cssi/SciSciGPT-SciSciNet huggingface dataset:
Nonlinear Model Reduction and Control of Particulate Processes

This chapter focuses on nonlinear model reduction and feedback control of particulate processes for which the effect of spatial variations can be safely neglected. Using population balances, such processes can be adequately described by a class of nonlinear partial integro-differential equation systems. The objective is to develop a general and rigorous method for the derivation of low-order approximations of the distributed parameter process model and the synthesis of practically implementable (i.e., low-order) nonlinear model-based feedback controllers that enforce the desired stability and performance specifications (such as PSDs with desired total mass and mean particle size) in the closed-loop system.
Polynomial-Time Computability

This chapter concerns the running time that a program might require. It introduces the concepts and describes the ideas behind the results. The “industry standard” conventions are to use Turing machines and binary numerals. Register machines make use of the material already developed for register machines. The definition of a Turing machine demands that a machine's table of quintuples be unambiguous, that is, that no two different quintuples have the same first two components. There is a clear analogy between computable and recursively enumerable sets. Two reasonable measurements of complexity are time and space. These two measurements are related.
In vitro cytotoxicity of ABT-751, a novel tubulin inhibitor, in pediatric solid tumor cell lines

4351 ABT-751 is an orally bioavailable sulfonamide that is not a substrate for P-glycoprotein and which binds the colchicine binding site of β-tubulin to inhibit tubulin polymerization. A phase I trial in children with refractory solid tumors suggests selective activity in neuroblastoma. The ABT-751 steady state plasma concentration is 11 μM in children at the maximum tolerated dose. We assessed the in vitrocytotoxicity of ABT-751 and vincristine (VCR), a vinca alkaloid tubulin inhibitor, and evaluated their effect on tubulin polymerization in eight pediatric tumor cell lines, including neuroblastoma (SKNAS, SKNDZ, KCNR), Ewing’s sarcoma (LD, TC-71), osteosarcoma (HOS), medulloblastoma (Daoy), and rhabdomyosarcoma (RD). 5–10,000 cells/well were incubated for 24 hours then exposed to vehicle, ABT-751 (0.1–100 μM) or VCR (0.1–1000 nM) for 72 hours. Cell survival was measured with the standard sulforhodamine B (SRB) assay and with the ACEA RT-CES, which continuously monitors changes in electrical impedance of adherent cells over time. Cell survival, which is expressed as percent of vehicle control, was plotted as a function of drug concentration. IC50’s were estimated from the cell survival curves. Tubulin polymerization was assessed before and after drug exposure by western blots using antibodies specific for post-translational modifications that occur during tubulin polymerization/depolymerization. The ABT-751 IC50 was 0.7–2.3 μM and 0.8–6.0 μM in neuroblastoma and non-neuroblastoma cell lines, respectively. The VCR IC50 was 1.6 –5.7 nM and 1.6–6.6 nM in neuroblastoma and non-neuroblastoma cells lines, respectively. The difference between the ABT-751 IC50 in neuroblastoma and other solid tumor cell lines was not significant (P = 0.14). No significant difference was observed between IC50’s determined using the SRB assay and ACEA RT-CES method (P = 0.2). Following ABT-751 or VCR exposure, polymerized tubulin was decreased in a concentration dependent manner in all cell lines. IC50’s generated using the ACEA RT CES cell survival assay were similar to results from the standard SRB assay. ABT-751 is cytotoxic at concentrations that are tolerable in children. Although not statistically significant, a trend of increased activity of ABT-751 against neuroblastoma cell lines as compared to the activity exhibited in other pediatric solid tumor cell lines was observed. Dose-dependent effects on tubulin polymerization were observed in pediatric solid tumor cell lines and may serve as a surrogate marker.
Marijuana Legalization: Lessons from the 2012 State Proposals

On November 6, 2012, citizens in three U.S. states will vote on whether to legalize production, distribution, possession, and sale of marijuana for general—not just medical—use. Legalization is typically imagined as an up or down, binary choice. However, a comparison of 17 legalization proposals actively discussed in various U.S. states in 2012 reveals differences that would have important consequences for price, availability, arrest-risk, use, and, hence, health. This paper divides the proposals into three broad categories and assesses their political feasibility. It then addresses the implications of state-level legalization, and possible federal responses to it, for retail price, tax revenues, and spill-over effects in other states where marijuana would remain illegal.
Towards in silico models of decomplexification in human endotoxemia

Abstract Heart rate (HR) variability (HRV) is an important variable in determining the state of a critically ill patient. This motivates the quantitative understanding of the mechanisms giving rise to changes in HRV, particularly in the context of critical illness. Human endotoxemia, a clinical model of systemic inflammation, has been modeled previously to characterize its complex dynamics. This model is extended to incorporate a semi-mechanistic model of signal transduction leading from the well-established processes at the cellular and molecular levels in the inflammatory response to systemic changes in HR and HRV as governed by the autonomic nervous system's response to inflammation. This is accomplished with an integral pulse frequency modulation model that translates the continuous, deterministic model dynamics into a series of discrete, variable heart beats. Thus, homeostatic variability and the mechanisms leading from cellular processes to systemic changes in variability under endotoxemia are assessed.
Intra-amniotic administration of prostaglandin F2α to induce therapeutic abortion

Abstract Forty-one physically healthy gravid women between 13 and 20 weeks' gestation were treated with intra-amniotic injections of prostaglandin in F 2α (PGF 2α ) by one of two dosage schedules to induce therapeutic abortion. The results were compared over a 48 hour period. In one group, 15 mg. of PGF 2α was injected initially, and this dose was repeated after 24 hours in those patients who failed to abort. In the second group 25 mg. of PGF 2α was administered by the same schedule. The results obtained by this latter method were superior to those achieved by either the 15 mg. schedule or by hypertonic saline instillation. Patients premedicated with prochlorperazine had less vomiting. Multiparous patients had higher rates of abortion and aborted in a significantly shorter period of time than nulliparous patients. Although the 25 mg. dosage schedule is more effective than hypertonic saline instillation, it is likely that still more effective intra-amniotic schedules will be developed.
Identification of essential histidine residues in rat type I iodothyronine deiodinase.

Abstract Deiodination is required for conversion of thyroxine, the inactive prohormone secreted by the thyroid gland, to 3,5,3'-triiodothyronine, the biologically active thyroid hormone. The principal enzyme catalyzing this reaction, Type I iodothyronine 5' deiodinase, was shown recently to contain the amino acid, selenocysteine, and site-directed mutagenesis showed that this amino acid confers the biochemical properties characteristic of this enzyme. Previous studies suggest that a histidine residue may also be critical for activity. To further our understanding of the biochemical mechanism of this reaction, we have used in vitro mutagenesis to examine the contribution of each of the 4 histidines in this enzyme to the deiodination process. Two of the histidines (185 and 253) are not involved in deiodination, as their removal had no effect on activity. Mutagenesis of histidine 158 resulted in complete loss of activity, suggesting a role in either protein conformation or catalysis. The most informative results were obtained from the studies of histidine 174. Mutagenesis of this histidine to asparagine or glutamine altered reactivity with substrate and reduced inhibition by diethylpyrocarbonate and rose bengal. These results demonstrate that histidine 174 is critical to function and appears to be involved in binding of hormone.
Race, Ethnicity, Crime, and Immigration

Unwarranted disparities in criminal justice system treatment and discrimination affect members of disadvantaged minority groups in every country. For some groups, including aboriginal residents of English-speaking countries, Afro-Americans, and Afro-Caribbeans in England, disparities and discrimination are chronic long-term problems. For other groups, disparities and discrimination may, consistent with a long-established multi-generation immigration and crime model, especially affect second- and third-generation members of economic immigrant groups. Asian immigrants typically tend not to have high crime rates or to experience justice system disparities.
RalGDS-Dependent Cardiomyocyte Autophagy is Required for Load-Induced Ventricular Hypertrophy

Recent work has demonstrated that autophagy, a phylogenetically conserved, lysosome-mediated pathway of protein degradation, is a key participant in pathological cardiac remodeling. One common feature of cell growth and autophagy is membrane biogenesis and processing. The exocyst, an octomeric protein complex involved in vesicle trafficking, is implicated in numerous cellular processes, yet its role in cardiomyocyte plasticity is unknown. Here, we set out to explore the role of small G protein-dependent control of exocyst function and membrane trafficking in stress-induced cardiomyocyte remodeling and autophagy. First, we tested in cultured neonatal rat cardiomyocytes (NRCMs) two isoforms of Ral (RalA, RalB) whose actions are mediated by the exocyst. In these experiments, mTOR inhibition in response to starvation or Torin1 was preserved despite RalA or RalB knockdown; however, activation of autophagy was suppressed only in NRCMs depleted of RalB, implicating RalB as being required for mTOR-dependent cardiomyocyte autophagy. To define further the role of RalB in cardiomyocyte autophagy, we analyzed hearts from mice lacking RalGDS (Ralgds(-/-)), a guanine exchange factor (GEF) for the Ral family of small GTPases. RalGDS-null hearts were similar to wild-type (WT) littermates in terms of ventricular structure, contractile performance, and gene expression. However, Ralgds(-/-) hearts manifested a blunted growth response (p<0.05) to TAC-mediated pressure-overload stress. Ventricular chamber size and contractile performance were preserved in response to TAC in Ralgds(-/-) mice, and load-induced cardiomyocyte autophagy was suppressed. Interestingly, TAC-induced activation of the fetal gene program was similar in both genotypes despite the relative lack of hypertrophic growth in mutant hearts. Together, these data implicate RalGDS-mediated induction of autophagy and exocyst function as a critical feature of load-induced cardiac hypertrophy.
Posttraumatic stress following acute medical trauma in children: A proposed model of bio-psycho-social processes during the peri-trauma period

Millions of children worldwide experience acute medical events. Children’s responses to these events range from transient distress to significant posttraumatic stress disorder symptoms (PTSS). While many models suggest explanations for the development and maintenance of PTSS in adults, very few have focused on children. Current models of child PTSS are primarily restricted to the post-trauma period, thus neglecting the critical peri-trauma period when screening and preventive interventions may be most easily implemented. Research on PTSS in response to pediatric medical trauma typically examines predictors in isolation, often overlooking potentially important interactions. This paper proposes a new model utilizing the bio-psycho-social framework and focusing on peri-trauma processes of acute medical events. Understanding the relationships among bio-psycho-social factors during peri-trauma can inform early identification of at-risk children, preventive interventions and clinical care. Recommendations for future research, including the need to examine PTSS in the context of multiple influences, are discussed.
Tension-tension fatigue of copper thin films☆

Tension-tension, load-controlled fatigue results extending to over 100 000 cycles for electron-beam-evaporated copper are reported. The specimen is fabricated as a single tensile coupon with hundreds of grains across the width but only one or few through the thickness, supported on a silicon frame. These specimens had measured values of Young's modulus lower than literature values for bulk polycrystalline values, but had high values of the yield and ultimate strengths. Closed-loop feedback control of the piezoelectric actuators allowed load-controlled fatigue tests with a cycle duration of 15 s. Stress-endurance results for this set of copper films is reported and compared to previous results.
More than Men: Latino Feminist Masculinities and Intersectionality

This qualitative study analyzes the definitions of manhood provided by a US sample of 36 adult, working class Latinos who identify as feminist, and have attended institutions of higher education. Using an intersectional framework, we analyze in-depth interviews and address the research questions "To what extent did participants identify with their gender, race, ethnicity, sexuality, and class background? How did participants subjectively define what it means to be a man?". Results indicate that participants identified with their significant social groups to varying degrees. Manhood was defined in relational, ethical, and counter-hegemonic ways. Our discussion examines the way participants wove in and out of discourses related to hegemonic notions of manhood deemed as positive, while simultaneously rejecting aspects of hegemonic masculinity.
Psychotherapeutic implications of internalized homophobia in gay men.

This article describes a psychodynamic model of affirmative psychotherapy for gay men. Special note is made of the clinical issues, which arise form anti-homosexual attitudes that bias the psychological development of the homosexual male. In particular, the way in which identity formation is affected by heterosexual socialization is discussed. The psychotherapeutic implications associated with these developmental complications are indicated.
Combined paroxetine and clonazepam treatment strategies compared to paroxetine monotherapy for panic disorder

Despite the widespread application of combined selective serotonin reuptake inhibitors (SSRI) and benzodiazepine treatment for panic disorder, there has been relatively little systematic assessment of the safety and efficacy of this therapeutic strategy. Although the limited number of studies to date suggest a more rapid onset of benefit with combined treatment, this study is the first to address the critical question of whether continued combined treatment confers superior efficacy. This study is a randomized, double-blind, three-arm study in patients with panic disorder (n = 60), comparing the efficacy and safety of paroxetine and placebo (PP), paroxetine coadministered with clonazepam followed by a tapered benzodiazepine discontinuation phase (PC-D), and ongoing combination treatment (PC-M). All treatment groups demonstrated significant improvement by endpoint. There was a significant advantage for the combined treatment groups early in treatment but, subsequently, outcome in all three groups was similar. A trend towards greater achievement of endpoint remission status for the PC-D group was attenuated when variability in baseline severity was considered. The results of this study should be interpreted in the context of a relatively moderate sample size and higher rates of early dropout. Combined treatment with paroxetine and clonazepam resulted in more rapid response than with the SSRI alone, but there was no differential benefit beyond the initial few weeks of therapy. Initiating combined treatment followed by benzodiazepine taper after a few weeks may provide early benefit while avoiding the potential adverse consequences of long-term combination therapy.
The perspective wall: detail and context smoothly integrated

Tasks that involve large information spaces overwhelm workspaces that do not support efiicient use of space and time. For example, case studies indicate that information often contains linear components, which can result in 2D layouts with wide, inefficient aspect ratios. This paper describes a technique called the Perspective W’aU for visualizing linear information by smoothly integrating detailed and contextual views. It uses hardware support for 3D interactive animation to fold wide 2D layouts into intuitive 3D visualizations that have a center panel for detail and two perspective panels for context. The resulting visualization supports efficient use of space and time.
Access and Alienation: The Promise and Threat of Stewardship on Mokil Atoll

Land tenure on Mokil Atoll, an island in Pohnpei State, Federated States of Micronesia, is undergoing a notable shift from an emphasis on individual ownership of land to a system of collective, kin-based ownership. This alteration in the jural dimension of land tenure is intimately related to historical changes in the region's political economy that have entailed significant population movements and concomitant transformations in the values assigned to land, subsistence farming, local resources, and the atoll itself. This paper explores these changes by focusing on the system of stewardship that emerged as a means of protecting the ownership rights of emigrants. It examines how the system of stewardship ironically increases the threat to absentee ownership rights. This threat, coupled with economic and political forces that are compelling further emigration, and a fundamental transformation in the meaning of land, is a driving force in the transition to collective, kin-based ownership rights that secure b...
148: Association between obesity during pregnancy and the adequacy of prenatal care

Objective In the United States, more than a third of women are obese [body mass index (BMI) ≥ 30]. Although obese populations utilize health care at increased rates and have higher health care costs than non-obese patients, the adequacy of prenatal care in this population is not well established and assumed to be suboptimal. We therefore evaluated adequacy of prenatal care among obese women.
Response of nonreentrant catecholamine-mediated ventricular tachycardia to endogenous adenosine and acetylcholine. Evidence for myocardial receptor-mediated effects.

BACKGROUNDReentrant ventricular tachycardia (VT) is known to be insensitive to the nucleoside adenosine. However, we have previously identified a form of nonreentrant, catecholamine-mediated VT that can be initiated with rapid pacing, demonstrates cycle length dependence, and is sensitive to exogenous adenosine as well as to the Valsalva maneuver. The mechanism of this tachycardia is thought to be due to a catecholamine-induced, cAMP-mediated increase in intracellular calcium, resulting in delayed afterdepolarizations and triggered activity. The antiarrhythmic effects of exogenous adenosine and Valsalva on this form of VT may be due to receptor-mediated inhibition of adenylate cyclase or to noncardiac receptor-mediated effects, i.e., exogenous adenosine may modulate VT through alterations in autonomic tone by activation of arterial chemoreceptors, and Valsalva has been shown to decrease venous return, resulting in a reduction in cardiac dimensions and myocardial stretch. To clarify this issue and circumve...
Caratheodory-type selections and random fixed point theorems

Abstract We provide some new Caratheodory-type selection theorems, i.e., selections for correspondences of two variables which are continuous with respect to one variable and measurable with respect to the other. These results generalize simultaneously Michael's [21]continuous selection theorem for lower-semicontinuous correspondences as well as a Caratheodory-type selection theorem of Fryszkowski [10]. Random fixed point theorems (which generalize ordinary fixed point theorems, e.g., Browder's [6]) follow as easy corollaries of our results.
Agricultural Contracting, Competition, and Antitrust

Two powerful and related trends in the organization of U.S. farming are: production is shifting to larger family farms and agricultural contracts are increasingly being used to guide the production and marketing of farm commodities. These combined structural changes affect productivity and costs in agriculture and in the broader food sector, and also affect the financial returns to farmers, benefiting some while harming others. Structural changes have also led to initiatives, including legal challenges and legislative proposals, primarily in livestock industries, aimed at limiting the use or ameliorating some effects of contracts. Cattle feeders sued meat-
STEM writing: Applying lessons learned from a genre analysis of fermilab documents

A recent examination of four genres used at the Fermi National Accelerator Laboratory showed that genres in STEM workplaces sometimes vary significantly from ones taught in standard technical communication courses. We need to teach our STEM students how to identify genres used in their respective fields so that they can successfully complete writing assignments once they enter the workforce.
Discovery of X-Ray Quasi-periodic Oscillations from an Ultraluminous X-Ray Source in M82: Evidence against Beaming

We report the discovery with the European Photon Imaging Camera CCDs on board XMM-Newton of a 54 mHz quasi-periodic oscillation (QPO) in the greater than 2 keV X-ray flux from an ultraluminous X-ray source (ULX) in the starburst galaxy M82. This is the first detection of a QPO in the X-ray flux from an extragalactic ULX and confirms that the source is a compact object. On the basis of the QPO strength and previous Chandra observations, it appears likely that the QPO is associated with the most luminous object in the central region of M82, CXO M82 J095550.2+694047; however, XMM imaging alone is not sufficient to unambiguously confirm this. The other plausible candidate is CXO M82 J095551.1+694045; however, the QPO luminosity is comparable to the peak luminosity of this object in Chandra observations, which argues against it being the source of the QPO. The QPO had a centroid frequency of 54.3 ± 0.9 mHz, a coherence Q ≡ ν0/Δνfwhm ≈ 5, and an amplitude (rms) in the 2-10 keV band of 8.5%. Below 0.2 Hz, the power spectrum can be fitted by a power law with index ≈1 and amplitude (rms) of 13.5%. The X-ray spectrum requires a curving continuum, with a disk blackbody at T = 3.1 keV providing an acceptable fit. A broad Fe line centered at 6.55 keV is required in all fits, but the equivalent width is sensitive to the continuum model. There is no evidence of a reflection component. The implied bolometric luminosity is ≈ × 1040 ergs s-1. Archival Rossi X-Ray Timing Explorer pointings at M82 also show evidence for QPOs in the 50-100 mHz frequency range. We discuss the implications of our findings for models of ULXs.
Puzzle-solving science: the quixotic quest for units in speech perception.

Abstract Although speech signals are continuous and variable, listeners experience segmentation and linguistic structure in perception. For years, researchers have tried to identify the basic building-block of speech perception. In that time, experimental methods have evolved, constraints on stimulus materials have evolved, sources of variance have been identified, and computational models have been advanced. As a result, the slate of candidate units has increased, each with its own empirical support. In this article, we endorse Grossberg's adaptive resonance theory (ART), proposing that speech units are emergent properties of perceptual dynamics. By this view, units only “exist” when disparate features achieve resonance, a level of perceptual coherence that allows conscious encoding. We outline basic principles of ART, then summarize five experiments. Three experiments assessed the power of social influence to affect phoneme-syllable competitions. Two other experiments assessed repetition effects in monitoring data. Together the data suggest that “primary” speech units are strongly and symmetrically affected by bottom-up and top-down knowledge sources.
Short delay of delivery to allow corticosteroid adminstration in a case of preterm antepartum eclampsia

Abstract Background The current recommendation for management of antepartum eclampsia is to take steps to deliver the fetus after stabilization of the maternal condition. We delayed delivery for 60 hours in a case of antepartum preterm eclampsia to allow administration of corticosteroids for fetal lung maturity enhancement. Case A primigravida presented with eclamptic seizure at 29 weeks’ gestation without focal neurological deficits. Clinical and laboratory assessment ruled out the presence of the syndrome of hemolysis, elevated liver enzymes, low platelets; abruption; disseminated intravascular coagulation; or acute renal failure. The fetal biometry was appropriate for gestational age, and there was a normal amount of amniotic fluid. Fetal testing was reassuring. Expectancy with intravenous magnesium sulfate infusion was continued for 60 hours, allowing administration of a course of corticosteroids for enhancement of fetal lung maturity. Maternal and neonatal outcomes were satisfactory. Conclusion A 2-day delay in delivery in selected patients with preterm antepartum eclampsia allows administration of steroids for fetal lung maturity enhancement.
Multisolute extraction of organic acids by emulsion liquid membranes. I. Batch experiments and models

Abstract Emulsion liquid membranes (ELM) are water-in-oil-in-water emulsions which simultaneously extract and strip solutes from aqueous solutions. When multiple extractable solutes are present, competition for the available reagent arises, slowing extraction rates and reducing emulsion capacity for each solute. This paper compares experimental results from batch extractions with predictions from the advancing front and reversible reaction models. For mixtures of the organic acids studied ( m -cresol, phenol, and benzoic, phenylacetic, and acetic acids), reversible reaction model predictions are significantly better than those based on the advancing front approach.
Coarse-Grained Model of Collagen Molecules Using an Extended MARTINI Force Field

Collagen is the most abundant protein in the human body, providing mechanical stability, elasticity, and strength to connective tissues such as tendons, ligaments, and bone. Here, we report an extension of the MARTINI coarse-grained force field, originally developed for lipids, proteins, and carbohydrates, used to describe the structural and mechanical properties of collagen molecules. We identify MARTINI force field parameters to describe hydroxyproline amino acid residues and for the triple helical conformational structure found in collagen. We validate the extended MARTINI model through direct molecular dynamics simulations of Young’s modulus of a short 8-nm-long collagen-like molecule, resulting in a value of approximately 4 GPa, in good agreement with earlier full atomistic simulations in explicit solvent as well as experimental results. We also apply the extended MARTINI model to simulate a 300-nm-long human type I collagen molecule with the actual amino acid sequence and calculate its persistence l...
Studies of the blood chemistry of Electrophorus electricus and a new physiological saline solution based thereon

Abstract Based upon analyses of the composition of electric eel blood serum we suggest a new physiological saline solution as follows: 188 mM NaCl, 5 mM KCl, 2 mM MgCl 2 , 2 mM CaCl 2 , 0.15 mM NaH 2 PO 4 , 1.45 mM Na 2 HPO 4 and 5 mM glucose; pH 7.4. The major difference between this saline and that used in most of the previous investigations using eel electroplaques is that the total Na + concentration is increased from between 162.7 and 171.7 mequiv/l to 191 mequiv./l. This increase does not appear to affect the electrophysiological properties of the electroplaque.
Axillary lymph node metastases associated with small invasive breast carcinomas.

BACKGROUND Over the past 20 years the proportion of invasive breast carcinomas measuring ≤ 1 cm has increased progressively. Information regarding the effect of clinical and histologic characteristics on the frequency of lymph node metastases associated with small invasive breast carcinomas is limited. METHODS A review of Surveillance, Epidemiology, and End Results data was performed using cases diagnosed between January 1988 through December 1993. A total of 12,950 patients with invasive breast carcinomas measuring ≤ 1 cm undergoing a resection of the primary tumor and an axillary lymph node dissection were included in this study. The effect of clinical and histologic characteristics on the frequency of lymph node metastases was reviewed. RESULTS The frequency of lymph node metastases associated with T1a tumors was less than that observed from T1b tumors (9.6% vs. 14.3%; P < 0.001). Tumors with favorable histology (mucinous, papillary, and tubular carcinomas) had a lower frequency of lymph node metastases compared with all other histologic types (3.9% vs. 13.9%; P < 0.001). Increasing histologic grade was associated with an increased risk of lymph node metastases ranging from 7.8% in Grade 1 tumors to 21.0% in Grade 4 tumors (P < 0.001). Increasing patient age was associated with a progressively decreasing frequency of associated axillary lymph node metastases ranging from 22.6% in women age < 40 years to 10.2% in women age ≥ 70 years (P < 0.001). CONCLUSIONS Cases in which an axillary lymph node dissection can be avoided are those with an associated frequency of lymph node metastases ≤ 5%, including T1a and T1b mucinous and tubular carcinomas, T1a papillary carcinomas, and T1a Grade 1 carcinomas. Cancer 1999;85:1530–6. © 1999 American Cancer Society.
Ruptured intracranial dermoid cysts: clinical, radiographic, and surgical features.

Objective Intracranial dermoid cysts are pathologically characterized by a thick, stratified squamous epithelium cyst wall containing dermal elements. Rupture into the subarachnoid spaces and ventricles is extremely rare. We review the clinical, radiographic, and surgical features of eight ruptured dermoid cysts. Methods We retrospectively evaluated five surgically treated patients with pathologically proven ruptured dermoid cysts. Clinic notes, operative reports, and neuroimaging, including initial computed tomographic and magnetic resonance imaging scans, were reviewed. Imaging was also available on three outside patients reviewed by members of our radiology department. Results The most common presentations were headaches (57%) and seizures (42%), followed by hydrocephalus (29%) from intraventricular rupture. These lesions were consistently hypodense on computed tomographic scans and hyperintense on T1-weighted images with minimal to no enhancement after gadolinium administration. Disseminated fat droplets were present in the subarachnoid space in both cerebral hemispheres in all patients, and five patients had intraventricular rupture with fat-fluid levels in the ventricles. Gross to near-total resection of the primary lesion was achieved in all five surgically treated patients treated at our institution. Four patients had remnant tumor capsules adherent to neurovascular structures that were unresectable. Repeat resection was performed for one recurrence; there were no further recurrences during a follow-up period of 2 to 134 months (mean, 65.6 mo). Two patients with preoperative hydrocephalus eventually required ventriculoperitoneal shunting. Conclusion Ruptured intracranial dermoid cysts represent 0.18% of all central nervous system tumors surgically treated in our institution during a 12-year period. The presence of disseminated fat droplets in the subarachnoid space or ventricles on neuroimaging is diagnostic for a ruptured dermoid cyst. Gross total removal is achievable; however, residual tumor capsules adherent to neurovascular structures should be left behind to minimize complications.
The Nucleolar Localization Domain of the Catalytic Subunit of Human Telomerase

Telomerase is the enzyme essential to complete the replication of the terminal DNA of most eukaryotic chromosomes. In humans, this enzyme is composed of the telomerase reverse transcriptase (hTERT) and telomerase RNA (hTR) subunits. hTR has been found in the nucleolus, a site of assembly of ribosomes as well as other ribonucleoproteins (RNPs). We therefore tested whether the hTERT component is also found in the nucleolus, where it could complex with the hTR RNA to form a functional enzyme. We report here that hTERT does indeed localize to the nucleolus, and we mapped the domain responsible for this localization to the hTR-binding region of the protein by deletion analysis. Substitution mutations in two of the three conserved hTR-binding domains in this nucleolar localization domain (NoLD) abolished nucleolar localization. However, another mutation that impeded hTR binding did not alter this subcellular localization. Additionally, wild type hTERT was detected in the nucleolus of cells that failed to express hTR. Taken together, we propose that the nucleolar localization of hTERT involves more than just the association with the hTR subunit. Furthermore, the coincidental targeting of both the hTR and hTERT subunits to the nucleolus supports the premise that the assembly of telomerase occurs in the nucleolus.
Use of polar finite-difference approximation for solving bi-harmonic equation for plates

Abstract The bi-harmonic equation in polar coordinates is solved by using finite-difference approximations. It is found that the advantage of using a polar finite-difference grid on a plate sector with circular boundaries is that the mesh size and the location of the grid points can be chosen so that it can be superimposed on the circular boundaries. This minimizes the amount of computational work to properly apply the boundary conditions. Numerical examples of fully circular plates and plate sectors with various boundary conditions are solved. The finite-difference solutions are compared with the analytical solutions. The method is presented in general form so that it can be applied to plate sectors with any type of loading and a variety of boundary conditions. The method is found useful for several problems of this nature for which no close-form solution is available.
Subchondral magnetic resonance imaging changes in early osteoarthrosis associated with tibial osteonecrosis.

Abstract Summary: The authors report on 41 patients with acute or subacute knee pain and early or midstage degenerative arthrosis with osteonecrotic lesions in the subchondral and metaphyseal region of the medial proximal tibia. Each lesion was identified only on magnetic resonance images (MRI). These MRI changes are classified and the clinical course is defined during a follow-up period averaging 4.5 years. Radiographically, 22 patients had minimal degenerative changes; 12 had moderate arthritis; and 7 were normal. With MRI, 3 distinct types of lesions were identified. Type A lesions had localized areas of decreased signal in the subchondral area. Type B lesions had diffuse signal changes with extension into the metaphysis. Type C lesions had metaphyseal involvement as well as a marginated serpentine subchondral rim usually associated with advanced osteonecrosis. There were 9 type A lesions, 23 type B, and 9 type C. At the end of 1 year, 33 patients (80%) had no or mild symptoms, and 8 (20%) had persistent moderate pain. At 4.5-year follow-up, most patients had symptoms consistent with progressive osteoarthrosis, 12 patients had severe symptoms (29%), 17 (41%) had mild or moderate symptoms, and only 12 (29%) were asymptomatic or had minimal symptoms. The type of MRI change seen initially was predictive of prognosis. Only 6 (19%) of the 32 patients with type A or B findings had severe symptoms at last follow-up. Six (66%) of the 9 patients with a type C MRI lesion had severe symptoms or had an operation by last follow-up. Twelve patients had follow-up MRI at a mean 15 months (range, 12 to 18 months) after the initial evaluation. The type A and B changes were either absent or significantly reduced. The type C subchondral marginated rim changes remained but metaphyseal involvement was reduced. There appears to be a spectrum of tibial subchondral MRI changes associated with sudden onset of medial knee pain in patients with early osteoarthritis of the knee. These changes may be indicative of osteonecrosis. The initial MRI classification is useful in predicting prognosis. Recognition of this problem may avoid unnecessary intra-articular surgery. Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 16, No 1 (January-February), 2000: pp 76–81
Exhaust-air heat-pump performance with unsteady-state operation

Abstract The energy performance of two residential exhaust-air heat pumps (EAHP) with different condenser designs was studied experimentally in a laboratory with a focus on transient heat-pump performance associated with time varying requirements for water and space heating. Experimental variables included the total daily volume of hot water required, the schedule of hot-water demand, the temperature of water entering the hot-water tank, hot-water delivery temperature, and the temperature and flow rate of air entering the auxiliary refrigerant-heated fan coil supplied with one of the EAHP units to permit space heating. Based on the data, for a wide range of operating conditions, we derived linear correlations between the heat-pumps' time-average coefficient of performance (COP) and appropriate spatial and temporal average temperatures in the hot-water tanks. With the refrigerant-heated fan coil, the COP varied non-linearly with air flow rate. COPs ranged from 2.0 to 4.2. The control system of the EAHP with two condensers (one is the fan coil) gives priority to water heating. Based on the data, results from our previous hourly modeling of EAHP performance, data from field studies in Sweden, and new calculations, we propose a new control system that usually places priority on space heating and, thus, takes better advantage of the capacity to store heat in the water tank. We estimate that this proposed control system may increase annual energy recovery by approximately 1000 kWh if the EAHP is used in a Portland, Oregon house. Total annual energy savings due to EAHP operation in an all-electric house (compared to the same house with electric resistance space and water heating) is estimated to be approximately 6000–7000 kWh.
Elevated plasma fibrinogen rather than residual platelet reactivity after clopidogrel pre-treatment is associated with an increased ischemic risk during elective percutaneous coronary intervention.

Objectives This study was undertaken to determine the roles of serum fibrinogen and residual platelet reactivity after clopidogrel pre-treatment on ischemic events after elective percutaneous coronary intervention (PCI). Background Both elevated serum fibrinogen and high platelet reactivity with thienopyridines are associated with ischemic cardiovascular events. Elevated fibrinogen also contributes to high on-clopidogrel platelet reactivity. It is unknown whether fibrinogen and residual platelet reactivity are associated with adverse cardiovascular events through independent or interactive effects. Methods A total of 189 patients undergoing elective PCI with clopidogrel pre-treatment (75 mg daily for ≥7 days or a 600-mg bolus ≥12 h before recruitment) were prospectively enrolled. Baseline fibrinogen and platelet function using the VerifyNow P2Y12 assay (Accumetrics, San Diego, California) were obtained. Markers of ischemic myocardial injury were measured every 8 h after PCI. Results Incidence of troponin-defined periprocedural myocardial infarction (PPMI) (troponin I/T >3× upper limit of normal) was 13.9% and associated with elevated fibrinogen (363.1 ± 131.0 mg/dl vs. 309.1 ± 99.6 mg/dl; p = 0.017), higher age (68.2 ± 10.1 years vs. 63.0 ± 11.8 years; p = 0.040), and elevated platelet count. Fibrinogen level and age remained independently associated with PPMI following multiple variable and interaction testing. The incidence of creatine kinase-myocardial band (CK-MB)–defined PPMI (CK-MB >3× upper limit of normal) was 5.8% and associated with elevated fibrinogen (403.4 ± 128.0 mg/dl vs. 313.5 ± 104.6 mg/dl; p = 0.007). Platelet reactivity measurements were not associated with PPMI by either definition. Fibrinogen ≥345 mg/dl was significantly associated with both CK-MB–defined (p = 0.026) and troponin I/T–defined PPMI (p = 0.036). Fibrinogen effects were most prominent in the absence of systemic inflammation (C-reactive protein ≤0.5 mg/dl). Conclusions Elevated fibrinogen is independently associated with the risk of ischemic myocardial injury following elective PCI with clopidogrel pre-treatment regardless of platelet reactivity as measured by the VerifyNow assay.
Methodological considerations in the study of delay discounting in intertemporal choice: A comparison of tasks and modes

An experimental comparison of two commonly used delay-discounting procedures (binary choice and fill in the blank) and modes of administration (paper and pencil and computer based) was conducted. Statistically significant main effects were found for task type—steeper discounting was observed in the binary-choice task— but not for mode of administration. As simple evidence of validity, hyperbolic curves consistently provided a better fit to the data than did exponential curves for both tasks. Further, magnitude effects were also observed across conditions. Correlational results varied largely as a function of the discounting index (either k or area under the curve) under consideration. Across the two tasks, discounting indices showed modest levels of reliability [r(AUC)=.33; r(k)=.75]. The findings pointed to refinements for both the methodology and criteria that are used to study delay discounting and raised questions about the commonly assumed relationship between discounting and the construct of impulsivity.
The payment mechanisms and liquidity effects

Abstract A general equilibrium model with multiple means of payment in segmented markets is constructed to study the liquidity effects. It is shown that, under certain conditions, stored value – money issued by private entrepreneurs weakens, but does not completely eliminate the liquidity effects that exist when stored value is prohibited. The Friedman rule can be optimal in the regime with floating stored value. The impact of monetary policy now depends not only on the monetary intervention of the central bank, but also on the quantity of the outstanding private money and its velocity.
Substitution of murine for human CD4 residues identifies amino acids critical for HIV-gp120 binding

Human CD4 is the receptor for the gp120 envelope glycoprotein of human immunodeficiency virus and is essential for virus entry into the host cell1–8. Sequence analysis of CD4 has suggested an evolutionary origin from a structure with four immunoglobulin-related domains9,10. Only the two NH2-terminal domains are required to mediate gp120 binding11–13 . The extracellular segment of murine CD4 has an overall 50% identity with its human counterpart14 at the amino-acid level, but fails to bind gp12015. To define those residues of human CD4 critical for gp120 binding, we have taken advantage of this species difference and substituted all non-conserved murine for human CD4 residues between amino-acid positions 27—167. We used oligonucleotide-directed mutagenesis to create each of 16 individual mutant human CD4 molecules containing from 1—4 amino-acid substitutions. Introduction of as few as three amino acids into corresponding positions of human CD4 abrogates gp120 binding. Furthermore, these critical residues are located in domain I with a contribution from domain II. Modelling studies using the three-dimensional coordinates of the Vκ Bence-Jones REI homodimer localize the site in domain I to the C″β strand within CDR2 but projecting away from the homologues of principle antigen-binding regions CDR 1 and 3.
Advertising and recruiting

Much is said these days regarding low enrollments in computer science, reports indicate significant difficulties in recruiting women and other underrepresented groups to the field, and many studies discuss difficulties with the public image of computing. Clearly many deep societal and cultural issues underlie much of the problem, and many organizations (including ACM, ACM-W, CSTA, and SIGCSE) are considering ways to address these systemic issues.
Total thyroidectomy for benign disease in the pediatric patient--feasible and safe.

Abstract Purpose Total thyroidectomy (TT) is a safe and efficacious treatment of malignant thyroid disease in children. The role of TT in benign thyroid disease is less well-defined. The goal of this study was to compare the safety of TT performed for benign and malignant disease. Methods The medical records of 31 patients undergoing TT from January 2000 to June 2007 at a single center were reviewed. The benign cohort totaled 15 patients consisting of 12 with Graves' disease, 2 with hyperthyroidism, and 1 with large and symptomatic multinodular goiter. The malignant cohort totaled 16 patients consisting of 9 with malignant disease, 4 with a nodule and history of cancer or radiation exposure, and 3 with RET proto-oncogene mutations. Results The most common complication was transient hypocalcemia observed in 7 (46%) of 15 patients with benign disease and 9 (56%) of 16 patients with malignancy ( P = .72). Permanent hypocalcemia , defined as need for calcium supplement 6 months postprocedure, was observed in 1 patient with benign disease (6.67%) and 1 patient with malignancy (6.25%; P = 1.0). A single parathyroid gland was reimplanted in 2 patients with malignancy and 2 patients with benign disease ( P = 1.0). One case of keloid scar was noted, and no cases of recurrent laryngeal nerve palsy, nerve paralysis, tracheal injury, tracheostomy, or wound infection were encountered in either cohort. There were no cases of relapse hyperthyroidism in the benign cohort. Conclusions Similar rates of postoperative complications can be expected with TT for benign thyroid disease as compared to TT for malignant disease. Total thyroidectomy is a safe treatment option for benign thyroid disease in children.
Soft Gamma-Ray Repeaters in Nearby Galaxies: Rate, Luminosity Function, and Fraction among Short Gamma-Ray Bursts

It was suggested that some of the short-duration gamma-ray bursts (GRBs) are giant flares of soft gamma-ray repeaters (SGRs) in nearby galaxies. To test this hypothesis, I have constructed a sample of 47 short GRBs, detected by the Interplanetary Network (IPN), for which the position is constrained by at least one annulus on the celestial sphere. For each burst, I have checked whether its IPN 3 σ error region coincides with the apparent disk of one of 316 bright, star-forming galaxies found within 20 Mpc. I find a single match of GRB 000420B with M74, which could, however, be due to a chance coincidence. I estimate the IPN efficiency as a function of fluence and derive the galaxy sample completeness. I find that assuming there is a cutoff in the observed energy distribution of SGR flares at ≤10^(47) ergs, the fraction of SGRs among short GRBs with fluence above ~10^(-5) ergs cm^(-2) is <16% (95% confidence). I estimate the number of active SGRs in each one of the galaxies in the sample, and combine it with the distances to these galaxies, the IPN efficiency, and the SGR flare energy distribution, to derive the rate of giant flares with energy above 4 × 10^(46) ergs. I find that the rate of such giant flares is about (0.4-5) × 10^(-4) yr^(-1) per SGR. This rate is marginally consistent with the observed Galactic rate. Comparison of the Galactic rate with the inferred extragalactic rate implies a gradual cutoff (or steepening) of the flare energy distribution at ≾3 × 10^(46) ergs (95% confidence). Using the Galactic SGR flare rate, I set a lower limit of 1% on the fraction of SGR flares among short GRBs.