cssi/SciSciGPT-SciSciNet huggingface dataset:
Improving skills development in residency using a deliberate-practice and learner-centered model.

Objectives/Hypothesis Work-hour restrictions, increased workload, and subjective assessment of competency are major threats to the efficacy of the traditional apprenticeship model of surgical training in modern surgical practice. In response, medical educators are developing time- and resource-efficient competency-based models of surgical training. The purpose of our project was to develop, implement, and measure the outcomes of such objective and structured programs in otolaryngology. We also investigated factors affecting the learning curve, especially deliberate practice, formative feedback, and learners' autonomy. Study Design Prospective, longitudinal study. Methods To measure the surgical skills of residents, we first developed and tested objective tools for otolaryngology procedures. Based on these instruments, we identified milestones of the procedures. Training on a virtual-reality simulator was validated to shorten the learning curve. We also studied a learner-centered approach of training, factors affecting the learning curve, and barriers to a competency-based model. Results The objective tools were found to be a feasible, reliable, and valid opportunity for measuring competency in both the laboratory and operating room. With the formative assessment from these tools, residents had a remediation target to be achieved by deliberate practice. The milestones helped identify the threshold of competency, and deliberate practice on the simulator gave an opportunity for improving skills. The learner-centered approach allowed flexibility and personalized learning by shifting the responsibility of the learning process to the learners. Conclusion The competency-based model of residency, based on the principles of deliberate practice and a learner-centered approach, is a feasible model of residency training that allows development of competent surgeons and hence improves patient outcomes. Despite these advantages, challenges to this model require a concerted effort to overcome and fully implement these principles of training beyond just technical skills, ultimately creating well-rounded medical professionals and leaders in the surgical field. Level of Evidence N/A. Laryngoscope, 125:S1–S14, 2015
A tracking controller for for a class of smooth nonlinear systems

In this paper, preliminary results on a feedforward tracking controller for smooth nonlinear systems is presented. The system is linearized first around a nominal trajectory, and a feedforward controller is designed for the linearized system. Then the feedforward gains are readjusted to ensure zero steady state error. The new gains are given in the form of a lookup table. For a ramp reference function, the new gains are given as a vector function of the reference input and its derivative, or, equivalently as a function of the reference input and its delayed value. Only ramp reference input is considered in the paper. The extension to higher order reference functions is cumbersome but straightforward. >
Heteromers of μ-δ opioid receptors: new pharmacology and novel therapeutic possibilities

Several studies suggest that heteromerization between μ (MOP) and δ (DOP) opioid receptors modulates the signalling properties of the individual receptors. For example, whereas activation of MOP receptors by an agonist induces G protein-mediated signalling, the same agonist induces β-arrestin-mediated signalling in the context of the MOP-DOP receptor heteromer. Moreover, heteromer-mediated signalling is allosterically modulated by a combination of MOP and DOP receptor ligands. This has implications in analgesia given that morphine-induced antinociception can be potentiated by DOP receptor ligands. Recently reagents selectively targeting the MOP-DOP receptor heteromer such as bivalent ligands, antibodies or membrane permeable peptides have been generated; these reagents are enabling studies to elucidate the contribution of endogenously expressed heteromers to analgesia as well as to the development of side-effects associated with chronic opioid use. Recent advances in drug screening technology have led to the identification of a MOP-DOP receptor heteromer-biased agonist that activates both G protein-mediated and β-arrestin-mediated signalling. Moreover, this heteromer-biased agonist exhibits potent antinociceptive activity but with reduced side-effects, suggesting that ligands targeting the MOP-DOP receptor heteromer form a basis for the development of novel therapeutics for the treatment of pain. In this review, we summarize findings regarding the biological and functional characteristics of the MOP-DOP receptor heteromer and the in vitro and in vivo properties of heteromer-selective ligands. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2
Nest-Specific DNA Fingerprints of Smallmouth Bass in Lake Opeongo, Ontario

Abstract Methods of DNA fingerprinting were employed to search for nest-specific markers in the population of smallmouth bass Micropterus dolomieu in Lake Opeongo, Ontario. Banding patterns produced from combinations of six restriction endonucleases and seven DNA fingerprint probes were evaluated. Each enzyme and probe combination detected very few polymorphic loci among fry from the same nest. However, comparisons of fingerprints between fry from different nests revealed significant differences in banding patterns, indicating that each nest had a unique fingerprint. Fry from 15 nests in the Jones Bay area of the lake were fingerprinted by using the restriction enzyme Hae III and the probe (GACA)4. A double-blind test was conducted to determine the ability to assign an unknown fry correctly to its nest of origin and demonstrate that nestspecific fingerprints exist. All fry tested were assigned correctly to their nest of origin by visual comparison of their fingerprints with each of the nest fingerprints, ...
Religious beliefs, metaphysical beliefs, and historiography of science.

T HE MISSION assigned to me in this essay is to provide a "philosophical analysis" of the difference between religious and metaphysical beliefs-of how (or, if the chips so fall, whether) we should draw this distinction. The task is conceptual, but the underlying motivation is historiographical. By reflecting on how we draw this distinction, my hope is to see how history of science may better illuminate the distinctive role of religious beliefs in past science. The essay has four parts. Part I considers some issues raised by recent historians of science which need to be taken seriously if a philosophical analysis is to have any relevance to working historians. In particular, an analysis must help us to avoid a whiggish "essentialism" that imposes our own metacategories ("religion," "science," etc.) on the past; it must also help us to avoid "metaphysicalizing" religious beliefs (barbaric habits deserve barbaric names!) and so to illuminate how the conditioning effect of religious beliefs may differ from that of metaphysical beliefs (whose role has long been recognized). Turning, then, to the philosophical task, part II suggests that in delineating these categories, we must fertilize a Wittgensteinian familyresemblance approach with the epistemologist's distinction between beliefs qua 'believeds' (the content of the beliefs) and beliefs qua 'believings' (the acts of believing). Part III then uses some historical cases to illustrate how this approach might affect our process of classifying a belief as metaphysical, as religious, or as scientific. Finally, part IV suggests one way in which our vision of the nature of science needs to be broadened if we are to account for the roles that metaphysical and religious believings play within the scientific process.
Substance P modulates single-channel properties of neuronal nicotinic acetylcholine receptors

Substance P (SP) is present in avian sympathetic ganglia and accelerates the decay rate of acetylcholine (ACh)-evoked macroscopic currents in sympathetic neurons. We demonstrate here that SP modulates ACh-elicited single channels in a manner consistent with an enhancement of ACh receptor (AChR) desensitization. Furthermore, since AChR channel function was monitored in cell-attached patches with SP applied to the extra-patch membrane, the peptide must act via a second messenger mechanism. SP specifically decreases the net ACh-activated single-channel current across the patch membrane by decreasing both channel opening frequency and mean open time kinetics. These experiments demonstrate that a peptide can modulate neuronal AChR function by a second messenger mechanism.
Overcoming Hurdles to Independence in Groups

Summary Independence necessitates a choice of when to yield to group conformity pressure and when not to yield. Independence is therefore an active process of choice rather than just a failure to conform. To make independent judgments in groups requires that an individual overcome a number of impediments, or hurdles, such as risks of disapproval. An experiment was conducted with 65 male undergraduates, in five-man discussion groups considering proposed solutions to urban problems. A significant interaction effect on independence was found when there was no requirement for a majority decision and positive feedback about the accuracy of their judgments was given.
Asbestos: world concern, involvement and culpability

The general population is exposed to asbestos fibers stemming from a massive number of consumer products and from environmental pollution. Asbestos bodies are present in the lungs of many urban dwellers who do not work with the mineral. Heavy occupational exposure to asbestos is known to cause asbestosis, pleural calcification, pleural plaques, lung cancer, and pleural and peritoneal mesotheliomas. The ingestion of asbestos fibers may increase the risk of gastrointestinal tract cancer. At the present time, little is known about the hazards of chronic low‐level exposure to asbestos. However, the use of asbestos fibers should be curtailed whenever possible, more pathogenicity data should be collected and evaluated, and the health risk to the general public should be reassessed and updated with progressing research.
Laboratory criteria for the adequacy of treatment and significance of blood levels.

(1970). Laboratory Criteria for the Adequacy of Treatment and Significance of Blood Levels. Clinical Toxicology: Vol. 3, No. 4, pp. 541-549.
In vivo and in vitro dermal penetration of 2,4,5,2',4',5'-hexachlorobiphenyl in young and adult rats

Penetration of 2,4,5,2',4',5'-[14C]hexachlorobiphenyl (HCB) through skin of young (33 days) and adult (82 days) female Fischer 344 rats was determined in vivo and by two in vitro methods. In vivo dermal penetration at 120 hr was 45% in young and 43% in adults. At 72 hr in vivo dermal penetration was 35% in young and 26% in adults compared to 1.5% for young and 1.0% for adult as measured with a continuous flow in vitro system and 2.9% for young and 1.9% for adults as measured with a static in vitro system. Most of the dermally absorbed HCB remained in the body as only 4.9 and 2.6% of that absorbed was excreted by young and adult rats, respectively, at the end of 120 hr. Significant differences in dermal penetration and kinetics of HCB between young and adult female rats were observed. The elimination of HCB-derived material was approximately six times higher in feces than in urine. A physiological pharmacokinetic model was fitted to the organ and tissue radioactivity distribution data. Parameters in the model determined from dermal dosing of female Fischer 344 rats were in reasonable agreement with those reported in the literature for adult male Sprague-Dawley rats (iv dose). The rat constant for dermal penetration was 0.83 x 10(-4) min-1 for adults and 0.96 x 10(-4)min-1 for young. The delay or lag time parameter for dermal penetration was 4.4 hr in adults and 1.1 hr in young.
Cholinergic and noncholinergic tegmental pedunculopontine projection neurons in rats revealed by intracellular labeling

Morphological features of rat pedunculopontine projection neurons were investigated in in vitro preparation by using intracellular labeling with biocytin combined with choline acetyltransferase (ChAT) immunohistochemistry. These neurons were classified into two types (Type I and II), based on their electrical membrane properties: Type I had low-threshold Ca2+ spikes, and Type II had A-current. All Type I neurons (n = 17) were ChAT immunonegative (ChAT-). Type II neurons were either ChAT immunopositive (ChAT+; n = 49) or ChAT- (n = 20). In terms of topography in the tegmental pedunculopontine nucleus (PPN), Type I neurons were dispersed throughout the extent of the nucleus, whereas Type II neurons tended to be located more in the rostral and middle sections. Both Type I and II neurons consisted of small (long axis 35 microns) cells. The small cells were round or oval; medium cells were round, triangular, or fusiform; and the large cells were primarily fusiform in shape. In terms of the soma size, there was a difference in Type I (15-38 microns) and Type II (11-50 microns) neurons, but no significant difference was found between Type II ChAT+ and ChAT- cells. Both types of neurons had three to six primary dendrites, but the dendritic field was more prominent in Type II neurons. Most of the axons originated from one of the primary dendrites, which gave off axon collaterals, some of which projected out of the nucleus. The intrinsic collaterals were thin and branched partly within the dendritic field of the parent cell. The extrinsic collaterals were thicker and could be grouped into three categories: 1) collaterals arborizing in the substantia nigra; 2) collaterals ascending mainly toward the thalamus, pretectal, and tectal area; and 3) collaterals descending toward the mesencephalic and/or pontine reticular formation. It was noted that the collaterals of both ChAT+ and ChAT-neurons were traced into the substantia nigra. There was no significant difference in antidromic latencies between Type I (m = 1.47 msec) and Type II (m = 1.36 msec) neurons following electrical stimulation of the substantia nigra.
Induced axial chirality in the biphenyl core of the cα-tetrasubstituted α-amino acid residue Bip and subsequent propagation of chirality in (Bip)n/Val oligopeptides

In the dipeptides Boc-Bip-L-Val-OMe and Boc-Bip-D-Val-OMe, an induced axial chirality in the biphenyl core of the Bip residue, a conformationally labile, proatropoisomeric Cα,α-disubstituted glycine, was observed by electronic CD and 1H NMR. Chiral induction is significantly higher when the Val residue is located at the C-terminal position of Bip. An outstanding phenomenon of propagation of chirality was demonstrated to occur in the related 310-helical -(Bip)n-L-Val (n = 2−6) oligopeptides by CD and vibrational CD techniques.
The effect of Marcaine on muscle and non-muscle cells in vitro.

The effect of the local anaesthetic Marcaine on muscle and non-muscle cell types was examined using an in vitro assay. Each of the cell types examined (myotubes, myoblasts, fibroblasts and liver parenchyma) expressed morphological alterations when incubated in Marcaine-medium. Myotubes were the most sensitive of the cells studied and exhibited several pronounced membrane structural changes after short incubation periods in Marcaine-medium. The toxic effects of Marcaine were irreversible and the myotubes continued to degenerate despite being placed in fresh medium. Myo-blasts and non-muscle cells, however, demonstrated a rapid recovery when removed from the Marcaine-medium. Since Marcaine is thought to compete with Ca++ for specific sites on cell membranes, it is proposed that the differential effects which were observed are dependent upon the level of calcium related activities being carried out by the cells.
Thermomechanical analysis of a user filter assembly for undulator/wiggler operations at the Advanced Photon Source

This paper reports a thermo-mechanical study of a beamline filter for undulator/wiggler operations.It is deployed in conjunction with the current commissioning window assembly on the APS insertion device (ID) front ends. The beamline filter at the APS will eventually be used in windowless operations also. Hence survival and reasonable life expectancy of the filters under intense ID heat flux are crucial to the beamline operations. To accommodate various user requirements, the filter is configured to be a multi- choice type and 'smart' to a low only those filter combinations that will be safe to operate with a given ring current and beamline insertion device gap. However, this paper addresses only the thermo-mechanical analysis of individual filter integrity and safety in all combinations possible. The current filter design is configured to have four filter frames in a cascade with each frame holding five filters. This allows a potential 625 total filter combinations. Thermal analysis for all of these combinations becomes a mammoth task considering the desired choices for filter materials, filter thicknesses, undulator gaps, and the beam currents. The paper addresses how this difficult task has been reduced to a reasonable effort and computational level. Results from thermo-mechanical analyses of the filter combinations are presented both in tabular and graphical format.
Taurodontism, diminished root formation, and microcephalic dwarfism.

S ir Arthur Keith’ coined the term taurodontism to describe a variation in form of multirooted teeth in which the body of the tooth was enlarged and the roots were reduced in size. Keith encountered this trait in remains of Neanderthal man and noted the contrast from cynodont teeth of modern Caucasian man. Cynodont teeth have relatively small pulp chambers, they are set low in the crown with a constriction in outline form of the chambers at about the cementoenamel junction, and the distance from the bifurcation or trifurcation of the roots to the cementoenamel junction is less than the occlusocervical distance. In contrast, taurodont teeth have pulp chambers in which the bifurcation or trifurcation is displaced apically, so that the chamber has a greater apico-occlusal height than in eynodont teeth and there is no constriction at the level of the cementoenamel junction. The distance from the bifurcation or trifurcation of the roots to the cementoenamel junction is greater than the occlusocervical distance.2s 3 In contrast, diminished root formation, a rare condition, may be seen in the third molar region and mandibular premolar area as a variation from the norm.4 It may be the central feature of dentinal dysplasia.,” or it may be the result of idiopathic hypoparathyroidism6 or exposure to x-radiation during periods of odontogenesis.i-14 Diminished roots have been noted in thalassemia,15 and they have been reported in the maxillary anterior region as a frequent occurrence in the Japanese.lg Following is a case with the features of taurodontism in the posterior dentition, diminished anterior root formation, and microcephaly with somatic dwarfism.
The pathogenesis of bacterial keratitis: studies with Pseudomonas aeruginosa

Bacterial keratitis is a sight-threatening corneal disease that is most commonly associated with the extended wear of soft contact lenses. Over the past decade, we have investigated the pathogenesis of infectious keratitis involving the opportunistic pathogen Pseudomonas aeruginosa. Our research has focused on understanding the respective roles of bacteria and host in the establishment of this infection. Here, we provide a current perspective on P. aeruginosa keratitis, reviewing some of the research developments that have helped shape our views on the mechanisms by which pathogen and host response cause corneal disease. P. aeruginosa may provide a model for the pathogenesis of bacterial keratitis and help further elucidate the complex array of host factors that normally protect the cornea from infectious agents.
Thermodynamic properties of the ternary Na-Bi-Te and K-Bi-Te alloys by electromotive force measurements with an alumina solid electrolyte

Abstract Activity coefficients for alkali metal in the Na-Bi-Te and K-Bi-Te alloys were measured up to approximately 60 atom percent ( a o ) alkali metal at 600°C. A coulometric titration technique was used to electrochemically generate the alkali metal in Bi-Te with a solid electrolyte consisting of either Na-βAl2O3 or potassium substituted βAl2O3. The results indicated that the Na-based alloys were structurally less ordered than the K-based alloys and that the presence of Te has a profound exosolution effect on these alkali metal based alloys.
Heparin as an adjuvant to thrombolytic therapy in acute myocardial infarction

For the treatment of acute myocardial infarction, heparin has been a topic of continuing debate for the past four decades. After review of the available data, the American College of Cardiology/American Heart Association Guidelines for the Early Management of Patients with Acute Myocardial Infarction, published in 1990, recommended intravenous heparin administration together or immediately after thrombolytic therapy to maintain the activated partial thromboplastin time approximately 1.5 to 2.0 times the control value for 24 to 72 hours. Over the past five years, with the proven benefits or thrombolytic therapy and antiplatelet therapy, investigators have been in search of the ideal thrombolytic agent as well as the best adjunctive antithrombotic strategy. We review a number of angiographic patency trials as well as the major thrombolytic mortality reduction trials in which adjunctive heparin therapy was directly assessed. These trials established the need for intravenous heparin administration with tissue plasminogen activator, but, on the other hand, do not substantiate the need for either subcutaneous or intravenous heparin use with streptokinase. New data from a large scale trial emphasizes the importance of maintaining the aPTT in the 55-70 second range to prevent bleeding complications and optimize clinical outcomes.
Holographic optical element based single-mode hybrid fiber optic interferometer for realizing zero-order fringe

A holographic optical element (HOE) based single-mode hybrid fiber optic interferometer for realizing the zero-order fringe is described. The HOE proposed and used integrates the actions of a beam combiner and a lens, and endows the interferometer with high tolerance for repositioning errors. The proposed method is simple and offers advantages such as the elimination of in situ processing for the hologram.
Power, Globalization, and the End of the Cold War: Reevaluating a Landmark Case for Ideas

The end of the Cold War has become a case study of major importance for scholars of international relations for numerous reasons. Not least among these is that it helped spark a renaissance in the study of ideas in the aeld and contributed to the rise of constructivism as a major theoretical school in the 1990s.1 It has also proven to be a rich case for developing new arguments inspired by constructivist thinking, as well as for extending standard models drawn from cognitive or social psychology and organization theory concerning how ideas shape strategic behavior. The result of this scholarly effort is a rich and diverse literature that advances numerous models of how norms, culture, identity, trust, persuasion, learning, demonstration effects, transnational conceptual oows, intellectual entrepreneurship, socialization, and many other ideational processes inouenced the dramatic ending of the superpower rivalry. Indeed, it is difacult to identify another case that has generated as large and varied a literature devoted to exploring how ideas inouence international relations.2 Power, Globalization, and the End of the Cold War
Digit pipelined processors

Digit serial data transmission can be used to an advantage in the design of special purpose processors where communication issues dominate and where digit pipelining can be used to maintain high data rates. VLSI signal processing applications are one such problem domain. We have developed a family of VLSI components that have digit serial transmission and that can be pipelined at the digit level. These components can be used to construct VLSI processors that are especially suited to signal processing applications. One such particularly attractive processor is a structure we call the arithmetic cube. The arithmetic cube can be programmed to solve linear transformations such as convolutions and DFTs, and has nearest neighbor interconnects, regular layout, simple control, and a limited number of interconnections. Regular layout and simple control derive naturally from the algorithms on which the processor is based. Long wires are eliminated by the nearest neighbor interconnect. High throughput can be achieved by pipelining the processor at the digit level. The arithmetic cube is programmable in the problem size n; once implemented for a certain size N, smaller problems can be solved on the same implementation without a loss in performance. In addition, the architecture extends to larger N in a regular and automatic fashion.
The reaction of magnesium with hydrogen chloride and ammonia

Abstract Anhydrous magnesium chloride has been obtained as a white, powdered material with a purity of 99·5–99·9 per cent as calculated by the Cl:Mg ratio. The procedure involves the intermittent reaction between sublimed magnesium chips and anhydrous hydrogen chloride and ammonia gases over a 6–8 hr period. The mechanism suggested for this reaction involves an initial “onium” type reaction in an ammonia atmosphere resulting in the formation of the stable ammoniate MgCl2·1NH3 and a subsequent decomposition of the ammoniate in a hydrogen chloride atmosphere yielding the desired product.
False positive appendicitis on bedside ultrasound.

Author(s): Canders, Caleb P.; Brown, Angela J.; Chiem, Alan T. | Abstract: NA (Image report)
Isolation and photosynthetic characteristics of mesophyll cells from developing leaves of soybean

Mesophyll cells were isolated from developing sink leaves (25 to 30 mm in length) of soybean, Glycine max (L.) Merr. cv. Will. Leaf strips were incubated for two h in a buffered medium containing osmoticum and 0.2% Pectolyase Y-23. Gently stirring the leaf strips released from 7 to 16% of the total leaf mesophyll cells. Other pectinase enzymes, effective in releasing cells from mature source leaves (70 to 75 mm in length), did not release cells from sink leaves. Sink and source cell preparations were about 50 and 95% intact, respectively, based on the exclusion of Evans Blue dye. Intact cells could not be separated from broken cells on Ficoll or metrizamide density gradients. Total protein and catalase, glyceraldehyde-3-phosphate dehydrogenase, glycolate oxidase, phosphoenolpyruvate carboxylase, and ribulose 1,5-bisphosphate carboxylase activities on a chlorophyll basis were about 50% lower in sink mesophyll cells than in sink leaf homogenates indicating that broken sink cells lost soluble protein to the medium. Source cells and source leaf homogenates had comparable amounts of protein and enzymatic activities. Enzymatic activities on a chlorophyll basis were similar in source and sink leaves with the exception of phosphenolpyruvate carboxylase, which was two times higher in sink leaves. This enzyme was also exceptionally low in source and sink cells being only 61 and 23%, respectively, of whole leaf activities. Sink cell rates of 14CO2 fixation were only 7% of source cell rates and sink cells did not show light-dependent O2 evolution. Both cell preparations had photosystem II activiteis which were comparable to rates of 14CO2 fixation at satuarating light and CO2 concentration. It was concluded that the reduced photosynthetic rate of sink cells was limited by the low photochemical capacity rather than a limitation of Calvin cycle enzymes.
A Critique of Exchange Rate Treatment in Agricultural Trade Models: Comment

The influence of the value of the dollar on developments in the U.S. farm sector is now widely recognized. Even so, considerable controversy remains over the magnitude of exchange rate effects on agriculture. While this is largely an issue of empirical measurement, there is also a broadly held perception that the conceptual discussion of these effects has been inadequate. In part, this is due to extensive discussion of these effects based on partial equilibrium, often single-market, analysis. The single-market framework imposes tight constraints on exchange rate impacts on equilibrium prices and export quantities. In particular, in a single-market partial equilibrium model, the exchange rate elasticity of price is always less than unity in absolute value.'1 In an important paper Chambers and Just extended the single-market partial equilibrium approach to account for the effects of an exchange rate realignment on all prices in an n-good economy. Their analysis remained partial in the sense that the exchange rate was exogenous and income was held constant. Nevertheless, they concluded that potential cross-price effects in excess supply and excess demand functions make it inappropriate to restrict the exchange rate elasticity of any specific price to the closed interval [1, 0]. The purpose of this comment is to place the analysis of potential exchange rate effects in agricultural markets more firmly in the context of general equilibrium trade theory. The approach presented herein follows Krueger, Chipman (1974), and others in drawing a distinction between traded and nontraded goods. Then the crucial concept is the association of the real exchange rate and movements of disposable income between countries. The xchange rate-which affects the prices of traded goods vis-a-vis the prices of nontraded goods-and relative prices among traded goods adjust jointly to accommodate the equilibrium induced by a trade imbalance. The income movement between countri s is key because it creates a link between exchange rate and price changes that is not considred in a partial equilibrium analysis. Explicit consideration of this link clarifies the role of the exchange rate in goods markets and provides a clearer rationale for the case of a percentage change in a price exceeding the percentage exchange rate realignment.
Elastic Moduli of Tin at the Superconducting Transition

A composite oscillator technique was used to measure the elastic moduli of tin in the normal and superconducting states. The experiments were performed on single crystals at about 50 kc/sec. A difference in moduli was observed, indicating that the velocity of sound is less in the superconducting than in the normal state. At 3.7\ifmmode^\circ\else\textdegree\fi{}K the relative change at the superconducting transition is about 4 parts in ${10}^{6}$ for the longitudinal modulus ${S}_{11}$ and about 6 parts in ${10}^{6}$ for the torsional modulus, $2({S}_{44}+{S}_{66})$. These relative changes increase with decreasing temperature. At room temperature, the adiabatic modulus ${S}_{11}$ was found to be 1.55\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}12}$ ${\mathrm{cm}}^{2}$/dyne, and $2({S}_{44}+{S}_{66})$ was 9.4\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}12}$ ${\mathrm{cm}}^{2}$/dyne.
The control of sexual development in Drosophila melanogaster: genetic and molecular analysis of a genetic regulatory hierarchy — a minireview *

Genetic analyses of mutants affecting the sexual development of the fruitfly, Drosophila melanogaster, have led to a genetic model that describes how the wild-type genes interact with one another as parts of a single regulatory pathway. More recent molecular studies on some of these sex differentiation regulatory genes have lent support to this genetic model, and have defined the molecular nature of some of these genetic interactions. One surprising feature of the regulatory hierarchy to emerge from these molecular studies is that many of the sex-specific genetic switches in this pathway are not transcriptional regulation events but, rather, are based on sex-specific alternative RNA processing events (pre-mRNA splicing and/or polyadenylation site selection).
46 Near shore sediment diatoms of the great lakes and their use as biological indicators

The great Lakes Environmental Indicators (GLEI) project, funded through the U.S. EPA, has set goals to identify taxa that will be useful in determining ecosystem integrity in near shore waters of the Great Lakes ecosystem. Through the development of biological indices, rapid, consistent, and inexpensive methods of bioassessment of the Great Lakes can be utilized. This particular study focuses on the use of near shore sediment diatoms. Sediment core collection and water sampling and analysis were completed at nearly 100 stratified randomly selected sites across all five of the Great Lakes. Canonical correspondence analysis (CCA) indicated a gradient of water quality throughout the Great Lakes. Lake Superior was determined to have the lowest concentration of measured nutrients, while Lake Erie and Lake Ontario had the highest. Lake Michigan and Lake Huron shared a similar transitional water quality. Although analyses and indices have been developed thus far, GLEI is in its third year of a 4-year schedule.
Protein Dispersibility Index (PDI) as a Quality Control Measure for Soy Flour Used in Brown Trout Starter Feed

Abstract Protein dispersibility index (PDI), the percent of total protein that disperses in water under standard conditions and which is correlated with the amount of heat to which soy flour is exposed during production, was used to measure the adequacy of processing for soy flour used in starter diets of brown trout (Salmo trutta) fry for a 112-day period. Fish fed diets with soy flour, 15% of diet by weight, with a PDI of 11 or 20 had a greater weight gain than fish fed diets with soy flour with a PDI of 70 or 88 and a lower mortality rate than fish fed the diet with soy flour with a PDI of 88. Feed conversion (grams feed/grams gain) was best for fish fed the diet with soy flour with a PDI of 20, intermediate for fish fed diets with soy flour with a PDI of 11 or 70, and worst for fish fed the diet with soy flour with a PDI of 88. PDI values are a useful measurement of the nutritional value of soy flours in trout starter diets.
BLOOD GLUCOSE AND LIVER GLYCOGEN LEVELS IN GLUCAGON-TREATED CHICK EMBRYOS.

Abstract The capabilities of chick embryos incubated 6.0–18.0 days to respond to glucagon and recover from its hyperglycemic effect have been examined. A single addition of glucagon solution (Lilly) at a dosage level of 150 or 300 μg was placed on the chorioallantois of 6.0-, 8.0-, 10.0-, 12.0-, 14.0-, and 16.0-day embryos. Blood glucose samples were collected from days 8.0 through 18.0 while livers were procured from embryos sacrificed from days 6.0 through 18.0 of incubation. Liver glycogen levels in glucagon-treated chick embryos indicate that the chick is capable of responding to the hormone as early as day 6 of incubation. Both blood glucose and liver glycogen levels in treated chick embryos indicate that the magnitude and duration of response varies with the age of the embryo. The recovery of blood glucose and liver glycogen levels in the 6.0–10.0-day incubation interval demonstrates that the early chick does have the capacity to regulate blood glucose as well as liver glycogen levels to normal after the addition of a hormonal “hyperglycemic agent.”
The Origin of Lake Basins

I WISH to draw the attention of your correspondents, Messrs Aitken and Tarr, to p. 94 of the Geological Magazine, vol. iv. 1876, in regard to the manner in which, in all probability, the greater number of the lakes in British North America were formed. There are, however, doubtless many other causes by which lake basins have been formed. The object of my notice was simply to point out that the ice need not be supposed to have exerted any extraordinary or abnormal influence in scooping out rock basins which have subsequently become lakes.
Characterization of 3He area sensitive proportional counters at IPNS for SANS applications

The Small Angle Diffractometer (SAD) at the Intense Pulsed Neutron Source (IPNS) utilizes a 20 X 20 cm2 Borkowski-Kopp type 3He position sensitive detector (PSD) which has reliably performed small-angle neutron scattering experiments for more than a decade. The pulsed-source based SAD employs a small, but fixed, sample-to-detector distance and a pulsed polychromatic neutron beam. The neutron energies are resolved through time-of- flight (TOF) measurements so that a much wider range of momentum transfer is probed in a single measurement compared to the range of spectrometers using monochromatic incident beams. However, the pulsed source requires a short sample-to-detector distance so that the detector covers a large solid angle, but with lower angular resolution, and this situation puts stringent demands on the spatial resolution of the detector. Previously, nonlinearities in the position encoding of detected neutrons required that the outer channels of the detector, representing 40% of the detector area, be discarded. This paper presents a technique to characterize both the position encoding and the position resolution of the entire detector so that the whole detector can be used for SANS measurements.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
A comparison of calcium binding in Callinectes sapidus premolt and postmolt cuticle homogenates: implications for regulation of biomineralization.

Cuticle tissue homogenates (CTHs) fromCallinectes sapidus premolt cuticle bound approximately 367% more Ca2+ ions than did those from the postmolt cuticle. ThepH-stat assay which was used to comparein vitro CaCO3 nucleation times confirmed that the premolt CTHs had greater inhibitory activity than did the postmolt CTHs. This inhibitory activity was indicated by CaCO3 nucleation times in excess of control values. Premolt nucleation times exceeded those of postmolt samples by approximately 340%. A positive correlation was observed between Ca2+ binding and calcification inhibitory activity for both premolt and postmolt CTHs. Heat pretreatment of CTHs at 70°C for a 24-hr period had no significant effect on their Ca2+ binding. However, this heat pretreatment decreased their calcification inhibitory activity. Pretreatment of CTHs with Ca2+ diminished their calcification inhibitory activity. These results are consistent with a mechanism for inhibition of biocalcification by these proteins which involves their initial reversible binding to nascent calcite nuclei growth steps and kinks, rather than theirin vivo interaction with free Ca2+ ions in solution.
Peptide—Carrier Interaction: Induction of Liposome Fusion and Aggregation by Insulin

As the roles of peptidic agents in therapy expand, the need for gaining the knowledge for formulating peptides and/or polypeptides becomes increasingly urgent. In an attempt to study various approaches to formulating peptidic agents for therapeutic applications, we investigated the interactions between drug carriers and peptides, using liposomes and insulin as a model. The fusion and aggregation properties of dipalmitoylphosphatidylcholine (DPPC) small, unilamellar liposomes, on the binding of insulin was studied by the techniques of resonance energy transfer of fluorescent labeled lipids, electron microscopy, and right-angle scattering. Within 1 h of adding insulin to DPPC liposomes at 25° C, the average size of the liposomes increased from 239 to 361 A in diameter. There was no further increase in the size of the liposomes after the fused lipsosomes reached this size. However, the aggregation of the fused liposomes continued to increase for several hours after the insulin-induced fusion stopped. Our results suggest that insulin induces the aggregation of newly fused liposomes, when the temperature is below the gel → liquid crystalline phase-transition temperature (Tc) of the liposomes. The aggregation of fused liposomes is markedly affected by not only the zinc content of insulin but also the pH and ionic strength of the solution. The results of the present study demonstrate that an amphyphilic molecule, such as insulin, could induce the fusion of liposomes via hydrophobic interaction and facilitate liposome aggregation via hydrophilic interaction. Thus, when entrapping insulin by small, unilamellar liposomes, care should be taken to avoid fusion and aggregation.
Verification of tracking servo signal simulation from scanning tunneling microscope surface profiles

Well-defined track crossing signals are essential for the laser tracking servo systems to follow radial runout. We developed an approach to verify Fourier Optics calculation of the track crossing signals from 3D surface profiles measured by Scanning Tunneling Microscopy (STM) and also by measuring the actual tracking servo groove signals from the substrate on an optical disk tester. Nearly quantitative agreement between the tracking signals calculated from the measured STM profiles and those measured by the optical disk tester was demonstrated on grooved glass disk substrates with a 1.6 micrometers pitch and nominal groove depths of 20, 40, and 70 nm, and on photopolymer on glass substrates with track pitches of 1.6, 1.4, 1.2, 1.0, 0.8 and 0.6 micrometers and a groove depth of 67 nm. Injection molded polycarbonate substrates made with high and low mold temperature showed poor replication at the lower mold temperature. The servo signals reflected the degraded servo groove performance due to the poor servo groove replication at the lower mold temperature.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Synthesis, characterization, and aqueous chemistry of cytotoxic Au(III) polypyridyl complexes

Abstract This work reports the synthesis, characterization, and aqueous chemistry of a series of cytotoxic [Au(polypyridyl)Cl2]PF6 complexes {(where polypyridyl = dipyrido[3,2-f:2′,3′-h] quinoxaline (DPQ), dipyrido[3,2-a:2′,3′-c] phenazine (DPPZ) and dipyrido[3,2-a:2′,3′-c](6,7,8,9-tetrahydro) phenazine (DPQC))}. The crystal structure of [Au(DPQ)Cl2]PF6 was determined as example of the series and exhibits the anticipated square planar geometry common for d8 coordination complexes. The crystals of the complex belong to the space group P21/n with a = 7.624(2) A, b = 18.274(5) A, c = 14.411(14) A, β = 98.03(3)°, and Z = 4. In 1H NMR studies of these compounds in the presence of aqueous buffer, all four complexes rapidly converted to the dihydroxy species [Au(polypyridyl)(OH)2] in a stepwise fashion. However, the [Au(polypyridyl)]3+ fragment believed to impart cytotoxicity in human ovarian cancer cell lines (A2780) remained intact and appeared stable for days. It was also noted that these Au(III) complexes were readily reduced in the presence of the common biological reducing agents, reduced glutathione and sodium ascorbate. How solution and redox stability may affect the biological activity of these novel Au(III) complexes is discussed.
Passive approach of controlling twist in composite tilt-rotor blades

This paper examines the static and dynamic behavior of initially twisted composite spars for tilt-rotor applications, as well as documenting the fabrication of five pairs of initially twisted advanced composite single-cell spars. Spars having five different material stacking sequences were fabricated for a given geometric and pretwist definition so as to determine the maximum and minimum spar untwist for a given unit load (stiffness approach) and a given maximum load (strength approach). Analytical static stiffness and strength results are presented using a detailed shell-type finite element model, along with a two-dimensional elasticity approach to show how the maximum elastic beam untwist varies as a function of the composite spar geometric parameters and material ply orientation. Experimentally measured free-free and cantilevered natural frequencies and damping levels of the spars are presented along with a correlation to a highly refined shell-type finite element model. These vibration results reveal that both ply angle orientation and initial twist significantly alter the spar natural frequencies, where the effects are largest in the higher bending and torsion modes. Damping level changes were clearly observed with ply orientation changes (i.e. increases in extension-torsion coupling produced bending mode damping increases and torsion mode damping decreases).
An accessory protein enhances both DNA binding and activity of DNA polymerase α isolated from normal, but not transformed, human fibroblasts

DNA polymerase alpha/primase (pol alpha) isolated from fibroblasts established from a 66-year-old human donor (GM3529) exhibited decreased specific activity compared with pol alpha from either fetal-derived fibroblasts (WI38), or pSV3.neo-transformed GM3529 fibroblasts. The pol alpha specific activity decrease was correlated with a decreased proliferative capacity frequently seen in cells from aged donors. Pol alpha isolated from pSV3.neo-transformed GM3529 cells (GM3529T) exhibited a single isoform with about 10-fold higher specific activity than pol alpha from GM3529 cells. GM3529T pol alpha was immunoreactive with both anti-pol alpha and anti-SV40 large tumor antigen. Polymerases from GM3529 and GM3529T cells were treated with a pol alpha accessory protein, alpha AP, isolated from L1210 cells. Pol alpha from GM3529T cells showed no increase in activity in the presence of alpha AP, while pol alpha isolated from GM3529 cells exhibited about an 8-fold increase in activity after treatment with alpha AP. Double stranded SV40 DNA containing multiple ori sequences exhibited a greater decrease in electrophoretic mobility in the presence of GM3529T pol alpha than when treated with GM3529 pol alpha. In the presence of pol alpha from either GM35229 or GM3529T cells SV40 dsDNA exhibited a decrease in electrophoretic mobility, and in each instance addition of alpha AP resulted in an even greater decrease in DNA mobility. These data indicate that alpha AP increased pol alpha binding to SV40 dsDNA, or that alpha AP bound the DNA in addition to previously bound pol alpha. GM3529 pol alpha also bound non-specific, non-SV40, dsDNA, whereas GM3529T pol alpha with associated TAg did not bind the non-viral dsDNA unless alpha AP was added to the preparation. While not all human diploid fibroblast cell lines derived from aged human donors necessarily exhibit decreased proliferative capacity compared with cells from young donors, decreased specific activity associated with a decline in cellular DNA synthesis is typical of pol alpha from cells derived from aged human donors. We suggest that a decrease in endogenous alpha AP interaction with pol alpha may account, in part, for the loss of DNA binding affinity and specific activity of pol alpha from GM3529 cells derived from an aged donor.
Growth Form and Distribution of Vine Maple (Acer Cirinatum) on Marys Peak, Western Oregon

Vine maple growth form and distribution differ between plant communities. Most stems are erect in the high elevation Pseudotsuga/Acer/Gaultheria community, whereas crown spread, bryophyte cover, height, and diameter attain a maximum in the Pseudotsuga/Acer/Polystichum community. Layering is primarily responsible for the distribution of vine maple and can only occur where the stems become arched and contact the ground. On slopes exceeding 30% most stems lean down or across the slope. In some communities upslone movement of vine maple is restricted because of repeated fires and the step slope which limits layering. See full-text article at JSTOR