Energy-efficient directional routing between partitioned actors in wireless sensor and actor networks

Actor?actor communication is an important part of the functioning of wireless sensor?actor networks and enables the actor nodes to take coordinated action on a given event. Owing to various reasons such as actor mobility and low actor density, the actor network tends to get partitioned. The authors propose to use the underlying sensor nodes, which are more densely deployed, to heal these partitions. In order to maximise the utilisation of the limited energy available with the sensor nodes, a new routing protocol for actor?actor communication using directional antennas on the actor nodes is proposed. The authors contribution is threefold. First, using simulations they show that the problem of partitioning in the actor networks is significant and propose an architecture with directional antennas on actor nodes and sensor bridges to heal these partitions. Second, they identify the routing problem for this architecture based on a theoretical framework and propose centralised as well as distributed solutions to it. Third, they develop a routing protocol based on the distributed solution and show, using network simulations, that the proposed protocol not only heals the network partitions successfully, but also achieves high throughput and fairness across different flows, in addition to maximising the network lifetime.     

Derivatization of ethinylestradiol with dansyl chloride to enhance electrospray ionization: application in trace analysis of ethinylestradiol in rhesus monkey plasma

The extensive metabolism and administration of low doses of ethinylestradiol (EE) in preclinical animal species necessitates a sensitive analytical method to quantify the drug at low picogram-per-milliliter concentrations in biological matrixes. A highly sensitive and accurate method based on the derivatization of EE with dansyl chloride coupled with liquid chromatography/tandem mass spectrometry is described. The dansyl derivatization of EE introduced a basic secondary nitrogen into the molecule that was readily ionized in commonly used acidic HPLC mobile phases. The derivative showed an intense protonated molecular ion at m/z 530 under positive turbo ion spray ionization. The collision-induced dissociation of this ion formed a distinctive product at m/z 171, corresponding to the protonated 5-(dimethylamino)naphthalene moiety. The selected reaction monitoring, based on the m/z 530 --> 171 transition, was highly specific for EE, since no background signal was observed from blank plasma obtained from rhesus monkeys. The limit of detection, at a signal-to-noise ratio of 5, was 0.2 fg/mL EE spiked into blank plasma. This allowed for a lower limit of quantitation of 5 pg/mL using a 50-microL plasma sample and 10-microL injection of dansylated derivative into the CTC-PAL Leap autosampler coupled to a Sciex API 4000 mass spectrometer. Using fast-gradient liquid chromatography, the analyte peak eluted at 1.6 min. The validation results showed high accuracy (% bias < 4) and precision (% CV < 7.5) at broad linear dynamic ranges (0.005-20 ng/mL), using deuterated EE as internal standard. Therefore, the facile dansyl derivatization coupled with tandem mass spectral analysis allowed the development of a highly sensitive and specific method for quantitation of trace levels of EE in the plasma of rhesus monkeys dosed orally and intravenously with EE.     

Performance models for network processor design

To provide a variety of new and advanced communications services, computer networks are required to perform increasingly complex packet processing. This processing typically takes place on network routers and their associated components. An increasingly central component in router design is a chip-multiprocessor (CMP) referred to as "network processor" or NP. In addition to multiple processors, NPs have multiple forms of on-chip memory, various network and off-chip memory interfaces, and other specialized logic components such as CAMs (content addressable memories). The design space for NPs (e.g., number of processors, caches, cache sizes, etc.) is large due to the diverse workload, application requirements, and system characteristics. System design constraints relate to the maximum chip area and the power consumption that are permissible while achieving defined line rates and executing required packet functions. In this paper, an analytic performance model that captures the processing performance, chip area, and power consumption for a prototypical NP is developed and used to provide quantitative insights into system design trade offs. The model, parameterized with a networking application benchmark, provides the basis for the design of a scalable, high-performance network processor and presents insights into how best to configure the numerous design elements associated with NPs.     

Disk drive control: The early years

One of the persistently exciting control applications is that of disk drive servos. From the start in the early 1950s to the massive capacity commodity drives of the early 2000s, the problem of accessing data on rotating disk media has provided a wealth of control challenges to be solved. This survey paper traces the early history of disk drive control from the first disk drive in 1956 to the first commercial drive with Magneto-Resistive heads in 1990. Rather than the approach used in (Abramovitch and Franklin, 2002a) in which the histories of the components were outlined first, we will focus on the feedback loop itself in those early days. The paper will survey the different areas of the disk drive control problem and how they evolved.     

Sex-and age-related differences in ceramide dihexosides of primary human brain tumors

Neutral glycolipids (NGL) are promising diagnostic markers of human gliomas, but differences in NGL with age and sex have not been examined. Previous work demonstrated that ceramide dihexosides (CDH) levels in mouse kidney are age- and sex-dependent, probably due to levels of sex hormones. We quantitated CDH in 181 human gliomas and found significant differences with sex and age, particularly menopause and male puberty. This emphasizes the importance of assessing results of studies on glycolipids in disease states with respect to age and sex in order to avoid erroneous conclusions concerning the relationship of glycolipid composition with diagnosis and pathogenesis.     

Chromosomal duplication accompanies allelic loss in non-small cell lung carcinoma

Hemizygous deletion in the short (p) arm of chromosome 3 is a common finding in non-small cell lung carcinoma (NSCLC) and is postulated to be a crucial early change in lung tumorigenesis. Yet one of the most frequent nuclear abnormalities in both NSCLC and premalignant bronchial epithelium is increase in chromosomal copy number. Deletion and duplication have not been assessed in the same tumor set by both molecular and cytogenetic methods to determine whether allelic loss correlates with chromosomal duplication in the same tumor cell populations. It is also not established what biological mechanisms might lead to allelic deletion and chromosomal duplication. We have investigated changes in the copy number of chromosome 3 in touch preparations of 38 NSCLCs (19 adenocarcinomas and 19 squamous cell carcinomas) using dual-target, dual-color fluorescence in situ hybridization (FISH) assays. Chromosome 3 centromere probe was matched with a 3p14.2 probe [intron 4 of the fragile histidine triad (FHIT) gene] and a 3p21.31 probe (HSemaIV gene). We then correlated FISH results with results of molecular analyses for allelic losses at loci in the regions to which the FISH probes mapped in 20 of these cases. Although various combinations of FISH abnormalities were sometimes detected within the same specimens, individual cases could be classified according to the predominant FISH pattern, usually with one abnormality present in >60% of tumor cells. Chromosomal duplication, indicated by the presence of more than two centromeric signals, was the most frequent abnormality observed by FISH and was accompanied by loss of specific sequences on 3p in approximately one-half of the specimens in which it was observed. The most frequent abnormality observed by molecular analysis was loss of heterozygosity (LOH) in both of the chromosomal regions tested and was demonstrated in 83% of cases with chromosomal duplication. We conclude that LOH may occur in the presence of chromosomal duplication, suggesting that the duplicated chromosome is homozygous. Our findings imply that LOH occurs before chromosomal duplication during lung carcinogenesis.     

A new source of X-ray line broadening: inhomogeneous strains induced by uniform homogeneous temperature conditions in polyphase or non-cubic materials

Thermal strains may contribute to X-ray diffraction line broadening in both single-phase non-cubic and in polyphase cubic polycrystalline materials even under uniform temperature conditions. A method is developed for calculating the magnitude of these thermally induced strains directly from the measured diffraction peak profiles. Corrections for particle-size effects can be made readily if particle-size broadening is significant, and the thermal diffuse scattering (TDS) contribution to the diffracted intensity can be taken into account experimentally. By this method, the strains in a Mg-5 wt% Si alloy were found to be increased by as much as 35% by a 190° C temperature change. Even in the case of this relatively low melting point alloy, the TDS effect causes only a maximum of 15% error in these measured strain effects. The interpretation of these isothermally induced strains in terms of crystal anisotropy, grain morphology and orientation and the relative sizes of phases and grains is discussed.     

Experimental observations of chemical and thermal gradients in an experimental BOF

The objective of this investigation was to determine the chemical and thermal gradients during steel making in a pilot size basic oxygen furnace. It was postulated that if these gradients could be determined under different conditions, conflicting theories of operation could be tested and optimum operating conditions would be indicated. New sample probe techniques were developed in which the probes are inserted through the side of the vessel to desired locations. Shortly after reaching the desired locations, the tip of an evacuated tube inside the probe opens and delivers metal to the other end of the probe outside the vessel. Temperatures were determined throughout the bath by specially reinforced but sensitive thermocouple probes. Important differences in both chemical and thermal gradients were found. The gradients were greatest with shallow penetration of the jet-for example after 3 min in a heat with about 1 in. penetration, the P content varied from 0.05 to 0.17 pct, silicon from 0.05 to 0.20 pct and the temperature from 2500° to 2900° F. These variations were found in a bath only 6 in. deep and 15 in. diam. By contrast, with deeper jet penetration to the center of the bath, the gradients were greatly reduced. Regardless of the operating conditions employed, the data indicate a metal circulation pattern which is upward from the jet cavity and radially outward at the surface. Even more important, by inserting a spray collector above the bath, it was found that with hard blowing the jet pumps out a volume of droplets during a heat which is equal to the bath volume. These droplets are rapidly oxidized,e.g. from 3.6 to 0.4 pct C, in their flight above the bath and are an important consideration in refining.