High Dispersion Research Articles

Disruption of the pkac2 gene in Pleurotus ostreatus alters cell wall structures and enables mycelial dispersion in liquid culture.

In this study, we developed a mycelial dispersion strain by disrupting the pkac2 gene in the white-rot fungus Pleurotus ostreatus. pkac2 is a catalytic subunit gene of protein kinase A, which regulates several transcription factors related to cell wall synthesis. Liquid cultures of the Δpkac2 strains showed very high mycelial dispersibility and were visibly different from the wild-type strain (WT). Although growth on agar medium was slower than that of WT, Δpkac2 strains grew faster in liquid culture and had approximately twice the mycelial dry weight of WT after 5 d of culture. Microscopic observations showed that the cell walls of the Δpkac2 strains were thinner compared to WT. The β-glucan content in the cell walls decreased in the pkac2 disruptants, although the transcription levels of β-glucan synthase genes increased. Furthermore, the Δpkac2 strains showed decreased hydrophobicity and stress tolerance compared to WT. These results indicate that disruption of the pkac2 gene in P. ostreatus alters the structure of the cell wall surface layer, resulting in high-density cultures due to mycelial dispersion.

Ligand-Functionalized Organometallic Polyoxometalate as an Efficient Catalyst Precursor for Amide Hydrogenation.

Amide hydrogenation is an important process for producing amines, with the development of efficient heterogeneous catalysts relying on the creation of bimetallic active sites where the two components interact synergistically. In this study, we develop a method for preparing catalysts using ligand-functionalized organometallic polyoxometalates by synthesizing a Rh-Mo organometallic polyoxometalate, [(RhCpE)4Mo4O16] (CpE = C5(CH3)3(COOC2H5)2), with Rh-O-Mo interfacial structures and ethoxycarbonyl-functionalized ligands as a catalyst precursor. The activity of supported Rh-Mo catalysts for amide hydrogenation depend on the precursor used, with [(RhCpE)4Mo4O16] showing the highest activity, followed by [(RhCp*)4Mo4O16] (Cp* = C5(CH3)5), and then RhCl3 combined with (NH4)6[Mo7O24]·4H2O. The catalyst prepared from [(RhCpE)4Mo4O16] effectively hydrogenates tertiary, secondary, and primary amides under mild conditions (0.8 MPa H2, 353-393 K), demonstrating a high activity and selectivity (conversion: 97%, selectivity: 76%) for primary amide hydrogenation under NH3-free conditions. Furthermore, we determine that carbonyl oxygen atoms in CpE ligands contribute to the electrostatic interaction with Al2O3, leading to the high dispersibility of [(RhCpE)4Mo4O16] on the support. We conclude that the high efficiency of [(RhCpE)4Mo4O16] as a catalyst precursor originates from the effective formation of Rh/Mo interfacial active sites, which is assisted by the electrostatic interaction between the CpE ligands and support.

Efficient Hydrodeoxygenation of Lignin-Derived Phenolic Compounds Over Ru-Based Catalyst with Biochar and Al2O3 as Composite Support.

Hydrodeoxygenation (HDO) is a common strategy for upgrading lignin-derived phenolic compounds into high-quality liquid fuels, and the support rational design of HDO catalysts is critical to achieve a good reaction performance. This work proposed a novel Ru-based catalyst with biochar and Al2O3 as composite support. The addition of biochar can enlarge the porous structure, and the addition of Al2O3 can enhance the acid property of the support. By regulating the content of biochar and Al2O3 components, Ru/CA-2 catalyst achieved the best HDO performance of lignin-derived phenolic compounds, with the optimal component balance of 50 %C and 50 %Al2O3. This catalyst possesses the high Ru metal dispersion (1.38 nm particle size) to activate the hydrogen source, the moderate acid property to suppress carbon deposition and the abundant oxygen vacancy to promote substrate adsorption at the same time. 99.9 % conversion of guaiacol is obtained at 230 °C, with 99.9 % selectivity towards cyclohexane. Ru/CA-2 catalyst also has a good recyclability, with no obvious activity loss after five runs. Furthermore, in the application of catalytic lignin-oil HDO, the content of hydrocarbons increase from 10.7 % to 95.7 %, showing great potential on the industrial usage.

Cerium-induced modification of acid-base sites in Ni-zeolite catalysts for improved dry reforming of methane

Dry reforming of methane (DRM) is a promising route to mitigate greenhouse gas emissions by converting CH4 and CO2 into valuable syngas. The present work explores the effect of Ce addition to Ni-based catalysts supported on CBV3020E (ZSM-5) for DRM. The use of Ce as a promoter to tune the acid-base properties of zeolites for DRM is addressed for the first time in detail. While Ce has traditionally been used to improve oxygen storage capacity, this work explores its novel use as a means to enhance surface basicity and promote CO2 adsorption. The samples were prepared by wet impregnation, characterized using N2-sorption, X-ray diffraction, H2-temperature-programmed reduction, temperature-programmed desorption of CO2 and ammonia, and Fourier transforms infrared spectroscopy, and tested for DRM at 800 °C and 42,000 mL/g.h GHSV. Results show that ZSM-5 zeolite can be beneficial in achieving high metal dispersion. The introduction of 2 wt% Ce to Ni5/ZSM-5 increases the concentration of strong basic sites, resulting in improved catalytic performance from 37 % CH4 conversion and 48 % CO2 conversion for Ni5/ZSM-5 to 55 % and 65 % on promoted Ni5Ce2/ZSM-5, respectively. Thus, the best results are observed on Ni5Ce2/ZSM-5 and an optimal H2/CO ratio of 0.84 is achieved in this case. Upon decreasing GHSV to 15,000 mL/g.h, CH4 and CO2 conversions jump to 83 % and 88 %, respectively on Ni5Ce2/ZSM-5. Cerium doping produces more desirable strong basic sites and enhances NiO reducibility. This promotes CO2 adsorption and drives the catalytic reaction towards syngas formation, which eventually results in increased efficiency and improved performance.

Cyclic behavior of beam-to-upright bolted connections: Experimental study of Chilean steel storage racks

In this research an experimental study to assess the cyclic behavior of bolted moment connection in racks structures is performed. The effect of bolt pretension in the response is evaluated. Sixteen full-scale steel rack joint configurations were subjected to cyclic load according to the protocol established in AISC Seismic provisions. The cyclic performance was evaluated in terms of hysteretic response, failure mechanism, energy dissipation, stiffness, and rotation on the components. Two different configurations were studied. The results showed that the steel rack connections using a 70 % of bolt pretension can accommodate a 0.8 My at 0.04 rad of drift angle, while the joints without bolt pretension reached values below 0.7 My at 4 % of rotation. The failure mechanism was controlled by weld fracture at 4 % of the rotation. A high dispersion in the energy dissipation pattern was obtained and a drop in energy dissipation of up to 4 times in all specimens tested for a 4 % rotation was developed. This phenomenon is due to the welding rupture between the beam and the L-connector. A degradation of the secant stiffness reached up to 60 % for 2 % rotation. Finally, the most important effect of bolt pretension on the cyclic response of steel rack connections was achieved in the increase of flexural resistance and rotation developed.

UVIT Study of the MAgellanic Clouds (U-SMAC). II. A Far-UV Catalog of the Small Magellanic Cloud: Morphology and Kinematics of Young Stellar Population

The Small Magellanic Cloud (SMC) is an irregular dwarf galaxy that has recently undergone an interaction with the Large Magellanic Cloud. The young massive stars in the SMC formed in the disturbed low-metallicity environment are important targets in astrophysics. We present a catalog of ∼76,800 far-ultraviolet (FUV) sources toward the SMC detected using the Ultra Violet Imaging Telescope onboard AstroSat. We created an FUV catalog with ∼62,900 probable SMC members which predominantly comprise main-sequence, giant, and subgiant stars. We selected four young populations (Young 1, Young 2, Young 3, and Blue Loop (BL) stars) identified from the Gaia optical color–magnitude diagram to study the morphology and kinematics of the young SMC using this catalog. We detect a clumpy morphology with a broken bar, a shell-like structure, and the inner SMC Wing for the four stellar populations. The eastern region and the northeastern regions are mainly populated by Young 1, 2, and 3 stars. The central region predominantly has the Young 2 and 3 populations, whereas the SW has BL stars, and Young 2 and 3 stars. The 2D kinematic study using proper motion (PM) reveals that Young 2 and 3 populations show two kinematically distinct subpopulations with low and high PM dispersion, whereas the Young 1 and BL stars show two kinematically distinct populations with low dispersion. Our analysis points to a kinematic disturbance along the R.A. direction for stars younger than ∼150 Myr located in the eastern region, with no significant disturbance along the decl.

Catalytic Ammonia Synthesis by Supported Molybdenum Nitride: Insight into the Support Effect

AbstractThe influence of the support on the performance of Mo nitrides has been investigated in ammonia synthesis and decomposition. A series of Mo–N catalysts supported on different materials, namely SiO2 (commercial, SBA‐15), Al2O3, and CeO2, were prepared. The results indicated that, despite the high dispersion of Mo species in all catalysts, large disparities in the activity for ammonia synthesis exist. Initial rates of ∼1208, ∼481, and ∼372 µmol gactive phase−1 h−1 are obtained over 10‐Mo–N/SBA‐15, 10‐Mo–N/SiO2, and 10‐Mo–N/Al2O3 respectively. However, no catalytic activity was registered when Mo species were supported on CeO2. Furthermore, 10‐Mo–N/Al2O3 deactivated after few hours of reaction. The surface composition was studied by means of XPS to probe the origin of the catalytic activity differences, and the results indicated that a range of various oxidation states of Mo was detected depending on the support. The difference in catalytic behavior could not be solely explained by the differences in Mo–N species concentrations. In situ EPR analysis exhibited that the mechanism of MoO3 nitridation could differ depending on the support, leading to the formation of different Mo–N species. The effect of support was, however, not as severe in ammonia decomposition as it was the case of ammonia synthesis.

The synthesis of an efficient titanium-based flame retardant with high dispersibility in polyamide 66

The preparation of high-performance flame retardants specialized for melt-spinning polyamide 66 (PA66) fibers remains a big challenge nowadays. This study has synthesized a highly dispersed, phosphorus-containing titanocene complex, namely Cp2Ti(DBA). The synthesized flame retardant possesses high dispersibility and compatibility in PA66. Flammability tests show that Cp2Ti(DBA) exhibits efficient flame retardancy in PA66. With the addition of 15 wt % of Cp2Ti(DBA) in PA66, a LOI value of 29.9 % is achieved, and the peak heat release rate (PHRR) and total heat release (THR) are reduced by 36 % and 26 %, respectively, as compared to pure PA66. Based on the py-GC MS study and char analysis, Cp2Ti(DBA) shows a dual-phase flame-retardant mechanism. In the gas phase, Cp2Ti(DBA) releases the phosphorus-containing free radicals, which capture the highly reactive free radicals. While in the condensed phase, titanium promotes the phosphaphenanthrene fragments to degrade and retains phosphorus in the form of titanium phosphates, which reinforce the barrier effect and stability of the char layer. This work may provide an efficient flame retardant with promising applications in PA66, especially for the melt-spinning of fibers.

Electrodeposition Decoration of Pd0 on F‐Co(OH)2 Nanoarrays with Intentionally Introduced Pd2+ Species for Efficient Electrocatalytic Hydrodechlorination of 2,4‐Dichlorophenol

AbstractDeveloping a Pd‐based catalyst possessing high efficiency and low mass loading remains a big obstacle for the large‐scale application of electrocatalytic hydrodechlorination (EHDC) of chlorophenols (CPs). Herein, high dispersion Pd nanoparticles imbedded in Pd2+ hydroxide species are decorated on the surface of F−Co(OH)2 nanowire arrays with a newly developed electrodeposition and hydrolysis coupled process. EHDC of 2,4‐dichlorophenol (2,4‐DCP) with the as‐obtained Pd/F−Co(OH)2/NF‐a exhibits superior performance than other control samples in this work and literature reports. A 100 % removal of 2,4‐DCP is accomplished within 120 min, featuring fast reaction kinetics (kobs=5.0×10−2 min−1) and mass activity (MA=22.2 min−1 g−1Pd). Mechanism investigation shows that the intentionally introduced Pd2+ sites play a pivotal role in the adsorption of 2,4‐DCP, while high dispersion of Pd facilitates the generation of active H*, thus promoting the catalytic performance. This work presents a valuable example for designing high‐performance Pd‐based EHDC catalysts by composition tuning.

Failure mechanism and control technology of soft-rock roadways subjected to high structural stress

The prevention and control of deformation and instability in high-stress soft rock roadways hold significant value for ensuring normal mine production and the safety of personnel and equipment. This study focuses on the pedestrian descent from the 11th mining area of the Yindonggou Mine, providing a thorough elucidation of the internal mechanisms leading to large deformation and instability in the roadway. It accounts for the influences of surrounding rock lithology, geological structure, and support measures. Consequently, based on the theory of rock instability, corresponding tunnel repair measures and control strategies were proposed and verified through field application. The results indicate that: (1) High strength dispersion and insufficient support resistance of the expansive weak and fractured surrounding rock sections are critical factors inducing significant deformation in the soft rock roadway of Yindonggou Mine. (2) The primary factor contributing to the large deformation disaster in the Yindonggou Mine roadway is the disturbance caused by proximate coal seam mining, which exacerbates the conflict between the high structural stress in the strata and the low strength of the surrounding rock. High-level stress initially leads to deformation in the weakly supported floor, followed by deformation and instability of the surrounding rock, ultimately culminating in the collapse of the entire roadway section. (3) Soft rock support should be designed with varying schemes tailored to the rock type and structural stress of the surrounding rock in the tunnel. For tunnels with carbon mudstone and expansive soft rock as the main roof and floor components, the support plan should primarily focus on enhancing the support stiffness of the tunnel wall. Conversely, for tunnels where sandstone predominates as the roof and floor material, the support plan should aim to restore the three-dimensional stress state of the surrounding rock and fully utilize its self-supporting capacity. (4) Based on the engineering conditions of pedestrian downhill in No.11 mining area of Yindonggou Mine, a differentiated support scheme is proposed. The feasibility and effectiveness of each support scheme are verified by numerical simulation, so as to provide valuable reference and enlightenment for similar projects.

Synthesis of Raspberry-like PMMA Particles In a Ternary Solvent Mixture with Binary Initiators.

There is continuing interest in the synthesis of raspberry-like polymer particles, among which most of the reports have tended to focus on polymer composite particles, while there are relatively few examples of polymer particles with a single component. In this study, raspberry-like poly(methyl methacrylate)(PMMA) particles were synthesized by a one-step method in a ternary solvent mixture with binary initiators. The effects of different polymerization parameters, including the solvent composition, the initiator composition, the stabilizer component, the polymerization temperature, the stirring rate, and the nature of the monomer, on the morphology and size of the resulting particles were studied. A plausible mechanism for raspberry-like particle formation was suggested based on the monitoring data of the polymerization kinetics. The raspberry-like PMMA particles have a high dispersion stability in a salty aqueous environment.

Analysis of stress-strain curve of POM fiber reinforced concrete

ABSTRACT As a new type of synthetic fiber, polyoxymethylene (POM) fiber has the advantages of high tensile strength, good dispersibility, and high bonding strength with cement interface. It has broad application prospects. However, there is limited research on POM fiber reinforced concrete. In order to provide scientific basis for promoting the application of POM fiber, this paper adopts a combination of indoor experiments and numerical simulations to obtain the axial stress-strain complete curves of POM fiber reinforced concrete with different volume dosages and studies the uniaxial compressive properties of POM fiber reinforced concrete. Finally, the constitutive equation parameters of POM fiber reinforced concrete were fitted using the Guo Zhenhai model, and the optimal fiber content was determined. The results indicate that at a POM fiber content of 1.5 kg/m3, the load-displacement curve exhibits optimal shape with the highest residual strength. With increasing fiber content, compressive stress-strain curve parameters initially increase and then decrease, peaking at 1.5 kg/m3, optimizing the mechanical properties of concrete. POM fiber has minimal impact on initial elastic modulus. Thus, optimal mechanical property enhancement is achieved with 1.5 kg/m3 POM fiber content.

Boosting hydroisomerization of n-hexadecane by designing core-shell bifunctional catalysts with partially blocked micropores

Hydroisomerization of long-chain n-alkanes is an indispensable route for upgrading fossil fuels and lubricant oils to meet the state of art regulations. Precisely regulate the distribution of acidic and metal active sites to suppress unwanted cracking reaction is hitherto a difficult task. In this work, we develop a simple coating-carbonation strategy for constructing novel core-shell bifunctional catalysts, comprising ZSM-22 zeolite core with the partially blocked channels and Pt nanoparticles loaded on the mesoporous SiO2 shell. The unique treatment not only adjusted the distribution of acid sites located within the micropore channels and external surface, but also alter the locations and dispersion of Pt nanoparticles. Owing to the short diffusion lengths, nanoscale distance between acid sites and Pt species, and high metal dispersions, the core-shell bifunctional catalyst exhibits outperformed performance in n-hexadecane hydroisomerization, i.e., the yield of isomerized hexadecane can reach 87.9 %, which is among the relatively high level compared with the previous reported Pt/zeolite counterparts. Moreover, the catalyst also displays excellent stability (no deactivation within 100 h). The disclosed structure-catalysis relationship provides rational reference for designing the synergistic meta-acid active sites in the hydroisomerization of long-chain n-alkanes.

Formation and Segregation of the Ru- and Rh-MgO Solid Solutions.

Structural changes in Ru- and Rh-loaded magnesium oxide (MgO) subjected to thermal treatment were investigated by using X-ray absorption spectroscopy. The thermal treatment of the MgO-loaded Ru and Rh nanoparticles led to the formation of Ru-MgO and Rh-MgO solid solutions, respectively. The valences of Ru and Rh in the solutions were 4+ and 3+, respectively, as determined by the Ru and Rh K-edge X-ray absorption near-edge structure (XANES). The degree of solid solution formation was the highest at 873 and 1073 K in Ru-MgO and Rh-MgO, respectively, as observed in the extended X-ray absorption fine structure and XANES analyses. The nearest neighboring Ru-O and Rh-O bond distances were shorter than the Mg-O bond in MgO. The dispersion of Ru and Rh on the MgO surface, measured by CO adsorption, increased for samples thermally heated at 1273 K, suggesting that the segregation of Ru or Rh from the solid solutions occurred at this temperature. Consequently, a relatively high dispersion was realized in the sample thermally heated to 1273 K. A good correlation was found between the dispersion value of Ru in Ru/MgO and the NH3 decomposition activity.

Pharmaceutical Residues in Sediments of a Coastal Lagoon in Northwest Mexico-Occurrence and Environmental Risk Assessment.

Contamination of marine ecosystems by pharmaceutically active compounds (PhACs) deserves more research since their environmental fate differs from that observed in freshwater systems. However, knowledge remains scarce, especially in semi-arid coastal regions of the Global South. This study investigates the occurrence and distribution of caffeine, carbamazepine, ciprofloxacin, and sulfamethoxazole in sediments from the La Paz lagoon, a coastal system in a semi-arid region of Mexico with inverse estuarine conditions. Samples of superficial sediments (0-5 cm depth) were collected from 18 sampling points distributed through the lagoon, encompassing sites heavily polluted by discharges of municipal sewage and 3 potentially pristine sites far from the urban and peri-urban zones. Also, a 25 cm length sediment core was taken and divided into 1 cm sub-samples to determine the deposition of target PhACs in the sediment bed through time. The extraction of the target PhACs was performed through the accelerated solvent extraction (ASE) technique and quantification was achieved using a validated HPLC-MS/MS analytical method. The concentration of caffeine, carbamazepine, ciprofloxacin, and sulfamethoxazole in superficial sediment oscillated in the range of 1 to 45 ng g-1 (dry weight). The highest mass fraction of target PhACs was detected in sites impacted by wastewater discharges. The caffeine-to-carbamazepine ratio was determined for the first time in marine sediments impacted by wastewater discharges, resulting in values from 4.2 to 9.12. Analysis of the 25 cm length sediment core revealed a high dispersion of caffeine, which was attributed to high water solubility, while antibiotics were predominantly detected in the upper 20 cm of the core. Risk quotients were calculated, observing low risk for caffeine, carbamazepine, and ciprofloxacin, while sulfamethoxazole presented high risk in all the sampling points. PhACs are retained in superficial sediments from a lagoon impacted by wastewater discharges, and the level of impact depends on the properties of the compounds and the TOC content in sediments. Risk assessments should be performed in the future considering the combination of pharmaceuticals and byproducts in marine sediments. This research emphasizes the importance of sewage management in preserving marine ecosystems in semi-arid regions in the Global South.

Polymers marry with carbon nanospheres: A promising strategy to develop high-performance filtrate reducer

Polymeric filtrate reducers have limited uses under high temperature and salinity conditions. The incorporation of nanoparticles to polymeric networks is a popular and effective method for creating high-performance filtrate reducers. However, present nanofillers are costly, have negative environmental consequences, and are difficult or impossible to disseminate. Herein, a simple hydrothermal process using low-cost and renewable glucose as raw ingredients resulted in hydroxy-rich carbon nanospheres (CNs). After modification by acryloyl chloride, the CNs were copolymerized with acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and sodium p-styrene sulfonate. The obtained CNs-doped polymers (CAAS) were able to maintain high viscosity and colloidal stability even after salt contamination and high temperature aging. CAAS-based drilling fluids can tolerate temperatures of up to 240 °C under 30 % NaCl conditions. The API filtration loss (FLAPI) and the high-temperature high-pressure filtration loss (FLHTHP) were 10 and 63.5 mL, respectively. Considering the low-cost and renewable raw materials, high dispersibility and high compatibility of CNs as well as significant improvement in thermal-resistance and salt-tolerance, this work provides a simple yet effective approach to developing high-performance filtrate reducers for complex geological conditions.

Impact of the K and Fe insertion methods in KFeCeZr catalysts on the CO2 hydrogenation to C2/C3 olefins at room pressure

Light olefins, traditionally sourced from petroleum, are currently being investigated through alternative routes, such as CO2 hydrogenation, aligning with CCUS policies. Alkali-promoted Fe-based catalysts have shown promise in coupling reverse water–gas shift and Fischer-Tropsch processes to produce light olefins from CO2 directly. The in-situ generated Fe5C2 phase is commonly associated with the high activity of these catalysts. However, the preparation methods employed can lead to distinct catalyst properties, which considerably impact the performance during the reaction. Here, we investigate different strategies to introduce K and Fe in the KFeCeZr system and correlate catalyst properties with catalytic activity during CO2 hydrogenation at ambient pressure. The catalyst prepared by one-pot precipitation of Fe, Ce, and Zr followed by K impregnation showed the most promising results in terms of conversion and productivity of light olefins. The effective incorporation of Fe in the CeZrOx structure during synthesis was essential for maintaining the high dispersion of metallic Fe particles after reduction, improving reactant chemisorption. Under reaction conditions, this catalyst showed the most remarkable propensity to form iron carbides (FexCy), mainly composed of Fe5C2 phase. In general, this work highlights the impact that the construction steps of a multifunctional catalyst have on the physicochemical properties and, consequently, on the catalytic activity.

Avian Dispersal Ability Shapes Species-Area Relationships on Islands Worldwide.

Island biogeography theory provides key insights into biodiversity patterns across islands species-area relationships and conservation. However, classical island biogeography theory assumes that species are ecologically equivalent in terms of their dispersal ability. We evaluated the role of a key trait (hand-wing index, a proxy for dispersal ability in birds) in shaping species-area relationships of avifauna spanning 6706 species on 3894 islands. High community-weighted mean (CWM) dispersal ability in regional species pools had widespread but context-dependent effects on island species-area relationships. Among island archipelagos at smaller spatial extents, high CWM dispersal ability was associated with steeper species-area relationships. Among zoogeographical realms at larger spatial extents high CWM dispersal ability was associated with shallower species-area relationships and higher local species richness on small islands. Our study reveals that geographic variation in species' dispersal traits has strong effects on island species-area relationships and likely plays an important role in non-neutral community assembly.

Compatibility of the mechanical properties and thermal conductivity by the formation of a secondary phase in AlN ceramics: application of multifractal analysis for the microstructure evaluation

Aluminum nitride (AlN) ceramics exhibiting different secondary phase morphologies were fabricated using pressureless sintering at varying temperatures ranging from 1700-1850 °C, with a 5 mass% Y2O3 sintering additive. Although the thermal conductivity of the AlN ceramics increased as the sintering temperature increased, the bending strength increased below 1800 °C and decreased above 1800 °C. The morphology of the secondary phase in the AlN ceramics demonstrated granular, reticulate, and linear forms in that order of the low sintering temperature. The value of generalized dimensions Dq obtained by multifractal analysis increased below 1800°C and decreased above 1800°C. Higher values of Dq indicated more complex morphology and higher dispersion, corresponding to the observed morphological changes in secondary phase and the increase or decrease in the value of Dq. The sample sintered at 1800 °C had the highest Dq value and the reticulate secondary phase, with a thermal conductivity of 160 W m-1 K-1 and a maximum bending strength of 324 MPa. These results suggest that the morphology of the secondary phase affects the bending strength of AlN ceramics and that the value of Dq may be an indicator of the microstructure that achieves both thermal conductivity and mechanical properties.

Correlation Between Photoreceptor and Vascular Parameters in Diabetic Retinopathy Using Adaptive Optics.

This study aimed to investigate correlations between photoreceptor and vascular parameters in varying stages of diabetic retinopathy (DR) using adaptive optics (AO) imaging. In this single-center, prospective cohort study, 29 participants (46 eyes) were classified into control/mild non-proliferative DR (NPDR), moderate/severe NPDR, and proliferative DR. AO images of photoreceptors and retinal vasculature were analyzed, and Spearman's correlation (ρ) was used to assess relationships between photoreceptor density and vascular parameters. Higher cone density was inversely associated with total vessel (ρ = 0.22, P = 0.03) and lumen diameters (ρ = -0.24, P = 0.01), while higher dispersion was associated with total vessel (ρ = 0.19, P = 0.06) and lumen diameters (ρ = 0.21, P = 0.04). These associations were primarily significant in mild NPDR. No significant correlations were found in advanced DR stages. This study underscores intricate neurovascular correlations in early-stage DR, suggesting these parameters may aid in early disease detection. Further research is needed to understand whether similar correlations exist in advanced DR. [Ophthalmic Surg Lasers Imaging Retina 2024;55:XX-XX.].