bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of sgcR3 in positive regulation of enediyne antibiotic C-1027 production of Streptomyces globisporus C-1027
Authors: Wang Lifei , Hu Yunfeng , Zhang Yanjuan , Wang Songmei , Cui Zhihui , Bao Yi , Jiang Wei , Hong Bin 
Published: March 2009

Abstract

Background
C-1027, produced by Streptomyces globisporus C-1027, is one of the most potent antitumoral agents. The biosynthetic gene cluster of C-1027, previously cloned and sequenced, contains at least three putative regulatory genes, i.e. sgcR1, sgcR2 and sgcR3. The predicted gene products of these genes share sequence similarities to StrR, regulators of AraC/XylS family and TylR. The purpose of this study was to investigate the role of sgcR3 in C-1027 biosynthesis.

Results
Overexpression of sgcR3 in S. globisporus C-1027 resulted in a 30–40% increase in C-1027 production. Consistent with this, disruption of sgcR3 abolished C-1027 production. Complementation of the sgcR3-disrupted strain R3KO with intact sgcR3 gene could restore C-1027 production. The results from real time RT-PCR analysis in R3KO mutant and wild type strain indicated that not only transcripts of biosynthetic structural genes such as sgcA1 and sgcC4, but also putative regulatory genes, sgcR1 and sgcR2, were significantly decreased in R3KO mutant. The cross-complementation studies showed that sgcR1R2 could functionally complement sgcR3 disruption in trans. Purified N-terminal His10-tagged SgcR3 showed specific DNA-binding activity to the promoter region of sgcR1R2.

Conclusion
The role of SgcR3 has been proved to be a positive regulator of C-1027 biosynthesis in S. globisporus C-1027. SgcR3 occupies a higher level than SgcR1 and SgcR2 in the regulatory hierarchy that controls C-1027 production and activates the transcription of sgcR1 and sgcR2 by binding directly to the promoter region of sgcR1R2.
Viral and murine interleukin-10 are correctly processed and retain their biological activity when produced in tobacco
Authors: Bortesi Luisa , Rossato Marzia , Schuster Flora , Raven Nicole , Stadlmann Johannes , Avesani Linda , Falorni Alberto , Bazzoni Flavia , Bock Ralph , Schillberg Stefan , Pezzotti Mario 
Published: March 2009

AbstractBackgroundInterleukin-10 (IL-10) is a potent anti-inflammatory cytokine, with therapeutic applications in several autoimmune and inflammatory diseases. Oral administration of this cytokine alone, or in combination with disease-associated autoantigens could confer protection form the onset of a specific autoimmune disease through the induction of oral tolerance. Transgenic plants are attractive systems for production of therapeutic proteins because of the ability to do large scale-up at low cost, and the low maintenance requirements. They are highly amenable to oral administration and could become effective delivery systems without extensive protein purification. We investigated the ability of tobacco plants to produce high levels of biologically-active viral and murine IL-10.ResultsThree different subcellular targeting strategies were assessed in transient expression experiments, and stable transgenic tobacco plants were generated with the constructs that yielded the highest accumulation levels by targeting the recombinant proteins to the endoplasmic reticulum. The best yields using this strategy in T1plants were 10.8 and 37.0 μg/g fresh leaf weight for viral and murine IL-10, respectively. The recombinant proteins were purified from transgenic leaf material and characterized in terms of theirN-glycan composition, dimerization and biological activity inin vitroassays. Both molecules formed stable dimers, were able to activate the IL-10 signaling pathway and to induce specific anti-inflammatory responses in mouse J774 macrophage cells.ConclusionTobacco plants are able to correctly process viral and murine IL-10 into biologically active dimers, therefore representing a suitable platform for the production for these cytokines. The accumulation levels obtained are high enough to allow delivery of an immunologically relevant dose of IL-10 in a reasonable amount of leaf material, without extensive purification. This study paves the way to performing feeding studies in mouse models of autoimmune diseases, that will allow the evaluation the immunomodulatory properties and effectiveness of the viral IL-10 in inducing oral tolerance compared to the murine protein.
Peroxisome proliferator-activated receptor-γ protects ERBB2-positive breast cancer cells from palmitate toxicity
Authors: Kourtidis Antonis , Srinivasaiah Rekha , Carkner Richard D , Brosnan M Julia , Conklin Douglas S 
Published: March 2009

Abstract
Introduction
Accumulation of fatty acids and neutral lipids in nonadipose tissues is cytotoxic. We recently showed that ERBB2-positive breast cancer cells produce significantly high amounts of fats, because of overexpression of the peroxisome proliferator-activated receptor (PPAR)γ-binding protein and the nuclear receptor NR1D1 (nuclear receptor subfamily 1, group D, member 1; Rev-erbα). These genes upregulate de novo fatty acid synthesis, which is a critical pathway for the energy production and survival of these cells. NR1D1 and PPARγ-binding protein are functionally related to PPARγ, a well established positive regulator of adipogenesis and lipid storage.

Methods
The effects of GW9662 and exogenously added palmitate on breast cells (BT474, MDA-MB-361, MCF-7, and human mammary epithelial cells) in monolayer culture were assessed. Mass spectrometric quantitation of fatty acids and fluorescence-based high content microscopy assays of cell growth, apoptosis, triglyceride storage and reactive oxygen species production were used.

Results
ERBB2-positive breast cancer cells are more sensitive to inhibition of PPARγ activity by the antagonist GW9662. PPARγ inhibition results in increased levels of total fats in the cells, mostly because of increased amounts of palmitic and stearic unsaturated acids. Administration of exogenous palmitate is lethal to ERBB2-positive but not to ERBB2-negative cells. GW9662 exacerbates the effects of palmitate addition on BT474 and MDA-MB-361 cells, but it has no significant effect on MCF-7 and human mammary epithelial cells. Palmitate administration results in a fivefold to tenfold greater increase in fat stores in ERBB2-negative cells compared with ERBB2-positive cells, which suggests that the ERBB2-positive cells have maximized their ability to store fats and that additional palmitate is toxic to these cells. Both PPARγ inhibition and palmitate administration result in increased reactive oxygen species production in BT474 cells. The cell death that results from this treatment can be counteracted by the antioxidant N-acetyl cysteine.

Conclusions
Our findings indicate that PPARγ activity enables ERBB2-positive breast cancer cells, which produce high levels of fat, to convert fatty acids to triglycerides, allowing these cells to avert the cell death that results from lipotoxicity. Endogenous palmitate toxicity represents a genetically based property of ERBB2-positive breast cancer that can be exploited for therapeutic intervention.
An Experimental Study of the Validity of a Delta J Criterion for Fatigue Crack Growth
Authors: Jablonski DA 
Published: March 2009

An experimental study was conducted to determine the validity of a delta J criterion for fatigue crack growth. Fatigue crack growth rates up to 0.10 mm/cycle were measured on compact tension specimens. Tests were conducted under delta J control using a computerized test system. Fatigue crack growth rates under variable delta J, J-increasing, constant delta J, and sloping-line test conditions were measured on 304 stainless steel and HY100 material. Linear elastic fracture mechanics crack growth rates were measured for comparison.
The results show that there is an excellent correlation between the fatigue crack growth rate and the effective J-integral range. The effective J-integral range was calculated from the area under the load/load-line displacement curve that was above the crack closure load. Correlation between the fatigue crack growth rate and the effective crack-opening displacement was poor. Correlations between the fatigue crack growth rate and the effective stress-intensity factor were poor for the 304 stainless steel and good for the HY100 material.
The crack closure behavior was measured for both materials. The crack closure loads were always compressive and either increased or decreased with crack length, depending upon the test type.
Military Aircraft
Authors: Hackman LE 
Published: March 2009

Military aircraft have utilized fiber reinforced composites for more than twenty years. The bulk of this use has been glass fiber reinforced plastics, which has provided both improved structural efficiency and lower cost. Recently, the advent of high modulus composites has led to its use in highly loaded, stiffness critical wings and control surfaces, as well as other structures.
This chapter details the major structural design approaches used for fiber composites in aircraft and summarizes several applications.
Measuring KR-Curves for Thin Sheets
Authors: Ripling EJ , Falkenstein E 
Published: March 2009

A modification of the tapered double cantilever beam specimen for measuring KR-curves of thin sheets is described. The modification consists of adhering properly contoured cover plates to the sheet to form a composite zero K-gradient (ZKG) specimen.
This testing procedure has a number of advantages over those presently used for plane stress testing:
1. K is proportional to the applied load and independent of crack length. Consequently, the specimen is stable, allowing for the collection of the complete KR-curve.
2. The testing procedure is simplified, and the instrumentation required to collect data, even at high rates, is relatively simple, since only load need be monitored.
3. Buckling is eliminated without the need of constraining members near the crack.
4. Cracking rate is related linearly to displacement rate.
Fracture Extension Resistance (R-Curve) Characteristics for Three High-Strength Steels
Authors: Judy RW , Goode RJ 
Published: March 2009

New procedures for characterizing the fracture extension resistance of ductile metals have been established. The fracture extension resistance curve (R-curve), which delineates the increasing rate of plastic work to cause crack propagation in nonbrittle metals, is determined by using dynamic tear (DT) test procedures. The resistance parameter is the slope of the R-curve.
The effect of thickness on the R-curve slope was investigated for three high-strength steels of high, intermediate, and low resistance to ductile fracture. R-curves were determined for each steel in the full thickness (1 in.) and for thicknesses of 0.625 and 0.325 in. The R-curve slopes showed good agreement for each section size, and a transition in the fracture mode from flat fracture at short crack extensions to the metal's characteristic degree of shear fracture for long extensions was observed for each steel. The data can be described by an exponential equation involving fracture energy, specimen cross-section dimensions, and a constant, Rp, which is proportional to the R-curve slope. For each steel, Rp is unaffected by changing specimen geometry, thus indicating it to be a material property.
Bacteria and the Assessment of Water Quality
Authors: Bott TL 
Published: March 2009

Bacteria are important in the assessment of water quality because certain organisms may be used as indicators of pollution of various types, and because bacteria possess diverse metabolic capabilities that bring about the mineralization of substances, many of which other organisms are unable to use. The limitations of the widely used coliform procedures are discussed and some new approaches to the detection of organisms of fecal origin are presented.
Methods for determining bacterial biomass are presented. However, measures of bacterial activity are more desirable because it is activity that will affect water quality. Some recent approaches to the measurement of bacterial growth and metabolism directly in natural habitats are presented.
Paper Fiber Filters for Sampling Trace Metals in Airborne Particulate Matter
Authors: Kometani TY , Bove JL , Nathanson B 
Published: March 2009

The standard collection filter medium for particulate air pollutants has been fiberglass. The high metal impurity content of glass and the tedious acid extraction procedure necessary to recover metals from particulates are great disadvantages when trace analysis is to be performed. Samples on paper filters, on the other hand, can be dry ashed to 500°C without serious loss of metals by volatilization. The filter is completely destroyed leaving only inorganic residue to be dissolved for analysis by atomic absorption spectrometry.
Analysis of New York City particulates collected on paper filters indicate that results obtained by dry ashing compare favorably with those of accepted methods such as wet ashing and low temperature ashing. Reported losses of metals during dry ashing of particulates on fiberglass filters are not necessarily due to volatilization as has been commonly supposed. Metals such as lead, zinc, copper, and cadmium are retained to glass to varying extents at high temperature either by formation of insoluble metal silicates or by physical entrapment by softened glass.
Color Evaluation of Foods—Correlation of Objective Facts with Subjective Impressions
Authors: Little AC 
Published: March 2009

In the early 1950's, a symposium entitled Color in Foods was arranged under the aegis of the National Academy of Sciences, National Research Council. The proceedings of that symposium have not to this day been superseded by a more up-to-date consideration of the state of knowledge as it has evolved since then.
At that time, considerable discussion was focused on the question of the validity of relating objective data to some visually determined and presumably imprecise scale. Because the opportunity has not presented itself to continue the vigorous exploration of this and other unresolved questions, the reservations and recommendations expressed in the proceedings stand unchallenged.
It is the purpose of this report to present a detailed discussion of the procedural framework developed by us to provide the basis for developing solutions for specific commodities and for specific purposes. The essentials include the development of model systems constructed to vary in known and controlled fashion along the requisite dimensions of color; the determination of optimum conditions for analyzing samples precisely and reproducibly for changes in physical and chemical properties which underlie changes in perceived color; the definition and construction of psychological scales which provide data relevant to the case in point; and finally, the demonstration of a highly significant relationship between visual evaluations and physically determined quantities. Thus, for different products, the same conceptual model is used; yet the procedural details may differ widely depending on the constraints imposed by physical and chemical characteristics of the sample and the specific requirements of the case. The feasibility of the approach will be explored with reference to actual examples.
Relationship of Instrumental Measurements to Visual Impressions of Potato Chip Color
Authors: Yeatman JN , Aulenbach BB 
Published: March 2009

A method was developed for preparing flat potato chips suitable for colorimetric measurement and visual evaluation. Flat potato chips were evaluated by three techniques: (1) colorimetric, including and excluding ultraviolet (UV) light in measuring beam to determine fluorescence effects; (2) spectrophotometric (380 to 740 nm), alternately backing chips with black or white reflector to permit calculation of light scattering; (3) visual, under controlled illumination by an experienced panel using a simple color-scoring system.
Excluding UV light increased Hunter aL and bL values. Although visual color scores under two luminaires (UV included and UV somewhat attenuated) were similar, greater attenuation of the UV light might affect visual impressions. Visual scores were highly correlated with Hunter L and aL, indicating that these instrumental measurements could be used to predict visual impressions of chip color. Munsell notations of chip color derived from spectrophotometric measurements backed with white reflector matched Munsell papers better than notations derived from data corrected for light scattering.
Color photographs were made of a series of flat potato chips with a Munsell gray scale in the frame register, permitting precise reproduction of a new visual color guide. The method of flat chip preparation for instrumental measurement and the visual color guide are offered as improved optional procedures in U.S. Standards for Grades of Potatoes for Processing.
Ordered Defect Structures in Irradiated Metals
Authors: Kulcinski GL , Brimhall JL 
Published: March 2009

The production of ordered defect structures in metals by neutron and charged particle bombardment is reviewed. Specific examples of a cubic array of aligned defect clusters are shown in nickel bombarded with 5-MeV nickel ions to 15 displacements per atom (dpa). The effect appears to occur only at temperatures between 280 and 450 C (536 and 842 F). Random defect arrays were found after 40, 180, 525, and 500 C (104, 356, 977, and 932 F) irradiation.
Ordered arrays of voids are shown in Ni nickel-irradiated to 300 to 400 dpa at 525 C and in molybdenum, Mo-0.5Ti, titanium-zirconium molybdenum alloy (TZM), columbium, tungsten, and tantalum irradiated with both neutrons and heavy ions. The structure of the voids is consistent with the parent lattice, that is, face centered cubic (fcc) in nickel and body centered cubic (bcc) in the refractory metals. A summary of the information reported to date reveals that the ratio of the lattice parameter of the void superlattice divided by the void radius varies from 5 to 17. The general features of the ordered void lattice are discussed in view of current theories that depend on strain interactions between the voids, anisotropic interstitial atom fluxes, and an approach to steady state at high displacement values.
Influence of Neutron Spectrum and Microstructure on the Postirradiation Creep-Rupture Behavior of an Austenitic Cr-Ni-Ti-B Steel
Authors: Böhm H , Wassilew C 
Published: March 2009

The influence of neutron irradiation on the postirradiation creep rupture properties of a 15Cr-15Ni-Ti-B steel and their dependence on microstructure and neutron spectra were studied. The steel was tested in three conditions: (a) solution treated at 1150 C (2012 F), (b) solution treated and aged at 1025 C (1877 F), (c) solution treated and aged at 900 C (1652 F). The conditions are characterized by an increasing amount of TiC precipitates going from treatment (a) to (c). The irradiations were carried out in the BR 2 reactor (Mol/Belgium) to a fast neutron fluence of 2 × 1021 n/cm2 (E &gt;0.1 MeV) and in the FR 2 reactor (Karlsruhe) to a thermal neutron fluence of 3 × 1020 n/cm2. The ratio of thermal to fast neutron flux was about 0.66 for BR 2 and 30 for FR 2 irradiations. The irradiation temperature was about 70 C (158 F). The postirradiation creep rupture tests were carried out at 650 C (1202 F).
The changes in creep rupture properties after irradiation were found to be strongly dependent on the neutron spectrum and the thermal pretreatment of the steel. The main results can be summarized as followed: 1. The fast thermal neutron irradiation in the BR 2 caused an increase in rupture life and decrease in creep rate of the steel in the solution-treated condition and also, but to a lower extent, in the 1025 C (1877 F) aged condition. With increasing stress the difference between the irradiated and unirradiated values diminished. 2. Irradiation in the FR 2 caused a decrease in rupture life and increase in creep rate of the 1150 and 1025 C (2102 and 1877 F) annealed conditions. The effect was more pronounced in the solution-treated than in the 1025 C annealed condition. The difference between the irradiated and unirradiated values decreased with decreasing stress. 3. There were no remarkable changes in creep rate and rupture life after irradiation of the steel in the 900 C (1652 F) annealed condition.
The results are discussed in terms of radiation-influenced precipitation processes superimposed by radiation-induced high-temperature embrittlement.
Effect of Neutron Irradiation on Vanadium
Authors: McIlwain JF , Chen CW , Bajaj R , Wechsler MS 
Published: March 2009

The effect of neutron irradiation on vanadium containing 50 to 800 weight ppm oxygen was studied using electrical resistivity, internal friction, and mechanical property measurements. The resistivity and internal friction specimens were irradiated to 3 × 1018 neutrons/cm2 (E &gt; 1 MeV) at −190 C(−310 F) and the tension test specimens were irradiated to 1.2 x 1019 neutrons/cm2 (E &gt; 1 MeV) at 106 C (223 F). Postirradiation annealing treatments were performed up to 220 C (428 F) for the resistivity and internal friction specimens and up to 520 C (968 F) for the tension test specimens.
Isochronal resistivity annealing measurements exhibited annealing stages at 170 C (338 F), 30 C (86 F), and −105 C(−157 F). The highest temperature stage (near 0.2 Tm, where Tm is the melting temperature) is attributed to the motion of interstitial oxygen to radiation-produced defect clusters and loops, where the oxygen is effectively removed from solid solution. This conclusion is based on the observations that: (a) the annealing activation energy is 1.1 ± 0.1 eV, close to the oxygen migration energy of 1.23 eV; (b) the magnitude of the annealing stage increased with increasing oxygen concentration; and (c) the decreases in oxygen concentration in solid solution upon annealing deduced from the decrease in resistivity and the decrease in the oxygen internal friction peak are in substantial agreement. The origins of the two lower temperature peaks are unknown, although it is speculated that hydrogen may be involved in the peak at -105 C (−157 F).
The yield stress measurements indicate that radiation exposure at 106 C (223 F) results in greater radiation hardening for specimens with larger oxygen concentration. Also, the further increase in strength upon postirradiation annealing (radiation-anneal hardening) is enhanced by increasing interstitial impurity concentrations.
Predicting the Fate of Chemicals in the Aquatic Environment from Laboratory Data
Authors: Branson DR 
Published: March 2009

Reasonable predictions of the fate of chemicals in the aquatic environment can be made from laboratory data. Some of the important data include evaporation, degradation, bioconcentration, and particulate adsorption. One of the more promising approaches for predicting fate is called “environmental rates approach” and requires that the laboratory data be expressed as rates. Suitable material balance models can then incorporate the environmental rates and predict exposure concentrations from a given rate of entry.
The “model ecosystem approach” is another way to predict fate. To evaluate model ecosystem data, the biodegradability index and ecological magnification values are compared with the biochemical oxygen demands and bioconcentration factors for a few benzene derivatives. Both types of data identify aniline and benzoic acid as the most susceptible to biodegradation in the series. Both also identify chlorobenzene and pentachlorophenol as the most accumulative in the series. Neither compound is as accumulative as DDT.
The main advantages of the environmental rates approach are the predictability of environmental concentrations at several points in time and the fundamental understanding of what happened to the chemical. The main advantages of the model ecosystem approach are the existing large data base and the identification of stable breakdown products as part of the test method.