Microstructural Changes Research Articles

Towards hybrid protein foods: Heat- and acid-induced hybrid gels formed from micellar casein and pea protein

Given the rising demand for more sustainable, cookable dairy alternatives, this research explores the formation and characteristics of heat- and acid-induced gels combining micellar casein and pea protein. Protein dispersions (4 % w/w) of commercial micellar casein isolate and pea protein isolate were prepared and preheated (95°C, 30 min) separately before mixing in varying ratios (75:25 %, 50:50 %, and 25:75 % w/w). After emulsifying with milk fat (3.5 % w/w), the protein mixtures were heated to 80 °C and acidified to pH 5.2 (citric acid). The resultant coagula were pressed, drained, and molded to obtain the final gel. It was observed that adding pea protein led to a higher yield of coagula with more serum retained. As the proportion of pea protein increased, the total solids (TS), protein, and fat content of the gels decreased linearly. The micellar casein gel showed significantly higher hardness, elasticity, and chewiness than the gels containing pea protein. Moreover, the micellar casein gel did not show clear fracture behavior under large deformation, while the gels containing pea protein were more prone to rupture. These textural differences were explained by the changes in gel compositions, protein interactions, and gel microstructure. The composition and textural properties of hybrid gels showed a strong linear relationship with pea protein fractions, showing the possibility of customizing gel properties. Notably, the hybrid gel containing 25 % pea protein exhibited promising characteristics, closely resembling those of the commercial dairy paneer product.

Investigating the pH-Dependence of gelation process in chitosan-glutaraldehyde hydrogels with diffusing wave spectroscopy

The gel time of functional hydrogels is an essential property that dictates their utility in various applications. To accurately assess this parameter, the chitosan-glutaraldehyde hydrogels were characterized here using two complementary analytical tools, rotational rheometer, and diffusing wave spectrometer (DWS). Rotational rheometers are widely used to continuously monitor the macro-mechanical properties of hydrogels during the gelation process. By observing the modulus change curve, one can gain insights into the instantaneous changes occurring within the gel network. This method provides a direct measurement of the gel's mechanical strength; however, it involves applying external forces to the sample, which may introduce artifacts such as measurement lag and potential sample deformation or destruction. Results of this study indicated that the application of external force during rotary rheometer measurements disrupted the gelation process. In contrast, DWS detected alterations in the microstructure by measuring light diffusion, allowing to track microstructural changes post-crosslinking, and curing without the interference of external stress. Thus, DWS offers a non-invasive approach to studying gelation as it detected the Brownian motion of particles within the hydrogel by monitoring the diffraction of light, thereby providing undisturbed dynamic information about the gel's behavior. The DWS technique is particularly useful for tracking microstructural changes that occur during hydrogel crosslinking and curing, without altering the gel's native state. An additional advantage of DWS is its ability to investigate the pH effect on gelation. By measuring changes in gelation time as a function of pH, we could achieve precise control over the gelation process. This fine-tuning of gelation kinetics is crucial for applications that require rapid or delayed gelation, offering a level of precision that is difficult to match with traditional rheological methods.

Insights into Machining Techniques for Additively Manufactured Ti6Al4V Alloy: A Comprehensive Review

Investigation into the post-processing machinability of Ti6Al4V alloy is increasingly crucial in the manufacturing industry, particularly in the machining of additively manufactured (AM) Ti6Al4V alloy to ensure effective machining parameters. This review article summarizes various AM techniques and machining processes for Ti6Al4V alloy. It focuses on powder-based fusion AM techniques such as electron beam melting (EBM), selected laser melting (SLM), and direct metal deposition (DMD). The review addresses key aspects of machining Ti6Al4V alloy, including machining parameters, residual stress effects, hardness, microstructural changes, and surface defects introduced during the additive manufacturing (AM) process. Additionally, it covers the qualification process for machined components and the optimization of cutting parameters. It also examines the application of finite element analysis (FEA) in post-processing methods for Ti6Al4V alloy. The review reveals a scarcity of articles addressing the significance of post-processing methods and the qualification process for machined parts of Ti6Al4V alloy fabricated using such AM techniques. Consequently, this article focuses on the AM-based techniques for Ti6Al4V alloy parts to evaluate and understand the performance of the Johnson–Cook (J–C) model in predicting flow stress and cutting forces during machining of the alloy.

THE EFFECT OF HEAT-TREATMENT ON THE MECHANICAL PROPERTIES OF EXPANDED GLASS PARTICLE/A356 SYNTACTIC FOAM

This research investigates the manufacturing of metal syntactic foams (MSFs) using a packed bed of porous (2-2.8 mm) expanded glass (EG) within an A356 alloy matrix. To this end, the counter-gravity infiltration casting technique is employed to manufacture the specimens. The density of the MSFs ranges from 1.05 to 1.17 g/cm3, making it one of the lowest densities foams, attributed to the filler particles' low bulk density. The study investigates the influence of T6 heat treatment on the mechanical properties and microstructural characteristics of the manufactured MSFs. The mechanical properties of the MSFs are characterized under quasi-static compressive loads at 1 mm/min. After heat treatment, the compression test results indicate a significant enhancement in most mechanical properties. Compression strength and plateau stress are approximately doubled compared to as-cast foams for samples with similar densities. While energy absorption of the MSFs triples in heat-treated conditions. These improvements are attributed to changes in the matrix microstructure due to thermal treatment. Microstructural analysis reveals that Si particles, initially sharp and continuous within inter-dendritic boundaries, become blurry and discontinuous through spheroidization after thermal treatment. This hinders crack growth in the cell wall and mitigates the effects of casting defects and the columnar dendritic structure. The majority of mechanical properties in both heat-treated (HT) and as-cast (AC) foams exhibited an increase in density due to an increase in the matrix fraction. However, plateau end strain and energy absorption efficiency demonstrated an independent effect of heat treatment and density.

Microstructure and Wear Behavior of AlxCoCuNiTi (x = 0, 0.4, and 1) High-Entropy Alloy Coatings

AlxCoCuNiTi (x = 0, 0.4, and 1) high-entropy alloy coatings on 45 steel substrates were prepared by laser cladding, and their phase structure, microstructure, element partition, and wear behavior were investigated. The results show that the AlxCoCuNiTi (x = 0, 0.4, and 1) coatings have a dual-phase structure of FCC and BCC. With the increase of x from 0 to 1, the content of the FCC phase decreases from 66.9 wt.% to 14.3 wt.%, while the content of the BCC phase increases from 33.1 wt.% to 85.7 wt.%. When x = 0.4, the lattice constants of the two phases are the largest, and their densities are the smallest. The microstructure of the AlxCoCuNiTi (x = 0, 0.4, and 1) coatings is composed of BCC-phase dendrites and FCC-phase interdendrite regions. Ti is mainly enriched in the primary phase or BCC dendrites, Cu is enriched in the interdendrite regions, and Al is enriched in the dendrites. The friction coefficients of AlxCoCuNiTi (x = 0, 0.4, and 1) coatings during wear tests are 0.691, 0.691, and 0.627, respectively. The lowering of the wear friction coefficient when increasing the Al content is mainly related to the change in phase structure, microstructure, and wear mechanism.

Insights of physicochemical structure changes of bituminous coal with acidification-assisted controlled electric pulse through SEM, XRD and FTIR

Controlled electric pulse (CEP) cracking coal effectively enhances its permeability, but a high coal breakdown voltage (BV) can result in technical difficulties. To address this problem, the method of using HCl solution to improve the electrical conductivity of coal was proposed. The effects of HCl on coal BV were investigated, and the microstructural changes in coal were analyzed through scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. Compared with raw coal, the BV of acidified coal decreased significantly. The crushing degree of the coal samples was clearly enhanced with an increasing HCl concentration. Some internal coal minerals were acidified and dissolved, the aromatic layer spacing (d002) increased and the layer sheet stacking height (Lc) decreased, and the crystal structure was damaged. When acidified coal was broken down, numerous internal pores and cracks appeared, active coal groups were shed, the aliphatic hydrocarbons and oxygen-containing functional group contents increased, surface activity was reduced, and the hydroxyl content was reduced, which was conducive to rapid gas desorption. Acidification effectively reduces the BV of coal and improves the cracking and permeability enhancement effect of coal by CEP action.

Free Water MRI of White Matter in Wilson's Disease.

Diffusion tensor imaging (DTI) is susceptible to partial volume effects from free water, which can be corrected by using bi-tensor free water imaging (FWI). This approach may improve the evaluation of microstructural changes associated with Wilson's disease (WD). To investigate microstructural changes in white matter of WD using DTI and FWI. Prospective. Nineteen neurological WD (7 female, 31.68 ± 7.89 years), 10 hepatic WD (3 female, 29.67 ± 13.37 years), and 25 healthy controls (13 female, 29.5 ± 7.7 years). 3-T, spin-echo echo-planar imaging diffusion-weighted imaging, T1-weighted, T2-weighted, fluid-attenuated inversion recovery. Various diffusion metrics, including mean diffusivity (MD), radial diffusivity (RD), fractional anisotropy (FA), axial diffusivity (AD), free water, and free water-corrected metrics (MDT, RDT, FAT, and ADT) were estimated and compared across entire white matter skeleton among neurological WD, hepatic WD, and controls. Voxel-wise tract-based spatial statistics and region of interest (ROI) analysis based on white matter atlas were performed. Additionally, partial correlation analysis was conducted to assess the relationship between FWI indices in ROIs and clinical indicators. One-way analysis of variance, family-wise error correction for multiple comparisons, and Bonferroni correction for post hoc comparisons. A P-value <0.05, corrected for multiple comparisons, was considered statistically significant. Our study found significantly lower FA and higher MD, AD, and RD across most of white matter skeleton in neurological WD. Decreased FAT and increased MDT, ADT, and RDT were observed only in limited white matter areas compared to DTI indices. Additionally, a significant relationship was found between Unified WD Rating Scale neurological subscale of neurological WD and free water (r = 0.613) in middle cerebellar peduncle, ADT (r = -0.555) in superior cerebellar peduncle, RDT (r = 0.655), and FAT (r = -0.660) in posterior limb in internal capsule. FWI may allow a more precise evaluation of microstructural changes in WD than conventional DTI, with FWI metrics potentially correlating with clinical severity scores of WD patients. 2 TECHNICAL EFFICACY: Stage 2.

Effect of Ag, Sn, and SiCN Surface Coating Layers on the Reliability of Nanotwinned Cu Redistribution Lines Under Temperature Cycling Tests.

Nanotwinned Cu (NT-Cu) is a promising candidate for Cu redistribution lines (RDLs). However, oxidation in NT-Cu lines is of concern because it increases electrical resistance and endangers the reliabilities of semiconductor devices such as temperature cycling tests (TCTs). In order to enhance the reliabilities, the passivation of NT-Cu lines is needed. In this study, immersion Ag/Sn and plasma-enhanced chemical vapor deposition (PECVD) SiCN were used to passivate the surfaces of NT-Cu RDLs at low operating temperatures (60 °C for immersion and 150 °C for PECVD). We found that Ag- and SiCN-capped NT-Cu lines showed negligible changes in microstructures and resistance after TCTs. As for Sn-coated NT-Cu lines, the resistance remained stable after 250 cycles of TCTs, with low oxygen signals detected. These three coating layers can block oxygen and moisture, effectively preventing oxidation and maintaining the resistance of NT-Cu RDLs during the TCT. The findings demonstrate the effectiveness of Ag, Sn, and SiCN coatings in enhancing reliability, providing options for passivation layers of NT-Cu RDLs.

Investigating the influence of ferric oxide grade alumino‐silicate cenosphere particulates and heat treatment on the microstructural evolution and mechanical properties of Al6061/ferric oxide alumino‐silicate cenosphere (x weight %) composite

AbstractThe main aim of this investigation is to fabricate aluminum 6061 composites with three different weight percentages of ferric oxide grade alumino silicate cenosphere (1 wt.%, 3 wt.%, and wt.%) by the stir‐casting process. The fabricated cast composite and T6 heat‐treated composite is used to obtain a fundamental understanding of various weight percentages of the cenosphere and the influence of heat treatment on the microstructural changes, mechanical characteristics, the mechanism of fracture, and the interface between the aluminum‐matrix and ferric oxide grade alumino‐silicate cenosphere particulates. Tensile and compressive tests with a constant strain rate (0.5 mm ⋅ min−1) were carried out to study the strength and to find a correlation between the various weight fractions of cenosphere and heat treatment. Investigations of the changes in the microstructure of the aluminum ferric oxide grade alumino silicate cenosphere composite and the fractography of the fracture surface are investigated using optical and scanning electron microscope. X‐ray diffraction was utilized to confirm the results obtained from optical and scanning electron microscope analyses for phase characterization validation. A maximum of 30 % increase in hardness value, 20 % increase in tensile strength value, 33 % increase in maximum compressive strength value, and 2 % increase in elongation values are observed in heat‐treated composite when compared to cast composite.

Spectroscopic Response of Chiral Proteophenes Binding to Two Chiral Insulin Amyloids

AbstractWe recently reported on 8 different pentameric oligothiophenes, denoted proteophenes, with different amino acid substitution patterns along the conjugated thiophene backbone. The proteophenes were forming chiral both molecular (solvent dissolved) and self‐assembled nano‐architectonic structures, the latter having approximately 5–6 times greater ICD responses. Herein, two proteophenes, HS‐84‐E−E and HS‐84‐K−K, were further investigated in terms of binding to two chiral variants of insulin amyloid fibrils. Binding curves based on fluorescence revealed strong primary binding sites for both proteophenes and more unspecific secondary binding for especially the latter. Interestingly, their induced circular dichroism (ICD) responses were similar to or stronger than for their solvent form and showed a complicated alteration upon binding suggesting that the microstructure at the binding site governs the helical structure of the ligand. Hyperspectral fluorescence microscopy and FLIM revealed more details on the molecular binding in terms of proteophene emission decay‐times. Vibrational circular dichroism (VCD) analysis showed that VCD signal of amyloid fibrils was enhanced upon binding of proteophenes, suggesting changes in the amyloid microstructures.

Neuroimaging Correlates with Clinical Severity in Wilson Disease: A Multiparametric Quantitative Brain MRI.

Previous studies have reported metal accumulation and microstructure changes in deep gray nuclei (DGN) in Wilson disease (WD). However, there are limited studies that investigate whether there is metal accumulation and microstructure changes in DGN of patients with WD with normal-appearing routine MRI. This study aimed to evaluate multiparametric changes in DGN of WD and whether the findings correlate with clinical severity in patients with WD. The study enrolled 28 patients with WD (19 with neurologic symptoms) and 25 controls. Fractional anisotropy (FA), mean diffusivity (MD), and magnetic susceptibility in globus pallidus, pontine tegmentum, dentate nucleus, red nucleus, head of caudate nucleus, putamen, substantia nigra, and thalamus were extracted. Correlations between imaging data and the Unified Wilson's Disease Rating Scale (UWDRS) neurologic subitems were explored. FA, MD, and susceptibility values were higher in multiple DGN of patients with WD than controls (P < .05). Patients with WD without abnormal signals in DGN on routine MRI also had higher FA, MD, and susceptibility values than controls (P < .017). We found that UWDRS neurologic subscores correlated with FA and susceptibility values of DGN (P < .05). In addition, we also found that FA and susceptibility values in specific structures correlated with specific neurologic symptoms of WD (ie, tremor, parkinsonism, dysarthria, dystonia, and ataxia) (P < .05). Patients with WD have increased FA, MD, and susceptibility values even before the lesion is morphologically apparent on routine MRI. The increased FA and susceptibility values correlate with clinical severity of WD.

Controlling titanium incorporation in hydrogenated amorphous carbon films via closed-loop feedback in reactive high power impulse magnetron sputtering

A closed-loop feedback approach has been developed to control titanium incorporation in hydrogenated amorphous carbon (a-C:H) films during reactive high-power impulse magnetron sputtering (R-HiPIMS). The average discharge current measured at the magnetron target is used as the primary feedback signal to regulate the target coverage state. Hence, the titanium concentration in the films can be controlled. Significant changes were observed in the film microstructure and properties as the target state evolved with increasing target coverage. This causes the film transition from metallic titanium to a-C:H films with decreasing titanium concentration. For example, the XRD and Raman analyses indicated a microstructural change from hexagonal titanium to cubic titanium carbide and finally to amorphous carbon. The change in microstructure aligned with the density decreasing from 4.7 g∙cm‒3 to 1.6 g∙cm‒3 measured by XRR technique. In addition, a decrease in the Ti/C atomic ratio, from 1.53 to 0.03, clearly demonstrates that the titanium content can precisely be controlled. A simplified model was proposed to explain the relationship between the average HiPIMS current and the carbon coverage fraction on the target surface. The suggested relationship clarifies how adjusting the average discharge current effectively regulates the target coverage state and the consequent titanium concentration. The approach not only enhances process stability, but also offers an alternative to traditional control techniques during the deposition process.

Research Progress towards the Machining of Titanium Alloy Using CNC Milling: A Technical Review

Because of their extraordinary qualities, titanium alloys are very sought-after materials that can be applied to a wide range of sectors. Excellent mechanical and chemical qualities, including a high strength-to-weight ratio and resistance to corrosion, are present in it. The special properties of these alloys make machining them extremely difficult. As frequent tool wear occurs throughout the machining process, Computer Numerical Control (CNC) milling has become a potential method for machining titanium alloys due to its precision and versatility. This review article provides a comprehensive overview of the development of titanium alloy CNC milling, with an emphasis on the effects of cutting tool geometries and materials on machining efficiency. The process examines several aspects of cutting circumstances, including depth of cut, speed, feed rate, and lubrication techniques, and optimizes machining parameters and procedures to achieve the best results. Surface integrity and quality, surface roughness, residual stresses, and microstructural changes brought about by CNC milling are the main points of evaluation.

Estimation of Quality of Seam Welds in AlMgSi(Cu) Extrusion by Using an Original Device for Weldability Testing.

Extrusion welding of AlMgSi(Cu) alloys is carried out by using porthole dies, as a result of which hollow shapes are formed with longitudinal seam welds. In the case of the inappropriate selection of the chemical composition of the aluminium alloy or improper metal welding conditions, the weld may have reduced strength in relation to that of the base material, thus weakening the strength of structures based on aluminium extrudates. The prediction of metal welding conditions, depending on the chemical composition of the alloy, the temperature and the unit welding pressures, effectively supports the design of porthole dies, thus significantly reducing the number of necessary extrusion tests and die geometry corrections needed during its implementation in industrial practice, and consequently significantly reducing production costs. In this work, an original laboratory test device simulating the behaviour of metal in a welding chamber of a porthole die was applied to examine the ability of AlMgSi(Cu) alloys to produce high-quality joints. Two different chemical compositions of AlMgSi(Cu) aluminium alloys differing in Mg, Si and Cu contents were used: alloy no. 1A (0.68% wt. Mg, 1.04% wt. Si, 0.61% wt. Cu) and alloy no. 3A (0.8% wt. Mg, 1.21% wt. Si, 1.22% wt. Cu). The weldability tests were carried out under various welding temperatures of 450, 500 and 550 °C and under various welding pressures of 150 MPa, 250 MPa and 350 MPa. The microstructural changes in the produced welds were evaluated with the use of OM and SEM/EDS with chemical analysis in micro-areas, whereas the mechanical effects were evaluated by using a static tensile test. Samples after static tensile testing were subjected to fractographic tests to determine the nature of the fractures. The highest values of relative weld strength were obtained under the highest welding temperature of 550 °C and the highest unit welding pressure of 350 MPa: 87% for alloy number 1/1A (high-strength weld), and 62% for alloy number 6/3A (medium-strength weld). Finally, the extrusion tests were performed in industrial conditions with an examination of the EBSD structure and strength of the longitudinal welds. High values of relative weld strength for extrudates from alloy no. 1/1A and alloy no. 3A, 96% and 89%, respectively, were found, which confirmed the previous weldability testing results.

On the work-hardening behaviour of the additively manufactured Al-Si-Mg alloys: Composite-like versus networked microstructure

Al-Si-Mg alloys are widely used for manufacturing components via laser powder bed fusion in various industrial applications where ductility and the capacity to accommodate the strain hardening are key criteria. The ductility of the laser powder bed-fused Al alloys has become a crucial property due to their fine cellular microstructure. Post-processing heat treatments improve ductility, but resultant microstructural changes affect the work-hardening behaviour, deformability, and uniform elongation values. This study aims to investigate the work-hardening capability, uniform elongation and deformability of AlSi7Mg and AlSi10Mg samples after different post-processing heat treatments by using tensile tests, optical and scanning electron microscopies. At aging temperatures below 200 °C, the fully cellular structure of eutectic Si governs both the work-hardening behaviour and the strengthening mechanisms, despite the precipitation phenomenon. When direct-aging temperatures exceed 200 °C, the coarsening of the Si-eutectic network modifies work-hardening behavior (Stages 1–3), accentuating the effects induced by the precipitates. Artificial aging highlights the role of precipitates in controlling both work-hardening properties and deformability.

Precisely tuning ε′-negative and ε′-near-zero responses by synergistic effect of graphene and carbon black in ternary metacomposites

Understanding how to precisely regulate the magnitude and dispersion characteristics of radio-frequency (RF) ε’-negative and ε’-near-zero (ENZ) responses presents a challenge. This challenge significantly impacts the design of versatile electronic devices. In this study, we introduce a synergistic strategy utilizing graphene (GR) and carbon black (CB) in ternary metacomposites for tunable ε’-negative and ENZ responses. Due to the randomly constructed 3-dimensional (3D) conductive GR-CB networks in a CaCu3Ti4O12 matrix, we observed two types of ε’-negative response mechanisms: electric dipole resonance and low-frequency plasma oscillation, which dominate at different frequency bands. Consequently, the weakly ε’-negative values (0 < |ε’| 〈1000) and frequency dispersion were successfully adjusted due to the interplay between these two mechanisms. The ENZ frequencies were also tuned over ∼580 MHz, 225 MHz, ∼189 MHz and ∼ 188 MHz with variable GR-to-CB ratios. Furthermore, we studied the conduction behavior, loss mechanism, and electrical characteristics of the ε’-negative metacomposites to shed light on the relationship between microstructural changes and dielectric performance.

Exploring the multi-scale evolution mechanism of the ultra-high-temperature mechanical behaviour of carbon/carbon composites

The microstructure and mechanical properties of Carbon/Carbon (C/C) composites were investigated after ultra-high-temperature heat treatment (HTT) in the range of 30 – 2950 °C. The evolutionary mechanisms of the mechanical behaviour were explained at three scales: graphene sheets, carbon fibre (CF) monofilaments and the C/C composites. The results displayed that the tensile strength of CF monofilaments decreases monotonically as the HTT increases, while C/C composites present a tendency to decrease and then increase, demonstrating that CF/matrix interfacial properties play a decisive role in the tensile properties. Obvious microstructure change of C/C composites after HTT at 2700 °C was observed, meanwhile the high temperature tensile strength (measured at 2000 °C and 2500 °C) for the composites treated at temperature beyond 2600 °C was higher than that of room temperature. The high-temperature mechanical properties of C/C composites were regulated by the competing mechanisms of the graphite crystallite structure and the skin-core structure of CF monofilament, the CF/matrix interfacial strength and the porosity of C/C composites.

Relationship between regional volume changes and water diffusion in fixed marmoset brains: an in vivo and ex vivo comparison

Ex vivo studies of the brain are often employed as experimental systems in neuroscience. In general, brains for ex vivo MRI studies are usually fixed with paraformaldehyde to preserve molecular structure and prevent tissue destruction during long-term storage. As a result, fixing brain tissue causes microstructural changes and a decrease in brain volume. Therefore, the purpose of this study was to investigate the regional effect of brain volume and microstructural changes on the restricted diffusion of water molecules in the common marmoset brain using in vivo and ex vivo brains from the same individual. We used 9.4T magnetic resonance imaging and also compared the T2-weighted images and diffusion-weighted imaging (DWI) data between in vivo and ex vivo brains to investigate changes in brain volume and diffusion of water molecules in 12 common marmosets. We compared fractional anisotropy, mean diffusivity, AD (axial diffusivity), and radial diffusivity values in white matter and gray matter between in vivo and ex vivo brains. We observed that AD showed the strongest correlation with regional volume changes in gray matter. The results showed a strong correlation between AD and changes in brain volume. By comparing the in vivo and ex vivo brains of the same individual, we identified significant correlations between the local effects of perfusion fixation on microstructural and volumetric changes of the brain and alterations in the restricted diffusion of water molecules within the brain. These findings provide valuable insights into the complex relationships between tissue fixation, brain structure, and water diffusion properties in the marmoset brain.

Magnetic resonance diffusion tensor imaging for detecting the cerebral microstructure changes in patients with CSVD -induced mild cognitive impairment.

Cerebral small vessel disease (CSVD)-induced mild cognitive impairment (MCI) has been linked to cognitive decline. Brain atrophy is considered the most common change in MCI patients, which can be measured by diffusion tensor imaging (DTI). The study aimed to explore the relationship between DTI parameters and cognitive function in CSVD patients with MCI. This retrospective analysis involved 185 patients with CSVD, comprising 87 cases with MCI and 98 cases without MCI (NMCI). Analyses of demographic and clinical characteristics were conducted. DTI-measured fractional anisotropy (FA) and mean diffusivity (MD) in the hippocampus and entorhinal cortex regions were examined. The diagnostic values were determined using receiver-operative-curve (ROC) analysis, with the Youden Index identifying optimum sensitivity and specificity. Correlations between Montreal cognitive assessment (MoCA) scores and FA or MD in MCI patients were further assessed. No significant differences were observed in demographic and clinical characteristics between MCI and NMCI groups (all p>0.05), except for diabetes prevalence (p=0.011). Notably, the ROC analysis highlighted the diagnostic potential of FA, showing the maximum area under the curve values (Hippocampus-Left: 0.76; Hippocampus-Right: 0.66; Entorhinal cortex-Left: 0.62; Entorhinal cortex-Right: 0.64). MD exhibited a significant negative correlation with MoCA scores (Hippocampus-Left: r=-0.58, p<0.001; Hippocampus-Right: r=-0.41, p<0.001; Entorhinal cortex-Left: r=-0.49, p<0.001; Entorhinal cortex-Right: r=-0.27, p<0.001), while FA showed a significant positive correlation (Hippocampus-Left: r=0.51, p<0.001; Hippocampus-Right: r=0.31, p=0.004; Entorhinal cortex-Left: r=0.35, p<0.001; Entorhinal cortex-Right: r=0.38, p<0.001). The study demonstrates the diagnostic value of DTI parameters in CSVD patients with MCI, emphasizing the associations between microstructural brain changes and cognitive function.

Optimization of the Carbonization Process for the Preparation of High-Grade Needle Coke Based on the Response Surface Method and Microstructure Analysis.

Refined coal tar pitch (RCTP) with a quinoline insoluble (QI) content less than 0.01% was obtained from Wuhai coal tar pitch (CTP), which was used as a raw material to prepare needle coke by carbonization and calcination experiments. In this work, the effects of carbonization time, carbonization temperature, and carbonization pressure on the optical structure of green coke and the microstructure of needle coke were investigated. Meanwhile, the microstructure changes of products were characterized by polarizing microscopy, XRD analysis, Raman analysis, and SEM. The reliable transfer functions between the green coke mesophase content and the investigated factors, as well as the graphitization degree of needle coke, were established based on the response surface analysis method. Furthermore, we provide an operable window for carbonization temperature, time, and pressure, guaranteeing that the content of the green coke mesophase is greater than 90% and the graphitization degree of needle coke is greater than 80%. It can be found that the carbonization temperature has the most significant effect on the mesophase content and graphitization degree of coke. Prolongation of carbonization time is helpful for mesophase molecules to fully grow up, and the directional arrangement, which results in the structure of the coke, is regular. The appropriate carbonization pressure not only ensures that the carbonization reaction system has a certain viscosity but also provides hydrogen free radicals, which is conducive to the formation of drainage optical structure.