cssi/SciSciGPT-SciSciNet huggingface dataset:
β-Galactosidase: Inactivation of Its Messenger RNA by Ultraviolet Irradiation

A brief exposure of Escherichia coli cells to an indutcer for β- galactosidase results in the production of a messenger RNA which subsequently expresses itself as β-galactosidase. Ultraviolet irradiation of cells after exposure to the inducer results in a decrease in the amount of β-galactosidase formed. The messenger RNA formed during the brief exposure to inducer is evidently inactivated by the ultraviolet radiation. The decay of messenger RNA activity in irradiated cells has the same kinetics as that observed in unirradiated cells.
Both medial prefrontal and amygdala central nucleus lesions abolish heart rate classical conditioning, but only prefrontal lesions impair reversal of eyeblink differential conditioning

Rabbits with lesions of either medial prefrontal cortex (mPFC) or amygdala central nucleus (ACN) were compared with sham-lesioned animals during differential and reversal classical conditioning of the eyeblink (EB) and heart rate (HR) response. Lesions of the mPFC, but not ACN, produced a severe impairment in EB reversal conditioning, but neither lesion affected original discrimination. However, both mPFC and ACN lesions produced a severe attenuation of accompanying HR decelerations during both initial differentiation and reversal. These results suggest that mPFC processing of Pavlovian conditioning contingencies affects not only the autonomic component of learning but preservative somatomotor conditioning as well, whereas ACN processing affects only the autonomic component.
Implementation Of Eigenvector Methods

Efficient computational procedures are described for updating the spectral decomposition of a complex Hermitian matrix to which a matrix of rank one has been added. These methods will be useful in on-line implementation of high-resolution direction finding and beamforming algorithms.
Stress concentrations caused by bond cracks in single-lap adhesive composite joints

Abstract Nonlinear finite element analysis was used to study stress fields in single-lap adhesively bonded composite joints containing cracks of different lengths. It was shown that stresses, energy release rates, and stress intensity factors vary nonlinearly with the crack length. However, a near-linear dependence was observed between the stress intensity factors and the load for cracks of constant length. The analysis showed that the critical values of the energy release rates for fast crack propagation in the final stage of fatigue life were 2–3 times lower than the critical energies for the cracks propagating under quasi-static loading.
Epigenetic Modification of Histone 3 Lysine 27: MEDIATOR SUBUNIT MED25 IS REQUIRED FOR THE DISSOCIATION OF POLYCOMB REPRESSIVE COMPLEX 2 FROM THE PROMOTER OF CYTOCHROME P450 2C9*

The Mediator complex is vital for the transcriptional regulation of eukaryotic genes. Mediator binds to nuclear receptors at target response elements and recruits chromatin-modifying enzymes and RNA polymerase II. Here, we examine the involvement of Mediator subunit MED25 in the epigenetic regulation of human cytochrome P450 2C9 (CYP2C9). MED25 is recruited to the CYP2C9 promoter through association with liver-enriched HNF4α, and we show that MED25 influences the H3K27 status of the HNF4α binding region. This region was enriched for the activating marker H3K27ac and histone acetyltransferase CREBBP after MED25 overexpression but was trimethylated when MED25 expression was silenced. The epigenetic regulator Polycomb repressive complex (PRC2), which represses expression by methylating H3K27, plays an important role in target gene regulation. Silencing MED25 correlated with increased association of PRC2 not only with the promoter region chromatin but with HNF4α itself. We confirmed the involvement of MED25 for fully functional preinitiation complex recruitment and transcriptional output in vitro. Formaldehyde-assisted isolation of regulatory elements (FAIRE) revealed chromatin conformation changes that were reliant on MED25, indicating that MED25 induced a permissive chromatin state that reflected increases in CYP2C9 mRNA. For the first time, we showed evidence that a functionally relevant human gene is transcriptionally regulated by HNF4α via MED25 and PRC2. CYP2C9 is important for the metabolism of many exogenous chemicals including pharmaceutical drugs as well as endogenous substrates. Thus, MED25 is important for regulating the epigenetic landscape resulting in transcriptional activation of a highly inducible gene, CYP2C9.
Knowledge engineering in quantitative histopathology

Ongoing research on a system for the automated evaluation of digitized images of histopathologic sections is described. The system comprises an ultrafast laser scanner microscope capable of recording image data at 64 Mhz in each of two wavelength channels, and a multiprocessor computer containing thirty-six Motorola 68000 processing elements. The operating system allows an image-data-driven dynamic reconfiguration of the computer architecture; this reconfiguration is based on prior knowledge of the histopathologic sections to be processed. Knowledge engineering methods are used extensively as development tools in the development of an expert system-controlled scene segmentation, processing task scheduling, in the diagnostic expert system module, and its validation procedures.
Study of carrier generation in phthalocyanines by time-resolved fluorescence

We have studied the influence of electric field on fluorescence in particles of photoconductive TiOPc (I), TiOPc (IV), HOGaPc, and x-H 2 Pc dispersed in a polymer matrix. Electric field induced quenching of both the integrated and time-resolved fluorescence were measured. Time-resolved fluorescence decays were analyzed by fitting the data to a sum of two exponentials, representing the fast and slow fluorescence components. For HOG a Pc, TiOPc(I), and TiOPc (IV), the fast fluorescence component exhibits both amplitude and lifetime quenching. These results indicate that carrier generation in HOGaPc, TiOPc(I), and TiOPc (IV) originates from both relaxed and nonrelaxed intrinsic excited singlet states, while the trapped excitons do not lead to significant carrier production. In contrast, for x-H 2 Pc, significant amplitude quenching of the fast component is observed only at high field, and the trapped excitons are an important source of photogenerated carriers. This indicates that x-H 2 Pc possesses at least some bulk-sensitized photocarrier generation. All of the phthalocyanines studied exhibited a quadratic dependence of integrated fluorescence quenching on electric field, indicating the existence of a neutral carrier precursor state.
Diversity Arrays For Optical Communications Through Atmospheric Turbulence

Motivation for the use of spatial diversity arrays in both direct detection and optical' heterodyne communications receivers in the presence of atmospheric turbulence is discussed. Procedures for specifying optimum receiver structures are described and the statistical characterization of the received field necessary for utilizing these procedures is presented.
Coccidioidomycosis: A review and update

Coccidioidomycosis occurs in arid and semi-arid regions of the New World from the western United States to Argentina. Highly endemic areas are present in the southwest United States. Coccidioides species live in the soil and produce pulmonary infection via airborne arthroconidia. The skin may be involved by dissemination of the infection, or by reactive eruptions, such as a generalized exanthem or erythema nodosum. Interstitial granulomatous dermatitis and Sweet's syndrome have recently been recognized as additional reactive signs of the infection. Coccidioidomycosis is a "great imitator" with protean manifestations. Cutaneous findings may be helpful clues in the diagnosis of this increasingly important disease.
Mental representations of spatial relations.

Abstract Three classes of theories of the mental representation of spatial relations were tested. Nonhierarchical theories propose that spatial relations among objects in an environment are mentally represented in networks or in imagelike, analog formats. The distinctive claim of these theories is that there is no hierarchical structure to the mental representation. Hierarchical theories , on the other hand, propose that different “regions” of an environment are stored in different branches of a graph-theoretic tree. These theories can be divided into two classes of subtheories depending on the kinds of relations encoded in memory: Strongly hierarchical theories maximize storage efficiency by encoding only those spatial relations needed to represent a layout accurately; partially hierarchical theories predict redundancy in the representation, such that many spatial relations that can be computed also will be stored explicitly. These three classes of theories were tested by having subjects learn the locations of actual objects in spatial layouts or the locations of objects on maps of those layouts. Layouts and maps were divided into regions with transparent boundaries (for the layouts, string on the floor; for the maps, lines). After learning the layouts or maps, subjects participated in three tasks: item recognition, in which the variable of interest was spatial priming; direction judgments; and euclidean distance estimation. Results from all three tasks were sensitive (a) to whether objects were in the same region or in different regions and (b) to the euclidean distances between pairs of objects. These findings were interpreted as supporting partially hierarchical theories of spatial representations. Computer simulations supported this conclusion.
An Indirect Method of Forming Expressions for the Inverses of Genetic Variance-Covariance Matrices for Two Traits

Abstract Practical application of best linear unbiased prediction procedures to large data sets requires efficient use of computer time and storage. One way to increase effiency of computer use is to eliminate extraneous equations, i.e., equations for genetic predictions that are of no or little practical value. Rules are derived for obtaining, by inspection of the pedigree, a matrix representing the inverse of the genetic variance-covariance matrix for two traits in which all genetic values are not represented. The need to form the genetic variance-covariance matrix itself is eliminated. The condition in which the expression is the exact inverse is specified. An illustration is provided. Inbreeding is not considered.
Green Oxidation of Menthol Enantiomers and Analysis by Circular Dichroism Spectroscopy: An Advanced Organic Chemistry Laboratory

Green chemistry addresses environmental concerns associated with chemical processes and increases awareness of possible harmful effects of chemical reagents. Efficient reactions that eliminate or reduce the use of organic solvents or toxic reagents are increasingly available. A two-week experiment is reported that entails the calcium hypochlorite oxidation of menthol to menthone. The experiment enhances student interest, knowledge, and techniques in organic chemistry, while promoting the development of socially responsible citizens. The experiment is suitable for an advanced organic chemistry laboratory. The first objective of this experiment is to perform an oxidation reaction that uses environmentally friendly, nonhazardous, and cost-effective reactants. A second objective is to introduce circular dichroism spectroscopy, a powerful analytical technique typically overlooked in the undergraduate curriculum. The students also gain experience in IR and NMR spectroscopies.
Special Issue on Remote Sensing of Building Interior

The 15 papers in this special issue focus on remote sensing of building interior and can be categorized into: 1) system design and instrumentation; 2) advanced imaging techniques for elimination of glint from large flat wall structures; 3) radar polarimetry; 4) passive microwave radiometry; 5) advanced forward models based on high-frequency methods as well as full-wave solutions based on finite-difference time-domain technique for large-scale problems; and 6) detection and identification techniques of behind the wall stationary and moving concealed and unconcealed targets.
Effect of wall radiation on thermal instability in a vertical cylinder

Abstract Wall heat radiation in a long vertical cylinder heated from below increases critical Rayleigh number by up to a factor of three. The analysis presented explains why initiation of natural convection in a gas-filled honeycomb structure occurs at a Rayleigh number higher than that necessary when the same honeycomb is filled with an infrared-opaque liquid.
Chemical dynamics of enriched mantle in the southwestern United States: Thorium isotope evidence

Abstract As probes of mantle below continents, geographically dependent isotope signatures in basalts suggest preservation of old and chemically enriched lithospheric domains. In this paper, we show that Th isotope compositions of basalts from the southwestern United States further delimit possible models for the origin and consequences of this enrichment. The data presented are for a compositionally diverse suite of largely mafic lavas from the central Basin and Range (CBR). The range of initial Th isotope signatures ( ( 230 Th) ( 232 Th) = 0.65−1.10 ) in these continental basalts overlaps and extends that of ocean island basalts. Pairing Th isotope variations with those of Nd provides a potent means of discriminating between various models for generation of enriched chemical signatures in continental basalts and precludes the possibility that the CBR basalts acquired their enriched chemical and isotopic signatures during ascent through the lithosphere. CBR basalts exhibit a negative co-variation between Nd and Th isotope ratios that is difficult to reconcile with assimilation because Nd concentrations in appropriate lower crustal lithologies are too low to decrease significantly the Nd isotope signatures from those of depleted mantle basalts. Nd Th  Th U systematics and a lack of Th U fractionation similarly offer little support for contamination of asthenospheric melts by small volume melts generated in the mantle lithosphere. Most CBR lavas have ( 230 Th) ( 238 U) . These modest Th enrichments reflect the probable contribution of metasomatic phases to alkaline lavas and the higher melt fractions of subalkaline lavas. Enriched mantle sampled by CBR basalts has higher Pb Nd as well as time-integrated and present-day Th U than most of the sub-oceanic mantle, confirming the critical role that long-term isolation of continental lithosphere has on the development of chemical signatures distinct from those of convecting upper mantle. Coupled PbTh isotope characteristics in CBR basalts are consistent with progressive isolation of increasingly U-enriched mantle.
On the modeling of hyperspectral imaging data with elliptically contoured distributions

Accurate statistical models for hyperspectral imaging (HSI) data are fundamental for many subsequent applications including detection, classification, and estimation. Suppose the whole nonhomogeneous HSI data is well classified into homogeneous unimodal clutters, we find that the family of elliptically contoured distributions (ECDs) is capable of providing sufficiently accurate model for each clutter. In this paper, several techniques are applied to test the elliptical symmetry of HSI clutters. Instead of testing elliptical symmetry directly, its counterpart spherical symmetry is examined for the whitened unimodal clutters. For each clutter which passes these symmetry checking tests, fitting an appropriate ECD based model to the data can be done in the Mahalanobis distance direction.
Oxygen Delivery from Hyperbarically Loaded Microtanks Extends Cell Viability in Anoxic Environments

Oxygen diffusion limitations within nascent tissue engineered (TE) grafts lead to the development of hypoxic regions, cell death, and graft failure. Previous efforts have been made to deliver oxygen within TE scaffolds, including peroxide-doping, perfluorocarbons, and hyperbaric oxygen therapy, to mitigate these effects and help maintain post transplantation cell viability, but these have suffered from significant drawbacks. Here we present a novel approach utilizing polymeric hollow-core microspheres that can be hyperbarically loaded with oxygen and subsequently provide prolonged oxygen delivery. These oxygen carriers are termed, microtanks. With an interest in orthopedic applications, we combined microtanks within polycaprolactone to form solid phase constructs with oxygen delivery capabilities. The mathematical laws governing oxygen delivery from microtank-loaded constructs are developed along with empirical validation. Constructs achieved periods of oxygen delivery out to 6 days, which was shown to prolong the survival of human adipose derived stem cells (hASCs) and human umbilical vein endothelial cells (HUVECs) as well as to enhance their cellular morphology under anoxic conditions. The results of this study suggest the microtank approach may be a feasible means of maintaining cell viability in TE scaffolds during the critical period of vascularization in vivo.
Procedure for Study of Reality Testing in Schizophrenics

Perky's (1910) method of studying perception and imagery was adapted to study reality testing in schizophrenia. 10 schizophrenic and 10 non-schizophrenic Ss were seen in 2 identical sessions during which they were asked to differentiate between sounds they imagined and sounds they heard through earphones. The schizophrenic Ss, although reporting fewer images, manifested more perceptual distortions and more misperceptions of actual sounds as images. The procedure described seems to hold promise as both a research tool and a diagnostic technique for assessing reality testing in the laboratory.
A contribution to the cell-physiologic analysis of growth and morphogenesis in fern prothallia

The cell physiologic investigations on the analysis of growth and morphogenesis of the prothallia ofDryopteris parasitica brought the following results:
Histomoniasis in gnotobiotic chickens and turkeys: Biological aspects of the role of bacteria in the etiology

Abstract The bacterial requirements for producing infectious enterohepatitis in bacteria-free chickens were different from those for the disease in bacteria-free turkeys. When both Escherichia coli and Clostridium perfringens were introduced with Histomonas meleagridis, mild atypical cecal lesions were produced in 3 of 28 chickens while typical liver and cecal lesions were both present in all of 25 turkeys. When single species of bacterial agents were used, the rate of infection was less. More lesions were produced with C. perfringens than with E. coli. The cecal bacterial flora of conventional chickens, when introduced into bacteria-free chickens, fulfilled the requirement of H. meleagridis for induction of infectious enterohepatitis. Attempts to define the specific bacteria involved in the etiology of the disease in chickens from among 48 different bacterial isolates and Candida albicans were unsuccessful, although very mild disease was produced inconsistently with various combinations of strains of E. coli with Pseudomonas aeruginosa and Streptococcus faecalis or with C. perfringens. Eimeria adenoides, a cecal coccidium, survived when introduced with Histomonos-infected Heterakis eggs into bacteria-free turkeys and supported the growth of some histomonads but not Heterakis gallinarium larvae. Eimeria adenoides did not simulate the role of bacteria in producing infectious enterohepatitis. Disease was produced and Heterakis larvae did survive in conventional turkeys receiving E. adenoides and infected Heterakis eggs. The essential contributing factor of bacteria in the pathogenesis of infectious enterohepatitis was determined to be neither a favorable pH nor an oxidation-reduction potential value within the intestine of the host. The oxidation-reduction potential of bacteria-free cecal contents was strongly positive, that of the conventional chicken with its indigenous microflora was strongly negative, while the potential of the contents of ceca with infectious enterohepatitis was intermediate. The pH of the bacteria-free cecum closely approximates that of the parasite-infected intestine, while the pH of the uninfected conventional cecum was somewhat lower. In the pathogenesis of infectious enterohepatitis, the role of bacteria apparently was more vital for the survival of Heterakis than Histomonas.
Polynomial enumeration of multidimensional lattices

Denoting the nonnegative (resp. signed) integers byN (resp.Z) and the real numbers byR, letK ⊂ Rm andf: Rm→ R. Thenf is astoring function (resp.packing function) onK wheneverf|(Zm⊒ K) is an injection into (resp. bijection onto)N. Unit translations gm of some P. Chowla [1961] polynomials are packing functions on the correspondingNm, and all compositions of these polynomials yield further packing functions on variousNr. We study this accessible family of packing functions, using standard properties ofordered trees to classify all those compositions, up to a simple equivalence, which define polynomial packing functions on eachNm. The numberc(m) of equivalence classes is an exponentially growing function for largem, whence the uniqueness conjecture of our prior two-dimensional work has no counterpart for largerm. We obtain the admissible degrees for composition polynomials inm variables; we describe the tre structures for all such polynomials with extremal degrees. Them-variable polynomials of least degree form a rather irregular numbera(m) of equivalence classes. Density considerations give some degree constraints on ageneral polynomial packing function whose domainK is the topological closure of a nonvoid open cone.
Protective immunity against clinical sarcocystosis in cattle

Five experiments involving 50 calves (Bos taurus) were conducted to determine if oral infection with sporocysts of the pathogen Sarcocystis cruzi or the non-pathogen Sarcocystis hirsuta would stimulate development of a protective immunity against illness or death from challenge infection with large numbers of S. cruzi sporocysts. Four experiments involved Holstein calves housed in individual pens in isolation buildings; one experiment involved Hereford calves on an open range. Calves infected with 50 000 to 100 000 S. cruzi sporocysts were protected from illness and death that would have resulted from challenge infections with 250 000 or 500 000 S. cruzi sporocysts given 70-252 days later. Calves treated with the anticoccidial drug amprolium from 21 to 35 days after being given an immunizing infection with S. cruzi to reduce clinical signs of the immunizing infection were also protected. Non-immunized calves and those given S. hirsuta sporocysts were not protected.
The Sea Floor: An Introduction to Marine Geology

The authors of the second edition of The Sea Floor: An Introduce on to Marine Geology are to be commended for providing an easily readable book on marine sedimentology, its history, and its profound foundations for interdisciplinary research. The explosive growth of marine geological research and knowledge during the last 2 decades could easily overwhelm anyone wishing to summarize it. The authors acknowledge this in their preface: “We attempted neither a balanced nor an encyclopedic survey,” and this is clearly evident in this 356-page tome with numerous figures and appendices. The book concentrates on sedimentary marine geology, with only enough geophysics and igneous petrology necessary to place scientific hypotheses in context.
Craft and the Limits of Skill: Handicrafts Revivalism and the Problem of Technique

Skill and technique appear axiomatic to the definition of handicraft. And no designers are more closely associated with defending skilled human labour than the leaders of the Arts and Crafts Movement in England and America. This essay, however, proposes that industrial-era definitions of handicraft—originating with figures such as T. J. Cobden-Sanderson, William Morris, Gustav Stickley and even the sociologist Thorstein Veblen—are in fact predicated on a paradoxical relationship to skill. For if skilled labour seems the self-evident alternative to mechanical production, it is also true that machines, capable of absolute precision and uniformity, threaten the traditional associations of craft and perfect workmanship. The era of the Arts and Crafts Movement thus developed ways of thinking about craft that are sceptical of practised, learned or reproducible technique. This essay probes the implications of that epistemological shift, considering its effects on the aesthetics of craft, on the class dynamics of handicrafts revivalism and on the popularization of a medieval style (rather than, say, eighteenth-century models) as the paradigm of the handcrafted. Rethinking the relation of craft and skill, the article offers an alternative to established historiographical models in which practical skilled labour was steamrolled by shoddy industrial production or modern marketplace ideals. Instead, I suggest that industrial-era definitions of skill do not support conventional distinctions of craft and consumerism, practicality and rarity or simplicity and excess.
Direct Dynamics Simulations of the Reaction O+(4S) + HCN at Hyperthermal Collision Energies†

Direct dynamics classical trajectory simulations of the O+(4S) + HCN reaction at hyperthermal energies were performed based on the ground state PM3 potential energy surface, and the results have been used to interpret guided ion-beam experiments. This simulation exemplifies the complex chemistry and dynamics that can happen in hyperthermal ion−molecule reactions. Calculations were carried out at various collision energies ranging from 2 to 15 eV with emphasis on energies higher than 5 eV. All the energetically accessible reaction channels were found, including the HCO+/HOC+, NO+, and CO+ ions reported in the experiment. OCN+ and CN+ were found to be negligible at high energies. Relatively lightweight ions, NH+, CH+, and OH+, which are energetically accessible on both quartet and doublet potential surfaces but which were not reported in the experiment, are found to have cross sections below 1 A2. The calculated excitation functions for NO+, HCO+, and CO+ agree with experiment qualitatively with quantitativ...
G-protein receptor kinase 3 (GRK3) influences opioid analgesic tolerance but not opioid withdrawal

Tolerance to opioids frequently follows repeated drug administration and affects the clinical utility of these analgesics. Studies in simple cellular systems have demonstrated that prolonged activation of opioid receptors produces homologous receptor desensitization by G-protein receptor kinase mediated receptor phosphorylation and subsequent β-arrestin binding. To define the role of this regulatory mechanism in the control of the electrophysiological and behavioral responses to opioids, we used mice having a targeted disruption of the G-protein receptor kinase 3 (GRK3) gene. Mice lacking GRK3 did not differ from wild-type littermates neither in their response latencies to noxious stimuli on the hot-plate test nor in their acute antinociceptive responses to fentanyl or morphine. Tolerance to the electrophysiological response to the opioid fentanyl, measured in vitro in the hippocampus, was blocked by GRK3 deletion. In addition, tolerance to the antinociceptive effects of fentanyl was significantly reduced in GRK3 knockouts compared to wild-type littermate controls. Tolerance to the antinociceptive effects of morphine was not affected by GRK3 deletion although morphine tolerance in hippocampal slices from GRK3 knockout mice was significantly inhibited. Tolerance developed more slowly in vitro to morphine than fentanyl supporting previous work in in vitro systems showing a correlation between agonist efficacy and GRK3-mediated desensitization. The results of these studies suggest that GRK3-mediated mechanisms are important components of both electrophysiologic and behavioral opioid tolerance. Fentanyl, a high efficacy opioid, more effectively produced GRK3-dependent effects than morphine, a low efficacy agonist. British Journal of Pharmacology (2004) 141, 55–64. doi:10.1038/sj.bjp.0705595
UNUSUAL DIAGNOSES AMONG VIOLENT PATIENTS

Several medical disorders rarely cause violent behavior. When they do so, it is dramatic because the violence and other bizarre behaviors are not in keeping with the premorbid picture of the individual. Often, medical and neurologic symptoms are present, but occasionally psychiatric symptoms may present alone with the aggression and violence, which points out the importance of complete medical psychiatric evaluations of patients who present with recent histories of violent behavior. Most violence involves "horses," but the rare "zebras" should be kept in mind because they are often treatable.
Spatial Dispersion in Metallic Meta-materials

We investigate spatial dispersion in periodic meta-materials and its implication for NIMs. Three meta-materials are investigated for spatial dispersion: 2-D arrays of nanorods, nanoholes in a SiC membrane (experiment), and 3-D metallic mesh.
An Inquiry into Possible New Items of Background Information about TOEFL Candidates.

ABSTRACT Candidates taking the Test of English as a Foreign Language (TOEFL) are currently asked to supply several items of background information: birth date, sex, number of times TOEFL has been taken before, whether they are seeking status as undergraduate or graduate students, their native country and native language, and (for prospective graduate students only) their intended field of study. The candidates provide this information on one side of their answer sheet, according to instructions given in the handbook sent to each candidate,upon registration. In view of the extreme heterogeneity of the TOEFL candidate population it seims likely that additional information would be valuable. Foreign studeilts (39 . undergraduate and 18 graduate) were interviewed at four institutions. Four variables emerged as being the most promising: total number of years of formal study of English; reading of English-language newspapers, books, and magazine; number of years of father's education; and number of years of mother's education. Collectively, these variables offer the promise of enhanced research on variouq aspects of the TOEFL candidate population and on foreign studer generally. The appendices include the interview questions used in the study, as well as interviewees' comments on TOEFL. (PN)
Gel and free solution electrophoresis of variably charged polymers

To assess the role of charge density on polyelectrolyte mobility, both gel and free solution electrophoresis experiments are performed on poly(acrylic acid) and acrylic acid/acrylamide copolymers. Control of charge density for poly-(acrylic acid) is achieved through solution pH, while control for acrylic acid/ acrylamide copolymers is obtained through chain composition. In either approach, the effective fraction of charged repeat units can be varied from 0 to 100% without a major interruption of solvent quality. Polyelectrolyte mobility in the presence of a monovalent counterion is observed to rise linearly with charge density when this density is low. A transition to charge density independence then occurs over a surprisingly narrow window of charge density. For vinyl polymers of the sort examined here, the transition occurs when 35-40% of the repeat units are charged. These observations are qualitatively consistent with the free solution electrophoresis model proposed by Manning and several previous data sets. An unexpected overlap of normalized gel and free solution data reveals that the charge density exerts a comparable influence in either environment. Results from the present study help define the experimental conditions in which electrophoresis can provide polymer separation by charge density and those in which the method can provide polymer separation by molecular weight.
A Finite-volume/Boundary-element Method for Flow Past Interfaces in the Presence of Surfactants, with Application to Shear Flow Past a Viscous Drop

Abstract A finite-volume method is developed for solving the convection–diffusion equation governing the transport of an insoluble surfactant over a generally evolving fluid interface, using an unstructured triangular grid. The unstructured grid has significant advantages compared with a structured grid based on global curvilinear coordinates, concerning adaptability and ability to conserve the total amount of the surfactant. The finite-volume method is combined with a boundary-element method for Stokes flow to yield an integrated procedure that is capable of describing the evolution of an interface from a specified initial state. Several series of simulations of the deformation of a neutrally buoyant viscous drop suspended in an infinite simple shear flow, or a semi-infinite shear flow bounded by a plane wall are performed. The results for the infinite flow extend those presented previously for the particular case where the ratio of the drop viscosity to the ambient fluid viscosity, λ , is equal to unity. It is shown that the effect of surfactant transport on the drop deformation and on the effective rheological properties of a dilute suspension becomes increasingly more important as λ becomes smaller and the drop reduces to an inviscid bubble. For semi-infinite flow past a drop above a plane wall, it is found that interfacial stresses due to variations in surface tension facilitate the drop migration away from the wall.
Effects of ATP and metal ions on cytosol and nuclear phosphohistone phosphatases of rat liver

Abstract 1. 1. Rat liver cytosol and nuclear phosphohistone phosphatases have each been resolved into four fractions by DEAE cellulose chromatography. 2. 2. The enzymic response to varying concentrations of ATP and metal ions revealed marked differences among the enzyme fractions. 3. 3. Generally, the activities of the cytosol enzymes are stimulated by ATP and metal ions to a much greater extent than that of the nuclear enzymes. The results indicate that the phosphohistone phosphatase thus isolated from the cytosol and nucleus are different.
A simple culture system for juvenile lobsters

Abstract A simple, inexpensive modular system is described for raising juvenile lobsters. The system is constructed in modular fashion from Lucite racks and plastic trays. The tray size is increased as the lobster grows so that the system can accommodate a wide range of animal sizes.
Risk of anaphylaxis after reexposure to intravenous lepirudin in patients with current or past heparin-induced thrombocytopenia.

OBJECTIVE To retrospectively assess the signs and symptoms indicative of adverse reactions to repeated exposures to lepirudin in patients with heparin-induced thrombocytopenia who received at least 2 courses of lepirudin therapy. PATIENTS AND METHODS Medical records were retrospectively assessed from adult patients who received at least 2 courses of lepirudin therapy separated by at least 1 week between January 1999 and June 2002 at The Cleveland Clinic, Cleveland, Ohio. We evaluated the list of 289 low-level terms for possible signs and symptoms of anaphylactic reactions in the medical dictionary for regulatory activities as well as patient vital signs to detect manifestations of immediate hypersensitivity reactions. Vital signs from the day before initiation of lepirudin therapy were compared with those from days 1 and 2 after exposure. RESULTS No cases of anaphylaxis or allergic reaction related to lepirudin administration were identified among 43 adult patients. On day 1 of lepirudin, 10 patients had lower systolic blood pressures (by =20 mm Hg) than pre-lepirudin values, and 4 patients had systolic blood pressures of less than 100 mm Hg. CONCLUSIONS Isolated asymptomatic decreases in blood pressure after patient reexposure to lepirudin most likely do not reflect anaphylaxis due to lepirudin. We believe that isolated and uncommon cases of anaphylaxis temporally related to lepirudin exposure should not preclude its use in patients with heparin-induced thrombocytopenia and past lepirudin exposure.
Kinetic models for the synthesis of (U, Pu)O2−y by hydrogen-reduction and carbothermic techniques

Abstract Three models have been developed that permit the calculation of the time necessary for the synthesis of hypostoichiometric oxide from (U, Pu)O2. The models are based on the interrelation between oxygen potential, valence of plutonium, and temperature determined by Rand and Markin and on the experimental conditions for reduction. Two reduction techniques are considered: the flowing hydrogen system and the C-CO-CO2 system. At the usual temperatures for reduction, the partial pressure of water, the hydrogen flow, and the total weight of plutonia are the most important factors in the hydrogen system, while in the C.CO-CO2 system the important factors are the weight of the plutonia in each oxide pellet, the partial pressure of carbon monoxide, the proximity of the oxide and the carbon used for reduction, and the oxygen-to-metal ratio possible at the oxygen potential of the C-CO-CO2 equilibrium.
Electrophysiological effects of etoxadrol (CL-1848C): A new intravenous anaesthetic agent.

Abstract Etoxadrol (CL-1848C) and ketamine, although structurally dissimilar, both induce similar states of anaesthesia. In cats with chronically-implanted electrodes, Etoxadrol-induced anaesthesia is characterized by a progressive increase in CNS excitability with high voltage hypersynchrony and spikes occurring at intravenous doses of 5–10 mg/kg and convulsions at doses of 15–25 mg/kg. Complete recovery occurs within 24 hr. With anaesthetic doses of Etoxadrol, only minimal alterations in evoked cortical and subcortical potentials are observed. Comparison is made between the electrophysiological alterations induced by Etoxadrol and those induced by other anaesthetics. The limitations to the evaluation of evoked potentials in the determination of anaesthetic properties of a drug is discussed: i.e. some clinically-useful anaesthetics depress evoked cortical and subcortical potentials (ether, halothane, barbiturates) while others exert no change (Althesin, isoflurane, ketamine, Etoxadrol) or augmment (enflurane) the same potentials.
Integer-coefficient FIR filter sharpening for equiripple stopbands and maximally flat passbands

Linear-phase FIR filters with deep, equiripple stopbands are constructed using Chebyshev polynomials to sharpen short linear-phase subfilters. The Chebyshev recursion yields a natural implementation structure using only local interconnections between subfilter copies. Small-integer coefficients often suffice for the subfilters, because of their shallow stopbands, and power-of-two coefficients often suffice for the sharpening structure. Included are several passband-flattening techniques, most of which also use only small-integer coefficients.
Evaluation and optimization of mass transport of redox species in silicon microwire-array photoelectrodes

Physical integration of a Ag electrical contact internally into a metal/substrate/microstructured Si wire array/oxide/Ag/electrolyte photoelectrochemical solar cell has produced structures that display relatively low ohmic resistance losses, as well as highly efficient mass transport of redox species in the absence of forced convection. Even with front-side illumination, such wire-array based photoelectrochemical solar cells do not require a transparent conducting oxide top contact. In contact with a test electrolyte that contained 50 mM/5.0 mM of the cobaltocenium+/0 redox species in CH3CN–1.0 M LiClO4, when the counterelectrode was placed in the solution and separated from the photoelectrode, mass transport restrictions of redox species in the internal volume of the Si wire array photoelectrode produced low fill factors and limited the obtainable current densities to 17.6 mA cm-2 even under high illumination. In contrast, when the physically integrated internal Ag film served as the counter electrode, the redox couple species were regenerated inside the internal volume of the photoelectrode, especially in regions where depletion of the redox species due to mass transport limitations would have otherwise occurred. This behavior allowed the integrated assembly to operate as a two-terminal, stand-alone, photoelectrochemical solar cell. The current density vs. voltage behavior of the integrated photoelectrochemical solar cell produced short-circuit current densities in excess of 80 mA cm-2 at high light intensities, and resulted in relatively low losses due to concentration overpotentials at 1 Sun illumination. The integrated wire array-based device architecture also provides design guidance for tandem photoelectrochemical cells for solar-driven water splitting.
Perceived Social Support by Children with Characteristics of Attention-Deficit/Hyperactivity Disorder.

This comparative study concerned students’ perceptions of social support behaviors exhibited by significant adults and peers at school. A total of 29 teachers and 94 boys, in Grades 3 through 6, and their parents participated in the project from seven schools in three school districts in Minnesota, Nebraska, and Wisconsin. Approximately half of the boys (n = 48) displayed significant levels of behaviors characteristic of AttentionDeficit/Hyperactivity Disorder ({ADHD} characteristics group). The remaining boys ( n = 46) were randomly chosen from classrooms and did not display characteristics of ADHD (comparison group). Information on students’ academic performance, social skills, selfconcept, and problem behaviors was assessed via rating scales completed by the students and their respective parents and teachers. Brief questionnaires developed by the authors were used to also collect perceptions of social support from the teachers and parents. The data from these rating scales indicated that children with characteristics of ADHD, when compared with a control group, perceived lower frequencies of overall social support. Children with more severe ADHD-type behaviors perceived less overall social support and less support from classmates and close friends. Both the ADHD characteristics group and comparison group perceived the importance of social support similarly; social support was moderately and significantly correlated with self-concept and student-reported positive social skill behaviors; and students’ perceptions of social support were moderately related to parents’ and teachers’ perceptions of the frequency of social support they make available. These results are discussed and their implications for future research and practice are outlined.
Optical Fiber Measurements: Results Of Interlaboratory Evaluations

Results of industry-wide round robin comparisons administered by the National Bureau of Standards and the Electronic Industries Association are presented. Multimode fiber parameters include attenuation, bandwidth, core diameter, and numerical aperture. Single-mode fiber parameters include cut-off wavelength and mode-field diameter.
Extracavitary lipoma of the heart. Operative resection.

Abstract A rare benign primary tumor of the heart found in a 40-year-old woman is reported. Although extracardiac in nature, some of these tumors may involve a significant portion of the heart itself, and thus careful preoperative cardiac catheterization and angiographic study are indicated. While difficult to recognize preoperatively, extracavitary lipoma may be suspected in patients with unexplained cardiomegaly and otherwise essentially normal cardiac physical findings.
Diffusion through Nematic Liquid Crystals

THE significance of liquid crystalline phases in biological systems1 has been the subject of much discussion. The occurrence of mesoforms in membrane structures1 and the known response of lyotropic2, nematic3 and Cholesterin 4–6 meso-phases to magnetic fields have led to the speculation that a possible mechanism for the interaction of a weak magnetic field (∼ 1,000 Oe) with a biological system is through influence on the rates of mass or charge transport through a membrane7. We have undertaken measurements of the diffusion of small molecules and ions through liquid crystal films to investigate this possibility and report here preliminary values for the diffusion constant of tritium through two nematic liquid crystals and evidence for a magnetic field effect on this constant.
Evidence for Cu Ion Formation by Dissolution and Dealloying the Al2CuMg Intermetallic Compound in Rotating Ring‐Disk Collection Experiments

Rotating ring-disk collection experiments and stripping voltammetry have been used to detect Cu ions generated by dissolution of the Al{sub 2}CuMg intermetallic compound in aqueous chloride solutions. Cu ions are generated under open-circuit conditions (open-circuit potential {minus}0.930 V{sub SCE}), or by slight anodic or cathodic polarization ({+-}0.050 V from the open-circuit potential). In all cases, Cu ion generation occurs even though the electrode potential is hundreds of millivolts negative of the equilibrium potential, E{sub Cu}. Results show that Cu ion generation is strongly dependent on the degree of solution aeration, indicating a role for Cu oxidants in the liberation process. Copper chloride-complex formation and local surface curvature effects can shift the Cu equilibrium potential in the active direction, but neither phenomenon appears to play a primary role in oxidation of Cu from the intermetallic compound. Rather, the results of this study support the notion that Cu ion generation involves (1) dealloying of the intermetallic compound, (2) nonfaradaic liberation of mechanically and electrically isolated metallic Cu clusters by physical coarsening of the dealloyed particle, and (3) oxidation of the electrically isolated Cu clusters. This Cu ion generation mechanism is believed to be a significant factor contributing to the poor corrosion resistancemore » and poor conversion coating characteristics of Al{sub 2}CuMg-bearing alloys.« less
Differential expression of messenger RNAs for somatostatin receptor subtypes SSTR1, SSTR2 and SSTR3 in adult rat brain : analysis by RNA blotting and in situ hybridization histochemistry

The messenger RNAs encoding three somatostatin receptor subtypes, SSTR1, SSTR2 and SSTR3, were detected in rat by RNA blotting and in situ hybridization histochemistry to identify the sites of synthesis and expression of these somatostatin receptor subtypes. RNA blotting revealed that SSTR1 messenger RNA of 3.8 kilobases was highly expressed in cerebral cortex, hippocampus, midbrain and hypothalamus. In situ hybridization histochemistry revealed that SSTR1 messenger RNA was localized to discrete layers of the cerebral cortex, the piriform cortex and the dentate gyrus of the hippocampus. SSTR1 messenger RNA was expressed at low levels in the cerebellum and pituitary and was not detectable in striatum or other peripheral organs. At least two SSTR2 messenger RNAs were detected by RNA blotting of 2.4 and 2.8 kilobases which correspond to the size of the spliced and unspliced forms of this receptor messenger RNA. SSTR2 messenger RNA detected by in situ hybridization is diffusely expressed in cerebral cortex and amygdala but is discretely localized to dentate gyrus in the hippocampus, medial habenula and ventromedial and dorsomedial nuclei and arcuate nucleus of the hypothalamus. The levels of SSTR2 messenger RNA are very low in the cerebellum and were not observed in the striatum or peripheral tissues other than the pituitary or adrenal gland. A single SSTR3 messenger RNA of 4.0 kilobases was seen in hippocampus, cerebral cortex, midbrain, hypothalamus and pituitary. However, the tissue with the highest levels of SSTR3 messenger RNA is the cerebellum with messenger RNA localized to the granule cell layer. The expression of the three different somatostatin receptor messenger RNAs are distinct but overlapping. Such distinct expression may contribute to the selective biological roles of the receptor subtypes.