cssi/SciSciGPT-SciSciNet huggingface dataset:
Controlled collapse chip connection (C4)-an enabling technology

Much of the technical information presented herein has been published by either IBM or Motorola This paper provides a higher-level view of the benefits, considerations and leverage applications of the C4 and DCA technologies. A key to acceptance and use of a new or different technology is its application in successful products. Although C4 is not new and has-been utilized extensively by IBM, it is different to Motorola. DCA is a relatively new technology and, thus, has a shorter history. As a foundation, this paper discusses the key C4 and DCA technical features and describes some initial product applications at Motorola. This linkage shows the enabling characteristics of the C4 flip-chip technology. Finally, future trends and directions of C4 and DCA technologies are discussed. >
A Hierarchical Data Structure To Support Diagnostic Testing

The diagnostic testing of large integrated circuits is described using an electron-beam prober to measure internal waveforms. The design data of a specimen is displayed to guide interactive testing. Further, this design data is organized as a hierarchy of symbolic objects, to facilitate the extraction of circuit models. In particular, connected structures are maintained as entities, making it easier to generate simulated waveforms rapidly for comparison with measurements from designated nodes in the device. An implementation of the data structure is presented, in Ada, which was developed under contract for the US Army, Fort Monmouth, NJ.
Free radical complexes of copper(I): geometry and ground state

Abstract DFT calculations were performed on the singlet and triplet states of a series of copper(I)–bis(radical) complexes. For a copper(I)–bis(iminonitroxide) complex, the results are consistent with experimental data, predicting a triplet ground state and an excited singlet at 38.7 cm−1. For two related copper(I)–bis(verdazyl) complexes, the calculations predict a triplet ground state and singlet excited states at 58.6 and 34.9 cm−1, respectively; however both the minimized structure and singlet–triplet separation are inconsistent with experimental data. We suggest that the difference between theory and experiment is a result of intermolecular interactions within the crystal lattice.
Efficient Parallelization of H.264 Decoding with Macro Block Level Scheduling

The H.264 decoder has a sequential, control intensive front end that makes it difficult to leverage the potential performance of emerging manycore processors. Preparsing is a functional parallelization technique to resolve this front end bottleneck. However, the resulting parallel macro block (MB) rendering tasks have highly input-dependent execution times and precedence constraints, which make them difficult to schedule efficiently on manycore processors. To address these issues, we propose a two step approach: (i) a custom preparsing technique to resolve control dependencies in the input stream and expose MB level data parallelism, (ii) an MB level scheduling technique to allocate and load balance MB rendering tasks. The run time MB level scheduling increases the efficiency of parallel execution in the rest of the H.264 decoder, providing 60% speedup over greedy dynamic scheduling and 9-15% speedup over static compile time scheduling for more than four processors. The preparsing technique coupled with run time MB level scheduling enables a potential 7times speedup for H.264 decoding.
Design and Functional Evaluation of a Quasi-Passive Compliant Stance Control Knee–Ankle–Foot Orthosis

In this paper, we present the mechanical design, control algorithm, and functional evaluation of a quasi-passive compliant stance control knee-ankle-foot orthosis. The orthosis implements a spring in parallel with the knee joint during the stance phase of the gait and allows free rotation during the swing phase. The design is inspired by the moment-angle analysis of the knee joint revealing that the knee function approximates that of a linear torsional spring in the stance phase of the gait. Our orthosis aims to restore the natural function of a knee that is impaired by injury, stroke, post-polio, multiple sclerosis, spinal cord injury, patellofemoral pain syndrome, osteoarthritis, and others. Compared with state-of-the-art stance control orthoses, which rigidly lock the knee during the stance phase, the described orthosis intends to provide the natural shock absorption function of the knee in order to reduce compensatory movements both in the affected and unaffected limbs. Preliminary testing on three unimpaired subjects showed that compliant support of the knee provided by the orthosis explained here results in higher gait speed as well as more natural kinematic profiles for the lower extremities when compared with rigid support of the knee provided by an advanced commercial stance control orthosis.
Statistical ultrasonics: the influence of Robert F. Wagner

An important ongoing question for higher education is how to successfully mentor the next generation of scientists and engineers. It has been my privilege to have been mentored by one of the best, Dr Robert F. Wagner and his colleagues at the CDRH/FDA during the mid 1980s. Bob introduced many of us in medical ultrasonics to statistical imaging techniques. These ideas continue to broadly influence studies on adaptive aperture management (beamforming, speckle suppression, compounding), tissue characterization (texture features, Rayleigh/Rician statistics, scatterer size and number density estimators), and fundamental questions about how limitations of the human eye-brain system for extracting information from textured images can motivate image processing. He adapted the classical techniques of signal detection theory to coherent imaging systems that, for the first time in ultrasonics, related common engineering metrics for image quality to task-based clinical performance. This talk summarizes my wonderfully-exciting three years with Bob as I watched him explore topics in statistical image analysis that formed a rational basis for many of the signal processing techniques used in commercial systems today. It is a story of an exciting time in medical ultrasonics, and of how a sparkling personality guided and motivated the development of junior scientists who flocked around him in admiration and amazement.
Comparative Analysis Of Multiplexing Techniques For Interferometric Fiber Sensors

A number of techniques for the multiplexing of interferometric fiber sensors have been reported in recent years, and systems with up to eight sensor elements have been experimentally demonstrated. This paper presents a comparison of these various multiplexing approaches in terms of power budget, noise, bandwidth/sampling-rate requirements and crosstalk.
Effect of temperature on rate of development and viability of the cestode Hymenolepis nana in its intermediate host

Abstract The correlation was studied between temperature and rate of development of the cysticercoid of Hymenolepis nana in the intermediate host, Tribolium confusum. Beetles were infected at room temperature under standard conditions and transferred to each of 17 different temperatures investigated between the extremes of 10 and 43 °C. At 42 and 41 °C development was completed in 7 days but the rate was reduced and infectivity of the cysticercoids in the final host could not be obtained. Between 40 and 37 °C, the maximum rate of maturation of infective cysticercoids was obtained—4 days. The 30–32 ° range appeared physiologically optimal but increased the time of development to 5–5.5 days. A large increase in development time was required at lower temperatures, varying from 11 days at 25 ° to more than 50 days at 15 °C. H. nana appears well adapted to the higher temperatures studied (up to 40 °C) and poorly adapted at the lower range (15 °C), in contrast to the reverse condition for the rat tapeworm, Hymenolepis diminuta.
19-Nordeoxycorticosterone, aldosterone, and corticosterone excretion in sequential urine samples from male and female rats.

Abstract 19-Nordeoxycorticosterone (19-norDOC) is a powerful mineralocorticoid that has been postulated to play a role in the pathogenesis of some forms of hypertension in the rat. We measured the daily excretion of 19-norDOC, aldosterone, and corticosterone in intact male and female SR/jr rats for 20 consecutive days. The excretion of corticosterone and aldosterone was higher during the first 4 days of collection and remained relatively stable for the rest of the collection period. The excretion of corticosterone and aldosterone was not different between male and female rats. The excretion of 19-norDOC, which, as has been reported previously, was significantly higher in female than male rats, varied over 600% from day to day in some individual rats. The variability in the excretion of 19-norDOC did not correlate with the excretion of aldosterone or corticosterone and did not appear to coincide with an estrous cycle. These studies also indicate that when the urinary excretion of steroids is intended to be used as an indication of steroid production in the basal state, a period of at least 4 days of acclimatization in metabolic cages, even for animals accustomed to handling, is necessary to obtain stable excretions. (Steroids 56 :451–454, 1991)
A distance of 133–137 parsecs to the Pleiades star cluster

Nearby 'open' clusters of stars (those that are not gravitationally bound) have played a crucial role in the development of stellar astronomy because, as a consequence of the stars having a common age, they provide excellent natural laboratories to test theoretical stellar models. Clusters also play a fundamental part in determining distance scales. The satellite Hipparcos surprisingly found that an extensively studied open cluster—the Pleiades (also known as the Seven Sisters)—had a distance of D = 118 plusminus 4 pc (refs 2, 3), about ten per cent smaller than the accepted value. The discrepancy generated a spirited debate because the implication was that either current stellar models were incorrect by a surprising amount or Hipparcos was giving incorrect distances. Here we report the orbital parameters of the bright double star Atlas in the Pleiades, using long-baseline optical/infrared interferometry. From the data we derive a firm lower bound of D > 127 pc, with the most likely range being 133 < D < 137 pc. Our result reaffirms the fidelity of current stellar models.
Equivalence and its use

Abstract When we plot A against B in a graph we have an equivalence: If more A then more B saying that if not more B then not more (less) A. A relationship is an equivalence. But when there are three things, A, B and C, there are quite a number of equivalences. In this article 16 expressions are presented; when these are taken in pairs, each pair is an equivalence. For example, it was found that abundance of the alga listhodiscus luteus in flasks with tintinnids prevented the tintinnids growth, while the tintinnids grew well with lesser amounts of the alga. The same occurred in Narragansett Bay, U.S.A.; with abundance of the alga there was low amount of tintinnids while tintinnids thrived with less alga. An equivalence description is this: ‘If O. luteus is abundant experimentally or is abundant observationally in nature, then it is lethal to tintinnids’ is equivalent to ‘If O. luteus is not lethal to tintinnids, then it is neither experimentally nor observationally abundant’. This illustrates: ‘If A or B then C’ equivalent to ‘If not C then not A and not B’. A wholly different path of endeavor is to choose an equivalence and then to fit all the data to it. This is done in the last of five cases presented.
Temperature Dependence of Cation Distribution and Oxidation State in Magnetic Mn-Fe Ferrite Nanocrystals

The magnetic properties of spinel nanoparticles are determined by crystal chemistry issues such as cation distribution and oxidation states. The cation distribution and oxidation state of Mn -Fe spinel nanoparticles have been systematically studied at various temperatures by using neutron diffraction and electron energy loss spectroscopy, respectively. The Mn-Fe spinel nanoparticles prepared by coprecipitation have a high degree of inversion with 61% of the tetrahedral sites occupied by Fe 3+ cations. The degree of inversion correlates with the distribution expected from random occupancy of cations consisting of Fe (60%) and Mn (40%). After heat treatment in a vacuum, the cation distribution reaches an equilibrium state with a 29% inversion. Initially, one-half of the Mn cations are in the +3 oxidation state and the other half are in the +2 oxidation state. Mn 3+ cations are slowly and irreversibly reduced to Mn 2+ with increasing temperature. When the temperature approaches 600 °C, all Mn cations are in the +2 state. These results provide direct evidence for the temperature-dependent change of crystal chemistry in Mn-Fe spinel nanoparticles, which has been closely related with the controversy on attributing the changes in the magnetic properties of the nanoparticles to crystallite size effect. These results will also provide an understanding of how to control crystal chemistry in order to control the properties of these magnetic nanoparticles.
Peaks of optical and X-ray afterglow light curves

The peaks of 30 optical afterglows and 14 X-ray light-curves display a good anticorrelation of the peak flux with the peak epoch: F_p ~ t_p^{-2.0} in the optical, F_p ~ t_p^{-1.6} in the X-ray, the distributions of the peak epochs being consistent with each other. We investigate the ability of two forward-shock models for afterglow light-curve peaks -- an observer location outside the initial jet aperture and the onset of the forward-shock deceleration -- to account for those peak correlations. For both models, the slope of the F_p - t_p relation depends only on the slope of the afterglow spectrum. We find that only a conical jet seen off-aperture and interacting with a wind-like medium can account for both the X-ray peak relation, given the average X-ray spectral slope beta_x = 1.0, and for the larger slope of the optical peak relation. However, any conclusion about the origin of the peak flux - peak epoch correlation is, at best, tentative, because the current sample of X-ray peaks is too small to allow a reliable measurement of the F_p - t_p relation slope and because more than one mechanism and/or one afterglow parameter may be driving that correlation.
Mercury and metals in South African precipitation

Abstract Even though mercury (Hg) is a global pollutant there are few studies of its concentration in the Southern Hemisphere, either in the atmosphere or in atmospheric deposition, and this is particularly true for Africa and developing nations such as South Africa. Emission inventories suggest that there is the potential for anthropogenic impact through elevated deposition in South Africa to sensitive ecosystems. To begin examining such impact, measurements of Hg and other trace metals (Al, Fe, Mn, Co, Ni, Cu, Zn, Cd and Pb) were made of rain collected using a bulk deposition collector at Cape Point, at the tip of Africa, and in Pretoria, a city within the industrial and mining heartland of South Africa. As expected, concentrations and fluxes were elevated in Pretoria, the more urban location. However, there is also evidence that Cape Point site can be impacted by regional pollution during the winter. The volume weighted mean Hg concentration at Cape Point was 10.6 ng L−1 compared to 15.8 ng L−1 in Pretoria. Comparison of rain concentrations for Hg and other metals, and relative fluxes (normalized to Al), indicate the importance of regional sources of contamination to both sites. The importance of impacted air masses at Cape Point was further investigated using ancillary data (CO and Rn) and back trajectory analysis. Overall, these results suggest that Hg and trace metal concentrations and fluxes are comparable to other locations in the world that are impacted by regional anthropogenic sources.
The role of temporomandibular disorders and cervical dysfunction in tension-type headache.

It has been estimated that 30% to 80% of the population has at least one tension-type headache each year. Tensiontype headaches can be located in any region of the head, which can confuse a differential diagnosis with temporomandibular joint disorders and cervical dysfunction. The roles of temporomandibular joint disorders and cervical dysfunction in tension-type headache are evaluated. Definitions, pathophysiology, and treatment considerations for each are discussed.
Variation in esophagectomy outcomes in hospitals meeting Leapfrog volume outcome standards.

Background The Leapfrog Group established a minimum hospital case volume of 13 for esophageal resection in a response to known improved outcomes in larger volume centers. The aim of this study was to evaluate variation in short-term outcomes among hospitals that met the Leapfrog volume criteria. Methods Using the Washington State Comprehensive Hospital Abstract Reporting System, a retrospective cohort design evaluated all patients (≥18 years) undergoing esophageal resection for any diagnosis since the introduction of Leapfrog standards (2000 to 2007). The main outcome measures were hospital stay, readmissions within 30 days of discharge, discharge to an institutional care facility, operative reinterventions, and 90-day mortality. Results A total of 1,505 adult Washington state residents underwent esophageal resection without complex reconstruction (1,352 elective [89.8%]). Of 45 hospitals reporting at least one procedure, 5 (11%) met Leapfrog volume standards. Leapfrog hospitals accounted for 62% of the total elective volume. Overall, elective patients at Leapfrog hospitals had a lower adjusted risk of death compared with those at hospitals that did not meet criteria (odds ratio 0.50, p = 0.02). Across the different Leapfrog hospitals there was over fivefold variation in 90-day mortality (1.7% to 10.2%), 2.5-fold variation in reinterventions (8% to 20%), and fourfold variation in discharges to an institutional care facility (5.3% to 19.8%). Length of stay and readmission rate varied less. Conclusions Although referral to high-volume centers has been an important advance for complex surgical procedures, there is still a substantial degree of variability in outcomes among hospitals that met Leapfrog volume criteria for esophagectomy. Metrics such as process, individual surgeon volume, and risk-adjusted outcome measures may yield further opportunities for quality improvement that extend beyond hospital volume-based assessments.
Host markers and correlated mutations in the overlapping genes of influenza viruses: M1, M2; NS1, NS2; and PB1, PB1-F2

The influenza A viruses have three gene segments, M, NS, and PB1, which code for more than one protein. The overlapping genes from the same segment entail their interdependence, which could be reflected in the evolutionary constraints, host distinction, and co-mutations of influenza. Most previous studies of overlapping genes focused on their unique evolutionary constraints, and very little was achieved to assess the potential impact of the overlap on other biological aspects of influenza. In this study, our aim was to explore the mutual dependence in host differentiation and co-mutations in M, NS, and PB1 of avian, human, 2009 H1N1, and swine viruses, with Random Forests, information entropy, and mutual information. The host markers and highly co-mutated individual sites and site pairs (P values < 0.035) in the three gene segments were identified with their relative significance between the overlapping genes calculated. Further, Random Forests predicted that among the three stop codons in the current PB1-F2 gene of 2009 H1N1, the significance of a mutation at these sites for host differentiation was, in order from most to least, that at 12, 58, and 88, i.e., the closer to the start of the gene the more important the mutation was. Finally, our sequence analysis surprisingly revealed that the full-length PB1-F2, if the three stop codons were all mutated, would function more as a swine protein than a human protein, although the PB1 of 2009 H1N1 was derived from human H3N2.
A Review of the Bilobed Flap's Design with Particular Emphasis on the Minimization of Alar Displacement

Background. The bilobed flap excels in the surgical reconstruction of the distal nose. Unfortunately the aesthetic success of the flap is occasionally limited by the production of distracting alar displacement. Objective. To review elements of the bilobed flap's design with a particular emphasis on understanding techniques to minimize distortion of the alar margins. Conclusion. With a proper understanding of the bilobed flap's intricate design, the surgeon can anticipate those factors that are most likely to produce temporary or permanent alar asymmetry. Appropriate prospective flap design and meticulous surgical technique can significantly minimize the risk of a poor surgical outcome.
Effect of in vitro exposure to hydrogen sulfide on rabbit alveolar macrophages cultured on gas-permeable membranes☆

Abstract Rabbit alveolar macrophages (AM) were cultured on gas-permeable membranes (Petriperm dishes) and standard 25-cm2 plastic tissue-culture flasks (Falcon Plastics) and exposed to H2S (50–60 ppm). Exposure of AM to approximately 54 ppm of H2S for 24 hr during culture on gas-permeable membranes reduced the percentage of AM that phagocytized 2.02-μm polyvinyl toluene beads to 5% of control values. In contrast, AM cultured on plastic tissue-culture flasks showed no decrease in phagocytic ability when exposed to similar concentrations of H2S. Unexposed AM were equally phagocytic under both culture systems. A decrease in phagocytic capability was most pronounced under continuous exposure regimens. Above a critical combination of H2S concentration and duration of exposure, cessation of exposure did not halt a time-dependent degradation of phagocytic ability. Scanning electron microscopy of cultured AM exposed for 24 hr to 54 ppm H2S revealed a general decrease in cell-surface ruffling and a pronounced loss of pseudopodia. Transmission electron microscopy of AM cultures exposed to 54 ppm H2S for 24 hr revealed extensive disruption of interior organelles, cytoplasmic membrane degradation, and sharply reduced cell-surface ruffling.
Characterization of κ-opioid receptor transcripts expressed by T cells and macrophages

We have found that the immature T cell lines R1.1 and DPK and the macrophage lines P388D1 and WEHI-3 also express κ-opioid receptor (KOR) mRNA. Characterization of the KOR transcripts in both brain tissue and these T cells has revealed both the normal full-length as well as a truncated form of the mRNA. Our results show that the truncated transcript lacks the second exon. Primary macrophages express this truncated form of the transcript in the absence of detectable levels of the full-length form. These results suggest a degree of heterogeneity in the expression of the opioid receptors which has not previously been reported.
Towards a General Framework for Optimal Role Mining: A Constraint Satisfaction Approach

Role Based Access Control (RBAC) is the most widely used advanced access control model deployed in a variety of organizations. To deploy an RBAC system, one needs to first identify a complete set of roles, including permission role assignments and role user assignments. This process, known as role engineering, has been identified as one of the costliest tasks in migrating to RBAC. Since many organizations already have some form of user permission assignments defined, it makes sense to identify roles from this existing information. This process, known as role mining, has gained significant interest in recent years and numerous role mining techniques have been developed that take into account the characteristics of the core RBAC model, as well as its various extended features and each is based on a specific optimization metric. In this paper, we propose a generic approach which transforms the role mining problem into a constraint satisfaction problem. The transformation allows us to discover the optimal RBAC state based on customized optimization metrics. We also extend the RBAC model to include more context-aware and application specific constraints. These extensions broaden the applicability of the model beyond the classic role mining to include features such as permission usage, hierarchical role mining, hybrid role engineering approaches, and temporal RBAC models. We also perform experiments to show applicability and effectiveness of the proposed approach.
Mesenteric vascular responses to i.v. administration of lipoxin A4 and lipoxin B4 in the conscious rat.

Lipoxin A4 and lipoxin B4 are newly discovered lipoxygenase-interacting products of leukocytes which might have a role in cardiovascular events associated with anaphylaxis. We have tested this possibility by systemic administration of both LXA4 and LXB4 to the conscious rat while monitoring systemic and regional hemodynamic changes. LXA4 and LXB4 (1–100 μg/kg) produced dose-dependent constriction of the mesenteric vessels, up to + 123 ± 23% and + 50 ± 9% for LXA4/B4, respectively. Dose-related changes were not observed in arterial blood pressure, heart rate, renal (LXB4) and hindquarter blood flow. We suggest that LXA4 and LXB4 might affect selective vascular beds, such as the mesenteric vessels, and contribute to variations in blood flow in specific pathophysiological states.
A Diode Multiplexer for Analog Voltages

A diode muliplexer switch is described for time-sharing 64 analog voltages in a digital computer application. Apart from its relative simplicity and economy, the multiplexer characteristics of microsecond switching speeds, maximum settling time of 133 microseconds for a 10-volt operating range, and accuracies of better than 1 per cent full scale are confirmed both by theoretical equations and by experimental results.
Self-reported physical activity among middle-aged cancer survivors in the United States: Behavioral Risk Factor Surveillance System Survey, 2009.

INTRODUCTION Regular physical activity (PA) can improve health outcomes in cancer survivors, but the rate of adherence to PA recommendations among middle-aged survivors is unclear. We examined adherence to PA recommendations among cancer survivors and controls. We sought to identify correlates of adherence to PA and to determine whether PA adherence is associated with health-related quality of life (HRQOL) among cancer survivors. METHODS We examined PA adherence among 8,655 cancer survivors and 144,213 control subjects aged 45-64 years who were respondents to the 2009 Behavior Risk Factor Surveillance System survey. We used multinomial logistic regression to assess associations between PA adherence and demographic, psychosocial, and clinical factors, and multivariable linear regression to assess the relationship between PA adherence and HRQOL of cancer survivors. RESULTS Cancer survivors and control subjects had similar rates of PA adherence. Of the survivors, 47% met the recommendations of 150 minutes of moderate-intensity PA or 120 minutes of vigorous-intensity PA per week, 41% were somewhat active, and 12% were sedentary. Compared with cancer survivors who were sedentary, survivors who were somewhat active were less likely to be obese (odds ratio [OR], 0.65; P < .007), and those who met PA recommendations were less likely to be overweight (OR, 0.61; P < .002) or obese (OR, 0.33, P < .001). Regression analysis indicated that PA adherence was positively correlated with HRQOL (P < .001). CONCLUSION Most cancer survivors did not meet PA recommendations, but those who are active seem to have improved HRQOL. Therefore, targeted interventions to improve adherence to PA among cancer survivors are needed.
Striving for empathy: affinities, alliances and peer sexuality educators

Peer sexuality educators' accounts of their work reveal two approaches to empathy with their students: affinity and alliance. ‘Affinity-based empathy’ rests on the idea that the more commonalities sexuality educators and students share (or perceive they share), the more they will be able to empathise with one another, while ‘alliance-based empathy’ is an analytical process of considering the social contexts that shape others' lives. We assess the potential for each source of empathy to equip peer sexuality educators to counter hierarchical models of teaching and learning, effect social change and promote the interests of youth. Because shared identity categories prove difficult to manage and sustain, we find affinity alone does not offer peer sexuality educators lasting opportunities to work with young people. In contrast, developing alliance-based empathy prepares peer educators – indeed, all sexuality educators – to identify inequalities or barriers that others face and seek ways to foster social change...
Estimating carrying capacity for sandhill cranes using habitat suitability and spatial optimization models

Northern Ohio supports a small population of greater sandhill cranes (Grus canadensis tabida) that is currently listed as state-endangered. Population restoration efforts are currently under consideration, although it is not known if habitats in the state can support additional nesting pairs. Accurate estimates of breeding pair carrying capacity are necessary before conservation efforts can be effectively developed and implemented. We estimated carrying capacity for nesting sandhill cranes using habitat suitability and spatial optimization models. We first developed a spatially explicit habitat suitability index (HSI) model to identify suitable nesting sites at five locations in northern Ohio. We then used the HSI output to estimate the carrying capacity at each location. We modeled carrying capacity as an anti-covering location problem, a spatial optimization model that determines the maximum number of breeding pairs an area can support, given that nests must be spaced 3000 m apart. Our results indicate that habitats in Ohio where cranes currently breed are near carrying capacity, while unoccupied suitable habitats are available in other portions of the state. This analysis enables wildlife managers to identify priority locations for crane conservation in Ohio and to determine which restoration efforts (e.g. habitat restoration or population augmentation) are most likely to succeed at each location. Our methodology provides an important and innovative conservation tool that can be applied to other species with strong attachment to sites (e.g. nest or den) that are optimally spaced at some minimum distance from conspecifics, competitors, predators, or sources of disturbance.
Faecal steroid loss in healthy subjects during short-term treatment with ursodeoxycholic acid

Faecal steroid loss in healthy subjects during short-term treatment with ursodeoxycholic acid has been investigated. The data shows conclusively that lithocholic acid, a known co-mutagen and co-carcinogen is the major bacterial metabolite of ursodeoxycholic acid in the human intestine. Although ursodeoxycholic acid is now the drug of choice for dissolution of cholesterol gallstones, elevation of intestinal lithocholic acid may have long-term repercussions since it has been demonstrated that a high faecal lithocholic acid: deoxycholic acid ratio shows a positive correlation with the incidence of colorectal cancer.
The unusual supernova SN1993J in the galaxy M81

Supernova 1993J in the galaxy M81 is the second-brightest type II supernova observed this century, surpassed only by SN1987A in the Large Magellanic Cloud. Here we report the evolution of the photometric and spectral properties of SN1993J for the first 50 d following its discovery. The behavior of this supernova is unusual, showing features typical of type II supernovae near the initial maximum, but with the strong helium lines characteristic of type Ib supernovae at later times. This implies that the progenitor star had an unusually thin hydrogen envelope (compared to normal type II progenitors), suggesting that significant mass loss had taken place before the explosion. Application of an expanding photosphere model to our data provides an estimate of the distance to the supernova of 2.6 +/- 0.4 Mpc, broadly consistent with the distance to M81 determined using Cepheid variable stars. Supernova models that more closely match the atypical spectral features of SN1993J may change the inferred distance, and should provide better constraints on the structure of the progenitor.
The COMT Val158Met polymorphism and temporal lobe morphometry in healthy adults

We examined the relationship between COMT Val158Met genotype and temporal lobe volumes, including the caudate as a control region. Thirty-one healthy subjects completed 1.5T brain MRI and genotyping. After controlling for demographics, Val158 allele homozygotes exhibited significantly smaller temporal lobe and hippocampal volumes, with a trend for smaller amygdala volumes.
Debunking dogma and developing theses.

It is a challenge to write any brief commentary on the research, observations, speculations and theories promulgated by each of these authors individually, but when they are together the task may be just be hopeless! However, I will try to address just a few of the many ideas, observations and speculations presented in this issue [1] because this is an essay rich in important inferences and serves well to make us reconsider accepted paradigms. Nowhere is this more important in oncology than when considering breast cancer for it has been the study of this disease that has produced dogma regarding the aetiology, natural history and treatment of all types of cancer [2]. The term ‘‘dogma’’ is used with full appreciation of all its religious and authoritative connotations. Critical reflection on such strongly held beliefs is always a good thing, but it is especially true in medical science. We are indebted to the authors for their presenting information in a way that invites interpretation at variance to generally accepted theses. Their selective review of the history of our understanding of cancer is informative and enjoyable. However, the discussion of the natural history of untreated breast cancer seems beside the point. Despite the paucity of relevant data documenting the dire consequences of leaving breast cancer untreated, clinical observation confirms both the local growth and the metastatic spread of the disease leading to morbid symptoms and death. There are surely exceptions as the anecdote presented, but unfortunately they are rare indeed and surely nothing on which to base the management of a patient. The authors reach into a rich lode when they discuss the possible deleterious influence of surgery. Not only have there been concerns about untoward effects of this
Temperature dependence of ion-molecule collision phenomena: An application of ion cyclotron resonance spectroscopy to the determination of reactive and momentum transfer rate constants

Abstract A temperature dependent ICR cell capable of operation in the range 80–450 K is described. The problem that thermal transpiration poses regarding the precise pressure in the cell at various temperatures is discussed in detail. Both common sense considerations and experimental tests strongly suggest that effusive flow governs the pressure in the ICR cell at all temperatures for the molecules considered here. Two types of data are presented corresponding to the measurement of the temperature dependence of both momentum transfer and reactive rate constants. Momentum transfer rate constants measured over the range 80–425 K include N2+−/N2, Ne+−/Ne, N2+−/Ne, CH5+/CH4 and CF3+/CF4. The system C4H9+/neo-C5H12 was studied from 216–380 K. The systems N2+−/N2 and Ne+−/Ne have rate constants that increase with temperature and absolute magnitudes larger than the Langevin prediction. Symmetric charge transfer is suggested as the reason for this dependence. The N2+−/Ne system rate constant is less than the Langevin prediction and does not increase with temperature in agreement with this interpretation. The CH5+/CH4, CF3+/CF4 and C4H9+/C5H15 systems all exhibit rate constants considerably larger than the Langevin prediction. Since these systems are all relatively unreactive, it is suggested the Langevin model is inappropriate and a treatment similar to that given recently by Beauchamp and Ridge is required. Reactive systems studied include charge transfer in He+−/N2 and proton transfer in CH4+−/CH4. Rate constants in each of these systems were measured from 80–425 K. The He+−/N2 system rate constant was independent of temperature in agreement with the flowing afterglow data of Lindinger et al. The CH4+−/CH4 rate constant decreased with decreasing temperature. A plot of lnk vs.T−1 yielded a “barrier” in this reaction of 80 cal mol−1.
Signaling pathways in ischemic preconditioning

Ischemic preconditioning renders the heart resistant to infarction from ischemia/reperfusion. Over the past two decades a great deal has been learned about preconditioning’s mechanism. Adenosine, bradykinin, and opioids act in parallel to trigger the preconditioned state and do so by activating PKC. While adenosine couples directly to PKC through the phospholipases, bradykinin and opioids do so through a complex pathway that includes in order: phosphatidylinositol 3-kinase (PI3-kinase), Akt, nitric oxide synthase, guanylyl cyclase, PKG, opening of mitochondrial KATP channels, and activation of PKC by redox signaling. There are even differences between the opioid and bradykinin coupling as the former activates PI3-kinase through transactivation of the epidermal growth factor receptor while the latter has an unknown coupling mechanism. Protection stems from inhibition of formation of mitochondrial permeability transition pores early in reperfusion through activation of the survival kinases, Akt and ERK. These kinases are activated as a result of PKC somehow promoting signaling from adenosine A2 receptors early in reperfusion. The survival kinases are thought to inhibit pore formation by phosphorylating GSK-3β. The reperfused heart requires the support of the protective signals for only about an hour after which the ischemic injury is repaired and the signals are no longer needed.
Macromolecular Response of Individual Algal Cells to Nutrient and Atrazine Mixtures within Biofilms

Pollutant effects on biofilm physiology are difficult to assess due to differential susceptibility of species and difficulty separating individual species for analysis. Also, measuring whole assemblage responses such as metabolism can mask species-specific responses, as some species may decrease and others increase metabolic activity. Physiological responses can add information to compositional data, and may be a more sensitive indicator of effect. It is difficult, however, to separate individual species for biochemical analyses. Agricultural runoff often contains multiple pollutants that may alter algal assemblages in receiving waters. It is unclear how mixtures containing potential algal growth stimulators and inhibitors (e.g., nutrients and herbicides) alter algal assemblage structure and function. In research presented here, algal biofilms were exposed to nutrients, atrazine, and their mixtures, and assemblage-level structural and functional changes were measured. Synchrotron infrared microspectroscopy (IMS) was used to isolate the biochemical changes within individual cells from a dominant species of a green alga (Mougeotia sp.), a diatom (Navicula sp.), and a cyanobacterium (Hapalosiphon sp.). At the assemblage level, mixtures generally increased algal biovolume, decreased chlorophyll a, and had no effect on metabolism or ammonium uptake. Navicula had a strong negative response to atrazine initially, but later was more affected by nutrients. Hapalosiphon responded positively to both atrazine and nutrients, and Mougeotia did not exhibit any biochemical trends. Generally, biochemical changes in each species were similar to cells experiencing low stress conditions, with increased relative protein and decreased relative lipid. IMS provided direct evidence that individual species in a natural biofilm can have unique responses to atrazine, nutrients, and mixtures. Results suggest that the initial benthic community composition should have a strong influence on the overall impact of agricultural pollutants.
Using a Centrality Index to Determine the Contribution of Restored and Volunteer Plants in the Restoration of Plant-Pollinator Mutualisms on a Reclaimed Strip Mine

The restoration of ecosystem function relies, at least partly, on restoring services provided by mutualists. If the goal of restoration is to assemble functional and stable communities, particular care should be taken to identify and attract those species that contribute most to long-term community stability. Land managers and ecologists can use centrality indices, a group of network statistics that measure the relative importance of individuals within a community, to objectively determine the contribution of particular plant species to overall restoration efforts. Our objective was to compare the role of flowers planted as part of the restoration effort to those plants volunteering at the restoration site, either native adventives or non-native invaders, in support of the pollinator community. Further, we sought to determine how this relationship varied with changes in relative floral abundance. We found that plants cultivated as part of the restoration effort were preferred by pollinators, attracted the greatest abundance and richness of pollinators, and were the most central in our plant-pollinator networks compared to volunteers, despite the greater abundance of volunteer plants across the site. We also found that the role of all plants was density dependent; plants of every group attracted more pollinators in plots where they had greater relative abundance. We conclude that centrality indices provide a tool for planning and monitoring the restoration of important functional relationships and allow land managers and ecologists to objectively determine the contribution of particular plants to overall community structure and function.
Role of the C-Terminal 28 Residues of β2-Microglobulin in Amyloid Fibril Formation†

Beta2microglobulin (beta2m) is the major protein component of the fibrillar amyloid deposits isolated from patients diagnosed with dialysis-related amyloidosis (DRA). While investigating the molecular mechanism of amyloid fibril formation by beta2m, we found that the beta2m C-terminal peptide of 28 residues (cbeta2m) itself forms amyloid fibrils. When viewed by electron microscopy, cbeta2m aggregates appear as elongated unbranched fibers, the morphology typical for amyloids. Cbeta2m fibers stain with Congo red and show apple-green birefringence in polarized light, characteristic of amyloids. The observation that the beta2m C-terminal fragment readily forms amyloid fibrils implies that beta2m amyloid fibril formation proceeds via interactions of amyloid forming segments, which become exposed when the beta2m subunit is partially unfolded.
Identifying the rules of engagement enabling in silico leukocyte rolling, activation, and adhesion

Objectives: Leukocyte rolling, activation, and adhesion on endothelial cell surfaces are key events during leukocyte recruitment to tissues during the inflammatory process. The interactions between leukocytes and endothelial cell surfaces during rolling, activation, and adhesion are complex and involve ligand-binding events between several combinations of receptorligand pairs. Spatially restricted signaling events between chemokine receptors and local integrins as well as lateral diffusion and clustering of integrins are thought to play important roles in mediating the transition from rolling to adhesion. The objective of this project was to develop a novel computational model that aimed at gaining a fundamental understanding of the spatiotemporal events and key rules of engagement that determine when and how leukocytes are able to adhere to endothelial cell surfaces during inflammatory conditions. Methods: We used the synthetic modeling approach to construct a multilevel, multiagent, in silico model of leukocyte rolling, activation, and adhesion. Object-oriented software components were designed, verified, plugged together, and then operated in ways that represent the mechanisms and processes believed responsible for leukocyte rolling and adhesion. The in silico system constructed was a discrete event, discrete space, and discrete time analogue of the entire parallel plate flow chamber system commonly used to study leukocyte rolling and adhesion in vitro. This modeling approach allowed us to represent the spatial and discrete event phenomena that are thought to occur in vitro and in vivo. Results: We previously reported details of the model and initial results of in silico rolling and adhesion on P-selectin and VCAM-1 substrate in the presence of GRO-alpha chemokine (PMID 17408504): in silico leukocyte movement is a function of (1) number and type of bonds, and (2) location of the bond-containing patches at the interface. Our current effort has extended the model and increased resolution to enable exploration of the role of lateral diffusion and clustering of LFA-1 integrin in mediating rolling and adhesion to ICAM-1 substrate. Conclusions: These new methods represent important progress in gaining a fundamental understanding of the spatiotemporal events and key rules of engagement that determine when and how leukocytes adhere to endothelial cell surfaces during inflammation. The current model and results represent an important step in developing scientifically useful validated simulations of leukocyte recruitment under physiologic and pathophysiologic conditions.
Extensions of paranasal sinus tumors and inflammatory disease as evaluated by CT and pluridirectional tomography.

CT and pluridirectional tomography are compared in their ability to show the extent of paranasal sinus tumors or benign aggressive processes. Thirty-one cases are reviewed; CT was superior to pluridirectional tomography in showing spreads of tumor to all clinically important areas, including the infratemporal fossa, nasopharynx, orbit, and intracranial compartment. CT not only consistently allowed less equivocal interpretation, but also enabled us to qualify orbital involvement as intra- or extraconal, and to quantitate better both brain and infratemporal fossa involvement. We feel that CT scanning is the better way to determine the extent of such pathology.
The Interstellar Medium in the Central 1 Kiloparsec of M82

The spatial distribution of the 158 micron forbidden C II emission in the central 1 kiloparsec of the infrared galaxy M82 is discussed, and the detection of two fine-structure lines of forbidden O I and forbidden O III at 146 and 52 microns is reported. Within 500 pc of the nucleus, the far-infrared emission lines contain about 200 million solar luminosities. The neutral gas in the inner disk is in dense, relatively small clouds, thin filaments, or sheets of very low volume filling factor, associated with a lower density ionized medium of moderately high filling factor. Within 500 pc of the nucleus, about 30 million solar masses is contained in H II regions and 30 million solar masses in photodissociation regions. There is a component of ionized and neutral gas near LSR of roughly 150 km/s centered near the compact radio source 41.9 + 58 and elongated along the minor axis of M82. The gas is especially dense in this region and appears to be associated with X-ray emission and the inner H-alpha filaments.
A Suggestion to Climate Scientists and the Intergovernmental Panel on Climate Change

Scientists and the general public alike encounter scientific terms such as climate change, global warming, greenhouse effect, and carbon dioxide a few times every day in newspapers, radio broadcasts, and television news, as well as in conversation. This is perhaps the first time in the history of science that a scientific issue has gotten so much attention from the public. As a scientist, I am pleased about the public's interest in science. Unfortunately, I have found that this great interest in climatology is largely the result of a proliferation of confusing stories in the media that are based on misinterpreted information about the greenhouse effect of carbon dioxide. Many people bring up several misunderstood issues when I discuss the present warming trend. Even some policy makers and government officials seem to be confused.