cssi/SciSciGPT-SciSciNet huggingface dataset:
Structure, function, and post-translational regulation of the catalytic and modifier subunits of glutamate cysteine ligase

Glutathione (GSH) is a tripeptide composed of glutamate, cysteine, and glycine. The first and rate-limiting step in GSH synthesis is catalyzed by glutamate cysteine ligase (GCL, previously known as gamma-glutamylcysteine synthetase). GCL is a heterodimeric protein composed of catalytic (GCLC) and modifier (GCLM) subunits that are expressed from different genes. GCLC catalyzes a unique gamma-carboxyl linkage from glutamate to cysteine and requires ATP and Mg(++) as cofactors in this reaction. GCLM increases the V(max) and K(cat) of GCLC, decreases the K(m) for glutamate and ATP, and increases the K(i) for GSH-mediated feedback inhibition of GCL. While post-translational modifications of GCLC (e.g. phosphorylation, myristoylation, caspase-mediated cleavage) have modest effects on GCL activity, oxidative stress dramatically affects GCL holoenzyme formation and activity. Pyridine nucleotides can also modulate GCL activity in some species. Variability in GCL expression is associated with several disease phenotypes and transgenic mouse and rat models promise to be highly useful for investigating the relationships between GCL activity, GSH synthesis, and disease in humans.
Experimental Evaluation and Optimization of Structures for Lossless Ion Manipulations for Ion Mobility Spectrometry with Time-of-Flight Mass Spectrometry

We report on the performance of structures for lossless ion manipulation (SLIM) as a means for transmitting ions and performing ion mobility separations (IMS). Ions were successfully transferred from an electrospray ionization (ESI) source to the TOF MS analyzer by means of a linear SLIM, demonstrating lossless ion transmission and an alternative arrangement including a 90° turn. First, the linear geometry was optimized for radial confinement by tuning RF on the central “rung” electrodes and potentials on the DC-only guard electrodes. Selecting an appropriate DC guard bias (2–6 V) and RF amplitude (≥160 Vp-p at 750 kHz) resulted in the greatest ion intensities. Close to ideal IMS resolving power was maintained over a significant range of applied voltages. Second, the 90° turn was optimized for radial confinement by tuning RF on the rung electrodes and DC on the guard electrodes. However, both resolving power and ion transmission showed a dependence on these voltages, and the best conditions for both were ...
Intrinsic V- and Vo centers in single crystal SrO

Abstract The intrinsic V- center (a positive hole trapped at a cation vacancy) has been observed in single crystals of SrO following x-irradiation at 77 K. The ESR spectrum corresponds to a spin- 1 2 defect having axial symmetry with g‖ = 2.0012(3) and g⊥ = 2.0703(3). The concentration of V- centers was enhanced significantly by heating crystals in oxygen at 1000°C and rapidly quenching. Vo centers (two holes trapped at a cation vacancy) were also observed after x-irradiation at low temperature, with g‖ = 2.0011(3), g⊥ =2.0751(3), and D = 380.4(5) MHz.
C20: the smallest fullerene?

Abstract The structure of 20-atom carbon clusters has been studied using correlated ab initio calculations with large basis sets. SCF calculations predict a monocyclic, poly-acetylene structure to be the most stable from. In contrast, a “fullerene”-type, cage structure is the ground state conformer at the correlated level.
Adaptive runlength coding

Runlength coding is the standard coding technique for block transform-based image/video compression. A block of quantized transform coefficients is first represented as a sequence of RUN/LEVEL pairs that are then entropy coded-RUN being the number of consecutive zeros and LEVEL being the value of the following nonzero coefficient. We point out the inefficiency of conventional runlength coding and introduce a novel adaptive runlength (ARL) coding scheme that encodes RUN and LEVEL separately using adaptive binary arithmetic coding and simple context modeling. We aim to maximize compression efficiency by adaptively exploiting the characteristics of block transform coefficients and the dependency between RUN and LEVEL. Coding results show that with the same level of complexity, the proposed ARL coding algorithm outperforms the conventional runlength coding scheme by a large margin in the rate-distortion sense.
Coordinating robotic sensors in a complex environment for data collection and object recognition

Most robotic systems used today rely heavily on prior knowledge of the location of specific objects in the workspace. Uncertainty occurs even in these `fixed' manufacturing workspaces, where over time, the precision about the knowledge of the location of objects degrades. Therefore, the entire system must be reprogrammed when adjustments are made. A robot that is able to adapt to changes automatically, must be able to sense its surroundings and identify objects that are encountered. The objective of this work was to design control algorithms that would enable a multisensor robotic system to perform specified tasks in a real world environment. The robotic system presented in this paper operates with little or no prior knowledge. Therefore the robot is given the task of collecting information about its surroundings. Data may be collected for the purpose of object recognition, environment mapping or object manipulation. The main sensing capabilities chosen for this system are machine vision and tactile force sensing. Each sensing technique has its relative advantages and disadvantages. Therefore, it is best to combine and coordinate sensing techniques depending on the work environment and the task requirements. Experiments are performed to show that the algorithms allow the system to meet the goals of safety, accuracy and economical use of computational resources.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Dynorphin reduces calcium-dependent action potential duration by decreasing voltage-dependent calcium conductance

The opioid peptide dynorphin decreased somatic calcium-dependent action potential duration in a portion of mouse dorsal root ganglion (DRG) neurons without altering resting membrane potential or conductance. Dynorphin action was antagonized by naloxone. Responses of DRG neurons to dynorphin differed from responses to the opioid peptides leucine-enkephalin, which binds preferentially to delta-opiate receptors, and morphiceptin, which binds preferentially to mu-opiate receptors. Firstly, many DRG neurons responded to dynorphin but not to leucine-enkephalin or morphiceptin. Secondly, dynorphin responses, unlike leucine-enkephalin or morphiceptin responses, persisted following intracellular injection of cesium, a potassium channel blocker. We suggest that dynorphin acts at an opiate receptor distinct from mu- and delta-receptors and that this receptor is coupled to a voltage-dependent calcium channel.
John Grierson and the G.P.O. Film Unit, 1933–1939

(1983). John Grierson and the G.P.O. Film Unit, 1933–1939. Historical Journal of Film, Radio and Television: Vol. 3, No. 1, pp. 19-34.
High-Stakes Testing in the Warm Heart of Africa:The Challenges and Successes of the Malawi National Examinations Board

In the United States, tests are held to high standards of quality. In developing countries such as Malawi, psychometricians must deal with these same high standards as well as several additional pressures such as widespread cheating, test administration difficulties due to challenging landscapes and poor resources, difficulties in reliably scoring performance assessments, and extreme scrutiny from political parties and the popular press. The
A goal interval programming model for resource allocation in a marine environmental protection program

Abstract A multidimensional “goal programming” model is developed to aid resource allocation decisions in the U. S. Coast Guard's Marine Environmental Protection (MEP) program. It is then extended to a model of “goal interval programming” (GIP ) type where exact values for the indicated goals, as in ordinary goal programming, are replaced by ranges. Deviations outside these ranges are also accommodated by piecewise linear functions with slopes that vary with distance from the goal intervals. Uses and generalizations are discussed in the context of applications to allocating manhours and planning the activities of the Coast Guard's MEP program.
Role of Interferon α (IFNα)-inducible Schlafen-5 in Regulation of Anchorage-independent Growth and Invasion of Malignant Melanoma Cells

IFNα exerts potent inhibitory activities against malignant melanoma cells in vitro and in vivo, but the mechanisms by which it generates its antitumor effects remain unknown. We examined the effects of interferon α (IFNα) on the expression of human members of the Schlafen (SLFN) family of genes, a group of cell cycle regulators that mediate growth-inhibitory responses. Using quantitative RT-real time PCR, we found detectable basal expression of all the different human SLFN genes examined (SLFN5, SLFN11, SLFN12, SLFN13, and SLFN14), in malignant melanoma cells and primary normal human melanocytes, but SLFN5 basal expression was suppressed in all analyzed melanoma cell lines. Treatment of melanoma cells with IFNα resulted in induction of expression of SLFN5 in malignant cells, suggesting a potential involvement of this gene in the antitumor effects of IFNα. Importantly, stable knockdown of SLFN5 in malignant melanoma cells resulted in increased anchorage-independent growth, as evidenced by enhanced colony formation in soft agar assays. Moreover, SLFN5 knockdown also resulted in increased invasion in three-dimensional collagen, suggesting a dual role for SLFN5 in the regulation of invasion and anchorage-independent growth of melanoma cells. Altogether, our findings suggest an important role for the SLFN family of proteins in the generation of the anti-melanoma effects of IFNα and for the first time directly implicate a member of the human SLFN family in the regulation of cell invasion.
Oligocene-Miocene Antarctic continental weathering record and paleoclimatic implications, Cape Roberts drilling Project, Ross Sea, Antarctica

Abstract The bulk chemistry of mudrocks in Ross Sea drillcores on the Antarctic inner shelf is re-evaluated to extract records of continental paleotemperatures and ice extent. The chemical index of alteration (CIA) of the sedimentary sequence derived from the composite of the Cape Roberts cores changes in accordance with pCO 2 [Pagani, M., Zachos, J.C., Freeman, K.H., Tipple, B., Bohaty, S., 2005. Marked change in atmospheric carbon dioxide concentrations during the Paleogene, Science 309, 600–603]. The (K 2 O + Na 2 O)/Al 2 O 3 molar ratio of the mudrocks is used as a mean summer temperature proxy for continental Antarctica and it shows similarities with benthic Mg/Ca temperatures for the Southern Ocean [Billups, K., Schrag, D.P., 2002. Paleotemperatures and ice-volume of the past 27 myr revisited with paired Mg/Ca and stable isotope measurements on benthic foraminifera. Paleoceanography 17. doi 10.1029/2000PA000567]. The ratio is calibrated using intervals with significant pollen assemblages and the temperature proxy enables extrapolation of the paleoclimatic data over a larger portion of the drilled record. The CIA and (K + Na)/Al ratios support a persistent cooling and drying of climate through the Oligocene–Miocene transition. The results reinforce the strong coupling between East Antarctic continental temperatures and ice volume, with deep-sea temperatures and concentrations of atmospheric carbon over long timescales.
Glial cell line-derived neurotrophic factor enhances neurogenin3 gene expression and β-cell proliferation in the developing mouse pancreas

Glial cell line-derived neurotrophic factor (GDNF) is a factor produced by glial cells that is required for the development of the enteric nervous system. In transgenic mice that overexpress GDNF i...
Loss of P2Y2 Nucleotide Receptors Enhances Early Pathology in the TgCRND8 Mouse Model of Alzheimer's Disease

Neuroinflammation is a prominent feature in Alzheimer's disease (AD) and activation of the brain's innate immune system, particularly microglia, has been postulated to both retard and accelerate AD progression. Recent studies indicate that the G protein-coupled P2Y2 nucleotide receptor (P2Y2R) is an important regulator of innate immunity by assisting in the recruitment of monocytes to injured tissue, neutrophils to bacterial infections and eosinophils to allergen-infected lungs. In this study, we investigated the role of the P2Y2R in progression of an AD-like phenotype in the TgCRND8 mouse model that expresses Swedish and Indiana mutations in amyloid precursor protein (APP). Our results indicate that P2Y 2 R expression is upregulated in TgCRND8 mouse brain within 10 weeks of age and then decreases after 25 weeks of age, as compared to littermate controls expressing low levels of the P2Y 2 R. TgCRND8 mice with homozygous P2Y 2 R deletion survive less than 5 weeks, whereas mice with heterozygous P2Y 2 R deletion survive for 12 weeks, a time point when TgCRND8 mice are fully viable. Heterozygous P2Y 2 R deletion in TgCRND8 mice increased β-amyloid (Aβ) plaque load and soluble Aβ1-42 levels in the cerebral cortex and hippocampus, decreased the expression of the microglial marker CD11b in these brain regions and caused neurological deficits within 10 weeks of age, as compared to age-matched TgCRND8 mice. These findings suggest that the P2Y2R is important for the recruitment and activation of microglial cells in the TgCRND8 mouse brain and that the P2Y2R may regulate neuroprotective mechanisms through microglia-mediated clearance of Aβ that when lost can accelerate the onset of an AD-like phenotype in the TgCRND8 mouse.
New perspectives on APC control of cell fate and proliferation in colorectal cancer

Aberrant Wnt/β-catenin signaling following loss of the tumor suppressor adenomatous polyposis coli (APC) is thought to initiate colon adenoma formation. Considerable evidence for this model has come from mouse models of Apc truncation where nuclear β-catenin is detectable soon after loss of Apc. However, examination of tumors from familial adenomatous polyposis coli (FAP) patients has failed to confirm the presence of nuclear β-catenin in early lesions following APC loss despite robust staining in later lesions. This observation presents the possibility that colon adenomas arise through a β-catenin-independent function of APC. Additionally, there is a well established role for inflammation and specifically COX-2 and prostaglandin E2 in the progression of colorectal cancer. Here we review the current literature regarding the functions of APC in regulating WNT/β-catenin signaling as well as its control of intestinal cell fate and differentiation. Further, we provide a brief commentary on our current underst...
The Relationship Between Children's Temperament and Adjustment to Kindergarten and Head Start Settings

Adjustment to childhood group settings was studied as a function of individual temperament characteristics prior to beginning the group setting. A kindergarten (n = 52) and a Head Start (n = 23) sa...
Circular dichroism, binding and immunological studies on the interaction between spinach ferredoxin and glutamate synthase

Spinach ferredoxin and spinach ferredoxin-dependent glutamate synthase have been shown to form an electrostatically stabilized complex. Circular dichroism (CD) measurements indicate that conformational changes occur in one or both proteins during complex formation. A dissociation constant for the complex of 9 μM at low ionic strength was estimated from a titration of the CD changes. Ultrafiltration binding assays suggest that the likely ferredoxin: glutamate synthase stoichiometry of the complex is 2:1. Immunological experiments indicate that glutamate synthase has an antigenic determinant in common with two other spinach chloroplast ferredoxin-dependent enzymes, nitrite reductase and NADP+ reductase. The immunological data have been interpreted in terms of structurally similar binding sites for ferredoxin on all three enzymes.
Temperature-programmed desorption for the characterization of oxide catalysts

Abstract The application of temperature-programmed desorption (TPD) to the characterization of porous, oxide catalysts is discussed. First, the theory underlying TPD from porous materials is presented briefly and used to demonstrate that adsorption energetics are difficult to measure using TPD. Then, arguments are made that TPD of reactive probe molecules, especially when used in vacuum with controlled exposures, provides much more useful information about the catalyst, including site densities of the active phase of supported oxide catalysts and reaction pathways. Several examples from the literature are used in demonstration of this fact, including the determination of titania surface area in silica-supported titania catalysts, the determination of Bronsted-acid site densities in solid acids, and the elucidation of the reaction intermediates for the reaction of 2-propen-1-ol in an H-ZSM-5 zeolite.
High power laser heating of low absorption materials

A model is presented and confirmed experimentally that explains the anomalous behavior observed in continuous wave (CW) excitation of thermally isolated optics. Distributed Bragg Reflector (DBR) high reflective optical thin film coatings of HfO2 and SiO2 were prepared with a very low absorption, about 7 ppm, measured by photothermal common-path interferometry. When illuminated with a 17 kW CW laser for 30 s, the coatings survived peak irradiances of 13 MW/cm2, on 500 μm diameter spot cross sections. The temperature profile of the optical surfaces was measured using a calibrated thermal imaging camera for illuminated spot sizes ranging from 500 μm to 5 mm; about the same peak temperatures were recorded regardless of spot size. This phenomenon is explained by solving the heat equation for an optic of finite dimensions and taking into account the non-idealities of the experiment. An analytical result is also derived showing the relationship between millisecond pulse to CW laser operation where (1) the heating is proportional to the laser irradiance (W/m2) for millisecond pulses, (2) the heating is proportional to the beam radius (W/m) for CW, and (3) the heating is proportional to W / m ⋅ tan − 1 ( t / m ) in the transition region between the two.
An h.p.l.c. method for the quantitative determination of asulam, acetylasulam and sulphanilamide in peaches.

An analytical method has been developed for the determination of the herbicide, asulam [methyl(4‐aminobenzenesulphonyl)carbamate] and two metabolities, sulphanilamide and acetylasulam individually, in peaches. Asulam and acetylasulam were partitioned from an aqueous phase with ethyl ether, leaving behind more polar components which interfered with the analysis of these compounds. The sulphanilamide was next partitioned from the aqueous phase into ethyl acetate. Each fraction was then chromatographed on its own neutral alumina column, activity grade 1, and analysed by high performance liquid chromatography (h.p.l.c.) using a C‐18 reverse phase column. From peach samples fortified at the 0.10 p.p.m. level, recoveries averaged 72% (asulam), 100%. (acetylasulam) and 90% (sulphanilamide). No residues of these compounds were found in two studies of peaches harvested 0, 5, 10, 15 and 20 days following asulam treatment at 0–7.50 kg/ha.
Resource-mediated demographic variation during the midsummer succession of a cladoceran community

SUMMARY. 1. The midsummer succession of cladoceran zooplankton in Lake Texoma was examined by demographic characterization of lake populations and a parallel set of life table experiments in which the dominant cladoceran species were raised on naturally occurring lake phytoplankton at lake temperatures. Diaphanosoma leuchtenbergianum occurred throughout the study period (mid June-mid August 1981) but Daphnia parvula, D. galeata mendotae and Ceriodaphnia lacustris were rarely detected after 15 July. 2. Analyses of size structure and size-specific fecundity of the cladoceran populations showed that (1) size structure shifted to smaller individuals in mid July, (2) size-specific fecundity was relatively constant in the smaller size classes and was constant or declined in larger females of each species, and (3) size at maturation did not vary significantly during the study of any population. 3. Individual growth rates of the two Daphnia species and Ceriodaphnia in the life table experiments were significantly lower in mid July when populations were declining and when size structure of each population was more dominated by smaller Individuals. The reduction in individual growth rates was short-lived in the life table experiments; growth rates returned to pre-decline levels by the end of July. 4. Two effects of temporary reductions in individual growth rates when size-specific fecundity and size at maturation are constant are (1) that size structure is temporarily shifted to smaller individuals, and (2) the potential rate of population growth is reduced because of delays in reproduction. Because data on size structure and size-specific fecundity are commonly used to evaluate the relative effects of predators and resource changes on populations it is noteworthy that erroneous conclusions about the mechanism of population decline may be reached when individual growth rates vary.
Adaptive aeroelastic vibration suppression of a supersonic airfoil with flap

This paper concerns the flutter, post-flutter and adaptive control of a non-linear 2-D wing-flap system operating in supersonic/hypersonic flight speed regimes. An output feedback control law is implemented and its performance toward suppressing flutter and limit cycle oscillations (LCOs) as well as reducing the vibrational level in the subcritical flight speed range is demonstrated. This control law is applicable to minimum phase systems and we provide conditions for stability of the zero dynamics. The control objective is to design a control strategy to stabilize the pitch angle while adaptively compensating for uncertainties in all the aeroelastic model parameters. It is shown that all the states of the closed-loop system are asymptotically stable.
The role of system-justification motivation, group status and system threat in directing support for hate crimes legislation

Abstract We examine factors that explain variability in attitudes toward hate crimes legislation. We find that one's posture toward the current social system directs the conditions under which characteristics of hate crimes exert the most influence. System-justification motivation is negatively related to support for hate crimes legislation (Studies 1–3). This relation is partially mediated by perceptions of harm from hate crimes. Specifically, when hate crimes target low-status groups, system-justification motivation is negatively related to perceived harm and support for hate crimes legislation. Attitudes are unaffected when high-status groups are targeted. The status of the group targeted, perceptions of hate crimes as representative of the status quo, and temporarily enhanced feelings of system threat moderate this relation (Studies 2–4).
Mitotic activity and nucleic acid precursor incorporation in denervated and innervated limb stumps of axolotl larvae.

Mitotic activity and DNA and RNA precursor incorporation were compared in innervated regenerating limbs and in denervated, nonregenerating limbs on days 8 and 9 post-amputation. Innervated limbs had well-developed cone stage blastemas which showed high cellular mitotic indices and H3-thymidine labeling indices of 0.40–0.50 and H3-uridine labeling indices of 0.50–0.75. In contrast, denervated limbs showed dedifferentiated cells distally under thickened wound epithelia, but essentially no mitotic activity and no blastema formation. These dedifferentiated cells showed lower levels of H3-thymidine (0.10 index) and H3-uridine (0.50) incorporation than regenerating limbs. Labeling indices of wound epithelia are also compared.
A holographic phase-shifting interferometer technique to measure in-plane distortion

We describe the use of holographic phase-shifting interferometry (HPSI) to measure in-plane distortion of a substrate in which a shallow grating, produced by interferometric lithography, has been etched. The diffractive metrology inherent in HPSI should enable one to study process-induced distortions down to the level of a few nanometers. We used HPSI to investigate distortion introduced by the anodic bonding of silicon nitride membranes to Pyrex frames in x-ray lithography masks. This was part of an effort to develop an inverted x-ray mask configuration. The HPSI technique gave quantitative measurements of the linear and nonlinear components of distortions in one-dimension. The high levels of distortion found were presumably introduced by the high temperatures used in anodic bonding, combined with the asymmetric manner in which the membranes were brought into contact with the Pyrex frame. The comprehensive, quantitative measurement of distortion provided by HPSI should enable us to modify the mask making...
Photosynthetic activity during stress

Krieg, D.R., 1983. Photosynthetic activity during stress. Agric. Water Manage., 7: 249–263. Developmental and physiological limitations imposed by water stress upon photosynthetic activity of green plants and the effects on growth rate and yield are addressed. Photosynthetic activity is defined as a function of leaf area development, photosynthetic rate, and source-sink ratio responses. Leaf area development response to stress is defined as a function of growth habit differences on leaf number and blade size. Derived relationships suggest that whole plant leaf area is very sensitive to stress with differences between determinate and indeterminate plants in the source of the reductions. Indeterminate plants such as cotton (Gossypium hirsutum L.) tend to reduce leaf numbers; whereas, determinate plants reduce blade area. Genotypic variation exists in sorghum (Sorghum bicolor L. Moench) as to the extent of the reduction in leaf area development and retention. The photosynthetic rate is also sensitive to water stress. The cause of the response is explained on a biochemical rather than a diffusion-dependent basis. Genotypic variation in the photosynthesis per unit leaf conductance ratios for sorghum and cotton are suggested as possible means to increase water use efficiency. The relative sensitivity of the source compared with the sink is explored. Both leaf area and photosynthetic rate are reduced by stress, resulting in large reductions in total dry matter accumulation rates and final yields. In sorghum, stress prior to flowering results in a greater reduction in panicle differentiation and potential seed number than in leaf area. Additionally, stress reduces the efficiency of the existing leaf area through photosynthetic rate reductions. In cotton, leaf area is reduced more than fruit numbers per plant. The efficiency of the existing leaf area actually increases and the harvest index increases. Large genetic variation exists in almost every photosynthetic activity parameter examined, offering promise for yield improvement for dryland conditions.
Multi-scale modeling of elastic response of three-dimensional voxel-based microstructure datasets using novel DFT-based knowledge systems

Abstract In this paper, we present a novel approach for predicting the elastic fields in three-dimensional voxel-based microstructure datasets subjected to uniform periodic boundary conditions. This new formalism has its theoretical roots in the statistical continuum theories developed originally by Kroner. However, in the approach described by Kroner the terms in the series were established by selecting a reference medium and numerically evaluating a complex series of nested convolution integrals. This approach is largely hampered by the principal value problem and exhibits high sensitivity to the properties of the selected reference medium. In the present work, we have recast the same series expressions into much more computationally efficient representations using discrete Fourier transforms (DFTs). The main advantage of the new DFT-based framework is that it allows easy calibration of Kroner’s expansions to results from finite element methods, thereby overcoming all of the main obstacles associated with the principal value problem and the need to select a reference medium. Consequently, the DFT-based approach presented here produces much more accurate predictions. In this paper the new mathematical formalism is first presented in a generalized framework, and its viability is then demonstrated for a selected class of two phase composites.
An empirical analysis of behavioral intentions of single-occupant auto drivers to shift to high occupancy vehicles

Abstract The emphasis in transportation planning has recently changed from long-range, high-capital investments to short-term, low-cost transportation system improvements. The development of incentives for bus riding and carpooling, particularly for the work trip, plays a major role in this resource management process. This study is specifically designed to uncover factors which influence the intentions of the single-occupant auto commuters to switch to buses and carpools and to suggest operating policies consistent with the intent to encourage the use of high-occupancy vehicles. The single-occupant auto commuters are segmented into several potential ridesharing markets on the basis of their expressed intention to take a bus or a carpool if certain transportation system modifications were effected. Three groups of switchers are identified: those who are positively oriented towards taking a bus, those who would only switch to a carpool, and those who would consider either of the ridesharing modes. Bus convenience is the most important variable associated with the shift intention. Perceptions of carpool comfort do not appear to be important, rather, perceptions of carpool schedule flexibility, cost, safety and a short wait in traffic are prime factors associated with potential carpool shifting. Additional models involving mode satisfaction are reviewed and policies which enhance bus convenience and minimize waiting in traffic for carpools are suggested to recruit the potential ridesharers.
Possible horizontal transfer of Drosophila genes by the mite Proctolaelaps regalis

There is strong inferential evidence for recent horizontal gene transfer of the P (mobile) element to Drosophila melanogaster from a species of the Drosophila willistoni group. One potential vector of this transfer is a semiparasitic mite, Proctolaelaps regalis DeLeon, whose morphology, behavior, and co-occurrence with Drosophila are consistent with the properties necessary for such a vector. Southern blot hybridization, polymerase chain reaction (PCR) amplification, and DNA sequencing showed that samples of P. regalis associated with a P strain of D. melanogaster carried P element sequences. Similarly, Drosophila ribosomal DNA sequences were identified in P. regalis samples that had been associated with Drosophila cultures. These results have potentially important evolutionary implications, not only for understanding the mechanisms by which genes may be transferred between reproductively isolated species, but also for improved detection of some host-parasite and predator-prey relationships.
Theory of electron current rectification, switching, and a role of defects in molecular devices

Devices for nano- and molecular-sized electronics may allow for an efficient current rectification and switching. A few molecular scale devices are reviewed here on the basis of first-principles and model approaches. Current rectification by molecular quantum dots can produce the rectification ratio ≲100. Current switching due to conformational changes in the molecules is slow, on the order of a few kHz. Fast switching (∼1 THz) may be achieved, at least in principle, in a molecular quantum dot with attractive carrier-carrier interactions due to strong coupling with vibrational excitations. The observed switching in many cases is extrinsic, caused by changes in molecule-electrode geometry or metallic filament formation through the film.
Social subordination stress, behavior, and central monoaminergic function in female cynomolgus monkeys.

Abstract Background: Social subordination in female cynomolgus monkeys is stressful and activates the hypothalamic–pituitary–adrenal axis. In a previous experiment behavioral depression was observed in a subset of subordinates. Methods: In the experiment reported here behavioral and physiological indicators of stress were evaluated in dominant and subordinate female cynomolgus monkeys, and brain dopaminergic activity was assessed, as reflected in the prolactin response to haloperidol, a dopamine2 (D2) receptor antagonist. Results: Subordinates were aggressed more, spent more time in fearful scanning of the social environment, spent less time as the recipients of the active affiliative behavior of being groomed, had more variable heart rates in response to a novel environment, and were hypercortisolemic compared to dominants. Prolactin responses to haloperidol challenge were lower in subordinates than dominants, an observation consistent with the hypothesis that subordinate females have decreased D2 receptor function. Conclusions: These observations suggest that social subordination is stressful and may alter brain dopaminergic function in primates. The neurophysiological characteristics of social subordinates may contribute to their susceptibility to depression.
Empowering information and communication technologies in isolated areas: learning from the solar-net villages program in honduras

To reduce poverty caused by inequality of opportunities in isolated areas, many developing countries are now taking advantage of recent technical advances in information and communication technologies (ICTs) to enable the remote populations to enjoy the benefits of improved commerce, education, health, and other social services. This paper describes lessons learned from the Solar-Net Villages Program (or Aldeas Solares) of Honduras with respect to its early attempts to find technological solutions for providing ICT services to isolated areas and the government's ongoing efforts to balance the objective of assisting the most disadvantaged populations with the need to have sustainable services.
Modified natural nanoparticles as contrast agents for medical imaging

The development of novel and effective contrast agents is one of the drivers of the ongoing improvement in medical imaging. Many of the new agents reported are nanoparticle-based. There are a variety of natural nanoparticles known, e.g. lipoproteins, viruses or ferritin. Natural nanoparticles have advantages as delivery platforms such as biodegradability. In addition, our understanding of natural nanoparticles is quite advanced, allowing their adaptation as contrast agents. They can be labeled with small molecules or ions such as Gd(3+) to act as contrast agents for magnetic resonance imaging, (18)F to act as positron emission tomography contrast agents or fluorophores to act as contrast agents for fluorescence techniques. Additionally, inorganic nanoparticles such as iron oxide, gold nanoparticles or quantum dots can be incorporated to add further contrast functionality. Furthermore, these natural nanoparticle contrast agents can be re-routed from their natural targets via the attachment of targeting molecules. In this review, we discuss the various modified natural nanoparticles that have been exploited as contrast agents.
Loss of caspase-8 mRNA expression is common in childhood primitive neuroectodermal brain tumour/medulloblastoma

Upon binding of tumour necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL), the agonistic TRAIL receptors DR4 and DR5 activate caspase-8 leading to apoptosis. In primitive neuroectodermal brain tumour (PNET) cell lines, TRAIL-induced apoptosis was recently shown to correlate with caspase-8 mRNA expression (Grotzer MA, Eggert A, Zuzak TJ, et al. Oncogene 2000, 19, 4604-4610). In this study, we analysed the expression of the TRAIL death pathway in 27 primary PNET/medulloblastoma. As shown by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), all PNET/medulloblastoma evaluated expressed DR5, the adapter protein FADD and caspase-3, but only 48% expressed caspase-8. The mRNA expression of caspase-8 was significantly lower in primary PNET/medulloblastoma compared with normal brain samples. PCR revealed >75% methylation of the caspase-8 promoter region in three of seven PNET cell lines and in 55% of the primary PNET/medulloblastoma evaluated. In the PNET cell lines, the methylation status correlated with the caspase-8 mRNA expression. We conclude that loss of caspase-8 gene expression is common in PNET/medulloblastoma suggesting that suppression of death receptor induced apoptosis may play an important role in the pathogenesis of this common childhood brain tumour.
Potential for transfer and establishment of engineered genetic sequences

Abstract The transfer of recombinant DNA molecules from the introduced organism to natural populations of bacteria may be an important factor in assessing the outcomes of planned release of genetically engineered organisms into the environment. As genetic transfer is further investigated, it appears that the potential for genetic transfer between bacteria of the same and other species and genera is much greater than had been suspected. At present, efforts are being made to limit the range of ecological niches available to genetically engineered microorganisms. Genetic transfer of recombinant molecules to natural populations of bacteria would nullify these efforts.
Human Mesenchymal Stem Cells Form Multicellular Structures in Response to Applied Cyclic Strain

Mesenchymal stem cells (MSCs) are a component of many cardiovascular cell-based regenerative medicine therapies. There is little understanding, however, of the response of MSCs to mechanical cues present in cardiovascular tissues. The objectives of these studies were to identify a model system to study the effect of well-defined applied cyclic strain on MSCs and to use this system to determine the effect of cyclic equibiaxial strain on the cellular and cytoskeletal organization of MSCs. When exposed to 10%, 1 Hz cyclic equibiaxial strain for 48 h, MSCs remained viable, retained characteristic gene and protein markers, and rearranged to form multicellular structures defined as clusters and knobs. This novel observation of cluster (overlapping cells surrounded by radial cellular projections) and knob (more dome-like structure containing significantly more cells than a cluster) formation did not involve changes in cytoskeletal proteins and resulted from cellular rearrangements initiated within 8 h of applied strain. Observed cellular responses were found to be dependent on substrate coating, but not on cell density for the 8-fold ranges tested. This system can thus be used to study the mechanoresponse over hours to days of MSCs exposed to applied cyclic strain in the context of cell-cell and cell-matrix interactions.
Subsurface compositional modifications in NiCu alloys during high-temperature ion sputtering

Abstract Changes in the surface and subsurface compositions of Ni-40at%Cu alloys at temperatures between 25 and 700°C were measured in situ, using the ion scattering spectroscopy technique. Upon heating, Cu atoms segregated to the alloy surface; the enthalpy and entropy of Gibbsian adsorption were found to be −0.42 eV and −2.6k, respectively. During sputtering, the steady-state surface composition was noticeably temperature-dependent above ∼400°C, which could be interpreted in terms of significant contributions of the second atomic layer to the sputtered-atom flux. The coefficients for radiation-enhanced diffusion of Cu in the bombarded alloy were deduced from steady-state concentration profiles of compositionally-altered layers whose thicknesses depended strongly on temperature. A theoretical modeling of the phenomenon was also performed with the aid of a recently-developed kinetic model and the results were compared with the experimental observations.
Magma mixing, fractional crystallization and volatile degassing during the 1883 eruption of Krakatau volcano, Indonesia

Abstract The 1883 eruption of Krakatau volcano, Indonesia produced approximately 12.5 km3 (DRE) of magma, 90% rhyodacite, 4% mafic dacite, and 1% andesite (5% lithic material assumed). Melt compositions in the erupted products based on the study of glass inclusions and matrix glasses span a minimum range of 13 wt.% SiO2. Well defined linear trends of major elements have been successfully modelled by incremental fractional crystallization of plagioclase, pyroxene, and Fe-Ti oxides from andesitic parental magma to produce rhyodacite. This fractional crystallization model is supported by trace-element and isotopic data. The 1883 magma chamber was compositionally and thermally zoned with an upper portion of homogenous rhyodacite at a temperature of 880–890 °C overlying more mafic dacite at 890–913 °C, and andesite at 980–1000 °C. Mafic dacite represents a hybrid magma formed by mixing small amounts of andesite with larger amounts of evolved rhyodacite. Evidence for magma mixing consists of banded pumices, glass inclusions that are more mafic than whole rock and matrix glass compositions, heterogeneous matrix glass compositions, and disequilibrium phenocrysts of anorthite-rich plagioclase in rhyodacite and mafic dacite. The 1883 rhyodacitic magma was probably not water saturated until it reached a shallow depth in the crust of 4–5 km. Glass inclusions indicate pre-eruption dissolved volatile content in rhyodacite and mafic dacite of 4.0 ± 0.5 wt.%. Estimated sulfur discharge from erupted magma is 2.8 × 1012 g S, and estimated Cl discharge is 9.7 × 1012 g Cl. Two potential sources of additional sulfur from this eruption may be vaporization of seawater during entrance of pyroclastic flows into the sea, and degassing of nonerupted andesitic parental magma lying beneath evolved rhyodacitic magma in the zoned 1883 chamber.
Model-based fault diagnosis of a DC-DC boost converters using hidden Markov model

This paper introduces a hidden Markov model (HMM)-based fault diagnosis technique for DC-DC boost converter. Four HMMs are trained to model parameter variations in the power converters. Each HMM is created based on 14 visible states, which generates probability of each time step matching a signature fault pattern. The proposed method can cover multiple faults that may occur in any element of power electronic circuits. It can also achieve high precision of diagnosing for pre-defined faults in real-time. The simulation results demonstrate an accurate diagnosis performance using HMMs.
Integrating human factors principles into systems engineering

The objective of this paper is to examine current literature and to compile a guideline for integrating human factors principles into systems engineering. Each of the four suggested design stages — requirements acquisition, concept generation, preliminary, detailed — is characterized by a short description of the systems engineer's and the human factors engineer's roles and stage goals, the types of questions posed by the human factors engineer during the process, and suggested methods for integration between the two disciplines. The design process proposed in this paper is not intended to be a universal approach, but rather, a guideline for engineers regarding the overall design development process. The primary audience in this paper for this paper is systems engineers in the aerospace industry looking to better understand how to incorporate human factors into their designs.
Multiple mu receptors: evidence for mu2 sites in the guinea pig ileum.

The ability of morphine to inhibit the electrically induced contractions of the guinea pig ileum is mediated through the mu class of opioid receptors. However, recent studies have implied the existence of two subtypes of mu receptors in the brain (μ1 and μ2, which differ both biochemically and pharmacologically. The antagonist naloxonazine and the agonist oxymorphonazine selectively and irreversibly bind μ1 sites. Treatment of both rat and guinea pig brain homogenates with naloxonazine in vitro to selectively inhibit μ1 binding significantly decreased [3H]dihyromorphine binding, whereas binding in similarly treated guinea pig ileum longitudinal muscle—myenteric plexus was virtually unaffected (P<0.0005). Similarly, the actions of both drugs in the guinea pig ileum contraction assay were reversible. The findings imply that morphine's actions on the guinea pig ileum were mediated through the μ2 subtype of opioid receptor.
Electrochemistry and contact angles of an ionic liquid sessile droplet on films of monolayer-protected au nanoparticles

An unwalled electrochemical cell formed by a sessile droplet of 1-butyl-3-methylimidazolium hexafluorophosphate resting on electroactive surfacesself-assembled alkanethiolate monolayers, films of Au nanoparticles and of ferrocene cast from evaporated solution dropletsis used to investigate the voltammetry and surface energy of these electrode/ionic liquid interfaces. Auxiliary and quasi-reference 25-μm-diameter Pt wire electrodes are inserted into the top of the sessile droplet. The cyclic voltammetry of a film of hexanethiolate-protected Au140 nanoparticles shows that they undergo quantized double layer charging at the ionic liquid interface, accompanied by insertion of hexafluorophosphate anions into the nanoparticle film. The contact angle of the ionic liquid droplet resting on the nanoparticle film is observed to decrease when the gold electrode potential is controlled to oxidize the interface to the Au1401+ state. The increase in surface charge and the alteration in chemical composition of the oxidiz...
Experimental basis for multiple primary carcinogenesis by sex hormones: a review.

Several mechanisms of multiple tumor induction by sex hormones may be inferred from recent investigations of the mechanism of sex hormone action: a. Prolonged exposure of tissues containing estrogen receptor proteins to increased concentrations of a natural or synthetic estrogen with a high binding affinity for receptor protein may lead to excessive estrogen-receptor protein complex stimulation of nuclear-directed biosynthetic activities, and resynthesis of cytoplasmic receptor protein in excessive amounts, with resultant hyperplasia of the tissue. This excessive “priming” results in multiple tumors of the breast, or possibly breast and uterus. Testosterone induction of prostate adenocarcinoma has been reported. Such neoplasms may be highly hormone-dependent. Experimental verification of this concept by biochemical quantitation of androgen or estrogen receptor complexes in nuclei of target cells remains to be done. b. Estrogenic hormones act as mammary cocarcinogens after mammary epithelial tissues are exposed early in life to physical, chemical, or biologic mutagenic agents. Once neoplastic transformation of breast duct or terminal alveolar cells has occurred by any means, the development of one or more malignant neoplasms becomes dependent to a large extent on the rate of cellular replication induced by estrogens, along with insulin and other hormones. Estrogen antagonists and 16 alpha hydroxy metabolites of estradiol 17B (estriol) competing with estradiol for cytoplasmic receptors and for DNA binding in protein complexes with estradiol may reduce the incidence of neoplasms so induced in the breast. c. Neoplastically transformed cells originating in tissues such as skin may undergo genetic derepression, with inappropriate or ectopic biosynthesis of sex hormone receptor proteins, as shown by estrogen receptor content of human malignant melanoma, d. Cytoplasmic estrogenreceptor complexes may bind to nuclei of lymphocytes, muscle or other tissues devoid of cytoplasmic receptors. Therefore, receptor protein-hormone complexes may be transferred from neoplasms undergoing cytolysis to adjacent tissues.