cssi/SciSciGPT-SciSciNet huggingface dataset:
Solid-state reactive sintering mechanism for proton conducting ceramics

Abstract The recently developed solid-state reactive sintering (SSRS) method significantly simplifies the fabrication process for proton conducting ceramics by combining phase formation, densification, and grain growth into a single high-temperature sintering step. The fabrication simplicity provided by SSRS greatly enhances the potential for deployment of proton conducting ceramics in a number of electrochemical devices. Nevertheless, the mechanisms behind SSRS are still poorly understood. In this report, the SSRS mechanism is clarified through a systematic study of the effect of a suite of metal oxide sintering additives on the phase formation and densification of prototypical proton conducting ceramics BaCe 0.6 Zr 0.3 Y 0.1 O 3 − δ (BCZY63), BaCe 0.8 Y 0.2 O 3 − δ (BCY20), BaZr 0.8 Y 0.2 O 3 − δ (BZY20), and BaZr 0.9 Y 0.1 O 3 − δ (BZY10). Sintering additives with metal ions having a stable oxidation state of + 2 and an ionic radius similar to Zr 4 + (which easily occupy the Zr 4 + site of the BaZrO 3 perovskite structure, resulting in the formation of large amounts of defects) produce the best sinterability. Sintering additives with metal ions having multiple stable oxidation states (2 +, 3 +, 4 + etc.) and ionic radii near to Zr 4 + (which also readily occupy the Zr 4 + sites of BaZrO 3 perovskite structure, but form fewer amounts of defects) can result in partial sintering by the formation of mechanically stable highly-porous microstructures with limited grain sizes. Sintering additives with metal ions having stable oxidation states ≥ 3 + or ionic radii far from Zr 4 + are unlikely to form a solid solution with BaZrO 3 and yield no effect on sintering behavior (virtually identical to the control sample without any additives). These findings provide a useful guide for the selection of sintering additives to engineer optimal microstructures in proton conducting ceramics and may have potential consequences in other ceramic systems as well.
FPGA vs. MPPA for Positron Emission Tomography pulse processing

As FPGAs follow Moore's Law and increase in capacity and complexity, they are becoming more complex to use and are consuming increasing amounts of power. An interesting alternative for reconfigurable computing that is lower power and may be easier to program are Massively Parallel Processor Arrays (MPPAs). In this paper we investigate the Ambric AM2045, a commercial MPPA. To understand the differences between the architecture and computational models of MPPAs and FPGAs, we have implemented two pulse-processing algorithms used in Positron Emission Tomography (PET). The algorithms for event timing and event location were developed for FPGAs and then adapted to MPPAs. In this paper, we present the two implementations and discuss the main differences. Specifically, we show that while the MPPA is easier to program than the FPGA, the lack of a real-time mode, their distributed memory structure, and object based programming model posed challenges for optimized versions of these algorithms.
Protective Influences on the Negative Consequences of Drinking Among Youth

The prevention of underage drinking and related outcomes focuses on strengthening protective factors. Using data from the National Longitudinal Study of Adolescent Health ( N = 3,862), the authors examine the effects of protective factors from three domains of adolescents’ lives (individual, familial, and extrafamilial) on experiencing negative consequences of alcohol use, while controlling for relevant risk factors, among youth who have already started drinking. Results showed that protective factors had relatively little influence on not experiencing negative alcohol-related consequences, regardless of social context. One individual protective factor, strategic decision making, was related to negative drinking outcomes in cross-sectional models. In longitudinal models, maternal attachment reduced the likelihood of experiencing negative outcomes over time. The effects of the risk factors remained strong in all models. Findings suggest “mixed-methods” preventive approaches, attending to risk factors, and ...
Cooperative Conversations: The Effect of Cooperative Learning on Conversational Interaction

An ongoing challenge for educators of deaf and hard-of-hearing students is to find opportunities for students to use their language skills in a functional way, that is, through conversation. This study was initiated to determine whether cooperative learning is a viable means of encouraging mainstreamed hard-of-hearing students to engage in conversational interaction with their hearing peers and teachers. A single-subject design utilizing three mainstreamed hard-of-hearing subjects attending middle school was used to examine this question. Results of the study indicated that cooperative learning positively influenced the conversational turns, initiations, moves, and mean length of turn in these hard-of-hearing subjects.
Exciton band of a one-molecule-per-unit-cell crystal: hexamethylbenzene first singlet☆

Abstract The exciton band structure has been determined experimentally, from quantitative band—band fluorescence and absorption measurements, for the first singlet excited state of the low temperature phase of the hexamethylbenzene crystal. At 2 K, the center for the band is at 35156 cm −1 , its bottom (the κ = 0 state) at 35134 cm −1 and its total extent about 40 cm −1 (i.e. much larger than anticipated earlier). We derive a dispersion relation, based on the trigonal topology of the crystal, with six out-of-plane nearest neighbor pairwise interactions of −3.3 cm −1 and six in-plane ones of −0.4 cm −1 . These parameters, based on the exciton band shape, are inconsistent with a transition-multiple—transition-multipole model, and in particular with an octopole—octopole one, based on the π electrons. π-σ interactions are suggested. The neat crystal data are fully consistent with a complete concentration study on isotopic mixed samples of hexamethylbenzene, at 2 K, by absorption and fluorescence spectra with a 1 cm −1 resolution. The mixed crystal results are also consistent with the energy and spectral moments given by the separated-band model and with the behaviour expected from cluster percolation and exciton percolation.
Itanium 2 processor microarchitecture

The Itanium 2 processor extends the processing power of the Itanium processor family with a capable and balanced microarchitecture. Executing up to six instructions at a time, it provides both performance and binary compatibility for Itanium-based applications and operating systems.
Functional galactosyl receptors on isolated rat hepatocytes are hetero-oligomers

Several lines of indirect evidence have supported the conclusion that rat hepatic asialoglycoprotein (or galactosyl; Gal) receptors are hetero-oligomeric. In the present study more direct evidence was obtained using specific antibodies. The Gal receptor contains three different subunits; RHL 1, RHL 2 and RHL 3. Polyclonal antisera that specifically recognize either RHL 1 or RHL 2/3 subunits (Halberg et al., J. Biol. Chem. 262, 9828, 1987) were tested for their ability to interfere with the specific binding of asialo-orosomucoid to intact rat hepatocytes. The different antisera used all completely inhibited specific ligand binding to the receptor. These results indicate that functional Gal receptors on the cell surface are composed of multiple types of subunits. In addition, no evidence was found to suggest that the two previously described functionally distinct receptor populations in hepatocytes can be explained by these receptor populations containing different RHL subunits. We conclude that all receptors on the cell surface are composed of multiple subunits.
Signalling pathways that control vertebrate haematopoietic stem cell specification

Haematopoietic stem cells (HSCs) are tissue-specific stem cells that replenish all mature blood lineages during the lifetime of an individual. Clinically, HSCs form the foundation of transplantation-based therapies for leukaemias and congenital blood disorders. Researchers have long been interested in understanding the normal signalling mechanisms that specify HSCs in the embryo, in part because recapitulating these requirements in vitro might provide a means to generate immune-compatible HSCs for transplantation. Recent embryological work has demonstrated the existence of previously unknown signalling requirements. Moreover, it is now clear that gene expression in the nearby somite is integrally involved in regulating the transition of the embryonic endothelium to a haemogenic fate. Here, we review current knowledge of the intraembryonic signals required for the specification of HSCs in vertebrates.
Abstract 71: Meningioma: response to retinoids and radiation therapy.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Meningioma represents one third of all primary central nervous system neoplasms. Most meningiomas are effectively addressed by surgical resection. However unresectable, partially resected, recurrent and high grade meningiomas are also typically treated with adjuvant or definitive radiation therapy. Retinoids are a class of compounds structurally related to Vitamin A. Retinoic acid (RA), the active derivative of vitamin A and the first diffusible morphogen in vertebrates, has recently been evaluated for its chemotherapeutic and chemopreventive attributes in solid tumors. Additionally, a novel orally bioavailable synthetic retinoid, fenretinide, has been tested with different pharmacokinetics, side effect profile, and mechanism of action than the classic retinoids, all-trans retinoic acid (ATRA) and 13-cis-retinoic acid (13CRA). In this project, we study the effects of retinoic acid agents alone and in combination with ionizing radiation in meningioma cell lines (IOMM-Lee and CH157MN). We demonstrate that ATRA, 13CRA and fenretinide have similar (increasing) toxicity profiles in both cell lines at doses above 1μM; but below this concentration there are minimal changes on cellular proliferation. Pretreatment of meningioma cell lines with ≤1μM doses of ATRA and 13CRA protected cells from radiation-induced cell death, while pre-treatment with fenretinide had no effect. Using flow cytometric analysis, we demonstrated that RA inhibited radiation-induced G2/M phase accumulation. Western blot result showed that ionizing radiation increased Phospho-Chk1 and -Chk2 levels, and decreased the levels of cdc25c, Phospho-cdc25c (Ser126) and Phospho cdc25c(THr68), Pre-treatment with RTRA reversed each of these effects in a dose- and time-dependent manner. These data suggest a role for the classic RAs in radiation protection through modulation of DNA repair through cell cycle checkpoint pathways. Fenretinide, however, works through a different mechanism, and does not result in radiation protection. These divergent roles suggest that fenretinide may escape the concerns of radiation protection of earlier retinoids making it a promising agent for tumor treatment in the periradiotherapy period. Citation Format: Xuan Ren, Hannah Lo, Robert Vanderwaal, Jerry Jaboin. Meningioma: response to retinoids and radiation therapy. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 71. doi:10.1158/1538-7445.AM2013-71
Changing prevalence, profile, and outcomes of patients with HIV undergoing cardiac surgery in the United States.

Objectives Little is known about the prevalence, risk profile, and outcomes of patients with HIV undergoing cardiac surgery. This study was designed to evaluate clinical outcomes and national trends in this population in the United States. Methods Using data from the Nationwide Inpatient Sample from January 1, 2000, to December 31, 2010, prevalence, risk factors and clinical outcomes after cardiac surgery were quantified for patients with HIV. Cox proportional hazards models were used to evaluate the impact of HIV status on postoperative mortality, and weights used to estimate national trends. Results The prevalence of HIV in cardiac surgery patients doubled from 0.1% to 0.2% ( P P = .016). Operative mortality in patients with HIV decreased from 5.6% to 0.87% ( P P = .436), whereas earlier year of operation (adjusted OR 0.72, 95% CI 0.60-0.87, P P = .01) were independent predictors of operative mortality in patients with HIV. Conclusions In contemporary practice HIV does not appear to be associated with incremental operative mortality, except in patients with clinical disorders related to their HIV status.
Chemical characterization of domestic oral tobacco products: Total nicotine, pH, unprotonated nicotine and tobacco-specific N-nitrosamines

In the United States, moist snuff has been studied more widely than other distinct categories of oral tobacco. In this study, we measured pH, moisture, nicotine (total and unprotonated), and tobacco-specific N-nitrosamines (TSNAs) for other established (twist, loose leaf, plug, and dry snuff without pouch) and emerging oral tobacco products (dry snuff pouch, US-made snus, and dissolvable tobacco). Among the seven product categories, product pH ranged from 4.7 to 7.9, and total nicotine concentration spanned from 3.9 to 40.1 mg/g. The most readily absorbable form of nicotine (unprotonated nicotine) varied more than 350-fold, ranging from 0.01 to 3.7 mg/g. While the highest total nicotine concentrations were observed in twist products, snus and dissolvable tobacco had the highest unprotonated nicotine levels. Among all products, total TSNA concentrations ranged from 313 to 76,500 ng/g with dry snuff having the highest total TSNA concentrations. This study demonstrates the diversity among oral tobacco products and highlights the potential of these products to deliver a wide range of nicotine and carcinogenic TSNAs. Characterizing the chemical content of these products may be helpful in further understanding the risk of marketing these products to oral tobacco users and smokers as an alternative and discrete form of tobacco.
A quantitative analysis of reduplicated and variegated babbling

A number of investigators have made reference to the stages of reduplicated and variegated babbling during the latter half of pre meaningful vocal development. Although these categories of utter an...
Brain Tumor Stem Cells

Cancers are composed of heterogeneous cell populations ranging from highly proliferative immature cells to more differentiated cells of various cell lineages. Recent advances in stem cell research have allowed for the demonstration of the existence of cancer stem cells in acute myeloid leukemia, breast cancer, and, most recently, in brain tumors. Each of these has some similarities with the normal stem cells in the corresponding organs. In brain tumors, putative cancer stem cells have been identified from glioblastoma multiforme, medulloblastoma and ependymoma. These tumor-derived cells self-renew under clonal conditions, and differentiate into neuron- and glia-like cells as well as into abnormal cells with mixed phenotypes. The tumor stem cells, but not the rest of tumor cells form secondary tumors by transplantation into immunodeficient mouse brain. In this review, we discuss the cellular and molecular relationships between brain tumor stem cells and normal neural stem cells, and also the possible clinical implications of brain tumor stem cells.
The determination of the state covariance matrix of moving-average processes without computation

Abstract It is shown that by choosing a suitable state space representation of an MA( q ) process the necessity to compute the initial state covariance matrix does not arise. This result reduces the computational efforts for maximum likelihood estimation via Kalman filtering.
Influence of maternal lead ingestion on caries in rat pups.

Lead is one of the most toxic and pervasive pollutants in society, and although there has been some lowering of blood lead levels in recent years, the levels continue to be of concern for African Americans, central city residents, residents in the Northeast region of the United States, persons with low income, and those with low educational attainment1. Notably, these are the persons and the region where the highest prevalence of dental caries is observed. Information relating lead toxicity to oral health is sparse, but the preponderance of epidemiological data shows a relation between lead in the environment and the prevalence of dental caries2,3. Using our well-defined rat caries model4, we found that pre- and perinatal exposure to lead results in an almost 40% increase in the prevalence of caries and a decrease in stimulated parotid function of nearly 30%. Levels of lead in milk from lead-treated dams were approximately 10 times as high as the corresponding blood lead levels, suggesting that lead is being concentrated by mammary glands. These findings may help in part to explain the comparatively high levels of dental caries observed in the inner cities of the United States where exposure to lead is common. Environmental sources of lead include drinking water, lead-based paint and, to a lesser extent, automobile and industrial emissions. In humans lead is accumulated and stored in bones (half-life of approximately 62 years5), and even maternal exposure to lead decades before pregnancy can subsequently result in exposure of the developing fetus to elevated levels of lead. Moreover, lead concentration in maternal blood has been shown to increase during pregnancy and lactation because of mobilization of stored lead from bone6, and typically, lead is found in milk at a higher concentration than the level found in maternal plasma at the same time point7.
Atomic-scale imaging and electronic structure determination of catalytic sites on Pd/Cu near surface alloys

Water−gas shift chemistry provides a useful method for producing hydrogen from coal; however, fuel cell applications demand that this hydrogen be free of impurities. Due to their unique properties, Pd/Cu alloys represent an import class of materials used for H purification membranes and also serve as the active metals in many heterogeneous catalysts. Little is known about how Pd and Cu interact electronically in these mixed systems and there is debate in the literature over the direction of charge transfer between the two species. This study used the differential conductance (dI/dV) spectroscopy capabilities of a low-temperature scanning tunneling microscope (STM) to investigate the atomic-scale electronic structure of Pd/Cu surface alloys. dI/dV spectroscopy gives a direct measure of the local density of states of surface sites with subnanometer precision. Results from this work demonstrate that individual, isolated Pd atoms in a Cu lattice are almost electronically identical to their host atoms. Over an...
An investigation of the dynamic absorber effect in high-speed machining

Abstract In order to achieve increased material removal rates in high-speed machining, stable cutting conditions may be selected based on the system dynamics. In this paper, we apply Receptance Coupling Substructure Analysis to develop models for a stacked flexure setup and a spindle-holder–tool assembly in order to investigate the ‘dynamic absorber effect’ that can improve the system dynamic stiffness and, therefore, increase the critical stability limit in machining. The dynamic absorber effect results from an interaction between modes associated with the individual substructures, e.g. the spindle-holder and tool in the spindle-holder–tool assembly. Experimental results are provided for: (1) a two degree-of-freedom stacked flexure assembly; and (2) a machining center. These results can be considered in the selection of assembly parameters, such as tool overhang length, as well as in the design of spindle, holder, and tool components in order to improve dynamic stiffness and, consequently, material removal rates.
Flavone mutagenicity in Salmonella typhimurium: dependence on the pKM101 plasmid and excision-repair deficiency

Flavones mutagenic in Salmonella typhimurium fall into two distinct classes, characterized by different structural and metabolic activation requirements and by different strain responses. The mutagenic potencies of a prototype agent of each class, quercetin (3,3′,4′,5,7-hydroxyflavone) and norwogonin (5,7,8-hydroxyflavone), were determined in tester strains differing in excision-repair capability and in the presence or absence of plasmid pKM101. Two series of strains were used, one with the hisD3052 frameshift mutation and one with the hisG46 missense mutation. With both agents and for both series of strains, the mutagenic response was markedly dependent on the absence of excision repair and the presence of the pKM101 plasmid.
Finite Element Based Method to Predict Gas Permeability in Cross-ply Laminates

A finite-element based method is developed to predict gas permeability in cross-ply laminates. Based on Poiseuille's Law and Darcy's Law, the gas permeability is presented in terms of crack densities, microcrack opening displacements and an experimentally determined constant. The crack densities in each ply are predicted using finite element analysis based on energy concept of micro-fracture mechanics. The microcrack opening displacement of the representative volume element in cross-ply laminate is computed using three-dimensional finite element analysis. The normalized gas permeability in three laminates with different lay-ups are predicted and compared using the current model. Finally, a permeability-related material constant is quantified using the experimental results available in the literature.
EEG observations in a case with thalamic syndrome.

Abstract A case of thalamic syndrome of the Dejerine-Roussy type is presented. EEG studies reveal that although bilaterally symmetrical rhythmic activity may be present when the patient is awake, during drowsiness and deeper sleep a marked asymetry often appears, with early disappearance of alpha activity and reduction or abolition of spindles on the side involved. Thalamic integration in the sleep mechanism is briefly discussed.
An N-methyl-D-aspartate receptor mediated large, low-frequency, spontaneous excitatory postsynaptic current in neonatal rat spinal dorsal horn neurons.

Abstract Examples of spontaneous oscillating neural activity contributing to both pathological and physiological states are abundant throughout the CNS. Here we report a spontaneous oscillating intermittent synaptic current located in lamina I of the neonatal rat spinal cord dorsal horn. The spontaneous oscillating intermittent synaptic current is characterized by its large amplitude, slow decay time, and low-frequency. We demonstrate that post-synaptic N-methyl- d -aspartate receptors (NMDARs) mediate the spontaneous oscillating intermittent synaptic current, as it is inhibited by magnesium, bath-applied d-2-amino-5-phosphonovalerate (APV), or intracellular MK-801. The NR2B subunit of the NMDAR appears important to this phenomenon, as the NR2B subunit selective NMDAR antagonist, alpha-(4-hydroxphenyl)-beta-methyl-4-benzyl-1-piperidineethanol tartrate (ifenprodil), also partially inhibited the spontaneous oscillating intermittent synaptic current. Inhibition of spontaneous glutamate release by the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) or the mu-opioid receptor agonist [ d -Ala2, N-Me-Phe4, Gly5] enkephalin-ol (DAMGO) inhibited the spontaneous oscillating intermittent synaptic current frequency. Marked inhibition of spontaneous oscillating intermittent synaptic current frequency by tetrodotoxin (TTX), but not post-synaptic N-(2,6-dimethylphenylcarbamoylmethyl)triethylammonium bromide (QX-314), suggests that the glutamate release important to the spontaneous oscillating intermittent synaptic current is dependent on active neural processes. Conversely, increasing dorsal horn synaptic glutamate release by GABAA or glycine inhibition increased spontaneous oscillating intermittent synaptic current frequency. Moreover, inhibiting glutamate transporters with threo-beta-benzyloxyaspartic acid ( dl -TBOA) increased spontaneous oscillating intermittent synaptic current frequency and decay time. A possible functional role of this spontaneous NMDAR–mediated excitatory postsynaptic current in modulating nociceptive transmission within the spinal cord is discussed.
Functional integrity of ErbB-4/-2 tyrosine kinase receptor complex in the hypothalamus is required for maintaining normal reproduction in young adult female rats.

ErbB-1 tyrosine kinase receptors are necessary for maintaining female reproduction by modulating the release of LH-releasing hormone (LHRH). Changes in ErbB-1 signaling capacity in aging rats are linked to compromised reproduction. The interactive and synergistic nature of different members of ErbB receptors in mediating signal transduction exists in many cellular systems. Particularly, the interactions among ErbB-1 and ErbB-2 or ErbB-4 and ErbB-2 are known to be involved in the stimulation of LHRH secretion during sexual maturation. Thus, ErbB-4/-2 receptors may also play a role in maintaining reproduction during adulthood, and consequently, alteration in ErbB-4/-2 signaling capacity may contribute to compromised reproductive competence during aging. By in situ hybridization histochemistry, ErbB-4/-2 mRNAs were detected in the preoptic area (POA) and arcuate nucleus, which are important areas involved in the control of LHRH neuronal activity. RT-PCR analyses showed that levels of ErbB-4/-2 mRNA increased...
Using possible-selves theory to understand the identity development of new teachers

Abstract Questions about identity and future success often occupy the thinking of individuals during life transitions. Possible-selves theory describes how future-oriented thought provides identity-relevant information and motivation to pursue self-relevant goals. Expected and feared possible selves of beginning teachers (n = 221) were analyzed revealing four main categories (i.e., interpersonal relationships, classroom management, instruction, and professionalism). Differences between student and beginning inservice teachers suggest a transitional trajectory that could have implications for understanding the “how” of teacher identity development. Possible-selves theory may help bring a degree of unity across divergent frameworks and help link identity to broader issues of teacher development.
Measurement of absolute spectral reflectivity from 1. 0 to 15 microns

A device that can be used for the measurement of the absolute spectral reflectivity or reflectance of metals, paints, etc. is described. The unit is used in conjunction with a Perkin-Elmer Model 83 monochromator equipped with an NaCl prism for the wavelength range 1.0 to 15.0 microns. Preliminary results for MgO, polished copper, molybdenum, and electrolytic gold are presented.
A NONPLANAR SOURCE TO PLANAR APERTURE ALGORITHM

A new algorithm for modeling the propagation within a nonplanar source is presented. The algorithm represents the effects of diffraction and attenuation in the propagation of acoustic waves from a nonplanar source to the associated source aperture. The algorithm is a generalization of the linear propagation methods of Christopher and Parker [J. Acous. Soc. Am.90, 507–521 (1991)]. When used to propagate the normal velocity source description to obtain a pressure description of the field, the algorithm is equivalent to the Rayleigh integral model of Williams [J. Acous. Soc, Am.17, 219–227 (1946)] and O'Neil [J. Acous. Soc. Am.21, 516–526 (1949)]. Additionally, in propagating the field beyond the aperture plane the new algorithm allows for specified aperture plane conditions and facilitates the use of very efficient linear and nonlinear beam propagation methods. The algorithm can also be extended to approximate the effects of reflections occurring within the nonplanar source. An efficient implementation of t...
Magnetic resonance imaging and two-dimensional echocardiography. Alternative approach to aortography in diagnosis of aortic dissecting aneurysm

Abstract Unrecognized acute dissection of the aorta requires rapid and accurate diagnosis for appropriate management. The "gold standard" for diagnosis has been invasive angiography, but this diagnosis can be achieved noninvasively via two-dimensional echocardiography, computed tomographic scanning, and magnetic resonance imaging. Two patients are described in whom echocardiography and magnetic resonance imaging were complementary diagnostic aids. The advantages and disadvantages of echocardiography, computed tomographic scanning, magnetic resonance imaging, and aortography in aortic dissection are discussed. It is anticipated that a combination of noninvasive diagnostic aids will eliminate the need for invasive angiography in many instances in the future.
Recent Developments in Products Liability in the United States

For somebody interested in comparative law to report on recent developments in products liability in the United States as part of a discussion on a wider scale is, in a way, a pleasant challenge. Whatever the theoretical arguments concerning the possibility of legal transplants' are, there can be little doubt that American products liability law has had a significant influence on its counterpart in Europe, as German scholars active in this field have recognized.2 Indeed, in the famous "Chickenpest" case, the German Bundesgericht used the expression strict liability in English in its opinion.3 It is thus interesting to see whether newer developments have narrowed or widened the gap between American products liability law and that of Europe or Canada. But to summarize recent developments in an area which has seen such massive growth and received such detailed treatment by specialized scholars may be a little presumptuous if attempted by somebody who is not an expert in the field.4 No more will thus be attempted here than to give, by way of background for the other contributions on products liability, a very brief survey of the history of the field, followed by a discussion of currently unresolved legal issues, of the practical impact of products lia-
Matching pulmonary structure and perfusion via combined dynamic multislice CT and thin-slice high-resolution CT.

Abstract Taking advantage of two scan modes of an electron beam CT scanner (Imatron), we have developed a method utilizing x-ray CT for relating pulmonary perfusion to global and regional anatomy. A high temporal resolution mode, used to follow bolus contrast agent, is combined with a high spatial resolution mode to obtain the structure-function fusion. A software module has been developed for our image analysis package (VIDA) ® to automatically calculate physiologic parameters of flow and integrate these color coded functional measurements into a corresponding high spatial resolution data set. We present the scanning methodology details and give examples from our physiologic based research to demonstrate strengths of combining dynamic and high resolution CT to uniquely characterize pulmonary normal and pathophysiology.
Methionine Sulfoximine-Resistant Mutants of Tobacco

Selecting mutants from populations of haploid plant cells cultured in vitro may provide a rapid method for recovering agriculturally useful variants. Mutants of Nicotiana tabacum were recovered which were resistant to methionine sulfoximine, an analog structurally similar to methionine. Induction of chlorosis was prevented or less evident in mutant plants that were inoculated withPseudomonas tabaci, a bacterial pathogen which produces a toxin that is a structural analog of methioning. Several mutants show a specific increase in the level of free methionine.
Effects of cultural-context, gender, and acculturation on perceptions of work versus social/leisure time usage

Abstract Findings of an empirical study support the hypotheses that time usage patterns for work versus social/leisure activities differ across individuals originating from low-context cultures of Western Europe and individuals originating from high-context cultures of Asia, Japan, the Middle East, and South America. Perceptions of work time were higher (i.e., more work hours per day) in high-context cultures and perceptions of social/leisure time were higher (i.e., more social/leisure hours per day) in low-context cultures. Such effects of cultural-context were more dominant for men than for women. The findings further indicate that these differences get narrowed with high acculturation in U.S. culture. The theoretical rationale for these hypotheses is developed by integrating concepts of time activity, time priority, and time setting in a summary conceptual model. Implications of results for marketing to subcultural as well as cross-cultural groups are discussed with particular reference to the high-context cultures of developing countries that tend to handle time in a polychronic manner compared to low-context cultures of developed countries (with the exception of Japan) that handle time in a monochronic manner.
Development of electronic device simulations for educational purposes

A comprehensive set of semiconductor device simulation tools, written in Java, is being developed for instructional use. These interactive programs can be launched from an electronic textbook or from lecture presentation material. At present these tools demonstrate introductory quantum mechanics, several aspects of semiconductor physics, and both zero-current and drift-diffusion device simulations in one dimension. Development of two-dimensional simulations is in progress.
MS Xα calculations on the chlorofluoromethanes

Abstract MS Xα calculations have been performed on the chlorofluoromethanes (CF4, CF3Cl, CF2Cl2, CFCl3, CCl4) to assess the applicability of this method for such mixed halomethanes. The agreement of the ionization potentials calculated from transition state energies with the experimentally measured photoelectron spectral ionization potentials was extremely good. The transition state procedure was also used to estimate the electron affinities of the chlorofluoromethanes. The results indicated that the electron affinities for CF4 and CF3Cl would be negative, those for CFCl3 and CCl4 should be possitive and that for CF2Cl2, while the calculations show it to be positive, the positive value was within the demonstrated inherent computational error of the calculational procedure.
In vitro ruminal fiber digestion as influenced by phenolic-carbohydrate complexes released from sorghum cell walls

Abstract Objectives were to isolate groups of phenolic-carbohydrate complexes from brown-midrib 6 and normal ‘Redlan’ sorghum ( Sorghum bicolor (L.) Moench) and to investigate the influence of isolated complexes on in vitro fiber digestion. Three field replicates of brown-midrib 6 and normal sorghum stem were harvested 1 week after physiological maturity of grain. Extracts of cellulase-digested neutral detergent fiber (NDF) of both sorghums inhibited in vitro dry matter digestion when added to in vitro ruminal incubations at quantities equivalent to 0.5, 1.0, and 2.0 g sorghum stem NDF. Cellulase extracts separated by size exclusion Chromatograph y (Sepharose CL-6B) yielded two major peaks that absorbed at 320 nm. Phenolic-carbohydrate complexes isolated in Peak 2 were lower in p -coumaric (PCA): ferulic acid (FA) ratios and higher in xylose: arabinose ratios than complexes isolated in Peak 1. When concentrated solutions of isolated fractions were added to in vitro ruminal incubations of sorghum leaf blade (0.25 g) at quantities equivalent to 0.5, 1.0, 2.0, and 3.0 g of sorghum stem NDF, in vitro NDF digestibility of sorghum leaf blade was reduced more by addition of Peak 2 than Peak 1 for both sorghums, but the effect on digestibility was greater for brown-midrib 6 . The pH of resulting solutions did not influence in vitro dry matter digestibility. Further separation of Peak 2 by size exclusion chromatography (Sephadex LH-20, for separation of compounds with lower molecular weights) yielded several major peaks that absorbed at 320 nm. One of these peaks, with a low molar p -coumaric: ferulic acid ratio, inhibited fiber digestion when added at quantities equivalent to 5.0 g of sorghum stem NDF. Results suggest that phenolic-carbohydrate complexes low in PCA: FA molar ratio acid and high in xylose: arabinose ratio may inhibit ruminal fiber digestion, although the mode of action is not yet clear.
Plasma membrane nanoporation as a possible mechanism behind infrared excitation of cells.

Objective. Short infrared (IR) laser pulses have been used to stimulate action potentials in neurons both in vivo and in vitro. However, the mechanism(s) underlying this phenomenon has remained elusive. In vitro studies have found that pulsed IR exposure generates a nearly instant change in capacitance in the plasma membrane, characterized by inward rectification, a common feature in pore-forming exposures, such as electrical pulses and acoustic shock waves. Based on this similarity, we hypothesize that the mechanism of IR stimulation is the formation of short-lived nanopores in the plasma membrane. These transient, small-diameter pores allow the influx of extracellular ions that lead to action potential generation, possibly through activation of secondary messenger pathways or depolarization of the cell membrane resulting in activation of voltage-gated ion channels. Approach. A variety of fluorescent markers are used to observe the cell response to IR stimulation to monitor for effects indicative of nanoporation in other modalities. Main results. We observe rapid, transient rises in intracellular Ca2+, influx of YO-PRO-1 and propidium iodide into the cell signifying membrane permeabilization, cellular blebbing and swelling, and activation of the intracellular phosphoinositides lipid signaling pathway. Significance. This conclusion better explains the experimental observations and limitations of IR-induced neurological stimulation and represents a distinct theoretical shift in the understanding of the mechanism of IR-induced stimulation.
A survey of IRAS data on 41 classical novae

The IRAS database has been searched for detections of 41 classical novae using coadditions of survey scans; 15 were detected. IRAS temporal observations of novae in outburst are discussed. The observed long-wavelength infrared distributions of DQ Her, and possibly HR Del, can be explained by emission from small (a of about 0.1 microns) dust grains heated by the central object. An alternative explanation for the energy distributions of DQ Her and HR Del is emission from fine-structure lines. FH Ser and LW Ser display energy distributions that have color temperatures much too hot to be due to heating of dust by the central source in any plausible scenario. Line emission is probably the best explanation of their observed energy distributions. The novae NQ Vul and LV Vul have energy distributions that may be contaminated by emission from galactic cirrus. The unusual object PL 1547.3-5612 exhibits an energy distribution that does not resemble those of planetary nebulae or other novae detected in this sample. An IRAS low-resolution spectrum of RR Tel shows the 10-micron silicate emission feature.
Biophysical characterization of the free IκBα ankyrin repeat domain in solution

The crystal structure of IκBα in complex with the transcription factor, nuclear factor κ-B (NF-κB) shows six ankyrin repeats, which are all ordered. Electron density was not observed for most of the residues within the PEST sequence, although it is required for high-affinity binding. To characterize the folded state of IκBα (67–317) when it is not in complex with NF-κB, we have carried out circular dichroism (CD) spectroscopy, 8-anilino-1-napthalenesulphonic acid (ANS) binding, differential scanning calorimetry, and amide hydrogen/deuterium exchange experiments. The CD spectrum shows the presence of helical structure, consistent with other ankyrin repeat proteins. The large amount of ANS-binding and amide exchange suggest that the protein may have molten globule character. The amide exchange experiments show that the third ankyrin repeat is the most compact, the second and fourth repeats are somewhat less compact, and the first and sixth repeats are solvent exposed. The PEST extension is also highly solvent accessible. Iκ Bα unfolds with a Tm of 42°C, and forms a soluble aggregate that sequesters helical and variable loop parts of the first, fourth, and sixth repeats and the PEST extension. The second and third repeats, which conform most closely to a consensus for stable ankyrin repeats, appear to remain outside of the aggregate. The ramifications of these observations for the biological function of IκBα are discussed.
Picosecond dynamics of low-density excitons in GaAs quantum wells

Time-resolved photoluminescence (PL) measurements were performed on a multiple GaAs/AlGaAs quantum well structure. The rise and decay profiles of PL centered at the free exciton line and the impurity related excitonic-complex line were investigated as a function of temperature at a low excitation density (approximately 10 9 cm -2 ). This study provides new information on how excitons are captured by impurities and on the kinetics of excitonic-complex formation and annihilation. The exciton capture time by impurities is about 250 ps and independent of temperature (less than 80 K) when the exciton density is comparable to the residual impurity density.
Effects of atrial natriuretic peptide in clinical acute renal failure.

Fifty-three consenting patients meeting clinical and urine composition criteria for established intrinsic ARF were assigned to two treatment groups. Group I patients were treated with human atrial natriuretic peptide (ANP) with or without diuretics. Groups II patients were treated with or without diuretics and with no ANP. Age, sex, etiology of ARF, entry serum creatinines (SCr) (Group I, 5.3 +/- 1.8; Group II, 5.1 +/- 2.1 mg/dl) and creatinine clearances (CCr) (Group I, 9.9 +/- 2.1; Group II, 9.2 +/- 2.1 ml/min) were similar. Thirty patients received ANP [0.20 micrograms/kg/min i.v. x 24 hr (N = 20) or 0.08 micrograms/kg/min i.a. x 8 hr (N = 10)] and furosemide, 0.5 mg/kg/hr x 24 hr or mannitol, 12.5 g every six hours x 4, or no diuretic; 23 Group II patients received diuretics as above or no diuretic in a similar distribution to Group I. CCr (verified with simultaneous inulin clearances x 12, r = 0.93, P < 0.001) increased significantly by eight hours of ANP treatment to 17.1 +/- 3.2 ml/min and by 24 hours after discontinuing ANP to 21.0 +/- 4.4 ml/min (both P < 0.05). There was no corresponding increase in CCr in Group II. Dialysis was required in 23% of Group I and in 52% of Group II patients (different at P < 0.05). Mortality rates of 17% for Group I and 35% for Group II were not significantly different (P = 0.11). It is concluded that parenteral ANP increases CCr and reduces need for dialysis in patients with established intrinsic ARF.
Books and the popularization of science

This article discusses best-selling science books, the characteristics of the audience for popular science books, and the role of books within science popularization and science education. Best-selling science books have been rare, but generally readable. Regional books, also important sources of scientific information, aim at much smaller, far more price-sensitive audiences. Many successful regional, nontechnical science books are readable, heavily illustrated, and in some cases, cross-disciplinary. To increase the attentive audience for scientific information, improvement in science education is necessary, and the most efficacious role for scientific institutions may be the production of materials that can be easily incorporated into school curricula.
Synthesis and characterization of 1-methyl-1-silaindane and 1-methyl-1-germaindane

Abstract New synthetic routes to 1-methyl-1-silaindane (1b) and 1-methyl-1-germaindane (1b) were developed and the desired products were obtained in good isolated yield. Compounds 1a and 1b were fully characterized by mass spectroscopy, 1H and 13C{1H} NMR, and infrared spectroscopy.
The isolation and structure of 23-deoxyantheridiol and the synthesis of its C-22 epimer☆

Abstract The isolation and identification of a new steroid, 22 R -3β, 22-dihydroxy-24-carboxymethylenecholest-5-en-7-one 24″, 22-lactone ( 1 ) (23-deoxyantheridiol) from the culture filtrates of the water mold Achyla bisexualis is described. A synthesis of the 22 S -isomer of ( 1 ) is also reported. On the basis of these studies the 22 S , 23 R -stereochemistry is proposed for the fungal sex hormone antheridiol.
Gas chromatographic equivalent chain lengths of fatty acid methyl esters on a silar 10C glass capillary column

Gas chromatographic equivalent chain lengths have been determined for a number of fatty acid methyl ester isomers on a Silar 10C glass capillary column at 170 C. The results are comparable with others published for polycyanopropylsiloxane columns.
Invertebrate neuropeptides resembling vasotocin and some analogues: synthesis and pharmacological properties.

The solid phase synthesis of three invertebrate vasopressin-oxytocin homologs: AVP-like factor, F11, ([Leu2, Thr4] AVT)2 isolated from subesophageal and thoracic ganglia ofLocusta migratoria3, Arg-conopressin-S4. ([Ile2, Arg4] AVT), Lys-conopressin-G4 ([Phe2, Arg4] LVT), both isolated from the venom of fish-hunting marine snails of the genusConus and six of their analogues is reported. These analogues are: [Arg4] AVT, [Ile2] AVT, [Leu2] AVT, [Phe2, Arg4] AVT, [Arg4] LVT and [Ile2, Arg4] LVT. All peptides were tested for antidiuretic and vasopressor activities.
Failure of sodium benzoate to alleviate plasma and liver ammonia in rats.

The intraperitoneal administration of l-norvaline and l-methionine-SR-sulfoximine to rats caused an increase in the concentration of ammonia in plasma as well as in liver. These compounds interfere with urea and glutamine formation, respectively. Subsequent injection of sodium benzoate failed to alleviate ammonia levels, and on the contrary, caused a further increase. Sodium benzoate itself, when administered, resulted in higher levels of ammonia in plasma and liver of the rats. Administration of glycine to rats treated with benzoate did not lower ammonia levels indicating that other factors besides glycine may also be necessary for the removal of sodium benzoate.