cssi/SciSciGPT-SciSciNet huggingface dataset:
B-splines in variational atomic structure calculations

Abstract Many of the problems associated with the use of finite differences for the solution of variational Hartree–Fock or Dirac–Hartree–Fock equations are related to the orthogonality requirement and the need for node counting to control the solution of the two-point boundary value problem. By expanding radial functions in a B-spline basis, the differential equations are replaced by non-linear systems of equations. Hartree–Fock orbitals become solutions of generalized eigenvalue problems where orthogonality requirements can be dealt with through projection operators. When expressed as banded systems of equations, all orbitals may be improved simultaneously using singular value decomposition or the Newton–Raphson method for faster convergence. Computational procedures are described for non-relativistic multiconfiguration Hartree–Fock variational methods and extensions to the calculation of Rydberg series. The effective completeness of spline orbitals can be used to combine variational methods with many-body perturbation theory or first-order configuration interaction. Many options are available for improving atomic structure calculations. Although spline methods are discussed only in connection with non-relativistic theory, they apply equally to Dirac–Hartree–Fock theory.
Systematic Raman study of Tl2Can-1Ba2 CunO4+2n (n=1,2,3) high-temperature superconductors.

We report the results of Raman measurements performed on polycrystalline samples of superconducting Tl/sub 2/Ca/sub n//sub -1/Ba/sub 2/Cu/sub n/O/sub 4+2//sub n/ (n = 1,2,3) with well-characterized transport, magnetic, and structural properties. The room-temperature first-order Raman spectra of polycrystalline samples of predominantly Tl/sub 2/Ba/sub 2/CuO/sub 6/, Tl/sub 2/CaBa/sub 2/Cu/sub 2/O/sub 8/, and Tl/sub 2/Ca/sub 2/Ba/sub 2/Cu/sub 3/O/sub 10/ phases, with respective superconducting transition temperatures of 10, 110, and 125 K display a systematic variation with the number of CuO/sub 2/ layers and great similarities with the Raman spectrum of YBa/sub 2/Cu/sub 3/O/sub 7/. Comparison with Raman spectra of the impurity phase candidates BaCO/sub 3/, BaO/sub 2/, BaCuO/sub 2/, CaCuO/sub 2/, Tl/sub 2/O/sub 3/, and TlCa/sub 5/Cu/sub 6/O/sub x/ allows identification of intrinsic Raman modes of the superconducting phases. Factor group analysis of the three body-centered tetragonal structures space group 14/mmm, yields the mode classifications and the atoms involved in the modes of A/sub 1//sub g/ and B/sub 1//sub g/ symmetry corresponding to c-axis motion that produce the strongest modulation of the polarizability. The systematic variation between the spectra of the three phases and comparison with the well-characterized YBa/sub 2/Cu/sub 5/O/sub x/ Raman spectrum suggests mode assignments for the high-frequency modes ofmore » A/sub 1//sub g/ and B/sub 1//sub g/ symmetry involving oxygen motion.« less
AAAI Leadership Transition

AAAI’s leadership underwent a major change in March of this year. Martha Pollack, who had been serving as AAAI president since July 2009 resigned her position, and Henry Kautz, who had been serving as AAAI president-elect assumed the duties and responsibilities of the president. As stipu- lated in the AAAI bylaws, Kautz will serve in this capacity until the 2010 AAAI annual business meeting, after which he will begin his full two-year term as president, starting one year ahead of schedule. In addi- tion, Eric Horvitz, who has already served one year as AAAI past president, has agreed to serve one addi- tional year so that the position will remain filled throughout Kautz’s tenure as president. An election will be held this year for the now-open position of president elect.
The Political Landscape: Constellations of Authority in Early Complex Polities

The Political Landscape: Constellations of Authority in Early Complex Polities. Adam T. Smith. Berkeley: University of California Press, 2003. 346 pp.
Pigment Changes and Drug Reactions

Medications have long been known to cause pigmentary changes of the skin. While this frequently occurs as post-inflammatory changes of a resolving drug-induced rash, medications can also directly promote dyspigmentation through stimulation of melanin production and/or deposition of drug (or drug metabolite) within the skin. Medications can also cause hypo- or depigmentation. Drug-induced pigmentary changes depend on factors such as the particular drug (or heavy metal) and level of deposition or melanocyte stimulation (or inhibition of melanogenesis). Drug-induced dyschromias have historically been categorized in a medication-class based manner. Because the clinician is generally faced with a patient whose chief complaint is dyspigmentation (which comes in varying shades), we propose a color-based approach for understanding drug-induced dyschromias.
Multiparadigm data structures in Leda

Multiparadigm programming is a term used to describe a style of software development that makes use of facilities originally designed in support of a number of different programming language paradigms. A conception of multiparadigm programming is illustrated by describing how various data structures can be implemented in Leda, a strongly typed compiled multiparadigm programming language. Specifically, a style of program development that draws upon features from a number of different programming language paradigms is illustrated. Aspects of imperative programming, object-oriented programming, functional programming, and logic (or relational) programming are used. It is shown how these various language paradigms can be integrated in a single problem domain, and how each can derive benefit from the others. The problem considered is the creation of a few simple data structures for lists and two-dimensional tables. The development of this example is used as a means to introduce Leda. >
Stable Mycoplasma Antigen Preparations for Indirect Hemagglutination Tests

In immunological studies of mycoplasmas, the use of glutaraldehyde for the fixative makes it possible to use erythrocytes from commercially available defibrinated sheep blood. It eliminates the necessity of having to screen blood from individual sheep to obtain a suitable source of erythrocytes, as when employing tannic acid for fixation and sensitization. The chemical bonding of soluble mycoplasma proteins to glutaraladehyde-fixed sheep erythrocytes by bis-diazotized 3,3′dimethoxy derivative, benzidine, yields preparations that are satisfactory antigens for performing the indirect hemagglutination test by the microtiter technique. The antigenic preparations are satisfactory for use after storage at 4 or -10 C for many months. Incorporation of 5% glycerine in the final suspending milieu makes it possible to obtain uniform suspensions of the fixed and sensitized sheep erythrocytes after freezing and after repeated freezing and thawing. Proteins from Mycoplasma arthritidis and M. hominis have been coupled to glutaraldehyde-fixed erythrocytes by diazotization. The last mentioned preparation detected the presence of antibodies in titers greater than 1:10 in 37% of 237 pregnant women whose ages ranged between 20 and 30 years. There was no correlation between the presence of specific antibodies in the blood and the isolation of M. hominis from the cervical canal.
Radioimmunoassay for the chemical stable prostacyclin analog, 15AU81: a preliminary pharmacokinetics study in the dog

Abstract 15AU81 is a chemically stable tricyclic benzindene analog of prostacyclin, with possible application to the treatment of congestive heart failure. Effective pharmacological doses in a dog model are in the microgram to sub-microgram/kg range, necessitating an analytical method of high sensitivity for determination of the drug in plasma. This report describes the development and validation of a radioimmunoassay for 15AU81, and its application to a pharmacokinetic study in the beagle dog. An antiserum elicited by immunization with a 15AU81-bovine thyroglobulin conjugate was employed, along with 3H-15AU81, in the radioimmunoassay. Analogs of 15AU81, as well as a glucuronide metabolite produced by a dog liver subcellular fraction in vitro, were used to demonstrate the specificity of the radioimmunoassay. Specificity was confirmed by comparative analysis by radioimmunoassay and by a quantitative GC/MS procedure of plasma samples from dogs dosed with 15AU81. The limit of quantitation in dog plasma was 1.6 ng/ml; accuracy and precision were both acceptable. The assay was applied to a study of the pharmacokinetics of 15AU81 in the beagle dog after intravenous or intratracheal administration of a single 20-μg/kg dose. Following intravenous dosing, 15AU81 was eliminated rapidly from plasma ( t 1 2 , 2.8 min), while after intratracheal administration, clearance appeared to be somewhat slower and bioavailability was appreciable (mean, 46%), suggesting that this route of administration may be worthy of further evaluation.
Influence of social setting on the induction of brain cyclic AMP in response to electric shock in the rat

RATS subjected to electric footshock display two disparate behaviours, Escape-attempts or aggressive attack, depending on whether the rat is shocked alone or with a conspecific1. Different responses in blood pressure1, ACTH levels2, and brainstem noradrenaline turnover3 develop in these two patterns of behaviour. On the basis of these studies we hypothesised an additional differential response for brain cyclic AMP levels. We now report a 100% increase in whole brain cyclic AMP following shock-induced fighting but not after identical footshock given to isolated rats. This increase occurred with or without systemic pretreatment of the rats with caffeine, an inhibitor of phosphodiesterase, the enzyme which deactivates cyclic AMP.
The Clinical Utility of Single Balloon Enteroscopy: A Single Center Experience of 172 Procedures

Background Single-balloon enteroscopy (SBE) is a novel endoscopic technique designed to evaluate and treat small-bowel disease. Although there is substantial literature addressing double-balloon enteroscopy and its impact on the diagnosis and management of small-bowel disease, there are limited data available on the clinical utility of SBE. Objectives To evaluate the clinical utility and diagnostic impact of SBE in a large cohort of patients at a single tertiary center. Design Single-center, retrospective study. Setting Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio. Patients A total of 161 patients were referred for SBE from January 2006 to August 2008. Main Outcome Measurements Demographic, clinical, procedural, and outcome data were collected and analyzed. Results A total of 161 patients underwent a total of 172 procedures. Antegrade and retrograde approaches were used in 83% and 17% of subjects, respectively. The average insertion depth using the antegrade approach was 132 cm beyond the ligament of Treitz (range 20-400 cm). The average insertion depth using the retrograde approach was 73 cm above the ileocecal valve (range 10-160 cm). The average procedure time was 40 minutes overall, 38 minutes (range 12-90) antegrade and 48 minutes (range 28-89) retrograde. Fluoroscopy was used in 20 cases (12%). Diagnostic yield was 58% (99/172); 42% (72/172) were therapeutic cases. There were no significant complications. Limitations Single-center, retrospective study. Conclusions SBE demonstrated a high diagnostic yield and frequently provided useful therapeutic intervention. It seems to be a safe and effective method for performing deep enteroscopy.
Joining for Change: An Intervention of State Change or an Interaction of Unforeseen Consequences?

This article is in response to Laurie Charles' (this issue) research article on hostage negotiation. It is suggested that her article provides an opportunity for family therapists to reexamine our own taken-for-granted clinical practices, particularly the practice of joining to achieve rapport. Rapport is considered from the two perspectives of either being an experience of the individual (state trait) or as a dynamic process that is relationally accomplished with unpredictable consequences for both participants. Implications for practice and training are presented.
VI—My Station and its Duties: Ideals and the Social Embeddedness of Virtue

In the Stoics we find a combination of two perspectives which are commonly thought to conflict: the embedded perspective from within one's social context, and the universal perspective of the member of the moral community of rational beings. I argue that the Stoics do have a unified theory, one which avoids problems that trouble some modern theories which try to unite these perspectives.
Antimicrobial susceptibility data and new animal drug approval in the United States: a historical overview

Abstract The requirements and procedures necessary to gain approval for a new animal drug in the United States are briefly reviewed with respect to the requirement and applicability of antimicrobial susceptibility testing data, in particular, as these relate to what is referred to as Professional Flexible Labeled (PFL) animal drugs. The history and process by which the National Committee for Clinical Laboratory Standards (NCCLS) has established internationally recognized and utilized antimicrobial susceptibility testing procedures is reviewed in the context of standardization of procedures used in the clinical veterinary setting. Both the NCCLS and the PFL topics are discussed relative to their applicability to antimicrobial resistance in aquatic species' isolates and their nexus to efforts to begin the process of developing and using standard procedures for aquatic isolates.
Declogging Small-Bore Feeding Tubes

Nine substances (Pancrease, Viokase, pork pancreatin, bromelain, papain, cranberry juice, Coca-Cola, chymotrypsin, and distilled water) were tested every half-hour for 4 hr using 900 mm of water pressure to determine their effectiveness in declogging small-bore feeding tubes. At the end of 4 hr the tubes were irrigated with air using a 50-cc syringe. None of the substances tested were effective within 4 hr. Three substances allowed for successful syringe irrigation at the end of 4 hr. They were: chymotrypsin, papain, and distilled water.
Particle Loading for a Plasma Shear Layer in a Magnetic Field

Some new particle loading methods have been developed for use in simulating a plasma shear layer with nonuniform density and temperature in the presence of a magnetic field, especially with a large effective ion gyroradius. The numerical approach to the shear instability with strong velocity shear consists of starting a simulation from a state of equilibrium, perturbing this equilibrium in some way, then observing the linear growth of the perturbation and its ultimate saturation. With the usual particle loading method, it is difficult to reproduce the equilibrium state if the ion gyroradius is not small on the scale of the shear. The reason is that, with nonuniform velocity shear, i.e., with the nonuniform E-field, a particle may have more than one guiding-center, the particle distribution cannot be obtained analytically, and it may need to be evaluated numerically. If an equilibrium state is not achieved in the particle loading, the shear may relax by means of an "artificial instability" in the course of the simulation, obscuring the physics of interest. With the particle loading method here presented, we simulate a shear layer in a state close to equilibrium without having to solve the Vlasov-Boltzmann equation.
Inference or interaction: social cognition without precursors

In this paper I defend interaction theory (IT) as an alternative to both theory theory (TT) and simulation theory (ST). IT opposes the basic suppositions that both TT and ST depend upon. I argue that the various capacities for primary and secondary intersubjectivity found in infancy and early childhood should not be thought of as precursors to later developing capacities for using folk psychology or simulation routines. They are not replaced or displaced by such capacities in adulthood, but rather continue to operate as our ordinary and everyday basis for social cognition. I also argue that enactive perception rather than implicit simulation is the best model for explaining these capacities.
ON THE FIXED-POINT SETS OF TORUS ACTIONS ON FLAG MANIFOLDS

This paper takes a detailed look at a subject that occurs in various contexts in mathematics, the fixed-point sets of torus actions on flag manifolds, and considers it from the (perhaps nontraditional) perspective of moment maps and length functions on Weyl groups. The approach comes from earlier work of the author where it is shown that certain singular flows in the Hamiltonian system known as the Toda lattice generate the action of a group A on a flag manifold, where A is a direct product of a non-maximal torus and unipotent group. As a first step in understanding the orbits of A in connection with the Toda lattice, this paper seeks to understand the fixed points of the non-maximal tori in this setting.
Fluvastatin titrate‐to‐goal clinical practice study: Interim results

Fluvastatin, the newest addition to the class of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, is structurally different from the other agents. Fluvastatin is the first entirely synthetic IMIG-CoA reductase inhibitor and, compared with the other drugs of its class, has a distinct pharmacologic profile, including short systemic exposure time (half-life of 1.2 h), no active circulating metabolites, and a high degree of protein binding (98%). Fluvastatin is targeted to the liver, with a high rate of absorption (95%). The clinical development of fluvastatin has involved primarily adult patients whose cholesterol levels are in the 95th percentile of the adult population in the United States
Output-feedback sampled-data control design for linear parameter-varying systems with delay

In this paper, we address the sampled-data output-feedback control design problem for continuous-time linear parameter-varying systems with time-varying delay in the system states. Due to the combination of the plant's continuous-time dynamics and the controller's discrete-time dynamics connected through A/D and D/A converter devices, the closed-loop system is a hybrid system. In order to analyse this hybrid system from stability and performance perspectives we use the input-delay approach to map the closed-loop system into the continuous-time domain with delay in the states. This results in a closed-loop system containing two types of delays, the system internal delay and the one imposed by the mapping. Next, we use delay-dependent conditions for analysis of stability and -norm performance which result in a sampled-data control synthesis procedure. The proposed output-feedback sampled-data controller is obtained based on the solution to a linear matrix inequality optimisation problem using a set of appro...
Molecular biology of intracellular protein trafficking

The evidence accumulated to date indicates that protein compartmentalization is mediated through specific regions of proteins destined for translocation into subcellular organelles. Proteins targeted to mitochondria, chloroplasts or the endoplasmic reticulum have ‘transit’ sequences contained in amino-terminal peptide extensions. However, most peroxisomal proteins do not have amino-terminal extensions. Protein importation into mitochondria has been extensively studied and characterized. This post-translational process appears to involve receptors on the mitochondrial outer membrane, and is dependent upon the electrochemical gradient across the inner membrane. Translocation to one of the submitochondrial compartments is determined by the type of transit sequence contained in a mitochondrial protein. The majority of imported mitochondrial proteins are proteolytically altered prior to assembly into oligomeric enzyme complexes. Protein importation into peroxisomes is distinctly different from importation into mitochondria. Although both processes are post-translational, their only other similarity is a requirement for ATP. In this review, we present and compare recent evidence for both mitochondrial and peroxisomal protein importation.
Weight ideals associated to regular and log-linear arrays

Abstract Certain weight-based orders on the free associative algebra R = k 〈 x 1 , … , x t 〉 can be specified by t × ∞ arrays whose entries come from the subring of positive elements in a totally ordered field. If such an array satisfies certain additional conditions, it produces a partial order on R which is an admissible order on the quotient R / I , where the ideal I is a homogeneous binomial ideal called the weight ideal associated to the array. The structure of the weight ideal is determined entirely by the array. This article discusses the structure of the weight ideals associated to two distinct types of arrays which define admissible orders on the associated quotient algebra.
“Forever Kind of Wondering”: Communicatively Managing Uncertainty in Adoptive Families

This study explores the ways in which adoptees experience and manage uncertainty about their adoptive status. Grounded in the interpretive paradigm, the researchers conducted interviews with 25 adopted adults. We determined that the adoptees in this study experienced uncertainty about what their adoption means, details about their birth parents, and their adoptive parents' feelings about the birth parents. Individuals we interviewed were unmotivated, apprehensive, or unable to reduce their uncertainty. Participants reported that their adoptive parents helped them manage uncertainty by discussing the adoption story with adoptees, empowering adoptees to confront their uncertainty, and normalizing the adoption within their family. The findings of the current study extend researchers' understanding of the adoptee experience and of the communicative role of the adoptive parent.
Interactions of fires of neighbouring shrubs in two- and three-shrub arrangements

A physics-based computational model was utilised to better understand the interactions of fires generated by burning of neighbouring shrubs. The model included large-eddy simulation for flow field turbulence and a two-phase approach for the coupling of solid fuel and gas phases. Two different arrangements consisting of two and three identical shrubs placed adjacent to each other were considered. All shrubs were simultaneously ignited from their base with the aid of separate ground fuels. Both crown and ground fuels were modelled as porous media with thermophysical properties of chamise and excelsior respectively. Modelling results indicated that the peak mass-loss rate and the vertical fire spread rate within a shrub decrease when the shrub separation distance increases. At zero separation, heat release rate normalised by the number of shrubs is enhanced by 5 and 15% for the two-shrub and the three-shrub arrangements, respectively. Generation of strong vorticity by higher gravitational torque appeared to be the cause for enhanced burning in the three-shrub arrangement. This effect was seen to be much weaker for the two-shrub arrangement. Interactions between the individual fires cease for a centre-to-centre distance of 1.5 and 2 times the shrub diameter for the two-shrub and the three-shrub arrangement respectively.
Spectral analysis of terrain infrared signatures

Research conducted at Georgia Tech over the past several years has focused on an examination of the signature characteristics of various background materials. These efforts seek to understand the physical basis and features of these signatures in order to aid the development of robust landmine detection techniques. The technical efforts in this study focused on identifying various soil types in LWIR hyperspectral imagery based on spectral characteristics. This paper will discuss the analytical approach and present results from these studies. A discussion of these terrain features as false alarm and clutter sources will also be presented.
Beneficial effect of microinjected trehalose on the cryosurvival of human oocytes.

Abstract Objective: To determine the effectiveness of trehalose as an intracellular cryoprotectant for the cryopreservation of human oocytes. Design: In vitro comparative study. Setting: Clinical and academic research environment at a medical school teaching hospital. Patient(s): Women undergoing in vitro fertilization (IVF). Intervention(s): Discarded human oocytes, obtained from IVF patients, were randomly distributed into three groups: control group (no trehalose), extracellular trehalose group (0.5 M extracellular trehalose), and intracellular trehalose group (0.15 M intra- and 0.5 M extracellular trehalose). Trehalose was introduced into oocytes by microinjection. The oocytes in each group were cooled to different temperatures (i.e., −15°C, −30°C, and −60°C) at rate of 1°C/minute and thawed at ambient air temperature. Survival was examined after overnight culture. Main Outcome Measure(s): Survival of human oocytes cryopreserved in the presence and absence of trehalose. Result(s): The majority of oocytes in the intracellular trehalose group survived cooling to −15°C (63%), −30°C (53%), and −60°C (66%). In contrast, only a small number of oocytes in both the control (13%) and extracellular trehalose group (22%) survived cooling to −15°C, while all oocytes degenerated when cooled to −30°C and −60°C. Conclusion(s): Small amounts of intracellular trehalose in the absence of any other cryoprotectant provide a significant protection against freeze-associated stresses. Our results suggest that sugars such as trehalose should be considered as intracellular cryoprotectants for cryopreservation of human oocytes.
Institutional Repositories: the Library’s New Role

“Institutional repositories” is a new concept for collecting, managing, disseminating, and preserving scholarly works created in digital form by faculty and students in individual universities and colleges. It is born out of problems with the current scholarly communication model structured by commercial journal publishers and vendors. To properly implement these repositories, libraries will need to recruit librarians who possess digital collection management and Open Archive Information System (OAIS) management skills. In addition, training faculty and students to use OAIS, helping them prepare their digital products, involving them in institution‐wide policy making, and setting repository goals would be some of the new tasks that libraries will face.
Taguchi analysis of heat treatment variables on the mechanical behavior of alumina/aluminum metal matrix composites

Abstract Alumina-reinforced aluminum 6061 alloy composites containing 10, 15 and 20 volume percentage particulates were tested using the standard tensile and Charpy impact toughness tests. A statistical approach, known as the Taguchi method, was implemented to identify heat treatment conditions for improved tensile and impact toughness properties. Modulus of elasticity, yield strength, and ultimate tensile strength all increased while impact toughness decreased as a function of the volume percentage of reinforcement for the alumina/aluminum composites in the T6 heat treated condition. Taguchi analysis results indicate that, on average, a 4% increase in yield strength and a 7% increase in ultimate tensile strength over the standard T6 heat treatment can be attained using a heat treatment of 6 h of solutionizing at 529°C and 12–18 h of aging at 160°C. Similarly, using a heat treatment of 2 h of solutionizing at 529°C and 12 h of aging at 127°C results in an impact toughness improvement of more than 87% over the standard T6 heat treatment.
Effect of alkyl chain length on surface silanization of silica

Abstract The effect of the chain length of n-alkyldimethylchlorosilane on surface silanization was extensively studied. The alkyl surface concentration for primary and endcapping silanization were determined using a more accurate gravimetric method instead of the conventional carbon analysis, and the residual hydroxyl groups were detected by a modified Sears' titration method. It was found that there was a linear relationship between the alkyl surface concentration and the number of carbon atoms in the chain of the silane for the primary bonding. It was also found that the total alkyl surface concentration after endcapping remained the same irrespective of the different silanes employed in the primary bonding. It was confirmed that the sum of total alkyl concentration and residual hydroxyl surface concentration equaled the original hydroxyl surface concentration for low-temperature silanization. Compared with previous data, the present study revealed that micropores would consirably decrease the alkyl concentration for long-chain silanes. A size-exclusion mechanism is proposed, tentatively, to interpret the chain-length effect on silanization.
Fork regression is an active helicase‐driven pathway in bacteriophage T4

Reactivation of stalled replication forks requires specialized mechanisms that can recognize the fork structure and promote downstream processing events. Fork regression has been implicated in several models of fork reactivation as a crucial processing step that supports repair. However, it has also been suggested that regressed forks represent pathological structures rather than physiological intermediates of repair. To investigate the biological role of fork regression in bacteriophage T4, we tested several mechanistic models of regression: strand exchange-mediated extrusion, topology-driven fork reversal and helicase-mediated extrusion. Here, we report that UvsW, a T4 branch-specific helicase, is necessary for the accumulation of regressed forks in vivo, and that UvsW-catalysed regression is the dominant mechanism of origin-fork processing that contributes to double-strand end formation. We also show that UvsW resolves purified fork intermediates in vitro by fork regression. Regression is therefore part of an active, UvsW-driven pathway of fork processing in bacteriophage T4.
Restriction in vivo. IV. Effect of restriction of parental DNA on the expression of restriction alleviation systems in phage T4.

Under restricting conditions expression of early T4 genes is determined in part by the location of the particular gene relative to the cleavage site. Some genes are inactivated directly by cleavage of the DNA. Other genes are inactivated by secondary exonucleolytic degradation of cleaved DNA. A third class of genes continues to be expressed from the small fragments which remain after the exonucleolytic degradation of the cleaved fragments. Expression of phage genes coding for the inhibitors of the restriction endonuclease and restriction exonuclease are prevented by endonucleolytic cleavage and exonucleolytic degradation, respectively.
Oxidation of dibenzothiophene by Cunninghamella elegans

The metabolism of dibenzothiophene (DBT) by the catabolically versatile fungusCunninghamella elegans (ATCC 36112) was investigated. This fungus has been previously shown to metabolize polycyclic aromatic hydrocarbons including nitropolycyclic aromatics, but has not been shown to metabolize DBT. The results show thatC. elegans oxidizes DBT to its corresponding DBT-5 oxide and then to DBT-sulfone, without the formation of any biphenyl intermediates.
Computer art graphics integration of art and science

Abstract In an experimental computer art graphics class, students explored geological concepts and processes through creating art. It was examined if students' achievement in geology could be improved by creating art, and how quality of students' artwork may be influenced by their scientific experiences. Analyses of variance and covariance showed significant difference between the mean geology laboratory grades and course final grades for the experimental and the control group. Jurors' evaluations of the students' artwork in the form of a forced q-sort correlated with the order of art creation. The questionnaire answers revealed that the creation of geology-related art provided the students with confidence about their artistic abilities and increased students' understanding of scientific concepts. The results of this study indicated that building representations of scientific concepts through computer art may improve students' achievement in science and enhance their artistic production.
Flow variation in multiple min-cut calculations☆

Abstract A problem of interest in flow networks is that of finding the smallest disconnecting set. Let s, s′, and t be three distinct arbitrary vertices in a directed graph and let τ s,t be the value of the smallest s-t-cut. A method is given for significantly reducing the number of steps needed to calculate τ s,t once τ s′,t has been found by the Ford—Fulkerson labelling algorithm. This new method, called the Flow Variation Algorithm , has been successfully used in finding the smallest disconnecting sets in graphs with up to ninety vertices and eight hundred branches.
A 2.8 Å Fe-Fe separation in the Fe2(III/IV) intermediate, X, from Escherichia coli ribonucleotide reductase.

A class Ia ribonucleotide reductase (RNR) employs a μ-oxo-Fe2(III/III)/tyrosyl radical cofactor in its β subunit to oxidize a cysteine residue ~35 A away in its α subunit; the resultant cysteine radical initiates substrate reduction. During self-assembly of the Escherichia coli RNR-β cofactor, reaction of the protein's Fe2(II/II) complex with O2 results in accumulation of an Fe2(III/IV) cluster, termed X, which oxidizes the adjacent tyrosine (Y122) to the radical (Y122(•)) as the cluster is converted to the μ-oxo-Fe2(III/III) product. As the first high-valent non-heme-iron enzyme complex to be identified and the key activating intermediate of class Ia RNRs, X has been the focus of intensive efforts to determine its structure. Initial characterization by extended X-ray absorption fine structure (EXAFS) spectroscopy yielded a Fe-Fe separation (d(Fe-Fe)) of 2.5 A, which was interpreted to imply the presence of three single-atom bridges (O(2-), HO(-), and/or μ-1,1-carboxylates). This short distance has been irreconcilable with computational and synthetic models, which all have d(Fe-Fe) ≥ 2.7 A. To resolve this conundrum, we revisited the EXAFS characterization of X. Assuming that samples containing increased concentrations of the intermediate would yield EXAFS data of improved quality, we applied our recently developed method of generating O2 in situ from chlorite using the enzyme chlorite dismutase to prepare X at ~2.0 mM, more than 2.5 times the concentration realized in the previous EXAFS study. The measured d(Fe-Fe) = 2.78 A is fully consistent with computational models containing a (μ-oxo)2-Fe2(III/IV) core. Correction of the d(Fe-Fe) brings the experimental data and computational models into full conformity and informs analysis of the mechanism by which X generates Y122(•).
Electrophoretic techniques and genetic variability in hymenoptera

Evidence from both fire ants and honeybee suggests that with proper buffer systems and supporting media some degree of biochemical polymorphism may be found.
Evaluation of a simultaneous sampling method of PAHs, PCDD/Fs and dl-PCBs in ambient air

The Stockholm Convention on Persistent Organic Pollutants (POPs) was signed in May 2001 by 127 countries. Currently, 12 substances are regulated by the convention, and the work on finding new candidate chemicals to the convention has started. Among these 12 substances, dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) are the objects of this study. There are no European standard methods for the simultaneous determination of these microorganic compounds, together with polycyclic aromatic hydrocarbons (PAHs) in ambient air—they must be referred to three different methods developed by the U.S. Environmental Protection Agency (EPA). The quali-quantitative analysis of these microorganic pollutants is an important challenge due to the low concentrations at which they may be present. In this study, the development of a simplified, alternative, fast and affordable sampling method for the determination of PAHs, PCDDs, PCDFs and PCBs in ambient air was performed. The sampling time was extended from 24 h to 7 d in order to enrich the sample, to fall within the instrumental limits of detection and to reduce the number of samples to be processed and, therefore, errors that may arise. First of all, experiments with labelled standards were conducted in the research area of Montelibretti (rural station, which is sited about 20 km northeast of Rome), with the purpose of optimizing sampling efficiency. Finally, the method was applied to the analysis of these compounds in the air of a suburban area with small industrial plants in order to evaluate the feasibility of the proposed sampling method system, by comparing concentrations of native compounds acquired during simultaneous daily and weekly sampling.
Encrustation of nanostructured Ti in a simulated urinary tract environment

The use of materials for medical applications in the urinary tract is hampered by the formation of calcium-based crystalline deposits, generally referred to as encrustation, that act as precursors to urinary stones. Anecdotal evidence suggests that titanium can possess encrustation-resistant properties in vivo and may be useful in urologic applications. To test the utility of coating surfaces with nanostructured titanium, several forms of materials were submersed in artificial urine with saturating concentrations of calcium for a period of 14 days. The specimens were then analyzed using scanning electron microscopy and energy dispersion spectroscopy to determine the extent of encrustation on the surface of the various samples. Our observations indicate that nanostructured titanium offers superior resistance to encrustation when compared to polyurethane, polyvinyl chloride or conventional coarser grained titanium. Further studies investigating the use of nanostructured titanium in urologic applications are warranted.
Echocardiographic M-scan technique in the diagnosis of pericardial effusion.

M-scanning was found useful in eight patients in whom the diagnosis of pericardial effusion was negative or equivocal with conventional echocardiography. With the patient in the semi-recumbent position, the records were obtained while the ultrasound beam was sector scanned base toward the cardiac apex. With this technique, a separation of the posterior pericardium epicardium by a divergent echo-free space was noted when pericardial effusion was present. The divergent nature of the echo-free space was due to accumulation of pericardial fluid toward the cardiac apex. The shift of pericardial fluid toward the cardiac apex was further demonstrated by elevation of the patient supine to the semi-recumbent position. The latter position enhances the sensitivity of M-scanning in the detection of pericardial effusion.
Extending the maternal–zygotic effect with genomic imprinting

Maternal effect refers to the genetic phenomenon in which a phenotype in the progeny is caused by a genetic mutation in the maternal genome rather than a mutation of its own. Maternal effect genes are usually involved in the maternal-to-zygotic transition during embryonic development before zygotic genes are turned on. Although it is widely observed in invertebrate organisms, it is not common in vertebrate animals, especially in mammals. Genomic imprinting is an epigenetic phenomenon that is unique to eutherian mammals, marsupials and plants. One characteristic of genomic imprinting is parental origin-specific expression of imprinted genes. The molecular mechanisms underlying genomic imprinting are poorly understood. Mouse Zfp57 is the first example of a mammalian maternal-zygotic effect gene and it exhibits maternal-zygotic embryonic lethality around midgestation when both maternal and zygotic functions of Zfp57 are absent. Loss of Zfp57 also results in loss of differential DNA methylation at multiple imprinted regions. Interestingly, the midgestational embryonic lethality due to loss of both maternal and zygotic functions of Zfp57 occurs much later than the typically observed maternal-zygotic embryonic lethality during the maternal-to-zygotic transition period in early preimplantation embryos. I hypothesize that gradual loss of heritable genomic DNA methylation imprints over many cell divisions could account for this spatial and temporal discrepancy between the causative molecular defect and the observed phenotype in the Zfp57 mutant.
The detrimental effects of spinal cord injury on spermatogenesis in the rat is partially reversed by testosterone, but enhanced by follicle-stimulating hormone.

Our previous studies have demonstrated that impaired spermatogenesis during the acute phase of spinal cord injury (SCI) is preceded by a transient (but significant) suppression of serum FSH, LH, and testosterone (T) concentrations. It is hypothesized that hormonal deprivation may impair Sertoli cell function, leading to the loss of spermatogonia, degeneration of spermatogenic cells, and eventual regression of the seminiferous epithelium. The current study examined the efficacy of exogenous T and FSH in the maintenance of spermatogenesis and Sertoli cell functions in SCI rats. Implantation of T capsules (TC, 2 × 5 cm) attenuated some of the spermatogenic lesions and maintained qualitatively complete spermatogenesis in all SCI rats 4 weeks after the surgery. In contrast, daily injections of 0.1 U of FSH alone, or in combination with TC implants, paradoxically enhanced the regression of spermatogenesis in SCI rats. At this time, the numbers of Aal, A1, and B spermatogonia and preleptotene spermatocytes in SC...
Stimulation of osteopontin mRNA expression in HL-60 cells is independent of differentiation.

Abstract 12- O -Tetradecanoylphorbol 13-acetate (TPA) induces HL-60 cells to differentiate along the monocyte/macrophage pathway and stimulates expression of the extracellular adhesion protein osteopontin (OPN). In this study, the mechanism of TPA-mediated OPN mRNA expression and its relationship to differentiation were investigated. The induction of OPN mRNA by TPA was dose dependently inhibited by staurosporine (0.4–10.0 n m ) and chelerythrine (0.1–5.0 μ m ), indicating that OPN expression requires PKC activation. Furthermore, the mitogen-activated protein kinase kinase (MAPKK) inhibitor, PD 098059 (1.0–10.0 μ m ), inhibited the effect of TPA in a dose-dependent fashion. Cycloheximide (10 μg/ml) ablated the induction of OPN mRNA by TPA. To determine if OPN mRNA expression was associated with a particular differentiational pathway, HL-60 cells were treated with RA, 9- cis -RA, calcitriol, or sodium butyrate. None of these agents stimulated OPN mRNA. Treatment with TPA subsequent to a 120-h pretreatment with retinoic acid (RA), 9- cis -RA, or calcitriol resulted in a potentiation of the induction of OPN mRNA. These results support a role for protein kinase C (PKC) in promoting OPN expression because each of these agents increased PKC levels. An hOPN promoter/reporter construct was responsive to TPA, indicating that this effect is at the level of transcription. Thus, TPA-stimulated transcription of the OPN gene apparently occurs via a PKC/MAPK-dependent mechanism that is independent of that associated with differentiation and is not dependent on the maturational state of these cells.
Nonablative Radiofrequency for Skin Rejuvenation

There is growing interest in a wide range of nonablative interventions that, predictably, are claimed to rejuvenate skin and subcutaneous tissue “safely and effectively.” Although for many years surgery in its many forms has been the criterion standard treatment in aesthetic aspect of aging, nonsurg
Lack of correlation between para-aminophenol toxicity in vivo and in vitro in female Sprague-Dawley rats.

The present study was designed to test the hypothesis that para-aminophenol (PAP) nephrotoxicity is due to autooxidation. We compared renal functional responses following PAP administration to female Sprague-Dawley rats and following incubation of renal proximal tubules with PAP. The concentrations of PAP selected for in vitro incubations produced cytotoxicity (for example, a decrease in oxygen consumption or adenine nucleotide concentration) in rat renal epithelial cells or rabbit proximal tubule suspensions. In rats, PAP (300 mg/kg i.p.) caused proximal tubular necrosis within 24 hr. Changes in renal function 24 hr following PAP administration included increased kidney weight and blood urea nitrogen concentration and decreased renal glutathione (GSH) content and adenine nucleotide concentrations. PAP did not cause hepatic damage. Within 2-4 hr following PAP administration, renal GSH content and adenine nucleotide concentrations were significantly decreased. In renal cortical slices prepared from PAP-treated rats, oxygen consumption and accumulation of organic ions (para-aminohippurate and tetraethylammonium) were significantly decreased compared with renal cortical slices prepared from control rats. In liver, GSH content was significantly decreased from 1 to 4 hr following PAP administration. In contrast to the effects of PAP in vivo, renal proximal tubules showed little evidence of injury when incubated with 0.1 or 0.5 mM PAP for up to 4 hr in the presence or absence of amino acids in the incubation medium. When tubules were incubated with 1 mM PAP for 4 hr in the presence of amino acids, GSH content, AMP concentration, and TEA uptake were significantly decreased. When amino acids were removed from the incubation medium, 1 mM PAP caused decreases in oxygen consumption and ATP concentration after 4 hr of incubation. Functional changes observed during incubation with PAP in vitro were not consistent with functional changes observed in vivo. The discrepancy between PAP toxicity in vivo and in vitro suggests that autooxidation is unlikely to be responsible for PAP nephrotoxicity and that nephrotoxicity in vivo is primarily mediated by extrarenal bioactivation. Further, depletion of hepatic GSH content prior to changes in renal function suggests that PAP or a PAP metabolite may conjugate with hepatic GSH. These observations suggest that PAP nephrotoxicity may be mediated by PAP-GSH conjugates rather than autooxidation of PAP in the kidney.
Multiplicity of DNA end resection machineries in chromosome break repair

DNA end resection is critical for chromosome break repair by homologous recombination and influences the efficiency of repair by nonhomologous DNA end joining. An elegant study by Sinha and colleagues (pp. 1423-1437) published in the June 15, 2009, issue of Genes & Development identified a novel mycobacterial DNA end resection protein complex, AdnAB, that harbors dual DNA motor and dual nuclease functions. Sinha and colleagues also demonstrated that the DNA end-binding protein complex Ku regulates the activity of AdnAB.
Asymmetric synthesis of enantiopure isoxazolidinone monomers for the synthesis of β3-oligopeptides by chemoselective amide ligation

The design and general synthesis of enantiopure isoxazolidinone monomers as precursors for the preparation of enantiopure N-terminal hydroxylamine-β(3)-oligopeptides, which may be used as reaction partners with α-ketoacids in the decarboxylative amide ligation reaction, is described.
Effect of a highly purified growth hormone on limb regeneration in the hypophysectomized newt, Notophthalmus viridescens

Preparations of ungulate growth hormone that have been used thus far to establish the role of that compound in supporting limb regeneration in hypophysectomized newts have contained significant prolactin contamination. Prolactin when present with thyroxin has been shown to be effective at low doses in supporting limb regeneration in these animals. The present communication demonstrates that a highly purified preparation of bovine growth hormone is able to support limb regeneration in hypophysectomized newts at essentially normal levels. Previous results indicating that prolactin and thyroxin in combination restore the regenerative response are corroborated. Thyroxin alone, or prolactin alone, gave a much reduced response. Purified growth hormone, while effective alone, is apparently antagonized by the presence of thyroxin.