cssi/SciSciGPT-SciSciNet huggingface dataset:
Rates of sterol synthesis and hydroxymethylglutaryl coenzyme A reductase levels, and the effects of cholest-4-en-3-one on these parameters, in the livers of inbred strains of mice.

Hereditary factors in inbred mouse strains affected the rate of sterol synthesis from acetate and the level of hydroxymethylglutaryl coenzyme A reductase in liver in two ways. During the forenoon, rates of sterol synthesis and levels of HMG-CoA reductase activity were two- to five-fold higher in C57L/J and DBA/2J mice than in mice of strains A/HeJ or SWR/J. Due to an apparent difference in the circadian cycle of the two strains, these differences between C57BL/6J and A/HeJ strains were not as great at 4:30 pm, and in some cases the relative order of the values was reversed at this time. Low doses of dietary cholest-4-en-3-one inhibited sterol synthesis and HMG-CoA reductase in livers of all strains tested, whereas high doses or prolonged feeding of the steroid caused a relatively rapid elevation of both sterol synthesis and enzyme activity to above normal levels in several mouse strains including C57L/J. Sterol synthesis and enzyme activity in strain A/HeJ mice were depressed by dietary cholest-4-en-3-one under all conditions tested except when the steroid was fed at a low level for a prolonged period. LAF1 offspring of the cross C57L/J×A/HeJ responded to dietary cholest-4-en-3-one as did the A/HeJ parental strain. Analysis of the effects of cholest-4-en-3-one upon sterol synthesis in backcross offspring of the mating LAF1/J×C57L/J did not permit precise estimation of the number of genes that determine the difference in response to the dietary steroid but did suggest that the number may be relatively small.
Characterization of the ketodienes formed in the oxidation of linoleate by lipoxidase

Abstract The oxidation products of ethyl linoleate, which have an absorption maximum at 277 mμ, have been isolated by column chromatography and thin-layer chromatography. Ultraviolet, near infrared, and infrared spectra and microchemical analysis for ester and ketone functions have indicated that the chromophore is a mixture of 9-keto-11,13-octadecadienoate and 13-keto-9,11-octadecadienoate. Reduction to the hydroxy compounds and subsequent dehydration yielded octadecatrienoate. The methods used required 1–10 mg. of sample which were isolated and purified via thin-layer chromatography.
Intercultural Dimensions of Communicating Masculinities

The concept and study of masculinities has been a complex and rigorous one. Numerous disciplines attempt to conceptualize men and masculinity and seemingly compound the elusive topic. However, it i...
Brain response to calorie restriction

Calorie restriction extends longevity and delays ageing in model organisms and mammals, opposing the onset and progression of an array of age-related diseases. These beneficial effects also extend to the maintenance of brain cognitive functions at later age and to the prevention, at least in rodents, of brain senescence and associated neurodegenerative disorders. In recent years, the molecular mechanisms underlying brain response to calorie restriction have begun to be elucidated, revealing the unanticipated role of a number of key nutrient sensors and nutrient-triggered signaling cascades in the translation of metabolic cues into cellular and molecular events that ultimately lead to increased cell resistance to stress, enhanced synaptic plasticity, and improved cognitive performance. Of note, the brain’s role in CR also includes the activation of nutrient-sensitive hypothalamic circuitries and the implementation of neuroendocrine responses that impact the entire organism. The present review addresses emerging molecular themes in brain response to dietary restriction, and the implications of this knowledge for the understanding and the prevention of brain disorders associated with ageing and metabolic disease.
Income taxation and the allocation of market labor

The allocation of work effort within the market economy will be unaffected by taxation if all returns from labor market activity are taxed equally. However, if the earnings from certain types of market employment are taxed at relatively lower rates, labor will shift into these areas until after-tax earnings are equal across all types of employment. This paper presents evidence suggesting that income taxation induces labor to move from high- to low-tax geographic areas and from wage and salaried jobs into self-employment activities. By affecting the allocation of market labor, the income tax generates a welfare loss in addition to that resulting from the tax’s effect on total work effort.
A boussinesq model of natural convection in the human eye and the formation of Krukenberg's spindle.

The cornea of the human eye is cooled by the surrounding air and by evaporation of the tear film. The temperature difference between the cornea and the iris (at core body temperature) causes circulation of the aqueous humor in the anterior chamber of the eye. Others have suggested that the circulation pattern governs the shape of the Krukenberg spindle, a distinctive vertical band of pigment on the posterior cornea surface in some pathologies. We modeled aqueous humor flow the human eye, treating the humor as a Boussinesq fluid and setting the corneal temperature based on infrared surface temperature measurements. The model predicts convection currents in the anterior chamber with velocities comparable to those resulting from forced flow through the gap between the iris and lens. When paths of pigment particles are calculated based on the predicted flow field, the particles circulate throughout the anterior chamber but tend to be near the vertical centerline of the eye for a greatest period of time. Further, the particles are usually in close proximity to the cornea only when they are near the vertical centerline. We conclude that the convective flow pattern of aqueous humor is consistent with a vertical pigment spindle. © 2002 Biomedical Engineering Society. PAC2002: 4266Ew, 8710+e, 8719Pp
Comfort issues in geriatric oncology.

T HE PROVISION of comfort has traditionally been viewed as an integral part of the nursing role. In early writings, Nightingale indicated a need to observe the sick to find ways of increasing not only health but comfort. ’ Bodnar and Pederson describe nursing as a “ . . .nurturative practice oriented to providing comfort and care in the presence of illness,“2 and Leininger includes comfort as one of the components in her listing of twenty-five “Caring Constructs.“3 Accepting the role of comforter, nurses have developed and refined an extensive repertoire of knowledge and skills to alleviate the suffering of their patients at times of physical and emotional distress.4 With such definitiveness in designating the act of comforting as inherent to the art of nursing, it would seem a simple task to identify comfort issues faced by the elderly cancer patient. However, two major gaps in the literature interfere with that task. First, a clear definition of what constitutes comfort is absent. Like caring, it remains a nebulous term open to many interpretations.5 Some authors refer to comfort or comforting as an element of caring, while others use the two terms synonymously. Fleming et al6 state that although it is the focus of care for advanced cancer patients, the concept of comfort is not adequately descriptive of specific patient needs or easily translated into nursing behaviors. Examples of nursing interventions specifically described as comfort behaviors are listed in Table 1. While some nursing care themes do emerge, the range of interpretations is obvious. Secondly, literature addressing the topic of geriatric oncology is limited. What does exist tends to have a global focus and to be empirically based. Scientific data regarding the unique problems of the elderly is not available since age frequently excludes them from participation in clinical trials. ’ Consequently, guidelines for differentiating between the problems of aging and those that are
from Mary to modern woman: the material basis of Marianismo and its transformation in a Spanish village

In one generation, married women in an Andalusian village appeared to have turned from emulating the Virgin Mary to emulating the modern woman of Spanish advertisements and TV. Drawing on the notion that gender conceptions are aspects of cultural systems through which people negotiate relations of inequality within complex social wholes, I suggest that a concern for female chastity gave way to a concern for personal capacities and preferences when inequalities in income and life-style among villagers no longer appeared to rest on inheritance, but on the urban, salaried jobs people obtained. [Mediterranean society, gender, political economy, honor code, ideology]
The inconsistency of Physics (with a capital “P”)

This paper discusses a conception of physics as a collection of theories that, from a logical point of view, is inconsistent. It is argued that this logical conception of the relations between physical theories is too crude. Mathematical subtleties allow for a much more nuanced and sophisticated understanding of the relations between different physical theories.
Random Sequential Adsorption Model for the Differential Coverage of Gold (111) Surfaces by Two Related Silicon Phthalocyanines

We present a simple model for the discrepancy in the coverage of a gold (111) surface by two silicon phthalocyanines. The model involves random sequential adsorption (RSA) simulations with two different landing molecules, one of which is tilted relative to the substrate surface and can (under certain conditions) allow neighboring molecules to overlap. This results in a jamming limit that is near full coverage of the surface. The nonoverlapping molecules reproduce the half-monolayer jamming limit that is common in continuum RSA models with ellipsoidal landers. Additionally, the overlapping molecules exhibit orientational correlation and orientational domain formation evolving out of a purely random adsorption process.
LOSS OF FATTY-ACID DELTA(6) DESATURATING ABILITY IN HUMAN MAMMARY EPITHELIAL-CELLS THAT EXPRESS AN ACTIVATED C-HA-RAS ONCOGENE

The synthesis of essential fatty acids (EFAs) that have been shown to inhibit breast cancer cell growth in vitro and tumor growth in animals requires desaturation at C-6 of linoleic or alpha-linolenic acid. This observation, combined with reports that many tumors and tumor cell lines are deficient in Delta(6) desaturation and/or contain low levels of 6-desaturated EFAs, has led to the suggestion that loss of Delta(6) desaturating ability is relevant to the process of malignant transformation. This study was undertaken in search of direct evidence that malignant transformation of mammary epithelial cells alters EFA metabolism. We used two cell lines derived from the spontaneously immortalized human mammary epithelial cell line MCF-10A and expressing either the c-Ha-ras protooncogene (MCF-10AneoN) or an activated c-Ha-ras oncogene (MCF-10AneoT), and a cell line immortalized by transfection of human mammary epithelial cells with SV40 T antigen. We compared these cell lines in terms of ability to convert EFAs (30 mu M) to other EFAs of the same family. MCF-10AneoT cells lose the ability to perform Delta(6) and Delta(4) desaturations, whereas MCF-10AneoN cells and the SV40 T antigen-transformed cell line do not. No significant changes in growth response to culture with 6-desaturated EFAs were noted for MCF-10AneoT cells compared with MCF-10AneoN and parental MCF-10A cells, suggesting that FA metabolism alone cannot account for the effects of EFAs on the growth of neoplastic and non-neoplastic mammary epithelial cells.
The oceanic anthropogenic CO2 sink: Storage, air-sea fluxes, and transports over the industrial era

This study presents a new estimate of the oceanic anthropogenic CO2(Cant) sink over the industrial era (1780 to present), from assimilation of potential temperature, salinity, radiocarbon, and CFC-11 observations in a global steady state ocean circulation inverse model (OCIM). This study differs from previous data-based estimates of the oceanic Cant sink in that dynamical constraints on ocean circulation are accounted for, and the ocean circulation is explicitly modeled, allowing the calculation of oceanic Cant storage, air-sea fluxes, and transports in a consistent manner. The resulting uncertainty of the OCIM-estimated Cant uptake, transport, and storage is significantly smaller than the comparable uncertainty from purely data-based or model-based estimates. The OCIM-estimated oceanic Cant storage is 160–166 PgC in 2012, and the oceanic Cant uptake rate averaged over the period 2000–2010 is 2.6 PgC yr−1 or about 30% of current anthropogenic CO2 emissions. This result implies a residual (primarily terrestrial) Cant sink of about 1.6 PgC yr−1 for the same period. The Southern Ocean is the primary conduit for Cant entering the ocean, taking up about 1.1 PgC yr−1 in 2012, which represents about 40% of the contemporary oceanic Cant uptake. It is suggested that the most significant source of remaining uncertainty in the oceanic Cant sink is due to potential variability in the ocean circulation over the industrial era.
An efficient synchronization mechanism for mirrored game architectures

Existing online multiplayer games typically use a client-server model, which introduces a single bottleneck and point of failure to the game. Distributed multiplayer games remove the bottleneck, but require special synchronization mechanisms to provide a consistent game for all players. Current synchronization methods have been borrowed from distributed military simulations and are not optimized for the requirements of fast-paced multiplayer games. In this paper we present a new synchronization mechanism, trailing state synchronization (TSS), which is designed around the requirements of distributed first-person shooter games.We look at TSS in the environment of a mirrored game architecture, which is a hybrid between traditional centralized architectures and the more scalable peer-to-peer architectures. Mirrored architectures allow for improved performance compared to client-server architectures while at the same time allowing for a greater degree of centralized administration than peer-to-peer architectures.
Beyond the manual: The insider's guide to Prolonged Exposure therapy for PTSD

Prolonged Exposure therapy (PE; Foa & Rothbaum, 1998) has strong empirical support for its efficacy in reducing trauma-related psychopathology in individuals with chronic PTSD (Rothbaum, Meadows, Resick, & Foy, 2000) . In the process of providing PE to many clients and in training therapists in a variety of settings in its use, we at the Center for the Treatment and Study of Anxiety have amassed extensive experience with this therapy. This article extends the treatment guidelines provided in the PE treatment manual by sharing the knowledge and wisdom that years of experience have brought us. We emphasize the importance of forging a strong therapeutic alliance and providing a thorough rationale for treatment, discuss ways to implement in-vivo and imaginal exposure so as to promote effective emotional engagement with traumatic memories, and conclude with some recommendations for how therapists who conduct PE for PTSD can take care of themselves while delivering a therapy that is very rewarding and, at times, emotionally challenging.
Creating Professional Identity: Dilemmas and Metaphors of a First-Year Chemistry Teacher.

Through a hermeneutic phenomenological research perspective, the teaching journal of a first year chemistry teacher was examined to address the question: What is the nature of creating a professional identity of science teacher? We describe three dilemmas the teacher experienced, the metaphors she created, and the identity she constructed. The three dilemmas included: feeling like a student versus the expectation to act like an adult; wanting to care for students versus the expectation to be tough; and feeling incompetent in knowledge of chemistry versus the expectation to be an expert. As each dilemma was addressed, the teacher created a metaphor that integrated the teacher she wanted to be and the job she thought others expected her to do. Metaphors provided images that integrated her personal identity with her emerging professional identity. Implications for teacher education are discussed. © 1998 John Wiley & Sons, Inc. Sci Ed82:293–310, 1998.
The Legacy of Mystery Science Theater 3000: Text, Textual Production, Paracinema, and Media Literacy

Abstract Paracinema, as proposed by Jeffrey Sconce, an activity in which audiences seek out marginalized films and both celebrate and ridicule them (535), is a practice that offers lessons in media literacy and textual production. Mystery Science Theater 3000 (MST3K) is an important cultural artifact that offers these lessons to mainstream audiences. Using Brian Ott's theory of textual production, and Ott and Cameron Walter's theory of intertextuality as textual strategies, this article demonstrates MST3K is an enactment of paracinematic practice. MST3K is a text that teaches paracinema's media literacy, particularly in a world where interactivity is conflated with a truly active audience.
Amplitude changes in components of the auditory evoked potentials during a reward-associated counting task

Auditory evoked potentials (AEPs) were recorded while subjects were instructed to count each of a series of clicks as they were presented via earphones. Reward was made available following a response after the 20th click. AEPs to these clicks were computed separately for five successive time windows during these series. Four waves of the AEP were examined for systematic change in amplitude. The earliest wave (N92) did not change, but the following three waves (P171, N240, and P339) showed gradual increasing amplitudes as the reward approached. However, more complex changes, such as a sudden postreward decrement or prereward enhancement, which are often associated with the fixed-interval reinforcement schedules, were not clearly observable.
AGRIN FUNCTION ASSOCIATED WITH OCULAR DEVELOPMENT IS A TARGET OF ETHANOL EXPOSURE IN EMBRYONIC ZEBRAFISH

BACKGROUND Alcohol (ethanol) is a teratogen known to affect the developing eyes, face and brain. Among the ocular defects in fetal alcohol spectrum disorder (FASD) are microphthalmia and optic nerve hypoplasia. Employing zebrafish as an FASD model provides an excellent system to analyze the molecular basis of prenatal ethanol exposure-induced defects since embryos can be exposed to ethanol at defined developmental stages and affected genetic pathways can be examined. We have previously shown that disruption of agrin function in zebrafish embryos produces microphthalmia and optic nerve hypoplasia.
Regional Management of Liver Metastases. II

Introduction To Part I This is the first of a two part series. In this issue, Part I presents the natural history of liver metastasis and various proposed staging systems. Indications for surgical resection, which remains the treatment of choice are reviewed. For the majority of patients with unresectable metastases of the liver, various regional treatment approaches seem to give higher response rates than systemic chemotherapy. Technical aspects and therapeutic results of infusion chemotherapy via the hepatic artery and ligation of hepatic artery alone are considered. The totally implantable pump represents an advance in long-term infusion chemotherapy.
Generation of electromagnetic ion cyclotron waves in the ionosphere by localized transverse dc electric fields

[1] Localized dc electric fields directed perpendicular to the geomagnetic field are studied as a possible ionospheric source of electromagnetic ion cyclotron waves. The eigenvalue formulation of the problem is solved numerically and a class of unstable electromagnetic ion cyclotron eigenmodes are found that have properties consistent with some observations of broadband waves near auroral arcs. The frequency range of instability is comparable to the spectral width measured from photometer observations of broadband auroral flickering. Eigenmodes are associated with electric field polarization reversals and E/B ratios similar to that encountered by satellites and sounding rockets traversing auroral arcs. The dc electric field affects ion resonance conditions and allows for resonant interaction within the extent of the eigenfunction.
The ectodomain of Toll-like receptor 9 is cleaved to generate a functional receptor

Mammalian Toll-like receptors (TLRs) 3, 7, 8 and 9 initiate immune responses to infection by recognizing microbial nucleic acids; however, these responses come at the cost of potential autoimmunity owing to inappropriate recognition of self nucleic acids. The localization of TLR9 and TLR7 to intracellular compartments seems to have a role in facilitating responses to viral nucleic acids while maintaining tolerance to self nucleic acids, yet the cell biology regulating the transport and localization of these receptors remains poorly understood. Here we define the route by which TLR9 and TLR7 exit the endoplasmic reticulum and travel to endolysosomes in mouse macrophages and dendritic cells. The ectodomains of TLR9 and TLR7 are cleaved in the endolysosome, such that no full-length protein is detectable in the compartment where ligand is recognized. Notably, although both the full-length and cleaved forms of TLR9 are capable of binding ligand, only the processed form recruits MyD88 on activation, indicating that this truncated receptor, rather than the full-length form, is functional. Furthermore, conditions that prevent receptor proteolysis, including forced TLR9 surface localization, render the receptor non-functional. We propose that ectodomain cleavage represents a strategy to restrict receptor activation to endolysosomal compartments and prevent TLRs from responding to self nucleic acids.
SU‐FF‐T‐290: Impact of MLC Modeling and Sensitivity of Its Parameters On Monte Carlo Simulation of IMRT

Purpose:Monte Carlo simulation(MCS) offers the most sophisticated dose calculation for IMRT with complex delivery systems using MLCs. The purposes of this work are to determine: (1) to what degree of accuracy and complexity MLCs have to be modeled in MCS; (2) what are the most sensitive tests and effective ways of determining free parameters for MCS‐IMRT, including leaf density, leaf geometry, and incident electron beamsource size. Method and Materials: A generic MLC model was developed for BEAMnrc system. This model described MLCs based on matrices of regions, each of which can be independently defined for its material and geometry, allowing maximum flexibility of simulating MLCs for various manufacturers. To commission the MLC model for Varian Millenium MLC, we measured transmission ratios and intensity maps for various leaf patterns designed to magnify the effects of leaf transmission, leakage, and tongue‐and‐groove. In addition, TLDmeasurements were also taken for clinical IMRT plans using anthropomorphic phantoms. Several parameter sets of leaf density, leaf geometry, and electron source size were tested to evaluate dosimetric effects of these parameters and to determine the optimal combination. Results: The overall‐transmission ratios were strongly dependent on both leaf density and inter‐leaf air gap. Meanwhile, electron source size had less effect on transmission and leakage. Inter‐leaf air gap and tongue‐and‐groove geometry can be determined most effectively through fence‐type MLC patterns. The optimal parameter range was 17.35–17.70g/cm3 for leaf density, 0.08–0.11mm for inter‐leaf air gap with detailed tongue‐and‐groove modeling, and 0.1–0.2cm for electron source size. With these parameters, MCS calculated and measuredTLD dose showed clinical‐acceptable agreement from low to high dose regions. Conclusion:MLC modeling critically affected the accuracy of MCS for IMRT. The free parameters for the MLC have to be carefully determined by separate measurements for MCS.
Observability for optimal sensor locations in data assimilation

In this paper we will discuss the application of observability to the planning of sensor configurations in numerical weather prediction (NWP). The dimensions used in NWP make conventional definitions of observability impractical. For this reason we will rely partial observability which is obtained using dynamic optimization to approximate the observability. Using this metric we will form an optimization problem to select sensor configurations that maximize the partial observability of the dynamical system. This leads to a max–min problem which using an empirical gramian matrix we reduce to an eigenvalue optimization problem. Atmospheric data assimilation is the process of combining prior knowledge with observations to form an estimate of the system state required to produce a forecast of future weather conditions. Optimal sensor configurations leading to improved forecast quality are of interest. Due to the potential size of our intended application we will focus on computational methods that are both efficient and scalable. We will also leverage existing tools used in data assimilation and introduce tools used in nonsmooth optimization.
Effect of Gibberellic Acid on Flower Differentiation in Petkus Winter Rye

IT is known that application of gibberellic acid causes flowering of many biennials (Hyoscyamus, Apium, Brassica, Daucus, etc.)1. In these cases gibberellic acid substitutes for cold (vernalization) treatment. Treatment of winter cereals (Petkus rye2, barley3, winter wheat4) with gibberellic acid, on the contrary, has been found to have no effect on the induction of normal flowers. Chaylakhian5 has reported that treatment of non-vernalized oats, variety Victory, with gibberellic acid, under short-day conditions, caused formation of an increased number of developed panicles. This was not the case under long-day conditions. Paleg and Aspinall3 have reported that treatment of barley with gibberellic acid for several weeks immediately following emergence results in the formation of abnormal spikes.
The integration of coastal zone management into national development planning

The broad acceptance and collective commitment of countries to the tasks involved in the implementation of Agenda 21, Chapter 17, have profound implications vis-a-vis the interplay between coastal zone management (CZM) and national development planning (NDP). It appears that in many countries, CZM has evolved in isolation from the mainstream of national development processes. The paper examines various forms and elements for the effective integration of CZM into NDP.
Genetic modeling of gliomas in mice: new tools to tackle old problems

The recently published comprehensive profiles of genomic alterations in glioma have led to a refinement in our understanding of the molecular events that underlie this cancer. Using state-of-the-art genomic tools, several laboratories have created and characterized accurate genetically engineered mouse models of glioma based on specific genetic alterations observed in human tumors. These in vivo brain tumor models faithfully recapitulate the histopathology, etiology, and biology of gliomas and provide an exceptional experimental system to discover novel therapeutic targets and test therapeutic agents. This review focuses on mouse models of glioma with a special emphasis on genetically engineered models developed around key genetic glioma signature mutations in the PDGFR, EGFR, and NF1 genes and pathways. The resulting animal models have provided insight into many fundamental and mechanistic facets of tumor initiation, maintenance and resistance to therapeutic intervention and will continue to do so in the future.
Experiments on the Noise Produced by High Speed Jets with Elliptic Exhaust Nozzles

Experiments have been carried out to investigate the potential for noise reductions on low bypass ratio turbofan engines with minimal impact on performance. This design exploits the directional characteristics of the jet noise radiated by elliptic nozzles. Experiments were conducted on elliptic jets with a variety of aspect ratios in the Penn State anechoic chamber jet noise facility. Heated jets are accurately simulated using precise mixtures of helium and air in the jet supply gas. The jet operating conditions range from Mach number 0.5 to 1.2 and the jet temperature ranges from unheated (cold) to hot jets with simulated static temperature ratios as high as 2.8. Additional acoustic measurements were performed with a small-scale turbojet engine. The elliptically shaped jet causes the turbulent shear layer surrounding the high-speed jet to merge at a shorter distance downstream of the nozzle exit. Upon merging, the centerline velocity decays sooner, and the average velocity of the jet decays at a shorter distance downstream. With a shorter length of high velocity turbulence components, the total generated noise can be decreased in the major axis plane of the jet. However, this is not at the expense of an increase in the high frequency contributions to the radiated noise spectrum. For supersonic hot jets, the overall sound pressure level is reduced by about 3 dB in the maximum noise reduction direction, as compared to a round nozzle creating a jet with the same exit conditions. It appears that for reasons we do not fully understand, noise reductions are not achieved with unheated high speed elliptic jets over the parameter range most commonly used. Moreover, subsonic jets with elliptic nozzles produce no noise reduction advantage. As part of the study, a comprehensive method of separating the jet noise from the engine core noise, from acoustic measurements alone, is summarized.
LP-D: Late-News Poster: High-Efficiency LCD Projection Displays with Novel Thin-Film Polarizing Beam Splitters

Abstract A novel high performance thin film polarizing beam-splitter (PBS) has been invented and demonstrated. ThisPBS is non-absorbing and has a broadband, wide angularfield and high extinction ratios for both reflected and trans-mitted beams. Significant brightness enhancement is ob-served in two prototype high efficiency LCD projectiondisplays based on this PBS. 1. Objective and BackgroundThe objective of this research is to develop a novel highperformance polarizing beam-splitter and to demonstrate theprinciple of high efficiency projection displays based on thisnovel PBS.Currently, most liquid crystal displays (LCDS) are basedon twisted nematic liquid crystals that require the use of twopolarizers. A typical TN LC pixel consists of a liquid crystallayer and two transparent electrodes. The pixel is sandwichedbetween the first polarizer and the second polarizer. Thetransmitting axes of the two polarizers are either perpendicu-lar (normally white) or parallel (normally black) to eachother. Un-polarized incident light passes through the firstpolarizer and becomes linearly polarized. When no voltage isapplied to the liquid crystal layer, it acts as a halfwave plateand rotates the polarization of the incident polarized light by90°, The light will therefore be transmitted by the secondpolarizer (in the perpendicular case) and the pixel is in an“on” state. When a voltage is applied to a liquid crystal pixel,the liquid crystal molecules align themselves with the electricfield and the light does not undergo rotation in the plane ofpolarization. In this instance, the light is blocked by thesecond polarizer and the pixel is in an “off” state.Plastic sheet polarizers are currently the only choice forboth flat panel and projection LCD displays because of theirbroad bandwidth and wide angular field. However, thesesheet polarizers absorb light of one polarization in order toobtain polarized light of another polarization. This absorp-tion causes two problems:1. More than 50% of the incident light is absorbed by thefirst polarizer and this makes the display less energy ef-ficient. For example, the total light output from a direct-view LCD panel is only about
Comprehensive human genetic maps: individual and sex-specific variation in recombination.

Comprehensive human genetic maps were constructed on the basis of nearly 1 million genotypes from eight CEPH families; they incorporated >8,000 short tandem-repeat polymorphisms (STRPs), primarily from Genethon, the Cooperative Human Linkage Center, the Utah Marker Development Group, and the Marshfield Medical Research Foundation. As part of the map building process, 0.08% of the genotypes that resulted in tight double recombinants and that largely, if not entirely, represent genotyping errors, mutations, or gene-conversion events were removed. The total female, male, and sex-averaged lengths of the final maps were 44, 27, and 35 morgans, respectively. Numerous (267) sets of STRPs were identified that represented the exact same loci yet were developed independently and had different primer pairs. The distributions of the total number of recombination events per gamete, among the eight mothers of the CEPH families, were significantly different, and this variation was not due to maternal age. The female:male ratio of genetic distance varied across individual chromosomes in a remarkably consistent fashion, with peaks at the centromeres of all metacentric chromosomes. The new linkage maps plus much additional information, including a query system for use in the construction of reliably ordered maps for selected subsets of markers, are available from the Marshfield Website.
Embracing Diversity in the Science Classroom

As each school year starts, teachers are faced with teaching and building relationships with students from diverse backgrounds. To effectively teach students, science teachers (and teachers in gene...
Room-Temperature Chemiresistive Effect of ${\rm TiO}_{2}\!-\!{\rm B}$ Nanowires to Nitroaromatic and Nitroamine Explosives

Semiconducting TiO2-B nanowires were synthesized and their chemical sensor performance was studied. It was found that the TiO2-B nanowires exhibited a large and reversible change in electrical resistivity when exposed to trace vapor of nitroaromatic and nitroamine explosives. The sensor showed high sensitivity and fast response at room temperature. The chemiresistive effect was attributed to the adsorption of high electronegativity explosives on the TiO2-B nanowires and a consequent depletion of charge carriers in the nanowires by surface states created by the explosive molecules. The role of the TiO2-B nanowires is proposed to impart both an extremely large surface area for the adsorption of gas molecules and a surface enriched in hydroxyl groups which connect to nitro groups of the explosive molecules. Chemiresistive sensors made of TiO2-B semiconducting nanowires promised to achieve micro-sized devices with several orders of magnitude reduction in dimensions, weight, and power consumption over current explosive detectors.
Designing and deploying a building-wide cognitive radio network testbed

Wireless communication technology is constantly advancing with the primary objective being to improve the quality of service for the end user. Cognitive radio is a technology capable of advancing wireless communications to the next generation of intelligent devices. Integrating cognition into wireless applications such as dynamic spectrum access, radio resource management, wireless distributed computing, and even traditional protocol stacks has already been shown to provide benefits related to the communications quality of service. The majority of cognitive radio related research has been limited to theoretical frameworks and simulations or in a few cases, demonstrating prototype DSA devices on a small scale. In order to continue advancing in this area, larger-scale experiments that are reproducible and able to be moved beyond theoretical simulations are required. Virginia Tech has built a testbed for software-defined and cognitive radio related research for the purpose of rapid next-generation communication system prototyping using a medium scale size network of flexible wireless nodes. In this article we present the details of the development, design decision rationale, and deployment of this testbed in hopes that it will be both used by the research community, and duplicated and improved in order to further the development of the many different facets of cognitive radio research.
FDG PET imaging of childhood sarcomas.

Background Positron-emission tomography (PET) imaging using [18F]fluorodeoxyglucose (FDG) is useful for detection, staging, and monitoring a variety of malignancies, including lymphoma, in adults, but its utility in sarcomas, especially soft tissue sarcomas (STS), in children and young adults is not clear. Procedure To evaluate the potential utility of FDG PET in the care of STS in children and young adults, we analyzed 46 PET scans in 25 patients acquired over 12 years. Scans were interpreted by two imaging physicians blinded to findings from other imaging studies and clinical information. Results were compared with computed tomography and magnetic resonance imaging, biopsy results, where available, and clinical follow-up of at least 12 months. Results For a total of 46 scans in 25 patients, there were 25 true-positive scans, 3 false-positive scans, 12 true-negative scans, and 6 false-negative scans. The sensitivity of the PET scan was 86%, specificity was 80%, positive predictive value was 89%, and negative predictive value was 67%. Conclusion FDG PET may be a useful imaging modality in the management of children and young adults with STS, although prospective studies are needed to establish its true utility. Pediatr Blood Cancer 2010;54:222–227. © 2009 Wiley-Liss, Inc.
O6-methylguanine-DNA methyltransferase, O6-benzylguanine, and resistance to clinical alkylators in pediatric primary brain tumor cell lines.

Purpose: Primary brain tumors are the leading cause of cancer death in children. Our purpose is (a) to assess the contribution of the DNA repair protein O 6 -methylguanine-DNA methyltransferase (MGMT) to the resistance of pediatric brain tumor cell lines to clinical alkylating agents and (b) to evaluate variables for maximal potentiation of cell killing by the MGMT inhibitor O 6 -benzylguanine, currently in clinical trials. Few such data for pediatric glioma lines, particularly those from low-grade tumors, are currently available. Experimental design: We used clonogenic assays of proliferative survival to quantitate cytoxicity of the chloroethylating agent 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and the methylating agent temozolomide in 11 glioma and five medulloblastoma lines. Twelve lines are newly established and characterized here, nine of them from low-grade gliomas including pilocytic astrocytomas. Results: (a) MGMT is a major determinant of BCNU resistance and the predominant determinant of temozolomide resistance in both our glioma and medulloblastoma lines. On average, O 6 -benzylguanine reduced LD 10 for BCNU and temozolomide, 2.6- and 26-fold, respectively, in 15 MGMT-expressing lines. (b) O 6 -Benzylguanine reduced D T (the threshold dose for killing) for BCNU and temozolomide, 3.3- and 138-fold, respectively. D T was decreased from levels higher than, to levels below, clinically achievable plasma doses for both alkylators. (c) Maximal potentiation by O 6 -benzylguanine required complete and prolonged suppression of MGMT. Conclusions: Our results support the use of O 6 -benzylguanine to achieve full benefit of alkylating agents, particularly temozolomide, in the chemotherapy of pediatric brain tumors.
Efficiency and optimization of explicit and implicit communication schemes in collaborative robotics experiments

This paper presents an investigation of three communication schemes which may be used in a distributed robotic system, two based on implicit forms of communication (mechanical interaction and vision) and one on an explicit form of communication (infrared signaling). To support the discussion, we have chosen a concrete case study concerned with locating and pulling sticks out of an arena floor, a task successfully achieved only through collaboration between two robots. Communication schemes, among other system features, heavily influence the rate of successful collaborations, the metric adopted to evaluate the performance of the robotic team. Results collected using an embodied simulator show that, as a function of the system constraints (e.g., number of robots, hardware and behavioral parameters,) solutions based on more complex individuals do not necessarily lead to an improved team performance. Although the stick pulling is a simple case study without any practical application, it presents all the main difficulties of designing and controlling scalable, distributed robotic systems, characterized by subtle, nested effects between individual and group behavior or hardware and software parameters. We believe that embodied simulations are a key level of implementation in helping us understand these subtle mechanisms, achieve further abstraction, and optimize the system before any real hardware solution is implemented.
Fine-scale genetic population structure of an understory rainforest bird in Costa Rica

We studied five populations of a rainforest understory insectivorous bird (Myrmeciza exsul, chestnut-backed antbird) in a fragmented landscape in northeastern Costa Rica in order to test hypotheses about the influence of forest fragmentation on population genetic structure using 16 microsatellite loci. Bayesian assignment approaches—perhaps the most conservative analyses we performed—consistently grouped the sites into two distinct groups, with all individuals from the smallest and most isolated population clustering separately from the other four sites. Additional analyses revealed (1) overall significant genetic structure; (2) a pattern of population differentiation consistent with a hypothesis of isolation by resistance (landscape connectivity), but not distance; and (3) relatively short dispersal distances indicated by elevated mean pairwise relatedness in several of the sites. Our results are somewhat surprising given the small geographic distances between sites (11–34 km) and the short time (~60 years) since wide-spread deforestation in this landscape. We suspect fine-scale genetic structure may occur in many resident tropical bird species, and in the case of the chestnut-backed antbird it appears that anthropogenic habitat fragmentation has important population genetic implications. It appears that chestnut-backed antbirds may persist in fragmented landscapes in the absence of significant migration among patches, but mechanisms that allow this species to persist when many other similar species do not are not well understood.
Genetics in geographically structured populations: defining, estimating and interpreting FST

FST describes the processes that lead to genetic differentiation among and within populations and is widely used in population and evolutionary genetics. This article describes the meaning of FST and how it should be estimated and interpreted.
Stem cell-like glioma cells promote tumor angiogenesis through vascular endothelial growth factor

Malignant gliomas are highly lethal cancers dependent on angiogenesis. Critical tumor subpopulations within gliomas share characteristics with neural stem cells. We examined the potential of stem cell-like glioma cells (SCLGC) to support tumor angiogenesis. SCLGC isolated from human glioblastoma biopsy specimens and xenografts potently generated tumors when implanted into the brains of immunocompromised mice, whereas non-SCLGC tumor cells isolated from only a few tumors formed secondary tumors when xenotransplanted. Tumors derived from SCLGC were morphologically distinguishable from non-SCLGC tumor populations by widespread tumor angiogenesis, necrosis, and hemorrhage. To determine a potential molecular mechanism for SCLGC in angiogenesis, we measured the expression of a panel of angiogenic factors secreted by SCLGC. In comparison with matched non-SCLGC populations, SCLGC consistently secreted markedly elevated levels of vascular endothelial growth factor (VEGF), which were further induced by hypoxia. In an in vitro model of angiogenesis, SCLGC-conditioned medium significantly increased endothelial cell migration and tube formation compared with non-SCLGC tumor cell-conditioned medium. The proangiogenic effects of glioma SCLGC on endothelial cells were specifically abolished by the anti-VEGF neutralizing antibody bevacizumab, which is in clinical use for cancer therapy. Furthermore, bevacizumab displayed potent antiangiogenic efficacy in vivo and suppressed growth of xenografts derived from SCLGC but limited efficacy against xenografts derived from a matched non-SCLGC population. Together these data indicate that stem cell-like tumor cells can be a crucial source of key angiogenic factors in cancers and that targeting proangiogenic factors from stem cell-like tumor populations may be critical for patient therapy.
Sleeve gastrectomy induces loss of weight and fat mass in obese rats, but does not affect leptin sensitivity.

Background & Aims Surgical intervention produces sustainable weight loss and metabolic improvement in obese individuals. Vertical sleeve gastrectomy (VSG) produces dramatic, sustained weight loss; we investigated whether these changes result from improved sensitivity to leptin. Methods VSG was performed in Long–Evans rats with diet-induced obesity. Naive or sham-operated rats, fed either ad libitum or pair-fed with the VSG group, were used as controls. Following surgery, body weights and food intake were monitored. We investigated energy expenditure, meal patterns, leptin sensitivity, and expression of pro-opiomelanocortin/agouti-related peptide/neuropeptide Y in the hypothalamus of the rats. Results We observed sustained losses in weight and body fat in male and female rats after VSG. Weight loss persisted after the disappearance of a transient, postsurgical food intake reduction. Resting energy expenditure was similar between control and VSG rats. VSG rats maintained their reduced body weights. However, they responded to a chronic food restriction challenge by overeating, which resulted in prerestriction, rather than pre-VSG, body weights. Consistent with lower adiposity, VSG decreased plasma leptin levels. Although VSG slightly improved leptin's anorectic action, the response was comparable to that observed in controls matched for adiposity by caloric restriction. Changes in hypothalamic neuropeptide expression were consistent with the lower body weight and lower leptin levels but cannot account for the sustained weight loss. Conclusions VSG causes sustained reduction in body weight, which results from loss of fat mass. The maintenance of weight loss observed did not result from changes in sensitivity to leptin.
Methodology to qualify silicon carbide MOSFETs for single shot avalanche events

This paper presents a methodology to establish and qualify safe bounds of operation for Silicon Carbide power devices under avalanche stress. The methodology involves using a statistical method to estimate an avalanche safe operating area, and by ensuring that device reliability is not degraded after avalanche stress. We also demonstrate the avalanche capability of the C3M 900V SiC MOSFETs, which have been fully qualified for avalanche ruggedness by employing this methodology.