cssi/SciSciGPT-SciSciNet huggingface dataset:
The Arabidopsis bHLH25 and bHLH27 transcription factors contribute to susceptibility to the cyst nematode Heterodera schachtii

Successful cyst nematode parasitism depends on the formation and maintenance of feeding sites (syncytia) in host roots, and these processes are highly regulated by the interaction between the cyst nematode and the host. Using an integrated research approach and the Arabidopsis-Beta vulgaris (sugar beet) cyst nematode (Heterodera schachtii) pathosystem, we have determined that the two Arabidopsis basic helix-loop-helix transcription factors bHLH25 and bHLH27 positively influence cyst nematode parasitism. Promoter studies indicated that as early as 1 day post-inoculation, both transcription factor genes were upregulated in developing syncytia, whereas in non-infected plants, these two promoters were not found to be active in the same cells. By using yeast two-hybrid analyses and bimolecular fluorescence complementation assays, we documented that the two bHLH transcription factors can dimerize in planta. Transgenic Arabidopsis plants overexpressing either one or both of the bHLH genes exhibited altered morphology of roots and shoots, as well as an increased susceptibility to H. schachtii. bhlh25 or bhlh27 single mutants were without strong phenotypes, presumably because of functional redundancies in this gene family. However, the bhlh25 bhlh27 double mutant was less susceptible to H. schachtii, confirming an important conducive role of the co-expression of both transcription factor genes for cyst nematode parasitism. Our results document an example of pathogen-induced ectopic co-expression of two regulatory genes to enhance pathogen success, although these transcription factors apparently do not function in concert in non-infected plants. This is an intriguing biological phenomenon that highlights the complexity of obligate biotrophic plant-pathogen interactions, like those of cyst nematodes.
Healing Powers and Modernity: Traditional Medicine, Shamanism, and Science in Asian Societies.

Healing Powers and Modernity: Traditional Medicine, Shamanism, and Science in Asian Societies. Linda H. Connor and Geoffrey Samuel. eds. Westport, CT: Bergin and Garvey, 2001. 296 pp.
Uncertainty corpus: Resource to study user affect in complex spoken dialogue systems

We present a corpus of spoken dialogues between students and an adaptive Wizard-of-Oz tutoring system, in which student uncertainty was manually annotated in real-time. We detail the corpus contents, including speech files, transcripts, annotations, and log files, and we discuss possible future uses by the computational linguistics community as a novel resource for studying naturally occurring user affect and adaptation in complex spoken dialogue systems.
Efficient and distributable methods for solving the multiagent plan coordination problem

Coordination can be required whenever multiple agents plan to achieve their individual goals independently, but might mutually benefit by coordinating their plans to avoid working at cross purposes or duplicating effort. Although variations of such problems have been studied in the literature, there is as yet no agreement over a general characterization of them. In this paper, we formally define a common coordination problem subclass, which we call the Multiagent Plan Coordination Problem, that is rich enough to represent a wide variety of multiagent coordination problems. We then describe a general framework that extends the partial-order, causal-link plan representation to the multiagent case, and that treats coordination as a form of iterative repair of plan flaws between agents. We show that this algorithmic formulation can scale to the multiagent case better than can a straightforward application of the existing plan coordination techniques, highlighting fundamental differences between our algorithmic framework and these earlier approaches. We then examine whether and how the Multiagent Plan Coordination Problem can be cast as a Distributed Constraint Optimization Problem (DCOP). We do so using ADOPT, a state-of-the-art system that can solve DCOPs in an asynchronous, parallel manner using local communication between individual computational agents. We conclude with a discussion of possible extensions of our work.
Integration in Finite Terms with Special Functions: A Progress Report

Since R. Risch published an algorithm for calculating symbolic integrals of elementary functions in 1969, there has been an interest in extending his methods to include nonelementary functions. We report here on the recent development of two decision procedures for calculating integrals of transcendental elementary functions in terms of logarithmic integrals and error functions. Both of these algorithms are based on the Singer, Saunders, Caviness extension of Liouville's theorem on integration in finite terms [Ssc81]. Parts of the logarithmic integral algorithm have been implemented in Macsyma and a brief demonstration is given.
Bioptic telescopes meet the needs of drivers with moderate visual acuity loss.

PURPOSE: Visually impaired people are permitted to use bioptic telescopes for driving in many states in the United States. However, it has been suggested that the telescope is used only to meet the visual acuity criteria for licensure. In this study, a survey was used to establish the extent to which bioptic telescopes are used by and meet the driving needs of people with moderately reduced visual acuity. METHODS: A cross-sectional survey of a convenience sample of 58 bioptic drivers was administered by telephone interview. Bioptic telescope usage patterns were quantified with questions designed specifically for the study. Driving patterns were quantified by use of the Driving Habits Questionnaire. Subjects were recruited from four sources across the United States to ensure a range of bioptic training and driving experience. RESULTS: The majority (74%) rated the bioptic telescope as very helpful, and almost all (90%) would continue to use it for driving, even if it were not required for driving licensure; however, only 62% reported always wearing the bioptic when driving. Subjects had relatively unrestricted driving habits, driving a mean of 222 +/- 211 miles per week, and 85% aged < or =65 years drove to work. With the exception of driving in rain, in bright sunlight, and at night, there was little difficulty with driving in a variety of situations, and levels of driving avoidance due to vision impairment were low (<10%). CONCLUSIONS: The bioptic telescope met the (self-reported) driving needs of the majority of visually impaired drivers in this survey and was found to be a useful aid for tasks requiring resolution of detail.
Compromise and accommodation in ecotin, a dimeric macromolecular inhibitor of serine proteases.

Abstract Ecotin is a dimeric serine protease inhibitor from Escherichia coli which binds proteases to form a hetero-tetramer with three distinct interfaces: an ecotin-ecotin dimer interface, a larger primary ecotin-protease interface, and a smaller secondary ecotin-protease interface. The contributions of these interfaces to binding and inhibition are unequal. To investigate the contribution and adaptability of each interface, we have solved the structure of two mutant ecotin-trypsin complexes and compared them to the structure of the previously determined wild-type ecotin-trypsin complex. Wild-type ecotin has an affinity of 1 nM for trypsin, while the optimized mutant, ecotin Y69F, D70P, which was found using phage display technologies, inhibits rat trypsin with a Ki value of 0.08 nM. Ecotin 67-70A, M84R which has four alanine substitutions in the ecotin-trypsin secondary binding site, along with the M84R mutation at the primary site, has a Ki value against rat trypsin of 0.2 nM. The structure of the ecotin Y69F, D70P-trypsin complex shows minor structural changes in the ecotin-trypsin tetramer. The structure of the ecotin 67-70A, M84R mutant bound to trypsin shows large deviations in the tertiary and quaternary structure of the complex. The trypsin structure shows no significant changes, but the conformation of several loop regions of ecotin are altered, resulting in the secondary site releasing its hold on trypsin. The structure of several regions previously considered to be rigid is also significantly modified. The inherent flexibility of ecotin allows it to accommodate these mutations and still maintain tight binding through the compromises of the protein-protein interfaces in the ecotin-trypsin tetramer. A comparison with two recently described ecotin-like genes from other bacteria suggests that these structural and functional features are conserved in otherwise distant bacterial lineages.
Locus of Control and Achievement of Nigerian School-Age Children

Summary To investigate the relationship between locus of control and academic achievement and motivation of school-age children of Nigeria, the short form of Nowicki-Strickland Personal Reaction Survey was administered to 180 Nigerian children ranging in age from 9 to 13. Their motivation was assessed by teacher's ratings. Grades received in mathematics and reading/language were used as a measure of academic achievement. Findings indicated that internality was significantly related to academic achievement, but not to motivation. Results of a 2 (sex) × 4 (grade scores) analysis of variance indicate that the students who received higher grades perceived themselves as more internally oriented. No sex differences were found for any of the three measures used. Results support the conclusion that the relationship between academic achievement and locus of control are comparable cross-culturally.
Longitudinal dispersion in a packed bed

A mixing length model for longitudional dispersion is develoopd to provide insight into the fundamental difference between axial and radial mixing. (J.R.D.)
Analytical models and laboratory measurements of the soil–tool interaction force to push a narrow tool through JSC-1A lunar simulant and Ottawa sand at different cutting depths

Abstract Excavation equipment for developing NASA’s lunar outpost must be carefully designed to reduce launch cost, minimize operation cost, and enhance reliability. Excavation equipment requires knowledge of the stresses and strains in the equipment caused by the forces experienced during excavation. The types of excavation anticipated indicate that blade tools would move the most material. There are several analytical models available to predict forces from blade tools interacting with soil; however, it is not clear which if any, can predict lunar excavation forces precisely enough. Consequently, we measured the forces to push narrow (2.5-cm wide) square and round rods through a control material, Ottawa sand, and JSC-1A lunar mare regolith simulant at different cut depths in a controlled laboratory setting. The measurement results were compared with the forces predicted by eight analytical models. The Zeng, Luth and Wismer, and the Qinsen and Suren models fit the measurements best, considering that our study was limited to pushing stimulant and sand with small rods. The results show that depth of cut has a dramatic effect on the soil–tool interaction forces. Consequently, lunar missions should use a series of shallow cuts to reduce equipment size and power requirements.
Two Professors Critique the Representations of Africans and African Americans in Picture Books

The authors examined the sociocultural representations of black children in picture books. Three critical perspectives were used to examine 23 picture books containing black characters. Questions used in this critical analysis were derived from sociocultural implications of implicit messages within texts, critical literacy, and cultural and social reader response theories. Our aim was to determine what stories are being told and how two adults, one black and one white, interpret these stories. We also considered the importance of analyzing these picture books when using them in elementary classrooms. We found that our different cultural and racial backgrounds influenced our response to a number of the books, clearly pointing to the advantage of discussing children's books with colleagues of different races.
Quenching as a four-dimensional experiment: Application to the multi-domain binding of cytochrome c by cytochrome c peroxidase

Abstract We have presented an expanded view of quenching titration experiments as generating four-dimensional data sets, yielding not curves but 2-D surfaces. To determine the stoichiometry and reactivity for the [C c P, C c ] complex, quenching titration experiments were performed using both the conventional substitution mode (C-mode) where Zn-substituted cytochrome c peroxidase (ZnC c P) is the photoprobe and the inverse substitution mode (I-mode) where Zn-substituted cytochrome c (ZnC c ) is the photoprobe. For both modes, titrations were performed in either the normal (N) way where aliquots of the quencher are added into a solution containing a fixed concentration of the probe, or the reverse (R) way where aliquots of the probe are titrated into a solution where the concentration of the quencher is fixed. This leads to the expansion of quenching protocols to include four types of titrations: C N , C R , I N , and I R . Together, the four titrations demonstrate that: (i) C c reacts at two distinct and non-exclusive surface domains of C c P; (ii) two molecules of C c can bind simultaneously to C c P; and (iii) the ternary complex is more reactive than the binary complex for the heme-heme ET reaction.
Time development of diffusion-limited oxidation profiles in a radiation environment

We have previously presented a quantitative model that combines diffusion and kinetic expressions with chemical/mechanical property relationships to predict the time development of diffusion-limited oxidation profiles in polymers. This model was shown to be applicable to thermal aging environments and should be generally applicable to environmental stresses for which total damage to the material is directly proportion to total exposure time. In this work, we use a fluorocarbon elastomer to demonstrate applicability of the model to ionizing-radiation environments.
FUROCOUMARIN‐PHOTOSENSITIZEDHYDROXYLATION OF GUANOSINE IN RNA AND DNA

— Guanosine hydroxylation was used as a marker for assessing photooxidation of DNA and RNA sensitized by monofunctional and bifunctional furocoumarins. DNA or RNA, treated with sensitizer and UVA light, was enzymatically hydrolyzed, dephosphorylated and then analyzed by reversed-phase HPLC with electrochemical detection. Hydroxylated guanosine, i.e. 8-hydroxy-2′-deoxyguanosine (8-OHdG) or 8-hydroxyguanosine (8-OHG), was quantitated. 3-Carbethoxypsoralen (3-CP) was found to be an efficient photosensitizer for oxidation of guanosine in DNA, resulting in conversion of up to 0.4% of guanosine residues to 8-OHdG. In contrast, dramatically lower levels of guanosine hydroxylation were observed in 3-CP-photosensitized RNA. Psoralen was found to be a more efficient photosensitizer than angelicin in both DNA and RNA. Additional studies of oxidation of 3-CP-photosensitized DNA indicated that double-stranded DNA is 10 times more susceptible to photooxidation than single-stranded DNA, implicating 3-CP binding to DNA as an important mechanistic step in photooxidation of guanosine. The effects of D2O and degassing with argon on photooxidation of guanosine in DNA sensitized by 3-CP were inconsistent with a mechanism involving 1O2. In addition, chelation of adventitious metal ions present in preparations of DNA photosensitized by 3-CP had no effect on hydroxylation of guanosine.
Potato improvement through parental line breeding

The potato is the major horticultural crop in the North Central States. It has more characters of economic importance than most other crops. These characters are scattered among the many cultivated and non-cultivated tuber-bearing species of Solanum which number approximately 250. The asexually propagated clones now being used in potato breeding programs are genotypes which segregate more or less for most, if not all of their important characters. This means that there are hundreds of genes influencing these characters and segregating in each cross. With only 20 genes segregating in a cross slightly over a million combinations are possible. Therefore if any specific combination of these 20 genes is the character combination desired, one could expect it to appear about once in each million individuals. This means that a population of 5 million is likely to be required in order to be reasonably sure that the desired character combination will appear in the population. The magnitude of the task of growing and screening segregates of that number is better appreciated when one realizes that the total annual seedling population of the potato breeding programs in the North Central region does not currently exceed 100,000. The production of parental lines possessing high homozygosity for one or several desirable characters will be of great value since the size of populations necessary for screening will be reduced and the time required for the production of new varieties will probably be shortened. It is apparently necessary to obtain characteristics from other Solanum species which are now considered mandatory for modern potato varieties. Many of these species have not, as yet, been evaluated for genetic complexity or for combining ability with 5". tuberosum. Further breeding research is required in order to determine the most effective ways of developing lines homozygous for the genes governing several characters. This is a project for concerted action by the several states because the results will be of value to all programs. Numerous varieties with meritorious characters of various types have been made commercially available in recent years with the awareness that each addition of another desired character in a new variety tends to pyramid the complexity and volume of the breeding work. This relationship emphasizes the necessity for the purification of the building materials for use in developing modern potato varieties. aAccepted for publication June 12, 1956.
Flux states for the infinite-U limit of the Hubbard model

Pour le dopage fini, δ, relatif au demi-remplissage, on montre dans une formulation de l'operateur auxilliaire de l'approximation du champ moyen, pour la limite U-infini (J=0) du modele de Hubbard bidimensionnel que les spinons generent un flux magnetique fictif auquel les bonons sont sujets et vice versa. Pour un faible dopage, l'etat fondamental est un etat de flux avec 1-δ=2P/q, ou P/q est une fraction rationnelle, et le flux par plaquette etant φ=(P/q)φ, ou φ est le quantum de flux. Ce phenomene peut etre regarde comme une instabilite de Peierls collective ou une symetrie statistique brisee
Patient–oncologist communication in advanced cancer: predictors of patient perception of prognosis

Goals of work Advanced cancer patients’ perceptions of prognosis, which are often overly optimistic compared to oncologist estimates, influence treatment preferences. The predictors of patients’ perceptions and the effect of oncologist communication on patient understanding are unclear. This study was designed to identify the communication factors that influence patient–oncologist concordance about chance of cure.
Von recklinghausen's disease associated with duodenal somatostatinoma: Contrast of duodenal versus pancreatic somatostatinomas

A case of Von Recklinghausen's disease with duodenal somatostatinoma is reported. A search of the world's literature revealed 27 patients with Von Recklinghausen's disease associated with an immunohistologically proved duodenal somatostatinoma. Twenty-nine cases of duodenal somatostatinoma not associated with Von Recklinghausen's disease and 32 cases of pancreatic somatostatinomas have been identified for comparison. While their histology may be similar in many respects, the duodenal and pancreatic somatostatinomas show significant differences, especially in hormonal and growth behaviors. In contrast to its pancreatic counterpart, the duodenal somatostatinoma is frequently associated with Von Recklinghausen's disease, is seldom associated with a recognizable "somatostatin syndrome," often contains psammoma bodies, and is less frequently associated with demonstrable metastases at the time of operation.
Multidimensional Fechnerian scaling: pairwise comparisons, regular minimality, and nonconstant self-similarity

Stimuli presented pairwise for same-different judgments belong to two distinct observation areas (different time intervals and/or locations). To reflect this fact the underlying assumptions of multidimensional Fechnerian scaling (MDFS) have to be modified, the most important modification being the inclusion of the requirement that the discrimination probability functions possess regular minima. This means that the probability with which a fixed stimulus in one observation area (a reference) is discriminated from stimuli belonging to another observation area reaches its minimum when the two stimuli are identical (following, if necessary, an appropriate transformation of the stimulus measurements in one of the two observation areas). The remaining modifications of the underlying assumptions are rather straightforward, their main outcome being that each of the two observation areas has its own Fechnerian metric induced by a metric function obtained in accordance with the regular variation version of MDFS. It turns out that the regular minimality requirement, when combined with the empirical fact of nonconstant self-similarity (which means that the minimum level of the discrimination probability function for a fixed reference stimulus is generally different for different reference stimuli), imposes rigid constraints on the interdependence between discrimination probabilities and metric functions within each of the observation areas and on the interdependence between Fechnerian metrics and metric functions belonging to different observation areas. In particular, it turns out that the psychometric order of the stimulus space cannot exceed 1.
Changes in quantitative 3D shape features of the optic nerve head associated with age

Optic nerve head (ONH) structure is an important biological feature of the eye used by clinicians to diagnose and monitor progression of diseases such as glaucoma. ONH structure is commonly examined using stereo fundus imaging or optical coherence tomography. Stereo fundus imaging provides stereo views of the ONH that retain 3D information useful for characterizing structure. In order to quantify 3D ONH structure, we applied a stereo correspondence algorithm to a set of stereo fundus images. Using these quantitative 3D ONH structure measurements, eigen structures were derived using principal component analysis from stereo images of 565 subjects from the Ocular Hypertension Treatment Study (OHTS). To evaluate the usefulness of the eigen structures, we explored associations with the demographic variables age, gender, and race. Using regression analysis, the eigen structures were found to have significant (p < 0.05) associations with both age and race after Bonferroni correction. In addition, classifiers were constructed to predict the demographic variables based solely on the eigen structures. These classifiers achieved an area under receiver operating characteristic curve of 0.62 in predicting a binary age variable, 0.52 in predicting gender, and 0.67 in predicting race. The use of objective, quantitative features or eigen structures can reveal hidden relationships between ONH structure and demographics. The use of these features could similarly allow specific aspects of ONH structure to be isolated and associated with the diagnosis of glaucoma, disease progression and outcomes, and genetic factors.
The Phenotypes of Pluripotent Human Hepatic Progenitors

Human livers contain two pluripotent hepatic progenitors, hepatic stem cells and hepatoblasts, with size, morphology, and gene expression profiles distinct from that of mature hepatocytes. Hepatic stem cells, the precursors to hepatoblasts, persist in stable numbers throughout life, and those isolated from the livers of all age donors from fetal to adult are essentially identical in their gene and protein expression profiles. The gene expression profile of hepatic stem cells throughout life consists of high levels of expression of cytokeratin 19 (CK19), neuronal cell adhesion molecule (NCAM), epithelial cell adhesion molecule (EpCAM), and claudin-3 (CLDN-3); low levels of albumin; and a complete absence of expression of α-fetoprotein (AFP) and adult liver-specific proteins. By contrast, hepatoblasts, the dominant cell population in fetal and neonatal livers, decline in numbers with age and are found as <0.1% of normal adult livers. They express high levels of AFP, elevated levels of albumin, low levels of expression of adult liver-specific proteins, low levels of CK19, and a loss of NCAM and CLDN-3. Mature hepatocytes lack expression altogether of EpCAM, NCAM, AFP, CLDN-3, cytokeratin 19, and have acquired the well-known adult-specific profile that includes expression of high levels of albumin, cytochrome P4503A4, connexins, phosphoenolpyruvate carboxykinase, and transferrin. Thus, hepatic stem cells have a unique stem cell phenotype, whereas hepatoblasts have low levels of expression of both stem cell genes and genes expressed in high levels in mature hepatocytes.
In Vivo Evaluation of Vena Caval Filters: Can Function Be Linked to Design Characteristics?

Purpose: To compare the five vena caval filters marketed in the United States and one investigational vena caval filter and to determine whether there is an association between their design and their in vivo function.
A modulatory role of central cholinergic transmission in control of the 10-Hz rhythm in sympathetic nerve discharge ☆

Abstract In 43 urethane-anesthetized or decerebrate, baroreceptor-denervated cats, spectral analysis showed that most of the power in sympathetic nerve discharge (SND) was at frequencies n = 6). In contrast, the naturally occurring 10-Hz rhythm that appeared in SND in other experiments was atropine-insensitive ( n = 6). The data indicate that central muscarinic cholinergic transmission is not essential for the naturally occurring 10-Hz rhythm. Nonetheless, facilitation of cholinergic transmission can induce a 10-Hz rhythm.
Intrauterine Growth Restriction Increases Fetal Hepatic Gluconeogenic Capacity and Reduces Messenger Ribonucleic Acid Translation Initiation and Nutrient Sensing in Fetal Liver and Skeletal Muscle

Expression of key metabolic genes and proteins involved in mRNA translation, energy sensing, and glucose metabolism in liver and skeletal muscle were investigated in a late-gestation fetal sheep model of placental insufficiency intrauterine growth restriction (PI-IUGR). PI-IUGR fetuses weighed 55% less; had reduced oxygen, glucose, isoleucine, insulin, and IGF-I levels; and had 40% reduction in net branched chain amino acid uptake. In PI-IUGR skeletal muscle, levels of insulin receptor were increased 80%, whereas phosphoinositide-3 kinase (p85) and protein kinase B (AKT2) were reduced by 40%. Expression of eukaryotic initiation factor-4e was reduced 45% in liver, suggesting a unique mechanism limiting translation initiation in PI-IUGR liver. There was either no change (AMP activated kinase, mammalian target of rapamycin) or a paradoxical decrease (protein phosphatase 2A, eukaryotic initiation factor-2 alpha) in activation of major energy and cell stress sensors in PI-IUGR liver and skeletal muscle. A 13- to 20-fold increase in phosphoenolpyruvate carboxykinase and glucose 6 phosphatase mRNA expression in the PI-IUGR liver was-associated with a 3-fold increase in peroxisome proliferator-activated receptor-gamma coactivator-1 alpha mRNA and increased phosphorylation of cAMP response element binding protein. Thus PI-IUGR is-associated with reduced branched chain amino acid uptake and growth factors, yet up-regulation of proximal insulin signaling and a marked increase in the gluconeogenic pathway. Lack of activation of several energy and stress sensors in fetal liver and skeletal muscle, despite hypoxia and low energy status, suggests a novel strategy for survival in the PI-IUGR fetus but with potential maladaptive consequences for reduced nutrient sensing and insulin sensitivity in postnatal life.
Physiological bases of the synchronized population spikes and slow wave of the magnetic field generated by a guinea-pig longitudinal CA3 slice preparation

Abstract Objective: The physiological bases of evoked magnetic fields were examined in a guinea-pig hippocampal slice preparation, motivated by new concepts in central nervous system (CNS) electrophysiology brought about by discoveries of active conductances in the dendrites and soma of neurons. Methods: Their origins were elucidated by comparing them with intracellular and extracellular field potentials. Results: With excitatory synaptic transmissions blocked, the magnetic signal elicited by an electrical stimulus applied to the pyramidal cell layer consisted of a spike and a depolarizing afterpotential-like waveform. With the excitatory synaptic transmissions intact, but with inhibitory synaptic transmissions blocked, the magnetic signal was bi- or triphasic depending on whether the cell layer or the apical dendrite area of the pyramidal cells was, respectively, depolarized. In both cases the signal consisted of a train of synchronized population spikes superimposed on a brief wave followed by a longer, slow wave. The spike train was correlated with synaptically mediated intracellular spikes. The underlying currents for the slow wave were directed from the apical to the basal side for both types of stimulation. It was most likely generated by depolarization of the apical dendrites, caused by recurrent excitatory synaptic activation. Conclusions: This analysis illustrates how synaptic connections and intrinsic conductances in a disinhibited mammalian CNS structure can generate spikes and waves of the magnetic field and electrical potential.
Effect of sample matrix on the fundamental properties of the inductively coupled plasma

Abstract In the inductively coupled plasma (ICP), the emission intensities of atomic and ionic spectral lines are controlled by fundamental parameters such as electron temperature, electron number density, gas-kinetic temperature, analyte atom and ion number densities, and others. Accordingly, the effect of a sample matrix on the analyte emission intensity in an ICP might be attributable to changes in these fundamental parameters caused by the matrix elements. In the present study, a plasma imaging instrument that combines Thomson scattering, Rayleigh scattering, laser-induced fluorescence and computed tomography has been employed to measure the above-mentioned parameters in the presence and absence of matrix elements. The data thus obtained were all collected on a spatially resolved basis and without the need for Abel inversion. Calcium, strontium and barium served as analytes, while lithium, copper and zinc were introduced as matrix elements. Comparing the data with and without the matrix elements allows us to determine the extent to which each fundamental parameter changes in the presence of a matrix element, and to better understand the nature of the matrix effects that occur in the ICP. As has been seen in previous studies with different matrix elements, ion emission and ion number densities follow opposite trends when matrix interferents are introduced into the plasma: ion emission is enhanced by the presence of matrix interferents while ion concentrations are lowered. These changes are consistent with a shift from collisional deactivation to radiative decay of excited-state analyte species.
TH-E-330A-03: Reduction of Ring Artifacts in Cone Beam CT: Artifact Detection and Correction for Flat Panel Imagers

Purpose: Defective pixels in a flat panel detector may be characterized by a nonlinear signal response drastically different from those in the neighboring pixels. They could lead to ring artifacts in cone beam CT. In this presentation, we will describe and demonstrate the use of a filter based calibration technique to detect these pixels. In addition, we will employ this technique as a flat field correction method to correct nonlinear signal response. Methods and Materials: To force the signal responses of all pixels to vary smoothly without sudden changes, we acquired images at fixed mAs but with various filtrations. Each filtered image is fitted to a smooth surface whose values are close to those of normal pixels but vary smoothly in the image. The ratios of the surface fit values to the original values were then computed on a pixel‐by‐pixel basis and used to map pixel values during subsequent image acquisition. This mapping would compensate for the nonlinear signal response associated with the defective pixels thus eliminating the ring artifacts. Using the surface fits as the reference, defective pixels were detected by automatic thresholding. Results: Using filter based calibration, defective (∼0.035 %) pixels were successfully detected and corrected for. Therefore, ring artifacts were largely eliminated in cone beam CTimages. A reduction in patterned noise artifacts in the projection images was also observed. The automated surface fitting procedure was found to be robust. Conclusions: Although the conventional flat field correction addresses non‐uniform response across the detector, artifacts may still form as the pixel response varies with the beam quality and signal intensity. The filter based calibration procedure was successfully used to detect and correct for these artifacts. This work was supported in part by a research grant EB00117 from the NIH‐NIBIB and a research grant CA104759 from the NIH‐NCI.
Molecular Recognition by Thrombin. Role of the Slows→Fast Transition, Site-specific Ion Binding Energetics and Thermodynamic Mapping of Structural Components

Abstract The interaction of thrombin with the potent natural inhibitor hirudin is controlled in a complex fashion by the binding of Na+ and Cl- to the enzyme and allosteric transitions. Binding of hirudin is positively linked to Na+ binding, but is opposed in a competitive fashion by the binding of Cl-. Since Na+ binding induces the slow→fast transition of thrombin, it follows from linkage principles that hirudin binds to the fast form with higher affinity. Hence, the slow→fast transition is a key component of molecular recognition of hirudin by thrombin. We propose a three-step mechanism for molecular recognition of hirudin by thrombin, which is also relevant for recognition of fibrinogen and possibly the platelet receptor and thrombomodulin. First, the C-terminal acidic tail of hirudin binds to the fibrinogen recognition site of thrombin displacing one Cl ion from the thrombin surface. Then, the enzyme undergoes a conformational transition that gives rise to increased accessibility of the catalytic pocket to small synthetic substrates through movement of the Trp148 loop. The changes in the catalytic moiety triggered allosterically by binding to the fibrinogen recognition site are linked to the uptake of Na+ and are similar to, if not identical with, those observed in the Na+-induced slow→fast transition. Finally, the compact N-terminal domain is accommodated in the region surrounding the catalytic pocket. Hirudin binding is also used as a probe of site-specific ion-binding interactions of Na+ and Cl- with the enzyme, characterized by cooperativity between the Na+ and Cl- binding domains. The structural components directly involved or linked to Na+ and Cl- binding have been explored in terms of free energy perturbations of the binding of hirudin and a number of ligands. The fibrinogen recognition site stores most of the free energy of coupling with Cl- binding, while regions surrounding the access to the catalytic pocket provide most of the free energy of coupling with Na+ binding and the slow→fast transition of thrombin. It is concluded that thrombin is an allosteric enzyme that exists in two forms, slow and fast, and that the allosteric transition slow→fast represents the key element of molecular recognition of important physiological substrates. The allosteric nature of the enzyme also enables different structural domains to communicate and give rise to biological function.
A meta-analysis exploring the relationship between 12-step attendance and adolescent substance use relapse.

This article describes results from a systematic review and meta-analysis of research exploring the relationship between adolescent 12-step program attendance and relapse after treatment. A systematic literature search was conducted resulting in 364 unduplicated abstracts to review. Four studies were eligible and were double-coded for variables. Outcome effect sizes were then analyzed in a random-effects model. The overall mean effect indicated beneficial results for adolescents who attended 12-step programs posttreatment. These findings support the clinical recommendation that adolescents attend 12-step programs, yet the findings highlight the need for future research among this population that clearly documents variables related to recovery outcomes.
Contribution of Weather Variables to Genotype X Environment Interaction in Grain Sorghum1

Genotype × environment (GE) interactions are a major problem in plant breeding programs that involve testing in diverse environments. These interactions can reduce progress from selection. Few studies have characterized the effects of weather variables on GE interactions in sorghum (Sorghum bicolor [L.] Moench). The present investigation estimated the contribution of environmental index, (Ȳ, or mean yield of all cultivars in jth environment minus Ȳ. xor overall mean yield for all cultivars and all environments), rainfall, minimum and maximum temperature, and relative humidity, to GE interaction. Yield means of 5 full-season and 10 medium-season grain sorghum hybrids grown during 1986—1988 at four locations were used in the study. The GE interaction was significant and partitioned into σ2i, components assignable to each genotype. Weather variables (covariates) were used to remove heterogeneity from the GE interaction. The remainder of the GE interaction variance was partitioned into variance components (s2i) assignable to each genotype. In both maturity groups, the environmental index removed most, although non-significant, heterogeneity from the GE interaction sums of squares. Of all weather variables, preseason and seasonal rainfall contributed most to the GE interaction sums of squares.
Insulin-like growth-factor binding protein (IGFBP) serum levels and hepatic IGFBP-2 and -3 mRNA expression in diabetic and insulin-treated swine (Sus scrofa).

1. 1. Diabetes had no significant effect on IGFBP-3 message and serum levels however, subsequent insulin treatment caused more than a two-fold increase in both hepatic IGFBP-3 mRNA and serum levels above controls (P < 0.05). 2. 2. The induction of diabetes in pigs significantly increased the steady state levels of IGFBP-2 mRNA in the liver of young swine (P < 0.05). 3. 3. Both liver message and serum IGFBP-2 were reduced to control levels with insulin therapy. 4. 4. We report here that in addition to its affects on IGFBP-2, insulin is involved in the regulation of IGFBP-3 expression.
Decoherence in quantum walks on the hypercube

We study a natural notion of decoherence on quantum random walks over the hypercube. We prove that this model possesses a decoherence threshold beneath which the essential properties of the hypercubic quantum walk, such as linear mixing times, are preserved. Beyond the threshold, we prove that the walks behave like their classical counterparts.
Variable Property Nusselt Numbers in a Channel with Pin Fins

Nusselt numbers and friction factors are presented that show the effects of temperature ratio and variable properties in a rectangular channel with pin fins and an aspect ratio of 8. The ratio of air inlet stagnation temperature to local surface temperature T 0i /T w varies from 0.68 to 0.93, and Reynolds numbers based on channel height range from 1.8 x 10 4 to 3.38 × 10 4 . The pins are placed in 12 rows, with pin diameter and spacing between adjacent pins in both directions all equal to the channel height. Ratios of globally averaged Nusselt numbers to baseline, constant-property Nusselt numbers, Nu/Nu 0,cp , increase by about 35% as the temperature ratio T 0i /T w decreases, provided that Reynolds number Re H is approximately constant and that the base areas beneath the pins are not considered. When heat transfer from the pin fins is also included, this increase is about the same. Friction factor ratios f/f 0,cp decrease as T 0i /T w decreases over this same range of values. Such global Nusselt number changes are a result of local Nusselt number ratio increases with decreasing temperature ratio, which are especially pronounced beneath the wake and shear layers that are present downstream of each pin and beneath the horseshoe vortex that forms just upstream of each pin fin.
Optical classification of natural waters 1

A technique has been developed that leads to an optical classification of natural waters in terms of the dissolved and suspended biogenous material present. As a first approximation, this classification has been made in terms of the total chlorophyll-like pigment concentration. A relationship between the spectral diffuse attenuation coefficient for irradiance and the chlorophyll-like pigment concentration has been found with spectral irradiance data from diverse types of ocean waters. The specific spectral attenuation coefficient due to phytoplankton is shown to be consistent with laboratory measurements of the diffuse absorption coefficient of various lot cultures of phytoplankton.
17 beta-Estradiol Induced Prostatitis in the Rat is an Autoimmune Disease

AbstractPurpose: Studies suggest that alteration in steroid hormone levels may be one of the factors causing nonbacterial prostatitis (NBP) in rats. We hypothesized that hormonally induced prostatitis in the rat may be an autoimmune disease. Studies were carried out to prove this hypothesis.Materials and Methods: We injected 17 beta-estradiol (E2; 250 microgram/kg. subcutaneously) or vehicle into 1-year-old male rats for 30 days, and isolated and cultured the splenocytes in the presence of con-A (Experiment 1). Approximately 107 splenocytes were adoptively transferred into young naive syngeneic rats. To find out whether or not the inflammation is mediated by T-lymphocytes, a pure population of T-lymphocytes from E2 -treated 3-month-old rats was injected into young naive syngeneic rats (Experiment 2). To rule out the possibility that the inflammation was due to con-A itself, we cross-linked some T-cells with anti-CD3 antibody before adoptive transfer (Experiment 2).Results: The recipients of splenocytes fr...
The Effects of Using Calculators to Reduce the Computational Burden on a Standardized Test of Mathematics Problem Solving

Problem solving is a key skill in mathematics education. Thus, it is important to be able to assess students' proficiencies as problem solvers. The Quantitative Thinking Subtest (Test Q) of the Iowa Tests of Educational Development is a test of problem solving ability. However, if this test is to be considered a pure measure of problem solving ability, it must be demonstrated that this test does not measure other factors such as computational ability. To this end, a study was designed in which two groups of students took Test Q; one group using calculators to eliminate the need for computation, and the other just using paper and pencil to solve the problems. It was found that after controlling for differences in mathematical ability, the two groups did not differ in their scores on Test Q. This result seemed to support the validity of Test Q as a test of problem solving.
Mirror Surface Aberrations And Mixing Efficiency

The mixing efficiency of a heterodyne laser radar system is a critical performance factor. This paper deals with a special system configuration whereby a laser radar beam is directed by a remote agile mirror. In order to track the target, the mirror surface normal must point halfway between the vector direction to the target and the laser radar's telescope aperture plane normal. Ideally, the mirror's surface must be perfectly flat to avoid any distortion of the return target signal. The effect of mirror surface aberrations upon the heterodyne laser radar's mixing efficiency, and therefore upon the system signal-to-noise ratio, is the the subject of this paper. A computer model is used is used to introduce the spatial wavefront distortions upon the return plane wave signal (representing a point target) and to represent the field pattern on the detector plane using a 2-D discrete Fourier transform. The relative mixing efficiency is calculated for several classical types of mirror surface aberrations using Zernike polynomial representations. Effects such as thermal gradients across the face of the mirror, thermal gradients between the front and the back of the mirror and gravity loading of the mirror are modeled. The mirror surface height aberrations are expressed in wavelengths in order to increase the general applicability of the results. The imperfect mirror surface acts like a phase grating which changes the spatial phase of the reflected plane wave return signal. Mixing efficiency is computed relative to the mixing efficiency that would be obtained with a perfect undistorted plane wave return signal. It is assumed that the local oscillator produces a uniform intensity and constant spatial phase plane wave signal at the telescope aperture plane. The mirror diameter is assumed to be 2.4 times larger than the telescope aperture diameter. This keeps the telescope aperture fully illuminated for a target angles of up to 65 degrees with respect to the mirror surface normal. Results are presented for both a finite extent and infinite extent detector aperture. Example diffraction patterns are plotted in a 3-D surface plot form to provide a visual appreciation of the effects of the mirror surface aberrations.
ADULT RESPIRATORY DISTRESS SYNDROME (ARDS) IN NEONATES: A CLINICAL SYNDROME

Since 1984 we have cared for 11 neonates with severe respiratory distress whose clinical characteristics appear distinctive: 1) full-term by obstetric and Dubowitz criteria (median 39 wks, range 37-42; median BW 2950g, range 2610-4360), 2) diffuse alveolar disease radiographically, 3) requiring FiO2 1.0 and mechanical ventilation to maintain paO2 50, 4) absence of other conditions known to produce a similar clinical profile. No mothers were diabetic or Rh-sensitized. Blood cultures and latex agglutination bacterial antigen studies were negative in all. None had aspirated meconium. Two-dimensional echocardiography and simultaneous pre- and postductal ABGs showed no evidence of cyanotic congenital heart disease or extrapulmonary right-to-left mix. Among the 11, 5 had 5 minute Apgar scores ≤5, 8 had evidence of fetal distress, 5 had initial hematocirts 20 torr. Among 7 infants who underwent trials of increased PEEP to ≥6 cm H2O (range 6-10) without other concurrent changes in ventilator settings, 6 responded with prompt increases in paO2 >20 torr (median 68, range 22-136), despite resultant mean airway pressure (PAW) being lower than previously unsuccessful PAWs in 4 of 6. We suggest that ARDS is a distinctive clinical entity in neonates. A trial of PEEP ≥6 cm H2O should be considered in full-term infants with severe respiratory distress in whom other causes can be excluded.