Polar Interactions at the Dimer–Dimer Interface of Methionine Adenosyltransferase MAT I Control Tetramerization

Catalytic MATα1 subunits associate into kinetically distinct homo-dimers (MAT III) and homo-tetramers (MAT I) that synthesize S-adenosylmethionine in the adult liver. Pathological reductions in S-adenosylmethionine levels correlate with MAT III accumulation; thus, it is important to know the determinants of dimer–dimer associations. Here, polar interactions (<3.5 Å) at the rat MAT I dimer–dimer interface were disrupted by site-directed mutagenesis. Heterologous expression rendered decreased soluble mutant MATα1 levels that appeared mostly as dimers. Substitutions at the B1–B2 or B3–C1 β-strand loops, or changes in charge on helix α2 located behind, induced either MAT III or MAT I accumulation. Notably, double mutants combining neutral changes on helix α2 with substitutions at either β-strand loop further increased MAT III content. Mutations had negligible impact on secondary or tertiary protein structure, but induced changes of 5–10 °C in thermal stability. All mutants preserved tripolyphosphatase activity, although AdoMet synthesis was only detected in single mutants. Kinetic parameters were altered in all purified proteins, their AdoMet synthesis Vmax and methionine affinities correlating with the association state induced by the corresponding mutations. In conclusion, polar interactions control MATα1 tetramerization and kinetics, diverse effects being induced by changes on opposite β-sheet loops putatively leading to subtle variations in central domain β-sheet orientation.

Does a delay in surgery for distal radial fractures affect patient outcome?

Current guidelines from the British Orthopaedic Association state that if fractures of the distal radius are operated on then this should take place within 3 days of injury for intra-articular fractures, 7 days for extra-articular fractures and 3 days when a trial of conservative management has failed. This retrospective cohort study aimed to assess whether there was any difference in outcome between patients receiving timely or delayed surgery, using the Patient-Rated Wrist Evaluation score at >12 months after injury as the primary outcome measure. Data from 380 patients treated at two district general hospitals over a 5-year period were obtained using electronic databases to capture the demographics and treatment details and postal questionnaires to assess current function. The study showed no statistical or clinical differences in outcome measures between the timely or delayed cohorts in any of the three treatment groups. Level of evidence: III

An Optimized Tightly-Coupled VIO Design on the Basis of the Fused Point and Line Features for Patrol Robot Navigation

The development and maturation of simultaneous localization and mapping (SLAM) in robotics opens the door to the application of a visual inertial odometry (VIO) to the robot navigation system. For a patrol robot with no available Global Positioning System (GPS) support, the embedded VIO components, which are generally composed of an Inertial Measurement Unit (IMU) and a camera, fuse the inertial recursion with SLAM calculation tasks, and enable the robot to estimate its location within a map. The highlights of the optimized VIO design lie in the simplified VIO initialization strategy as well as the fused point and line feature-matching based method for efficient pose estimates in the front-end. With a tightly-coupled VIO anatomy, the system state is explicitly expressed in a vector and further estimated by the state estimator. The consequent problems associated with the data association, state optimization, sliding window and timestamp alignment in the back-end are discussed in detail. The dataset tests and real substation scene tests are conducted, and the experimental results indicate that the proposed VIO can realize the accurate pose estimation with a favorable initializing efficiency and eminent map representations as expected in concerned environments. The proposed VIO design can therefore be recognized as a preferred tool reference for a class of visual and inertial SLAM application domains preceded by no external location reference support hypothesis.

Time Series Association State Analysis Method for Attacks on the Smart Internet of Electric Vehicle Charging Network

A robust, integrated and flexible charging network is essential for the growth and deployment of electric vehicles (EVs). The State Grid of China has developed a Smart Internet of Electric Vehicle Charging Network (SIEN). At present, there are three main ways to attack SIEN maliciously: distributed data tampering; distributed denial of service (DDoS); and forged command attacks. Network attacks are random and continuous, closely related to time. By contrast, when analyzing the alarm in malicious attacks, the traditional Markov chain based model ignores the association relationship in the time series between states of alarm, so that the analysis and prediction of alarms are not suitable for real situations. This paper analyzes the characteristics of the three types of attack and proposes an association state analysis method on the time series. This method firstly analyzes alarm logs at different locations, different levels, and different types, and then establishes the temporal association of scattered and isolated alarm information. Secondly, it tracks the transition trend of abnormal events in the SIEN’s main station layer, the channel layer, and the sub-station layer. It also identifies the real attack behavior. This method not only provides a prediction of security risks, but, more importantly, it can also accurately analyze the trend of SIEN security risks. Compared with the ordinary Markov chain model, this method can better smooth the fluctuation of processing values, with higher real-time performance, stronger robustness, and higher precision. This method has been applied to the State Grid of China.

Investigation causes of pavement structure failure using new AASHTO mechanistic-empirical procedures for optimization roads performance in different climatic condition of Iran

In recent years, procedure of AASHTO (American Association State Highway and Transportation Officials) Guide for Design of Pavement Structures distanced from first empirical procedure and advanced toward mechanistic-empirical procedures. “Guide for Mechanistic-Empirical Design of New and Rehabilitated Pavement Structures” in 2004 and its attached software M-EPDG is the result of this new procedure that AASHTO presented it through projects NCHRP 1-37 A and NCHRP 1-40 B with cooperation of NCHRP (National Cooperative Highway Research Program) and FHWA (Federal Highway Administration) institutions. In this paper, requireddata for software analyzing of three real pavement structures pieces collected from three different climatic areas and pavement structures modeled in software by entering data into software. Modeled sections by this software were analyzed failure, and, regarding to obtained results, common designing pavement structures procedures compared with the new way of AASHTO, and efficiency rate of related software investigated in two different climatic zone of Iran. Toward this process, Save- Hamadan and Qazvin- Boin Zahra cities selected as a case study and then studied. Results of software analyzing showed that the designs of old AASHTO method in tempered climate of country met all criteria of designing but in both of cold and warm areas, some failure at designed pavement structures via this method exceeded from allowed rate and according to presented failure, will be excessed more in future. This destruction in case project of cold area was longitude crack and was rutting of pavement structures subgrade in warm area. Then, probable causes of mentioned failures studied in pavement structures projects and procedures designed for rehabilitation pavement structures for met all of the designated criteria. Also, in Iran some suggestions indicated about required conductions for application of new method of AASHTO.

Investigation causes of pavement structure destruction using new AASHTO mechanistic-empirical procedures for improving roads function in different climatic condition of Iran

In recent years, procedure of AASHTO (American Association State Highway and Transportation Officials) Guide for Design of Pavement Structures distanced from first empirical procedure and advanced toward mechanistic-empirical procedures. “Guide for Mechanistic-Empirical Design of New and Rehabilitated Pavement Structures” in 2004 and its attached software M-EPDG is the result of this new procedure that AASHTO presented it through projects NCHRP 1-37 A and NCHRP 1-40 B with cooperation of NCHRP (National Cooperative Highway Research Program) and FHWA (Federal Highway Administration) institutions. In this paper, required data for software analyzing of three real pavement structures pieces collected from three different climatic areas and pavement structures modeled in software by entering data into software. Modeled sections by this software were analyzed destructions, and, regarding to obtained results, common designing pavement structures procedures compared with the new way of AASHTO, and efficiency rate of related software investigated in three different climatic areas of Iran. Toward this process, Save, Hamadan and Qazvin, Boin Zahra cities selected as a case study and then studied. Results of software analyzing showed that the designs of old AASHTO method in tempered climate of country met all criteria of designing but in both of cold and warm areas, some destructions at designed pavement structures via this method exceeded from allowed rate and according to presented destructions, will be excessed more in future. This destruction in case project of cold area was longitude crack and was furrowing of pavement structures bed in warm area. Then, probable causes of mentioned destructions studied in pavement structures projects and procedures designed for rehabilitating pavement structures for met all of the designated criteria. Also, in Iran some suggestions indicated about required conductions for application of new method of AASHTO.

Influence of association state and DNA binding on the O2-reactivity of [4Fe-4S] fumarate and nitrate reduction (FNR) regulator

DNA-binding of [4Fe-4S] FNR and amino acid substitutions that decouple the dependence of the association state on the cluster are shown to have no effect on the overall cluster conversion mechanism but have a significant effect on reaction kinetics.