cssi/SciSciGPT-SciSciNet huggingface dataset:
Radiovoltaics: High-efficiency conversion of ionizing radiation directly to electrical power

Radiovoltaic devices can directly convert high-energy β-electron or a-particle emissions from radioisotopes to electrical power through the generation and separation of electron hole pairs in semiconductors. By carefully matching length scales involved in the physics of absorbing high-energy electrons in semiconductors and the diffusion lengths of electrons and holes, it is possible to increase the power conversion efficiency. This paper demonstrates a distinct increase in conversion efficiency in p-i-n diodes compared to pn diodes.
Chapter 12 Band Structure of the Group III Nitrides

Publisher Summary This chapter describes the current state of knowledge of the electronic band structure of group III nitrides, as well as some historic perspective. The number of papers dealing with the electronic band structure of the nitrides and the variety of methods applied may seem bewildering to the nonexpert. Many of these are only slight variations on a theme, and most recent calculations agree with each other on the basic aspects. The chapter also considers the band structures, mostly at the scale of several eV. For most of the intended applications of the nitrides, the most important part of the band structure, however, is the region right next to the band edges, at a scale of meV. This pertains to questions on the effective masses, exciton splittings under strain, etc. The intrinsic ambiguities in the semi-empirical pseudopotential method have left much uncertainty on even elementary questions on the band structures, such as whether the nature of the gap is direct or indirect.
Monotonic Language Learning

Learnability of families of recursive languages from positive data is studied in the Gold paradigm of inductive inference, where the learner obeys certain constraints motivated by work in inductive reasoning. Previously, various notions of monotonicity have been defined in the context of language learning. These constraints require that the learner's guess monotonically ‘improves’ with regard to the target language. In this paper, the ideas from inductive reasoning are instantiated in alternative ways. Links are established between the various new constraints both among themselves as well as with other well-known constraints, such as conservativeness. Exactly learnable families are characterized for prudent learners which obey various combinations of these constraints. Applications of these characterizations are also shown.
Thucydides and the Invention of Political Science

Thucydides self-consciously invented a new form of inquiry, which can reasonably be called “social and political science.” His intellectual goal was a new understanding of power and its relationship to human agency and the deep structures of human society. His understanding of agency and structure is in some ways reminiscent of the reflexivity theory developed by Anthony Giddens.
When it's hip to be square

Most animals and plants approximate a cylinder in shape, and where junctions occur (as with branches of trees or limbs on animals), those corners are “faired,” meaning smoothly curved so that one surface grades into the next ( 1 ). When living organisms deviate from the norm, there's usually a good biomechanical reason: a clue to some specific problem that needs to be solved. Among their suite of unusual characteristics, seahorses possess a true oddity: a prehensile tail with a square, rather than round or elliptical, cross-sectional shape. On page [10.1126/science.aaa6683][1] of this issue, Porter et al. ( 2 ) report that there are distinct mechanical advantages to being square. Using three-dimensional (3D) printing to construct physical models, the team demonstrates that the multiplated anatomy of the square seahorse tail shows greater resistance to mechanical deformation than a similar model that has a round cross section. [1]: /lookup/doi/10.1126/science.aaa6683
Second-Order Γ-limit for the Cahn–Hilliard Functional

The goal of this paper is to solve a long standing open problem, namely, the asymptotic development of order 2 by Γ-convergence of the mass-constrained Cahn–Hilliard functional.
Leaching aluminum — superalloy melts with hydrochloric and sulfuric acids

Abstract The Bureau of Mines investigated a method for increasing the leaching rate of bulk superalloy scrap to facilitate recycling and recovery of critical metals such as Ni, Co and Cr. Superalloys were melted with 20, 30, 40 and 50% Al to form intermetallic compounds. The melts were easily crushed to a convenient particle size and leached rapidly with hydrochloric and sulfuric acid solutions. Leaching 1 2 - in . pieces of scrap IN-738 with excess 6 N HCl at 95 °C for 2 h resulted in only 0.5% dissolution, whereas leaching 10 g of minus 20-mesh 3001o Al-70 pct IN-738 with excess 6N HCl at 95°C for 2 h achieved a 96.2% dissolution.
Neurochemical Characterization of Extracellular Serotonin in the Rostral Ventromedial Medulla and Its Modulation by Noxious Stimuli

Using in vivo microdialysis, we have characterized serotonin release from the rostral ventromedial medulla of the freely moving rat. Addition of tetrodotoxin or removal of calcium from the dialysis solution diminished the dialysate serotonin content, suggesting that spontaneous, calcium channel- and sodium channel-dependent neuronal release mechanisms contribute to the extracellular serotonin collected from the rostral ventromedial medulla. Extracellular serotonin concentration was increased by depolarization (with 100 mM potassium) and by the local administration of either a reuptake blocker (citalopram), a monoamine oxidase inhibitor (pargyline), or amphetamine. Serotonin release was reduced significantly by 8-hydroxy-2-(di-n-propylamino)tetralin, suggesting that serotonin1A receptors may regulate release from rostral ventromedial medulla neurons. Because the basal serotonin concentration in the rostral ventromedial medulla was approximately twofold higher than that collected from the rostral ventrolateral medulla, a region that contains serotonin terminals but many fewer cell bodies, the possibility of release of serotonin from rostral ventromedial medulla neurons is discussed. Finally, intraplantar formalin injection significantly increased serotonin release, suggesting that this neurotransmitter contributes to nociceptive modulation by regulating the outflow of the rostral ventromedial medulla neurons.
252Cf plasma desorption mass spectrometry. Contributions from the rockefeller university

Abstract The paper describes a selection of contributions made by members of Professor Frank H. Field's group in The Rockefeller University Mass Spectrometry Laboratory to both fundamental and applied aspects of 252 Cf plasma desorption mass spectrometry.
Future employment promises as rent seeking in representative government

Researchers of legislative behavior have attempted to explain the decisions of legislators for some time. Public choice scholars have argued that legislators will “sell” political favors in exchange for some from of interest group payment that is thought to benefit the legislator's electoral ambitions. Yet, legislators do not appear to receive the full value of their political favor in these exchanges. That is, the value of the policies offered appears to exceed the price paid by interest groups in the form of campaign contributions, speaking honoraria and other material payments. This imbalance has led some scholars to discount theories that explain legislative behavior motivated by material gain. However, to the extent that legislators value post‐elective employment opportunities, interest groups have an incentive to use the offer of future employment as a payment for present legislative influence. In this sense, perhaps a large portion of the difference in payments can be accounted for in the post‐elective employment careers of elected politicians. In this paper, I explore and explain this theory using a political market model and attempt to identify several attributes that I believe will be common among “prospect‐legislators” whose behavior is principally motivated by concerns with post‐elective life.
Inhibition of liver,kidney, and erythrocyte δ-aminolevulinic acid dehydratase (porphobilinogen synthase) by gallium in the rat

Selective inhibition of enzymes in the heme biosynthesis pathway with concomitant urinary excretion of heme precursors serve as potentially important biological markers of chemical exposure and cell injury. Intratracheal administration of gallium arsenide particulate suspensions has been shown to result in inhibition of delta-aminolevulinic acid dehydratase (ALAD) in several tissues and increased excretion of the heme precursor aminolevulinic acid (ALA). This study was undertaken to evaluate in vivo the role of gallium alone in ALAD inhibition and increased urinary excretion of ALA. Male CD rats received a single ip injection of Ga2(SO4)3 at doses of 12.5, 25, 50, 100, and 200 mg Ga/kg. A dose-dependent inhibition of ALAD was observed 24 hr later in liver, kidney, and erythrocytes. After injection of 25 mg Ga/kg, maximal inhibition (42 to 49% of control) of ALAD occurred between 6 and 24 hr in liver and kidney with full recovery of activity at 96 hr. In erythrocytes, maximal inhibition (48% of control) occurred between 24 and 48 hr with recovery of activity at 96 hr. Mild to moderate renal proximal tubular necrosis in the pars recta was observed 24 hr after administration of 100 and 200 mg/kg, but no histopathologic changes were evident at lower doses. No consistent changes in urinary excretion of ALA were observed. Lineweaver-Burk analyses of renal and hepatic ALAD activities in the absence and presence of gallium indicated that the inhibition of ALAD by this element is noncompetitive (same Km, decreased Vmax). Gallium was shown to possess an inhibition constant (Ki) of approximately 3 microns for ALAD, similar to the Ki obtained for lead in other studies. Incubation of ALAD in vitro with gallium and lead, an active thiol group inhibitor, resulted in a greater inhibition of the enzyme. Further in vitro studies demonstrated the attenuation of gallium inhibition of hepatic and renal ALAD by zinc, suggesting that the mechanism of gallium action may involve competition for or displacement of zinc from the sulfhydryl group of the enzyme active site. Since ALAD inhibition occurred at doses at which no histopathologic changes were evident, the determination of ALAD activity in various tissues, including blood, may be of potential value as a biomarker of exposure/toxicity to metals such as gallium. The effect of chemical form and route of exposure of gallium and effects of other Group III metals on inhibition of ALAD and excretion of ALA is discussed.(ABSTRACT TRUNCATED AT 250 WORDS)
Bioengineered muscle constructs and tissue-based therapy for cardiac disease

Abstract Bioengineering of contractile muscle tissues and organs for disease treatment is currently in the preclinical experimental stage of development. Cell biology over the last several decades has primarily focused on breaking down tissues and cells to smaller and smaller components to understand their functioning at the molecular level. We are just beginning to understand how to reassemble these components back into larger functional units. The merging of the fields of traditional engineering, biomaterials, cell biology, and computer science will lead to the ex vivo engineering tissues and organs for many cardiovascular applications in the future. For pediatric cardiology, bioengineered contractile tissues may serve as force generating cardiac patches, heart valve papillary muscle substitutes, or as living therapeutic protein delivery ‘devices’ when bioengineered from genetically engineered muscle cells.
Life and politics as plural: James and Bentley on the twentieth century problem

If twentieth century thought has been characterized by a preoccupation with the themes of analysis, fragmentation, specialization, alienation and anomie, American speculation on the disunity of the cosmos has owed a great debt to the metaphysics and psychology of William James and the political theory of Arthur F. Bentley. While James revolted against idealistic holism by describing a "pluralistic universe" and an empirical self constituted by disparate processes, Bentley reacted against a political science of state and sovereignty by developing a doctrine of political pluralism based on the activity of interest groups. The division of the whole into its separate, and often unrelated, constituents was carried out in America in the name of pluralism. Though Europeans might despair about dissolution and estrangement, American pragmatists and behaviorists revelled in their new freedom from the "block universe." The destruction of monism could be interpreted as the final step in the liberation of America from the Old World. With optimism and confidence James used the political analogy of a federal republic to elucidate his pluralistic metaphysics, t Bentley, a self-conscious disciple of James, improved upon his master by dissecting the "federal republic" itself. No pessimist, he praised the Jamesian approach: "No one has made a more brilliant raid into the social field than James in his analysis of the 'selves.' " e Karl Jaspers has remarked that while pragmatism "seemed to be laying new foundations" for existence-philosophy, "what it built thereon was nothing more than an aggregate of crude analysis of life and cheap optimism, was a mere expression of a blind confidence in the extant confusion." 3 Why, when others were attempting to reconstruct unity of purpose, did philosophers like James and Bentley embrace a purposeless diversity? Did they discover something worthwhile in twentieth century life and politics to which Europeans were blinded and which contemporary Americans have lost? James was one of the first writers to adopt a fully pluralistic view of government and politics. In The Varieties of Religious Experience he noted that no major social institution could be defined simply. This was particularly
Degradation in short wavelength (AlGa)As light-emitting diodes

Degradation in short-wavelength (AlGa)As lasers is investigated through lifetests of such devices operated in the incoherent mode. It is shown that degradation increases with emission energy for diodes containing zinc in the p-type (AlGa)As bounding region, whereas diodes containing Ge in this region, although not satisfactory as c.w. lasers because of high resistivity, show no degradation. A way out of this difficulty is proposed through double doping with Ge and Zn, in which case degradation appears to be brought down to the Ge level.
Musicians' and Nonmusicians' Assessment of Perceived Rubato in Musical Performance:

The purpose of this study was to investigate musicians' and nonmusicians' assessment of perceived rubato in musical performance. Music majors (n = 48) and nonmusic majors (n = 48) listened to four different soloists' performances of the development section of Mozart's Concerto for Horn and Orchestra No. 2, movement 1. Subjects evaluated the degree of appropriateness/inappropriateness of each soloist's use of rubato using the Continuous Response Digital Interface (CRDI), an instrument that allows ongoing evaluation of specified performance variables. Using a Likert-type scale, subjects also assessed soloists with regard to musicianship, expression, tone quality, and tempo. Results indicated significant differences for musicians compared to nonmusicians regarding rubato assessments. Musicians agreed with expert assessments, whereas non-musicians' scores seemed haphazard. When musicians were separated into two groups based on musical skill level, results from the “more proficient” musicians were in direct ag...
Errors in spatial phase-stepping techniques

Spatial phase-measurement interferometry techniques are affected by a number of sources of error. This paper focuses on the major limitations for phase calculations using standard N- point algorithms. These limitations are having the wrong carrier frequency, unequally spaced fringes, detector nonlinearities, and variations in the dc fringe intensity. Computer simulations reveal the character and magnitude of these errors.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Emissions from and within an Allison J-33 Combustor

Abstract Gas temperature, carbon monoxide, and nitric oxide concentration profiles measured as a function of axial and radial position inside an Allison J-33 combustor with unheated inlet air are reported. In addition, the isolated effects of combustor pressure, overall equivalence ratio, and air flow rate on combustor exit plane emissions are investigated. A consistent model of the combustion process in this combustor is presented on the basis of the results.
Thermally activated amorphous phase formation in cold-rolled multilayers of Al–Ni, Al–Ta, Al–Fe and Zr–Cu

Abstract Intermixed structures of different binary systems (Al 80 Ni 20 , Al 75 Ta 25 , Al 75 Fe 25 and Zr 67 Cu 33 ) were prepared by repeated cold rolling with intermediate folding of elemental foils. The microstructural development during the rolling procedure and after annealing were measured by X-ray diffraction, scanning and transmission electron microscopy. While the rolling procedure yielded mostly nanometer sized crystalline (nanocrystalline) morphologies, amorphous regions were formed in all investigated samples after thermal exposure of the samples under argon atmosphere at temperatures between 560°C and 1400°C. The amorphous phases are formed in localized sample regions of up to 20 μm in size which had local oxygen levels between 10 and 40 at.%. While amorphous areas of an Al 80 Ni 20 sample crystallized on heating in the beam of a transmission electron microscope with rejection of oxygen, thicker amorphous regions were unaffected by this thermal treatment. The thermal stability of the amorphous regions together with the observation of the in situ crystallization of thinner sample areas indicate that the oxygen content acts to stabilize the amorphous phase and prevents the growth of intermetallic crystals.
Two Posttranscriptional Pathways That Regulate p21Cip1/Waf1/Sdi1Are Identified by HPV16-E6 Interaction and Correlate with Life Span and Cellular Senescence

The p21(Cip1/Waf1/Sdi1)protein is a cyclin-dependent kinase inhibitor that is induced in normal human fibroblasts (NHF) following DNA damage, following serum stimulation, and at cellular senescence. Expression of the human papilloma virus 16 E6 oncoprotein in NHF cells results in the loss of the p21 protein, independent of mRNA level under most conditions. The p21 protein levels in NHF-E6 cells remained low following DNA damage or serum stimulation even though mRNA levels increased. In contrast, the p21 protein was transiently induced in NHF-E6 cells at the onset of cellular senescence. Expression of the E6 oncoprotein in transformed cells had no effect on p21 protein levels. This demonstrates that two posttranscriptional pathways regulate expression of p21 protein in NHF cells under different conditions. Disruption of posttranscriptional regulation is correlated with extension of life span, altered cell fate, and transformation.
Paper 5: Power Assistance Pumps for Steering

This paper discusses the pump output problems peculiar to power assisted steering, together with the need for the flow control valve. A description of a basic combined flow control and pressure relief valve is given, and the adaptation of the flow control valve to the requirements of power assisted steering is detailed. The pump construction and operation are mentioned, with a description of a typical pump with reference to the special features incorporated for quiet operation. Some changes in design, in an attempt to keep pace with higher pressure demands, are described. The paper also presents the various types of installations and measures adopted to minimize transmitted noise, and concludes with a brief survey of pump types.
Concurrent Finger-Tapping in Mathematically Gifted Males: Evidence for Enhanced Right Hemisphere Involvement During Linguistic Processing

O'Boyle and Benbow (1990) have suggested that enhanced involvement of the right hemisphere (RH) during basic information processing is a neuropsychologic characteristic of the gifted brain. To provide converging evidence for this hypothesis, the present study was conducted using a concurrent finger-tapping paradigm. Specifically, 24 mathematically precocious and 16 average ability adolescent males were required to tap a key as quickly as possible while sitting silently (baseline condition), concurrently reading a paragraph aloud (verbal load), or encoding a random form into memory (spatial load). For average ability subjects, the concurrent verbal load reduced tapping rate for the right but not the left hand, reflecting a division of LH resources between linguistic processing of the paragraph and motor control of the contralateral hand. In contrast, for gifted subjects, both their left- and right-hand tapping rates were significantly reduced, suggesting that both hemispheres were engaged during verbal processing. The concurrent spatial task produced a small but reliable reduction in finger-tapping rate for both the left and right hand in each group. These findings provide additional support for the notion that enhanced reliance on RH functioning is a physiological correlate of mathematical precocity in gifted males.
Genetic Variants in the FADS Gene: Implications for Dietary Recommendations for Fatty Acid Intake

Unequivocally, genetic variants within the fatty acid desaturase (FADS) cluster are determinants of long chain polyunsaturated fatty acid (LC-PUFA) levels in circulation, cells and tissues. A recent series of papers have addressed these associations in the context of ancestry; evidence clearly supports that the associations are robust to ethnicity. However ∼80% of African Americans carry two copies of the alleles associated with increased levels of arachidonic acid, compared to only ∼45% of European Americans raising important questions of whether gene-PUFA interactions induced by a modern western diet are differentially driving the risk of diseases of inflammation in diverse populations, and are these interactions leading to health disparities. We highlight an important aspect thus far missing in the debate regarding dietary recommendations; we content that current evidence from genetics strongly suggest that an individual's, or at the very least the population from which an individual is sampled, genetic architecture must be factored into dietary recommendations currently in place.
Infection of polarized MDCK cells with herpes simplex virus 1: two asymmetrically distributed cell receptors interact with different viral proteins.

Abstract Herpes simplex virus 1 attaches to at least two cell surface receptors. In polarized epithelial (Madin-Darby canine kidney; MDCK) cells one receptor is located in the apical surface and attachment to the cells requires the presence of glycoprotein C in the virus. The second receptor is located in the basal surface and does not require the presence of glycoprotein C. Exposure of MDCK cells at either the apical or basal surface to wild-type virus yields plaques and viral products whereas infection by a glycoprotein C-negative mutant yields identical results only after exposure of MDCK cells to virus at the basal surface. Multiple receptors for viral entry into cells expand the host range of the virus. The observation that glycoprotein C-negative mutants are infectious in many nonpolarized cell lines suggests that cells in culture may express more than one receptor and explains why genes that specify the viral proteins that recognize redundant receptors, like glycoprotein C, are expendable.
Dynamic visible interferometric measurement of thermal fields around living biological objects

Dynamic interferometry is a highly sensitive means of obtaining phase information that can determine phase at rates of a few measurements per second. The sensitivity of these phase-measurement instruments is on the order of thousandths of a wavelength at visible wavelengths enabling the measurement of small temperature changes and thermal fields surrounding living biological objects. Temperature differences are clearly noticeable using a visible wavelength source because of subtle changes in the refractive index of air due to thermal variations between an object and the ambient room temperature. Living objects can also easily be measured over a period of time to monitor changes as a function of time. This technique has many promising applications in biological and medical sciences for studying thermal fields around living objects. In this paper we compare differences in thermal fields measured with dynamic phase-measuring interferometry surrounding room temperature and body temperature inanimate objects as well as living biological objects at data rates of many measurements per second.
Simple devices for sterile aeration and mixing in NMR cell metabolism studies

In the past, difficulty in performing plant and animal cell metabolism studies in NMR samples has often been experienced. Thus, without continuous agitation, cell aggregations formed, leading to inhomogeneous mixtures which excluded the substrate, thereby vitiating kinetic analysis of the experiments. Again, contamination by foreign microorganisms (which in most instances proved to be more vigorous in replication and metabolism than the cells of interest) also occurred. Early attempts to use gases bubbled from the bottom of the sample tube as a mixing device were partially successful but bubbles in the sampling volume seriously degraded field homogeneity and further added to contamination problems. Santos and Turner (1) have described a system which used bubbles rising in an open-ended inner tube to pump the culture, thus overcoming the mixing problems without degrading field homogeneity. A later, somewhat more complicated design based on the same principles has been presented by Boume (2). We have recently modified the design for 10 and 5 mm sample tubes and have also prevented contamination of the initially sterile incubation mixtures by constant flushing with gases which have passed through 0.1 grn filters, the tube itself being maintained at slight positive pressure. The 10 and 5 mm pumping devices as shown in Figs. 1 and 2, respectively, have been successfully utilized in studies in which human breast cancer cell metabolism is followed over 12 hour periods. However, on attempting to use these designs with plant callus cell cultures which are much heavier and more viscous than cancer cells or other mammalian and bacterial cells, we found that the pumping action provided by bubbling was insufficient to prevent cell clumping. Attempts to solve this problem by changing inner tube dimensions, bubble size and rate, and sample tube diameter were unsuccessful. A more powerful agitation system was needed, and we therefore developed the mechanically stirred mixing and aerating system shown in Fig. 3, which uses the normal NMR sample spinner operating at approximately 15 cps as energy source, so that the sample solution is spun over a stationary propeller producing vigorous mixing. This system is somewhat more difficult to sterilize, but we find that, with care, contamination problems are not encountered. The filter and Teflon needle are attached to the Teflon rod above the sample tube cap with tape. Efficient mixing and aeration of plant callus cell cultures with this system was achieved, and samples which had previously died within an hour were stable for days. Our original design utilizes a copper stirrer blade which could be replaced by a blade made of Teflon or glass. This proved unnecessary for the 20 mm sample tube stirrer, however, since no significant problems with sample
Alternative Heterocycles for DNA Recognition: The Benzimidazole/Imidazole Pair

Boc-protected benzimidazole-pyrrole, benzimidazole-imidazole, and benzimidazole-methoxypyrrole amino acids were synthesized and incorporated into DNA binding polyamides, comprised of N-methyl pyrrole and N-methyl imidazole amino acids, by means of solid-phase synthesis on an oxime resin. These hairpin polyamides were designed to determine the DNA recognition profile of a side-by-side benzimidazole/imidazole pair for the designated six base pair recognition sequence. Equilibrium association constants of the polyamide-DNA complexes were determined at two of the six base pair positions of the recognition sequence by quantitative DNase I footprinting titrations on DNA fragments each containing matched and single base pair mismatched binding sites. The results indicate that the benzimidazole-heterocycle building blocks can replace pyrrole-pyrrole, pyrrole-imidazole, and pyrrole-hydroxypyrrole constructs while retaining relative site specifities and subnanomolar match site affinities. The benzimidazole-containing hairpin polyamides represent a novel class of DNA binding ligands featuring tunable target recognition sequences combined with the favorable properties of the benzimidazole type DNA minor groove binders.
There is more to typesetting than setting type

Some typographic conventions relating to line composition and page makeup are presented in the context of the problems they pose to the designer of a computer program for typographic composition.
Kinetic Isotope Effects in the Chromium(VI) Oxidation of Bicyclic Alcohols

Pseudo first-order rate constants are determined for the oxidation of a series of secondary alcohols and their monodeutero analogues by ammonium chromate in aqueous acidic solution at several temperatures; the relative rates and activation parameters are consistent with a cyclic, symmetrical transition state.
The impact of attentional, auditory, and combined cues on walking during single and cognitive dual tasks in Parkinson disease.

Abstract Auditory and attentional cues improve gait in Parkinson disease (PD), but it is unclear if combining the two cueing strategies offers additional benefit. Further, the effect of a secondary cognitive task on cue efficacy is unknown. Therefore, this study aimed to assess the effects of cue type and task complexity on gait in PD. 11 participants with PD, 11 age-matched controls, and 11 young controls performed 3 walking trials on a GAITRite walkway under the following cueing conditions: no cue (baseline), rhythmic auditory cue at 10% below (AUD−10) and 10% above (AUD+10) self selected cadence, attentional cue (ATT; “take long strides”), and a combination of AUD and ATT (COM−10, COM+10). Each condition was also performed concurrently with a secondary word generation task (dual task, DT). Baseline gait velocity and stride length were less for those with PD and age-matched controls compared to young controls, and the ability of those with PD to use cues differed from the other groups. Gait velocity and stride length increased in PD with ATT, but not with auditory cues. Similar increases in gait velocity and stride length were observed with the combined cues, but additional benefit beyond ATT alone was not observed. Cues did not improve gait velocity during dual task walking, although stride length did increase with COMB+10. It appears persons with PD are able to benefit from attentional cueing and can combine attentional and auditory cues, but do not gain additional benefit from such a combination. During walking while performing a secondary cognitive task, attentional cues may help to facilitate a longer stride length.
APC-dependent regulation of ornithine decarboxylase in human colon tumor cells.

Mutation/deletion of the adenomatous polyposis coli (APC) tumor suppressor gene in germline cells of rodents and humans is associated with increased intestinal activity of ornithine decarboxylase (ODC), the first enzyme in polyamine synthesis, and intestinal neoplasia. To study the role of APC in signaling ODC expression, we used the human colon tumor cell line HT29 (wtAPC−/−), which has been stably transfected with a zinc-inducible wild-type APC gene. The addition of ZnCl2 to HT29-APC cells increased wild-type APC protein and Mad1 RNA and protein and decreased levels of c-myc and ODC RNA and protein, relative to these parameters in HT29 cells transfected with the same plasmid containing the β-galactosidase gene in place of APC. Upon induction of APC expression, ODC promoter activity and RNA levels were suppressed. When the e-box domain in the 5′ flanking region of the ODC gene was mutated, ODC promoter activity was unaffected by wild-type APC expression. Antisense, but not missense, c-myc oligonucleotides decreased ODC activity in HT29 cells expressing mutant APC. These results demonstrated that wild-type APC suppressed c-myc and activated Mad1 expression in HT29 colon-derived cells. These proteins, in turn, regulated the transcription of target genes, including ODC. The data presented indicate that ODC is a modifier of APC-dependent signaling in intestinal cells and tissues. © 2002 Wiley-Liss, Inc.
Solubilization and Electrophoretic Characterization of the Great Northern Bean (Phaseolus vulgaris L.) Proteins

Protein content of dry beans (Phaseiolus vulguris L.) cultivar Great Northern, was 26.10% (dry weight basis). The isoelectirc pH of the NaCl extractable proteins was about 4.4. Several salts, NaOH, and HCl were employed to solubilize the Great Northern bean proteins. Amongst all the protein solubilizing agents, Na2CO3, K2SO4, sodium dodecyl sulfate (SDS), and NaOH at respective concentrations of 0.5, 5, 5% (all w/v), and 0.02N were found to be better protein solubilizers than the rest; solubilizing 93.6g of Lowry protein per 100g of Kjeldahl protein. Albumins and globulins accounted for 21.18 and 73.40% respectively, of the total bean proteins. Protein content of albumins, globulins, protein concentrates, and protein isolates was 81.68, 92.26, 85.44, and 92.43% (dry weight basis) respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the bean flour, albumins, globulins, protein concentrates, and protein isolates revealed the presence of 22, 14, 10, 14, and 11 subunits, respectively. The bean flour, albumin's, globulins, protein concentrates and protein isolates were characterized by the predominance of subunits with apparent molecular weights of 294,000, 266,000, 123,000, 146,000, and 135,000 daltons, respectively. Isoelectric focusing of the bean flour, albumins, globulins, protein concentrates, and protein isolates indicated 15, 13, 15, 16, and 11 subunits, respectively. Molecular sieve chromatography of the bean flour proteins, albumins, and globulins followed by SDS-PAGE was also employed to study the complexities of these proteins.
Quantitative restrictions and the welfare effects of capital inflows

Abstract This paper explores the welfare effects of capital inflows when some imports are subject to quantitative restrictions. It is shown that in a Heckscher-Ohlin model where all imports are restricted by quotas and some fraction of the initial domestic capital stock is foreign owned, a capital inflow is welfare improving regardless of the ranking of sectoral factor intensities. With sector-specific capital stocks and both tariff-ridden and quota restricted imports, the consequences of direct foreign investment in any sector are uncertain and depend upon whether the two imports are compensated substitutes or complements as well as the characteristics of production.
Queueing network model for a class of material-handling systems

A queueing network-based approximation model was developed to evaluate the performance of a fixed-route material-handling system supporting a multiple-workcentre manufacturing facility. The closest transporter allocation scheme was used to assign empty transporters to jobs needing to be moved between various workcentres. This control methodology creates two interesting difficulties that require solving for an accurate approximation model. A model of the distributions of the location of an assigned transporter as a function of the number of available transporters is developed. In addition, it is shown that owing to the strong dependent service time aspect of this situation, the standard queueing network decomposition approach of treating the material-handling systems as a GI/G/c queue can be highly inaccurate. Thus, it is necessary to develop a dependent service-time model for approximating the queueing delay encountered while waiting for an empty transporter assignment.
Cell-killing potential of a water-soluble radical initiator

The diazo compound, 2,2'-azobis [2-(2-imidazolin-2-yl) propane] dihydrochloride (AIPC), is a water-soluble radical initiator that can be activated at mild temperatures (37 degrees -40 degrees C). Potential biomedical applications of this compound include the fabrication of hydrogels by radical polymerization (e.g., cell encapsulation or drug delivery) and the thermal sensitization of cancerous cells to induce localized cell death. In this study we evaluated whether this compound could induce cell death at 37 degrees C in vitro and in vivo using a tumor animal model. Cytotoxicity was quantitated with a sulfo-rhodamine B colorimetric assay by monitoring growth inhibition of human glioma cells in vitro. AIPC was entrapped in fibrin gel and exposed to cells in culture as a potential way to localize the compound in a controlled release environment. The mechanism of action for cell death was evaluated by quantitating caspase-3 activity in cells. In vivo studies included human glioma tumors that were grown subcutaneously in rats to study the effect of intra-tumor injections of AIPC. AIPC was also injected subcutaneously into normal tissue. Concentrations of 0.2% and 0.02% (w/v in RPMI medium) showed 93% and 84% inhibition of cell growth in vitro, respectively. Cell-growth inhibition using gel-entrapped AIPC was comparable to that obtained with AIPC in solution after 48 hr (86% inhibition at 0.2% w/v). Exposure to AIPC resulted in a significant increase of caspase activity (up to 163 units after 20 min), suggesting induced apoptosis as a possible mechanism of action of the AIPC. Histological pictures showed that, relative to normal tissue, cancerous tissue was more sensitive to the effects of AIPC.
Annual case volume has no impact on patient outcomes in laparoscopic partial colectomy.

Surgeon case volume has been utilized in the credentialing process as a surrogate for surgeon skill. The purpose of this study was to compare objective outcome measures of laparoscopic partial colectomies performed by laparoscopically skilled surgeons with varying annual case census. We performed a retrospective cohort review of all patients (n = 255) undergoing elective laparoscopic partial colectomy. Patients were grouped according to surgeon’s annual case volume as low annual case volume (LV; n = 48) and high annual case volume (HV; n = 207). HV is defined as performing >20 total cases and >25 cases per year. All demographic and clinical variables were evaluated with univariate logistic regression followed by a multivariate logistic regression model for variables approaching significance. Demographic variables were found to be similar between groups. Only median estimated blood loss (100 vs. 150 mL for HV; p = 0.040) was found to be significantly different between groups. However, this was clinically insignificant, as it did not lead to an increased rate of blood transfusions (0.0 vs. 3.9 % for HV surgeons; p = 0.184). All other variables were similar in both univariate and multivariate logistic regression models. Among surgeons with advanced laparoscopic training, the data suggest that LV surgeons are able to achieve similar outcomes as those who perform the operation routinely. Annual case volume should not be given undue emphasis when deciding whether to award privileges for laparoscopic partial colectomy.
A dual-dual CGE model of an archetype African economy: trade reform, migration and poverty

Abstract We build a CGE model of an archetype African economy to simulate the welfare effects of trade liberalization specifically on poverty. The economy is modeled following a dual-dual framework (Thorbecke, 1993, 1994, 1997) that is characteristic of the structure of a developing country in its middle development phase. This provides the basis for analyzing the distribution of modern and informal sector activities in both rural and urban areas. The interdependence of these four broadly defined sectors is modeled not only in terms of production and consumption decisions within them, but also in terms of labor migration among them, adding a richness which is missing in the standard CGE models. Poverty analysis is integrated in the CGE methodology by endogenizing both intra-group income distributions and the nominal poverty line. The application of standard poverty measures to the pre- and post-simulation poverty lines and distributions of income for each socio-economic group, allows the assessment of policy-induced changes on group specific poverty and national poverty. Simulations with a model calibrated from a social accounting matrix (SAM) of a prototype African economy, show that an important contribution of the dual-dual model vis-a-vis poverty analysis in a CGE model is the inter-group migration it incorporates. Changes in the population shares of the socio-economic groups that follow population shifts have important implications for the magnitudes of changes in national poverty.
Thermal transport through a fluid-solid interface

Abstract Using molecular dynamics we consider the thermal resistances between two fluid (water) reservoirs at uniform hot and cold temperatures separated by solid (silicon) nanowalls. While the influence of the thermal Kapitza resistance on the fluid side of an interface is well known, similar effects on the solid side have not been widely studied. Our results show that these interfacial resistances diminish the wall heat flux by an order of magnitude in comparison with a hypothetical system for which the overall fluid–solid contact resistances are negligible.
Effects of elevated CO2 on foliar quality and herbivore damage in a scrub oak ecosystem

Atmospheric CO2 concentrations have increased exponentially over the last century and continuing increases are expected to have significant effects on ecosystems. We investigated the interactions among atmospheric CO2, foliar quality, and herbivory within a scrub oak community at the Kennedy Space Center, Florida. Sixteen plots of open-top chambers were followed; eight of which were exposed to ambient levels of CO2 (350 ppm), and eight of which were exposed to elevated levels of CO2 (700 ppm). We focused on three oak species, Quercus geminata, Quercus myrtifolia, Quercus chapmanii, and one nitrogen fixing legume, Galactia elliottii. There were declines in overall nitrogen and increases in C:N ratios under elevated CO2. Total carbon, phenolics (condensed tannins, hydrolyzable tannins, total phenolics) and fiber (cellulose, hemicellulose, lignin) did not change under elevated CO2 across plant species. Plant species differed in their relative foliar chemistries over time, however, the only consistent differences were higher nitrogen concentrations and lower C:N ratios in the nitrogen fixer when compared to the oak species. Under elevated CO2, damage by herbivores decreased for four of the six insect groups investigated. The overall declines in both foliar quality and herbivory under elevated CO2 treatments suggest that damage to plants may decline as atmospheric CO2 levels continue to rise.
Development of a Sequential Kinking Terminal for W-Beam Guardrails

A new tangent energy-absorbing W-beam guardrail terminal that meets NCHRP Report 350 criteria has been developed. The terminal, designated the SKT-350, dissipates the energy of an encroaching vehicle by producing a series of plastic hinges in the W-beam as the terminal head is pushed down the guardrail. This energy-absorption concept allows for significantly lower dynamic forces on the encroaching vehicle, reducing the vehicle damage, the weight of the terminal head, the propensity for vehicle yaw and roll after impact, and the chances of buckling in the W-beam section. The energy required to move the head down the rail in this design is optimized for current criteria, but by modifying the bending geometry in the head, the average force to displace the head down the rail can be adjusted from values ranging from 11 to 60 kN (2,500 to 13,500 lb), meaning that the system can be easily modified to meet any future changes in safety performance standards. In addition to these important safety advantages, the te...
Synthesis of 2-deoxy-2[82Br]bromo-d-mannose and related compounds and their biodistributions in mice

The synthesis of 2-deoxy-2-[82Br]bromo-3,4,6-tri-O-acetyl-α-d-mannopyranosyl chloride (compound 3b) and 2-deoxy-2-[82Br]bromo-d-mannose (compound 4d), and their biodistributions in mice are described. The reaction of 3,4,6-tri-O-acetyl-d-glucal (compound 2) with unlabeled and labeled bromine chloride (compounds 1a and 1b) generated in situ from the oxidation of bromide with N-chlorosuccinimide gave unlabeled and labeled 2-deoxy-2-bromo-3,4,6-tri-O-acetyl-α-d-mannopyranosyl chloride (compounds 3a and 3b) with a radiochemical yield of 58% (chemical yield, 63%). The hydrolysis of compounds 3a and 3b with 2N HCl gave 2-deoxy-2-bromo-d-mannose (compounds 4a and 4b) with a radiochemical yield of 72%. The biodistribution of compounds 3b and 4b after injection in mice indicated that 2% of the total injected radioactivity rapidly accumulated in the brain, while 6% of the total injected radioactivity accumulated in the heart; however, the radioactivity started to decline in these two organs after 15 min.
Comprehensive isomorphic subtree enumeration

A fundamental problem in program analysis and optimization concerns the discovery of structural similarities between different sections of a given program and/or across different programs. Specifically, there is a need to find topologically identical segments within compiler intermediate representations (IRs).Such topological isomorphism has many applications. For example, finding isomorphic sub-trees within different expression trees points to common computational resources that can be shared when targeting application-specific hardware. Isomorphism in the controlflow graph can be used to discovery of custom instructions for customizable processors. Discovering isomorphism in context call trees during program execution is invaluable to several JIT compiler optimizations. Thus, all these different applications rely on the fundamental ability to find topologically identical segments within a given tree or graph representation.In this paper, we present a generic formulation of the subtree isomorphism problem that is more powerful than previous proposals. We prove that an optimal quadratic time solution exists for this problem. We employ a dynamic programming based algorithm to efficiently enumerate all isomorphic sub-trees within given reference trees and also demonstrate its efficacy in a production compiler.
To Inhabit Well: Counterhegemonic Movements and the Right to the City

A right to the city, understood as a conjoint claim to a right to inhabit urban space well, can be an effective starting point from which diverse urban movements can begin to build broad counterhegemonic coalitions for alternative urban futures. In this article, I argue that the right to the city supports the project of establishing relations of equivalence among members of coalitions––balancing relations of sameness/difference and interdependence/autonomy.