cssi/SciSciGPT-SciSciNet huggingface dataset:
Using Nanoparticles to Control Cellular Membrane Potential

All cells generate an electrical potential (Vm) across their plasma membrane driven by a concentration gradient of charged ions. A typical resting membrane potential ranges from −40 to −70 mV, with a net negative charge on the cytosolic side of the membrane. Disruption of this electrochemical equilibrium causes Vm to become more positive or more negative relative to its resting state, referred to as “depolarization” or “hyperpolarization,” respectively. Changes in membrane potential have proven to be pivotal not only in normal cell cycle progression, but also in malignant transformation. Using polystyrene nanoparticles as a model system, we use a combination of fluorescence microscopy and flow cytometry to measure changes in membrane potential in response to nanoparticle binding to the plasma membrane. We find that cationic nanoparticles depolarize both CHO-K1 and HeLa cells. The cellular binding of anionic nanoparticles does not lead to a discernible trend in altered membrane potential. Maintenance of the resting membrane potential depends on the presence of two-pore-domain potassium “leak” channels, which allow for outward diffusion of potassium ions along their concentration gradient. Using an assay that tests the diffusion of ions through these potassium channels, we observe reduced permeability of the channels when cells are treated with nanoparticles. Based on a dynamical system model of the cell, we conclude that this loss of permeability likely results from physical blockage of the channel itself by the particle. Prevention of potassium ion efflux due to blocked channels causes accumulation of positive charge inside the cell, resulting in a depolarized membrane. By understanding the ways in which nanoparticles can be utilized to selectively generate cellular responses, we can begin to consider them as active species that may alter the very systems they are currently designed to probe.
Informal corporate entrepreneurship: implications from the failure of the Concorde alloy foundry and the success of the Toshiba laptop

The results to date of formal corporate entrepreneurship, as exemplified by Internal New Venture Divisions and Corporate Venture Capital have been mixed. In contrast, frustrated internal entrepreneurs have tried informal approaches to circumvent the company bureaucracy and obtained exceptional results. In this study, we discuss two cases: the Concorde alloy foundry; and the Toshiba laptop computer, which were both initially successful. The Concorde alloy project was approved and strongly supported by the company President, but was discontinued after 26 years. Instead, the Toshiba laptop project was vetoed twice by the headquarters and driven underground. After it surfaced by chance in Europe, the laptop became almost overnight a spectacular success, which resulted into a multi-billion dollar business and worldwide leadership of Toshiba in subnotebooks. By comparing the histories of the two projects, we analyse the key success factors for informal corporate entrepreneurship and explain why the first approved and supported project failed and why the second unapproved and ostracised project succeeded. We conclude with lessons learned and implications for R&D project managers and corporate entrepreneurs, the roles of champions for protecting the informal innovators, and how to recognise informal corporate entrepreneurs with high potential for success.
Phenylhydrazine-induced anemia in chinook salmon

Abstract Single injections of phenylhydrazine (12.5 μg/g body weight) produced severe hemolytic anemia in chinook salmon (Oncorhynchus tshawytscha). Within 10 days erythrocyte counts, hemoglobin concentrations, and hematocrits were reduced to 1–5% of normal. Microscopic examination revealed pronounced swelling and rupture of erythrocyte nuclei and degenerated erythrocytes in blood vessels of all organs studied. Histologic changes were noted in the kidney, liver and spleen. Blood components returned to near normal levels 95 days after injection.
The Student Gifted in Mathematics and Science

Much more needs to be done for the nation's tal ented students in mathematics and science than is now happening in the schools, asserts this writer, who describes in this article the Study of Mathe matically Precocious Youth (SYMPY) at The Johns Hopkins University and what has been accomplished for the young participants.
Shear-induced structure formation in solutions of drag reducing polymers

Abstract The phenomenon of shear-induced structure formation has been investigated for several drag reducing polymers. Aqueous solutions of high molecular weight partially hydrolyzed polyacrylamide, polyacrylamide, and poly(ethylene oxide) have been examined in the concentration range of 100–4000 ppm by weight. Experimental protocols included rheological and rheo-optical characterization under simple shear flow, and molecular weight analysis by chromatography following various shear histories. All solutions exhibited time-dependent stresses and turbidity patterns under high shear, indicative of structure formation. Two regimes of behavior were found with the partially hydrolyzed polyacrylamide. At concentrations below 1500 ppm, aggregate formation occurred above a critical shear rate on time scales of minutes that relaxed back over similar time scales to an apparent homogenous state on cessation of flow. However, these sheared solutions developed irreversible, large-scale turbidity and eventual precipitation on quiescent storage over several days. At higher concentrations, phase-separated droplets formed under shear that also showed ripening of the turbidity and eventual precipitation upon quiescent storage for days. The kinetics of the semi-reversible aggregate formation and relaxation processes in the lower concentration regime showed a regular variation with shear rate and concentration. The strength of the structure formation and precipitation processes was lessened in the presence of salts. Similar behavior patterns were exhibited by the other systems, however, the strength of the structure formation was also somewhat lessened compared to the partially hydrolyzed polyacrylamide. Correlations with solutions being used in ongoing turbulent drag reduction studies suggest that such structure formation may play an important role in the drag reduction process.
On the oligomerization mechanism of Brønsted acid-catalyzed conversion of furans to diesel-range fuels

Abstract The conversion of biomass to fuels and chemicals is considered to be a promising alternative to petroleum-based conventional routes. The oligomerization of biomass-derived furans can yield an important precursor toward diesel fuel; yet, the underlying mechanism is not well understood. This study investigates the furan oligomerization mechanism and kinetics via density functional theory and microkinetic modeling. The oligomerization proceeds in the presence of water and a Bronsted acid and requires an aldehyde and two furan molecules, each with at least one unprotected α-C. If only furans are present in the acidic, aqueous environment, the initial hydrolysis to produce the aldehyde limits the oligomerization rate. Two strategies to accelerate the oligomerization are proposed: furnishing the furans with electron-donating substituents or supplying a non-self-condensing aldehyde in the reaction mixture.
Entrepreneurial Selection, Financial Markets, and Patterns of International Trade

This paper introduces entrepreneurial selection and imperfect financial markets to the 2x2x2 model of international trade. Entrepreneurs are heterogeneous in ability and borrow from banks who do not observe their ability. The pattern of international trade depends on (1) factor abundance, (2) endogenously determined productivity, and (3) endogenously determined financial market imperfections. We show that entrepreneurial selection results in a diminished Rybczynski effect and financial market imperfections further reduce the effect; hence differences in capital abundance imply a smaller trade volume than predicted by the Heckscher-Ohlin theorem. The results help to resolve a conflict between the Heckscher-Ohlin model and data. [F11]
Fragment mass-angle correlation in U238 + n fission

Abstract The U238(n,f) process has been investigated between 1.2 and 1.7 MeV neutron energy. A photographic emulsion technique was used to identify individual fragments and their angular distribution for different range-ratio groups. The fraction of total fissions in each group was found to be independent of neutron energy. The angular distributions of all groups agree with previous measurements without mass discrimination except for the most nearly equal-fragment group. The data suggest that this group has a larger but less enegy-dependent anisotropy than other groups.
SPEED DMON

This paper presents a low-overhead, high-performance cache coherence protocol and an interconnect architecture designed to exploit high-bandwidth point-to-point and broadcast features of an optical multichannel interconnect.SPEED DMONintegrates the virtues of snoopy-based schemes and directory-based schemes into a robust hybrid architecture. Directory-assist is used exclusively for decoupled read traffic to eliminate unnecessary broadcasts, while snoopy-assist is used exclusively for write and synchronization traffic to reduce directory overhead and synchronization complexities. The proposed scheme has the potential to reduce network latency by up to 85% as a result of its global independence between read and write operations, full concurrency in channel access, reduced link contention, and efficient broadcast of coherence and synchronization events.
Compensation for light loss due to filtering by macular pigment: relation to hue cancellation.

Background: A long-standing question in colour vision research is how the visual system is able to correct for the significant absorbance of short wave light by the crystalline lens and macular pigment (MP). Such compensation must be required in order to maintain colour constancy across the retina where MP levels are changing quickly and dramatically. Objective: We studied this compensation mechanism by measuring MP spatial density profiles and hue cancellation functions across the central retina in a sample of six young healthy subjects. Method: Yellow (Y, 575 nm)/blue (B, 440 nm) and red (R, 600 nm)/green (G, 501 nm) cancellation functions were obtained at 0, 1, 1.75, 3 and 7° eccentricity. The MP optical density at 460 nm was measured at these same eccentricities using heterochromatic flicker photometry. One subject was assessed repeatedly over a 4-month period during daily supplementation with 30 mg of lutein (L). Results: Hue cancellation values for the Y/B system did not change across the retina (r = 0.09). In contrast, R/G sensitivity changed as a direct function of MP absorbance (r = 0.99). The Y/B values did not change in the one subject supplemented with 30 mg L daily, despite increases in MP of about 50% over 4 months. Conclusions: Despite large variations in MP across the retina, hue cancellation values for the Y-B system across the central retina were constant. For example, one subject's MP density declined from a central peak of 0.99 to near zero at 7° (near 90% transmission difference) yet thresholds for the Y/B system were unaffected. In contrast, the G lobe of the R/G system was directly correlated with MP density. Taken together, these results confirm that the Y/B system compensates for MP density, but the R/G system does not.
An approach to design interface topologies across interdependent urban infrastructure systems

This paper proposes an approach to design or retrofit interface topologies to minimize cascading failures across urban infrastructure systems. Four types of interface design strategies are formulated based on maximum network component degree, maximum component betweenness, minimum Euclidean distance across components and component reliability rankings. To compute and compare strategy effectiveness under multiple hazard types, this paper introduces a global annual cascading failure effect (GACFE) metric as well as a GACFE-based cost improvement (GACI) metric. The GACI metric quantifies the improvement of the strategy effectiveness per kilometer increment of interdependent link length (ILL) relative to a reference strategy with minimum ILL. Taking as examples the power and gas transmission systems in Harris County, Texas, USA, optimum interface designs under random and hurricane hazards are discussed. Findings include that the strategy based on reliability rankings minimizes the GACFE metric, and decreases the GACI value relative to a reference practical strategy by 10–15% under different power grid safety margins. Such metrics will contribute to coupled utility system design or retrofit given that current guidelines or recommended practices in the utility industry mostly rely on minimum Euclidean distances and are yet to include interdependent effects in their provisions.
Evaluation of a hospital-wide resuscitation team: does it increase survival for in-hospital cardiopulmonary arrest?

Abstract Objective: To assess the impact (defined not only with regard to patient outcome but also to record keeping for evaluation of care) of a formal, structured resuscitation team for in-hospital cardiopulmonary resuscitation over the year following its creation. Methods: This is a "before and after" study in which charts of all patients needing resuscitation during the two-year period were reviewed and data arranged in the Utstein Style of in-hospital reporting of cardiac arrests. The review was limited to adults (⩾18 years of age) in nonICU settings. Results: A total of 220 events were identified. Demographics and presenting rhythms for the two periods under review were similar. For the period of August 1996–August 1997 (group 1), there were 70 resuscitation events recorded with a return of spontaneous circulation (ROSC) rate of 21/70 (30%). For the period of August 1997–August 1998 (group 2), 150 events were recorded and the ROSC rate was significantly higher 87/150 (58%)) ( P =0.0002). ROSC after ventricular fibrillation and ventricular tachycardia was similar in both groups (50 vs 57%) ( P =1.00) but an improvement in survival was seen in group 2 from events of bradycardia/perfusing rhythm (25% vs 84%) ( P =0.0003). Survival from PEA/Asystole was also improved during period 2 (18 vs 48%) ( P =0.013). Survival to discharge was seen in 3/50 (6%) of patients in period 1 and 18/102 (18%) of patients in period 2 ( P =0.09). Conclusions: The formation of a structured, formalized hospital resuscitation team was associated with an increase in the number of recorded events, in the number of patients experiencing ROSC and in the percentage of patients who were discharged from the hospital. Facilities with no formal resuscitation team or with no skilled, practiced resuscitator on their current team should consider implementation of a similar strategy.
The soft heap: an approximate priority queue with optimal error rate

A simple variant of a priority queue, called a soft heap, is introduced. The data structure supports the usual operations: insert, delete, meld, and findmin. Its novelty is to beat the logarithmic bound on the complexity of a heap in a comparison-based model. To break this information-theoretic barrier, the entropy of the data structure is reduced by artifically raising the values of certain keys. Given any mixed sequence of n operations, a soft heap with error rate e (for any 0
Reconsidering the Social Location of the Medical Model: An Examination of Disability in Parenting Literature

This paper challenges the view that there is one medical model of disability monolithically and oppressively imposed on disabled people. Because the presence of disability may be ambiguous in any given case, multiple actors, lay and professional, may invoke particular medical models of disability and advance competing claims about an individual’s disabilities and related needs. The literature for parents of disabled children is seen as a resource on which parents can draw in making claims about their children’s disabilities and disability-related needs. Particular attention is given to the assumptions that this literature makes about the identity, resources and dispositions of the audience. Ultimately, these assumptions favor disability claims made by white, highly educated, upper-income parents.
Surgery for ventricular tachycardia unresponsive to medical treatment.

Surgery is indicated in patients with ventricular tachycardia refractory to medical management, provided, a correctable cardiac lesion is present Published data, as well as our own experience, would indicate that surgery in myocardial disease associated with tachyarrhythmia may terminate the disturbances of rhythm with no further need for medication. Direct myocardial revascularization with preinfarction angina, or revascularization early in the course of myocardial infarction, or resection of an older lesion may be the procedure of choice for secondary ventricular tachycardia unresponsive to conservative measures. The operative findings and procedures, and the immediate and late postoperative results in 11 patients operated on for intractable ventricular tachycardia are given. Surgery was performed with the hope that improved cardiac function would terminate dysrhythmia and improve the function of the myocardium.
Detection of prolactin inhibitory activity in uterine epithelial cell secretions and rat serum.

We have shown that the uterus of the rat contains a substance that diminishes the release of the luteotropic hormone PRL by acting directly at the anterior pituitary gland. This study was designed to determine which cell type(s) within the uterus secretes this PRL inhibitory activity (PIA) and if PIA of uterine origin appears in circulation. Enzymatically dispersed cells from uteri of ovariectomized (OVX) rats were cultured for 24 h in serum-free Dulbecco's Modified Eagle's Medium. Estimation of PIA in the spent media from heterogeneous uterine cell cultures was evaluated after 24 h by the ability to suppress PRL release from confluent monolayers of cultured pituitary cells. Spent media from uterine cell cultures containing 0.125 × 106 or 0.25 × 106 cells/well failed to significantly suppress PRL secretion. However, media from 0.5 × 106 and 1 × 106 uterine cells/well induced 36% and 85% inhibition of PRL release, respectively, without affecting basal LH release. To determine which cell type(s) in the uter...
The Permeability of Epidermis Lacking Normal Membrane-Coating Granules: An Ultrastructural Tracer Study of Kyrle-Flegel Disease

Skin lesions from patients with Flegel's disease have been reported to be without membrane-coating granules (Odland bodies). Biopsies of the hyperkeratinized papules of Kyrle-Flegel disease were incubated in vitro with the intercellular tracer, horseradish peroxidase, and the extent of penetration of this substance examined in the light and electron microscopes. The peroxidase was present throughout the corium and extended through the intercellular spaces of the epidermis to a level close to the junction of the granular and keratinized layers; it did not enter the bulk of the thickened stratum corneum of the lesion. Ultrastructural examination revealed the presence of small vesicles in the granular layer, similar in size and shape to membrane-coating granules but lacking a lamellate internal structure; these were occasionally seen fusing with the plasma membrane of the cells. It is suggested that the intercellular permeability barrier to horseradish peroxidase demonstrated in the Kyrle-Flegel lesion may arise from material contributed by these granules to the intercellular space.
Lineage Genera Classification of Lower Paleogene Planktonic Foraminifera: ABSTRACT

Current classifications of planktonic Foraminifera rely on rigid structural hierarchies, defining genera as narrow morphologic entities, commonly with long and discontinuous ranges. Such classifications do not satisfy the criteria of either monophyly or practicality. More properly, genera are based on phyletic successions of species through time, thus creating natural (Linnaean), monophyletic, and stratigraphically restricted taxa. Lower Paleocene species are here reclassified into five lineage-genera. These genera partly overlap in gross morphology and in certain iteratively developed analogous structures, but possess adequate diagnostic features (especially wall texture) for recognition. All presently recognized Paleocene lineages except the chilogumbelinids (including Globoconusa) are derived from the early Danian species "Globorotalia" pseudobulloides, and become sufficiently divergent for generic distinction by late Danian time. This species is derived from, and congeneric with, "Hedbergella" monmouthensis. Globanomalina includes smooth-walled, compressed, globorotaloid forms with slit-like extraumbilical apertures; finely perforate peripheral rims (keels) occur in two species. Morphotypes transitional with the Eocene planispiral genus Pseudohastigerina occur in the uppermost Paleocene and are best interpreted to be part of the reaction range of Globanomalina chapmani. Subbotina includes globigerinid forms with pitted, coarsely perforate (reticulate) walls; late middle Eocene populations gave rise to the predominantly Neogene genera Globorotaloides and Catapsydrax. An innovation critical for phylogeny was the development of coarsely hispid wall surfaces, which first appeared in neanic chambers of the early Danian form, "Globorotalia" pseudobulloides praecursoria. Intensification and persistence into adult chambers of hispid ornamentation accompanied the transition of "G." pseudobulloides praecursoria to "Globorotalia" inconstans in middle Danian time. "G." inconstans is the phyletic base for two isochronous radiations characterized by densely hispid wall surfaces. Acarinina includes globigerinid forms with rounded chambers and umbilical to extraumbilical primary apertures. Dorsal sutural apertures appear in two middle Eocene species (Truncorotaloides of authors); these forms, however, are phyletic "dead-ends" and are not here afforded generic recognition. Morozovella includes globorotaloid forms with conicotruncate chambers and peripheral concentrations of somewhat elongate rugosities (keels). Both radiations diverge into several disparate lineages. Poorly understood problems of intense parallelism and isomorphism preclude for the present more refined delineation of phylogenies. End_of_Article - Last_Page 465------------
The energy efficiency of carbon dioxide fixation by a hydrogen-oxidizing bacterium

Abstract Fixing carbon dioxide (CO2) with solar hydrogen (H2) is a novel alternative to conventional photosynthesis of plants and microalgae. The energy efficiency of CO2 fixation by a hydrogen-oxidizing bacterium was investigated in a closed reactor system. The molar ratio of consumed H2 and CO2 was measured under mass transfer limitation in atmospheres of sufficient H2, low CO2, and a broad range of O2. The energy efficiency, ranging from 10% to 60%, was primarily affected by the oxygen concentration (6–30 mol%). The research revealed a clear trend that a low oxygen concentration gave high energy efficiency, but slow gas consumption. A high energy efficiency of 50% was measured under a moderate oxygen concentration (10 mol%). Based on 10% solar hydrogen efficiency, a 5% overall efficiency from solar energy to biomass can therefore be achieved.
Activation Energy Spectrum of a Biomolecule: Photodissociation of Carbonmonoxy Myoglobin at Low Temperatures

Carbon monoxide bound to myoglobin can be photodissociated with high quantum yield. The subsequent rebinding can be followed optically. In the temperature range between 40 and 200 K, rebinding can be described by a function of the form ${t}_{0}$, where $n$ and $H(t)={(1+\frac{t}{{t}_{0}})}^{\ensuremath{-}n}$ are temperature-dependent parameters. This behavior can be explained by assuming the existence of an activation-energy spectrum; the form of this spectrum is determined. The energy spectrum may be due to the existence of myoglobin conformers.
Outpatient treatment of moderate croup with dexamethasone: intramuscular versus oral dosing.

Objective. Steroid use for the treatment of croup has been supported by several studies, although few have addressed the use of oral dexamethasone for outpatient management. The efficacy of oral (PO) versus intramuscular (IM) dosing of dexamethasone in the outpatient treatment of moderate croup are compared in this study. Methods. Patients between the ages of 3 months and 12 years with moderate croup (history or presence of stridor, cyanosis, or retractions) were eligible for enrollment in this single-blind, prospective study. Patients were randomized to receive a single dose (0.6 mg/kg, maximum 8 mg) of IM or PO dexamethasone. Parents were contacted by phone to assess resolution of symptoms and need for further evaluation. Results. Two hundred seventy-seven patients were enrolled (median age: 2.1 years). One hundred thirty-nine patients received IM dexamethasone, and 138 received PO. At phone follow-up, 141 (51%) had total resolution of symptoms (75 in IM, 66 in PO). Eighty patients (29%) returned for further evaluation (45 in IM, 35 in PO). Twenty-three (8%) received either more steroids, racemic epinephrine, or admission (11 in IM, 12 in PO). Conclusion. No statistically significant difference was found in the need for subsequent interventions after a single dose of either IM or PO dexamethasone. A single PO dose of dexamethasone can be effectively and safely used for the outpatient treatment of moderate croup.
Sleep Problems in Children with Autism, ADHD, Anxiety, Depression, Acquired Brain Injury, and Typical Development

Comparative analysis of parent-reported sleep problems in clinical and typical children shows that (1) children with anxiety or depression sleep more than children with autism, ADHD-combined type, ADHD-inattentive type, acquired brain injury, and typical development; (2) children with autism have more sleep problems than children in the other diagnostic groups; (3) children with ADHD-inattentive type have the fewest sleep problems but have more daytime sleepiness than typical controls; (4) children with ADHD-combined type have more sleep problems than controls; (5) controls and children with ADHD-combined type have the least daytime sleepiness, and (6) children with brain injury have sleep problems scores in the midrange compared with all other groups.
High-Speed PIV Analysis Using Compressed Image Correlation

With the development of Holographic PIV (HPIV) and PIV Cinematography (PIVC), the need for a computationally efficient algorithm capable of processing images at video rates has emerged. This paper presents one such algorithm, sparse array image correlation. This algorithm is based on the sparse format of image data - a format well suited to the storage of highly segmented images. It utilizes an image compression scheme that retains pixel values in high intensity gradient areas eliminating low information background regions. The remaining pixels are stored in sparse format along with their relative locations encoded into 32 bit words. The result is a highly reduced image data set that retains the original correlation information of the image. Compression ratios of 30:1 using this method are typical. As a result, far fewer memory calls and data entry comparisons are required to accurately determine tracer particle movement. In addition, by utilizing an error correlation function, pixel comparisons are made through single integer calculations eliminating time consuming multiplication and floating point arithmetic. Thus, this algorithm typically results in much higher correlation speeds and lower memory requirements than spectral and image shifting correlation algorithms. This paper describes the methodology of sparse array correlation as well as the speed, accuracy, and limitations of this unique algorithm. While the study presented here focuses on the process of correlating images stored in sparse format, the details of an image compression algorithm based on intensity gradient thresholding is presented and its effect on image correlation is discussed to elucidate the limitations and applicability of compression based PIV processing.
Optimal transmission path search in power system restoration

Power system restoration is important for system planning and operation. It enables a grid to be restored from major outages efficiently and safely. The restoration process can be divided to three stages: starting generators, establishing transmission network, and restoring load services. After determining the start-up sequence of generating units, it is critical to find the shortest transmission path to energize transmission network using cranking power from available generators. This paper identified a set of logical constraints for transmission network energization, and formulated the transmission path search as a Mixed Integer Linear Programming (MILP) problem. These constraints could be easily incorporated with other restoration actions such as starting up generating units. Simulation results based on IEEE 39-bus test case demonstrate that the proposed MILP-based transmission path search algorithm is highly efficient and the restoration duration is significantly reduced.
Inhibition of rabbit sperm acrosomal enzymes by gossypol

The effect of gossypol on the activities of 10 acrosomal enzymes of the rabbit sperm was evaluated. Acrosin, Azocoll proteinase, neuraminidase, and arylsulfatase were significantly inhibited or completely inactivated by 12–76 μM gossypol. Hyaluronidase, β-glucuronidase, and acid phosphatase were inhibited only at a higher concentration of gossypol (380 μM). Phospholipase C, alkaline phosphatase, and β-N-Acetyl glucosaminidase were not inhibited even at 380 μM gossypol. Gossypol was found to be a noncompetitive inhibitor of arylsulfatase with a Ki of 120 μM. The inhibition was reversible and dose-dependent. As the acrosomal enzymes were more sensitive to the inhibition by gossypol compared to sperm enzymes involved in glycolysis or energy production, these assays may serve as a more reliable indicator for monitoring the occurence of gossypol-induced sterility. © 1995 Wiley-Liss, Inc.
The evolution of genetic regulatory systems in bacteria.

The genomes of bacterial species show enormous plasticity in the function of individual genes, in genome organization and in regulatory organization. Over millions of years, both bacterial genes and their genomes have been extensively reorganized and adapted so that bacteria occupy virtually every environmental niche on the earth. In addition, changes have occurred in the regulatory circuitry that controls cell operations, cell-cycle progression and responses to environmental signals. The mechanisms that underlie the adaptation of the bacterial regulatory circuitry are crucial for understanding the bacterial biosphere and have important roles in the emergence of antibiotic resistance.
A Cusped Field H- Ion Source for LAMPF

The addition of the Proton Storage Ring (PSR) to LAMPF requires the development of a more intense H/sup -/ ion source. The goals of this development program are to produce a beam of sufficient quality to match the acceptance of the accelerator and of sufficient intensity and duty factor to satisfy PSR operation as well as existing LAMPF requirements. The ion source concept best suited to these demands is the multi-cusp negative ion source being developed at LBL. The H/sup -/ ion source development was carried out on the high-voltage test stand in the LAMPF injector complex. The test stand, upgraded for the project, provides both unanalyzed and mass-analyzed beams to appropriate emittance scanning stations. Beam currents are measured using both beam current toroids and biased Faraday cups in both sections of the transport line. The emittance data are processed by the SEL 840 control computer at LAMPF. Ion source testing has been carried out using the extraction optics originally developed for the LAMPF duoplasmatron. Optics questions are being addressed by the plasma simulation code SNOW developed at Sandia. The accelerating column design will seek to minimize the divergence of the extracted beam and the predictions from SNOW will bemore » tested on the stand with actual H/sup -/ beams.« less
Identification of CYP2C19*4B : pharmacogenetic implications for drug metabolism including clopidogrel responsiveness

CYP2C19 is a principal enzyme involved in the bioactivation of the antiplatelet prodrug clopidogrel and common CYP2C19 loss-of-function alleles are associated with adverse cardiovascular events. To assess the impact of the CYP2C19*17 increased activity allele in the Ashkenazi Jewish (AJ) and Sephardi Jewish (SJ) populations and to determine the frequencies of additional variant alleles, 250 AJ and 135 SJ individuals were genotyped for CYP2C19*2–*10, *12–*17, *22 and P-glycoprotein (ABCB1) c.3435C>T. Importantly, CYP2C19*4, a loss-of-function allele, was identified in linkage disequilibrium with *17. This novel haplotype, designated CYP2C19*4B, significantly alters the interpretation of CYP2C19 genotyping when testing *17. Moreover, genotyping CYP2C19*17 changed the frequency of extensive metabolizers from ~70 to ~40%, reclassifying ~30% as ultrarapid metabolizers. Combining CYP2C19 and ABCB1 identified ~1 in 3 AJ and ~1 in 2 SJ individuals at increased risk for adverse responses to clopidogrel. These data underscore the importance of including *4B and *17 when clinically genotyping CYP2C19.
Functional Relations among Constructs in the Same Content Domain at Different Levels of Analysis: A Typology of Composition Models

Composition models specify the functional relationships among phenomena or constructs at different levels of analysis (e.g., individual level, team level, organizational level) that reference essentially the same content but that are qualitatively different at different levels (M. T. Hannan, 1971; K. H. Roberts, C. L. Hulin, & D. M. Rousseau, 1978; D. M. Rousseau, 1985). Specifying adequate composition models is a critical component of good multilevel research. A typology of composition models is proposed to provide a framework for organizing, evaluating, and developing constructs and theories in multilevel research. Five basic forms of composition are described and illustrated. Implications of the typology are discussed.
Self-Focusing in Photonic Crystal Defect Arrays

We study the self-focusing process in an array of photonic crystal defects and show that a net reduction in the self-focusing threshold intensity can be obtained even when the strength of linear diffraction is increased.
Nanoscale Confinement and Temperature Effects on Associative Polymers in Thin Films: Fluorescence Study of a Telechelic, Pyrene-Labeled Poly(dimethylsiloxane)

This study is the first to report on the tunability of associative polymer behavior via confinement and to model the effect against experimental data. A telechelic, associative polymer, α,ω-pyrene-end-labeled poly(dimethylsiloxane) (Py−PDMS−Py), was synthesized and studied via fluorescence spectroscopy in solution at room temperature and in the neat state as a function of confinement and temperature. Emission spectra were characterized by a ratio of excimer to monomer fluorescence intensity, IE/IM; excitation spectra were obtained at wavelengths characteristic of monomer and excimer emission. The spectra revealed a strong tendency for static excimer fluorescence originating from ground-state dimer or aggregate formation via pyrene−pyrene association at all concentrations of Py−PDMS−Py in polymeric or oligomeric poly(dimethylsiloxane) (PDMS). The aggregates form due to the insolubility of pyrene in PDMS. In contrast, in very dilute solution in toluene, a good solvent for both pyrene and PDMS, the low excim...
Factorization Properties for Isometries of Matroids into Projective Spaces

Let k, n ∈ ℕ, k ⩾ 2, n ⩾ 2 and let T be a class of desarguesian projective spaces, containing at least one projective space of order k and dimension n. We define μ (T, n, k) as the smallest m ∈ ℕ such that for every isometry α : V → P where V is a matroid of dimension n, |V|⩾ m, and P ∈ T has order k and dimension n, and for every isometry β : V → P′ ∈ T, there is a unique isometry γ : P → P′ such that β = γ ∘ α. We find lower and upper bounds for μ (T, n, k).
Candidate Taste Receptors in Drosophila

Little is known about the molecular mechanisms of taste perception in animals, particularly the initial events of taste signaling. A large and diverse family of seven transmembrane domain proteins was identified from the Drosophila genome database with a computer algorithm that identifies proteins on the basis of structure. Eighteen of 19 genes examined were expressed in theDrosophila labellum, a gustatory organ of the proboscis. Expression was not detected in a variety of other tissues. The genes were not expressed in the labellum of a Drosophila mutant,pox-neuro70, in which taste neurons are eliminated. Tissue specificity of expression of these genes, along with their structural similarity, supports the possibility that the family encodes a large and divergent family of taste receptors.
DOUBLE TRISOMY IN SPONTANEOUS ABORTIONS—AN 11 YEAR REVIEW

OBJECTIVE: To describe the different types of double trisomies diagnosed in spontaneous abortions. STUDY DESIGN: Retrospective review of spontaneous abortions with double trisomies, 1989-99. Maternal reproductive history was obtained by physician contact and medical record review. Data collection is ongoing. RESULTS: There were 42 cases of double trisomy; 20 (47.6%) female and 22 (52.4%) male. The mean maternal age was 39.6 years (22-46); the mean paternal age (n=21) was 40.9 years (33-53). The gestational age ranged 5.8 - 10.2 weeks. A fetal pole was seen in 15/25 (60%). The 16 double trisomies cited for the first time in this study were X/6, 3/21, 4/20, 6/8, 7/8, 7/21, 8/19, 8/21, 10/15, 12/21, 13/14, 14/15, 15/18, 15/marker, 16/18, 20/21. Two cases, X/6 and 8/21 were mosaic; one of the 2 cell lines had a single trisomy. The most common double trisomy was 15/21 (4 cases), followed by 15/20 (3 cases). The chromosomes that were trisomic in more than one double trisomy case were: numbers 21 (18 cases), 15 (14 cases), 20 (8 cases), 18 (7 cases), 16 (6 cases), 14 (5 cases), 8, 13, 22 (4 cases each); 6, 7 (three cases each), 17 (2 cases), and 3, 4, 10, 12, 19 (1 case each). Chromosomes 1, 2, 5, 9, and 11 were not found. Assisted reproductive technology was used in 12/33 cases (36%). Gynecologic pathology was seen in 15/28 (53%) of cases. Reproductive history prior to the index pregnancy (n=34), showed 8 livebom in 7 patients, and 41 spontaneous abortions in 20 patients. CONCLUSION: Advanced maternal age is associated with double trisomy. Chromosomes 21 and 15 are the most frequently involved chromosomes in double trisomy. The mean maternal age of 39.6 years in double trisomy appears higher than that reported for single trisomy, 31 years. This is the largest reported series of double trisomies in spontaneous abortion specimens. This information can aid in the genetic counseling of patients with spontaneous abortions and advanced maternal age.
Maternal Care, Iteroparity and the Evolution of Social Behavior: A Critique of the Semelparity Hypothesis

The Semelparity Hypothesis (Tallamy and Brown in Animal Behav 57:727–730, 1999) predicts that among insects with parental care that iteroparity will be rare. It represents two important challenges. First, life history ecologists have sometimes linked extended parental care with iteroparity, not semelparity, as part of a suite of correlated characters associated with K-selective environments. Second, behavioral ecologists have developed theories for the evolution of eusociality that rely upon a subsocial species producing multiple cohorts of offspring, a precondition for offspring allocare and/or inheritance of a social unit. Using a database of invertebrates exhibiting maternal care in Costa (The other insect societies. Harvard University Press, Cambridge, 2006), the association between semelparity and maternal care was tested using a broad comparative analysis. Semelparity was found in only 24.5 % of the best-studied representative species. In addition, semelparity was more rare in species that form nests, burrows or galleries (12.1 %) than in species that guard offspring out in the open (45.0 %). Iteroparity was common both among nesting species with non-overlapping broods (serial nesting) and in species where a female produces broods of different aged offspring in the same nest (within-nest iteroparity). It is hypothesized that common factors, particularly rapid juvenile development on high quality resources, facilitated both serial nesting and parental care. Within-nest iteroparity is an essential stage in the evolution of eusociality that has often been overlooked. Recent models of sibling conflict and reproductive spacing suggest that parental care can be an indirect cause of within-nest iteroparity despite the fact that parental investment can lead directly to diminished future reproduction. The reversal of this life history correlation may occur as a result of the transition between asocial and subsocial nesting behavior; analogous reversals may be a frequent outcome of transitions between levels of social organization.
Behavioral interactions produced by co-administration of 7-OH-DPAT with cocaine or apomorphine in the rat.

Previous research from our laboratory suggests that low doses (<0.1 mg/kg) of the dopamine (DA) D3-preferring agonist 7-hydroxy-N,N-di-n-propyl-2-aminotetralin (7-OH-DPAT) attenuate conditioned place preference (CPP) produced by the indirect DA agonist d-amphetamine, but enhance d-amphetamine-induced stereotypic behaviors. This study further examined the effects of 7-OH-DPAT on behaviors produced by the indirect DA agonist, cocaine, and the non-selective direct DA agonist, apomorphine. To examine whether 7-OH-DPAT would alter cocaine and apomorphine dose-response curves for motor behaviors and CPP, 0.1 mg/kg 7-OH-DPAT was co-administered with 0–30 mg/kg cocaine and 0–3 mg/kg apomorphine. To establish place conditioning, drug injections were paired with one of two distinctly different compartments, whereas saline injections were paired with the other compartment. Locomotion, sniffing, oral stereotypy, and headbobbing were measured following acute and repeated drug administration during conditioning, and place conditioning was assessed 24 h following the last conditioning day.7-OH-DPAT enhanced cocaine- and apomorphine-induced stereotypies following repeated administration. 7-OH-DPAT also attenuated cocaine-CPP, but potentiated apomorphine-CPP. Furthermore, 7-OH-DPAT attenuated locomotion produced by high doses of apomorphine. The attenuation of cocaine-CPP by 7-OH-DPAT likely involves stimulation of D2/D3 autoreceptors in the mesolimbic pathway, whereas the potentiation of apomorphine-CPP likely involves stimulation of D2/D3 postsynaptic receptors. Furthermore, it is suggested that attenuation of apomorphine-induced locomotion by 7-OH-DPAT likely involves stimulation of postsynaptic D3 receptors in the mesolimbic pathway. Thus, if postsynaptic D3 receptors are involved in mediating CPP and locomotion, then stimulation of D3 receptors may facilitate CPP but inhibit locomotion.
The relationship between skull morphology, biting performance and foraging mode in Kalahari lacertid lizards

Lizards are a diverse clade in which one radiation consists entirely of sit-and-wait foragers and another consists of wide foragers. Lizards utilizing these two foraging modes are known to differ in diet, but little is known about how feeding morphology relates to diet and/or foraging mode. This study tested the hypothesis that skull morphology and biting performance are related to diet preference, and consequently, coevolve with foraging mode. Four species of lacertid lizard were studied because they vary in foraging mode, their phylogenetic relationships are known and they are well studied ecologically. Using an ‘ecomorphological’ approach, skull morphology and biting performance were quantified and mapped on to the phylogeny for the species. The results indicate that sit-and-wait species have shorter, wider skulls than the wide foraging species, and that all are significantly different in overall head shape. The sit-and-wait species had similar values for biting performance; however, clear phylogenetic patterns of covariation were not present between sit-and-wait and wide foraging species for either biting performance or skull morphology. Thus, skull morphology and performance have little influence on diet and foraging mode in these species. Instead it is likely that other factors such as seasonal prey availability and/or life history strategy shape foraging mode decisions. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 140, 403‐416. ADDITIONAL KEYWORDS: bite force ‐ feeding ‐ functional morphology ‐ Lacertidae ‐ performance ‐ phylogenetic mapping.
Pitfalls of Deterministic Application of Nonlinear Site Factors in Probabilistic Assessment of Ground Motions

Abstract It is common for ground motions to be estimated using a combination of probabilistic and deterministic procedures. Probabilistic seismic hazard analyses (PSHA) are performed to estimate intensity measures (IMs) for reference site conditions (usually rock). This is followed by a deterministic modification of the rock IMs to account for site effects, typically using site factors from the literature or seismic codes. We demonstrate for two California sites and three site conditions that the deterministic application of nonlinear site factors underestimates ground motions evaluated probabilistically for return periods of engineering interest. Reasons for this misfit include different standard deviation terms for rock and soil sites, different controlling earthquakes, and overestimation of the nonlinear component of the site response in the deterministic procedure. This problem is solved using site-specific PSHA with appropriate consideration of nonlinear site response, within the hazard integral.
Polymerization in nonuniform latex particles. III. Kinetics of grafting in emulsion polymerization

The concept of nonuniform distribution of free radicals in polymerizing latex particles has been incorporated into the development of a kinetic model for grafting reactions. This theory permits prediction of grafting efficiency as a function of reaction conditions. It can also be used for evaluation of rate constants for grafting reactions. Experimental data for emulsion polymerization of styrene in the presence of polybutadiene seed latex have been used to assess the proposed grafting theory. The predominant grafting reaction appears to be the attack of growing polystyrene chains on the allyl hydrogen atoms of polybutadiene. The results further reinforce the hypothesis that the entering oligomeric free radicals do not distribute uniformly within the particle volume.
Reading the Writing in Radiology: 1923–2013

The style and tone of the writing in Radiology has changed over the years since its first publication in 1923. Many of the tonal changes have occurred transiently and likely in relation to political and professional issues in play at a particular time. Others represent more consistent trends in the evolution of the professional writing style. In this report, we analyze the tone of the editorial content from 1923 to 2013 in a historical context as well as progressive changes in readability parameters involving both editorial and technical content.