cssi/SciSciGPT-SciSciNet huggingface dataset:
The Art of Dissecting the Function of a Potassium Channel

The essential function of potassium channels is to selectively facilitate the passage of K + ions across the cell membrane by lowering the energy barrier that opposes this process. In this issue of Neuron , Chatelain et al. report the results from an elegant study that sheds new light on the microscopic factors that modulate the function of these important membrane channels.
Nonlinear inverse model for velocity estimation from an image sequence

[1] Velocity estimation from an image sequence is one of the most challenging inverse problems in computer vision, geosciences, and remote sensing applications. In this paper a nonlinear model has been created for estimating motion field under the constraint of conservation of intensity. A linear differential form of heat or optical flow equation is replaced by a nonlinear temporal integral form of the intensity conservation constraint equation. Iterative equations with Gauss-Newton and Levenberg-Marguardt algorithms are formulated based on the nonlinear equations, velocity field modeling, and a nonlinear least squares model. An algorithm with progressive relaxation of the overconstraint to improve the performance of the velocity estimation is also proposed. The new estimator is benchmarked using a numerical simulation model. Both angular and magnitude error measurements based on the synthetic surface heat flow from the numerical model demonstrate that the performance of the new approach with the nonlinear model is much better than the results of using a linear model of heat or optical flow equation. Four sequences of NOAA Advanced Very High Resolution Radiometer (AVHRR) images taken in the New York Bight fields is also used to demonstrate the performance of the nonlinear inverse model, and the estimated velocity fields are compared with those measured with the Coastal Ocean Dynamics Radar array. The experimental results indicate that the nonlinear inverse model provides significant improvement over the linear inverse model for real AVHRR data sets.
The Market in Defaulted Bonds and Bank Loans

There has been remarkable growth in the distressed debt market in the United States in the past 20 years. Data presented here indicate why distressed debt (vulture capital) investing is perhaps the fastest growing sector in the hedge fund universe and why it has also become of interest to the private equity sector. Returns on distressed assets, including the equity of firms emerging from Chapter 11, were spectacular in 2003, excellent in 2004, and, for many hedge funds, also good in 2005. The same was true for investment in a long-only strategy of defaulted bonds and loans in 2003-2004. Investors have many more investment options than strictly defaulted securities, and are increasingly following diverse strategies.
The Dwell Time of Indwelling Ureteral Stents—The Clock is Ticking But When Should We Set the Alarm?

STENT encrustation is a critical concern that often directs the duration of stenting. Previous studies have suggested that 48% of stents will be encrusted even if removed before the 3-month mark is reached. In addition, longer stent durations lead to greater patient discomfort. Evaluating conditions at high risk for encrustation (such as pregnancy) or conditions at low risk might help not only tailor the recommended dwell times but also elucidate the mechanisms of stent encrustation. One group of patients who seem to tolerate ureteral stents well in terms of symptoms and encrustation are those with malignant ureteral obstruction. In this issue of The Journal Izumi et al (page 556) reported that despite using relatively small ureteral stents (4.8 to 6Fr) the median indwell time was almost 8 months. Patients with gynecologic and urological cancers were successfully treated for longer times than those stented for other malignancies. Unfortunately stone formers do not fare so well. Also in this issue Weedin et al (page 542) evaluated the impact of proximal ureteral stone burden on the management strategy for forgotten stents. Of their cohort 89% was stented for stone disease. Although mean stent duration was more than 2 years, 94% of patients could still be treated endoscopically. They demonstrated that computerized tomography was more accurate to stage the amount of proximal stent encrustation, a critical prognostic variable for the need for multiple procedures and the risk of surgical complications. Interestingly the duration of stenting did not correlate with the need for multiple surgeries, suggesting that other variables are more impor-
Illnesses Causing Dementia in the Very Elderly

Understanding the twin phenomena of aging and the dementing illnesses common in old age is a challenge to clinicians and investigators. Alzheimer's disease has now garnered the most attention as the predominant cause of dementia. Not long ago, a major effort of medical and lay education was to counter the myth that dementia -- or a global decline in intellectual ability sufficient to produce functional disability -- was a normal accompaniment of aging1. Another myth that stood for seven decades after Alzheimer's work2 was that the gradual narrowing of cerebral blood vessels somehow damaged the neurons and caused dementia, . . .
An acute rise in intraluminal pressure shifts the mediator of flow-mediated dilation from nitric oxide to hydrogen peroxide in human arterioles

Endothelial nitric oxide (NO) is the primary mediator of flow-mediated dilation (FMD) in human adipose microvessels. Impaired NO-mediated vasodilation occurs after acute and chronic hypertension, p...
Event Trigger for the MARK-III Detector at SPEAR

The Mark-III is a third generation solenoidal magnetic detector designed for investigation of the production and decay of particles at 3 to 5 GeV center of mass energy. It is located at the SPEAR electron-position storage ring at Stanford University. Information from events consists of signal times and areas from each of the elements of the detector: the tracking drift chamber, time-of-flight scintillation counters, an electromagnetic shower calorimeter, and single-wire proportional tube muon detectors. The function of the trigger is to select interesting events in a bias free manner while efficiently rejecting backgrounds. It does this by finding tracks made by charged particles coming from the interaction region, where the electrons and positrons collide.
Phosphate application to firing range soils for Pb immobilization: The unclear role of phosphate

Phosphate treatment has emerged as a widely accepted approach to immobilize Pb in contaminated soils and waste media, relying on the formation of the highly insoluble mineral pyromorphite as solubility-controlling phase for Pb. As such, phosphate treatment has been proposed as a Best Management Practice (BMP) for firing ranges where Pb occurs in its metallic forms and several other phases (carbonates, oxides). While pyromorphite thermodynamically has the potential to control Pb solubility at low levels, its formation is kinetically controlled by pH, the solubility of the phosphate source, and the solubility of Pb species. Treatability studies have shown that excess quantities of soluble and acidic phosphate sources, such as phosphoric acid, are necessary for successful in situ treatment. Even under these conditions, Extended X-ray Absorption Fine Structure (EXAFS), the only reliable method to identify and quantify Pb speciation, showed that Pb conversion to pyromorphite in in situ treated soils was less than 45% after 32 months. Furthermore, the use of lime (CaO) to restore soil pH in acidified soil treatments inhibited further conversion. Additionally, phosphate treatment is known to reduce bioavailability through pyromorphite formation in the intestinal tract, and the phytoaccumulation of Pb; both desirable effects for Pb-impacted areas. Given the costs of phosphate treatment, the use of biogenic phosphate sources, such as bone meal, may be a more environmentally sustainable approach toward this end. In the many studies focusing on phosphate treatment, the attendant P leaching and eutrophication have been largely overlooked, along with other issues such as the enhanced leaching of oxyanionic contaminants, such as Se, As and W. The success and sustainability of applying phosphate as a BMP in firing range soils therefore remain questionable.
Identification of interspecific hybrids among domesticated apple and its wild relatives

Potential interspecific hybrids are usually identified in natural populations by their proximity to interbreeding species or their intermediate phenotypes; hybridization can then be confirmed by comparing the genetic makeup of putative hybrids to pure species. In contrast, detecting interspecific hybridization and misclassifications in ex situ collections can be difficult because fine-scale geographic locations and species-specific phenotypic data are generally unavailable. Thus, there is little a priori information available to suggest which individuals might be hybrids. Instead, hybrids or misclassified individuals must be identified based on molecular data via population assignment and admixture detection programs. We have applied a variety of population assignment and admixture detection programs to over 400 samples of four closely related Malus species held in the US Department of Agriculture–Agricultural Research Service National Plant Germplasm System that were genotyped at 19 simple sequence repeat loci. Our findings indicate that over 10 % of the samples of the wild species Malus sieversii and Malus orientalis and nearly 20 % of the samples of the wild species Malus sylvestris may be admixed or misclassified. The percentage of admixed or misclassified samples of the domesticated species, Malus × domestica, was much lower, at <5 %. These findings provide an illustration of how to detect hybridization and misclassification in ex situ collections using molecular data and, ultimately, should help to maximize the utility of the collections. In addition, the presence of wild-collected samples that show admixture with domesticated apple suggests that gene flow may be occurring from the crop into natural populations of the wild species.
An analysis of shear waves generated by the Sterling explosion

[1] We show that the near-field shear waves from the decoupled explosion Sterling were likely caused by the cavity shape, which was approximately spherical except for a flat floor due to melted and recrystallized salt. We model the impact of the explosion shock wave on the cavity walls using a two-dimensional (2-D) Eulerian finite difference code that simulates the evolution of the air shock in the cavity coupled with 2-D Lagrangian finite difference code that simulates the nonlinear region outside the cavity. Calculated shear waves generated by the asymmetric impact of the shock wave on the cavity walls match the observed initial shear wave amplitudes and radiation pattern. The observations also have substantial P and S coda, which are not reproduced by the calculations. Similarity of coda waveforms with distance indicates that their source is at or very near the cavity. Longer time modeling of the air shock evolution appears to produce a more realistic source function and provide a better match to the coda and indicates that the coda are caused by air reverberations between the top and bottom of the cavity. We assess the likelihood that fractures created by the tamped explosion that formed the cavity Salmon were reopened by Sterling. Modeling of hydrofracture propagation driven by the Sterling explosion, by coupling stress wave dynamics in rock with fluid mechanics in the fractures, shows that the cavity pressure is insufficient to overcome the overburden to propagate fractures into rock, except for the area immediately below the explosion on the cavity floor.
A fuzzy-AHP approach to prioritization of CS attributes in target planning for automotive product development

Understanding customer requirements and incorporating them into the conceptual vehicle design is the first step of automotive product development (PD). However, lack of quantitative data and undefined relationships between the attributes makes it difficult to develop a quantitative model for analyzing subjective customer satisfaction (CS) attributes. While researchers and practitioners have accomplished a significant success in terms of developing tool such as quality function deployment (QFD) to capture the voice of customers, and mathematical models for selecting engineering design alternatives, there is limited precedence in terms of prior works on customer satisfaction driven quality improvement target planning and prioritization of customer satisfaction attributes for target planning. This paper presents a fuzzy set theory based analytic hierarchy process (fuzzy-AHP) framework for prioritizing CS attributes in target planning. Furthermore, unlike prior QFD papers, we consider a broad range of strategic and tactical factors for determining the weights. These weights are then incorporated into target planning by identifying the gap in the current CS level. A case example from automotive industry is presented to demonstrate efficacy of the proposed methodology. The framework has been implemented on MS Excel(R) so that the industry can easily adopt it with limited amount of training and at no additional software cost.
Novel regulators of vitamin D action and metabolism: Lessons learned at the Los Angeles zoo.

We undertook an investigation of an outbreak of rachitic bone disease in the Emperor Tamarin New World primate colony at the Los Angeles Zoo in the mid-1980s. The disease phenotype resembled that observed in humans with an inactivating mutation of the vitamin D receptor (VDR), hypocalcemia, high 1,25-dihydroxyvitamin D (1,25-(OH)2D) levels, and rickets in rapidly growing adolescent primates. In contrast to the human disease, the New World primate VDR was functionally normal in all respects. The proximate cause of vitamin D hormone resistance in New World primates was determined to be the constitutive overexpression of a heterogeneous nuclear ribonucleoprotein in the A family which we coined the vitamin D response element binding protein (VDRE-BP). VDRE-BP competed in trans with the VDR-retinoid X receptor (RXR) for binding to the vitamin D response element. VDRE-BP-legislated resistance to 1,25-(OH)2D was antagonized (i.e., compensated) by another set of constitutively overexpressed proteins, the hsp-70-related intracellular vitamin D binding proteins (IDBPs). IDBPs, present but expressed at much lower levels in Old World primates including man, exhibited a high capacity for 25-hydroxylated vitamin D metabolites and functioned to traffic vitamin Ds to specific intracellular destinations to promote their action and metabolism. J. Cell. Biochem. 88: 308–314, 2003. © 2002 Wiley-Liss, Inc.
Pose and motion estimation using dual quaternion-based extended Kalman filtering

A solution to the remote three-dimensional (3-D) measurement problem is presented for a dynamic system given a sequence of two-dimensional (2-D) intensity images of a moving object. The 3-D transformation is modeled as a nonlinear stochastic system with the state estimate providing the six-degree-of-freedom motion and position values as well as structure. The stochastic model uses the iterated extended Kalman filter (IEKF) as a nonlinear estimator and a screw representation of the 3-D transformation based on dual quaternions. Dual quaternions, whose elements are dual numbers, provide a means to represent both rotation and translation in a unified notation. Linear object features, represented as dual vectors, are transformed using the dual quaternion transformation and are then projected to linear features in the image plane. The method has been implemented and tested with both simulated and actual experimental data. Simulation results are provided, along with comparisons to a point-based IEKF method using rotation and translation, to show the relative advantages of this method. Experimental results from testing using a camera mounted on the end effector of a robot arm are also given.
Effort continues to double budget at several science agencies

The Bush Administration has proposed continuing last year's American Competitiveness Initiative (ACI) in the rollout of the $2.9 trillion Fiscal Year (FY) 2008 U.S. federal budget request, released on 5 February. Over a 10-year period, ACI would double the cumulative budgets of the U.S. National Science Foundation, the U.S. Department of Energy Office of Science, and the U.S. National Institute of Standards and Technology ‘core’intramural research and facilities. The initiative got off to an uneven start last year, however. Although the U.S. Congress passed FY2007 budgets for defense and homeland security, since 1 October 2006 all other departments and agencies have been operating under a series of continuing resolutions. These resolutions provide funding at the lowest of the levels set in either of the appropriations bills passed by the House of Representatives or the Senate or the amount provided in FY2006.
Thermodynamics of DNA branching.

Abstract Branched DNA molecules arise transiently as intermediates in genetic recombination or on extrusion of cruciforms from covalent circular DNA duplexes that contain palindromic sequences. The free energy of these structures relative to normal DNA duplexes is of interest both physically and biologically. Oligonucleotide complexes that can form stable branched structures, DNA junctions, have made it possible to model normally unstable branched states of DNA such as Holliday recombinational intermediates. We present here an evaluation of the free energy of creating four-arm branch points in duplex DNA, using a system of two complementary junctions and four DNA duplexes formed from different combinations of the same set of eight 16-mer strands. The thermodynamics of formation of each branched structure from the matching pair of intact duplexes have been estimated in two experiments. In the first, labeled strands are allowed to partition between duplexes and junctions in a competition assay on polyacrylamide gels. In the second, the heats of forming branched or linear molecules from the component strands have been determined by titration microcalorimetry at several temperatures. Taken together these measurements allow us to determine the standard thermodynamic parameters for the process of creating a branch in an otherwise normal DNA duplex. The free energy for reacting two 16-mer duplexes to yield a four-arm junction in which the branch site is incapable of migrating is +1.1(±0.4) kcal mol −1 (at 18 °C, 10 m m -Mg 2+ ). Analysis of the distribution of duplex and tetramer products by electrophoresis confirms that the free energy difference between the four duplexes and two junctions is small at this temperature. The associated enthalpy change at 18 °C is +27.1(±1.3) kcal mol −1 , while the entropy is +89 (±30) cal K −1 mol −1 . The free energy for branching is temperature dependent, with a large unfavorable enthalpy change compensated by a favorable entropy term. Since forming one four-stranded complex from two duplexes should be an entropically unfavorable process, branch formation is likely to be accompanied by significant changes in hydration and ion binding. A significant apparent ΔC p is also observed for the formation of one mole of junction, +0.97(±0.05) kcal deg −1 mol −1 .
Cox-2 gene expression in chemically induced skin papillomas cannot predict subsequent tumor fate

Elevated cyclooxygenase-2 (COX-2) expression is observed in a variety of premalignant neoplastic tissues, suggesting COX-2 expression might serve as a potential indicator of subsequent tumor development. However, it has not been possible to compare the relationship between Cox-2 gene expression in premalignant lesions and their subsequent fate, because conventional studies require tissue destruction for analysis of gene expression. To monitor COX-2 expression non-invasively during tumor development, we created a Cox-2 luciferase knock-in mouse, Cox-2luc, in which the firefly luciferase coding region replaces the Cox-2 coding region. Luciferase activity was non-invasively, quantitatively and repeatedly monitored in Cox-2luc/+ mice subjected to DMBA/TPA multistage skin tumor induction. Luciferase activity is significantly higher in all papillomas than in surrounding skin. However, the magnitude of Cox-2 promoter-driven luciferase activity in small papillomas cannot predict subsequent papilloma regression or growth. Elevated Cox-2 promoter-driven luciferase signal can be detected when papillomas first become visible, but not before this time.
Ultrastructural differences between smooth and thorny gonadotropin-releasing hormone neurons.

Abstract It has been suggested that gonadotropin-releasing hormone neurons with irregular contours receive more synaptic input than do those with smooth contours. To test this hypothesis, a morphometric analysis of gonadotropin-releasing hormone neurons of differing shapes was made. Male Sprague-Dawley rats were perfused and 40-μm tissue sections from the preoptic area were treated for the demonstration of gonadotropin-releasing hormone immunoreactivity, using the avidin-biotin horseradish peroxidase method with 3,3'-diaminobenzidine as the chromogen. Gonadotropin-releasing hormone neurons with either a smooth or a highly irregular outline, sampled at three depths ultrastructurally, were compared for density of synaptic innervation and for relative content of various subcellular organelles. Point counting stereology comparisons of five gonadotropin-releasing hormone neurons of the two shapes in four rats revealed that smooth neurons contained less cytoplasm than “thorny” neurons, but the size of their nuclei was the same. There were more and larger nucleoli in smooth cells. Thorny neurons contained more Golgi apparatus and more mitochondria, but the amount of rough endoplasmic reticulum was the same in neurons of the two morphological types. There was no difference in the incidence of synapses or in the density of synaptic input as measured per unit of neuronal membrane in smooth and thorny gonadotropin-releasing hormone neurons. These results suggest that smooth-contoured gonadotropin-releasing hormone neurons may be more actively transcribing a message while thorny neurons are more actively engaged in peptide processing and packaging. In that the density of synaptic input was the same, these apparent functional differences among gonadotropin-releasing hormone neurons of differing shapes may be independent of synaptic influences; but this must be tested by chemical characterization of the synapses.
Cigarette smoking and ethane exhalation in humans.

The time course of exhaled ethane gas was determined in the alveolar expirate of healthy, fasting smokers and nonsmokers after smoking a cigarette. Baseline ethane was measured by gas chromatography and corrected for background ethane after a 2-min washout using purified air. Ethane was measured immediately after smoking and hourly thereafter. Ethane was highest immediately after smoking, reflecting ethane in cigarette smoke. An exponential decline of ethane in smokers returned ethane to baseline within 3 h. Ethane in nonsmokers also peaked immediately after smoking but returned to baseline by 1 h. Ethane from smokers, measured 3 h after the last cigarette, was compared with ethane from healthy ex-smokers and nonsmokers. Mean (+/- SEM) baseline ethane in smokers was 2.90 +/- 0.52 pmol/min/kg, 1.55 +/- 0.36 pmol/min/kg in ex-smokers and 1.11 +/- 0.26 pmol/min/kg in nonsmokers (p < 0.05). Ethane in two smokers measured before and after a week of oral beta carotene supplementation (60 mg/d) fell by 80 and 35...
2-DOF contact location display for manipulating virtual objects

A novel, low inertia, two degree-of-freedom (2-DOF) contact location display (CLD) device has been designed, prototyped, and tested. This device positions a small spherical contactor beneath the user's fingerpad at the point of contact between the finger and a virtual surface. Kinesthetic forces are provided by a custom haptic device attached to the CLD. The contactor is remotely driven by push-pull wires to reduce the effective inertia of the device at the user's fingertip; however, this design results in significant mechanical backlash. This backlash is characterized and partially compensated for in software. An experiment was used to evaluate several methods of rendering tactile feedback, each using a different method of prepositioning the contactor. The results show no statistical performance differences between rendering conditions. However, a post-experiment survey shows that participants perceived contact location + kinesthetic feedback as more realistic than pure kinesthetic feedback.
A content analysis of e-mail communication between primary care providers and parents.

Background. E-mail exchange between parents of patients and providers has been cited by the Institute of Medicine as an important aspect of contemporary medicine; however, we are unaware of any data describing actual exchanges. Objective. The purpose of this study was to evaluate the content of e-mails between providers and parents of patients in pediatric primary care, as well as parent attitudes about e-mail. Design/Methods. Over a 6-week period, all e-mail exchanges between 2 primary care pediatricians and their patients’ parents were evaluated and coded. An exchange was defined as the e-mails between parent and primary care provider about a single inquiry. Parents also completed a questionnaire regarding this service. Results. Of 55 parents, 54 (98%) agreed to have their e-mails with their pediatrician reviewed. The 54 parents generated 81 e-mail exchanges; 86% required only 1 e-mail response from the pediatrician, and the other 14% required an average of 1.9 responses. E-mail inquiries were all for nonacute issues (as judged by S.G.A.) and included inquiries about a medical question (n = 43), medical update (n = 20), subspecialty evaluation (n = 9), and administrative issue (n = 9). The 81 exchanges resulted in 9 appointments, 21 phone calls, 4 subspecialty referrals, 34 prescriptions or recommendations for over-the-counter medications, 11 administrative tasks, and 1 radiograph. Of 91 pediatrician-generated e-mails, 39% were sent during the workday (9 am to 5 pm, Monday to Friday), 44% were sent on weeknights, and 17% were sent on weekends. During the study period, the 2 physicians estimated an average of 30 minutes/day spent responding to e-mail. Of the 54 parents, 45 (83%) returned the survey; 93% were mothers and 86% had completed college. Ninety-eight percent were very satisfied with their e-mail experience with their pediatrician. Although 80% felt that all pediatricians should use e-mail to communicate with parents and 65% stated they would be more likely to choose a pediatrician based on access by e-mail, 63% were unwilling to pay for access. Conclusions. This is the first study to describe actual e-mail exchange between parents and their providers. Exchanges seem to be different from those generated by the telephone, with more e-mails related to medical versus administrative issues and more resulting in office visits. Approximately 1 in 4 exchanges result in multiple e-mails back and forth between parent and provider. Parents who have actually exchanged e-mails with their providers overwhelmingly endorse it, although they are reluctant to pay for it.
Thermodynamic Stability of High-K Dielectric Metal Oxides ZrO 2 and HfO 2 in Contact with Si and SiO2

We present experimental results regarding the thermodynamic stability of the high-k dielectrics ZrO2 and HfO2 in contact with Si and SiO2. The HfO2/Si interface is found to be stable with respect to formation of silicides whereas the ZrO2/Si interface is not. The metal oxide/SiO2 interface is marginally unstable with respect to formation of silicates. Cross-sectional transmission electron micrographs expose formation of nodules, identified as silicides, across the polysilicon/ZrO2/Si interfaces but not for the interfaces with HfO2. For both ZrO2 and HfO2, the X-ray photoemission spectra illustrate formation of silicate-like compounds in the MO2/SiO2 interface.
Prominent microscopic effects in microfabricated fluidic analysis systems

Microfabricated fluidic systems allow complex chemical analyses to be performed on sub-nanoliter volumes of sample. Compared to macroscopic systems, these devices offer many advantages, including the promise of performing some analytical functions more rapidly and on smaller samples. However, miniaturization of analytic instruments is not simply a matter of reducing their size. At small scales, different effects become more prominent, rendering some processes inefficient and others useless. The small scales also permit the creation of novel devices, such as the H- filter, which we are using to extract analytes from whole blood. Fluid flow in microfluidic systems is entirely dominated by viscous forces, making diffusion the sole mechanism of mixing. In addition, a larger fraction of molecules are lost to surface adsorption as devices shrink. This paper examines some of the issues involved in device miniaturization, specifically those phenomena that become increasingly dominant.
Neural Responses to Partner Rejection Cues

Little is known about neural responses in the early automatic-stage processing of rejection cues from a partner. Event-related potentials (ERPs) offer a window to study processes that may be difficult to detect via behavioral methods. We focused on the N400 ERP component, which reflects the amount of semantic processing prompted by a target. When participants were primed by attachment-related contexts ("If I need help from my partner, my partner will be ..."), rejection-related words (e.g., dismissing) elicited greater N400 amplitudes than acceptance-related words (e.g., supporting). Analyses of results for nonattachment primes suggest that these findings were not simply caused by target valence; the brain responds differentially to cues of partner rejection (vs. acceptance) in under 300 ms. Moreover, these early-stage neurophysiological responses were heightened or dampened as a function of individuals' adult attachment; women characterized by high anxiety and low avoidance showed the greatest N400 responses to cues of partner rejection (vs. acceptance).
Congenital transposition of the great arterial trunks

Abstract In this study, five cases of transposition of the arterial trunks are presented (Table I). There are four cases of complete transposition according to the older classification of Rokitansky, and one case of partial transposition of the arterial trunks. Thus, according to Spitzer's more recent classification there are four cases of group III, representing a lack of torsion of the arterial trunks, and one case of group II, representing partial torsion. The youngest patient was eighteen days of age and the oldest lived for seven months. In four of the five cases, the ductus arteriosus was patent but in one case it was represented by a mere fibrous cord and there was dimpling of the intimal surface of the pulmonary artery and aorta over the respective points of junction with the ductus arteriosus. In one case the foramen ovale was closed by a thin membrane, and it was but a slitlike opening in another case. The interventricular septum was intact in three of the five cases and patent in two of them. The patency was attributable to an absence of the membranous portion of the septum. Systolic murmurs were audible in four of the five cases, but the patency of the fetal passages might well account for these murmurs. In two cases there was associated situs inversus. In four of the five cases the diagnosis of congenital heart disease was made without qualification before the patient died. The electrocardiogram indicated the presence of auriculoventricular dissociation in one case in which an interventricular septal defect existed.
Comparison of Models for Mixture Transport Properties for Numerical Simulations of Ablative Heat-Shields

rst part of the study, the results predicted using Wilke’s mixing rule with species viscosities calculated using Blottner’s curve ts and species thermal conductivities determined using Eucken’s relation are compared to the results obtained using Gupta’s mixing rule with collision cross-section (CCS) data. The Wilke/Blottner/Eucken model overpredicts the heat transfer to the surface relative to the Gupta/CCS model by as much as 60%. The Wilke/Blottner/Eucken model also overpredicts the mass blowing rate due to the removal of bulk carbon by as much as 25% compared to the Gupta/CCS model. In the second part of the study, the eects of the mass diusion model are assessed using Fick’s, modied Fick’s, self-consistent eective binary diusion (SCEBD), and Stefan-Maxwell models. The results show that the oweld properties calculated using modied Fick’s, SCEBD, and Stefan-Maxwell models are in good agreement. Fick’s model overpredicts the heat transfer and mass blowing rate by as much as 20% relative to the Stefan-Maxwell model.
Exceptional Convergent Evolution in a Virus

Replicate lineages of the bacteriophage C#JX 174 adapted to growth at high temperature on either of two hosts exhibited high rates of identical, independent substitutions. Typically, a dozen or more substitutions accumulated in the 5.4kilobase genome during propagation. Across the entire data set of nine lineages, 119 independent substitutions occurred at 68 nucleotide sites. Over half of these substitutions, accounting for one third of the sites, were identical with substitutions in other lineages. Some convergent substitutions were specific to the host used for phage propagation, but others occurred across both hosts. Continued adaptation of an evolved phage at high temperature, but on the other host, led to additional changes that included reversions of previous substitutions. Phylogenetic reconstruction using the complete genome sequence not only failed to recover the correct evolutionary history because of these convergent changes, but the true history was rejected as being a significantly inferior fit to the data. Replicate lineages subjected to similar environmental challenges showed similar rates of substitution and similar rates of fitness improvement across corresponding times of adaptation. Substitution rates and fitness improvements were higher during the initial period of adaptation than during a later period, except when the host was changed.
Confounding of Indirect Effects in the “Real World”: Exploring the Range of Bias due to a Common Cause of the Mediator and Outcome

Several investigators have demonstrated that assessment of indirect effects is biased in the presence of a common cause of the intermediate variable and the outcome. However, little work has been done to determine the degree of bias that will be caused by this type of confounding, and whether this bias will materially affect the identification of indirect effects. To address this crucial question, we have developed simulations based on a sufficient-component cause model for mediation. Confounding of the mediator can be introduced into such a model by specifying a common component cause of the intermediate variable and the outcome. By testing a range of prevalence proportions for each independent component cause, we vary both mediational effects and the strength of confounding. These simulations are designed to yield both (1) the true indirect effect of interest (pure and/or total indirect effect) and (2) the observed indirect effect. A comparison of these values indicates the range of bias due to uncontrolled confounding of the intermediate variable. Simulation techniques will be applied to a motivating example from the Health Effects of Arsenic Longitudinal Study. In this example, arsenic exposure is associated with mortality, and the investigators hypothesize that this association is at least partially mediated through skin lesions. Based on known prevalences and strengths of association, simulations will be developed to assess the degree to which inference regarding this hypothesis might be biased.
Hsp27 anti-sense oligonucleotides sensitize the microtubular cytoskeleton of Chinese hamster ovary cells grown at low pH to 42 degrees C-induced reorganization.

Chinese hamster ovary (CHO) cells maintained in vitro at pH 6.7 were used to model cells in the acidic environment of tumours. CHO cells grown at pH 6.7 develop thermotolerance during 42°C heating at pH 6.7 and their cytoskeletal systems are resistant to 42°C-induced perinuclear collapse. Hsp27 levels are elevated in cells grown at pH 6.7 and are further induced during 42°C heating, while Hsp70 levels remain low or undetectable, suggesting that Hsp27 is responsible for some of the novel characteristics of these cells. An anti-sense oligonucleotide strategy was used to test the importance of Hsp27 by lowering heat-induced levels of the protein. The response of the microtubular cytoskeleton to heat was used as an endpoint to assess the effectiveness of the anti-sense strategy. Treatment with anti-sense oligonucleotides prevented the heat-induced increase of Hsp27 levels measured immediately following heat. Treatment with anti-sense oligonucleotides also sensitized the cytoskeleton of cells grown at low pH t...
Linear multichannel blind equalizers of nonlinear FIR Volterra channels

Truncated Volterra expansions model nonlinear systems encountered with satellite communications, magnetic recording channels, and physiological processes. A general approach for blind deconvolution of single-input multiple-output Volterra finite impulse response (FIR) systems is presented. It is shown that such nonlinear systems can be blindly equalized using only linear FIR filters. The approach requires that the Volterra kernels satisfy a certain coprimeness condition and that the input possesses a minimal persistence-of-excitation order. No other special conditions are imposed on the kernel transfer functions or on the input signal, which may be deterministic or random with unknown statistics. The proposed algorithms are corroborated with simulation examples.
Enhancement of breakdown voltage using floating metal field plates

Avalanche, multiplication factors are calculated for reverse biased p–n junctions with two different junction terminations. One of these is the negative bevel for which it is shown that, by properly locating a metal field plate of the appropriate size on this bevel, it is possible to increase the breakdown voltage of the junction. The field plate is isolated from the semiconductor by a thin dielectric. Since negative bevelled p-n junctions break down in the bulk, the location and size of the field plate must be such that the peak hulk electric field is spread out and reduced. On the other hand, the field plate must be small enough and/or the isolating dielectric thick enough to keep the surface electric fields induced at the field plate edges below the critical value for surface avalanche breakdown. Application in high voltage diodes, power transistors, or thyristors is possible with the floating meta field plate being used to simply increase breakdown voltage or to increase current carrying area (with no...
Conversational implicatures via general pragmatic pressures

This paper aims to show how general pragmatic pressures, interacting with the context of utterance, can produce specific conversational implicatures -- as well as the lack thereof in nonsupporting environments. Inspired by the work of Merin (1997), Blutner (1998), van Rooy (2003a), Benz et al. (2005), and others, I use probabilities to represent speakers' belief states and the content of their utterances. These values determine an utterance's quality rating and quantity rating. I adapt Roberts' (1996) view of the question under discussion to define a relevance ranking of utterances. These values come together in a definition of felicitous utterance. This definition licenses certain inferences -- relevance implicatures relating to the question under discussion (section 4.1) and a variety of quantity implicatures (sections 4.2-4.3).
Relationship between mutagenesis and carcinogenesis.

Abstract— Since the neoplastic condition is a phenotypic expression of the genome of the tumor cells, it is reasonable to assume that the neoplastic state can be the result of the alteration of gene activity by either mutagenesis or gene modulation. The review of the literature seems to support the hypothesis that both mutations and epigenetic processes are components to carcinogenesis. Consistent with the mutation theory of cancer are: (1) the clonal nature of tumors; (2) the mutagenicity of most (but not all) carcinogens; (3) correlation of high mutation frequencies in cells of cancer-prone human fibro- blasts lacking DNA repair enzymes; (4) correlation of in vitro DNA damage, in vitro mutation and transformation frequencies with in vivo tumorigenesis; (5) age-related incidences of various hereditary tumors; and (6) the correlation between photoreactivation of DNA damage and the biological amelioration of UV-induced neoplasms. Supporting the epigenetic theory of carcinogenesis is the reversion of certain types of neoplastic cells to a state allowing normal development. These latter studies demonstrate the totipotency of the genes in some types of malignant cells. An integrative theory of carcinogenesis is presented that synthesizes the mutation and epigenetic theories with Comings' general theory of carcinogenesis and the 2-stage theory of carcinogenesis. Data are presented that test the predictions of the 2-stage theory of carcinogenesis, and that support the hypothesis that mutagenesis plays a major role in carcinogenesis (initiation phase) and that gene modulation of repressed mutations is responsible for tumor promotion.
Addiction research in a simple animal model: the nematode Caenorhabditis elegans

Genetic analysis in the nematode C. elegans has provided important insights into many aspects of neuronal cell biology, including functions related to addiction. Specifically, genetic and molecular screens to have been used to identify molecules involved in long-term responses to drugs of abuse and to analyze the mechanisms underlying their effects on nervous system development, plasticity, and behavior. This review presents a personal view of addiction-related research in C. elegans, and includes a discussion of technical innovations that have facilitated neurobiological analyses in C. elegans and a look at future prospects drug addiction research in simple animal models.
DDE MODEL OF GENE EXPRESSION: A CONTINUUM APPROACH

This paper presents an analytical study of the stability of the steady state solutions of a gene regulatory network with time delay. The system is modeled as a continuous network and takes the form of a nonlinear delay differential-integral equation coupled to an ordinary differential equation. Two examples are given in which the critical delay causing instability is computed.Copyright © 2008 by ASME
Sawadaea tulasnei Powdery Mildew of Norway Maple (Acer platanoides) in North America

Norway maple leaves bearing powdery mildew were collected from one location in the fall of 2003 and four locations (as much as 1.5 km apart) in the fall of 2005 in Buffalo, NY. No powdery mildew was observed on leaves collected from sugar maples (Acer saccharum) that were present in the vicinity of affected Norway maples at two locations. Trees were located along streets and in yards. Diseased leaves were present throughout tree crowns but lower leaves were more commonly affected. White mycelium was present in irregular, discrete, scattered spots only on the upper surface of leaves and on both sides of wings of samaras. Typically, <10% of the upper leaf area bore visible mycelium. Cleistothecia were present singly or in groups on the mycelium. Morphology of cleistothecia on leaves collected each year, including simple and bifid appendages with uncinate to circinate apices, was sufficient to identify the pathogen to the genus Sawadaea (1). Other characteristics were not sufficiently distinct to make an ide...
When system boundaries dissolve: research opportunities in software architectures for ubiquitous computing and communication

Modern computing technology is creating a growing infrastructure for high performance, nearly ubiquitous computing and communication. This infrastructure extends the reach of computation and information beyond the traditional framework of a computer application running on a fixed set of machines. The architectures that suffice for such traditional software systems that depend on resources controlled by someone other than the developer. I will discuss the architectural challenges of this new setting, describe some promising approaches to handling those challenges, and suggest some research strategies for exploring and developing solutions.
Woody Plant Encroachment and Removal in Mesic Grassland: Production and Composition Responses of Herbaceous Vegetation

The clonal shrub Cornus drummondii is rapidly displacing mesic grassland in the central U.S. due to fire suppression and changes in land use. Once established, this shrub is not readily eliminated by the return of frequent fire, leading to significant and perhaps irreversible shifts in tallgrass prairie structure and function. We assessed the impacts of C. drummondii encroachment on herbaceous aboveground net primary production (ANPP) and plant community structure in tallgrass prairie and the role this species plays in the conversion of grassland ecosystems to shrub/woodlands. We also removed established C. drummondii clones to assess the potential of the grassland ecosystem to recover after shrub dominance. Aboveground net primary production, vegetative cover and species richness and diversity (exclusive of C. drummondii) were significantly reduced beneath shrub islands relative to open grassland, with reductions in ANPP and richness of up to 94 and 45%, respectively. Forbs were the dominant growth form in the C. drummondii understory, and 10 species primarily associated with woodland habitats occurred only within shrub islands. Upon removal of C. drummondii, ANPP, richness and diversity recovered to grassland values within 2 y; however, forbs remained the dominant growth form, comprising 73% of total cover. These results indicate that C. drummondii exerts strong control over the structure and function of unburned mesic grassland ecosystems and that this shrub may be key in the conversion of grasslands to woodlands. Removal of C. drummondii resulted in some aspects of recovery, but the return of graminoid dominance was not attained after 2 y. This represents a legacy effect of C. drummondii of unknown duration. Prevention of woody species encroachment through frequent burning is a preferred management option for this ecosystem.
Single-Molecule Approaches Embrace Molecular Cohorts

Enormous mechanistic insight has been gained by studying the behavior of single molecules. The same approaches used to study proteins in isolation are now being leveraged to examine the changes in functional behavior that emerge when single molecules have company.
Phase-coherent Spectrum from Ultrabroadband Ti:sapphire and Cr:forsterite Lasers Covering the Visible to the Infrared

Few-cycle optical pulses open up new possibilities to investigate various extreme light-matter interactions, which depend on the light electric-field oscillation itself, for example, high-harmonic generation (HHG) for extreme ultraviolet and soft X-ray pulse generation [1]. For further investigations and applications of such phase-sensitive phenomena, single-cycle optical pulse, comprised of only one cycle of the light oscillation, is currently pursued in many laboratories.