cssi/SciSciGPT-SciSciNet huggingface dataset:
Effects of Mutations and Truncations on the Kinetic Behavior of IIAGlc, a Phosphocarrier and Regulatory Protein of the Phosphoenolpyruvate Phosphotransferase System of Escherichia coli

Abstract IIAGlc, a component of the glucose-specific phosphoenolpyruvate:phosphotransferase system (PTS) of Escherichia coli, is important in regulating carbohydrate metabolism. In Glc uptake, the phosphotransfer sequence is: phosphoenolpyruvate → Enzyme I → HPr → IIAGlc → IICBGlc → Glc. (HPr is the first phosphocarrier protein of the PTS.) We previously reported two classes of IIAGlc mutations that substantially decrease the P-transfer rate constants to/from IIAGlc. A mutant of His75 which adjoins the active site (His90), (H75Q), was 0.5% as active as wild-type IIAGlc in the reversible P-transfer to HPr. Two possible explanations were offered for this result: (a) the imidazole ring of His75 is required for charge delocalization and (b) H75Q disrupts the hydrogen bond network: Thr73, His75, phospho-His90. The present studies directly test the H-bond network hypothesis. Thr73 was replaced by Ser, Ala, or Val to eliminate the network. Because the rate constants for phosphotransfer to/from HPr were largely unaffected, we conclude that the H-bond network hypothesis is not correct. In the second class of mutants, proteolytic truncation of seven residues of the IIAGlc N terminus caused a 20-fold reduction in phosphotransfer to membrane-bound IICBGlc from Salmonella typhimurium. Here, we report the phosphotransfer rates between two genetically constructed N-terminal truncations of IIAGlc (Δ7 and Δ16) and the proteins IICBGlc and IIBGlc (the soluble cytoplasmic domain of IICBGlc). The truncations did not significantly affect reversible P-transfer to IIBGlc but substantially decreased the rate constants to IICBGlc in E. coli and S. typhimurium membranes. The results support the hypothesis (Wang, G., Peterkofsky, A., and Clore, G. M. (2000) J. Biol. Chem. 275, 39811–39814) that the N-terminal 18-residue domain “docks” IIAGlc to the lipid bilayer of membranes containing IICBGlc.
A stochastic model for the effects of toxicants on populations

Abstract A stochastic model for the dynamics of a toxicant in the environment is proposed and analyzed. Then, a three-component model, consisting of a population density of an organism, and the concentrations of the toxicant in the organism and in the environment respectively, is considered. Estimates for the probabilities of persistence and extinction of the population are calculated.
Enhancement of cellular memory by reducing stochastic transitions

On induction of cell differentiation, distinct cell phenotypes are encoded by complex genetic networks. These networks can prevent the reversion of established phenotypes even in the presence of significant fluctuations. Here we explore the key parameters that determine the stability of cellular memory by using the yeast galactose-signalling network as a model system. This network contains multiple nested feedback loops. Of the two positive feedback loops, only the loop mediated by the cytoplasmic signal transducer Gal3p is able to generate two stable expression states with a persistent memory of previous galactose consumption states. The parallel loop mediated by the galactose transporter Gal2p only increases the expression difference between the two states. A negative feedback through the inhibitor Gal80p reduces the strength of the core positive feedback. Despite this, a constitutive increase in the Gal80p concentration tunes the system from having destabilized memory to having persistent memory. A model reveals that fluctuations are trapped more efficiently at higher Gal80p concentrations. Indeed, the rate at which single cells randomly switch back and forth between expression states was reduced. These observations provide a quantitative understanding of the stability and reversibility of cellular differentiation states.
Coupling between unconfined cylindrical explosive charges and rock

Abstract The stresses generated in Yule marble by unconfined cylindrical explosive charges were determined for various geometries of charges and various interface conditions between the explosive and the marble. A pellet technique was used in which the momentum imparted to a pellet placed on a free surface of a marble specimen gave a measure of the momentum of a portion of the shock wave normally incident to the free surface. Stress-time curves were determined by using pellets of several thicknesses. For a contact charge, the charge diameter affected the peak stress, measured within marble 2·00 in. from the charge, much more strongly than the charge length. The angle between the axis of the charge and the surface of the marble had little effect on peak stress if the contact area between the explosive and the marble was held constant. The peak stress within the marble decayed from 271,000 psi 0·50 in. from the contact charge to 15,200 psi 4·00 in. from the contact charge, the decay being slightly greater than a theoretical 1/ r decay. Partial confinement of the charge substantially increased the peak stress. The shock attenuation in a layer of dissimilar material between the explosive and the marble was found to be less for water than for marble itself and greatest for air. The attenuation rate in a layer of sand, cardboard, or foam rubber was also high, being almost equal to that of air.
Errors in the synoptic weather‐charts which cover the Greenland region

Greenland is a very large island with the outline of a human left ear. Its length in a north-south direction is about 1,600 nautical or 1,800 English miles, and its average breadth about 600 nautical or 750 English miles. Its area is comparable roughly with that part of the United States which is east of the Mississippi River. Save for this elongated outline, Greenland's model is that of an old-fashioned hunting-case watch—it is a flattened dome with increasingly steep outward slopes upon its borders. With exception of a marginal ribbon of land usually less than 50 miles in width, Greenland is blanketed by a glacier which everywhere forms its surface (see Fig. 1).
Newborn stimulation preventing over-stimulation is key for optimal growth & well-being.

When a baby is born, enormous environmental transitions occur that vastly differ from life inside their mother's womb. Health care providers are increasingly aware of a baby's heightened sensitivities to its environment-both in utero and extrauterine. As such, a hospital's atmosphere at the time of a newborn's birth and in the days following can greatly impact the health, development and well-being of the baby. Since the newborn's environment does play a significant role in developmental and behavioral outcomes, it's important for nurses to foster a post-partum environment for both mom and baby with the ultimate goals of optimal growth, development, healing, adjustment and well-being.
Environmental consequences of rapidly rising food output

Abstract Certain agricultural practices contribute to undesirable environmental changes. Some of the agricultural pollutants or practices leading to environmental disturbances are not new, but others are typically the result of modern methods and new technologies. Soil deterioration, the use of pesticides and fertilizers, the disposal of animal and processing wastes, increasing salinization, the application of substances containing heavy metals to soil or plants, and the ubiquity of disease-causing microorganisms may cause local or widespread problems that affect man, livestock, wildlife, natural communities, or the capacity of man to continue feeding himself. The need for increased food production in the tropics will probably cause additional environmental stresses in the future. Awareness of the actual or potential problems and the development of new agricultural technologies will help to avert many of the unwanted ecological alterations.
Low cost semi-autonomous sentry robot

This paper describes the planning, design, and implementation of a low cost, semi-autonomous sentry robot (Turret). The robot has an automatic nerf gun mounted on the top of an all-terrain mobile platform. The sensors used for target tracking are low cost infrared proximity sensors. The robot can be set into an autonomous sentry mode, in which it can track targets and fire at them automatically, or a controlled mode, for driving the turret to a new location. This design uses much more cost effective and readily available hardware and materials, and also provides an improved tracking mechanism.
Predictors of short-term diabetes remission after laparoscopic Roux-en-Y gastric bypass.

Purpose A remission of type 2 diabetes mellitus (T2DM) is one of the major goals of the contemporary bariatric surgery. The goal of our study is to identify predictors of short-term postoperative diabetes remission in order to facilitate preoperative patient selection.
Analysis of gain-of-function mutants of an ATP-dependent regulator of Tn7 transposition

Abstract The bacterial transposon Tn7 is distinguished by its unusal discrimination among targets, being particularly attracted to certain target DNA and actively avoiding other DNA. Tn7 transposition is mediated by the interaction of two alternative transposon-encoded target selection proteins, TnsD and TnsE, with a common core transposition machinery composed of the transposase (TnsAB) and an ATP-dependent DNA-binding protein TnsC. No transposition is observed with wild-type TnsABC. Here, we analyze the properties of two gain-of-function TnsC mutants that allow transposition in the absence of TnsD or TnsE. We find that these TnsC mutants have altered interactions with ATP and DNA that can account for their gain-of-function phenotype. We also show that TnsC is an ATPase and that it directly interacts with the TnsAB transposase. This work provides strong support to the view that TnsC and its ATP state are central to the control of Tn7 transposition.
Laser-induced iodine fluorescence technique for quantitative measurement in a nonreacting supersonic combustor

A nonintrusive optical technique, laser-induced iodine fluorescence (LIIF), is demonstrated in the quantitative study of the compressible flowfield in a steady, nonreacting supersonic combustor. Measurements of density, temperature, and velocity were made with the calibrated technique for two combustor operating conditions. Measurements were first conducted in the supersonic flow over a rearward-facing step for comparison with calculated pressure profiles. The second operating condition was staged, transverse injection behind a rearwardfacing step at an injection dynamic pressure ratio of 1.20. These experimental results demonstrate the capability of the technique for making accurate, spatially resolved measurements of gasdynamic variables in the complex supersonic flowfield. Complete data sets to be generated with this technique will be used to validate computational fluid dynamic (CFD) codes for supersonic combustor flowfields, prior to the inclusion of chemical reaction.
Interfacial structure and transformation mechanism of the μ phase in Al-3.9 Cu-0.5 Mg-0.5 Ag alloy

Abstract Conventional transmission electron microscope (TEM) contrast analyses were performed to identify interfacial defects on the {111}α/(001)μ interface of μ precipitates. These defects were found to be ledges, which exhibit a 6 α and a 2 α dislocation contrast. High-resolution transmission electron microscopy (HRTEM) was also employed to observe the faces and edges of one unit-cell thick μ precipitates at various aging temperatures. These observations showed the μ precipitates to be completely coherent with the matrix at early stages of growth. At the edges of relatively thick precipitates and for multiple unit-cell ledges, HRTEM indicated an extra (001)μ plane spaced approximately 2.6 nm apart and this is necessary to accomodate an approximately 9% misfit normal to the precipitate plate. A possible transformation mechanism from the α matrix to μ phase that provides an atomic correspondence between the two structures is proposed. Growth of the μ phase is explained in terms of four building blocks which relate the two structures crystallographically. At each growth step, the selection of a building block is dictated by the minimization of misfit strain energy. The transformation and growth models are in good qualitative agreement with the conventional and high-resolution TEM observations.
Clocks, Metabolism, and the Epigenome

Many behaviors and physiological activities in living organisms display circadian rhythms, allowing the organisms to anticipate and prepare for the diurnal changes in the living environment. In this way, metabolic processes are aligned with the periodic environmental changes and behavioral cycles, such as the sleep/wake and fasting/feeding cycles. Disturbances of this alignment significantly increase the risk of metabolic diseases. Meanwhile, the circadian clock receives signals from the environment and feedback from metabolic pathways, and adjusts its activity and function. Growing evidence connects the circadian clock with epigenomic regulators. Here we review the recent advances in understanding the crosstalk between the circadian clock and energy metabolism through epigenomic programming and transcriptional regulation.
Probing the conformation of human tRNA(3)(Lys) in solution by NMR.

Abstract Human tRNA 3 Lys acts as a primer for the reverse transcription of human immunodeficiency virus genomic RNA. To form an initiation complex with genomic RNA, tRNA 3 Lys must reorganize its secondary structure. To provide a starting point for mechanistic studies of the formation of the initiation complex, we here present solution NMR investigations of human tRNA 3 Lys . We use a straightforward set of NMR experiments to show that tRNA 3 Lys adopts a standard transfer ribonucleic acid tertiary structure in solution, and that Mg2+ is required for this folding. The results underscore the power of NMR to reveal rapidly the conformation of RNAs.
A second order impedance-based model for the resonance wavelength of a nanoegg

Modeling nanostructures using circuit components have been useful in the enhancement of the design process of nanostructures. Given the use of nanoparticles in a wide range of applications, it becomes important to establish efficient models that can capture the properties of nanoparticles efficiently and accurately. Asymmetrical nanoparticles are more complex to model due to the symmetry breaking involved in these particles. In this paper, we present an impedance model for nanoeggs, which are one of the widely used asymmetric nanoparticles. The impedance model captures the effect of asymmetry on the resonance wavelength of the particles and can be used in the design of structures based on these particles.
On the finite element analysis of non-linear vibration for cylindrical shells with high-order shear deformation theory

Abstract The development of an existing 36 degrees-of-frcedom (dof), curved, quadrilateral, thin shell element, for large displacement/rotation static analysis of shell structures, is extended for the study of non-linear vibration of a cylindrical shell. Parabolic transverse shear strains are assumed to vary through the shell thickness and vanish at the top and bottom surface. The equations of motion are based on a total Lagrangian frame of reference, and the applied dynamic loads are assumed conservative. A beta- m method, which is a generalization of Newmark's time marching integration scheme, and the Newton-Raphson iterative method, are both applied in order to numerically solve the set of non-linear equations of motion. An algorithm based on the above numerical procedures is developed. The isotropic or composite structures comprising laminates of orthotropic or multilayered anisotropic materials are considered to be elastic. Comparisons with several existing solutions demonstrate the validity and accuracy of the present development.
A comparison of the effects of radiation and inhibitors of oxidative phosphorylation on the nuclear structure of rat thymocytes.

Abstract The most striking visible consequence of irradiation of the thymocyte is the complete disappearance of nuclear structure. Since the primary metabolic effect of irradiation seems to be the inhibition of oxidative phosphorylation, we have determined and compared the nuclear changes caused by radiation with those caused by 2,4 dinitrophenol, parathyroid extract and oligomycin, all of which inhibit oxidative phosphorylation but have different effects on respiration and the uptake of inorganic phosphate. Those compounds (parathyroid extract and low concentrations of oligomycin) which inhibit oxidative phosphorylation, but do not affect phosphate uptake caused the disappearance of nuclear structure. On the other hand, 2,4 dinitrophenol which is known to inhibit both oxidative phosphorylation and phosphate uptake strongly inhibited the loss of nuclear structure in irradiated and unirradiated cell suspensions as well as in the irradiated rat. The metabolic prerequisites for nuclear structural homogenisation therefore seem to be a loss of the ability to carry out oxidative phosphorylation combined with a continuing ability to accumulate phosphate. It is suggested that the loss of nuclear structure is the result of a dissociation of histone from DNA in the chromatin granules of the nucleus and this dissociation is itself caused by accumulated inorganic phosphate.
Heterogeneity in mild cognitive impairment: Differences in neuropsychological profile and associated white matter lesion pathology

This study examined whether distinct neuropsychological profiles could be delineated in a sample with Mild Cognitive Impairment (MCI) and whether white matter lesion (WML) burden contributed to MCI group differences. A heterogeneous, clinical sample of 70 older adults diagnosed with MCI was assessed using cognitive scores, and WML was quantified using a semi-automated, volumetric approach on T2-weighted fluid-attenuated inversion recovery (FLAIR) images. Using cluster and discriminant analyses, three distinct groups (Memory/Language, Executive/Processing Speed, and Pure Memory) were empirically derived based on cognitive scores. Results also showed a dose dependent relationship of WML burden to MCI subgroup, with the Executive/Processing Speed subgroup demonstrating significantly higher levels of WML pathology when compared to the other subgroups. In addition, there was a dissociation of lesion type by the two most impaired subgroups (Memory/Language and Executive/Processing Speed) such that the Memory/Language subgroup showed higher periventricular lesion (PVL) and lower deep white matter lesion (DWML) volumes, whereas the Executive/Processing Speed demonstrated higher DWML and lower PVL volumes. Results demonstrate that distinct MCI subgroups can be empirically derived and reliably differentiated from a heterogeneous MCI sample, and that these profiles differ according to WML burden. Overall, findings suggest different underlying pathologies within MCI and contribute to our understanding of MCI subtypes.
Decoupling of Higgs from supersymmetric ϱ parameter

Abstract The one loop, large Higgs mass corrections to the ϱ parameter are calculated in a manifestly supersymmetric way, in a model with soft breaking in which Yukawa couplings are neglected. We find that the Higgs decouples from ϱ and, in a phenomenologically viable class of models, which are a subset of the above model, the ϱ parameter is independent of Higgs mass.
The regulatory status of xylazine for use in food‐producing animals in the United States

Xylazine is commonly used in veterinary medicine as a tranquillizer or adjunct to surgical anaesthesia. Although its use is approved in companion animals and certain species of deer, xylazine remains unapproved for use in food-producing animals in the United States. This paper reviews existing toxicological and residue chemistry information on xylazine in food animals, particularly cattle, and discusses the regulatory status of the drug in the US, as well as the conclusions reached by the Joint FAO/WHO Expert Committee on Food Additives in its recent evaluation of xylazine.
Congressional Enactments of Race–Gender: Toward a Theory of Raced–Gendered Institutions

Investigating reports of marginalization from Congresswomen of color, I examine legislative practices in the 103rd and 104th Congresses to illuminate dynamics that structure hierarchies on the basis of race and gender. I advance an account of racing–gendering as a political process that silences, stereotypes, enforces invisibility, excludes, and challenges the epistemic authority of Congresswomen of color. Racing–gendering constitutes a form of interested bias operating in Congress, which has important implications for understandings of the internal operations of political institutions, the policy priorities of Congresswomen of color, the substantive representation of historically underrepresented groups, and the practice of democracy in the United States.
Factors affecting denervation-like changes at the neuromuscular junction during aging

The ability to sustain synaptic transmission diminishes with aging. To determine whether this is accompanied by alterations in the structure of the synapse, end-plate architecture was examined in EDL muscles from 10- to 25-month rats. There was a significant age-related increase in end-plate area and a decrease in the number of nerve terminals per end plate. Furthermore, the percentage of end plates with ultraterminal sprouts increased dramatically with age. To compare the morphological changes associated with aging to the changes in response to denervation, EDL muscles from 10- and 25-month animals were partially denervated. Both end-plate area and ultraterminal sprouting increased, while terminal number decreased following denervation in the 10-month muscles. To determine whether the age- and denervation-associated changes were accompanied by alterations in muscle-derived nerve-outgrowth factors, in vitro assays were performed. Neurite outgrowth was quantified from embryonic motoneurons incubated with muscle extract, or grown on cryostat-cut muscle cross sections from 10- and 25-month innervated and denervated EDL muscles. Both aged and denervated muscles induced greater degrees of neurite outgrowth compared with younger innervated muscles. Innervation to the EDL was then examined, and signs of axonal degeneration were observed. It is suggested that aging is associated with alterations in the motor axon to the EDL muscle. These changes are manifest at the neuromuscular junction. In turn, the muscle responds as if it were in a state of functional denervation.
Links between Social Understanding and Early Word Learning: Challenges to Current Accounts.

If young children approached word learning with little social savvy, certain predictable patterns of error would arise in the way they interpret new words. The absence of such errors provides evidence that social understanding informs word learning even in the infancy period. We outline such evidence, and then scrutinize it with respect to four challenges. 1) Is it necessary to invoke genuine social understanding to explain infants’ word-learning successes? 2) Do infants treat social clues as criterial in their interpretation of new words? 3) Individuals suffering clear deficits in social understanding sometimes display apparently intact vocabulary acquisition: Must we then conclude that word learning can proceed without the aid of social understanding? 4) Is processing of social clues too effortful to be generally useful for everyday word learning? The first challenge is answered by the available evidence: Infants indeed capitalize on social understanding to interpret new words. Although the remaining challenges have yet to be resolved, we offer speculations that might profitably guide future investigation.
Aortic valve replacement via right minithoracotomy versus median sternotomy: a propensity score analysis.

ObjectiveThe aim of this study was to define the relative role of a right minithoracotomy (RT) versus standard median sternotomy (ST) for open aortic valve replacement (AVR).MethodsA retrospective ...
The transport of flare plasma from the Sun to the Earth

Abstract The shape of the shock front produced in the solar wind by the plasma from highly geo-effective solar events is determined. This shape is based on an analysis of data on the size of the sudden commencements of geomagnetic storms. The analysis is made using gas dynamics. It is found that the flare plasma expands on a broad front but with considerable departure from sun-centered radial symmetry. The implications of these results to theories of flare plasma production and geomagnetic storm processes are discussed.
Mechanism of crud formation in copper solvent extraction

The authors investigated the mechanism of crud formation in copper solvent extraction. It is indicated that pH value of solution and the phase ratio (O/A) are the main factors affecting crud formation in solvent extraction. The amount of crud extraction increases with aqueous pH value increase, and reduces with the increase of the phase ratio. Fe3+, Mg2+, fine air bubble and suspended particulates in leaching solution contribute to crud formation. One case is that a series of reactions of hydrolization and polymerization occurs for Fe3+, while pH>2.5, polyhydric complex or Fe-SO4 complex are formed. Then the complex-ions of FeOH2+, Fe2(OH)24+ cause poly-reaction, which is likely to lead emulsion. The study on Zeta potential indicates the repulsion between electriferous droplets in solvent extraction prevents phase coalescence, which is one of the major reasons for emulsion.
Preliminary experimental evaluation of a Doppler-aided attitude estimator for improved Doppler navigation of underwater vehicles

Doppler navigation is one of the most widely practiced navigation methods for underwater robotic vehicles, yet its accuracy is limited both by sensor calibration and by the accuracy of the vehicle's attitude measurement. This paper reports a method to improve the dynamic attitude estimation for underwater vehicles employing Doppler sonar and low-cost micro-electro-mechanical systems (MEMS) attitude and heading reference systems (AHRSs). Our approach employs three-axis velocity measurements from a Doppler velocity log (DVL) to estimate acceleration to provide corrections to the AHRS accelerometer signals that improve the dynamic estimates of vehicle roll and pitch. We report an implementation of this approach with a nonlinear complementary filter to estimate the vehicle attitude dynamically. We report the results of an in-water comparative experimental evaluation of the proposed and previously reported attitude estimation methods using low-cost MEMS AHRSs. We also report an experimental evaluation of the effect of the attitude estimation accuracy on the spatial accuracy of three-dimensional Doppler navigation of underwater vehicles.
Some Intriguing Relationships in Business Teaching Evaluations.

Abstract Our study of over 50,000 student rating forms from a wide spectrum of business classes tested relationships among student responses to questions that measure various faculty efforts and overall instructor effectiveness. The most influential faculty inputs were teaching courses at the right level and relating course material to the business world. We found significant differences across course and program types in teaching effectiveness by fairness in grading and preparedness for class. We conclude that instructors in different subjects provide different levels of faculty inputs, suggesting that different fields in business maintain different teaching values.
Growth reduction in American sycamore (Plantanus occidentalis L.) caused by PbCd interaction

Abstract Seedlings of American sycamore ( Plantanus occidentalis L.) were grown in Drummer silty clay loam soil treated with various concentrations of Pb, Cd, or Pb plus Cd. Plant growth and heavy metal content were measured at the end of 90 days. Heavy metal accumulation by plant parts increased with soil treatment levels but was much lower than values previously reported in the literature. Root growth, woody stem diameter increment, new stem growth and foliage growth were found to be synergistically affected by the PbCd treatment. Whilst treatment with Pb or Cd alone caused a reduction in photosynthesis and transpiration, the addition of Cd to Pb-treated plants did not reduce rates of photosynthesis and transpiration below that observed for plants treated with Pb alone. A method is proposed to quantitate the concept of synergism.
Nesprin-1α self-associates and binds directly to emerin and lamin A in vitro

Nesprin-1alpha is a spectrin repeat (SR)-containing, transmembrane protein of the inner nuclear membrane, and is highly expressed in muscle cells. A yeast two-hybrid screen for nesprin-1alpha-interacting proteins showed that nesprin-1alpha interacted with itself. Blot overlay experiments revealed that nesprin-1alpha's third SR binds the fifth SR. The carboxy-terminal half of nesprin-1alpha directly bound lamin A, a nuclear intermediate filament protein. Biochemical analysis demonstrated that nesprin-1alpha dimers bind directly to the nucleoplasmic domain of emerin, an inner nuclear membrane protein, with an affinity of 4 nM. Binding was optimal for full nucleoplasmic dimers of nesprin-1alpha, since nesprin fragments SR1-5 and SR5-7 bound emerin as monomers with affinities of 53 nM and 250 mM, respectively. We propose that membrane-anchored nesprin-1alpha antiparallel dimers interact with both emerin and lamin A to provide scaffolding at the inner nuclear membrane.
Some Comparisons of Methods of Fitting the Dosage Response Curve for Small Samples

Abstract In recent years there has been much discussion of the relative merits of several methods of fitting the normal integral dosage response curve. For a three-dose experiment with ten observations at each dose and for a five-dose experiment with four observations, three methods are compared with respect to their root mean square error in estimating m, σ, and β. Essentially the total population of samples is used. The main result is that the maximum likelihood method is superior to the minimum normit method in estimating m and σ, but for β the minimum normit method is superior.
A comparison of direct brush cytology and biopsy in the diagnosis of colorectal cancer

Direct brush cytology has been underutilized as compared with direct biopsy in the endoscopic diagnosis of colorectal lesions. We report on a large series of patients in whom biopsy and brush cytology were compared with each other and with the pathology of the specimen. Our results show that cytology should be used with biopsy to get maximal yield (97% accuracy), especially in areas of strictures or obstruction.
Sentence length and sentence retention in the free-learning situation

The hypothesis that sentence length is not a significant factor in sentence recall was tested and rejected. The lengths studied were 5, 7, and 9 words. All sentences were of the active-affirmative type. A structural-complexity factor was found to play no role in recall.
A critique of contemporary urge and craving research: Methodological, psychometric, and theoretical issues

Abstract Contemporary theories of drug urges assume that these states are central to the maintenance of drug administration in addicts and are responsible for the high rate of relapse frequently encountered when addicts attempt abstinence. Most urge theories share the assumption that urges and cravings are subjective states that are manifest behaviorally as concordant changes in overt behavior (e.g., drug pursuit and consumption), verbal reports of urges, and particular constellations of somatovisceral responses. Urge research has been impeded by inadequate development of questionnaires for assessing verbal report of urges, limitations of laboratory-based urge-induction procedures, selection and interpretation of relevant psychophysiological measures, and reluctance to critically examine the assumption that urges are necessary for drug use. Examples of research from the author's laboratory illustrating how these issues might be addressed are presented. In addition, a recent cognitive model ( Tiffany, 1990 ) is described that assumes that the processes that control drug use in the addict operate independently of those supporting drug urges. This approach, which draws on the strong parallels between various descriptions of automatic and nonautomatic cognitive processing and some key characteristics of drug-use behavior and drug urges, offers a distinct alternative to current models of drug urges.
Endocytic entry of HIV-1.

Abstract Enveloped viruses enter target cells by membrane fusion or endocytosis. In the latter case, fusion of the viral envelope is induced by the acidic pH of the endocytic vesicle [1]. As with most other retroviruses, entry of the human immunodeficiency virus (HIV) is thought to be exclusively by pH-independent membrane fusion after interaction of its envelope with CD4 and a chemokine co-receptor on the target cell [2,3]. Expression of CD4 on the virus-producing cell impairs the release and infectivity of HIV-1 NL4-3 particles [4–6]. In sharp contrast, we found that the infectivity of another HIV isolate, HIV-1 SF2 , was enhanced by expression of CD4 on the producer cells, which correlated with significantly increased amounts of viral proteins in the vesicular fraction of target cells. Endocytic inhibitors decreased infectivity of HIV-1 SF2 but enhanced that of HIV-1 NL4-3 . Expression of CD4 in the producer cell did not remove gp41 from HIV-1 SF2 virions. With these cells, the formation of syncytia could be induced by acidic medium. Thus, HIV-1 SF2 can enter the cytoplasm by an endocytic route after activation of gp41 by the acidic pH of endocytic vesicles. Endocytic entry might expand the range of cells that HIV could infect and should be considered in antiviral strategies against AIDS.
Phototropic Equilibrium in Phycomyces

When illuminated by two light sources, the positively phototropic sporangiophores of Phycomyces blakesleeanus come into a state of phototropic equilibrium. In this state, the sporangiophores assume an orientation determined by the light fluxes falling upon opposite sides of their light-sensitive zones. Under certain conditions, the sporangiophores show tropic oscillations about the equilibrium direction.
Gain saturation regime for laser-driven tabletop, transient Ni-like ion X-Ray lasers

We have demonstrated small signal gain saturation on several transient-gain Ni-like ion x-ray lasers by using a high-power, chirped-pulse amplification, tabletop laser. These results have been achieved at wavelengths from 139--203 \AA{} using a total of 5--7 J energy in a traveling-wave excitation scheme. Strong amplification is also observed for Ni-like Sn at 119 \AA{}. Gain of $62{\mathrm{cm}}^{\ensuremath{-}1}$ and gL product of 18 are determined on the $4d\ensuremath{\rightarrow}4p$ transition for Ni-like Pd at 147 \AA{} with an output energy of $12\ensuremath{\mu}\mathrm{J}$. A systematic evaluation of the laser driver parameters yields optimum beam divergence and small deflection angles of 2--5 mrads, in good agreement with simulations.
Cytokinesis in cells undergoing mitosis without genome replication.

Chinese hamster ovary cells can be forced to enter mitosis without prior DNA replication by treatment with hydroxyurea and caffeine. Cells treated in this way assemble a spindle that functions normally except that it does not accomplish anaphase spindle elongation (anaphase B). The chromatin detaches from the unreplicated kinetochores, which fragment, but establish microtubule attachments and migrate to the metaphase plate. Partitioning of the kinetochore fragments ensues on the normal schedule. Typical midbodies and cleavage furrows are established and daughter cells of equal size are produced. These results imply that intact chromosomes are not necessary for correct cleavage furrow placement but that kinetochores might be. Further, it is clear that cleavage furrow placement does not depend on anaphase spindle elongation.
Synergy Between Irradiation and Chlorination in Killing of Salmonella, Escherichia Coli O157:H7, and Listeria Monocytogenes

The objectives of the studies were to determine if radiation and chlorine acted in a simple additive process or if a nonadditive increase in inactivation occurred when chlorination followed γ-irradiation both in vitro and in situ. Separate studies evaluated the effects of γ-irradiation (0.2 kGy at 20 °C), chlorination (0.5 ppm for 10 min), or irradiation followed by chlorination of Salmonella, Escherichia coli O157:H7 Ent C9490, or Listeria monocytogenes cells suspended on membrane filters. Cocktails of Salmonella enterica serovars: Anatum, Infantis, Newport, and Stanley or of L. monocytogenes isolates: ATCC 7644, 15313, 43256, and 49594 (Scott A) were used. In each case, greater inactivation was observed from irradiation followed by chlorination than was predicted from the sum of the inactivation of the 2 treatments when applied separately. Inactivation of Salmonella cells was determined also with the pathogens adsorbed onto alfalfa seeds. Analysis of results of 3 sets of experiments with Salmonella adsorbed onto alfalfa seeds also led to the conclusion that the combination treatments were synergistic and produced a greater inactivation than were expected from the sums of the treatments although experiments with larger number of seeds gave less evidence of synergy. The effectiveness of both interventions against Salmonella was significantly reduced when the pathogen was on alfalfa seeds.
Cluster catalyzed chemisorption of H2 on Si(111)(1×1)

Abstract Molecular dynamics calculations were used to simulate the scattering of Ar n H 2 microclusters ( n = 1, 2, 4, 5, 7 and 12) from a rigid model Si(111)(1×1) surface. It is found that the dissociative chemisorption of H 2 on Si(111)(1×1) is enhanced for the Ar n H 2 compared to unclustered H 2 .
Corrosion of Refractory Alloys in Molten Lithium and Lithium Chloride

Abstract Several refractory materials have been considered over the years as containment material for lithium and lithium halides. Surface modified refractory metals are being extensively investigated for containment of reactive metals, radionuclides and their compounds. An overview of experimental observations and results of liquid lithium corrosion of selected engineering refractory materials are presented. The nature of the degradation and its mechanism has been explained. The influence of temperature, microstructure, stress, impurities and service time on the corrosion behavior for various refractory alloys have been discussed. Selection rules for materials of containment for liquid lithium and lithium compounds have been suggested. Recent experimental observations on the behavior of tantalum and niobium-based refractory metal alloys in a specific molten salt environment comprising LiCl/Li2O/Li/Li3N at 725°C have been included in an effort to select suitable materials for molten salt equipment. It has...
Very Late Stent Thrombosis in Coronary Bare-Metal Stent Implantation: A Case Report

Stent thrombosis is generally a fatal complication after percutaneous coronary intervention. Despite the incidence of stent thrombosis has reduced with improved techniques and drugs, stent thrombosis persists at a rate of 0.5-2% in elective cases, and up to 6% in patients with acute coronary syndromes. It almost always causes acute myocardial infarction or sudden cardiac death. While very late stent thrombosis, occurring beyond 1 year, is not uncommon with the use of drug-eluting stents, it is distinctly unusual with the use of bare-metal stents. We report a case of very late thrombosis of a bare-metal stent occurring 880 days after coronary stent implantation. (Korean Circulation J 2007;37:230-233)
The effect of chronic atypical antipsychotic drugs and haloperidol on amphetamine-induced dopamine release in vivo

Abstract The effect of chronic administration of antipsychotic drugs (21 days in drinking water followed by 3 days drug washout) on the d -amphetamine (1.0 mg/kg, s.c.)-induced increase in dopamine (DA) release in the striatum and the nucleus accumbens of awake, freely-moving rats was investigated with microdialysis. Chronic administration of haloperidol, a typical antipsychotic, (0.5 mg/kg/day), decreased basal extracellular DA release in the striatum and the nucleus accumbens but did not affect d -amphetamine-induced DA release in either region. In marked contrast, chronic administration of three atypical antipsychotic drugs: amperozide (2 mg/kg/day), clozapine (10 mg/kg/day) and melperone (2 mg/kg/day) increased basal extracellular DA and enhanced d -amphetamine-induced DA release in the striatum. In the nucleus accumbens, basal extracellular DA was decreased by chronic amperozide, unchanged by chronic clozapine and increased by chronic melperone. Most significantly, d -amphetamine-induced DA release was inhibited by chronic amperozide or clozapine, but unaffected by chronic melperone in this region. These results suggest that atypical antipsychotic drugs can alter DA release in a region specific manner. In particular, attenuation of amphetamine-like stimulation of DA release with reduced basal DA release in the nucleus accumbens could contribute to the antipsychotic action of amperozide which has a very weak affinity for D2 DA receptors.
Parathyroid hormone-related protein is a gravisensor in lung and bone cell biology

Parathyroid Hormone-related Protein (PTHrP) has been shown to be essential for the development and homeostatic regulation of lung and bone. Since both lung and bone structure and function are affected by microgravity, we hypothesized that 0 x g down-regulates PTHrP signaling. To test this hypothesis, we suspended lung and bone cells in the simulated microgravity environment of a Rotating Wall Vessel Bioreactor, which simulates microgravity, for up to 72 hours. During the first 8 hours of exposure to simulated 0 x g, PTHrP expression fell precipitously, decreasing by 80-90%; during the subsequent 64 hours, PTHrP expression remained at this newly established level of expression. PTHrP production decreased from 12 pg/ml/hour to 1 pg/ml/hour in culture medium from microgravity-exposed cells. The cells were then recultured at unit gravity for 24 hours, and PTHrP expression and production returned to normal levels. Based on these findings, we have obtained bones from rats flown in space for 2 weeks (Mission STS-58, SL-2). Analysis of PTHrP expression by femurs and tibias from these animals (n=5) revealed that PTHrP expression was 60% lower than in bones from control ground-based rats. Interestingly, there were no differences in PTHrP expression by parietal bone from space-exposed versus ground-based animals, indicating that the effect of weightlessness on PTHrP expression is due to the unweighting of weight-bearing bones. This finding is consistent with other studies of microgravity-induced osteoporosis. The loss of the PTHrP signaling mechanism may be corrected using chemical agents that up-regulate this pathway. In conclusion, PTHrP represents a stretch-sensitive paracrine signaling mechanism that may sense gravity.
The mass spectra of crown ethers: the effects of preferred secondary structures on fragmentation patterns

Abstract The 70 eV mass spectra of unsubstituted cyclic polyethers, “crown ethers”, from 12-crown-4 (12 membered ring) to 21-crown-7 (21 membered ring) are reported. These compounds exhibit very nearly identical spectra. Preferred secondary structures for these compounds from solution studies are used to explain specific unimolecular rearrangements; that is, the mass spectra of these “three dimensional molecules” is discussed.
Kisspeptin Regulates Gonadotroph and Somatotroph Function in Nonhuman Primate Pituitary via Common and Distinct Signaling Mechanisms

Kisspeptins (Kps) have emerged as key players in the control of reproductive-axis function, in which they operate as primary regulators of hypothalamic GnRH release. In addition, recent data indicate that Kps can also directly act on the pituitary to stimulate LH and GH release in primary pituitary cell culture prepared from rats, cows, and sheep. We present herein evidence that Kps (specifically Kp-10) can also stimulate LH and GH release in primary pituitary cell cultures prepared from female baboons (Papio anubis), a species that more closely models human physiology. The stimulatory effect of Kp-10 on LH and GH release was dose and time dependent and enhanced the hormonal responses to their major regulators (GnRH for LH; GHRH/ghrelin for GH) without affecting the release of other pituitary hormones (TSH, FSH, ACTH, prolactin). Use of pharmacological intracellular signaling blockers indicated Kp-10 signals through phospholipase C, protein kinase C, MAPK, and intracellular Ca2+ mobilization, but not adenylyl cyclase, protein kinase A, extracellular Ca2+ influx (through L-type channels), or nitric oxide synthase, to stimulate both LH and GH release. Interestingly, blockade of mammalian target of rapamycin or phosphoinositol 3-kinase activity fully abolished the stimulatory effect of Kp-10 on LH but not GH release. Of note, estradiol enhanced the relative LH response to Kp-10, alone or in combination with GnRH. In sum, our data are the first to provide evidence that, in a primate model, there is a functional Kp-signaling system within the pituitary, which is dynamically regulated and may contribute to the direct control of gonadotropic and somatotropic axes.
Examining Correlates of Methamphetamine and Other Drug Use in Pregnant American Indian Adolescents.

American Indian and Alaska Native (AI/AN) adolescents have high rates of pregnancy, as well as alcohol, marijuana, cocaine, and, increasingly, methamphetamine (meth) use. The progression of adolescent drug use to meth use could have devastating impacts on AI communities, particularly when youth are simultaneously at risk for teen childbearing. In order to inform future prevention efforts, this study explores correlates of meth use in a sample of pregnant AI teens, with a focus on sociodemographic, familial, and cultural factors and use of other drugs.
Mechanistic Examination of Protein Release from Polymer Nanofibers

Therapeutic proteins have emerged as a significant class of pharmaceutical agents over the past several decades. The potency, rapid elimination, and systemic side effects have prompted the need of spatiotemporally controlled release for proteins maybe more than any other active therapeutic molecules. This work examines the release of two model protein compounds, bovine serum albumin (BSA) and an anti-integrin antibody (AI), from electrospun polycaprolactone (PCL) nanofiber mats. The anti-integrin antibody was chosen as a model of antibody therapy; in particular, anti-integrin antibodies are a promising class of therapeutic molecules for cancer and angiogenic diseases. The release kinetics were studied experimentally and interpreted in the framework of a recently published theory of desorption-limited drug release from nondegrading—or very slowly degrading—fibers. The results are consistent with a protein release mechanism dominated by desorption from the polymer surface, while the polycaprolactone nanofib...
Two-stage design of multirate ℋ ∞ optimal controllers

A new methodology is presented for the design of ℋ ∞ optimal multirate controllers. A key feature of the proposed approach is the design of the slow rate part of the multirate controller via lifting and ℋ ∞ optimization. This approach addresses potential problems of aliasing due to the multirate controller by taking into consideration closed-loop performance. Our results are illustrated by a design example and compared to the resampling approach in terms of frequency response measures and closed-loop time responses. The proposed design methodology leads to multirate controllers that well approximate the ℋ ∞ closed-loop performance of an optimal fast rate design at an overall computational cost similar to multirate controllers designed by resampling.