Preparation of TEM foils from Nb-10 a/o Si.

Ductile phase toughened composites contain phases with significantly different physical properties. Consequently, these phases thin at different rates depending on the sample preparation procedure. A new TEM foil preparation method for the ductile phase toughened Nb-10 a/o Si material has been developed. The method involves chemical thinning in a 70% nitric acid/30% hydrofluoric acid solution followed by electropolishing in a 12.5% sulfuric acid/87.5% methanol electrolyte at -40 degrees C. This procedure for making TEM foils results in large thin areas with the minimum of artifacts. Mechanical grinding of a sample followed by either ion milling, dimpling, or electropolishing produced foils with large electron transparent areas, but with uncharacteristic features of the original Nb-10 a/o Si alloy microstructure. These artifacts were identified as dislocations, surface mottling, and antiphase domains.     

Actin associates with the nucleocapsid domain of the human immunodeficiency virus Gag polyprotein

Recently, it was shown that actin molecules are present in human immunodeficiency virus type 1 (HIV-1) particles. We have examined the basis for incorporation and the location of actin molecules within HIV-1 and murine retrovirus particles. Our results show that the retroviral Gag polyprotein is sufficient for actin uptake. Immunolabeling studies demonstrate that actin molecules localize to a specific radial position within the immature particle, clearly displaced from the matrix domain underneath the viral membrane but in proximity to the nucleocapsid (NC) domain of the Gag polyprotein. When virus or subviral Gag particles were disrupted with nonionic detergent, actin molecules remained associated with the disrupted particles. Actin molecules remained in a stable complex with the NC cleavage product (or an NC-RNA complex) after treatment of the disrupted HIV-1 particles with recombinant HIV-1 protease. In contrast, matrix and capsid molecules were released. The same result was obtained when mature HIV-1 particles were disrupted with detergent. Taken together, these results indicate that actin molecules are associated with the NC domain of the viral polyprotein.     

Hangover Frequency and Risk for Alcohol Use Disorders: Evidence From a Longitudinal High-Risk Study.

Data from a prospective high-risk study (N=489; 51% with a family history of alcoholism) were used to test whether family history is associated with greater hangover proneness and whether hangover is a risk factor for alcohol use disorders. Hangover was more frequent in family-history-positive participants during the college years. Persons with an alcohol diagnosis showed excess hangover before earning a diagnosis. Year 1 hangover predicted alcohol use disorders at Years 7 and 11, even when family history, sex, Year 1 diagnoses, and Year 1 drinking were statistically controlled. Several nonhangover drinking symptoms failed to predict later diagnoses. Taken together, the findings suggest a need for further research and theory on the role of hangover in the etiology of drinking problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A case for the VMEbus architecture in embedded systems education

The VMEbus is an IEEE standard architecture upon which many embedded and real-time systems are built. The VMEbus architecture has existed for nearly 25 years and has been used extensively for military, industrial, and aerospace applications. This paper describes the general characteristics of the VMEbus architecture, specifically relating these characteristics to aspects of embedded systems education included as components of the IEEE/ACM CE2004 computer engineering model curriculum. Portions of this model curriculum are currently being implemented at universities across the country as part of an increasing effort to address the need for embedded systems education. This evaluation will identify the strengths and weaknesses of this architecture as a general-purpose embedded systems educational tool. The VMEbus architecture is used in the laboratory component of an undergraduate embedded systems course at the University of Alabama (UA), Tuscaloosa. The assessment results evaluating its effectiveness are presented.     

Teaching introductory autonomous robotics with JavaScript simulations and actual robots

This paper describes a flexible method of teaching introductory robotics. Students program an autonomous mobile robot to complete a set of tasks of increasing complexity, including multirobot tracking. Two proximity detectors (1 b each) and a pair of photosensors (2 b each) provide six sensory inputs to logic circuits, which control two drive motors and two internal memory flip-flops. The robot brain is a digital logic circuit programmed by loading an AS CH code that specifies the logic circuit configuration, similar in approach to a field-programmable gate array. The logic circuit design evolves with task complexity. Two internal set/reset flip-flops can be used to design a finite-state machine to implement a memory. One novelty of the method is that students develop and test their logic circuits on a Web-based graphic simulation before downloading the code to an actual robot. The simulation is written in JavaScript to acquire sensor readings and control robot motors to interact with the environment in a flexible manner. The simulation is downloaded with the Web page and runs smoothly on the client's machine, eliminating the need for high-speed connections. The ASCII code producing successful simulation performance is downloaded to an actual robot through a printer port on a PC in the robot laboratory. A microcontroller on the actual robot interprets the ASCII code in the same manner as the simulation. Classroom experience indicates that evolving a robot brain is an effective teaching tool and students enjoy applying logic circuit design to program a robot.