Delta opioid peptide [D-Ala2,D-leu5]enkephalin blocks the long-term loss of dopamine transporters induced by multiple administrations of methamphetamine: involvement of opioid receptors and reactive oxygen species

Delta opioid peptide [D-Ala2,D-leu5]enkephalin (DADLE) can prolong organ preservation and increases myocardial tolerance to ischemia. Our study examined the protective property of DADLE against methamphetamine- (METH) induced dopaminergic terminal damage in the central nervous system. Because the neurotoxicity of METH involves reactive oxygen species, we also examined if DADLE might be an antioxidative agent in vitro. DADLE at 2 and 4 mg/kg (i.p.), given 30 min before each METH administration (5 or 10 mg/kg, i.p., four injections in a day at 2-hr intervals), dose-dependently blocked the METH-induced long-term dopamine transporter loss. The opioid antagonist naltrexone blocked this action of DADLE in both aspects of striata but tends not to affect the effects of DADLE in the nucleus accumbens. DADLE did not alter changes in body temperature induced by METH. The reduction of striatal dopaminergic content and tyrosine hydroxylase activity caused by METH, however, were not blocked by DADLE. In vitro, DADLE was approximately equipotent to glutathione in inhibiting both superoxide anion formation induced by xanthine oxidase and hydroxyl radical formation evoked by ferrous/citrate complex. DADLE was only slightly less potent than glutathione in inhibiting the iron/ascorbate-induced brain lipid peroxidation. These results suggest that DADLE can protect the terminal membranes of dopaminergic neurons against METH-induced insult but not the loss of dopaminergic content and tyrosine hydroxylase activity and that this action of DADLE might involve opioid receptors as well as the sequestration of free radical.     

Small amphiphilic organics, coordination extended solids, and constant curvature structures

In this Account, we explore the role constant curvature structures play in amphiphilic small molecule crystals and extended coordination solids. A constant curvature structure is one in which there is a surface or interface that has the same curvature throughout its surface. Simple examples of such structures contain spheres (micelles), columns, or layers. Yet another family are cubic as is found in the gyroid topology. For amphiphilic systems, there are two domains, one generally hydrophobic and the other hydrophilic. We find that the interfaces between these two domains in small molecule structures resemble those in larger scale systems and adopt topologies related to constant curvature structures. The hydrophobic-to-total volume ratio, a molecular parameter, can be used to predict which type of constant curvature structure is adopted. In the case of three coordinate extended solids, constant curvature plays a role both in the extended net topology and in the hydrophobic-to-hydrophilic interface.     

Zodiac: A history-based interactive video authoring system

Easy-to-use audio/video authoring tools play a crucial role in moving multimedia software from research curiosity to mainstream applications. However, research in multimedia authoring systems has rarely been documented in the literature. This paper describes the design and implementation of an interactive video authoring system called Zodiac, which employs an innovative edit history abstraction to support several unique editing features not found in existing commercial and research video editing systems. Zodiac provides users a conceptually clean and semantically powerful branching history model of edit operations to organize the authoring process, and to navigate among versions of authored documents. In addition, by analyzing the edit history, Zodiac is able to reliably detect a composed video stream's shot and scene boundaries, which facilitates interactive video browsing. Zodiac also features a video object annotation capability that allows users to associate annotations to moving objects in a video sequence. The annotations themselves could be text, image, audio, or video. Zodiac is built on top of MMFS, a file system specifically designed for interactive multimedia development environments, and implements an internal buffer manager that supports transparent lossless compression/decompression. Shot/scene detection, video object annotation, and buffer management all exploit the edit history information for performance optimization.     

Fracture toughness characterization of a PC/ABS blend under different strain rates by various J-integral methods

A published, nonconventional J-integral method, based on the hysteresis energy and the ASTM E813 methods, has been employed to test the fracture toughness of a polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) blend. The critical J values (J_Ic) at crosshead speeds ranging from 0.5 to 20 mm/min obtained from the hysteresis energy method are ∼10 to 20% higher than those obtained from the E813–81 method and ∼50 to 70% lower than those obtained from the E813–87 method. However, the hysteresis energy method results in comparable J_Ic values with a modified ASTM E813–87 method when the 0.2 mm offset line is replaced with a 0.1 mm offset line. The critical displacements in terms of the onset of crack initiation, determined from the plots of hysteresis energy vs. displacement, hysteresis ratio vs. displacement, and the true crack growth length vs. displacement, are fairly close in value. This indicates the critical crack initiation and the corresponding J_Ic obtained from this hysteresis energy method indeed represent the actual physical event of the onset of crack initiation.     

Defect characterization of roller bearing surfaces with laser Doppler vibrometry

Laser Doppler vibrometry is presented as an effective method of surface profile measurement and surface crack detection in rolling bearing balls. For both inspections, a surface velocity profile is used in addition to surface displacement profile. An experimental setup and a signal-processing algorithm are used to obtain digitized surface profiles and power spectral density measurements of ball surfaces. Profile measurements are presented that match lobed ball frequency results with a resolution of 0.025 μm. Velocity measurement provides a much higher bandwidth for defect detection. Cracks down to 22 μm in width can be detected with a 150 μm by 500 μm wide laser spot size. Cracks smaller than 22 μm can be detected by decreasing the laser spot size. The method is well suited for a manufacturing environment because of its durability, simplicity, and high speed.     

Differential wavelength-scanning heterodyne interferometer for measuring large step height

An interferometer based on the differential heterodyne configuration and wavelength-scanning interferometry for measuring large step heights is presented. The proposed interferometer is less sensitive to environmental disturbances than other interferometers and can accurately measure interference phases. A tunable diode laser is utilized to illuminate the interferometer and thus solve the phase ambiguity problem. Counting the interference fringes as the wavelength is scanned through a known change in wavelength directly determines the step height. Three gauge blocks of different lengths, 5, 10, and 50 mm, are individually wrung on a steel plate to simulate large step heights. Comparing the results measured by the proposed interferometer with those by the gauge block interferometer reveals that the accuracy is approximately 100 nm.     

Role of nickel undercoat and reduction-flame heating on the mechanical properties of Cr-C deposit electroplated from a trivalent chromium based bath

In this study, a surface hardening method for Cr-C deposits using flame heating for a short period is proposed. The hardness and wear resistance behavior of as-plated and flame-heated Cr-C deposits were investigated. The Cr-C deposits were electroplated on high carbon tool steel in a bath with trivalent chromium ions. Experimental results show that Cr-C deposits with an extremely high hardness of ca. 1700 Hv can be achieved after reduction-flame heating for 1 s. Meanwhile, the wear resistance of Cr-C deposited steel was improved after flame heating. To increase the wear resistance and bonding strength of the Cr-C deposited specimen, pre-electrodeposition of a thin Ni deposit between the Cr-C deposit and the steel substrate is recommended. A Ni undercoat with a thickness of few micrometers could reduce the crack density in the Cr-C deposit and increase the bonding strength between the Cr-C deposit and the steel substrate. As determined by a microstructure study, the as-plated Cr-C deposit has an amorphous structure, but transforms to a crystalline structure after flame heating. The main hardening mechanism is a result of the precipitation of nanograined diamond membranes, which can be extracted by immersing the flame-hardened Cr-C deposit in an etching solution comprised of 33 vol.% HNO₃ and 67 vol.% HCl.     

Cache memory design for Internet processors

As a result of the exploding bandwidth demand from the Internet, network router and switch designers are designing and fabricating a growing number of microchips specifically for networking devices rather than traditional computing applications. In particular, a new breed of microprocessors, called Internet processors, has emerged that is designed to efficiently execute network protocols on various types of internetworking devices including switches, routers, and application-level gateways. We evaluate a series of three progressively more aggressive routing-table cache designs and demonstrate that the incorporation of hardware caches into Internet processors, combined with efficient caching algorithms can significantly improve overall packet forwarding performance     

Uncertainty in biomass supply estimates: Lessons from a Yakama Nation case study

The increasing demand for bioenergy in the United States necessitates detailed case studies of cost and supply to assess its feasibility. We have developed supply curves based on six feedstocks in five counties surrounding the Yakama Nation in central Washington using spatially explicit estimates of supply and transportation cost. The supply curves were used to examine a base case supply for a bioenergy plant, to analyze the effects of land ownership, and examine the impacts of uncertainty in parameters used to determine cost and supply. The results show that existing industries produce the cheapest supply of feedstock as a byproduct of their operations, while supplies harvested specifically for bioenergy are considerably more expensive. Fragmented land ownerships lead to the necessity of cooperation between owners and highlight the importance of a strong anchor supply close to the plant. Lastly, uncertainty in supply and cost parameters leads to larger ranges in available biomass, leading to reluctant investment in large plants.     

Laboratory Evaluation of Real-Time Dynamic Traffic Assignment Systems

The success of Advanced Traffic Management Systems (ATMS) and Advanced Traveler Information Systems (ATIS) depends on the availability and dissemination of timely and accurate estimates of prevailing and emerging traffic conditions, as well as the provision of faithful and coherent pretrip and en-route travel information and advisory to travelers. Real-time Dynamic Traffic Assignment (DTA) systems, envisioned as an ATMS support system that resides in transportation management centers, are being developed to supply these estimates and information. To ensure the deployment potential of such DTA systems in the field, extensive laboratory evaluations are required throughout the development process. This article discusses a software environment that economically supports the development and evaluation of DTA systems. A major simulation component developed under this environment is called a DTA evaluation system (DES). The DES is a virtual representation of a transportation system in which ATMS and ATIS technologies are deployed. It simulates the trip-making and vehicle-driving behaviors of travelers in response to real-time information and advisories from ATIS and ATMS. This article presents (1) major DES modeling capabilities required for developing and evaluating DTA systems, (2) a modular and extensible modeling framework for the DES, and (3) a top-level, object-oriented, and distributed DES design.