cssi/SciSciGPT-SciSciNet huggingface dataset:
Alkylation of cysteine 41, but not cysteine 200, decreases the ADP-ribosyltransferase activity of the S1 subunit of pertussis toxin.

Sulfhydryl-alkylating reagents are known to inactivate the NAD glycohydrolase and ADP-ribosyltransferase activities of the S1 subunit of pertussis toxin, a protein which contains two cysteines at positions 41 and 200. It has been proposed that NAD can retard alkylation of one of the two cysteines of this protein (Kaslow, H.R., and Lesikar, D.D. (1987) Biochemistry 26, 4397-4402). We now report that NAD retards the ability of these alkylating reagents to inactivate the S1 subunit. In order to determine which cysteine is protected by NAD, we used site-directed mutagenesis to construct analogs of the toxin with serines at positions 41 and/or 200. Sulfhydryl-alkylating reagents reduced the ADP-ribosyltransferase activity of the analog with a single cysteine at position 41; NAD retarded this inactivation. In contrast, sulfhydryl-alkylating reagents did not inactivate analogs with serine at position 41. An analog with alanine at position 41 possessed substantial ADP-ribosyltransferase activity. We conclude that alkylation of cysteine 41, and not cysteine 200, inactivates the S1 subunit of pertussis toxin, but that the sulfhydryl group of cysteine 41 is not essential for the ADP-ribosyltransferase activity of the toxin. These results suggest that the region near cysteine 41 contributes to features of the S1 subunit important for ADP-ribosyltransferase activity. Using site-directed mutagenesis, we found that changing aspartate 34 to asparagine, arginine 39 to lysine, and glutamine 42 to glutamate had little effect on ADP-ribosyltransferase activity. However, substituting an asparagine for the histidine at position 35 markedly decreased, but did not eliminate, ADP-ribosyltransferase activity. Chou-Fasman analysis predicted no significant modifications in secondary structure of the S1 peptide with the change of histidine 35 to asparagine. Thus, histidine 35 may interact with a substrate of the S1 subunit without being essential for catalysis.
Rural Changes Stimulate Rising Giants

The Dragon and the Elephant . Agricultural and Rural Reforms in China and India. Ashok Gulati and Shenggen Fan, Eds . Johns Hopkins University Press, Baltimore, 2007. 574 pp. $75. ISBN 9780801887864. Paper, $38. ISBN 9780801887871. Published for the International Food Policy Research Institute. Exploring the reasons for the dramatic growth of the rural economies of China and India over the past few decades, the authors consider what lessons can be applied to other developing nations and to the problems of poverty in these two countries.
CASCADE AND STEPWISE LASER SPECTROSCOPY OF ALKALI ATOMS

A little more than one hundred years ago atomic spectroscopy began at Heidelberg with the work of Bunsen and Kirchnoff on the beautiful colors of flames seeded with salts of sodium and potassium. Intrigued by certain peculiar lines in the spectra of Durkheim mineral water, Bunsen evaporated forty tons of water to isolate the first small samples of rubidium and cesium salts. Remarkably, the properties of those same alkali atoms continue to fascinate us today, and I am going to talk about the surprising results of some recent experimental investigations of the fine structure and hyperfine structure of alkali atoms. Most of this work has been done by two talented young men, Rajendra Gupta of Columbia University and Sune Svanberg of Goteborg University. They have been assisted by a number of able students whom I will mention later.
The influence of different fixatives and fixation methods on the ultrastructure of rat kidney proximal tubule cells. II. Effects of varying osmolality, ionic strength, buffer system and fixative concentration of glutaraldehyde solutions.

The influence of different glutaraldehyde fixatives on the ultrastructure of proximal tubule cells in the rat kidney was studied. The fixative solutions were systematically varied with respect to sodium chloride concentration, buffer system and glutaraldehyde concentration. The ultrastructure of the proximal tubule cells differed markedly when the sodium chloride concentration of the fixative vehicle was varied. Smaller, yet significant, differences were observed when the concentration of glutaraldehyde was changed. Almost no differences were found between differently buffered glutaraldehyde fixatives when the buffers had approximately the same osmolality.
A continuous, wearable, and wireless heart monitor using head ballistocardiogram (BCG) and head electrocardiogram (ECG)

Continuous and wearable heart monitoring is essential for early detection and diagnosis of cardiovascular diseases. We demonstrate a continuous, wearable, and wireless heart monitor that is worn at the ear. The device has the form factor of a hearing aid and is wirelessly connected to a PC for data recording and analysis. With the ear as an anchoring point, the heart monitor measures the ballistocardiographic (BCG) motion of the head using a MEMS tri-axial accelerometer, which is an electrode-less method to measure heart rate. Additionally, electrocardiogram (ECG) is measured locally near the ear using a single-lead configuration. The peak timing delay between the head ECG and the head BCG, or RJ interval, can be extracted in the presence of noise using cross-correlation. The RJ interval is shown to correlate to the heart's pre-ejection period during both Valsalva and whole-body tilt maneuvers.
1D system identification of buildings during earthquakes by seismic interferometry with waveform inversion of impulse responses—method and application to Millikan library

Two new algorithms have been introduced as a further development of a robust interferometric method for structural health monitoring (SHM) of buildings during earthquakes using data from seismic sensors. The SHM method is intended to be used in an automatic seismic alert system, to issue a warning of significant damage during or immediately after the earthquake, and facilitate decision making on evacuation, to avoid loss of life and injury from possible collapse of the weekend structure during aftershock shaking. The method identifies a wave velocity profile of the building by fitting an equivalent layered shear beam model in impulse response functions (virtual source at roof) of the recorded earthquake response. The structural health is monitored by detecting changes in the identified velocities in moving time windows, the initial window being used as reference. Because the fit involves essentially matching phase difference between motion at different floors, the identified velocity profile is not affected by rigid body rocking, and soil-structure interaction in general, as demonstrated in this paper. Consequently, detected changes in wave velocity during an earthquake are not affected by changes in the soil-foundation system, which is a major advantage over SHM by detecting changes in the observed modal frequencies. Further, the method is robust when applied to real buildings and large amplitude earthquake response, as demonstrated in previous work. The new fitting algorithms introduced are the nonlinear least squares (LSQ) fit and the time shift matching (TSM) algorithms. The former involves waveform inversion of the impulse responses, and the latter - iterative matching of the pulse time shifts, both markedly reducing the identification error as compared to the previously used direct ray algorithm, especially for more detailed models, i.e., with fewer floors per layer. Results are presented of identification of the NS, EW and torsional responses of the densely instrumented Millikan Library (9-story reinforced concrete building in Pasadena, California) during a small earthquake.
Experimental and computational investigation of local scour around bridge piers

Abstract Experiments and numerical simulations are carried out to study clear-water scour around three bridge piers with cylindrical, square, and diamond cross-sectional shape, respectively. To handle movable-bed channels with embedded hydraulic structures, the fluid–structure interaction curvilinear immersed boundary (FSI-CURVIB) method is employed. The hydrodynamic model solves the unsteady Reynolds-averaged Navier–Stokes (URANS) equations closed with the k - ω turbulence model using a second-order accurate fractional step method. Bed erosion is simulated by solving the sediment continuity equation in the bed-load layer using a second-order accurate unstructured, finite-volume formulation with a sand-slide, bed-slope-limiting algorithm. Grid sensitivity studies are carried out to investigate the effect of grid resolution on the predictive capability of the model. Comparisons of the simulations with the experimental data show that for all three cases the agreement is reasonable. A major finding of this work, however, is that the predictive capability of the URANS morphodynamic model improves dramatically for the diamond shape pier for which sediment transport is driven primarily by the shear layers shed from the pier sharp edges. For piers with blunt leading edge, on the other hand, as the circular and square shapes, the URANS model cannot resolve the energetic horseshoe vortex system at the pier/bed junction and thus significantly underpredicts both the scour depth at the nose of the pier and the rate of scour growth. It is also shown that ad hoc empirical corrections that modify the calculated critical bed shear stress to enhance scour rate in the pier leading edge need to be applied with caution as their predictive capabilities are not universal but rather depend on the pier shape and the region of the flow.
Frequency response of piezoresistive-based MASA resonators with electrostatic vertical comb-drive actuation

We report on experimental work that characterizes the frequency response of resonators of Microfabricated Acoustic Spectrum Analyzer (MASA) devices which were fabricated using Sandia's SUMMiT processing technology. A 1.1 micron silicon nitride layer was used in the fabrication to isolate the sense mechanism from the actuation mechanism. The devices are actuated using electrostatic vertical comb-drive actuation in a 30-50 mTorr vacuum and the frequency response is measured using a piezo-resistive readout mechanism. Two MASA devices are tested using comb-drive ac signals (e.g., 200mV) superimposed on a dc bias (e.g., 15V). In addition, dc bias voltages placed on the comb-drive are shown to tune the resonant frequency of the resonator. The frequency response of the piezo-resistive readout mechanism is measured using a 10V dc supply voltage supplied across its Wheatstone bridge. The results show that the piezo-resistive readout mechanism can detect resonant behavior and determine resonant frequency. A laser doppler vibrometer is used as an independent means to characterize the frequency response and verify the results.
In vivo studies of the release of adenine 5′‐nucleotides, adenosine, and its metabolites from the rat brain

Adenosine 5' -triphosphate (ATP) and adenosine function as an excitatory neurotransmitter and a neuromodulator, respectively, in the central nervous system. Neuroexcitatory effects of ATP are mediated by P2X receptors: neuromodulator effects of adenosine by A 1 , A 2 , or A 3 receptors. There is also evidence that ATP, acting a P2Y receptor, is involved in osmoregulatory responses to cell swelling. Studies on the release of ATP and/or adenosine into the interstitial fluid of the brain have served to clarify their roles in cerebral function. ATP release occurs during electrical or K + -induced depolarization of cerebral tissues. Released ATP is rapidly hydrolyzed by ectonucleotidases, which may be released concurrently, to form adenosine 5'-diphosphate (ADP) and adenine 5'-monophosphate (AMP). In addition to synaptic release from neurons, there is evidence of glial release via gap-junction hemichannels. Hydrolysis of AMP to adenosine initiates a further metabolic cascade with the formation of inosine, hypoxanthine, xanthine, and uric acid by adenosine deaminase, purine nucleoside phosphorylase, and xanthine oxidase. Hypoxanthine can be converted to inosine monophosphate by hypoxanthine phosphoribosyl transferase and thus used to replenish ATP. Cerebral ischemia causes ATP utilization, and adenosine formation. Adenosine can then be transported across the plasma membrane and released into the interstitial space. Hypoxemia-evoked adenosine release from the cerebral cortex is inhibited by blockers of adenosine transport. Inhibition of purine metabolism by blockers of adenosine deaminase, purine nucleoside phosphorylase, and xanthine oxidase elevates upstream levels of adenosine and its metabolites. Exposure of the in vivo rat cerebral cortex to cerebrospinal fluid containing swelling-inducing monocarboxylic acids elevated interstitial fluid levels of ADP and AMP, but not of adenosine. Taken together, these studies have led to a greater understanding of the metabolism and release of adenosine and the adenine nucleotides in the normoxic and ischemic brain.
Perivascular hemosiderin deposition in muscle in Waldenström's macroglobulinemia

A 63-year old woman with Waldenstrom's macroglobulinemina of 5 years' duration developed disabling pain in her extremities. The patient had required frequent plasmapheresis and transfusion for treatment of hypervisosity. Muscle biopsy from 2 separate sites showed striking deposition of hemosiderin in macrophages surrounding small vessels and features of slight denervation. Immunofluorescence demonstrated IgM deposition in vessel walls. Perivascular hemosiderin deposition in muscle has not previously been desicribed and may reflect traansfusion-hemosiderosis in a patient with a dysglobulinemia.
Improving Reading Comprehension of At-Risk High-School Students: The ART of Reading Program.

Participants (115 low-socioeconomic-status [SES], inner-city, high-school students) were exposed to three reading conditions: (1) a control condition in which students silently read brief selected passages; (2) an experimental condition in which students were prompted to perform a three-part (Ask, Read, and Tell [ART]) comprehension enhancement exercise before, during, and after reading the selected passages; and (3) another experimental condition in which ART was followed by peer discussion (PD) of the reading. Students answered 10 comprehension questions after reading passages under each condition, which served as the dependent variable. Results of a repeated-measures analysis of variance revealed a significant main effect, and follow-up analysis showed significantly higher levels of comprehension on ART + PD passages relative to either the control or ART passages. Discussion focuses on using PD to enhance comprehension and future research to determine which combination of intervention components are necessary to occasion enhanced comprehension. © 2010 Wiley Periodicals, Inc.
Correction: Video reports as a novel alternate assessment in the undergraduate chemistry laboratory

Correction for ‘Video reports as a novel alternate assessment in the undergraduate chemistry laboratory’ by Mitzy A. Erdmann and Joe L. March, Chem. Educ. Res. Pract., 2014, 15, 650–657.
EXTRAGALACTIC X-RAY SOURCES

The x-ray and optical properties of extragalactic x-ray sources are discussed. The correlations recently found between the optical and x-ray properties of rich clusters of galaxies that could be present among the so far unidentified high-latitude 3U sources are described. 23 references. (auth)
Ella Thea Smith and the Lost History of American High School Biology Textbooks

Two influential articles published in the 1970s suggested that pressure from Christian fundamentalists, subsequent to the Scopes trial of 1925, forced American high school biology textbook authors and publishers to significantly limit discussion of the topic of evolution. The conclusions reached by these studies have become foundational for historians examining the interplay between science and religion in the United States in the twentieth century. However, a reexamination of key twentieth century biology textbooks suggests that the narrative that the treatment of the theory of evolution was held hostage to anti-rational cultural forces is largely a myth, created first as part of a public relations effort by the Biological Sciences Curriculum Study (BSCS) to differentiate, defend, and promote its work, and later as part of an attempt by scholars to sound a warning concerning the rise of the religious right. A focus on this narrative has not only allowed biologists to sidestep uncomfortable questions regarding the race-biased and class-biased assumptions embedded within the concept of evolutionary progress, it has also limited reliance on the texts in question as reliable reflections of the cultural assumptions of educators and scientists. A reexamination of the most popular American biology textbooks from 1907 to 1963, particularly the work of Ella Thea Smith, provides evidence in support of these contentions.
Response of the lateral motor column to multiple forelimbs in Rana pipiens.

The lateral motor columns of a recently metamorphosed frog (Rana pipiens) that had three functional forelimbs on the left side were analyzed for differences on the two sides of the spinal cord. It was found that there was no gross hyperplasia on the left side, nor were there significant differences between the mean nuclear areas of the cells of the two sides. Significant differences did occur, however, in the distribution of nuclear sizes of the two sides. A greater proportion of the cells of the left side had large nuclear areas than did those of the right side. This points to a response of the lateral motor column to an increased periphery by increasing sizes of certain cells rather than by increasing cell numbers.
The longitudinal occurrence and impact of comorbid chronic pain and chronic depression over two years in continuing care retirement community residents.

Objective. To describe the longitudinal course of depressive symptoms and pain experienced by continuing care retirement community (CCRC) residents and to investigate the impact of comorbid chronic activity-limiting pain and chronic high depressive symptoms on physical functioning and health service use. Methods. This longitudinal study of 169 CCRC residents involved five assessments (baseline and four in-person interviews at 6-month intervals). The Geriatric Depression Scale (GDS), questions drawn from the McGill Pain Questionnaire, and self-report data on physical functioning and health care use were assessed. Individuals reporting activity-limiting pain and those with GDS scores ≥11 at three or more assessments were considered to have chronic pain or chronic depression, respectively. The analysis sample included 169 CCRC residents. Multivariate logistic regression was used to test hypotheses. Results. Pain and depressive symptoms were characterized by longitudinal stability. Of the sample, 37% met the criteria for chronic activity-limiting pain, 21% met the criteria for chronic high depressive symptoms, and 13% were comorbid. Adjusting for age and health conditions, those with chronic activity-limiting pain were five times more likely than those in the lowest pain group to persistently be in the worst two quartiles of physical functioning, as were those with even one GDS score >5. The odds of poor physical functioning were 11.2 times greater in those with comorbid chronic pain and depression. Comparable greater odds were seen in this sample for frequency of medical care visits (adjusted odds ratio AOR]=12.4) and consistently high use of all medical services (AOR=3.5). Conclusions. Pain and depressive symptoms were both common and appeared remarkably stable over time. Depressive symptoms contributed significantly to the prediction of impairment associated with pain, and identification and treatment of such symptoms, even minor symptoms, could reduce pain-related impairment and health care costs in the elderly.
Altered Ryanodine Receptor Function in Central Core Disease: Leaky or Uncoupled Ca2+ Release Channels?

Central core disease (CCD) is an autosomal-dominant human congenital myopathy that is associated with at least 22 different mutations in the skeletal muscle isoform of ryanodine receptor (RyR1). CCD mutations in RyR1 have been proposed to lead to the formation of sarcoplasmic reticulum (SR) Ca(2+) release channels that are excessively leaky to Ca(2+). Although some of the CCD mutations in RyR1 may indeed result in leaky SR Ca(2+) release channels, the leaky-channel hypothesis may not represent the only mechanism for muscle weakness in this disorder. The presence of an alternate mechanism of muscle weakness in CCD is supported by the observation that muscle cells expressing a CCD mutation in the putative pore-forming segment of RyR1 (I4898T) exhibit a functional uncoupling of SR Ca(2+) release from sarcolemmal depolarization. These observations cannot be explained by the leaky-channel hypothesis and indicate that muscle weakness in some forms of CCD arises from an alternate and completely unexpected mechanism, termed "excitation-contraction uncoupling."
Cytology of Chinese and North Indian sugarcanes

S. sinense clones in the USDA World Collection are classified on the basis of chromosome number and gross morphology. The following groups are recognized: Mungo 2n = 81, 82, and 83 Dhaulu 2n = 82 and 83 Saretha 2n = 91, 91 + frag ments, and 92 Nargori 2n = 105–119 and 124 Pansahi 2n = 106–120 Unclassified 2n = c104-121 In this classification, the Sunnabile group of previous workers is omitted because none of the clones studied could be assigned to it. Hypotheses that presume aneuploid interspecific hybrid parentage for these clones are accepted. The irregular meiotic behavior and subsequent irregular chromosome transmission of such aneuploid hybrids suffices to explain chromosome numbers in these groups.
Unique Anionic Eight-Connected Net with 36418536 Topology Derived from a Rare Co6(μ3-OH)2(μ-H2O)(CO2)12 Building Block

[(CH3)2NH2]2[Co6(μ3-OH)2(μ-H2O)(ip)6]·2.5H2O (1), where ip2− is the 1,3-benzenedicarboxylate dianion, has been prepared by the solvothermal self-assembly of CoCl2 and H2ip in N,N′-dimethylformamide. Complex 1 contains a rare Co6(μ3-OH)2(μ-H2O)(CO2)12 building block with six crystallographically distinct cobalt(II) ions, one with a trigonal bipyramidal, two with a pseudotetrahedral, and three with a pseudooctahedral coordination environment; the bridging ip2− dianions serve as spacers to yield a unique anionic eight-connected net with 36418536 topology. The magnetic properties of 1 indicate that the six cobalt(II) ions are paramagnetic with, at most, very weak intramolecular antiferromagnetic exchange coupling.
A new 2-D chiral coordination polymer of [Zn(nicotinate)2]n

Abstract A new two-dimensional (2-D) acentric coordination polymer, [Zn(NA)2] 2, has been synthesized under hydrothermal reaction conditions. The structure of 2 is self-assembled from square-grid nets stacked via interdigitation and crystallizes in a chiral space group Fdd2. The zinc atoms are in distorted tetrahedral sites.
Provider Views of Harm Reduction Versus Abstinence Policies Within Homeless Services for Dually Diagnosed Adults

Harm reduction is considered by many to be a legitimate alternative to abstinence-based services for dually diagnosed individuals, yet there is limited understanding of how varying approaches affect front-line practice within services for homeless adults. This paper examines how front-line providers working with individuals who have experienced homelessness, serious mental illness, and addiction view policies of harm reduction versus abstinence within two different approaches to homeless services: the traditional or “treatment first” approach that requires abstinence, and the more recent housing first approach that incorporates harm reduction. As part of a federally funded qualitative study, 129 in-depth interviews conducted with 41 providers were thematically analyzed to understand how providers view harm reduction versus abstinence approaches. Themes included the following: (a) harm reduction as a welcomed alternative, (b) working with ambiguity, and (c) accommodating abstinence. Drawing on recovery principles, the authors consider the broader implications of the findings for behavioral health care with this population.
The structures of albite and jadeite composition glasses quenched from high pressure

Abstract The structures of jadeite and albite composition glasses quenched from 10 and 15 kbar, respectively, have been studied using radial distribution analysis. It is found that aluminum does not undergo a coordination increase at these pressures, in agreement with recent Raman and NMR studies of these glass compositions. Radial distribution functions (RDF's) indicate that the structural response of albite and Jadeite composition melts to pressure up to 10–15 kbar has to do primarily with a distortion of the tetrahedral sites, a slight collapse of the tetrahedral rings forming the framework, and a small loss of short range order resulting in a more densely packed framework structure. The RDF's do not provide any clues concerning T-O-T angular changes at these pressures. It is suggested that the observed structural changes should be closely related to those that take place in melts of rhyolitic composition. Such changes in rhyolitic melts would result in a density increase and viscosity decrease with increasing pressure similar to that observed for melts of albite and jadeite composition.
Automating exercise generation: a step towards meeting the MOOC challenge for embedded systems

The advent of massively open online courses (MOOCs) poses several technical challenges for educators. One of these challenges is the need to automate, as much as possible, the generation of problems, creation of solutions, and grading, in order to deal with the huge number of students. We collectively refer to this challenge as automated exercise generation. In this paper, we present a step towards tackling this challenge for an embedded systems course. We present a template-based approach to classifying problems in a recent textbook by Lee and Seshia, and outline approaches to problem and solution generation based on mutation and satisfiability solving. Several directions for future work are also outlined.
THE MECHANISM OF COPOLYMER RETENTION IN INTERACTIVE POLYMER CHROMATOGRAPHY. II. GRADIENT SEPARATION

The molecular-statistical theory of polymer solutions in confined media is applied to the conventional chromatographic theory of gradient elution. This approach leads to the prediction of the special mode of interactive polymer chromatography: gradient elution at critical point of adsorption. We demonstrate theoretically and experimentally that under appropriate conditions elution of each compositionally homogeneous fraction of copolymer occurs at the critical mobile phase composition. This critical mobile phase composition depends only on the local structure of the copolymer chain and is independent of its molecular weight. As a consequence, gradient elution produces the chemical composition distribution of the copolymer. The theory provides the quantitative conditions for statistical copolymer chains to have a single transition point. Equations describing relationships between the critical eluent composition and the chemical composition and microstructure of macromolecules are developed. The experimenta...
Design considerations for the gyro-peniotron oscillator

The gyro-peniotron shows great promise as a source of microwave radiation. In this paper we investigate the stability and the non-linear saturated efficiency of a gyropeniotron oscillatro with an axis encircling beam operating at the TE211 and the TE311 cylindrical cavity modes. Beam and cavity parameters for stable high efficiency operation are presented from a linear theory analysis of the start-oscillation condition. Using design parameters taken from the linear analysis, the strong field non-linear emission efficiencies are studied numerically. The sensitivity of the saturated efficiency to beam axial velocity and guiding center spread is also considered. The results of our modeling indicate that high efficiency (70–90%) operation of the gyro-peniotron oscillator is possible, even with large guiding center\((\delta r_{gc_ \circ } \mathop< \limits_ \sim 0.2 - 0.4r_{L_ \circ } )\) and large axial velocity\((\delta \beta _{||} \mathop< \limits_ \sim 0.3\beta _{||_ \circ } )\) spread.
Targeted mapping of quantitative trait locus regions for rhizomatousness in chromosome SBI-01 and analysis of overwintering in a Sorghum bicolor × S. propinquum population.

While rhizome formation is intimately associated with perennialism and the derived benefit of sustainability, the introduction of this trait into temperate-zone adapted Sorghum cultivars requires precise knowledge of the genetics conditioning this trait in order to minimize the risk of weediness (e.g., Johnsongrass, S. halepense) while maximizing the productivity of perennial sorghum. As an incremental step towards dissecting the genetics of perennialism, a segregating F4 heterogeneous inbred family derived from a cross between S. bicolor and S. propinquum was phenotyped in both field and greenhouse environments for traits related to over-wintering and rhizome formation. An unseasonably cold winter in 2011 provided high selection pressure, and hence 74.8 % of the population did not survive. This severe selection pressure for cold tolerance allowed the resolution of two previously unidentified over-wintering quantitative trait locus (QTL) and more powerful correlation models than previously reported. Conflicting with previous reports, a maximum of 33 % of over-wintering variation could be explained by above-ground shoot formation from rhizomes; however, every over-wintering plant exhibited rhizome growth. Thus, while rhizome formation is required for over-wintering, other factors also determine survival in this interspecific population. The fine mapping of a previously reported rhizome QTL on sorghum chromosome SBI-01 was conducted by targeting this genomic region with additional simple sequence repeat markers. Fine mapping reduced the 2-LOD rhizome QTL interval from ~59 to ~14.5 Mb, which represents a 75 % reduction in physical distance and a 53 % reduction in the number of putative genes in the locus.
Characterization of Saccharomyces cerevisiae Atm1p. Functional studies of an ABC7 type transporter

Saccharomyces cerevisiae Atm1p has been cloned, over-expressed and purified from a yeast expression system. The sequence includes both the soluble ATPase and transmembrane-spanning domains. With the introduction of an N-terminal Kozak sequence and a C-terminal (His)(6)-tag, a yield of 1 mg of Atm1p was obtained from 3 g wet yeast cells, which is comparable to other membrane-associated proteins isolated from eukaryotic expression systems. The ATPase activity of Atm1p is sensitive to sodium vanadate, a P-type ATPase inhibitor, with an IC(50) of 4 microM. MgADP is a product inhibitor for Atm1p with an IC(50) of 0.9 mM. The Michaelis-Menten constants V(max), K(M) and k(cat) of Atm1p were measured as 8.7+/-0.3 microM/min, 107+/-16 microM and 1.24+/-0.06 min(-1), respectively. A plot of ATPase activity versus concentration of Atm1p exhibits a nonlinear relationship, suggesting an allosteric response and an important role for the transmembrane domain in mediating both ATP hydrolysis and MgADP release. The metal dependence of Atm1p ATPase activity demonstrated a reactivity order of Mg(2+)>Mn(2+)>Co(2+), while each divalent ion was found to be inhibitory at higher concentrations. The activation and inhibitory effect of phospholipids suggest that formation of a lipid-micelle complex is important for enzymatic activity and stability. Structural analysis of Atm1p by CD spectroscopy suggested a similarity of secondary structure to that found for other members of this ABC protein family.
EXOTIC EUROPEAN EARTHWORM INVASION DYNAMICS IN NORTHERN HARDWOOD FORESTS OF MINNESOTA, USA

European earthworms are invading previously worm-free hardwood forests across Minnesota and the Great Lakes region. In many of these forests, earthworm invasions have been associated with the loss of a previously thick forest floor. The ability of earth- worms to alter and control ecosystem processes has been demonstrated in agricultural systems, but the dynamics and impact of these invasions in native forest ecosystems is largely unknown. The impacts of earthworm invasion are expected to be related to the size and species composition of the earthworm population because different species have dif- ferent habitat and feeding preferences. We identified four sugar maple dominated forests in north central Minnesota in the Chippewa National Forest with active earthworm invasion. In each site a sample grid of 45 points (30 150 m) 10 m apart in three parallel transects with 15 points each was established that spanned a visible leading edge of invasion. Over four years earthworm populations and forest floor thickness were sampled across all tran- sects, thus providing both a space-for-time assessment of decadal scale successional dy- namics and a four-year window into shorter time changes. We found a succession of earth- worm species across the visible leading edge due to different patterns of colonization by different earthworm species. Marked increases in space and time in earthworm biomass were associated with the development of discrete transition zones where forest floor thick- ness decreases to zero in as little as 75 m from areas that have forest floor layers up to 10 cm thick with advancement of the visible leading edge of up to 30 m in four years at three of the study sites. The epi-endogeic species Lumbricus rubellus led to the most rapid removal of forest floor material during initial invasion. Epigeic and epi-endogeic species of earth- worms may facilitate the establishment of other species of earthworms leading to the establishment of stable populations of endogeic and anecic species, which prevent recovery of the forest floor.
Effects of succinylation and dodecyl succinylation on bovine factor VIII/von willebrand factor complex

Abstract Blocking the ϵ-amino·groups of the lysine residues in the bovine VIII/vWf complex by succinylation and dodecyl succinylation resulted in the total loss of procoagulant activity. In contrast, the platelet aggregating activity was totally lost after succinylation, but only partially lost after dodecyl succinylation. The VIII R-Ag of modified complex remained active as shown by rocket immunoelectrophoresis and crossed immunoelectrophoresis. The net gain of negative charges by these two reactions resulted in an increase in mobility to the anode of their products upon electrophoresis. In the presence of SDS, no change in mobility was observed, indicating that no dissociation of subunits had occurred. These findings suggest that lysine residues are involved in the binding and/or active sites of the VIII/vWf complex and the hydrophobic 16-carbon chain introduced to this complex by dodecyl succinylation might play a stabilizing role in the platelet-von Willebrand factor interaction.
Influence of vitamin C supplementation on oxidative and salivary IgA changes following an ultramarathon

This randomized study measured the influence of vitamin C (N=15) compared to placebo (N=13) supplementation on oxidative and salivary immunoglobulin A (sIgA) changes in runners competing in an ultramarathon race. Seven days prior to the race, subjects ingested in randomized, double-blind fashion three 500-mg tablets of vitamin C or placebo each day. On race day, blood and saliva samples were collected 1 h pre-race, after 32 km of running, and then again immediately post-race. During the race, runners received 1 l/h carbohydrate beverages (60 g/l) with vitamin C (150 mg/l) or without in a double-blinded fashion. The runners also ingested two to three carbohydrate gel packs per hour (25 g each). Subjects in both groups ran a mean of 69 km (range 48–80 km) in 9.8 h (range 5–12 h) and maintained an intensity of approximately 75% maximal heart rate (HRmax) throughout the ultramarathon race. Plasma ascorbic acid was higher in the vitamin C compared to placebo group pre-race, and increased significantly in the vitamin C group during the race [post-race, 3.21 (0.29) and 1.28 (0.12) μg/100 μl, respectively, P<0.001]. No significant group or interaction effects were measured for lipid hydroperoxide and F2-isoprostane, but both oxidative measures rose significantly during the ultramarathon race. Saliva volume, sIgA concentration, sIgA secretion and sIgA:saliva protein ratio all decreased significantly (P<0.001) during the race, but the pattern of change in all saliva measures did not differ significantly between groups. No significant correlations were found between post-race plasma vitamin C, oxidative, and saliva measures, except for a positive correlation between post-race serum cortisol and serum vitamin C (r=0.50, P=0.006). These data indicate that vitamin C supplementation in carbohydrate-fed runners does not serve as a countermeasure to oxidative and sIgA changes during or following a competitive ultramarathon race.
Does Pygoderma Occur in North America

The phyllostomatid bat genus Pygoderma has frequently appeared in check lists of North and Middle American mammals. Thus Miller and Kellogg (1955) give as the range of Pygoderma bilabiatum “southern Brazil to southern Mexico.” Unable to find any recent Mexican or Central American records, I tried to find the earliest mention of the species occurring in Mexico. The species was first described by Wagner (1843) from Brazil as Phyllostoma bilabiatum . It was redescribed by Gray (1848), …
Seasonal changes in the fatty acid spectrum in the hibernating and non-hibernating ground squirrel Citellus tridecemlineatus.

Abstract 1. 1. The total lipid, water content and fatty acid spectrum of blood serum, liver and brown adipose tissue (BAT) were analyzed in hibernating and non-hibernating ground squirrels during an annual cycle. 2. 2. Fatty acids, chiefly oleic and linoleic acids, showed oscillatory cycles in the three tissues studied; these oscillations were less evident in hibernating animals. 3. 3. Brown adipose tissue contained the greatest amount of oleic acid in hibernating animals (60 per cent in March-April). In contrast to serum and liver, docosohexaenoic acid (22:6) was undetectable in BAT.
Smad4/DPC4: A barrier against tumor progression driven by RTK/Ras/Erk and Wnt/GSK3 signaling

The tumor suppressor Smad4/DPC4 is an essential transcription factor in the TGF-β pathway that was previously thought to function constitutively. We recently reported that Smad4 activity and stability are directly regulated by 2 major signaling pathways, RTK/MAPK and Wnt/GSK3. Here we examine the molecular, cellular, and potential therapeutic significance of these findings.
Information processing and some implications for more effective manpower programs

This brief paper will focus on the tremendous potential which now exists for the development of a more rational and effective technique for dealing with problems of manpower utilization. This topic should call for a far more detailed and sophisticated treatment than it is about to receive from me. For this, I must apologize, both to this audience and my own conscience. I feel, however, that the opportunity should be taken to outline to this particular audience the sort of information processing system which I feel must be developed if we are to have a more effective means for dealing with the growing manpower problem in the U.S.
Experimental search for color transparency at Jefferson Lab

Mapping the transition of the strong interaction from the hadronic degrees of freedom to the partonic degrees of freedom of quantum chromodynamics (QCD), is an important goal in intermediate energy nuclear and particle physics. One of the popular approaches used to study the transition between these two regions involves searching for the onset of various phenomena which are naturally predicted in QCD. One such phenomena is Color Transparency (CT), which refers to the suppression of final (and initial) state interactions of hadrons with the nuclear medium in exclusive processes at high momentum transfers. At Jefferson Lab the search for CT has focused on the (e,e’p) reaction. I will review the status of the experimental search for CT covering these experiments and others spanning over a decade. Some of the future experiments being planned for the 12 GeV upgrade of JLab will also be discussed.
Housing Market Dynamics Under Stochastic Growth: An Application to the Housing Market in Boulder, Colorado

Recent housing-market studies have modeled slow stock and price adjustment with some success. However, the empirical procedures used in these models break down if housing stocks or prices are driven by stochastic growth. In this paper I suggest an error-correction model for analyzing housing supply and demand under conditions of stochastic growth for a regional housing market. The model is applied to the housing market in Boulder, Colorado from 1981 through 1995—a period of rapid growth in housing values in the area. Long-run housing supply and demand are shown to be inelastic with respect to changes in the price of housing. The results indicate that developers respond more accurately to housing-market disequilibrium attributable to supply-side disturbances than to disturbances generated by changes in the demand for housing. On the other hand, price appreciation is driven primarily by demand disturbances.
Induction of dimethylnitrosamine demethylase activity in mouse liver by polychlorinated biphenyls and 3-methylcholanthrene

Abstract Hepatic dimethylnitrosamine (DMN) demethylase activity in male C57BL/6 mice, assayed with 1 or 5 mM DMN and expressed per g liver, increased after i.p. treatment with Aroclor 1254 [polychlorinated biphenyls (PCBS), 500 mg/kg, 96 hr before assay], compared with parallel oil-injected controls. This increase was of statistical significance when either the postmitochondrial supernatant fraction (sup) or isolated microsomes were assayed. The induction appeared larger with 5 mM DMN as substrate (about 180 per cent) than with 1 mM DMN (about 65 per cent). PCBs also induced sup DMN (5 mM) demethylase activity in (C57BL/6 × BALB/c)F 1 and Swiss-Webster mice. 3-Methyl-cholanthrene exposure (80 mg/kg, 48 hr) resulted in a small but significant increase in sup hepatic DMN (5 mM) demethylase activity in C57BL/6 and F 1 mice. Isolated microsomes from C57BL/6 livers exhibited only 40–60 per cent of the DMN (1 or 5 mM) demethylase activity present in the corresponding sup; such preparations may not give an accurate indication of in vivo activity. Inclusion of the lipid layer with the sup resulted in a significant increase in DMN (5 mM) demethylase activity in Aroclor-induced, but not in control, C57BL/6 mouse livers. The number of cells per unit area of liver, determined microscopically after treatment of C57BL/6 mice with PCBs, decreased slightly (15 per cent) but significantly compared with controls. Thus, enzyme activity per g liver represents a conservative approximation of activity per cell, which is the parameter that should be measured for demonstration of induction or repression and for evaluation of potential toxic or carcinogenic effects.
Organization and Morphology of Thalamocortical Neurons of Mouse Ventral Lateral Thalamus

The ventral lateral nucleus of the thalamus (VL) serves as a central integrative center for motor control, receiving inputs from the cerebellum, striatum, and cortex and projecting to the primary motor cortex. We aimed to determine the somatotopy and morphological features of the thalamocortical neurons within mouse VL. Retrograde tracing studies revealed that whisker-related VL neurons were found relatively anterior and medial to those labeled following injection of retrograde tracer into hindpaw motor areas. Simultaneous injections of fluorescent microspheres in both cortical regions did not result in double-labeled neurons in VL. Quantitative analysis of dendritic and somatic morphologies did not reveal any differences between hindpaw and whisker thalamocortical neurons within VL. The morphology of the thalamocortical neurons within mouse VL is similar to those in other mammals and suggests that mouse can be used as a model system for studying thalamocortical transformations within the motor system as well as plasticity following sensory deprivation or enrichment.
Embolectomy-Induced Pseudoaneurysm Causing a Brachial Plexopathy A Case Report

Pseudoaneurysm is a rare cause of compressive brachial plexopathy. The authors describe a thirty-seven-year-old man with hypertension and renal disease who presented with a painful and weak left upper extremity. Examination revealed a cool extremity with absent pulses, profound weakness, and diminished sensation and reflexes restricted to the left upper limb. During emergency exploration, a thromboembolus was extracted from the subclavian artery by means of a brachial artery entrance site. A postoperative arteri ogram revealed persistent subclavian artery occlusion. On reexploration, a second throm boembolus was removed. Postoperatively, the patient regained pulses, and over several days his left upper limb strength improved.On reevaluation several weeks later, the patient complained of greater weakness in the left arm, forearm, and hand, which was confirmed on physical examination. Nerve conduction studies and an electromyogram were interpreted as consistent with a severe left brachial plexopathy. Magnet...
Optimal Design of Linear and Nonlinear Vibration Absorbers for Damped Systems

Nonlinear programming techniques are applied to obtain optimal tuning and damping parameters for dynamic absorbers. The optimization has been carried out for damped as well as undamped primary systems. It is found that optimal tuning parameters, obtained with the goal of minimizing the main mass maximum displacement, undergo small changes as damping is introduced into the main system. The use of other objective functions, such as minimizing maximum velocity, or mean-squared motion to white noise excitation lead to more significant changes in optimal parameter values. It is shown, on the basis of approximate solutions to the nonlinear absorber problem, that only small improvements in steady state response are obtained using hardening or softening coupling springs.
Transcriptional responses of the nerve agent-sensitive brain regions amygdala, hippocampus, piriform cortex, septum, and thalamus following exposure to the organophosphonate anticholinesterase sarin

Background Although the acute toxicity of organophosphorus nerve agents is known to result from acetylcholinesterase inhibition, the molecular mechanisms involved in the development of neuropathology following nerve agent-induced seizure are not well understood. To help determine these pathways, we previously used microarray analysis to identify gene expression changes in the rat piriform cortex, a region of the rat brain sensitive to nerve agent exposure, over a 24-h time period following sarin-induced seizure. We found significant differences in gene expression profiles and identified secondary responses that potentially lead to brain injury and cell death. To advance our understanding of the molecular mechanisms involved in sarin-induced toxicity, we analyzed gene expression changes in four other areas of the rat brain known to be affected by nerve agent-induced seizure (amygdala, hippocampus, septum, and thalamus).