Identification and Quantification of Protein Carbonylation by Mass Spectrometry

Accumulated evidence indicates oxidative stress plays important roles in disease and aging. Under oxidative stress, lipid peroxidation (LPO) leads to reactive carbonyl species (RCS) that can modify a wide range of biomolecules including protein, DNA and carbohydrate. In this dissertation, we investigate the modification of two model proteins, human serum albumin (HSA) and aconitase (ACO), by the LPO-relevant a, b-unsaturated aldehydes, acrolein (ACR) and 4-hydroxy-2-nonenal (HNE). The investigation is focused on the characterization and quantification ACR and HNE addition to the model proteins. A correlation between HNE modification and ACO activity is also determined. These results provide insights into the impact of oxidative stress at the molecular level and are relevant to aging and disease states. We finally investigate protein carbonylation in ischemic mouse heart mitochondria, and develop a quantitative method for detecting carbonylated protein in this system. The research is based on liquid chromatography/mass spectrometry (LC/MS), Western Blots, and enzymatic assay

Design of autonomous robot device for accurate pacing of track athletes

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (leaf 42).Given the health and weight gain concerns plaguing the country, there is currently a great need for products that encourage athletic activity. A robotic pacing device that facilitates running along a track was developed to help fulfill this requirement. The need for this device, determined from interviews and a survey of experienced running athletes and coaches, was found to be substantial for a number of age groups and experience levels of runners. An experimental robot prototype was designed and manufactured to aid in pacing runners around a track. The robot was designed to accurately follow the lines of the track using IR sensors that detect reflectivity of the track's surface. The prototype was tested and optimized to determine a successful control logic that reduced error and the amount of overshoot the robot experiences as it adjusts to follow the lines at high speeds. Large overshoots lead to robot malfunction and breakdown in the logic as the robot reaches curves in the track. The optimized prototype currently has the capability of running full lengths around various shaped tracks that incorporate white lines dividing dark colored lanes at speeds of up to eight miles per hour. In this form, the robot might be useful for beginner runners, runners that are doing distance training, and physical education classes that have access to running tracks. Future versions of the robot pacing device will need to incorporate additional features in order to be useful for the full range of people that want to use this product, including a flexible user interface that allows users to program the robot to their needs, a more sophisticated robot control system that allows for accurate control based on the dynamics of the robot, and a more durable cover that is easily spotted by runners looking straight ahead.by Qinyuan (Chen) Liu and Albert Hernandez.S.B

Using gyro stabilizer for active anti-rollover control of articulated wheeled loader vehicles

Articulated wheeled loader vehicles have frequent rollover accidents as they operate in the complex outdoor environments. This article proposes an active anti-rollover control method based on a set of single-frame control moment gyro stabilizer installed on the rear body of the vehicle. The rollover dynamic model is first established for articulated wheeled loader vehicle with gyro stabilizer. The proposed control strategy is then applied in simulation to verify the rollover control effect on the vehicle under steady-state circumferential conditions. Finally, a home-built articulated wheel loader vehicle with gyro stabilizer is used to further verify the proposed control strategy. The results show that the vehicle can quickly return to the stable driving state and effectively avoid the vehicle rollover when a suitable anti-roll control moment can be provided by the gyro stabilizer. As a result, the articulated wheeled loader vehicle is able to operate safely in a complex outdoor environment

Processing of novel grammatical features during real-time second language production and comprehension

Second language (L2) learners often have difficulties acquiring grammatical features which do not exist in their first language (e.g. inflectional morphology, number agreement etc.), and exhibit real-time production and comprehension errors when these features are involved. What are the causes behind such errors? Moreover, what do they tell us about second language processing in general? The primary aim of this thesis was to examine the nature of second language production errors and to scrutinise them with reference to each stage of accepted models of language production, specifically, whether there are consistent error patterns which reveal the source(s) of erroneous production in L2 learners. The second aim of this thesis was to examine the comprehension of novel grammatical features in the second language, more specifically, whether L2 learners could acquire the ability to consistently apply L2 grammatical knowledge relating to newly acquired grammatical features in real-time. The third aim of this thesis was to examine whether L2 learners have fundamental perceptual deficiencies or biases concerning selective L2 phonological features as a result of first language experience, and whether this would affect the perception of specific grammatical features in the L2. This thesis addressed these questions in seven experiments by examining the acquisition of inflectional morphology among L1 Mandarin speakers of L2 English. Experiments 1, 2 and 3 investigated spoken and written production of inflectional morphology via an elicited production paradigm. The results argued against representational accounts and supported activation processing accounts of erroneous second language production. Information complexity and production modality were also found to contribute to low production accuracy. Experiments 4 and 5 investigated L2 learners’ auditory and visual sensitivity to inflectional omissions using self-paced listening and self-paced reading paradigms, where auditory cues were found to facilitate the detection of inflectional omissions. Experiments 6 and 7 investigated perceptual sensitivity to phonologically variable inflectional morphemes in an auditory discrimination paradigm. Second language learners exhibited no perceptual deficiency to novel phonological features, and no consistent perceptual biases favouring L1 phonological features relative to native speakers. Taking these findings as whole, the results favoured a processing account of errors in language production and comprehension, whilst recognising the role of phonological constraints in both processes. Importantly, these conclusions are drawn from a broad analysis of multiple aspects of language processing, recognising the role of conceptual distinctions, grammatical representations, lexical forms, and phonological factors in second language production and comprehension. Additionally, this thesis recognises the value of both psycholinguistic models of language processing and linguistic theories of second language processing

Very high cycle fatigue behavior of bridge steel welded joint

AbstractVery high cycle fatigue (VHCF) behaviors of bridge steel (Q345) welded joints were investigated using an ultrasonic fatigue test system at room temperature with a stress ratio R = −1. The results show that the fatigue strength of welded joints is dropped by an average of 60% comparing to the base metal and the fatigue failure still occurred beyond 107 cycles. The fatigue fracture of welded joints in the low cycle regime generally occurred at the solder while at the heat-affected zone (HAZ) in the very high cycle regime. The fatigue fracture surface was analyzed with scanning electron microscopy (SEM), showing welding defects such as pore, micro-crack and inclusion were the main factors on decreasing the fatigue properties of welded joints. The effect of welding defects on the fatigue behaviors of welded joints was discussed in terms of experimental results and finite element simulations

Decentralized Control for Discrete-time Mean-Field Systems with Multiple Controllers of Delayed Information

In this paper, the finite horizon asymmetric information linear quadratic (LQ) control problem is investigated for a discrete-time mean field system. Different from previous works, multiple controllers with different information sets are involved in the mean field system dynamics. The coupling of different controllers makes it quite difficult in finding the optimal control strategy. Fortunately, by applying the Pontryagin's maximum principle, the corresponding decentralized control problem of the finite horizon is investigated. The contributions of this paper can be concluded as: For the first time, based on the solution of a group of mean-field forward and backward stochastic difference equations (MF-FBSDEs), the necessary and sufficient solvability conditions are derived for the asymmetric information LQ control for the mean field system with multiple controllers. Furthermore, by the use of an innovative orthogonal decomposition approach, the optimal decentralized control strategy is derived, which is based on the solution to a non-symmetric Riccati-type equation

A statistical method to estimate low-energy hadronic cross sections

In this article we propose a model based on the Statistical Bootstrap approach to estimate the cross sections of different hadronic reactions up to a few GeV in c.m.s energy. The method is based on the idea, when two particles collide a so called fireball is formed, which after a short time period decays statistically into a specific final state. To calculate the probabilities we use a phase space description extended with quark combinatorial factors and the possibility of more than one fireball formation. In a few simple cases the probability of a specific final state can be calculated analytically, where we show that the model is able to reproduce the ratios of the considered cross sections. We also show that the model is able to describe proton\,-\,antiproton annihilation at rest. In the latter case we used a numerical method to calculate the more complicated final state probabilities. Additionally, we examined the formation of strange and charmed mesons as well, where we used existing data to fit the relevant model parameters.Comment: 12 pages, 12 figures, submitted to EPJ