Structure and function of the thermostable L-asparaginase from Thermococcus kodakarensis.

L-Asparaginases catalyse the hydrolysis of asparagine to aspartic acid and ammonia. In addition, L-asparaginase is involved in the biosynthesis of amino acids such as lysine, methionine and threonine. These enzymes have been used as chemotherapeutic agents for the treatment of acute lymphoblastic leukaemia and other haematopoietic malignancies since the tumour cells cannot synthesize sufficient L-asparagine and are thus killed by deprivation of this amino acid. L-Asparaginases are also used in the food industry and have potential in the development of biosensors, for example for asparagine levels in leukaemia. The thermostable type I L-asparaginase from Thermococcus kodakarensis (TkA) is composed of 328 amino acids and forms homodimers in solution, with the highest catalytic activity being observed at pH 9.5 and 85°C. It has a Km value of 5.5 mM for L-asparagine, with no glutaminase activity being observed. The crystal structure of TkA has been determined at 2.18 Å resolution, confirming the presence of two α/β domains connected by a short linker region. The N-terminal domain contains a highly flexible β-hairpin which adopts `open' and `closed' conformations in different subunits of the solved TkA structure. In previously solved L-asparaginase structures this β-hairpin was only visible when in the `closed' conformation, whilst it is characterized with good electron density in all of the subunits of the TkA structure. A phosphate anion resides at the active site, which is formed by residues from both of the neighbouring monomers in the dimer. The high thermostability of TkA is attributed to the high arginine and salt-bridge content when compared with related mesophilic enzymes

Reliable Self-Deployment of Cloud Applications

International audienceCloud applications consist of a set of interconnected software elements distributed over several virtual machines, themselves hosted on remote physical servers. Most existing solutions for deploying such applications require human intervention to configure parts of the system, do not respect functional dependencies among elements that must be respected when starting them, and do not handle virtual machine failures that can occur when deploying an application. This paper presents a self-deployment protocol that was designed to automatically configure a set of software elements to be deployed on different virtual machines. This protocol works in a decentralized way, i.e., there is no need for a centralized server. It also starts the software elements in a certain order, respecting important architectural invariants. This protocol supports virtual machine and network failures, and always succeeds in deploying an application when faced with a finite number of failures. Designing such highly parallel management protocols is difficult, therefore formal modeling techniques and verification tools were used for validation purposes. The protocol was implemented in Java and was used to deploy industrial applications

A Critical Analysis Of Collaborative And Disruptive Digital-Driven Built Environment Education

The Covid-19 pandemic has driven the teaching and learning provisions more towards virtual platforms, exposing lack of resilience and technology preparedness. This study aims to provide a critical appraisal of existing pedagogical studies on built environment (e.g., Building Information Modelling or BIM) challenging the opportunism and agency theories in response towards remote education provision provoked by the pandemic. The study consists of critical review of two literature samples, namely how the education sector as a whole has been responding to the pandemic, and the digitalisation-based pedagogy in built environment especially how the pedagogy addresses the pandemic. The review of the second literature sample evaluates longitudinally how BIM-based built environment education had evolved. A conceptual framework incorporating multiple factors from the review of the two literature samples is finally proposed. These factors include educational theories (e.g., Bloom’s Taxonomy), curriculum development addressing assessment, student experience, collaborative learning, delivery approaches, and teaching methods. This review-based study not only provides an overview of the digital built environment pedagogical work in higher education, but also contests the opportunism response to remote or blended learning and how the post-pandemic era could embrace the remote delivery-platforms to engender a variety of pedagogical principles, for example, cross-disciplinary team-based information sharing, experiential learning, and project-based learning. The findings of this study represent a barometer and roadmap for measuring the resilience of higher education and built environment programmes towards pandemic and technological disruptions

An Investigation into the Critical Factors of on-site Waste Segregation in the UK Construction and Demolition Sector.

This paper provides an in-depth exploration into critical factors affecting the use of on-site waste segregation strategies in the UK C&D market. Utilising data from two separate survey questionnaires; this study confirms usage of on-site segregation strategies by many UK contractors where physical site space and project budgets allow. However, through assessment of stakeholder perceptions, this paper also identifies several key barriers that are impeding overall effectiveness. Amongst many factors, this study indicates how issues such as poor attitude and a lack of knowledge of the benefits amongst workers, could be having a profound effect on successful adaptation of ground level recycling initiatives. This research project then finishes by ranking existent barriers by importance, with the goal of suggesting proposals for overcoming these challenges. Ultimately, weighing the critical factors and prospective barriers to on-site segregation in the UK C&D sector, this study makes recommendation of multiple incentives, but suggests that enhanced training initiatives could be a crucial element for instigating long-term industry improvement in respect of recycling and on-site waste segregation strategies

Commissioning and First Operation of the Antiproton Decelerator (AD)

The Antiproton Decelerator (AD) is a simplified source of antiprotons which provides low energy antiprotons for experiments, replacing four machines: AC (Antiproton Collector), AA (Antiproton Accumulator), PS and LEAR (Low Energy Antiproton Ring), shutdown in 1996. The former AC was modified to include deceleration and electron cooling. The AD started operation in July 2000 and has since delivered cooled beam at 100 MeV/c (kinetic energy of 5.3 MeV) to 3 experiments (ASACUSA, ATHENA and ATRAP) for 1500 h. The flux (up to 2.5´105pbars /s delivered in short pulses of 330 ns every 110 s) and the quality of the ejected beam are not far from the design specifications. A linear RF Quadrupole Decelerator (RFQD) was commissioned in November 2000 to post-decelerate the beam for ASACUSA from 5.3 MeV to about 15 keV. Problems encountered in converting the fixed energy AC into a decelerating machine will be outlined, and the present status of the AD, including the performance of the cooling systems and the special diagnostics to cope with beams of less than 107 pbars, will be reviewed. Possible future developments will be sketche

LHC Magnet Tests: Operational Techniques and Empowerment for Successful Completion

The LHC magnet tests operation team developed various innovative techniques, particularly since early 2004, to complete the superconductor magnet tests by Feb. 2007. Overall and cryogenic priority handling, rapid on-bench thermal cycling, rule-based goodness evaluation on round-the-clock basis, multiple, mashed web systems are some of these techniques applied with rigour for successful tests completion in time. This paper highlights these operation empowerment tools which had a pivotal role for success. A priority handling method was put in place to enable maximum throughput from twelve test benches, having many different constraints. For the cryogenics infrastructure, it implied judicious allocation of limited resources to the benches. Rapid On-Bench Thermal Cycle was a key strategy to accelerate magnets tests throughput, saving time and simplifying logistics. First level magnet appraisal was developed for 24 hr decision making so as to prepare a magnet further for LHC or keep it on standby. Web based systems (Tests Management and E-Traveller) were other essential ideas to track & coordinate various stages of tests handled by different teams

Hepatocellular carcinoma in Pakistan: where do we stand?

Context: From the 1970s till the mid 1990s, hepatitis B was the most common etiological factor for hepatocellular carcinoma (HCC) in Pakistan. Afterwards, a shift in HCC etiology was observed with a steady rise in hepatitis C virus (HCV) related HCC cases. HCV-3a, which is the most prevalent genotype, is also most frequent in HCV related HCC. There was an increase in the proportion of non-B non-C (NBNC) HCC cases as well, which might be attributed to an increase in non-alcoholic fatty liver disease. Evidence Acquisition: The age-standardized rate for HCC is 7.64/100 000 in males and 2.8/100 000 in females. Male to female ratio is 3.6:1. Usual age of presentation is in the fifth and sixth decade. Most patients present with advanced disease, as they are not in a regular surveillance program. This is more so for patients with NBNC chronic liver disease. As many sonologists in Pakistan are practicing without sufficient training to pick up early lesions, alpha-fetoprotein is still recommended to compliment ultrasound in the surveillance of HCC. Results: Majority of HCC patients present with nonresectable disease. Interventions such as transarterial chemoembolization, radiofrequency ablation, resection and chemotherapy including sorafenib are available in selected centers. Pakistan appears to be in an area of intermediate endemicity for HCC. There is a need for population based epidemiological studies to estimate the exact disease burden. Conclusions: Measures to prevent the spread of hepatitis C and B can slow down the epidemic rise in the incidence of HCC in the coming decades. There is a need to implement a proper surveillance program to identify HCC cases at an early stage

Aflatoxin M1 in Nili-ravi buffaloes and its detoxification using organic and inorganic toxin binders

ΔΕΝ ΥΠΑΡΧΕΙ ΠΕΡΙΛΗΨΗThe present study had two objectives: first, to determine the carry over or excretion percentage of aflatoxin B1 (AFBI) in milk in form of aflatoxin M1 (AFM1) and second, to assess the reduction in excretion of AFM1 in milk using different organic and inorganic toxin binders available in Pakistani market. Lactating Nili-Ravi buffaloes (n=16) were randomly selected and were divided into four treatment groups designated as A, B, C and D. In each treatment 500 μg/Kg of aflatoxin B1 (AFB1) was fed along with no sequestering agent added (control); and three toxin binders: Fixar Viva in group B, Mycosorb in group C and T5X in group D. These toxin binders were added at concentration of 0.25% of dry matter intake of animal. It resulted in 2.13% carryover in milk as AFM1. A significant reduction (P<0.05) in dry matter intake, milk production, milk fat and protein percentage was also observed by feeding AFB1. Addition of three toxin binders Mycosorb, Fixar Viva, and T5X at a concentration of 0.25% in ration resulted in 47%, 39%, and 35% reduction in AFM1 secretion respectively. The present study also indicated that percentage carryover ofAFM1 in buffaloes is higher than that reported in lactating cows as well as in goats and Mycosorb is capable of reducing the excretion of AFM1 into milk by improving the dry matter intake, milk production and protein contents. These findings may be applicable in field to reduce AFM1 release in milk of Nili-Ravi buffaloes

Correlation, agreement and concordance of cardiac output estimated by transthoracic ultrasound and transesophageal Doppler with pulmonary artery thermodilution in anesthetized cats

ObjectiveTo characterize the correlation, agreement and concordance of cardiac output (CO) measured with transthoracic ultrasound and the correlation and concordance of aortic blood flow (ABF) minute distance (MD) measured by transesophageal Doppler with CO measured by pulmonary artery thermodilution (PATD) in cats.Study designExperimental study.AnimalsA group of six healthy male neutered cats, aged 2-8 years and weighing 5.3 ± 0.3 kg.MethodsCats were anesthetized with isoflurane in oxygen. CO was measured by PATD (COPATD) and transthoracic echocardiography (COECHO). ABF MD was measured using an esophageal Doppler flow probe aligned with descending ABF. All measurements were made under three conditions: dexmedetomidine (20 μg kg-1) intravenously; atipamezole (200 μg kg-1) intramuscularly and atropine (20 μg kg-1) intravenously as needed to achieve a minimum heart rate of 140 beats minute-1; and dopamine (20 μg kg-1 minute-1) intravenously in that order. Correlation between COPATD and COECHO, and COPATD and Doppler MD was evaluated using repeated measures correlation. Agreement between COPATD and COECHO was evaluated using Bland-Altman method. Differences between consecutive pairs of CO measurements were calculated for concordance analysis.ResultsCorrelation between COPATD and COECHO and between COPATD and MD was significant (p < 0.001), with correlation coefficients greater than 0.92. A bias of > 27% and upper limits of agreement of 66% were found between COPATD and COECHO. Concordance rate with COPATD was 76-80% for COECHO and 72% for MD.Conclusions and clinical relevanceEchocardiographic methods for the measurement of CO showed poor agreement and concordance with PATD. MD showed poor concordance with PATD. As such, these methods cannot be used as an alternative to PATD nor can they appropriately track changes in CO in anesthetized cats