cssi/SciSciGPT-SciSciNet huggingface dataset:
Pathways That Synthesize Phosphatidylethanolamine Impact Candida albicans Hyphal Length and Cell Wall Composition through Transcriptional and Posttranscriptional Mechanisms.

ABSTRACT Candida albicans is a leading cause of systemic bloodstream infections, and synthesis of the phospholipid phosphatidylethanolamine (PE) is required for virulence. The psd1Δ/Δ psd2Δ/Δ mutant, which cannot synthesize PE by the cytidine diphosphate diacylglycerol (CDP-DAG) pathway, is avirulent in the mouse model of systemic candidiasis. Similarly, an ept1Δ/Δ mutant, which cannot produce PE by the Kennedy pathway, exhibits decreased kidney fungal burden in systemically infected mice. Conversely, overexpression of EPT1 results in a hypervirulent phenotype in this model. Thus, mutations that increase PE synthesis increase virulence, and mutations that decrease PE synthesis decrease virulence. However, the mechanism by which virulence is regulated by PE synthesis is only partially understood. RNA sequencing was performed on strains with deficient or excessive PE biosynthesis to elucidate the mechanism. Decreased PE synthesis from loss of EPT1 or PSD1 and PSD2 leads to downregulation of genes that impact mitochondrial function. Losses of PSD1 and PSD2, but not EPT1, cause significant increases in transcription of glycosylation genes, which may reflect the substantial cell wall defects in the psd1Δ/Δ psd2Δ/Δ mutant. These accumulated defects could contribute to the decreased virulence observed for mutants with deficient PE synthesis. In contrast to mutants with decreased PE synthesis, there were no transcriptional differences between the EPT1 overexpression strain and the wild type, indicating that the hypervirulent phenotype is a consequence of posttranscriptional changes. It was found that overexpression of EPT1 causes increased chitin content and increased hyphal length. These phenotypes may help to explain the previously observed hypervirulence in the EPT1 overexpressor.
Nonmalignant complications of therapy for Hodgkin's disease.

The long-term complications of Hodgkin’s disease and its treatment are reviewed. Particular attention is placed on cardiac and pulmonary, infectious and immunologic, and endocrine and reproductive sequelae of successful therapy. The pathophysiology and clinical features of these disorders are discussed.
Recurrence and Complications in Pediatric and Adolescent Papillary Thyroid Cancer in a High-Volume Practice

Abstract Background Treatment approaches for pediatric papillary thyroid cancer (PTC) are historically extrapolated from adult experience. However, pediatric PTC demonstrates a greater propensity for lymph node involvement, early metastases, and recurrence, highlighting the need for pediatric-specific treatment paradigms. Materials and methods A retrospective review included patients with PTC aged ≤21 y, with ≥18 mo of follow-up, treated between 2002 and 2015. Fisher's exact test and Cox proportional hazard were used to estimate the effect of risk factors on disease recurrence. Results Seventy-two cases of PTC were identified with median age of 17.0 y and median follow-up of 64.1 mo. Disease recurred at a median of 24.6 mo (range 7.8-78.1) in 7 of 51 (13.7%) of patients with disease limited to the thyroid or central neck, 7 of 18 (39%) patients with lateral neck disease at presentation who underwent a compartment-based resection, and three of three patients (100%) with lateral neck disease who sought care after non–compartment-based resection. There were no deaths from disease. Univariate predictors of recurrence included tumor size >2 cm (P = 0.005), lateral neck disease (P = 0.004), lymphovascular invasion (P = 0.017), extracapsular invasion (P Conclusions Pediatric PTC is associated with excellent survival, although recurrence is common in patients with lateral node involvement. Predictors of recurrence are multifactorial and may be influenced by extent of disease, patient or tumor biology, and aggressiveness of resection. Level of evidence Prognosis study, level IV, retrospective case series.
Novel point of care strategies for biomarker detection

Stress biomarkers produced by the body are briefly reviewed and our recent research is presented. Quantitative detection using aptamer-LFA demonstrated against cortisol, dopamine, and endotoxin. Microfluidic label-free optical method presented simultaneous detection of multiple biomarkers in bodily fluids, promising real-time detection. Lastly, future biomarker detection is discussed
Intraspecific trait variability shapes leaf trait response to altered fire regimes.

Background and aims Understanding impacts of altered disturbance regimes on community structure and function is a key goal for community ecology. Functional traits link species composition to ecosystem functioning. Changes in the distribution of functional traits at community scales in response to disturbance can be driven not only by shifts in species composition, but also by shifts in intraspecific trait values. Understanding the relative importance of these two processes has important implications for predicting community responses to altered disturbance regimes. Methods We experimentally manipulated fire return intervals in replicated blocks of a fire-adapted, long leaf pine (Pinus palustris) ecosystem in North Carolina, USA and measured specific leaf area (SLA), leaf dry matter content (LDMC) and compositional responses along a lowland to upland gradient over a four-year period. Plots were burned between zero and four times. Using a trait-based approach, we simulate hypothetical scenarios which allow species presence, abundance or trait values to vary over time and compare these to observed traits to understand the relative contributions of each of these three processes to observed trait patterns at the study site. We addressed the following questions: 1) How do changes in the fire regime affect community composition, structure, and community-level trait responses? 2) Are these effects consistent across a gradient of fire intensity? and, 3) What are the relative contributions of species turnover, changes in abundance, and changes in intraspecific trait values to observed changes in community weighted mean (CWM) traits in response to altered fire regime? Key results We found strong evidence that altered fire return interval impacted understory plant communities. The number of fires a plot experienced significantly affected the magnitude of its compositional change and shifted the ecotone boundary separating shrub-dominated lowland areas from grass-dominated upland areas, with suppression sites (0 burns) experiencing an upland shift and annual burn sites a lowland shift. We found significant effects of burn regimes on the CWM of specific leaf area (SLA), and that observed shifts in both SLA and LDMC were driven primarily by intraspecific changes in trait values. Conclusions In a fire-adapted ecosystem, increased fire frequency altered community composition and structure of the ecosystem through changes in the position of the shrub line. We also found that plant traits responded directionally to increased fire frequency, with SLA decreasing in response to fire frequency across the environmental gradient. For both SLA and LDMC, nearly all of the observed changes in CWM traits were driven by intraspecific variation.
Universal Scaling in Biochemical Networks

Attempts to identify universal properties of life are limited by the single example of biochemistry on Earth. Using a global database of 28,146 annotated genomes and metagenomes, we report universal scaling laws governing the topology of biochemical networks across levels of organization from individuals, to ecosystems, to the biosphere as a whole. We show the three domains of life are topologically distinguishable, while nonetheless conforming to the same universal scaling laws. Comparing real biochemical networks to networks composed of randomly sampled biochemical reactions reveals the observed scaling is not a product of shared biochemistry alone, but is instead attributable to universal constraints on how global biochemistry is partitioned into individuals. The reemergence of the same regularities across levels of organization hints at general principles governing biochemical network architecture.
Characterizing a common CERS2 polymorphism in a mouse model of metabolic disease and in subjects from the Utah CAD Study

CONTEXT Genome-wide association studies have identified associations between a common single nucleotide polymorphism (SNP; rs267738) in CERS2, a gene that encodes a (dihydro)ceramide synthase that is involved in the biosynthesis of very-long-chain sphingolipids (eg, C20-C26) and indices of metabolic dysfunction (eg, impaired glucose homeostasis). However, the biological consequences of this mutation on enzyme activity and its causal roles in metabolic disease are unresolved. OBJECTIVE The studies described herein aimed to characterize the effects of rs267738 on CERS2 enzyme activity, sphingolipid profiles, and metabolic outcomes. DESIGN We performed in-depth lipidomic and metabolic characterization of a novel CRISPR knock-in mouse modeling the rs267738 variant. In parallel, we conducted mass spectrometry-based, targeted lipidomics on 567 serum samples collected through the Utah Coronary Artery Disease study, which included 185 patients harboring 1 (n = 163) or both (n = 22) rs267738 alleles. RESULTS In-silico analysis of the amino acid substitution within CERS2 caused by the rs267738 mutation suggested that rs267738 is deleterious for enzyme function. Homozygous knock-in mice had reduced liver CERS2 activity and enhanced diet-induced glucose intolerance and hepatic steatosis. However, human serum sphingolipids and a ceramide-based cardiac event risk test 1 score of cardiovascular disease were not significantly affected by rs267738 allele count. CONCLUSIONS The rs267738 SNP leads to a partial loss-of-function of CERS2, which worsened metabolic parameters in knock-in mice. However, rs267738 was insufficient to effect changes in serum sphingolipid profiles in subjects from the Utah Coronary Artery Disease Study.
Boundaries Crossed and Boundaries Made: The Productive Tension Between Learning and Influence in Transformative Networks

We present an in-depth case study of a learning network that aims to transform infrastructure and practice across the research enterprise to advance societal impacts. The theory of social morphogenesis guides our processual qualitative analysis of the network. We describe how different types of boundary work, both building and navigating across boundaries, operate in tension while contributing to transformative capacity. We conclude that learning networks can play a robust role in fostering transformation by drawing together and holding together forces which expand knowledge and authority over time iteratively and recursively. In addition to this theoretical contribution, we provide practical guidance for how network leaders can dynamically manage boundaries, shifting emphasis between strength and fluidity to support transformative change across sites and scales.
Abstract 1404: Loss of adenomatous polyposis coli induces DOX resistance through upregulation of ABC transporters

Chemoresistance is a leading cause of breast cancer related deaths. Therefore, understanding the molecular basis for chemoresistance is essential for novel therapeutic advancement improving patient outcome. The Adenomatous Polyposis Coli (APC) tumor suppressor is lost in up to 70% of sporadic breast cancer; however, little is known about how APC loss contributes to chemoresistance. Using mammary tumor cells isolated from the ApcMin/+ mouse crossed to the Polyoma middle T antigen (PyMT) transgenic model, we were the first to show that APC loss decreased doxorubicin (DOX) induced apoptosis. Therefore, we examined the mechanisms contributing to DOX resistance with APC loss to identify combination therapy options. We previously made the novel observation that APC loss in MMTV-PyMT;ApcMin/+ cells activated signal transducer and activator of transcription 3 (STAT3) thereby increasing the expression of the drug efflux pump, multidrug resistance protein 1 (MDR1). ATP-binding cassette (ABC) transporters, such as MDR1, are one of the most well-known contributors to drug resistance. These ABC transporters are capable of exporting drugs from the cell preventing apoptosis. Decreased intracellular DOX accumulation was observed in APC-deficient cells suggesting enhanced drug efflux. To investigate this decreased intracellular DOX accumulation, we measured the expression and activity of the drug export pumps, MDR1 and multidrug resistance protein 1 (MRP1). APC-deficient cells also have increased expression of MRP1. We used a calcein incorporation assay and demonstrated that APC loss increased MDR1 activity, which was restored by an MDR1 inhibitor. In addition, MDR1 inhibition sensitized the MMTV-PyMT;ApcMin/+ cells to DOX-mediated apoptosis. MRP1 inhibition through genetic manipulation will be used to assess MRP1 activity using the calcein AM assay and its contribution to DOX resistance. MDR1 and MRP1 inhibition will also be used to restore intracellular DOX accumulation. Future studies including evaluating human tumor protein lysates will for APC, MDR1, and MRP1 expression. Correlation studies will be used to determine whether loss of APC correlates with either high expression of MDR1 or MRP1. Taken together, APC loss mediates DOX resistance via exporting DOX demonstrating the potential use of combination therapy to overcome chemoresistance. Citation Format: Casey D. Stefanski, Jenifer R. Prosperi, Lauren Milac. Loss of adenomatous polyposis coli induces DOX resistance through upregulation of ABC transporters [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1404.
Global phylogenomic analyses of Mycobacterium abscessus provide context for non cystic fibrosis infections and the evolution of antibiotic resistance.

Mycobacterium abscessus (MAB) is an emerging pathogen that leads to chronic lung infections. To date, the global population structure of non-cystic fibrosis (CF) MAB and evolutionary patterns of drug resistance emergence have not been investigated. Here we construct a global dataset of 1,279 MAB whole genomes from CF or non-CF patients. We utilize whole genome analysis to assess relatedness, phylogeography, and drug resistance evolution. MAB isolates from CF and non-CF hosts are interspersed throughout the phylogeny, such that the majority of dominant circulating clones include isolates from both populations, indicating that global spread of MAB clones is not sequestered to CF contexts. We identify a large clade of M. abscessus harboring the erm(41) T28C mutation, predicted to confer macrolide susceptibility in this otherwise macrolide-resistant species. Identification of multiple evolutionary events within this clade, consistent with regain of wild type, intrinsic macrolide resistance, underscores the critical importance of macrolides in MAB. Mycobacterium abscessus is an emerging infection that usually affects patients with structural lung diseases such as cystic fibrosis (CF). Here, the authors use phylogenetic analyses to demonstrate close relationships between isolates from CF and non-CF patients and identify antibiotic resistance markers.
Ventral Hernia Repair

This section covers the different types of ventral hernias including the umbilical hernia, epigastric hernia, Spigelian hernia, and incisional hernia. The technique of both open and laparoscopic ventral hernia repair is discussed, as are the most common postoperative complications. A classic case of an incisional hernia as a result of a wound infection is described, and questions are provided for review.
Ca2+ Ion Shifts in Vivo in Reversible and Irreversible Ischemic Injury

The changes in ion content and H2O detectable in vivo in the intact canine heart in reversible and irreversible ischemic injury are described, with emphasis on the role Ca2+ movements may play in causing ischemic injury. Changes in extracellular ion concentrations and pH revealed by ion-specific electrodes in ischemia are reviewed, as are the contributions of nuclear magnetic resonance measurements of ionized Ca2+ to our understanding of Ca2+ ion homeostasis in ischemia.
Skeletal Muscle Afferents

Publisher Summary The constellation of cardiovascular and respiratory responses evoked by the stimulation of skeletal muscle afferents has been termed “the exercise pressor reflex.” The purpose of the exercise pressor reflex is to deliver oxygenated blood to metabolically active tissues (that is, the exercising muscles) and to remove carbon dioxide and hydrogen ions from these tissues. In addition, the exercise pressor reflex contributes significantly to the increase in cardiac output evoked by dynamic exercise. The reflex increases sympathetic discharge to the vascular beds of dynamically exercising muscles, an effect that partly counters the increase in vascular conductance, which, in turn, is caused by the increase in muscle metabolism. The exercise pressor reflex also plays an important role during static exercise. The afferent limb of the exercise pressor reflex is composed of group III and IV afferents, which together are called “thin fiber afferents.” Groups Ia, Ib, and II play no role in evoking this reflex.
UHV transmission electron microscopy of Ir(001): I. Microstructure of the (1 × 1) and the reconstructed (5 × 1) surfaces

Experimental results on the unreconstructed Ir(001)-(1 × 1) and the reconstructed (5 × 1) surfaces using plan view ultra-high vacuum transmission electron microscopy (UHV-TEM) are presented. The contamination-stabilized Ir(001)-(1 × 1) surface is moderately well ordered with steps preferentially aligned along 〈110〉 and 〈100〉 directions, but is fairly rough on the atomic scale as evidenced by both dark field and high resolution imaging. The step evolution and the microstructure of the surface with repeated annealing are described. The Ir(001)-(5 × 1) reconstruction is determined by electron diffraction to be a simple quasi-hexagonal surface layer with very little distortion in a (5 × 1) registry with respect to the bulk. This surface is a much flatter one than the (1 × 1). The basic morphology of the reconstructed surface layer is shown by dark field microscopy, and the transition from (1 × 1) to (5 × 1) is a nucleation and growth process. Evidence for subsurface IrO2 precipitate particles is also presented.
The challenge of inter-organization system design comparative case study of videoconferencing systems

A comparative case study was conducted to assess the consequences of implementing a videoconferencing system in three organizations developing two inter-organization systems (IOS): a county-hospital and a county-nursing home. Respondents reported radically different experiences with the videoconference technology.
An investigation into non-smooth locomotion

We analyze a class of mechanisms that locomote by switching between constraints. Because of the hybrid nature of such systems, most of the existing analysis tools, developed primarily for smooth systems, can not be directly applied. Our aim is to exploit the special structure provided by Lagrangian mechanics to study the controllability of this class of mechanisms. We base the analysis on a series representation of the evolution of the system. Our main result is a description of trajectories involving switches between constraints at nonzero velocity (impacts) in the presence of large inertial forces (drift). The analysis provides a basis for local motion planning. The results are applied to an example of a two-link planar mechanism that can locomote by clamping one of the links.
Bonding, Interfacial Effects And Adhesion In DLC.

Metastable, amorphous carbon films, also referred to as diamond-like carbon (DLC), are prepared in a large variety of deposition conditions. Depending upon the conditions, DLC films may contain large amounts of hydrogen, and are referred to as hydrogenated amorphous carbon. The properties of DLC are strongly dependent on the preparation conditions and upon the amount of hydrogen incorporated in the film. Due to its extreme hardness, DLC can be used as a wear protective coating, while its chemical inertness to acids and alkali's make it suitable for protection against chemical attack. The optical transparency of the DLC over a large region of the spectrum makes it useful as a protective coating of optical components. However, hydrogenated DLC is usually also characterized by very high compressive stresses. Its application as a protective coating therefore requires strong adhesive bonds to the coated surface. The paper reviews structural and optical properties of DLC films and means of improving their adhesion to metallic surfaces.
Tumor necrosis factor-α from resident lung cells is a key initiating factor in pulmonary ischemia-reperfusion injury

Abstract Objective A central role of macrophages in initiating lung ischemia-reperfusion injury is emerging. Tumor necrosis factor-α is a proinflammatory cytokine secreted mainly by macrophages under various conditions. We hypothesized that tumor necrosis factor-α from resident lung cells is a key initiating factor in pulmonary ischemia-reperfusion injury. Methods We used an isolated, buffer-perfused lung system to explore the role of tumor necrosis factor-α production by resident lung cells in pulmonary ischemia-reperfusion injury. Lungs from wild-type mice and tumor necrosis factor-α–deficient mice were subjected to 60 minutes of ischemia followed by 60 minutes of reperfusion. Histologic injury scores and measurements of lung compliance, airway resistance, mean pulmonary artery pressure, vascular reactivity, and wet lung weight index were obtained and compared using repeated-measures analysis of variance. Results Lungs from tumor necrosis factor-α–deficient mice showed significantly less injury in all physiologic parameters throughout the entire 60 minutes of reperfusion compared with lungs from wild-type mice ( P Conclusions By using the advantages of a nonblood-perfused system, we have focused our investigation on resident lung cells. Our results demonstrate that resident cell-produced tumor necrosis factor-α is a key initiating factor in acute lung ischemia-reperfusion injury.
Structures of C60 intercalation compounds

Abstract In the past two years, many intercalation compounds of C 60 , have been prepared and characterized by X-ray powder diffraction techniques. The M-C 60 systems with M = Li, Na, K, Rb, Cs and Ca have been studied, and the structures of several compounds have been determined in considerable detail, including the face-centered cubic superconductors K 3 C 60 and Rb 3 C 60 , body-centered tetragonal K 4 C 60 , body-centered cubic M 6 C 60 with M = K, Rb and Cs, simple hexagonal C 60 I 4 , and the monoclinic molecular ferromagnet tetrakis-dimethylamino-ethylene (TDAE) C 2 N 4 (CH 3 ) 8 C 60 . The Rietveld profile technique for structure refinement coupled with high resolution synchrotron X-ray powder data has played an important role in providing accurate structural data for many of these compounds. In this article, a detailed review of the literature dealing with structural studies on the intercalated compounds of C 60 will be given.
Bioreduction of selenate using a hydrogen-based membrane biofilm reactor

A H2-based, denitrifying and sulfate-reducing membrane-biofilm reactor (MBfR) was shown to be effective for removing selenate (Se(VI)) from water or wastewater by reducing it to insoluble Se0. When Se(VI) was first added to the MBfR, Se(VI) reductionfirst to selenite (Se(IV)) and then mostly to Se0took place immediately and then increased over three weeks, suggesting enrichment for dissimilatory selenium-reducing bacteria. Increasing the H2 pressure improved the Se(VI) reduction rate and total-Se removal, and lowering the influent Se(VI) concentration from 1000 to 260 μg Se/L increased the average Se removal to 94%, which corresponded to an effluent Se concentration of less than 12 μg Se/L, a value well below the standard of 50 μg Se/L. The fact that the effluent suspended solids contained reduced Se suggests that Se0 was retained in the biofilm, which detached to form the effluent suspended solids. A series of short-term experiments elaborated on how decreased influent selenate loading and increased H2 p...
Long-term potentiation in the hippocampus involves activation of N-methyl-D-aspartate receptors

A series of omega-phosphono-alpha-carboxylic acids were tested as antagonists of excitatory amino acid depolarizations and long-term potentiation (LTP) in region CA1 of rat hippocampal slices. The 5- and 7-phosphono compounds (+/- AP5 and +/- AP7) blocked N-methyl-D-aspartate (NMDA) depolarizations and prevented the induction of LTP of the synaptic field potential and population spike components of the Schaffer collateral response. +/- AP5 and +/- AP7 did not reduce kainate or quisqualate depolarizations and did not affect unpotentiated synaptic response amplitude. +/- AP4, +/- AP6 and +/- AP8 did not block amino acid excitant responses or LTP. These results demonstrate that NMDA receptors present in hippocampal region CA1 are not necessary for normal synaptic transmission, but are involved in the initiation of long-term synaptic plasticity.
Scheduling groups of jobs on a single machine

Economies of scale are fundamental to manufacturing operations. With respect to scheduling, this phenomenon manifests itself in efficiencies gained from grouping similar jobs together. This paper reviews the rapidly growing literature on single-machine scheduling models that incorporate benefits from job grouping. We focus on three basic models known as family scheduling with item availability, family scheduling with batch availability, and batch processing. We present known results and introduce new results, and we pay special attention to key theoretical properties and the use of these properties in optimization procedures.
1.8 Watt RF Power and 60% Power Conversion Efficiency Based on Photodiode Flip-chip-bonded on Diamond

A 1.8 W RF output power at 10 GHz and 60 % power conversion efficiency (PCE) at 6 GHz have been achieved using a modified uni-traveling-carrier photodiode flip-chip bonded on diamond.
“Audacia Dangyereyes”: Appropriate Speech and the “Immodest” Woman Speaker of the Comstock Era

In the 1870s and ‘80s, more women discussed sex to promote free love and sex education in speeches, pamphlets, books, and periodicals. Some of these women inspired the 1873 “Comstock law,” which banned materials deemed obscene. This essay uses the fictional figure of Audacia Dangyereyes to illustrate the constraints on women discussing sex in public forums. It identifies the rhetorical moves necessary to accommodate constraining audiences through close readings of the works of Victoria Woodhull, Tennessee Claflin, and Angela Heywood, all women deemed immodest by public standards and obscene by Anthony Comstock. To allay such charges, these women worked to redefine appropriate speech for women.
Probing the Structure and Function of TMC1 in Sensory Hair Cells using Mutagenesis and Cysteine Modification

Transmembrane channel-like genes 1 and 2 (Tmc1 and Tmc2) have recently been implicated as components of the sensory transduction channel in mammalian hair cells. Mice deficient in both Tmc1 and Tmc2 have complete loss of hearing and balance function and lack sensory transduction, despite intact hair bundles and tip-links (Kawashima et al., 2011). Mice that express only TMC1 or TMC2 have distinct single-channel conductances and calcium selectivity. A methionine-to-lysine substitution at position 412 in TMC1 reduces the single-channel current amplitude and calcium permeability of transduction (Pan et al., 2013). These results suggest that TMCs participate as essential components of the sensory transduction channel in auditory and vestibular hair cells, but their exact role is not yet clear. They may form a vestibule at the mouth of the pore, the pore of the ion channel itself or both (Holt et al., 2014). Alternatively, TMCs may function as non-essential accessory subunits (Beurg et al., 2014). Progress toward understanding the structure and function of TMC proteins has been limited by the lack of homology to known genes or domains (Kurima et al., 2003); the low quantity of native protein (50-100 functional channels/cell); and poor membrane localization in heterologous cells. To circumvent these limitations, we combined electrophysiological recording with mutagenesis and cysteine modification in native hair cells. To probe TMC1 structure and function, mutant Tmc1 sequences were introduced, via viral transfection, into organotypic cultures harvested from Tmc1/Tmc2 doubly-deficient mice. We find that the mutant constructs restore sensitivity to hair bundle deflections in virally-transfected hair cells and that acute application of cysteine modification reagents alters the biophysical properties of sensory transduction within seconds. The data further support a direct role for TMC1 in sensory transduction in mammalian hair cells.
Images of the Classroom and Visions of the Learner

Almost within sight of my office are four school buildings. In one, dating from the turn of the century, the spaces called classrooms are rectangular in shape, the pupils' chairs are firmly bolted to the floor in straight rows, and the teacher's desk is front and center. In the second building, dating from the 1930s, the classrooms are square, the pupils' chairs are movable into various patterns around the room, and the teacher's desk is out of the way in a corner. In the third building, dating from the 1950s, the classrooms are also square but the pupils' movable desks are now trapezoidal in shape so that when they are placed next to each other they make a circle, and the teacher's desk has vanished! In the fourth building, there is a classroom, constructed a year or so ago, that is four times the size of the ordinary classroom. It has no teacher's or pupils' desks at all but is filled instead with odds and ends, from fish bowls and birds' nests to drawing boards and Cuisinaire rods. If one were not told it was a classroom, this space might be mistaken for an overgrown playroom or a warehouse full of children's paraphernalia. I shall refer to the spaces in the first building as the "rectangular" classroom, in the second as the "square" classI am grateful to Professor Benjamin D. Wright, who contributed valuable comments on an earlier draft of the paper.
Dissolved Organic Matter Apparent Molecular Weight Distribution and Number-Average Apparent Molecular Weight by Batch Ultrafiltration

Knowledge of dissolved organic matter (DOM) size distribution is of tremendous practical significance in both natural and engineered aquatic and terrestrial systems. This study was conducted to dem...
Good Stewards in Trying Times: Benchmarking Peer Collections of Sociology Reference Sources Using LibGuides

This article describes a method for using LibGuides as a tool for collection development by benchmarking peer (Carnegie or other classification) institutions’ reference resource recommendations. The results of this benchmarking can be used to build strong, compact collections. Although the focuses of this study are on building and maintaining of a sociology reference collection, the method transfers directly to other subject areas.
Proton Conductivity of Acid-Functionalized Zeolite Beta, MCM-41, and MCM-48: Effect of Acid Strength

Direct methanol fuel cells (DMFCs) and hydrogen proton exchange membrane fuel cells (PEMFCs) are two types of fuel cells where commercial products have been developed, but have yet to find widespread deployment. Although these devices are compact, easily refuelable, and operate at comparatively low temperatures, problems such as catalyst poisoning, methanol crossover, and water management exist and are current topics of research. One important component of both the DMFC and PEMFC is a protonically conducting but electronically insulating membrane placed between the anode and cathode. To minimize internal ohmic losses, the membrane must possess a high proton conductivity, and is commonly formed from Nafion or other perfluorosulfonic acid polymers. When fully hydrated, these polymers exhibit proton conductivites on the order of 1 × 10^(-1) to 1 × 10^(−2) S/cm. For hydrogen PEMFC without active humidification, proton conductivity decreases rapidly with increasing temperaure. For DMFC, membrane swelling allows methanol diffusion directly from anode to cathode decreasing cell efficiency.
Defining intermediate stages in cell determination: Acquisition of a lens-forming bias in head ectoderm during lens determination

Cell determination in vertebrates requires integration of many events, although the mechanisms controlling the different stages in this process are poorly understood. While studies of lens determination have helped define some of these stages, we know very little about the intermediate steps involved in the commitment of ectoderm to lens formation. Lens determination begins during gastrulation when ectoderm is briefly competent to respond to lens-inducing signals and progresses to a point, at the neural tube stage, when the presumptive lens ectoderm is specified. Between these two stages important regulatory genes are activated in the presumptive lens ectoderm, including the transcription factor Pax-6, and transplantation experiments presented here suggest that the presumptive lens ectoderm is becoming “biased” toward lens formation. We show that competent ectoderm from Xenopus laevisembryos forms well-differentiated lenses in most cases when transplanted to the presumptive lens area of neural plate stage hosts, where the lens-inductive environment is strong. When placed into later, neural tube stage hosts, optimally competent ectoderm does form small lenses in about half the cases, but the overall response is much weaker. Even in this weakly inducing environment, however, lens ectoderm that is part way through the inductive process (at the neural plate stage) is shown to have a lens-forming bias, since it forms well differentiated lenses in nearly all cases. While we find that ectoderm surrounding the lens-forming area at neural plate stages does not have a lens-forming bias, non-lens head ectoderm at the neural tube stage does, suggesting that a large region of head ectoderm is biased during neurulation. Using Rana palustrisembryos, a species used in the earliest lens induction studies, we were also able to show that the optic vesicle can induce lenses in non-lens head ectoderm at neural tube stages. These results lead us to refine the definition of lens cell determination and provide a context that should allow clarification of determination mechanisms. Dev. Genet. 20:246–257, 1997. © 1997 Wiley-Liss, Inc.
Charge-Coupled-Device Characterization, Modeling, And Application

It has been 17 years since Boyle and Smith of Bell Laboratories announced in March of 1970 the concept of charge coupling. The original form of their invention was a simple 8 bit register that was used to demonstrate a semiconductor equivalent to the magnetic bubble memory. Since then, the charge-coupled device (CCD) has been the subject of active research at laboratories throughout the world, where efforts have been directed toward signal processing and imaging applications (the CCD memory never got off the ground). It is in the field of imaging applications that CCDs have clearly made their greatest contribution, revolutionizing both scientific and commercial optical imaging instrumentation.
FALSE POSITIVE HYDROGEN TEST WITH PLATINUM ELECTRODE IN PULMONARY WEDGE POSITION.

Abstract Twenty-eight of 31 patients without a left-to-right shunt showed a false positive hydrogen test when the electrode was in a pulmonary artery wedge position. As a probable explanation, the wedged catheter might stop forward flow locally and permit retrograde diffusion of hydrogen from the capillaries to the electrode, aided by the pulse wave from the left atrium.
An endurance training programme for frequent manual carrying tasks.

Abstract This study was conducted with the aim of testing whether the endurance time of new employees engaged in frequent industrial carrying tasks can be significantly increased through a short training programme (2-5 weeks). Endurance time was here defined as the maximum length of time during which an individual can continuously carry a 20 kg load over a 4 m distance 8 times/min. The results showed that (1) endurance time increased by almost 100% over an 8-session training programme; (2) for a fixed workload, endurance time increased without changing job demand perception; and (3) overall body fatigue may be the limiting factor in frequent carrying tasks
Morphine withdrawal aggression: modification with D1 and D2 receptor agonists

Morphine withdrawal increases aggressive behaviors, induces explosive motor behaviors, and disrupts homeostatic functions in mice and rats. While many of these effects appear to result from altered dopaminergic activity during morphine withdrawal, the relative contributions of the D1 and D2 receptor subtypes remain unclear. In the present experiments, the D1 agonist SKF 38393 and the D2 agonist quinpirole were administered to male “resident” Swiss-Webster mice 5 h after the removal of a subcutaneously-implanted morphine or placebo pellet. These mice were then observed alone to determine changes in various motor activities and in confrontation with a group-housed male “intruder” to assess changes in aggressive behaviors. SKF 38393 decreased the display of aggressive behaviors by placebo and morphine-withdrawn mice without consistently altering walking or rearing. Quinpirole greatly decreased the display of aggressive behaviors by placebo mice and decreased aggressive behaviors in morphine-withdrawn mice to a lesser degree. The inhibitory effects of quinpirole were not specific to aggressive behaviors; low quinpirole doses also decreased the display of walking and rearing. In mice which received a low dose of SKF 38393 preceding quinpirole injection, pretreatment with the D1 agonist did not alter the effects of the D2 agonist quinpirole on motor activities but maintained high levels of aggression in morphine-withdrawn mice. The differential modification of aggressive and motor behaviors by selective dopaminergic agonists during morphine withdrawal further supports the suggestion that aggressive and motor behaviors are controlled independently; furthermore, D1 receptor stimulation appears to have particular relevance for the display of aggressive behaviors during morphine withdrawal.
Generating a Production compiler from an Attribute Grammar

Must automatically generated compilers use inordinate amounts of memory? Here is evidence that AG-based systems hold the potential for efficient commercial operation.
Promoting reflection and interpretation in education: curating rich bookmarks as information composition

Reflection, interpretation, and curation play key roles in learning, creativity, and problem solving. Reflection means looking back and forward among building blocks constituting a space of ideas, contextualizing with processes including tasks, activities, and one's internal thinking and meditating, and deriving new understandings, known as interpretations. Curation, in the digital age, means searching, gathering, collecting, organizing, designing, reflecting on, and interpreting information.We introduce rich bookmarks, representations of key ideas from documents as navigable links that integrate visual clippings and rich semantic metadata. We support curating rich bookmarks as information composition. In this holistic visual form, curators express relationships among curated elements through implicit visual features, such as spatial position, color, and translucence.We investigated the situated context of a university course, engaging educators in iterative co-design. Rich bookmarks emerged in the process, motivating changes in pedagogy and software. Changes provoked students to collect more novel and varied ideas. They reported that curating rich bookmarks as information composition helped them reflect, transforming prior ideas into new ones. The visual component of rich bookmarks was found to support multiple interpretations; the semantic to support associational exploration of related ideas.
Three-dimensional liquid surfaces through nanoparticle self-assembly

Nanoparticles blended into thin polymer films are driven to assemble at interfaces by both entropic and enthalpic forces. When nanoparticles assemble at a substrate–polymer film interface, these forces are so large that they enable the film to follow surface protrusions and form a three-dimensional surface, instead of dewetting from the substrate. In other words, disassembling the nanoparticle layer requires more energy than that gained by the film dewetting from the rough surface. Here we studied blends of linear polystyrene and CdSe nanoparticles spin coated onto silicon substrates containing sparsely distributed SiO2 particles (ca. 120 nm diameter). The films were then thermally annealed for periods of up to 24 h, well above the glass transition temperature of the polymer. The profiles of different film thicknesses (40–180 nm) were characterized using atomic force microscopy (AFM) before and after being annealed and were found to become much smoother, yet remain three-dimensional after annealing with a profile that gradually decayed away from the SiO2 particles. Calculations based on a continuum theory using a balance of assembly, dispersion and surface tension forces were performed and found to be in agreement with the AFM profile data demonstrating the strength of the assembly forces.
Localization of classical waves. I. Acoustic waves

We consider classical acoustic waves in a medium described by a position dependent mass density ϱ(x). We assume that ϱ(x) is a reandom perturbation of a periodic function ϱ0(x) and that the periodic acoustic operator\(A_0 = - \nabla \cdot \tfrac{1}{{\varrho _0 (x)}}\nabla \) has a gap in the spectrum. We prove the existence of localized waves, i.e., finite energy solutions of the acoustic equations with the property that almost all of the wave's energy remains in a fixed bounded region of space at all times, with probability one. Localization of acoustic waves is a consequence of Anderson localization for the self-adjoint operators\(A = - \nabla \cdot \tfrac{1}{{\varrho _0 (x)}}\nabla \) onL2(ℝd). We prove that, in the random medium described by ϱ(x), the random operatorA exhibits Anderson localization inside the gap in the spectrum ofA0. This is shown even in situations when the gap is totally filled by the spectrum of the random opertor; we can prescribe random environments that ensure localization in almost the whole gap.
Verifying Performance for Autonomous Robot Missions with Uncertainty

Abstract Establishing performance guarantees for robot missions is especially important for C-WMD applications. Software verification techniques, such as model checking (Clark 1999, Jhala & Majumdar 2009), can be applied to robotic applications but characteristics of this application area, including addition of a robot environment model and handling continuous spatial location well, exacerbate state explosion, a key weakness of these methods. We have proposed an approach to verifying robot missions that shifts the focus from state-based analysis onto the solution of a set of flow equations (Lyons et al. 2012). The key novelty introduced in this paper is a probabilistic spatial representation for flow equations. We show how this representation models the spatial situation for robot motion with environments or controllers that include discrete choice (constraints). A model such as we propose here is useful only if it can accurately predict robot motion. We conclude by presenting three validation results that show this approach has strong predictive power; that is, that the verifications it produces can be trusted.
Treating spontaneous tumors in dogs and cats by ultrasound-induced hyperthermia.

Abstract Pet cats ans dog with spontaneous malignant tumors were used for a preclinical study of hyperthemia induced by ultrasound. A variety of surface tumors were heated to 43.0–44.5°C by a cm ultrasound transducer. Skin pverlying the tumors was cooled by a circulating water jacket. Frequencies of 0.75–5 MHz were utilized depending on the depth of heating desired. The intensity of the energy output of the transducer was relatively uniform across a 2 cm diameter. Tumors were often cooler in the periphery than at the center, probably because of the effects of blood flow. In 22 courses of treatment, 3 complete regressions and 9 partial regressions were seen for an overall response rate of 55%. Squamos cell carcinoma appeared to be most responsive; 7 8 animals responded. There was no apparent correlation between temperature or duration of treatment and response rate. No systemic effects were noted. The only untoward effects were surface burns, usually occuring at the site of thermocouple insertion. These healed rapidly and completely. The studies indicate that ultrasound is an effective and safe method of heating surface tumors and causes regression in some spontaneous tumors. Pet animals with spontaneous tumors may prove to be a good model for human cancer.
Growing evidence for balance and vestibular problems in children

Reports of vestibular deficits and related impairments in children are increasing in number. However, vestibular dysfunction in childhood appears to be an under-reported and overlooked entity. This report provides an overview of current literature regarding the incidence of vestibular deficits in children, the related impairments of gaze stability and balance and intervention for vestibular related impairments in children.
Are there gender differences in work ethic? An examination of the measurement equivalence of the multidimensional work ethic profile

Previous research has indicated that males and females differ on their reported levels of work ethic. However, previous studies have relied upon work ethic inventories with limited generalizability, and no study has evaluated the invariance of measures. This study examined measurement invariance by exploring the differential item and test functioning of one work ethic inventory, the multidimensional work ethic profile (MWEP; Miller, Woehr, & Hudspeth, 2002) for male and female respondents. Results did not indicate that the MWEP functioned differently by gender at the test or item level. Hence, work ethic as measured by the MWEP does not carry different socially constructed meanings for men versus women. We also conclude that in contrast with previous research, women do not have a higher level of work ethic than men.