Migration, assignment, and scheduling of jobs in virtualized environment

Abstract Migration is an interesting issue for managing resource utilization and performance in clusters. Recent advances in server virtualization have made migration a practical method to achieve these goals. Especially, the live migration of virtualized servers made their pausing times negligible. However, migration of a virtual machine (VM) can slow down other collocated VMs in multiresource shared systems, where all the system resources are shared among collocated VMs. In parallel execution environment, such sudden slow-down phase of systems is called system noise; it may slow down overall systems while increasing the variability of system performance. When we consider the virtual machine assignment problem as resource allocation, those performance issues are hard to be properly treated. In this work, we address how to consider performance in assigning VMs. To achieve this goal, we model a migration process of a VM instance as a pair of jobs that run at the hosts of sender and receiver. We propose a method to analyze the migration time and the performance impact on multiresource shared systems for completing given VM assignment plan. This study may contribute to create more robust performance in virtualized environment

Histidine 454 plays an important role in polymerization of human glutamate dehydrogenase

AbstractAlthough previous chemical modification studies have suggested several residues to be involved in the maintenance of the quaternary structure of glutamate dehydrogenase (GDH), there are conflicting views for the polymerization process and no clear evidence has been reported yet. In the present study, cassette mutagenesis at seven putative positions (Lys333, Lys337, Lys344, Lys346, Ser445, Gly446, and His454) was performed using a synthetic human GDH gene to examine the polymerization process. Of the mutations at the seven different sites, only the mutagenesis at His454 results in depolymerization of the hexameric GDH into active trimers as determined by HPLC gel filtration analysis and native gradient polyacrylamide gel electrophoresis. The mutagenesis at His454 has no effects on expression or stability of the protein. The KM values for NADH and 2-oxoglutarate were 1.5-fold and 2.5-fold greater, respectively, for the mutant GDH than for wild-type GDH, indicating that substitution at position 454 had appreciable effects on the affinity of the enzyme for both NADH and 2-oxoglutarate. The Vmax values were similar for wild-type and mutant GDH. The kcat/KM value of the mutant GDH was reduced up to 2.8-fold. The decreased efficiency of the mutant, therefore, results from the increase in KM values for NADH and 2-oxoglutarate. The results with cassette mutagenesis and HPLC gel filtration analysis suggest that His454 is involved in the polymerization process of human GDH

Design of a dye-doped liquid crystal cell with a constant transmittance-difference contour map

Thus far, the trial-and-error method has been used to find the condition for a dye-doped liquid crystal cell with desired performances. In this paper, we report a systematic design process to find the condition for the desired performances without trial-and-error process

Endoscopic Submucosal Dissection versus Surgery for Undifferentiated-Type Early Gastric Cancer: A Systematic Review and Meta-Analysis

Background/Aims The use of endoscopic submucosal dissection (ESD) for treating undifferentiated-type early gastric cancer is controversial. The objective of this study was to perform a meta-analysis to compare the long-term outcomes of ESD and surgery for undifferentiated-type early gastric cancer. Methods The PubMed, Cochrane Library, and EMBASE databases were used to search for relevant studies comparing ESD and surgery for undifferentiated-type early gastric cancer. The methodological quality of the included publications was evaluated using the Risk of Bias Assessment tool for Nonrandomized Studies. The rates of overall survival, recurrence, adverse event, and complete resection were determined. Odds ratios (ORs) and 95% confidence intervals (CIs) were also evaluated. Results This meta-analysis enrolled five studies with 429 and 1,236 participants undergoing ESD and surgery, respectively. No significant difference was found in the overall survival rate between the ESD and surgery groups (OR, 2.29; 95% CI, 0.98–5.36; p=0.06). However, ESD was associated with a higher recurrence rate and a lower complete resection rate. The adverse event rate was similar between the two groups. Conclusions ESD with meticulous surveillance esophagogastroduodenoscopy may be as effective and safe as surgery in patients with undifferentiated-type early gastric cancer. Further large-scale, randomized, controlled studies from additional regions are required to confirm these findings

Enhancement of seawater corrosion resistance in copper using acetone-derived graphene coating

We show that acetone-derived graphene coating can effectively enhance the corrosion efficiency of copper (Cu) in a seawater environment (0.5-0.6 M (???3.0-3.5%) sodium chloride). By applying a drop of acetone (???20 ??l cm-2) on Cu surfaces, rapid thermal annealing allows the facile and rapid synthesis of graphene films on Cu surfaces with a monolayer coverage of almost close to ???100%. Under optimal growth conditions, acetone-derived graphene is found to have a relatively high crystallinity, comparable to common graphene grown by chemical vapor deposition. The resulting graphene-coated Cu surface exhibits 37.5 times higher corrosion resistance as compared to that of mechanically polished Cu. Further, investigation on the role of graphene coating on Cu surfaces suggests that the outstanding corrosion inhibition efficiency (IE) of 97.4% is obtained by protecting the underlying Cu against the penetration of both dissolved oxygen and chlorine ions, thanks to the closely spaced atomic structure of the graphene sheets. The increase of graphene coating thickness results in the enhancement of the overall corrosion IE up to ???99%, which can be attributed to the effective blocking of the ionic diffusion process via grain boundaries. Overall, our results suggest that the acetone-derived graphene film can effectively serve as a corrosion-inhibiting coating in the seawater level and that it may have a promising role to play for potential offshore coating.close0

Endometrioid Adenocarcinoma in Urethrovaginal Septum: A Diagnostic Pitfall

Primary endometrioid adenocarcinoma developed at urethrovaginal septum has not been reported. A 61-yr-old woman presented with recurrent urinary tract infection. She had received hormone replacement treatment with estrogen and progesterone for 5 yr. A pinpoint ulceration at slightly elevated anterior vaginal wall was found and biopsy revealed endometrioid adenocarcinoma. Magnetic resonance imaging showed the 4.3 cm sized mass in urethrovaginal septum. She has undergone anterior pelvic exenteration, pelvic lymph node dissection, and urostomy with ileal conduit. Microscopic finding of the pathology revealed endometrioid adenocarcinoma. Co-existence of endometriosis was not identified. Tumor at urethrovaginal septum was difficult to be detected till growing to be bulky, because of vaginal axis, misunderstanding of the tumor as symphysis pubis, no definitive symptom, and its rarity. This is the first reported case of extraovarian endometrioid adenocarcinoma developed at the urethrovaginal septum. Understanding normal functional anatomy and meticulous physical examination are essential to detect this rare tumor in the urethrovaginal septum

Venous Thromboembolism in Korean Patients Undergoing Major Orthopedic Surgery: A Prospective Observational Study using Computed Tomographic (CT) Pulmonary Angiography and Indirect CT Venography

In patients undergoing major orthopedic surgery, data of deep venous thrombosis (DVT) and pulmonary embolism (PE) are lacking as studied by computed tomographic (CT) pulmonary angiography and indirect CT venography (CTPA-CTV). A prospective observational study was performed for 363 Korean patients undergoing major orthopedic surgery to determine the incidence of venous thromboembolism (VTE), especially proximal DVT and PE. The incidence of VTE was 16.3% (n=59). Of them, 8 patients (2.2%) were symptomatic. The rate of VTE was the highest in patients who underwent total knee replacement (40.4%), followed by hip fracture surgery (16.4%), and total hip replacement (8.7%; P<0.001). The incidence of PE was 6.6% (n=24). Of them, 4 patients (1.1%) were symptomatic. Forty-one patients (11.3%) were in the proximal DVT or PE group. Based on multivariate analysis, total knee replacement and age ≥65 yr were significant risk factors for proximal DVT or PE in patients undergoing major orthopedic surgery (odds ratio [OR], 2.4; 95% confidence interval [CI], 1.1-5.1; P=0.025; and OR, 2.1; 95% CI, 1.0-4.4; P=0.046, respectively). Taken together, the overall incidence of PE was 6.6% and rate of symptomatic PE rate was 1.1%. Knee joint replacement and age ≥65 yr were significant risk factors for proximal DVT or PE