cssi/SciSciGPT-SciSciNet huggingface dataset:
Membrane-Destabilizing Properties of C2-Ceramide May Be Responsible for Its Ability To Inhibit Platelet Aggregation†

We have studied the effects of short-chain ceramides on platelet structure and function. N-Acetylsphingosine (C2-ceramide), a cell-permeable short-chain analogue, and N-acetyldihydrosphingosine (C2-dihydroceramide), which lacks the 4-5 double bond, have been investigated. C2-Ceramide (15 microM) inhibited ADP-induced aggregation by 50% at a platelet concentration of 1.25 x 10(8)/mL, while it took twice that concentration to inhibit aggregation by 50% when the platelet concentration was doubled. This indicates that the effect of C2-ceramide on ADP-induced platelet aggregation depends on the ratio of ceramide to total platelet lipid, with a ratio of 0.2 giving significant inhibition. C2-Ceramide at a ceramide: lipid ratio of 0.2 caused platelets to form fenestrations and pseudopodia which were longer and thinner than those caused by agonists such as ADP or thrombin. C2-Dihydroceramide had no effect on ADP-induced aggregation or platelet morphology at any ceramide:lipid ratio. Platelet lysis was induced by C2-ceramide at higher ceramide:lipid ratios (0.5), whereas C2-dihydroceramide did not induce lysis, suggesting that C2-ceramide is able to destabilize membranes. This was tested directly by assessing whether the ceramides induced leakage of 6-carboxyfluorescein from lipid vesicles. C2-Ceramide caused nearly total leakage of dye from the vesicles at a ceramide:lipid ratio of 10. The leakage caused by C2-dihydroceramide at a ceramide:lipid ratio of 10 was equal to that induced by C2-ceramide at a ratio of 0.2 (approximately 3%). The ability of the ceramides to destabilize membranes was also examined by measuring changes in fluorescence anisotropy of the fluorescent dye 1,6-diphenyl-1,3,5-hexatriene (DPH) incorporated into lipid vesicles. C2-Ceramide induced a larger decrease in anisotropy than a detergent (Triton X-100) which is known to lyse membranes. C2-Dihydroceramide did not alter membrane fluidity. The ability of C2-ceramide to cause platelet fenestrations, formation of irregular platelet pseudopodia, platelet lysis, lipid vesicle leakage, and increases in the fluidity of lipid vesicles all suggest that C2-ceramide inhibits platelet aggregation because it destabilizes the platelet membrane. C2-Dihydroceramide did not inhibit platelet aggregation and lacked the nonspecific effects on membranes that C2-ceramide possessed, suggesting that C2-dihydroceramide is not an appropriate control for the nonspecific effects of C2-ceramide.
Distinguishing aggregation from random mixing in aqueous t-butyl alcohol solutions

Raman spectroscopic measurements are combined with various multivariate curve resolution (Raman-MCR) strategies, to characterize the aggregation of t-butyl alcohol (TBA) in aqueous solutions. The resulting TBA solute-correlated (SC) spectra reveal perturbed water OH features arising from the hydration-shell of TBA as well as shifts in the TBA CH vibrational frequency arising from TBA–TBA interactions. Our results indicate that at low concentrations (below ∼0.5 M), there is virtually no TBA aggregation. The first aggregates formed above 0.5 M remain highly hydrated, while those formed above ∼2 M are significantly less hydrated. Comparisons with predictions pertaining to a randomly mixed (non-aggregating) solution indicate that below ∼1 M there are fewer TBA–TBA contacts than would be present in a random mixture, thus implying that the thermodynamic stability of the first hydration-shell of TBA suppresses the formation of direct contact aggregates at low TBA concentrations. Our results further suggest that microheterogeneous domains containing many water-separated TBA–TBA contacts form near a TBA concentration of ∼1 M, while at higher concentrations the TBA-rich domain size distribution may resemble that in a non-aggregating random mixture.
Histone H1: Ultracentrifugation studies of the effects of ionic strength and denaturants on the solution conformation

Abstract The conformation of histone H1 has been examined under native and denaturing conditions in the absence of DNA or chromatin. Sedimentation coefficients were determined for Histone H1 in 0.1 m KCl and in 6 m guanidine hydrochloride solutions at pH 7.4. The influence of ionic strength on the conformation of histone H1 has been determined by measurement of the sedimentation coefficient in tetramethylammonium chloride solutions of up to 2.5 m and extrapolated to infinite ionic strength. Results from these experiments suggest that the native conformation of histone H1 is very asymmetric in shape. The molecule is best described as a prolate ellipsoid with axes of 312 A (2a) and 16 A (2b) in low ionic strength media and also as a prolate ellipsoid with axes of 202 A (2a) and 20 A (2b) at high ionic strength or when associated with polyanions, e.g., DNA. Denaturation of histone H1 by guanidine hydrochloride was found to be completely reversible. In 6 m guanidine hydrochloride, the H1 molecule collapses to a sphere but the original extended conformation of the protein is readily restored on dialysis. This suggests rigid conformational requirements for the H1 molecule as incorporated into chromatin. The shape and dimensions for the H1 molecule at high ionic strength are not sufficiently conclusive to locate H1 in the chromatin structure. It is proposed, however, that viable models for chromatin architecture must be consistent with the histone H1 solution dimensions obtained here.
Functionalities for automatic metadata generation applications: a survey of metadata experts' opinions

This paper reports on the automatic metadata generation applications (AMeGA) project's metadata expert survey. Automatic metadata generation research is reviewed and the study's methods, key findings and conclusions are presented. Participants anticipate greater accuracy with automatic techniques for technical metadata (e.g., ID, language, and format metadata) compared to metadata requiring intellectual discretion (e.g., subject and description metadata). Support for implementing automatic techniques paralleled anticipated accuracy results. Metadata experts are in favour of using automatic techniques, although they are generally not in favour of eliminating human evaluation or production for the more intellectually demanding metadata. Results are incorporated into Version 1.0 of the Recommended Functionalities for automatic metadata generation applications (Appendix A).
Bubble entrainment with drops

Abstract The study reported here was undertaken because recent research on nucleate boiling has implicated vapor entrainment by drops as a mechanism for vapor bubble nucleation. The mechanism has been called secondary nucleation. The purpose of this research was to determine the behavior of entrained air bubbles when a drop of liquid strikes a liquid surface. A liquid drop striking the surface of a pool of the same liquid was found usually to entrain large numbers of small air bubbles. Some of these bubbles are frequently carried rapidly deep into the pool by a vortex ring but many can be deposited in a trail or left floating on the surface. Air bubble entrainment was observed with water and several organic liquids and some differences were noted. Drops with diameters from 200 μm to 4 mm were studied. Sometimes hundreds of bubbles were entrained some with diameters up to 100 μm. These results lend support to the secondary nucleation hypothesis and indicate further research on vapor bubble entrainment under conditions more typical of boiling would be appropriate.
Scaling tests of the improved Kogut-Susskind quark action

Improved lattice actions for Kogut-Susskind quarks have been shown to improve rotational symmetry and flavor symmetry. In this work we find improved scaling behavior of the {rho} and nucleon masses expressed in units of a length scale obtained from the static quark potential, and better behavior of the Dirac operator in instanton backgrounds. (c) 2000 The American Physical Society.
The role of the polyamine catabolic enzymes SSAT and SMO in the synergistic effects of standard chemotherapeutic agents with a polyamine analogue in human breast cancer cell lines.

Introduction Polyamine analogues have demonstrated significant activity against human breast cancer cell lines as single agents as well as in combination with other cytotoxic drugs. This study evaluates the ability of a polyamine analogue N1,N11-bis(ethyl)norspermine (BENSpm) to synergize with six standard chemotherapeutic agents, 5-fluorouracil (FU), fluorodeoxyuridine, cis-diaminechloroplatinum(II) (C-DDP), paclitaxel, docetaxel, and vinorelbine.
Demonstration of myocardial ischemia by an internal loop recorder.

VLAY, S.C., et al.: Demonstration of Myocardial Ischemia by an Internal Loop Recorder. An internal loop recorder (ILR) implanted to evaluate syncope was activated during an episode of chest pain. Analysis of the recorded event revealed a marked increase in the amount of ST-segment depression over baseline. In addition to rhythm analysis, the ILR may be able to assess myocardial ischemia. Further refinements of filtering may make analysis more accurate.
Sex differences in jealousy in response to infidelity: Evaluation of demographic moderators in a national random sample

Abstract Studies examining sex differences in jealousy have often relied on student samples and were restricted to the evaluation of a selected few moderators. In this study, a nationally representative survey of American households was presented with either an actual or a hypothetical infidelity scenario (which appeared as either a forced choice or as continuous measures). Significant sex differences only emerged for forced choice measures and not for continuous measures. Importantly, this effect appeared most strongly in participants reporting reactions to an actual infidelity. We also explored a number of potential moderators of this effect. These moderators were more influential for the hypothetical than for the actual infidelity scenario. Exploratory analysis of additional demographic variables was conducted.
Does phenobarbital protect against trimethyltin-induced neuropathology of limbic structures?

Abstract Because of the similarity in the pattern of limbic sites damaged by both compounds, it has been suggested that trimethyltin (TMT) may be an excitotoxin like kainic acid (KA). KA produces seizures which eventually result in neuronal damage similar to that found in epilepsy. Anticonvulsants reduce both the seizures and pathology associated with KA. Because TMT may also produce seizures, we undertook to determine whether or not some of the TMT-induced limbic neuropathology could result from seizure activity. To do this, a single dose of TMT chloride (either 7.5 or 15 mg/ kg) was given per os to rats, and then phenobarbital (30 mg/kg) was administered subcutaneously in repeated doses. Treatment with phenobarbital did not prevent pathologic changes in the hippocampus, dentate gyrus, and pyriform or prepyriform cortex. Since phenobarbital did not protect against TMT-induced neuronal damage, as it has been reported by others to protect against KA-induced damage, the present findings suggest that these two toxicants probably produce hippocampal pathology via different mechanisms and that the TMT-induced pathologic changes do not require sustained electrical seizure activity.
"Applied Constructivism" for User Documentation: Alternatives to Conventional Task Orientation.

This inquiry explores the practical implications of constructivist theory for documentation that is targeted to complex tasks and experienced users (users who are less than experts but more than novices). It argues that current task-oriented documentation falls short in addressing these tasks and users and examines the contributions that constructivism can make, contributions that will lead to documentation that differs in kind not just degree from conventional task-oriented manuals and help systems. This inquiry synthesizes the following four themes from constructivist theory and analyzes their relevance to documentation development: (1) changing the object of instruction to “activity in context,” (2) shaping instruction around problems experienced by users in work contexts, (3) highlighting users' social stock of knowledge, and (4) adopting a rhetoric of problem-based instruction expressed through cases. Examples are given from current efforts in interface and instructional design that writers may adapt...
Cytokeratin 7 and 20 expression in epithelioid sarcoma.

Background: Epithelioid sarcoma (ES) is a rare malignant soft tissue tumor of uncertain histogenesis that arises predominantly in the extremities of young adults. Immunohistochemically, the neoplastic cells are typically positive for vimentin, low molecular weight cytokeratin (CAM5.2) and epithelial membrane antigen (EMA). Method: We examined eight cases of ES from seven different patients. All cases were studied with immunohistochemistry for EMA, CAM5.2 (keratin 8 and 18), 34BE12 (keratins 1, 5, 10 and 14/15), cytokeratins 7 and 20 (CK7, CK20), and CD34. Results: The average patient age was 53 (range 43–76) and the male:female ratio was 5:2. The location was the upper extremity in five tumors, the lower extremity, the perineum, and the paraspinal soft tissue in one tumor each. All cases contained predominantly epithelioid cells, but spindle cells were also present in three cases. All cases contained areas of geographic necrosis. CAM5.2 was strongly positive in seven tumors and focally positive in one (8/8). EMA was diffusely positive in two cases and focally positive in five cases (7/8). CD34 was diffusely positive in 3/8 cases. 34BE12 was diffusely positive in one case and focally positive in two others (3/8). CK7 was diffusely positive in one case and focally positive in another (2/8). CK20 was negative in all cases (0/8). All cases tested were positive for vimentin (6/6), 2 cases were focally positive for HHF35 (2/5), and all cases tested were negative for S-100 protein (0/7). Conclusions: In addition to the known immunoreactivity for CAM5.2 and EMA, there is positivity for CK7 and 34BE12 in a small proportion of cases. None of the cases expressed CK20. This immunophenotypic profile suggests that ES is more similar to carcinoma and synovial sarcoma than to other soft tissue tumors, and may be of diagnostic utility.
Constructing academic alter-egos: identity issues in a blog-based community

Choosing to interact with others in an online forum provides an opportunity for exploring one’s own identity. With each new group joined, a person must make decisions about self-presentation and react to an audience. Such decisions continue as social interactions occur and relationships develop. This paper discusses how bloggers who have affiliated with each other to form a loosely knit community develop largely pseudonymous identities along with norms surrounding the development and performance of identity. The study is ethnographic and longitudinal, examining a community of academics who blog and comment alongside each other in a diaristic manner. Focal areas include blog elements through which identity may be expressed, namely (1) Name and blog title; (2) Profiles; (3) Post content; (4) Voice; (5) Affiliations; and (6) Visual design; the effect of pseudonyms on blog authors and readers; and how issues of privacy and trust are manifest in the community.
Proenkephalin A-derived peptide E and its fragments alter opioid contractility in the small intestine.

Abstract The human and canine small intestine exhibit increased contractility when exposed to exogenous or endogenous opioid peptides. The response of the canine small intestine to the proenkephalin A-derived peptide, peptide E and related processing fragments [Met 5 ]enkephalin, BAM-12P, BAM-18P and BAM-22P was investigated by administering each peptide to isolated, small intestine segments which causes a significant increase in intraluminal pressure. Concentration-response curves from intraarterial bolus administration of peptide E, [Met 5 ]enkephalin, BAM-12P, BAM-18P and BAM-22P showed decreasing efficacy with decreasing amino acid chain length while naloxone (305 nM) significantly antagonized the response. Results using the classical guinea pig ileum/myenteric plexus longitudinal muscle and mouse vas deferens bioassays with specific opioid receptor antagonists provide evidence that peptide E and BAM-18P are relatively specific to the μ opioid receptor, [Met 5 ]enkephalin is more δ specific, BAM-22P is both μ and κ specific and BAM-12P is κ opioid receptor specific. These studies demonstrate that locally released (and possibly circulating) peptide E and related processing fragments increase contractility in the small intestine and may be active through more than a single receptor mechanism, particularly the μ receptor.
Signaling by purinergic receptors and channels in the pituitary gland

Abstract Adenosine 5′-triphosphate is frequently released by cells and acts as an agonist for G protein-coupled P2Y receptors and ligand-gated P2X cationic channels in numerous tissues. The breakdown of ATP by ectonucleotidases not only terminates its extracellular messenger functions, but also provides a pathway for the generation of two additional agonists: adenosine 5′-diphosphate, acting via some P2Y receptors, and adenosine, a native agonist for G protein-coupled adenosine receptors. In the pituitary gland, adenosine 5′-triphosphate is released from the endings of magnocellular hypothalamic neurons and by anterior pituitary cells through pathway(s) that are still not well characterized. This gland also expresses several members of each family of purinergic receptors. P2X and adenosine receptors are co-expressed in the somata and nerve terminals of vasopressin-releasing neurons as well as in some secretory pituitary cells. P2X receptors stimulate electrical activity and modulate InsP 3 -dependent calcium release from intracellular stores, whereas adenosine receptors terminate electrical activity. Calcium-mobilizing P2Y receptors are expressed in pituicytes, folliculo-stellate cells and some secretory cells of the anterior pituitary.
The Contribution of Emotion Regulation Difficulties to Risky Sexual Behavior within a Sample of Patients in Residential Substance Abuse Treatment

The present study examined the unique contribution of emotion regulation difficulties to past-year risky sexual behavior (RSB) among substance use disorder (SUD) patients (above and beyond other known RSB risk factors). A sample of 177 SUD patients completed a series of questionnaires. At the zero-order level, emotion regulation difficulties, were significantly positively associated with the number of commercial sexual (i.e., the exchange of sex for drugs or money) partners with which penetrative sex occurred and significantly negatively associated with the likelihood of using a condom when having sex with a commercial partner under the influence of drugs. Emotion regulation difficulties also significantly predicted these RSB indices above and beyond other RSB risk factors, including demographics, depression, sensation seeking, traumatic exposure, and substance use severity. The specific emotion regulation difficulty of lack of emotional clarity emerged as a unique predictor of RSB. The implications of these findings for understanding motivations for RSB and developing targeted interventions for RSB among SUD patients are discussed.
Mutations in DNA Methyltransferase (DNMT3A) Observed in Acute Myeloid Leukemia Patients Disrupt Processive Methylation

DNA methylation is a key regulator of gene expression and changes in DNA methylation occur early in tumorigenesis. Mutations in the de novo DNA methyltransferase gene, DNMT3A, frequently occur in adult acute myeloid leukemia patients with poor prognoses. Most of the mutations occur within the dimer or tetramer interface, including Arg-882. We have identified that the most prevalent mutation, R882H, and three additional mutants along the tetramer interface disrupt tetramerization. The processive methylation of multiple CpG sites is disrupted when tetramerization is eliminated. Our results provide a possible mechanism that accounts for how DNMT3A mutations may contribute to oncogenesis and its progression.
Autoamputation of an extranasopharyngeal angiofibroma of the nasal septum

Summary Angiofibromas arising from outside the nasopharynx are rare but have been reported from a variety of sites in the head and neck. We report the case of an angiofibroma originating from the nasal septum and which underwent spontaneous autoamputation prior to intervention.
Comparison of Organic and Chemical Soil Amendments Used in the Reforestation of a Harsh Sierra Nevada Site

A comparison of a composted organic amendment, a controlled-release fertilizer, and induced mycorrhizal inoculation as affecting the establishment and nutrition of bareroot Jeffrey pine (Pinus jeffreyi Grev. & Balf.) was conducted on a Sierra Nevada surface mine. The soil amendments were applied at outplanting to the backfill of augered planting holes, with a low rate of 8 g and a high rate of 16 g per seedling for the fertilizer, Gromax 21-6-2 + Minors, whereas a single rate of 2.0 L was used for organic matter. Colonization by Pisolithus tinctorius (Pers.) Coker & Couch was induced by coating the root systems with basidiospores suspended in a gel carrier. The organic amendment especially, but also mycorrhizal inoculation, caused substantial seedling mortality, whereas survival was unaffected by controlled-release fertilization. Gromax applied at the high rate produced a 74% increase in shoot volume after three growing seasons, whereas the organic amendment reduced volume by 28%. Growth was unaffected by mycorrhizal treatment. The growth response to the 16-g Gromax application probably reflected enhanced N, P, and K nutrition and decreased concentrations of potentially toxic metallic elements, including Mn and Al among others, as revealed through foliar analysis. Because they were accompanied by growth reduction, nutritional responses to the organic amendment, which involved both macronutrients and trace elements, were of little consequence. Impaired water relations may account for the poor response to this amendment. Likewise, nutritional responses to mycorrhizal inoculation produced no discernible benefit in terms of seedling performance. An inoculation procedure that failed to induce substantially greater P. tinctorius colonization in inoculated than uninoculated seedlings, and that may have also impaired water relations, likely explains this result. Overall, these findings indicate that further research is needed before either the organic amendment or the mycorrhizal inoculation procedure used here can be used in forest restoration efforts on dry sites.
Experimental Controlled-NOT Logic Gate for Single Photons in the Coincidence Basis

We report a proof-of-principle demonstration of a probabilistic controlled-NOT gate for single photons. Single-photon control and target qubits were mixed with a single ancilla photon in a device constructed using only linear optical elements. The successful operation of the controlled-NOT gate relied on post-selected three-photon interference effects, which required the detection of the photons in the output modes.
Retrieving Soil Water Contents from Soil Temperature Measurements by Using Linear Regression

A simple linear regression method is developed to retrieve daily averaged soil water content from diurnal variations of soil temperature measured at three or more depths. The method is applied to Oklahoma Mesonet soil temperature data collected at the depths of 5, 10, and 30 cm during 11–20 June 1995. The retrieved bulk soil water contents are compared with direct measurements for one pair of nearly collocated Mesonet and ARM stations and also compared with the retrievals of a previous method at 14 enhanced Oklahoma Mesonet stations. The results show that the current method gives more persistent retrievals than the previous method. The method is also applied to Oklahoma Mesonet soil temperature data collected at the depths of 5, 25, 60, and 75 cm from the Norman site during 20–30 July 1998 and 1–31 July 2000. The retrieved soil water contents are verified by collocated soil water content measurements with rms differences smaller than the soil water observation error (0.05 m3 m−3). The retrievals are found to be moderately sensitive to random errors (±0.1 K) in the soil temperature observations and errors in the soil type specifications.
A Distributed Bulk-Oxide Trap Model for $\hbox{Al}_{2} \hbox{O}_{3}$ InGaAs MOS Devices

This paper presents a distributed circuit model for bulk-oxide traps based on tunneling between the semiconductor surface and trap states in the gate dielectric film. The model is analytically solved at dc. It is shown that the distributed bulk-oxide trap model correctly depicts the frequency dispersion in the capacitance- and conductance-voltage data of Al2O3-InGaAs MOS devices that do not fit the conventional interface state model. The slope degradation or stretch-out of the measured capacitance-voltage curve near flatband can be also explained by the distributed bulk-oxide trap model.
Nano- and micromechanical properties of hierarchical biological materials and tissues

The mechanical properties of biological materials have been the focal point of extensive studies over the past decades, leading to formation of a new research field that intimately connects biology, chemistry and materials science. Significant advances have been made in many disciplines and research areas, ranging throughout a variety of material scales, from atomistic, molecular up to continuum scales. Experimental studies are now carried out with molecular precision, including investigations of how molecular defects such as protein mutations or protein knockout influence larger length- and time-scales. Simulation studies of biological materials now range from electronic structure calculations of DNA, molecular simulations of proteins and biomolecules like actin and tubulin to continuum theories of bone and collagenous tissues. The integration of predictive numerical studies with experimental methods represents a new frontier in materials research. The field is at a turning point when major breakthroughs in the understanding, synthesis, control and analysis of complex biological systems emerge. Here we provide a brief perspective of the state of this field and outline new research directions.
Nightside polar rain aurora boundary gap and its applications for magnetotail reconnection

[1] Polar rain electrons with energy around 1 keV occasionally fill the polar cap ionosphere. Their energy flux is high enough to produce detectable auroral emissions, called polar rain aurora (PRA). We report a PRA event on 2 August 2002 and the estimation of the magnetotail reconnection location and size from the PRA boundary. The distinguishing feature of this event identified from the TIMED/GUVI data is an emission depletion gap between PRA and auroral oval. The size of the gap is about 2° in latitude and extended from the dusk sector (17:00 MLT) to the premidnight sector (22:00 MLT). This gap coincides with the electron flux gap in the DMSP electron energy flux data. The electron flux data show the existence of energy dispersion at the gap. These GUVI and DMSP observations support the idea that the gap is very likely due to a magnetic reconnection in the magnetotail that blocks the solar wind electron entry into the polar ionosphere. Based on the electron energy dispersion, the nightside X line is estimated to be at X = −50 to −60 RE, which is consistent with results from other studies. The gap extends from the nightside to the duskside and presumably to the dawnside. This new information suggests that the extension of the tail X line over the entire plasma sheet in the dawn-dusk direction under a strongly southward IMF (Bz ∼ −10 nT) and the curved nature of the X line.
Characteristics of nanoscopic Au band electrodes

Abstract Gold band electrodes with widths ranging from 3 to 150 nm are used to investigate the voltammetric response of a series of substituted ferrocenes in non-aqueous electrolyte. The Au electrodes are fabricated by insulating, with an epoxy, all but the edge of an evaporated Au film deposited onto a silane-modified glass substrate. Plots of normalized limiting current for each ferrocene derivative as a function of normalized electrode width reveal a negative response from traditional theoretical predictions. The theory used for the band electrodes is based on semiinfinite diffusion of the ferrocenes to a hemicylindrical electrode. The observed negative responses for electrodes less than 50 nm in width are explained by effects that become important when the sizes of the electrode and redox species are comparable. Concerns regarding the real surface area of the band electrodes are addressed by labeling of the exposed Au of the nanoband electrode with a ferrocene-tagged alkanethiol and measurements of double-layer capacitance. These studies indicate that roughly 20–500 times more area is exposed than that calculated from the nominal width and length of the bands, even though X-ray diffraction and stylus profilometry determinations of Au thickness are in agreement with those found by quartz crystal microgravimetry during evaporation of the Au films. Scanning electron microscopy studies of the epoxy ∣ Au ∣ glass interface point to insufficient insulation of the Au by the epoxy as the result of defects.
Toward an understanding of the role of notochordal cells in the adult intervertebral disc: From discord to accord

The goal of this mini-review is to address the long standing argument that the pathogenesis of disc disease is due to the loss and/or the replacement of the notochordal cells by other cell types. We contend that, although cells of different size and morphology exist, there is no strong evidence to support the view that the nucleus pulposus contains cells of distinct lineages. Based on lineage mapping studies and studies of other notochordal markers, we hypothesize that in all animals, including human, nucleus pulposus retains notochordal cells throughout life. Moreover, all cells including chondrocyte-like cells are derived from notochordal precursors, and variations in morphology and size are representative of different stages of maturation, and or, function. Thus, the most critical choice for a suitable animal model should relate more to the anatomical and mechanical characteristics of the motion segment than concerns of cell loss and replacement by non-notochordal cells.
Increased high-affinity nicotinic receptor-binding in rats exposed to lead during development.

Abstract Receptor autoradiography and membrane radioligand-binding assays were used to determine the expression of nicotinic cholinergic receptors in the brains of weanling rats exposed to low-levels of lead (Pb) during development. Nicotinic receptors were identified with the frog toxin epibatidine (EB) that binds with high affinity to a variety of receptors containing α and β subunits. Rat pups were exposed to Pb from their mothers given 750-ppm Pb in the diet beginning on gestational day 0 through postnatal day (PN) 21. Blood Pb levels ranged from 36.5 to 46.5 μg/dl in the PN21 pups, and this exposure did not alter their body weight when compared to control rats. Several brain regions identified by autoradiographic studies as having significant binding of EB were dissected from control and Pb-treated pups and used in saturation-binding experiments with membrane preparations to determine the affinity constant ( K d ) and maximal-binding capacity ( B max ) of [ 3 H]EB. Results indicate that the B max of [ 3 H]EB was increased in several brain regions in Pb-treated rat pups, without a significant effect on K d estimates. [ 3 H]EB-binding to membranes from untreated rats was not affected by in vitro exposure to 20-μM Pb, indicating that the effect of Pb on [ 3 H]EB-binding in vivo was not likely due to direct influence of free Pb remaining in the tissue at the time of assay. The data therefore suggest that expression of nicotinic receptors that bind [ 3 H]EB were increased by developmental exposure to Pb. Several possible mechanisms for these effects and the potential toxicological significance are discussed.
Comparison of structural effects on Eu(III) complexes with cyclohexyl and benzene polycarboxylic acids

Abstract The thermodynamics ( β , Δ H , Δ S ) of complexation, the residual hydration of the complexed metal ion and the metal-ligand coordination number of the complexes formed by interaction of Eu(III) with 1, 3, 5-cyclohexyltricarboxylic acid, 1, 2, 3- and 1, 2, 4-benzenetricarboxylic acids, cyclohexylhexacarboxylic (CHHS) acid and benzenehexacarboxylic (mellitic) acid have been studied. The 1, 3, 5-cyclohexyltricarboxylate ligand binds by only a single carboxylate while the 1, 2, 3-, and 1, 2, 4-benzene tricarboxylate ligands bind via two carboxylates. The mellitate complexes were found to have bidentate chelation and a residual hydration number, N H 2 O , complexed Eu(III) of ca. 7 in acid-to-neutral solutions. By contrast, in the Eu-CHHS complexation, the coordination number for the ligand binding, CN L , was 2 in acidic to neutral in basic solutions while the residual hydration number of the Eu(III) changed from 6 to 7 in acidic solutions to 2.5 in alkaline solutions. This is interpreted to indicate the formation of [Eu(CHHS)(OH)(H 2 O) 2 ] 4− . The data are discussed in terms of ligand steric effects upon complexation.
Bankers on the board and the debt ratio of firms

Abstract We investigate the impact that bankers on the board have upon a firm's debt ratio, debt to total capital, 1 year subsequent to their appointment. We find that the presence of lending bankers on a firm's board negatively affects the debt ratio, while the impact of non-lending bankers varies with the firm's probability of financial distress. The results suggest that non-lending bankers provide expertise and certification for distressed firms while exercising a monitoring role for non-distressed firms. In contrast, the results suggest that lenders on the board exercise a monitoring role independent of the firm's financial distress. When combined with established findings in the literature, we conclude that there may be two ways to avoid conflict between a board-appointed banker's fiduciary responsibility and the interests of her bank. When the potential for conflict is high, lenders may forgo board positions, while non-lending bankers may merely alter their role on the board.
Bile salt-dependent, neutral cholesteryl ester hydrolase of rat liver: possible relationship with pancreatic cholesteryl ester hydrolase.

Abstract Homogenates of the livers of outbred, Sprague-Dawley rats contain a neutral cholesteryl ester hydrolase activity that requires millimolar concentrations of bile salts for maximal activity. Previous studies showed that this activity had the unusual property of being highly variable among individual rats. The present studies were conducted to define further the nature of this enzymic activity and to explore the possible basis for the variability. Individual liver homogenates from inbred Fisher-344 rats showed the same range and magnitude of activity as outbred rats, suggesting that genetic heterogeneity was not a factor in determining the enzyme activity. Tissue distribution studies showed the presence of a very similar enzyme activity in serum, bile and intestinal homogenates, with the specific activity in intestine being 25–500-times greater than that in liver. Moreover, the enzymic properties of the activity in serum, liver and intestine were identical to those of purified rat pancreatic cholesteryl ester hydrolase (EC 3.1.1.13). Monospecific, anti-pancreatic hydrolase IgG specifically and completely inhibited the cholesteryl ester hydrolase activity in rat serum, intestine and liver. The results raise the possibility that the neutral, bile salt-dependent cholesteryl ester hydrolase activity of rat liver homogenates may be due to the uptake of enzyme originating in the pancreas. This, in turn, may explain the dramatic variation in activity observed among individual rat livers.
Leukemia virus long terminal repeat activates NFκB pathway by a TLR3-dependent mechanism

Abstract The long terminal repeat (LTR) region of leukemia viruses plays a critical role in tissue tropism and pathogenic potential of the viruses. We have previously reported that U3-LTR from Moloney murine and feline leukemia viruses (Mo-MuLV and FeLV) upregulates specific cellular genes in trans in an integration-independent way. The U3-LTR region necessary for this action does not encode a protein but instead makes a specific RNA transcript. Because several cellular genes transactivated by the U3-LTR can also be activated by NFκB, and because the antiapoptotic and growth promoting activities of NFκB have been implicated in leukemogenesis, we investigated whether FeLV U3-LTR can activate NFκB signaling. Here, we demonstrate that FeLV U3-LTR indeed upregulates the NFκB signaling pathway via activation of Ras-Raf-IκB kinase (IKK) and degradation of IκB. LTR-mediated transcriptional activation of genes did not require new protein synthesis suggesting an active role of the LTR transcript in the process. Using Toll-like receptor (TLR) deficient HEK293 cells and PKR −/− mouse embryo fibroblasts, we further demonstrate that although dsRNA-activated protein kinase R (PKR) is not necessary, TLR3 is required for the activation of NFκB by the LTR. Our study thus demonstrates involvement of a TLR3-dependent but PKR-independent dsRNA-mediated signaling pathway for NFκB activation and thus provides a new mechanistic explanation of LTR-mediated cellular gene transactivation.
Using Organizational Collaboration and Community Partnerships to Transition Families from Homelessness to Home Ownership: The HomeBuy5 Program

For more than a decade, the HomeBuy5 Program has successfully helped families who were homeless find an apartment, while working with them to develop a plan to move from homelessness to homeownership. This article provides an historical overview of how the program developed and evolved, a detailed discussion of the program's process and structure, the role of organizational collaboration and community partners, and demographic information on the families that have been served. It is argued that this program can be a prototype for other communities as they increase their efforts to eliminate homelessness.
For the birds: challenging wilderness in the Everglades

This paper examines the wilderness of the Everglades National Park (ENP). This wilderness challenges both the concept and history of wilderness in the United States. While the modern concept of wilderness formed in the 1920s revolved around wilderness as a recreational, aesthetic, and spiritual resource, the Everglades was protected for biocentric reasons, a rationale for preservation typically thought of as a product of modern environmentalism. This new ecological rationale for wilderness was necessary largely due to the nature of the Everglades itself. Conservationists traditionally saw little anthropocentric value in wetlands; therefore, activists seeking to protect the Everglades had to utilize new biocentric rationales to argue for its preservation. Because this wilderness is composed of wetlands and aquatic areas, traditional definitions of wilderness have little application in the Everglades. Modern definitions of wilderness revolve around roadlessness and the absence of human-built constructs, but these definitions, particularly roadlessness, have little application in the Everglades. This wilderness yet also illustrates the flexibility of wilderness and shows that ecological values, rather than just romantic notions of unspoilt nature, need to be considered when defining and delineating wilderness. Finally, this paper examines how the human/nature dichotomy that lies at the foundation of wilderness is an obvious fiction in the Everglades.
Children's Language Learning: An Interactionist Perspective

This review of children's language learning considers historical accounts of acquisition and individual variation, recent advances in methods for studying language learning, research on genetic and environmental input that have contributed to the interactionist perspective, and the relevance of cross-disciplinary work on language disorders and the biology of learning to future theories. It concludes that the study of children's language development is converging on an interactionist perspective of how children learn to talk, incorporating the contributions of both nature and nurture to emergent, functional language systems. Language learning is viewed as an integration of learning in multiple domains.
The Passive Optical Sample Assembly (POSA): I Experiment: First Flight Results and Conclusions

The Passive Optical Sample Assembly-I (POSA-I), part of the Mir Environmental Effects Payload (MEEP), was designed to study the combined effects of contamination, atomic oxygen, ultraviolet radiation, vacuum, thermal cycling, and other constituents of the space environment on spacecraft materials. The MEEP program is a Phase 1 International Space Station Risk Mitigation Experiment. SSP 30258 "Thermal Control Architectural Control Document", section 3.1.2 requires that International Space Station (ISS) external materials meet performance requirements when exposed to the external environment as defined in SSP 30426, "Space Station External Contamination Control Requirements." Contamination control documents call for less than 3 x 10(exp -7) gm/sq cm/yr of molecular contamination on a surface at 300 K at the Prime Measurement Points during quiescent periods and less than 1 x 10(exp-6) gm/sq cm/yr during non-quiescent periods. Assuming a density of 1.0 g/cu cm for the contaminant, this is roughly equivalent to 30-100 A per year. A previous Mir flight experiment (Guillaumon et al. 1991) measured 321-716 A per year. Were this to happen on ISS, the radiators would reach end-of-life properties much sooner than the planned 10 years. Therefore, POSA was proposed to expose ISS-baselined materials (such as Z93 white thermal control paint and chromic acid anodized aluminum) to the Mir environment and determine not only the level of contamination from an orbiting, active space station but also the effect of contamination on thermal optical properties. POSA-I consisted of nearly 400 samples of various candidate materials for ISS. Paint samples flown included Z-93 and YB-71 white thermal control paints and a new inorganic bright yellow paint htat can be utilized for astronaut visual aids.
Adding software testing to programming assignments

This tutorial provides a practical introduction to how one can incorporate software testing activities as a regular part of programming assignments, supported by live demonstrations, with a special focus on early introduction in CS1 and/or CS2 courses. It presents five different models for how one can incorporate testing into assignments, provides examples of each technique, and discusses the corresponding advantages and disadvantages. The focus is on unit testing, test-driven development, and incremental testing, all of which work well in a classroom environment. Examples will use Java, although participant discussion regarding support in other languages such as Python and C++ is welcome. Approaches to assessment- using testing to assess student code, assessing tests that students write, and automated grading-are all discussed. A live demonstration of automatic assignment grading based on student-written tests is included. Advice for writing “testable” assignments is given. Participant discussions are encouraged.
Permeability of the blood-brain barrier to melanocortins

Adrenocorticotropin (ACTH)-related compounds, termed melanocortins, produce a large number of effects on the central nervous system (CNS) after their peripheral administration. Some of the CNS effects of ACTH are mediated through the release of glucocorticoids from the adrenal gland, but there are fragments and analogues of ACTH that do not act on the adrenals. This raises the possibility that some blood-borne melanocortins may be acting directly on the brain, which would necessitate their crossing the blood-brain barrier (BBB). We review here the literature showing that melanocortins can affect the BBB in several ways, including an alteration of the permeability of the BBB to other substances.
Efficiency measures for multiplant firms

Previous studies of output-based efficiency measures make no distinction between plant data and firm data. In this paper two new efficiency measures are proposed and characterized in the context of multiplant firms. An empirical example is given to illustrate the two measures.
Catalyst metal-support interactions: Rutherford backscattering spectrometry applied to discontinuous films

Abstract Catalyst surfaces are generally prepared with finely divided metal particles dispersed over a rough porous ceramic “support” substrate. Application of standard analysis techniques to such inhomogenous surfaces has been regarded as virtually impossible. However, the powerful effects of supposedly passive support materials on the performance of catalyst surfaces have led to a great need to understand the “Strong Metal-Support Interactions” (SMSI) in these materials. We have demonstrated that Rutherford backscattering spectrometry (RBS) can be applied to even such difficult questions. In the Present work, the metal/ceramic systems were modeled with thin films of Pt or Rh deposited on single-crystal substrates of Al2O3 or TiO2 and subjected to extended heat treatment in various atmospheres. The metals do not in general “wet” the support surface, and hence they break up into islands. Nevertheless, careful RBS analysis of composition profiles for these discontinuous layers, together with electron microscopy, has enabled us to unravel a complex chain of diffusion/reaction processes which seems to account for the SMSI effects in these systems.
A multicenter experience of the management of collapsed thoracic endografts

Objectives Thoracic endograft collapse after thoracic endovascular aortic repair (TEVAR) is a potentially devastating complication. This study evaluates the management of thoracic stent graft collapse. Methods A multicenter review of thoracic stent graft collapse was performed from 2005 to 2009. Diagnosis and preoperative planning was performed by computed tomography angiography (CTA). Outcome measures included success of endovascular salvage, postoperative complications, and conversion to open repair. Results Eleven patients (10 men) with thoracic endograft collapse were identified. Mean age was 41.2 years old (range, 21-66 years). Indications for the index TEVAR were traumatic aortic transections in 8 patients and acute type B dissections in 3 patients. All were initially treated with the TAG endoprosthesis (Gore and Associates, Flagstaff, Ariz). The median duration from initial repair to diagnosis of collapse was 9 days (range, 1 day-38 months). All collapses were initially treated by endovascular means using another TAG device in 7 patients, a Talent (Medtronic, Santa Rosa, Calif) thoracic stent graft in 3 patients, and a Palmaz (Cordis Endovascular, Warren, NJ) stent in 1 patient. In 1 patient, the secondary TAG did not resolve the collapse and required a Palmaz stent placement. Technical success rate was 91%, while re-expansion of the collapsed endograft was achieved in all patients. Early and late complications were observed in 3 patients. Delayed (>30 days) open conversion with device explantation was performed for an aortoesophageal fistula, physiological aortic coarctation, and prevention of a recurrent collapse in 1 patient each. There were no perioperative deaths or recurrent collapses. Conclusion Endograft collapse can be successfully managed by endovascular techniques in most cases. Redo-TEVAR using high radial force devices should be considered the initial treatment of choice. Late endograft-related complications after treatment of collapsed endografts are not uncommon and can be safely managed by open conversion.