cssi/SciSciGPT-SciSciNet huggingface dataset:
Fuzzy Petri Nets and Applications

Networks for information flow were invented in the dissertation of C.A. Petri (1961) xc21 at the University of Bonn. A. W. Holt and F. Commoner (1970, (xc9) extended them and called them Petri nets. Peterson (1981, xc20) and Reisig (1985, (xc23) provide treatises and the theory of Petri nets, that are used nowadays to model flows such as parts and materials in manufacturing processes (Zhou and Leu, 1991 (xc32), and logical truths in machine reasoning systems (Looney, 1988, xc15, and Murata et al, 1991 xc19).
A Majorant Approach to Robust Stability and Time-Domain Performance Analysis for Discrete-Time Systems

Majorant bounding techniques which appear in the work of Dahlquist and several researchers in large-scale systems analysis have recently been applied to develop robust stability and performance results for linear time-invariant systems with structured uncertainty. Previous results in majorant robustness analysis allow the performance to be measured in terms of the steady state variances of selected variables and in terms of the frequency-dependent behavior of the systems outputs. This paper considers linear discrete-time systems and measures performance in terms of the time-dependent behavior of the system outputs. For this class of systems majorant bounding techniques are used to develop robust performance bounds and sufficient conditions for robust stability.
New Potentials for Data-Driven Intelligent Tutoring System Development and Optimization

Increasing widespread use of educational technologies is producing vast amounts of data. Such data can be used to help advance our understanding of student learning and enable more intelligent, interactive, engaging, and effective education. In this article, we discuss the status and prospects of this new and powerful opportunity for data-driven development and optimization of educational technologies, focusing on intelligent tutoring systems We provide examples of use of a variety of techniques to develop or optimize the select, evaluate, suggest, and update functions of intelligent tutors, including probabilistic grammar learning, rule induction, Markov decision process, classification, and integrations of symbolic search and statistical inference.
Modulation of antiviral activity of interferon and 2',5'-oligoadenylate synthetase gene expression by mild hyperthermia (39.5 °C) in cultured human cells

Abstract The antiviral/antiproliferative/antitumor properties of interferon (IFN) are potentiated by a febrile temperature (Heron, I., and Berg, K. (1978) Nature 274, 508-510; Fleischmann, W. R., Fleischmann, C. M., Jr., and Gindhart, T. D. (1986) Cancer Res. 46, 1722-1726; Groveman, D. S., Borden, E. C., Merritt, J. A., Robins, H. I., Steeves, R., and Bryan, G. T. (1984) Cancer Res. 44, 5517-5521). To investigate the role of 2',5'-oligoadenylate (2-5A) synthetase in linking temperature with these biological functions of IFN, antiviral activities and expression of the 2-5A synthetase gene were measured simultaneously in control and type I IFN-treated HL-60 and WISH cells at the selected elevated temperature of 39.5 degrees C +/- 0.5 degrees C (herein referred to as hyperthermia). In both cell lines, the IFN-mediated antiviral effect was enhanced 3-10-fold. Concurrently, enzymatic assays and immunoblot analyses with an anti-40-kDa synthetase antibody clearly gave a 2-3-fold increase of synthetase above that observed at the normal cell culture temperature (37 degrees C). These results suggest that potentiation of 2-5A synthetase must partially account for the enhanced antiviral activity of IFN at the higher cell culture temperature. The supranormal elevation of 2-5A synthetase was accompanied by a parallel increase in the steady-state concentration of 2-5A synthetase mRNA, which is likely to contribute to the observed increase in enzyme level. Transient reporter gene expression studies using plasmid constructs carrying 2-5A synthetase gene promoter linked in tandem with chloramphenicol acetyltransferase showed that IFN-inducible chloramphenicol acetyltransferase activity was not influenced by hyperthermia, suggesting that transcription activation is an unlikely explanation for the observed 2-5A synthetase mRNA level increases. Messenger RNA stability assays showed that the half-life (t1/2) of 2-5A synthetase mRNA was extended from 2 to 4 h at 39.5 degrees C. Under identical conditions, the t1/2 of poly(A)+ RNA remained unchanged whereas the t1/2 of beta-actin mRNA was reduced. Taken together, these results are consistent with the interpretation that selective stabilization of 2-5A synthetase mRNA at the elevated temperature is a major factor contributing to the potentiation of antiviral activity of IFN by hyperthermia.
A language for distributed applications

Durra is a language designed to support the development of distributed applications consisting of multiple, concurrent, large-grained tasks executing in a heterogeneous network. An application-level program is written in Durra as a set of task descriptions that prescribes a way to manage the resources of a heterogeneous machine network. The application describes the tasks to be instantiated and executed as concurrent processes, the intermediate queues required to store the messages as they move from producer to consumer processes, and the possible dynamic reconfigurations of the application. The application-level programming paradigm fits a top-down, incremental method of software development very naturally. It is suggested that a language like Durra would be of great value in the development of large, distributed systems. >
Understanding the Pathobiology of Pulmonary Vascular Disease

Pulmonary arterial hypertension (PAH) is a panvasculopathy that results in a progressive increase in pulmonary arterial pressure in association with variable degrees of pulmonary vascular remodeling, vasoconstriction, and in situ thrombosis. This leads to concentric obliteration of the pulmonary arteriole and the development of plexiform lesions that in turn result in an increased pulmonary vascular resistance and eventual right heart failure and death. The complex pathological features of pulmonary arterial hypertension (PAH) are highlighted in this review. A greater understanding of this complex pathobiology of PAH is essential for the future development of new therapeutic options.
A Voluntary Environmental Classification System for Pharmaceutical Substances

As a consequence of increasing interest in the area of pharmaceuticals in the environment, the Swedish Association of the Pharmaceutical Industry has in collaboration with a range of stakeholders developed an environmental classification scheme for active pharmaceutical ingredients. This article describes the background of the system, its design, and future development.
I'll have what she's having: the impact of model characteristics on children's food choices.

This research investigates children’s use of social categories in their food selection. Across three studies, we presented preschoolers with sets of photographs that contrasted food-eating models with different characteristics, including model gender, race (Black, White), age (child or adult), and ⁄ or expression (acceptance or rejection of the food). Children were asked to pick between the photographs to choose which food they would like for snack. Results demonstrated that preschoolers prefer foods being eaten by models with positive over negative expressions, foods being eaten by child over adult models, and foods being eaten by child models of the same gender as themselves over models of the other gender. This work connects with previous research on children’s understanding of social categories and also has important practical implications for how characteristics of a foodeating model can affect children’s willingness to try new foods.
Detection and Characterization of Damage in Composite Plates Using Shearography and Wave-Based Acoustic Emission Techniques

This paper investigates the use of shearography and waveform- based acoustic emission (AE) techniques to detect and assess damage in composite plates due to high velocity impact. Five 48-ply [0/+45/90/-45]6s laminated AS4/PEEK composite plates donated by Boeing Company in St. Louis were used as test specimens. Shearography images of all five test specimens were taken before impact testing to detect any pre- existing internal damage from fabrication. Three broadband AE sensors were mounted on the surface of the composite plates to measure AE signals due to impact. High velocity impact tests of plates with all four edges clamped were conducted using a gas gun facility. The AE sensor signals were instantaneously acquired during the impact tests and stored in a Pentium computer. The digitized AE signals were processed in time and frequency domains. The raw AE signals were preprocessed to remove reflections from the plate boundaries that distort the wave form and cause errors. The resulting damage due to impact was evaluated using shearography fringe patterns and AE sensor signal features. The results show a correlation of AE parameters such as AE energy, AE amplitude, AE count, and shearography fringe patterns with impact energy and impact damage of the composite plates. The AE signals show the presence of both extensional and flexural wave modes with flexural wave the dominant mode. There is quite a distinctive difference between shearography fringe patterns of undamaged and damaged composite plates.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Tumor Necrosis Factor-α-induced Targeted Proteolysis of Cystathionine औ-Synthase Modulates Redox Homeostasis *

Cystathionine beta-synthase (CBS) catalyzes the first of two steps in the transsulfuration pathway that converts homocysteine to cysteine, a precursor of glutathione, a major intracellular antioxidant. Tumor necrosis factor-alpha (TNFalpha), which is known to enhance production of reactive oxygen species, increased CBS activity and glutathione levels in HepG2 cells. Western blot analysis revealed that the higher CBS activity correlated with cleavage of the enzyme to a truncated form. This cleavage was suppressed by inhibitors of superoxide production or by transfection with an expression vector for manganese superoxide dismutase. The commonly used proteasome inhibitors, MG132 and lactacystin but not N-acetyl-Leu-Leu-norleucinal, suppressed the TNFalpha-induced response. Targeted proteolysis of CBS was also observed in livers of mice injected with lipopolysaccharide, which is known to induce TNFalpha. Together, these data reveal a novel and previously unknown mechanism of regulation for homocysteine-linked glutathione homeostasis in cells challenged by oxidative stress.
INVESTIGATION OF THE USE OF MAGNESIUM ALUMINATE (SPINEL) AS A MATERIAL FOR GLASSMELTING CONTAINERS

Crucibles were formed from spinel raw materials and commercial spinel grains, with and without admixtures of other chemicals. Bottle glass was melted in these and the behavior was compared with similar containers made from fueclay grog and mullite (Corhart). The tests consisted of heating bottle glass in the crucibles at 1400°C for four hours and noting the appearance of the crucibles after the treatment. The results indicated that. under the conditions used, magnesia spinel is not suited for glass refractory material.
Effects of Purified Polybrominated Biphenyl Congeners on the Thyroid and Pituitary Glands in Rats

Young male rats were fed diets containing 0, 1, 10, or 100 ppm of Firemaster (FM) BP-6 for 30 days and thyroidal and hypophyseal effects were compared with those caused by feeding identical amounts...
Abnormal beam-profile behavior in the Nd:YAG ceramic regenerative amplifier

The output beam profile of a Nd:YAG diode-pumped ceramic regenerative amplifier depends heavily on amplified spontaneous emission (ASE) and amplification competition. A careful pump geometry arrangement is required in a highgain regenerative amplifier to achieve the beam profile that corresponds to the TEM 00 mode of the amplifier cavity.
Sex-linked mutations in Drosophila after exposure to various mixtures of gas atmospheres

Abstract Drosophila melanogaster males, Canton-Special strain, were exposed to six different gas atmospheres, to determine the sex-linked recessive lethal mutation rate utilizing the Basc technique ( Muller and Oster, 1963 ). All of these gases were significantly mutagenic to Drosophila . One of the gases, perfluorobutene-2 was studied in mixtures with compressed air, carbon dioxide, oxygen, or nitrogen to determine its effects in combination with various components of air. A gas-mixing device for exposing Drosophila was constructed for the monitoring and mixing of the gases studied. Treatment with perfluorobutene-2 produced a recessive mutation rate of 1.78% as compared to 0.25% for compressed air. This was higher than any mutation rate obtained when perfluorobutene-2 was mixed with oxygen, nitrogen, carbon dioxide, or compressed air. The quantity of perfluorobutene-2 present in the mixture was the principal factor in contributing to a high mutation rate.
Constraints to curriculum reform: Teachers and the myths of schooling

Curriculum reform efforts usually have ignored the culture in which curriculum is embedded. Principal components of the culture are the knowledge of teachers and the myths of this culture. Images, metaphors, and metonymies are forms of teacher knowledge that influence the manner in which teachers define their roles and implement the curriculum. Unless endeavors are made to facilitate teacher learning through the construction of new images, metaphors, and metonymies, it is unlikely that curricular reform will proceed in the intended manner. Similarly, the myths that define the customs and taboos of a culture need to be considered by instructional designers if their curricular resources are to be used as intended. The myths ofteacher as controller of students andobjectivism together might persuade teachers to adhere to the more traditional approach whereby knowledge is transferred to students in teacher-controlled activities. This article describes theScience Vision series, a hypermedia system developed in response to a clear need for additional resources to educate teachers concerning alternative myths and their use in relation to utilizing resources.
How much is a health insurer willing to pay for colorectal cancer screening tests

Colorectal Cancer (CRC) screening tests have proven to be cost-effective in preventing cancer incidence. Yet, as recent studies have shown, CRC screening tests are noticeably underutilized. Among the factors influencing CRC screening test utilization, the role of health insurers has gained considerable attention in recent studies. In this paper, we propose an analytical model for the market of CRC screening tests and show how the insurer can benefit from a computer simulation model to cope with the problem of incomplete and asymmetric information inherent in this market. Our estimates reveal that promoting CRC screening tests is not necessarily economically attractive to the insurer, unless the insurer?s valuation of life is greater than a certain limit. We use the proposed model to estimate such a threshold - the insurer?s willingness-to-pay to acquire one additional life year by covering the CRC screening tests.
Process Tolerant ß-ratio Modulation for Ultra-Dynamic Voltage Scaling

Most wireless and hand-held gadgets work in burst mode, and the performance demand varies with time. When the performance requirement is low, the supply voltage can be dithered and the circuit can enter from superthreshold region to subthreshold region (Vdd < VT). Such ultra dynamic voltage scaling (UDVS), where the supply voltage switches from 1.2V to 200mV (say), enables remarkable decrease in power consumption with "acceptable" performance penalty in the non-burst mode of operation. However, subthreshold operation is very sensitive to process variation (PV) due to the reduced noise margin, and may not work properly unless corrective measures are taken. In this paper, the authors model the trip voltage in both subthreshold and superthreshold regions, and analyze the impact of PV in UDVS. They also propose a circuit design technique such that the same logic gate can efficiently operate in both superthreshold and subthreshold regions under PV. The authors do that by modulating the beta-ratio (P-to-N ratio) of the logic gates. By proper beta-ratio modulation, the authors show that the proposed methodologies can lower energy dissipation per cycle by more than an order of magnitude (42times) in non-burst mode with reduced impact to PVs
Deposition and phagocytosis of inhaled particles in the gas exchange region of the duck, Anas platyrhynchos.

Abstract Little is known about the fate of inhaled aerosol particles in birds; even the anatomical location of phagocytic cells within the lungs has yet to be clearly demonstrated. We exposed 2 anesthetized, spontaneously breathing ducks to a non-toxic iron oxide aerosol (aerodynamic mass mean diameter = 0.18 μm 460mg/m3) for 1.75h and 2 awake, resting ducks to less concentrated aerosol (38mg/m3) for 6 h two consecutive days. All 4 ducks were sacrificed 24 h after the end of the last exposure. Their lungs, as well as the lungs from a control duck not exposed to the aerosol, were fixed in situ by insufflation of osmium tetroxide vapor or by intravascular perfusion. Then samples of the gas exchange region were examined with a transmission electron microscope. We found iron oxide particles: (1) trapped within the trilaminar substance that is unique to avian lungs and coats the atria and infundibula; (2) within epithelial cells of the atria and initial portions of the infundibula; and (3) within interstitial macrophages. Only occasionally, small amounts of particles were found in the air capillaries. We conclude that both epithelial cells and interstitial macrophages can phagocytize particles in avian lungs, and that there is some convective transport of aerosol to the atria and the initial portions of the infundibula.
Development of the Interplay Between Automatic Processes and Cognitive Resources in Reading

An account was tested of the development of the interplay between automatic processes and cognitive resources in reading. According to compensatory-encoding theory, with advancing skill, readers increasingly keep automatic processes from faltering and provide timely, accurate data to working memory by pausing, looking back, rereading, and compensating in other ways when automatic processes fail. Reading skill profiles (e.g., word naming, semantic access, working memory capacity) were obtained from 71 third graders, 68 fifth graders, and 72 seventh graders from a university lab school or a public school (ages 7 to 15; 146 Caucasians, 61 African Americans, 2 Native Americans, 2 Latino Americans). Children participated in an unrestricted reading task (no time or performance pressure) and were randomly assigned to 1 of 2 levels of 3 experimental manipulations of restriction on reading: time pressure or no pressure, constant reading rate or variable reading rate, read silently or read aloud. Regression analyses revealed that developmental level and restriction moderated the reading skill level-comprehension relationship, and restriction lowered comprehension when it overwhelmed skills, especially for younger readers. Verbally inefficient readers compensated most often, and older readers compensated most efficiently.
Electrocardiographic, arteriographie and ventriculographic correlations in transmural myocardial infarction

Abstract To determine if significant interrelations exist between the electrocardiographic diagnosis of transmural myocardial infarction, sites of coronary arterial obstruction, and left ventricular asynergy, 235 patients with angiographically documented coronary artery disease were subdivided according to the electrocardiographic location of the myocardial infarction, the coronary arterial system involved and the site of ventricular asynergy. Of 82 instances of anterior myocardial infarction, the left anterior descending artery demonstrated significant disease in 79 (96 percent). Of 100 instances of inferior myocardial infarction, the right coronary artery was significantly diseased in 87 and the left circumflex in 55. When multiple infarctions were present, multivessel disease was found in 93 percent of patients. Left ventricular asynergy was present in 81 percent, including 84 percent of those with anterior infarction, 74 percent of those with inferior infarction, and 93 percent of those with multiple infarctions. The results of our study suggest that the electrocardiogram is often of value in indicating sites of coronary arterial obstruction and ventricular asynergy in patients with coronary artery disease and transmural myocardial infarction.
Long-range proximity effect in aluminum thin films with regions of nearly identical transition temperatures.

We have investigated the resistive transition of dirty aluminum thin films whose transition temperature is spatially modulated by \ensuremath{\sim}2--4 % along the current path. At current densities as high as 600 A/${\mathrm{cm}}^{2}$, the system exhibits a single homogeneous transition for modulation lengths up to 50 \ensuremath{\mu}m, an order of magnitude longer than predicted by current theories. In the limit that the modulation length is 50 \ensuremath{\mu}m, the ${\mathit{T}}_{\mathit{c}}$ depends sensitively and monotonically on the ratio of the lengths of the etched and the unetched regions (${\mathit{d}}_{1}$/${\mathit{d}}_{2}$), but only weakly on their absolute magnitudes. This behavior is reproduced for ${\mathit{T}}_{\mathit{c}}$ modulation parallel or perpendicular to the current flow. For samples with a controlled aperiodic (Fibonacci) modulation, the ${\mathit{T}}_{\mathit{c}}$ is compatible with that of periodically modulated films. The dependence of the ${\mathit{T}}_{\mathit{c}}$ on ${\mathit{d}}_{1}$/${\mathit{d}}_{2}$ can be fitted to a simple Ginzburg-Landau theory which assumes that the effective pair coherence length is long in comparison with the modulation period. Despite the good fit, data for the full range of experimentally accessible modulation length scales are not consistent with a more detailed microscopic theory. We believe this long-range proximity effect is not the consequence of pair tunneling, but is a manifestation of the long distance over which quasiparticle phase coherence is maintained in a two-dimensional metal film.
Dopamine D1-like receptor activation depolarizes medium spiny neurons of the mouse nucleus accumbens by inhibiting inwardly rectifying K+ currents through a cAMP-dependent protein kinase A-independent mechanism

Dopamine/cAMP signaling has been reported to mediate behavioral responses related to drug addiction. It also modulates the plasticity and firing properties of medium spiny neurons (MSNs) in the nucleus accumbens (NAc), although the effects of cAMP signaling on the resting membrane potential (RMP) of MSNs has not been specifically defined. In this study, activation of dopamine D1-like receptors (D1Rs) by SKF-38393 elicited membrane depolarization and inward currents in MSNs from the NAc core of 14-17 day-old mice. Similar results were obtained following stimulation of adenylyl cyclase (AC) activity with forskolin or application of exogenous cAMP. Forskolin occluded SKF-38393's effects, thus indicating that D1R action is mediated by AC/cAMP signaling. Accordingly, AC blockade by SQ22536 significantly inhibited the responses to SKF-38393. Effects elicited by D1R stimulation or increased cAMP levels were unaffected by protein kinase A (PKA) or protein kinase C (PKC) blockade and were not mimicked by the Epac agonist, 8CPT-2Me-cAMP. Responses to forskolin were also not significantly modified by cyclic nucleotide-gated (CNG) channel blockade. Forskolin-induced membrane depolarization was associated with increased membrane input resistance. Voltage-clamp experiments revealed that forskolin and SKF-38393 effects were due to inhibition of resting K(+) currents exhibiting inward rectification at hyperpolarized potentials and a reversal potential (around -90 mV) that shifted with the extracellular K(+) concentration. Forskolin and D1R agonist effects were abolished by the inward rectifier K(+) (Kir)-channel blocker, BaCl(2). Collectively, these data suggest that stimulation of postsynaptic D1Rs in MSNs of the NAc core causes membrane depolarization by inhibiting Kir currents. This effect is mediated by AC/cAMP signaling but it is independent on PKA, PKC, Epac and CNG channel activation, suggesting that it may stem from cAMP's direct interaction with Kir channels. D1R/cAMP-mediated excitatory effects may influence the generation of output signals from MSNs by facilitating their transition from the quiescent down-state to the functionally active up-state.
Condom-related problems among a racially diverse sample of young men who have sex with men

We described frequencies of condom-related problems in a racially diverse sample of young men who have sex with men (YMSM), and tested these condom-related problems as an explanation for racial disparities in HIV rates among YMSM. Participants were 119 YMSM from a longitudinal study of sexual minority health behaviors. Almost all participants (95.4%) experienced at least one condom error. On average, African American and non-African American YMSM experienced the same number of recent condom-related problems. Therefore, differences in condom-related problems are unlikely to explain racial disparities in HIV rates among YMSM. When serving YMSM, providers should both promote condom use and explain steps to correct condom use.
A useful method for converting 2° alcohols to their chlorides with retention of configuration

Abstract Xanthate esters of 2° alcohols are converted to their chlorides with retention of configuration in good yield by use of sulfuryl chloride.
Mechanisms of Three-Dimensional Tumor Cell Motility in Dense Extracellular Matrices

Tumor cell invasion requires navigation of tissue barriers of varying architecture. For instance, the extreme invasiveness of glioma cells is facilitated by their ability to migrate diffusely through brain parenchyma and approach guidance tracks along blood vessels. Brain parenchyma has a distinct physical structure characterized by densely packed neural cell processes and sub-micron extracellular space, and is largely devoid of the fibrillar collagen scaffolding typically found in stromal tissue. Consequently, glioma cells migrating in brain slices exhibit a distinct type of motility, with branched protrusions and hourglass-shaped cell-body deformations that help squeeze cells through tight spaces (Beadle et al., Mol. Biol. Cell 2008; 19(8):3357-68). However, the mechanistic details of this unique mode of motility remain incompletely understood. To address this question, we synthesized brain-mimetic nanoporous, non-fibrillar extracellular matrices (ECMs) based on cross-linked hyaluronic acid (HA), and verified that three-dimensional glioma cell motility in these ECMs strikingly recapitulated the phenotype seen in brain slices (Ananthanarayanan et al. Biomaterials 2011; 32(31):7913-23). Eliminating RGD peptides from the ECM abolished invasion, suggesting a requirement for integrin-mediated adhesions for this mode of motility. Increasing matrix density, or inhibiting myosin-based cellular contractility by blebbistatin or shRNA-induced knockdown of Myosin IIA severely impaired motility. We report preliminary results from two sets of studies: First, we investigate the balance of protrusive and contractile forces in glioma cell motility by pharmacologically and genetically manipulating the Rho GTPases RhoA, Rac1, and Cdc42. Second, we explore the involvement of actin-nucleating proteins such as Arp2/3 and formins in the protrusive dynamics observed in this mode of motility. Our studies help define the signaling mechanisms underlying the distinctive glioma cell motility observed in dense matrices.
Dichroism in Essentially Pure and Activated Cadmium Sulfide Single Crystals

Dichroism is observed in CdS, CdS:Cu, CdS:Mn, CdS:In, and CdS:O single crystals. The activated crystals contain 0.1% of activator except in the case of oxygen activator which is ∼1%. Inversion of the crystal sign, i.e., positive to negative, is observed in CdS crystals at 5245 A. In the case of activated crystals, the inversion point was obtained by extrapolation and found to coincide with that of the “pure” CdS crystal. A simplified method for measuring indexes of refraction over a wide range has also beed devised.
Nonmetric multidimensional scaling: Recovery of metric information

The degree of metric determinancy afforded by nonmetric multidimensional scaling was investigated as a function of the number of points being scaled, the true dimensionality of the data being scaled, and the amount of error contained in the data being scaled. It was found 1) that if the ratio of the degrees of freedom of the data to that of the coordinates is sufficiently large then metric information is recovered even when random error is present; and 2) when the number of points being scaled increases the stress of the solution increases even though the degree of metric determinacy increases.
Stabilization of the Conductive Conformation of a Voltage-gated K+ (Kv) Channel THE LID MECHANISM

Voltage-gated K(+) (Kv) channels are molecular switches that sense membrane potential and in response open to allow K(+) ions to diffuse out of the cell. In these proteins, sensor and pore belong to two distinct structural modules. We previously showed that the pore module alone is a robust yet dynamic structural unit in lipid membranes and that it senses potential and gates open to conduct K(+) with unchanged fidelity. The implication is that the voltage sensitivity of K(+) channels is not solely encoded in the sensor. Given that the coupling between sensor and pore remains elusive, we asked whether it is then possible to convert a pore module characterized by brief openings into a conductor with a prolonged lifetime in the open state. The strategy involves selected probes targeted to the filter gate of the channel aiming to modulate the probability of the channel being open assayed by single channel recordings from the sensorless pore module reconstituted in lipid bilayers. Here we show that the premature closing of the pore is bypassed by association of the filter gate with two novel open conformation stabilizers: an antidepressant and a peptide toxin known to act selectively on Kv channels. Such stabilization of the conductive conformation of the channel is faithfully mimicked by the covalent attachment of fluorescein at a cysteine residue selectively introduced near the filter gate. This modulation prolongs the occupancy of permeant ions at the gate. It is this longer embrace between ion and gate that we conjecture underlies the observed stabilization of the conductive conformation. This study provides a new way of thinking about gating.
Liver transplantation in cystic fibrosis: a report from Baylor College of Medicine and the Texas Children's Hospital.

CF affects one of 2000 Caucasians, and approximately 25% are found to have CFLD for which OLT may be indicated. Timing of transplantation, contraindications, and survival are still widely debated. We report the outcomes of OLT for pediatric patients with CFLD from the largest children's hospital in the United States. Our records since September 1998 were analyzed for all patients undergoing OLT for CFLD. Nine patients were then compared to similar patients in the UNOS/OPTN database (n = 155). Survivals were calculated with the Kaplan-Meier method and compared using the log-rank test. All statistics were performed in SPSS 15.0. We performed OLT on nine pediatric patients with CFLD, with age ranging from nine to 17 yr at the time of transplant. Mean survival was 69.2 months; patient and allograft survivals at one and five yr were 88.9%, with one death at day 21 due to Aspergillus fumigatus sepsis. Two patients underwent concurrent multi-organ transplantation. One patient required double lung transplantation four yr after isolated OLT. Comparison to the UNOS/OPTN database revealed a trend toward improved survival. Patients with CF can achieve favorable outcomes after OLT, as we report excellent survivals for pediatric patients with CFLD.
A note on the incidence of pectoral alopecia

Pectoral alopecia was found to be present in 26 per cent of an average sampling of the male hospital population exclusive of hepatic and endocrine disease. However, this was observed to be far more frequent in the Negro than the white groups—46 and 16 per cent, respectively. The total incidence of pectoral alopecia in a group of 34 white and 6 Negro patients with cirrhosis was only 20 per cent. In every instance alopecia had always been present and antedated the liver disease.
Analysis of sulfur–iodine thermochemical cycle for solar hydrogen production. Part I: decomposition of sulfuric acid

The sulfur–iodine (S–I) thermochemical water splitting cycle is one of the most studied cycles for hydrogen (H2) production. S–I cycle consists of four sections: (I) acid production and separation and oxygen purification, (II) sulfuric acid concentration and decomposition, (III) hydroiodic acid (HI) concentration, and (IV) HI decomposition and H2 purification. Section II of the cycle is an endothermic reaction driven by the heat input from a high temperature source. Analysis of the S–I cycle in the past thirty years have been focused mostly on the utilization of nuclear power as the high temperature heat source for the sulfuric acid decomposition step. Thermodynamic as well as kinetic considerations indicate that both the extent and rate of sulfuric acid decomposition can be improved at very high temperatures (in excess of 1000 °C) available only from solar concentrators. The beneficial effect of high temperature solar heat for decomposition of sulfuric acid in the S–I cycle is described in this paper. We used Aspen Technologies' HYSYS chemical process simulator (CPS) to develop flowsheets for sulfuric acid (H2SO4) decomposition that include all mass and heat balances. Based on the HYSYS analyses, two new process flowsheets were developed. These new sulfuric acid decomposition processes are simpler and more stable than previous processes and yield higher conversion efficiencies for the sulfuric acid decomposition and sulfur dioxide and oxygen formation.
Sulfur and organic carbon contents in sediment cores from the Tyro and Orca basins

Abstract The Tyro and Orca basins are two small, deep-water, euxinic depressions in the Eastern Mediterranean and the northern Gulf of Mexico, respectively. Anoxic bottom waters are known to be nearly saturated with NaCl. Sediment accumulation in the basins has been complicated by episodic slumping and/or redeposition. Analyses of sediment total reduced sulfur and organic carbon and resulting S C ratios are used to test the feasibility of using these parameters as indicators for the mode of sediment deposition in the basins. Sediments originally deposited in the basin are, as expected, enriched in sulfur and carbon content as compared to sediments that originated from areas beyond the limit of the anoxic brine pool and were redeposited later inside the basin. However, values of the S C ratios of these primarily deposited sediments are less than those of sediments of redeposited origin, and indicate a low rate of sulfide conversion during bacterial sulfate reduction. This inconsistency is interpreted to be due to the high-salinity basin waters inhibiting the overall activity of sulfate reducers and their associated heterotrophic microorganism communities and/or the reactivity of initially deposited organic matter. This study also demonstrates that variations of sulfur and carbon contents and their S C ratios together can be used as a geochemical tool to delineate the origin of sediments accumulated in hypersaline euxinic basins. However, the feasibility of the S C method requires a further check as to whether the rate of sulfate reduction could have been constrained, even in environments of normal salinity.
Measurements of 35S in the marine boundary layer at La Jolla, California: A new technique for tracing air mass mixing during Santa Ana events

[1] 35S (t1/2 = ∼87 days) is a radioactive isotope that is naturally produced in the upper atmosphere by the interaction of cosmic rays with 40Ar. In the atmosphere, 35S oxidizes to 35SO2, which further oxidizes to 35SO42− depending on the oxidative rates. Here, we report measurements of 35S activity in both 35SO2 (gas) and 35SO42− (aerosol) (coarse, >1.5 μm; and fine, <1.5 μm size fraction) collected during 2009–2010 at La Jolla, California, and we demonstrate that 35S is a unique tracer for understanding air mass mixing and boundary layer dynamics. The annual mean 35SO2 concentration is 71 ± 61 (mean ± 1σ) atoms/m3. The annual mean 35SO42− abundance in the fine fraction (455 ± 157 atoms/m3) is higher than in the coarse fraction (136 ± 59 atoms/m3). This is most probably a consequence of the fine sulfate aerosol fraction being produced by gas phase oxidation of 35SO2, whereas the coarse fraction is mainly derived from oceanic sea salt sulfate. 35S activity in coarse sulfate is mainly due to uptake of 35SO2 and subsequent oxidation on sea salt aerosols. 35SO2 and 35SO42−activities were observed to be higher during stratospheric-tropospheric mixing and Santa Ana wind events that provide high-altitude air mass mixing into the marine boundary layer. A model calculation shows that a maximum of 41% of total air sampled in the marine boundary layer recently originated from the free troposphere and mixed into the marine boundary layer during Santa Ana wind events. This work is the first to quantify and explain air mass mixing during Santa Ana events using35S activity.
Biogenic nanoporous silica-based sensor for enhanced electrochemical detection of cardiovascular biomarkers proteins

The goal of our research is to demonstrate the feasibility of employing biogenic nanoporous silica as a key component in developing a biosensor platform for rapid label-free electrochemical detection of cardiovascular biomarkers from pure and commercial human serum samples with high sensitivity and selectivity. The biosensor platform consists of a silicon chip with an array of gold electrodes forming multiple sensor sites and works on the principle of electrochemical impedance spectroscopy. Each sensor site is overlaid with a biogenic nanoporous silica membrane that forms a high density of nanowells on top of each electrode. When specific protein biomarkers: C-reactive protein (CRP) and myeloperoxidase (MPO) from a test sample bind to antibodies conjugated to the surface of the gold surface at the base of each nanowell, a perturbation of electrical double layer occurs resulting in a change in the impedance. The performance of the biogenic silica membrane biosensor was tested in comparison with nanoporous alumina membrane-based biosensor and plain metallic thin film biosensor. Significant enhancement in the sensitivity and selectivity was achieved with the biogenic silica biosensor, in comparison to the other two, for detecting the two protein biomarkers from both pure and commercial human serum samples. The sensitivity of the biogenic silica biosensor is approximately 1 pg/ml and the linear dose response is observed over a large dynamic range from 1 pg/ml to 1 microg/ml. Based on its performance metrics, the biogenic silica biosensor has excellent potential for development as a point of care handheld electronic biosensor device for detection of protein biomarkers from clinical samples.
Rejuvenation of the aging thymus: growth hormone-mediated and ghrelin-mediated signaling pathways.

One of the major fundamental causes for the aging of the immune system is the structural and functional involution of the thymus, and the associated decline in de novo naive T-lymphocyte output. This loss of naive T-cell production weakens the ability of the adaptive immune system to respond to new antigenic stimuli and eventually leads to a peripheral T-cell bias to the memory phenotype. While the precise mechanisms responsible for age-associated thymic involution remain unknown, a variety of theories have been forwarded including the loss of expression of various growth factors and hormones that influence the lymphoid compartment and promote thymic function. Extensive studies examining two hormones, namely growth hormone (GH) and ghrelin (GRL), have demonstrated their contributions to thymus biology. In the current review, we discuss the literature supporting a role for these hormones in thymic physiology and age-associated thymic involution and their potential use in the restoration of thymic function in aged and immunocompromised individuals.
Extended heating of the nighttime D region by very low frequency transmitters

Very low frequency (VLF, 3–30 kHz) signals propagating in the Earth-ionosphere waveguide are used to probe the heated nighttime D region over three keyed U.S. Navy VLF transmitters. The keyed VLF transmitters are turned on-off in periodic formats for thirty to sixty minutes each day over the course of several months each, providing sensitive measurements of their heating effect on the surrounding ionosphere. On several occasions, the heating effect is observed on probe signal pathways at distances greater than 1500 km from the keyed transmitter. It is proposed that the heating effect of VLF transmitters extends over very large distances through the subionospheric propagation of its radiated signal. General statistics are presented on the observed extent of the heating region over the course of the experiments, and a combination of propagation, heating, and scattering models are used to analyze the results.
The inner structure of the dilogarithm in algebraic fields

Abstract A certain combination of dilogarithms of powers of an algebraic base is constructed and shown to have significant properties when the powers are divisors of the highest power (index) in the relation. The combination is called a ladder and under some circumstances is zero when all the coefficients involved are rational. When this happens it is found empirically that the base satisfies an equation of cyclotomic form whose structure is obtainable by inspection from the ladder. A proof of this equation is given for the case where the ladder is obtainable by a finite number of steps from Abel's functional equation. A number of conjectures are made and used to discover many new relations, all of which are confirmed numerically, but which do not appear to be capable of analytic proof with presently available methods. The paper concludes with some conjectures on the cyclotomic equations which occur in this context.
Peptide chain termination

In this, the third of our three-part series on protein synthesis, chain termination is reviewed. Termination differs markedly from initiation and elongation (reviewed in July and August TIBS) since the codon recognition molecules are proteins, not tRNA, and a perturbation of the peptidyltransferase leads to hydrolysis of the peptidyl-tRNA rather than the formation of peptide bonds.
An Assessment of Myers-Briggs Temperament Indicator Based Team Formation Strategies for One-Semester Design Projects

There has been some discussion in the literature concerning whether homogeneous or heterogeneous design teams produce the better results. This study compares the performances of three aspects of the design process as produced by 81 student teams. The teams are categorized by the Myers-Briggs Type Indicators of their members. The more personality homogeneous teams produced the better quality work. Hence, the study has added some support to the argument that homogeneous teams may be preferable, at least for relatively short projects. However, there are many factors besides similar of personalities, such as past academic performance, age, gender mix, ethnic mix, and work experience, that may affect team performance. Therefore it would be a mistake to assume that forming teams based on personality type alone will significantly and uniformly affect their performances.Copyright © 2006 by ASME
A visual thalamo-telencephalic pathway in a teleost fish (Holocentrus rufus)

Injections of large doses of horseradish peroxidase (HRP) into the telencephalon of the squirrel fish (Holocentrus rufus) revealed the first anatomical evidence for a visual thalamo-telencephalic projection in a teleost. The central optic nucleus of the thalamus appears to be the only visual thalamic nucleus projecting to the telencephalon in this species. Since the central optic nucleus has a large tectal input but not a direct one from the retina, it is suggested that a retino-geniculo-telencephalic pathway does not exist in this species.
Prehospital delay with myocardial infarction: the interactive effect of clinical symptoms and race.

This study examined prehospital delays and clinical symptoms of myocardial infarction (MI) in blacks and whites and the relationship between longer delays and types of clinical symptoms. The convenience sample included 128 patients, admitted consecutively, with acute MI. Data on types of clinical symptoms of MI and treatment-seeking behavior were collected on day 2 or 3 after admission, using face-to-face semistructured interviews. The total mean delay time differed significantly between blacks and whites (16 hours vs. 8.8 hours, p < .05). Although the frequency of chest pain was similar in both blacks and whites (78% vs. 77%), more than twice as many blacks as whites presented with symptoms of dyspnea (56% vs. 24%, p < .01) and fatigue (32% vs. 17%, p < .05). There was an interactive effect of race-ethnicity and types of symptoms on delay (p < .05) was present. Delay times for whites with chest pain were shorter than for whites without chest pain. Delay times for blacks with dyspnea were significantly shorter than for blacks without dyspnea, although delay times did not differ between whites with and without dyspnea.
Concordance of distinguishing electrocardiographic features during sinus rhythm with the location of accessory pathways in the Wolff-Parkinson-White syndrome

Knowledge of the location of accessory pathways in patients with Wolff-Parkinson-White (WPW) syndrome is pertinent to patient management. Despite the recognition that features of delta waves present during maximal preexcitation reflect ventricular activation at different sites around the anulus fibrosus, the value of electrocardiographic patterns observed during sinus rhythm, when ventricular preexcitation is often not maximal for identifying accessory pathway locations, has not been determined. In this study, 12-lead electrocardiograms recorded during sinus rhythm from 66 patients with WPW syndrome were analyzed for delta-wave polarity, QRS axis in the frontal plane, the pattern of precordial R-wave transition, and concordance between electrocardiographic patterns and the site of the accessory pathway determined using catheter and intraoperative computer mapping. Electrocardiograms from patients with left lateral sites showed negative delta waves in leads I or aVL, a normal QRS axis and early precordial R-wave transition (20 of 24 patients); left posterior sites manifested negative delta waves in II, III and aVF and a prominent R wave in V1 (14 of 16 patients); posteroseptal sites had negative delta waves in II, III and aVF, a superior QRS axis and an R less than S in V1 (all 16 patients); right free wall locations manifested negative delta waves in aVR, a normal QRS axis, and R-wave transition in V3-V5 (6 of 6 patients); and anterior septal sites had negative delta waves in V1 and V2, a normal QRS axis, and R-wave transition in V3-V5 (4 of 4 patients). Characteristic electrocardiographic patterns were not observed in 5 patients because of insufficient preexcitation. Each had a left lateral or left posterior pathway. Overall, the proposed electrocardiographic criteria derived during sinus rhythm identified correctly the accessory pathway location in 60 of 66 patients (91%). Thus, the electrocardiogram provides the physician with a reliable noninvasive means of regionalizing the location of accessory pathways in patients with WPW syndrome.