cssi/SciSciGPT-SciSciNet huggingface dataset:
Mouse Folylpoly-γ-glutamate Synthetase Isoforms Respond Differently to Feedback Inhibition by Folylpolyglutamate Cofactors†

Folylpoly-gamma-glutamate synthetase (FPGS) is the enzyme responsible for metabolic trapping of reduced folate cofactors in cells for use in nucleotide and amino acid biosynthesis. There are two isoforms of FPGS expressed in mouse tissues, one is expressed in differentiated tissue, principally liver and kidney, and the other in all rapidly proliferating cell types. The present study sought the functional difference that would explain the evolution of two mouse FPGS species. Recombinant cytosolic mouse isozymes were compared with respect to steady state kinetics, chain length of polyglutamate derivatives formed, and end-product inhibition by the major reduced folylpentaglutamate cofactors. Both isoforms were equally effective in catalyzing the addition of a mole of glutamic acid to reduced folate monoglutamate substrates. Each isoform was also capable of forming long chain polyglutamate derivatives of the model folate, 5,10-dideazatetrahydrofolate. In contrast, the FPGS isoform derived from rapidly proliferating tissue was much more sensitive to inhibition by (6R)-5,10-CH(2)-H(4)PteGlu(5) and (6S)-H(4)PteGlu(5) than the isoform expressed in differentiated tissues, as demonstrated by 13- and 6-fold lower inhibition constants (K(i)), respectively. Interestingly, each isozyme was equally sensitive to inhibition by (6R)-10-CHO-H(4)PteGlu(5). We drew the conclusion that the decreased sensitivity of the FPGS expressed in mouse liver and kidney to feedback inhibition by 5,10-CH(2)-H(4)PteGlu(5-6) and H(4)PteGlu(5-6) may have evolved to permit accumulation of a larger folate cofactor pool than that found within rapidly proliferating tissue.
The two-stage nuclear reaction N14(t, n)O16*(p)N15

Abstract A remarkably clear example of a two-stage nuclear reaction has been observed. Broad, steep-sided proton groups, observed during the bombardment of nitrogen by tritons, have been ascribed to the process N 14 (t, n)O 16* (p)N 15 . It is notable that this reaction appears to proceed by way of particular sharp states in O 16 at an excitation of about 15 MeV.
Do health care professionals find the use of age‐based rationing to reduce health care costs ethical?

Purpose – As a result of the aging of American society, health care costs have been and will continue to rise, to the extent that they are not sustainable. Obviously, this trend will continue in spite of the 2010 health care reform. As a result of this uncontrollable problem, writers such as Daniel Callahan have proposed age‐based rationing of health care while utilizing the utilitarian notions of ethics and justice. However, other writers, utilizing more egalitarian notions of justice, have opposed this. This suggests an ethical dilemma, which has to be debated in the future. The author believes professors teaching health care related courses will be instrumental in this debate, explaining why she decided to seek the opinion of a sample of 18 professors regarding this issue. The purpose of this paper is to report on the results of this research.Design/methodology/approach – Qualitative methodology, specially grounded theory, was used in this study that sought to explore the views of 18 full‐time professo...
Nonlinear Dynamics of Electrically Actuated Carbon Nanotube Resonators

This work presents an investigation of the nonlinear dynamics of carbon nanotubes (CNTs) when actuated by a dc load superimposed to an ac harmonic load. Cantilevered and clamped-clamped CNTs are studied. The carbon nanotube is described by an Euler-Bernoulli beam model that accounts for the geometric nonlinearity and the nonlinear electrostatic force. A reduced-order model based on the Galerkin method is developed and utilized to simulate the static and dynamic responses of the carbon nanotube. The free-vibration problem is solved using both the reduced-order model and by solving directly the coupled in-plane and out-of-plane boundary-value problems governing the motion of the nanotube. Comparison of the results generated by these two methods to published data of a more complicated molecular dynamics model shows good agreement. Dynamic analysis is conducted to explore the nonlinear oscillation of the carbon nanotube near its fundamental natural frequency (primary-resonance) and near one-half, twice, and three times its natural frequency (secondary-resonances). The nonlinear analysis is carried out using a shooting technique to capture periodic orbits combined with the Floquet theory to analyze their stability. The nonlinear resonance frequency of the CNTs is calculated as a function of the ac load. Subharmonic-resonances are found to be activated over a wide range of frequencies, which is a unique property of CNTs. The results show that these resonances can lead to complex nonlinear dynamics phenomena, such as hysteresis, dynamic pull-in, hardening and softening behaviors, and frequency bands with an inevitable escape from a potential well.
Surface photovoltage analysis of iron contamination in silicon processing and the relation to gate oxide integrity

ABSTRACT Surface photovoltage (SPY), a contactiess optical technique for measuring minority carrierlifetime, is used to quantify the relationship between silicon iron contamination level and thin gateoxide integrity. Iron concentration levels in the range of 1x101° cm3 to 5x1013 cm3 are evaluatedfor oxide thicknesses of 8 to 20 nm. Ramp voltage electrical breakdown and time dependantdielectric breakdown measurement on the iron contaminated gate oxide capacitors are reported.Distinct iron contamination threshold limits based on defect density and gate oxide integrityanalysis for each oxide thickness are provided. The SPY iron detection technique is also used toevaluate cleaning efficiencies and metallic cross contamination effects during thermal processing contamination. Iron-suicide precipitation kinetics are investigated by the lifetime analysis procedure.Keywords: surface photovoltage, carrier lifetime, gate oxide integrity, oxide breakdown, contamination in silicon, iron contaminationINTRODUCTION
Reproductive health in SLE

Oral contraceptives containing oestrogens and hormone replacement therapy are generally not prescribed for women with systemic lupus erythematosus (SLE). The concern regarding oestrogens is based on the greater incidence of SLE in women, abnormalities of oestrogen metabolism, murine models of lupus, several anecdotes of patients having disease flares while receiving hormones, and one retrospective study in patients with pre-existing renal disease. For healthy women and those with SLE, there are clinical settings in which exogenous oestrogens provide benefit. For pre-menopausal women, these include provision of safe and effective birth control, protection against bone loss, and the consideration of oral contraceptives to preserve fertility in patients taking cyclophosphamide. For post-menopausal women, these include treatment of hot flushes and vaginal dryness, prevention of osteoporosis and, more controversial, prevention of atherosclerosis. Other exogenous hormones (clomiphene citrate, gonadotropins, gonadotropin-releasing hormones) may be used to elevate levels of endogenous oestrogen and stimulate ovulation in patients with diminished fertility. This chapter focuses on three broad categories: birth control, assisted reproduction and hormone replacement.
Role of BDNF in the taste system

Neurotrophins are a family of proteins that regulate neural survival, development, function and plasticity in the central and the peripheral nervous system. There are four neurotrophins: NGF, BDNF, NT-3 and NT-4. Among them, BDNF is mostly studied in the taste system due to its high expression. Recent studies have shown BDNF play an important role in the developmental and mature taste system, by regulating survival of taste cells and geniculate ganglion neurons, and maintaining and guiding taste nerve innervations. These studies imply BDNF has great potentialities for therapeutic usage to enhance sensory regeneration following nerve injury, with aging, and in some neurodegenerative diseases.
UThPb age of Apollo 12 rock 12013

Abstract A UThPb isotopic study of three chips from lunar rock 12013 indicates that parental material of the intrusion breccia formed quite early in the moon's history, possibly 3.9 to 4.3 by ago. The UThPb characteristics of the rock are distinctly different from those of other Apollo 12 igneous rocks and suggest a different origin.
Myeloid cells functioning in tumor vascularization as a novel therapeutic target

Angiogenesis, the sprouting of new blood vessels to sustain growth, is an important new target in solid tumor therapy. Initial studies focused on the role of the tumor cell in promoting angiogenesis; yet more recent work has demonstrated that host cells in the tumor microenvironment also play a critical role in tumor vascularization. Additionally, vasculogenesis in which new blood vessels develop from vascular progenitor cells also contributes to tumor growth. Recent studies propose a central role for cells of the myeloid lineage in triggering vessel growth by releasing angiogenic factors and perhaps by incorporating directly into nascent blood vessels. We will review studies that support a critical role for myeloid cells in neovascularization, with a focus on cells that express various monocytic/dendritic cell markers, including vascular leukocytes (VLCs), Tie2+ monocytes, and vascular endothelial growth factor receptor 2 (VEGFR2)+ monocytes, among others. The evidence that these myeloid cells represent bona fide therapeutic targets for solid tumors will be reviewed. Finally, we will address some controversies and challenges in the field with a focus on future directions.
Analysis of the Mi-2 autoantigen of dermatomyositis.

Objective. To determine the biochemical structure and antigenic components of Mi-2 autoantigen, the target of autoantibodies in 15–20% of dermatomyositis patients. Methods. Immunoprecipitation from 35S-labeled HeLa cell extract, immunoblotting, and purification from bovine thymus by immunoaffinity chromatography. Results. All 46 sera that had anti–Mi-2 autoantibodies demonstrated by immunodiffusion immunoprecipitated a major protein of ∼240 kd. Additional proteins of 200, 150, 72, 65, 63, 50, and 34 kd appeared to be part of the antigen. Fractions of purified bovine Mi-2 with antigenic activity showed high molecular weight bands comparable with immunoprecipitated HeLa Mi-2. Twenty-four of 47 anti–Mi-2 positive sera reacted with the 240-kd protein by immunoblot against anti–Mi-2 immunoprecipitates. Conclusion. Mi-2 antigen consists of multiple proteins, of which the 240-kd protein appears to be the major reactive component.
Statistical recombinant mapping in extended high-risk Utah pedigrees narrows the 8q24 prostate cancer locus to 2.0 Mb.

Background Chromosome 8q24 is a region of compelling interest for prostate cancer (PRCA). Linkage, association, and admixture analysis initially indicated the region. Subsequently, several variants at 8q24 have been found to independently associate with PRCA. One compelling hypothesis is allelic heterogeneity, whereby multiple variants affect the regulation of the same gene. In addition to potential allelic heterogeneity, 8q24 exhibits strong linkage disequilibrium over vast distances and is prone to chromosomal aberrations. Methods Allelic heterogeneity and complex chromosomal structure are factors that hinder progress towards gene identification using association. Linkage techniques, however, are robust to allelic heterogeneity and therefore can contribute important localization information. We have used a linkage-based localization technique to perform recombinant mapping in eight high-risk Utah pedigrees. Results Using pedigree-based recombinant mapping we identify a 5.7 Mb region at 8q24.21–22, between markers D8S1774 and D8S557. Considering our region with the localization previously presented, we can delimit the 8q24 PRCA locus to a 2.0 Mb consensus interval from 127.5 to 129.5 Mb. Conclusion We have used a linkage-based, recombinant mapping technique in extended high-risk Utah pedigrees to successfully narrow the 8q24 PRCA locus. The region we present halves the 95% credible interval previously described using admixture analysis and contains only three annotated genes: FAM84B, MYC, and TMEM75. It should be noted that LD stretches far beyond the interval we describe, and hence this region adds important information about where to focus future efforts to isolate the causal variants and underlying gene, whether by linkage or association techniques. Prostate 67: 1456–1464, 2007. © 2007 Wiley-Liss, Inc.
Vibrational energy transfer efficiency in a three‐channel thermal unimolecular system. Temperature dependence

Thermal isomerization in the three‐channel cyclopropane‐1t1‐2,2d2 system was studied at 823 and 973 K in the presence of Kr and CO2 bath gases. It was found that CO2 is more efficient in energy transfer from the hot cyclopropane than Kr, which is more efficient than He. For the stepladder model of energy transfer, the average energy removed per collision from energized cyclopropane‐1t1‐2,2d2 by a bath gas 〈ΔE〉 for Kr is 780±90 cm−1 at 823 K and 520±70 cm−1 at 933 K; while for CO2 it is 1220±90 cm−1 at 823 K and 800±70 cm−1 at 973 K. The relative collision efficiency of both bath gases βω also declines with temperature rise. For Kr, βω is 0.17 at 823 K and 0.07 at 973 K; for CO2, βω is 0.40 at 823 K and 0.17 at 973 K. Comparison is made with earlier results. A T−γ(γ∼5.5) temperature dependence fits the existing data for He/cyclopropane sytems and is in accord with the computational deductions of Tardy and Rabinovitch (Ref. 17). For stronger colliders, e.g., Kr and CO2, the temperature dependence of βω ...
A Shared- and distributed-memory parallel general sparse direct solver

An important recent development in the area of solution of general sparse systems of linear equations has been the introduction of new algorithms that allow complete decoupling of symbolic and numerical phases of sparse Gaussian elimination with partial pivoting. This enables efficient solution of a series of sparse systems with the same nonzero pattern but different coefficient values, which is a fairly common situation in practical applications. This paper reports on a shared- and distributed-memory parallel general sparse solver based on these new symbolic and unsymmetric-pattern multifrontal algorithms.
A Marching-on-in-Degree Solution of Volume Integral Equations for Transient Electromagnetic Scattering by Bi-Isotropic Objects

Abstract A time-domain volume integral equation solved by the marching-on-in-degree scheme is presented for the analysis of transient electromagnetic scattering from three-dimensional inhomogeneous bi-isotropic objects. Based on the volume equivalence principle, the volume-based coupled integral equations for electric and magnetic flux densities are formulated. The transient variations of the electric and magnetic flux densities are expanded in terms of weighted Laguerre polynomials. With the use of the Galerkin spatial and temporal testing procedure, the proposed algorithm overcomes the late-time instability problem that often occurs in the marching-on-in-time approach. Numerical results are presented to illustrate the accuracy and versatility of the proposed algorithm.
Integrated Optical Sensor Platform based on Evanescent Field Coupling for Biochemical Sensor Applications

A photodetector integrated waveguide platform for diverse types of evanescent-wave sensor applications has been developed. Using this platform, surface plasmon resonance (SPR) detection has been demonstrated. The waveguide was made of SU-8 polymer as a guiding layer and siliconoxynitride (SiOxNy) as a cladding layer. The metal-semiconductor-metal (MSM) type photodetector coupled to the waveguide provides flexibility in design and fabrication compared to a pin (p-intrinsic-n) photodetector. We present a universal sensor architecture that can be used for evanescent-field based interrogation with (a) controllable refractive index and (b) integrated opto-electric signal conversion.
Identification of dansyl dipeptides in the Dansyl--Edman peptide degradation.

Abstract The manual dansyl-Edman 1 degradation procedure is one of the most convenient and widely used techniques for the sequencing of peptides up to about 15 residues in length (1,2). A frequently encountered complication in this procedure is the resistance of certain peptide bonds to acid hydrolysis. If the amino terminal peptide bond of the dansylated peptide is especially resistant, the dansyl dipeptide is frequently in higher yield than the corresponding dansyl amino acid. The resistant dansyl dipeptide is often composed of two hydrophobic amino acid residues. The resistance of such peptide bonds to acid hydrolysis is well understood (3). Other resistant bonds have, however, been noted in practice, e.g., those involving a hydrophobic and a prolyl residue. This phenomenon can lead to difficulty in interpretation of the thin-layer chromatogram and to subsequent incorrect identification of amino acid residues. Extending the hydrolysis time to 24 hr still leaves especially resistant dipeptides as the major product while significantly reducing the yield of other dansylated residues, notably dansyl proline, serine, and threonine. We report here the chromatographic behavior of 18 dansyl dipeptides on polyamide thin-layers using the solvent systems commonly employed in the dansyl-Edman procedure (2). All of these dipeptides have been encountered in practice, and the extent of hydrolysis in 6 n HCl at 110°C is usually less than 20%.
American Toussaints: Symbol, Subversion, and the Black Atlantic Tradition in the American Civil War

During the American Civil War, Toussaint Louverture was for African Americans the touchstone of a transatlantic identity, which joined their violent struggle for freedom and equality to a black revolutionary tradition that was deeply rooted in the eighteenth-century Atlantic world. White abolitionists reinforced the construction of this identification, for when they saw armed and uniformed black men, they likewise imagined American Toussaints, committed, disciplined, and talented slave soldiers who were eager to both die and kill for freedom. The men and women who seized upon the revolutionary symbols of Toussaint and the Haitian Revolution at this critical moment in the history of the American republic advanced a subversive ideology that undermined the white supremacist ideas that buttressed both the institution of slavery as well as the republic itself.
Linearization using efficient complex polynomial evaluations

Wideband wireless communications base stations could benefit from efficient arithmetic algorithms for cost effective digital baseband computations. Power amplifiers are ubiquitous in such systems and exhibit nonlinearity, causing spectral growth and in-band distortion, which in turn increase error rates. A digital predistorter compensates for nonlinear effects in the power amplifier by transforming the signal with a complex-valued polynomial (linearization). This requires a fast and efficient evaluation scheme for complex polynomials. In this paper, digit-serial techniques for evaluating linearization transformations are presented. Our contributions include algorithmic techniques for increasing throughput and experimental results for FPGAs.
From Mumbai to Shanghai, With a Side Trip to Hong Kong: China, India, and the Future of Progressive Taxation in an Asian-Led World

Progressive taxation has historically been discussed primarily in the context of developed, Western nations. This article considers its application in two developing, nonwestern economies, emphasizing differences in political, economic, and (especially) cultural contexts and their effect on the progressivity equation. In India these differences include long-standing attitudes, such as the the Hindu tradition's historic ambivalence about utilitarian arguments, and shorter-term institutional arrangements, such as the division of power within India's federal system and the tax exemption for agricultural income. In China they include the legacy of marxism as well as a more long-standing tendency to resolve legal and policy issues based on notions of communal rather than individual welfare. Both countries have limited administrative resources and (by western standards) a relatively small middle class, so that the income tax remains a relatively small if growing source of national revenues. The article considers the impact of these factors, and concludes by asking if a similar "tax life cycle" will apply to both countries or whether political and cultural differences will result in divergent tax patterns. The article further evaluates the progressivity problem as a case study in comparative taxation and the need to develop a more sophisticated methodology for dealing with institutional, attitudinal, and other cultural differences.
The ratio of flexural strength to uniaxial tensile strength in bulk epoxy resin polymeric materials

Abstract The flexural behavior of epoxies was investigated by performing mechanical tests and applying statistical Weibull theory and analytical methods to the results. The effects of loading systems and environmental conditions were also considered. Three kinds of epoxies were studied: Epon E863, PRI 2002, and PR520. In total, 53 three-point-bending (3PB) Epon E863 samples and 26 3PB PR520 were tested immediately after curing, together with 26 four-point-bending (4PB) PRI2002 samples stored at 60°C and 90% Rh for 48 weeks. The Weibull parameters were estimated using both linear regression and the moments method. The statistical character of the Weibull model leads to uncertainty in the evaluated parameters, even for a large number of experiments. This study analyzed the ratio of flexural strength to tensile strength in bulk epoxy resin polymers. An analytical method previously developed by the authors to study the relationship between uniaxial tension/compression stress-strain curves and flexural load-deflection response was used to obtain the ratio. The results show that the Weibull model overpredicted the aforementioned ratio in different load arrangements.
Decentralized Bargain: A Two-Tier Market for Efficient and Flexible Dynamic Spectrum Access

Market mechanisms have been exploited as important means for spectrum acquisition and access in cognitive radio networks. In this paper, we propose a two-tier market for decentralized dynamic spectrum access. In the proposed Tier-1 market, spectrum is traded from a primary user (PU) to secondary users (SUs) in a relatively large time scale to reduce signaling overhead. Then, driven by dynamic traffic demands, SUs set up the Tier-2 market to redistribute channels among themselves in a small time scale. More specifically, we use a Nash bargain game to model the spectrum acquisition of SUs in the Tier-1 market and derive the equilibrium prices. We then employ a strategic bargain game to study the spectrum redistribution in the Tier-2 market, where SUs can exchange channels with low overhead through random matching, bilateral bargain, and the predetermined market equilibrium price. We investigate how various factors, such as the availability of channels and bargain partners, matching strategies, and traffic dynamics, affect the market relationships. This work provides new understanding on the spectrum market and valuable guidelines to primary and secondary network operators.
Time Resolved Collapse of a Folding Protein Observed with Small Angle X-Ray Scattering

High-intensity, "pink" beam from an undulator was used in conjunction with microfabricated rapid-fluid mixing devices to monitor the early events in protein folding with time resolved small angle x-ray scattering. This Letter describes recent work on the protein bovine beta-lactoglobulin where collapse from an expanded to a compact set of states was directly observed on the millisecond time scale. The role of chain collapse, one of the initial stages of protein folding, is not currently understood. The characterization of transient, compact states is vital in assessing the validity of theories and models of the folding process.
Reported survival with severe mixed acidosis and hyperlactemia after toluene poisoning

Lactic acidosis is a recognized complication of the inhalant abuse such as toluene, especially in patients with renal insufficiency. We report a case of severe metabolic acidosis and hyperlactemia due to toluene sniffing. The favorable outcome, despite extremely poor clinical symptoms, signs, laboratory and radiological findings, was unexpected. Specific aspects of the clinical course are addressed. Toluene sniffing should be considered in evaluating sever metabolic acidosis. Favorable outcome could be achieved with early diagnosis and proper interventions.
Fast spherical search algorithm

This paper describes an algorithm to search a number of spherical points and find the points that are within a given distance to a given point. The described algorithm is not optimal, but is easy to implement. Basically, it utilizes a number of spherical coverings to build the data structure. Results of an implementation are presented.
Interactive data analytics: the new frontier

Data analytics often involves data exploration, where a data set is repeatedly analyzed to understand root causes, find patterns, or extract insights. Such analysis is frequently bottlenecked by the underlying data processing system, as analysts wait for their queries to complete against a complex multilayered software stack. In this talk, I'll describe some exploratory analytics applications we've build in the MIT database group over the past few years, and will then describe some of the challenges and opportunities that arise when building more efficient data exploration systems that will allow these applications to become truly interactive, even when processing billions of data points.
Organic synthesis in pursuit of immunology: large-scale synthesis of peracetylated GM2 glycosylamino acid for preparation of a multiantigenic prostate cancer vaccine

We describe herein the stereocontrolled, large-scale synthesis of peracetylated GM2 glycosylamino acid. Key features of the synthesis include a newly modified [1 + 3] coupling reaction and an olefin cross-metathesis-hydrogenation sequence. The GM2 glycosylamino acid is now ready for incorporation into a hexavalent prostate cancer vaccine construct.
Pilot testing of a decision support tool for patients with abdominal aortic aneurysms.

Objective Patients with abdominal aortic aneurysms (AAAs) who are surgical candidates have as many as three options: open surgery, endovascular surgery, or no surgery. As with all treatment decisions, informed patient preferences are critical. Decision support tools have the potential to better inform patients about the risks and benefits associated with each treatment option and to empower patients to participate meaningfully in the decision-making process. The objective of this study was to develop and pilot test a decision support tool for patients with AAAs. Methods We developed a personalized, interactive, computer-based decision support tool reflecting the most current outcomes data and input from surgeons and patients. We piloted the tool with AAA repair candidates who used the tool prior to meeting with their surgeon. Patients were recruited from a university-based vascular surgery clinic and affiliated VA hospital clinic. To determine feasibility and acceptability, the following outcomes were measured: (1) percent of patients who agreed to participate, (2) length of time required to use the tool, (3) the amount of assistance required to use the tool, and (4) patients' opinions on the acceptability of the tool. To assess effectiveness of the tool, we measured change in knowledge and decisional conflict pre- and post-tool using the paired t -test. Results One hundred percent of patients who were approached (n = 12) agreed to participate in the study. The tool was administered in a median time of 35 minutes (range, 25-45 minutes), and all patients were able to navigate the program with minor technical assistance. Mean knowledge scores increased from 56% to 90% ( P = .005), and decisional conflict scores decreased from 29% to 8% ( P = .04). Overall, patients reported that the program content was balanced across treatment options, presented information clearly and concisely, helped them to organize their thoughts about the decision, and prepared them to talk to their surgeon about what mattered most to them. Conclusions Preliminary evidence suggests that use of an evidence-based AAA decision support tool is feasible and acceptable to patients, increases knowledge, and decreases decisional conflict. Widespread use of such a tool might improve the content and quality of informed consent for this difficult treatment decision.
Determination of intermolecular energy transfer by time resolved CARS measurements

Abstract Energy transfer in methyl isocyanide following i.r. multiphoton excitation has been examined with a CARS probe. Results show that CARS is an effective technique both for measuring the fraction of molecules receiving energy from the laser and for monitoring intermolecular energy transfer following laser irradiation. In addition, the Raman transition at 2169 cm −1 shows a vibrational progression due to hot bands of the ν 8 bend. Since the ν 8 , bend is the only low energy mode of the molecule, it is an effective vibrational “thermometer”. Utilizing this thermometer, results show that the vibrational state distribution does not fit a Boltzmann distribution for 7 μs following i.r. multiphoton excitation.
Interpatient Variability: Genetic Predisposition and Other Genetic Factors

Polymorphisms and other genetic factors related to enzymes metabolizing drugs and xenobiotic chemicals are well known. This article focuses on selected molecular mechanisms and introduces some of the clinical implications arising from genetically determined interpatient variability or expression in some of these enzymes. Selected are the polymorphic enzymes of cytochromes P-450 (CYP) as examples of phase I enzymes and methyl transferases, n-acetyl transferases, and glutathione-s-transferases as examples of phase II enzymes. The polymorphism surrounding arylhydrocarbon hydroxylase induction is briefly described. Phase I enzymatic reactions are predominantly oxidative, whereas phase II reactions often couple with the byproducts of phase I. Overall, in poor metabolizers, whether phase I or phase II, there is limited metabolism in most patients unless another major metabolic pathway involving other enzymes exists. Drug metabolism also depends on whether the parent compound is a prodrug that forms an active metabolite, and poor metabolizers under this condition will form only trace amounts of an active compound. Therefore, the clinical significance of genetic polymorphisms and other genetic factors may be related to substrate, metabolite, or the major elimination pathway.
Regulation of methylthioribose kinase by methionine in Klebsiella pneumoniae.

Summary: 5-Methylthioribose (MTR) kinase catalyses a key step in the recycling of methionine from 5′-methylthioadenosine, a co-product of polyamine biosynthesis, in Klebsiella pneumoniae. In defined medium lacking methionine, K. pneumoniae exhibits abundant MTR kinase activity. When the bacterium is transferred to a medium containing 10 mM-methionine, the specific activity of MTR kinase decreases in a fashion consistent with repression of new enzyme synthesis and dilution of existing enzyme by cell division. The specific activity of methionine synthase decreases to a similar degree under the same conditions. In Escherichia coli and Salmonella typhimurium, the gene for methionine synthase is co-ordinately controlled as part of the methionine regulon. Taken together, our results indicate that a methionine regulon may function in K. pneumoniae and that expression of MTR kinase may be under its control.
Quaternary structure of glutamate decarboxylase of Escherichia coli as revealed by electron microscopy.

Electron microscopy of negatively stained and metal-shadowed specimens of glutamate decarboxylase showed that the undissociated molecule of the enzyme is a hexamer with dihedral symmetry, and that the subunits are packed in an approximate octahedral arrangement. The maximum diameter and the “height” of the molecule are approximately 13.5 nm and 6 to 7 nm, respectively.
Curcumin Modulates the Radiosensitivity of Colorectal Cancer Cells by Suppressing Constitutive and Inducible NF-κB Activity

Purpose Radiation therapy is an integral part of the preoperative treatment of rectal cancers. However, only a minority of patients achieve a complete pathologic response to therapy because of resistance of these tumors to radiation therapy. This resistance may be mediated by constitutively active pro-survival signaling pathways or by inducible/acquired mechanisms in response to radiation therapy. Simultaneous inhibition of these pathways can sensitize these tumors to radiation therapy. Methods and Materials Human colorectal cancer cells were exposed to clinically relevant doses of gamma rays, and the mechanism of their radioresistance was investigated. We characterized the transcription factor nuclear factor-κB (NF-κB) activation as a mechanism of inducible radioresistance in colorectal cancer and used curcumin, the active ingredient in the yellow spice turmeric, to overcome this resistance. Results Curcumin inhibited the proliferation and the post-irradiation clonogenic survival of multiple colorectal cancer cell lines. Radiation stimulated NF-κB activity in a dose- and time-dependent manner, whereas curcumin suppressed this radiation-induced NF-κB activation via inhibition of radiation-induced phosphorylation and degradation of inhibitor of κB alpha, inhibition of inhibitor of κB kinase activity, and inhibition of Akt phosphorylation. Curcumin also suppressed NF-κB–regulated gene products (Bcl-2, Bcl-x L , inhibitor of apoptosis protein-2, cyclooxygenase-2, and cyclin D1). Conclusions Our results suggest that transient inducible NF-κB activation provides a prosurvival response to radiation that may account for development of radioresistance. Curcumin blocks this signaling pathway and potentiates the antitumor effects of radiation therapy.
NULL TEST OF QUANTUM MECHANICS USING TWO-PHOTON DOWN-CONVERSION

A null test of quantum mechanics is proposed. It is based on an arrangement in which a source sends two signals to two detectors. At each detector one of two different quantities can be measured. If the source satisfies three conditions, all of which can be verified experimentally, then, according to quantum mechanics, a particular outcome is forbidden. This result follows only from the way in which quantum mechanics constructs probabilities, and does not involve any dynamics. Looking for this outcome is a test of quantum mechanics. It is shown how this test can be realized using two-photon down-conversion.
Differential inhibition of the MLR by iron: association with HLA phenotype.

The effect of iron on the MLR was examined by pretreating peripheral blood mononuclear cells from 77 unrelated Caucasians with five concentrations of Ferric-citrate (10.0 mM, 1.0 mM, 0.1 mM, 0.01 mM and 0.005 mM). After incubation with the metal, the cells were washed and cultured in a one-way MLR with a pool of stimulator cells. Cell viability remained unchanged (greater than 90 percent) during the 6-day culture period. Citrate per se had no effect on either the responder or the stimulator population. Iron treatment influenced the MLR in the following ways: (1) a variable degree of inhibition was observed which related to the dose of Ferric-citrate used and to HLA phenotype, (2) the responder but not the stimulator cells were affected, (3) no statistically significant differences were seen between female and male donor cells and (4) the mean percent response of cells from HLA-A2 donors were significantly (0.005<P<0.01) less susceptible to iron exposure than those from non-HLA-A2 individuals.
Comment on Steven C. Bourassa and William G. Grigsby's “income tax concessions for owner‐occupied housing”

Abstract The article by Bourassa and Grigsby is another in a series of studies evaluating alternatives to homeownership incentives in the Internal Revenue Code. A consensus has emerged that the current structure of tax incentives may not be an optimal way to enhance homeownership, especially among low‐ to moderate‐income or minority households. After evaluating the efficiency and equity of the four existing tax incentives, they recommend that the mortgage interest and property tax deductions be eliminated. I agree with many of the points they raise. However, I argue that they need to incorporate the social benefits of homeownership into their analysis, to further consider allocative efficiency and distributional equity, and to recognize political acceptability as an important criterion for evaluation. I also believe that the administrative costs of compliance would not be especially burdensome, that housing shortages would not be a problem, and that additional homeownership tax concessions may be feasible.
Total Synthesis of (±)-Tazettine

The total synthesis of (±)-tazettine (1) has been achieved in 16 steps from commercially available piperonyl alcohol in 11% overall yield. The crucial quaternary center was assembled by a novel [4+1] cycloaddition between dimethoxycarbene and β-aryl vinyl isocyanate (4). Samarium diiodide conditions were employed to reduce the enamide unsaturation in the [2]benzopyrano[3,4-c]hydroindole intermediate 19 to compound 20 exhibiting a cis-AB ring fusion.
Velocity of DNA in gels during field inversion

The velocity and alignment of T4 and \ensuremath{\lambda} DNA have been measured during field-inversion gel electrophoresis (FIGE) at field strengths E between 6 and 14 V/cm. Immediately after E changed sign, the velocity exhibited an oscillatory behavior before reaching a steady value. The times at which these oscillations occurred were shorter for \ensuremath{\lambda} DNA (48.5 kilo-base-pairs) and longer for smaller E. However, the distance each DNA had traveled, when scaled by its contour length L, was about 0.1 for the first velocity peak and 0.15--0.3 for the undershoot for both molecular weights and all values of E studied, provided that E was on for at least 12 s prior to the field inversion. If the field was on for only a short time before inversion, the first sharp peak in velocity was progressively reduced in magnitude and duration. The alignment function f=(3〈${\mathrm{cos}}^{2}$\ensuremath{\theta}〉-1)/2, where \ensuremath{\theta} is the angle between the helix axis and E, was measured for the same DNA's, field strengths, and pulse times. The alignment was at all times parallel to E but decreased sharply immediately after field inversion to a minimum, followed by an overshoot and then a plateau. The time after field inversion at which the minimum in f occurred was approximately the same as that of the velocity maximum. The anticorrelation between the velocity and f, as well as the invariance of x/L for the velocity overshoot, support the idea, first suggested by computer simulations, that DNA undergoing gel electrophoresis spends much time hooked over gel fibers in ssU-shaped chain configurations. The measured velocity curves of T4 DNA were integrated to compute the net displacement after a series of positive and negative field inversions. The average velocity computed from this displacement showed a pronounced ``antiresonance'' or minimum at the same pulse period as observed in practical FIGE separations.
Does cross-clamping the arch increase the risk of descending thoracic and thoracoabdominal aneurysm repair?

Background Descending thoracic and thoracoabdominal aortic aneurysms may arise in the distal aortic arch. Repair of these aneurysms has been associated with increased morbidity and operative mortality. Complex surgical and endovascular techniques have reduced the risks for this cohort. We examined outcomes utilizing an approach based on simple cross-clamping of the arch. Methods From July 1997 to January 2004, 272 consecutive patients had aneurysm repair through the left chest. Twenty-nine requiring profound hypothermic circulatory arrest (PHCA) were excluded. Two hundred and forty-three were divided into two groups: group I (n = 60) had distal arch involvement and required cross-clamping proximal to the left subclavian artery. Group II (n = 183) were cross-clamped distal to the subclavian. Adjuncts for neurologic and renal protection were utilized as needed. Results In-hospital mortality for all 243 patients was 3.7%. There was no difference in mortality between groups (I, 3.3% vs II, 3.8%). Group I patients also had similar rates of paraplegia (I, 0% vs II, 2.2%), stroke (I, 1.2% vs II ,1.1%), and renal failure (I, 1.7% vs II, 5.5%). Group I patients had significantly more recurrent nerve palsies (I, 33% vs II, 4.9%) although this did not translate into a higher incidence of respiratory failure. Conclusions Repair of thoracic aneurysms arising in the distal arch can be repaired with a technique based on simple cross-clamping without an increase in mortality or major neurologic injury. Recurrent nerve palsy is much more common with this approach but is well-tolerated without increasing the need for tracheostomy.
Simulation of photovoltaic performance in a thin film, hybrid heterojunction incorporating a nanoscale semiconductor spectral sensitizer

The impact of CdTe nanoscale semiconductor spectral sensitizers on the energy conversion efficiency of a poly-(hexylthiophene) (P3HT)-ZnO thin film (TF) photovoltaic (PV) cell was examined utilizing a one-dimensional computational model (Solar Cell Capacitance Simulator) (SCAPS). Output characteristics (quantum efficiency spectra, current-voltage characteristics) of TF PV cells containing the CdTe phase embedded within the n-type (ZnO) region of the junction were investigated with the modeling parameters derived from previous experimental studies of the component materials. The study focused on the influence of the spatial position of the CdTe region, relative to the P3HT-ZnO heterojunction, on the spectral characteristics of the energy conversion efficiency of the device. The contribution of this sensitizer phase to energy conversion was confirmed and the magnitude of the effect was found to increase as the semiconductor nanophase region was moved to within 20 nm of the heterojunction.
Magnetic moment and atomic volume in supersaturated Fe–Cu solid solutions: Ab initiocalculations compared with experiments

The properties of nonequilibrium face-centered-cubic (fcc) and body-centered-cubic (bcc) Fe–Cu alloys were studied using the first-principles full-potential linearized augmented plane wave method within the generalized gradient approximation. The ab initio calculation results are compared quantitatively with the magnetic moment and atomic volume observed for mechanically alloyed FexCu100–x (x = 0 to 100) supersaturated bcc and fcc solid solutions. The calculations show that Cu alloying leads to a small enhancement of the magnetic moment of bcc Fe. The fcc Fe moment, on the other hand, experiences a more pronounced increase into a high-spin state upon alloying with Cu. It reaches approximately the same value as that in the bcc alloys for all Cu concentrations where fcc solutions are obtained in experiments, corroborating previous ab initio calculations using different methods. The magnetic moment increases are accompanied by an atomic volume expansion. Both the calculated moment and volume behavior are in good agreement with those measured for fcc and bcc Fe–Cu solutions. The magnetovolume expansion upon magnetic interaction between the alloyed Fe and Cu, rather than the positive heat of mixing, constitutes the primary reason for the atomic volume increase observed.
Scheduling multi-purpose batch plants with junction constraints

SUMMARY There is an increasing trend in the chemical process industry to operate flexible batch plants because of their capability to manufacture multiple products simultaneously by sharing the same process resources. In this paper, the scheduling of multi-purpose batch chemical plants with junction (header) constraints is considered. A mixed-integer non-linear model for the scheduling of multi-purpose batch chemical plants is formulated that considers the connection between equipment sets, transfer times, variable batch sizes, alternative process plans, and batch merging. Because of the computational time complexity of the batch scheduling problem, a heuristic scheduling algorithm that minimizes the total tardiness is developed lo solve the model.
Effects of interface traps on the transconductance and drain current of InP MISFET's

The drain current, transconductance, and output resistance of an InP MISFET are shown to depend strongly on the frequency and amplitude of an AC signal applied to the gate. This dependence exists even though the familiar long-term current drift effect is negligible. To explain this phenomenon a new nonequilibrium interface-trap model is proposed. >
Market liquidity and volume around earnings announcements

Abstract This paper suggests that earnings announcements provide information that allows certain traders to make judgements about a firm's performance that are superior to the judgements of other traders. As a result, there may be more information asymmetry at the time of an announcement than in nonannouncement periods. More information asymmetry implies that bid–ask spreads increase, suggesting that market liquidity decreases at the time of an earnings announcement. Furthermore, informed opinions resulting from public disclosure may lead to an increase in trading volume, despite the reduction in liquidity that accompanies announcements.
Observations on the kinetics of action of polyspermine-ribonuclease on poly(A)·Poly(U)

Starting from the observation that double-stranded ribonucleic acids are hydrolyzed more rapidly by bovine pancreatic ribonuclease that has been cross-linked to polyspermine, we have made an initial examination of the kinetics of the process. The addition of eight residues of the polyamine serves to strengthen the binding to poly(A).poly(U) 100-fold (Km changes from 2.7 . 10(-4) to 2.7 . 10(-6) M in total U) and to increase V for hydrolysis of the susceptible poly(U) strand from 2.5 to 16.2 delta A250 . min-1 per mg enzyme. There is evidence for inhibition by the RNAase-resistant poly(A) tracts in the substrate; free poly(A) shows a Ki of about 8 . 10(-6) M in total A.
Evidence for novel 30,000-50,000Mr cofactor in the activation of muscle.

Abstract A new approach is described for reconstituting a fully desensitized skeletal muscle fiber to restore its contractility. These studies revealed a novel regulatory cofactor, 30–50,000Mr by filtration (26–55kDa by SDS PAGE). It was shown to be critical for the Ca2+-activation in the physiological milieu. The cofactor was present in skeletal and cardiac muscles as well as in brain, but not in kidney and liver. The cofactor may be a second Ca2+ switch in a dual-regulation scheme for vertebrate muscle, or could provide an essential link in the cross-bridge cycle beyond activation.