cssi/SciSciGPT-SciSciNet huggingface dataset:
Graduate medical education and physician practice location : implications for physician workforce policy

Objective. —To determine the relationship between graduate medical education and physician practice location. Design. —Cross-sectional analysis of physicians in active practice in 1993, classified by state of graduate medical education and stratified by specialty and professional activity. Logistic regression analysis was used to examine predictors of physicians remaining to practice in the same state in which they trained. Setting. —There were 82871 allopathic physicians (national random sample) and 15076 osteopathic physicians (universe) who completed graduate medical education between 1980 and 1992. Main Outcome Measure. —Practice location in the same state as graduate medical education. Results. —Overall, 51% of physicians are practicing in the state in which they obtained their graduate medical education (range among states, 6% to 71%). Generalist physicians are more likely than specialists to remain in their state of graduate medical education (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.33 to 1.40) There is a weak negative association between the number of physicians in training per capita in a state and the likelihood of a physician remaining in the state to practice (OR, 0.90; 95% CI, 0.90 to 0.91, for an increment in resident supply of 10 per 100 000 population). New York and Massachusetts, the states with the highest numbers of residents per capita, retained 51% and 49%, respectively, of their graduates, placing them near the median among states. Conclusions. —Most physician training and practice locations function as a national market, with physicians dispersing relatively widely after completing graduate medical education. States that produce high numbers of physicians per capita do not appear to play a unique role in training physicians to serve a national market. These findings pose challenges for states attempting to modify their physician supply and specialty mix. (JAMA. 1995;274:685-691)
Desorption and C–H dissociation rate constants for C2 hydrocarbons on Ni, Pd and Pt

We have employed the normalized bond index-reactive potential function (NBI-RPF) in molecular dynamics simulations of the desorption and C–H dissociation rate constants for C2 hydrocarbons on fcc(111) surfaces of Ni, Pd and Pt. The simulations yield Arrhenius preexponential factors, which together with activation barriers obtained from the unity bond index-quadratic exponential potential (UBI-QEP) method, complete the specification of the Arrhenius rate constants. Comparisons between the calculated and the available experimentally determined rate constants indicate good agreement. The calculations provide rate constants for the two different C–H bond dissociations in vinyl, while experiments were unable to distinguish between them. The values of the Arrhenius preexponentials obtained for the desorption of the C2 hydrocarbons cluster in a narrow range, which is consistent with the traditional use of a single value for the desorption preexponential for all small molecules. The C–H dissociation preexponentials span a range of three orders of magnitude. For the dissociation of a given C–H bond in the periodic metal series, a general trend is that the preexponential decreases with increasing activation barrier.
Desensitization of the dopaminergic system in bovine retina following incubation with high potassium

Abstract The effect of potassium depolarization on dopamine D 1 receptor activity in bovine retina was investigated. Preincubation of bovine retinas in buffer containing high KC1 (56 mM) as compared to a low KC1 control buffer resulted in a significant decrease in dopamine-stimulated adenylate cyclase with no change in basal or GTP-stimulated adenylate cyclase activity. The apparentV max for dopamine was decreased from102 ± 15 pmol/min/mg protein in retinas preincubated in high KC1 to 71 ± 11 pmol/min/mg protein in control retinas (n = 5). The apparentK a for dopamine stimulation of the enzyme did not change. The potassium-induced desentization could be blocked by preincubation with the dopamine antagonist cis -flupenthixol suggesting that the desentization was caused by the release of dopamine. The rapid desentization was not accompanied by a change in D 1 receptor density as assessed by binding of [ 3 H]SCH23390 nor in agonist binding as assessed by competition of the selective D 1 agonist, SKF38393, for [ 3 H]SCH23390 binding. The potassium-induced desentization was mimicked by preincubation of retinas in control medium containing isobutylmethylxanthine or dibutyryl cyclic AMP. Incubation of retinas in 56 mM KC1 also fed to a decrease in activation of adenylate cyclase by vasoactive intestinal polypeptide. These results strongly suggest that potassium depolarization leads to a very rapid heterologous desentization of adenylate cyclase in bovine retinas.
Thermoelectric properties of P-type Yb-filled skutterudite YbxFeyCo4-ySb12

While intensive work has been done on n-type Yb filled skutterudites in the past, very little is known about their p-type counterparts for potential applications as thermoelectric materials. In this paper, we report a systematic study of high temperature thermoelectric transport properties of p-type Yb-filled Fe-compensated skutterudites YbxFeyCo4-ySb12 with the aim to complement the knowledge base for the Yb-filled skutterudite family. The highest ZTmax ¼ 0.6 was found in Yb0.6Fe2Co2Sb12 at 782 K. YbFe4Sb12 exhibits the second highest ZTmax ¼ 0.57 at 780 K, which is much higher than the previous estimate of 0.4 for the same composition.
Association of Type Traits with Reasons for Disposal

Abstract Reasons for disposal of 3,475 cows from 188 New York Holstein herds were compared with type appraisal and milk yield in first lactation to study the relationship between type traits measured early in life and later reasons for disposal. Reasons for disposal were grouped as production (32%), udder (22%), reproduction (27%), inabilities or disease (8%), workability (3%), type (3%), and other (5%). Few traits measured before 49 months of age had any significant value in predicting the reason for a cow's eventual disposal. These results in addition to earlier studies of heritability suggest that type traits measured in the first lactation have only a limited value in selection for longevity.
Reactions of propylene oxide with 2′-deoxynucleosides and in vitro with calf thymus DNA

Abstract Propylene oxide (PO) is a direct-acting mutagen and rodent carcinogen. We have studied how PO modifies 2′-deoxynucleosides at pH 7.0–7.5 and 37°C for 10 h. PO reacts as an S N 2 alkylating agent by forming the following 2-hydroxypropyl (HP) adducts: N 6 -HP-dAdo (7% yield), 7-HP-Gua (37%) and 3-HP-dThd (4%). Alkylation at N-3 of dCyd resulted in conversion of the adjacent exocyclic imino group at C-4 to an oxygen (hydrolytic deamination) with the formation of a dUrd adduct, 3-HP-dUrd (14%). Ultraviolet spectroscopy and mass spectrometry were used for the structural determination of these adducts. Confirmation of the unexpected 3-HP-dUrd adduct was provided by an accurate mass measurement technique where diagnostic ions in the mass spectra of 3-HP-dUrd were measured to within 0.0005 atomic mass units of the predicted mass. PO was reacted in vitro with calf thymus DNA (pH 7.0–7.5, 37°C, 10 h) and yielded N 6 -HP-dAdo (1 nmol/mg DNA), 3-HP-Ade (14 nmol/mg DNA), 7-HP-Gua (133 nmol/mg DNA) and 3-HP-dUrd (13 nmol/mg DNA). A mechanism for the hydrolytic deamination of 3-HP-dCyd to 3-HP-dUrd involving the OH on the HP side chain is proposed. This cytosine to uracil conversion may play a role in the mutagenic and carcinogenic activity of this epoxide.
The role of migration in central nervous system neuronal development

The past year has seen the emergence of significant new information on the control of neurogenesis and migration, and the establishment of neuronal identity in three systems: developing cerebellum, cortex, and optic tectum. These findings have important implications for the role of glial-guided migrations in central nervous system neuronal development.
The Application of Neutron Transport Green’s Functions to Threat Scenario Simulation

Radiation detectors provide deterrence and defense against nuclear smuggling attempts by scanning vehicles, ships, and pedestrians for radioactive material. Understanding detector performance is crucial to developing novel technologies, architectures, and alarm algorithms. Detection can be modeled through radiation transport simulations; however, modeling a spanning set of threat scenarios over the full transport phase-space is computationally challenging. Previous research has demonstrated Green’s functions can simulate photon detector signals by decomposing the scenario space into independently simulated submodels. This paper presents decomposition methods for neutron and time-dependent transport. As a result, neutron detector signals produced from full forward transport simulations can be efficiently reconstructed by sequential application of submodel response functions.
Robust stability in power systems with nonlinear loads using generalized Kharitonov's theorem

In this paper a linear model is systematically derived for an n bus m machine system with nonlinear voltage dependent loads at the network buses. The model is versatile and can be used to study different phenomena such as steady-state stability, voltage stability etc. In addition to obtaining the system A matrix, we also obtain a transfer function between load voltages/angles and real/reactive powers at the network buses which is used for robust stability analysis using generalized Kharitonov's theorem. For a given operating point and a given load model, the system A matrix and the eigenvalues can be obtained easily. Eigenvalues for different load models are investigated.
Ocular and Systemic Manifestations of Encephalocraniocutaneous Lipomatosis

Encephalocraniocutaneous lipomatosis is a congenital neurocutaneous syndrome with epibulbar choristomas and connective tissue nevi of the eyelids as common ophthalmic manifestations. Systemic manifestations occur ipsilateral to the ocular lesions and include lipomas of the cranium and central nervous system, alopecia of the scalp, and abnormalities of the central nervous system. We treated a child with encephalocraniocutaneous lipomatosis who required removal of an epibulbar choristoma. Pathologic evaluation of the epibulbar choristoma in our patient showed the presence of ectopic lacrimal gland tissue and cartilage. Encephalocraniocutaneous lipomatosis should be considered, together with Goldenhar's syndrome and sebaceous nevus syndrome, in the differential diagnosis of conditions associated with epibulbar choristomas.
Magnetic targeting of aggregated nanoparticles for advanced lung therapies: A robotics approach

This paper studies the use of the innovative concept of MRI-targeted drug delivery platform for robotic targeting of magnetized aerosol in the lungs. The goal is to increase dramatically the therapeutic effectiveness by increasing the aerosol drug concentration in the lesion while reducing its presence in healthy lung tissues. For this purpose, a parametric analysis is conducted to specify the magnetic forces required to efficiently target magnetized liposomal agents to the lungs. The force capabilities of the MRI system are assessed and their limitations with respect to magnetic targeting are identified. To overcome these limitations, the paper proposes a novel approach: to scale-up the MRI magnetic forces by using the MRI magnetic field to generate agglomerations of the aerosolized liposomal agents (or agglomerations of aerosol droplets). The formation of agglomerations increases the magnetic volume and thus increases the magnetic forces. Furthermore the paper presents a dynamic simulation platform, developed by the authors, to assess the feasibility of the concept and to investigate ways to control the size geometry and break-up rate of the agglomerations. The dynamic models of this computational tool are described in detail. The simulation results predict aggregation patterns, whose size and orientation can be controlled by external magnetic fields.
Edmond Halley and Early Geophysics

Summary Edmond Halley, primarily an astronomer, was also a pioneer in some aspects of geophysics. In particular he carried out original work on geomagnetism, on the aurora, the behaviour and cause of the trade winds, and made some scientific attempts to determine the age of the Earth. A brief sketch is given of his work, which opened a new chapter in the study of the Earth as a physical body.
Co-assembly of Kv4 α Subunits with K+ Channel-interacting Protein 2 Stabilizes Protein Expression and Promotes Surface Retention of Channel Complexes

Members of the K+ channel-interacting protein (KChIP) family bind the distal N termini of members of the Shal subfamily of voltage-gated K+ channel (Kv4) pore-forming (α) subunits to generate rapidly activating, rapidly inactivating neuronal A-type (IA) and cardiac transient outward (Ito) currents. In heterologous cells, KChIP co-expression increases cell surface expression of Kv4 α subunits and Kv4 current densities, findings interpreted to suggest that Kv4·KChIP complex formation enhances forward trafficking of channels (from the endoplasmic reticulum or the Golgi complex) to the surface membrane. The results of experiments here, however, demonstrate that KChIP2 increases cell surface Kv4.2 protein expression (∼40-fold) by an order of magnitude more than the increase in total protein (∼2-fold) or in current densities (∼3-fold), suggesting that mechanisms at the cell surface regulate the functional expression of Kv4.2 channels. Additional experiments demonstrated that KChIP2 decreases the turnover rate of cell surface Kv4.2 protein by inhibiting endocytosis and/or promoting recycling. Unexpectedly, the experiments here also revealed that Kv4.2·KChIP2 complex formation stabilizes not only (total and cell surface) Kv4.2 but also KChIP2 protein expression. This reciprocal protein stabilization and Kv4·KChIP2 complex formation are lost with deletion of the distal (10 amino acids) Kv4.2 N terminus. Taken together, these observations demonstrate that KChIP2 differentially regulates total and cell surface Kv4.2 protein expression and Kv4 current densities.
HMO market penetration and costs of employer-sponsored health plans

Using two employer surveys, we evaluate the role of increased health maintenance organization (HMO) market share in containing costs of employer-sponsored coverage. Total costs for employer health plans are about 10 percent lower in markets in which HMOs' market share is above 45 percent than they are in markets with HMO enrollments of below 25 percent. This is the result of lower premiums for HMOs than for non-HMO plans, as well as the competitive effect of HMOs that leads to lower non-HMO premiums for employers that continue to offer these benefits. Slower growth in premiums in areas with high HMO enrollments suggests that expanded HMO market share may also lower the long-run growth in costs.
Some statistical applications of Faa di Bruno

The formula of Faa di Bruno is used to calculate higher order derivatives of a composition of functions. In this paper, we first review the multivariate version due to Constantine and Savits [A multivariate Faa di Bruno formula with applications, Trans. AMS 348 (1996) 503-520]. We next derive some useful recursion formulas. These results are then applied to obtain both explicit expressions and recursive formulas for the multivariate Hermite polynomials and moments associated with a multivariate normal distribution. Finally, an explicit expression is derived for the formal Edgeworth series expansion of the distribution of a normalized sum of iid random variables.
Locally Produced Anti-Phosphorylcholine and Anti-Oxidized Low-Density Lipoprotein Antibodies in Gingival Crevicular Fluid from Aggressive Periodontitis Patients

Background: Sera from patients with periodontal attachment loss contain higher concentrations of IgG anti-phosphorylcholine (anti-PC) than sera from healthy subjects. Furthermore, a large proportion of plaque bacteria bear PC-containing surface antigens, implicating the oral flora as a source of immunogen for anti-PC. Additionally, anti-PC is cross-reactive with a variety of oral bacterial antigens and human antigens such as oxidized low-density lipoprotein (oxLDL). We hypothesized that, if the oral flora is a source of PC antigens, then we should be able to detect local anti- PC and anti-oxLDL production in gingival crevicular fluid (GCF). Methods: To test this, we collected 66 GCF samples from 15 patients with aggressive periodontitis and examined both the GCF samples and serum samples for their content of IgG anti-PC, IgG anti-LDL, and IgG anti-oxLDL by enzyme-linked immunosorbent assay. We also determined levels of anti-tetanus toxoid (anti-TT) as a non-oral antigen control. Serum and GCF concentratio...
Distribution of Biological Control Agents of Leafy Spurge (Euphorbia esulaL.) in the United States: 1988–1996

Abstract Leafy spurge,Euphorbia esula(Euphorbiaceae), is a perennial plant native to Eurasia that has become a widespread weed in North America. Since 1988, the United States Department of Agriculture, Plant Protection and Quarantine, Animal and Plant Health Inspection Service (USDA-APHIS-PPQ) has coordinated a classical biological control implementation program against leafy spurge in the United States. Through this program, nine Eurasian insect species have been imported and released in the United States, including six species of flea beetles,Aphthonaspp. (Coleoptera: Chrysomelidae), a root-boring moth,Chamaesphecia hungarica(Lepidoptera: Sesiidae), a root-boring beetle,Oberea erythrocephala(Coleoptera: Cerambycidae), and a gall midge,Spurgia esulae(Diptera: Cecidomyiidae). These species have been released in 188 counties in 19 states. Established populations of at least one agent are present in 148 counties in 18 states, while populations of at least one agent in 62 counties in 16 states are large enough to permit collection and distribution to other leafy spurge-infested areas. Biological control agents have been released throughout areas of the United States infested by leafy spurge, and the initial phase of the USDA-APHIS-PPQ implementation program is nearly complete.
Thromboembolic complications after neuroform stent-assisted treatment of cerebral aneurysms: The Duke cerebrovascular center experience in 235 patients with 274 stents

Background The Neuroform Stent has facilitated the endovascular treatment of wide-necked cerebral aneurysms. It is unknown which factors pose risks of thromboembolic events after stent placement. Objective This series is the largest single-center study reporting on the incidence of and factors influencing thromboembolic complications after Neuroform stent placement. Methods A total of 235 patients were treated with 274 Neuroform stents. The thromboembolic event rate was determined by imaging or clinical evidence of cerebrovascular accident within 90 days of stent placement; for patients with incomplete follow-up through chart review, telephone interviews were conducted. Analyses were performed to investigate patient factors that may be associated with stroke. Results Most aneurysms were unruptured; 30 patients (12.8%) presented with acute subarachnoid hemorrhage. Twelve patients of the 224 with follow-up (5.4%, 95% confidence interval: 2.4%-8.3%) demonstrated imaging or clinical evidence of a new thromboembolic event within 90 days of stent placement. There was a 3.1% thromboembolic rate for unruptured aneurysms and a 20% rate in patients with subarachnoid bleed. Hemorrhage was significantly associated with having a thromboembolic event (P = .002). There was a trend toward an increased thromboembolic event rate for patients with hypertension (P = .07). Larger stent caliber was significantly associated with a decreased thromboembolic event rate (P = .032). Conclusion Our results suggest that the thromboembolic event rate associated with Neuroform stent use is low in unruptured aneurysms. In ruptured aneurysms, the complication rate is high, possibly partly related to restricted use of antiplatelet therapy. Stent size and hypertension may be associated with the risk of stroke, but additional studies are needed to confirm their significance.
Infection of HLA-DR1 Transgenic Mice with a Human Isolate of Influenza A Virus (H1N1) Primes a Diverse CD4 T-Cell Repertoire That Includes CD4 T Cells with Heterosubtypic Cross-Reactivity to Avian (H5N1) Influenza Virus

The specificity of the CD4 T-cell immune response to influenza virus is influenced by the genetic complexity of the virus and periodic encounters with variant subtypes and strains. In order to understand what controls CD4 T-cell reactivity to influenza virus proteins and how the influenza virus-specific memory compartment is shaped over time, it is first necessary to understand the diversity of the primary CD4 T-cell response. In the study reported here, we have used an unbiased approach to evaluate the peptide specificity of CD4 T cells elicited after live influenza virus infection. We have focused on four viral proteins that have distinct intracellular distributions in infected cells, hemagglutinin (HA), neuraminidase (NA), nucleoprotein, and the NS1 protein, which is expressed in infected cells but excluded from virion particles. Our studies revealed an extensive diversity of influenza virus-specific CD4 T cells that includes T cells for each viral protein and for the unexpected immunogenicity of the NS1 protein. Due to the recent concern about pandemic avian influenza virus and because CD4 T cells specific for HA and NA may be particularly useful for promoting the production of neutralizing antibody to influenza virus, we have also evaluated the ability of HA- and NA-specific CD4 T cells elicited by a circulating H1N1 strain to cross-react with related sequences found in an avian H5N1 virus and find substantial cross-reactivity, suggesting that seasonal vaccines may help promote protection against avian influenza virus.
The Artificial Earthquake Electric Restructuring in California

The electric power system is a crucial aspect of the infrastructure of contemporary society. The electric power system has undergone an artificial earthquake. Vertical integration was broken up, generation made competitive, and utilities pushed out of generation. Did this artificial quake, which is of worldwide interest, have to happen or are there lessons to learn? From the viewpoint of delivering physical reliability of services to customers, the system clearly was not “broke.” Interest groups’politics seem to have been the driver, the main groups being industrial customers, independent power producers, and “Chicago School” economists. The changes have not producedthe expectedreduction of rates to customers, have resultedin major financial consequences for utilities, ledthe state into the power-purchasing business, andcalledinto question aspects of the state’s own finances. In policy making, the pure theory of any discipline is likely to yieldunexpectedandundesirable results.
Gabapentin’s effects on hot flashes and hypothermia

Article abstract The author describes six cases in which gabapentin treatment reduced the frequency of hot flashes. In addition, gabapentin treatment enhanced the frequency of hypothermic episodes in a separate patient with known hypothalamic dysfunction. Gabapentin may act directly upon temperature regulatory centers.
Factors controlling embryonic heart cell proliferation in serum-free synthetic media

Embryonic chick cardiac cell cultures, plated on collagen-coated dishes, containing serum-free synthetic media proliferate actively. The basic medium contained Ham's F12 nutrient mixture, fetuin, ascorbic acid, and bovine serum albumin. This medium was supplemented with various combinations of factors: endothelial cell growth supplement (ECGS), epidermal growth factor (EGF), insulin (I), transferrin (T), selenium (S), hydrocortisone, and thyroxine or supplemented alone. Basic medium supplemented with ECGS alone contributes to the highest final cell density among all other factors used in various combinations or alone. The final cell density of the control culture with 2% fetal bovine serum was higher than those of all experimental cultures and an additional control culture grown in the basic medium. Combinations of factors without ECGS do not promote significant cell proliferation. Thyroxine is required to induce optimal differentiation and contractility of cardiac myocytes in vitro. Fibronectin and laminin did not show any more influence than collagen did on the growth and maintenance of cardiac myocytes in serum-free media. The proportion of cardiac muscle cells in ECGS-containing media was higher than those in other experimental media and control media with the exception of ECGS and ITS-containing medium that showed lower proportion of cardiac myocytes than that of serum-containing medium on Days 3 and 5. The profiles of incorporation of [3H]thymidine into DNA of heart cells in experimental and control cultures showed a peak in incorporation values within the first week of culture and subsequently declined. Autoradiography studies revealed that cardiac myocytes in culture supplemented with ECGS alone attained a peak in labeling index on Day 1 with approximately 62% labeled cells. Subsequently, the labeling indices declined. Cardiac myocytes grown in media without ECGS showed significantly lower labeling indices than those in ECGS-containing media. This study has demonstrated the influence of ECGS, EGF and ITS in promoting the growth of cardiac myocytes and also in contributing to the maintenance of contractile cardiac myocytes in serum-free, long-term culture. The influence of ECGS on heart cell proliferation is considered to be superior to that of EGF and ITS.
Non‐resident enrollment and non‐resident tuition at land grant colleges and universities

Universities around the United States are seeking ways to attract students to their institutions. One possible strategy is to compete for out‐of‐state students. Since an early 1970s examination of the determinants of student migration by Tuckman, there have been several subsequent studies that have either further developed the methodology of the studies or taken some different perspective on the problem. This paper differs from the existing literature in two ways. First, it focuses exclusively on land‐grant institutions. Second, it uses panel data rather than just time‐series or cross‐sectional data. Evidence regarding the impact of historical Black college/university status and regional variations are presented as well. The evidence indicates that quality has more influence on student migration than price, indicates that historical Black college/universities attract fewer out‐of‐state students than other land grant institutions and indicates that there are non‐specific regional differences in land grant ...
Toxicological Significance of Enzyme Activities in Profenofos-Resistant Tobacco Budworms,Heliothis virescens(F.)

Abstract Resistance to profenofos and activities of enzymes associated with metabolism of organophosphorus insecticides were measured in larvae of the tobacco budworm, Heliothis virescens (F.), that were field-collected from Louisiana during the 1995 cotton growing season. High frequencies of profenofos resistance were recorded in all field-collected strains and were strongly correlated with esterase activity and moderately correlated with glutathione S -transferase activity toward 1-chloro-2,4-dinitrobenzene. Mean levels of acetylcholinesterase sensitivity to inhibition by chlorpyrifos oxon were lower in some field strains than that of an insecticide-susceptible strain; however, acetylcholinesterase sensitivity and resistance were poorly correlated in all field strains. Finally, there was no correlation between resistance and activities of P450-monooxygenase toward p -nitroanisole or glutathione S -transferase toward 1,2-dichloro-4-nitrobenzene. These results suggest possible contributions of both metabolic and target site mechanisms toward profenofos resistance in this insect.
Reachability analysis in probabilistic biological networks

Extra-cellular molecules trigger a response inside the cell by initiating a signal at special membrane receptors (i.e.,sources), which is then transmitted to reporters (i.e., targets) through various chains of interactions among proteins. Understanding whether such a signal can reach from membrane receptors to reporters is essential in studying the cell response to extra-cellular events. This problem is drastically complicated due to the unreliability of the interaction data. In this paper, we develop a novel method, called PReach ( P robabilistic Reach ability), that precisely computes the probability that a signal can reach from a given collection of receptors to a given collection of reporters when the underlying signaling network is uncertain. This is a very difficult computational problem with no known polynomial-time solution. PReach represents each uncertain interaction as a bi-variate polynomial.It transforms the reachability problem to a polynomial multiplication problem. We introduce novel polynomial collapsing operators that associate polynomial terms with possible paths between sources and targets as well as the cuts that separate sources from targets. These operators significantly shrink the number of polynomial terms and thus the running time. PReach has much better timecomplexity than the recent solutions for this problem. Our experimental results on real data sets demonstrate that this improvement leads to orders of magnitude of reduction in the running time over the most recent methods. Availability: All the data sets used, the software implemented and the alignments found in this paper are available at http://bioinformatics.cise.ufl.edu/PReach/.
Crystal structure mediates mode of cell death in TiO2 nanotoxicity

Certain properties that nanoparticles possess differentiate them from their bulk counterparts, and these characteristics must be evaluated prior to nanoparticle studies and include: size, shape, dispersion, physical and chemical properties, surface area, and surface chemistry. Early nanotoxicity studies evaluating TiO2 have yielded conflicting data which identify either size or crystal structure as the mediating property for nano-TiO2 toxicity. However, it is important to note that none of these studies examined size with the crystal structure composition controlled for or examined crystal structure while controlling the nanoparticle size. The goal of this study was to evaluate the role of size and crystal structure in TiO2 nanotoxicity while controlling for as many other nanoproperties as possible using the HEL-30 mouse keratinocyte cell line as a model for dermal exposure. In the size-dependent studies, all the nanoparticles are 100% anatase, and aggregate sizes were determined in order to take into account the effect of agglomeration on size-dependent toxicity. In addition, varying crystal structures were assessed while the size of the nanoparticles was controlled. We were able to identify that both size and crystal structure contribute to cytotoxicity and that the mechanism of cell death varies based on crystal structure. The 100% anatase TiO2 nanoparticles, regardless of size, induced cell necrosis, while the rutile TiO2 nanoparticles initiated apoptosis through formation of reactive oxygen species (ROS).
Effect hypokinesia on the ultrastructure of rat neocortex

The effect of 40, 90, and 120-day hypokinesia and nonstressful hypokinesia on the ultrastructure of cingular convolution, motor and frontal-parietal areas of rat cortex were investigated. Differences were found only in the ultrastructure of cingular convolution after hypokinesic stress. In each area both procedures led to a decrease in the number and variety of spike and axospike synapses.
Modeling donor/acceptor interactions: Combined roles of theory and computation

An extended superexchange model for electron transfer (ET) matrix elements (H{sub DA}) has been formulated as a superposition of McConnell-type pathways and implemented by combined use of configuration interaction wave functions (obtained using the INDO/s model of Zerner and co-workers) and the generalized Muliken-Hush formulation of charge-localized diabatic states. Applications are made for et (and hold transfer) in several donor/bridge/acceptor radical anion (and cation) systems, (DBA){sup {+-}}, allowing detailed comparison with experimental H{sub DA} estimates. For the case of oligo phenylene ethynylene (OPE) bridges, the role of {pi} and {sigma} electronic manifolds for different distributions of phenylene torsion angles is analyzed in detail.
Content for one: developing a personal content management system

You may have browsed or searched one of the large Content Management Systems that store and display useful information; many universities, departments, and library research desks have turned to these to manage both their long-term reference materials and daily-changing data. What if we'd like to manage our own content, but our staff consists of one overworked, time-challenged, long-term-memory-impaired worker: ourself?My own information storage system was "heap-based:" several overflowing desktops of stacks of papers, journals, post-its, and scribbled memos. I needed something better, but didn't have anyone to give this project to and only a modest amount of time to devote to a new project myself.I decided to look at a range of open-source Content Management Systems (CMS) and compare freely-available packaged systems with a completely handmade system based on PHP and MySQL -- all topics with which I had little or no experience.Advantages to setting up a CMS like this (beyond organizing your own data) include gaining familiarity with concepts and systems that are likely to be increasingly important in the future. You may, if you wish, become a mentor to others with the same needs. The goal is to allow the wide-spread sharing of ideas and content without having to spend a lot of time fooling around with the technical details of presentation - a useful tool many people might be interested in.I hope my experience and conclusions will help you decide if a CMS is the answer to your data problems, and which path might be the best route for you to take.
Past and future in microtubule research

Microtubules. Edited By K. Roberts and J. Hyams. Pp.595. (Academic: London and New York, 1979.) £34, $78.50.
Regulation of the MDM2-p53 Pathway by Ribosomal Protein L11 Involves a Post-ubiquitination Mechanism

Inhibition of the MDM2-p53 feedback loop is critical for p53 activation in response to cellular stresses. The ribosomal proteins L5, L11, and L23 can block this loop by inhibiting MDM2-mediated p53 ubiquitination and degradation in response to ribosomal stress. Here, we show that L11, but not L5 and L23, leads to a drastic accumulation of ubiquitinated and native MDM2. This effect is dependent on the ubiquitin ligase activity of MDM2, but not p53, and requires the central MDM2 binding domain (residues 51-108) of L11. We further show that L11 inhibited 26 S proteasome-mediated degradation of ubiquitinated MDM2 in vitro and consistently prolonged the half-life of MDM2 in cells. These results suggest that L11, unlike L5 and L23, differentially regulates the levels of ubiquitinated p53 and MDM2 and inhibits the turnover and activity of MDM2 through a post-ubiquitination mechanism.
Determination of solid-state fungal growth by Fourier transform infrared-photoacoustic spectroscopy

Photoacoustic spectroscopy (PAS) does not require optically transparent samples and is, therefore, well suited for analysis of solid-state samples. Fourier transform infrared (FTIR)-PAS of solid materials containing protein exhibited strong absorption in the amide I and amide II regions of the IR spectrum. Growth of a filamentous fungus, Phanerochaete chrysosporium, on cellulose discs was quantitatively determined by monitoring amide I absorption with FTIR-PAS.
Are there constraints on learned responses to odors from rewarded and nonrewarded rats

This study determined if test rats could utilize biological odors, generated from donor rats receiving reward (R) and frustrative nonreward (N) treatments, to predict reward and nonreward goal events equally well. In Phase 1, two groups of test rats were exposed to R and N odors that signaled, respectively, either R and N goal events (“same” condition) or N and R goal events (“opposite” condition). Rats demonstrated significant discriminative use of these odors under both conditions. Subjects in the “opposite” condition, however, were slightly slower to learn the discrimination. Reversal learning was readily accomplished in Phase 2, regardless of the same-opposite factor. Thus, little evidence for a constraint on learning was found, and an interpretation in terms of interfering response tendencies and their habituation seemed favored.
Selective inhibition by secosteroids of 5α-reductase activity in human sex skin fibroblasts

Abstract The effects of 5,10-secoestra-4,5-diene-3,10,17-trione (Compound I) and 5,10-seco-19-norpregna-4,5-diene,3,10,20-trione (Compound II) on the 5α-reductase activity and on the androgen receptors of normal human sex skin fibroblasts were investigated. The V max and K m , of the transformation of testosterone to 5α-reduced products was 387 pg/μg DNA/30 min and 234 × 10 − 9M, respectively. When the inhibitors were introduced in the assay, the 5α-reductase activity was markedly reduced, Compound I being a less potent inhibitor than Compound II. At 15 min, the inhibition was greater than at 30 and 60 min. The K 1 for Compound I was 160 × 10 − 6M with a V max of 83 to 553 pg/Pg DNA/30 min. For Compound II, the Ki was 0.53 × 10 −6 M with a V max of 70 to 340 pg/yg DNA/30 min. The inhibition was of the noncompetitive type. Studies with androgen receptors showed that Compound I had a lower affinity for the receptors than Compound II. The ID 50 for a 3 H-DHT and 3 H-T for Compound I were 42.9 × 10 −7 M and 8.6 × 10 − 7M, respectively, whereas for Compound II, they were 10.6 × 10 −7 M and 4.8 × 10 −7 M.
Layers of identity: Multiple psychological senses of community within a community setting

This article explores psychological sense of community (PSOC), a feeling of belonging to, importance of, and identification with a community. In much of the research on PSOC, there has been a focus on identifying a single PSOC for an individual in a setting. Qualitative and quantitative data are used here to investigate the presence and operation of multiple psychological senses of community for individuals. These multiple PSOCs are explored in two macro, territorial settings and a subcommunity of one of these settings: a job training and education center for underserved women in Baltimore City. Exploration of multiple PSOCs at the macro- and subcommunity levels expands our conceptualization of the operation of PSOC and has real-life implications for fostering positive outcomes in multicultural communities. © 2001 John Wiley & Sons, Inc.
A Frobenius formula for the characters of the Hecke algebras

This paper uses the theory of quantum groups and the quantum Yang-Baxter equation as a guide in order to produce a method of computing the irreducible characters of the Hecke algebra. This approach is motivated by an observation of M. Jimbo giving a representation of the Hecke algebra on tensor space which generates the full centralizer of a tensor power of the “standard” representation of the quantum group\(U_q (\mathfrak{s}l(n))\). By rewriting the solutions of the quantum Yang-Baxter equation for\(U_q (\mathfrak{s}l(n))\) in a different form one can avoid the quantum group completely and produce a “Frobenius” formula for the characters of the Hecke algebra by elementary methods. Using this formula we derive a combinatorial rule for computing the irreducible characters of the Hecke algebra. This combinatorial rule is aq-extension of the Murnaghan-Nakayama for computing the irreducible characters of the symmetric group. Along the way one finds connections, apparently unexplored, between the irreducible characters of the Hecke algebra and Hall-Littlewood symmetric functions and Kronecker products of symmetric groups.
Linear mitochondrial plasmids of F. oxysporum are novel, telomere-like retroelements.

Abstract Diverse types of linear RNA and DNA autonomously replicating genetic elements exist in prokaryotic and eukaryotic hosts, yet linear elements that replicate by reverse transcription have not been identified. Here, we report the sequence and organization of two linear mitochondrial plasmids of the fungal plant pathogen F. oxysporum and the characterization of a plasmid-associated reverse transcriptase activity. Plasmids pFOXC2 and pFOXC3 are 1.9 kb in length and have a "clothespin" genomic structure, which includes a terminal hairpin and a telomere-like iteration of a 5 bp sequence at the other terminus. The retroplasmid replication cycle involves novel strategies for copying terminal sequences, which may provide clues concerning the origin of telomerase as well as the evolution of linear DNAs.
Reconstruction of historical abundance and recruitment of red king crab during 1960-2004 around Kodiak, Alaska

Abstract Gulf of Alaska waters around Kodiak Island once supported the world's largest fishery for red king crab, Paralithodes camtschaticus. Fishery harvests occurred at low levels beginning in the 1930s, but increased rapidly in the 1960s to a peak harvest of 42,800 mt in 1965. However, stock abundance declined dramatically in the late 1960s, and again in the early 1980s. The history of the fishery included a variety of management measures, such as time and area closures and changes to minimum size limits. Despite these efforts, the stock was ultimately recognized as depleted, and a commercial fishery closure since 1983 has not resulted in a stock recovery. We developed a quantitative retrospective analysis to understand the conditions surrounding the rise, collapse, and continued depleted status of the red king crab stock around Kodiak Island, Alaska. Our approach used a population dynamics model to estimate abundance, recruitment, and fishing and natural mortality over time. The model included three male and four female “stages” and incorporated catch composition data from the fishery (1960–1982), a pot survey (1972–1986), and a trawl survey (1986–2004). Male abundance is estimated for 1960 to 2004, but the available data limit analysis of females to the years 1972 to 2004. During a critical time of fishery development in the late 1960s, a chance period of strong recruitment helped promote the capitalization of this fishery. Very high harvest rates in the late 1960s were not sustainable, likely due to reproductive failure associated with sex ratios skewed toward females following a recruit-driven fishing period in the 1970s. Environmental and ecological changes, associated with a climate regime shift, likely exacerbated these problems.
Analysis of substrate recognition by the ribonucleoprotein endonuclease RNase P.

Ribonuclease P (RNase P), is a ribonucleoprotein complex that catalyzes the site-specific cleavage of pre-tRNA and a wide variety of other substrates. Although RNase P RNA is the catalytic subunit of the holoenzyme, the protein subunit plays a critical role in substrate binding. Thus, RNase P is an excellent model system for studying ribonucleoprotein function. In this review we describe methods applied to the in vitro study of substrate recognition by bacterial RNase P, covering general considerations of reaction conditions, quantitative measurement of substrate binding equilibria, enzymatic and chemical protection, cross-linking, modification interference, and analysis of site-specific substitutions. We describe application of these methods to substrate binding by RNase P RNA alone and experimental considerations for examining the holoenzyme. The combined use of these approaches has shown that the RNA and protein subunits cooperate to bind different portions of the substrate structure, with the RNA subunit predominantly interacting with the mature domain of tRNA and the protein interacting with the 5′ leader sequence. However, important questions concerning the interface between the two subunits and the coordination of RNA and protein subunits in binding and catalysis remain.
Power Control in Full Duplex Underlay Cognitive Radio Networks: A Control Theoretic Approach

Both cognitive radio (CR) and full duplex transmissions are both effective means to enhance spectrum efficiency and network capacity. In this paper, we investigate the problem of power control in an underlay CR network where the CR nodes are capable of full-duplex (FD) transmissions. The objective is to guarantee the required quality of service (QoS) in the form of a minimum signal-to-interference-plus-noise (SINR) ratio at each CR user and keep the interference to primary users below a prescribed threshold. We design an effective distributed power control scheme that integrates a proportional-integral-derivative (PID) controller and a power constraint mechanism to achieve the above goals. WE then develop a hybrid scheme that can switch between FD and half duplex modes. The proposed schemes are validated with extensive simulations.
Taxane diterpenes 4: Autoxidation, epimerization and isomerization for the introduction of functionality into the taxane ABC ring system

Abstract The bicyclo[5.4.0]undecenone 4 was converted through a four step sequence involving activation, gem-methylcyclopropanation and reductive cleavage into 18 α β , containing the B/C rings of the taxanes. The A-ring has been attached to the B/C ring system by cyclization of the sulfone-ester 23α to give 24. The A-ring was modified to give 29, which underwent β-elimination of the 3,10-oxido bridge via a dianion, followed by transannular hydride shift to give the butenolide 30 and 32. Autoxidation of 30 gave 33 which was further elaborated into the trans-fused B C adduct 35. The isomeric 3,10-diones trans-39 and cis-45 undergo autoxidation using t-BuOK/THF/O2/P(OEt)3 to give 2 and 46 respectively without B C cis/trans isomerization.
Isolation and characterization of low-pH fluoride-resistant mutants of Streptococcus mutans.

Stable fluoride-resistant mutants of Streptococcus mutans GS-5 were isolated at pH 6.0 and pH 5.0. Fluoride-resistant mutants isolated at pH 5.0 demonstrated greater resistance to sodium fluoride at pH 7.2 and pH 5.0 than did mutants isolated at pH 6.0. At pH 6.0, resistance levels of the mutants isolated at both pH 6.0 and 5.0 were similar. The average generation time for the mutants isolated at pH 6.0 was 54 min, while the average generation time for mutants isolated at pH 5.0 was 77 min.
Effects of soot absorption and scattering on LII intensities in laminar coflow diffusion flames

Abstract Absorption and scattering of laser-induced incandescence (LII) intensities by soot particles present between the measurement volume and the detector were numerically investigated at detection wavelengths of 400 and 780 nm in a laminar coflow ethylene/air flame. The radiative properties of aggregated soot particles were calculated using the Rayleigh–Debye–Gans polydisperse fractal aggregate theory. The radiative transfer equation in emitting, absorbing, and scattering media was solved using the discrete-ordinates method. The radiation intensity along an arbitrary direction was obtained using the infinitely small weight technique. The effects of absorption and scattering on LII intensities are found to be significant under the conditions of this study, especially at the shorter detection wavelength and when the soot volume fraction is higher. Such a wavelength-dependent signal-trapping effect leads to a lower soot particle temperature estimated from the ratio of uncorrected LII intensities at the two detection wavelengths. The corresponding soot volume fraction derived from the absolute LII intensity technique is overestimated. The Beer–Lambert relationship can be used to describe radiation attenuation in absorbing and scattering media with good accuracy provided the effective extinction coefficient is adequately.