cssi/SciSciGPT-SciSciNet huggingface dataset:
Thermal Characterization of Defects in Aircraft Structures Via Spatially Controlled Heat Application

Recent advances in thermal imaging technology have spawed a number of new thermal NDE techniques that provide quantitative information about flaws in aircraft structures. Thermography has a number of advantages as an inspection technique. It is a totally noncontacting, nondestructive, imaging technology capable of inspecting a large area in a matter of a few seconds. The development of fast, inexpensive image processors have aided in the attractiveness of thermography as an NDE technique. These image processors have increased the signal to noise ratio of thermography and facilitated significant advances in post-processing. The resulting digital images enable archival records for comparison with later inspections thus providing a means of monitoring the evolution of damage in a particular structure. The National Aeronautics and Space Administration''s Langley Research Center has developed a thermal NDE technique designed to image a number of potential flaws in aircraft structures. The technique involves injecting a small, spatially controlled heat flux into the outer surface of an aircraft. Images of fatigue cracking, bond integrity and material loss due to corrosion are generated from measurements of the induced surface temperature variations. This paper will present a discussion of the development of the thermal imaging system as well as the techniques used to analyze the resulting thermal images. Spatial tailoring of the heat coupled with the analysis techniques represent a significant improvement in the delectability of flaws over conventional thermal imaging. Results of laboratory experiments of fabricated crack, disbond and material loss samples will be presented to demonstrate the capabilities of the technique. An integral part of the development of this technology is the use of analytic and computational modeling. The experimental results will be compared with these models to demonstrate the utility of such an approach.
Combination Therapy for Invasive Mycoses: Evaluation of Past Clinical Trial Designs

Background Despite the availability of new antifungals, single-agent therapy frequently falls short of high cure rates. Combination therapy offers potentially higher cure rates, especially for resistant organisms. In vitro studies and experimental animal models have provided conflicting data. Methods Retrospective, randomized, controlled clinical studies were reviewed. Results Results indicate a clear advantage for polyene and flucytosine combination therapy in cryptococcal meningitis and a possible advantage for combination amphotericin B and fluconazole for candidemia. Unfortunately, the few studies published have been flawed by design problems that have compromised the determination of outcome. Study review allows investigators the opportunity to design future studies to ensure optimal evaluation of efficacy. Conclusion Combination antifungal therapy is advantageous in cryptococcal diseases and may have a role in the treatment of invasive candidiasis. The greatest potential exists for combination therapy against aspergillosis and resistant fungi in patients with refractory mycotic disease who experience failure of monotherapy.
Interest in medical therapy for celiac disease.

Objectives:A gluten-free diet is the treatment for celiac disease, but pharmaceutical agents are being developed. The level of interest amongst patients in using a medication to treat celiac disease is unknown. This study examined the level of interest amongst patients in medication to treat celiac disease.Methods:A questionnaire was distributed to celiac disease patients and data were collected on demographics, presentation, and interest in medication. Three validated celiac disease-specific instruments were incorporated: Celiac Disease Associated Quality of Life, the Celiac Symptom Index, and the Celiac Dietary Adherence Test.Results:Responses were received from 365 individuals with biopsy-proven celiac disease. Respondents were 78% (n = 276) female, 48% (n = 170) over 50 years of age, and experienced a classical (diarrhea predominant) presentation in 44% (n = 154). Of the 339 individuals answering the question regarding use of a medication to treat celiac disease, 66% were interested. Interest was grea...
Blackface Minstrelsy in Britain

Blackface Minstrelsy in Britain MICHAEL PICKERING Burlington, VT: Ashgate, 2008 ISBN 978‐0‐7546‐5859‐7 253 pp., $99.95 Michael Pickering contributes to the growing scholarship on blackface minstrel...
Decentralizing Library Web Content Responsibilities Using Dynamic Web Pages

ABSTRACT Maintaining and updating the library Web site consumes a significant amount of resources in any library. But tools exist to help decentralize the process of publishing content to the Web. The implementation of dynamic Web pages enables professionals with little or no experience in Web editing to maintain and update Web content, leaving the design and development of these pages to those better qualified. The use of dynamic Web pages allows a more efficient, productive workflow to develop by enabling those closest to the content to create and update the pages.
Optimal performance of pneumatic transport systems

In order to improve the operation of pneumatic transport systems, we developed two techniques that can be employed on existing systems to increase their efficiency. These techniques can be applied on-line to a system striving toward optimal performance. As an application of the technique, a 0.10-m diameter conveying line transporting 1 mm polyester particles over a 30-m distance was employed. The first approach to optimal performance uses either constant inlet pressure conditions or constant solids throughput. The iso-pressure drop method is performed by operating this system at two state parameters at a constant pressure while the constant solids throughput employs a similar procedure. The two state parameters are pressure drop and either the gas mass flow rate or solids rate. By individual changes in these parameters, one can explore small variations around an operating point and develop an approximation to the derivative of the parameter. Extrapolation of the information to the optimal condition can be carried out pursuing the point where the derivative goes to zero. Expanding the data set refines the operation and produces a more exact optimal condition. The second approach to optimal performance utilizes a neural network description of the conveying phase diagram. Once the description is defined, optimization procedures can be applied to hone in on the optimal operating point. This procedure involves training the neural network, which sometimes requires a large database for accuracy. The present application shows the speed with which the network can be trained.
Gigabit LAN issues - HIPPI, fibre channel, or ATM?

Computer networks that operate in the gigabit per second speed range are becoming very important for interconnecting supercomputers, clusters of workstations, and other high end equipment. HIPPI is the current interface of choice, while Fibre Channel and ATM are emerging standards. These systems are examined as to their backgrounds, advantages, and shortcomings.
Population screening for glucose intolerant subjects using decision tree analyses

The purpose of this study was to develop a method of screening for impaired glucose tolerance and previously undiagnosed NIDDM that could be used preliminary to the administration of an oral glucose tolerance test (OGTT) for final classification of glucose tolerance status. The purpose of a preliminary screening of this type would be to reduce the number of OGTT's needed to identify cases of IGT and NIDDM in the population. We used NIDDM risk indicators and decision tree analysis methods (CART software) to identify subgroups of the population at increased risk. We examined a population of Hispanic (n = 583) and non-Hispanic white (n = 768) subjects without a prior history of diabetes. Subjects were classified as normal, IGT or NIDDM (WHO criteria) based on results from a 75 g oral glucose tolerance test (OGTT). Sensitivity (SEN) and specificity (SPE) of the CART models were calculated using the OGTT as the 'gold standard.' Two approaches to screening were simulated. In the simultaneous approach all risk variables were entered into CART models at once. In the serial approach, risk variables were grouped according to degree of effort required for data collection, and were entered into CART models in stages. Fasting glucose, age and body mass index (BMI) were selected as risk variables by CART when simulating the simultaneous approach (SEN = 91%, SPE = 55%). In the serial approach, CART used age and BMI to eliminate 35% of the population from further screening, and then used fasting glucose, glycohemoglobin, age and BMI to classify the remaining higher risk subjects (SEN = 85%, SPE = 64%). These models suggest that screening for IGT and previously undiagnosed NIDDM can be based on measurement of relatively simple indicators, and yet maintain a level of both sensitivity and specificity acceptable for this type of preliminary screening.
Prolyl endopeptidase purified from granulomatous inflammation in mice.

Activity of prolyl endopeptidase (EC 3.4.21.26) which hydrolyses the Pro7-Phe8 bond in angiotensin II has been found to elevate in experimentally produced granulomatous inflammation in liver and skin. We purified the enzyme 1,536-fold by 6 steps from murine hepatic granulomas. The purified enzyme has a molecular weight of 79 kDa and physiocochemical properties equivalent to those previously reported for prolyl endopeptidase purified from other sources. By HPLC analysis, the cleavage of Phe8-Leu10 and Phe8 from angiotensin I and II, respectively, was detected and quantified. Monospecific IgG was prepared from serum of rabbits injected with purified enzyme. Concentration of the enzyme was immunohistochemically detected in cells which form granulomatous organization, but not in inflammatory cells surrounding the foci. The antibody, however, cross reacted with the enzyme in adjacent liver cells and weakly stained their cytoplasm. The findings indicate that this enzyme, in addition to angiotensin converting enzyme, may serve as a useful biochemical marker for granulomatous tissue reactions.
A clinical evaluation of pyridostigmin bromide in the reversal of curarization

Pyridostigmin bromide in doses of 10 to 20 mg is an effective antagonist of d-tubocurarine when used in the presence of cyclopropane, diethyl ether, methoxyflurane, nitrous oxide, or halothane. When it is used without concurrent atropine, heavy pharyngeal and tracheal secretions are often found, and vagomimetic cardiac arrhythmias are not uncommon. Protection against secretions and vagal arrhythmias can be obtained only with the simultaneous use of 1.0 mg of atropine sulfate. But, at this dose level, transient tachycardia may occur. Pyridostigmin, as a curare antagonist, is approximately one-half as potent as neostigmine, but it has a longer course of action. A plea is made for adequate reversal of curare or the use of postoperative respiratory assistance in all instances where curare is used.
CATALYSIS OF LIPID OXIDATION: A STUDY OF MULLET (Mugil cephalus) DARK FLESH AND EMULSION MODEL SYSTEM

The dark flesh of mullet (Mugil cephalus) was compared with beef muscle for total iron, total hemoprotein, and total nonheme iron. Mullet dark flesh contained 57.3 ppm iron, over twice the amount in beef, 26.0 ppm. Total possible nonheme iron content of mullet dark flesh ranged from 56–75%, compared to 11–29% for beef. In a linoleate emulsion model system, mullet dark flesh homogenate was analyzed for heme and nonheme iron activity as lipid oxidation catalysts. Addition of ascorbic acid, EDTA, and cyanide, at different pH levels, indicated the nature of the catalyses. Of the additives, cyanide yielded the strongest inhibition on a molar basis. Based on the criteria of other researchers, these data suggest that heme iron is the major catalyst of lipid oxidation in mullet flesh. The rates of O2 uptake by mullet dark flesh homogenate and by Fe/EDTA increased with increasing acidity, rather than exhibiting a previously reported peak at pH 5.5. The latter appears to be a phenomenon of limited occurrence rather than a general test criteria. In light of this finding, the nature and nomenclature of biological nonheme iron is discussed.
Mathematical formulae for calculating the base temperature for growing degree days

Much research has been done on finding methods to determine the base temperature, a very important variable in computation of growing degree days (GDD). Four common methods have been reported often in the literature: (1) the least standard deviation in growing degree days; (2) the least standard deviation in days; (3) coefficient of variation; (4) regression coefficient. The procedures to calculate the base temperature associated with these methods are tedious and lack a theoretical basis in mathematics. The objective of this research was to find simple and mathematically sound formulae to calculate the base temperature for GDD. Mathematical formulae are proposed, proved and tested using temperature data for snap bean, sweet corn, and cowpea. Compared with previous procedures, these proposed mathematical formulae can produce the base temperature easily and accurately. These formulae are applicable to calculating the base temperature for GDD of any developmental stage for any crop.
Self-Organization and Learning Disabilities: A Theoretical Perspective for the Interpretation and Understanding of Dysfunction:

Central nervous system dysfunction is common to most definitions of learning disabilities (i.e., the Individuals with Disabilities Education Act, P.L. 101–476 (IDEA), the National Joint Committee on Learning Disabilities (NJCLD), the Interagency Committee on Learning Disabilities (ICLD), although not always explicitly stated. Yet, many practitioners and diagnosticians of learning disabilities (LD) do not have a sufficiently comprehensive understanding of the neurological system to be able to interpret disabling conditions from this view. “Specific” learning disability may be an erroneous concept when one considers the underlying dynamic and recursive interactions within the neurological system. A self-organizing systems (SOS) perspective offers a comprehensive framework for understanding and interpreting the complexity of LD and suggests that classification schema tend to undermine the complex nature of the learning disorder. In this article, self-organizing systems principles are explained, and research ...
Parsing Ink4a/Arf: "pure" p16-null mice.

The proximity of the INK4a and ARF genes carries an obvious risk in the sense that deletions in this chromosomal region will cancel the functions of both tumor suppressors. We still have no explanation for why the two genes overlap structurally. Their unusually intimate relationship suggests that INK4a and ARF might be coregulated, but so far, this is true only in the sense that both are induced when primary cells are explanted into culture. A previous genetic analysis revealed that the two genes might functionally interact in governing replicative senescence (Carnero et al., 2000xCarnero, A., Hudson, J.D., Price, C.M., and Beach, D.H. Nat. Cell Biol. 2000; 2: 148–155Crossref | PubMed | Scopus (232)See all References(Carnero et al., 2000). Moreover, the two proteins have the potential to coordinate signaling through the RB and p53 pathways, because ARF can be induced by E2F transcription factors whose activities are subject to RB-negative regulation (Bates et al., 1998xBates, S., Phillips, A.C., Clarke, P., Stott, F., Peters, G., Ludwig, R.L., and Vousden, K.H. Nature. 1998; 395: 124–125Crossref | PubMed | Scopus (737)See all References(Bates et al., 1998). We do not fully understand these relationships, although they provide evidence for the existence of a signaling network that is central to tumor formation.The finding that melanomas arise preferentially in the background of Ink4a loss and Arf heterozygosity is a great surprise, which suggests a novel relationship between these genes. Like mice lacking Ink4a/Arf, neither Arf-null nor p53-null mice spontaneously develop melanoma. Presumably, it is the level of p19Arf that influences the biologic response to p16Ink4a loss of function in melanocytes. There is great subtlety here, and those who harbor doubts that animal models can be used to replicate human cancer syndromes should take heed.
Apolipoprotein E inhibition of proliferation of mitogen-activated T lymphocytes: Production of interleukin 2 with reduced biological activity

Apolipoprotein E (apoE), but not apoAI or apoCIII, suppresses mitogen-activated T lymphocyte proliferation, independent of the type of activation signal. Both CD4 and CD8 T cells are inhibited. ApoE inhibits T cell proliferation, in part, by reducing the production of bioactive interleukin 2 (IL2). IL2 activity is reduced by approximately 50-65% in cultures of mitogen-stimulated T cells when apoE is present. ApoE does not significantly alter levels of IL2 mRNA or the mass of secreted IL2 protein, quantitated by enzyme immunoassay. Reduced IL2 activity was not a consequence of induction of IL2 inhibitors in response to apoE or effects of apoE on the bioassay. These results suggest that apoE antagonizes post-translational events in mitogen-activated T lymphocytes that are required for the secretion of a bioactive IL2 protein.
Synthesis and structure–property aspects of poly(carbon diselenide)

Poly(carbon diselenide), (CSe2)x, is obtained as a black powder either by thermal polymerization of CSe2 solutions at high pressure, slow thermal polymerization under ambient conditions of neat CSe2, or photopolymerization of CSe2 solutions. X‐ray diffraction measurements indicate that the as‐prepared polymer is highly disordered and does not contain free crystalline or amorphous selenium. This result contrasts with the extensive formation of free selenium in the high pressure, high temperature polymerization of neat CSe2. The electrical conductivity is below 10−6 S cm−1, which is consistent with a band gap of ∼2 eV obtained by diffuse reflection spectroscopy. Details of the thermal properties, and the optical absorption, electron spin resonance, infrared absorption, Raman scattering, and extended x‐ray absorption fine structure (EXAFS) spectra of the polymer are discussed. The EXAFS data clearly indicate that Se–Se bonds (but not Se chains) are present. The resonance‐enhanced Raman and infrared absorptio...
The clinical utility of a vaginal template designed to standardize suture placement during retropubic colposuspensions.

Suture placement and bite size utilizing a vaginal template are compared to a traditional surgical approach during modified retropubic colposuspension on four fresh-frozen human female cadavers. Overall, a larger suture bite was obtained utilizing the template (71.5 ± 4.6 vs 46.7 ± 25.3 mm2, P= 0.001). However, with increased surgical experience the suture bites obtained with the traditional approach and template technique were similar. Inconsistent suture placement relative to the urethrovesical junction and urethra was observed with both techniques. Differences in pelvic floor anatomy make consistent suture placement with respect to the urethrovesical junction and urethra neither possible nor entirely preferable with either technique. There seems to be little clinical value in the use of this vaginal template during modified retropubic colposuspensions.
Feature selection and machine learning with mass spectrometry data for distinguishing cancer and non-cancer samples

Abstract This is a comparative study of various clustering and classification algorithms as applied to differentiate cancer and non-cancer protein samples using mass spectrometry data. Our study demonstrates the usefulness of a feature selection step prior to applying a machine learning tool. A natural and common choice of a feature selection tool is the collection of marginal p -values obtained from t -tests for testing the intensity differences at each m / z ratio in the cancer versus non-cancer samples. We study the effect of selecting a cutoff in terms of the overall Type 1 error rate control on the performance of the clustering and classification algorithms using the significant features. For the classification problem, we also considered m / z selection using the importance measures computed by the Random Forest algorithm of Breiman. Using a data set of proteomic analysis of serum from ovarian cancer patients and serum from cancer-free individuals in the Food and Drug Administration and National Cancer Institute Clinical Proteomics Database, we undertake a comparative study of the net effect of the machine learning algorithm–feature selection tool–cutoff criteria combination on the performance as measured by an appropriate error rate measure.
Tissue-specific distribution and developmental regulation of M and B creatine kinase mRNAs

To characterize the tissue-specific distribution and developmentally regulated expression of M and B creatine kinase mRNA in rats, total cellular RNA was isolated from adult rat tissues and from skeletal muscle, heart, brain and intestine at selected stages of development. Northern blots were prepared and hybridized with M and B subunit-specific probes derived from the 3'-untranslated region. M creatine kinase mRNA was expressed abundantly in heart and skeletal muscle, and less abundantly in lung. B creatine kinase mRNA was found in all tissues examined except liver and was abundant in brain, heart and intestine. The developmentally regulated expression of M and B creatine kinase mRNA was determined in skeletal muscle, heart, brain and intestine. The developmental program of B creatine kinase mRNA was different for each tissue examined. During development, M creatine kinase mRNA was up-regulated in both heart and skeletal muscle with a different regulatory program. This resulted in replacement of B mRNA by M mRNA as the predominant species at an earlier developmental stage in heart when compared to skeletal muscle.
Academic entitlement and socially aversive personalities: Does the Dark Triad predict academic entitlement?

Abstract Academic entitlement is a well-established problem; however its causes are not well understood. This study (n = 169) investigated the role of the Dark Triad as a predictor of academic entitlement. The Dark Triad, comprised of Machiavellianism, narcissism, and psychopathy, was measured with Jonason and Webster’s (2010) concise measure, and academic entitlement was assessed with Chowning and Campbell’s (2009) academic entitlement construct (comprised of externalized responsibility and entitled expectations). Gender and psychopathy predicted externalized responsibility and narcissism predicted entitled expectations. Findings are discussed regarding the contribution of psychopathy and narcissism to academic entitlement. Also discussed is the potential learned aspect of entitlement, due to narcissism being a cause of both entitled behavior and resultant uncivil behavior that occurs when entitled behaviors fail to achieve the desired outcome.
Products of the Gas-Phase Reactions of 1,3-Butadiene with OH and NO3 Radicals

1,3-Butadiene is emitted into the atmosphere from a number of sources including combustion sources and is listed in the United States as a hazardous air pollutant. In the atmosphere, 1,3-butadiene reacts with OH radicals, NO3 radicals, and O3 with the dominant tropospheric removal processes being daytime reaction with the OH radical and nighttime reaction with the NO3 radical. We have used gas chromatography, in situ Fourier transform infrared (FT-IR) absorption spectroscopy, and in situ atmospheric pressure ionization tandem mass spectrometry (API-MS) to identify and quantify the products formed from the reactions of 1,3-butadiene with OH radicals (in the presence of NO) and NO3 radicals. Acrolein, formaldehyde, and furan were identified and quantified from the OH radical-initiated reaction, with formation yields of 0.58 ± 0.04, 0.62 ± 0.05, and 0.03−0.04, respectively. Organic nitrates were observed by FT-IR spectroscopy with an estimated yield of 0.07 ± 0.03, and the API-MS analyses indicated that thes...
Solution phase chemistry of lanthanide complexes. 8. Tb(III) complexes of 1,2-dihydroxybenzene-3,5-disulfonic acid (tiron)

Abstract The solution phase chemistry associated with lanthanide complexes of the title compound has been studied by means of luminescence spectroscopy. The nature of the tiron complexes was found to vary with the particular metal/ligand ratio present in the solution. In 1:1 Tb/tiron solutions, no evidence for a monomeric Tb(tiron) complex could be obtained, and instead all evidence pointed toward the existence of associated complexes. These [Tb(tiron)]x complexes could exist in protonated and deprotonated forms. At metal/ligand ratios of 1:2 and 1:3, monomeric Tb(tiron)2 complexes were found to exist. At the highest ratios of metal/ligand (1:5 and 1:10), evidence was obtained which indicated the existence of monomeric Tb(tiron)3 complexes. These results were not found to agree totally with conclusions drawn in two earlier, conflicting, works employing potentiometic titration methods, but instead demonstrated that the best interpretation actually contains elements of each complexation scheme.
Revision of the NBS tables of spectral-line intensities below 2450 Å

From Abstract: "A calibration is applied to the intensity measurements of the 1400 lines below 2450 A in the NBS Tables of Spectral-Line Intensities. Tables of the new values are presented with the lines arranged by elements and by wavelengths."
Let’s Save Retirement: Repairing America’s Broken System of Funding Workers’ Retirement

Far too few American workers can look forward to financial independence as they age. Many will be obliged to extend their working lives, some into their seventies. A patchwork of defined contribution (DC) retirement plans now serve as the primary retirement saving vehicle in the private sector, but they are complex, costly, and challenging for employers and employees to manage. This article presents a comprehensive set of recommendations for a unified private DC pension system to cover all working Americans, with a single set of rules and without cost to the government. A key part is the creation of broadly diversified trusteed retirement funds (TRFs), whose sponsors are trustees, with fiduciary responsibilities. Employee contributions will automatically go into a broadly diversified TRF unless the employee either opts out or selects a preferred TRF or the employer already sponsors a defined benefit (DB) pension plan. TRFs will relieve employers from fiduciary responsibility for all future DC contributions. To protect retirees from inflation, longevity, and asset price volatility risk, retirees will be encouraged to use their TRF savings to buy either an immediate or deferred indexed annuity. A new government agency, the Federal Longevity Insurance Administration, will enable private insurance companies to provide low-cost annuities.
The Role of Self-concept Clarity in Relationship Quality

Previous research has linked self-concept clarity to positive outcomes (Campbell et al., 1996), but has not systematically explored its potential positive association with relationship quality. The current set of studies hypothesizes that self-concept clarity will positively correlate with relationship satisfaction and commitment, and that inclusion of other in the self and self-esteem will mediate the association. Study 1 examined correlations between self-report measures from 199 undergraduates, while Study 2 randomly assigned 78 undergraduates to either engage in a self-concept clarity or self-concept confusion manipulation. As hypothesized, in both studies, higher self-concept clarity was associated with higher relationship satisfaction and commitment. Inclusion of other in the self and self-esteem mediated the association between self-concept clarity and relationship quality measures (the only exception was for self-esteem and commitment in Study 1). These results demonstrate how a person's self-conc...
Shoshonitic magmas in nascent arcs: New evidence from submarine volcanoes in the northern Marianas

Volcanoes in the northern Mariana arc between Uracas (lat 20°N) and Minami Iwo Jima (24°N) are very active yet entirely submarine. In contrast to the predominantly low-K basaltic magmas of the central Mariana arc, the northern Mariana arc is dominated by more siliceous melts in the south and by shoshonites in the north. The northern arc melts have enrichments in Ba (<800 ppm), Rb (<70 ppm), Sr (<1000 ppm), Ce (<50 ppm), and (Ce/Yb)n (<24) which increase to the north as far as Iwo Jima. Lavas from volcanoes north of Iwo Jima lack these enrichments and are indistinguishable from those of the central Maranas. The shoshonites are unusual in occurring along the magmatic front of a primitive, intra-oceanic arc. We hypothesize that they represent the reconstruction of a magmatic arc following melting of enriched mantle due to the propagation of the Mariana Trough spreading center northward through the Volcano arc. Shoshonites thus may characterize the initial stages of arc construction after an episode of back-arc rifting and need not be restricted to the mature stages of arc evolution. This situation contrasts with subduction-zone initiation, where first melts may be boninites or low-K tholeiites. These differing initial melts converge toward tholeiitic and calc-alkaline compositions as arcs evolve.
Correlation of surface antigens and cell type in cloned cell lines from the rat central nervous system.

Abstract A large group of cloned cell lines from the rat central nervous system has been screened by means of an ion flux assay and classified as excitable or non-excitable. The results essentially confirm previous electrophysiological tests on these cells and allow us to distinguish nerve cells from glial cells. On the basis of this nerve-glia classification, antisera have been prepared which recognize specific surface antigens on the cells. Six cell lines judged to be neuronal express a common antigen N1. Four of these neurons also have the antigen N2, and two of them have a third antigen N3. Glial cells lack all of these antigens, but express either or both of two antigens G1 and G2 which are not found on the nerve cells. Muscle cells, like nerve cells, are excitable, yet the two muscle cell lines examined express none of the nerve-specific antigens; they do express the glial antigen G1. Two as yet unclassified cell lines judged to be excitable by the sodium uptake assay also lack the neuronal antigens but express the second glial antigen G2. In addition there are at least six antigens or determinants which are shared in various combinations by nerve, muscle, glial and fibroblastic cell lines. Cell-specific surface components such as these could be involved in recognition patterns between various cells. Furthermore, these antigens may prove to be useful markers in mapping the lineage of cells in the developing nervous system.
Integers free of large prime factors and the Riemann hypothesis

For x, y ≥ 1, let Ψ(x, y) denote the number of positive integers less than or equal to x and free of prime factors greater than y. The behaviour of the function Ψ(x, y) has been the object of numerous articles (see e.g. Norton's memoir [5] and the bibliography there). It turns out that a good approximation to ψ(x, y)/x is given by ρ(log x/log y), where the function ρ(t) is defined for t ≥ 0 as the continuous solution of the equations
Dynamics and chaos : The spherical pendulum

All but the simplest of dynamical systems contain nonlinearities that play an important role in modeling and simulating physical systems. They create unpredictable (chaotic) behavior that is often hidden or neglected in traditional solutions. A simple dynamical system, the spherical pendulum, is introduced to illustrate issues, principles, and effects of chaos in dynamics. The spherical pendulum is a two degrees of freedom nonlinear system with a pivot point in space. The equations of motion for the pendulum are derived, simulated, and animated. A periodical perturbation is applied to the pivot point producing radically different behavior.
Large rate accelerations in antibody catalysis by strategic use of haptenic charge

General acid-base catalysis contributes substantially to the efficacy of many enzymes, enabling an impressive array of eliminations, isomerizations, racemizations, hydrolyses and carbon-carbon bond-forming reactions to be carried out with high rates and selectivities. The fundamental challenge of exploiting similar effects in designed catalysts such as catalytic antibodies is that of correctly positioning the catalytic groups in an appropriate active-site microenvironment. Charge complementarity between antibody and hapten (the template used to induce an antibody) has been used successfully in a number of instances to elicit acids and bases within immunoglobulin combining sites, but the activities of the catalysts obtained by this strategy are generally considerably lower than those of natural enzymes. Here we report that by optimizing hapten design and efficiently screening the immune response, antibodies can be obtained that act effectively as general base catalysts. Thus a cationic hapten correctly mimicking the transition-state geometry of all reacting bonds and bearing little resemblance to the reaction product has yielded carboxylate-containing antibodies that catalyse an E2 elimination with more than 10(3) turnovers per active site and rate accelerations of greater than 10(8). These results demonstrate that very large effects can be achieved by strategic use of haptenic charge.
Switchgrass establishment as affected by seeding depth and soil type

Abstract Switchgrass (Panicum virgatum L.) has been identified as a potential bioenergy crop for the North Central Region of the USA. One of the limitations to successful production of switchgrass is poor seedling establishment affected by the interaction between seeding depth and soil physical characteristics. The objective of this study was to determine the effect of seeding depth and soil types on switchgrass seedling establishment in a greenhouse and field experiment. The greenhouse experiment included seven seeding depths (0, 13-, 19-, 25-, 38-, 51-, and 64-mm deep), three soil types, and one cultivar, Dacotah. Soil types for the greenhouse experiment were brought in from three North Dakota State University research sites located at Fargo (silty-clay, 6.1% organic matter (OM)), Prosper (fine-silty, 3.3% OM), and Carrington (coarse loamy, 2.5% OM). The field experiment was conducted at Fargo and Prosper, ND, in 2010, and included four seeding depths (13-, 19-, 30-, and 38-mm deep) and two cultivars Dacotah and Forestburg. Results from the greenhouse experiment indicated pure live seed emergence (PLSE) differed among seeding depths and soil textures. Only the surface seeding (0-mm depth) had a significantly lower PLSE. Seeding depths from 13- to 64-mm depth were not significantly different and fluctuated between 64 and 74% PLSE. The silty-clay soil at Fargo had significantly higher PLSE (74%) across all seeding depths than the fine-silty soil at Prosper, and the coarse-loamy soil at Carrington (60% PLSE). In the field experiment, the Forestburg cultivar had very poor emergence at all seeding depths and environments. The PLSE for ‘Forestburg’ was 10%, from the 13-mm depth averaged across both locations. The PLSE for Dacotah across both locations was 80, 42, 18, and 5% for the 13-, 19-, 30-, and 38-mm depths, respectively. Under controlled conditions (greenhouse experiment), seeding depth was not a major factor affecting seedling establishment except for the surface seeding where the lack of seed and soil contact and surface dryness reduced emergence. Pure live seed emergence and emergence index were greater in the silty-clay soil at Fargo across all seeding depths, presumably due to a better seed–soil contact. Under field conditions, the 13-mm depth had significantly higher PLSE indicating other factors are interacting with the seeding depth. As a general recommendation to growers switchgrass should be seeded no deeper than 13-mm depth. Testing the germination of the seed lot, without stratification, before planting is recommended to better estimate field establishment success.
Preferred set selection by iterative key set factor analysis

Abstract The object of preferred set selection is the identification of the minimum set of measurements that best characterizes a multicomponent system. The key set of rows (or columns) of a data matrix is the combination of rows (or columns) most orthogonal to each other. The key set optimizes data reproduction and therefore constitutes the preferred set. This paper describes an iterative refinement of the original key set methodology that ensures the selection of the most orthogonal set of typical vectors. Results of the iterative algorithm are compared with the noniterative procedure using a variety of data sets.
Comparison of fungal viability assays using Candida albicans yeast cells undergoing prolonged incubation in the absence of nutrients: Untersuchungen zur Überlebensfähigkeit von Candida albicans bei Langzeitinkubation in Mangelsubstraten

Summary. Staining methods for determining fungal viability are usually assessed by comparisons with enumeration of colony-forming units (CFU) on solid media. The purpose of the present study was to compare viability as assessed by the acridine orange (AO) and MTT methods with the numbers of CFUs obtained for Candida albicans yeast cells undergoing prolonged incubation in distilled water. In initial assessments of the assays using various proportions of control and heat-killed C. albicans, the AO and MTT methods consistently indicated significantly higher values for viability than did CFU determinations. Experiments using organisms cultured overnight revealed that ≅95% of the cells were capable of dividing at least once in a microscopic proliferation assay, whereas only 69% were capable of forming colonies. Parallel assays comparing AO uptake and MTT reduction gave excellent agreement with the microscopic proliferation assay, but not with CFU determinations. Using organisms undergoing prolonged incubations in distilled water, much lower viabilities were obtained with the CFU method at 7 and 10 days than with the microscopic proliferation assay or the two staining methods. These results indicate that the AO and MTT assays correlate well with the ability of C. albicans to divide at least once, but may not accurately indicate the percentage of organisms actually able to form colonies. Zusammenfassung. Farbemethoden zur Bestimmung der Lebendkeimzahl werden ublicherweise bewertet durch Vergleich der Zahlen koloniebildender Einheiten (CFU) auf festen Nahrmedien. Zweck der vorliegenden Studie war, die Erfassung der Lebensfahigkeit mittels Akridinorange (AO) oder MTT anhand der CFU-Zahlen von Candida albicans zu prufen, die in Langzeitkonservierung in destilliertem Wasser gehalten wurde. In der ersten Versuchsserie mit unterschiedlichen Proportionen von unbehandelten und hitzebehandelten C. albicans-Zellen zeigten sowohl die AO- als auch die MTT-Methode signifikant hohere Uberlebensraten als die CFU-Bestimmungen. Experimente mit Ubernachtkulturen ergaben, das etwa 95% aller Zellen in der Lage waren, sich in einem mikroskopischen Proliferationsansatz wenigstens einmal zu teilen, wuhrend nur 69% in der Lage waren, Kolonien zu bilden. In Versuchen mit Hefen unter verlungerter Aufbewahrung in Aqua dest. wurden viel niedrigere Uberlebensraten mit der CFU-Methode nach 7 und 10 d Bebrutung als mit dem mikroskopischen Proliferationsansatz oder den beiden Furbemethoden bestimmt. Die Ergebnisse zeigen, das die AO- und MTT-Ansutze gut mit der Fuhigkeit von C. albicans korrelieren, sich wenigsten einmal zu teilen, das sie aber nicht den Prozentsatz von Organismen widerspiegeln, der in der Lage ist, tatsuchlich Kolonien zu bilden.
Structure of the social network and its influence on transmission dynamics in a honeybee colony

Infectious processes in a social group are driven by a network of contacts that is generally structured by the organization arising from behavioral and spatial heterogeneities within the group. Although theoretical models of transmission dynamics have placed an overwhelming emphasis on the importance of understanding the network structure in a social group, empirical data regarding such contact structures are rare. In this paper, I analyze the network structure and the correlated transmission dynamics within a honeybee colony as determined by food transfer interactions and the changes produced in it by an experimental manipulation. The study demonstrates that widespread transmission in the colony is correlated to a lower clustering coefficient and higher robustness of the social network. I also show that the social network in the colony is determined by the spatial distribution of various age classes, and the resulting organizational structure provides some amount of immunity to the young individuals. The results of this study demonstrates how, using the honeybee colony as a model system, concepts in network theory can be combined with those in behavioral ecology to gain a better understanding of social transmission processes, especially those related to disease dynamics.
Focused Web searching with PDAs

The Stanford Power Browser project addresses the problems of interacting with the World-Wide Web through wirelessly connected Personal Digital Assistants (PDAs). These problems include bandwidth limitations, screen real-estate shortage, battery capacity, and the time costs of pen-based search keyword input. As a way to address bandwidth and battery life limitations, we provide local site search facilities for all sites. We incrementally index Web sites in real time as the PDA user visits them. These indexes have narrow scope at first, and improve as the user dwells on the site, or as more users visit the site over time. We address the keyword input problem by providing site specific keyword completion, and indications of keyword selectivity within sites. The system is implemented on the Palm Pilot platform, using a Metricom radio link. We describe the user level experience, and then present the analyses that informed our technical decisions.
Impact With Friction

A theory of the impact or collision of two rigid bodies, taking account of friction, is presented. It determines how the direction of sliding varies during the impact, which must be known to calculate the direction of the frictional force and thence the frictional impulse. This is accomplished by analyzing the equations of motion of the bodies during the collision. The normal impulse is determined by using a coefficient of restitution. When the direction of sliding is constant throughout the collision, the theory agrees with that given by Whittaker, which is correct only in this case.
Esophageal Stents for Severe Strictures in Young Children: Experience, Benefits, and Risk

The use of esophageal stents has been commonplace in adults for many years and for a variety of indications, including palliative care for malignant lesions involving the esophagus. The use of esophageal stents in the pediatric population, however, was limited by the inability to remove them and the implications this has for the growing child, especially for primarily benign esophageal lesions. With the advent of removable, covered stents, the potential uses for stents in children expanded to include treatment of a wide variety of congenital and acquired esophageal strictures. Stenting offers tremendous potential advantage over more traditional pneumatic or bougie dilation in its ability to provide continuous, radially oriented dilation pressure sustained over a period of time. This review examines the published pediatric literature on stents, discusses the indications for their use, outlines the types of stents available, offers technical guidance for proper placement, and reviews subsequent management and complications.
Interplay of Axial Ligation, Hydrogen Bonding, Self-Assembly, and Conformational Landscapes in High-Spin Ni(II) Porphyrins

The molecular structures of four bis-ligated high-spin Ni(II) complexes of the sterically crowded, nonplanar 2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetranitroporphyrin (NiOETNP) are reported. The ligands are imidazole (Im), imidazole plus 2-methylimidazole (2-MeIm) in the crystal lattice, 1-methylimidazole (1-MeIm), and 2,1,3-benzoselenadiazole (BSeD). Extensive intermolecular hydrogen bonding is observed in the three imidazole-ligated structures consisting of NH···O and CH···O bonding from the imidazoles to neighboring nitro groups and of NH···N interactions to a nearby 2-MeIm. The different modes of hydrogen bonding, typical of those frequently observed in proteins, mediate the self-assembly of discrete porphyrin dimers as well as more extensive two- and three-dimensional arrays. Only the bis-BSeD complex remains monomeric. The presence or absence of the different types of hydrogen bonds controls the orientations of the axial ligands and also modulates the conformations of the porphyrin skeletons. Thi...
Will we be able to ‘spot’ an effective HIV-1 vaccine?

Many HIV-1 vaccine efforts have heavily emphasized class I-restricted CD8(+) cytotoxic T lymphocytes (CTLs) as a potentially important arm of immunity. Commonly used CTL assays describe only specificity and frequency, and not antiviral effects. However, increasing evidence indicates that CTL antiviral function is determined by the complex interplay of multiple virologic and cellular factors, and thus these measurements are an incomplete reflection of CTL efficacy. Our current understanding of the factors determining HIV-1-specific CTL antiviral efficacy is inadequate to interpret fully the significance of detected CTLs in vaccine and pathogenesis studies. To assess CTLs as a protective immune response, it will be crucial to elucidate these mechanisms and/or devise new assays that directly reflect the interaction of CTLs and HIV-1.
The secondary structure and sequence optimization of an RNA ligase ribozyme

In vitro selection can generate functional sequence variants of an RNA structural motif that are useful for comparative analysis. The technique is particularly valuable in cases where natural variation is unavailable or non-existent. We report the extension of this approach to a new extreme--the identification of a 112 nt ribozyme secondary structure imbedded within a 186 nt RNA. A pool of 10(14) variants of an RNA ligase ribozyme was generated using combinatorial chemical synthesis coupled with combinatorial enzymatic ligation such that 172 of the 186 relevant positions were partially mutagenized. Active variants of this pool were enriched using an in vitro selection scheme that retains the sequence variability at positions very close to the ligation junction. Ligases isolated after four rounds of selection catalyzed self-ligation up to 700 times faster than the starting sequence. Comparative analysis of the isolates indicated that when complexed with substrate RNAs the ligase forms a nested, double pseudo-knot secondary structure with seven stems and several important joining segments. Comparative analysis also suggested the identity of mutations that account for the increased activity of the selected ligase variants; designed constructs incorporating combinations of these changes were more active than any of the individual ligase isolates.