cssi/SciSciGPT-SciSciNet huggingface dataset:
Controlled-rate freezing to regulate the structure of collagen-glycosaminoglycan scaffolds in engineered skin substitutes.

Controlled rate freezing (CRF) of biopolymer scaffolds may increase reproducibility of microstructure compared to analog processes. Freezing of collagen-glycosaminoglycan (CG) scaffolds by CRF with liquid nitrogen at chamber cooling rates of −80°C, −40°C, −20°C, or −10°C/min, was compared to submersion in 95% ethanol at −55°C. Cooling rates of −80°C/min or −40°C/min generated scaffolds with pore areas and pore fractions that were comparable to scaffolds frozen in ethanol. Test and control scaffolds were populated with human dermal fibroblasts and keratinocytes to generate engineered skin substitutes (ESS), and evaluated for surface hydration and mitochondrial metabolism. ESS with scaffolds frozen by CRF at −80°C/min or −40°C/min were comparable to, or better than ESS with control scaffolds (p<0.05). These results demonstrate that fabrication of CG scaffolds by CRF offers advantages of digital programming, as well as greater reproducibility, safety and simplicity than submersion in chilled ethanol without compromise of biological properties required for biomedical applications.
The adaptation and introduction of Hewlett Packard's Teamwork into a microprocessor-based digital systems laboratory

Hewlett Packard Teamwork is a computer-aided software engineering package which contains many features which make it adaptable to a mixed hardware/software design approach such as that used in microprocessor-based design. The modifications needed for such a mixed hardware-software design approach and its subsequent introduction into the microprocessor-based digital systems design laboratory at the University of California, Santa Barbara are discussed. The procedure for introducing Teamwork was divided into two distinct phases. The first phase consisted of establishing a set of rules which would serve as guidelines for the first group of students to use the tool. The result of this initial work was a users manual, to be used in the second phase, which contained references, the user guidelines, and design examples. The second phase of the project involved introducing the tool to a graduate-level microprocessor design class, ECE 252C. The authors cover both phases in chronological order, highlighting problems and the solutions which were adopted. >
Demonstration of tissue receptors for viruses.

SummaryBy using a principle analogous to that of mixed agglutination, virus-treated RBC may be caused to adhere to tissue sections in a slide chamber test. The adherence depends on the presence of virus receptor sites on both tissue and RBC; thus the occurrence of hemadsorption serves as a useful indicator for the presence of receptor sites in the tissue tested. Treatment of tissue or RBC with RDE prevents the occurrence of hemadsorption, as does treatment of the tissue with periodate. In the chick embryo, infection with NDV seemed to eliminate tissue receptors for this virus. The technique should prove applicable to studies of species susceptibility to viral infection and to studies of organotropism of viruses.
Dense energetic compounds of C, H, N, and O atoms. III. 5‐[4‐nitro‐(1,2,5)oxadiazolyl]‐5H‐[1,2,3]triazolo[4,5‐c][1,2,5]oxadiazole

Abstract : Diazidoazofurazan 8 was obtained from the bis-diazonium salt of diaminoazofurazan 7 by treatment with sodium azide and underwent thermolysis to 5-(4-azido-(1,2,5)oxadiazolyl)-5H-(1,2,3)triazolo(4,5,-c)(1,2,5)oxadiazole 5. The corresponding amine 13 was obtained from the azide 5 by reduction with stannous chloride and was oxidized by ammonium persulfate to 5-(4 nitro-(1,2,5) oxadiazolyl)-5H-(1,2,3)triazolo(4,5-c)(1,2,5)oxadiazole 1. The azide 5 was converted to a phosphinimine 9 in a reaction with triphenylphosphine
New business incubators

Abstract The United States has incomparable advantages over all other nations, not only to recapture and maintain technical-industrial leadership in most areas of commerce, but to provide international leadership to expand the global economy and raise the quality of life of all nations. 1. • The U.S. currently spends about $15 billion each year in basic research to expand the fundamental pool of knowledge. This is many times greater than any other nation, and represents an enduring and powerful advantage. It also provides an historically unprecedented array of application opportunities for all nations to create innovative niche businesses. 2. • The U.S. has the greatest breadth and depth of technical-industrial capability in the world to translate new discoveries into useful products, processes and services. 3. • The U.S. has a remarkable entrepreneurial culture which provides permission to fail and try again until success is achieved without permanent personal or public penalty. 4. • The U.S. has the largest pool of 4.5 million trained scientists and engineers in the world. 5. • The U.S. has the most flexible capital development capability in the world's largest market with a common language. U.S. industrial competitiveness requires that these unique capabilities be maximized through continued removal of barriers, provision of incentives, and continual catalysis of cooperative efforts through diverse centers of innovation. The professionally managed incubation center concept has emerged as a most successful model to this end.
Excitation of rainfall over the Tropical Western Pacific

AbstractThe authors have examined 4 years of satellite-derived SST and rainfall data in anticipation of a relationship between SST structure and the excitation of convective rainfall. The results exhibit a strong excitation signal consistent with the presence of mesoscale SST gradients in about 75% of approximately 10 000 rainfall onset events. Rainfall onset events occur at locations with enhanced horizontal convergence, as inferred by the Laplacian of SST on scales of order 100 km. The daily SST field exhibits multiscale patchiness, spanning a 2+°C range. The signal is disproportionately large at SSTs that are 0.25°C above the mean, near 29.5°C; disproportionately weak for SST ≤ 28.8°C; and proportionately neutral for SST ≥ 30.3°C. The calculations suggest that a characteristic strength of this lower-boundary forcing (~3 × 10−5 s−1) is approximately one order of magnitude stronger than the mean regional background forcing (~3 × 10−6 s−1). The periphery of warm oceanic patches exhibits both convergent an...
Chemiluminescence of β-lactam antibiotics following oxidation by potassium Superoxide

Abstract The complexes formed by potassium Superoxide (KO 2 ) with 18-crown-6-ether in acetonitrile are stable and extremely strong oxidizers. Eleven different β-lactam antibiotics were tested for Chemiluminescence (CL) by using such an oxidizer and seven of them gave measurable signals. A linear relationship was obtained between the chemiluminescent peak height and the concentration of penicillin G and dicloxacillin.
Comparison of 3 chelating agents in treatment of experimental manganese poisoning.

SummaryThree chelating agents of the polyamino polycarboxylic acid type, ethylene-diaminetetraacetic acid, diethylenetriamine-pentaacetic acid, and ethylene bis(α-imino-o-hydroxyphenylacetic acid) have been compared in treatment of acute experimental manganese poisoning. EBAA had no therapeutic value, whereas both EDTA and DTPA provided significant protection to rats given lethal amounts of manganese gluconate. It is shown that DTPA is somewhat more effective than EDTA.
Patient dissatisfaction and attempted suicide.

This paper deals with the presence of suicidal behavior in a mental health clinic and psychiatric emergency room, and its relationships to what has been described in the literature as the “dependent-dissatisfied” personality. Procedures included a suicidal potential scale, projective figure drawings, and a brief interview about past and present suicidal behavior. The scale used significantly differentiated between high and low potentially suicidal groups. The high suicidal group showed a significantly greater dissatisfaction with treatment both past and present. The implications for both evaluation and therapy of suicidal patients are discussed.
DNA Polymerase δ Is Highly Processive with Proliferating Cell Nuclear Antigen and Undergoes Collision Release upon Completing DNA

In most cells, 100-1000 Okazaki fragments are produced for each replicative DNA polymerase present in the cell. For fast-growing cells, this necessitates rapid recycling of DNA polymerase on the lagging strand. Bacteria produce long Okazaki fragments (1-2 kb) and utilize a highly processive DNA polymerase III (pol III), which is held to DNA by a circular sliding clamp. In contrast, Okazaki fragments in eukaryotes are quite short, 100-250 bp, and thus the eukaryotic lagging strand polymerase does not require a high degree of processivity. The lagging strand polymerase in eukaryotes, polymerase δ (pol δ), functions with the proliferating cell nuclear antigen (PCNA) sliding clamp. In this report, Saccharomyces cerevisiae pol δ is examined on model substrates to gain insight into the mechanism of lagging strand replication in eukaryotes. Surprisingly, we find pol δ is highly processive with PCNA, over at least 5 kb, on Replication Protein A (RPA)-coated primed single strand DNA. The high processivity of pol δ observed in this report contrasts with its role in synthesis of short lagging strand fragments, which require it to rapidly dissociate from DNA at the end of each Okazaki fragment. We find that this dilemma is solved by a “collision release” process in which pol δ ejects from PCNA upon extending a DNA template to completion and running into the downstream duplex. The released pol δ transfers to a new primed site, provided the new site contains a PCNA clamp. Additional results indicate that the collision release mechanism is intrinsic to the pol3/pol31 subunits of the pol δ heterotrimer.
Ethnic and gender differences in attitudes toward driving

A convenience sample of 424 students from the University of Texas at El Paso and Wright State University were surveyed about attitudes and behaviors regarding operating a motor vehicle. The object of this study was to examine the effects of gender and ethnicity on attitudes towards driving. Gender had more effects on driving attitudes than ethnicity. However, Hispanic students reported needing significantly more drinks to get drunk than non-Hispanics, regardless of gender despite weighing significantly less. These differences in behaviors may help account for the over-representation of the Hispanic ethnic groups in driving outcomes such as collisions and deaths.
The Bermuda Triangle of cocaine-induced neuroadaptations

Activation of medium spiny neurons (MSNs) of the nucleus accumbens is critical for goal-directed behaviors including cocaine seeking. Studies in cocaine-experienced rodents have revealed three major categories of neuroadaptations that influence the ability of glutamate inputs to activate MSNs: changes in synaptic AMPA receptor levels, changes in extracellular non-synaptic glutamate levels and changes in MSN intrinsic membrane excitability. Most studies have focused on one of these adaptations. This review will consider the possibility that they are causally related and speculate about how time-dependent changes in their interactions may regulate MSN output during early and late withdrawal from repeated cocaine exposure.
Simultaneous DNA binding, bending, and base flipping: Evidence for a novel M.EcoRI methyltransferase-DNA complex

We measured the kinetics of DNA bending by M.EcoRI using DNA labeled at both 5′-ends and observed changes in fluorescence resonance energy transfer. Although known to bend its cognate DNA site, energy transfer is decreased upon enzyme binding. This unanticipated effect is shown to be robust because we observe the identical decrease with different dye pairs, when the dye pairs are placed on the respective 3′-ends, the effect is cofactor- and protein-dependent, and the effect is observed with duplexes ranging from 14 through 17 base pairs. The same labeled DNA shows the anticipated increased energy transfer with EcoRV endonuclease, which also bends this sequence, and no change in energy transfer with EcoRI endonuclease, which leaves this sequence unbent. We interpret these results as evidence for an increased end-to-end distance resulting from M.EcoRI binding, mediated by a mechanism novel for DNA methyltransferases, combining DNA bending and an overall expansion of the DNA duplex. The M.EcoRI protein sequence is poorly accommodated into well defined classes of DNA methyltransferases, both at the level of individual motifs and overall alignment. Interestingly, M.EcoRI has an intercalation motif observed in the FPG DNA glycosylase family of repair enzymes. Enzyme-dependent changes in anisotropy and fluorescence resonance energy transfer have similar rate constants, which are similar to the previously determined rate constant for base flipping; thus, the three processes are nearly coincidental. Similar fluorescence resonance energy transfer experiments following AdoMet-dependent catalysis show that the unbending transition determines the steady state product release kinetics.
Modulation of adhesion molecules on human large granular lymphocytes by interleukin-2 in vivo and in vitro.

Abstract The modulation of adhesion molecules on human large granular lymphocytes (LGL) by in-terleukin (IL)-2 was investigated both in vivo and in vitro . Intercellular adhesion molecule-1 (ICAM-1; CD54) expression increased on LGL of cancer patients receiving IL-2 adoptive immunotherapy. ICAM-1 expression on LGL isolated by Percoll gradient centrifugation, LGL purified, and expanded by adherence to plastic surfaces and LGL identified by Leu 19 (CD56) monoclonal antibody were increased significantly in response to IL-2 in vitro . Exposure of LGL to IL-1, interferon (IFN)-γ, and tumor necrosis factor (TNF) in vitro did not induce ICAM-1. The expression of LFA-1 (CD11a/CD18), a receptor for ICAM-1, and other leukocyte adhesion molecules, including Mac-1 (CD11b/CD18) and p150,95 (CD11c/CD18), was only maintained by IL-2. IL-2 induction of ICAM-1 and the maintenance of CD18 complex expression on small lymphocytes separated by Percoll gradients were similar to that on LGL. We conclude that IL-2 enhances the expression of ICAM-1 on multiple human lymphocyte populations including LGL effectors. Expression of the CD18 complex on LGL does not appear to be highly regulated by IL-2. These findings may have implications relevant to the role of these adhesion molecules in the activities of LGL modulated by IL-2.
Vacuum tunnelling thermopower: Normal metal electrodes

Abstract Theoretical results are presented for the vacuum tunnelling “thermopower” S  limit ΔT→O V (Δ T ) Δ T where V(ΔT) is the voltage required to null the thermal tunneling current generated by maintaining a temperature difference ΔT between the electrodes of the tunnel junction. To a good approximation the tunnelling thermopower depends on temperature T and vacuum gap d over a large range of these parameters only in the combination Td. This could, at least in principle, provide the basis of a direct method for measuring absolute vacuum gaps in scanning tunnelling microscopy.
Dissociative ionization of hot C3H5 radicals

The combination of ultraviolet (uv) photodissociation, vacuum-ultraviolet (vuv) photoionization, and velocity-map ion imaging is used to explore the dissociative ionization of allyl and 2-propenyl C3H5 radicals that have significant amounts of internal energy. The effect of the internal energy of the radicals on the fragmentation dynamics of the parent photoion is first discussed for the general case, and then for the specific C3H5 radicals. The results are relevant to an increasing number of studies in which single-photon vuv photoionization is used as a ‘soft’ ionization method for radicals produced in photodissociation and reactive scattering experiments, as well as in reactive environments such as flames and plasmas. †The submitted manuscript has been created by UChicago Argonne LLC, Operator of Argonne National Laboratory, (‘Argonne’). Argonne a US Department of Energy Office of Science Laboratory, is operated, under Contract No. DE-AC02-06CH11357 with the U.S. Department of Energy. The U.S. Governme...
Absorption Coefficient of HCl in the Region 1400 to 2200 Å

The results of absorption coefficient measurements of HCl in the region 1400 to 2200 A are reported and compared with those previously published. It is concluded that the present results represent the best compromise of all measurements and should be used for any calculations on the photodissociation rate of HCl in planetary atmospheres.
Mechanics of oriented electrospun nanofibrous scaffolds for annulus fibrosus tissue engineering

Engineering a functional replacement for the annulus fibrosus (AF) of the intervertebral disc is contingent upon recapitulation of AF structure, composition, and mechanical properties. In this study, we propose a new paradigm for AF tissue engineering that focuses on the reconstitution of anatomic fiber architecture and uses constitutive modeling to evaluate construct function. A modified electrospinning technique was utilized to generate aligned nanofibrous polymer scaffolds for engineering the basic functional unit of the AF, a single lamella. Scaffolds were tested in uniaxial tension at multiple fiber orientations, demonstrating a nonlinear dependence of modulus on fiber angle that mimicked the nonlinearity and anisotropy of native AF. A homogenization model previously applied to native AF successfully described scaffold mechanical response, and parametric studies demonstrated that nonfibrillar matrix, along with fiber connectivity, are key contributors to tensile mechanics for engineered AF. We demonstrated that AF cells orient themselves along the aligned scaffolds and deposit matrix that contributes to construct mechanics under loading conditions relevant to the in vivo environment. The homogenization model was applied to cell-seeded constructs and provided quantitative measures for the evolution of matrix and interfibrillar interactions. Finally, the model demonstrated that at fiber angles of the AF (28 degrees -44 degrees ), engineered material behaved much like native tissue, suggesting that engineered constructs replicate the physiologic behavior of the single AF lamella. Constitutive modeling provides a powerful tool for analysis of engineered AF neo-tissue and native AF tissue alike, highlighting key mechanical design criteria for functional AF tissue engineering.
User purposes and information-seeking behaviors in web-based media: a user-centered approach to information design on websites

In the effort to specify and evaluate the designing of web-based media to improve users' satisfaction, design principles are established for general use.These principles might be developed holistically, or they can be analyzed and formulated from extensive user research. Since information on websites is traditionally structured and presented based on the websites' goals and contents, it may or may not match with users' purposes and their search behaviors.This leads to users' struggle and frustration. As a result, this paper presents a relatively new area of user research in web-based media, offering a user-centered perspective with the consideration of users' purposes, users' modes of searching and their search behaviors. The information on web-based media should not be designed only to serve websites' goals and contents, but should also match with purposes and search patterns of the intended audience in order to improve their satisfaction and help accomplish their goals.
Phonons and conduction in molecular quantum dots: Density functional calculations of Franck-Condon emission rates for bifullerenes in external fields

We report the calculation of various phonon overlaps and their corresponding phonon emission probabilities for the problem of an electron tunneling onto and off of the fullerene-dimer molecular quantum dots ${\mathrm{C}}_{72}$ and ${\mathrm{C}}_{140}$, both with and without the influence of an external field. We show that the stretch mode of the two balls of the dumbbell couples most strongly to the electronic transition and, in turn, that a field in the direction of the bond between the two fullerene balls is most effective at further increasing the phonon emission into the stretch mode. As the field is increased, phonon emission increases in probability with an accompanying decrease in probability of the dot remaining in the ground vibrational state. We also present a simple model to estimate the effect of molecular size on the phonon emission of composite dimer molecules and compare the results with the complete analysis of ${\mathrm{C}}_{72}$ and the experimentally tested ${\mathrm{C}}_{140}$. In our approach we do not assume that the Hessians of the molecule are identical for different charge states. Our treatment is hence a generalization of the traditional phonon overlap calculations for coupled electron-photon transitions in solids.
Logic synthesis and circuit customization using extensive external don't-cares

Traditional digital circuit synthesis flows start from an HDL behavioral definition and assume that circuit functions are almost completely defined, making don't-care conditions rare. However, recent design methodologies do not always satisfy these assumptions. For instance, third-party IP blocks used in a system-on-chip are often overdesigned for the requirements at hand. By focusing only on the input combinations occurring in a specific application, one could resynthesize the system to greatly reduce its area and power consumption. Therefore we extend modern digital synthesis with a novel technique, called SWEDE, that makes use of extensive external don't-cares. In addition, we utilize such don't-cares present implicitly in existing simulation-based verification environments for circuit customization. Experiments indicate that SWEDE scales to large ICs with half-million input vectors and handles practical cases well.
The αD-Globin Gene Originated via Duplication of an Embryonic α-Like Globin Gene in the Ancestor of Tetrapod Vertebrates

Gene duplication is thought to play an important role in the co-option of existing protein functions to new physiological pathways. The globin superfamily of genes provides an excellent example of the kind of physiological versatility that can be attained through the functional and regulatory divergence of duplicated genes that encode different subunit polypeptides of the tetrameric hemoglobin protein. In contrast to prevailing views about the evolutionary history of the alpha-globin gene family, here we present phylogenetic evidence that the alpha(A)- and alpha(D)-globin genes are not the product of a single, tandem duplication of an ancestral globin gene with adult function in the common ancestor of extant birds, reptiles, and mammals. Instead, our analysis reveals that the alpha(D)-globin gene of amniote vertebrates arose via duplication of an embryonic alpha-like globin gene that predated the radiation of tetrapods. The important evolutionary implication is that the distinct biochemical properties of alpha(D)-hemoglobin (HbD) are not exclusively derived characters that can be attributed to a post-duplication process of neofunctionalization. Rather, many of the distinct biochemical properties of HbD are retained ancestral characters that reflect the fact that the alpha(D)-globin gene arose via duplication of a gene that had a larval/embryonic function. These insights into the evolutionary origin of HbD illustrate how adaptive modifications of physiological pathways may result from the retention and opportunistic co-option of ancestral protein functions.
Characterization and regulation of the latent transforming growth factor-β complex secreted by vascular pericytes

Transforming growth factor-beta (TGF-beta) stimulates the accumulation of extracellular matrix in renal and hepatic disease. Kidney glomerular mesangial cells (GMC) and liver fat-storing cells (FSC) produce latent of inactive TGF-beta. In this study, we characterized the latent TGF-beta complexes secreted by these cells. Human FSC produce a single latent TGF-beta complex, predominantly of the TGF-beta 1 isoform, whereas GMC secrete multiple complexes of latent TGF-beta, containing beta 1 and beta 2 isoforms. At least four forms were identified in GMC using ion exchange chromatography, including a peak not previously described in other cell types which eluted at 0.12 M NaCl, and predominantly of the beta 2 isoform. Both cell types secrete the latent TGF-beta 1 binding protein of 190 kDa, as part of a high molecular weight TGF-beta complex. Epidermal growth factor stimulates the secretion of latent TGF-beta and latent TGF-beta binding protein in both cell types. Secretion of latent TGF-beta in both cell types was found to be associated with secretion of decorin. This study shows that vascular pericytes from the kidney and the liver have distinctly different profiles of latent TGF-beta complexes, with GMC secreting a unique form of latent TGF-beta 2. The regulatory effect of epidermal growth factor and platelet-derived growth factor has potential implication for the pathophysiology of liver regeneration and chronic liver and kidney diseases.
A buried polar interaction can direct the relative orientation of helices in a coiled coil.

Coiled coils consist of bundles of two or more α-helices that are aligned in a parallel or an antiparallel relative orientation. The designed peptides, Acid-p1 and Base-p1, associate in solution to form a parallel, heterodimeric two-stranded coiled coil [O'Shea, E. K., Lumb, K. J., and Kim, P. S. (1993) Curr. Biol. 3, 658]. The buried interface of this complex is formed by hydrophobic Leu residues, with the exception of an Asn residue from each strand that is positioned to engage in a buried polar interaction. Substitution of these buried Asn residues by Leu residues results in a loss of structural uniqueness, as evidenced by a lack of a particular helix orientation in the Acid−Base coiled-coil complex [Lumb, K. J., and Kim, P. S. (1995) Biochemistry 34, 8642]. Here, we alter the positions of the Asn residues in the Acid and Base peptides such that a buried polar interaction is only expected to occur when the helices are in an antiparallel orientation. The resulting peptides, Acid-a1 and Base-a1, associat...
Challenges for Pervasive RFID-Based Infrastructures

The success of RFID in supply chain management is leading many to consider more personal and pervasive deployments of this technology. Unlike industrial settings, however, deployments that involve humans raise new and critical problems related to privacy, security, uncertainty, and a more diverse and evolving set of applications. At the University of Washington, we are deploying a building-wide RFID-based infrastructure with hundreds of antennas and thousands of tags. Our goal is to uncover the issues of pervasive RFID deployments and devise techniques for addressing these issues before such deployments become common place. In this paper, we present the challenges encountered and lessons learned during a smaller-scale pilot deployment of the system. We show some preliminary results and, for each challenge, discuss how we addressed it or how we are planning on addressing it
A mixed-space approach to first-principles calculations of phonon frequencies for polar materials.

We propose a mixed-space approach using the accurate force constants calculated by the direct approach in real space and the dipole–dipole interactions calculated by linear response theory in reciprocal space, making the accurate prediction of phonon frequencies for polar materials possible using the direct approach as well as linear response theory. As examples, by using the present approach, we predict the first-principles phonon properties of the polar materials α-Al2O3, MgO, c-SiC, and h-BN, which are in excellent agreement with available experimental data. (Some figures in this article are in colour only in the electronic version)
Myeloma wrecks T reg

Comment on Prabhala et al, page [300][1] Multiple myeloma is associated with a deranged immune system, which is thought to be attributed to myeloma infiltration and interference of the bone marrow. Now, Prabhala and colleagues show that dysfunctional Treg cells might also contribute to the
Zn2+ current is mediated by voltage-gated Ca2+ channels and enhanced by extracellular acidity in mouse cortical neurones.

1Mammalian neuronal voltage-gated Ca2+ channels have been implicated as potential mediators of membrane permeability to Zn2+. We tested directly whether voltage-gated Ca2+ channels can flux Zn2+ in whole-cell voltage-clamp recordings from cultured murine cortical neurones. 2In the presence of extracellular Zn2+ and no Na+, K+, or other divalent cations, a small, non-inactivating, voltage-gated inward current was observed exhibiting a current-voltage relationship characteristic of high-voltage activated (HVA) Ca2+ channels. Inward current was detectable at Zn2+ levels as low as 50 μm, and both the amplitude and voltage sensitivity of the current depended upon Zn2+ concentration. This Zn2+ current was sensitive to blockade by Gd3+ and nimodipine and, to a lesser extent, by ω-conotoxin GVIA. 3Zn2+ could permeate Ca2+ channels in the presence of Ca2+ and other physiological cations. Inward currents recorded with 2 mm Ca2+ were attenuated by Zn2+ (IC50= 210 μm), and currents recorded with Zn2+ were unaffected by up to equimolar Ca2+ concentrations. Furthermore, the Zn2+-selective fluorescent dye Newport Green revealed a depolarisation-activated, nimodipine-sensitive Zn2+ influx into cortical neurones that were bathed in a physiological extracellular solution plus 300 μm ZnCl2. 4Surprisingly, while lowering extracellular pH suppressed HVA Ca2+ currents, Zn2+ current amplitude was affected oppositely, varying inversely with pH with an apparent pK of 7·4. The acidity-induced enhancement of Zn2+ current was associated with a positive shift in reversal potential but no change in the kinetics or voltage sensitivity of channel activation. 5These results provide evidence that L- and N-type voltage-gated Ca2+ channels can mediate Zn2+ entry into cortical neurones and that this entry may be enhanced by extracellular acidity.
Finiteness of orbit structure for real flag manifolds

Let G be a reductive real Lie group, σ an involutive automorphism of G, and L=G σ the fixed point set of σ. It is shown that G has only finitely many L-conjugacy classes of parabolic subgroups, so if P is a parabolic subgroup of G then there are only finitely many L-orbits on the real flag manifold G/P. This is done by showing that G has only finitely many L-conjugacy classes of σ-stable Cartan subgroups. These results extend known facts for the case where G is a complex group and L is a real form of G.
Methylphenidate enhances brain activation and deactivation responses to visual attention and working memory tasks in healthy controls.

Methylphenidate (MPH) is a stimulant drug that amplifies dopamineric and noradrenergic signaling in the brain, which is believed to underlie its cognition enhancing effects. However, the neurobiological effects by which MPH improves cognition are still poorly understood. Here, functional magnetic resonance imaging (fMRI) was used together with working memory (WM) and visual attention (VA) tasks to test the hypothesis that 20 mg oral MPH would increase activation in the dorsal attention network (DAN) and deactivation in the default mode network (DMN) as well as improve performance during cognitive tasks in healthy men. The group of subjects that received MPH (MPH group; N = 16) had higher activation than the group of subjects who received no medication (control group: N = 16) in DAN regions (parietal and prefrontal cortex, regions increasingly activated with increased cognitive load) and had increased deactivation in the insula and posterior cingulate cortex (regions increasingly deactivated with increased cognitive load) and these effects did not differ for the VA and the WM tasks. These findings provide the first evidence that MPH enhances activation of the DAN whereas it alters DMN deactivation. This suggests that MPH (presumably by amplifying dopamine and noradrenergic signaling) modulates cognition in part through its effects on DAN and DMN.
Nuclear quadrupole resonance

The subject of nuclear quadrupole resonance is reviewed. Theoretical aspects are discussed first: electric quadrupole moment, electric field gradient, nuclear quadrupole resonance, and methods for measuring quadrupole coupling constants (pure quadrupole resonance, Zeeman effect, nuclear magnetic resonance, microwave spectrum, Moessbauer spectroscopy, other techniques). Factors affecting the resonance signal include static and dynamic influences on the line width and the position of the resonance signal. Instrumentation is briefly described. The correlation of nuclear quadrupole coupling constants with molecular structure is treated. Applications to halides (Group III, Group IV, transition metals, hexahalides in heavy atoms, etc.), nitrogen quadrupole resonance, minerals (chemical and structural properties, order--disorder phenomena), and quantitative analysis are examined. 6 figures, 7 tables, 77 references. (RWR)
Subcalcic diopsides from kimberlites: Chemistry, exsolution microstructures, and thermal history

Twenty-six subcalcic diopside megacrysts (Ca/(Ca+ Mg)) = 0.280–0.349, containing approximately 10 mol% jadeite, from 15 kimberlite bodies in South Africa, Botswana, Tanzania, and Lesotho, have been characterized by electron microprobe analysis, X-ray-precession photography, and transmission electron microscopy. Significant exsolution of pigeonite was observed only in those samples for which Ca/(Ca+Mg)≦0.320. The exsolution microstructure consists of coherent (001) lamellae with wavelengths ranging from 20 to 31 nm and compositional differences between the hosts and lamellae ranging from 10 to 30 mol% wollastonite. These observations suggest that the exsolution reaction mechanism was spinodal decomposition and that the megacrysts have been quenched at various stages of completion of the decomposition process.
Supporters and survivors: the people without AIDS

Over the past 10 years the AIDS crisis has produced a large volume of writing. Much of this is documentary. Dozens of studies of AIDS from various clinical and political perspectives have been complemented by just as many published diaries, autobiographies, novels, plays, and poems. A few of these works have risen to the surface not only as extraordinarily valuable testimonies to the changes AIDS has wrought in individual and collective life but also as first-rate literary works, worth reading because beyond their immediate purposes they articulate with extraordinary lucidity and compassion some deep truths about the human--and the modern--condition. Paul Monette's Borrowed Time is among the most distinctive of those. It speaks not only for the community of people with AIDS and those who support them but for a generation.
Generalized treatment of NMR spectra for rapid chemical reactions

Application of NMR spectroscopy to fast irreversible reactions (t1/2 < 0.7 s) has been hampered by limitations in instrumentation and general methods for modeling the complicated spectra that result. Analytical descriptions of nuclear spin dynamics during fast reactions, first solved by Ernst and coworkers, are limited to first-order reaction kinetics. We demonstrate that numeric methods enable simulation of NMR spectra for fast reactions having any form of rate law. Simulated stopped-flow NMR spectra are presented for a variety of common kinetic scenarios including reversible and irreversible reactions of first and second-order, multistep reactions, and catalytic transformations. The simulations demonstrate that a wealth of mechanistic information, including reaction rates, rate laws, and the existence of intermediates, is imbedded in a single NMR spectrum. The sensitivity of modern NMR instrumentation along with robust methods for simulating and fitting kinetic parameters of fast reactions make stopped-flow NMR an attractive method for kinetic studies of fast chemical reactions. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part A 30A: 165–183, 2007.
Scaling the Teflon Peaks: Rock type and the generation of extreme relief in the glaciated western Alaska Range

[1] Parts of the Alaska Range (Alaska, USA) stand in prominent exception to the “glacial buzzsaw hypothesis,” which postulates that terrain raised above the ELA is rapidly denuded by glaciers. In this paper, we discuss the role of a strong contrast in rock type in the development of this exceptional terrain. Much of the range is developed on pervasively fractured flysch, with local relief of 1000–1500 m, and mean summit elevations that are similar to modern snow line elevations. In contrast, Cretaceous and Tertiary plutons of relatively intact granite support the range's tallest mountains (including Mt. McKinley, or Denali, at 6194 m), with 2500–5000 m of local relief. The high granitic peaks protrude well above modern snow lines and support many large glaciers. We focus on the plutons of the Denali massif and the Kichatna Mountains, to the west. We use field observations, satellite photos, and digital elevation data to demonstrate how exhumation of these plutons affects glacier longitudinal profiles, the glacial drainage network, and the effectiveness of periglacial processes. In strong granite, steep, smooth valley walls are maintained by detachment of rock slabs along sheeting joints. These steep walls act as low-friction surfaces (“Teflon”), efficiently shedding snow. Simple scaling calculations show that this avalanching may greatly enhance the health of the modern glaciers. We conclude that, in places such as Denali, unusual combinations of rapid tectonic uplift and great rock strength have created the highest relief in North America by enhancing glacial erosion in the valleys while preserving the peaks.
ESTRADIOL INHIBITION OF DNA-3 H-THYMIDINE INCORPORATION IN CULTURED HUMAN FETAL EPIPHYSEAL CHONDROCYTES

ESTRADIOL INHIBITION OF DNA- 3 H-THYMIDINE INCORPORATION IN CULTURED HUMAN FETAL EPIPHYSEAL CHONDROCYTES
Locomotor effects of d-amphetamine and methylphenidate in young squirrel monkeys

The effects of d-amphetamine and methylphenidate upon the locomotor activity of six young squirrel monkeys were studied. While d-amphetamine produced a dose-related decrease in activity, methylphenidate produced no significant changes. Combined doses of the drugs, as well as a large dose of methylphenidate, produced no changes in locomotor activity that were related to methylphenidate.
Repeated exposure to aerosolized brevetoxin-3 induces prolonged airway hyperresponsiveness and lung inflammation in sheep.

Context: During a Florida red tide, brevetoxins (PbTxs) produced by Karenia brevis become aerosolized and can cause both immediate and prolonged airway symptoms in humans, especially in those with preexisting airway disease (e.g., asthma). Although environmental monitoring indicates that toxins remain airborne for up to 4 consecutive days, there is little information on airway responses after multiple-day exposures.Objectives: To delineate putative mechanisms leading to pulmonary dysfunction after PbTx exposure, we studied airway responses before and after multiple exposures to aerosol PbTx-3, the most potent PbTx produced, in nonallergic (healthy) and in allergic sheep, which serve as a surrogate for patients with compromised airways.Methods: Both groups were exposed to 20 breaths of increasing concentrations of PbTx-3 (30–300 pg/mL) for 4 consecutive days. Airway responsiveness to carbachol (1 and 8 days after) and airway inflammation as assessed by bronchoalveolar lavage (0 and 7 days after) were measu...
The maximal degree of dependence among inputs, outputs, and consumer goods☆

Abstract The maximal degree of dependence among consumer goods, inputs, or outputs is determined by the ratio of the arithmetic mean to the geometric mean of the latent roots of the independence transformation. These roots are the income elasticities of the transformed consumer goods or the Divisia elasticities of the transformed inputs or outputs. The maximum is attained when all observed goods have the same own-price elasticity.
Effect of Glutathione Depletion on Sunburn Cell Formation in the Hairless Mouse

Cutaneous protection against ultraviolet B (UVB) radiation damage by endogenous glutathione (GSH) was evaluated in the epidermis of the hairless mouse by measuring the influence of GSH depletion on sunburn cell (SBC) formation. Cellular GSH exerts antioxidant effects and recent studies have suggested a role for oxygen radicals in the production of SBC. Hairless mice (Skh/h 1) received oral treatment with buthionine S,R-sulfoximine (BSO), an irreversible inhibitor of gamma-glutamylcysteine synthetase, to deplete cutaneous GSH; 4 d later their ears were exposed to UVB radiation. BSO treatment significantly reduced GSH levels in the epidermis to 10-15% of control levels. Twenty-four hours after UVB exposure, SBC counts in the ears of animals with and without BSO treatment were measured, and those exposed to UVB were found to have increased. Greater numbers of SBC were found in the ears of BSO-treated mice exposed to 15 or 20 mJ/cm2 UVB, than in non-BSO-treated mice exposed to the same UVB doses. At higher UVB doses, there were no statistically significant differences between the groups. The results show that endogenous GSH provides the epidermis with measurable protection against injury by low or moderate UVB doses.
Characterization of a Local Folding Event of the Tetrahymena Group I Ribozyme: Effects of Oligonucleotide Substrate Length, pH, and Temperature on the Two Substrate Binding Steps†

Binding of the Tetrahymena group I ribozyme's oligonucleotide substrate occurs in two steps: P1 duplex formation with the ribozyme's internal guide sequence which forms an "open complex" is followed by docking of the P1 duplex into tertiary interactions within the catalytic core which forms a "closed complex". By systematically varying substrate length, pH, and temperature, we have identified conditions under which P1 duplex formation, P1 docking, or the chemical cleavage step limits the rate of the ribozyme reaction. This has enabled characterization of the individual steps as a function of substrate length, pH, and temperature, leading to several conclusions. (1) The rate constant for formation of the open complex is largely independent of substrate length, pH, and temperature, analogous to that of duplex formation in solution. This extends previous results suggesting that open complex formation entails mainly secondary structure formation and strengthens the view that the second binding step, P1 docking, represents a simple transition from secondary to tertiary structure in the context of an otherwise folded RNA. (2) The temperature dependence of the rate constant for P1 docking yields a negative activation entropy, in contrast to the positive entropy change previously observed for the docking equilibrium. This suggests a model in which tertiary interactions are not substantially formed in the transition state for P1 docking. (3) Shortening the substrate by three residues decreases the equilibrium constant for P1 docking by 200-fold, suggesting that the rigidity imposed by full-length duplex formation facilitates formation of tertiary interactions. (4) Once docked, shortened substrates are cleaved at rates within 3-fold of that for the full-length substrate. Thus, all the active site interactions required to accelerate the chemical cleavage event are maintained with shorter substrates. (5) The rate constant of approximately 10(3) min(-1) obtained for P1 docking is significantly faster than the other steps previously identified in the tertiary folding of this RNA. Nevertheless, P1 docking presumably follows other tertiary folding steps because the P1 duplex docks into a core that is formed only upon folding of the rest of the ribozyme.
The Role of Demographics and Opportunities to Learn in Predicting Performance on a High-Stakes Test

Abstract High-stakes testing has emerged as a central feature of the educational landscape in primary and secondary schools in the United States. Despite this prominence, there is a paucity of guidance available to practitioners on how they can best make predictions about student performance based on available test data. While achievement gaps based on demographics are widely known, less commonly analyzed are differences in opportunities to learn. Results from the first group of students in Massachusetts required to take a state-created exam in order to graduate from high school indicated that both demographics and courses taken were significant predictors of performance. Recommendations for analyzing test data and for promoting more comprehensive and culturally responsive assessment and curriculum practices are offered.
Toward Reliable Composites An Examination of Design Methodology

The current deterministic design approach is reviewed, and an alternate reliability-based design procedure is described which is more appropriate to the distinct behavioral characteristics of composite materials. The proposed procedure treats: load generation, material characterization, reliability apportionment, scaling, and complexity.
AVOA Algorithm For Fracture Characterization

Nowadays the analysis of azimuthal variation in reflection coefficients or AVOA analysis (Amplitude Versus Offset and Azimuth) is widely applied for detection and mapping highly fractured zones with azimuthally-oriented vertical cracks. Based on Ruger’s equations for reflection coefficients in HTI medium, AVOA technique gives, in general case, two symmetry directions of HTI medium without any formal indication which of these two orthogonal directions points to the symmetry axis and which to the fracture strike. Therefore some additional information is required besides reflection coefficients to resolve the ambiguity in fracture-direction estimation. We develop a new computational algorithm for P-wave AVOA analysis (improved in comparison with existing technique) which resolves the ambiguity using only reflection coefficients. The algorithm makes use of the third term in Ruger’s approximation for determining symmetry-axis and fracture-strike azimuths uniquely. We test the algorithm in synthetic and field data.
Using unreliable virtual hardware to inject errors in extreme-scale systems

Fault tolerance is a key obstacle to next generation extreme-scale systems. As systems scale, the Mean Time To Interrupt (MTTI) decreases proportionally. As a result, extreme-scale systems are likely to experience higher rates of failure in the future. To mitigate this, significant research has focused on developing and validating fault tolerance techniques. However, evaluating techniques for withstanding hardware failures at large scale is challenging because replicating those failures on small-scale testbeds is difficult. In this paper, we propose a virtualization-based framework for creating testbeds with unreliable virtual hardware. Our proposed approach allows for comprehensive evaluation of fault tolerance techniques in a broad range of failure regimes. Although there are many other approaches for mimicking unreliable hardware, none of them offer the breadth, scalability, and performance that a virtualization-based solution does.
Tensile deformation and failure of poly(p-phenylene terephthalamide) fibres

Abstract The tensile deformation and failure of a wide range of poly(p-phenylene terephthalamide) fibres is investigated. Fibre tensile modulus and tensile strength can be varied widely through simple processing variations, yet the fibres are found to exhibit similar non-linear elastic deformation responses as elucidated in stress perturbation experiments. An asymptotic modulus characteristic of the local orientation in the fibres is determined and is found to correlate well with the tensile strength of the fibres in accordance with straightforward shear failure criteria. The tensile failure of these fibres is thus dominated by the inherent strength anisotropy of linear chain polymers and the imperfect orientation in the fibres.