A non-nitrergic smooth muscle relaxant factor released from rat urinary bladder by muscarinic receptor stimulation

PURPOSE: To study the possible release of a relaxant factor from isolated rat bladder tissue. MATERIALS AND METHODS: Thoracic aortae and urinary bladders were obtained from 55 female Sprague-Dawley rats. The bladder body was used in its original tubular shape as the donor tissue in a co-axial bioassay system, and the aorta served as acceptor tissue. RESULTS: In a co-axial bioassay system with endothelium-free, norepinephrine-contracted, rat aortic preparations mounted within urothelium-intact urinary bladder, carbachol caused a concentration-dependent relaxation, amounting to 64+/-7% (n = 10) of the induced contraction, suggesting release of a relaxing factor. The relaxant effect of carbachol was lost if the urinary bladder segment was removed. However, the relaxation was affected neither by removal of the urothelium, nor by bladder segment inversion. It was resistant to inhibition of the L-arginine/nitric oxide and cyclo-oxygenase pathways, and unaffected by beta-adrenoceptor blockade and K+ channel inhibition. The relaxation was not associated with any significant changes in the intracellular levels of cGMP or cAMP. CONCLUSION: A previously unrecognized non-adrenergic, non-nitrergic, non-prostanoid inhibitory mediator is released from the rat urinary bladder by muscarinic receptor stimulation. The physiological importance of such a factor remains to be established.     

8.9-Megapixel Video Image Sensor With 14-b Column-Parallel SA-ADC

An 8.9-megapixel 60-frames/s video image sensor with a 14-b column-parallel analog-to-digital converter (ADC) has been developed. A gain amplifier, a 14-b successive approximation ADC (SA-ADC), and a new column digital processor are employed in each column. The SA-ADC has sufficient operation speed to convert the pixel reset and the pixel signal into digital data in a row operation cycle. The column digital processor receives bit serial data from the SA-ADC output and performs subtraction of the reset data from the signal data in order to reduce column fixed pattern noise (FPN). Column FPN is successfully reduced to 0.36 e_rms ^- by this digital-domain column FPN correction. Low-voltage low-power serial video interface and noise decoupling on pixel drive voltages contribute to row-temporal-noise reduction to 0.31 e_rms ^-. Both column FPN and row temporal noise are not visible in spite of a low readout noise floor of 2.8 e_rms ^-.     

Fast-switching all-printed organic electrochemical transistors

Symmetric and fast (～5 ms) on-to-off and off-to-on drain current switching characteristics have been obtained in screen printed organic electrochemical transistors (OECTs) including PEDOT:PSS (poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonic acid)) as the active transistor channel material. Improvement of the drain current switching characteristics is made possible by including a carbon conductor layer on top of PEDOT:PSS at the drain electrode that is in direct contact with both the channel and the electrolyte of the OECT. This carbon conductor layer suppresses the effects from a reduction front that is generated in these PEDOT:PSS-based OECTs. In the off-state of these devices this reduction front slowly migrate laterally into the PEDOT:PSS drain electrode, which make off-to-on switching slow. The OECT including carbon electrodes was manufactured using only standard printing process steps and may pave the way for fully integrated organic electronic systems that operate at low voltages for applications such as logic circuits, sensors and active matrix addressed displays.     

A highly linear double balanced Schottky diode S-band mixer

A high-level double balanced SiC Schottky diode mixer in SiC monolithic microwave integrated circuit (MMIC) technology has been designed, processed and characterized. The mixer is a single ended in- and output circuit with coupled transformers as baluns to enable a compact design, resulting in a total area of 2.2/spl times/2.2mm/sup 2/. The mixer has a maximum IIP/sub 3/ of 38dBm and IIP/sub 2/ of 58dBm at 3.3GHz, and a typical P/sub 1 dB/ of 23dBm in the S-band. The minimum conversion loss was 12dBm at 2.4GHz. The high power operation of the mixer shows that SiC MMIC can perform well in high microwave radiation environments.     

Preemption-light multiprocessor scheduling of sporadic tasks with high utilisation bound

Known algorithms capable of scheduling implicit-deadline sporadic tasks over identical processors at up to 100% utilisation invariably involve numerous preemptions and migrations. To the challenge of devising a scheduling scheme with as few preemptions and migrations as possible, for a given guaranteed utilisation bound, we respond with the algorithm NPS-F. It is configurable with a parameter, trading off guaranteed schedulable utilisation (up to 100%) vs preemptions. For any possible configuration, NPS-F introduces fewer preemptions than any other known algorithm matching its utilisation bound.     

Polyhedral perturbations that preserve topological form

The idea, that we are willing to accept variation in an object but that we insist it should retain its original topological form, has powerful intuitive appeal, and the concept appears in many applied fields. Some of the most important of these are tolerancing and metrology, solid modeling, engineering design, finite element analysis, surface reconstruction, computer graphics, path planning in robotics, fairing procedures, image analysis, and medical imaging. In this paper we focus on the field of tolerancing and metrology. The requirement that two objects or sets should have the same topological form requires a precise definition. We specify “same topological form” to mean that there exists a “space homeomorphism” from R³ onto R³ that carries a nominal object S onto another design object. In general, establishing the existence of such space homeomorphisms can be considerably more difficult than demonstrating classical topological equivalence by a homeomorphism. In the special case when the boundary of S is a polyhedral two-sphere in R³, one of the authors has previously given a simple sufficient condition for the existence of a space homeomorphism mapping S onto another design object. This paper presents an analogous sufficient condition for the case when S is a finite polyhedron in R³. The result relies upon a triangulation of the boundary and upon a dependent parameter that specifies the maximum size of permissible perturbations of the vertices of the polyhedron.     

Spin diode based on Fe/MgO double tunnel junction

We demonstrate a spin diode consisting of a semiconductor-free nanoscale Fe/MgO-based double tunnel junction. The device exhibits a near perfect spin-valve effect combined with a strong diode effect. The mechanism consistent with our data is resonant tunneling through discrete states in the middle ferromagnetic layer sandwiched by tunnel barriers of different spin-dependent transparency. The observed magnetoresistance is a record high>1000%, essentially making the structure an on/off spin switch. This, combined with the strong diode effect, approximately 100, demonstrates a new device principle, promising for memory and reprogrammable logic applications.     

The significance of weldment material mis-matching on stress redistribution and creep cracking of high temperature components

A large circumferentially oriented crack was discovered in a weld of a double T-piece in the main steam pipe of a Swedish power plant. The pipe and the weld were manufactured from 0.5Cr0.5Mo0.25V steel. In this paper a nominal creep life assessment and an assessment considering mis-matching are carried out for a defect free component and for a component with a crack. While the nominal prediction of a defect free component indicates a creep life of approximately 2200000 hours, a creep life of 550000 hours is obtained when mis-matching effects and enhanced axial stresses due to system loads are considered. If mis-matching is not taken into account, as opposed to if it is, the estimated incubation plus creep crack growth time is approximately 30–70% longer.