cssi/SciSciGPT-SciSciNet huggingface dataset:
Hydrodynamic dispersion in rotating-disk omvpe reactors: Numerical simulation and experimental measurements

Abstract The gas flow pattern in an OMVPE reactor controls the extent of non-uniformity in epilayer thickness and composition and of compositional grading between interfaces in heterostructures grown by switching of the inlet gas composition. Numerical simulation of flow and concentration fields and measurements of tracer gas composition are used to analyze the effects of operating parameters on epilayer growth in a vertical rotating-disk OMVPE reactor. Finite element calculations of flow and temperature fields predict a regime in terms of reactor pressure, flow rate and susceptor rotation rate for operating without the formation of secondary flow circulations. The presence of multiple steady-state flow configurations and flow hysteresis with changing operating conditions are predicted. Analysis of steady-state and transient species transport of the reactant species shows that radial non-uniformities and diffuse interfaces result from secondary cells. The calculations are partially verified by experimental measurements of the response of the composition above the susceptor to step changes in the inlet composition. For an operating pressure of 0.2 atm, mass flow rate of 10 SLMP, and susceptor rotation rate of 500 rpm, calculations predict a flow free of secondary cells and heterostructures with radial uniformity of 2% and interface widths of 1–2 monolayers. Preliminary experiments on the growth of GaAs/AlGaAs epilayers are consistent with these predictions.
Conductive Block Copolymers Integrated into Polynorbornene-Derived Scaffolds

The synthesis and electrochemical properties of novel block copolymers are reported. Three different norbornene derivatives having phenylene−thiophene, phenylene−bithiophene, and phenylene−furan structures were copolymerized with either norbornene or 7-oxanorbornene derivatives via ring-opening metathesis polymerization (ROMP). Block copolymers’ stabilities and solubilities could be improved by hydrogenation of double bonds in the polymer backbone. The block copolymers were subsequently cross-linked by anodic electropolymerization of phenylene−heterocycle moieties, affording conducting polymers. All of these three block copolymers were readily deposited on the electrode substrates, and their cyclic voltammograms (CVs) revealed an excellent reversibility in the redox cycles.
Fertility and Longevity: A Soviet Interpretation:

Demographers in the United States as in the Soviet Union have explored the possibility that a positive association exists between the fertility of women and their longevity. Most Soviet researchers are convinced there is empirical evidence to support the hypothesis but their counterparts in the United States are less sanguine. The interrelationship between sex, fertility, good health and long life have intrigued philosophers, statisticians, physiologists and gerontologists and they have spawned a great variety of explanations.
Oleanene constituents of Lantana cujabensis.

A new compound, 3β,25-epoxy-3α-hydroxy-22β-isobutanoyloxyolean-12-ene-28-oic acid (1), and two known triterpenoids lantanilic acid (2) and camaric acid (3) were isolated from the stem and leaves of Lantana cujabensis. Their structures were elucidated by spectroscopic methods. The ethanol extracts did not show significant in vitro antiplasmodial activity against chloroquine-sensitive or resistant strains of Plasmodium falciparum.
A familial mutation renders atrial natriuretic peptide resistant to proteolytic degradation

A heterozygous frameshift mutation causing a 12-amino acid extension to the C terminus of atrial natriuretic peptide (ANP) was recently genetically linked to patients with familial atrial fibrillation (Hodgson-Zingman, D. M., Karst, M. L., Zingman, L. V., Heublein, D. M., Darbar, D., Herron, K. J., Ballew, J. D., de Andrade, M., Burnett, J. C., Jr., and Olson, T. M. (2008) N. Engl. J. Med. 359, 158–165). The frameshift product (fsANP), but not wild-type ANP (wtANP), was elevated in the serum of affected patients, but the molecular basis for the elevated peptide concentrations was not determined. Here, we measured the ability of fsANP to interact with natriuretic peptide receptors and to be proteolytically degraded. fsANP and wtANP bound and activated human NPR-A and NPR-C similarly, whereas fsANP had a slightly increased efficacy for human NPR-B. Proteolytic susceptibility was addressed with novel bioassays that measure the time required for kidney membranes or purified neutral endopeptidase to abolish ANP-dependent activation of NPR-A. The half-life of fsANP was markedly greater than that of wtANP in both assays. Additional membrane proteolysis studies indicated that wtANP and fsANP are preferentially degraded by neutral endopeptidase and serine peptidases, respectively. These data indicate that the familial ANP mutation associated with atrial fibrillation has only minor effects on natriuretic peptide receptor interactions but markedly modifies peptide proteolysis.
Ventilator Y-piece pressure compared with intratracheal airway pressure in healthy intubated children.

Objective. Compare airway pressure measurements at the ventilator Y-piece of the breathing circuit (P Y ) to intratracheal pressure measured at the distal end (P T ) of the endotracheal tube (ETT) during mechanical ventilation and spontaneous breathing of intubated children. Methods. Thirty children (age range 29 days to 5 years) receiving general anesthesia were intubated with an ETT incorporating a lumen embedded in its sidewall that opened at the distal end to measure P T . Peak inflation pressure (PIP) was measured at P Y and P T during positive pressure ventilation. Just before extubation, all measurements were repeated and imposed resistive work of breathing (WOBi) was calculated at both sites while breathing spontaneously. Results. Average PIP was approximately 25% greater at P Y (19.7 ± 3.4 cm H2O) vs. P T (15.0 ± 2.9 cm H2O), p < 0.01. During spontaneous inhalation P T was 59% lower ({bond}8.5 ± 4.0 cm H2O) vs. P Y ({bond}3.5 ± 2.0 cm H2O), p < 0.01. WOBi measured at P Y (0.10 ± 0.02 Joule/L) was 86% less than WOBi measured at P T (0.70 ± 0.40 Joule/L), p < 0.01. Conclusions. In healthy children P Y significantly overestimates PIP in the trachea during positive pressure ventilation and underestimates the intratracheal airway pressure during spontaneous inhalation. During positive pressure ventilation P T better assesses the pressure generated in the airways and lungs compared to P Y because P T also includes the difference in airway pressure across the ETT tube due to resistance. During spontaneous inhalation, P T reflects the series resistance of the ETT and ventilator circuit, while P Y reflects only the resistance of the ventilator circuit, accounting for the smaller decreases in pressure. Additionally, P Y underestimates the total WOBi load on the respiratory muscles. Thus, P T is a more accurate reflection of pulmonary airway pressures than P Y and suggests that it should be incorporated into ventilator systems to more accurately trigger the ventilator and to reduce work of breathing.
Enhancement of the Morphology and Open Circuit Voltage in Bilayer Polymer/Fullerene Solar Cells

We describe the influence of thermal annealing on the performance of polymer bilayer solar cell devices of regioregular poly(3-hexylthiophene), regiorandom poly(3-hexylthiophene), or poly(3-hexyl-2...
Feulgen Reaction for Thymonucleic Acid

The importance of thymonucleic acid in tissues is discussed briefly. The technic of the Feulgen reaction which has been employed in photometric histochemical observations in tumors is described. The evidence for the specificity of the Feulgen reaction is reviewed and additional experimental observations are reported. The staining of tissues by the Feulgen reaction is compared with that of hematoxylin, basic fuchsia, and fuchsin-sulfurous-acid reagent in which the color had been developed by the addition of formaldehyde. The stains were compared with respect to (1) the selective staining of the cytologic components of the tissues, (2) the staining of tissues following varying intervals of acid hydrolysis and (3) the photometric determination of the fading of the stained tissue by a carbon arc light. The photometric apparatus employed is suitable for the study of many problems on the staining of tissues. Staining by the Feulgen reaction is different from that of both the basic fuchsin from which the fuchsin...
A process-based model of ammonia emissions from dairy cows: improved temporal and spatial resolution

This research has developed an integrated model of a dairy farm that predicts monthly ammonia emission factors based on farming practices and climate conditions, including temperature, wind speed, and precipitation. The model can be used to predict the seasonal and geographic variations in ammonia emission factors, which are important for accurately predicting aerosol nitrate concentrations. The model tracks the volume of manure and mass of ammoniacal nitrogen as the manure moves through the housing, storage, application, and grazing stages of a dairy farm. Most of the processes of ammonia volatilization are modeled explicitly, but poorly understood processes are parameterized and tuned to match empirical data. The tuned model has been compared to independent experimental data and is shown to be robust over the range of experimental conditions. We have characterized the differences in emissions resulting from changes in climate conditions and farming practices and found that both of these factors are significant and should be included when developing a national inventory.
177 PREDICTION OF MORPHINE DEPENDENCY IN ENDOTRACHEALLY INTUBATED CHILDREN

Endotracheally intubated (EI) children usually require some combination of sedative (i.e., morphine) and paralyzing (i.e., pancuronium) medications. The potential for inducing physiological drug dependency in such children should increase in proportion to both the dosage and duration of sedation. A retrospective review of 13 admissions to a multidisciplinary pediatric ICU who are EI ≥ 9 days revealed a progressive increase in morphine requirement on a stable pancuronium dosage. Ten children received 16mg/kg cumulative morphine dosage over several subsequent weeks of EI. The remaining three children received >16mg/kg cumulative morphine dosage and each showed signs of dependency. Our conclusion is that cumulative morphine dosage may help to identify EI children at risk of withdrawal.
Particle acceleration at CME driven shock waves

Abstract A dynamical time-dependent model of particle acceleration at coronal mass ejection (CME) driven shock waves is presented. We consider first a one-dimensional model applicable to shock waves of arbitrary strength. The model includes the determination of the particle's injection energy, the maximum energy of particles accelerated at the shock, energetic particle spectra at all spatial and temporal locations, and the dynamical distribution of particles that are trapped in the post shock flow and those that escape upstream and downstream of the evolving shock complex. We then consider the extension of this model to two dimensions. The 2-dimensional model computes the variation of the shock strength both temporally and spatially and illustrates how this effects the evolution of the energetic particle spectra and intensities.
Mathematics Of Spectral Treatment In The Fourier Domain

The basic premise of Fourier domain processing is that the Fourier transform does not alter the information content of a spectrum. Spectra have traditionally been recorded in the frequency, wavelength or wavenumber domain, and this is referred to as the spectral domain. The Fourier transform of a spectrum converts the data to the time, wavenumber or retardation domain, known as the Fourier domain. Data manipilation is often carried out in the Fourier domain, particularly Fourier self-deconvolution, smoothing, and differentiation. These operations involve convolution in the spectral domain, which is equivalent to a multiplication in the Fourier domain. It is mathematically less expensive to achieve these operations in the Fourier domain. Other data handling operations can be achieved in the Fourier domain. The first of these is the Gram-Schmidt orthogonalization of raw GC/FT-IR spectrometry interferograms to construct infrared-based chromatograms. Search systems and structure elucidation methods can also be effectively carried out using Fourier transforms of absorption spectra.
Crystal electric fields in heavy-electron metals: The specific heats of U 2 Zn 17 and CeCu 6 to 70 K

Two temperature scales--(1) ${T}_{0}$ (single impurity) and/or ${T}_{F}^{\mathrm{*}}$ (degenerate Fermi) and (2) crystal-electric-field splitting(s) \ensuremath{\Delta}--provide the basis for dividing the excitation spectra of heavy-electron systems into three regimes. They are (i) for ${T}_{0}$, the specific heat and susceptibility are that due to independent f atoms in a crystal field; (ii) for T\ensuremath{\sim}${T}_{0}$, a bump appears in the specific heat due to the Kondo compensation; (iii) for T${T}_{0}$, interaction effects between the f atoms lead to a Fermi-liquid solid where band-structure effects show up in the low-temperature properties (T${T}_{F}^{\mathrm{*}}$/100). This paper is primarily concerned with region (i). In particular, we present new specific-heat data for ${\mathrm{U}}_{2}$${\mathrm{Zn}}_{17}$ up to 70 K and ${\mathrm{CeCu}}_{6}$ to 80 K. In comparing these data with those for other heavy-electron materials we conclude that the specific heat for Tg${T}_{0}$ is qualitatively consistent with the existence of crystal-electric-field levels, but that the overall experimental entropy is too high. We present a tentative model to account for this discrepancy through the use of Fermi statistics to describe transitions in a stylized band model with two peaks. Crystal-field levels in most cases have not been confirmed by neutron scattering.
The Council for Agricultural Science and Technology

Abstract The Council for Agricultural Science and Technology has made considerable progress in the past year in all of its focus areas that affect visibility and financial well-being as we strive to achieve our mission. “Building Our Brand” is at the core of every activity, including our product (publications), our member involvement (stakeholder contacts and reports), and our distribution and sales (expanding our reach and affecting the key audiences listed in our mission statement). “Ahead of the Need” information is what the Poultry Science Association can provide us. We are increasing the number of commentary papers that we will produce annually, and we have improved our reach to state and federal congressional contacts and media personnel. We appreciate the support and suggestions of the Poultry Science Association and look forward to continued success in communicating science to society.
Modulation of 32Pi incorporation into phospholipids of polymorphonuclear leukocytes by ionophore A23187

Abstract The effects of ionophore A23187 on the incorporation of 32 P i into phospholipids and on 45 Ca 2+ uptake and release by polymorphonuclear leukocytes were examined. A23187 increased 32 P i incorporation into phosphatidic acid, phosphatidylglycerol, phosphatidylserine, and the phosphoinositides. It also promoted a rapid burst uptake and release of 45 Ca 2+ by leukocytes. External Ca 2+ , but not Mg 2+ , was required for full stimulation of 35 P i incorporation into phosphatidic acid and the phosphoinositides. In the absence of external Ca 2+ the increased radiophosphorus activity of phosphatidic acid, phosphatidylserine and the phosphoinositides was grossly reduced but not eliminated, and the decreased radiophosphorus activity of phosphatidylcholine became pronounced. In addition, the ionophore effect on 32 P i incorporation into leukocyte phospholipids was not abolished by ethyleneglycol bis(β-amino-ethylether)- N , N '-tetraacetic acid. ATP radiophosphorus activity was also enhanced by the presence of A23187, but the enhancement was much less than that of the acidic phospholipids. Based on these findings, it is suggested that the increased 32 P i incorporation into the acidic phospholipids of leukocytes induced by A23187 was not solely derived from the higher radioactivity of ATP, increased Ca 2+ fluxes and perturbation of cellular Ca 2+ distribution of leukocytes exposed to A 23187 may trigger part of the altered 32 P i incorporation into phospholipids.
Oceanography and oil deposits

I think we all feel a certain amount of satisfaction whenever a practical application of a science is found. In work on a project endowed by John D. Rockefeller and carried out under the auspices of the American Petroleum Institute, the science of oceanography is being called upon to aid the oil industry. The purpose of this project is to study the conditions under which the sediments that in the future will be possible source-beds of petroleum are forming today. The work relates to the solution of the question of the origin of petroleum and should afford essential information that will aid the geologist in his increasingly more difficult task of finding new oil-pools.
Discovery of Rapid Hard X-Ray Variability and New Jet Activity in the Symbiotic Binary R Aquarii

Two Chandra observations of the R Aqr symbiotic binary system taken 3.3 yr apart show dramatic changes in the X-ray morphology and spectral characteristics in the inner 500 AU of this system. The morphology of the soft X-ray emission has evolved from a nearly circular region centered on the binary system to an hourglass shape that indicates the formation of a new southwest jet. Synchrotron radiation from the new jet in contemporaneous VLA radio spectra implies the physical conditions in the early stages of jet development are different from those in the more extended outer thermal jets known to exist for decades in this system. The central binary source has two X-ray spectral components in each of the two epochs, a soft component and a highly absorbed hard component characterized by T ~ 108 K if fit with a thermal plasma model. The spectrum hardened considerably between 2000.7 and 2004.0, primarily due to increased flux above 5 keV, suggesting a change in the accretion activity of the white dwarf on a timescale of a few years or less. Point-source Fe K emission is detected at the position of the central binary system in both observations. While the earlier observation shows evidence of only a single emission peak near Fe Kα at 6.4 keV, the later observation shows a more complex emission structure between 6 and 7 keV. Finally, we have discovered a modulation in the hard X-ray flux with a period of 1734 s at a 95% confidence level in the 2004 observation only. The modulation potentially arises from standing shocks in an accretion column, and we have explored the possibility that the white dwarf in R Aqr is analogous to the magnetic white dwarfs in Intermediate Polars.
Enhanced depth imaging optical coherence tomography of the choroid in highly myopic eyes.

Purpose To measure macular choroidal thickness (CT) in highly myopic eyes using enhanced depth imaging optical coherence tomography (OCT). Design Retrospective, observational case series. Methods Enhanced depth imaging OCT images were obtained in highly myopic eyes (≥6 diopters [D]). Images of CT were obtained by positioning a spectral-domain OCT device close enough to the eye to acquire an inverted image. CT was measured from the outer border of the retinal pigment epithelium to the inner scleral border at 1000-μm intervals of a horizontal section from 3 mm temporal to the fovea to 3 mm nasal to the fovea. Statistical analysis was performed to evaluate CT at each location and to correlate CT with age and refractive error. Results The mean age of the 31 patients (55 eyes) was 59.7 years (± 17.6 years; range, 24 to 90 years), and the mean refractive error was −11.9 D (± 3.7 D). The mean subfoveal CT was 93.2 μm (± 62.5 μm) and was correlated negatively with age ( P = .006), refractive error ( P P = .013). Regression analysis suggested that subfoveal CT decreased by 12.7 μm for each decade of life and by 8.7 μm for each D of myopia. Conclusions The choroid in highly myopic eyes is very thin and undergoes further thinning with increasing age and degree of myopia. Abnormalities of the choroid may play a role in the pathogenesis of myopic degeneration.
4KX4K detectors for astronomy

Large format imaging detectors are required in many modern astronomical optical systems. With the increase in aperture size of large telescopes, the associated cameras for imaging and spectroscopy are much larger than those of a decade ago. Large physical format detectors are required to make full use of these cameras. The detector of choice has been the charge coupled devices (CCDs), although large format 4kx4k CMOS imagers have also been fabricated. We discuss recent developments in 4kx4k pixel imagers, typically with 15 micron pixels, which are over 60 mm per side. Several companies have produced such devices with the characteristics required for astronomy. Backside processing issues are discussed, including results from optimization efforts at the University of Arizona Imaging Technology Laboratory. We also discuss the use of such imagers in the 8kx8k 90Prime prime focus mosaic camera now in operation at the Steward Observatory 2.3 m telescope.
AN EXAMINATION OF MERGER SYNERGISM

The empirical research discussed in this paper measures the synergistic effects of mergers on the stockholders of the acquiring and acquired firms. Synergism is defined as the incremental wealth to the shareholders of both merging firms due to the merger—net of any potential gains achievable through investors' personal diversification over the common stocks of the merging firms. Three types of mergers are identified and studied—nonconglomerate, conglomerate with increasing financial leverage, and conglomerate with decreasing financial leverage. The results indicate that these types of mergers are affected differently by the combination. Moreover, the evidence suggests operational and/or financial synergism.
SOLVENT EFFECTS ON THE SPECTRA OF RETINAL SCHIFF BASES—11. MODELS FOR CONVERGENCE AND CLUSTERING OF VISUAL PIGMENT SPECTRA*

— Electronic absorption spectra of retinal (A,) and 3-dehydroretinal (A2) Schiff bases have been studied under a variety of solvent conditions. The spectra of the two species have different solvent dependencies. Variation in solvent conditions have a larger effect in the A2 spectra, although the wavelength maxima of A, and A, Schiff bases smoothly converge in solvents that shift them both to shorter wavelengths. Convergence curves for the A, and A2 Schiff bases can thus be generated in solution which resemble the convergence curves observed in visual pigments. It is also shown that the spectra of visual pigments made by combining A, and A2 with opsins from various fish species can be reproduced theoretically by changing the number of tryptophan or tyrosine side chains which are assumed to line the chromophore pocket. Discrete changes in the number of these side chains can exactly reproduce the clustering effect observed for a large variety of fish visual pigments. Variations in solvent characteristics which are analogous to possible chromophore environments in visual pigments have thus been shown to effect Schiff base spectra in such a way as to mimic the bathochromic shift, spectral convergence, and spectral clustering phenomena exhibited by visual pigments.
Comparison of Early and Six Month Outcomes of Direct Stenting vs. Conventional Stenting in Patients with Angina Pectoris

Background and Objectives:Direct stenting (DS) has been shown to be safe and feasible, with demonstrable reductions in cost, procedural time and radiation exposure, and may also result in less vessel injury. The aim of this study was to compare the immediate and six month clinical and angiographic outcomes of direct stent (DS) with stent implantation implantation following balloon predilatation (conventional stenting, CS). Subjects and Methods:Between July 2001 and June 2004, 266 patients (293 lesions) with angina pectoris were included in this study. Patients having lesion characteristics with excessive calcification, left main lesion, chronic total occlusion, severe proximal tortuosity and a bifurcated lesion were excluded. Follow up angiography was performed about six months after the initial procedure. Results:Direct (73 lesions) and conventional stenting (220 lesions) were performed respectively. In the DS group, the minimal luminal diameter was larger (0.36±0.18 vs. 0.31±0.19 mm, p=0.036) and diameter stenosis lower than in the CS group (89.1±5.1 vs. 90.6±3.9%, p=0.026). However, no difference was found in the reference vessel diameter between the two groups. From the immediate angiographic results, the CS group showed a longer stent length than the DS group (18.84±5.61 vs. 16.16±3.67 mm, p=0.000), but the DS group had a higher balloon inflation pressure than the CS group (12.25±1.71 vs. 11.35±1.72 atm, p= 0.000). However, no difference was found in the post-stent minimal luminal diameter, acute gain and angiographic success rates. Follow up angiography was performed in 68.6% (201/293) of lesions. The angiographic restenosis rate was similar between the two groups (DS, 19.6 vs. CS, 19.3%, p=0.966), as were the other angiographic findings. The rates of in-hospital and 6 month follow up major adverse cardiovascular events (MACE) were similar between the two groups. Conclusion:Direct stenting showed similar rates of angiographic restenosis as well as inhospital and 6 months MACE (death, myocardial infarction, target lesion revascularization, cerebrovascular accident) compared with conventional stenting. (Korean Circulation J 2006;36:214-220)
Some Observations Of The Effects Of Partial Coherence On Projection System Imagery

Partially coherent illumination significantly affects projection system performance. Our theoretical and experimental results cover a variety of test objects imaged with different projection system assemblies, including some nonuniform sources, and show that improved optical lithography performance can be realized.
Interdiffusion and Phase Behavior in Polysynthetically Twinned (PST) TiAl / Ti Diffusion Couples

Diffusion couples of pure Ti and polysynthetically twinned (PST) TiAl (49.3 at.% Al) were prepared by high vacuum hot-pressing, with the bonding interface perpendicular to the lamellar planes. Diffusion experiments were carried out by annealing the couples in the same furnace at 650, 700 and 850oC for various times. The cross-section of the couple was studied using scanning electron microscopy (SEM) and quantitative wavelength-dispersive x-ray spectroscopy (WDS). A reaction layer whose composition is close to that of the stoichiometric α2–Ti3Al phase formed along the PST TiAl / Ti bonding interface in PST TiAl side. Direct measurements of the thickness of the reaction zone were performed at different phase regions and various boundaries. By assuming the thickness of the reaction zone increases as (Dt)1/2, where D is the diffusion coefficient and t is the annealing time, the diffusion coefficients at these temperatures were calculated. Composition profiles in the reaction zone, along the lamellae and at the lamellar interfaces were obtained by WDS analyses. Comments Copyright Materials Research Society. Reprinted from MRS Proceedings Volume 646. 2000 Fall Meeting Symposium N High-Temperature Ordered Intermetallic Alloys IX Publisher URL: http://www.mrs.org/members/proceedings/fall2000/n/N5_53.pdf This conference paper is available at ScholarlyCommons: http://repository.upenn.edu/mse_papers/15 Interdiffusion and Phase Behavior in Polysynthetically Twinned (PST) TiAl / Ti Diffusion Couples Ling Pan, David E. Luzzi Department of Materials Science and Engineering, University of Pennsylvania 3231 Walnut Street, Philadelphia, PA 19104, U.S.A
Reactions to withdrawal symptoms and success in smoking cessation clinics.

Abstract This study reports on 285 smokers in cessation clinics who answered self-report measures of withdrawal symptoms and craving after quitting cigarettes “cold turkey.” Almost all the subjects reported discomfort after stopping, but no particular symptom pattern emerged. Women reporting intense withdrawal symptoms and craving were less likely to remain stopped by the clinic's end. Although men were generally heavier smokers and reported as many symptoms as women, withdrawal distress was not related to their clinic outcomes. This sex difference may be explained by cultural learning which teaches men to be stoic in bearing discomfort and women to avoid small doses to pain.
Effects of hormones on RNA and protein synthesis in the imaginal wing disks of the Ricini silkworm.

Abstract the present study examines the capacity of larval and pharate pupal wing disks of Samia cynthia ricini to synthesize RNA and proteins and the relation of these syntheses to endogenous and injected juvenile hormone and ecdysone during metamorphosis. The dry weight of the wing disks was found to increase in a linear fashion whereas RNA and protein synthesis showed cyclical patterns. Depending on the stage of development, injection of hormones and their analogues induced changes in the synthetic capacities of the wing disks. An injected hormone had its greatest effect when its endogenous level was lowest and vice versa. At no time were the endogenous titres of juvenile hormone and ecdysone simultaneously high. An antagonistic behaviour was observed when a mixture of two hormones was injected. Although the wing disks do not undergo apolysis and are relieved of the responsibility to synthesize cuticle, their metabolism is affected by injection of the ecdysone. This result suggests a possible role for ecdysone besides the induction of moulting.
What a Difference a Bond Makes: The Structural, Chemical, and Physical Properties of Methyl-Terminated Si(111) Surfaces

ConspectusThe chemical, electronic, and structural properties of surfaces are affected by the chemical termination of the surface. Two-step halogenation/alkylation of silicon provides a scalable, wet-chemical method for grafting molecules onto the silicon surface. Unlike other commonly studied wet-chemical methods of surface modification, such as self-assembly of monolayers on metals or hydrosilylation on silicon, the two-step method enables attachment of small alkyl chains, even methyl groups, to a silicon surface with high surface coverage and homogeneity. The methyl-terminated Si(111) surface, by comparison to hydrogen-terminated Si(111), offers a unique opportunity to study the effects of the first surface bond connecting the overlayer to the surface. This Account describes studies of methyl-terminated Si(111), which have shown that the H–Si(111) and CH3–Si(111) surfaces are structurally nearly identical, yet impart significantly different chemical and electronic properties to the resulting Si surface...
Shake-Table Studies of a Four-Span Reinforced Concrete Bridge

AbstractShake-table response of a 33.6-m-long (110-ft-long), four-span, RC bridge model with a continuous posttensioned superstructure supported on three, two-column bents was studied under horizontal bidirectional coherent simulated earthquakes. The pier heights varied, introducing a slight asymmetry about the centerline of the bridge model. The superstructure ends were supported on seat-type abutments that were connected to hydraulic actuators simulating abutment movements. The skew angle was zero. The bridge model was subjected to successive motions simulating a modified version of a record from the 1994 Northridge Earthquake. Results showed that damage was concentrated in plastic hinge regions of the columns and that the pier caps and the superstructure remained essentially elastic. The shortest pier failed, but this pier continued to carry vertical loads, and the bridge did not collapse. Despite the lack of skew, the superstructure-abutment interaction led to large in-plane rotations that caused sign...
Cerebropulmonary dysgenetic syndrome

Ventilatory treatment of neonatal respiratory distress often results in bronchopulmonary dysplasia from congenital surfactant deficiency due to mutants of transporter protein ABCA3. Association of this condition with other severe disorders in premature newborns has not heretofore been reported. A neonatal autopsy included an in vivo whole blood sample for genetic testing. Autopsy revealed severe interstitial pulmonary fibrosis at age 8 days with heterozygotic mutation p.E292V of ABCA3 and severe dystrophic retardation of cerebral cortex and cerebellum. Subsequently, 1300 archival neonatal autopsies, 1983-2006, were reviewed for comparable concurrent findings and bronchopulmonary dysplasia or retarded cerebral dystrophy lacking the other principal feature of this syndrome. Archival review revealed four similar cases and eight less so, without gene analysis. Further review for bronchopulmonary dysplasia revealed 59 cases, 1983-2006. Several other examples of similar retarded migration of germinal matrix and underdevelopment of cortical mantle, without pulmonary lesions of this type, were identified. The determination of an ABCA3 mutation in one case of severe pulmonary fibrosis with significant dystrophy of the brain and the identification of four highly similar archival cases and eight others with partial pathological findings supports the designation of an independent disorder, here referred to as the cerebropulmonary dysgenetic syndrome.
Probing Liquid Crystals with Nonlinear Optical Processes

Abstract Nonlinear optical effects provide some unique opportunities to study certain properties and structures of liquid crystal system. Examples are presented here to illustrate the potential of such studies.
FLORAL STRUCTURE AND EVOLUTION IN LOPEZIEAE (ONAGRACEAE)

independent lines), and decrease in floral symmetry with conversion to insect pollination (in at least two independent lines). The prominent tubercles on upper petals of certain insectpollinated species apparently evolved from the less prominent swollen areas still present in some of the bird-pollinated species. The tubercles and an associated snapping mechanism arose in response to increasing selection for fly pollination. Densely staining areas in some specimens may be osmophores; if so, scent plays a supplementary role in the orienting of insects to the upper petals. Interstaminal nectaries and the absence of a floral tube link the Lopezieae to Ludwigia; the relationship of these two taxa to Epilobium is presently unclear. Fossil records indicate that the Onagraceae had evolved by the beginning of the Tertiary Period and that the Ludwigia line is very old. The family's ancestral features are retained to a greater degree in Fuchsia, however, than in Ludwigia.
Morphometric studies of chloroquine induced autophagy in rat liver

Stereological principles were applied to the morphometric analysis of the autophagic process induced by the drug chloroquine (Abraham et al., 1968; Gray et al., 1973). Cellular autophagy is an important event to study because the series of complex subcellular events associated with it appear to help the cell to accommodate to stress. It was hoped that any subcellular changes that did occur during this process could be quantitated through morphometric analysis. Eight control animals were sacrificed, as well as two animals each at 1, 2 and 6hr following chloroquine administration. Five liver samples from each animal were prepared and examined in the TEM. Morphometric methods were used to characterize autophagic vacuoles, mitochondria, lysosomes, and peroxisomes according to their numerical density and relative volume within the hepatocyte (Weibel et al., 1969). Figure 1 is an example of a hepatocyte with numerous autophagic vacuoles containing lamellar membranes and/or ingested cytoplasmic organelles. More than 500 times the number of autophagic vacuoles observed in the control animals were found in those treated with chloroquine (Fig. 2). The volume per autophagic vacuole peaks at 2hr following drug treatment. Figures 3 and 4 illustrate the number per cell and the volume per organelle of the mitochondria, lysosomes and peroxisomes, expressed as a ratio with control values. In Fig. 3, the mitochondria demonstrate fluctuation in their number per cell over time, but they show a definite increase in volume (Fig. 4). Variation in the number of lysosomes per cell can also be seen in Fig. 3, although there is a definite decrease in their
FALSE POSITIVE DIAGNOSIS OF FETAL METHYLMALONIC ACID-EMIA DURING PREGNANCY WITH AN UNAFFECTED FETUS

FALSE POSITIVE DIAGNOSIS OF FETAL METHYLMALONIC ACID-EMIA DURING PREGNANCY WITH AN UNAFFECTED FETUS
Replacing trans fat: the argument for palm oil with a cautionary note on interesterification.

To replace dietary trans fatty acids (TFA), two practical options exist: revert to a natural saturated fat without cholesterol (most likely palm oil or its fractions) or move to a newer model of modified fat hardened by interesterification (IE). This review summarizes the relative risks for cardiovascular disease inherent in these options. Interestingly, both types of fat have been the subject of nutritional scrutiny for approximately the last 40 years, and both have positive and negative attributes. Only during that period has palm oil production developed to the point where it has become the major edible oil in world markets, making clinical studies of it an important objective. On the other hand, approximately 25 human studies have fed interesterified fat in one form or another over this period, some for weeks, some as a single meal. Two types of diet designs exist. Several fed a small amount of interesterified fat, usually incorporated within a margarine, and stayed below the radar of biological detec...
A LEED study of the (100) and (111) surfaces of the intermetallic compound FeTi

Two single crystals of FeTi, an intermetallic compound with a CsCl cubic structure, have been isolated from a bulk melt. After numerous cycles of concurrent argon bombardment and heating to at least 1200 K, clean and well-ordered surfaces appeared on both crystals, as determined by Auger electron spectroscopy (AES) and low energy electron diffraction (LEED). The first crystal produced a hexagonal pattern after heating to 1400 K. The measured lattice parameter is a0 = 4.3 ± 0.2 A compared to 4.2 A, which is the reported X-ray value for the (111) plane of FeTi. The second crystal became ordered at a lower temperature (1200 K) showing a square pattern corresponding to FeTi(100). The lattice parameter calculated from LEED was 3.1 ± 0.15 A, again in good agreement with X-ray data of 3.0 A. Sulfur readily segregates to the surface above 1000 K and orders to produce a c(2 × 2) pattern on the (100) face. This is the first observation of an ordered overlayer on an intermetallic compound.
Is spacetime duality violated in time dependent string solutions

Abstract We consider a class of exact solutions to string theory which have a compact direction whose radius is time dependent. We investigate whether there is some analog of the duality symmetry found in static solutions. It is shown that simply replacing the radius R by α ′/ R at each time does not even satisfy the classical field equations. A more general transformation does yield a solution, but it is shown to be inequivalent. It is argued that no duality symmetry exists for these spacetimes.
Dissolved organic carbon in marine pore waters: a comparison of three oxidation methods

Abstract Three methods for oxidizing dissolved organic carbon (DOC) in pore waters of marine sediment from Cape Lookout Bight, North Carolina are compared: (1) high temperature (850°C) sealed tube combustion (STC) of salts following vacuum distillation; (2) high temperature catalytic combustion (HTCC) using a Shimadzu TOC-500 Total Carbon Analyzer; (3) low temperature chemical oxidation (LTCO) with peroxydisulfuric acid in sealed glass ampoules. The STC method is sufficiently robust to oxidize refractory compounds such as diamond and graphite. Direct comparison with a Carlo Erba Elemental Analyzer established that the STC technique is capable of quantitatively oxidizing organic carbon contained in the sediment solid phase. Pore water DOC concentrations determined by STC and HTCC generally agree within the analytical error of the methods. The fraction of the DOC reservoir resistant to LTCO is less than 10%, indicating that these pore waters do not contain a large pool of DOC that is resistant to chemical oxidation.
Infants' search for hidden objects: Developing skills for using information selectively

A study with 9- and 16-month-olds investigated infants' developing skills for using conflicting sources of information about an object's location selectively. One goal of the research was to clarify conflicting findings concerning perseverative errors, which suggest that 9-month-olds may not know how to select appropriately between prior information (from A trials) and current information (from the hiding at B) about an object's location. A second goal was to directly examine how infants select between conflicting sources of information by comparing their performance in a conflict condition with their use of each of the two sources of information separately. The main finding was that both 9- and 16-month-olds showed some selectivity in choosing between the two kinds of information. Although use of both prior and current information improved with age, when the two were in conflict 9-month-olds, like 16-month-olds, selectively favored the current over the prior information. At the same time, 9-month-olds did make significant perseverative errors. These errors were not incompatible with some selectivity because, while frequent relative to other errors, they were not more frequent than correct responses. In general, the findings from this study suggest that the development of search involves more a gradual refinement of early skills than the acquisition of fundamentally new modes of searching.
Efficient Pathways of Excitation Energy Transfer from Delocalized S2 Excitons in the Peridinin–Chlorophyll a–Protein Complex

Excitation energy transfer (EET) in peridinin–chlorophyll–protein (PCP) complexes is dominated by the S1 → Qy pathway, but the high efficiencies cannot be solely explained by this one pathway. We postulate that EET from peridinin S2 excitons may also be important. We use complete active space configuration interaction calculations and the transition density cube method to calculate Coulombic couplings between peridinin and chlorophyll a in the PCP complex of the dinoflagellate Amphidinium carterae and compare monomeric and dimeric delocalized peridinin S2 excited states. Our calculations show that the S2 → Qy EET pathway from peridinin to chlorophyll a is the dominant energy transfer pathway from the S2 excited state in PCP, with several values in the sub-picosecond range. This result suggests that the S2 → Qy EET pathway may be responsible for the reported chlorophyll a bleaching signature seen in experiment at around 200 fs, and not the S2 → Qx pathway as previously suggested.
Liposome-Facilitated Enhancement of In Vitro Immunity to Human Colon Cancer

Liposome-antigens, in the presence of dialyzable leukocyte extracts (DLE)(1), were tested for their ability to enhance in vitro blastogenic responses to colon tumor antigens. Liposomes made with 6:4:1 molar ratios of phosphatidylcholine, cholesterol, and phosphatidic acid and bearing human colon cancer cell antigens were shown to be immunogenic in vitro, producing specific blastogenic responses. Addition of nonimmune DLE (500 micrograms/5 X 10(5) lymphocytes) in the in vitro culture system enhanced the blastogenic response 3x over liposome-antigen alone (p less than 0.001). Immune DLE (immune to keyhole limpet hemocyanin (KLH) and tuberculin (PPD) antigens) were suppressive (p less than 0.05) in the same study. Blastogenic reactivity to KLH was also generated in nonimmune lymphocytes and enhanced by liposomes with DLE specific to KLH (p less than 0.01). Nonspecific DLE (e.g., to PPD) caused suppression of KLH-induced blastogenesis (p less than 0.05). These findings confirm and extend prior reports noting that DLEs contain both specific and nonspecific lymphocyte blastogenic factors and suggest the use of this liposome-adjuvant system for boosting tumor immune responses.
Effect of ionic crosslinking on the swelling and mechanical response of model superabsorbent polymer hydrogels for internally cured concrete

The chemical and physical structure–property relationships of model superabsorbent polymer hydrogels were characterized with respect to swelling behavior and mechanical properties in different ionic solutions (Na+, Ca2+, and Al3+). The model hydrogels were composed of poly(sodium acrylate-acrylamide) (PANa-PAM) copolymer with varying concentrations of PANa (0, 17, 33, 67, and 83 wt%) and covalent crosslinking densities of 1, 1.5, and 2 wt%. By synthesizing the hydrogels in-house, systems with independently tunable amounts of covalent crosslinking and anionic functional groups were created, allowing for the relative effects of covalent and ionic crosslinking on the properties of the hydrogels to be directly quantified. It was found that the presence of Ca2+ and Al3+ in the absorbed fluid significantly decreased the swelling capacity and altered the swelling kinetics of the PANa-PAM hydrogels. The presence of Al3+ in solution resulted in the unexpected formation of a mechanically stiff barrier layer at the hydrogel’s surface, which hindered the release of fluid and caused the overall elastic modulus of the hydrogel to increase from O(10 kPa) for hydrogels immersed in Ca2+ solutions to O(100 kPa) for hydrogels immersed in Al3+ solutions. Tensile tests performed on isolated specimens of the stiff barrier layer yielded elastic moduli in the O(50–100 MPa) range.
Inconsistent definitions of "urban" result in different conclusions about the size of urban carbon and nitrogen stocks.

There is conflicting evidence about the importance of urban soils and vegetation in regional C budgets that is caused, in part, by inconsistent definitions of “urban” land use. We quantified urban ecosystem contributions to C stocks in the Boston (Massachusetts, USA) Metropolitan Statistical Area (MSA) using several alternative urban definitions. Development altered aboveground and belowground C and N stocks, and the sign and magnitude of these changes varied by land use and development intensity. Aboveground biomass (live trees, dbh ≥ 5 cm) for the MSA was 7.2 ± 0.4 kg C/m2 (mean ± SE), reflecting a high proportion of forest cover. Vegetation C was highest in forest (11.6 ± 0.5 kg C/m2), followed by residential (4.6 ± 0.5 kg C/m2), and then other developed (2.0 ± 0.4 kg C/m2) land uses. Soil C (0–10 cm depth) followed the same pattern of decreasing C concentration from forest, to residential, to other developed land uses (4.1 ± 0.1, 4.0 ± 0.2, and 3.3 ± 0.2 kg C/m2, respectively). Within a land use type, urban areas (which we defined as >25% impervious surface area [ISA] within a 1-km2 moving window) generally contained less vegetation C, but slightly more soil C, than nonurban areas. Soil N concentrations were higher in urban areas than nonurban areas of the same land use type, except for residential areas, which had similarly high soil N concentrations. When we compared our definition of urban to other commonly used urban extents (U.S. Census Bureau, Global Rural–Urban Mapping Project [GRUMP], and the MSA itself), we found that urban soil (1 m depth) and vegetation C stocks spanned a wide range, from 14.4 ± 0.8 to 54.5 ± 3.4 Tg C and from 4.2 ± 0.4 to 27.3 ± 3.2 Tg C, respectively. Conclusions about the importance of urban soils and vegetation to regional C and N stocks are very sensitive to the definition of urban used by the investigators. Urban areas, regardless of definition, are rapidly expanding in their extent; a systematic understanding of how our development patterns influence ecosystems is necessary to inform future development choices.