cssi/SciSciGPT-SciSciNet huggingface dataset:
How Transcription Initiation Can Be Regulated in Bacteria

Most activators of transcription initiation that affect s70-containing RNA polymerase (RNAP) are sequence-specific DNA-binding proteins that bind to recognition sites located upstream of the core promoter. The chapter explains the mechanism of action of one of the most thoroughly characterized activators of σ70-dependent transcription in Escherichia coli, the cyclic AMP receptor protein (CRP), also known as the catabolite activator protein. A possible explanation for the change in the kinetics of λcI-dependent activation is discussed in the chapter. The chapter talks about activators that bind to DNA and affect the process of transcription initiation by making direct contacts with RNAP. The detailed structural basis for this activator induced promoter remodeling has recently been revealed by the crystal structure of the Bacillus subtilis BmrR protein, in complex with promoter DNA and a drug cofactor. In general, transcription activators that bind DNA and contact RNAP are thought to bind their specific DNA recognition sites and then, once appropriately positioned on the DNA, to interact with RNAP. The chapter discusses examples of activators that work only when bound to specific sites on the DNA, an activator that must be tethered to the DNA but remain mobile, and activators that can work directly from solution.
Performance and design considerations of the Farrow filter when used for arbitrary resampling of sampled time series

The Farrow filter structure enables arbitrary resampling of a time series by employing low order piecewise polynomials to approximate segments of the impulse response of a prototype low-pass filter from which samples of an arbitrary interpolator filter can be computed. Alternatively, the coefficients of the approximating polynomials can be applied directly to the input data to form, a data dependent, polynomial series expansion of the input data which can, in turn, be evaluated at the desired sample points.
A software development approach to implementing control systems specified through state analysis

The size and complexity of mission control software, both flight and ground, has increased rapidly over the last ten years. The fact that such software controls virtually all flight activities, and that failures attributed to software often have roots in systems engineering, has led to recognition of the need for a closer coupling between systems engineering and software engineering. Because of this, there has been an increasing amount of work devoted to developing new approaches to systems engineering for model-based control and operations system design. One such approach is state analysis. State analysis is a structured methodology for analysis of control problems that emphasizes state variables and behavior models. It strives to unify systems and software engineering disciplines into a common set of vocabulary, procedures, and tools, utilizing common framework software to achieve a very direct realization of analysis artifacts into code. This paper examines the practical application of state analysis by following the full development cycle of a prototype monitor and control system targeting NASA's proposed array-based deep space network (DSN), from initial state analysis through goal-based operations design, translation of systems engineering specifications into a software design, and finally implementation of the design through the adaptation of the software framework. The synergy between systems and software engineering is highlighted through concrete examples of reusable software design patterns that map directly to systems engineering artifacts, including mechanisms for goal-based fault tolerance. The paper also describes lessons learned from the application of the process and design patterns.
Application of Artificial Neural Networks to Medical Image Pattern Recognition: Detection of Clustered Microcalcifications on Mammograms and Lung Cancer on Chest Radiographs

Three neural network models were employed to evaluate their performances in the recognition of medical image patterns associated with lung cancer and breast cancer in radiography. The first method was a pattern match neural network. The second was a conventional backpropagation neural network. The third method was a backpropagation trained neocognitron in which the signal propagation is operated with the convolution calculation from one layer to the next. In the convolution neural network (CNN) experiment, several output association methods and trainer imposed driving functions in conjunction with the convolution neural network are proposed for general medical image pattern recognition. An unconventional method of applying rotation and shift invariance is also used to enhance the performance of the neural nets. We have tested these methods for the detection of microcalcifications on mammograms and lung nodules on chest radiographs. Pre-scan methods were previously described in our early publications. The artificial neural networks act as final detection classifiers to determine if a disease pattern is presented on the suspected image area. We found that the convolution neural network, which internally performs feature extraction and classification, achieves the best performance among the three neural network models. These results show that some processing associated with disease feature extraction is a necessary step before a classifier can make an accurate determination.
Effects of a single injection of cortisol on amino acid-incorporating activities of rat liver and thymic preparations in vitro.

Abstract Cell-free homogenates prepared from thymic tissue of rats injected 3 hours prior to sacrifice with cortisol, as compared with similar preparations from control rat thymus, show an impaired capacity to incorporate amino acids into microsomal or ribosomal protein, and a diminished ribonucleic acid polymerase activity. In contrast, cell-free preparations from liver tissue of the same steroid-treated rats reveal an increase in amino acid incorporation by microsomes or ribosomes. The levels of activities of the pH 5.0 activating enzymes, cathepsin, and acid RNase are not altered significantly in thymic tissue of rats as a consequence of the cortisol treatment. In both thymus and liver, the locus of action of the steroid on amino acid incorporation is reflected at the same subcellular level, the ribosomes. Although the injection of cortisol resulted in a decrease in RNA polymerase activity of thymic homogenates, no positive evidence was obtained in preliminary studies that there was a deficiency of messenger RNA on ribosomes prepared from cortisol-treated rats.
Field-focusing nuclear magnetic resonance (FONAR)

A technique, field-focusing NMR (FONAR), is described for doing NMR scans in large samples. The method utilizes a shaped D.C. magnetic field that confines the NMR-signal-producing region of the sample to a small volume called the resonance aperture. The aperture contains the required values of the H o field to fully bracket the band of the r.f. pulse. The magnet system and r.f. pick-up coil that achieved the first human NMR scan is discussed.
A Review of “Early Miocene Paleobiology in Patagonia. High-Latitude Paleocommunities of The Santa Cruz Formation”

Paleontologists must often rely on ‘Rosetta stones’—exceptionally preserved examples of ancient ecosystems—in order to make accurate interpretations of the ancient world. For researchers interested...
Study of P-type carbon doping on In 0.53 Ga 0.47 As, In 0.52 Al 0.2 Ga 0.28 As, and In 0.52 Al 0.48 As

The incorporation of carbon into In 0.53 Ga 0.47 As, In 0.52 Al 0.48 As and In 0.52 Al 0.2 Ga 0.28 As lattice matched to InP was investigated using carbon tetrabromide (CBr 4 ) as the carbon source in Metalorganic Chemical Vapor Depositions growth. The parameters and growth conditions are optimized to get high p-type doping for photonic device applications. This is among the first few studies on C-doping in InAlAs and InAlGaAs, and the results show that the presence of Al also efficiently helps to obtain high p-type carbon doping.
Discovering the pre-60S ribosome biogenesis factor interactome (560.7)

Maturation of the 60S ribosomal subunit is a highly coordinated and dynamic process that begins in the nucleolus and ends in the cytoplasm. Over 80 different proteins, including several helicases, ...
How does electronic cigarette access affect adolescent smoking

Understanding electronic cigarettes' effect on tobacco smoking is a central economic and policy issue. This paper examines the causal impact of e-cigarette access on conventional cigarette use by adolescents. Regression analyses consider how state bans on e-cigarette sales to minors influence smoking rates among 12 to 17 year olds. Such bans yield a statistically significant 0.9 percentage point increase in recent smoking in this age group, relative to states without such bans. Results are robust to multiple specifications as well as several falsification and placebo checks. This effect is both consistent with e-cigarette access reducing smoking among minors, and large: banning electronic cigarette sales to minors counteracts 70 percent of the downward pre-trend in teen cigarette smoking for a given two-year period.
Analytical methods for fitting integrated rate equations. A discontinuous assay.

The integrated rate equation for reactions with stoichiometry A----P + Q is: e0t = -Cf . ln(1-delta P/A0) + C1 delta P + 1/2C2(delta P)2 where the coefficients C are linear or quadratic functions of the kinetic constants and the initial substrate and product concentrations. I have used the 21 progress curves described in the accompanying paper [Cox & Boeker (1987) Biochem. J. 245, 59-65] to develop computer-based analytical and statistical techniques for extracting kinetic constants by fitting this equation. The coefficients C were calculated by an unweighted non-linear regression: first approximations were obtained from a multiple regression of t on delta P and were refined by the Gauss-Newton method. The procedure converged in six iterations or less. The bias in the coefficients C was estimated by four methods and did not appear to be significant. The residuals in the progress curves appear to be normally distributed and do not correlate with the amount of product produced. Variances for Cf, C1 and C2 were estimated by four resampling procedures, which gave essentially identical results, and by matrix inversion, which came close to the others. The reliability of C2 can also be estimated by using an analysis-of-variance method that does not require resampling. The final kinetic constants were calculated by standard multiple regression, weighting each coefficient according to its variance. The weighted residuals from this procedure were normally distributed.
Insulin and exercise differentially regulate PI3-kinase and glycogen synthase in human skeletal muscle

The purpose of this study was to determine the separate and combined effects of exercise and insulin on the activation of phosphatidylinositol 3-kinase (PI3-kinase) and glycogen synthase in human s...
Trade, factor mobility, and income distribution in a regional model with compensating wage differentials

Abstract This paper extends the basic theorems of international trade to a regional model where mobile factors of production consume non-traded goods in the region where they are employed. Factor mobility will not necessarily equate the wages of mobile factors across regions in this case, since wage differentials may be required in equilibrium to compensate for differences in prices of non goods. It is shown that the expenditure function for mobile factors can be used to obtain generalizations of the factor price equalization, Rybczynski, Heckscher-Ohlin and Stolper theorems which will be applicable to interregional trade.
Effects of aging on the suprathreshold responses to vibration

The psychophysical responses to vibration of two age groups (22 or 25 and 66 years) were compared for two tasks using suprathreshold levels of vibrotactile stimulation. At a vibration frequency of 25 Hz, the two age groups gave similar curves of subjective magnitude determined by the method of absolute magnitude estimation. At 250 Hz, the curve of the older group showed no recruitment over low levels of intensity. Instead, their magnitude estimates were depressed over the entire range of intensities. Sensory persistence, measured by a matching procedure, was more marked in the older group.
Enzyme-coated microelectrodes to monitor lactate production in a nanoliter microfluidic cell culture device

Monitoring the degree of anaerobic respiration of cells in high density microscale culture systems is an enabling key technology and essential for cell-based biosensors. We have fabricated and incorporated miniature amperometric lactate sensing electrodes with working areas from 3 to 5×10(-2) mm2 into a microfluidic-based microscale cell culture system to measure the lactate production rate of fibroblasts in nanoliter volumes. Planar thin film platinum electrode arrays on glass substrates were spin coated with lactate oxidase and a protective Nafion layer. The lactate electrodes had a high enzymatic activity described by a Michaelis-Menten constant of 2.6±0.1 mM, a linear response in the range 0.01-2.5 mM and a sensitivity of 7.3×10(-2) mA/mM cm2. A replica-molded polydimethylsiloxane (PDMS) microfluidic device with nanoliter sensing volumes was aligned and sealed to a glass substrate with the sensing electrodes. We trapped fibroblasts in the cell culture volume and measured the lactate production rate using a stop-flow protocol. The average lactate production rate was 0.011±0.0049 mM/min. The lactate production was suppressed with the addition of 2-deoxy-D-glucose, which binds to hexokinase. The blocking of hexokinase prevents the generation of pyruvate, the intermittent substrate required for lactate production even in the presence of glucose.
Application of X-Ray Computed Tomography to Ceramic/Ceramic Composites

A computed tomographic imaging system has been given an initial evaluation for the ability to detect voids and characterize fiber orientation in ceramic composites consisting of SiC fibers in a matrix of chemical vapor infiltrated SiC. Specimens with various fiber loadings and different final densities, fabricated from random chopped fibers, continuous unidirectional fibers, and layups of various cloth types were examined. Specimens in various early stages of processing were also examined to see if the presence of a graphite fixture (used in the CVI process) caused image degradation. The results show that the CT images are able to discriminate among fabric weaves and show major fabric-weave characteristics prior to SiC impregnation, after impregnation to at least 85% of theoretical density, and in the presence of a graphite holder. However, with the currently available 100 μm pixel size and implementation of zoom features, individual voids on the order of 200 μm cannot be detected.
Alzheimer’s Disease Research: A Game of Connect the Dots

Although a vast number of experimental investigations have focused on various aspects of Alzheimer’s disease (AD), the pathogenic mechanism of the disease has not been established. AD research is a dynamically changing field that has entertained a variety of hypotheses. Since most of the data pertaining to AD pathogenesis is obtained in postmortem tissue or in vitro experiments, researchers must play a game of ‘connect the dots’ to try to correlate the diverse aspects of the disease and generate hypotheses regarding the sequence of pathological events. This article reviews the current state of AD research, and presents three hypothetical models for disease progression.
A flow injection (FI) biosensor system for pentachlorophenol (PCP) using a substrate recycling scheme.

A flow injection (FI) biosensor system has been designed for the analysis of pentachlorophenol (PCP) using a substrate recycling scheme comprising immobilized bilirubin oxidase (BOX) in the presenc...
Ischemic postconditioning protects against focal cerebral ischemia by inhibiting brain inflammation while attenuating peripheral lymphopenia in mice

Background Ischemic postconditioning (IPostC) has been shown to attenuate brain injury in rat stroke models, but a mouse model has not been reported. This study establishes an IPostC model in mice and investigates how IPostC affects infiltration of leukocytes in the ischemic brain and lymphopenia associated with stroke-induced immunodepression.
Diagnosis of autoimmune skin disease in the dog: Correlation between histopathologic, direct immunofluorescent and clinical findings

Histopathologic, immunopathologic and clinical evaluation of two hundred thirty dogs resulted in a diagnosis of canine autoimmune skin disease (AISD) in eighty four of the suspected cases. Pemphigus foliaceus was the most common diagnosis, followed by bullous pemphigoid and pemphigus vulgaris. The highest percentage of cases were mixed breeds, followed by shelties, collies, German shepherds and poodles. There was no apparent age or sex predilection. Eighty seven percent of the eighty four cases of AISD were diagnosed on the basis of supportive clinical criteria in addition to compatible histopathologic and/or direct immunofluorescent findings. Thirteen percent of the cases with a final clinical diagnosis of AISD lacked supportive immunohistopathologic criteria on biopsy and the diagnosis was based upon clinical appearance, exclusion of other dermatoses, and response to immunosuppressive therapy. This latter group included four cases of SLE diagnosed using a combination of clinical criteria and a positive test for antinuclear antibody. Thirty three percent of the AISD cases were diagnosed on the basis of compatible findings on both histopathology and direct immunofluorescence. A histopathologic diagnosis of AISD was made in sixty nine percent of the cases. Positive direct immunofluorescence was found in fifty two percent of the cases. Thirty five percent of the AISD cases were diagnosed on histopathologic criteria without supportive immunofluorescent findings, while nineteen percent had positive direct immunofluorescence with nonspecific histopathologic changes. The number of definitive positive results was greater for direct immunofluorescence (38%) than for histopathology (25%). There was an equal incidence (21%) of false positive results among non-AISD cases with both tests. Indirect immunofluorescence appears to have little value in the diagnosis of canine AISD. The recommended diagnostic approach to canine AISD involves the use of both histopathologic and immunopathologic evaluations.
Influence of Large Metal Cations on the Photophysical Properties of Texaphyrin, a Rigid Aromatic Chromophore

The excited-state properties, including singlet oxygen quantum yields, of a series of metallotexaphyrins (M-Tex), containing coordinated paramagnetic and also diamagnetic lanthanide(III) and other cations, are reported as are the solution-phase magnetic susceptibilities of the paramagnetic species. It is found that the singlet (1.593−1.638 eV) and triplet excited-state (1.478−1.498 eV) energies are only marginally affected by the choice of coordinated metal species. By contrast, photophysical parameters that are directly associated with the intrinsic decay rates of, for example, the singlet excited state, such as fluorescence lifetimes, reveal a strong dependence on the nature of the coordinated metal species. In particular, for the series of diamagnetic metals including Y−Tex, In−Tex, Lu-Tex, and Cd−Tex, an increase in atomic number leads to notably shorter lifetimes (τfluorescence(Y-Tex) = 1298 ps, τfluorescence(Lu-Tex) = 414 ps), a result that is interpreted as a heavy atom effect. The paramagnetic spe...
View factors for wall to Random dispersed solid bed transport

Radiant heat transfer in fluidized beds (Brewster 1986; Grace, 1982) or dispersed solid insulation involves energy exchange between a well-defined wall surface and a random bed of solid particles whose geometry is known only in a statistical sense. In instances where the walls and bed can be considered gray-diffuse surfaces, the temperatures of each are nearly uniform, and particle dimensions (Grace, 1982) are much larger than the thermal radiation wavelength, the view factor and straight-forward (Siegel and Howell, 1981) net-radiation methods can be applied to calculate radiant heat transport rates. Beyond radiation, the wall-to-random bed view factors have additional applications where the characteristic dimensions of the dispersed solid need not be large. Barron (1985) has pointed out that view factors can be used in low-pressure cryogenic insulation for Knudsen void gas heat transfer. Wall-to-bed view factors will also predict mass transfer deposition rates into random fibrous or particulate supports, for low-pressure sputtering processes (Wehner and Anderson, 1970). Wall-to-bed view factors are calculated and plotted versus bed void fraction and thickness for several model dispersed solids - overlapping, equisized spheres and overlapping, identical, parallel long cylinders (parallel both to the wall and to each other) - randomly placed in the volumemore » between two infinite parallel planes.« less
Regulation of IFN‐γ production in granulocyte‐macrophage colony‐stimulating factor‐deficient mice

++ T cells from LPS-injected GM-CSFn/n mice showed a deficiency in IFN- production and proliferative activity in response to IL-2 and IL-12, whereas IFN- production by NK cells was not compromised. These defects of T cells were reversed by administration of GM-CSF in vivo, but not by supplementation with GM-CSF in vitro. GM-CSFn/n mice do not have an intrinsic defect in IFN- production, because IL-12 injection induces the same high levels of IFN- in GM-CSFn/n and GM-CSF+/+ mice. To investigate the inhibitory effect of LPS on GM-CSFn/n T cells and the indirect restorative activity of GM-CSF, we tested the action of supernatants from cultured dendritic cells (DC). A factor or factors in the DC supernatant normalized serum IFN- levels and T cell responses in LPS-injected GM-CSFn/n mice. IL-18 reproduced some but not all of these in vivo and in vitro effects of DC supernatants. Our results indicate that GM-CSF is important in protecting T cells from inhibitory signals generated during immunization or exposure to LPS, and that this effect of GM-CSF is indirect and mediated by factors produced by DC.
Homographic entries in the internal lexicon

The task was to distinguish between English and nonsense words, which were displayed singly. The display persisted until S pressed the yes -key if he thought the stimulus was English or the no -key if he thought it was nonsense. The response times were faster for English than nonsense, faster for English words of higher frequency than lower frequency, and faster for homographs than nonhomographs. It is hypothesized that word recognition in general requires consulting the internal lexicon. A model of the underlying processes is sketched which proposes that words of higher frequency are recognized sooner because their lexical entries are marked earlier for comparison against the stimulus information. It is also proposed that homographs are recognized sooner than nonhomographs since homographs have more lexical entries available for comparison against the stimulus information.
The preparation of crystalline hydroxylamine satisfactory for amino acid activation studies.

Abstract The preparation of crystalline hydroxylamine from the hydrochloride in 50% yield has been described. Using this hydroxylamine to study proline activation in a preparation from guinea pig liver, optimum concentrations of hydroxylamine, proline, and hydrogen ion were determined.
Propyl 1,4-Benzodioxan-2-carboxylate, A New Attractant for the European Chafer

Of 340 chemicals tested as attractants against Amphi mallon majalis (Razoumowsky), the most effective compounds were esters of 1,4-benzodioxan-2-carboxylic acid. The attraction of 5 of these esters ranged from 1.5 to 2.9 times that of butyl sorbate, the lure that is presently being used. The best of the 5 was the propyl ester, for which the name amlure is proposed. Amlure is much longer lasting and more stable than butyl sorbate.
NCBI BLASTP on the convey HC1-EX

The BLAST sequence alignment program is a central application in bioinformatics. The de facto standard version, NCBI BLAST, uses complex heuristics which make it challenging to simultaneously achieve both high performance and exact agreement. In previous work, a system that used novel FPGA-based filters reduced the input database by over 99.97% without loss of sensitivity. In the present work we report experiences in getting from a prototype to a potential product for the Convey HC1-EX. There are several issues. The first is the efforts made to maintain timing for a highly complex configuration as it is optimized by including additional filter stages. This requires implementation and optimization of new interface logic as well as floor-planning. The second is the system-level tradeoffs necessary to maintain correctness. The issue here is preventing low frequency events, which necessarily cannot be mapped to the FPGA, from diluting the performance benefits without sacrificing sensitivity. We present results for various usage scenarios and find a factor of nearly 5x speed-up over a fully parallel implementation of the reference code on a contemporaneous CPU. We believe that the resulting system is the leading accelerated NCBI BLAST. The significance of this work is that, while such in-depth work is necessary to achieve highperformance for complex systems, these issues are rarely described nin the academic literature.
Teaching Undergraduates about Teaching Undergraduates: A Capstone Course:

In this article, we describe a senior-level capstone course on the profession of college teaching. Taught in a seminar fashion, the course required students to discuss various issues associated with college teaching (e.g., lecturing, grading, and cultural diversity), which were introduced through various outside readings, and to engage in some form of “teaching experience” during the semester (e.g., tutoring or presenting a minilecture). In addition, students observed faculty members1 lectures. We sought to combine the goal of providing undergraduates a capstone experience with the goal of attracting our better students to the teaching profession. The course also provided an unanticipated vehicle for obtaining important feedback about the way we teach undergraduates in our department and for aiding faculty development in the area of teaching.
Regulation of human megakaryocytopoiesis.

Megakaryocytopoiesis is a complex biological process involving a series of cellular events that begins with the pluripotent hematopoietic stem cell and ultimately results in the biogenesis of platelets1. A hierarchy of MK progenitor cells, the progeny of which eventually proliferate and mature into MKs, has been defined1–3.
Theory of Enhance I Light Scattering from Molecules Adsorbed at the Metal-Solution Interface

We present a theory to explain the anomalous enhancement of light scattering from molecules adsorbed at a metal-solution interface. It is found that tunneling of electrons between a surface molecule and the metal induces a resonance at a point in the vicinity of the Fermi surface. A dynamical equilibrium due to photoionization and recombination stabilizes the system near resonance.
New perturbation results for solving the linear complementarity problem with Po-matrices☆

Abstract We provide new conditions under which the linear complementarity problem (LCP) can be solved by a perturbation method when the associated matrix is a P o -matrix. The new conditions apply to both degenerate and nondegenerate LCPs. Moreover, these conditions do not require that the P o -matrix belong to another matrix class such as, for example, the R o -matrix class.
Validation of the Perceptions of Teasing Scale (POTS) in a Preadolescent Sample: Associations With Attitudes Toward Physical Activity

This study investigated the construct validity of the Perceptions of Teasing Scale (POTS) in a sample of 381 preadolescent children (mean age = 10.8 years). Children completed the POTS and self-report measures of attitudes toward physical activity (PA). Anthropometric data were collected as a part of a standard school health assessment. Confirmatory factor analysis and structural equation modeling supported the validity of the POTS. Children who experienced more teasing about abilities and competency reported increased negative attitudes and fewer positive attitudes toward PA. Children who reported more appearance-related teasing endorsed more negative attitudes about PA. Results indicate that the POTS is a valid measure of teasing among preadolescent children and that teasing may be an important target for prevention and intervention efforts to increase PA among children.
Frequency and distribution of edge damage on Middle Stone Age lithic points, Pinnacle Point 13B, South Africa

Unretouched convergent flakes are frequently a well represented tool type in many Middle Stone Age (MSA) assemblages. Damage to the lateral margins of these points is frequent; however, analytical methods for dealing with the frequency and distribution of edge damage on points have not been developed and applied to a complete MSA lithic assemblage. A method for using GIS to quantify edge damage and statistically analyze the relative location and frequency of edge damage is presented here and applied to the complete assemblage of MSA points from Pinnacle Point Cave 13B (PP13B), South Africa. The results indicate a frequency of edge damage consistent with heavier utilization of the dorsal surface over the ventral surface, and the left side over the right, with the dorsal left lateral margin being most heavily damaged. Additionally, the distribution of edge damage and low frequency of impact damage to the points suggest that PP13B represents a location where points were used for cutting activities and discarded. Applying the recording procedures advocated here to controlled edge damage replication experiments will help provide the interpretive linkages to site assemblage edge damage distributions.
Changing excitation and inhibition in simulated neural networks: effects on induced bursting behavior.

The development of synchronous bursting in neuronal ensembles represents an important change in network behavior. To determine the influences on development of such synchronous bursting behavior we study the dynamics of small networks of sparsely connected excitatory and inhibitory neurons using numerical simulations. The synchronized bursting activities in networks evoked by background spikes are investigated. Specifically, patterns of bursting activity are examined when the balance between excitation and inhibition on neuronal inputs is varied and the fraction of inhibitory neurons in the network is changed. For quantitative comparison of bursting activities in networks, measures of the degree of synchrony are used. We demonstrate how changes in the strength of excitation on inputs of neurons can be compensated by changes in the strength of inhibition without changing the degree of synchrony in the network. The effects of changing several network parameters on the network activity are analyzed and discussed. These changes may underlie the transition of network activity from normal to potentially pathologic (e.g., epileptic) states.
CD70+ non-Hodgkin lymphoma B cells induce Foxp3 expression and regulatory function in intratumoral CD4+CD25 T cells.

Foxp3 expression was initially thought to be restricted to the CD4+CD25+ regulatory T-cell population. However, recent studies suggest that forkhead box P3 (Foxp3) is expressed in CD4+CD25− T cells in aged mice. In the present study in B-cell non-Hodgkin lymphoma (NHL), we found that a subset of intratumoral but not peripheral blood CD4+CD25− T cells, comprising about 15% of intratumoral CD4+ T cells, express Foxp3 and are capable of suppressing the proliferation of autologous infiltrating CD8+ T cells. In vitro activation with OKT3/anti-CD28 antibody (Ab) or dendritic cells (DCs) induced Foxp3 expression in a subset of these CD4+CD25−Foxp3− T cells. We found that the presence of lymphoma B cells during activation augmented activation-induced Foxp3 expression in CD4+CD25− T cells. We also found that CD70+ lymphoma B cells significantly contributed to the activation-induced Foxp3 expression in intratumoral CD4+CD25− T cells. Furthermore, the blockade of CD27-CD70 interaction by anti-CD70 Ab abrogated lymphoma B-cell–mediated induction of Foxp3 expression in intratumoral CD4+CD25− T cells. Taken together, these studies reveal a novel role for NHL B cells in the development of intratumoral regulatory T cells.
Parent-Collected Behavioral Observations: An Empirical Comparison of Methods

Treatments for disruptive behaviors are often guided by parent reports on questionnaires, rather than by multiple methods of assessment. Professional observations and clinic analogs exist to complement questionnaires, but parents can also collect useful behavioral observations to inform and guide treatment. Two parent observation methods of child aggression and noncompliance were compared: the Parent Daily Report (PDR) and Behavior Record Cards (BRC). Parents tracked misbehavior for 2 weeks using the PDR or BRC. BRC data proved to be more accurate, though both systems yielded strong reliability and moderate validity. The BRC is recommended to clinicians on empirical and conceptual grounds.
1029 EXPRESSION OF CELL MEDIATED IMMUNITY TO INFLUENZA IN BREAST FED INFANTS

The suggestion of fewer viral infections in breast fed infants has raised the possibility of a role for colostral lymphocytes (COL) in the transfer of viral cell mediated immunity (CMI) via breast feeding. In vitro lymphocyte stimulation (LT) assay with influenza antigens was used to assess CMI. We studied 14 healthy mother-infant pairs 1-6 days after delivery and 8 pairs were followed up 1-4 months later. Peripheral blood lymphocytes (PBL) and COL were tested for LT using ether extracted influenza antigens (A/Tex, A/Brazil, and B/Hong Kong). Lymphocyte responsiveness to PHA was confirmed. A pos. influenza response was defined as a stimulation ratio ≥2.0. After delivery 12/14 PBL from mothers and 5/13 COL were pos. to one or more influenza antigens; at follow-up 8/8 maternal PBL were pos. After delivery 7/14 infant PBL were pos. and of 8 infants not yet breast fed, 5 were pos. At follow-up 3/8 infants were pos., all 3 of whom had been negative after delivery. No respiratory infections were recognized in any of the study infants. CMI to influenza was demonstrated in many maternal PBL and COL samples after delivery and in all PBL at follow-up. While 3 infants acquired CMI to influenza after breast feeding, 5 infants had CMI after delivery and prior to breast feeding. These studies suggest that breast feeding may confer CMI to the infant but also imply that another maternal mechanism for an earlier acquisition of CMI exists.
Infrared Optical Properties of Single Crystals of Tellurium

The fundamental optical absorption and photoconductivity of single crystals of tellurium has been investigated. Tellurium crystals exhibit dichroism in the infrared, i.e., the absorption constant depends on the polarization of the incident radiation. At 300\ifmmode^\circ\else\textdegree\fi{}K for radiation polarized perpendicular to the $C$ axis the absorption edge, located by means of an arbitrary criterion, is at 3.82 microns (0.324 ev); for the case of polarization parallel to the $C$ axis the same criterion locates the second edge at 3.29 microns (0.374 ev). The difference between absorption constants survives at wavelengths beyond the edges and is ascribable to the effective masses of the carriers, which depend on their direction of motion relative to the crystal axis. The variation of the energy gaps with temperature has been observed to be -2\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}5}$ ev/\ifmmode^\circ\else\textdegree\fi{}C, i.e., the energy gaps decrease with increasing temperature. Comparison is made with existing theories. The photoconductivity which is barely detectable at room temperature is considerably enhanced by a reduction of the temperature to 90\ifmmode^\circ\else\textdegree\fi{}K. The spectral response indicates the presence of two peaks corresponding in position to the absorption edges. Measurements of the dependence of photoresponse on voltage, light intensity, and shuttering speed indicate that the photoresponse is at least partially in conformity with a monomolecular model. Selenium-tellurium alloys containing 2.7 percent and 11 percent selenium by weight and therefore possessing a considerably reduced lattice volume show a shift of photoconductivity and transmission toward shorter wavelengths, i.e., larger energy gaps.
Farmer support for publicly funded sustainable agriculture research: The case of hoop structures for swine

Environmental and social concerns about the use of capital-intensive agricultural technologies have fueled questions about the process, impact, and future direction of the system that is largely responsible for developing these technologies; that is, publicly funded agricultural research at U.S. land-grant universities. Although social scientists have analyzed the public agricultural research system and farmers' attitudes towards various capital-intensive agricultural technologies, there has been less research on farmers' attitudes toward publicly funded research that focuses specifically on lowerinput agricultural technologies that contribute to sustainability goals. This research examines farmers' attitudes toward publicly funded research on one such low-input technology, deep-bedded hoop structures for swine production. With lower capital costs and purported environmental and management advantages, hoop structures have been promoted to and adopted by growing numbers of Midwest swine producers. The study hypotheses draw on published theories of the treadmill of technology, and of innovation adoption and diffusion. Using a 1997 mail survey of Iowa swine producers (n = 298), we examined factors associated with producers' attitudes toward publicly funded research on hoop structures and found that 40% were supportive of the research, 40% were opposed, and 20% were undecided. Of the variables examined, the producer's assessment of hoop structures' contribution to sustainability, number of external knowledge sources about hoop structures, and formal education were each significantly related to support for publicly funded hoop-structure research. Two farm structure variables, marketings and percentage of income from farming, were not significantly related in this study. Future research on farmers' attitudes toward public sector agricultural research should take account of farmers' views of potential impacts of the specific technologies being researched and developed, and the nature of farmers' ties to the land-grant university system. This study clarifies the importance of farmers' perceptions and concerns about specific agricultural technologies in directing public agricultural research planning and policy toward broader sustainability goals.
Recombination Dynamics In Microstructures

Recombination dynamics in 111-V quantum well structures have been investigated using a wide variety of optical techniques. Results of these studies have a number of implications for the design of light-emitting devices.
Chemical Genetic Blockade of Transformation Reveals Dependence on Aberrant Oncogenic Signaling

Abstract Background: Our understanding of protein kinase inhibition in the treatment of cancer is clearly limited by the lack of inhibitors that selectively block a single kinase implicated in neoplastic transformation. One approach to developing specific inhibitors is to engineer in protein kinases silent mutations that allow selective inhibition while retaining kinase activity. Because it is implicated in a large number of malignancies, EGFR provides an attractive target for such selective kinase inhibition. Results: We generated an inhibitor-sensitized allele of the transforming receptor tyrosine kinase v-erbB . Transformation of immortalized rodent fibroblasts by sensitized versions of v-erbB ( v-erbB-as1 ) was blocked by 1-napthyl PP1 (NaPP1), a cell-permeable ATP-competitive inhibitor. NaPP1 also reversed morphological transformation by v-erbB-as1 . Signaling through MAP kinase and PI(3) kinase was initially blocked by inhibitor treatment and then recovered to levels comparable to those in nontransformed cells. Surprisingly, NaPP1-treated v-erbB-as1 cells failed to re-enter the cell cycle, showed decreased levels of D- and A-type cyclins, and showed increased levels of p27. To extend this result, we showed that NaPP1 treatment of v-Src -as1 cells also led to cell cycle arrest. Arrested cells could be rescued with a conditional allele of Raf or by transduction of a constitutive allele of cyclin D1. Conclusions: These data suggest that mammalian cells can become dependent on aberrant oncogenic signaling; this dependency renders them incapable of returning to a normal, proliferative phenotype.
Reflexive and Volitional Saccades: Biomarkers of Huntington Disease Severity and Progression

Huntington disease (HD) is a genetic, neurodegenerative disorder characterized by chorea, behavioral co-morbidities, cognitive deficits, and eye movement abnormalities. The earliest documented cell loss in HD patients occurs in the basal ganglia, particularly in the striatal medium spiny neurons and the external segment of the global pallidus (1, 2). Eventually, degeneration is widespread and includes the brainstem (1, 3). Eye movements critically depend on the coordinated functioning of the brainstem, thalamus, basal ganglia, and cortex. All these structures are affected in HD and it is, therefore, not surprising that multiple eye movement deficits exist in patients with HD (4–22). As a result of recent research focusing on further discriminating types of saccadic eye movements, two parallel systems have been proposed that differentially govern reflexive and volitional saccades (23–25). Frontal structures and the basal ganglia play a key role in both voluntary saccades and control (tonic inhibition) of reflexive saccades. In addition, both systems share common motor brainstem output nuclei. Thus, specific lesions will differentially impair the two types of saccades. More importantly, specific changes in saccade performance will provide a basis to infer specific neuropathological changes in HD. Eye movement deficits, particularly in voluntary saccades (4, 8, 12, 16, 20, 21, 26, 27) and in fixation maintenance (8, 10, 12), have been well documented in HD patients, even in early stages. Some studies have shown that even presymptomatic HD patients have voluntary saccade deficits (21, 22, 28–30). The performance of reflexive saccades in HD patients is less consistent, with some studies finding slowing (4, 5, 7, 11–15) and others reporting them as intact (20–22). The saccadic slowing affecting both reflexive and voluntary saccades, is usually attributed to the development of brainstem dysfunction (12, 16, 17, 25). Despite numerous eye movement studies in HD, only a few have correlated eye movement parameters with HD severity as measured by the Unified Huntington Disease Rating Scale (UHDRS) motor subscale to determine their usefulness as a biomarker for disease severity and progression(4). Moreover, the only previous study (4) we are aware of that established any correlation between eye movement parameters and the UHDRS did not take into account age. Age is known to affect reflexive and voluntary eye movements (31). Establishment of simple, non-invasive and age-controlled biomarkers of motor and cognitive disease severity is important for monitoring progression, preclinical diagnosis, differentiating subtypes, and development and evaluation of treatments (32). Eye movement deficits, themselves, are also associated with increased risk of developing HD (13, 33).
New Measurement of the Cosmic-Ray Positron Fraction from 5 to 15 GeV

We present a new measurement of the cosmic-ray positron fraction at energies between $5$ and 15 GeV with the balloon-borne HEAT-pbar instrument in the spring of 2000. The data presented here are compatible with our previous measurements, obtained with a different instrument. The combined data from the three HEAT flights indicate a small positron flux of nonstandard origin above 5 GeV. We compare the new measurement with earlier data obtained with the HEAT-${e}^{\ifmmode\pm\else\textpm\fi{}}$ instrument, during the opposite epoch of the solar cycle, and conclude that our measurements do not support predictions of charge sign dependent solar modulation of the positron abundance at 5 GeV.
Isolation and crystal structure of an unusual ditelluride: bis(N,N-dimethylaminoformyl) ditelluride

Abstract Solutions of disodium ditelluride in N,N-dimethylformamide (DMF) react with the solvent to give small yields of the unsual ditelluride, [Me2NC(O)]2Te2. This molecule, which exhibits interesting photochemical behavior has been characterized and its crystal structure has been determined.
The solubility of the mineral phase in the rat of powdered bone and dentine laden with strontium.

Abstract Dry, fat-free powdered bone and incisor dentine obtained from animals grown on diets containing known amounts of calcium, strontium and phosphorus were investigated. Repeated extraction of the powders with an ethanolic-hydrochloric acid solution was performed and the leachings from each repetition were analyzed for calcium, phosphorus and, in high strontium powders only, strontium. Analyses revealed that high-strontium bone contained less ash than low-strontium bone, but the two kinds of dentine had virtually identical ash contents. The interpretation of the Ca Sr and (Ca + Sr) P molar ratios is that strontium was not preferentially removed from either high-strontium bone or high-strontium dentine, and therefore, strontium was not predominantly surface-located. Bone appears to be much more susceptible to alteration in vivo by a high concentration of dietary strontium than does dentine.
Toxicity and estimated water quality criteria values in mallard ducklings exposed to pentachlorophenol

Tests were conducted to determine the effects of pentachlorophenol (PCP) in feed on growth and bioaccumulation in mallard ducklings (Anas platyrhynchos). Significant effects of PCP on growth (LOAEL) were observed after 11 days at 961 μg/g PCP. The NOAEL value (no significant growth effects) was 423 μg/g PCP. Concentrations of PCP in tissues at the NOAEL were 20.7 (liver), 12.2 (lipid), 3.3 (muscle), and 2.6 (brain) μg/g (wet wt); no bioaccumulation was observed. Using a toxicity threshold model, it was estimated that about 1.1 mg/L of waterborne PCP was a threshold for adverse effects for mallard ducks.
Network Analyzer Accuracy Overview

Calibration and error-correction technology is fundamental to accurate network analyzer measurements. This paper will discuss the sources of errors in a network analyzer and which errors can be reduced by the calibration, which errors can not be removed and which errors are increased by the error-correction process. The residual errors that remain after the calibration can then be quantified so that an error-corrected measurement accuracy can be determined. This paper will then summarize a process that can be used to determine sound and traceable specifications for a network analyzer and the tradeoffs between various calibration methods.
Short communication: Effects of heat treatments and CdCl2, pretreatments on the stoichiometries of solution-grown CdS thin films

Solution grorwth of CdS on SnO2-coated glass with subsequent heat treatments is known to produce stoichiometric CdS thin films with characteristic thicknesses of about 1000 A. We show that heating solution-grown CdS thin films in a nitrogen atmosphere to ⩾ 450° C results in sulphur loss. Heating to 550°C leads to a 50% loss of sulphur, leaving the entire 1000-A CdS thin film with a concentration of about 75 at.% Cd and 25 at.% S. However, dipping the CdS thin films in a CdCl2 solution prior to heating coats the CdS, leaving a CdCl2 layer that acts as a protective coating and prohibits the loss of sulphur. Cadmium sulphide thin films dipped in a CdCl2 solution and then heated to 550°C are stoichiometric.