cssi/SciSciGPT-SciSciNet huggingface dataset:
Experimental Studies of Multi-Wire X Pinches on the Cobra Pulsed Power Generator

Summary form only given. The rebuilt COBRA pulsed power generator, which provides a variable current pulse (e.g., 100-150 ns rise-times; 0.6-1 MA peak current), has extended the range of parameters that can be used to study X pinches at Cornell University. X pinches constructed with two to twelve wires of materials that range from aluminum to tungsten, including alloys such as Invar, have been tested. Selected wire diameters typically ranged from 12.5 to 75 mum. In all cases, attempts were made to minimize the axial length over which the wires touched at the cross point. The influence of various pulse shapes on the formation of X-pinch plasma, as well as on the general dynamics of the pinch implosion process, has been studied using a set of diagnostics with either spatial or temporal resolution. A set of XUV, soft X-ray, and hard X-ray sensitive photodiodes, such as XRD, PCD, and AXUV-HS, were used with various filters to study the X-pinch radiation over a wide energy range that spanned from XUV up to 50 keV X-rays. There were two general setups employed to study the dynamics of X pinches on COBRA. The first consisted of two X pinches placed in the electron return current circuit, along with a cylindrical wire array serving as the primary load. This setup enabled the study of two X pinches, as well as provided X-ray backlighting for wire array imaging. The X pinches replaced two of the four standard return current posts that connect to the anode hardware. Currents going through the two X pinches, and through the remaining two return current posts were all measured separately. The other general setup studied was that of a standard X pinch load on COBRA. For both setups, a spherically bent, mica crystal spectrograph was used in addition to a flat KAP crystal spectrograph to monitor the soft X-ray self-emission of the X pinches, the results of which are presented herein. Over the course of these experiments, observed current pulses were grouped into two categories, characterized by two peaks separated in time by approximately 50-75 ns. When the first peak was the larger of the two, the X pinch generated a smaller, hotter plasma than when the second peak was the larger. The influence of the two current shapes on the micro-pinch plasma parameters and on the soft X-ray energy yield is discussed in detail
PbS quantum dots embedded TiO 2 nanofibers for dye-sensitized solar cells

We report a new type of dye-sensitized solar cells (DSSCs) fabricated using PbS quantum dots (QDs) embedded TiO 2 fibers as the photoanodes. QDs have shown great potential as an efficient light absorbing material with very high extinction coefficient. However, to obtain an efficient photoinduced charge transfer from QDs to TiO 2 , a stable linker is needed to attach QDs to TiO 2 . Unlike Ru based or all-organic dyes having a carboxylic group to function as the linker, it is a challenge to establish a strong attachment between QDs and TiO 2 . In this work, we used electrospinning technique to form TiO 2 nanofibers embedded with PbS QDs without the need of a carboxylic group or any other linker. The QDs embedded TiO 2 nanofibers were mixed with an organic binder and then deposited onto fluorine-doped tin dioxide (FTO) glass substrates by doctor blading. To harvest both visible and infrared light, the photoanodes were further sensitized with a Ru complex dye (Z-907). DSSC devices were fabricated using platinum as a counter-electrode catalyst for triiodide reduction. The cells achieved overall energy conversion efficiency of 2.8 % with Voc =0.81V and FF=0.61 under illumination of 100 mW/cm2 with an AM 1.5 filter.
A search for the circuitry of directional selectivity and neural adaptation through three-dimensional analysis of the outer plexiform layer of the rabbit retina

The circuitry of a part of the outer plexiform layer in the rabbit retina was studied by means of three-dimensional analysis based on electron micrographs of serial sections. 1. A methodology was worked out for such analysis involving large volumes of nervous tissue. Such analysis was evaluated as feasible and technically possible to pursue. 2. The analysis involved the complete circuitry of one β-type photoreceptor cell and was extended to involve all contact relations within the serially sectioned volume of retinal tissue of all processes contacting this photoreceptor cell. 3. The β-type photoreceptor cell was contacted by ten bipolar cell processes and nine horizontal cell processes. Several different contact relations were observed: contacts through endings at synaptic ribbon complexes, through invaginated endings not contacting synaptic ribbon complex components, through endings making superficial contacts without being invaginated. 4. A thorough analysis of the topographic relationships at synaptic ribbon complexes showed a consistent pattern of arrangement of horizontal cell and bipolar cell endings. 5. At the base of the photoreceptor cell terminal, the processes contacting the terminal formed a compact aggregation of branching processes. This structure was referred to as the subsynaptic neuropil and was proposed to play a role in the circuitry of the outer plexiform layer as indicated by the presence of special end branches confined to this region. 6. Bipolar cell endings were observed containing large amounts of synaptic vesicles and other cytoplasmic structures and were proposed to furnish presynaptic endings of efferent bipolar cells. These cells would allow a feedback from the inner plexiform layer to the outer plexiform layer. 7. These bipolar cell endings contacted horizontal cell endings lateral to the synaptic ribbon complexes. 8. An interpretation of the functional significance of the synaptic ribbon complexes was discussed. According to this interpretation, these complexes would form parts of the circuitry for neural adaptation of the retina. 9. Tight junctions and gap junctions were observed between the largest horizontal cell processes. 10. One bipolar cell process of the ten analyzed differed from the others by sending off lateral branches contacting several horizontal cells as well as one bipolar cell of the efferent type. 11. This bipolar cell was associated with a circuit that could possibly furnish the basis for directional selectivity of certain retinal units.
Polyoxomolybdate clusters and tetranuclear copper–organonitrogen complexes as building blocks for the design of three-dimensional oxide frameworks

Abstract The hydrothermal reaction of CuCl2·MoO, and 4,4′-bipyridylsulfide at 120 °C for 72 h yields yellow needles of {Cu(S-py2)}4Mo8O26]·2 H2O (MOXI-36). The structure is constructed from {Cu4(S-py2)4}4+ squares and [Mo8O26]4– clusters linked through CuO bonds into a three-dimensional assembly. The framework structure evolves from the linking of each {Cu4(S-py2)4}4+ cluster to four adjacent molybdate clusters, each of which in turn connects to four cationic clusters. Furthermore, the dimensions of the cationic building block, ca. 12.7 A on an edge, are sufficient to accommodate an interior anionic cluster, as well as the four clusters linked to the exterior surface. This produces a two-fold interpenetrated framework in which each {Cu4(S-py4)}4+ ring acts as a host to a [Mo8O26]4– cluster. © 2000 Academie des sciences / Editions scientifiques et medicales Elsevier SAS hydrothermal synthesis / three-dimensional oxides / polyoxomolybdates / tetranuclear organonitrogen complexes / host–guest relationships / X-ray crystallography
Soil Carbon Dioxide Flux in Antarctic Dry Valley Ecosystems

The Antarctic dry valleys of southern Victoria Land are extreme desert environments where abiotic factors, such as temperature gradients, parent material, and soil water dynamics, may have a significant influence on soil carbon dioxide (CO2) flux. Previous measurements of soil respiration have demonstrated very low rates of CO2 efflux, barely above detection limits. We employed a modified infrared gas-analyzer system that enabled detection of smaller changes in CO2 concentration in the field than previously possible. We measured diel CO2 fluxes and monitored soil microclimate at three sites in Taylor Valley. Soil CO2 flux ranged from −0.1 to 0.15 μmol m−2 s−1. At two of the three sites, we detected a physically driven flux associated with diel variability in soil temperature. At these sites, CO2 uptake (negative flux) was associated with dropping soil temperatures, whereas CO2 evolution (positive flux) was associated with increases in soil temperature. These observations are corroborated by laboratory experiments that suggest that CO2 flux is influenced by physically driven processes. We discuss four potential mechanisms that may contribute to physically driven gas exchange. Our results suggest there are strong interactions between biological and abiotic controls over soil CO2 flux in terrestrial ecosystems of the Antarctic dry valleys, and that the magnitude of either may dominate depending on the soil environment and biological activity.
Cluster analysis of Helicobacter pylori genomic DNA fingerprints suggests gastroduodenal disease-specific associations.

Background: Helicobacter pylori infection is now accepted as the most common cause of chronic active gastritis and peptic ulcer disease. The etiologies of many infectious diseases have been attributed to specific or clonal strains of bacterial pathogens. Polymerase chain reaction (PCR) amplification of DNA between repetitive DNA sequences, REP elements (REP-PCR), has been utilized to generate DNA fingerprints to examine similarity among strains within a bacterial species.Methods: Genomic DNA from H. pylori isolates obtained from 70 individuals (39 duodenal ulcers and 31 simple gastritis) was PCR-amplified using consensus probes to repetitive DNA elements. The H. pylori DNA fingerprints were analyzed for similarity and correlated with disease presentation using the NTSYS-pc computer program.Results: Each H. pylori strain had a distinct DNA fingerprint except for two pairs. Single-colony DNA fingerprints of H. pylori from the same patient were identical, suggesting that each patient harbors a single strain....
Magnetotransport properties of single-crystalline LaFeAsO

Measurements of magnetization, specific heat, electrical resistivity, Hall effect, and magnetoresistance on single crystalline samples of LaFeAsO grown in a NaAs flux are reported. While this material is known to be a semimetal, the temperature dependence of the electrical resistivity data presented herein is reminiscent of semiconducting behavior and exhibits distinct features associated with a structural transition and spin density wave (SDW) order. Low-temperature x-ray diffraction measurements have confirmed that the structural transition in these samples occurs near 140 K, compared to a transition temperature of 156 K observed in polycrystalline samples. Magnetoresistance and Hall coefficient measurements were performed in magnetic fields up to 9 T applied perpendicular to the basal plane using a van der Pauw configuration. The charge carrier density and mobility indicate that electrons are the majority charge carriers and exhibit features indicative of the structural transition and SDW formation. Isotherms of magnetoresistivity measured as a function of magnetic field can be scaled onto a single curve.
An international location and production transfer model for high technology multinational enterprises

SUMMARY International location decisions represent a major determinant of the manufacturing strategies of high technology enterprises. This paper studies the global location decisions of these companies and the cost dynamics experienced in manufacturing a single product over time. A set of assumptions and variable cost functions are developed to model a high technology firm's locational choices and transfer of production from domestic to foreign manufacturing sites. An enumeration procedure is presented that determines the minimum cost locational sequence of plant and host country locations required during a specified time horizon. Application of the mathematical model to a multinational enterprise scenario outlines the solution methodology.
Gender and Value Orientations—What’s the Difference!? The Case of Japan and the United States

This paper analyzes gendered social identity in Japan and the United States, countries with comparable postindustrial economic systems but distinct cultural traditions. Using national surveys (1995), we find gender differences in value orientations to be neither systematic nor consistent. They often disappeared after controlling for demographic and human-capital variables, though not so often for Japan. Other variables proved more important predictors of values than gender, although in different ways in Japan and the United States. We conclude by reassessing the use of the term gender in social research and the cultural meaning of gender relations by addressing the feminist concerns with issues of gender location.
Structural basis for methyl transfer by a radical SAM enzyme

The radical S-adenosyl-l-methionine (SAM) enzymes RlmN and Cfr methylate 23S ribosomal RNA, modifying the C2 or C8 position of adenosine 2503. The methyl groups are installed by a two-step sequence involving initial methylation of a conserved Cys residue (RlmN Cys355) by SAM. Methyl transfer to the substrate requires reductive cleavage of a second equivalent of SAM. Crystal structures of RlmN and RlmN with SAM show that a single molecule of SAM coordinates the [4Fe-4S] cluster. Residue Cys355 is S-methylated and located proximal to the SAM methyl group, suggesting the SAM that is involved in the initial methyl transfer binds at the same site. Thus, RlmN accomplishes its complex reaction with structural economy, harnessing the two most important reactivities of SAM within a single site.
Was money demand in the USA unstable before 1982? An application of the sup-F stability test

Abstract Models of US M1 demand have been subjected to repeated stability tests. The 1982 introduction of NOW accounts was only the final in a long series of apparent challenges for modeling. But traditional stability tests repeated over time inevitably lead to improper rejection of stability. The sup-F stability test controls for repeated testing and has been extensively studied in the econometrics literature but has been seldom applied. This paper applies the test to standard error-correction models 1948–1981. Stability cannot be rejected. Thus the apparent instabilities encountered in the 1970s can be removed from the agenda of challenges for empirical model specification.
Spin Hamiltonian of Low-Symmetry Crystalline Systems

The spin Hamiltonian has been developed for paramagnetic species found in crystalline sites of low (less than axial) symmetry. A tensorial form of the Hamiltonian has been stressed in order to emphasize its primarily mathematical origin and to clarify symmetry constraints. The treatment of these constraints, due to both Kramers (time-inversion) and spatial symmetry, is general without restrictive assumptions concerning the strength of the applied magnetic field. It is only assumed that the field-dependent interactions of the states described by the spin Hamiltonian with all other states can be treated as small perturbations. It has been shown that the spin Hamiltonian possesses the symmetry of the actual Hamiltonian if and only if the transformation matrices of the actual and fictitious spin states differ by at most a phase for every symmetry operation. Specific applications are to those terms of the spin Hamiltonian usually sufficient to describe the (approximately) orbital singlet states of a transition-metal ion with a fictitious electronic spin $s\ensuremath{\le}\frac{5}{2}$. However, the treatment may easily be extended to cover other terms, including those involving external electric fields and nuclear moments. Guidelines for the analysis and solution of the Hamiltonian matrix have been set out. Certain special reference frames of this Hamiltonian have been discussed, including and in particular the one designated by the symmetry axes of the orthorhombic point groups. The form of the Hamiltonian appropriate for this symmetry has been developed in detail. An operational definition of magnetic axes has been given and it has been shown that rotational studies can be effective in differentiating between orthorhombic, monoclinic, and triclinic site symmetries, when the paramagnetic ions substitute into several crystallographically equivalent sites.
Network Performance Modeling for PVM Clusters

The advantages of workstation clusters as a parallel computing platform include a superior price-performance ratio, availability, scalability, and ease of incremental growth. However, the performance of traditional LAN technologies such as Ethernet and FDDI rings are insufficient for many parallel applications. This paper describes APACHE (Automated Pvm Application CHaracterization Environment), an automated analysis system that uses an application-independent model for predicting the impact of ATM on the execution time of iterative parallel applications. APACHE has been used to predict the performance of several core applications that form the basis for many real scientific and engineering problems. We present a comparison of the performance predicted by APACHE with observed execution times to demonstrate the accuracy of our model. Finally, we present a method for a simple cost-benefit analysis that can be used to determine whether an investment in ATM equipment is justified for a particular workstation cluster environment.
Transverse effects in absorptive optical bistability

Abstract Absorptive bistability loops are computed for a laser beam with a gaussian input spatial profile incident on a unidirectional ring cavity containing a saturable nonlinear medium. Sharp radially dependent switching with wide bistable loops is predicted for large Fresnel numbers. Intermediate Fresnel numbers result in whole beam switching with significant narrowing of the associated bistable loops. At low Fresnel numbers, bistability can disappear. Radially integrated hysteresis loops differ quantitatively from plane-wave predictions.
Explaining Society: An Expanded Toolbox for Social Scientists

We propose for social scientists a theoretical toolbox containing a set of motivations that neurobiologists have recently validated. We show how these motivations can be used to create a theory of society recognizably similar to existing stable societies (sustainable, self-reproducing, and largely peaceful). Using this toolbox, we describe society in terms of three institutions: economy (a source of sustainability), government (peace), and the family (reproducibility). Conducting a thought experiment in three parts, we begin with a simple theory with only two motivations. We then create successive theories that systematically add motivations, showing that each element in the toolbox makes its own contribution to explain the workings of a stable society and that the family has a critical role in this process.
Adolescent Survivors of “Ethnic Cleansing”: Observations on the First Year in America

ABSTRACT Objective To describe the psychiatric assessments and trauma testimonies of 12 Bosnian adolescents newly resettled in America. Method : Twelve Bosnian adolescents who experienced the massive psychic trauma of “ethnic cleansing” were assessed during the first year after their resettlement in the United States. Assessments consisted of systematic, trauma-focused, clinical interviews that included standard assessment scales of posttraumatic stress disorder (PTSD) and depression, as well as the opportunity to give testimony about their experiences. Results PTSD was diagnosed in 25% of subjects and depressive disorders in 17%. Reexperiencing cluster symptoms were present in 50%, avoidance cluster symptoms in 31 %, and hypeararousal cluster symptoms in 29%. Conclusions The relatively low rate of PTSD in this sample (in comparison with adult survivors of “ethnic cleansing” and with Cambodian adolescent survivors) may be attributable to normal prior development, time-limited adversity, lack of physical or sexual traumas, rejoining nuclear families, or insufficient time for the development of delayed-onset PTSD. It may also be a reflection of the resiliency of adolescence. J. Am. Acad. Child Adolesc. Psychiatry , 1995, 34, 9:1153–1159.
Coordinate alterations in the expression of BRCA1, BRCA2, p300, and Rad51 in response to genotoxic and other stresses in human prostate cancer cells.

BACKGROUND BRCA1 and BRCA2 participate in cell cycle progression, apoptosis, and DNA repair pathways. The latter role may be mediated by interaction with DNA recombinase Rad51. The purpose of this study was to evaluate the effects of genotoxic and other cytotoxic agents on expression of DNA damage-response genes (BRCA1, BRCA2, p300, and Rad51) in human prostate cancer cells. METHODS Subconfluent proliferating cultures of Tsu-Pr1 or DU-145 cells were treated with various stressful agents and assayed 24 hr later for alterations in: 1) mRNA expression (by semiquantitative reverse transcription-PCR); 2) cell viability (by trypan blue dye exclusion); and 3) protein expression (by Western blotting). RESULTS Of 26 agents screened, BRCA1 and BRCA2 mRNA reductions were observed in both cell lines after exposure to adriamycin (ADR), camptothecin (CPT), sodium selenite (SLN), and ultraviolet radiation (UV), while nitrogen mustard (HN2) caused mRNA reduction in DU-145 but not in Tsu-Pr1. Inhibition of BRCA1/2 expression by ADR and HN2 was blocked by cycloheximide, suggesting that this requires new protein synthesis, while inhibition by CPT, SLN, and UV did not require protein synthesis. Reduction of p300 and Rad51 mRNA levels occurred in parallel with that of BRCA1/2, suggesting coordinate regulation of these genes. The ability of an agent to inhibit mRNA expression was not directly correlated with cytotoxicity. ADR, CPT, UV, and SLN also caused reduction of protein levels; but the kinetics of decreases in protein vs. mRNA differed. After ADR treatment, high molecular weight (Mr hyperphosphorylated) BRCA1 decreased more rapidly than the low Mr species. BRCA2 showed a more rapid decrease in protein than mRNA, while Rad51 showed the opposite. By 48 and 72 hr post-ADR, all four mRNAs and proteins were reduced to well below control levels, except for Rad51 protein, which was only moderately decreased. CONCLUSIONS Selected DNA-damaging agents (ADR, CPT, and UV) and a reducing agent (SLN) inhibited BRCA1/2, p300, and Rad51 expression in prostate cancer cells, although decreases in mRNA vs. protein did not coincide. We postulate that temporal changes in relative protein levels affect different phases of the stress response, and that the ultimate downregulation of all four genes promotes prostate cancer survival. Prostate 40:37–49, 1999. © 1999 Wiley-Liss, Inc.
GROWTH CHARACTERISTICS OF CELLS CULTURED FROM TWO MURINE MODELS OF POLYCYSTIC KIDNEY DISEASE

Polycystic kidney disease (PKD) is characterized by multiple renal cysts that are lined by epithelium and filled with fluid. PKD may result from one of a number of factors, either inherited or environmental. In this study, we have compared two mouse models in which PKD results from a genetic cause. In the C57BL/6J-cpk model, the mutated gene is unknown. In the other model, an SV40 large T antigen transgene causes renal cysts. We examined cultured cells from the kidneys of these mouse models, comparing growth characteristics. Although several features of PKD lead one to expect that the epithelial cells lining the cysts would have an increased rate of proliferation in culture, we found that they did not. The implications of these findings are discussed.
Scaling Violations in Quasielastic Electron Scattering

We study the phenomenon of y-scaling in inclusive quasielastic electron scattering. Emphasis is placed on the approach to scaling at finite four-momentum transfers, and the effects of final state interactions. Brueckner-Goldstone perturbation theory for nuclear matter is used to perform a detailed, microscopic calculation of the dynamic structure function of nuclear matter. This is compared to the naive prediction of the Impulse approximation, and we find that the approach to scaling is quite different. The Brueckner-Goldstone approach reproduces the trends seen experimentally (Impulse approximation does not); however, there is still not good quantitative agreement with the data. We take this to be a possible sign of problems in the conventional nucleon-nucleon interactions studied.
Alignment of Standards, Assessment and Instruction: Implications for English Language Learners in Ohio

The purpose of this article is to describe the process and development of English Language Proficiency (ELP) standards and assessment in Ohio and to discuss issues related to alignment. The article addresses the importance of alignment among standards, instruction, and assessment, as well as the effect of alignment on students' academic achievement. Additionally, a description is provided of measures used to show relationships among alignment of standards, assessment, instruction, and student outcomes. Finally, the authors review steps taken in Ohio to align ELP standards, content standards, instruction, and assessments.
A goal based cost-benefit analysis for film versus filmless radiology department

We describe the use of spreadsheet models to compare differential costs incurred in a film based versus a filmless radiology department. The spreadsheet allows a high degree of user customization to facilitate on-site cost analysis and informed purchasing decisions. Modeling institutions that perform 25, 50, and 105,000 diagnostic procedures per year, we find that break-even occurs near 50,000 exams. Plots further show the trends in annual hardware and staff costs as work loads increase.
Left Atrial Appendage Dimensions Predict the Risk of Stroke/TIA in Patients With Atrial Fibrillation

Risk of Stroke/TIA in Patients With Atrial Fibrillation. Introduction: Most strokes in patients with atrial fibrillation (AF) arise from thrombus formation in left atrial appendage (LAA). Our aim was to identify LAA features associated with a higher stroke risk in patients with AF using magnetic resonance imaging and angiography (MRI/MRA). Methods: The study included 144 patients with nonvalvular AF who were not receiving warfarin and who underwent MRI/MRA prior to catheter ablation for AF. LAA volume, LAA depth, short and long axes of LAA neck, and numbers of lobes were measured. Results: Of the 144 patients, 18 had a prior stroke or transient ischemic attack (TIA) (13 and 5, respectively). Compared with patients who had no history of stroke/TIA, these patients were older, had higher prevalence of hypertension and hyperlipidemia and had higher LAA volume (22.9 ± 9.6 cm3 vs. 14.5 ± 7.1 cm3, P < 0.001). Their LAA depth (3.76 ± 0.9 cm vs. 3.21 ± 0.8 cm, P = 0.006) and the long and short axes of the LAA neck (3.12 ± 0.7 cm vs. 2.08 ± 0.7 cm, P < 0.001; 2.06 ± 0.5 cm vs. 1.37 ± 0.4 cm, P < 0.001, respectively) were larger. Using stepwise logistic regression model, the only statistically significant multivariable predictors of events were age (OR = 1.21 per year, 95% CI 1.06-1.38, P = 0.004), aspirin use (OR = 0.039, 95% CI 0.005-0.28, P = 0.001), and LAA neck dimensions (short axis × long axis) (OR = 3.59 per cm2, 95% CI 1.93-6.69, P < 0.001). Conclusion: LAA dimensions predict strokes/TIAs in patients with AF. LAA assessment by MRI/MRA can potentially be used as an adjunctive tool for risk stratification for embolic events in AF patients. (J Cardiovasc Electrophysiol, Vol. 22, pp. 10-15, January 2011)
Selection of circularization sites in a group I IVS RNA requires multiple alignments of an internal template-like sequence

Circularization and reverse circularization of the Tetrahymena thermophila rRNA intervening sequence resemble the first and second steps in splicing, respectively. However, site-specific base substitutions show that different nucleotides are involved in selection of the 5' splice site and the circularization sites. Furthermore, a substitution at the major circularization site that prevents circularization can be suppressed by second substitutions at two different nucleotide positions. A model is proposed in which adjacent and overlapping sequences can function as a binding site, forming a short duplex with the sequence at the circularization site and thus directing circularization and reverse circularization. Because the 5' exon-binding site and three potential circularization binding sites fall within a contiguous eight nucleotide region, this sequence may translocate relative to the catalytic core of the ribozyme in a template-like manner.
A Chemical-Genetic Approach to Studying Neurotrophin Signaling

Trk tyrosine kinases are receptors for members of the neurotrophin family and are crucial for growth and survival of specific populations of neurons. Yet, the functions of neurotrophin-Trk signaling in postnatal development as well as maintenance and plasticity of the adult nervous system are less clear. We report here the generation of mice harboring Trk knockin alleles that allow for pharmacological control of Trk kinase activity. Nanomolar concentrations of either 1NMPP1 or 1NaPP1, derivatives of the general kinase inhibitor PP1, inhibit NGF and BDNF signaling in TrkA(F592A) and TrkB(F616A) neurons, respectively, while no such Trk inhibition is observed in wild-type neurons. Moreover, oral administration of 1NMPP1 leads to specific inhibition of TrkA(F592A), TrkB(F616A), and TrkC(F167A) signaling in vivo. Thus, Trk knockin mice provide valuable tools for selective, rapid, and reversible inhibition of neurotrophin signaling in vitro and in vivo.
Systemic administration of pharmacological agents and bone repair: What can we expect

Pharmacologic agents that modulate bone formation and bone remodelling are in broad use and development for the treatment of osteoporosis and other disorders of bone fragility. There is significant interest into the effect these agents may have on bone repair and fracture healing and whether these agents may be beneficial or detrimental to bone repair. Bisphosphonates delay callus remodelling, but increased callus volume seen during endochondral bone repair with bisphosphonate use allows for equivalent biomechanical properties for the fractured bone. Teripartide stimulates bone formation and in bone repair appears to have the potential to accelerate fracture callus formation and remodelling, potentially accelerating fracture healing. Animal models of fracture healing have demonstrated accelerated healing with larger callus volume, more rapid remodelling to mature bone, and improved biomechanical properties of the fractured bone. Clinical data with teriparatide has shown mixed results for its ability to stimulate fracture healing. Wnt signalling is one of the major pathways through which cartilage and bone formation is regulated during development. This same pathway has been identified as one of the ways that teriparatide stimulates bone formation. Antibodies to downstream proteins in this pathway, Dkk-1 and sclerostin, show significant promise of accelerating even normal fracture healing in preclinical animal models.
Solving the Currency Conundrum

This paper reviews the prospects for the exchange rate system in different parts of the world. It discounts radical changes like a single world currency and a trio of regional monetary unions: in Europe, where intergration is political as well as economic and financial, the euro should provide the basis for an expanding zone of monetary stability; in the Americas, in contrast, dollarization is likely to be the solution for countries with strong financial links to the USA that find it difficult to run an autonomous monetary policy; and in Asia, continued floating is the only plausible outcome, given the obstacles to the alternatives. (J.E.L.: F3)
Appraising freeze-drying for storage of bacteria and their ready access in a rapid toxicity assessment assay

Direct toxicity assessment (DTA) techniques seek to measure the impact of toxic chemicals on biological materials resident in the environment. This study features the use of freeze-dried bacterial cells in combination with a rapid DTA analyser, SciTOX. The effects of three factors-cryoprotectant type, bacterial strain, and storage temperature-were tested in order to validate the shelf life of the freeze-dried cells. Three freeze-dried Gram-negative bacterial strains, Acinetobacter calcoaceticus, Escherichia coli and Pseudomonas putida, were tested by using the bacteria in the SciTox(™) DTA assay and recording their responses to two standard toxicants: 2,4-dicholorophenol and 3,5-dichlorophenol. Each freeze-dried strain of bacteria was prepared in two forms--either pre-treatment with polyethylene glycol (PEG) or with sucrose/Tween 80--prior to storing at either 4 or -20 °C for three different storage periods (1, 2 or 3 months). While the sucrose/Tween 80 pre-treated freeze-dried cells exhibited better cell viability, we concluded that PEG was a more suitable cryoprotectant for the bacteria used in the DTA assay because of EC50 parity with fresh cell and zero-time freeze-dried cell assays. The results showed that freeze-dried cells, with appropriate materials and conditions, can give reproducible DTA results for up to 3 months. The availability of a biocomponent that can be activated by simple rehydration makes the deployment of this technology much easier for an end user.
Do coral reef fish learn to avoid unpalatable prey using visual cues

Colour and pattern provide important visual cues that affect animal behaviour. Learned avoidance of unpalatable prey by coral reef fish in response to visual cues has been studied before, but visual cues have not been separated from distastefulness to make certain that fish were learning solely in response to visual signals. Here, we used artificial foods to test the ability of wild-caught bluehead wrasse, Thalassoma bifasciatum, a common Caribbean reef fish, to learn to avoid unpalatable prey in laboratory experiments. First, we tested whether the relative position of foods of the same or different colours affected avoidance of unpalatable prey. Next, we tested whether blueheads could learn to avoid different colours of unpalatable prey. These experiments also tested whether blueheads could learn to avoid unpalatable prey against a pre-experimental colour bias. Finally, we determined whether blueheads learn to avoid unpalatable prey more effectively using colour or pattern signals. Fish learned to avoid unpalatable prey using colour independent of prey position, and they learned to avoid some colours (red, blue and orange), but not others (yellow, purple and green), based on visual cues alone. Fish avoided yellow, purple and green coloured prey, regardless of whether they were palatable or unpalatable. Fish only avoided white prey when unpalatable. Fish rapidly learned to overcome a strong pre-experimental bias against red prey. There was no difference in the ability of fish to learn to avoid prey using colour or pattern. We conclude that blueheads learn to avoid unpalatable prey using visual signals alone, that they have different responses to different colours and that they adapt quickly to novel prey appearance. Our results do not support the concept that specific prey colours, such as red or orange, strictly signal a chemical defence, but that blueheads continually assess and adapt to prey palatability using visual cues.
Clinical and Histopathologic Observations Concerning Hypotony After Trabeculectomy with Adjunctive Mitomycin C

Prolonged hypotony-induced maculopathy is a serious complication of trabeculectomy with adjunctive mitomycin C. We performed trabeculectomies with intraoperative mitomycin C on 59 eyes of 52 consecutive patients. Exposure time to mitomycin C was five minutes in the first seven patients, two of whom had prolonged hypotony-induced maculopathy. One of these required surgical revision of the filtering procedure. Light and electron microscopic study of the excised, avascular bleb disclosed an irregular epithelium and largely acellular subepithelium of loosely arranged connective tissue. In the remaining 52 eyes, the exposure time to mitomycin C was titrated between two and five minutes according to each patient's risk for failure of filtration from excessive fibrosis. Four additional cases of prolonged hypotony-induced maculopathy occurred among these 52 cases (7.7%), all of which were in the lower risk groups that received two- or three-minute exposure to mitomycin C. Four procedures failed, requiring further glaucoma surgery, and all of the patients were in the higher risk groups, receiving three- to five-minute exposures. Our titration of the exposure time to mitomycin C may have reduced, but did not eliminate, the risk of prolonged hypotony-induced maculopathy, and further study is needed to establish the optimum protocol for the use of this drug as an adjunct to trabeculectomy.
Lack of teratogenic effects of air at high ambient pressure in rats.

The purpose of the research was to determine if pregnant rats subjected to a maximum tolerated duration of exposure to air at 6 atmospheres absolute pressure (ATA) (50.3 meters seawater) would have an increased frequency of fetal death, resorption, low birth-weight, or malformations. Ninety pregnant rats were assigned to one of three exposure schedules during organogenesis: days 9–11, 12–14, or 15–17, and were randomized between one treatment and two control groups. The treatment group was subjected to 6 ATA for 70 minutes with compression and decompression at 1.8 ATA (18.3 meters seawater)/minute. Control groups were exposed to either 1 ATA of air (surface) within the hyperbaric chamber, or 1 ATA of air outside the chamber. For 30 minutes following decompression, chamber-treated animals were placed in a slow, motor-driven rotating cage, and assessed for gait disturbances from decompression sickness. On Day 20 of gestation, laparotomy was performed, and corpora lutea, implantations, and resorptions were counted. Fetuses were weighed, sexed, and examined for gross malformations. Subsequently, they were fixed, sectioned, and examined for visceral anomalies. Minor visceral anomalies and anatomical variations were present in 16.3% of all fetuses; however, no significant differences existed between groups. Similarly there were no significant differences when number of resorptions, number of dead fetuses, mean fetal weights, and malformations were compared by analysis of variance. Finally, there was no relation between symptoms of decompression sickness and any of the above measures. These results indicate that exposing rats to air at increased atmospheric pressure does not affect fetal health or survival.
Multifunctional Flexible Parylene-Based Intracortical Microelectrodes

Delivering drugs directly to the brain tissue opens new approaches to disease treatment and improving neural interfaces. Several approaches using neural prostheses have been made to deliver drugs directly with bypassing the blood-brain barrier (BBB). In this paper, we propose a new polymer-based flexible microelectrode with drug delivery capability. The probe was fabricated and tested for electrical and fluidic functionality in early stage design. In vivo chronic recording experiments succeeded in demonstrating the in vivo reliability of the probe. Successful in vivo experiments confirm the suitability of the probes as implantable chronic recording devices with robust fluid delivery function
Risk as Social Context: Immigration Policy and Autism in California.

Motivated by the dramatic increase in autism diagnoses in recent years, research into risk factors has uncovered substantial variation in autism prevalence by race/ethnicity, SES, and geography. Less studied is the connection between autism diagnosis rates and the social and political context. In this article, we link the temporal pattern of autism diagnosis for Hispanic children in California to state and federal anti-immigrant policy, particularly ballot initiative Proposition 187, limiting access to public services for undocumented immigrants and their families. Using a population-level dataset of 1992–2003 California births linked to 1992–2006 autism case records, we show that the effects of state and federal policies toward immigrants are visible in the rise and fall of autism risk over time. The common epidemiological practice of estimating risk on pooled samples is thereby shown to obscure patterns and mis-estimate effect sizes. Finally, we illustrate how spatial variation in Hispanic autism rates reflects differential vulnerability to these policies. This study reveals not only the spillover effects of immigration policy on children’s health, but also the hazards of treating individual attributes like ethnicity as risk factors without regard to the social and political environments that give them salience.
An Interferometric Method for High Extinction Ratio Measurements With 60-dB Dynamic Range

In this letter, we introduce a novel interferometric method for dynamic extinction ratio measurement of temporally demultiplexed pulses. A high extinction intensity modulator is used in order to temporally demultiplex the pulse train. The resulting extinction ratio is measured to be 44 dB. Our method has a dynamic range of ~60 dB. To our knowledge, this is the highest dynamic extinction ratio measurement method reported to date for high-speed optical modulators.
Does policy matter? The effect of increasing child care subsidy policy generosity on program outcomes

Abstract A dramatic change in the generosity of one state's child care subsidy policy provides an opportunity to study the relationship between subsidy policy generosity and program outcomes. We find positive effects of policy generosity on child care usage and continuity in the program. We also find these outcomes affected by employment characteristics of participating parents. Unstable employment as evidenced by frequent employment losses, job changes, and periods of unemployment, challenge the ability of a parent to remain in a program tightly linked to being employed. Generosity of subsidy policy is positively related to achievement of Child Care and Development Fund program goals of continuity and parental access to care that meets the developmental needs of their child.
THE GUNSHOT SOUND PRODUCED BY MALE NORTH ATLANTIC RIGHT WHALES (EUBALAENA GLACIALIS) AND ITS POTENTIAL FUNCTION IN REPRODUCTIVE ADVERTISEMENT

North Atlantic right whales (Eubalaena glacialis) make a short, distinctive broadband sound that is produced internally called a Gunshot sound. This sound has been recorded in the Bay of Fundy, Canada from both single whales (n= 9) and social surface active groups (n=49). Those single whales producing Gunshot sounds whose sex could be determined (n= 9) were all mature males. Gunshot sounds were produced as part of a stereotyped behavioral sequence by these individuals, including frequent head-lifts and flipper slapping at the surface. In surface active groups, Gunshot sounds were commonly recorded when males were present in the group. The rate of production of Gunshot sounds was weakly correlated with the total number of males present in the group. Given the behavioral context of Gunshot sound production, and production of the sound only by male whales, Gunshots may function in a reproductive context as an advertisement signal to attract females, an agonistic signal directed toward other males, or a combination of the two functions.
Comparison of the accuracy rates of 3-T and 1.5-T MRI of the knee in the diagnosis of meniscal tear.

OBJECTIVE. The purpose of this study was to compare the accuracy of 3-T MRI with that of 1.5-T MRI of the knee in the diagnosis of meniscal tear and to analyze the causes of diagnostic error.MATERIALS AND METHODS. We reviewed the medical records and original MRI interpretations of 100 consecutive patients who underwent 3-T MRI of the knee and of 100 consecutive patients who underwent 1.5-T MRI of the knee to determine the accuracy of diagnoses of meniscal tear. Knee arthroscopy was the reference standard. We retrospectively reviewed all MRI diagnostic errors to determine the cause of the errors.RESULTS. At arthroscopy, 109 medial and 77 lateral meniscal tears were identified in the 200 patients. With two abnormal MR images indicating a meniscal tear, the sensitivity and specificity for medial tear were 92.7% and 82.2% at 1.5-T MRI and 92.6% and 76.1% at 3-T MRI (p = 1.0, p = 0.61). The sensitivity and specificity for lateral tears were 68.4% and 95.2% at 1.5-T MRI and 69.2% and 91.8% at 3-T MRI (p = 1.0, ...
BioViews: Java-Based Tools for Genomic Data Visualization

Visualization tools for bioinformatics ideally should provide universal access to the most current data in an interactive and intuitive graphical user interface. Since the introduction of Java, a language designed for distributed programming over the Web, the technology now exists to build a genomic data visualization tool that meets these requirements. Using Java we have developed a prototype genome browser applet (BioViews) that incorporates a three-level graphical view of genomic data: a physical map, an annotated sequence map, and a DNA sequence display. Annotated biological features are displayed on the physical and sequence-based maps, and the different views are interconnected. The applet is linked to several databases and can retrieve features and display hyperlinked textual data on selected features. In addition to browsing genomic data, different types of analyses can be performed interactively and the results of these analyses visualized alongside prior annotations. Our genome browser is built on top of extensible, reusable graphic components specifically designed for bioinformatics. Other groups can (and do) reuse this work in various ways. Genome centers can reuse large parts of the genome browser with minor modifications, bioinformatics groups working on sequence analysis can reuse components to build front ends for analysis programs, and biology laboratories can reuse components to publish results as dynamic Web documents.
The Peritrophic Matrix Mediates Differential Infection Outcomes in the Tsetse Fly Gut following Challenge with Commensal, Pathogenic, and Parasitic Microbes

The insect gut is lined by a protective, chitinous peritrophic matrix (PM) that separates immunoreactive epithelial cells from microbes present within the luminal contents. Tsetse flies ( Glossina spp.) imbibe vertebrate blood exclusively and can be exposed to foreign microorganisms during the feeding process. We used RNA interference–based reverse genetics to inhibit the production of a structurally robust PM and then observed how this procedure impacted infection outcomes after per os challenge with exogenous bacteria ( Enterobacter sp. and Serratia marcescens strain Db11) and parasitic African trypanosomes. Enterobacte r and Serratia proliferation was impeded in tsetse that lacked an intact PM because these flies expressed the antimicrobial peptide gene, attacin , earlier in the infection process than did their counterparts that housed a fully developed PM. After challenge with trypanosomes, attacin expression was latent in tsetse that lacked an intact PM, and these flies were thus highly susceptible to parasite infection. Our results suggest that immunodeficiency signaling pathway effectors, as opposed to reactive oxygen intermediates, serve as the first line of defense in tsetse’s gut after the ingestion of exogenous microorganisms. Furthermore, tsetse’s PM is not a physical impediment to infection establishment, but instead serves as a barrier that regulates the fly’s ability to immunologically detect and respond to the presence of these microbes. Collectively, our findings indicate that effective insect antimicrobial responses depend largely upon the coordination of multiple host and microbe-specific developmental factors.