cssi/SciSciGPT-SciSciNet huggingface dataset:
Silicon isotopic fractionation of CAI-like vacuum evaporation residues

Calcium-, aluminum-rich inclusions (CAIs) are often enriched in the heavy isotopes of magnesium and silicon relative to bulk solar system materials. It is likely that these isotopic enrichments resulted from evaporative mass loss of magnesium and silicon from early solar system condensates while they were molten during one or more high-temperature reheating events. Quantitative interpretation of these enrichments requires laboratory determinations of the evaporation kinetics and associated isotopic fractionation effects for these elements. The experimental data for the kinetics of evaporation of magnesium and silicon and the evaporative isotopic fractionation of magnesium is reasonably complete for Type B CAI liquids (Richter F. M., Davis A. M., Ebel D. S., and Hashimoto A. (2002) Elemental and isotopic fractionation of Type B CAIs: experiments, theoretical considerations, and constraints on their thermal evolution. Geochim. Cosmochim. Acta66, 521–540; Richter F. M., Janney P. E., Mendybaev R. A., Davis A. M., and Wadhwa M. (2007a) Elemental and isotopic fractionation of Type B CAI-like liquids by evaporation. Geochim. Cosmochim. Acta71, 5544–5564.). However, the isotopic fractionation factor for silicon evaporating from such liquids has not been as extensively studied. Here we report new ion microprobe silicon isotopic measurements of residual glass from partial evaporation of Type B CAI liquids into vacuum. The silicon isotopic fractionation is reported as a kinetic fractionation factor, αSi, corresponding to the ratio of the silicon isotopic composition of the evaporation flux to that of the residual silicate liquid. For CAI-like melts, we find that αSi = 0.98985 ± 0.00044 (2σ) for 29Si/28Si with no resolvable variation with temperature over the temperature range of the experiments, 1600–1900 °C. This value is different from what has been reported for evaporation of liquid Mg2SiO4 (Davis A. M., Hashimoto A., Clayton R. N., and Mayeda T. K. (1990) Isotope mass fractionation during evaporation of Mg2SiO4. Nature347, 655–658.) and of a melt with CI chondritic proportions of the major elements (Wang J., Davis A. M., Clayton R. N., Mayeda T. K., and Hashimoto A. (2001) Chemical and isotopic fractionation during the evaporation of the FeO–MgO–SiO2–CaO–Al2O3–TiO2–REE melt system. Geochim. Cosmochim. Acta65, 479–494.). There appears to be some compositional control on αSi, whereas no compositional effects have been reported for αMg. We use the values of αSi and αMg, to calculate the chemical compositions of the unevaporated precursors of a number of isotopically fractionated CAIs from CV chondrites whose chemical compositions and magnesium and silicon isotopic compositions have been previously measured.
Interaction between Preservice Teachers and School Social Work Interns in an Urban School Setting

This study examined the results of a year of collaboration and interactions between preservice teachers and social work interns in joint seminars and field-based activities in four urban elementary schools. The program purposely structured formal and informal opportunities for meaningful partnerships between preservice teachers and social work interns to solve problems and challenges unique to urban schools. The findings revealed that overall, students found the collaboration to be a positive experience that provided a larger support system for addressing their needs.
Selective pulmonary vasodilation by low-dose infusion of adenosine triphosphate in newborn lambs

The systemic and pulmonary vascular effects of adenosine 5′-triphosphate (ATP) were investigated in 12 newborn lambs during normoxia and during alveolar hypoxia (10% oxygen, 5% carbon dioxide, and 85% nitrogen). Lambs had catheters in the descending aorta, main pulmonary artery, and right and left atria, and a flow transducer around the main pulmonary artery, and were studied after a 3-day recovery. We infused ATP or an equal volume of saline solution (control) into the right atrial line in doses ranging from 0.01 to 2.5 μmol/kg per minute. In normoxic lambs, ATP caused a significant decrease in pulmonary vascular resistance in doses of 0.08 to 2.5 μmol/kg per minute, and in systemic vascular resistance in doses of 0.3 to 2.5 μmol/kg per minute. Infusion of ATP in hypoxic lambs caused decreases in pulmonary artery pressure and pulmonary vascular resistance in all the doses tested. Systemic vascular resistance decreased, and cardiac output and heart rate increased in doses greater than 0.3 μmol/kg per minute in hypoxic lambs during ATP infusion. The effects of ATP in hypoxic lambs were not blocked by propranolol, indomethacin, or theophylline. Plasma ATP levels in left atrial blood samples did not change significantly during the infusion of ATP. We conclude that ATP is a vasodilator in lambs, and its effects are specific for pulmonary circulation at doses of ≤0.15 μmol/kg per minute. The vasodilator effects of ATP appear to be independent of P 1 purinergic and β-adrenergic mechanisms, and of prostacyclin synthesis.
Survival in Infarct Related Intramyocardial Dissection: Importance of Early Echocardiography and Prompt Surgery

Abstract Infarct related intramyocardial dissection, an unusual mechanical complication associated with recent inferior/inferoposterior myocardial infarction, is characterized by a septal defect and a dissection tract that originates on the left side of the interventricular septum, extends beyond the septum into the right ventricular free wall, and subsequently re-enters the right ventricle. The utility of echocardiography for diagnosis has been described. Despite aggressive therapy, the prognosis of intramyocardial dissection is reported to be dismal. We describe the use of prompt echocardiography in two patients, which established the diagnosis of infarct related intramyocardial dissection allowing early definitive surgery and long-term survival.
Effect of cross-linking on the chaperone-like function of alpha crystallin.

Abstract Alpha crystallin can function as a molecular chaperone in suppressing the heat-induced aggregation of other crystallins and proteins. During cataractogenesis, α-crystallin becomes a water-insoluble, high-molecular-weight, cross-linked aggregate. To determine whether the chaperone activity of alpha crystallin is lost during this age-related modification, extracts were prepared by sonication of water-insoluble proteins isolated from aged bovine lenses and human cataract lenses. All the preparations were tested for chaperone-like activity using βL-crystallin as the target protein and the percentage of α-crystallin in water-insoluble sonicated supernatant (WISS) was determined by slot blot immunoassay. The WISS from bovine as well as human lenses were still effective in protecting βL-crystallin aggregation at 56°C. The bovine cortical WISS with 50% immunoreactive α-crystallin showed 62% of the chaperone-like activity displayed by native α-crystallin. The WISS from bovine lens nucleus and human lenses with 17% and 5% immunoreactive α-crystallin showed 19% and 4% chaperone-like activity compared to native α-crystallin. Prior treatment of the WISS of both bovine and human lenses with dithiothreitol resulted in nearly 50% increase in chaperone-like activity suggesting possible loss of chaperone-like activity due to disulfide cross-links. To see if the chaperone-like activity of α-crystallin can be altered by non-disulfide cross-linking, native α-crystallin isolated from bovine lenses was cross-linked with dimethylsuberimidate (DMS) and dimethyl 3,3′-dithiobispropionimidate (DTBP) and tested for chaperone-like activity. The DMS cross-linked α-crystallin was effective in inhibiting the aggregation of βL-crystallins at 56°C, but required a two- to five-fold higher concentration than the native α-crystallin. α-Crystallin with higher degree of cross-linking showed lower chaperone-like activity. α-Crystallin cross-linked with DTBP, a cleavable cross-linking agent, also showed a 80% loss in chaperone-like activity. However, when the DTBP cross-linked α-crystallin was treated with dithiothreitol to cleave the cross-links there was a 50% recovery in the chaperone-like activity. These data suggest that the age-related cross-linking, which restricts the molecular flexibility of α-crystallin decreases its chaperone-like function.
Human head-neck biomechanics under axial tension

A significant majority of cervical spine biomechanics studies has applied the external loading in the form of compressive force vectors. In contrast, there is a paucity of data on the tensile loading of the neck structure. These data are important as the human neck not only resists compression but also has to withstand distraction due to factors such as the anatomical characteristics and loading asymmetry. Furthermore, evidence exists implicating tensile stresses to be a mechanism of cervical spinal cord injury. Recent advancements in vehicular restraint systems such as air bags may induce tension to the neck in adverse circumstances. Consequently, this study was designed to develop experimental methodologies to determine the biomechanics of the human cervical spinal structures under distractive forces. A part-to-whole approach was used in the study. Four experimental models from 15 unembalmed human cadavers were used to demonstrate the feasibility of the methodology. Structures included isolated cervical spinal cords, intervertebral disc units, skull to T3 preparations, and intact unembalmed human cadavers. Axial tensile forces were applied, and the failure load and distraction were recorded. Stiffness and energy absorbing characteristics were computed. Maximum forces for the spinal cord specimens were the lowest (278 N +/- 90). The forces increased for the intervertebral disc (569 N +/- 54). skull to T3 (1555 N +/- 459), and intact human cadaver (3373 N +/- 464) preparations, indicating the load-carrying capacities when additional components are included to the experimental model. The experimental methodologies outlined in the present study provide a basis for further investigation into the mechanism of injury and the clinical applicability of biomechanical parameters.
Tracking Ships from Fast Moving Camera through Image Registration

This paper presents an algorithm that detects and tracks marine vessels in video taken by a nonstationary camera installed on an untethered buoy. The video is characterized by large inter-frame motion of the camera, cluttered background, and presence of compression artifacts. Our approach performs segmentation of ships in individual frames processed with a color-gradient filter. The threshold selection is based on the histogram of the search region. Tracking of ships in a sequence is enabled by registering the horizon images in one coordinate system and by using a multihypothesis framework. Registration step uses an area-based technique to correlate a processed strip of the image over the found horizon line. The results of evaluation of detection, localization, and tracking of the ships show significant increase in performance in comparison to the previously used technique.
Comparative reduction values of carbohydrates by Hagedorn-Jensen, Meyer-Benedict and Folin-Wu Methods.

Summary1. Our values except those for levulose agree with the data of previous investigators.2. Levulose has a higher reduction value than glucose.3. The difference in behavior of galactose and glucose toward Folin-Wu copper solution is not due to difference in velocity of reduction or differences in pH, but to structural differences in the two sugars.4. Glucose picric acid standards used in the Benedict-Lewis methods are stable for a period of at least two years.
Simultaneous dependence between firm-level stock returns

We show that use of ordinary least-squares to explore relationships involving firm-level stock returns as the dependent variable in the face of structured dependence between individual firms leads to an endogeneity problem. This in turn leads to biased and inconsistent least-squares estimates. A maximum likelihood estimation procedure that will produce consistent estimates in these situations is illustrated. This is done using methods that have been developed to deal with spatial dependence between regional data observations, which can be applied to situations involving firm-level observations that exhibit a structure of dependence. In addition, we show how to correctly interpret maximum likelihood parameter estimates from these models in the context of firm-level dependence, and provide a Monte Carlo as well as applied illustration of the magnitude of bias that can arise.
Depth of Fields: Travel Photography and Spatializing Modernities in Northern Pakistan

Western travelers move throughout the world—especially to places in ‘the East’—believing themselves to be harbingers of modernity, spreading capitalism, socioeconomic development, Western culture, and other promises of modernization to places they assume are existing in states of pristine Otherness. In this paper I look at interactions between travelers and locals that reveal differing spatial imaginaries of ‘modernity’, and at how these reflect and produce different narratives of who is modern and where modernity exists. By using ethnographic material, I examine discursive and material interactions surrounding modernity through the examples of travelers' practices of photography, dress, and knowledge of Muslim women's veiling. In this paper I look to a located, gendered, and particular expression of an Islamic modernity, one that embraces improvements in quality of life that modern technologies of health care, agricultural production, and sanitation may bring, and which simultaneously embraces nonsecular...
Disruption of dengue virus transmission by mosquitoes

Current control efforts for mosquito-borne arboviruses focus on mosquito control involving insecticide applications, which are becoming increasingly ineffective and unsustainable in urban areas. Mosquito population replacement is an alternative arbovirus control concept aiming at replacing virus-competent vector populations with laboratory-engineered incompetent vectors. A prerequisite for this strategy is the design of robust anti-pathogen effectors that can ultimately be genetically driven through a wild-type population. Several anti-pathogen effector concepts have been developed that target the RNA genomes of arboviruses such as dengue virus in a highly sequence-specific manner. Design principles are based on long inverted-repeat RNA triggered RNA interference, catalytic hammerhead ribozymes, and trans-splicing Group I Introns that are able to induce apoptosis in virus-infected cells following splicing with target viral RNA.
William Howard Taft: The Travails of a Progressive Conservative. By Jonathan Lurie. New York: Cambridge University Press, 2012. 214 pp.

William Howard Taft: The Travails of a Progressive Conservative. By Jonathan Lurie. New York: Cambridge University Press, 2012. 214 pp. William Howard Taft has not fared well with historians. Surveys of scholars uniformly have graded him "average" in comparative ratings with other presidents. Jonathan Lurie, a legal historian, thinks this poor standing is undeserved. He has reevaluated this mediocre reputation, arguing that Taft was a "progressive president" who "modernized the presidency." Lurie approaches this task primarily through biography, relying heavily on Taft's correspondence to track his career and thinking about people and politics. In the process, Lurie sought to explain Taft's self-characterization as a "progressive conservative." Taft followed in his father's footsteps by attending Yale and being admitted to the bar in Cincinnati, Ohio. The younger Taft advanced rapidly through the legal system, beginning as an assistant prosecutor in Cincinnati, continuing as a trial judge for the Ohio courts, and serving as solicitor general of the United States prior to presiding as a U.S. circuit court judge. In 1900, President William McKinley asked him to head the Philippine Commission, which guided the colonies' preparation for self-governance. A specialist in military legal history, Lurie devoted much of a chapter to Taft's contentious relationships with American field commanders then battling Filipino insurgents. President Theodore Roosevelt appointed Taft as secretary of war in 1904, which put these two friends in closer contact, a relationship that Lurie chronicles from the Taft and Roosevelt papers. Their warmth unraveled with the approach of the 1912 election, when Roosevelt sought to reclaim the Republican presidential nomination. Lurie's research in the Taft correspondence (some of which was from excerpted passages contained in the papers of Henry Pringle, Taft's early biographer) offers insights into the president's self-deprecating personality. Taft had no stomach for "politics," realized his ineptitude for it, and disavowed an ambition to be president, despite his decision to deny Roosevelt's return to the White House. A brief chapter and epilogue round out Lurie's review of Taft's postpresidential career, with the author noting that he plans a separate study of Taft's years as chief justice (1921-30). Despite soldiering on in a position that he never actively sought, Taft performed fairly well in the job as president, in Lurie's opinion. He brought a methodical mind and juristic sense of fairness to administration. He supported a number of policies that are considered "progressive," such as corporate and individual income taxes, an executive budget, the 1910 railroad regulation act, and postal savings. He initiated more antitrust suits than his predecessor Roosevelt. Lurie's statement that these actions "exceeded the record set by his predecessors" may be accurate (p. …
A note on the identifiability of parallel and serial processes.

Due to the significant research effort devoted to discovering whether certain psychological processes are serial or parallel, it seems important to establish the degree to which such processes are identifiable and to investigate possible ways in which such knowledge can improve our experiments. General definitions of parallel and serial systems are given, followed by a qualitative summary of identifiability results obtained with special classes of exponential systems. Some of these results are applied to a current experimental paradigm, and possible
SUBSTRUCTURAL STRENGTHENING OF A PRECIPITATION-HARDENED MOLYBDENUM ALLOY.

Abstract An experimental study on a precipitation hardened molybdenum alloy (Mo-0.48 Ti-0.11 Zr-0.02C) has shown that the strengthening effect of fine carbide particles is in very good agreement with predictions of the Orowan mechanism of hardening by nondeforming particles. Additional strengthening achieved by swaging and wire drawing this alloy is shown to be related directly to the fineness of the substructure developed by these operations. Elongated closed cells separated by complex walls of dislocations are developed during swaging and drawing. The yield strength, σ, of such material is related to the average cell width, l, by σ ~ l − 1 2 , in agreement with previous work on drawn tungsten and various drawn ferrous alloys.
Terminal and interstitial deletions of the long arm of chromosome 7: A review with five new cases

Sixteen cases of terminal deletions and 17 cases of interstitial deletions of the long arm of chromosome 7 have been reported to date. We present two new cases of the former and three of the latter. The somatic changes in these patients are tabulated and an update on the anomalies associated with the various cytogenetic entities is presented. Changes found in over one-third of patients with 7q terminal deletion syndrome include: developmental delay, pre- and postnatal growth retardation, generalized hypotonia, abnormal electroencephalograms with or without seizures, feeding problems in infancy, microcephaly, prominent forehead, ocular hypertelorism, eye defects, broad nasal bridge, bulbous nasal tip, auricular malformations, micrognathia, chest abnormalities, genital malformations in males, and abnormal palmar and plantar creases. Evidence for the localization of the Kidd blood group gene on chromosome 7 distal to band q32, as suggested by previous reports, is reviewed; we conclude that the evidence does not warrant placement of the gene in this region of the genome.
Response to Professor Altizer's “A New History and a New But Ancient God?”

Professor Altizer was kind enough to send me his essay-review of The Ecumenic Age. In my lengthy response to his courtesy I thanked him for his perceptive and brilliant study of my work, and I tried to clarify some points that seemed to worry him. When he communicated this letter to you, the three issues raised in it appeared of sufficient interest to you to have my answer published together with the review, provided my brief intimations of the problems were elaborated somewhat, but not too much, to become intelligible to a wider body of readers. In order to fulfill this condition, we agreed on the form of a letter to you which indeed does no more than spell out intimations which needed no spelling out in a private correspondence between scholars who know each other well. Well, here is the letter.
Correlates of academic performance among school-age African American males in public housing

Abstract This study contributes to ongoing effort to understand correlates of academic performance in school age African American male adolescents in public housing (N = 220). Guided by problem behavior theory (PBT), we examine the effects of depressive symptoms, anxiety sensitivity and delinquent behavior on academic performance. The effect of age and environmental factors is also assessed. Results provide partial support for PBT and suggest that delinquent behavior was positively related to academic performance while age and anxiety sensitivity were inversely related to the dependent variable. Although depressive symptoms was not related to the dependent variable, the interaction term indicated that when youth reported depressive symptoms below the 24 cut-off point age had no effect on their academic performance. Implications for policy and scholarship are presented.
Implementing state-space methods for multizone contaminant transport

Abstract The “well-mixed zone” approximation is a useful model for simulating contaminant transport in buildings. Multizone software tools such as CONTAM [1] and COMIS [2] use time-marching numerical methods to solve the resulting ordinary differential equations. By contrast, the state-space approach solves the same equations analytically [3] . A direct analytical solution, using the matrix exponential, is computationally attractive for certain applications, for example, when the airflows do not change for relatively long periods. However, for large systems, even the matrix exponential requires numerical estimation. This paper evaluates two methods for finding the matrix exponential: eigenvalue decomposition, and the Pade algorithm. In addition, it considers a variation optimised for sparse matrices, and compares against a reference backward Euler time-marching scheme. The state-space solutions can run several orders of magnitude faster than the reference method, with more significant speedups for a greater number of zones. This makes them especially valuable for applications where rapid calculation of concentration and exposure under constant air flow conditions are needed, such as real-time forecasting or monitoring of indoor contaminants. For most models, all three methods have low errors (magnitude of median fractional bias
Potentiometric phosphate-sensing system utilizing phosphate-binding protein

A phosphate-detection system has been developed which uses phosphate-binding protein (PBP) from Escherichia coli. PBP was immobilized on a sheet of nitrocellulose membrane by cross-linking and the membrane potential of the immobilized PBP was measured.. The response time of the system to phosphate was 5 min. The response was selective to phosphate among other anions. Under optimum conditions 0.1–1.5 mmol L–1 phosphate can be determined with this system.
Obesity due to high fat diet decreases the sympathetic nervous and cardiovascular responses to intracerebroventricular leptin in rats

Obesity is associated with an increase in plasma leptin levels primarily derived from enhanced expression of the leptin gene in the adipose tissue. Leptin levels and expression are higher in females than males. The main functions of leptin are to decrease food intake and increase sympathetic nerve activity, especially in the brown adipose tissue. The high levels of leptin in obese, female rats suggest leptin resistance. In this article we describe experiments designed to investigate the effect of the intracerebroventricular (i.c.v.) administration of leptin on lumbar sympathetic nerve activity (LSNA) and cardiovascular parameters in female rats fed a low fat diet (control), a high fat diet (obese), or high fat diet followed by a period of food restrictions (reduced). The i.c.v. leptin administration increased LSNA in control rats, but decreased it in obese rats. In weight reduced animals the LSNA response to leptin returned to control levels. The i.c.v. leptin increased the mean arterial pressure in control and wt. reduced rats, but not in obese animals. The heart rate did not respond to leptin in any animal group. These results suggest that obesity decreases the central nervous system (CNS)-mediated lumbar sympathetic nervous and cardiovascular responses to leptin and that these responses recover following food restriction and wt. reduction. We conclude that obesity is associated with a decreased CNS response to leptin leading to a decrease in leptin effects to increase the activities of the autonomic nervous and cardiovascular systems.
Political Influence in the 1990s: From Iron Triangles to Policy Networks

To assess the prospects of comprehensive health care reform during the Clinton administration, we must examine the changes that have occurred in the political and structural contexts in which reform is debated. The political context includes the status of the health care system itself as well as public attitudes and voting patterns associated with health care reform; it may be friendlier now to reform than it has been in any previous period, but it cannot on its own produce policy change. The structural context, the representational community of organized interests and government institutions, is the means by which politics is either thwarted or translated into action. Changes in these organized interests and in Congress have transformed the health care reform policy community from an "iron triangle" dominated by an antireform alliance of medicine, insurance, and business to a more loosely bound policy network in which a reform coalition may now be able to prevail, especially under the direction of an activist president like Bill Clinton. I consider three hypotheses: The first claims that, despite the apparent structural changes, the core power relationships will remain the same as in the past, and the antireform alliance either will continue to block policy change or will push through a reform program that protects its constituent interests. According to the second, the structural changes produce an atomization of power, making coalition building in support of reform impossible. The third and most plausible hypothesis proposes that the structural changes, in combination with the shift in politics and Clinton's election, have generated new opportunities for fundamental reform.
Size and Shape of Montmorillonite Crystallites

Spray drying dilute suspensions of bentonitic montmorillonite produces a powder that shows totally random orientation of the crystallites within a sample large enough to diffract X-rays. The powder is collected by an electrostatic precipitator and can be handled in the normal mounting processes without introducing preferred orientation. Electron micrographs show this powder to be composed on a small scale of thin, crumpled, and rolled films. The extremely small montmorillonite crystallites that make up the film are oriented with [001] directions perpendicular to the film surface. Orientation within the plane of the film is random as shown by selected area electron diffraction. Crumpling and rolling of the film is sufficient to make the orientation of [001] directions random in three dimensions in a large sample when X-ray diffraction is registered. The X-ray diffraction patterns all show diffraction maxima (both hk and 00l), and their relative intensities with respect to each other can be determined. The line broadening of the 06 and the 003 peaks was studied. The average crystallite size as calculated from the line broadening varied from six to eleven unit layers thick for four bentonitic montmorillonites. The average lateral dimension of crystallites varied from 140 A to 250 A. Ratios of lateral dimensions to thickness varied from 2.3 to 3.4.
Effectiveness of Virtual Reality Simulation Software in Radiotherapy Treatment Planning Involving Non-Coplanar Beams with Partial Breast Irradiation as a Model

Virtual reality simulation software (VRS - FocalSim Version 4.40 with VRS prototype, Computerized Medical Systems, St. Louis, MO) is a new radiation dose planning tool that allows for 3D visualizat...
Winter 2014 Issue Introduction: Teaching & Learning Articles Dominate This Issue

We have articles from four of our five sections in this last issue of 2014. Three of the six are from Teaching & Learning. In addition, we are announcing co-editor transitions in two of our section...
The Evolution and Persistence of Optimism in Litigation

Empirical evidence suggests that lawyers and litigants are systematically optimistic with respect to the outcome at trial. Using evolutionary game theory, this article seeks to provide a theoretical explanation for the persistence of the optimism bias. The adaptive force of optimism derives from its function as a commitment device in the pretrial bargaining stage. Optimistic lawyers, by credibly threatening to resort to costly litigation, succeed in extracting more favorable settlements. Therefore, market-selection forces and cultural transmission dynamics dictate an equilibrium with a positive level of optimism. Understanding the dynamics leading to optimism provides new insight regarding the different factors that influence the level of this cognitive bias. In particular, it is shown that the design of legal rules affects the equilibrium level of optimism, which in turn affects the relative efficiency of the different legal designs. Methodologically, by enabling a more systematic exploration of the perception-shaping role of the law, this article seeks to expand the conventional boundaries of behavioral law and economics. Copyright 2006, Oxford University Press.
Self-absorption corrections for gamma ray spectral measurements of 210Pb in environmental samples

Abstract Theoretical considerations and experimental data are used to demonstrate the basic behaviour of the self-absorption effect of a sample matrix in gamma ray spectrometry, particularly as it relates to the analysis of 210Pb in environmental media. The results indicate that it may not be appropriate to apply the commonly used self-absorption function in all cases.
Excretion of 17-ketosteroids by patients suffering from poliomyelitis.

SummaryThe 17-ketosteroids excreted into the urine by patients suffering from different types of poliomyelitis showed no significant variations from normal excretion levels.
High-temperature stability of a polyimide film

Polyimide (PMDA-ODA) films were analyzed by mass spectroscopy to determine their high-temperature stability. Using a high-resolution instrument, the identity of the low-molecular-weight evolved gases was confirmed. With a semiquantitative technique, the effect of a vacuum pre-bake was shown to reduce outgassing appreciably during subsequent treatment at high temperature. Subjection of the films to moisture did not affect their thermal stability. Low-temperature processing (240°C vs 400°C) reduced gaseous evolution by an order of magnitude.
Developing flow and particle deposition in horizontal elutriators and semi-dispersive aerosol centrifuges

Abstract In the past, the deposition patterns of monodisperse aerosols in semi-dispersive aerosol analyzers as the horizontal elutriator or the Goetz aerosol centrifuge have been derived theoretically under the assumption that the streamline flow through the duct has a fully developed velocity profile. This paper gives a general solution for the deposit concentration of monodisperse aerosols with no restrictions as to the type of streamline flow. It shows that developing flow profiles are immaterial in horizontal elutriators where the particle concentration still remains constant along the length of the deposit. For existing centrifugal devices, the developing profile causes small changes amounting to a moderate correction of the theoretical results obtained for constant flow profiles, but the basic characteristics of the deposit concentration patterns of the simple theory still prevail. Actual deviations between experimental findings and theoretical computations in case of the Goetz centrifuge are not due to the neglect of a developing flow by the basic theory, but originate from a slow double-vortex flow in the cross-sectional plane of the duct effecting a redistribution of the particle concentration across the deposit. This motion is caused by additional external forces, in particular Coriolis forces, which the basic theory cannot account for.
Cocaine modulates cytokine and enhances tumor growth through sigma receptors

Abstract Sigma receptors are intracellular receptors that interact with a variety of psychotropic ligands, including cocaine. Administration of cocaine to mice promoted the in vivo growth of a syngeneic lung cancer cell line and identical effects were observed with PRE 084, a selective sigma 1 receptor agonist. Increased tumor growth was accompanied by an increase in IL-10 and a decrease in IFN-γ production in splenocytes and at the tumor site. The tumor-promoting effects produced by both cocaine and PRE 084 were abrogated by administration of specific antibodies to IL-10, or by administration of a sigma 1 receptor antagonist. We conclude that sigma 1 receptor ligands, including cocaine, augment tumor growth via a cytokine-dependent, receptor-mediated mechanism that involves regulation of T helper 1/T helper 2 cytokine balance.
A quantitative ultrastructural analysis of the synaptic population in the sacral visceral gray.

Abstract The synaptic distribution in the sacral visceral gray of the cat was examined. Synaptic complexes exhibiting a distinct membrane specialization were identified and classified according to vesicle type and number. Boutons containing clear spherical vesicles (S type) account for more than 63% of the synaptic contacts on both cell bodies and dendrites. Terminals containing three or more granular vesicles (GS type) comprise between 23 and 31% of the synapses in the nucleus. F boutons are less frequently seen (3–6%) as are T type boutons (1–2%). Presynaptic terminals containing a predominance of dense core vesicles (GG type) constitute less than 1% of the total synapses in this neuropil and are found only on dendrites. Nerve cell bodies receive approximately five synaptic contacts per 100 μm of postsynaptic membrane. Large and medium size dendrites are contacted by an average of seven boutons per 100 μm of postsynaptic membrane and small dendrites have the highest distribution (approximately 12 per 100 μm). Comparison of the percentage distribution of various types of synapses in this nucleus reveals little variation between cell bodies and dendrites. However, expression of the synaptic population as boutons per 100 μm of available postsynaptic membrane clearly illustrates intranuclear differences in synaptic distribution not seen in percentage type comparisons.
The role of 5HT1A receptors in the modulation of the acoustic startle reflex in rats

The modulatory role of serotonin (5-HT) on the acoustic startle reflex was studied using 5-HT receptor agonists and antagonists. 8-Hydroxy-2-(di-n-propylamino) tetralin (8-OHDPAT) (1,2 and 4 mg/kg, SC) and 5-methoxy-N,N-dimethyltamine (5-MeODMT) (1,2 and 4 mg/kg, IP), putative 5-HT1a receptor agonists, increased the magnitude of the startle reflex, while quipazine (5, 10 and 20 mg/kg, SC), an agonist with mixed 5-HT2 and 5-HT1b receptor activity, decreased startle responsiveness. Pretreatment of rats with ketanserin (1, 2 and 4 mg/kg, SC), a 5-HT2 receptor antagonist, had no significant effect on the activity of 8-OHDPAT, 5-MeODMT, or quipazine. Metergoline (0.25, 0.5, 1 and 2 mg/kg, SC), a mixed 5-HT1/5-HT2 receptor antagonist attenuated the augmentation of the reflex by 8-OHDPAT and 5-MeODMT and the suppression produced by quipazine. At the doses used, metergoline produced a non-dose-dependent increase in startle, while ketanserin had no effect. None of the agents specifically affected the bility of a prepulse stimulus to inhibit the acoustic startle response. These data suggest that 5-HT1a and 5-HT1b receptors play opposite roles in the modulation of the acoustic startle response and that 5-HT plays little, if any, role in the prepulse inhibition of the acoustic startle response.
Orthogonal functionalization of cyclopenta[hi]aceanthrylenes.

A synthetic strategy to prepare 2,7- or 4,9-functionalized cyclopenta[hi]aceanthrylenes that are capable of Suzuki cross-coupling reactions is demonstrated. This method has been utilized to create a series of thiophene derivatized compounds that were subsequently used to investigate the role of substitution pattern on the photophysical and electronic properties of cyclopenta[hi]aceanthrylenes. The orthogonal functionalization provides access to unique substitution patterns (e.g., cruciform-like architectures) and materials with small optical band gaps (1.22–1.97 eV).
A notable phenomenon recapitulated. A fusion product of a murine lymphoma cell and a leukemia virus-neutralizing antibody-producer host plasma cell formed spontaneously and secreting the specific antibody continuously.

In the mid-1960s the #620 cell passage line of a murine lymphoma-leukemia was developed at the Section of Clinical Tumor Virology and Immunology, Department of Medicine, The University of Texas M. D. Anderson Hospital in Houston, TX. The diploid lymphoma cells released a retrovirus and were antigenic in young adult Swiss (YAS) mice. Small lymphoma cell inocula were rejected with immunity acquired against large inocula of lymphoma cells. Tissue sections revealed the “starry sky” configurations. In one of the tissue cultures set up from lymphoma #620, a cell line consisting of large round poly- or tetraploid cells arose and was referred to as lymphoma cell line #818. The #818 cells grew in suspension cultures and in the form of large, lethal ascitic tumors in YAS mice. Diploid #620 lymphoma cells stained for retroviral antigens; #818 cells stained both for retroviral antigens and immunoglobu­lins. Fluids withdrawn from #818 cultures neutralized the leukemia virus in spleen focus assays. Immunoglobulin preci...
Percentage of emergency medicine residency graduates who got their first choice of jobs did not change between 1995 and 1997.

The objective of this study was to compare the number of emergency medicine (EM) graduates unable to find a job in the city/area of their first choice in 1995 and 1997. Self-administered questionnaires were distributed to EM residents who graduated in both 1995 and 1997. The survey ascertained resident's practice city and state, whether their job was in the city/area of first choice and how satisfied they were with their practice selection. Eighty (83%) programs and 507 (70%) of eligible residents participated. Thirty-eight percent of graduates chose to practice in the city or metropolitan area where they trained and 75% of respondents were very satisfied with their practice selection. Nineteen percent stated they would not be practicing in the city/area of their first choice; one-third indicated there were no jobs available and two-thirds stated that jobs were available but not desirable. These numbers were similar to the 1995 data (P = .79). Job selection was more important than liking (P < .001) or having lived in (P < .001) a desired city/area of practice location. In conclusion, 1997 EM residency graduates were as successful as 1995 graduates in obtaining their first choice of jobs.
Guide to gas hydrate stability in various geological settings

Abstract The presence of clathrates (gas hydrates) is well established observationally in the offshore region of the South Caspian Basin, as well as in many other regions of the world. Hydrates of fixed composition can exist under particular pressure-temperature conditions. However, under the impact of neotectonic processes, those conditions can change. Part, or all, of the mass of hydrates can then be dissociated and released as gas and water. The dissociation can take place gradually, or explosively, depending on how fast the pressure drops or temperature increases. Five major variations of hydrate evolution are considered to illustrate possible patterns of behavior caused by variation of geological conditions : (1) Variations in hydrate existence conditions due to sediment and mud redeposition : earthquakes, volcanic eruptions, and other processes, can release part of the sediments from a sloping sea bottom and transport them to be redeposited in other places, thereby changing pressure conditions at the top of a hydrate layer. (2) Variations in hydrate existence conditions due to glacial-interglacial conditions : removal of ice cover not only decreases overlying pressure, but also allows water temperatures overlying the sediments to increase. (3) Variations in hydrates due to sea-level rise and fall. (4) Enrichment of ethane in hydrates as a consequence of varying neotectonic conditions. (5) Evaporation and reformation of hydrates in aeolian conditions due to winter cooling and summer heating. Hydrates can be a potential explosive hazard for exploration rigs, production platforms and pipelines, especially in deep water conditions. These geological patterns of instability should therefore be considered when potential hazards are assessed. © 1998 Elsevier Science Ltd. All rights reserved.
Promotion of endometriosis by 2,3,7,8-tetrachlorodibenzo-p-dioxin in rats and mice: time-dose dependence and species comparison.

In the disease of endometriosis, endometrial tissue grows outside the uterus, usually in the peritoneal cavity. Rodent models of endometriosis allow a way to reproduce the disease, evaluate effects of chemicals, and study mechanisms. Twenty-one days prior to induction surgery which produces endometriosis, female Sprague-Dawley rats and B6C3F1 mice were pretreated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) at 0, 3 or 10 micrograms TCDD/kg. Animals were treated again at the time of surgery and at 3, 6, and 9 weeks following surgery. Evaluations were made at 3, 6, 9, and 12 weeks postsurgery. TCDD produced a dose-dependent increase in endometriotic site diameter when all time points were pooled within each dose in rats and a dramatic increase in site diameter in mice at 9 and 12 weeks. In rats but not mice, ovarian weight was decreased at 9 and 12 weeks, the occurrence of persistent vaginal estrus was increased at these times, and histological evaluation of the ovaries revealed ovulatory arrest at 12 weeks. In both species, thymic antrophy, indicating immune dysfunction, and hepatomegaly were observed as consequences of TCDD exposure. Body weight was reduced in rats but not in mice. Histological evaluations of endometriotic sites revealed fibrosis in control rats, necrotic and inflammatory changes in the sites from TCDD-treated rats, and predominantly fibrotic changes in sites from TCDD-treated mice. Differences observed between the rat and the mouse with respect to (a) the magnitude of the effect on endometrial site diameter (rats mice) that may be based on the partial antiestrogenicity of TCDD, and (c) evidence that mice and rats differ in their immune response to TCDD suggest that the mechanisms mediating TCDD's action to promote endometriosis are complex and may be different in rats and mice. The mouse may be a better model for future studies necessary to elucidate these mechanisms.
Perceiving Stability in a Changing World: Combining Shots and Intergrating Views in Motion Pictures and the Real World

One of the central debates in the study of media concerns the relationship between our perception of real-world events and mediated events such as motion pictures. A number of authors have argued convincingly that both rely on similar natural perceptual processes. Here we extend this argument by reviewing research on scene perception showing that the similarity between film and natural perception includes a common tendency to perceive events as continuous in the face of large view-to-view inconsistencies. This research shows that observers are frequently unable to detect large unexpected changes that occur between views, even in objects within their focus of attention. This is true both in mediated stimuli such as motion pictures and during staged real-world interactions. Thus, perception of continuity may be an inference that proceeds in spite of impossible between-view changes, both in motion pictures and real-world scenes.
Determination of Viscous Damping for Low Frequency Motions of Floating Structures

ExxonMobil Upstream Research Company developed an advanced model test method to determine reliable damping values for predicting low frequency motions of an FLNG barge and an LNG carrier [1]. An inertial compensation system was introduced in the test to confidently isolate the relatively very small viscous damping force from the total measured forces in the forced oscillation tests. In the system, the spring stiffness in the restoring mechanism was tuned such that the test was done near resonance. This method has been successfully applied to ExxonMobil forced oscillation tests to measure damping of deeply submerged, double body models. Three types of motions were generated in the tests: sinusoidal motions, decay motions and motions with multiple frequencies. In this paper, the authors attempt to correlate the damping obtained from decay tests and from tests with motions of multiple frequency components. Findings from this work help determine damping for predictions of full scale motion in irregular waves.Copyright © 2011 by ASME
Analysis of gating transitions among the three major open states of the OpdK channel.

OpdK is an outer membrane protein of the pathogenic bacterium Pseudomonas aeruginosa. The recent crystal structure of this protein revealed a monomeric, 18-stranded β-barrel with a kidney-shaped pore, whose constriction features a diameter of 8 A. Using systematic single-channel electrical recordings of this protein pore reconstituted into planar lipid bilayers under a broad range of ion concentrations, we were able to probe its discrete gating kinetics involving three major and functionally distinct conformations, in which a dominant open substate O2 is accompanied by less thermodynamically stable substates O1 and O3. Single-channel electrical data enabled us to determine the alterations in the energetics and kinetics of the OpdK protein when experimental conditions were changed. In the future, such a semiquantitative analysis might provide a better understanding on the dynamics of current fluctuations of other β-barrel membrane protein channels.
Staining of composite and microfilled resin with stannous fluoride

M arginal breakdown and discoloration have often been cited as major problems associated with toothcolored restorative materials. Studies have substantiated the potential for composite resin restorations to stain. A clinical study indicated a change in color match in approximately 60% of composite restorations over a 2-year period.’ In a laboratory study coffee and soy sauce have also been shown to stain composite resin to a significantly greater degree than tea or cola beverages.* This study determined if a single application of various stannous fluoride preparations stains or discolors composite and microfilled resin restorative materials.