cssi/SciSciGPT-SciSciNet huggingface dataset:
Movement Control Phases of Upper Body Coordination in Visually Guided Reach Movements

Coordination of human movement includes temporal and spatial aspects. Under the assumption that the implicit movement sequence of body segments may be associated with visual feedback information, the activation timing, time to peak velocity of the hand and sequencing of joint movements were investigated in this study. The results show that variations in movement time with target azimuth and distance fit a quadratic regression model. In addition, the time to peak velocity reveals a movement scaling property in the context of self-imposed movement speed. Finally, the sequencing of joint movement also varies with target azimuth and distance. These motor behavior properties and movement characteristics can be used to model human reach movement in a dynamic manner and to estimate task durations.
Fully multidimensional flux-corrected transport algorithms for fluids

The theory of flux-corrected transport (FCT) developed by Boris and Book [J. Comput. Phys. 11 (1973) 38; 18 (1975) 248; 20 (1976) 397] is placed in a simple, generalized format, and a new algorithm for implementing the critical flux limiting stage' in multidimensions without resort to time splitting is presented. The new flux limiting algorithm allows the use of FCT techniques in multidimensional fluid problems for which time splitting would produce unacceptable numerical results, such as those involving incompressible or nearly incompressible flow fields. The “clipping” problem associated with the original one dimensional flux limiter is also eliminated or alleviated. Test results and applications to a two dimensional fluid plasma problem are presented.
Range chart of selected lower paleozoic acritarch taxa

Abstract A range chart is presented, showing the stratigraphical distribution of more than 300 species of acanthomorphitic acritarch genera. The literature on which this chart has been based is listed (146 references, available by March, 1973).
Shedding Light on the Na+/Ca2+ Exchanger

The Na+/Ca2+ exchanger (NCX) regulates cardiac contractility by adjusting the amount of Ca2+ inside myocytes. NCX accomplishes this by using the electrochemical gradient of Na+: during each cycle three Na+ ions enter the cell and one Ca2+ ion is extruded against its gradient. In addition to being transported, cytoplasmic Na+ and Ca2+ ions also regulate exchanger activity. The physiological relevance and molecular processes underlying ionic regulation remain unclear. Also unresolved are the events that regulate NCX trafficking to the membrane and its oligomeric state. This is essential information to interpret structure-function data. The full-length exchanger was fused to both CFP and YFP, creating active fluorescent exchangers used in FRET experiments to assess both conformational changes associated with ionic regulation and the oligomeric state of NCX. Electrophysiological characterization demonstrates that these constructs behave similarly to the wild-type (WT) exchanger. We have been able for the first time to monitor conformational changes of the exchanger Ca2+-binding site in vivo. These studies provide a better understanding of the molecular properties of the NCX.
Application of a protein synthesis inhibitor into the ventral tegmental area, but not the nucleus accumbens, prevents behavioral sensitization to cocaine

Recent evidence implicates a crucial role for the ventral tegmental area (VTA) in the initiation of behavioral sensitization produced by repeated psychostimulant exposure, while changes in the nucleus accumbens (NAcc) are not critical during the initiation stage. We investigated whether the development of behavioral sensitization to repeated daily cocaine could be prevented by daily administration of the protein synthesis inhibitor, anisomycin, delivered onto VTA neurons. Rats were given five daily treatments as follows: obturators containing crystalline anisomycin or no compound (sham) were placed directly into the VTA 15 min prior to a saline (1 ml/kg, i.p.) or cocaine (15 mg/kg, i.p.) injection. After withdrawal for 8-9 days, the locomotor response to the same dose of saline or cocaine was monitored. No differences in the locomotor response to an acute saline challenge were found across the four groups. Animals given sham treatments in the VTA and daily cocaine demonstrated a significant augmentation in the locomotor response to a cocaine challenge compared to saline controls. Anisomycin treatments alone produced no effects on acute cocaine-induced locomotion. Further, a cocaine challenge in animals receiving daily anisomycin and cocaine elicited a non-augmented response similar to that of saline controls. Thus, the sensitized locomotor response to a cocaine challenge in daily cocaine pretreated animals was completely blocked by daily anisomycin treatment in the VTA. When daily anisomycin was administered into the NAcc along with daily cocaine, no blockade of behavioral sensitization was observed. These results provide support for a critical role of long-term changes in gene expression in the vicinity of VTA neurons mediating the development of sensitization to psychostimulants.
An applied technology transfer process

The applied technology transfer process is a communication process based on planning, marketing, and training. Planning is the single most important element, while pre-planning is also essential.
Culture and the nuclear-test-ban treaty

As former Webmaster for the Provisional Technical Secretariat of the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO PrepCom/PTS) in Vienna, Austria, and more recently, as implementer of an on-line scientific meetings database tool for the international organization and co-author of a paper[ ] describing why the database was created as well as how people can use it, I have been in a position to observe and can describe some of the difficulties involved in designing tools for an international/intercultural group. Most of what follows was gleaned from the paper Jerzy Knapik[ ] and I wrote as well as from work that I did supporting CTBTO both as a Sandian[ ] and as a staff member of the PTS.The Comprehensive Nuclear-Test-Ban Treaty (CTBT) was opened for signature on September 24, 1996 at United Nations Headquarters in New York. President Clinton was the first to sign it. Ratification of the Treaty has recently been the subject of heated debates in the U.S. Senate. As of October 5, 1999, the CTBT has been signed by 154 countries and ratified by 51 countries[ ]. The international organization supporting the implementation of this Treaty began operations in March of 1997 in Vienna. I was the organization's first Webmaster from November 1997 until February 1999, and have been supporting it as a Sandian both beforehand and since returning to Sandia National Laboratories (SNL) by working as Webmaster on the U.S. Department of Energy's Nuclear Explosion Monitoring Research and Engineering program's web site.The three main tasks of the international organization revolve around verifying that all countries are abiding by the terms of the Treaty. This includes development and maintenance of the International Monitoring System (IMS), which will gather data from 321 monitoring stations and 16 laboratories working in some 90 countries around the world; the International Data Centre (IDC) which will analyze data received from the IMS and make the raw data and its results available to all States parties; as well as preliminary work for conducting On-Site Inspections (OSI), which can be requested by any State party if a suspicious occurrence cannot be resolved through consultation and clarification.The Treaty calls for countries to promote cooperation among themselves (Paragraph 12 of Article IV of the Comprehensive Nuclear-Test-Ban Treaty):"The States Parties undertake to promote cooperation among themselves to facilitate and participate in the fullest possible exchange relating to technologies used in the verification of this Treaty in order to enable all States Parties to strengthen their national implementation of verification measures and to benefit from the application of such technologies for peaceful purposes."[ ]The role of the International Cooperation Section of the CTBTO PrepCom/PTS is to help countries fulfill this mission. This is not necessarily an easy task because countries have different needs, requirements and national priorities as well as different levels of economic and technological development.
Crystallization and initial crystallographic analysis of the Kelch domain from human Keap1.

The human Keap1 protein is a substrate adaptor for an E3 ubiquitin ligase complex that specifically targets the transcription factor Nrf2 for degradation. Keap1 functions as a sensor of oxidative stress, such that the inhibition of Keap1-dependent degradation of Nrf2 activates a genetic program that protects cells from reactive chemicals and maintains cellular redox homeostasis. Keap1 interacts with Nrf2 through its C-terminal Kelch-repeat domain. Kelch-repeat domains are found in a large number of proteins and are predicted to assemble into a β-propeller structure. Only a single Kelch-repeat domain, that from the fungal enzyme galactose oxidase, has had its structure determined. Here, the crystallization of the Kelch domain of human Keap1 protein by hanging-drop vapor diffusion is reported in space group P6522. Crystals diffract to 1.85 A resolution under cryocooling conditions. A selenomethionine-substituted version of the Kelch domain has also been purified and crystallizes isomorphously with the native protein. Structure determination by MAD phasing is under way. The role of Keap1 in oxidative stress and cytoprevention suggests that the Kelch domain will be an attractive target for therapeutic drug design.
Communication, Language and Health: An Overview

In this special issue, we directed our attention to the study of language and relationships within the health context in order to fill what we saw as a lacuna in the existing literature. We compare...
In situ attenuated total reflectance fourier-transform infrared study of oxytetracycline sorption on magnetite

Adsorption of antibiotics on the surfaces of common mineral sorbents plays a major role in determining their fate in soils and sediments. The mechanisms of these reactions are, therefore, important for understanding and predicting the environmental fate of antibiotics. We used in situ attenuated total reflectance Fourier-transform infrared spectroscopy to elucidate the binding mechanisms of oxytetracycline (OTC) onto the surface of magnetite [FeO], a common Fe oxide mineral in soils and sediments, as a function of pH (3-9) and aqueous OTC concentration (5-150 μmol L). Comparison of dissolved OTC spectra to those of OTC-magnetite surface complexes indicated strong interactions of OTC molecules with the FeO surface via carbonyl (C=O) and amine (-NH) moieties of the amide group (-CONH) and the N atom of the dimethyl amino group [-N(CH)]. Increasing the aqueous OTC concentration led to increased OTC adsorption but did not notably alter the OTC binding mode at the magnetite surface. The results of this study would help to assess the importance of Fe oxide minerals in determining the environmental fate of OTC in soils and sediments.
Lead, blood pressure, and cardiovascular disease in men and women.

Lead has been shown to be associated with elevated blood pressure in males in the NHANES II survey and in numerous other studies. This study confirms the association in males aged 20 to 74 and docu...
JAK1-dependent Phosphorylation of Insulin Receptor Substrate-1 (IRS-1) Is Inhibited by IRS-1 Serine Phosphorylation *

Serine phosphorylation of insulin receptor substrate-1 (IRS-1) reduces its ability to act as an insulin receptor substrate and inhibits insulin receptor signal transduction. Here, we report that serine phosphorylation of IRS-1 induced by either okadaic acid (OA) or chronic insulin stimulation prevents interferon-alpha (IFN-alpha)-dependent IRS-1 tyrosine phosphorylation and IFN-alpha-dependent IRS-1/phosphatidylinositol 3'-kinase (PI3K) association. In addition, we demonstrate that serine phosphorylation of IRS-1 renders it a poorer substrate for JAK1 (Janus kinase-1). We found that treatment of U266 cells with OA induced serine phosphorylation of IRS-1 and completely blocked IFN-alpha-dependent tyrosine phosphorylation of IRS-1 and IFN-alpha-dependent IRS-1/PI3K association. Additionally, IRS-1 from OA-treated cells could not be phosphorylated in vitro by IFN-alpha-activated JAK1. Chronic treatment of U266 cells with insulin led to a 50% reduction in IFN-alpha-dependent tyrosine phosphorylation of IRS-1 and IRS-1/PI3K association. More importantly, serine-phosphorylated IRS-1-(511-722) could not be phosphorylated in vitro by IFN-alpha-activated JAK1. Taken together, these data indicate that serine phosphorylation of IRS-1 prevents its subsequent tyrosine phosphorylation by JAK1 and suggest that IRS-1 serine phosphorylation may play a counter-regulatory role in pathways outside the insulin signaling system.
Coerulospinal fiber regeneration in transected feline spinal cord

Abstract After complete cat spinal cord transection, a collagen matrix was used to bridge the gap. Vascular supply was increased to the transection site with an omental pedicle. Before hardening, either 4-aminopyridine, laminin, glia maturation factor, or lipid angiogenic factor were mixed into the collagen. Surgically reconstructed animals were compared to transection-only controls and observed for 90 days. Fluoro-Gold was injected distal to the transection site on day 75. Immunocytochemical examination of brain and spinal cord tissue was done on day 90. Examination revealed supraspinal catecholaminergic fibers present in the collagen bridge and distal cord tissue only in cats with surgical reconstruction. Fluoro-Gold particles were found localized in locus coeruleus and other noradrenergic pontine neurons. Distal to the transection, double immunostaining with synaptophysin and tyrosine hydroxylase or dopamine-β-hydroxylase revealed dot-like deposits closely apposed to preganglionic sympathetic neurons suggestive of synaptic connectivity to these targets. Results indicate that considerable outgrowth of specific supraspinal fibers can be induced following spinal transection and reconstruction, and that such fibers may be extending and contacting appropriate distal target tissue in the cord.
A classification system for primitive neuroectodermal tumors (medulloblastoma) of the posterior fossa

Tumors of the posterior fossa are described. Although the preoperative staging system of Chang and associates has proven prognostic relevance, a proposed new system may have even greater impact on prognosis because it considers the tumor burden postoperatively. This system (MAPS: metastasis, age, pathology, and surgery) incorporates age and pathologic characteristics into the staging system. The value of this proposed staging system, in particular, the impact of pathology, must be assessed in controlled trials.
Restriction endonucleases for pulsed field mapping of bacterial genomes

Fundamental to many bacterial genome mapping strategies currently under development is the need to cleave the genome into a few large DNA fragments that can be resolved by pulsed field gel electrophoresis. Identification of endonucleases that infrequently cut a genome is of key importance in this process. We show that the tetranucleotide CTAG is extremely rare in most bacterial genomes with G+C contents above 45%. As a consequence, most of the sixteen bacterial genomes we have tested are cleaved less than once every 100,000 base pairs by one or more endonucleases that have CTAG in their recognition sequences: Xba I (TCTAGA), Spe I (ACTAGT), Avr II (CCTAGG) and Nhe I (GCTAGC). Similarly, CCG and CGG are the rarest trinucleotides in many genomes with G+C content of less than 45%. Thus, Sma I (CCCGGG), Rsr II (CGGWCCG), Nae I (GCCGGC) and Sac II (CCGCGG) are often suitable endonucleases for producing fragments that average over 100,000 base pairs from such genomes. Pulsed field gel electrophoresis of the fragments that result from cleavage with endonucleases that cleave only a few times per genome should assist in the physical mapping of many prokaryotic genomes.
An evolutionary approach for achieving scalability with general regression neural networks

In this paper, we present an approach to overcome the scalability issues associated with instance-based learners. Our system uses evolutionary computational techniques to determine the minimal set of training instances needed to achieve good classification accuracy with an instance-based learner. In this way, instance-based learners need not store all the training data available but instead store only those instances that are required for the desired accuracy. Additionally, we explore the utility of evolving the optimal feature set used by the learner for a given problem. In this way, we attempt to deal with the so-called "curse of dimensionality" associated with computational learning systems. To these ends, we introduce the Evolutionary General Regression Neural Network. This design uses an estimation of distribution algorithm to generate both the optimal training set as well as the optimal feature set for a general regression neural network. We compare its performance against a standard general regression neural network and an optimized support vector machine across four benchmark classification problems.
Chondroblastoma of the scapula. A case report with ultrastructural observations.

A large chondroblastoma of the scapula, with articular and soft-tissue extension, the fourth recorded in this location, was removed by forequarter amputation in a 29-year-old man after 12 years of growth. Ultrastructurally, die typical chondroblastoma cells was characterized by indented, multilobular nuclei with narrow peripheral bands of electron-dense substance, by a subdivision of the cytoplasm into an electron-dense endoplasm containing most of the organelles and an electron-lucent ectoplasm largely devoid of structured components, by fine intracytoplasmic fibrils frequently forming dense band-like aggregates between endo-and ectoplasm, and by numerous blunt microvilli at the cell surface. Also present were fusiform cells of uncertain nature and multinudeated giant cells of foreign body or osteoclastic type. The interstitium contained collagen and thin reticular fibrils; the latter appeared to be a product of the tumor cells. The observed ulaastructural features support the view that chondroblastoma is a tumor derived from cartilage-forming matrix cells.
When do leaders matter? Ownership, governance and the influence of CEOs on firm performance

Abstract Leadership and strategic management research suggests that the extent to which CEOs influence performance largely depends on the presence or absence of certain factors. These factors may include the characteristics of the task at hand, subordinates, the organization itself or the external environment. Among these factors, a fundamental contingency that has received little empirical attention is an organization's ownership and governance structure —that is, who owns and monitors the organization. In this paper, we outline how different ownership and governance structures can present the opportunity for, or limit, leader influence and empirically examine the extent to which CEO effects on financial performance depend on these structures. Examining organizations in the same industry but with different ownership and governance structures, our results suggest that these structures are closely aligned with the degree to which CEOs influence firm performance. Our findings support the notion that leaders matter most when ownership and governance structures correspond with a weak or ambiguous institutional logic. This study contributes new insight into the “opportunity structure” of CEO influence, that is, the organizational factors that shape leader discretion and, hence, condition the CEO's level of influence over firm performance.
Determination of a Biological Absorber Depth Utilizing Multiple Source−Detector Separations and Multiple Frequency Values of Near‐Infrared Time‐Resolved Spectroscopy

Visualization of the photon path in scattering media is attempted through the use of frequency response analysis of near-infrared time-resolved spectroscopy (NIR-TRS) spectra. The effect of the source-detector distances and the modulation frequency on the photon path is examined. It was found that the use of multifrequency information could lead to the possibility of obtaining the information of an absorber's depth without increasing the number of measurements.
Presynaptic α-2 receptors inhibit norepinephrine release in tracheal smooth muscle

Abstract The presence of inhibitory presynaptic α-2 adrenergic receptors and their ability to modulate nerve-mediated relaxation responses was examined in strips of canine tracheal smooth muscle (TSM). TSM strips were incubated with 3 H-labelled norepinephrine (NE), rinsed, and mounted in superfusion chambers for electrical stimulation (ES) of the intramural adrenergic neurons. Yohimbine, an α-2 receptor antagonist, increased the release of [ 3 H]NE into the superfusate during ES and decreased the amount of [ 3 H]NE remaining in TSM strips after ES, indicating the presence of presynaptic α-2 receptors. Whether these α-2 receptors were functional in atropine-treated TSM was determined by comparing the inhibitory effect of ES on TSM contractions induced by histamine in the absence and presence of yohimbine. Relaxation of TSM strips at stimulus frequencies of 1–20 Hz was significantly greater in the presence of yohimbine. Moreover, the stimulus frequency required to produce a 50% relaxation, was 5.1±0.9 Hz in control strips, but only 2.1±0.4 in TSM strips pretreated with yohimbine. We conclude that presynaptic α-2 receptors serve a functional role in regulating NE release in canine TSM.
Heme inhibits cartilage metabolism and growth in vitro

Abstract The present study was designed to investigate the potential role of heme as a direct inhibitor of cartilage metabolism and growth. We used the embryonic chick pelvic rudiment bioassays and the hypophysectomized rat cartilage sulfation bioassay, both sensitive to growth factors and growth inhibitors. In the chick bioassay pelvic rudiment growth was inhibited when heme was added to the culture medium at 0.1 mmol/L (after five days in culture, cartilage weight 224% ± 11% of initial with normal serum, but 141% ± 3% of initial with serum plus heme 0.25 mmol/L); the heme-induced growth inhibition was promptly reversible when cartilages were placed in heme-free medium. This was due, at least in part, to heme-induced inhibition of (1) [ 35 S] sulfate incorporation into proteoglycans by as little as 0.05 mmol/L heme (66% ± 5% of assay buffer); (2) [ 14 C] leucine incorporation into proteins by ≥0.05 mmol/L heme (85% ± 6% of assay buffer); and (3) [ 3 H] uridine incorporation by ≥0.10 mmol/L heme (50% ± 4% of assay buffer). In the rat cartilage sulfation bioassay (the literature “standard” bioassay for skeletal growth studies) a dose-dependent inhibition of [ 35 S] sulfate incorporation occurred with ≥0.01 mmol/L added heme (82% ± 3% of assay buffer). Heme caused a dose-dependent and reversible inhibition of cartilage metabolism and growth, and it may have a novel role in the pathophysiology of growth retardation associated with some chronic disease.
Brain interneurons in noctuoid moths: binaural excitation and slow potentials.

Abstract A method is described for measuring small differences in the acoustic sensitivity of protocerebral interneurons on one side of the noctuid brain when ultrasonic pulses are directed first at one tympanic organ and then at the other. In 23 preparations ipsilateral sensitivity of the brain interneurons was consistently greater by 3 to 4 dB (range 0–7 dB). The spike response of protocerebral interneurons to tympanic stimulation was accompanied by a negative potential having a time course of 40 to 50 msec in response to a 10 msec stimulus pulse. The consistent positive ipsilateral bias in the sensitivity of brain interneurons is much less than the increased sensitivity of the tympanic organ when sounds originate on the ipsilateral side as compared with its sensitivity to sounds directed at the contralateral side. A possible neural mechanism and the behavioural significance of this arrangement are discussed.
Geochemical and isotopic constraints on the diagenetic history of a massive stratal, late Cambrian (Royer) dolomite, Lower Arbuckle Group, Slick Hills, SW Oklahoma, USA

Abstract The diagenetic history of the late Cambrian massive Royer dolomite from the lower Arbuckle Group, Slick Hills, SW Oklahoma, USA, has been evaluated through comprehensive geochemical analyses. The dolomite probably formed during early diagenesis from contemporaneous late Cambrian seawater, evidenced by similar 87 Sr 86 Sr ratios (from 0.70891 to 0.70913) of most (70%) dolomite samples, to coeval late Cambrian seawater (from 0.7089 to 0.7092). Very light δ18O values (−10.2 to −12.9‰, PDB), however, indicate that the dolomite was significantly modified during burial. Correlation of various geochemical parameters (Sr, Fe, δ18O, and 87 Sr 86 Sr ) demonstrates that dolomite samples with increased modification are characterized by lower Sr and higher Fe concentrations, lighter δ18O values, and less radiogenic 87 Sr 86 Sr ratios. This correlation, coupled with the light δ18O values of the dolomite, demonstrates that meteoric water, recharged into overlying carbonates, was responsible for burial modification of the dolomite. Geochemical comparison of the dolomite with associated limestone and quantitative modelling of δ18O, Sr, and 87 Sr 86 Sr variation during water-rock interaction suggest that the dolomite underwent long-lasting modification. The timing of meteoric modification was coincident with the development of regional overlying unconformities corresponding to emergence of the carbonate platform. Similar diagenetic modification has probably been responsible for 18O depletion and trace element modification of ancient dolomites in many other areas, although many of these dolomites have been interpreted to have formed either in mixing-zone environments or in subsurface environments.
High School Teachers and African American Parents: A (Not So) Collaborative Effort to Increase Student Success

This is a case study about a group of African American parents that banded together in an effort to increase their own involvement, the involvement of other African American parents, and the success of African American students at one public high school. The various ways in which this group of parents sought to accomplish their goals, however, was not entirely embraced by school faculty. Consequently, their efforts were undermined and unutilized. The findings suggest that schools require parents, even when unified and with a common purpose, to comply with a specific protocol for involvement or risk being marginalized. It is argued that parent involvement is often based on support and compliance. Parents, moreover, are frequently regarded as one homogenous group, which ignores the varied experiences, visions, and values of ethnic minority parents.
Browning's Career to 1841: The Theme of Time and the Problem of Form

In the “Ode on a Grecian Urn,” Keats describes how, in the moment of contemplation, the poet is conscious of his limitations as an earthbound creature, one of a generation which “old age shall … waste,” one who has felt the moment of “human passion … / That leaves a heart high-sorrowful and cloy'd, / A burning forehead, and a parching tongue.” By contrast, the urn suggests the power of art to prolong the moment, to render permanent what is transitory, to recreate endlessly for one generation after the next the passion of human love. But the urn itself may not last forever; it is a “sylvan historian” which is itself the product of the “slow time” of human history, an artifact which commemorates a moment in the life of its creator and emulates eternity without itself being eternal (“Thou, silent form, dost tease us out of thought / As doth eternity …”). It is a “still unravish'd bride of quietness,” but if we dwell on the ambiguous “still,” we sense that like the Elgin marbles, the urn may be subject to “the rude / Wasting of old Time,” a hint at the “magnitude of eternity” which impresses on the poet a sense of his mortality.
Retention in reversed-phase liquid chromatography: solvatochromic investigation of homologous alcohol-water binary mobile phases

Abstract The mechanism of retention in reversed-phase liquid chromatography (RPLC) has been further investigated using the ET(30) solvatochromic solvent polarity scale. The retention behavior of a variety of solutes was measured using a homologous series of normal alcohols as the organic modifiers in hydroorganic mobile phases. The results imply that a systematic change in the extent of solvation of the stationary phase occurs with respect to the size of the organic modifier. It was also found that a linear extrapolation of the log k′ versusET(30) plots for different mobile phases using methanol, ethanol and acetonitrile (but not n-propanol) as modifiers, intersected at approximately the ET(30) value of pure water. This intersection is further evidence that the ET(30) model of solute retention is a useful tool with which to study the mechanism of retention in RPLC. The extrapolated retention value in water, log k′w, from the ET(30) plots should then prove to be a more reliable means of estimating solute lipophilicity using RPLC than the percent organic modifier model.
A contemporary survey of covalent connectivity and complexity. The divergent synthesis of poly(thioether) dendrimers. Amplified, genealogically directed synthesis leading to the de gennes dense packed state

A new poly(thioether) dendrimer (d-PTE) family is synthesized using preformed branch cell reagents (BCR) in a “genealogically directed syntheses” (GDS) strategy. Bicyclic orthoester functionality is introduced into a branch cell reagent (BCR) to temporarily mask pentaerythritol derived branch cells which are used to construct the interior of this new dendrimer family. These BCRs with multiplicities =3 (Nb=3), are organized and amplified around an initiator core with multiplicity = 4 (Nc=4). The initiator core, pentaerythritol tetrabromide (Nc=4), is allowed to react with four equivalents of 4-acetothiomethyl-2,6,7-trioxabicyclo[2.2.2]octane (Nb=3) in the presence of base, to form the first generation possessing four bicyclic orthoester groups. After deprotection and transformation to bromide surface groups via tosylate intermediates, the second generation possessing twelve bicyclic orthoester groups is formed. Surprisingly, attempted displacement of all 36 surface groups at the third generation level showed that only one third of the end groups could be substituted. These experimental data suggest that this (Nc=4, Nb=3) type dendrimer family exhibits de Gennes dense packing properties at the third generation level. Elemental analysis, FTIR, H/C13 nmr spectroscopy and mass spectroscopy were used to confirm the structures. Molecular simulation data suggest that this dendrimer family should not undergo de Gennes dense-packing until the fourth generation. Steric requirements of the bulky mercaptomethyl anion used in the SN2 displacement of terminal bromides on this congested surface are proposed as the reason for incomplete formation of the third generation. This observation illustrates another example of “sterically induced stoichiometry” (SIS).
A Tracking System of Multiple LiDAR Sensors Using Scan Point Matching

We address a tracking system of 360° field of view using Light Detection And Ranging (LiDAR) sensors, which are a key module for detecting surrounding traffic and infrastructure for vehicular safety applications. We propose a joint algorithm for estimating motion and a nonparametric contour model whose complexity is O(N), with N being the number of scan points. Particularly, the proposed nonparametric model has the potential to track objects with arbitrary shape (e.g., car, pedestrian, and bicycle). A comparison of the proposed approach with other methods using parametric models shows the robustness and the quality of the proposed system. Quantitative performance evaluation against ground truth is presented in tracking a car, a pedestrian, and a bicycle. Experiments demonstrate that the proposed system substantially improves performance. Road test results show the effectiveness and efficiency of the implemented system. A lane-change alert (LCA) demonstration system is built based on the detection system, and the LCA performance is analyzed using ground truth.
Relationships among nutrient enrichment, detritus quality and quantity, and large-bodied shredding insect community structure

Anthropogenic nutrient enrichment of forested headwater streams can enhance detrital quality, decrease standing stocks, and alter the community structure of detrivorous insects, reducing nutrient retention and decreasing ecosystem functioning. Our objective was to determine if stoichiometric principles could be used to predict genus-specific shifts in shredding insect abundance and biomass across a dissolved nutrient and detritus food quality/quantity gradient. Detritus, insect, and water samples were collected from 12 Ozark Highland headwater streams. Significant correlations were found between stream nutrients and detrital quality but not quantity. Abundance and biomass responses of four out of five tested genera were accurately predicted by consumer-resource stoichiometric theory. Low carbon:phosphorus (C:P) shredders responded positively to increased total phosphorus and/or food quality, and high C:P shredders exhibited neutral or negative responses to these variables. Genus-specific declines were correlated with decreased overall biomass in shredder assemblages, potentially causing disruptions in nutrient flows to higher level consumers with nutrient enrichment. This work provides further evidence that elevated nutrients may negatively impact shredding insect communities by altering the stoichiometry of detritus–detritivore interactions. A better understanding of stoichiometric mechanisms altering macroinvertebrate populations is needed to help inform water quality criteria for the management of headwater streams.
Nonlinear parameter estimation applied to a model of smooth pursuit eye movements

We present a procedure that optimally adjusts specified parameters of a mathematical model to describe a set of measured data. The technique integrates a dynamic systems-simulation language with a robust algorithm for nonlinear parameter estimation, and it can be implemented on a microcomputer. Sensitivity functions are generated that indicate how the operation of the model is affected by each updated parameter. This procedure offers a greater resolution of optimal parameter values than other, less rigorous methods. To illustrate this technique we have applied it to the model of human smooth pursuit eye movements proposed by D.A. Robinson and colleagues (1986).
An Optimal Procedure for Allocating Manpower with Cyclic Requirements

Abstract Certain types of organizations operate continuously and must allocate personnel over time to meet fluctuating, but cyclical, staff requirements. The optimal allocation of personnel in this situation is formulated as an integer linear programming problem, and the special structure of the formulation is exploited in order to develop an efficient solution algorithm which requires only hand calculations. The relationship between optimal solutions and flexibility in the original data is also considered.
Semi-Markov performance model of CSMA/CD networks

Abstract A semi-Markov model of a Carrier Sensing Multiple Access with Collision Detection network was developed by including the transition probabilities and state holding times (sojoum times) 1 in the Markovian Chain. Using the flexibility of the semi-Markov approach, realistic and practical values of propagation, transmission detection, collision, packet transmission and re-transmission delays were utilized. Performance measures, including throughput, delay, mean time between collisions and mean time between safe transmissions, are evaluated for the Semi-Markov Process and embedded Markovian Chain. Three sets of throughput and delay characteristics were obtained for the three, 16 and 50 retries limit by using a recursive algorithm to solve the chain. The analytical results are compared with the simulation results obtained by using the discrete event simulation technique.
Copper(II) Complexes of 2-Butyl-, 2-Isobutyl-, 2-Sec-Butyl, and 2-Tert-Butylaminopyridine N-Oxides

Abstract Copper(II) complexes of 2-butyl-, 2-isobutyl-, 2-sec-butyl- and 2-tert-butylaminopyridine N-oxide (BH, IBH, SBH and TBH, respectively) have been prepared from the following salts: tetrafluoroborate, nitrate, chloride, bromide and acetate. Solids of the general formula [Cu(LH)4](X2) (where LH[dbnd]all four ligands when X[dbnd]BF4 − and LH[dbnd]BH and SBH when X[dbnd]NO3 −) and [Cu(LH)2X2] (where LH[dbnd]IBH and TBH when X[dbnd]NO3 −). The complexes prepared with the two halide salts are polymeric and have empirical formulas of either Cu(LH)2X2 or Cu(LH)X2 or a combination of the two. With copper(II) acetate complexes of stoichiometry [CuL2] (where is L[dbnd]conjugate base of BH, IBH and SBH) were isolated and all of the complexes were characterized using spectral methods (i.e., IR, UV-Vis and ESR). All four ligands coordinate solely via the N-oxide oxygen except for their conjugate bases which also coordinate via the amine nitrogen to act as bidentate ligands. Substantial stereochemical and stoich...
Nurse staffing and health care-associated infections: Proceedings from a working group meeting

The nation is facing a nursing shortage that is creating a crisis for quality health care and patient safety. Research has documented that problems with nurse staffing are associated with health care-associated infections and other adverse events that affect patient outcomes. These ominous facts, stated during the opening of an expert consultants meeting convened by the Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, laid the foundation for a day-long discussion and a call to action to address a growing crisis in health care. The authors summarize the proceedings of this meeting and present the consultants' suggestions for drawing national attention to this issue.
An Extracellular Domain of BK Channel β1 Accessory Subunit Modulates the Activities of Voltage Sensor and Gate

A family of tissue-specific auxiliary β subunits modulate large conductance, voltage- and calcium- activated potassium (BK) channel gating properties to suit their diverse function. Paradoxically, β subunits both promote BK channel activation through a stabilization of voltage-sensor activation, and reduce BK channel openings through an increased energetic barrier of the closed-to-open transition. The molecular determinants underlying β-subunit function, including the dual gating effects remain unknown. Here, we report the first identification of a β1 functional domain consisting of Y74, S104, Y105 and I106 residues located in the extracellular loop of β1. These amino acids reside within two regions of highest conservation among related β1, β2 and β4 subunits. Analysis in the context of the Horrigan-Aldrich gating model revealed that this domain functions to both promote voltage-sensor activation, but also reduce intrinsic gating. Free energy calculations suggest that the dual effects of the β1 Y74, S104-I106 domain can be largely accounted for by a relative destabilization of channels in open states that have few voltage sensors activated. These results suggest a unique and novel mechanism for β subunit modulation of voltage-gated potassium channels wherein interactions between extracellular β subunit residues with the external portions of the gate and voltage sensor regulate channel opening.
Effect of threading edge dislocations on the photoluminescence spectra for n-type wurtzite GaN

A computational approach to study the effect of threading edge dislocation density on photoluminescence in $n$-type wurtzite GaN is presented and the calculated results are compared with experimental data. A calculation domain with a dipole of edge dislocations in three-dimensional real space is analyzed and its size is varied to study the effect of dislocation density. A $6\ifmmode\times\else\texttimes\fi{}6$ $\mathbf{k}∙\mathbf{p}$ Hamiltonian is solved to determine the energy levels and wave functions for valence electrons using the finite element method; the conduction band is calculated separately by taking advantage of the wide band gap of $3.44\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$. The spontaneous emission spectrum is then evaluated. The electrostatic potential of the edge dislocation, due to its electron-acceptor nature, and the deformation potential associated with the strain field of the edge dislocation reduce the intensity and broaden the peak of the band edge emission. Besides the band edge peak, three distinct peaks are observed below the band edge transition energy. These peaks are from transitions to dislocation-localized hole states with energies within the band gap created by the electrostatic potential of the edge dislocations. Compared to the effect of the electrostatic potential, the strain field effect is negligible in generating emission peaks below the band edge transition energy, but it is still significant enough to contribute to broadening the band edge peak. The calculated band edge peak intensities closely agree with experimentally measured band edge photoluminescence intensities. The calculated and experimental data both show a significant reduction of band edge peak intensity for a dislocation density higher than ${10}^{7}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}$ as the dislocation density increases. The intensity of band edge peaks reduces significantly with high dislocation densities and low carrier concentrations, which indicates that GaN becomes dislocation sensitive like other III-V materials if insufficient carriers are present.
Energy quantization for triholomorphic maps

Let \(\{u_n\}\subset H^1(M, N)\) be weakly convergent stationary triholomorphic maps from a hyperkahler manifold M to another hyperkahler manifold N. We establish an energy quantization for the density function of the defect measure on the concentration set.
The smooth cohomology of $N=2$ supersymmetric Landau-Ginzburg field theories

We compute the smooth cohomology (both unrestricted and compactly supported) of the supercharge of an ultraviolet cutoffN=2 supersymmetric Landau-Ginzburg field theory.
"Make Hell While the Sun Shines": Proverbial Rhetoric in Winston Churchill's The Second World War

(1995). “Make Hell While the Sun Shines”: Proverbial Rhetoric in Winston Churchill's The Second World War. Folklore: Vol. 106, No. 1-2, pp. 57-69.
220 GHz ultra wide band TWTA: Nano CNC fabrication and RF testing

Precision fabrication and RF testing of a 220 GHz GHz sheet beam TWTA based on the double vane half-period staggered slow wave structure design[1]is reported. NanoCNC Milling technology[2] was employed to precision fabricate the entire TWTA circuit in bulk copper, incorporating input and output couplers, sever ports, and the slow wave structure with matching. To accommodate an overhead input/output coupler design, the TWTA circuit was fabricated in a three layer process with dimensional tolerance of within ~1-2 μm and surface roughness ~50 nm. The TWTA circuit was diffusion bonded (at UC Davis) within an accuracy of less than 10 μm between two circuit halves. Initial TWTA cold tests employing a BWO based scalar network analyzer showed an in-band insert ion loss of ~ -5 dB with a bandwidth exceeding 50 GHz. The in-band return loss was <; -12 dB. These measurements were subsequently confirmed using an Agilent PNA-X VNA. The hot test setup is ready to test the TWTA being baked at CPI and the latest test results will be presented at the conference and added to the abstract.
High-dose bone morphogenetic protein–induced ectopic abdomen bone growth

Abstract Background context Infuse [bone morphogenetic protein (BMP)] is increasingly used in spinal fusion surgery. Purpose The authors report a rare complication of BMP use. Study design This is a case report. Patient sample A 55-year-old male underwent a thoracic T8 to the pelvis fusion for degenerative lumbar disc disease and pseudarthrosis at another institution. The procedure involved an anterior and posterior approach with the use of multiple units of BMP. Methods The patient presented to our institution with complaints of weight loss, pain, tenderness, and increasing solid growth in the left lower quadrant several months after his surgery. A computed tomography revealed ectopic bone growth in the retroperitoneal area and pelvis contiguous to the anterior lumbar exposure. Results The anterior wound was reexplored, and a large sheet of ectopic bone was removed from the retroperitoneal space. Conclusions We report a rare case of extraspinal ectopic bone growth because of the use of multiple packages of BMP.
Solvent-accessible Residues on the Metal Ion-dependent Adhesion Site Face of Integrin CR3 Mediate Its Binding to the Neutrophil Inhibitory Factor

Neutrophil adhesion-dependent functions such as chemotaxis, spreading, and phagocytosis are inhibited by neutrophil inhibitory factor (NIF), a glycoprotein produced by the hookworm Ancylostoma caninum. The NIF binding site has been localized to the A-domain of integrin CR3 (CD11b/CD18) and shown to be metal-dependent. The recently solved crystal structure of the A-domain from CD11b revealed a putative metal ion-dependent adhesion site (MIDAS) on the top of the structure. To determine if NIF binds to the A-domain at its MIDAS face, amino acid substitutions involving 24 residues present in surface loops and adjacent helices in the structure were created. The expressed CD11b A-domain and CR3 heterodimers were then tested in a blinded manner for their ability to bind to biotinylated NIF. The solvent-exposed Gly143, Asp149, Glu178-Glu179, and Arg208, all located on the MIDAS face, in close proximity to the metal ion, were involved in CR3-NIF interaction. These data show that the natural integrin antagonist, NIF, binds to CR3 through the MIDAS region and identify putative contact residues in this region that could be targeted therapeutically.
Advanced laser driver for soft x-ray projection lithography

A diode-pumped Nd:YAG laser for use as a driver for a soft x-ray projection lithography system is described. The laser will output 0.5 to 1 J per pulse with about 5 ns pulse width at up to 1.5 kHz repetition frequency. The design employs microchannel-cooled diode laser arrays for optical pumping, zigzag slab energy storage, and a single frequency oscillator injected regenerative amplifier cavity using phase conjugator beam correction for near diffraction limited beam quality. The design and initial results of this laser's activation experiments are presented.
Experiences using a collaborative electronic textbook: bringing the "guide on the side" home with you

Much has been made of the transition of the instructor's role from "Sage on the Stage" to "Guide on the Side", focusing on active and collaborative learning in the classroom. The process of acquiring knowledge from textbooks has largely remained unaffected by this transition. Our work on electronic textbooks (e-textbooks) has focused on building e-textbooks that extend the reach of collaborative and active learning techniques to the reading process. This paper describes the outcomes of using our e-textbook in a one semester course on programming language design and implementation, including the impact on student learning, the degree to which they took advantage of the e-textbook's collaborative and active features, and their reaction to the use of the e-textbook as the primary text resource.