cssi/SciSciGPT-SciSciNet huggingface dataset:
Integrating Vision and Touch

The vision and tactile processing described in the previous chapters needs to be integrated to build 3-D descriptions of surfaces and features of objects that can be matched against the models in the model data base. The procedures described in this chapter use both sensing modalities, integrating the data from the sensors to build high level descriptions of what is seen and felt. The first integration procedure is a hierarchical procedure for building curvature-continuous composite surfaces from the vision and touch data. This procedure computes a Coons’ patch representation which is the same primitive used in the model data base, facilitating matching between the sensed objects and the models. The second procedure is a method for creating smoothed boundaries of hole and cavity cross sections using both vision and touch which is accurate and also useful for matching.
PESTICINS II. I and II Production of Pesticin

Abstract Brubaker, Robert R. (Fort Detrick, Frederick, Md.) and Michael J. Surgalla. Pesticins. II. Production of pesticin I and II. J. Bacteriol. 84:539–545. 1962.—Pesticin I was separated from pesticin I inhibitor by ion-exchange chromatography of cell-free culture supernatant fluids and by acid precipitation of soluble preparations obtained from mechanically disrupted cells. The latter procedure resulted in formation of an insoluble pesticin I complex which, upon removal by centrifugation and subsequent dissolution in neutral buffer, exhibited a 100- to 1,000-fold increase in antibacterial activity over that originally observed. However, activity returned to the former level upon addition of the acid-soluble fraction, which contained pesticin I inhibitor. Since the presence of pesticin I inhibitor leads to serious errors in the determination of pesticin I, an assay medium containing ethylenediaminetetraacetic acid in excess Ca++ was developed; this medium eliminated the effect of the inhibitor. By use of the above medium, sufficient pesticin I was found to be contained within 500 nonirradiated cells to inhibit growth of a suitable indicator strain; at least 107 cells were required to effect a corresponding inhibition by pesticin II. Although both pesticins are located primarily within the cell during growth, pesticin I may arise extracellularly during storage of static cells. Slightly higher activity of pesticin I inhibitor was found in culture supernatant fluids than occurred in corresponding cell extracts of equal volume. The differences and similarities between pesticin I and some known bacteriocins are discussed.
Reconstruction of Patterns from Noisy Inputs Using Morphological Associative Memories

Morphological neural networks are based on a new paradigm for neural computing. Instead of adding the products of neural values and corresponding synaptic weights, the basic neural computation in a morphological neuron takes the maximum or minimum of the sums of neural values and their corresponding synaptic weights. By taking the maximum (or minimum) of sums instead of the sum of products, morphological neuron computation is nonlinear before thresholding. As a consequence, the properties of morphological neural networks are drastically different than those of traditional neural network models. In this paper we restrict our attention to morphological associative memories. After a brief review of morphological neural computing and a short discussion about the properties of morphological associative memories, we present new methodologies and associated theorems for retrieving complete stored patterns from noisy or incomplete patterns using morphological associative memories. These methodologies are derived from the notions of morphological independence, strong independence, minimal representations of patterns vectors, and kernels. Several examples are provided in order to illuminate these novel concepts.
Recent Palladium Membrane Reactor Development at the Tritium Systems Test Assembly

The palladium membrane reactor (PMR) is proving to be a simple and effective means for recovering hydrogen isotopes from fusion fuel impurities such as methane and water. This device directly combines two techniques which have long been utilized for hydrogen processing, namely catalytic shift reactions and palladium/silver permeators. A proof-of-principle (PMR) has been constructed and tested at the Tritium Systems Test Assembly of Los Alamos National Laboratory. The first tests with this device showed that is was effective for the proposed purpose. Initial work concluded that a nickel catalyst was an appropriate choice for use in a PMR. More detailed testing of the PMR with such a catalyst was performed and reported in other works. It was shown that a nickel catalyst-packed PMR did, indeed, recover hydrogen from water and methane with efficiencies approaching 100% in a single processing pass. These experiments were conducted over an extended period of time and no failure or need for regeneration was encountered. These positive results have prompted further PMR development. Topics addressed include alternate PMR geometries and initial testing of the PMR with tritium. These are the subjects of this paper.
Safeguarding Fundamental Rights: Judicial Incursion into Legislative Authority

This article claims that congressional authority over civil rights is linked to an American rights-based tradition. It traces that tradition from the Revolution, through Reconstruction, and onto today. Contrary to scholars like Rogers Smith and Larry Yackle, I claim that a fairly stable national ethos, which can be traced to the founding documents, has played a vital role in centuries of civil rights development. The principle of liberal equality, lying at the core of the Fourteenth Amendment, is essential to developing national civil rights policies. Part II of the article discusses the concepts of liberty and equality during the revolutionary period. Emphasis is given to the early understanding of the national statements of purpose in the Declaration of Independence and the Preamble to the Constitution. That part also discusses the constitutional compromises that failed to achieve the stated ends of national government. Part III turns to several abolitionist views on the existence of a national obligation to protect rights. Those constitutional theories became influential during debates on the ratification of the Reconstruction Amendments, which granted Congress the power to pass laws securing rights intrinsic to national citizenship against arbitrary abuses. Debates on the Thirteenth and Fourteenth Amendments, the subjects of Part IV, made the principle of equal rights enforceable through federal statutes. As Part V recounts, the Court variously restrained the reach of new congressional powers. The article concludes, in part VI, with a critique of recent Supreme Court decisions, such as United States v. Morrison and Board of Trustees v. Garrett, which have further limited congressional civil rights authority.
The Secret Life of Pronouns: What Our Words Say About Us

Discovering the secret life of the most forgettable words -- Ignoring the content, celebrating the style -- The words of sex, age, and power -- Personality: finding the person within -- Emotion detection -- Lying words -- The language of status, power, and leadership -- The language of love -- Seeing groups, companies, and communities through their words -- Word sleuthing -- Appendix: a handy guide for spotting and interpreting function words in the wild.
Health promotion for pregnant adolescents.

While the Centers for Disease Control and Prevention continue to report declining pregnancy rates among teenagers the incidence of adolescent pregnancy is still of major significance with nearly one million adolescent girls becoming pregnant each year. In 1999 the last year for which data are available there were: 312186 births among adolescents ages 18 to 19; 163559 births among girls 15 to 17 years of age; and 9049 births among girls 14 years old and younger While these numbers do represent a several year decrease the numbers are still of significant concern to nurses and other health care providers who care for these young women. (excerpt)
A Teacher's Journey with a New Generation Handheld: Decisions, Struggles, and Accomplishments.

In this technology-oriented age, teachers face daily decisions regarding the use of advanced digital technologies—graphing calculators, dynamic geometry software, blogs, wikis, podcasts and the like—to enhance student mathematical understanding in their classrooms. In this case study, the authors use the Technological, Pedagogical, and Content Knowledge (TPACK) model in conjunction with a five-stage developmental model, which can be used to describe growth in TPACK to describe the initial attempts of a teacher, Jane, to develop TPACK as she learns and attempts to integrate an advanced teaching technology into her classroom, namely the TI-Nspire graphing calculator. The study tracks her struggles to reconcile some traditional beliefs about how students learn with her desire to be responsive to what she perceives as affordances of advanced digital technologies. Main data collection methods were journal writing, observations, document analysis, and interviews. Using the five-stage developmental model, we saw that this experience helped Jane to move among different stages. This study showed that the TPACK model with the five-stage developmental model can be a beneficial tool for researchers to study teachers' professional growth and is also a valuable tool for teachers to reflect on their own growth.
A Versatile Prism: Assessing Procurement Law Through the Principal-Agent Model

Over the past several decades, the federal procurement system in the United States has grown remarkably, and now totals over $500 billion annually. Over that same period, the rules governing federal procurement have been buffeted by broad efforts at reform. At no point, however, have we ever had an overarching theory - a model or prism - through which to assess the procurement system or its reform. Agency theory provides one such theoretical model. Long established in economics and the other social sciences, the principal-agent model (agency theory) provides a model to explain successes (and failures) in organizational structures, and also to understand the procurement system and its rules. The theory builds upon the classic principal-agent model. A principal enlists an agent to carry out the principal’s goals, presumably because the agent enjoys some comparative advantage in performing the goals. Inevitably, however, the agent’s interests diverge from the principal’s; if the agent’s goals diverge sufficiently, the agent may be said to have a conflict of interest. This article employs agency theory to assess classic constructs of procurement law, such as Steven Schooner's desiderata, and argues that the theory can be used to solve future puzzles in procurement policy, and to predict where procurement policies are likely to fail - and to succeed.
Expression of Arabidopsis NPR1 in Transgenic Cotton Confers Resistance to Non‐defoliating Isolates of Verticillium dahliae but not the Defoliating Isolates

Verticillium wilt, caused by Verticillium dahliae Kleb., causes severe yield and quality losses in most cotton growing areas of the world. Only moderate resistance has been achieved by traditional breeding. Therefore, transgenic approaches offer a possible alternative to obtain resistance against this disease. Overexpression of a homologous or heterologous NPR1 gene has been effective in conferring broad-spectrum resistance to diverse pathogens in a variety of plants. We investigated the resistance of cotton plants, expressing the Arabidopsis NPR1 (ATNPR1) gene, to defoliating and non-defoliating pathotypes of V. dahliae. The transgenic cotton plants showed significant resistance against two non-defoliating V. dahliae isolates. Both visual symptoms and pathogen colonization were reduced, indicating that disease progression was curtailed in the AtNPR1-transformants. In contrast, the same transgenic lines showed little, if any, resistance to two defoliating isolates. The NPR1-mediated activation of cotton's defences apparently is not sufficient to counter the disease mechanism(s) utilized by the defoliating pathotype of V. dahliae.
Takeovers in the Ivory Tower: How Academics are Learning Martin Lipton May be Right

In 1979 Martin Lipton published an essay arguing that corporate law gives directors and not shareholders the authority to decide whether a company should sell itself at a premium, and that this is a good arrangement for both shareholders and society. After years of vocal disagreement many academics are starting to suspect that Martin Lipton was right. Much of the academic hostility that initially greeted Lipton's claim was based on two important ideas in finance economics: efficient market theory and the "principal-agent" model of the public corporation. Scholars recently have begun to examine each of these ideas more closely. Neither is holding up especially well. New theories are being developed to explain important aspects of securities markets and corporate law that cannot be explained by efficient market theory and the principal-agent model. These new theories suggest the practitioner may have been correct: maximizing share price is not always in the best interest of society, the firm, or the shareholders themselves.
Do long delay conditioned stimuli develop inhibitory properties

In long-delay conditioning, a long conditioned stimulus (CS) is paired in its final segments with an unconditioned stimulus. With sufficient training, this procedure usually results in conditioned responding being delayed until the final segment of the CS, a pattern of responding known as inhibition of delay. However, there have been no systematic investigations of the associative structure of long delay conditioning, and whether the initial segment of a long delay CS actually becomes inhibitory is debatable. In an appetitive preparation with rat subjects, the initial segment of long delay CS A passed a retardation (Experiment 1a) but not a summation (Experiment 1b) test for conditioned inhibition. Furthermore, retardation was observed only if long delay conditioning and retardation training occurred in the same context (Experiment 2). Thus, the initial segment of a long delay CS appears to share more characteristics with a latent inhibitor than a conditioned inhibitor. Componential theories of conditioning appear best suited to account for these results.
Draft Genome Sequence of Citrobacter rodentium DBS100 (ATCC 51459), a Primary Model of Enterohemorrhagic Escherichia coli Virulence.

ABSTRACT Citrobacter rodentium is a Gram-negative bacterium which causes transmissible murine colonic hyperplasia and models the virulence of enterohemorrhagic Escherichia coliin vivo. Thus, C. rodentium is used to study human gastrointestinal disease. We present the draft genome sequence of C. rodentium strain ATCC 51459, also known as DBS100.
Carotid Artery Dissection due to Elongated Styloid Process: A Self‐Stabbing Phenomenon

Elongated styloid process (ESP) is an anatomical variant that has been described as the cause of Eagle syndrome. Until recently, the styloid process has not been appreciated as a significant contributor to carotid artery dissection (CAD), which is not part of Eagle syndrome. We present a case of a 41-year-old male who presented with acute right middle cerebral artery occlusion and was found to have ESP projecting to and abutting the lateral wall of a dissected right internal carotid artery (ICA). Forced sustained head turning with maximal muscle contraction was the initiating event driving the styloid process into the wall of the ICA in a manner that can be likened to being stabbed with a pointed object. Knowing the association between ESP, Eagle syndrome, and CAD shall lead to increased awareness and appropriate diagnosis and treatment.
Characterization of human immunodeficiency virus type 1 integrase expressed in Escherichia coli and analysis of variants with amino-terminal mutations.

Abstract Replication of a retroviral genome depends upon integration of the viral DNA into a chromosome of the host cell. The integration reaction is mediated by integrase, a viral enzyme. Human immunodeficiency virus type 1 integrase was expressed in Escherichia coli and purified to near homogeneity. Optimum conditions for the integration and 3'-end-processing activities of integrase were characterized by using an in vitro assay with short, double-stranded oligonucleotide substrates. Mutants containing amino acid substitutions within the HHCC region, defined by phylogenetically conserved pairs of histidine and cysteine residues near the N terminus, were constructed and characterized by using three assays: 3'-end processing, integration, and the reverse of the integration reaction (or disintegration). Mutations in the conserved histidine and cysteine residues abolished both integration and processing activities. Weak activity in both assays was retained by two other mutants containing substitutions for less highly conserved amino acids in this region. All mutants retained activity in the disintegration assay, implying that the active site for DNA cleavage-ligation is not located in this domain and that the HHCC region is not the sole DNA-binding domain in the protein. However, the preferential impairment of processing and integration rather than disintegration by mutations in the HHCC region is consistent with a role for this domain in recognizing features of the viral DNA. This hypothesis is supported by the results of disintegration assays performed with altered substrates. The results support a model involving separate viral and target DNA-binding sites on integrase.
Synthesis and characterization of borane adducts of some diazines

Borane adducts of pyridazine, pyrimidine and pyrazine and some of its methyl derivatives have been synthesized and characterized by elemental analyses, infrared spectral data, and 1H and 11B nuclear magnetic resonance spectral data. The adducts of the pyrazines and pyrimidine were found to contain two mol of BH3 whereas only one mol of BH3 was found with pyridazine. The 11B NMR chemical shift of the pyrazine adducts was found to contain two mol of BH3 whereas only one mol with δ11B (ppm) = −29.6 + a(−1.8) + b = (−0.4) + c + d, in which a represents the number of methyl groups ortho to the nitrogen donor atom and b represents the number of methyl groups meta to the nitrogen donor atom. Terms c and d have values only when two or more methyl groups are present. Term c represents the effect of two methyl groups ortho to the nitrogen donor atom and d represents two cis-methyl groups which are ortho and meta to the nitrogen donor (e.g., 2,3-dimethylpyrazine). To our knowledge, this is the first correlation of 11B chemical shift data for the effect of substituents on a boronnitrogen bond.
Bipolar Pathophysiology and Development of Improved Treatments

The purpose of this review is to provide strategies and their rationale which can facilitate scientifically productive investigations into genetic, neuronal, brain functional and clinical aspects of bipolar disorder. The presentation addresses both factors that have impeded and those that have facilitated landmark advances on the pathophysiology and treatment of bipolar disorders. Application of the strategies can provide a scientific platform that may be useful to basic and clinical scientists for the purposes of achieving seminal advances in understanding pathophysiology, including inherited and experience based contributors to disease expression. Current diagnostic criteria omit certain key symptoms, do not include illness course or family history and lack specification of the importance of fundamental symptomatology. Consideration of such factors in inclusion and exclusion criteria, and in assessment instruments in basic and clinical studies, serves to strengthen the capability of a research plan to test key hypotheses regarding moderating and mediating factors of this complex illness. For example, most studies of brain structure and function and of new interventions have selected subjects on the basis of traditional full syndromal criteria. Evidence indicates that additional consideration of principal behavioral domains of bipolar symptomatology, e.g., anxiety, psychosis, impulsivity, elevated psychomotor and cognitive processing speed, rather than strictly depressive or manic syndromes can provide more homogeneous samples for study, and increase the focus of experimental hypotheses.
Direct Determination of Wave-Lengths from Fabry-Perot Interferometer Patterns

A new type of measuring and computing engine has been constructed which determines wave-lengths and wave numbers directly from spectrograms made by crossing the dispersion of a Fabry-Perot interferometer with that of a concave diffraction grating. The wave-length of a spectrum line is first determined to six figures from the grating dispersion by the method used in the author’s automatic comparator, and this wave-length is then converted to wave number by a mechanical continuous-function computing arrangement. The thickness of the etalon separator used having been pre-set into the machine, all wave-lengths are automatically divided into twice this thickness to give on dials the order of interference corresponding to the instantaneous wave-length setting of the comparator. The interference pattern of each spectrum line is projected on a screen in front of the operator with a magnification proportional to the square root of the order of interference, and falls on a set of parabolic fiducial lines drawn to fit the optical system used to project the interference fringes on the slit of the grating spectrograph. The operator moves the screen carrying these parabolic lines up or down until they coincide with the density maxima of the interference pattern; the partial order of interference ∊ in the center of the pattern can then be read to three figures from a dial. By turning the plate control handle of the machine slightly the operator then makes the ∊ reading of the machine coincide with that of this dial; cams having introduced corrections for the dispersion of air and the variation of phase change with wave-length, the dials then give the wave-length and wave number of the line correctly to seven or eight figures, depending on its sharpness. The speed of reduction of Fabry-Perot patterns is by this means increased at least 20-fold over that of previous methods, and the precision of setting appears to be considerably improved also. Repeat readings on sharp lines are found consistent to within a few ten-thousandths of an angstrom. The precision of the wave-length values obtained is limited principally by the diffuseness of the interference pattern arising from the breadth of a line.Improvements now under development include automatic photoelectric scanning of interferometer patterns, and the direct recording by an electric typewriter of eight-figure wave-length and wave-number values for each line. The new device is being used to determine standard wave-lengths needed for the more effective utilization of the original automatic comparator.
SpeedHap: An Accurate Heuristic for the Single Individual SNP Haplotyping Problem with Many Gaps, High Reading Error Rate and Low Coverage

Single nucleotide polymorphism (SNP) is the most frequent form of DNA variation. The set of SNP's present in a chromosome (called the em haplotype) is of interest in a wide area of applications in molecular biology and biomedicine, including diagnostic and medical therapy. In this paper we propose a new heuristic method for the problem of haplotype reconstruction for (portions of) a pair of homologous human chromosomes from a single individual (SIH). The problem is well known in literature and exact algorithms have been proposed for the case when no (or few) gaps are allowed in the input fragments. These algorithms, though exact and of polynomial complexity, are slow in practice. When gaps are considered no exact method of polynomial complexity is known. The problem is also hard to approximate with guarantees. Therefore fast heuristics have been proposed. In this paper we describe SpeedHap, a new heuristic method that is able to tackle the case of many gapped fragments and retains its effectiveness even when the input fragments have high rate of reading errors (up to 20%) and low coverage (as low as 3). We test SpeedHap on real data from the HapMap Project.
THE WEALTH EFFECTS OF INCOME INSURANCE

Precautionary savings models suggest that wealth should rise with income risk. Risk is reduced by means-tested transfers, however, which implies that transfer programs should discourage private wealth accumulation. We offer a comprehensive empirical assessment based on variation across states in the generosity of a number of programs, specifically unemployment insurance and means-tested transfers (Aid to Families with Dependent Children and Food Stamps). We use monthly data on married couples from the Survey of Income and Program Participation (SIPP) to regress wealth on income, income risk, and various measures of transfer generosity. The results support the precaution-ary savings model and reveal moderate negative wealth effects of both unemployment insurance and means-tested transfers, with an elasticity of about −0.18.
Posttranslational processing of SREBP-1 in rat hepatocytes is regulated by insulin and cAMP

Insulin and cAMP have opposing effects on de novo fatty acid synthesis in liver and in cultured hepatocytes mediated by sterol-regulatory element binding protein (SREBP). To determine whether these agents regulate the cleavage of full-length SREBP to generate the transcriptionally active N-terminal fragment (nSREBP) in primary rat hepatocytes, an adenoviral vector (Ad-SREBP-1a) was constructed to constitutively express full-length SREBP-1a. Insulin increased, and dibutyryl (db)-cAMP inhibited, generation of nSREBP-1a from its full-length precursor. Insulin stimulated processing of SREBP-1a within 1h, and the effect was sustained for at least 24h. The initial stimulation of SREBP processing by insulin preceded measurable reduction in Insig-2 mRNA levels. Rat hepatocytes were also infected with an adenovirus expressing the nuclear form of SREBP-1c (Ad-nSREBP-1c). Insulin increased the half-life of constitutively expressed nSREBP-1c, and this effect of insulin was also inhibited by db-cAMP.
Construction of almost automorphic symbolic minimal flows

Abstract This paper is concerned with the description of almost automorphic symbolic minimal flows in terms of particular closed covers of their maximal equicontinuous factors. It is shown that every almost automorphic symbolic minimal flow arises from a separating cover of its maximal equicontinuous factor; and that every compact metric monothetic group occurs as the maximal equicontinuous factor of an almost automorphic symbolic minimal flow on two symbols.
The effect of prolonged storage of cell cultures in dimethyl sulfoxide and glycerol prior to freezing.

Summary Two tissue culture cell lines, HeLa and WI-38, were stored in the presence of 5% DMSO or 5% glycerol for intervals of 24 to 168 hrs at 4 and 37°C to test the toxic effects of these additives on the cells. The studies demonstrated the superiority of storage at 4°C. Viability was reduced after 72 hrs of storage of HeLa cells at 4°C and 24 hrs at 4°C was found to be the maximal storage time without toxic effects. During this time interval no demonstrable loss of viability was observed as monitored by the cell permeability and cell adhesion tests in either the frozen or unfrozen cells. Cell damage of the more delicate WI-38 cells was observed after 24 hrs at 4°C in both the prefreeze and post-thaw cultures; 6 hrs was the maximal storage period at 4°C without loss of viability. We recommend from the results of these studies that the cell lines be stored at 4°C when they cannot be immediately frozen after ampulizing. It is suggested that the more delicate diploid and primary cell cultures must be frozen within 3 to 6 hrs of ampulizing. Although the more hardy established cell lines may be left overnight at 4°C and successfully frozen on the next day with little loss in viability, it is advisable to freeze them within several hours after ampulizing to minimize cell damage.
DUSP1 Phosphatase Regulates the Proinflammatory Milieu in Head and Neck Squamous Cell Carcinoma

DUSP1 is a dual-specificity phosphatase that regulates mitogen-activated protein (MAP) kinase activity. Studies have associated loss of DUSP1 expression with certain cancers, but there has been no report of a mechanism by which this supports tumor progression. In this study, we found DUSP1 mRNA and protein decreased in human head and neck squamous cell carcinoma tissues compared with adjacent nontumor controls. To evaluate the impact of this difference, we compared the susceptibility of Dusp1-deficient mice with oral squamous carcinogenesis induced by 4-nitroquinoline 1-oxide. Dusp1-deficient mice displayed enhanced disease progression, characterized by advanced onset, histologic stage, and tumor burden. In a syngeneic model of tumor progression, subcutaneous injection of EO771 cells formed faster-growing tumors in Dusp1-deficient mice, an effect abrogated by inhibition of p38 MAP kinase with SB203580. Histologic and quantitative assessments demonstrated increased inflammation and deregulated chemokine and cytokine expression in Dusp1-deficient tumor tissues. Specifically, proinflammatory cytokine IL1β was elevated. IL1β production was recapitulated ex vivo in primary bone marrow-derived macrophages from Dusp1-deficient mice. Together, our results clearly establish the role of Dusp1 as a tumor suppressor gene that regulates cancer-associated inflammation.
Static Light Scattering from Mixtures of Polyelectrolytes in Low Ionic Strength Solutions

Static light scattering behavior is explored for salt-free and low ionic strength solutions of pure, highly charged polyelectrolytes and polyelectrolyte mixtures at very low concentration (10 -5 g/mL). The pure polyanions (xanthan and proteoglycan subunits) show pronounced, high-contrast angular scattering peaks in the scattering function I(q), whereas hyaluronate shows none. When I(q) is divided by the experimentally extrapolated form factor P(q) to obtain the structure function S(q) using I(q) P(q) S(q), a high-contrast peak remains in S(q). This can be interpreted in terms of a quasi-periodic, screened (i.e. damped) pair correlation functiong(r), which suggests that the peak is measuring an average interparticle separation and not any type of electrostatic scaling length. The particle/particle correlations are thought to be dynamic in the sense that no crystallization or local static ordering takes place. Adding neutral polymer (dextran) causes marked changes inI(q) which can be rationalized in terms of an absence of correlation between xanthan and the polymer. Adding polyanions (hyaluronate or polystyrenesulfonate) to xanthan produces a completely different change in I(q), which suggest that the xanthan molecules are being locally concentrated.
Effect of nucleosome distortion on the linking deficiency in relaxed minichromosomes.

Abstract The wrapping of closed circular DNA on a protein surface, followed by relaxation with a topoisomerase and removal of proteins, produces a characteristic DNA linking deficiency, ΔLk . We show that the magnitude of ΔLk depends upon the surface shape, and we calculate changes in ΔLk caused by particular distortions of the protein wrapping surface. If the DNA remains attached to the surface during distortion, the DNA winding number, Φ, is not altered. The change in ΔLk is then equal to the change in the surface linking number, SLk , which is a straightforward measure of the wrapping of the DNA around the surface. For left-handed wrapping, as in a nucleosome, SLk = − n , the number of times that the DNA axis winds around the axis of the protein complex. We calculate values of SLk for the helical wrapping of a constant length of DNA on protein surfaces having the shapes of cylinders and of ellipsoids and hyperboloids of revolution. If the equatorial radius of the protein is fixed, change in shape from a cylinder to a hyperboloid increases SLk , while the corresponding change to an ellipsoid reduces SLk . We apply the general results to the interpretation of experiments in which minichromosomes are relaxed with topoisomerase at various temperatures and ΔLk is determined. The result is that a distortion of the nucleosome core by at most 5 % (the change in the radius at the axial extremity relative to the equator) is sufficient to explain the observed ΔLk changes.
Maltreatment of children with developmental disabilities: An ecological systems analysis

Abstract The purpose of this review is to understand the risk factors for maltreatment of children with developmental disabilities. Using the Bronfrenbrenner's (1976, 1977) ecological systems framework, the authors examine how socio-demographic characteristics (age, gender, and special education), micro - (parent–child relationship and domestic violence), exo - (parenting stress, parents' social support, and area of residence), and macro systems level (culturally defined parenting practices) factors influence or inhibit maltreatment of children with disabilities. The authors highlight major implications for practice and policy for maltreated children with disabilities.
Peering inside the black box to find enzyme-bound intermediates.

The NMR structures of three intermediates bound to the pyridoxal-synthesizing enzyme Pdx1 illuminate its complex catalytic cycle. The success of this approach with a high-molecular-weight protein should encourage further applications of NMR techniques for characterizing enzyme reaction pathways.
The growth enhancing effects of allograft inflammatory Factor-1 (AIF-1) in VSMC are dose-dependent and mediated by its ability to bind calcium

Background: Vasculopathy subsequent to allograft rejection often leads to vascular smooth muscle cell (VSMC) activation resulting in oblerative hyperplasia. Allograft Inflammatory Factor-1 (AIF-1) is an intracellular calcium-binding protein which is expressed in coronary arteries of human transplant recipients with coronary allograft vasculopathy (CAV). The purpose of this study was to determine how this molecule influences the growth of VSMCs. We stably transfected AIF-1cDNA into rat VSMC and selected individual colonies based on differing amounts of AIF-1 expression. These clones were then examined for their ability to modulate proliferation of VSMC. The results of these experiments show that all AIF-1 expressing clones grow more rapidly than do control cells, and the doubling time of these cells is inversely correlated with the level of AIF-1 expressed. AIF-1 expressing cells also show a more rapid progression through the cell cycle, as determined by flow cytometry, and an enhanced expression of the cell cycle proteins PCNA, cyclin A, and cyclin B, versus control cells, as examined by western analysis. We modified the calcium binding motif of AIF-1 by site-directed mutagenesis to create one mutant deficient in calcium-binding and one mutant with enhanced calcium-binding characteristics relative to wild-type AIF-1. The cDNA for each of these mutants was stably transfected into VSMC and their growth enhancing characteristics examined. Neither of these two mutants are capable of enhancing VSMC growth as compared with wild-type AIF-1. This is not due to differences in the amount of AIF-1 expressed in the cells as determined by western analysis. Conclusions: This work suggests that 1constitutive AIF-1 expression induces enhanced VSMC growth and expression of cell cycle proteins, 2there is a relationship between the degree of growth enhancement and the amount of AIF-1 expression in these cells, and, 3these AIF-1 growth enhancing effects may be mediated by its ability to bind calcium.
Multiscale molecular dynamics using the matched interface and boundary method

The Poisson-Boltzmann (PB) equation is an established multiscale model for electrostatic analysis of biomolecules and other dielectric systems. PB based molecular dynamics (MD) approach has a potential to tackle large biological systems. Obstacles that hinder the current development of PB based MD methods are concerns in accuracy, stability, efficiency and reliability. The presence of complex solvent-solute interface, geometric singularities and charge singularities leads to challenges in the numerical solution of the PB equation and electrostatic force evaluation in PB based MD methods. Recently, the matched interface and boundary (MIB) method has been utilized to develop the first second order accurate PB solver that is numerically stable in dealing with discontinuous dielectric coefficients, complex geometric singularities and singular source charges. The present work develops the PB based MD approach using the MIB method. New formulation of electrostatic forces is derived to allow the use of sharp molecular surfaces. Accurate reaction field forces are obtained by directly differentiating the electrostatic potential. Dielectric boundary forces are evaluated at the solvent-solute interface using an accurate Cartesian-grid surface integration method. The electrostatic forces located at reentrant surfaces are appropriately assigned to related atoms. Extensive numerical tests are carried out to validate the accuracy and stability of the present electrostatic force calculation. The new PB based MD method is implemented in conjunction with the AMBER package. MIB based MD simulations of biomolecules are demonstrated via a few example systems.
Phagocyte-like NADPH oxidase [Nox2] in cellular dysfunction in models of glucolipotoxicity and diabetes

Increased intracellular generation of reactive oxygen species [ROS] has been implicated in the pathology of metabolic [diabetes] and neurodegenerative [Alzheimer's] diseases. Accumulating evidence suggests NADPH oxidases [Noxs] as the principal source for cellular ROS in humans. Of this class of enzymes, the phagocyte-like Nox [Nox2] has come under intense scrutiny as one of the "culprits" for the induction of cellular damage culminating in the onset of diabetes and its complications. Functional regulation of Nox2 is fairly complex due to its membranous [gp91(phox), p22(phox)] and cytosolic [p40(phox), p47(phox), p67(phox) and Rac1] cores, which require specific post-translational modification steps [phosphorylation and lipidation] for their membrane association. Therefore, optimal efficacy of Nox2 depends upon precise regulation of these signaling steps followed by translocation of the cytosolic components to the membrane. Interestingly, numerous recent studies have reported sustained activation of Nox2, ROS-derived oxidative stress, and cellular dysfunction in in vitro and in vivo models of glucolipotoxicity and diabetes. These investigations employed a variety of cell-permeable peptides and pharmacological inhibitors to impede Nox2 holoenzyme assembly and activation in pancreatic islet β-cells, cardiomyocytes and retinal endothelial cells under conditions of glucolipotoxicity and diabetes. Herein, we highlight the existing evidence to implicate Nox2 as the "trigger" of cellular damage, and identify critical gaps in our current understanding that need to be addressed to further affirm the roles of Nox2 as a potential therapeutic target for the treatment of diabetes and other metabolic disorders.
Observations on the sterile whorls ofAcetabularia

The sterile whorls ofAcetabularia increase greatly the surface area of the cell. These structures function in the uptake of solutes from the environment. The development of the whorls is controlled by light and also by the availability of nutrients.
Investigation of reagent distributions on glass fiber membrane filters used in air sampling.

This project has arisen from the need to produce GFFs (glass fiber filters) bearing a thin and evenly distributed coating of a selected reagent in the equatorial plane for breakthrough studies. However, it has been discovered that today’s two general techniques for coating GFFs (total immersion and application of reagent solution to GFFs) have usually produced unevenly distributed coatings of reagent in the equatorial plane. In addition, quantities of reagent on GFFs from commercial sources may vary widely in the same lot of coated GFFs. Consequences are variability in capacity of coated filters at the point of breakthrough and, perhaps, wasted reagent. Although today’s reagent-coated filters may be satisfactory for routine air sampling, such filters may be unacceptable for precise breakthrough studies. Research has been conducted successfully to produce nearly evenly distributed coatings of reagents in the equatorial plane of GFFs by application of reagent solutions to the centers of GFFs which are resting on crisscrossing, fine, stainless-steel wire. Distributions of coatings have been determined by punching out twenty-one 5-mm circles from each GFF and analyzing each circle by flow-injection with a UV detector. Lowest achievable relative standard deviations of measurement (RSDs) for reagents in 5-mm circles have been 5 to 7%. Reagents studied have included 1-(2-pyridyl)piperazine (1-2PP), 2,4-dinitrophenylhydrazine (DNPH), and 1-(9-anthracenylmethyl)piperazine (MAP). Factors affecting the distribution of such coatings include choice of reagent and choice of solvent for the reagent solution.
Large vestibular aqueduct syndrome and endolymphatic hydrops: two presentations of a common primary inner-ear dysfunction?

Objective To present the theory that large vestibular aqueduct syndrome (i.e. the recognised existence of an enlarged vestibular aqueduct with progressive sensorineural hearing loss) and endolymphatic hydrops are due to a common primary dysfunction of inner-ear fluid homeostasis. Method Case report and review of the world literature concerning large vestibular aqueduct syndrome and endolymphatic hydrops. Results We report a family in which one sibling suffered from large vestibular aqueduct syndrome while the other had classic Meniere's disease. This suggests that large vestibular aqueduct syndrome and endolymphatic hydrops, in some cases, may be due to a common primary dysfunction of inner-ear fluid homeostasis. Conclusion To our knowledge, this is the first report in the world literature to postulate that variation in the relative compliance of inner-ear membranes could be the factor that determines the manifestation of the disorder as either endolymphatic hydrops or large vestibular aqueduct syndrome.
1. NARRATIVE EXPLANATION AND ITS MALCONTENTS

In this paper I look at narrative as a mode of explanation and at various ways in which the explanatory value of narrative has been criticized. I begin with the roots of narrative explanation in everyday action, experience, and discourse, illustrating it with the help of a simple example. I try to show how narrative explanation is transformed and complicated by circumstances that take us beyond the everyday into such realms as jurisprudence, journalism, and history. I give an account of why narrative explanation normally satisfies us, and how or in what sense it actually explains. Then I consider how narrative is challenged and rejected as a mode of explanation in many scientific and other contexts and why attempts are made to replace it with something else. I try to evaluate the nature and sources of these challenges, and I describe this controversy over narrative against the historical background of its emergence. My paper ends with a pragmatic defense of narrative explanation against these challenges.
Far ultraviolet atomic and molecular nitrogen emissions in the dayglow

A scanning spectrophotometer was used to observe the far ultraviolet day airglow between 1130 and 1520 A at 4.4-A spectral resolution. Fourteen bands of the N2 Lyman-Birge-Hopfield (LBH) system are clearly resolved and suggest a total LBH system zenith column emission rate of 3810 plus or minus 520 R extrapolated to the subsolar point. A photoelectron flux model (based on recent photoelectron flux measurements and the observed LBH altitude profile) is used to derive the direct and dissociative excitation contributions to the atomic nitrogen emissions. The calculated atomic nitrogen density agrees with other measurements, although it is an order of magnitude greater than previous photochemical model results.
Effect of elevated potassium on the ion content of mouse astrocytes and neurons

Potassium is tightly regulated within the extracellular compartment of the brain. Nonetheless, it can increase 3- to 4-fold during periods of intense seizure activity and 10- to 20-fold under certain pathological conditions such as spreading depression. Within the central nervous system, neurons and astrocytes are both affected by shifts in the extracellular concentration of potassium. Elevated potassium can lead to a redistribution of other ions (e.g., calcium, sodium, chloride, hydrogen, etc.) within the cellular compartment of the brain. Small shifts in the extracellular potassium concentration can markedly affect acid-based homeostasis, energy metabolism, and volume regulation of these two brain cells. Since normal neuronal function is tightly coupled to the ability of the surrounding glial cells to regulate ionic shifts within the brain and since both cell types can be affected by shifts in the extracellular potassium, it is important to characterize their individual response to an elevation of this ion. This review describes the results of side-by-side studies conducted on cortical neurons and astrocytes, which assessed the effect of elevated potassium on their resting membrane potential, intracellular volume, and their intracellular concentration of potassium, sodium, and chloride. The results obtained from these studies suggest that there exists a marked cellular heterogeneity between neurons and astrocytes in their response to an elevation in the extracellular potassium concentration.
Beginning Statistics with Cuisenaire Rods

Summary Cuisenaire Rods provide a concrete embodiment for teaching mean, median, and mode to middle schoolers. These statistical concepts are traditionally only taught abstractly, but may be better understood via manipulatives.
Spacecraft Collision Avoidance Using Coulomb Forces with Separation Distance and Rate Feedback

A two-spacecraft collision avoidance problem is discussed in this paper. The spacecraft are assumed to be floating freely in deep space. A control strategy using cluster internal coulomb forces is developed to prevent a collision of the two spacecraft. The control law is designed to keep the separation distance greater than a specified constraint value, and is also designed to keep the departure relative kinetic energy at the same level with the approach kinetic energy. Further, this strategy requires only the measurements of the separation distances and the distance rates. If the achievable spacecraft charge levels are limited, then it is not guaranteed that the collision can always be prevented. Formulating the relative motion of the charged spacecraft using the concepts of orbital mechanics allows us to analyze the conditions under which a collision can be avoided. Given an initial separation distance and distance rate, the minimum spacecraft charge limit required to guarantee collision avoidance is determined. Or, inversely, when the limitations of charges are given, the maximum approach speed at which a potential collision can be avoided is estimated. Numerical simulations illustrate the analytical results.