cssi/SciSciGPT-SciSciNet huggingface dataset:
Measures of impulsivity in cigarette smokers and non-smokers

Rationale: Drug users are thought to be more ”impulsive” than non-users. Objectives: This study examined whether regular smokers are more impulsive than never smokers using personality and behavioral measures of impulsivity. Methods: Twenty regular smokers (≥15 cigarettes/day) and 20 never smokers were recruited. Participants completed five personality questionnaires to assess impulsivity: Adjective Checklist, Barratt’s Impulsivity Scale, the Tridimensional Personality Questionnaire, Eysenck’s Personality Questionnaire, and the Sensation-Seeking Scale. Participants also performed three behavioral choice tasks designed to assess impulsivity. In the delay task, participants chose between small, immediate and large, delayed monetary rewards. Impulsivity was defined as a relative preference for the small, immediate alternative. In the probability task, participants chose between small, certain and large, uncertain monetary rewards. Impulsivity was defined as a relative preference for the large but more risky alternative. In the work task, participants chose between small monetary rewards obtained by performing a negligible amount of work and a larger amount of money requiring more work. Impulsivity was defined as a relative preference for the smaller, easier alternative. Results: On the personality questionnaires, smokers had statistically higher impulsivity scores on most scales. On the behavioral choice tasks, smokers chose small, immediate money over large, delayed money more frequently, signifying greater levels of impulsivity. There were no differences between the groups’ choices on the other tasks. Correlations between questionnaire and task data were small, as were correlations between data from each task. Conclusions: Together, these results indicate that the smokers were more impulsive than never smokers.
Coronaviruses Resistant to a 3C-Like Protease Inhibitor Are Attenuated for Replication and Pathogenesis, Revealing a Low Genetic Barrier but High Fitness Cost of Resistance

Viral protease inhibitors are remarkably effective at blocking the replication of viruses such as human immunodeficiency virus and hepatitis C virus, but they inevitably lead to the selection of inhibitor-resistant mutants, which may contribute to ongoing disease. Protease inhibitors blocking the replication of coronavirus (CoV), including the causative agents of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), provide a promising foundation for the development of anticoronaviral therapeutics. However, the selection and consequences of inhibitor-resistant CoVs are unknown. In this study, we exploited the model coronavirus, mouse hepatitis virus (MHV), to investigate the genotype and phenotype of MHV quasispecies selected for resistance to a broad-spectrum CoV 3C-like protease (3CLpro) inhibitor. Clonal sequencing identified single or double mutations within the 3CLpro coding sequence of inhibitor-resistant virus. Using reverse genetics to generate isogenic viruses with mutant 3CLpros, we found that viruses encoding double-mutant 3CLpros are fully resistant to the inhibitor and exhibit a significant delay in proteolytic processing of the viral replicase polyprotein. The inhibitor-resistant viruses also exhibited postponed and reduced production of infectious virus particles. Biochemical analysis verified double-mutant 3CLpro enzyme as impaired for protease activity and exhibiting reduced sensitivity to the inhibitor and revealed a delayed kinetics of inhibitor hydrolysis and activity restoration. Furthermore, the inhibitor-resistant virus was shown to be highly attenuated in mice. Our study provides the first insight into the pathogenicity and mechanism of 3CLpro inhibitor-resistant CoV mutants, revealing a low genetic barrier but high fitness cost of resistance. IMPORTANCE RNA viruses are infamous for their ability to evolve in response to selective pressure, such as the presence of antiviral drugs. For coronaviruses such as the causative agent of Middle East respiratory syndrome (MERS), protease inhibitors have been developed and shown to block virus replication, but the consequences of selection of inhibitor-resistant mutants have not been studied. Here, we report the low genetic barrier and relatively high deleterious consequences of CoV resistance to a 3CLpro protease inhibitor in a coronavirus model system, mouse hepatitis virus (MHV). We found that although mutations that confer resistance arise quickly, the resistant viruses replicate slowly and do not cause lethal disease in mice. Overall, our study provides the first analysis of the low barrier but high cost of resistance to a CoV 3CLpro inhibitor, which will facilitate the further development of protease inhibitors as anti-coronavirus therapeutics.
HPLC analysis of desmosterol, 7-dehydrocholesterol, and cholesterol.

A simple and sensitive method to analyzed mixtures of desmosterol, 7-dehydrocholesterol and cholesterol is described. The method involves the oxidative conversion of the sterols with cholesterol oxidase, followed by high performance liquid chromatographic (HPLC) analysis. A C18 reversed phase column (3 μm, 75×4.6 mm) and a mixture of methanol and acetonitrile (1∶1, v/v) at a rate of 1 ml/min are used to separate the sterols. The eluted sterols are quantified by measuring UV absoprtion at 240 nm. As little as 10 pmoles of sterol can be quantified under these conditions.
The geometry of indefinite J-spaces and stability behavior of linear systems☆

Abstract The study of stability behavior of the canonical system ( ∗ ) X = iJH(t)X is closely linked to the geometrical properties of indefinite J-spaces. Using results from the theory of indefinite J-spaces and studying the locus of the spectrum of the monodromy operator of (∗) we provide several new sufficient conditions for stability behavior of (∗) and its special forms. Moreover, we extend M. G. Neǐgauz and V. B. Lidskiǐ's criterion to the infinite-dimensional case. To study stability criteria for the system ( ∗∗ ) p(D)x + ƒ(t) q(D)x = 0 , under suitable conditions we transform (∗∗) into a Hamiltonian system and then use stability criteria for Hamiltonian systems to obtain several new stability criteria. These new stability criteria generalize or are related to R. W. Brockett's criterion. We also give some relationships between system (∗∗) and Hamiltonian systems. Moreover, via classical methods we obtain several new stability criteria for (∗∗) which are related to the Nyquist criterion and circle criteria (Brockett).
Urachal duct remnant-like umbilical clear cell acanthoma in an infant: an unusual presentation and pitfall in clinical practice.

Background Although an umbilical nodule is common in neonates and young infants, an umbilical nodule of poor therapeutic response will increase the likelihood of other uncommon etiology. Clear cell acanthoma (CCA) has never been described as an oozing umbilical nodule on infants. Methods To present a case of CCA which occurred on an 8-month-old female infant presenting with one weeping nodule on the umbilicus since early neonate. The lesion underwent skin biopsy and subsequent hematoxylin-eosin and periodic acid-Schiff staining. Result Three courses of liquid nitrogen cryosurgery were performed after the diagnosis of CCA was confirmed. The lesion resolved rapidly. Conclusion This report presents the first and youngest case of umbilical CCA in the English literature. This case supports the inflammatory dermatosic nature of CCA.
Microwave, Raman and infrared spectra, r0 structural parameters, conformational stability, and ab initio calculations of cyclobutylisocyanate

The microwave spectrum of cyclobutylisocyanate, c-C4H7NCO, has been investigated from 21,000 to 11,000 MHz and 11 transitions for the more stable equatorial-trans conformer were assigned. The rotational constants of the ground vibrational state have been determined and the molecule has been shown to be a near symmetric prolate rotor (К = −0.99). The B and C rotational constants have been confidently determined to be B = 1508.68(3) and C = 1476.55(2) MHz, respectively, whereas the value for the A rotational constant of 6,891(302) MHz had a large uncertainty. Variable temperature (−100 to −55 °C) studies of the infrared spectra (3,500–400 cm−1) of cyclobutylisocyanate dissolved in liquid xenon as well as the infrared spectra of the gas and solid have been recorded. In addition, the Raman spectra (3,600–100 cm−1) of the liquid have been investigated. These spectral data indicated the present of three conformers in the fluid states which are the equatorial-trans, equatorial-gauche, and axial-trans forms. The second part of the conformational name refers to the relative position of the NCO moiety relative to the alpha hydrogen. By utilizing four conformer pairs, an enthalpy difference of 131 ± 13 cm−1 (1.57 ± 0.16 kJ/mol) was obtained with the equatorial-trans conformer the more stable form, which is in good agreement with the ab initio predicted value of 137 ± 36 cm−1 (1.64 ± 0.43 kJ/mol). To aid in the vibrational assignment, ab initio and DFT calculations have been carried out by using a variety of basis sets up to 6-311G(3df,3pd).
Microstructural Evolution in Orthotropic Elastic Media

We consider the problem of microstructural evolution in binary alloys in two dimensions. The microstructure consists of arbitrarily shaped precipitates embedded in a matrix. Both the precipitates and the matrix are taken to be elastically anisotropic, with different elastic constants. The interfacial energy at the precipitate?matrix interfaces is also taken to be anisotropic. This is an extension of the inhomogeneous isotrpic problem considered by H.-J. Jou et al. (1997, J. Comput. Phys.131, 109). Evolution occurs via diffusion among the precipitates such that the total (elastic plus interfacial) energy decreases; this is accounted for by a modified Gibbs?Thomson boundary condition at the interfaces. The coupled diffusion and elasticity equations are reformulated using boundary integrals. An efficient preconditioner for the elasticity problem is developed based on a small scale analysis of the equations. The solution to the coupled elasticity-diffusion problem is implemented in parallel. Precipitate evolution is tracked by special non-stiff time stepping algorithms that guarantee agreement between physical and numerical equilibria. Results show that small elastic inhomogeneities in cubic systems can have a strong effect on precipitate evolution. For example, in systems where the elastic constants of the precipitates are smaller than those of the matrix, the particles move toward each other, where the rate of approach depends on the degree of inhomogeneity. Anisotropic surface energy can either enhance or reduce this effect, depending on the relative orientations of the anisotropies. Simulations of the evolution of multiple precipitates indicate that the elastic constants and surface energy control precipitate morphology and strongly influence nearest neighbor interactions. However, for the parameter ranges considered, the overall evolution of systems with large numbers of precipitates is primarily driven by the overall reduction in surface energy. Finally, we consider a problem related to the microstructure of fully orthotropic geological materials.
Characterization of photopolymerized decyl methacrylate as a membrane matrix for ion‐selective electrodes

Potentiometric ion-selective sensors based on photopolymerized thin films of decyl methacrylate (DMA) crosslinked with hexanedioldimethacrylate (HDDMA) are described. The electrochemical response characteristics including slopes, selectivities, resistances and response times of several DMA-based ion-selective electrodes are reported and compared to those obtained using PVC-based sensors. Sensors incorporating the nonspecific anion exchanger tridodecylmethylammonium chloride and the plasticizer dioctyl sebacate exhibit a Nernstian response to chloride with the expected Hofmeister selectivity pattern. Additional response data for potassium and carbonate selective sensors prepared with the electrically neutral ionophores valinomycin and p-decyltrifluoroacetophenone, respectively, are also presented. The eflects of endogenous anionic sites arising from dissociated methacrylic acid impurities within the membrane matrix are discussed. The degree of site dissociation and its resulting contributions to the EMF response-governing equilibria are considered in detail. It is shown that such sites must be electrically compensated (via addition of adequate lipophilic cationic sites) when preparing neutral- carrier based anion sensors but otherwise have no apparent effect on the sensing membranes' selectivity and performance.
Cerebral Glioblastomas Can Be Cured

In 1959, a 30-year-old man underwent the removal of a glioblastoma multiforme from the right parietal lobe of his brain. After the operation, he received x-ray therapy. He made a complete recovery. Today, over 25 years later, he is alive and well and is regularly employed full-time. If glioblastomas and other cerebral gliomas are removed completely, the patients can be cured of their tumors.
Experimental Establishment of the Relativity of Time

None of the fundamental experiments on which the restricted principle of relativity is based requires for their explanation that the classical concept of absolute time be modified; the present experiment was devised to test directly whether time satisfies the requirements of relativity. It depends on the fact that if a pencil of homogeneous light is split into two components which are made to interfere after traversing paths of different length, their relative phases will depend on the translational velocity of the optical system unless the Lorentz-Einstein transformation equations are valid. Hence, such a system at a point on the earth should give rise to an interference pattern which varies periodically as the velocity of the point changes in consequence of the rotation and revolution of the earth. The effect to be expected for a small velocity is so very small that it has been necessary to devise a special source of light, an interferometer of great stability and a refinement of the technic of measuring displacements in the interference pattern. With the apparatus finally employed, we have shown that there is no effect corresponding to absolute time unless the velocity of the solar system in space is no more than about half that of the earth in its orbit. Using this null result and that of the Michelson-Morley experiment we derive the Lorentz-Einstein transformations, which are tantamount to the relativity principle.
A Magneto-Inductive Sensor Based Wireless Pharmaceutical Compliance Monitoring System

We have developed a noninvasive wireless pharmaceutical compliance monitoring (PCM) system using an array of magneto-inductive sensors around the patient's neck in the form of a necklace to detect the passage of a pill or capsule embedded with a small permanent magnet as a tracer through the esophagus upon ingestion. As a result, a signal representing "dose ingestion event" is generated and wirelessly transmitted to a data delivery device (PDA), which is carried on the patient's body. A software application running on the PDA time/date stamps the event and stores it for later retrieval by a physician. This technology provides a safe, convenient, low-cost, and accurate detection mechanism that helps patients adhere with proper dosage of their medication. It also helps pharmaceutical companies conduct new drug trials more accurately. A prototype system using off-the-shelf components has been developed and successfully tested. Preliminary results using an artificial neck showed 94.4% correct detections when the magnetic tracer passed through the detection zone and about 6% false positives for outside areas.
Consequences of dispersal heterogeneity for population spread and persistence.

Dispersal heterogeneity is increasingly being observed in ecological populations and has long been suspected as an explanation for observations of non-Gaussian dispersal. Recent empirical and theoretical studies have begun to confirm this. Using an integro-difference model, we allow an individual’s diffusivity to be drawn from a trait distribution and derive a general relationship between the dispersal kernel’s moments and those of the underlying heterogeneous trait distribution. We show that dispersal heterogeneity causes dispersal kernels to appear leptokurtic, increases the population’s spread rate, and lowers the critical reproductive rate required for persistence in the face of advection. Wavespeed has been shown previously to be determined largely by the form of the dispersal kernel tail. We qualify this by showing that when reproduction is low, the precise shape of the tail is less important than the first few dispersal moments such as variance and kurtosis. If the reproductive rate is large, a dispersal kernel’s asymptotic tail has a greater influence over wavespeed, implying that estimating the prevalence of traits which correlate with long-range dispersal is critical. The presence of multiple dispersal behaviors has previously been characterized in terms of long-range versus short-range dispersal, and it has been found that rare long-range dispersal essentially determines wavespeed. We discuss this finding and place it within a general context of dispersal heterogeneity showing that the dispersal behavior with the highest average dispersal distance does not always determine wavespeed.
Reform: Why? What? By Whom?

Benton and Hoyt have surveyed educational psychologists regarding their views on reform of teacher-training programs. Ostensibly based on the results of their survey, Benton and Hoyt have called for a greater role of educational psychologists in shaping the reform of teacher training. The present article questions: (1) whether educational psychologists have skills that would contribute to reform as it is being conceptualized; (2) whether the reform movement is focusing on aspects of the educational system that will result in improved student outcomes; and (3) whether it is the educational system that needs reform or our expectations for the educational system.
A model for estimating some of the effects of aneurysm resection following myocardial infarction: preliminary clinical confirmation.

Quantitative preoperative evaluation of potential postoperative myocardial performance after resection of an akinetic area has been difficult because the usual indices of myocardial performance provide no directly applicable information or cannot be applied because of disorders of isovolumetric contraction. Critical factors in postoperative performance are residual ventricular size and the capacity to increase fiber shortening. We have assumed that postoperative incremental fiber shortening is determined primarily by reduction in afterload secondary to reduction in ventricular volume. Using this assumption, a preoperative late systolic force-length curve can be extrapolated to form a boundary for postoperative fiber shortening after surgical unloading. Preliminary preoperative studies in human beings have adequately estimated postoperative performance and are compatible with these assumptions. Mathematical considerations developed for these purposes suggest that the relatively simple spherical model is adequate for most ventricles.
Growth and preparation of LiZnP and LiZnAs for solid-state neutron detectors

Most gas-filled neutron detectors are difficult to manufacture as compact detectors. Boron-based compounds, such as BP, BN and BAs have shown limited success, and thus far do not appear promising due to problems with crystal growth and materials preparation. Although some Li compounds have been quite successful as neutron detectors, such as LiF thermoluminescent dosimeters and LiI scintillators, neutron detectors from Li-based semiconductor compounds have not been explored to a similar extent as B-based semiconductors. In the present study, crystals of the filled tetrahedral compound class (AIBIICV) of Li semiconductors were grown, known as Nowotny-Juza compounds, such as LiZnP and LiZnAs for investigation as high efficiency compact neutron detectors. Equimolar portions of Li, Zn and P or As were sealed under vacuum (10−6 Torr) in quartz ampoules with a graphite lining. The loaded ampoules were placed into a compounding furnace and raised to 560 °C to form the ternary compound, LiZnP or LiZnAs, and further annealed to promote crystallization. The synthesized compound was crushed into a fine powder and sealed in a tantalum ampoule by arc welding. The ampoule was mounted in a vacuum chamber with a background argon pressure of 300mTorr. The ampoule was connected to a low-voltage high-current power source where the LiZnP or LiZnAs was melted and slowly cooled to crystallization. The bulk crystals were extracted, then cut, and polished for further electrical and physical property investigations.
Electroporation-mediated delivery of molecules to model intestinal epithelia

Abstract This study was conducted to determine if electroporation can deliver membrane-impermeant molecules intracellularly to intact, physiologically competent monolayers that mimic the intestinal epithelium. In addition, the long-term effects of electroporation on these monolayers were studied to determine the kinetics with which monolayers recover barrier function. Caco-2 and T84 cells were electroporated as monolayers using calcein and fluorescein-labeled bovine serum albumin as marker molecules for measuring delivery into cells. Confocal microscopy and flow cytometry were used, respectively, to visualize and quantify uptake of these molecules. Transepithelial resistance was used as a measure of physiologic barrier function. We found that intracellular uptake of calcein and bovine serum albumin occurred uniformly throughout both types of model epithelia and increased as a function of voltage, pulse length, and pulse number. There was no significant difference in uptake resulting from single and multiple pulses of the same total exposure time. We also observed that monolayers exposed to electroporation that induced uptake of up to 106 molecules/cell were able to recover normal barrier function within one day. These findings suggest that electroporation may be useful for intracellular delivery into monolayers to study epithelial biology and, possibly, for drug delivery to intestinal epithelium.
In-situ scanning tunneling microscopy observation of surfaces exhibiting ferromagnetic dipolar coupling

Abstract We have investigated a number of surfaces that exhibit dipolar coupling using in-situ STM. Co and Cu layers were characterized for their roughness and the resulting parameters were used to calculate a value for the interlayer coupling from a theoretical expression. The films were grown on Pt on Al 2 O 3 to facilitate transport measurements. Using the hysteresis loops from spin valves made from these layers, the actual coupling could be compared to the theoretical value when the surfaces were modeled as sinusoidal. The results give an order-of-magnitude agreement. The sign of the coupling is also found to vary with the deposition technique: ferromagnetic for ion-beam sputtering and antiferromagnetic for DC magnetron sputtering.
Characteristics and Performance of Prefabricated Vertical Drains for Enhanced Soil Flushing

The use of prefabricated vertical drains (PVDs) under vacuum conditions for soil flushing was investigated with soils consisting of 100 percent sand or a combination of 80 percent sand and 20 percent kaolinite. Tests of the 100 percent sand specimens indicated that the areal extent of the PVD zone of influence remained approximately 16 to 21 times the PVD-equivalent diameter (PVD circumference/π) as the extraction vacuum increased from 2.5 to 20 kPa. Tests of the sand kaolinite specimens (80/20 soil) indicated that the areal extent of the PVD zone of influence remained approximately 5 to 8 times the PVD equivalent diameter as the extraction vacuum increased from 2.5 to 20 kPa. The effective zone of influence in the 80/20 soil did not show a corresponding increase in areal extent as the vacuum pressure was increased beyond the PVD embedment depth. Pilot-scale tracer flushing tests demonstrated the feasibility of using PVDs for flushing 100 percent sand soil. The tracer testing demonstrated that longer flus...
Taxation and the urban poor in developing countries

Empirical evidence indicates that the poor, and particularly the urban poor, in developing countries pay a substantial part of their income as taxes. This paper examines critically the procedures employed in measuring the incidence of taxation in LDCs, with a particular emphasis on evidence concerning the tax burdens of the urban poor, and presents a summary of some empirical work in this area. It then provides a review and analysis of fiscal policies which at the margin can assist in improving the position of the urban poor by reducing the regressivity, and increasing the progressivity, of existing or potential revenue instruments, including public service prices, and by improving the fiscal position of the poor through expenditure programs.
Pharmacokinetics and tissue distribution of cryptophycin 52 (C-52) epoxide and cryptophycin 55 (C-55) chlorohydrin in mice with subcutaneous tumors.

To compare the pharmacokinetics and tissue distribution (both normal and tumor) of cryptophycin 52 (C-52) and its putative chlorohydrin prodrug cryptophycin 55 (C-55) in a murine model and to investigate a possible mechanism behind the superior activity of C-55. Mammary adenocarcinoma 16/c tumor-bearing mice were treated with an i.v. bolus of 11 mg/kg C-52 or 38 mg/kg C-55 in Cremophor-alcohol. At predetermined time intervals, C-52 and C-55 concentrations in plasma, liver, kidney, small intestine and tumors were measured using a previously described HPLC method. Pharmacokinetic parameters were computed using noncompartmental methods. Tissue (both normal and tumor) to plasma ratios as a function of time were also calculated for comparison. Both C-52 and C-55 were rapidly distributed into different tissues including tumors following i.v. administration. However, the affinities of these compounds towards different tissues were different. Thus, the half-lives (minutes) of C-55 were in the decreasing order liver (725), intestine (494), tumor (206), kidney (62) and plasma (44), whereas the AUC values (μg·min/ml) were in the order tumor (9077), liver (7734), kidney (6790), plasma (2372) and intestine (2234). For C-52, the half-lives (minutes) were in the decreasing order liver (1333), kidney (718), intestine (389), tumor (181) and plasma (35), and the AUC values (μg·min/ml) were in the order kidney (1164), liver (609), intestine (487), plasma (457) and tumor (442). The relative exposures to C-52 after i.v. injection of C-55 were plasma 3.9%, tumor 80.8%, kidney 3.4%, liver 1.1% and intestine 2.8%. Although plasma exposure to C-52 following C-55 administration was relatively small, the use of C-55 to deliver C-52 increased the retention of C-52 and its AUC in tumor compared to direct injection of C-52. Simultaneously, this approach shortened C-52 retention in all normal tissues studied. The distribution of C-55 and its bioconversion to C-52 in different organs and tumor tissue observed in this study suggest the ability of C-55 to target tumor tissue, creating a depot of C-52 in tumor. Increased C-52 exposure of tumor, with concomitant decreased exposure of normal tissue, is a contributing factor to the superior activity of C-55 versus C-52. However, except in the case of tumor tissue in which 81% of C-55 converts to C-52, only a minor amount of C-55 may serve as a prodrug for C-52, whereas the majority is handled by the biosystem through a different route of elimination. Tissue distribution combined with rate of conversion may be an important determinant of the relative effectiveness of other epoxide-chlorohydrin pairs of cryptophycins.
Reading Educational Philosophies in Freedom Writers

The 2007 film Freedom Writers portrays the real-life experiences of Erin Gruwell, a teacher at an inner-city high school in Long Beach, California. This article discusses the educational theories underpinning Gruwell's pedagogical practice, as seen in Freedom Writers, and identifies four themes—rewriting curriculum, treating students as creators of knowledge, creating classroom community, and teaching as self-realization—that make Gruwell's teaching successful.
Improved sparse spectrum model for the turbulent phase

Recently published Sparse-Spectrum (SS) model of the phase front perturbations by atmospheric turbulence1 is based on the trigonometric series with discrete random spectral support. SS model offers substantial computational savings, while preserving the wide range of scales typically associated with turbulence perturbations. We present an improved version of the SS model that accurately reproduces the power-law spectral density of the phase fluctuations in the arbitrary wide spectral band. SS model offers an ample flexibility in the choice of the probability distributions of the components wave vectors. The number of spectral components and the degree of probability distributions overlapping are the primary factors affecting the SS phase statistics. We use the Monte-Carlo model to examine the statistics of the SS phase samples for four basic versions of the SS model. We also present the calculations of the practically important long-exposure Strehl numbers. Non-overlapping SS model with log-uniform partition emerges as the most appropriate for the atmospheric turbulence representation. However, it is possible that the other model types can be used for optical propagation through different turbulent flows, such as air flows around domes and turrets, jets engine plumes, etc.
Trifluoromethyl Groups in Crystal Design of 1,4-Diphenyl-1,3-butadienes for Topochemical [2 + 2] Photodimerization

UV irradiation of the powdered crystalline sample of each of three (E,E)-1,4-di(trifluoromethyl-substituted)phenyl-1,3-butadienes (1−3) was found to yield a single [2 + 2] cycloaddition product in the solid state. Moreover, upon irradiation, the crystalline samples of two (E,E)-1,4-di(trifluoromethyl- and fluorine-substituted)phenyl-1,3-butadienes (4, 5) undergo a similar conversion to afford a [2 + 2] cycloaddition product, respectively. Our observations suggest that trifluoromethyl groups can be used to direct 1,4-diphenyl-1,3-butadiene molecules to form a parallel, offset-stacked orientation suitable for topochemical [2 + 2] cycloaddition.
Lack of a Direct Effect of 1,25-Dihydroxycholecalciferol on Parathyroid Hormone Secretion by Normal Bovine Parathyroid Glands

Because of differing reports of an effect of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] on parathyroid hormone (PTH) secretion, the present studies were perfomed in vitro using bovine parathyroid gland slices and isolated parathyroid cells. Both COOH-terminal and NH2-terminal RIAs for PTH were employed. No effect of 1,25(OH)2D3 on PTH secretion was found during a 4-h incubation of parathyroid slices in variable external calcium concentrations. The results from dual RIA measurements also showed no effect of 1,25(OH)2D3 on PTH secretion by isolated parathyroid cells during 90- to 150-min incubations with variable calcium concentrations. In addition, extensive analysis by polyacrylamide gel electrophoresis showed no effect of 1,25(OH)2D3 on cAMP generation. Whereas calcium inhibited and isoproterenol stimulated the production of cAMP, 1,25(OH)2D3 had no effect. We conclude that 1,25(OH)2D3 does not affect parathyroid gland function acutely in vitro.
Vortex Core Size in Submonolayer Superfluid 4He Films.

The superfluid transition of4He films adsorbed on 500 A diameter slip-cast alumina powder is measured with a torsion oscillator technique for films with transition temperatures between 50 and 700 mK. The transitions are found to be controlled by the universal Kosterlitz- Thouless critical line, but a strong increase in the broadening of the transition is observed for the thinnest films. Analysis in terms of vortex pair excitations shows that this broadening results from a vortex core size that increases rapidly as the film is thinned, scaling roughly with the interparticle spacing of the superfluid submonolayer. Third sound modes are identified in the dissipation, in addition to a broad peak from the vortex unbinding. This system provides evidence of a three-dimensional superfluid transition mediated by vortex excitations.
Triggers and mediators of hemorrhagic transformation in cerebral ischemia.

Intracerebral hemorrhagic transformation is a multifactorial phenomenon in which ischemic brain tissue converts into a hemorrhagic lesion with blood-vessel leakage, extravasation, and further brain injury. It has been estimated that up to 30–40% of all ischemic strokes undergo spontaneous hemorrhagic transformation, and this phenomenon may become even more prevalent with the increasing use of thrombolytic stroke therapy. An emerging conceptual model suggests that the loss of microvascular integrity and disruption of neurovascular homeostasis connects the experimental findings of blood-cell extravasation to brain injury after hemorrhage. In this short article, we examine mechanisms related to reperfusion injury and oxidative stress, leukocyte infiltration, vascular activation, and dysregulated extracellular proteolysis as potential triggers of hemorrhagic transformation. Perturbations in cell-cell and cell-matrix signaling within the hypothesized neurovascular unit may ultimately lead to neuroinflammation and apoptotic-like cell death in the parenchyma. Further investigations into the molecular mediators of hemorrhagic transformation may reveal new therapeutic targets for this clinically complex problem.
Effects of status epilepticus on hippocampal GABAA receptors are age-dependent

Long-term GABAA receptor alterations occur in hippocampal dentate granule neurons of rats that develop epilepsy after status epilepticus in adulthood. Hippocampal GABAA receptor expression undergoes marked reorganization during the postnatal period, however, and the effects of neonatal status epilepticus on subsequent GABAA receptor development are unknown. In the current study, we utilize single cell electrophysiology and antisense mRNA amplification to determine the effect of status-epilepticus induced by lithium-pilocarpine in postnatal day 10 rat pups on GABAA receptor subunit expression and function in hippocampal dentate granule neurons. We find that rats subjected to lithium-pilocarpine-induced status epilepticus at postnatal day 10 show long-term GABAA receptor changes including a two-fold increase in α1 subunit expression (compared with lithium-injected controls) and enhanced type I benzodiazepine augmentation that are opposite of those seen after status epilepticus in adulthood and may serve to enhance dentate gyrus inhibition. Further, unlike adult rats, postnatal day 10 rats subjected to status epilepticus do not become epileptic. These findings suggest age-dependent differences in the effects of status epilepticus on hippocampal GABAA receptors that could contribute to the selective resistance of the immature brain to epileptogenesis.
John Brown as guerrilla terrorist

John Brown is usually not considered to have been a terrorist, and even recent analyses of his activities consider him to be a guerrilla fighter or insurgent in his activities in Kansas. Brown, however, meets the criteria of a terrorist more than a guerrilla fighter when his activities in the Kansas Territory are considered. His raid on Harpers Ferry, however, is more in line with guerrilla operations or insurgent activities.
The Clipper Field, Blocks 48/19a, 48/19c, UK North Sea

Abstract The Clipper Gas Field is a moderate-sized faulted anticlinal trap located in Blocks 48/19a, 48/19c and 48/20a within the Sole Pit area of the southern North Sea Gas Basin. The reservoir is formed by the Lower Permian Leman Sandstone Formation, lying between truncated Westphalian Coal Measures and the Upper Permian evaporitic Zechstein Group which form source and seal respectively. Reservoir permeability is very low, mainly as a result of compaction and diagenesis which accompanied deep burial of the Sole Pit Trough, a sub basin within the main gas basin. The Leman Sandstone Formation is on average about 715 ft thick, laterally heterogeneous and zoned vertically with the best reservoir properties located in the middle of the formation. Porosity is fair with a field average of 11.1%. Matrix permeability, however, is less than one millidarcy on average. Well productivity depends on intersecting open natural fractures or permeable streaks within aeolian dune slipface sandstones. Field development started in 1988. 24 development wells have been drilled to date. Expected recoverable reserves are 753 BCF.
Design of a cellulose-based nanocomposite as a potential polymeric scaffold in tissue engineering

Abstract Cellulose-based nanocomposites could potentially function as structural materials for prosthetic vascular conduits given their moldability, mechanical strength in the wet state, stability, and durability as well as their ability to integrate a nanofibrous porous network with superior structural diversity and functional versatility. In this study, we have developed a cellulose-based nanocomposite consisting of cellulose nanowhiskers (CNWs) embedded and aligned in a cellulose acetate propionate (CAP) matrix. When compared to non-biocompatible inclusions such as carbon nanotubes and Kevlar fillers, CNWs imparted significant strength and directional rigidity to the CNW-CAP composite even at 0.2 wt.%. In addition, a significant improvement in critical properties was observed when the CNWs were aligned in an externally-applied relatively weak magnetic field (0.3 T). Magnetically induced alignment not only improved the directionality and percolation limits of the nanoparticles within the medium, but also drastically lowered the optimum amount of CNWs required to obtain the best composite performance. Therefore, highly desirable properties can be induced in cellulose-based biocompatible composites by modifying the processing methods, with potential use as scaffolds for vascular tissue engineering of a small diameter graft.
The identification of a Caenorhabditis elegans homolog of p34cdc2 kinase.

We have identified a Caenorhabditis elegans homolog of p34cdc2 kinase. The C. elegans homolog, ncc-1, is ∼-60% identical to p34cdc2 of Homo sapiens. When expressed from a constitutive yeast promoter, ncc-1 is capable of complementing a conditional lethal mutation in the CDC28 gene of Saccharomyces cerevisiae, indicating that this C. elegans homolog can properly regulate the cell cycle.
Modeling of nitric oxide formation in high-pressure premixed laminar ethane flames

The GRIMECH version 2.11 chemical kinetics mechanism is modified to provide improved predictions of NO concentrations in high-pressure (1 < P < 15), low-temperature (1600 K–1850 K), premixed, flat, laminar, C2H6/O2/N2 flames. The modifications include adding 38 reactions to expand the C2 submechanism and using different reaction rate coefficients for the CH + N2 ↔ HCN + N reaction. The unmodified GRIMECH mechanism significantly underpredicts the NO concentrations in rich flames. In addition, the predictions from the original mechanism are poor qualitatively, particularly at the lower pressures studied. As the prompt-NO mechanism has been shown to be significant in the rich flames in this study, it is expected that the predictive errors of the unmodified mechanism are a result of deficiencies in the modeling surrounding the prompt-NO formation pathway. To account for the underprediction of prompt-NO, a different set of proposed reaction rate coefficients for the CH + N2 ↔ HCN + N are used in the revised model. The expansion of the C2 submechanism reactions enhances the existing C2 chemistry in the original mechanism, which was designed primarily for methane combustion. The modified mechanism provides good agreement with published NO concentration data from the postflame regions of flames from 1 to 9.16 atm. The revised mechanism does continue to underpredict the NO concentrations in 14.6-atm flames, although the predictions are improved qualitatively from the original mechanism at that pressure.
Evoked pre- and post-synaptic activity in the optic tectum of the cannulated tadpole.

We describe the cannulated Rana pipiens, tadpole preparation that allows for stable recording in the tectum of the extracellular potential elicited by optic nerve stimulation. The largest components of the evoked tectal response consist of two previously identified waves and a major third, long-latency wave of long duration. These components were reversibly eleminated by perfusion of high magnesium/no calcium Ringer's solution or Ringer's solution containing cobalt chloride. In contrast, perfusion of high calcium/no magnesium Ringer's increased the amplitude and area of these components. We conclude that these components represent post-synaptic activity.
The structure of the capsular polysaccharide from crytococcus neoformans serotype d

Abstract The capsular polysaccharide from Cryptococcus neoformans serotype d has been studied by employing the usual methods for the elucidation of chemical structure. The results are consistent with the occurrence ofa polysaccharide having both d -glucosyl-uronic acid and d -xylosyl groups present as nonreducing end-groups attached to O-2 of d -mannosyl residues which are linked α- d -(1 → 3) in a linear backbone.
Problems with Gauge Invariance in Lorentz-Violating QED

We consider the radiative generation of a Chern-Simons addition to the effective action for a Lorentz-violating modification of electrodynamics. The coefficient of the induced Chern-Simons term is manifestly finite, but also potentially indeterminate. However, several values have been suggested as having special significance. We discuss two such special values, and it turns out that neither of them can be made consistent with the gauge invariance properties of the theory.
The Modularity Issue in Language Acquisition: A Rapprochement? Comments on Gallistel and Chomsky.

Chomsky (in this issue) and Gallistel (in this issue) review work on human language and on spatial cognition in animals, arguing that these skills are each supported by a specialized cognitive module with its own unique organization principles, different in kind from other aspects of cognition. In this commentary, I outline a contrasting non-modular (or semi-modular) view of human language and suggest that such an alternative is consistent with the arguments made by Chomsky and Gallistel and is equally plausible, given our present state of knowledge; and I suggest several directions for future research that are needed to determine which of the alternatives provides a better account of the architecture of high level cognition.
Flow structure in the near-field of buoyant low-density gas jets

Abstract Flow structure of helium jets injected into quiescent air was investigated numerically using finite volume approach. The analysis is based on unsteady, laminar, axisymmetric, isothermal flow in a binary fluid system. The jet Reynolds number, Re was varied from 40 to 150 to encompass steady and oscillating jet flow regimes. Comparison with experimental data revealed excellent agreement, proving reliability of the model in predicting global flow characteristics. At low jet Reynolds numbers, the flow was steady and the concentration shear layer at the tube exit was stratified by mixing between jet and ambient fluids inside the tube. At higher jet Reynolds numbers (Re = 90 and 150), buoyancy induced acceleration contracted the jet core to form a toroidal vortex by entrainment of the ambient fluid. Structural details of the globally unstable flow are discussed using instantaneous, mean and RMS profiles of helium concentration and axial velocity.
On the Search for Talent in Academic Labor Markets: Easily Observable Later-Graduate Study Outcomes as Predictors of Early-Career Publishing, Placement, and Tenure

Three easily observed later-graduate study outcomes, working with a prominent advisor, publishing while in graduate school, and coauthoring with the advisor are demonstrated to be significant determinants of early-career publishing success for a sample of nearly 3,000 Ph.D. recipients from more than 100 domestic programs between 1990 and 1993. Out-of-sample predictions for 681 Ph.D. recipients from the class of 1994 indicate that these easily observed later-graduate study signals dramatically improve our ability to forecast which students become prolific and which students fail to publish more than one article. Analyzing initial domestic tenure-track economics placements indicates that hiring departments placed far more emphasis on Ph.D. program pedigree, leading to an initial tenure rate of less than 50% but eventually nearly three-fourths currently hold tenured positions in the United States. (JEL J24, J44)
Morphology and ultrastructure of anterior thalamic neurons solidly labeled with horseradish peroxidase

Abstract ‘Golgi-like’ labeling of anterior thalamic neurons was achieved by injecting horseradish peroxidase dissolved in dimethylsulfoxide (DMSO) into the striatum of the rabbit. Forty-eight hours after injection, elements of the presumed thalamocortical population of anterior thalamic neurons are diffusely filled with HRP to the extent that their dendritic arborizations, and even spinous processes, can be readily characterized. Ultrastructurally, these solidly labeled thalamic neurons are seen to contain large, irregular electron dense granules dispersed within a moderately electron dense cytoplasm.
The threshold value of a quality index for formation of cellular manufacturing systems

The superiority of cellular manufacturing to job shop manufacturing has been questioned by a number of simulation studies. The initial structure of the machine-part matrix seems to play an important role in the failure of cellular manufacturing systems in these studies. In this paper a grouping measure called ‘quality index— QI’ will be used to evaluate the relationship between the quality of a machine-part matrix and the performance of the corresponding cellular manufacturing system. A simulation study will be conducted to demonstrate how the procedure can be used to determine the threshold value for QI beyond which the cellular manufacturing system outperforms the corresponding job shop manufacturing system.
Automated analysis of embryonic gene expression with cellular resolution in C. elegans.

Automated imaging of the Caenorhabditis elegans embryo now allows monitoring of the timing and relative expression of individual reporter genes at single-cell resolution over almost all of embryonic development. Future systematic analysis could be used to reveal gene expression patterns of every cell during development. We describe a system that permits the automated analysis of reporter gene expression in Caenorhabditis elegans with cellular resolution continuously during embryogenesis. We demonstrate its utility by defining the expression patterns of reporters for several embryonically expressed transcription factors. The invariant cell lineage permits the automated alignment of multiple expression profiles, allowing direct comparison of the expression of different genes' reporters. We also used this system to monitor perturbations to normal development involving changes both in cell-division timing and in cell fate. Systematic application of this system could reveal the gene activity of each cell throughout development.