cssi/SciSciGPT-SciSciNet huggingface dataset:
Definition of Critical Asthma Syndromes

Urgent visits to the clinic and emergency department for acute severe asthma exacerbations are all too frequent. Existing national guidelines do not present consistent or specific recommendations for the evaluation and treatment of individual asthma patients in respiratory distress. In this vein, we propose the term "critical asthma syndrome" (CAS) to describe any child or adult who is at high risk for fatal asthma. Acute severe asthma, refractory asthma, status asthmaticus, and near-fatal asthma all describe CAS where physical exhaustion from the overwhelming work of breathing leads to respiratory arrest and death from hypoxia or related complications. The authors of this supplement seek to emphasize the importance of early recognition, prompt and coordinated evaluation, and treatment of CAS in the emergency department, hospital, and intensive care units by experienced healthcare provider teams. CAS is not severe persistent asthma where control of symptoms and prevention of exacerbations are targets of chronic disease management in the outpatient setting. The authors address the distinctions between the two entities throughout the supplement, and elaborate on the considerations important in the care of a critically ill patient, including the common errors to avoid. In addition, gaps in knowledge and clinical experience in regards to critical asthma are highlighted. Knowledge gaps include a lack of understanding of how to recognize CAS, how to coordinate and integrate hospital and outpatient resources, when to further phenotype patients with critical asthma in order to facilitate effective treatment, and how to prevent future acute exacerbations. Lastly, CAS is complicated by the fact that asthma care in diverse healthcare settings is haphazard. We recommend that primary care physicians refer patients promptly to an asthma specialist for consultation to reduce the frequency of acute exacerbations and prevent the development of CAS.
Relative brightness of specular and diffuse reflection

Inhomogeneous dielectric surfaces exhibit both diffuse and specular reflection components. Although various reflection models have been proposed for both of these components, the prediction of the relative strengths of these components in computer vision and computer graphics has so far not had a strong physical motivation. We propose a reflectance model for combined diffuse and specular reflection from dielectric materials that involves purely physical parameters (i.e., no ad hoc weighting of specular and diffuse components). This reflectance model is used to predict the relative strength of diffuse and specular reflection components ih terms of imaging geometry, dielectric surface parameters, and solid angular extent of incident light. We derive lower bounds on the contrast ratio between a specularity and surrounding diffuse reflecting regions. These can be used effectively to rule out highly contrasting diffuse reflecting regions being misidentified as pecularities under a number of conditions that can significantly aid intensity-based specularity detection methods, and in turn image understanding. The presented theoretical developments can be used to predict the photometric dynamic range of illuminated objects, which can be essential to inspection methods in machine vision. These developments can also be used in computer graphics for the physically precise rendering of the relative strengths of specular and diffuse reflection from inhomogeneous dielectrics.
Cellular Adaptive Inflammation Mediates Airway Granulation in a Murine Model of Subglottic Stenosis

Objective. To determine the contribution of B- and T-cell–mediated inflammation in a murine airway granulation model.Study Design. Pilot study in a modified murine model.Setting. Philadelphia VA Medical Center Research Building.Subjects and Methods. Laryngotracheal complexes (LTCs) from 54 donor C57BL/6 mice were harvested and divided into 3 groups: (1) uninjured, (2) mechanically injured using a wire brush, and (3) chemically injured using hydrochloric acid. One donor LTC from each group was placed in deep dorsal subcutaneous pockets of either severe combined immunodeficiency (SCID)– or C57BL-recipient mice, for a total of 3 transplanted tracheas per recipient mouse. After 3 weeks, the transplanted LTCs were harvested from both C57BL- and SCID-recipient mice. Tissues were fixed, sectioned, and stained with hematoxylin and eosin. Representative slides were reviewed by a blinded pathologist to determine the formation of granulation tissue and graded as to the degree of formation of granulation tissue.Resul...
VESSEL ACCIDENT OIL-SPILLAGE: POST US OPA-90

Abstract The vessel accident oil-spillage literature has focused on oil-cargo vessels, tankers and tank barges, implicitly assuming that these vessels incur greater accident oil-spillage than other (i.e., non-oil-cargo) vessels which just carry oil in their fuel tanks. This study investigates the validity of this assumption for the post US OPA-90 (Oil Pollution Act of 1990) period by investigating determinants of vessel accident oil-spillage, where one of the hypothesized determinants is type of vessel (including both oil-cargo and non-oil-cargo vessels). Tobit regression estimates of vessel accident oil-spillage functions suggest that tank barges have incurred greater in-water and out-of-water oil-spillage for the post OPA-90 period than non-oil-cargo vessels; alternatively, tankers have not incurred greater out-of-water (in-water) oil-spillage than non-oil-cargo vessels (except for freight ships). The policy implication is that greater attention needs to be given to reducing tank barge accident oil-spillage in the post OPA-90 period.
Evaluation of Emission Model for Diffusion Flame, Rich/Lean, and Premixed Lean Combustors

A recently developed emission model was used to predict the emission characteristics of a gas turbine combustor. The model involves a multiple-step reaction scheme that addresses the breakup of the fuel into an intermediate hydrocarbon compound of variable structure. The reaction rate expressions developed in the present approach simulated the results obtained using a detailed chemical kinetic mechanism over a wide range of operation that is typically encountered in a conventional diffusion flame combustor, as well as low NOx rich/quench/lean, and premixed/prevaporized lean combustion concepts. The modeling of the combustor involves dividing the combustor into a number of reactors representing various combustion and near wall regions of the combustor. The calculations showed that the fuel reaction could proceed at a completely different rate depending on the conditions prevailing in each region of the combustor. The model results also indicated that at idle power mode the initial rate of NOx formation was high. However, due to the subsequent admission of air, no further addition to the NOx concentration was predicted at downstream locations. At high power levels, the fuel rich region near the combustor dome inhibits the formation of NOx. The admission of air in this case brings the fuel/air mixture close to the stoichiometric value causing a significant amount of NOx to form. The model calculations agreed quite well with the measured data of the combustor.Copyright © 1993 by ASME
The Pressure Dependence of the OH Radical Yield from Ozone-Alkene Reactions

The OH radical is the key oxidizing agent in the troposphere, and ozone−alkene reactions appear to be a significant and sometimes dominant source of new HOx radicals in urban and rural air. In this work, we report the first study of the pressure dependence of the OH radical yield for the ozonolysis of ethene, propene, 1-butene, trans-2-butene, and 2,3-dimethyl-2-butene over the range 20−760 Torr and of trans-3-hexene and cyclopentene over the range 200−760 Torr. Low-pressure experiments were performed in a long-path evacuable FTIR cell or a steady-state flow-tube reactor in series with a gas chromatograph/flame ionization detector and FTIR cell. We have also investigated the effect of adding SF6 at atmospheric pressure for ethene, 1-butene, and trans-2-butene, in a collapsible Teflon chamber. OH formation increased almost 3-fold for ethene at low pressures, from 0.22 ± 0.06 at 760 Torr to 0.61 ± 0.18 at 20 Torr, and increased somewhat for propene from 0.33 ± 0.07 at 760 Torr to 0.46 ± 0.11 at 20 Torr. A p...
Hydrocarbon Rocket Engines for Earth-to-Orbit Vehicles

The Space Shuttle has initiated a new era in Earth-to-orbit transportation and studies are now under way to assess the technology requirements for more advanced vehicles. Potential derivatives of the Space Shuttle and completely new vehicles might both benefit from advanced hydrocarbon engines, several versions of which were recently studied. In the present paper, selected single-stage vehicles have been compared using these engines. The results indicate that propane staged-combustion engines are attractive for this application. The potential effects of advanced engine materials are also shown. HE Space Shuttle has initiated a new era in Earth-to-orbit transportation, and the large number of payload reservations indicates that the system will be used to capacity. Many advantages of operating in space with the Shuttle have been hypothesized, such as satellite checkout and repair in orbit. Assembly of large space structures from the Shuttle is also being considered. Beyond the first few years of the Shuttle era, Earth-to-orbit traffic will grow to the point that vehicles beyond the Space Shuttle should be developed for a more efficient transportation system. Advanced orbit-transfer vehicles are being considered in several future systems studies. Even though the Space Shuttle era has just begun, the time to develop the technology for future vehicles is now. Derivatives of the Space Shuttle have been studied in the past,1 and a current study2 will provide additional insight into such derivatives. For the more distant future, completely new, fully reusable vehicles have been proposed as in Refs, 3-6. One of the more promising concepts that have been con- sidered for new vehicles is the single-stage, dual-fuel vehicle. Vertical launch and horizontal landing, which is the operational mode of the Space Shuttle, may provide the lowest risk. One of the most significant design concerns for such a concept is the aft center of gravity. This concern is somewhat alleviated by dual-fuel propulsion, and recent work on control-confi gured design indicates that vehicles can be controlled during return from orbit to the runway with center- of-gravity locations considerably aft of the current Shuttle limits.7 Previous studies have shown that advanced hydrocarbon liquid rocket engines would be beneficial to both Shuttle derivatives and advanced vehicles. Replacing the Shuttle solid rocket boosters with liquid-fueled boosters could reduce environmental concerns and operational costs. Although derivatives of the Space Shuttle Main Engine (SSME) could be used for such liquid-fueled boosters, advanced hydrocarbon engines would reduce operational costs more. Several ad- vanced hydrocarbon engines have been studied in the past for use with hydrogen-fueled engines for new Earth-to-orbit vehicles, and the results have indicated a significant advantage over hydrogen engines alone.l One of the findings that surfaced in previous studies is that
Implications of postcranial evidence for the origin of euprimates

Abstract Lemuriforms, Tarsius , anthropoids, adapids, and omomyids share numerous derived postcranial features which support monophyly of the Euprimates and indicate that the archaic primate to euprimate transition was marked by a striking reorganization of the skeleton presumably related to a transformation in locomotor behavior. Analysis of the tarsus indicates that the ancestral euprimate differed from its plesiadapiform progenitor in features related to its increased ability to leap and climb using a grasp based on an opposable hallux. Adapids share derived pedal features with the extant lemuriforms, supporting the monophyly of the Strepsirhini. Omomyids, Tarsius , and anthropoids have the primitive condition of these traits.
Carbon Nanotubes Activate Blood Platelets by Inducing Extracellular Ca2+ Influx Sensitive to Calcium Entry Inhibitors

To elucidate a mechanism of prothrombotic effects of carbon nanotubes (CNTs), we report here that multiwalled CNTs activate blood platelets by inducing extracellular Ca(2+) influx that could be inhibited by calcium channel blockers SKF 96365 and 2-APB. We also demonstrate platelet aggregating activity of different single-walled and multiwalled CNTs. In addition, we show that CNT-induced platelet activation is associated with a marked release of platelet membrane microparticles positive for the granular secretion markers CD62P and CD63.
Isolation of22Na for intense positron sources

A method of removing22Na from Al via distillation is investigated. Distillation is rapid (≈10 minutes) and nearly quantitative. When the distilled vapor is directed by a flow of He gas the deposit may be localized fairly well and easily recovered with water.
Fault-proximal stratigraphic record of episodic extension and oblique inversion, Bisbee basin, southwestern New Mexico, USA

Tectonic inversion models predict that stratigraphic thickening and local facies patterns adjacent to reactivated fault systems should record at least two phases of basin development: (1) initial extension-related subsidence and (2) subsequent shortening-induced uplift. In the central Peloncillo Mountains of southwestern New Mexico, thickness trends, distribution, and provenance of two major stratigraphic intervals on opposite sides of a northwest-striking reverse fault preserve a record of Early Cretaceous normal displacement and latest Cretaceous–Paleogene reverse displacement along the fault. The Aptian–Albian Bisbee Group thickens by a factor of three from the footwall to the hanging-wall block, and the Late Cretaceous?–Eocene Bobcat Hill Formation is preserved only in the footwall block. An initial episode of normal faulting resulted in thickening of upper Aptian–middle Albian, mixed siliciclastic and carbonate deposits and an up section change from coarse-grained deltas to shallow-marine depositional conditions. A second episode of normal faulting caused abrupt thickening of upper Albian, quartzose coastal-plain deposits across the fault. These faulting episodes record two events of extension that affected the northern rift shoulder of the Bisbee basin. The third faulting episode was oblique-slip, reverse reactivation of the fault and other related, former normal faults. Alluvial and pyroclastic deposits of the Bobcat Hill Formation record inversion of the Bisbee basin and development of an intermontane basin directly adjacent to the former rift basin. Inversion was coeval with latest Cretaceous–Paleogene shortening and magmatism. This offset history offers significant insight into extensional basin tectonics in the Early Cretaceous and permits rejection of models of long-term Mesozoic shortening and orogen migration during the Cretaceous. This paper also illustrates how episodes of fault reactivation modify, in very short distances (<10 km), regional patterns of subsidence, the distribution of sediment-source areas, and sedimentary depositional systems.
Approximate models of microsegregation with coarsening

Microsegregation refers to the processes of solute rejection and redistribution at the scale of the dendrite arm spaces in the mushy region of a solidifying alloy. A representative geometry for a microsegregation analysis is the half-arm spacing in a platelike morphology. Models of microsegregation are based on a solute balance within this domain. A recent review by Kraft and Chen covers the range of available models. Common assumptions used in modeling include a binary eutectic alloy; a fixed average composition, C{sub 0}; equilibrium at the solid-liquid interface; a constant partition coefficient k {lt} 1; and a straight liquidus line in the phase diagram. The two features of the solute balance that need to be included in a comprehensive model are the following. (1) The mass diffusion of the solute. Typically, the solute diffusion in the liquid is rapid, and, at each instant in time, a uniform distribution of solute, C{sub {ell}}(t), can be assumed. In the solid, however, diffusion is much slower and the solute balance needs to account for the so-called back-diffusion of solute into the solid. (2) Changes in morphology. As solidification proceeds, the arm spacing will coarsen. If the overall solute balance is maintained in the half-armmore » domain, this feature will dilute the solute in the liquid.« less
Computational Modeling of Beta-Fibrils

Beta-sheet protein fibrils have been associated with many important pathological conditions such as Alzheimer's disease and type II diabetes. These fibrils are also important in the emerging field of peptide drug delivery since fibrillation is one of the critical degradation pathways for this class of drug molecules. Moreover, these structures have bionanotechnological applications such as formation of bio-nano-tubular scaffolds. Rational design of anti-fibrillation drugs, stable formulation of peptide drug molecules and development of bionanotechnological fibril devices all depend on understanding the structure of these fibrils. Although structures for some of such fibrils are experimentally determined, there are many others for which no structure is available. Hence, a computational method to model the structure of beta-sheet rich fibrils will be very valuable. We have devised such a computational method by combining homology modelling and MD simulation. The process starts with homology modelling of the beta-sheet building blocks using an optimized alignment and modelling scheme. Using those building blocks higher structures of the fibril are constructed. Finally, MD simulations are used to refine the fibril model and validate its energetic stability. We demonstrate the validity of our method by reproducing the experimentally determined structure of a number of beta-sheet fibrils. We also present the structure of glucagon beta-fibril for which no experimental structure is available. Understanding the structure of glucagon fibril can help inhibiting its fibrillation which is a major obstacle facing glucagon drug delivery.
Effects of Thickness and Roughness Variations on the Abrasiveness of a Thin Boron Carbide Coating

Boron carbide (B4C) is well known for its high hardness and favorable wear resistant properties. In dry sliding wear contact, it polishes its mating surface and provides fatigue resistance to coated parts. Employing such run-in coatings demands a thorough understanding of the parameters which directly influence the changes that occur in the coating abrasiveness during the polishing process. In this study, the effects of the overall coating thickness, overall coating roughness, substrate roughness and substrate roughness orientation are examined in connection with abrasiveness. The coating thickness only influences the initial abrasiveness, whereas the coating roughness drastically affects the rate at which the abrasiveness decreases. Finally, no significant changes are observed in the abrasiveness due to substrate roughness or substrate roughness orientation effects. This work provides further insight into the design of a finite-life run-in coating.
Dry machining of aluminum-silicon alloy using polished CVD diamond-coated cutting tools inserts

Abstract In this research, we investigated the performance of polished chemical vapor deposited (CVD) diamond tool carbide inserts in comparison with unpolished CVD diamond coated carbide tool inserts in the dry turning of A390 aluminum–silicon hypereutectic alloy. The special emphasis is on exploring the role of machining parameters and cutting tool surface morphology on the aerosol generation. Global demand for high speed machining in combination with environmentally benign methods make diamond coated carbide tools an attractive candidate for dry machining. The results of this research demonstrate that CVD diamond-coated polished tools generate fewer particles, unlike conventional diamond tools (PCD and unpolished CVD), which cause the formation of respirable airborne particles during machining. Further, polished CVD diamond tool inserts improve tool life and reduce the cutting forces. Overall, in an important finding it is shown that polishing of tools provides a better opportunity for an environmentally benign dry machining along with improvement in machining outcome.
Population analyses of the vascular plant pathogen Verticillium dahliae detect recombination and transcontinental gene flow

The fungal pathogen Verticillium dahliae has resulted in significant losses in numerous crops in coastal California, but lettuce remained unaffected until the mid-1990s. Since then outbreaks have decimated entire fields, but the causes of this sudden susceptibility of lettuce remain elusive. The population structure of V. dahliae isolated from coastal California (n = 123) was investigated with 22 microsatellite markers, and compared with strains from tomato in central California (n = 60), spinach seed imported from Washington State and Northern Europe (n = 43), and ornamentals from Wisconsin (n = 17). No significant differentiation was measured among hosts in coastal California or with the spinach and Wisconsin ornamental sampling groups. In contrast, the tomato sampling group was significantly differentiated. Significant gene flow was measured among the various geographic and host sampling groups, with the exception of tomato. Evidence of recombination in V. dahliae was identified through gametic disequilibrium and an exceedingly high genotypic diversity. The high incidence of V. dahliae in spinach seed and high planting density of the crop are sources of recurrent gene flow into coastal California, and may be associated with the recent outbreaks in lettuce.
Pemetrexed and oxaliplatin for metastatic colorectal cancer: results of a phase I Mayo Cancer Center Research Consortium trial, MC0248.

Abstract Purpose Pemetrexed, an antifolate involved in purine and pyrimidine formation, is a potential alternative to fluoropyrimidines in the treatment of colorectal cancer. A phase I trial was performed to establish the maximum tolerated dose (MTD) of pemetrexed and oxaliplatin when B12 and folate supplementation is used. Patients and Methods Patients with metastatic colorectal cancer received folate (> 350 μg) daily and vitamin B12 (1000 μg) every 9 weeks starting 7 days before chemotherapy. Pemetrexed over 10 minutes and oxaliplatin over 2 hours were given every 3 weeks in escalating dose cohorts. Results Twenty-two patients were entered on 6 dose levels. The MTD was established at the highest dose level, pemetrexed 900 mg/m2 and oxaliplatin 130 mg/m2. Toxicities related to treatment at the MTD included grade 3 neutropenia and thrombocytopenia. For all dose levels combined, grade 3/4 toxicities included hematologic, neurologic, and gastrointestinal. Nine of 21 evaluable patients responded overall (response rate, 43%). The time to tumor progression was 11.9 months. Conclusion The MTD was determined to be pemetrexed 900 mg/m2 and oxaliplatin 130 mg/m2 every 21 days when folate and B12 supplementation are used. Because of the observed tolerability and activity of this regimen, further evaluation is warranted.
Cardiovascular effects of melanocortins

Melanocortins (MSH's) are three structurally related peptides derived from proopiomelanocortin. They regulate several physiologic functions including energy metabolism, appetite, and inflammation. Recent work in rodents has also identified important effects of MSH's, particularly γ-MSH, on sodium metabolism and blood pressure regulation. Normal rats and mice respond to a high sodium diet with an increase in the plasma concentration of γ-MSH, and remain normotensive, while those with genetic or pharmacologic γ-MSH deficiency become hypertensive on a high sodium diet. This hypertension is corrected by exogenous administration of the peptide. Mice lacking the γ-MSH receptor (the melanocortin 3 receptor, Mc3r) also become hypertensive on a high sodium diet but remain so when administered γ-MSH, and infusions of physiologic levels of the peptide stimulate urinary sodium excretion in normal rats and mice, but not in mice with deletion of Mc3r. The salt-sensitive hypertension in rodents with impaired γ-MSH signaling appears due to stimulation of noradrenergic activity, since plasma noradrenaline is increased and the hypertension is rapidly corrected with infusion of the α-adrenoceptor antagonist phentolamine. In contrast to the antihypertensive property of physiologic levels of γ-MSH, intravenous or intracerebroventricular injections of high levels of the peptide raise blood pressure. This occurs in mice lacking Mc3r, indicating an interaction with some other central receptor. Finally, the salt-sensitive hypertension in rodents with disruption of γ-MSH signaling is accompanied by insulin resistance, an observation which offers a new window into the study of the association of salt-sensitive hypertension with insulin resistance and type II diabetes.
pKa Perturbation in Genomic Hepatitis Delta Virus Ribozyme Catalysis Evidenced by Nucleotide Analogue Interference Mapping

The Hepatitis Delta Virus (HDV) ribozyme was the first RNA enzyme proposed to use a proton-transfer mechanism for catalysis. Previous biochemical evidence suggested that the genomic HDV ribozyme promotes cis-cleavage using cytosine 75 whose pK a is perturbed within the active site. Here we present further biochemical evidence for the involvement of C75 in proton transfer, as well as evidence to support a plausible mechanism for C75 pK a perturbation. Nucleotide analogue interference mapping (NAIM) experiments with C analogues having altered N3 pK a s demonstrate the importance of C75 ionization in the HDV cis-cleavage reaction. pH-dependent interference rescue with C analogues having enhanced N3 acidity indicates that C75 is the only cytidine residue that must be protonated for ribozyme activity. Furthermore, interference analysis with pseudoisocytidine, a charge-neutral mimic of a C with a protonated N3, shows a pattern consistent with proton transfer, possibly from the C75 N3 to the 5'-oxyanion leaving group during the cis-cleavage reaction. Strong pH-independent inhibition of ribozyme function also occurs at C75 with a C analogue that lacks the N4 amino group, implicating the exocyclic amine in critical interactions in the active site. Interactions with the amino group may play an important role in perturbing the C75 N3 pK a . Protonation of C41 has been proposed to be important for ribozyme activity; however, no interference at C41 was observed in this analogue series, which argues against a functional role for C41 protonation. These data support a model wherein C75 of the genomic HDV ribozyme acts as a general acid during its cis-cleavage reaction, and provide a glimpse into how RNAs, in a manner similar to protein enzymes, might employ local environmental electronic modulation to catalyze reactions.
Encapsulation and selectivity of sulfate with a furan-based hexaazamacrocyclic receptor in water

A furan-based hexaazamacrocycle encapsulates a sulfate anion in its cavity showing strong affinity and selectivity for sulfate in water over a wide range of inorganic anions. The DFT calculations demonstrate that the receptor provides binding sites as hydrogen bonding donors and electrostatic positive charges for the strong binding of sulfate.
Desert landforms at the kurkur oasis, egypt

ABSTRACT The Libyan Desert of the Kurkur area, west of Aswan, was primarily modeled by running water in late Tertiary and early Pleistocene times, and has been subsequently remodeled by wind. Analysis of the desert landforms thus sculptured under semiarid to hyperarid conditions shows that drainage characteristics, slope forms, and surficial materials are distinctive from those commonly associated with humid environments. Areas of smooth slopes and limited relief are dominant, and stream dissection is limited, with very coarse texture a characteristic. Steep, parallel rectilinear mid-slopes offset by sharp, angular breaks in gradient provide a bimodal slope distribution in gentle and steep categories. Lag, talus, and water-transported scree essentially replace the concept of the soil mantle. Alluvial and colluvial deposits are extensive even though thin and rarely activated. This example from Kurkur suggests that systematic studies of landform differences between arid and humid environments are both possi...
Current-voltage characteristics of Schottky barrier diodes with dynamic interfacial defect state occupancy

Schottky barrier diode theory conventionally assumes that the barrier height remains constant with the applied bias. However, high ideality factors and certain anomalous capacitance-voltage characteristics can only be explained by letting the barrier height vary with the applied voltage. Changes in the occupation of surface states have been inferred to be the cause of this change in barrier height, although the precise nature of these surface states has not yet been determined. This article examines the role of monoenergetic interfacial defect states whose occupancy is dynamically controlled by the local carrier densities, rather than by equilibrium conditions. Certain types of surface donor and acceptor states are shown to have a strong influence on the resulting current-voltage characteristics. The Al/GaAs(100) system is discussed in detail and experimental results are compared to this analytic model.
Development of a 50mm dual Flip Chip Plastic Land Grid Array package for server applications

For many years, the Flip Chip Plastic Ball Grid Array (FC-PBGA) has been the preferred packaging solution for microprocessors and high performance ASICs. IBM has developed a dual chip Flip Chip Plastic Land Grid Array (FC- PLGA) package to support low and mid range server solutions. This organic 50 mm times 50 mm lead reduced package solution uses a 6-4-6 build-up laminate with two large chips consisting of a processor (22 times 16 mm) and a memory cache (15 times 13 mm) in a single piece lid capping solution. In this paper, we will summarize development activities performed in order to achieve a reliable product while dissipating up to 200 Watts mostly from the microprocessor chip. One of the many key issues to overcome was the assurance of good package thermal stability with such large silicon area coverage over the flexible organic chip carrier. Special chip and module test vehicles were designed and fabricated in order to evaluate the mechanical, electrical, and thermal behaviour of the package post assembly and throughout stress testing. The assembly process development activities performed to support the desired application will be discussed in conjunction with mechanical modeling results. In addition, thermal data will be presented showing the positive results obtained as well as good correlation to the thermal and mechanical models.
NO x cycle and the tropospheric ozone isotope anomaly: an experimental investigation

Abstract. The oxygen isotope composition of nitrogen oxides (NOx) in the atmosphere is a useful tool for understanding the oxidation of NOx into nitric acid / nitrate in the atmosphere. A set of experiments was conducted to examine change in isotopic composition of NOx due to NOx–O2–O3 photochemical cycling. At low NOx / O2 mixing ratios, NOx became progressively and nearly equally enriched in 17O and 18O over time until it reached a steady state with Δ17O values of 39.3 ± 1.9‰ and δ18O values of 84.2 ± 4‰, relative to the isotopic composition of the initial O2 gas. As the mixing ratios were increased, the isotopic enrichments were suppressed by isotopic exchange between O atoms, O2, and NOx. A kinetic model was developed to simulate the observed data and it showed that the isotope effects occurring during O3 formation play a dominant role in controlling NOx isotopes and, in addition, secondary kinetic isotope effects or isotope exchange reactions are also important during NOx cycling. The data and model were consistent with previous studies which showed that the NO + O3 reactions occur mainly via the transfer of the terminal atoms of O3. The model predicts that under tropospheric concentrations of NOx and O3, the timescale of NOx–O3 isotopic equilibrium ranges from hours (for ppbv NOx / O2 mixing ratios) to days (for pptv mixing ratios) and yields steady state Δ17O and δ18O values of 45‰ and 117‰ respectively (relative to Vienna Standard Mean Ocean Water (VSMOW)) in both cases. Under atmospheric conditions when O3 has high concentrations, the equilibrium between NOx and O3 should occur rapidly (h) but this equilibrium cannot be reached during polar winters and/or nights if the NOx conversion to HNO3 is faster. The experimentally derived rate coefficients can be used to model the major NOx–O3 isotopologue reactions at various pressures and in isotope modeling of tropospheric nitrate.
Organizational disaster and organizational decay: the case of the National Aeronautics and Space Administration:

Organizational decay is a condition of generalized and systemic ineffective- ness. It develops when an organization shifts its activities from coping with reality to presenting a dramatization of its own ideal character. In the decadent organization, flawed decision making of the sort that leads to disaster is normal activity, not an aberration. Three aspects of the development of organizational decay are illustrated in the case of the US National Aeronautics and Space Administration. They are (1) the institutionalization of the fiction, (2) per sonnel changes in parallel with the institutionalization of the fiction, and (3) the narcissistic loss of reality among management.
Multiassignment for tracking a large number of overlapping objects

In this paper we present a new technique for data association using multiassignment for tracking a large number of closely spaced (and overlapping) objects. The algorithm is illustrated on a biomedical problem, namely the tracking of a group of fibroblast (tissue) cells from an image sequence, which motivated this work. The algorithm presents a novel iterated approach to multiassignment using successive one-to-one assignments of decreasing size with modified costs. The cost functions, which are adjusted depending on the 'depth' of the current assignment level and on the tracking results, are derived. The resulting assignments are used to form, maintain and terminate tracks with a modified version of the probabilistic data association filter, which can handle the contention for a single measurement among multiple tracks in addition to the association of multiple measurements to a single track. Estimation results are given and compared with those of the standard 2-dimensional one-to-one assignment algorithm. It is shown that iterated multiassignment results in superior measurement-to- track association.
Interval and Pitch Recognition in and out of Immediate Context

Samples of 24 and 12 college music majors were given tests of interval recognition and pitch recognition to investigate specific context effects. Absolute-pitch individuals were excluded. Conditions were: (1) single tones (pitch recognition), (2) isolated as cending intervals terminating in the same tones, (3) the same intervals, preceded by a distractor tone, and (4) the same intervals followed by a distractor tone. Conditions 3a and 4a were also run, with the distance of the distractor tone from its adjacent tone changed from a major third to a minor third. Recognition of the minor third, tritone, and minor and major sixths was enhanced by condition 4, as compared with the control condition 2. In condition 3 incorrect responses overestimated the targets, whereas in condition 4 targets were underestimated. There was no evidence that pitch recognition ability in nonabsolute pitch subjects aids interval recognition.
Regulation of Glycine Decarboxylase and l-Serine Hydroxymethyltransferase Activities by Glyoxylate in Tobacco Leaf Mitochondrial Preparations

Glyoxylate at a concentration of 10 millimolar caused 50% inhibition of decarboxylation of 20 millimolar [1- 14 C]glycine and accompanying synthesis of serine in a mitochondria-enriched preparation from tobacco ( Nicotiana tabacum var. John Williams Broadleaf) leaves. None of the other compounds tested including formate, acetate, oxalate, aspartate, and glutamate appreciably affected activity. Occasional inhibition produced by glycolate may have resulted from residual glycolate oxidase in these preparations. Added glyoxylate was not converted to glycine in these preparations and about 98% of it could be recovered at the end of the reaction. Hence, the observed inhibition by glyoxylate did not result from dilution of radioactivity in the substrate. Glyoxylate also regulated synthesis of HCHO from l-serine catalyzed by l-serine hydroxymethyltransferase in mitochondrial preparations. Control of this enzyme activity by glyoxylate was complex and was characterized by enhancement of activity at low glyoxylate concentrations (less than 10 millimolar) and inhibition by concentrations generally above 10 millimolar. These results define potential sites of biochemical regulation of important steps in the pathway of photorespiratory carbon flow and are considered in the light of other observations of effects of exogenous glyoxylate on photorespiration in leaf tissue.
Thalidomide as replacement for steroids in immunosuppression after lung transplantation

Steroids have been implicated in postoperative complications after lung transplantation: infections, delayed wound healing, and poor bronchial anastomotic healing. Thalidomide (alpha-phthalimidoglutarimide), a sedative drug with known immunomodulatory properties, was used to replace corticosteroids after canine lung transplantation. Fifteen mongrel dogs underwent single-lung transplantation: group I (n = 5) received cyclosporin A (20 mg/kg twice a day), azathioprine (2.5 mg/kg once a day), and thalidomide (50 mg/kg twice a day). Group II (n = 5) received standard immunosuppression of cyclosporin A (20 mg/kg twice a day), azathioprine (2.5 mg/kg once a day), and prednisone (2 mg/kg once a day), and group III (n = 5) received cyclosporin A (10 mg/kg twice a day), azathioprine (2.5 mg/kg once a day), and thalidomide (50 mg/kg twice a day). Open lung biopsy and bronchoscopy were performed weekly until sacrifice on day 28. Serum thalidomide and cyclosporin A levels were followed up weekly. Group I showed essentially no rejection until week 2 and minimal rejection (grade 1) until day 28. Group II had moderate rejection (grade 2) of the graft at all time points. Group III animals had moderate to severe rejection (grades 3 to 4) after 21 days (p < 0.05 for group I versus groups II and III). The number of clinically evident episodes of pneumonia was also significantly lower in group I than in groups II and III (p < 0.05). We conclude that thalidomide appears to replace corticosteroids effectively in early postoperative immunosuppression after lung transplantation and is associated with a decreased incidence of pneumonia.(ABSTRACT TRUNCATED AT 250 WORDS)
Interannual variation of atmospheric mass and the southern oscillation

Two reanalysis datasets, one generated by the Goddard Laboratory for Atmospheres for 1982–1993 and the other generated by the National Centers for Environmental Prediction for 1982–1995, are used to examine the relationship between the Southern Oscillation (SO) and the interannual variation of atmospheric mass. Both reanalyses show that atmospheric mass increases (decreases) during the positive (negative) SO phase. Atmospheric mass consists of dry air and moisture. Since dry mass is conserved, the interannual variation of atmospheric mass results from the variation of water vapor pressure. Thus, global atmospheric hydrological processes are analyzed to illustrate how the SO affects the interannual variation of atmospheric mass. During the positive (negative) SO phase, water vapor is converged (diverged) toward (out of) the central-eastern tropical Pacific [where sea surface temperatures (SSTs) are higher (lower) than normal] to maintain (suppress) cumulus convection in that area. An anomalous east-west Walker circulation straddling the Dateline is driven by the anomalous cumulus convection in this region to create positive (negative) surface pressure anomalies over the western tropical Pacific-Indian Ocean, which result in an increase (decrease) in atmospheric mass. DOI: 10.1034/j.1600-0870.1997.t01-4-00003.x
Kinetic Analysis of the Conjugation of Ubiquitin to Picornavirus 3C Proteases Catalyzed by the Mammalian Ubiquitin-protein Ligase E3α

Abstract The 3C proteases of the encephalomyocarditis virus and the hepatitis A virus are both type III substrates for the mammalian ubiquitin-protein ligase E3α. The conjugation of ubiquitin to these proteins requires internal ten-amino acid-long protein destruction signal sequences. To evaluate how these destruction signals modulate interactions that must occur between E3α and the 3C proteases, we have kinetically analyzed the formation of ubiquitin-3C protease conjugates in a reconstituted system of purified E1, HsUbc2b/E214Kb, and human E3α. Our measurements show that the encephalomyocarditis virus 3C protease is ubiquitinated in this system with K m = 42 ± 11 μm and V max = 0.051 ± 0.01 pmol/min whereas the parameters for the ubiquitination of the hepatitis A virus 3C protease are K m = 20 ± 5 μm and V max = 0.018 ± 0.003 pmol/min. Mutations in the destruction signal sequences resulted in changes in the rate at which E3α conjugates ubiquitin to the altered 3C protease proteins. The K m andV max values for these reactions change proportionally in the same direction. These results suggest differences in rates of conjugation of ubiquitin to 3C proteases are primarily ak cat effect. Replacing specific encephalomyocarditis virus 3C protease lysine residues with arginine residues was found to increase, rather than decrease, the rate of ubiquitin conjugation, and the K m andV max values for these reactions are both higher than for the wild type protein. The ability of E3α to catalyze the conjugation of ubiquitin to both 3C proteases was found to be inhibited by lysylalanine and phenylalanylalanine, demonstrating that the same sites on E3α that bind destabilizing N-terminal amino acids in type I and II substrates also interact with the 3C proteases.
Vertical Ramus Osteotomy Allows Exposure of the Distal Internal Carotid Artery to the Base of the Skull

Exposure of the distal internal carotid artery (ICA) above the level of the second cervical vertebra can be difficult and often require maneuvers such as division of the digastric muscle or mandibular subluxation. These techniques increase exposure but may not provide adequate access. We report a series of eight cases in which vertical division of the mandibular ramus provided access of the ICA up to the base of the skull. Over the last 10 years, eight patients underwent vertical ramus osteotomy (VRO) to aid in distal ICA exposure. Preoperative arteriography revealed ICA lesions within 1.5 cm of the skull base. Indications for surgery were compelling and included gunshot wounds to zone III of the neck (n = 2), transient ischemic attack (n = 2), and preocclusive stenosis (n = 4). VRO was performed through a standard vertical neck incision and was created from the depth of the sigmoid notch to the angle of the mandible after elevating the masseter muscle from the bone. Miniature titanium plates were used to reapproximate the mandible after endarterectomy (n = 5), bypass (n = 2), or arterial repair (n = 1). We found that VRO provides reliable exposure of the distal ICA up to the base of the skull. Unlike mandibular subluxation, it requires no pre-incision preparation, thus mandibulotomy can be performed after carotid artery dissection has begun, and may even be avoided. VRO is especially useful when carotid artery pathology unexpectedly extends beyond the usual field of exposure. Work on the carotid artery at the skull base is associated with significant complications and should be reserved for compelling indications.
Robust uncorrelated bit extraction methodologies for wireless sensors

This paper presents novel methodologies which allow robust secret key extraction from radio channel measurements which suffer from real-world non-reciprocities and a priori unknown fading statistics. These methodologies have low computational complexity, automatically adapt to differences in transmitter and receiver hardware, fading distribution and temporal correlations of the fading signal to produce secret keys with uncorrelated bits. Moreover, the introduced method produces secret key bits at a higher rate than has previously been reported. We validate the method using extensive measurements between TelosB wireless sensors.
Presenilin: Running with Scissors in the Membrane

The presenilin-containing γ-secretase complex is an unusual membrane-embedded protease that processes a wide variety of integral membrane proteins, clearing protein stubs from the lipid bilayer and participating in critical signaling pathways. The protease is also central to Alzheimer's disease and certain cancers and is therefore an important therapeutic target. Here we highlight recent progress in deciphering the role of presenilin/γ-secretase in biology and medicine and pose key questions for future study.
RDMA-Based Job Migration Framework for MPI over InfiniBand

Coordinated checkpoint and recovery is a common approach to achieve fault tolerance on large-scale systems. The traditional mechanism dumps the process image to a local disk or a central storage area of all the processes involved in the parallel job. When a failure occurs, the processes are restarted and restored to the latest checkpoint image. However, this kind of approach is unable to provide the scalability required by increasingly large-sized jobs, since it puts heavy I/O burden on the storage subsystem, and resubmitting a job during restart phase incurs lengthy queuing delay. In this paper, we enhance the fault tolerance of MVAPICH2, an open-source high performance MPI-2 implementation, by using a proactive job migration scheme. Instead of checkpointing all the processes of the job and saving their process images to a stable storage, we transfer the processes running on a health-deteriorating node to a healthy spare node, and resume these processes from the spare node. RDMA-based process image transmission is designed to take advantage of high performance communication in InfiniBand. Experimental results show that the Job Migration scheme can achieve a speedup of 4.49 times over the Checkpoint/Restart scheme to handle a node failure for a 64-process application running on 8 compute nodes. To the best of our knowledge, this is the first such job migration design for InfiniBand-based clusters.