cssi/SciSciGPT-SciSciNet huggingface dataset:
Capping Tax-Preferred Retirement Contributions: Preliminary Evidence of the Impact of the National Commission on Fiscal Responsibility and Reform Recommendations

In December 2010, the National Commission on Fiscal Responsibility and Reform released their long-awaited document on federal debt reduction, “The Moment of Truth.” Although their guiding principles and values (pages 13-14) specifically mention the need to keep America sound over the long run by implementing “policies today to ensure that future generations have retirement security, affordable health care, and financial freedom,” the document puts forth a tax reform plan that would modify retirement plans by capping annual “tax-preferred contributions to [the] lower of $20,000 or 20% of income” (page 31). This is often referred to as the “20/20 cap.” Even if one were to ignore the potential interaction of the proposed limitations with the present values of accruals under defined benefit plans and/or the existing tax preferences available to some individual retirement account (IRA) contributions, this alternative formulation of capping tax-preferred contributions would substantially reduce the current limits available under qualified defined contribution (401(k)-type) plans. Currently, the combination of employee and employer contributions is the lesser of a dollar limit of at least $49,000 per year and a percentage limit of 100 percent of an employee’s compensation. This paper provides preliminary evidence of the impact of these “20/20 caps” on projected retirement accumulations under a set of assumptions explained in detail. New results from EBRI’s Retirement Security Projection Model™ (RSPM) show that the highest-income quartile within each age cohort would see the largest average percentage reduction in projected balances at retirement. However, for each age cohort other than the oldest one, the lowest-income quartile would see the second-highest average percentage reductions. Phrased another way, the proposed cap would, as expected, most affect the highest-income workers; but it also would cause a very big reduction in projected retirement accumulations for the lowest-income workers. While the results presented in this paper provide a first approximation of the potential impact of these constraints on workers, as well as the distribution of the impact by income, they do not tell the entire story. A follow-up study will also explore the likely impact of these constraints on retirement plan sponsor behavior and estimate the extent to which fewer employers would be willing to offer qualified defined contribution plans (especially among plans offered by small employers). The PDF for the above title, published in the July 2011 issue of EBRI Notes, also contains the fulltext of another July 2011 EBRI Notes article abstracted on SSRN: “The Impact of the Recession on Employment-Based Health Benefits: The Case of Union Membership.”
High-dose carboplatin, thiotepa, and etoposide with autologous stem-cell rescue for patients with recurrent medulloblastoma. Children's Cancer Group.

PURPOSEMedulloblastoma is a highly lethal disease when it recurs. Very few patients survive with conventional treatment. This study evaluated the use of high-dose carboplatin, thiotepa, and etoposide with autologous stem-cell rescue (ASCR) in patients with recurrent medulloblastoma.METHODSChemotherapy consisted of carboplatin 500 mg/m2 (or area under the curve = 7 mg/mL x min via Calvert formula) on days -8, -7, and -6; and thiotepa 300 mg/m2 and etoposide 250 mg/m2 on days -5, -4, and -3; followed by ASCR on day 0. In addition to the study-prescribed therapy, 21 patients received other treatment: neurosurgical resection in seven, conventional chemotherapy in 17, and external-beam irradiation in 11 cases.RESULTSTwenty-three patients with recurrent medulloblastoma, aged two to 44 years (median, 13 years) at ASCR, were treated. Three patients died of treatment-related toxicities within 21 days of ASCR; multiorgan system failure in two, and Aspergillus infection with venoocclusive disease in one. Seven of 23...
Optimal cutoff values for overweight: using body mass index to predict incidence of hypertension in 18- to 65-year-old Chinese adults.

Studies aimed at identifying body mass index (BMI) cutoffs representing increased diseased risk for Asians are typically based on cross sectional studies. This study determines an optimal BMI cutoff for overweight that represents elevated incidence of hypertension in Chinese adults with data from the China Health and Nutrition Survey 2000–2004 prospective cohort. Cumulative incidence was calculated by dividing new cases of hypertension over the study period by the total at-risk population, aged 18–65 years, in 2000. Sex-specific receiver operating characteristic (ROC) curves were used to assess the sensitivity and specificity of BMI as a predictor of hypertension incidence. Four-year cumulative incidences of hypertension (13% and 19% for women and men, respectively) were significantly (P < 0.005) related to the increase in BMI. The crude area under the curves (AUC) were 0.62 (95% CI: 0.59–0.65) and 0.62 (95% CI: 0.58–0.65) for men and women, respectively; the age-adjusted AUC were 0.68 (95% CI: 0.65–0.70) and 0.71 (95% CI: 0.68–0.74) for men and women, respectively. A BMI of 23.5 kg/m2 for women and 22.5 kg/m2 for men provided highest sensitivity and specificity (60%). The finding was consistent in different age groups. A BMI level of 25 kg/m2 provided lower sensitivities (36% for women and 29% for men) with higher specificities (80% for women and 85% for men). Our study supported the hypothesis that the BMI cutoff to define overweight should be lower in Chinese than in Western populations.
Blood cholesterol concentration: fingerstick plasma vs venous serum sampling

To assess whether venous and fingerstick blood samples yield similar cholesterol concentrations, we obtained both types of samples simultaneously in 108 volunteers participating in a cholesterol screening program. All samples were analyzed by the same enzymatic method in a standardized laboratory, and pairs of simultaneous samples were measured in the same laboratory run. Cholesterol concentrations in fingerstick-derived plasma were consistently higher than in the venous serum (P less than 0.0001), by a positive bias averaging 3.6%. Cholesterol values in fingerstick plasma also were higher than cholesterol results for venous serum placed in a capillary collection tube (average bias +2.4%). The positive bias of fingerstick plasma vs venous serum results appears to be at least partly due to specimen handling, although a true physiological difference between venous and fingerstick cholesterol concentrations is probably also involved. If a positive bias of this magnitude from fingerstick blood sampling is left unadjusted, substantial numbers of people will be labeled "at risk" and referred to physicians when their true values were actually within the acceptable range.
Triplet and ground state potential energy surfaces of 1,4-diphenyl-1,3-butadiene: theory and experiment

Relative energies of the ground state isomers of 1,4-diphenyl-1,3-butadiene (DPB) are determined from the temperature dependence of equilibrium isomer compositions obtained with the use of diphenyl diselenide as catalyst. Temperature and concentration effects on photostationary states and isomerization quantum yields with biacetyl or fluorenone as triplet sensitizers with or without the presence of O2, lead to significant modification of the proposed DPB triplet potential energy surface. Quantum yields for ct-DPB formation from tt-DPB increase with [tt-DPB] revealing a quantum chain process in the tt → ct direction, as had been observed for the ct → tt direction, and suggesting an energy minimum at the 3ct* geometry. They confirm the presence of planar and twisted isomeric triplets in equilibrium (K), with energy transfer from planar or quasi-planar geometries (quantum chain events from tt and ct triplets) and unimolecular decay (kd) from twisted geometries. Starting from cc-DPB, ϕcc→tt increases with increasing [cc-DPB] whereas ϕcc→ct is relatively insensitive to concentration changes. The concentration and temperature dependencies of the decay rate constants of DPB triplets in cyclohexane are consistent with the mechanism deduced from the photoisomerization quantum yields. The experimental ΔH between 3tt-DPB* and 3tp-DPB*, 2.7 kcal mol−1, is compared with the calculated energy difference [DFT with B3LYP/6-31+G(d,p) basis set]. Use of the calculated ΔS = 4.04 eu between the two triplets gives kd = (2.4–6.4) × 107 s−1, close to 1.70 × 107 s−1, the value for twisted stilbene triplet decay. Experimental and calculated relative energies of DPB isomers on the ground and triplet state surfaces agree and theory is relied upon to deduce structural characteristics of the equilibrated conformers in the DPB triplet state.
Interaction between oxidative stress and high-density lipoprotein cholesterol is associated with severity of coronary artery calcification in rheumatoid arthritis.

Objective To test the hypothesis that oxidative stress is increased in patients with rheumatoid arthritis (RA) due to increased inflammation and contributes to the pathogenesis of atherosclerosis. Methods The independent association between urinary F2-isoprostane excretion, a measure of oxidative stress, and RA was tested using multiple linear regression models in 169 patients with RA and 92 control subjects, frequency matched for age, race, and sex. The relationship between F2-isoprostane excretion and coronary calcium, a marker of atherosclerosis, was examined in multivariable proportional odds logistic regression models that also assessed the interactions between oxidative stress and low-density lipoprotein and high-density lipoprotein (HDL) cholesterol. Results F2-isoprostane excretion was significantly higher in patients with RA (median 2.75 [interquartile range (IQR) 1.60–4.06] ng/mg creatinine) than in control subjects (median 1.86 [IQR 1.25–2.62] ng/mg creatinine; adjusted P = 0.006). In patients with RA, F2-isoprostanes were positively correlated with body mass index (P 0.05 for all). In patients with RA, F2-isoprostanes significantly modified the effect of HDL cholesterol on coronary calcification (P = 0.02 for interaction) after adjustment for age, sex, and race. As F2-isoprostane levels increased, HDL lost its protective effect against coronary calcification. Conclusion Oxidative stress measured as F2-isoprostane excretion was higher in patients with RA than in control subjects. Among patients with RA, higher F2-isoprostane excretion and HDL cholesterol concentrations interacted significantly and were positively associated with the severity of coronary calcification.
Non‐invasive intravital fluorescent microscopy of the hamster gingiva

Several attempts have been made to visualize the gingival microcirculation of small animals. Most of these attempts have required surgical procedures without control of the local tissue environment. In our current study of the hamster gingiva, a tissue bath was designed to allow microcirculatory observations of the periodontium of the superior incisors without the need for invasive surgical procedures and with controlled pH and temperature of the bathing solution. Dextrans (m.w. = 70,000 and m.w. = 150,000), bovine serum albumin (mw = 66,210) or a globulin fraction (mw = greater than 450,000 less than 825,000) were conjugated to fluorescein isothiocyanate and injected into the animal. Fluorescent images, produced by epi-illumination, were analyzed for the light intensity of the interstitium. There was a large and rapid increase in light intensity (leakage of the macromolecules) near the venules while capillaries of the gingival margin developed interstitial fluorescence at a slower rate and with a lower maximal effect. Molecular weight, shape or charge of the macromolecular or age of the animal did not affect the results. This new preparation could be used to study the contribution of the microcirculation to gingivitis, the role of gingivitis in the development of periodontal disease, or the effects of drugs and hormones on the microcirculation of the gingiva.
Coupled-channels calculations of intermediate energy π+−13C inelastic scattering and charge exchange

Abstract Coupled-channels calculations have been carried out for pion inelastic scattering and charge exchange on 1p-shell nuclei at pion energies between 120 and 226 MeV. A momentum space technique is used, with the 1p-shell shell-model wavefunctions of Cohen and Kurath. Results are presented here for A =13. Channel-coupling effects are negligible in the strong 3 2 - and 5 2 - inelastic excitations of 13 C, but enhance the analog charge-exchange cross sections by 7 to 20%.
Dynamic void distribution in myoglobin and five mutants

Globular proteins contain cavities/voids that play specific roles in controlling protein function. Elongated cavities provide migration channels for the transport of ions and small molecules to the active center of a protein or enzyme. Using Monte Carlo and Molecular Dynamics on fully atomistic protein/water models, a new computational methodology is introduced that takes into account the protein's dynamic structure and maps all the cavities in and on the surface. To demonstrate its utility, the methodology is applied to study cavity structure in myoglobin and five of its mutants. Computed cavity and channel size distributions reveal significant differences relative to the wild type myoglobin. Computer visualization of the channels leading to the heme center indicates restricted ligand access for the mutants consistent with the existing interpretations. The new methodology provides a quantitative measure of cavity structure and distributions and can become a valuable tool for the structural characterization of proteins.
Multicomponent interferences in overloaded gradient elution chromatography

Abstract A theoretical study of multicomponent interferences has been performed by calculating band profiles in nonlinear overloaded gradient elution chromatography. The separation of binary and ternary mixtures has been modeled by means of a finite difference algorithm similar to the Craig mechanism, in the case when the adsorption behavior of the mixture components is accounted for by Langmuir competitive isotherms. The influence of the loading factor, the composition of the sample, and the gradient steepness have been investigated. In most cases, the profiles and the band interactions are qualitatively similar to those obtained under isocratic conditions. Although the profile fronts of the individual bands are very sharp, nearly vertical, the separation of closely eluted bands of ‘parallel’ or ‘divergent’ solutes cannot be improved significantly by gradient elution. Obviously, their retention time can be reduced considerably, which may improve the production rate although column regeneration must be carried out after each run, which increases the cycle-time. The elution profiles of impurities and trace components is usually very similar in gradient and in isocratic elution. This means that the recovery yield is not changed significantly, regardless of the gradient steepness. The most interesting results and the only one which is not observed under isocratic conditions, are obtained for the separation of ‘convergent’ solutes. In this case, the elution order of the components may change. This results in a kind of peak splitting, a fraction of the impurity eluting before the major component, the rest forming a flat profile spread along the profile of the major component. This phenomenon can be controlled or eliminated by adjusting the loading factor of the sample and the gradient steepness.
Electric field gradients in BaTiO3 and KNbO3

Abstract Electric field gradients have been calculated within the local density approximation for rhombohedral BaTiO3 and KNbO3 using an extended general potential linearized augmented planewave method.
A Role for TGFβ Signaling in the Pathogenesis of Psoriasis

Deregulation of transforming growth factor-β (TGFβ) signaling has been reported in human psoriasis. Our recent study using a keratin 5 promoter (K5.TGFβ1 wt ) showed that transgenic mice expressing wild-type TGFβ1 in the epidermis developed severe skin inflammation. Additional experimental data further support a direct role for TGFβ1 overexpression in skin inflammation. First, we temporally induced TGFβ1 expression in keratinocytes in our gene-switch TGFβ1 wt transgenic mice and found inflammation severity correlated with TGFβ1 wt transgene expression. Second, deletion of T cells in K5.TGFβ1 wt mice significantly delayed skin inflammation and associated epidermal hyperplasia/hyperkeratosis. Third, therapeutic approaches effective for human psoriasis, that is, Etanercept and Rosiglitazone, are effective in alleviating the symptoms observed in K5.TGFβ1 wt mice. Future studies will analyze specific mechanisms and identify key factors in TGFβ1-induced skin inflammation. Our mouse models will provide a useful tool for understanding the molecular mechanisms of inflammatory skin disorders in which TGFβ1 is overexpressed.
A New Faculty Orientation Program: Building a Core of New Faculty To Shape the Future of the College.

St. Louis Community College leadership recognized that a new large cohort of faculty hired to replace retiring instructors would shape the college over the next quarter century and beyond. The college challenged its staff development team to create a program that would integrate new faculty into the college and prepare them for the vital role they would play.
Fluidized-bed and fixed-bed reactor testing of methane chemical looping combustion with MgO-promoted hematite

Abstract In this study MgO-promoted Fe2O3 hematite oxygen carriers were synthesized from various Mg sources and evaluated for methane chemical looping combustion. Particles suitable for fluidized bed flow reactor studies were prepared in the lab. Cyclic CLC tests conducted in the fluidized bed with MgO promoted hematite showed better performance than that with hematite. Attrition resistance of laboratory prepared MgO promoted hematite was excellent. Reactivity and stability of the oxygen carrier materials were also tested in the thermogravimetric analyzer and bench-scale reactors. Scanning electron microscopy and energy-dispersive X-ray spectroscopy, and X-ray diffraction were used to study the morphology and elemental compositions present in the hematite and promoted hematite oxygen carriers prior to and following the multi-cycle chemical looping reaction. The incorporation of 5 wt% MgO led to an increased reaction rate and an increase in oxygen utilized as compared to the pure hematite oxygen carrier. Possible reasons for the promotion effect by MgO were evaluated. These studies reveal that the best performing oxygen carrier was the 5 wt% MgO/Fe2O3 which exhibited no observed degradation in the kinetics and conversion performance in the methane step over 15 reduction and oxidation cycles. The Mg promoted oxygen carrier also showed reduced coke formation as compared to the pure hematite carrier.
Motion Estimation in the 3-D Gabor Domain

Motion estimation methods can be broadly classified as being spatiotemporal or frequency domain in nature. The Gabor representation is an analysis framework providing localized frequency information. When applied to image sequences, the 3-D Gabor representation displays spatiotemporal/spatiotemporal-frequency (st/stf) information, enabling the application of robust frequency domain methods with adjustable spatiotemporal resolution. In this work, the 3-D Gabor representation is applied to motion analysis. We demonstrate that piecewise uniform translational motion can be estimated by using a uniform translation motion model in the st/stf domain. The resulting motion estimation method exhibits both good spatiotemporal resolution and substantial noise resistance compared to existing spatiotemporal methods. To form the basis of this model, we derive the signature of the translational motion in the 3-D Gabor domain. Finally, to obtain higher spatiotemporal resolution for more complex motions, a dense motion field estimation method is developed to find a motion estimate for every pixel in the sequence.
Hematopoietic recovery after unrelated umbilical cord-blood allogeneic transplantation in adults treated with in vivo stem cell factor (R-MetHuSCF) and filgrastim administration

Abstract Transplantation with unrelated umbilical cord blood (UCB) is marked by delayed hematologic recovery. This report summarizes two adults with chronic myelogeneous leukemia (CML), who received myeloablative conditioning followed by infusion of a non-expanded single UCB graft. These CML patients were enrolled in a clinical trial incorporating concomitant in vivo administration of stem cell factor (R-MetHuSCF) and filgrastim from day of UCB infusion until attained hematopoietic recovery. Each patient engrafted fully with donor UCB, with days to absolute neutrophil count (ANC) >500/μl being 13 and 29 days, respectively. Both patients remain in cytogenetic remission at 28 months follow-up. ‘In vivo UCB expansion’ with administration of concomitant R-MetHuSCF and filgrastim may facilitate prompt hematologic engraftment.
An experimental analysis of feedback to increase sexual arousal in a case of homo- and heterosexual impotence: A preliminary report

Abstract The effect of informational feedback concerning level of penile responding on subsequent sexual arousal was examined in a case of homo- and heterosexual impotence, using a single subject experimental design. Penile response to slides of nude males and nude females during separate measurement sessions without feedback was significantly increased during a phase where treatment sessions contained contingent feedback, decreased when feedback was administered non-contingently, and increased once again when contingent feedback was reinstated. The increase in penile responding was paralleled by achievement of ejaculation during masturbation, changes in masturbatory fantasy and reports of homo- and heterosexual arousal outside the laboratory.
Further intramolecular reactions of 1,2,4-triazines. Synthesis of furo[2,3-b]pyridines and dihydropyrano[2,3-b]pyridines

Abstract 3-(3-Butynyloxy)- and 3-(4-pentnyloxy)-1,2,4-triazines undergo facile intramolecular Diels-Alder reactions to yield 2,3-dihydrofuro(2,3- b )pyridines and dihydropyrano(2,3- b )pyridines respectively. The former are readily dehydrogenated with DDQ to furo(2,3- b )pyridines.
Immunoglobulin production: method for quantitatively detecting variant myeloma cells

Mouse myeloma cells in continuous culture were cloned in soft agar. The clones were assayed for their ability to synthesize heavy and light chains of gamma globulin by immunoprecipitation directly in the agar. A minor population secreting only light chains was identified. The two cell types were recloned and a low incidence of conversion of 7S to light-chain production was demonstrated. This technique can be used to isolate rare variants of cells secreting specific macromolecules.
Optimization of van der Waals Energy for Protein Side-Chain Placement and Design

Computational determination of optimal side-chain conformations in protein structures has been a long-standing and challenging problem. Solving this problem is important for many applications including homology modeling, protein docking, and for placing small molecule ligands on protein-binding sites. Programs available as of this writing are very fast and reasonably accurate, as measured by deviations of side-chain dihedral angles; however, often due to multiple atomic clashes, they produce structures with high positive energies. This is problematic in applications where the energy values are important, for example when placing small molecules in docking applications; the relatively small binding energy of the small molecule is drowned by the large energy due to atomic clashes that hampers finding the lowest energy state of the docked ligand. To address this we have developed an algorithm for generating a set of side-chain conformations that is dense enough that at least one of its members would have a root mean-square deviation of no more than R A from any possible side-chain conformation of the amino acid. We call such a set a side-chain cover set of order R for the amino acid. The size of the set is constrained by the energy of the interaction of the side chain to the backbone atoms. Then, side-chain cover sets are used to optimize the conformation of the side chains given the coordinates of the backbone of a protein. The method we use is based on a variety of dead-end elimination methods and the recently discovered dynamic programming algorithm for this problem. This was implemented in a computer program called Octopus where we use side-chain cover sets with very small values for R, such as 0.1 A, which ensures that for each amino-acid side chain the set contains a conformation with a root mean-square deviation of, at most, R from the optimal conformation. The side-chain dihedral-angle accuracy of the program is comparable to other implementations; however, it has the important advantage that the structures produced by the program have negative energies that are very close to the energies of the crystal structure for all tested proteins.
Dose indices: everybody wants a number

This paper discusses the merits and weaknesses of the standard terms that have been developed to quantify CT dose: CT dose indices (CTDI), dose length product (DLP) and effective dose. The difference between the measured CTDIvol and the CTDIvol displayed on the CT scanner illustrates a clinical dilemma. Displayed CTDIvol represents the radiation dose delivered to a plastic phantom, which is significantly different from the dose delivered to the patient, depending on the size of the patient. Although effective dose is simple to calculate for an individual patient, it was never intended for this purpose. The need for a simple, appropriate method to estimate pediatric patient doses led to the development of the size-specific dose estimate (SSDE), the newest CT dose index. Here I compare SSDE and its merits to the use of effective dose to estimate patient dose. The discussion concludes with a few sample calculations and basic clinical applications of SSDE to better quantify pediatric patient dose from CT scans.
Electromagnetic duality, Landau ghosts, superconductivity, QCD and all that

Abstract Electric-magnetic duality allows us to describe the dynamics of a medium via either an electric or a magnetic formulation. One immediate result is that a gluon with a 1 k 4 propagator must be propagating in a magnetic superconducting medium. Another consequence is that there are no QCD Van der Waals forces. We predict the existence of short range Yukawa forces whose range is directly related to an important confinement parameter; the QCD London penetration depth. We prove the following and its dual; magnetic charges anti-screen electric potentials. Based on this result we present two conjectures. (1) The vertex of a charged particle and a “dual” photon carries an extra factor of i. (2) Magnetic monopoles exorcise the Landau ghost.
On the tradeoff between resilience and degree overload in dynamic P2P graphs

Prior work has shown that resilience of random P2P graphs under dynamic node failure can be improved by age-biased neighbor selection that delivers outbound edges to more reliable users with higher probability. However, making the bias too aggressive may cause the group of nodes that receive connections to become small in comparison to graph size. As they become overloaded, these peers are forced to reject future connection requests, which leads to potentially unbounded join delays and high traffic overhead. To investigate these issues, we propose several analytical models for understanding the interplay between resilience and degree. We formulate a Pareto-optimal objective for this tradeoff, introduce new metrics of resilience and degree, analyze them under Pareto lifetimes, and discover that traditional techniques can be highly suboptimal in this setting. We then show evidence that optimization can be solved by a family of step-functions, which connect outgoing edges to uniformly random users whose age exceeds some threshold.
Collective processes of an ensemble of spin- 1/2 particles

When the dynamics of a spin ensemble are expressible solely in terms of symmetric processes and collective spin operators, the symmetric collective states of the ensemble are preserved. These many-body states, which are invariant under particle relabeling, can be efficiently simulated since they span a subspace whose dimension is linear in the number of spins. However, many open system dynamics break this symmetry, most notably when ensemble members undergo identical, but local, decoherence. In this paper, we extend the definition of symmetric collective states of an ensemble of spin-$1∕2$ particles in order to efficiently describe these more general collective processes. The corresponding collective states span a subspace that grows quadratically with the number of spins. We also derive explicit formulas for expressing arbitrary, identical, local decoherence in terms of these states. We then investigate the open system dynamics of experimentally relevant nonclassical collective atomic states, including superposition and spin squeezed states, subject to various symmetric but local decoherence models.
Linear dependence in basis‐set calculations for extended systems

The problem of linear dependence in basis-set calculations for extended systems is discussed. We show that the problem is intrinsic in three-dimensionally extended systems, but is not as serious in systems with extension in fewer dimensions. The possibility of choosing suitable basis sets that avoid linear dependence is discussed. It is shown that for systems extended in three dimensions in which the orbitals near the Fermi-level are well described by plane waves a mixed atomicorbital/plane-wave (AO–PW) basis set with tight orbitals to describe the cores avoids the problem in the most efficient way. Numerical experiments with 1s Slater-type orbitals and plane waves on a simple cubic lattice are presented for illustration. © 1992 John Wiley & Sons, Inc.
Molecular determinants of polyubiquitin linkage selection by an HECT ubiquitin ligase

Ubiquitin (Ub)-protein ligases (E3s) frequently modify their substrates with multiple Ub molecules in the form of a polyubiquitin (poly-Ub) chain. Although structurally distinct poly-Ub chains (linked through different Ub lysine (Lys) residues) can confer different fates on target proteins, little is known about how E3s select the Lys residue to be used in chain synthesis. Here, we used a combination of mutagenesis, biochemistry, and mass spectrometry to map determinants of linkage choice in chain assembly catalyzed by KIAA10, an HECT (Homologous to E6AP C-Terminus) domain E3 that synthesizes K29- and K48-linked chains. Focusing on the Ub molecule that contributes the Lys residue for chain formation, we found that specific surface residues adjacent to K48 and K29 are critical for the usage of the respective Lys residues in chain synthesis. This direct mechanism of linkage choice bears similarities to the mechanism of substrate site selection in sumoylation catalyzed by Ubc9, but is distinct from the mechanism of chain linkage selection used by the Mms2/Ubc13 (Ub E2 variant (UEV)/E2) complex.
Unlocking the magic of Maxwell's equations

The direct solution of Maxwell's equations for high-frequency design at the device level is discussed, focusing on the use of finite-element methods. Some of the computational difficulties encountered are examined, and the use of Delaunay triangulation for mesh generation, which mitigates some of the problems, is described. The application of finite-element analysis to magnetics is discussed. >
HIV-1 Preintegration Complexes Preferentially Integrate into Longer Target DNA Molecules in Solution as Detected by a Sensitive, Polymerase Chain Reaction-based Integration Assay

After entering a cell and undergoing reverse transcription, the retroviral genome is contained in a preintegration complex (PIC) that mediates its integration into host cell DNA. PICs have been shown to prefer torsionally strained DNA, but the effect of target DNA length has not been previously examined. In this report, concatemerization of a repeating 105-base pair unit was used to vary target DNA length independently from basic DNA sequence, while maintaining both PICs and target DNAs in solution. Integration junctions were quantified by real-time fluorescence-monitored polymerase chain reaction amplification using primers in the viral long terminal repeat and the target DNA. Unreacted target DNA severely inhibited the post-reaction polymerase chain reaction detection step, requiring its removal using λ exonuclease digestion. Integration into a 32-unit concatemer of target DNA was markedly more efficient than integration into a monomeric unit, indicating that longer target DNA was preferred. This substrate was used to construct a simple, robust, and adaptable assay that can serve as a method for studying the host cell factors that enhance PIC integration, and as a drug discovery platform for integration inhibitors active against PICs.
Ionisation and Temperature

THE discourse by Prof. J. J. Thomson, published in NATURE of March 22 (vol. lxxiii., p. 495), was of importance from several points of view. The explanation of the method of ionisation which he suggests was of especial interest to myself, and I should be pleased if I might be allowed to raise one query concerning it.
Inclusion conjunctivitis in the newborn infant

Inclusion conjunctivitis occurred in 5 infants between the third and twenty-sixth days of life. A thick yellow discharge was present in all 5 infants, moderate-to-marked lid edema in 4, and diffuse conjunctival injection in 3. No follicles, corneal lesions, or preauricular adenopathy were observed. The diagnosis was made in each instance by finding characteristic intracytoplasmic inclusions in epithelial cells obtained by scraping the lower palpebral conjunctiva and stained by the Giemsa technique. Marked improvement occurred in each infant by the third day of local tetracycline therapy. The causative organism is a member of the Bedsonia group which is indistinguishable from the agent of trachoma and is spread by venereal contact. Diagnosis is made only by laboratory methods.
SU-E-T-21: Repair of DNA Damage from Ionizing Radiation in the Range of Doses Experienced in CT Studies

Purpose: To quantify the kinetics of the cellular response to low, CT‐relevant doses of ionizing radiation (IR) in U87MG human glioblastoma multiforme cancer cells in vitro. Method and Materials:U87MG cells were irradiated with 0Gy (controls), 20mGy (in typical CT range), or 2Gy (exceeding CT dose range) using an X‐ray cabinet irradiator at 150kVp. The cellular kinetics of DNA damage and response were quantified by flow cytometric quantitation of &#61543;H2AX foci at two time points (1hr and 6hrs post‐IR); using flow cytometry allows a much higher throughput than conventional methods. An auto‐fluorescence control was performed for each sample. Collected flow cytometry data, corrected for debris and dead cells using side and forward scatter gating, were analyzed with CellQuest Pro Software.Fluorescence histograms were generated for each sample and the respective auto‐fluorescence histogram was subtracted from each. The percentage of gated cells staining positive for &#61543;H2AX (beyond an a priori threshold based on the IgG negative control) was determined. Results: In cells exposed to 2Gy, &#61543;H2AX substantially increased within 1h and returned to control levels 6h post‐irradiation. In contrast, although cells exposed to 20mGy showed a measureable increase in &#61543;H2AX formation within 1h, there was no significant decrease 6h later. Conclusion: Our results suggest DNA damage induced by low, CT‐relevant doses is repaired at a slower rate than damage induced by higher doses. This altered kinetic response could have marked biological effects for current radio‐diagnostic procedures. Our study, therefore, underscores the importance of understanding the different repair mechanisms at different dose regions in order to accurately assess risk estimates and biological dose. Future work will investigate longer observation times to assess DNA repair in more detail in the current cell model as well as in normal lymphocyte cell lines. This work is partially supported by a SIEMENS Corporation research grant.
Hitting in Amateur Ice Hockey: Not Worth the Risk

The "big hit" is glorified in professional ice hockey. But body checking is unnecessary for the quality of the game and demonstrably dangerous for most amateur players at the youth, high school, and college levels.
My Father’s Ghost A Story of Encounter and Transcendence

This autoethnography is about my personal search for my father, who was an early presence in my life, but who gradually became a palpable absence. In many ways, I have been searching for my father all my life, and somehow hoping to rekindle a relationship that I have experienced mostly as something I lost early. As my search progressed across a span of more than fifty years, I found my father in the one place I least expected. In this article, I begin to write my father in a new light, one that offers insights into his legacy for me, and for my sons. In the end, I hope to write our lives in a way that captures just a bit of the spirit of my spirited father.
Monitoring Reactions of Nitric Oxide with Peptides and Proteins by Electrospray Ionization-Mass Spectrometry

Recent studies have demonstrated the biological importance of the interaction of nitric oxide (NO) with proteins. Protein-associated targets of NO include heme, Cys, and Tyr. Electrospray ionization-mass spectrometry was used to monitor the results of exposure of model peptides and an enzyme to NO under different conditions and thus addressed aspects of NO-protein interactions. The molecular mass of a decapeptide containing a single Cys residue increased by 29 Da upon treatment with NO under aerobic and acidic conditions, consistent with the substitution of one NO moiety. The mass of reduced somatostatin, a peptide containing two Cys residues, increased by 58 Da, consistent with the substitution of two NO moieties. These substitutions were prevented by pretreatment of the peptides with Nethylmaleimide. The strength of the nitrosothiol bond was examined by varying the amount of energy applied to the peptide ions and indicated a labile species. Cys residues were very rapidly nitrosated, while other reactions were observed to occur at much slower rates. These include the further oxidation of nitrosothiol to sulfonic acid and nitration of Tyr. Peptides treated with NO at physiological pH were observed to undergo dimerization as well as nitrosation. These studies were extended to the enzyme p21ras, whose activity has been postulated to be modulated by nitrosothiol formation, and revealed the formation of a single nitrosothiol on p21ras upon NO treatment. These data suggest that electrospray ionization-mass spectrometry allows for quantitation and characterization of nitrosothiol bonds in peptides and proteins.
Ab initio molecular orbital study of the tautomerism of 4‐hydroxy‐2‐pyridinone

Ab initio calculations were performed on 2,4-pyridinediol, 4-hydroxy-2-pyridinone, and 2hydroxy-4-pyridinone at the HF/3-21G level with full geometry optimization. Two conformations of the hydroxyl group were considered for each tautomer. Corrections for polarization functions, electron correlation, and zero point energy were made by comparison with previous calculations on 2- and 4-pyridinone tautomerism which included these contributions. The most stable structure is 4-hydroxy-2-pyridinone, in agreement with experiment. Relative to 4-hydroxy-2-pyridinone, the energies of the other tautomers are estimated to be 1.9 kcal/mol for 2,4-pyridinediol and 8.9 kcal/mol for 2-hydroxy-4-pyridinone. These are in accord with the experimental values 0.3 ± 1.9 and 10.6 ± 1.9 kcal/mol, respectively, deduced from equilibration studies of the tautomeric methyl derivatives.
A combined catalyst and sorbent for enhancing hydrogen production from coal or biomass

Future large-scale production of H{sub 2} for use as a clean fuel will likely depend upon gasifying coal or biomass followed by steam reforming the resulting gas mixture and separating the CO{sub 2} byproduct. The process of steam reforming and CO{sub 2} separation can be greatly simplified by utilizing a new material that combines a reforming catalyst with a sorbent for CO{sub 2}. Such a material was prepared in the form of small pellets with cores made of calcium and magnesium oxides and shells made largely of alumina impregnated with a nickel catalyst. Subsequent laboratory performance tests of the material showed that CO, CH{sub 4}, and toluene, which are representative products of gasification, were largely converted to H{sub 2} by reacting the material with steam in the presence of the catalyst/sorbent, so that CO{sub 2} was absorbed as it was produced. The sorbent was easily regenerated by raising its temperature, which made it possible to reuse the catalyst/sorbent repeatedly. 14 refs., 4 figs., 1 tab.
The impact of a stem‐boring insect on the tissues, physiology and reproduction of Russian thistle

A stem-boring moth, Coleophora parthenica was introduced into California from Pakistan, in 1973, in a biological control attempt against the weed, Russian thistle (Salsola australis). A population of Russian thistle plants growing near Coalinga, California, which were infested and damaged by varying numbers of C. parthenica larvae, was studied to better understand the moth's impact. The xylem sap pressures were measured during the period of seed set. No significant correlations were obtained between the measured levels of water stress and the amounts of C. parthenica infestations and damage in these plants, except late in the season, but these are not considered to be important. Translocation of carbon-14 was studied during seed set. The levels of translocation and C. parthenica infestations and damage in the plants were not correlated. Measured levels of various reproductive indices did not correlate significantly with the levels of larval infestation and damage. Histological and x-ray examinations of the damaged stems showed that once C. parthenica larvae enter the stems of Russian thistle they feed only in the pith and do not damage the critical xylem and phloem. This explains why the plant's translocation, water balance, and reproduction were unaffected by C. parthenica. Coleophora parthenica appears to have very limited value as a biological control agent of Russian thistle, except perhaps as part of a complex of natural enemies attacking the plant. Resume Effets d'une mineuse des tiges sur les tissus, la physiologie et la production de Salsola australis Coleophera parthenica Meyrick (Lep., Coleophoridae), mineuse de tiges, a ete introduite en 1973 du Pakistan en Californie, pour lutter contre Salsola australis. Pour mieux apprehender l'effet de C. parthenica, une population de S. australis attaquee par la mineuse a ete suivie pres de Coalinga (Californie). La pression de seve du xyleme a ete mesuree pendant la periode de production des graines. Aucune correlation n'est apparue entre les niveaux de stress hydrique et les taux d'infestation et les degâts de C. parthenica, sauf en fin de saison; mais ils n'ont pas ete alors estimes importants. Le transfert de C14 a ete etudie pendant la periode de production de graines; aucune correlation n'est apparue avec les infestations et les degâts de C. parthenica. Les differents indices de la reproduction n'etaient pas significativement lies aux niveaux d'infestation et de degâts larvaires. Les examens histologiques et par rayons X des tiges attaquees ont montre qu'apres la penetration des chenilles de C. parthenica dans les tiges de S. australis, celles-ci ne s'alimentent que dans la moelle sans atteindre gravement le xyleme et le phloeme. Ceci explique pourquoi, les transferts dans la plante, la circulation de l'eau et la reproduction, ne sont pas modifies par C. parthenica; cet insecte semble n'offrir que tres peu d'interet pour la lutte biologique contre S. australis, sauf peut-etre comme element du complexe des ennemis naturels de cette plante.
The Attention Skills and Academic Performance of Aggressive/Rejected and Low Aggressive/Popular Children

Research Findings: Aggressive/rejected children are at risk for continuing conduct and school problems. Some limited research indicates that these children have attention problems. Previous research has linked attention problems with academic performance. The current study investigated group differences in attention skills and the role of these skills in children's academic performance. Kindergarten and 1st-grade children (n = 54, 52% female) were identified as either aggressive/rejected or low aggressive/popular by peer sociometric interviews. Attention was assessed with a novel computer task, the Children's Space Game, as well as parent and teacher report. Teachers reported on children's academic performance. Aggressive/rejected children had lower adult-reported attention skills and academic performance than low aggressive/popular children. Aggressive/rejected children also had lower skills on the computer task. Support was found for an additive model of the influence of children's status and attention ...
Hypercoagulability following blunt solid abdominal organ injury: when to initiate anticoagulation.

Background The optimal time to initiate venous thromboembolism pharmacoprophylaxis after blunt abdominal solid organ injury is unknown.
Interferon inhibits the release of plasminogen activator from SV3T3 cells.

INTERFERON, as well as inducing an antiviral state, can modify certain other cell characteristics. For example, it has been shown to inhibit cell proliferation1–4 and release of C-type virus5,6, and to enhance the expression of H–2 antigens7,8 and the amount of glycoprotein on the cell surface9. These effects might be explained by decreased release of cell-surface components into the medium. Similarly, the expression of a glycoprotein on the cell surface has been related to the growth state of cells10, which can be explained in part by differential release11,12. We have followed up this suggestion by examining the effect of interferon on the release of plasminogen activator (PA) by a line of simian virus 40 transformed Swiss 3T3 (SV3T3) cells. Our results, reported here, indicate that interferon inhibits the release of PA by SV3T3 cells.
Peptic erosion of the cystic artery with massive duodenal hemorrhage: therapeutic embolization

Two patients with massive upper gastrointestinal hemorrhage due to duodenal ulceration underwent visceral angiography. In both cases there was extravasation of contrast from the cystic artery directly into the duodenal lumen. Selective transcatheter embolization of the right hepatic artery was performed in each patient, and in both cases, hemorrhage was controlled. Transcatheter embolization is introduced as an effective therapeutic measure in this unusual entity.
Robust output feedback control of uncertain switched Euler-Lagrange systems

Output feedback (OFB) controllers for switched systems have been typically developed for linear systems. Of the OFB controllers that have been designed for switched nonlinear systems, at least partial knowledge of the system parameters is required, or the system results in local stability. In this paper, an OFB, time-dependent, switched controller is developed for an Euler-Lagrange system with parametric uncertainty and exogenous disturbances. The time-dependent switching signal is designed using an average dwell-time scheme based on multiple Lyapunov functions such that the switched system achieves semi-global uniformly ultimately bounded (UUB) tracking with arbitrary switching sequences.