cssi/SciSciGPT-SciSciNet huggingface dataset:
Stresses in Towed Cables During Re-entry

Towed cables behind re-entry vehicles have been found to break progressively from the trailing end during early re-entry. An analysis of expected vibrational stresses due to periodic perturbations has been made, and this analysis has been used to estimate the variation of residual cable length with range through the atmosphere. Predictions of length variation are compared to measured values in the Naval Ordnance Laboratory 1000-ft Hypersonic Range and compare reasonably. The relative influence on cable stress and residual length are given for the various parameters of the cable and the towing body, and various methods are suggested for maximizing the length of cable to a prescribed altitude.
Accuracy of computed tomography findings in acute pericarditis.

Background:Acute pericarditis is a close clinical mimic of pulmonary embolism (PE) in the emergency department, and thus many of these patients are evaluated with chest computed tomography (CT).Purpose:To study whether CT findings can be diagnostic of acute pericarditis.Material and Methods:Using the electronic medical record, we retrospectively identified 46 cases of acute pericarditis and 46 control patients with pericardial effusions due to volume overload, all of whom underwent CT examination. Cases were reviewed by two blinded academic thoracic radiologists.Results:The majority, 67%, of the pericarditis cases were evaluated with PE-protocol CTs. Pericardial thickening/enhancement was the most accurate single parameter for pericarditis, with sensitivity of 54–59% and specificity of 91–96%.Conclusion:CT findings, while not sensitive for pericarditis, are diagnostic, with few false-positives. Radiologists should be attentive to pericardial thickening or enhancement on CT studies done for chest pain, as ...
Numerical simulations of counterstreaming plasmas and their relevance to interhemispheric flows

The collisionless expansion of counterstreaming plasmas has been studied by solving the self-consistent set of Vlasov and Poisson equations in one dimension. The motivation for the study is to elucidate some of the basic physical processes which may occur during the initial refilling of depleted flux tubes after a magnetic storm. The simulation geometry consisted of two high-density H+-O+-electron plasmas (conjugate ionospheres) separated by a low density H+-electron plasma (equatorial plasmasphere). The temporal evolution of the expanding plasmas and the electrostatic potential in the region between the two sources has the following characteristics. The initially minor H+ions rapidly flow out of the source regions, creating counterstreaming density shock fronts which propagate at the Sagdeev Mach number for ion acoustic shocks (M ∼1.6). However, the shocks are preceded by suprathermal forerunner ions, which are the first to fill the “equatorial” region. When the counterstreaming ion acoustic shocks collide, the density in the equatorial region becomes nearly a constant, twice the value of the density in the individual shocks. The electrostatic potential distribution from the source plasmas to the midpoint of the expansion region displays an interesting feature. A potential hill forms near the midpoint after the arrival of the main density shock fronts. This localized potential hill plays an important role in the thermalization of the ion streams and may occur in the equatorial plasmasphere after magnetic storms. The numerical simulations indicate that the ion beams in the counterstreaming plasmas are remarkably stable with respect to the ion acoustic instability, which is in agreement with the linear instability theory. However, in the presence of a magnetic field, the linear instability theory predicts that the counterstreaming suprathermal forerunner ions can excite ion cyclotron waves, which in turn can thermalize and trap the suprathermal forerunners. Such a mechanism may be operating in the equatorial plasmasphere shortly after magnetic storms.
Major Changes in American Airlines Flight Crew Training

During the last eight years, over 5000 pilots have completed transition training to B-747, DC-10, B-707, B-727, and BAG 1-11 aircraft at American Airlines' Flight Academy. These pilots have completed over 25,000 recurrent training cycles. All of these pilots have been trained in a manner that, initially, was revolutionary; yet the resulting trained crewmen, along with carefully prescribed and enforced operating procedures, has achieved a most excellent safety record in commercial aviation. The training techniques are described and illustrated. Critical operating procedures that are just as vital to safety are discussed. Training of flight crewmen can be more efficient and also can be of better quality. A systems approach to planning the whole training program, including line experience, is vital. The proper use of simulation is a key ingredient.
Delai Sam: social activism as contemporary art in the emerging discourse of DIY urbanism in Russia

Delai sam (do it yourself) is a deeply rooted phenomenon in Russian life. However, as a form of contemporary art, this phenomenon has taken on an activist tenor in post-socialist urban Russia. Founded in 2010, the Delai Sam Festival of Urban Actions represents a politicized approach to DIY urbanism in today’s Russia, in which artists, designers, activists and scholars are joining together to develop alternatives to official visions for the design and planning of their cities. This article critically examines the discourse of the first few Delai Sam festivals in Moscow and Saint Petersburg, and related urban interventions, to understand how these actions are both situated within their local context, and linked discursively to global trends in art and urban activism. DIY actions like Delai Sam open windows into the convergence of art and social activism, the aesthetic and the political, currently taking shape within the global city.
On the Third Wave of Democratization: A Synthesis and Evaluation of Recent Theory and Research

This article synthesizes significant findings of theoretical and empirical research on the third wave of democratization. It addresses a number of central questions. What changes have been taking place in the study of democracy and democratization over the past two decades? How have the concepts of democracy and democratization been redefined for a new generation of scholars oriented to action and advice? What developments in the measurement of the two concepts have been stimulated by the quickening pace of democratization? What has been learned about the dynamics of democratization itself? What mixes of democratic institutions and rules offer the “best” prospect for democratic consolidation? What kinds of strategies and tactics have been prescribed for encouraging democratic reforms in those countries that remain nondemocratic? What are the prospects for the third wave of democratization?
Arthrotomy approaches in the lower extremity

Abstract Surgical approach to the major joints of the lower extremity can be simplified and facilitated by (1) placement of skin incisions so that maximum subcutaneous tissue flexibility is assured, and (2) resection of the bone attachments of tendons and ligaments.
Growth and Characterization of Alternative Gate Dielectrics by Molecular-Beam Epitaxy

In this work, we have investigated conditions to grow epitaxial La2O3 and Sc2O3 thin films directly on (111) Si as well as epitaxial LaScO3 thin films on (100) Si using an alkaline earth oxide buffer layer. The films were structurally characterized by reflection high-energy electron diffraction (RHEED) during growth and four-circle x-ray diffraction (XRD) and high-resolution plan-view and cross-section TEM, including Z-contrast TEM after growth. The epitaxial La2O3 thin films grew with the following epitaxial relationship (0001) La2O3 // (111) Si La2O3 // [112] Si with 1 additional rotational twin variant. Sc2O3 thin films grew epitaxially with a cube-on-cube orientation relationship on (111) silicon. It was not possible to achieve epitaxial LaScO3 thin films without the use of an alkaline earth buffer layer. The epitaxial orientation relationship between the orthorhombic LaScO3 and the underlying Si was (101) LaScO3 // (001) Si and [010] LaScO3 // [110] Si.
Nuclear-cytoskeletal interactions: evidence for physical connections between the nucleus and cell periphery and their alteration by transformation.

The overall coordination of cell structure and function that results in gene expression requires a spatial and temporal precision that would be unobtainable in the absence of structural order within the cell. Cells contain extensive and elaborate three-dimensional skeletal networks that form integral structural components of the plasma membrane, cytoplasm, and nucleus. These skeletal networks form a dynamic tissue matrix and are composed of the nuclear matrix, cytoskeleton, and extracellular matrix. The tissue matrix is an interactive network which undergoes dynamic changes as cells move and change shape. Pathologists have long recognized cancer in pathologic specimens based on the altered morphology of tumor cells compared to their normal counterparts. The structural order of cells appears to be altered in transformed cells. This structural order is reflected in the altered morphology and motility observed in transformed cells compared to their normal counterparts, however, it is unclear whether the structural changes observed in cancer cells have any functional significance. We report here on the nature of the physical connections between the nucleus and cell periphery in nontransformed cells and demonstrate that the nucleus is dynamically coupled to the cell periphery via actin microfilaments. We also demonstrate that the dynamic coupling of the nucleus to the cell periphery via actin microfilaments is altered in Kirstenk-ras transformed rat kidney epithelial cells. This loss of structure-function relationship may be an important factor in the process of cell transformation.
Abscisic acid rescues the root meristem defects of the Medicago truncatula latd mutant

The LATD gene of the model legume, Medicago truncatula, is required for the normal function of three meristems, i.e. the primary root, lateral roots and nitrogen-fixing nodules. In latd mutants, primary root growth eventually arrests, resulting in a disorganized root tip lacking a presumptive meristem and root cap columella cells. Lateral root organs are more severely affected; latd lateral roots and nodules arrest immediately after emerging from the primary root, and reveal a lack of organization. Here we show that the plant hormone, abscisic acid (ABA), can rescue the latd root, but not nodule, meristem defects. Growth on ABA is sufficient to restore formation of small, cytoplasm-rich cells in the presumptive meristem region, rescue meristem organization and root growth and formation of root cap columella cells. In contrast, inhibition of ethylene synthesis or signaling fails to restore latd primary root growth. We find that latd mutants have normal levels of ABA, but exhibit reduced sensitivity to the hormone in two other ABA-dependent processes: seed germination and stomatal closure. Together, these observations demonstrate that the latd mutant is defective in the ABA response and indicate a role for LATD-dependent ABA signaling in M. truncatula root meristem function.
Oxygen nonstoichiometry and defect chemistry of the mixed conductor La0.9Ca0.1FeO3 − δ at low oxygen partial pressure

Abstract The equilibrium oxygen nonstoichiometry, δ, for the mixed ionic and electronic conducting perovskite La 0.9 Ca 0.1 FeO 3 − δ (LCF91) was measured for oxygen partial pressures, p O2 , between 10 − 3 and 10 − 21 atm and temperatures of 750 to 900 °C using a tubular, two-probe Pt|YSZ|LCF coulometric titration cell. XRD experiments confirmed that LCF91 remains a single phase perovskite under the reducing conditions of a fuel electrode, and reveal no evidence of reaction with the zirconia electrolyte. The p O2 -nonstoichiometry relationship can be interpreted using a dilute-solution point-defect model involving oxygen vacancies, electrons, and electron holes.
The morphology of tellurium-induced hydrocephalus.

Abstract Elemental tellurium added to the diet of gestating rats may result in hydrocephalus in the offspring. The hydrocephalus is communicating (non-obstructive) in type for the first few days, after which obstructions appear, such as closure of the subarachnoid space, and closure of the cerebral aqueduct. Most of the animals die by the end of the second week. A small number of animals survive because a spontaneous ventriculostomy appears in the occipital lobe toward the end of the first week, providing a shunt for the ventricular CSF into the subarachnoid space. During the first days after life when the hydrocephalus is communicating in type the pathology is mainly in the ependyma and subependyma. During the later stages of the disease when there is an obstructive hydrocephalus, the ventricular ependyma is destroyed, the white matter is edematous, the cerebral cortex is gradually destroyed, and connective tissue is present over the ependymal surface.
Remote sensing of protein adsorption using a single optical fiber

Abstract Fluorescence from dye-labeled protein adsorbed at a solid-liquid interface was monitored with a remote interfacial chemical sensor utilizing a single optical fiber. Evanescently excited and collected fluorescence obtained using the sensor showed that adsorption of protein onto the fiber core sensing surface from a flowing solution was detected. The results demonstrate that protein adsorption can be remotely detected and monitored with time. It is anticipated that this approach will be extended to the sensing of specific surface adsorbed molecules.
A generalization of the Gauss hypergeometric series

A generalization of the Gauss hypergeometric function to t variables is given, and the Euler identity is shown to hold for this generalized function. The corresponding generalization of the Saalschutz theorem is also obtained.
Carbonucleotoids and carbopeptoids: New carbohydrate oligomers

Abstract Carbonucleotoids (phosphate-bond linked carbohydrates) and carbopeptoids (peptidebond linked carbohydrates) are proposed as new oligosaccharide ligands. The ready access to these analogues is demonstrated by the facile synthesis of the tetrameric carbonucleotoid 1 .
The ideal of Standards and the reality of schools : Needed research

Abstract: Research potentially can assist in the process of implementing the National Science Education Standards. Existing research shows that changes called for in the Standards are difficult to put into practice, create dilemmas for teachers, require significant changes in teachers' values and beliefs, are fostered when change is pursued within departments within schools, are influenced powerfully by teacher collaboration in the work context, are often resisted strongly by parents, and often demand new student roles and different student work. The results of research on reform do not give a definitive picture of the most productive roles for students, the nature of the desired student work, how teachers can best be engaged in reassessing values and beliefs and taking responsibility for acquiring new professional competencies, how to realize “science for all,” and the most effective ways of involving parents. Research is needed which will: (1) be approached from multiple perspectives, (2) be conducted in the “real world,” (3) focus on interventions into conventional school practice, (4) not assume change can be driven from the top down, (5) be interpretive in nature, (6) focus on student roles and student work, (7) give major attention to teacher learning, (8) attend to parents' concerns, and (9) be approached systemically. © 2000 John Wiley & Sons, Inc. J Res Sci Teach 38: 3–16, 2001
The inhibitory effects of theophylline feeding on gluconeogenic enzymes in rat liver.

Abstract Diets containing 0.25% theophylline were fed to rats in one daily meal or ad libitum . The rats grew normally and did not exhibit symptoms characteristic of theophylline toxicity. Theophylline feeding decreased the hepatic pyruvate carboxylase (PC) (EC 6.4.1.1), phosphoenolpyruvate carboxykinase (PEPck) (EC 4.1.1.32) and fructose 1,6-diphosphatase (FDPase) (EC 3.1.3.11) activities in both the meal fed and ad libitum fed animals. The activity of glucose-6-phosphatase (G6Pase) (EC 3.1.3.9) decreased in the meal-fed but increased in the ad libitum fed rat. Similarly, when expressed as per unit of body weight, the relative activities remain the same indicating that a true adaptation occurred. The findings suggest that chronic theophylline ingestion may inhibit gluconeogenesis by decreasing the activities of these regulatory enzymes.
Amorphous film formation by ion mixing in binary metal systems

Abstract A structural difference rule is formulated according to which an amorphous binary alloy film is formed by ion mixing of multilayered sample when the two constituent metals are of different structure, apparently independently of their atomic sizes and electronegativities. The rule is supported by the experimental results we have obtained on eight selected binary metal systems, which cover all possible combinations between b.c.c., f.c.c. and h.c.p. structures. The previous data reported in the literature also support this rule. The available experimental data indicate that the validity of the rule may extend to other structures and to production techniques other than ion mixing. The amorphization mechanism is discussed in terms of the competition between two different structures resulting in frustration of the crystallization process.
Crystallization kinetics and the JMAK equation

Abstract In the present work the application of the Johnson-Mehl-Avrami-Kolmogorov (JMAK) theory for the calculation of the volume fraction crystallized is discussed for several particular cases of isothermal transformations. In particular, the following three situations, for which the JMAK theory requires extensions, are considered: (1) finite size effects and non-uniform nucleation, (2) anisotropic particle formation, and (3) transient nucleation. We present new equations which describe these three situations. In general, we find that anisotropic particle formation, finite size effects and non-uniform nucleation lead to a reduction of the crystallization rate. Furthermore, transformations which produce anisotropic particles are characterized by reduced values of the Avrami exponents. Finally, we demonstrate that corrections to the JMAK t4 law arising from time dependent nucleation must include size-dependent growth effects to obtain a logically consistent result.
Study of the fracture process using laser holographic interferometry and image analysis

The fracture process on cement based materials was studied using various holographic interferometry methods. Several aspects of the fracture process were studied on plane mortar (cement water and sand) and polypropylene fiber reinforced cement under different loading configurations. Sandwich holography was used to analyze mortar specimens loaded in tension. The real time method was used to determine the load increments required for accurate and easy evaluation of displacements. A single sensitivity vector setup was used for the evaluation of crack opening displacements and a multiple sensitivity vector set-up was used for the evaluation of full displacement fields. In both cases the holographic images were acquired by a digital image analysis system. First the images were enhanced for better recognition of the fringe patterns by elimination of high frequency noise and contrast improvement. Then the image analysis system was used for automatic fringe count. Sandwich holographic interferometry was also used to map the crack surfaces of the mortar specimens tested. The use of image analysis was essential for the evaluation of the interferograms. The image analysis system allowed for the direct application of a moire pattern method resulting in topographic contour maps. Crack pattern characterization on polypropylene fiber reinforced specimens was made using the ''piggy back'' method to record double exposure reflection holograms. Image processing was used for image enhancement and automatic computation of crack spacings. 1.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Enhanced survival of apparent presynaptic elements on polylysine-coated beads by inhibition of non-neuronal cell proliferation.

Abstract Increased survival of presynaptic-like neuronal profiles was found in cell cultures of rat cerebellum when the non-neuronal cell numbers were reduced with an antimitotic drug. In both treated and untreated cell cultures, neurites grew onto the polylysine-coated surface of sepharose beads and formed a swelling. The neuronal swelling contained an accumulation of synaptic vesicles and a membrane density at the site of contact with the bead and was called an apparent presynaptic element. The apparent presynaptic elements in untreated cultures increased in number from the time the beads were added to the culture to 7 days incubation and then showed a decrease to one half the 7-day value at 14 days incubation. A 75% reduction in cell division of non-neuronal cells was seen in cultures exposed to a 5 × 10 −6 M cytosine arabinoside (Ara-C) for 2 days. Adding polylysine-coated beads to cultures treated with Ara-C showed at 14 days incubation a 7-fold increase in the number of apparent presynaptic elements as compared to untreated cultures. Additional experiments examined the numbers of neurites on the beads and found only small differences between treated and untreated cultures. A decrease, however, was shown in the number of glial fibrillary acidic protein staining astrocytes on the surface of the beads in treated cultures. The reduction of astrocytes by Ara-C appeared to enhance the survival of apparent presynaptic elements but did not enhance the growth of neurites. These results suggest that proliferating non-neuronal cells at a site of injury in the central nervous system may inhibit the formation of synaptic contacts and the growth of neurites through the site of injury.
Beginning Teachers: Sink or Swim?

Varah, Theune, and Parker provide a brief review of the literature on begin ning teachers and document the need for induction programs. The authors also describe the University of Wiscon sin-Whitewater Teacher Induction Pro gram and describe how induction teams, consisting of mentor teachers, school administrators, and university personnel, identify areas of accomplish ment, concern, and improvement for be ginning teachers. Finally, data are pre sented from a small scale experimental study that suggest that the induction program is achieving its primary objec tive of enhancing teacher growth.
An approximation algorithm for the edge-dilation k-center problem

We provide an approximation algorithm for selecting centers in a complete graph so as to minimize the maximum ratio of the distance between any two nodes via their respective centers to their true graph distance. Placing centers under such an objective function is important in designing efficient communication networks which rely on hubs for routing.
Ethics gap in surgery.

Abstract Background . Discussion of ethical issues occurs much less often in the surgical than in the medical literature. The reasons for this "ethics gap" are unknown. Methods . Our clinical faculty ranked the ethical and legal acceptability of four treatment options in two cases of surrogate decision making. Only one option in each case was ethically and legally unacceptable (treating despite objection by the surrogate decision maker). Results . Surprisingly often, faculty mistakenly believed the ethically unacceptable option to be acceptable, and the legally unacceptable option to be acceptable. Surgeons were not ethically different from other physicians. Surgeons (19 of 31, 62%), however, were significantly ( p Conclusions . This pilot study did not identify why the surgical literature contains a relative dearth of ethics discussion. Broader investigations are needed, because it is important that we understand the reasons for the gap. Surgeons' strong ethic of personal responsibility for patients' welfare should be transmitted to young trainees, a goal best achieved by discussing and writing about ethics. Moreover, our legal data suggest that a gap may also exist between surgeons and other physicians in understanding health law.
Transport Aircraft System Identification from Wind Tunnel Data

Recent studies have been undertaken to investigate and develop aerodynamic models that predict aircraft response in nonlinear unsteady flight regimes for transport configurations. The models retain conventional static and rotary dynamic terms but replace conventional acceleration terms with more general indicial functions. In the Integrated Resilient Aircraft Controls project of the NASA Aviation Safety Program one aspect of the research is to apply these current developments to transport configurations to facilitate development of advanced controls technology. This paper describes initial application of a more general modeling methodology to the NASA Langley Generic Transport Model, a sub-scale flight test vehicle.
Quorum sensing in bacterial species that use degenerate autoinducers can be tuned by using structurally identical non-native ligands

Many bacteria use quorum sensing (QS) to regulate cell-density dependent phenotypes that play critical roles in the maintenance of their associations with eukaryotic hosts. In Gram-negative bacteria, QS is primarily controlled by N-acylated L-homoserine lactone (AHL) signals and their cognate LuxR-type receptors. AHL-LuxR-type receptor binding regulates the expression of target genes necessary for QS phenotypes. We recently identified a series of non-native AHLs capable of intercepting AHL-LuxR binding in the marine symbiont Vibrio fischeri, and thereby strongly promoting or inhibiting QS in this organism. V. fischeri utilizes N-(3-oxo)-hexanoyl L-HL (OHHL) as its primary QS signal, and OHHL is also used by several other bacterial species for QS. Such signal degeneracy is common among bacteria, and we sought to determine if our non-native LuxR agonists and antagonists, which are active in V. fischeri, would also modulate QS phenotypes in other bacteria that use OHHL. Herein, we report investigations into the activity of a set of synthetic LuxR modulators in the plant pathogen Pectobacterium carotovora subsp. carotovora Ecc71. This pathogen uses OHHL and two closely related LuxR-type receptors, ExpR1 and ExpR2, to control virulence, and we evaluated their responses to synthetic ligands by quantifying virulence factor production. Our results suggest an overall conservation in the activity trends of the ligands between the ExpR receptors in P. carotovora Ecc71 and LuxR in V. fischeri, and indicate that these compounds could be used as tools to study QS in an expanded set of bacteria. Notable differences in activity were apparent for certain compounds, however, and suggest that it might be possible to selectively regulate QS in bacteria that utilize degenerate AHLs.
Rapid, quantitative isolation of mitochondria from rat liver using Ficoll gradients in vertical rotors

A method for the rapid, quantitative isolation of rat liver mitochondria has been developed. The method consists of placing portions of whole liver homogenate on linear Ficoll gradients followed by reorienting rate-zonal centrifugation in a vertical rotor. Fractions collected from the gradient were analyzed for protein, cytochrome oxidase, and a number of marker enzymes to determine mitochondrial location and the extent of their contamination with other cellular organelles. In the fraction designated as the mitochondrial peak, 85% of the total cytochrome oxidase activity was recovered. Contamination with other cellular organelles ranged from 7.07 to 14.05%. The respiratory control ratio of the isolated mitochondria was 8.10, indicating they were well coupled.
Histopathologic and bacterial evaluation of conventional and new copper amalgams

In vivo pulpal responses in monkeys and in vitro bacterial inhibition studies were completed on new copper amalgams, Sybraloy, ® Dispersalloy, ® Tytin® and a conventional Spheraloy® amalgam. Amalgams were placed in cavities lined with ZOE and in unlined cavities. Silicate and ZOE were used as controls. A total of 165 adult monkey teeth were evaluated at 3 days, 5 and 8 weeks. At 3 days the pulpal responses elicited by the copper amalgams appeared similar to conventional Spheraloy, ® all showing a slight to moderate response. At 5 weeks the majority of amalgams exhibited a slight pulpal response with a tubular reparative dentin under each restoration. The 8 week pulpal response showed a reduction of the inflammatory response characterized by a tubular reparative dentin with a uniform zone of predentin. Lined ZOE controls exhibited a slight response while silicate showed a moderate response with some persistent chronic inflammation. In vitro bacterial tests revealed that the various amalgams had little to no inhibitory effect on the three serotypes of S. mutans that are most prominent in humans.
Predation and predatory play behaviour of domestic cats

Abstract This study investigated the factors controlling behavioural responses of the domestic cat to its prey. Experiment 1 identified three temporally-associated groups of behaviours, and associated these differentialy with killing. Cat behaviours were independent of prey activity. Hunger was not a necessary condition for killing. In experiment 2, I manipulated hunger and the size of the prey. I found that: (1) The probability of a kill increased directly with hunger. (2) When the prey was large or difficult, the probability of a kill decreased. (3) The probability of killing was predictable if the levels of the factors hunger and prey size were known. (4) When these factors were in conflict, cats tended to play with the prey before, after, or instead of, killing. The relevance of these results to other studies of the control of predatory and playful behaviours is discussed.
Potentiation of postjunctional cholinergic sensitivity of rat diaphragm muscle by high-energy-phosphate adenine nucleotides

The cholinergic sensitivity of rat diaphragm muscle, me-sured as the magnitude of depolarization responses to repetitive, iontophoretic pulses of acetylcholine (ACh) onto neuromuscular endplates, is increased by addition of ATP to the perfusion medium. Depolarization responses begin to increase within the first min after addition of 10 mM ATP and plateau at 60% above control levels (mean value) after 4 to 6 min. Neither the magnitude nor the time course of the potentiations corresponds to changes in resting potential or membrane resistance. Other nucleotides are equally or less effective at the same concentration: ATP=ADP greater than UTP greater than AMP=GTP (=no added nucleotide control) The duration of the individual ACh responses does not increase during continuous exposure to the active nucleotides for up to 15 min except when the muscle is pretreated with eserine. Mild enzymatic predigestion of the muscle with collagenase and then protease, increasing the availability of the postjunctional membrane to bath-applied drugs, decreases the variability and increases the magnitude of the potentiation to a given dose of ATP. The dose-response curve for ATP is then more than half-maximal at 1 mM and the ranking of the other nucleotides relative to ATP is the same as without predigestion. There is an optimum Ca++ concentration for the potentiation between zero and 2 mM: potentiation is enhanced in Ca++ -free medium, partially blocked in twice-normal Ca++ medium, and totally blocked in Ca++ -free medium 10 min after a 5 min exposure to 2.5 mM EGTA. The similar Ca++ dependence of ACh receptor activation in the absence of added nucleotide suggests that ATP directly facilitates receptor activation by ACh. This facilitory action could be one of the physiological roles for the ATP released from stimulated phrenic nerve.
Exploring features of integrative teaching through a microanalysis of connection-making processes in a health sciences curriculum

The interconnected nature of knowledge in the health sciences is not always reflected in how curricula, courses, and learning activities are designed. Thus have scholars advocated for more explicit attention to connection-making, or integration, in teaching and learning. However, conceptual and empirical work to guide such efforts is limited. This study analyzed classroom processes to determine what connections educators promoted in their classrooms and how those connections were made. A qualitative, focused ethnography design explored connection-making in a health science curriculum. Eight instructors were observed during ten class sessions resulting in 35 h of video data. Video data were entered into the observational software, Noldus Observer, and coded using continuous sampling. Frequency and duration of connections made were calculated in Noldus. Connection-making involved four interactive elements: The topic under direct consideration, other domains of professional knowledge (practice, student experience, research, theory, other content, core construct of the profession, external influences, metacognition), the integrative processes instructors used to connect a topic to other knowledge domains (informal example, stories, questioning, linking statements, formal cases, and program descriptions), and the learning and instructor context (type and purpose of course, instructor personal and professional experience). These elements are presented as an initial integrative learning taxonomy that can be used to guide explicit attention to connection-making in education and research.
Effect of postdrawing on the permeability of gases in blown polyethylene film

The effect of orientation on the structure and transport properties of high-density polyethylene film has been studied. Microstructure was characterized using small-angle light scattering, birefringence, and wide-angle x-ray scattering. Water vapor and oxygen transmission rates were determined as a function of film draw ratio. The object of the present work is to correlate the effects of postprocessing conditions on the transport properties and morphology of linear polyethylene. High-density spherulitic polyethylene films were produced by blown film extrusion and subsequently oriented by longitudinal stretching in a postoperation. Various degrees of orientation were imparted to the films, with percent crystallinity, sample orientation and transport properties measured as a function of draw ratio. For the postoriented films, results indicate there was no significant change in percent crystallinity with increasing draw ratio although water vapor and oxygen permeability decreased substantially. This is attributed to the increased orientation of the crystalline and amorphous regions and rod-like and microfibril structure formation brought about by the drawing process. Lower processing temperatures result in increased orientation which improves the vapor barrier properties.
Adverse prognostic significance of infraclavicular lymph nodes detected by ultrasonography in patients with locally advanced breast cancer

Abstract Background: Ultrasonography is increasingly used to evaluate the nodal status of breast cancer patients and specialized positioning permits assessment of the infraclavicular fossa. However, the incidence and significance of infraclavicular (level III) adenopathy detected sonographically in locally advanced breast cancer (LABC) has not been defined. Methods: The study population consisted of 146 LABC patients registered in a prospective trial of induction chemotherapy between 1991 and 1996. All patients underwent ultrasound imaging before and after chemotherapy. Median follow-up was 32 months. Results: Forty-two of 146 patients (29%) had suspicious infraclavicular adenopathy; all 42 had additional positive axillary lymph nodes by ultrasound. Disease-free and overall survival for the patients with suspicious infraclavicular adenopathy was significantly worse compared with patients without this feature; disease-free survival 50% versus 68% ( P = 0.112); overall survival 58% versus 83% ( P = 0.026). Conclusions: Nearly one third of LABC patients will have infraclavicular lymph node involvement by ultrasound imaging; this finding is a significant adverse prognostic feature, and we recommend that infraclavicular nodal evaluation become a routine component of the sonographic workup of breast cancer patients, particularly if lower axillary lymph nodes appear involved.
Learning innovation at scale

The rapid developments in online education raise new issues for the future of learning and universities, practical questions about what counts as good design, and new opportunities for research. This workshop brings together practitioners, learning platform innovators, and researchers who draw on a multi-disciplinary range of theory and methodology. We will share insights about the current state and next directions for research and practice in online learning and technology.
Behavior of embryonic chick heart cells in culture. 3. Spatial distribution of epidermal growth factor in heart muscle cells.

Abstract Muscle cell-enriched primary cell cultures were prepared from 8-day embryonic chick heart ventricles. Immunostaining with an anti-EGF antibody detected the presence of EGF in the heart muscle cells, in a perinuclcar distribution. In addition, some of the EGF appeared to be associated with the sarcomercs. Moreover, immunostaining with an anti-EGF receptor antibody also detected perinuclear localization, albeit not among the sarcomeres. Previous studies have shown that the heart muscle and non-muscle cells in culture respond to EGF to increase [3H]thymidine incorporation and cell division (Lau, 1993b). These data suggest the roles of EGF as a natural regulator in the development of the embryonic chick heart
Automatic imitation of biomechanically possible and impossible actions: effects of priming movements versus goals

Recent behavioral, neuroimaging, and neurophysiological research suggests a common representational code mediating the observation and execution of actions; yet, the nature of this representational code is not well understood. The authors address this question by investigating (a) whether this observation-execution matching system (or mirror system) codes both the constituent movements of an action as well as its goal and (b) how such sensitivity is influenced by top-down effects of instructions. The authors tested the automatic imitation of observed finger actions while manipulating whether the movements were biomechanically possible or impossible, but holding the goal constant. When no mention was made of this difference (Experiment 1), comparable automatic imitation was elicited from possible and impossible actions, suggesting that the actions had been coded at the level of the goal. When attention was drawn to this difference (Experiment 2), however, only possible movements elicited automatic imitation. This sensitivity was specific to imitation, not affecting spatial stimulus-response compatibility (Experiment 3). These results suggest that automatic imitation is modulated by top-down influences, coding actions in terms of both movements and goals depending on the focus of attention.
Synexin-mediated fusion of bovine chromaffin granule ghosts. Effect of pH.

Abstract Synexin induces chromaffin granule ghosts to fuse one to another, a process which is followed continuously and quantitatively by monitoring the mixing of the intragranular aqueous compartments. A freeze-thaw technique was used for preparing chromaffin granule ghosts loaded with a self-quenching concentration of the fluorescent, high molecular weight probe FITC-Dextran. When the loaded ghosts were mixed with empty ghosts in the presence of synexin, the two compartments fused, resulting in the dilution of the probe with the concomitant increase in fluorescence. So as to suppress possible leakage signals, anti-fluorescein antibodies which quench probe fluorescence were present in the reaction media. Synexin-mediated fusion of freeze-thaw (F/Th) ghosts and binding of 125 I-synexin to these membranes were found to be dependent on Ca 2+ concentration, but only in a partial manner. However, these two synexin-mediated properties were demonstrably sensitive to [H + ] in the medium. A detailed pH profile of fusion revealed an apparent midpoint of activation at approx. pH 5.2, with asymptotic value at pH 4 (maximum) and pH 7.2 (minimum). In our attempt to determine whether the pH effect was on the synexin or on the membranes, we found that fusion was blocked only by treatment of the membranes with the membrane-impermeant carboxyl group modifier 1-ethyl-3(4-azonia-4,4-dimethylpentyl)carbodiimide. These data suggest that membrane fusion evoked by synexin seems to be promoted by rendering the F/Th membranes relatively less negatively charged while the synexin becomes more positively charged. The fusion process was entirely dependent upon synexin concentration; the k 1/2 under optimal conditions of p C a and pH was 85 nM. Similar to what has been previously found with intact granules, an anti-synexin polyclonal antibody partially (48%) blocked fusion, as did pretreatment of the chromaffin granules ghosts with trypsin (30%). We conclude that the coincident p Ca and pH sensitivity of synexin-mediated binding to chromaffin granule membranes and their subsequent fusion might be associated with physiological changes in the concentration of both cations in the cytoplasm of secreting chromaffin cells.
Bridging the divide: comments on the Restructured Clinical Scales of the MMPI-2.

In this comment, I discuss the target articles written by Nichols (2006/this issue) and Rogers, Sewell, Harrison, and Jordan (2006/this issue) regarding the Restructured Clinical (RC) Scales (Tellegen et al., 2003) of the MMPI–2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989). Both articles provide thoughtful discussion of the extent to which the RC Scales achieved the primary goals set forth by Tellegen et al., but they set different tones and come to somewhat different conclusions. I argue that the initial studies conducted on the RC Scales suggest a promising future for them. However, further studies are needed to explore the construct validity of the scales, assess their incremental validity with respect to other more established MMPI–2 scale sets, and determine their interpretive meaning in clinical contexts.
Minimization of $\ell_{1-2}$ for Compressed Sensing

We study minimization of the difference of $\ell_1$ and $\ell_2$ norms as a nonconvex and Lipschitz continuous metric for solving constrained and unconstrained compressed sensing problems. We establish exact (stable) sparse recovery results under a restricted isometry property (RIP) condition for the constrained problem, and a full-rank theorem of the sensing matrix restricted to the support of the sparse solution. We present an iterative method for $\ell_{1-2}$ minimization based on the difference of convex functions algorithm and prove that it converges to a stationary point satisfying the first-order optimality condition. We propose a sparsity oriented simulated annealing procedure with non-Gaussian random perturbation and prove the almost sure convergence of the combined algorithm (DCASA) to a global minimum. Computation examples on success rates of sparse solution recovery show that if the sensing matrix is ill-conditioned (non RIP satisfying), then our method is better than existing nonconvex compre...
Structural relaxation in liquids and glasses by transient hole burning

Ultrafast transient and permanent hole burning and fluorescence line narrowing are used to study the dynamic interaction between the electronic states of a nonpolar solute (dimethyl-s-tetrazine) and its solvent (glycerol) from low temperature glass to room temperature liquid. A model for phonon-modulated interactions not only describes the glass phase results, but also extrapolates to describe the short time dynamics in the liquid phase. However, this mechanism does not account for all of the ultrafast interaction seen at room temperature. A second mechanism connected to the structural coordinates of the liquid is identified. It has a strongly temperature dependent relaxation rate, which becomes subpicosecond at room temperature. This mechanism's rate is significantly faster than rates measured by other structural relaxation experiments.
Identification and characterization of a rhizosphere β-galactosidase from Pisum sativum L.

Plant enzyme activities in the rhizosphere potentially are a resource for improved plant nutrition, soil fertility, bioremediation, and disease resistance. Here we report that a border cell specific β-galactosidase is secreted into the acidic extracellular environment surrounding root tips of pea, as well as bean, alfalfa, barrel medic, sorghum, and maize. No enzyme activity was detected in radish and Arabidopsis, species that do not produce viable border cells. The secreted enzyme activity was inhibited by galactose and 2-phenylethyl 1-thio-β-d-galactopyranoside (PETG) at concentrations that altered root growth without causing cell death. A tomato galactanase encoding gene was used as a probe to isolate a full length pea cDNA clone (BRDgal1) from a root cap-border cell cDNA library. Southern blot analysis using full length BRDgal1 as a probe revealed 1–2 related sequences within the pea genome. BRDgal1 mRNA expression was analysed by whole mount in situ hybridization (WISH) and found to occur in the outermost peripheral layer of the cap and in suspensions of detached border cells. No expression was detected within the body of the root cap. Repeated efforts to develop viable hairy root clones expressing BRDgal1 antisense mRNA under the control of the CaMV35S promoter, whose expression in the root cap is limited to cells at the root cap periphery only during root emergence, were unsuccessful. These data suggest that altered expression of this enzyme is deleterious to early root development.
Mandibular path in the grinding phase of mastication--a review.

T h e path of the human mandible has been studied during both normal mastication and artificial movement. This review Will focus largely on investigations of normal chewing, and studies of the border movements such as those of Posselt ~ will not be considered. The tooth-guided glide in the grinding phase of the chewing cycle will be reviewed in some detail, and studies in which jaw position and muscle activity have been simultaneously recorded will be discussed.
A calorimetric study of liquid silver and liquid tin

Abstract An adiabatically shielded drop calorimeter has been used to measure the enthalpies of liquid silver (1243 to 1588 K) and liquid tin (1222 to 1745 K). The results for silver are expressed as H o (T) − H o (298.15 K) = “−1102.6 + 8,111T)’ cal mol −1 and those for tin, as H o (T) − H o (298.15 K) = “−428.9 + 6.900(T/ K )’ cal mol −1 . With a literature value for the enthalpy of solid silver at the melting point, the enthalpy of fusion of silver becomes 2590 cal mol −1 .