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This paper adopts an M/G/1 retrial queueing system with imperfect coverage and reboot delay. When the system detects an arrival, it will immediately process the arrival. On the other hand, if the arrivals are not detected, the system will get into an abnormal state until it is restarted. Using the supplementary variable approach, the stationary probability generating function for the number of retrial arrivals and performance measures are derived. For illustration purposes and to study the impact of system parameters on performance measures, a real-world case of the data transmission mechanism for renewable energy power plants is presented to perform the optimisation analysis. Optimisation analysis is implemented to determine the optimum service rate to minimise the mean operating cost and the mean time of an arrival spent in the system.

The origin of cancers is associated with etiology as well as therapeutics. Several studies reveal that malignancies in children can originate in utero. However, a diagnostic approach to distinguish between cancers initiated pre- or postnatally is absent. Here we identified a transcriptional factor FEV (fifth Ewing variant) that was expressed in fetal hematopoietic cells and became silent after birth. We characterized that FEV was essential for the self-renewal of hematopoietic stem cells (HSCs). We next found that FEV was expressed in most infant leukemia samples, but seldom in adult samples, in accord with the known prenatal origins of the former. We further determined the majority of pediatric acute lymphoid leukemia (ALL) and acute myeloid leukemia (AML) were FEV positive. Moreover, FEV knockdown markedly impaired the leukemia-propagating ability of leukemic stem cells. We therefore identified FEV is unique to fetal HSCs and stably expressed in leukemic cells of prenatal origin. It may also provide a tractable therapeutic target.

The static friction characteristic was investigated in the case of litchi picker's clamp heads made of PVC plastic, silicone and rubber, carved with textures of circular, sawtooth, plain and grid, when in contact with litchi stalks. An experimental device was developed and used to measure the static coefficient of friction between a flat surface and cylinder. Clamp heads made of rubber were found to have the biggest static coefficient of friction, and clamp heads made of PVC plastic were found to have the smallest static coefficient of friction. Clamp heads carved with circular texture were found to have the biggest static coefficient of friction, and clamp heads carved with grid texture were found to have the smallest static coefficient of friction. And for specimens of different sizes, the bigger the diameter, the bigger the static coefficient of friction. Results suggest that the best clamp heads for a litchi picker are made of rubber, carved with circular texture, and a bigger clamping force is required to pick smaller stalks.

Spiro-FPA, a novel blue emitter, in which two identical anthracene luminophores are linked orthogonally around a spirobifluorene core, has been synthesized and characterized. The introduction of a spiro linkage into the structure of spiro-FPA leads to a reduction in crystallization tendency and an increase in glass transition temperature relative to the monomeric units. In addition, the tetrahedral nature of the carbon atom at the spiro center preserves the optical and electrochemical characteristics of the pristine anthracene units. As demonstrated by AFM measurements, high-quality amorphous films of spiro-FPA with good morphological stability can be prepared by vapor deposition. Organic EL devices constructed using a 1.0-wt % TBP-doped spiro-FPA emitting layer produce bright blue emissions with a high luminescence efficiency of 4.9 cd/A (2.07 lm/W).

This paper deals with a unique and severe stratification phenomena in the pressurizer surge line piping system. The methodology used in the calculation of total stress state includes pressure stresses from internal pressure, global thermal stresses from the constraining of the system by supports, local thermal stresses from hot/cold stratified condition, and transient thermal stresses in the pipe and at structural discontinuities. Special discussion on the interpolation to obtain moment loadings from one state of thermal condition to the next with nonlinear gapped support system is presented. Finally, the thermal cycling associated with operating transients in the surge line system is also addressed.

Probe beam amplification in a Kerr-like medium, e.g. a nematic liquid crystal film via 2-wave mixing is possible if it is stoke shifted relative to the pump beam. We report experiment observation of this effect and contribution from other multi-wave mixing effects.

This paper deals with a unique and severe stratification phenomena in the pressurizer surge line piping system. The methodology used in the calculation of total stress state includes pressure stresses from internal pressure, global thermal stresses from the constraining of the system by supports, local thermal stresses from hot/cold stratified condition, and transient thermal stresses in the pipe and at structural discontinuities. Special discussion on the interpolation to obtain moment loadings from one state of thermal condition to the next with nonlinear gapped support system is presented. Finally, the thermal cycling associated with operating transients in the surge line system is also addressed.

This paper: (1) classifies design constraints of mechanical systems from a multi-disciplinary, concurrent engineering point of view from three orthogonal bases: application, object, and expression, (2) presents some initial developments in extending data models to include design constraints, formally defining entity relationships using first order predicate logic, and modeling assembly related geometry constraints for mechanical systems using predicates. Axioms and atomic formulas of mechanical assemblies are developed. Two frequently used assembly relationships-fit and against—are defined and used to explain the assembly definition axiom of a piston assembly of an engine model. Such a geometry constraint modeling method builds a basis for design change propagation and change management.

We studied the effects of long-term fish oil (FO) dietary supplementation on brain edema, polymorphonuclear neutrophil (PMN) infiltration, and infarct size in a rat stroke model. Rats were given regular rat chow with or without FO supplement (20 of total calories) for 7 weeks. Body weight did not differ between the two groups. In the FO group, an increase in eicosapentaenoic acid and a decrease in arachidonic acid content in hepatic phospholipids were significant in the phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine but not in the phosphoinositol fraction. Platelet activity reflected by serum thromboxane B2levels was reduced in the FO group. Postischemic brain edema and PMN infiltration were not different between the two groups. The infarct volume was significantly greater in the FO group (controls: 96 ±7 mm3, n 49; FO group: 124 ± 6 mm3, n 53; p0.0036). The greater ischemic brain injury in the FO-supplemented animals is probably related to the intraischemic hyperglycemia, which was worse in the FO group than in the control group (controls: 265 ± 19 mg/dl, n 14; FO group: 340 ± 18 mg/dl, n 16; p0.0079).

A wild nontuberizing potato species Solanum brevidensPhil, was transformed with Agrobacterium tume-faciensstrain GV2260 containing chimeric neomycin phosphotransferase and potato proteinase inhibitor II (Pis4) promoter-GUS (uidA) genes on the disarmed plasmid pRT210. Several independent transgenic plantlets were regenerated on kanamycin-containing medium. Analysis of polymerase-chain-reaction products followed by Southern blot hybridization confirmed the presence of uidA genes in three of the transformants. Transgenic plants were tested for methyl jasmonate, sucrose, and wound induction of the pinII-GUS genes at the RNA and protein levels using leaf-petiole cuttings and whole plants. Northern blot analysis showed that the Pis4-uidAtransgene can be induced by methyl jasmonate and sucrose. Methyl jasmonate-induced GUS activity in transgenic plants was up to fifteen times higher than basal levels after 12-h incubation and up to twenty-three times higher than basal levels after 24 h. Wounding of transgenic S. brevidensleaves on whole plants resulted in a substantial induction of GUS activity both locally and systemically.

We present a theoretical study, with reference to experimental results, of transverse self-phase modulation effects in the transmission of a laser beam through a nonlinear thin film. The occurrence of interference rings, intensification or dimming of the on-axis beam intensity, and transverse optical bistability in the presence of a feedback can all be systematically documented in terms of geometrical/optical parameter classifications. These studies provide further insights and useful guides for experimental studies.

We present a detailed theoretical calculation, with experimental verification, of the nonlocal molecular reorientation of the nematic-liquid-crystal director axis induced by a cw Gaussian laser beam. The natures of the torque balance equations and the solutions are significantly different for normally and nonnormally incident laser beams. The nonlocal effects resulting from molecular correlation effects are particularly important for laser spot sizes that are different (smaller or larger) from the sample thickness. Experimental measurements for the transverse dependence of the molecules and the dependence of the Freedericksz threshold as a function of the laser beam sizes are in excellent agreement with theoretical results. We also comment on the effect of these nonlocal effects on transverse optical bistability.

The protein kinase Chk1 is required for cell cycle arrest in response to DNA damage. We have found that the 14-3-3 proteins Rad24 and Rad25 physically interact with Chk1 in fission yeast. Association of Chk1 with 14-3-3 proteins is stimulated in response to DNA damage. DNA damage results in phosphorylation of Chk1 and the 14-3-3 proteins bind preferentially to the phosphorylated form. Genetic analysis has independently implicated both Rad24 and Rad25 in the DNA-damage checkpoint pathway. We suggest that DNA damage-dependent association of phosphorylated Chk1 with 14-3-3 proteins mediates an important step along the DNA-damage checkpoint pathway, perhaps by directing Chk1 to a particular substrate or to a particular location within the cell. An additional role for 14-3-3 proteins in the DNA-damage checkpoint has been suggested based on the observation that human Chk1 can phosphorylate Cdc25C in vitro creating a 14-3-3 binding site. Our results suggest that in fission yeast the interaction between the 14-3-3 proteins and Cdc25 does not require Chk1 function and is unaffected by DNA damage, in sharp contrast to the interaction between the 14-3-3 proteins and Chk1.

We present an analytical treatment of the nonlocal transverse dependence of the molecular reorientation induced by a Gaussian laser beam in a nematic liquid crystal. In the limit of small laser beam width compared to the film thickness, the induced molecular reorientation's transverse dependence exhibits broadening effect. These results are significant in opto-optical switching and self-phase modulation bistability.

Two plant species, potato (Solanum tuberosumcv. Superior) and a nontuberizing potato species (Solanum brevidens), were tested for methyl jasmonate induction of the potato cathepsin D inhibitor at the RNA level using a leaf-petiole cutting system. Both species had previously shown accumulation of cathepsin D inhibitor transcripts in leaves in response to wounding. Methyl jasmonate, a hormone-like, lipidderived molecule, is considered to be a secondary messenger in the wound-signal transduction pathway and is a potent inducer of proteinase inhibitor II. A dose-response test was performed for methyl jasmonate induction of cathepsin D inhibitor in the leaves of leaf-petiole cuttings. Transcript induction levels were directly related to the concentration of methyl jasmonate. Cathepsin D inhibitor transcripts could be detected in the Solanumspecies after only 6 h of methyl jasmonate treatment. Immunoblot analysis showed cathepsin D inhibitor proteins accumulated in «Superior» leaves after methyl jasmonate treatment.

The nucleotide sequences of a portion of the large-subunit mitochondrial rRNA gene of Pneumocystis carinii derived from 12 patients were examined. Five sequences were found to be identical to the prototype sequence reported by Sinclair et al. (K. Sinclair, A. E. Wakefield, S. Banerji, and J. M. Hopkin, Mol. Biochem. Parasitol. 45:183-184, 1991). Six sequences differed from the prototype sequence at one to three positions. The remaining sequence was markedly different from the prototype sequence and appeared to be a hybrid of the human and rat P. carinii sequences. The results of this study indicate the existence of multiple P. carinii strains infecting humans and suggest that coinfections of animal and human P. carinii strains in the same host are possible.

We present a detailed theoretical analysis of degenerate four-wave mixing by a laser-induced thermal grating in a nematic liquid-crystal film. In particular, we show that the coupling of the (strong) pump beam to the first-order diffracted beam can give rise to substantial amplification of a (weak) probe beam. Experimental verification of this effect with a CO_2 laser beam is also made. A probe-beam gain of greater than 20 can easily be observed in a 120-μm film with a pump intensity of the order of a few watts per square centimeter.

Ischemic damage to the prefrontal, motor, and somatosensory cortex induces alterations in the receptor systems of the caudate putamen and some subcortical brain regions. These alterations may represent an attempt of various neuronal systems to compensate for the reduction in innervation caused by the cortical infarction. Assessment of the receptor changes induced by cortical infarction define neuropharmacologic correlates of cortical damage, indicate possible neurotransmitters associated with neuroanatomically defined subcortical pathways, and suggest possible pharmacologic interventions to counteract the consequences of stroke. Bilateral cortical infarction, induced by ligation of both middle cerebral arteries and temporary occlusion of both common carotid arteries, was investigated in the rat. The infarction resulted in dramatic alterations in subcortical receptor populations us determined by autoradiography. Sodium-dependent, high-affinity, choline-uptake (SDHACU) sites and D₁-dopamine receptors in the caudate putamen were unaffected by the infarction, whereas muscarinic and glutamate receptors were increased and D₂ receptors were decreased in this structure. A reduction in SDHACU sites caused by the lesion was found in regions including the medial septum, vertical nucleus of the diagonal band, thalamus, nucleus basalis magnocellularis, and basolateral amygdala. M₁ receptors were increased in the basolateral and central amygdaloid nuclei whereas non-M₁ receptors were increased in the basolateral and central amygdaloid nuclei, but were diminished in the medial septum, vertical nucleus of the diagonal band, thalamus, and nucleus basalis magnocellularis. No significant alterations in muscarinic binding were observed in the various laminae of the hippocampus and dentate gyrus. Copyright 1994, 1999 Academic Press

Using low-power cw lasers in conjunction with the symmetric and asymmetric nonlinear transverse self-phase modulation imparted by a nematic liquid-crystal film, we have demonstrated two forms of transverse intensity-switching and power-limiting operations. Applications to high-power nanosecond laser are also feasible.

Based on experimental analogue MOS switches, the Letter reports a new observation of the charge injection component due to channel charges in weak inversion. As identified by the mixed-mode circuit and device simulations, this new component can contribute comparably to the switch-induced error voltage on a switched capacitor.

A high-power-density and high-efficiency molecular-beam-epitaxy-grown atomic-planar-doped AlGaAs/InGaAs quantum-well power high-electron-mobility transistor (HEMT) was developed for low-voltage medium-power wireless communication applications. The HEMT exhibited a maximum drain current of 420 mA/mm and a maximum transconductance of 275 mS/mm. A two-dimensional electron gas with a high sheet charge density and a high electron mobility in the InGaAs quantum well contributed to the high current density and high transconductance of the HEMT and enhanced the device power performance at low operating voltage. An output power density of 177 mW/mm and a power-added efficiency of 61% were achieved by the 2 mm HEMT at a drain voltage of 2.4 V and a frequency of 900 MHz. At 2.1 V drain voltage and 2.4 GHz frequency, the device demonstrated an output power of 24.4 dBm and a power-added efficiency of 57.4%. An adjacent channel leakage power of -55 dBc was attained for the 1.9-GHz ?/4-shifted quadrature phase shift keying modulation when the output power was 22.2 dBm and the drain voltage was 2.4 V.