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Partial Sum Quantization for Reducing ADC Size in ReRAM-based Neural Network Accelerators
No full textWhile ReRAM (Resistive Random-Access Memory) crossbar arrays have the potential to significantly accelerate DNN (Deep Neural Network) training through fast and lowcost matrix-vector multiplication, peripheral circuits like ADCs (analog-to-digital converters) create a high overhead. These ADCs consume over half of the chip power and a considerable portion of the chip cost. To address this challenge, we propose advanced quantization techniques that can significantly reduce the ADC overhead of ReRAM crossbar arrays. Our methodology interprets ADC as a quantization mechanism, allowing us to scale the range of ADC input optimally along with the weight parameters of a DNN, resulting in multiple-bit reduction in ADC precision. This approach reduces ADC size and power consumption by several times, and it is applicable to any DNN type (binarized or multi-bit) and any ReRAM crossbar array size. Additionally, we propose ways to minimize the overhead of the digital scaler, which is an essential part of our scheme and sometimes required. Our experimental results using ResNet-18 on the ImageNet dataset demonstrate that our method can reduce the size of the ADC by 32 times compared to ISAAC with only a minimal accuracy loss degradation of 0.24 evaluation results in the presence of ReRAM non-ideality (such as stuck-at fault). IEE
Decellularized human pancreatic extracellular matrix-based physiomimetic microenvironment for human islet culture
No full textA strategy that seeks to combine the biophysical properties of inert encapsulation materials like alginate with the biochemical niche provided by pancreatic extracellular matrix (ECM)-derived biomaterials, could provide a physiomimetic pancreatic microenvironment for maintaining long-term islet viability and func-tion in culture. Herein, we have demonstrated that incorporating human pancreatic decellularized ECM within alginate microcapsules results in a significant increase in Glucose Stimulation Index (GSI) and to-tal insulin secreted by encapsulated human islets, compared to free islets and islets encapsulated in only alginate. ECM supplementation also resulted in long-term (58 days) maintenance of GSI levels, similar to that observed in free islets at the first time point (day 5). At early time points in culture, ECM promoted gene expression changes through ECM-and cell adhesion-mediated pathways, while it demonstrated a mitochondria-protective effect in the long-term.Statement of significanceThe islet isolation process can damage the islet extracellular matrix, resulting in loss of viability and func-tion. We have recently developed a detergent-free, DI-water based method for decellularization of human pancreas to produce a potent solubilized ECM. This ECM was added to alginate for microencapsulation of human islets, which resulted in significantly higher stimulation index and total insulin production, com-pared to only alginate capsules and free islets, over long-term culture. Using ECM to preserve islet health and function can improve transplantation outcomes, as well as provide novel materials and platforms for studying islet biology in microfluidic, organ-on-a-chip, bioreactor and 3D bioprinted systems.(c) 2023 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved
Synthesis of size-controllable, yolk-shell metal sulfide spheres for hybrid supercapacitors
No full textDeveloping complex nanostructured materials with amorphous phases remains an important challenge and such materials are potentially valuable for achieving highly efficient electrochemical energy storage. Here, a facile surfactant-free strategy is developed to synthesize size-controllable Ni-Co-Mn sulfide spheres with an amorphous and yolk-shell structure. In the absence of surfactant, monodispersed Ni-Co-Mn glycerate solid spheres with diameters ranging from 650 to 1100 nm are controllably synthesized by regulating the amount of Mn(NO3)2, and subsequently transformed into yolk-shelled amorphous Ni-Co-Mn sulfide spheres via an anion-exchange reaction. Benefitting from compositional and structural advantages, the optimized electrode displays an outstanding specific capacity of 1204 C g-1 at 2 A g-1 with a long cycling lifetime. A hybrid supercapacitor, fabricated with the yolk-shelled amorphous Ni-Co-Mn sulfide spheres as the positive electrode material and activated carbon as the negative one, achieves superior cyclic stability with a high energy density of 71.86 Wh kg- 1 at 793.56 W kg -1, demonstrating their potential application for high-performance hybrid supercapacitors
From Challenges to Success: A road map for early career researchers [Young Professionals]
No full textYoung professionals, including graduate students and early career researchers, find themselves contemplating their future career paths, which may involve working in industrial research labs or government-funded institutes or pursuing an academic career. However, it is not uncommon for some individuals to hold the misconception that certain paths are obstructed by insurmountable barriers or a metaphorical 'glass ceiling.&apos
Size-Objective Micromechanics Model Trained With Datasets Based on a Fiber Pair and Surrounding Fibers
No full textTargeting the Mitochondrial Chaperone TRAP1 Alleviates Vascular Pathologies in Ischemic Retinopathy
No full textActivation of hypoxia-inducible factor 1?? (HIF1??) contributes to blood-retinal barrier (BRB) breakdown and pathological neovascularization responsible for vision loss in ischemic retinal diseases. During disease progression, mitochondrial biology is altered to adapt to the ischemic environment created by initial vascular dysfunction, but the mitochondrial adaptive mechanisms, which ultimately contribute to the pathogenesis of ischemic retinopathy, remain incompletely understood. In the present study, it is identified that expression of mitochondrial chaperone tumor necrosis factor receptor-associated protein 1 (TRAP1) is essential for BRB breakdown and pathologic retinal neovascularization in mouse models mimicking ischemic retinopathies. Genetic Trap1 ablation or treatment with small molecule TRAP1 inhibitors, such as mitoquinone (MitoQ) and SB-U015, alleviate retinal pathologies via proteolytic HIF1?? degradation, which is mediated by opening of the mitochondrial permeability transition pore and activation of calcium-dependent protease calpain-1. These findings suggest that TRAP1 can be a promising target for the development of new treatments against ischemic retinopathy, such as retinopathy of prematurity and proliferative diabetic retinopathy
Rheological investigation of neonatal double-lumen cannula with and without deformable erythrocytes
No full textThe double-lumen cannula (DLC) is the most critical component of extracorporeal membrane oxygenation (ECMO) because of its narrow cross-section, thereby developing the highest shear stress in the entire ECMO circuit. To measure blood damage in a DLC, the Eulerian approach is generally used without contemplating exposure time or history of blood exposure to shear stresses. Alternatively, Lagrangian approach has also been recently employed for a Newtonian blood flow through a DLC, thereby leaving a research gap on the impact of variable shear rate in case of non-Newtonian blood flow. In the present study, the hemodynamic performance of DLC is investigated using different non-Newtonian models by applying Lagrangian approach. Moreover, the motion of RBC was tracked inside the cannula to predict its behavior during the motion. The results showed that the return lumen had higher pressure, velocity, and shear stress values than other parts of the DLC. In addition, recirculation was observed due to the mixing of blood coming from different inlets and found increase with increasing flow rate of blood. Moreover, it was found that the blood damage increased with increasing flow rate. There was more blood damage in the Newtonian model than in the other non-Newtonian models at higher flow rates. However, the Carreau model showed more blood damage at lower flow rates than the other models. The Cross model showed DLC's higher efficacy in delivering oxygenated blood to the tricuspid outlet because it showed the least blood damage among all other models. It was also concluded that the efficacy of the DLC to deliver oxygenated blood to the tricuspid outlet decreases with increasing blood flow rate
Age-associated spinal stenosis in the turquoise killifish
No full textAging triggers spinal degeneration, including common spinal stenosis, which causes back and leg pain in older individuals, significantly impacting their quality of life. Here, we explored aging traits in turquoise killifish spines, potentially offering a model for age-linked spinal stenosis in humans. Aged turquoise killifish exhibited body shape deformation and increased vertebral collapse, which was further accelerated by spawning. High-resolution CT scans revealed suppressed cortical bone thickness and hemal arch area in vertebrae due to spawning, and osteophyte formation was observed in both aged and breeding fish populations. Scale mineralization mirrored these changes, increasing with age but being suppressed by spawning. The expression of sp7, sox9b, axin1, and wnt4a/b genes can be utilized to monitor age-and reproduction-dependent spine deformation. This study demonstrates that turquoise killifish and humans share certain phenotypes of age-related vertebral abnormalities, suggesting that turquoise killifish could serve as a potential model for studying human spinal stenosis
