cssi/SciSciGPT-SciSciNet huggingface dataset:
Controlled release using a new bioerodible polyphosphazene matrix system

Polyphosphazenes possess polymer backbones consisting of nitrogen and phosphorous formally separated by alternating single and double bonds. Their potential for biomedical applications stems from the fact that polymers with a wide array of properties can be synthesized using the same starting compound, poly(dichlorophosphazene), through changes in side chain substituents, and that many of these compounds synthesized have been found to biodegrade to harmless products. In this article, studies of a novel monolithic bioerodible polyphosphazene matrix system for controlled drug delivery are presented. Poly(imidazole methylphenoxy) phosphazene is synthesized and shown to be bioerodible. The versatility of drug delivery devices fabricated using this polymer is shown through studies of release of macro-molecules and low molecular weight drugs. Initial histological evaluations of this particular polyphosphazene are also presented.
The necessity for adaptation in modified Boolean document retrieval systems

Abstract A document retrieval system may be described by three formal characteristics: the syntax employed to describe documents (keywords or vectors of weights, for instance), the form of machine-processable queries it accepts as valid (unordered sets of keywords, keywords with Boolean connectives or weighted vectors, for example), and the retrieval rules used to rank or retrieve documents. This article argues that the interdependence among document descriptions, queries, and retrieval rules requires adaptation for the system to perform effectively when one of its components changes. Recently, suggestions have been made to modify traditional Boolean document retrieval systems to allow more flexible queries and ranked document output. However, these new forms of queries and retrieval rules likely require that documents be described differently than they are in existing, commercial Boolean retrieval systems. A “genetic algorithm” is discussed as a means for redescribing documents. This probabilistic algorithm uses feedback along with alternative descriptions of a single document and takes account of the dependency structure of subject terms.
Disturbing the spin liquid state in Tb2Ti2O7: Heat capacity measurements on rare earth titanates

Abstract One of the best-known spin liquids is the geometrically frustrated pyrochlore Tb2Ti2O7. In a spin liquid, there are short-range dynamic magnetic correlations and an absence of static long-range magnetic order down to 0 K. We have measured heat capacity at low temperatures in magnetic field to 80 kOe on Nd2Ti2O7, Tb2Ti2O7, and Tb2TiO5 to better understand the spin liquid state. Nd2Ti2O7 displays antiferromagnetic order at T = 0.6 K much lower than the paramagnetic Curie temperature. Application of magnetic field or distortion of the Tb sublattice destroys the spin liquid as evidenced by static spins.
Ethylenediaminetetraacetic acid (EDTA) and caffeine are antagonistic to antirelaxin serum inhibition of porcine sperm motility

Sperm motility after treatment with antirelaxin serum (R6; 1:9000), EDTA (0.5 mM) and caffeine (3 mM) was investigated in both fresh and washed porcine spermatozoa. Sperm motility was assessed by a transmembrane migration ratio (TMMR) method. Motility of fresh and washed spermatozoa, incubated with normal rabbit serum (NRS, 1:9000), NRS+EDTA, NRS+caffeine, R6, R6+EDTA, R6+caffeine, respectively, was determined at 0, 10, 30 and 60 min after treatment. Antirelaxin serum abruptly inhibits (P < 0.05) sperm motility within 10 min compared with NRS, EDTA and caffeine treatments. However, the inhibitory action of antirelaxin serum on porcine sperm motility is neutralized by either EDTA or caffeine. These results suggest that the inhibitory action of antirelaxin serum on sperm motility may be mediated through a calcium- or a cyclic adenosine 3′,5′-monophosphate (cAMP)-dependent pathway.
Experimental and analytical energy and power flow using a scanning laser Doppler vibrometer

Many analytical solutions and experimental techniques have been developed which attempt to characterize the dynamics of a structure. In this study, the dynamics of the structure under test are characterized by the spatial representation of the energy flowing through the structure. The spatial representation of the energy or power flow may be used to define the flow of energy from the energy sources to sinks. Conceptually, once the energy path in the structure can be characterized, the structure can be designed to channel or dissipate energy to meet design goals. This concept is analogous to designing the load path of a structure in static design. In order to obtain an accurate spatial model of the power flow and determine points of energy sources and sinks, a high spatial density of the structure response is required. It is impractical to obtain a high spatial density of the response with the use of accelerometers or other structurally mounted measuring devices. In this experimental approach, a scanning laser Doppler vibrometer (LDV) acquires data used in developing a spatial three dimensional model of the steady-state dynamic response. The system response is represented by the three-dimensional complex valued velocity field. From this experimentally derived spatial dynamics model, an accurate representation of the structure's actual energy and power flow can be extracted. In this research, the underlying assumptions in the analytical methods of power flow for beams are discussed and their effects are quantified. A scanning LDV is used to make velocity measurements by scanning the entire beam structure from multiple scan positions. The experimental spatial dynamics modeling technique is used to solve for the three-dimensional complex velocity field of the vibrating beam. From this spatial representation of the dynamic response, the components of power flow due to the shear force and the bending moment are extracted and used to determine the total power flow along the beam. With the methods presented in this paper, a spatial model of the experimental energy and power flow can be determined.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Theoretical studies of the effects of grain noise on photographic stellar astrometry and photometry.

A method of incorporating the effects of photographic emulsion grain noise into digital image centering algorithms is presented which improves the accuracy of the derived stellar positions and magnitudes. Theoretical formulae are then derived for the limiting error of the center, and the photometric parameters. For IIIa-J, this error is 0.2-0.3 mu for bright unsaturated images, which agrees quite well with measurements made with the Yale PDS microdensitometer. It is expected that, with further improvements in the positional accuracy of the PDS, it should be possible to reach the emulsion grain noise limit, providing that emulsion shifts or other large scale errors do not dominate. It is also shown that, with appropriate trimming, marginal distribution image centering algorithms can yield an accuracy only slightly poorer than that obtained with two-dimensional distributions.
Inactivation of class A β-lactamases by clavulanic acid : the role of arginine-244 in a proposed nonconcerted sequence of events

From the refined 2 A crystal structure of the Bacillus licheniformis 749/C β-lactamase, energy-minimized models for active-site binding of the precatalytic («Michaelis») complex with the clinically utilized inactivator, clavulanic acid, for the acyl enzyme intermediate, and for the ultimate acylated acyclic species that leads to inactivation of class A β-lactamases by clavulanate have been generated. On the basis of these models, the details of the chemistry of inactivation of clavulanate are reassessed. A nonconcerted process for the inactivation chemistry of class A β-lactamases by clavulanate is proposed. These models reveal that the Arg-244 side chain and the Val-216 carbonyl anchor a structurally conserved water molecule, W673, which serves as the most likely source of a critical proton in a stepwise sequence of events
Plenary Speech: Micro- and Nano-Technologies for Automotive Research

In this talk, current and future research directions for micro- and nano-technologies applicable to the automotive sensor market will be presented. There exists an opportunity for new research to provide new micro- and nano-technologies that in the short run may not yet compete with the existing automotive sensor technologies, but in the long run are likely to surpass them. Historically, automotive sensor technology has been transitioning through three phases, from 1) early phases in which simple driver information is generated, to 2) computer-in-the-loop control systems to 3) complete driving experience mode selection. This existing technology is in phase 3, and for this phase to be successfully completed, new sensors that have higher resolution, greater bandwidth and lower cost must be developed. The new micro- and nano-technologies will provide that solution. A number of micro- and nano-sensors, currently under development, will be described and reviewed. These include 1) resonant micro strain sensors to determine the smallest deflections of even the most rigid of metal automotive parts, 2) micro sensors that show promise of measuring temperature, acceleration, pressure and strain inside the automobile engine combustion chamber, 3) nanowire and nanotube sensors made using a new, room temperature fabrication method that allows the nanowires and nanotubes to be fabricated directly on CMOS chips and 4) miniaturized, low-cost, micro RF systems to detect the presence of pedestrians in the path of the vehicle. These sensors, and others, promise to revolutionize the automotive sensor market.
An infrared spectroscopic study of the metal binding in some valine chelates

The IR spectra of some metalvaline chelates have been investigated from 3600–250 cm−1 and empirical assignments for observed bands relevant to the chelation binding have been accomplished. The configurations of the chelates have been deduced. From the variations in the metalnitrogen stretching and NH2 stretching frequencies, the periodic series trend in metalnitrogen bond strengths is shown to be Co(II) Zn(II), in accord with the Irving-Williams order. The group variation, Zn(II)<Cd(II)<Hg(II), reflects an increase in metalnitrogen bond strengths with increasing softness of the metal ion. Using the frequency separation for the carboxylate stretching vibrations, the soft Hg(II) and Cd(II) are shown to bind relatively weakly with oxygen whereas the relatively hard Co(II) is more strongly bound.
Secondary Traits: Sire Evaluation and the Reproductive Complex

Genetic aspects of dystocia, reproduction and its association with production, and calf livability are reviewed. Measures of each are presented. Genetic and maternal effects, sire evaluation by births from heifers and older cows, and correlations with production and type are discussed for dystocia. Heritabilities for measures of reproduction were low. Fertility and production were antagonistic in cows but complementary between heifer breedings and production in first lactation. There were differences among sires for calf mortality up to 48 h after birth, but heritabilities were low. Livability and dystocia are closely correlated genetically. Methods for multiple traits ideally should be used for sire evaluation.
Second harmonic a.c. polarography: Theoretical predictions for systems with first-order chemical reactions preceding the charge transfer step

Summary Theoretical predictions for the second harmonic a.c. polarographic responseof systems involving rate control by diffusion, a first-order preceding chemical reaction and/or heterogeneous charge transfer kinetics are presented and discussed. A rigorous solution of the expanding plane boundary value problem by the Matsuda method is the basis of the theoretical formulation employed. The predicted second harmonic behavior, including both amplitude and phase characteristics, is examined for a wide range of kinetic conditions encompassing both nernstian and non-nernstian behavior. Properties of the second harmonic response which make its observation eminently useful in quantitatively characterizing kinetics of homogeneous chemical reactions preceding heterogeneous charge transfer are made apparent.
Phenolic acids are in vivo atheroprotective compounds appearing in the serum of rats after blueberry consumption.

Blueberries (BB) have recently been shown to have cardioprotective effects and to prevent atherosclerosis in rodent models. However, the bioactive compounds in BB responsible for these effects have not yet been characterized. Seven phenolic acids (7PA) were identified as metabolites in the serum of rats fed diets supplemented with 10% freeze-dried BB. In this study, 7PA were evaluated for their potential atheroprotective effects in murine macrophage cell line RAW 264.7. 7PA were found to inhibit LPS-induced mRNA expression and protein levels of pro-inflammatory cytokine TNF-α and IL-6 by reducing MAPK JNK, p38, and Erk1/2 phosphorylation. After treatment with 7PA for 2 weeks, mRNA expression and protein levels of scavenger receptor CD36 were decreased (P < 0.05), whereas type A scavenger receptor (SR-A) remained unchanged. Moreover, foam cell formation induced by oxLDL and oxLDL binding to macrophages was also inhibited by 7PA. In addition, 7PA increased (P < 0.05) expression and protein levels of ATP-bin...
Therapy of bacterial meningitis: principles and practice.

Since the advent of antimicrobial therapy, bacterial meningitis has changed from a disease with an almost uniformly fatal course to one in which the majority of patients now survive. The mortality rates for the three most common etiologic agents in bacterial meningitis, Hemophilus influenzae, N eisseria meningitidis and Streptococcus pneumoniae, were 6%, 10.3%, and 26.3%, respectively, in the United States from 1978 to 1981.1 Morbidity, however, primarily in the form of neurologic sequelae, continues to be a problem in children and adults surviving bacterial meningitis.2,3 This article focuses on the principles and practice of therapy in bacterial meningitis, highlighting the experience with new antimicrobial agents and the utility of adjunctive therapy.
Leukocyte Gene Expression in Patients with Medication Refractory Depression before and after Treatment with ECT or Isoflurane Anesthesia: A Pilot Study

Objective. To evaluate leukocyte gene expression for 9 selected genes (mRNAs) as biological markers in patients with medication refractory depression before and after treatment with ECT or isoflurane anesthesia (ISO). Methods. In a substudy of a nonrandomized open-label trial comparing effects of ECT to ISO therapy, blood samples were obtained before and after treatment from 22 patients with refractory depression, and leukocyte mRNA was assessed by quantitative PCR. Patients' mRNAs were also compared to 17 healthy controls. Results. Relative to controls, patients before treatment showed significantly higher IL10 and DBI and lower ADRA2A and ASIC3 mRNA (P < 0.025). Both ECT and ISO induced significant decreases after treatment in 4 genes: IL10, NR3C1, DRD4, and Sult1A1. After treatment, patients' DBI, ASIC3, and ADRA2A mRNA remained dysregulated. Conclusion. Significant differences from controls and/or significant changes after ECT or ISO treatment were observed for 7 of the 9 mRNAs studied. Decreased expression of 4 genes after effective treatment with either ECT or ISO suggests possible overlap of underlying mechanisms. Three genes showing dysregulation before and after treatment may be trait-like biomarkers of medication refractory depression. Gene expression for these patients has the potential to facilitate diagnosis, clarify pathophysiology, and identify potential biomarkers for treatment effects.
Dissolution Mechanism of Soda-Lime Silicate Glass and of PNL 76-68 in the Presence of Dissolved Mg

Leaching studies were performed on powdered PNL 76-68 glass in de-ionized water in the presence of Mg solute. The results showed that the presence of Mg in the leachant greatly reduced the rate of glass dissolution. The equation Q = kt{sup {alpha}} was used to express the experimental data. In the absence of Mg, {alpha} was about 1, i.e., the amount of glass dissolved was linear with time. In the presence of Mg, {alpha} was close to 0.5, i.e. the extracted amount was proportional to the square root of time. Therefore, the reduction of the dissolution rate of PNL 76-68 glass in the presence of Mg solute could be explained as a result of a change in the glass dissolution mechanism. Comparative leaching studies on bulk soda-lime silicate glass in a sodium borate buffered system (pH 8.1) showed the same results. The presence of Mg in the leachant reduced the rate of glass dissolution. In the absence of Mg, {alpha} was about 1, while in the presence of Mg, {alpha} was 0.5. This change in {alpha} was not caused by changes in pH, and it represents a real change in the glass dissolution mechanism.
Psychostimulants as Cognitive Enhancers: The Prefrontal Cortex, Catecholamines and Attention Deficit Hyperactivity Disorder

Psychostimulants exert behavioral-calming and cognition-enhancing actions in the treatment of attention-deficit/hyperactivity disorder (ADHD). Contrary to early views, extensive research demonstrates that these actions are not unique to ADHD. Specifically, when administered at low and clinically relevant doses, psychostimulants improve a variety of behavioral and cognitive processes dependent on the prefrontal cortex (PFC) in subjects with and without ADHD. Despite the longstanding clinical use of these drugs, the neural mechanisms underlying their cognition-enhancing/therapeutic actions have only recently begun to be examined. At behaviorally activating doses, psychostimulants produce large and widespread increases in extracellular levels of brain catecholamines. In contrast, cognition-enhancing doses of psychostimulants exert regionally restricted actions, elevating extracellular catecholamine levels and enhancing neuronal signal processing preferentially within the PFC. Additional evidence suggests a prominent role of PFC α 2 and D1 receptors in the behavioral and electrophysiological actions of low-dose psychostimulants. These and other observations indicate a pivotal role of PFC catecholamines in the cognition-enhancing and therapeutic actions of psychostimulants, as well as other drugs used in the treatment of ADHD. This information may be particularly relevant for the development of novel pharmacological treatments for ADHD and other conditions associated with PFC dysregulation.
Critical factors that determine face-centered cubic to body-centered cubic phase transformation in sputter-deposited austenitic stainless steel films

Bulk austenitic stainless steels (SS) have a face-centered cubic (fcc) structure. However, sputter deposited films synthesized using austenitic stainless steel targets usually exhibit body-centered cubic (bcc) structure or a mixture of fcc and bcc phases. This paper presents studies on the effect of processing parameters on the phase stability of 304 and 330 SS thin films. The 304 SS thin films with in-plane, biaxial residual stresses in the range of approximately 1 GPa (tensile) to approximately 300 MPa (compressive) exhibited only bcc structure. The retention of bcc 304 SS after high-temperature annealing followed by slow furnace cooling indicates depletion of Ni in as-sputtered 304 SS films. The 330 SS films sputtered at room temperature possess pure fcc phase. The Ni content and the substrate temperature during deposition are crucial factors in determining the phase stability in sputter deposited austenitic SS films.
Staphylococcus aureus and Bacillus subtilis W23 make polyribitol wall teichoic acids using different enzymatic pathways.

Wall teichoic acids (WTAs) are anionic polymers that play key roles in bacterial cell shape, cell division, envelope integrity, biofilm formation, and pathogenesis. B. subtilis W23 and S. aureus both make polyribitol-phosphate (RboP) WTAs and contain similar sets of biosynthetic genes. We use in vitro reconstitution combined with genetics to show that the pathways for WTA biosynthesis in B. subtilis W23 and S. aureus are different. S. aureus requires a glycerol-phosphate primase called TarF in order to make RboP-WTAs; B. subtilis W23 contains a TarF homolog, but this enzyme makes glycerol-phosphate polymers and is not involved in RboP-WTA synthesis. Instead, B. subtilis TarK functions in place of TarF to prime the WTA intermediate for chain extension by TarL. This work highlights the enzymatic diversity of the poorly characterized family of phosphotransferases involved in WTA biosynthesis in Gram-positive organisms.
Migmacell — A low-gain “driven” fusion power amplifier as an interim energy source

Abstract A fusion program less ambitous in its objectives and technology than the official programs, but such that it could be reduced to practice before the large “ignited” plasma fusion power reactors with “infinite gain” become a reality, is described. “Migmacell” is designed as a “driven” power amplifier, energized by fusion, with a gain of 1.5–3. By recirculating a significant fraction of the output power, migmacell is a small (1 m in diam.), self-sustained power source of 100 kW e to 5 MW e . By using direct nuclear collisions in “self-colliding orbits”, it operates at the equivalent kinetic “temperatures” at least 100 times higher than thermonuclear devices. From the point of view of plasma physics, migmacell is a simple “colliding-beam” mirror with large gyroradius, highly non-adiabatic orbits and highly non-isotropic density, peaked at the center. Focusing action results in low classical end-losses compared to plasma mirrors. The fusion power density is high, 0.1 kW/cm 3 . Diamagnetic effects are confined mostly to the central region, where they cause a min-B well. High-energy migma fusion renders it possible to utilize the environmentally acceptable “advanced fuels” such as D, 3 He or boron, rather than D-T, thus lending itself to a “clean fusion” power source which is neutron-free or neutron-deficient. Larger plants are envisioned as a plurality of standardized migma-cells, thus solving many problems in power transmission and distribution. Three stages of the program are completed. The experimentally achieved collision energy of ∼1 MeV (equivalent kinetic “temperature” of 10 10 °K) and the energy confinement time of (2.21±0.05) s are sufficient for an advanced-fuel fusion reactor, but the central density of (2.2±0.7)×10 9 d + /cm 3 , limited by the vacuum and the injection rate, is low. The colliding beam luminosity (rate per σ=1) is L =10 27 cm −2 s −1 . Apparatus for Stage 4 (1 year program) whose aim is to achieve a large density regime ( ω pi / ω ci ) 2 ⪢10, has been assembled and tested. Stage 5 is (a 5 year program) aims to build a demonstration power unit. Economic projections indicate a competitive power source. State-of-the-art technology is assumed throughout.
Relationship of the structure of slide valve periclase plates to their metal resistance

The interaction of the original structure of periclase refractories, which is dependent upon their purity and structure, with the high temperature strength and metal resistance, was established. It was shown that samples of high purity fused periclase, in the structure of which coarse grains of fragmental structure predominate, had the highest resistance to the action of molten iron.
Empirical Bayes Estimation with Random Censoring

Abstract We study empirical Bayes estimation for exponential distributions based on randomly censored data. An empirical Bayes estimator is constructed. The rate of asymptotic optimality of is investigated. It is shown that under certain conditions, the regret of converges to zero at a rate O(ln4 n/n 1/2), where n is the number of past data available when the present estimation problem is considered.
Productivity tools in the development and transfer of computer applications: State of the art and practice

Abstract Two aspects of system productivity exist: productivity of the system development process and the system's impact on the productivity of the organization as a whole. The theory and practice in measuring both aspects of systems productivity is discussed. Over the past decades generations of development tools have evolved. The goal of these tools is to improve the productivity of system development. More recently, the role of development tools in improving organizational productivity is being addressed. Attributes and usage of current tools are discussed. A new generation of development tools, which are integrated, friendly, and intelligent, is discussed. Finally, a representative sample of the new generation tools is discussed along with related theory.
Posttranslational regulation of cyclooxygenase by tyrosine phosphorylation in cerebral endothelial cells.

Endothelium-derived cyclooxygenase (COX) products regulate cerebral vascular tone in newborn pigs. Both COX-1 and COX-2 are constitutively expressed in endothelial cells from newborn pig cerebral m...
Are today's Millennials splintering into a new generational cohort? Maybe!

A new generational cohort is emerging from the Millennial market segment as a result of cataclysmic events that have occurred since 2008. Interviews with college upperclassmen in the United States identified significant events influencing their values, the values arising from these events, and new values not associated with older Millennials. The most important events identified included the Great Recession, 9/11, and the election of the first African-American president. Values of Millennials were assessed in online surveys of college juniors and seniors in the United States in the fall of 2009 and 2010 and among older Millennials, aged 27–31, during the summer of 2010. The values most strongly differentiating the younger and older Millennials were “piety” and “thrift.” Younger Millennials in the United States are less thrifty and more secular and sexually permissive than older Millennials. They are also less patriotic and less concerned about politics, sustainability, saving, and making mistakes in life. This suggests a splintering of the Millennials cohort as a result of the Great Recession and the potential emergence of a younger “entitlement” cohort. It also suggests further investigation of cross-national value shifts among younger Millennials, prompted by the Great Recession. Copyright © 2012 John Wiley & Sons, Ltd.
Display of 3D information in discrete 3D scenes produced by computerized tomography

Imaging modalities such as X-ray computerized tomography (CT), ultrasound CT, and nuclear magnetic resonance CT all produce sequences of slice images of internal structures of medical objects. Effective methods of displaying the 3D information in such images are essential to aid in both diagnosis and treatment of diseases. Two philosophically different approaches to the display problem have been pursued. In the first approach, 3D information is displayed as a distribution of densities in a 3D space. The second approach extracts, from slice images, information about boundary surfaces of objects which is displayed on a 2D screen. The present paper reviews both of these approaches with particular emphasis on the image and graphics processing aspects of the latter approach.
Negative Mood, Perceived Self-Efficacy, and Personal Standards in Dysphoria: The Effects of Contextual Cues on Self-Defeating Patterns of Cognition

The present study investigated the effects of mood-related cues on the relation between performance standards and self-efficacy perceptions in dysphoric and nondysphoric individuals. Participants' personal standards and self-efficacy perceptions for various everyday activities were assessed. In the absence of mood-related cues, dysphoric participants, unlike nondysphorics, held standards that slightly exceeded their self-efficacy perceptions. A cue that highlighted the potential influence of mood on self-judgments eliminated the difference between dysphoric and nondysphoric participants. A cue that highlighted a potential external source of current mood magnified the group difference, leading dysphoric individuals to strongly exhibit a “self-defeating” cognitive pattern in which they adopted standards that far exceeded their self-efficacy levels. The cues also moderated the strength of relations between mood and personal standards. Current affect appears to play a role in the construction of standards and self-efficacy perceptions, and different affective processes may operate in the self-judgments of dysphoric versus nondysphoric individuals.
Fluency, Familiarity, Aging, and the Illusion of Truth

Research has shown that repeated statements are rated as more credible than new statements. However, little research has examined whether such “illusions of truth” can be produced by contextual (nonmnemonic) influences, or compared to the magnitude of these illusions in younger and older adults. In two experiments, we examined how manipulations of perceptual and conceptual fluency influenced truth and familiarity ratings made by young and older adults. Stimuli were claims about companies or products varying in normative familiarity. Results showed only small effects of perceptual fluency on rated truth or familiarity. In contrast, manipulating conceptual fluency via semantic/textual context had much larger effects on rated truth and familiarity, with the effects modulated by normative company familiarity such that fluency biases were larger for lesser-known companies. In both experiments, young and older adults were equally susceptible to fluency-based biases.
The Effects of Extracellular Matrix Protein Insufficiency and Treatment on the Stiffness of Arterial Smooth Muscle Cells

Increased arterial stiffness is directly correlated with hypertension and cardiovascular disease. Stiffness of the conducting arteries is largely determined by the extracellular matrix (ECM) proteins in the wall, such as collagen and elastin, produced by the smooth muscle cells (SMCs) found in the medial layer. Elastin is deposited as soluble tropoelastin and is later crosslinked into elastin fibers. Newborn mice lacking the elastin protein (Eln−/−) have increased arterial wall stiffness and SMCs with altered proliferation, migration and morphology [1]. Vessel elasticity is also mediated by other ECM proteins, such as fibulin-4. Elastic tissue, such as lung, skin, and arteries, from fibulin-4 deficient (Fbln4−/−) mice show no decrease in elastin content, but have reduced elasticity due to disrupted elastin fibers [2]. Arteries from both elastin and fibulin-4 deficient mice have been previously studied, but the mechanical properties of their SMCs have not been investigated. Recent experiments comparing arterial SMCs from old and young animals suggest that mechanical properties of the SMCs themselves may contribute to changes in wall stiffness [3]. Hence, we investigated the stiffness of isolated arterial SMCs from elastin and fibulin-4 deficient mice using atomic force microscopy (AFM). In addition, we studied the effects of two elastin treatments on the mechanical properties of SMCs from Eln+/+ and Eln−/− mice. Differences between the treatments may elucidate the importance of soluble versus crosslinked elastin on single cell stiffness.Copyright © 2013 by ASME
IMPROVED TESTS FOR HETEROGENEITY ACROSS A REGION OF DNA SEQUENCE IN THE RATIO OF POLYMORPHISM TO DIVERGENCE

The neutral theory of molecular evolution predicts that the ratio of polymorphisms to fixed differences should be fairly uniform across a region of DNA sequence. Significant heterogeneity in this ratio can indicate the effects of balancing selection, selective sweeps, mildly deleterious mutations, or background selection. Comparing an observed heterogeneity statistic with simulations of the heterogeneity resulting from random phylogenetic and sampling variation provides a test of the statistical significance of the observed pattern. When simulated data sets containing heterogeneity in the polymorphism-to-divergence ratio are examined, different statistics are most powerful for detecting different patterns of heterogeneity. The number of runs is most powerful for detecting patterns containing several peaks of polymorphism; the Kolmogorov-Smirnov statistic is most powerful for detecting patterns in which one end of the gene has high polymorphism and the other end has low polymorphism; and a newly developed statistic, the mean sliding G statistic, is most powerful for detecting patterns containing one or two peaks of polymorphism with reduced polymorphism on either side. Nine out of 27 genes from the Drosophila melanogaster subgroup exhibit heterogeneity that is significant under at least one of these three tests, with five of the nine remaining significant after a correction for multiple comparisons, suggesting that detectable evidence for the effects of some kind of selection is fairly common.
Adaptive resource management for DS-CDMA networks subject to energy constraints

We consider a time-slotted DS-CDMA network consisting of a single radio access point and a finite number of mobile wireless terminals. The terminals generate non-real-time packet data and transmit, subject to constraints on the average energy consumed per packet transmission, in a random access fashion over a common broadband channel to the access point using different spreading codes. As in narrowband ALOHA systems, the performance of random access spread spectrum networks can be severely hampered due to saturation effects caused by inherent bistable behavior. We study the effect of dynamic spreading gain control on the stability and throughput properties of the network. We first impose no energy constraints and provide an optimal (throughput maximizing) algorithm under which (i) the asymptotically optimal retransmission probability is equal to one, and (ii) the optimal spreading gain increases linearly as the multiaccess interference (MAI) level increases, or equivalently, the transmission rate decreases inverse linearly as the MAI level increases. We also obtain a simple closed-form expression for the asymptotic throughput as the number of backlogged terminals becomes large. We then impose energy constraints and modify the optimal algorithm by controlling both the spreading gain and retransmission probability of the terminals. The resulting algorithm may or may not eliminate bistability; however, in either case, it achieves high throughput.
Staying Alive: Adult Literacy Programs and Child Mortality in Rural Ghana

Summary This paper estimates the causal effect of maternal participation in adult literacy programs on child mortality in rural Ghana, taking into account the possible endogeneity of program participation and endogenous program placement. Adult literacy program participation has a substantial impact on child mortality and is also cost-effective in reducing child mortality. The combined results of this paper point toward the potentially important role of adult literacy programs in promoting child health in Ghana through the acquisition of health knowledge by participants—in stark contrast with the decreased attention toward such programs in the developing world in recent years.
Prevaccination Serologic Screening for Measles in Health Care Workers

A model was developed from which the cost-effectiveness of prevaccination serologic screening for measles could be estimated, for any combination of antibody screening costs and prevalence of antibody to measles. This model was tested using sera obtained prospectively from 222 health care workers, including 181 born in or after 1957 who had no history of measles, no measles vaccine after 1980, and no documentation of immunity to measles. In addition, 41 subjects born before 1957 who had no history of measles were studied. A rapid, reliable, and inexpensive ($5 per test) commercial ELISA was used to test for antibodies to measles; its seroprevalence in the subject population was 86%. From the model, it was estimated that prevaccination serologic testing would be cost-effective if antibody screening cost less than or equal to $12.75 per test. In this subject population, prevaccination serologic screening for measles was cost-effective.
Comparison of flexible ureteroscopes: deflection, irrigant flow and optical characteristics.

ABSTRACTPurpose:: We measured and compared the deflection, irrigation flow rates, distortion, resolution and light transmission of new generation flexible ureteroscopes.Materials and Methods:: Multiple characteristics of 5 flexible ureteroscopes (ACMI DUR-8 Elite™, Olympus URF-P3™, Storz 11278AU1™ [Flex-X], Wolf 7330.072™ and Wolf 7325.172™) commonly available in the market were measured and compared. Measured data included active deflection, irrigation flow rates and optical characteristics. Each ureteroscope was evaluated with an empty working channel and with various accessories. Optical characteristics, specifically resolution and distortion, were measured using test targets (Edmund Optics, Barrington, New Jersey). Light transmission was also measured from the ureteroscope tip at 50% and 100% intensity. All 5 flexible ureteroscopes were tested in a laboratory setting using a Storz OR 1™ system to capture the images.Results:: For all 5 ureteroscopes the angle of deflection was most impaired by a 365 μm...
Associations Between Echocardiographic Arterial Compliance and Incident Cardiovascular Disease in Blacks: The ARIC Study

Systemic arterial compliance, the systolic to diastolic change in volume divided by the change in pressure, is a measure of vascular function that may be used to predict cardiovascular outcomes. The gold standard method of measurement, quantifying stroke volume and aortic pulse pressure (PP) invasively by thermodilution and catheter manometers, is a validated index of total arterial compliance.1,2 However, noninvasive estimates of systemic arterial compliance can be derived by the ratio of echocardiographic stroke volume and brachial arterial PP (SV/PP).2 Although noninvasive estimates of arterial compliance are well suited for prospective screenings and longitudinal epidemiologic studies, most observations relating arterial compliance and cardiovascular disease (CVD) have been drawn from cross-sectional analyses. Age,3,4 hypertension,5 concentric left ventricular hypertrophy,6 diastolic left ventricular dysfunction,7–9 hypercholesterolemia,10 fasting insulin,7,11 and Framingham risk score12 have all been associated with echocardiographic arterial compliance. Prospective analyses of echocardiographic arterial compliance have primarily been limited to Europeans but have predicted mortality in patients with diabetes13 and fatal and nonfatal cardiovascular events in hypertensives14,15 and in the general population.8 To date, few studies have assessed echocardiographic systemic arterial compliance in blacks, and none have analyzed cardiovascular events as explicit, rather than composite, outcomes. We analyzed associations between echocardiographic arterial compliance and incident stroke, heart failure, and coronary events in a cohort of blacks free of prevalent CVD and followed prospectively by the Atherosclerosis Risk in Communities (ARIC) study. We also compared the risks of cardiovascular outcomes associated with arterial compliance with those associated with PP and examined model performances to compare the predictive validity of echocardiographic arterial compliance and PP models.
A critical examination of best dose analysis for determining cognitive-enhancing potential of drugs: studies with rhesus monkeys and computer simulations

Best dose analysis involves identifying the dose associated with the greatest improvement in performance for each subject and comparing performances associated with these individually determined best doses to control performances. The current experiments were conducted to examine whether significant best dose effects might result from the selective analysis of data rather than an actual drug effect. Experiment 1 examined the effects of nicotine and methylphenidate on delayed matching-to-sample (DMTS) and self-ordered spatial search (SOSS) performances in rhesus monkeys (DMTS: n = 7; SOSS: n = 6) to determine the validity and reliability of best dose effects. Experiment 2 used Monte Carlo computer simulations to estimate the likelihood of obtaining a significant outcome when the best dose method was applied to randomly generated data sets for which no difference existed. Significant effects were obtained when the best dose analysis was applied to performances from nondrug sessions, and best dose performances were not significantly different from the best nondrug performances. The doses identified as best doses from two nicotine dose–response curve determinations were unrelated, and the improvement associated with the best dose observed during the first dose–response curve determination was not reliable when the dose was administered repeatedly. Finally, there was a high likelihood of obtaining a statistically significant difference when no real difference existed. Best dose analysis for the identification of potential therapeutic agents should be replaced by single-subject designs.
A model for pilot control behavior in analyzing potential loss-of-control events

An adaptive model of the human pilot engaged in pursuit tracking tasks that was previously introduced in the literature is modified and applied to the analysis of piloted control of a realistic transport aircraft model. As described, the pilot model requires no guesswork on the part of the analyst as regards initial parameter settings. By means of computer simulation, the adaptive pilot model is shown to exhibit superior performance to its non-adaptive counterpart in a series of configuration changes associated with the vehicle model. The overall validity of the post-adaptive pilot model is assessed by examining the resulting open-loop pilot vehicle dynamics in comparison to that predicted by the crossover model of the human pilot. The pilot modeling approach is proposed as a preliminary analytical tool to be used in the assessment of robust flight control system designs subject to faults or system failures with an eye toward potential loss-of-control.
Proof, Amazement, and the Unexpected

Archimedes is now best known for shouting "Eureka" in the bath, and perhaps also for his invention of the cunning machines that helped to defend Syracuse from the Roman fleet during the Punic Wars in 212 BP. He is less famous for his most profound work--the subtle deductions and rigorous, often counterintuitive, mathematical proofs of seemingly prosaic problems. His path-breaking work has reached new prominence among scholars with the rediscovery of a long-lost palimpsest copy of some of his writings, which for the first time shows that Greek mathematicians could work with infinite sets of numbers.
The Influence of Genetic Background and the Homologous Chromosome 17 on t-Haplotype Transmission Ratio Distortion in Mice

Transmission ratio distortion is a characteristic of complete t-haplotypes, such that heterozygous males preferentially transmit the t-haplotype bearing chromosome 17 to the majority of their progeny. At least two genes contained within the t-haplotype have been identified as being required for such high transmission ratios. In this study we examine the effects of the genetic background and the chromosome homologous to the t-haplotype on transmission ratio distortion. We use two different congenic lines: (1) BTBRTF/Nev.Ttf/t12, in which the t 12 haplotype has a transmission ratio of 52%, and (2) C3H/DiSn. Ttf/t12, in which the t12 haplotype has a transmission ratio of 99%. By intercrossing these two strains to produce reciprocal F1 and F2 generations, we have isolated the effects of the homologous chromosome 17 from the effects of the genetic background. We demonstrate that both the homologous chromosome and the genetic background have profound effects on t-haplotype transmission ratio distortion. Furthermore, it is evident that the t-haplotype transmission ratio behaves as a quantitative character rather than an intrinsic property of t-haplotypes.
How ants turn information into food

Organisms that can more effectively exploit information about their environments to improve foraging success have a competitive and selective advantage over others. Thus, animals are expected to evolve strategies that use information to improve foraging success. We study how desert seed harvesters use information to improve the rate they collect seeds, which contributes to the colony's fitness. Through field studies and computer simulations, we manipulated the information available to the ants in the spatial distribution of seeds and measured the resulting foraging rates. In field observations, seeds were collected faster when seeds could be found with less information. The increase in foraging rate with clustering was indistinguishable across three related species that vary over an order of magnitude in colony size. Computer simulations show similar systematic increases in foraging rates when information about the food location is communicated among nestmates.
Nonlinear optics and quantum entanglement of ultra-slow photons

Summary form only given. Exciting observations of ultra-slow group velocities and very large nonlinearities in coherently driven atomic media open up interesting prospectives for nonlinear optical processes at low light levels. Recent experiments, for instance, demonstrated that very efficient nonlinear phenomena can be induced by laser fields of tiny energies. These developments stimulate the studies of ultimate efficiency limits for nonlinear optics based on electromagnetically induced transparency (EIT) as well as its possible applications for generation and manipulation of quantum entangled states of the light fields and matter. We describe a particular method that allows for two slow light fields of energies corresponding to that of a "single photon" to interact coherently.
Generation of bladder contractions via electrical stimulation of urethral afferent nerves and intra-urethral stimulation

Neurological disease or spinal cord injury (SCI) can eliminate voluntary bladder control. Our long-term mission is to develop neural prostheses for restoration or neuro-rehabilitation of bladder function based on stimulation of afferent neural pathways that take advantage of native spinal neural circuitry. During voiding, urine flow in the urethra activates positive feedback reflexes that augment bladder contraction. This project sought to determine if electrical stimulation of urethral afferents could initiate bladder contractions and to develop a non-invasive method to investigate these responses in humans. In 3 cats, robust bladder contractions were generated by electrical stimulation of the urethral sensory nerves above a threshold bladder volume and at low (<5 Hz) stimulation frequencies. In 3 cats, a urethral catheter with a ring electrode was able to produce and maintain bladder contractions in the proximal and prostatic urethra via intra-urethral electrical stimulation. These results support the feasibility of the catheter-based method to investigate these effects in humans with spinal cord injury.