cssi/SciSciGPT-SciSciNet huggingface dataset:
Hemozoin: Crystal Engineering Survivability

During the intraerythrocytic stages of malaria infection, the parasite consumes host hemoglobin as a nutrient source, resulting in the liberation of free heme. In order to survive, the malaria parasite utilizes a unique detoxification pathway in which this toxic free heme is converted to the nontoxic biomineral hemozoin. Structurally, hemozoin consists of reciprocal head-to-tail dimeric units of heme bound through propionate O-Fe(III). The propionic acid groups of the heme dimer then hydrogen-bond with other dimers to form the extended crystal. Disruption of this crystallization process results in parasite death, and therefore serves as an important strategy for drug design. Hemozoin formation does not occur spontaneously at a physiologically relevant rate, and identification of the biological mediator of this crystal remained elusive for many years. Although hemozoin has been studied since the 18th century, scientists have only begun to obtain a detailed understanding of the structure and formation of this biomineral in the last 25 years. Current studies strongly support the hypothesis that neutral lipid bodies present within the parasite are the biological template for hemozoin crystallization. When synthetic neutral lipid bodies (SNLDs) were replicated in vitro, it was found that Fe(III)PPIX rapidly accumulates within these SNLDs. Furthermore, the SNLDs have been shown to serve as a kinetically competent site for β-hematin formation (synthetic hemozoin). This new paradigm for hemozoin formation was rapidly translated into an improved high-throughput screening assay that effectively recapitulated the physiological environment and will allow for improved hit to lead development of new antimalarial drugs. Keywords: hemozoin; β-hematin; antimalarial drug discovery; P. falciparum; high-throughput screening; biomineralization; bioinorganic chemistry; malaria; heme; neutral lipid
Reality check- student reflection on groupwork

1 University of Michigan, 4221 Electrical Engineering and Computer Science Department, Ann Arbor, MI 48109 chesneyd@umich.edu Abstract Often, students are asked to function as a group without any training or experience on how to do so. The objective of this study is to assess the effectiveness of students’ groupwork from three views: student perspective regarding overall satisfaction with groupwork; student perspective regarding overall quality of completed assignments; and faculty perspective regarding overall quality of completed assignments. A class of approximately 25 students was divided into groups of 3-4 students in a senior level, software design course in Computer Science. During the semester, students were given four-30 minute vignettes regarding how to function as a group. Finally, the student’s performance (grade received) was compared with their own evaluation of the effectiveness of their group. Also, students were asked to evaluate the vignettes in terms of increasing/improving the productivity of their group. It is expected that students who perceive their group as highperforming will actually receive higher grades. It is expected that the 30 minute vignettes on effective groupwork will improve the quality of submitted work.
Methionine metabolism in mammals: Effects of age, diet, and hormones on three enzymes of the pathway in rat tissues

Abstract A comprehensive survey has been made to determine the effects of age, diet, and hormone administration on the activities of methionine-activating enzyme, cystathionine synthase, and cystathionase in rat tissues. Specific, sensitive assays were employed to measure changes in the levels of these enzymes in liver, kidney, pancreas, and brain. From these studies we concluded that (a) The developmental pattern of each enzyme varied in the several tissues and the patterns of the three enzymes often varied in the same tissue, (b) Many significant, organ-specific changes in the levels of individual enzymes can be effected by dietary and hormone treatments. However, these factors rarely resulted in a parallel change in the three enzymes in one organ or in a single enzyme in all organs, (c) The response of hepatic cystathionine synthase to many of these factors varies markedly from that observed for threonine dehydratase. This provides additional evidence that these two enzyme activities are not properties of a single protein in mammalian liver, (d) There are several possible implications of this study for the treatment of human cystathionine synthase deficiency (homocystinuria).
Development and Testing of a Temperature-Swing Adsorption Compressor for Carbon Dioxide in Closed-Loop Air Revitalization Systems

The air revitalization system of the International Space Station (ISS) operates in an open loop mode and relies on the resupply of oxygen and other consumables from earth for the life support of astronauts. A compressor is required for delivering the carbon dioxide from a removal assembly to a reduction unit to recover oxygen and thereby dosing the air-loop. We have developed a temperature-swing adsorption compressor (TSAC) that is energy efficient, quiet, and has no rapidly moving parts for performing these tasks. The TSAC is a solid-state compressor that has the capability to remove CO2 from a low- pressure source, and subsequently store, compress, and deliver at a higher pressure as required by a processor. The TSAC is an ideal interface device for CO2 removal and reduction units in the air revitalization loop of a spacecraft for oxygen recovery. This paper discusses the design and testing of a TSAC for carbon dioxide that has application in the ISS and future spacecraft for closing the air revitalization loop.
Learning in the Zone: A social constructivist framework for distance education in a 3-dimensional virtual world

Web-based technologies are the medium of choice for most universities as they move their offerings off campus and online. As we continue to move our own programs online we are challenged to consider what elements of our traditional experiences to preserve online, and which ones to modify, and to recognize the impact of the tools we use on our abilities to do so. The social constructivist conceptual framework that guides our college and the 3-dimensional virtual world we have constructed as our online campus for learning to manifest it are described. The result is a distance learning environment that is unlike traditional classroom- or web-based learning environments in important ways. A description of AET Zone is provided and the implications of using a social constructivist framework for designing and delivering an online learning environment are discussed.
Demonstration of a Slow-Light High-Contrast Metastructure Cage Waveguide

We have developed a new type of Si-based 3D cage-like high-contrast metastructure waveguide with both “slow-light” and low-loss properties, which has applications in providing a long time-delay line or a high Q cavity in chip-scale optoelectronic integrated circuits (OEIC). Traditional semiconductor optical waveguides always have high loss when used in a high dispersion (slow-light) region. A preliminary computational model has predicted that there is a slow-light and low propagation loss region within cage-like hollow-core waveguide formed by 4 high-contrast-gratings walls/claddings. Using our new processing technique, we fabricated several such waveguides on a Si wafer with different core sizes/shapes and different HCGs for 1550 operation wavelength. We have conducted experimental waveguide delay test measurements using a short optical pulse which indicate that the group velocity of these metastructure waveguides are in the range of 20- 30% of the speed of the light. Using a waveguide “cut-back” method, we have experimentally determined the propagation loss of these waveguides are in the range of 2-5dB/cm. We are also developing this type of high-contrast metastructure hollow-core waveguide for different operating wavelength/frequency such as THz for different applications.
Induction of cellular cholesterol efflux to lipid-free apolipoprotein A-I by cAMP.

Abstract In the present study apolipoprotein-mediated free cholesterol (FC) efflux was studied in J774 macrophages having normal cholesterol levels using an experimental design in which efflux occurs in the absence of contributions from cholesteryl ester hydrolysis. The results show that cAMP induces both saturable apolipoprotein (apo) A-I-mediated FC efflux and saturable apo A-I cell-surface binding, suggesting a link between these processes. However, the EC 50 for efflux was 5–7-fold lower than the K d for binding in both control and cAMP-stimulated cells. This dissociation between apo A-I binding and FC efflux was also seen in cells treated for 1 h with probucol which completely blocked FC efflux without affecting apo A-I specific binding. Thus, cAMP-stimulated FC efflux involves probucol-sensitive processes distinct from apo A-I binding to its putative cell surface receptor. FC efflux was also dramatically stimulated in elicited mouse peritoneal macrophages, suggesting that cAMP-regulated apolipoprotein-mediated FC efflux may be important in cholesterol homeostasis in normal macrophages. The presence of a cAMP-inducible cell protein that interacts with lipid-free apo A-I was investigated by chemical cross-linking of 125 I-apo A-I with J774 cell surface proteins which revealed a M r 200 kDa component when the cells were treated with cAMP.
Semen Parameters Before and After Transurethral Surgery for Ejaculatory Duct Obstruction

AbstractPurpose: We examined how transurethral resection of the ejaculatory ducts, performed for infertility, affects semen quality in patients with azoospermia and oligo-asthenospermia.Materials and Methods: A retrospective review was done of 46 cases of transurethral resection of the ejaculatory ducts for ejaculatory duct obstruction, confirmed by transrectal ultrasound. Clinical course and semen quality were assessed by semen parameter indications.Results: In 65 percent of the patients transurethral resection of the ejaculatory ducts improved semen quality (greater than a 50 percent increase in total motile sperm count) and 20 percent initiated a pregnancy an average of 6.1 months postoperatively. Statistically significant increases in total motile sperm count were achieved in men with azoospermia and those treated for oligo-asthenospermic indications; the improvement also was shown to be sustainable. Complications occurred in 20 percent of the men.Conclusions: Significant and durable semen quality imp...
Thermal shock of salmon in vivo induces the heat shock protein hsp 70 and confers protection against osmotic shock

Abstract Salmon transferred from freshwater hatcheries to seawater netpens are subjected to osmotic shock which can disrupt biochemical processes and cause stunted growth or death. The present study aimed to determine if heat shock proteins (hsps) induced by exposure of living animals to thermal shock might confer protection against this osmotic challenge. A 66 kDa protein which cross reacted with a monoclonal antibody to mammalian hsp 70, was induced in hepatic and branchial tissue of juvenile salmon subjected to a 15 min heat shock at 26°. De novo synthesis of this protein did not continue beyond the first 3 h of recovery from heat shock, but the newly synthesized protein was stable for at least 12 h. Heat shocked salmon were better able to survive a subsequent severe osmotic challenge (45 ppt). Cross protection against osmotic shock was observed only during a two month period coincident with parr–smolt transformation, when branchial Na+/K+ ATPase activity was elevated. This report is the first to demonstrate protection against osmotic challenge by heat shock in a living animal.
An approach to emulating separable graphs

A technique foremulating multicomputer interconnection networks that are based onseparable graphs (graphs having bounded degree and sublinear multicolor recursive bisectors) is presented. Efficient emulations among interconnection networks are necessary for porting programs designed for one network to another.
Water-influx Modeling of the Svartsengi Geothermal Field, Iceland

In this paper, lumped-parameter models are presented for confined and unconfined liquid-dominated geothermal reservoirs without recharge and compared to production data from the Svartsengi geothermal field in Iceland. They show that recharge or water influx is likely to affect the field's drawdown with time. Three petroleum reservoir water-influx methods are then presented for steady-state, pseudosteady-state, and unsteady-state aquifers encroaching into the geothermal reservoir. History matching shows that the reservoir/aquifer system is best described as unsteady state and radial, with the aquifer boundary taken at infinite distance.
Effect of prolonged coumadin treatment on the production of pulmonary metastases in the rat

To evaluate the effect of prolonged anticoagulant treatment using Coumadin (warfarin sodium) on the production of pulmonary metastases, 455 rats with Walker 256 carcinosarcoma were given either water or Coumadin solution ab lib in addition to their chow. Administration of Coumadin for 10 days resulted in a significant decrease in metastases from 85.8% of the control group to 9.8% of the Coumadin-treated animals (P < 0.001). The survival of these animals also was increased from 3.8% to 42.6% at 9 weeks. No excessive bleeding occurred in any of these animals though the prothrombin time was prolonged more than twice the average value observed in the normal rat.
Installation and axial pullout of suction caissons: numerical modeling.

We outline the development of a computational procedure for finite-element analysis of suction-caisson behavior, highlighting its unique features and capabilities. The procedure is based on a description of clayey soil as a two-phase medium: a water-filled porous solid. Nonlinear behavior of the solid phase is represented by means of a bounding-surface plasticity model. An algorithm is developed for frictional contact in terms of effective normal stress. Furthermore, a special remeshing scheme is introduced facilitating the simulation of the installation process, tracking the caisson penetration path and avoiding numerical complications in the vicinity of the caisson-soil interfaces. To illustrate the use of the proposed computational procedure and examine its validity, complete simulations of available laboratory tests on model suction caissons are conducted. Results are presented and discussed for test-bed preparation (consolidation) followed by caisson installation by self-weight and suction, setup (re...
Chloramphenicol resistance in Micrococcus pyogenes. II. Intermediary metabolism of sensitive and resistant strains.

SummaryResistance to chloramphenicol in M. pyogenes is accompanied by 1) high endogenous respiration, 2) loss of ability to oxidize pyruvate and acetate, and 3) increased formation of lactic acid from glucose. The antibiotic exerts no depressant effect on any of these reactions carried out by a strain sensitive to the drug. Attempts to reconstitute the pyruvate oxidase system of intact cells resistant to the antibiotic have been unsuccessful.
Carbohydrate utilization by the Lyme borreliosis spirochete, Borrelia burgdorferi

Growth kinetic analyses of Borrelia burgdorferi indicated that this bacterium can utilize a limited number of carbon sources for energy: the monosaccharides glucose, mannose, and N-acetylglucosamine, the disaccharides maltose and chitobiose, and glycerol. All of these carbohydrates are likely to be available to B. burgdorferi during infection of either vertebrate and arthropod hosts, enabling development of a model describing energy sources potentially used by the Lyme borreliosis spirochete during its natural infectious cycle.
Could Sequential Residual Centering Resolve Low Sensitivity in Moderated Regression? Simulations and Cancer Symptom Clusters

Multicollinearity constitutes shared variation among predictors that inflates standard errors of regression coefficients. Several years ago, it was proven that the common practice of mean centering in moderated regression cannot alleviate multicollinearity among variables comprising an interaction, but merely masks it. Residual centering (orthogonalizing) is unacceptable because it biases parameters for predictors from which the interaction derives, thus precluding interpretation of moderator effects. I propose and validate residual centering in sequential re-estimations of a moderated regression—sequential residual centering (SRC)—by revealing unbiased multicollinearity conditioning across the interaction and its related terms. Across simulations, SRC reduces variance inflation factors (VIF) regardless of distribution shape or pattern of regression coefficients across predictors. For any predictor, the reduced VIF is used to derive a lower standard error of its regression coefficient. A cancer sample illustrates SRC, which allows unbiased interpretations of symptom clusters. SRC can be applied efficiently to alleviate multicollinearity after data collection and shows promise for advancing synergistic frontiers of research.
The international transmission of eurodollar and US interest rates: A cointegration analysis

Abstract The relationship between US and Eurodollar certificate of deposit (CD) rates for the period 1981–1988 is examined using an error correction model. Results indicate that there is a structural change in the CD rates. In the earlier sub-period (1981–1983), there exists unidirectional causality leading from the domestic to the external markets. In the more recent sub-period (1984–1988), however, significant reverse causality is observed. These results are likely due to expansion in the size of the Eurodollar market and an increase in the volume of Eurodollar futures trading.
Dual floating breakwaters

Abstract A numerical model is developed to investigate the behavior of a pair of flexible, floating breakwaters consisting of complaint, beam-like structures anchored to the sea bed. Each structure is kept under tension by a small buoyancy chamber at the tip, additional stiffness in each case is provided by mooring lines attached to the buoyancy chamber. The fluid motion is idealized as linearized, two-dimensional potential flow and the equation of motion of each breakwater is taken to be that of a one-dimensional beam of uniform flexural rigidity and mass per unit length subjected to a constant axial force. The boundary integral equation method is applied to the fluid domain. Modifications are made to the basic formulation to account for the zero thickness of the idealized structures, and the dynamic behavior of the breakwaters is described through an appropriate Green's function. Numerical results are presented which illustrate the effects of the various wave and structural parameters on the efficiency of the two-breakwater systems as a barrier to wave action. It is found that by adjusting the spacing between the breakwaters acceptable wave reflection characteristics may be obtained even with relatively flexible structures.
Micromagnetic modeling of spin-wave dynamics in exchange-biased permalloy disks

The magnetization dynamics in exchange-biased $12\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ thick micron-sized permalloy disks have been studied using micromagnetic modeling. The magnetization in the permalloy and in the adjacent antiferromagnetic layer are set in a vortex configuration, and the disk is equilibrated in an applied field, which is then released. The behavior of the magnetization has been modeled as a function of both exchange bias strength and applied field, in both the time and frequency domains. We show that the exchange bias increases the curvature of the effective potential confining the vortex and that the gyrotropic frequency of the vortex core motion increases linearly with exchange bias. The eigenmodes of the spin waves to which the field couples are either azimuthal (for an in-plane field) or circularly symmetric (for a perpendicular field), with several orders of modes being visible. For the cicularly symmetric modes, the increase in frequency with exchange bias is in good agreement with an analytical model.
Distribution and regulation of telencephalic aromatase expression in the zebra finch revealed with a specific antibody.

In songbirds, aromatase (estrogen synthase) activity and mRNA are readily detectable in the brain. This neural aromatization presumably provides estrogen to steroid-sensitive targets via autocrine, paracrine, and synaptic mechanisms. The location of immunoreactive protein, however, has been difficult to describe completely, particularly in distal dendrites, axons, and terminals of the forebrain. Here we describe the neuroanatomical distribution of aromatase in the zebra finch by using a novel antibody raised specifically against zebra finch aromatase. The distribution of aromatase-positive somata in the zebra finch brain is in excellent agreement with previous reports. Additionally, this antibody reveals elaborate, spinous dendritic arbors, fine-beaded axons, and punctate terminals of telencephalic neurons that may synthesize estrogen. Some of these axon-like fibers extend into the high vocal center (HVC) and the robust nucleus of the archistriatum (RA) in males and females, suggesting a role for presynaptic aromatization in cellular processes within these loci. Adult males have more aromatase-positive fibers in the caudomedial neostriatum (NCM) and the preoptic area (POA) compared to females, despite the lack of detectable sex differences in the number of immunoreactive somata at these loci. Thus, the compartmentalization of aromatase in dendrites and axons may serve a sexually dimorphic function in the songbird. Finally, in adult males, aromatase expression is down-regulated by circulating estradiol in the hippocampus, but not in the NCM or POA. The distribution of aromatase suggests a role for aromatization in the regulation of pre- and postsynaptic function in steroid sensitive areas of the songbird forebrain.
TU‐D‐304A‐01: Development and Testing of a Novel, 4D Maximum A Posteriori (MAP) Image Reconstruction Algorithm

Purpose: Deformable image registration has been proven to be useful in tracking organ motion for dose calculation using artifact‐free 4D RCCT images. Such methods are challenged in the presence of image artifacts. We present an alternative method which avoids binning artifacts by directly estimating organ deformation during the reconstruction process. Method and Materials: We have developed a maximum a posteriori (MAP) algorithm for tracking organ motion that uses raw time‐stamped data to reconstruct the images and estimate deformations in anatomy simultaneously. Since the algorithm does not rely on a binning process, binning artifacts are avoided. Signal‐to‐noise ratio (SNR) is also increased since the algorithm uses all of the collected data. The increased SNR provides the opportunity to reduce dose to the patient during scanning. This framework also facilitates the incorporation of fundamental physical properties such as the conservation of local tissue volume during the estimation of organ motion. In order to validate the accuracy of the 4D reconstruction algorithm, a phantom study was performed using the CIRS anthropomorphic thorax phantom in a CT scanner. An improvement in image quality was also demonstrated by application of the algorithm to data from a real liver stereotactic body radiation therapy(SBRT) patient. Results: The algorithm accurately estimated the known motion of the anthropomorphic phantom. Additionally, a significant SNR increase was observed when using 4D reconstruction over binning, even for a scan with X‐ray tube current reduced to 10%. Conclusion: A novel method of fully 4D CTreconstruction was presented. The geometric accuracy of the estimated deformation was validated in phantom. A marked improvement in image quality was observed when applying the algorithm to image data from a real liverSBRT patient. The method allows reduction of X‐ray tube current during scanning while simultaneously improving motion estimates for use in dose calculation.
Perspectives on systems biology

Systems biology is a new field in biology that aims at system-level understanding of biological systems, such as cells and organisms. Molecular biology has already made remarkable contribution to our understanding of biological systems, and its current focus is on the identification of genes and the functions of their products; that is, on the components of systems. There is no doubt that molecular biology will progress even faster and finally identify all the components of biological systems. As such a moment approaches, major importance need to be placed on the establishment of methodologies and techniques that enable us to understand biological systems as systems. This paper overviews the field of systems biology.
Effect of complications on mortality after coronary artery bypass grafting surgery: evidence from New York State.

Objective Complications are associated with increased risk of death. The objective of this study is to quantify the increased odds of dying from complications after isolated coronary artery bypass grafting surgery. Methods We conducted a retrospective cohort study using the New York State Coronary Artery Bypass Grafting Surgery Reporting System for all patients undergoing isolated coronary artery bypass grafting surgery in New York State who were discharged between 1997 and 1999 (51,750 patients; 2.20% mortality). We estimated the independent effect of individual postoperative complications on in-hospital mortality after controlling for patient clinical risk factors and demographics. Results The mortality rate for patients without complication was 0.77% versus 16.1% for patients with complications (P Conclusions There is a strong association between postoperative complications and in-hospital mortality. Complications after isolated coronary artery bypass grafting surgery are associated with a 1.4- to 8-fold increase in the odds of death after adjusting for severity of disease and comorbidities. This information might prove valuable to hospitals in their efforts to design quality improvement initiatives and care protocols to improve mortality after coronary artery bypass grafting surgery.
Partial trisomy 11 in a child resulting from a complex maternal rearrangement of chromosomes 11, 12 and 13

A complex structural rearrangement of chromosomes 11, 12 and 13 was found in a normal female who gave birth to an affected child with partial trisomy for the short arm of chromosome 11 and a balanced translocation 12/13. The detailed analysis of the G-banded chromosomes from early metaphases permitted the delineation of new chromosomal bands which in turn proved essential to the identification of this unusual phenomenon.
Cardiac actions of bovine parathyroid hormone (1-34), isoproterenol, and propranolol in turtles.

Abstract 1. In isolated turtle hearts bovine parathyroid hormone (b-PTH) (1–34) stimulated both force of contraction and rate (beats/min) apparently stimulating beats/min to a larger extent. 2. Isoproterenol stimulated both rate and force, perhaps affecting contractile force more. 3. Propranolol alone clearly decreased contractile force and beats/min. 4. Pre-treatment with propranolol removed stimulatory effects of both bPTH (1–34) and isoproterenol. Propranolol's effect on isoproterenol was expected. Its effect on bPTH (1–34) may be related to β-stimulation by PTH or to some other non-specific inhibitory effect of propranolol.
Inhibition of Leuconostoc mesenteroides P-60 by D-tyrosine and its relationship with sodium and potassium content of the medium.

Abstract Evidence for a growth inhibition of Leuconostoc mesenteroides P-60 by the d -isomer of tyrosine has been obtained by comparison of the relative activities of l - and dl -tyrosine for this organism, and by comparison of tyrosine assay results obtained on acid and alkaline hydrolysates of casein and beef round. It has been further found that this inhibition is significantly greater on a conventional medium buffered with both sodium and potassium salts than on one containing all of the buffer salts in the potassium form. Similar studies with Leuconostoc citrovorum 8081 and Lactobacillus delbrueckii 3 indicate that these organisms are neither inhibited nor stimulated significantly by the presence of d -tyrosine, and are therefore to be recommended as more satisfactory assay organisms for tyrosine whenever the d -isomer is involved in the assays.
Early evolution of gas adsorption chromatography. Part I: Displacement development and the beginnings of elution-type investigations

This two-part article reviews the early evolution of gas-adsorption chromatography, before the advent of partition chromatography. After reporting on the early tests to determine the light hydrocarbon content of natural gas and the methodology described by P.Schuftan, the research activities of S. Claesson and C.S.G. Phillips on displacement-type gas-adsorption chromatography and early work on elution-type analysis by G. Damkohler, E. Wicke, E. Glueckauf and G. Hesse are discussed.
On the integral form of the equation of transfer for a homogeneous sphere

Abstract Basic considerations are used to derive the integral form of the equation of transfer relevant to a homogeneous sphere with internal sources as well as external illumination and a specularly and diffusely reflecting surface.
Characterization of the Metallic and Insulating Phase of V2O3 and (V,Cr)2O3 by XANES

We have measured the O 1s x-ray absorption of single crystals and epitaxial films of V 2 O 3 in both metallic and insulating phases. The spectrum exhibits two peaks, the lower (higher) energy peak due to O 2p contributions to the t 2g (e g ) states. The spectra of all samples in the insulating state vary strongly with the angle between the surface normal and the polarization vector of the incident photons while the spectra of metallic samples are almost isotropic. On cooling the single crystal into the insulating phase, the higher energy peak increases in intensity, producing a spectrum similar to that found in the insulating Cr doped and pure V 2 O 3 thin films, although the single crystal is then monoclinic while the films are not This implies that the change in the c/a ratio in the transition, not the lattice distortion, is primarily responsible for the change in electronic properties.
Intracellular spin-trapping of oxygen-centered radicals generated by human neutrophils

Abstract Phagocytosing neutrophils secrete superoxide into a vacuole generally inaccessible for direct study. However, the spin-trapping agent5,5-dimethyl-1-pyrroline- N -oxide (DMPO) enters the cytoplasm of several cell types where it can report free radical species including superoxide and hydroxyl radical. In the present study we employed a variety of experimental conditions to eliminate extracellular ESR signals and/or free radicals generated by stimulated neutrophils so that DMPO adducts reported events inside the cell. We identified a concentration of poly(ethylene glycol)-modified superoxide dismutase that permitted measurement of intracellular superoxide as determined by several criteria. It seems likely that poly(ethylene glycol)-modified superoxide dismutase is too large to enter the neutrophil phagosome. Under these conditions no hydroxyl radical was detected, as would be predicted from earlier studies with spin-trapping. Use of poly(ethylene glycol)-modified superoxide dismutase should allow on-line measurement of phogosomal events, thereby improving our understanding of microbicidal and inflammatory processes.
(2-Acetoxyphenoxy)ethyl (APOE) as a Phosphate Protecting Group in Solid-Phase Synthesis of Oligonucleotides via the Phosphoramidite Approach

The (2-acetoxyphenoxy)ethyl (APOE) group could be an alternative to the conventional 2-cyanoethyl group for phosphate protection in solid-phase oligonucleotide synthesis to circumvent DNA alkylation by acrylonitrile generated under basic condition. This group is stable during oligonucleotide synthesis and can be removed under mild conditions using aqueous ammonium hydroxide. Multiple phosphorothioate oligodeoxyribonucleotides and 2‘-O-methoxyethyl-modified oligoribonucleotide chimera were synthesized and characterized extensively. The deprotection of this group follows an intramolecular attack on the α-carbon adjacent to phosphate oxygen to liberate the oligonucleotide and an innocuous cyclic ether as side product. No modification of nucleobases was observed during deprotection of this group.
The energy well connection graph: a use of curvilinear coordinates to achieve dimension reduction for graph representation of molecular conformation energy data

In the conformation space of a flexible molecule, curvilinear coordinate paths connecting conformations of segments of the given molecule are used to reduce the number of variables required for describing barriers between preferred conformations of the molecule as a whole. The technique is applied to a hypothetical example, then to m-trinuoromethyl-N-ethyl-amphetamine (fenfluramine), and to N-methyl-3-phenyl-3-(o-methoxyphenoxy)-propylamine (nisoxetine). In the latter example, the number of variables is thus reduced from six to three. In all three examples, a graph representation of low-energy well connection is achieved. The limit of easy comprehension has thus been moved back from about three torsion angles to three effective segments. Within this limit the procedure leads to a quantitative diagram, which is no harder to read than a contour map, showing the barriers to low-energy interconnection among the favorable conformations of a moderately complex molecule.
Decreased bioavailable testosterone in aging normal and impotent men.

Tissue available (bioavailable) testosterone (T) includes circulating free T (FT) and albumin-bound T. A reasonable assessment of bioavailable T can be made by using 50% ammonium sulfate to precipitate sex hormone-binding globulin (SHBG)-bound T. The supernatant non-SHBG-bound T (non-SHBG-T) correlates well with physiological androgen activity. To assess bioavailable T in normal aging men, we analyzed serum samples from seven healthy aged men (65-83 yr old) and compared the results to samples from 13 young men (22-39 yr old). Mean serum T, FT, and LH concentrations were not significantly different in the 2 groups. However, the mean absolute non-SHBG-T level was significantly lower (P less than 0.005) in the older group. In a separate population of 20 impotent but otherwise healthy men (5 27-37 yr old, 10 48-64 yr old, and 5 66-69 yr old), the mean absolute non-SHBG-T concentration was lower in middle-aged (P less than .01) and elderly men (P less than 0.001) than in young men. The absolute FT was lower only in the elderly group (P less than 0.05), while mean LH and T levels were similar in all 3 age groups. These data suggest that serum concentrations of tissue available T are decreased in aged men and that non-SHBG-T measurement is a more sensitive indicator of this decrease than are serum T or serum FT measurements. These changes appear to begin by middle age.
Inviscid Stability of Hypersonic Strong Interaction Flow Over a Flat Plate

For the region near the leading edge in the viscous flow over a hypersonic flat plate, limit process asymptotic expansions have been studied for the Navier-Stokes equations that give two primary decks for the flow structure. The limit used for each is equivalent to keeping the Viscous Interaction Parameter χ fixed as the reciprocal of the Reynolds number ∈ → 0. The main focus is to incorporate the simultaneous effects of the finite vertical domain, strong curved shock induced by the effective 3/4 power body corresponding to the boundary layer thickness δ(x) and the stratification of the flow into the stability calculation, where x is the streamwise coordinate. The appropriate equations for the perturbations are obtained with a secondary limit of the amplitude parameter e → 0. Parallel flow approximations and modal factorization of the x dependent part of the disturbances are naturally suppressed in this formulation. The initial-boundary value problem for these quantities is solved numerically by a marching technique. Results indicate that the disturbances generally decay for the specific heat ratio γ = 1.4 for typical initial distributions at the upstream station. On the other hand, amplification occurs with reduced shock layer thickness associated with lower values of γ.
The wake instability in viscoelastic flow past confined circular cylinders

Laser Doppler velocimetry (LDV) and video flow visualization are used to investigate the creeping motion of a highly elastic, constant-viscosity fluid flowing past a cylinder mounted centrally in a rectangular channel. A sequence of viscoelastic flow transitions are documented as the volumetric flow rate past the cylinder is increased and elastic effects in the fluid become increasingly important. Velocity profiles clearly show that elasticity has almost no effect on the kinematics upstream of the cylinder, but that the streamlines in the wake of the cylinder are gradually shifted further downstream . Finite element calculations with a nonlinear constitutive model closely reproduce the evolution of the steady two-dimensional velocity field. However, at a well defined set of flow conditions the steady planar stagnation ow in the downstream wake is experimentally observed to become unstable to a steady, three-dimensional cellular structure. The Reynolds number at the onset of the flow instability is less than 0.05 and inertia plays little role in the flow transition, LDV measurements in the wake close to the cylinder reveal large spatially periodic fluctuations of the streamwise velocity that extend along the length of the cylinder and more than five cylinder radii downstream of the cylinder. Fourier analysis shows that the characteristic spatial wavelength of these flow perturbations scales closely with the cylinder radius R . Flow visualization combined with LDV measurements also indicates that the perturbations in the velocity field are confined to the narrow region of strongly extensional flow near the downstream stagnation point. A second flow transition is observed at higher flow rates that leads to steady translation of the cellular structure along the length of the cylinder and time-dependent velocity oscillations in the wake. Measurements of the flow instability are presented for a range of cylinder sizes, and a stability diagram is constructed which shows that the onset point of the wake instability depends on both the extensional deformation of the fluid in the stagnation flow and the shearing flow between the cylinder and the channel.
Representation of heterogeneity effects in Earth system modeling: Experience from land surface modeling

The land surface is characterized by pronounced spatial heterogeneity that spans a wide range of scales. This heterogeneity affects the surface energy and water budgets, as well as the land-atmosphere exchanges of momentum, heat, water and other constituents, through a number of highly nonlinear processes. The resolution of present-day Earth (or climate) system models is still too coarse to explicitly capture the effects of surface heterogeneity, which therefore needs to be parameterized within the framework of complex and nonlinear land surface process schemes. The effects of surface heterogeneity are here grouped in two categories, which we define as “aggregation” and “dynamical” effects. Models of aggregation effects attempt to calculate the contribution of different subgrid scale surface types to the grid box average energy and water budgets and surface-atmosphere exchanges. Such models have been based on discrete approaches, whereby heterogeneity is described in terms of a finite number of subgrid “tiles” or “patches,” and on continuous approaches, in which heterogeneity is described in terms of probability density functions. Subgrid scale aggregation has been shown to especially affect the surface latent and sensible heat fluxes, the simulation of snow, and the dynamics of soil moisture and runoff. Dynamical heterogeneity effects are associated with microscale and mesoscale circulations induced by heterogeneous surfaces. These circulations can influence boundary layer structure, cloud formation, precipitation, and vertical transfer of momentum, energy, and water up to the midtroposphere. In the last decade or so, the importance of land surface heterogeneity representation has been increasingly recognized in a large number of new studies. This paper reviews and critically discusses different approaches that have been proposed to represent aggregation and dynamical effects of surface heterogeneity and their incorporation in land surface process schemes. Some of the methodologies discussed in this paper are of general nature and therefore can be of interest for problems of subgrid scale process description in other geophysical disciplines.
Bewegingsprogramma’s bij dementie lijken effectief

Context Door de ‘dubbele vergrijzing’ zal de prevalentie van dementie de komende jaren toenemen. De achteruitgang van cognitieve functies is helaas moeilijk te behandelen. Gedragsbeinvloeding en psychologische interventies worden wel toegepast, medicamenteuze behandeling neemt (vooralsnog) een kleine plek in.
Fluorescence probing of the interfaces of solid calcium carbonate, calcium hydroxide, and calcium oxide with benzene and heptane

Abstract IR and fluorescence probing studies have been used to investigate the solid surfaces of CaO, Ca(OH)2, and CaCO3 in contact with benzene. IR studies show that organic acids interact with CaO and Ca(OH)2 to form adsorbed anions, while free acids are adsorbed to CaCO3. Pyrene butyric acid, PBA, binds to the surfaces and the fluorescence of the pyrene chromophore reports back on events at the surface. At least two surface sites exist for PBA on all surfaces, one at the solid-benzene interface and one away from the surface in a cleft or pore. Reactions of excited surface-adsorbed PBA with nitromethane, nitroethanol, and nitropropionic acid, which are also bound to the surfaces, fall into two classes. The first class, exhibited by CaCO3 indicates dynamic quenching where both reactants move on the surface. The second, illustrated by Ca(OH)2, shows static quenching where both reactants are bound on the surface in very close proximity. The studies show marked differences between the various surfaces, which has also been observed in a more limited extent on colloids of these materials in oil.
Using the twelve-lead electrocardiogram to localize the site of origin of ventricular tachycardia.

a ( a h t m n t a w o The basis of this review is the underlying hypothesis that he QRS morphology on 12-lead ECG is, to a great extent, etermined by the site from which a focal ventricular tachyardia (VT) arises or from which a reentrant circuit exits the entral isthmus to activate the “normal” myocardium. The bility to localize or, at the very least, regionalize “the sites f origin” of VTs enables the electrophysiologist to concenrate mapping to a specific region. Several factors limit the bility of the QRS patterns to localize VT origin, including 1) presence and size of infarction, (2) degree of intramyoardial fibrosis, (3) shape of the heart (e.g., aneurysm) and ts position within the chest cavity, (4) site and mechanism f VT within an infarct or scarred area, (5) influence of onuniform anisotropy in affecting propagation from the ite of the tachycardia, (6) effects of acute ischemia, antirrhythmic drugs, or metabolic abnormalities on conducion, (7) integrity of the His-Purkinje system, (8) presence f increased myocardial mass, and (9) presence of structural bnormalities unrelated to tachycardia origin or mechaisms. Despite these limitations, the ECG remains useful at east in regionalizing the origin of VT and provides more ccurate localizing information in the structurally normal eart. Some features on the ECG can give clues to the nderlying substrate. The more rapid the initial forces, the ore likely VT is arising from normal myocardium. Sluring of the initial forces is frequently seen when the tachyardia arises from an area of scar or from the epicardium. Ts originating in very diseased hearts have lower-ampliude complexes than those arising in normal hearts. The resence of notching of the QRS is a sign of scar tissue. hereas QS complexes may be seen in a variety of disorers, the presence of qR or QR or Qr complexes in related eads is highly suggestive of the presence of an infarct. ccasionally it is easier to recognize the presence of infarct uring VT than during sinus rhythm.
Effects of Starch Isolation, Drying, and Grinding Techniques on Its Gelatinization and Retrogradation Properties

ABSTRACT The effects of two different methods of starch isolation, drying, and grinding on gelatinization and retrogradation properties were investigated. Starch was isolated from whole wheat and flour of four hard red spring wheat cultivars. Portions of each starch isolate were freeze-dried or air-dried and portions of each dried starch were ground using a mortar and pestle or a Wiley Jr. mill. Less starch damage was obtained for freeze-dried starch regardless of isolation method or grinding technique and for all starches derived from whole wheat. Highest starch damage was obtained for air-dried starch isolates. Wiley-milled starch isolates showed higher water-binding. Whole wheat starch isolates had higher peak, lower trough, and lower final viscosities, as determined by starch paste viscosity analysis, than did starch isolates derived from flour. Major effects of all treatments on differential scanning calorimetry gelatinization properties showed lower onset temperature for flour starch isolates, lower...
Large area mapping of excised breast tissue by fluorescence confocal strip scanning: a preliminary feasibility study

Lumpectomy, in conjunction with radiation and chemotherapy drugs, together comprise breast-conserving treatment as an alternative to total mastectomy for patients with breast tumors. The tumor is removed in surgery and sent for pathology processing to assess the margins, a process that takes at minimum several hours, and generally days. If the margins are not clear of tumor, the patient must undergo a second surgery to remove residual tumor. This re-excision rate varies by institution, but can be as high as 60%. Currently, no intraoperative microscopic technique is used routinely to examine tumor margins in breast tissue. A new technique for rapidly scanning large areas of tissue has been developed, called confocal strip scanning, which provides high resolution and seamless mosaics over large areas of intact tissue, with nuclear and cellular resolution and optical sectioning of about 2 microns. Up to 3.5 x 3.5 cm 2 of tissue is imaged in 13 minutes at current stage speeds. This technique is demonstrated in freshly excised breast tissue, using a mobile confocal microscope stationed in our pathology laboratory. Twenty-five lumpectomy and mastectomy cases were used as a testing ground for reflectance and fluorescence contrast modes, resolution requirements and tissue fixturing configurations. It was concluded that fluorescent imaging provides the needed contrast to distinguish ducts and lobules from surrounding stromal tissue. Therefore the system was configured with 488 nm illumination, with acridine orange fluorescent dye for nuclear contrast, with the aim of building an image library of malignant and benign breast pathologies.