cssi/SciSciGPT-SciSciNet huggingface dataset:
Species differences in the production and clearance of 1,3-butadiene metabolites: a mechanistic model indicates predominantly physiological, not biochemical, control

Inhaled 1,3-butadiene, a monomer used in the production of synthetic rubber and other resins, is metabolized to mutagenic and carcinogenic epoxide intermediates. A physiologically based pharmacokinetic model of the uptake, tissue distribution, and metabolism of butadiene was constructed to determine if the biochemical kinetic constants obtained from in vitro studies are consistent with the observed in vivo uptake and metabolism. The model includes compartments for lung, blood, fat, liver, other rapidly perfused tissues ('viscera') and slowly perfused tissues. Metabolism of butadiene was assumed to occur in viscera in addition to lung and liver. Enzymatic reaction rate equations for the formation of 1,2-epoxy-3-butene, for hydrolysis of this epoxide, and for its conjugation with glutathione were also included. Physiological and biochemical parameters for the mouse, rat and human were obtained from the literature; they were not adjusted to produce a fit to experimental data. The model was used to test the hypothesis that differences in uptake and clearance of butadiene by the three species are due to differences in the activities of the metabolizing enzymes. The model reproduces whole-body observations for the mouse and rat. It predicts that inhalation uptake of butadiene and formation and retention of epoxybutene are controlled to a much greater extent by physiological parameters than by biochemical parameters and that storage in the fat represents a significant fraction of the retained butadiene. Accumulation of epoxybutene in the blood is predicted to be higher in mice than in rats or humans, but accumulation of the epoxide intermediate in the liver is predicted to be highest in humans. The epoxide tissue concentrations predicted by the model do not, by themselves, correlate with tumor incidence in mice and rats, indicating that other factors are crucial for carcinogenesis induced by butadiene.
Electrosurgical tissue resection: A numerical and experimental study

The optimization of electrosurgical procedures requires a rigorous understanding of the electrical, thermal, mechanical and chemical events accompanying the ablation process. Modeling is indispensable and is needed to further advance this technology. This study introduces a novel tissue electrosurgical ablation model based on interstitial vapor nucleation and expansion. The model describes interstitial vapor nucleation and bubble growth using a homogeneous nulceation theory and Rayleigh equation. Electrosurgical incisions were made on beef muscle while equivalent electrical circuit patameters were monitored as a function of power settings and scalpel geometries. Thermal damage was measured using light and polarization microscopy. Results were compared with predictions produced by a numerical simulation, which modeled the tissue and electrosurgical scalpel interaction as a function of power settings and scalpel geometry.
Use of the end-to-end anastomosis stapling device in low colorectal anastomosis associated with radical gynecologic surgery

Between 1978 and 1984, 49 rectosigmoid anastomoses were performed using the end to end anastomosis (EEA) stapler. Seventeen (35%) of the patients had prior radiation treatment. Twenty-eight (57%) of the anastomoses were at the level of the peritoneal reflection and 21 (43%) were at the level of the levators. Fourteen patients (29%) had diverting colostomies and 11 (79%) of these were closed. There were 5 complications (10%) directly related to the anastomosis. These included two strictures, two anastomotic breakdowns, and one case of fecal incontinence after colostomy closure. All complications arose in patients with prior radiation treatment.
Expression of follicle-stimulating hormone and luteinizing hormone receptor messenger ribonucleic acids in bovine follicles during the first follicular wave.

The objective of the present study was to characterize expression of mRNAs encoding FSH and LH receptors during follicular development and at different stages of the first follicular wave in cattle. Following estrus, groups of heifers (3-5 per group) were ovariectomized on the day of initiation of the first follicular wave (as determined by ultrasonography; Day 0), or on Days 2, 4, 6, 8, or 10 after initiation of the first wave. FSH and LH receptor mRNAs were detected within follicles > or = 4 mm and in some smaller follicles by in situ hybridization and were quantified by image analysis. FSH receptor mRNA was expressed in granulosa cells of all growing follicles, starting in some follicles with only one layer of granulosa cells. Irrespective of day of the follicular wave, the level of expression of FSH receptor mRNA in granulosa cells of healthy antral follicles ranging from 0.5 to 14 mm in diameter did not vary significantly with follicular size (r = 0.02, p > 0.10). Expression of LH receptor mRNA was first observed in theca interna cells of follicles shortly after antral formation. Irrespective of day of the follicular wave, the levels of LH receptor mRNA in theca interna cells of healthy antral follicles ranging from 0.5 to 14 mm increased with follicular size (r = 0.39, p 9 mm in diameter and was first observed in the dominant follicles collected on Day 4. Expression of mRNA for LH receptor, but not for FSH receptor, changed (p < 0.01) with the stage of the first follicular wave.(ABSTRACT TRUNCATED AT 250 WORDS)
Region-specific changes in NMDA receptor mRNA induced by chronic morphine treatment are prevented by the co-administration of the competitive NMDA receptor antagonist LY274614.

The steady-state mRNA levels of the NMDA receptor NR1 subunit were determined by a quantitative solution hybridization assay in selected CNS regions associated with antinociception in the rat. Tissues were obtained by microdissection from rats treated chronically with morphine alone or in combination with LY274614, a competitive NMDA receptor antagonist. Morphine treatment for 7 days resulted in the development of tolerance to morphine's analgesic effect and produced a significant decrease in the steady-state NR1 mRNA levels in the spinal cord dorsal horn (by 16%), and an elevation in nucleus raphe magnus and medial thalamus (by 26 and 38%, respectively). The NR1 mRNA levels were unchanged in the lateral paragigantocellular nucleus, locus coeruleus, periaqueductal grey, and sensorimotor cortex. NMDA receptor binding in the spinal cord measured with [3H]MK-801 was reduced approximately 50% by chronic morphine treatment. Co-administration of LY274614 (s.c. at 24 mg/kg/24 h via an osmotic pump) not only attenuated the development of morphine tolerance but also prevented the changes in the NR1 mRNA levels induced by chronic morphine administration. Neither a 7-day infusion of LY274614 nor an acute injection of morphine (10 mg/kg, s.c.) changed the NR1 mRNA levels. These results suggest that changes in the expression of the NR1 mRNA induced by chronic morphine in three CNS regions involved in antinociception are associated with the development of morphine tolerance and in the spinal cord, morphine tolerance is associated with the downregulation of NMDA receptors.
Estrogenic stimulation of cytidine uptake by the uterus

Abstract The uptake and distribution of 3H-cytidine by the uterus of the adult ovariectomized rat has been examined during the first 24 hours of estradiol action. There is no increase in uptake during the first 20 minutes. At 2 hours and subsequently tritium uptake into both the acid-soluble and RNA fractions of the uterus is increased, and there is a greater percentage increase in the labeling of acid-soluble 5′-CMP than of RNA. These results probably are the consequence of hormonal regulation of 3H-cytidine entry into the uterus. In ovariectomized controls the rate of nucleoside entry appears to be rate-limiting for phosphorylation. Estradiol increases the rate of cytidine entry sufficiently to allow an intracellular accumulation of the free nucleoside.
Effect of Diamond Dispersion on the Superplastic Rheology of Zinc Sulfide

The dispersion of diamond particles in superplastic zinc sulfide produces flow softening at low diamond concentrations, and hardening at high concentrations. The minimum in the flow stress is observed at 5 wt% (5.5 vol%) diamond content. The softening can be explained in terms of the grain refinement in the ZnS in the presence of diamond particles. The smaller grain size is shown to reduce the flow stress by enhancing the rate of diffusional creep. The hardening is believed to have been caused by the formation of a network among the diamond particles at high concentrations. The fact that the diamond particle size was approximately onethird the grain size of ZnS may have contributed to the network formation.
Understanding Emotional Response Theory: The Role of Instructor Power and Justice Messages

Emotional Response Theory (Mottet, Frymier, & Beebe, 2006) predicts that instructor communication stimulates student emotional responses that direct their approach–avoidance behaviors. To test this theory, students reported their perceptions of instructor communication (power and justice), student emotional responses (pleasure, arousal, and dominance), and indicators of their approach–avoidance (cognitive learning, affective learning, and state motivation). Emotional responses were superior predictors of cognitive learning and state motivation compared to instructor communication. However, instructor communication was a better predictor of affective learning compared to emotional responses. To test the causal nature of this theory, path analyses were employed. The models were not supported. Collectively, the theory was partially supported. Implications, limitations, future directions, and an assessment of the theory are discussed.
The effects of post-educational professional development activities on promotion and career satisfaction of IT professionals

Seeking new career opportunities and retaining IT jobs still require considerable time spent on various professional development activities. This study hypothesizes that these professional development activities are vital to organizational tenure as well as to career satisfaction. A survey was used to examine the effects of time spent on professional development activities on promotion and career satisfaction. The result showed that informal professional development activities had no effect on organizational tenure and career satisfaction, while formal professional development activities contributed most to the progress of an IT career. Strategies and explanations for these findings are discussed.
Urinary-catheter-associated infections in the elderly

The indwelling urinary catheter is the leading cause of complicated urinary tract infections and Gram-negative bacteraemia in this age group. It accounts for about 40% of life-threatening septicaemia. There is a progressive increase in mortality independently associated with the duration of catheterization. Polymicrobial bacteriuria is common. Urease-producing bacteria lead to encrusted and blocked catheters. The current challenges are to develop effective methods to sensitize healthcare workers to avoid the routine use of indwelling catheters, remove them when no longer needed, develop alternative methods for care of incontinence, employ non-invasive methods to measure urine output, and improve urine drainage systems. The research paradigm needs to focus on prevention of catheter-associated infections rather than on futile attempts to treat irreversible sepsis.
Farnesyltransferase inhibitors and anti-Ras therapy

The oncoprotein encoded by mutantras genes is initially synthesized as a cytoplasmic precursor which requires posttranslational processing to attain biological activity; farnesylation of the cysteine residue present in the CaaX motif located at the carboxy-terminus of all Ras proteins is the critical modification. Once farnesylated and further modified, the mature Ras protein is inserted into the cell's plasma membrane where it participates in the signal transduction pathways that control cell growth and differentiation. The farnesylation reaction that modifies Ras and other cellular proteins having an appropriate CaaX motif is catalyzed by a housekeeping enzyme termed farnesyl-protein transferase (FPTase). Inhibitors of this enzyme have been prepared by several laboratories in an effort to identify compounds that would block Ras-induced cell transformation and thereby function as Ras-specific anticancer agents. A variety of natural products and synthetic organic compounds were found to block farnesylation of Ras proteinsin vitro. Some of these compounds exhibit antiproliferative activity in cell culture, block the morphological alterations associated with Ras-transformation, and can block the growth of Ras-transformed cell lines in tumor colony-forming assays. By contrast, these compounds do not affect the growth or morphology of cells transformed by the Raf or Mos oncoproteins, which do not require farnesylation to achieve biological activity. The efficacy and lack of toxicity observed with FPTase inhibitors in an animal tumor model suggest that specific FPTase inhibitors may be useful for the treatment of some types of cancer.
Evidence for Enterotoxin Production by a Classic Enteropathogenic Serotype of Escherichia coli

Isolates of classic enteropathogenic Escherichia coli O:128 that had been implicated in an outbreak of diarrhea in a hospital nursery were found to produce heat-stable enterotoxin after storage for six years. This finding indicated that enteropathogenicity and the ability to produce enterotoxin may coincide in E. coli, and further study of enteropathogenic strains that produce enterotoxin may help in elucidation of the relationship between enteropathogenic and enterotoxigenic E. coli.
Uncertainty in the determination of fatigue crack facet crystallography

Abstract The uncertainty of facet crystallography measured by stereology and electron backscattered diffraction is less than 3°, based on multiple measurements on an oriented Si single crystal and an Al–Li–Cu alloy fatigue crack. This provides a guideline for the characterization of physically meaningful differences in facet crystallography, which in turn guides damage mechanism assessment.
Macromolecular crystal growth investigations using atomic force microscopy

Direct visualization of macromolecular crystal growth using atomic force microscopy (AFM) has provided a powerful tool in the delineation of mechanisms and the kinetics of the growth process. It has further allowed us to evaluate the wide variety of impurities that are incorporated into crystals of proteins, nucleic acids, and viruses. It is possible, using AFM, to image the defects and imperfections that afflict these crystals, the impurity layers that poison their surfaces, and the consequences of various factors on morphological development. All of these can be recorded under normal growth conditions, in native mother liquors, over time intervals ranging from minutes to days, and at the molecular level.
The artificial dispute over Implicit Personality Theory: An answer to Jackson, Strieker, and Mirels

In their evaluation of Tzeng and Tzeng's (1982) concerns over the level of sophistication currently evident in the study of Implicit Personality Theory (IPT), Jackson and Strieker (1982) and Mirels (1982a) reaffirm their disputed positions at the opposing extremes of the myth-vs.-fact continuum of IPT. The present paper re-examines major measurement and statistical issues in the empirical study of IPT that are still unacknowledged by either Jackson and Strieker, or Mirels, or both. It is demonstrated that their dispute is artificial and can be accounted for by their lack of measuremental sophistication and their statistical partialities. Researchers are cautioned to consider more than “mechanical computability” and “statistical adoptability” in conducting and/or judging similar empirical studies.
Recapitulation of phylogeny by ontogeny in nephrology

Keywords: renal embryology, insulin-like growth factor-I, xenotransplantation, acute renal failure, chronic renal failure
Multichannel Mueller matrix ellipsometer for real-time spectroscopy of anisotropic surfaces and films

A multichannel ellipsometer in the dual-rotating-compensator configuration has been developed for potential applications in real-time Mueller matrix spectroscopy of anisotropic surfaces and films. This instrument provides spectra (1.7-5.3 eV) in all 16 elements of the unnormalized Mueller matrix M of a film-substrate system with a minimum overall data acquisition time of t(a) = 0.25 s. We have applied this instrument first for high-precision determination of spectra in M with t(a) = 2.5 s for a microscopically sculptured film.
Reflection of Neutrons from Magnetized Mirrors

The index of refraction for neutrons in ferromagnetic materials has been studied by total reflection from mirrors. It is shown that Bloch's constant, $C$, is unity; i.e., that the effective field for neutrons in a ferromagnet is B. For the case of total reflection, it is found that the magnetic part of the index is given by the field averaged over a region large compared to the size of the magnetic domains. Completely polarized thermal neutrons have been produced, without the necessity of monochromatization, by reflection from magnetized cobalt. Measurement of the polarization, performed by reflection at a second cobalt mirror, requires careful elimination of reorientation effects in the region between the mirrors.
Two Asymmetric Syntheses of AMG 221, an Inhibitor of 11β-Hydroxysteroid Dehydrogenase Type 1

Two asymmetric syntheses of AMG 221 (2), an inhibitor of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) discovered in our laboratories, are reported. One of the syntheses utilizes chiral trimethylsilyl cyanohydrin 12 as starting material and the other utilizes its enantiomer ent-12. The displacement approach involves the conversion of 12 to 2 via a six-step sequence, occurs with net inversion of configuration, and employs amine 6 as starting material. This route features a novel approach toward chiral dialkylsubstituted α-mercaptoacids. The cyclization approach entails the synthesis of 2 from ent-12 in 2 steps, takes place with net retention of configuration, and uses thiourea 8 as starting material. The final step of this route exemplifies a novel synthesis of chiral C-5 dialkylsubstituted 2-aminothiazolones from chiral α-hydroxyacids and thioureas. Insights into the mechanism of this transformation and study of the effect of the medium on the stereochemical outcome of the reaction are presented.
Spatiotemporal continuous wavelets applied to missile warhead detection and tracking

This paper addresses the problem of tracking a ballistic missile warhead. In this scenario, the ballistic missile is assumed to be fragmented into many pieces. The goal of the algorithm presented here is to track the warhead that is among the fragments. It is assumed that images are acquired from an optical sensor located in the interceptor nose cone. This imagery is used by the algorithm to steer the course of interception. The algorithm proposed in this paper is based on continuous spatio-temporal wavelet transforms (CWTs). Two different energy densities of the CWT are used to perform velocity detection and filtering. Additional post-processing is applied to discriminate among objects traveling at similar velocities. Particular attention is given to achieving robust performance on noisy sensor data and under conditions of temporary occlusions. First we introduce the spatio-temporal CWT and stress the relationships with classical orientation filters. Then we describe the CWT- based algorithm for target tracking, and present results on synthetically generated sequences.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Properties of tryptophanase from Escherichia coli

Abstract A procedure is presented for the purification of tryptophanase from Escherichia coli. The molecular weight is estimated as 490 000 on the basis of sedimentation-equilibrium studies. One molecule of enzyme is estimated to form 19 600 molecules of indole per minute at 37° under appropriate reaction conditions. By a method independent of enzyme activity, tryptophanase was determined to constitute 7·5% of the protein of maximally induced cells. The amino acid composition of tryptophanase shows the enzyme to be less acidic than average E. coli protein.
Cancellative semigroups with non-empty center

Cancellative, idempotent-free semigroups having non-empty center are characterized in terms of a Schreier extension. Cancellative pivoted semigroups with non-empty center are characterized as a group or in terms of a triple (G,H,I), where G is a group, H is either empty or a subgroup of G and I is a function mapping GxG into the non negative integers.
I'll try to accommodate you

A diving, piscivorous bird faces some very special challenges that demand evolutionary creativity. A hunting vertebrate that pursues and captures prey under water must reckon with the loss of corneal refractive power since the cornea has approximately the same index of refraction as water. Hence, such hunters must rely upon lenticular accommodation for the entire dioptric power of the eye under water. But birds face an additional twist compared with predatorial fish. A bird must approximate emmetropia when airborne because its cornea will have refractive power in air as it will have a different index of refraction compared to air. Cormorants and their kin are a model for the successful solution to these problems. Most fish, on the other hand, never face air as a medium and consequently never use their cornea as a refractive surface. The Australian darter ( Anhinga melanogaster ), also known as one of the snakebirds (Anhingidae), seen on the cover is very closely related to cormorants, and allied to pelicans. Snakebirds are …
Feruloyl and p-coumaroyl esterase from anaerobic fungi in relation to plant cell wall degradation

Trans-feruloyl and trans-p-coumaroyl esterases were found in the culture filtrates of two monocentric (Piromyces MC-1, Neocallimastix MC-2) and three polycentric (Orpinomyces PC-2, Orpinomyces PC-3, and PC-1, an unnamed genus with uniflagellated zoospores) isolates of anaerobic rumen fungi. Treatment of cell walls of Coastal bermudagrass shoots with the filtrates released the trans isomers of ferulic and p-coumaric acids; results of microscopic observations indicated that fungal isolates degraded primarily unlignified cell walls in leaf blades and stems. A greater proportion of ferulic than p-coumaric acid was released by this treatment when compared with the amounts of the acids released by saponification of the walls with 1 M NaOH. The filtrates also showed esterase activities against the trans isomers of methyl ferulate and methyl p-coumarate, with ferulic acid being released at a faster rate than p-coumaric acid. Assays for other cell-wall-degrading enzymes (xylanase, β-xylosidase, α-l-arabinosidase, cellulase, β-glucosidase) indicated that only β-xylosidase correlated with ferulate and p-coumarate esterase activities. The monocentric isolate MC-2 had the highest esterase activity against both the plant cell wall and methyl ester substrates and the highest specific activities of acetyl esterase, β-xylosidase, α-l-arabinosidase, cellulase and β-glucosidase. Isolate MC-2 produced substantially greater amounts of feruloyl and p-coumaroyl esterase when the growth substrate contained higher levels of saponifiable ferulic and p-coumaric acids.
Anesthesia for the Obstetric Patient with Multiple Sclerosis

Data on all obstetric patients delivering at the Brigham and Women's Hospital during the years 1982 through 1987 were collected. The anesthetic techniques used, the type and amount of anesthetic agents administered, and the postpartum relapse rate of multiple sclerosis patients were compared. Women who received epidural anesthesia for vaginal delivery did not have a significantly higher incidence of relapse than those who received local infiltration. However, all of the women who experienced postpartum relapses had received concentrations of bupivacaine greater than 0.25%. This finding may suggest that a higher concentration of drug over a longer period of time may adversely influence the relapse rate.
Relationship of vector numbers and age of Corn plants at inoculation to severity of Corn stunt disease.

The relationship of Dalbulus maidis (Delong & Walcott), vector numbers, and corn plant age at inoculation with the corn stunt disease agent (CSA) to disease severity were investigated in a field cage and greenhouse. Plant age at inoculation with the CSA had more effect on corn stunt disease severity than that of leafhopper vector numbers. Plant height was reduced, incubation of the disease agent in the plants was shorter, and yield was less in plants inoculated at each earlier stage of development or with an increase in vector numbers.
Fluid Flow-Related Transport Phenomena in Steel Slab Continuous Casting Strands under Electromagnetic Brake

In the current study, a three-dimensinal (3D) numerical model is built to investigate the effect of a local-type electromagnetic brake (EMBr) on the fluid flow, heat transfer, and inclusion motion in slab continuous casting strands. The results indicate that the magnetic force affects the jet characteristics, including jet angle, turbulent kinetic energy, and its dissipation rate. To reduce the top surface velocity and stabilize the top surface, the magnetic flux intensity should be larger than a critical value. With a 0.39 T magnetic flux intensity, the top surface velocity and its fluctuation can be well controlled, and less slag is entrained. The motion of argon bubbles is also studied. More bubbles, especially >2.0-mm bubbles, escape from the top surface between the mold submerged entry nozzle (SEN) and \( \frac{1}{4} \) width for the case with a 0.39 T EMBr. This may push the top slag away and create an open “eye” on the top slag. Small bubbles (≤1 mm) tend to escape from one side of wide face no matter with or without EMBr, which is induced by the swirl flow from the SEN outport. EMBr has a little effect on the overall removal fraction of inclusions; however, it affects the local distribution of inclusion in the slab. With EMBr, more inclusions accumulate the region just below the surface, thus a worse subsurface quality, whereas the inner quality of the slab is better than that without EMBr. For heat transfer in the mold, the heat flux on the narrow face and the area of possible break-out zones can be reduced by using EMBr. Prevention of bias flow and/or asymmetrical flow in mold by EMBr is also concluded.
The aging of hydrated aluminum oxide thin films

Abstract We report the results of aging on the electrical, structural and moisture-response characteristics of thin hydrated aluminum oxide films. The films, which have the pseudoboehmite structure, are produced by immersion of evaporated aluminum films into hot or boiling water. The sheet resistance, Rs, measured at room temperature using charge-flow-transistor techniques, is an approximately exponential function of dew point. This high sensitivity to moisture may be attributed to physisorbed moisture and the porous morphology of the film. Samples were aged at room temperature in 40% r.h. and in dry ambients. After 30 hours, Rs follows a power-law increase with time over two months. The aging rate decreases substantially for samples stored in dry ambient, suggesting that physisorbed water contributes to the aging rate. Three H2O components are distinguished by infrared spectroscopy coupled with isotope exchange using D2O: ‘physisorbed’ water, ‘chemisorbed’ water and ‘fixed’ water. The chemisorbed water can exchange rapidly with physisorbed water. However, in the absence of physisorbed water, the chemisorbed water does not exchange with ambient. This mechanism may be related to the hysteresis observed in aluminum oxide moisture sensors. After annealing films below 250 °C, the structure of the film is still that of pseudo-boehmite. However, above 250 °C, a gradual transition to alumina is observed.
Self-Assembly of Filopodia-Like Structures on Supported Lipid Bilayers

Filopodia are finger-like protrusive structures, containing actin bundles. By incubating frog egg extracts with supported lipid bilayers containing phosphatidylinositol 4,5 bisphosphate, we have reconstituted the assembly of filopodia-like structures (FLSs). The actin assembles into parallel bundles, and known filopodial components localize to the tip and shaft. The filopodia tip complexes self-organize—they are not templated by preexisting membrane microdomains. The F-BAR domain protein toca-1 recruits N-WASP, followed by the Arp2/3 complex and actin. Elongation proteins, Diaphanous-related formin, VASP, and fascin are recruited subsequently. Although the Arp2/3 complex is required for FLS initiation, it is not essential for elongation, which involves formins. We propose that filopodia form via clustering of Arp2/3 complex activators, self-assembly of filopodial tip complexes on the membrane, and outgrowth of actin bundles.
Action principle and partition function for the gravitational field in black-hole topologies.

Statistical mechanics of gravitational fields describing the black-hole topological sector, and the correspondence to thermodynamics, are considered. The Euclidean action is evaluated on the constraint hypersurface and a measure is obtained, resulting in a path-integral form of the canonical partition function. We obtain the usual black-hole entropy plus quantum corrections when the temperature and size of the system are appropriate. Under other conditions, we give evidence for the existence of a phase transition (change of topology).
Case of Localized Recombination in 23S rRNA Genes from Divergent Bradyrhizobium Lineages Associated with Neotropical Legumes

Enzyme electrophoresis and rRNA sequencing were used to analyze relationships of Bradyrhizobium sp. nodule bacteria from four papilionoid legumes (Clitoria javitensis, Erythrina costaricensis, Rhynchosia pyramidalis, and Desmodium axillare) growing on Barro Colorado Island (BCI), Panama. Bacteria with identical multilocus allele profiles were commonly found in association with two or more legume genera. Among the 16 multilocus genotypes (electrophoretic types [ETs]) detected, six ETs formed a closely related cluster that included isolates from all four legume taxa. Bacteria from two other BCI legumes (Platypodium and Machaerium) sampled in a previous study were also identical to certain ETs in this group. Isolates from different legume genera that had the same ET had identical nucleotide sequences for both a 5′ portion of the 23S rRNA and the nearly full-length 16S rRNA genes. These results suggest that Bradyrhizobium genotypes with low host specificity may be prevalent in this tropical forest. Parsimony analysis of 16S rRNA sequence variation indicated that most isolates were related to Bradyrhizobium japonicum USDA 110, although one ET sampled from C. javitensis had a 16S rRNA gene highly similar to that of Bradyrhizobium elkanii USDA 76. However, this isolate displayed a mosaic structure within the 5′ 23S rRNA region: one 84-bp segment was identical to that of BCI isolate Pe1-3 (a close relative of B. japonicum USDA 110, based on 16S rRNA data), while an adjacent 288-bp segment matched that of B. elkanii USDA 76. This mosaic structure is one of the first observations suggesting recombination in nature between Bradyrhizobium isolates related to B. japonicum versus B. elkanii.
Phase Equilibria in Liquid Crystalline Systems Part I. Synthesis and Liquid Crystalline Properties of Oligomers of the p-Oxybenzoate Series

Syntheses of the trimer (n = 3), tetramer (n = 4) and the pentamer (n = 5) of the p-oxybenzoate series C6H5CO(–OC6H4CO)n-2-OC6H5 are reported. Densities and thermal expansion coefficients of the neat liquids were measured and phase transitions in the pure compounds and their binary mixtures were investigated by differential scanning calorimetry (DSC). The nematic-isotropic transition is directly accessible only in the case of the tetramer (melting point 181°C, nematic-isotropic transition temperature TNI = 254°); the trimer melts to an isotropic liquid at 136°C and the nematic-isotropic transition of the pentamer (melting point 224°C) lies above the range of thermal stability. DSC results for the binary mixtures show the coexistence range of the nematic and the isotropic phases to be very small; it is obscured by pre- and post-transition effects. In satisfactory approximation therefore, the binary mixtures can be treated as one-component systems, and TNI may be identified with the maximum of the DSC peak. Values of TNI thus obtained are linear with respect to composition and may be extrapolated to obtain TNI = 100°C for the pure trimer and 464°C for the pure pentamer. As shown by conformational analysis, all conformers of a given homolog have virtually the same axial ratio. These compounds therefore can be treated as rigid rods.
Critical Race Theory and the Proliferation of U.S. Charter Schools.

Charter schools have substantial bipartisan support for their expansion. Yet, the bulk of charter school research ascertains that the majority of students in charter schools do not significantly outscore their traditional school peers on measurable indicators of academic performance. Additionally, students in charter schools do not have comparable schooling experiences to their middle-class, White peers in affluent urban and suburban schools. Using critical race theory to analyze recent charter school research, we challenge the notion of marketplace theory as a viable reform strategy to create more equitable education, and we suggest that the substantial financial profits associated with charter schools are one reason policymakers continue to ignore the negative outcomes of charter schools and push for the creation of more charter schools.
Role of Sphingosine Kinase 2 in Cell Migration toward Epidermal Growth Factor

Sphingosine 1-phosphate (S1P), produced by two sphingosine kinase isoenzymes, denoted SphK1 and SphK2, is the ligand for a family of five specific G protein-coupled receptors that regulate cytoskeletal rearrangements and cell motility. Whereas many growth factors stimulate SphK1, much less is known of the regulation of SphK2. Here we report that epidermal growth factor (EGF) stimulated SphK2 in HEK 293 cells. This is the first example of an agonist-dependent regulation of SphK2. Chemotaxis of HEK 293 cells toward EGF was inhibited by N,N-dimethylsphingosine, a competitive inhibitor of both SphKs, implicating S1P generation in this process. Down-regulating expression of SphK1 in HEK 293 cells with a specific siRNA abrogated migration toward EGF, whereas decreasing SphK2 expression had no effect. EGF contributes to the invasiveness of human breast cancer cells, and EGF receptor expression is associated with poor prognosis. EGF also stimulated SphK2 in MDA-MB-453 breast cancer cells. Surprisingly, however, down-regulation of SphK2 in these cells completely eliminated migration toward EGF without affecting fibronectin-induced haptotaxis. Our results suggest that SphK2 plays an important role in migration of MDA-MB-453 cells toward EGF.
Linear increase in optimal pedal rate with increased power output in cycle ergometry

This experiment was designed to estimate the optimum pedal rates at various power outputs on the cycle ergometer. Five trained bicycle racers performed five progressive maximal tests on the ergometer. Each rode at pedal rates of 40, 60, 80, 100, and 120 rev X min-1. Oxygen uptake and heart rate were determined from each test and plotted against pedal rate for power outputs of 100, 150, 200, 250, and 300 W. Both VO2 and heart rate differed significantly among pedal rates at equivalent power outputs, the variation following a parabolic curve. The low point in the curve was taken as the optimal pedal rate; i.e., the pedal rate which elicited the lowest heart rate or VO2 for a given power output. When the optimum was plotted against power output the variation was linear. These results indicate that an optimum pedal rate exists in this group of cyclists. This optimum pedal rate increases with power output, and when our study is compared to studies in which elite racers, or non-racers were used, the optimum seems to increase with the skill of the rider.
α-ketoglutarate coordinates carbon and nitrogen utilization via enzyme I inhibition

Microbes survive in a variety of nutrient environments by modulating their intracellular metabolism. Balanced growth requires coordinated uptake of carbon and nitrogen, the primary substrates for biomass production. Yet the mechanisms that balance carbon and nitrogen uptake are poorly understood. We find in Escherichia coli that a sudden increase in nitrogen availability results in an almost immediate increase in glucose uptake. The concentrations of glycolytic intermediates and known regulators, however, remain homeostatic. Instead, we find that α-ketoglutarate, which accumulates in nitrogen limitation, directly blocks glucose uptake by inhibiting enzyme I, the first step of the sugar-phosphoenolpyruvate phosphotransferase system (PTS). This inhibition enables rapid modulation of glycolytic flux without marked changes in the concentrations of glycolytic intermediates by simultaneously altering import of glucose and consumption of the terminal glycolytic intermediate phosphoenolpyruvate. Quantitative modeling shows that this previously unidentified regulatory connection is, in principle, sufficient to coordinate carbon and nitrogen utilization.
Efficacy and safety of St. John's wort for the treatment of major depression.

Objective Extracts of St. John's wort have been widely used in the treatment of depression. Our aim was to review information related to the efficacy and safety of St. John's wort as an antidepressant. Data sources Primary and review articles were identified by a search of Medline (1960 to February 2000) and through secondary sources. Study selection All the articles identified from the data sources were evaluated and all relevant information was included in this review. The pharmacokinetics, mechanism of action, efficacy, side effects and drug interactions of St. John's wort have been examined in various studies. Conclusion St. John's wort is a promising investigational antidepressant, but the data are not yet sufficient to accept hypericum as a first line antidepressant preparation for treatment of depression. Besides the need for dose standardization and adequate trial lengths, there is a need for studies in severely depressed patients and long-term studies to assess the risk of relapse and recurrence.
Knowledge Exchange Mechanisms and Innovation Policy in Post-Industrial Regions: Approaches of the Basque Country and the West Midlands

Many countries and regions struggle with utilization of knowledge assets and they developed over the years research and innovation infrastructure to enhance innovation in the private sector. The objective of this study is to review the innovation policy initiatives promoting innovation and cooperation between the regional knowledge base and private sector based on the experience of post-industrial regions of the Basque Country and the West Midlands characterized by similar economic history and challenges in regaining competitiveness. In addition to the mechanisms promoting innovation and knowledge exchange, the study presents the regions’ economic background, innovation performance, and institutional framework of innovation policy. The article ends with conclusions and policy implications for other regions.
Collaboration in Building a Global Archive: Vision, practice, methodology, and analysis

We welcome readers to the initial issue of JWHI. The journal is part of a broader mission to promote the collection, publication, review, and analysis of world-historical data. It focuses on collaborative discussion across numerous disciplines, in order to bring together the best scholarly minds in the creation of Big Data in history. Its audience is to include scholars and practitioners in every field of history and social sciences, in information science, in the humanities and natural sciences.
Antiviral activity of oxidized polyamines and aldehydes

Abstract Amine oxidase was isolated from lamb serum, purified 50-fold by Chromatographic techniques, and used in the preparation of the aminoaldehydes of spermine and spermidine. Crude spermine aldehyde inactivated a number of animal viruses, but failed to affect virus hemagglutination. Chromatographic fractionation of the aldehyde of spermidine or spermine indicated that fractions containing peak amine aldehyde concentrations produced maximal inactivation of vesicular stomatitis virus. Inactivation of vesicular stomatitis virus by column-purified oxidized spermidine (a monoaldehyde) or spermine (a dialdehyde) was a function of the concentration of aldehydic groups. Viral inactivation produced by the amine aldehydes proceeds in a linear-first-order reaction with respect to time. Studies to determine structure-antiviral activity relationships were conducted with a number of aliphatic and aromatic aldehydes. These results suggest that the aldehyde moiety is the primary determinant of antiviral activity.
The theory of trying and goal-directed behavior: The effect of moving up the hierarchy of goals

This article extends the literature regarding goal-directed behavior as modeled by the theory of trying by incorporating the concept of the hierarchy of goals. Individuals develop “programs” intended to implement their principles and life goals. Within these programs, goals are arranged in a hierarchical order depending on how close they are to the overall goal of the program. Lower-level goals are intended to set the stage for the achievement of higher-level goals. Although most tests of the theory of trying have been implemented with the use of fairly low-level goals (losing weight or learning a new piece of software), in this article, the model is applied in the context of a higher-level goal: achieving a college education. There are important differences in the results compared to those in prior tests of the theory of trying. Most importantly, attitude toward failure is highly significant and attitude toward process is not. © 2003 Wiley Periodicals, Inc.
Effects of local constraints on the convergence behavior of sequential modular simulators

Abstract The convergence behavior of sequential modular simulators was studied. With local constraints, the well-known tearing algorithm by Upadhye and Grens (AIChE Jl 21, 137, 1975) was found to be unable to distinguish between good and bad tear sets. A nonlinear equation solver, Broyden's method, the traditional control block approach and an optimizer which is a hybrid of infeasible and feasible strategies for optimization were used in the simulation of constrained flowsheets. The convergence behavior of constrained flowsheets is quite different from that of unconstrained flowsheets.
A brief history of NTP time: memoirs of an Internet timekeeper

This paper traces the origins and evolution of the Network Time Protocol (NTP) over two decades of continuous operation. The technology has been continuously improved from hundreds of milliseconds in the rowdy Internet of the early 1980s to tens of nanoseconds in the Internet of the new century. It includes a blend of history lessons, technology milestones and series of experiments that shape, define and record the early history of the Internet and NTP.This narrative is decidedly personal, since the job description for an Internet timekeeper is highly individualized and invites very few applicants. There is no attempt here to present a comprehensive tutorial, only a almanac of personal observations, eclectic minutiae and fireside chat. Many souls have contributed to the technology, some of which are individually acknowledged in this paper, the rest too numerous left to write their own memoirs.
Predicting Microwave Digital Signal Integrity

High-speed digital signal integrity at data rates above 6 Gb/s is an obstacle to reliable serial link operation. Two signal integrity challenges include dispersion due to frequency-dependent losses and reflections created at impedance mismatches. Signal integrity analysis relies on time-domain simulation of pseudo-random data patterns. This paper explores a predictive method for interconnect eye closure caused by reflections at the transmitter and receiver and does not require extensive time domain simulation. Worst-case bounds on intersymbol interference and data-dependent jitter aid prediction for link budgets under channel variations. This method is applied to the design of a passive equalizer.
Radiosensitization of mammary carcinoma cells by telomere homolog oligonucleotide pretreatment.

Ionizing radiation (IR) is a widely used approach to cancer therapy, ranking second only to surgery in rate of utilization. Responses of cancer patients to radiotherapy depend in part on the intrinsic radiosensitivity of the tumor cells. Thus, promoting tumor cell sensitivity to IR could significantly enhance the treatment outcome and quality of life for patients. Mammary tumor cells were treated by a 16-base phosphodiester-linked oligonucleotide homologous to the telomere G-rich sequence TTAGGG (T-oligo: GGTTAGGTGTAGGTTT) or a control-oligo (the partial complement, TAACCCTAACCCTAAC) followed by IR. The inhibition of tumor cell growth in vitro was assessed by cell counting and clonogenic cell survival assay. The tumorigenesis of tumor cells after various treatments was measured by tumor growth in mice. The mechanism underlying the radiosensitization by T-oligo was explored by immunofluorescent determination of phosphorylated histone H2AX (γH2AX) foci, β-galactosidase staining, comet and Terminal deoxynucleotidyl transferase dUTP Nick End Labeling (TUNEL) assays. The efficacy of the combined treatment was assessed in a spontaneous murine mammary tumor model. Pretreatment of tumor cells with T-oligo for 24 hours in vitro enhanced both senescence and apoptosis of irradiated tumor cells and reduced clonogenic potential. Radiosensitization by T-oligo was associated with increased formation and/or delayed resolution of γH2AX DNA damage foci and fragmented DNA. T-oligo also caused radiosensitization in two in vivo mammary tumor models. Indeed, combined T-oligo and IR-treatment in vivo led to a substantial reduction in tumor growth. Of further significance, treatment with T-oligo and IR led to synergistic inhibition of the growth of spontaneous mammary carcinomas. Despite these profound antitumor properties, T-oligo and IR caused no detectable side effects under our experimental conditions. Pretreatment with T-oligo sensitizes mammary tumor cells to radiation in both in vitro and in vivo settings with minimal or no normal tissue side effects.