Microstructural Patterns Research Articles

Deterioration mechanism of loess from Ili valley region of China under wet and dry cycles: evidences from shear tests

The properties of loess in the Ili region of China are significantly affected by repeated cycles of rainfall and evaporation. It is thus essential to investigate the deterioration mechanism of loess subjected to the wet and dry cycles. This paper employs various methods, including the direct shear and triaxial shear tests, as well as the scanning electron microscopy (SEM), to evaluate the variation patterns of shear strength parameters and microstructure of Ili loess. The direct shear test was conducted on loess samples experiencing a limited number of wet and dry cycles (0, 1, 3, 5, 7, and 9), while the triaxial shear test focused on a more extensive range of wet and dry cycles (0, 1, 3, 10, 20, and 30). In parallel, the alterations in the shear strength parameters of the loess material under different shear tests were also scrutinized. The findings obtained from this research revealed that the shear strength of Ili loess decreased to varying degrees based on the two test methods when they are affected by the wet and dry cycles. Comparing the results with the same number of wet and dry times (0, 1 and 3 times), both the shear strength and cohesion obtained from the triaxial shear test were greater than those from the direct shear test, while the results for the angle of internal friction were reversed. Moreover, the scanning electron microscope tests on Ili loess did indicate that the micro-particle size, pore space, morphology, soil structure, and particle contact mode exhibited the deterioration with different degrees. The micro-structural change is believed to be the main reason for the deterioration mechanism of the shear strength. The research outcomes will enrich the understanding about the loess properties in Central Asia, providing data reference and theoretical basis for engineering construction in these region.

Investigation of laser-patterned biomimetic microstructures on CFRP and AA5052 surfaces to enhance their single-lap bonding strength

This study focused on laser patterning of the biomimetic microstructures of gecko and tree frog patterns on the bonding surface of CFRP and AA5052 to improve their single-lap bonding strength. Laser-patterned biomimetic microstructures produced a rough surface and a superhydrophilic characteristic. A confocal laser microscope, contact angle measurement equipment and Fourier transform infrared spectroscopy were utilized to examine the surface roughness, wettability characteristic, and chemical bond of CFRP and AA5052, respectively. After the 8-week aging test, the lap shear strength of the test samples without pattern and with gecko and tree frog patterns was 2.22 ± 0.82 MPa, 9.26 ± 0.29 MPa, and 8.56 ± 0.15 MPa, respectively, which decreased approximately 75.8 %, 10.96 % and 13.09 % compared to the unaging tests, respectively. The biomimetic microstructures of laser-ablated gecko patterns were helpful in enhancing the bonding strength of heterogeneous materials and in resisting drastic changes in the environment.

Different impulse control disorder evolution patterns and white matter microstructural damage in the progression of Parkinson's disease.

The course of impulse control disorders (ICD) varies in the early stage of Parkinson's disease (PD). We aimed to delineate the association between the evolution pattern of ICD and the progression of PD. A total of 321 de novo PD patients from the Parkinson's Progression Markers Initiative database were included. Patients were followed up for a mean of 6.8 years and were classified into different groups according to the evolution patterns of ICD. Disease progression was compared among groups using survival analysis, in which the endpoint was defined as progression to Hoehn and Yahr stage 3 or higher for motor progression and progression to mild cognitive impairment for cognitive decline. In the fourth year of follow-up, four types of ICD evolution patterns were identified: (1) non-ICD-stable (68.2%), a patient who is consistently free of ICD; (2) late-ICD (14.6%), ICD developed during the follow-up of patients; (3) ICD-stable (11.5%), patients showed persistent ICD; and (4) ICD-reversion (5.6%), baseline ICD disappeared during the follow-up of patients with ICD. The ICD-reversion type shows daily life non-motor symptoms [Movement Disorder Society-Unified Parkinson Disease Rating Scale (MDS-UPDRS) part I], daily life motor symptoms (MDS-UPDRS part II), rapid eye movement sleep behavior disorder, and anxiety symptoms has a greater impact. PD patients with different ICD evolution patterns had different changes in white matter microstructure at the onset of the disease. Those relevant brain regions are involved in ICD and non-motor functions. Four early ICD evolution patterns are identified in de novo PD, with different prognoses and brain white matter microstructural damage patterns, and they may predict motor progression and cognitive decline in PD patients.

Stability prediction and optimization of multi-regenerative weak stiffness grinding system based on microstructured tool

Chatter is a serious problem in grinding, which will directly affect machining accuracy, efficiency, tool wear and even damage machine tools. In order to understand and avoid grinding chatter, a stability prediction and optimization method of multi-regenerative weak stiffness grinding system based on microstructured tool is innovatively proposed. It is the first time to use microstructured tools to ensure the system stability without sacrificing the material removal rate, which offers promise for weak stiffness grinding. Firstly, a multi-random geometric model of microstructured grinding wheel is established, considering the shape, distribution, microstructure patterns and truing conditions of abrasive grains. On this basis, considering the regulating effect of microstructure patterns on workpiece regeneration delay and tool wear delay of grinding system with large aspect ratio, a multi-regeneration stability model based on microstructure tool is established. Then, the experiments of grinding wheel microstructuring, internal thread grinding and profile measurement are carried out. The results show that the theoretical model established can accurately predict the grinding stability boundaries. The microstructure types can be arranged in descending order according to the optimization degree of grinding chatter: composite type, cross type, oblique type and linear type. Compared with the grinding wheel without microstructures, the microstructured grinding wheel can increase the speed limit deviation by 12.2 % − 54.0 %, which basically solves the chatter problem at high rotation speed. The wear resistance of microstructured grinding wheel is improved by 44.2 %, the tooth profile angle error and bottom fillet radius of workpiece are reduced by 92.3 % and 90.4 % respectively, and the maximum tooth height difference and average tooth height error are reduced by 90.6 % and 87.5 % respectively.

Examining the overlap between patterns of tau deposition and cortical neurite microstructure in preclinical Alzheimer’s disease

AbstractBackgroundIncreased Amyloid‐beta (Aβ) is associated with the neuropathological features of Alzheimer’s disease (AD), and it has been suggested to amplify tau spreading in the brain that leads to neurodegeneration. However, little is known about how the pattern of tau spreading overlaps with that of cortical microstructural neurodegeneration in the preclinical stages of the disease. Here, we utilized molecular imaging and neurite orientation dispersion and density imaging (NODDI) to identify the spreading pattern of tau pathology with the disease progression in cross‐sectional data and interaction with the degradation of cortical neurite microstructures.MethodsThe study consisted of normal controls (CN) and patients with mild cognitive impairments (MCI) from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) (Table 1). All participants had structural and multi‐shell diffusion magnetic resonance imaging (MRI), and positron emission tomography (PET) scans using 18F‐florbetapir (AV45) for and 18F‐flortaucipir (AV1451) for tau. The preprocessed PET images were used to generate the standardized uptake value ratio (SUVR) values in each hemisphere consisting of 180 cerebral cortical brain regions defined by the Glasser atlas. The preprocessed dMRI data were used to compute cortical NODDI coefficients (neurite density (intracellular volume fraction; ICVF), orientation dispersion index (ODI), and isotropic volume fraction (FISO)). The tau and NODDI microstructural values are then normalized compared to the Aβ− CN group by adjusting the values for age and sex. The tau spreading order was defined based on the frequencies of the normalized tau values that exceeded the given threshold and compared the patterns with the neurite microstructures.ResultsWe found a sharp increase of tau deposition in patients with Aβ+ MCI, and the medial temporal regions were identified as the earliest region to become tau positive and continue to spread to inferior temporal and inferior parietal regions. Most importantly, we found significant patterns of cortical ODI degradation with the tau spreading in the right entorhinal cortex (p = 0.004) and the right hippocampus (p = 0.02).ConclusionThe findings of this cross‐sectional study provide that regional cortical neurite imaging could provide higher sensitivity to changes in the pathological process of tau spreading in tau epicenters in AD.

Radiation-Driven Polymerisation of Methacrylic Acid in Aqueous Solution: A Chemical Events Monte Carlo Study.

This study employed a coarse-grained Monte Carlo (MC) simulation to investigate the radiation-induced polymerisation of methacrylic acid (MAA) in an aqueous solution. This method provides an alternative to traditional kinetic models, enabling a detailed examination of the micro-structure and growth patterns of MAA polymers, which are often not captured in other approaches. In this work, we generated multiple clones of a simulation box, each containing a specific chemical composition. In these simulations, every coarse-grained (CG) bead represents an entire monomer. The growth function, defined by the chemical behaviour of interacting substances, was determined through repeated random sampling. This approach allowed us to simulate the complex process of radiation-induced polymerisation, enhancing our understanding of the formation of poly(methacrylic acid) hydrogels at a microscopic level; while Monte Carlo simulations have been applied in various contexts of polymerisation, this study's specific approach to modelling the radiation-induced polymerisation of MAA in an aqueous environment, utilising the data obtained by quantum chemistry modelling, with an emphasis on micro-structural growth, has not been extensively explored in existing studies. This understanding is important for advancing the synthesis of these hydrogels, which have potential applications in diverse fields such as materials science and medicine.

Investigation on physico-mechanical properties and microstructural evolution patterns of heated granite after liquid nitrogen cooling

Liquid nitrogen (LN2) fracturing is recognized as an innovative reservoir enhancement technique, demonstrating significant potential in establishing high permeability pathways in geothermal development. Understanding the physico-mechanical properties and microscopic mechanisms of hot dry rock post LN2 cooling treatment is pivotal for promoting the effective deployment of LN2 fracturing. This study undertook physical and mechanical testing on a quintessential hot dry rock type-granite-post various temperature and LN2 cooling treatments. Subsequently, a multi-scale investigation was conducted on the thermal fracture-pore structure's morphological features and the evolution of mineral components. The experimental findings indicated that LN2 cooling exerts a pronounced impact on the physico-mechanical properties of high-temperature granite. Temperature-induced damage to granite can be delineated into three phases: initial phase up to 200 °C where its effects are relatively imperceptible; an intermediate phase from 200 to 500 °C characterized by gradual deterioration; and a pronounced degradation phase evident at 600 °C. Correlations between the changes in the micro pore-fracture structure of granite and its physico-mechanical property degradation were subsequently established. As temperature escalated, the area of micro-defects in the CT-reconstructed spatial distribution increased progressively. The volumetric porosity damage ratio and fractal dimensions were quantitatively introduced to characterize the fractal geometric features and distribution patterns of internal thermal fractures in granite post thermal shock. Concurrently, NMR experiments indicated that with the escalation of temperature, micropore develop and interlink to form mesopore and macropore, enhancing rock porosity connectivity. These macropores significantly influence granite's physico-mechanical and permeability characteristics. A mineral stability analysis revealed that various minerals undergo physico-chemical reactions, such as dehydration, phase transitions, decomposition, and chemical bond fractures at elevated temperatures, altering mineralogical composition and mineral strength, thus impacting the rock's macroscopic properties. Ultimately, the study delved into the damage mechanisms of granite's physico-mechanical properties from both heating and cooling perspectives during various temperature phases. The insights garnered from this investigation offer novel value in comprehending the thermal damage characteristics induced by LN2 cooling.

Optimizing Fast Charging and Wetting in Lithium-Ion Batteries with Optimal Microstructure Patterns Identified by Genetic Algorithm

To sustain the high-rate current required for fast charging electric vehicle batteries, electrodes must exhibit sufficiently high effective ionic diffusion. Additionally, to reduce battery manufacturing costs, wetting time must decrease. Both of these issues can be addressed by structuring the electrodes with mesoscale pore channels. However, their optimal spatial distribution, or patterns, is unknown. Herein, a genetic algorithm has been developed to identify these optimal patterns using a CPU-cheap proxy distance-based model to evaluate the impact of the added pore networks. Both coin-cell and pouch cell form factors have been considered for the wetting analysis, with their respective electrolyte infiltration mode. Regular hexagonal and mud-crack-like patterns, respectively, for fast charging and fast wetting were found to be optimal and have been compared with pre-determined, easier to manufacture, patterns. The model predicts that using cylindrical channels arranged in a regular hexagonal pattern is ∼6.25 times more efficient for fast charging as compared to grooved lines with both structuring strategies being restricted to a 5% electrode total volume loss. The model also shows that only a very limited electrode volume loss (1%–2%) is required to dramatically improve the wetting (5–20 times) compared to an unstructured electrode.

Tuning the Wettability of a High-Strength Aluminum Alloy Using a Picosecond Laser and Stearic Acid Coating

Imitating microstructures found in nature—such as lotus leaves and Namib beetles—is revolutionary in the field of surface science. Low-energy surfaces, when combined with different topographies, create different wetting states. Understanding the correlation between microstructure geometry and the behavior of water droplets is key to varying the contact angles on a low-energy surface. Here, a picosecond laser was used to modify the microtexture of aluminum alloy surfaces. Various microstructures were formed on the same surface, including the Laser-Induced Periodic Surface Structure (LIPSS), dual micro/nano hierarchical structures, and periodic arrays of a micropattern structure. Coating these microstructures with stearic acid was found to contribute to decreasing surface energy. The 92% fraction of the laser-machined to non-machined surface, when associated with different microgroove depths, created the capacity to form a superhydrophobic surface. Water droplets on a modified surface were transferred from hydrophilic at the Wenzel state to hydrophobic at the Cassie–Baxter state to a superhydrophobic state at microgroove depths ranging between 2.50 μm to 0.3 μm. The air pockets trapped in the microgrooves and nanocavities were found to subsidize the initiation of the composite interface underneath the water droplet.

Abstract 13302: Associations of Allostatic Load With Brain Macro-Morphology, Subclinical Cerebrovascular Disease, and Microstructural Integrity of White Matter Pathways: The Boston Puerto Rican Health Study

Introduction: Allostatic load (AL), a measure of overall body wear and tear, has been associated with structural and functional alterations of the brain, but the evidence remains scarce. We aimed to evaluate the prospective associations of AL with brain MRI measures in the Boston Puerto Rican Health Study (BPRHS). Research Questions: Whether AL is associated with 1) brain macro-morphology: brain age and volumes, 2) subclinical cerebrovascular disease: white matter hyperintensity (WMH) and brain infarcts, and 3) microstructural integrity of white matter (WM) pathways in Puerto Rican adults. Methods: Adults from the BPRHS cohort who provided blood and urine samples at baseline, 2-y, and 6-y visits and underwent MRI scans at 13-y visit were included in analyses (n=226). AL was evaluated as a composite score (0-11) of 11 physiological parameters in five body systems. An overall AL score was calculated by averaging the scores of the baseline, 2-y, and 6-y visits, with higher scores indicating greater dysregulation. We evaluated brain age and volumes using T1-weighted MRI, WMH and brain infarcts using T2-weighted MRI, and microstructural integrity of WM pathways using diffusion tensor imaging. Multivariable logistic regression models were used to examine the associations between AL and brain infarcts, and linear regression models were used for other MRI outcomes. Results: Mean age at baseline was 54.6 ± 6.6 y, with 79.2% female. Higher AL was associated with higher brain age z scores (β = 0.129, P = 0.031) and lower volumes of total WM, cerebral WM (especially parietal and temporal lobes), cerebellum, and brain stem. Higher AL was also associated with higher grades of WMH (β = 0.207, P = 0.024) and higher odds of small vessel infarcts [OR (95% CI) = 3.50 (1.56-7.87), P = 0.002], but not large vessel infarcts [OR (95% CI) = 1.33 (0.73-2.40), P = 0.348]. Diffusion tensor imaging parameters showed that participants with higher AL had more microstructural deterioration patterns in major WM pathways. Conclusions: Higher AL score was associated with brain macro- and microstructural disruptions and a higher risk of subclinical cerebrovascular disease, suggesting that AL may be a potential indicator of the need for early intervention in preventing neuronal damage in older adults.

Generative AI and image based numerical mechanics in wind blade adhesive composites

Numerical modelling of adhesive composites in wind energy is complicated in part due to material heterogeneity. Microstructural CT scan fibre composite patterns or representative elements, which play a major role in defining the mechanical behaviour of these adhesive structures, are both difficult to characterize as well as hard to numerically simulate. With advances in deep learning based generative AI, new ways of predicting the mechanical behaviour of heterogeneous materials is now possible. Here we put forward a data driven method to relate input composite adhesive microstructures with field data using deep learning and generative AI based methods. The prediction of mechanical stress or strain fields or other similar patterns and combining them as a function of boundary conditions, fibre composite microstructure and material models is achieved and the models are trained such that they closely approximate computationally expensive simulations based on numerical FE techniques and would have the ability to generalize. We also create a dataset of wind energy adhesives with their numerical mechanics based FE simulations subject to different boundary conditions and material models for further deep learning based composite studies.

Abrasive machining induced surface layer damage behavior and formation mechanism of monocrystalline β-Ga2O3: A comparative study of nanoindentation and nanogrinding

Beta-phase gallium oxide (β-Ga2O3) has garnered significant attention in recent years as an ultra-wide bandgap semiconductor material. However, its surface layer damage behavior and machining deformation mechanism remain poorly understood. In this work, a systematic comparative study was conducted through nanoindentation and nanogrinding for monocrystalline β-Ga2O3 (−201) crystal plane. Transmission electron microscopy is employed as the primary characterization method. The results show that the microstructural evolution patterns of monocrystalline β-Ga2O3 can be categorized into four stages, i.e. stacking faults, twins, slip bands, and cleavage cracks are observed sequentially. According to the tests results, subsurface damage diagram models based on nanoindentation and nanogrinding are established, both of which exhibit the above evolution patterns as the indentation depth and grit depth of cut increases. However, there are some differences. In the nanogrinding process, nanocrystals and amorphous layers were found near the ground surface, which are related to the high strain rate grinding conditions and the unique material properties of monocrystalline β-Ga2O3 with low stacking fault energy. The results in this work contribute to an enhanced understanding of the deformation characteristics of monocrystalline β-Ga2O3 at macro and micro scales, while offering valuable insights for achieving damage control in ultra-precision machining processes.

Developmental prediction modeling based on diffusion tensor imaging uncovering age-dependent heterogeneity in early childhood autistic brain

ObjectiveThere has been increasing evidence for atypical white matter (WM) microstructure in autistic people, but findings have been divergent. The development of autistic people in early childhood is clouded by the concurrently rapid brain growth, which might lead to the inconsistent findings of atypical WM microstructure in autism. Here, we aimed to reveal the developmental nature of autistic children and delineate atypical WM microstructure throughout early childhood while taking developmental considerations into account.MethodIn this study, diffusion tensor imaging was acquired from two independent cohorts, containing 91 autistic children and 100 typically developing children (TDC), aged 4–7 years. Developmental prediction modeling using support vector regression based on TDC participants was conducted to estimate the WM atypical development index of autistic children. Then, subgroups of autistic children were identified by using the k-means clustering method and were compared to each other on the basis of demographic information, WM atypical development index, and autistic trait by using two-sample t-test. Relationship of the WM atypical development index with age was estimated by using partial correlation. Furthermore, we performed threshold-free cluster enhancement-based two-sample t-test for the group comparison in WM microstructures of each subgroup of autistic children with the rematched subsets of TDC.ResultsWe clustered autistic children into two subgroups according to WM atypical development index. The two subgroups exhibited distinct developmental stages and age-dependent diversity. WM atypical development index was found negatively associated with age. Moreover, an inverse pattern of atypical WM microstructures and different clinical manifestations in the two stages, with subgroup 1 showing overgrowth with low level of autistic traits and subgroup 2 exhibiting delayed maturation with high level of autistic traits, were revealed.ConclusionThis study illustrated age-dependent heterogeneity in early childhood autistic children and delineated developmental stage-specific difference that ranged from an overgrowth pattern to a delayed pattern.Trial registration This study has been registered at ClinicalTrials.gov (Identifier: NCT02807766) on June 21, 2016 (https://clinicaltrials.gov/ct2/show/NCT02807766).

Microstructure, Mechanical and Thermal Properties of ZTA/Al2TiO5 Ceramic Composites

Zirconia-toughened alumina (ZTA)/Al2TiO5 composites were prepared via a sol–gel route. The prepared samples were uniaxially pressed and pressurelessly sintered at 1650–1700 °C for 1 h. The microstructure, densification, and X-ray diffraction patterns of the sintered ZTA/Al2TiO5 composites were investigated, and their mechanical properties, thermal coefficient, and shock resistance were characterized. The addition of Al2TiO5 hindered the grain growth of the alumina particles and enhanced the relative density, Vickers hardness, and bending strength of the composites compared with pure ZTA samples. The fracture toughness was improved by 19% upon the addition of 40 wt% Al2TiO5. Moreover, increasing the Al2TiO5 content resulted in an improvement in the thermal shock resistance.

Microstructure quality assessment for hybrid additive manufactured Ti6Al4V components via ultrasonics

Metal components with functionally organized microstructures for specific applications are emerging thanks to hybrid additive manufacturing (AM). The customization of these high value components accentuates the need for nondestructive methods to characterize their microstructural functional patterns. Nondestructive evaluation (NDE) methods that are economical, fast, energy efficient, and easy to integrate into routine component inspections are preferred. Most importantly, NDE methods must be sensitive to changes in the microstructure such that regions that do not satisfy the design requirements (i.e. out-of-spec regions) can be detected. In this work, ultrasonic NDE methods grounded in diffuse backscatter modeling were used to detect and quantify spatial property variations resulting from a hybrid AM process. The manufacturing process coupled directed energy deposition (DED) with milling in a cyclical manner. These methods were successfully implemented to evaluate the microstructural uniformity of Ti6Al4V samples as well as to make comparisons across an ensemble of samples manufactured with identical parameters. Out-of-spec regions were mapped with respect to the sample geometry on a layer-by-layer basis. The results of this work are expected to inform future NDE strategies for both research and practitioner contexts, and limitations are discussed.

Direct printing of graphene terahertz closed-ring resonator array from periodic single droplets via enhanced coffee-ring effect

Graphene terahertz (THz) devices have emerged as a pivotal player in the THz area, and drop-on-demand (DOD) printing technology enables cost-effective patterning of THz microstructures. However, fast printing of THz microstructures and devices suffers from low efficiency owing to the drop-by-drop overlapping process. Here, we have developed a facile direct printing method to fabricate graphene THz closed-ring resonator (CRR) arrays from periodic single droplets ascribing to the enhanced coffee-ring effect. The construction of a complete graphene micro-ring was achieved using small reduced graphene oxide sheets, enabling the strategy of a graphene CRR from one single droplet. We attributed the mechanism of strengthened coffee-ring effect to the swift pinning, gapless between the contact line and the solute line, and close packing. Finally, we prepared a graphene THz CRR array featuring fine rings with widths of ∼12.3 μm, a high THz extinction ratio of 66.9%, and the highest measurement λ (relative THz response) of 9.8 documented so far for graphene-based THz microstructures and devices. Such an array from the expeditious DOD printing process exhibits a pronounced THz response and possible fast switching speed, which suggests new possibilities in building graphene THz microstructures, benefiting the future development of graphene THz devices.

Biochemical, Microstructural, and Probiotic Bacterial Patterns of Innovative Fresh Cheese Fortified with Helianthus tuberosus Tubers

Recently, functional foods have become the aim of customers and food producers. Integrating vegetable ingredients in the food industry is a productive goal to reduce costs while maintaining quality. Dried Jerusalem artichoke tubers powder (DJATP) was used as a novel approach in cheese manufacturing. Innovatively, its holding capacity features and impact on probiotic development were evaluated. The SEM microstructure image and biochemical analysis of DJATP confirmed higher water holding (5.31 g/g), oil absorption (1.99 g/g), and swelling (1.79 g/g) capacities than casein. DJATP (3%) supported the probiotic bacterial growth (Streptococcus thermophilus, Bifidobacterium bifidum, and Lactobacillus acidophilus) and accelerated the fermentation of skimmed milk more than pure inulin. When fortified with DJATP (3% or 6%), the cheese yield increased (24.66% and 27.85%, respectively) compared with 17.55% for control after storage (14 days). Besides the high levels of amino acids, minerals, flavonoids, phenols, and antioxidants, the probiotic bacteria in the DJATP-fortified cheese were better active, with better sensory features, recording the highest judging score (87.67) against the control (79.00). To our knowledge, no preceding studies used DJATP in fresh cheese manufacturing followed the probiotic behavior in DJATP or compared the microstructure of DJATP and casein. Instead of inulin, our novel approach suggests using DJATP as a prebiotic and an enhancer for fresh cheese quality and yield, all while being cost-effective. Future studies are encouraged to explore the potential use of DJATP in other functional cheese products.

Optimization of Microstructure Patterning for Flexible Bioelectronics Application

Recent advancements in flexible electronics and wearable sensors have given biomedical technology a new edge overcoming the limitations of traditional rigid silicon-based electronics. Furthermore, high flexibility of these wearable sensors enables it to conformally sit over any uneven surface helping in accurate determination of any physical, chemical, or physiological parameter associate with the surface. Conventionally expensive micro/nano photolithography techniques under strict clean room conditions are used for the development of these flexible and wearable biomedical sensors with high degree of accuracy and sensitivity. However, the developed wearable sensors need not only be extremely sensitive, but also cost effective for its successful usage. To address this, the present work discusses the use of a photo-patternable UV sheet for realization of micro patterns over flexible copper cladded surface eliminating the need of costly clean room facilities. It demonstrates the standardization of various design geometries using the photo-patternable UV sheet over the flexible surface similar to photolithography process and involves optimization of the exposure timing of the UV sheets and their development time towards various design patterns over different thick film metal surfaces. Finally, patterned micro devices like micro-electrodes were successfully realized using the above process to ascertain its efficacy.

Novel Fabrication of 3-D Cell Laden Micro-Patterned Porous Structure on Cell Growth and Proliferation by Layered Manufacturing.

This study focuses on developing and characterizing a novel 3-dimensional cell-laden micro-patterned porous structure from a mechanical engineering perspective. Tissue engineering holds great promise for repairing damaged organs but faces challenges related to cell viability, biocompatibility, and mechanical strength. This research aims to overcome these limitations by utilizing gelatin methacrylate hydrogel as a scaffold material and employing a photolithography technique for precise patterned fabrication. The mechanical properties of the structure are of particular interest in this study. We evaluate its ability to withstand external forces through compression tests, which provide insights into its strength and stability. Additionally, structural integrity is assessed over time to determine its performance in in vitro and potential in vivo environments. We investigate cell viability and proliferation within the micro-patterned porous structure to evaluate the biological aspects. MTT assays and immunofluorescence staining are employed to analyze the metabolic activity and distribution pattern of cells, respectively. These assessments help us understand the effectiveness of the structure in supporting cell growth and tissue regeneration. The findings of this research contribute to the field of tissue engineering and provide valuable insights for mechanical engineers working on developing scaffolds and structures for regenerative medicine. By addressing challenges related to cell viability, biocompatibility, and mechanical strength, we move closer to realizing clinically viable tissue engineering solutions. The novel micro-patterned porous structure holds promise for applications in artificial organ development and lays the foundation for future advancements in large soft tissue construction.

Microemulsions supported by octyl monoglucoside and geraniol. 3. Microstructure & general pattern

This paper completes previous studies on the phase behaviour and microstructure of the quaternary microemulsion water – cyclohexane – n-octyl-β-D-glucoside (β-C8G1) – geraniol. The properties of this system are almost insensitive to temperature, while they can be tuned easily by adding an alcohol as co-surfactant. The addition of the alcohol changes the composition of the interfacial film, which, in turn, is the tuning parameter for the quaternary system. Studies of the phase behaviour together with SANS and NMR measurements allow drawing a quantitative picture of how the domain size ξ, the curvature H, and the interfacial tension σab depend on the composition of the interfacial film. The SANS data of both oil-in-water and water-in-oil droplet microemulsions recorded near the emulsification failure boundary were evaluated with the Generalised Indirect Fourier Transformation (GIFT), revealing a growth towards cylindrical structures when approaching the respective critical end point. We will show that the general behaviour of ternary and quaternary systems is equal if the appropriate tuning parameters are chosen. In addition, we will show that it is possible to apply the scaling description derived for temperature-dependent ternary systems to composition-dependent quaternary systems: plotting the reduced domain size, the reduced curvature and the reduced interfacial tension against the proper reduced tuning parameter, i.e., either the reduced temperature or the reduced interfacial composition, leads to one master curve for all systems.