cssi/SciSciGPT-SciSciNet huggingface dataset:
Structural specificity of the steroids interacting with calf thymus histones

Abstract Intensive studies are being undertaken by various investigators to elucidate the mechanism of action of hormones. It has been postulated that steroids might act by uncovering gene expression (Karlson, 1965) . Since histones are associated with DNA and inhibit DNA-dependent RNA polymerase ( Stedman and Stedman, 1960 ; Huang and Bonner, 1962 ; Allfrey, Littau and Mirsky, 1963 ) steroids might act by interacting with histones. Sluyser (1966) reported that cortisol was bound with the lysine-poor fraction of calf and rat liver histones. We have observed that steroids do interact with arginine-rich fraction of calf thymus histones (Sunaga and Koide, 1966). The interaction was determined by measuring the specific activities of labeled steroids bound with calf thymus histones upon gel filtration on Sephadex G-25. The purpose of this study was to determine what functional groups on the steroid nucleus influence this interaction.
Molecular modeling and site-directed mutagenesis studies of a phorbol ester-binding site in protein kinase C.

The protein kinase C (PKC) binding site used by PKC activators such as phorbol esters and diacylglycerols (DAGs) has been characterized by means of molecular modeling and site-directed mutagenesis studies. Based upon a NMR-determined solution structure of the second cysteine-rich domain of PKC α, molecular modeling was used to study the structures of the complexes formed between the PKC receptor and a number of PKC ligands, phorbol esters, and DAGs. Site-directed mutagenesis studies identified a number of residues important to the binding of phorbol esters to PKC. Analysis of the molecular modeling and mutagenesis results allows the development of a binding model for PKC ligands for which the precise binding nature is defined. The calculated hydrogen bond energies between the protein and various ligands in this binding model are consistent with their measured binding affinities. The binding site for phorbol esters and DAGs is located in a highly conserved, hydrophobic loop region formed by residues 6-12 and 20-27. For the binding elements in phorbol esters, the oxygen at C 20 contributes most to the overall binding energy, and that at C 3 plays a significant role. The oxygen atom at C 12 is not directly involved in the interaction between phorbol esters and PKC. Out results also suggest that the oxygens at C 9 and C 13 are involved in PKC binding, while the oxygen at C 4 is of minimal significance. These results are consistent with known structure-activity relationships in the phorbol ester family of compounds. Comparisons with the X-ray structure showed that although the X-ray data support the results for oxygens at C 3 , C 12 , and C 20 of phorbol esters, they suggest different roles for oxygens at C 4 , C 9 , and C 13 . Several factors which may contribute to these discrepancies are discussed
The Consistency of Strömgren-β Photometry for Northern Galactic Clusters. IV. Praesepe Revisited and the Pleiades

New Stromgren-β Pleiades data on a zero point defined by the Hyades and Coma are presented. The new data and counterparts from four extant sources are compared to measurements published by Crawford & Perry in 1976. The only statistically significant problem found in this way is a 4 mmag b – y offset obtained from a data set published by McNamara in 1976. Results of similar comparisons published previously for Praesepe are updated by including three additional sets of published data. In this case, comparisons are made to measurements published by Crawford & Barnes in 1969. Two of the data sets (including one published by Joner & Taylor in 1995) yield accordant, statistically significant formal corrections to the b – y, m1, and β measurements of Crawford & Barnes. In addition, results from a third data set are consistent with those derived from the data of Joner & Taylor. However, this pattern is either partly or entirely absent from the offsets yielded by the other three data sets. Because the measurements of Joner & Taylor are still the only ones known to have been derived from direct comparisons among the Hyades, Coma, and Praesepe, it is concluded that the balance of evidence presently favors the offsets obtained from those data. In addition, it is noted that the data of Joner & Taylor do not imply that the data of Crawford & Barnes require corrections that depend on color. With these interim conclusions drawn, it is then suggested that further Praesepe measurements should be brought to bear on the problem.
Photochemical formation of glyoxylic and pyruvic acids in seawater

Abstract Glyoxylic and pyruvic acids were formed when filter-sterilized seawater was exposed to solar radiation. Production rates varied from samples collected from distinctly different regions of the sea. Humic-rich seawater from the Florida Bay exhibited net photochemical production rates (glyoxylate, 27.5 nM/W-h m −2 ; pyruvate, 12.9 nM/W-h m −2 ) that were significantly greater than net production rates for humic-poor water (glyoxylate, 3.1 nM/W-h m −2 ; pyruvate, 1.8 nM/W-h m −2 ) collected in the Gulf Stream. When seawater was not filtered, the concentrations of glyoxylate and pyruvate were found to undergo diurnal variations resulting from an imbalance between biological and photochemical processes. A depth profile of the glyoxylate concentration from several oceanic stations showed a pronounced daytime maximum in the upper 10 m; this finding is consistent with laboratory results that demonstrated that glyoxylate is formed photochemically in seawater. Pyruvate, in contrast, showed no clear trend with depth; its distribution in the water column may be primarily controlled by biological processes rather than by photochemical processes. Biological processes are generally thought to control the spatial and temporal distribution of simple organic metabolites in seawater. Our results show that photochemical processes may also be important in the marine cycling of some biochemical compounds.
Diacylglycerol Kinase δ Modulates Akt Phosphorylation through Pleckstrin Homology Domain Leucine-rich Repeat Protein Phosphatase 2 (PHLPP2)

Discovering proteins that modulate Akt signaling has become a critical task, given the oncogenic role of Akt in a wide variety of cancers. We have discovered a novel diacylglycerol signaling pathway that promotes dephosphorylation of Akt. This pathway is regulated by diacylglycerol kinase δ (DGKδ). In DGKδ-deficient cells, we found reduced Akt phosphorylation downstream of three receptor tyrosine kinases. Phosphorylation upstream of Akt was not affected. Our data indicate that PKCα, which is excessively active in DGKδ-deficient cells, promotes dephosphorylation of Akt through pleckstrin homology domain leucine-rich repeats protein phosphatase (PHLPP) 2. Depletion of either PKCα or PHLPP2 rescued Akt phosphorylation in DGKδ-deficient cells. In contrast, depletion of PHLPP1, another Akt phosphatase, failed to rescue Akt phosphorylation. Other PHLPP substrates were not affected by DGKδ deficiency, suggesting mechanisms allowing specific modulation of Akt dephosphorylation. We found that β-arrestin 1 acted as a scaffold for PHLPP2 and Akt1, providing a mechanism for specificity. Because of its ability to reduce Akt phosphorylation, we tested whether depletion of DGKδ could attenuate tumorigenic properties of cultured cells and found that DGKδ deficiency reduced cell proliferation and migration and enhanced apoptosis. We have, thus, discovered a novel pathway in which diacylglycerol signaling negatively regulates Akt activity. Our collective data indicate that DGKδ is a pertinent cancer target, and our studies could lay the groundwork for development of novel cancer therapeutics.
Temperature dependence of the photoresponse of Halobacterium halobium

The temperature dependence of the phototactic behavior of bacteriorhodopsin-pigmentedHalobacterium halobium was measured separately toward attractive yellow-green and repellent violet light. A switchoff phenomenon was found for the former below ca. 27°C, while the response to the latter was constant down to about 7°C. This agreement between the transition temperature for the attractive photosystem with that observed in vitro for several properties of purple membrane, of which bacteriorhodopsin is the sole protein pigment, supports the idea that the attractive photosystem is associated with bacteriorhodopsin. Conversely, the absence of such a transition for the photosystem controlling photorepulsion confirms the separate identity of the two photosystems.
Creating Explicit Communication in SoC Models Using Interactive Re-Coding

Communication exploration has become a critical step during SoC design. Researchers in the CAD community have proposed fast and efficient techniques for comprehensive design space exploration to expedite this critical design step. Although these advances have been helpful in reducing the design time significantly, the overall design time of the system is still a bottleneck. All these techniques assume the availability of an initial SoC input model with explicit communication, whose quality significantly impacts the effectiveness of the communication exploration techniques. Today, these initial models need to be manually written by engineers, which is tedious, error-prone and time consuming. In fact, our studies on industrial-size examples have shown that about 50% of the communication exploration time is spent on coding and re-coding of the initial specification model. In this paper, we propose an efficient interactive approach to explicit communication creation by automating some of the common coding tasks in specification models for communication exploration. Our results show significant savings in designer time.
Scaling for first-order phase transitions in thermodynamic and finite systems

Scaling behavior for first-order phase transitions can be derived alternatively but consistently from renormalization-group, phenomenological, or finite-size considerations. A general analysis of densities at a renormalization-group fixed point demonstrates that if the coexistence of $p$ distinct phases is possible, then $p$ distinct eigenvalue exponents must equal the spatial dimensionality. This basic eigenvalue (or scaling) exponent condition can also be derived phenomenologically by various arguments not depending on detailed renormalization-group considerations. A scaling description of first-order phase transitions is presented and extended to finite systems with linear dimensions $L$, leading to a rounding proportional to ${L}^{\ensuremath{-}d}$, response-function maxima varying as ${L}^{d}\ensuremath{\propto}N$, and boundary-condition-dependent shifts which may be as large as $\ensuremath{\sim}{L}^{\ensuremath{-}1}$.
Zinc modulation of water permeability reveals that aquaporin 0 functions as a cooperative tetramer.

We previously showed that the water permeability of AQP0, the water channel of the lens, increases with acid pH and that His40 is required (Nemeth-Cahalan, K.L., and J.E. Hall. 2000. J. Biol. Chem. 275:6777-6782; Nemeth-Cahalan, K.L., K. Kalman, and J.E. Hall. 2004. J. Gen. Physiol. 123:573-580). We have now investigated the effect of zinc (and other transition metals) on the water permeability of AQP0 expressed in Xenopus oocytes and determined the amino acid residues that facilitate zinc modulation. Zinc (1 mM) increased AQP0 water permeability by a factor of two and prevented any additional increase induced by acid pH. Zinc had no effect on water permeability of AQP1, AQP4 or MIPfun (AQP0 from killifish), or on mutants of AQP1 and MIPfun with added external histidines. Nickel, but not copper, had the same effect on AQP0 water permeability as zinc. A fit of the concentration dependence of the zinc effect to the Hill equation gives a coefficient greater than three, suggesting that binding of more than one zinc ion is necessary to enhance water permeability. His40 and His122 are necessary for zinc modulation of AQP0 water permeability, implying structural constraints for zinc binding and functional modulation. The change in water permeability was highly sensitive to a coinjected zinc-insensitive mutant and a single insensitive monomer completely abolished zinc modulation. Our results suggest a model in which positive cooperativity among subunits of the AQP0 tetramer is required for zinc modulation, implying that the tetramer is the functional unit. The results also offer the possibility of a pharmacological approach to manipulate the water permeability and transparency of the lens.
On mountain pass type algorithms

We consider constructive proofs of the mountain pass lemma, the saddle point theorem and a linking type theorem. In each, an initial “path” is deformed by pushing it downhill using a (pseudo) gradient flow, and, at each step, a high point on the deformed path is selected. Using these high points, a Palais–Smale sequence is constructed, and the classical minimax theorems are recovered. Because the sequence of high points is more accessible from a numerical point of view, we investigate the behavior of this sequence in the final two sections. We show that if the functional satisfies the Palais–Smale condition and has isolated critical points, then the high points form a Palais–Smale sequence, and—passing to a subsequence—the high points will in fact converge to a critical point.
Source monitoring deficits in patients with schizophrenia; a multinomial modelling analysis

Background Schizophrenia patients, particularly those with symptoms such as thought insertion, passivity experiences and hallucinations, may share an underlying cognitive deficit in monitoring the generation of their own thoughts. This deficit, which has been referred to as 'autonoetic agnosia', may result in the conclusion that self-generated thoughts come from an external source. Previous work supports this notion, yet the statistical approaches that have been used have not enabled a distinction between specific deficits suggesting autonoetic agnosia and more general cognitive dysfunction. Methods Autonoetic agnosia was assessed using source-monitoring paradigms in 28 patients with schizophrenia and 19 control subjects. Multinomial model analyses, which allow the distinction between deficits in recognizing information, remembering its source, and response biases, were applied to the data. Results Schizophrenia patients were impaired in discriminating between words that came from two external sources, from two internal sources, and one internal and one external source. In a condition requiring subjects to distinguish between words they had heard from those they had imagined hearing, when schizophrenic patients did not remember the source of the information, they showed a stronger bias than controls to report that it had come from an external source. Conclusions The application of multinomial models to source monitoring data suggests that schizophrenia patients have source monitoring deficits that are not limited to the distinction between internally-generated and externally-perceived information. However, when schizophrenia patients do not remember the source of information, they may be more likely than controls to report that it came from an external source.
A new paradigm for biospecimen banking in the personalized medicine era.

Banking of high-quality, appropriately consented human tissue is crucial for the understanding of disease pathogenesis and translation of such knowledge into improvements in patient care. Traditionally, tissue banking has been thought of as primarily an academic research activity, but tissue and biospecimen banking is increasingly assuming clinical importance, especially with the advent of genetic and proteomic testing approaches that rely on fresh or fresh frozen tissue. These approaches are part of the revolution in personalized medicine. This revolution’s impact on biorepositories—their mission and day-to-day function—will be profound. Direct patient care will require structuring tissue procurement to become a routine part of patient care. Accordingly tissue banking will expand from its traditional research role in large academic medical centers into the everyday practice of surgical pathology. Successful implementation of this model will require consideration of several financial, medicolegal, and administrative issues.
Band structure measurements and multi‐electron effects (satellites) for nearly‐filled d‐band metals: Fe, Co, Ni, Cu, Ru, and Pd (invited)

Angle‐resolved photoelectron spectroscopy has been used to determine energy band dispersions E(k↘) along symmetry lines. A complete description of the ferromagnetic energy bands of Ni at the X‐point has been obtained. We observed that the ferromagnetic exchange splitting δEex for the d‐like valence bands of Fe, Co, and Ni depends on the symmetry character of the wave functions. In particular, states derived from t2g tight binding orbitals (e.g., Γ25′, X5) exhibit a larger exchange splitting than eg‐derived orbitals (e.g., Γ12, X2). This agrees with theoretical estimates based on self‐energy calculations. The d‐band widths as observed in photoemission are smaller than those determined by ab initio ground state calculations. This effect increases from Fe to Co to Ni, and is small for Cu, Ru and Pd. We correlate this apparent d‐band narrowing to the position and strength of two‐electron excitations which are seen as satellite structures to the valence band emission.
The influence of lumbar extensor muscle fatigue on lumbar-pelvic coordination during weightlifting.

Lumbar muscle fatigue is a potential risk factor for the development of low back pain. In this study, we investigated the influence of lumbar extensor muscle fatigue on lumbar–pelvic coordination patterns during weightlifting. Each of the 15 male subjects performed five repetitions of weightlifting tasks both before and after a lumbar extensor muscle fatiguing protocol. Lumbar muscle electromyography was collected to assess fatigue. Trunk kinematics was recorded to calculate lumbar–pelvic continuous relative phase (CRP) and CRP variability. Results showed that fatigue significantly reduced the average lumbar–pelvic CRP value (from 0.33 to 0.29 rad) during weightlifting. The average CRP variability reduced from 0.17 to 0.15 rad, yet this change ws statistically not significant. Further analyses also discovered elevated spinal loading during weightlifting after the development of lumbar extensor muscle fatigue. Our results suggest that frequently experienced lumbar extensor muscle fatigue should be avoided ...
Dietary Intake in Patients with Acquired Immunodeficiency Syndrome (AIDS), Patients with AIDS‐Related Complex, and Serologically Positive Human Immunodeficiency Virus Patients: Correlations with Nutritional Status

One of the major clinical manifestations of the acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC) is the development of cachexia. This most likely results from a multifactorial interplay of poor diet, malabsorption, and altered metabolism. To assess the potential role of nutrient intake in the development or persistence of malnutrition, a detailed analysis was performed of a 72-hr diet record in clinically stable patients with AIDS (N = 18), ARC (N = 12) and in human immunodeficiency virus (HIV) seropositive controls without significant manifestations of disease (N = 13). Total calorie intake was 39.1 ± 13.2 kcal/kg/day in AIDS patients us 34.6 ± 7.8 kcal/kg/day in ARC patients or 31.9 ± 17.7 kcal/kg/day in HIV seropositive cases (all p = NS). Likewise, mean protein intakes were similar among the groups and exceeded recommended daily dietary allowance (RDA) guidelines. The mean body weight changes from the inception of illness were -11 ± 1% in AIDS, -6 ± 7% in ARC, us +3 ± 2% in HIV...
Complex structure of the membrane nuclease of Streptococcus pneumoniae revealed by two-dimensional electrophoresis☆

Abstract A nuclease of Streptococcus pneumoniae, previously implicated in DNA transport during genetic transformation, was analysed in crude extracts and cell fractions by a novel technique for detecting enzyme activity after gel electrophoresis in the presence of sodium dodecyl sulfate. The nuclease activity corresponded to a polypeptide of 25,000 molecular weight; its absence in mutants defective in DNA transport and its presence in the membrane of normal cells were confirmed. In crude extracts the nuclease was subject to proteolysis; however, the larger proteolytic fragments retained nuclease activity. When protected from proteolysis by addition of α-toluene-sulfonyl fluoride, the membrane nuclease was found by gel filtration to be in a complex with an apparent molecular weight of approximately 250,000. Proteolysis of the complex released both intact and degraded nuclease monomers. The discrete nature of the complex was demonstrated by two-dimensional gel electrophoresis: the first dimension, under native conditions, showed the complex as a single band; the second dimension, in the presence of sodium dodecyl sulfate, allowed identification of the nuclease subunit. A hypothetical model envisages the membrane nuclease complex to be a doughnut-like structure with an aqueous pore through which one strand of DNA passes into the cell as the complementary strand is degraded by the nuclease action.
Morphological changes in polyamide/PVP blends

Dramatic morphological changes have been found in the blend of an aliphatic crystallizable polyamide (nylon 6/6) with trace quantities of a polar non-crystallizable diluent (poly(vinyl pyrrolidone)). The influence of the addition of PVP on the crystal morphology of nylon 6/6 was studied using d.s.c., X-ray (small and wide angle) and hot stage optical microscopy. The addition of the diluent has a dramatic effect on the spherulitic morphology of nylon 6/6 by causing a striking reduction in the nucleation density of spherulites, modification of lamellar organization in spherulites (as evidenced by the occurrence of banding), and modification of interlamellar spacings. Furthermore, the effect of increasing diluent molecular weight was studied, and it was shown to have only a subtle affect on the system.
Multiphoton ionization in superintense, high-frequency laser fields. Stabilization of atomic hydrogen in linearly polarized fields.

This is the second of two papers studying the multiphoton ionization (MPI) in superintense, high-frequency laser fields. They are based on a general iteration scheme in increasing powers of the inverse frequency. To lowest order in the frequency, i.e., the high-frequency limit, the atom is stable against decay by MPI, though distorted. To next order in the iteration, an expression for the MPI amplitude was obtained. In our first paper [preceding paper, Phys. Rev. A 44, 2160 (1991)], an alternative expression for the MPI amplitude was obtained for atomic hydrogen, which is substantially simpler, though somewhat less accurate. In the present paper, we study its consequences for the case of atomic hydrogen in superintense, linearly polarized fields with the emphasis on the ground state. Special attention is paid to the case in which the de Broglie wavelength of the photoelectrons is small with respect to the amplitude of oscillation of the (distorted) electronic cloud. Most importantly, the total decay rate decreases with increasing intensity at given (high) frequency (``high-intensity stabilization''). This condition defines a radiation regime which yields features in sharp contrast to those obtained in weak fields. The angular distributions of photoelectrons are found to be characterized by rapid oscillations with the polar angle, arising from a peculiar way in which outgoing electron waves interfere.At the same time, the overall behavior of the photoelectrons is to be ejected in directions nearly perpendicular to the polarization axis. We have solved the limit of extremely high intensities at fixed, but otherwise arbitrarily chosen, frequency analytically. We find that in ``ultrastrong fields'' the branching ratios for decay by absorption of the various number of photons possible are only weakly dependent on the values of the intensity and frequency of the laser field, yet excess-photon ionization constitutes a sizable part of the decay modes of the atom (typically 30%). At very high intensities, the hydrogen atom tends to stabilize at fixed, but otherwise arbitrarily chosen frequency. The (a priori unexpected) relative stability of the hydrogen atom in ultrastrong fields is explained as a result of ``radiative distortion'' of the electron cloud and ``destructive interference'' of outgoing electron waves. Although the lifetime of the atom turns out to be extremely short for values of the intensity around the atomic unit, for low enough frequencies and very high intensities, it can be remarkably long. Finally, we discuss the problem of how the atom subject to these extreme radiation conditions could be observed experimentally.
Application of GPC to Studies of the Viscose Process. II. The Effects of Steeping and Alkali-Crumb Aging

Abstract Changes in the distribution of degree of polymerization (DP) of cellulose during the steeping and alkali-crumb aging steps of the viscose process have been studied. A dissolving-grade pulp was used, and two mechanisms of degradation—oxidation and hydrolysis—were considered. Alkaline hydrolysis was relatively unimportant during the steeping, the major change in the DP distribution being a result of the much faster oxida-tive degradation. The extent of oxidation was determined by the solubility of oxygen in the alkali solution. Both oxidation and hydrolysis cause degradation during the aging of alkali crumb. Under the conditions used, hydrolysis was a slow, pseudo-first-order reaction, and oxidation a much faster zero-order reaction. Since there was a large difference in the rates of these reactions, the kinetics of degradation approached zero order.
Silicate Dispersion and Mechanical Reinforcement in Polysiloxane/Layered Silicate Nanocomposites

We report the first in-depth comparison of the mechanical properties and equilibrium solvent uptake of a range of polysiloxane nanocomposites based on treated and untreated montmorillonite and fumed silica nanofillers. We demonstrate the ability of equilibrium solvent uptake data (and, thus, overall physical and chemical cross-link density) to serve as a proxy for modulus (combining rubber elasticity and Flory−Rehner theory), hardness (via the theory of Boussinesq), and elongation at break, despite the nonideal nature of these networks. In contrast, we find that tensile and tear strength are not well-correlated with solvent uptake. Interfacial strength seems to dominate equilibrium solvent uptake and the mechanical properties it predicts. In the montmorillonite systems in particular, this results in the surprising consequence that equilibrium solvent uptake and mechanical properties are independent of dispersion state. We conclude that edge interactions play a more significant role than degree of exfoliat...
Yeast α factor is processed from a larger precursor polypeptide: The essential role of a membrane-bound dipeptidyl aminopeptidase

Abstract Alpha factor mating pheromone is a peptide of 13 amino acids secreted by Saccharomyces cerevisiae α cells. Nonmating ("sterile," or ste ) α-cell mutants bearing defects in the STE13 gene do not produce normal α factor, but release a collection of incompletely processed forms (α factor∗) that have a markedly reduced specific biological activity. The major α-factor∗ peptides have the structures H 2 N-GluAlaGluAla-α factor and H 2 N-AspAlaGluAla-α factor. The ste13 mutants lack a membrane-bound heat-stable dipeptidyl aminopeptidase (DPAPase A) that specifically cleaves on the carboxyl side of repeating -X-Ala- sequences. Absence of DPA-Pase A and the other phenotypes of a ste13 lesion cosegregate in genetic crosses. The cloned STE13 gene on a plasmid causes yeast cells to overproduce DPAPase A severalfold. A different cloned DNA segment, which weakly suppresses the ste13 defects, causes overproduction of a heat-labile activity (DPAPase B) by about tenfold. Other experiments indicate that DPAPase A action may be ratelimiting for α-factor maturation in normal α cells.
Spatial and Temporal Distribution of the Cyanotoxin Microcystin-LR in the Lake Ontario Ecosystem: Coastal Embayments, Rivers, Nearshore and Offshore, and Upland Lakes

ABSTRACT Cyanotoxins, a group of hepatotoxins and neurotoxins produced by cyanobacteria, pose a health risk to those who use surface waters as sources for drinking water and for recreation. Little is known about the spatial and seasonal occurrence of cyanotoxins in Lake Ontario and other lakes and ponds within its watershed. Within the embayments, ponds, rivers, creeks, shoreside, and nearshore and offshore sites of Lake Ontario, microcystin-LR concentrations were low in May, increased through the summer, and reached a peak in September before decreasing in October. Considerable variability in microcystin-LR concentrations existed between and within habitat types within the Lake Ontario ecosystem. In general, the average microcystin-LR concentration was two orders of magnitude lower in embayment (mean = 0.084 µg/L), river (mean = 0.020 µg/L), and shoreside (mean = 0.052 µg/L) sites compared to upland lakes and ponds (mean = 1.136 µg/L). Concentrations in the nearshore sites (30-m depth) and offshore sites...
Single particle high resolution spectral analysis flow cytometry.

Background: While conventional multiparameter flow cytometers have proven highly successful, there are several types of analytical measurements that would benefit from a more comprehensive and flexible approach to spectral analysis including, but certainly not limited to spectral deconvolution of overlapping emission spectra, fluorescence resonance energy transfer measurements, metachromic dye analysis, free versus bound dye resolution, and Raman spectroscopy. Methods: Our system utilizes a diffraction grating to disperse the collected fluorescence and side-scattered light from cells or microspheres passing through the interrogation region over a rectangular charge-coupled-device image sensor. The flow cell and collection optics are taken from a conventional flow cytometer with minimal modifications to assure modularity of the system. Results: Calibration of the prototype spectral analysis flow cytometer included wavelength characterization and calibration of the dispersive optics. Benchmarking of the system demonstrated a single particle/cell intensity sensitivity of 2160 MESF of R-Phycoerythrin. Single particle spectra taken with our instrument were validated against bulk solution fluorimeter and conventional flow cytometer measurements. Coefficients of variation of integrated spectral fluorescence intensity of several sets of standard fluorescent microspheres ranged from 1.4 to 4.8% on the spectral system. Spectral discrimination of free versus PI bound to cells is also demonstrated. Conclusions: It is demonstrated that the flow spectrometer has sufficient sensitivity and wavelength resolution to detect single cells and microspheres, including multi-fluorophore labeled microspheres. The capability to use both standard mathematical deconvolution techniques for data analysis, coupled with the feasibility of integration with existing flow cytometers, will improve the accuracy and precision of ratiometric measurements, enable the analysis of more discrete emission bands within a given wavelength range, and allow more precise resolution of the relative contribution of individual fluorophores in multiply-tagged samples, thereby enabling a range of new applications involving the spectral analysis of single cells and particles. © 2006 International Society for Analytical Cytology
Sensor array signal processing via a procrustes rotations based eigenanalysis of the ESPRIT data pencil

The authors propose the procrustes-rotation-based ESPRIT algorithm, PRO-ESPRIT, for estimating characteristic parameters associated with a scene of radiating sources, given data derived from two identical sensor arrays, the X and Y arrays, which are displaced relative to one another. PRO-ESPRIT uses the inherent redundancy built into the ESPRIT array system to compensate for deviations from the ideal array model. This redundancy is manifested by two fundamental properties of the noiseless X and Y data matrices comprising the ESPRIT data pencil: (a) they have the same row space, the signal subspace; and (2) they have the same column space, the source subspace. These properties are utilized by invoking two primary tools: (1) the solution to the procrustes problem for optimally approximating an invariant subspace rotation; and (2) the total-least-squares method for perturbing each of two estimates of a common subspace in a minimal fashion until the two perturbed spaces are the same. >
Observations of shear wave splitting on the southeast flank of Mauna Loa Volcano, Hawaii

We use a combination of particle motion covariance matrix decomposition, particle motion plots, and cross correlation to estimate the polarization and split times of shear wave arrivals from local earthquakes in the Kaoiki and Hilea regions of southern Hawaii. Consistent leading shear wave polarizations and identifiable fast and slow shear wave arrivals were frequently observed. Average delay times for the four arrays vary from 100 to 230 ms. The leading shear wave polarizations at stations in the Kaoiki region agree with the direction of the local maximum horizontal compressive stress, σH, determined from focal mechanism studies and field observations of ground rupture. For the Bird Park (BP) array, in the Kaoiki region, the relationship between delay time and event depth shows evidence for both dominant shallow and weaker pervasive anisotropy. The correlation between delays and event depth is much weaker for the Ainapo (AN) array than for BP, however a smaller slope is apparent. Conservative estimates of the crack densities for the BP and AN arrays are e=12% and e=6%, respectively. In the Hilea region, the leading shear wave polarization for the Punaluu Gulch (PG) array differs by approximately 30° from the direction of σH determined from focal mechanism studies, while the Waihaka Gulch (WG) array shows no predominant polarization direction. No correlation between delay time and event depth was observed for either of the two Hilea arrays.
The architecture of a shared leadership model for health systems strengthening initiatives led by a U.S.-based academic hospital

reporting using healthcare only once in the past six months. Income was also found to be positively associated with increased healthcare expenditures and private healthcare use. Interpretation: Universal healthcare holds promise for improving healthcare equity and access worldwide; however, more research needs to be conducted to understand how equitable universal healthcare systems are. Surveys such as the Brunei Darussalam Health System Survey are difficult to conduct in large countries, however, they offer a key opportunity to gather population input and assess public expectations and perceptions related to universal healthcare. Funding: Data for this project were obtained by RTI International through a contract with The Innova Group and the Brunei Darussalam Ministry of Health. The author received funding from the Duke University Global Health Institute to complete this research study. Abstract #: 02GMHE012
A Multiweek Upper-Division Inorganic Laboratory Based on Metallacrowns.

Metallacrowns are a versatile class of inorganic compounds with uses in several areas of chemistry. Students engage in a multiweek, upper-division inorganic laboratory that explores four different metallacrown compounds: FeIII(O2CCH3)3[9-MCFeIII(N)shi-3](CH3OH)3·3CH3OH, MnII(O2CCH3)2[12-MCMnIII(N)shi-4](C3H7NO)6·2C3H7NO, [(CH3)4N]2{CuII[12-MCCuII(N)shi-4]}·C3H7NO, and MnII(O2CCH3)2[15-MCMnIII(N)shi-5](C5H5N)6·CH3OH. The syntheses are straightforward, and the compounds are characterized by cyclic voltammetry, solid-state magnetic susceptibility, FT-IR, UV–vis, and paramagnetically shifted 1H NMR. Students are provided with a research-like experience in which they can successfully synthesize a metallacrown, conduct a literature search, develop characterization parameters based on departmental resources, interpret experimental results and compare them to the primary literature, analyze the crystallographic structures of the compounds, and finally present an oral seminar detailing their results and analysis.
Inhibition of bovine leukemia virus release by antiviral antibodies.

Peripheral blood lymphocytes from bovine leukemia virus (BLV) infected cattle were grownin vitro with serums from BLV-infected and uninfected cattle, sheep and rabbits. Only serums from infected animals which had antibody to gp 45/55, the major glycoprotein antigen, inhibited the release of virus from the cells. Although viral antigens could be detected in the cells themselves, none were detected in the supernatants of cultures grown with these serums. Normal serums and serums with antibody only to p23, the internal BLV antigen, did not inhibit virus release. To identify the factor responsible for virus release inhibition, 2 inhibitory serums were absorbed with either gp 45/55, p23 or tissue culture cells from BLV-infected and uninfected cell lines. The results indicated that antibody to gp 45/55 is the factor responsible for virus release inhibition.
Solid-State NMR and Computational Chemistry Study of Mononucleotides Adsorbed to Alumina

Solid-state NMR spectroscopy and ab initio computational chemistry are used to determine the structure of the complex formed upon adsorption of the mononucleotide 2‘-deoxyadenosine 5‘-monophosphate (dAMP) to the surface of a mesoporous alumina. In this multi-technique approach, rotational-echo double-resonance NMR results reveal that the phosphate group of dAMP interacts predominantly with octahedrally coordinated aluminum species at the surface, and therefore, adsorption is modeled with both mono- and bidentate sorption of the nucleotide phosphate group with octahedral aluminum. 31P chemical shielding tensors are calculated from the structure of the lowest energy conformations, and these results are compared to tensor values extracted from analysis of spinning-sideband patterns in the experimental 31P cross-polarization magic-angle-spinning NMR spectrum. The chemical shift anisotropy and asymmetry parameter indicate that the binding is via a monodentate, inner-sphere complex.
Controlled deposition of covalently bonded tantalum oxide on carbon supports by solvent evaporation sol-gel process

A simple strategy for covalently attaching Ta2O5 particles onto functionalized graphitic carbon supports has been developed to fabricate hybrid nanocomposites. In this process, tantalum ethoxide was directly reacted with functional groups on the carbon surface to form covalent bonding, which caused the carbonyl stretches of the carbon supports to be blue-shifted to 50-70 cm-1 after Ta2O5 particle deposition. Homogeneously distributed Ta2O5 particles with smaller than 100 nm have been homogeneously deposited on the carbon supports. X-ray diffraction (XRD), FT-IR spectroscopy, and scanning electron microscopy (SEM) have been used to study the formation of Ta2O5/C hybrid structure.
Understanding the Effects of Molecular Crowding on the Structure and Stability of Proteins Using NMR Spectroscopy

Much of the research on biological proteins is performed in vitro (under artificial conditions) involving the isolation of the protein from the cell. The living cell, however, constitutes a very complex system, and a protein's structure and stability may be influenced by its native environment. An understanding of the effects of molecular crowding will provide important information regarding a protein's structure, dynamics, and stability in vivo.This study involves the titration of 15N FGF-1 with various intracellular components (to simulate an in-cell environment) followed by NMR spectroscopy to determine any chemical shift perturbation corresponding to shifting amino acid residues. Fibroblast Growth Factor 1 (FGF-1) is a protein involved in cellular proliferation, wound healing, and cancer development and metastasis. Little information is known regarding FGF-1's interactions inside the cell, as it follows a non-classical secretion pathway. To better understand the role of intracellular proteins on the structure of FGF-1, several experiments were carried out using multi-dimensional NMR spectroscopy; to the FGF-1 sample were added (1) intracellular proteins (from the purification of unlabeled FGF), (2) intracellular proteins and lysozyme, and (3) lysozyme alone (added as a control). HSQC data was obtained at regular intervals and processed using XWIN-NMR and Sparky software. A chemical shift perturbation plot was constructed from the data to show the (individual and combined) effects of the addition of the intracellular proteins and/or lysozyme on FGF-1. The preliminary results of this study indicate that a moderate number of amino acid residues were perturbed with the addition of intracellular proteins. This implies that molecular crowding plays a role in the structural conformation of FGF-1 and possibly other proteins in vivo.
Antifungal properties of perfume oils

The antifungal properties of 30 perfume oils were tested by allowing the organisms to grow in varying concentrations of the oils in vitro. Fifteen of the perfume oils inhibited the growth of all test organisms at concentrations ranging from 1:500 to 1:13,000. The remaining 15 oils inhibited some of the test organisms at concentrations up to 1:11,000. Oil of rose no. 81412 otto type, crab apple blossom, and rose briar were found to possess marked antifungal properties. The dermato-phytes were extremely susceptible to many of the perfume oils at minute concentrations.
Analyzing Tenant Assignment Policies

This paper discusses two popular policies used by housing authorities to assign applicants to housing projects: first available unit and priority assignment policies. The policies are compared according to their abilities to integrate housing projects, applicant assignment probabilities, and mean waiting times. Our results show that priority policies can successfully integrate public housing projects while first available unit policies can exacerbate segregation. These results support the reported empirical performance of these policies. We briefly consider the time necessary to reach steady state for these policies; this is one point of departure for further research.
Computer simulation of metabolism in palmitate-perfused rat heart. II. Behavior of complete model.

Intermediary metabolism in rat hearts perfused with 11 mM glucose plus 1 mM palmitate was simulated by a computer model. Several enzyme submodels in a previous version of the isolated rat heart computer model were improved, and a new fatty acid oxidation pathway model was added. Compartmentation of metabolites in a pseudo-stationary state was calculated, and its implications are discussed, e.g., citrate level may not regulate glycolysis because it is mostly mitochondrial. Citrate synthetase, controlled largely by its inhibitors, is of key importance in regulating fatty acid metabolism. The response of aconitase to the mitochondrial Mg2+ level is of major importance in setting both the mitochondrial citrate and isocitrate levels. Pyruvate dehydrogenase is about 96% in the inactive phosphorylated form, and the active form is also 15% inhibited by products, severely limiting pyruvate oxidation and causing preferential utilization of palmitate as the metabolic fuel. The simulation is consistent with a creatine phosphate shuttle which delivers high energy phosphate to the site of its utilization for mechanical work.
The influence of fuelbed properties on moisture drying rates and timelags of longleaf pine litter

Fire managers often model pine needles as 1 h timelag fuels, but fuelbed properties may significantly change the rate at which needles exchange moisture with the atmosphere. The problem of determining whether moisture loss from fine fuels is being controlled by individual particles or by the fuelbed remains unresolved. Results from this laboratory experiment indicate that first-period timelags of longleaf pine (Pinus palustris Mill.) needles are altered by fuelbed loading and needle arrangement. Timelags of individual needles ranged from 3.3 to 5.3 h; timelags of beds of vertically oriented needles (4.4 to 8.6 h) approximated those of individual particles, but were slightly influenced by loading. Beds of horizontal needles dried with load-dependent timelags that varied from 6.5 to 31.6 h. Fuel loads ranged from 0.04 (for individual particles) to 1.07 kg·m–2. We report a new metric, the area drying rate, which is analogous to a unit-area burning rate. For beds of flat needles, plots of the area drying rate...
Functional mapping of neurons that control locomotory behavior in Caenorhabditis elegans.

One approach to understanding behavior is to define the cellular components of neuronal circuits that control behavior. In the nematode Caenorhabditis elegans, neuronal circuits have been delineated based on patterns of synaptic connectivity derived from ultrastructural analysis. Individual cellular components of these anatomically defined circuits have previously been characterized on the sensory and motor neuron levels. In contrast, interneuron function has only been addressed to a limited extent. We describe here several classes of interneurons (AIY, AIZ, and RIB) that modulate locomotory behavior in C. elegans. Using mutant analysis as well as microsurgical mapping techniques, we found that the AIY neuron class serves to tonically modulate reversal frequency of animals in various sensory environments via the repression of the activity of a bistable switch composed of defined command interneurons. Furthermore, we show that the presentation of defined sensory modalities induces specific alterations in reversal behavior and that the AIY interneuron class mediates this alteration in locomotory behavior. We also found that the AIZ and RIB interneuron classes process odorsensory information in parallel to the AIY interneuron class. AIY, AIZ, and RIB are the first interneurons directly implicated in chemosensory signaling. Our neuronal mapping studies provide the framework for further genetic and functional dissections of neuronal circuits in C. elegans.
Permissive Hypercapnia: Some Equations

To the Editor. —In the article on permissive hypercapnia in the September 28,1994, issue ofThe Journal, 1 the first two equations are incorrect and make the third incorrect also. The correct equations are as follows: This equation tells the user that the exchange ratio (R) effects the result only when inert gas (1—FIO 2 ) is present. This equation shows that the alveolar carbon dioxide partial pressure (PACO 2 ) is independent of the barometric pressure (PB). I point these things out for the sake of accuracy of concept. However, this does not in any way materially change the conclusions reached in the article in question. The animal body is very tolerant of hypercapnia, and prevention of pulmonary barotrauma is indeed important. The subject procedure deserves further study.
Effect of Predictability on Units of Perception and Attribution

Research indicates that persons do not employ a constant unit of perception in processing social information. An experiment investigated effects of varying the predictability of an actor's behavior upon the manner in which observers partitioned it into units of action and made attributions of behavioral causality. Subjects viewed a tape of an actor who behaved either predictably throughout, predictably at first and then unpredictably, unpredictably at first and then predictably, or unpredictably all the time. Subjects divided the actor's behavior into more units (a) when the behavior began unpredictably than when it began predictably and (b) when the pattern of behavior changed (from predictable to unpredictable or vice versa) than when no change occurred. Number of units was positively correlated with dispositional attributions of causality.