cssi/SciSciGPT-SciSciNet huggingface dataset:
Inactivated MGMT by O6-benzylguanine is associated with prolonged G2/M arrest in cancer cells treated with BCNU.

HCT116 and HCT15 cells that highly express O6-methylguanine-DNA-methyltransferase (MGMT) displayed a transient cell cycle G2/M arrest in response to exposure to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) alone; however, 70–80% of cells were arrested in G2/M after treatment with O6-benzylguanine (BG) and BCNU. Cells accumulated in G2/M showed elevated levels of an inactive form of cyclin B1/p-Cdc2 (Tyr15) complex that was not associated with activation of Chk1/p-Cdc25C and was independent of p53/p21 status. The most prominent feature of cell death was the appearance of enlarged and multinucleated cells that was related to the inhibition of mitotic entry. In contrast, BG-resistant cell lines, HCT116 BBR and HCT15 BBR cells that contain mutations K165E and K165N of MGMT, respectively, displayed a normal cell cycle progression with a slight and transient increase in G2/M arrest at 24 h after treatments with either BCNU alone or BG combined with BCNU. The differences in the ability to progress toward G2/M after treatment with BG and BCNU between cells expressing wild-type MGMT and mutated MGMT were confirmed in CHO cells transfected with human wild type and K165E mutant MGMT cDNA, respectively. Thus, our findings suggest that BG-inactivated MGMT may be linked to cell signaling events, forcing cells into a permanent G2/M arrest in response to the DNA damages induced by BCNU.
Personas: practice and theory

i Personasi is an interaction design technique with considerable potential for software product development. In three years of use, our colleagues and we have extended Alan Cooperis technique to make Personas a powerful complement to other usability methods. After describing and illustrating our approach, we outline the psychological theory that explains why Personas are more engaging than design based primarily on scenarios. As Cooper and others have observed, Personas can engage team members very effectively. They also provide a conduit for conveying a broad range of qualitative and quantitative data, and focus attention on aspects of design and use that other methods do not.
NEITHER CATEGORICAL NOR SET-THEORETIC FOUNDATIONS

First we review highlights of the ongoing debate about foundations of category theory, beginning with Feferman’s important article of 1977, then moving to our own paper of 2003, contrasting replies by McLarty and Awodey, and our own rejoinders to them. Then we offer a modest proposal for reformulating a theory of category of categories that would actually meet the objections of Feferman and Hellman and provide a genuine alternative to set theory as a foundation for mathematics. This proposal is more modest than that of our (2003) in omitting modal logic and in permitting a more “top-down” approach, where particular categories and functors need not be explicitly defined. Possible reasons for resisting the proposal are offered and countered. The upshot is to sustain a pluralism of foundations along lines actually foreseen by Feferman (1977), something that should be welcomed as a way of resolving this long-standing debate.
Characterization of a sodium-dependent taurine transporter in rabbit choroid plexus

Taurine, a beta-amino acid, plays an important role as a neuromodulator and is necessary for the normal development of the brain. Since de novo synthesis of taurine in the brain is minimal and in vivo studies suggest that taurine does not cross the blood-brain barrier, we examined whether the choroid plexus, the blood-cerebrospinal fluid barrier, plays a role in taurine transport in the central nervous system. The uptake of [3H]taurine into ATP-depleted choroid plexus from rabbit was substantially greater in the presence of an inwardly directed Na+ gradient, whereas in the absence of a Na+ gradient taurine accumulation was negligible. A transient inside-negative potential gradient enhanced the Na(+)-driven uptake of taurine into the tissue slices, suggesting that the transport process is electrogenic. Na(+)-driven taurine uptake was saturable with an estimated Vmax of 111 +/- 20.2 nmol/g per 15 min and a Km of 99.8 +/- 29.9 microM. The estimated coupling ratio of Na+ and taurine was 1.80 +/- 0.122. Na(+)-dependent taurine uptake was significantly inhibited by beta-amino acids, but not by alpha-amino acids, indicating that the transporter is selective for beta-amino acids. Na(+)-dependent taurine uptake showed some selectivity for anions: the accumulation was comparable in the presence of Cl-, Br- and thiocyanate whereas I-, SO4(2-) and gluconate did not stimulate the uptake significantly. Collectively, our results demonstrate that taurine is transported in the choroid plexus via a Na(+)-dependent, saturable and apparently beta-amino acid selective mechanism. This process may be functionally relevant to taurine homeostasis in the brain.
Influence of grafted glia cells and host mossy fibers on anomalously migrated host granule cells surviving in cortical transplants

Abstract Embryonic cerebral cortex was transplanted over the cerebellum of one- to two-day-old rats. In mature rats, clusters of granule cells that failed to migrate into the internal granule cell layer were now found within the graft tissue. Immunocytochemical staining of astrocytic glial cells in the cortical transplants revealed that glial processes were distributed in an unusual polarized orientation in those regions that contained host granule cells. Other areas of the graft exhibited glia cells with processes that projected radially from their cell body, thus resembling fibrous astrocytes. Fibrous astrocytes in transplants, however, were more heavily stained than similar glial cells in the intact cerebral cortex of the host, indicating a quantitative difference in the glia fibrillary acidic protein. Acetylcholinesterase-positive fibers were observed between the clusters of granule cells in the cortical grafts. Such fibers traversed the molecular layer and, since they could be traced from the white matter of the host cerebellum, they were presumed to be mossy fibers. It is concluded that migration of external granule cells in the cerebellum can be altered by placing embryonic cerebral cortex next to the developing cerebellum. Granule cells that have migrated into the grafted cerebral cortical tissue nevertheless receive afferent fibres.
A note on isotropic elastic response

For an important class of incompressible isotropic elastic solids, the response function for the extra stress is a (tensor-valued) function of scalar type. It is shown here that the stress response for compressible isotropic elastic solids cannot be of scalar type.
Polarographic reduction of maleic anhydride, maleate and fumerate in pyridine

Abstract Maleic and fumaric acids in pyridine show only the reduction behaviour of the pyridinium ion, which is produced when any Bronsted acid of aqueous pKa less than ca 9 is dissolved in pyridine. The diethyl esters each show two one-electron waves, which pattern is characteristic for the electrochemical reduction of double bonds in proton-poor solvents. Maleic anhydride, which is a dihydrofuran, shows initially a single wave at a potential considerably more positive than the reduction potential of diethyl maleate; with time, a second maleic anhydride wave appears and grows at the expense of the first wave. The anhydride slowly reacts with the trace of moisture in the solvent to form maleic acid, which behaves as already indicated.
Simulations and experiments on higher resonant modes of cubic high dielectric resonator metamaterial

The metamaterial structure composed of cubic high dielectric resonators periodically arrayed in a low dielectric substrate is analysed and a flat metamaterial lens is used to improve the gain of a rectangular patch antenna. A dielectric slab is also discussed and compared with the metamaterial lens. Experimental results show that the proposed metamaterial flat lens can improve the gain of a patch antenna remarkably at both the first and the third resonant mode.
Marketing online banking services: The voice of the customer

US banks have invested heavily in developing online capabilities, with the expectation of migrating customers to the new cheaper delivery system. Results in the USA thus far have been mixed at best; market penetration is low and customer usage is sporadic, focusing mainly on simple tasks. This paper reports on the first of two studies conducted to investigate the reasons for the mediocre performance. A qualitative consumer study revealed significant differences in attitudes and opinions between early users and those that banks hope will adopt next. Most importantly, future prospects could be characterised as indifferent about online banking; many were not convinced about its benefits and the value it provides. While the potential to expand the market for online banking services exists, banks need to re-examine their marketing approach.
Intra-industry structure and the response toward rivals

This paper is a study of the pricing behavior of airline monopolists toward potential entrant carriers from different strategic groups. The results suggest that formerly regulated carriers price lower when faced by potential entrants from the newly certified carrier group than they do when they face only potential entrants from their own group. These results are consistent with the heretofore-untested hypothesis from Caves and Porter (1977) and Porter (1979) that rivalry is greater across groups than within groups.
The Family Doctor: Psychodynamic Psychotherapy in Tightly Knit Communities

Although unusual, psychodynamic psychiatrists engage in the practice of treating multiple members, and constellations of members, of families with psychodynamic psychotherapy as well as other treatment modalities. Such clinicians are considered the "Family Psychiatrist." Psychological characteristics of such families who cannot be referred to other clinicians are articulated. The literature on psychotherapy in small rural communities is reviewed as having relevance to define the ethical issues that arise in such treatments. These issues include: maintaining therapeutic neutrality; creating functional, flexible, and appropriate boundaries; maintaining confidentiality; promoting patient autonomy and growth; as well as managing conflicts of interest. Relevant countertransference issues are examined.
Single cell contributions to network activity in the hippocampus

Abstract The information processing capabilities of neuronal populations are a function of the connectivity and single cell properties of the neurons that comprise the network. An important area of investigation is how information is encoded and processed by neurons in the network. There is a growing body of evidence demonstrating how the specific biophysical properties of individual neurons contribute to network processing as a whole. We illustrate through several examples in the hippocampal formation how cellular biophysics can directly effect the timing of neuronal spiking in the context of on-going network oscillations and how network patterns can influence the intrinsic properties of single cells. We discuss the consequences of the cooperation and competition between single cell and network properties.
Charge distribution in the nitride of MNOS memory devices

The steady state charge distribution for weakly occupied traps is a universal function of position over most of the nitride, with dielectric constant and Frenkel-Poole coefficient α being the only material parameters. The transient charge distribution for constant current pulses is approximated by truncating the steady state distribution and the resulting relation between charge content and its centroid is used to fit experimental data which provides α-values of a reasonable magnitude. A diffusive component of charge motion during application of alternating polarity voltage pulses is identified, and its diffusion coefficient is related to the Frenkel-Poole emission rate from traps.
Angular distribution of photoelectrons from the 5d-subshell of Hg

Abstract The angular distribution of photoelectrons from the Hg 5d-subshell has been calculated in the near-threshold region and is found to be in good agreement with recent experiments.
Effect of diet on dental development in four species of catarrhine primates.

In this study, dental development is described in two pairs of closely related catarrhine primate species that differ in their degree of folivory: 1) Hylobates lar and Symphalangus syndactylus, and 2) Papio hamadryas hamadryas and Semnopithecus entellus. Growth increments in histological thin sections are used to reconstruct the chronology of dental development to determine how dental development is accelerated in the more folivorous species of each pair. Although anterior tooth formation appears to be unrelated to diet, both S. syndactylus and S. entellus initiate the slowest-forming molar earlier than the related less-folivorous species, which supports the hypothesis that dental acceleration is related to food processing. S. syndactylus initiates M2 crown formation at an earlier age than H. lar, and S. entellus initiates and completes M3 at an earlier age than P. h. hamadryas. Similar stages of M3 eruption occur earlier in the more folivorous species; however, the sex of the individual may also play a role in creating such differences. Although the age at M3 emergence is close to that reported for the end of body mass growth in lar gibbons, hamadryas baboons, and Hanuman langurs, M3 emergence may not be coupled to body mass growth in siamangs. Am. J. Primatol. 61:29–40, 2003. © 2003 Wiley-Liss, Inc.
Quality of life and sexuality following radical prostatectomy in patients with prostate cancer who use or do not use erectile aids.

Abstract Objectives It is well established that prostate cancer patients undergoing radical prostatectomy may experience disruptive side effects, most notably urinary incontinence and erectile dysfunction. The purpose of this study is to compare relevant outcomes between patients awaiting radical prostatectomy for prostate cancer and patients who already underwent the surgery, taking into account type of prostatectomy and use of erectile aids. Methods We compared self-reports of global quality of life, sexuality, urinary continence, and physical capabilities in 86 nerve-sparing patients, 89 standard-prostatectomy patients, 74 prostatectomy patients who used erectile aids, and a comparison group of 45 patients awaiting radical prostatectomy. Results Regardless of type of surgery, use of erectile aid, or preoperative status, most patients reported good quality of life. The best outcomes in sexuality were reported by patients who used erectile aids, who appeared similar in sexuality to patients awaiting surgery. When differences were detected, standard prostatectomy patients who did not use erectile aids scored worse in most areas of sexuality than nerve-sparing patients who did not use erectile aids. There were no differences in frequency of urinary leakage among the three surgery subgroups. Conclusions Although most patients reported problems in sexual and urinary function, global quality of life does not appear to be compromised following radical prostatectomy. Findings suggest that postsurgical sexuality differs depending on type of prostatectomy and use of erectile aids, while urinary function is similar across surgery groups. We conclude that erectile aids should be offered routinely to patients who are ineligible for nerve-sparing surgery or experience erectile difficulties following the nerve-sparing procedure.
Electronegativity and a model hamiltonian for chemical applications

Abstract A study is made of the connection between a one-electron model hamiltonian of the Anderson—Hubbard type and the electronegativity, both for free atoms and for simple binary compounds. Non-linear terms in the valence electron occupation number must be included in the hamiltonian in addition to the usual linear tenn. It is found that interatomic interactions occurring in the compound increase the non-linearity substantially over that for the separated atomic constituents. This approach improves the physical understanding of the connection between the clectronegativities of the cation and the anion and (1) the Fermi energies (work functions) of solid compounds and (2) charge transfer in heteronuclear molecules. Charge transfer is specifically discussed for donor-acceptor organic solids and for strongly polar molecules with mutual cation-anion polarization effects included.
Apparent Hall-Petch effects in polycrystalline lamellar TiAl

Abstract The mechanisms responsible for the extremely high Hall-Petch slope of Ky ≈ 5MPa m½, for grain sizes d in the range 3000–200 μm, in fully lamellar (FL) and nearly lamellar (NL) TiAl microstructures are explored. It is shown that the constraints exerted by the neighbouring crystals, particularly those oriented in the hard mode, are the dominant factors controlling the yield stress. At large grain sizes (and small sample dimensions), these constraints are largely relaxed, because of free boundary conditions, thereby severely underestimating the true yield stress. Numerically computed flow stress curves illustrate that the sample gauge diameter D, for approximating bulk behaviour, for Hall-Petch measurements, scales with the hard-mode (g°2) against soft-mode (g°1) critical resolved shear stress anisotropy. Thus, while D/d ≈ 10 meets the bulk requirement for nearly isotropic, fully γ alloys, the minimum number of crystals required to approach bulk behaviour is 400 or more (i.e. D/d ≥ 20) for nominal p...
Nanowell-Trapped Charged Ligand-Bearing Nanoparticle Surfaces: A Novel Method of Enhancing Flow-Resistant Cell Adhesion

Assuring cell adhesion to an underlying biomaterial surface is vital in implant device design and tissue engineering, particularly under circumstances where cells are subjected to potential detachment from overriding fluid flow. Cell-substrate adhesion is a highly regulated process involving the interplay of mechanical properties, surface topographic features, electrostatic charge, and biochemical mechanisms. At the nanoscale level the physical properties of the underlying substrate are of particular importance in cell adhesion. Conventionally, natural, pro-adhesive, and often thrombogenic, protein biomaterials are frequently utilized to facilitate adhesion. In the present study nanofabrication techniques are utilized to enhance the biological functionality of a synthetic polymer surface, polymethymethacrylate, with respect to cell adhesion. Specifically we examine the effect on cell adhesion of combining: 1. optimized surface texturing, 2. electrostatic charge and 3. cell adhesive ligands, uniquely assembled on the substrata surface, as an ensemble of nanoparticles trapped in nanowells. Our results reveal that the ensemble strategy leads to enhanced, more than simply additive, endothelial cell adhesion under both static and flow conditions. This strategy may be of particular utility for enhancing flow-resistant endothelialization of blood-contacting surfaces of cardiovascular devices subjected to flow-mediated shear.
CORPORATE PERFORMANCE STANDARDS AND SHAREHOLDER VALUE

Strategic plans need to be evaluated in rational economic terms. Earnings per share and book ROI no longer do the job. What is needed, the author contends, is a new shareholder value approach.
INCREASED RECOVERY OF SURFACTANT PROTEIN A IN AIDS-RELATED PNEUMONIA

Respiratory infection with Pneumocystis carinii (PC) is the most frequent serious opportunistic infection in the clinical setting of acquired immunodeficiency syndrome (AIDS). The factors responsible for the predisposition of human immunodeficiency virus (HIV)-infected patients for PC infection are not fully understood. We postulated that changes in the alveolar lining material (ALM) could play a role in the pathogenesis of PC infection in AIDS. We have compared constituents of ALM in bronchoalveolar lavage fluid from normal, nonsmoking volunteers with that of HIV-infected patients with pneumonia. Using an ELISA, we found that surfactant protein A (SP-A) was markedly elevated in the pneumonia patients. Mean SP-A values for the normal nonsmoking individuals (n = 21) were 1.50 +/- 0.25 micrograms/ml (mean +/- SEM). SP-A levels in the HIV-infected patients (n = 22) were significantly elevated (p less than 0.01) with a mean of 5.23 +/- 0.54 micrograms/ml. This increase was greatest in the patients with more clinically severe pneumonia. The increase in SP-A did not appear to be pathogen-specific as it was also observed in cases of non-PC pneumonia. We also found that total protein levels were nearly five times higher in the HIV-infected pneumonia patients. These studies indicate that the protein component of the ALM is markedly different from normal in cases of HIV-associated PC and non-PC infection. Further investigation is needed to determine the mechanism of these alterations and their role, if any, in AIDS-related pneumonia.
Integrated high-quality factor silicon-on-sapphire resonators for mid-infrared applications

We demonstrate high-quality (Q) factor grating-coupled silicon-on-sapphire ring resonators, operating around 4.5 μm. Total Q-factors of 151,000 and intrinsic Q-factors of 278,000 are measured, enabling applications in nonlinear wavelength generation and other areas.
Interspecific differences in hematozoan infection in Sonoran desert Aimophila sparrows

Numerous studies have identified factors that control avian hematozoan infections, but the mechanisms that account for host differences in parasitemia remain largely speculative. To address this issue, we compared the prevalence of these parasites in stained blood smears from four conspecific Sonoran desert Aimophila sparrow species sampled during their breeding season: rufous-winged (Aimophila carpalis; RWSP), rufous-crowned (Aimophila ruficeps; RCSP), Cassin's (Aimophila cassinii, CASP), and Botteri's (Aimophila botterii; BOSP) sparrows. Blood smears contained Haemoproteus fringillae (RWSP), Trypanosoma everetti (RWSP, RCSP, BOSP), Trypanosoma avium (CASP), and microfilariae (all species). Most (92.5%) RWSP (n=40) were infected with Haemoproteus, but this parasite was not detected in RCSP (n=20) or BOSP (n=20) and was found only in one (2.5%) CASP (n =40). Trypanosoma spp. and microfilariae were detected in all species, but prevalence differed between these four sparrow species. Species differences in p...
The Neurobiology of Cocaine Addiction

Cocaine produces its psychoactive and addictive effects primarily by acting on the brain's limbic system, a set of interconnected regions that regulate pleasure and motivation. An initial, short-term effect -- a buildup of the neurochemical dopamine -- gives rise to euphoria and a desire to take the drug again. Researchers are seeking to understand how cocaine's many longer term effects produce addiction's persistent cravings and risk of relapse. In the author's laboratory, work has focused on buildup of the genetic transcription factor DeltaFosB. Levels of DeltaFosB in the limbic system correlate with addiction-like behaviors in mice and may precipitate very long-lasting changes to nerve cell structure. Further pursuit of this and similar leads are first steps toward a complete understanding of the transition from cocaine abuse to addiction -- and, ultimately, more effective treatments for those who are addicted.
Limits on achievable intensity reduction with an optical occulter: reply to comment

External occulters for NASA exoplanet missions have been proposed as the means to suppressing the Poisson spot intensity by at least 10 orders of magnitude. The leading proposed external occulter shapes adhere to the binary petaled occulters with sharp petal tips. In a recent paper, Wasylkiwskyj and Shiri [J. Opt. Soc. Am. A28, 1668 (2011)JOAOD60740-323210.1364/JOSAA.28.001668] (WS2011) investigated two forms of occulters: a binary petaled occulter and a circular partially transparent occulter. They showed that the achievable intensity reduction for a petal-style occulter is limited by the radii of curvature at the petal tips. For a partially transparent occulter they derived the optimum transparency function that minimizes the intensity on the optic axis within a prescribed wavelength range and provides the required intensity suppression. Since the publication of WS2011, a paper by Cash describes the analytical model of the occulter [Astrophys. J.738, 76 (2011)10.1088/0004-637X/738/1/76ASJOAB0004-637X] and recent commentary by Cash and Lo [J. Opt. Soc. Am. A29, 913 (2012)JOAOD60740-3232] (CL2011) compares the intensity reduction of petal shape functions and concludes prematurely against the petal shapes in WS2011. In this correspondence, we analyze the performance of a petal shaped occulter with petals tips of 0.1 mm width (following the prescription of CL2011) and show that its suppression performance is compatible with the calculations reported in WS2011 and measured intensity reduction reported in [Proc. SPIE6687, 66871B (2007)10.1117/12.742927PSISDG0277-786X] and [Proc. SPIE6693, 669305 (2007)10.1117/12.734480PSISDG0277-786X].
Anticonvulsant effects of restraint and pyridoxine on hydrazine seizures in the monkey.

Abstract This study compared convulsive and related preconvulsive responses to monomethylhydrazine (MMH) in three groups of chaired rhesus monkeys. One group served as a control and the other two as experimental groups to evaluate the influence on these measures of arm restraint and pyridoxine, respectively. Control animals displayed emesis, preictal responses, and generalized seizures within the first 75 min after MMH injection. Pyridoxine-treated animals showed emesis but no preictal or ictal behavior during this period, and arm-restrained animals showed no emesis, preictal, or ictal behavior. Control animals exhibited a criterion of three generalized seizures, after which chemotherapy was administered, within the first 100 min after MMH injection. Neither pyridoxine-treated nor arm-restraint animals showed any generalized seizures during a standard 240-min observation period, although both groups eventually displayed emesis and preictal responses. The protective effects of pyridoxine were interpreted within the context of established neurochemical influences of the hydrazines on synthesis of the inhibitory neurotransmitter, gamma-aminobutyric acid. The protective effect of restraint was related to similar observations in the literature and discussed in terms of central nervous system activation, inhibitory neurotransmitter dynamics, and correlated somatosensory electroencephalogram patterns indicative of an anticonvulsant “immobilization state”.
Dynamic fracture toughness of polypropylene reinforced with cellulose fiber

To better understand mechanisms of fracture under impact loading in cellulose-reinforced polypropylene, dynamic fracture analysis was performed based on linear elastic fracture mechanics. Dynamic critical energy release rates and dynamic critical stress intensity factors were deduced from instrumented Charpy impact test measurements. Dynamic fracture toughness increased with cellulose content. However, the assumption of linear elasticity began to break down for cellulose fiber contents exceeding 40% by weight. Scanning electron microscopy showed considerable fiber curl in the composites, especially at low fiber contents; at high fiber contents, composites developed a three-layer structure.
Choice reaction time and the nature of the choice response

Difference between choice and simple RT (reaction time) was much smaller on a step-tracking task than on ungraded tasks having similarly direct stimulus-response mapping. Explanation of PR (psychological refractoriness) by noncon-gruent response organizations was thus supported. On step tracking, choice RT was less than 10 msec longer than simple RT, implying that the processing steps either took little more total time or else had overlapping aspects.
Individual recognition by use of odours in golden hamsters: the nature of individual representations

Although much is known about individual recognition, little is known about the representations that individual animals have of other individuals. We examined the nature of this knowledge in golden hamsters, Mesocricetus auratus, using habituation–discrimination techniques. Male hamsters were first familiarized with two females; they were later habituated to one type of odour (vaginal secretions, flank gland, urine or ear scent) from one of these females and tested for cross-habituation (generalization) to another odour from the same female. Cross-habituation was shown across three of these odours (vaginal secretions, flank gland and ear scent). This effect did not occur if the males had not been familiarized with the female scent donors. These results show that males generalized between two scents from the same individual, presumably because the two odours had the same meaning. The results suggest that males formed integrated, multicomponent representations of females. Additional experiments showed that the cross-habituation effect requires interaction between individuals; mere exposure to the odours of an individual in its home cage is not sufficient. Cross-habituation between different odours did not occur when urine was used as one of the stimuli, even though urine was individually distinguishable. We suggest that the reason for this is that urine is too costly to be used for communication in this species because of selection for conservation of water.
MAGNETIC RESONANCE STUDIES OF MEMBRANE AND MODEL MEMBRANE SYSTEMS. V. COMPARISONS OF AQUEOUS DISPERSIONS OF PURE AND MIXED PHOSPHOLIPIDS

Phospholipid regions in cellular membranes are involved in a variety of functions, including the maintenance of permeability barriers and associations with some proteins to form functional entities. The evidence available from several physical techniques suggests that in nearly all of the membranes studied there are regions in which phospholipids are arranged in bilayers which exhibit varying degrees of mobility (or fluidity). The bilayer arrangement of phospholipids in cellular membranes is not accidental; it is a manifestation of their amphiphilic nature, and it occurs when they are isolated and dispersed into water. Since the phospholipids spontaneously form bilayer structures in water that are similar to those found in cellular membranes, and since phospholipids in lipid-water model systems are more easily studied than those in complicated membranes, it has been assumed that bilayers composed of aqueous phospholipid dispersions provide a reasonable model and convenient point of departure for studying the phospholipids in membranes. Partial solutions to questions concerning the nature of phospholipid bilayers are beginning to emerge from the results of several physical techniques. Of these techniques, NMR has been of great use in elucidating the motion of the fluid fatty acids of lecithin. In particular, T/sub 1/ measurements have provided informationmore » concerning fast processes, and T/sub 2/ measurements have provided information about relatively slower processes. This paper discussed briefly some relevant topics in relaxation theory, review work on both sonicated and unsonicated lecithins and the dynamic model that is proposed to explain the relaxation data, report some effects of altered fatty acid composition on the NMR parameters, report results concerning the interactions of cations with two phospholipids; phosphatidylcholine which is zwitterionic and phosphatidylglycerol (PG) which is anionic, and, finally, the behavior of aqueous dispersions of PC--PG mixtures.« less
Creating biocompatible oil-water interfaces without synthesis: direct interactions between primary amines and carboxylated perfluorocarbon surfactants.

Currently, one of the most prominent methods used to impart biocompatibility to aqueous-in-oil droplets is to synthesize a triblock copolymer surfactant composed of perfluoropolyether and polyether blocks. The resulting surfactants (EA surfactant, KryJeffa, etc.) allow generation of highly biocompatible droplet surfaces while maintaining the heat stability of the starting material. However, production of these surfactants requires expertise in synthetic organic chemistry, creating a barrier to widespread adoption in the field. Herein, we describe a simple alternative to synthetic modification of surfactants to impart biocompatibility. We have observed that aqueous-in-oil droplet surfaces can be made biocompatible and heat stable by merely exploiting binding interactions between polyetherdiamine additives in the aqueous phase and carboxylated perfluorocarbon surfactants in the oil phase. Droplets formed under these conditions are shown to possess biocompatible surfaces capable of supporting picoliter-scale...
Development of a bond-valence molecular-dynamics model for complex oxides

A simple ten-parameter interatomic potential model is described that is capable of accurately reproducing the static and dynamical properties of complex oxides. The accuracy of this model stems from the crystal-chemical bond-valence theory of ionic and covalent bonding. The development of a specific variant of this model for ferroelectric $\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ (PT) is discussed in detail, and comparison of the model is made with density functional theory computations and with experimental data. Bond-valence molecular dynamics (BVMD) simulations for PT show a ferroelectric transition at $575\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The BVMD model correctly reproduces the mixed order-disorder and displacive phase transition character, the magnitudes of cation displacements in the ferroelectric and paraelectric phases, and the energy of 180\ifmmode^\circ\else\textdegree\fi{} domain walls. The success of this simple and physically motivated model makes the simulation of extended defects tractable in PT and other complex oxides.
New upper limits on the tau-neutrino mass from primordial helium considerations.

In this paper we reconsider recently derived bounds on MeV tau neutrinos, taking into account previously unaccounted for effects. We find that, assuming that the neutrino lifetime is longer than \ensuremath{\sim}100 sec, the constraint ${\mathit{N}}_{\mathrm{eff}}$3.6 rules out ${\ensuremath{\nu}}_{\mathrm{\ensuremath{\tau}}}$ masses in the range 0.5${\mathit{m}}_{\ensuremath{\nu}\mathrm{\ensuremath{\tau}}}$35 MeV for Majorana and 0.3${\mathit{m}}_{\ensuremath{\nu}\mathrm{\ensuremath{\tau}}}$35 MeV for Dirac neutrinos. Given that the present laboratory upper bound is 31 MeV, our results imply an upper bound of 0.5 MeV for Majorana neutrinos and of 0.3 MeV for Dirac neutrinos.
On possible psychophysical maps: II. Projective transformations

Projective transformations can be used to map multidimensional physical spaces into multidimensional perceptual spaces; they can be related to the quadratic transformations discussed in an earlier paper.
Duloxetine Does Not Relieve Painful Physical Symptoms in Depression: A Meta-Analysis

Background: Duloxetine inhibits both serotonin and norepinephrine reuptake and is marketed as a treatment for both the core emotional symptoms and painful physical complaints that of
Positional changes in mesio-angular impacted mandibular third molars during a year

Age of patient and amount of change in the inclination of the mandibular third molar are significantly related; the data from this study show that positional changes can occur in the third molar until the patient is at least 20 years of age. In 296 young men, mandibular third molars in mesio-angular impacted positions attained a more upright position during a yearlong observation period.
Why Should Secondary Schools Be Concerned with Reading

Improvement of reading skills is a high priority in many schools today. If every student is to reach his potential, every teacher must play a part. Drake tells how below.
Behavioral Toxicology of Volatile Organic Solvents I. Methods: Acute Effects:

Behavioral toxicity of toluene has been measured in mice. Because of its small size the mouse can be confined in a 251. hermetically sealed chamber for several hours. Toluene was introduced through a port and vaporized by a hotplate. Samples of chamber air for analysis were taken through another port. A smaller mesh cage held the mouse within the larger chamber. Schedule-controlled responding was developed by arranging that a response, breaking a beam of light, was followed by milk under an FI 60-sec schedule. Responding was much more rapid in the presence of stimuli correlated with the FI schedule than when the schedule was not operating. Standard sessions consisted of alternating series of 8 consecutive FI 60-sec and interseries 30-min time-outs.Following introduction of liquid toluene, the concentration in the chamber reached its asymptote within 60 sec. Toluene disappeared from the atmosphere of the unopened empty chamber at the rate of 0.2%/hr. When the mouse cage was in the chamber the disappearance...
Do young children use the discounting principle

Abstract According to the discounting principle, the perceived role of a given cause in leading to a given effect is diminished when other possible causes for that event are also detected. Use of this principle is believed to underlie the overjustification effect: when people are pressured to engage in an enjoyable activity, their intrinsic motivation decreases. However, overjustification effects have been documented in young children, even though past research indicates that children less than 7–8 years of age do not use or understand the discounting principle. This research reexamines this paradox. Past discounting studies have ignored evidence that young children often prefer entity to person causes of behavior. The two experiments reported here demonstrate that when tested appropriately, even young children use the discounting principle and can apply it to their understanding of an overjustification-type situation. Results are discussed in terms of the attributional mediation of behavior and the importance of taking into account the nature of subjects' social knowledge when examining their use of attributional principles.
Climbing in 190 Dimensions

Those who have looked at the night sky—not the dim remnant visible in cities, but the bright complexity seen in high, dark places—can appreciate the task assumed by Wochner et al. ( 1 ). On page 209, they describe the construction of an RNA enzyme (a template-dependent primed RNA polymerase) that emulates an ancient molecule that would have been crucial in the “RNA world,” believed to have predated DNA- and protein-based life. To find this enzyme, they searched vast molecular populations, holding potentially many, many more RNAs than the visible universe has stars.
Perceptions of intercultural communication competence and international student adaptation to an American campus

International students are enrolling in American colleges and universities in increasing numbers, yet we know little of their communicative experiences on United States campuses. This study examined perceptions of intercultural communication competence and adaptation in international students studying on an American campus. Participants in the study were 101 international students enrolled in a medium‐sized university in the Midwest. Results suggest that while the affective and behavioral dimensions of intercultural communication competence are related to students' satisfaction with their communication skills, talking with American students was the single most important factor in perceptions of communication competency and adjusting to American life. Practical implications of these results for communication instruction are discussed.
An automatic energy-calibration method for segmented germanium detectors

An automatic gain-matching method has been developed for the energy calibrations of the 32 segments of a large-volume germanium detector. The method calibrates the small-volume segments relative to the central contact, which collects the charge from the total germanium crystal volume and can be efficiently calibrated with known sources. The method presented here can employ photons of arbitrary energy. With the use of in-beam γ-rays for segment calibrations it presents an efficient way to perform continuous energy calibrations in experiments.
Comment on "Abrupt and gradual extinction among Late Permian land vertebrates in the Karoo basin, South Africa".

In a groundbreaking paper, Ward et al . ([ 1 ][1]) provided both the stratigraphic context and a quantitative description of the terrestrial vertebrate fossil record across the Permian-Triassic (P-T) boundary from the Karoo basin in South Africa. They drew three primary conclusions: (i) that there
Acculturation of Mexican-American mothers influences child feeding strategies.

Abstract Objective The purpose of this study was to examine the influence of maternal acculturation level on child feeding strategies and anthropometry in preschoolers from low-income Mexican-American families. Design/Subjects Data are from a cross-sectional survey of 238 low-income Mexican-American families with preschool children living in California during 1998. Interviewers collected data from the mothers on child-feeding practices and weighed and measured the children in their homes. Statistical Analyses Spearman's correlation coefficients, analysis of variance, and χ 2 were used to examine the relationship of maternal acculturation level with feeding strategies and anthropometric measurements. Results Compared with more acculturated mothers, less acculturated mothers tend to offer alternative foods more often when their children refuse to eat. More acculturated women are less likely to view bribes, threats, and punishments as effective strategies and are more likely to give vitamins than less acculturated mothers. Maternal acculturation is not associated with differences in weight-for height z-scores, height-for-age, or body mass index of the children. Triceps skinfold thickness are larger in children of more acculturated mothers than in children of less acculturated women. Applications/Conclusions Dietitians should consider differences in child feeding practices due to acculturation among Mexican-Americans. Successful strategies to encourage consumption of nutritious traditional foods and to transition from child-led snacking to more structured meals should be part of nutrition education programs. J Am Diet Assoc, 2001;101: 542–547 .
Imaging implicit perception: promise and pitfalls.

The study of implicit perception — perception in the absence of awareness — has a long history. Decades of behavioural work have identified crucial theoretical and methodological issues that must be considered when evaluating claims of implicit perception. Neuroimaging methods provide an important new avenue for illuminating our understanding of perception both with and without awareness, but most imaging experiments have not met the rigorous conditions that the behavioural work has shown are necessary for inferring implicit perception. Here, we review the literature of both behavioural and neuroimaging studies, and note the pitfalls of studying implicit perception as well as the promise that neuroimaging studies have for providing insights about implicit perception when combined with appropriately rigorous behavioural measures of awareness. There are many controversies involved in the study of implicit perception. Some proponents argue that it has a pervasive influence on thoughts and actions, whereas sceptics argue against its existence (BOX 1). Decades of behavioural research have led to a refined understanding of the theore- tical and empirical pitfalls of studying implicit perception 1,2 ,b ut the debate over its existence and nature persists 3-14 .N euro- imaging methods can provide insights that would be unattainable using strictly behav- ioural measures, but their success requires full appreciation of the theoretical and empirical challenges involved in showing implicit perception. This article discusses the central theoretical issues, which have been derived from decades of behavioural work ,i dentifies common shortcomings in the evidence for implicit perception, evalu- ates recent neuroimaging data in light of the behavioural evidence and methodologi- cal issues, and, finally, investigates how neuroimaging might be used to enhance our understanding of perception without awareness. Behavioural approaches Recent sceptical critiques of the evidence for implicit perception 15 have led to increased rigor and methodological creativity in attempts to document its existence. Although controversies remain, most proponents and sceptics agree on two central ideas: that the evidence for implicit perception cannot rely solely on participants to accurately report their state of awareness on each trial, and that qualitative differences in performance can support claims of implicit perception even if they are not definitive on their own. Reliance on subjective reports. Most empirical approaches to studying implicit perception take the same form: they show the absence of conscious perception of a stimulus but show the influence of the stimulus using other mea- sures, an approach known as the dissociation paradigm (BOX 2) .T o measure awareness, most studies of implicit perception, particularly in the neuroimaging and neuropsychology liter- atures, rely on the observers to report their state of awareness. The use of such subjective reports of awareness is intuitive and appeal- ing; it trusts the observers to have optimal access to the level of their own awareness.
Gene therapy and uterine leiomyoma: a review

Leiomyomas (fibroids) are common estrogen-dependent uterine tumours that cause significant morbidity for women and a substantial economic impact on health delivery systems. Currently, there is no effective medical treatment option for this condition-hysterectomy is the mainstay of management. This is not an attractive choice for many women, especially patients desiring to preserve their fertility potential. Gene therapy is becoming a clinical reality, with more than 600 clinical trials worldwide. Researchers have recently attempted to develop a gene-therapy-based approach for the ablation of uterine fibroids. The localized nature of this condition and its accessibility using different imaging or endoscopic techniques make it an attractive target for direct delivery of gene-based vectors. Recent work from our laboratory suggests the potential use of a dominant-negative form of estrogen receptor (ER) to inactivate estrogen signalling in leiomyoma cells and induce apoptosis. Our in vivo data in a mouse model demonstrate the ability of an adenovirus-expressing dominant-negative ER to arrest leiomyoma growth. We and others also have described the utility of the herpes simplex virus-thymidine kinase (HSV-TK) plus ganciclovir (GCV) suicide gene-therapy system to effectively eradicate leiomyoma cells by utilizing the bystandard effect phenomena and the high expression of gap-junction protein in these tumours. Further work on rat models will pave the way for future leiomyoma gene-therapy clinical trials and allow the realization of gene therapy as a viable non-surgical option for this common problem in women's health.