cssi/SciSciGPT-SciSciNet huggingface dataset:
Mechanisms of Chromosomal Instability

Most solid tumors are aneuploid, having a chromosome number that is not a multiple of the haploid number, and many frequently mis-segregate whole chromosomes in a phenomenon called chromosomal instability (CIN). CIN positively correlates with poor patient prognosis, indicating that reduced mitotic fidelity contributes to cancer progression by increasing genetic diversity among tumor cells. Here, we review the mechanisms underlying CIN, which include defects in chromosome cohesion, mitotic checkpoint function, centrosome copy number, kinetochore–microtubule attachment dynamics, and cell-cycle regulation. Understanding these mechanisms provides insight into the cellular consequences of CIN and reveals the possibility of exploiting CIN in cancer therapy.
Successful revision of portoenterostomy in an infant with biliary atresia

We present a case report of a boy with biliary atresia who, after hepatoportoenterostomy performed on day 21 of life, had immediate resolution of cholestasis and remained anicteric until 3.5 months of age. He then abruptly developed acholic stools. Nuclear medicine imaging study showed no excretion. Broad-spectrum antibiotics and corticosteroids were administered but did not lead to clinical improvement; a surgical revision of the original anastomosis was undertaken at 4 months of age. At 14 months of age, the child is anicteric and growing well. In this case, successful revision of hepatoportoenterostomy averted the need for liver transplantation.
Does the brain shrink as the waist expands

Recent studies suggest that being overweight or obese is related to worse cognitive performance, particularly executive function. Obesity may also increase the risk of Alzheimer's disease. Consequently, there has been increasing interest in whether adiposity is related to gray or white matter (GM, WM) atrophy. In this review, we identified and critically evaluated studies assessing obesity and GM or WM volumes either globally or in specific regions of interest (ROIs). Across all ages, higher adiposity was consistently associated with frontal GM atrophy, particularly in prefrontal cortex. In children and adults <40 years of age, most studies found no relationship between adiposity and occipital or parietal GM volumes, whereas findings for temporal lobe were mixed. In middle-aged and aged adults, a majority of studies found that higher adiposity is associated with parietal and temporal GM atrophy, whereas results for precuneus, posterior cingulate, and hippocampus were mixed. Higher adiposity had no clear association with global or regional WM in any age group. We conclude that higher adiposity may be associated with frontal GM atrophy across all ages and parietal and temporal GM atrophy in middle and old age.
Reduction of tip-sample contact using dielectrophoretic force scanning probe microscopy

Dielectrophoretic force microscopy is shown to allow for facile noncontact imaging of systems in aqueous media. Electrokinetic tip−sample forces were predicted from topography measurements of an interface and compared with experimental images. Correlation function and power spectral density analyses indicated that image feedback was maintained without mechanical contact using moderate potentials (e.g., ∼18 nm off the surface for a 7-Vpp, 100-kHz waveform). The applied dielectrophoretic force and the corresponding increase in effective tip radius were predictably adjusted by changing the peak potential.
Breast cancers: Estrogen and progesterone receptor status as a predictor of in vitro chemotherapeutic response☆

Although clinical observations have shown that estrogen receptor-positive (ER+) breast tumors are more responsive to hormonal therapy than ER-negative (ER−) tumors, it remains controversial whether ER status can predict chemotherapeutic response. To determine if there was any correlation between estrogen and progesterone values and in vitro chemosensitivity to various anticancer drugs, clonogenic (CA), estrogen (ERA), and progesterone (PRA) assays on breast cancers were performed on 100 patients. Clonogenic assays were performed using the double-layer soft agar technique with continuous drug exposures. ERAs and PRAs were performed using the charcoal-coated dextran method. Chemosensitivity was defined as 50% inhibition of colony formation. ERA was considered positive if ⩾5 fmole/mg cytosol and PRA positive if ⩾10 fmole/mg cytosol. Significant tumor growth (> 30 colonies/plate) was achieved in 81100 assays. ERA and PRA values were not predictive of colony formation in vitro. Of all agents or combinations of agents tested (L-PAM, 5-FU, MTX, adriamycin, vinblastine, cis-plat, FAC, CMF), only the response to 5-FU correlated significantly with ERA. Eight of 11 (73%) of the ER− tumors were sensitive to 5-FU, whereas only 620 (30%) of ER+ tumors were sensitive (P < 0.05). ER− tumors were also more likely to be sensitive to CMF (P = 0.09) and adriamycin (P = 0.07) than ER+ tumors. PRA values were not predictive of chemosensitivity, nor did combining PRA and ERA enhance the predictive value of ERA alone.
L-serine potentiates the mitogenic effects of growth factors on cultured human keratinocytes.

Abstract l-Serine increased the growth of passaged human foreskin keratinocytes in terms of DNA and protein per dish of cells, and potentiated the mitogenic effects of serum and epidermal growth factor, and also insulin, keratinocyte growth factor, and a bovine pituitary extract. The effects of serine were apparent with as little as 0.05 mm. The stimulatory effects of these various growth factors were additive, without synergism. Exposure to l-[ 3 H]serine resulted in labeling of the phospholipids phosphatidyl (Ptd) serine, Ptd ethanolamine, sphingomyelin, and, to a slight extent, Ptd choline. The time course of labeling suggested (1) synthesis of Ptd serine was initiated; (2) Ptd serine was converted to Ptd ethanolamine; (3) little methylation of Ptd ethanolamine to form Ptd choline took place. Separation of nonradioactive phospholipids and phosphorus assay of individual lipids showed that serine-supplemented cells had only slightly increased content of Ptd serine and Ptd ethanolamine. The significance of these for activation of protein kinase C is discussed.
Thermodynamic analysis of intracellular ice recrystallization in mouse oocytes

Abstract In a recent article published in Cryobiology, Seki and Mazur [9] performed kinetic analysis to investigate the physicochemical mechanism of the intracellular ice formation in mouse oocytes subjected to rapid cooling. Based on their results, the authors calculated the activation energy for the ice recrystallization process to be 27.5 kcal/mol. In this letter, we report our analysis of the result in terms of the transition-state theory to show that the process is unfavorable in terms of enthalpy but favorable in terms of entropy accompanying molecular expansions. This report is expected to evoke interests in applying thermodynamics to the investigation of the intracellular ice formation.
Refining concept maps: Methodological issues and an example

Abstract This paper describes a concept mapping exercise conducted with a group of public school teachers for the purpose of formulating a plan to integrate computer technology into a conventional educational setting. The exercise involved the generation of conceptual entities through a structured brainstorming session, and a session in which participants subjectively rated the brainstormed entities according to perceived similarities between them. This was followed by a multidimensional scaling and hierarchical cluster analysis of the similarity ratings, and interpretation of the map. Initial results indicated that there was a confounding effect on the final map because of perceived semantic groupings based on surface characteristics which were not germane to the intended focus of the conceptualization exercise. The paper describes a method that was used to control the effects of these strong, but experimentally irrelevant, category-based associations which subjects in this study made among certain items in a subset of the data. The initial map is presented along with the final map which shows the effect of the attempt to correct for this methodological artifact.
Prediction Intervals for Artificial Neural Networks

Abstract The artificial neural network (ANN) is becoming a very popular model for engineering and scientific applications. Inspired by brain architecture, artificial neural networks represent a class of nonlinear models capable of learning from data. Neural networks have been applied in many areas, including pattern matching, classification, prediction, and process control. This article focuses on the construction of prediction intervals. Previous statistical theory for constructing confidence intervals for the parameters (or the weights in an ANN), is inappropriate, because the parameters are unidentifiable. We show in this article that the problem disappears in prediction. We then construct asymptotically valid prediction intervals and also show how to use the prediction intervals to choose the number of nodes in the network. We then apply the theory to an example for predicting the electrical load.
Normalized water-leaving radiance: revisiting the influence of surface roughness

Many spaceborne sensors have been deployed to image the ocean in the visible portion of the spectrum. Information regarding the concentration of water constituents is contained in the water-leaving radiance—the radiance that is backscattered out of the water and subsequently propagates to the top of the atmosphere. Recognizing that it depends on the viewing and Sun geometry, ways have been sought to normalize this radiance to a single Sun-viewing geometry—forming the normalized water-leaving radiance. This requires understanding both the bidirectional nature of the upwelling radiance just beneath the surface and the interaction of this radiance with the air–water interface. I believe that the latter has been incorrectly computed in the past when a water surface roughened by the wind is considered. The presented computation suggests that, for wind speeds as high as 20 m/s, the influence of surface roughness is small for a wide range of Sun-viewing geometries, i.e., the transmittance of the (whitecap-free) air–water interface is nearly identical (within 0.01) to that for a flat interface.
Alternative Water Resources for Utility-scale Solar Energy Development☆

Abstract Electricity generated from solar energy continues to increase throughout the United States, and several states in the southwestern United States are interested in the development of utility-scale solar energy to meet their established renewable energy portfolios. Water use by utility-scale solar facilities can be quite significant for some technologies, however, which is problematic considering that the best location for solar energy development—the southwestern United States—tends to be an arid environment. The goal of this study was to examine the feasibility of using alternative water resources (reclaimed wastewater and produced water in this study) to meet water demands for utility-scale solar energy development, focusing specifically on Solar Energy Zones (SEZs) and Competitive Renewable Energy Zones (CREZs). Our results indicate that, on average, 100% of the projected demand for water at most SEZs and CREZs could be met by reclaimed wastewater if photovoltaics (PV) are installed. If concentrating solar power (CSP) is installed, fewer SEZs could meet their potential water demand from alternative sources. Only 10 of the CREZs were located near sources of produced water, but of those, 100% of the water demand at the CREZ was met in 8 cases, regardless of the technology installed. Overall, the results from this analysis indicate that alternative waters can play a prominent role in meeting water demand at solar zones in the arid southwest.
INDUCTION OF ENDOMETRIAL PEROXIDASE SYNTHESIS AND SECRETION BY ESTROGEN AND ESTROGEN ANTAGONIST

Synthesis of peroxidase was induced in the uterine epithelium of immature rats by multiple doses over a 24–96-h period of either 17 β-estradiol, the estrogen-antagonist Parke-Davis CI-628, or a combination of estradiol plus antagonist. Endogenous peroxidase activity first appeared in the cisternae of the rough endoplasmic reticulum of surface epithelial and glandular cells within 24–48 after the initial injection. Uterine peroxidase activity was also visible in the cisternae of the Golgi apparatus, in Golgi-derived secretory granules, and within the uterine and glandular lumen. Some cells of the epithelium produced little or no peroxidase, even after 96 h. Whereas the antagonist appeared to induce synthesis and secretion of peroxidase, neither the antagonist alone nor the combined treatment (estradiol plus antagonist) reproduced the estradiol-mediated growth in organ size and increased lumen diameter.
Hyper-spectral imaging in scanning-confocal-fluorescence microscopy using a novel broadband diffractive optic

Abstract In this paper, we demonstrate hyper-spectral imaging of fluorescent microspheres in a scanning-confocal-fluorescence microscope by spatially dispersing the spectra using a novel broadband diffractive optic, and applying a nonlinear optimization technique to extract the full-incident spectra. This broadband diffractive optic has a designed optical efficiency of over 90% across the entire visible spectrum. We used this technique to create two-color images of two fluorophores and also extracted their emission spectra with good fidelity. This method can be extended to image both spatially and spectrally overlapping fluorescent samples. Full control in the number of emission spectra and the feasibility of enhanced imaging speed are demonstrated as well.
Energy harvesters with high electromagnetic conversion efficiency through magnet and coil arrays

This paper presents a new technique of converting mechanical energy to electrical energy that can be used to harvest mW - W power level from a vibrating surface of tens - hundreds microns amplitude. The technique uses an array of alternating north- and south-orientation magnets to enhance magnetic flux change by more than an order of magnitude. Experimental results show that a microfabricated energy harvester of 20mm×5mm×0.9mm (=0.09cc) weighing 0.5 gram generates an induced electromotive force (EMF) of Vp-p =30mV with 2.6μW power output (into 10.8Ω load) when it is vibrated at 290Hz with vibration amplitude of 11μm. Its macroscale version, that is scaled up to 51mm×51mm×10mm (=26cc) weighing 90 gram, generates an EMF of Vp-p=22V with 158mW power output (into 96Ω load) when it is vibrated at 82Hz with vibration amplitude of 414μm, and lights an incandescent light bulb.
An improved cost function for static partitioning of parallel circuit simulations using a conservative synchronization protocol

Distributing computation among multiple processors is one approach to reducing simulation time for large VLSI circuit designs. However, parallel simulation introduces the problem of how to partition the logic gates and system behaviors of the circuit among the available processors in order to obtain maximum speedup. A complicating factor that is often ignored is the effect of the time-synchronization protocol (conservative [1] or optimistic [2]). Inherent in the partitioning problem is the question of how to effectively measure the relative quality of a partition. This paper describes an objective cost function for measuring the relative quality of a task partition that includes a synchronization factor for a conservative NULL-message protocol. A graph-based partitioning tool based on this cost function is used to perform the static task allocation for parallel simulation of a structural VHDL circuit. Results for two 1000 – 4000 gate circuits demonstrate that the additional consideration of the synchronization protocol in the cost function generates partitions that exhibit improved speedup.
Basal forebrain neurons undergo somatal and dendritic remodeling during postnatal development: a single-section Golgi and choline acetyltransferase analysis.

Abstract In an attempt to determine whether or not morphologic changes occur in the cholinergic basal forebrain during postnatal development, Golgi-impregnated and choline acetyltransferase-positive cells were examined in adult and postnatal day (P) 10, 14, 18, and 27 rats. Light microscopic analyses revealed progressive increases in cross-sectional cell body area, number of primary dendrites, number of dendritic branch points, and length of the longest dendrite that peaked at P18 and thereafter decreased to smaller adult values with the exception of dendritic length which monotonically increased until adulthood. These findings suggest that extensive remodeling of cholinergic neurons in the basal nuclear complex occurs even at relatively late postnatal periods.
Comparative aspects of the biology of naturally produced and hatchery-reared Atlantic salmon smolts (Salmo salar L.)

Abstract The age composition of naturally produced (wild) smolts in the Burrishoole river system has given a consistent proportion of > 90% as 2+, with the remainder divided equally between 1+ and 3+. Hatchery-reared smolts produce 40% as 1+ and the remainder as 2+; the proportion of 1+ smolts can be increased by the use of warmed water in early stages of the life history. The size and condition of wild smolts has also proved to be consistent each year but they are considerably smaller than hatchery-reared smolts of comparable age. Grilse derived from both wild and hatchery-reared 1+ smolts are smaller than those from 2+ smolts. The survival rate from ova to wild smolts has averaged 0.61% over the past 10 years, compared with almost 50% for reared smolts. Returns to fresh water at the grilse stage are almost four times better for wild than reared smolts. Up to 81% exploitation of grilse from reared smolts by coastal nets has been calculated from coded-wire tagging results. No significant straying has occurred from either wild or reared smolts but the latter make repeated attempts to rediscover their homing point when upstream of it. Smolt rearing has given rise to abnormalities such as “giant” smolts and vertebral compaction, not reported in wild stocks. From 20 to 50% of the reared parr population are precocious males in their second freshwater winter.
Object Lessons: Workplace Artifacts as Representations of Occupational Jurisdiction1

While the development and control of professional jurisdictions has been well studied, less is known about the way in which occupational jurisdictions are enacted within organizations. This article suggests that one can gain insight about such dynamics through analyzing occupational communities’ use of organizational artifacts. This article describes the ways in which two artifacts—engineering drawings and machines—mediate the relations of engineers, technicians, and assemblers in a manufacturing firm. These artifacts are useful in problem solving across boundaries. At the same time, authority over these objects can reinforce or redistribute task area boundaries, and by symbolizing the work of occupational groups, the objects also represent and strengthen beliefs about the legitimacy of a group’s work.
Risk Behaviors and Health Care Utilization Among Homeless Youth: Contextual and Racial Comparisons

This study analyzes survey and focus group data from 54 homeless youth from a drop-in center and residential shelter in the Los Angeles area. Youth from the drop-in center reported higher levels of risk-taking behaviors as well as less access, lower quality of care, and overall more negative views regarding health care utilization than those from the residential shelter. Effective interventions targeting homeless youth must be sensitive to the fact that this vulnerable population is heterogeneous. No single approach will address the specific needs, circumstances, and perspectives of all subgroups in the target population, necessitating a multifaceted design.
Sex-associated quantitative differences in the plasma esterases of inbred mice.

The presence of sex-associated quantitative differences in 4 of the plasma •esterases of C57BL/6 mice was determined using the zymogram technique with disc •electrophoresis in acrylamide gel. The levels •of 4 of the esterases are controlled by testos- terone and may be manipulated by hormone treatment, gonadectomy, or a combination of both. A testosterone-like effect of estradiol was also found in one of the esterase bands. No quantitative plasma esterase differences be- tween sexes were observed in prepubescent mice and no qualitative esterase differences were found between the sexes of adult mice of the same strain. (Endocrinology 78: 655, 1966) V ARIOUS reports have appeared in the literature concerning the protein and enzyme differences between the sexes in various species of animals. Dimopoullos and Schrader (1) have shown that male cattle have more /3-globulin and 7-globulin and less a-globulin glycoprotein than females. Espi- nosa et at. (2) have reported sex-associated differences in the alpha-1, alpha-2 and beta serum globulins of mice, while Bond (3) has demonstrated a protein in rat liver that is quantitatively under the control of testos- terone. Allen and Hunter (4) have shown that 5 esterases in the mouse epididymis are affected by testosterone. We (5) have re- cently shown that marked quantitative differences exist between the sexes of various strains of inbred mice in several of the ester- ases in mouse plasma separated by disc electrophoresis in acrylamide gel. Since these differences were not apparent in mice less than 3 weeks of age, a study of the effects of age and sex hormones was carried out in in- tact gonadectomized mice.
Functional characterization of insulin and IGF-I receptors in chicken lens epithelial and fiber cells.

Insulin and insulin-like growth factor I (IGF-I) play a role in lens cell growth and development. The binding of these hormones to their respective receptors with its concomitant signal transduction is an important step in these cellular processes. Hormone binding to adult chicken lens insulin and IGF-I receptors, partially purified from epithelial and fiber cells, was studied to examine this activity in lens. The associated stimulation of receptor-mediated tyrosine kinase by the hormones was also studied. At an insulin concentration of 0.02 nM, specific binding was similar for epithelial and fiber receptor preparations (Epi= 0.23 ± 0.03 fmol, Fib= 0.19 ± 0.02 fmol). Displacement studies revealed that there was also no difference between epithelial and fiber receptor preparations in the concentration of insulin necessary for half maximal displacement of specific [125I]-insulin binding (IC50: Epi= 0.32 nM ± 0.07 nM, Fib= 0.31 nM ± 0.05 nM). Comparison of IGF-I (0.02 nM) binding to receptor preparations fro...
Learning diffeomorphism models of robotic sensorimotor cascades

The problem of bootstrapping consists in designing agents that can learn from scratch the model of their sensorimotor cascade (the series of robot actuators, the external world, and the robot sensors) and use it to achieve useful tasks. In principle, we would want to design agents that can work for any robot dynamics and any robot sensor(s). One of the difficulties of this problem is the fact that the observations are very high dimensional, the dynamics is nonlinear, and there is a wide range of “representation nuisances” to which we would want the agent to be robust. In this paper, we model the dynamics of sensorimotor cascades using diffeomorphisms of the sensel space. We show that this model captures the dynamics of camera and range-finder data, that it can be used for long-term predictions, and that it can capture nonlinear phenomena such as a limited field of view. Moreover, by analyzing the learned diffeomorphisms it is possible to recover the “linear structure” of the dynamics independently of the commands representation.
Role of cyclic AMP in the actions of cannabinoid receptors

Abstract Cannabinoids, including Δ9-tetrahydrocannabinol (THC), bind to receptors that couple to G i o - proteins and inhibit adenylyl cyclase. However, like other G-protein-coupled receptors, cannabinoid receptors are also coupled to other effector systems. This review examines the characteristics of the cannabinoidG-protein-adenylyl cyclase system, and explores the role of cyclic AMP in mediating effects of these drugs. Several conclusions emerge from this research. First, the principal actions of cannabinoids are mediated through G-protein-coupled receptors, and the intracellular signaling mechanism that initiates cellular response of cannabinoids is activation of G-proteins. Second, cannabinoid-inhibited adenylyl cyclase is only one of several different effectors coupled to these receptors, and different effectors may be used for different types of responses. Third, cannabinoid inhibition of adenylyl cyclase plays an important role in several aspects of cannabinoid function, including modulating conductance at a voltage-dependent K+ channel (“A” current) in the hippocampus, thus providing an effective rationale for behavioral effects of cannabinoids mediated in this region. Other functions of this system may include production of long-term changes in gene expression by inhibition of cyclic AMP response elements on strategic genes, and inhibition of anandamide synthesis, thus mediating some of the long-term effects of cannabinoids on neuronal function.
Protein transport via the cpTat pathway displays cooperativity and is stimulated by transport-incompetent substrate

Kinetic analyses of cpTat-mediated protein transport across the thylakoid membrane were conducted, revealing three important characteristics of this translocation pathway. First, transport via the cpTAT system displays a non-Michaelis–Menten, sigmoidal rate–substrate relationship with an apparent Hill coefficient of 1.80, indicative of positive homotropic cooperativity. Second, the presence of transport-incompetent substrates was found not to competitively inhibit the translocation of transport-competent substrates. However, the presence of low concentrations of transport-incompetent protein enhances the transport of wild type substrate. Together, these findings suggest that interaction between Tat machinery components and both transport-competent and transport-incompetent protein may elicit a cooperative effect on the translocation rate.
Basic fibroblast growth factor decreases elastin gene transcription through an AP1/cAMP-response element hybrid site in the distal promoter.

Previous studies demonstrated that basic fibroblast growth factor (bFGF) decreases elastin gene transcription in pulmonary fibroblasts. In this study we pursue the identification of the element and the trans-acting factors responsible. Gel shift analyses show that bFGF increases protein binding to a sequence located at −564 to −558 base pairs (bp), which possesses homology to both AP1 and cAMP-response consensus elements yet displays a unique affinity for heterodimer binding. Site-directed mutation of the −564- to −558-bp sequence results in an increase in promoter activity and abrogates the effect of bFGF. Western blot analysis shows that bFGF induces a sustained increase in the steady-state levels of Fra 1, and co-transfection of a Fra 1 expression vector with an elastin promoter reporter construct results in an inhibition of elastin promoter activity. Overall the results suggest that bFGF represses elastin gene transcription by increasing the amount of the Fra 1 that subsequently binds to the −564- to −558-bp as a heterodimer with c-Jun to form an inhibitory complex. We propose that the identified bFGF response element can serve to down-regulate elastin transcription in elastogenic cells and, conversely, can serve to up-regulate elastogenesis in cells where endogenous bFGF signaling is attenuated or altered.
Gender, Male Homosexuality, and Power in Colonial Yucatán

Scholars have been studying the history of homosexuality for two decades, but only rarely have they ventured beyond the study of homosexuality in modern Europe and the United States. In the past several years, others have begun to challenge the Eurocentric biases of these works. One set of issues often overlooked by both Latin American historians and historians of homosexuality in general is the connection between homoeroticism, colonialism, and discourse among the Maya of Yucatan. Examining the colonial years, one can establish a variety of power dynamics at work. The Spaniards asserted their own power in an attempt to create an effective labor force made up primarily of Yucatec Maya (see Patch, 1993), while Maya nobles maintained power over the populations under their control (see Roys, 1943; Quezada, 1993: 125-138; Restall, 1997). I suggest that gender and homosexuality were central to power dynamics in the colonial situation. The few major works on homosexuality in colonial Latin America have focused on the building of community, the berdache in indigenous societies, and the use of discourse (see Sigal, 2002). Historians have found that, in colonial Brazil and Mexico, men found other men who wanted to have sex with them. In urban environments these men engaged in a wide variety of sexual activities and even formed their own subcultures with their own rules of engagement (see Gruzinski, 1985; Mott, 1989). The berdache, a crossdressing Native American figure, has intrigued anthropologists for the past century. While most of the scholarship has related to nineteenth-century North America (see Roscoe, 1998), many academics have assumed that the berdache existed in colonial and preconquest Latin American indigenous societies. Indeed, such a cross-dressing figure does appear to have existed, but his meaning is in dispute (see Trexler, 1995; Horswell, 2002). Early modern Europeans engaged in some discussion of homosexuality, and scholars have begun to analyze this discourse. This article expands on this scholarship by attempting to understand indigenous discourse as well.
Leucine aminopeptidase (bovine lens): an electron microscopic study.

The quaternary structure of leucine aminopeptidase was studied by electron microscopy of negatively stained single molecules and of both stained and unstained thin sections of crystals. The predominant images observed in micrographs of single molecules were triangles, many of which had a more dense triangle inset into the outer triangle and rotated by 60° from it. Measurements performed on electron micrographs of thin sections of the crystals cut parallel to the (0001) and (1120) planes gave unit cell parameters of a = 120 A (±10 A) and c = 110 A (±15 A). A quaternary structure composed of six asymmetric bilobal subunits arranged so that the principal lobes are eclipsed and the minor lobes are staggered in a manner similar to that of aspartate carbamoyltransferase is the model that best explains the images observed.
Identifying Islamist Parties Using Gunther and Diamond’s Typology:

Recent democratization in the Muslim-majority countries (MMCs) has led to a surge in interest in the Islamist (or Islamic) parties. Research on these parties has, however, been plagued by the lack ...
Configuration analysis of the electronic excitation in photobiological receptors

According to configuration analysis of the electronic state wave functions of chlorophyll a, peripheral CC(3b,4b) and isocyclic CO groups are not locally excited to any significant extent. This contrasts with the pyrone CC bond of coumarins where a substantial localization of the triplet excitation as well as photoreactions occur. The lowest excited states (1QQ and 3QQ) of chlorophyll a and bacteriochlorophyll a are also similar in correlating their state wave functions, although the ground states of these molecules are substantially different. The 11-CC bond of 11-cis-retinal protonated Schiff's bases shows no tendency for a localized excitation. Thus the primary photoexcitation of rhodopsin does not involve a preferential excitation at the 11-CC bond. The fluorescence characteristics of firefly luciferins have also been analyzed by the configuration analysis method. The most significant result is that the fluorescent states of luciferin and oxyluciferin monoanion possess a strong charge transfer character from hydroxybenzothiazole to thiazoline, in agreement with experimental observations.
A Search for Scintillation in Doped Cubic Lead Fluoride Crystals

An effort was made to introduce scintillation light in lead fluoride crystals by selective doping. It was found that some rare earth ions doped in the lead fluoride crystal may serve as luminescence centers. The photo- and X- luminescence spectra, the decay time constants and the light outputs were measured for these doped samples. The decay time was found to be at a few milliseconds for these rare earth doped lead fluoride samples, which is too long to be useful for the homogeneous hadronic calorimeter detector concept with dual readout for future high energy physics experiments. Work to introduce scintillation in lead fluoride will continue.
UNSTABLE PLASMA OSCILLATIONS IN A MAGNETIC FIELD

>The small amplitude oscillations of a fully ionized quasi-neutral plasma in a uniform time-independent externally produced magnetic field are considered. Motions of the ions and perturbations of the magnetic field are neglected. The distribution function for the electrons is assumed to depart only slightly from the zeroth order distribution. (W.D.M.)
Characterization of Instantaneous Point-Line Motions

This article discusses systematically the characterization of instantaneous point-line motions, and the higher-order relationship between a point-line motion and the associated rigid body motions. The transformation of a point-line between two positions is depicted as a pure translation along the point-line followed by a screw displacement about their common normal and expressed with a unit dual quaternion referred to as the point-line displacement operator. The derivatives of the point-line displacement operator characterize the point-line motion to various orders with a set of characteristic numbers. Such a treatment leads to a consistent expression or unified treatment for the transformation of lines, point-lines, and rigid bodies. The relationships between point-line motions and rigid body motions are addressed in detail up to the third order.Copyright © 2004 by ASME
Hydration Energies and Structures of Alkaline Earth Metal Ions, M2+ (H2O)n, n = 5–7, M = Mg, Ca, Sr, and Ba

The evaporation of water from hydrated alkaline earth metal ions, produced by electrospray ionization, was studied in a Fourier transform mass spectrometer. Zero-pressure-limit dissociation rate constants for loss of a single water molecule from the hydrated divalent metal ions, M2+(H2O)n (M = Mg, Ca, and Sr for n = 5−7, and M = Ba for n = 4−7), are measured as a function of temperature using blackbody infrared radiative dissociation. From these values, zero-pressure-limit Arrhenius parameters are obtained. By modeling the dissociation kinetics using a master equation formalism, threshold dissociation energies (Eo) are determined. These reactions should have a negligible reverse activation barrier; therefore, Eo values should be approximately equal to the binding energy or hydration enthalpy at 0 K. For the hepta- and hexahydrated ions at low temperature, binding energies follow the trend expected on the basis of ionic radii: Mg > Ca > Sr > Ba. For the hexahydrated ions at high temperature, binding energ...
Donepezil markedly potentiates memantine neurotoxicity in the adult rat brain

The NMDA antagonist, memantine (Namenda), and the cholinesterase inhibitor, donepezil (Aricept), are currently being used widely, either individually or in combination, for treatment of Alzheimer's disease (AD). NMDA antagonists have both neuroprotective and neurotoxic properties; the latter is augmented by drugs, such as pilocarpine, that increase cholinergic activity. Whether donepezil, by increasing cholinergic activity, might augment memantine's neurotoxic potential has not been investigated. In the present study, we determined that a dose of memantine (20mg/kg, i.p.), considered to be in the therapeutic (neuroprotective) range for rats, causes a mild neurotoxic reaction in the adult rat brain. Co-administration of memantine (20 or 30 mg/kg) with donepezil (2.5-10mg/kg) markedly potentiated this neurotoxic reaction, causing neuronal injury at lower doses of memantine, and causing the toxic reaction to become disseminated and lethal to neurons throughout many brain regions. These findings raise questions about using this drug combination in AD, especially in the absence of evidence that the combination is beneficial, or that either drug arrests or reverses the disease process.
Emerging from Chapter 11 Bankruptcy: Is It Good News or Bad News for Industry Competitors?

A firm under Chapter 11 bankruptcy protection may emerge from bankruptcy in a more advantageous competitive position within its industry to the detriment of their industry rivals. Using a sample of 264 firms that emerged from Chapter 11 bankruptcy during the period 1999-2006, I find that its industry competitors demonstrate negative postemergence long-term equity returns and deteriorating financial performance. Additional tests indicate that this outcome is less likely due to overall industry distress. Competitors tend to be more adversely affected if they are in more concentrated industries, if they have lower credit quality, when a more efficient firm emerges, and when the duration of bankruptcy is longer. This study suggests a need to reconsider Chapter lis role in promoting competition and allocation of resources given its negative externalities on industry competitors. Chapter 1 1 of the US Bankruptcy Code is designed to save firms that are in temporary financial distress, allowing them to reduce their debt and giving them time and financing to re-emerge as going concerns. Proponents of Chapter 1 1 bankruptcy assert that it is desirable to allow viable firms to survive as more choices enhance competition and benefit consumers. However, the role of Chapter 1 1 bankruptcy in promoting competition and allocation of resources has been under debate. Opponents of Chapter 1 1 bankruptcy hold that Chapter 1 1 reorganization facilitates the rescue of inefficient firms (Hotchkiss, 1995) and that the existing reorganization process resolves the problem of division among stakeholders in a way that suffers from substantial imperfections (Bebchuk, 1988). These studies focus on the impact of Chapter 1 1 bankruptcy on the filing firm and its stakeholders.
Rubbing-induced polar ordering in nylon-11

Sum-frequency vibrational spectroscopy was used to show that mechanical rubbing could induce domains of ferroelectric ordering in films of odd-numbered nylon. In each domain, the dipole groups of NH and CO were aligned perpendicular to the rubbing direction and parallel to the surface.
Whose Story Is It Anyway? Teaching Social Studies and Making Use of Kuwento

In the Filipino language, kuwento means “story,” but the concept itself encapsulates more than its literal meaning. Similar to talk story events in Hawaiian communities (Au & Jordan, 1981), kuwento serves as a tool to communicate everyday experiences within groups, especially among family and community members (Eugenio, 1981). It is an abstraction of history, congealing experience into a chain of events. It is what Bakhtin (1981) would call a unique speech experience—one that is shaped and developed in continuous and constant interaction with others. Kuwento is largely influenced by other people's words and ideas that eventually become incorporated into one's own. Like story and storytelling, kuwento takes many forms and can be used in the classroom during sharing time to construct and activate newer understandings (Cazden, 1994; Michaels, 1981). In the case of paucity in classroom material, the teacher can engage students to learn through her/his own writing (Vascellaro & Genishi, 1994) and her/his own c...
They were Just People: Stories of Rescue in Poland During the Holocaust

In Memory, Identity, Community (Hinchmann and Hinchmann, eds., Albany: SUNY Press, 1997), a group of authors make the important point that oral narratives not only matter in human science but also,...
The somatotrope: an endocrine cell with functional calcium transients

Growth hormone (GH) secretion by the somatotrope is under dual regulation by the hypothalamic peptides, somatostatin (SS) and GH-releasing hormone (GHRH). Cytosolic free calcium concentration and cumulative GH release were measured simultaneously in anterior pituitary cells from adult male rats. This was made possible using a combination of digital imaging video microscopy with the fluorescent calcium indicator Fura-2 and the reverse haemolytic plaque assay (RHPA) to identify the cell type and measure hormone secretion from the cells under study. This technique allows calcium measurements to be made at very short time intervals (less than 150 ms) in single cells. Spontaneous calcium transients were demonstrated in 85% of GH plaque-forming cells. These occurred at a frequency of 2-13 min-1 and had an amplitude of 50-500 nmoll-1. The somatotropes with the largest calcium fluctuations produced the largest plaques; thus, the calcium transients appeared to correlate with hormone release. Since the somatotrope alone shows these fluctuations, the mean intracellular calcium concentration is 238 +/- 18 nmoll-1 in somatotropes and 113 +/- 8 nmoll-1 in non-somatotropes. Upon exposure to SS (1 nmoll-1) intracellular calcium fell from 200-250 nmoll-1 to 50-100 nmoll-1 with an apparent reduction in oscillations. Withdrawal of SS increased the intracellular calcium level. GHRH increased intracellular calcium but 10 nmoll-1 GHRH given simultaneously with 1 nmoll-1 SS reduced intracellular calcium to that level observed during SS alone. Thus, the SS effect on intracellular calcium predominates. The effects of SS can be mimicked by removal of extracellular calcium, or by the addition of CoCl2 (2 nmoll-1) or by verapamil (100 mumoll-1), two agents which block calcium channels. The hormone secretion index (indicated by the area of the plaque formed in RHPA) enables us to demonstrate that GHRH in this system increases GH secretion, and SS inhibits it. In combination, GHRH and SS oppose one another. Spontaneous calcium oscillations are characteristic for normal somatotropes. These oscillations are related to spontaneous hormone secretion and due to influx of calcium through ion channels in the membrane. Intracellular signalling information may be encoded in both frequency and amplitude of calcium oscillations. The actions of GHRH and SS on regulation of GH secretion are proposed to be mediated, at least in part, by regulation of intracellular cytosolic free calcium. This modulation is dependent on extracellular calcium concentrations. We are now investigating the molecular mechanisms involved in this process.
The physiological challenges of the 1952 Copenhagen poliomyelitis epidemic and a renaissance in clinical respiratory physiology

The 1952 Copenhagen poliomyelitis epidemic provided extraordinary challenges in applied physiology. Over 300 patients developed respiratory paralysis within a few weeks, and the ventilator facilities at the infectious disease hospital were completely overwhelmed. The heroic solution was to call upon 200 medical students to provide round-the-clock manual ventilation using a rubber bag attached to a tracheostomy tube. Some patients were ventilated in this way for several weeks. A second challenge was to understand the gas exchange and acid-base status of these patients. At the onset of the epidemic, the only measurement routinely available in the hospital was the carbon dioxide concentration in the blood, and the high values were initially misinterpreted as a mysterious “alkalosis.” However, pH measurements were quickly instituted, the PCO2 was shown to be high, and modern clinical respiratory acid-base physiology was born. Taking a broader view, the problems highlighted by the epidemic underscored the gap between recent advances made by physiologists and their application to the clinical environment. However, the 1950s ushered in a renaissance in clinical respiratory physiology. In 1950 the coverage of respiratory physiology in textbooks was often woefully inadequate, but the decade saw major advances in topics such as mechanics and gas exchange. An important development was the translation of the new knowledge from departments of physiology to the clinical setting. In many respects, this period was therefore the beginning of modern clinical respiratory physiology.
Information Technology and Urban Labor Markets in the United States

The technologies that now dominate the production of goods and services, especially in advanced industrialized countries, have irrevocably changed the dynamics of the demand for and return to labor. Employment in technology-intensive occupations such as computer programming and network technology has increased at double the rate of US non-farm employment overall since the mid-1990s (US Department of Commerce, 2000), and thousands of other jobs in offices, factories and retail establishments demand technological infrastructures unneeded ten years ago. The ability to manipulate information, and to service and maintain the delivery systems by which information travels among users, has become increasingly linked to earning power. This is particularly true in cities. According to Rondinelli et al., the basis of urban economic development is now ‘a technologyand knowledge-based system of production and services’ (1998: 83) and those without the skills to participate in this system are confined to secondary, futureless roles in urban economies. Information technology has had a major impact on the geography of work, the competition among places (Moss, 1987; Brotchie et al., 1995; Massey, 1995; Atkinson, 1998; Graham, this issue), and the characteristics of urban labor markets. This article focuses on the skill dimension of IT’s impact on urban labor markets, exploring the implications of a ‘technology and knowledge-based system of production and services’ for the prospects, not of places, but of the people who work in them. In doing so, it dwells primarily on the US context, where people-oriented policies, particularly education and workforce development, have assumed a newly prominent role in public and academic conversations about urban vitality. In advanced urban economies, scholars and policymakers argue, measures conventionally pursued to attract firms — tax incentives, urban infrastructure, mega-projects focused on drawing tourists or convention-goers — are increasingly less effective, because human capital, not physical capital, has become the twenty-first century’s key competitive advantage (Clarke and Gaile, 1998; Rondinelli et