cssi/SciSciGPT-SciSciNet huggingface dataset:
Gating-Related Conformational Changes in the Outer Vestibule of KcsA: a Fluorescence and Pulsed-Epr Analysis

In K+ channels, the selectivity filter and surrounding structures play a crucial role in inactivation gating and flicker. KcsA is a pH-gated K+ channel and its gating is modulated by transmembrane voltage. In this work, we monitored the gating-related structural dynamics in the outer vestibule of KcsA using site-directed NBD fluorescence and pulsed-EPR analysis. Fluorescence polarization results show that in KcsA, the dynamics of the outer vestibule is substantially different when comparing inactivating (wild type) and non-inactivating (E71A) forms of the channel. In addition, the rate of solvent relaxation (dynamics of hydration) is found to be faster in non-inactivating form of KcsA upon gating as determined by red edge excitation shift (REES) analysis. This increased rate of solvent relaxation correlates well with the increased rotational mobility of the outer vestibule residues in the open, non-inactivating state (E71A at pH 4). To gain further insight on the dynamic properties of these conformational fluctuations in the outer vestibule of KcsA during gating, four pulse Double-Electron-Electron Resonance (DEER) EPR spectroscopy is being currently used. This approach allows for the determination of inter-subunit distances between 20-60 A, directly informing on the overall distance distribution. We have used tandem dimer constructs of spin-labeled KcsA for the residues corresponding to the outer vestibule of KcsA to determine average distances and distance distributions at low pH, under conditions that stabilize the inactivated (wild-type filter) and the non-inactivating (E71A) states. The results will be discussed in terms of the conformational transitions in the outer vestibule during activation and inactivation gating.
Evaluation of experimental strategies for the development of chiral chromatographic methods based on diastereomer formation

The past two decades has seen explosive growth in the field of chirality as illustrated by the rapid progress in the various facets of this intriguing field. Firstly, it is the basic understanding of the importance of chirality and, secondly, the awareness of the therapeutic pitfalls due to failure to recognize chirality that have paved the way for a rejuvenated interest in the field. Needless to say that the impetus for chiral separation advancement and enhancement has been found to be the highest in the past decade and still continues to be an area of high focus. In this regard, both direct and indirect separation approaches have been instrumental in placing into literature stereoselective pharmacokinetic and pharmacodynamic data of plethora of drug racemates. Also, today, the cloud of uncertainty associated with the development of a chiral molecule is a thing of the past because the field is so evolved and numerous options are available for stereoselective analysis. However, the decision to advance either a single enantiomer or a racemate for development has to be made by a rational approach with adequate justification. Although indirect method of chiral separation has been well established with numerous examples of well-documented cases of stereoselective pharmacokinetic data, there is a growing need for a review that provides a strategic overview of considerations and key issues for developing chromatographic methods based on diastereomer formation. This review provides a general framework for the exploratory planning and a definitive game plan for the establishment of chiral methods based on diastereomer formation. Also, it provides an exhaustive list of applications of numerous chiral derivatization reagents that have been used in the generation of stereoselective pharmacokinetic data.
Is it what we know or who we know? Choice of organism and robustness of inference in ecology and evolutionary biology: (American Society of Naturalists Presidential Address).

Ecology and evolutionary biology are amazing enterprises. Thousands of practitioners in hundreds of institutions around the world make idiosyncratic decisions about which questions to study, which organisms to use, and for how long, guided by a combination of individual predilection, inspiration from journals and books, and exchanges of progress reports and discussion at professional meetings. No synod of presbyters sets priorities, and no court of sagacious elders adjudicates disputes over which theory is the better explanation for a collection of data. From this swirling mix, principles form and a body of knowledge emerges. These are then collected into monographs and textbooks whose consistency might seem little short of miraculous, given the process. As in many academic disciplines, the epistemic basis of ecology and evolutionary biology, the set of principles and facts that we believe to be true, is the cumulative result of a remarkable self-organizing process. Ecology and evolutionary biology are not focused on the uniform behavior of fundamental particles but on fun-
Revealing substituent effects on the electronic structure and planarity of Ni-porphyrins

Abstract Using density functional theory, we have studied the effects on structural and electronic consequences (including HOMO–LUMO energy gaps, vertical ionization potentials (IP v ), and vertical electron affinities (EA v )) of the following two factors: (a) meso - and β-substituents acting as inductive donors (CH 3 ), inductive acceptors that are electron-donating through resonance (Br), inductive electron acceptors (CF 3 ), and resonance enabled acceptors (NO 2 ); and (b) complete replacement of pyrrole nitrogens with P-atoms. The principal results of the study are: (1) For the bare Ni-porphyrin, the solvents were found not to affect the HOMO–LUMO gaps but to change the IP v and EA v noticeably. (2) In the series CH 3 → Br → CF 3 → NO 2 the HOMO–LUMO energy gaps, IP v , and EA v increase for both meso- and β-substituents. The ruffling distortion of the porphyrin core is retained, and becomes stronger for the two acceptor groups. In general, effects of mes o-substituents on the ruffling distortion of the porphyrin core is more pronounced. (3) Most significantly, complete replacement of pyrrole nitrogens in the NiP with phosphorus atoms produces the species, NiP(P) 4 , with the structural and electronic features drastically different from the original NiP. This implies that NiP(P) 4 can possess interesting and unusual novel properties, including aromaticity and reactivity, leading to its various beneficial potential applications. Furthermore, NiP(P) 4 high stability both in the gas phase and different solvents was shown, implying the feasibility of its synthesis.
Destruction and Complexity An Application of Aesthetic Theory

It is hypothesized that the enjoyment derived from destructive acts is due to the same stimulus characteristics that determine the enjoyment obtained from aesthetic experiences-that is, factors such as complexity, unexpectedness, or novelty manifested in the destruction of the object. A film was constructed that showed a series of panes of glass being broken. Five stimuli representing a wide range of subjectively scaled complexity were used in the experiment. Subjects observed all the panes of glass being broken, and rated preference for breaking each one. Subjects believed that they would be allowed to break a pane of glass of the type rated highest. As predicted, results showed a linear relation between commitment to break an object and subjective complexity.
Risk factors for all-cause, overdose and early deaths after release from prison in Washington state

Abstract Background High mortality rates after release from prison have been well-documented, particularly from overdose. However, little is known about the risk factors for death after release from prison. Therefore, the objective of this study was to determine the demographic and incarceration-related risk factors for all-cause, overdose and early mortality after release from prison. Methods We conducted a retrospective cohort study of inmates released from a state prison system from 1999 through 2003. The cohort included 30,237 who had a total of 38,809 releases from prison. Potential risk factors included gender, race/ethnicity, age, length of incarceration, and community supervision. Cox proportional hazards regression was used to determine risk factors for all-cause, overdose and early (within 30 days of release) death after release from prison. Results Age over 50 was associated with an increased risk for all-cause mortality (hazard ratio [HR] 2.67 for each decade increase, 95% confidence interval [CI] 2.23, 3.20) but not for overdose deaths or early deaths. Latinos were at decreased risk of death compared to Whites only for all-cause mortality (HR 0.61, 95% CI 0.42, 0.87). Increasing years of incarceration were associated with a decreased risk of all-cause mortality (HR 0.95, 95% CI 0.91, 0.99) and overdose deaths (HR 0.80, 95% CI 0.68, 0.95), but not early deaths. Gender and type of release were not significantly associated with all-cause, overdose or early deaths. Conclusions Age, ethnicity and length of incarceration were associated with mortality after release from prison. Interventions to reduce mortality among former inmates are needed.
Isotopomer analysis of cellular metabolism in tissue culture: A comparative study between the pathway and network-based methods

Understanding the metabolism of a cell requires knowledge about the intracellular biochemical structure as well as cellular responses to extracellular nutrients. Towards this goal, genomics and proteomics seek a complete description of the cell’s metabolic network, while the field of metabolomics aims to identify new metabolites and profile their distribution in such a network. Here we employed tracer-based metabolomics to characterize HepG2 metabolic responses to the nutritional environments of two DMEM media containing [1,2 13C2] glucose. A computational model describing 254 reactions of the HepG2 metabolic network was developed to systemically analyze the intracellular flux distribution based on tracer data. This is the largest and most comprehensive model used for isotopomer analysis to date. Estimated reaction fluxes from the model were benchmarked with those obtained from the traditional pathway-based method. Results from this study were as follows: (1) HepG2 cells grow equally well in two test media, including one where asparagine is substituted for the commonly used amino acid glutamine; (2) intracellular flux distributions, particularly in the TCA cycle, are markedly different between cells grown in the two cultures; and (3) compared to the pathway-based method, the network-based approach provides a more complete and detailed picture of substrate utilization as well as informs ways to improve the current media. In short, this network-based, systems biology-driven modeling approach to isotopomer analysis has proven to be a valuable tool for metabolic phenotyping and elucidating the nutrient–gene interactions.
Approximate closest-point queries in high dimensions

Abstract Given n points in d dimensions, we show how to construct a data structure of space O( d 2 d n ) that approximately answers closest-point queries in time O( d 2 d log n ). The returned point is at most O (d> 1 2 ) times further from the query point than the true closest point. We also show how to construct a data structure of space O( dn log m ), that—with high probability—can answer a sequence of m closest-point queries in time O( d log n log m ) per query, with approximation ratio O (d 3 2 ) . Our data structures are based on quadtrees.
User-assisted image compositing for photographic lighting

Good lighting is crucial in photography and can make the difference between a great picture and a discarded image. Traditionally, professional photographers work in a studio with many light sources carefully set up, with the goal of getting a near-final image at exposure time, with post-processing mostly focusing on aspects orthogonal to lighting. Recently, a new workflow has emerged for architectural and commercial photography, where photographers capture several photos from a fixed viewpoint with a moving light source. The objective is not to produce the final result immediately, but rather to capture useful data that are later processed, often significantly, in photo editing software to create the final well-lit image.This new workflow is flexible, requires less manual setup, and works well for time-constrained shots. But dealing with several tens of unorganized layers is painstaking, requiring hours to days of manual effort, as well as advanced photo editing skills. Our objective in this paper is to make the compositing step easier. We describe a set of optimizations to assemble the input images to create a few basis lights that correspond to common goals pursued by photographers, e.g., accentuating edges and curved regions. We also introduce modifiers that capture standard photographic tasks, e.g., to alter the lights to soften highlights and shadows, akin to umbrellas and soft boxes. Our experiments with novice and professional users show that our approach allows them to quickly create satisfying results, whereas working with unorganized images requires considerably more time. Casual users particularly benefit from our approach since coping with a large number of layers is daunting for them and requires significant experience.
228 LONGITUDINAL TRENDS IN LEFT VENTRICULAR CARDIAC OUTPUT IN HEALTHY INFANTS OVER THE FIRST YEAR OF LIFE

We studied left ventricular (LV) cardiac output longitudinally in 16 healthy infants from birth through the first year of life using noninvasive pulsed Doppler ultrasound technique. Ascending aorta blood flow velocity (VAo) was measured with a 5 mHz pulsed Doppler velocimeter. Ascending aortic cross sectional area (AAo) was determined using M-mode echography. Ascending aortic blood flow was calculated as QAo = VAo × AAo and was corrected to body weight (BW) in kilograms or body surface area (BSA) in meters squared. Peak systolic aortic flow velocity averaged 53±2 cm/sec (±SD) over the one year time period. Mean ascending aortic flow velocity (VAo) remained relatively constant over the first year, averaging 20.5±.8cm/sec. Changes in AAo over time correlated with changes in BW and BSA (r = .99) Therefore LV output corrected for body weight or BSA remained relatively constant throughout the first year, ranging from 178-227ml/min/kg or 3.1 - 3.7 L/min/m2 and averaging 204±/15ml/min/kg or 3.5±.2 L/min/m2. A similar strong correlation was seen between serial changes in LV stroke volume and changes in BW or BSA (r = .99). Unlike some other animal species, LV output with respect to BW or BSA changes little in humans over the first year of life.
Physical disability and obesity

Nearly 20% of US citizens are disabled. Epidemiologic studies have shown that people with physical disabilities have a 1.2- to 3.9-fold increase in obesity prevalence. Obesity is becoming a serious problem in disabled individuals. The mechanisms by which obesity occurs in people with physical disabilities is not clear, but pathophysiological changes of body composition and energy metabolism, physical inactivity, and muscle atrophy all favor the development of obesity. Health professionals should identify disabled patients at risk and provide early prevention guidance. Research is needed to help generate detailed clinical guidelines to promote weight control among people with physical disabilities.
Visualization and analysis of phased behavior in Java programs

To enable analysis and visualization of phased behavior in Java programs and to facilitate optimization development, we have implemented a freely-available, phase analysis framework within JikesRVM. The framework couples existing techniques into a unifying set of tools for data collection, processing, and analysis of dynamic phased behavior in Java programs. The framework enables program and optimization developers to significantly reduce analysis time and target optimization (by-hand or automatic) to parts of the code that will recur with sufficient regularity. We use the framework to evaluate phased behavior in the SpecJVM benchmark suite.
Long-integration star tracker image processing for combined attitude-attitude rate estimation

A method is proposed for extracting attitude data from streaked star images using traditional image processing methods. The process enables collection of both attitude and angular velocity estimates from streaking star images, where traditional star identification methods would produce poor results. Star streak endpoints are localized as "corner-like" portions of a streak. A vector cross-product based method is developed to produce a proper grouping in time for endpoints. Star identification and single point attitude determination methods can be applied to each set of endpoints, retrieving two sets of data from a single image. Monte Carlo results are presented, and the implications of the results are discussed. Multiple corner detection methods are considered and compared. Future work needed to mature the process is discussed. Results indicate an endpoint detection accuracy of less than a tenth of a pixel for a camera angle to the rotation axis of greater than 20 degrees and streak lengths up to 40% of the field of view.
Catalysis at the Intersection of Biology, Chemistry, and Medicine

Abstract I have been exceptionally fortunate to hold, as my only professional jobs, faculty positions at two outstanding, research-intensive universities, the Massachusetts Institute of Technology and Harvard University, for almost four decades. This has been an opportunity to work with many of the world's best colleagues and predoctoral and postdoctoral students and to get an unparalleled and continuous education in the exciting scientific currents of this period. While at MIT, I had appointments in both the departments of chemistry and biology as my own personal bridging-biochemistry experience. At Harvard Medical School, in the biological chemistry and molecular pharmacology department for 20-plus years, I have stood at a three-way intersection of biology, chemistry and medicine in an institution with great basic medical science and 26 affiliated hospitals for expertise in any clinical medical specialty. I have taught undergraduates at MIT and Harvard in subjects ranging from organic chemistry to biochemistry and at HMS have taught biochemistry, chemical biology, and pharmacology to medical students and graduate students. What a remarkable set of opportunities!
Moving target detection for distributed MIMO radar with imperfect waveform separation

In this paper, we consider the problem of detecting a moving target with a distributed multiple-input multiple-output (MIMO) radar when perfect waveform separations at the local receivers are no longer valid. By formulating a composite hypothesis testing problem with a subspace modeling of the target residual, the generalized likelihood ratio test (GLRT) is developed by deriving the maximum likelihood (ML) estimates of the unknown parameters. Simulation results are provided to compare the proposed GLRT solution with existing MIMO detectors that do not account for target residuals.
Development of Field-responsive Polymeric Magnetic Composite Fibers via Electrospinning

A mathematical model is developed to predict the changing stiffness of magnetic fibers within a uniform external magnetic field. Magnetite nanoparticles 16nm in diameter were synthesized by an organic route. An ultrafine PMMA fiber containing 16nm magnetite nanoparticles was produced by electrospinning. The magnetic properties of the fibers were also characterized.
THREE-DIMENSIONAL EFFECTS ON SOUND PROPAGATION AND MATCHED-FIELD PROCESSOR PERFORMANCE

The most recent 2-D split-step Pade parabolic-equation model was modified to include narrow-angle azimuthal coupling. This model was developed and applied to the Santa Barbara channel to assess the effect of 3-D propagation on the performance of a matched-field processor. These results, plus those from the Shallow Water Acoustic Modeling (SWAM) workshop's 3-D wedge and the Gaussian canyon cases, will demonstrate the importance of azimuthal coupling to sound propagation in littoral regions and its effect on the performance of a matched-field processor. Special emphasis is given to model limitations and suitable selection of model parameters that could be automated to achieve accurate predictions during production runs.
CD59 incorporation protects hepatitis C virus against complement-mediated destruction

Several enveloped viruses including human immunodeficiency virus type 1 (HIV-1), cytomegalovirus (CMV), herpes simplex virus 1 (HSV-1), Ebola virus, vaccinia virus, and influenza virus have been found to incorporate host regulators of complement activation (RCA) into their viral envelopes and, as a result, escape antibody-dependent complement-mediated lysis (ADCML). Hepatitis C virus (HCV) is an enveloped virus of the family Flaviviridae and incorporates more than 10 host lipoproteins. Patients chronically infected with HCV develop high-titer and crossreactive neutralizing antibodies (nAbs), yet fail to clear the virus, raising the possibility that HCV may also use the similar strategy of RCA incorporation to escape ADCML. The current study was therefore undertaken to determine whether HCV virions incorporate biologically functional CD59, a key member of RCA. Our experiments provided several lines of evidence demonstrating that CD59 was associated with the external membrane of HCV particles derived from either Huh7.5.1 cells or plasma samples from HCV-infected patients. First, HCV particles were captured by CD59-specific Abs. Second, CD59 was detected in purified HCV particles by immunoblot analysis and in the cell-free supernatant from HCV-infected Huh7.5.1 cells, but not from uninfected or adenovirus serotype 5 (Ad5) (a nonenveloped cytolytic virus)-infected Huh7.5.1 cells by enzyme-linked immunosorbent assay. Last, abrogation of CD59 function with its blockers increased the sensitivity of HCV virions to ADCML, resulting in a significant reduction of HCV infectivity. Additionally, direct addition of CD59 blockers into plasma samples from HCV-infected patients increased autologous virolysis. Conclusion: Our study, for the first time, demonstrates that CD59 is incorporated into both cell line-derived and plasma primary HCV virions at levels that protect against ADCML. This is also the first report to show that direct addition of RCA blockers into plasma from HCV-infected patients renders endogenous plasma virions sensitive to ADCML. (HEPATOLOGY 2012)
Neuroendocrine influences on visual discrimination and reversal learning in the albino and hooded rat.

Abstract Pigmented and nonpigmented rats were treated with MSH and MRIH-I and tested on a brightness discrimination and reversal task. Pigmented rats acquired the original habit and performed the reversal task significantly faster than albino rats. MSH and MRIH-I administration significantly facilitated reversal learning performance. Simple effects tests indicated that the effects of MSH and MRIH-I were significant only for albino rats on the reversal task. The data were interpreted to suggest that MSH and MRIH-I affects attentional processes more profoundly in visually deficient animals.
Primary and Secondary Dissociation from Allyl Iodide Excited at 193 nm: Centrifugal Effects in the Unimolecular Dissociation of the Allyl Radical †

In the work presented here. we used photofragment translational spectroscopy and H atom Rydberg time-of-flight (HRTOF) spectroscopy to study the primary photofragmentation channels of allyl iodide excited at 193 nm and the ensuing dissociation of the nascent allyl radicals as a function of their internal energy. Two C-I bond fission channels were found to produce the allyl radical, one channel forming I( 2 P 3 / 2 ) and the other forming I( 2 P 1 / 2 ). The nascent allyl radicals are dispersed as a function of the translational energy imparted from the photolysis and therefore by their internal energy. Although all of the I( 2 P 3 / 2 ) and a portion of the I( 2 P 1 / 2 ) channel allyl radical products have enough internal energy to overcome the 60 kcal/mol barrier to from allene + H, the data showed that a substantial fraction of the allyl radicals from the I( 2 P 1 / 2 ) channel that formed with internal energies as high as 15 kcal/mol above the 60 kcal/mol barrier were stable to H atom loss. The stability is due to centrifugal effects caused by significant rotational energy imparted to the allyl radical during photolysis and the small impact parameter and reduced mass characterizing the loss of an H atom from an allyl radical to form allene + H. A photoionization efficiency (PIE) curve identified the major C 3 H 4 secondary dissociation products as allene. Comparison of the mass 40 signal in the TOF spectra at two photoionization energies showed that branching to H + propyne does not occur at near-threshold internal energies, indicating that the experimentally determined allyl → 2-propenyl radical isomerization barrier, which is lower than recent ab initio calculations of the barrier by ∼15 kcal/mol, is far too low.
Accuracy of the thermodilution method in estimating high flow - an in vitro study

SUMMARY The accuracy of thermodilution for measuring flow rates of 10–40 L/min was evaluated using a commercially available thermodilution cardiac output computer in an in vitro model. Water (36.5–37.5°C) was directed through a mixing chamber via a constant flow pump. Thermodilution estimates of flow using four different volumes (10, 20, 30, 40 ml) of iced water injectate were compared to simultaneous measurements of timed samples of effluent from the mixing chamber. Injectate volume had a significant impact on the accuracy of thermodilution estimation (p 25 L/min. The discrepancy between thermodilution flow and measured flow increased as rate of fluid flow increased.
The mathematics of screening mammography

In an unselected population of women in their early fifties, about 7500 mammograms would have to be performed annually at a cost of U.S. $375,000 per survivor in order to find one woman who would: 1) have an incidental cancer in stage I which was not detectable by physical examination; and 2) owe her survival to the early detection of that cancer. Annual screening mammography has a poor cost-benefit ratio.
On singular perturbation in non well posed problems

Let Leu and L0v be the elliptic and “backward” heat operators defined by(1.1) and(1.2), respectively. The following question is considered for a pair of “non-well posed” initial-boundary value problems for Le and L0: if u and v are the respective solutions, under what restrictions on the classes of admissible solutions and in what sense, if any, does u converge to v as ɛ →0?
The treatment of cardiac neurosis using systematic desensitization.

Abstract During the past 2 yr I have utilized desensitization in a private practice setting. Treatment was attempted in eighty patients. The types of cases treated ranged from patients exhibiting circumscribed habit disorders through phobias and anxiety states to schizophrenia. Treatment was most successful in two groups of patients; those presenting with circumscribed disorders (e.g. stuttering or frigidity) and those with phobias or anxiety states. The results and uses of this treatment can be best exemplified in the management of cardiac neuroses, including one patient where the neurosis was superimposed on underlying organic disease.
Crop insurance loss experience, ratings changes, and impacts on participants

Purpose – The purpose of this paper is to provide empirical information about the past loss experience in major US crop insurance programs, and documents the impacts of ratings changes through time on the premiums and exposure to participants. The losses are also examined within the structure of the current SRA to identify impacts on insurance companies and the government by fund designation. Design/methodology/approach - The study uses RMA Summary of Business data and methods consistent with the use of loss-cost ratemaking to analyze loss performance across years with different starting prices and volatilities. Additionally, the RMA premium quoting system was replicated across years with the ability to adjust only one feature at a time to isolate the impacts of changes in individual rating elements from changes in market conditions. Tabulations are provided in map and table form to present the loss ratios through time, in aggregate across time, and within each of the possible funds in which exposures are...
Nanoindentation technique for characterizing cantilever beam style RF microelectromechanical systems (MEMS) switches

A nanoindentation technique was used to mechanically actuate a radio frequency micro-switch along with the measurement of contact resistance to investigate its applicability to characterize deflection and contact resistance behaviors of micro-sized cantilever beam switches. The resulting load?displacement relationship showed a discontinuity in slope when the micro-switch closed. The measured spring constants reasonably agreed with theoretical values obtained from the simple beam models. The change in contact resistance during test clearly indicated micro-switch closure but it did not coincide exactly with the physical contact between two electric contacts due to a resistive contaminated film.
A computationally-efficient, semi-implicit, iterative method for the time-integration of reacting flows with stiff chemistry

A semi-implicit preconditioned iterative method is proposed for the time-integration of the stiff chemistry in simulations of unsteady reacting flows, such as turbulent flames, using detailed chemical kinetic mechanisms. Emphasis is placed on the simultaneous treatment of convection, diffusion, and chemistry, without using operator splitting techniques. The preconditioner corresponds to an approximation of the diagonal of the chemical Jacobian. Upon convergence of the sub-iterations, the fully-implicit, second-order time-accurate, Crank-Nicolson formulation is recovered. Performance of the proposed method is tested theoretically and numerically on one-dimensional laminar and three-dimensional high Karlovitz turbulent premixed n-heptane/air flames. The species lifetimes contained in the diagonal preconditioner are found to capture all critical small chemical timescales, such that the largest stable time step size for the simulation of the turbulent flame with the proposed method is limited by the convective CFL, rather than chemistry. The theoretical and numerical stability limits are in good agreement and are independent of the number of sub-iterations. The results indicate that the overall procedure is second-order accurate in time, free of lagging errors, and the cost per iteration is similar to that of an explicit time integration. The theoretical analysis is extended to a wide range of flames (premixed and non-premixed), unburnt conditions, fuels, and chemical mechanisms. In all cases, the proposed method is found (theoretically) to be stable and to provide good convergence rate for the sub-iterations up to a time step size larger than 1 µs. This makes the proposed method ideal for the simulation of turbulent flames.
HYPOTHYROIDISM IN CHILDHOOD. IV. THE CREATINE AND CHOLESTEROL RESPONSE TO THYROTROPIC HORMONE1

IN STUDYING cases of hypothyroidism and of dwarfism, information concerning the ability of the thyroid to respond to the stimulation of the thyrotropic hormone of the pituitary should be of importance. A number of workers have tested the effect of the injection of thyrotropic hormone in adult patients by measuring the basal metabolic rate. In a few cases the effect of thyrotropic hormone upon the creatine excretion has been studied also. Schittenhelm and Eisler (1) reported in 1932 that injection of pituitary thyrotropic hormone brought about a 20% increase in the B.M.R. of a healthy young woman, whereas it had no effect on the B.M.R. in a case of post operative myxedema. Eitel and Loeser (2) found a rise of B.M.R. from 15 to 42% in seven days after injecting 600 u of thyrotropic hormone daily in 10 normal adults. Feuling (3) reported an increase of the B.M.R. of 15 to 19% in 57 patients in whom thyrotropic hormone was injected for 4 days. Wachstein (4) found that a patient with myxedema having a B.M.R. o...
Sodium dinonyl naphthalene sulphonate as liquid ion-exchanger☆

Abstract Solutions of sodium dinonyl naphthalene sulphonate and sodium hydrogen dinonyl naphthalene sulphonate in nonpolar organic liquids are shown to serve as analogues of cross-linked resinous cation-exchangers. For cobalt (II)-glycolate and cobalt (II)-citrate systems, the formation constants of the 1:1 complexes agree well with the values obtained by resinous cation-exchange method. Moreover, the liquid exchanger enables the formation constant of the 1:2 complex to be obtained whereas the resinous cation-exchange method fails. Nuclear magnetic resonance studies of the organic phase for cobalt-imidazole and indium-acetate systems demonstrate that CoIm2+ and InAc2+ complexes, with charge of 2+, are extracted into the organic phase. The 1:1 zinc-acetate complex, with a charge of 1+ only, is not extracted. A postulated equation for the extraction of divalent metal ion by sodium dinonyl naphthalene sulphonate, which is polymeric and is designated (NaD)χ is: M 2+ A + (NaD) χo = M(Na χ−2 D χ ) o + 2Na + A where the subscripts A and O denote the aqueuos and organic phases, respectively.
Hypersea and the land ecosystem

Abstract The land ecosystem, in spite of its relative youth, outstrips the marine ecosystem in terms of greater primary productivity and species diversity per unit area. This occurs because land eukaryotes actively direct the flow of nutrient-rich fluids. The body fluids of land eukaryotes have had a significant evolutionary and geochemical impact, and we here refer to these fluids, and the organisms through which they flow, as ‘Hypersea’. Hypersea is a previously unrecognized biogeophysical entity formed by eukaryotic life and its symbionts, parasites and hyperparasites on land. The oldest convincing evidence for Hypersea consists of fossil tracheophytes, mycorrhizal fungi, and protoctists displaying intimate ecological interactions in the Lower Devonian Rhynie Chert (approx. 400 million years old), just older than the first major coal deposits. We use the concept of hypermarine upwelling to help explain both (a) the genesis of coal and (b) why the average species diversity per unit area and biomass production of the land biota has exceeded that of the marine biota for hundreds of millions of years.
Problems interpreting the significance of multiple form patterns of rat liver tyrosine aminotransferase.

Summary Cortisol induced tyrosine aminotransferase (L-tyrosine: 2-oxoglutarate aminotransferase, EC 2.6.1.5) of rat liver cytosol can be resolved into several peaks of activity by CM-Sephadex chromatography. These separable activities have been considered distinct molecular species and are referred to as multiple forms of this enzyme. The present study demonstrates that a number of in vitro manipulations considerably alter the pattern of multiple forms of tyrosine aminotransferase. These include homogenization of the liver in buffers of varying ionic strength and pH, freezing and thawing, and sonication. Based on these findings we conclude that one must proceed cautiously when attempting to relate multiple form patterns observed in vitro to the form(s) of the enzyme in vivo .
The catalysis of the oxidation of some dihydroxybenzene derivatives by various metallic ions

Mn++, Co++, Cu++ and to a certain extent Fe++ catalyzed the oxidation of epinine, 3-hydroxytyramine, N-methyl DOPA, DOPA and catechol, in approximately decreasing order of activity. Tyrosine was not oxidized. In general, Mn++ was the most effective catalyst. During the oxidation of each substrate, CO2 was evolved and hydrogen peroxide was formed. The metallic ion-catalyzed reaction differs from the the tyrosinase-catalyzed oxidation of these compounds in many ways, chief of which are the optimum pH, the rate of oxidation, the specificity toward substrates, the amount of oxygen absorbed per molecule of substrate oxidized and the formation of hydrogen peroxide.
A comparison of postoperative outcomes utilizing a continuous preperitoneal infusion versus epidural for midline laparotomy

Abstract Background Postoperative pain management with a continuous preperitoneal infusion (CPI) for locoregional anesthesia has been shown to have improved postoperative outcomes. This is the first direct comparison of CPI versus epidural infusion (EPI), both in conjunction with systemic analgesia. Methods A retrospective review was performed of midline laparotomy cases, comparing the use of CPI with systemic patient-controlled analgesia to EPI with systemic patient-controlled analgesia for postoperative outcomes. Results A total of 240 cases from 2007 to 2009 were reviewed. There were 41.3% using CPI and 58.7% with EPI. There were no differences with respect to age, body mass index, or American Society of Anesthesiologists score between CPI and EPI cases. In a multivariate model, total hospital stay was 2 days shorter for the CPI group ( P P Conclusions The use of CPI results in decreased length of hospital stay, decreased number of days with a Foley catheter, and lower hospital costs, compared with EPI use. These findings show that the routine use of CPI for pain management after laparotomy is a safe alternative to EPI.
Seasonal Variance in the Diet of Ache Hunter-Gatherers in Eastern Paraguay

Seasonal variance in the diet of Ache hunter-gatherers is examined. Fluctuation in the number of calories of honey consumed daily contributed most to the differences in total calories consumed daily during different seasons of the year. Meat, the most important resource in the diet, provided the greatest number of calories daily, and varied little across seasons. The vegetable component of the diet is characterized by low variance in absolute numbers of calories, but high variance in species composition. The mean number of calories consumed daily per capita is high (3827 calories) compared to that reported for other hunter-gathers. Differences in energy expenditure and consumption among modern hunter-gatherers is discussed.
α5β1 Integrin Ligand PHSRN Induces Invasion and α5 mRNA in Endothelial Cells to Stimulate Angiogenesis

Angiogenesis requires endothelial cell invasion and is crucial for wound healing and for tumor growth and metastasis. Invasion of native collagen is mediated by the α5β1 integrin fibronectin receptor. Thus, α5β1 up-regulation on the surfaces of endothelial cells may induce endothelial cell invasion to stimulate angiogenesis. We report that the interaction of α5β1 with its PHSRN peptide ligand induces human microvascular endothelial cell invasion and that PHSRN-induced endothelial cell invasion is regulated by α4β1 integrin and requires matrix metalloproteinase 1 (MMP-1). Moreover, our results show that exposure to PHSRN causes rapid, specific up-regulation of surface levels of α5β1 integrin and significantly increases α5 integrin mRNA in microvascular endothelial cells. Consistent with these results, α5 small interfering RNA abrogates PHSRN-induced surface α5 and MMP-1 up-regulation, as well as blocking invasion induction. We also observed dose-dependent, PHSRN-induced α5β1 integrin up-regulation on endothelial cells in vivo in Matrigel plugs. We further report that the PHSCN peptide, an α5β1-targeted invasion inhibitor, blocks PHSRN-induced invasion, α5β1 up-regulation, α5 mRNA induction, and MMP-1 secretion in microvascular endothelial cells and that systemic PHSCN administration prevents PHSRN-induced α5β1 up-regulation and angiogenesis in Matrigel plugs. These results demonstrate a critical role for α5β1 integrin and MMP-1 in mediating the endothelial cell invasion and angiogenesis and suggest that PHSRN-induced α5 transcription and α5β1 up-regulation may form an important feed-forward mechanism for stimulating angiogenesis.
Stability of passive time-variable circuits

Lyapunov's second method is used to show that circuits composed of a finite connection of linear, passive, time-variable elements are necessarily stable. Such connections may involve transformers and gyrators as circuit elements, as well as the conventional resistors, inductors and capacitors. An equivalent structure is determined, using only time-variable gyrators to interconnect constant elements consisting of unit capacitors and unit resistors. Using this model, asymptotic stability and uniform asymptotic stability of the original circuit may be investigated. Examples are given to illustrate the methods and concepts.
Contrast sensitivity and acuity of the goldfish

Abstract Photopic contrast thresholds to sinusoidal gratings were measured in five goldfish by conditioning respiration in a Pavlovian paradigm. Vertical gratings were generated on an oscilloscope at a space-averaged luminance of 5 and 23 cd/m2. The CSF (contrast sensitivity as a function of grating spatial frequence) peaked at about 0.3 c/deg, falling off at lower and higher spatial frequencies. CSF's were fitted by double exponential functions that were used to calculate acuity and point-spread functions. Acuity, defined as the half-period of a just resolvable unity contrast grating, ranged in different fish from 13′ to 22′, the smaller value agreeing with the acuity predicted from the intercone separation. The central region of the derived point-spread function subtended about 1.6°, which is smaller than both the smallest ganglion cell receptive field centers, and the limit of full summation previously found for the light-adapted goldfish.
Modeling of electron transport in biomolecules: Application to DNA

We review our work aimed at understanding electron transport in DNA molecules and present new results on specific strands. The motivation for our work stems from both: (i) DNA offering a unique framework for nanoscale electronic devices and (ii) recent work to detect diseases by measuring electrical current in DNA. Designer sequences of DNA show the theoretical possibility to behave as superlattices.
Solution of two-dimensional water-wave propagation problems by Chebyshev collocation

A two-dimensional, elliptic, reduced wave equation was proposed in the mid-seventies to investigate water-wave propagation for coastal engineering applications. However, it is extremely difficult to solve that inseparable, complex equation except for very small sea areas. For larger regions, approximate equation methods such as the ''parabolic equation method'' are used. These methods are inappropriate if wave backscattering or reflections (by bathymetry or structures) are significant. To avoid computational difficulties typical of the elliptic wave equation, the solution of the associated hyperbolic Euler equations has been proposed by several authors who used finite-differences. The finite-difference scheme requires a large number of grid points (in excess of 20 points/wavelength in some cases) to yield satisfactory results. An alternative solution using Chebyshev collocation is considered here. The Chebyshev spectral collocation method yields greater accuracy than finite-differences with far fewer grid points. The feasibility of the method is examined by applying it to problems with wave diffraction and reflection (in the vicinity of breakwaters) and wave refraction-diffraction (by bathymetry). Comparisons of model results with hydraulic model data indicate that the Chebyshev method is an effective tool for simulating two-dimensional wave propagation. Unlike the approximate equation methods, it is not limited to situations of negligible backscattering or paraxiality. Also, it requires comparatively little computer storage, thus enabling its application to larger sea areas.
Predicting antibody hypervariable loop conformation. I. Ensembles of random conformations for ringlike structures.

One approach to finding the conformation of minimum energy for a complicated molecule is to perform energy minimization, perhaps coupled to more exhaustive search procedures such as dynamics or Monte Carlo sampling, from many starting conformation. Where there are geometric constraints on the conformations, as in a ring molecule, or a variable loop starting and ending in known constant regions of one of a series of homologous proteins, rapidly generating many such starting conformations, all satisfying the constraints, has been a problem in the past. We have devised an algorithm, which we call random tweak, which performs this task in the context of a torsional description of a molecule, and have used it to model the backbones of the six CDRs (complementarity determining regions) of the immunoglobulin MCPC603. These range in size from 5 to 19 residues, and have from 8 to 36 variable dihedral angles. Ensembles of 100 properly closed backbone structures for each CDR were generated under several conditions of van der Waals screening internally and against the rest of the molecule, and ensembles of 1000 were generated for selected CDRs. These structure “libraries” reveal how the geometry at the base of a CDR and the topography of the surrounding protein surface restrict the region of space that a given CDR can occupy. In accord with simple notions of chain molecule statistics, the more highly extended a CDR at its base, the more similar the possible structures and the fewer that are necessary to span the conformational space. Energy minimization and molecular dynamics studies (reported elsewhere) using these libraries to furnish starting conformations show that, as the number of residues in a CDR goes from five to nine, the number of randomly generated structures necessary to ensure that low-lying energetic minima, such as the native conformation, will be found several times goes from a few tens to a few hundred. Some of the spatial features of an ensemble of random conformations are implicit in the histogram of the rms atomic displacements calculated for all the pairs in the ensemble. The random tweak method is carried out by setting each dihederal angle on the main chain of the variable fragment to a random value, then using an iterated linearized Lagrange multiplier technique to enforce the geometric constraints with the minimal conformational perturbation. The time required for the algorithm is linear in fragment length, and the resulting ability of the method to handle large loops makes it especially applicable to the modeling of homologous proteins. In most cases, hundreds of acceptable structures could be generated in a few hours on a VAX 11/780. Where van der Waals screening against fixed atoms need not be performed, as for isolated ring molecules, generation times go down by an order of magnitude or more.
Embryos, clones, and stem cells: a scientific primer.

This article is intended to give the nonspecialist an insight into the nuances of “clones”, cloning, and stem cells. It distinguishes embryonic and adult stem cells, their normal function in the organism, their origin, and how they are recovered to produce stem cell lines in culture. As background, the fundamental processes of embryo development are reviewed and defined, since the manipulation of stem cell lines into desired specialized cells employs many of the same events. Stem cells are defined and characterized and shown how they function in the intact organism during early development and later during cell regeneration in the adult. The complexity of stem cell recovery and their manipulation into specific cells and tissue is illustrated by reviewing current experimentation on both embryonic and adult stem cells in animals and limited research on human stem cell lines. The current and projected use of stem cells for human diseases and repair, along with the expanding methodology for the recovery of human embryonic stem cells, is described. An assessment on the use of human embryonic stem cells is considered from ethical, legal, religious, and political viewpoints.