cssi/SciSciGPT-SciSciNet huggingface dataset:
Investigations on dynamic intensity modulated photon fields in radiation therapy

This thesis investigates the validity of inverse algorithms and delivery techniques in dynamic intensity modulated radiation therapy(IMRT) with the view toward clinical implementation. A dosimetric verification technique used to monitor the dynamic beam delivery was introduced with design considerations and clinical evaluation of various quality assurance (QA) phantoms, facilitating the measurement of dynamic IMRTdose distributions and conversion of photon fluence to machine deliverable monitor units. Benchmark tests using thermoluminescent dosimeters(TLDs), solid state detectors, and films were carried out in realistic clinical examples. This was to demonstrate the precision and degree of accuracy of the proposed techniques both in vitro and in vivo systems using canine subjects with paraspinal tumors. The results of the irradiation of canine subjects indicated that the goal of using IMRT to irradiate target volumes with sparing critical structures was met. However, the measure of physiological response found, was incapable of providing a more accurate measure of the dosedelivered. Quantitative analysis on the influence of systematic and random field perturbations in highly conformal fields with emphasis on the dosimetric outcome is also presented in this thesis. Two sources of uncertainties deemed important in dynamic therapy of photon beams were studied. These were caused by inaccuracies in velocity and in position of both multileaf collimator(MLC) and backup diaphragms. This was attributed to some degree to the tolerance levels or mechanical constraints of beam defining parameters. These errors were simulated using a Gaussian function with standard deviation of ±1.0 mm to assess changes in dose distribution. Based on the results of this study, QA procedures which are unique to the delivery of dynamic beams were proposed.
On the university phase spaces for homogeneous principal bundles

It is shown that the universal phase space for certain homogeneous principal bundles can be interpreted as a co-adjoint orbit in a semi-direct product.
The Molecules of Oral Contraceptives

Molecular models of molecules of oral contraceptives are discussed. The molecules added to the JCE Featured Molecules library this month include: desogestrel, dienogest, drospirenone, estradiol, estradiol valerate, estriol, estrone, ethinyl estradiol, etonogestrel, levonorgestrel, mestranol, norelgestromin, norethisterone, norethisterone acetate, norethynodrel, norgestimate, and progesterone.
Preparation and electrochemical evaluation of poly (3-phenylthiophene) derivatives: Potential materials for electrochemical capacitors

The preparation and electrochemical characterization using cyclic voltammetry, in situ quartz crystal microbalance measurements and ac impedance spectroscopy of five new monomers and polymers for electrochemical capacitors (ECC) are described. High polymerization efficiencies (∼70%) and charge densities (∼190 C g−1) were obtained for poly 3-(3,4-difluorophenylthiophene), MPFPT, and poly 3-(4-fluorophenylthiophene), PFPT. Excellent cycling stability (<1% degradation over 100 cycles) was achieved for MPFPT in both p- and n-doping regimes. This enhanced cyclability is associated with polymers having rigid open structures.
SU-E-T-341: Experimental Evaluation of Free Radical Generation in Nanoparticle-Aided Radiation Therapy

Purpose: Use of gold nanoparticles (NPs) in radiation therapy has been found promising due to the possibility of selective radiation dose enhancement within a tumor, and favorable biological compatibility. Recent studies demonstrated that the biological effect exceeds the expectations based on the physical energy deposition solely, thus pointing toward biochemical factors. Since free radicals are responsible for the majority of the biological damage, evaluation of their radiation induced free radicals near the gold‐tissue interface offers a more relevant estimate of the biological damage in NP‐aided radiation treatments. Methods: Samples in the capillaries were irradiated with clinical Ir‐192 HDR source. Since free radicals are very short‐lived (∼nanoseconds), we used a spin trap agent, high purity DMPO dissolved in water, to trap hydroxyl radicals generated by radiolysis of water. The formed spin adducts retain spin properties of free radicals for a prolonged time (∼hours), especially at low temperatures. Radicals were detected via electron spin resonance (ESR) spectrometry technique. Quantification of free radicals generated in water and in the presence of a thin gold wire was done by double integration of the obtained spectra. Results: Our Monte Carlo simulations demonstrated that the dose enhancement region is limited to a close vicinity (less than 1mm) of the gold‐tissue interface still suitable for free radical measurement with ESR spectroscopy. We have established a protocol for quantitative ESR measurements. The radical generation was found to be proportional to the radiation dose, and strongly enhanced by the presence of gold. Conclusions: Free radicals generated by radiolysis of water can be measured quantitatively with ESR technique. Our evaluation of radiation induced free radical generation in water with nanoparticles sheds some light on the effects of NPs in biological systems. This project is supported through an NRC grant for faculty development. It is grant number NRC‐HQ‐12‐G‐38‐0042.
The ionic liquid isopropylammonium formate as a mobile phase modifier to improve protein stability during reversed phase liquid chromatography.

Abstract The room temperature ionic liquid isopropylammonium formate (IPAF) is studied as a reversed phase HPLC mobile phase modifier for separation of native proteins using a polymeric column and the protein stability is compared to that using acetonitrile (MeCN) as the standard organic mobile phase modifier. A variety of important proteins with different numbers of subunits are investigated, including non-subunit proteins: albumin, and amyloglucosidase (AMY); a two subunit protein: thyroglobulin (THY); and four subunit proteins: glutamate dehydrogenase (GDH) and lactate dehydrogenase (LDH). A significant enhancement in protein stability is observed in the chromatograms upon using IPAF as a mobile phase modifier. The first sharper peak at about 2 min represented protein in primarily the native form and a second broader peak more retained at about 5–6 min represented substantially denatured or possibly aggregated protein. The investigated proteins (except LDH) could maintain the native form within up to 50% IPAF, while a mobile phase, with as low as 10% MeCN, induced protein denaturation. The assay for pyruvate using LDH has further shown that enzymatic activity can be maintained up to 30% IPAF in water in contrast to no activity using 30% MeCN.
The Relationship of Cognitive Abilities Scores with Social Studies Achievement

For a sample of 219 elementary school pupils in the fifth grade, intercorrelations were investigated among four subtest measures: (a) Metropolitan Achievement Test (MAT)—Social Studies, (b) Cognitive Abilities Test (CAT)—Verbal, (c) CAT—Quantitative, and (d) CAT—Non—Verbal. The CAT Verbal score yielded the highest correlation of .73 with the MAT measure.
New developments in image-based characterization of coated particle nuclear fuel

We describe in this paper new developments in the characterization of coated particle nuclear fuel using optical microscopy and digital imaging. As in our previous work, we acquire optical imagery of the fuel pellets in two distinct manners that we refer to as shadow imaging and cross-sectional imaging. In shadow imaging, particles are collected in a single layer on an optically transparent dish and imaged using collimated back-lighting to measure outer surface characteristics only. In cross-sectional imaging, particles are mounted in acrylic epoxy and polished to near-center to reveal the inner coating layers for measurement. For shadow imaging, we describe a curvaturebased metric that is computed from the particle boundary points in the FFT domain using a low-frequency parametric representation. We also describe how missing boundary points are approximated using band-limited interpolation so that the FFT can be applied. For cross-section imaging, we describe a new Bayesian-motivated segmentation scheme as well as a new technique to correct layer measurements for the fact that we cannot observe the true mid-plane of the approximately spherical particles.
A Four-Year Study of the Utilization of Dental Assistants with Expanded Functions

A four-year project was carried out to determine the feasibility of dental practice utilizing auxiliaries with expanded functions in relation to quality, amounts and types of service, and economic considerations. The findings indicated that employment of expanded functions auxiliaries is practical from all three points of view. The individual dentist must decide the number of auxiliary personnel he will employ, depending on potential patient load, his speed, and the types of services he provides.
Methodological issues when comparing hearing thresholds of a group with population standards: the case of the ferry engineers.

OBJECTIVES: To discuss appropriate and inappropriate methods for comparing distributions of hearing thresholds of a study group with distributions in population standards and to determine whether the thresholds of Washington State Ferries engineers are different from those of men in the general population, using both frequency-by-frequency comparisons and analysis of audiometric shape. DESIGN: The most recent hearing conservation program audiograms of 321 noise-exposed engineers, ages 35 to 64, were compared with the predictions of Annexes A, B, and C from ANSI S3.44. There was no screening by history or otoscopy; all audiograms were included. 95% confidence intervals (95% CIs) were calculated for the engineers' median thresholds for each ear, for the better ear (defined two ways), and for the binaural average. For Annex B, where 95% CIs are also available, it was possible to calculate z scores for the differences between Annex B and the engineers' better ears. Bulge depth, an audiometric shape statistic, measured curvature between 1 and 6 kHz. RESULTS: Engineers' better-ear median thresholds were worse than those in Annex A but (except at 1 kHz) were as good as or better than those in Annexes B and C, which are more appropriate for comparison to an unscreened noise-exposed group like the engineers. Average bulge depth for the engineers was similar to that of the Annex B standard (no added occupational noise) and was much less than that of audiograms created by using the standard with added occupational noise between 90 and 100 dBA. CONCLUSIONS: Audiograms from groups that have been selected for a particular exposure, but, without regard to severity, can appropriately be compared with population standards, if certain pitfalls are avoided. For unscreened study groups with large age-sex subgroups, a simple method to assess statistical significance, taking into consideration uncertainties in both the study group and the comparison standard, is the calculation of z scores for the proportion of better-ear thresholds above the Annex B median. A less powerful method combines small age-sex subgroups after age correction. Small threshold differences, even if statistically significant, may not be due to genuine differences in hearing sensitivity between study group and standard. Audiometric shape analysis offers an independent dimension of comparison between the study group and audiograms predicted from the ANSI S3.44 standard, with and without occupational noise exposure. Important pitfalls in comparison to population standards include nonrandom selection of study groups, inappropriate choice of population standard, use of the right and left ear thresholds instead of the better-ear threshold for comparison to Annex B, and comparing means with medians. The thresholds of the engineers in this study were similar to published standards for an unscreened population. Language: en
Highly efficient Raman amplification in a polarization‐preserving optical fiber

In a forward pump configuration, a Raman gain coefficient of 4.8×10−11 cm/W and a gain as high as 40 dB/W have been successfully attained with a combination of 1.34‐μm pump and 1.42‐μm signal pulses. A 20‐dB gain at a wavelength of 1.52 μm was also obtained at a 3.7‐W input. The test fiber is a 1‐km‐long polarization‐preserving and absorption‐reducing type polarization‐preserving fiber which has a GeO2 highly doped core with a small core diameter of 4.5 μm. It is also shown that the 3‐dB gain bandwidth is around 130–135 cm−1 and that optical power ratio of the amplified signal to the spontaneous emission is about 24 dB for the 1.42‐μm 1st Stokes line.
Intact protein analysis for site-directed mutagenesis overexpression products: plasmid-encoded R67 dihydrofolate reductase.

Mass spectrometry is currently the method of choice for the analysis of recombinant protein expression products. By combining proteolytic digestion with peptide mapping and tandem mass spectrometry techniques, verification of site-directed mutagenesis products can be obtained. The proteolytic digestion step converts a purified recombinant protein into a mixture that must be reseparated, thus greatly increasing the analysis time associated with the confirmation of site-directed mutagenesis products. Ion/ion reaction chemistry combined with quadrupole ion trap mass spectrometry provides a fast and efficient way to analyze intact proteins for the correct site-directed mutagenesis products, without heavy reliance on the proteolytic digestion step. Analysis of a series of protein variants (I68M, I68Q, Y69F, and Q67Y) from plasmid-encoded R67 dihydrofolate reductase using ion/ion reaction chemistry confirmed the presence of the correct site-directed mutagenesis products. For the I68M mutant, ion/ion separations detected the presence of extensive degradation from the N-terminal end of the protein. In the case of the Q67Y mutant, a mixture of Q67Y and Q67C species was detected by employing tandem mass spectrometry combined with ion/ion reactions. The ion/ion reaction technique was also performed on a partially purified lysate of the Q67Y/C mixture and successfully screened for the presence of both components in a complex mixture. The ion/ion reaction approach achieved the same results as the proteolytic-digestion-based methodology in a much shorter analysis time.
Comparison of electromigration behaviors of SnAg and SnCu solders

Two commonly used Pb-free solders, SnAg and SnCu, are studied for electromigration (EM) reliability. Two major EM failure mechanisms are identified in Sn-based Pb-free solders, which is mainly due to the differences in microstructures and Sn-grain orientation. In general, the EM damage in SnCu solder is driven by the fast interstitial diffusion of Ni and Cu away from solder/UBM interface and leads to early fails; while the damage in SnAg solders is mostly dominated by Sn-self diffusion resulting in longer lifetime. The effective activation energy is 0.95 eV for SnAg solder and 0.54 eV for SnCu solder. The current density power law exponent is 2 for SnAg and 1.2 for SnCu, respectively. Blech effect is observed in the solders with Sn-self diffusion dominated failures. The roles of Ag and Cu on EM performance will be discussed.
President's message: Dues increase will help build the foundation for AGU's future success

The world is a very different place than it was 43 years ago. In 1969, Jimi Hendrix rocked the legendary Woodstock music festival, Neil Armstrong took the first steps on the Moon, and U.S. drivers paid an average of 35 cents a gallon for gas. Today, digital music files have replaced vinyl records, NASA's Curiosity rover is transmitting data and imagery from the surface of Mars, and a growing number of cars run on alternative fuels. In the same way, 43 years ago AGU was a very different organization. Membership hovered around 10,000, and the Fall Meeting was still in its infancy. Today, AGU's membership has increased to more than 61,000, Fall Meeting attendance has topped 20,000, and an entire generation of geoscientists who weren't even born in 1969 now comprises 28% of our current membership.
Evidence for Diffuse Central Retinal Edema In Vivo in Diabetic Male Sprague Dawley Rats

Background Investigations into the mechanism of diffuse retinal edema in diabetic subjects have been limited by a lack of animal models and techniques that co-localized retinal thickness and hydration in vivo. In this study we test the hypothesis that a previously reported supernormal central retinal thickness on MRI measured in experimental diabetic retinopathy in vivo represents a persistent and diffuse edema. Methodology/Principal Findings In diabetic and age-matched control rats, and in rats experiencing dilutional hyponatremia (as a positive edema control), whole central retinal thickness, intraretinal water content and apparent diffusion coefficients (ADC, ‘water mobility’) were measured in vivo using quantitative MRI methods. Glycated hemoglobin and retinal thickness ex vivo (histology) were also measured in control and diabetic groups. In the dilutional hyponatremia model, central retinal thickness and water content were supernormal by quantitative MRI, and intraretinal water mobility profiles changed in a manner consistent with intracellular edema. Groups of diabetic (2, 3, 4, 6, and 9 mo of diabetes), and age-matched controls were then investigated with MRI and all diabetic rats showed supernormal whole central retinal thickness. In a separate study in 4 mo diabetic rats (and controls), MRI retinal thickness and water content metrics were significantly greater than normal, and ADC was subnormal in the outer retina; the increase in retinal thickness was not detected histologically on sections of fixed and dehydrated retinas from these rats. Conclusions/Significance Diabetic male Sprague Dawley rats demonstrate a persistent and diffuse retinal edema in vivo, providing, for the first time, an important model for investigating its pathogenesis and treatment. These studies also validate MRI as a powerful approach for investigating mechanisms of diabetic retinal edema in future experimental and clinical investigations.
Swept-Leading-Edge Pylon Effects on a Scramjet Pylon-Cavity Flameholder Flowfield

This study explores the effect of adding a pylon to the leading edge of a cavity flameholder in a scramjet combustor. Data were obtained through a combination of wind-tunnel experimentation and steady-state computational fluid dynamics. Wind-tunnel data were collected using surface pressure taps, static and total probe data, shadowgraph flow visualization, and particle image velocimetry. Computational fluid dynamics models were solved using the commercial FLUENT software. The addition of an intrusive device to the otherwise low-drag cavity flamebolder offers a potential means of improving combustor performance by enabling combustion products to propagate into the main combustor flow via the low-pressure region behind the pylon. This study characterized the flowfield effects of adding the pylon as well as the effect of changing Reynolds numbers over the range of approximately 33 x 10 6 to 55 × 10 6 m ―1 at a Mach number of 2. The addition of the pylon resulted in approximately 3 times the mass flow passing through the cavity compared with the cavity with no pylon installed. Reynolds number effects were weak. The addition of the pylon led to the cavity fluid traveling up to the top of the pylon wake and significantly increasing the exposure and exchange of cavity fluid with the main combustor flow.
Kinetics of metal ion absorption on ion-exchange and chelating fibers

Based on a moving boundary model, a rate equation t = k[X + (1 − X) ln(1 − X)] has been derived for fibrous adsorbents. The kinetics of copper ion absorption on acrylic acid grafted polypropylene PP-g-AA (ion-exchange) fibers fit this rate equation during the initial absorption process. The moving boundary particle diffusion model fits the entire ion absorption process of chelating fibers converted from the PP-g-AA fibers. Copper ion absorption of ion-exchange fibers is influenced by the total numbers of ions in the liquid and solid phases. Additional ion absorption can occur in fibers containing previously adsorbed ions, but the kinetics of this subsequent absorption process does not fit the moving boundary model.
Optical absorption spectra of some potentially interesting gases for Cherenkov counters

Abstract For gas Cherenkov counters employing wavelength shifters coupled to normal-glass phototubes, the vacuum ultraviolet transmission of the filler gas is of great interest. We have measured transmission to 1100 A for an optical path of one atmosphere-meter of methane, ethane, Freon 14, propane, butane, isobutane, nitrogen, sulfur hexafluoride, Freon 22, and methyl chloride. Aging results on wavelength shifters are reported.
A study of the bolton and williams grouping of fatty oils according to the iodine number of their unsaponifiable matter

For distinguishing between pure olive oil and olive oil adulterated with other oils, E. R. Bolton and K. A. Williams (Analyst, 55, 5 (1930)) have suggested the use of the iodine numbers of the unsaponifiable matter. Upon this basis, these authors divided the fats and oils into the following four groups: Group 1--iodine numbers 64 to 70---contains the land animal fats and the coconut group of oils. Group 2--iodine numbers 90 to 96--contains the oils from fish, marine animals, and cacao butter. Group 3--iodine numbers 117 to 124 contains the majority of vegetable fats and oils. (The unsaponifiable matter of crude soy-bean oil gives iodine numbers between 75 and 120, that from the refined oil gives values from 117 to 124.) Group d iodine numbers 197 to 206--contains only olive oil. The iodine numbers were determined by the Rosenmund and Kuhnhenn method (Z. Nahr. Genussm. 46. 154 (1923)) . As this procedure appeared promising for the detection of tea seed oil, as well as for other oils which are at times used to adulterate olive oil, the Olive Oil Committee of the American Oil Chemists' Society undertook a collaborative s tudy of the method in order to ascertain whether the method would definitely detect tea seed oil in an olive oil to which 20 per cent of tea seed oil had been added. As a part of the committee working on this study we obtained the following results:
Bursting of Bubbles at an Air–Water Interface

IN a recent communication1, we presented a series of high-speed photographs of bursting bubbles at an air–water interface. These photographs demonstrate the manner in which small airborne droplets evolve from the vertical water jet which forms upon collapse of the bubble cavity. These studies were carried out as a contribution to the understanding of the role of bursting bubbles in the production of atmospheric sea-salt nuclei2. It was stated that our study was confined to bubbles of 0.2–0.02 cm. diameter. In this region the jet mechanism appears to be the only one responsible for the production of airborne nuclei. We did not imply that the production of airborne salt was entirely via the jet mechanism. For example, in a study of foam patches, it may turn out that the production of droplets is predominantly from the collapse of the bubble film3.
The null hypothesis is not called that for nothing: statistical tests in randomized trials

This article aims to update readers on different ways to arrange one's thinking about conventional null hypotheses in randomized trials. It covers basic criticism of conventional hypotheses and, beyond this, covers relevant developments in methodological, organizational, and science policy arenas. This article includes coverage of new ways to frame null hypotheses, new technical resources, standards for registering trials and reporting on them, cumulating results, common mistakes, and post-trial analysis of null results. The paper includes ideas for research and development on each topic.
Mutations in the Bacillus subtilis β Clamp That Separate Its Roles in DNA Replication from Mismatch Repair

The β clamp is an essential replication sliding clamp required for processive DNA synthesis. The β clamp is also critical for several additional aspects of DNA metabolism, including DNA mismatch repair (MMR). The dnaN5 allele of Bacillus subtilis encodes a mutant form of β clamp containing the G73R substitution. Cells with the dnaN5 allele are temperature sensitive for growth due to a defect in DNA replication at 49°C, and they show an increase in mutation frequency caused by a partial defect in MMR at permissive temperatures. We selected for intragenic suppressors of dnaN5 that rescued viability at 49°C to determine if the DNA replication defect could be separated from the MMR defect. We isolated three intragenic suppressors of dnaN5 that restored growth at the nonpermissive temperature while maintaining an increase in mutation frequency. All three dnaN alleles encoded the G73R substitution along with one of three novel missense mutations. The missense mutations isolated were S22P, S181G, and E346K. Of these, S181G and E346K are located near the hydrophobic cleft of the β clamp, a common site occupied by proteins that bind the β clamp. Using several methods, we show that the increase in mutation frequency resulting from each dnaN allele is linked to a defect in MMR. Moreover, we found that S181G and E346K allowed growth at elevated temperatures and did not have an appreciable effect on mutation frequency when separated from G73R. Thus, we found that specific residue changes in the B. subtilis β clamp separate the role of the β clamp in DNA replication from its role in MMR.
High-Voltage Testing of a High-Capacity, Liquid-Nitrogen Cooled Cable

In recent years, a number of research projects have been initiated to study the application of unconventional technologies to extend the capacity of underground power transmission systems. General Electric Corporate Research and Development has recently completed a three-year study of resistive cryogenic cable systems. This study was sponsored by the Edison Electric Institute, the Tennessee Valley Authority, and the American Public Power Association. The results of this research indicate that the application of cryogenic technology to the development of high-capacity underground transmission systems is within the scope of current technology, and should be economically competitive at single-circuit capacities over 3000 MVA.
Acquiring knowledge by explaining observed problem solving

Learning by Understanding Explanations (LBUE) can be an important tool for automatic knowledge acquisition in diagnostic domains. It takes fuller advantage of an expert's knowledge than some more automatic approaches and uses model-based reasoning to reduce brittleness. LBUE specifically integrates the learning of efficiency information as in Explanation Based Generalization (EBG) with further learning of the causal model. Expert protocols are coded into a machine readable form and then input to the LBUE process. The result of learning is that the system becomes capable of solving the same problem in the future and is also able to apply any newly learned causal model information to novel but similar cases.
The effects of crab bioturbation on Mid-Atlantic saltmarsh tidal creek extension: Geotechnical and geochemical changes

Understanding saltmarsh response to sea-level rise is critical for management and mitigation of these valuable coastal areas. However, comprehensive field studies of sea-level driven changes to the marsh landscape that consider combined biological, geological, and hydrodynamic interactions are rare. This study analyzes ecophysical feedbacks from crab colonization and bioturbation on geotechnical and geochemical properties of the soil in a Mid-AtlanticSpartina alterniflorasaltmarsh. The studyareais within a marsh that is experiencing creek extension due to accelerated sea-level rise and increasing periods of marsh inundation. Measurements of redox potential, pH, belowground biomass, and soil strength reveal that intense crab bioturbation by Sesarma reticulatum significantlychanges the biogeochemical properties ofthesoil.Oxidizedconditionsintheupper10e15cmofthemarshinducedbyburrowingcausesenhanced degradation of S. alterniflora belowground biomass (roots and rhizomes, reduction from 1.9 � 0.6 kg/m 2 to 1.1 � 0.4 kg/m 2 ), which reduces the structural integrity of the soil. This process ultimately increases the
Effects of White-tailed Deer (Odocoileus virginianus Zimm.) Herbivory in Restored Forest and Savanna Plant Communities

Abstract Despite the widespread interest in plant community restoration, few studies have assessed white-tailed deer (Odocoileus virginianus Zimm.) herbivory on herbaceous species and even fewer studies have focused on deer herbivory in restored plant communities. During 2007–2009, we investigated the effect of deer density and associated deer browse on two restored forest and three restored savanna plant communities in Lake County, Illinois. We used 300 small (1.4 m diameter × 1.6 m height) exclosed plots and 1-m2 unexclosed plots to compare the effects of deer herbivory on forbs. We quantified and compared percent non-herbaceous ground cover, species diversity, species evenness, and floristic quality between exclosed plots and unexclosed plots, as well as among preserves within each plant community type. Species diversity and floristic quality of forbs may be maximized at a deer density between 6–22 deer km2 in restored forest communities in northeastern Illinois. Floristic quality was higher in exclose...
Enhancement of UV survival, UV- and MMS-mutability, precise excision of Tn10 and complementation of umuC by plasmids of different incompatibility groups.

Abstract 29 conjugative resistance and colicin plasmids from 19 different incompatibility (Inc) groups were examined for their ability to enhance post-ultraviolet (UV) survival and UV- and methyl methanesulfonate(MMS)-induced mutability in Salmonella typhimurium LT2 strains. 14 Muc+ plasmids enhanced each of the survival and mutation-related properties tested, while 14 Muc− plasmids showed no enhancing effects in any tests. One Muc+ plasmid, pRG1251 (IncH1), enhanced post-UV survival and each of the mutation-related properties tested, except MMS-induced mutagenesis. Two further noteworthy plasmids, R391 (IncJ) and R394 (IncT), produced apparent strain-dependent effects in S. typhimurium which differed from those reported to have been found in Escherichia coli. Plasmid R391 enhanced post-UV survival in S. typhimurium, in contrast to its UV-sensitizing effects in E. coli. In both hosts plasmid R391 enhanced UV- and MMS-induced mutagenesis. Plasmid R394 had no enhancing effects on UV survival or UV- and MMS-induced mutagenesis in S. typhimurium, in contrast to its reported enhancement of MMS-induced mutagenesis in E. coli. Conjugal transfer of R394 to E. coli strain AB1157 and assays of mutagenesis-related traits supported results observed in S. typhimurium. Muc+ plasmids were found to enhance the frequency of precise excision of the transposom Tn10 when inserted within hisG or trpA in S. typhimurium strains. Precise excision could be further enhanced in S. typhimurium by UV-irradiation. Analysis of Tn10 mutants with altered IS10 ends indicated that intact inverted repeats at the ends of Tn10 were required for efficient enhancement of precise excision.
Three-Dimensional Echocardiographic Analysis of Mitral Annular Dynamics Implication for Annuloplasty Selection

Background—Proponents of flexible annuloplasty rings have hypothesized that such devices maintain annular dynamics. This hypothesis is based on the supposition that annular motion is relatively normal in patients undergoing mitral valve repair. We hypothesized that mitral annular dynamics are impaired in ischemic mitral regurgitation and myxomatous mitral regurgitation. Methods and Results—A Philips iE33 echocardiographic module and X7–2t probe were used to acquire full-volume real-time 3-dimensional transesophageal echocardiography loops in 11 normal subjects, 11 patients with ischemic mitral regurgitation and 11 patients with myxomatous mitral regurgitation. Image analysis was performed using Tomtec Image Arena, 4D-MV Assessment, 2.1 (Munich, Germany). A midsystolic frame was selected for the initiation of annular tracking using the semiautomated program. Continuous parameters were normalized in time to provide for uniform systolic and diastolic periods. Both ischemic mitral regurgitation (9.98±155 cm2)...
The money supply process in pre-revolutionary Iran

Abstract Much of the literature on developing countries contends that for all practical purposes the money supply, because of the lack of appropriate tools, is beyond the control of the local monetary authorities. The purpose of this paper is to determine whether and to what extent the Iranian monetary authorities, the Bank Markazi, were able to control that country's money supply, particularly during the oil boom years of the 1970s. Based on an empirically tested model, the paper indicates that the country's monetary authorities were able to make a significant contribution to that country's socio-economic development through monetary control, thus avoiding to a certain extent the tremendous inflationary impact that might have been associated with the 1973–1974 oil boom.
Method and Theory In Comparative Urban Studies

There is a sharp methodological division in comparative urban research between quantitative and qualitative research. This paper explores the relationship between these contrasting research strategies, theoretical assumptions, and empirical results. It begins by defining what is meant by urbanization and reviewing the contending theories of cities and macrostructural change. A section on methods in comparative urban research sketches out the different research generas and provides examples of each. I argue that there has been a paradigm shift in comparative urban research (mirroring wider theoretical currents in macrosociology) toward a framework rooted in international political economy. Qualitative case studies of problems of particular Third World cities and urban systems were instrumental in debunking the developmentalist assumptions of the old "modernization theory"/ecological approach. If qualitative work helps to develop new theoretical insights, the strength of quantitative studies is that they force scholars to explicitly specify fuzzy concepts in a rigorous "operationalizable" manner. Despite its higher prestige in social science in the United States, some statistical analysis is limited by a tendency to simply "test" competing hypotheses, instead of building more fully elaborated nuanced models. Nevertheless, comparative urban research needs to recognize the strengths of both methodological strategies-both are valuable tools to understand cities and urban systems. Real advances in the comparative study of cities will only come if researchers using disparate methods recognize this and work to integrate their findings in an effort to build a synthetic theory of comparative urbanization.
Endothelial cell death on biomaterials: Theoretical and practical aspects of investigation

The use of endothelial cell seeding has been proposed as a solution to increase the patency of blood-contacting devices. While there has been a great deal of research into both biological and mechanical mechanisms of failure, relatively little work involving the effects which biomaterials have on the function of cells seeded on such devices has been conducted. We hypothesize, based on previously published results, that endothelial cells attached to synthetic biomaterials exhibit increased intracellular levels of superoxide and other reactive oxygen species. Previous reports have linked elevated levels of reactive oxygen species to NF-κB activation and subsequent cell death via anoikis, a form of apoptosis. Because of this, it is critical that an understanding of how biomaterials affect cellular behavior is developed, and that this knowledge is used in the creation of future devices which rely on cell seeding and cellular ingrowth.
Crystal structure of a p53 tumor suppressor-DNA complex: Understanding tumorigenic mutations

Mutations in the p53 tumor suppressor are the most frequently observed genetic alterations in human cancer. The majority of the mutations occur in the core domain which contains the sequence-specific DNA binding activity of the p53 protein (residues 102-292), and they result in loss of DNA binding. The crystal structure of a complex containing the core domain of human p53 and a DNA binding site has been determined at 2.2 angstroms resolution and refined to a crystallographic R factor of 20.5 percent. The core domain structure consists of a beta sandwich that serves as a scaffold for two large loops and a loop-sheet-helix motif. The two loops, which are held together in part by a tetrahedrally coordinated zinc atom, and the loop-sheet-helix motif form the DNA binding surface of p53. Residues from the loop-sheet-helix motif interact in the major groove of the DNA, while an arginine from one of the two large loops interacts in the minor groove. The loops and the loop-sheet-helix motif consist of the conserved regions of the core domain and contain the majority of the p53 mutations identified in tumors. The structure supports the hypothesis that DNA binding is critical for the biological activity of p53, and provides a framework for understanding how mutations inactivate it.
Feasibility study: Real-time 3-D ultrasound imaging of the brain

We tested the feasibility of real-time, 3-D ultrasound (US) imaging in the brain. The 3-D scanner uses a matrix phased-array transducer of 512 transmit channels and 256 receive channels operating at 2.5 MHz with a 15-mm diameter footprint. The real-time system scans a 65° pyramid, producing up to 30 volumetric scans per second, and features up to five image planes as well as 3-D rendering, 3-D pulsed-wave and color Doppler. In a human subject, the real-time 3-D scans produced simultaneous transcranial horizontal (axial), coronal and saggital image planes and real-time volume-rendered images of the gross anatomy of the brain. In a transcranial sheep model, we obtained real-time 3-D color flow Doppler scans and perfusion images using bolus injection of contrast agents into the internal carotid artery. (E-mail: stephen.w.smith@duke.edu) © 2004 World Federa- tion for Ultrasound in Medicine & Biology.
The autonomous underwater glider "Spray"

A small (50-kg, 2-m long) underwater vehicle with operating speeds of 20-30 cm/s and ranges up to 6000 km has been developed and field tested. The vehicle is essentially an autonomous profiling float that uses a buoyancy engine to cycle vertically and wings to glide horizontally while moving up and down. Operational control and data relay is provided by GPS navigation and two-way communication through ORBCOMM low-Earth-orbit satellites. Missions are envisioned with profile measurements repeated at a station or spaced along a transect. The initial instrument complement of temperature, conductivity, and pressure sensors was used to observe internal waves and tides in the Monterey underwater canyon.
Antioxidant Properties of Rosemary Oleoresin in Turkey Sausage

Rosemary oleoresin (20 ppm) was used as an antioxidant in turkey breakfast sausages prepared with 75% hand deboned turkey meat and 25% mechanically deboned turkey meat. It was compared to similarly formulated products with butylated hydroxyanisole/butylated hydroxytoluene (BHA/BHT, 200 ppm) and a control with no antioxidants. 2-Thiobarbituric acid-reactive substances in samples stored at 4°C demonstrated that rosemary oleoresin was comparable to a commercial blend of BHA/BHT/citric acid in suppressing lipid autoxidation. Sensory analysis was in agreement with these results. Analysis of volatile aroma compounds revealed the occurrence of oxidatively derived carbonyls in the sausages without antioxidants, while the antioxidant-treated sausages were essentially free from these carbonyls.
Measured performance of a wireless LAN

The performance of a high-speed commercial spread-spectrum wireless LAN that uses the CSMA/CA multiple-access strategy was studied. Using synthetic workloads, packet capture success rather than signal propagation characteristics was measured. Specifically throughput, packet loss rates, range, and patterns of errors within packets were measured. It is concluded that CSMA/CA is quite successful in allocating bandwidth under stress, but that packet capture rate degrades very quickly once the LAN's effective range is exceeded. Hence, network maintainers should plan the layout of wireless networks at least as carefully as they plan wired networks. >
Reichenbach, Reference Classes, and Single Case ‘Probabilities’

Perhaps the most difficult problem confronted by Reichenbach’s explication of physical probabilities as limiting frequencies is that of providing decision procedures for assigning singular occurrences to appropriate reference class, i.e., the problem of the single case.1 Presuming the symmetry of explanations and predictions is not taken for granted, this difficulty would appear to have two (possibly non-distinct) dimensions, namely: the problem of selecting appropriate reference classes for predicting singular occurrences, i.e., the problem of (single case) prediction, and the problem of selecting appropriate reference classes for explaining singular occurrences, i.e., the problem of (single case) explanation. If the symmetry thesis is theoretically sound, then these aspects of the problem of the single case are actually non-distinct, since any singular occurrence should be assigned to one and the same reference class for purposes of either kind; but if it is not the case that singular occurrences should be assigned to one and the same reference class for purposes of either kind, then these aspects are distinct and the symmetry thesis is not sound.2
Noradrenergic and Endogenous Opioid Pathways in the Regulation of Luteinizing Hormone Secretion in the Male Rat

Endogenous opioid pathways (EOPs) appear to play a role in the tonic regulation of pulsatile LH secretion. The mechanism by which EOPs influence LH release is not known. However, the observation that acute chemical disruption of the noradrenergic (NE) system by a-receptor-blocking agents or NE synthesis inhibitors blocks the LH increase occurring in response to naloxone (NAL) suggests that the ability of EOPs to influence LH secretion may depend upon a functional NE system. We hypothesized that if EOPs required an interacting NE system to influence LH secretion, then rats that have ascending NE tract lesions would not respond to NAL with an increase in LH. To test this hypothesis, we challenged NE-lesioned and sham-lesioned rats with NAL. Young adult male rats received either a NE lesion or a sham lesion and 6 weeks later were implanted with jugular catheters. On the following day, four baseline blood samples (400 μl at 10-min intervals) were taken from NE-lesioned and sham-lesioned rats. All rats were th...
Wearable multisensor heart rate monitor

This presentation provides a description of the challenges of wearable optical and acoustic vital sign sensors integrated in work equipment. It proposes a solution to the artifact and wearability problems by (1) using a combination of sensing techniques (2) placing the sensors at various key locations on the body and (3) applying data fusion algorithms that adapt to varying levels of noise.
Biologic constraints on modelling virus assembly

The mathematic modelling of icosahedral virus assembly has drawn increasing interest because of the symmetric geometry of the outer shell structures. Many models involve equilibrium expressions of subunit binding, with reversible subunit additions forming various intermediate structures. The underlying assumption is that a final lowest energy state drives the equilibrium toward assembly. In their simplest forms, these models have explained why high subunit protein concentrations and strong subunit association constants can result in kinetic traps forming off pathway partial and aberrant structures. However, the cell biology of virus assembly is exceedingly complex. The biochemistry and biology of polyoma and papillomavirus assembly described here illustrates many of these specific issues. Variables include the use of cellular ‘chaperone’ proteins as mediators of assembly fidelity, the coupling of assembly to encapsidation of a specific nucleic acid genome, the use of cellular structures as ‘workbenches’ upon which assembly occurs, and the underlying problem of making a capsid structure that is metastable and capable of rapid disassembly upon infection. Although formidable to model, incorporating these considerations could advance the relevance of mathematical models of virus assembly to the real world.
Kinetic mass spectrometric determination of the absolute rate coefficient for the reaction NH3+ (ν = 0) + NH3 → NH4+ + NH2 at thermal kinetic energies

Abstract The absolute thermal rate coefficient for the reaction NH3+ + NH3 → NH4+ + NH2 has been determined experimentally for the first time for NH3+ (ν = 0) reactant ions. An increase in Evib results in a decrease in the rate coefficient for proton transfer.
Factors affecting medical student career choice of psychiatry from 1999 to 2001.

Objective: The proportion of students matching into psychiatry (PMP) at each medical school results from a complex interplay between extrinsic (e.g., national trends, geographic region) and intrinsic factors (e.g., the quality of psychiatric education). The goal of the study was to learn the extent to which regional and local extrinsic factors (and one intrinsic factor) influenced PMP at medical schools in the U.S. from 1999 to 2001. Methods: The authors obtained data about these factors from deans of student affairs, the National Resident Matching Program (NRMP), American Medical Association (AMA), Association of American Medical Colleges (AAMC), American Psychiatric Association (APA), and Harvard University’s HealthSystem Consortium. Results: The best predictor of a school’s PMP is the PMP of the prior year for that particular school. Local and regional extrinsic factors were not significantly associated with PMP. There was a modest inverse correlation between PMP and the proportion of international medical graduates (IMGs) in psychiatry residency. Conclusions: The authors infer that intrinsic factors are most important for recruitment, and they make recommendations for addressing these factors.
Familial clustering of endometrial cancer in a well-defined population

Abstract Objective Using a genealogical database, we examined risk of endometrial cancer among family members of individuals with endometrial cancer. Methods We identified endometrial cancer cases in the Utah Population Database (UPDB), a computerized archive of genealogy data linked to the Utah Cancer Registry. We tested for excess relatedness and estimated relative risks (RR) among first-, second-, and third-degree relatives of endometrial cancer cases and stratified analyses by tumor histology and body mass index (BMI). Results We identified 3911 cases; 3546 were Type I cancers and 365 Type II cancers. The RR for all endometrial cancer cases and for cases with type I histology was significantly increased for first-, second-, and third-degree relatives. An almost three-fold risk was observed among first-degree relatives of individuals with Type I cancers and a 2.24-fold risk among second-degree relatives of Type I morbidly obese cases. The magnitude of endometrial cancer risk among relatives appeared to increase with case BMI. Conclusions The elevated risks for endometrial cancer among first-, second-, and third-degree relatives support a genetic contribution to predisposition to endometrial cancer. The increased risk appears to be limited to Type I endometrial cancer. We observed increased risks for endometrial cancer among relatives of obese and morbidly obese Type I cases, which may be indicative of a synergistic relationship between underlying genetic propensity and shared environment. This study quantifies risk of developing cancer among relatives of patients with disease and provides the basis for further analysis of high risk pedigrees and gene identification for genetic etiologies of endometrial cancer.