cssi/SciSciGPT-SciSciNet huggingface dataset:
Broadband absorption spectroscopy in tissue: combining dual-slope continuous-wave and self-calibrating frequency-domain measurements

One of the chief applications of diffuse optical spectroscopy is the measurement of chromophore concentrations in biological tissue, which requires measurements of tissue absorption. To achieve absolute absorption measurements, two chief confounds must be accounted for: instrumental contributions and tissue scattering. To account for instrumental contributions, a preliminary calibration on a phantom of known optical properties is typically done. The need for a calibration is eliminated by self-calibrating or dual-slope techniques using specially designed probe geometries. A technique that is capable of measuring tissue scattering is frequency domain near-infrared spectroscopy. However, it is typically not implemented for a spectrum of wavelengths due to instrumental complexity. Here we present a technique that combines self-calibrating frequency-domain at two wavelengths, to account for tissue scattering, and dual-slope continuous-wave broadband diffuse reflectance spectroscopy to achieve spectral measurements of absolute absorption between 600 nm and 1064 nm without any need for calibration. We apply this technique to two human tissues in vivo to determine concentrations of oxy-hemoglobin, deoxy-hemoglobin, lipids, and water. We found that the quality of the spectral fits may be significantly improved by the inclusion of a wavelength-independent background absorption. This leads to a discussion on the origin of this background absorption, and on the meaning of the chromophore concentrations that are recovered from spectral analysis. Current work is seeking to further understand and possibly correct for this apparent background absorption.
Increasing hemoglobin concentration with an artificial oxygen carrier improves severe anemia-induced degraded cognitive function

ABSTRACT Before death, patients commonly experience impaired consciousness for a significant period, frequently preventing family and others from final interactions with the patient. Some of these episodes of cognitive impairment may be treatable, with treatment not offered owing to the perception of ultimate futility or expense, or both. One of the causes of terminal loss of consciousness or decreased lucidity can be inadequate cerebral oxygen delivery. We report five cases from four institutions where an infusion of a hemoglobin-based oxygen carrier to patients who were unconscious or not lucid owing to acute severe anemia (hemoglobin range, 2.1-5.2 g/dL) resulted in awakening or lucidity. We review briefly human cognitive function and anemia and remark about the use of a hemoglobin-based oxygen carrier for acute severe anemia when red cell transfusion is not an option.
Surface energy and relaxation in boron carbide (101̄1) from first principles

Abstract The surface energy of the boron carbide polytype B11Cp(CBC) for planar separations along {1011} was determined to be 3.21 J/m2 via first-principles density-functional computations. Surface atomic relaxations are relatively large, thereby lowering the surface energy significantly. The icosahedra are not intact on the surface, i.e., severed polyhedra are the lowest energy surface configuration. Good agreement was found with an experimental average fracture surface energy.
Particle Acceleration in Shell Supernova Remnants: Observational Evidence

The origin of Galactic cosmic-ray electrons and ions up to energies of order a few thousand TeV (the knee in the cosmic-ray spectrum) is generally attributed to shell supernova remnants (SNRs). Until recently, the only direct observational evidence for this conclusion was the presence in SNRs of synchrotron radio emission, indicating electrons with a power-law energy distribution between roughly 0.1 and 100 GeV (in the best cases). Further arguments are necessary to rule out the possibility that these electrons are just borrowed from the ambient Galactic pool and compressed in the remnant shock wave. In the last few years, however, striking evidence at much higher photon energies has emerged: X-ray synchrotron emission in several objects, indicating electrons with energies up to 100 TeV, and TeV photon emission in a few, most likely due to inverse-Compton upscattering of cosmic microwave background photons by these same electrons. Evidence for cosmic-ray ions is so far inconclusive; the most unmistakable form would be detecting the expected bump at a few hundred MeV due to photons from the decay of neutral pions produced in inelastic collisions between cosmic-ray ions and interstellar gas. I shall review these various lines of evidence, and the constraints they impose on theoretical models.
Efficiently representing the radiosity kernel through learning

A novel method for approximating the radiosity kernel by a discrete set of basis functions is presented. The algorithm is characterized by selecting samples from the geometry definition and iteratively creates a functional model instantiated by a set of Gaussian basis functions. These are supported over the whole environment and thus, surfaces are not considered separately. Together with the implicit clustering algorithm provided by the applied learning scheme, the algorithm accounts ideally for coherence in the global kernel function.
Intracellular trafficking of cell surface sialoglycoconjugates

Recent reports have suggested that the majority of the molecular traffic through the Golgi apparatus is comprised of recycling, rather than newly synthesized, molecules. To evaluate the importance of this recycling pathway in greater detail, we examined the internalization and recycling of cell surface glycoproteins on EL-4 cells, a murine T-cell lymphoma, using sialic acids as covalent markers. Sialic acids were removed from the surface of living cells by exhaustive treatment with Vibrio cholerae sialidase at 4 degrees C and shown to be derived primarily from glycoproteins (93%), with only a small amount from glycolipids (7%). Cells were recultured at 37 degrees C over time and monitored for the resialylation of the cell surface using a sensitive high pressure liquid chromatography adaptation of the thiobarbituric acid assay for sialic acids. The return of sialic acid to the cell surface was found to be contingent upon de novo protein synthesis indicating that the bulk of plasma membrane sialoglycoconjugates do not recycle to an endogenous sialyltransferase-containing compartment for oligosaccharide reprocessing. Identical results were found for K562 cells, a human erythroleukemia cell line. The movement of specific glycoproteins was followed using the enzyme rat liver alpha 2-6Gal beta 1-4GlcNAc sialyltransferase together with CMP-[3H]NeuAc as an impermeant probe of the cell surface. Surface sialoglycoproteins were internalized slowly, a process unaffected by cycloheximide treatment. Only a few of these internalized glycoproteins were found to return to a trans-Golgi compartment followed by recycling to the cell surface. Taken together, these data indicate that the majority of replacement of sialic acids on the cell surface is due to de novo synthesis of glycoproteins and that only a small number of glycoproteins recycle through a trans-Golgi compartment.
Endothelium-Dependent and -Independent Vasodilation in Women at Risk of Hypertension

Women with uterine fibroids (UF), benign tumors of the myometrium, have a greater prevalence of hypertension than women without UF. The mechanism of this predisposition is unclear. Individuals with...
Influence of CO(2)-HCO(3) Levels and pH on Growth, Succinate Production, and Enzyme Activities of Anaerobiospirillum succiniciproducens.

Growth and succinate versus lactate production from glucose by Anaerobiospirillum succiniciproducens was regulated by the level of available carbon dioxide and culture pH. At pH 7.2, the generation time was almost doubled and extensive amounts of lactate were formed in comparison with growth at pH 6.2. The succinate yield and the yield of ATP per mole of glucose were significantly enhanced under excess-CO2-HCO3− growth conditions and suggest that there exists a threshold level of CO2 for enhanced succinate production in A. succiniciproducens. Glucose was metabolized via the Embden-Meyerhof-Parnas route, and phosphoenolpyruvate carboxykinase levels increased while lactate dehydrogenase and alcohol dehydrogenase levels decreased under excess-CO2-HCO3− growth conditions. Kinetic analysis of succinate and lactate formation in continuous culture indicated that the growth rate-linked production rate coefficient (K) cells was much higher for succinate (7.2 versus 1.0 g/g of cells per h) while the non-growth-rate-related formation rate coefficient (K′) was higher for lactate (1.1 versus 0.3 g/g of cells per h). The data indicate that A. succiniciproducens, unlike other succinate-producing anaerobes which also form propionate, can grow rapidly and form high final yields of succinate at pH 6.2 and with excess CO2-HCO3− as a consequence of regulating electron sink metabolism.
PERSISTENT SHEDDING OF WEST NILE VIRUS IN URINE OF EXPERIMENTALLY INFECTED HAMSTERS

Adult hamsters that survived experimental West Nile virus (WNV) infection developed persistent viruria. Infectious WNV could be cultured from their urine for up to 52 days. Immunohistochemical examination of kidneys of viruric animals showed foci of WNV antigen in renal tubular epithelial and vascular endothelial cells. These findings are compatible with virus replication and persistent infection of renal epithelial cells. The potential clinical and virologic significance of these findings as well as their possible epidemiologic importance are discussed.
Methods for the detection of paxillin post-translational modifications and interacting proteins by mass spectrometry.

Methods for the simultaneous identification of interacting proteins and post-translational modifications of the focal adhesion adapter protein, paxillin, are presented. The strategy includes (1) lower-level, transient transfection of FLAG-GFP-Paxillin into HEK293 cells, (2) incubation of cells with phosphatase inhibitors prior to lysis, (3) purification of paxillin by anti-FLAG immunoprecipitation, (4) analysis of peptides generated from on-beads digestion using LTQ−FT or LTQ−ETD mass spectrometry, and (5) enrichment of phosphopeptide methyl esters with IMAC. Using the above strategies, we identify 29 phosphorylation sites (19 novel and 10 previously reported) and a novel glycosylation site on Ser 74. Furthermore, with this method, we simultaneously detect 10 co-purifying proteins which are present in focal adhesion complexes. Extension of these methods to other substrates should facilitate generation of global phosphorylation maps and protein−protein interactions for any protein of interest. Keywords: pa...
Sensitivity enhancement of electrospray ionization-MS for aqueous solutions in the corona-assisted cone-jet mode

Abstract An experimental study is reported of the sensitivity obtained for the electrospray ionization of aqueous solutions in two different cone-jet modes. Six different polypeptides varying in molecular weight from ~600 to ~ 12 000 Da were analyzed using a quadrupole mass spectrometer. The sensitivity comparison suggests that more than an order of magnitude enhancement in signal intensity can be achieved in some cases by simply shifting the electrospray operation from the classic cone-jet mode to the corona-assisted cone-jet mode. The sensitivity enhancement in the corona mode spray appears to be independent of both liquid flow rate and sample molecular weight, suggesting that droplet field charging by the corona discharge is the dominant process. Comparison at the field charging limit and the Rayleigh limit indicates that the droplet charge can be effectively increased to the field charging limit for corona mode electrosprays of aqueous solutions at low flow rate.
Embryo development rates after transfer of oocytes matured in vivo, in vitro, or within oviducts of mares.

Objectives of the present study were to use oocyte transfer: 1) to compare the developmental ability of oocytes collected from ovaries of live mares with those collected from slaughterhouse ovaries; and 2) to compare the viability of oocytes matured in vivo, in vitro, or within the oviduct. Oocytes were collected by transvaginal, ultrasound-guided follicular aspiration (TVA) from live mares or from slicing slaughterhouse ovaries. Four groups of oocytes were transferred into the oviducts of recipients that were inseminated: 1) oocytes matured in vivo and collected by TVA from preovulatory follicles of estrous mares 32 to 36 h after administration of hCG; 2) immature oocytes collected from diestrous mares between 5 and 10 d after aspiration/ovulation by TVA and matured in vitro for 36 to 38 h; 3) immature oocytes collected from diestrous mares between 5 and 10 d after aspiration/ovulation by TVA and transferred into a recipient's oviduct 0.1) embryo development rates after the transfer of immature oocytes.
Generation of stable retrovirus packaging cell lines after transduction with herpes simplex virus hybrid amplicon vectors.

Background A number of properties have relegated the use of Moloney murine leukemia virus (Mo-MLV)-based retrovirus vectors primarily to ex vivo protocols. Direct implantation of retrovirus producer cells can bypass some of the limitations, and in situ vector production may result in a large number of gene transfer events. However, the fibroblast nature of most retrovirus packaging cells does not provide for an effective distribution of vector producing foci in vivo, especially in the brain. Effective development of new retrovirus producer cells with enhanced biologic properties may require the testing of a large number of different cell types, and a quick and efficient method to generate them is needed. Methods Moloney murine leukemia virus (Mo-MLV) gag-pol and env genes and retrovirus vector sequences carrying lacZ were cloned into different minimal HSV/AAV hybrid amplicons. Helper virus-free amplicon vectors were used to co-infect glioma cells in culture. Titers and stability of retrovirus vector production were assessed. Results Simultaneous infection of two glioma lines, Gli-36 (human) and J3T (dog), with both types of amplicon vectors, generated stable packaging populations that produced retrovirus titers of 0.5–1.2×105 and 3.1–7.1×103 tu/ml, respectively. Alternatively, when cells were first infected with retrovirus vectors followed by infection with HyRMOVAmpho amplicon vector, stable retrovirus packaging populations were obtained from Gli-36 and J3T cells producing retrovirus titers comparable to those obtained with a traditional retrovirus packaging cell line, ΨCRIPlacZ. Conclusions This amplicon vector system should facilitate generation of new types of retrovirus producer cells. Conversion of cells with migratory or tumor/tissue homing properties could result in expansion of the spatial distribution or targeting capacity, respectively, of gene delivery by retrovirus vectors in vivo. Copyright © 2002 John Wiley & Sons, Ltd.
Source origin of a 50-msec latency auditory evoked field component in young schizophrenic men.

Abstract We recorded auditory evoked magnetic fields in response to 128 15-msec duration 1-KHz tone pips from both hemispheres of 6 young schizophrenic men. Auditory evoked potentials were recorded conventionally from a vertex lead. The approximately 50-msec latency component was identified in both the magnetic (M50) and electroencephalographic (EEG) (P50) recordings. Isofield topographical contour maps were used to estimate A50 source location and depth. Magnetic resonance imaging was used to identify the neuroanatomical structure(s) present at the estimated source location. M50 sources appeared to reside in the planum temporale in both left and right hemispheres in all subjects. Normal interhemispheric asymmetry (with respect to external bony landmarks) of the M50 source was not found in this patient group. Additionally, left (but not right) hemisphere source anatomy differed in several respects from data previously reported in normals.
The Development of Thermals from Rest

Abstract Conventional techniques for releasing a thermal in laboratory experiments induce enough initial motion to affect seriously the thermal's subsequent evolution. We have invented a mechanism for releasing thermals from very close to a state of rest. This allows the examination of the transient behavior of thermals previous to the development of self-similarity. A thermal starting from rest exhibits a much smaller entrainment rate than a self-similar thermal for a distance from its starting point of at least six initial diameters. Since we find that thermals typically penetrate four initial diameters or less in a stably stratified environment, this has potentially great significance for atmospheric convection. Numerical simulations using an axisymmetric, two fluid model aid in the interpretation of these results.
Signal processing using cellular neural networks

The cellular neural network (CNN) architecture combines the best features from traditional fully-connected analog neural networks and digital cellular automata. The network can rapidly process continuous-valued (gray-scale) input signals (such as images) and perform many computation functions which traditionally were implemented in digital form. Here, we briefly introduce the the theory of CNN circuits, provide some examples of CNN applications to image processing, and discuss work toward a CNN implementation in custom CMOS VLSI. The role of analog computer-aided design (CAD) will be briefly presented as it relates to analog neural network implementation.
Organization Science, Managers, and Language Games

This paper examines the relationship between organization science and managerial practice. Science and practice are viewed as interdependent, yet semiautonomous, domains which engage in their own specialized forms of discourse or "language games." The paper examines both the internal dynamics of these language games and the relationship between them. The analysis suggests a reinterpretation of the role played by organizational scientists in relation to practitioners. Organizational scientists should be viewed not as engineers offering technical advice to managers but as providers of conceptual and symbolic language for use in organizational discourse. This view's implications for enhancing the relationship between organization science and managerial practice is discussed.
A free-space method for measurement of dielectric constants and loss tangents at microwave frequencies

For measurements of dielectric properties of planar slabs of ceramic and composite materials, the authors have developed a free-space measurement system in the frequency range of 14.5-17.5 GHz. The key components of the measurement system are a pair of spot-focusing horn lens antennas, a network analyzer, and a computer. Because of the far-field focusing ability of horn lens antennas, the free-space measurements can be made at microwave frequencies in a relatively compact and simple measurement setup. The time-domain gating feature of the network analyzer and the thru, reflect, and line calibration technique were used to eliminate the effects of undesirable multiple reflections. The dielectric constants and loss tangents were measured for standard materials such as fused quartz, Teflon, and polyvinylchloride (PVC). Dielectric properties for Teflon and PVC were also measured in a waveguide medium for purposes of comparison with the free-space method. >
GAY AND LESBIAN RIGHTS IN CANADA: A COMPARATIVE STUDY

Canadian gays and lesbians have made tremendous strides in realizing their dream of full equality in Canadian society. The adoption of the Charter of Rights in 1982, recent Supreme Court interpretations of the Charter, and public opinion have all contributed to that progress. This paper looks at the gains Canadian gays and lesbians have made in the policy areas of civil rights, spousal rights and gays in the military. These developments are considered in the context of Canadian constitutional change, as well as Canadian history, society and politics; and it compares the policy struggles of Canadian gays and lesbians with those of gays and lesbians in the United States.
Angiostatic Effects of Aspirin in Hypoxia-Reoxygenation Are Linked to Modulation of TGFβ1 Signaling

Hypoxia-reoxygenation (HR) is a major driver for angiogenesis in atherosclerotic plaques and tumors. Angiogenesis is a multistep process requiring stimulation of proliferation and migration of endothelial cells in response to a number of growth factors, including transforming growth factor (TGFβ1). Aspirin (acetylsalicylic acid) has been shown to reduce atherosclerosis-related events as well as development of certain tumors. We examined the role of aspirin in HR-mediated angiogenesis from human umbilical vein endothelial cells (HUVECs). We found that aspirin (0.5 and 1 mmol/L) markedly (by about 30%, P < .01) reduced HR-mediated tube formation. Next, we studied changes in TGFβ1 and its type 1 receptor (TGFβ-R1) as well as in the transcription of p53 and p21 during HR-mediated angiogenesis. Hypoxia-reoxygenation modestly increased TGFβ1 and decreased its type 1 receptor (TGFβ-R1) transcription (both P-NS) and reduced the transcription of p53 and p21 (P < .05). Treatment of HUVECs with aspirin suppressed TGFβ1 and enhanced TGFβ-R1 mRNA expression during HR (both P < .05 vs HR alone) without a change in p53 and p21 (P-NS). In other experiments, treatment of cells with TGFβ1 antibody modestly decreased HR-mediated angiogenesis; however, TGFβ1 antibody treatment significantly enhanced the inhibitory effect of aspirin on tube formation. Based on these data, we suggest that the inhibitory effect of aspirin on HR-mediated angiogenesis involves TGFβ1-TGFβ-R1 pathway.
Treatment of Volatile Organic Chemicals on the EPA Contaminant Candidate List Using Ozonation and the O3/H2O2 Advanced Oxidation Process

Seven volatile organic chemicals (VOCs) on the EPA Contaminant Candidate List together with 1,1-dichloropropane were studied for their reaction kinetics and mechanisms with ozone and OH radicals during ozonation and the ozone/hydrogen peroxide advanced oxidation process (O3/H2O2 AOP) using batch reactors. The three aromatic VOCs demonstrated high reactivity during ozonation and were eliminated within minutes after ozone addition. The high reactivity is attributed to their fast, indirect OH radical reactions with kOH,M of (5.3−6.6) × 109 M-1 s-1. Rates of aromatic VOC degradation are in the order 1,2,4-trimethylbenzene > p-cymene > bromobenzene. This order is caused by the selectivity of the direct ozone reactions (kO3,M ranges from 0.16 to 304 M-1 s-1) and appears to be related to the electron-donating or -withdrawing ability of the substituent groups on the aromatic ring. The removal rates for the five aliphatic VOCs are much lower and are in the order 1,1-dichloropropane > 1,3-dichloropropane > 1,1-dich...
Functional optical coherence tomography reveals transient phototropic change of photoreceptor outer segments

Dynamic near infrared microscopy has revealed transient retinal phototropism (TRP) correlated with oblique light stimulation. Here, by developing a hybrid confocal microscopy and optical coherence tomography (OCT), we tested sub-cellular source of the TRP in living frog retina. Dynamic confocal microscopy and OCT consistently revealed photoreceptor outer segments as the anatomic source of the TRP. Further investigation of the TRP can provide insights in better understanding of Stiles–Crawford effect (SCE) on rod and cone systems, and may also promise an intrinsic biomarker for early detection of eye diseases that can produce photoreceptor dysfunction.
Ragweed hay fever: treatment by local passive administration of IgG antibody.

Summary To determine whether the local administration of IgG antibodies might reduce the symptoms of ragweed hay fever, we tested the effect of this treatment in fourteen patients in a double-blind pilot trial. The patients were randomly divided into two groups, treatment and placebo, and their symptoms and medication usage were determined during the ragweed pollination season. One group used a nasal spray consisting of phosphate-buffered saline (PBS) containing human serum albumin, whereas the other used PBS containing purified IgG from a subject with a high titre of IgG antibody to partially purified ragweed antigen E. Treated and control groups used comparable quantities of nasal spray, and neither noted any ill effects. Comparison of individual symptoms of hay fever, medication usage, and total symptom scores showed no significant differences between the groups except a lessening of eye symptoms (P<0.05) in the treated group. The results suggest that nasal administration of IgG antibody up to five times daily does not alter the severity of symptoms in ragweed hay fever. Furthermore, total serum IgE protein and specific IgE levels increased comparably in both groups, suggesting that passive administration of IgG antibody does not suppress the production of IgE antibody during the pollination season.
DOE's support of the Sloan Digital Sky Survey.

The U.S. Department of Energy (DOE) rarely gets the credit it deserves for its science programs, and in the case of the Sloan Digital Sky Survey, it deserves a lot of credit. The contributions to the project from Fermilab and Los Alamos National Laboratory that Ann Finkbeiner discusses in her
Elevated GM-CSF and IL-1β levels compromise the ability of p38 MAPK inhibitors to modulate TNFα levels in the human monocytic/macrophage U937 cell line

Rheumatoid arthritis (RA) is a complex, multicellular disease involving a delicate balance between both pro- and anti-inflammatory cytokines which ultimately determines the disease phenotype. The simultaneous presence of multiple signaling molecules, and more specifically their relative levels, potentially influences the efficacy of directed therapies. Using the human U937 monocytic cell line, we generated a self-consistent dataset measuring 50 cytokines and 23 phosphoproteins in the presence of 6 small molecule inhibitors under 15 stimulatory conditions throughout a 24 hour time course. From this dataset, we are able to explore phosphoprotein and cytokine relationships, as well as evaluate the significance of cellular context on the ability of small molecule inhibitors to block inflammatory processes. We show that the ability of a p38 inhibitor to attenuate TNFα production is influenced by local levels of GM-CSF and IL-1β, two cytokines known to be elevated in the joints of RA patients. Within the cell, compensatory mechanisms between signaling pathways are apparent, as selective p38 MAPK inhibition results in the increased phosphorylation of other MAPKs (ERK and JNK) and their downstream substrates (CREB, c-Jun, and ATF-2). Further, we demonstrate that TNFα-neutralizing antibodies have secondary effects on cytokine production, impacting more than just TNFα alone. p38 MAPK inhibition using a small molecule inhibitor also blocks production of anti-inflammatory cytokines including IL-10, IL-1ra and IL-2ra. Collectively, the impact of cell context on TNFα production and unintended blockade of anti-inflammatory cytokines may compromise the efficacy of p38 inhibitors in a clinical setting. The effort described in this work evaluates the effect of inhibitors on multiple endpoints (both intra- and extracellular), under a range of biologically relevant conditions, thus providing a unique means for differentiation of compounds and potential opportunity for improved pharmacological manipulation of disease endpoints in RA.
Enzymes of l-(+)-3-hydroxybutyrate metabolism in the rat☆

Abstract The three enzymes required for the production and utilization of l -(+)-3-hydroxybutyrate were sought in various tissues of the rat. All tissues examined contained substantial amounts of (No. 1) l -(+)-3-hydroxybutyryl CoA dehydrogenase (EC 1.1.1.35). The specific activity of (No. 2) l -(+)-3-hydroxybutyryl CoA deacylase (EC 3.1.2) was highest in liver (3.8 mU/mg in mitochondrial matrix (1 U = 1 μmol/min). Brain, heart, and skeletal muscle contained l -(+)-3-hydroxybutyrate CoA, while Peak II activity was highest using l -(+)-3-hydroxybutyryl CoA. The Km(app) for Peak II deacylase with l -(+)-3-hydroxybutyryl CoA was 19 μ m . Acyl CoA synthetase (EC 6.2.1.2) (No. 3) was assayed with sorbate (sorboyl CoA ligase) or l -(+)-3-hydroxybutyrate ( l -(+)-3-hydroxybutyryl CoA ligase). The highest specific activity for l -(+)-3-hydroxybutyryl CoA ligase was associated with brain mitochondria (8.3 mU/mg). In the “matrix” fraction of rat liver mitochondria the activities of these two acyl CoA synthetases were distinguished chromatographically and by their stability at various pH values. Heart and skeletal muscle mitochondria contained l -(+)-3-hydroxybutyrate production.
Persistent cervical adenitis and nasopharyngeal carcinoma in children

The high prevalence of inflammatory disease in pediatric patients makes the occurrence of prominent adenoidal tissue and cervical adenopathy a common finding. Unfortunately, rare nasopharyngeal cancer shares these physical findings in common with benign inflammatory disease of the pharynx. Computed tomography permits evaluation of nodal necrosis or wall nodularity, allowing clinically silent submucosal tumor extension to be well defined. In patients with suspected nasopharyngeal inflammatory disease who do not respond to conservative therapy, computed tomography can be used to aid directed biopsies.
Factors Influencing Willingness-to-Pay for the Energy Star Label

Abstract In the United States, nearly 17% of greenhouse gas emissions come from residential energy use. Increases in energy efficiency for the residential sector can generate significant energy savings and emissions reductions. Consumer labels, such as the US Environmental Protection Agency's ENERGY STAR, promote conservation by providing consumers with information on energy usage for household appliances. This study examines how the ENERGY STAR label affects consumer preferences for refrigerators. The results of an online survey of a national sample of adults suggest that consumers are, on average, willing to pay an extra $249.82–$349.30 for a refrigerator that has been awarded the ENERGY STAR label. Furthermore, the results provide evidence that respondent willingness-to-pay was motivated by both private (energy cost savings) and public (environmental) benefits.
Compositional topography of melon and spermaceti organ lipids in the pygmy sperm whale Kogia breviceps: Implications for echolocation

The forehead of the pygmy sperm whale Kogia breviceps contains a large “melon” of fatty tissue in front of a small, fat-filled, cornucopia-shaped spermaceti organ. This unique anatomical structure may possibly play an acoustical role in the whale's echolocation system, similar to the fatty “melon” sound lens postulated for dolphins. To better understand its function, we have studied the compositional topography of the K. breviceps melon and spermaceti organ lipids. The fatty head tissues of an adult K. breviceps were serially sectioned into 9 transverse slices. Appropriate tissue samples were cut from every other slice, and analyzed for % lipid and lipid class composition. Wax esters and triglycerides were the only major lipids present; their average carbon number in each sample was determined by gas-liquid chromatography (GLC). Our topographical analyses of K. breviceps melon indicate 3 regions of distinctive lipid composition: a fat-poor melon exterior, an “outer melon” of medium fat content having % triglyceride>% wax ester, and a fat-rich “inner melon” having % wax ester>% triclyceride. The spermaceti organ contains a fat-rich core of very high wax-ester content (84 to 99%), surrounded by a fat-poor case. Average carbon numbers of both wax esters and triglycerides were lowest in the inner melon and the spermaceti organ. At the rear of the spermaceti organ lies the “museau de singe”, an apparent sound generator. The lipid topography data plus anatomical and acoustical considerations suggest that the K. breviceps melon/spermaceti organ system may function as an acoustical transducer, directing and refracting sound waves from this source for the purpose of echolocation.
Multifactorial analysis of acetaldehyde kinetics during alcoholic fermentation by Saccharomyces cerevisiae

Abstract Acetaldehyde is the terminal electron acceptor in the alcoholic fermentation by Saccharomyces cerevisiae . Quantitatively the most important carbonyl by-product, it has relevance for ethanol production yields as well as product stabilization and toxicology. The aim of this study was to investigate the effect of various enological parameters on acetaldehyde kinetics during alcoholic fermentations. Two commercial yeast strains were tested in two grape musts and the pH, temperature, SO 2 and nutrient addition were varied. All incubations had uniform kinetics where acetaldehyde reached an initial peak value followed by partial reutilization. Peak acetaldehyde concentrations and residual concentrations after 15 days of fermentations ranged from 62 to 119 mg l − 1 and 22 to 49 mg l − 1 , respectively. A positive linear relationship was found between peak and final acetaldehyde levels in Gewurztraminer, but not Sauvignon Blanc fermentations, where sluggish fermentations were observed. Several factors had a significant effect on peak and/or final acetaldehyde levels. SO 2 addition, grape cultivar and fermentation nutrition were important regulators of peak acetaldehyde production, while final acetaldehyde concentrations were correlated with SO 2 addition, grape cultivar and temperature. The results allowed to estimate the acetaldehyde increase caused by SO 2 addition to 366 μg of acetaldehyde per mg of SO 2 added to the must. The course of the final fermentation phase was shown to determine acetaldehyde residues. Comparison of acetaldehyde and hexose kinetics revealed a possible relationship between the time of occurrence of peak acetaldehyde concentrations and the divergence of glucose and fructose degradation rates.
Climate of Brazil's nordeste and tropical atlantic sector: preferred time scales of variability

Resuming earlier research, this study explores rainfall variability in Brazil's Nordeste and underlying circulation mechanisms. The semi-arid northern Nordeste has its short rainy season centered around March-April-May, when temperature maximum, low pressure trough and wind confluence reach their southernmost position. Interannual variability can be understood as departures from the average annual cycle. Based on novel long-term datasets, the present study explores the preferred time scales of variability. In Nordeste rainfall and pertinent circulation indices in the tropical Atlantic sector most prominent are frequencies of 13.2, 9.9 and 5.6 years. Frequency peak of 13.1 years appears also in the record of Southern Oscillation, and of 5.6 years in North Atlantic Oscillation, indicative of causality chain.
Effect of Water Potential, Temperature, and Soil Microbial Activity on Release of Starch-Encapsulated Atrazine and Alachlor

Starch encapsulation has been proposed as a method for controlling the rate at which pesticides are released into the soil. Relatively little is known about what environmental factors influence controlled release. A series of laboratory studies were initiated to improve our understanding of how water potential, temperature, and soil microbial activity influence rate of release of starch-encapsulated atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) and alachlor (2-chloro-2',6'-diethyl-N-(methoxymethyl)-acetanilide) (...)
Stretching exercises — flexibility in dihydrofolate reductase catalysis

As an enzyme, dihydrofolate reductase performs two tasks: transformation of its substrate dihydrofolate or folate to tetrahydrofolate, using NADPH as a cofactor, and regeneration of the enzyme for a subsequent round of catalysis. Studies discussed in this review highlight the role of conformational flexibility in both of these enzymatic functions.
Differences in the multiple scattering of positrons and electrons

Abstract After a brief review of differences between the scattering cross sections for electrons and positrons, results are presented on the transmission and reflection of these particles by foils. These results were obtained with the Monte Carlo code ETRAN, which takes into account positron-electron differences of stopping powers and elastic-scattering cross sections. The principal output of the calculations consists of number and energy transmission and reflection coefficients for electrons and positrons. A few results are also shown pertaining to differences of energy spectra and angular distributions of positrons and electrons reflected from thick foils. The calculated transmission coefficients for positrons are greater, and the reflection coefficients smaller, than those for electrons of the same energy. These results are in qualitative agreement with experimental data, but the quantitative agreement is not very close.
Error Estimation in Numerical Inversion of Laplace Transforms Using Padé Approximation

Abstract Uniform asymptotic estimates for the error in the main diagonal and first two subdiagonal Pade approximants for exp(iz) in a sector covering the real z axis are derived. The results are applied to analyze the error in a cerain procedure for the numerical inversion of the Laplace transform.
Layer formation in monodispersive suspensions and colloids

We present theoretical results on spontaneous stratification of sedimenting suspensions and colloids caused by a lateral temperature gradient. Fluid motion is treated in the Stokes approximation, and motion of suspended particles is described by Burgers equation with convection. The internal structure and interaction of shocks at convection roll boundaries is studied numerically using a reduced one-dimensional model based on a Galerkin approach. Qualitative comparison is made to experimental data.
All-Optical Signal Processing

Optical signal processing brings together various fields of optics and signal processing - namely, nonlinear devices and processes, analog and digital signals, and advanced data modulation formats - to achieve high-speed signal processing functions that can potentially operate at the line rate of fiber optic communications. Information can be encoded in amplitude, phase, wavelength, polarization and spatial features of an optical wave to achieve high-capacity transmission. We revisit advances in the key enabling technologies that led to recent research in optical signal processing for digital signals that are encoded in one or more of these dimensions. Various optical nonlinearities and chromatic dispersion have been shown to enable key sub-system applications such as wavelength conversion, multicasting, multiplexing, demultiplexing, and tunable optical delays. We review recent advances in high-speed optical signal processing applications in the areas of equalization, regeneration, flexible signal generation, and optical control information (optical logic and correlation).
Analysis of genetic heterogeneity within the type strain of satellite tobacco mosaic virus reveals several variants and a strong bias for G to A substitution mutations

Abstract Satellite tobacco mosaic virus (STMV) is a small plant virus that is dependent for its replication on the presence of a helper tobamovirus. RNase protection analysis of genomic RNA of the STMV type strain revealed that it was composed of two major genome types which differed at a single detectable site near nucleotide 753. Analyses of 42 full-length STMV clones for sequence heterogeneity resulted in the identification of 16 variants distinguishable by unique RNase protection assay patterns. Characterization of these variants confirmed the presence of a major heterogeneity site at nucleotide 751 and identified several sites of sequence micro heterogeneity typical of an RNA quasispecies population. Mapping of the heterogeneity sites revealed an apparently random distribution along the length of the STMV genome, with no significant clustering or preference for noncoding regions. Infectivity experiments in tobacco showed that RNA transcripts of 13 of the 16 variant clones were infectious, indicating that most of the variants represent functional genomes coexisting in the type strain with the two major genome types. Sequence analyses revealed that most of the heterogeneity sites detected, including the major site of heterogeneity, were single base differences. Assessment of all the heterogeneity sites found in the total of 10,545 nt sequenced allowed us to estimate that the RNase protection assays detected approximately 50% of the differences present in the 16 clones studied. The nature of these differences was highly biased in that 18 of the 29 single base differences characterized (62%) were G to A substitutions.
Molecular properties of Li2+ from model potential calculations

Abstract The constructive model potential approach of Bottcher and Dalgarno is used in the calculation of some molecular properties of two electronic states, 2 Σ g + and 2 Π u , of Li 2 + at several internuclear distances. The results agree well with ab initio calculations.
Implications of epidermal growth factor (EGF) induced egf receptor aggregation.

To investigate the role of receptor aggregation in EGF binding, we construct a mathematical model describing receptor dimerization (and higher levels of aggregation) that permits an analysis of the influence of receptor aggregation on ligand binding. We answer two questions: (a) Can Scatchard plots of EGF binding data be analyzed productively in terms of two noninteracting receptor populations with different affinities if EGF induced receptor aggregation occurs? No. If two affinities characterize aggregated and monomeric EGF receptors, we show that the Scatchard plot should have curvature characteristic of positively cooperative binding, the opposite of that observed. Thus, the interpretation that the high affinity population represents aggregated receptors and the low affinity population nonaggregated receptors is wrong. If the two populations are interpreted without reference to receptor aggregation, an important determinant of Scatchard plot shape is ignored. (b) Can a model for EGF receptor aggregation and EGF binding be consistent with the "negative curvature" (i.e., curvature characteristic of negatively cooperative binding) observed in most Scatchard plots of EGF binding data? Yes. In addition, the restrictions on the model parameters required to obtain negatively curved Scatchard plots provide new information about binding and aggregation. In particular, EGF binding to aggregated receptors must be negatively cooperative, i.e., binding to a receptor in a dimer (or higher oligomer) having one receptor already bound occurs with lower affinity than the initial binding event. A third question we consider is whether the model we present can be used to detect the presence of mechanisms other than receptor aggregation that are contributing to Scatchard plot curvature. For the membrane and cell binding data we analyzed, the best least squares fits of the model to each of the four data sets deviate systematically from the data, indicating that additional factors are also important in shaping the binding curves. Because we have controlled experimentally for many sources of receptor heterogeneity, we have limited the potential explanations for residual Scatchard plot curvature.
Radio-wave-reflecting concrete for lateral guidance in automatic highways

Abstract A method for producing radio-wave-reflecting concrete, which is potentially useful for lateral guidance in automatic highways, is provided. In the form of cement paste, it contains a small amount (0.5 vol.%) of 0.1 μm diameter carbon filaments as an admixture. The radiation absorbed is negligible compared to that reflected. The reflectivity at 1 GHz is 10 dB higher for radio-wave-reflecting cement paste compared to conventional cement paste. With the filaments, the reflectivity is 29 dB higher than the transmissivity. Without the filaments, the reflectivity is 3–11 dB lower than the transmissivity. The addition of the filaments not only provides the ability to reflect electromagnetic radiation, it also reinforces the cement paste under tension, especially if the filaments have been treated with ozone prior to incorporation in the paste.
Thermal Properties of Bacteriorhodopsin

In this Feature Article we review the effects of various parameters on the structure and thermal stability of one of the most widely studied membrane proteins, bacteriorhodopsin. This protein has recently been crystallized and its high-resolution structure elucidated to 1.55 A. This information has proved invaluable in understanding its proton-pumping mechanism. However, the question of why bacteriorhodopsin is so stable over a wide range of conditions, and which factors contribute to this stability, is still largely unanswered. Spectroscopic and calorimetric experiments provide information on the thermodynamics, kinetics and structural changes upon unfolding and refolding the protein under various environmental perturbations. FT-IR spectroscopy has been particularly useful in determining the changes in secondary structure upon heating through its thermal transitions after changing pH and cations, removing and adding lipids and detergents, retinal reduction and removal, and site-directed mutagenesis. Thes...
Persistent Virus Infection Inhibits Type I Interferon Production by Plasmacytoid Dendritic Cells to Facilitate Opportunistic Infections

Emerging studies indicate an association between virus-induced impairment in type I interferon (IFN-I) production and enhanced susceptibility to opportunistic infections, which represent a major health problem. Here, we provide in vivo evidence that lymphocytic choriomeningitis virus (LCMV) infection of its natural murine host dramatically diminishes the unique capacity of plasmacytoid dendritic cells (pDCs) to secrete high levels of systemic IFN-I. While both acute and persistent LCMV infections suppress pDC IFN-I response, only the persistent virus induces a long-lasting diversion of this innate immune pathway. The consequent reduction in IFN-I production serves to impair natural killer cell responses in LCMV-infected mice challenged subsequently with murine cytomegalovirus (MCMV) as an opportunistic pathogen. This innate defect also compromises the host's ability to counteract early MCMV spread. These findings provide a mechanistic explanation for the occurrence of opportunistic infections following viral insults and have important implications for treating such medical complications.
Clarifying the Concept of Representation

This response to Andrew Rehfeld's “Representation Rethought” (American Political Science Review 2009) takes up his criticisms of my “Rethinking Representation” (American Political Science Review 2003) to advance a more relational and systematic approach to representation. To this end, it suggests replacing the “trustee” concept of representation with a “selection model” based on the selection and replacement of “gyroscopic” representatives who are both relatively self-reliant in judgment and relatively nonresponsive to sanctions. It explores as well the interaction between representatives’ (and constituents’) perceptions of reality and their normative views of what the representative ought to represent. Building from the concept of surrogate representation and other features of legislative representation, it argues for investigating, both normatively and empirically, not only the characteristics of individual representatives emphasized by Rehfeld's analysis but also the representative–constituent relationship and the larger representative system, including both elected and nonelected representatives, inside and outside the legislature.