Bonding elastomer layers together by a surface oxidation reaction

An experimental study has been carried out of the self-adhesion of thin layes of three crosslinked elastomers: cis-polyisoprene (natural rubber) and two polybutadienes. For the polybutadiene materials, the strength of self-adhesion was found to be strongly dependent upon the time of exposure of the two surfaces to air before they were brought into contact. The strength rose dramatically after the first hour or so of exposure so that in some instances the layers could not be forcibly separated later. When the surfaces were exposed to air for longer periods before joining them, the strength of self-adhesion fell to low levels again. This remarkable enhancement in self-adhesion, caused by prior exposure to air for short periods, did not take place on exposure to nitrogen or for samples of cis-polyisoprene, and it was reduced or delayed in samples containing antioxidant. It is therefore attributed to surface oxidation reactions that can lead to the formation of interfacial covalent bonds with polybutadiene but not with polyisoprene. Some possible reaction schemes are discussed.     

Advance directives and withdrawal of dialysis in the United States, Germany, and Japan

OBJECTIVE: To determine the role of advance directives in decisions to withdraw chronic dialysis in the United States, Germany, and Japan. DESIGN: Survey by questionnaire. PARTICIPANTS: Seventy-two American, 87 German, and 73 Japanese nephrologists. MAIN OUTCOME MEASURES: Each nephrologist's total number of (1) dialysis patients, (2) cases of withdrawal of dialysis, (3) patients with advance directives, and (4) uses of such directives. Nephrologists also stated whether they would continue or stop dialysis in 8 hypothetical cases. RESULTS: American, German, and Japanese nephrologists reported withdrawing dialysis for 5.1%, 1.6%, and 0.7% of their patients in the last year, respectively. Thirty percent of American patients had advance directives, and such directives were used in decision making for 3.2% of all patients. Only 0.3% of German and Japanese patients had advance directives, and such directives were used in decision making for 0.09% of patients. When asked about a hypothetical mentally incompetent patient whose family requests withdrawal of dialysis, American nephrologists were much more likely to stop dialysis in the absence of an advance directive than German or Japanese nephrologists. However, almost all nephrologists from the 3 countries would stop dialysis when a family request to withdraw was supported by a patient advance directive. CONCLUSIONS: There is a high prevalence of advance directives among American dialysis patients, and such directives frequently play a role in decision making. German and Japanese nephrologists appear willing to follow advance directives, but the low prevalence of such directives limits the frequency of their use.     

Recombinant Bombyx mori nucleopolyhedrovirus harboring green fluorescent protein

The gene encoding the green fluorescent protein (gfp) under the control of the highly expressed Autographa californica nucleopolyhedrovirus (AcMNPV)-polyhedrin promoter has been introduced into the polyhedrin (polh) locus of Bombyx mori nucleopolyhedrovirus (BmNPV) by homologous recombination. The insect host larvae and the cultured cells infected with this recombinant virus (vBmGFP) showed high levels of expression of gfp. The larval tissues permissive to virus multiplication could be readily visualized using the tagged recombinant virus, thus providing a direct approach to study the progress of virus infection or its control in the animal host. The highly expressed recombinant protein, GFP, could be easily solubilized from fat bodies. Thus, the caterpillar-based expression could serve as an economic alternative method for the large-scale production of recombinant proteins, even when they are nonsecretory in nature. Further, if the recombinant vBmGFP is used as a parent in generating other recombinants, conversion of the fluorescent plaques to colorless plaques serves as an easy means for screening recombinants. Such a method is especially helpful for BmNPV-recombinant selections in the absence of the other simplified techniques as are available for the prototype baculovirus AcMNPV system.     

Power conscious CAD tools and methodologies: a perspective

Power consumption is rapidly becoming an area of growing concern in IC and system design houses. Issues such as battery life, thermal limits, packaging constraints and cooling options are becoming key factors in the success of a product. As a consequence, IC and system designers are beginning to see the impact of power on design area, design speed, design complexity and manufacturing cost. While process and voltage scaling can achieve significant power reductions, these are expensive strategies that require industry momentum, that only pay off in the long run. Technology independent gains for power come from the area of design for low power which has a much higher return on investment (ROI). But low power design is not only a new area but is also a complex endeavour requiring a broad range of synergistic capabilities from architecture/microarchitecture design to package design. It changes traditional IC design from a two-dimensional problem (Area/performance) to a three-dimensional one (Area/Performance/Power). This paper describes the CAD tools and methodologies required to effect efficient design for low power. It is targeted to a wide audience and tries to convey an understanding of the breadth of the problem. It explains the state of the art in CAD tools and methodologies. The paper is written in the form of a tutorial, making it easy to read by keeping the technical depth to a minimum while supplying a wealth of technical references. Simultaneously the paper identifies unresolved problems in an attempt to incite research in these areas. Finally an attempt is made to provide commercial CAD tool vendors with an understanding of the needs and time frames for new CAD tools supporting low power design     

State observer controller design for packets flow control in networks-on-chip

Packet-switched networks-on-chips (NoCs) are efficient communication architectures for future multiprocessors system-on-chip (MP-SoC) platforms. However the run-time management of their communication, especially flow control from individual intellectual property (IP) in an NoC which contains large number of IPs, is a challenging task. This paper proposes a state space model for NoC with state observer controller in its feedback path. It is seen that controlling the input and output flow rates alone is not sufficient to stabilize the network, but it is also important to monitor the intermediate flow rates from the on-chip routers. This is possible through a state space model for the NoC. The state observer observes the flow rates from each on-chip router which are then treated as state space variables. These variables can be controlled by the poles placement in the feedback controller. The proposed mathematical model can also observe the required intermediate flow rates which cannot be measured directly (reduced state observer). With these observed states we can attach a state controller. With this controller the network can be stabilized by controlling the flow rates at the intermediate level.     

Heat loss optimisation of a concentric cylindrical solar collector employing a cobalt oxide selective absorber

Experimental and theoretical investigations to optimise the geometrical design parameters of a tubular collector under atmospheric and evacuated (～ 10^?3 torr) conditions are reported. The results indicate that a maximum stagnation temperature, which corresponds to the minimum heat loss, is obtained for a gap width of ～ 12 mm. An absorber tube of 35 mm diameter concentric with a cover glass tube of 59 mm diameter was observed to be the best combination. An improvement in the collector performance was observed by increasing the illuminated area of the absorber tube and by evacuating the annular gap in the collector.     

Curcumin and Its Derivatives as Theranostic Agents in Alzheimer’s Disease: The Implication of Nanotechnology

Curcumin is a polyphenolic natural compound with diverse and attractive biological properties, which may prevent or ameliorate pathological processes underlying age-related cognitive decline, Alzheimer’s disease (AD), dementia, or mode disorders. AD is a chronic neurodegenerative disorder that is known as one of the rapidly growing diseases, especially in the elderly population. Moreover, being the eminent cause of dementia, posing problems for families, societies as well a severe burden on the economy. There are no effective drugs to cure AD. Although curcumin and its derivatives have shown properties that can be considered useful in inhibiting the hallmarks of AD, however, they have low bioavailability. Furthermore, to combat diagnostic and therapeutic limitations, various nanoformulations have also been recognized as theranostic agents that can also enhance the pharmacokinetic properties of curcumin and other bioactive compounds. Nanocarriers have shown beneficial properties to deliver curcumin and other nutritional compounds against the blood-brain barrier to efficiently distribute them in the brain. This review spotlights the role and effectiveness of curcumin and its derivatives in AD. Besides, the gut metabolism of curcumin and the effects of nanoparticles and their possible activity as diagnostic and therapeutic agents in AD also discussed.     

A study on gait entropy image analysis for clothing invariant human identification

A simple and common human gait may be viewed as a strong biometric cue to solve human identification problem through understanding the intrinsic patterns of gait biometrics. An individual’s gait pattern appears to be different in gallery and probe gait sequences due to wearing dissimilar clothing types. The gait dataset captures the possible changes found in silhouette shape image which provides the difficulty in distinguishing among individuals. In this paper, a robust feature selection technique has been addressed through Gait Entropy Image (GEnI) analysis. The GEnI has the capacity to accumulate most significant motion information. The width of GEnI, along the horizontal axis is taken as discriminative feature which produces a small intra-class variance. This information is studied as an evidence of feature invariance. The standard statistical tests such as pair-wise clothing correlation and intra-clothing variance are performed on gait dataset to evaluate the reliability of feature. Experimental results demonstrate the efficiency of proposed feature selection method using k-nearest neighbor (k-NN), minimum distance classifier (MDC), and support vector machine (SVM) algorithms. The performance analysis of recognition system has been evaluated on OU-ISIR Treadmill B gait database with different error metrics after performing N-fold cross validation method.     

Modern architecture for photonic networks-on-chip

Development in photonic integrated circuits (PICs) provides a promising solution for on-chip optical computation and communication. PICs provides the best alternative to traditional networks-on-chip (NoC) circuits which face serious challenges such as bandwidth, latency and power consumption. Integrated optics have substantiated the ability to accomplish low-power communication and low-power data processing at ultra-high speeds. In this work, we propose a new architecture for NoC, which might improve overall on-chip network performance by reducing its power consumption, providing large channel capacity for communication, decreasing latency among nodes and reducing hop count. Some of the key features of the proposed architecture are to reduce the waveguide network for communication among nodes, and this architecture can be used as a brick to construct other architectures. In this architecture, we use micro-ring resonator (MRR) and it is used to provide a high bandwidth connection among nodes with a lesser number of waveguide networks. Furthermore, results show that this architecture of PICs provides better performance in terms of low communication latency, low power consumption, high bandwidth. It also provides acceptable FSR value, FWHR value, finesse value and Q-factor of micro-ring resonators used for the design of MRR in this architecture.