MARACAS: a real-time multicore VCPU scheduling framework

This paper describes a multicore scheduling and load-balancing framework called MARACAS, to address shared cache and memory bus contention. It builds upon prior work centered around the concept of virtual CPU (VCPU) scheduling. Threads are associated with VCPUs that have periodically replenished time budgets. VCPUs are guaranteed to receive their periodic budgets even if they are migrated between cores. A load balancing algorithm ensures VCPUs are mapped to cores to fairly distribute surplus CPU cycles, after ensuring VCPU timing guarantees. MARACAS uses surplus cycles to throttle the execution of threads running on specific cores when memory contention exceeds a certain threshold. This enables threads on other cores to make better progress without interference from co-runners. Our scheduling framework features a novel memory-aware scheduling approach that uses performance counters to derive an average memory request latency. We show that latency-based memory throttling is more effective than rate-based memory access control in reducing bus contention. MARACAS also supports cache-aware scheduling and migration using page recoloring to improve performance isolation amongst VCPUs. Experiments show how MARACAS reduces multicore resource contention, leading to improved task progress.http://www.cs.bu.edu/fac/richwest/papers/rtss_2016.pdfAccepted manuscrip

Analysis and development of phase retrieval algorithms for ptychography

Ptychography, a relatively new form of phase retrieval, can reconstruct both intensity and phase images of a sample from a group of diffraction patterns, which are recorded as the sample is translated through a grid of positions. To recover the phase information lost in the recording of these diffraction patterns, iterative algorithms must optimise an objective function full of local minima, in a huge multidimensional space. Many such algorithms have been developed, each aiming to converge rapidly whilst avoiding stagnation. This thesis aims to set a standard error metric for comparing some of the more popular algorithms, to determine their advantages and disadvantages under a range of different conditions, and hence develop a more adaptive algorithm that combines the advantages of these ancestors. In this thesis, different algorithms are explained together with their reconstruction results from both simulated and practical data. Modifications for mPIE, ADMM and RAAR are suggested to either reducing the number of parameters or improving their computation efficiency. An improved spatial error metric, which can evaluate the reconstruction quality by removing inherent ambiguities, is introduced to compare these algorithms. Based on the explained phase retrieval algorithms, a new algorithm, i.e., adaptive PIE, is developed. It has。 a faster converging speed and better accuracy comparing to its ancestors

Effects of Electrolyte Cations on Electrochemical CO2 Reduction via Analysis of the Electrode-Electrolyte Interface

Urgent actions are required to protect the environment from catastrophic climate change; to accomplish this we need to decrease our dependence on fossil fuels and reduce the CO2 concentration in the atmosphere. The electrocatalytic CO2 reduction reaction (CO2RR) is a promising solution for converting CO2 to energy-dense chemical fuels from intermittent renewable energy. Copper-based materials are widely explored for electrochemical CO2RR since it is the only metal that is capable of catalyzing CO2 reduction to a wide range of hydrocarbons. However, it is still challenging to achieve an appreciable conversion rate and selectivity for large-scale CO2 conversion in industrial applications. The hydrogen evolution reaction (HER) is a competitive side reaction that reduces the performance of CO2 conversion. The HER occurs during CO2RR because it has a lower onset potential and lower kinetic barrier than the potentials required to reduce CO2. Therefore, this thesis aims to understand how cations in electrolyte affect the performance of CO2RR and HER on copper electrodes via analysis of the electrode-electrolyte interface. Surface-enhanced infrared absorption spectroscopy (SEIRAS) can be used to track surface-adsorbed species on the electrode and sketch a profile of electrical double layer (EDL) under reaction conditions. The replacement of a significant fraction of interfacial water and the perturbation of surface-adsorbed CO are caused by the presence of cationic CTAB, an amphiphilic ionic organic molecule, which leads to the enhanced performance of CO2RR and HER suppression. The interplay between various alkali cations and CTAB was investigated during electrochemical CO2RR on copper electrodes. Alkali cations coexist with CTAB within the double layer which gives rise to an improved formate generation. This work demonstrates a significant correlation between interfacial cations and the performance of electrochemical CO2 conversion, which also provides fundamental insights for understanding reaction pathways. Findings in this work are valuable for designing efficient routes for CO2RR and other electrocatalytic reactions

Multi-layer reconstruction of skull base after endoscopic transnasal surgery for invasive pituitary adenomas

Objective. To explore the efficacy of multi-layer skull base reconstruction after endoscopic transnasal surgery for invasive pituitary adenomas (IPAs). Clinical rationale for the study. Skull base reconstruction for IPAs. Material and methods. This retrospective analysis involved 160 patients with IPAs who underwent operations from October 2018 to October 2020. All patients were diagnosed with IPAs by pituitary enhanced magnetic resonance imaging, and all tumours were confirmed to be Knosp grades 3a, 3b, or 4. The experimental group and the control group comprised 80 patients in each, and we used different methods to reconstruct the skull base in each group. The comparison indicators included cerebrospinal fluid leakage, sellar floor bone flap (or middle turbinate) shifting, delayed healing of the skull base reconstructed tissue, nasal discomfort, and epistaxis. We used the chi-square test, and p < 0.05 was considered statistically significant. Results. In the experimental group, cerebrospinal fluid leakage occurred intraoperatively in 73 patients, two of whom had cerebrospinal fluid leakage postoperatively. Brain CT 12 months postoperatively showed no sellar floor bone flap (or middle turbinate) shifting. Endoscopic transnasal checks performed seven days after surgery showed that the skull base reconstructed tissue had healed in 74 patients and had failed to heal in six. However, endoscopic transnasal checks showed that all six of these patients’ pedicled nasoseptal flaps had healed well by 14 days after surgery. Other sequelae comprised nasal discomfort in four patients, and epistaxis in four. In the control group, cerebrospinal fluid leakage occurred intraoperatively in 71 patients, 14 of whom had cerebrospinal fluid leakage postoperatively. Brain CT 12 months postoperatively showed floor bone flap (or middle turbinate) shifting in 12 patients. Endoscopic transnasal checks performed seven days after surgery showed that the skull base reconstructed tissue had healed in 65 patients. In 12 patients, pedicled nasoseptal flaps had healed well by 14 days after surgery, while the remaining three patients required reoperation. Other sequelae comprised nasal discomfort in five patients, and epistaxis in six. Conclusions. This new method of multi-layer skull base reconstruction could play an important role in endoscopic transnasal IPA surgery

Association of GSTM1 Null Allele with Prostate Cancer Risk: Evidence from 36 Case-Control Studies

WOS:000312385200061Peer reviewe

Chk1 Inhibition Ameliorates Alzheimer's Disease Pathogenesis and Cognitive Dysfunction Through CIP2A/PP2A Signaling

Alzheimer's disease (AD) is the most common neurodegenerative disease with limited therapeutic strategies. Cell cycle checkpoint protein kinase 1 (Chk1) is a Ser/Thr protein kinase which is activated in response to DNA damage, the latter which is an early event in AD. However, whether DNA damage-induced Chk1 activation participates in the development of AD and Chk1 inhibition ameliorates AD-like pathogenesis remain unclarified. Here, we demonstrate that Chk1 activity and the levels of protein phosphatase 2A (PP2A) inhibitory protein CIP2A are elevated in AD human brains, APP/PS1 transgenic mice, and primary neurons with A beta treatment. Chk1 overexpression induces CIP2A upregulation, PP2A inhibition, tau and APP hyperphosphorylation, synaptic impairments, and cognitive memory deficit in mice. Moreover, Chk1 inhibitor (GDC0575) effectively increases PP2A activity, decreases tau phosphorylation, and inhibits A beta overproduction in AD cell models. GDC0575 also reverses AD-like cognitive deficits and prevents neuron loss and synaptic impairments in APP/PS1 mice. In conclusion, our study uncovers a mechanism by which DNA damage-induced Chk1 activation promotes CIP2A-mediated tau and APP hyperphosphorylation and cognitive dysfunction in Alzheimer's disease and highlights the therapeutic potential of Chk1 inhibitors in AD

DESIGN AND INITIAL EVALUATION OF AN AUTONOMOUS ROBOTIC SYSTEM FOR ULTRASOUND-GUIDED VASCULAR ACCESS

Trauma is the leading cause of death for individuals aged 45 years or less in the United States and uncontrolled abdominal hemorrhage is responsible for 30 to 40% of trauma mortality. These hemorrhage trauma sometimes happens far away from the trauma center and some of them occur on the battlefield. It is critical to improve temporize the hemorrhage in time before the patient receives definitive care. Although plenty of hemorrhage control techniques have been developed in recent decades, none of the techniques was perfect and often come with complications and risks. REBOA is one example of a hemorrhage control technique that has been invented for several decades but the hospitals and trauma centers remain very conservative about this technique because of its complications and risks. Incorrect performance of the procedure could lead to unexpected complications and put the patients in danger. This thesis proposes an autonomous robotic system that locates the femoral artery of the patient and inserts the needle into the target location. This vascular access robot would make up for the disadvantages of REBOA. The robot is designed and assembled. Some experiments were performed to conclude an initial evaluation of the robot system. Most of the components of the robot were able to meet the expectations. However, a more thorough evaluation of the accuracy and repeatability of the robot needs to be conducted. Some design modifications need to be made to the robot design before it can perform the vascular access procedure of REBOA

A Hybrid Model Based on Principal Component Analysis, Wavelet Transform, and Extreme Learning Machine Optimized by Bat Algorithm for Daily Solar Radiation Forecasting

Precise solar radiation forecasting is of great importance for solar energy utilization and its integration into the grid, but because of the daily solar radiation’s intrinsic non-stationary and nonlinearity, which is influenced by a lot of elements, single predicting models may have difficulty obtaining results with high accuracy. Therefore, this paper innovatively puts forward an original hybrid model that predicts solar radiation through extreme learning machine (ELM) optimized by the bat algorithm (BA) based on wavelet transform (WT) and principal component analysis (PCA). First, choose the meteorological variables on the basis of Pearson coefficient test, and WT will decompose historical solar radiation into two time series, which are de-noised signal and noise signal. In the approximate series, the lag phase of historical radiation is obtained by partial autocorrelation function (PACF). After that, use PCA to reduce the dimensions of the influencing factors, including meteorological variables and historical radiation. Finally, ELM is established to predict daily solar radiation, whose input weight and deviation thresholds gained optimization by BA, thus it is called BA-ELM henceforth. In view of the four distinct solar radiation series obtained by NASA, the empirical simulation explained the hybrid model’s validity and effectiveness compared to other primary methods