cssi/SciSciGPT-SciSciNet huggingface dataset:
Locomotion elicited by MK801 in developing and adult rats: temporal, environmental, and gender effects.

Abstract The effects of environmental novelty on locomotion elicited by an N-methyl- d -aspartate (NMDA) receptor antagonist, (+)MK-801 hydrogen maleate [(5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine], were investigated. Male and female rats aged 10, 20, 30 or 54–68 days were injected s.c. with MK801 and placed in activity monitors either immediately (no-delay) or after a 60 min delay (delay). In the no-delay condition, MK801 induced an inverse U-shaped dose–response effect on locomotion; peak activation occurred with 0.1 mg/kg and ataxia occurred with higher doses. The introduction of a novel environment 60 min after drug injection shifted the dose–effect function of MK801 to the left; i.e., in rats 20 days of age and older, the activity induced by 0.1 mg/kg MK801 was potentiated in the delay condition. For the 0.5 mg/kg dose, 20-day-olds showed activation in the no-delay condition but ataxia in the delay condition. This dose induced ataxia followed by activation in 30-day-olds and adult males or ataxia in adult females, regardless of delay condition. Age-, gender-, and novelty-dependent variations in MK801-induced locomotion may reflect differences in limbic–motor circuitry.
Production of superoxide anion during the oxidation of hemoglobin by menadione

Abstract Menadione in the presence of oxyhemoglobin will accelerate the formation of methomoglobin and result in the generation of superoxide anion. Menadione appears to oxidize slowly ferrohemoglobin to ferrihemoglobin, while forming menadione semiquinone in the process. Menadione semiquinone is known to react with molecular oxygen to yield superoxide anion. The superoxide anion appears to be the source of hydrogen peroxide which accounts for most of the observed methemoglobin formation when hemoglobin is reacted with menadione.
Na/K pump current and [Na](i) in rabbit ventricular myocytes: local [Na](i) depletion and Na buffering.

Na/K pump current (Ipump) and intracellular Na concentration ([Na]i) were measured simultaneously in voltage-clamped rabbit ventricular myocytes, under conditions where [Na]i is controlled mainly by membrane transport. Upon abrupt pump reactivation (after 10–12 min blockade), Ipump decays in two phases. Initially, Ipump declines with little [Na]i change, whereas the second phase is accompanied by [Na]i decline. Initial Ipump sag was still present at external [K] = 15 mM, but prevented by [Na]i ∼ 100 mM. Initial Ipump sag might be explained by subsarcolemmal [Na]i ([Na]SL) depletion produced by rapid Na extrusion and Ipump. Brief episodes of pump blockade allowed [Na]SL repletion, since peak postblockade Ipump exceeded Ipump at the end of previous activation (without appreciably altered global [Na]i). The apparent Km for [Na]i was higher for continuous Ipump activation than peak Ipump (14.1 ± 0.2 vs. 11.2 ± 0.2 mM), whereas that based on d[Na]i/dt matched peak Ipump (11.6 ± 0.3 mM). [Na]SL depletion (vs. [Na]i) could be as high as 3 mM for [Na]i ∼ 18–20 mM. A simple diffusion model indicates that such [Na]SL depletion requires a Na diffusion coefficient 103- to 104-fold below that expected in bulk cytoplasm (although this could be subsarcolemmal only). Ipump integrals and [Na]i decline were used to estimate intracellular Na buffering, which is slight (1.39 ± 0.09).
Cytogenetic effects of hycanthone in the rat.

Abstract Hycanthone methanesulfonate (HCT), a new drug used for the treatment of schistosomiasis, was examined for its ability to produce chromosomal abnormalities in rat bone marrow cells. Rats were given intraperitoneal injections of HCT at 40, 80, or 100 mg/kg and were killed at 6, 24, or 48 h. All levels produced a significant increase cells with abnormalities at all three time periods. There was a significant linear relationship between arithmetic dose and the proportion of cells affected. Based on two of the three experiments peformed, assuming the same slope holds in the vicinity of 0, the upper 95% confidence limits on the expected risk at level of 0.5] mg/kg would be a 0.055% increase in affected cells above control values.
Counseling Issues for Adult Women in Career Transition

This article addresses current psychosocial issues facing women in career transition and the implications of those issues for career counselors. Specifically, psychosocial developmental trajectories, the roles of family and relationships, the importance of underlying physical and mental health issues, and sociocultural and contextual stressors are relevant for women in the midst of career change. The author discusses how career counselors can prepare for this complexity and addresses clients' current economic and social milieus. A checklist is provided to aid the career counselor in addressing the multiple issues that a new client brings to the 1st counseling encounter.
Mechanochemical approaches to self-regulating insulin pump design

Abstract Wearable and implantable insulin delivery devices have been proposed by many groups to replace periodic subcutaneous insulin injection. The rationale behind this work lies in the lack of correspondence between insulin and glucose disposition resulting from subcutaneous administration compared with that occurring after pancreatic insulin release. We briefly review features of insulin and glucose disposition processes that impact the design of artificial insulin delivery systems, enabling advantages and disadvantages of currently pursued strategies (electromechanical, biochemical, chemical, mechanochemical) to be identified. We also propose two implantable self-regulating insulin pumps whose action depends on the expansion and contraction of certain pH-sensitive hydrogel membranes that respond to changes in glucose concentration via enzymatic conversion of glucose to gluconic acid. It is shown that the dynamics of pH-sensitive volume changes favor one pump design, based on direct conversion of changes in glucose concentration to mechanical force, over the other, which is an osmotic pump whose semipermeable membrane's permeability to water is sensitive to glucose concentration.
Matrix isolation studies of reactive intermediate complexes

Cas particulier des composes d'addition formes entre acides et bases de Lewis, par exemple SiF 4 •NH 3
Pharmacokinetics and bioavailability of chloramphenicol in normal and febrile goats.

The effect of induced fever on the plasma concentrations and disposition kinetics of chloramphenicol (CHPC) was studied in adult goats. Fever was induced and maintained for 12 h by injecting Escherichia coli endotoxin (0.1 microgram/kg, i.v.) and repeating it at half the dose (0.05 microgram/kg) 8 h later. Pharmacokinetics of CHPC was studied in both normal (n = 6) and febrile (n = 6) animals following intravenous administration of CHPC Na-succinate (25 mg/kg). Intramuscular bioavailability of the drug was also investigated in both normal and febrile animals. Pharmacokinetics of CHPC following intravenous administration could be described by a two-compartment open model in both normal and febrile animals. In normal animals the half-life of CHPC was 73.0 +/- 4.95 min and the volume of distribution was 2.217 +/- 0.24 l/kg. These and other pharmacokinetic parameters did not differ significantly (P less than 0.05) between normal and febrile animals, except for Cop and A. Absorption of CHPC following intramuscular administration was good as indicated by its high bioavailability in both normal (83.34%) and febrile (81.98%) animals. Volume of distribution is usually expected to change when the febrile state is induced. Lack of such an effect in the present study could be due to high individual variation, or to the fact that CHPC already has a relatively large volume of distribution, which is less likely to be altered by a febrile state of short duration.
Measuring photon pathlengths by quasielastic light scattering in a multiply scattering medium

To gain insight into the migration of photons in optically dense heterogeneously structured media, scattering models have been developed which consist of polystyrene latex particles suspended in solutions containing varying amounts of absorptive dye. The amount and distribution of the dye affect the mean pathlength of emergent photons, the latter being proportional to , the average number of collisions of photons with moving scatterers. The quantity has been determined by cumulant analysis of the measured time autocorrelation function for photons which are injected and detected with a pair of fiber optodes positioned at the surface of the scattering medium. In agreement with theoretical predictions, is found to vary linearly with the spacing between the optodes if the medium is homogeneous. Moreover, when the scattering medium is composed of layers whose optical absorptions differ, the detected autocorrelation functions indicate that the photons which successfully traverse the medium move along paths which minimize the absorption probability.
Electrochemical analysis of lithiated graphite anodes

Theoretical calculations are compared with well-controlled experiments conducted on a porous, graphite-based, lithiated-carbon electrode. The interpretation of the electrode behavior is facilitated by the use of a reference electrode in a cell that maintains a substantially uniform current distribution. A solvent-casting procedure for constructing graphite anodes, employing a hydrocarbon binder is implemented. Nonlinear diffusion of lithium intercalate within the host carbon particles is considered; previously published concentration-dependent diffusion-coefficient data are employed for the lithium intercalate species. Other important resistances result from ionic diffusion and migration within the solvent phase, interfacial reaction at the surface of the carbon particles, and electron transport within the solid phase. Calculations are used to assess the impact of particle shape and the nature of the carbon precursor. The overall analysis indicates that interfacial resistance plays a dominant role in limiting the available capacity at high rates of current passage. © 2003 The Electrochemical Society. All rights reserved.
Reversed and Anomalous Doppler Effects in Photonic Crystals and other Time-dependent Periodic Media

We predict that reversed and anomalous non-relativistic Doppler shifts can be observed under some circumstances when light reflects from a shock wave front propagating through a photonic crystal, or material with a periodic modulation of the dielectric. This theoretical prediction is generalizable and applies to wave-like excitations in a variety of periodic media. An experimental observation of this effect has recently been made (Seddon, N. and Bearpark, T. Science, 302 (2003) 1537) and we provide a brief discussion of this experiment.
Stocking Strategies and an Investment Analysis for Producing Penaeus setiferus as a Live Bait‐Shrimp on the Texas Gulf Coast

An economic and investment analysis was performed to determine the viability of bait-shrimp farming in Texas. A single pond analysis producing 5–5.5g shrimp always had higher returns above selected cost (RASC) than producing 4–4.5g shrimp. Stocking 0.01g shrimp had a higher RASC than stocking 0.25g, 0.50g or 0.75g shrimp. In the 20 pond analysis, which accounted for marketing considerations, stocking 0.25g shrimp had the highest RASC. The investment analysis, assuming average management, was declared bankrupt by the end of the fifth year. Under “excellent” management the internal rate of return was only 11.7%. It is unlikely that bait-shrimp farming will become a viable industry in Texas in the near future.
Constructing the Self

Constructing the Self Valerie Gray Hardcastle Amsterdam: John Benjamins, 2008 186 pages, ISBN: 9027252092 (hbk); $149.00 The idea that we construct our selves through a kind of personal storytellin...
Towards Lightweight and Swift Storage Resource Management in Big Data Cloud Era

Workload IO behavior in modern data centers is fluctuating and unpredictable due to the rapidly adopted, public cloud environment. Nevertheless, existing storage resource management systems, such as VMware SDRS, are incapable of performing real time policy-based storage management due to the high cost of migrating large size virtual disks. Hence, the traditional storage management schemes become ineffective due to the lack of quick response to the frequent IO bursts and the inaccurate storage latency prediction in the light of a highly fluctuating environment. To address the aforementioned issues, we propose LightSRM, which can work properly in a time-variant cloud environment. To mitigate the storage migration cost, we leverage copy-on-write/read snapshots to redirect the IO requests without moving the virtual disk. To support snapshots in storage management, we also build a performance model specifically for snapshots. We employ exponentially weighted moving average with adjustable sliding window to provide quick and accurate performance prediction. Furthermore, we propose a hybrid management scheme, which can dynamically choose either snapshot or migration for fastest performance tuning. We build our prototype in a QEMU/KVM based virtualized environment. Our empirical evaluation results show that snapshot can redirect IO requests in a faster manner than migration can do when the virtual disk size is large. Besides, snapshot method has less disk performance impact on the applications. By employing hybrid snapshot/migration method, LightSRM yields less overall latency, better load balance, and less IO traffic overhead.
Biochemical Failure Rates are Modality and Definition Dependent: A Matched Comparison of Iodine-125 Permanent Prostate Brachytherapy Monotherapy and Radical Retropubic Prostatectomy Patients

Materials/Methods: From 1/98-12/03, a total of 3,521 RRP and 425 PPB pts were treated at our institution. Pts receiving androgen deprivation (ADT) pre-therapy or adjuvantly ( 90 days) were excluded. A previously described algorithm was applied to the RRP cohort to match groups (grp). Nine BFDs were used to compare the biochemical relapse free survival (bRFS) rates. These included: pts with PSA above 0.2, 0.4, and 1.0 ng/ml 1 yr post-therapy (BFDs 1,2 and 3), pts with a single PSA above nadir by 0.5 or 1.0ng/ml, BFDs (BFDs 4 and 5), pts with 3 PSA rises above post-therapy nadir by any amount (BFD 6), pts with 2 or 3 rising PSAs above nadir with each rise 0.5ng/ml (BFDs 7 and 8), or 3 rising PSAs above nadir by any amount, back-dated to the date of the first rising PSA (BFD 9). Subsequent ADT was considered a failure. All PPB pts had post-implant CT-based dosimetry with yearly D90 and V100 medians ranging from 149 to 162Gy and 93 to 97% respectively.
Slip propagation in epitaxial Mo (011) studied by low-energy electron microscopy

We report observations of slip processes in epitaxial films of Mo (011) grown on sapphire by molecular beam epitaxy. Low-energy electron microscopy is employed to follow the time evolution of the screw dislocation, the interfacial dislocation, and the surface step edge structure through which the slip takes place. Under certain conditions the dislocation system is observed to trap briefly as it meets successive surface steps.
Combined laparoscopic and endoscopic management of cholelithiasis and choledocholithiasis.

With the advent of laparoscopic cholecystectomy, optimal management of common duct stones remains controversial. Seven hundred six patients underwent laparoscopic cholecystectomy in our institution from January 1990 through January 1992. From this group of patients, 50 were identified as having clinical or radiographic evidence of common duct stones. Thirty-one patients demonstrated preoperative risk factors for common duct stones and underwent preoperative endoscopic retrograde cholangiopancreatography (ERCP). The risk factors included jaundice (19%), pancreatitis (23%), elevated liver function tests (52%), and ultrasound evidence of choledocholithiasis (6%). Preoperative ERCP was performed in 94% of patients. There were two failures due to periampullary diverticula. Common duct stones were identified in 18 patients (62%) and successfully removed by endoscopic sphincterotomy in all of these patients. Nineteen patients were found to have unsuspected common duct stones on intraoperative cholangiography. Eighteen patients (95%) underwent successful ERCP and endoscopic sphincterotomy with stone extraction. Overall, major morbidity was 2% and included one patient who experienced endoscopic sphincterotomy-related bleeding that required surgical sphincteroplasty. The three endoscopic failures were managed by open common duct exploration, laparoscopic duct exploration, and combined laparoscopic and open common duct exploration. We conclude that combined laparoscopic and endoscopic therapy is a viable option for the management of cholelithiasis with choledocholithiasis.
Analysis and simulation of propagule dispersal and salinity intrusion from storm surge on the movement of a marsh–mangrove ecotone in South Florida

Coastal mangrove–freshwater marsh ecotones of the Everglades represent transitions between marine salt-tolerant halophytic and freshwater salt-intolerant glycophytic communities. It is hypothesized here that a self-reinforcing feedback, termed a “vegetation switch,” between vegetation and soil salinity, helps maintain the sharp mangrove–marsh ecotone. A general theoretical implication of the switch mechanism is that the ecotone will be stable to small disturbances but vulnerable to rapid regime shifts from large disturbances, such as storm surges, which could cause large spatial displacements of the ecotone. We develop a simulation model to describe the vegetation switch mechanism. The model couples vegetation dynamics and hydrologic processes. The key factors in the model are the amount of salt-water intrusion into the freshwater wetland and the passive transport of mangrove (e.g., Rhizophora mangle) viviparous seeds or propagules. Results from the model simulations indicate that a regime shift from freshwater marsh to mangroves is sensitive to the duration of soil salinization through storm surge overwash and to the density of mangrove propagules or seedlings transported into the marsh. We parameterized our model with empirical hydrologic data collected from the period 2000–2010 at one mangrove–marsh ecotone location in southwestern Florida to forecast possible long-term effects of Hurricane Wilma (24 October 2005). The model indicated that the effects of that storm surge were too weak to trigger a regime shift at the sites we studied, 50 km south of the Hurricane Wilma eyewall, but simulations with more severe artificial disturbances were capable of causing substantial regime shifts.
The Contribution of LTR Retrotransposon Sequences to Gene Evolution in Mus musculus

Approximately 1.5% of mouse genes (Mus musculus) contain long terminal repeat retrotransposon sequences (LRS). Consistent with earlier findings in Caenorhabditis elegans, Drosophila melanogaster, and Homo sapiens, LRS are more likely to be associated with newly evolved genes. Evidence is presented that LRS are often recruited as novel exons or as spliced additions to existing exons. These novel gene configurations may be expressed initially as alternative transcripts providing an opportunity for the evolution of new gene function.
PREHISTOLOGIC CHANGES IN THE REJECTION MECHANISM OF BONE TRANSPLANTS.

Summary In rabbits irreversible changes occur in the surviving cells of homogenous transplants of bone about six days following transplantation.
Public sector union democracy: A comparative analysis

A congressional subcommittee held “union democracy” hearings in 1998 and 1999 to debate the impact and effectiveness of the union-democracy protections provided by the Land rum-Griffin Act which provides union members in the private sector and U.S. Postal Service certain democratic rights and protections. What was not resolved at that hearing was whether state sector or public employee union members should also enjoy the same democracy protections. We survey the existing 28 state sector collective bargaining laws and find that the majority of state legislation falls considerably short of the protections provided by the Labor Management Reporting and Disclosure Act. Moreover the consequences of limited state-enacted union-democracy protections are discussed and assessed to determine whether LMRDA jurisdiction should also cover public sector union members.
A Controlled Experiment in Feeding Wheat Germ Oil as a Supplement to the Normal Ration of Bulls Used for Artificial Insemination

Summary Two comparable groups of 10 bulls each were selected. Both were fed a practical ration made up of common, natural feeds which supplied plenty of vitamin E for normal reproduction of rats. To determine whether or not additional vitamin E in the form of solvent process wheat germ oil would benefit the reproductive performance of bulls used extensively for artificial insemination, each of the bulls in one group received one ounce daily of the wheat germ oil during an experimental period of one year. Over 1,250 semen samples were collected from the 20 bulls, and over 8,200 cows were artificially inseminated during the experiment. A comparison of the results from the two groups warrants the following statements: The feeding of one ounce daily of solvent process wheat germ oil in addition to the normal ration did not: 1. Increase the volume of semen produced by the bulls; 2. Increase the spermatozoa concentration in the semen; 3. Improve the motility of the spermatozoa; 4. Shorten the time required for service; 5. Decrease the number of semen ejaculates which were discarded as being of too poor quality for use in artificial insemination; 6. Improve the fertility of the bulls to which it was fed; 7. Nor prevent two bulls from decreasing in fertility to such low levels as to force their withdrawal from use in artificial insemination. A study of the seasonal effects showed a highly significant decrease in percentage of motile spermatozoa during the early spring months and a highly significant difference between months in spermatozoa count. The lowest average count was found in August, but there was no significant difference in fertility of the bulls from month to month.
Neuroendocrine correlates of the type A behavior pattern: a review and new hypotheses.

Various studies have tried to identify the possible neuroendocrine correlates of the action/emotion complex defined as Type A behavior pattern. Type A subjects have been observed quite consistently to respond to laboratory stressors with a greater sympathetic nervous system response than Type B subjects. There also seems to be a trend towards a hyperactivity of the hypothalamic-pituitary-adrenocortical axis in Type A individuals. The clinical relevance of these findings lies in the fact that there is an increasing clinical and laboratory evidence of a pathogenic role of catecholamines in coronary artery disease (CAD) and that some of these neuroendocrine correlates might actually be the mediators of the risk of CAD conferred by the Type A behavior pattern. We hypothesize that dehydroepiandrosterone-sulfate (DHEA-S), an adrenal weak androgen, is inversely correlated with the degree of Type A behavior pattern and this hypothesis seems to be confirmed by the results of a preliminary investigation that we hav...
Two Plant Bacteria, S. meliloti and Ca. Liberibacter asiaticus, Share Functional znuABC Homologues That Encode for a High Affinity Zinc Uptake System

The Znu system, encoded for by znuABC, can be found in multiple genera of bacteria and has been shown to be responsible for the import of zinc under low zinc conditions. Although this high-affinity uptake system is known to be important for both growth and/or pathogenesis in bacteria, it has not been functionally characterized in a plant-associated bacterium. A single homologue of this system has been identified in the plant endosymbiont, Sinorhizobium meliloti, while two homologous systems were found in the destructive citrus pathogen, Candidatus Liberibacter asiaticus. To understand the role of these protein homologues, a complementation assay was devised allowing the individual genes that comprise the system to be assayed independently for their ability to reinstate a partially-inactivated Znu system. Results from the assays have demonstrated that although all of the genes from S. meliloti were able to restore activity, only one of the two Ca. Liberibacter asiaticus encoded gene clusters contained genes that were able to functionally complement the system. Additional analysis of the gene clusters reveals that distinct modes of regulation may also exist between the Ca. Liberibacter asiaticus and S. meliloti import systems despite the intracellular-plant niche common to both of these bacteria.
Nonspherical ZnS colloidal building blocks for three-dimensional photonic crystals.

Abstract The asymmetry introduced by a complex or nonspherical basis promotes photonic band gap formation in three-dimensional photonic crystals. However, relatively few techniques have been demonstrated to produce uniform nonspherical colloids for use as photonic crystal bases. Here we expand the menu of basis types with high refractive index by preparing nonspherical zinc sulfide colloids of uniform size and shape. Dimers, trimers, and planar tetramers were precipitated from aqueous solution by the thermal decomposition of thioacetamide in the presence of zinc nitrate, manganese nitrate, and nitric acid. The well-defined morphological types were obtained from suspensions aged for 4–6 h at 26–32 °C and then for 20–35 min at 85 °C. Stereological techniques were used to analyze SEM images and determine the percentage of each particle class. For example, the quantitative characterization of a particle population prepared at 29 °C for 6 h and 85 °C for 22 min had the composition 59±3% spheres, 31±2% dimers, 7±1% trimers, 0.4±0.2% tetramers, and 2.5±0.8% complex clusters (encompasses all other varieties of shape). X-ray diffraction and X-ray photoelectron spectroscopy confirmed the zinc blend crystal structure and the stoichiometric composition of the particles. The refractive index was estimated as 2.25 (413 nm)–2.09 (709 nm) by fitting experimental absorption spectra to curves derived from Mie scattering calculations. This indicated an average porosity ∼24%. Such colloids offer the potential to form diamond-like lattices with large, stable photonic band gaps.
Immunohistochemical Characterization of Spontaneous Sertoli Cell Clusters in the Seminiferous Tubules of C57BL/6J Mice

Cell clusters were observed in the seminiferous tubules of C57BL/6J mice as a spontaneous lesion in a 2-week toxicity study, and they were demonstrated to be basically composed of Sertoli cells by immunohistochemistry for claudin-11 and GATA-4 (GATA-binding protein 4), which are both Sertoli cell markers. The clusters were composed of about 5 to 50 cells, which had eosinophilic and occasionally vacuolated cytoplasm with an unclear cell boundary. The cell clusters involved some sperm. No mitotic figures were observed and no immunoreactivity for proliferating cell nuclear antigen (PCNA) was detected in the clusters. In most cases, the cell clusters were observed in seminiferous tubules that also showed degenerative changes. In rare instances, cell aggregates immunohistochemically positive for claudin-11 were observed in the lumen of the epididymis, suggesting that some of the Sertoli cell clusters were sloughed off from the seminiferous epithelium into the epididymal ducts. To our knowledge, this is the first report of Sertoli cell clusters in any animal species except for transgenic or surgically altered animals.
Subcutaneous fat necrosis of the newborn: light, ultrastructural and histochemical microscopic studies

Multiple subcutaneous plaques and nodules appeared on the back and the dorsal proximal area of the extremities of a 9-day-old male infant after a complicated prenatal period necessitating cesarean section. The clinical and histological features were diagnostic of subcutaneous fat necrosis of the newborn. Light microscopy revealed adipocyte necrosis, a lymphohistiocytic infiltrate, and needle-shaped clefts within adipocytes and macrophages. Ultrastructurally, there were aggregations of electron-lucent spaces in the form of spindles and needles arranged in parallel within the altered adipocytes; macrophages surrounded these cells or their fragments and invaded the fat lobules. Enzyme histochemical staining, not previously reported in the literature, showed that acid phosphatase, leucine aminopeptidase, and indoxyl and non-specific esterases were present in the areas of fat necrosis.
System management in the BlueGene/L supercomputer

The BlueGene/L supercomputer will use system-on-a-chip integration and a highly scalable cellular architecture to deliver 360 teraflops of peak computing power. With 65536 compute nodes, BlueGene/L represents a new level of scalability for parallel systems. As such, it is natural for many scalability challenges to arise. In this paper, we discuss system management and control, including machine booting, software installation, user account management, system monitoring, and job execution. We address the issue of scalability by organizing the system hierarchically. The 65536 compute nodes are organized in 1024 clusters of 64 compute nodes each, called processing sets. Each processing set is under control of a 65th node, called an I/O node. The 1024 processing sets can then be managed to a great extent as a regular Linux cluster, of which there are several successful examples. Regular cluster management is complemented by BlueGene/L specific services, performed by a service node over a separate control network. Our software development and experiments have been conducted so far using an architecturally accurate simulator of BlueGene/L, and we are gearing up to test real prototypes in 2003.
Insights into the suppressor of T-cell receptor (TCR) signaling-1 (Sts-1)-mediated regulation of TCR signaling through the use of novel substrate-trapping Sts-1 phosphatase variants

High affinity substrate-trapping protein tyrosine phosphatases have been widely used both to investigate the endogenous targets of many phosphatases and to address questions of substrate specificity. Herein, we extend the concept of a substrate-trapping phosphatase to include an enzyme of the histidine phosphatase superfamily. This is the first description of substrate-trapping technology applied to a member of the histidine phosphatase family. The phosphatase suppressor of T-cell receptor signaling (Sts)-1 has recently been reported to negatively regulate signaling downstream of the T-cell receptor. We generated high-affinity substrate-trapping variants of Sts-1 by mutagenesis of key active site residues within the phosphatase catalytic domain. Mutation of both the nucleophilic His380 and the general acid Glu490 yielded Sts-1 enzymes that were catalytically inactive but showed high affinity for an important tyrosine kinase in T cells that Sts-1 is known to regulate, Zap-70. Sts-1 substrate-trapping mutants isolated tyrosine-phosphorylated Zap-70 from lysates of activated T cells, validating Zap-70 as a possible substrate for Sts-1 and highlighting the efficacy of the mutants as substrate-trapping agents. Inhibition of the Zap-70 interaction by vanadate suggests that the substrate-trapping effect occurred via the Sts-1 phosphatase active site. Finally, overexpression of Sts-1 substrate-trapping mutants in T cells blocked T-cell receptor signaling, confirming the inhibitory effect of Sts-1 on Zap-70.
ETHICS AND OBSERVATION: DEWEY, THOREAU, AND HARMAN

: In 1929, John Dewey said that “the problem of restoring integration and cooperation between man's beliefs about the world in which he lives and his beliefs about the values and purposes that should direct his conduct is the deepest problem of human life.” Using this as its theme, this article begins with an examination of Gilbert Harman's reasons for denying the existence of moral facts. It then presents an alternative account of the relationship between science and ethics, making use of the writings of Dewey and Henry David Thoreau. For both Dewey and Thoreau, the dichotomy between a scientific approach to the world and an ethical approach to the world is a false one. The article explores the reasons for believing that the dichotomy is a false one, agreeing with Thoreau that there “is no exclusively moral law—there is no exclusively physical law.”
Morphological pseudo bandpass image decompositions

A morphological bandpass filter would, ideally, strictly limit the sizes of all features in an image to lie between the sizes of two similarly shaped but differently scaled structuring elements. A morphological bandpass decomposition of an image would be a disjoint set of morphological bandpass images with features of increasing size such that the set sums to the original image. Such strict bandpass limitations in size are not possible in general for arbitrary structuring element families. Hence, a true bandpass decomposition is not generally possible. Pseudo bandpass decompositions, in which intraband size limitations are relaxed, are possible and can be useful image analysis tools. Four pseudo bandpass image decompositions are described, one of which, the opening spectrum, is relatively well known and three of which are new. They are a decomposition derived from iteration of the top-hat transform, a morphological reconstruction of a Euclidean (quasi) granulometry, and a reconstruction of the opening spectrum. Properties of the opening spectrum and the top-hat transform are reviewed. The tophat spectrum is defined, some of its properties are deduced, and it is compared to the opening spectrum. The reconstruction-based decompositions are defined and compared to the others. Comparative examples are given and a practical use described.
Global information technology: issues and opportunities

To use information technology effectively as a competitive weapon, a company must identify the critical strategic issues which it intends to address. This paper presents several hypotheses about the critical issues facing globally-competing companies. Using these hypotheses, alternative directions for information systems strategies are assessed. This assessment leads to the conclusion that systems designed to support teams working on critical tasks will have the greatest strategic return to a globally-competing company. >
Limits of applicability of the advection-dispersion model in aquifers containing connected high-conductivity channels

[1] The macrodispersion model from stochastic transport theory is demonstrated to be of limited utility when applied to heterogeneous aquifer systems containing narrow connected pathways. This is so even when contrasts in hydraulic conductivity (K) are small and variance in ln K is less than 0.10. We evaluated how well an advection-dispersion model (ADM) could be used to represent solute plumes transported through mildly heterogeneous three-dimensional (3-D) systems characterized by a well-connected dendritic network of 10 cm wide high-K channels. Each high-K channel network was generated using an invasion percolation algorithm and consisted of ∼10% by volume high-K regions. Contrasts in K between the channels and matrix were varied systematically from 2:1 to 30:1, corresponding to ln K values ranging from 0.04 to 1.05. Simulations involved numerical models with 3-D decimeter discretization, and each model contained 2–4 million active cells. Transport through each channel network considered only the processes of advection and molecular diffusion. In every case, the temporal change in the second spatial moment of concentrations was linear, with R2 values ranging from 0.97 to 0.99. The third spatial moment, or alternatively, the skewness coefficient values, indicated significant tailing downstream of the plume center. For each case, a corresponding ADM was used to simulate transport through the system. The corresponding ADM employed the effective mean hydraulic conductivity that reproduced the total discharge through the channel network system under an identical ambient gradient. Dispersivity values used in the ADM were obtained from the temporal change in the second spatial moments of concentrations for the plumes in the channel network systems and ranged from 0.014 m to 0.85 m. The results indicate that as the conductivity contrast between the channels and matrix increased, the simulated plumes in the channel network system became more and more asymmetric, with little solute dispersed upstream of the plume center and extensive downstream spreading of low concentrations. Distinctly different spreading was found upstream versus downstream of the plume center. The ADM failed to capture this asymmetry. Comparison of each plume in the channel network system with the corresponding plume produced using the corresponding ADM showed a maximum correlation of only 0.64 and a minimum fractional error of 0.29 for cases in which the log K variance was ∼0.20 (ln K variance was ∼1.0). At early times the correlations were as low as 0.40. The greatest correlation occurred at late times and for cases in which a wide source was considered.
Glucose, insulin, and insulin resistance in normal-weight, overweight and obese children with obstructive sleep apnea.

Summary Background Obstructive sleep apnea (OSA) is associated with components of metabolic syndrome. Both body weight and OSA independently influence metabolic measurements. The goal of this study was to determine whether OSA in normal-weight, overweight or obese children, compared to matched control groups, was associated with increased levels of glucose, insulin and insulin resistance (IR). Methods Age- and gender-specific body mass index (BMI) percentiles were determined and used to categorize subjects into normal-weight (BMI Results Glucose, insulin, and HOMA-IR in OSA and matched control groups were not significantly different for normal-weight, overweight and obese subjects. The ODI was significantly associated with elevated levels of glucose and HOMA-IR after adjustment for age, gender, race, and BMI Z -score. Conclusions IR levels between OSA and control for both normal-weight, overweight and obese subjects were not significantly different. The ODI was associated with increased IR in children with OSA. OSA-induced hypoxic events during sleep may be a potential mechanism of increased IR in children with OSA, independent of body weight.
Levels of analysis and social class differences in language.

Previous studies have demonstrated that certain differences in speech behaviour can be related to the social characteristics of speakers. However, these studies have not explicitly examined the effect of level of linguistic analysis on correlations observed between language variables and status variables. Three levels of analysis of a linguistic construction were selected for study: grammatical form, lexical choice and use of a predication type. The corpus was the speech of forty-eight dyads of children (male, female; low, middle socio-economic status; Negro, white) performing three problem-solving tasks. The grammatical form of the construction differentiated between social groups, sexes and races. Lexical choice within the construction differentiated between social groups. Use of the predication type however, seemed to depend primarily on the task itself. The findings demonstrate that status differences in speech behaviour at one level of linguistic analysis cannot be taken as evidence that similar stat...
Avidity, Potency, and Cross-Reactivity of Monoclonal Antibodies to Pneumococcal Capsular Polysaccharide Serotype 6B

Many pneumococcal capsular polysaccharides (PSs) are similar in structure, and a pneumococcal antibody often binds to all of the PSs with a similar structure. Yet, these cross-reactive antibodies may bind to the structurally related pneumococcal capsular PSs with an avidity too low to be effective. If memory B cells producing such weakly cross-reactive antibodies are elicited with pneumococcal conjugate vaccines, the memory cells for low-avidity antibodies could compromise the subsequent immune responses to the cross-reactive PS (original antigenic sin). To investigate these issues, we produced 14 hybridomas secreting monoclonal antibodies (MAbs) to the capsular PS of Streptococcus pneumoniae serotype 6B by immunizing BALB/c mice with antigens containing 6B PS and studied their epitope, avidity, in vitro opsonizing capacity, in vivo protective capacity, and “antigen binding titer” by enzyme-linked immunosorbent assay (ELISA) of 6A and 6B capsular PSs. Six MAbs bound to the non-cross-reactive 6B-specific epitope, and seven MAbs bound to the cross-reactive epitope present in both 6A and 6B PSs One MAb (Hyp6BM6) revealed a novel epitope. This epitope was found on 6A PS in solution, but not on 6A PS adsorbed onto the plastic surface of the ELISA plates. The avidity of the MAb for 6A or 6B PS ranged from 7.8 × 106 M−1 to 4.1 × 1011 M−1. No MAbs were weakly cross-reactive, since none of the cross-reactive MAbs showed any tendency toward having less avidity to 6A PS (the cross-reactive PS) than to 6B PS. Avidity influenced the results of several antibody assays. When all of the hybridomas were examined, avidity strongly correlated with the titer of a unit amount of MAb to bind antigen-coated ELISA plates (r = 0.91) or to opsonize pneumococci in vitro (r = −0.85). Because both assay results are avidity dependent, the ELISA and the opsonization assay results were strongly correlated (r = 0.91), regardless of avidity. Avidity also correlated with the potency of a MAb to passively protect mice against pneumococcal infections. When only the immunoglobulin G hybridomas were examined, little increase in opsonizing capacity and in vivo protective potency was observed above 109 M−1. Taken together, an ELISA measuring antigen binding titer may be an adequate measure of the protective immunity induced with pneumococcal vaccines, and the absence of a partially cross-reactive MAb suggests that antigenic sin may not be significant in responses to vaccines against the S. pneumoniae 6B serotype.
Comparison of Staining Techniques for Scanning Electron Microscopic Detection of Ultrastructural Protuberances on Cellulolytic Bacteria

Cell surface protuberances found on cellulolytic bacteria, but not on noncellulolytic bacteria, can be detected by scanning electron microscopy. Cationized ferritin typically has been used as a stain to increase the microscopic resolution of these protuberances; however, as a cation it binds only to negatively charged molecules. Thus, binding of cationized ferritin to cell surface molecules can be affected by the cell's physiological state. We incubated the noncellulolytic bacterium, Clostridium beijerinckii, in different media at various temperatures to obtain cells with different growth rates and physiological states. Staining of these cells with cationized ferritin showed that slower growing cells exhibited more protuberant structures than faster growing cells. This provided a clear correlation of ultrastructural protuberances with physiological changes associated with growth rate. On the other hand, cells stained with osmium tetroxide exhibited no protuberant structures regardless of growth rate. Because various cations are known to induce aggregation of surface proteins on some cellulolytic Clostridia, we incubated the cellulolytic bacterium, Clostridium cellulovorans, in media containing glucose, cellobiose, or cellulose. Ultrastructural protuberances were evident on all cells stained with cationized ferritin, but extensive protuberances were detected only on cells grown in cellulose and stained with osmium tetroxide. For cells stained with cationized ferritin, the presence of ultrastructural protuberances was correlated with growth rate rather than induction of cellulolytic systems. By contrast, cells stained with osmium tetroxide showed a clear correlation between protuberant structures and cellulolytic activity.
Functional characterization of Ape1 variants identified in the human population.

Apurinic/apyrimidinic (AP) sites are common mutagenic and cytotoxic DNA lesions. Ape1 is the major human repair enzyme for abasic sites and incises the phosphodiester backbone 5′ to the lesion to initiate a cascade of events aimed at removing the AP moiety and maintaining genetic integrity. Through resequencing of genomic DNA from 128 unrelated individuals, and searching published reports and sequence databases, seven amino acid substitution variants were identified in the repair domain of human Ape1. Functional characterization revealed that three of the variants, L104R, E126D and R237A, exhibited ∼40–60% reductions in specific incision activity. A fourth variant, D283G, is similar to the previously characterized mutant D283A found to exhibit ∼10% repair capacity. The most common substitution (D148E; observed at an allele frequency of 0.38) had no impact on endonuclease and DNA binding activities, nor did a G306A substitution. A G241R variant showed slightly enhanced endonuclease activity relative to wild-type. In total, four of seven substitutions in the repair domain of Ape1 imparted reduced function. These reduced function variants may represent low penetrance human polymorphisms that associate with increased disease susceptibility.
Acute tubular necrosis associated with propylene glycol from concomitant administration of intravenous lorazepam and trimethoprim-sulfamethoxazole

A 46-year-old morbidly obese man was admitted to the medical intensive care unit with respiratory failure. He required pressure-control ventilation and high levels of sedation with continuous-infusion lorazepam. He developed Stenotrophomonas maltophilia pneumonia; treatment included scheduled intravenous trimethoprim-sulfamethoxazole. Each of these drugs contain several hundred milligrams/milliliter of propylene glycol. On day 17 of his hospital course, 3 days after starting the trimethoprim-sulfamethoxazole, the patient developed acute renal failure consistent with acute tubular necrosis. Propylene glycol toxicity was suspected; therefore, all drugs containing propylene glycol were discontinued, and laboratory data were collected. A marked osmol gap, metabolic acidosis, and renal toxicity were attributed to both continuous and large intermittent doses of intravenous propylene glycol. Particular attention should be paid to the total amount of propylene glycol provided to patients from administered drugs. Patients in the intensive care setting who require high doses of intravenous lorazepam for sedation, as well as antimicrobial therapy with trimethoprim-sulfamethoxazole for treatment of either Stenotrophomonas maltophilia or Pneumocystis carinii pneumonia, may be at increased risk for propylene glycol toxicity and should be monitored closely.
The Future of Public Administration: Challenges and Opportunities—A Critical Perspective

This article addresses the future of public administration as a self-conscious enterprise as well as a field of practice. It discusses four major challenges facing public administration: predatory globalization, institutional failure, poverty of the field, and success of the field, with technology as a fifth challenge, which is not discussed due to space limitation. The article also argues that, ironically, it is these same challenges that can also serve as forces shaping the future of public administration as a theory and practice. A conclusion outlines models suggested by other scholars, and offers new perspectives in favor of the argument advanced here.