cssi/SciSciGPT-SciSciNet huggingface dataset:
PC-based machine-tool controller implemented as test bed for smart transducer interface

Machine-tool controllers are traditionally proprietary in design. Therefore, it is difficult to integrate third party hardware or software to enhance the functionality of either the machine tool or its controller. An open-architecture, PC-based controller merges as a good alternative. The Automated Production Technology Division at the National Institute of Standards and Technology, in collaboration with the US Navy, implemented an open-architecture, PC-based controller. This paper describes the design, implementation, and integration of this controller into a vertical machining center on the Portsmouth Naval Shipyard shop floor.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Time-delayed four-wave mixing using intense incoherent light.

Time-delayed four-wave mixing (TDFWM) on the 3S-3P transition in Na vapor has been studied using intense 7-nsec pulses from a broadband laser. Large-scale 1.9-psec modulation associated with the fine structure of the 3P state is observed throughout. At low buffer-gas pressures and low Na-vapor temperatures, pulse-induced relaxation effects are observed while at higher Na-vapor temperatures an anomalous response develops. In the normal region the TDFWM signal is interpreted in terms of either accumulated free decays or photon echoes. We estimate the relaxation induced by the excitation pulses.
Anion dependent self-assembly of "tetra-decker" and "triple-decker"luminescent Tb(III) salen complexes.

The Schiff base complexes [Tb3L4(H2O)2]Cl and [Tb3L3(OAc)2Cl] both have unusual multi-decker architectures formed via intramolecular π−π interactions between phenylene units.
Rhinocerebral mucormycosis: A case of a rare, but deadly disease

Rhinocerebral mucormycosis is a rare fungal infection of the nasal cavity and sinuses that can spread to the orbits and cranium within days. Its presentation can be confused with those of sinusitis, viral infections, diabetic ketoacidosis, or carotid sinus thrombosis, and it is often missed at early presentation. Survival is directly linked to early detection and treatment. We present a case of rhinocerebral mucormycosis and discuss the literature on its early signs and symptoms, pathophysiology, and treatment options.
Pressure-induced phase transformation in ZrW2O8 — Compressibility and thermal expansion of the orthorhombic phase

Abstract In situ neutron powder diffraction has been used to show that the application of hydrostatic pressure at room temperature produces a transformation of ZrW 2 O 8 from the cubic to an orthorhombic phase beginning at 2.1 kbar and completed by 3.1 kbar, with a 5% reduction in volume. After release of pressure, the orthorhombic phase is retained at room temperature. Its thermal expansion is negative below room temperature, but is positive above room temperature with a transformation back to the cubic phase at about 390 K. The WO 4 groups are found to play the dominant role in both phase transformations. The volume compressibilities of the cubic and orthorhombic phases are 1.38 × 10 −3 and 1.53 × 10 −3 kbar −1 , respectively.
Split-step Pad´e Migration

We introduce a split-step Pade migration method based on the one-way wave equation. The method uses the Padea pproxima- tion ofan exponential terminthe formalsolution of theone-way wave equation. It can produce high-quality images of complex structures with fewer numerical artifacts than those obtained us- ing a finite-difference parabolic-equation scheme that is based on the Padea pproximation of the square-root operator in the one-way wave equation. For a given model, the split-step Pade method is more efficient than the finite-difference parabolic- equation scheme because the former can use a larger grid spac- ing than the latter.
Protein evolution: structure-function relationships of the oncogene beta-catenin in the evolution of multicellular animals.

Beta-catenin functions as a cytoskeletal linker protein in cadherin-mediated adhesion and as a signal mediator in wnt-signal transduction pathways. We use a novel integrative approach, combining evolutionary, genomic, and three-dimensional structural data to analyze and trace the structural and functional evolution of beta-catenin genes. This approach also enabled us to examine the effects of gene duplication on the structure and function of beta-catenin genes in Drosophila, C. elegans, and vertebrates. By sampling a large number of different taxa, we identified both ancestral and derived motifs and residues within the different regions of the beta-catenin proteins. Projecting amino acid substitutions onto the three- dimensional structure established for mouse beta-catenin, we identified specific domains that exhibit loss and gain of selective constraints during beta catenin evolution. Structural changes, changes in the amino acid substitution rate, and the appearance of novel functional domains in beta-catenin can be mapped to specific branches on the metazoan tree. Together, our analyses suggest that a single, beta-catenin gene fulfilled both adhesion and signaling functions in the last common ancestor of metazoans some 700 million years ago. In addition, gene duplications facilitated the evolution of beta-catenins with novel functions and allowed the evolution of multiple, single-function proteins (cell adhesion or wnt-signaling) from the ancestral, dual-function protein. Integrative methods such as those we have applied here, utilizing the ‘natural experiments’ present in animal diversity, can be employed to identify novel and shared functional motifs and residues in virtually any protein among the proteomes of model systems and humans. J. Exp. Zool. (Mol. Dev. Evol.) 295B:25–44, 2003. © 2003 Wiley-Liss, Inc.
Is trust in others declining in America? An age-period-cohort analysis.

Analyzing survey data for the United States from 1972 to 1998, we assess the claim of Robert Putnam and others that interpersonal trust in America has eroded in recent decades. We examine changes in trust by attempting to estimate age, period, and cohort effects. We find a nonlinear aging effect: Trust is lowest among the youngest Americans, increases up to middle age, and then levels off. We also find over-time decreases in U.S. trust. These may stem from a nonlinear cohort effect: Generations born up to the 1940s exhibit high levels of trust, but each generation born after that is less trusting than the one before. We argue that some of the over-time decline might also stem from an age-specific period effect: Beginning in the 1980s the trust of young and middle-aged Americans declined steadily. We note that if successive generations continue to be less and less trusting, then through a process of cohort replacement U.S. society will become pervaded by mistrust.
The hydroacoustic behavior of piezoelectric composite materials

Abstract Piezoelectric composites that contain both ceramic and polymeric phases, and non-ferroelectric glass-ceramic composites have recently been developed. These materials exhibit attractive piezoelectric properties for applications in hydrophones that operate in a hydrostatic mode. Prototype hydrophones were developed using a porous PZT ceramic, a “0–3” and a “1–3” ceramic-polymer composite and a glass-ceramic sample. The test results on the acoustical performance of these devices are presented to demonstrate the potential of these new materials for underwater acoustical applications.
Expression of porcine Toll-like receptor 2, 4 and 9 gene transcripts in the presence of lipopolysaccharide and Salmonella enterica serovars Typhimurium and Choleraesuis

Salmonella enterica serovar Typhimurium (ST) and Choleraesuis (SC) are among the most frequently isolated salmonellae serovars causing enteric disease in swine. Enteric disease in young pigs is of major concern in modern production systems due to the negative implications on animal health, food safety and economic return. Epithelial cells express Toll-like receptors (TLR) that recognize conserved microbial structures and act as mediators of innate and adaptive immune responses. However, little is known about the expression of TLR gene transcripts in swine. The objective of the current study was to characterize the relative abundance of porcine TLR2, 4 and 9 gene transcripts in vitro in a porcine jejunal epithelial cell line (IPEC-J2) and in porcine mononuclear phagocytes (pMP) in the presence of ST or SC, as well as in vivo in the distal ileum of pigs orally challenged with ST. Our results indicate that TLR2, 4 and 9 are constitutively expressed in vitro in IPEC-J2 cells and pMP and in vivo in the distal ileum. Additionally, transient modulation of porcine TLR was observed in vitro and in vivo in the presence of ST and SC. Further investigation is warranted to determine the effects of ST and SC on functional TLR.
A growth-suppressive influence of L-isoproterenol on postnatally developing parotid gland of rat.

SummaryAdministration of l-isoproterenol for 8 days during the early phase of postnatal development when mitosis is normally high and cells are in the process of differentiation leads to suppression of mitotic rate and decrease in gland levels of DNA. Acceleration of differentiation, with increases in total RNA, cell and gland size were also observed. The accelerated differentiation may be the consequence of the inhibition of mitosis. If administration of isoproterenol is delayed until after weaning when cell division is markedly decreased and cells more nearly resemble those of adults, the usually expected hyperplasia as well as hypertrophy are observed. The spatial orientation of the β-adrenergic receptors appears to be a critical factor in these growth responses, since the d-isomer, injected in the same doses as the l-isomer, failed to cause significant effects. Finally, chronic administration of propranolol does not modify the course of postnatal growth in rat parotid, suggesting that β adrenergic rec...
Patterns of Career Choice and Career Decision-Making Self-Efficacy

Abstract This investigation examined the relationship between four patterns of career choice development during later adolescence/early adulthood and career decision-making self-efficacy. As predicted, persons whose career choice development reflected a stable or multiple trial pattern reported significantly greater levels of career decision-making self-efficacy than did persons whose career choice development reflected a conventional or unstable pattern. Further, persons in the stable pattern group were significantly more likely to nominate professionals in their chosen fields as important career role models than were persons with conventional and unstable career patterns. Implications for future research and career guidance are discussed.
Cancer incidence and mortality among workers exposed to acrylonitrile.

A cohort of 1,083 male employees who had potential for exposure to acrylonitrile between 1944 and 1970 at a Du Pont textile fibers plant were followed through 1981 for mortality and through 1983 for cancer incidence. In total, the 21 cancer deaths were fewer than expected based on either Du Pont or U.S. rates. No significant excesses were seen by primary site. In all, 37 cancer cases occurred as compared with 36.5 expected based on company rates. Five lung cancer cases were observed and 6.9 expected. There were 5 prostate cancer cases as compared with 1.9 expected. Of these, 4 occurred among wage employees during the 1975-1983 period, compared to 0.9 expected. This excess was statistically significant.
Accounting for short samples and heterogeneous experience in rating crop insurance

Purpose – The purpose of this paper is to be an academic inquiry into rating issues confronted by the US Federal Crop Insurance program stemming from changes in participation rates as well as the weighting of data to reflect longer‐run weather patterns.Design/methodology/approach – The authors investigate two specific approaches that differ from those adopted by the Risk Management Agency, building upon standard maximum likelihood and Bayesian estimation techniques that consider parametric densities for the loss‐cost ratio.Findings – Both approaches indicate that incorporating weights into the priors for Bayesian estimation can inform the distribution.Originality/value – In most cases, the authors' results indicate that including weighting into priors for Bayesian estimation implied lower premium rates than found using standard methods.
A familial risk of chronic renal failure among blacks on dialysis

End-stage renal disease (ESRD) is strongly associated with both hypertension and diabetes. As both diabetes and hypertension tend to be familial, we hypothesized a familial clustering of ESRD cases. Using 114 cases from three dialysis centers and 99 controls, the exposure odds ratio was determined. Mantel-Haenszel analysis demonstrated that individual history of hypertension (ORmh = 5.14; 95% Cl = 2.29-11.56) and history of chronic renal failure in a first or second degree relative (chi 2mh = 5.12; p less than 0.05) were significant "risk" factors for being dialysed for ESRD, while family history of hypertension posed a more questionable risk (ORmh = 1.92 95% Cl 0.96-3.86). In fact, when the subset of patients identified with hypertensive renal disease was considered independently, the risk due to family history of hypertension increased 14-fold which suggests a role as a confounder for hypertensive renal disease. The effect of chronic renal failure in a relative was independent of family history of diabetes.
New Hafnium Isotope, Hf 182

A new isotope of hafnium, ${\mathrm{Hf}}^{182}$, has been produced by double neutron capture in ${\mathrm{Hf}}^{180}$ in the intense neutron flux of the materials testing reactor (MTR). Mass spectrometric analysis of the irradiated hafnium gave a ${\mathrm{Hf}}^{182}$/${\mathrm{Hf}}^{180}$ atom ratio of 0.00147\ifmmode\pm\else\textpm\fi{}0.00001. The new isotope decays with a half-life of (9\ifmmode\pm\else\textpm\fi{}2)\ifmmode\times\else\texttimes\fi{}${10}^{6}$ years by ${\ensuremath{\beta}}^{\ensuremath{-}}$ emission predominantly to a 271-kev level in ${\mathrm{Ta}}^{182}$. The number of 271-kev gamma rays per ${\ensuremath{\beta}}^{\ensuremath{-}}$ disintegration is 0.84\ifmmode\pm\else\textpm\fi{}0.10. The $log\mathrm{ft}$ for the beta transition to the ${\mathrm{Ta}}^{182}$ ground state is g 15 indicating that this transition is at least third forbidden. The neutron capture cross section of ${\mathrm{Hf}}^{181}$ is ${40}_{\ensuremath{-}20}^{+40}$ barns.
Multiple Ras signals pattern the Drosophila ovarian follicle cells.

Abstract During Drosophila oogenesis, spatially restricted activity of the TORPEDO receptor tyrosine kinase first recruits follicle cells adjacent to the oocyte to a posterior cell fate and then specifies dorsal follicle cells. Another receptor tyrosine kinase, BREATHLESS, stimulates migration of the anterior follicle cells known as border cells. Since Ras is known to mediate many receptor tyrosine kinase effects, we have investigated the role of Ras in follicle cell fate determination, differentiation, and migration throughout oogenesis. Early ectopic Ras activity induced transient expression of posterior follicle cell markers in anterior follicle cells, but did not inhibit anterior differentiation. Later ectopic Ras activity inhibited anterior follicle cell differentiation but did not induce posterior marker expression. Complete transformation of anterior follicle cells to posterior follicle cells required early ectopic Ras activity in egg chambers where terminal differentiation of anterior cells was inhibited. These results suggest that, in vivo as in vitro, Ras can have diverse effects on different cells, but, in addition, Ras activity can have different effects on the same cells at different stages in their development.
Activation of NFAT signaling establishes a tumorigenic microenvironment through cell autonomous and non-cell autonomous mechanisms

NFAT (the nuclear factor of activated T cells) upregulation has been linked to cellular transformation intrinsically, but it is unclear whether and how tissue cells with NFAT activation change the local environment for tumor initiation and progression. Direct evidence showing NFAT activation initiates primary tumor formation in vivo is also lacking. Using inducible transgenic mouse systems, we show that tumors form in a subset of, but not all, tissues with NFATc1 activation, indicating that NFAT oncogenic effects depend on cell types and tissue contexts. In NFATc1-induced skin and ovarian tumors, both cells with NFATc1 activation and neighboring cells without NFATc1 activation have significant upregulation of c-Myc and activation of Stat3. Besides known and suspected NFATc1 targets, such as Spp1 and Osm, we have revealed the early upregulation of a number of cytokines and cytokine receptors, as key molecular components of an inflammatory microenvironment that promotes both NFATc1(+) and NFATc1(-) cells to participate in tumor formation. Cultured cells derived from NFATc1-induced tumors were able to establish a tumorigenic microenvironment, similar to that of the primary tumors, in an NFATc1-dependent manner in nude mice with T-cell deficiency, revealing an addiction of these tumors to NFATc1 activation and downplaying a role for T cells in the NFATc1-induced tumorigenic microenvironment. These findings collectively suggest that beyond the cell autonomous effects on the upregulation of oncogenic proteins, NFATc1 activation has non-cell autonomous effects through the establishment of a promitogenic microenvironment for tumor growth. This study provides direct evidence for the ability of NFATc1 in inducing primary tumor formation in vivo and supports targeting NFAT signaling in anti-tumor therapy.
The timer-logger-communicator gait monitor: Recording temporal gait parameters using a portable computerized device

A portable microprocessor-based device, the timer-logger-communicator (TLC), was adapted and connected to footswitches to monitor and record temporal gait parameters in 25 hemiplegic and 30 normal subjects. Controls walked at 1.36 m/s with symmetric gait. Hemiplegic subjects had a mean walking speed of 0.43 m/s, asymmetric gait, and varying proportions of time spent in each phase, consistent with previously reported gait parameters. Trends in objective gait measures more closely paralled trends in functional ambulation classification than in Brunnstrom motor recovery stages. The TLC gait monitor is a useful instrument to measure temporal parameters of gait in the clinical setting.
Nonlinear optical studies of monomolecular films under pressure.

Nonlinear optical techniques (second-harmonic and sum-frequency generation) have been used to study the structure of organic molecules that are confined and compressed between a lens and a flat surface. The molecules studied include self-assembled monolayers of n-octadecyltriethoxysilane and Langmuir-Blodgett films of stearic acid, octadecylalcohol, octadecylamine, and a liquid-crystal molecule 4'-n-octyl-4-cyanobiphenyl (8CB). The contact area created by elastic deformation of the flat surface and lens under pressure was large enough to contain the entire laser beam (g100 \ensuremath{\mu}m radius at \ensuremath{\approxeq}10 MPa for R=15 cm). Under these conditions, the sum-frequency generation (from ${\mathrm{CH}}_{3}$ and OH stretch modes) and second-harmonic generation (8CB) signals were found to decrease by a factor between 100 and 1000 times the original signal. This indicates vanishing of the second-order monolayer susceptibility due to disorder of the head groups and/or flattening of the molecular axis so that they lie parallel to the surface. The phenomenon was reversible and the nonlinear signals recovered completely upon removal of the pressure.
Key morphologic changes and DNA strand breaks in human lymphoid cells: Discriminating apoptosis from necrosis

Apoptosis is an important form of physiologic cell death displayed by an enormous variety of tissues under divergent conditions. The recent attention toward apoptosis in virtually all aspects of modern biology indicates that rapid and accurate differentiation between apoptosis and necrotic death is of considerable interest. Apoptosis is distinguishable from necrosis on the basis of several criteria. In this study, we undertook to examine the effects of mild hyperthermia (43 degrees C leading to apoptotic death) and severe hyperthermia (50 degrees C leading to necrotic killing) on associated DNA fragmentation. Using laser scanning and fluorescent microscopic evaluation of DNA "comets" in the single cell gel assay, we compared necrotic and apoptotic DNA damage in a variety of human leukemia and lymphoma cell lines at the level of the individual cell. We show that necrotic cells do display detectable DNA damage. We confirm our preliminary report that comet "tail moment" is sufficient to distinguish between necrotic and apoptotic DNA damage, while comet tail length may confuse the two forms. We report that a recovery period is necessary for expression of increasing apoptotic but not necrotic DNA damage. We show that apoptosis increases with prolonged hyperthermia and confirm that the mode of death changes from apoptosis to necrosis with higher heat loads, producing a greater fraction of cells showing damage. In addition, we show that for necrotic cells, DNA tail moment reflects sensitivity to prolonged exposure without a concomitant change in tail length.
Novel folate binding protein-1 interactions in embryonic orofacial tissue

Aim To identify proteins with which FolBp1 may interact within lipid rafts in tissue derived from embryonic orofacial tissue.
Boundary layer in shape optimization of convective fins using a meshfree approach

We show how shape optimization of fin arrays for increased heat flux through the base under area constraint leads to non-existence of optimal solutions. An additional constraint in terms of the boundary layer eliminates the apparent paradox. We consider a variable heat transfer coefficient and we use a fixed-point iteration scheme to solve the resulting non-linear boundary value problem for the steady-state heat operator with temperature, flux, and convection boundary conditions. We propose a simple yet effective algorithm for evaluating the boundary layer constraint and eliminating the constraint violation. There are large shape changes between the initial and final design but no remeshing is required because we use a meshfree method that is not sensitive to shape distortion of integration cells as long as they remain convex. The resulting optimal unit cell is repeated by periodicity to produce the optimal fin array. The obtained shapes display similarities to shapes seen in natural systems governed by diffusion/convection and conduction processes. A length-scale for the unit cell is naturally introduced by the non-overlap condition imposed on the thermal boundary layer in the cooling ambient fluid. Copyright © 2004 John Wiley & Sons, Ltd.
Local heating of human skin by millimeter waves: Effect of blood flow

We investigated the influence of blood perfusion on local heating of the forearm and middle finger skin following 42.25 GHz exposure with an open ended waveguide (WG) and with a YAV mm wave therapeutic device. Both sources had bell-shaped distributions of the incident power density (IPD) with peak intensities of 208 and 55 mW/cm(2), respectively. Blood perfusion was changed in two ways: by blood flow occlusion and by externally applied vasodilator (nonivamide/nicoboxil) cream to the skin. For thermal modeling, we used the bioheat transfer equation (BHTE) and the hybrid bioheat equation (HBHE) which combines the BHTE and the scalar effective thermal conductivity equation (ETCE). Under normal conditions with the 208 mW/cm(2) exposure, the cutaneous temperature elevation (DeltaT) in the finger (2.5 +/- 0.3 degrees C) having higher blood flow was notably smaller than the cutaneous DeltaT in the forearm (4.7 +/- 0.4 degrees C). However, heating of the forearm and finger skin with blood flow occluded was the same, indicating that the thermal conductivity of tissue in the absence of blood flow at both locations was also the same. The BHTE accurately predicted local hyperthermia in the forearm only at low blood flow. The HBHE made accurate predictions at both low and high perfusion rates. The relationship between blood flow and the effective thermal conductivity (k(eff)) was found to be linear. The heat dissipating effect of higher perfusion was mostly due to an apparent increase in k(eff). It was shown that mm wave exposure could result in steady state heating of tissue layers located much deeper than the penetration depth (0.56 mm). The surface DeltaT and heat penetration into tissue increased with enlarging the irradiating beam area and with increasing exposure duration. Thus, mm waves at sufficient intensities could thermally affect thermo-sensitive structures located in the skin and underlying tissue.
Brain-targeted delivery of Tempol-loaded nanoparticles for neurological disorders

Brain-targeted Tempol-loaded poly-(lactide-co-glycolide) (PLGA) nanoparticles (NPs) conjugated with a transferrin antibody (OX 26) were developed using the nanoprecipitation method. These NPs may h...
Importance of the Phyllochron in Studying Development and Growth in Grasses

The phyllochron, which is defined as the interval between similar growth stages of successive leaves on the same culm, has been used extensively to describe and understand development of grasses. The purpose of this paper is to introduce seven papers presented as part of the symposium Understanding Development and Growth in Grasses: Role of the Phyllochron Concept. Environmental (temperature, water, and day length) factors and genetics affect the duration of the phyllochron. The following seven papers broaden the discussion of these topics and present new concepts about how the environment and genetics impact the relationship between leaf appearance and whole plant development
Use of ς with the Future Participle in Herodotus as an Indicator of Unfulfilled Expectations

An examination of Herodotus’s use of the circumstantial participle in the future tense with and without the adverbial particle ς reveals that Herodotus reserves ς almost exclusively for those cases in which the expectations or intentions represented by the participle are ultimately disappointed. This observation should teach us to distrust the conventional assertion that the appearance of ς with the circumstantial participle has no implications for an author’s thoughts. It also suggests that, in those cases where we lack direct knowledge of historical outcomes, the presence of ς with a circumstantial participle may permit us to be reasonably certain that any expectations or intentions expressed by that participle are likely to have gone unfulfilled. Thus, Herodotus’s use of the phrase ς νασοντeς at the end of the Histories to refer to the Athenians’ intentions to dedicate the equipment from Xerxes’ bridge (9.121) should probably be understood as implying that no such dedication ever took place.
Models and Scheduling Algorithms for Mixed Data and Task Parallel Programs

An increasing number of scientific programs exhibit two forms of parallelism, often in a nested fashion. At the outer level, the application comprises coarse-grained task parallelism, with dependencies between tasks reflected by an acyclic graph. At the inner level, each node of the graph is a data-parallel operation on arrays. Designers of languages, compilers, and runtime systems are building mechanisms to support such applications by providing processor groups and array remapping capabilities. In this paper we explore how to supplement these mechanisms with policy. What properties of an application, its data size, and the parallel machine determine the maximum potential gains from using both kinds of parallelism? It turns out that large gains can be expected only for specific task graph structures. For such applications, what are practical and effective ways to allocate processors to the nodes of the task graph? In principle one could solve the NP-complete problem of finding the best possible allocation of arbitrary processor subsets to nodes in the task graph. Instead of this, our analysis and simulations show that a simpleswitchedscheduling paradigm, which alternates between pure task and pure data parallelism, provides nearly optimal performance for the task graphs considered here. Furthermore, our scheme is much simpler to implement, has less overhead than the optimal allocation, and would be attractive even if the optimal allocation was free to compute. To evaluate switching in real applications, we implemented a switching task scheduler in the parallel numerical library ScaLAPACK and used it in a nonsymmetric eigenvalue program. Even for fairly large input sizes, the efficiency improves by factors of 1.5 on the Intel Paragon and 2.5 on the IBM SP-2. The remapping and scheduling overhead is negligible, between 0.5 and 5%.
Development of a compact tunable laser-driven Compton scattering x-ray source for protein crystallography

A complete, 3D theory of Compton scattering is described, which fully takes into account the effects of the electron beam emittance and energy spread upon the scattered x-ray spectral brightness. In the linear regime, and in the absence of radiative corrections; it is found that each vacuum eigenmode gives rise to a single Doppler-shifted classical dipole excitation. This formalism is then applied to Compton scattering in a 3D laser focus, and yields a complete description of the influence of the electron beam phase space topology on the x-ray spectral brightness; analytical expressions including the effects of emittance and energy spread are also obtained in the 1D limit. Within this framework, the x-ray brightness generated by a 25 MeV electron beam is modeled, fully taking into account the beam emittance and energy spread, as well as the 3D nature of the laser focus; its application to x-ray protein crystallography is outlined.
LIBBY ET AL. RESPOND

We welcome the opportunity to continue the dialogue on studying American Indians’ experiences with child welfare systems. While Thompson agrees on the importance of such disparities research and a focus on caregivers, he raises an interesting question about the appropriate reference group for racial/ethnic comparisons. Our decision to use American Indian care-givers as the reference group was hypothesis driven. We were investigating whether disparities exist for American Indian caregivers compared with others in the United States; in the interest of space, we did not report all possible contrasts. However, an interested reader could have examined all comparisons by looking at the results shown in Table 2 of our article. For example, dividing the odds ratio for Whites (2.32) by the odds ratio for Blacks (1.39) results in an odds ratio of 1.67, which is identical to the odds ratio that would have been obtained for the White subgroup if the model had been estimated with Blacks as the reference group. Standard errors, however, cannot be obtained from the table. Our choice of reference group was also reasonable statistically. We agree that a reference group should be sufficiently large to allow for reasonably precise estimates, as ours did (160/968 unweighted; 20163/308958 weighted). The fact that our estimate for a contrasted subgroup (Hispanics) was statistically significant is evidence that the American Indian group was large enough to act as the reference group. It is also important to note that changing the reference group does not change the parameter estimates for any other variables in the model or the overall test of the model (here the F statistic). Regardless of the reference group, the precision of parameter estimates for small subgroups may be compromised, as evidenced by standard errors; in our case these were slightly larger for American Indians and Hispanics (proportionally smaller subgroups) than for Whites and Blacks. The issue is thus not which subgroup is the reference group, but small subgroups in general. Our assertion that “Hispanic caregivers fared the best”1(p630) referred to the fact that, as shown in Table 1, Hispanic caregivers received more assessments and service referrals and had higher rates of prior service receipt than White, Black, and American Indian caregivers. It is time for disparities research to move beyond rote comparisons with Whites. Rather, we should concentrate on considering and proposing hypotheses to be tested.
Iridium nanocrystal synthesis and surface coating-dependent catalytic activity.

Iridium (Ir) nanocrystals were synthesized by reducing (methylcyclopentadienyl)(1,5-cyclooctadiene)Ir with hexadecanediol in the presence of four different capping ligand combinations: oleic acid and oleylamine, trioctylphosphine (TOP), tetraoctylammonium bromide (TOAB), and tetraoctylphosphonium bromide (TOPB). The oleic acid/oleylamine-capped nanocrystals were of the highest quality, with the narrowest size and shape distribution. The Ir nanocrystals were tested for their ability to catalyze the hydrogenation of 1-decene as a model reaction. The oleic acid/oleylamine and TOP-capped nanocrystals were both catalytically dead. TOAB and TOPB-coated nanocrystals both catalyzed 1-decene hydrogenation, with the TOPB-coated nanocrystals exhibiting the highest turnover frequencies. Recycling through several catalytic reactions increased the catalytic activity, presumably as a result of ligand desorption and increased exposure of the metal surface, with ligand desorption eventually leading to precipitation and s...
Raman and site-selective fluorescence spectra of model compounds for interchain interactions in poly(phenylenevinylene)

Abstract Nonresonant Raman spectra and site-selective fluorescence spectra (polyethylene matrix, 1.5 K) are reported for 1,4-distyrylbenzene, its tert -butyl and paracyclophane substituted derivatives, and the paracyclophane derivative bearing two distyrylbenzene chains in a pseudo- para orientation, a simple model for the interchain interactions in poly(phenylene-vinylene) films. The first three compounds show pronounced fluorescence line-narrowing when excited near the red edge of their absorption spectra. The bichromophoric compound exhibits no narrowing although its Raman spectrum, room-temperature fluorescence spectrum, and lifetime are similar to those of the other three molecules. This may reflect increased low-frequency Franck–Condon activity in the electronically delocalized bichromophoric system.
MULTIPLE-SITE ADSORPTION OF CD, CU, ZN, AND PB ON AMORPHOUS IRON OXYHYDROXIDE

Abstract Adsorption of Cd, Zn, Cu, and Pb onto amorphous iron oxyhydroxide was measured as a function of pH, metal ion concentration, and adsorbent concentration. For each metal, there is a narrow pH band where fractional adsorption increases from near nil to near 100%. For fixed adsorbent concentration, the pH region of the pH-adsorption edge is independent of total adsorbate concentration when adsorption density is less than 10 −5.0 , 10 −3.7 , and 10 −2.3 moles adsorbate per mole Fe for adsorption of Cd, Cu, and Zn, respectively. At larger adsorption densities for these three metals and over the entire range of adsorption densities studied for Pb, the pH region of the adsorption edge becomes more alkaline as total adsorbate concentration increases. In no case did adsorption density attain a maximum, limiting value. The results suggest that the surface is composed of many groups of binding sites. The strength of binding between a given metal and the surface may vary by an order of magnitude or more from one site to another. At small adsorption densities all types of sites are available in excess, and adsorption can be described by the Langmuir isotherm. However, at higher adsorption densities, availability of the strongest binding sites decreases, leading to a decrease in the apparent adsorption equilibrium constant. This phenomenon occurs under conditions where only a few percent of all surface sites are occupied, and is inconsistent with available single-site models.
Structural details, pathways, and energetics of unfolding apomyoglobin.

Protein folding is often difficult to characterize experimentally because of the transience of intermediate states, and the complexity of the protein-solvent system. Atomistic simulations, which could provide more detailed information, have had to employ highly simplified models or high temperatures, to cope with the long time scales of unfolding; direct simulation of folding is even more problematic. We report a fully atomistic simulation of the acid-induced unfolding of apomyoglobin in which the protonation of acidic side-chains to simulate low pH is sufficient to induce unfolding at room temperature with no added biasing forces or other unusual conditions; and the trajectory is validated by comparison to experimental characterization of intermediate states. Novel insights provided by their analysis include: characterization of a dry swollen globule state forming a barrier to initial unfolding or final folding; observation of cooperativity in secondary and tertiary structure formation and its explanation in terms of dielectric environments; and structural details of the intermediate and the completely unfolded states. These insights involve time scales and levels of structural detail that are presently beyond the range of experiment, but come within reach through the simulation methods described here. An implicit solvation model is used to analyze the energetics of protein folding at various pH and ionic strength values, and a reasonable estimate of folding free energy is obtained. Electrostatic interactions are found to disfavor folding.
The Politics of Torts: Explaining Litigation Rates in the American States

Debate rages over whether Americans have become enormously litigious, but little research considers why Americans file cases in the first place or adequately considers rates of litigation over time. This article examines tort filings in ten representative states over a twenty-year period and analyzes the impact of social, political, policy, and legal system factors that may account for case filings. We find that filing rates vary substantially over time within individual states, which adds to cautions about claims of general litigiousness. Our analysis also demonstrates that social complexity, opportunities for political participation, and social policy are the most important explanations for variations in filing rates. The tendency of Americans to use the courts to resolve disputes is related to the milieu in which they live and how the political system responds to demands for participation and social support.
Sex, power, and dependency: the politics of adolescent sexuality

This study examines the social psychological determinants of adolescent sexual activity. Drawing on power-dependency theory within a social exchange framework, a conceptual model of adolescent sexuality is developed and tested using survey data on 288 teenagers. It is hypothesized that attributes of power (confidence with members of the opposite sex, popularity, opposite-sex friends, and egalitarian gender role attitudes) would indirectly decrease sexual activity (participation in unwanted sex and the extent of intimate sexual behaviors) through their negative effect on dependence (discomfort with physical appearance, the need for self-disclosure and closeness, the need for physical gratification in sex and the need for emotional gratification in sex). The findings indicate that the model is a good predictor of the sexual activity of adolescent males for whom dependency is an important determinant of sexual behavior. When the model is estimated separately for the Black and white teenagers, distinct patterns are observed for the Black females. Black females' participation in unwanted sex is far below the average for the other subgroups, and the most influential factor in decreasing coercion for Black females is nontraditional gender role attitudes.
How to counteract chemophobia

Michelle Francl ponders ways in which we can talk about chemistry without triggering chemophobia.
Studies of the mechanism of the anodic oxidation of ethylene in acid and alkaline media

Abstract The ethylene oxidation reaction on smooth and platinized platinum has been studied at 80°C in solutions of H2SO4 + K2SO4 and NaOH + K2SO4 of constant ionic strength = 1.5. Reaction rates were measured as a function of potential, pH and partial pressure of ethylene. Coulombic efficiency of the reaction was determined by measurements of CO2 production in acidic solutions, and of C2H4 consumption in alkaline solutions. The following parameters have been found: Coulombic efficiency is 100 ± 1% in acidic and 90 ± 5% in alkaline solutions, i0 = 10−8 A cm−2 on platinized and 10−10 A cm−2 on smooth Pt respectively. Activation energy A = 17 ± 2 kcals. At higher overpotentials diffusion limiting current was obtained. At V = 0.9 (R.H.E.), the current drops to negligible values due to the oxide formation. Coverage of the electrode with the ethylenic radical at 1 atm has been evaluated by two independent methods as θE = 0.55 ± 0.2. The reaction mechanism in the Tafel potential range was interpreted in terms of water discharge as the rate-determining step over the complete pHrangeinvestigated. In the potential range higher than that of the Tafel region the rate control is shifted to mass transport of ethylene. At PE = 1 atm, the Tafel potential range is limited by oxide formation before diffusion control sets in. A possible explanation of the anomalous pH effect in reactions concerning water discharge has been given.
Orthotopic liver transplantation for patients with hepatitis B virus–related liver disease

Fifty-nine patients with prior hepatitis B virus infection underwent orthotopic liver transplantation. During the first 2 mo, mortality was not significantly different in the hepatitis B virus–infected group (25.5%) vs. a hepatitis B virus–immune control group (21 %). Beyond 2 mo, the mortality, rate of graft loss, need for retransplantation and incidence of abnormal liver function were significantly higher in the hepatitis B virus–infected group. Treatment of the hepatitis B virus infection was attempted with passive immunization, combined active and passive immunization, α-interferon or nothing. The clinical outcome was not significantly influenced by any of these therapies. However, of the patients who lived more than 60 days, 6 of 22 treated with active plus passive immunization were cleared of HBsAg, something achieved once in 16 patients treated with α-interferon, never in 3 patients with passive immunization only and once in 4 patients with no therapy. In patients with recurrent hepatitis B virus infection, the pace of hepatitis development in the graft appeared to be accelerated, and this was particularly striking in patients who underwent multiple retransplantations at progressively shorter intervals. None of the patients who became HBsAg-negative had HBeAg preoperatively.
Modeling Regional Agricultural Production and Salinity Control Alternatives for Water Quality Policy Analysis

Water development and allocation to competing uses without well-defined water quality rights contribute to water use externalities. Federal legislation to address the salinity externalities in the Colorado River Basin comprises a set of arbitrary quality standards and millions of dollars in federal projects. This study specifies economic criteria to empirically determine first- and second-best quality standards and to indicate opportunities for efficiency gains in existing policy. A basin-wide, nonlinear programming model optimizes river water quality, resource allocation, production levels, and total expenditures for control. Revealed are the economic tradeoffs between water uses, regions, and control strategies.
Responsiveness of Female Aedes Aegypti (Diptera: Culicidae) to Flower Extracts

Extracts of common milkweed ( Asclepias syriaca ) were prepared with 5 solvents having a range of polarities. These extracts were tested for attractiveness to Aedes aegypti females by using an olfactory probing response test, which measured the proportion of mosquitoes probing toward an extract residue. The extracts did not significantly differ from one another in attractiveness. A methanol extract of common milkweed, a methylene chloride extract of Canada goldenrod ( Solidago canadensis ), and a diethyl ether extract of honey were used in experiments to examine changes in mosquito responsiveness during food deprivation following 3 events: (a) emergence, (b) engorgement on a 5% sucrose solution, and (c) engorgement on blood. Mosquitoes did not respond at emergence or immediately after a sucrose or blood meal, but they became progressively more responsive with increasing food deprivation. The honey extract was more attractive than milkweed in the early stages of deprivation, and milkweed extract was more attractive than both goldenrod and honey extracts in the late stages of deprivation. The return of responsiveness to milkweed occurred sooner after the sucrose meal than after the blood meal. After the blood meal, responsiveness remained low until the oviposition period.
Modest hormonal effects of soy isoflavones in postmenopausal women.

Soy isoflavones have been hypothesized to exert hormonal effects in postmenopausal women. To test this hypothesis, we studied the effects of three soy powders containing different levels of isoflavones in 18 postmenopausal women. Isoflavones were consumed relative to body weight[ control: 0.11 ± 0.01; low isoflavone (low-iso): 1.00 ± 0.01; high isoflavone (high-iso): 2.00 ± 0.02 mg/kg/day] for 93 days each in a randomized crossover design. Blood was collected on day 1 of the study (baseline) and days 36–38, 64–66, and 92–94 of each diet period, for analysis of estrogens, androgens, gonadotropins, sex hormone binding globulin (SHBG), prolactin, insulin, cortisol, and thyroid hormones. Vaginal cytology specimens were obtained at baseline and at the end of each diet period, and endometrial biopsies were performed at baseline and at the end of the high-iso diet period, to provide additional measures of estrogen action. Overall, compared with the control diet, the effects of the low-iso and high-iso diets were...
Das Muskelfäserchen (Muskelfibrille, Myofibrille, Myofibril)

Ganz wie die Muskelfaser hat auch die Muskelfibrille eine doppelte Gliederung, eine axiale und eine transversale. Die transversale oder quere Gliederung (parallel mit der Querachse) wird dargestellt durch die verschiedenen von der Lichtmikroskopie her bekannten Bander und Zonen, die fur die Querstreifung aller quergestreiften Muskulatur verantwortlich sind. Auf sie wird sogleich eingegangen werden. Die axiale Gliederung parallel der Langsachse der Muskelfibrille ist durch deren Zusammensetzung aus feinsten Elementen, den Urfaserchen oder Protofibrillen, bedingt. In dieser Hinsicht ist kein wesentlicher Unterschied zwischen den Myofibrillen der Skelettmuskulatur und der Herzmuskulatur festzustellen. Beide zeigen, wie unsere Bilder erkennen lassen, grundsatzlich denselben Aufbau.
Masked intervention effects: Analytic methods for addressing low dosage of intervention

Using the Coping Power Program (Lochman, Wells, and Murray, forthcoming) as an example of an evidence-based program for aggressive children, this report compares alternative analysis strategies for program evaluation and describes potential drawbacks of using intent-to-treat (ITT) analyses to examine intervention effects and presents several additional analytic methods as alternatives to ITT.