cssi/SciSciGPT-SciSciNet huggingface dataset:
cea-kil operon of the ColE1 plasmid.

We isolated a series of Tn5 transposon insertion mutants and chemically induced mutants with mutations in the region of the ColE1 plasmid that includes the cea (colicin) and imm (immunity) genes. Bacterial cells harboring each of the mutant plasmids were tested for their response to the colicin-inducing agent mitomycin C. All insertion mutations within the cea gene failed to bring about cell killing after mitomycin C treatment. A cea- amber mutation exerted a polar effect on killing by mitomycin C. Two insertions beyond the cea gene but within or near the imm gene also prevented the lethal response to mitomycin C. These findings suggest the presence in the ColE1 plasmid of an operon containing the cea and kil genes whose product is needed for mitomycin C-induced lethality. Bacteria carrying ColE1 plasmids with Tn5 inserted within the cea gene produced serologically cross-reacting fragments of the colicin E1 molecule, the lengths of which were proportional to the distance between the insertion and the promoter end of the cea gene. Images
Loblolly Pine Tissue Culture: Laboratory, Greenhouse, and Field Studies

Conifer tissue culture had its beginnings in the late 1930s (10) and shoot regeneration cultures were first noted in 1950 (4). Since that time many species (7, 17), especially those using embryonic materials for starting expiants, have been cultured. Among some of the most studied species, Pinus radiata (2), Pseudotsuga menziesii (6), Pinus pinaster (8), Picea abies (22), and Pinus taeda (18), much laboratory data are accumulating. To date, little field data have been reported on the performance of tissue-cultured conifers (14), but several conifers are now established in field plantings (21) and data should be forthcoming.
Synthesis and assembly of barium-doped iron oxide nanoparticles and nanomagnets

A facile organic-phase synthesis of monodisperse barium-doped iron oxide (Ba-Fe-O) nanoparticles (NPs) is reported. The Ba-Fe-O NPs can be converted into hexagonal barium ferrite NPs at 700 °C, showing strong ferromagnetic properties with H(c) reaching 5260 Oe and M(s) at 54 emu g(-1). Moreover, the Ba-Fe-O NPs can be assembled into densely packed magnetic arrays, providing a unique model system for studying nanomagnetism and for nanomagnetic applications.
Protonated tert-pentyl dication (C5H122+, isopentane dication).

Structures of the tert-pentyl cation (C5H11+) and its protonated dication (C5H122+, isopentane dication) were studied using ab initio methods at the MP2/cc-pVTZ level. Both C–C and C–H hyperconjugatively stabilized structures 1 and 2, respectively, were found to be minima on the potential energy surface (PES) of the tert-pentyl cation. Structure 1 was computed to be about as stable as structure 2 (slightly more stable by 0.5 kcal mol–1). Inter-conversion between 1 and 2 through transition state 3 has a kinetic barrier of only 1.5 kcal mol–1. The C–H protonated form (H3C)2C+CH2CH4+4 was found to be the global minimum for the protonated tert-pentyl dication. Charges and 13C NMR chemical shifts of the dication 4 were calculated and compared to those of monocation 1 to study the effect of the additional charge in the dication.
Evidence for a Regulatory Role of Cholesterol Superlattices in the Hydrolytic Activity of Secretory Phospholipase A2 in Lipid Membranes

We have conducted a detailed study of the effect of membrane cholesterol content on the initial hydrolytic activity of Crotalus durissus terrificus venom phospholipase A2 (sPLA2) in large unilamellar vesicles of cholesterol/dimyristoyl-L-alpha-phosphatidylcholine (DMPC) and cholesterol/1-palmitoyl-2-oleoyl-L-alpha-phosphatidylcholine (POPC) at 37 degrees C. The activity was monitored by using the acrylodan-labeled intestinal fatty acid binding protein and HPLC. In contrast to conventional approaches, we have used small cholesterol concentration increments ( approximately 0.3-1.0 mol %) over a wide concentration range (e.g., 13-54 mol % cholesterol). In both membrane systems examined, the initial hydrolytic activity of sPLA2 is found to change with cholesterol content in an alternating manner. The activity reaches a local minimum when the membrane cholesterol content is at or near the critical cholesterol mole fractions (e.g., 14.3, 15.4, 20.0, 22.2, 25.0, 33.3, 40.0, and 50.0 mol % cholesterol) predicted for cholesterol regularly distributed in either hexagonal or centered rectangular superlattices. According to the sterol regular distribution model [Chong, P. L.-G. (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 10069-10073; Liu et al. (1997) Biophys. J. 72, 2243-2254], the extent of lipid superlattices is maximal at the critical cholesterol mole fractions, at which the membrane free volume is minimal. Thus, our present data can be taken to indicate that the initial hydrolytic activity of sPLA2 is governed by the extent of cholesterol superlattice. These data provide the first functional evidence for the formation of cholesterol superlattices in both saturated (e.g., DMPC) and unsaturated (e.g., POPC) liquid-crystalline phospholipid bilayers. The data also illustrate the functional importance of cholesterol superlattice and demonstrate a new type of regulation of sPLA2. Furthermore, upon binding to cholesterol/POPC large unilamellar vesicles, the intrinsic fluorescence intensity of sPLA2 shows an alternating variation with cholesterol content, exhibiting a minimum at the critical cholesterol mole fractions. This result suggests that either the number of sPLA2 bound to lipid vesicles or the conformation of membrane-bound sPLA2 or both vary with the extent of the cholesterol superlattice in the plane of the membrane.
Inhibition of prostate cancer growth by vinblastine and tamoxifen

Hormone refractory prostate cancer continues to be an aggressive and fatal disease. Agents which inhibit microtubule function have been found to be cytotoxic to prostate cancer cells in preclinical and clinical settings. It was the aim of this study to assess the activity of tamoxifen and vinblastine, two microtubule inhibitors, in hormone refractory prostate cancer. In clinically achievable concentrations, the combination of tamoxifen and vinblastine was cytotoxic to both Dunning rat prostate adenocarcinoma cell line MAT-LyLu (MLL) and human prostate cancer cells (PC-3). In cell cycle analysis assays, tamoxifen and vinblastine inhibited cell cycle transit. In vivo, these two agents inhibited the growth of implanted MLL cells. It appears that tamoxifen and vinblastine may be effective agents for the treatment of patients with hormone refractory prostate cancer.
Nonlinear traveling waves in rotating Rayleigh-Bénard convection: Stability boundaries and phase diffusion

We present experimental measurements of a sidewall traveling wave in rotating Rayleigh-B\'enard convection. The fluid, water with Prandtl number about 6.3, was confined in a 1-cm-high cylindrical cell with radius-to-height ratio $\ensuremath{\Gamma}=5.$ We used simultaneous optical-shadowgraph, heat-transport, and local temperature measurements to determine the stability and characteristics of the traveling-wave state for dimensionless rotation rates $60l\ensuremath{\Omega}l420.$ The state is well described by the one-dimensional complex Ginzburg-Landau (CGL) equation for which the linear and nonlinear coefficients were determined for $\ensuremath{\Omega}=274.$ The Eckhaus-Benjamin-Feir-stability boundary was established and the phase-diffusion coefficient and nonlinear group velocity were determined in the stable regime. Higher-order corrections to the CGL equation were also investigated.
Tunable thermal rectification in graphene nanoribbons through defect engineering: A molecular dynamics study

Using non-equilibrium molecular dynamics, we show that asymmetrically defected graphene nanoribbons (GNR) are promising thermal rectifiers. The optimum conditions for thermal rectification (TR) include low temperature, high temperature bias, ∼1% concentration of single-vacancy or substitutional silicon defects, and a moderate partition of the pristine and defected regions. TR ratio of ∼80% is found in a 14-nm long and 4-nm wide GNR at a temperature of 200 K and bias of 90 K, where heat conduction is in the ballistic regime since the bulk effective phonon mean-free-path is around 775 nm. As the GNR length increases towards the diffusive regime, the TR ratio decreases and eventually stabilizes at a length-independent value of about 3%–5%. This work extends defect engineering to 2D materials for achieving TR.
The relationship between futures trading activity and exchange rate volatility, revisited

Abstract This paper examines the relationship between trading activity in currency futures and exchange rate volatility. In order to measure trading activity, the paper uses both volume and open interest to distinguish between speculators/day traders and hedgers. The study uses three different measures of volatility: (1) the extreme value estimator that measures intra-day volatility; (2) historical volatility; and (3) conditional volatility from the GARCH (1, 1) process. Main finding is that speculators and day traders destabilize the market for futures. Whether hedgers stabilize or destabilize the market is inconclusive. The results suggest that speculators’ demand for futures goes down in response to increased volatility. Meanwhile, the demand from hedgers shows mixed results, depending on the method used to measure volatility.
Evaluation of the thermal stability of some nonlinear optical chromophores

Optical data storage is poised to benefit from a new class of advanced polymeric materials engineered to exhibit photorefractivity. Likewise, the transmission and processing of data will also benefit from a related class of materials with electro-optic activity. Organic chromophores are critical constituents of these materials which function due to a change of index of refraction in response to an electric field. However, a number of materials and processing problems remain to be solved before devices incorporating these optically nonlinear chromophores are practical. For example, for electrooptical applications the NLO waveguide should be able to withstand short duration processing temperatures in excess of 300°C and long duration use temperatures of at least 80°C. The requirement for thermochemical stability follows from the need to implement highTg matrices to provide stability of the orientational or polar order required for long-term device performance and reliability. As a result, the thermal stability of chromophores is now more closely evaluated in addition to their transparency and optical nonlinearity properties. Some chromophore classes, such as the azo dyes studied here, have attractive properties for these applications but further enhancements in overall properties are needed. Identification of the fundamental chemical processes in thermal decomposition of these dyes should lead to introduction of structural changes which provide better stability. Here thermogravimetric analysis (TGA) coupled with mass spectrometry (TGA/MS) is used to provide an assay of thermochemical stability with an added benefit that insight into the mechanisms of thermal decomposition may by identified. In this initial study diaryl substitution of the amine in derivatives of 4-amino-4′-nitroazobenzene was observed to greatly enhance thermal stability relative to dialkyl substitution. Substitution of phenyl for alkyl eliminates structural features involved in the most facile degradation mechanism available to the alkyl derivative.
Diversity and nectar hosts of flower-settling moths within a Florida sandhill ecosystem

The purpose of this study was to document and identify flower-settling moths within a Florida sandhill ecosystem and investigate their potential pollination capabilities. A combination of methods incorporating observation, morphology, pollen analysis and behaviour were applied. Fifty-two species of moths were documented taking nectar on flowers. A novel nectar-feeding behaviour categorized as fluttering resulted in increased pollen collection. Significant morphological match of moth proboscis length with flower corolla length was found. A preliminary list of sandhill moths is presented, and a pollen library of flowers found throughout the study area was created. This study was the first to conduct observations of settling moths in upland pine communities, and offers a rare glimpse into the interactions of moths with flowers within a unique ecosystem.
Bioconversion Reactions in Asphaltenes and Heavy Crude Oils

Interactions between select microorganisms and heavy crude oils in which the microorganisms have been introduced under controlled conditions proceed via a complex set of multiple biochemical and chemical reactions. Extensive studies in this laboratory have shown that such reactions are not random and differ from those involved in biodegradation of oils and follow distinct trends which can be categorized by means of characteristic chemical markers. These markers include mass spectrometric fragmentation patterns of light and heavy hydrocarbons, heterocyclic, organometallic compounds, trace metals, and the contents of heteroatoms. Bioconversion of heavy crude oils depends on the distribution of polar compounds containing nitrogen (N), sulfur (S), oxygen (O), and trace metals. The overall effects of induced biochemical reactions are a significant lowering (24-40%) of the N, S, O, and trace metal contents. Concurrently, there is also a redistribution of hydrocarbons (HC). The reactions are both biocatalyst and crude oil dependent and, in terms of chemical mechanisms, appear to involve the asphaltene and the associated polar fractions. Recent studies dealing with biochemical reactions in heavy crudes will be discussed.
All-optical slow-light on a photonic chip

We demonstrate optically tunable delays in a silicon-on-insulator planar waveguide based on slow light induced by stimulated Raman scattering (SRS). Inside an 8-mm-long nanoscale waveguide, we produce a group-index change of 0.15 and generate controllable delays as large as 4 ps for signal pulses as short as 3 ps. The scheme can be implemented at bandwidths exceeding 100 GHz for wavelengths spanning the entire low-loss fiber-optics communications window and thus represents an important step in the development of chip-scale photonics devices that process light with light.
Alternative therapies in management of leiomyomas.

Leiomyomas are benign soft-tissue neoplasms that arise from smooth muscle. Relief of symptoms (abnormal uterine bleeding, pain, pressure) is the major goal in management of women with significant symptoms. For symptomatic myomas, hysterectomy is a definitive solution; however, there are emerging less-invasive options. Magnetic resonance imaging–guided focused ultrasound surgery, cryomyolysis, and temporary occlusion of the uterine arteries are treatment options that are minimally invasive interventions with the benefit of preserving the uterus. This review summarizes procedure techniques, eligibility, complications, and outcomes of these alternate therapies.
The effect of rhPTH on the healing of tendon to bone in a rat model.

Successful rotator cuff tendon repair depends on secure tendon-to-bone healing. Recombinant human parathyroid hormone (rhPTH) has been shown in multiple studies to accelerate bone healing. Recent studies have also shown that rhPTH is chondrogenic by increasing chondrocyte recruitment and differentiation. We hypothesized that rhPTH would improve tendon-to-bone healing in a rat rotator cuff repair model. One hundred and fourteen Sprague Dawley rats underwent division and repair of the supraspinatus tendon. Fifty seven rats received daily subcutaneous injections of 10 µg/kg of rhPTH. Rats were sacrificed at 3, 7, 14, 28, and 56 days for histologic and immunohistochemical analysis. In addition, rats in each group were sacrificed at 14, 28, and 56 days for biomechanical testing and micro CT analysis. At 2 weeks the controls had a significantly higher load to failure than the rhPTH group. At 28 and 56 days there were no differences in load to failure. rhPTH specimens had significantly higher stiffness at 56 days. MicroCT analysis showed that the rhPTH group had significantly greater total mineral content at all time points, as well as significantly higher bone volume (BV) at 14 and 28 days. Histologically, the rhPTH specimens had more fibrocartilage, osteoblasts, and blood vessels at all timepoints, with significantly better collagen fiber orientation at 28 and 56 days. Although treatment with rhPTH resulted in an increase in bone and mineralized fibrocartilage formation, as well as better collagen fiber organization, this did not translate into improved biomechanical properties. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:769–774, 2012
Environmental epigenetics: prospects for studying epigenetic mediation of exposure–response relationships

Changes in epigenetic marks such as DNA methylation and histone acetylation are associated with a broad range of disease traits, including cancer, asthma, metabolic disorders, and various reproductive conditions. It seems plausible that changes in epigenetic state may be induced by environmental exposures such as malnutrition, tobacco smoke, air pollutants, metals, organic chemicals, other sources of oxidative stress, and the microbiome, particularly if the exposure occurs during key periods of development. Thus, epigenetic changes could represent an important pathway by which environmental factors influence disease risks, both within individuals and across generations. We discuss some of the challenges in studying epigenetic mediation of pathogenesis and describe some unique opportunities for exploring these phenomena.
Magnetic impurities in superconductors: A theory with different predictions.

The proclivity of paramagnetic solutes to degrade the transition temperature of a traditional singlet-pairing superconductor is studied anew. ${\mathit{T}}_{\mathit{c}}$ degradation is proportional to the (conduction electron) spin-disorder scattering rate, 1/${\mathrm{\ensuremath{\tau}}}_{\mathit{s}}$, caused by the solute spins. Accordingly the ${\mathit{T}}_{\mathit{c}}$ loss increases with solute concentration. The initial slope (versus 1/${\mathrm{\ensuremath{\tau}}}_{\mathit{s}}$) is found to depend on the superconductor and therefore is not the universal constant proposed by Abrikosov and Gor'kov. Instead the decrease is inversely proportional to \ensuremath{\lambda}, the electron-phonon coupling constant. Consequently a weak superconductor is doubly jeopardized by paramagnetic impurities: Its superconductivity is easily suppressed not only because ${\mathit{T}}_{\mathit{c}}$ is small to begin with, but also because the initial slope is steeper. Another unexpected consequence of the theory involves potential scattering which, acting alone, does not significantly influence ${\mathit{T}}_{\mathit{c}}$ (as surmised by Anderson). Nevertheless, the ${\mathit{T}}_{\mathit{c}}$ reduction caused by exchange scattering will be partially suppressed when the overall mean free path becomes smaller than the coherence length. This compensation has been demonstrated experimentally by comparing the influence of magnetic impurities in a pure host superconductor with that in a similar host having (also) nonmagnetic solutes. Such observed recovery of ${\mathit{T}}_{\mathit{c}}$, expected from this study, contradicts prior theories for magnetic solutes.
Clinical Policy: Critical Issues in the Prescribing of Opioids for Adult Patients in the Emergency Department

This clinical policy deals with critical issues in prescribing of opioids for adult patients treated in the emergency department (ED). This guideline is the result of the efforts of the American College of Emergency Physicians, in consultation with the Centers for Disease Control and Prevention, and the Food and Drug Administration. The critical questions addressed in this clinical policy are: (1) In the adult ED patient with noncancer pain for whom opioid prescriptions are considered, what is the utility of state prescription drug monitoring programs in identifying patients who are at high risk for opioid abuse? (2) In the adult ED patient with acute low back pain, are prescriptions for opioids more effective during the acute phase than other medications? (3) In the adult ED patient for whom opioid prescription is considered appropriate for treatment of new-onset acute pain, are short-acting schedule II opioids more effective than short-acting schedule III opioids? (4) In the adult ED patient with an acute exacerbation of noncancer chronic pain, do the benefits of prescribing opioids on discharge from the ED outweigh the potential harms?
Comparison of Three Soot Models Applied to Multi-Dimensional Diesel Combustion Simulations

In this paper, three soot models previously proposed for diesel combustion and soot formation studies are briefly reviewed and compared. The three models are (1) two-step empirical soot model, (2) eight-step phenomenological soot model, and (3) complex-chemistry coupled phenomenological soot model. All three models have been implemented into the KIVA-3V simulation code. For comparison, a heavy-duty DI diesel engine case with fuel injection typical of standard DI diesel operating conditions was studied. Flame structures of a single diesel spray predicted using these three models were compared, and the results offer our perspective on the application of these three models to soot modeling in diesel engines.
The T-lymphocyte is the primary cellular target for potentiation of the in vitro T-dependent IgM antibody response by the B subunit of cholera toxin.

Abstract The B (or binding) subunit of cholera toxin (CTB) was reported previously to potentiate the in vitro T-dependent IgM antibody response by a mechanism independent of the cyclic AMP-generating capacity of the intact toxin. In the present report, experiments were designed to determine the immune cell type mediating potentiation by CTB. Firstly, CTB did not potentiate T-independent antibody responses at concentrations that effectively enhanced T-dependent responses. Secondly, separation/reconstitution studies with splenocytes from CTB- and vehicle-treated mice demonstrated potentiation of T-dependent responses by CTB treatment of either the Sephadex G10 non-adherent population or the T-lymphocyte + macrophage population of cells. Potentiation was not observed by CTB treatment of the plastic adherent population or the B-lymphocyte + macrophage population. The evidence indicates that the T-lymphocyte is the primary cellular target for CTB-induced effects on the T-dependent IgM antibody response. Monosialoganglioside G M1 , the putative binding site for CTB, is most likely the site of action for CTB on T-lymphocytes. These studies provide new insight on the mechanism of immunomodulation by cholera toxin, and CTB should provide a useful tool for further understanding the role of gangliosides in cellular immune responses.
A Case of Acute Myeloid Leukemia with a Previously Unreported Translocation (14; 15) (q32; q13).

Background. We hereby describe what we believe to be the first reported case of t (14; 15) (q32; q13) associated with acute myeloid leukemia (AML). Methods. PubMed, Embase, and OVID search engines were used to review the related literature and similar published cases. Case. A47-year-old female presented in December 2011 with AML (acute myelomonocytic leukemia) with normal cytogenetics; molecular testing revealed FLT-3 internal tandem duplication (ITD) mutation, while no mutations involving FLT3 D385/I836, NPM1 exon 12, or KIT exons 8 and 17 were detected. She was induced with 7 + 3 (cytarabine + idarubicin) and achieved complete remission after a second induction with high-dose cytarabine (HiDAC) followed by uneventful consolidation. She presented 19 months after diagnosis with relapsed disease. Of note, at relapse cytogenetic analysis revealed t (14; 15) (q32; q13), while FLT-3 analysis showed a codon D835 mutation (no ITD mutation was detected). She proved refractory to the initial clofarabine-based regimen, so FLAG-idarubicin then was used. She continued to have persistent disease, and she was discharged on best supportive care. Conclusion. Based on this single case of AML with t (14; 15) (q32; q13), this newly reported translocation may be associated with refractory disease.
Continuous flow in packed thermal diffusion columns

A parallel-plate thermal diffusion column packed with glass wool was operated in continuous flow. The standard equation used for continuous flow through nonpacked columns satisfactorily correlates separation and flow rate. The packed-column theory correctly gives the effects on the regression coefficients of plate spacing and packing permeability, the two variables unique in the packed column. The theory gives poor approximations of the absolute magnitudes of the coefficients, however, which is the same situation found in results from nonpacked columns.
Nutrition : its role in bone health

At a given age, bone mass is determined by the amount of bone accumulated at the end of skeletal growth (the so-called peak bone mass), and by the amount of bone lost subsequently. Nutritional intake is an environmental factor that influences both bone capital accumulation, which is fully achieved by the end of the second decade of life, and bone loss, which occurs during the second half of existence. Nutrients may act directly by modifying bone turnover, or indirectly via changes in calciotropic hormone secretion. The study of the association between nutrition and a bone phenotypic expression may provide inconsistent results, in part because of the low accuracy and reproducibility of the various tools used to assess dietary intakes. Sufficient dietary calcium and protein are necessary for bone health during growth as well as in the elderly.
On the coevolution of pathogen and host: I. General theory of discrete time coevolution.

Abstract The theory of discrete time models of genetically conditioned coevolution is considered as an extension of classical population genetics theory. Strengths and weaknesses of the underlying assumptions are critically discussed in the context of host-pathogen interactions. Convenient formulae are provided to analyze the stability of equilibria. Some conclusions are drawn, which depend only on fairly general assumptions about the nature of host-pathogen coevolution.
Computer modeling for stabilities and structural relationships of n-hydrocarbons

Atom-atom spatial interactions were calculated for the four crystal packings known to exist in n-alkanes. Expression of end-group or mid-chain interactions as fractions of overall intermolecular interactions did not require use of the classical sixth power Lennard-Jones potential, yet allowed estimation of melting points within a given structural series and accurate prediction of the melting point of polyethylene. The calculations also provide a basis for explanation of structural relationships and stabilities among the four different n-paraffin forms.
Generation of mammalian cells expressing stably measles virus proteins via bicistronic RNA.

Abstract The proteins of measles virus are believed to be cytotoxic, and have never been expressed stably from the cloned genes in cultured cells. We found that measles viral proteins can be expressed via a bicistronic RNA. The dominantly selectable DHFR ∗ protein-coding region encoding a mutant dihydrofolate reductase was inserted into the 3'-untranslated regions of the measles viral genes encoding nucleoprotein (N), matrix (M) protein, and hemagglutinin (H). The tandemly arranged cistrons were placed under control by the inducible promoter of human metallothionein II A gene, or the noninducible early promoter of simian virus 40. Upon transfecting into mammalian cells, these gene constructs synthesized bicistronic RNAs. The downstream DHFR ∗ gene conferred resistance to methotrexate (MTX). Cells that survived MTX selection expressed stably the N, M, or H protein of measles virus. Expression of N protein was further inducible by cadmium chloride treatment. This system will be useful for studying the protein functions of measles virus, and could be applied to express other potentially toxic gene products.
Cardiovascular Manifestations of Hypereosinophilic Syndromes

The hypereosinophilic syndromes (HESs) are characterized by persistent marked eosinophilia (>1500 eosinophils/mm 3 ), the absence of a primary cause of eosinophilia (such as parasitic or allergic disease), and evidence of eosinophil-mediated end organ damage. Cardiovascular complications of HES are a major source of morbidity and mortality in these disorders. The most characteristic cardiovascular abnormality in HES is endomyocardial fibrosis. Patients who have an HES also may develop thrombosis, particularly in the cardiac ventricles, but also occasionally in deep veins. Because of the rarity of these disorders, specific guidelines for the management of the cardiac and thrombotic complications of HES are lacking. This article reviews the diagnosis and management of the cardiovascular manifestations of HES.
The Bidiagonal Singular Value Decomposition and Hamiltonian Mechanics

Computing the singular value decomposition of a bidiagonal matrix B is considered. This problem arises in the singular value decomposition of a general matrix, and in the eigenproblem for a symmetric positive-definite tridiagonal matrix. It is shown that if the entries of B are known with high relative accuracy, the singular values and singular vectors of B will be determined to much higher accuracy than the standard perturbation theory suggests. It is also shown that the algorithm in [Demmel and Kahan, SIAM I. Sci. Statist. Comput., 11 (1990), pp. 873–912] computes the singular vectors as well as the singular values to this accuracy. A Hamiltonian interpretation of the algorithm is also given, and differential equation methods are used to prove many of the basic facts. The Hamiltonian approach suggests a way to use flows to predict the accumulation of error in other eigenvalue algorithms as well.
Influenza-specific immunity induced by recombinant Listeria monocytogenes vaccines

In this study, we evaluate two Listeria monocytogenes strains that express influenza nucleoprotein (NP) sequences for their ability to protect against challenge with influenza-virus. The construction of one strain, which expresses only the Kd restricted NP epitope (NP 147-155), is described in this study; the other strain, which expresses the full NP sequence in the form of a fusion protein, has been described previously. The ability of the two strains to present the Kd restricted NP epitope in vitro and induce NP-specific CTL in vivo is also described. Mice immunized by the intravenous route with either strain cleared a subsequent (3 weeks post-immunization) influenza virus infection more rapidly as indicated by reduced virus titers in the lungs 5 days after challenge. Efficacy of both recombinant L. monocytogenes strains as vaccines in this system was equivalent and equal to that of recombinant vaccinia expressing NP.
Successful repair of an anterior cervical lip detachment associated with a spontaneous term delivery: A case report

Detachment of the cervix, either complete (annular) or partial, during labor is a rare complication.':" Management of this complication has been, in most instances, routine excision of the damaged cervix. I, 2, 4 With the exception of the report by Pelosi and associates," an attempt at repair has not been advocated. Therefore, the purpose of the following is to report a term delivery which took place through a partial detachment of the anterior lip of the cervix and successful postpartum repair.
Probabilistic input-output analysis: Modeling directions

Abstract Recent developments in probabilistic input-output modeling based on the full-distribution approach demonstrate the relationship between distributional forms of industry aggregates and regionally variant production characteristics. Variables such as market structure, establishment size, prices, labor productivity, technology, product mix, and ages of capital stock, all of which vary regionally, are determinants of the probabilistic structure of interindustry interaction. Two modeling directions are described in this paper. The first concerns formalizing the relationship between key variables at the regional level and particular forms of associated aggregate distributions. Once these relationships are specified, the dynamic character of interindustry structure can be developed. The second modeling direction follows on the first, and concerns the more general implications of the probabilistic perspective for regional economic modeling. One model demonstrated generates a nonlinear output growth path from a linear base-point projection of final demand. This model places the regional cyclical stability issue in a new light, and establishes a method for generating interval estimates of regional economic performance for forecasting purposes.
Optimal plant operation of brackish water reverse osmosis (BWRO) desalination

Abstract Optimal plant operation of brackish water reverse osmosis (BWRO) desalination is studied in this work to reduce specific energy consumption (SEC). A comprehensive first-principles based mathematical model, which explicitly accounts for membrane area and hydraulic permeability, pump characteristic curves, and pressure drops along the RO train, is developed and validated by plant data. A constrained nonlinear optimization is formulated and solved for two RO trains with different service times. It is shown that a 16% reduction in SEC is possible by optimizing operating conditions within the normal operating range of the pump while maintaining the same permeate rate. Results are discussed using dimensionless parameters derived in the author's previous work. Suggestions are made to further reduce SEC in BWRO plant operation.
Applications of intelligent telerobotic control

Abstract The telerobotics laboratory at Lawrence Livermore National Laboratory is a facility for developing and testing new concepts in robotics controls. Research and development is being conducted in computer vision; adaptive control; software architectures for real-time, intelligent control; artificial neural networks; fuzzy logic controllers; telepresence; and path planning and collision avoidance. The equipment in the telerobotics laboratory includes a six degree of freedom articulating robot arm with controller, gripper, and force and torque sensor; a 3D CAD workstation with software to model the work cell environment and simulate the robot dynamics; a six degree of freedom forceball for operator input to the telerobotics controller and the robot simulation; and a computer with a real-time operating system. Soon to be added are a 3D viewing system and a force reflecting hand controller. This paper describes one of the research and development efforts currently in progress on this program.
Composing user interfaces with InterViews

The authors describe a user interface toolkit, InterViews, that offers a rich set of composition mechanisms and a variety of predefined objects, allowing easy implementation of complex user interfaces. InterViews supports composition of three object categories, each implemented as a hierarchy of object classes derived from a common base class. The categories are interactive objects, structured graphics objects, and structured text objects. The authors present several simple applications and show how InterViews objects can implement their interfaces. They illustrate the benefits of separating interactive behavior and abstract data in several different contexts. They discuss InterViews support for end-user customization as well as the status of the current implementation. >
Photochemical Oxidation of As(III) in Ferrioxalate Solutions

Photochemical reactions involving aqueous Fe(III) complexes are known to generate free radical species such as OH• that are capable of oxidizing numerous inorganic and organic compounds. Recent work has shown that As(III) can be oxidized to As(V) via photochemical reactions in ferric-citrate solutions; however, the mechanisms of As(III) oxidation and the potential importance of photochemical oxidation in natural waters are poorly understood. Consequently, the objectives of this study were to evaluate oxidation rates of As(III) in irradiated ferrioxalate solutions as a function of pH, identify mechanisms of photochemical As(III) oxidation, and evaluate the oxidation of As(III) in a representative natural water containing dissolved organic C (DOC). The oxidation of As(III) was studied in irradiated ferrioxalate solutions as a function of pH (3−7), As(III), Fe(III), and 2-propanol concentration. Rates of As(III) oxidation (0.5−254 μM h-1) were first-order in As(III) and Fe(III) concentration and increased wi...
Predicting Party Sizes The 2007 Johan Skytte Prize Lecture

The Skytte Foundation states that I was awarded the Skytte Prize 2008 for 'profound analysis of the function of electoral systems in representative democracy'. What does this mean? As examples, I would highlight three relationships that qualify as laws in the strongest scientific sense. They do so because they offer a logically supported model as well as agreement with data, which gives them broad predictive ability. © 2009 Nordic Political Science Association.
The Resorption of Cilia in Cyathodinium piriforme

SYNOPSIS. The fine structure of the cilium, kinetosome, kinetodesmal fiber, and basal microtubules has been described in Cyathodinium piriforme. The ciliary axoneme is encased in an electron-dense jacket termed the axonemal jacket. This jacket surrounds the axoneme and is found midway between the axoneme and the ciliary membrane when viewed in cross section. Before division or reorganization the cilia are withdrawn into the cell. Intact cilia surrounded by their jackets are found in the cytoplasm during the early phases of retraction. Degradation of the axonemal microtubules precedes the dissolution of the axonemal jacket. Profiles of the jackets are observed after the microtubules have been resorbed. The cilia appear to detach from the kinetosomes. Barren kinetosomes are seen below the cell surface frequently with kinetodesmal fibers still attached. Whether all or some of these barren kinetosomes contribute to the formation of the new ciliary anlage cannot be ascertained.
Spectral and hyper eddy viscosity in high-Reynolds-number turbulence

For the purpose of studying the spectral properties of energy transfer between large and small scales in high-Reynolds-number turbulence, we measure the longitudinal subgrid-scale (SGS) dissipation spectrum, dened as the co-spectrum of the SGS stress and ltered strain-rate tensors. An array of four closely spaced X-wire probes enables us to approximate a two-dimensional box lter by averaging over dierent probe locations (cross-stream ltering) and in time (streamwise ltering using Taylor’s hypothesis). We analyse data taken at the centreline of a cylinder wake at Reynolds numbers up toR 450. Using the assumption of local isotropy, the longitudinal SGS stress and ltered strain-rate co-spectrum is transformed into a radial co-spectrum, which allows us to evaluate the spectral eddy viscosity, (k;k). In agreement with classical two-point closure predictions, for graded lters, the spectral eddy viscosity deduced from the box-ltered data decreases near the lter wavenumber k. When using a spectral cuto lter in the streamwise direction (with a box-lter in the crossstream direction) a cusp behaviour near the lter scale is observed. In physical space, certain features of a wavenumber-dependent eddy viscosity can be approximated by a combination of a regular and a hyper-viscosity term. A hyper-viscous term is also suggested from considering equilibrium between production and SGS dissipation of resolved enstrophy. Assuming local isotropy, the dimensionless coecient of the hyper-viscous term can be related to the skewness coecient of ltered velocity gradients. The skewness is measured from the X-wire array and from direct numerical simulation of isotropic turbulence. The results show that the hyper-viscosity coecient is negative for graded lters and positive for spectral lters. These trends are in agreement with the spectral eddy viscosity measured directly from the SGS stress{ strain rate co-spectrum. The results provide signicant support, now at high Reynolds numbers, for the ability of classical two-point closures to predict general trends of mean energy transfer in locally isotropic turbulence.
Tumor-suppressor genes: news about the interferon connection.

Abstract The interferons are a family of secreted, multifunctional proteins which are components of the defenses of vertebrates against viral, bacterial, and parasitic infections and certain tumors. They exert their various activities by inducing the synthesis of a large variety of proteins. There are direct and indirect indications that several of these proteins may have tumor-suppressor activities. The interferon-inducible proteins implicated include: (i) a double-stranded RNA-activatable protein kinase that can phosphorylate and thereby inactivate the eukaryotic peptide chain initiation factor eIF-2; (ii) the interferon regulatory factors IRF-1 and IRF-2, which can modulate the expression of the interferons and of some interferon-inducible proteins; and (iii) RNase L, a latent endoribonuclease which can be activated by (2'-5')oligoadenylates, the products of a family of enzymes which are also interferon-inducible. It is note-worthy that some of the proteins encoded by tumor virus oncogenes (e.g., E1A from adenovirus, EBNA-2 from Epstein-Barr virus, and terminal protein from hepatitis B virus) impair the induction of at least some proteins by interferons.
Kinetics of activation of acetylcholine receptors in a mouse muscle cell line under a range of acetylcholine concentrations

We studied, using the patch-clamp technique, the kinetics of single acetylcholine (ACh)-activated channels in a mouse muscle cell line. In the presence of high ACh concentrations we estimated the rate of channel isomerization into the open state (beta) from the dwell time between openings. Also, we obtained estimates for beta under low agonist concentrations by assuming a linear sequential model of channel activation and applying burst analysis. If the linear model is correct, then the two estimates of beta should agree since beta should be independent of ACh concentration. However, the estimates of beta obtained under low ACh concentrations were slower than those obtained independently under high ACh concentrations. The discrepancy in the estimates of beta suggests that the linear model is inadequate, but the discrepancy can be explained if open channels can close through two separate pathways. Two alternative kinetic models that can account for our data are discussed.
Control of ZnO nanorod array alignment synthesized via seeded solution growth

Abstract The critical factors that determine the degree of alignment of dense ZnO nanorod (NRAs) arrays synthesized via a two-step seeding and solution growth process were systematically examined, with a goal of optimizing the array density and surface area for hybrid organic–inorganic photovoltaic (PV) devices. Unexpectedly, we found that the degree of alignment of ZnO nanorod arrays depended strongly on the ambient humidity level during the seeding step. Close-packed ZnO nanorod arrays with [0 0 1] axis perpendicular to the substrate were obtained only when seeded at >20% relative humidity (RH) at room temperature (RT), according to data from scanning electron microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL) spectroscopy. In addition, when the seeding RH was raised to >60%, the polydispersity in the diameter and length of the ZnO nanorods increased, although good alignment was maintained. As a result, we determined an optimal seeding humidity of 30–40% for the synthesis of ordered ZnO nanorod arrays. Atomic force microscopy and contact angle measurements revealed that the density of ZnO seeds was significantly lower below the 20% relative humidity threshold, indicating that water vapor plays a critical role in generating insoluble zinc hydrolysis products that act as nucleation sites for the subsequent growth of ZnO nanorods. Finally, we found that the alignment of the ZnO nanorod arrays was strongly disrupted as the roughness of the underlying fluorinated tin oxide substrate increased. The improved control of the morphology of ZnO nanorod arrays may lead to improved carrier collection of conducting polymer-ZnO nanorod array hybrid PV devices.
Impact of nitrate enrichment on wetland and dryland seed germination and early seedling development

Questions Atmospheric and agricultural inputs of nitrogen have increased significantly. Because riparian zones act as buffers for nutrient transfer and treated municipal effluent and untreated agricultural run-off are released into streams, and because desert riparian ecosystems contain a wide range of functional groups with respect to water relations, we asked if wetland and dryland species respond differently to increasing levels of soil nitrate. Specifically, we asked if seed germination rate, total percentage germination and seedling development varied by species and functional group in response to increasing nitrate levels. Location Southwestern US. Methods We subjected seeds of common wetland and dryland species to distilled water (control), 0.025 M (low), 0.05 M (intermediate) and 0.075 M (high) KNO3 treatments for 30 days. We determined seed germination rates, total percentage germination and seedling development for each species. Generalized linear mixed models tested for differences between treatments. Results Seeds of wetland species germinated rapidly and in high percentages, and developed into seedlings regardless of nitrate treatments. Dryland species had unique responses to nitrate treatments, with some species exhibiting high germination rates in control treatments and others showing strong germination responses at low to intermediate nitrate levels. A larger number of dryland germinants developed into seedlings under control to low nitrate treatments. Conclusions Riparian plant community dynamics arising from germination responses could change under increased nitrogen inputs, as some species are seemingly unaffected and others significantly impacted. Based on our limited species pool and treatment conditions, the functional group ‘wetland species’ produces a consistent germination and early seedling response regardless of nitrate concentration, while ‘dryland species’ responses are variable and species-specific. Species known to be nitrophiles can be inhibited by high nitrogen concentration as germinants, highlighting the importance of investigating plant community response to changing conditions at a variety of life stages.
Diagnosing Depression in Older Adults in Primary Care

Depression is less prevalent among older adults than in other age groups, but the number of antidepressant prescriptions does not match this trend. Many patients are treated in primary care settings, where diagnosis and treatment of depression need improvement.