cssi/SciSciGPT-SciSciNet huggingface dataset:
Photoconversion kinetics of chloroplast Photosystems I and II. Effect of Mg2

Abstract The effect of divalent cations on the primary photoconversion kinetics of chloroplast Photosystems (PS) I and II was investigated by absorbance difference spectrophotometry in the ultraviolet (ΔA320) and red (ΔA700) regions and by fluorescence at room temperature. Three main chlorophyll (Chl) a fluorescence emission components were identified. Addition of 5 mM MgCl2 to unstacked chloroplasts caused a 5–7-fold increase in Fvα, the variable fluorescence yield controlled by the α-centers. The fluorescence yield Fvβ controlled by the β-centers and the nonvariable fluorescence yield F0 were only slightly changed by the treatment. The absolute number of α- and β-centers remained unchanged and independent of divalent cations. The rate constants Kα, Kβ and KP-700 determined from the photoconversion kinetics of Qα, Qβ and P-700 were also unchanged by divalent cations, suggesting a constancy of the respective absorption cross-sections. Evidence is presented that the Mg2+ effect on Chl a fluorescence is not due simply to unstacking. Conclusion: (1) In the absence of divalent cations from the chloroplast suspending medium, the variable fluorescence yield is not complementary to the rate of PS II photochemistry. (2) A spillover of excitation from PS II to PS I in the absence of Mg2+ cannot account for the 7-fold lowering of the variable fluorescence yield Fvα at room temperature. The results are discussed in view of a model of excitation transfer and fluorescence emission in the pigment bed of PS IIα and PS IIβ.
Intracellular traffic and plasma membrane secretion of small organic solutes involved in hepatocellular bile formation

Abstract Bile formation by the liver in humans involves the secretion of gram quantities of bile salts, phosphatidylcholines, and cholesterol per day. Bile salts are amphiphilic detergents capable of solubilizing membranes, and phosphatidylcholine and cholesterol are membrane constituents that are only sparingly soluble in water. Intracellular trafficking of these molecules is primarily via binding to cytosolic proteins, although vesicles may play a role. Although bile salts interact reversibly with intracellular organelles, they are secreted as monomers into bile by specific apical transport proteins. Phosphatidylcholines are derived primarily from the endoplasmic reticulum, are delivered to the inner hemileaflet of the apical membrane via cytosolic binding proteins, and are translocated to the outer hemileaflet; the mdr2 P-glycoprotein gene product is thought to play a prominent role in the last process. Cholesterol contained in plasma lipoproteins arrives either via lateral diffusion along the plasma membrane, or is released from lysosomal degradation of cholesteryl esters. Bile salts secreted into the canalicular lumen promote the formation of phospholipid vesicles on the exoplasmic face of the canalicular membrane, possibly by vesiculating microdomains of biliary-type phosphatidylcholine molecules in the outer hemileaflet. Mechanisms for cholesterol secretion into bile are as yet unknown. Intracellular trafficking and the coordinated, specific secretion of these molecules enables the massive movement of membrane-active molecules through hepatocytes, without causing damage to the cell.
Accounting for the long-term effects of a marketing contact

Organizations that use data mining ''scoring'' models to estimate the expected revenue resulting from sending a customer some marketing contact such as a catalog, solicitation for a donation, or other offers are underestimating the value of the contact and under-investing in their customers. When a customer responds to the contact the organization will receive the revenue due to the order, which is estimated by the scoring model, but it also benefits because the customer has become a better customer and will thus be more responsive to future contacts. The paper proposes a correction that accounts for the incremental change in customer status and illustrates the correction on two data sets from different industries. In both cases we find that the magnitude of the correlation approximately equals that of the short-term return from the contact. The correction is highly correlated with short-term returns and so the correction has little effect on the rank ordering of the customers. Topics for future research are identified.
Mechanism of the C5 Stereoinversion Reaction in the Biosynthesis of Carbapenem Antibiotics

The bicyclic β-lactam/2-pyrrolidine precursor to all carbapenem antibiotics is biosynthesized by attachment of a carboxymethylene unit to C5 of L-proline followed by β-lactam ring closure. Carbapenem synthase (CarC), an Fe(II) and 2-(oxo)glutarate (Fe/2OG)-dependent oxygenase, then inverts the C5 configuration. Here we report the structure of CarC in complex with its substrate and biophysical dissection of its reaction to reveal the stereoinversion mechanism. An Fe(IV)-oxo intermediate abstracts the hydrogen (H•) from C5, and tyrosine 165, a residue not visualized in the published structures of CarC lacking bound substrate, donates H• to the opposite face of the resultant radical. The reaction oxidizes the Fe(II) cofactor to Fe(III), limiting wild-type CarC to one turnover, but substitution of the H•-donating tyrosine disables stereoinversion and confers to CarC the capacity for catalytic substrate oxidation.
Association of Surgical Care Improvement Project Infection-Related Process Measure Compliance with Risk-Adjusted Outcomes: Implications for Quality Measurement

Background Facility-level process measure adherence is being publicly reported. However, the association between measure adherence and surgical outcomes is not well-established. Our objective was to determine the degree to which Surgical Care Improvement Project (SCIP) process measures are associated with American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) risk-adjusted outcomes. Study Design This cross-sectional study included hospitals participating in the ACS NSQIP and SCIP (n = 200). ACS NSQIP outcomes (30-day overall morbidity, serious morbidity, surgical site infections [SSI], and mortality) and adherence to SCIP SSI-related process measures (from the Hospital Compare database) were collected from January 1, 2008, through December 31, 2008. Hospital-level correlation coefficients between compliance with 4 process measures (ie, antibiotic administration within 1 hour before incision [SCIP-1]; appropriate antibiotic prophylaxis [SCIP-2]; antibiotic discontinuation within 24 hours after surgery [SCIP-3]; and appropriate hair removal [SCIP 6]) and 4 risk-adjusted outcomes were calculated. Regression analyses estimated the contribution of process measure adherence to risk-adjusted outcomes. Results Of 211 ACS NSQIP hospitals, 95% had data reported by Hospital Compare. Depending on the measure, hospital-level compliance ranged from 60% to 100%. Of the 16 correlations, 15 demonstrated nonsignificant associations with risk-adjusted outcomes. The exception was the relationship between SCIP-2 and SSI (p = 0.004). SCIP-1 demonstrated an intriguing but nonsignificant relationship with SSI (p = 0.08) and overall morbidity (p = 0.08). Although adherence to SCIP-2 was a significant predictor of risk-adjusted SSI (p Conclusions Better adherence to infection-related process measures over the observed range was not significantly associated with better outcomes with one exception. Different measures of quality might be needed for surgical infection.
The Influence of Supportive Parenting and Racial Socialization Messages on African American Youth Behavioral Outcomes

A warm and supportive parent–child relationship is one of the most crucial determinants of positive outcomes in racially and socioeconomically diverse youth. There is, however, limited understanding of the diverse and unique parenting practices of racially diverse families, particularly those from under-resourced communities. Little empirical research has considered the utility of combining universal and culturally-specific parenting strategies to benefit under-resourced racially diverse youth outcomes. Thus, the purpose of our study was to examine the real-world impact of our proposed model of integrated parenting practices on under-resourced African American youth. We therefore examined parental perception of the direct and interactive effects of (culturally-specific) racial socialization messages and (universal) supportive parenting practices on behavioral outcomes in under-resourced African American youth. A community sample of 150 parents (mean age = 41.32, SD = 1.71) provided self-report responses regarding their use of supportive parenting behaviors, racial socialization messages and their observations of problem behaviors. Consistent with our hypotheses, supportive parenting was associated with fewer maladaptive child behaviors. Regression analyses indicated that the combination of racial pride messages and supportive parenting practices predicted parental reports of observed negative internalizing and externalizing behaviors. We discuss results in the context of their implications of our integrative model of racial socialization and supportive parenting in promoting adaptive functioning in under-resourced African American families.
Swelling agents and devices in oral drug delivery

Swelling agents are hydrophilic crosslinked polymers, which swell from 10 to 1,000 times their own weight when placed in an aqueous medium. Depending on their swelling properties, these materials have been exploited in developing three different classes of materials in pharmaceutical industries, i.e. swellable matrices, superdisintegrants and swelling devices. Since their development, these pharmaceutical excipients have found significant applications in drug delivery area. This review examines the properties of swelling agents and devices with the focus on drug delivery applications.
Laser beams and resonators: Beyond the 1960s

This paper describes the continuing advances in laser resonators and optical beam propagation that emerged in the decades following the 1960s, growing out of the fundamental concepts from that era reviewed in an earlier paper. It also presents a brief look forward at some of the continued innovations now emerging in these areas.
Hard-tissue ablation simulations using the LATIS computer code

A simulation code for analyzing laser matter interactions is described in the context of short pulse laser ablation of hard tissue. Some experimental results on short pulse laser absorption are presented and used to motivate employing such systems for ablating biological tissues. Results of simulations of hard tissue drilling are given, including hydrodynamic response and ablation efficiency.
Adaptive Bone Remodeling to Capture the Trabecular Bone Morphology of the Proximal Femur

In this study, a model of femur which resembles bone natural structure has been developed. The model initially consists of a solid shell representing cortical bone encompassing a cubical network of interconnected rods with circular cross-sections representing trabecular bone part. A computational efficient program has been developed which iteratively changes the structure of trabecular bone by keeping the local stress in the structure within a defined stress range. The stress is controlled by either enhancing existing beam elements or removing beams from the initial trabecular frame structure. Trabecular bone structure is obtained for two load cases: walking and stair climbing. The results show that as the magnitude of the loads increase, the internal structure gets denser in critical zones. The higher density is achieved using loading associated with the stair climbing. Walking which is considered as the routine daily activity, results in the less internal density in different regions of the bone. The results show that the converged bone architecture consisting of rods and plates are consistent with the natural bone morphology of femur. Furthermore, the bone volume fraction at the critical regions of the converged structure is in a good agreement with previously measured data obtained from combinations of Dual X-ray Absorptiometry (DXA) and Computed Tomography (CT).Copyright © 2014 by ASME
The Effect of Heat Generation on Low Cycle Fatigue Life Prediction

An energy-based life prediction method is used in this study to determine the fatigue life of tension-compression loaded components in the very low cycle regime between 102 and 104 . The theoretical model for the energy-based prediction method was developed from the concept that the strain energy accumulated during both monotonic failure and an entire fatigue process are equal; In other words, the scalar quantity of strain energy accumulated during monotonic failure is a physical damage quantity that correlates to fatigue as well. The energy-based method has been successfully applied to fatigue life prediction of components failing in the fatigue regime between 104 and 107 cycles. To assess Low Cycle Fatigue (LCF) with the prediction method, a clearer understanding of energy dissipation through heat, system vibration, damping, surface defects and acoustics were necessary. The first of these topics analyzed is heat. The analysis conducted studies the effect of heat generated during cyclic loading and heat loss from slipping at the interface of the grip wedges of the servo-hydraulic load frame and the test specimen. The reason for the latter is to address the notion that slippage in the experimental setup may be the cause of the reduction in the accuracy of the energy-based prediction method for LCF, which was seen in previous research. These analyses were conducted on Titanium 6Al-4V, where LCF experimental data for stress ratios R = −1 and R = −0.813 were compared with the energy-based life prediction method. The results show negligible effect on both total and cyclic energy from heat generation at the interface of the grip wedges and heat generation in the fatigue zone of the specimen.Copyright © 2011 by ASME
Investigation of the Gas-Diffusion-Electrode Used as Lithium/Air Cathode in Non-aqueous Electrolyte and the Importance of Carbon Material Porosity

The gas-diffusion-electrode used in a Li–air cell has been studied in a unique homemade electrochemical cell. Three major obstacles for the development of a feasible Li–air system were discussed with a focus on the development of a functional gas-diffusion-electrode in non-aqueous electrolytes and the way of avoiding the passivation of gas-diffusion-electrodes caused by the deposition of the reduction products. It is the first time that the importance of establishing the 3-phase electrochemical interface in non-aqueous electrolyte is demonstrated by creating air-diffusion paths and an air saturated portion for an air cathode. A model mechanism of electrode passivation by the reaction products was also proposed. Lithium oxides formed during O2 reduction tend to block small pores, preventing them from further utilization in the electrochemical reaction. On the other hand, lithium oxides would accumulate inside the large pores during the reduction until the density of oxides becomes high enough to choke-off the mass transfer. Carbon materials with a high surface area associated with larger pores should be selected to make the gas-diffusion-electrode for Li–air battery. For the first time, a near linear relationship between the capacity of GDE in a non-aqueous electrolyte and the average pore diameter was demonstrated, which could be used to estimate the capacity of the GDE quantitatively.
Property Devolution in Tuscany

Much of the historical demographic literature focuses on inheritance, and, in particular, how parents' transmission of land to their offspring facilitated their economic survival. Thus, inheritance practices are often linked to age of marriage and household structure. Analyses of the fifteenth-century notarial documents and tax declarations of smallholders in a region of Tuscany called the Val di Cecina illustrate the many forms of property devolution that these smallholders used and the different ways that they gained access to land through local markets. Given the high mortality rates that prevented a predictable transmission of property between the generations, the local markets, and the varieties of property devolution, inheritance may have been less important for economic survival and age of marriage in the Val di Cecina than in other regions, indicating the variability of inheritance in preindustrial settings.
Low temperature, high frequency permeability of Metglas 2714A and its potential for use as a core material for EMI filters

We report the measurement of the relative permeability of Metglas 2714A at 4.2 K temperature and at frequencies up to 1 MHz. We find that at ∼300 kHz, the real part of the relative permeability begins to drop towards unity, while the magnitude of the imaginary part increases. Our data can be used to design transformers and EMI filters for low temperature applications.
Artificial Propagation of Capillaria Obsignata in Chickens

Abstract GRAYBILL (1924) was the first to report Capillaria obsignata in the United States. He also reported embryonating the ova in shallow layers of physiological saline at 22 to 25 degrees C. Embryonation was complete in seven days in one instance and in six days in another. He did not attempt to infect chickens. Cram (1932), as corrected by Levine (1938), reported embryonation of ova after 42 days at 30 degrees C. When these ova were fed to a chicken and a quail, capillarids were found after 19 and 22 days, respectively. Levine (1936) used fly larva to digest the putrescible material from the feces of parasitized chickens and pigeons. When the putrescible material was digested, the majority of the larvae were removed. The residue was moistened and incubated and the ova subsequently embryonated. Levine was successful in infecting chickens by feeding this material. Shumard (1959) reported successful embryonation of ova …
Patterns of innervation of sympathetic vascular neurons by peptide-containing primary sensory fibers.

The purpose of this study was to determine whether there is a specific organization of the primary sensory innervation on to identified vascular neurons in the inferior mesenteric ganglion (IMG) in guinea-pig. Retrograde tracers were placed intraluminally in inferior mesenteric artery (IMA) or inferior mesenteric vein (IMV) in vitro to identify ganglionic neurons as arterial, venous or unlabeled neurons. The distribution of primary sensory nerve fibers containing calcitonin gene-related peptide (CGRP), neuronal nitric oxide synthase (NOS) and substance P immunoreactivity (SP-IR) was compared before and after treatment with capsaicin. In control animals the density of immunoreactivity varied both with the transmitter and the type of neuron innervated. The density of immunoreactivity for all the three substances was reduced by capsaicin treatment. The degree of reduction of immunoreactivity in the fibers varied with the transmitter and the type of neuron. The density of CGRP and SP immunoreactive fibers was greatest around unlabeled neurons; 78% of the CGRP fibers were of primary sensory origin and all of the SP fibers were primary sensory. Around arterial neurons 44% of the CGRP fibers were of primary sensory origin and around venous 68% were primary sensory. NOS positive innervation around venous neurons was denser than around arterial neurons and all of it was completely (97%) eliminated by capsaicin, indicating that it was solely of primary sensory origin. We conclude that the primary sensory fibers innervating the IMG are differentially distributed to arterial and venous neurons and that the pattern of distribution is characteristic for each sensory neurotransmitter.
Water and turf : Fluoridation and the 20th-century fate of waterworks engineers

Once central figures in American public health, waterworks engineers are no longer involved in many decisions made about the public water supplies. This paper argues that the profession's response to the early fluoridation movement of the 1940s and 1950s marked a change in the relationship between waterworks engineers and the other constitutive groups in public health and contributed to the disenfranchisement of the waterworks profession. Sensing a potentially divisive issue, two leaders of the profession, Abel Wolman and Linn Enslow, took steps they hoped would prevent a rift within the profession and allow waterworks engineering to continue its association with the wider public health community. Although the leaders saw the fluoridation issue differently, neither encouraged the profession to consider it openly or to take up the broader question of what limits, if any, should be placed on treating water supplies to meet human needs. Instead, they opted to locate authority for fluoridation outside the waterworks profession with dentists, doctors, and public health administrators. As a result, waterworks engineers conceded a great deal of the status and prestige associated with decision-making roles in community health issues and have largely faded from view.
Effects of Ethanol on Receptor-Mediated Endocytosis in the Liver

Abstract McVICKER, B. L. AND C. A. CASEY. Effects of ethanol on receptor-mediated endocytosis in the liver. ALCOHOL 19 (3) 255–260, 1999.—Ethanol administration impairs multiple aspects in the process of receptor-mediated endocytosis (RME) in the liver. Studies from our laboratory over the last 10 years have carefully examined RME by the hepatocyte-specific asialoglycoprotein receptor (ASGP-R). We have identified a time course for ethanol-induced defects in RME and established that many of the impairments occur initially in the centrilobular region of the liver and as early as one week after ethanol administration. Impaired intravesicular acidification in ethanol-fed animals has been identified, and these defects in acidification could alter multiple protein trafficking pathways including RME. In addition to altered acidification, altered receptor function (including receptor inactivation) could also contribute to impaired trafficking. Current studies in our laboratory are aimed at an examination of posttranslational modifications in the receptor (acylation and phosphorylation) that are known to affect its function. A role for the ASGP-R in the process of alcoholic apoptosis is also being examined because proper functioning of the ASGP-R is thought to be important in clearance of apoptotic cells.
Does corruption undermine trust in health care? Results from public opinion polls in Croatia

Health and health care provision are one of the most important topics in public policy, and often a highly debated topic in the political arena. The importance of considering trust in the health care sector is highlighted by studies showing that trust is associated, among others, with poor self-related health, and poorer health outcomes. Similarly, corruption has shown to create economic costs and inefficiencies in the health care sector. This is particularly important for a newly democratized country such as Croatia, where a policy responsive government indicates a high level of quality of democracy (Roberts, 2009) and where a legacy of corruption in the health care sector has been carried over from the previous regime. In this study, I assess the relationship between health care corruption and trust in public health care and hypothesize that experience with health care corruption as well as perception of corruption has a negative effect on trust in public care facilities. Data were collected in two surveys, administered in 2007 and 2009 in Croatia. Experience with corruption and salience with corruption has a negative effect on trust in public health care in the 2007 survey, but not in the 2009 survey. While the results are mixed, they point to the importance of further studying this relationship.
α7-Containing nicotinic receptors are segregated to the somatodendritic membrane of the cholinergic neurons in the avian nucleus semilunaris

Segregation of ion channels and neurotransmitter receptors is an important mechanism for determining the functionality of the nervous system. In the case of nicotinic acetylcholine receptors, electrophysiological and anatomical studies have demonstrated that these receptors can be located at the somatodendritic and the axon terminal portions of neurons. Functionally, somatodendritic nicotinic receptors mediate fast excitatory transmission and possibly regulate other cell functions, while presynaptic nicotinic receptors enhance the release of neurotransmitters from axon terminals. Neurons in the mesencephalic lateral spiriform nucleus of the chick do not appear to restrict the localization of nicotinic receptors to specific membrane compartments, since receptors containing alpha5 and/or beta2 subunits are found both on the cell bodies and on the axonal projections of these neurons [Torrao A. S. et al. (1996) Brain Res. 743, 154-161]. We report here that, in contrast to lateral spiriform neurons, neurons in the nucleus semilunaris do appear to compartmentalize nicotinic receptors. The cholinergic nucleus semilunaris neurons express a high density of alpha7-containing nicotinic receptors on their somas [Britto L. R. G. et al. (1992) J. comp. Neurol. 317, 325-340]. However, when we examined the projections of these neurons in the lateral spiriform nucleus, we found no evidence for expression of alpha7-containing receptors on the cholinergic fibers from nucleus semilunaris neurons. Furthermore, patch-clamp electrophysiological recording from lateral spiriform neurons indicated an absence of presynaptic alpha7-containing nicotinic receptors capable of modulating the release of acetylcholine. We conclude that neurons are capable of segregating alpha7-containing nicotinic receptors to specific areas of their plasma membrane. Such targeting of nicotinic receptors would play an important role in determining their functional role in neurons.
Implications for Ultrafast Reflection Electron Diffraction from Temporal and Spatial Evolution of Transient Electric Fields

Understanding interaction of ultrafast pulsed laser with matter is critical for probing ultrafast processes in materials science, understanding the physics of laser ablation and the laser induced non-equilibrium carrier dynamics in metals and semiconductors, including plasmonics. When an intense laser pulse of femtoseconds (fs) in duration hits the surface of a targeted matter, it excites a hot electron gas. Part of the hot electrons is emitted from the surface in a way similar to thermionic emission. Electrons can also be emitted through multiphoton photoemission (MPPE) or thermally assisted MPPE. The emitted electrons travel at speeds that create transient electric fields (TEFs). To detect TEFs and study the dynamics of emitted electrons, we have developed a time resolved electron beam imaging technique that allows us to measure TEFs above a sample surface at picoseconds time resolution. We have also developed a model of the TEFs based on the propagation of emitted electrons and the percentage of electrons escaping from the surface. We examine the significance of TEFs for ultrafast reflection electron diffraction by examining anomalous effects in ultrafast reflection high energy electron diffraction (RHEED) of silicon surfaces.
Nondegenerate Continuation Problems for the Excitation Response of Nonlinear Beam Structures

This paper investigates the dynamics of a slender beam subjected to transverse periodic excitation. Of particular interest is the formulation of nondegenerate continuation problems that may be analyzed numerically, in order to explore the parameter-dependence of the steady-state excitation response, while accounting for geometric nonlinearities. Several candidate formulations are presented, including finite-difference (FD) and finite-element (FE) discretizations of the governing scalar, integro-partial differential boundary-value problem (BVP), as well as of a corresponding first-order-in-space, mixed formulation. As an example, a periodic BVP — obtained from a Galerkin-type, FE discretization with continuously differentiable, piecewise-polynomial trial and test functions, and an elimination of Lagrange multipliers associated with spatial boundary conditions — is analyzed to determine the beam response via numerical continuation using a MATLAB-based software suite. In the case of an FE discretization of the mixed formulation with continuous, piecewise-polynomial trial and test functions, it is shown that the choice of spatial boundary conditions may render the resultant index-1, differential-algebraic BVP equivariant under a symmetry group of state-space translations. The paper demonstrates several methods for breaking the equivariance in order to obtain a nondegenerate continuation problem, including a projection onto a symmetry-reduced state space or the introduction of an artificial continuation parameter. As is further demonstrated, an orthogonal collocation discretization in time of the BVP gives rise to ghost solutions, corresponding to arbitrary drift in the algebraic variables. This singularity is resolved by using an asymmetric discretization in time.© 2013 ASME
Mediation with a focus on discursive positioning

This article advances some alternative theoretical bases for understanding conflict and building mediation practice on the basis of constructionist social theory in general and on positioning theory in particular. It outlines some goals for a narrative practice in mediation that are distinctive from existing models of mediation.
Observations on the distribution of amine oxidase in invertebrates.

Abstract 1. 1. The tissues of some species of marine invertebrates have been examined for amine oxidase activity. 2. 2. The enzyme has been found in many, but not all, mollusks; in echinoderms it was found in all asteroids and echinoids, but not in Holothuria . The enzyme was also found in an annelid worm, Chaetopterus variopedatus . 3. 3. No enzymic activity could be demonstrated in three species of tunicates examined.
Further studies on the influence of genotype and dietary protein on the performance of broilers

Abstract An experiment was conducted to quantify genetic differences in response to dietary protein level of male vs female broilers. Broilers (1 d old) from a “high-yield” strain cross (Ross x Ross 208) and a “fast-growing” strain cross (Peterson x Arbor Acres) were placed on fresh pine shavings in floor pens. From Day 0 to 18, all birds were fed a 23% CP starter diet. During Days 18 to 53 male birds were fed either a 16, 18, 20, 22, 24, or 26% CP diet (3,200 kcal ME/kg) and female birds were fed the 16, 20, or 24% CP diet. Significant differences (P
Operational derivation of wave functions for a symmetrical rigid rotator

Abstract An operational procedure is presented for obtaining the normalized eigenfunctions Ψ(JKM) of a rigid symmetrical rotator and the matrix elements of the rectangular components of its angular momentum in both body-fixed and space-fixed axes.
Random transitions, size control, and inheritance in cell population dynamics

Abstract A general model of cell population dynamics is derived and analyzed. The model uses the continuous structure variables age and size, and thus distinguishes individual cells with respect to such properties as cycle length and division size. The model allows the occurrence of random transitions as cells progress through the cell cycle, the control of cell size upon cell cycle events, and the inheritance of properties from mother to daughter cells. The concepts of asynchronous exponential growth, α-curves, β-curves, mother-daughter transit time correlations, and sister-sister transit time correlations are formalized. The existence and uniqueness of solutions to the model is proved.
Evaluation of the Enantiomeric Separation of Dipeptides Using a Chiral Crown Ether LC Column

Abstract The direct optical resolution of six dipeptides into four stereoisomers each was achieved on an enantioselective crown ether column. An inclusion complex is formed between the stationary phase and the solute when using an acidic mobile phase. The acidic mobile phase serves to protonate the requisite primary amine of the dipeptide thereby allowing an attractive interaction between the ammonium functional group and the oxygens of the crown ether. Due to the differences in stability of the complexes formed, the four optical isomers elute at different times allowing the stereoisomeric separation. One of the factors affecting enantioselectivity is the distance between the primary amine functional group and the stereogenic center of the chiral moiety. Dipeptides are particularly useful molecules for the studying this “distance effect” since the bonding order of the two amino acids can be reversed. In addition to the enantiomeric separations of dipeptides possessing two stereogenic centers, the behavior...
Search for excited muons

We have searched for the production of excited muons via a missing-mass analysis of the spectrum of recoil protons emitted when muons interact in liquid hydrogen. No evidence is seen for the production of an excited muon of mass between 0.0 and 2.0 GeV.
Antiviral therapy reduces risk of hepatocellular carcinoma in patients with hepatitis C virus-related cirrhosis.

Background & Aims The effects of antiviral therapy on prevention of hepatocellular carcinoma (HCC) in patients with hepatitis C virus (HCV)-related cirrhosis are unclear. We performed a systematic review and meta-analysis to assess HCC risk reduction in patients with HCV-related cirrhosis who have received antiviral therapy. Methods Twenty studies (4700 patients) were analyzed that compared untreated patients with those given interferon (IFN) alone or ribavirin. Risk ratios (RRs) determined effect size using a random effects model. Results Pooled data showed reduced HCC risk in the treatment group (RR, 0.43; 95% confidence interval [CI], 0.33–0.56), although the data were heterogenous (χ2 = 59.10). Meta-regression analysis showed that studies with follow-up durations of more than 5 years contributed to heterogeneity. Analysis of 14 studies (n = 3310) reporting sustained virologic response (SVR) rates with antiviral treatment showed reduced HCC risk in patients with an SVR, compared with nonresponders (RR, 0.35; 95% CI, 0.26–0.46); the maximum benefits were observed in patients treated with ribavirin-based regimens (RR, 0.25; 95% CI, 0.14–0.46). Meta-analysis of 4 studies assessing the role of maintenance IFN in nonresponders did not show HCC risk reduction (RR, 0.58; 95% CI, 0.33–1.03). No publication bias was detected by the Egger test analysis (P > 0.1). Conclusions The risk of HCC is reduced among patients with HCV who achieve an SVR with antiviral therapy. Maintenance therapy with IFN does not reduce HCC risk among patients who do not respond to initial therapy. View this article's video abstract atwww.cghjournal.org.
Evaluation of the use of prairie grasses for stimulating polycyclic aromatic hydrocarbon treatment in soil

Abstract A research project was conducted to evaluate enhanced treatment of toxic organic chemicals in soil using deep rooted grasses. Eight types of prairie grasses were evaluated in the treatment of four polycyclic aromatic hydrocarbons (PAHs) in a sandy loam soil. The extent of PAH disappearance in vegetated soil was significantly greater than in unvegetated soil.
Effect of Equatorial Ring Current on Cosmic-Ray Intensity

The equatorial ring current postulated by Chapman and Ferraro to explain the main phase of terrestrial magnetic storms is analyzed with respect to its effect on the intensity of the cosmic radiation. For mathematical convenience, the ring current is replaced by a current sheet located on the surface of a sphere concentric with the earth, in accordance with a suggestion due to Chapman. A simple expression is then obtained relating the variations in magnetic field at the equator with the corresponding variations to be expected in the intensity of cosmic radiation measured by an arbitrary detector located at any latitude and atmospheric depth.
Genetic Malformations of the Human Cerebral Cortex

The author thanks J. Joseph, G. Holmes, M. Berg, and E. Miyawaki for providing figures; T. Chae, W. B. Dobyns, J. Gleeson, G. Mochida, and E. Monuki for thoughtful comments on the manuscript; and W. B. D. and members of the Walsh lab for many stimulating discussions about human malformations. Assistance with the preparation of the figures came from Katie Lee. Research in the author’s lab is supported by grants from the Human Frontier Science Program, the NINDS (RO1 NS35129, RO1 NS32457, RO1 NS38097, and PO1 NS38289), the National Alliance for Autism Research, the National Alliance for Research in Schizophrenia and Depression, and the Mental Retardation Research Center at Children’s Hospital, Boston.
A continuous culture apparatus for the mass production of algae

Abstract A multi-stage, continuous culture apparatus has been designed and tested for the production of algae for larval molluscs and crustacea. A single-line system produced a maximum of 2.4 × 10 11 cells/day, or 5 g ash-free dry weight of Monochrysis lutheri . Multiple-line systems are recommended for hatcheries. The flow rate affected algal cell density, yield, biomass, protein level, and residual nitrate. Maximal cell yield occurred at 10 I flow per day, a dilution rate of 63% of the volume of the first growth carboy, or 30% of the volume of the total system. The system is also adaptable to growth of larger planktonic algae or mixed cultures of algae and protozoa and/or rotifers.
Cloud Type and Macrophysical Property Retrieval Using Multiple Remote Sensors

A cloud detection algorithm based on ground-based remote sensors has been developed that can differentiate among various atmospheric targets such as ice and water clouds, virga, precipitation, and aerosol layers. Standard cloud type and macrophysical properties are identified by combining polarization lidar, millimeter-wave radar, infrared radiometer, and dual-channel microwave radiometer measurements. These algorithms are applied to measurements collected during 1998 from the Atmospheric Radiation Measurement Program Cloud and Radiation Test Bed site in north-central Oklahoma. The statistical properties of clouds for this year are presented, illustrating how extended-time remote sensing datasets can be converted to cloud properties of concern to climate research.
Assessment Practices and the Underrepresentation of Minority Students in Gifted and Talented Education

Several scholars have asserted that the underrepresentation of minority students in gifted and talented education (GATE) programs is the result of biased assessment practices. However, an examinati...
Plasma nitrite response in older women to a physical function test.

Background and aims: Nitric oxide (NO) may play a critical role in facilitating the delivery of blood to active skeletal muscle, ultimately impacting functional health in older adults. Plasma nitrite is a useful marker of vascular NO bioavailability. The aim of the current investigation was to examine the effect of a widely used physical function test on plasma nitrite concentrations in older adults. Methods: Venous blood was drawn before, immediately following, and 10 minutes following the completion of a 400-m walk test. Blood samples were added to heparin and frozen for subsequent analysis of nitrite levels using chemiluminescence. Results: Twenty six (79±4 yrs) women participated in this study. Plasma nitrite levels decreased approximately 22% from baseline following a 400-m walk. Percent change in plasma nitrite was related to walking speed (r=−0.550, p=0.004). Conclusions: These data suggest an alteration in plasma nitrite concentration following a functional test which may impact functional health.
Assessing Observer Agreement in Studies Involving Replicated Binary Observations

We propose a new approach to evaluating agreement between two observers making binary observations on a set of subjects. This approach compares the probability of disagreement (or discordance) between the observers to the probability of disagreement between replicated observations made by the same observer on the same subject. We consider two situations: (1) a symmetric assessment of agreement between two observers, and (2) an assessment of the agreement of a new observer with an imperfect “gold standard”. We develop a nonparametric method for estimation of the new agreement coefficients when observers make replicated readings on each subject. The reliability of the estimation method is examined via a simulation study. Data from a study aimed at determining the validity of diagnosis of breast cancer based on mammograms is used to illustrate the new concepts and methods.
A Randomized Assessment of the Incremental Role of Ablation of Complex Fractionated Atrial Electrograms After Antral Pulmonary Vein Isolation for Long-Lasting Persistent Atrial Fibrillation

Objectives This study sought to determine whether ablation of complex fractionated atrial electrograms (CFAEs) after antral pulmonary vein isolation (APVI) further improves the clinical outcome of APVI in patients with long-lasting persistent atrial fibrillation (AF). Background Ablation of CFAEs has been reported to eliminate persistent AF. However, residual pulmonary vein arrhythmogenicity is a common mechanism of recurrence. Methods In this randomized study, 119 consecutive patients (mean age 60 ± 9 years) with long-lasting persistent AF underwent APVI with an irrigated-tip radiofrequency ablation catheter. Antral pulmonary vein isolation resulted in termination of AF in 19 of 119 patients (Group A, 16%). The remaining 100 patients who still were in AF were randomized to no further ablation and underwent cardioversion (Group B, n = 50) or to ablation of CFAEs in the left atrium or coronary sinus for up to 2 additional hours of procedure duration (Group C, n = 50). Results Atrial fibrillation terminated during ablation of CFAEs in 9 of 50 patients (18%) in Group C. At 10 ± 3 months after a single ablation procedure, 18 of 50 (36%) in Group B and 17 of 50 (34%) in Group C were in sinus rhythm without antiarrhythmic drugs (p = 0.84). In Group A, 15 of 19 patients (79%) were in sinus rhythm. A repeat ablation procedure was performed in 34 of 100 randomized patients (for AF in 30 and atrial flutter in 4). At 9 ± 4 months after the final procedure, 34 of 50 (68%) in Group B and 30 of 50 (60%) in Group C were in sinus rhythm without antiarrhythmic drugs (p = 0.40). Conclusions Up to 2 h of additional ablation of CFAEs after APVI does not appear to improve clinical outcomes in patients with long-lasting persistent AF.
Performance of silicone-coated polymeric membrane in separation of hydrocarbons and nitrogen mixtures

Abstract This study reports selectivities and permeances of pure nitrogen, oxygen, ethylene, ethane, propylene and propane and their mixtures through composite poly(dimethylsiloxane) (PDMS)–polysulfone membrane at ambient temperature. It was observed that both propylene and/or propane significantly plasticized PDMS coating in pure as well as mixed gas permeation experiments. Above the plasticization pressure, the permeance order was P C 3 > P C 3 > P C 2 > P C 2 > P O 2 > P N 2 , which matched the solubility order. However, permeance order was changed to P C 3 > P C 3 > P C 2 > P C 2 > P O 2 > P N 2 below the plasticization pressure, showing that propylene was more permeable than propane. Furthermore, plasticization caused coupling effects for ethylene, ethane and nitrogen in the presence of propylene and propane.
Stress dependence of the charge-density-wave transitions in Nb Se 3 and Ta S 3

We have measured the change in the charge-density-wave (CDW) transitions in monoclinic Nb${\mathrm{Se}}_{3}$ and orthorhombic Ta${\mathrm{S}}_{3}$ caused by stress applied along the high-symmetry (growth) axis. For the upper transition in Nb${\mathrm{Se}}_{3}$, $\frac{d{T}_{1}}{d\ensuremath{\sigma}}=\ensuremath{-}4.4$ K/GPa for stresses up to 5 GPa, the increase in the resistance due to the transition, $\ensuremath{\Delta}R$, is almost unaffected, and the critical field for motion of the CDW, ${E}_{c}$, increases with stress. For the lower transition in Nb${\mathrm{Se}}_{3}$, $\frac{d{T}_{2}}{d\ensuremath{\sigma}}=\ensuremath{-}0.4$ K/GPa, $\ensuremath{\Delta}R$ more than doubles at 5 GPa, and ${E}_{c}$ is relatively unaffected. The 222-K transition in Ta${\mathrm{S}}_{3}$ decreases at a rate of -15 K/GPa for low stresses. At stresses above 2.5 GPa the resistance of Ta${\mathrm{S}}_{3}$ begins to increase again, possibly due to a second stress-induced CDW transition. Both thermal hysteresis and stress hysteresis are seen in Ta${\mathrm{S}}_{3}$ between about 100 and 200 K.
Pomegranate phytoconstituents blunt the inflammatory cascade in a chemically induced rodent model of hepatocellular carcinogenesis

Liver cancer, predominantly hepatocellular carcinoma (HCC), represents a complex and fatal malignancy driven primarily by oxidative stress and inflammation. Due to dismal prognosis and limited therapeutic intervention, chemoprevention has emerged as a viable approach to reduce the morbidity and mortality of HCC. Pomegranate fruit is a rich source of phytochemicals endowed with potent antioxidant and anti-inflammatory properties. We previously reported that pomegranate phytochemicals inhibit diethylnitrosamine (DENA)-initiated hepatocarcinogenesis in rats though nuclear factor E2-related factor 2 (Nrf2)-mediated antioxidant mechanisms. Since Nrf2 also acts as a key mediator of the nuclear factor-kappaB (NF-κB)-regulated inflammatory pathway, our present study investigated the anti-inflammatory mechanisms of a pomegranate emulsion (PE) during DENA-induced rat hepatocarcinogenesis. Rats were administered with PE (1 or 10 g/kg) 4 weeks before and 18 weeks following DENA initiation. There was a significant increase in hepatic expressions of inducible nitric oxide synthase, 3-nitrotyrosine, heat shock protein 70 and 90, cyclooxygenase-2 and NF-κB in DENA-exposed rat livers. PE dose-dependently suppressed all aforementioned elevated inflammatory markers. A conspicuous finding of this study involves lack of cardiotoxicity of PE as assessed by monitoring cardiac function using noninvasive echocardiography. Our results provide substantial evidence that suppression of the inflammatory cascade through modulation of NF-κB signaling pathway may represent a novel mechanism of liver tumor inhibitory effects of PE against experimental hepatocarcinogenesis. Data presented here coupled with those of our earlier study underline the importance of simultaneously targeting two interconnected molecular circuits, namely, Nrf2-mediated redox signaling and NF-κB-regulated inflammatory pathway, by pomegranate phytoconstituents to achieve chemoprevention of HCC.
Immersive chemistry video game

A team at Purdue University has been working on a NSF sponsored project to create a set of research-validated recommendations for the development of science video games. As a way to accomplish this task, the team created a three-dimensional first-person shooter video game that requires players to utilize chemistry knowledge to advance in the game-world. A team of chemistry, computer graphics technology, computer science, and instructional designers collaborated in the development of the game and in conducting the research. This paper details the process used by the team. Results from human subject testing will be presented at the conference.
Effect of Jammer on the Performance of OFDM In the Presence of Nonlinearity In Rayleigh Fading Channel with Application to 802.11n WLAN

In this paper, we present the performance analysis of an equalized OFDM system that is subject to nonlinear distortions from a high power amplifier (HPA), narrowband jamming interference and imperfect channel estimation in a Rayleigh fading channel. The analytical model is then extended to the Wireless Local Area Network (WLAN) system that is implemented based on IEEE 802.11n standard. Finally, the simulation results obtained from the extended model based on various sets of parameters are compared with the theoretical results.