bluuebunny/crossref_metadata_2025 huggingface dataset:
Teleconnections and low‐frequency variability in idealized experiments with two storm tracks
Authors: Franzke Christian , Fraedrich Klaus , Lunkeit Frank
Published: February 2007

Low‐frequency variability and teleconnection patterns induced by two storm tracks in idealized experiments depend on their zonal distance. A separation of about 150°, which resembles the northern hemisphere storm‐track distribution, reveals teleconnection patterns which are similar to the Pacific North American (PNA) pattern and the North Atlantic Oscillation (NAO). The NAO‐like structure is associated with retrograde travelling Rossby waves; barotropic stream‐function tendencies show that the interaction of the stationary eddies with the low‐frequency flow and the high‐frequency eddies contribute to the amplification of the pattern. Its decay is due to their interaction with the zonal‐mean flow, and the low‐frequency contribution to the divergence term. The PNA‐like pattern has a longer memory and is linked to a quasi‐stationary wave. The stationary‐wave activity flux shows the dominating influence of baroclinic processes and the other storm track further upstream. The correlation between the teleconnection indices is significant for storm‐track distances between 180° and 160°, and vanishes between 150° and 130°.
Blocking as a local instability to zonally varying flows
Authors: Swanson K. L.
Published: February 2007

An idealized system consisting of a steady‐state, axisymmetric vortex patch with topography forcing variations in the basic‐state flow along the vortex edge is shown to possess local instabilities for a broad range of parameters. One branch of these instabilities corresponds in scale and structure to observed atmospheric blocks. The nonlinear equilibration of these blocking‐type instabilities reproduces many aspects of observed blocking onsets; the potential for rapid non‐modal growth and ready excitation of these local instabilities by transients suggests that this instability may lie at the root of observed blocking onsets.
A scaling hypothesis for moist convective updraughts
Authors: Stiller Olaf , Craig George C.
Published: February 2007

The mixing of air between clouds and their environment is investigated with the help of a simplified model problem that contains only a small number of dynamically relevant parameters whose influence can be systematically explored. The classical model of a buoyant thermal, extensively studied in laboratory experiments, is generalized to include the key moist processes of condensation and re‐evaporation of cloud water. We consider the evolution of an isolated thermal initiated from a spherical warm and moist bubble at rest in a moist neutral sounding. The moist thermal loses buoyancy through mixing with the unsaturated environmental air, and finally collapses. The effect of moist physics on the thermal is shown to be represented by only three scale‐independent parameters. We present large‐eddy simulations that exhibit an approximate dynamical similarity, in that the loss of buoyancy resulting from the mixing process is mainly described by a single scale‐invariant parameter which we call the effective buoyancy, Beff. In order for the thermal to ascend a distance significantly larger than its initial diameter, Beff must be much greater than unity. This implies that the environment must be close to saturation if the bubble has an initial buoyancy that is typical of real clouds. It is also shown that the stratification of the environment induces a length scale, Lbuo, for a thermal with a given buoyancy excess. The resulting scale‐independent parameter Leff = L/Lbuo (where L is the initial bubble radius) is shown to affect the geometry of the thermal. Indeed, the thermal may break up if Leff is too large. These geometrical effects can be explained by relating Lbuo to the depth reached by forced downdraughts, which corresponds to the vertical extent of the largest eddies that entrain unsaturated air into the thermal.
Atmospheric absorption of near infrared and visible solar radiation by the hydrogen bonded water dimer
Authors: Vaida V. , Daniel J. S. , Kjaergaard H. G. , Goss L. M. , Tuck A. F.
Published: February 2007

Based on the physico‐chemical properties of water dimers, their near infrared and visible absorption of solar radiation in the earth's atmosphere is calculated. The calculation uses equilibrium constants determined by statistical mechanics, and a vibrational absorption spectrum determined by a coupled oscillator quantum mechanics model and ab initio quantum chemistry. The resulting total atmospheric absorption was calculated using a line‐by‐line radiative‐transfer model, and depends significantly on the dimer abundance, as well as on the frequency and line width given to vibrational transitions. The best estimate achieved for the possible range of total absorption from 400 nm to 5000 nm by water dimer in the tropics is 1.6–3.3 W m−2. In a global‐warming scenario, the increased temperature and water vapour partial pressure result in a nonlinear increase in the absorption of solar radiation by water clusters. Most of the energy from water dimer absorption is deposited in the lower troposphere, particularly in the tropics, tending to make it more convective.
Multi‐year simulations using a regional‐climate model over the Iberian Peninsula: Current climate and doubled CO2scenario
Authors: Gallardo Clemente , Arribas Alberto , Prego Juan A. , Gaertner Miguel A. , De Castro Manuel
Published: February 2007

In order to analyse the regional climate sensitivity in the Iberian Peninsula and surrounding areas to the global change related to an increase of CO2, two simulations (current climate and scenario) are performed using a regional‐climate model (RCM) one‐way nested in a global circulation model (GCM). Both simulations cover a ten‐year period. The results of the control simulation (current climate) are compared to a climatological database. RCM and GCM representations of the climate are realistic, but the RCM shows more detailed results. Following this, a statistical analysis of the differences between current climate and double CO2scenario simulations is carried out considering both 2 m temperature and precipitation. The analysis shows a significant warming in seasonal averages and important differences in the 2 m temperature interannual variability. Especially important is the strong increase in interannual variability of precipitation found in winter and autumn. Relationships between anomalies of general circulation (500 hPa geopotential field) and surface temperature, precipitation and cloudiness are also analysed, showing an important effect of cloud cover anomalies over the 2 m temperature interannual variability.
Ocean‐atmosphere‐land feedbacks in an idealized monsoon
Authors: Chou C. , Neelin J. D. , Su H.
Published: February 2007

An intermediate‐complexity atmospheric model coupled with a simple land‐surface model and a mixed‐layer ocean model is used to investigate the processes involved in an idealized monsoon occurring on a single rectangular continent. Idealized divergences of ocean heat transports are specified as an annual average ‘Q‐flux’. In this simple coupled configuration, the mechanisms that affect land‐ocean contrast and, in turn, the seasonal movement of the continental convergence zones are examined. These include soil‐moisture feedbacks: cooling of tropical oceans by ocean transpoit; ventilation, defined as the import into continental regions of low moist static‐energy air from ocean regions where heat storage opposes summer warming; and the ‘interactive Rodwell‐Hoskins mechanism’, in which Rossby‐wave‐induced subsidence to the west of monsoon heating interacts with the convection zone. The fixed ocean transports have a substantial impact on the continental convection. If Q‐flux is set to zero, subtropical subsidence and ventilation tend to substantially limit the poleward movement of summer monsoon rainfall. When land hydrology feedbacks are active, the drying of subtropical continents disfavours continental convection even in the tropics. When ocean transports are included, tropical oceans are slightly disfavoured as regions for producing convection which, by contrast, favours continental convection. The monsoon circulation then produces moisture transport from the ocean regions that allows substantial progression of convection into the subtropics over the eastern portion of the continent. The western portion of the continent tends to have a dry region of characteristic shape. This east‐west asymmetry is partly due to the interactive Rodwell‐Hoskins mechanism. The ventilation is of at least equal importance in producing east‐west asymmetry and is the single most important process in limiting the poleward extent of the continental convection zone.
The energetics of an upper tropospheric cyclonic vortex over north‐east Brazil
Authors: Mishra S. K. , Rao V. B.
Published: February 2007

The daily budget of zonal and eddy components of kinetic and available potential energy (APE) including boundary and generation terms are computed for a limited area from 52.5 to 22.5°W and from 20°S to 2.5°N and extending in the vertical from 1000 to 50 hPa, during the period 1–10 January 1993. During the vortex period, 5–10 January, a cyclonic vortex in the upper troposphere with its mean centre at 10°S, 35°W was present. The combined boundary pressure work and dissipation terms of the kinetic energy budget equations, as well as APE generation terms, are computed as residuals. The meridional transports of eddy momentum and sensible heat are also computed.

The time‐pressure distributions of the zonal and eddy components of kinetic energy (KZ and KE, respectively) and APE are examined. The upper layer 500–100 hPa is identified as the vertical layer which contains the vortex and its interaction with the ambient flow. A sharp increase of KZ in the upper layer is seen as an important feature of the pre‐vortex period 1–4 January. The role of boundary pressure work in the sharp increase of KZ associated with the development of a strong shear zone before the formation of the vortex is discussed. The vortex formation in the upper layer is associated with a rapid decrease of KZ, a sharp increase of KE and barotropic energy conversion from KZ to KE, the commencement of eddy APE (AE) to KE conversion and the generation of AE. These are identified as the main characteristics of the vortex formation from the time variation of energy variables. The vortex formation is also associated with a large increase of down‐the‐gradient eddy momentum transport.

It is found from the vertically integrated mean energy cycle in the upper layer that both the barotropic and AE to KE energy conversions maintain the vortex. However, the former is found to be 0.63 W m−2 and dominates over the latter by a factor of 3.5. A balance between the baroclinic energy conversion and the generation of AE is noted. The system is dynamically (thermally) more active in the vertical layer 350–100 hPa (500–100 hPa) as revealed by the vertical variation of energy variables. The reasonableness of computed energy variables is discussed qualitatively and quantitatively wherever possible.
Introduction: The scope of possibility in interpreting and promoting research‐based teaching
Authors: Kreber Carolin
Published: January 2007

Research‐based teaching is becoming increasingly important as the mandate of higher education institutions is being broadened.
The value of pedagogic inquiry for improving teaching
Authors: Gosling David
Published: January 2007

This chapter considers whether there are grounds for believing that an inquiry‐based approach to teaching and educational development will enhance practice.
Kinetics of glycine oxidation by N‐bromophthalimide in the presence of sodium dodecyl sulfate
Authors: Joshi Ghanat K. , Katre Y. R. , Singh Ajaya K.
Published: February 2007

The kinetics of oxidation of glycine by N‐bromophthalimide (NBP) were studied in the presence of an anionic surfactant, sodium dodecyl sulfate, in acidic medium at 308 K. The rate of reaction was found to have first‐order dependence on [NBP] and fractional‐order dependence on [glycine] and [H+]. The addition of reduced product of the oxidant had no significant effect on the rate of reaction. Increasing [Hg(OAc)2] and [Br−] increased the rate of reaction, whereas a change in ionic strength (μ) of the medium had no effect on oxidation velocity. The rate of reaction decreased with a decrease in dielectric constant of the medium. HCN was identified as the main oxidation product of the reactions. The various activation parameters have been computed. A suitable mechanism consistent with the experimental findings has been proposed. The index of cooperativity and the micelle binding constant have been calculated.
Novel surfactants for ultralow interfacial tension in a wide range of surfactant concentration and temperature
Authors: Aoudia Mohamed , Al‐Shibli Mohamed Nasser , Al‐Kasimi Liali Hamed , Al‐Maamari Rashid , Al‐bemani Ali
Published: February 2007

This work investigates the possibility of injecting dilute aqueous solutions of novel surfactants into the Yibal field (Sultanate of Oman). This was accomplished through an experimental protocol based on the following criteria: (i) compatibility of the surfactants with the high‐saline reservoir water (∼200 g/L); (ii) low interfacial tension (IFT) between crude oil and reservoir water (less than 10−2 mN m−1); and (iii) maintaining the low IFT behaviour during the entire surfactant flooding. Novel surfactants selected in this study consist of a series of ether sulfonates (AES‐205, AES‐128, AES‐506, and 7–58) and an amphoteric surfactant (6–105). These surfactants were found to be compatible with reservoir water up to 0.1% surfactant concentration, whereas 6–105 and 7–58 showed compatibility within the full range of surfactant concentration investigated (0.001–0.5%). All surfactant systems displayed dynamic IFT behavior, in which ultralow transient minima were observed in the range 10−4–10−3 mN m−1, followed by an increase in the IFT to equilibrium values in the range 10−3–10−1 mN m−1. The results also showed that with respect to concentration (0.05–0.5%) and temperature (45–80°C), AES‐205 and 7–58 surfactants exhibit a wide range of applicability, with the IFT remaining below 10−2 mN m−1, as required for substantial residual oil recovery. In addition, ultralow IFT were obtained at surfactant concentrations as low as 0.001%, making the use of these surfactants in enhanced oil recovery extremely cost‐effective.
Impact of 20∶4n−6 supplementation on the fatty acid composition and hemocyte parameters of the pacific oyster crassostrea gigas
Authors: Delaporte Maryse , Soudant Philippe , Moal Jeanne , Giudicelli Emilie , Lambert Christophe , Séguineau Catherine , Samain Jean‐François
Published: February 2007

Arachidonic acid (20∶4n−6, ArA) and its eicosanoid metabolites have been demonstrated to be implicated in immune functions of vertebrates, fish, and insects. Thus, the aim of this study was to assess the impact of ArA supplementation on the FA composition and hemocyte parameters of oysters Crassostrea gigas. Oyster dietary conditioning consisted of direct addition of ArA solutions at a dose of 0, 0.25, or 0.41 μg ArA per mL of seawater into tanks in the presence or absence of T‐Iso algae. Results showed significant incorporation of ArA into gill polar lipids when administered with algae (up to 19.7%) or without algae (up to 12.1%). ArA supplementation led to an increase in hemocyte numbers, phagocytosis, and production of reactive oxygen species by hemocytes from ArA‐supplemented oysters. Moreover, the inhibitory effect of Vibrio aestuarianus extracellular products on the adhesive proprieties of hemocytes was lessened in oysters fed ArA‐supplemented T‐Iso. All changes in oyster hemocyte parameters reported in the present study suggest that ArA and/or eicosanoid metabolites affect oyster hemocyte functions.
Accelerated solvent extraction for quantitative measurement of fatty acids in plasma and erythrocytes
Authors: Kuriki Kiyonori , Tajima Kazuo , Tokudome Shinkan
Published: February 2007

Consumption of fish rich in n‐3 highly unsaturated FAs (i.e., EPA and DHA) has been suggested to decrease the risk of lifestyle‐related diseases such as coronary heart disease, cancer, diabetes, and dementia. Blood eevels of those FA are known appropriate biomarkers of both the corresponding dietary FA intakes and fish consumption. In place of traditional handwork methods for extracting FA, we performed an accelerated solvent extraction (ASE) for at least 13 selected FA in plasma and erythrocytes to measure them by GLC. The FA levels (concentrations and compositions) in 35–50 μL of plasma or erythrocytes were extracted by ASE and measured by GLC. Intra‐and interassay coefficients of variation were≤6.0% for both blood materials, except with a minor group of FA (≤1.0% of total FA). When ASE was compared with two traditional handwork methods, FA levels in plasma from 18 healthy subjects were all coincident with very high Pearson's correlation coefficients for the three sets of the sama 18 samples (r≤0.85 to 0.95, P<0.0001), except for 18∶0 (r=0.59, P<0.01). Using ASE and GLC, we have developed a new method for determination the levels of FA in plasma and erythrocytes as biomarkers for dietary intake of fish, fat, and FA. This new method makes it feasible to measure small volumes of samples, automatically, quantitatively, routinely, easily, rapidly and cheaply, with acceptable precision and accuracy.
CHAPTER 9 Delivering HPV vaccine in the industrial and developing world: the role of the ob‐gyn community
Authors: Kane Mark A.
Published: February 2007

The development and demonstration of the safety and effectiveness of new HPV vaccines is a major breakthrough in medical science that could prevent most cases of cervical cancer, the first or second cause of cancer death in women in most developing countries. This chapter discusses the delivery of HPV vaccine in the industrial and developing world, from the point of view of what obstetricians and gynecologists need to know to use and advocate for the use of this powerful new tool.
CHAPTER 11 How to manage and communicate with patients about HPV?
Authors: Garland Suzanne M. , Quinn Michael A.
Published: February 2007

The whole concept of abnormal Pap smears and cervical cancer being due to an STI poses enormous challenges to the healthcare provider. The psychological and psychosocial sequelae of misinformation are potentially damaging both to the woman and her partner. There is a clear responsibility for the information around this to be simple, relevant, reassuring and comprehensible. Written information is invaluable.
A COMPARISON OF ALGEBRAS OF FUNCTIONS OF BOUNDED VARIATION
Authors: Ashton Brenden , Doust Ian
Published: January 2007

Motivated by problems in the spectral theory of linear operators, we previously introduced a new concept of variation for functions defined on a non-empty compact subset of the plane. In this paper, we examine the algebras of functions of bounded variation one obtains from these new definitions for the case where the underlying compact set is either a rectangle or the unit circle, and compare these algebras with those previously used by Berkson and Gillespie in their theories of AC-operators and trigonometrically well-bounded operators.
Lymphangioma of the larynx
Authors: Vaishali B , Nambiar A , Indudharan R
Published: January 2007

Lymphangiomas are uncommon congenital lesions of the lymphatic system. Most of these lesions present in infancy or early childhood with a swelling in the head and neck region. We report a case of adult lymphangioma of the larynx. We also discuss the presentation, diagnosis and management of this tumour, and we present the current debate on sclerotherapy versus surgery for these tumours.
Response from David Bentley Hart to McGuckin and Murphy
Authors: Hart David Bentley
Published: January 2007

I should first of all thank John McGuckin and Francesca Murphy for their remarks; both are scholars I very much respect, and it is flattering that they think my work worthy of their scrutiny and of – occasionally – their animadversions. I much prefer praise to censure, of course, but only the latter affords any scope for a meaningful reply. One dare not respond to a compliment by agreeing with it, or amplifying upon it; but to demur from it is to squander a gift that may not come again. So it is probably for the best that, even if I have apparently succeeded on the whole in pleasing both readers, I have nevertheless failed to please either of them in every particular. And I hope I may be excused for confining my replies almost entirely to their more critical remarks.
Optimization of Protein Fusion Partner Length for Maximizing in Vitro Translation of Peptides
Authors: Loose Christopher R. , Langer Robert S. , Stephanopoulos Gregory N.
Published: February 2007

Using protein fusion partners for in vitro translation may increase solubility, assist in purification, or allow detection of small proteins and peptides. Here we show that the molar yield of peptide in a batch reaction may be maximized by optimizing the length of the translated product, which is composed of the fusion partner plus the peptide. Using truncated versions of GFP as a series of fusion partners, the molar yield increased approximately 3‐fold as the length of the translated product was reduced from 250 to 100 amino acids. When the translated product was shortened below roughly 100 amino acids, molar yield fell as a result of proteolysis. This trend was verified using two fusion partners with different amino acid sequences. Furthermore, protease inhibitors were used to confirm that proteases were responsible for limiting accumulation of peptides below the optimal length.
Tumorvorsorge und Tumorfrüherkennung - Sinn und Unsinn
Authors: Eckert
Published: February 2007

Trotz der grossen Bedeutung von Tumorkrankheiten ist die Zahl der Massnahmen mit gesichertem Nutzen zur Vorsorge und Früherkennung limitiert. Von den Verhaltensempfehlungen zur Krebsprävention, wie sie im European Cancer Code formuliert sind, kommt insbesondere dem Verzicht auf Rauchen, einer «gesunden» Ernährung sowie dem Vermeiden von Übergewicht grosse Bedeutung zu. Bezüglich spezifischer Screeninguntersuchungen für die häufigsten Krebserkrankungen liegt Evidenz für Morbiditäts- und Mortalitätsreduktion für Programme der Darmkrebs-, Brustkrebs- und Zervixkarzinomfrüherkennung vor, sie fehlt aber – zumindest derzeit noch – für Tumorerkrankungen von Prostata und Lunge.
Künstlerische Therapien: Zusammenstellungen von Studien zu Künstlerischen Therapien in der Onkologie und Geriatrie
Authors: Kunzmann Bettina , Aldridge David , Gruber Harald , Wichelhaus Barbara
Published: February 2007

Zusammenfassung. Im Rahmen der Einführung des DRG-Fallpauschalensystems (diagnosis related groups) wurde zur Begründung der Aufnahme der Künstlerischen Therapien in das Klassifikationssystem der Prozeduren des OPS-301 (Operationsschlüssel) wissenschaftliche Belege eingefordert. Die Grundlage dafür wurden sowohl durch die “Zusammenstellungen von Studien in der Akutmedizin und Onkologie“ zur Begründung der psychosozialen Diagnostik und Therapie Künstlerischer Therapien erbracht, als auch durch die Beschreibung der Relevanz (d.h. fachlich unverzichtbar; fachlich etabliert; wissenschaftlich evaluiert; Angaben zum Evidenzgrad zitierter Studien; Angaben zu anderen internationalen Prozedurenklassifikationen) erfüllt. Die “Zusammenstellung von Studien in der Akutmedizin und Geriatrie“ aus 2004 entstand zur Begründung der Erweiterung der “geriatrischen frührehabilitativen Komplexbehandlung“ um Künstlerische Therapien (Kunsttherapie, Musiktherapie u.a.). Darin werden Aussagen über Künstlerische Therapien bezüglich Grundlagen, Methoden, Forschungen, Tätigkeitsfelder, Psychoonkologie, Geriatrie, Demenz sowie Abbildung in nationalen und internationalen Leitlinien gemacht. Weiterhin werden parlamentarische Anfragen, Stellungnahmen von Fachgesellschaften und Veröffentlichungen von Ministerien genannt. Künstlerische Therapien sind danach wichtige, etablierte und unverzichtbare Behandlungsansätze in klinischen Fachbereichen und gehören zur “good medical practice“. Der jetzt eingeschlagene Diskurs kann in Zukunft nur durch eine Vernetzung und Unterstützung bei der Recherche nach Studien fortgeführt werden. Auch im Blick auf die Integrierung in medizinische Behandlungsleitlinien ist der eingeschlagene Weg der qualitativen und quantitativen Forschung nur mit vereinten Kräften zu beschreiten.
Gesetzlicher Rahmen des Fallpauschalengesetzes - Qualitätssicherung und Erfassung psychosozialer Leistungen
Authors: Kunzmann Bettina , Aldridge David , Gruber Harald , Hamberger Christian , Wichelhaus Barbara
Published: February 2007

Zusammenfassung. Der gesetzliche Rahmen des Fallpauschalengesetzes beschreibt die Anwendung und Pflege der Diagnosis Related Groups (DRGs) über amtliche Klassifikationen von Diagnosen und Prozeduren. Sowohl eine Qualitätssicherung als auch eine Leistungserfassung der psychosozialen Therapien ist notwendig, da künstlerische Therapien in diesem System innerhalb der psychosozialen Therapien angesiedelt sind. Psychosoziale Mitarbeiter, also auch künstlerische TherapeutInnen, müssen ihre Leistungen erfassen durch Kodierung und Dokumentation. Zur Umsetzung gibt es Empfehlungen von Fachgesellschaften. Diese sind seit 2001 tätig geworden zur Sicherung der Psychosozialen und Künstlerischen Therapien in der Akutmedizin.
Fracture energy applicable to dry snow slab avalanche release
Authors: McClung D. M.
Published: January 2007

Dry slab avalanches release by a sequence of propagating fractures: first by shear fracture (mode II and mode III) in a weak layer at the base of the slab and second by tensile fracture through the crown after which release of the slab is imminent. The fracture energy is the energy which must be provided to produce a unit area of fracture surface. It is a key parameter in determining how and when fractures will propagate and important slab characteristics such as length and width that are necessary in order to estimate slab mass and volume in relation to destructive potential. In this paper, approximate estimates of fracture energy are calculated from field measurements of slab properties, laboratory measurements and in‐situ strength tests in alpine snow. Estimates of fracture energy are given for both tensile fracture (mode I) through the crown as well as for shear fracture (mode II) in fragile weak layers of slab avalanches. The results, when compared with other values from ice, rock and engineering materials, suggest that snow has the lowest values.
First observation of H15NO3 in atmospheric spectra
Authors: Brizzi G. , Carlotti M. , Flaud J.‐M. , Perrin A. , Ridolfi M.
Published: February 2007

Using new and accurate experimental results concerning the spectroscopic properties of the H14NO3 and H15NO3 molecules, as well as improved theoretical methods, it has been possible to generate an improved set of line parameters for these molecules in the 11.2 μm spectral region. These line parameters were used to detect for the first time the H15NO3 molecule in the atmosphere analyzing atmospheric spectra recorded by the MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) experiment. The evidence of H15NO3 in the atmosphere was achieved exploiting the features of the Residual and Error Correlation analysis.
Protein tyrosine phosphatase function: the substrate perspective
Authors: Tiganis Tony , Bennett Anton M.
Published: January 2007

It is now well established that the members of the PTP (protein tyrosine phosphatase) superfamily play critical roles in fundamental biological processes. Although there has been much progress in defining the function of PTPs, the task of identifying substrates for these enzymes still presents a challenge. Many PTPs have yet to have their physiological substrates identified. The focus of this review will be on the current state of knowledge of PTP substrates and the approaches used to identify them. We propose experimental criteria that should be satisfied in order to rigorously assign PTP substrates as bona fide. Finally, the progress that has been made in defining the biological roles of PTPs through the identification of their substrates will be discussed.
Administration of brain natriuretic peptide improves cardiac function following operations using extracorporeal circulation in an animal model
Authors: Bail Dorothee H. L. , Steger Volker , Heinzelmann Uli , Schiller Sandra , Geim Anita I. , Brüllmann Benjamin , Ziemer Gerhard
Published: February 2007

The critical phase during cardiosurgical procedures is weaning the diseased heart from the ECC (extracorporeal circulation). Post-ischaemic heart failure sometimes requires the administration of inotropic and/or vasconstrictive agents. The natriuretic peptides influence pre- and after-load through their natriuretic, diuretic and vasodilating actions. To date, there are only a few reports describing the therapeutic effect of BNP (brain natriuretic peptide) administration during cardiosurgical procedures. The aim of the present study was to evaluate the effect of BNP administration following ECC in an animal model. Surgery was performed on 20 pigs using ECC. A 30-min ischaemic episode was simulated. Following de-clamping, BNP was administered to the BNP group (n=10) by an i.v. (intravenous) bolus at 0.3 μg·kg−1 of body weight·min−1, followed by an infusion at a rate of 0.015 μg·kg−1 of body weight·min−1 for 60 min. The animals in the control group (n=10) received a saline solution instead of BNP. Haemodynamic and clinical chemistry parameters as well as the amount of catecholamines that were required were measured. All of the animals in the BNP group had a significantly better cardiac output and cardiac index at the end of the experiment. Seven out of 10 animals from the control group required catecholamines, whereas only one animal from the BNP group did. Creatine kinase levels were significantly lower in the BNP group. Systemic vascular resistance was markedly lower in the BNP group. In conclusion, administration of BNP is highly effective in treating post-ischaemic heart failure following ECC. Haemodynamics are greatly improved, and there is almost no need for pharmacological support.
Plasma concentration of Fas/Fas ligand and left ventricular function in response to metoprolol in conjunction with standard treatment
Authors: Hou Yuan-ping , Wu Jin-ling , Fan Qian , Liu Miao-bing , Yin Bao-ling , Zhang Lin
Published: February 2007

Recent studies suggest that cardiac myocyte apoptosis contributes to the progress of CHF (congestive heart failure). In the present study, we tested the hypothesis that metoprolol in conjunction with the standard treatment regime for CHF [an ACE (angiotensin-converting enzyme) inhibitor, diuretics and digoxin] may significantly reduce the plasma concentrations of the apoptotic mediators sFas (soluble Fas) and sFasL (soluble Fas ligand) in patients with CHF. An ELISA was used to determine the plasma concentrations of sFas and sFasL in 106 patients with stable CHF at recruitment. Echocardiography was performed at baseline and after 1 year of treatment with metoprolol in conjunction with the standard treatment regime for CHF (i.e. an ACE inhibitor, diuretics and digoxin). The dose of metoprolol was doubled on a biweekly basis up to 50 mg twice a day or maintained at the maximum tolerated dose. Data after 1 year were available for 92 patients and were analysed. The plasma concentrations of sFas and sFasL in patients with CHF decreased significantly (P<0.01) after 1 year of treatment with metoprolol in conjunction with the standard treatment regime compared with at baseline (5.4±0.2 compared with 3.2±0.1 ng/ml respectively for sFas, and 52.1±2.3 compared with 26.7±1.0 pg/ml respectively for sFasL). Compared with baseline, after 1 year of treatment with metoprolol in conjunction with the standard treatment regime there were significant improvements in LV (left ventricular) ejection fraction (from 32.6±0.9 to 51.5±0.8%; P<0.01), LV end-diastolic dimension (from 69.8±0.6 to 57.7±0.3 mm; P<0.01), LV end-systolic dimension (from 53.9±0.6 to 40.5±0.5 mm; P<0.01), LV end-diastolic volume (from 254.7±5.0 to 164.1±2.2 ml; P<0.01) and LV end-systolic volume (from 142.0±4.2 to 72.2±2.0 ml; P<0.01). In addition, the distance walked in a 6-min walk test increased markedly (P<0.01) from 260.3±5.2 m at baseline to 440.9±5.7 m after 1 year of treatment. In conclusion, we have demonstrated that metoprolol in conjunction with an ACE inhibitor, diuretics and digoxin in patients with CHF can lead to a reverse in LV remodelling potentially through its anti-apoptotic effects.
‘Is Marketed’ – The Story and the ECJ Decision. The Case of Generics [UK]
Authors: Rosenberg Howard
Published: February 2007

This paper looks at the history, consequences and current situation with respect to marketing a generic omeprazole product in the EU. In 1997, Astra (now AstraZeneca) took the disruptive strategy of limiting or avoiding generics competition, by withdrawing their capsule reference product and replacing it with a tablet product prior to generics registration being approved.
Intellectual Property and Access to Essential Medicines: Options for Developing Countries
Authors: Kuanpoth Jakkrit
Published: February 2007

This paper, which is an excerpt from the report on ‘Affordable ARV Drugs for People Living with HIV/AIDS in Vietnam: Legal and Trade Issues’ commissioned by the Ford Foundation, reviews some major issues relating to intellectual property and pharmaceuticals in order to find ways to increase or improve access to essential medicines for developing countries. It is suggested that developing countries should take positive steps to review and amend the existing law and policy relating to patents and pharmaceuticals. The following proposals may be adopted: prohibit patenting of the use, composition and combination of known medicines; encourage local production and import of generic drugs; encourage parallel import of patented medicines; review existing law to facilitate easy use of compulsory licensing; undertake price negotiation with the companies that hold patents; provide waiving of drug registration or provide a fast-track registration for generic medicines; and prohibit exclusive protection of test and other relevant data.
The emergence of chaos in a laser irradiated spherical absorber
Authors: Faraggi Eshel , Gerstman Bernard S. , Sun Jinming
Published: January 2007

We show in this paper that the simple system of a spherical absorber immersed in water can exhibit complex and chaotic behavior upon absorption of laser energy. We report on computer experiments performed on this simple system. We present power spectra and calculate Lyapunov exponents that show that for increasing laser pulse durations and increasing laser energy the pressure response of the system changes from periodic to a regime displaying spatiotemporal chaos. This is important from a theoretical point of view because the complex behavior displayed in this simple system makes it an excellent choice for investigations into the nonlinear dynamics of fluids and the complicated transition to turbulence. This is also important for people using these systems for various applications in material science and biomedicine.
Coupled dipole method to compute optical torque: Application to a micropropeller
Authors: Chaumet Patrick C. , Billaudeau C.
Published: February 2007

The coupled dipole method is a volume integral equation method which allows computation of the scattered field from an arbitrary object (shape and relative permittivity). This method has been extended to the computation of optical forces. In this article we further extend the coupled dipole method to the computation of optical torque. First, we establish the equation to obtain the optical torque using the coupled dipole method, stressing the importance of the radiative reaction term. Second, we compare our theory to existing models for validation. Third, we apply our method to the computation of optical torque, from a plane wave circularly polarized on a micropropeller. The influence of geometry and relative permittivity on the optical torque is studied.
Structural analysis of strained p-type AlGaN∕GaN superlattice
Authors: Tsai H. L. , Wang T. Y. , Yang J. R. , Chuo C. C. , Hsu J. T. , Čeh M. , Shiojiri M.
Published: January 2007

We investigated the nanostructure of AlGaN∕GaN strained-layer superlattice (SLS) cladding in the GaN-based violet laser diode (LD) and the AlInGaN-based ultraviolet (UV) light emitting diode (LED) with a scanning transmission electron microscope (STEM). In the p-SLS cladding, comprising 34 pairs of p-Al0.1Ga0.9N∕p-GaN:Mg layers in the GaN-based LD, the Al0.1Ga0.9N and GaN layers were distinguished as dark and bright bands ∼6nm wide in the high-angle annular dark-field (HAADF) STEM images. Threading dislocations (TDs) were observed. Among TDs that came from the underlying layer, some run outside through the SLS, and the others disappeared within the SLS, which discloses a role of the SLS in suppressing defect propagation. A HAADF-STEM image of the TD with a dark line along the center of a bright contour was found. The dark line, which was darker than the surrounding matrix, is striking. One of the probable explanations for the dark line that may be considered is local segregation of light atoms (Mg or Al) in Cottrell atmosphere around the dislocation core. In the HAADF-STEM image of the UV LED wafer, the AlInGaN and AlInGaN:Si layers in the MQW were definitely resolved, appearing as dark and bright bands. HAADF-STEM also distinguished between the AlGaN and GaN layers in the p-SLS cladding in the UV LED wafer.
Automated sample exchange and tracking system for neutron research at cryogenic temperatures
Authors: Rix J. E. , Weber J. K. R. , Santodonato L. J. , Hill B. , Walker L. M. , McPherson R. , Wenzel J. , Hammons S. E. , Hodges J. , Rennich M. , Volin K. J.
Published: February 2007

An automated system for sample exchange and tracking in a cryogenic environment and under remote computer control was developed. Up to 24 sample “cans” per cycle can be inserted and retrieved in a programed sequence. A video camera acquires a unique identification marked on the sample can to provide a record of the sequence. All operations are coordinated via a LABVIEW™ program that can be operated locally or over a network. The samples are contained in vanadium cans of 6–10mm in diameter and equipped with a hermetically sealed lid that interfaces with the sample handler. The system uses a closed-cycle refrigerator (CCR) for cooling. The sample was delivered to a precooling location that was at a temperature of ∼25K, after several minutes, it was moved onto a “landing pad” at ∼10K that locates the sample in the probe beam. After the sample was released onto the landing pad, the sample handler was retracted. Reading the sample identification and the exchange operation takes approximately 2min. The time to cool the sample from ambient temperature to ∼10K was approximately 7min including precooling time. The cooling time increases to approximately 12min if precooling is not used. Small differences in cooling rate were observed between sample materials and for different sample can sizes. Filling the sample well and the sample can with low pressure helium is essential to provide heat transfer and to achieve useful cooling rates. A resistive heating coil can be used to offset the refrigeration so that temperatures up to ∼350K can be accessed and controlled using a proportional-integral-derivative control loop. The time for the landing pad to cool to ∼10K after it has been heated to ∼240K was approximately 20min.
Hydrodynamic interaction in polymer solutions simulated with dissipative particle dynamics
Authors: Jiang Wenhua , Huang Jianhua , Wang Yongmei , Laradji Mohamed
Published: January 2007

The authors analyzed extensively the dynamics of polymer chains in solutions simulated with dissipative particle dynamics (DPD), with a special focus on the potential influence of a low Schmidt number of a typical DPD fluid on the simulated polymer dynamics. It has been argued that a low Schmidt number in a DPD fluid can lead to underdevelopment of the hydrodynamic interaction in polymer solutions. The authors’ analyses reveal that equilibrium polymer dynamics in dilute solution, under typical DPD simulation conditions, obey the Zimm [J. Chem. Phys. 24, 269 (1956)] model very well. With a further reduction in the Schmidt number, a deviation from the Zimm model to the Rouse model is observed. This implies that the hydrodynamic interaction between monomers is reasonably developed under typical conditions of a DPD simulation. Only when the Schmidt number is further reduced, the hydrodynamic interaction within the chains becomes underdeveloped. The screening of the hydrodynamic interaction and the excluded volume interaction as the polymer volume fraction is increased are well reproduced by the DPD simulations. The use of soft interaction between polymer beads and a low Schmidt number do not produce noticeable problems for the simulated dynamics at high concentrations, except for the entanglement effect which is not captured in the simulations.
Theory of C2Hx species on Pt{110} (1×2): Reaction pathways for dehydrogenation
Authors: Anghel A. T. , Wales D. J. , Jenkins S. J. , King D. A.
Published: February 2007

A complete reaction sequence for molecular dissociation at a surface has been characterized using density functional theory. The barriers for sequential ethane dehydrogenation on Pt{110} are found to fall into distinct energy sets: very low barriers, with values in the range of 0.29–0.42eV, for the initial ethane dissociation to ethene and ethylidene at the surface; medium barriers, in the range of 0.72–1.10eV, for dehydrogenation of C2H4 fragments to vinylidene and ethyne; and high barriers, requiring more than 1.45eV, for further dehydrogenation. For dissociation processes where more than one pathway has been found, the lowest energetic route links the most stable reactant adsorbed state at the surface to a product state involving the hydrocarbon moiety adsorbed in its most stable configuration at the surface. Hence there is a clear link between surface stability and kinetics for these species.
A new NMR method for determining the particle thickness in nanocomposites, using T2,H-selective X{H1} recoupling
Authors: Schmidt-Rohr K. , Rawal A. , Fang X.-W.
Published: February 2007

A new nuclear magnetic resonance approach for characterizing the thickness of phosphate, silicate, carbonate, and other nanoparticles in organic-inorganic nanocomposites is presented. The particle thickness is probed using the strongly distant-dependent dipolar couplings between the abundant protons in the organic phase and X nuclei (P31, Si29, C13, Al27, Na23, etc.) in the inorganic phase. This approach requires pulse sequences with heteronuclear dephasing only by the polymer or surface protons that experience strong homonuclear interactions, but not by dispersed OH or water protons in the inorganic phase, which have long transverse relaxation times T2,H. This goal is achieved by heteronuclear recoupling with dephasing by strong homonuclear interactions of protons (HARDSHIP). The pulse sequence alternates heteronuclear recoupling for ∼0.15ms with periods of homonuclear dipolar dephasing that are flanked by canceling 90° pulses. The heteronuclear evolution of the long-T2,H protons is refocused within two recoupling periods, so that H1 spin diffusion cannot significantly dephase these coherences. For the short-T2,H protons of a relatively immobile organic matrix, the heteronuclear dephasing rate depends simply on the heteronuclear second moment. Homonuclear interactions do not affect the dephasing, even though no homonuclear decoupling is applied, because long-range H1–X dipolar couplings approximately commute with short-range H1–H1 couplings, and heteronuclear recoupling periods are relatively short. This is shown in a detailed analysis based on interaction representations. The algorithm for simulating the dephasing data is described. The new method is demonstrated on a clay-polymer nanocomposite, diamond nanocrystals with protonated surfaces, and the bioapatite-collagen nanocomposite in bone, as well as pure clay and hydroxyapatite. The diameters of the nanoparticles in these materials range between 1 and 5nm. Simulations show that spherical particles of up to 10nm diameter can be characterized quite easily.
High-frequency dynamic nuclear polarization using mixtures of TEMPO and trityl radicals
Authors: Hu Kan-Nian , Bajaj Vikram S. , Rosay Melanie , Griffin Robert G.
Published: February 2007

In a previous communication [Hu et al., J. Am. Chem. Soc. 126, 10844 (2004)], an approach was demonstrated that improves the efficiency of the cross-effect polarization mechanism employed in high field dynamic nuclear polarization (DNP) experiments. Specifically, it was shown that tethering two TEMPO (2,2,6,6-tetramethylpiperidin-1-oxyl) radicals increases the electron-electron dipole coupling from ∼1MHz in solutions of monomeric TEMPO to ∼25MHz in a tethered biradical. The larger coupling resulted in an increase in the DNP enhancements by a factor of ∼3–4, from 45–50 to ∼165. Here, a second approach to improving the efficiency of the polarization process is described that involves approximately satisfying the matching condition ∣ω2e−ω1e∣=ωn, where ω2e and ω1e are two frequencies in the electron paramagnetic resonance (EPR) spectrum and ωn is the Larmor frequency of the nuclear spins being polarized. Specifically, in a mixture of TEMPO and trityl [tris (8-carboxy-2,2,6,6-tetramethyl(-d3)-benzo[1,2d:4,5-d’]bis(1,3)dithiol-4-yl) methyl] radicals, the intensity maxima in the EPR spectra of these two species are approximately separated by the H1 NMR frequency. In this case the frequency difference between the gyy value of TEMPO and the narrow pseudo-isotropic g-value of trityl is ∼224MHz and the H1 Larmor frequency is 211MHz. The optimal magnetic field for DNP using the mixtures was found to coincide with the trityl EPR resonance. At 90K and 5T, a mixture of 20mM TEMPO and 20mM trityl enhanced the H1 polarization by a factor of ∼160, an improvement over the enhancement of ∼50 with 40mM TEMPO. The reasons for the improvement are discussed and evidence is presented suggesting that DNP enhancement can be improved further by tethering TEMPO and trityl or two similar radicals.
Determination of elastic, piezoelectric, and dielectric constants of 0.67Pb(Mg1∕3Nb2∕3)O3-0.33PbTiO3 single crystal by Brillouin scattering
Authors: Xu Zhengkui , Siu G. G. , Liu Yulong , Luo Haosu
Published: February 2007

We report the determination of the complete set of elastic, piezoelectric, and dielectric constants of a 0.67Pb(Mg1∕3Nb2∕3)O3-0.33PbTiO3 (0.67PMN-0.33PT) single crystal by using Brillouin scattering in which all experimental data were collected from one [001]cub-poled crystal sample. The values of determined constants are similar to those previously determined from four crystal samples by using a hybrid method combining both ultrasonic and resonant techniques. The directional dependence of the compressional and shear modulus of the crystal in the (001) plane was investigated. A new weak broad peak appears at the low frequency side (∼18 GHz) between 45° and 65° scattering angles and the possible origins of the peak are discussed.