cssi/SciSciGPT-SciSciNet huggingface dataset:
Role of Accurate Mass Measurement (±10 ppm) in Protein Identification Strategies Employing MS or MS/MS and Database Searching

We describe the impact of advances in mass measurement accuracy, ±10 ppm (internally calibrated), on protein identification experiments. This capability was brought about by delayed extraction techniques used in conjunction with matrix-assisted laser desorption ionization (MALDI) on a reflectron time-of-flight (TOF) mass spectrometer. This work explores the advantage of using accurate mass measurement (and thus constraint on the possible elemental composition of components in a protein digest) in strategies for searching protein, gene, and EST databases that employ (a) mass values alone, (b) fragment-ion tagging derived from MS/MS spectra, and (c) de novo interpretation of MS/MS spectra. Significant improvement in the discriminating power of database searches has been found using only molecular weight values (i.e., measured mass) of >10 peptide masses. When MALDI-TOF instruments are able to achieve the ±0.5−5 ppm mass accuracy necessary to distinguish peptide elemental compositions, it is possible to matc...
Light-mediated activation reveals a key role for Rac in collective guidance of cell movement in vivo

The small GTPase Rac induces actin polymerization, membrane ruffling and focal contact formation in cultured single cells but can either repress or stimulate motility in epithelial cells depending on the conditions. The role of Rac in collective epithelial cell movements in vivo, which are important for both morphogenesis and metastasis, is therefore difficult to predict. Recently, photoactivatable analogues of Rac (PA-Rac) have been developed, allowing rapid and reversible activation or inactivation of Rac using light. In cultured single cells, light-activated Rac leads to focal membrane ruffling, protrusion and migration. Here we show that focal activation of Rac is also sufficient to polarize an entire group of cells in vivo, specifically the border cells of the Drosophila ovary. Moreover, activation or inactivation of Rac in one cell of the cluster caused a dramatic response in the other cells, suggesting that the cells sense direction as a group according to relative levels of Rac activity. Communication between cells of the cluster required Jun amino-terminal kinase (JNK) but not guidance receptor signalling. These studies further show that photoactivatable proteins are effective tools in vivo.
Industry Information Transfers: The Effect of Information Environment

This study extends the information environment theory of Atiase (1985) that suggests an inverse relation between the information available about a firm and the security price reaction to its release of earnings. Non-announcing firms' security price responses are found to be inversely related to their market value but directly related to the number of peer firm articles appearing in the Wall Street Journal and the historical earnings correlations within their industry. The results suggest that information environment affects the security price relevance of a firm's own and its peer firms' earnings.
Carbon: analysis of spherules and splats formed from the liquid state and of the forms produced by quenching gas and solid

Abstract Spherules, splats, and quenched samples of carbon were analyzed and found to consist largely of carbyne forms of carbon. In addition, some information was obtained on the structure of the spherules and quenched carbon samples.
Rough Contacts Modeled by Nonlinear Coatings

A number of experimental studies [1–3] revealed that the normal displacement in a contact of rough surfaces due to asperities presence is a nonlinear function of local pressure and it can be approximated by a power function of pressure. Originally, a linear mathematical model accounting for surface roughness of elastic solids in contact was introduced by I. Shtaerman [4]. He assumed that the effect of asperities present in a contact of elastic solids can be essentially replaced by the presence of a thin coating simulated by an additional normal displacement of solids’ surfaces proportional to a local pressure. Later, a similar but nonlinear problem formulation that accounted for the above mentioned experimental fact was proposed by L. Galin. In a series of papers this problem was studied by numerical and asymptotic methods [5–9]. The present paper has a dual purpose: to analyze the problem analytically and to provide some asymptotic and numerical solutions. The results presented below provide an overview of the results obtained on the topic and published by the author earlier in the journals hardly accessible to the international tribological community (such as Russian and mathematical journals) and, therefore, mostly unknown by tribologists. A number of recent publications on contacts of rough elastic solids supports the view that these results are still of value to the specialists involved in nanotribology. The existence and uniqueness of a solution of a contact problem for elastic bodies with rough (coated) surfaces is established based on the variational inequalities approach. Four different equivalent formulations of the problem including three variational ones were considered. A comparative analysis of solutions of the contact problem for different values of initial parameters (such as the indenter shape, parameters characterizing roughness, elastic parameters of the substrate material) is done with the help of calculus of variations and the Zaremba-Giraud principle of maximum for harmonic functions [10,11]. The results include the relations between the pressure and displacement distributions for rough and smooth solids as well as the relationships for solutions of the problems for rough solids with fixed and free contact boundaries. For plane and axially symmetric cases some asymptotic and numerical solutions are presented.Copyright © 2007 by ASME
Quantitative Assessment of Changes in Intrinsic Molecular Motion using Support Vector Machines

The ensemble of 3-d configurations exhibited by a biomolecule, that is, its intrinsic motion, can be altered by several environmental factors, and also by the binding of other molecules. Quantification of such induced changes in intrinsic motion is important because it provides a basis for relating thermodynamic changes to changes in molecular motion. This task is, however, challenging because it requires comparing two high-dimensional datasets. Traditionally, when analyzing molecular simulations, this problem is circumvented by first reducing the dimensions of the two ensembles separately, and then comparing summary statistics from the two ensembles against each other. However, since dimensionality reduction is carried out prior to ensemble comparison, such strategies are susceptible to artifactual biases from information loss. Here we introduce a method based on support vector machines that yields a normalized quantitative estimate for the difference between two ensembles after comparing them directly against one another. While this method can be applied to any molecular system, including non-biological molecules and crystals, here we show how it can be applied to identify the specific regions of a paramyxovirus G-protein that are affected by the binding of its preferred human receptor, Ephrin-B2. This protein-protein interaction essentially regulates viral fusion. Specifically, for every residue in the G-protein, we obtain separately a quantitative difference between the ensemble of configurations they sample in the presence and in the absence of Ephrin-B2. These ensembles were generated using molecular dynamics simulations. Rank-ordering and then mapping the residues that undergo the greatest change in motion on to the 3-d structure of the G-protein reveals that they are clustered primarily on a single contiguous facet of the protein, and include the set that is known experimentally to play a vital role in regulating viral fusion.
Anorectal Anatomy and Physiology

The rectum and anal canal form the last portion of the gastrointestinal tract. The rectum serves as a reservoir for fecal contents, and the anal canal regulates continence and defecation via synchronization of events regulated by complex interactions between sympathetic and parasympathetic nerves, striated and smooth muscle, and environmental factors. Normal function can be compromised by various pathologies. Investigation into these pathologies includes a detailed history and thorough physical exam and can be augmented by a number of different studies, including manometry, electromyelography, defecography, nerve stimulation, and compliance. Some of these techniques have incorporated the use of ultrasound and magnetic resonance imaging.
Distribution of Late Cretaceous and Early Tertiary Non-Marine Strata in West-Central Alberta: ABSTRACT

Investigation of Late Cretaceous and Tertiary non-marine strata of west-central Alberta has been undertaken for the Research Council of Alberta to solve problems of origin, correlation and age, structure, and nomenclature. Sediments are exposed in or underlie a belt extending from the Foothills northeast to the line Drumheller-Edmonton-Whitecourt and from Calgary-Drumheller northwest to the Athabasca River. Units of immediate concern include Edmonton, Brazeau, Paskapoo, and Saunders. Abundant well records afford an opportunity for correlation between northeastern and southwestern outcrop belts, as well as to study regional and local sedimentary patterns. Purpose of this paper is to present the results of preliminary subsurface studies of regional relationships among the non-marine strata that are exposed in various areas. On the northeast, formations include the Belly River, Bearpaw (marine), Edmonton (all Cretaceous) and lower Paskapoo (Tertiary). The part of the section commonly recognized as Cretaceous is approximately 2,600 feet thick. Except for the marine Bearpaw, the units are almost entirely non-marine, composed of lenticular shales, siltstones, sandstones, and coal beds. Similar rocks, assigned to the Paskapoo, overlie the Edmonton. In the subsurface, near Lacombe and not far west of Edmonton, the Bearpaw passes into terrestrial beds, so that non-marine units are not so easily separated. Southwestward, the entire sequence becomes coarser (sandstones more abundant, and coarser-grained), and thickens markedly on the order of 20 feet per mile, across the strike and toward the Foothills. Equivalent units in and near the Foothills include those called the Brazeau, Saunders, and Paskapoo, but published correlations are open to question. End_of_Article - Last_Page 272------------
Neural network for restoration of signals blurred by a random, shift-variant impulse response function.

A novel regularization technique is proposed for the restoration of signals distorted by a stochastic, shift-variant impulse response (blur) function and additive noise. The generic ill-posed inverse problem is formulated as a constrained optimization problem wherein a new cost function, termed stochastic constrained restoration error energy , is minimized. For signals that are quantized in amplitude and sampled in time or space, an artificial neural network is developed and implemented for computational efficiency. By matching the cost function with the energy function of the neural network, the interconnection strengths and bias inputs of the neural network are related to the degraded signal, blur statistics, and constraint parameters. The solution that minimizes the energy function of the neural network is then obtained by the simulated annealing algorithm. Simulation results are also provided to demonstrate the effectiveness of the proposed approach.
Color confinement and the quantum-chromodynamic vacuum. II. Gluon propagation and the Coulomb interaction

In an earlier paper the color-confining interaction was identified as the vacuum expectation value of the modified Coulomb operator. This vacuum expectation value is related first to the QCD running coupling constant and then to the gluon propagator in the physical vacuum. If the propagator is less singular at p=0 than predicted from perturbation theory, the required infrared singularity in the interaction arises naturally. Nonperturbative solutions for both the running coupling constant and the modified Coulomb interaction are presented.
Effect of Combining Imidacloprid and Diatomaceous Earth with Beauveria bassiana on Mole Cricket (Orthoptera: Gryllotalpidae) Mortality

Sublethal doses of three orthopteran-derived strains of Beauveria bassiana (Balsamo) Vuillemin were topically applied to adult southern mole crickets, Scapteriscus borellii Giglio-Tos (Orthoptera: Gryllotalpidae), and tested in combination with substrate treatments of diatomaceous earth (DE) and imidacloprid. Crickets treated only with the high doses (10(8) conidia per cricket) of each of the three B. bassiana strains exhibited the shortest survival times as well as the highest percentage mortality at 28 d after treatment. However, these treatments did.not differ significantly from any of the diatomaceous earth combination treatments. Two of the strains tested, 5977 and 3622, exhibited synergistic interactions with DE, whereas the third strain, GHA, was not significant for synergy. Mortality caused by the combination treatment was still greater than the expected additive effect. DE abrades the insect cuticle and absorbs cuticular lipids, aiding the entry of germinating conidia into the mole cricket hemocoel. None of the three strains exhibited synergy when combined with imidacloprid, and mortality of all combination treatments was less than additive. For strain 5977, there was an antagonistic interaction with imidacloprid. It was difficult to obtain <30% mortality for imidacloprid only treatments, which was considered the upper limit for sublethal doses. The mean percentage mortality caused by imidacloprid was 37.5%, and this high percentage made it difficult for any combination treatment to cause significantly more mortality than the expected additive effect. These results clarify the interactions of other control products with B. bassiana and provide a basis for a reduced pesticide approach to mole cricket control.
1H magnetic resonance spectroscopy in dementia

Neuroimaging biomarkers are increasingly being used in clinical practice for early diagnosis and differential diagnosis of dementia and in clinical trials as an outcome measure. Proton magnetic resonance spectroscopy has shown promise in dementia as a diagnostic biomarker with the ability to detect preclinical disease and amnestic mild cognitive impairment and provide ancillary information to distinguish among dementia subtypes. Alzheimer’s disease is characterized by decreased N-acetylaspartate-to-creatine (NAA/Cr) and elevated myo-inositol-to-creatine (mI/Cr) levels. Dementia with Lewy bodies is characterized by normal NAA/Cr levels in the posterior cingulate and elevated choline-to-creatine (Cho/Cr). Vascular dementia demonstrates decreased NAA/Cr but preserved Cho/Cr and mI/Cr in the posterior cingulate. Despite promising studies, MRS is not routinely used in the evaluation for dementia in clinical practice. Improving knowledge of the pathological basis of the metabolite ratio abnormalities, longitudinal studies, and better standardization of the MRS technique may improve the application in dementia.
Deformation, yielding, fracture and fatigue behavior of conventional and highly cross-linked ultra high molecular weight polyethylene

Medical grade ultra high molecular weight polyethylene (UHMWPE) has been used as the bearing surface of total joint replacements for over four decades. These polymeric devices are susceptible to accumulated cyclic damage in vivo. Wear debris formation that ultimately leads to a need for revision surgery is linked to the plasticity, fatigue and fracture mechanisms of UHMWPE. This paper examines the deformation, yielding, fracture and fatigue behavior of conventional and highly cross-linked medical grade UHMWPE. Such properties play an important role in determining the long-term success of orthopedic devices. The mechanical properties discussed include the deformation behavior of UHMWPE, the yielding associated with quasi-static tension and compression, fracture toughness, cyclic loading, and fatigue resistance.
An antenna for limited scan in one plane: Design criteria and numerical simulation

An analytical and numerical study has been performed on a novel design scheme for an antenna system for limited one-dimensional scan. The system has a number of control elements approximately equal to the minimum theoretically compatible with the aperture size and field of view (FOV). The radiating structure consists of a "bootlace" lens with linear outer and circular inner profiles. This geometry plays a basic role in determining excellent scan performance over a moderate frequency band. A linear array whose size depends critically upon the scan requirements and the lens focal length is located on the focal plane and is focussed onto the inner lens profile. The array is fed by a hybrid network (HN) performing a spatial Fourier transformation. The input ports of the HN are fed by the output ports of a beam forming network (BFN) through a set of variable phase shifters. The BFN has separate input ports for the sum and difference patterns, controlled independently, The system works as follows. The antenna illumination is synthesized as the weighted superposition of components illuminations or "overlapping subarrays" each of which is due to the excitation of one of the ports of the HN. The amplitudes of the subarray excitations are fixed and determined by the power divisions provided by the BFN. Their phases are controlled by the set of variable phase shifters. A desirable feature of the scheme is that for a fixed phase shifter setting neither the beam scan nor its width changes for a moderate frequency variation. Through a suitable design of the BFN, ultralow sidelobes outside the FOV can be achieved at the expense of a slight reduction of the illumination efficiency, which is, however, always high, since the aperture is fully used. Extensive numerical computations for an antenna having a half-power beamwidth of 1.2\deg show that the sum beam can be scanned in a sector greater than \pm3 beams, on a band of 20 percent with excellent performance form the viewpoint of gain and sidelobes-the scan sector being slightly less for the difference beam.
Accounting, New Public Management and American Politics: Theoretical Insights into the National Performance Review

Abstract Borrowing from the work of political theorists Sheldon Wolin and William Connolly, this essay seeks to provide additional rationalization for the expansion of accounting within domains like the public sector. We suggest that such an expansion is intimately linked to social and cultural transitions which have led political theorists to not only question modern political theory but to also recognize the political significance of practices like accounting to political theory. We contend that these same transitions also make possible expansions of accounting through New Public Management (NPM) initiatives like the U.S.'s National Performance Review (NPR). Seen in this way, accounting theory begins to move away from its traditional status as, in Foucault's (1995) terms, a “subjugated” knowledge and to take on a serious intellectual priority within political theory. A primary objective is to provide at least a partial rational-analytic typos useful in understanding the codetermined relationship between accounting and politics.
Michigan's Experiences with the Federal Education Block Grant.

Abstract The results of a detailed study undertaken in Michigan to ditermine the impact of the Chapter 2 block grant in its first two years of implemention 1982–1983 and 1983–1984 are summarized in this article Following a discussion of changes in intergovernmental relationships that resulted from Chapter 2 major state decisions snd actions that centered on the block grant program are described General and specific impressions of the impact of Chapter 2 based on an in depth study of nine public school districts and four non-public schools comprise the major portion of the article.
Anisotropy of the enhanced electron mass in indium

Abstract We have calculated the mass enhancement λ k due to phonons as a function of position along the central [110] cyclotron orbits on the second and third zone Fermi surfaces in indium. The third zone λ k are about 50% larger than those on the second zone in good agreement with cyclotron mass measurements.
Development of weekly high-dose calcitriol based therapy for prostate cancer ☆

Calcitriol, the principal biologically active ligand of the Vitamin D receptor (VDR), has been shown to inhibit cancer cell proliferation in in vitro and in vivo models of prostate cancer and a wide range of other neoplasms. In addition, calcitriol's activity appears to be additive, and in some experimental systems, synergistic with dexamethasone and several cytotoxic chemotherapy agents. While effects on progression through the cell cycle, induction of apoptosis, inhibition of angiogenesis, and reduction in tumor invasiveness have been demonstrated, the exact mechanisms of VDR-mediated antineoplastic activity remain incompletely understood. Antineoplastic activity of calcitriol requires substantially supraphysiologic concentrations of this compound. Dose escalation of calcitriol administered daily was severely limited by predictable hypercalcemia and/or hypercalcuria. This limitation has been overcome with intermittent dosing of calcitriol. At Oregon Health & Science University, weekly oral administration of calcitriol allowed the attainment of peak serum calcitriol concentrations well above 1 nM, a concentration that inhibits prostate cancer proliferation by more than 50% in vitro. Weekly high-dose calcitriol was then combined with weekly docetaxel in a Phase II clinical trial carried out in men with metastatic androgen-independent prostate cancer. Treatment resulted in PSA response (defined as a confirmed 50% reduction) in 81% of patients. This level of activity, as well as the median time to progression of 11.4 months and median survival of 19.5 months, compared favorably to results with docetaxel alone and led to the development of a recently initiated randomized trial of docetaxel with calcitriol or placebo in the same patient population.
Myo-inositol binding site of concanavalin A.

CONCANAVALIN a agglutinates erythrocytes from various animal species, yeast cells, starch granules and some bacteria1 and it complexes with many other substances which contain specific saccharides2–5. When bound to saccharides of cell surfaces, concanavalin A will return tissue cultures of transformed fibroblasts to normal growth rates6 and inhibit growth of various tumours in vivo.7,8 The protein equivalent weight per saccharide, transition metal ion and Ca2+ ion binding sites has been shown by equilibrium dialysis to be about 30.0003,9. Transition metal and Ca2+ ions are both required for the saccharide binding9. The crystallographic asymmetric unit contains a subunit of 27,000 daltons10–12. Four subunits, which are identical, interact through a point of 222 symmetry to form a “pseudotetrahedral” molecule of about 108,000 daltons10. Moreover, the pair of subunits related around the x-axis are more firmly associated than the other two pairs10.
Dynamics of kinematic chains

In this article we derive the equations of motion of a kinematic chain using concepts naturally associated with the special euclidean group. A simple and coordinate-free formula for the kinetic energy of a rigid body is used to express the kinetic energy of an open chain. From this, the dynamical equations in the Lagrangian form follow easily. The structure of the equations of motion is sufficiently transparent so that one may gain insight into nontrivial problems involving analysis and design. We illustrate the applicability of this formalism by investigating the design of manipulators with configuration- independent and separable kinetic energy.
Intermolecular Enolate Heterocoupling: Scope, Mechanism, and Application

This full account presents the background on, discovery of, and extensive insight that has been gained into the oxidative intermolecular coupling of two different carbonyl species. Optimization of this process has culminated in reliable and scalable protocols for the union of amides, imides, ketones, and oxindoles using soluble copper(II) or iron(III) salts as oxidants. Extensive mechanistic studies point to a metal-chelated single-electron-transfer process in the case of copper(II), while iron(III)-based couplings appear to proceed through a non-templated heterodimerization. This work presents the most in-depth findings on the mechanism of oxidative enolate coupling to date. The scope of oxidative enolate heterocoupling is extensive (40 examples) and has been shown to be efficient even on a large scale (gram-scale or greater). Finally, the method has been applied to the total synthesis of the unsymmetrical lignan lactone (-)-bursehernin and a medicinally important 2,3-disubstituted succinate derivative.
Array seismology advances research into Earth's interior

The densification of regional seismic networks, the proliferation of temporary portable seismometer deployments, and the increasing ease with which traditional seismic array data may be obtained all facilitate a new wave of imaging Earth's interior at the shortest-ever possible scale lengths using array methods. In fact, seismic array techniques are often necessary for retrieval of subtle, yet important, deep Earth seismic structures, particularly those containing fine-scale features. While only a handful of investigations over the past few decades have used traditional seismic array processing for imaging Earth's deep interior, the recent data renaissance in our community enables utilization of methods once predominantly devoted to the near surface for peering deep into the planet, from upper mantle discontinuities to the solid inner core, from the earthquake source to near-surface receiver structure. Thus, it is anticipated that this branch of seismology will become increasingly important in the pursuit of deciphering Earth structure and the earthquake source in unprecedented detail, especially with the emergence of the U.S. National Science Foundation (NSF)-funded USArray of the EarthScope initiative (see http://www.earthscope.org).
Effect of Terbuthylazine-2-hydroxy at Environmental Concentrations on Early Life Stages of Common Carp (Cyprinus carpio L.)

The aim of the study was to investigate effects of the triazine's herbicide terbuthylazine-2-hydroxy on early life stage of common carp (Cyprinus carpio L.) through antioxidant indices, mortality, growth, development, and histopathology. Based on accumulated mortality in the experimental groups, lethal concentrations of terbuthylazine-2-hydroxy were estimated at 35-day LC50 = 10.9 mg/L terbuthylazine-2-hydroxy. By day 15, fish were exposed to 3.5 mg/L and by day 26, fish were exposed to 0.0029 mg/L; real environmental concentration in Czech rivers, 0.07 mg/L, 1.4 mg/L, and 3.5 mg/L terbuthylazine-2-hydroxy, showed significantly lower mass and total length compared with controls. Based on inhibition of growth in the experimental groups, lowest observed effect concentration (LOEC) = 0.002 mg/L terbuthylazine-2-hydroxy and no observed effect concentration (NOEC) = 0.0001 mg/L terbuthylazine-2-hydroxy. No significant negative effects on hatching or embryo viability were demonstrated at the concentrations tested, but significant differences in early ontogeny among groups were noted. Fish from the two highest tested concentrations showed a dose-related delay in development compared with the controls. Total superoxide dismutase (SOD) activity was significant lower in all groups testedly for terbuthylazine-2-hydroxy compared with the control group. At concentrations of 1.4 and 3.5 mg/L damage to caudal kidney tubules when compared to control fish was found.
2 Biopsy diagnosis of systemic vasculitis

A definitive diagnosis of virtually all vasculitides requires histological documentation. Although each major type of systemic vasculitis may have its own unique features, variability and overlaps still exist, and histopathological specificity is rarely an absolute discriminator. The interpretation of biopsies for the diagnosis of vasculitis remains more an art than a science, and it requires full and complete correlation with historical, clinical, laboratory, and angiographic findings.
Cerebral complications of nonaccidental head injury in childhood

Abstract Patterns of cerebral parenchymal injury and their relationship to outcome morbidity are evaluated in this retrospective study of 14 children with confirmed nonaccidental head injury (NAHI). The mean age at time of injury was 12 months 6 days, mean Children’s Coma Score was 5.36, and mean postinjury follow-up was 17 months 12 days. All patients had acute subdural hematoma (interhemispheric or convexity) on initial CT imaging. Two major groups of children were identified from initial CT scans; those with diffuse cerebral hypoattenuation (n = 7) and those with focal cerebral hypoattenuation (n = 7). The two groups differed significantly by age (diffuse group, mean age 5 months 9 days ± 36 days; focal group, mean age 19 months 3 days ± 6 months 9 days; P
Protein-mediated DNA looping in a fluctuating micromechanical environment

ABSTRACT Forces on the order of a hundred femtonewtons can drastically prevent the formation of protein-mediated DNA loops, which are a common regulatory component of cellular function and control. To investigate how such an acutely sensitive mechanism might operate within a noisy environment, as might typically be experienced within a cell, we have studied the response of DNA loop formation under an optically induced, fluctuating, mechanical tension. We show that mechanical noise strongly enhances the rate of loop formation. Moreover, the sensitivity of the loop formation rate to mechanical fluctuations is relatively independent of the baseline tension. This suggests that tension along the DNA molecule could act as a robust means of regulating transcription in a noisy in vivo environment. Keywords: optical tweezers, lac repressor, ge ne regulation, fluctuations, noise 1. INTRODUCTION Cells are both extremely crowded and rich with internal activity. Biomolecules within the cellular interior, such as DNA, are subject to mechanical forces resulting from a variety of processes, from the binding of proteins and enzymes to the packing of chromosomes
Distinct roles of two Mg2+ binding sites in regulation of murine flap endonuclease-1 activities.

Removal of flap DNA intermediates in DNA replication and repair by flap endonuclease-1 (FEN-1) is essential for mammalian genome integrity. Divalent metal ions, Mg2+ or Mn2+, are required for the active center of FEN-1 nucleases. However, it remains unclear as to how Mg2+ stimulates enzymatic activity. In the present study, we systemically characterize the interaction between Mg2+ and murine FEN-1 (mFEN-1). We demonstrate that Mg2+ stimulates mFEN-1 activity at physiological levels but inhibits the activity at concentrations higher than 20 mM. Our data suggest that mFEN-1 exists as a metalloenzyme in physiological conditions and that each enzyme molecule binds two Mg2+ ions. Binding of Mg2+ to the M1 binding site coordinated by the D86 residue cluster enhances mFEN-1's capability of substrate binding, while binding of the metal to the M2 binding site coordinated by the D181 residue cluster induces conformational changes. Both of these steps are needed for catalysis. Weak, nonspecific Mg2+ binding is likel...
The VELscience project: Middle schoolers' engagement in student-directed inquiry within a virtual environment for learning

Schools have long fallen short in helping students to develop the skills necessary to engage in scientific inquiry. Emerging technology-based programs can potentially address this shortfall, but the field lacks clear models of instructional materials capable of doing so. The VELscience project seeks to provide a model for one type of software (virtual environments for learning, or VELs) designed to engage students in student-directed inquiry. In student-directed inquiry, students are given a topic or task, then pose questions, design the investigation, collect and analyze data, draw conclusions and publish their findings. This study examined the effectiveness of this model through observations of middle school students who completed Hurricane Hal, a VEL in which students determine the ecological impact of a natural disaster on a wetlands ecosystem. The results suggest that this program successfully engaged students in student-directed inquiry.
Matchmaking: A New MapReduce Scheduling Technique

MapReduce is a powerful platform for large-scale data processing. To achieve good performance, a MapReduce scheduler must avoid unnecessary data transmission by enhancing the data locality (placing tasks on nodes that contain their input data). This paper develops a new MapReduce scheduling technique to enhance map task's data locality. We have integrated this technique into Hadoop default FIFO scheduler and Hadoop fair scheduler. To evaluate our technique, we compare not only MapReduce scheduling algorithms with and without our technique but also with an existing data locality enhancement technique (i.e., the delay algorithm developed by Face book). Experimental results show that our technique often leads to the highest data locality rate and the lowest response time for map tasks. Furthermore, unlike the delay algorithm, it does not require an intricate parameter tuning process.
LAWYER'S DUTY TO DISCUSS ALTERNATIVE DISPUTE RESOLUTION IN THE BEST INTEREST OF THE CHILDREN

Alternative dispute resolution (ADR) has been championed for its power to devise agreements that meet the parents' and the children's needs and for its ability to encourage parties to work together, eventually leading to stable agreements. The Model Rules of Professional Conduct do not create any ethical duty to advise, suggest, or encourage lawyers to discuss ADR with their domestic relations client. In the medical field, patients are given a choice of treatment under the informed consent doctrine, but there is no analogous doctrine in the legal field. The Model Rules of Professional Conduct should be revised to reflect the best interests of children, as well as client choice. Clients, specifically parents in domestic relation matters, are entitled to know their options, and lawyers should be obligated to provide them with the information that will enable them to make informed decisions–decisions that will benefit their children and ultimately our nation.
Preliminary observations on the association between simple metopic ridging in children without trigonocephaly and the Chiari I malformation.

Historically, there have been no accounts of an association between simple metopic ridging and the Chiari I malformation. We prospectively evaluated 50 children with simple metopic ridges and found that 30% of these patients had a Chiari I malformation. During the period in which this screening for simple metopic ridges was performed, only 9% of the total patient population (324) was diagnosed as having a Chiari I malformation. We hypothesize that small decreases in anterior fossa volume in children with a simple metopic ridge and no other clinical findings of trigonocephaly may increase their chance of having a Chiari I malformation that becomes symptomatic. In addition, simple metopic ridging should perhaps be added to the list of bony anomalies associated with the Chiari I malformation, such as atlantal assimilation and retroverted odontoid processes. Future studies aimed at calculating anterior fossa volumes in children with a Chiari I malformation and imaging all children with simple metopic ridges are now necessary to ascertain if there is an increased risk of these patients becoming symptomatic with a hindbrain hernia or having a hindbrain hernia, respectively.
Emergency Decay Heat Removal in a GEN-IV Gas-Cooled Fast Reactor

A series of transient analyses using the system code RELAP5-3d has been performed to confirm the efficacy of a proposed hybrid active/passive combination approach to the decay heat removal for an advanced 2400 MWt GEN-IV gas-cooled fast reactor. The accident sequence of interest is a station blackout simultaneous with a small break (10 sq.inch/0.645 m{sup 2}) in the reactor vessel. The analyses cover the three phases of decay heat removal in a depressurization accident: (1) forced flow cooling by the power conversion unit (PCU) coast down, (2) active forced flow cooling by a battery powered blower, and (3) passive cooling by natural circulation. The blower is part of an emergency cooling system (ECS) that by design is to sustain passive decay heat removal via natural circulation cooling 24 hours after shutdown. The RELAP5 model includes the helium-cooled reactor, the ECS (primary and secondary side), the PCU with all the rotating machinery (turbine and compressors) and the heat transfer components (recuperator, pre-cooler and inter-cooler), and the guard containment that surrounds the reactor and the PCU. The transient analysis has demonstrated the effectiveness of passive decay heat removal by natural circulation cooling when the guard containment pressure is maintained at or abovemore » 800 kPa. (authors)« less
High-frequency optical Fourier transform analyzer for whole-field specklegram reconstruction

Conventional optical systems used for whole-field specklegram reconstruction are limited by the size of the lenses, the uniformity of the collimated beam, and the off-axis capability. Outside the Fresnel and paraxial regions, the fringe patterns will suffer from various aberrations. The maximum obtainable sensitivity, therefore, is severely restrained. A new optical system and instrument-the high-frequency optical Fourier transform analyzer-specifically designed for whole-field specklegram reconstruction, can extrapolate the spectrum beyond the passband. It can extract information at any point within the hemisphere at which diffraction occurs. It also minimizes aberrations, allowing the sensitivity of speckle metrology to be increased to levels commensurate with those of moire interferometry.
Architecting a family of space tugs based on orbital transfer mission scenarios

The consequences of satellite misplacement or collision with space debris reach far beyond the realm of money. The vast number of people affected by the loss of just one spacecraft indicates the vulnerability of our society to spacecraft failure. Thus, one of the biggest problems that satellite makers face today is the lack of a margin of error of any type. This thesis analyzes the business case for employing a special type of on-orbit servicer referred to as a space tug as an alternative to redundancy and replacement option. The main objective of a space tug is to prevent satellites from prematurely ending their missions. It was found to be more realistic to design a tug (or tugs) that service groups of satellites with similar orbital and physical characteristics, rather than to design a “monster” vehicle expected to traverse the huge distances between LEO and GEO and deal with satellites of all types and sizes. Thus, the approach of this work was based on the exploration of the entire satellite population currently in orbit around Earth and on the identification of potential target groups of satellites, along with mission scenarios for servicing each of these groups. Eight mission scenarios were identified as most necessary. Two of them—GEO communications satellite retirement and satellite rescue—were presented as case studies to illustrate the modeling approach suggested by this thesis. The ultimate objective of the research was to create a family of modular, economically feasible space tugs that used a common platform and shared various components, which would allow to provide relatively inexpensive and responsive ondemand tugging services. It was found that the optimal space tug for GEO retirement missions should be initially parked in the GEO belt and be controlled via supervision. This space tug should have a 300-kg low capability grappling mechanism and utilize storable bipropellant (Isp = 325 sec). The maximum number of satellites the tug could visit was calculated to be 20. The minimum fee for the service was estimated to be $20.48M, and the uncertainty of cost estimations should not exceed $7.5M for the nominal case. The optimal tug for satellite rescue missions was an ion electric spacecraft parked on Earth and controlled via supervision. It was not designed as reusable, and various types of grappling mechanisms or any number of fuel tanks could be attached to it, depending on mission requirements. Both architectures could use a common bus and share the same type of grappling devices. Thesis Supervisor: Olivier de Weck Title: Assistant Professor of Aeronautics and Astronautics and Engineering Systems
Oxidation of carbohydrates and a carbon-13 n.m.r. study of the keto sugars

Three inexpensive oxidation reagents, namely pyridinium chlorochromate, chromium trioxide-dipyridine and nicotinium dichromate were utilized for oxidation of carbohydrates in 78–92% yield. Hydration could be eliminated in the oxidation of pentopyranosides and hexopyranosides, while pentofuranosides had a tendency to be easily hydrated during the oxidation. In the carbon-13 n.m.r. study, the carbonyl function resulted from the oxidation affected on the chemical shifts of α- and β-carbons of methyl 3,4-O-isopropylidene-β-D-arabinopyranosid-2-ulose (8) and 1,2: 4,5-di-O-isopropylidene-β-D-erythro-2,3-hexodiulo-2,6-pyranose (10) to slightly down fields (0.7–2.6 p.p.m.) compared with the chemical shifts before oxidation. While the carbonyl groups of 1,2-O-isopropylidene-5-O-ethyloxycarbonyl-α-D-erythro-pentofuran-3-ulose (4) and methyl 3,5-O-isopropylidene-α-D-threo-pentofuranosid-2-ulose (6) pushed the α-carbons to up fields (3.2–18.3 p.p.m.). However, the order of signals on the spectra before and after oxidation remained unaltered.
Lifecourse Social Conditions and Racial and Ethnic Patterns of Cognitive Aging

A lifecourse perspective is key for understanding and interpreting racial and ethnic patterns in neuropsychological test performance. In this article, we discuss contextual factors that shape the environmental conditions encountered by racial and ethnic minorities in the United States, in particular African-Americans. These conditions include geographic segregation at the level of regions, metropolitan areas, and neighborhoods; intra- and inter-national migration patterns; socioeconomic position, including financial resources, and occupational and educational opportunities; discrimination; and group resources. Each of these exposures sets in course a cascade of individual mediators that ultimately manifest in neuropsychological outcomes. The physiological and behavioral consequences of these pathways likely accumulate across the lifecourse. We focus on cognitive aging, although the processes discussed here begin in infancy and likely influence cognitive outcomes throughout life from childhood into old age. A lifecourse framework can help inform clinical encounters, neuropsychological research, and surveillance regarding the population prevalence of cognitive impairments.
A belief framework for order-of-magnitude reasoning and other qualitative relations

Abstract We present a new framework for the representation of qualitative knowledge and in particular order-of-magnitude relations. The framework is based on the assignment of beliefs to intervals. Generic techniques are proposed for the manipulation of basic-probability densities and belief functions to make inferences. The framework allows a rigorous interpretation of qualitative knowledge without abandoning the informal appeal of intuitive relations. Multiple order-of-magnitude relations can be accommodated and combined for the same pair of quantities. Relations can be propagated to other pairs of quantities; the increasing uncertainty is rigorously modeled, but overlyconservative interpretations that use a single interval for each relation are avoided.
Automatic linear disturbance footprint mapping in Alberta, Canada based on dense time-series Landsat imagery

Mapping linear disturbances from oil and gas extraction and mining in Western Canada traditionally relies on manual digitizing from very high resolution remote sensing data, which usually limits results to small operational area. In this paper, we present an approach of mapping linear disturbances based on time series data analysis of regularly acquired, and low cost satellite data of moderate resolution. This approach involves three steps: line detection based on a multi-scale directional template, line updating based on reappearance frequency and line connection using Hough Transform. This automatic method has been tested over three sites in Alberta, Canada by detecting linear disturbances occurring over the period of 1984-2013 using Landsat imagery. The results show that the method can extract very narrow linear features, including seismic lines, roads and pipelines with a good performance.
Carotid artery mixing with diastole-phased pulsed drug infusion

Focal injury to the brain or retina is a frequent complication of drug delivery to the internal carotid artery (ICA) and may be due to poor mixing of the drug with blood at the infusion site. Rhesus monkeys were studied to determine whether phased drug delivery during diastole from a modified pulsatile angiographic injector would improve drug mixing in vivo. A radiolabeled flow tracer, carbon-14-iodoantipyrine (14C-IAP), was injected into the ICA of three monkeys in 80-msec pulses, each ending at least 50 msec before the end of local diastole. Local isotope concentration in the brain was determined by quantitative autoradiography. The ratio of highest to lowest concentration was 1.86 +/- 0.26 (mean +/- standard deviation) in the frontoparietal cortex, 1.65 +/- 0.42 in the frontoparietal white matter, 1.89 +/- 0.28 in the temporal cortex, and 1.39 +/- 0.17 in the basal ganglia. These results were similar to recordings in three control animals that received intravenous 14C-IAP to demonstrate complete drug mixing (1.37 +/- 0.12, 1.41 +/- 0.11, 1.70 +/- 0.08, 1.22 +/- 0.24, respectively), and contrasted to findings in five animals which received continuous intracarotid infusions to demonstrate standard ICA drug delivery (4.54 +/- 2.07, 2.94 +/- 1.45, 5.43 +/- 3.57, 3.60 +/- 2.90, respectively). Pulsed intra-arterial infusion during diastole provides a technically simple method for improving intravascular drug mixing, and results in drug delivery to tissue capillaries that is proportional to blood flow.
On Post-Hoc Blocking

Post-hoc blocking and the analysis of covariance (ANCOVA) are two alternative procedures that employ a concomitant variable as a means of increasing statistical power relative to the completely ran...
The Impact of Minimum Lot Size Regulations On House Prices in Eastern Massachusetts

Abstract There has been an increased focus on zoning as a cause of high house prices in many metropolitan areas in the United States. But isolating the direct causal impact of zoning on house prices is difficult. This study overcomes the problems in the existing literature by investigating the effect of minimum lot size restrictions (MLRs) on house prices using data on transactions of single-family homes in the greater Boston area from 1987 to 2006. We estimate a model of house prices that include changes in minimum lot size at the zoning district level, variables that account for possible spillover effects in the same town and in nearby towns, and zoning district fixed effects. We estimate price effects due to MLR of 20% or more at the upper end of the impact distribution. We find evidence of significant spillover effects within towns that are similar to those in the zoning district in which the MLR changed. The impact on house prices in nearby towns is significant and as high as 5%. Finally, we find that the impact increases over time with effects as large as 40% occurring 10 years after the change in MLR.