM AISI 420 specimen fabricated at a VED of 205 J/mm3 exhibited the highest density of 7.7 g/cm3, tensile strength (UTS) of 1270 MPa, and elongation of 3.86%. The SLM TiN/AISI 420 specimen at a VED of 285 J/mm3 had a density of 7.67 g/cm3, UTS of 1482 MPa, and elongation of 2.72%. The microstructure of the SLM TiN/AISI 420 composite displayed a ring-like micro-grain structure consisting of retained austenite on the grain boundary and martensite in the grain. The TiN particles strengthened the mechanical properties of the composite by accumulating along the grain boundary. The mean hardnesses of the SLM AISI 420 and TiN/AISI 420 specimens were 635 and 735 HV, respectively, which exceeded previously reported results. The SLM TiN/AISI 420 composite exhibited excellent corrosion resistance in both 3.5 wt.% NaCl and 6 wt.% FeCl3 solutions, with a resulting corrosion rate as low as 11 µm/year.

Remarkable Enhanced Mechanical Properties of TiAlCrNbV Medium-Entropy Alloy with Zr Additions.

Most medium entropy alloys (MEAs) exhibit excellent mechanical properties, but their applications are limited because of their high density. This study explores a series of lightweight nonequiatomic Ti65(AlCrNbV)35-xZrx (x = 3, 5, 7, and 10) MEAs with a low density, high strength, and high ductility. To achieve solid solution strengthening, Zr with a large atomic radius was used. In addition, various thermomechanical treatment parameters were adopted to further improve the MEAs' mechanical properties. The density of the MEAs was revealed to be approximately 5 g/cm3, indicating that they were lightweight. Through an X-ray diffraction analysis, the MEAs were revealed to have a single body-centered cubic structure not only in the as-cast state but also after thermomechanical treatment. In terms of mechanical properties, all the as-cast MEAs with Zr additions achieved excellent performance (>1000 MPa tensile yield strength and 20% tensile ductility). In addition, hot rolling effectively eliminated the defects of the MEAs; under a given yield strength, hot-rolled MEAs exhibited superior ductility relative to non-hot-rolled MEAs. Overall, the Ti65(AlCrNbV)28Zr7 MEAs exhibited an optimum combination of mechanical properties (yield strength > 1200 MPa, plastic strain > 15%) after undergoing hot rolling 50%, cold rolling 70%, and rapid annealing for 30 to 50 s (at a temperature of approximately 850 °C) with a heating rate of 15 K/s. With their extremely high specific yield strength (264 MPa·g/cm3) and high ductility (22%), the Ti65(AlCrNbV)28Zr7 MEAs demonstrate considerable potential for energy and transportation applications.

Development of Novel Lightweight Al-Rich Quinary Medium-Entropy Alloys with High Strength and Ductility.

Most high-entropy alloys and medium-entropy alloys (MEAs) possess outstanding mechanical properties. In this study, a series of lightweight nonequiatomic Al50-Ti-Cr-Mn-V MEAs with a dual phase were produced through arc melting and drop casting. These cast alloys were composed of body-centered cubic and face-centered cubic phases. The density of all investigated MEAs was less than 5 g/cm3 in order to meet energy and transportation industry requirements. The effect of each element on the microstructure evolution and mechanical properties of these MEAs was investigated. All the MEAs demonstrated outstanding compressive strength, with no fractures observed after a compressive strain of 20%. Following the fine-tuning of the alloy composition, the Al50Ti20Cr10Mn15V5 MEA exhibited the most compressive strength (~1800 MPa) and ductility (~34%). A significant improvement in the mechanical compressive properties was achieved (strength of ~2000 MPa, strain of ~40%) after annealing (at 1000 °C for 0.5 h) and oil-quenching. With its extremely high specific compressive strength (452 MPa·g/cm3) and ductility, the lightweight Al50Ti20Cr10Mn15V5 MEA demonstrates good potential for energy or transportation applications in the future.

Rapid Fabrication of High-Entropy Ceramic Nanomaterials for Catalytic Reactions.

Although high-entropy alloys have been intensively studied in the past decade, there are still many requirements for manufacturing processes and application directions to be proposed and developed, but most techniques are focused on high-entropy bulk materials and surface coatings. We fabricated high-entropy ceramic (HEC) nanomaterials using simple pulsed laser irradiation scanning on mixed salt solutions (PLMS method) under low-vacuum conditions. This method, allowing simple operation, rapid manufacturing, and low cost, is capable of using various metal salts as precursors and is also suitable for both flat and complicated 3D substrates. In this work, we engineered this PLMS method to fabricate high-entropy ceramic oxides containing four to seven elements. To address the catalytic performance of these HEC nanomaterials, we focused on CoCrFeNiAl high-entropy oxides applied to the oxygen-evolution reaction (OER), which is considered a sluggish process in water. We performed systematic material characterization to solve the complicated structure of the CoCrFeNiAl HEC as a spinel structure, AB2O4 (A, B = Co, Cr, Fe, Ni, or Al). Atoms in A and B sites in the spinel structure can be replaced with other elements; either divalent or trivalent metals can occupy the spinel lattice using this PLMS process. We applied this PLMS method to manufacture electrocatalytic CoCrFeNiAl HEC electrodes for the OER reaction, which displayed state-of-the-art activity and stability.

Open-Cell Tizr-Based Bulk Metallic Glass Scaffolds with Excellent Biocompatibility and Suitable Mechanical Properties for Biomedical Application.

A series of biocompatible high-porosity (up to 72.4%) TiZr-based porous bulk metallic glass (BMG) scaffolds were successfully fabricated by hot pressing a mixture of toxic element-free TiZr-based BMG powder and an Al particle space holder. The morphology of the fabricated scaffolds was similar to that of human bones, with pore sizes ranging from 75 to 250 µm. X-ray diffraction patterns and transmission electron microscopy images indicated that the amorphous structure of the TiZr-based BMG scaffolds remained in the amorphous state after hot pressing. Noncytotoxicity and extracellular calcium deposition of the TiZr-based BMG scaffolds at porosities of 32.8%, 48.8%, and 64.0% were examined by using the direct contact method. The results showed that the BMG scaffolds possess high cell viability and extracellular calcium deposition with average cell survival and deposition rates of approximately 170.1% and 130.9%, respectively. In addition, the resulting TiZr-based BMG scaffolds exhibited a considerable reduction in Young's moduli from 56.4 to 2.3 GPa, compressive strength from 979 to 19 MPa, and bending strength from 157 MPa to 49 MPa when the porosity was gradually increased from 2.0% to 72.4%. Based on the aforementioned specific characteristics, TiZr-based BMG scaffolds can be considered as potential candidates for biomedical applications in the human body.

Construction and characterization of an expressed sequenced tag library for the mosquito vector Armigeres subalbatus.

BACKGROUND: The mosquito, Armigeres subalbatus, mounts a distinctively robust innate immune response when infected with the nematode Brugia malayi, a causative agent of lymphatic filariasis. In order to mine the transcriptome for new insight into the cascade of events that takes place in response to infection in this mosquito, 6 cDNA libraries were generated from tissues of adult female mosquitoes subjected to immune-response activation treatments that lead to well-characterized responses, and from aging, naïve mosquitoes. Expressed sequence tags (ESTs) from each library were produced, annotated, and subjected to comparative analyses. RESULTS: Six libraries were constructed and used to generate 44,940 expressed sequence tags, of which 38,079 passed quality filters to be included in the annotation project and subsequent analyses. All of these sequences were collapsed into clusters resulting in 8,020 unique sequence clusters or singletons. EST clusters were annotated and curated manually within ASAP (A Systematic Annotation Package for Community Analysis of Genomes) web portal according to BLAST results from comparisons to Genbank, and the Anopheles gambiae and Drosophila melanogaster genome projects. CONCLUSION: The resulting dataset is the first of its kind for this mosquito vector and provides a basis for future studies of mosquito vectors regarding the cascade of events that occurs in response to infection, and thereby providing insight into vector competence and innate immunity.

Comparison of different adjuvants of protein and DNA vaccination for the prophylaxis of IgE antibody formation.

A high-molecular-weight mite allergen Der f11 that was hardly purified for immunotherapy was used to develop the DNA vaccine pDf11. We have shown that vaccination of mice with pDf11 induces Th1 responses characterized by suppression of IgE responses. In the present study, effects of different adjuvants on pDf11 were first studied. Mice receiving pDf11 +/- CpG, bestatin, and bupivacaine had better suppression of IgE responses than those receiving pDf11 +/- lipofectin or alum. Bestatin could greatly boost IgG2a responses. Immunomodulating effects of different adjuvants between protein and DNA vaccines were further elucidated. CpG was the best for both protein and DNA vaccines to profoundly suppress IgE responses, but alum, bestatin and lipofectin were useless for rDf11 to induce IgE inhibition. Neither did the combination of rDf11 and pDf11 have further IgE suppression. In conclusion, CpG is the unique adjuvant for the protein vaccine rDf11 to inhibit IgE responses. In contrast, the DNA vaccine pDf11 +/- CpG, bestatin, or bupivacaine induces profound suppression of IgE responses.

Description of the transcriptomes of immune response-activated hemocytes from the mosquito vectors Aedes aegypti and Armigeres subalbatus.

Mosquito-borne diseases, including dengue, malaria, and lymphatic filariasis, exact a devastating toll on global health and economics, killing or debilitating millions every year (54). Mosquito innate immune responses are at the forefront of concerted research efforts aimed at defining potential target genes that could be manipulated to engineer pathogen resistance in vector populations. We aimed to describe the pivotal role that circulating blood cells (called hemocytes) play in immunity by generating a total of 11,952 Aedes aegypti and 12,790 Armigeres subalbatus expressed sequence tag (EST) sequences from immune response-activated hemocyte libraries. These ESTs collapsed into 2,686 and 2,107 EST clusters, respectively. The clusters were used to adapt the web-based interface for annotating bacterial genomes called A Systematic Annotation Package for Community Analysis of Genomes (ASAP) for analysis of ESTs. Each cluster was categorically characterized and annotated in ASAP based on sequence similarity to five sequence databases. The sequence data and annotations can be viewed in ASAP at https://asap.ahabs.wisc.edu/annotation/php/ASAP1.htm. The data presented here represent the results of the first high-throughput in vivo analysis of the transcriptome of immunocytes from an invertebrate. Among the sequences are those for numerous immunity-related genes, many of which parallel those employed in vertebrate innate immunity, that have never been described for these mosquitoes. The sequences and annotations presented in this paper have been submitted to GenBank under accession numbers AY 431103 to AY 433788 (Aedes aegypti) and AY 439334 to AY 441440 (Armigeres subalbatus).