cssi/SciSciGPT-SciSciNet huggingface dataset:
Preparing Synthetic Aβ in Different Aggregation States

This chapter outlines protocols that produce homogenous preparations of oligomeric and fibrillar amyloid -β peptide (Aβ). While there are several isoforms of this peptide, the 42 amino acid form is the focus because of its genetic and pathological link to Alzheimer’s disease (AD). Past decades of AD research highlight the dependence of Aβ42 function on its structural assembly state. Biochemical, cellular and in vivo studies of Aβ42 usually begin with purified peptide obtained by chemical synthesis or recombinant expression. The initial steps to solubilize and prepare these purified dry peptide stocks are critical to controlling the structural assembly of Aβ. To develop homogenous Aβ42 assemblies, we initially monomerize the peptide, erasing any “structural history” that could seed aggregation, by using a strong solvent. It is this starting material that has allowed us to define and optimize conditions that consistently produce homogenous solutions of soluble oligomeric and fibrillar Aβ42 assemblies. These preparations have been developed and characterized by using atomic force microscopy (AFM) to identify the structurally discrete species formed by Aβ42 under specific solution conditions. These preparations have been used extensively to demonstrate a variety of functional differences between oligomeric and fibrillar Aβ42. We also present a protocol for fluorescently labeling oligomeric Aβ42 that does not affect structure, as measured by AFM, or function, as measured by a cellular uptake assay. These reagents are critical experimental tools that allow for defining specific structure/function connections.
Diverse effects of calcium channel blockers on skeletal muscle glucose transport

Verapamil, a calcium channel blocker, inhibited the insulin-stimulated glucose transport rate in isolated rat epitrochlearis muscle in a dose-dependent manner (1-200 microM) without affecting basal glucose transport rate. Verapamil's inhibition was rapid in onset and disappearance; changes in glucose transport rate were detectable when verapamil was added to or removed from the incubation medium 15 min prior to measurement of glucose transport. Verapamil also inhibited the stimulation of muscle glucose transport caused by hypoxia, indicating that the effect was not limited to insulin action. Although the optical isomers of verapamil vary considerably in their potency as Ca2+ channel blockers, they were equally effective inhibitors of insulin-stimulated glucose transport rate. Nifedipine (10-200 microM), a more potent blocker of skeletal muscle Ca2+ channels than verapamil, was less effective as an inhibitor of insulin-stimulated glucose transport. Furthermore, nifedipine (10 microM) did not inhibit hypoxia-stimulated glucose transport. Diltiazem (200 microM), another Ca2+ channel blocker, did not reduce insulin-stimulated glucose transport.
Relative sensitivity of the endogenous hprt gene and lacI transgene in ENU-treated Big Blue B6C3F1 mice.

Three-week-old Big Blue (BB) B6C3F1 mice were given a single i.p. injection of ENU. Three weeks later, splenic T cells were isolated from each animal by ficoll gradient centrifugation and divided into two samples. One sample was cultured to measure hprt- mutation and the other was used to extract DNA for lacI- analysis. T cells from BB mice exposed to 0, 4.5, 13.5, and 40 mg ENU/kg (9 or 10 animals per group) displayed dose-related increases in the frequency of both hprt- and lacI- mutations. Within each treatment group, the ENU-induced mutation frequency (average observed mutation frequency minus average control frequency) was remarkably similar at the two loci. This suggests that treatments that increase mutation frequency at the endogenous hprt gene also produce similar incremental increases at the BB lacI transgene. However, because of the ten-fold higher spontaneous mutation rate at lacI, the fold-increase over background produced by ENU at this locus was significantly less than the fold-increase produced at hprt. For example, the 4.5 mg ENU/kg treatment produced a 5.2-fold increase above background at hprt (P = 0.001), whereas only a 1.5-fold increase was produced at lacI (P = 0.140). Consequently, mutagenic insults that produce up to a fivefold increase in mutation frequency at an endogenous locus may be difficult to detect at the lacI transgene. Finally, the ENU-induced response at hprt in BB mice was identical to that in generic B6C3F1 mice, suggesting that there are no inherent differences between transgenic and normal mice in their response to this mutagenic agent.
A rapid mixing-photocrosslinking technique to study the dynamics of nucleic acid-protein interactions

Abstract A rapid mixing-photocrosslinking technique has been developed to investigate the kinetics of protein-nucleic acid interactions. With this technique, binding of nucleic acid to protein is first synchronized by rapid mixing in a stopped-flow apparatus. The intermediates formed at different stages of the binding process are then “frozen” by photocrosslinking with a 10-μs uv light pulse at various times after mixing. By analyzing structural changes of these intermediates as a function of time, one can obtain the information concerning the dynamic aspects of the interaction. This technique may also be applied to other macromolecular interactions in biological systems.
Chemical weathering in a tropical watershed, Luquillo Mountains, Puerto Rico: I. Long-term versus short-term weathering fluxes

Abstract The pristine Rio Icacos watershed in the Luquillo Mountains in eastern Puerto Rico has the fastest documented weathering rate of silicate rocks on the Earth’s surface. A regolith propagation rate of 58 m Ma−1, calculated from iso-volumetric saprolite formation from quartz diorite, is comparable to the estimated denudation rate (25–50 Ma−1) but is an order of magnitude faster than the global average weathering rate (6 Ma−1). Weathering occurs in two distinct environments; plagioclase and hornblende react at the saprock interface and biotite and quartz weather in the overlying thick saprolitic regolith. These environments produce distinctly different water chemistries, with K, Mg, and Si increasing linearly with depth in saprolite porewaters and with stream waters dominated by Ca, Na, and Si. Such differences are atypical of less intense weathering in temperate watersheds. Porewater chemistry in the shallow regolith is controlled by closed-system recycling of inorganic nutrients such as K. Long-term elemental fluxes through the regolith (e.g., Si = 1.7 × 10−8 moles m−2 s−1) are calculated from mass losses based on changes in porosity and chemistry between the regolith and bedrock and from the age of the regolith surface (200 Ma). Mass losses attributed to solute fluxes are determined using a step-wise infiltration model which calculates mineral inputs to the shallow and deep saprolite porewaters and to stream water. Pressure heads decrease with depth in the shallow regolith (−2.03 m H2O m−1), indicating that both increasing capillary tension and graviometric potential control porewater infiltration. Interpolation of experimental hydraulic conductivities produces an infiltration rate of 1 m yr−1 at average field moisture saturation which is comparable with LiBr tracer tests and with base discharge from the watershed. Short term weathering fluxes calculated from solute chemistries and infiltration rates (e.g., Si = 1.4 × 10−8 moles m−2 s−1) are compared to watershed flux rates (e.g., Si = 2.7 × 10−8 moles m−2 s−1). Consistency between three independently determined sets of weathering fluxes imply that possible changes in precipitation, temperature, and vegetation over the last several hundred thousand years have not significantly impacted weathering rates in the Luquillo Mountains of Puerto Rico. This has important ramifications for tropical environments and global climate change.
Isoproterenol and glucagon effects in perfused hearts from spontaneously hypertensive and normotensive rats.

Abstract The metabolic effects of isoproterenol and glucagon were compared in perfused hearts from spontaneously hypertensive (SH) Wistar rats and normotensive (NT) Wistar controls. Animals were used when either 13–15 weeks of age or when 40–44 weeks of age. Isoproterenol (3 × 10−8 M) or glucagon (10−7 M) was infused over a 3-min period of time. The hearts were subjected to freeze-clamping and emersion in liquid nitrogen and the powdered tissue was assayed for cyclic AMP, phosphorylase activity and glycogen. Glycerol release into the perfusate was also measured. The alterations in these parameters produced by isoproterenol were the same in both the SH and NT hearts. However, the hearts from the SH rats were less responsive to glucagon than those from the NT animals. Infusion of glucagon in isolated hearts of SH rats resulted in increases in cyclic AMP levels and phosphorylase activation which were only 25–50 per cent of those observed with the hearts from the NT rats. Glycerol release from the hearts of the SH rats was delayed after glucagon infusion and reached its maximum response 1 min after the maximum response was achieved in the hearts from the NT rats (45 sec). Infusion of glucagon resulted in a 30 per cent decrease in glycogen content of the hearts from NT rats but produced no significant change in the glycogen content of the hearts from SH rats. Cyclic AMP phosphodiesterase activity was found to be the same in the hearts of the two types of animals. These data demonstrate a diminished response to glucagon in hearts from SH rats possibly due to an alteration in the glucagon receptors.
THE ROLE OF THE HUMORAL IMMUNE SYSTEM IN CHILDHOOD IDIOPATHIC THROMBOCYTOPENIC PURPURA (ITP)

The pathogenesis of childhood ITP is not well understood. To explore the role of the humoral immune system in ITP, bone marrow (BM) and splenic (Sp) lymphocytes from ITP and control children were cultured and in vitro IgG production was measured; in some cases platelet specificity was assessed. Platelet-associated IgG (PAIgG) was also determined as a measure of platelet-bound antibody or complexes. BM and Sp cells were cultured in 20% fetal calf serum, Dulbecco's medium, for 10 days. The Fab-anti-Fab immunoassay was used in all IgG determinations. Platelet specificity was determined using an IgG absorption technique. PAIgG of circulating platelets from control and ITP subjects was assayed directly after washing the platelets by gel filtration. Mean BM synthesis rates (ngIgG/106 lymphocytes/day) of acute and chronic ITP cases were 219±92 and 619±216; both were significantly greater than control values of 98±62 (p<0.01 and 0.001 respectively). SpIgG synthesis rates of chronic cases and controls were 85.9±52 and 22.9±11, respectively, and differed significantly (p< 0.001). Four of 4 splenic samples showed significant binding to target platelets which averaged 1232 ngIgG/109 platelets. Blood PAIgG values (ngIgG/10 platelets) of acute cases (range 5588–56,250) and chronic cases (range 2425–16,800) were greater than control values of 1089±213 (p<0.001) and the two ITP groups appeared to reflect different statistical populations. We conclude these data support immune-mediated platelet destruction in both acute and chronic childhood ITP. Differences in PAIgG values, although preliminary, may be of diagnostic importance and suggest different mechanisms may be involved.
Interventional nutrition for cardiac disease

Animals with cardiac disease can have a variety of nutritional alterations for which interventional nutrition can be beneficial. Deviation from optimal body weight, both obesity and cachexia, is a common problem in cardiac patients and adversely affects the animal. Methods for maintaining optimal weight are important for good quality of life in dogs and cats with cardiac disease. Providing proper diets to prevent excess intake of sodium and chloride also is important, but severe salt restriction may not be necessary until later stages of disease. Certain nutrient deficiencies may play a role in the pathogenesis or complications of cardiac disease, but nutrients also may have effects on cardiac disease which are above and beyond their nutritional effects (nutritional pharmacology). Supplementation of nutrients such as taurine, carnitine, coenyzme Q10, and omega-3 polyunsaturated fatty acids may have benefits in dogs or cats with cardiac disease through a number of different mechanisms. By addressing each of these areas maintaining optimal weight, avoiding nutritional deficiencies and excesses, and providing the benefits of nutritional pharmacology, optimal patient management can be achieved.
Regulation of cyclin D-dependent kinase 4 (cdk4) by cdk4-activating kinase.

Abstract The accumulation of assembled holoenzymes composed of regulatory D-type cyclins and their catalytic partner, cyclin-dependent kinase 4 (cdk4), is rate limiting for progression through the G1 phase of the cell cycle in mammalian fibroblasts. Both the synthesis and assembly of D-type cyclins and cdk4 depend upon serum stimulation, but even when both subunits are ectopically overproduced, they do not assemble into complexes in serum-deprived cells. When coexpressed from baculoviral vectors in intact Sf9 insect cells, cdk4 assembles with D-type cyclins to form active protein kinases. In contrast, recombinant D-type cyclin and cdk4 subunits produced in insect cells or in bacteria do not assemble as efficiently into functional holoenzymes when combined in vitro but can be activated in the presence of lysates obtained from proliferating mammalian cells. Assembly of cyclin D-cdk4 complexes in coinfected Sf9 cells facilitates phosphorylation of cdk4 on threonine 172 by a cdk-activating kinase (CAK). Assembly can proceed in the absence of this modification, but cdk4 mutants which cannot be phosphorylated by CAK remain catalytically inactive. Therefore, formation of the cyclin D-cdk4 complex and phosphorylation of the bound catalytic subunit are independently regulated, and in addition to the requirement for CAK activity, serum stimulation is required to promote assembly of the complexes in mammalian cells.
MADD OPERATION AWARE REDUNDANCY ELIMINATION

On general purpose computer architectures, the optimization of redundancy elimination almost always improves the cycle count. We argue that a specific consideration should be taken when applying this optimization to embedded architectures that feature multiply-add(MADD) instruction. This paper presents a redundancy elimination algorithm with MADD operation aware consideration. It produces optimized results for both code size and cycle count. The algorithm is integrated into KylinC compiler, a compiler for embedded systems developed at the University of Delaware. Experimental results demonstrate that the cycle counts of the benchmark programs are reduced on average 8% and the code sizes are reduced on average 5.27%.
Image recovery using iterative data refinement with relaxation

Iterative data refinement (IDR) is a general procedure for estimating data that would have been collected by an ideal measuring device from data that were collected by an actual measuring device. We show that IDR is general enough to encompass such well-accepted image recovery methods as the Gerchberg-Saxton algorithm and the error reduction and hybrid input-output methods of Fienup. The generalizations provided by IDR give new insights into the nature of such algorithms and, in particular, allow us to introduce the notion of relaxation into them. Along similar lines, DR provides a common framework within which new algorithms can be developed for improved magnetic resonance imaging (MRI). We apply the approach of IDR to a specific problem in MRI, namely, to the correction of spatially dependent blurs due to transverse relaxation. The algorithm is designed to reconstruct 12-weighted spin density images with improved spatial resolution. The practical computational significance of using the IDR approach is illustrated by the reconstruction of mathematical phantoms. We find that overrelaxation of the algorithm can improve computational speed by up to a factor of five.
The physical significance of modons: Laboratory experiments and general integral constraints

Abstract A barotropic jet emerging from a point source in a rotating fluid is deflected to the right (northern hemisphere) and starts to accumulate in an anticyclonic vortex. This gives rise to a cyclonic neighbor, and the dipole (modon) then propagates away from the source in a circular path. A modification of Batchelor's (1967) solution, which takes into account the different strenghts of the anticyclonic-cyclonic pair, is able to account for the path curvature. The experiment shows that highly organized modons can be realized in the laboratory with rather nondescript forcing. The s-effect (not noticeably present in the experiment) should enhance the realizability of these structures in geophysical flows. Therefore, it is suggested that the modon model captures certain essential features of geophysical eddies. This is based on a derived theorem which shows that any slowly varying (not necessarily uniformly propagating) and isolated disturbance on the beta plane must have zero net relative angular momentum, so that the dipole is the simplest dynamically consistent representation of such a disturbance. Some interesting aspects of two-dimensional turbulence in a rotating fluid are also indicated by the laboratory esperiments and by the general integral theorems presented.
Analysis of channel-geometry effects on separation efficiency in rectangular-capillary electrochromatography columns.

Abstract A three-dimensional random walk model was developed to evaluate the impact of column geometry on separation efficiency in chromatography systems driven by electroosmotic flow. Contributions of injection plug length, cross-sectional area of channels, and aspect ratio of rectangular channels were examined in these simulation studies. Sample plug length had no impact on efficiency until it exceeded roughly 0.4% of the channel length. Plate height increased rapidly with increasing k ′ as expected, almost doubling in going from k ′=0.25 to 0.35. Channel geometry also had a major effect on efficiency. Plate height increased sharply in rectangular channel columns until the channel aspect ratio reached 4–8. But the effect of channel depth was even more dramatic. Minimum plate height ( H min ) was roughly half that of the channel depth in ideal cases. H min in a 10×2 μm channel was at 1.6 mm s −1 . Rectangular channels comparable to those obtained by microfabrication are equivalent to packed column capillary electrochromatography columns in all cases.
HOLOMORPHIC FILLING OF ℝP3

We will demonstrate that up to Stein homotopy there is a unique Stein manifold which has a strictly pseudoconvex boundary diffeomorphic to ℝP3. The manifold is a complexification of S2.
Alternatively spliced isoforms of nerve- and muscle-derived agrin: their roles at the neuromuscular junction.

Abstract Agrin induces synaptic differentiation at the skeletal neuromuscular junction (NMJ); both pre- and postsynaptic differentiation are drastically impaired in its absence. Multiple alternatively spliced forms of agrin that differ in binding characteristics and bioactivity are synthesized by nerve and muscle cells. We used surgical chimeras, isoform-specific mutant mice, and nerve–muscle cocultures to determine the origins and nature of the agrin required for synaptogenesis. We show that agrin containing Z exons (Z + ) is a critical nerve-derived inducer of postsynaptic differentiation, whereas neural isoforms containing a heparin binding site (Y + ) and all muscle-derived isoforms are dispensable for major steps in synaptogenesis. Our results also suggest that the requirement of agrin for presynaptic differentiation is mediated indirectly by its ability to promote postsynaptic production or localization of appropriate retrograde signals.
Residual stress evolution due to cool down in viscoplastic metal matrix composites

Abstract Two issues are considered in the current paper: 1. (1) the effect of cool down from processing temperature on the thermally induced residual stresses in a representative volume element (RVE) of a periodic continuous fiber metal matrix composite monolayer. 2. (2) the initiation of microcracks due to subsequent mechanical loading. A nonlinear incremental finite element program that accounts for thermoviscoplasticity in the matrix is utilized for the micromechanical analysis. The uncoupled heat conduction equation is solved for the spatial temperature distribution in the RVE for given cooling rates. Results indicate that spatial thermal gradients can induce significant stresses at rapid cooling rates. Furthermore, comparisons between thermoelastic and thermoviscoplastic predictions of residual stresses at the interface between the fiber and the matrix demonstrate that incorporating viscoplasticity may be significant in predicting certain damage mechanisms such as interfacial and radial matrix cracking. Finally, average stress-strain curves are obtained for the cases of mechanical loading with or without residual stresses, and predictions are made for the location and time at which interface debonding initiates.
Gas separations in hollow-fiber adsorbers

The adsorption of ethane from helium was measured in beds packed with 2.5 {mu}m zeolite crystals and containing either a single hollow fiber or multiple fibers. The single-fiber experiments indicate that the mass-transfer rate in beds containing zeolite 13X is limited by diffusion across the fiber wall and through macropores. For adsorption in single-fiber beds packed with zeolite 4A, mass transfer is limited by micropore diffusion within the particles. Breakthrough curves from beds containing 13X are adequately described with the linear driving force model, while curves from beds containing 4A are consistent with the Rosen model. Breakthrough curves from beds packed with zeolite 13X and containing multiple fibers can be predicted from the experiments with single-fiber beds when the fibers are evenly spaced. When fibers are unevenly spaced, the breakthrough curves are more disperse. Unevenly spaced fibers are the normal case. Even when fibers are evenly spaced, the productivity of hollow-fiber beds is expected to be no greater than that in conventional beds.
On energy conservation characteristics of autoclaved aerated concrete

Cet article discute nombre d'aspects lies aux caracteristiques de conservation de l'energie du beton cellulaire autoclave (BCA). Nous considerons les aspects suivants: 1. L'effect de la crise de l'energie sur la conception des bâtiments, et l'accent mis de plus en plus sur la conservation de l'energie. 2. Les details sur nombre de proprietes thermiques du BCA. 3. L'importance de l'inertie thermique et du comportement thermique dynamique et les avantages que le BCA a, en comparaison avec l'acier et le beton, en tant que materiau leger pouvant fournir une haute isolation combinee avec une haute inertie thermique. 4. La nouvelle norme californienne sur l'energie avec sa preoccupation pour une utilisation totale de l'energie et la toute nouvelle reconnaissance de l'inertie thermique de la ‘masse legere’. 5. Quelques demonstrations concretes de la consommation d'energie plus faible des bâtiments en BCA en comparaison avec les constructions en bois et en beton arme. 6. Les mesures de l'etancheite a l'air d'un bâtiment en BCA.
Chiral high performance liquid chromotography resolution of ibuprofen esters

Two cellulose-based chiral stationary phases (Chiralcel OD and Chiralcel OJ) were compared on their ability to resolve various aliphatic ibuprofen esters. Chiralcel OJ with hexane as the mobile phase allows for the separation of most of the esters. Observed changes in resolution depending on the solute nature (basicity of the solute, esterified alcohol chain length, presence of a double bond) are discussed. An example of the application of this method for following the kinetic resolution of racemic ibuprofen is presented.
Investigation of nonlinear effects leading to laser-induced damage initiation in KDP and DKDP crystals

Laser-induced damage initiation in KDP and DKDP crystal plates using single and multi-wavelength irradiation as a function of laser parameters is investigated. Pre-exposure of the material increases its damage threshold by two different pathways.
Graphene plasmonics for subwavelength terahertz oscillators

Plasmons in population inverted graphene can experience extremely large gain through the process of stimulated emission at terahertz frequencies. The large gain values and the small plasmon wavelengths can lead to compact terahertz plasmon lasers and amplifiers that are only a few microns in size. We also present optical and terahertz spectroscopy results for carrier relaxation and recombination dynamics and terahertz gain in graphene and discuss designs for terahertz plasmon lasers and practical schemes for achieving population inversion in graphene.
Observed transitions in two-phase stratified gas-liquid flow

Abstract The wave transition processes affecting a particular gas-liquid flow configuration, horizontal stratified flow, are investigated experimentally. The spatial evolution of the interfacial instability is found to be one of the main features, yielding an initial region of linear evolution of two-dimensional periodic waves followed by a region where nonlinear effects cause saturation and secondary instabilities. Different experimental techniques are described for the quantitative characterization of the different resulting surface patterns and of the processes leading to their selection.
Silver oxide assisted synthesis of fluoroalkanes; Measurements with a fluoride electrode and with fluorine-18

Abstract Because of the interest in 18F labeled gaseous fluoroalkanes as physiological tracers, a study of several factors which affect their synthesis was undertaken. Silver oxide increases yields of fluoroalkanes. It may function in part as a dehydrating agent, since in its presence reactions are relatively insensitive to added water. Disappearance of fluoride from reaction mixtures was monitored with a fluoride electrode, as well as by transfer of 18F into the gas phase. More fluoride left the system than could be accounted for in labeled gas. This could be due to formation of involatile fluoro-organic compounds or of water-insoluble inorganic complexes of fluoride. It is probably not due to an initial form of 18F other than fluoride ora compound which rapidly exchanges with fluoride.
Value of NAS Energy Storage Toward Integrating Wind: Results From the Wind to Battery Project

Energy storage is a natural option toward adding the much-needed flexibility for integrating higher amounts of wind generation into the existing power system. This paper presents field results and analyses quantifying the ability and the value of Sodium Sulfur (NAS) battery energy storage toward shifting wind generation from off-peak to on-peak, limiting the ramp rate of wind farm output, and a strategy to integrate the aforementioned goals. The battery can also be considered on a system level independent of wind. It is argued that even in its capacity as a system resource independent of wind, the battery can aid integration of wind generation. Analyses quantifying the value of the battery in the energy and operating reserve markets are presented. Financially optimal locations to site the battery have also been identified. The presented research is a part of the “Wind to Battery” project led by Xcel Energy, a major U.S. utility.
Effect of dietary calcium and phosphorus levels on the utilization of calcium, phosphorus, magnesium, manganese, and selenium by adult males

Abstract The effects of dietary calcium and phosphorus levels on the utilization of phosphorus, calcium, magnesium, manganese, and selenium by nine adult males were examined during a 39-day balance study. The dietary treatments were a moderate calcium-moderate phosphorus diet (MCaMP), a moderate calcium-high phosphorus diet (MCaHP), and a high calcium-high phosphorus diet (HCaHP). The moderate and high levels of phosphorus were 843 and 2443 mg daily, respecitvely; the moderate and high levels of calcium were 780 and 2382 mg daily, respectively. Subjects were unable to maintain positive balance in regard to phosphorus when fed the moderate level of phosphorus (MCaMP) but maintained positive balance in regard to phosphorus when fed the high level of phosphorus (MCaHP, HCaHP). The addition of more calcium to the high phosphorus diets resulted in significantly greater excretion of phosphorus in the feces but significantly less excretion of phosphorus in the urine by subjects. The dietary treatments affected urinary excretion of calcium, magnesium, and selenium significantly, but the effects were small or were compensated for by changes in fecal excretion of the minerals. Thus the dietary treatments had no significant effects on overall retention of calcium, magnesium, manganese, and selenium by these subjects.
Paper chromatographic studies of urinary organic acids.

Abstract 1. A new method based on a liquid ion exchange resin has been devised, providing better results than solid resins for the extraction of urinary acids. 2. A new solvent system was used for urine chromatograms, eliminating completely the streaking in the acidic phase, presenting only a few streaks in the basic phase, and separating oxalic acid from other acids well. 3. The characteristics of many as yet unidentified organic acids likely to be found in urine have been described for our system.
Plasma amino acid concentrations in 36 dogs with histologically confirmed superficial necrolytic dermatitis

Plasma amino acid concentrations were measured in 36 dogs diagnosed with superficial necrolytic dermatitis (SND) via skin biopsy. The median age of the dogs was 10 years, and 27 out of 36 (75%) were male. Twenty-two out of 36 (61%) of the dogs were accounted for by six breeds; West Highland white terriers (six), Shetland sheepdogs (five), cocker spaniels (four), Scottish terriers (three), Lhasa apsos (two) and Border collies (two). The mean concentration (+/- standard deviation) was calculated for each measured plasma amino acid and compared to previously documented concentrations of plasma amino acids measured in dogs with acute and chronic hepatitis. The ratio of branched chain amino acids to aromatic amino acids in the dogs with SND was 2.6, slightly lower than that in normal dogs. The mean plasma amino acid concentrations for dogs with SND were significantly lower than for dogs with acute and chronic hepatitis. A metabolic hepatopathy in which there is increased hepatic catabolism of amino acids is hypothesized to explain the hypoaminoacidaemia seen in SND.
A system for measuring complex dielectric properties of thin films at submillimeter wavelengths using an open hemispherical cavity and a vector network analyzer.

Quasi-optical (QO) methods of dielectric spectroscopy are well established in the millimeter and submillimeter frequency bands. These methods exploit standing wave structure in the sample produced by a transmitted Gaussian beam to achieve accurate, low-noise measurement of the complex permittivity of the sample [e.g., J. A. Scales and M. Batzle, Appl. Phys. Lett. 88, 062906 (2006);10.1063/1.2172403 R. N. Clarke and C. B. Rosenberg, J. Phys. E 15, 9 (1982);10.1088/0022-3735/15/1/002 T. M. Hirovnen, P. Vainikainen, A. Lozowski, and A. V. Raisanen, IEEE Trans. Instrum. Meas. 45, 780 (1996)]10.1109/19.516996. In effect the sample itself becomes a low-Q cavity. On the other hand, for optically thin samples (films of thickness much less than a wavelength) or extremely low loss samples (loss tangents below 10−5) the QO approach tends to break down due to loss of signal. In such a case it is useful to put the sample in a high-Q cavity and measure the perturbation of the cavity modes. Provided that the average mod...
Estimating Coefficients in Linear Models: It Don't Make No Nevermind

It is proved that under very general circumstances coefficients in multiple regression models can be replaced with equal weights with almost no loss in accuracy on the original data sample. It is then shown that these equal weights will have greater robustness than least squares regression coefficients. The implications for problems of prediction are discussed. In the two decades since Meehl's (1954) book on the respective accuracy of clinical versus clerical prediction, little practical consequence has been observed. Diagnoses are still made by clinicians, not by clerks; college admissions are still done by committee, not by computer. This is true despite the considerable strength of Meehl's argument that humans are very poor at combining information optimally and that regression models evidently combine information rather well. These points were underlined in some recent work by Dawes and Corrigan (1974), in which they found again that human predictors do poorly when compared with regression models. Strikingly, they found that for some reason, linear models with random regression weights also do better than do humans. Even more striking, when all regression weights were set equal to one another they found still higher correlation with criterion on a validating sample. The obvious question here is Why? Is it because humans are so terrible at combining information that almost any rule works better, or is it some artifact of linear regression?
Hypothesis: AIDS is an autoimmune disease directed at the immune system and triggered by a lymphotropic retrovirus.

Abstract By attaching to the CD4 (T4) molecule of the helper-inducer lymphocyte, the human immunodeficiency virus (HIV) envelope imitates the normal ligand for this receptor, namely, an invariant component of the class II major histocompatibility antigen (MHC). Depending on the degree of antigen mimicry, the normal immune response to retrovirus envelope would be expected to recognize and cross-react to self-MHC. By disguising as “self” the virus then provokes an autoimmune attack of class-II-bearing cells and an anti-idiotypic response to the CD4 antigen. As a consequence of this immune response to virus infection, communication between CD4 lymphocytes and antigen-processing cells becomes blocked, resulting in progressive disruption of antigen recognition, immunodysregulation, and dysfunctional responses of catastrophic proportion. If this hypothesis gains support, then there are profound implications for prevention and treatment.
Organisation of Xenopus egg cytoplasm: response to simulated microgravity.

The cytoplasm of Xenopus fertilised eggs appears to be organised into three major compartments based primarily on the uneven distribution of yolk platelets. There is a shift of these yolk compartments during the first cell cycle that is thought to be involved in the dorsal/ventral morphogenesis of the embryo. The involvement of gravity in Xenopus cytoplasmic organisation and in compartment shifts was addressed by examining, cytologically, the yolk compartments in embryos that developed under the simulated microgravity conditions of the horizontal clinostat. The cytoplasmic organisation into yolk compartments was found to be maintained, and the asymmetric movements of compartments still occurred in eggs that developed on the clinostat. It is suggested that the organisation of Xenopus egg cytoplasm into discrete compartments relies on forces other than those involving gravity (i.e., not density differences), and that the compartment shifts that take place during the first cell cycle are active movements. The variation in compartment size and composition observed from batch to batch of eggs, and to a lesser extent from egg to egg, during this study was addressed.
AKT1 induces caspase-mediated cleavage of the CDK inhibitor p27Kip1 during cell cycle progression in leukemia cells transformed by FLT3-ITD

p27Kip1 cleavage and caspase-3 regulate cell cycle in human myeloma cells and B cells, however regulation of p27Kip1 cleavage during the cell cycle is not known. In BaF3-FLT3-ITD cells, p27Kip1 undergoes C-terminal cleavage. Inhibition of the PI3K/AKT pathway is associated with decreased cleavage of p27Kip1 and G1 phase arrest. A caspase-3 inhibitor reduces p27Kip1 cleavage and inhibits cell proliferation. Knockdown shRNA against AKT1 reduces cleavage of p27Kip1, inhibits caspase-3 activation, and is associated with a delay in cell cycle progression. Taken together, these findings indicate that AKT1 induces caspase-mediated cleavage of p27Kip1, required for G1-S progression in FLT3-ITD cells.
SU‐C‐BRC‐02: Plan Quality and Delivery Efficiency with Varian TrueBeam FFF Mode at High Dose Rate

Purpose: The maximum dose rate at the regular filter mode of a Varian Linac is 600 MU/min. In comparison, the dose rate for flattering filter free (FFF) mode of Varian TrueBeam linac is up to 1400 MU/min at 6MV. The purpose of this study is to investigate the clinical use of IMRT treatment in FFF mode at high dose rate. Method: Ten prostate patients' plans were generated using regular and FFF mode at 6 MV using Eclipse treatment planning system. PTV varies from 122–233 cc. Four types of plans were generated for each patient: multifield IMRT using regular filter mode, multifield IMRT using FFF mode, RapidArc(RA) using filter mode, RA using FFF mode. To facilitate comparison, same constraint table was used for each patient to optimize the fluence. Continuous high definition MLC sequences were generated at maximum dose rate of each mode. Results: With same optimization parameters, the plan quality is comparable for each plan. The maximum doses to target and organs are slightly higher for FFF mode with the same IMRT technique. Total MU for FFF mode and multifield IMRT technique is much higher than their counterparts. Nonetheless the beam‐on time is substantially lower for FFF mode due to higher dose rate. Conclusion: IMRT plans for the two filter modes are comparable. Although the dose rate for FFF mode is much higher than filter mode, FFF mode requires much more MUs to deliver the same amount of dose. Many MUs are used to move MLC leaves to compensate sloping region of beam profile in FFF mode. This reduces MU efficiency when irradiating large targets with irregular shapes. High dose rate treatment in FFF mode is more efficient to SRS treatment for small target. RapidArc technique may help reduce the delivery time for treatment of large target.
Seasonal Changes in Swimming Rates of Yellow Perch in Lake Mendota as Measured by Sonar

Abstract Sonar equipment was used during 1966 to study the relation between seasonally changing temperatures and swimming speeds of yellow perch, Perca flavescens (Mitchill), in Lake Mendota and the movements of the fish with respect to water currents in the lake. From its lowest point during winter (0–5 C) the rate of movement increased with increasing water temperatures until the maximum rate was reached during mid-summer when water temperatures were 20–25 C. As the lake cooled in autumn, the swimming speeds declined. The range of speeds in the frequency distribution during winter was less than that during summer when the distribution was spread out and encompassed a wide range of speeds. The swimming rate increased linearly with increasing temperature. The swimming speeds of individual perch were commonly only one-half those of schools at a given temperature interval suggesting that a “group effect” was correlated with the behavior of the perch schools. No consistent orientation of fishes to the curren...
Competitive oxidation of 6-hydroxydopamine by oxygen and hydrogen peroxide

Abstract Simultaneous oxygen electrode and conventional polarographic measurements show the net concentration of hydrogen peroxide produced by air oxidation of 6-hydroxydopamine is considerably less than that predicted from the known stoichiometry of the reaction. This is due to competitive oxidation of 6-hydroxydopamine by the generated hydrogen peroxide. The presence of ascorbic acid in this reaction also results in significant decreases of hydrogen peroxide under most conditions. The implications of these results to the molecular mechanisms of 6-hydroxydopamine neurotoxicity are discussed.
Territorial intrusions by pikas (Ochotona princeps) as a function of occupant activity

Abstract Pikas ( Ochotona princeps ) defend individual territories on talus. We tested the short-term stability of pika territories and found that although animals may intrude on the territories of conspecifics at any time, they were much more likely to do so if the occupant was inactive. Pikas usually waited until occupants were unavailable to defend their territory before intruding, apparently to avoid detection and repulsion by the occupant. Intruder avoidance of active occupants was most pronounced among same-sex dyads and non-nearest neighbours. Instances of territory intrusion were most frequent among nearest neighbour heterosexual dyads. Most cases of intrusion appeared to be related to eventual relocation of territories, deterring settlement of unfamiliar conspecifics on nearby vacant territories, and/or increasing familiarity with nearest neighbours of the opposite sex.
Darwin's sexual selection: Understanding his ideas in context

Abstract Darwin's writings need to be seen in their fullness, as opposed to quote-mining individual sentences without the context of his passages. Sometimes Darwin wrote at length, apparently favorably, about ideas that he subsequently undermined, replacing them with a more integrative view that reflected his own broad compass. Darwin understood that nature is not simple, that not all members of a group may have evolved under the same selective regime, and that variation of all kinds is fundamental to selection in its several forms. Sexual selection requires sexual dimorphism; it is not centred on variation within sexes but on selection for the ability to acquire mates. “Mutual sexual selection” was rejected by Darwin for every species except humans. Mating success is not a matter of mere numbers but of the transmission of the most attractive features to the opposite sex. The term “sexual selection” should only be used when one sex uses a feature not present in the other sex to attract mates or repel rivals for mates.
End the Plague on the House of Guidance—Make Counseling Part of the Curriculum

While criticisms of guidance programs and personnel are not unfounded, this writer explains, guidance professionals do have a choice. Standards have been developed and exemplary programs identified, providing models for improvement.
Correlation Effects in Atomic Structure Using the Random-Phase Approximation

Abstract : A procedure for treating correlations in atomic structure is introduced and applied to the calculation of excitation energies, oscillator strengths, and photo-ionization cross sections. The method is the extension of the Hartree-Fock theory known as the random-phase approximation, which has already been applied to a number of other many-body problems. In this application to atomic physics, results are given for the following atoms in column II of the periodic table: beryllium, magnesium, calcium, and strontium. These atoms all have 1 sub S ground states, and only excitations to 1 sub P states are considered. The general conclusion of the study is that the values of the oscillator strengths and photo-ionization cross sections are changed significantly by the correlations, while the changes in the values of the excitation energies are quite small. Wherever comparison with experiment is possible, the inclusion of these correlations improves the agreement between theory and experiment. Their effects are, however, not as marked as in highly degenerate infinite systems or in nuclei. (Author)
Hiker impact on herbaceous vegetation along trails in an evergreen woodland of Central Texas

Abstract Because the number of visitors has greatly increased in Meridian State Recreation Area, Texas, three trails in an evergreen woodland were chosen to study the effects of human trampling on non-woody vegetation, leaf litter, trail width, and herbaceous species diversity. Leaf litter significantly increased with distance from entry points and was greater in off-trail control plots than trail (trampled) plots. Plant cover showed the reverse trend by being greater in trail plots than controls. Leaf litter and plant cover were also significantly correlated with canopy, indicating environmental influence. However, Carex planostachys Kunze, the most successful plant on the trails, was equally prevalent in trail and control plots, demonstrating tolerance to both trampling and shade. Herbaceous species diversity was greater in trail plots and beginning stations than in control plots or trail end stations. Weedy annuals contributed the most to diversity in the autumn whereas native perennials were most important in the spring. Trampling and trailside vegetation each influenced trail width more than slope or soil type. Trails were wide near entry points except where dense vegetation confined hikers to a narrow path. In general, the nature of trail-border vegetation (trees, shrubs) was influential in controlling leaf litter, light, and hiker traffic patterns.
Insulin versus glipizide treatment in patients with non-insulin-dependent diabetes mellitus: Effects on blood pressure and glucose tolerance

Insulin resistance that exists in patients with essential hypertension and in those with non-insulin-dependent diabetes mellitus (NIDDM) may be the common denominator for the impaired glucose homeostasis and elevated blood pressure (BP) levels in patients with NIDDM. Therefore, treatment that improves insulin action may also improve BP levels. Consequently, a four-phase (glipizide υ insulin) cross-over design study was conducted to determine a better effect of glipizide treatment on insulin sensitivity and the effect this has on BP in 19 NIDDM patients. Patients were subjected to 1 month of diet only (phase I) followed by 3 months of glipizide treatment (phase II), then an additional 1 month of diet only (phase III), and finally 3 months of insulin treatment (phase IV). At the end of phases I, II, and IV oral glucose tolerance tests (OGTT) were performed and plasma glucose, insulin, and C-peptide levels were analyzed. Fasting plasma glucose, insulin, total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol and triglycerides, glycated hemoglobin, fructosamine, and 2-h postprandial plasma glucose were also analyzed at each phase. Supine and sitting BP levels and body weights were determined biweekly during the study. With the exception of higher plasma insulin and C-peptide levels during the OGTT (area under the curve) in phase IV (insulin) υ phase II (glipizide) (both P
13C INEPT Diffusion-Ordered NMR Spectroscopy (DOSY) with Internal References

13C INEPT Diffusion-ordered NMR spectroscopy (DOSY) with an internal reference system was developed to study the aggregation state of THF-solvated LDA dimeric complex. Six components are clearly identified in the diffusion dimension, and their DOSY-generated 13C INEPT spectrum slices agree extremely well with their respective INEPT spectra. The correlation between log D and log FW of the linear least-squares fit to reference points of all components is exceptionally high: (r = 0.9985).
The Style of Reading and Reading in Style

Adult read aloud book activities, including literature selections, have significant impact on children’s language learning opportunities. The style in which books are orally shared with children is also important. Detailed examination of adult-child book reading conversations has demonstrated a variety of teaching and learning approaches in the empirical and popular literature. Three of these approaches are included in this article: didactic-interactional, co-construction, and performance-oriented styles (Dickinson & Smith, 2004). Ten children’s books are reviewed and recommended.