Co-Adjusting Voltage/Frequency State and Interrupt Rate for Improving Energy-Efficiency of Latency-Critical Applications

As the power/energy consumption is one of the major contributors to the Total Cost of Ownership (TCO), improving power/energy efficiency is crucial for large-scale data centers where latency-critical applications are commonly accommodated while computing resources are usually under-utilized. For improving the power/energy efficiency of processors, most of the commercial processors support Dynamic Voltage and Frequency Scaling (DVFS) technology that enables to adjust Voltage and Frequency state (V/F state) of the processor dynamically. In particular, for the latency-critical applications, many prior studies propose power management policies using the DVFS for the latency-critical applications, which minimizes the performance degradation or satisfies the Service Level Objectives (SLOs) constraints. Meanwhile, although the interrupt rate also affects the response latency and energy efficiency of latency-critical applications considerably, those prior studies just introduce policies for V/F state adjustment while not considering the interrupt rate. Therefore, in this article, we investigate the impact of adjusting the interrupt rate on the tail response latency and energy consumption. Through our experimental results, we observe that adjusting interrupt rate along with V/F state management varies the performance and energy consumption considerably, and provides an opportunity to reduce energy further by showing latency overlap between different V/F states. Based on the observation, we show the quantitative potential in improving energy efficiency of co-adjusting V/F state and interrupt rate with a simple management policy, called Co-PI. Co-PI searches the most energy-efficient combination of the V/F state and interrupt rate from the latency and energy tables that we obtain through offline profiling, and reflect the combination to the core and NIC. Co-PI reduces energy consumption by 34.1% and 25.1% compared with performance and ondemand governors while showing the almost same tail response latency with the performance governor that operates cores at the highest V/F state statically. © 1991 BMJ Publishing Group. All rights reserved.1

Condensed ECM-based nanofilms on highly permeable PET membranes for robust cell-to-cell communications with improved optical clarity

The properties of a semipermeable porous membrane, including pore size, pore density, and thickness, play a crucial role in creating a tissue interface in a microphysiological system (MPS) because it dictates multicellular interactions between different compartments. The small pore-sized membrane has been preferentially used in an MPS for stable cell adhesion and the formation of tissue barriers on the membrane. However, it limited the applicability of the MPS because of the hindered cell transmigration via sparse through-holes and the optical translucence caused by light scattering through pores. Thus, there remain unmet challenges to construct a compartmentalized MPS without those drawbacks. Here we report a submicrometer-thickness (similar to 500 nm) fibrous extracellular matrix (ECM) film selectively condensed on a large pore-sized track-etched (TE) membrane (10 mu m-pores) in an MPS device, which enables the generation of functional tissue barriers simultaneously achieving optical transparency, intercellular interactions, and transmigration of cells across the membrane. The condensed ECM fibers uniformly covering the surface and 10 mu m-pores of the TE membrane permitted sufficient surface areas where a monolayer of the human induced pluripotent stem cell-derived brain endothelial cells is formed in the MPS device. The functional maturation of the blood-brain barrier (BBB) was proficiently achieved due to astrocytic endfeet sheathing the brain endothelial cells through 10 mu m pores of the condensed-ECM-coated TE (cECMTE) membrane. We also demonstrated the extravasation of human metastatic breast tumor cells through the human BBB on the cECMTE membrane. Thus, the cECMTE membrane integrated with an MPS can be used as a versatile platform for studying various intercellular communications and migration, mimicking the physiological barriers of an organ compartment

Metabolites of Purine Nucleoside Phosphorylase (NP) in Serum Have the Potential to Delineate Pancreatic Adenocarcinoma

Pancreatic Adenocarcinoma (PDAC), the fourth highest cause of cancer related deaths in the United States, has the most aggressive presentation resulting in a very short median survival time for the affected patients. Early detection of PDAC is confounded by lack of specific markers that has motivated the use of high throughput molecular approaches to delineate potential biomarkers. To pursue identification of a distinct marker, this study profiled the secretory proteome in 16 PDAC, 2 carcinoma in situ (CIS) and 7 benign patients using label-free mass spectrometry coupled to 1D-SDS-PAGE and Strong Cation-Exchange Chromatography (SCX). A total of 431 proteins were detected of which 56 were found to be significantly elevated in PDAC. Included in this differential set were Parkinson disease autosomal recessive, early onset 7 (PARK 7) and Alpha Synuclein (aSyn), both of which are known to be pathognomonic to Parkinson's disease as well as metabolic enzymes like Purine Nucleoside Phosphorylase (NP) which has been exploited as therapeutic target in cancers. Tissue Microarray analysis confirmed higher expression of aSyn and NP in ductal epithelia of pancreatic tumors compared to benign ducts. Furthermore, extent of both aSyn and NP staining positively correlated with tumor stage and perineural invasion while their intensity of staining correlated with the existence of metastatic lesions in the PDAC tissues. From the biomarker perspective, NP protein levels were higher in PDAC sera and furthermore serum levels of its downstream metabolites guanosine and adenosine were able to distinguish PDAC from benign in an unsupervised hierarchical classification model. Overall, this study for the first time describes elevated levels of aSyn in PDAC as well as highlights the potential of evaluating NP protein expression and levels of its downstream metabolites to develop a multiplex panel for non-invasive detection of PDAC

GreenDIMM: OS-Assisted DRAM Power Management for DRAM with a Sub-Array Granularity Power-Down State

Power and energy consumed byDRAMcomprising main memory of data-center servers have increased substantially as the capacity and bandwidth of memory increase. Especially, the fraction of DRAM background power in DRAM total power is already high, and it will continue to increase with the decelerating DRAM technology scaling as we will have to plug more DRAM modules in servers or stack more DRAM dies in a DRAM package to provide necessary DRAM capacity in the future. To reduce the background power, we may exploit low average utilization of the DRAM capacity in data-center servers (i.e., 40 C60%) for DRAM power management. Nonetheless, the current DRAM power management supports lowpower states only at the rank granularity, which becomes ineffective with memory interleaving techniques devised to disperse memory requests across ranks. That is, ranks need to be frequently woken up from low-power states with aggressive power management, which can significantly degrade system performance, or they do not get a chance to enter low-power states with conservative power management. To tackle such limitations of the current DRAM power management, we propose GreenDIMM, OS-assisted DRAM power management. Specifically, GreenDIMM first takes a memory block in physical address space mapped to a group of DRAM sub-arrays across every channel, rank, and bank as a unit of DRAM power management. This facilitates fine-grained DRAM power management while keeping the benefit of memory interleaving techniques. Second, GreenDIMM exploits memory on-/off-lining operations of the modern OS to dynamically remove/add memory blocks from/to the physical address space, depending on the utilization of memory capacity at run-time. Third, GreenDIMM implements a deep powerdown state at the sub-array granularity to reduce the background power of the off-lined memory blocks. As the off-lined memory blocks are removed from the physical address space, the sub-arrays will not receive any memory request and stay in the power-down state until the memory blocks are explicitly on-lined by the OS. Our evaluation with a commercial server running diverse workloads shows that GreenDIMM can reduce DRAM and system power by 36% and 20%, respectively, with ~1% performance degradation. © 2021 Association for Computing Machinery

Effect of iridium oxide as an additive on catalysts with different Pt contents in cell reversal conditions of polymer electrolyte membrane fuel cells

© 2021 Hydrogen Energy Publications LLCCell reversal is observed when a current load is applied to the polymer electrolyte membrane fuel cell under fuel starvation conditions. Cell reversal causes severe corrosion (or oxidation) of the carbon support in the anode, which leads to a decrease in overall fuel cell performance. To suppress the corrosion reaction of carbon under cell reversal conditions and to increase the durability of fuel cells, studies on anode additives are being conducted. However, studies on the effect of additives on catalysts with different platinum contents have not been conducted. In this study, 20 wt%, 40 wt%, 60 wt% commercial Pt/C catalyst was applied to the anode, and 50 cycles of cell reversal were performed. Furthermore, the performance change with and without IrO2 as an additive was observed and its effect was assessed. Changes in the morphologies of the electrodes before and after cell reversal tests were also observed using a transmission electron microscope and a scanning electron microscope. The higher the platinum content of the catalyst, the more resistant to cell reversal. In addition, the addition of IrO2 to the anode effectively prevents performance degradation due to cell reversal.11Nsciescopu

Development of an Autonomous Underwater Vehicle ISiMI6000 for Deep-sea Observation

1034-1041The Korea Institute of Ocean Science and Technology (KIOST) has developed AUVs for survey on the swallow sea, and is under developing a deep-sea AUV based on the former experience. Since 2010, the AUV named ISiMI6000 was designed to explore the deep-seabed topography and hydrothermal vent up to 6,000 m depth. ISiMI6000 was designed witha cylindrical shape having Myringform to minimize fluid resistance. It has one main thruster and four control planes, of which the maximum speed is 4 knots and has over 1.5 knots in up/down direction. It equips with an underwater navigation system composed of Ultra Short Baseline (USBL), Doppler Velocity Log (DVL), Attitude and Heading Reference System (AHRS), Inertial Measurement Unit (IMU), Obstacle Avoid System (OAS), and Global Positioning System (GPS). Its communication tools are Acoustic Telemetry Modem (ATM) under the sea and Radio Frequency (RF) modem at surface. Oceanographic sensors were equipped for precise survey on the deep-sea floor, such as Conductivity Temperature Depth (CTD), Side Scan Sonar (SSS), methane sensor, and sub-bottom profiler (SBP) in optional. A HD Camera and LED light was installed for monitoring the sea floor, and an emergency managing device was designed with a weight drop system, a radio beacon and a xenon flash. This paper introduces the system design and configuration of ISiMI6000 and describes the operating software system in brief. This paper also describes a tank tests and field tests to evaluate the operation process and navigation performance at the Southern Sea

Enhanced delivery to brain using sonosensitive liposome and microbubble with focused ultrasound

© 2022 Elsevier B.V.Glioblastoma is considered one of the most aggressive and dangerous brain tumors. However, treatment of GBM has been still challenged due to blood-brain barrier (BBB). BBB prevents that the chemotherapeutic molecules are extravasated to brain. In this study, sonosensitive liposome encapsulating doxorubicin (DOX) was developed for enhancement of GBM penetration in combination with focused ultrasound (FUS) and microbubbles. Upon ultrasound (US) irradiation, microbubbles induce cavitation resulting in the tight junction of BBB endothelium to temporarily open. In addition, the composition of sonosensitive liposome was optimized by comparison of sonosensitivity and intracellular uptake to U87MG cells. The optimal sonosensitive liposome, IMP301-DC, resulted 123.9 ± 38.2 nm in size distribution and 98.2 % in loading efficiency. Related to sonosensitivity of IMP301-DC, US-triggered release ratio of doxorubicin was 69.2 ± 12.3 % at 92 W/cm2 of US intensity for 1 min. In the in vivo experiments, the accumulation of DiD fluorescence probe labeled IMP301-DC-shell in the brain through the BBB opening was increased more than two-fold compared to that of Doxil-shell, non-sonosensitive liposome. US exposure significantly increased GBM cytotoxicity of IMP301-DC. In conclusion, this study demonstrated that IMP301-DC could serve as an alternative solution to enhance the penetration to GBM treatment via BBB opening by non-invasive FUS combined with microbubbles.N