cssi/SciSciGPT-SciSciNet huggingface dataset:
Current status of new drugs and multidisciplinary approaches in patients with carcinoma of the esophagus

The incidence of distal esophageal adenocarcinoma and primary proximal gastric carcinoma has increased substantially in the past 15 years, particularly in North America and in some European countries. Patients with curatively resected cancer consistently have a 10 to 20% 5-year survival rate. Radiation therapy alone should not be recommended. Based on the Radiation Therapy Oncology Group/Eastern Cooperative Oncology Group (ECOG) trial in patients with predominantly squamous cell carcinoma, chemoradiotherapy (fluorouracil [5-FU]/cisplatin + 50 Gy of radiotherapy) has been shown to be superior in this setting. The most active single agents against squamous cell carcinoma are cisplatin, 5-FU, bleomycin, paclitaxel, mitomycin, mitoguazone, vinorelbine, and methotrexate. The most active agents against adenocarcinoma include paclitaxel and probably mitomycin, mitoguazone, and cisplatin. To my knowledge, there is currently no effective postoperative adjuvant therapy (chemotherapy, radiation therapy, or both). Evidence that preoperative therapy can prolong survival of patients with potentially resectable carcinoma of the esophagus is lacking. Preoperative chemoradiotherapy can result in an approximately 25% complete pathologic response of the primary tumor. Preoperative chemoradiotherapy, however, results in substantial morbidity and even mortality. A recent single-institution, randomized study comparing surgery alone with preoperative 5-FU/cisplatin/vinblastine and concurrent radiotherapy demonstrated no difference in median survival (18 months). Nevertheless, combined-modality therapy holds promise. Multiple combined-modality strategies have been formulated and will be investigated in the next few years.
The effect of intraalveolar fluid on lung bacterial clearance.

Appropriate animal models of lung bacterial clearance are difficult to establish in part because our current understanding of the pathogenesis of human pneumonia is imprecise. If all available models produced similar data their relevance to human infection would be strengthened. To assess consistency between two such models, we studied the effects of pulmonary edema and intratracheally injected protein on the pulmonary clearance of either aerosolized or intratracheally injectedStaphylococcus aureus orStreptococcus pneumoniae. Intraalveolar fluid, whether produced by increasing pulmonary capillary permeability or by intratracheal inoculation of bacteria, impaired lung bacterial clearance. This impairment varied with the organism employed. Proteinaceous intraalveolar fluid does not impair clearance by supporting bacterial multiplication and may enhance clearance of some organisms. Our results suggest that animal models of human lung infection are not easily constructed, remain problematic, and, at best, are only valid for the specific conditions of the model.
Students' involvement in group experiences and connections to leadership development

This chapter introduces a taxonomy reflecting patterns of involvement in student clubs and organizations during college and its relationship to leadership development. Insights for better understanding college student engagement, along with applications associated with institutional research, are explored.
Memory, monitoring, and control in the attainment of memory accuracy

Abstract Three experiments assessed people’s ability to strategically regulate memory accuracy in free report. Older adults were substantially less accurate than young adults in free report cued recall. Both older and younger adults made gains in memory accuracy from forced report to free report, but older adults did so at the expense of greater losses in quantity correct. This pattern of gains in accuracy at the cost of losses in quantity was mediated by the level of memory monitoring, and older adults showed less correspondence between their confidence judgments and the accuracy of their responses. When young adults encoded items with full vs. divided attention, the resulting differences in retention set off a cascade of effects including poorer memory monitoring and, ultimately, lower accuracy in free report. We suggest that older adults’ problems with memory monitoring and memory accuracy stem from impairments in their ability to recollect details of events.
Mast cells: Versatile regulators of inflammation, tissue remodeling, host defense and homeostasis

The possible roles of mast cells in heath and disease have been a topic of interest for over 125 years. Many adaptive or pathological processes affecting the skin or other anatomical sites have been associated with morphological evidence of mast cell activation, and/or with changes in mast cell numbers or phenotype. Such observations, taken together with the known functions of the diverse mediators, cytokines and growth factors which can be secreted by mast cells, have suggested many potential functions for mast cells in health and disease. Definitively identifying the importance of mast cells in biological responses in humans is difficult. However, mutant mice which are profoundly mast cell-deficient, especially those which can undergo engraftment with wild-type or genetically altered mast cells, provide an opportunity to investigate the importance of mast cells, and specific mast cell functions or products, in various adaptive or pathological responses in mice. Such work has shown that mast cells can significantly influence multiple features of inflammatory or immune responses, through diverse effects that can either promote or, surprisingly, suppress, aspects of these responses. Through such functions, mast cells can significantly influence inflammation, tissue remodeling, host defense and homeostasis.
Photoelectron branching ratios with a cylindrical mirror energy analyzer

Abstract A cylindrical mirror photoelectron energy analyzer suitable for measuring photoelectron branching ratios is described. The analyzer incorporates a pre-retarding/ accelerating system. This configuration is shown to have advantages over a conventional mirror analyzer in reduced pressure-sensitive scattering effects which can effect the accuracy of the branching ratios, and in increased sensitivity to low energy electrons. The electron collecting efficiency of the analyzer for a number of operating modes is given.
Fluorescence Lifetime Imaging with Near-Field Scanning Optical Microscopy

Near-field scanning optical microscopy (NSOM) is a high-resolution scanning probe technique capable of obtaining simultaneous optical and topographic images with spatial resolution of tens of nanometers. We have integrated time-correlated single-photon counting and NSOM to obtain images of fluorescence lifetimes with high spatial resolution. The technique can be used to measure either full fluorescence lifetime decays at individual spots with a spatial resolution of <100 nm or NSOM fluorescence images using fluorescence lifetime as a contrast mechanism. For imaging, a pulsed Ti:sapphire laser was used for sample excitation and fluorescent photons were time correlated and sorted into two time delay bins. The intensity in these bins can be used to estimate the fluorescence lifetime at each pixel in the image. The technique is demonstrated on thin films of poly(9,9'-dioctylfluorene) (PDOF). The fluorescence of PDOF is the results of both inter- and intrapolymer emitting species that can be easily distinguished in the time domain. Fluorescence lifetime imaging with near-field scanning optical microscopy demonstrates how photochemical degradation of the polymer leads to a quenching of short-delay intrachain emission and an increase in the long-delay photons associated with interpolymer emitting species. The images also show how intra- and interpolymer species are uniformly distributed in the films.
The initial teaching alphabet and educationally sub-normal children.

SUMMARY The results of using the Initial Teaching Alphabet (i.t.a.) with educationally subnormal (ESN) children are considered in the light of comments by 25 head teachers of esn schools who have been using i.t.a. The results are generally encouraging. The pupils' motivation and self-confidence is often improved, and some measurable improvement in reading standards is reported. RESUME Les resultats de l'utilisation de l'alphabet specialise (Initial Teaching Alphabet ou i.t.a.) dans l'education des enfants anormaux sont etudies a la lumiere des commentaires faits par 25 directeurs d'ecoles speciales pour enfants arrieres, qui ont utilise l'i.t.a. Les resultats sont en general encourageants. L'ardeur au travail des enfants et leur confiance en soi sont souvent ameliorees, et on rapporte des progres objectivement appreciables dans la qualite de la lecture. Note complementaire: L'i.t.a. est un alphabet special sans equivalent francais, qui evite la pronunciation variee pour la meme lettre. Chaque signe graphique correspond a un son et un seul.
Ion-pairing in aqueous CaCl2 and RbBr solutions: Simultaneous structural refinement of XAFS and XRD data

We present a new methodology involving the simultaneous refinement of both x-ray absorption and x-ray diffraction spectra (x-ray absorption/diffraction structural refinement, XADSR) to study the hydration and ion pair structure of CaCl2 and RbBr salts in concentrated aqueous solutions. The XADSR method combines the x-ray absorption fine structure (XAFS) spectral analysis of both the cation and anion as a probe of their short-range structure with an x-ray diffraction (XRD) spectral analysis as a probe of the global structural. Together they deliver a comprehensive picture of the cation and anion hydration, the contact ion pair (CIP) structure, and the solvent-separated ion pair (SSIP) structure. XADSR analysis of 6.0 m aqueous CaCl2 reveals that there are ∼0.26 Ca2+-Cl− CIP's separated by about 2.71 A, while there are 3.4 SSIP's separated by about 4.98 A. In contrast XADSR analysis of 6 m aqueous RbBr yields about 0.7 pair CIP at a bond length of 3.51 A. The present work demonstrates a new approach for a direct co-refinement of XRD and XAFS spectra in a simple and reliable fashion, opening new opportunities for analysis in various disordered and crystalline systems.
Silver polyvinyl pyrrolidone nanoparticles exhibit a capsular polysaccharide influenced bactericidal effect against Streptococcus pneumoniae

Streptococcus pneumoniae remains a leading cause of morbidity and mortality worldwide. The highly adaptive nature of S. pneumoniae exemplifies the need for next generation antimicrobials designed to avoid high level resistance. Metal based nanomaterials fit this criterion. Our study examined the antimicrobial activity of gold nanospheres (AuNP), silver coated polyvinyl pyrrolidone (AgPVP), and titanium dioxide (TiO2) against various serotypes of S. pneumoniae. Twenty nanometer spherical AgPVP demonstrated the highest level of killing among the tested materials. AgPVP (0.6 mg/mL) was able to kill pneumococcal serotypes 2, 3, 4, and 19F within 4 hours of exposure. Detailed analysis of cultures during exposure to AgPVP showed that both the metal ions and the solid nanoparticles participate in the killing of the pneumococcus. The bactericidal effect of AgPVP was lessened in the absence of the pneumococcal capsular polysaccharide. Capsule negative strains, JD908 and RX1, were only susceptible to AgPVP at concentrations at least 33% higher than their respective capsule expressing counterparts. These findings suggest that mechanisms of killing used by nanomaterials are not serotype dependent and that the capsular polysaccharide participates in the inhibition. In the near future these mechanisms will be examined as targets for novel antimicrobials.
PARTICIPANT OBSERVATION AS A TECHNIQUE IN OBSERVING DECISION-MAKING1

Summary PARTICIPANT OBSERVATION AS A TECHNIQUE IN OBSERVING DECISION MAKING Three types of participant observation are discussed. Examples from the literature are reviewed to establish the practicability and the validity of three techniques, namely participation by (1) assuming an active function within the system being observed, (2) being a more passive observer, and (3) obtaining the participation of subjects in laboratory experiments. All three types can have their place among the techniques of a modern social science research worker. They are of different relevance and importance to different research problems, and there is a difference in the costs involved in using them. Resume OBSERVATION PARTICIPANTE COMME TECHNIQUE D'OBSERVATION DE LA PRISE DE DECISION Cet article presente et critique trois types d'observation-participation. l'auteur, a l'aide d'exemples bibliographiques, montre le caractere pratique et la validite des techniques proposees, c'est-a-dire la participation (1) par l'exercice d'une fonction effective dans le systeme observe, (2) un statut d'observation plus passif et enfin (3) l' adhesion des membres du groupe a des experiences. Ces trois types peuvent avoir leur place parmi les techniques de travail d'un chercheur moderne en sciences sociales. Leur degre de pertinence est variable en fonction des differents problemes de recherche, ainsi que leur couts. Zusammenfassung TEILNEHMENDE BEOBACHTUNG ALS TECHNIK DER BEOBACHTUNG DES ENTSC H EI DU N GS PROZESSES Drei Typen teilnehmender Beobachtung werden diskutiert. Beispiele aus der Literatur werden herangezogen, um die Brauchbarkeit und Gultigkeit der vorgeschlagenen Techniken 2u beweisen. Diese sind: 1) Teilnahme durch Obernahme einer aktiven Funktion innerhalb des zu beobachtenden Systems, 2) eine mehr passive Beobachtung, und 3) Teilnahme der Betroffenen an Laboratoriumsexperimenten. Alle diese Typen konnen ihren Platz unter den Techniken eines modernen soziologischen Forschers haben. Sie sind von unter-schiedlicher Relevanz und Bedeutung fur die einzelnen Forschungs-probleme und ihre Benutzung verursacht unterschiedliche Kosten.
Architectural Nucleoporins Nup157/170 and Nup133 Are Structurally Related and Descend from a Second Ancestral Element

The nuclear pore complex (NPC) constitutes one of the largest protein assemblies in the eukaryotic cell and forms the exclusive gateway to the nucleus. The stable, ∼15–20-MDa scaffold ring of the NPC is built from two multiprotein complexes arranged around a central 8-fold axis. Here we present crystal structures of two large architectural units, yNup170979–1502 and hNup107658–925·hNup133517–1156, each a constituent of one of the two multiprotein complexes. Conservation of domain arrangement and of tertiary structure suggests that Nup157/170 and Nup133 derived from a common ancestor. Together with the previously established ancestral coatomer element (ACE1), these two elements constitute the major α-helical building blocks of the NPC scaffold and define its branched, lattice-like architecture, similar to vesicle coats like COPII. We hypothesize that the extant NPC evolved early during eukaryotic evolution from a rudimentary structure composed of several identical copies of a few ancestral elements, later diversified and specified by gene duplication.
Lung injury and the cinnamon challenge: college students should beware this Internet dare

A recent article in Pediatrics warns against inhaling cinnamon powder and cites experiments that demonstrated chronic inflammation and fibrotic changes to the pulmonary tissue of rats forced to inhale cinnamon powder, and was written in response to the growing popularity of the cinnamon challenge.1 The cinnamon challenge has existed for nearly a decade.2 This dare consists of consuming one tablespoon of cinnamon powder within one minute without drinking any fluids.3 The cinnamon challenge has become more popular among teenagers and young adults over the past four years.2 According to the American Association of Poison Control Centers (AAPCC), the number of calls to poison control centers concerning teenagers ages 13 to 19 who had undertaken the cinnamon challenge increased from 51 in 2011 to 222 in 2012. 4 In 2013, from January 1 to July 31, 37 such exposures were reported to poison control centers. 4 Not all persons who intentionally abuse or misuse cinnamon powder will need medical attention. Of the 122 calls classified as “intentional misuse or abuse” during the first three months of 2012, 30 required medical attention. 5 However, episodes in which medical attention is warranted may be underreported. Cinnamon is a caustic powder composed of cellulose fibers, which neither dissolve nor biodegrade in the lungs.1 The powder quickly dries out the mouth, which makes swallowing the powder very difficult. Coughing and burning sensations in the mouth, nose, and throat ensue. More serious symptoms include vomiting, epistaxis, and chest tightness1 and even atelectasis.6 Furthermore, the AAPCC warns that teenager with asthma or other pre-existing respiratory problems are at greater risk for developing respiratory distress from the cinnamon challenge.5 General internists and family practitioners who provide on-campus outpatient services to college students might encounter students with respiratory problems secondary to participating in the cinnamon challenge. Peer pressure is an appreciable factor among both children and young adults concerning participation in the cinnamon challenge.1 College students might undertake the challenge as part of their initiation into a student-led organization. Persons with an allergy to cinnamon or a pre-existing respiratory condition are encouraged to disclose their condition to friends or acquaintances who participate in the cinnamon challenge so that they are less likely to be pressured into following suit. In conclusion, college students are a population at risk for respiratory complications secondary to cinnamon toxicity. Educational efforts that highlight the dangers of the cinnamon challenge should be implemented on college campuses in addition to middle school, junior high school, and high school campuses. This Internet dare is not a concern just for pediatricians, but also for general internists, family practitioners, and pulmonologists.
Identification of transcriptive and replicative intermediates in Sendai virus-infected cells.

Abstract Partially ribonuclease-resistant RNA complexes elicited by Sendai virus infection were separated by rate zonal centrifugation and their metabolic and chemical properties were examined. Complexes sedimenting at about 24 S behaved like replicative intermediates involved in generating 50 S genomic viral RNA. A heterogeneous group of complexes sedimenting at 28 to 60 S appeared to be transcriptive intermediates, containing 50 S genomic RNA templates and 18 S complementary RNA products. In cells infected with mixtures of standard virus and incomplete virus, another group of RNA complexes, sedimenting at about 16 S, was observed. These structures contained chiefly complementary RNA strands and therefore may be predominantly transcriptive intermediates specified by the 19 and 24 S RNA species in incomplete virions.
Overlapping community detection using a community optimized graph swarm

Detection of communities within social networks is a nontrivial problem. Allowing communities to overlap—i.e. nodes can belong to more than one community simultaneously—further complicates the problem. Nevertheless, people do belong to multiple social groups simultaneously and being able to detect overlapping communities is an important step into being able to understand and analyze social networks. A common practice in community detection (clustering) is to view the network (graph) as a whole and have a central control process determine how nodes are clustered. That central control, we believe, is a limitation to performance. In our previous work, we showed that the individual’s view of his or hers social groups could be aggregated to produce communities. In this paper, we propose a unique approach to community detection that combines the individual’s view of a community, not having the view the graph as a whole, with swarm intelligence as a means of removing the central control mechanism. Our approach offers a community detection solution that finds overlapping communities while running in O(n log 2 n) time.
Interactive kiosks and their effects on services marketing: a call for further research

Abstract This paper explores the effects of interactive kiosks on consumer behavior and buying decisions. The authors suggest that this emerging technology will influence how retailers distribute their goods and services to consumers. It suggests that kiosk technology can standardize information and thereby enhance perceived service quality. Current uses of interactive kiosks and future research opportunities are provided.
The role of repeat transesophageal echocardiography in patients without atrial thrombus prior to cardioversion or ablation.

Background Cardioversion (CV) and radiofrequency catheter ablation (RFA) are often used to restore sinus rhythm in patients with atrial fibrillation (AF). These procedures are associated with a risk for stroke. The use of transesophageal echocardiography (TEE) to guide the management of AF is a validated strategy for patients in whom CV is planned, as well patients before RFA. For patients in whom the initial procedure fails, repeat TEE is often performed before repeat CV or RFA. The aim of this study was to test the hypothesis that patients with initial negative results on TEE would be unlikely to have thrombi detected on subsequent TEE and thus may avoid repeat procedures. Methods A total of 2,999 patients with AF were identified via retrospective review who had undergone TEE before CV or RFA, and 418 of these individuals underwent repeat TEE. After excluding patients who underwent repeat TEE >365 days from the initial study ( n = 135) and those with thrombi on initial TEE ( n = 20), 263 patients who had underwent two or more examinations were identified and analyzed. Results Of 263 eligible patients, two (0.8%; 95% confidence interval, 0.21–2.7%) had thrombi on subsequent TEE. Conclusions Fewer than 1% of patients with AF with negative results on baseline TEE had thrombi detected on repeat TEE before subsequent CV or RFA. Thus, it may be possible to selectively screen patients to identify those at low risk for developing thrombi subsequent to negative results on initial TEE, especially if patients are in sinus rhythm. These results suggest the need for a prospective trial to definitively answer the question regarding repeat TEE in low-risk patients.
Reescritura del pasado en El abrecartas de Vicente Molina Foix: una reconstrucción personalizada de la historia española

Past events can be altered. History gets rewritten. Well, we've just found that this applies to the real world too…. Maybe the real history of the world is changing constantly? And why? Because his...
Hyperbaric oxygen in the treatment of volvulus of the midgut: An experimental study

Abstract Volvulus of the midgut is a severe experimental preparation in the rat, most of the control animals dying even though the volvulus was present less than 3 hours. In 122 rats volvulus of the midgut was produced and untwisted 1 to 3 hours later. Eighty-eight animals had bowel wall infarction varying from moderate to very severe, 45 of which were exposed to 100 per cent oxygen at 3 At. A. for 1 hour. In the hyperbaric oxygen treated group, 20 (44 per cent) survived. In the control group, 7 (16 per cent) survived. When only the 75 animals with extensive infarction are considered, the survival rate for the hyperbaric oxygen treated animals in 35 per cent against 2.7 per cent for the controls.
Interpretation of Chemical Analyses of Clays

As a means of distinguishing between the broad groups of flay minerals, chemical analysis may be a valuable supplement to other methods, but rarely will it remove the necessity for other methods, X-ray analysis in particular. The two- and three-layer clay minerals may be distinguished by the SiO2 · Al2O3 ratio or SiO2 · sesquioxide ratio, but these ratios do not provide criteria for dividing either class. Among the three-layer clays, which embrace montmorillonite, nontronite, and the diverse hydrous micas, non-exchangeable K is a better criterion. It seems probable that montmorillonite, as found in bentonite deposits, does not contain significant amounts of non-exchangeable K, whereas all known hydrous micas contain significant, although widely variable, amounts of non-exchangeable K.
Parathyroid hormone is associated with biomarkers of insulin resistance and inflammation, independent of vitamin D status, in obese adolescents

Abstract Background: 25-Hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH) have been shown to correlate with several markers of metabolic syndrome in adult populations. We evaluated the relationship between circulating intact parathyroid hormone (iPTH) and 25(OH)D and indices of metabolic syndrome in obese adolescents. Methods: Body mass index (BMI), body composition, 25(OH)D, iPTH, fasting lipids, glucose, high-sensitivity C-reactive protein (hsCRP), glycosylated hemoglobin (HbA1c), insulin, and the homeostatic model assessment for insulin resistance (HOMA-IR) were evaluated in 133 obese adolescents. Results: Vitamin D deficiency [25(OH)D <50 nmol/L] was present in 45.1% of all patients, with higher prevalence in African-American (AA) and Hispanic (H) than Caucasian (C) subgroups (63.9% and 56.4% vs. 25.9%; P<0.001). iPTH and 25(OH)D were inversely correlated (r=−0.75; P<0.0001), with AA displaying a higher iPTH: 25(OH)D ratio than H and C subgroups (P<0.05). Whereas fat mass (FM) was negatively co...
Machining of terahertz split-block waveguides with micrometer precision

Evolutionary improvements in tooling and techniques are allowing increasingly complicated waveguide circuits to be fabricated with conventional end-mill machining at frequencies ranging from millimeter-wavelengths up to several terahertz. Machining precision is now approaching the limits of what can be measured with an optical microscope, with the measured dimensions of the highest-precision components typically within 2 mum of the nominal design values. We summarize the capabilities of the Space Instruments Shop at JPL and show examples of recently machined components.
IMMUNOGLOBULIN IN THE TREATMENT OF ANTIBIOTIC RESISTANT BACTERIA 58

Antibiotic resistant bacteria are increasing worldwide. Multi-drug resistant streptococci (such as pneumococci) and staphylococci re now common. Some enterococcal strains have become resistant to all effective antimicrobial agents including vancomycin. Antibodies may be useful to prevent infections caused by resistant bacteria and may be useful as adjunctive treatment with antibiotics especially when organisms are resistant to antibiotics. Immunoglobulin can act at several sites to block bacterial invasion and eradicate infection. Antistreptococcal antibodies have been shown to promote phagocytosis and enhance clearance of bacteria from the blood. In addition, immunoglobulin can prevent neutrophil storage pool depletion and maintain circulating blood neutrophils. Staphylococci are becoming an increasing problem in nosocomial infection and opsonic antibodies may play an important role in immunity to both coagulate negative and positive staphylococcal infections. As bacteria become resistant to antibiotics, antibodies may become a critical part of our antimicrobial armamentarium.
Configural representations in transverse patterning with a hippocampal model.

The hippocampus is necessary in both humans and rats for learning configural representations in tasks such as transverse patterning. The transverse patterning task, (A+B−,B+C−,C+A−), requires representing individual stimuli in the context of other stimuli. This paper extends a previous application to rat data [INNS World Congress on Neural Networks, 1995; Biol Cybern 6 (1998a) 203] by applying a model of the CA3 region of the hippocampus to human data. A decision function is also added that enables the system to choose among training items. Analysis of the simulations show that configural representations are formed by unique neural codes that depend on temporal and stimuli context. Based on the simulations, we hypothesize that configural representations in biological networks depend on a proper balance of input and context representations. Furthermore, the division of labor between functions in the model is a specific working hypothesis that in learning this task the hippocampus specializes in sequence prediction and the decision function evaluates the predictions.
Concept of a modified flywheel for megajoule storage and pulse conditioning

The concept of a flywheel with a variable moment of inertia for electromagnetic launch (EML) is introduced. The modified flywheel will further improve the energy density and efficiency. Coupled to a pulse-duty generator, it could produce a near-square pulse or other desirable pulse shapes. The amount of energy, its rate, and its switching all could be controlled prior to electric energy conversion. The modified flywheel is structured with masses movable along radial paths. Potential energy is stored with respect to mass position and kinematic energy with respect to spin. This mass positioning provides a means to control the rate of energy discharge. Control with spring-loaded weight would have near constant spin output. A servomechanism scheme can, however, provide the precise inward-moving positioning control of masses, and hence the other desirable output pulse conditioning. In the conventional flywheel, energy is always discharged in an exponential decay. In an EML system, a flywheel is the rotor of the pulse-duty generator, such as in the homopolar generator, compulsator, or the disk alternator. >
The Tabular Mode: Not Just Another Way to Represent a Function

Understanding mathematical functions as systematic processes involving the covariation of related variables is foundational in learning mathematics. In this article, findings are reported from two investigations examining students' thinking processes with functions. The first study focused on seven middle school students' explorations with a dynamic physical model. Students were videotaped during the 20- to 45-minute sessions occurring two or three times per week over a period of 2 months, and students' written work was collected. The second investigation included 19 preservice elementary and middle school teachers enrolled in a course focusing on a combination of mathematical content and pedagogy. Participants' written problem-solving work and reflective writing were collected, and participants were individually interviewed in 50-minute videotaped sessions. Results from both investigations indicated that students often relied on a table, or some variation of a table, as a cognitive link advancing the development of their reasoning about underlying function relationships.
Characterizing fracture energy of proton exchange membranes using a knife slit test

Pinhole formation in proton exchange membranes (PEM) may be caused by a process of flaw formation and crack propagation within membranes exposed to cyclic hygrothermal loading. Fracture mechanics can be used to characterize the propagation process, which is thought to occur in a slow, time-dependent manner under cyclic loading conditions, and believed to be associated with limited plasticity. The intrinsic fracture energy has been used to characterize the fracture resistance of polymeric material with limited viscoelastic and plastic dissipation, and has been found to be associated with long-term durability of polymeric materials. Insight into this limiting value of fracture energy may be useful in characterizing the durability of proton exchange membranes, including the formation of pinhole defects. In an effort to collect fracture data with limited plasticity, a knife slit test was adapted to measure fracture energies of PEMs, resulting in fracture energies that were two orders of magnitude smaller than those obtained with other fracture test methods. The presence of a sharp knife blade reduces crack tip plasticity, providing fracture energies that may be more representative of the intrinsic fracture energies of the thin membranes. Three commercial PEMs were tested to evaluate their fracture energies (Gc) at temperatures ranging from 40 to 90 °C and humidity levels varying from dry to 90% relative humidity (RH). Experiments were also conducted with membrane specimens immersed in water at various temperatures. The time temperature moisture superposition principle was applied to generate fracture energy master curves plotted as a function of reduced cutting rate based on the humidity and temperature conditions of the tests. The shift with respect to temperature and humidity suggests that the slitting process is viscoelastic in nature. Also such shifts were found to be consistent with those obtained from constitutive tests such as stress relaxation. The fracture energy is more sensitive to temperature than on humidity. The master curves converge at the lowest reduced cutting rates, suggesting similar intrinsic fracture energies; but diverge at higher reduced cutting rates to significantly different fracture energies. Although the relationship between Gc and ultimate mechanical durability has not been established, the test method may hold promise for investigating and comparing membrane resistance to failure in fuel cell environments. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 333–343, 2010
Analytical gradient of the CIS(D) perturbative correction to single‐excitation configuration interaction excited states

The complete spin–orbital formulation of the analytical first-derivative expression of the CIS(D) energy correction (doubles correction to the excitation energy from configuration interaction with single substitution, CIS) is presented. The CIS(D) method gives a perturbative correction to the CIS energy (which is roughly analogous to the Hartree–Fock energy for ground states) in a way that resembles second–order Moller–Plesset (MP2) theory for ground states. © 1995 John Wiley & Sons, Inc.
Synergies between Asphaltene Stabilizers and Demulsifying Agents Giving Improved Demulsification of Asphaltene-Stabilized Emulsions

Asphaltenes are known to stabilize water-in-oil emulsions, making it more difficult to demulsify and desalt crude oils. Insufficiently demulsified or desalted crude oil can lead to process upsets in the operation of desalters and separator vessels. Asphaltene stability and the methods used in predicting them have been correlated to the ease of demulsification. Two case studies are presented that show the effects of chemical demulsifiers used alone and in combination with asphaltene stabilizers on the efficiency of demulsification operations. The data shows that the asphaltene stabilizer−demulsifier combination does a better job at demulsifying crude oils with asphaltene-stabilized emulsions than when demulsifiers are used alone. While the data shows the action of the asphaltene stabilizer−demulsifier combination is crude specific, a careful choice of such combinations through initial testing can go a long way at solving troublesome asphaltene-stabilized emulsion problems in both refineries and oilfield pr...
Apheresis in treatment of the inflammatory demyelinating peripheral neuropathies.

: The inflammatory demyelinating peripheral neuropathies are recognizable treatable entities within the broad field of diseases of the peripheral nervous system. Most peripheral nerve diseases are still of undetermined causation and have no direct disease-modifying treatment. This paper reviews the diagnostic features of the inflammatory neuropathies, presumed mechanisms of pathogenesis, and the role of apheresis, along with other immunomodulating therapies, in the management of these diseases.
Dual rectangular jets from a flat plate in a crossflow

Wind tunnel tests were carried out in order to study the single and dual rectangular crossflow jets injected from a flat plate perpendicular to a free stream. The length-to-width ratio of the jets was 3.97, and the spacing between the center lines was 4.7 times the width of a single jet. Surface pressure distributions were obtained for jet-to-freestream velocity ratios of 2.2 and 4, respectively. The following conclusions are offered on the basis of the experimental results: (1) the downstream extension of the negative pressures is extended to the dual jets in comparison to the single jet; (2) by increasing the jet-to-freestream velocity ratio the downstream extension of negative pressures is reduced, but negative upstream pressures become larger; (3) very high peak negative pressures occur at the front side edges of the rectangular jets compared to round jets. Velocity vector plots in the flowfield of the dual jets are given.
Fire parameterization on a global scale

[1] We present a convenient physically based global-scale fire parameterization algorithm for global climate models. We indicate environmental conditions favorable for fire occurrence based on calculation of the vapor pressure deficit as a function of location and time. Two ignition models are used. One assumes ubiquitous ignition, the other incorporates natural and anthropogenic sources, as well as anthropogenic fire suppression. Evaluation of the method using Global Precipitation Climatology Project precipitation, National Centers for Environmental Prediction/National Center for Atmospheric Research temperature and relative humidity, and Moderate Resolution Imaging Spectroradiometer (MODIS) Leaf Area Index as a proxy for global vegetation density gives results in remarkable correspondence with global fire patterns observed from the MODIS and Visible and Infrared Scanner satellite instruments. The parameterized fires successfully reproduce the spatial distribution of global fires as well as the seasonal variability. The interannual variability of global fire activity derived from the 20-year advanced very high resolution radiometer record are well reproduced using Goddard Institute for Space Studies general circulation models climate simulations, as is the response to the climate changes following the eruptions of El Chichon and Mount Pinatubo. In conjunction with climate models and data sets on vegetation changes with time, the suggested fire parameterization offers the possibility to estimate relative variations of global fire activity for past and future climates.
Vibrational spectra and normal coordinate analysis of isotopically labeled formic acid monomers

Present address of Duane R, Kirklin: National Bureau of Standards, Washington, D. C., 20234. Ellis R, Lippincott: Posthumous.
A shift in the salt bridge interaction of residues D620 and E621 mediates the constitutive activation of Jak2-H538Q/K539L

Jak2 mutations in the exon 14 and exon 12 regions that cause constitutive activation have been associated with myeloproliferative neoplasms. We have previously shown that a pi stacking interaction between F617 and F595 is important for the constitutive activation of Jak2-V617F (Gnanasambandan et al., Biochemistry 49:9972–9984, 2010). Here, using a combination of molecular dynamics (MD) simulations and in vitro mutagenesis, we studied the molecular mechanism for the constitutive activation of the Jak2 exon 12 mutation, H538Q/K539L. The activation levels of Jak2-H538Q/K539L were found to be similar to that of Jak2-V617F, and Jak2-H538Q/K539L/V617F. Data from MD simulations indicated a shift in the salt bridge interactions of D620 and E621 with K539 in Jak2-WT to R541 in Jak2-H538Q/K539L. When compared to Jak2-WT, K539A mutation resulted in increased activation, while K539D or K539E mutations diminished Jak2 activation by 50 %. In the context of Jak2-H538Q/K539L, R541A mutation reduced its activation by 50 %, while R541D and R541E mutations returned its activation levels to that of Jak2-WT. Collectively, these results indicate that a shift in the salt bridge interaction of D620 and E621 with K539 in Jak2-WT to R541 in Jak2-H538Q/K539L is critical for constitutive activation of this Jak2 exon 12 mutant.
Instabilities in Gravity Driven Flow of Thin Fluid Films

This paper presents theoretical, computational, and experimental aspects of the instability development in the flow of thin fluid films. The theoretical part involves basic fluid me- chanics and presents derivation of the thin film equation using lubrication approximation. A simplified version of this equation is then analyzed analytically using linear stability analysis, and also numerically. The results are then compared directly to experiments. The experimental part outlines the setup, as well as data acquisition and analysis. This immediate comparison to experiments is very useful for gaining better insight into the interpretation of various theoretical and computational results.
Evidence of creative destruction in the U.S. economy

Schumpeter discusses the importance of innovation and new firm entry in a capitalistic economy as a means to “creatively destruct” oligopolies and generate new economic wealth. He warns of RD Schumpeter feared the obsolescence of entrepreneurship would result in an increasing concentration of wealth among large corporations and toward socialism.
VEGF internalization is not required for VEGFR-2 phosphorylation in bioengineered surfaces with covalently linked VEGF

Vascular endothelial growth factor (VEGF) is known to activate proliferation, migration, and survival pathways in endothelial cells through phosphorylation of VEGF receptor-2 (VEGFR-2). VEGF has been incorporated into biomaterials through encapsulation, electrostatic sequestration, and covalent attachment, but the effect of these immobilization strategies on VEGF signaling has not been thoroughly investigated. Further, although growth factor internalization along with the receptor generally occurs in a physiological setting, whether this internalization is needed for receptor phosphorylation is not entirely clear. Here we show that VEGF covalently bound through a modified heparin molecule elicits an extended response of pVEGFR-2 in human umbilical vein endothelial cells (HUVECs) and that the covalent linkage reduces internalization of the growth factor during receptor endocytosis. Optical tweezer measurements show that the rupture force required to disrupt the heparin-VEGF-VEGFR-2 interaction increases from 3-8 pN to 6-12 pN when a covalent bond is introduced between VEGF and heparin. Importantly, by covalently binding VEGF to a heparin substrate, the stability (half-life) of VEGF is extended over three-fold. Here, mathematical models support the biological conclusions, further suggesting that VEGF internalization is significantly reduced when covalently bound, and indicating that VEGF is available for repeated phosphorylation events.
Simulation of continuous system models in industrial engineering

Abstract Many industrial engineering and operations research studies in the creation of continuous dynamic models; that is, models consisting of a system of ordinary differential equations. Such models arise frequently in the analysis of economic, inventory and production control systems. The area of Industrial Dynamics (more recently named Systems Dynamics) is specially oriented toward modeling and simulation of these dynamic systems. The purpose of this paper is to discuss briefly some of the current techniques for modeling and simulation of continuous systems and then to devote major attention to describing a number of difficulties encountered in the actual digital simulation. Finally, a number of specific suggestions will be offered to prevent the occurence of most of these problems.
Increased ultrasound contrast and decreased microbubble destruction rates with triggered ultrasound imaging.

Although transient myocardial contrast imaging has been able to produce visually evident myocardial contrast in animals and humans with very low intravenous doses of perfluorocarbon-exposed sonicated dextrose albumin (PESDA) microbubbles, the mechanism for improved contrast remains unclear. In this study we devised a flow chamber that measured the concentration of PESDA microbubbles that remained after exposure to diagnostic ultrasound pressures of 0.9 to 1.9 MPa and frequencies of 2.0, 2.5, and 3.5 MHz (first and second harmonic for 2.0 MHz), which were delivered at either 30 Hz (frames per second), 0.5 to 1.0 Hz, or without any ultrasound transmission. The videointensity within the flow chamber was also measured at 0, 20, 40, and 100 ml/min flow rates with the flow loop closed (i.e., constant microbubble concentration) with both triggered (0.5 to 1.0 Hz) and conventional (30 Hz) frame rates. The effluent microbubble concentration was significantly larger when PESDA was exposed to either no ultrasound or 0.5 to 1.0 Hz ultrasound. Furthermore, the videointensity of a constant number of microbubbles was significantly greater with 0.5 to 1.0 Hz (triggered) compared with 30 Hz (conventional) frame rates at each transmit frequency. The greatest difference was noted with the lower 2.0 MHz transmit frequency and the 20 ml/min flow rate, especially when a second harmonic receiving frequency was used. We conclude that the mechanism for improved contrast with triggered ultrasound imaging is because of both less microbubble destruction and increased videointensity from a constant number of microbubbles. Lower transducer frequencies and lower flow rates result in the greatest improvement in videointensity with triggered ultrasound transmission.
A protein component of Drosophila polar granules is encoded by vasa and has extensive sequence similarity to ATP-dependent helicases

Abstract Determinants of pole cells, which are precursors of the germ line, are provided maternally and are localized to the posterior pole of the Drosophila egg, as are polar granules. It has been hypothesized that certain RNA molecules associated with polar granules may be necessary for pole cell determination. Using a monoclonal antibody (Mab46F11) against polar granules, we have cloned the gene for one of their components. This gene turns out to be vasa , which is required maternally for the formation of polar granules and germ cells. This polar granule component shows significant sequence similarity to elF-4A, a translation initiation factor that binds to mRNA, and to other helicases.
Ontogeny of Microvascular Permeability to Macromolecules in the Chick Chorioallantoic Membrane during Normal Angiogenesis

Abstract Chick embryos were incubated using standard shell-less techniques for microscopic observations at Days 4.5, 5.0, and 5.5 of the normal 21-day gestation. The chorioallantoic membrane (CAM) was prepared for intravital fluorescence confocal microscopy. A graded series of FITC-dextrans (20, 40, 70, and 150 kDa) was injected via vitelline vein. The changes in interstitial optical intensity due to FITC-dextran extravasation were evaluated by computer-assisted image analysis. Apparent permeability coefficients ( P s ) were calculated for first order postcapillary vessels from the changes in intensity as a function of time. On Day 4.5, P s values (means ± SE × 10 -7 cm/sec) in the CAM microvessels for FITC-Dextran 20, 40, 70, and 150 were 11.8 ± 1.0, 6.4 ± 0.4, 3.1 ± 0.5, and 1.5 ± 0.5, respectively. The respective P s values fell dramatically on Day 5.0 to 2.2 ± 0.5, 0.7 ± 0.2, 0.6 ± 0.2, and 0.6 ± 0.2. On Day 5.5, P s values for all these FITC-dextrans were equal to 0.7 ± 0.3. The evaluation of FITC-Dextran 10 on Day 5.5 yielded a P s value of 1.9 ± 0.3. Our data demonstrate a rapid reduction in microvascular permeability to macromolecules during normal angiogenesis in the early stages of CAM development. Our data also suggest that these changes in permeability may reflect functional adaptations of the CAM. A comparison of our data to those available in the literature for adult and tumoral tissues demonstrates that microvascular permeability properties in these tissues are different from those of the CAM.