cssi/SciSciGPT-SciSciNet huggingface dataset:
Characteristics of Nanopatterns and the Associated Thermal Mechanisms During Near Field Laser-Material Interaction of Nanosecond Laser on Different Targets

Nano-patterns are generated on semiconducting and metallic surfaces through coupling an apertured near field scanning optical microscope (NSOM) with a pulsed laser source in this study. To understand the dominant mechanisms for the generation of the nano-patterns, a series of experimental measurement of the size and shape of nano-patterns generated on targets under different experimental conditions with different targets is conducted. The characteristic dimensions of nano-patterns show dependence on optical properties of the target material. The qualitative trend of the variation of nano-patterns as a function of laser and material conditions indicates that the dominant mechanisms for the generation of nano-patterns through a combination of nanosecond laser and an apertured NSOM under different conditions studied is near field laser-material interaction.Copyright © 2009 by ASME
The influence of transient surface fluxes on North Atlantic overturning in a coupled GCM Climate Change Experiment

The mechanism by which the model-simulated North Atlantic thermohaline circulation (THC) weakens in response to increasing greenhouse gas (GHG) forcing is investigated through the use of a set of five multi-century experiments. Using a coarse resolution version of the GFDL coupled climate model, the role of various surface fluxes in weakening the THC is assessed. Changes in net surface freshwater fluxes (precipitation, evaporation, and runoff from land) are found to be the dominant cause for the model's THC weakening. Surface heat flux changes brought about by rising GHG levels also contribute to THC weakening, but are of secondary importance. Wind stress variations have negligible impact on the THC's strength in the transient GHG experiment.
Capacitance effects in porous media

The velocity dependence of parameters in the Coats-Smith model for tracer dispersion and tailing in porous media was investigated. An axisymmetric pore with a step change in cross-sectional area was used as a model system to determine whether the stagnant zone resulting from variations in flow cross sections contributes to the observed capacitance (i.e., tailing) at the pore level. Numerical simulations show that eddies with circulation flow are formed in the pockets as a result of flow separation. The tracer transport between the eddies in the dead zones and the main channel was found to be diffusion-limited. The simulations reveal that in the Stokes flow regime, the mass-transfer coefficient between the two regions is independent of the interstitial velocity, in contradiction to earlier theories. Coreflood experiments were performed with radioactive tracers to verify the hypothesis that the capacitance effects are not the result of a change in flowing fraction. The experimental results confirm that tracer trailing is a function of the ratio of the molecular diffusivity to the flow rate. In light of these findings, the authors investigated the validity of the Coats-Smith model to predict dispersion and tailing in a porous medium. The authors' studies show that the Coats-Smithmore » model may be used; however, certain restrictions, described in this paper, apply to the procedure for estimation of parameters.« less
An angiotensin converting enzyme inhibitor is a tight-binding slow substrate of carboxypeptidase A.

Abstract Carboxypeptidase A-catalyzed hydrolysis of peptides and depsipeptides is competitively inhibited by N-(1-carboxy-5-t-butyloxycarbonylaminopentyl)-L-phenylalanine (Boc-CA-Phe, Ki = 1.3 μM) and the angiotensin converting enzyme inhibitor, N-(1-carboxy-5-carbobenzoxyaminopentyl)-glycyl-L-phenylalanine (Z-CA-Gly-Phe, Ki = 4.5 μM). The latter compound is actually a slow substrate of carboxypeptidase. Indirect observation of inhibitor binding by stopped-flow measurement of radiationless energy transfer between carboxypeptidase tryptophans and dansylated substrates reveals slow binding for both compounds. The visible absorption spectrum of the complex of cobalt(II)-substituted carboxypeptidase and Z-CA-Gly-Phe, which differs from the corresponding spectrum of the Boc-CA-Phe complex, is remarkable in its resemblance to the spectrum of the complex between Co(II)carboxypeptidase and a transient intermediate previously observed during hydrolysis of peptide substrates. The spectrum slowly changes to that of the free enzyme indicating hydrolysis. Chromatographic quantitation of substrate and products confirms that carboxypeptidase converts Z-CA-Gly-Phe to Z-CA-Gly and L-Phe with an apparent kcat of 0.02 s−1. Absorption spectroscopy indicates that the Z-CA-Gly-Phe-Co(II)carboxypeptidase spectrum is not that of bound products. Moreover, spectral titrations indicate that the products (both with spectral Ki values of about 3 mM), as well as D-Phe, compete for the same site on the enzyme.
Biomimetic composites via molecular scale self-assembly and biomineralization

New composite material designs are being inspired by the light weight, mechanically robust and unique functions of material systems in Nature. To gain access to these designs, new insight into these structures and their functions, coupled with bottom-up or molecular scale designs, are being implemented. While the synthesis of biomimetic material composites based on these concepts is embryonic, the integration of these concepts into broader materials science and engineering needs will continue to grow.
The dynamic digital disk

The DVD (digital versatile disk) standard was the first format to truly unite the computer and consumer electronics environments-but it also launched an unprecedented debate about copy protection. The DVD is much more than just a new and improved version of the CD. Advances in optical storage, signal processing, and disc manufacturing technology have emerged in the 15 years or so since the CD's birth, and the new disc includes or builds on many of them. But DVD has also been a wake-up call for the motion picture and music industries, rousing them to ready their intellectual property for the new age of digital distribution of content. Four main specifications apply to the physical media itself: one each for the DVD-ROM, DVD-RAM, DVD-R, and DVD-RW. Next, at the logical layer, a common file system specification supports all applications. Named the Universal Disc Format (UDF), it was developed by the Optical Storage Trade Association, Santa Barbara, Calif. Together, the logical and physical layers support an overlying set of applications defined by the DVD-Video, DVD-Audio, and (as yet developmental) DVD-Professional specifications.
Is Prophylactic Surgery for Femoroacetabular Impingement Indicated?: A Systematic Review

Background:This is a systematic review to determine if prophylactic surgical intervention for asymptomatic patients with radiographic evidence of femoroacetabular impingement (FAI) is warranted to prevent early degenerative joint disease of the hip.Methods:A systematic search was performed from 1965 to 2013 in PubMed and EMBASE. Inclusion criteria were prospective or retrospective studies comparing skeletally mature asymptomatic patients with radiographic evidence of FAI treated with prophylactic hip arthroscopic surgery versus nonoperative management. A total of 840 references were identified from the searches. After detailed eligibility screening, none of the references met the eligibility criteria.Results:No trials were identified that met the criteria for inclusion in the review.Conclusion:There is a lack of available evidence to support surgical intervention for the treatment of FAI in asymptomatic patients. This article attempts to address this dilemma by reviewing the available literature to answer...
Factors predicting depression among Korean-American women in New York

A survey was administered to 262 women aged 35-55 years who had migrated to the U.S. within the last 10 years. The survey included measures of depression, acculturative stress, social support, self-esteem, education, income, age, and length of residence in the U.S. Hierarchical regression analyses in which demographic variables were introduced first indicated that age, education, and income were all significant predictors of depression, with age positively related to depression and education and income negatively related to depression. When acculturative stress, social support, and self-esteem were introduced on subsequent steps, only self-esteem explained significant additional variability in depression. Implications for prevention and treatment programs are discussed.
Lasers for Facial Rejuvenation

Laser and laser-like assisted facial rejuvenation has become very popular during the last decade. Although a myriad of techniques are available, such approaches can be divided into four basic approaches. There are those that (i) ablate the epidermis, cause dermal wounding, and provide a significant thermal effect (CO2 lasers); (ii) ablate the epidermis, cause dermal wounding, and minimal thermal effects (short pulsed Erbium:Ytrrium-Aluminum-Garnet [Er:YAG] lasers); (iii) ablate the epidermis, cause dermal wounding, and provide variable thermal effects (combined CO2/Er:YAG lasers, variable pulsed Er:YAG lasers, and ablative radiofrequency devices); and (iv) do not ablate the epidermis, cause dermal wounding, and provide minimal thermal effects (non-ablative lasers and light sources). Each of the four modalities has now been shown to be effective in promoting facial rejuvenation. As would be expected, each has some advantages and disadvantages. CO2 lasers, because they ablate the epidermis, cause a dermal wound, and provide a significant thermal effect, appear to be most useful for those individuals with advanced photoaged skin. Such lasers provide the greatest degree of skin tightening for these individuals. However, it is that very same thermal effect that leads to the possibility of delays in healing sometimes noted with these systems. Short pulsed Er:YAG lasers, because they promote so little thermal damage, when used in a superficial manner, lead to the possibility of quicker healing than is seen with CO2 lasers. However, less clinical improvement and more bleeding may be noted. Combined CO2/Er:YAG lasers, variable pulsed Er:YAG lasers, and ablative radiofrequency devices lead to an effect somewhere in between that of pulsed CO2 lasers and short pulsed Er:YAG lasers. The newest group of systems includes the non-ablative devices that do not ablate the epidermis, cause dermal wounding, and provide for a minimal thermal effect. This area of technology is still evolving. Although such techniques, because they do not ablate the epidermis, are cosmetically elegant, the clinical results are usually not quite as good as the more aggressive ablative techniques.
The IRAS Colors of Normal Galaxies

In the IRAS color-color diagram, galaxies powered only by star formation are distributed in a band such that as systems get cooler at 12/25 microns they get warmer at 60/100 microns. A simple phenomenology is proposed which describes the emission from each galaxy as a combination of two components: cool, relatively constant 'cirrus' emission from the neutral medium, and from 'active' regions warmer emission whose colors depend on mean physical parameters in these regions. The model accounts for the IRAS colors of all galaxies detected as point sources in all four bands. The model implies that a galaxy's far-infrared flux as measured by IRAS is not simply proportional to the recent star formation rate, because only a (variable) fraction of the infrared is due to massive young stars, and only part of these stars' luminosity is reemitted in the infrared.
Metric between buckling structures and elastic properties in physisorbed polymer-tethered lipid monolayers

The current study reports the use of buckling structures as a measure of film elasticity on physisorbed, solid-supported polymer-tethered lipid monolayers consisting of phospholipids and poly(ethylene glycol) (PEG) lipopolymers. These monolayer systems, built using the Langmuir–Blodgett (LB) technique, exhibit buckles over a wide range of lipopolymer concentrations. Systematic quantitative analysis of the buckling structures using epifluorescence microscopy and atomic force microscopy reveals that increased lipopolymer concentrations are associated with higher area fractions of buckling regions. Quantitative analyses of buckling profiles show, furthermore, that enhanced lipopolymer concentrations lead to increased buckling widths without notably altering buckling amplitude. On the basis of these experimentally determined buckling parameters, we are able to derive a metric between elastic properties and buckling structures in the polymer-tethered lipid monolayer system. This is achieved by combining mean-field calculations of elastic properties of polymer-tethered lipid membranes with buckling theory of an Euler column. Our findings are significant because they provide new insight into the fascinating materials properties of polymer-lipid supramolecular assemblies and represent a tool for the characterization of elastic properties in complex biomembrane-mimicking film architectures with buckling structures.
Alanine-induced amino acid interrelationships.

Abstract Six normal subjects received 10 g of alanine both orally and as a 60-min intravenous infusion. In both studies blood samples for hormones and substrates were obtained every thirty minutes for 2 1 2 hr . Significant increases in whole blood levels of threonine, serine, glutamine, proline, glycine, and α-amino-n-butyric acid were found, which were mainly due to increases of these amino acids in the plasma compartment. In contrast, whole blood levels of leucine, valine, and isoleucine declined, mainly due to decreases in the cell compartment. Plasma glucagon levels increased in both studies while insulin levels rose significantly only during the oral study. Plasma free fatty acids and blood glycerol levels declined while lactate and pyruvate increased. Glucose concentration did not change during both tests. These data suggest that the administration of large quantities of alanine is capable of inducing significant alterations in levels of other amino acids and substrates as well as changing hormone levels.
The impact properties and damage tolerance and of bi-directionally reinforced fiber metal laminates

Fiber metal laminates are an advanced hybrid materials system being evaluated as a damage tolerance and light weight solution for future aircraft primary structures. This paper investigates the impact properties and damage tolerance of glass fiber reinforced aluminum laminates with cross-ply glass prepreg layers. A systematic low velocity impact testing program based on instrumented drop weight was conducted, and the characteristic impact energies, the damage area, and the permanent deflection of laminates are used to evaluate the impact performance and damage resistance. The post-impact residual tensile strength under various damage states ranging from the plastic dent, barely visible impact damage (BVID), clearly visible impact damage (CVID) up to the complete perforation was also measured and compared. Additionally, the post-impact fatigue behavior with different damage states was also explored. The results showed that both GLARE 4 and GLARE 5 laminates have better impact properties than those of 2024-T3 monolithic aluminum alloy. GLARE laminates had a longer service life than aluminum under fatigue loading after impact, and they did not show a sudden and catastrophic failure after the fatigue crack was initiated. The damage initiation, damage progression and failure modes under impact and fatigue loading were characterized and identified with microscopy, X-ray radiography, and by deply technique.
Correlation of cytogenetic and fluorescence in situ hybridization (FISH) studies in normal and gliotic brain.

In vitro tissue culturing, for karyotype analysis, may introduce artifacts confounding the cytogenetic evaluation of tissues with low baseline proliferative activity. Utilizing a panel of fluorescence in situ hybridization (FISH) probes for chromosomes 7, 8, 9, 10, 12, 17, 18, X, and Y, we compared the results of FISH analysis of non-tumorous normal (11 patients) and gliotic (10 patients) brain tissue touch preparations with those of cytogenetic evaluation performed on short-term primary cultures of the same material. We found a significant rate of apparent monosomy of chromosomes 8 and 17 by FISH analysis, with no corresponding clonal chromosomal loss detected by karyotype evaluation. These monosomy rates were significantly lower in gliotic than in normal brain tissue, and image anlaysis suggested that this apparent monosomy was due to interphase pairing of homologous centromere signals. Two distinct Y-chromosome signals were seen in 9.4% of nuclei by FISH, with 3 of 15 males displaying disomy Y rates over 15%. Disomy Y rates correlated approximately with age and clonal disomy Y was seen in the karyotype of one of these specimens. Karyotype analysis demonstrated loss of a sex chromosome in 6 specimens, while no sex chromosome nullisomy was detected by FISH. FISH is a valuable adjunct to the cytogenetic evaluation of tissues with low baseline proliferative activity. The differences in relatiave monosomy rates between normal and gliotic brain suggest that alterations in nuclear architecture and/or DNA sequence accompany the transition from normal to reactive glia.
“Direct” Calculation of Thermal Rate Constants for the F + H2 → HF + F Reaction

We present “direct” calculations of the thermal rate constant for the F + H2 reaction. The rate is obtained from the time integral of the flux−flux autocorrelation function, which is efficiently evaluated by taking advantage of the low rank of the half-Boltzmannized flux operator. Total rate constants are obtained from exact total angular momentum J ≠ 0 calculations and compared with approximate approaches for including nonzero J. The rate constants obtained for the F + H2 reaction on the new, highly accurate Stark−Werner potential energy surface are in good agreement with previous experimental results.
A Short Conserved Motif Is Required for Repressor Domain Function in the Myeloid-specific Transcription Factor CCAAT/Enhancer-binding Protein ε

CCAAT/enhancer-binding protein epsilon (C/EBPepsilon) is expressed almost exclusively in the myeloid lineage of the hematopoietic system and functions during terminal differentiation of neutrophils and macrophages, and in the regulation of cytokine gene expression in macrophages and T cells. We have undertaken a series of structure/function studies on the murine C/EBPepsilon polypeptide to investigate the mechanism by which C/EBPepsilon activates transcription. Studies with deletion mutants and fusion proteins consisting of C/EBPepsilon sequences joined to the Gal4 DNA-binding protein identified two transcriptional activation domains in C/EBPepsilon. Removal of sequences between the two activation domains or sequences between the second activation domain and the C-terminal DNA binding domain significantly increased the activity of C/EBPepsilon, suggesting the presence of two separate regulatory domains (designated RD-1epsilon and RD-2epsilon). RD-1epsilon behaved as a classic active repressor domain being capable of inhibiting adjacent activation domains irrespective of their origin and when linked to a heterologous DNA binding domain. Mutagenesis studies revealed a short motif in RD-1epsilon that appears to be a target site for protein-protein interactions and is conserved in repressor domains from C/EBPbeta, Sp3, c-Fos, and FosB. The juxtaposition of activation and repressor domains may permit C/EBPepsilon to function as a transcriptional activator or repressor at different stages of myeloid differentiation or as an inducible transcriptional activator of cytokine genes.
A 3D approximate maximum likelihood solver for localization of fish implanted with acoustic transmitters

Better understanding of fish behavior is vital for recovery of many endangered species including salmon. The Juvenile Salmon Acoustic Telemetry System (JSATS) was developed to observe the out-migratory behavior of juvenile salmonids tagged by surgical implantation of acoustic micro-transmitters and to estimate the survival when passing through dams on the Snake and Columbia Rivers. A robust three-dimensional solver was needed to accurately and efficiently estimate the time sequence of locations of fish tagged with JSATS acoustic transmitters, to describe in sufficient detail the information needed to assess the function of dam-passage design alternatives. An approximate maximum likelihood solver was developed using measurements of time difference of arrival from all hydrophones in receiving arrays on which a transmission was detected. Field experiments demonstrated that the developed solver performed significantly better in tracking efficiency and accuracy than other solvers described in the literature.
Cyclin-Dependent Kinase-2 in the Birth and Death of Cardiac Muscle Cells

The proliferative cell cycle in both vertebrates and much simpler organisms entails the transduction of mitogenic signals to cyclically expressed proteins known as cyclins and, hence, to their catalytically active targets, the cyclin-dependent protein kinases (cdks).1 2 In yeast, a single kinase, cdc28, suffices to partner with all of the cyclins, which are expressed sequentially in the G1 (cln 1/2/3), S (clb 5/6), and G2/M phases of the cycle, respectively. In mammals, by contrast, D-type cyclins in G1 partner with cdk4/6, cyclins E and A sequentially partner with cdk2 in S phase, and cyclin B interacts with cdc2 for entry into M phase. Whereas one family of cdk inhibitors is specific for cdk4/6 (the INK4 family, comprising p15, p16, p18, and p19), a second, the Cip/Kip family, has much broader activity, inhibiting cdk2 and cdc2 in addition. Activation of the cell cycle through induction of cyclin D occurs in large part by the titration of Cip/Kip proteins away from cdk2 to the cyclin D–cdk complexes. Substrates of primary importance to the actions of cdk4/6 are the retinoblastoma family of pocket proteins, whereas much less is known about the substrates for cdk2, although some have been identified.3 One source of positive feedback within this process is that phosphorylation by cdc28 and cdk2 can promote the degradation of cdk inhibitors using the ubiquitin-proteasome pathway. A second source is that cdk2, whose enzymatic activation thus depends on cdk4/6, also phosphorylates pocket proteins in sequential or processive fashion. In addition, the mitogen-induced transcription factor Myc likewise causes S-phase entry by activating cdk2 in parallel with the pocket protein pathway.4 Thus, together these positive and negative regulators form a complex and interdependent network tightly regulating the cell cycle, in which the kinase activity of …
Computer-Aided Modeling of a Rectified DC Load-Permanent Magnet Generator System with Multiple Damper Windings in the Natural Abc Frame of Reference

In this paper, a computer-aided modeling method, by which one can analyze and predict the dynamic performance of electronically rectified load-permanent magnet generator systems with multiple damping circuits is presented. Perpetual electronic switching in such systems results in a continuous change in the machine system network topologies. Hence, network modeling of such systems was done here on an instantaneous basis in the time domain. The natural abc frame of reference was used throughout. An advantage of using this approach is that it enables one to directly use readily available abc machine parameters obtained from magnetic field solutions. Thus, the inherent nonlinearities and space harmonics in the flux linkages, inductances, as well as induced emfs are fully accounted for in this modeling and analysis approach. This method was applied to a two-pole, 75 kVA, 208 V, 24000 r/ min permanent magnet generator-3 phase full wave rectifier load system, Figure (1). The resulting model was used to study the generator-load system performance. Details of developing this model are given in the paper. Accordingly, by using generalized concepts of network graph theory in conjunction with hybrid matrix formulation of nonlinear networks, see references [5] and [9] in the paper, the state equations associated with this system were automatically formulated and continuously updated in a computer-aided network solution program.
STRUCTURAL RESPONSES OF TRANSIT BUSES: IMPACT OF WHEELCHAIR LOADS

The structural responses of typical transit buses with and without wheelchair loads and the changes in these responses from one bus design to the next were investigated. To this end, finite-element computer models, with and without wheelchairs, wheelchair restraints, and wheelchair lifts, were developed for two 7.6-m transit buses designed in 1989 and 1992. These models were each analyzed under bus deceleration with seats attached to the bus floor only, and with seats attached to the bus sidewall and floor. With respect to the structural responses of these typical transit buses to bus deceleration it was concluded that (a) maximum member stresses in models with wheelchair loads versus models without wheelchair loads tended to increase in the 1989 bus models and decrease in the 1992 bus models and (b) small to moderate changes in the number, size, and location of structural members from one bus design to the next can have a substantial impact on the maximum member stresses.
Glutamate-modulating drugs as novel pharmacotherapeutic agents in the treatment of obsessive-compulsive disorder.

Obsessive-compulsive disorder (OCD) is a common psychiatric disorder that produces significant morbidity. The introduction of serotonin reuptake inhibitors in the 1980s represented an important advance in the treatment of OCD. However, few patients show complete remission of their symptoms, and some patients show minimal improvement with existing treatments. We review current treatment strategies and initial data supporting the efficacy of glutamate modulating agents as a novel class of Pharmaceuticals for the treatment of OCD. Functional neuroimaging studies repeatedly reported metabolic hyperactivity in the cortico-striato-thalamo-cortical circuitry in patients with OCD. Recent magnetic resonance spectroscopy studies provide evidence of elevated glutamate levels in several brain regions in patients suffering from OCD. These findings raised the possibility that agents that reduce glutamate hyperactivity or its consequences in the CNS might be efficacious as novel therapeutic interventions. Indeed, initial evidence from our group suggests that the antiglutamatergic agent riluzole (Rilutek), which was developed for the treatment of amyotrophic lateral sclerosis, is effective in treatment-resistant OCD. Case reports suggest that other agents that modulate glutamatergic activity may likewise be effective. This new application of glutamate modulating agents holds promise for the treatment of this disabling and often inadequately treated disease.
Galanin peptide levels in hippocampus and cortex of galanin-overexpressing transgenic mice evaluated for cognitive performance.

Galanin-overexpressing transgenic mice (GAL-tg) generated on a dopamine β-hydroxylase promoter were previously shown to express high levels of galanin mRNA in the locus coeruleus, and to perform poorly on challenging cognitive tasks. The present study employed radioimmunoassay to quantitate the level of galanin peptide overexpression in two brain regions relevant to learning and memory, the hippocampus and cerebral cortex. Approximately 4-fold higher levels of galanin were detected in the hippocampus of GAL-tg as compared to WT. Approximately 10-fold higher levels of galanin were detected in the frontal cortex of GAL-tg as compared to WT. A second cohort of GAL-tg and WT again showed high levels of galanin overexpression in GAL-tg as compared to WT in both brain regions. Correlation analyses were conducted between galanin peptide concentrations and behavioral scores on four learning and memory tasks: the Morris water maze, social transmission of food preference, standard delay fear conditioning, and trace fear conditioning. While some significant correlations were detected, neither hippocampal nor cortical galanin levels in the two cohorts of GAL-tg consistently correlated with performance across these diverse cognitive tasks. Several interpretations of these findings are discussed, including the possibility that a threshold level of galanin overexpression is sufficient to impair performance on learning and memory tasks in mice.
Startle modulation in autism: Positive affective stimuli enhance startle response

Behavioral evidence suggests that emotion processing deficits in individuals with autism spectrum disorders (ASD) may occur at the level of basic (early, rapid, automatic) affective processes. Consistently, neurological evidence indicates that key brain areas associated with basic affective processing are atypical in ASD. The current study sought to better specify these deficits by comparing different components of basic affective processing in 14 adolescents and adults with ASD and 14 typical controls matched for age and verbal ability. Participants viewed affective pictures, and their responses were assessed with (i) affective eyeblink startle modulation, an indicator of the brain's aversive motivational system; (ii) facial electromyography, an online indicator of implicit valence appraisal; and (iii) self-report, an indicator of overt valence appraisal. The results show that in contrast to the typical pattern, in which exposure to negative stimuli increases startle whereas exposure to positive stimuli decreases startle, individuals with ASD showed startle potentiation to both positive and negative stimuli. Atypical potentiation during positive stimuli occurred despite individuals with ASD demonstrating appropriate implicit valence appraisals, reflected in their facial EMG responses, and appropriate overt appraisals, reflected in their self-reported ratings of the stimuli. Potentiation of startle to both positive and negative stimuli suggests a disruption in basic affective processes in ASD at the level of the early motivational response. This atypical pattern of responses has implications for understanding social and emotion deficits in ASD and calls for further investigation of basic affective processes.
Development of an Analytical SparkJet Model

A variety of active flow control (AFC) methods have been successfully applied to low speed flows; however, AFC techniques available for high-speed, supersonic applications are very limited. Under the Air Force Office of Scientific Research sponsorship, The Johns Hopkins University Applied Physics Laboratory is investigating a device intended for highspeed flow control called the SparkJet actuator, which manipulates high-speed flows without active mechanical components. Actuator characterization to date has included computational and experimental techniques, including parametric studies and flow visualization over a variety of operating conditions. This paper focuses on the development of an analytical model accompanied by experimental acquisition of the pressure inside the SparkJet cavity. Previous experimental efforts included the use of high-resolution particle image velocimetry and digital speckle tomography to measure the plume velocities and temperature distribution, respectively, in the core of the SparkJet plume. While these tests gave high-resolution results, the results were incomplete and the high velocity core remains difficult to quantify experimentally. Therefore, attention turned to internal chamber pressure measurements to help validate computational fluid dynamics and analytical models. The analytical model presented previously has been expanded to include the unchoked portion of the discharge and preliminary model development of the refresh stage has begun. Experimental testing includes variations in electrode configuration and power supply design intended to improve SparkJet performance. This preliminary characterization study resulted in an actuator design 3.5 times more efficient as previous actuator designs. As a result of this work, a maximum efficiency factor of 35% has been demonstrated so far for the SparkJet actuator based on the experimental peak pressure inside the SparkJet cavity. Future work will include improving SparkJet efficiency further, expanding the model to predict high-frequency actuation performance of a single actuator and testing various SparkJet configurations to enhance the model validation and understand the model limitations.
Leukotriene C4 modulation of muscarinic K+ current activation in bullfrog atrial myocytes.

The effects of leukotriene C4 (LTC4) on activation of muscarinic acetylcholine receptor (mAChR)-stimulated, inwardly rectifying K+ current (IK[ACh]) were examined in single bullfrog atrial myocytes using the whole-cell patch clamp technique. LTC4 produced a reversible, concentration-dependent increase in steady-state, guanosine-gamma-thiotriphosphate (GTP gamma S)-activated IK[ACh], with a K0.5 of 3.1 microM. LTC4 also increased the rate of GTP gamma S-mediated IK[ACh] activation, both in the absence and presence of 1 nM ACh, with comparable K0.5 values of 4.7 microM under basal conditions and 4.9 microM in the presence of 1 nM ACh. LTC4 did not alter the relative affinities of the G protein, Gk, for GTP gamma S and GTP. We hypothesize that all of the effects of LTC4 on the kinetics of Gk-mediated IK[ACh] activation are produced at a common site with a K0.5 of 3-5 microM. The effects of LTC4 on IK[ACh] activation are fully reversible in the presence of GTP gamma S. Under physiological conditions (i.e., intracellular GTP), 10 microM LTC4 increased the ACh-activated peak IK[ACh]. Inhibitors of cellular LTC4 production, including 5,8,11,14-eicosatetraynoic acid, baicalein, cinnamyl-3,4-dihydroxy-alpha-cyanocinnamate, and alpha-pentyl-4-(2-quinolinylmethoxy)-benzene methanol, greatly attenuated ACh-dependent IK[ACh] activation, preventing activation of peak, and producing a lower steady-state IK[ACh] (when compared with the control response in the same cell). Addition of exogenous LTC4 was able to overcome the effects of LTC4 synthesis inhibitors, restoring both the peak and steady-state IK[ACh] responses. Although the mechanism of LTC4-mediated modulation of IK[ACh] activation is not known, our results suggest that endogenously produced lipoxygenase metabolites of arachidonic acid, specifically LTC4, are involved in the physiological process of IK[ACh] activation.
Peptide backbone reconstruction using dead-end elimination and a knowledge-based forcefield.

A novel, yet simple and automated, protocol for reconstruction of complete peptide backbones from Cα coordinates only is described, validated, and benchmarked. The described method collates a set of possible backbone conformations for each set of residue triads from a structural library derived from the PDB. The optimal permutation of these three residue segments of backbone conformations is determined using the dead-end elimination (DEE) algorithm. Putative conformations are evaluated using a pairwise-additive knowledge-based forcefield term and a fragment overlap term. The protocol described in this report is able to restore the full backbone coordinates to within 0.2–0.6 A of the actual crystal structure from Cα coordinates only. In addition, it is insensitive to errors in the input Cα coordinates with RMSDs of 3.0 A, and this is illustrated through application to deliberately distorted Cα traces. The entire process, as described, is rapid, requiring of the order of a few minutes for a typical protein on a typical desktop PC. Approximations enable this to be reduced to a few seconds, although this is at the expense of prediction accuracy. This compares very favorably to previously published methods, being sufficiently fast for general use and being one of the most accurate methods. Because the method is not restricted to the reconstruction from only Cα coordinates, reconstruction based on Cβ coordinates is also demonstrated. © 2003 Wiley Periodicals, Inc. J Comput Chem 25: 16–27, 2004
Luther and the Ascent of Jacob's Ladder

On the west front of Bath Abbey there are carved two stone ladders stretching from heaven to earth on which twelve angels are climbing, six on each ladder. A tourist who sees the west front of the abbey for the first time is told that the carvings represent the dream of Oliver King, Bishop of Bath and Wells under Henry VII and his former chief secretary. The bishop had a nocturnal vision of angels climbing ladders to heaven. As he stood before the ladders in amazement, he heard voices saying that an olive should establish the crown and that the king should restore the church. He took the reference to olives and kings to be an allusion to his own name and concluded that he, Oliver King, should support the Tudor monarchy and rebuild the ruined abbey at Bath.
A Complete Species-Level Phylogeny of the Grackles (Quiscalus spp.), Including the Extinct Slender-Billed Grackle, Inferred from Mitochondrial DNA

Abstract The grackles (Quiscalus spp.), together with their sister genus Euphagus, compose a clade within the New World blackbirds (Icteridae). We used gene sequences of cytochrome b and NADH dehydrogenase subunit 2 (ND2) to reconstruct relationships within this group. A primary concern was determining the phylogenetic position and genetic distinctiveness of the extinct Slender-billed Grackle (Q. palustris)—a poorly known endemic of the Lerma Basin and the ancient lakes of the Valley of Mexico, last collected and recorded in 1910—and of the Nicaraguan Grackle (Q. nicaraguensis), which is likewise unusual among grackles for its restricted geographic range. Our analysis differs from previous efforts by inclusion of these taxa along with all other recognized grackle species, intraspecific sampling of Greater Antillean (Q. niger), Carib (Q. lugubris), and Great-tailed (Q. mexicanus) Grackles, and inclusion of additional sequence data. The recovered phylogeny reveals Slender-billed Grackle to be most closely r...
Semantics-oriented low power architecture

Innovations in the microarchitecture and prominent advances in the semiconductor process technology enable sophisticated and powerful microprocessors. However, they also lead to increased power consumption. The main contribution of the thesis is the demonstration of Semantics-Oriented Low Power Architecture techniques that use the semantics of memory references and variables used in an application program to reduce the power consumption in the memory sub-system of a microprocessor. The Semantic-Aware Multilateral Partitioning (SAM) technique reduces the cache and TLB power consumption by decoupling the data TLB lookups and the data cache accesses, based on the semantic regions defined by the programming languages and the software convention, into discrete reference sub-streams, namely, stack, global static, and heap. To reduce the power consumed by the snoops in Chip Multiprocessor, we propose a hardware technique called Selective Snoop Probe (SSP) and a compiler-based hardware supported technique called Essential Snoop Probe (ESP) that use the properties of the program variables. By selectively sending the snoop probes, the SSP and ESP techniques relax the conservative nature of the cache coherency protocol and its implementation to reduce power and improve performance.
Cytochrome c551 and the Cytochrome c Maturation Pathway Affect Virulence Gene Expression in Bacillus cereus ATCC 14579

Loss of the cytochrome c maturation system in Bacillus cereus results in increased transcription of the major enterotoxin genes nhe, hbl, and cytK and the virulence regulator plcR. Increased virulence factor production occurs at 37°C under aerobic conditions, similar to previous findings in Bacillus anthracis. Unlike B. anthracis, much of the increased virulence gene expression can be attributed to loss of only c551, one of the two small c-type cytochromes. Additional virulence factor expression occurs with loss of resBC, encoding cytochrome c maturation proteins, independently of the presence of the c-type cytochrome genes. Hemolytic activity of strains missing either cccB or resBC is increased relative to that in the parental strain, while sporulation efficiency is unaffected in the mutants. Increased virulence gene expression in the ΔcccB and ΔresBC mutants occurs only in the presence of an intact plcR gene, indicating that this process is PlcR dependent. These findings suggest a new mode of regulation of B. cereus virulence and reveal intriguing similarities and differences in virulence regulation between B. cereus and B. anthracis.
The evolutionary capacity of protein structures

In nature, one finds large collections of different protein sequences exhibiting roughly the same three-dimensional structure, and this observation underpins the study of structural protein families. In studying such families at a global level, a natural question to ask is how close to "optimal" the native sequences are in terms of their energy. We therefore define and compute the evolutionary capacity of a protein structure as the total number of sequences whose energy in the structure is below that of the native sequence. An important aspect of our definition is that we consider the space of all possible protein sequences, i.e. the exponentially large set of all strings over the 20-letter amino acid alphabet, rather than just the set of sequences found in nature.In order to make our approach computationally feasible, we develop randomized algorithms that perform approximate enumeration in sequence space with provable performance guarantees. We draw on the area of rapidly mixing Markov chains, by exhibiting a connection between the evolutionary capacity of proteins and the number of feasible solutions to the Knapsack problem. This connection allows us to design an algorithm for approximating the evolutionary capacity, extending a recent result of Morris and Sinclair on the Knapsack problem. We present computational experiments that show the method to be effective in practice on large collections of protein structures. In addition, we show how to use approximations to the evolutionary capacity to compute a statistical mechanics notion of "evolutionary temperature" on sequence space.
Field and laboratory evaluations of transgenic cottons expressing one or two Bacillus thuringiensis var. kurstaki Berliner proteins for management of noctuid (Lepidoptera) pests.

Abstract Field studies were conducted from 1999 to 2001 to evaluate the efficacy of the transgenic cotton, Gossypium hirsutum (L.), genotype, Bollgard II (Monsanto 15985), which expresses two Bacillus thuringiensis Berliner (Bt) proteins (Cry1Ac + Cry2Ab) that are active against lepidopterous pests. Bollgard II was compared with Bollgard (DP50B), which expresses only one Bt protein (Cry1Ac), and, in all tests, the conventional variety, DP50, was used as a non-Bt control. Larval populations of the bollworm, Helicoverpa zea (Boddie), and the soybean looper, Pseudoplusia includens (Walker), were significantly lower in Bollgard II than in Bollgard and conventional cotton, and the proportion of fruit damaged by H. zea was also lower. Fall armyworm, Spodoptera frugiperda (J. E. Smith), populations were lower in Bollgard II than in Bollgard, although not significantly. Field tests were supplemented with laboratory bioassays in 2001 to compare mortality of S. frugiperda, and beet armyworms, Spodoptera exigua (Hub...
A Comparative Analysis of How the Framing of the Jus Soli Doctrine Affects Immigrant Inclusion into a National Identity

The migration of immigrant populations continues to be a pressing legal, social, and political issue. In this paper, I expand upon my previous findings on how the operation of the doctrine jus soli affects immigrant minority inclusion into a national identity by situating the country of Chile into the analysis of the United States and the Dominican Republic. The constitution of Chile, as with the Dominican Republic, provides for birthright citizenship to any person except those born to individuals “that are of transit” in the country. However, the Chilean constitution allows for the person to opt for Chilean nationality. Thus, although the Chilean constitution limits the scope of the jus soli principle in a manner that has the potential to exclude immigrant minorities from Chilean national identity, it’s limiting clause is qualified in such a manner to provide for a window of opportunity for immigrant minorities to be included in Chilean nationality.
A Novel Method of Determining the Functional Effects of a Minor Genetic Modification of a Protein.

Contraction of muscles results from the ATP-coupled cyclic interactions of the myosin cross-bridges with actin filaments. Macroscopic parameters of contraction, such as maximum tension, speed of shortening or ATPase activity, are unlikely to reveal differences between the Wild Type and mutated proteins when the level of transgenic protein expression is low. This is because macroscopic measurements are made on whole organs containing trillions of actin and myosin molecules. An average of the information collected from such a large assembly is bound to conceal any differences imposed by a small fraction of mutated molecules. To circumvent the averaging problem, the measurements were done on isolated ventricular myofibril in which thin filaments were sparsely labeled with a fluorescent dye. We isolated a single myofibril from a ventricle, oriented it vertically (to be able measure the orientation), and labeled 1 in 100,000 actin monomers with a fluorescent dye. We observed the fluorescence from a small confocal volume containing ~3 actin molecules. During the contraction of a ventricle actin constantly changes orientation (i.e. the transition moment of rigidly attached fluorophore fluctuates in time) because it is repetitively being “kicked” by myosin cross-bridges. An autocorrelation functions of these fluctuations are remarkably sensitive to the mutation of myosin. We examined the effects of Alanine to Threonine (A13T) mutation in the myosin regulatory light chain shown by population studies to cause hypertrophic cardiomyopathy. This is an appropriate example, because mutation is expressed at only 10% in the ventricles of transgenic mice. Autocorrelation functions were either “Standard” (decaying monotonically in time) or “Non-standard” (decaying irregularly). The sparse labeling of actin also allowed the measurement of the spatial distribution of actin molecules. Such distribution reflects the interaction of actin with myosin cross-bridges and is also remarkably sensitive to myosin mutation. The result showed that the A13T mutation caused 9% autocorrelation functions and 9% of spatial distributions of actin to be non-standard, while the remaining 91% were standard, suggesting that the nonstandard performances were executed by the mutated myosin heads and that the standard performances were executed by non-mutated myosin heads. We conclude that the method explored in this study