cssi/SciSciGPT-SciSciNet huggingface dataset:
Molecular Dynamics of Pyridine Adsorbed on the Silica Surface

The molecular dynamics of pyridine adsorbed onto dry high-surface-area silica gel was studied using solid-state deuterium NMR spectroscopy. Selectively and totally deuterated pyridine samples were used to identify the spectral signatures associated with each ring location and to identify the dynamical modes present in the surface adsorbed species. Loading levels corresponding to 0.8 and 0.2 monolayer coverage were studied. At 174 K and 0.8 monolayer, the adsorbed pyridine molecules are found in three motional modes: a fraction is found to be static, a larger fraction is found executing fast discontinuous rotation (180° ring flips) about the pyridine Cγ−N axis, and a very small fraction is found in fast continuous rotation (diffusion) about the pyridine Cγ−N axis, all referred to a 5 × 10-6 s time scale. No evidence of O−H−N rotation about the Si−O bond (“swinging arm” motion) is observed. The pyridine flips and rotations permit measurement of the angle between the Cγ−N axis and each of the Cα−D and Cβ−D ...
Mechanically induced focal adhesion assembly amplifies anti-adipogenic pathways in mesenchymal stem cells

The fate of pluripotent mesenchymal stem cells (MSC) is determined through integration of chemical, spatial, and physical signals. The suppression of MSC adipogenesis by mechanical stimuli, which requires Akt-induced inhibition of glycogen synthase kinase 3β (GSK3β) with β-catenin activation, can be enhanced by repetitive dosing within a single day. Here, we demonstrate that reapplication of cyclic strain within a 24-hour period leads to amplification of both Akt activation and its subsequent inhibition of GSK3β, such that total cycle number can be reduced while still inhibiting adipogenesis. Amplification of Akt signaling is facilitated by a dynamic restructuring of the cell in response to mechanical signals, as evidenced by a transient increase in focal adhesion (FA) number and increased RhoA activity. Preventing FA assembly or development of tension blocks activation of Akt by mechanical signals, but not by insulin. This indicates that the FA infrastructure is essential to the physical, but not necessarily the chemical, sensitivity, and responsiveness of the cell. Exploiting the transient nature of cytoskeletal remodeling may represent a process to enhance cell responsiveness to mechanical input and ultimately define the fate of MSCs with a minimal input.
A constraint‐stabilized time‐stepping approach for rigid multibody dynamics with joints, contact and friction

We present a method for achieving geometrical constraint stabilization for a linear-complementarity-based time-stepping scheme for rigid multibody dynamics with joints, contact, and friction. The method requires the solution of only one linear complementarity problem per step. We prove that the velocity stays bounded and that the constraint infeasibility is uniformly bounded in terms of the size of the time step and the current value of the velocity. Several examples, including one for joint-only systems, are used to demonstrate the constraint stabilization effect. Copyright © 2004 John Wiley & Sons, Ltd.
Collaboration for knowledge networking in development

The increasing globalization of the world economy has meant that people and organizations in different countries are becoming more dependent upon each other. In particular, access to information, expertise, and knowledge is a key determinant of those able to participate in the knowledge economy. In his book Runaway World: How Globalization is Reshaping Our Lives, Giddens (2003) suggests that information literacy is paramount for those wanting to survive in this interconnected world. He suggests that the more science and technology intrude into our lives, the more active or engaged our relationship to it becomes. International development agencies highlight problems of exclusion from the knowledge economy where know-how replaces land and capital as the basic building blocks of growth (United Nations Development Program, 2003; World Bank, 2003). A World Bank study found that 90%; of the world’s Internet subscribers are in countries whose population is 15%; of the global total (Dasgupta, Lall, & Wheeler, 2004). In a study of 178 nations in the world, the International Telecommunication Union devised a set of metrics called the Digital Access Index (DAI). The DAI is determined by such factors as education, the affordability of Internet access, the proportion of Internet users with high-speed connections, and the availability of bandwidth (Minges, Gray, & Magpantay, 2003). International development agencies recognize that in order to bridge this digital divide between the information rich and information poor, knowledge networking needs to take place. This means the people need access to information and expertise in order to create better livelihoods for themselves. It appears that collaboration processes can enhance the effects of information and communication technologies when applied to development efforts. Collaboration is defined as the shared creation and/or discovery in which two or more individuals with complementary skills interact to create shared understanding that none had previously possessed or could have come to on their own (Schrage, 1990). If information is required for the collaborative process to be productive, information has to be communicated and deliberated upon. In this sense, the process of accessing information demands attention and is a cognitive process. Briggs (1994) suggests that before team members can exchange or think about information, they must engage in the process of accessing the information they need. The process of accessing information also demands attention and because attention resources are limited, people need to collaborate. Often information and knowledge needed for development
Effects of air flow directions on composting process temperature profile.

Abstract In this study, chicken manure mixed with carnation wastes was composted by using three different air flow directions: R1-sucking (downward), R2-blowing (upward) and R3-mixed. The aim was to find out the most appropriate air flow direction type for composting to provide more homogenous temperature distribution in the reactors. The efficiency of each aeration method was evaluated by monitoring the evolution of parameters such as temperature, moisture content, CO 2 and O 2 ratio in the material and dry material losses. Aeration of the reactors was managed by radial fans. The results showed that R3 resulted in a more homogenous temperature distribution and high dry material loss throughout the composting process. The most heterogeneous temperature distribution and the lowest dry material loss were obtained in R2.
Resource-monotonic solutions to the problem of fair division when preferences are single-peaked

We consider the problem of fairly allocating an infinitely divisible commodity among a group of agents with single-peaked preferences. We search for solutions satisfying resource-monotonicity, the requirement that all agents be affected in the same direction when the amount to divide changes. Although there are resource-monotonic selections from the Pareto solution, there are none satisfying the distributional requirements of no-envy or individual rationality from equal division. We then consider the weakening of resource-monotonicity obtained by allowing only changes in the amount to divide that do not reverse the direction of the inequality between the amount to divide and the sum of the preferred amounts. We show that there is essentially a unique selection from the solution that associates with each economy its set of envy-free and efficient allocations satisfying this property of one-sided resource-monotonicity: it is the uniform rule, a solution that has played a central role in previous analyses of the problem.
The effects of a single dose of amphetamine and iprindole on the serotonergic system of the rat brain

Rats treated with iprindole (IPR) (10 mg/kg, i.p.) were given a single dose (15 mg/kg, i.p.) of amphetamine (AMP). Marked decreases in the activity of tryptophan hydroxylase (TPH) were observed in both the cerebral cortex and neostriatum after 6 hr, with maximum depression observed at 24 hr. Enzyme activity had returned to control levels in neostriatum after 3 days and in cerebral cortex after 7 days. Levels of serotonin (5-HT) in both the cerebral cortex and neostriatum were significantly lowered at 24 hr but had recovered by 72 hr. Levels of tryptophan (TRP) in the cortex were significantly elevated after 6 hr, recovering by 24 hr. In the neostriatum, the activity of tyrosine hydroxylase (TH) was significantly depressed by 24 hr and remained so for 7 days. Concentrations of dopamine (DA) were decreased at all times examined. This study clarifies the differences previously observed in the response of the serotonergic system to amphetamine or methamphetamine (METH) in iprindole-treated rats.
Iterative linear programming strategies for constrained simulation

Abstract With the development of powerful equation-oriented process simulators, such as SPEEDUP and ASCEND, much research deals with the development of reliable This approach performs very well on a number of small problems and has been implemented within a large-scale modelling system (GAMS). This allows an in It should be mentioned, however, that this algorithm can fail when the LP yields a zero search direction at a nonsolution point. We term this special c
Access‐related Infection and Pre‐infection Albumin in Hemodialysis

Infection of hemodialysis (HD) access is a major cause of morbidity and mortality. Certain conditions predisposing to infection (malnutrition, chronic inflammation) are associated with hypoalbuminemia. To test whether pre-existing hypoalbuminemia has any relationship with HD access infections, we analyzed the records of 87 patients on chronic HD who had access-related infection as the reason for hospital admission between July 1999 and June 2001. We obtained data on age, gender, pre-infection albumin levels, co-morbidities, complications, type of infection, infecting organism, mode of management and mortality. We compared average pre-infection albumin levels of 79 patients with access infection with those of 198 control patients on chronic HD during the study period without documented access infection. We also compared mortalities between patients with HD tunneled catheter infection treated with antibiotics alone and those treated with antibiotics plus access removal. The mean pre-infection serum albumin was lower in subjects with access infection than those without access infection (2.4 ± 0.6 vs. 3.2 ± 0.6 g/dL, P < 0.0001). Logistic regression including several clinical confounders among its candidate variables identified hypoalbuminemia as a strong predictor (P < 0.0001) of access infection. The odds ratio (OR) of access infection increased progressively with decreasing pre-infection serum albumin: OR of access infection was 8.0 (95% confidence interval {CI} 4.5–16.6) for albumin ≤ 3.0 g/L, 11.0 (95% CI 4.4–22.3) for albumin ≤ 2.5 g/dL, and 27.9 (95% CI 6.1–128.1) for albumin ≤ 2.0 g/dL. Women had a marginally higher chance of tunneled HD catheter infection than men (P = 0.08). Case mortality was 25%(4 in 16) in patients with tunneled HD catheter infection treated with antibiotics alone and 2.8%(2 in 71) in those treated with antibiotics plus access removal or change over a guide wire (P = 0.0096). Hypoalbuminemia, a predictor of adverse outcomes in HD, is associated with an increased risk of HD access infection. Women with tunneled HD catheter have a tendency to higher rates of access infection than men. Treatment of tunneled HD catheter infection with antibiotics alone is associated with increased risk of death.
Psychogenic dysphagia and globus: reevaluation of 23 patients.

Despite authoritative warnings against attributing dysphagia to psychologic causes [1, 2], patients referred to The Johns Hopkins Swallowing Center have frequently been diagnosed as having “psychogenic dysphagia” or “globus hystericus” on prior evaluation. We review the Swallowing Center experience in the re-evaluation of patients previously diagnosed as having symptoms of psychogenic origin.
13. Long-term effectiveness of intra-anal high-grade dysplasia ablation and near 100% prevention of progression to anal cancer

Background High-grade dysplasia (HSIL) is the anal squamous cell carcinoma (ASCC) precursor. Ablation with surgery, electro cautery (ECA) and infrared coagulation (IRC) might prevent ASCC. We endeavoured to determine long-term effectiveness of HSIL ablation and progression to ASCC. Methods: A retrospective chart review of patients undergoing HSIL ablation by any modality between February 1998 until May 2012. Results: In 456 HIV+ MSM (mean age 45 ± 9 years) and 271 HIV– MSM (mean age 41 ± 11years) followed for a mean of 3 (range 0.2–13) years, 1673 HSILs were treated by laser, IRC and/or ECA. ASCC developed in 5 (0.7%) MSM but only one (0.1%) was undergoing active treatment. For HIV+ MSM, recurrence after 1st, 2nd, 3rd and 4th treatment was 66%, 64%, 62% and 54%, respectively. For HIV– MSM, HSIL recurrence after the 1st, 2nd, 3rd and 4th treatment was 59%, 44%, 46% and 50%, respectively. Median number of recurrent lesions was never greater than 2 for HIV+ MSM and 1 for HIV– MSM. The cure rate of lesions treated once in HIV+ and HIV– MSM was 73% and 84%, respectively. KM curves demonstrate that most recurrence occurs within the first 12 months after treatment. Recurrence increased with HIV infection (HR 1.3; 95% CI: 1.1–1.6) and each additional lesion treated (HR 1.6; 95% CI: 1.1–1.2). Age and treatment modality did not affect recurrence. Conclusions: Patients undergoing active ablation for cure of intra-anal HSIL appear to have limited progression to ASCC. Recurrence remains high but falls over time and repeated treatment.
Tritiated uridine labeling of the retina: changes after retinal detachment.

Abstract As part of a study designed to examine the response of photoreceptor cells to outer segment injury (retinal detachment), the pattern of RNA labeling ([3H]uridine incorporation) has been determined in detached cat retinas. Retinas were experimentally detached from the adjacent cellular layer (the retinal pigment epithelium: RPE) by injecting fluid into the extracellular space between the retina and RPE. Twenty-four hours before the animals were killed they received intravitreal injections of [3H]uridine. Autoradiograms were prepared from plastic sections 1·0 μm thick taken from detached retinal regions and, because the detachments do not encompass all of the retina, from nearby attached retinal regions. Twenty-four hours after retinal detachment there is a decrease in labeling intensity of the photoreceptors and Muller's glia in the region of detachment (compared to cells in nearby attached regions). Seventy-two hours after retinal separation, the same result is obtained in the photoreceptors, but labeling intensity is greatly increased in both the nuclei and cytoplasm of Muller's glia. The decrease in [3H]uridine labeling of the photoreceptors correlates with a decreased staining intensity of the cytoplasm and ultrastructural signs of necrosis. The striking change in the pattern and intensity of labeling of the Muller cells precedes extensive hypertrophy of these cells and the appearance within their cytoplasm of numerous 10-nm diameter filaments. Two weeks, and also 1 month, after detachment the pattern and labeling levels are similar to those observed 1 day after retinal separation. These data suggest a highly localized change in metabolism because the change in RNA labeling is restricted to the region of detached retina.
Human erythrocyte acetylcholinesterase. I. Resolution of activity into two components.

Abstract 1. 1. Human erythrocyte acetylcholinesterase solubilized by Triton X-100 has been resolved into two components by DEAE-Sephadex column chromatography. The two partially purified enzymes have apparently identical molecular weights with different electrophoretic mobility. The Km values of the two components were shown not to differ significantly. 2. 2. The molecular weight of Triton-solubilized acetylcholinesterase was estimated by gel filtration, in the presence of Triton X-100, to be approx. 420 000. Following the removal of the detergent, the molecular weight of the enzyme was shown to be greater than 2·106.
Correlation of physicochemical parameters and biological activity in steroids. 9Alpha-substituted corticol derivatives.

Por primera vez se han analizado las relaciones estructura-funcion de diez derivados del 9α-cortisol substituido usando tecnicas de regresion de parametros multiples. Se concluye que los factores electronicos y estericos son de mayor importancia al determinar el efecto del substituyente, y que la union hidrofobica tambien es de importante consideracion. Se discute el significado de estos resultados.
Highly Stable Copolyimides for Second-Order Nonlinear Optics

Nonlinear optical (NLO) copolyimides exhibiting high glass transition temperatures (Tg) and high thermal stabilities were synthesized to achieve long-term stability of optical nonlinearity at elevated temperatures. The relationship between the chromophore loading level and the physical properties of the copolymers was studied. It was found that decreasing the chromophore loading level increased the glass transition temperature more than 40 °C. As a result, the stability of the electric field induced dipole orientation of the nonlinear optical chromophores was enhanced. The second harmonic generation (SHG) signal maintained 85% of its initial value after 700 h at 180 °C. Sizable second-order nonlinear optical coefficients and electro-optic coefficients were obtained.
Study of Vibration Energy of the Pile Driven in Two Layers Foundation Base, Pile Bearing Side Friction q1#q2 Pile Bottom Encounters Constant Resistance

Basing on the theory shock longitudinal of solid body into elastic bar, authors define speed of the piles weighting canter in shocking time, they also define kinetic energy of weighting canter and define vibration energy of the pile driven in two layers foundation base, pile bearing side friction q1#q2 pile bottom encounters constant resistance.
Coulomb Excitation of High-Spin States in 238 U

Coulomb excitation with Kr and Xe ions has excited the ground-state band of $^{238}\mathrm{U}$ up to the ${22}^{+}$ (tentatively ${24}^{+}$) state and the lowest octupole vibrational band up to ${19}^{\ensuremath{-}}$. No back-bending is observed. The behavior of the octupole band at high spins suggests a Coriolis-induced alignment of the rotational and vibrational angular momenta.
Occurrence of temperature inversions in the upper layer of the ocean

Bathythermograms just off the northern edge of the Gulf Stream often show temperature inversions, while those in the Gulf Stream and the Sargasso Sea do not show such features. A similar situation was found in the Kuroshio area. TheT-S curve obtained off Cape Hatteras with a bathysalinograph and a bathythermograph indicates that the temperature inversions correspond to high salinity and less stable density stratification. Sequential surface temperature charts suggest that the inversions may be caused by sinking of the warm and saline Gulf Stream water. When such water is driven into the slope water region, it is cooled by mixing or heat transfer to the atmosphere, but retains its high salinity and sinks. A simple mathematical model is developed based on an assumption that an isolated water mass is enclosed in a parcel with a flexible and permeable membrane. The initial density inside the parcel is different from the one outside and the water mixes with the surrounding water. When it is assumed that mixing of temperature occurs faster than that of salinity, the isolated Gulf Stream water sinks to an equilibrium depth, causing temperature peaks and inversions in the subsurface layer.
Oleic acid-induced Ca2+ mobilization in human platelets: Is oleic acid an intracellular messenger?

The purpose of this study was to explore the effect of oleic acid (OA) on intracellular Ca2+ mobilization in human platelets. When applied extracellularly, OA produced a concentration dependent rise in cytosolic [Ca2+] ([Ca2+]cyt) when extracellular [Ca2+] (Ca2+]ext) was zero (presence of EGTA), suggesting that OA caused an intracellular release of Ca2+. Intracellular Ca2+ release was directly proportional to entry of OA into platelets and OA entry was indirectly proportional to [Ca2+]ext. In permeabilized platelets, OA caused the release of 45Ca2+ from ATP dependent intracellular stores. Finally, our results show that thrombin stimulated the release of [3H]OA from platelet phospholipids. The saturated fatty acids stearic and palmitic acid did not stimulate an increase in [Ca2+]cyt under these conditions, but the unsaturated fatty acid, linolenic acid produced effects similar to those of OA, suggesting specificity among fatty acids for effects on [Ca2+]cyt. Taken together, our experiments suggest that OA which has been incorporated into platelet phospholipids was released into the cytosol by thrombin stimulation. Our experiments also show that OA stimulates Ca2+ release from intracellular stores. These results support the hypothesis that OA may serve as an intracellular messenger in human platelets.
Modifications of the hamstring transfer.

SUMMARY Continuing experience with the hamstring transfer and patellar retinacular release as originally described by Eggers has led to the development of graded modifications of the procedure which achieve a better balance between the knee extensors and the knee flexors and prevent, particularly, the common complication of genu recurvatum. RESUME Modifications du transfer! des muscles longs posterieurs de la cuisse Poursuivant Ľexperience concernant le transfert des muscles longs posterieurs de la cuisse et le relachement du ligament rotulien selon la description originale de Eggers, nous avons ete amenes a apporter graduellement quelques modifications qui assurent un meilleur equilibre entre les extenseurs et les flechisseurs du genou et previennent, en particulier, la complication commune du genu recurvatum. ZUSAMMENFASSUNG Modifikationen der Knieflechsen-Ubertragung Fortwahrende Erfahrung mit der Knieflechsen-Ubertragung und patellarer, retinakularer Auslosung, wie bei Eggers zuerst beschrieben, fuhrte zur Entwicklung abgestufter Modifikationen der Prozedur, die einen besseren Ausgleich zwischen den sich streckenden und sich zusammenziehenden Kniemuskeln erzielen und besonders die haufig auftretende Komplikation des genu recurvatum verhindern. Diese Modifikationen haben die Ergebnisse verbessert. RESUMEN Modificaciones de la transferencia del tendon de la corva Experiencia continuada de la transferencia del tendon de la corva y la soltura patelar retinacular, descrita en primer lugar por Eggers, ha motivado una evolucion de modificaciones graduadas del procedimiento, las cuales ganan un equilibrio mejor entre los extensores y los flexores de la rodilla e impiden sobre todo la complication frecuente de genu recurvatum. A consecuencia de estas modificaciones nuestros resultados han mejorado.
Self-Help Secondary Education • in Kenya

Diverse viewpoints on the role of education in the development of Third World countries have spawned a variety of theories of Third World education. Some scholars contend that Third World states are too weak and "fragile" to implement development programs for education, health, and other social services. This paper examines secondary education in Kenya with regard to issues of educational inequality and quality of education, emphasizing the role of civil society in the provision of education. The role of the state as a major actor in the provision of education, and additionally as a determinant of who gets the benefits from educational efforts of both the state and the civil society, is also discussed in detail. It is argued that despite the major expansion of secondary education, the overall provision of education remains inadequate in relation to equity considerations. Although impressive quantitative expansion has occurred, access to educational opportunities in Kenya is still not evenly distributed with respect to gender and region. With regard to regional inequalities in the provision of education, it clearly emerges from this analysis that educational benefits are distributed in favor of the economically and politically dominant districts and provinces in the country. It is argued that, despite the state's ceding of most of its influence on the educational arena to the civil society, educational outcomes are still largely determined, directly or indirectly, by structures instituted, or supported, by the state. The paper demonstrates how an intricate interplay of social, political, and economic factors has worked against the efforts of the state and the civil society to improve the quality of education and eradicate inequality in the provision of education in Kenya.
Dissolution/precipitation behavior of biphasic calcium phosphate ceramics in bone-forming culture conditions

Mesenchymal stem cells in combination with biphasic calcium phosphate ceramics, hydryoxyapatite/tricalcium phosphate ceramics, have been shown to induce bone formation in large, long bone defects. Gaining an understanding of the factors that may influence stem cell differentiation on these ceramics is important for developing improved scaffold materials. The objective of this study was to characterize the dissolution/precipitation behavior of calcium from this ceramic in conditions that simulate MSC differentiation into bone cells in vitro. 20/80 and 60/40 HA/TCP ceramics were immersed in control media (DMEM, 10% fetal bovine serum), OS media (control media containing dexamethasone, /spl beta/-glycerophosphate, and ascorbic acid), or OS without dexamethasone. Ceramics were maintained in the media for up to 28 days at 37/spl deg/C, 5% CO/sub 2/, 95% humidity. The calcium level in the media was determined at days 4, 7, 14, 21 and 28 days. Calcium levels in the control media containing either ceramic dropped significantly over time as compared with control media prior to the immersion of the ceramic (day 0). The calcium level in the media containing 20/80 HA/TCP decreased the least as compared to 60/40 ceramics. The loss in calcium from the media indicates precipitation on the ceramic surface. These reactions may have an effect on MSC growth and differentiation.
An intelligent physical layer for cognitive radio networks

In this paper, we present an intelligent physical layer for cognitive mesh networks. It is well recognized that wireless mesh networks suffer from the inherent property of per hop delay attributed to store and forward routing and channel contention. We show that an intelligent physical layer coupled with efficient traffic engineering and channel allocation mechanism will reduce latency. In this paper, we discuss the evolution of an OFDM receiver, with sufficient software control to aid reconfigurability, capable of receiving and decoding information on different set of subcarriers, and also capable of switching the incoming signals to a different part of the available spectrum on the fly. Equipped with this enhanced receiver we propose a mechanism for wireless worm-hole routing, which employs frequency domain switching between subchannels where each subchannel is defined by a set of subcarriers. The OFDM receiver handles three primitives: transmit, receive and relay rather than just transmit or receive. Instead of a contention based, store and forward routing, a relay oriented physical layer has been proposed to reduce latency. The processing pipeline at an intermediate node no longer involves higher layer processing, and the hardware relays the incoming signal on-the-fly to a different part of the spectrum allowing for a full duplex transmission as the transmitter can relay signals while it is receiving on a different subchannel.
Local ecology and geographic ranges of plants in the Bishop Creek watershed of the eastern Sierra Nevada, California, USA

Aim The physiological requirements and tolerances of a species partially determine both its habitat preferences within a community and its broader geographic range. Therefore, we predicted that local ecology should be correlated with geographic distribution. We tested for a correlation between local ecology and range size, and we attempted to account for this correlation by the climate of the range. Location Bishop Creek Watershed, on the eastern side of the Sierra Nevada, California. Methods We recorded all plant species growing in each of 263 plots in the montane to alpine zones of the watershed. The local habitat preferences of 282 species were described in terms of wetness, elevation, soil, and amount of shade. The size and centre of the geographic range for each species were determined from regional floras. Results Wetness preference within the watershed was significantly correlated with range size. Specifically, plants of wet sites had larger ranges that extend to the north, whereas plants of dry sites tended to have smaller ranges centred to the east. The correlation between local wetness preference and range size was entirely explained by the location of the range centre of the species. Main conclusions A possible reason for the large ranges of mesophilic plants in our study area is that mesic habitats are continuous throughout the western Cordillera, while dry alpine habitats are isolated by valleys to the east. The correspondence between local ecology and geographic distributions implies evolutionary stasis in the niches of these plant species.
Enzyme Dynamics: Consensus and Controversy

A vigorous contemporary debate spotlights the role of protein dynamics in enzyme catalysis [1-7]. By the end of the day, the controversy goes down to statements that obviously do not agree with each other, such as “enzyme dynamics do (or do not) contribute to catalysis”. However, as the researchers studying this issue come from very different fields (kinetics, spectroscopy, theory, computer simulations, etc.) it is important to distinguish between “semantic disagreements” resulting from different terminologies, and matters of scientific merit (i.e., how enzymes work). Below I try to clarify points of agreement that sometimes go unrecognized, and sharpen the disagreements on matters of merit.
The University and the Health of Children

"It is the argument of this article that those responsible for the health and well-being of children need to muster the political will, and mount an effective social strategy, to forge different kinds of partnerships with allies in higher education."
H3K9 Methylation Regulates Growth and Development in Aspergillus fumigatus

In most species, chromatin remodeling mediates critical biological processes ranging from development to disease states. In fungi within the genus Aspergillus, chromatin remodeling may regulate expression of metabolic gene clusters, but other processes regulated by chromatin structure remain to be elucidated. In many eukaryotic species, methylation of lysine 9 of histone 3 (H3K9) is a hallmark of heterochromatin formation and subsequent gene silencing. The sole H3K9 methyltransferase in Schizosaccharomyces pombe is Clr4. We report that disruption of the Clr4 homolog in the pathogenic mold Aspergillus fumigatus (ClrD), which is involved in both mono- and trimethylation of H3K9, results in several growth abnormalities. Developmental defects in ΔAfclrD include reduction in radial growth, reduction in conidial production, and delayed conidiation after developmental competence mediated by delayed expression of brlA, the master regulator of conidiophore development. Sensitivity of ΔAfclrD to 6-azauracil suggests that ClrD influences transcriptional processing in A. fumigatus. Despite growth abnormalities, macrophage assays suggest ClrD may be dispensable for host interactions.
An expression for the S-parameters of arbitrarily oriented microstrip lines

An approximate expression for the coupled S-parameters of skew microstrip lines is derived. The expression is compared to a standard model for parallel coupled lines. An experiment designed to test the approximation for skew lines is described, and good agreement between measured and predicted results is found. >
Testing transient voltage surge suppressors

It is pointed out that there is growing recognition that surge interference, due both to lightning and to switching transients, is a major cause of equipment malfunction and damage. As a result, the transient voltage surge suppressor has received increasing attention and use. However, its electrical environment-high currents and voltages-can make measurements of its performance difficult. Areas of concern include fixturing, grounds, differential measurements, probes, oscilloscopes, and powered surging. Also of interest are methods for checking the measuring setup for noise, common-mode rejection and fixturing to insure valid data. Finally, it is noted that adequate consideration for safety must underlie all surge test plans. >
Optimization-Based Probabilistic Consequence Scenario Construction for Lifeline Systems

The construction of a suite of consequence scenarios that is consistent with the joint distribution of damage to a lifeline system is critical to properly estimating regional loss after an earthqua...
Training set expansion

Motivation: An important problem in systems biology is reconstructing complete networks of interactions between biological objects by extrapolating from a few known interactions as examples. While there are many computational techniques proposed for this network reconstruction task, their accuracy is consistently limited by the small number of high-confidence examples, and the uneven distribution of these examples across the potential interaction space, with some objects having many known interactions and others few. Results: To address this issue, we propose two computational methods based on the concept of training set expansion. They work particularly effectively in conjunction with kernel approaches, which are a popular class of approaches for fusing together many disparate types of features. Both our methods are based on semi-supervised learning and involve augmenting the limited number of gold-standard training instances with carefully chosen and highly confident auxiliary examples. The first method, prediction propagation, propagates highly confident predictions of one local model to another as the auxiliary examples, thus learning from information-rich regions of the training network to help predict the information-poor regions. The second method, kernel initialization, takes the most similar and most dissimilar objects of each object in a global kernel as the auxiliary examples. Using several sets of experimentally verified protein–protein interactions from yeast, we show that training set expansion gives a measurable performance gain over a number of representative, state-of-the-art network reconstruction methods, and it can correctly identify some interactions that are ranked low by other methods due to the lack of training examples of the involved proteins. Contact: mark.gerstein@yale.edu Availability: The datasets and additional materials can be found at http://networks.gersteinlab.org/tse.
Characterization of FLITECAM: the first light camera for SOFIA

Preliminary test results are reported for FLITECAM, the First Light Camera for SOFIA. This instrument is designed to perform imaging from 1 to 5 μm over the entire 8 arcmin field of view of SOFIA with 0.47arcsec pixels. The detector is a 1024 × 1024 InSb array, and large refractive optics are used for collimation and re-imaging. FLITECAM also has a pupil-viewing mode optimized for 3.5 mm and can accommodate grisms for slit spectroscopy. The instrument has passed Critical Airworthiness Design Review and has received the first part of its certificate of conformity. Ground-based tests of the finished instrument are planned for later in 2002 at the Lick Observatory 3-m Shane Telescope to verify that the point spread function meets its required FWHM of 1 arcsec over the full field and wavelength range. FLITECAM will be used to test the image quality and background of the SOFIA telescope, as well as for science applications.
1‐ethoxy‐3‐trifluoromethyl‐1,3‐Butadiene

[455941-77-2] C7H9OF3 (MW 166.14) InChI = 1S/C7H9F3O/c1-3-11-5-4-6(2)7(8,9)10/h4-5H,2-3H2,1H3 InChIKey = GBDJZMNUWNFRIF-UHFFFAOYSA-N (diene in Diels-Alder reaction) Physical Data: bp 44–46 °C/45 mm; nD20 1.4032. Solubility: soluble in most organic solvents. Form Supplied In: colorless liquid. Analysis of Reagent Purity: GC, 1H NMR, 19F NMR, combustion analysis. Preparative Methods: prepared by Wittig olefination of 4-ethoxy-1,1,1-trifluoro-3-buten-2-one (eq 1).1 The crude yield is approximately 75%. Upon distillation, the product is isolated in 43% yield. (1) Purification: after filtration through silica gel, the reagent is purified by distillation in the presence of hydroquinone. Handling, Storage, and Precaution: as implied above, the reagent is prone to oxidation, polymerization, and hydrolysis. It should be freshly prepared and stored under inert conditions.
Quantifying contributions to stream salinity using electromagnetic induction and hydrochemistry in a small Texas coastal-plain basin

Abstract Airborne, ground, and borehole electromagnetic (EM) induction measurements were combined with surface-water chemical analyses to determine the extent of salinization as well as identify salinity sources and migration mechanisms that elevate total dissolved solids (TDS), Cl−, and SO 4 2 - concentrations in Petronila Creek, a shallow stream that drains a small (1600 km2) basin on the Texas coastal plain. A multifrequency airborne EM induction survey measured apparent electrical conductivity of the ground to depths of a few tens of meters along the axis of the stream and along parallel flight lines within a 150 km2 area extending from where the stream is fresh to the estuarine mixing zone. Apparent conductivity sections and maps were analyzed to identify stream segments where high conductivity indicates near-surface salinization and where saline baseflow increases the salinity load. Elevated conductivities at shallow depths beneath the stream lie adjacent to extensive conductive areas in oil fields and along ditches that once carried brine produced from the oil fields. These highly conductive areas delineate salinization that dominantly is caused by past discharge of produced brine into ditches and pits, infiltration into sandy, permeable horizons, lateral subsurface migration, and eventual discharge into the stream. Streamflow measurements and chemical analyses show that the TDS load increased along two highly conductive streambed segments upstream from the estuarine mixing zone. Extensive salinization between the ditches and the stream could provide a continuing source of salinity. A third highly conductive segment coincides with the zone of estuarine mixing, where there is geophysical evidence of possible subsurface seawater intrusion. Multifrequency EM induction spectral images (the sectional depiction of apparent conductivity measured at multiple frequencies) along the stream axis, produced with minimal geophysical processing, helped identify stream segments that receive saline baseflow and guided surface-water sampling that allowed quantification of salinity loads. Apparent conductivity maps helped determine the salinization extent and identify salinity sources and migration mechanisms. Both the stream-axis and gridded airborne EM surveys were effective approaches to investigate salinization and interaction between ground water and surface water in this small basin, but multifrequency stream-axis images are a more practical alternative in larger basins where discrete salinity sources are poorly known.
Zooplankton respiration and its relation to plankton dynamics in two lakes of contrasting trophic state1

The seasonal cycles of respiration of net zooplankton and microplankton were determined for euphotic zones of Lake Washington and Findley Lake. In Lake Washington net zooplankton respiration rates estimated from ETS activity ranged from 22.4 to 1194 mg O.m/sup -2/.d/sup -1/ with the maximum occurring during the spring bloom. Net zooplankton respiration rates in Findley Lake ranged from 27 mg O.m/sup -2/.d/sup -1/ under ice cover to a maximum of 205 mg O.m/sup -2/.d/sup -1/, which occurred well after the bloom. Respiration rates estimated from ETS activity agreed well with those estimated from zooplankton species abundance. Zooplankton community respiration never exceeded 60% of primary production in Lake Washington; however, in Findley Lake zooplankton community respiration rates exceeded primary production during the latter part of the ice-free growing season. Phosphorus regeneration rates calculated from zooplankton respiration appeared sufficient to supply most of the phytoplankton phosphorus requirements during summer stratification in Lake Washington.
A temporal fixpoint calculus

Two distinct extensions of temporal logic has been recently advocated in the literature. The first extension is the addition of fixpoint operators that enable the logic to make assertions about arbitrary regular events. The second extension is the addition of past temporal connectives that enables the logic to refer directly to the history of the computation. Both extensions are motivated by the desire to adapt temporal logic to modular, i.e., compositional, verification (as opposed to global verification). We introduce and study here the logic mTL, which is the extension of temporal logic by fixpoint operators and past temporal connectives. We extend the automata-theoretic paradigm to mTL. That is, we show how, given an mTL formula
Accumulation and Preservation of Reworked Marine Pyrite Beneath an Oxygen-Rich Devonian Atmosphere: Constraints from Sulfur Isotopes and Framboid Textures

Abstract The Devonian Appalachian Basin provides a unique window to the unusual geochemical conditions required to form and preserve detrital metal sulfide deposits during the oxygen-rich Phanerozoic Eon. The Devonian Leicester Pyrite Member, a marine transgressive lag, occurs in the northern Appalachian Basin of western New York and is a reworked and redeposited acid-resistant residuum dominated by a wide range of pyritic clasts in the absence of carbonate grains. These iron sulfide grains include 10−2 m nodules, framboids, and pyritized fossil material (e.g., cephalopods, burrows, and steinkerns). A previous model for the formation of the Leicester Pyrite Member requires establishment of a strong and persistent density and chemical stratification in the Appalachian Basin. Although this model permits erosion under the low-oxygen conditions required for pyrite preservation, little geochemical evidence has been provided in corroboration, and the chemical conditions responsible for the formation, deposition, and preservation of the pyrite lag have remained speculative. Using a combined geochemical and petrographic approach focusing on the pyritic fraction and emphasizing sulfur isotopes and pyrite framboid size distributions, the specific redox conditions responsible for the formation of the Leicester Pyrite Member are addressed. The wide ranges of textural and isotopic data observed for the Leicester Pyrite Member, with δ34S values that range from −22 to +54% at a single location, are consistent with the general idea of lag concentration of pyritic debris formed under diverse diagenetic and possibly water-column (syngenetic) conditions. Energy propagation, possibly storm related, along the redox transition of the pycnocline and chemocline would have favored pyrite preservation, while still permitting enough oxidation and concomitant acid production to dissolve associated hydrodynamically equivalent carbonate debris. Intermittence in the stability of water-column stratification would have enhanced this oxidation, although an association with the overall oxygen deficiency that characterized the deposition of the overlying Geneseo Shale Member is demonstrated by the occurrence of microlaminated, Geneseo Shale Member-like clasts within the Leicester Pyrite Member. Our geochemical results confirm that during times of atmospheric oxygenation, pyrite reworking and lag formation require high-energy but low-oxygen conditions at pycnocline depths in a subaqueous marine setting. While not unique to the Leicester Pyrite Member, the specific sets of environmental conditions required for pyrite preservation differ from those of the fluvial settings in which Archean detrital pyrite and uraninite deposits formed. We suggest, therefore, that the presence of Phanerozoic pyrite lags such as the Leicester Pyrite Member does not compromise the utility of Archean detrital pyrite as a paleoredox proxy delineating early deficiency of atmospheric oxygen.
The p160 family coactivators regulate breast cancer cell proliferation and invasion through autocrine/paracrine activity of SDF-1α/CXCL12

Estrogen receptors (ERs) regulate the transcription of genes involved in breast cancer cell proliferation, invasion and metastasis. In addition to ligand concentration, phosphorylation and coactivator/corepressor levels control ER-dependent transcription. In this study, we used MCF-7 breast cancer sublines with variable levels of the steroid receptor coactivator 1 (SRC-1) to investigate the importance of coactivator levels in basal and estrogen-inducible expression of SDF-1alpha/CXCL12, cathepsin D and cMyc. Basal expression of SDF-1alpha and cMyc but not of cathepsin D was substantially lower in a MCF-7 subline lacking SRC-1 ((MCF-7/p2) compared with MCF-7 sublines expressing SRC-1 (MCF-7/p1 and LCC2). Although estrogen efficiently induced SDF-1alpha in MCF-7/p1 cells, very little induction of this gene was observed in MCF-7/p2 cells. The absence of SRC-1 had no effect on estrogen-inducible expression cMyc and cathepsin D suggesting that coactivator levels determine the expression of only a subset of estrogen-regulated genes. Introduction of SRC-1, SRC-2/TIF-2 or SRC-3/AIB1 increased basal expression of SDF-1alpha in MCF-7/p2 cells. Consistent with the role of SDF-1alpha in mediating estrogen-induced proliferation, estrogen failed to increase proliferation of MCF-7/p2 cells. In matrigel invasion assays, conditioned media from MCF-7/p1 but not MCF-7/p2 cells increased invasion of cancer cells expressing metastasis-associated genes and CXCR4, the receptor for SDF-1alpha. These results suggest that coactivators control SDF-1alpha expression, which mediates estrogen-induced proliferation and invasion through autocrine and paracrine mechanisms, respectively. These results also provide a molecular explanation for recent observations linking co-overexpression of coactivators and her2/neu with poor prognosis: coactivators increase SDF-1alpha expression whereas her2/neu stabilize CXCR4 protein.
On-the-fly detection of data races for programs with nested fork-join parallelism

Detecting data races in shared-memory parallel programs is an important debugging problem. This paper presents a new protocol for run-time detection of data races in ex­ ecutions of shared-memory programs with nested fork-join parallelism and no other inter-thread synch ronization. This protocol has signifi cantly smaller worst-case run-time over­ head than previous techniques. The worst-case space re­ quired by our protocol when monitoring an execution of a program P is O(V N), where V is the number of shared variables in P, and N is the maximum dynamic nesting of parallel constructs in P's execution. The worst-case time required to perform any monitoring operation is O(N). We formally prove that our new protocol always reports a non­ empty subset of the data races in a monitored program ex­ ecution and describe how this property leads to an effective debugging strategy.