cssi/SciSciGPT-SciSciNet huggingface dataset:
Do false positive thallium-201 scans lead to unnecessary catheterization? outcome of patients with perfusion defects on quantitative planar thallium-201 scintigraphy

Objectives. We postulated that artifactually abnormal thallium-201 scans are well identified at the time of initial clinical interpretation by experienced readers and do not lead to unnecessary coronary angiography. Background. Exercise thallium-201 scintigraphy employing quantitative imaging techniques has yielded sensitivity and specificity values of 80% to 90%. There are image artifacts, such as breast shadows, and variants of normal that, if not correctly identified, can lead to a high false positive rate for detection of coronary artery disease. Methods. Data from 338 consecutive patients with one or more focal thallium-201 defects on quantitative planar Images were reviewed. All patients had undergone symptom-limited exercise scintigraphy and were classified as having either artifactual or nonartifactual thallium-201 defects after review of clinical reports. Results. Of the 265 patients with defects judged to be nonartifactual on clinical readings, 167 underwent coronary angiography, which demonstrated significant coronary artery disease (≥50% stenosis) in 161 (96%) and normal findings in 6. Four of the latter six had documented prior myocardial infarction. The remaining 73 patients (85% female) had thallium-201 defects deemed to be artifactual on clinical readings, chiefly as a result of breast (66%) and diaphragmatic (8%) attenuation or variants of normal (26%). Only 4 (5%) of the 73 patients underwent subsequent coronary angiography; none had coronary artery disease. One had aortic stenosis and two had variant angina. Follow-up (mean 20 ± 2 months) of the 69 patients in this group who did not undergo coronary angiography revealed no deaths and one nonfatal non-Q wave myocardial infarction. Conclusions. Artifactual defects on quantitative planar thallium-201 scintigraphy are well recognized by experienced interpreters and do not result in a high false positive rate leading to unnecessary cardiac catheferization. The incidence of coronary artery disease is high in patients with thallium-201 defects judged to be nonartifactual, and many patients with perfusion defects and angiographically normal coronary arteries have organic heart disease.
Visual attention in mixed-gender groups

A basic principle of objectification theory is that a mere glance from a stranger represents the potential to be sexualized, triggering women to take on the perspective of others and become vigilant to their appearance. However, research has yet to document gendered gaze patterns in social groups. The present study examined visual attention in groups of varying gender composition to understand how gender and minority status influence gaze behavior. One hundred undergraduates enrolled in psychology courses were photographed, and an additional 76 participants viewed groupings of these photographs while their point of gaze was recorded using a remote eye-tracking device. Participants were not told that their gaze was being recorded. Women were viewed more frequently and for longer periods of time than men in mixed-gender groups. Women were also more likely to be looked at first and last by observers. Men spent more time attending to pictures of women when fewer women were in the group. The opposite effect was found for pictures of men, such that male pictures were viewed less when fewer pictures of men were in the group. Female observers spent more time looking at men compared to male observers, and male observers spent more time looking at women than female observers, though both female and male observers looked at women more than men overall. Consistent with objectification theory, women’s appearance garners more attention and interest in mixed-gender social groups.
Impact of standardization sample design on Tikhonov regularization variants for spectroscopic calibration maintenance and transfer

Multivariate spectroscopic calibration models are only valid to predict samples within the span of the calibration sample space measured relative to the current instrument environment (the primary conditions). Predicting samples in secondary conditions with new variances, same sample variances as the calibration space but a new instrument environment, or both, requires some form of continual model maintenance and/or transfer. Previous work has shown that a Tikhonov regularization (TR) approach is capable of accomplishing both tasks by updating the primary model based on only a few samples (transfer or standardization set) measured under the secondary conditions. A distinction of the TR design for calibration maintenance and transfer is a defined weighting scheme for the small set of standardization samples augmented to the full set of primary calibration samples. Critical to successful calibration maintenance or transfer is the standardization sample set composition, i.e. standardization samples should properly represent that are less secondary conditions. This paper reports on using TR-based methods to investigate this issue and a consensus modeling approach is briefly evaluated. Copyright © 2010 John Wiley & Sons, Ltd.
Calculatingp(n) Modulo Small Primes Using Quadratic Forms

Abstract We use a telescoping method suggested by Ono [5] to compute p ( n ) (mod l) as a weighted sum over l-affine partitions of size n . When l=2, 3, 5, 7, and 11, these sums are neatly described using binary quadratic forms. Moreover, one immediately obtains classical proofs of the Ramanujan congruences (mod 5), 7, and 11.
Reaction processes effecting the analysis of chloroform by direct aqueous injection gas chromatography

Abstract Several important reaction processes which influence the analysis of chloroform by direct aqueous injection (DAI) gas chromatography have been identified through an investigation of the chlorination reactions of humic acid and a series of simple polyhydroxyaromatic and diketone model compounds in dilute solution. The reaction of chlorine with each substrate system was studied over the pH range 2–12. Gas chromatographic analysis by the DAI and organic solvent liquid-liquid extraction (LLE) procedures gave different measurements for the yield of CHCl 3 depending on the pH of the reaction solution and the chemical structure of the substrate. Under acidic and neutral conditions, a variety of trichloromethyl-substituted intermediates were identified at high concentrations in addition to chloroform by GC/MS. Chloral hydrate, trichloroacetic acid, pentachloroacetone and hexachloroacetone undergo hydrolysis and/or decarboxylation to form CHCl 3 at the high injection port temperatures employed in aqueous injection GC analysis. The results obtained in the current study indicate that the decomposition of these and structurally-related species accounts for differences previously observed upon application of the DAI and either the LLE or purge-and-trap techniques for the determination of CHCl 3 in chlorinated natural waters.
Segmentation of diffuse reflectance hyperspectral datasets with noise for detection of Melanoma

We present a segmentation algorithm that allows optical properties to be extracted from diffuse reflectance hyperspectral datasets with a speedup of three orders of magnitude when compared to current methods. Such data could be used for the detection of melanoma. The algorithm first performs dimensionality reduction using principal component analysis, and then the image is segmented using k-means clustering. The mean spectrum from each cluster is then calculated and can be used to extract chemical information. By reducing the number of spectra to be analyzed, extraction of physiological information can be achieved three orders of magnitude faster than methods requiring the analysis of every spectrum in the hyperspectral dataset. The effect of noise on the ability of the algorithm to accurately segment images was tested using digital phantoms, for which the noise level was under the control of the investigators. The analysis showed a linear relationship between the level of noise and the smallest difference in scattering that the algorithm was able to accurately detect and segment. This finding can be used to determine the maximum amount of noise in the imaging system that will still allow detection of the difference in optical properties between non-melanoma and melanoma.
Thermodynamic Effects of the Hydrophobic Surfactant Proteins on the Early Adsorption of Pulmonary Surfactant

Abstract We determined the influence of the two hydrophobic proteins, SP-B and SP-C, on the thermodynamic barriers that limit adsorption of pulmonary surfactant to the air–water interface. We compared the temperature and concentration dependence of adsorption, measured by monitoring surface tension, between calf lung surfactant extract (CLSE) and the complete set of neutral and phospholipids (N&PL) without the proteins. Three stages generally characterized the various adsorption isotherms: an initial delay during which surface tension remained constant, a fall in surface tension at decreasing rates, and, for experiments that reached ∼40 mN/m, a late acceleration of the fall in surface tension to ∼25 mN/m. For the initial change in surface tension, the surfactant proteins accelerated adsorption for CLSE relative to N&PL by more than ten-fold, reducing the Gibbs free energy of transition (ΔG 0 ‡ ) from 119 to 112 kJ/mole. For the lipids alone in N&PL, the enthalpy of transition (ΔH 0 ‡ , 54 kJ/mole) and entropy (− T · ΔS 0 ‡ , 65 kJ/mole at 37°C) made roughly equal contributions to ΔG 0 ‡ . The proteins in CLSE had little effect on − T · ΔS 0 ‡ (68 kJ/mole), but lowered ΔG 0 ‡ for CLSE by reducing ΔH 0 ‡ (44 kJ/mole). Models of the detailed mechanisms by which the proteins facilitate adsorption must meet these thermodynamic constraints.
Knowledge and Orientations of Internal Medicine Trainees Toward Periodontal Disease

Background: There is growing evidence that periodontal disease may be a source of systemic inflammation that impacts overall health. As such, periodontal disease is associated with an increased risk of systemic illnesses such as cardiovascular disease and adverse outcomes in diabetes mellitus and pregnancy. With the aim of assessing oral health knowledge and orientations of physicians in training, we surveyed incoming internal medicine trainees about their general knowledge, attitudes, and behaviors/practices about periodontal health and disease.Methods: A 16-question survey was distributed during orientation to incoming internal medicine trainees at a single urban teaching hospital in New York City in 2007 and 2008. Questions aimed to assess the knowledge levels of the subjects about periodontal disease and their attitudes toward discussing/evaluating the periodontal status of their patients. The study was approved by the Montefiore Institutional Review Board.Results: Of 125 incoming medical trainees que...
Stability of imperfect columns with nonlinear connections under eccentric axial loads including shear effects

Abstract An analytical method that evaluates the lateral stability and induced bending moments, shears, and second-order deflections in columns with initial geometric imperfections (i.e., initial curvature, out-of-plumb, and axial load eccentricities) and nonlinear semirigid connections subjected to axial load at both ends and lateral load at the top end is presented including the effects of shear forces and corresponding strains using three different approaches. The first two approaches are those by Haringx and Engesser that include the shear component of the applied axial force proportional to the angle of rotation of the cross section and to the total slope the along the member, respectively. The third approach is a simplified formulation based on the classical Euler theory that includes the effects of shear deformations but neglects the shear component of the applied axial force along the member. The proposed equations can be applied to columns with sidesway uninhibited, partially-inhibited and totally-inhibited. The proposed model is limited to prismatic columns subjected to eccentric axial loads at both ends and a lateral load at the top end causing bending about one of the principal axes with inelastic behavior taking place at the end rotational connections only. Five classical column cases and sensitivity studies are presented and discussed in detail. Analytical results indicate that the stability and second-order response of a column are highly affected by its initial imperfections, low shear stiffness relative to the bending stiffness, the stiffness of the lateral bracing, and by any changes in the stiffness and strength of the end connections.
Probing Membrane Protein Sequestration and Oligomerization in Polymer-Tethered Phospholipid Bilayers Containing Raft-Mimicking Lipid Mixtures

Lipid heterogeneities in plasma membranes are increasingly recognized to influence membrane protein distribution and function. Previous advancements in the understanding of such lipid-mediated protein sequestration processes have been rather sluggish, due to the small size and transient nature of lipid heterogeneities in cellular membranes. Therefore, theoretical approaches and model membrane studies have become important research tools. Recently, we introduced a powerful model membrane platform that allows the parallel analysis of membrane protein sequestering and oligomerization in well-defined lipid environments using confocal fluorescence intensity analysis paired with the photon counting histogram method. A hallmark of this single molecule-sensitive experimental strategy is the ability to monitor membrane proteins in micron-size membrane domains in the absence of artificial crosslinking agents. Specifically, we could show that native ligands, bilayer asymmetry, and cholesterol content have a profound effect on the sequestration of integrins in raft-mimicking lipid mixtures.1,2 These experimental findings can be explained on the basis of hydrophobic matching arguments and domain-specific lipid packing conditions. The described model membrane approach is also applied to investigate the oligomerization and sequestration behavior of GPI-anchored urokinase plasminogen activator receptor (uPAR). Here native ligands, but not cholesterol content, were found to impact dimerization level and sequestration of uPAR in raft-mimicking lipid mixtures.3 Corresponding experiments on mixtures of integrins and uPAR also illustrate the formation of integrin-uPAR complexes with distinct sequestration properties. Notably, these findings support a mechanism, in which GPI-anchored proteins cause the translocation of transmembrane proteins to lipid rafts.1) Siegel, A. P. et al. (2011) Biophys. J. 101, 1642.2) Hussain, N. F. et al. (2013) Biophys. J. 104, 2212.3) Ge, Y. et al. (2014) Biophys. J. (in press).
Divestiture Restructuring in the Media Industries: A Financial Market Case Analysis

Much attention has been paid to restructuring in the media industries. Most of this attention has been directed at mergers and acquisitions and the associated increase in industry concentration. What has been largely overlooked is the extent of restructuring that reduces the size of media firms—divestitures. This article examines several cases of major media divestitures and calibrates the impact of these sell-off and spin-off restructuring events on the value of divesting firms. The analysis uses case studies and event study methodology. Given that the overall role of managers of large firms is to maximize the value and stock price, this event methodology directly measures the impact of divestitures on this ultimate goal of maximizing firm value. Case analysis examines the managerial strategies that motivated the divestiture event to explore the complexities of the divestiture as it unfolded. Event analysis results confirm abnormal returns that have the potential to significantly enhance the value of divesting firms. ACCESS TO FULL TEXT
An update-based step-wise optimal cache replacement for wireless data access

Many network applications requires access to most up-to-date information. An update event makes the corresponding cached data item obsolete, and cache hits due to obsolete data items become simply useless to those applications. Frequently accessed but infrequently updated data items should get higher preference while caching, and infrequently accessed but frequently updated items should have lower preference. Such items may not be cached at all or should be evicted from the cache to accommodate items with higher preference. In wireless networks, remote data access is typically more expensive than in wired networks. Hence, an efficient caching scheme considers both data access and update patterns can better reduce data transmissions in wireless networks. In this paper, we propose a step-wise optimal update-based replacement policy, called the Update-based Step-wise Optimal (USO) policy, for wireless data networks to optimize transmission cost by increasing effective hit ratio. Our cache replacement policy is based on the idea of giving preference to frequently accessed but infrequently updated data, and is supported by an analytical model with quantitative analysis. We also present results from our extensive simulations. We demonstrate that (1) the analytical model is validated by the simulation results and (2) the proposed scheme outperforms the Least Frequently Used (LFU) scheme in terms of effective hit ratio and communication cost.
Coronary Artery Bypass Grafting After a Bilateral Lung Volume Reduction Operation

A 67-year-old man underwent coronary artery bypass grafting 31/2 months after a bilateral lung volume reduction operation for end-stage pulmonary emphysema. The principles of anesthetic management we have developed for use during volume reduction operations were applied with success in this individual and are described in detail. With the increasing application of this intervention as an alternative to lung transplantation, we anticipate further experience in the operative management of associated conditions after lung volume reduction operations.
Experience with a Placebo-Controlled Randomized Clinical Trial of a Disease-Modifying Drug for Osteoarthritis: The Doxycycline Trial

Little effort has gone into the development of more effective analgesics for osteoarthritic pain. Efforts to improve symptomatic therapy for osteoarthritis have been deflected or diluted by a decision to pursue the development of disease-modifying OA drugs (DMOADs). These agents' main mechanism of action is directed not at the relief of joint pain but at slowing the progression of structural damage. This article describes the results of a recent randomized placebo-controlled designed to examine the DMOAD effect in humans of the tetracycline antibiotic doxycycline, and reviews the experience gained from other recent DMOAD trials in humans.
Analogues of Vaccinia Virus DNA Topoisomerase I Modified at the Active Site Tyrosine

The mechanism of type IB topoisomerase-mediated DNA relaxation was studied by modification of vaccinia topoisomerase I at the active site tyrosine (position 274) with several tyrosine analogues. These analogues had varied steric, electronic, and stereochemical features to permit assessment of those structural elements required to support topoisomerase function. Eleven tyrosine analogues were successfully incorporated into the active site of vaccinia topoisomerase I. It was found that only tyrosine analogues having the phenolic −OH group in the normal position relative to the protein backbone were active. Modifications that replaced the nucleophilic tyrosine OH (pKa ≈ 10.0) group with NH2 (pKa 4.6), SH (pKa ≈ 7.0), or I groups or that changed the orientation of the nucleophilic OH group essentially eliminated topoisomerase I function. For the active analogues, the electronic effects and H-bonding characteristics of substituents in the meta-position of the aromatic ring may be important in modulating topois...
Determination of the structural requirements for palmitoylation of p63

Abstract Palmitoylation of p63, a type II membrane protein localized in the endoplasmic reticulum, is induced in a reversible manner by the drug brefeldin A. To study the requirements for palmitoylation, mutant forms of p63 were expressed in COS cells and analyzed by metabolic labeling with [3H]palmitate, immunoprecipitation, and SDS-polyacrylamide gel electrophoresis. By investigating deletion and point mutations, Cysin the 106-amino acid cytoplasmic tail of p63 has been identified as the site of acylation. Site-directed mutagenesis of residues 99-105 together with cytoplasmic tail truncation mutants showed that the amino acids surrounding Cysare not critical for palmitoylation of this residue. Analysis of a chimeric construct between p63 and the plasma membrane protein dipeptidylpeptidase IV further revealed that p63 palmitoylation is not dependent on its transmembrane domain. In contrast, the six-amino acid distance between the end of the predicted transmembrane domain and the palmitoylation site was found to be essential for proper acylation of p63.
Comparative testicular toxicity of bis(2-methoxyethyl) ether and 2-methoxyethanol in rats

Male rats were exposed to 0, 110, 370, or 1100 ppm bis(2-methoxyethyl)ether (diglyme) 6 h/day, 5 days/week for 2 weeks. One group of male rats was exposed to 300 ppm 2-methoxyethanol (2-ME) for 2 weeks as a positive control. Exposed rats were killed after 10 days of exposure and 14, 42, or 84 days post-exposure (PE), respectively. At 110 ppm diglyme, spermatocytes in pachytene and meiotic division at spermatogenic stages XII-XIV were mainly affected. At 370 ppm diglyme, affected germ cells were similar to those seen at 110 ppm diglyme, but round spermatids at spermatogenic stages I-VII were also affected. The testes regained normal spermatogenesis by 84 days PE. At 1100 ppm diglyme or 300 ppm 2-ME, marked testicular atrophy was found affecting all spermatogenic stages. Damaged seminiferous tubules were lined with regenerating pachytene spermatocytes at 14 days PE and with spermatocytes and round spermatids after 42 days PE. Most but not all testes in rats exposed to 300 ppm 2-ME or 1100 ppm diglyme had normal morphology after 84 days PE. Based on the observation of germ cell damage, spermatozoa population in the epidymal tubules, reversibility of spermatogenesis after various PE periods, testicular toxicity induced by 300 ppm 2-ME was more severe than that seen at 370 ppm diglyme but was slightly less remarkable than that of 1100 ppm diglyme.
On The Short-Period Type II Cepheid Field Stars

Fourier decomposition parameters for the photoelectric light curves of 20 short-period type II Cepheids in the field are compared with the models of Hodson, Cox, and King, also subjected to Fourier analysis. The hydrodynamic light curves display sequences in the Fourier phases very reminiscent of the resonance progressions among classical Population I Cepheids with periods less than 10 days. However a handful of type II models with small radii and relatively high period ratios, P 2/PO, give Fourier phases which do not seem to follow the resonance sequence. Comparing the models with the type II Cepheid observations, we find very good agreement in both the phase-period and phase-phase diagrams. As in the models, there are a number of observed stars which obviously display a resonance progression and others which may not. Thus, based on the Fourier diagrams, we are led to distinguish three classes of short-period type II Cepheids with periods and period ratios as follows: type II S (1~0 ~ P ~ 1%; P 2/Po ~ 0.53); type II M (1~4 ~ Po ~ 2~0; P 2/Po < 0.53); and type II L (P ~ 2~Od; P 2/Po ~ 0.49). An apparent resonance sequence among the II M stars leads us to propose that the resonance center (P2/Po = 0.5) occurs near 2 days, rather than 1.6 days as suggested previously. We discuss the problems posed for theories of stellar and galactic evolution by the existence of disk, halo, and cluster pulsators with very similar light curves. Comparison of our results with the work of Carson, Stothers, and Vemury, Carson and Stothers, and Petersen and Diethelm, finds a number of points of agreement as well as some contradiction. Further calculations and additional observations, particularly CCD photometry of globular cluster Cepheids, will be necessary to resolve these problems. Subject headings: stars: Cepheids stars: pulsation
Convergence rate estimate for a domain decomposition method

We provide a convergence rate analysis for a variant of the domain decomposition method introduced by Gropp and Keyes for solving the algebraic equations that arise from finite element discretization of nonsymmetric and indefinite elliptic problems with Dirichlet boundary conditions in ?2. We show that the convergence rate of the preconditioned GMRES method is nearly optimal in the sense that the rate of convergence depends only logarithmically on the mesh size and the number of substructures, if the global coarse mesh is fine enough.
CD4+ T cells from Copolymer-1 immunized mice protect dopaminergic neurons in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of Parkinson's disease

Adoptive transfer of lymphoid cells from Copolymer 1 (Cop-1) immunized mice leads to T cell accumulation within the substantia nigra, modulation of microglial responses, upregulation of glial cell derived neurotrophic factor, and protection of the nigrostriatum following 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxication. We now demonstrate that T cells isolated from lymph nodes and spleens of Cop-1 immunized animals protect the nigrostriatal system from MPTP-induced neurodegeneration in a dose-dependent manner. CD4+ T cells elicited the most significant neuroprotective response while high titers of anti-Cop-1 antibodies showed no effect. These data further support the use of immunomodulatory strategies for Parkinson's disease.
Norm Entrepreneurs Scandinavia's Role in World Politics

Promising scholarship in international relations is challenging existing approaches by positing the independent effect of `norms' in world politics. This article identifies `Scandinavia' (in its br...
Detector response correction for 3D PET using Bayesian modeling of the location Of interaction

The unknown exact locations of the interaction (LOI) of photons within detector crystals is a major contribution to the loss of resolution in PET imaging. This effect is intensified with larger distances of the objects from the center of the field-of-view of the camera. In this work we propose a method that recover the loss of the resolution due to unknown LOI. The new method is an unique approach defined in Bayesian framework where the LOIs for two annihilation photons are modeled within the crystal volumes in which they were detected. LOI for each detected event is modeled independently, therefore that method works for binned and list-mode data. The approach was implemented for the minimum-mean-square-error (MMSE) estimator of the number of emissions per voxel. The Markov Chain Monte Carlo origin ensemble algorithm to find the estimator from the projection data was used. We performed computer simulations in 3D using Monte Carlo software of the data acquisitions and simulated Siemens Biograph PET scanner. We used small hot lesion phantom with nine 0.5 cm in diameter spheres placed in warm background. We found that compared to reconstructions with known LOIs for which we assumed that no loss of resolution occurred due to unknown LOI, the correction method proposed in this paper recovered the contrast for investigated object positioned in the center of the scanner. The contrast was only 80% recovered for the phantom positioned off-center due to suboptimal modeling of the LOIs. As expected, an increase in apparent noise in the reconstructed image was observed. This was especially evident for the background region. The method is a novel approach that can be used to improve the spatial resolution of images obtained by PET scanners. The method is directly applicable to time-of-flight PET.
More than the sum of their parts: Martha Rogers and Hildegard Peplau

Nursing practice is guided by a variety of theoretical models. Therefore, nursing theories are commonly selected by service institutions to focus practice. Both Rogers and Peplau made major contributions to the theory and practice of nursing, and both are appropriate models for the discipline of psychiatric and mental health nursing. This article explores the grand theory of Martha Rogers in conjunction with the use of the middle-range theory of Hildegard Peplau. Points of resonance, theoretical fit, and differences between theories are discussed. Appropriateness to practice of both theories are identified and the need for both perspectives is articulated.
Optimal Medical Therapy vs CT Angiography Screening for Patients With Diabetes

discretion of the clinician. The primary end point was the composite outcome of all-cause mortality, nonfatal myocardial infarction, and hospitalization for unstable angina. At a mean follow-up of 4 years, the primary end point occurred in 6.2% of patients (28 events) in the CCTA group and in 7.6% patients (34 events) in the control group (HR, 0.80 [95% CI, 0.49-1.32]; P = .38). Follow-up was 99% complete. Abnormal findings on CCTA in the patients randomized to imaging was associated with subsequent cardiac events, consistent with previous literature. The negative results of this trial will be disappointing to
The vibration of a simply supported rectangular elastic plate due to piezoelectric actuators

Abstract An analysis of a simply supported rectangular elastic plate forced into bending vibrations by the application of time harmonic voltages to piezoelectric actuators attached to its bottom and top surfaces is performed by using the equations of linear elasticity. The actuators have been modeled as thin surface films and mixed edge conditions are employed to simulate simple supports.
An improved procedure for the two carbon homologation of esters to α, β-unsaturated esters

Abstract Treatment of esters with diisobutylaluminum hydride (DIBAL) in the presence of lithio-trialkylphosphonoacetate results in improved yields of the homologated α, β-unsaturated esters. The problematic overreduction, which has previously observed in the half reduction of esters using DIBAL, is minimal (
Immunochemical Analysis of the α-Subunit of the Stimulatory G-Protein of Adenylyl Cyclase in Patients with Albright's Hereditary Osteodystrophy*

Albright's hereditary osteodystrophy (AHO) is an autosomal dominant disorder characterized by an unusual phenotypic appearance and reduced biological activity of the asubunit of the stimulatory G-protein of adenylyl cyclase (G8α). In most AHO patients deficient G8α activity is associated with generalized target organ resistance to hormones that act via stimulation of adenylyl cyclase. This form of the disorder is termed pseudohypoparathyroidism type la (PHP Ia). By contrast, other patients with G8α deficiency fail to demonstrate clinical evidence of hormone resistance and are considered to have the related disorder pseudopseudohypoparathyroidism (pseudoPHP). Previous studies demonstrating deficient G8α bioactivity in cell membranes from patients with AHO used functional assays that were unable to distinguish between reduced amounts of normal G8α protein and normal amounts of defective G8α protein. In the present study we used specific G8α antisera to analyze immunoactive G8α protein in erythrocyte and fib...
Smoothed Linear Modeling for Smooth Spectral Data

Classification and prediction problems using spectral data lead to high-dimensional data sets. Spectral data are, however, different from most other high-dimensional data sets in that information usually varies smoothly with wavelength, suggesting that fitted models should also vary smoothly with wavelength. Functional data analysis, widely used in the analysis of spectral data, meets this objective by changing perspective from the raw spectra to approximations using smooth basis functions. This paper explores linear regression and linear discriminant analysis fitted directly to the spectral data, imposing penalties on the values and roughness of the fitted coefficients, and shows by example that this can lead to better fits than existing standard methodologies.
The ISSN as Identifier and as Linking Mechanism: An Interview with Françoise Pellé

AbstractIn this installment of Serial conversations, MIT cataloger Benjamin Abrahamse talks with Fran§oise Pell©, head of the International ISSN Centre, about the role played by International Standard Serial Numbers (ISSN) in facilitating the identification and collocation of serial publications in a networked environment.
Pharmaceutical Therapies for Sealing of Permeabilized Cell Membranes in Electrical Injuriesa

ABSTRACT: Several years ago, we proposed that loss of cell membrane structural integrity by electroporation is a substantial cause of tissue necrosis in victims of electrical trauma. 1 Specifically, this involves the permeabilization of the lipid bilayer by thermal and electrical forces. We further suggested that certain mild surfactants in low concentration could induce sealing of permeabilized lipid bilayers and salvage of cells that had not been extensively heat-damaged. Successful restoration of membrane transport properties using the surfactant poloxamer 188 was reported in 1992. 2 The purpose of this study is to further examine the response of electroporated rat skeletal muscle membranes to poloxamer 188 (P188) therapy by direct assay of membrane transport properties. Experimental evidence accumulated to date suggests that P188 is effective in sealing permeabilized cell membranes both in vitro and in vivo.
Nitrate Uptake by Reef Corals

In specimens of the hermatypic coral species Fungia scutaria and Montipora verrucosa and in the alga Ulva lactuca, nitrate uptake was measured in light and dark with a flow-through apparatus. The nitrate uptake was measurable in high-nitrate bay water of Kaneohe Bay and also in low-nitrate open ocean water. Nitrate consumption rates by the corals and the alga did not differ from light to dark. Neither the coral nor the alga showed measurable immediate nitrate uptake in open ocean water of low nitrate concentration when they had been held previously in the high-nitrate bay water. In low-nitrate open ocean water the uptake per unit time increases when the flow of the water increases. The uptake of nitrate by reef corals even from low concentrations indicates nonspecific nutrient sources for reef corals.
Ocean disposal of CO2 at intermediate depths

One option to reduce atmospheric CO2 levels is to capture and sequester power plant CO2. Commercial CO2 capture technology, though expensive, exists today. However, the ability to dispose of large quantities of CO2 is highly uncertain. The deep ocean is one of only a few possible CO2 disposal options (others are depleted oil and gas wells or deep, confined aquifers) and is a prime candidate because the deep ocean is vast and highly unsaturated in CO2. The term disposal is really a misnomer because the atmosphere and ocean eventually equilibrate on a timescale of 1000 years regardless of where the CO2 is originally discharged. However, peak atmospheric CO2 concentrations expected to occur in the next few centuries could be significantly reduced by ocean disposal. The magnitude of this reduction will depend upon the quantity of CO2 injected in the ocean, as well as the depth and location of injection. From ocean scale mathematical models which compare the impact of releasing fossil-fuel CO2 into the ocean at various depths1–4, we conclude that a sequestration depth of about 1000 m is required to achieve desired residence times on the order of hundreds of years. Below we summarize several modes of CO2 injection which have been identified in the literature. All offer advantages and disadvantages. We conclude that the most feasible initial options will involve a release of liquid CO2 at intermediate depths of 1000 to 1500 m. Either an unconfined release leading to a buoyant droplet plume or a confined release leading to a dense CO2-seawater solution would work. The intermediate discharge depth represents a compromise between the depth of ultimate sequestration, current engineering technology and national jurisdiction limits. We outline steps toward implementation of these options, including needed studies on injector design, transport and costs, site selection and environmental and legal considerations.
Evaluation of beta defensin 2 production by chicken heterophils using direct MALDI mass spectrometry.

Beta defensins (BD) are cysteine rich, cationic antimicrobial peptides (AMP) produced mainly by epithelial and myeloid cells such as neutrophils. In birds, the neutrophil equivalent heterophils produce avian beta defensins (AvBD) of which AvBD2 is the major isoform. Heterophils recognize pathogens or their derived products through a series of pattern recognition receptors called toll-like receptors (TLR) leading to their antimicrobial activities. This work is the first report of TLR modulation of AvBD2 expression in chickens. To measure the effect of TLR activation on AvBD2 production, the heterophils were cultured with different TLR agonists for 6 h. Modulation of AvBD2 levels by TLR activation was measured using direct MALDI mass spectrometry without stable isotopic labeling or chromatographic separation. Chemical modification of the conditioned media was performed using reduction/alkylation with dithiothreitol/iodoacetamide to distinguish TLR treated AvBD2 (reduced/alkylated) from controls (non-reduced). Changes in corrected ion intensity ratios were assumed to reflect AvBD2 modulation in heterophils upon activation with different TLR agonists. In general, TLR agonists increased AvBD2 production with LPS showing the greatest induction and CpG-ODN showing little or no effect. These data show that the direct MALDI-MS coupled with reduction/alkylation may provide a rapid relative quantitative approach to the measurement of agonist-induced differential expression of AvBD2.
Measuring Shared Team Mental Models: A Meta-Analysis

Although shared team mental models are believed to be important to team functioning, substantial interstudy differences in the manner in which mental models are operationalized has impeded progress in this area. We use meta-analysis to cumulate 23 independent studies that have empirically examined shared mental models (SMMs) in relation to team process and performance and test three aspects of measurement as potential moderators: elicitation method, structure representation, and representation of emergence. Results indicate the way in which SMMs are measured and represented at the team level of analysis reveal meaningful distinctions in observed relationships. Specifically, shared mental model operationalization impacts the observed relationship between SMMs and team process; importantly, only methods that model the structure or organization of knowledge are predictive of process. Conversely, while the magnitude of the relationship differed across measurement method, SMMs were positively related to team performance regardless of the manner of operationalization. In summary, knowledge structure is predictive of team process, and both knowledge content and structure are predictive of team performance.
Myoglobin cavities provide interior ligand pathway.

The myoglobin protein binds oxygen and catalyzes NO oxidation. As a key model protein, its dynamics have been well studied by spectroscopy and by crystallography as well as by simulation. Nonetheless, visualization of the mechanism of movement of ligands within myoglobin has been difficult. Coordinates of the A1 and A3 taxonomic spectral states of myoglobin from the 1 Å crystal structure (1a6g) are generated as consistent sets of correlated clusters of residues with A or B crystal alternates. Analysis of cavities in these A1 and A3 conformations clarifies the pathway of ligand motion from distal entry through interior movement to the proximal side of the heme. Cavities opened up by buried alternate conformations link the distal to the proximal side of the heme. Structural conservation highlights the relevance of this pathway to human neuroglobin. Cavity migration via myoglobin crystal alternates provides a specific link of protein structure to protein dynamics and protein function and demonstrates the relevance of substates (discrete disorder) to function for all proteins.
Injection of ions into a quadrupole ion trap mass spectrometer

Abstract High quality mass spectra can be recorded by generating ions using electron impact ionization or laser desorption, and injecting them into a Paul type quadrupole ion trap. Injection is accomplished at energies of 10–25 eV. The injected ions lose kinetic energy to the damping gas (helium, neon, argon or xenon) and are thus trapped. The efficiency of trapping is investigated as a function of the radio frequency voltage for ions of several masses. Trapped ions can be studied in the usual ways, including photodissociation, collisionally activated dissociation and ion/molecule reactions.
Vertical benchmarks for CAD

Vertical benchmarks are complex system designs represented at multiple levels of abstraction. More effective than component-based CAD benchmarks, vertical benchmarks enable quantitative comparison of CAD techniques within or across design flows. This work describes the notion of vertical benchmarks and presents our benchmark, which is based on a commercial DSP, by comparing two alternative design flows.
The game of the name: An examination of linguistic reference after brain damage ☆

Abstract Two aspects of naming have generally been examined in aphasics: the appreciation of a single property of a concept and the ability to use the names of fully elaborated concepts. In applying to aphasics a recently proposed model of semantic organization—one which allows the simultaneous examination of these two aspects—two studies were conducted: Anterior and posterior aphasics were asked (1) to name members of superordinate categories, their responses being converted into prototypicality scores (the degree to which a member of a category resembles an ideal member of that category) and (2) to differentiate between more or less prototypical members of a category and their superordinates. The results revealed that, while anterior and posterior aphasics differ in their use of the names representing fully elaborated concepts, these groups show no differences in terms of the appreciation of a single property of a concept. The implications of these findings for reference were discussed.
Theory of electrophoretic mobility of a polyelectrolyte in semidilute solutions of neutral polymers

An explicit formula is derived for the electrophoretic mobility of a polyelectrolyte molecule in a semidilute solution of neutral polymers in terms of the molecular weight N of a polyelectrolyte, concentration c of neutral polymers, Debye length and solvent quality. The nature of the crossover between different regimes, as c, N, and the salt concentration are varied, is presented. The calculations show that one progressively enters into regimes of no-separation, separation, and no-separation in the electrophoresis of polyelectrolytes as c is increased. If c is very high, one returns to the mechanism of separation in gel electrophoresis.
Receptor Tyrosine Phosphatases Are Required for Motor Axon Guidance in the Drosophila Embryo

The receptor tyrosine phosphatases DPTP69D and DPTP99A are expressed on motor axons in Drosophila embryos. In mutant embryos lacking DPTP69D protein, motor neuron growth cones stop growing before reaching their muscle targets, or follow incorrect pathways that bypass these muscles. Mutant embryos lacking DPTP99A are indistinguishable from wild type. Motor axon defects in dptp69D dptp99A double mutant embryos, however, are much more severe than in embryos lacking only DPTP69D. Our results demonstrate that DPTP69D and DPTP99A are required for motor axon guidance and that they have partially redundant functions during development of the neuromuscular system.
Mechanochemical synthesis of functionalized silicon nanoparticles with terminal chlorine groups

A facile and efficient, one step method using high-energy ball milling (HEBM) to produce chloroalkyl-functionalized silicon nanoparticles is described. HEBM causes silicon wafers to fracture and exposes reactive silicon surfaces. Nanometer-sized, functionalized particles with alkyl-linked chloro groups are synthesized by milling the silicon precursor in presence of an ω-chloroalkyne in either hexene or hexyne. This process allows tuning of the concentration of the exposed, alkyl-linked chloro groups, simply by varying the relative amounts of the coreactants. The silicon nanoparticles formed serve as a starting point for a wide variety of chemical reactions, which may be used to alter the surface properties of the functionalized nanoparticles.
Borrelia burgdorferi lipopolysaccharide and its role in the pathogenesis of Lyme disease

Lipopolysaccharides (LPS) are a constitutive part of the outer wall of gram negative bacteria. Because many of the symptoms of Lyme disease could be explained by a spirochetal LPS we have subjected Borrelia burgdorferi to standard LPS extraction techniques which yielded a LPS which accounted for 1.5-4% of the dry weight. The LPS was very similar to classical gram negative bacterial LPS both chemically and in its biological activities which included pyrogenicity, mitogenicity for lymphocytes and the induction of Interleukin 1 production by macrophages. In addition, the LPS produced an acute inflammatory reaction when injected intradermally into rabbit skin. It could also prepare a skin site for the production of the local Shwartzman reaction. These results show that the Lyme disease spirochete contains a hitherto unknown LPS that is biologically active in vitro and in vivo. It is likely that this molecule plays an important role in the pathogenesis of Lyme disease.
Mouse α1(I)‐collagen promoter is the best known promoter to drive efficient Cre recombinase expression in osteoblast

Cell- and time-specific gene inactivation should enhance our knowledge of bone biology. Implementation of this technique requires construction of transgenic mouse lines expressing Cre recombinase in osteoblasts, the bone forming cell. We tested several promoter fragments for their ability to drive efficient Cre expression in osteoblasts. In the first mouse transgenic line, the Cre gene was placed under the control of the 2.3-kb proximal fragment of the alpha1(I)-collagen promoter, which is expressed at high levels in osteoblasts throughout their differentiation. Transgenic mice expressing this transgene in bone were bred with the ROSA26 reporter (R26R) strain in which the ROSA26 locus is targeted with a conditional LacZ reporter cassette. In R26R mice, Cre expression and subsequent Cre-mediated recombination lead to expression of the LacZ reporter gene, an event that can be monitored by LacZ staining. LacZ staining was detected in virtually all osteoblasts of alpha1(I)-Cre;R26R mice indicating that homologous recombination occurred in these cells. No other cell type stained blue. In the second line studied, the 1.3-kb fragment of osteocalcin gene 2 (OG2) promoter, which is active in differentiated osteoblasts, was used to drive Cre expression. OG2-Cre mice expressed Cre specifically in bone. However, cross of OG2-Cre mice with R26R mice did not lead to any detectable LacZ staining in osteoblasts. Lastly, we tested a more active artificial promoter derived from the OG2 promoter. The artificial OG2-Cre transgene was expressed by reverse transcriptase-polymerase chain reaction in cartilage and bone samples. After cross of the artificial OG2-Cre mice with R26R mice, we detected a LacZ staining in articular chondrocytes but not in osteoblasts. Our data suggest that the only promoter able to drive Cre expression at a level sufficient to induce recombination in osteoblasts is the alpha1(I)-collagen promoter.
Electrodynamics of Josephson junctions

Using the notion of a macrowave function, we show that Josephson radiation arises from oscillations of an overlap charge density localized inside the junction oxide. These oscillations are analogous to those that produce dipole radiation from a two-level atom.