cssi/SciSciGPT-SciSciNet huggingface dataset:
The content and size distribution of membrane-bound and free polyribosomes in mouse liver during aging

The method of Ramsey and Steele [Anal. Biochem., 92 (1979) 305--313] was used to examine the size distribution of membrane-bound and free polyribosomes from the liver of male C57 BL/6 mice over the life span. Optimization of the concentration of Mg2+ and liver cell sap suppressed breakdown by ribonuclease and presumably gave preparations that approximate the integrity of native polyribosome populations. The content of polysomes per unit liver tissue from 7 groups of fed mice aged 10--35 months showed an age-related increase of subunits and monomers (+54%) and dimers-to-pentamers (+76%) in membrane-bound polyribosomes. The dimer-to-pentamer class of free polyribosomes also increased (+52%). Polysomes larger than nonamers showed 13% and 21% decreases that were not statistically significant. Total tissue ribosomes increased 15%, while the membrane-bound/free polyribosome ratio remained nearly constant at about 1.15. In a subsequent study, both 6 h-fasted and fed mice showed decreases (-20% to -33%) in membrane-bound and free polyribosomes larger than nonamers during aging from 15 to 35 months. The dimer-to-pentamer class of free polyribosomes in fed mice increased (+26%), while this class in the other groups underwent increases (+26 to +39%) that were not statistically significant. We conclude that the liver in old mice is not obviously deficient in either quantity or general quality of ribosomes. Old animals do tend to show an increase in small polysomes and a decrease in large polysomes, which is consistent with a reduction in the rate of translation.
Modeling styrene-styrene interactions.

This study is the first step in the systematic investigation of substituted (carboxyl) polystyrene nanoparticles. Understanding the fundamental interactions between the p-carboxyl styrene monomers, where an ethyl group is used instead of a vinyl group (referenced, for convenience, as "p-carboxyl styrene"), provides the basic information needed to construct potentials for nanoparticles composed of these monomers. In this work, low-energy isomers of p-carboxyl styrene dimer were studied. The dimer structures and their relative and binding energies were determined using both Moller-Plesset second-order perturbation theory (MP2) and the general effective fragment potential (EFP2) method. Sections of the intermolecular potential energy surface (PES) of the p-carboxylated styrene dimer in its global minimum orientation were also determined. As expected, double hydrogen bonding between the two carboxylic groups provides the strongest interaction in this system, followed by isomers with a single H-bond and strong benzene ring-benzene ring (pi-pi) type interactions. Generally, the EFP2 method reproduces the MP2 geometries and relative energies with good accuracy, so it appears to be an efficient alternative to the correlated ab initio methods, which are too computationally demanding to be routinely used in the study of the more-complex polymeric systems of interest.
A direct fourier approach for the analysis of thin finite-dimensional cylindrical panels

Abstract A hitherto unavailable Fourier series solution to the boundary-value problem of thin cylindrical panels of rectangular planform, subjected to transverse loads, is presented. Sanders' kinematic relations (for classical shell theory) are utilized in the formulation, which generates one fourth-order (in terms of the transverse displacement component) and two second-order (in terms of the surface-parallel displacement components) partial differential equations with constant coefficients. A boundary-discontinuous double Fourier series approach is used to solve the system of three partial differential equations with the SS2-type simply-supported boundary conditions prescribed at all four edges. The final algebraic equations are expressed in terms of the boundary Fourier coefficients, which substantially reduce the size of the matrix, that is inverted using a digital computer. The accuracy of the series solution is ascertained by studying the convergence characteristics, and also by comparison with finite element solutions. Other important numerical results presented include variation of displacement and moment with the radius-to-thickness, length-to-thickness and length-to-width ratios. Also presented are variations of displacement and moment along the center line of the cylindrical panels. These numerical results contribute to our understanding of the complex deformation behavior of finite cylindrically curved panels—especially the influence of the boundary discontinuities on the computed displacements and stresses.
A kinetic and structural characterization of adenosine-5'-triphosphate: ribonucleic acid adenylyltransferase from Pseudomonas putida.

Abstract A catalytic and structural study of ATP:RNA adenylyltransferase (EC 2.7.7.19) from the particulate fraction of Pseudomonas putida was made. During the large-scale purification of this enzyme, designated adenylyltransferase B, a previously undetected ATP-incorporating activity, designated adenylyltransferase A, was observed. Adenylyltransferases A and B were indistinguishable catalytically; however, they differed in their chromatographic and sedimentation properties. Adenylyltransferases A and B were resolved by phosphocellulose, by poly(U)-Sepharose and by Bio-Gel P-100 chromatographies. Adenylyltransferase A was determined to have a sedimentation coefficient (s020, w) of 9.3 S and B of 4.3 S. The molecular weight of adenylyltransferase A was estimated to be 185 000 and that of adenylyltransferase B to be 50 000–60 000. Apparently, adenylyltransferase A was generated from adenylyltransferase B during the purification. The AMP incorporation catalyzed by adenylyltransferases A and B was inhibited by two derivatives of the antibiotic rifamycin, AF 013 (50% at 5 μg/ml) and AF DNFI (50% at 10 μg/ml). The 5′-triphosphate derivative (3′-dATP) of the drug cordycepin (3′-deoxyadenosine) was a competitive inhibitor with ATP for both adenylyltransferases. The Km for 3′-deoxyadenosine 5′-triphosphate was 6 · 10−4–10 · 10−4 M, while the Km for ATP was 1 · 10−4–2 · 10−4 M. Several other analogs of ATP, 2′-deoxyadenosine 5′ triphosphate, 2′-O-methyl ATP, or the fluorescent 3-β-D-ribofuranosylimidazo [2,1-i] purine 5′-triphosphate did not affect the activity of adenylyltransferase A or B. Poly(U) and poly(dT) were competitive inhibitors of the ribosomal RNA-primed polymerization reaction. The Km for poly(U) or poly(dT), in terms of nucleotide phosphate, was 4 · 10−6–10 · 10−6 M for the Km of ribosomal RNA. The inhibition was a result of the competition between the non-priming poly(U), or poly(dT), and ribosomal RNA for the primer binding site on the enzyme.
Bupivacaine is an effective potassium channel blocker in heart

The local anesthetic agent bupivacaine increases action potential duration in isolated frog atrial myocytes, and blocks two potassium conductances, IK and IK1. The effective concentrations, particularly for IK, are similar to those which depress the sodium conductance. Potassium channel block may thus contribute to bupivacaine's reported cardiotoxicity.
A dolphin peripheral blood leukocyte cDNA microarray for studies of immune function and stress reactions.

A microarray focused on stress response and immune function genes of the bottlenosed dolphin has been developed. Random expressed sequence tags (ESTs) were isolated and sequenced from two dolphin peripheral blood leukocyte (PBL) cDNA libraries biased towards T- and B-cell gene expression by stimulation with IL-2 and LPS, respectively. A total of 2784 clones were sequenced and contig analysis yielded 1343 unigenes (archived and annotated at www.marinegenomics.org). In addition, 52 dolphin genes known to be important in innate and adaptive immune function and stress responses of terrestrial mammals were specifically targeted, cloned and added to the unigene collection. The set of dolphin sequences printed on a cDNA microarray comprised the 1343 unigenes, the 52 targeted genes and 2305 randomly selected (but unsequenced) EST clones. This set was printed in duplicate spots, side by side, and in two replicates per slide, such that the total number of features per microarray slide was 19,200, including controls. The dolphin arrays were validated and transcriptomic profiles were generated using PBL from a wild dolphin, a captive dolphin and dolphin skin cells. The results demonstrate that the array is a reproducible and informative tool for assessing differential gene expression in dolphin PBL and in other tissues.
An overlay algorithm to improve the support of multi-hopping in the IEEE 802.11 WLANs

Previous studies have argued that the performance of the IEEE 802.11 protocol is poor when used as a platform to implement multi-hop ad hoc networks. In this paper, we analyze the negative behavior caused by having multiple overlapping IBSSs (independent basic service sets) operating at the same frequency channel in an 802.11 ad hoc network. We propose an overlay algorithm on top of 802.11 to help discipline the interaction of overlapping IBSSs. Our algorithm yields noticeable improvement in the aggregate normalized throughput value per IBSS as well as the stability of the system.
Household Income during Childhood and Young Adult Weight Status Evidence from a Nutrition Transition Setting

This article explores whether household income at different stages of childhood is associated with weight status in early adulthood in a nutrition transition setting (a developing country with both...
Effects of inertia on the deformation of liquid drops in simple shear flow

Abstract Simple shear flow past a one-dimensional array of two-dimensional viscous drops with constant surface tension at small and moderate Reynolds numbers up to Re = 100 is considered in a Couette flow device. The deformation of the drops from the initial circular shape is computed using a variation of Peskin's immersed boundary formulation in conjunction with a finite-difference method for solving the equations of two-dimensional incompressible Newtonian flow. The results establish critical capillary and Weber numbers for large elongation and breakup as functions of the Reynolds number. When the physical properties of the drops are fixed, inertial effects tend to promote drop deformation. The kinematic structure of the flow is discussed with reference to eddy formation, distribution of wall shear stress, drag force exerted on the walls, and vorticity production at the interface.
Fluctuation-dissipation considerations and damping models for ferromagnetic materials

The role of fluctuation-dissipation relations (theorems) for the magnetization dynamics with Landau-Lifshitz-Gilbert and Bloch-Bloembergen damping terms are discussed. We demonstrate that the use of the Callen-Welton fluctuation-dissipation theorem, which was proven for Hamiltonian systems, can give an inconsistent result for magnetic systems with dissipation.
SEMARTCam scheduler: semantics driven real-time data collection from indoor camera networks to maximize event detection

A distributed camera network allows for many compelling applications such as large-scale tracking or event detection. In most practical systems, resources are constrained. Although one would like to probe every camera at every time instant and store every frame, this is simply not feasible. Constraints arise from network bandwidth restrictions, I/O and disk usage from writing images, and CPU usage needed to extract features from the images. Assume that, due to resource constraints, only a subset of sensors can be probed at any given time unit. This paper examines the problem of selecting the "best" subset of sensors to probe under some user-specified objective--e.g., detecting as much motion as possible. With this objective, we would like to probe a camera when we expect motion, but would not like to waste resources on a non-active camera. The main idea behind our approach is the use of sensor semantics to guide the scheduling of resources. We learn a dynamic probabilistic model of motion correlations between cameras, and use the model to guide resource allocation for our sensor network. Although previous work has leveraged probabilistic models for sensor-scheduling, our work is distinct in its focus on real-time building-monitoring using a camera network. We validate our approach on a sensor network of a dozen cameras spread throughout a university building, recording measurements of unscripted human activity over a two week period. We automatically learnt a semantic model of typical behaviors, and show that one can significantly improve efficiency of resource allocation by exploiting this model.
A Continuum Theory of Deformable, Semiconducting Ferroelectrics

Ferroelectric solids, especially ferroelectric perovskites, are widely used as sensors, actuators, filters, memory devices, and optical components. While these have traditionally been treated as insulators, they are in reality wide-band-gap semiconductors. This semiconducting behavior affects the microstructures or domain patterns of the ferroelectric material and the interaction of ferroelectrics with electrodes, and is affected significantly by defects and dopants. In this paper, we develop a continuum theory of deformable, semiconducting ferroelectrics. A key idea is to introduce space charges and dopant density as field (state) variables in addition to polarization and deformation. We demonstrate the theory by studying oxygen vacancies in barium titanate. We find the formation of depletion layers, regions of depleted electrons, and a large electric field at the ferroelectric–electrode boundary. We also find the formation of a charge double layer and a large electric field across 90° domain walls but not across 180° domain walls. We show that these internal electric fields can give rise to a redistribution or forced diffusion of oxygen vacancies, which provides a mechanism for aging of ferroelectric materials.
Examining Heterogeneous Patterns of Electronic Health Records Use: A Contingency Perspective and Assessment

The basic use of Electronic Health Records EHR and the progression toward advanced EHR applications are key concerns facing leaders interested in integrating the healthcare delivery supply chain. Currently, substantial heterogeneity exists among hospitals in terms of EHR use and the progression toward advanced EHR applications. Understanding this heterogeneity is important as hospitals face pressure to adopt and achieve meaningful use of the technology. Contingency theory is tested herein to suggest that a hospital's structural constraints may explain the heterogeneity among hospitals in terms of their EHR use. Data collected from 297 acute care hospitals in 47 states reveals that critical access hospitals may be slow to use EHR, even in basic applications. Conversely, major teaching hospitals appear to be early adopters, achieving advanced EHR use. These findings are important for hospital executives, Health Information Technology managers, and policymakers concerned with directing resources with an aim toward EHR integration.
UNDERSTANDING BUSINESS CYCLES

Why is it that, in capitalist economies, aggregate variables undergo repeated fluctuations about trend, all of essentially the same character? Prior to Keynes’ General Theory, the resolution of this question was regarded as one of the main outstanding challenges to economic research, and attempts to meet this challenge were called business cycle theory. Moreover, among the interwar business cycle theorists, there was wide agreement as to what it would mean to solve this problem. To cite Hayek, as a leading example: [T]he incorporation of cyclical phenomena into the system of economic equilibrium theory, with which they are in apparent contradiction, remains the crucial problem of Trade Cycle Theory;2 By ‘equilibrium theory’ we here primarily understand the modern theory of the general interdependence of all economic quantities, which has been most perfectly expressed by the Lausanne School of theoretical economics.3
vCRM: virtual customer relationship management

Virtual worlds provide companies opportunities for valuable co-creation and co-production with their customers. In order to harness this potential, companies need to design effective entry strategies for virtual customer relationship management or vCRM. Understanding how self-expression and collaboration work in virtual worlds can help design better customer-facing strategies. In this paper, we provide a roadmap for companies that want to leverage virtual worlds for vCRM.
Reciprocal Strategies for Large Groups

Reciprocal strategies have been shown to be effective in inducing long-term cooperation in social dilemmas involving small, but not large, groups. In this article, we argue that group-based reciprocal strategies (GBRS)—under which one reciprocates cooperative factions, not individuals, within the group—can induce cooperation in large groups. Results of two computer simulations of 100-member groups show that a GBRS accumulates a significantly larger payoff than do other commonly advocated mixedmotive strategies. A third simulation showed that the size of the cooperative faction is influenced by the nature of the payoff matrix; when there is considerable temptation to defect, one should cooperate only after a large number of others have done so, but if there is little temptation to defect, one should reciprocate the cooperative actions of a smaller faction. We also found that the use of a “win-cooperate, lose-defect” heuristic led to substantial total outcomes. Our results suggest several psychological fact...
Energy metabolism in the brains of L-phenylalanine-treated chicks.

— When day-old chicks were injected intraperitoneally with 1.62mmoles of l-phenylalanine, they developed a condition resembling narcosis. Simultaneously, whole brain levels of phenylalanine were 2–4 μmol/g, whereas those in control brain were 0.06 μmol/g. Examination of some glycolytic intermediates in the brain revealed significant decreases in fructose-1,6-diphosphate, l-α-glycerol phosphate and lactate, in comparison to the levels of these compounds in the saline-injected control animals. Levels of glucose and glucose-6-phosphate either increased or did not change, whereas levels of glycogen did not differ significantly. Phosphocreatine increased reciprocally with the decrease in inorganic phosphate. The levels of adenine nucleotide (energy charge) were not affected. Utilization of cerebral high-energy phosphates was depressed by 50–70 per cent when determined as a function of metabolic rate in the brain at 15- and 30-s periods of ischaemia according to the ‘closed-system’ technique. Explanations for these data have been examined, such as toxicity of phenylacetate and inhibition of glycolytic enzymes by phenylpyruvate and l-phenylalanine and their relevance to this study is discussed.
What are the advantages and disadvantages of imaging modalities to diagnose wear-related corrosion problems?

Background Adverse tissue reactions are known to occur after total hip arthroplasty using both conventional and metal-on-metal (MoM) bearings and after MoM hip resurfacing arthroplasty (SRA). A variety of imaging tools, including ultrasound (US), CT, and MRI, have been used to diagnose problems associated with wear after MoM hip arthroplasty and corrosion at the head-trunnion junction; however, the relative advantages and disadvantages of each remain a source of controversy.
FMCSA's medical review board: five years of progress in commercial driver medical examinations.

OBJECTIVE:: To revise and update guidance recommendations to the Federal Motor Carrier Safety Administration for evaluating commercial drivers. METHODS:: The Federal Motor Carrier Safety Administration's medical review board has addressed guidance for commercial drivers for the past 5 years. The processes for most topics involve comprehensive literature searches, evidence reports, medical expert panel reports, critique of the literature, testimony, and decision making. RESULTS:: No quality literature evaluating risk of crash among commercial motor vehicle drivers was found for most medical conditions. Little literature was available for crash risk among all drivers. For select conditions, such as seizure disorders, obstructive sleep apnea, and narcolepsy, there is evidence of increased crash risk among the general driving population and evidence-based guidance is now available. CONCLUSIONS:: Detailed guidance from the Medical Review Board is available for assessing commercial drivers with various disorders. Many challenges remain. Language: en
Structure-Activity Studies on Inhibition of Streptococcus mutans by Long-Chain Aliphatic Diamines

A series of long-chain aliphatic diamines, R1R2N(CH2)mNR 3-CnH2n+1, was tested for in vitro inhibition of Streptococcus mutans. In general, high activity was found for all analogs with alkyl chains containing 14 to 18 carbons. The nature of the substituents on the remainder of the alkylenediamine were of secondary importance. N-hydroxyethyl substituents tend to decrease activity. Good correlations of activity with quadratic functions of diamine critical micelle concentrations were obtained.
Buildup of the ring current during periodic loading‐unloading cycles in the magnetotail driven by steady southward interplanetary magnetic field

During prolonged intervals of negative interplanetary magnetic field (IMF) B z the magnetosphere often enters a state in which quasi-periodic, large-amplitude oscillations of energetic particle fluxes are observed at the geosynchronous orbit. We use the global magnetosphere MHD code BATS-R-US output during a long period of steady southward IMF B z to drive the Fok Ring Current Model. Previous simulations of such events demonstrated flat behavior of the energetic particle fluxes after the initial injection. Periodical north/south IMF turning was required to reproduce oscillations in particle fluxes at geosynchronous orbit. In the present study we use a global magnetosphere MHD code that reproduces fast magnetotail reconnection rates observed in kinetic simulations. This results in periodical loading-unloading cycles in the magnetotail even for steady southward B z and can explain quasi-periodic oscillations of geosynchronous energetic particle fluxes. The total proton energy within geosynchronous orbit exhibits overall growth in time due to quasi-steady convection and oscillates due to injection through inductive electric field caused by multiple dipolarization. The flux oscillation amplitude is stronger in- the outer regions of the ring current although the regions close to the geosynchronous orbit experience substantial perturbations as well.
Detecting Impurities in Liquids with Moire Patterns

Shifts in a moire pattern projected through a liquid are used to evaluate contamination levels too low to be recognized by refractometry.
Comparison and evaluation of analysis procedures for the quantification of (2-methoxyethoxy)acetic acid in urine.

Several extraction and derivatization procedures were evaluated for the quantification of (2-methoxyethoxy)acetic acid (MEAA) in urine. MEAA is a metabolite and a biomarker for exposure to 2-(2-methoxyethoxy)ethanol, a glycol ether with widespread use in various industrial applications and the specific use as an anti-icing additive in the military jet fuel formulation JP-8. Quantification of glycol ether biomarkers is an active area of analytical research. Various sample preparation procedures were evaluated: liquid–liquid extraction (LLE) using ethyl acetate yielded the highest recovery, and solid-phase extraction (SPE) gave low recovery of MEAA. Two derivatization procedures were thoroughly investigated and validated, namely, silylation of MEAA with N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA), and esterification of MEAA using ethanol. Quantification was performed by gas chromatography (GC) with a mass spectrometer as detector and using a polydimethylsiloxane (HP-1) capillary column. Deuterated 2-butoxyacetic acid (d-BAA) was used as an internal standard. Recovery studies of spiked human urine demonstrated the accuracy and precision of both procedures. The limit of detection (LOD) and other figures of merit for both derivatization procedures will be discussed in detail. Applications of these analysis procedures are also discussed.
Characterization of fracture toughness (G c ) of PVC and PES foams

The fracture behavior of polyvinyl chloride (PVC) and polyethersulfone (PES) foams has been examined using the single-edge notch bend and the double cantilever beam (DCB) tests. PVC foam densities ranging from 45 to 100 kg/m3 and PES foam densities ranging from 60 to 130 kg/m3 were examined. The PVC foams failed in a linear elastic brittle manner, whereas the PES foams displayed much more ductility and substantially larger toughness at a comparable foam density. The cell wall thickness of the PES foams was almost twice the thickness of the PVC foams which may have contributed to the high fracture toughness here defined as critical energy release rate (Gc). The PES foam, further displayed low initiation toughness, due to the sharp artificial crack tip and large toughness corresponding to propagation from a natural crack. The results show that the ductile PES foams have toughness close to its solid counterpart whereas the toughness of the PVC foams falls substantially below its solid counterpart.
Causes of an ad 774-775 14C increase.

Arising from F. Miyake, K. Nagaya, K. Masuda & T. Nakamura , 240–242 (2012)10.1038/nature11123 Atmospheric 14C production is a potential window into the energy of solar proton and other cosmic ray events. It was previously concluded that 14C results from ad 774–775 would require solar events that were orders of magnitude greater than known past events1. We find that the coronal mass ejection energy based on 14C production is much smaller than claimed in ref. 1, but still substantially larger than the maximum historical Carrington Event of 18592,3,4. Such an event would cause great damage to modern technology5,6, and in view of recent confirmation of superflares on solar-type stars7,8, this issue merits attention.
Chelatometric Determination of Ferrous Iron with 2-Pyridinealdoxime as an Indicator

Ferrous iron may be quantitatively determined by titration into a known EDTA solution containing 2-pyridinealdoxime as an indicator. The principal advantages of this method over oxidation-reduction procedures are that the reagents are more stable and reducing substances, in general, do not interfere.
When Min(A)−1 is Hausdorff

For a commutative ring with identity, say A, its collection of minimal prime ideals is denoted by Min(A). The hull-kernel topology on Min(A) is a well-studied structure. For example, it is known that the hull-kernel topology on Min(A) has a base of clopen subsets, and classifications of when Min(A) is compact abound. Recently, a program of studying the inverse topology on Min(A) has begun. This article adds to the growing literature. In particular, we characterize when Min(A)−1 is Hausdorff. In the final section, we consider rings of continuous functions and supply examples.
Extent and isotopic composition of Fe and Mo release from two Pennsylvania shales in the presence of organic ligands and bacteria

Abstract Isotopic fractionation of Fe and Mo during weathering could contribute toward the isotopic signatures of river and ocean waters. To investigate weathering processes, batch experiments were carried out at pH 6 under oxygenated conditions to investigate the influence of a nitrogen-fixing soil bacterium and organic ligands on the extent and isotopic signature of Fe and Mo release from two Pennsylvania shales with different mineralogies: an olive to grey shale (Rose Hill) and a black shale (Marcellus). Results of these studies showed that Fe and Mo were mainly released from illite, chlorite/vermiculite, and Fe oxides in the RHS and from pyrite in the MS. Dissolution rates of the clays estimated from our batch experiments are broadly consistent with published estimates. Release of Fe from both shales was only enhanced by the hydroxamate siderophore desferrioxamine B (DFAM). In contrast, none of the treatments enhanced release of Mo. Furthermore, release of this metal was measurable only for the black shale. For both shales, Fe that was released in the presence of DFAM was depleted in 56 Fe as compared to the bulk rock. In contrast, leachate solutions were enriched in the heavier Mo isotope as compared to the bulk Marcellus in all experiments with and without organic ligands and the bacterium. The isotopic fractionations in Fe and Mo are broadly consistent with previously reported fractionation effects during sorption onto precipitating Fe,Mn oxides. The observed Mo isotope fractionation is also consistent with all published studies of rivers, i.e., riverine Mo is enriched in heavy Mo isotopes. The observed Fe isotope fractionation is likewise consistent with published studies for some rivers, i.e., riverine Fe is sometimes depleted in 56 Fe. Our experimental results are consistent with sorption of Fe and Mo onto Fe (oxyhydr)oxides during weathering as a possible explanation for the isotopic signatures of these metals in many rivers.
Studies of an Adaptive Kaczmarz Method for Electrical Impedance Imaging

We present an adaptive Kaczmarz method for solving the inverse problem in electrical impedance tomography and determining the conductivity distribution inside an object from electrical measurements made on the surface. To best characterize an unknown conductivity distribution and avoid inverting the Jacobian-related term JTJ which could be expensive in terms of memory storage in large scale problems, we propose to solve the inverse problem by adaptively updating both the optimal current pattern with improved distinguishability and the conductivity estimate at each iteration. With a novel subset scheme, the memory-efficient reconstruction algorithm which appropriately combines the optimal current pattern generation and the Kaczmarz method can produce accurate and stable solutions adaptively compared to traditional Kaczmarz and Gauss-Newton type methods. Several reconstruction image metrics are used to quantitatively evaluate the performance of the simulation results.
Light-induced pH changes related to phosphorylation by chloroplasts

Abstract An unbuffered solution of isolated spinach chloroplasts manifests an increase in pH upon illumination which is reversed by turning the light off. The rate of the pH change and the amount of acid required to prevent this change (“yield”) are strongly stimulated by various co-factors which support photosynthetic phosphorylation in isolated chloroplasts. Pyocyanine has by far the largest effect, but FMN, vitamin K 5 , ferricyanide, and DCPIP also enhance this process. Conditions which inhibit electron flow inhibit the pH change. Various uncouplers of photophosphorylation, including NH 4 Cl, m -Cl-CCP, and the nonionic detergent Triton-X-100, also inhibit the reversible pH change. The relation of the pH shift to photosynthetic phosphorylation is discussed.
Breaking the Single-Molecule Limit in Biological Imaging

Chemically-selective imaging of biomolecules using labels is central to biological imaging. Although advances that allow resolving single fluorescently-labeled molecules with nanoscale resolution have been introduced, it is still a major challenge to extend the power of chemically-selective imaging to investigate single biomolecules with sub-molecular chemical and structural detail. To break this barrier, we have developed a chemo-mechanical labeling strategy employing single-stranded DNA to label target sites on a biomolecule and a nanomechanical readout mechanism based on atomic force microscopy to locate these labels. In analogy with fluorescence microscopy, the chemo-mechanical labeling strategy allows generating multi-color images wherein the sequence of DNA encodes color information. We demonstrate the basic utility of this approach by imaging the locations of biotins bound to a single streptavidin molecule.Figure 1. Chemically selective imaging within single biomolecules. a, Illustration of the imaging method employing single-stranded DNAs as chemo-mechanical labels and T-shaped cantilevers that allow locating the labels with sub-nanometer precision. b, Schematic of an application of this method to the imaging of biotin molecules bound to a single streptavidin. c, A 3-D topographical image of a single streptavidin, in which two black spots show the detected locations of biotins.View Large Image | View Hi-Res Image | Download PowerPoint Slide
Ineffective use of condoms among young women in managed care

Condoms must be used effectively in order to prevent pregnancy and the spread of HIV/STD. This study investigated two types of ineffective condom use, delayed condom use (initiated after penetration has occurred) and condom slippage and/or breakage. We estimated prevalence and identified predictors of ineffective condom use among young women at risk of STDs. The study used baseline survey data from a randomized trial of women 18-24 years old at two managed care sites; 779 participants who were recent condom users were included in this analysis. Forty-four per cent of the sample reported delayed condom use in the past three months and 19% reported condom slippage and/or breakage. In multivariate logistic regression, younger age, primary partner, lack of partner support, multiple recent sexual partners and using condoms for contraception were positively associated with delayed condom use. Correlates of condom slippage and/or breakage were non-white race/ethnicity and history of any STD. Greater frequency of condom use independently predicted both outcomes. Ineffective condom use was common in this sample of experienced condom users and predictors were different for each outcome. HIV/STD prevention interventions must address more specific aspects of condom use than have previously been their focus, especially when condom use is already high.
Biomechanical contributions of the trunk and upper extremity in discrete versus cyclic reaching in survivors of stroke.

AbstractBackground: Stroke rehabilitation interventions and assessments incorporate discrete and/or cyclic reaching tasks, yet no biomechanical comparison exists between these 2 movements in survivors of stroke. Objective: To characterize the differences between discrete (movements bounded by stationary periods) and cyclic (continuous repetitive movements) reaching in survivors of stroke. Methods: Seventeen survivors of stroke underwent kinematic motion analysis of discrete and cyclic reaching movements. Outcomes collected for each side included shoulder, elbow, and trunk range of motion (ROM); peak velocity; movement time; and spatial variability at target contact. Results: Participants used significantly less shoulder and elbow ROM and significantly more trunk flexion ROM when reaching with the stroke-affected side compared with the less-affected side (P < .001). Participants used significantly more trunk rotation during cyclic reaching than discrete reaching with the stroke-affected side (P = .01). No ...
Laser-induced, in situ, nanoparticle shell synthesis in polymer matrix nanocomposites

This work investigates processes involved in the patterning and production of structured nanoparticles in polymer matrix nanocomposites using femtosecond laser irradiation. An in situ, chemical vapor deposition process was used to synthesize silver nanoparticles in the bulk of an optically transparent polytetrafluoroethylene-co-hexafluoropropylene polymer matrix. The strong optical absorption at the surface plasmon resonance frequency was used to selectively irradiate and photothermally heat the material near particles using femtosecond laser pulses. Having species for chemical vapor deposition in the near-particle environment allows for localized decomposition of the precursor species via unimolecular reactions. Decomposition products can subsequently participate in the production of a variety of core-shell nanostructures. The overall process is demonstrated using femtosecond, photothermal heating of silver nanoparticles to decompose tungsten hexacarbonyl in the polymer matrix leading to the formation of tungsten oxide shells surrounding the silver. For this system, a 40 nm red shift of the surface plasmon resonance was measured. Control of the spatial and temporal characteristics of the excitation source allows for synthesis of nanocomposites with a high degree of control over the location, composition and size of nanoparticles in a polymer matrix resulting in patterned materials with continuously variable properties.
Nonsingularity Conditions for Multifunctions

We discuss three different characterizations of continuity properties for general multifunctions S : Rd ⇒ Rn. Each of these characterizations is given by the same simple nonsingularity condition, but stated in terms of three different generalized derivatives. Two of these characterizations are known, but the third is new to this paper. We discuss how all three have immediate analogues as generalized inverse mapping theorems, and we apply our new characterization to develop a fundamental and very broad sensitivity theorem for solutions to parameterized optimization problems.
No-Enema Therapy for Idiopathic Constipation and Encopresis

Idiopathic constipation and encopresis of childhood are thought to occur when children volitionally withhold stool. Withholding may be prompted by social pressures or by episodes of painful defecation. Repetitive withholding may result in colonic dilatation and colorectal dysfunction. Therapy involves removal of impacted stool, stool softening, and behavioral therapy. The use of enemas in this therapy is widespread but may be counterproductive. A retrospective review of patients treated without enemas revealed 45 patients whose course could be followed for six months. Ninety-eight percent of these had successful initial cleanouts without enemas; 94% had continued success at six months. These results, comparable with other treatment programs, demonstrate that therapy without enemas is a reasonable alternative in the treatment of childhood constipation and encopresis.
Analysis of ovarian borderline tumors using comparative genomic hybridization and fluorescence in situ hybridization.

It is unclear whether ovarian borderline tumors (tumors of low malignant potential) are independent entities or whether they are part of a continuum of tumor progression that culminates in ovarian carcinoma. Little is known about genetic abnormalities in borderline tumors because of the difficulty of growing them in culture for chromosome studies, and because the low ratio of tumor to nontumor cells can interfere with molecular genetic examination. To circumvent these problems, we performed comparative genomic hybridization (CGH) on 10 serous borderline tumors from nine patients, using microdissection to enrich the samples for tumor DNA and reduce contamination from stromal and inflammatory cells. CGH analysis revealed that three of the tumors had detectable chromosomal imbalances, whereas seven were in a balanced state. In those tumors with imbalances, the number of abnormalities ranged from 3-6 per tumor. Additional studies by fluorescence in situ hybridization (FISH) on disaggregated nuclei confirmed the imbalances detected by CGH, revealed one tumor to be hypertriploid, and indicated that the remaining tumors were diploid and in a balanced state. All abnormalities observed in the aneuploid cases are consistent with chromosomal aberrations previously reported for ovarian carinomas, providing further evidence that some borderline tumors are part of a continuum of tumor progression. These results also suggest that there may be different mechanisms leading to borderline tumor formation, including one associated with multiple chromosomal imbalances, and others that do not involve imbalances detectable by CGH. Genes Chromosomes Cancer 25:307-315, 1999.
Role of movement stability in reducing slip-related balance loss and falls among older adults

Falling is a major cause of injury and death among older adults. Improving stability of the body center of mass (COM) state (i.e., its velocity and position) may reduce fall incidence. We used a combination of experimental and mathematical models to verify the hypothesis that an improvement in mathematically predicted dynamic stability at perturbation onset correlated with a subsequent reduction in balance loss. Slips were induced during a sit-to-stand task in 41 older adults, who were exposed to a block of slip trials followed by a block of nonslip trials and a reslip trial. COM stability was quantified as the shortest distance between its state measured at seat-off (slip onset) and the mathematically predicted feasible stability region boundary. With repeated exposure to slips, older adults exponentially reduced their incidence of falls and backward balance loss, which significantly related to an increase in predicted stability. With exposure to slip and nonslip conditions, subjects began to select "optimal" movements that allowed a balance loss to be avoided under both conditions. These results can be fully accounted for when we assume that an internal model representing the COM stability limits guides the feedforward control during adaptation to a risk of slipping.
Youth Gang Membership and Serious Violent Victimization: The Importance of Lifestyles and Routine Activities

Youth gangs have received substantial scholarly and public attention during the past two decades. Although most of the extant research on youth gang members has focused on their offending behaviors, recent studies have examined the victimization of youth gang members relative to their nongang peers. Gang members generally have been found to be at increased risk of victimization, although the reasons for this relationship have not fully been explored. The current study uses data from a multisite study of youth to explore whether the gang membership-victimization link is mediated by lifestyles and routine activities. In other words, is gang members' involvement in delinquent lifestyles and routine activities a viable explanation for their increased risk of serious violent victimization? Implications of these findings and suggestions for future research and policy are discussed.
Social relations, language and cognition in the 'oldest old'

This paper reports a study of the associations between social relations, language and cognition among people aged 85 or more years (hereafter the ‘ oldest old ’). Although the links between cognition and both social relations and language ability are well-established, less is known about the relationship between social relations and language skills, especially among the oldest old. With a sample of 20 adults aged 85–93 years living independently in two retirement communities (a seniors’ apartment complex and independent apartments in a continuum-of-care setting), we used the approach of the Rochester Interaction Record to assess the frequency, purpose and quality of their social interactions over one week. It was hypothesised that aspects of social relations, as well as the type of residential setting, would associate with both cognitive skills (measured using the Composite Cognistat) and language skills (measured using the Boston Naming Test). It was found that participants who had a low proportion of interactions with family members, or a high proportion with friends, as well as those with diverse relationships, performed better on the cognitive and language tasks. Furthermore, those from the setting with more programmed activities performed better on the language task. The conclusion critically examines the findings about the influence of family relationships and the importance of residential setting.
On the MDL principle for i.i.d. sources with large alphabets

Average case universal compression of independent and identically distributed (i.i.d.) sources is investigated, where the source alphabet is large, and may be sublinear in size or even larger than the compressed data sequence length n. In particular, the well-known results, including Rissanen's strongest sense lower bound, for fixed-size alphabets are extended to the case where the alphabet size k is allowed to grow with n. It is shown that as long as k=o(n), instead of the coding cost in the fixed-size alphabet case of 0.5logn extra code bits for each one of the k-1 unknown probability parameters, the cost is now 0.5log(n/k) code bits for each unknown parameter. This result is shown to be the lower bound in the minimax and maximin senses, as well as for almost every source in the class. Achievability of this bound is demonstrated with two-part codes based on quantization of the maximum-likelihood (ML) probability parameters, as well as by using the well-known Krichevsky-Trofimov (KT) low-complexity sequential probability estimates. For very large alphabets, kGtn, it is shown that an average minimax and maximin bound on the redundancy is essentially (to first order) log(k/n) bits per symbol. This bound is shown to be achievable both with two-part codes and with a sequential modification of the KT estimates. For k=Theta(n), the redundancy is Theta(1) bits per symbol. Finally, sequential codes are designed for coding sequences in which only m<min{k,n} alphabet symbols occur
Characterization of Defects in Silicon Ribbons By Combined Ebic and Hvem

The electrical properties and crystallographic nature of linear and planar defects in EFG silicon ribbons were studied. A direct correlation between electrical and structural properties was obtained by imaging the same areas first with EBIC and then with HVEM. Coherent twin boundaries were found to be electrically inactive, but higher order twins and other grain boundaries generally enhanced minority carrier recombination. Partial dislocations confined to coherent twin boundaries were usually electrically active, but in certain instances partial dislocations were observed which had no apparent EBIC contrast.
Comment on “Method for Real-Time Frequency Response and Uncertainty Estimation”

TECHNICAL COMMENTS are brief discussions of papers previously published in this journal. They should not exceed 1500 words (where a figure or table counts as 200 words). The author of the previous paper is invited to submit a reply for publication in the same issue as the Technical Comment. These discussions are published as quickly as possible after receipt of the manuscripts. Neither AIAA nor its Editors are responsible for the opinions expressed by the authors.
Creation of a driver preference objective metric to evaluate ground vehicle steering systems

The evaluation of vehicle steering systems has typically been performed by engineers and consumer focus groups using in-vehicle and automotive simulator studies. In the latter case, driver preferences have been extensively gathered using written questionnaires. However, this delays the testing procedure and may introduce outside influences that may skew the results. In this paper, an objective steering preference metric has been created to gather steering preferences without directly communicating with the driver. Streaming vehicle data has been recorded, processed, and correlated with subjective response data to create a global steering preference metric. A combination of the vehicle's yaw rate, longitudinal acceleration, and lateral acceleration demonstrated an excellent correlation with survey responses regardless of the steering setting. Furthermore, changes in the steering ratio resulted in an even stronger correlation between the objective data (longitudinal acceleration, front tire angle, and throttle position) and test subject questionnaire responses. Overall, the proposed index offers a unique approach to evaluate steering system designs.