Conventional Route Research Articles

Structural, Microstructural, and Electrical Properties Study of Pb(Sn0.45Ti0.55)O3 Ceramics

We undertook a comprehensive investigation of the the structural, dielectric, and electrical characteristics of Pb(Sn0.45Ti0.55)O3 ceramics prepared using the conventional solid-state route. A meticulous preparation protocol, involving solvating various precursors, was followed by extensive characterization employing X-ray diffraction, scanning electron microscopy, and dielectric studies. The synthesized sample features a single-phase tetragonal structure with P4mm symmetry. Using impedance spectroscopy, electrical transport properties of the polycrystalline Pb(Sn0.45Ti0.55)O3(PST) ceramic were studied in detail. Relaxation and conduction mechanisms of the material were inferred using complex impedance, complex electric modulus, and frequency dependent ac conductivity analysis. Impedance spectroscopy results reveal the range of frequencies in which the grain, grain boundary, and electrode effects are dominant. Above certain temperatures, the imaginary component of impedance (Z//) exhibits some resonant type peaks at different frequencies indicating relaxor nature of the sample. The activation energy obtained for both the relaxation and conduction process indicates the role of doubly-ionized oxygen vacancy in the conduction mechanism of the sample. The dielectric relaxation occurring at low frequency and high temperatures is related to the space charges associated with the ionized oxygen vacancies being trapped at the grain boundaries. The Cole-Cole plots confirm the poly-dispersive nature of dielectric relaxation in the sample.

Pyroclastic Dust from Arequipa-Peru Decorated with Iron Oxide Nanoparticles and Their Ecotoxicological Properties in Water Flea D. magna.

A novel magnetic composite made of Peruvian pyroclastic dust material decorated with maghemite nanoparticles was synthesized and characterized using a variety of analytic techniques. The 13 nm maghemite nanoparticles were grown on the pyroclastic dust using the conventional coprecipitation chemical route. A short-term acute assay was developed to study the ecotoxicological behavior of the water flea, Daphnia magna. A 24 h-lethal concentration (LC50) value equal to 123.6 mg L-1 was determined only for the magnetic composite. While the pyroclastic dust material did not exhibit a lethal concentration, it caused morphologically significant changes (p < 0.05) for heart and tail parameters at high concentrations. Morphologies exposed to the magnetic composite above the 24 h-LC50 revealed less tolerance and significant changes in the body, heart, antenna, and eye. Hence, it affects biomarker growth and swimming. The reproduction rate was not affected by the raw pyroclastic dust material. However, the number of individuals showed a decrease with increasing composite concentrations. The present study indicates the LC50 value, which can be used as a reference concentration for in-situ water cleaning with this material without damaging or changing the Daphnia magna ecosystem.

Ferroptosis targeting natural compounds as a promising approach for developing potent liver cancer agents.

Liver cancer is the second leading cause of cancer-related death worldwide. However, treatment options, including surgical resection, transplantation, and molecular drug therapies, are of limited effectiveness. Recent studies have demonstrated that suppressing ferroptosis might be a pivotal signal for liver cancer initiation, thus providing a new way to combat liver cancer. Ferroptosis is a distinct form of controlled cell death that differs from conventional cell death routes like apoptosis, necrosis, and pyroptosis. It results from intracellular iron overload, which raises iron-dependent reactive oxygen species. This, in turn, leads to the accumulation of lipid peroxides that further result in oxidative damage to cell membranes, disrupt normal functioning, and ultimately speed up the ferroptosis phenomenon. Ferroptosis regulation is intricately linked to cellular physiological processes, encompassing iron metabolism, lipid metabolism, and the equilibrium between oxygen-free radical reactions and lipid peroxidation. This review intends to summarize the natural compounds targeting ferroptosis in liver cancer to offer new therapeutic ideas for liver cancer. Furthermore, it serves as the foundation for identifying and applying chemical medicines and natural chemicals that target ferroptosis to treat liver cancer efficiently.

Multiple relaxation mechanisms in SrBi2Nb2O9 ceramic tweaked by tin and samarium incorporation in assistance with single-step microwave sintering

Non-stoichiometric lead free polycrystalline Sr0.8Sn0.2Bi1.75Sm0.25Nb2O9 (SSBSN) ferroelectric ceramics were synthesized through conventional solid step route method by incorporating ball milling and microwave sintering method. X-ray diffraction along with the Rietveld refinement technique confirms the single-phase orthorhombic structure with A21 crystal symmetry. Additionally, the short-range ordering was confirmed by Raman spectroscopy. Doping induced crystallite size and strain were further calculated from the Williamson-Hall plot, which comes around 150 nm and 1.48 × 10–3 respectively. A plate like morphology with an average grain size of 0.41 μm was confirmed by scanning electron microscopy (SEM). A diffuse type ferroelectric to paraelectric phase transition was recorded at 395 °C, mostly arising due to structural heterogeneity at the inter-ferroelectric phase boundary. The temperature and frequency-dependent dielectric measurement of SSBSN ceramic reveal a Maxwell–Wagner relaxation, with prominent dielectric loss in a low frequency regime perhaps due to the generation of leakage current in the SSBSN system. Frequency dependent ac conductivity indicates the polaron assisted hopping mechanism in SSBSN, which further obeys Jonscher’s formulation. The intra and intergranular contributions to impedance in SSBSN ceramics were probed by the complex impedance spectroscopy (CIS) technique. A non-Debye type relaxation mechanism in SSBSN ceramics was indicated by the Cole–Cole plot, whereas the conduction mechanism and transport properties were briefly studied using modulus spectroscopy.

Bispericyclic Ambimodal Dimerization of Pentafulvene: The Origin of Asynchronicity and Kinetic Selectivity of the Endo Transition State.

The propensity of fulvenes to undergo dimerization has long been known, although the in-depth mechanism and electronic behavior during dimerization are still elusive. Herein, we made an attempt to gain insights into the reactivity of pentafulvene for Diels-Alder (DA) and [6 + 4]-cycloadditions via conventional and ambimodal routes. The result emphasizes that pentafulvene dimerization preferentially proceeds through a unique bifurcation mechanism where two DA pathways merge together to produce two degenerate [4 + 2]-cycloadducts from a single TS. Despite the [6 + 4]-cycloadduct being thermodynamically preferred, [4 + 2]-cycloaddition reactions are kinetically driven. Singlet biradicaloid is involved in through-space 6e- delocalization as a secondary orbital interaction that originates asynchronicity and stabilizes the bispericyclic transition state (TS). The transformation of various actively participating intrinsic bonding orbitals (IBOs) unambiguously forecasts the formation of multiple products from a single TS and rationalizes the mechanism of ambimodal reactions that are rather difficult to probe with other analyses. The changes in active IBOs clearly distinguish the conventional reactions from bifurcation reactions and can be employed to characterize and confirm the ambimodal mechanism. This report gains a crucial theoretical insight into the mechanism of bifurcation, the origin of asynchronicity, and electronic behavior in ambimodal TS, which will certainly be of enormous value for future studies.

Grain structure tailoring strategy for heterogeneous lamella SiCp/2024Al composites with exceptional strength-ductility synergy

In this work, a novel grain structure tailoring strategy using one-stepped planetary ball milling, different from conventional powder metallurgy routes that pre-prepared components with different microstructures and then mixed them up, was implemented to fabricate micro- and nano-sized SiC particles (m- & n-SiCp)/2024Al composites with heterogeneous lamella structure. The controllable transformation from homogeneous to heterogeneous grain structures is achieved via nonuniformly distributed n-SiCps induced local grain refinement. Heterogeneous lamella composites exhibit a superior modulus-strength-ductility synergy of 95.3 GPa in Young's modulus, 750.7 MPa in tensile strength and 4.9 % in uniform elongation, particularly with no less than 145 % and 175 % improvements in ductility and toughness, compared with homogeneous composites. Compressive stress relaxation experiments were conducted to reveal the structural dependence of plastic deformation behaviors. Sustainedly rising hetero-deformation induced (HDI) stress produced by extra geometrically necessary dislocation (GND) accumulation at heterogeneous soft/hard domain interfaces and sequential activation of multiple dislocation mediated mechanisms based on load transfer in heterogeneous lamella composites contribute to the enhanced strain hardening capacity, which offers intrinsic toughening. Also, extrinsic toughening originates from enhanced microcrack multiplication and crack-tip blunting.

Effects of La-Mn co-substitution on the structure and magnetic properties of M-type strontium hexaferrite

Research into enhancing the magnetic properties of permanent ferrite using ion substitution techniques has continued, particularly concerning replacing commercially available La-Co co-substitution ferrite with larger magnetic anisotropy and lower prices. Mn ions with larger magnetic moments have become one of the options. In this work, Sr1-xLaxFe11.6-xMnxO19 (0 ≤ x ≤ 0.5) with equal substitution of La-Mn was synthesized by the conventional ceramic route. X-ray diffraction analyses indicated that the upper limit of La-Mn concentration was 0.4. The lattice constant a increases and c decreases with increasing La-Mn concentrations. With the increase of La-Mn concentrations, Ms reaches the highest value of 80.52 emu/g (x = 0.2) at 300 K. As evidenced by Raman spectroscopy, the substitution sites of Mn ions in the ferrite lattice altered with the substitution concentration, and the substitution tendency was 4f2 > 12 k + 2a > 4f1. In addition, La-Mn substitution affects the inherent magnetic properties such as HA and Tc of the samples, which has a reference for further improvement of permanent ferrites.

Microstructural and electrochemical behaviour of severely surface-deformed 316L steel manufactured by conventional and selective laser melting routes

This study thoroughly examines the influence of conventional and selective laser melting (SLM) routes and surface mechanical attrition treatment (SMAT) on the microstructural and electrochemical properties of 316L steel. Compared to wrought specimens, the SLM specimens exhibit significantly smaller grains (∼41 vs. ∼83 µm) and higher dislocation density (∼7.2 × 1013 vs. ∼3.7 × 1012 m−2). Both specimens show nearly doubled surface hardness after SMAT, with the SLM surface displaying a ∼30 nm grain size and minimal α’ phase. The microstructure significantly influences passivation and corrosion behaviour. The SLM specimens exhibit superior electrochemical characteristics to wrought counterparts in SMATed (0.00299 mmpy) and non-SMATed (0.00771 mmpy) conditions. SMAT effectively eliminates surface porosity, enhancing the passivation and corrosion resistance of SLM steel.

Boron nanoparticles (BNPs) produced by ns-laser ablation in water: synthesis and characterization

Boron nanoparticles (BNPs) are attractive nanomaterials for their employment in many applications, such as neutron detection, boron neutron capture therapy, proton boron capture therapy and nuclear fusion. Depending on the specific application, 10B or 11B isotopes can be used.Nevertheless, there are significant challenges in developing suitable BNPs using both conventional chemical synthesis routes and dry fabrication techniques. In this study we report BNPs directly synthetised in water by pulsed Laser Ablation in Liquid (PLAL). Nanoparticles of elemental boron have been generated by laser ablation of a sintered 10B target in MilliQ water by employing ns laser pulse. The ablation resulted in BNPs and boron target micro-fragments with hydrogen gas and boric acid as by-products. Simple washing steps were used to obtain clean BNPs in water. The BNPs showed a narrow size distribution between 3 and 4 nm and their stability in water was induced by a thin layer of boron oxide surrounds BNPs. The BNPs were fully characterized by the chemical and structural point of view employing several techniques. A discussion on boron chemical reactions during laser ablation in water and after the NPs were released in solution was done.

Morphological and size tuning of biogenic Ag and Au nanoparticles induced by laser irradiation

Since size and shape of the metal nanoparticles (NPs) determine its physical and chemical properties, such could be relevant for specific applications; it is critical to have adequate control over such features. In this work, a facile bottom-up, bio-inspired synthetic route for noble metal nanoparticles (NPs) preparation is presented. Specifically, Ag and Au monometallic nanoparticles were synthesized by bio-reduction with Citrus paradisi (Grapefruit) aqueous extract. Besides, conventional chemical reduction synthesis using NaBH4 and PVP as capping agent was also performed for comparison purposes. Characterization accomplished by UV–vis spectroscopy and electron microscopy over the synthesized nanoparticles shown that, although that unimodal (in the case of Ag NPs) or almost unimodal (Au NPs) size distributions were obtained, thanks to stabilizing effect of the ligand acting-biomolecules present in the extract; and the narrower size distribution in comparison with the conventional chemical synthesis route were observed, several morphologies were found for both metals. In order to modify such features, the obtained noble metal NPs were submitted to pulsed (30 ps, 10 mJ) Nd:YAG laser irradiation process; after that, the spherical shape seems to be the predominant morphology in both metal nanoparticles, whereas the population of particles smaller than 15 nm became increases considerably.

Investigation of Crypthecodinium cohnii High-Cell-Density Fed-Batch Cultivations

Crypthecodinium cohnii is a marine microalga that can accumulate high amounts of polyunsaturated fatty acids (PUFAs) and thus replace conventional routes of fish oil production. They are associated with the destruction of marine resources and multiple downstream/purification complications. The major drawbacks of using C. cohnii for industrial-scale production are associated with low PUFA productivity. One of the means of increasing the PUFA synthesis rate is to maintain the medium component concentrations at optimal values throughout cultivation, thus increasing PUFA production efficiency, which can result in the successful transfer of the process to pilot and/or industrial scale. The goal of the present research was to develop techniques for increasing the efficiency of PUFA production via C. cohnii cultivation. Multiple experiments were carried out to test and fine-tune the cultivation medium composition and oxygen transfer factors. The biomass yields from individual components, yeast extract, sea salts, and glucose amounted to 5.5, 0.65, and 0.61 g·g−1, respectively. C. cohnii cell susceptibility to mechanical damage was experimentally evaluated. Power inputs of &lt;276.5 W/m3 did not seem to promote cell destruction when Pitched-blade impellers were used. The obtained cultivation conditions were shown to be efficient in terms of increasing the biomass productivity and the omega-3 fatty acid content in C. cohnii. By using the applied methods, the maximal biomass productivity reached 8.0 g·L−1·day−1, while the highest obtained biomass concentration reached 110 g·L−1. A steady increase in the concentration of PUFAs during cultivation was observed from the FTIR data.

Evaluation of the subclavicular route for the pectoralis major flap in oral and maxillofacial reconstruction- Our 15 years experience

Purpose: The pectoralis major flap (PMF) is an important reconstructive tool for defects in the head and neck region but excessive bulk and a limited arc of rotation can be problematic. These problems can be addressed by passing the pedicle deep to the clavicle but some authors feel that this modification may compromise the vitality off the flap. In the current article, these problems have been addressed by using a modified method.&#x0D; Patients and methods: During the past 15 years (2000 to 2014) 182 head and neck cancer patients were treated for primary reconstruction following tumor ablation. PMF was modified by passing the pedicle deeply to the clavicle. Following flap harvest, the pedicle was passed in the subclavicular plane for reconstruction.&#x0D; Results: It was possible to increase the average length of PMF to 2.5-3.5 cm compared to the supraclavicular route by using this modification. Minor complications were observed in 9 of 182 cases (5%): Partial flap necrosis occurred in 6 cases and fistula formation was observed in 3 cases.&#x0D; Conclusions: The subclavicular route increases the length and arc of rotation without compromising vascular supply to a higher degree compared to the conventional supraclavicular route. Furthermore, this concept decreases the bulk of the flap pedicle which is functionally and cosmetically favourable.

Formulation and Characterization of Glucosamine Sulphate Potassium Chloride (GSPC) Loaded Emulgel for the Treatment of Osteoarthritis.

Osteoarthritis (OA) is becoming a major medical burden worldwide due to changing lifestyles and aging populations. Osteoarthritis is a disease characterized by a variety of anatomic and physiological changes to joints, including cartilage degradation, bone remodeling, and the formation of osteophytes. These changes cause pain, stiffness, swelling, and limitations in joint function. Glucosamine serves as a fundamental constituent for cartilage, the resilient connective tissue responsible for cushioning joints. Glucosamine Sulphate Potassium Chloride (GSPC) supplementation is widely employed to mitigate symptoms linked to osteoarthritis, a degenerative joint disorder hallmarked by cartilage degradation. Palliative care aims at minimizing pain and disability and improving function, performance, and quality of life. In this study, the emulgel formulation of GSPC was developed and checked for its potential. Currently, OA does not have a definitive treatment. Since conventional dosage forms cannot deliver the active drug content at a predefined target site in a predictable manner throughout the treatment period, a new carrier system is always required. Considering their reduced size, targeting potential, and site specificity, nanocarrier-based approaches could hold an answer to shortcomings associated with conventional routes. Thus, the objective of the current study was to formulate and characterize glucosamine sulphate potassium chloride-loaded emulgel for the treatment of osteoarthritis. Microemulsion of glucosamine sulphate potassium chloride was formulated using a spontaneous emulsification method comprising of oleic acid (oil phase), Tween 80, Tween 20 (surfactant) and PEG 400, Span 80 (co-surfactant), and distilled water (aqueous phase). The microemulsions were evaluated for surface morphology, globule size, poly-dispersibility index (PDI), zeta potential, and viscosity, and the final batch of microemulsions was selected. The optimized microemulsion contained 35% co-surfactant (propylene glycol), 20% surfactant (Tween 20), and 15% oil (oleic acid) and glucosamine sulphate potassium chloride in a dose of 60 mg, which has sufficient drug loading capacity with a droplet size of 182 nm for optimized formulation. The optimized microemulsion formulation was added to gel prepared by Carbopol 934 in a 1:1 (w/w) ratio, leading to the formulation of glucosamine sulphate potassium chloride- containing emulgel. The prepared emulgel was further evaluated for viscosity, drug content, pH, and in-vitro drug release. Emulgel formulation (F6) showed 88% drug release after 6 hours, and it followed the Higuchi model. Glucosamine Sulphate Potassium Chloride (GSPC) is used in the treatment of OA by increasing the production of proteoglycans, which can cause the cartilage to break down. Emulgel formulation (F3) showed 75.41% drug release, and formulation (F6) showed 88% drug release after 6 h. Therefore, it may be concluded that an emulgel of GSPC can be used as a controlled-release dosage form of the drug for local application in OA.

Sr6Y(PO4)5: Nd3+ a novel whitlockite-type phosphor for optical temperature sensing applications: Synthesis and luminescence properties

Active research in science and technology is improving the development of materials that emit infrared light, with the aim of better optical thermometric sensors. In this paper we report the synthesis of a new NIR-emitting phosphate phosphor, Sr6Y(PO4)5:Nd3+ (SYP: Nd3+), at differing concentrations of Nd3+ using a conventional solid-state reaction route. X-ray diffraction analysis showed that the prepared phosphors exhibit a singular phase with a monoclinic whitlockite structure (space group I2/a). SEM images show micrometer-sized particle. FTIR and Raman spectroscopies confirm the presence of PO43− groups in the examined phosphates. Luminescence features, comprising emission spectra, concentration quenching, and fluorescence lifetime, were investigated for the prepared SYP: Nd3+ samples at various Nd3+ doping concentrations. Excited at 808 nm, the phosphors emitted near-infrared light with four distinct bands corresponding to specific Nd3+ transitions from 4F3/2 to (4I9/2,4I11/2 and 4I13/2) and 4F5/2 to 4I11/2, falling within the first and second biological windows (NIR-I and NIR-II). Importantly, Nd3+ emission characteristics are affected by concentration and temperature. The powders' effectiveness as optical temperature sensors using fluorescence intensity ratio (FIR) between coupled and non-coupled levels was researched across 303–473 K, resulting in two distinctive FIR-based temperature sensor strategies employing emissions at 874.8 nm (4F3/2 → 4I9/2) and 956 nm (4F5/2 → 4I11/2) transitions, all within the first biological window for excitation and emission. Using this method, SYP: Nd3+ revealed a notably elevated sensitivity of approximately 1.16 %K−1 at 303 K, surpassing other Nd3+-doped materials when stimulated within the infrared range. These results strongly suggest the prospective applicability of the analyzed material in monitoring the temperature of biological systems.

Microstructure optimization of cold sprayed Ti-6Al-4V using post-process heat treatment for improved mechanical properties

Cold spray is a solid state additive process involving layer-by-layer deposition onto a substrate at supersonic speed. In contrast with conventional additive manufacturing routes, particles remain at temperatures below the melting point. This feature would be beneficial for titanium alloys through limiting oxidation and epitaxial growth of β grains during manufacturing. However, low strength and ductility were reported for as-deposited materials. In this study, pathways were explored to improve the tensile properties of cold sprayed Ti-6Al-4V. Heat treatments of deposits were carried out using different temperatures and cooling rates. In addition, some samples were manufactured using in situ shot peening to reduce porosity. The resulting microstructures and mechanical properties were thoroughly characterized using different techniques. This approach allowed to reach comparable, or even higher, tensile strength and ductility than its conventionally processed counterparts in spite of residual porosity. Microstructural features were analyzed to clarify this behavior and the relationships between microstructure and tensile properties of cold sprayed Ti-6Al-4V deposits. The outcome of this study leads to promising insights into the use of cold spray as an alternative additive manufacturing route for Ti alloys.

Triplex steel powder design to avoid hot cracking in laser-powder bed fusion using computational thermodynamics

High manganese steels offer exceptional combinations of high strength and ductility, resulting in weight reduction when utilized in structural applications. Nevertheless, the conventional manufacturing routes of these steels is hindered by many production problems. Additive Manufacturing (AM) has emerged as a reliable solution to fabricate thin or complex shape compounds using these steel grades. Indeed, several studies have demonstrated the success to fabricate high manganese twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP) steels by laser-powder bed fusion (L-PBF). However, a recent study on a high manganese triplex steel composition has revealed the occurrence of both hot cracking and micro segregation during rapid solidification in L-PBF, highlighting potential processability issues of this family of high alloy steels. In this study, the hot cracking susceptibility of different triplex steels is evaluated, focusing on the impact of the composition on the solidification paths and final microstructures. A Computer Coupling of Phase Diagrams and Thermochemistry (CALPHAD) approach is employed to predict alloy-dependent hot cracking susceptibility so as to establish guidelines for preventing hot cracking and provide insights into alloy design for AM. Microstructural observations are used to determine the accuracy of CALPHAD predictions in terms of elemental segregation, phase formation and hot cracking susceptibility. To this end, scanning transmission electron microscopy is used to evaluate elemental segregation at grain boundaries, while the local distribution of phases and their relative amount is measured by electron backscattered and X-ray diffraction, respectively. Hot cracking susceptibility is experimentally evaluated by measuring the length of cracks (when present) in the cross section of printed specimens.

Non-Aqueous Based HPMC Transdermal Patch of Aceclofenac: In vitro characterization

Background: An effective substitution for conventional administration routes is transdermal medication delivery. The use of transdermal treatments to treat arthritis has increased significantly in recent years. There is a pressing need to develop a new aceclofenac transdermal medication delivery method. Objective: The current study intends to stop aceclofenac from degrading in an aqueous environment in an effort to increase the drug's stability and effectiveness when used therapeutically to treat arthritis. The goal of the current research is to create non-aqueous, hydroxypropyl methyl cellulose-based transdermal patches for aceclofenac that will improve patient compliance, increase therapeutic efficacy, decrease gastrointestinal side effects, and prevent substantial first-pass metabolism. Method: By using a solvent evaporation approach, 18 different aceclofenac transdermal patch formulations, including HPMCK4M, HPMCK100M, and HPMCK15M, were created. The characterization of these prepared transdermal patches was done in vitro. Result: DSC thermograms concluded that there is no interaction between the API and excipients. The mass, weight variation, flatness, moisture content, moisture uptake, folding endurance, thickness, medication content, and swelling tests of these transdermal patches were all assessed. Good in-vitro physicochemical qualities could be seen in all of the improved formulations. The improved transdermal Patch (P13) was chosen for in-vivo investigations based on the findings. Conclusion: In order to increase the stability and effectiveness of aceclofenac during its therapeutic use for arthritis, it can therefore be reasonably inferred that it can be made into nonaqueous transdermal matrix type patches.

Combined Effect of Particle Reinforcement and T6 Heat Treatment on the Compressive Deformation Behavior of an A357 Aluminum Alloy at Room Temperature and at 350 °C

Solid state sintering of cast aluminum powders by resistance heating sintering (RHS), also known as spark plasma sintering or field-assisted sintering technique, creates a very fine microstructure in the bulk material. This leads to high performance material properties with an improved strength and ductility compared to conventional production routes of the same alloys. In this study, the mechanical behavior of an RHS-sintered age-hardenable A357 (AlSi7Mg0.6) cast alloy and a SiCp/A357 aluminum matrix composite (AMC) was investigated. Aiming for high strength and good wear behavior in tribological applications, the AMC was reinforced with a high particle content (35 vol.%) of a coarse particle fraction (d50 = 21 µm). Afterwards, separated and combined effects of particle reinforcement and heat treatment were studied under compressive load both at room temperature and at 350 °C. At room temperature compression, the strengthening effect of precipitation hardening was about twice as high as that for the particle reinforcement, despite the high particle content. At elevated temperatures, the compressive deformation behavior was characterized by simultaneously occurring temperature-activated recovery, recrystallisation and precipitation processes. The occurrence and interaction of these processes was significantly affected by the initial material condition. Moreover, a rearrangement of the SiC reinforcement particles was detected after hot deformation. This rearrangement lead to a homogenized dispersion of the reinforcement phase without considerable particle fragmentation, which offers the potential for secondary thermo-mechanical processing of highly reinforced AMCs.

Electroacupuncture stimulation enhances the permeability of the blood-brain barrier: A systematic review and meta-analysis of preclinical evidence and possible mechanisms.

An important cellular barrier to maintain the stability of the brain's internal and external environment is the blood-brain barrier (BBB). It also prevents harmful substances from entering brain tissue through blood circulation while providing protection for the central nervous system. It should be noted, however, that the intact BBB can be a barrier to the transport of most drugs into the brain via the conventional route of administration, which can prevent them from reaching effective concentrations for the treatment of disorders affecting the central nervous system. Electroacupuncture stimulation has been shown to be effective at opening the BBB in a series of experimental studies. This study systematically analyzes the possibility and mechanism by which electroacupuncture opens the BBB. In PubMed, Web of Science, VIP Database, Wanfang Database, and the Chinese National Knowledge Infrastructure, papers have been published for nearly 22 years aimed at opening the BBB and its associated structures. A comparison of EB content between electroacupuncture and control was selected as the primary outcome. There were also results on vascular endothelial growth factor (VEGF), nerve growth factor (NGF), P-Glycoprotein (P-gp), Matrix Metalloproteinase 9 (MMP-9), and glial fibrillary acidic protein (GFAP). We utilized Review Manager software analysis to analyze correlations between studies with a view to exploring the mechanisms of similarity. Evans Blue infiltration forest plot: pooled effect size of 2.04, 95% CI: 1.21 to 2.87, P < 0.01. These results indicate that electroacupuncture significantly increases EB penetration across the BBB. Most studies have reported that GFAP, MMP-9, and VEGF were upregulated after treatment. P-gp expression decreased as well. Electroacupuncture can open the BBB, and the sparse-dense wave is currently the most effective electroacupuncture frequency for opening the BBB. VEGF plays an important role in opening the BBB. It is also important to regulate the expression of MMP-9 and GFAP and inhibit the expression of P-gp.

Zero-Temperature Coefficient of Resonant Frequency in [(Mg0.6Zn0.4)0.95Co0.05]1.02TiO3.02-Ca0.6(La0.9Y0.1)0.2667TiO3 Ultra-Low-Loss Composite Dielectrics

Investigating the microwave dielectric properties of ceramics prepared through the conventional solid-state route, such as x[(Mg0.6Zn0.4)0.95Co0.05]1.02TiO3.02-(1−x)Ca0.6(La0.9Y0.1)0.2667TiO3, reveals notable characteristics. [(Mg0.6Zn0.4)0.95Co0.05]1.02TiO3.02 shows a permittivity (εr) of approximately 20, a high quality factor (Q × f) ranging between 250,000 and 560,000 GHz, and a temperature coefficient of resonant frequency (τf) of approximately −65 ppm/°C. To enhance the temperature stability, Ca0.6(La0.9Y0.1)0.2667TiO3 featuring a τf value of +374 ppm/°C was incorporated into the [(Mg0.6Zn0.4)0.95Co0.05]1.02TiO3.02 composition. τf demonstrated an increase with rising Ca0.6(La0.9Y0.1)0.2667TiO3 content, reaching zero at x = 0.95. A ceramic composition of 0.95[(Mg0.6Zn0.4)0.95Co0.05]1.02TiO3.02-0.05Ca0.6(La0.9Y0.1)0.2667TiO3, incorporating 3wt.% BaCu(B2O5) as sintering aids, exhibited outstanding microwave dielectric properties: εr~22.5, Q × f~195,000 (at 9 GHz), and τf~0.1ppm/°C, with a sintering temperature at 950 °C. This material is proposed as a prospective candidate for 6G band components and GPS antennas.