cssi/SciSciGPT-SciSciNet huggingface dataset:
Taking the (southern) waters: science, slavery, and nationalism at the Virginia springs.

‘Taking the (southern) waters’ argues that, in the pre-Civil War period, the space of Virginia's mineral water resorts and the philosophy of southern hydropathic medicine enabled – indeed, fostered – white southerners’ constructions of a ‘nationalist,’ proslavery ideology. In the first half of the paper, the author explains how white southern health-seekers came to view the springs region as a medicinal resource peculiarly designed for the healing of southern diseases and for the restoration of white southern constitutions; in the second half, she shows how physical and social aspects of the resorts, such as architectural choices and political events, supported and encouraged proslavery ideologies. Taken together, these medical-social analyses reveal how elite white southerners in the antebellum period came to associate the health of their peculiarly ‘southern’ bodies with the future health of an independent southern nation, one that elided black bodily presence at the same time that its social structures...
On vortical flow and sound generation

The generation of an acoustic field by an unsteady viscous vortical flow is investigated analytically, with a focus on the case where the reference scale length of the flow is much smaller than that of the acoustic field. The expansion schemes, governing equations, and far-field behavior are described; the effect of pressure and density fluctuations on the next-order far-field solution is explored; and the method of matched asymptotics is applied to construct the leading-order solution of the induced acoustic field. Particular attention is given to the sound generated by turbulence and by slender vortex filaments.
Serotonergic, sensory modifications in the apical ganglion during development to metamorphic competence in larvae of the dendronotid nudibranchs Melibe leonina and Tritonia diomedea

The following investigation examines changes in the distance between the right and left dendritic termini arising from the serotonergic sensory neurons found in the apical ganglion of the larval dendronotid nudibranchs, Melibe leonina and Tritonia diomedea. A significant increase in separation, that is different in extent, occurs in both species as they grow from hatching to metamorphic competence. Competent M. leonina larvae exhibit a separation that is about 4.5 times that at hatching, whereas competent larvae of T. diomedea show an increase that is only 1.6times that at hatching. The increase in separation of the lateral, serotonergic, dendritic termini (particularly in M. leonina) may allow the larva to more effectively assess left versus right differences in an as yet unknown sensory stimulus. The serotonergic innervation that arises from the apical ganglion is known to be associated with the muscles and large ciliated cells of the velum. Better right versus left discrimination of sensory stimuli experienced during the pelagic or settling larval phases may allow the larva to more precisely control swimming activities such that the likelihood of successful feeding or settlement behavior is increased. Microsc. Res. Tech., 2008. © 2008 Wiley-Liss, Inc.
The intramural practice plan in dental education (including a survey of American Dental Schools)

O ne of the gravest concerns of dentistry, and more specifically of dental educa­ tion, has been the continuous shortage of well-trained, full-time teachers in the dental schools of the U nited States. In place of the dentists who would make careers of dental education are large numbers of part-tim e instructors and professors who divide their time between teaching and private practice. D ental education has not been able to compete successfully with the greater financial remunerations of private prac­ tice. Teacher income, in almost all fields, has failed to keep pace w ith the chang­ ing standard of living. T he dental school, as a component of the university family, has suffered in the same m anner as the other schools of the university; and, in some areas, university administrators and state legislatures have determined that dental schools should receive even smaller sums of money because of the be­ lief that the school has a great degree of earning power through its clinical facilities. T he average full-time dental school faculty member who has no outside source of income finds himself in an un ­ enviable financial position. The only so­ lution to the problem is to find some means of raising faculty salaries to levels comparable w ith the income of private practitioners of dentistry. U ntil tha t time comes, other attem pts undoubtedly will be made to provide an additional source of income for the dental faculty mem­ ber. O ne such plan, the “intram ural practice plan,” was discussed at the Twelfth Congress on D ental Education and Licensure on February 4, 1956, in Chicago. Shailer Peterson, secretary of the Council on D ental Education of the American Dental Association, made the opening remarks at the Congress.1 He stated tha t the in tram ural practice plan “has been of m ore than a little concern to the (dental) examiners in several states.” He pointed out tha t the schools which used this plan did so with the in­ tent of “attracting faculty” and “for the purpose of perm itting their faculties to continue to have practice experience.” He mentioned tha t “in two states at least, the dental societies have been consider­ ably concerned about the operation of such programs.” J. Ben Robinson,2 dean of the School of Dentistry of West V irginia University, expressed the belief that, “Even in the face of extreme discouragement, and in
Quantification of contact oviposition stimulants for black swallowtail butterfly, Papilio polyxenes, on the leaf surfaces of wild carrot, Daucus carota

Ovipositing black swallowtail butterflies,Papilio polyxenes, make their final host-selection decisions on the basis of compounds present on the leaf surface. Little information is available, however, on the chemistry of leaf surfaces. The purpose of this study was to develop a technique to extract and quantify the concentrations of compounds from the leaf surfaces ofDaucus carota, one of the main host species forP. polyxenes, with particular reference to compounds already identified as contact oviposition stimulants, namelytrans-chlorogenic acid (CA) and luteolin-7-O-(6″-O-malonyl)-β-D-glucopyranoside (L7MG), as well as its degradation product luteolin-7-glucoside (L7G). Plant surfaces were extracted by dipping leaves sequentially in pairs of solvents: (1) CHCl3-MeOH, (2) near-boiling H2O, (3) CHCl3-near-boiling H2O, and (4) CH2Cl2-CH2Cl2. The resulting extracts were fractionated and analyzed using high-performance liquid chromatography. The leaf-surface concentrations of each compound were calculated using regressions relating leaf surface area to leaf weight that were obtained from measurements of field-collected carrot plants. All four methods removed the three compounds from carrot leaf surfaces, but the solvent systems differed in effectiveness. The chloroform-near-boiling water solvent system performed better than the other solvent combinations, but not significantly so. This system also extracted the highest number of polar, UV-absorbing compounds. Methylene chloride was significantly less efficient than the other methods. An additional test confirmed that the chloroform-near-boiling water method removed compounds from the surface alone and probably not from the apoplast or symplast. Surface concentrations of CA (up to 600 ng/cm(2) leaf surface) were substantially greater than those of the two flavonoid compounds. No clear seasonal trend in concentrations was evident from the limited number of sampling dates.
Mechanochemistry: One Bond at a Time

Single-molecule force-clamp spectroscopy offers a novel platform for mechanically denaturing proteins by applying a constant force to a polyprotein. A powerful emerging application of the technique is that, by introducing a disulfide bond in each protein module, the chemical kinetics of disulfide bond cleavage under different stretching forces can be probed at the single-bond level. Even at forces much lower than that which can rupture the chemical bond, the breaking of the S-S bond at the presence of various chemical reducing agents is significantly accelerated. Our previous work demonstrated that the rate of thiol/disulfide exchange reaction is force-dependent and well-described by an Arrhenius term of the form r = A(exp((FΔx(r) - E(a))/k(B)T)[nucleophile]). From Arrhenius fits to the force dependency of the reduction rate, we measured the bond elongation parameter, Δx(r), along the reaction coordinate to the transition state of the S(N)2 reaction cleaved by different nucleophiles and enzymes, never before observed by any other technique. For S-S cleavage by various reducing agents, obtaining the Δx(r) value can help depicting the energy landscapes and elucidating the mechanisms of the reactions at the single-molecule level. Small nucleophiles, such as 1,4-dl-dithiothreitol (DTT), tris(2-carboxyethyl)phosphine (TCEP), and l-cysteine, react with the S-S bond with monotonically increasing rates under the applied force, while thioredoxin enzymes exhibit both stretching-favored and -resistant reaction-rate regimes. These measurements demonstrate the power of the single-molecule force-clamp spectroscopy approach in providing unprecedented access to chemical reactions.
Mechanoreceptors and autonomic responses to movement in humans

Mechanoreceptor contribution to efferent autonomic outflow is incompletely understood. To determine the effects of mechanorceptor stimulation on autonomic reflexes, we compared autonomic responses in 34 subjects using a cross-over, counterbalanced design, in which hemodynamic, electromyographic, metabolic, and autonomic data were gathered during rest, passive, and active movement protocols. Because metaboreceptors and ventilatory responses influence autonomic outflow we verified and controlled for these influences during all protocols through comparisons of breath-by-breath gas exchange measurements. Verification of active and passive movements was made via electromyographic recordings of the moving legs. Spectral analysis of R-R variability was used to assess autonomic activity, and low to high frequency ratios were considered representative of sympathovagal balance. A repeated measures analysis of variance revealed significant modulating effects of mechanoreceptor stimulation on sympathovagal balance during passive movement upon efferent autonomic outflow (p<0.01) independent of central command, chemoreceptor, and metaboreceptor stimulation. Furthermore, breathing frequency and volume were identical for both movement protocols. Therefore, findings in this investigation suggest that modulating influences are being exerted by mechanoreceptor stimulation on autonomic outflow to the heart.
Gas phase reaction rates of C+ with O2, NO and N2O near 0.6 K

Abstract We report the measurement of absolute ion-molecule rate constants, obtained using a novel free jet expansion flow reactor, at translational temperatures near 0.6 K. The reactions of C + with O 2 , NO and N 2 O have been studied. All three reactions are found to have rate constants significantly greater than those observed at 300 K. The observed rate constants for reaction with NO and N 2 O can be explained upon consideration of the ion-dipole interaction. Using the assumed temperature of 0.6 K, the very fast reaction of C + with O 2 cannot be explained with current capture theories which account for ion-quadrupole interaction.
Variational principle for global stability of elasto-plastic thin shells

This chapter will investigate the nonlinear postcritical asymmetric behavior of thin elasto-plastic shells under a static load, by applying the geometric method. Usually, the experimental data for asymmetrically deformed shells shows that plastic zones first appear in the neighborhood of the deformation ribs \( \widetilde\gamma \in {\rm Z} \). In Section 3.2 we introduce some assumptions about the distribution of the postcritical elasto-plastic deformation energy, defined on the isometric transformation Z. We thus first derive the asymptotic expression for the energy of postcritical deformations of thin elasto-plastic shells. In Section 3.3 we formulate an analogue of Pogorelov’s variational principle A, extended to elasto-plastic shells. With the aid of asymptotic analysis of nonlinear partial differential equations for shallow elasto-plastic shells we shall prove the existence of isometric transformation. The first asymptotic approximation of isometric transformation is a non-trivial solution of Monge-Amper’s equation. Following the second asymptotic iteration of the corresponding partial differential equations we obtain the ordinary differential equations for the functions regularizing the solution. These functions are related to one of the basic assumptions of the geometric method, which makes the introduction of “rib-smoothing” deformation possible. Thus, the assumptions of the geometric method will be confirmed, while the asymptotic accuracy of the postcritical deformation energy and of the functions regularizing the surface Z will be evaluated. The postcritical deformations of thin elasto-plastic cylindrical shells under axial compression will be studied in Section 3.4 with the aid of the extended variational principle A. We will obtain the curve of the load as a decreasing function of the postcritical deformation parameter at a constant elastic yield limit.
Studio-based learning in interprofessional education

The recent growth of interprofessional education (IPE) in healthcare has been accompanied by exploration of teaching strategies to improve its effectiveness. Experts in IPE advise faculty to explore teaching models from other disciplines outside of healthcare. Studio-based learning (SBL) in design education embodies many of the features that are integral to effective IPE. Students work in teams to design new processes and products to solve complex and real-life problems. The purpose of this paper is to describe features of SBL that enhance IPE and examine student experiences of interprofessional learning from three healthcare design studios. Findings from an exploratory case study of these design studios involving students from a range of professions suggest that the students transition through learning stages in SBL that may enhance IPE. The paper goes on to discuss the unique features of SBL and how they offer new and complementary strategies for building interprofessional curricula.
Diminished drug metabolism due to hormonal effects of cobalt mesoporphyrin on flavoproteins.

Abstract Substituted metalloporphyrins, in addition to their use as pharmacological agents, are used to investigate metabolic pathways by inhibiting cytochrome P-450. We have examined the specificity of this approach with cobalt mesoporphyrin (CoMP). In vivo, CoMP (50 μmol/kg, s.c.) decreased rat hepatic microsomal cytochrome P-450, NADPH cytochrome P-450 reductase, benzphetamine N-demethylase (BZPH) activity, and thyroid hormones by >50%, all of which returned to control levels after 45 days; testosterone levels were also reduced at this dose. The half-life of CoMP was 18 days, which is consistent with this sustained effect. At 10 μmol/kg of CoMP, the reductase activity was decreased, but cytochrome P-450 was unchanged. An effect of residual CoMP on the reductase was ruled out as the CoMP content of tissue fractions was not high enough to inhibit directly the reductase activity (even after 50 μmol CoMP/kg). However, immunoblots indicated a lower level of immunoreactive reductase protein following treatment. After 8 weekly doses of 1 μmol CoMP/kg, BZPH activity was 39% less than control but neither P-450 content nor reductase activity was significantly changed. The P-450 content and reductase activity in rabbits were much less affected by CoMP, perhaps due to differences in the disposition of CoMP. Thyroidectomy decreased reductase activity in rats to an extent that was seen with CoMP at 50 μmol/kg; CoMP treatment of thyroidectomised rats did not further decrease reductase activity. Supplementation with thyroid hormone blocked the CoMP-related decrease. The flavin-containing monooxygenase was decreased by CoMP and by castration, and the decrease was not blocked by the thyroid hormone supplement. Thus in the rat, the CoMP-related decreases in thyroid hormone and testosterone decrease flavoproteins that support or mediate monooxygenase activities. This is contrary to the reported specificity of this class of compound as inhibitors of cytochrome P-450.
Science Education and Information Literacy: A Grass-Roots Effort to Support Science Literacy in Schools

This article reports how two academic librarians at a large state institution in California developed and implemented an information literacy program including the application of Web 2.0 tools for preservice science teachers. The article also explores definitions of science literacy, the evolving science curriculum, and standards for information literacy.
Dentists' preferred sources of new drug information and their attitudes toward the use of drugs by patients

Abstract This study, essentially a replication of an earlier study of physicians, reports an analysis of the relationship between dentists' new drug information source preferences and attitudes concerning the use of drugs by patients. Data, collected via questionnaire from 78 dentists in a Southeastern state, disclosed that Physician's Desk Reference was the major source used for learning about new drugs. Recommendation by colleagues was chosen as the second most preferred source. No statistical evidence was found to support either of the following hypotheses: (1) dentists preferring professional sources will be less likely to feel that medication advice from nondental sources is acceptable than dentists preferring commercial sources; and (2) dentists preferring professional sources will be more likely to express conservative attitudes about what constitutes legitimate use of drugs by patients than dentists preferring commercial sources. Evidence was found that general practitioners are less accepting of the use of mood-altering drugs than specialists. The results are compared with the previous study and possible explanations for the observed differences are presented.
Kinetic evidence for involvement of two cytochrome b-563 hemes in photosynthetic electron transport☆

Abstract The effect of 2-( n -heptyl)-4-hydroxyquinoline N -oxide (HQNO) on the kinetics of cytochrome b -563 and cytochrome c † turnovers following single-turnover flashes was measured in isolated heterocysts. Low concentrations of HQNO (below 3 μM) blocked reoxidation of cytochrome b -563, whereas higher concentrations (above 5 μM) resulted in additional inhibition of cytochrome b -563 oxidation and also inhibited reduction of cytochrome b -563 and cytochrome c . Similar effects on cytochrome b -563 reduction and reoxidation were obtained with a combination of 5 μM HQNO and 2,5-dibromo-3-methyl-6-isopropyl- p -benzoquinone (1–7 μM). In HQNO-inhibited heterocysts, cytochrome c reduction following a flash occurred in three phases with half-times of 0.5, 2.8 and 45 ms. The second phase nearly equalled the cytochrome b -563 reduction in half-time and magnitude. In the presence of HQNO, the reoxidation of cytochrome b -563 following two closely spaced actinic flashes displayed biphasic kinetics. The two phases correspond to reoxidation of cytochrome b -563 in which one or both of the cytochrome b -563 hemes in the cytochrome b–f complex are reduced. These results are interpreted in terms of a Q-loop in which HQNO, at low concentrations, blocks the site of rapid cytochrome b -563 reoxidation and at higher concentrations, also inhibits the site of electron donation by plastoquinol to the cytochrome b-f complex.
PROTONATION EFFECTS ON THE EQUILIBRIUM AND DYNAMICAL PROPERTIES OF THE ALANINE TETRAPEPTIDE

The effect of terminal group charge on the structure and dynamics of the alanine tetrapeptide has been investigated using molecular dynamics simulations. Neutral and positive N-termini, together wi...
Windows® Directory Entries for 8.3 Names in VFAT File Systems

In Windows operating systems, a long file name (VFAT entry) may or may not be generated for a file name which is short (8.3). For recent versions of Windows this depends upon the capitalization of the name and extension. A description of when and how this is done is given. The forensics implications of this are discussed.
Saudi Guidelines on the Diagnosis and Treatment of Pulmonary Hypertension: Pulmonary arterial hypertension associated with connective tissue diseases.

The explosive growth of medical literature on pulmonary hypertension (PH) has led to a steady increase in awareness of this disease within the medical community during the past decade. The recent revision of the classification of PH is presented in in the main guidelines. Group 1 PH or pulmonary arterial hypertension (PAH) is a heterogeneous group and includes PH due to inheritable, drug-induced, and toxin-induced causes and to such underlying systemic causes as connective tissue diseases, human immunodeficiency viral infection, portal hypertension, congenital heart disease, and schistosomiasis. Systemic sclerosis (SSc) is an autoimmune multisystem disorder, which affects over 240 persons per million in the United States. [1] Its manifestations are not confined to the skin but may also involve the lungs, kidneys, peripheral circulation, musculoskeletal system, gastrointestinal tract, and heart. The outcome of PAH associated with SSc is worse when compared to other subtypes of PAH. In this review, we summarize available information about the pulmonary vascular and cardiac manifestations of SSc with special emphasis on their prognostic implications as well as the peculiarity of their detection.
HOW LATE CAN YOU UPDATE? DETECTING BLUR AND TRANSIENTS IN GAZE- CONTINGENT MULTI-RESOLUTIONAL DISPLAYS

Lester C. Loschky Kansas State University Manhattan, KS George W. McConkie University of Illinois at Urbana-Champaign Champaign, IL This study investigated perceptual disruptions in gaze-contingent multi-resolutional displays (GCMRDs) due to delays in updating the image after an eye movement. GCMRDs can be used to save processing resources and transmission bandwidth in many single-user display applications such as virtual reality, simulators, video-telephony, remote piloting, and teleoperation. The current study found that image update delays after an eye movement could be as long as 60 ms without significantly increasing the detectability of image degradation and/or transients due to the update. This is good news for designers of GCMRD applications, since it is ample time to update their displays after an eye movement without disrupting perception. Users of virtual reality, simulators, video-telephony, remote piloting, teleoperation, and other single-user applications often need large, high-resolution displays exceeding limits on transmission bandwidth and/or computation resources. One way around these limitations is to eliminate detail that users cannot resolve in the visual periphery. Gaze-contingent multi-resolutional displays (GCMRDs) do just that, by dynamically displaying high resolution where the user is looking, as indicated by a gaze-tracker, and lower resolution elsewhere (Reingold
Multiple nonanastomotic aneurysms in an external velour ringed Dacron femoropopliteal vascular prosthesis

Nonanastomotic aneurysms of arterial prosthetic grafts are an infrequent but well-documented complication of arterial bypass surgery. Several cases of nonanastomotic aneurysm formation of the external velour-type Dacron graft have been reported. We present a case of an external velour ringed Dacron (Sauvage EXS) femoropopliteal bypass graft with multiple nonanastomotic aneurysms. An extensive review of the English literature shows this to be the first reported case of multiple aneurysms occurring in this type of prosthesis.
Immunosurveillance and Melanoma

There is considerable indirect and some direct evidence that immune mechanisms can play an important role in controlling the growth of melanoma. In mice, melanoma can be prevented with vaccines. Consequently, even though naturally occurring immunosurveillance may not be sufficiently potent to prevent melanoma, it is possible that the prophylactic augmentation of immunity to melanoma with vaccines may eventually permit this cancer to be prevented in humans.
Transcription termination at λ tR1 is mediated by interaction of Rho with specific single-stranded domains near the 3' end of cro mRNA

To determine whether E. coli rho protein mediates termination of transcription by interacting with specific segments of the nascent transcript, DNA oligonucleotides were used to sequester segments of phage lambda cro mRNA in hybrid helices. Formation of hybrids was demonstrated with RNAase H assays. Oligonucleotides complementary to either of two distinct, single-stranded sequences near the 3' end inhibited rho action at tR1, while oligonucleotides complementary to the sequence between those segments or to more 5' segments did not. The inhibitory oligonucleotides did not affect the elongation of cro mRNA or rho action on other transcripts. The results indicate that termination of transcription at tR1 is dependent upon contact of rho factor with specific, single-stranded domains near the 3' end of cro mRNA.
Non-invasive method to quantify local bacterial concentrations in a mixed culture biofilm

To better engineer and analyze beneficial biofilms as well as to develop strategies to control detrimental biofilms (e.g., biomedical device-based infections), it is critical to quantify bacterial species compositions within biofilms. A non-invasive method is described here that determines local and overall bacterial concentrations within a biofilm, using optical microscopy and digital image analysis techniques. The method is based upon a calibration of cell fluorescence to known cell number concentrations and is verified by direct cell counts of destructive samples of cultivated biofilms. Two GFP mutants, each with unique emission colors were used with both epi-fluorescent microscopy and one-photon confocal microscopy to determine local spatial biofilm cell concentrations in pure and mixed-strain biofilms. Our microbial system comprises Pseudomonas putida containing either green fluorescent protein (GFP) or containing the red fluorescent protein (DsRed). Strains expressing a green or red fluorescent protein were detected by two different microscopy methods: epi-fluorescence and single-photon confocal laser scanning microscopy. Overall biofilm cell concentrations determined directly from destructive samples were in good agreement with non-invasive measurements of adherent cell concentrations calculated from the measured “integrated fluorescent density” minus any background fluorescence. Results show the areal cell concentration (cell number/area) determined from non-destructive direct counts in a pure culture or binary-strain biofilm varied with the biofilm depth. Use of this method to estimate local dynamic plasmid segregational loss and plasmid conjugation transfer kinetics will be reported in a subsequent manuscript.
Performance of Beamspace Transmit Diversity Technique in Two Beam Rayleigh Fading Channels

Many theories of exploiting spatial diversity in wireless communications and more recently space-time coding are results of understanding the spatial channel models for antenna array communication systems. For example, the models for rich scattering environments assume the channel coefficients to be almost independent when the spacing between the antennas is sufficient. This could limit the possibility of extracting direction of the signal propagation with respect to antenna locations (G. Xu et al., IEEE Transactions on Signal Processing, Vol. 42, No. 2, pp. 349–355, 1994). On the other hand, when the scattering is limited to few dominant reflectors, the directions of the signals traveling through the environment can prevail in the channel coefficients. Extracting the propagation direction (beam direction) information from the channel coefficients has been investigated extensively in array signal processing literature. These investigations have led to many algorithms of direction of arrival (DOA) estimation and beamforming. Here, we propose a transmit diversity technique that exploits beam directions in environments with few beam directions. While we present this technique for two-beam Rayleigh fading channels (J.E. Mazo, IEEE Transaction on Communication, Vol. 39, No. 7, pp. 1027–1030, 1991), it can be easily extended to multibeam general fading channels. The proposed method does not require feedback from the receiver.
Gas permeability of hollow fiber membranes in a gas-liquid system

Abstract Designing an effective intravenous membrane oxygenator requires selecting hollow fiber membranes (HFMs) which present minimal resistance to gas exchange over extended periods of time. To evaluate HFMs, we developed a simple apparatus and methodology for measuring HFM permeability in a gas-liquid environment which has the capability of studying a variety of fiber types in any liquid of interest, such as blood. Using this system, we measured the O2 and CO2 exchange permeabilities of Mitsubishi MHF 200L composite HFMs and KPF 280E microporous HFMs in water at 37°C. The membrane permeability measured for the MHF 200L composite fiber was 7.9 × 10−6 ml/s/cm2/cmHg for O2 and 8.4 × 10−5 ml/s/cm2/cmHg for CO2, and for the KPF 280E microporous fiber, 1.4 × 10−5 ml/s/cm2/cmHg for O2 and 3.2 × 10−4 ml/s/cm2/cmHg for CO2. The permeabilities of the microporous HFMs were over two orders of magnitude less than what would be measured in a gas-gas system due to liquid infiltration of the pores, emphasizing the importance of measuring permeability in a gas-liquid system for relevant applications such as intravenous oxygenation. Furthermore, both O2 and CO2 permeabilities of the microporous fiber were consistent with a liquid infiltration depth of only 1%. The O2 permeability of the MHF fiber was found to be less than the overall exchange permeability ultimately required of our intravenous oxygenation device (K ≈ 1 × 10−5 ml(STP)/s/cm2/cmHg). Consequently, the MHF 200L composite fiber appears unsuitable for intravenous oxygenation devices such as ours.
Limiting similarity for coexistence of lake herring (Coregonus artedii) and chubs (Coregonus hoyi)

Abstract A simple food competition model was applied to calculate the limiting similarity for coexistence of lake herring and chubs in Lake Superior in terms of mortality and diet overlap. The results indicate that species can coexist over a wide range of diet overlap and mortality. In communities with high diet overlap change in mortality could have an effect on the outcome of competition, whereas in other communities the species would continue to coexist but with changes in relative abundances of species. The outcome of competition between lake herring and chubs was simulated with a moderate diet overlap which allows coexistence with a large increase in lake herring mortality. The patterns in the simulated abundances were similar to the patterns in the catch per unit of effort data.
On the Poisson geometry of the Adler-Gel’fand-Dikii brackets

In this paper, we consider a symplectic leaf that goes through a singular point of the Adler-Gel’fand-Dikii Poisson bracket associated to SL(n,R). We find a finite-dimensional transverse section2 at the singular point and we prove that one can induce a Poisson structure on2 (the transverse structure) that is linearizable and equivalent to the Lie-Poisson structure on sl(n,R)*. This problem is closely related to finding normal forms for nth order scalar differential operators with periodic coefficient. We partially generalize a well-known result for Hill’s operators to the higher order case.
Self-assembly of microporous manganese oxide octahedral molecular sieve hexagonal flakes into mesoporous hollow nanospheres.

Manganese oxide hollow nanospheres were prepared using a straightforward, template-free synthesis. The resulting material was mesoporous, crystalline, and of uniform diameter. The nanospheres were characterized by XRD, HR-SEM, and HR-TEM, and pore size distributions were calculated from nitrogen desorption. Unlike previous synthesis methods that use an inorganic template, this procedure requires no separation after synthesis to remove the template. The nanospheres are composed of hexagonal γ-manganese oxide flakes and are approximately 400 nm in diameter. γ-MnO2 is composed of a ramsdellite matrix (1 × 2 tunnels) with randomly distributed microdomains of pyrolusite (1 × 1 tunnels). These materials could have applications as cathodic battery materials, oxidation catalysts, catalyst supports, and adsorbents for pollutants.
Dynamic Interaction of S5 and S6 during Voltage-Controlled Gating in a Potassium Channel

A gain-of-function mutation in the Caenorhabditis elegans exp-2 K+-channel gene is caused by a cysteine-to-tyrosine change (C480Y) in the sixth transmembrane segment of the channel (Davis, M.W., R. Fleischhauer, J.A. Dent, R.H. Joho, and L. Avery. 1999. Science. 286:2501–2504). In contrast to wild-type EXP-2 channels, homotetrameric C480Y mutant channels are open even at −160 mV, explaining the lethality of the homozygous mutant. We modeled the structure of EXP-2 on the 3-D scaffold of the K+ channel KcsA. In the C480Y mutant, tyrosine 480 protrudes from S6 to near S5, suggesting that the bulky side chain may provide steric hindrance to the rotation of S6 that has been proposed to accompany the open-closed state transitions (Perozo, E., D.M. Cortes, and L.G. Cuello. 1999. Science. 285:73–78). We tested the hypothesis that only small side chains at position 480 allow the channel to close, but that bulky side chains trap the channel in the open state. Mutants with small side chain substitutions (Gly and Ser) behave like wild type; in contrast, bulky side chain substitutions (Trp, Phe, Leu, Ile, Val, and His) generate channels that conduct K+ ions at potentials as negative as −120 mV. The side chain at position 480 in S6 in the pore model is close to and may interact with a conserved glycine (G421) in S5. Replacement of G421 with bulky side chains also leads to channels that are trapped in an active state, suggesting that S5 and S6 interact with each other during voltage-dependent open-closed state transitions, and that bulky side chains prevent the dynamic changes necessary for permanent channel closing. Single-channel recordings show that mutant channels open frequently at negative membrane potentials indicating that they fail to reach long-lasting, i.e., stable, closed states. Our data support a “two-gate model” with a pore gate responsible for the brief, voltage-independent openings and a separately located, voltage-activated gate (Liu, Y., and R.H. Joho. 1998. Pflugers Arch. 435:654–661).
Switching in amorphous alloys

Abstract In this paper we present a survey of recent developments in the field of memory switching and of recent insights into the mechanism of threshold switching, in “ovonic” multicomponent chalcogenide alloys.
The gas-phase reactions of metal porphyrins with diazoacetate esters

Abstract The Mn(III), Fe(III) and Co(III) complexes of tetraphenylporphyrin were allowed to react with ethyl and t -butyl diazoacetate in an ion trap mass spectrometer. The manganese system produces only adducts, but the iron and cobalt systems give addition with loss of N 2 to produce carbene-like species. All the reactions are fast and approach the collision-controlled limit. Fragmentation of the iron and cobalt carbene species follow three major pathways: (a) alkene loss from the ester to give a carboxylic acid (which can subsequently decarboxylate to give CH 2 complexed to the metal porphyrin), (b) homolytic cleavage of the ester O R bond with loss of CO 2 and an alkyl radical to produce CH complexed to the metal porphyrin, and (c) alcohol loss to give C C O complexed to the metal porphyrin. Computational data from density functional theory (B3LYP) are consistent with the observed reactivity trends and indicate that all the carbene complexes prefer a M N insertion structure where the carbene carbon bonds to the metal and one of the porphyrin nitrogens (metal nitrogen bond is lost). The M N insertion structures are generally more than 25 kcal/mol more stable than the conventional metal carbene structures, M C, at the B3LYP level and should dominate their reactivity.
Moving boundary electrophoretically mediated microanalysis

Abstract Moving boundary sample introduction is described as an alternative to zonal injection methods for the electrophoretically mediated microanalysis (EMMA) of leucine aminopeptidase (LAP). The capillary was initially filled with the analyte solution while the fastermigrating substrate, l -leucine- p -nitroanilide, was maintained in the inlet reservoir. Upon application of an electric field, electrophoretic merging of the reagents proceeded, and the detectable reaction product, p -nitroaniline, was transported to the detector. The area, maximum height, inclining slope, and declining slope of the resulting triangular product profile were each directly proportional to the activity of LAP, and the observed migration times of the product profile features defined the volume and time of the incubation. The moving boundary technique offered more than an order of magnitude greater concentration sensitivity than the zonal injection EMMA method. This heightened sensitivity facilitated rapid analysis as the use of elevated electric field strengths and short capillaries allowed for a 24-s kinetic determination of LAP.
Analysis of relationships between pericytes and gas exchange capillaries in neonatal and mature bovine lungs.

Abstract Neonatal and mature bovine lungs were examined ultrastructurally to quantitatively assess pericyte envelopment of gas exchange capillaries and proximities of pericyte margins to endothelial cell junctions. Pericytes were observed on 91% of the cross-sectioned capillary profiles examined, with 18 and 26% coverage in neonatal and mature lungs, respectively. Chi-square analysis indicated a random occurrence of endothelial cell junctions under pericytes; however, pericyte processes tended to end near endothelial cell junctions. In the neonatal and mature lungs, 38 and 40%, respectively, of all endothelial junctions were within 0.5 μm of the margins of pericyte processes; such distances covered only 16 and 17% of the circumferences of the capillary profiles examined. Thus, endothelial cell junctions were located near pericyte margins over twice as often as would occur in a random distribution. If pericytes are contractile cells, as recent research indicates, they may function as regulators of lymph formation by influencing the permeability of endothelial cell junctions in the gas exchange capillaries.
Neointimal hyperplasia following argon ion laser carotid endarterectomy: with and without endothelial cell seeding.

Background and Objective This study compares the development of neointimal hyperplasia following conventional and argon ion laser carotid endarterectomy and assesses the potential advantage of endothelial cell seeding. Study Design/Materials and Methods: Eight dogs underwent conventional endarterectomy in one carotid artery and an argon ion laser endarterectomy in the other. After 42 days, these arteries were harvested and the intimal thicknesses were compared. Six additional dogs underwent bilateral argon ion laser carotid endarterectomy with endothelial cell seeding on one side only. These arteries were harvested after 65 days and their mean intimal thicknesses were compared. Results At 42 days, the mean intimal thickness in the conventional endarterectomy group was 0.070±0.007 mm; in the argon ion laser endarterectomy group it was 0.058±0.001 mm (P=0.76, NS). AT 65 days, the mean intimal thickness in the group without endothelial cell seeding was 0.125±0.003 mm vs. 0.061±0.001 mm on the seeded side (P=0.043). Conclusion Argon ion laser carotid endarterectomy results in no more neointimal hyperplasia than conventional endarterectomy. The neointimal hyperplasia is reduced by endothelial cell seeding. Lasers Surg. Med. 20:367–372, 1997. © 1997 Wiley-Liss, Inc.
Causes and Consequences of Teacher Moonlighting

Causes and consequences of teacher moonlighting are investigated, using a nationwide survey of US teachers conducted in the mid-1980s. A model of teacher time allocation is estimated by maximum likelihood methods. Moonlighting is shown to be highly insensitive to levels of teacher pay, even when controlling for variations in costs of living and local labor market conditions. However, teachers who moonlight do not appear to shortchange their students when it comes to preparing lessons, grading papers or assigning homework.
More game-theoretic properties of Boolean algebras

Abstract The following infinite game G was investigated in [5]: Let B be a Boolean algebra. Two players, White and Black, take turns to choose successively a sequence
Serum prolactin and LH in early phases of delayed versus direct pseudopregnancy in the rat.

Delayed or direct pseudopregnancieswere induced by electrical stimulation of the cervixat 1400 h on diestrus day 2 (D-2) or on estrus,respectively. Blood samples for measurement ofprolactin and LH by radioimmunoassay were collectedby rapid decapitation at 5, 15, 30, 45 or 60min after cervical stimulation or thereafter at 3-hintervals throughout the first 6 days of leukocyticvaginal smears of pseudopregnancy (PSP L-l toL-6). For comparison, untreated animals were decapitatedat the same 3-h intervals throughout the4-day cycle. Serum LH concentrations in all the experimentalanimals did not vary from those measured in thecyclic controls. Compared with the normal cycle, prolactin (PRL)levels were not different until 10 h after cervicalstimulation during estrus. After stimulation on D-2,PRL secretion did not differ from that in the normalcycle until approximately 37 h later, when there wasa short rise following the usual proestrus surge. In both direct and delayed pseudopregnancy,twice-daily PRL surges appeared...
Diophantine undecidability in some rings of algebraic numbers of totally real infinite extensions of Q

Abstract This paper provides the first examples of rings of algebraic numbers containing the rings of algebraic integers of the infinite algebraic extensions of Q where Hilbert's Tenth Problem is undecidable.
Measurement of ϵ-N-trimethyllysine in human blood plasma and urine☆

A method for measurement of epsilon-N-trimethyllysine in human blood plasma and urine is described. An internal standard, delta-N-trimethylornithine, was added to plasma and urine specimens and the mixtures were deproteinized and/or hydrolyzed. Preliminary purification of epsilon-N-trimethyllysine and delta-N-trimethylornithine was achieved by sequential cation-exchange--anion-exchange chromatography. Amino acids in the column eluates were derivatized with o-phthalaldehyde and mercaptoethanol, and were separated by isocratic reversed-phase high-performance liquid chromatography in the presence of an ion-pairing reagent. Quantitation was achieved by post-column fluorometry. The limit of detection was 5 pmol of epsilon-N-trimethyllysine injected into the chromatograph. The procedure was suitable for determination of epsilon-N-trimethyllysine in 1 ml of plasma or 0.2-0.4 ml of urine. The method was applied to measurements of epsilon-N-trimethyllysine in plasma and urine of four systemic carnitine deficiency patients and six normal subjects. Plasma epsilon-N-trimethyllysine concentration was significantly lower in systemic carnitine deficiency patients compared to normal individuals, but no significant difference in urinary epsilon-N-trimethyllysine excretion was observed between the two groups.
Theoretical review: altered pain regulatory systems in chronic pain.

Abstract This review synthesizes the existing literature regarding the relationship between resting blood pressure and pain sensitivity, and the literature indicating possible endogenous opioid dysfunction in chronic pain. Adaptive interactions between the cardiovascular and pain regulatory systems occur in healthy individuals, with greater blood pressure associated with decreased acute pain sensitivity. Endogenous opioids appear necessary for full expression of this relationship. There is ample evidence indicating diminished endogenous opioid CSF/plasma levels in chronic pain patients, yet little is known about the functional effects of these opioid changes. A theoretical model is proposed based upon the literature reviewed suggesting progressive dysfunction in endogenous opioid systems with increasing chronic pain duration. This dysfunction is hypothesized to result in dysregulation of normally adaptive relationships between the cardiovascular and pain regulatory systems, resulting in increased chronic pain intensity and increased acute pain sensitivity among chronic pain patients. Preliminary data are consistent with the hypothesis of progressive opioid changes resulting in dysfunctional alterations in the adaptive blood pressure–pain relationship. Clinical implications of this theory are discussed.
High Vascular Tone of Mouse Femoral Arteries In Vivo Is Determined by Sympathetic Nerve Activity Via α1A- and α1D-Adrenoceptor Subtypes

Background and purpose Determining the role of vascular receptors in vivo is difficult and not readily accomplished by systemic application of antagonists or genetic manipulations. Here we used intravital microscopy to measure the contributions of sympathetic receptors, particularly α1-adrenoceptor subtypes, to contractile activation of femoral artery in vivo. Experimental approach Diameter and intracellular calcium ([Ca(2+)]i) in femoral arteries were determined by intravital fluorescence microscopy in mice expressing a Myosin Light Chain Kinase (MLCK) based calcium-calmodulin biosensor. Pharmacological agents were applied locally to the femoral artery to determine the contributions of vascular receptors to tonic contraction and [Ca(2+)]i,. Key results In the anesthetized animal, femoral arteries were constricted to a diameter equal to 54% of their passive diameter (i.e. tone = 46%). Of this total basal tone, 16% was blocked by RS79948 (0.1 µM) and thus attributable to α2-adrenoceptors. A further 46% was blocked by prazosin (0.1 µM) and thus attributable to α1-adrenoceptors. Blockade of P2X and NPY1 receptors with suramin (0.5 mM) and BIBP3226 (1.0 µM) respectively, reduced tone by a further 22%, leaving 16% of basal tone unaffected at these concentrations of antagonists. Application of RS100329 (α1A-selective antagonist) and BMY7378 (α1D-selective) decreased tone by 29% and 26%, respectively, and reduced [Ca(2+)]i. Chloroethylclonidine (1 µM preferential for α1B-) had no effect. Abolition of sympathetic nerve activity (hexamethonium, i.p.) reduced basal tone by 90%. Conclusion and implications Tone of mouse femoral arteries in vivo is almost entirely sympathetic in origin. Activation of α1A- and α1D-adrenoceptors elevates [Ca(2+)]i and accounts for at least 55% of the tone.
DETERRENCE EFFECTIVENESS MEASUREMENT

The controversy of statistical evaluation of effectiveness of the present criminal justice system and of specific programs or changes implemented in the existing system has in part centered around the value of crime-incidence data. The relationships between victimization and UCR or police-blotter data pertinent to their use in evaluation are first described. An example is presented using an empirical-stochastic model developed solely from UCR data to illustrate an approach to evaluation of system effectiveness. Here an ad hoc procedure is displayed which quantifies variation in and/or shifts in crime patterns after an intervention in the system.