cssi/SciSciGPT-SciSciNet huggingface dataset:
An in vivo and in vitro autoradiographic investigation of growth in synchondrosal cartilage.

The inherent growth potential of synchondrosal cartilage has been studied as follows. Sixty CD-1 mice were injected with 3H-thymidine on their first day of life. Thirty of these were sacrificed one hour after injection, and their cranial bases were removed and placed in an organ culture system. The explants were removed from culture at six-hour intervals for one day and then every 24 hours for five more days. The remaining animals, which comprise the in vivo series, were sacrificed by decapitation at corresponding times. In order to detect cell movements, the spheno-occipital synchondroses were divided into five zones, and labeled cell counts were done for each zone. The labeled cartilage cells spread apart with growth as new cells were formed in the central zone and moved toward the outer zones The labeled cells moving from the central resting zone to the outer hypertrophic zones were comparable in absolute number and in rate of movement in both the in vivo and in vitro cartilages. The fact that synchondroses grown in culture retained their capacity for growth without benefit of neighboring tissues seems to indicate that the spheno-occipital synchondrosis possesses an inherent potential for growth and is not merely reactive or adaptive in nature.
High-beta injection experiments on the ISX-B tokamak

Neutral-beam injection of up to 2.5 MW into plasmas in the ISX-B tokamak (R0 = 0.93 m, a = 0.27 m, BT = 0.9–1.5 T, Ip = 70–210 kA, e = 2.5–10×1013 cm−3) has created plasmas with volume-averaged beta of up to ~ 2.5%, peak beta values of up to ~ 9%, and root-mean-square beta values of up to ~ 3.5%. Energy confinement time is observed to decrease by about a factor of two as beam power goes from 0 to 2.5 MW; the decrease is caused predominantly by the electron confinement time falling below the predictions of 'Alcator scaling' by a factor of 3–4 at high beam power. An empirical relationship of the form fits our measurements over a wide range of plasma parameters. The function f(Pb), where Pb is the beam power, is linear for Pb ≤ 1.2 MW but tends to saturate for 1.2 MW ≤ Pb ≤ 2.5 MW. Although the equilibria attained in ISX-B are predicted to be above the threshold for the ideal magnetohydrodynamic (MHD) ballooning instability, no evidence of these modes is observed.
Evolution of insulin-like growth factor I (IGF-I): structure and expression of an IGF-I precursor from Xenopus laevis.

By means of a cloning strategy employing the polymerase chain reaction, we have isolated and characterized cDNAs for Xenopus laevis insulin-like growth factor I (IGF-I). These cDNAs encode a primary IGFI translation product of 153 residues that demonstrates considerable amino acid sequence similarity with IGF-IA peptides from other species. Fifty-seven of 70 residues of the mature protein are identical among human, rat, chicken, and Xenopus IGF-I, while less amino acid conservation is found at the COOH-terminus (25/35 identities) or at the NH2-terminus (24/48 identities) of the precursor protein. Despite the lower degree of structural similarity at the NH2-terminus, in vitro studies of IGF-I biosynthesis and proteolytic processing support a conserved function for the atypically long 48 residue NH2-terminal signal sequence in directing the nascent IGF-I peptide through the secretory pathway. The 5′-untranslated region of Xenopus IGF-I mRNA matches the human, rat, and chicken sequences in greater than 90% o...
Moments of spherically symmetric kernels for multivariate local regression and density estimation

We find a general formula for moments of spherically symmetric multivariate kernels, and provide details for kernels in common use.
Amino acid uptake in deciduous and coniferous taiga ecosystems

We measured in situ uptake of amino acids and ammonium across deciduous and coniferous taiga forest ecosystems in interior Alaska to examine the idea that late successional (coniferous) forests rely more heavily on dissolved organic nitrogen (DON), than do early successional (deciduous) ecosystems. We traced 15N-NH 4 + and 13C-15N-amino acids from the soil solution into plant roots and soil pools over a 24 h period in stands of early successional willow and late successional black spruce. Late successional soils have much higher concentrations of amino acid in soil solution and a greater ratio of DON to dissolved inorganic N (DIN) (ammonium plus nitrate) than do early successional soils. Moreover, late successional coniferous forests exhibit higher rates of soil proteolytic activity, but lower rates of inorganic N turnover. Differences in ammonium and amino acid uptake by early successional willow stands were insignificant. By contrast, the in situ uptake of amino acid by late successional black spruce forests were approximately 4-fold greater than ammonium uptake. The relative difference in uptake of ammonium and amino acids in these forests was approximately proportional to the relative difference of these N forms in the soil solution. Thus, we suggest that differences in uptake of different N forms across succession in these boreal forests largely reflect edaphic variation in available soil N (composition), rather than any apparent physiological specialization to absorb particular forms of N. These finding are relevant to our understanding of how taiga ecosystems may respond to increases in temperature, fire frequency, N deposition, and other potential consequences of global change.
A study of the (00) LEED beam intensity at normal incidence from CdS(0001), Cu(001), Cu(111), and Ni(111)

A Faraday cage apparatus is used for the measurement of the (00) LEED beam intensity, I(00), and the total secondary emission coefficient, δ(Ek), for angles of incidence from 0° ± 2° to 8° ± 2°, with an energy resolution of ± 0.037 of the incident beam energy, in the energy range 1 to 200 eV. The data are normalized and expressed as a fraction of the incident beam intensity. The basic principle of operation is the separation of the incident and specularly diffracted beams in a uniform magnetic field. Monolayer, or in-plane, resonances associated with the emergence of nonspecular beams, as well as beam threshold minima, are observed in I(00) at normal incidence from clean CdS(0001), Cu(111), and Ni(111). Some major differences are observed in the I(00) profiles for the clean (111) surfaces of nickel and copper. All secondary Bragg peaks, except the 223 order, have greater intensities for Ni(111) in the energy range 50–150 eV, thus indicating that the atomic scattering cross-section for electrons in this energy range is larger for nickel than for copper. For the (111) surface of nickel, the (11) resonance is missing, but the (10) resonance and all 13 order secondary Bragg peaks between the second and fifth orders are observed. For Cu(111) both the (10) and (11) resonances are observed, but the 13, 23, 123, and 313 order secondary Bragg peaks are missing in this energy range. These data indicate that multiple scattering with evanescent intermediate waves, or “shadowing”, is predominate on the (111) surfaces on nickel and copper for energies above 30 eV, and that below 30 eV multiple scattering with propagating intermediate waves is predominate on Cu(111). Correlation of the (00) beam intensity profiles from clean Ni(111) at 0°, 2°, and 6° with the intensity profiles of the (10). (10), and (11) non-specular beams is nearly one-to-one from 30 eV to 100 eV, thus supporting the dynamical theories of LEED in which peaks in the (00) beam are expected to occur at nearly the same energies as peaks in the non-specular beams.
Formation of hexavalent chromium by reaction between slag and magnesite-chrome refractory

The goal of this work was to understand how Cr6+ formation is affected by the interaction between chromite phases present in magnesite-chrome refractory and different slag compositions. In addition, the formation of Cr6+ as a function of chromite particle size and cooling rate due to the chromite phase/slag interaction was investigated. The following slag compositions were studied: calcium aluminate, calcium aluminum silicate, and calcium silicate. It was found that the presence of uncombined CaO in the calcium aluminate slags is responsible for a higher yield of Cr6+. However, the replacement of Al2O3 by SiO2 in calcium aluminate slags decreases the formation of Cr6+. SiO2 reacts with CaO to form stable 2CaO·Al2O3·SiO2 and CaO·SiO2 phases, consequently decreasing the amount of uncombined CaO available to react with the chromite phase to form Cr6+. Moreover, the content of Cr6+ is decreased by increasing chromite particle size and increasing the cooling rate of magnesite-chrome refractory.
Population movement in Zhejiang province, China: the impact of government policies.

"China's urbanization policies include strict control of permanent migration to large cities, but encourage the growth of small cities and towns. Concurrently, temporary migration is widely permitted as a way to stimulate commerce. Data for Zhejiang province indicate that permanent mobility is largely directed toward urban places, that towns gain more than cities and that rural areas experience migration losses. Permanent migrants to urban places are selective of the better educated. Temporary migration is also urban directed but greater in volume than permanent migration, and places considerable strain on urban infrastructure. Government policies are a key to understanding the migration streams and migrant characteristics. The considerable net movement into cities suggests that strict control of city growth is more difficult to achieve than envisaged by policymakers." This is a revised version of a paper originally presented at the 1989 Annual Meeting of the Population Association of America (see Population Index, Vol. 55, No. 3, Fall 1989, p. 386).
Do Oligodendrocytes Divide

Remyelination occurs in the adult central nervous system following a wide variety of experimental and naturally occurring demyelinating conditions, including multiple sclerosis. Remyelination is preceded by the appearance of new oligodendrocytes. These new cells may be generated from glial precursor cells, or from pre-existing differentiated oligodendrocytes that re-enter the cell cycle, which may first dedifferentiate, or both processes may occur. The evidence for the source of new oligodendrocytes following toxic or immune-mediated lesions is reviewed. Good evidence exists that fully differentiated oligodendrocytes can incorporate [3H]thymidine but this may be a rare event. Most of the evidence points towards glial precursor cells as the source of new oligodendrocytes in the adult, but definitive experiments have not yet been done. Research strategies, using our current knowledge and techniques, are outlined for solving this problem.
A Novel Pump for MEMS Applications

Department of Aerospace and Mechanical EngineeringUniversity of Notre DameNotre Dame, IN 46556We present a novel approach for pumping fluids in micromechanical applications atextremely low Reynolds numbers. It is based on the rotation of a cylinder placed asymmetricallyin a narrow duct; the differential viscous resistance between the small and large gaps causes a netflow along the channel. We report on experiments using glycerin and several cm-scale prismshaving circular, square and rectangular cross-sections. The Reynolds number, based on cylindersize and angular velocity, varies in the range of 0.01–10. The flow is visualized using tracerparticles. The flow generated depends on the geometrical parameters, but is proportional to theangular velocity of the cylinder. An average flow velocity that is about 10% of the surface speedof the cylinder has been obtained.Manufacturing processes that can create extremely small machines have been developed inrecent years. Motors, electrostatic actuators, pneumatic actuators, valves, gears and tweezers ofabout 10 µm size have been fabricated. These have been used as sensors for pressure,temperature, velocity, mass flow, or sound, and as actuators for linear and angular motions.Current usage ranges from airbags to blood analysis (O'Connor, 1992). There is considerablework under way to include other applications, one example being the micro-steam engine describedby Lipkin (1993). Many of these new applications will need fluid to be pumped in a duct; at suchsmall scales this is a challenge.There have been several studies of microfabricated pumps. Some of them use non-mechanical effects. Ion-drag is used in electrohydrodynamic pumps (Bart et al., 1990; Richter et
What is this thing called frequency

When researchers are interested in the influence of long-term knowledge on performance, printed word frequency is typically the variable of choice. Despite this preference, we know little about what frequency norms measure. They ostensibly index how often and how recently words are experienced, but words appear in context, so frequency potentially reflects an influence of connections with other words. This paper presents the results of a large free association study as well as the results of experiments designed to evaluate the hypothesis that common words have stronger connectionsto other words. The norms indicate that common words tend to be more concrete but they do not appear to have more associates, stronger associates, or more connections among their associates. Two extralist cued recall experiments showed that, with other attributes being equal, high- and low-frequency words were equally effective as test cues. These results suggest that frequency does not achieve its effects because of stronger or greater numbers of connectionsto other words, as implied in SAM. Other results indicated that common words have more connectionsfrom other words, including their associates, and that free association provides a valid index of associative strength.
Two upstream enhancers collaborate to regulate the spatial patterning and timing of MyoD transcription during mouse development

MyoD is a member of the basic-helix-loop-helix (bHLH) transcription factor family, which regulates muscle determination and differentiation in vertebrates. While it is now well established that the MyoD gene is regulated by Sonic hedgehog, Wnts, and other signals, it is not known how MyoD transcription is initiated and maintained in response to these signals. We have investigated the cis control of MyoD expression to identify and characterize the DNA targets that mediate MyoD transcription in embryos. By monitoring lacZ reporter gene expression in transgenic mice, we show that regulatory information contained in 24 kb of human MyoD 5′ flanking sequence is sufficient to accurately control MyoD expression in embryos. Previous studies have identified two muscle-specific regulatory regions upstream of MyoD, a 4-kb region centered at −20 kb (designated fragment 3) that contains a highly conserved 258-bp core enhancer sequence, and a more proximal enhancer at −5 kb, termed the distal regulatory region (DRR), that heretofore has been identified only in mice. Here, we identify DRR-related sequences in humans and show that DRR function is conserved in humans and mice. In addition, transcriptional activity of MyoD 5′ flanking sequences in somites and limb buds is largely a composite of the individual specificities of the two enhancers. Deletion of fragment 3 resulted in dramatic but temporary expression defects in the hypaxial myotome and limb buds, suggesting that this regulatory region is essential for proper temporal and spatial patterning of MyoD expression. These data indicate that regulatory sequences in fragment 3 are important targets of embryonic signaling required for the initiation of MyoD expression. © 2001 Wiley-Liss, Inc.
What future for ribavirin

The optimal therapy for patients with the chronic hepatitis C virus (HCV) is a combination of peginterferon and ribavirin. Treating HCV without ribavirin or prematurely discontinuing, frequently missing doses of ribavirin is associated with a significant decline in virological response, and an increase in both breakthrough viraemia and relapse. The major limitation of ribavirin is adverse events, the most common of which is haemolytic anaemia. Haemolysis is modest when ribavirin is utilized as monotherapy, but is significantly increased when combined with interferon or peginterferon. For these reasons, attempts to replace ribavirin with a less toxic alternative have been advanced. Unfortunately, even when ribavirin is replaced by a potent protease inhibitor, relapse is significantly increased and SVR is reduced. The future of HCV treatment is to combine peginterferon and ribavirin with several protease and/or polymerase inhibitors. Whether this strategy will allow ribavirin to be removed from the treatment paradigm remains to be proven. However, based on the results of clinical trials conducted to date, it is much more likely that peginterferon, not ribavirin, could be expendable.
Parameterized memory/processor optimizing FORTRAN compiler for parallel computers

A new approach to generating low-conflict parallel instructions for complex applications is introduced in this paper. This method is presented within the context of a FORTRAN compiler. An approximate simulator has been incorporated within a parallel-code/domain-decomposition loop within the compiler. The simulator estimates the performance of candidate instruction segments, and guides the selection of appropriate code transformations, heuristics, and data storage strategies. At present, many aspects of the target machine are parameterized, to permit investigations of a number of parallel-computer architectures. In this paper, the compiler is illustrated for a Navier-Stokes computer target node application. >
Dry Cereals Fortified with Electrolytic Iron or Ferrous Fumarate Are Equally Effective in Breast-fed Infants

Precooked, instant (dry) infant cereals in the US are fortified with electrolytic iron, a source of low reactivity and suspected low bioavailability. Iron from ferrous fumarate is presumed to be more available. In this study, we compared a dry infant rice cereal (Cereal L) fortified with electrolytic iron (54.5 mg iron/100 g cereal) to a similar cereal (Cereal M) fortified with ferrous fumarate (52.2 mg Fe/100 g) for efficacy in maintaining iron status and preventing iron deficiency (ID) in breast-fed infants. Ascorbic acid was included in both cereals. In this prospective, randomized double-blind trial, exclusively breast-fed infants were enrolled at 1 mo and iron status was determined periodically. At 4 mo, 3 infants had ID anemia and were excluded. Ninety-five infants were randomized at 4 mo, and 69 (36 Cereal L, 33 Cereal M) completed the intervention at 9 mo. From 4 to 9 mo, they consumed daily one of the study cereals. With each cereal, 2 infants had mild ID, a prevalence of 4.2%, but no infant developed ID anemia. There were no differences in iron status between study groups. Iron intake from the study cereals was (mean ± SD) 1.21 ± 0.31 mg⋅kg(-1)⋅d(-1) from Cereal L and 1.07 ± 0.40 mg⋅kg(-1)⋅d(-1) from Cereal M. Eleven infants had low birth iron endowment (plasma ferritin < 55 μg/L at 2 mo) and 54% of these infants had ID with or without anemia by 4 mo. We conclude that electrolytic iron and ferrous fumarate were equally efficacious as fortificants of this infant cereal.
Comparison of a gross anatomy laboratory to online anatomy software for teaching anatomy

This study was designed to assess the grades, self-perceived learning, and satisfaction between occupational therapy students who used a gross anatomy laboratory versus online anatomy software (AnatomyTV) as tools to learn anatomy at a large public university and a satellite campus in the mid-western United States. The goal was to determine if equivalent learning outcomes could be achieved regardless of learning tool used. In addition, it was important to determine why students chose the gross anatomy laboratory over online AnatomyTV. A two group, post-test only design was used with data gathered at the end of the course. Primary outcomes were students' grades, self-perceived learning, and satisfaction. In addition, a survey was used to collect descriptive data. One cadaver prosection was available for every four students in the gross anatomy laboratory. AnatomyTV was available online through the university library. At the conclusion of the course, the gross anatomy laboratory group had significantly higher grade percentage, self-perceived learning, and satisfaction than the AnatomyTV group. However, the practical significance of the difference is debatable. The significantly greater time spent in gross anatomy laboratory during the laboratory portion of the course may have affected the study outcomes. In addition, some students may find the difference in (B+) versus (A-) grade as not practically significant. Further research needs to be conducted to identify what specific anatomy teaching resources are most effective beyond prosection for students without access to a gross anatomy laboratory.
Military Essentiality of Naval Aviation Repair Parts

This paper deals with the problem of ranking items according to their worth, where each item has associated with it a vector of attributes. In particular, a ranking system is developed and tested for aviation repair parts. The objective of the study is to determine whether some items are more important than others for the accomplishment of aircraft missions. If items differ in essentiality, it is important to take such differences into account in providing logistics support. The essentiality ranking is made by generating a vector of attributes for each repair part on the basis of human judgments. These judgments are obtained using a questionnaire which explicitly establishes the ground rules for making attribute assignments. Judgmental priority rules are then applied to the vectors to rank the items. The proposed methodology was tested for four configurations of aircraft. In the course of the study, a wide dispersion in the essentiality of repair parts was found. Of equal significance, a high degree of consistency was also noted among a large number of respondents. The ranking procedure, although designed for military aircraft, has other applications, including commercial ones. Such applications are appropriate whenever budgetary or other considerations require a priority system for allocating resources, e.g., in the procurement and distribution of material stocks including repair parts.
Functional DNA demethylation is accompanied by chromatin accessibility

DNA methylation inhibitors such as 5-aza-2'-deoxycytidine (5-Aza-CdR) are currently used for the treatment of myelodysplastic syndrome. Although global DNA demethylation has been observed after treatment, it is unclear to what extent demethylation induces changes in nucleosome occupancy, a key determinant of gene expression. We use the colorectal cancer cell line HCT116 as a model to address this question and determine that <2% of regions demethylated by 5-Aza-CdR treatment assume an open configuration. Consolidating our findings, we detect nucleosome retention at sites of global DNA methylation loss in DKO1, an HCT116-derived non-tumorigenic cell-line engineered for DNA methyltransferase disruption. Notably, regions that are open in both HCT116 cells after treatment and in DKO1 cells include promoters belonging to tumor suppressors and genes under-expressed in colorectal cancers. Our results indicate that only a minority of demethylated promoters are associated with nucleosome remodeling, and these could potentially be the epigenetic drivers causing the loss of tumorigenicity. Furthermore, we show that the chromatin opening induced by the histone deacetylase inhibitor suberoylanilide hydroxamic acid has strikingly distinct targets compared with those of 5-Aza-CdR, providing a mechanistic explanation for the importance of combinatorial therapy in eliciting maximal de-repression of the cancer epigenome.
Huddling by Rat Pups: Group Behavioral Mechanisms of Temperature Regulation and Energy Conservation

Body heat loss was attenuated and oxygen consumption was reduced by huddling in litters of developing rats. Rat pups derive physiological benefits from huddling similar to those enjoyed by adult mammals; these findings contrast with previous characterizations of the altricial rat as poikilothermic. Huddling insulates by lessening the exposed body surface area of the participants, thus retarding heat loss and enhancing the efficiency of thermogenesis . These physical mechanisms of the clump are actively regulated by the pups. A novel quantitative measure of huddle size revealed a form of group regulatory behavior in rat pups whereby the surface expanded and contracted with increases and decreases in ambient temperature. The individual basis of this group regulatory activity was investigated by marking individual pups and observing them in huddles by means of time-lapse videography. It was found that individual animals circulate through the huddle, frequently exchanging locations in the group. By studying the huddle positions of an anesthetized pup and a marked control sibling, dynamics of the pup flow were clarified. Ordinarily, the direction of movement was actively downward, into the pile; immobile pups "floated" on the surface. When the nest temperature was raised to thermoneutral, the direction of pup flow reversed and an immobile animal sank to the depths of the huddle. Through individual competitive adjustments the huddle behaves as a self-regulating unit which provides warmth and insulation to all its active members.
Near-Surface Vortex Intensification through Corner Flow Collapse

Abstract Results are presented from a large set of large-eddy simulations of a class of unsteady vortex evolution that may sometimes play a role in tornadogenesis or tornado variability. Beginning with a high-swirl parent vortex with an excess of low-swirl flow through the surface/corner/core region, perturbation of the low-swirl near-surface inflow at a large radius can trigger a subsequent dynamic “corner flow collapse” producing dramatic near-surface intensification relative to conditions aloft of an order of magnitude or more in velocity scale. This paper presents a more detailed treatment of the physics and simulation of corner flow collapse, expanding upon the presentation given in a companion paper treating near-surface vortex intensification more generally for both steady and unsteady conditions. The basic scaling of the onset, intensification, structure, and duration of the phenomenon is explored as a function of some of the dominant physical parameters involved. A dimensionless rate of change of...
Multiple attractors via CUSP bifurcation in periodically varying environments

Periodically forced (non-autonomous) single species population models support multiple attractors via tangent bifurcations, where the corresponding autonomous models support single attractors. Elaydi and Sacker obtained conditions for the existence of single attractors in periodically forced discrete-time models. In this paper, the Cusp Bifurcation Theorem is used to provide a general framework for the occurrence of multiple attractors in such periodic dynamical systems.
Managing computer networks using peer-to-peer technologies

Peer-to-peer systems and network management are usually related to each other because the traffic loads of P2P systems have to be controlled to avoid regular network services becoming unavailable due to network congestion. In this context, from a network operation point of view, P2P systems often mean problems. In this article we take a different perspective and look at P2P technologies as an alternative to improve current network management solutions. We introduce an approach where P2P networks are used as flexible interdomain distributed management systems able to provide facilities often absent in traditional management systems. We present three examples of P2P-based network management: how managed network views can be shared in a P2P network, how P2P-based application layer routing can improve connectivity between management entities, and how groups of peers can be used to process management tasks in a balanced way. Our main goal is to show that P2P technologies are a feasible tool for network management, and thus motivate further investigations on the subject.
Numerical Drag Reduction Studies of Generic Truck Models Using Active Flow Control

The effect of active flow control (AFC), using oscillatory blowing (synthetic jets) and steady suction/blowing, on drag reduction of cars/trucks is numerically studied using the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations. Three generic models of trucks for which the experimental data are available are considered in the simulations. CFD simulations are in good agreement with the data. Both the experiments and simulations show that 10 to 15% reduction in drag can be achieved by active flow control using oscillatory blowing. A combination of oscillatory blowing and steady blowing or suction at appropriate locations on the rear face of the truck can further reduce the drag. These studies indicate that the AFC techniques can be intelligently employed to achieve significant reduction in aerodynamic drag of the vehicle.
The Mulatto Advantage: The Biological Consequences of Complexion in Rural Antebellum Virginia

Although historians have long noted that African-Americans of mixed-race in the antebellum Lower South were given economic and social preference over those with darker skin, they have denied that people of mixed race received special treatment in the antebellum Upper South as well. Examination of data on the registrations of free African-Americans in antebellum Virginia, however, reveals that adolescents and adults with lighter complexions tended to have a height advantage, which suggests that they enjoyed better nutrition.
On the number of training points needed for adequate training of feedforward neural networks

The authors address the problem of training neural networks to act as approximations of continuous mappings. In the case where the only representation of the mapping within the training process is through a finite set of training points, they show that in order for this set of points to provide an adequate representation of the mapping, it must contain a number of points which rises at least exponentially quickly with the dimension of the input space. Thus they also show that the time taken to train the networks will rise at least exponentially quickly with the dimension of the input. They conclude that if the only training algorithms available rely upon a finite training set, then the application of neural networks to the approximation problem is impractical whenever the dimension of the input is large. By extrapolating their experimental results, they estimate that 'large' in this respect means 'greater than ten'. >
Arf guanine nucleotide-exchange factors BIG1 and BIG2 regulate nonmuscle myosin IIA activity by anchoring myosin phosphatase complex

Brefeldin A-inhibited guanine nucleotide-exchange factors BIG1 and BIG2 activate, through their Sec7 domains, ADP ribosylation factors (Arfs) by accelerating the replacement of Arf-bound GDP with GTP for initiation of vesicular transport or activation of specific enzymes that modify important phospholipids. They are also implicated in regulation of cell polarization and actin dynamics for directed migration. Reciprocal coimmunoprecipitation of endogenous HeLa cell BIG1 and BIG2 with myosin IIA was demonstrably independent of Arf guanine nucleotide-exchange factor activity, because effects of BIG1 and BIG2 depletion were reversed by overexpression of the cognate BIG molecule C-terminal sequence that follows the Arf activation site. Selective depletion of BIG1 or BIG2 enhanced specific phosphorylation of myosin regulatory light chain (T18/S19) and F-actin content, which impaired cell migration in Transwell assays. Our data are clear evidence of these newly recognized functions for BIG1 and BIG2 in transduction or integration of mechanical signals from integrin adhesions and myosin IIA-dependent actin dynamics. Thus, by anchoring or scaffolding the assembly, organization, and efficient operation of multimolecular myosin phosphatase complexes that include myosin IIA, protein phosphatase 1δ, and myosin phosphatase-targeting subunit 1, BIG1 and BIG2 serve to integrate diverse biophysical and biochemical events in cells.
Optic pathway gliomas: a review

Optic pathway gliomas represent approximately 3-5% of childhood intracranial tumors. They usually occur in children during the first decade of life and are seen in 11-30% of patients with neurofibromatosis Type 1 (NF1). Although these tumors are typically low-grade gliomas, the clinical course and natural history are highly variable, making treatment paradigms difficult. Overall, however, they are often indolent tumors that can be observed over time for progression without initial treatment, especially in patients with NF1. Chemotherapy is the first-line treatment for progressive tumors, and radiation therapy is reserved for patients with progressive disease who are older than 5-7 years. Surgery is reserved for large tumors causing mass effect or hydrocephalus and tumors confined to the orbit or unilateral optic nerve.
Tissue engineering of the meniscus: Scaffolds for meniscus repair and replacement

The menisci homogenously distribute load throughout the knee joint. Partial or total removal of the menisci significantly alters the biomechanical properties of the knee, leading to osteoarthritis and articular cartilage (AC) degeneration. Many synthetic and natural materials have been tested to find a scaffold that can withstand the natural mechanical forces on the joint. However, currently there are few meniscus tissue (MT) replacements available for clinical use. This review addresses tissue engineering (TE) of the meniscus, with a primary focus on tissue engineered scaffolds (TESs) as current and future models for meniscus replacement. Our review also discusses implant fixation, an area which we believe must be improved in order for meniscal replacements to be successful in vivo.
Optical Temperature Sensors

The objective of this review of fiber-optic temperature sensors is to illustrate, through examples, each of the most prominent sensing techniques. The benefits of fiber optics are fully realized only if the remotely located sensor is linked solely by fibers, therefore, this chapter will not discuss sensors that require electrical power connections. Fully fiber optical temperature sensors can be categorized on the basis of their signal generation method as follows: 1 Optically emissive, thermally powered 2 Optically emissive, optically powered 3 Non-emissive, intensity modulating
Generalized Method of Moments for Samples of Unequal Length

ThispaperextendsthegeneralizedmethodofmomentstechniqueofHansen(1982)tocases where moment conditions are observed over difierent sample periods. Many applications in flnancial economics use data series that have difierent starting dates or difierent ending dates. Common practice is to take the intersection of the sample periods over which the data are observed; the intersection then becomes the sample period for the study and the rest of the data areignored. Thispaperdescribesanalternativethatallowstheresearchertomakeuseofallof the data available for each moment condition. We describe two asymptotically equivalent estimatorsandshowthattheseestimatorsareconsistent,asymptoticallynormal,andmoree‐cient asymptotically than standard GMM. We then extend both of these estimators to settings with moregeneralpatternsofmissingdataandshowthattheextendedestimatorsareasymptotically more e‐cient than estimators that ignore intervals of the sample, even if some series are not observed over all these intervals. By implication, the extended estimators are more e‐cient than standard GMM.
ICP0 Is Required for Efficient Reactivation of Herpes Simplex Virus Type 1 from Neuronal Latency

Relative to wild-type herpes simplex virus type 1 (HSV-1), ICP0-null mutant viruses reactivate inefficiently from explanted, latently infected mouse trigeminal ganglia (TG), indicating that ICP0 is not essential for reactivation but plays a central role in enhancing the efficiency of reactivation. The validity of these findings has been questioned, however, because the replication of ICP0-null mutants is impaired in animal models during the establishment of latency, such that fewer mutant genomes than wild-type genomes are present in latently infected mouse TG. Therefore, the reduced number of mutant viral genomes available to reactivate, rather than mutations in the ICP0 gene per se, may be responsible for the reduced reactivation efficiency of ICP0-null mutants. We have recently demonstrated that optimization of the size of the ICP0 mutant virus inoculum and transient immunosuppression of mutant-infected mice with cyclophosphamide can be used to establish wild-type levels of ICP0-null mutant genomes in latently infected TG (W. P. Halford and P. A. Schaffer, J. Virol. 74:5957-5967, 2000). Using this procedure to equalize mutant and wild-type genome numbers, the goal of the present study was to determine if, relative to wild-type virus, the absence of ICP0 function in two ICP0-null mutants, n212 and 7134, affects reactivation efficiency from (i) explants of latently infected TG and (ii) primary cultures of latently infected TG cells. Although equivalent numbers of viral genomes were present in TG of mice latently infected with either wild-type or mutant viruses, reactivation of n212 and 7134 from heat-stressed TG explants was inefficient (31 and 37% reactivation, respectively) relative to reactivation of wild-type virus (KOS) (95%). Similarly, n212 and 7134 reactivated inefficiently from primary cultures of dissociated TG cells plated directly after removal from the mouse (7 and 4% reactivation, respectively), relative to KOS (60% reactivation). The efficiency and kinetics of reactivation of KOS, n212, and 7134 from cultured TG cells (treated with acyclovir to facilitate the establishment of latency) in response to heat stress or superinfection with a nonreplicating HSV-1 ICP4(-) mutant, n12, were compared. Whereas heat stress induced reactivation of KOS from 69% of latently infected TG cell cultures, reactivation of n212 and 7134 was detected in only 1 and 7% of cultures, respectively. In contrast, superinfection with the ICP4(-) virus, which expresses high levels of ICP0, resulted in the production of infectious virus in nearly 100% of cultures latently infected with KOS, n212, or 7134 within 72 h. Thus, although latent mutant viral genome loads were equivalent to that of wild-type virus, in the absence of ICP0, n212 and 7134 reactivated inefficiently from latently infected TG cells during culture establishment and following heat stress. Collectively, these findings demonstrate that ICP0 is required to induce efficient reactivation of HSV-1 from neuronal latency.
The what and where in visual masking.

Abstract A metacontrast mask suppresses the visibility of, without influencing the reaction time (RT) to, the target. We investigated whether this dissociation results from a sensori-motor pathway immune to masking effects or from the characteristics of stimulus timing in mutually inhibitory sustained and transient channels. For target visibility, para- and metacontrast yielded the usual U-shaped functions. Peak paracontrast occurred at stimulus onset asynchronies (SOAs) of −150 to −100 ms. RTs were relatively low for metacontrast and did not show a systematic change as a function of SOA. The RT contribution from contour-masking was greatest at an SOA of −150 ms (paracontrast) and declined to near zero in the metacontrast regime. The dissociation between visibility and RT seen in metacontrast did not occur in paracontrast, rejecting the theory that RTs are elicited by a single sensori-motor pathway immune to masking. The dependence of the dissociation on stimulus timing can be explained by RECOD, a dual-pathway model wherein fast and slow activities interact.
Microgravity opposed-flow flame spread in polyvinyl chloride tubes

The effects of gravity on opposed-flow flame spread in a confined geometry were investigated experimentally in the 2.2-s drop tower at the NASA Glenn Research Center. Pure oxygen flowed through samples of 0.64-cminner-diameter polyvinyl chloride (PVC) tubing held either horizontally or vertically in a combustion chamber filled with nitrogen. The sample was ignited in normal gravity with a hot wire, and once a flame was established, the apparatus was dropped to observe microgravity effects. Flame spread rate was measured in normal and microgravity at pressures of 1.0 and 0.5 atm. A low-flow ignition limit was observed at an opposed-flow velocity of 1.36 cm/s, at which point the horizontal, vertical, and microgravity flame spread rates were 0.40, 0.30, and 0.16 cm/s, respectively. For flow velocities above approximately 5.2 cm/s, there was no difference in the flame spread rates for normal and microgravity and the flame spread rate increased with a nearly square root dependence with respect to opposed-flow velocity. Buoyant flow velocities of 2.5 and 1.5 cm/s were estimated for horizontal and vertical flames, respectively. Vertical tests conducted at 0.5 atm pressure demonstrated no difference in flame spread rate between normal and microgravity. These results suggest that the fire risk associated with the use of PVC tubes during general anesthesia in either space or ground applications may be reduced if the application of a high-energy surgical tool is prevented during an active phase of the breathing cycle (inhale or exhale).
Tensor to scalar ratio in nonminimal φ 4 inflation

We reconsider nonminimal λφ 4 chaotic inflation which includes the gravitational coupling term ξℜφ 2 , where φ denotes a gauge singlet inflaton field and ℜ is the Ricci scalar. For ξ ≫ 1, we require, following recent discussions, that the energy scale λ 1/4mP/√ξ for inflation should not exceed the effective UV cutoff scale m P /ξ, where m P denotes the reduced Planck scale. The predictions for the tensor-to-scalar ratio r and the scalar spectral index n s are found to lie within the Wilkinson Microwave Anisotropy Probe 1-σ bounds for 10 -12 ≲ λ ≲ 10 -4 and 10 -3 ≲ ξ ≲ 10 2 . In contrast, the corresponding predictions of minimal λφ 4 chaotic inflation lie outside the Wilkinson Microwave Anisotropy Probe 2-σ bounds. We also find that r ≳ 0.002, provided the scalar spectral index n s ≥ 0.96. In estimating the lower bound on r, we take into account possible modifications due to quantum corrections of the tree level inflationary potential.
The Black-Scholes Model Guideline For Options Course As Taught At Notre Dame University - Lebanon

This paper presents the methodology used for Notre Dame University’s finance students to explain and explore the Black-Scholes model without going through the complexity of mathematics to model random movements or through stochastic calculus. I will name and develop the steps that I follow in order to allow students to properly use the Black-Scholes model and to understand the relationship of the model’s inputs to the option price while monitoring the risk via delta and gamma hedging.
The role of micro-organisms and biofilms in dysfunctional wound healing

Abstract: The relationship of microbes and wounds has always been controversial; the unmasking of biofilms as the primary mechanism of microbial pathogenicity in chronic wounds has only heightened this controversy. Here, we attempted to give credence and data to support this theme-heightened hypothesis, utilizing: 1) “universal microbial principles” that are constant, independent of the site of infection; 2) integrating new terms and definitions reflective of updated microbial methods, detection, and modeling (pre-clinical trials); and 3) organized this education into four sections. Each section builds on the previous theme, with the final section revisiting the consequences of wound pathogenesis, focusing rather, on the benefits of a microbial biofilm (probiotics) and inhibition of planktonic, traditional wound pathogens.
[ZnSe(dbn)1/2] and [ZnSe(hda)1/2]: Two new members of inorganic-organic hybrid semiconductor nanocomposites exhibiting a strong quantum confinement effect

Two new inorganic-organic hybrid II-VI semiconductor nanostructures have been synthesized by solvothermal reactions. These nanostructures consist of inorganic 2 ∞[ZnSe] layers and organic bridging diamine molecules as spacers. The crystal structures of [ZnSe(dbn)1/2](1, dbn = 1,4-diaminobutane) and [ZnSe(hda)1/2](2, hda = 1,6-hexanediamine) have been determined by the powder X-ray diffraction method. They are isostructural and crystallize in the orthorhombic crystal system, space group Pbca(No.62), Z = 4. Crystal data for 1: a = 6.646(3), b = 6.473(3), c = 22.31(1) A, V = 961.2(13) A3, for 2: a = 6.6252(18), b = 6.4505(17), c = 27.138(7) A, V = 1159.8(9) A3. The optical absorption experiments show that both 1 and 2 generate a very large blue shift in the absorption edge (1.5-1.6 eV) due to a strong quantum confinement effect (QCE). Thermogravimetric behavior of both compounds has also been investigated.
Differences in Patterns of Reproductive Allocation between the Sexes in Nicrophorus orbicollis

Organisms are selected to maximize lifetime reproductive success by balancing the costs of current reproduction with costs to future survival and fecundity. Males and females typically face different reproductive costs, which makes comparisons of their reproductive strategies difficult. Burying beetles provide a unique system that allows us to compare the costs of reproduction between the sexes because males and females are capable of raising offspring together or alone and carcass preparation and offspring care represent the majority of reproductive costs for both sexes. Because both sexes perform the same functions of carcass preparation and offspring care, we predict that they would experience similar costs and have similar life history patterns. In this study we assess the cost of reproduction in male Nicrophorus orbicollis and compare to patterns observed in females. We compare the reproductive strategies of single males and females that provided pre- and post-hatching parental care. There is a cost to reproduction for both males and females, but the sexes respond to these costs differently. Females match brood size with carcass size, and thus maximize the lifetime number of offspring on a given size carcass. Males cull proportionately more offspring on all carcass sizes, and thus have a lower lifetime number of offspring compared to females. Females exhibit an adaptive reproductive strategy based on resource availability, but male reproductive strategies are not adaptive in relation to resource availability.
Shifting Sands: An AIDS Service Organization Adapts to a Changing Environment

This paper focuses on effects of the changing HIV/AIDS environment on AIDS service organizations (ASOs). The need for ASOs remains strong; however, in anticipation of reduced public support and funding for community services, strategies for organizational survival are needed. The policy and funding background of shifting priorities in the HIV/AIDS epidemic are presented as well as a case study describing an organizational change process that was used in response to an anticipated threat to organizational survival.