cssi/SciSciGPT-SciSciNet huggingface dataset:
3-Phase Back to Back Active Power Filter for a Multi-Generator Power System with Reduced dc-link Capacitor

A single wye-delta $(\mathrm{Y}-\Delta)$ shunt transformer front-end for a multi generator power architecture has been gain more and more attention. It provides comparable 5th and 7th harmonic elimination performance to the conventional 12-pulse rectifier with a much-reduced transformer size. However, the shunt transformer rectifier is not able to eliminate 11th and 13th harmonics due to its harmonic cancellation mechanism and the harmonic cancellation performance is sensitive to the transformer leakage inductance. In this paper, a back-to-back active front-end is proposed to improve the drawbacks of the existing shunt-type front-end. PI+R compensator is introduced for the current loop and it effectively eliminates up to 19th harmonics in ac mains. Furthermore the relationship between the phase shift angle between the genset-pair and the dc bus voltage ripple is analyzed and the phase-shift angle that minimizes the dc bus voltage ripple is derived to reduce the required bulk capacitor size.The prototype design achieved 3.14 % THD while 96 % and 66 % reduction in weight and overall volume respectively, which makes it extremely beneficial to large-scale industrial and shipboard applications.
Esophageal and Gastrointestinal Microcirculation: Essential for Mucosal Protection, a Target for Injury, and a Critical Component of Injury and Ulcer Healing

Blood flow through the network of mucosal microvessels in the gastrointestinal tract is essential for delivery of oxygen and nutrients to all mucosal constituents. The endothelial cells lining the microvessels, although protected by prostaglandins, are major targets for injury by various noxious factors, such as ethanol, nonsteroidal anti-inflammatory drugs (NSAIDs), ischemia-reperfusion, and free radicals. Endothelial injury results in formation of thrombi, microvascular stasis, and hypoxia, leading to tissue necrosis in the form of erosions or ulcers. Quantitative histologic, Transmission (TEM) and scanning electron microscopy (SEM) studies show that acute mucosal injury such as erosion triggers angiogenesis in the mucosal microvessels bordering necrosis: endothelial sprouting, formation of endothelial tubes ultimately leading to restoration of microvessels in regenerating tissue. The major molecular trigger for the initiation of angiogenesis in injured esophageal and gastric mucosa is accumulation of hypoxia inducible factor-1α (HIF-1α), which activates the genes encoding vascular endothelial growth factor (VEGF), its receptor, and angiopoietins that regulate angiogenesis. During healing of esophageal or gastric ulcers, granulation tissue, consisting of fibroblasts and proliferating endothelial cells forming microvessels, develops at the ulcer base. The newly formed microvessels, supported by fibroblasts and smooth muscle cells, sprout into the ulcerated area and restore the microvasculature in the ulcer scar. The molecular mechanisms stimulating angiogenesis in granulation tissue include activation of HIF-1α, egr-1, and genes encoding basic fibroblast growth factor, VEGF, angiopoietin-1, angiopoietin- 2, their receptors, and cyclooxygenase-2. The latter co-localizes with upregulated VEGF in esophageal and gastric ulcers. The scars of healed ulcers demonstrate prominent microvascular abnormalities detected by cast/SEM and vascular permeability studies. NSAIDs inhibit angiogenesis by interfering with MAP/Erk2 kinase, actin cytoskeleton, and D1 cyclin. Such actions are likely responsible for NSAID interference with ulcer healing. Our studies demonstrated that gene therapy with a single local injection of VEGF and angiopoietin-1 cDNAs stimulates angiogenesis, promotes restoration of microvascular network, and accelerates healing of experimental gastric and esophageal ulcers.
Dinitrophenylation of phosphorylated gizzard myosin. Labelling of the subfragment 1 region.

Chymotrypsin and papain digestion of 3H-labelled dinitrophenylated chicken gizzard myosin, pretreated with the myosin light chain catalyzed phosphorylating system, released a subfragment 1 devoid of its light chains but containing all of the label associated with the thiols of the heavy chain region. This was also the case when myosin was incubated in the presence of the phosphorylating system but without ATP. Dinitrophenylation of a reconstituted actomyosin made from phosphorylated myosin occurred mainly on -SH groups of the heavy chains, in contrast to the predominant modification of the light chains of myosin from a control actomyosin that was treated similarly. Conformatonal changes in myosin may govern, in part, actin-myosin interaction through the phosphorylation of the light chain of Mr 20.000.
Properties of the glucose 6-phosphate-solubilized brain hexokinase. Evidence for a lipoportein complex.

Abstract 1. 1. Glucose 6-phosphate ( Glc -6-P )-solubilized brain hexokinase is part of a large aggregate as shown by its appearance in the void volume upon Sephadex G-200 and Sepharose 4B column chromatography. 2. 2. Thin-layer chromatography of chloroform-methanol (2:1, v/v) extracts indicate the presence of cholesterol, phosphatidylethanolamine and, tentatively, one or more neutral lipid components in the Glc -6-P supernatant but not in a control supernatant prepared by incubation in the absence of Glc -6-P and lacking significant hexokinase activity. 3. 3. The Glc -6-P supernatant has a phosphorus to protein ratio of 9 ± 2 μ g P/mg protein which is in rough agreement with the values reported, in the literature for brain mitochondrial membranes. 4. 4. Mitochondria, rendered lipid deficient by treatment with cold 10 % aqueous acetone, lost 80–95 % of their total hexokinase activity and this activity could be partially restored by incubation with phosphatidylethanolamine but not with phosphatidylcholine nor phosphatidylserine. Complete recovery of activity was obtained in preparations which had lost no more than 60 % of their activity. 5. 5. Digitonin prevents the MgCl2-mediated rebinding of hexokinase to the mitochondrial membrane at concentrations which do not solubilize hexokinase from intact mitochondria.
Measuring Academic Progress: The Course-Credit System in American Higher Education.

The course–credit system in the United States is the standard means of measuring academic work. Typically, an academic degree is the sum of required and other courses measured by the course credit system. Generally, each course consists of 3 credits (the meaning of each credit is one hour of in-class or laboratory work over a 16 week semester). The system is a means of measuring the time spent on study and not the quality of the work. Since the 19th century, the course–credit system has been the major “currency” in American higher education.
On the excitation of the Zenneck surface wave over the ground at 10 MHz

Using a planar earth model the infinite vertical aperture with a Zenneck wave variation is found to excite only the Zenneck wave with no radiation field. The finite vertical aperture excites a field which is similar to the Zenneck wave near the aperture but resembles the usual ground wave at large distances. Numerical results for various aperture heights are given for a frequency of 10 MHz for a homogeneous ground path.
Properties of the Bayesian Knowledge Tracing Model

Bayesian knowledge tracing has been used widely to model student learning. However, the name “Bayesian knowledge tracing” has been applied to two related, but distinct, models: The first is the Bayesian knowledge tracing Markov chain which predicts the student-averaged probability of a correct application of a skill. We present an analytical solution to this model and show that it is a function of three parameters and has the functional form of an exponential. The second form is the Bayesian knowledge tracing hidden Markov model which can use the individual student's performance at each opportunity to apply a skill to update the conditional probability that the student has learned that skill. We use a fixed point analysis to study solutions of this model and find a range of parameters where it has the desired behavior. *Revised version, Feb 2017
Information Acquisition and Behavioral Change: A Social Marketing Application

Previous literature provides insight into the importance of beliefs and other intrapersonal variables for health-related information acquisition and behavioral change. The results of an empirical investigation evidence the unique strengths of the role of core health benefits for each of the multi-level measures. Directions for the development of effective marketing strategey are discussed.
Peritonitis following Endoscopy in a Patient on Peritoneal Dialysis with a Discussion of Current Recommendations on Antibiotic Prophylaxis

Patients on peritoneal dialysis (PD) are at increased risk for peritonitis. We report a case of a patient with end-stage renal disease on continuous ambulatory PD (CAPD) who developed peritonitis within 24 h of upper endoscopy with biopsy and colonoscopy with polypectomy. He had a previous history of peritonitis unrelated to invasive procedures and eventually was transitioned to hemodialysis because of his recurrent peritonitis. The International Society for Peritoneal Dialysis (ISPD) and newly revised American Society for Gastrointestinal Endoscopy (ASGE) guidelines recommend prophylactic antibiotics for CAPD patients undergoing endoscopic procedures. Other guidelines do not address this issue, and there has been limited evidence to support recommendations.
Interpretation of single-site scintillation measurements to estimate F-region drift velocities

A method of estimating ionospheric drift velocities using single-site scintillation measurements is applied to determine a correlation coefficient of 0.55 between magnetic activity and F-region drift velocity near the auroral ionosphere. This method is based on the relationship between the drift velocity and the scintillation spectral breakpoint.
Mossbauer and EPR study of iron in vacuoles from fermenting Saccharomyces cerevisiae.

Vacuoles were isolated from fermenting yeast cells grown on minimal medium supplemented with 40 μM 57Fe. Absolute concentrations of Fe, Cu, Zn, Mn, Ca, and P in isolated vacuoles were determined by ICP-MS. Mossbauer spectra of isolated vacuoles were dominated by two spectral features: a mononuclear magnetically isolated high-spin (HS) FeIII species coordinated primarily by hard/ionic (mostly or exclusively oxygen) ligands and superparamagnetic FeIII oxyhydroxo nanoparticles. EPR spectra of isolated vacuoles exhibited a gave ∼ 4.3 signal typical of HS FeIII with E/D ∼ 1/3. Chemical reduction of the HS FeIII species was possible, affording a Mossbauer quadrupole doublet with parameters consistent with O/N ligation. Vacuolar spectral features were present in whole fermenting yeast cells; however, quantitative comparisons indicated that Fe leaches out of vacuoles during isolation. The in vivo vacuolar Fe concentration was estimated to be ∼1.2 mM while the Fe concentration of isolated vacuoles was ∼220 μM. Mos...
Inactivation of CMY-2 β-lactamase by tazobactam: initial mass spectroscopic characterization

The CMY-2 beta-lactamase, a plasmid determined class C cephalosporinase, was shown to be susceptible to inhibition by tazobactam (K(i)=40 microM). The reaction product(s) of CMY-2 beta-lactamase with the beta-lactamase inhibitor tazobactam were analyzed by electrospray ionization/mass spectrometry (ESI/MS) to characterize the prominent intermediates of the inactivation pathway. The ESI/MS determined mass of CMY-2 beta-lactamase was 39851+/-3 Da. After inactivating CMY-2 beta-lactamase with excess tazobactam, a single species, M(r)=39931+/-3.0, was detected. Comparison of the peptide maps from tryptic digestion of the native enzyme and the inactivated beta-lactamase followed by LC/MS identified two 22 amino acid peptides containing the active site Ser64 modified by a fragment of tazobactam. These two peptides were increased in mass by 70 and 88 Da, respectively. UV difference spectra following inactivation revealed the presence of a new species with a 302 nm lambda(max). Based upon the increase in molecular mass of the tazobactam inactivated CMY-2 beta-lactamase, we propose that during the inactivation of this beta-lactamase by tazobactam an imine is formed. Tautomerization forms the spectrally observed enamine. Hydrolysis generates the covalently attached malonyl semialdehyde, its hydrate, or an enol. This work provides information on the mass of a stable enzyme intermediate of a class C beta-lactamase inactivated by tazobactam and, for the first time, unequivocal evidence that a cross-linked species is not required for apparent inactivation.
The cytoprotective properties of prostaglandin E2 against the toxic effects of actinomycin C on embryonic neural retina cells.

Abstract Prostaglandins (PGs) have been shown to cytoprotect various tissue types against the toxic effects of many chemicals. The mechanism of this protection is poorly understood, but the involvement of cAMP is often implied. Only one previous study examined nervous tissue and PG protection. The present study was designed to determine if PGE 2 affords cytoprotection to a more specific nervous tissue (embryonic neural retina) from the toxicity of actinomycin C (AMC) using a trypan blue exclusion assay. The lowest concentration of PGE 2 (2 × 10 −5 M ) had no effect, but as the concentration increased (3 × 10 −5 M and 5 × 10 −5 M ), PGE 2 did afford protection against AMC in a dose dependent fashion. Theophylline treated cells were not protected, suggesting that cAMP may not be the primary mechanism of protection.
Pythium spp. Isolated from Bermudagrass During Overseed Transitions in Florida and Pathogenicity of Pythium irregulare on Poa trivialis.

ABSTRACT Pythium spp. were isolated from nonoverseeded bermudagrass and from bermudagrass overseeded with cool-season turfgrass species from October 2000 to July 2001 from two sites in Florida. Pythium spp. were isolated from nonoverseeded and overseeded, and fumigated and nonfumigated, bermudagrass plots from October 2001 to July 2002 from one of the two sites. The vast majority of isolates of Pythium spp. were obtained from the bermudagrass, rather than the cool-season turfgrass species (Poa trivialis or Lolium perenne) used as overseed. In the first year at the Ft. Lauderdale site, Pythium graminicola dominated (91% of isolates obtained). In the first year at the Gainesville site, P. graminicola (56% of isolates) and P. irregulare (36%) dominated; however, after fumigation and replanting, P. graminicola comprised only 11% of all isolates. P. irregulare comprised 30% of all isolates, but was found only in nonfumigated plots. A different species, P. ultimum var. ultimum, not isolated in the first year, w...
Membrane-embedded synaptotagmin penetrates cis or trans target membranes and clusters via a novel mechanism

The synaptic vesicle protein synaptotagmin I has been proposed to serve as a Ca(2+) sensor for rapid exocytosis. Synaptotagmin spans the vesicle membrane once and possesses a cytoplasmic domain largely comprised of two C2 domains designated C2A and C2B. We have determined how deep the Ca(2+)-binding loops of Ca(2+).C2A penetrate into the lipid bilayer and report mutations in synaptotagmin that can uncouple membrane penetration from Ca(2+)-triggered interactions with the SNARE complex. To determine whether C2A penetrates into the vesicle ("cis") or plasma ("trans") membrane, we reconstituted a fragment of synaptotagmin that includes the membrane-spanning and C2A domain (C2A-TMR) into proteoliposomes. Kinetics experiments revealed that cis interactions are rapid (< or =500 micros). Binding in the trans mode was distinguished by the slow diffusion of trans target vesicles. Both modes of binding were observed, indicating that the linker between the membrane anchor and C2A domain functions as a flexible tether. C2A-TMR assembled into oligomers via a novel N-terminal oligomerization domain suggesting that synaptotagmin may form clusters on the surface of synaptic vesicles. This novel mode of clustering may allow for rapid Ca(2+)-triggered oligomerization of the protein via the membrane distal C2B domain.
PHA-543613 Preserves Blood–Brain Barrier Integrity After Intracerebral Hemorrhage in Mice

Background and Purpose—Blood–brain barrier disruption and consequent vasogenic edema formation codetermine the clinical course of intracerebral hemorrhage (ICH). This study examined the effect of PHA-543613, a novel α7 nicotinic acetylcholine receptor agonist, on blood–brain barrier preservation after ICH. Methods—Male CD-1 mice, subjected to intrastriatal blood infusion, received PHA-543613 alone or in combination with α7 nicotinic acetylcholine receptor antagonist methyllycaconitine or phosphatidylinositol 3-kinase inhibitor wortmannin. Results—PHA-543613 alone, but not in combination with methyllycaconitine or wortmannin, inhibited glycogen synthase kinase-3β, thus, stabilizing β-catenin and tight junction proteins, which was paralleled by improved blood–brain barrier stability and ameliorated neurofunctional deficits in ICH animals. Conclusions—PHA-543613 preserved blood–brain barrier integrity after ICH, possibly through phosphatidylinositol 3-kinase-Akt–induced inhibition of glycogen synthase kinase...
Perspectives in reductive lanthanide chemistry

Abstract For several decades the reductive chemistry of the lanthanide metals in soluble, fully characterized molecular species has focused primarily on just three elements: europium, ytterbium, and samarium. Recent developments suggest that the reductive chemistry of the lanthanides is likely to expand greatly beyond these three elements in the new millennium and will be a major area of advancement in lanthanide inorganic, organometallic, and coordination chemistry. This paper previews some possibilities in this field.
The effect of germanium on the precipitation and deformation behavior of Al2Li alloys

Abstract The effect of a small addition of germanium on the precipitation and deformation behavior of an AlLi alloy was investigated. Alloys of nominal weight composition of Al2Li and Al2Li0.2Ge were solution heat-treated, quenched, and aged for various times at 473 K. The microstructures and deformation behavior were characterized and the results for the two alloys were compared. The solubility of lithium was increased when germanium was in solid solution; however, lithium decreased the solubility of germanium at 473 K resulting in the formation of small germanium precipitates homogeneously distributed throughout the matrix. These precipitates had a very positive effect on the deformation behavior and ductility of the alloy.
Transmission of symbiotic dinoflagellates through the sexual cycle of the host scyphozoan Linuche unguiculata

Intracellular symbiotic dinoflagellates are associated with the tropical scyphozoan Linuche unguiculata (Swartz, 1788) throughout all stages of the host's life cycle. During sexual reproduction, eggs are released in mucus strands that contain symbiotic dinoflagellates. Fertilization and development take place externally in the water column. Epifluorescence and transmission electron microscopy showed that unfertilized eggs did not contain intracellular algae, but that infection of the developing embryo was generally successful by the 128-cell stage (≃10 h after fertilization at 23° C). However, experiments with artificially provided Cellufluor-labeled algae demonstrated that older embryos and planulae could be infected by algae through at least 24 h post-fertilization, indicating that the L. unguiculata symbiosis represents a “semi-closed” system. This novel mode of symbiont acquisition results in most sexually-produced offspring becoming infected with maternally-transmitted algae during early development, but allows for acquisition of non-maternally-provided algae later in development. Most of the algal symbionts during the early stages of embryonic and larval development are located within ectodermal cells. This is in contrast to the other life-cycle stages of L. unguiculata (i.e., scyphistoma, medusa, ephyra), where symbionts are found within the gastrodermis of the host.
Elemental analysis of non-living particles in picoplankton fractions from oligotrophic lake water

Abstract Electron microscopic (TEM) study of bacterial-sized planktonic fractions recovered from the water column samples of a small oligotrophic lake, consistently showed the presence of non-living organic and inorganic particles as prominent parts of the micro habitat. An all important objective of this work was to determine the composition and possible origins of the minute particles. They were of several morphological types, described by transmission electron microscopic (TEM) appearance as: spherical, oblong, cuboidal, plates and fibrillar. The TEM used in the scanning transmission mode (STEM) in conjunction with the Princeton Gamma Tech (PGT) System 4 energy dispersive X-ray spectrometer (EDX) allowed the determination of the elemental composition of individual particles. The particles referred to as spherical were electron dense and were less than 1 μm in diameter. They were mainly composed of either Fe or Ti but not both. Cuboidal iron particles 37–75 nm in diameter were found in about equal abundance, but they were arranged in chains of individuals. Oblong particles were from 0.18 to 0.2 nm in width to 0.2 to 0.45 μm in length. Most were composed mainly of Ca, S and O but other elemental compositions were observed also. Plates with jagged edges composed of Al and Si were somewhat electron transparent. Both were less than 1 μm in largest dimension. Fibrillar particles were most abundant and were composed of Fe, Si, Cl, K, Na, O and C. They ranged from 90 A to 37 nm in thickness and 1 μm to several μm in length. Particles of planktonic origin were observed with regularity including fragments of diatom cell walls and scales. These particles were composed of Si and O. Hexagonally shaped virus-like particles of several sizes were observed also. The relationship between elements in micro particles and their possible origins are discussed.
1-Alkenes: Ethylene action compounds or ethylene competitive inhibitors in plants

Ethylene, propene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, and 1-dodecene were tested as ethylene action compounds and also as ethylene competitive inhibitors using a pea growth and a banana ripening assay method. Ethylene, propene, and 1-butene gave a growth inhibition ethylene response in etiolated pea seedlings. 1-Pentene, 1-hexane, 1-octene, 1-decene, and 1-dodecene were inactive as ethylene action compounds but were active as competitive inhibitors of ethylene action in peas. 1-Butene was also active as a competitive inhibitor of ethylene action in pea growth. Ethylene and propene gave a typical ethylene ripening response in bananas, but 1-butene did not induce ripening. It did compete with ethylene and inhibited ethylene action in bananas. 1-Pentene, 1-hexene, 1-octene, 1-decene, and 1-dodecene also were inactive in mimicking ethylene action in bananas, but were competitive inhibitors of ethylene action, and their effectiveness increased as the chain length increased. It is clear that ethylene action inducing compounds and ethylene action competitive inhibitors are reaching the receptor, and the binding site does not appear to be restricted.
Myocardial Protection from Permanent Injury during Aortic Cross-Clamping: Effectiveness of Pharmacological Cardiac Arrest Combined with Topical Cardiac Hypothermia

In two groups of animals (6 and 9 dogs), the aorta was cross-clamped 60 and 90 minutes, respectively, during hypothermic cardiopulmonary bypass. Immediately after cross-clamping, pharmacological cardiac arrest was induced by injecting 100 ml of a cold cardioplegic solution into the aortic root. Topical cardiac hypothermia was added. In hearts undergoing 90 minutes of ischemia, a repeat injection of the cardioplegic solution was done at 45 minutes. In 14 dogs (control group), only topical cardiac hypothermia was instituted for myocardial protection during 60 minutes of ischemia. Seven weeks after operation the surviving animals (6 in each group) were killed. Study of myocardial performance failed to demonstrate significant differences among the groups. Microscopic examination of transmural samples taken from anatomically defined sides of both ventricles, disclosed isolated, punctuate subendocardial scars in only 2 hearts of the control group. All the hearts having 90 minutes of pharmacological cardiac arrest and topical cardiac hypothermia exhibited diffuse fibrosis replacing 10 to 20% of the left ventricular myocardium. Extent and incidence of fibrosis were significantly higher in these hearts in comparison to those of the other groups. We conclude that pharmacological cardiac arrest plus topical cardiac hypothermia makes a safe and efficient method of myocardial protection during aortic cross-clamping only if the ischemic intervals is limited to 60 minutes. It cannot prevent permanent myocardial injury if the ischemic arrest is extended to 90 minutes.
Deformation and thermodynamic response for a crack dislocation model of brittle fracture

Abstract Concepts from dislocation and microcrack models are used to define idealized attributes describing the tip region of a crack. The attributes characterize both geometry and deformation; and this identifies a material defect species called a crack dislocation. With the attributes as variables, a scalar density function for each crack dislocation species can be defined. The crack dislocation is different from the common edge or screw species because it creates a new surface area as well as a displacement discontinuity as it propagates through a crystalline lattice. To model the discontinuities, a relative deformation functional is developed which depends on the crack dislocation density function. Since the crack dislocations are the only material defects assumed to contribute deformation discontinuities, the model is for brittle fracture only. The thermodynamic response uses primarily the methodology established by Gibbs. The existence of an internal energy functional is assumed. The methodology results in a definition for a thermodynamic potential for crack dislocation kinetics, a generalization of the Griffith crack propagation concept, and a local measure for the surface strain energy density changes on the crack dislocation line. The equilibrium thermodynamic potential for crack dislocation kinetics introduces a thermodynamic concept to demarcate crack dislocation density transitions from stationary to non-stationary; hence, it provides an incipient fracture criterion that has a thermodynamic basis. For nonequilibrium thermodynamics, the Onsager formalism is used to model the rates and fluxes of the thermodynamic functions.
Low-income housing under “normal” and post-disaster situations: Some basic continuities

Deficient housing conditions for low-income groups is a critical problem in Third World countries. A critically rapid urbanization the result of a massive exodus from the countryside due to unemployment, lack of services, and mechanization of production, as well as to natural increase -has been a predominant phenomenon over the past twenty years. As a consequence, urban housing, public services, and labour markets have been under severe strain. Shanty towns, slums and marginal settlements have rapidly developed, plagued by problems of lack of access to land tenure, high densities, deficient infrastructure, and lack of public services. In some cases, the ~puiation living in subst~d~d conditions in cities is larger than the population of entire countries. For instance, squatters and slum dwellers in Calcutta (1,720,000), Jakarta (1,125,000), and Karachi (811,500), outnumber the total population of some countries.’ Figure 1 gives an idea of the dramatic extent of the deficiencies in two aspects related to the provision of services to housing: water supply and sewerage.2
Measurement and model error assessment of a single-pixel frequency-domain photon migration apparatus and diffusion model for imaging applications

Research into the near-infrared biomedical optical imaging has produced a multitude of inverse imaging algorithms. Recent experience has shown that when these algorithms are tested with experimental data, they falter due to a mismatch between observed and simulated measurements. When considering measurements for imaging, one must consider both measurement and model error. If data is recorded properly, then measurement error tends to be normally distributed with a mean of zero. Model error can be biased and spatially correlated due to inaccuracies in the diffusion approximation, inaccurate parameter estimates, numerical error, and other factors. This contribution discusses trends in the measurement and model error observed from measurements on a single-pixel, frequency domain photon migration system developed for biomedical optical imaging. In order to reduce the model error bias, an empirical approach was applied to find experimental variables that significantly affect it. This approach reduced the mean of the model error on a test data set and produced a slight smoothing effect on its distribution. Image reconstruction attempts show that the modified data set produces an improved image over the image reconstructed from the raw data set. To our knowledge, this is the first time that model and measurement error information have been incorporated into a three dimensional image reconstruction algorithm.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TH‐C‐332‐02: First Implementation of High‐Resolution Dual‐Detector Region‐Of‐Interest Cone‐Beam Computed Tomography (ROI‐CBCT) for a Rotating C‐Arm Gantry System

Purpose: Region‐of‐interest cone‐beam computed tomography (ROI‐CBCT) has the potential to reduce integral dose while providing higher‐resolution data in the ROI. Previous work used rotating object geometries. We have implemented an ROI‐CBCT system on a clinical rotating C‐arm gantry system and have developed methods for combining high‐resolution projection data within the ROI and low‐resolution, low‐dose data outside the ROI. Method and Materials: High‐resolution ROI projection data were acquired of a coronary stent placed in a rabbit using a custom‐made, high‐sensitivity, microangiographic‐fluoroscope (HSMAF) detector (35 micron pixels), attached to the C‐arm of a clinical fluoroscopic gantry. Full field‐of‐view (FFOV), low‐resolution data were acquired at the same dose as the HSMAF (standard‐dose) and at a lower dose using a commercial flat‐panel detector (FPD) (194 micron pixels). HSMAF data were spatially registered with FPD data using cross‐correlation techniques. The lower‐dose FPD pixel values were matched to the HSMAF values using linear regression. During reconstruction, HSMAF data were used within the ROI, while corrected lower‐dose FPD data were used outside the ROI. Reconstructions were performed with HSMAF/lower‐dose‐FPD and standard‐dose‐FPD data using geometric calibration data, Parker weights, a Shepp‐Logan filter, and a Feldkamp algorithm, generating 512 × 512 × 512 volumes (25 micron voxels). Results: The dual‐detector ROI‐CBCT reconstruction exhibits greater detail than that of the FPD alone. The full‐width‐at‐half‐maxima of line profiles of stent struts (100 micron diameter) are approximately 150 and 290 microns for the dual‐detector and FPD data, respectively. No truncation artifacts are visible. The integral dose of the dual‐detector system is 54% that of the standard‐dose FPD for this experiment. Conclusion: High‐resolution 3D images of stents implanted in a rabbit are successfully obtained using a new rotating‐gantry dual‐detector ROI‐CBCT system. Resolution is significantly higher and integral dose is lower with ROI‐CBCT compared to the standard FPD approach. (Support: NIH‐Grants R01‐NS43924, R01‐EB002873, Toshiba‐Medical‐Systems‐Corporation).
The ocular hypertension treatment study.

Methods: One thousand six hundred thirty-six individuals with intraocular pressure (IOP) from 24 to 32 mm Hg in 1 eye and 21 to 32 mm Hg in the fellow eye were randomized to observation or to topical ocular hypotensive medication. Median time of treatment in the medication group was 13.0 years. After a median of 7.5 years without treatment, the observation group received medication for a median of 5.5 years. To determine if there is a penalty for delaying treatment, we compared the cumulative proportions of participants who developed POAG at a median follow-up of 13 years in the original observation group and in the original medication group.
Effect of the Antioxidant N,N′-Diphenyl 1,4-Phenylenediamine (DPPD) on Atherosclerosis in ApoE-Deficient Mice

Apolipoprotein (apo) E-deficient mice develop atherosclerotic lesions that contain epitopes formed during the oxidative modification of lipoproteins, and they demonstrate high titers of circulating autoantibodies against such epitopes, suggesting that this murine strain may provide a model to investigate the atherogenic mechanisms of oxidized lipoproteins (Palinski et al, Arterioscler Thromb. 1994; 14:605-616). To test the hypothesis that lipoprotein oxidation contributes to lesion formation in apoE-deficient mice, we studied the effect of the antioxidant N,N'-diphenyl 1,4-phenylenediamine (DPPD) in mice fed a high-fat diet containing 0.15% cholesterol. Animals were divided into two subgroups matched for sex and plasma cholesterol levels, and DPPD (0.5% wt/wt) was added to the diet of one subgroup. Throughout the 6 months of intervention, DPPD treatment had no significant effect on plasma cholesterol. Plasma levels of DPPD at the end of the experiment were 33.1 mumol/L. As judged by resistance to loss of polyunsaturated fatty acids, lipoproteins (d < 1.019 g/mL) from DPPD-treated animals showed greater resistance to copper-induced oxidation than lipoproteins from control animals. In addition, there was a greater than twofold prolongation of the lag time in the formation of conjugated dienes in the LDL and IDL fractions of DPPD-treated mice. Atherosclerosis was significantly reduced, by 36% in the DPPD-treated mice (14.0 +/- 4.53% of aortic surface area versus 21.9 +/- 11.6%; n = 32; P < .02). These results are consistent with the hypothesis that lipoprotein oxidation contributes to atherogenesis in apoE-deficient mice. However, further studies with other antioxidants are needed to validate this hypothesis.
Visual content highlighting via automatic extraction of embedded captions on MPEG compressed video

Embedded captions in TV programs such as news broadcasts, documentaries and coverage of sports events provide important information on the underlying events. In digital video libraries, such captions represent a highly condensed form of key information on the contents of the video. In this paper we propose a scheme to automatically detect the presence of captions embedded in video frames. The proposed method operates on reduced image sequences which are efficiently reconstructed from compressed MPEG video and thus does not require full frame decompression. The detection, extraction and analysis of embedded captions help to capture the highlights of visual contents in video documents for better organization of video, to present succinctly the important messages embedded in the images, and to facilitate browsing, searching and retrieval of relevant clips.
An O(N) tight-binding study of carbon clusters up to C8640: the geometrical shape of the giant icosahedral fullerenes

Abstract We report an efficient implementation of the Li-Nunes-Vanderbilt conjugate gradient density matrix search method that exploits sparse matrix algorithms for storage and matrix operations. The scheme avoids the N 3 diagonalization bottleneck and scales linearly with the system's size. Benchmarks on large carbon systems indicate that the method becomes faster than diagonalization for small number of atoms (⩽250). Clusters containing thousands of atoms are studied with modest workstation computation resources. We also report geometry optimizations of very large icosahedral fullerenes (up to C 8640 ) which clearly indicate that these clusters have a faceted (polyhedral) geometrical shape.
Viscosity and Temperature Effects on the Rate of Oxygen Quenching of Tris-(2,2′-bipyridine)ruthenium(II)

We compare the bimolecular quenching rate constant (k2) of luminescent tris(2,2′-bipyridine)ruthenium(II) by oxygen in water, ethylene glycol and glycerol as a function of temperature and viscosity to several theoretical models. The Smoluchowski equation with experimentally determined diffusion coefficients produced calculated values that were in the best agreement with experiment. For the less viscous solvent, water, this equation produced a value that was approximately an order of magnitude larger than the experimental value. With an increase in solvent viscosity, the Smoluchowski value approached the experimental value. Using the Smoluchowski equation with calculated diffusion coefficients based on the known radii of the reacting species produced deviations an order of magnitude larger in water and a factor of two or three lower in ethylene glycol and glycerol. If an assumption is made that the radii of both molecules are equal, we have the Stokes Einstein equation, and the only parameters become temperature and viscosity. Using this relationship, the calculated values for water are about a factor of two larger and with ethylene glycol and glycerol about a factor of 6 smaller than experimental data. These results show that bimolecular quenching is a more complex process affected by many parameters such as solvent cage effects in addition to viscosity and temperature.
Gemcitabine associated pseudocellulitis.

An elderly male with metastatic pancreatic adenocarcinoma and no prior history of pedal edema presented with painful, confluent, macular erythema on bilateral lower extremities with grade III lower extremity edema for 1 week following two cycles of gemcitabine. He was afebrile with local warmth and tenderness and a total leukocyte count of 5000 cells/mm3. An initial diagnosis of cellulitis was made after a negative Doppler ultrasound for DVT was completed. The patient was started on cefazolin. However, failure of the antibiotic trial and absent systemic manifestations led to the presumptive diagnosis of gemcitabine associated pseudocellulitis. The symptoms promptly resolved with withdrawal of the offending agent (Fig. 1). Figure 1. Elderly male patient with confluent, macular erythema on bilateral lower extremities with grade III lower extremity edema. Gemcitabine associated pseudocellulitis has typically been described as a radiation recall phenomenon.1,2 Pseudocellulitis is a non-necrotizing inflammation of the dermis and hypodermis, which can perplex clinicians into unwarranted use of antibiotics.3 Treatment involves withdrawal of gemcitabine and symptomatic management with NSAIDs. Cutaneous reactions to gemcitabine are frequent and usually restricted to a self limited rash occurring in 25 % of the patients. Description of livedo reticularis,4 scleroderma like changes,5 sweet’s syndrome6 and TEN have been limited to isolated cases. This case reiterates the need for awareness of chemotherapy associated adverse reactions by internists.
Water quality assessment of the Rio Conchos, Chihuahua, Mexico

A baseline study was conducted to evaluate the overall quality of the Rio Conchos (Chihuahua, Mexico) and to identify those chemical parameters that can best represent the water quality in different segments of the river. Chemical analyses included the measurement of 62 elements at more than 100 sampling stations along the river, in addition to conventional field analyses (e.g., pH, conductivity). Concentrations of these elements are reported and water quality indicators were identified. Based on the element concentration patterns, the segment of the river in which the water quality is most endangered corresponds to that receiving irrigation drain returns near the confluence of the Rio San Pedro. Self-cleaning and dilution processes account for the improvement in water quality observed as the Rio Conchos approaches the Rio Grande.
Statistical estimation of ozone exposure metrics

Data from recent experiments at North Carolina State University and other locations provide a unique opportunity to study the effect of ambient ozone on the growth of clover. The data consist of hourly ozone measurements over a 140 day growing season at eight sites in the US, coupled with clover growth response data measured every 28 days. The objective is to model an indicator of clover growth as a function of ozone exposure. A common strategy for dealing with the numerous hourly ozone measurements is to reduce these to a single summary measurement, a so-called exposure metric, for the growth period of interest. However, the mean ozone value is not necessarily the best summarization, as it is widely believed that low levels of ozone have a negligible effect on growth, whereas peak ozone values are deleterious to plant growth. There are also suspected interactions with available sunlight, temperature and humidity. A number of exposure metrics have been proposed that reflect these beliefs by assigning different weights to ozone values according to magnitude, time of day, temperature and humidity. These weighting schemes generally depend on parameters that have, to date, been subjectively determined. We propose a statistical approach based on profile likelihoods to estimate the parameters in these exposure metrics.
The Gold Plating of Graphite for the Determination of Mercury with Flameless Devices

Flameless atomizers for atomic absorption have greatly extended the sensitivities of atomic absorption measurements for a great many elements. When determining elements in solutions, one generally pipets a small volume into the graphite cups or tubes of the flameless device and dries the solution in the graphite prior to atomization. Mercury determinations by these methods, however, are a greater problem because of the high volatility of mercury and many of its compounds. Very often analysts experience great difficulty in obtaining working curves for mercury when using flameless devices. Standard deviations are often quite large, leaving one with a great deal of uncertainty in the results obtained. We have recently discovered that by plating the inner surface of graphite tubes and cups with a thin layer of gold these problems can be eliminated.
EFFECTS OF CHRONIC NITROGEN ADDITIONS ON UNDERSTORY SPECIES IN A RED PINE PLANTATION

Two plots in a red pine stand at the Harvard Forest, Massachusetts, have been fertilized for 7 yr with 5 g·m−2·yr−1 or 15 g·m−2·yr−1 of N and compared to an unfertilized control to study the effects of chronic N additions on nutrient cycling, plants, and soil. Movement of added N into soils and plant biomass was tracked using additions of an 15N label to the 5 g·m−2·yr−1 and control plots for two of these years. We present data on changes in the understory plant community of these plots. We measured aboveground biomass, density, N and other elemental concentrations, and 15N tracer recoveries to catalogue the effects of the N additions on this community. Nitrogen contents increased while biomass and nutrient cation concentrations decreased in some species. Percent recoveries of 15N tracers were small but detectable. The natural abundances of 15N also increased in a fertilized treatment without tracer additions. Though this forest has not yet reached N saturation by some definitions, it is possible that the...
Bandwidth of a reconfigurable multiple-group multiprocessor system

Abstract This paper discusses the multiprocessor model using multiple bus as the interconnection network is presented. In this model N processors, B buses, and M memory modules are connected in groups. The collapse of one or more of those memory modules, processors, and buses can lead to the loss in the performance of the whole system, if not collapsed completely. A graceful degradable scheme for the reconfiguration of processors is also presented. Thus the system becomes a multiple-group multiple-bus system. The bandwidth of every multiple-bus system is calculated and summed together for the calculation of the entire system bandwidth.
Autoradiographic distribution of bombesin/gastrin-releasing peptide receptors in fetal cortex transplants.

Abstract Bombesin/gastrin-releasing peptide (BB/GRP) receptors were characterized in fetal cortex transplants in the rat. Using in vitro autoradiography techniques, the density of ( 125 I-Tyr 4 )BB grains was low 2 weeks after transplantation but increased 4 weeks after cortex transplantation into the adult rat fourth ventricle. Densitometry analysis of the autoradiograms indicated that ( 125 I-Tyr 4 )BB bound with high affinity ( K d = 5 n M ) to a single class of sites in the transplant tissue. Specific ( 125 I-Tyr 4 )BB binding was inhibited with high affinity by (Tyr 4 )BB but not by NMB (IC 50 values of 3 and 100 n M , respectively). These data suggest that GRP may act as a novel growth factor and play a regulatory role in the development of fetal cortex transplants.
Solar Cells from Mixed SiCi2H2 and SiH4 Plasmas

We have deposited and analyzed solar cells from mixed SiCI2H2/SiH4 plasmas. Intrinsic and doped films were also grown to explain the cell results. The SiCI2H2 cells have lower fill factor and short circuit current density than the SiH4 cells due to the higher defect densities and lower photoconductivities of SiCI2H2/SiH4 material. Cell results showed low VQC if the n-layer was in contact with an i-layer deposited from SiCI2H2/SiH4. A pure silane buffer layer between the i- and n-layers was needed to attain the standard open circuit voltage. The reduced Voc results from a reduced conductivity of phosphorus-doped SiCI2H2/SiH4 material. However, comparison of doped films showed higher conductivities for boron-doped material grown from the SiCI2H2/SiH4 mixture than from pure silane.
Myristylation and polylysine-mediated activation of the protein kinase domain of the large subunit of herpes simplex virus type 2 ribonucleotide reductase (ICP10).

Abstract The amino-terminal domain of the large subunit of herpes simplex virus type 2 (HSV-2) ribonucleotide reductase (ICP10) was previously shown to possess protein kinase (PK) activity that localizes to the cytosolic, cytoskeletal, and plasma membrane fractions. Further studies of the PK domain using computer-assisted sequence analysis have identified a single transmembrane segment and fatty acid incorporation findings indicate that ICP10 is myristylated. Myristylation does not depend on a viral enzyme, since myristic acid is incorporated into ICP10 precipitated from cells transfected with an ICP10 expression vector. It is also incorporated into the 57-kDa protein expressed by the amino-terminal PK expression vector. The myristyl moiety is linked through an amide bond. The basic protein polylysine stimulates the kinase activity and alters its divalent cation requirements resulting in 20- to 40-fold stimulation in the presence of 0.1 m M Mn 2+ . The PK activity is inhibited by antibody to synthetic peptides corresponding to residues 355–369 and 13–26, respectively, located within, and amino-terminal to, the predicted PK catalytic domain.
Nonlinearity in the perception of form.

ofcontrast, rather than to contrast itself. This finding mayleadto a new understanding ofthe way in whichthe visualsystem segregates objects from their backgrounds.Visual patterns were created on the face ofa cathoderay tube monitor (Tektronix608) with an electronic visualdisplay instrument (Milkmanet al., 1980) underthe con­trol of a microcomputer (PDP-11/23). The instrumentproduced a raster display. Each frame ofthe raster con­sisted of256 lines with 256 pictureelements perline. Theframe rate was 270 Hz. The visual stimulator producedfour spatial profiles, which could be mapped into eachofthe 256