cssi/SciSciGPT-SciSciNet huggingface dataset:
Effect of macro and micro voids on elastic properties of polymer composites

An analytical model is presented to estimate elastic properties of polymer composites with voids of various sizes and locations. The model is based upon a multi level homogenization procedure incorporated with a micromechanics model. Different scenarios of voids in fiber reinforced composites are considered and their effects on deterioration of elastic properties ofthe composites are analyzed. Comparisons with finite element numerical results and available experimental results for unidirectional fiber reinforced composites are also provided as an evidence of the applicability of the model.
Dual Catalytic Decarboxylative Allylations of α‐Amino Acids and Their Divergent Mechanisms

This is the peer reviewed version of the following article: Lang, S. B., O'Nele, K. M., Douglas, J. T. and Tunge, J. A. (2015), Dual Catalytic Decarboxylative Allylations of α-Amino Acids and Their Divergent Mechanisms. Chem. Eur. J., 21: 18589–18593. doi:10.1002/chem.201503644, which has been published in final form at http://doi.org/10.1002/chem.201503644. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
Performance of two different quantum annealing correction codes

Quantum annealing is a promising approach for solving optimization problems, but like all other quantum information processing methods, it requires error correction to ensure scalability. In this work, we experimentally compare two quantum annealing correction (QAC) codes in the setting of antiferromagnetic chains, using two different quantum annealing processors. The lower-temperature processor gives rise to higher success probabilities. The two codes differ in a number of interesting and important ways, but both require four physical qubits per encoded qubit. We find significant performance differences, which we explain in terms of the effective energy boost provided by the respective redundantly encoded logical operators of the two codes. The code with the higher energy boost results in improved performance, at the expense of a lower-degree encoded graph. Therefore, we find that there exists an important trade-off between encoded connectivity and performance for quantum annealing correction codes.
Factors Determining Callbacks to Job Applications by the Unemployed: An Audit Study

We use an audit study approach to investigate how unemployment duration, age, and holding a low- level interim job while applying for a better job affect the likelihood that experienced college-educated females applying for an administrative support job receive a callback from potential employers. First, the results show no relationship between callback rates and unemployment duration. Second, workers age fifty and older are significantly less likely to receive a callback. Third, taking an interim job significantly reduces the likelihood of receiving a callback. Finally, employers who have higher callback rates respond less to observable differences across workers in determining whom to call back.
Magnetic field line lengths inside interplanetary magnetic flux ropes

We report on the detailed and systematic study of field line twist and length distributions within magnetic flux ropes embedded in interplanetary coronal mass ejections (ICMEs). The Grad-Shafranov reconstruction method is utilized together with a constant-twist nonlinear force-free (Gold-Hoyle) flux rope model to reveal the close relation between the field line twist and length in cylindrical flux ropes, based on in situ Wind spacecraft measurements. We show that the field line twist distributions within interplanetary flux ropes are inconsistent with the Lundquist model. In particular, we utilize the unique measurements of magnetic field line lengths within selected ICME events as provided by Kahler et al. (2011a) based on energetic electron burst observations at 1 AU and the associated type III radio emissions detected by the Wind spacecraft. These direct measurements are compared with our model calculations to help assess the flux rope interpretation of the embedded magnetic structures. By using the different flux rope models, we show that the in situ direct measurements of field line lengths are consistent with a flux rope structure with spiral field lines of constant and low twist, largely different from that of the Lundquist model, especially for relatively large-scale flux ropes.
The observed neutron star mass distribution as a probe of the supernova explosion mechanism

The observed distribution of neutron star (NS) masses reflects the physics of core-collapse supernova explosions and the structure of the massive stars that produce them at the end of their evolution. We present a Bayesian analysis that directly compares the NS mass distribution observed in double NS systems to theoretical models of NS formation. First, we find that models with standard binary mass ratio distributions are strongly preferred over independently picking the masses from the initial mass function, although the strength of the inference depends on whether current assumptions for identifying the remnants of the primary and secondary stars are correct. Secondly, NS formation models with no mass fallback are favoured because they reduce the dispersion in NS masses. The double NS system masses thus directly point to the mass coordinate where the supernova explosion was initiated, making them an excellent probe of the supernova explosion mechanism. If we assume no fallback and simply vary the mass coordinate separating the remnant and the supernova ejecta, we find that for solar metallicity stars the explosion most likely develops at the edge of the iron core at a specific entropy of S/NA≈ 2.8 kB. The primary limitations of our study are the poor knowledge of the supernova explosion mechanism and the lack of broad range of supernova model explosions of Large Magellanic Cloud to solar metallicity.
Short, Efficient Syntheses of Pyrrole α-Amides

Abstract We report an inexpensive method for producing a diverse array of pyrrole amides on a large scale and in good yield. The synthetic sequence allows for the preparation of a number of pyrrole amide derivatives in excellent to moderate yields from commercially available compounds. The diketene adduct, in the presence of an amine nucleophile, provides an excellent method for acetoacetylation. For diversity and versatility, a second method utilizing Meldrum's acid was successfully employed for the preparation of additional acetoacetamide derivatives. Using the Knorr pyrrole synthesis, pyrrole amides were readily prepared from the oxime of the acetoacetamides.
Electrochemical and spectroscopic methods of characterizing lead corrosion films

Abstract One of the major causes of failure in lead-acid batteries is the corrosion of the lead current collector at the lead dioxide electrode. The corrosion films which form are complex because changing voltage and concentration gradients across the film favor different reaction products as corrosion progresses. Although excellent studies have been accomplished using mainly electrochemical techniques, X-ray diffraction, electron microscopy, and metallography, development of additional knowledge has been frustrated by the following limitations of these methods: (1) poor resolution of the signals from the many lead compounds which form in the corrosion film, (2) poor spatial resolution of the multiple corrosion product layers which are evident in micrographs of film cross sections, and (3) the inability to analyze the corrosion products in situ to determine the time sequence of species formation. Recently several new approaches to studying lead corrosion films have overcome some of these limitations. These techniques, which include laser Raman spectroscopy, photocurrent and photoacoustic spectroscopy and solid state electrochemistry, are reviewed. Significant results from their application are summarized.
A Varying Parameters Approach to Constructing House Price Indexes

Conventional housing price index models assume interperiodparameter stability and typically employ either repeat sales or hedonic methodologies. This paper introduces a method of index construction that combines multiple sales observations with single sale transactions while permitting characteristics prices from hedonic regressions to vary over time. A test for interperiod parameter stability is provided. Each period's data are arranged by location and repeat sales are matched by rows. This construction allows greater use of sample information and acknowledges the unique contribution of repeat sales to the estimation process. It also produces intertemporal error correlations that can be beneficially exploited by the seemingly unrelated regressions (SUH) technique. The paper also demonstrates a significance test for error correlation and discusses the treatment of unequal numbers of observations among index periods.
Allylpalladium Umpolung in the Three-Component Coupling Synthesis of Homoallylic Amines

Homoallylic amines and α-amino esters were prepared via a Pd(II)-catalyzed coupling of boronic acids and 1,2-nonadiene with ethyl iminoacetate or aliphatic, aromatic, and heteroaromatic imines. The allylpalladium umpolung was induced by a Pd(OAc)2 catalyst with commercial phosphine ligands.
Alterations in normal fatty acid composition in a temperature-sensitive mutant of a thermophilic bacillus.

A temperature-sensitive mutant of a thermophilic bacillus was isolated which was unable to maintain membrane integrity at high temperature. The mutant appeared to lose cytoplasmic contents, as indicated by a decrease in turbidity and cell refractivity, when shifted from a permissive (52° C) to a restrictive (65° C) temperature. Cell number remained fairly constant, however. At the approximate onset of the decline in turbidity, viability decreased and net synthesis of ribonucleic acid, deoxyribonucleic acid, and protein ceased. Both chloramphenicol and sucrose were effective in retarding the decline in turbidity at 65° C. An abnormal fatty acid composition at high temperature suggested that the lesion in the mutant involved lipid synthesis. The proportion of fatty acids with a high melting point (> 55° C) increased in the parent from 42% at 42° C to 69% at 65° C. Similar changes were not made by the mutant. An abnormal phospholipid composition was also observed in the mutant at 42° C and 52° C. However, at 58° C, the maximum growth temperature of the mutant, the proportion of major phospholipids (phosphatidylglycerol, phosphatidylethanolamine, and cardiolipin) was similar to the parent strain. The mutant's apparent loss of membrane stability at high temperature and its inability to regulate fatty acid and phospholipid composition in a normal manner suggested that (i) the temperature-sensitivity of the mutant may be a result of a defect in normal lipid metabolism at high temperature and (ii) the normal changes in fatty acid composition observed at increased growth temperatures may be an essential feature of thermophily.
Exoplanet detection with simultaneous spectral differential imaging: effects of out-of-pupil-plane optical aberrations

Imaging faint companions (exoplanets and brown dwarfs) around nearby stars is currently limited by speckle noise. To efficiently attenuate this noise, a technique called simultaneous spectral differential imaging (SSDI) can be used. This technique consists of acquiring simultaneously images of the field of view in several adjacent narrow bands and in combining these images to suppress speckles. Simulations predict that SSDI can achieve, with the acquisition of three wavelengths, speckle noise attenuation of several thousands. These simulations are usually performed using the Fraunhofer approximation, i.e. considering that all aberrations are located in the pupil plane. We have performed wavefront propagation simulations to evaluate how out-of-pupil-plane aberrations affect SSDI speckle noise attenuation performance. The Talbot formalism is used to give a physical insight of the problem; results are confirmed using a proper wavefront propagation algorithm. We will show that near-focal-plane aberrations can significantly reduce SSDI speckle noise attenuation performance at several {lambda}/D separation. It is also shown that the Talbot effect correctly predicts the PSF chromaticity. Both differential atmospheric refraction effects and the use of a coronagraph will be discussed.
Coherent Electromagnetic Heavy Ion Reactions: (1) Exact Treatment of Pair Production and Ionization; (2) Mutual Coulomb Dissociation

Some recent theoretical results on coherent electromagnetic processes in ultrarelativistic heavy ion reactions are surveyed. In ultrarelativistic heavy ion collisions, Coulomb induced cross sections are huge, much larger than geometric. For the RHIC case of 100 GeV x 100 GeV colliding gold ions the predicted cross section for bound-electron positron pairs is about 110 barns. The corresponding cross section for continuum electron-positron pairs has recently been recalculated to be 34,000 barns, consistent with the result of the classic formula of Landau and Lifshitz. The cross section for Coulomb dissociation of the nucleus is about 95 barns, and the cross section for ionization of a single electron on one of the ions is about 100,000 barns.
Principled Enforcement of Penal Codes

* Associate Professor, University of Utah College of Law. This article is dedicated to my teacher and friend, Bob Weisberg, who introduced me to the charms and warts of the Model Penal Code. 1. Herbert Wechsler, The Challenge of a Model Penal Code, 65 Harv. L. Rev. 1097, 1102 (1952). 2. Frank J. Remington, The Future of the Substantive Criminal Law Codification Movement—Theoretical and Practical Concerns, 19 Rutgers L.J. 867, 893 (1988). 3. Louis B. Schwartz, Morals Offenses and the Model Penal Code, 63 Colum. L. Rev. 669, 671 (1963). 4. This is not the first such claim, nor will it be the last. See Wayne R. LaFave & Austin W. Scott, Jr., Criminal Law 3 (2d ed. 1986) (“In the realm of substantive criminal law, by far the most significant development has been the completion of the American Law Institute’s Model Penal Code . . . .”); Sanford H. Kadish, The Model Penal Code’s Historical Antecedents, 19 Rutgers L.J. 521, 538
Design standard issues for ITER in-vessel components

Abstract Design loadings and potential mechanical damage in ITER in-vessel components are enumerated. Design by analysis requirements for ITER blanket and divertor are discussed in the light of the decreasing ductility of the structural material as a function of the neutron fluence. The applicability and limitations of the ASME Boilers and Pressure Vessels Code, Section III to ITER components are discussed. The design rules from fission reactor core components are reviewed for potential application to ITER.
Interannual variability of Mars' south polar cap

Abstract Telescopic data on the twentieth-century regressions of Mars' south polar cap have been reexamined for evidence of interannual variability. Several regressions, particularly that of 1956, are found to differ significantly from the mean. The possibility of correlations with major dust storms is explored.
Enantiospecific formal total syntheses of (-)-salicylihalamides A and B from D-glucose and L-rhamnose.

Two formal chiral pool syntheses of the (−)-salicylihalamides A and B were achieved from commercially available 1,2,5,6-diacetone-d-glucose and l-rhamnose.
Do Graduate Student Teacher Training Courses Affect Placement Rates

We investigate whether the existence of a required graduate course on “Teaching in Political Science” is related to overall job placement rates reported by graduate political science programs. We examine this in light of evidence from 73 public PhD-granting political science departments across the country. We find that the existence of such courses has a marginally positive effect on placement rates, particularly with regards to the placement rates of lesser ranked research departments at primarily teaching institutions. However, the most consistent predictor of placement rates across all models is the research productivity of the graduate department from which the students received their degree.
Artinian Level Algebras of Low Socle Degree

In this article we study Hilbert functions and isomorphism classes of Artinian level local algebras via Macaulay's inverse system. Upper and lower bounds concerning numerical functions admissible for level algebras of fixed type and socle degree are known. For each value in this range we exhibit a level local algebra with that Hilbert function, provided that the socle degree is at most three. Furthermore, we prove that level local algebras of socle degree three and maximal Hilbert function are graded. In the graded case, the extremal strata have been parametrized by Cho and Iarrobino.
Shaped Ultrafast Laser Pulses in the Deep Ultraviolet

We use an acousto-optic pulse shaper to programmable control the phase and amplitude of femtosecond laser pulses in the deep ultraviolet (260 nm). These pulses will be used in molecular coherent control experiments.
Suppression of serum thyrotropin (TSH) by L-dopa in chronic hypothyroidism: interrelationships in the regulation of TSH and prolactin secretion.

Synthetic thyrotropin releasing hormone (TRH) stimulates the release of human thyrotropin (TSH) and prolactin (HPr). Though acute administration of l-dopa inhibits HPr release, it has failed to produce discernible changes of serum TSH in euthyroid men. We have examined the effect of acute administration of l-dopa on TSH secretion in 8 women with primary hypothyroidism of at least 1 yr duration. Serum TSH decreased with 24–60% of the basal value at 2-4-hr after l-dopa administration. The mean decrease for the entire group was 36.9% ± 5.3 SEM at 4 hr. Changes in serum HPr occurred in parallel with those of serum TSH. Treatment with 100 ng of T3 per day for 1-1/2 to 2 days produced a gradual diminution in basal serum TSH levels and resulted in a decreased absolute serum TSH but not serum HPr response to TRH. l-dopa had no effect on the peripheral metabolism of T4. The observed suppressive effect of l-dopa on serum TSH in hypothyroid patients might be due to an inhibition of endogenous TRH secretion, a direct...
Properties of low order transverse modes in argon ion lasers.

A study has been conducted to determine the trade-offs among beam divergence, output power, and mirror alignment tolerances of high power argon ion lasers operating in various low order transverse modes. The radial intensity distribution and angular divergence of the actual laser modes from the active cavity have been measured and are compared with the theoretical passive cavity modes. The intensity distributions of higher order laser modes are found to differ markedly from those predicted by theory. The differences consist primarily of enhancement of the intensity of the off-axis peaks relative to that of the center peaks. These differences are caused by the relative high small-signal gain and the saturable gain characteristics of the medium. The beam divergence in free space of different transverse modes agrees very closely with that predicted for the passive cavity modes. The three lowest order transverse modes (i.e., TEM00, TEM01*, and TEM10) diverge at 1.1, 2.4, and 3.6 times the rate of a diffraction limited gaussian beam having the same diameter at the 1/e2 intensity points. The mirror alignment tolerances associated with different transverse modes have been measured for both double concave and plano concave cavity configurations using a wide variety of spherical mirrors. For a given cavity configuration, as the order of the transverse mode increases, the alignment requirements become progressively less stringent. In accordance with theory, the alignment tolerances are found to be less severe for double concave cavities than for plano concave cavities. For a given cavity configuration, higher order transverse modes have a larger beam diameter and consequently couple to a larger volume of the laser medium. Therefore, a greater power output may be obtained in a given length by using a higher order transverse mode. Data on the relative power available in different transverse modes as a function of cavity configuration are given. A knowledge of the trade-offs among beam divergence, cavity stability, and power output for different transverse modes allows the optimum transverse mode and cavity configuration for a given laser application to be selected.
System-on-chip integration

Numerous "signal-processing products" are now driving the semiconductor market for SOC solutions enabling real-time performance, low-cost, low-power, portability, etc. A primary limit on the types of electronic (or other) functions that will be integrated into future SOCs is cost of integration, which tends to grow non-linearly with process complexity and chip area. A near-continuum of System-on/in-X solutions is emerging between traditional System-on-Chip and System-on-Board. These approaches span the tradeoff between bandwidth and cost. For the foreseeable future, digital CMOS will continue to serve as a "host platform" for integrating a wide range of mechanical, optical, biological, and, perhaps, even "quantum" technologies.
Pulse polarization splitting in a transient wave plate

We demonstrate propagation of ultrafast laser pulses through a molecular gas acting as a transient wave plate under conditions of strong phase modulation. A single, linearly polarized pulse is split into two distinct laser pulses.
A length operator for canonical quantum gravity

We construct an operator that measures the length of a curve in four-dimensional Lorentzian vacuum quantum gravity. We work in a representation in which an SU(2) connection is diagonal and it is therefore surprising that the operator obtained after regularization is densely defined, does not suffer from factor ordering singularities, and does not require any renormalization. We show that the length operator admits self-adjoint extensions and compute part of its spectrum which, like its companions, the volume and area operators already constructed in the literature, is purely discrete and roughly quantized in units of the Planck length. The length operator contains full and direct information about all the components of the metric tensor which facilitates the construction of so-called weave states which approximate a given classical three-geometry.
Enhanced channel modulation in dual-gated silicon nanowire transistors.

Dual-gated silicon nanowire (SiNW) field-effect transistors (FETs) have been fabricated by using electron-beam lithography. SiNW devices (W ≈ 60 nm) exhibit an on/off current ratio greater than 106, which is more than 3 orders of magnitude higher than that of control devices prepared simultaneously having a large channel width (∼5 μm). In addition, by changing the local energy-band profile of the SiNW channel, the top gate is found to suppress ambipolar conduction effectively, which is one of the factors limiting the use of nanotube or nanowire FETs for complimentary logic applications. Two-dimensional numerical simulations show that the gate-induced electrostatic control is improved as the channel width of the FETs decreases. Therefore, enhanced channel modulations can be achieved in these dual-gated SiNW devices.
Transmetalation of tetranuclear copper(I) complexes with an Fe(NS)3 reagent

Abstract Stoichiometric transmetalation of tetranuclear copper(I) complexes N4Cu4X4 (I; N = N,N-diethyl- nicotinamide; X  Cl or Br) by 1 mol or excess tris(S- methyl isopropylidenehydrazinecarbodithioato)iron- (III) (Fe(NS)3, IIa) in aprotic solvents under dinitrogen is preceded by electron transfer from copper- (I) to iron(III) and gives tetranuclear iron(II)-containing products: I + IIa → N4Cu2ICuIIFeII(NS)2X4 (III′) + Cu(NS)(s). The rates of reaction of I with M(NS)3 and M(NS)2 reagents (M = Co, Ni, Cu, Zn) decrease in the order Co(NS)3 (II) > IIa > M(NS)2. Products III′ react stoichiometrically with 1 mol of II or M(NS)2 or with 2 mols of II or M(NS)2 to give iron(III)-containing dimers N4MFe(OH)X4 (VIII′) and trimers N3M2Fe(OH)X4O (X′), respectively, after oxidation with dioxygen and isolation. Transmetalation of III′ with equimolar mixed transmetalators M(NS)2 and M′(NS)2 is selective but gives dimers N4MM′X4 instead of VIII′ because Fe(NS)2 is more thermodynamically stable than M′(NS)2. Aprotic oxidation of III′ by dioxygen proceeds in two distinct stages, the first corresponding to four-electron oxidation of the two copper(I) and two coordinated NS ligands of III′ and the second to oxidation of the iron(II) center of III′. The isolated oxidation products are (μ4-O, μ-O)N4- Cu3Fe(OH)X4 (IV′). Products IV′ characteristically lose 1 mol CuO on transmetalation with 2 mol of M(NS)2 or II to give trimers X′. Products IV′ also react with 1 or 2 mol of Fe(NS)3 to give trimers (μ3-O)N3Fe(OH)CuFe(NS)X4 (XI′) and (μ3-O)N3Fe(OH)(Fe(NS))2X4 (XII′), respectively. The major differences between Co(NS)3 and Fe(NS)3 as transmetalators of I, III′ and IV′ are (i) lack of reaction of III and III′ with excess Fe(NS)3; (ii) facile oxidation of iron(II) in transmetalated products by dioxygen; (iii) case of transmetalation of these iron(II) centers with M(NS)2; (iv) stability of Fe(NS) centers in transmetalated products XI′ and XII′.
Perspectives in total synthesis: a personal account

Abstract Endeavors in total synthesis provide unique opportunities to discover and invent new strategies and tools for constructing organic molecules and they shape the art, science, and technology of chemical synthesis. In this article, the author reflects back on his career highlighting a number of lucrative campaigns in this field and their impact on chemistry, biology and medicine.
The number field sieve for integers of low weight

We define the weight of an integer N to be the smallest w such that N can be represented as Σ w i=1 ∈ i 2 ci , with ∈ 1 ,..., ∈ w ∈ {1,—1}. Since arithmetic modulo a prime of low weight is particularly efficient, it is tempting to use such primes in cryptographic protocols. In this paper we consider the difficulty of the discrete logarithm problem modulo a prime N of low weight, as well as the difficulty of factoring an integer N of low weight. We describe a version of the number field sieve which handles both problems. In the case that w = 2, the method is the same as the special number field sieve, which runs conjecturally in time exp(((32/9) 1/3 +o(1))(log N) 1/3 (log log N) 2/3 ) for N→ oo. For fixed w > 2, we conjecture that there is a constant ξ less than (32/9) 1/3 ((2w - 3)/(w - 1)) 1/3 such that the running time of the algorithm is at most exp((ξ + o(1))(log N) 1/3 (log log N) 2/3 ) for N →∞. We further conjecture that no ξ less than (32/9) 1/3 ((√2w - 2√2 + 1)/(w - 1)) 2/3 has this property. Our analysis reveals that on average the method performs significantly better than it does in the worst case. We consider all the examples given in a recent paper of Koblitz and Menezes and demonstrate that in every case but one, our algorithm runs faster than the standard versions of the number field sieve.
Colorectal cancer screening and surveillance practices by primary care physicians: results of a national survey.

Colorectal cancer screening and surveillance practices by primary care physicians: results of a national survey
Fencing the Forest: Conservation and Ecological Change in India's Central Provinces 1860-1914

The extensive woodlands of the Central Provinces of India became vital to imperial interests in the late nineteenth century, and this book argues that it was protection of these interests, rather than conservation per se that was at the heart of imperial forestry in India.
Stock returns and volatility: An empirical investigation of the German and French equity markets

This paper examines the relationship between stock returns and volatility in the German and French equity markets. Under the assumption of a conditional student t density function, the results indicate that stock returns in both countries may be described by the GARCH (1,1) model. The results also provide evidence that the 1987 stock market crash affected the mean-variance relationship in both countries, and the model's fit is significantly improved by explicitly taking the crash into account. Interestingly, the index of relative risk aversion is positive in both countries but is only significant in Germany when the stock market crash is incorporated into the analysis. The results also reveal that settlement delays significantly affect return in both countries and volatility in France. Furthermore accounting for structural shifts is important in ascertaining the relationship between stock returns and volatility.
Emittance, brilliance, and bandpass issues related to an inclined crystal monochromator

The inclined double crystal monochromator arrangement is very effective in handling high heat loads and holds considerable promise as a monochromator for undulator beams at third generation synchrotrons. Results for the ideal inclined crystal case have been obtained by dynamical diffraction calculations, and diffraction results for the (111) reflection of silicon are presented for an inclination angle of 85{degree}0 and energies of 5 key and 13.84 key. The diffraction characteristics resemble closely diffraction from-asymmetric (111) plane of silicon. However, the inclined and noninclined cases are not identical. Diffraction in the inclined case is slightly different due to refraction. The full width at half maximum of the Darwin-Prins reflectivity curve is slightly increased ({approximately}l%), and the angles of the outgoing beam after one reflection are slightly altered. That is, except for a wave incident at the Laue point in reciprocal space, the diffraction is always slightly asymmetric. The effect can be exactly reversed by an identical second crystal in the (+,{minus}) arrangement.
Application of the β-azidonation reaction to the synthesis of the antitumor alkaloid (+)-pancratistatin

Abstract o-Vanillin 21 was converted into 24 following literature procedures. Treatment of 24 withn-BuLi/THF followed by addition of 25 gave 26 . Dehydration (POCl 3 /pyridine/DBU), hydrogenation and hydrolysis of 26 gave the ketone 29 . Chirality was introduced by deprotonation of 29 with the lithium salt of (+)-bis(α-methylbenzyl)amine, followed by triisopropylsilyl trifluoromethanesulfonate to give 30 (95%). β-Azidonation of 30 with (PhIO) n /TMSN 3 rapidly produced 31 (95%) as a mixture of trans - and cis - diastereomers in a 3.5:1 ratio. Reduction with LiAlH 4 followed by methyl chloroformate/pyridine gave 32 , which on treatment with MCPBA/CH 2 Cl 2 /imidazole resulted in 33 . Hydrolysis of 33 gave 34 , which when exposed to KOBu t /HMPA at 90 °C resulted in 39 . After conversion of 39 into enone 42 , epoxidation with NaHCO 3 /H 2 O 2 /MeOH gave 43 . Reduction of 43 with L-selectride followed by solvolysis with sodium benzoate in water gave 46 , which was immediately acetylated to give 47 . Lactam formation (Tf 2 O/DMAP) converted 47 into 48 and the regioisomer 49 (7:1). The mixture of 48 and 49 demethylated to give 50 and the acetate protecting groups removed to give (+)-pancratistatin 1 . The synthesis of pancratistatin from the prochiral ketone 1 using a chiral base to generate a chiral enolate derivative is described. Download full-size image
Neutron diffraction study of the deformation mechanisms of the uranium–7 wt.% niobium shape memory alloy

Abstract The shape memory effect (SME) has been reported in the uranium–niobium alloy system in the region of the phase diagram surrounding U–6.5 wt.% Nb. In this regime, the material may have either an α″ monoclinic (U–6 wt.% Nb), or γ0 tetragonal structure (U–7 wt.% Nb) and is two phase near 6.5 wt.% niobium. In situ neutron diffraction studies during uniaxial compressive loading of U–7 wt.% Nb indicate that strain in the recoverable region is accommodated by both motion of existing twin boundaries within γ0-phase and stress-induced phase transformation from the γ0 to the α″ structure. The volume fraction of the γ0-phase decreases from 100% initially to ∼26% after 4% total strain and some reversion is observed on release. The initial stress state of the stress-induced α″ grains will be discussed as well as the load sharing between the two phases.
Quantitative analysis of tetramethylenedisulfotetramine (tetramine) spiked into beverages by liquid chromatography-tandem mass spectrometry with validation by gas chromatography-mass spectrometry

Tetramethylenedisulfotetramine, commonly known as tetramine, is a highly neurotoxic rodenticide (human oral LD(50) = 0.1 mg/kg) used in hundreds of deliberate and accidental food poisoning events in China. This paper describes a method for the quantitation of tetramine spiked into beverages, including milk, juice, tea, cola, and water, with cleanup by C8 solid phase extraction and liquid-liquid extraction. Quantitation by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) was based upon fragmentation of m/z 347 to m/z 268. The method was validated by gas chromatography-mass spectrometry (GC-MS) operated in selected ion monitoring mode for ions m/z 212, 240, and 360. The limit of quantitation was 0.10 μg/mL by LC-MS/MS versus 0.15 μg/mL for GC-MS. Fortifications of the beverages at 2.5 and 0.25 μg/mL were recovered ranging from 73 to 128% by liquid-liquid extraction for GC-MS analysis, from 13 to 96% by SPE, and from 10 to 101% by liquid-liquid extraction for LC-MS/MS analysis.
Coping with Insidious Injuries: The Case of Johns-Manville Corporation and Asbestos Exposure

Litigation involving the Johns-Manville Corporation and asbestos related diseases shows the complexity of dealing with the growing problem of insidious injuries. These are injuries, often large scale, in which the causes are rendered obscure by (a) a latency period, (b) manifestation only in a segment of the exposed population, (c) manifestation in heightened risk of diseases for which there are other causes, and/or (d) the social and spatial dispersion of the injured people. Powerful corporate actors like Johns-Manville are shown to be able to postpone and sometimes escape liability, but also to embody the potential capacity to pay compensation to victims of long-latent disease. Johns-Manville's bankruptcy reorganization was not a travesty of justice, as has been alleged, but a way of balancing the interests of present and future victims. A tension between goals of compensation and deterrence or punishment is revealed. We argue that minimizing insidious injuries depends less on punishment than on effective data collection, analysis, and public dissemination. Incentives are needed to make managers give early and full information about dangerous products and processes, but the threat of tort litigation can have the unintended consequence of leading managers to withhold information and assistance from victims for fear of lawsuits.
Fifty Years of Research in Sulfur Chemistry

Abstract Marvin Carmack was born in 1913 near Dana, Vermillion County, Indiana, U.S.A., and attended public schools there. He graduated from the University of Illinois in 1937 with A.B. Honors in Chemistry. During 1937–40 he earned the M.S. and Ph.D. degrees at the University of Michigan, working with Professor Werner E. Bachmann on the synthesis of substituted benzopyrene compounds as potential carcinogens. At Michigan he carried out his first experiments with the Willgerodt Reaction, which remained one continuing subject of his interest for the next fifty years-an interest that broadened to include many aspects of sulfur chemistry. A year of post-doctoral research with Professor Roger Adams at the University of Illinois dealt with the isolation and determination of structures of alkaloids of the Crotalaria and Senecio species. This research resulted in the revision of the structure of retronecine, the common subunit of most of these alkaloids. In 1941 he joined the Faculty of Chemistry in the Towne Scie...
Firehose instability near substorm expansion-phase onset?

[1] The evolution of plasma ejected earthward from a patch of reconnection at ∼25 RE is studied using a double-adiabatic-MHD simulation of a thin filament. Firehose instability occurs in the simulation after a compressional shock reflects from the near-Earth region. The tailward-propagating compressional wave, which brakes the earthward flow in the filament, is characterized by strong magnetic fluctuations. Within the context of the Near-Earth-X-Line model of substorms, we suggest that firehose instability might cause the intense magnetic-field fluctuations observed in the inner plasma sheet at substorm onset.
Dynamical analysis of S&P500 momentum

Abstract The dynamics of the S&P500 price signal is studied using a moving average technique. Particular attention is paid to intersections of two moving averages with different time horizons. The distributions of the slopes and angle between two moving averages at intersections is analyzed, as well as that of the waiting times between intersections. In addition, the distribution of maxima and minima in the moving average signal is investigated. In all cases, persistent patterns are observed in these probability measures and it is suggested that such variables be considered for better analysis and possible prediction of the trends of the signal.
Tight Beltrami fields with symmetry.

Let M be a compact orientable Seifered fibered 3-manifold without a boundary, and α an S1-invariant contact form on M. In a suitable adapted Riemannian metric to α, we provide a bound for the volume Vol(M) and the curvature, which implies the universal tightness of the contact structure ξ = ker α.
An AdS/dS duality for a scalar particle☆

Abstract The motion of a scalar particle in ( d +1)-dimensional AdS space may be described in terms of the Cartesian coordinates that span the ( d +2)-dimensional space in which the AdS space is embedded. Upon quantization, the mass hyperboloid defined in terms of the conjugate momenta turns into the wave equation in AdS space. By interchanging the roles of coordinates and conjugate momenta in the ( d +2)-dimensional space we arrive at a dual description. For massive modes, the dual description is equivalent to the conventional formulation, as required by holography. For tachyonic modes, this interchange of coordinates and momenta establishes a duality between Euclidean AdS and dS spaces. We discuss its implications on Green functions for the various vacua.
Diastereoselective bromodifluoromethylation of chiral imide enolates via insertion of difluorocarbene

Abstract The bromodifluoromethylation of lithium enolates of chiral N-acyloxazolidinones via the insertion of difluorocarbene proceeds with good diastereomeric excess (68–92% de).
Neutron generators developed at LBNL for homeland security and imaging applications

Abstract The Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory has developed various types of advanced neutron generators for wide range of applications. The latest developments include a T–T fusion reaction based point neutron generator for Tensor Technology Inc. for airport cargo screening and a single beam, D–D fusion based axial neutron generator for neutron imaging applications for Adelphi Technology Inc. These neutron generators utilize RF-induction discharge to ionize the deuterium/tritium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. Stability of the discharge allows for accurate modeling of the beam dynamics in accelerator section of these neutron generators. Current status of the neutron generator development with experimental data will be presented.
Experiments on the origin of molecular chirality by parity non-conservation during beta-decay

Experiments are described to test a theory for the origin of optical activity wherein the longitudinally polarized electrons resulting from parity violation during radioactive s-decay, and their resulting circularly polarized Bremsstrahlung, might interact asymmetrically with organic matter to yield optically active products. The historical background to this subject is briefly reviewed. Our experiments involve subjecting a number of racemic and optically active amino acid samples to irradiation in a 61700 Ci90Sr-90Y s-radiation source for a period of 1.34 years (total dose: 4.11 × 108 rads), then examining them for any asymmetric effects by means of optical rotatory dispersion and analytical gas chromatography. In the cases of D,L-leucine, norleucine, norvaline and proline as solids, of D,L-leucine in solution (neutral and as Na and HCl salts) and of D,L-tyrosine in alkaline solution no optical rotation was observed during ORD measurements in the 250–630 nm spectral region. While slight differences were noted in the percent radiolysis of solid D- (12.7%) and L-leucine (16.2%) as determined by GC, no enrichment of either enantiomer was found by GC analyses of irradiated D,L-leucine, either as a solid (13.7% radiolyzed) or as its Na salt (48.6% radiolyzed) or HCl salt (34.6% radiolyzed) in aqueous solution. Several explanations are offered for our experimental findings.
3D XY scaling theory of the superconducting phase transition

Abstract The intermediate 3D XY scaling theory of superconductivity at zero and nonzero magnetic fields is developed, based only upon the dimensional hypothesis B∼(Length)−2. Universal as well as nonuniversal aspects of the theory are identified, including background terms and demagnetization effects. Two scaling regions are predicted: an `inner' region (very near the zero field superconducting transition, Tc), where the fields B, H, and Hex differ substantially, due to the presence of diamagnetic fluctuations; and an `outer' region (away from Tc), where the fields can all be treated similarly. The characteristic field (H0) and temperature (t1) scales, separating the two regimes, are estimated. Scaling theories of the phase transition line, magnetization, specific heat, and conductivity are discussed. Multicritical behavior, involving critical glass fluctuations, is investigated along the transition line, Tm(B), at nonzero fields.
Aldol reaction via in situ olefin migration in water

Abstract In the presence of a catalytic amount of RuCl2(PPh3)3, aldehydes reacted with allyl alcohols to give aldol-type products in water and under an atmosphere of air.
Optimizing multi-station earthquake template matching through re-examination of the Youngstown, Ohio, sequence

Abstract A series of earthquakes in 2011 near Youngstown, OH, has been a focal point for discussions of seismicity induced by a nearby wastewater disposal well. Utilizing an efficient waveform template matching procedure, the optimal correlation template to study the Youngstown sequence was identified by varying parameters such as the stations utilized, frequency passband, and seismogram length. A catalog composed of 566 events was identified between January 2011 and February 2014. Double-difference relocation refines seismicity to a ∼800 m linear streak from the Northstar 1 injection well to the WSW along the same strike as the fault plane of the largest event. Calculated Gutenberg–Richter b-values are consistent with trends observed in other regions with seismicity induced by fluid injection.
Critical exponent for the viscosity of carbon dioxide and xenon

The viscosities of carbon dioxide and xenon have been measured near their critical points and the critical exponent y characterizing the asymptotic divergence has been determined. Both fluids yielded exponents in the range y = 0.041 + or - 0.001 and thus also fell in the range y = 0.042 + or - 0.002 from an earlier study of four binary liquids. This agreement between experiments is the first evidence that pure fluids and binary liquids are in the same dynamic universality class. A recent theoretical value for y is 0.032. The 30 percent discrepancy is much greater than the combined errors from experiment and theory. The torsion oscillator viscometer operated at low frequency and low shear rate to avoid systematic errors caused by critical slowing down. Far from T(c) the analysis accounted for the crossover from critical to noncritical temperature dependence, where the latter was obtained from previously published correlations. Corrections for gravitational stratification were included close to T(c).
A new class of highly cytotoxic diketopiperazines.

The discovery of a novel class of diketopiperazines possessing potent cytotoxic activity is described.
Preferences for crop insurance when farmers are diversified

The government intends to rely on an insurance-based solution to yield risk, therefore, it is important to identify which characteristics most effect a grower's decision regarding whether or not to use crop insurance. This case study uses California cross sectional survey data to directly compare the relative effects of three types of characteristics which are expected to influence insurance preferences. In general, results from the model estimated indicate that preferences for crop insurance are a function of both the commodities produced and the risk environment faced by individual growers.
The Moving Home Effect: A Quasi Experiment Assessing Effect of Home Location on the Offence Location

Objectives This study aims to test whether the home location has a causal effect on the crime location. To accomplish this the study capitalizes on the natural experiment that occurs when offender’s move, and uses a unique metric, the distance between sequential offenses, to determine if when an offender moves the offense location changes.
Crystal fields and the γ→α transition in Ce

Abstract In the γ → α transition of Ce, the material undergoes an isostructural change at which the volume changes by 15% and the magnetic character changes. Recently, the transition has been described in terms of a balance between the free-energy of the magnetic moments and the characteristic energy scale of the α phase. The field-temperature dependence of the phase diagram has been predicted, and was confirmed by experiment. Inelastic neutron scattering experiments on the γ phase of Ce have shown indications of crystal field splittings, and similar experiments have determined the energy scale of the α phase. We shall examine the effects of the crystalline field splittings within the framework of NCA calculations on the single-impurity Anderson model, and examine their consequence for the phase diagram.
Long-Range Forces and Neutrino Mass

We explore the limits on neutrino mass which follow from a study of the long-range forces that arise from the exchange of massless or ultra-light neutrinos. Although the 2-body neutrino-exchange force is unobservably small, the many-body force can generate a very large energy density in neutron stars and white dwarfs. We discuss the novel features of neutrino-exchange forces which lead to large many-body effects, and present the formalism that allows these effects to be calculated explicitly in the Standard Model. After considering, and excluding, several possibilities for avoiding the unphysically large contributions from the exchange of massless neutrinos, we develop a formalism to describe the exchange of massive neutrinos. It is shown that the stability of both neutron stars and white dwarfs in the presence of many-body neutrino-exchange forces implies a lower bound, {ital m}{vert_bar}{approx_gt}0.4 eV/{ital c}{sup 2} on the mass {ital m} of any neutrino. {copyright} 1996 by Academic Press, Inc.
The chemistry of activated bleomycin

The bleomycins are a structurally related class of antitumour antibiotics that are utilised extensively for the treatment of human malignancies1,2. In common with many antitumour agents, the cellular locus for the action of bleomycin is thought to be DNA. More specifically, bleomycin can be activated for DNA strand scission and this transformation is believed to constitute the basis for the therapeutic utility of this class of compounds2–7.
The Simplest little Higgs

We show that the SU(3) little Higgs model has a region of parameter space in which electroweak symmetry breaking is natural and in which corrections to precision electroweak observables are sufficiently small. The model is anomaly free, generates a Higgs mass near 150 GeV, and predicts new gauge bosons and fermions at 1 TeV.