cssi/SciSciGPT-SciSciNet huggingface dataset:
Plasticity in AAA+ proteases reveals ATP-dependent substrate specificity principles

In bacteria, AAA+ proteases such as Lon and ClpXP specifically degrade substrates to promote growth and stress responses. Here, we find that an ATP-binding mutant of ClpX suppresses physiological defects of a Lon-deficient strain by shifting ClpXP protease specificity toward normally Lon-restricted substrates and away from normal ClpXP targets. Reconstitution with purified proteins assigns these effects to changes in direct recognition and processing of substrates. We show that wildtype ClpXP specificity can be similarly altered when ATP hydrolysis is reduced, which unexpectedly accelerates degradation of some substrates. This activation corresponds with changes in ClpX conformation, leading to a model where ClpX cycles between capture and processive states depending on ATP loading. Limiting ATP binding alters dynamics between states affording better recognition of unorthodox substrates, but worse degradation of proteins specifically bound by the processive state. Thus, AAA+ protease specificities can be directly tuned by differences in ATP hydrolysis rates. HighlightsO_LIA mutation in the Walker B region of ClpX induces recognition of new substrates. C_LIO_LIProteases are optimized for specific functions but barrier to recognize new substrates is easily overcome. C_LIO_LIExpanding substrate recognition by a protease comes at the cost of reducing native substrate degradation. C_LIO_LIDecreasing ATP enhances ClpXP mediated degradation of certain classes of substrates. C_LIO_LIClpX adopts distinct conformational states to favor better recognition of some substrates over others. C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=183 HEIGHT=200 SRC="FIGDIR/small/456811v1_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@fe7c1corg.highwire.dtl.DTLVardef@1862957org.highwire.dtl.DTLVardef@1044c0forg.highwire.dtl.DTLVardef@11d7168_HPS_FORMAT_FIGEXP M_FIG C_FIG In a wildtype cell, AAA+ proteases Lon and ClpXP promote normal growth by degrading distinct substrates. ClpX*P can compensate for the absence of the Lon protease by tuning ClpXP substrate specificity to better degrade Lon-privileged substrates (such as DnaA, SciP, and misfolded proteins) but this comes at the cost of native ClpXP substrates (such as ssrA-tagged proteins and CtrA). We propose that ClpX alternates between a closed and open conformation and promoting one state over the other leads to alterations in substrate specificity. In the presence of ClpX* or in ATP-limited conditions, the open state is favored, allowing capture and recognition of substrates such as casein. The balance shifts to the closed state under high ATP conditions, allowing degradation of substrates such as GFP-ssrA, which preferentially bind the closed state.
Stratified-Charge Fuel Preparation Influence on the Misfire Rate of a DISI Engine

The influence of mixture preparation on misfires at idle in a Direct Injection Spark Ignition (DISI) engine was investigated. A wall-guided DISI engine was run at idle conditions in a stratified charge mode (750 rpm / 90 kPa MAP). Images of the mixture composition at the spark plug were taken at spark timing using Planar Laser Induced Fluorescence (PLIF.) for several different End-of-injection (EOI) timings and spark timings. Cylinder pressure data were acquired simultaneously with the images to identify misfire cycles. he misfire rate was found to increase as the EOI timing was advanced from the optimal timing, defined by maximum stability and lowest ISFC. Images show that the misfire rate at a particular operating condition can be correlated to the fuel distribution and the location of the stratified charge in the engine. Cycles that showed a lower amount of stratification (overmixing) and/or high gradients in fuel concentration near the spark plug were the least stable. At the most advanced EOI timings, the charge was shown to have overpenetrated and moved past the spark plug in its trajectory, increasing the misfire rate. Retarding the spark timing yielded the same result as advancing the EOI. Advancing the spark timing resulted in a charge that appeared to still be in the process of exiting the bowl during the spark event and increased the misfire rate. Individual misfire cycles were also compared to average firing cycles. These cycles displayed both a large amount of variation from the mean and very poor charge formation, in terms of location and fuel concentration.
HIGHWAY SAFETY APPURTENANCES: STATE-OF-THE-ART

To reduce the horrendous toll on our nation's roadways, (50,000 fatalities per year) highway agencies, researchers, and industries are responding effectively to safety legislation by Congress. Among the many safety initiatives taken was the systematic installation of forgiving appurtenances developed to reduce the 17,000 - 22,000 deaths involved in errant vehicle collisions. Statistical data, for errant vehicle roadway departures and for accident-frequency collisions with the existing roadside obstacles, define the enormity of the problem confronted. Traffic railings and impact attenuators are designed as containment or redirective protective safety appurtenances, or both as the situation requires. Devices are explored that could be installed along our highways and used as temporary systems to protect motorists and workmen during construction and maintenance operations. Language: en
Ty1 insertions in intergenic regions of the genome of Saccharomyces cerevisiae transcribed by RNA polymerase III have no detectable selective effect

The retrotransposon Ty1 of Saccharomyces cerevisiae inserts preferentially into intergenic regions in the vicinity of RNA polymerase III-transcribed genes. It has been suggested that this preference has evolved to minimize the deleterious effects of element transposition on the host genome, and thus to favor their evolutionary survival. This presupposes that such insertions have no selective effect. However, there has been no direct test of this hypothesis. Here we construct a series of strains containing single Ty1 insertions in the vicinity of tRNA genes, or in the rDNA cluster on chromosome XII, which are otherwise isogenic to strain 337, containing zero Ty1 elements. Competition experiments between 337 and the strains containing single Ty1 insertions revealed that in all cases, the Ty1 insertions have no selective effect in rich medium. These results are thus consistent with the hypothesis that the insertion site preference of Ty1 elements has evolved to minimize the deleterious effects of transposition on the host genome.
Integrative Population Analysis for Better Solutions to Large-Scale Mathematical Programs

Integrative Population Analysis unties the learning process called target analysis and a generalized form of sensitivity analysis to yield improved approaches for optimization, particularly where problems from a particular domain must be solved repeatedly. The resulting framework introduces an adaptive design for mapping problems to groups, as a basis for identifying processes that permit problems within a given group to be solved more effectively. We focus in this paper on processes embodied in parameter-based definitions of regionality,accompanied by decision rules that extract representative solutions from given regions in order to yield effective advanced starting points for our solution methods. Applied to several industrial areas, our approach generates regions and representations that give an order of magnitude improvement in the time required to solve new problems that enter the population and therefore makes the application of large scale optimization models practical in reality.
A case study of induced trips at mixed-use developments

Conventional thinking suggests that pedestrian-friendly, mixed-land-use developments will contribute to an overall reduction in travel by providing an alternative to automobile travel. However, these elements may serve to increase travel demand by reducing the overall cost of travel—a phenomenon generally known as 'induced' travel. To date, most studies of induced travel have focused on aggregate travel patterns, without examining how development patterns may influence people's trip-making decisions. To fill a void in the empirical research, we examine the potential for induced trip making at mixed-use developments by analyzing data obtained from a survey of travelers at a typical mixed- use site in suburban Dallas, Texas, USA. Our analysis found that during both the morning and afternoon study periods, at least some percentage of internal trips at the case-study site were induced, and not 'captured' from the external street network as is typically assumed. Induced trips by land-use pair and travel mode are also reported. Even with the induced trips, a reduction in regional vehicle-miles traveled can still be realized at mixed-use developments sites due to the propensity for those trips to be made on foot. Induced travel also has implications for the development of traffic-impact studies for proposed mixed-use sites, which generally assume that all internal trips are replacing external trips. Planners, policy makers, politicians, and other stakeholders exploring mixed-use developments are encouraged to consider the implications of induced travel in the mixed-use environment as a land-use solution to urban traffic congestion and air-quality issues.
Child Protection Investigations in Out-of-Home Care Perpetrators, Victims, and Contexts

Keeping children safe in out-of-home care requires an understanding of the contexts under which maltreatment occurs. This study examines how maltreatment investigations differ across four settings (nonrelative foster, informal kinship, formal kinship, and congregate care). I focus on four elements of maltreatment: the perpetrator's role (e.g., out-of-home caregiver and peer), maltreatment type, probability of substantiation, and victim characteristics. I use statewide Wisconsin administrative data in years 2005-2012, which has an analytic sample of over 96,000 placements. Data are analyzed using descriptive statistics and multi-level logistic regression. Alleged maltreatment is not uncommon in out-of-home care-the total investigation rate ranged from 5% (congregate care) to 15% (informal kinship care). Four percent of all placements were investigated for maltreatment by an out-of-home caregiver, of which 9% were substantiated. Maltreatment by peers (siblings or other foster children) was investigated in 1% of all placements, of which 20% were substantiated. Neglect was the most commonly alleged maltreatment type in informal kinship care, whereas physical abuse was most commonly alleged in all other placement types. Children who were female, Black, or between ages 6 and 10 experienced heightened risk of maltreatment in out-of-home care.
Building multi-way gateways for local area networks

A method is proposed for constructing multiway gateways to interconnect several local area networks (LANs) or wide area networks (WANs) and provide gateway services among them. A multiway gateway accommodates intercommunications between networks whose subnet protocols may differ and whose locations may be geographically dispersed, and has advantages of flexibility and efficiency. The proposed approach uses the concept of remote gateways, in which the functionality of a gateway is partitioned into two separate modules (local and remote), and a dedicated communication link connects these two parts. A description is given of the concept of a remote gateway and the approach used to construct multiway gateways based on them. The design issues for a multiway gateway and possible applications to network management are also addressed. >
Total cross section of neutrons on deuterium in the keV region

Total neutron cross sections on deuterium in the energy range 1 keV to 1000 keV were measured, and basically agree with our previously reported results. (auth)
The Complexity Of Pebbling Reachability And Solvability In Planar And Outerplanar Graphs

Given a simple, connected graph, a pebbling configuration is a function from its vertex set to the nonnegative integers. A pebbling move between adjacent vertices removes two pebbles from one vertex and adds one pebble to the other. A vertex r is said to be reachable from a configuration if there exists a sequence of pebbling moves that places at least one pebble on r. A configuration is solvable if every vertex is reachable. We prove that determining reachability of a vertex and solvability of a configuration are NP-complete on planar graphs. We also prove that both reachability and solvability can be determined in O(n6) time on planar graphs with diameter two. Finally, for outerplanar graphs, we present a linear algorithm for determining reachability and a quadratic algorithm for determining solvability. To prove this result, we provide linear algorithms to determine all possible maximal configurations of pebbles that can be placed on the endpoints of a path and on two adjacent vertices in a cycle.
Generalized parton distributions for large x

Abstract The t -dependence of generalized parton distributions for x →1 is discussed. Based on a Fock space expansion, we argue that models, where the t -dependence for x →1 is through the product (1− x ) t , are inconsistent. Instead we suggest a leading dependence in terms of (1− x ) n t , where n ⩾2, for x →1.
TSV electrical and mechanical modeling for thermo-mechanical delamination

This paper presents the electrical modeling of thermo-mechanical delamination in TSVs, such as circumferential and interfacial cracks. Two-dimensional mechanical finite element models were built to analyze the stress distribution in TSV structures. Abaqus simulations were performed to compute the energy release rate at the crack when stress is applied and to track the propagation of cracks over different thermal cycles. The mechanical models were then translated to electrical defect models, to evaluate the electrical performance of TSVs with delaminations.
Occurrence of Bythotrephes cederstroemi (Schoedler 1877) in Lake Superior, with Evidence of Demographic Variation within the Great Lakes

Abstract The predaceous cladoceran, Bythotrephes cederstroemi (Schoedler 1877), was first noted in the Great Lakes in late 1984, and had spread to Lakes Huron, Erie, Ontario, and Michigan by late summer of 1986. Zooplankton samples collected from Batchawana Bay, Lake Superior on 15 September 1988 contained large numbers of B. cederstroemi (122.8 individuals/m 2 ). Geographic variation in Great Lakes B. cederstroemi was observed when this sample was compared to samples from Lake Erie. There was a greater percentage of males present in the Lake Superior sample as well as a greater number of females carrying sexual resting eggs. B. cederstroemi from Lake Superior weighed more than those from Lake Erie. These differences are probably the result of physiological responses to different environmental conditions, and not genetic differentiation of B. cederstroemi populations among the Great Lakes.
Gular and paracloacal gland secretions of crocodilians: A comparative analysis by thin-layer chromatography

Abstract The gular and the paracloacal gland secretions of 21 crocodilian species, including representatives of all extant genera—Alligator, Caiman, Crocodylus, Gavialis, Melanosuchus, Osteolaemus, Paleosuchus, and Tomistoma—were analysed by thin-layer chromatography. Secretions from one adult male and one adult female were examined separately for most species. Gular and paracloacal gland chromatograms display bands consistent with sterols, free fatty acids, triglycerides, steryl esters, and other compound classes. Comparisons of gular and paracloacal chromatograms of each species suggest qualitative and/or quantitative differences in the compounds produced in each gland type. Our results provide tentative evidence for taxonomic variation in crocodilian skin gland secretions. Comparisons of gular and paracloacal gland chemicals of extant species allow inferences to be made on the chemicals produced by these organs in ancestral crocodilians.
Race Relations and Politics in Colonial Zambia: The Elwell Incident

It is no use blinking our eyes to the fact that a strong and efficient colour bar exists at present and to the probability that the Europeans will do their best to preserve it. [Africans] are becoming increasingly conscious of it and everything is set for a struggle between the races, which is certain to come eventually, unless an unexpected change in the European attitude takes place or the managements are in a position to resist pressure from the European union.
Statistical profile generation for traffic monitoring using real-time UAV based video data

The eye-in-the-sky alternative to collecting real-time temporal/spatial data using small unmanned helicopters is proposed to: monitor traffic, evaluate and assess traffic patterns and provide accurate vehicle counts. Collected real-time visual data are converted to traffic statistical profiles and used as continuously updated inputs to existing traffic simulation models improving calibration, accuracy (in terms of variable parameter values) and future traffic predictions. Functionality of simulation models is enhanced, and reliability is improved The proposed approach offers significant advantages over conventional methods where historical and outdated data is used to run poorly calibrated traffic simulation models.
An intraoral surveyor

A device is described for checking tooth preparations of abutment teeth for fixed or removable partial dentures. The device quickly and accurately indicates the planned path of insertion of the prosthesis intraorally, serves as a visual guide during the preparation of teeth, and aids the dentist in evaluating tooth preparations before making a final impression. This intraoral surveyor provides an inexpensive, practical, and readily available method for producing optimal tooth preparations for fixed and removable partial dentures.
A multiple option observation system for experimental studies: MOOSES

The purpose of this article is to outline the development of the Multiple Option Observation System for Experimental Studies (MOOSES), a flexible data collection package for applied behavioral research. Several data collection options are available to users of MOOSES. Event-based recording, interaction-based recording, duration recording, and interval recording are available to the users and can be used individually or together, depending upon the research question. The collection program can incorporate any of the keys on the keyboard. Function keys on the top or side are used for toggle (duration states) type data collection. Types of analysis include frequency and duration of discrete events, frequency of general behavior states, frequency and duration of events within behavioral states, percent interval analysis, sequential analysis, and interobserver agreement. Data obtained from MOOSES is easily incorporated with other data for further statistical analysis with standard statistical packages or popular spreadsheet programs. Applications of MOOSES and its uses in social interaction research are presented. Comparisons with other similar systems are provided.
Bankruptcy risk, firm-specific managerial human capital, and diversification

This paper proposes a model in which firm diversification acts as an efficient form of nonpecuniary compensation for the manager. In the model diversification rewards the manager by reducing the likelihood of bankruptcy which in turn increases the expected value of his firm-specific human capital. Unlike the principal-agent model of diversification, this model shows that diversification may be optimal even if the manager is risk neutral and his behavior can be observed by firm owners.
Temperature- and fiber-Bragg-grating-controlled continuously tunable diode laser

Continuously tunable diode laser sources coupled to single-mode fiber are useful sources for fiber Bragg grating (FBG) strain sensors. A low-cost 1300 nm laser diode is anti-reflection coated making it nearly an LED. By coupling this coated laser to a short length of single-mode fiber containing a low-reflection FBG, which serves as the new tunable laser output coupler, a tunable, fiber-coupled laser source is possible. The laser diode package is mounted in a temperature-controlled mount, and the FBG is mounted so it can be strained. By controlling both temperature and FBG strain, the laser can be continuously tuned across a 10 nm spectral range giving a narrow line laser source for use in strain sensors.
The central limit theorem under censoring

The central limit theorem for integrals of the Kaplan-Meier estimator is obtained. The basic tools are the martingale methods developed by Gill and the identities and inequalities of Efron and Johnstone. The assumptions needed are both weaker and more transparent than those in the recent literature, and the resulting variance expression is simpler, especially for distributions with atoms.
Investigating sorption-driven dissolved organic matter fractionation by multidimensional fluorescence spectroscopy and PARAFAC.

Soil organic matter is involved in many ecosystem processes, such as nutrient supply, metal solubilization, and carbon sequestration. This study examined the ability of multidimensional fluorescence spectroscopy and parallel factor analysis (PARAFAC) to provide detailed chemical information on the preferential sorption of higher-molecular-weight components of natural organic matter onto mineral surfaces. Dissolved organic matter (DOM) from soil organic horizons and tree leaf tissues was obtained using water extracts. The suite of fluorescence spectra was modeled with PARAFAC and it was revealed that the DOM extracts contained five fluorescing components: tryptophan-like (peak location at excitation tryptophan-like components (52% sorption) > tyrosine-like components (29% sorption). This differential sorption of the modeled DOM components in both the soil organic horizon and leaf tissue extracts led to the fractionation of DOM. The results of this study demonstrate that multidimensional fluorescence spectroscopy combined with PARAFAC can quantitatively describe the chemical fractionation process due to the interaction of DOM with mineral surfaces.
THE IDENTITY OF INDISCERNIBLES AND THE CO‐LOCATION PROBLEM

: The Identity of Indiscernibles is the principle that there cannot be two individual things in nature that are qualitatively identical. The principle is not exactly popular. Michael Della Rocca tries to resurrect it by arguing that we must accept this principle, for otherwise we cannot explain the impossibility of completely overlapping indiscernible objects of the same kind that share all their parts and exist in the same place at the same time. I try to show that his argument goes wrong: we need not embrace the identity of indiscernibles to deal with the co-location problem.
Probabilistic approaches to estimating variation in the mechanical properties of rock masses

Abstract The probabilistic method of estimating mechanical characteristics of a rock mass is discussed, based on Monte Carlo simulation. The simulation results and the input data used for the simulation are analyzed using extreme value statistics. The analysis indicates that the mechanical properties obtained from simulation, laboratory and field tests, follow the third type asymptotic distribution of the smallest values. This analysis reveals the nature of the inherent variability of the mechanical properties of rocks. The proposed approach provides a viable means of assessing the variability of the rock mass properties which cannot be accomplished by experimental means. These computed rock mass characteristics will help rock engineers to arrive at a more rational design of underground structures, compared to traditional design methods based on deterministic approaches.
Fourier Transform Infrared Spectroscopic Assessment of Changes in Composition of Proteoglycans and Collagen in Developing Human Fetal Tarsal Bones

The proteoglycan and collagen composition of cartilage is known to change during fetal and postnatal development. The current report represents the first attempt to semi-quantitatively determine the changes in the composition of developing human fetal cartilage. Human fetal talus bones were obtained from late 2nd and 3rd trimester specimen. Fetal bones are comprised of an intramembranous tissue commonly referred to as cartilage anlagen. During maturation the anlagen develops an ossific nucleus. Fourier Transform Infrared Spectroscopy (FT-IRS) and Fourier Transform Infrared Imaging Spectroscopy (FT-IRIS) were used to assess the changes in composition relating to tissues main constituents, collagen (COL) and proteoglycan (PG). FT-IRS was used to obtain average values of composition across the entire anterior-posterior length of each bone. Relative percent composition values of COL and PG were calculated by multivariate least-squares analysis of model compound spectral features associated with COL (Amide I spectral absorbance) and PG (C-O-C sugar absorbance). It was shown that PG/Amide I values decreases from 4.9 +/−3.4 to 2.9 +/−3.2 over development. These values were translated to a relative percent compositional drop of PG from 49.9% +/−16.2% to 36.4% +/−8.1%. FT-IRIS was used to observe the spatial changes in composition from the subchondral region to the articulating surfaces. Collagen was observed to be distributed away from the articulating surfaces with increase in development. Proteoglycans were observed to have uniform concentrations with a marked decrease in PG across developmental stages. A noticeable benchmark in development is the ossific nucleus which was absent in the 2nd trimester. The findings of the current study demonstrate that cartilage anlage contains approximately triple the amount of proteoglycan in the 2nd trimester as compared to that previously reported in hyaline articular cartilage. The proteoglycan decreases over development, resulting in double the proteoglycan in the 3rd trimester as compared to previously reported adult values. No site-specific, macroscopic (FT-IRS), differences in PG content were found while microscopic assessment (FT-IRIS) observed heterogeneity with marked changes in PG content.Copyright © 2008 by ASME
Signal processing system to quantify bilirubin in the jaundice clinical model spectra

Neonatal jaundice is a medical condition which occurs in newborns as a result of an imbalance between the production and elimination of bilirubin. Excess bilirubin in the blood stream diffuses into the surrounding tissue leading to a yellowing of the skin. An optical system integrated with a signal processing system is used as a platform to noninvasively quantify bilirubin concentration through the measurement of diffuse skin reflectance. Initial studies, based on simulated skin reflectance spectra have lead to the generation of a clinical model for neonatal jaundice which, generates spectral reflectance data for jaundiced skin with varying levels of bilirubin concentration in the tissue. The spectral database built using the jaundice clinical model is then used as a test database to validate the signal processing system in real time. This evaluation forms the basis for understanding the translation of this research to human trials. The new jaundice clinical model and signal processing system have been successful validated using a porcine model as a surrogate for neonatal skin tissue. Samples of pig skin were soaked in bilirubin solutions of varying concentrations to simulate jaundice skin conditions. The resulting skins samples were analyzed with our skin reflectance systems producing bilirubin concentration values that show a high correlation (R2 = 0.96) to concentration of the bilirubin solution that each porcine tissue sample was soaked in‥
Furans in Synthesis. The Preparation of Spiro-Cyclic Systems.☆

Abstract Furan-terminated cationic cyclizations allylic alcohols, enones, and N-acyl iminium ions as initiators have been explored as routes to highly functionalized spiro[4,5]decanes, spiro[5,5]undecanes, spiro[4,6]undecanes, and spiro[5,6]dodecanes.
THE DESTRUCTION OF INSULIN BY INTACT MICE1

IT HAS been demonstrated that insulin is destroyed “in vitro” by slices, homogenates and extracts of liver (Mirsky and Broh-Kahn, 1949; Mirsky and Perisutti, 1953; Mirsky, Perisutti and Dixon, 1954; Mirsky, Perisutti and Dixon, 1955; Tomizawa, Nutley, Marahara and Williams, 1954). Although it is generally agreed that insulin is destroyed also by the intact animal (Greely, 1940; Mirsky, Podore, Wachman and Broh-Kahn, 1948; Haugaard, Vaughan, Haugaard and Stadie, 1954), the evidence of such destruction is quite indirect. In order to obtain more definitive evidence of insulin destruction “in vivo,” the rate of degradation of I131 labeled insulin by the intact mouse was determined. method Fed male mice of from 18 to 25 gm. in weight were given an intraperitoneal injection of two units insulin per 100 gm. of body weight and a subcutaneous injection of 1 ml. of a 5.5% glucose solution. The total volume of insulin injected intraperitoneally was 0.02 ml. per gram body weight.
SERUM PROSTATE SPECIFIC ANTIGEN IS A STRONG PREDICTOR OF FUTURE PROSTATE GROWTH IN MEN WITH BENIGN PROSTATIC HYPERPLASIA

Purpose: We analyze patterns of prostate growth in men diagnosed with benign prostatic hyperplasia (BPH) and treated with placebo during 4 years, and determine which baseline parameters were the st...
A fiber-optic cyclodextrin-based sensor.

Abstract This paper describes the development of a fiber-optic cyclodextrin-based (FCD) sensor. The device uses laser excitation and fluorescence detection with β-cyclodextrin as the reagent phase, immobilized at the tip of an optical fiber. The sensitivity of the FCD sensor is 14 times as great as that of a bare optical fiber when measurements are made with the fiber immersed in a buffer after a 10-min incubation period. The selectivity of the sensor is illustrated with pyrene as the model compound and 5,6-benzoquinoline as the interferent. An interference study with a contaminated environmental ground water sample is used to illustrate the usefulness of the FCD device.
Inflammation, reproduction, cancer and all that…. The regulation and role of the inducible prostaglandin synthase

Discovery of a second, inducible prostaglandin synthase provides explanations for many previously puzzling observations, but also raises new questions about prostanoid synthesis. A cis-acting sequence closely related to the cyclic AMP response element has been shown to play a role in both basal and induced prostaglandin synthase 2 gene expression. Aspirin and other currently available non-steroidal anti-inflammatory drugs that inhibit prostaglandin synthase activity do not effectively discriminate between the inducible prostaglandin synthase 2 and constitutive prostaglandin synthase 1 enzymes. Identification of a second prostaglandin synthase, induced by inflammatory stimuli, initiated a search for isoform-specific inhibitors. Use of prostaglandin synthase 2 specific inhibitors and antisense oligonucleotides has led to the suggestion that specific ligands activate alternative pathways of prostanoid production, using one of the prostaglandin synthase isoforms preferentially. The coupling mechanisms by which these pathways are activated in response to alternative stimuli should provide additional routes of intervention in prostanoid production.
Thermal transport and grain boundary conductance in ultrananocrystalline diamond thin films

Although diamond has the highest known room temperature thermal conductivity, k∼2200W∕mK, highly sp3 amorphous carbon films have k<15W∕mK. We carry out an integrated experimental and simulation study of thermal transport in ultrananocrystalline diamond (UNCD) films. The experiments show that UNCD films with a grain size of 3–5nm have thermal conductivities as high as k=12W∕mK at room temperature, comparable with that of the most conductive amorphous diamond films. This value corresponds to a grain boundary (Kapitza) conductance greater than 3000MW∕m2K, which is ten times larger than that previously seen in any material. Our simulations of both UNCD and individual diamond grain boundaries yield values for the grain boundary conductance consistent with the experimentally obtained value, leading us to conclude that thermal transport in UNCD is controlled by the intrinsic properties of the grain boundaries.
Regulation of G protein signalling in yeast

A common property of cell signaling systems is the ability to adapt to chronic stimulation. A genetic analysis of receptor/G protein signaling in yeast has led to the identification of a new class of regulators of G protein signaling (RGS proteins), as well as to new insights about the regulatory role of G protein modifications (myristoylation, palmitoylation). Similar modes of regulation are now known to exist in humans. These discoveries fill some important gaps in our understanding of signal transduction, and provide an instructive example of how model organisms, like yeast, can provide new insights relevant to signal regulation in higher eukaryotes.
Criterial Features in Learner Corpora: Theory and Illustrations

One of the major goals of the Cambridge English Profile Programme is to identify ‘criterial features’ for each of the Common European Framework of Reference (CEFR) proficiency levels as they apply to English, and to assess the impact of different first languages on these features (through ‘transfer’ effects). The present paper defines what is meant by criterial features and proposes an initial taxonomy of four types. Numerous illustrations are given from our collaborative research to date on the Cambridge Learner Corpus. The benefits and challenges posed by these features for corpus linguistics and for theories of second language acquisition are briefly outlined, as are the benefits and challenges for language assessment practices and for publishing ventures that make use of them as supplements to the current CEFR descriptors.
Controlling the Synthesis and Assembly of Silver Nanocrystals for Single-Molecule Detection by SERS

ABSTRACT Detecting toxic chemical or biological ag ents in low concentrations requires a hi ghly specific sensing technique, such as surface-enhanced Raman spectroscopy (SERS). The controlled synthesis of metallic nanocrystals has provided a new class of substrates for more reliable and sensitive SERS applications. The nanocrystal shape plays a major role in designing SERS substrates for maximizing the SERS enhancement factor (EF). Assembling nanocrystals into dimers can further amplify the EF, opening the door to the possibility of single-molecule detection. Here, we briefly discuss our recent work on the synthesis of s ilver (Ag) nanocrystals and their assembly in to dimers and other reliable techniques to form hot spots with sufficiently high EF for single-molecule detection by SERS. Keywords: silver nanocrystals, surface-enhanced Raman spectroscopy, single-molecule detection, dimers, plasmon resonance 1. INTRODUCTION Single-molecule (SM) detection is the ultimate goal of many sensing techniques. It is extremely difficult to detect an analyte at a single-molecule level because its signals are typi cally weak and often obscured by the background noise. In recent years, the use of surface-enhanced Raman spectroscopy (SERS) has made in credible progress toward the detection of single molecules due to two factors.
The Coup d'Etat in The Gambia, 1994: The End of the First Republic

A coup d'etat in The Gambia abruptly ended the reign of the longest serving democratic government and head of state in Africa. This ministate of one million was renowned internationally for its tranquility at a time when the rest of the continent was mired in political instability. The coup resulted from perceived civilian government weakness, widespread feelings of relative deprivation among junior Gambian officers, and their resentment against senior Nigerian officers who controlled the army. Also, turbulence in the West Africa subregion and poor relations between the deposed Gambia and Senegal governments emboldened the junior officers to intervene. While the new regime enjoys considerable popular support, domestic and international pressures increase for a return to civilian rule. With elections promised in July 1996, some external aid has been restored, which could avert domestic financial collapse and repression.
HGF-mediated apoptosis via p53/bax-independent pathway activating JNK1

Current studies have indicated both positive and negative roles for the hepatocyte growth factor (HGF)/c-met receptor signaling system in tumor development. Recently, we have shown that HGF has the capacity to induce both growth inhibition and programmed cell death in aflatoxin-transformed (AFLB8) rat liver epithelial cells. Using the same cell line, we have now investigated a potential mechanism for HGF-induced apoptosis. Immunoblot analysis of bcl-2 gene family member (bax, bcl-2, bclX-s/l) expression showed no correlation with HGF treatment, suggesting that HGF-mediated apoptosis is bax independent. Following HGF treatment retinoblastoma protein (pRB) was present in the hypophosphorylated state. HGF treatment increased cyclin A, cyclin G1 and nuclear transcriptional factor (NFkappaB) protein expression. However, electrophoretic mobility shift analysis showed that NFkappaB activity decreased with HGF treatment. Under these apoptotic conditions, c-Jun N-terminal kinase (JNK1) and extracellular signal-regulated kinase (ERK2) were activated with lower level activation of ERK2, while no involvement of phosphatidylinositol-3 kinase was observed. Epidermal growth factor (EGF) was not protective, and actually induced cells to undergo apoptosis to a level similar to that of HGF alone or EGF/HGF in combination. These results suggest the possibility of cross-talk between HGF/c-met and EGF/EGFR signaling pathways, and the involvement of JNK1 induction in HGF-mediated apoptotic cell death.
Morphological instabilities in thin films: Evolution maps

Abstract We consider morphological instabilities in binary multilayers and the post-instability evolution of the system. The alloys with and without intermediate phase are considered, as well as the cases with stable and meta-stable intermediate phase. Using the Galerkin finite element formulation for coupled Cahn–Hilliard – elasticity problem, maps of different evolution paths are developed in the parameter space of relative thicknesses of initial phases. We consider the relative importance of elastic and chemical energy of the system and develop maps for different cases. The systems exhibit rich evolution behavior. Depending on the initial configuration (which determines the mass conservation condition), the final equilibrium varies, but even greater variety is observed in evolution paths. The paths may consist of multiple evolution steps, which may proceed at different rates. Except for few special circumstances, the instabilities are to perturbations non-homogeneous in the film plane. Post-instability evolution is essentially two-dimensional, and cannot be reduced to the one-dimensional model.
Comment on `A critical understanding of the fractal model of metabolic scaling'

Chaui-Berlinck recently published a paper in which he claims that the original West, Brown and Enquist (WBE) model for metabolic scaling ([West et al., 1997][1]) is fundamentally flawed ([Chaui-Berlinck, 2006][2]). In particular, Chaui-Berlinck asserted that \` the minimization procedure [of the
Precision agriculture—what's in our future

Abstract Introduction of new and improved technologies will speed adoption of site‐specific management practices. Integrated production systems of the future will likely include more sophisticated monitoring and control devices, remote sensing, greater use of consultants and field scouts, and interactive data management systems. Professional managers and consultants will play a major role in helping producers organize data and make management decisions. Technologies that save time, result in greater profitability, and reduce environmental risks will be rapidly adopted by producers. Future opportunities will include harvesting and marketing schemes to preserve the identify of products that have special characteristics. Remote sensing will undoubtedly play a major role in helping make site‐specific management decisions and in assessing world‐wide marketing opportunities.
PLDAPS: A Hardware Architecture and Software Toolbox for Neurophysiology Requiring Complex Visual Stimuli and Online Behavioral Control.

Neurophysiological studies in awake, behaving primates (both human and nonhuman primates) have focused with increasing scrutiny on the temporal relationship between neural signals and behaviors. Consequently, laboratories are often faced with the problem of developing experimental equipment that can support data recording with high temporal precision and also be flexible enough to accommodate a wide variety of experimental paradigms. To this end, we have developed an architecture that integrates several modern pieces of equipment, but still grants experimenters a high degree of flexibility. Our hardware architecture and software tools take advantage of three popular and powerful technologies: the PLexon apparatus for neurophysiological recordings (Plexon, Inc., Dallas TX), a DAtapixx box (Vpixx Technologies, Saint-Bruno, QC, Canada) for analog, digital, and video signal input-output control, and the PSychtoolbox MATLAB toolbox for stimulus generation (Brainard, 1997). The PL-DA-PS (“Platypus”) system is designed to support the study of the visual systems of awake, behaving primates during multi-electrode neurophysiological recordings, but can be easily applied to other related domains. Despite its wide range of capabilities and support for cutting-edge video displays and neural recording systems, the PLDAPS system is simple enough for someone with basic MATLAB programming skills to design their own experiments.
Two hydrogenases with distinct electrn-carrier specificity and subunit composition in Methanobacterium formicicum

Abstract Two hydrogenases, differing in their specificity for the electron carrier F420, were present in cell-free extracts of Methanobacterium formicicum. The two hydrogenases were resolved either by gel filtration, ion-exchange chromatography, ro by electrophoresis in polyacrylamide gel. The larger hydrogenase (designated the F420-reactive hydrogenase) showed factor F420-linked and methyl viologen-linked activities; two forms (Mr 600 000 and 380 000) were obtained from M. formicicum strain MF. The smaller enzyme (designated F420-non-reactive hydrogenase; Mr 70 000 from M. formicicum strain MF) showed only methyl viologen-linked activity. The F420-reactive hydrogenase contained subunits of Mr 42 600, 34 000 and 23 500. The F420-non-reactive hydrogenase contained subunits of Mr 48 000 and 38 000. The subunit patterns and the results of peptide mapping indicate that F420-reactive and F420-non-reactive hydrogenases are distinct enzymes. The F420-reactive hydrogenase was more stable under aerobic conditions, and both hydrogenases could be purified in air. The aerobically prepared enzymes must be incubated with a reducing agent to become active. After activation, the F420-reactive hydrogenase became unstable at 25–30°C but was stable at 0–5°C. Besides the major F420-non-reactive hydrogenase, a minor F420-non-reactive hydrogenase (Mr 145 000) was also observed in extracts of M. formicicum. The hydrogenases of M. formicicum strains MF and JF were very similar. In M. bryantii, several hydrogenase species with different electrophoretic mobilities were observed, but their properties different from those of the M. formicicum enzymes.
The HIV-1 Non-subtype B Workgroup: an international collaboration for the collection and analysis of HIV-1 non-subtype B data.

HIV-1 group M, the major pathogen responsible for the AIDS pandemic, is characterized by a wide range of genetic diversity among distinct subtypes (A-K), sub-subtypes (A1, A2; F1, F2), and circulating recombinant forms (CRF01_AE, CRF02_AG, and more). The different variants are approximately equidistantly related, and are distinct from one another across the entire genome. (Published: 23 February 2005) doi:10.1186/1758-2652-7-1-71 Full text: BioMed Central: http://www.biomedcentral.com/1758-2652/content/7/1/71 PubMed Central: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2740791/
Calculation of Feynman diagrams in space and time by stationary phase

Feynman diagrams are usually derived in relativistic space and time, and then immediately converted into energy and momentum by a Fourier transform. A method is proposed that allows keeping the external vertices at fixed locations and finite times, while the internal vertices are integrated in space-time as well. Propagators between the vertices are the well-known Bessel functions of the relativistic distance. The example of the Compton effect is worked out.
Through the Lens of Theory: Perspectives on an International Library Association

This paper discusses a study of the International Association of School Librarianship with the goal of offering a useful alternative model for studying associations: combining theory with a case-study design. While findings of the study are summarized, discussion centers on the case-study methodology and a multi-faceted theoretical framework. The theory applied is traditional and recently emerged theories of organization and the sociological theories of convergence and global integrity ethics. Aims of the paper are threefold: to present the value (to the associations and to scholars) of applying theory to the study of international associations; to provide insight into such associations; and to inspire further research in this field.
Quantum‐mechanical calculation of three‐dimensional atom–diatom collisions in the presence of intense laser radiation

A formalism is presented for describing the collision of fluorine with the hydrogen molecule in the presence of intense radiation. For a laser frequency on the order of the spin–orbit splitting of fluorine, the interaction of the molecular system with the radiation occurs at relatively long range where, for this system, the electric dipole is vanishingly small. Hence the interaction occurs due to the magnetic dipole coupling. Even so, at low collision energies a substantial enhancement of the quenching cross section is found for a radiation intensity of 1011 W/cm2.
Generation and evolution of entanglement in coupled quantum dots interacting with a quantized cavity field

The generation of entanglement between two identical, interacting quantum dots\char22{}initially in ground states\char22{}by a coherent field and the subsequent time evolution of the entanglement are studied by calculating the concurrence between the two dots. The results predict that while it is possible to generate entanglement (or entanglement of formation, as defined for a mixed state) between the two dots, at no time do the dots become fully entangled to each other or is a maximally entangled Bell state ever achieved. We also observe that the degree of entanglement increases with an increase in the photon number inside the cavity and a decrease in the dot-photon coupling. The behavior of the two-dot system, initially prepared in an entangled state and interacting with thermal light, is also studied.
Searching for information in a hypertext medical handbook

Medicine is an ideal domain for hypertext applications and research. Implementing a popular medical handbook in hypertext underscores the need to study hypertext in the context of full-text document retrieval, machine learning, and user interface issues.
Potato tuber water potential components during storage

Measurements of the water potential components in stored potato tubers were made over two storage seasons. Total potential at harvest was about −0.3 MPa and decreased to −0.5 to −0.6 MPa over the first 5 to 7 weeks of storage. During the remaining 25 weeks of storage the potential decreased another 0.1 MPa. Increases in osmotic pressure of about 0.1 MPa occurred during the first 5 to 7 weeks and turgor pressure decreased about 0.2 MPa, after which both were nearly steady. The small changes in osmotic pressure were correlated with changes in total sugars.