cssi/SciSciGPT-SciSciNet huggingface dataset:
Constraining Carbon and Nutrient Flows in Soil With Ecological Stoichiometry

Soil organic matter (SOM) is central to soil carbon (C) storage and terrestrial nutrient cycling. New data have upended the traditional model of stabilization, which held that stable SOM was mostly made of undecomposed plant molecules. We now know that microbial by-products and dead cells comprise unexpectedly large amounts of stable SOM because they can become attached to mineral surfaces or physically protected within soil aggregates. SOM models have been built to incorporate the microbial to mineral stabilization of organic matter, but now face a new challenge of accurately capturing microbial productivity and metabolism. Explicitly representing stoichiometry, the relative nutrient requirements for growth and maintenance of organisms, could provide a way forward. Stoichiometry limits SOM formation and turnover in nature, but important nutrients like nitrogen (N), phosphorus (P), and sulfur (S) are often missing from the new generation of SOM models. In this synthesis, we seek to facilitate the addition of these nutrients to SOM models by (1) reviewing the stoichiometric bias—the tendency to favor one element over another—of four key processes in the new framework of SOM cycling and (2) applying this knowledge to build a stoichiometrically explicit budget of C, N, P, and S flow through the major SOM pools. By quantifying the role of stoichiometry in SOM cycling, we discover that constraining the C:N:P:S ratio of microorganisms and SOM to specific values reduces uncertainty in C and nutrient flow as effectively as using microbial C use efficiency (CUE) parameters. We find that the value of additional constraints on stoichiometry vs. CUE varies across ecosystems, depending on how precise the available data is for that ecosystem and which biogeochemical pathways are present. Moreover, because CUE summarizes many different processes, stoichiometric measurements of key soil pools are likely to be more robust when extrapolated from soil incubations to plot or biome scale estimates. Our results suggest that measuring SOM stoichiometry should be a priority for future empirical work and that the inclusion of new nutrients in SOM models may be an effective way to improve precision.
Thermo-Mechanical Characterization of Polyurea Hybrid Blend Variants

Polyurea (PU) is a microphase-segregated elastomer synthesized through bulk polymerization of isocyanates and amines. Polyurea has previously been shown to be an excellent medium in absorbing energy from blast and shock waves, especially when layered with metallic components. The focus of the present work is to evaluate the thermo-mechanical properties of polyurea considering three different hybrid blend formulations. Hybrid polyurea specimens are synthesized by reacting a blend of diamines of long and short chains (Versalink P-1000 and P-250) with weight ratios of 70:30% and 80:20%, with Isonate 143 L and compared with a previously studied blend of 76:24%. This original blend formulation has been shown to have mostly similar properties to a standard PU formulation that uses medium length chain diamines (VP-650) and the same overall hard domain proportion. However, the blend formulation shows wider transition and loss spectra. Thermal phase transition and conductivity measurements are performed to better comprehend the thermal characteristics of the proposed blend formulations. Storage and loss moduli DMA master-curves along with high strain rate data at room temperature using split Hopkinson pressure bar (SHPB) will be presented. The high strain rate experiments are conducted in unconfined and confined configurations to asses shear and bulk responses of material. The overall objective of this approach is to propose fine-tuned blend formulations that can provide a balanced stiff and tough elastomeric response.
Qualitative Study to Understand Pediatric Hospitalists and Emergency Medicine Physicians' Perspectives of Clinical Pathways.

Introduction Healthcare costs are rising, and clinical pathways (CPW) are one means to promote high-value care by standardizing care and improving outcomes without compromising cost or quality. However, providers do not always follow CPW, and our understanding of their perceptions is limited. Our objective was to examine pediatric hospital medicine (PHM) and pediatric emergency medicine (PEM) physician perspectives of CPW. Methods We conducted semistructured, in-depth, one-on-one qualitative interviews with PHM and PEM physicians between February 2017 and August 2017. Interviews were audio-recorded, professionally transcribed, and accuracy verified. Using an inductive analytic strategy, we systematically coded the data to identify themes. Results We interviewed 15 PHM and 15 PEM physicians. These providers identified many benefits and limitations of CPW, which positively or negatively impact resource utilization, communication, education of personnel, patients, and families, as well as practice behaviors and attitudes. Perceived benefits included (1) reduction of unnecessary utilization, (2) standardization of care, (3) improved communication, (4) education of oneself and others, and (5) confidence and validation when actions align with CPW. Limitations of CPW were (1) resource utilization for revisions, updates, and dissemination; (2) "tunnel vision" and cognitive biases; (3) loss of autonomy; (4) prescriptive medicine; (5) information overload; (6) pressure to adhere; and (7) guilt if actions do not align with CPW. Conclusions CPW are tools with advantages and disadvantages that are used and viewed differently by providers. Such insight into how physicians perceive CPW may help to optimize hospital improvement work and enhance high-value care.
Lithotripsy for peripheral artery disease: Encouraging immediate results…But show us the money!

Of adults, 12% have PAD, with nearly 30% older than 70 years with the disorder. With obesity, diabetes mellitus, tobacco abuse, hypercholesterolemia, and poorly controlled hypertension, the incidence of PAD continues to increase. Endovascular treatment of femoropopliteal disease has an alarmingly high rate of restenosis, even with new technology with target lesion revascularization rates at 40-60% at 1 year. Intravascular lithotripsy appears to be safe and acutely effective, but there is no long-term data on whether it has a role in effective treatment of PAD.
Chapter 8 – Movement: Search, Navigation, Migration, and Dispersal

Location is crucial in the life of an animal; in this chapter we cover the mechanisms used by animals to find food, shelter, mates, and the right microclimate. Animals may find good habitat by moving randomly, but more often movements are oriented to external stimuli. After determining the location of a stimulus, an animal moves toward that stimulus if it is attractive, or away from it if it is repulsive. Compass orientation gives animals the ability to move at an angle with respect to the location of the sun, moon, stars, or the earth’s magnetic field; homing and migration typically depend on compass orientation. In addition, path integration is important to many animals. When using path integration, an animal calculates an efficient route to its nest or den based on its outward journey. Migration allows animals to find seasonally appropriate habitats but requires complex navigation that can span thousands of kilometers.
When Neoliberalism and Patriarchy Conspire: Plastic Surgery in the South Korean Reality TV Show Let Me In

The South Korean reality TV show Let Me In uses visual storytelling conventions to situate its participants within heteronormative narrative tropes. Operating in an economy of shame that masks the ...
A preliminary risk prediction model for cannabis use disorder

Abstract The ongoing trend toward legalization of cannabis for medicinal/recreational purposes is expected to increase the prevalence of cannabis use disorder (CUD). Thus, it is imperative to be able to predict the quantitative risk of developing CUD for a cannabis user based on their personal risk factors. Yet no such model currently exists. In this study, we perform preliminary analysis toward building such a model. The data come from n = 94 regular cannabis users recruited from Albuquerque, New Mexico during 2007–2010. As the data are cross-sectional, we only consider risk factors that remain relatively stable over time. We apply statistical and machine learning classification techniques that allow n to be small relative to the number of predictors. We use predictive accuracy estimated using leave-one-out-cross-validation to evaluate model performance. The final model is a LASSO logistic regression model consisting of the following seven risk factors: age; level of enjoyment from initial cigarette smoking; total score on Impulsive Sensation-Seeking Scale questionnaire; score on cognitive instability factor of Barratt Impulsivity Scale questionnaire; and scores on neuroticism, openness, and conscientiousness personality traits of Neuroticism, Extraversion, and Openness inventory. This model has an overall accuracy of 0.66 and the area under its receiver operating characteristic curve is 0.65. In summary, a preliminary relative risk model for predicting the quantitative risk of CUD is developed. It can be employed to identify users at high risk of CUD who may be provided with early intervention.
Place-Based Inquiry in Action

This chapter offers tools and projects that can facilitate place-based learning or serve as models. The authors look at some of the technology tools that can be leveraged for reading the world, understanding how place matters, or telling stories from multiple perspectives. While the technology available for place-based learning will undoubtedly change in the coming years (and even months), it is worthwhile to at least explore types of tools to give readers a sense of what is currently available and how to think about these technologies. This is a non-exhaustive list; tools the authors had success with or tools that are gaining in popularity are included. Several place-based learning projects that support inquiry and engage learners are reviewed. The chapter concludes by discussing some of the new and emerging directions in the field.
Predicting kinetics of polymorphic transformations from structure mapping and coordination analysis

To extend materials design and discovery into the space of metastable polymorphs, rapid and reliable assessment of transformation kinetics to lower energy structures is essential. Herein we focus on diffusionless polymorphic transformations and investigate routes to assess their kinetics using solely crystallographic arguments. As part of this investigation we developed a general algorithm to map crystal structures onto each other, and ascertain the low-energy (fast-kinetics) transformation pathways between them. Pathways with minimal dissociation of chemical bonds, along which the number of bonds (in ionic systems the first-shell coordination) does not decrease below that in the end structures, are shown to always be the fast-kinetics pathways. These findings enable the rapid assessment of the kinetics of polymorphic transformation and the identification of long-lived metastable structures. The utility is demonstrated on a number of transformations including those between high-pressure ${\mathrm{SnO}}_{2}$ phases, which lack a detailed atomic-level understanding.
Safe Feedback Motion Planning: A Contraction Theory and ℒ 1 -Adaptive Control Based Approach

Autonomous robots that are capable of operating safely in the presence of imperfect model knowledge or external disturbances are vital in safety-critical applications. In this paper, we present a planner-agnostic framework to design and certify safe tubes around desired trajectories that the robot is always guaranteed to remain inside. By leveraging recent results in contraction analysis and ℒ 1 -adaptive control we synthesize an architecture that induces safe tubes for nonlinear systems with state and time-varying uncertainties. We demonstrate with a few illustrative examples1 how contraction theory-based ℒ 1 -adaptive control can be used in conjunction with traditional motion planning algorithms to obtain provably safe trajectories.
Nuove prospettive sui sintomi e simboli nel caso di Clara e il loro ruolo nel processo terapeutico

The treatment of Clara as described by Dr Marina Amore provides new insights into the role of somatic functions in the development of emotional disorders and in the therapeutic communication. According to the theory of the referential process, descriptions of specific bodily experiences may function to build connections to the symbolic and verbal mode when narratives involving people and events of life are not accessible. During the 10 years of treatment, Clara’s reports of her severe neuralgic symptoms, and her bodily as well as emotional experience in her interactions with Dr. Amore enabled her eventually to talk about past and present experiences with her parents and others, and to rebuild emotion schemas that had been dissociated. Dr. Amore’s own bodily feelings in her interactions with Clara guided her in the therapeutic work, and also opened new understanding of experiences in her own life. The referential process can be seen as playing out in depth between and within the two participants as they recognized Clara’s growth, and also worked to resolve their sense of loss in the termination phase.
A Comparative Study of Smoking Cessation Programs on Web Forum and Facebook

Without time and geographical limitations, online smoking cessation programs attract a lot of users to help them quit smoking. This study compares two online smoking cessation support groups, QuitNet Forum and QuitNet Facebook, to evaluate the influence of software features that affect communication. We collect data from posts and comments of these two communities respectively, and compare user behavior from aspects of response immediacy and social network analysis. The associations between user behavior and quit stages were investigated. It is found that users of QuitNet Forum participate in communications more actively than users of QuitNet Facebook. The user behavior of QuitNet Facebook has a wider spectrum than that of QuitNet Forum.
Linear Algebra Essentials

When elementary school students first leave the solid ground of arithmetic for the more abstract world of algebra, the first objects they encounter are generally linear expressions. Algebraically, linear equations can be solved using elementary field properties, namely the existence of additive and multiplicative inverses. Geometrically, a nonvertical line in the plane through the origin can be described completely by one number—the slope. Linear functions f:R→R enjoy other nice properties: They are (in general) invertible, and the composition of linear functions is again linear.
Incorporating Information Literacy into the Music Curriculum

Abstract Whether a music librarian' circle of influence includes only reference desk interactions or administrative decisions on curriculum development and teaching, many of ACRL' suggested guidelines from their Best Practices Initiative can be incorporated into music programs. In addition to utilizing these guidelines, ideas from existing music programs that integrate information literacy elements can be used as models for local programs. This article overviews ACRL' guidelines along with some examples from corresponding applications and practices in music programs.
Robust Pole Assignment for Computed Torque Robotic Manipulators Control

Robotic manipulator control designers often assume accurate knowledge of the system parameters. In practice, such as assumption will often lead to unacceptable deterioration in controller performance and robust approaches for the design of manipulator controllers are required. In this paper, the computed torque method is used to reduce the manipulator controller design to a linear problem. A robust pole assignment approach is used to select a suitable linear state feedback for the nominal computed torque model. The effect of modeling errors is accounted for by a state-dependent acceleration disturbance vector. Stability bounds for this acceleration vector are obtained using the Lyapunov approach and robustness measures to assess its effect are suggested. A 2-D.O.F. manipulator design example is given to demonstrate the design approach. Simulation results suggest that state feedback that recouples the state variables decoupled in the computed torque approach may offer some advantages over decoupled designs.
Integrated Fuel Processor Development

The Department of Energy's Office of Advanced Automotive Technologies has been supporting the development of fuel-flexible fuel processors at Argonne National Laboratory. These fuel processors will enable fuel cell vehicles to operate on fuels available through the existing infrastructure. The constraints of on-board space and weight require that these fuel processors be designed to be compact and lightweight, while meeting the performance targets for efficiency and gas quality needed for the fuel cell. This paper discusses the performance of a prototype fuel processor that has been designed and fabricated to operate with liquid fuels, such as gasoline, ethanol, methanol, etc. Rated for a capacity of 10 kWe (one-fifth of that needed for a car), the prototype fuel processor integrates the unit operations (vaporization, heat exchange, etc.) and processes (reforming, water-gas shift, preferential oxidation reactions, etc.) necessary to produce the hydrogen-rich gas (reformate) that will fuel the polymer electrolyte fuel cell stacks. The fuel processor work is being complemented by analytical and fundamental research. With the ultimate objective of meeting on-board fuel processor goals, these studies include: modeling fuel cell systems to identify design and operating features; evaluating alternative fuel processing options; and developing appropriate catalysts and materials. Issues and outstandingmore » challenges that need to be overcome in order to develop practical, on-board devices are discussed.« less
Longitudinal clinical evaluation of a novel antibody cocktail for detection of high-grade squamous intraepithelial lesions on cervical cytology specimens.

Abstract Context.—Although cervical cancer screening by cytology is successful, the test continues to show relatively poor operating characteristics. Cell cycle markers may enhance detection of high-grade squamous intraepithelial lesions. Objective.—To determine the clinical usefulness of ProExC, an immunocytochemical assay for cell cycle components, performed on routine cervical cytology samples. Design.—Cervical cytology samples were collected using the SurePath method. Residual cells remaining after preparation of the Papanicolaou-stained slide were used to make a second slide for ProExC staining using an indirect polymer-based immunoperoxidase method. Only adequately cellular slides were evaluated for the presence of nuclear staining within cytologically abnormal epithelial cells. Results were correlated with clinical follow-up. Results.—Six hundred twenty-four samples were satisfactorily cellular and stained. Correlation with clinical follow-up for subsequent cervical intraepithelial neoplasia 2+ on ...
Genetic Variation for Sex Ratio Traits within a Natural Population of a - Parasitic Wasp, Nasonia Vitripennis.

By analyzing isofemale strains extracted from a natural population of Nasonia vitripennis, we detected variation for the sex ratios produced in fresh hosts (first sex ratios) and in previously parasitized hosts (second sex ratios). Under simple assumptions of population structure, this between-strain heterogeneity of first sex ratios results in heterogeneity of fitnesses. There is approximately ten percent difference in average fitnesses between the strains. (The fitnesses of second sex ratios are analyzed in the accompanying paper.) Average first and average second sex ratios are uncorrelated. There is significant between-female heterogeneity within some strains for first sex ratios but not for second sex ratios. In addition, the average direct-developing and diapause first sex ratios (but not second sex ratios) are significantly correlated. There are significant correlations between the direct-developing and diapause sex ratios produced by the same female. The strains differ in their effects on the sex ratio and size of another female's brood in the same host. Data on these types of variation for sex ratio traits are essential for further progress in the study of sex ratio evolution.
The Biomechanical Effect of Posterior Cruciate Ligament Reconstruction on Knee Joint Function Kinematic Response to Simulated Muscle Loads

BackgroundThe effectiveness of posterior cruciate ligament reconstruction in restoring normal kinematics under physiologic loading is unknown.HypothesisPosterior cruciate ligament reconstruction does not restore normal knee kinematics under muscle loading.Study DesignIn vitro biomechanical study.MethodsKinematics of knees with an intact, resected, and reconstructed posterior cruciate ligament were measured by a robotic testing system under simulated muscle loads. Anteroposterior tibial translation and internal-external tibial rotation were measured at 0°, 30°, 60°, 90°, and 120° of flexion under posterior drawer loading, quadriceps muscle loading, and combined quadriceps and hamstring muscle loading.ResultsReconstruction reduced the additional posterior tibial translation caused by ligament deficiency at all flexion angles tested under posterior drawer loading. Ligament deficiency increased external rotation and posterior translation at angles higher than 60° of flexion when simulated muscle loading was a...
Association of small aromatic molecules with PAMAM dendrimers.

Many proposed applications using dendrimers, such as drug delivery and environmental remediation, involve dendrimer interactions with small molecules. Understanding the details of these interactions is important for designing dendrimers with tunable association with guest molecules. In this work, we investigate dendrimer interactions with small aromatic hydrocarbons using all-atom molecular dynamics simulations. We study the association of naphthalene (NPH)—the smallest polycyclic aromatic hydrocarbon—with 3rd–6th generation (G3–G6) polyamidoamine (PAMAM) dendrimers. Our work emphasizes that the association of small aromatic molecules with PAMAM dendrimers involves the formation of dynamic pocket-like association sites through interactions between flexible dendrimer branches and NPH molecules. The association sites are primarily formed by branches from the two outermost dendrimer subgenerations, and often involve the tertiary amine groups. Irrespective of their location on the dendrimer—whether buried or near the outer surface—these pocket-like structures lower the hydration of the associated NPH molecules. We show that on average NPH molecules with a lower hydration have a greater tendency to remain associated with the dendrimer for longer times. In general, the association sites are similar for the G3–G6 PAMAM dendrimers, indicating similarities in the association mechanisms across different dendrimer generations.
A ‘BOLD’ New Approach to Renal Oxygen Economy

The kidney is a remarkable circulatory organ. Despite contributing <0.5% of the total body mass, the kidney commands 25% of the cardiac output and exhibits the highest rates of blood flow per weight of any organ.1 The architecture and regulatory precision of the renal microcirculation dictate large differences in blood flow among the zones of the renal parenchyma. The bulk of renal blood flow is directed to the cortex to facilitate glomerular filtration and tubular reabsorption of solute and water, whereas blood flow through the hairpin loops of the medullary vasa recta is much slower to preserve osmotic gradients necessary for efficient urinary concentration.2 The vasa recta provide nutrients and oxygen to the medullary tubules, abstract metabolic waste from the tubular reabsorbate, and help to maintain medullary interstitial osmotic gradients by acting as countercurrent exchangers. The countercurrent flow of the vasa recta, coupled with the high rates of active solute transport and gradient generation by the medullary thick ascending limb of Henle (mTAL), results in a steep corticomedullary gradient of oxygen, ranging from a Po2 of ≈50 mm Hg in the cortex to ≈10 to 20 mm Hg in the medulla.3 For decades, physiologists have been intrigued with the tenuous balance of oxygen supply and demand in the relatively hypoxic renal medulla. Indeed, the extremes of this equation for the mTAL are unparalleled among mammalian tissues and place this nephron segment at high risk for hypoxic cellular dysfunction and injury.4 5 6 Numerous studies in animals have implicated imbalances in oxygen supply and demand in the pathogenesis of acute renal failure resulting from ischemic insults, radiocontrast agents, and endogenous or exogenous nephrotoxins.6 All these physiological and pathophysiological data, and the concepts they engendered, were acquired in animals. Moreover, measurements of intrarenal …
Degeneracy, as opposed to specificity, in immunotherapy

While it could be argued that Jenner, with his discovery of vaccination, ushered in the field of immunotherapy, manipulation of the human immune system to treat inflammatory diseases is only now coming of age. The mechanism behind immune specificity, the basic premise of vaccination, was largely solved with appreciation of how the MHC presents antigen, and with crystallization of the MHC/T cell receptor complex. However, as has only recently been appreciated, while a given T cell receptor may ordinarily exhibit exquisite specificity, binding to some antigenic sequences can effect a conformational change to the receptor, allowing it to recognize MHC class II/peptide complexes in a highly degenerate fashion. This capacity may represent a fundamental mechanism of autoimmune disease, since it allows microbial antigens to trigger the T cell receptors of autoreactive T cells. Indeed, as discussed below, the activation of these T cells probably occurs both indirectly, by means of the innate immune system, and directly, through T cell receptor stimulation (1). Fortunately, the T cell receptor’s degeneracy may be key to therapies, with advantages not seen with antigen-specific approaches. A recent series of publications offers new insights into how this aspect of the cellular immune response might be used to treat human autoimmune disease. One well-established but still only incompletely understood reagent that may work through such a mechanism is glatiramer acetate (GA) (Copaxone, registered trademark of Teva Pharmaceutical Industries Ltd.), discussed by Karandikar et al. in this issue of the JCI (2).
Suspended sediment sources and transport distances in the Yellowstone River basin

The activity of fallout radionuclides ( 7 Be, 1 3 7 Cs, and 2 1 0 Pb) was measured on upland and floodplain soils and on suspended sediments to quantify sources of fine sediment and to estimate sediment transport distances in stream channels in the Yellowstone River basin. Samples were collected seven times during snowmelt and runoff at nine locations from the headwaters of Soda Butte Creek to Billings, Montana, a 423-km-long reach of channel. The inventory of radionuclides in soil increases with precipitation and is highest in the headwaters. The activity of radionuclides in suspended sediment decreases downstream, and more activity is observed earlier than later in the flood hydrograph. The radionuclide activity of sediment derived from erosion of upland soils differs from that derived from bank erosion. Fine suspended sediment has an intermediate radionuclide signature that is quantified in terms of the relative contribution of these two sources of fine sediment. At sites high in the drainage, soils contribute 50% to the suspended load and this value decreases to 11%-26% downstream. Fine sediment transport distances were calculated from the exponential decrease in radionuclide concentration below a point source. Transport distances increase from a few kilometers in the headwaters to hundreds of kilometers downstream. These estimates are consistent with transport distances estimated from the settling velocity of the particles and from the distribution of mine tailings downstream from a dam failure. This study of a large watershed confirms earlier results from smaller basins and suggests that transport distances increase with basin size.
Multilamellar body formation in mammalian lung: An ultrastructural study utilizing three lipid-retention procedures. Lung multilamellar body formation

Multilamellar body formation in mammalian lung tissue was studied at an ultrastructural level utilizing three lipid retention procedures and a tannic acid containing fixative. Morphologic types of multilamellar bodies and their probable sequence of maturation are described with the lipids intact, which is probably identical to the in vivo maturation of these inclusions. Type I bodies are aggregations of multivesicular bodies that are losing their individual identities. Type II bodies have a homogeneous matrix. In Type III bodies, many paired laminations form around the periphery. Type IV bodies are 30–50% laminated. Type V bodies are 60–95% laminated. Laminations in all stages are highly osmiophilic, not stained by tannic acid, uranyl acetate or lead citrate, very concentric, apparently formed from the matrix, and in the later stages torturously fold back on themselves. Lamellar width is 35–38 A and the periodicity is 66 A. Findings are discussed in light of previous lipid-extracted reports and results are compared to recent freeze-etch findings.
Characterizing the error distribution of lidar elevation data for North Carolina

Spatial data quality is a paramount concern in all geographical information systems (GIS) applications. Existing standards and guidelines for spatial data commonly assume the positional error is normally distributed. While non-normal behaviour of the error in digital elevation data has been observed in previous research, current guidelines for digital elevation data still assume that the errors for observations in open terrain are normally distributed. This research employed an accuracy assessment dataset from a substantial lidar data collection effort, the North Carolina Floodplain Mapping Program. Strong evidence was found that the vertical error of lidar elevation data is not normally distributed and that both major and minor outliers are very common. Of the five land cover types considered, only the distribution for urban areas approximated a normal distribution, even though these observations were generally much less accurate than those for open terrain. No influence of slope on the occurrence of non-normal behaviour in the distributions was found. The RMSEz (root mean square error) statistic used to characterize the fundamental accuracy of digital elevation data was found to be very sensitive to the occurrence of outliers, questioning its use in current guidelines.
Metal-Binding Residues are Distinguished by their Lower Mobilities and Efficient Signal Propagation Properties

Metal-binding proteins are associated with a variety of functions. Understanding the fundamental functional mechanism of these proteins entails a thorough characterization of the structural and dynamic properties of their metal-binding sites. Recent studies have shown that proteins at equilibrium undergo collective changes in conformation, which facilitate their function, and such intrinsic protein dynamics can be characterized using elastic network models in conjunction with normal mode analysis methods.1 The usefulness of the Gaussian Network Model (GNM) in capturing the unique architecture-induced properties of a protein has been shown in analyzing the dynamics of catalytic sites for a series of enzymes where functional sites were inferred from structural dynamics. In this study, we analyzed the equilibrium dynamics of metal-binding proteins as seen in the lowest frequency modes predicted by the GNM, to see whether any dynamic role is assumed by the metal-binding sites, in addition to their chemical role of coordinating the ligand. We also examined the communication properties of these sites using an information theoretic spectral method of signal propagation.2 Our results demonstrate that metal-binding residues are predisposed towards having relatively smaller-scale fluctuations than other residues. Intuitively, a flexible residue would be entropically more unfavorable for binding purposes and the inherent small-scale fluctuations imply lesser loss of conformational entropy upon metal binding. Our study further shows that metal-binding residues efficiently communicate signals, suggesting that their particular locations in the structure have been evolutionarily optimized to achieve most efficient allosteric function. These properties provide insights into the functional design of metal-binding proteins.References:1. Bahar, I., Chennubhotla, C. & Tobi, D. (2007) Curr Opin Struct Biol17, 633-640.2. Chennubhotla, C & Bahar, I. (2007) PLoS Comp Biology3, 1716-26.
The conserved Pkh–Ypk kinase cascade is required for endocytosis in yeast

Internalization of activated signaling receptors by endocytosis is one way cells downregulate extracellular signals. Like many signaling receptors, the yeast α-factor pheromone receptor is downregulated by hyperphosphorylation, ubiquitination, and subsequent internalization and degradation in the lysosome-like vacuole. In a screen to detect proteins involved in ubiquitin-dependent receptor internalization, we identified the sphingoid base–regulated serine–threonine kinase Ypk1. Ypk1 is a homologue of the mammalian serum– and glucocorticoid-induced kinase, SGK, which can substitute for Ypk1 function in yeast. The kinase activity of Ypk1 is required for receptor endocytosis because mutations in two residues important for its catalytic activity cause a severe defect in α-factor internalization. Ypk1 is required for both receptor-mediated and fluid-phase endocytosis, and is not necessary for receptor phosphorylation or ubiquitination. Ypk1 itself is phosphorylated by Pkh kinases, homologues of mammalian PDK1. The threonine in Ypk1 that is phosphorylated by Pkh1 is required for efficient endocytosis, and pkh mutant cells are defective in α-factor internalization and fluid-phase endocytosis. These observations demonstrate that Ypk1 acts downstream of the Pkh kinases to control endocytosis by phosphorylating components of the endocytic machinery.
Formation in Vitro of Hybrid Dimers of H463F and Y74F Mutant Escherichia coli Tryptophan Indole-lyase Rescues Activity with l-Tryptophan†

Y74F and H463F mutant forms of Escherichia coli tryptophan indole-lyase (Trpase) have been prepared. These mutant proteins have very low activity with L-Trp as substrate (k c a t and k c a t /K m values less than 0.1% of wild-type Trpase). In contrast, these mutant enzymes exhibit much higher activity with S-(o-nitrophenyl)-L-cysteine and S-ethyl-L-cysteine (k c a t /K m values about 1-50% of wild-type Trpase). Thus, Tyr-74 and His-463 are important for the substrate specificity of Trpase for L-Trp. H463F Trpase is not inhibited by a potent inhibitor of wild-type Trpase, oxindolyl-L-alanine, and does not exhibit the pK a of 6.0 seen in previous pH dependence studies [Kiick, D. M., and Phillips, R. S. (1988) Biochemistry 27, 7333]. These results suggest that His-463 may be the catalytic base with a pK a of 6.0 and Tyr-74 may be a general acid catalyst for the elimination step, as we found previously with tyrosine phenol-lyase [Chen, H., Demidkina, T. V., and Phillips, R. S. (1995) Biochemistry 34, 12776]. H463F Trpase reacts with L-Trp and S-ethyl-L-cysteine in rapid-scanning stopped-flow experiments to form equilibrating mixtures of external aldimine and quinonoid intermediates, similar to those observed with wild-type Trpase. In contrast to the results with wild-type Trpase, the addition of benzimidazole to reactions of H463F Trpase with L-Trp does not result in the formation of an aminoacrylate intermediate. However, addition of benzimidazole with S-ethyl-L-cysteine results in the formation of an aminoacrylate intermediate, with λ m a x at 345 nm, as was seen previously with wild-type Trpase [Phillips, R. S. (1991) Biochemistry 30, 5927]. This suggests that His-463 plays a specific role in the elimination step of the reaction of L-Trp. Refolding of equimolar mixtures of H463F and Y74F Trpase after unfolding in 4 M guanidine hydrochloride results in a dramatic increase in activity with L-Trp, indicating the formation of a hybrid H463F/Y74F dimer with one normal active site.
Using zip code-level mortality data as a local health status indicator in Mobile, Alabama.

ABSTRACT Objective Having local health data is critical to combat health disparities, and zip code-level data are an underutilized source of such information. We sought to use zip code-level mortality data to determine where health disparities existed in our local area. Methods The most heavily populated zip codes were aggregated into 2 groups: (1) study area population (SAP) where ≥20% of individuals lived in poverty in 1999; (2) comparison area population, Results The SAP had higher percentages of African Americans and women and much lower levels of income, employment, and education. Some zip codes in SAP had over 40% living below the poverty level. The RR of death from all but 4 of the 22 causes examined was ≥40% higher in the SAP. Major disparities (RR >2.5) were seen for human immunodeficiency virus, homicide, hypertensive heart and renal disease, and kidney disease. Actual death rates were highest for major cardiovascular disease and cancer, and the level of disparities here (RR ∼ 1.4) make them important areas for concentration. Conclusion Using zip code-level data provides an accurate foundation from which to design local interventions to address health disparities.
Positive End Expiratory Pressure (PEEP) and Right to Left Shunting in Immature Goats

Immature fetal goats were exteriorized by caesarean section and catheters were placed in a pulmonary vein (PV), carotid artery (CA), femoral artery (FA), and the main pulmonary artery (PA). The goats were ventilated at 7.5 and 15 cm H20 positive end expiratory pressure (PEEP) between control periods at 0 PEEP. Right to left shunting (Qs/Qt) was calculated for three anatomic sites: lung, foramen ovale, and ductus arteriosus, and for two summation shunts: preductal and total. Total Qs/Qt increased in 8 of 14 animals at 7.5 cm H2O PEEP and in 7 of 12 animals at 15 cm H2O PEEP. Intrapulmonary shunting increased in only one experiment. The increase in total Qs/Qt resulted from elevated extrapulmonary shunting, always including the ductus arteriosus. The variation in response to PEEP was from animal to animal and not from one level to another within one animal. Changes in total Qs/Qt on PEEP did not correlate with the size of control Qs/Qt at any site.
The calm before the storm? Burnout and compassion fatigue among undergraduate nursing students

Studies have consistently highlighted the deleterious impact of burnout and compassion fatigue on professional nurses' well-being and willingness to remain in the profession. Yet, as to what extent these noxious conditions are suffered among nursing students is still unclear. In this study 436 undergraduate nursing students completed surveys assessing their experiences of emotional exhaustion, depersonalization, lack of personal accomplishment, burnout, secondary traumatic stress, and compassion satisfaction (factors of burnout and compassion fatigue). There were no significant differences found between 3rd and 4th year students' reports of detrimental conditions and those of the 1st or 2nd year students. Furthermore, 4th year students reported significantly higher levels of personal accomplishment compared to 1st and 2nd year students. Semi-structured in-depth interviews with 3rd and 4th year students revealed that their clinical exposure during these years (especially during the 4th year) may enhance their other-orientation as well as promote role actualization, which may serve as protective features. Students did, however, express concern regarding an inevitable onset of burnout at some point during their professional careers. It is suggested that a key to understanding the onset and experience of burnout and compassion fatigue among nurses is to continue to examine the transition from student to professional nurse and the cultural atmosphere of nursing education compared to professional practice.
Electron microscopic study of epidermal prickle cells.

The introduction of the electron microscope by Knoll and Ruska (1) in 1931 has led to the development of new technics for the examination of biological material with this instrument. The preparation of very thin tissue sections of the thickness of 34 o micron and thinner has been one such recent development.
Fibrates in Combination With Statins in the Management of Dyslipidemia

While elevated low-density lipoprotein cholesterol is the primary target of hypercholesterolemia treatment, high triglycerides and low high-density lipoprotein cholesterol are also important targets for therapy. Correcting these lipid abnormalities should be an integral part of therapy in hypertensive individuals. Medications such as the fibrates are effective and well tolerated for reducing triglycerides and increasing high-density lipoprotein cholesterol, and their use has resulted in a reduction in cardiovascular events. Fibrates are also recommended as adjunct therapy for patients receiving statins whose low-density lipoprotein cholesterol or non-high-density lipoprotein cholesterol is not reduced to goal levels. The combination of a statin and a fibrate may, however, raise the risk of myopathy and rhabdomyolysis. Gemfibrozil, one of the fibrates, but not fenofibrate, interferes with statin glucuronidation, which may increase the risk of myopathy due to elevations in statin serum levels. This may at least partially explain the lower incidence of myopathy with fenofibrate compared with gemfibrozil when combined with statins. Combination therapy with a fibrate and a statin is a potentially useful therapy for patients with atherogenic lipid profiles, for which fenofibrate appears to be a more appropriate choice due to less myopathic potential.
Measure for measure? Commensuration, commodification, and metrology in emissions markets and beyond

The proliferation of markets and market-based policy instruments in environmental governance is premised on the establishment of metrological regimes and the practices of measurement, commensuratio...
When patients first suspect and find out they are infected with the human immunodeficiency virus: Implications for prevention

Abstract To evaluate how individuals infected with the human immunodeficiency virus (HIV) became aware of their infection, when they first suspected they were infected with HIV and factors associated with suspecting HIV infection, we surveyed 227 patients at an urban outpatient HIV clinic. Though nearly all patients acknowledged risk factors for HIV, 60% reported that they did not suspect that they were infected until they received a positive HIV antibody test result. Non-white patients were less likely to suspect HIV infection prior to testing than white subjects (p < 0.03). Subjects not suspecting infection more often received HIV testing through a screening program or during a medical encounter (p = 0.02) and were less likely to be told by others that they might be infected (p = 0.001) than patients suspecting infection prior to testing. Forty-eight percent of subjects who suspected HIV infection prior to testing waited one year or more before obtaining their HIV antibody test. Interventions to reduce ...
Experiences with Pulsus Alternans: Ventricular Alternation and the Stage of Heart Failure

Three years' experience with pulsus alternans, including its production with exercise, has shown that alternans may exhibit at least 3 types of behavior, and has led the authors to believe that the type of behavior a patient presents is related to the degree of heart failure present. Those patients who developed alternans following exercise were not in cardiac failure clinically, and yet hemodynamic data indicated myocardial insufficiency. A sustained pulsus alternans at rest seems to have no special prognostic significance in heart failure.
Evaluation of Several Polymer Materials for Use as Solid Lubricants in Space

The tribological properties of ten different polymer-based materials were evaluated in a vacuum environment to determine their suitability for possible lubrication applications in a space environment, such as might be encountered on the proposed space station. A pin-on-disk tribometer was used and the polymer materials were evaluated either as solid body disks or as films applied to 440C HT stainless steel disks. A 440C HT stainless steel hemispherically tipped pin was slid against the polymer materials. For comparison, similar tests were conducted in a controlled air atmosphere of 50 percent relative humidity air. In most instance, the polymer materials lubricated much better under vacuum conditions than in air. Thus, several of the materials show promise as lubricants for vacuum applications. Friction coefficients of 0.05 or less and polymer material wear rates of up to 2 orders of magnitude less than found in air were obtained. One material showed considerable promise as a traction drive material. Rela...
The influence of relationship quality on the innovation capacity in traditional food chains

Purpose – Relational aspects between actors in a chain have been found to influence innovation capacity. Yet, many studies focus rather on groups of chain members, without investigating personalized links between the chain members. Other research involved case‐studies on a limited number of individual chains. The purpose of this paper is to examine quantitatively how the perceived relationship quality among three relational linked chain members affects the innovation capacity in traditional food chains beyond the dyad.Design/methodology/approach – Evidence is drawn from a survey of 90 triplets of firms (three interlinked chain members), with each triplet belonging to a single individual traditional food chain. Research was conducted in three European countries and six traditional food product categories. Heterogeneity across these chains is examined based on cluster analysis. Binary logistic regression is used to examine the influence of relationship quality on the innovation capacity in the chains.Findin...
Hypoxia-inducible regulation of a prodrug-activating enzyme for tumor-specific gene therapy.

Previous studies have suggested that tumor hypoxia could be exploited for cancer gene therapy. Using hypoxia-responsive elements derived from the human vascular endothelial growth factor gene, we have generated vectors expressing a bacterial nitroreductase (NTR) gene that can activate the anticancer prodrug CB1954. Stable transfectants of human HT1080 tumor cells with hypoxia-inducible vectors were established with G418 selection. Hypoxic induction of NTR protein correlated with increased sensitivity to in vitro exposure of HT 1080 cells to the prodrug. Growth delay assays were performed with established tumor xenografts derived from the same cells to detect the in vivo efficacy of CB1954 conversion to its cytotoxic form. Significant antitumor effects were achieved with intraperitoneal injections of CB1954 both in tumors that express NTR constitutively or with a hypoxia-inducible promoter. In addition, respiration of 10% O2 increased tumor hypoxia in vivo and enhanced the antitumor effects. Taken together, these results demonstrate that hypoxia-inducible vectors may be useful for tumor-selective gene therapy, although the problem of delivery of the vector to the tumors, particularly to the hypoxic cells in the tumors, is not addressed by these studies.