cssi/SciSciGPT-SciSciNet huggingface dataset:
The option of Linac-based radiosurgery in a Gamma Knife radiosurgery center.

Abstract Objective Due to the fundamental differences in treatment delivery, linear-accelerator-based radiosurgery can be complementary to Gamma Knife (GK) for intracranial lesions. We reviewed the effect of adding GK to an existing linear accelerator (Linac)-based radiosurgery practice and analyzed case selections for the two modalities. Patients and methods UC Davis Medical Center installed a Leksell Gamma Knife Model C in October 2003 to supplement an established Linac-based radiosurgery program. Radiosurgery indications for the 15 months before and after installation were compared. Results Radiosurgery cases expanded by twofold from 68 patients before GK installation to 139 after, with 106 treated by GK and 33 by Linac. Besides a major increase for trigeminal neuralgia and a general growth for acoustic neuroma, meningioma and brain metastases, case numbers for glioma and arteriovenous malformation (AVM) remained stable. Considering case selections for Linac, glioma decreased from 28 to 18%, while meningioma and metastases increased from 9 to 21% and 38–46%, respectively. The Linac patients receiving fractionated treatment also increased from 37 to 61%. Conclusions While the majority of patients were treated with GK, a significant proportion was judged to be suited for Linac treatment. This latter group included particularly patients who benefit from fractionated therapy.
Pseudomyxoma peritonei from metastatic colloid carcinoma of the breast

Cystic lesions involving the peritoneum and/or mesentery are uncommon. We present a case of metastatic mucinous adenocarcinoma of the breast to the peritoneum, a new entity to be added to the list of diagnoses that may present with this appearance.
Phase II trials of tyrosine kinase inhibitors in the treatment of chronic myeloid leukemia

Introduction: Chronic myeloid leukemia (CML) is a disease in which outstanding discoveries and achievements have been made over the past two decades. The use of targeted BCR-ABL protein tyrosine kinase inhibitors (TKI) has revolutionized the treatment of this disease and drastically improved its outcomes. Areas covered: Imatinib was the first TKI to be studied and results from the initial IRIS study continues to show major improvement over the historical IFN treatment. More recently, second-generation TKIs, such as dasatinib and nilotinib, and more recently bosutinib proved to be superior to imatinib: higher rates of remission and faster responses. Recently, ponatinib has shown significant efficacy against the most resistant cases of CML, including those who carry the highly resistant T315I mutations. The purpose of this article is to review the data available on different TKIs in the treatment of CML, as well as the emerging data for the treatment of resistant disease. Expert opinion: Early identificatio...
Eliminating traditional reference services in an academic health sciences library: a case study.

Question: How were traditional librarian reference desk services successfully eliminated at one health sciences library?
London theory solutions for the magnetic flux density and the supercurrent density around an elliptical Abrikosov vortex

The formation of an elliptical Abrikosov vortex is energetically favorable in single-crystal YBa/sub 2/Cu/sub 3/O/sub 7/. This consideration has made it possible to obtain London theory solutions for the magnetic flux density and for the supercurrent density around an elliptical vortex that forms with its core axis perpendicular to an anisotropic plane. The anisotropic London equation predicts an effective interchange of penetration depths around the vortex. B is seen to be constant along elliptical contour lines that are commensurate with the interchanged penetration depths. J must vary in magnitude along the same contour lines. >
Internal thoracic artery grafting in the elderly patient undergoing coronary artery bypass grafting: room for process improvement?

Abstract Objective: The acute and long-term benefits of internal thoracic artery grafting are clear in younger patients undergoing coronary artery bypass grafting. The elderly, however, face higher surgical risks and have shorter life expectancy, and thus the use of internal thoracic artery grafting in this age group has been debated. This study examined the use, complication risks, and operative (30-day) mortality associated with internal thoracic artery grafting in patients 75 years of age and older. Methods: Between 1996 and 1999, 522,656 patients in the Society of Thoracic Surgeons National Cardiac Database underwent primary, nonemergency-salvage coronary artery bypass grafting; of these, 99,942 were 75 years of age or older. The influence of internal thoracic artery use on operative mortality and 5 major complications in this elderly group was examined by means of (1) risk adjustment (adjusting for 28 baseline risk factors and site) and (2) a treatment propensity score analysis that compares patients with similar baseline likelihood for receiving an internal thoracic artery graft. Results: In the National Cardiac Database 77.4% of patients aged 75 to 84 years received an internal thoracic artery graft compared with 93.5% for those aged 55 years or less. In this elderly group use of the internal thoracic artery was strongly associated with decreased operative mortality (unadjusted mortality, 6.20% vs 4.05%; P Conclusions: Use of the internal thoracic artery in elderly patients undergoing coronary artery bypass grafting provides an acute survival benefit. This benefit is similar to that seen in younger patients and persists after adjusting for both patient and provider selection factors. The internal thoracic artery appears to be underused in elderly patients undergoing bypass grafting and is a potential area for quality improvement. J Thorac Cardiovasc Surg 2002;123:869-80
The Kingak shale of northern Alaska—regional variations in organic geochemical properties and petroleum source rock quality

Abstract The Kingak Shale, a thick widespread rock unit in northern Alaska that ranges in age from Early Jurassic through Early Cretaceous, has adequate to good oil source rock potential. This lenticular-shaped rock unit is as much as 1200 m thick near the Jurassic shelf edge, where its present-day burial depth is about 5000 m. Kingak sediment, transported in a southerly direction, was deposited on the then marine continental shelf. The rock unit is predominantly dark gray Shale with some interbeds of thick sandstone and siltstone. The thermal maturity of organic matter in the Kingak Shale ranges from immature ( 2.0%R0) in the Colville basin toward the south. Its organic carbon and hydrogen contents are highest in the eastern part of northern Alaska south of and around the Kuparuk and Prudhoe Bay oil fields. Carbon isotope data of oils and rock extracts indicate that the Kingak Shale is a source of some North Slope oil, but is probably not the major source.
Mars rotorcraft: possibilities, limitations, and implications for human/robotic exploration

Several research investigations have examined the challenges and opportunities in the use of small robotic rotorcraft for the exploration of Mars. To date, only vehicles smaller than 150 kg have been studied. This paper proposes to examine the question of maximum Mars rotorcraft size, range, and payload/cargo capacity. Implications for the issue of whether or not (from an extreme design standpoint) a manned Mars rotorcraft is viable are also discussed.
Charged aerosol detection to characterize components of dispersed-phase formulations

Colloidal formulations based on biocompatible phospholipids, emulsifiers, and oils are employed in a wide range of applications including medicine, food, and cosmetics. However, characterization of these dispersed-phase components may be difficult to analyze by traditional HPLC with UV, visible, or fluorescence detection modalities due to lack of chromophores or fluorophores. Charged aerosol detection (CAD) is increasingly used for analysis of dispersed-phase components due to its broad applicability and high sensitivity for non-chromophore containing components found in many colloidal systems, such as lipid-based molecules. In this review, we summarize the recent applications of CAD reported in the literature as well as our own laboratory for the analysis of widely used components of dispersed-phase systems. In particular, we discuss the advantages and disadvantages of CAD compared to other HPLC detection methods, as well as the various sample preparation methods suitable for colloidal formulations prior to HPLC-CAD analysis.
Ganglioside influence on phospholipid films investigated with single molecule fluorescence measurements.

Single molecule fluorescence measurements are used to probe the effects of GM1 in DPPC monolayers. Langmuir–Blodgett films of GM1 and DPPC were doped with ∼10–8 mol % of the fluorescent lipid probe, BODIPY-PC, and transferred onto glass substrates at 23 mN/m. As shown previously, the individual orientation of each BODIPY-PC probe in the membrane can be measured using defocused polarized total internal reflection fluorescence microscopy, revealing changes in film properties at the molecular level. Here, BODIPY-PC tilt angle histograms are used to characterize the effects of GM1 in DPPC films from 0.05 to 100 mol % GM1. At high GM1 levels (>5 mol % GM1), trends in the single molecule measurements agree with previous bulk measurements showing the turnover from condensing to expanding influence of GM1 at 15–20 mol %, thus validating the single molecule approach. At biologically relevant, low concentrations of GM1 (<5 mol % GM1), where bulk fluorescence measurements are less informative, the single molecule me...
Tracking fission-like processes in central collisions of 40Ar+232Th; E = 15–115 A MeV

Abstract Fission-like fragments and coincident charged particles have been measured in a 4π geometry over a wide energy range (15–115 A MeV) for the reaction 40 Ar+ 232 Th. The exclusive folding angle distribution data provide direct evidence that fission-like processes following incomplete-fusion are still an appreciable exit channel for beam energies as high as 115 A MeV.
A STUDY OF FLUID-MEMBRANE INTERACTIONS THAT LIMIT THE OUTPUT OF PERISTALTIC MICROPUMPS

In many microfluidic devices, fluid flow is generated using micropumps like peristaltic micropumps. However the hydrodynamic performance of peristaltic micropumps has not been fully understood and furthermore the effect of dynamic interaction of pumping membrane and fluid flow has not been studied yet. To fill this gap, we studied the hydrodynamic performance of a peristaltic micropump using a numerical model incorporating the fluid-solid interactions. The model consisted of 3 layers; the top layer was the flow channel of 10 μm high, the middle layer was the 5~30 μm thick pumping membrane and the bottom layer was the 3 or 5 pumping chambers. By applying a pumping sequence at a frequency between 16~166 Hz, we calculated flow rate for at least 4 cycles and used the fourth or fifth cycle to evaluate the flow rate per a cycle. We found that the numerical model closely replicated the frequency vs. flow rate relationship of a peristaltic micropump as shown earlier in experimental models. We further found that the flow rate of a peristaltic micropump could be improved by increasing the number of pumping chambers or the thickness of pumping membrane.
Aziridine synthesis in protic media by using lanthanide triflates as catalysts

Abstract Ln(OTf)3-catalyzed aziridine synthesis from imines and diazo compounds was studied in a variety of protic media. The reactions proceeded readily under mild conditions and were highly selective, affording predominantly cis aziridines. The imines used were typically those derived from aromatic aldehydes and aromatic amines, with either electron-donating or electron-withdrawing substituents. N-benzyl aryl aldimines and imines derived from aromatic amines and hindered aliphatic aldehydes were also found to work well. Among the three diazo compounds examined, ethyl diazoacetate (EDA) and 3-nitrophenyl diazomethane were effective reagents for the aziridination. However, the reactions of ethyl diazoacetoacetate failed to give any desired product. Six lanthanides triflates as well as Sc(OTf)3 and Y(OTf)3 were tested as catalyst in the aziridination reaction. The formation of the by-products was also discussed.
Desoxycorticosterone Secretion Rates in Hyperadrenocorticism1

Twelve patients with hyperadrenocorticism have been presented, 3 with primary aldosteronism and 9 with Cushing's syndrome. Three patients (B.F., O.G., J.B.) had increased excretion rates of tetrahydrodesoxycorticosterone (THDOC) and an increased secretion rate of desoxycorticosterone (DOC). Patient B.F. had primary aldosteronism with hypertension and hypokalemic alkalosis. The administration of Aldactone-A resulted in correction of the hypertension, hypokalemic alkalosis, and partial correction of the high Nae: Ke ratio. The urinary excretion rates of 17-ketosteroids and the measured glucocorticoids were normal. There was an increase in the excretion rate of aldosterone as weU as of THDOC and THS. The secretion of both aldosterone and desoxycorticosterone was increased significantly. The cause of the defect in this patient was found to be a primary adrenocortical carcinoma. Removal of the carcinoma resulted in only partial correction of the excessive secretion rate of DOC. One patient with Cushing's syndr...
Height Measurement of Astigmatic Test Surfaces by a Keratoscope That Uses Plane Geometry Surface Reconstruction

Purpose To assess the accuracy with which the Keratron keratoscope (Optikon 2000, Rome, Italy) measured astigmatic test surfaces by a profile reconstruction algorithm within a plane geometry model and to discriminate between error caused by the model and error caused by other factors. Methods Height was reported by the Keratron for eight surfaces with central astigmatism ranging from 4 to 16 diopters. A three-dimensional ray tracing simulation produced theoretic reflected ring patterns on which the Keratron's reconstruction algorithm was performed. The Keratron's measurements were compared with the surfaces' formulas and the ray-traced simulations. Results With a new mathematical filter for smoothing ring data, now part of the Keratron's software, maximum error was 0.47% of the total height and was usually less than 1% of local power for surfaces with 4 diopters of astigmatism. For surfaces with 16 diopters of astigmatism, maximum error was as high as 2.9% of total height and was usually less than 2.5% of local power. The reconstruction algorithm accounted for 40% and 70% of height error, respectively. Conclusions The efficacy of keratoscopes cannot be assumed from their design theories but must be tested. Although plane geometry surface reconstruction contributed greatly to total height error, total error was so small that it is unlikely to affect clinical use.
A note on nonnegative rank factorizations

Abstract A nonnegative weakly monotone matrix of rank r has a nonnegative rank factorization if and only if it possesses an r x r monomial submatrix.
Progress in liquid-metal fast breeder reactor safety research and development—An overview of the issues

Abstract The safety of Liquid-Metal Fast Breeder Reactors has been the subject of massive world-wide research and development. This paper attempts to give a brief overview of the R & D directed toward an understanding of those events that could contribute to the release and transport of fission products and transuranic elements up to the boundary of the reactor secondary containment system.
Further tests of permeability with low hydraulic gradients

Many of the water-bearing formations in the United States have hydraulic gradients of much less than 20 feet to the mile, and some may have gradients of less than one foot to the mile, whereas most laboratory-tests of permeability are made with much higher gradients. An investigation was therefore undertaken by the writer, under the direction of 0. E. Meinzer, in the Hydrologic Laboratory of the United States Geological Survey, to determine whether Darcy's law is valid for very low hydraulic gradients—that is, whether under such low gradients the rate of flow remains proportional to the gradient. In a previous paper by Meinzer and the writer (Amer. Geophysical Union,15th annual meeting, pp.405–409, 1934), it was shown that for the sand tested the rate of flow varies directly with the hydraulic gradient down to a gradient of about one foot to the mile. More recently six additional tests have been made on this sand with the same apparatus, and these tests give evidence of the validity of Darcy's law for still lower gradients.
On the necessary and sufficient conditions for Nash implementation

The purpose of this paper is to provide a constructive way of checking whether or not a social choice correspondence can be implemented in Nash equilibria. The results apply when there are two or more players. The usefulness of this constructive approach is illustrated for the case of single-peaked preferences over ℝ, a two-person public good economy with monotonic preferences, and a two-person exchange economy with monotonic preferences.
Understanding the tempo-spatial limits of information dissemination in multi-channel Cognitive Radio Networks

Cognitive Radio Networks (CRNs) have emerged to become promising network components for exploiting spectrum opportunistically in order that information can be delivered in circumstances otherwise impossible. Challenging yet open questions are how fast and how far a packet can be delivered in such networks, in temporal and spatial domains, respectively. The answers to these questions offer a straightforward interpretation of the potentials of CRNs for time-sensitive applications. To tackle these questions, we define two metrics, dissemination radius ∥ℒ(t)∥ and propagation speed S(d). The former is the maximum Euclidean distance that a packet can reach in time t, and the latter is the speed that a packet transmits between a source and destination at Euclidean distance d apart, which can be used to measure the transmission delay. Further, we determine the sufficient and necessary conditions under which there exist spatial and temporal limits of information dissemination in CRNs. We find that when information cannot be disseminated to the entire network, the limiting dissemination radius is statistically dominated by an exponential distribution, while the limiting information propagation speed approaches to zero. Otherwise, the dissemination radius approaches to infinity and the propagation speed S(d) is no lower than some constant k for large d. The results are validated through simulations.
Decision making in academia: A case of the dean selection process

This study describes the use of the analytical hierarchy process (AHP) in the dean selection process. A subcommittee of the dean search task force created an order-ranking based upon group discussions as well as through the application of the AHP. The results of the two processes were compared against the Provost's final decision. Discrepancies were analyzed and explained. The results suggest that root cause of the differences was a variation in emphasis on certain criteria. The authors conclude that AHP is a valuable tool and should be incorporated into personnel selection processes in academia. The AHP provides a convenient and effective tool for evaluating personnel. Fears that it might prove overly complex or difficult for non-technical people to use proved to be unfounded.
Structural differences between Pb2+- and Ca2+-binding sites in proteins: Implications with respect to toxicity

Pb(2+) is known to displace physiologically-relevant metal ions in proteins. To investigate potential relationships between Pb(2+)/protein complexes and toxicity, data from the protein data bank were analyzed to compare structural properties of Pb(2+)- and Ca(2+)-binding sites. Results of this analysis reveal that the majority of Pb(2+) sites (77.1%) involve 2-5 binding ligands, compared with 6+/-2 for non-EF-Hand and 7+/-1 for EF-Hand Ca(2+)-binding sites. The mean net negative charge by site (1.7) fell between values noted for non-EF-Hand (1+/-1) and EF-Hand (3+/-1). Oxygen is the dominant ligand for both Pb(2+) and Ca(2+), but Pb(2+) binds predominantly with sidechain Glu (38.4%), which is less prevalent in both non-EF-Hand (10.4%) and EF-Hand (26.6%) Ca(2+)-binding sites. A comparison of binding geometries where Pb(2+) has replaced Ca(2+) in calmodulin (CaM) and Zn(2+) in 5-aminolaevulinic acid dehydratase (ALAD) revealed protein structural changes that appear to be unrelated to ionic displacement. Structural changes observed with CaM may be related to opportunistic binding of Pb(2+) in regions of high electrostatic charge, whereas ALAD may bind multiple Pb(2+) ions in the active site. These results suggest that Pb(2+) adapts to structurally-diverse binding geometries and that opportunistic binding may play an active role in molecular metal toxicity.
Meeting RTP Temperature Accuracy Requirements: Measurement and Calibrations at Nist

Although radiometric temperature measurement in rapid thermal processing (RTP) tools has substantially improved in terms of repeatability and uniformity, it still remains a technical challenge. The 1999 requirements of 180 nm line width technology in the 1997 National Technology Roadmap for Semiconductors (NTRS) imply an uncertainty of ± 2 °C in temperature measurement, which will continue the challenge in temperature measurement. In this paper we will discuss the NIST absolute radiometric temperature calibration, measurements, and uncertainty analysis.
The Ternary System CaO—MnO—SiO2

Phase equilibrium data resulting from quenching experiments are presented for the ternary system CaO-MnO-SiO2. An atmosphere of controlled oxygen pressure having Po2, ≅ 10−6 atm at 1555°C was used to maintain the manganese in the divalent state. The ternary liquidus surface is largely one of low-lying liquidus temperatures. Three ternary liquidus minima dominate this surface. These have the following compositions (in weight percent CaO, MnO, and SiO2): (a) 5.0, 48.4, and 46.6%, (b) 17.5, 45.0, and 37.5%, and (c) 15.0, 53.0, and 32.0%. Temperatures measured at these points are (a) 1265° C, (b) 1195°C, and (c) 1204°C. Isofracts of the quenched glasses are presented. Crystallization paths of ternary mixtures are represented by a series of fractionation curves and selected isothermal planes. Partition of manganese between coexisting pairs of crystalline phases (e.g., meta-silicate, olivine, and (Ca,Mn)O solid solutions) favors concentration of manganese in the more basic phase. Subsolidus equilibria involving these phases and also Ca3Si2O7 and Ca3SiO5 are discussed. Ca3Si2O7 and Ca3SiO6 do not admit any appreciable amounts of Mn++ into their lattices.
Where in the World am I? Sex and Handedness Differences in Knowledge of Geography

218 college students (96 men and 122 women, including nearly equal numbers of right-handers and left-handers) were administered a modified version of the "Gallup Geography Test." Men outperformed women, and left-handed women outperformed right-handed women. We suggest that these results cannot be easily explained by any credible sociocultural model but are consistent with a neuropsychological model of sex and handedness differences in spatial ability advanced by Harshman, Hampson, and Berenbaum in 1983.
Carbohydrate antigens and lectin receptors of the plasma membrane of carrot cells

A monoclonal antibody (JIM 1) has been derived, subsequent to immunization of rats with carrot protoplasts and a hybridoma screen of protoplast immunoagglutination, that recognizes a determinant at the outer face of the plasma membrane of carrot cells. The binding of JIM 1 is readily inhibitable by β-D-galactosyl residues. Although weakly cross-reacting with an extracellular arabinogalactan protein, isolated from the conditioned medium of suspension-cultured carrot cells, JIM 1 does not recognize arabinogalactan proteins associated with the plasma membrane. The plasma membrane antigen recognized by JIM 1 was of low molecular weight and was sensitive to both periodate treatment and a protease. JIM 1 therefore defines a new class of galactosyl-residue containing plant cell surface antigen, distinct from the arabinogalactan proteins. However, the extracellular arabinogalactan protein and related plasma membrane-associated glycoproteins are demonstrated to bind the anti-galactose plant lectin peanut agglutinin.
Regulation by cyclic AMP of the genes encoding steroidogenic enzymes: when the light finally shines...

Article synthese considerant les donnees recentes concernant les mecanismes de la regulation de l'expression des genes, codant pour les principales enzymes impliquees dans la steroidogenese, par l'AMPcyclique
Photoconductivity in amorphous Sb1−xSex layers

The photoconductive spectral response of amorphous Sb1−xSex films as a function of composition shows that an excess of Sb or Se causes a shift toward smaller or larger activation energies, respectively, when compared with stoichiometric Sb2Se3 films (x=0.60). This shift agrees with the shift of the optical absorption edge. An estimate of the density of states at the quasi-Fermi level for amorphous Sb2Se3 gives values of at least 104 greater than the single crystal material.
Visualisation of wormholes in underwater sensor networks: a distributed approach

We propose a distributed mechanism, Dis-VoW, to detect wormhole attacks in underwater sensor networks. In Dis-VoW, every sensor reconstructs local network layout using multi-dimensional scaling. It detects the wormholes by visualising the distortions in edge lengths and angles among neighbouring sensors. The contributions include: Dis-VoW does not depend on any special hardware; it provides a localised wormhole detection mechanism adapting to network topology changes; it integrates techniques from social science and scientific visualisation to attack network security problems. The simulation results show that Dis-VoW can detect most of the fake neighbour connections without introducing many false alarms.
Uptake of glucose dependent on insulin in the isolated bladder of the toad.

THE biological behaviour of the isolated toad bladder has been of considerable recent interest1–3. In the non-stimulated state this tissue is characterized by low permeability to water and a variety of small molecules2, as well as active sodium transport from the mucosal to the serosal surface. The addition of both vasopressin and its related peptides markedly alter these characteristics by increasing permeability to water and urea as well as active sodium transport2. Although some attention has been directed to the metabolic interrelations between the intermediary metabolism of the tissue and active sodium transport4,5, no systematic investigation of glucose penetration has been conducted. This report presents data which establish that the isolated toad bladder is capable of glucose uptake from the medium in which it is incubated and that the glucose uptake is stimulated in the presence of insulin.
Minimum probability of error for asynchronous Gaussian multiple-access channels

Consider a Gaussian multiple-access channel shared by K users who transmit asynchronously independent data streams by modulating a set of assigned signal waveforms. The uncoded probability of error achievable by optimum multiuser detectors is investigated. It is shown that the K -user maximum-likelihood sequence detector consists of a bank of single-user matched filters followed by a Viterbi algorithm whose complexity per binary decision is O(2^{K}) . The upper bound analysis of this detector follows an approach based on the decomposition of error sequences. The issues of convergence and tightness of the bounds are examined, and it is shown that the minimum multiuser error probability is equivalent in the Iow-noise region to that of a single-user system with reduced power. These results show that the proposed multiuser detectors afford important performance gains over conventional single-user systems, in which the signal constellation carries the entire burden of complexity required to achieve a given performance level.
Modifications Induced in the sexual Cycles of the Protozoa of Cryptocercus by Chabge of Host

SYNOPSIS. The following types of transfauntions were made: from nymphs is an early stage of their molting period to nymphs 1-50 days before ecdysis and vice versa; from recently molted nymphs to nymphs in all stages of the molting period and vicve versa. In such transfaunated half or more of the protozoa in a donor host were transferred to a recipient host. The recipient hosts wee defaunated with oxygen by subjecting them to 60 psi for 2 hours, twice the minimum time necessary to kill all their protozoa. Transfaunations were made 24 hours after defaunation. The sexual cycles, as a result of these transfaunation experiments, in addition to being prevented altogether in several genera, were modified principally in two ways: they were shortened to less than half the time required under natural conditions; they were lengthened, in some genera, from two days to over two months. Whether shorteing or lengthening occurs depends on the type of host used in the experiment. And the factor in the host that is responsible for the modifications is the ecdysone titer; transfaunation from a lower to higher to a lower titer, in general, serves to lengthen it.
Theory of Substituent Effects on Pericyclic Reaction Rates: Alkoxy Substituents in the Claisen Rearrangement

Transition structures, activation energies, and reaction energies were calculated by ab initio quantum mechanical methods for the Claisen rearrangements of five hydroxy-substituted allyl vinyl ethers. The RHF, DFT(Becke3LYP), and CASSCF methods with the 6-31G* basis set were carried out. There is good agreement with activation energies measured for alkoxy-substituted compounds. The activation energies were separated into thermodynamic and intrinsic effects using Marcus theory as adapted by Murdoch for pericyclic reactions. Intrinsic effects were analyzed by frontier molecular orbital theory. The deuterium kinetic isotope effects calculated at the CASSCF/6-31G* level for the 2-OH allyl vinyl ether are in good agreement with the experimental results for the 2-OSiMe3 derivative, and these calculated isotope effects show much more bond-breaking and less bond-making than those at both the RHF/6-31G* and Becke3LYP/6-31G* levels.
The role of Lmx1a in the differentiation of human embryonic stem cells into midbrain dopamine neurons in culture and after transplantation into a Parkinson's disease model.

Recent studies have provided important insight into the homeoprotein LIM homeobox transcription factor 1{alpha} (Lmx1a) and its role in the commitment of cells to a midbrain dopamine (mDA) fate in the developing mouse. We show here that Lmx1a also plays a pivotal role in the mDA differentiation of human embryonic stem (hES) cells. Thus, as indicated by small interfering RNA experiments, the transient early expression of Lmx1a is necessary for the coordinated expression of all other dopamine (DA)-specific phenotypic traits as hES cells move from multipotent human neural progenitor cells (hNPs) to more restricted precursor cells in vitro. Moreover, only Lmx1a-specified hNPs have the potential to differentiate into bona fide mDA neurons after transplantation into the 6-hydroxydopamine-treated rat striatum. In contrast, cortical human neuronal precursor cells (HNPCs) and mouse subventricular zone cells do not express Lmx1a or become mDA neurons even when placed in an environment that fosters their DA differentiation in vitro or in vivo. These findings suggest that Lmx1a may be critical to the development of mDA neurons from hES cells and that, along with other key early DA markers (i.e., Aldh1a1), may prove to be extremely useful for the selection of appropriately staged and suitably mDA-specified hES cells for cell replacement in Parkinson's disease. STEM CELLS 2009;27:220-229
The Infrared Colors of Main Sequence Stars: How Much Circumstellar Debris Is Normal?

We have been awarded NASA Key Project observing time on ISO, in order to establish the true frequency of far-infrared excesses in a volume-limited sample of main sequence and related stars, and address the relative success or failure of single stars in processes related to the forming of planetary systems. For a volume-limited subset of main sequence and related stars, PHT03 measurements at 3.6, 11.5, 20 and 60 micron will be obtained, using a 120 arsec aperture in all cases to eliminate possible companion confusion with differing apertures, to ascertain spectral energy distributions. For the M dwarfs, 100 micron observations will also be obtained. For some, brighter sources, more extensive wavelength coverage and improved spatial resolution will be attempted, using CAM and SWS. Spatially over-sampled PHOT observations will be made at 60 micron of the brightest and nearest Vega-like sources to measure the characteristic sizes of the emitting regions and obtain some information regarding their shapes and orientations. The goal is not a map, but scan profiles along 3 position angles which can be deconvolved to find the intrinsic size and shape of the half-maximum contour of the emitting region. Photometry of selected lines of sight through the zodiacal dust will also be carried out to look for outer solar system (Kuiper Belt) material. Observation at a range of wavelengths, ecliptic latitudes and at 2 epochs is designed to help untangle foreground Zodiacal from background Kuiper flux, not necessarily to look for individual macroscopic objects.
Peakedness and peakedness ordering

The peakedness of a random variable (RV) X about a point a is defined by P"a(x)=P(|X-a|@?x),x>=0. A RV X is said to be less peaked about a than a RV Y about b, denoted by [email protected]?"p"k"d"("a","b")Y, if P(|X-a|@?x)@?P(|Y-b|@?x) for all x>=0, i.e., |X-a| is stochastically larger than |Y-b|. These generalize the original definitions of Birnbaum (1948) [2] who considered the cases where X and Y were symmetric about a and b, respectively. Statistical inferences about the distribution functions of continuous X and Y under peakedness ordering in the symmetric case have been treated in the literature. Rojo et al. (2007) [12] provided estimators of the distributions in the general case and analyzed their properties. We show that these estimators could have poor asymptotic properties relative to those of the empiricals. We provide improved estimators of the DFs, show that they are consistent, derive the weak convergence of the estimators, compare them with the empirical estimators, and provide formulas for statistical inferences. An example is also used to illustrate our theoretical results.
Relationship of dielectric property change to composite material state degradation

Abstract Polymer matrix composites are widely used in many industries, i.e. aerospace, microelectronics, energy storage etc., because of their unique properties and performance. During their service life, changes of material state caused by deformation and damage accumulation under combined mechanical, thermal and electrical fields requires fundamental understanding to support design of those material systems. Heterogeneous material systems are inherently dielectric as determined by their complex morphology. Dielectric properties of such materials are altered by many factors, e.g., electrical and structural interactions of the particles, and the shape, orientation and distribution of the constituents of the material system. When damage occurs, new phases are created as micro-defects, and grow progressively, interact, and accumulate. The dielectric properties of the composite system also change in a manner that uniquely reflects those details. In the present work we report a non-invasive, in-operando technique to study changes in dielectric properties during progressive damage accumulation in composite materials subjected to mechanical loading.
Hypothermic effects of apomorphine homologues in mice

A single intraperitoneal (i.p.) injection in mice of apomorphine (I) and its analogues norapomorphine (II), N-ethylnorapomorphine (III), N-n-propylnorapomorphine (IV) and apocodeine (V), caused dose-related decreases in deep-core body temperature. The neuroleptic agent haloperidol blocked the hypothermia produced by these apomorphines but alpha-methyl-p-tyrosine failed to do so. This indicated a direct post-synaptic stimulation of dopamine receptors. Methysergide potentiated the hypothermic effect of the apomorphine analogues. Taking the amount of apomorphine to produce a 3 degree C fall in temperature at 30 min as unity, the approximate relative potencies were: I 1.00, II 0.06, III 47.50, IV 85.00, V 0.340. The doses of the apomorphines needed to produce hypothermia were much less than those needed to cause stereotypy. The ratios of the minimal doses required to produce hypothermia, to those producing stereotypy were: I 8.82, II 4.00, III 125.00, IV 28.50, V 1.43.
Evidence from thymidine labeling for continuing growth of retina and tectum in juvenile goldfish

Tritiated thymidine was injected intraperitoneally into juvenile goldfish that were 3 to 6 cm in body length. After 6 h to 32 months these fish were then killed for autoradiography of retina and tectum. The autoradiographs indicated that despite the maturity of these goldfish both retina and tectum were still growing by the accretion of new cells at their margins. As was shown for Xenopus, new retinal cells were added around the entire retinal circumference, while new tectal cells were added principally around the posterior tectal margin and none to the anteriormost edge. However, goldfish of this size have a well-defined and functional retinotopic projection of retina onto tectum. This means that newly created ganglion cells of temporal retina, destined to send axons to anterior tectum, will find only old tectal cells at their target locus with which to connect. Presumably preexisting retinal terminals in the tectum must be shifted posteriorly to allow the new ganglion cells to find tectal synaptic sites.
2-Deoxy-D-Glucose Treatment of Endothelial Cells Induces Autophagy by Reactive Oxygen Species-Mediated Activation of the AMP-Activated Protein Kinase

Autophagy is a cellular self-digestion process activated in response to stresses such as energy deprivation and oxidative stress. However, the mechanisms by which energy deprivation and oxidative stress trigger autophagy remain undefined. Here, we report that activation of AMP-activated protein kinase (AMPK) by mitochondria-derived reactive oxygen species (ROS) is required for autophagy in cultured endothelial cells. AMPK activity, ROS levels, and the markers of autophagy were monitored in confluent bovine aortic endothelial cells (BAEC) treated with the glycolysis blocker 2-deoxy-D-glucose (2-DG). Treatment of BAEC with 2-DG (5 mM) for 24 hours or with low concentrations of H2O2 (100 µM) induced autophagy, including increased conversion of microtubule-associated protein light chain 3 (LC3)-I to LC3-II, accumulation of GFP-tagged LC3 positive intracellular vacuoles, and increased fusion of autophagosomes with lysosomes. 2-DG-treatment also induced AMPK phosphorylation, which was blocked by either co-administration of two potent anti-oxidants (Tempol and N-Acetyl-L-cysteine) or overexpression of superoxide dismutase 1 or catalase in BAEC. Further, 2-DG-induced autophagy in BAEC was blocked by overexpressing catalase or siRNA-mediated knockdown of AMPK. Finally, pretreatment of BAEC with 2-DG increased endothelial cell viability after exposure to hypoxic stress. Thus, AMPK is required for ROS-triggered autophagy in endothelial cells, which increases endothelial cell survival in response to cell stress.
Computational modeling of metal matrix composite materials—III. Comparisons with phenomenological models

Abstract The mechanical behavior of particulate reinforced metal matrix composites, in particular an SiC reinforced Al-3 wt% Cu model system, was analyzed numerically and analytically. In this, the third article in a series, the results of the computational micromechanics are compared with those of simpler and more approximate analytical/numerical models. The simplerapproaches considered use phenomenological theories of plasticity and power-law strain hardening. Models that predict overall composite behavior make use of a result, valid for incompressible materials in small strain, that both pure matrix material and composite harden with the same hardening exponent. Results of micromechanical simulations, with power-slip system hardening, show that in a very approximate sense over restricted strain regions, power-law slip hardening is preserved with the power-law exhonent tending to increase with volume fraction. The results of the computations presented in the previous article are compared with the predictions of one such analytical/numerical model, where the matrix hardening function is fitted to the unreinforced poyycrystal stress-strain response. This model employs the self-consistent method to quantify strengthening. There is good agreement between the computed and predicted results. Simulations are performed using existing reinforcement geometry but replacing the physically based crystal plasticity theory with the phenomenologically based J2 flow theory. The results are in good qualitative agreement with those of the original crystal plasticity simulations at both the microscale and the macroscale. Deformation patterns in the J2 flow theory composites are smoother and tend to be less localized than those in the crystal plasticity composites; however, these features depend strongly on volume fraction and morphology. The J2 flow theory composites display power-law exponents whose dependence on overall strain, volume fraction and morphology are much more easily characterized than in the crystal plasticity case.
Structures of Cyanobactin Maturation Enzymes Define a Family of Transamidating Proteases

Cyanobactins, a class of ribosomally encoded macrocylic natural products, are biosynthesized through the proteolytic processing and subsequent N-C macrocylization of ribosomal peptide precursors. Macrocylization occurs through a two-step process in which the first protease (PatA) removes the amino terminal flanking sequence from the precursor to yield a free N terminus of the precursor peptide, and the second protease (PatG) removes the C-terminal flanking sequence and then catalyzes the transamidation reaction to yield an N-C cyclized product. Here, we present the crystal structures of the protease domains of PatA and PatG from the patellamide cluster and of PagA from the prenylagaramide cluster. A comparative structural and biochemical analysis of the transamidating PatG protease reveals the presence of a unique structural element distinct from canonical subtilisin proteases, which may facilitate the N-C macrocylization of the peptide substrate.
Kniest dysplasia. A histochemical study of the growth plate.

Summary: Chondro-osseous tissue from four patients with the Kniest dysplasia was studied histochemically using a new plastic embding technique. Extensive vacuolar changes were observed p-1 throughout the endochondral growth plate and adjacent resting cartilage. These changes occurred within the cartilage matrix and also in the lacunae of degenerating chrondrocytes. The septa of the lesions contained chondroitin sulfate, but little keratan sulfate or collagen. Resting cartilage not adjacent to the growth plate stained irregularly and showed few of the vacuolar lesions, and chondrocytes were enlarged and contained cytoplasic inclusions, but no vacuolar material. Thus, there appears to be a sequence of events initiated by cellular accumulation of a substance and progressing to cellular and matrix degeneration. Speculation: The findings suggest that there may be a defect in the synthesis, structure, or secretion of a major cartilage matrix component (e.g, proteoglycan, collagen) which leads to its accumulation in the chondrocyte rough endoplasmic reticulum. Both cellular and matrix degeneration subsequently occur either due to a toxic effect of this material or to the absence of the normal molecule.
BEHAVIORAL TRAINING FOR SIBLINGS OF AUTISTIC CHILDREN

The present study was conducted to investigate the effectiveness of a program designed to teach behavior modification procedures to normal siblings of autistic children. Three sibling pairs participated in a multiple-baseline analysis of the effects of training the normal siblings to use behavior modification procedures to teach their autistic brother or sister a variety of learning tasks. Results indicated that the siblings learned to use the behavioral procedures at a high level of proficiency, they used the procedures in a generalization setting, and there were observed improvements in the behavior of the autistic children. In addition, a social validation assessment of the normal siblings' statements about their autistic sibling indicated a decrease in negative statements and an increase in positive statements after training. These results are discussed in terms of the potential for incorporating siblings into the treatment plan in intervention programs with autistic children.
The Social and Cultural Predictors of Generosity in Marriage: Gender Egalitarianism, Religiosity, and Familism

This study focuses on the social and cultural sources of an important dimension of solidarity in contemporary marriages: marital generosity. Marital generosity is defined here as freely giving to one’s spouse by regularly engaging in small acts of service, forgiving one’s spouse, and displaying high levels of affection and respect. Using recent data from a national sample, the Survey of Marital Generosity (N = 1,368 couples), we explored the associations between gender egalitarianism, familism, religiosity, and generous behavior among spouses aged 18 to 45. Our results suggest that domestic gender egalitarianism—where spouses reported sharing housework and child care—is linked to greater reports of marital generosity. Religiosity is also positively associated with marital generosity. Finally, the most potent predictor of generosity in this study is commitment, where spouses are personally dedicated to their partner and to continuing the relationship.
Effect of Chronic Nortriptyline Pretreatment on the Acute Toxicity of Various Medicinal Agents in Rats

A method using rats that can be of value in predicting the effects of chronic treatment with psychotherapeutics on the acute toxicity of other medicinal agents is described. Results obtained by this method showed that noruiptyline, like amitriptyline, enhanced the toxicity of most cerebral depressants in an additive manner. Both of the antidepressive compounds were shown to markedly potentiate the toxicity of physostigmine and to a lesser degree pilocarpine. Ephedrine toxicity was significantlly antagonized by thymoleptic pretreatment. The test failed to verify reports that the tricyclic antidepressives dangerously potentiate the toxicity of alcohol or nionoamine oxidase inhibitors. Results indicated that a variety of medicinal agents can he used in the nortriptyline treated patient without any problem of significant drug interaction.
Differentiation in sex investment by clones and populations of Daphnia

Dormancy is an ecological strategy by which organisms avoid stressful environments, but it also can have genetic consequences. Many facultative parthenogens shift from asexual to sexual reproduction to enter dormancy. Hence, conditions that favour dormancy are predicted to select for more sex, which should increase clonal diversity. We examined lake populations of Daphnia that face different ecological risks to remaining active year-round, and quantified the extent to which they have differentiated in their investment in dormancy and sex. There was substantial genetic variation among populations and clones for sex induction and production of dormant eggs, and striking evidence of gender specialization. We also observed a positive association between the magnitudes of population-level investment in dormancy and of variance among clones in sex induction. These results document an ecological gradient in dormancy that is manifest as a genetic gradient in clonal variation for the propensity to engage in sex.