cssi/SciSciGPT-SciSciNet huggingface dataset:
Characterization of Sec-Translocon-Dependent Extracytoplasmic Proteins of Rickettsia typhi

As obligate intracellular, vector-borne bacteria, rickettsiae must adapt to both mammalian and arthropod host cell environments. Deciphering the molecular mechanisms of the interactions between rickettsiae and their host cells has largely been hindered by the genetic intractability of these organisms; however, research in other gram-negative pathogens has demonstrated that many bacterial determinants of attachment, entry, and pathogenesis are extracytoplasmic proteins. The annotations of several rickettsial genomes indicate the presence of homologs of the Sec translocon, the major route for bacterial protein secretion from the cytoplasm. For Rickettsia typhi, the etiologic agent of murine typhus, homologs of the Sec-translocon-associated proteins LepB, SecA, and LspA have been functionally characterized; therefore, the R. typhi Sec apparatus represents a mechanism for the secretion of rickettsial proteins, including virulence factors, into the extracytoplasmic environment. Our objective was to characterize such Sec-dependent R. typhi proteins in the context of a mammalian host cell infection. By using the web-based programs LipoP, SignalP, and Phobius, a total of 191 R. typhi proteins were predicted to contain signal peptides targeting them to the Sec translocon. Of these putative signal peptides, 102 were tested in an Escherichia coli-based alkaline phosphatase (PhoA) gene fusion system. Eighty-four of these candidates exhibited signal peptide activity in E. coli, and transcriptional analysis indicated that at least 54 of the R. typhi extracytoplasmic proteins undergo active gene expression during infections of HeLa cells. This work highlights a number of interesting proteins possibly involved in rickettsial growth and virulence in mammalian cells.
The Long-Run Dynamic of the Nexus between Military Strength and National Power: An Econometric Analysis

A number of literatures suggest that military strength has been losing centrality and importance to nonmilitary factors of national power. In this paper, logistic regressions and data from the Correlates of War (COW) project are used to investigate whether over the 18202000 time horizon, for the great powers and their proximate contenders, the importance of military capabilities to national power has declined vis-a-vis that of economic capabilities. Estimation was carried out using generalized estimating equations (GEEs). The overall picture that emerges from the analysis is that of a transition in progress from a systemic state in which military capabilities were the dominant determinants of national power to a state in which economic capabilities will become the dominant ones. The analysis is concerned with long-run trends, and its results are not necessarily applicable to specific countries and circumstances.
Relationships among Headspace Oxygen, Peroxide Value, and Conjugated Diene Content of Soybean Oil Oxidation

ABSTRACT: Relationships among headspace oxygen uptake, peroxide value, and conjugated dienes content in the oxidation of soybean oils in a gas-tight bottle were studied for 24 h under light and 96 h in the dark at 55°C. The theoretical peroxide value determined by oxygen uptake continuously increased as storage time increased. The headspace oxygen method is simple and reproducible and may be the best analytical method to evaluate the oxidative stability of oils.
Tunable Nanoscale Graphene Magnetometers

The detection of magnetic fields with nanoscale resolution is a fundamental challenge for scanning probe magnetometry, biosensing, and magnetic storage. Current technologies based on giant magnetoresistance and tunneling magnetoresistance are limited at small sizes by thermal magnetic noise and spin-torque instability. These limitations do not affect Hall sensors consisting of high mobility semiconductors or metal thin films, but the loss of magnetic flux throughout the sensor's thickness greatly limits spatial resolution and sensitivity. Here we demonstrate graphene extraordinary magnetoresistance devices that combine the Hall effect and enhanced geometric magnetoresistance, yielding sensitivities rivaling that of state of the art sensors but do so with subnanometer sense layer thickness at the sensor surface. Back-gating provides the ability to control sensor characteristics, which can mitigate both inherent variations in material properties and fabrication-induced device-to-device variability that is unavoidable at the nanoscale.
A two-stage Monte Carlo approach to the expression of uncertainty with non-linear measurement equation and small sample size

In this paper we propose a two-stage Monte Carlo procedure that explicitly takes into account the finite sample sizes used to estimate parameters of the input distributions of non-linear measurement equations. We will illustrate the approach with a case study involving the efficiency of a thermistor mount power sensor. The performance of the proposed approach will be compared with the standard GUM (US Guide to the Expression of Uncertainty in Measurement, American National Institute of Standards, ANSI/NCSL Z540-2-1997) approach for finite samples using simple linear and non-linear measurement equations. We will investigate performance in terms of coverage probabilities of derived coverage intervals for the mean of the measurand. Proposed Supplement 1 to the GUM (Guide to the Expression of Uncertainty in Measurement, Supplement 1, currently under review to the member organizations of the JCGM and the national measurement institutes (draft 3rd edn)) outlines a 'propagation of distributions' approach to deriving the distribution of a measurand for any non-linear function and for any set of random inputs. The Supplement's approach assumes that the distributions of the random inputs are known exactly. In practice, however, the distributions of the inputs will rarely be known exactly but must be estimated using possibly small samples. The two-stage Monte Carlo approach will be compared with the GUM Supplement's propagation of distribution approach for non-linear measurement equations. We will show that the GUM Supplement's approach underestimates uncertainty in the measurand if distributions estimated with small sample sizes are assumed to be known exactly.
Grief: a mediating process between a loss and illness.

Abstract Conjugal bereavement has ranked high among other losses and life events when rated by adults on a continuum of life stress.1,2 A review of the literature on the mortality of bereaved spouses subsequent to a conjugal loss leads to the conclusion that such a loss is, in fact, a severe stressor and a significant public health problem.3 There remains the question of how this loss affects the bereaved spouse. Loss of a conjugal partner is a well defined event that is followed by complex emotional, behavioral, and social reactions. At what point and in what manner grief itself becomes pathologic or leads to medical complications is not established. Yet, it is reasonable to postulate that the behavioral and physiologic responses of the organism to a conjugal loss may lead to complications. For this reason, the emotional, behavioral, and social changes produced by conjugal loss hold considerable interest as mediating variables in explaining the high risk of the bereaved. This paper will review modern thinking about the process of grief. It will relate that knowledge to several postulated pathogenetic mechanisms that lead to illness and death among the widowed. The goal is to determine if our knowledge of grief as a mediating process will enhance our understanding of the etiology of the psychological or bodily illness that may occur after a conjugal loss.
On finding the core of a tree with a specified length

Abstract A core of a graph G is a path P in G that is central with respect to the property of minizining d ( P ) = Σ υϵV ( G ) d ( υ , P ), where d ( υ , P ) is the distance from vertex υ to path P . This paper explores some properties of a core of a specified length.
Computer-assisted system for the reconstruction of shattered objects

Reconstruction for forensic purposes of shattered or otherwise damaged objects has been a painstaking, if not impossible, undertaking. The forensic crime scientist and the archaeologist share this challenge. A pilot project, funded by the National Institute of Justice experimented with several avenues of approach to this problem of reassembly by using the 627 fragmented pieces of a pane of glass from a crime scene. I was approached by staff members of the Forensic Laboratory of the Minnesota Bureau of Criminal Apprehension because I was developing a means to restore a Greek Bronze Age wall painting (ca. 1350 B.C.E.) fragmented into 4750 pieces and a Greek temple (ca. 150 B.C.E.) demolished by vandals about 1500 years ago, leaving behind 1485 stone blocks, 1-3 tons each. The challenge was to develop an automated method to rapidly and effectively analyze a quantity of fragments of like kind separated one from the other and from the original object by violence and other means. The project established a set of mathematically and graphically definable characteristics held by the glass sherds which allowed for the making of joins between pieces. Preparation included the formulation of inventory check-sheets and a barcode label system with a unique identifier for each piece based on a x,y,z grid system. The next step involved experimentation with an array of proprietary GIS, SQL, and CAD software alternatives for the processing of data. In the end we settled on maximum likelihood analysis of SQL filtered results. This and shape indices were complied using ArcView and the scripting language, Avenue, products of ESRI, Redlands, California.
LOCAL IRREGULARITIES IN AN EXPANDING UNIVERSE

Abstract Einstein's theory of gravitation is here applied to a model of the universe in which local irregularities ( h μν ) in the space-time metric are superimposed on the values appropriate to a uniform, isotropic universe. The mass tensor is taken to be that of a perfect fluid. The mass density is considered to fluctuate about a mean ϱ 0 , the density in the uniform model, but the fluctuations need not be small with respect to ϱ 0 . The effect of pressure is included. The system of simultaneous equqtions derived by Lanczos in 1925, which relates the irregularities in the metric to the irregularities in the mass tensor, is shown to simplify under conditions of astronomical interest. A generalized Poisson equation for h 44 results, in which only the fluctuating component of the mass tensor appears. The solution is obtained with the aid of the Green's function found by Whittaker in 1928, which reduces to the familiar form if space is flat. The equation of motion for the irregularities is derived in comoving coordinates (Eq. (35)). The fourth component of this equation leads to an energy equation involving the kinetic and potential energies of the irregularities and excluding the expanding substratum. This equation should be of significance to cosmogony. The relation of the local inertial coordinate system to the comoving system is examined. An approximate inertial system may be defined in a spatial region within which the square of the expansion velocity is much less than c 2 ; the expansion velocity need not be small relative to random local velocities. The local inertial system is determined by, and is nonrotating with respect to, the cosmic distribution of matter, so that Mach's principle is satisfied. The equation of motion in the inertial system (Eq. (72)) is derived. Its validity is not restricted to small pressures. For a particle at distance L from the chosen origin only the fluctuating component of ϱ at radii greater than L contributes to the gravitational force, while the total density within this radius has a gravitational effect. When the pressure may be neglected, the equation reduces to Newton's law of gravitation. The inclusion of steady-state cosmology within general relativity appears to lead to inadmissible results when local irregularities are present. Expressions for the cosmic pressure, density, and internal energy are derived in terms of local fluctuations in ϱ and velocity. p 0 has the form (Eq. (96)) that would be expected from the kinetic theory of fluids. The relation between cosmology and cosmogony is discussed.
Sparse sampling methods for efficient spatial coherence estimation

Short-lag spatial coherence (SLSC) imaging, a coherence-based alternative beamforming technique, creates images related to the spatial covariance in backscatter. Because spatial covariance estimation is a computationally intensive process, efficient techniques are crucial to implementing SLSC imaging in real-time. Sparse sampling methods that take advantage of the statistical properties of spatial covariance of backscatter may yield adequate images at substantially faster rates. Among a variety of sparse spatial sampling techniques, a uniformly spaced sampling scheme was found to generate SLSC images with highest fidelity. Nearly identical images could be formed using a small fraction (17%) of the aperture, corresponding to a 97.3% reduction in the number of covariance computations. Furthermore, sparse temporal sampling was implemented by replacing the axial kernel of length T (used to compute covariance) with a single sample, and yielded SLSC images with improved axial resolution with a T -fold reduction in computation time. The two techniques were combined to obtain even further improvements in computation speed with little or no image degradation.
Report On ‘Integrating Materials Science into the Chemistry Curriculum’

Working on the premise that materials science is justifiably an appropriate place to begin teaching chemistry, George Lisensky and Dean Campbell demonstrated in their workshop a series of introductory chemistry laboratory experiments with solid-state chemistry as the focus. For the bulk of the workshop, participants broke up into various size groups, simulating a chemistry laboratory session. A rational ordering of demonstrations in solid-state chemical paradigms to be covered in a typical laboratory section, from unit cells to band theory, was presented. At each stage, the materials used for the laboratory demonstrations were clearly defined, shown to be budget friendly, very safe, and robust enough for student use. All experiments impressed workshop participants that solid-state laboratories are feasible and accessible teaching tools with just as much ability to stimulate students as other fields of chemistry. All the while, a very effective methodology for teaching chemistry through solid-state concepts was demonstrated.
Combining explicitly correlated R12 and Gaussian geminal electronic structure theories.

Explicitly correlated R12 methods using a single short-range correlation factor (also known as F12 methods) have dramatically smaller basis set errors compared to the standard wave function counterparts, even when used with small basis sets. Correlations on several length scales, however, may not be described efficiently with one correlation factor. Here the authors explore a more general MP2-R12 method in which each electron pair uses a set of (contracted) Gaussian-type geminals (GTGs) with fixed exponents, whose coefficients are optimized linearly. The following features distinguish the current method from related explicitly correlated approaches published in the literature: (1) only two-electron integrals are needed, (2) the only approximations are the resolution of the identity and the generalized Brillouin condition, (3) only linear parameters are optimized, and (4) an arbitrary number of (non-)contracted GTGs can appear. The present method using only three GTGs and a double-zeta quality basis comput...
Episodic memory, semantic memory, and amnesia

Episodic memory and semantic memory are two types of declarative memory. There have been two principal views about how this distinction might be reflected in the organization of memory functions in the brain. One view, that episodic memory and semantic memory are both dependent on the integrity of medial temporal lobe and midline diencephalic structures, predicts that amnesic patients with medial temporal lobe/diencephalic damage should be proportionately impaired in both episodic and semantic memory. An alternative view is that the capacity for semantic memory is spared, or partially spared, in amnesia relative to episodic memory ability. This article reviews two kinds of relevant data: 1) case studies where amnesia has occurred early in childhood, before much of an individual's semantic knowledge has been acquired, and 2) experimental studies with amnesic patients of fact and event learning, remembering and knowing, and remote memory. The data provide no compelling support for the view that episodic and semantic memory are affected differently in medial temporal lobe/diencephalic amnesia. However, episodic and semantic memory may be dissociable in those amnesic patients who additionally have severe frontal lobe damage.
Multiple phosphorylation of Rad9 by CDK is required for DNA damage checkpoint activation.

The DNA damage checkpoint controls cell cycle arrest in response to DNA damage, and activation of this checkpoint is in turn cell cycle-regulated. Rad9, the ortholog of mammalian 53BP1, is essentia...
Relationship between the elastic properties and the order parameter of the spin-density wave phase of (TMTSF)2PF6

We present elastic constant data of the material (TMTSF) 2 PF 6 , with particular emphasis on the region about the phase transition, and at low temperatures. Specific heat, resistivity, and NMR measurements have indicated a very sharp transition at T SDW =12.1 K. Similarly sharp features have been observed in the temperature dependence of the Young's Modulus, followed by a continual stiffening below the transition. Comparison to recent NMR results indicate that the modulus varies as the square of the internal magnetic field below T SDW , thus constraining the form of the coupling of the order parameter to the strain field. There is no evidence for anomalies in the modulus below 4K, where it has been suggested that a transition to a commensurate state occurs
Design and Control of Distillation Columns with Intermediate Reboilers

Distillation columns in which the components being separated have widely different boiling points feature large temperature differences between the condenser and reboiler. If cooling water is used ...
Metabolism of 1-hydroxybenzo[a]pyrene

Abstract A metabolite of the known carcinogen benzo[ a ]pyrene (BP), 1-hydroxybenzo[ a ]pyrene 1-BPOH, is further metabolized by rat liver homogenate and microsomes. This oxidation is shown to be enzyme-catalyzed and dependent upon the presence of NADH and NADPH. Isolation of the final product yielded the BP-1,6-dione.
Are rivers just big streams? A pulse method to quantify nitrogen demand in a large river.

Given recent focus on large rivers as conduits for excess nutrients to coastal zones, their role in processing and retaining nutrients has been overlooked and understudied. Empirical measurements of nutrient uptake in large rivers are lacking, despite a substantial body of knowledge on nutrient transport and removal in smaller streams. Researchers interested in nutrient transport by rivers (discharge > 10 000 L/s) are left to extrapolate riverine nutrient demand using a modeling framework or a mass balance approach. To begin to fill this knowledge gap, we present data using a pulse method to measure inorganic nitrogen (N) transport and removal in the Upper Snake River, Wyoming, USA (seventh order, discharge 12 000 L/s). We found that the Upper Snake had surprisingly high biotic demand relative to smaller streams in the same river network for both ammonium (NH4+) and nitrate (N03~). Placed in the context of a meta-analysis of previously published nutrient uptake studies, these data suggest that large rivers may have similar biotic demand for N as smaller tributaries. We also found that demand for different forms of inorganic N (NH4+ vs. N03~) scaled differently with stream size. Data from rivers like the Upper Snake and larger are essential for effective water quality management at the scale of river networks. Empirical measurements of solute dynamics in large rivers are needed to understand the role of whole river networks (as opposed to stream reaches) in patterns of nutrient export at regional and continental scales.
HIV-1 Vif promotes the G1- to S-phase cell-cycle transition

HIV-1 depends on host-cell resources for replication, access to which may be limited to a particular phase of the cell cycle. The HIV-encoded proteins Vpr (viral protein R) and Vif (viral infectivity factor) arrest cells in the G2 phase; however, alteration of other cell-cycle phases has not been reported. We show that Vif drives cells out of G1 and into the S phase. The effect of Vif on the G1-to-S transition is distinct from its effect on G2, because G2 arrest is Cullin5-dependent, whereas the G1-to-S progression is Cullin5-independent. Using mass spectrometry, we identified 2 novel cellular partners of Vif, Brd4 and Cdk9, both of which are known to regulate cell-cycle progression. We confirmed the interaction of Vif and Cdk9 by immunoprecipitation and Western blot, and showed that small interfering RNAs (siRNAs) specific for Cdk9 inhibit the Vif-mediated G1-to-S transition. These data suggest that Vif regulates early cell-cycle progression, with implications for infection and latency.
The importance of cytochrome P450 2B6 in the human metabolism of environmental chemicals

Cytochrome P450 (CYP) 2B6 (CYP2B6) is a human CYP isoform found in variable amounts in the liver and other organs. It is known to be inducible and polymorphic and has a wide range of xenobiotic substrates. Studies of CYP2B6 to date have concentrated heavily on clinical drugs. In the present communication, however, we concentrate on its role in the metabolism of environmental xenobiotics. The term environment is used, in its broadest sense, to include natural ecosystems and agroecosystems as well as the industrial and indoor domestic environments. In essence, this excludes only clinical drugs and drugs of abuse. Many of these chemicals, including agrochemicals and industrial chemicals, can serve as substrates, inhibitors and/or inducers of CYP2B6, these activities being often modified by the existence of polymorphic variants. Metabolism-based interactions between environmental chemicals are discussed, as well as the emerging possibility of metabolic interactions between environmental chemicals and clinical drugs.
Dual Microwave Radar Vehicle Detection System at Four-Quadrant-Gate Railroad Grade Crossing

This paper presents the results of a study of the detection performance of a dual microwave radar vehicle detection system installed at a railroad grade crossing with four-quadrant gates. The system included two identical microwave radar units located at opposing quadrants of the crossing. Each unit covered approximately the same detection area. The objective of the dual radar installation was to increase system reliability by providing redundancy in detection. The performance of each radar unit alone and of the two units combined was assessed in terms of false calls, missed calls, stuck-on calls, and dropped calls. The system was first evaluated on the basis of the initial setup recommended by the distributor as the best. Those results were used to modify the system, which was evaluated again in its new configuration. Twelve days of data on more than 40,000 vehicles and more than 1,300 trains were analyzed. The most frequent type of error in the initial setup was false calls (0.54%), which were generated...
Effects of bark accumulation on benthic infauna at a log transfer facility in Southeast Alaska

Abstract Effects of bark accumulation are examined by comparing macro-infauna (numbers and biomass) at a log transfer facility with those of an adjacent unaffected region. The quantities of some infaunal species (and groups of species) are significantly different in ‘shallow’ vs ‘deep’ water zones, arbitrarily defined as 3–6 and 7–10 m below mean lower low water (MLLW), respectively. Bivalves and polychaetes dominate the fauna of both areas, but are significantly diminished under bark deposits. Results indicate that a complete covering of bark debris can have drastic effects on the structure of benthic communities. In extreme conditions macro-infauna can be virtually eliminated, in less severe instances, deposit feeders replace suspension feeders.
Formic hydrogenlyase. Activation in nonproliferating suspensions of Escherichia coli.

Abstract A number of activators and inhibitors of the formic hydrogenlyase enzyme system of Escherichia coli , strain B, are presented and discussed. It was found that in resting cells the rate and magnitude of hydrogen evolution from formate could be increased by the addition of phosphate, ammonium sulfate, histamine, histidine, sulfathiazole, p -aminobenzoic acid, and aminopterin. Sodium arsenate inhibited this reaction. These effects are discussed in relation to known activators of the hydrogenlyase system.
Parental Attachment and Peer Relations in Adolescence: A Meta-Analysis

Using Bowlby's (1988) theory of attachment relations in this meta-analytic study, we examined prior studies that assessed both parental attachment and peer relations during adolescence. The collective sample size reflects 12,482 participants across 53 studies conducted since 1970. The overall effect size between parental attachment and adolescent peer relations variables was approximately ½ SD (d =. 54). Analysis of specific peer relations dimensions indicates that parental attachment was related to both social competence and best friend relationship quality. Despite variations in study characteristics, this overall effect size appears remarkably stable. Studies that have employed higher proportions of Whites and female participants, North American samples, and measures with high reliability have yielded relatively higher effect sizes than comparison studies. The findings provide partial support for Bowlby's (1988) contention that the emotion-based interactions with parent figures have repercussions in ot...
Cloning and characterization of the majority of repetitive DNA in cotton (Gossypium L.).

Repetitive DNA elements representing 60–70% of the total repetitive DNA in tetraploid cotton (Gossypium barbadense L.) and comprising 30–36% of the tetraploid cotton genome were isolated from a genomic library of DNA digested with a mixture of four blunt-end cutting restriction enzymes. A total of 313 clones putatively containing nuclear repetitive sequences were classified into 103 families, based on cross hybridization and Southern blot analysis. The 103 families were characterized in terms of genome organization, methylation pattern, abundance, and DNA variation. As in many other eukaryotic genomes, interspersed repetitive elements are the most abundant class of repetitive DNA in the cotton genome. Paucity of tandem repeat families with high copy numbers (>104) may be a unique feature of the cotton genome as compared with other higher plant genomes. Interspersed repeats tend to be methylated, while tandem repeats seem to be largely unmethylated in the cotton genome. Minimal variation in repertoire and ...
Accounting for Inventory Carrying Costs

(1987). Accounting for Inventory Carrying Costs. The Journal of Cost Analysis: Vol. 5, No. 1, pp. 1-6.
Understanding the ‘active’ in ‘enactive’

Much recent work on cognition is characterized by an augmentation of the role of action coupled with an attenuation of the role of representation. This coupling is no accident. The appeal to action is seen either as a way of explaining representation or explaining it away. This paper argues that the appeal to action as a way of explaining, supplementing, or even supplanting, representation can lead to a serious dilemma. On the one hand, the concept of action to which we appeal cannot, on pain of circularity, be a representational concept. Such an appeal would presuppose representation and therefore can neither explain it nor explain it away. On the other hand, I shall argue, if the concept of action to which we appeal is not a representational one, there is every reason for supposing that it will not be the sort of thing that can explain, or supplement, let alone supplant, representation. The resulting dilemma, I shall argue, is not fatal. But avoiding it requires us to embrace a certain thesis about the nature of action, a thesis whose broad outline this paper delineates. Anyone who wishes to employ action as a way of explaining or explaining away representation should, I shall argue, take this conception of action very seriously indeed. I am going to discuss these issues with respect to a influential recent contribution to this debate: the sensorimotor or enactive model of perception developed by Kevin O’Regan and Alva Noe.
Coincidence formulas in enumerative geometry

(1979). Coincidence formulas in enumerative geometry. Communications in Algebra: Vol. 7, No. 16, pp. 1685-1711.
Relation between left ventricular oxygen consumption and pressure-volume area in conscious dogs.

BACKGROUND The relation between left ventricular (LV) oxygen consumption (MVO2) and pressure-volume area (PVA) developed in isolated hearts provides a powerful method to understand cardiac energetics. We investigated application of this relation to the intact circulation, determining its response to steady-state and transient load alterations and enhanced contractility in conscious animals. METHODS AND RESULTS Eight dogs were instrumented to measure LV pressure (micromanometer), LV volume (three sonomicrometers), and left circumflex and anterior descending coronary artery flows (ultrasonic flowmeter). Data were acquired after recovery from the surgery with the animals awake and unsedated. After administration of hexamethonium and atropine, steady-state loading conditions were changed with phenylephrine or nitroprusside in four to five steps before and during the infusion of dobutamine (6 to 10 micrograms.-1kg.-1min). MVO2 and PVA obtained under steady-state conditions were linearly correlated both before and during dobutamine. The MVO2-PVA relation obtained on a beat-to-beat basis during transient caval occlusion was less linear and not coincident with the steady-state relation. Dobutamine shifted the steady-state MVO2-PVA relation upward in all hearts, increasing the MVO2 axis intercept of the MVO2-PVA relation (P CONCLUSIONS MVO2 and PVA are linearly related during steady-state alterations in loading conditions in conscious dogs but not on a beat-by-beat basis during transient caval occlusion. Increase in contractility by dobutamine produces an upward shift of the MVO2-PVA relation.
Feline respiratory disease: What is the role of Mycoplasma species?

Practical relevance:Non-hemotropic Mycoplasma species are frequently implicated in cases of respiratory disease, and also conjunctivitis, in cats.Clinical challenges:Mycoplasma species are considered commensal bacteria of the conjunctiva and the upper respiratory tract of cats, and hence their role as a primary pathogen is difficult to determine. These organisms certainly appear to play a significant role as a secondary pathogen in the upper airways, and there is increasing evidence that in some animals they may represent a primary infection. However, mycoplasmas have not been found in the lower airways of clinically healthy cats – suggesting that, when present, they likely represent a pathologic process. Diagnostic challenges exist as well; Mycoplasma species are not typically identified via cytology due to their small size, and culture of these organisms requires special media and handling. Although PCR has improved identification and allowed for speciation, conflicting culture and PCR results can creat...
Ligand Binding Subsequent to NO Photolyses of Partially Unfolded Cytochrome c

Here we report folding studies of horse heart ferricytochrome c in the presence of NO (NO-cyt c). The midpoint concentration of guanidine hydrochloride (GuHCl) for unfolding was measured to be 2.8 M in the presence of NO and is only moderately altered relative to native cyt c under similar conditions (i.e., 2.6 M GuHCl). Recombination of NO to cyt c in the presence of 2.8 M GuHCl subsequent to photolysis is biphasic with rate constants of (4.24 ′ 0.15) x 10 3 s - 1 and 197.7 ′ 3.3 s - 1 with the fast and slow phase representing ∼60% and 40% relative amplitudes, respectively. NO rebinding to unfolded cyt c (in the presence of 4 M GuHCl) exhibits two phases with rate constants similar to those observed in the presence of 2.8 M GuHCl with the relative amplitude of the fast phase increasing to roughly 90%. These data suggest that NO rebinds to two populations of cyt c with one population containing a five coordinate heme and the other having a six-coordinate heme with bis-His axial ligation. These results suggest that the mis-ligated bis-His conformation forms rapidly during the refolding of cyt. c 3 + , although a population exists that can refold down a native pathway.
Structure of macrophage actin-binding protein molecules in solution and interacting with actin filaments

Abstract We have examined the structure of actin-binding molecules in solution and interacting with actin filaments. At physiological ionic strength, actin-binding protein has a Mr value of 540 × 103 as determined by direct and indirect hydrodynamic measurements. It is an asymmetrical dimer composed of 270 × 103 dalton subunits. Viewed in the electron microscope after negative staining or low angle shadowing, actin-binding protein molecules assume a broad range of conformations varying from closed circular structures to fully extended strands 162 nm in contour length. All configurations are apparently derived from the same structure which consists of two monomer chains connected end-to-end. The radius of gyration determined from the electron microscopic images was 21.3 nm in agreement with the value of 17.6 nm calculated from hydrodynamic assays. The average axial ratio from hydrodynamic measurements was 17:1, whereas fully extended dimer molecules in the electron microscope would have an axial ratio of 54:1. All of these observations indicate that actin-binding protein dimers are extremely flexible. The flexibility parameter λ ( Landau & Lifshits, 1958 ) for actinbinding protein is 0.18 nm−1. As determined by sedimentation, actin-binding protein binds to actin filaments with a Ka value of 2 × 106 m−1 and a capacity of one dimer to 14 actin monomers in filaments. After incubation of high concentrations (molar ratio to actin ≥ 1:10) of actin-binding protein with actin filaments, long filament bundles are visible in the electron microscope. Under these conditions, actin-binding protein molecules decorate the actin filaments in the bundles at regular 40 nm intervals or once every 15 monomers, approximately equivalent to the binding capacity measured by sedimentation. Low concentrations of actin-binding protein (molar ratio to actin ≥ 1:50) which promote the gelation of actin filaments in solution, did not detectably alter the isotropy of the actin filaments. Direct visualization of actinbinding protein molecules between actin filaments in the electron microscope showed that dimers are sufficient for crossbridging of actin filaments and that actinbinding protein dimers are bipolar, composed of monomers connected head-to-head and having actin-binding sites located on the free tails. We conclude that actin-binding protein is a dimer at physiological ionic strength. Each dimer has two actin filament binding sites and is therefore sufficient to gel actin filaments in solution. The length and flexibility of the actin-binding protein subunits render this molecule structurally suited for the crosslinking of large helical filaments into isotropic networks.
Phenomenological analogies between non-equilibrium and correlated systems

Abstract The time evolution of physical systems towards equilibrium and the relaxation of correlated systems shows interesting phenomenological analogies. Growth exponents are used to describe the evolution of the average domain size L ∼ t x in non-equilibrium systems and the autocorrelation function of correlated systems, C ( t ) ∼ e −( t / τ ) x . The energetics follow a simple relation between the collective and the microscopic activation energies E D = E A / x . Sublinear diffusive motions R 2 ∼ t 1− x ((1 − x )
Effect of intratracheally administered anticancer drugs on lung hydroxyproline content.

The systemic administration of the anticancer drug bleomycin is associated with the development of lung damage and fibrosis. Intratracheal (i.t.) instillation of bleomycin has often been employed in animal models of this lesion to more rapidly elicit lung damage. However, various drugs and chemicals are known to induce lung damage and fibrosis when given i.t. The results presented here demonstrate that, in addition to bleomycin, the i.t. instillation of dactinomycin, mitomycin c, doxorubicin, and cyclophosphamide resulted in increased lung levels of hydroxyproline, an indicator of fibrosis. In contrast, increases were not seen following i.t. doses of 5-fluorouracil or vincristine, and 1,3-bis(2-chloroethyl)-1-nitrosourea(BCNU) actually decreased lung hydroxyproline content. These findings suggest that i.t. treatments with bleomycin may produce lung damage more representative of anticancer drugs in general than the specific lesion which is produced when bleomycin is administered systemically. The mechanisms underlying i.t. drug-induced increases in lung hydroxyproline are not known, but may be related to the ability of cell-cycle-nonspecific anticancer drugs to directly damage alveolar epithelial cells.
A pseudoepidemic of Sporothrix cyanescens pneumonia occurring during renovation of a bronchoscopy suite

Sporothrix cyanescens, an uncommonly isolated mold, was cultured from biopsy tissue, bronchial washings and sputum obtained at bronchoscopy from four patients during a one-month period. These patients had undergone fiberoptic bronchoscopy to aid in the diagnosis of pneumonic infiltrates. During this period of time the bronchoscopy suite was being extensively renovated. Cultures of bronchoscopes, biopsy forceps and effluents from the bronchoscopy injection ports were negative for fungi, as were all environmental samples taken from the bronchoscopy suite. Known pulmonary pathogens were eventually isolated from two of the patients and the pneumonias resolved in all four patients. It is believed that bronchoscopy material was contaminated by dust created during modernization of the bronchoscopy suite and that the four isolates represent a unique pseudoepidemic of S. cyanescens pneumonia.
Variations in the motor potential with force exerted during voluntary arm movements in man.

Abstract Human subjects were trained to perform a simple forearm extension in a uniform way against two different conditions of force opposing movement. The subjects always knew before-hand how much force they had to exert to execute the movement precisely. The EEG was computer-averaged to identify any differences which could be attributed to the force of movement. The findings were: (1) No voltage change before the beginning of EMG activity could be detected in the averaged record except a slowly increasing negativity. (2) A surface negative-to-positive deflection which appeared after movement began had a greater amplitude in the greater force condition for all subjects. (3) The point of maximum negativity which began this deflection occurred with a constant latency with respect to the beginning of EMG activity for a given subject, but was not constantly related to movement itself. (4) The motor potential was of slightly greater amplitude on the side opposite to the moving limb. It appears that certain components of the motor potential are not associated with events directly concerned with initiating movement. They are possibly reflections of the feedback of movement-related information to the motor cortex from elsewhere in the brain.
Sodium and Magnesium Complexes with Dianionic α-Diimine Ligands

A series of sodium and magnesium complexes with α-diimine ligands, [Na2(LiPr)(Et2O)]2 (1, LiPr = [(2,6-iPr2C6H3)N(Me)C]2), [Na2(LMes)(solv)2]2 (LMes = [(2,4,6-Me3C6H3)N(Me)C]2, 2a, solv = Et2O; 2b, solv = THF), [Na4(LEt)2]n (3, LEt = [(2,6-Et2C6H3)N(Me)C]2), and [Mg(LMes)(THF)3] (4), have been synthesized by reduction of the diimine ligands with sodium or magnesium metal. Single-crystal X-ray diffraction analysis revealed that the sodium complexes have a 2:1 [Na2L] unit that aggregates to dimeric (1, 2a, 2b) or polymeric (3) structures, while the magnesium complex (4) shows a monomeric 1:1 structure. In all compounds 1−4, the ligand is doubly reduced to a dianion. The two Na+ ions in 1, 2a, 2b, and 3 show different coordination modes, one of which is chelated by the N donors of a ligand with supplementary Na−C bonds to the phenyl ring of another ligand within the [Na2L]2 dimer, while the other is bonded by the central C2N2 core of the ligand and solvent molecules (1, 2a, and 2b). Compound 3 displays a nov...
Modification of pancreatic carcinogenesis in the hamster model. 5. Effect of partial pancreatico-colostomy

Studies were conducted to evaluate the possibility of a bile reflux mechanism in the etiology of induced pancreatic cancer. N-Nitrosobis(2-oxopropyl)amine (BOP) was administered to Syrian hamsters after partial pancreatico-colostomy. Either the gastric or the splenic lobe of the pancreas was anastomosed to the transverse colon in groups 1 and 2, respectively. Group 3 were sham-operated controls and group 4 were controls without surgery. Shortly after surgery all 4 groups received a single subcutaneous BOP injection (20 mg/kg body weight) and survivors were sacrificed 46 weeks after BOP treatment. BOP-induced pancreatic tumor patterns were not altered by pancreatico-colostomy when compared with those in sham-operated controls. In all BOP-treated hamsters the number and distribution of benign and malignant lesions were similar in each individual pancreatic segment, including the anastomosed lobe (A-lobe); some hamsters developed tumors only in the A-lobe. As in other pancreatic regions, the initial hyperplasia in the A-lobe primarily affected peri- and intra-insular ductules and less frequently involved the ducts. These findings support the theory that the carcinogen is bloodborne and indicate that BOP-responsive pancreatic cells are distributed on a volume basis in distinct proportions within the pancreatic segments. As in previous experiments a higher incidence of pancreatic neoplasms was found in BOP-treated controls (those not operated upon) than in partially pancreatico-colostomized hamsters, including those with sham operations. Hyperplastic and dyplastic development of colonic mucosa around the anastomosis could be related to a local effect of carcinogen or of its metabolites, which are known to be excreted via pancreatic secretions.
Arx Polyalanine Expansion in Mice Leads to Reduced Pancreatic α-Cell Specification and Increased α-Cell Death

ARX/Arx is a homeodomain-containing transcription factor necessary for the specification and early maintenance of pancreatic endocrine α-cells. Many transcription factors important to pancreas development, including ARX/Arx, are also crucial for proper brain development. Although null mutations of ARX in human patients result in the severe neurologic syndrome XLAG (X-linked lissencephaly associated with abnormal genitalia), the most common mutation is the expansion of the first polyalanine tract of ARX, which results primarily in the clinical syndrome ISSX (infantile spasms). Mouse models of XLAG, ISSX and other human ARX mutations demonstrate a direct genotype-phenotype correlation in ARX-related neurologic disorders. Furthermore, mouse models utilizing a polyalanine tract expansion mutation have illustrated critical developmental differences between null mutations and expansion mutations in the brain, revealing context-specific defects. Although Arx is known to be required for the specification and early maintenance of pancreatic glucagon-producing α-cells, the consequences of the Arx polyalanine expansion on pancreas development remain unknown. Here we report that mice with an expansion mutation in the first polyalanine tract of Arx exhibit impaired α-cell specification and maintenance, with gradual α-cell loss due to apoptosis. This is in contrast to the re-specification of α-cells into β- and δ-cells that occurs in mice null for Arx. Overall, our analysis of an Arx polyalanine expansion mutation on pancreatic development suggests that impaired α-cell function might also occur in ISSX patients.
Cold Immobilization of Insects for Observation or Manipulation on a Stereomicroscope Stage

A small cold unit that fits on a stereomicroscope stage was developed to use in immobilizing insects. Most leafhopper and planthopper species tested showed no effect of as much as 120 min of cold immobilization with the unit.
Utility of an Empirical Method of Modeling Combined Zero Gap/Attached Electrode Membrane Chlor‐Alkali Cells

An extensive survey of the Docktor‐Ingenieur Dissertationen of Jakob Jorissen and Klaus‐R. Menschig, both originally from the Universitat Dortmund, is presented in regard to the empirical modeling of membrane chlor‐alkali cells and how it can be applied to a combined zero gap/attached porous electrode layer membrane cell. Particular emphasis is placed on Menschig's work on zero gap (ZG) and attached porous electrode layer (APEL) membrane chlor‐alkali cells, the first such research to appear in the open literature. Menschig developed various computer programs to characterize these ZG and APEL membrane chlor‐alkali cells. He characterized these cells by using the following parameters: the current density distribution over the membrane, the species concentrations on the membrane surfaces, equivalent diffusion layer thicknesses for the mesh electrodes/current collectors and attached porous electrode layers, and the electrode overpotentials and equilibrium potentials using the surface concentrations for the ZG and APEL cell configurations. He used empirical equations first presented by Jorissen for gap membrane cells combined with his own experimental observations for a cell which used Nafion™ 390, a bilayer perfluorosulfonic acid membrane, to determine values for these parameters. His empirical relations describe the dependence of the flux of OH− from catholyte to anolyte as a function of catholyte caustic concentration and the membrane potential drop as a function of catholyte caustic and anolyte salt concentrations. By using the experimental values for total cell potential, current density, and cell outlet concentrations with the empirical equations, Menschig calculated values for the characterizing parameters mentioned above. He used these values and other information (e.g., membrane and porous electrode layer conductivity) to predict the total cell potential for the ZG configuration. With prior knowledge of total cell potential and current efficiency for corresponding APEL and ZG cell configurations, membrane surface concentrations were derived and used in the prediction of total cell potential for a combined zero gap/attached electrode cell.