cssi/SciSciGPT-SciSciNet huggingface dataset:
VARIATION OF FREE RADICAL CONCENTRATION WITH MOLECULAR WEIGHT IN PETROLEUM FEEDSTOCKS

Two petroleum residua were studied, one of Mid-Eastern original and the other of Chinese origin. These residua were separated into fractions using preparative size-exclusion chromatography (SEC). Room temperature electron spin resonance (ESR) experiments of SEC separated petroleum-derived fractions are described. A variation of free radical concentration with different molecular weight fractions was observed. Significant increase in free radical concentration was observed in the 1000-2500 amu range. This is in the molecular weight range postulated to be necessary for formation of the mesophase state observed in carbonaceous pitches during conversion to coke and carbon by thermal treatment.
Donor-acceptor-pair photoluminescence in Ga-doped ZnO thin films grown by plasma-assisted molecular beam epitaxy

Three dominant emission lines: neutral GaZn donor bound exciton I8 (3.359 eV); ionized GaZn donor bound exciton I1 (3.368–3.371 eV), and donor-acceptor-pair (DAP) IDA (3.313–3.321 eV) were observed in the 9 K photoluminescence (PL) spectra from a series of Ga-doped ZnO thin films with electron carrier concentration (n) ranging from 3.6×1018 to 3.5×1019 cm−3. As n increases, the dominant PL line changes from I1 to IDA, and finally to I8. Characteristic blueshifts of IDA PL lines were observed with increasing n, with increasing excitation power in power-dependent PL spectra, and with increasing temperature in temperature-dependent PL spectra. The experimental results of IDA lines in Ga-doped ZnO are generalized to a proposed model to explain the possibilities of the widely observed 3.30–3.32 eV PL lines in ZnO as DAP transitions, which are associated with a shallow donor (e.g., Ga, Al, In, H, etc) with an ionization energy of ∼44–65 meV and a deep acceptor VZn with an ionization energy of ∼180 meV.
Human drug abuse liability assessment: opioids and analgesics

Methods are described for assesment of the abuse liability of opioids and analgesics. The methods developed by the USPHS Addiction Research Center for assessment of opioid abuse liability have served as the prototype for most currently used abuse liability assessment approaches. The general method is that of comparing the profile of effects of a test drug to the profiles of placebo and of a known drug of abuse. Drugs with profiles of activity similar to the known drug of abuse are considered pharmacologically equivalent and of similar abuse liability
The Newton-Raphson approximation applied to the Navier-Stokes equations with application to the base flow problem

When the Newton-Raphson method is applied to the Navier–Stokes equations for axisymmetric flow, both Stokes and Oseen approximations may be obtained depending on the trial solutions selected. This suggests that the method may be continued to obtain higher order, and presumably better approximate solutions to the Navier-Stokes equations. The method is illustrated on the axisymmetric base flow problem. Wendet man das Newtonsche Verfahren auf die Navier-Stokesschen Differentialgleichungen fur die axialsymmetrische Stromung an, so kann man im ersten Schritt bei geeigneter Wahl der Anfangsnaherungen sowohl die Stokessche wie auch die Oseensche Naherung erhalten. Diese Beobachtung legt es nahe, das Verfahren fortzusetzen, um auf diesem Wege Naherungen hoherer Ordnung zu erhalten, die dann auch mutmaslich besser sind. Das Verfahren wird an einem Beispiel vorgefuhrt.
An Autonomous Distributed Control Method for Link Failure Based on Tie-Set Graph Theory

This study proposes an autonomous distributed control method for single link failure based on loops in a network. This method focuses on the concept of tie-sets defined by graph theory in order to divide a network into a string of logical loops. A tie-set denotes a set of links that constitutes a loop. Based on theoretical rationale of graph theory, a string of tie-sets that cover all the nodes and links can be created by using a tree, even in an intricately-intertwined mesh network. If tie-sets are used as local management units, high-speed and stable fail-over can be realized by taking full advantage of ring-based restoration. This paper first introduces the notion of tie-sets, and then describes the distributed algorithms for link failure. Experiments are conducted against Rapid Spanning Tree Protocol (RSTP), which is generally used for fault recovery in mesh topological networks. Experimental results comparing the proposed method with RSTP suggest that our method alleviates the adverse effects of link failure with a modest increase in state information of a node.
Fire in the City: Savonarola and the Struggle for Renaissance Florence

ACKNOWLEDGMENT LIST OF ILLUSTRATIONS AN X-RAY OF FLORENTINE GOVERNMENT GLOSSARY OF TERMS Ch. 1 - Chorus Ch. 2 - Vile Bodies: 1472-1490 Ch. 3 - The Friar Returns: 1490-1491 Ch. 4 - The Wait: 1492-1494 Ch. 5 - Fear and Loathing: November 1494 Ch. 6 - Holt Liberty Ch. 7 - Stamping out Tyranny: 1494-1495 Ch. 8 - God and Politics Ch. 9 - Angels and Enforcers: 1496-1498 Ch. 10 - The Pope and the Friar: 1495-1497 Ch. 11 - The Savonrolan Moment Ch. 12 - Wailers and Bigots Ch. 13 - Excommunication: May-June 1497 Ch. 14 - Five Executions: August 1497 Ch. 15 - Rome Closes In Ch. 16 - Foiled Fire Ch. 17 - The Siege of San Marco: April 1498 Ch. 18 - Confessions of a Sinner Ch. 19 - Fire Again: Three Executions: May 1498 Ch. 20 - The Conscience of a City NOTES BIBLIOGRAPHY INDEX
‘Refusing to believe it’: Responses, reflections, and (partial) recantations

Reponse aux commentaires apportes par The normal research collective et par F. Joseph a l'article de l'A. consacre a la critique de la conception civique et humaniste de la pedagogie du discours public (in «Social epistemology», 11, 3-4, 1997, pp. 253-348). Rejetant les diverses accusations de cynisme, de conservatisme, ainsi que toute filiation a Tocqueville ou N. Postman, l'A. poursuit sa reflexion sur les particularites de la pedagogie et de la pratique du discours public en reprenant les problematiques de la subjectivite comme performance, de l'anti-modernisme et du postmodernisme, de l'assimilationnisme et de la difference culturelle, soulevees par ses lecteurs
Nephron‐sparing surgery for renal cell carcinoma

In summary, NSS is the indicated treatment for patients with localized RCC and an intercurrent urological or medical condition that poses a threat to overall renal function. Recent studies have clarified the role of NSS in patients with localized unilateral RCC and a normal contralateral kidney. Recent results indicate that radical nephrectomy and NSS provide equally effective curative treatment for patients who present with a single, small (< 4 cm), and clearly localized RCC. The long-term renal functional advantage of NSS with a normal opposite kidney requires further study.
Genome wide association identified colorectal cancer susceptibility loci and colorectal cancer risk in Lynch syndrome

Background Recent genome-wide association studies (GWAS) have identified several common low-risk variants for colorectal cancer. Although some of the GWAS were enriched for young onset and family history positive colorectal cancer cases, it is not clear if these variants modify colorectal cancer risk for people with Lynch syndrome. In a case-unaffected sibling analysis of population and clinic based sibships, a study by Poynter et al. (2007) found a stronger association for risk variants in the 8q24 region (rs10505477 and rs6983627) with microsatellite instability (MSI)-high tumors. MSI-high tumors are characteristic of Lynch syndrome. Therefore we hypothesize that these variants may also influence colorectal cancer risk in Lynch syndrome. Recently Wijnen et al. (2009) have reported on some of the GWAS risk variants in Dutch Lynch syndrome families and although they did not find an association between rs6983627 and colorectal cancer risk, other risk variants in 8q24 and 9p24 have yet to be characterized in Lynch syndrome.
Adatoms, strings and epitaxy on singular surfaces

Abstract A computer simulation has been developed to describe epitaxy mediated by random nucleation and anisotropic growth of orthogonal “strings”. The simulation efficiently combines Monte Carlo techniques for randomizing the spatial location of events with a rate equation for determining the time step between events. In all cases, after initiation of epitaxy, the layer distribution of surface atoms evolves towards a pseudo-steady state which is symmetric, Gaussian, and from which surface diffraction intensities oscillate persistently. As the ratio between string nucleation and growth rates increases, this steady-state distribution widens, and the oscillation amplitude decreases. The simulation represents a simplified subset of the growth rules thought to govern molecular beam epitaxy of Si on Si(001).
Selective cues to forget can fail to cause forgetting

Recent research has found that individuals can selectively forget a subset of items through directed forgetting. The goal of the present study was to replicate this selective directed forgetting effect and elucidate its underlying mechanisms. Unfortunately, results from four experiments failed to find any evidence of selective directed forgetting. Participants failed to forget any items when instructed to forget a subset of items from a first list before learning a second list. Participants were only successful in forgetting items from the first list when they were instructed to forget all items from the first list before learning the second list.
Aromaticity and amyloid formation: Effect of π-electron distribution and aryl substituent geometry on the self-assembly of peptides derived from hIAPP22–29

A comprehensive investigation of peptides derived from the 22–29 region of human islet amyloid polypeptide (hIAPP) that contain phenylalanine analogs at position 23 with a variety of electron donating and withdrawing groups, along with heteroaromatic surrogates, has been employed to interrogate how π-electron distribution effects amyloid formation. Kinetic aggregation studies using turbidity measurements indicate that electron rich aromatic ring systems consistently abolish the amyloidogenic propensity of hIAPP22–29. Electron poor systems modulate the rate of aggregation. Raman and Fourier transform infrared spectroscopy confirm the parallel β-sheet secondary structure of aggregates derived from peptides containing electron poor phenylalanine analogs and provide direct evidence of ring stacking. Transmission electron microscopy confirms the presence of amyloid fibrils. The effect of aryl substituent geometry on peptide self-assembly reveals that the electronic nature of substituents and not their steric profile is responsible for failure of the electron donating group peptides to aggregate. Non-aggregating hIAPP22–29 peptides were found to inhibit the self-assembly of full-length hIAPP1–37. The most potent inhibitory peptides contain phenylalanine with the p-amino and p-formamido functionalities. These novel peptides may serve as leads for the development of future aggregation inhibitors. A potential mechanism for inhibition of amylin self-assembly by electron rich hIAPP22–29 peptides is proposed.
Microwave Plasma CVD of Silicon Nanocrystalline and Amorphous Silicon as a Function of Deposition Conditions

Using ECR-CVD (electron cyclotron resonance-chemical vapor deposition), we can make amorphous-silicon (a-Si) and nanocrystalline (nc-Si) thin films. We are looking forward to improve the photo/dark conductivity ratio (σp/σd) by measuring the photo and dark current-voltage (I-V). In the ECR deposition, there are several factors which we can control and adjust for improved results, such as the amounts of silane and argon, the vacuum, and the temperature of the substrate. These become the critical factors for ECR deposition in order to make better films. Input gases consist of Ar, 2%SiH4 in He and H2. In the process, SiH4 is decomposed into SiHx. A residual gas analyzer (RGA) gives composition in the plasma. Because Ar possibly etches the substrate and Si is to be deposited, the best RGA signal is obtained with low Ar content. This work serves to correlate process conditions, RGA signals and electrical data. The best RGA signal occurs for 5 mTorr Ar, 60 mTorr SiH4:He, and power of 600 W. Best value of dark conductivity (σd) was 1.53 × 10-9 S/cm and1.58 × 10-5 S/cm for photo conductivity (σp and low value of σd indicate material with fewer defects. Adding extra H2 improves the photo-conductivity (σp). Applications of these films are heterojunction solar cells and thin film transistors. The heterojunction solar cell had a structure of metal grid/ 500°A of aSi:H/p-Si wafer/Ohmic contact. These cells gave an open circuit voltage (Voc) = 0.51 (V) and short circuit current density (Jsc) = 5.5 mA/cm2 under 50mW/cm2 tungsten halogen lamp. Thin film transistors using nc-Si, with gate length/width (L/W) =450/65 gave field effect mobility of 18 cm2/V-s, and Ion/Ioff of 1.25×105.
Proton (1H) MR spectroscopy of the breast.

Proton (hydrogen 1) [1H]) magnetic resonance (MR) spectroscopy provides biochemical information about the tissue under investigation. Its diagnostic value in cancer is typically based on the detection of elevated levels of choline compounds, choline being a marker of active tumor. The two main potential clinical applications of 1H MR spectroscopy are (a) as an adjunct to breast MR imaging to improve specificity in differentiating benign from malignant lesions, and (b) for monitoring or even predicting response to treatment in patients undergoing neoadjuvant chemotherapy. Preliminary data are promising, with study results suggesting that 1H MR spectroscopy may decrease the number of benign biopsies recommended on the basis of MR imaging findings and may help predict response as early as 24 hours after the first dose of neoadjuvant chemotherapy. Although several limitations currently exist that make the technique premature for clinical use, further evaluation with larger, preferably multicenter trials is ce...
Nutrition Education for Spanish-speaking Young Children and Their Families

Abstract LEARNING OUTCOME: To describe three essential components of effective nutrition education programs and materials targeted at Spanish-speaking young children and their families. Nutrition education resources were developed for use in programs which serve Spanish-speaking families with young children. Resources include nutrition education lessons for young children, songs and coloring sheets for children, and handouts for parents about a variety of health and nutrition topics. They were designed to go beyond a simple translation of English materials into Spanish by including three essential components of effective nutrition education programs for this audience: cultural-sensitivity, appropriate use of language, and involvement of parents and other family members. Program materials encourage families to retain their ethnic heritage as they learn healthful nutrition practices, emphasizing the culture's dietary strengths and offering acceptable alternatives to less-healthy practices. Program materials allow for either Spanish only to be used, or a combination of English and Spanish, to match the audience. Spanish-speaking children are often fairly bilingual, but if Spanish only is spoken at home, they may not yet have learned English words for mealtime conversations, such as the names of foods and other nutrition and health terms. Programs for young children often include English-speaking as well as Spanish-speaking children. Depending on the audience, speaking Spanish or a combination of English and Spanish, not only helps young children learn positive dietary and health practices, but also helps them become more bilingual, and demonstrates respect for both cultures. Providing written materials in Spanish for parents gives them an opportunity to learn as well. Involving other family members allows them to participate in learning and decision-making, which can lead to permanent improvements in nutrition and health practices within the entire family. When the family is not included in the educational process, the children may feel caught between what they learn in a class or program, and the practices they experience at home.
An investigation of the potential of high performance liquid chromatography for the comparison of soil samples

A simple presumptive test for the comparison of soil samples, namely the high performance liquid chromatographic comparison of the acetonitrile extract of soil, appears promising. Soils taken from different areas had different chromatograms. Soil taken from the same area had similar chromatograms. The chromatographic profile of one soil sample remained constant over a period of seven weeks.
Path-integral quantum Monte Carlo study of a mixture of Bose–Einstein condensates

Two-species hard-core bosons trapped in a three-dimensional isotropic harmonic potential at finite temperature are studied with the path-integral quantum Monte Carlo simulation. The double condensates show two distinct structures depending on how the external potentials are set. We find that the heavier particles form an outer shell with an identical external potential for both species, whereas the lighter particles form an outer shell with the same trapping frequency. Phase separation is observed in both the spatial and energy spaces. We provide physical interpretations of these phenomena and suggest future experiment to confirm these findings.
Synapses Between Corticotropin-Releasing Factor-Containing Axon Terminals and Dopaminergic Neurons in the Ventral Tegmental Area Are Predominantly Glutamatergic

Interactions between stress and the mesocorticolimbic dopamine (DA) system have been suggested from behavioral and electrophysiological studies. Because corticotropin-releasing factor (CRF) plays a role in stress responses, we investigated possible interactions between neurons containing CRF and those producing DA in the ventral tegmental area (VTA). We first investigated the cellular distribution of CRF in the VTA by immunolabeling VTA sections with anti-CRF antibodies and analyzing these sections by electron microscopy. We found CRF immunoreactivity present mostly in axon terminals establishing either symmetric or asymmetric synapses with VTA dendrites. We established that nearly all CRF asymmetric synapses are glutamatergic, insofar as the CRF-immunolabeled axon terminals in these synapses coexpressed the vesicular glutamate transporter 2, and that the majority of CRF symmetric synapses are GABAergic, insofar as the CRF-immunolabeled axon terminals in these synapses coexpressed glutamic acid decarboxylase, findings that are of functional importance. We then looked for synaptic interactions between CRF- and DA-containing neurons, by using antibodies against CRF and tyrosine hydroxylase (TH; a marker for DA neurons). We found that most synapses between CRF-immunoreactive axon terminals and TH neurons are asymmetric (in the majority likely to be glutamatergic) and suggest that glutamatergic neurons containing CRF may be part of the neuronal circuitry that mediates stress responses involving the mesocorticolimbic DA system. The presence of CRF synapses in the VTA offers a mechanism for interactions between the stress-associated neuropeptide CRF and the mesocorticolimbic DA system.
In-plane velocity encoding with coherent steady-state imaging.

Standard phase-contrast flow quantification (PC-FQ) using radiofrequency (RF) spoiled steady-state (SS) incoherent gradient-echo sequences have a relatively low signal-to-noise ratio (SNR). Unspoiled SS coherent (SSC) gradient-echo sequences have a higher intrinsic SNR and are T2/T1 weighted so that blood has a relatively large signal compared to other tissues. An SSC sequence that was modified to allow in-plane velocity encoding is presented. Velocity encoding was achieved by inverting the readout gradients. This offers the benefit that there is no resultant increase in repetition time (TR), which avoids increased sensitivity to off-resonance artifacts when conventional velocity-encoding methods using separate velocity-encoding gradients are extended to SSC sequences. The results of standard PC-FQ and the new method from in vitro experiments of constant and sinusoidal flow, and in vivo imaging of the carotid artery were compared. Vector field maps and paths obtained from particle-tracking calculations based on the velocity-encoded images were used to visualize the velocity data. The technique has the potential to increase the precision of PC-FQ measurements. Magn Reson Med 54:138–145, 2005. © 2005 Wiley-Liss, Inc.
A gas‐phase study of ligand effects on the reactivity of organometallic distonic ion Fe(p‐benzyne)+˙

This paper reports a gas-phase study of ligand effects on the reactivity of the organometallic distonic ion Fe(p-benzyne)+·. New organometallic distonic ions are generated by introducing a benzene ligand onto the metal center of Fe(p-benzyne)+·. We were interested in whether the reactivity of the radical site would be enhanced by ‘covering’ the metal center with extra ligands, i.e. by forming (benzene)Fe(p-benzyne)+·, since, in general, attachment of ligands reduces the reactivity of the metal center. For comparison, ions formed by attaching the same ligand to Fe(o-benzyne)+ and Fe(phenyl)+ were also studied. Reacting Fe(p-benzyne)+·, Fe(o-benzyne)+ and Fe(phenyl)+ directly with benzene generates, presumably, (benzene)Fe(p-benzyne)+·, (benzene)Fe(o-benzyne)+ and (benzene)Fe(phenyl)+, respectively. With allyl iodide, isopropyl iodide and dimethyl disulfide, (benzene)Fe(p-benzyne)+· reacts differently from its even-electron isomer, (benzene)Fe(o-benzyne)+, and its phenyl analogue, (benzene)Fe(phenyl)+. Furthermore, the results from these ion-molecule reactions and collision-induced dissociation of selected product ions indicate that the charge site and the radical site of (benzene)Fe(p-benzyne)+· interact with the neutral simultaneously and that the attachment of the benzene ligand does enhance the reactivity of the radical site to some extent. Copyright­© 1999 John Wiley & Sons, Ltd.
Low-field anomaly in 2D hopping magnetoresistance caused by spin-orbit term in the energy spectrum.

We demonstrate that a $k$-linear spin-orbit term ${\stackrel{^}{H}}_{\mathrm{SO}}$ in the Hamiltonian of a 2D electron, causing a minimum in the energy spectrum at finite $k={k}_{0}$, changes the low-field dependence of magnetoresistance from $\ensuremath{\delta}R(B)\ensuremath{\propto}\ensuremath{-}|B|$ to $\ensuremath{\delta}R(B)\ensuremath{\propto}\ensuremath{-}\frac{1}{2}(|B\ensuremath{-}{B}_{0}|+|B+{B}_{0}|\ensuremath{-}2{B}_{0})$, where ${B}_{0}=\frac{{k}_{0}^{2}{\ensuremath{\Phi}}_{0}}{\ensuremath{\pi}}$ is an effective field generated by ${\stackrel{^}{H}}_{\mathrm{SO}}$. The anomaly is suppressed by orienting electron spins in the plane with a strong parallel magnetic field.
Sleep, Psychosocial Functioning, and Device-Specific Adjustment in Patients with Implantable Cardioverter Defibrillators (ICDs)

Rates of sleep disorders and associated adjustment were examined in patients with implantable cardioverter defibrillators (ICDs; n = 42; Mage = 61.57, SD = 12.60). One night of ambulatory polysomnography, 14 days of sleep diaries, and questionnaires (mood, sleepiness, fatigue, device acceptance) were administered. Controlling for ischemia, MANCOVA examined adjustment by sleep diagnosis. Apnea was most common (28.6%), followed by Insomnia (16.7%) and Comorbid Insomnia/Apnea (11.9%). Patients with insomnia reported poorer mood, greater sleepiness, and lower device acceptance than good sleepers; they also demonstrated poorer mood and less ICD device acceptance than patients with sleep apnea. Patients with comorbid insomnia/apnea also exhibited poorer mood and less ICD device acceptance than good sleepers; however, comorbid patients did not significantly differ from insomnia or apnea patients on any measure. Those with disordered sleep (regardless of type) reported greater fatigue than good sleepers. Assessment (and treatment) of difficulties with sleep, mood, fatigue, and device acceptance may be important for the comprehensive clinical management of ICD patients. Further research appears warranted.
ALTERATIONS IN LUNG MECHANICS AND THE WORK OF BREATHING OF PRETERM LAMBS ON POSITIVE END EXPIRATORY PRESSURE (PEEP)

The effect of PEEP on lung mechanics and on the work of breathing was studied in 8 preterm lambs delivered by cesarean section at 134 days gestation. Indwelling arterial, venous, and tracheal cannulae were placed before clamping the cord. Assisted mechanical ventilation was performed at a tidal volume of 15/ml/Kg and a rate of 30-40/min at FIO2 of 0.95. Measurements of intraesophageal and tracheal pressures, air flow, tidal volume, and functional residual capacity enabled calculation of dynamic compliance (CL), specific compliance (CS), inspiratory resistance (RI), expiratory resistance (RE), and work of breathing at 0, 3, 6, and 10 cm H2O PEEP. Dynamic compliance and CS decreased by 0.11 ml/cm H2O/Kg and 0.0051 1/cm H2O per cm H2O PEEP respectively for PEEP above 3 cm H2O. Functional residual capacity increased (p<0.005) by 1.6 ml/Kg per cm H2O PEEP. Inspiratory resistance increased significantly (p<0.05) only between 0 and 6 cm H2O PEEP while RE increased (p<0.05) between 0 and all higher levels of PEEP (3, 6, and 10 cm H2O). As compared to 0 cm H2O PEEP (11.9 ± 2.5 SE × 106 ergs/min), the work of inspiration per unit time decreased 17% at 3 cm H2O and increased 10% and 80% at 6 and 10 cm H2O PEEP respectively. These data suggest that it is mechanically easier to breathe at low levels of PEEP (3 cm H2O) than without PEEP or at high levels of PEEP (10 cm H2O).(Supported by USPHS Grants HL19402 & HL15061)
Two algorithms for frequency domain design of robust control systems

Two algorithms are described that are useful in the computer-aided design implementation of the robust controller design scheme proposed by Horowitz (1963) and Horowitz and Sidi (1972).
Efficient method for fatigue based shape optimization of the oil sump carrying a differential case in four wheel drive vehicles

This paper presents an efficient method to improve the minimum fatigue safety factor in a complicated mechanical system using fatigue based shape optimization. The effect of shape optimization on the probabilistic response of the minimum fatigue safety factor was studied as well. The example used for this purpose is the oil sump of a four wheel drive vehicle carrying a differential case by four bolt connections. The conventional method for such a design improvement problem is based on the stress analysis in ABAQUS and the fatigue analysis in FEMFAT. In the proposed method, a submodel of the original ABAQUS finite element model was built for OPTISTRUCT using a MATLAB script. Fatigue based shape optimization for the most critical differential case bolt connection region was performed in OPTISTRUCT. The optimum shape found using the submodel was tested by replacing it back into the original ABAQUS and FEMFAT models. The proposed method was successful in finding out efficiently the optimum shape that maximizes the fatigue life. Probabilistic analysis was performed for the minimum fatigue safety factor considering the statistical variation of the clamping forces of the four differential case bolts using Optimal Latin Hypercube design of experiment, response surface model and Monte Carlo simulation techniques in ISIGHT. The design with the optimized shape was found to be robust against the variation of the clamping forces of the four differential case bolts.
Investigations on the near surface dose for three 10-MV x-ray beam accelerators with emphasis on the reduction of electron contamination.

A study of three 10‐MV x‐ray clinical accelerators with emphasis on the reduction of electron contamination was conducted. This study, which was performed with different types of trays and filters, suggests that, at 100‐cm source–surface distance (SSD), Pb can be used as an effective filter material up to 30×30 cm2; however, due to its transparency, a Clear‐Pb tray is useful for field sizes up to a 20×20 cm2. Percent depth doses for a few selected depths and field sizes at this nominal SSD were examined. No significant differences, with the exception of the location of D max, amongst the three accelerators were noticed.
Polymer flow in the clearance between closely spaced candle filter elements

A mathematical model for polymer flow in the clearance between high-resistance filter elements is developed. An analytical solution is obtained for pressure and velocity profiles for Newtonian fluids. A numerical solution is obtained for elastic fluids displaying power-law behavior in viscosity and entrance pressure loss. Elasticity of the polymer melt or solution is shown to be a significant factor in, determining these profiles. An example of the model's application, using rheological data for a commercial polyethylene, is given, and the impact of clearance flow pressure losses on the mechanical side loading of the filter elements is discussed.
Arginine Movement in Synergistic Coupling of Substrate and Ion Binding to Glutamate Transporter Homologue

Glutamate transporters are membrane pumps, which catalyze reuptake of the neurotransmitter from the brain synapses driven primarily by symport of sodium ions. A bacterial homologue, GltPh is a sodium/aspartate symporter, for which the crystal structures of sodium and substrate bound states have been determined. The thermodynamic studies have demonstrated that binding of sodium ions and aspartate to the transporter are coupled, such that the affinity for the substrate is much higher in the presence of the ions and vice versa. However, the ions are not directly coordinated by the substrate and the molecular mechanism of coupling remains largely unknown. Arginine 397 interacts with the side chain carboxylate of the substrate in the transporter crystal structures, is highly conserved among glutamate transporters, and has been shown in functional studies to be a key residue for substrate binding in mammalian homologues. To probe how the formation of the substrate-binding site affects sodium binding, we generated R397A mutant. We show that, as expected, R397A mutant has a low substrate affinity even in the presence of 100 mM sodium, measured by the isothermal titration calorimetry. Remarkably, in the absence of aspartate the sodium binding affinity for R397A is increased by ∼10 fold, compared to the wild type transporter, as measured by a fluorescence assay in vitro. Furthermore, substrate does not significantly increase the affinity of the mutant transporter for the ions. We suggest that arginine 397 in the wild type GltPh interferes with the sodium binding site or sites in the absence of the substrate and that its re-orientation upon substrate coordination relieves this interference. We hypothesize that these events are key to the mechanism of the allosteric coupling between substrate and ion binding.
A Standardized Method and Analytical Approach for Predicting Female Reproductive Stage in Teleosts by Using Ovary Color and Female Characteristics

Abstract Determining and understanding patterns in the reproductive status of fishes are essential for assessing individual and population reproductive potential. The least biased method for determining reproductive stage is through the use of ovarian histology; however, this method can be time consuming and expensive. To overcome these restrictions, we developed models to predict the reproductive stage of female striped bass Morone saxatilis by using ovary color and other female characteristics. We provide a standardized and calibrated method for quantifying ovary color, and we outline an analytical approach that utilizes binary and ordinal logistic regression. Our results indicated that binary models had high accuracy (<6% error) in distinguishing between the regressing phase (i.e., recently spawned) and the nonregressing phase (i.e., all other reproductive phases); we found even better accuracy (4% error) for ordinal models in discriminating among four nonregressing reproductive phases. All of the best...
Pearls and Pitfalls of Community-Based Group Interventions for Adolescents: Lessons Learned from an Adolescent Asthma Camp Study

This paper explores specific challenges in implementing community-based group interventions with adolescents and makes practical suggestions to researchers who contemplate the group approach. Group interventions have important implications for adolescent research and program development in the area of chronic illness. They have a capacity to address participants' psychosocial needs as well as to offer a cost and time-effective opportunity for disease-specific education. A group intervention encompasses an array of pragmatic challenges that need to be addressed through meticulous preparation. Based on the authors' firsthand experience with a group intervention for adolescents with asthma, this paper describes potential difficulties and logistics pertaining to recruitment, planning and implementation of a group intervention targeting adolescents and suggests general strategies that can be adopted.
Nomimoscolex touzeti n. sp. (Cestoda), a parasite of ceratophrys cornuta (L.): first record of a monticellidae in an amphibian host

Nomimoscolex touzeti n. sp. is described from one Ceratophrys cornuta (L.) caught in Amazonian Ecuador. Its taxonomic relationships to the others species are discussed. This new species is characterized by a cortical position of vitellaria; by the presence in the uteroduct of conglomerates of 20-40 eggs; by a weak ovary width/proglottis width ratio; by ventral excretory canals anastomosed; by a powerful vaginal sphincter and by a long cirrus. N. touzeti is the first record of Monticellidae in an amphibian host.
Producer Welfare Consequences of Regulating Chemical Residues on Agricultural Crops: Maleic Hydrazide and Tobacco

A procedure is presented to calculate welfare consequences of chemical regulation from demand curves when input applications are unobserved, and is applied to maleic hydrazide and tobacco. The relationship between chemical residues and weather variables and prices is estimated, and from this we derive demand curves using an application-residue relationship estimated using research station data. Chemical price levels required to attain given regulatory goals are estimated. Yearly producer losses from a chemical ban range from $6 million to $14 million, two to five times greater than from a tax achieving a 95% assurance rate of residues falling below a proposed
Planar laser-induced fluorescence imaging of flame heat release rate

Local heat release rate represents one of the most interesting experimental observables in the study of unsteady reacting flows. The direct measure of burning or heat release rate as a field variable is not possible. Numerous experimental investigations have relied on inferring this type of information as well as flame-front topology from indirect measures that are presumed to be correlated. A recent study has brought into question many of the commonly used flame-front marker and burning-rate diagnostics. This same study found that the concentration of formyl radical offers the best possibility for measuring flame burning rate. However, primarily due to low concentrations, the fluorescence signal level from formyl is too weak to employ this diagnostic for single-pulse measurements of turbulent-reacting flows. In this paper, we describe and demonstrate a new fluorescence-based reaction-front imaging diagnostic suitable for single-shot applications. The measurement is based on taking the pixel-by-pixel product of OH and CH2O planar laser-induced fluorescence (PLIF) images to yield an image closely related to a reaction rate. The spectroscopic and collisional processes affecting the measured signals are discussed, and the foundation of the diagnostic, as based on laminar and unsteady flame calculations, is presented. We report the results of applying this diagnostic to the study of a laminar premixed flame subject to an interaction with an isolated line-vortex pair.
Sleep apnea and adverse pregnancy outcomes: Chen et al

176 American Journal of Obstetrics & Gynecology A t least 18 million adults in the United States have sleep apnea; most of them, the obstructive variety. During sleep, those afflicted temporarily stop breathing for 10 seconds or more. These gaps, caused by narrowing or closure of the airway, can occur as often as 30 or more times per hour. Consequences range from daytime sleepiness, irritability, and headache to increased risk for serious problems, such as arrhythmias, hypertension, myocardial infarction, and stroke. This month, Journal Club members discussed a study that examined the effects of obstructive sleep apnea (OSA) on pregnancy outcomes. In fact, researchers found that the disorder is associated with a greater chance for several adverse events, including preeclampsia and low birthweight. Participants agreed that the study addressed an important topic and was well done.
General library standards

Paul Evan Peters begins his discussion of library standards with a convincing argument that the acceptance by librarians of the need for order and standards is not a character flaw. Rather, in promoting the use of standards, librarians are efficiently forwarding their missions to build and organize collections and to make them accessible to their clients. Pointing out the economic realities of contemporary libraries, Peters further argues that standards are appealing because they help librarians to control costs.
Sensitivity analysis of stochastic dynamical systems

A new, efficient algorithm is developed for the sensitivity analysis of a general class of stochastic dynamical systems. The algorithm is based on an idea of the likelihood ratio method that utilizes a probability density information for the sensitivity analysis, and on the Fokker-Planck or Kolmogorov's forward equation for computing the evolution of probability densities. The ideas of stochastic sensitivity analysis and likelihood ratio method are presented and combined to derive the sensitivity of average values of the performance functional with respect to system parameters. The present algorithm avoids the time consuming Monte Carlo or stochasic simulations, and, instead, sensitivity gradients of the probability density function and performance functional are directly computed during single-run simulation.
XPS and IR study of X-ray induced degradation of PVA polymer film

Abstract The X-ray induced compositional modification of a solvent cast polyvinyl alcohol [PVA, -(CH 2 -HCOH) n -] polymer film was studied using X-ray photoelectron (XPS) and transmission infra-red (IR) spectroscopies. While the -CH 2 group was stable, the alcoholic -COH moiety was unstable under the X-ray beam (Mg K α radiation: 1253.6 eV) and reached continuosly to produce three new C(1s) peaks assignable to carbonyl C=O (oxidation), carboxylate -COO (oxidative chain scission) and ether C-O-C linkages (crosslinking, dehydroxylation). Transmission FT-IR spectra of X-ray treated films showed the carbonyl stretch at 1700 cm -1 and a loss of intensity in the O-H stretching mode near 3340 cm -1 . The results indicate that degradation occurs throughout the polymer bulk and is caused either directly, by X-ray photons, or by the secondary electrons generated within the polymer. The ease with which degration can be detected is sensitive to analyzer resolution, X-ray flux and precautionary measures.
Pressure dependence of the low-momentum phonon dispersion relation in liquid He 4

The pressure dependence of the low-momentum phonon dispersion relation in liquid $^{4}\mathrm{He}$ has been determined from an analysis of experiments on the interactions between sound waves and thermal phonons. Specifically, changes $\frac{\ensuremath{\Delta}C}{C}$ in sound velocity were studied in the frequency range 1-15 MHz for pressures $0\ensuremath{\lesssim}P\ensuremath{\lesssim}20$ atm, at temperatures $0.1\ensuremath{\le}T\ensuremath{\le}0.45$ K. The results were found to be in agreement with phonon dispersion, for small momenta, of the form $\ensuremath{\epsilon}=Cp(1+\ensuremath{\gamma}{p}^{2}\ensuremath{\cdots})$, with $\ensuremath{\gamma}$ positive at low pressures. At saturated vapor pressure, the present study yields a value $\ensuremath{\gamma}=(16\ifmmode\pm\else\textpm\fi{}1)\ifmmode\times\else\texttimes\fi{}{10}^{37}$ cgs; $\ensuremath{\gamma}$ decreases linearly with increasing density and reaches zero at a density corresponding to a pressure of \ensuremath{\sim} 18 atm.
Exploring the acceptability of biometrics and fingerprint technologies

A number of research propositions and hypotheses based on conceptual modelling testing biometric applications especially thumb printing, and positive assumptions of value-added CRM principles were investigated from a sample of semi-professional and professionals from the metropolitan section of Pittsburgh, PA. Through principal components and factor analysis via regression, hypothesis-testing results of testing the dependent variable thumbprint and its improvement in security over traditional methods on a number of factor scores-based independent constructs were found to be highly significant. Of the five independent variable constructs of Ease of Use, Current Application, Age/Maturity, Affordability, and Positive Attitude, the most important considerations of positively perceiving biometric technology for enhanced security applications were ease of use and age/maturity in accepting thumb-printing technology. As the development of these security-based technologies continue the initial acceptance seems to be based on positive experiences of such implementations in the workplace.
Assessment of α2 adrenergic autoreceptor function in humans: Effects of oral yohimbine

Administration of three oral doses of yohimbine (10 mg, 15 mg, 20 mg) to eight healthy subjects resulted in significant increases in plasma free 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG). The 15 mg and 20 mg yohimbine doses induced modest increases in systolic blood pressure and autonomic symptoms such as piloerection and rhinorrhea. Marked behavioral effects such as anxiety were not observed. These results indicate that determination of the plasma MHPG response to yohimbine may be of value in assessing alpha 2 adrenergic autoreceptor function in humans.
Use of the tarSys® for posterior lamellar grafting for lower eyelid malposition

Lower eyelid malposition is a common clinical finding encountered by the oculoplastic surgeon. We examine the short-term results with the use of the tarSys spacer graft for the correction of lower eyelid malposition. A retrospective chart review of one surgeon’s outcomes with use of tarSys spacer graft for lower eyelid malposition was conducted. Preoperative margin-to-reflex distance 2 (MRD2) ranged from 8 to 15 mm with a mean of 9.5 mm (±2.4 mm) and median 8.25 mm. Mean postoperative MRD2 was 6.2 (±3.4 mm) ranging from 4 to 17 mm with a median of 5.0 mm. Improvement in MRD2 averaged 3.33 (±2.07 mm), range −2 to 6 mm, and a median of 3.25 mm. Preoperative lagophthalmos ranged from 0 to 10 mm with mean 3.9 (±3.6 mm) and a median of 3.0 mm. Mean postoperative lagophthalmos was 1.3 (±1.5 mm) ranging from 0 to 4 mm with a median of 0.7 mm. Improvement in lagophthalmos averaged 2.5 (±2.7 mm). The tarSys spacer graft should be thought of as a dependable allogenic implant for posterior lamellar support when correcting lower eyelid malposition. Level of Evidence: Level V, therapeutic study.
A diode laser study of the Cl + CH3CO reaction

Real-time kinetic measurements are reported for the Cl + CH3CO CH2CO + HCl reaction. The experiments utilize infrared spectroscopy to determine the time dependence of the ketene formed via this reaction and of the CO produced from the subsequent rapid reaction between chlorine atoms and ketene. The reaction is investigated over a pressure range of 10–200 torr and a temperature range of 215–353 K. Within experimental error the rate constant under these conditions is k5a = (1.8 ± 0.5) × 10−10 cm3 s−1. We have also examined the Cl + CH2CO reaction and found it to have a rate constant of k6 = (2.5 ± 0.5) × 10−10 cm3 s−1 independent of temperature. © John Wiley & Sons, Inc. Int J Chem Kinet 29: 421–429, 1997.
The generation of intense radiofrequency fields in μcoils

Abstract Large amplitude radiofrequency (rf) fields hold great promise in wide line NMR where it becomes possible to excite the full breadth of the line in a quantitative fashion. Applications in quadrupole NMR and in NMR of paramagnetic systems benefit greatly from intense fields. Spin manipulations in multiple quantum NMR experiments, specifically, the generation of multiple quantum coherence in MQ NMR, are more efficiently produced using intense rf fields. In this work we describe a μcoil probe that produces an rf field of 25 MHz, more than five times larger than the greatest rf field reported in the literature. We accomplish this in a robust, 127 μm diameter solenoid coil using 1 kW of rf power.
A Hermit Crab New to Britain

OF recent years the hermit crab Clibanarius misanthropus (Risso) has been reported from stations successively farther north along the coast of the Bay of Biscay1. It seems probable that this represents a true northerly advance of this example of an essentially tropical genus, for it is unlikely to have been overlooked since its almost exclusively intertidal habit and its brilliant colours attract the attention. By 1957 it had been reported to the north of Brest, but it does not seem yet to have been found along the north French coast: in particular, the collectors of the Station Biologique at Roscoff have not found it. Indeed, Crisp and Fischer-Piette1 advance reasons for supposing that it is unlikely to spread along this coast. On the other hand, the drift of surface water which occurs in some years from Finistere towards Land's End or towards the Scilly Islands might be expected to carry larvae to the British shores. Despite regular surveys of the shores of the Scilly Islands, our colleagues have not found this species there; but during the early months of 1960 large numbers were found on the shore at Mousehole on the southern coast of Cornwall (lat. 56° 6′ N., long. 5° 31′ W.), near Land's End. It is significant that the water at the western end of the English Channel in March and April 1959 (when the larvae of C. misanthropus would be planktonic) had an unusually high salinity, suggesting the presence of Biscay water flowing into the Channel.
Evaluation of response time of a transcutaneous oxygen tension electrode.

Summary: Response characteristics of a transcutaneous PO2 electrode to step changes in PaO2 were determined. In vitro lag time and 95% response time of a transcutaneous PO2 monitor were compared to in vivo response. Release of arterial occlusion was used to produce rapid local Pao2 changes in human infants and adults. In vitro lag time and 95% response time varied according to whether an increment or decrement in PO2 was produced. In vivo 95% response time of this electrode was two to six times slower than previous estimates, and it varied significantly with the magnitude of the step change, subject age, anatomic location, and local hemodynamic factors. Also, we found that in vivo lag time is two to three times faster than previously reported. Speculation: Under steady-state conditions, transcutaneous PO2 correlates well with PaO2, but when rapid change is encountered as during oxygen administration or apnea, transcutaneous PO2 will significantly underestimate PaO2 change. On the other hand, the relatively short lag time suggests that the transcutaneous PO2 electrode may be useful in following rapid PaO2 changes qualitatively.