cssi/SciSciGPT-SciSciNet huggingface dataset:
Condition assessment-An industry perspective

Worldwide, the number of aged (>30 years service) fossil plants is already significant and is increasing. These units still comprise a substantial portion of electric generation capacity and are likely to remain in service for 15 or more years as new generation finally replaces these assets. Critically, these units must still perform safely and reliably during their “golden years” when most would have been expected to have been retired. The good news is that the level of technical understanding of component damage mechanisms, their root causes, and the corrective actions for root cause is far better today than when these plants first entered service. This technical knowledge base now provides the means to operate these aged units safely and reliably well past the nominal design life. The keys, however, are to use the knowledge to avoid or minimize damage accumulation and to use advanced inspection and monitoring tools to detect any damage at earlier stages. This paper will review the recommended processes now available to allow fossil plants to age gracefully and avoid risks of high failure rates and low reliability.
Alfalfa Yield Component Responses to Seeding Rate Several Years after Establishment

Little information is available regarding the relationships of alfalfa (Medicago sativa L.) forage yield with yield components in seed-established stands grown under dryland conditions. Field experiments that included two cultivars and 15 seeding rates ranging from 2.2 to 33.6 kg pure live seed ha #751 were established in 1985 at Brookings and Highmore, SD. The objective was to determine seeding rate effects on components of alfalfa forage yield and on plant morphology several years alter establishment (...)
Phase II study of prolonged oral etoposide in combination with intravenous cisplatin in advanced non-small cell lung cancer

The objectives of the study were to evaluate the combination of cisplatin and prolonged oral etoposide for response rate, survival, and toxicity. The treatment regimen consisted of etoposide (50 mg/m2/day) p.o. for 21 consecutive days and cisplatin (100 mg/m2) i.v. on day 1 every 28 days for up to six courses. Patients with Stage IIIB or IV non-small cell lung cancer who had not received prior chemotherapy and had an ECOG performance status of 0-2 were eligible if they had normal bone marrow, liver and renal functions. Patients were followed weekly for toxicity including complete blood counts. The total number of patients entered in the study was 60, of whom 56 were male and four female, 40 white and 20 African Americans. Median age was 64 years (range, 39-77). Performance status 0, 1, and 2 was present in five, 39, and 16 patients, respectively. Fourteen patients had Stage IIIB and 46 Stage IV disease. A total of 142 treatment courses were administered (median 2, range 1-6). Three patients had a complete response and 19 patients had a partial response for an objective response rate of 37% (95% confidence interval, 31-43%). Median survival was 5 months (range, 1-39+). Neutropenia was the major toxicity with Grade 4 occurring in 25 patients after the first course. The following percent of patients experienced severe or life-threatening hematologic toxicity (Grade 3 and 4 combined) over all courses: leukopenia, 73%; neutropenia, 73%; anemia, 42%; and thrombocytopenia, 37%. Three patients died of neutropenic sepsis.(ABSTRACT TRUNCATED AT 250 WORDS)
The effect of chronic digitalization on pump function in systolic heart failure.

Background: Short- and intermediate-term use of cardiac glycosides promotes inotropy and improves the ejection fraction in systolic heart failure. Aim: To determine whether chronic digitalization alters left ventricular function and performance. Methods: Eighty patients with mild-to-moderate systolic heart failure (baseline ejection fraction ≤ 45%) participated from our institution in a multi-center, chronic, randomized, double-blind study of digitalis vs. placebo. Of the 40 survivors, 38 (20 allocated to the digitalis arm and 18 to the placebo arm) were evaluated at the end of follow-up (mean, 48.4 months). Left ventricular systolic function was assessed by both nuclear ventriculography and echocardiography. The ejection fraction was measured scintigraphically, while the ventricular volumes were computed echocardiographically. Results: The groups did not differ, at baseline or end-of-study, with respect to the ejection fraction and the loading conditions (arterial pressure, ventricular volumes and heart rate) by either intention-to-treat or actual-treatment-received analysis. Over the course of the trial, the digitalis arm exhibited no significant increase in the use of diuretics (18%, P - 0.33), in distinction from the placebo group (78%, P - 0.004), and a longer stay on study drug among those patients who withdrew from double-blind treatment (28.6 vs. 11.4 months, P - 0.01). Conclusion: Following chronic use of digitalis for mild-to-moderate heart failure, cross-sectional comparison with a control group from the same inception cohort showed no appreciable difference in systolic function or performance. Thus, the suggested clinical benefit cannot be explained by an inotropic effect.
The effect of exteroceptive pup stimuli on the responsiveness of prolactin release mechanisms to suckling stimuli in the lactating rat.

In the lactating rat, the neural stimulus of suckling not only acutely releases PRL but also maintains the responsiveness of PRL regulatory mechanisms to subsequent nursing stimuli. Beginning near midlactation exteroceptive pup stimuli (ECS) can acutely release PRL. We have examined the capacity of this signal also to maintain the responsiveness of PRL release mechanisms to subsequent suckling stimuli. On day 14 postpartum lactating rats were either isolated from their young or exposed to ECS (without suckling) for approximately 24 h. When both groups were later nursed, plasma PRL of mothers earlier exposed to ECS rose significantly higher than that of subjects previously isolated from their young. Suckling produced a significant depletion in pituitary PRL and GH concentrations of ECS-exposed mothers; it did not produce a similar depletion in the pituitaries of the previously isolated group. When the pups were returned for suckling, ECS-exposed mothers began to nurse their pups substantially faster than d...
Effect of supercoiling on formation of protein mediated DNA loops

DNA loop formation is one of several mechanisms used by organisms to regulate genes. The free energy of forming a loop is an important factor in determining whether the associated gene is switched on or off. In this paper we use an elastic rod model of DNA to determine the free energy of forming short (50-100 basepair), protein mediated DNA loops. Superhelical stress in the DNA of living cells is a critical factor determining the energetics of loop formation, and we explicitly account for it in our calculations. The repressor protein itself is regarded as a rigid coupler; its geometry enters the problem through the boundary conditions it applies on the DNA. We show that a theory with these ingredients is sufficient to explain certain features observed in modulation of in vivo gene activity as a function of the distance between operator sites for the lac repressor. We also use our theory to make quantitative predictions for the dependence of looping on superhelical stress, which may be testable both in vivo and in single-molecule experiments such as the tethered particle assay and the magnetic bead assay.
EXACT ANALYSIS OF AN INTERACTING BOSE GAS. I. THE GENERAL SOLUTION AND THE GROUND STATE

A gas of one-dimensional Bose particles interacting via a repulsive delta-function potential has been solved exactly. All the eigenfunctions can be found explicitly and the energies are given by the solutions of a transcendental equation. The problem has one nontrivial coupling constant, γ. When γ is small, Bogoliubov’s perturbation theory is seen to be valid. In this paper, we explicitly calculate the ground-state energy as a function of γ and show that it is analytic for all γ, except γ=0. In Part II, we discuss the excitation spectrum and show that it is most convenient to regard it as a double spectrum—not one as is ordinarily supposed.
Autonomic regulation of cardiac function during sleep in patients with irritable bowel syndrome

Abstract OBJECTIVE: Several studies have provided evidence of abnormal autonomic activity in irritable bowel syndrome (IBS), suggesting that abnormal central nervous system–autonomic nervous system arousal mechanisms may be part of its pathophysiology. The goal was to investigate cardiac sympatho-vagal balance during waking and the different stages of sleep using heart rate variability analysis in IBS patients compared to healthy controls. METHODS: A total of 15 IBS patients (13 female, two male, mean age 34.9 ± 2.1 yr) and 15 controls (13 female, two male, mean age 36.2 ± 2.3 yr) were studied during 1 h of pre-sleep quiet waking and during seven-hours of sleep. Polysomnography was used for the determination of state of consciousness. Electrocardiography provided the beat-to-beat intervals, which were then subjected to spectral analysis for determination of the percentage of energy in the low and high frequency bands, respectively. The low frequency/high frequency band ratio was also calculated. For each subject, heart rate variability analysis was performed using 15-min segments of waking, non–rapid eye movement sleep, and rapid eye movement sleep. RESULTS: The low frequency band power was significantly greater in IBS patients during waking. No group differences were found in high frequency band power during any state. The low frequency to high frequency band ratio was significantly greater in IBS patients during rapid eye movement sleep. CONCLUSIONS: IBS patients have greater sympathetic activity during waking and greater overall sympathetic dominance during rapid eye movement sleep. These results support the presence of autonomic abnormalities in patients with IBS. The possibility is discussed that sympathetic dominance during rapid eye movement sleep may play a role in sensitizing the gut to waking stimulation.
Expanded Fermi Solution to estimate health risks or benefits from interacting factors

Food related health risk/benefit factors might be additive or multiplicative, but some can be interrelated in ways that are neither or both. Since there is always inherent uncertainty concerning the magnitude of risk/benefit factors their contribution is better represented by a probable range than a single numerical value. With the Expanded Fermi Solution method, random values of the factors are generated within their respective ranges and used to calculate the combined risk or benefit based on the chosen mathematical model. In the case of additive or multiplicative independent factors, the combined risks/benefits so calculated have approximately normal or lognormal distribution, respectively, as anticipated from the Central Limit Theorem. The distribution's mode, i.e., the most frequent value, is considered the risk's best estimate. In interactive factors, the emergence of a specific parametric distribution is not guaranteed, but the histogram of the randomly generated combined risks or benefits can be used to identify the best estimate. This is demonstrated with three abstract interactive risk/benefit models of increasing number of parameters and complexity, whose calculation has been automated and posted on the Internet as freely downloadable interactive Wolfram Demonstration. Also given is a hypothetical but realistic example of dose–response based microbial risk assessment where uncertain bacterial growth parameters are involved, which can be implemented with a new Wolfram Demonstration. The methodology and software allow rapid examination of numerous combinations of interactive factors and evaluation of their potential effect on a food's or supplement's risk or benefit.
Secretion of cytokines and growth factors as a general cause of constitutive NFκB activation in cancer

The constitutive activation of nuclear factor kappaB (NFkappaB) helps a variety of tumors to resist apoptosis and desensitizes them to chemotherapy, but the causes are still largely unknown. We have analysed this phenomenon in eight mutant cell lines derived from human 293 cells, selected for NFkappaB-dependent expression of a marker gene, and also in seven tumor-derived cell lines. Conditioned media from all of these cells stimulated the activation of NFkappaB (up to 30-fold) in indicator cells carrying an NFkappaB-responsive reporter. Therefore, secretion of extracellular factors as the cause of constitutive activation seems to be general. The mRNAs encoding several different cytokines and growth factors were greatly overexpressed in the tumor and mutant cells. The pattern of overexpression was distinct in each cell line, indicating that the phenomenon is complex. Two secreted factors whose roles in the constitutive activation of NFkappaB are not well defined were investigated further as pure proteins: transforming growth factor beta2 (TGFbeta2) and fibroblast growth factor 5 (FGF5) were both highly expressed in some mutant clones and tumor cell lines, each activated NFkappaB alone, and the combination was synergistic. Our data indicate that a group of different factors, expressed at abnormally high levels, can contribute singly and synergistically to the constitutive activation of NFkappaB in all of the mutant and tumor cell lines we studied. Since several NFkappaB target genes encode secreted proteins that induce NFkappaB, autocrine loops are likely to be ubiquitously important in the constitutive activation of NFkappaB in cancer. We provide the first evidence of the general, complex, and synergistic activation of NFkappaB in tumor and mutant cell lines through the action of secreted factors and suggest that the same explanation is likely for the constitutive activation of NFkappaB in cancers.
Experimental reorganization of the cerebellar cortex. III. Regeneration of the external germinal layer and granule cell ectopia

The heads of Long-Evans hooded rats were irradiated daily from day 3, 4 or 6 onward with schedules of low-level x-ray which differentially delayed the regeneration of the subtotally eradicated external germinal layer or prevented its regeneration altogether. Most schedules that permitted regeneration led to the arrest of many granule cells in the molecular layer where they formed an ectopic zone. The dendrites of ectopic granule cells had synapses with mossy fibers located in their vicinity in the molecular layer. The position of the ectopic zone varied in different lobules depending on several factors: the time when regeneration began, the estimated date of descent of granule cells, regional differences in cortical maturation and in the estimated upward growth rate of mossy fibers. Within the same lobule, the longer regeneration was delayed the higher in the molecular layer the differentiating and descending granule cells were captured by the apparently autonomously ascending mossy fibers. If regeneration started early and allowed the descent of granule cells into the granular layer (early irradiation) or if regeneration of granule cells was prevented altogether (late irradiation) an ectopic zone was not formed. The technique was used for estimating the normal growth pattern of mossy fibers in the different lobules.
Polymerization of acrylamide using the hydrogen peroxide–hydroxylamine couple†

The large heat of polymerization for acrylamide makes the measurement of conversion by temperature rise in an adiabatic system quite convenient. The initial monomer concentration in the reaction medium ranged from 0.2 to 0.8 mol/kg while the concentration of the two initiator components was varied from 1 to 100 mmol/kg. The adiabatic reactor was an aluminum beaker with a thin internal organic liner. The reactor was insulated and shielded. Approximate reactor charge was 200g. Iron has a pronounced accelerating effect on the rate. The predominant reaction appears to be the iron-catalyzed decomposition of hydrogen peroxide in the presence of small amounts of hydroxylamine hydrochloride. At hydroxylamine to peroxide ratios greater than about 1:2, there seems to be no further benefit from hydroxylamine additions. The activation energy is lowered by the addition of iron decreasing from 18.7 kcal/mol with no added iron to 4.5 kcal/mol when the system contains 1 ppm iron.
It takes all kinds to make a brain.

Variation in neuronal properties is often thought of as noise that interferes with information processing. A study now suggests that neuronal diversity may actually improve the coding capacity of neural ensembles.
Crystal structure and a twisted β-sheet conformation of the tripeptide L-leucyl-L-leucyl-L-leucine monohydrate trimethanol solvate: Conformation analysis of tripeptides

In order to test the helical preference of short oligo-L-leucines, we crystallized the tripeptide L-leucyl-L.-leucyl-L-leucine (LLL) and carried out x-ray diffraction studies of it (L-leucyl-L-leucyl-Lleucine)2. 3CH3OH. H2O, (C39H84N6O12). Crystallized in the monoclinic system, space group P21, cell parameters: a = 12.031(2), b = 15.578(3), c = 14.087(2) A, α = 90°, β = 97.29(1)°, γ = 90°, V = 2618.6 A3. MW = 829.1, Dc = 1.051 gcm−3. R index of 0.057 for 4213 reflections (λcukα = 1.5418 A) > 2σ. LLL takes tip the β-sheet rather than a helical conformation in the crystalline stale. The three methanol molecules and the water molecule that constitute the solvent of crystallization form a network of hydrogen bonds to the LLL molecules and to one another. It is rather remarkable that though A and L have stronger helical preferences than G, neither AAA nor LLL form the crystalline helix but GAL does, indicating that the helical preferences depend on the sequence context. The residue L2 in molecule A and the residues L1 and L3 of molecule B do not show the preferred conformation for forming helices. Further, very remarkably. LLL exhibits a unique super secondary feature of the protein folding topology, namely the twisted β-sheet. Where as most short peptides show only the classical p-sheet conformation. Thai even the tripeptide LLL is able to exhibit the twisted β-sheet conformation, and with the correct left-handed twist this suggests that even very short peptide segments possess the ability to assume several of the characteristic topological features exhibited by proteins. An extensive review of tripeptide conformations has been carried out and some results of this study have been included here. © 1995 John Wiley & Sons, Inc.
Effect of time of day on the relationship between mood state, anaerobic power, and capacity.

Mood state was estimated in six men using the Profile of Mood States questionnaire, with a “right now” directional set prior to performance of a modified Wingate power test, once at 03.00 hr., 09.00 hr., 15.00 hr., and 21.00 hr., on different days. Anaerobic power was measured as peak power output in 5 sec., and anaerobic capacity was measured as total external work performed during the 30-sec. test. Intraindividual difference scores were calculated as a subject's score minus his mean over the four tests. Multiple regression analyses showed that time of day and the Profile of Mood States fatigue score accounted for 51% of the variance in peak power and 62% of the variance in anaerobic capacity. However, the relationships between fatigue and subsequent anaerobic power and capacity reached statistical significance only at 21.00 hr. These results suggest that intraindividual differences in the mood state are related to subsequent performance. Greater than usual levels of fatigue are associated with reduced p...
Computer Aided Interfacial Measurements

The sessile drop profile method was combined with X-ray radiography to develop a precise method to measure interfacial tensions and contact angles of liquid metals at high temperatures and in a variety of atmospheres. An accurate method of digital image processing was developed to capture, enhance and determine the coordinates of the X-ray shadow image of the droplet. Laplace's equation was then solved numerically to allow a non-subjective determination of interfacial tension and contact angles.Examples of the determination of the interfacial tension of mercury in argon, of liquid iron at 1 550°C under various CO/CO2 gas mixtures, of iron carbon alloys and of liquid iron in contact with a lime-alumina-silica slag at 1 550°C, are given.
Isolated dislocation of the trapezoid bone.

The authors present a case of a patient with an isolated dislocation of'the trapezoid bone, report on the methods of treatment, and discuss their conclusions.
The Effect of Thermal Resistance for Dropwise Condensation on Hydrophobic Micro-Pillared Structures

Superhydrophobic/hydrophobic surfaces, developed to promote dropwise condensation, can be produced by modifying the surface chemically with low surface energy films, and/or structurally by fabricating micro-textured surfaces. Some research has reported the increased thermal resistance from the added chemical layer and its effect on condensation heat transfer. A critical question of interest is the thermal resistance due to micro-pillared structures and their influence on droplet growth during condensation as compared to smooth or non-textured surfaces. Though idealized, this paper presents a theoretical and computational model for evaluating and quantifying the effects of the pillared structures thermal resistance, as well as the continuum versus non-continuum mechanisms affecting droplet growth during dropwise condensation. The model is used to compare different micro-pillared surfaces, cited in the literature, and to predict which micro-pillar dimensions contribute to slower condensate growth despite the higher contact angle advantage during dropwise condensation.© 2012 ASME
EM radiation estimation using an automatic probe position recording system coupled to hand scanning

Compared to scanning by hand, traditional robotic scanning to measure or to inject EM near field has advantages and disadvantages. It can scan large area with excellent resolution. However, it is difficult to program the experience of engineers into the robotic system for selecting scan areas, and complex shaped objects are nearly impossible to scan automatically. A CMM (Coordinate Measuring Machine) arm based probe recording system has been developed to add position recording to hand scanning. Applications of the system include documentation, visualization of the field and current distribution.
Origin of asteroid rotation rates in catastrophic impacts

The rotation rates of asteroids, which are deduced from periodic fluctuations in their brightnesses, are controlled by mutual collisions. The link between asteroid spin and collision history is usually made with reference to impact experiments on centimetre-scale targets, where material strength governs the impact response. Recent work, however, indicates that for objects of the size of most observed asteroids (> or = 1 km in diameter), gravity rather than intrinsic strength controls the dynamic response to collisions. Here we explore this idea by modelling the effect of impacts on large gravitating bodies. We find that the fraction of a projectile's angular momentum that is retained by a target asteroid is both lower and more variable than expected from laboratory experiments, with spin evolution being dominated by 'catastrophic' collisions that eject approximately 50 per cent of the target's mass. The remnant of an initially non-rotating silicate asteroid that suffers such a collision rotates at a rate of approximately 2.9 per day, which is close to the observed mean asteroid rotation rate of approximately 2.5 d-1. Moreover, our calculations suggest that the observed trend in the mean spin frequency for different classes of asteroids (2.2 d-1 for C-type asteroids, 2.5 d-1 for S-type, and 4.0 d-1 for M-type) is due to increasing mean density, rather than increasing material strength.
Throwing out the baby.

In this issue of Blood , Salomao and colleagues reveal the novel mechanism of aberrant protein sorting during enucleation, resulting in additional membrane protein deficiencies in hereditary elliptocytosis and spherocytosis.[1][1] Whereas red cells of all birds, fish, reptiles, and amphibians
A Protocol for Ecosystem Management

Ecosystem science deals empirically with processes that drive biophysical attributes of large landscapes. Ecosystem management should use ecosystem science to facilitate sustained access to ecosystem goods and services (sensu Lubchenco et al. 1991) that humans need or value highly, but polemics about ecosystem management threaten its usefulness and a unified definition and protocol for the concept has proven elusive. In recent workshops and papers about ecosystem management (e.g., Christensen et al. 1996), we have observed three recurring themes: (1) concurrent evaluation of human actions on availability or quality of multiple biological, social, and ecological resources or values should occur at some relevant landscape scale, (2) multidisciplinary, "sound" science should form the information base from which alternative management actions are derived, and (3) "uncertainty" or "risk" analysis should guide selection of management actions to sustain ecosystem function. Taken individually, these themes are not new. Federal land managers have embraced a multiple-use concept since the 1960s, if not earlier. Reliance on multidisciplinary collaborations is a fundamental feature of contemporary ecosystem science (e.g., the LongTerm Ecological Research Program of the National Science Foundation, Franklin et al. 1990). Risk analysis is commonly used in many aspects of natural resource management (e.g., western USA wildfire management). Why, then, is the concept of adaptive ecosystem management so controversial? We believe that the basic three themes rarely are integrated and applied in a regional ecosystem context due to the lack of a unified protocol for implementation of these themes at a landscape scale. We examine herein the three themes that we think underpin the concept of ecosystem management. We then offer a general protocol that links science and public process to multiple resource management objectives in an ecosystem context. Our model is based upon: (1) our belief that shared environmental and social goals, relevant science, and an informed public are requisite for sustaining regional ecosystem processes that provide essential environmental goods and services (e.g., food, fiber, clean water, and air), (2) our belief that the management process must be iterative in order to allow the integration new knowledge and changing societal goals, and (3) our experience in providing ecosystem science as underpinning for management actions that attempt to sustain the pristine attributes of the Flathead Lake catchment, a 22241-km2 montane ecosystem in northwestern Montana, USA, and southeastern British Columbia, Canada.
Commensurability in one-dimensional lattices at finite temperature

The theory of commensurability transitions in one-dimensional atomic chains has been applied to charge density waves, mercury chain compounds, superionic conductors, etc. Previous numerical and analytical results on a model with chains of atoms with nearest neighbor interactions and periodic external potentials have dealt mainly with equilibrium and dynamical properties atT = 0 K. These studies are extended to nonzero temperatures. It is found that the reversible work per particle to slide the chain vanishes in the thermodynamic limit for any nonzero temperature. The mathematical pathologies associated with the commensurability transition atT= 0 (i.e., the “devil's stair”) are absent at finite temperature; only thermodynamic evidence of low-order Commensurability transitions remains.
Oviposition behavior of the littoral rotifer Euchlanis dilatata

Several components of egg-laying behavior in 3 clones of E. dilatata were investigated. Using nearest-neighbor analyses it was shown that individual animals lay their eggs randomly within culture dishes in the absence of an artificial substrate while eggs laid in the presence of a substrate are clumped in 2 of the 3 clones studied. Animals preferentially oviposited on artificial substrates containing eggs when given a choice between artificial substrates with and without eggs of conspecifics. When given a choice of natural substrates, animals consistently laid more eggs on the plant species from which they were collected. This preference persisted for 2 generations after animals had been removed from plants. In addition, observations of neonate hatching behavior demonstrated that neonates often spend relatively long times in the immediate vicinity of hatching.
Behavior of the Si/SiO2 interface observed by Fowler-Nordheim tunneling

Thin‐oxide (40–50 A) metal oxide semiconductor (MOS) structures are shown to exhibit, prior to large levels of electron tunnel injection, the near‐ideal behavior predicted for a uniform trapezoidal barrier with thick‐oxide properties. The oscillatory field dependence due to electron‐wave interference at the Si/SiO2 interface indicates an abrupt, one‐monolayer barrier transition (∼2.5 A) consistent with earlier work. After tunnel injection of 1017 –5×1018 electrons/cm2, the barrier undergoes significant degradation leading to enhanced tunneling conductance, with reproducible behavior observed among different samples. This effect is consistent with the generation of positive states in the region of the oxide near the Si/SiO2 interface (<20 A), where the tunneling electrons emerge into the oxide conduction band. Densities of positive‐charge and interface‐state buildup are also observed from capacitance‐voltage (C‐V) measurements and are found to be consistent with the observed tunneling dependence on positiv...
Expression and purification of E. coli BirA biotin ligase for in vitro biotinylation

The extremely tight binding between biotin and avidin or streptavidin makes labeling proteins with biotin a useful tool for many applications. BirA is the Escherichia coli biotin ligase that site-specifically biotinylates a lysine side chain within a 15-amino acid acceptor peptide (also known as Avi-tag). As a complementary approach to in vivo biotinylation of Avi-tag-bearing proteins, we developed a protocol for producing recombinant BirA ligase for in vitro biotinylation. The target protein was expressed as both thioredoxin and MBP fusions, and was released from the corresponding fusion by TEV protease. The liberated ligase was separated from its carrier using HisTrap HP column. We obtained 24.7 and 27.6 mg BirA ligase per liter of culture from thioredoxin and MBP fusion constructs, respectively. The recombinant enzyme was shown to be highly active in catalyzing in vitro biotinylation. The described protocol provides an effective means for making BirA ligase that can be used for biotinylation of different Avi-tag-bearing substrates.
A linear-time algorithm for optimal multi-channel access in Cognitive Radio Networks

Cognitive Radio Networks (CRNs) aim to maximize the utilization of existing wireless channels by allowing secondary users (SUs) to transmit when licensed primary users (PUs) are not using the same channels. An SU monitors the CRN channels, sensing PU presence to avoid interference and estimating the link quality before transmitting. It stops when one or more available channels with satisfactory link quality are found. Algorithms for making the optimal decision regarding when to stop exploring the channels and start transmitting are expensive in terms of time and space, which are both scarce in hardware-constrained SUs, such as mobile devices. In this paper, we propose a low-complexity algorithm, which utilizes link quality and PU-activity statistics of the CRN channels to pre-compute a set of decision thresholds that will aid the channel exploration phase in maximizing SU-throughput. Our algorithm takes quadratic time and space for offline computations and linear time and space for online processing, which makes it very suitable for space and energy constrained mobile SUs. Our extensive simulation study and analytical model matching the simulation results demonstrate our solution's validity by showing the closeness of throughput and delay performances with the optimum solution as well as solutions by the well-known backward induction method, which often runs in exponential time for offline computations.
New technique for levitating solid particles using a proton beam

A new technique for levitating solid particles inside a vacuum chamber is developed using a proton beam. This new technique differs from the classical laser-levitation technique invented by Ashkin in that it does not heat up light-absorbing levitated particles to vaporization. This unique property of the method will make it possible to levitate real interplanetary dust particles in a vacuum chamber and study their spin-up dynamics in a ground-based laboratory. It is found that a flux of protons from a proton gun of ~1015 cm–2 sec–1 is needed to levitate a 10-mm particle. Confinement of the levitated particle can be achieved by a Z or θ pinch to create a gravity well, or by making the beam profile doughnut in shape.
The evolution of β2-agonists

Beta-agonists have been widely used in the treatment of asthma for many years Although concerns have been expressed over their safety based largely upon epidemics of increased mortality in asthmatics associated with high doses of isoprenaline in the 1960s and fenoterol in the 1970s and 1980s, the specific beta2-agonists are vital drugs in asthma management. The short-acting beta2-agonists have an important prophylactic role in the prevention of exercise-induced bronchoconstriction, and are essential in the emergency treatment of severe asthma. However, little if any benefit seems to be derived from regular use of short-acting beta2-agonists and regular or frequent use can increase the severity of the condition. The development of beta2-agonists with long-acting properties, such as salmeterol and formoterol, has provided advantages over short-acting beta-agonists, such as prolonged bronchodilation, reduced day- and night-time symptoms and improved quality of sleep, and has reduced the requirement for short-acting beta2-agonists as relief medication. Both drugs are well tolerated and, when added to inhaled corticosteroids, produce greater mprovement in lung function than increased steroid dose alone. Because of its rapid onset of action, formoterol also has the potential to be used for as-needed bronchodilator therapy in asthma.
ATF-4 and vascular injury: integration of growth factor signaling and the cellular stress response

See related article, pages 378–387 Smooth muscle proliferation and neointimal formation are characteristic features of vascular lesions that develop after vascular injury and contribute to the development of occlusive vascular lesions after percutaneous coronary interventions and in transplant vasculopathy. The traditional model for the development of these vascular lesions has postulated that a complex interplay among locally released growth factors and cytokines, circulating platelets and inflammatory cells, local smooth muscle and endothelial cells, and perhaps circulating precursor cells involving multiple cellular processes such as adhesion, proliferation, migration, and apoptosis is orchestrated at many levels, resulting in vascular stenosis. The temporal and spatial complexity of the overall process and the diverse contributions of various components have provided many opportunities for study, but identifying and linking the various critical steps in the development of occlusive vascular lesions has remained challenging. Although numerous studies examining roles of vascular signaling pathways and vascular transcription factors have been published, a clear picture of how signaling and transcription are intertwined remains elusive. In this issue of Circulation Research , Malabanan et al present a comprehensive series of experiments linking the transcription factor activating transcription factor (ATF)-4 to intimal thickening after injury and identify both upstream and downstream associated growth factor pathways, thereby providing additional insight into the orchestrated activation of transcriptional and signaling pathways in vascular disease.1 The authors initially identified ATF-4 as a potential regulator of neointimal formation through a microarray screen for genes induced in smooth muscle cells (SMCs) by fibroblast growth factor (FGF)-2. FGF-2 has been identified previously as a major smooth muscle mitogen and has been implicated in the pathogenesis of atherosclerosis and restenosis after angioplasty.2–4 FGF-2 is normally stored and rapidly secreted after injury3 and functions in both an autocrine and paracrine fashion. To confirm the microarray …
Design and process considerations for a tunneling tip accelerometer

In this paper, we discuss the fabrication and initial testing of a bulk micromachined single axis accelerometer. The accelerometer is designed to have a full scale range of and a sensitivity of . Three distinctly different dice are fabricated during the process and are subsequently assembled using an alloy bonding technique. Electrical contacts are made between layers during the bonding operation. The accelerometer is controlled by electrostatic force plates above and below the proof mass. The lower electrode has a dual role. In operation, it provides a necessary control electrode. When not in operation, it is used to immobilize the proof mass.
A Functional-Level Test Generation Methodology Using Two-Level Representations

This paper proposes the use of a functional-level testing methodology based on the generation of test vectors from the functional descriptions of combinational circuits under test. The approach that is adopted involves the generation of a two-level AND-OR, or OR-AND implementation from a circuit's functional description, the generation of test vectors by way of a PODEM based algorithm for the two-level implementation, and the application of the generated tests on a specific implementation(s) of the circuit under test. This approach is experimentally evaluated on various combinational circuits, and is shown to be successful in achieving very high fault-coverages without relying on implementation details of the circuits that are tested.
Spatial variation in dimethylsulfoniopropionate (DMSP) production in Ulva lactuca (Chlorophyta) from the Northeast Pacific

Although dimethylsulfoniopropionate (DMSP) has a variety of functions in marine macroalgae including that of a cryoprotectant, an osmolyte, a way to remove excess sulfur and energy, an antioxidant, and an allelopathic precursor, the latter two functions are believed to be the most important in Ulva lactuca L. (=U. fenestrata) in intertidal populations on the coast of Washington state, USA. The present study found significant variation in DMSP concentrations among U. lactuca collected in May 2005 from six sites ranging from 47°54.45′N (Possession Point, Whidbey Island, WA, USA) to 48°30.55′N (Shannon Point Beach, Anacortes, WA, USA), and also among individuals within sites, and among tissues (basal tissues near the holdfast, middle of the blades, and tips). Concentrations ranged from 37 to 224 μmol g−1 fresh mass (FM). In several 10-day experiments between July 2001 and August 2004 with U. lactuca collected from several places on the coast of Washington, the effects of nutrient level (DIN), light intensity and wavelength, and grazing by the herbivorous gastropod Lacuna vincta, were examined. None of these manipulations resulted in DMSP concentrations that differed significantly from controls, and variance in DMSP concentrations within each experiment was very low. Although DMSP concentrations in U. lactuca may be affected by factors not tested in these experiments, it is also possible that the observed spatial differences reflect constitutive genotypic or phenotypic differences among geographically separated U. lactuca populations or among cryptic Ulva species.
Surviving information warfare attacks on databases

We consider the problem of surviving information warfare attacks on databases. We adopt a fault tolerance approach to the different phases of an attack. To maintain precise information about the attack, we mark data to reflect the severity of detected damage as well as the degree to which the damaged data has been repaired. In the case of partially repaired data, integrity constraints might be violated, but data is nonetheless available to support mission objectives. We define a notion of consistency suitable for databases in which some information is known to be damaged, and other information is known to be only partially repaired. We present a protocol for normal transactions with respect to the damage markings and show that consistency preserving normal transactions maintain database consistency in the presence of damage. We present an algorithm for taking consistent snapshots of databases under attack. The snapshot algorithm has the virtue of not interfering with countermeasure transactions.
Effects of Meat and Selected Food Components on the Valence of Nonheme Iron during In Vitro Digestion

Our objective was to determine whether meat and other dietary factors have the capacity to reduce nonheme ferric iron to the ferrous form during digestion. Beef, selected organic acids, selected purified proteins, red blood cells, whole blood, or blood plasma was mixed with FeCIJ and subjected to simulated gastrointestinal digestion. Ferrozine was used to monitor the formation of dialyzable Fe(H). Ascorbic acid, glutathione and cysteine produced large increases in Fe(H) while meat (raw and cooked), hemoglobin and red blood cells yielded smaller increases. Casein, plasma, bovine serum albumin and egg albumin did not affect Fe(I1) formation. Our Results suggest dietary factors which enhance iron absorption in vivo promote Fe(W) reduction in the intestinal lumen.
Analysis of Errors in a Comparator-Based Switched-Capacitor Biquad Filter

Comparator-based switched-capacitor (CBSC) techniques have become popular in reducing power consumption and increasing the speed of data converters. This brief investigates the use of CBSC techniques for implementing a biquad filter. A CBSC implementation of a low-pass biquad is proposed, and the sources of error are analyzed. It is shown that implementing the lossy integrator as the last stage produces a lower offset voltage. The sensitivity of the biquad omega0 and Q to the CBSC overshoot error is shown to be similar to that of the finite operational amplifier gain error in a switched-capacitor filter. Simulation results confirm the presented theory.
Scanning electron microscopy of Drosophila melanogaster embryogenesis. III. Formation of the head and caudal segments.

Abstract The formation of both the anterior most and posterior most segments in higher dipteran embryos involves complex movements of primordia which can be best visualized with the scanning electron microscope. During head formation, the gnathocephalic segments partially involute through the stomodeum. The labial segment forms the floor of the mouth, and the fused maxillary and mandibular segments form the lateral sides of the mouth. The involuted clypeolabrum forms the roof of the mouth. Invaginations of cells for segmentally derived sense organs can be found prior to involution on all the gnathocephalic and thoracic segments as well as on the labrum. The antennal sense organ derives from the lateral surface of the procephalic lobe. Following involution of the mouth parts, the dorsal ridge, which arises just anterior to the first thoracic segment, is drawn over the dorsal procephalic lobe producing the deep dorsal sac. The optic lobes of the brain invaginate anterior to the dorsal ridge just prior to the covering over of the head. The formation of the anal segment is similarly complex. Two rudimentary segments are found posterior to the eighth abdominal segment. During shortening of the germ band, the posterior most segment is drawn around the posterior tip of the embryo to lie ventrally. Two large anal pads form lateral to the anus from this segment. The next segment, following dorsal closure, produces a pair of anal sense organs and a central tuft of setae. Finally, the eighth abdominal segment gives rise to the posterior spiracles. Following dorsal closure these three segments fuse to produce the terminal (anal) segment of the larva.
Ultrafast high-intensity lasers

This tutorial will review the development of ultrafast high-intensity lasers and the technologies that make them possible. Topics will include a review of ultrashort pulse oscillators, control of high-order dispersion and spectral reshaping, selection of ultrafast compatible optical materials and components, management of thermal distortions and beam quality, and development of new pulse measurement and characterization technologies. A brief review of future systems including those being designed to reach petawatt peak powers with single-Hz repetition rates and terawatt peak powers at kHz repetition rates will also be presented.
Efficient distributed linear programming with limited disclosure

In today's networked world, resource providers and consumers are distributed globally and locally. However, with resource constraints, optimization is necessary to ensure the best possible usage of such scarce resources. Distributed linear programming (DisLP) problems allow collaborative agents to jointly maximize profits (or minimize costs) with a linear objective function while conforming to several shared as well as local linear constraints. Since each agent's share of the global constraints and the local constraints generally refer to its private limitations or capacities, serious privacy problems may arise if such information is revealed. While there have been some solutions proposed that allow secure computation of such problems, they typically rely on inefficient protocols with enormous communication cost. In this paper, we present a secure and extremely efficient protocol to solve DisLP problems where constraints are arbitrarily partitioned and no variable is shared between agents. In the entire protocol, each agent learns only a partial solution (about its variables), but learns nothing about the private input/output of other agents, assuming semi-honest behavior. We present a rigorous security proof and communication cost analysis for our protocol and experimentally validate the costs, demonstrating its robustness.
HIV and AIDS-related stigma in the context of family support and race in South Africa.

Objectives. In this paper, we describe the first phase of a research project designed to quantify the role of race and cultural identity in HIV-related stigma. The ultimate purpose is to develop an intervention that could be implemented in Black and Colored communities in Cape Town, South Africa. Design. The PEN-3 model provided the theoretical basis for this research. A total of 397 Black and Colored participants were recruited from two communities to complete a 16-item multi-part questionnaire that was developed based on focus groups and key informant interviews. A total of 196 questionnaires were administered in Mitchell's Plain and 201 were administered in Gugulethu. Both communities are located approximately 20 km outside the city of Cape Town in an area known as the Cape Flats. Data were collected on individuals' perceptions of stigma in the contexts of the family, healthcare settings, and the community. However, only the family context is explored here. Participants were also asked to identify what...