cssi/SciSciGPT-SciSciNet huggingface dataset:
A Structure Based Course-Graining Physical Modeling of the Voltage Activated Kv1.2 Channel - Simulating and Analyzing the Fast Gating Current

K+ ion (Kv) channels catalyze ion permeation across membrane in a voltage dependent way, regulating electrical activities in cells. Several functional and structural studies demonstrate that Kv has a voltage sensor domain (VSD) that is coupled to changes in the membrane potential. An increase in the membrane potential activates the VSD, which drives the gate domain to open, generating voltage dependent ionic currents. There have been intense studies of the mechanism of the activation of Kv channels, using the kinetic models built from electrophysiological measurements. Recent structural studies also offered a detailed structural mechanism (with a phenomenological free energy landscape), suggesting how the movements of the conserved ARG residues in the VSD, upon changes in the membrane potential, can be facilitated. Starting with structural models of the voltage activation of the K1.2 channel and using our coarse-graining (CG) model allowed us to simulate the response of the channel to voltage changes. The simulations allowed us to evaluate the gating charge in terms of the change in the simulated electrolytes distribution. The change in gating charge was then converted to gating current using our renormalization model and the resulting time dependent of the protein fluctuation. The CG free energy landscapes allowed us to simulate the slow component of the gating current for the activation processes. Most significantly, our unique ability to simulate the time dependence of the fast gating current reproduces the observed trend, thereby providing a detailed picture of its molecular origin.
Knots and statistical mechanics

Abstract This paper gives a self-contained exposition of the background and context for quantum invariants of knots and links as state summations.
Bena Bena Political Organization

Abstract Focusing on the Korofeigu ‘district’ of the Numuyagabo ‘tribe’ in Bena Bena census division, this paper considers the appropriateness of terms used to designate units of New Guinea Highlands social structure. Some terms have a certain utility, but not for understanding Korofeigu political organization—taking ‘political’ as referring primarily to public affairs. Marriage and warfare were not directly linked, and districts and clans rarely acted as single groups or polities. The key figures are Big Men whose status rested on ability in warfare. War relations were power relations with no notion of fair play and no opposition of balanced groups. A group's survival rested on the success of its Big Men in organizing and extending their personal networks, and on the balancing of competition and individual ambition between them in a complex interplay of security circles—the significant polities in political action.
Solving nonstationary infinite horizon stochastic production planning problems

Forecast horizons are defined as long enough planning horizons that ensure agreement of first period optimal production decisions of finite and infinite horizon problems regardless of changes in future demand. In this paper, we prove forecast horizon existence and provide computational procedures for production planning problems that satisfy the following monotonicity property: for any fixed finite planning horizon, there exist first period optimal solutions that are monotone with respect to monotone changes in stochastic demand.
Summarizing the First Ten Years of NASA's Aqua Mission

The Aqua spacecraft was launched on May 4, 2002 with six Earth-observing instruments on board to collect data on a wide variety of Earth system variables. After ten years of on-orbit operations, Aqua has provided data that have contributed to over 2000 scientific publications, with new results on the Earth's energy budget, trace gases and particulate matter in the atmosphere, vegetation on land and in the oceans, and many aspects of the water cycle, including evaporation and transpiration, water vapor, cloud cover, precipitation, the oceans, sea ice and land ice, snow cover, and soil moisture. Additionally, Aqua data have been used to assist in practical applications ranging from weather forecasting to the deployment of firefighters and the routing of aircraft. Although the six-year design life of the satellite has been successfully completed and exceeded, enough fuel remains on Aqua for approximately another ten years of operations.
Synthesis and purification of 14C N‐2‐hydroxyethyl‐N‐nitrosourea

14C N-2-hydroxyethyl-N-nitrosourea was prepared at a specific activity of 30 mCi/mmol and 1.29 mCi/mmol by a two-step synthetic sequence using 14C ethanolamine as the labelled precursor. Its purification was performed by HPLC using a Lichrosorb-DIOL column eluted by ethyl ether. The overall radiochemical yield was 10%.
Wall shear stress on ruptured and unruptured intracranial aneurysms at the internal carotid artery.

BACKGROUND AND PURPOSE: Hemodynamics is often recognized as one of the major factors in aneurysm rupture. Flow impingement, greater pressure, and abnormal wall shear stress are all indications for aneurysm rupture. Characterizing wall shear stress for intracranial aneurysms at similar anatomic locations may help in understanding its role. MATERIALS AND METHODS: Twenty-six intracranial aneurysms at the paraclinoid and superclinoid segments of the internal carotid artery from 25 patients between July 2006 and July 2007 were studied retrospectively. Among them, 8 aneurysms were ruptured and 18 were unruptured. Computational fluid dynamics was used to determine the wall shear distribution. Morphologic and hemodynamic variables was analyzed by using the Mann-Whitney rank sum test. RESULTS: Wall shear stress was qualitatively the same throughout the cardiac cycle; thus, only wall shear stress at the end of diastole was compared. Both ruptured and unruptured aneurysms have similar maximal wall shear stress (26 versus 23 N/m2), and mean wall shear stress is shown to be a function of the aneurysm area. Ruptured aneurysms also have a greater portion of aneurysm under low wall shear stress (27% versus 11% for unruptured aneurysms, P = .03). CONCLUSION: For intracranial aneurysms at the internal carotid artery, an area of low wall shear is associated with aneurysm rupture.
Nature of large Ti 4 Cu 2 O particles formed during annealing of Cu 55 Ti 45 metallic glass ribbons

Large particles observed in annealed Cu55Ti45 metallic glass ribbons have been identified using convergent beam electron diffraction and energy dispersive X-ray spectroscopy as Ti4Cu2O (diamond cubic, space group Fd3m), consistent with the structure derived earlier by Mueller and Knott (Trans. AIME, 1963, vol. 227, p. 674) using different experimental techniques. In addition, evidence is presented which suggests that these particles form prior to and independent of either of the two binary equilibrium phases, TiCu and Ti3Cu4, which also form during the crystallization annealing treatment.
Digestion of plant tissue for analysis by ICP emission spectroscopy

Abstract A method of digesting plant tissue samples for multi‐element analysis by inductively‐coupled plasma (ICP) emission spectroscopy was developed which does not require the use of HclO4. A substitute oxidant, H2O2, eliminated the hazards associated with hot, concentrated HClO4. Optimal conditions for pre‐digestion and digestion were investigated. The procedure adopted consists of a pre‐digestion in concentrated HNO3 from room temperature to 60°C in 30 min followed by digestion at 90°C for 90 min with the addition of 30% H2O2 Analysis of NBS standard tissue samples by the proposed method gave results in good agreement with analysis following digestion in HNO3,‐HClO4 and with certified values, except for Fe.
Measuring the Quantity and Activity of Mitochondrial Electron Transport Chain Complexes in Tissues of Central Nervous System Using Blue Native Polyacrylamide Gel Electrophoresis

Mitochondrial dysfunction and degeneration are associated with many neurodegenerative disorders. A dysfunctional mitochondrial electron transport chain (ETC) impairs ATP production and accelerates the generation of free radicals. To evaluate mitochondrial function, reliable methods are needed. Conventional spectrophotometric assays may not eliminate interference from nonspecific enzyme activities and do not measure quantities of specific ETC complexes. Blue native polyacrylamide gel electrophoresis (BN-PAGE) has been used to resolve mitochondrial ETC complexes. Combined with histochemical staining, it has also been applied to measure ETC enzyme activities in muscles. The current study is to determine (1) whether BN-PAGE can be used to detect ETC complexes from different regions of the central nervous system (CNS) and (2) the quantitative range of BN-PAGE in measuring the amounts and activities of different ETC complexes. By systematically varying the protein amount and the time of histochemical reactions, we have found linear ranges comparable to spectrophotometric assays for measuring enzyme activities of several ETC complexes. In addition, we found linear ranges for measuring protein quantities in several ETC complexes. These results demonstrate that BN-PAGE can be used to measure the amount and activity of the ETC enzymes from the nerve tissues and, thus, can be applied to evaluate the functional changes of mitochondria in neurodegenerative disorders.
Initial results from a dynamic coupled magnetosphere-ionosphere-ring current model

[1] In this paper we describe a coupled model of Earth's magnetosphere that consists of the Lyon-Fedder-Mobarry (LFM) global magnetohydrodynamics (MHD) simulation, the MIX ionosphere solver and the Rice Convection Model (RCM) and report some results using idealized inputs and model parameters. The algorithmic and physical components of the model are described, including the transfer of magnetic field information and plasma boundary conditions to the RCM and the return of ring current plasma properties to the LFM. Crucial aspects of the coupling include the restriction of RCM to regions where field-line averaged plasma-β≤ 1, the use of a plasmasphere model, and the MIX ionosphere model. Compared to stand-alone MHD, the coupled model produces a substantial increase in ring current pressure and reduction of the magnetic field near the Earth. In the ionosphere, stronger region-1 and region-2 Birkeland currents are seen in the coupled model but with no significant change in the cross polar cap potential drop, while the region-2 currents shielded the low-latitude convection potential. In addition, oscillations in the magnetic field are produced at geosynchronous orbit with the coupled code. The diagnostics of entropy and mass content indicate that these oscillations are associated with low-entropy flow channels moving in from the tail and may be related to bursty bulk flows and bubbles seen in observations. As with most complex numerical models, there is the ongoing challenge of untangling numerical artifacts and physics, and we find that while there is still much room for improvement, the results presented here are encouraging.
Centrifugal-barrier effects in resonance partial decay widths, shapes, and production amplitudes

(1) We review the experimental status of identifiable centrifugal-barrier effects in: (i) shapes of resonances, (ii) accounting for deviations in SU(2) and SU(3) predictions for ratios between partial decay widths, and (iii) accounting for the dependence on spin of the elastic widths of resonances lying on the same Regge trajectory. (2) We present a contour plot from which the "kinematic partial width" (centrifugal-barrier penetration factor times two-body phase space) of any resonance into any decay channel may be obtained immediately, given the orbital angular momentum, semiclassical impact parameter, and an assumed strong-interaction radius. Using this technique we display, as an example, the kinematically preferred decays of the high-spin mesons on the leading meson trajectory (assumed linear). (3) We obtain an approximate lower bound on the strong-interaction radius on the basis of general considerations. (4) We show that, for high-spin resonances, it can be expected that the mass enhancements in different decay channels associated with these resonances may be shifted by a half-width or so with respect to each other, because of different centrifugal-barrier effects in the different channels. (5) We also show that production cross sections of high-spin particles on leading linear trajectories by either formation or peripheral processes will be substantially suppressed by centrifugal-barrier effects. (6) Finally, we observe that the production cross sections and decay widths of mesons on the leading trajectory of the Veneziano model can be understood almost entirely on the basis of kinematical considerations if the radius of the region in which the decay particles interact strongly grows linearly with the mass of the decaying resonance.
Parathyroid hormone and arterial dysfunction in the multi-ethnic study of atherosclerosis.

SummaryObjective High circulating concentrations of parathyroid hormone (PTH) have been associated with increased risks of hypertension, left ventricular hypertrophy, congestive heart failure and cardiovascular mortality. Impaired arterial function is a potential mechanism for these associations. We tested whether serum PTH concentration is associated with measures of arterial function. Design Cross-sectional study. Participants A total of 6545 persons without clinical cardiovascular disease participating in the community-based Multi-Ethnic Study of Atherosclerosis. Measurements Brachial artery flow-mediated dilation (FMD) as well as aortic pulse pressure and arterial pulse parameters derived from Windkessel modelling of the radial pressure waveform. Results Higher serum PTH concentration was associated with lower brachial artery FMD (mean difference −0·09% per 10 pg/ml PTH), higher aortic pulse pressure (0·53 mmHg per 10 pg/ml) and reduced Windkessel capacitive index C1 (large artery elasticity, −0·12 ml/mmHg × 10 per 10 pg/ml), adjusting for potential confounding variables (all P-values ≤ 0·001). These relationships were independent of serum calcium concentration, serum 25-hydroxyvitamin D concentration and estimated glomerular filtration rate and were consistent across relevant participant subgroups. Associations of PTH with aortic pulse pressure and capacitive index C1 were attenuated after adjustment for blood pressure. Serum PTH concentration was not associated with the oscillatory index C2 (small artery elasticity). Conclusions Higher serum PTH concentration was associated with impaired endothelial function, increased aortic pulse pressure and decreased capacitive index C1 in a large, diverse, community-based population. These relationships may help explain previously observed associations of elevated PTH with cardiovascular disease.
Pathogenicity of a non-haemolytic group B Streptococcus sp. in gulf killifish (Fundulus grandis Baird and Girard)

Abstract Gulf killifish ( Fundulus grandis ) were injected intraperitoneally with different bacterial concentrations and the LD 50 were 1.4 × 10 4 at 96 h and 7.5 × 10 at 168 h. No deaths occurred among fish dipped in the bacterial suspension for different time periods or when the fish were exposed to a 50 parts per thousand hyperosmotic solution prior to dip. Fish became infected when they were injured prior to dipping in the bacterial suspension, but crowding and low oxygen concentration did not precipitate infection. No deaths occurred with oral administration of the bacteria. Bacterial count per gram of tissue was determined for both liver and spleen of infected fish at four, 24-h intervals. There was a significant difference ( P > 0.12) between the bacterial counts at the different time periods.
A longitudinal evaluation of an educational software program: a case study of Urinalysis-Tutor.

Purpose. To examine students' learning before and after revising an educational software program and to explore students' patterns of use of an interactive feature that compares images. Method. Study participants were 466 University of Washington School of Medicine students. Two cohorts of students (one in 1996 and one in 1997) used the original version of the software. Following analysis of the students' learning, the software program was modified based on instructional design principles pertaining to visual learning and concept acquisition. A 1998 cohort of students used the revised program and their performance was compared with that of the 1996 cohort. Analyses were based on pre- and post-test scores, data collected from the observation of students, and navigational pathways tracked by the program. Results. There was very little difference in the overall performances of the students who used the original program and those who used the revised program. Error analysis focusing on 11 conceptual areas showed that reductions in errors occurred for six of 11 concepts, with statistically significant reductions of errors for two concepts. Additional navigational data collected in 1998 showed that students used an interactive feature for comparing images in different patterns. The data showed a positive association between performance and the anchored viewing mode of image display. Conclusions. While this study cannot point to specific design components that facilitated or hindered learning, it demonstrated a potential benefit of linking usage-pattern data and performance. Future studies should evaluate design factors that affect usage patterns and performances based on navigational data collected while students interact with software programs.
A preliminary investigation of the pseudo-spectral method numerical solution of the Perkins instability equations in the homogeneous TEC case

Abstract A pseudo-spectral method code is developed to simulate the electrodynamic instability (spread-F) behavior of the mid-latitude ionosphere by numerically solving two of the Perkins (J. Geophys. Res. 78 (1973) 218) equations. This work follows that of Miller (On gravity waves and the electrodynamics of the mid-latitude ionosphere, Ph.D. Thesis, Cornell University, 1996) and provides extensions in both the solution method—resulting in more precise, efficient and robust solutions—and in the range of solutions investigated. In the linear instability-development stage, the simulation result is consistent with the Perkins (1973) predictions, yielding relative differences of less than 0.6%. A random initial condition case like that of Miller (1996) is carried out with the result agreeing with Miller's result obtained in a different manner. In addition, the effect of non-linearity of the equation system is observed. The range of initial conditions investigated indicates that over a large wavelength range, self-similar ionospheric instability structures (Geophys. Res. Lett. 28 (2001) 4167) can be generated in conductivity and potential (the field-line integrated electron concentration is constant). Further, by using dual-wave-mode excitation with suitable parameters, saturation of the instability process is observed. Some dual-mode excitation processes are very different from the single-mode excitation case in many respects—especially in wavelength dependence. The turbulent saturation is observed in simulation to be caused by the E×B instability that requires a sharp conductivity gradient at the backside of the drift movement. On the other hand, other dual-mode excitation processes do not display a saturation state. In this case, the process converges to and then follows the path of the corresponding single-mode excitation example.
Indicators of atrial fibrillation risk in cardiac surgery patients on prophylactic amiodarone.

Abstract Background Atrial fibrillation is a common complication of cardiothoracic surgery (coronary artery bypass graft surgery or cardiac valve repair or replacement). Although predictors of postoperative atrial fibrillation have been explored in patients not receiving prophylactic antiarrhythmic therapy, independent predictors of postoperative atrial fibrillation in patients receiving prophylactic amiodarone have not been elucidated. Methods This was a substudy of a clinical trial evaluating the efficacy of an amiodarone regimen or an atrial-septal pacing strategy on the occurrence of postoperative atrial fibrillation. The association between the occurrence of postoperative atrial fibrillation and preoperative, intraoperative, and postoperative data from the total study population and the amiodarone and placebo subpopulations were explored using multiple logistic regression analysis. Results The following clinical factors were independent predictors of postoperative atrial fibrillation in the total population: age ( p p = 0.021), diabetes mellitus ( p = 0.008), and high-dose postoperative nonsteroidal antiinflammatory drug use ( p = 0.038). Age ( p = 0.016), history of mitral regurgitation ( p = 0.029), heart failure ( p = 0.010), and postoperative nonsteroidal antiinflammatory drug use ( p = 0.038) were independent predictors when amiodarone was used, and age was the only predictor of postoperative atrial fibrillation ( p = 0.024) among patients treated with placebo. Conclusions This subanalysis demonstrates some novel predictors of postoperative atrial fibrillation, including diabetes mellitus and postoperative nonsteroidal antiinflammatory drug use. We have also demonstrated that predictors of atrial fibrillation differ when prophylactic amiodarone is used.
Evaluating informatics applications : some alternative approaches : theory, social interactionism, and call for methodological pluralism

A review of evaluation literature concerning CDSSs indicates that randomized controlled clinical trials (RCTs) are the 'gold standard' for evaluation. While this approach is excellent for studying system or clinical performance, it is not well suited to answering questions concerning whether systems will be used or how they will be used. Because lack of use of CDSS has been of concern for some years, other evaluation research designs are needed to address those issues. This paper critiques RCT and experimental evaluation approaches and presents alternative approaches to evaluation that address questions outside the scope of the usual RCT and experimental designs. A wide range of literature is summarized to illustrate the value of evaluations that take into account social, organizational, professional, and other contextual considerations. Many of these studies go beyond the usual measures of systems performance or physicians' behavior by focusing on 'fit' of the system with other aspects of professional and organizational life. Because there is little explicit theory that informs many evaluations, the paper then reviews CDSS evaluations informed by social science theories. Lastly, it proposes a theoretical social science base of social interactionism. An example of such an approach is given. It involves a CDSS in psychiatry and is based on Kaplan's 4Cs, which focus on communication, control, care, and context. Although the example is a CDSS, the evaluation approach also is useful for clinical guideline implementation and other medical informatics applications. Similarly, although the discussion is about social interactionism, the more important point is the need to broaden evaluation through a variety of methods and approaches that investigate social, cultural, organizational, cognitive, and other contextual concerns. Methodological pluralism and a variety of research questions can increase understanding of many influences concerning informatics applications development and deployment.
Electrical conductivity studies on CuBr containing Al2O3 particles

The conductivity of CuBr was studied and the role of a second phase, Al2O3, dispersed in CuBr was tested. CuBr melts at 493 C and exhibits three phases in the solid state. CuBr is a good ionic conductor with a transport number for copper ions of virtually unity with weighed proportions of the appropriate chemicals used. The CuBr materials were heated above melting point of CuBr, and the samples were sandwiched between copper electrodes. The ac conductivity, was determined at 1 kHz between 25 and 440 C depending on the sample. It was shown that at low temperatures, the conductivity for CuBr (Al2O3) increased by as much as 100, whereas in the beta phase the conductivity of CuBr containing Al2O3 decreased. The electrical conductivity studies are in agreement with earlier data.
Ovarian Control of Prolactin Secretion During Late Pregnancy in the Rat

The involvement of the ovaries during late pregnancy in the rat upon serum prolactin was investigated. Ovariectomy on day 17 or day 21 of pregnancy prevented the dramatic rise of prolactin found in sham-ovariectomized animals between days 21 and 23 of pregnancy. While animals ovariectomized on day 17 of pregnancy failed to carry viable fetuses beyond day 19 of pregnancy, rats ovariectomized on day 21 of pregnancy had viable pups in utero on day 23 of pregnancy. These data suggest that the rise in serum prolactin during late pregnancy is stimulated by ovarian factors.
Does an increase in the ratio of cytoplasmic NADPH to NADP+ accompanied by a decrease in the ratio of cytoplasmic NADH to NAD+ mediate the actions of insulin?

Abstract This paper proposes that both a decrease in the cytoplasmic ratio of NADH NAD + and an increase in the ratio of NADPH NADP + may account for many biological actions of insulin. Evidence in support of this hypothesis is discussed.
Collective versus unilateral responses to terrorism

Global terrorism presents collective action issues for targeted nations. Proactive measures (e.g., preemptive strikes) against terrorists create external benefits for all at-risk nations. In contrast, defensive actions deflect attacks to softer targets, thereby giving rise to external benefits to protected foreign residents and external costs to venues abroad. Coordinated antiterrorism measures are particularly difficult to achieve when many nations must participate and nonparticipants can undo the efforts of others. Thus, freezing terrorists’ assets or abiding by a no-negotiation pledge pose difficult collective action problems. These same concerns do not plague decisive action against domestic terrorism.
Microgravity Two-Phase Flow Transition

Two-phase flows under microgravity condition find a large number of important applications in fluid handling and storage, and spacecraft thermal management. Specifically, under microgravity condition heat transfer between heat exchanger surfaces and fluids depend critically on the distribution and interaction between different fluid phases which are often qualitatively different from the gravity-based systems. Heat transfer and flow analysis in two-phase flows under these conditions require a clear understanding of the flow pattern transition and development of appropriate dimensionless scales for its modeling and prediction. The physics of this flow is however very complex and remains poorly understood. This has led to various inadequacies in flow and heat transfer modeling and has made prediction of flow transition difficult in engineering design of efficient thermal and flow systems. In the present study the available published data for flow transition under microgravity condition are considered for mapping. The transition from slug to annular flow and from bubbly to slug flow are mapped using dimensionless variable combination developed in a previous study by the authors. The result indicate that the new maps describe the flow transitions reasonably well over the range of the data available. The transition maps are examined and the results are discussed in relation to the presumed balance of forces and flow dynamics. It is suggested that further evaluation of the proposed flow and transition mapping will require a wider range of microgravity data expected to be made available in future studies.
The canonical eIF4E isoform of C. elegans regulates growth, embryogenesis, and germline sex-determination

eIF4E plays a conserved role in initiating protein synthesis, but with multiple eIF4E isoforms present in many organisms, these proteins also adopt specialized functions. Previous RNAi studies showed that ife-3, encoding the sole canonical eIF4E isoform of Caenorhabditis elegans, is essential for viability. Using ife-3 gene mutations, we show here that it is maternal ife-3 function that is essential for embryogenesis, but ife-3 null progeny of heterozygous animals are viable. We find that zygotic ife-3 function promotes body growth and regulates germline development in hermaphrodite worms. Specifically, the normal transition from spermatogenesis to oogenesis in the hermaphrodite germline fails in ife-3 mutants. This failure to switch is reversed by inhibiting expression of the key masculinizing gene, fem-3, suggesting ife-3 resembles a growing number of genes that promote the sperm/oocyte switch by acting genetically as upstream inhibitors of fem-3.
Information Processing and the Slingerland Screening Tests

The application of an information processing model for diagnosing and remediating learning disabled children is the focus of much debate. Although this approach is widely practiced in classrooms, advocated by many leaders in the field, and included in federal definitions, the empirical literature is not supportive, and many researchers are ready to dismiss its validity. One of the problems associated with this approach is the assessment instruments. This article reviews both sides of this controversy and suggests the use of the Slingerland Screening Tests as an alternative diagnostic tool for examining information processing skills. A brief overview of this test is presented as well as a discussion of advantages and purposes relevant to the information processing approach. Implications for subsequent research are suggested.
Measurement of Hemoglobin A1c: A new twist on the path to harmony

Evaluation of glycemia is used for the diagnosis and management of patients with diabetes. Glucose and hemoglobin A1c (HbA1c) provide complementary information and both are used to assess an individual’s glycemic status. The concentration of glucose in the blood indicates the subject’s glycemia at the time of blood sampling. However, blood glucose concentrations are modified by numerous factors, ranging from food ingestion and exercise to stress and medication (1). By contrast, the concentration of HbA1c in the blood reflects the average glucose over the preceding 8–12 weeks. Thus, HbA1c provides an additional criterion for assessing glucose control that is free of the wide diurnal fluctuations that occur with blood glucose. HbA1c has several additional attributes, which render it valuable in the setting of diabetes. These include, but are not limited to, the following: the subject does not need to be fasting, blood can be sampled any time of the day, the sample is stable, and there is very little biological variability (1). These factors, in conjunction with the documentation that HbA1c predicts the development of microvascular (2,3) and macrovascular (4) complications of diabetes, have led to the widespread adoption of HbA1c as integral to the management of patients with diabetes. Guidelines from several prominent clinical organizations recommend that HbA1c be measured at regular intervals in all patients with diabetes (5,6). The quality of analytical methods for HbA1c initially lagged considerably behind the evidence of its clinical value. Early assays lacked standardization, substantially limiting the use of HbA1c in patient care. Considerable effort was invested to effect standardization, with schemes developed in the 1990s in Japan (7), Sweden (8), and the U.S. (9). All HbA1c results were reported as a percentage of hemoglobin. The subsequent …
Differences in Substrate Specificities of Five Bacterial Wax Ester Synthases

Wax esters are produced in certain bacteria as a potential carbon and energy storage compound. The final enzyme in the biosynthetic pathway responsible for wax ester production is the bifunctional wax ester synthase/acyl-coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS/DGAT), which utilizes a range of fatty alcohols and fatty acyl-CoAs to synthesize the corresponding wax ester. We report here the isolation and substrate range characterization for five WS/DGAT enzymes from four different bacteria: Marinobacter aquaeolei VT8, Acinetobacter baylyi, Rhodococcus jostii RHA1, and Psychrobacter cryohalolentis K5. The results from kinetic studies of isolated enzymes reveal a differential activity based on the order of substrate addition and reveal subtle differences between the substrate selectivity of the different enzymes. These in vitro results are compared to the wax ester and triacylglyceride product profiles obtained from each organism grown under neutral lipid accumulating conditions, providing potential insights into the role that the WS/DGAT enzyme plays in determining the final wax ester products that are produced under conditions of nutrient stress in each of these bacteria. Further, the analysis revealed that one enzyme in particular from M. aquaeolei VT8 showed the greatest potential for future study based on rapid purification and significantly higher activity than was found for the other isolated WS/DGAT enzymes. The results provide a framework to test prospective differences between these enzymes for potential biotechnological applications such as high-value petrochemicals and biofuel production.
Effect of competitive inhibitors on the inactivation of D-amino acid oxidase and its protein component by oxygen.

Abstract Competitive inhibitors of d -amino acid oxidase decrease inactivation of the oxidase by oxygen, but do not protect the protein component of the oxidase against the inactivation. This implies interaction between the inhibitors and oxidase that does not occur between the inhibitors and catalytic protein. The order of effect of the inhibitors on the inactivation of the oxidase and oxidase activity is the same. The results are compatible with the hypothesis that in the formation of the ternary complex of catalytic protein, flavine nucleotide, and inhibitor, the initial, obligatory step is the formation of the oxidase.
An Unusually High Blood Cocaine Concentration in a Fatal Case

A fatal case resulting in an unusually high blood cocaine concentration is reported. Cocaine was administered intranasally, then orally. Blood concentrations of cocaine and the combination of cocaine and its metabolites were 51.7 and 85.0 mg/L, respectively. Case history, pathological findings, and tissue distribution of cocaine and its metabolites are presented.
On the limits of clustering in high dimensions via cost functions

This paper establishes a negative result for clustering: above a certain ratio of random noise to nonrandom information, it is impossible for a large class of cost functions to distinguish between two partitions of a data set. In particular, it is shown that as the dimension increases, the ability to distinguish an accurate partitioning from an inaccurate one is lost unless the informative components are both sufficiently numerous and sufficiently informative. We examine squared error cost functions in detail. More generally, it is seen that the VC-dimension is an essential hypothesis for the class of cost functions to satisfy for an impossibility proof to be feasible. Separately, we provide bounds on the probabilistic behavior of cost functions that show how rapidly the ability to distinguish two clusterings decays. In two examples, one simulated and one with genomic data, bounds on the ability of squared-error and other cost functions to distinguish between two partitions are computed. Thus, one should not rely on clustering results alone for high dimensional low sample size data and one should do feature selection. Copyright © 2010 Wiley Periodicals, Inc. Statistical Analysis and Data Mining 4: 30–53 2011 (H. Koepke was partially supported by the NSERC operating grant held by the second author.)
Similarity and Priority of the Submarine Officer of the Deck: Assessing Knowledge Structures

It is increasingly being recognized that understanding expert knowledge structures associated with critical decision processes may facilitate Naval personnel performance. Toward this end, system developers and training researchers attempt to identify critical components of expert operator assessment and knowledge. Differing domains of practice rely to varying degrees on perceptual and conceptual knowledge. Perceptual knowledge is relied upon for recognizing critical cues in the environment whereas conceptual knowledge is used to interpret the meaning and importance of these cues. We focus on conceptual knowledge given its importance in the submariner environment. Via analyses of submariner knowledge for concepts related to responsibilities for the Officer of the Deck (OOD) watchstander we examined how training may alter knowledge representation and priority of conceptual importance and how overlap in mental models may be due to amount of experience.
Rye grass cross-reacting allergens in leaves from seven different grass species

Abstract Whole grass plants were collected in Rochester, MN during the month of June. Grass leaves, excluding the pollinating parts of the plants, were washed with distilled water, extracted and analyzed for rye grass allergens by RAST inhibition. Rye grass pollen allergens were found in orchard grass, brome, Timothy, June and annual rye leaves. No such allergenic activity was found in blue grass and canary grass leaves. These results are in contrast with pollen extracts. All pollens, including canary and blue grass, did contain rye group allergens. The fact that grass pollen allergen is present in the leaves of lawn grasses is consistent with the hypothesis that allergen aerosolized from the leaves during mowing contribute to the allergic symptoms of grass allergic individuals.
Preferential Oxidation of CO in H2 on Pure Co3O4−x and Pt/Co3O4−x

Driven by the development of a catalyst made of earth-abundant elements for on-board purification of H2 of this energy conversion technology, preferential oxidation (PROX) on pure Co3O4 nanorods and Co3O4 nanorods with supported Pt nanoparticles was explored with the aid of in situ studies. This catalyst remains its 100 % conversion of CO in H2 at a gas hourly space velocity of 42 857 mL h−1 g−1 at 120 °C for at least 96 h. In situ studies showed that the active surface phase during PROX is nonstoichiometric Co3O4−x. A correlation between density of surface oxygen vacancies and conversion of CO to CO2 suggest that oxygen vacancy is a necessary component of a catalytic site for PROX on Co3O4−x. Compared to pure Co3O4 nanorods, anchoring Pt nanoparticles on Co3O4 nanorods unfortunately increases selectivity for oxidation of H2 owing to the low dissociation barrier of molecular H2 on Pt. Co3O4−x exhibits much higher selectivity for CO oxidation in PROX than Pt/Co3O4−x at a temperature lower than 140 °C.
Relationships among repair, mutagenesis, and survival: overview.

In genetically damaged cells, the pathways of survival, mutagenesis, and repair are inseparable. An irradiated or chemically treated cell, having sustained potentially lethal damage to its DNA, may or may not survive. Surviving, it may or may not have kept intact its store of genetic information. The fate of such a cell depends in part upon the nature and degree of primary DNA damage, in part upon the DNA repair systems available to the cell which are capable of neutralizing the damage, and to an important extent also upon the internal and external environmental factors which determine how effectively repair mechanisms can operate. A surviving cell may have undergone a mutation either because an unrepaired DNA lesion has generated a replication error or because an error-prone repair system has changed the base sequence in the course of restoring a viable DNA structure (see Witkin, 1969; Bridges, 1969; Kondo, 1973; Doudney, 1974).
A range correction for ICESat and its potential impact on ice-sheet mass balance studies

Abstract. We report on a previously undocumented range error in NASA's Ice, Cloud and land Elevation Satellite (ICESat) that degrades elevation precision and introduces a small but significant elevation trend over the ICESat mission period. This range error (the Gaussian-Centroid or "G-C" offset) varies on a shot-to-shot basis and exhibits increasing scatter when laser transmit energies fall below 20 mJ. Although the G-C offset is uncorrelated over periods ≤ 1 day, it evolves over the life of each of ICESat's three lasers in a series of ramps and jumps that give rise to spurious elevation trends of −0.92 to −1.90 cm yr−1, depending on the time period considered. Using ICESat data over the Ross and Filchner–Ronne ice shelves we show that (1) the G-C offset introduces significant biases in ice-shelf mass balance estimates, and (2) the mass balance bias can vary between regions because of different temporal samplings of ICESat. We can reproduce the effect of the G-C offset over these two ice shelves by fitting trends to sample-weighted mean G-C offsets for each campaign, suggesting that it may not be necessary to fully repeat earlier ICESat studies to determine the impact of the G-C offset on ice-sheet mass balance estimates.
Ebola and Marburg Viruses Replicate in Monocyte-Derived Dendritic Cells without Inducing the Production of Cytokines and Full Maturation

Ebola virus (EBOV) and Marburg virus (MARV) cause rapidly progressive hemorrhagic fever with high mortality and may possess specialized mechanisms to evade immune destruction. We postulated that immune evasion could be due to the ability of EBOV and MARV to interfere with dendritic cells (DCs), which link innate and adaptive immune responses. We demonstrate that EBOV and MARV infected and replicated in primary human DCs without inducing cytokine secretion. Infected DC cultures supported exponential viral growth without releasing interferon (IFN)-alpha and were impaired in IFN-alpha production if treated with double-stranded RNA. Moreover, EBOV and MARV impaired the ability of DCs to support T cell proliferation, and infected, immature DCs underwent an anomalous maturation. These findings may explain the profound virulence of EBOV and MARV--DCs are disabled, and an effective early host response is delayed by the necessary reliance on less-efficient secondary mechanisms.
INTERACTIONS AMONG FIRE, ASPEN, AND ELK AFFECT INSECT DIVERSITY: REVERSAL OF A COMMUNITY RESPONSE

After a large crown fire in Arizona, we examined the direct and indirect effects of fire and herbivory (and their interaction) on the regeneration of aspen (Populus tremuloides) and arthropod species richness and abundance. We used elk exclosures covering 150 ha and other experiments to examine these interactions. Several major patterns emerged. First, in the absence of elk, there is a positive relationship between burn severity and the regeneration of aspens via asexual reproduction. Specifically, aboveground biomass of aspen resprouts was 10 times greater at sites of high burn severity than in sites of intermediate burn severity, and there was virtually no aspen regeneration without fire. Second, elk selectively browsed aspen ramets in high-severity burn sites two times more intensely than aspen ramets in intermediate-severity burn sites, largely negating the enhanced regeneration that would have otherwise occurred, thus resulting in three times greater regeneration in intermediate burn sites than in high burn sites. Third, fire and elk browsing had opposing impacts on an arthropod community composed of 33 taxa from 11 orders and 21 families. Fire severity alone showed no effect on arthropod richness and abundance; however, intermediate-severity fire and moderate levels of elk browsing resulted in 30% greater richness and almost 40% greater abundance. In contrast, high-severity fire and high levels of elk browsing resulted in 69% lower arthropod richness and 72% lower abundance. Fourth, the interaction of fire intensity and selective elk browsing resulted in four arthropod community types where the overall mosaic produced the greatest diversity. Our study demonstrates that patterns can completely reverse depending on the factors involved. This argues against a reductionist perspective and argues for studies incorporating greater complexity. At the very least, we need to be aware of such biases and consider how they may alter important decisions that affect basic ecological theory and management practices.
A comparison of D-, E-, and F-speed conventional intraoral radiographic films in endodontic measurement

Abstract Objectives. We sought to compare observer measurement error and subjective ratings for International Standards Organization D-, E-, and F-speed direct exposure dental x-ray films used to determine endodontic working lengths. Methods. Radiographs were exposed to achieve a standard background density of approximately 2.0. Three human maxillary posterior teeth for which No. 10 K-files had been placed at various lengths within 4 canals were studied in a cadaver section. A total of 30 radiographs were used (10 from each film type). Five licensed dentists excluding all authors viewed the radiographs independently and in random sequence. Distances from the file tips to the radiographic apices were measured and were compared with known lengths for error determination. The observing dentists also subjectively rated the images as desirable or undesirable. Statistical methods included a 3-factor ANOVA with Tukey honestly significant difference post hoc analysis to compare objective measurements and chi-square with respect to subjective ratings. Results. No significant differences were attributable to film speed grouping or observers (P >.05); however, there was a specimen effect in that a significant difference was found in measurement accuracy among the 4 canals (P .05). Conclusion. All 3 film types were similar in objective and subjective ratings. This being the case, the faster film is preferred to minimize the radiation dose to the patient. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;93:337-40)
Sequence-Specific Recognition of DNA by a Major and Minor Groove Binding Ligand

A combination of the binding models for the simultaneous recognition of both grooves of DNA led to the design of a polyamide–oligonucleotide ligand that binds to a specific DNA sequence with an association constant of K_a > 2 × 10^(10) M^(−1). The oligonucleotide portion forms a triple helix in the major groove of DNA, and the polyamide unit forms a hairpin in the minor groove (see ribbon model below).
Passing the baton: The pediatric surgical perspective on transition.

Abstract Background/Purpose Transition of care from pediatric to adult providers is garnering intense national interest in pediatrics but is largely driven by nonsurgeons. We sought to describe the preferences of pediatric surgeons and their current transition practice patterns for various populations and wondered whether gender, experience, or practice setting affected surgeons' perspectives. Methods All American Pediatric Surgical Association (APSA) members were surveyed electronically. Responses were voluntary and confidential. Results Survey response rate was 22%. Most surgeons (95%) treated patients up to 22years of age, and many cared for older patients (23–26years, 49%; 27–30years, 25%; 31–40years, 18%; >40years, 13%). Developmentally delayed adults comprised a significant portion of this population (54%). Congenital conditions such as Hirschsprung disease (25%), anorectal malformations (22%) and cystic fibrosis (22%) were most commonly reported. About half (52%) of respondents reported institutional limits for age. Lack of qualified adult surgeons was felt to be the greatest barrier to transition ( p Conclusions Pediatric surgeons care for adult patients with a variety of surgical conditions, particularly those with developmental delay and congenital anomalies. The perception of a deficit of qualified adult providers warrants further exploration. Understanding the barriers to surgical transition represents a critical step in improving the quality and appropriateness of care transitions.