bluuebunny/crossref_metadata_2025 huggingface dataset:
Recovery of urokinase from integrated mammalian cell culture cryogel bioreactor and purification of the enzyme using p‐aminobenzamidine affinity chromatography
Authors: Bansal Vibha , Roychoudhury Pradip K. , Mattiasson Bo , Kumar Ashok
Published: June 2006

An integrated product recovery system was developed to separate urokinase from the cell culture broth of human kidney cells HT1080. Supermacroporous monolithic cryogels provided ideal matrices with respect to surface and flow properties for use as cell culture scaffold as well as for affinity chromatographic capture step of the enzyme in the integrated system. The urokinase was produced continuously in the reactor running for 4 weeks with continuous circulation of 500 ml of culture medium. The enzyme activity in the culture medium reached to 280 Plough units (PU)/mg protein. Cu(II)‐iminodiacetic acid (IDA)‐polyacrylamide (pAAm) cryogel column was used to capture urokinase by integrating with the gelatin‐coupled pAAm‐cryogel bioreactor for HT1080 cell culture. After removing the urokinase capture column from the integrated system the bound protein was eluted. The metal affinity capture step gave 4.5‐fold purification of the enzyme thus achieving a specific activity of 1300 PU/mg protein. The enzyme eluate from Cu(II)‐IDA‐pAAm cryogel capture column was further purified on benzamidine‐Sepharose affinity column. This step finally led to a homogeneous preparation of different forms of urokinase in two different elution peaks with a best urokinase activity of 13 550 PU/mg of protein. As compared to initial activity in the cell culture broth, about 26.2‐ and 48.4‐fold increase in specific activity was achieved with enzyme yields corresponding to 32% and 35% in two different peak fractions, respectively. Native electrophoresis and SDS–PAGE showed multiple protein bands corresponding to different forms of the urokinase, which were confirmed by Western blotting and zymography. Copyright © 2006 John Wiley & Sons, Ltd.
Extended application of a chiral stationary phase based on (+)‐(18‐crown‐6)‐2,3,11,12‐tetracarboxylic acid to the resolution of N‐(substituted benzoyl)‐α‐amino acid amides
Authors: Tan Guanghui , Xue Jin Ying , Hyun Myung Ho
Published: June 2006

A chiral stationary phase (CSP 1) based on (+)‐(18‐crown‐6)‐2,3,11,12‐tetracarboxylic acid was applied to the resolution of N‐(substituted benzoyl)‐α‐amino acid amides and esters. N‐(Substituted benzoyl)‐α‐amino acid amides were well resolved using a mixture of acetic acid‐triethylamine‐acetonitrile (0.01 : 0.05 : 100, v/v/v) as an optimum mobile phase while N‐(substituted benzoyl)‐α‐amino acid esters were not resolved at all. In contrast, both N‐(substituted benzoyl)‐α‐amino acid amides and esters were not resolved at all or resolved very poorly on another CSP (CSP 2), which lacks the two N–H hydrogens of the amide tethers of CSP 1. Among the substituents on the benzoyl group of analytes, the nitro group was the best for good resolution of analytes on CSP 1. From these results, the two N–H hydrogens of the amide tethers of CSP 1, the carbonyl oxygen of the amide group of analytes, and the nitro group on the benzoyl group of analytes were concluded to play significant roles in chiral recognition. In addition, various N‐(3,5‐dinitrobenzoyl)leucine amides with different lengths of N‐alkylamide chains were resolved on CSP 1 and N‐(3,5‐dinitrobenzoyl)leucine N‐propylamide was found to show the best chiral recognition in terms of the separation (α = 1.30) and the resolution factor (RS = 3.17).
Autocatalytic oxidation of hemin by acidic bromate
Authors: Rácz K. , Burger M. , Nagy‐Ungvarai ZS.
Published: June 2006

The kinetic behavior of the autocatalytic oxidation of hemin by acidic bromate was studied spectrophotometrically. The reaction was shown to differ significantly from both the acidic decomposition and the direct bromination of hemin. The dependence of its maximal rate on the reactant concentrations was established asv=k[hemin]0.8[BrO−3][H+]1.2. The value of the net rate constant was determined at two different ionic strengths. In the reaction path BrO.2radicals rather than elementary bromine play a crucial role. A mechanism is presented which takes into account the results of bromate chemistry as described for the Belousov–Zhabotinsky (BZ) reaction completed with the appropriate steps of hemin. On the basis of the suggested mechanism, model calculations were carried out which allowed to give an estimation for the rate constant of the reaction between hemin and BrO.2radicals. The results of computations account for the main experimental features of the reaction. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 503–509, 2006
The reaction of OH with acetaldehyde and deuterated acetaldehyde: Further insight into the reaction mechanism at both low and elevated temperatures
Authors: Taylor Philip H. , Yamada Takahiro , Marshall Paul
Published: June 2006

The pulsed laser photolysis/laser‐induced fluorescence technique has been used to conduct additional measurements of the gas‐phase CH3CHO + OH reaction. These measurements were conducted to verify the complex temperature dependence previously observed by the authors and to acquire mechanistic information about the reaction mechanism in the form of primary kinetic isotope effects. Primary kinetic isotope effect measurements at temperatures of 297, 383, 600, and 860 K indicate that H abstraction from the acetyl group dominates that of the methyl group at low to modest temperatures (⩽600 K) and H abstraction from the methyl group dominates that from the acetyl group at higher temperatures (860 K). A bi‐exponential © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 489–495, 2006
Interictal myoclonus with paroxysmal kinesigenic dyskinesia
Authors: Cochen De Cock Valerie , Bourdain Frederic , Apartis Emmanuelle , Trocello Jean Marc , Roze Emmanuel , Vidailhet Marie
Published: June 2006

We report a new association between interictal myoclonus and paroxysmal kinesigenic dyskinesia (PKD) in 2 patients. By definition, PKD is transient, but the overexcitability of the neuronal system that induces these attacks may be permanent. Interictal myoclonus could be a manifestation of permanent overexcitability. © 2006 Movement Disorder Society
Prognosis of Parkinson's disease: Time to stage III, IV, V, and to motor fluctuations
Authors: Sato Kenichi , Hatano Taku , Yamashiro Kazuo , Kagohashi Maki , Nishioka Kenya , Izawa Nana , Mochizuki Hideki , Hattori Nobutaka , Mori Hideo , Mizuno Yoshikuni
Published: June 2006

We report a long‐term outcome on a large cohort of Japanese patients with Parkinson's disease (PD). A total of 1,768 (793 men, 975 women) consecutive patients visited our clinic from 1 January 1989 to 31 December 2002. Among them, 1,183 patients (531 men, 652 women) came to our clinic within 5 years from the onset of disease and at the Hoehn & Yahr Stage III or less at the first visit. Long‐term outcome was evaluated in this subcohort of the patients. We examined the duration to reach Stage III, IV, and V, and the duration to develop wearing off and dyskinesia. Time to reach Stage III was slightly but significantly shorter in women, in that 23.8% of men and 35.3% of women reached Stage III by the end of the 5th year; 49.7% of men and 63.3% of women reached Stage III by the end of the 10th year, and 88.9% of men and 79.9% of women by the end of the 15th year (P < 0.001). Also, durations to develop wearing off and dyskinesia were shorter in women compared to men. These data suggest that the disease progression may be slightly faster for women. Young‐onset patients showed significantly longer duration to reach Stage III, IV, and V but shorter duration to develop wearing off and dyskinesia. Not many studies are available in the literature on the long‐term outcome of PD, and our data would be useful as a reference. © 2006 Movement Disorder Society
Improved multiplicity‐editing of HMBC NMR spectra
Authors: Benie Andrew J. , Sørensen Ole W.
Published: June 2006

A new improved multiplicity‐edited HMBC experiment is introduced that leads to better J cross‐talk suppression in the even (i.e. C + CH2 groups) and odd (i.e. CH + CH3 groups) subspectra. By combining data recorded with three different pulse sequences J cross‐talk becomes a second‐order effect in Δ1J, i.e. the deviation of an actual 1J coupling constant from the value 1J0 used in setting delays τ = (1J0)−1/2, which is adequate for most applications. As for the original multiplicity‐edited HMBC experiment, the improved experiment can be performed with a single excitation delay or implemented in a broadband version similar to broadband HMBC. Copyright © 2006 John Wiley & Sons, Ltd.
Identification of diffuse and focal brain lesions by clinical magnetic resonance spectroscopy
Authors: Kingsley Peter B. , Shah Tanmaya C. , Woldenberg Rona
Published: June 2006

The purpose of this paper is to facilitate the comparison of magnetic resonance (MR) spectra acquired from unknown brain lesions with published spectra in order to help identify unknown lesions in clinical settings. The paper includes lists of references for published MR spectra of various brain diseases, including pyogenic abscesses, encephalitis (herpes simplex, Rasmussen's and subacute sclerosing panencephalitis), neurocysticercosis, tuberculoma, cysts (arachnoid, epidermoid and hydatid), acute disseminated encephalomyelitis (ADEM), adrenoleukodystrophy (ALD), Alexander disease, Canavan's disease, Krabbe disease (globoid cell leukodystrophy), Leigh's disease, megalencephalic leukoencephalopathy with cysts, metachromatic leukodystrophy (MLD), Pelizaeus–Merzbacher disease, Zellweger syndrome, HIV‐associated lesions [cryptococcus, lymphoma, toxoplasmosis and progressive multifocal leukoencephalopathy (PML)], hydrocephalus and tuberous sclerosis. Each list includes information on the echo time(s) (TE) of the published spectra, whether a control spectrum is shown, whether the corresponding image and voxel position are shown and the patient ages if known. The references are listed in the approximate order of usefulness, based on spectral quality, number of spectra, range of echo times and whether the voxel positions are shown. Spectra of Zellweger syndrome, cryptococcal infection, toxoplasmosis and lymphoma are included, along with a spectrum showing propanediol (propylene glycol). Copyright © 2006 John Wiley & Sons, Ltd.
On the use of carbon nanotubes as reinforcing fillers for elastomeric materials
Authors: Bokobza Liliane , Kolodziej Mélanie
Published: June 2006

Rubber composites containing multiwall carbon nanotubes are investigated. The results are compared with those obtained with conventional carbon black. In each case, the level of reinforcement is assessed from the mechanical and equilibrium swelling behavior. The state of dispersion is evaluated from transmission electron and atomic force microscopy methods. Copyright © 2006 Society of Chemical Industry
Finding and documenting the specialization interface of an application framework
Authors: Hautamäki Juha , Koskimies Kai
Published: June 2006

This paper presents an approach to find, specify and use the specialization interface of an object‐oriented framework as a set of framework‐specific patterns. The approach is based on the assumption that the user tries to reuse a framework by setting meaningful goals in the context of their application and then achieves the goals by performing a sequence of programming tasks. The goals can be refined as informal specialization patterns, which are framework‐specific descriptions on how to reach a particular specialization goal. Furthermore, the obtained specialization patterns can be transformed into more precise specifications to enable tool support. As a result, the framework user can use both a cookbook‐like informal documentation and supporting tools to specialize the framework. Copyright © 2006 John Wiley & Sons, Ltd.
Scalable peer‐to‐peer networking architecture: DIVINE
Authors: Wong William Hak‐Lim , Ng Joseph Kee‐Yin
Published: June 2006

This paper describes the issues that are involved in designing and implementing a large‐scale cooperative object database server for a collaborative virtual environment. The focus of the paper is about the way to handle the distributing factors and the communication model among nodes within a collaborative virtual environment. Within the system, all objects are decentralized and scattered among three tiers of object databases. By limiting the knowledge and refining the tasks for each server, the network and processor workload can be reduced. The objective of the system is to provide a virtual environment for distributed computing that is k‐fault tolerant and subject to expansion without the interruption of services. Copyright © 2006 John Wiley & Sons, Ltd.
Anticoagulant Modulation of Blood Cells and Platelet Reactivity by Garlic Oil in Experimental Diabetes Mellitus
Authors: Ohaeri O.C. , Adoga G. I.
Published: June 2006

Multiple blood cell types and metabolic pathways involved in the modulation of platelet reactivity were investigated in streptozotocin-induced diabetic rats treated with garlic oil. Platelet counts of diabetic rats treated with garlic oil were significantly (P<0.01) reduced as compared to diabetic control rats. Garlic oil also increased the leucocyte counts of diabetic rats as compared to diabetic control rats. The significant (P<0.001) decreases by garlic oil of plasma concentration factors, V, VII, VIII: C, IX and X in diabetic rats may be interpreted to mean that there was a modulation of factor VII similar to that brought about by thrombin on factors V and VIII: C. This reversal of hypercoagulation through integrated biochemical reaction is suggestive of multicellular modulation of platelet reactivity, erythrocytes and neutrophils and the functional interactions between plasma coagulation factors and platelet cofactors.
Effects of Ginkgolide on the development of NOS and AChE positive neurons in the embryonic basal forebrain
Authors: Jin Guo‐Hua , Huang Zhen , Tan Xue‐Feng , Tian Mei‐Ling , Zhang Xin‐Hua , Qin Jian‐Bing , Xu Hui‐Jun , Yew D.T. , Mak Y.T.
Published: June 2006

Extract of Ginkgo biloba (EGb) has been therapeutically used for several decades to increase peripheral and cerebral blood flow so as to prevent cardiovascular and neurovascular diseases. However, the role of EGb in neuroprotective effects has received much attention recently. In this study, we investigated the effect of EGb on the development of NOS and AChE positive neurons in the rat embryonic basal forebrain. The results showed that treated with EGb, the OD of MTT staining analysis, and the numbers, the cell sizes and circumferences of NOS and AChE positive neurons were greatly promoted. These data suggest that EGb had similar effects of the neurotrophins such as NGF and BDNF in promoting the development of NOS and AChE positive neurons in the rat embryonic basal forebrain.
European public opinion and the Lisbon earthquake
Authors: ARAUJO ANA CRISTINA
Published: June 2006

At the end of November 1755, news of the Lisbon earthquake spread rapidly to all capital cities of Europe. Horrific reports gave rise to a wealth of sensational journalism. As Samuel Johnson and others attest, this was particularly marked in Great Britain. The catastrophe remained a popular subject of flysheets, newspapers, and engravings for months on end. The event was magnified many times over in the eyes and minds by the popular press, which led to forms of public distress. For the first time in the western world, the press, on the occasion of the Lisbon earthquake, helped create the illusion of proximity and unity between the peoples of different nations in Europe. As Voltaire said, ‘L'Europe ressemblait à une grande famille réunie après ses différences’.
On how not to be Lisbon if you want to be modern – Dutch reactions to the Lisbon earthquake
Authors: D'HAEN THEO
Published: June 2006

Contemporary Dutch reactions to the Great Lisbon Earthquake of 1755 mostly followed the general European pattern, explaining the event from a philosophical and theological stance. Still, the one Dutch poet to write extensively on the disaster gave a peculiarly Dutch twist to his interpretation. In essence, he used the Lisbon disaster to vent his views on the Dutch Republic's position at the middle of the eighteenth century, and to urge it to reclaim its rightful place in the scheme of things of what we in the meantime have come to call modernity. Some two centuries later, a major Dutch modernist poet again fastened upon the Lisbon earthquake to define himself in relation to that same modernity. However, he did so in a sense opposite to that of his eighteenth-century predecessor.
Historians, moral judgement and national communities: the Irish dilemma
Authors: CANNY NICHOLAS
Published: June 2006

This paper treats of the peculiarity of the Irish case. Professionalization of history came late to Ireland, and when it did happen, it was with a view to overcoming the inter-denominational and inter-communal point scoring that had energized most previous writing of Ireland's history. In tracing the further development of the history profession in Ireland, the paper alludes to the extent to which the posing of new questions and the employment of new methods were motivated by historical developments elsewhere in the western academic world. The outbreak of civil conflict in Northern Ireland inspired a new phase of introspective writing about Irish identity, sometimes given the semblance of universality through the invocation of post-colonial theory. This writing was usually presented in historical format, was composed mostly by academics employed by literature and social science departments, and was severely critical of what they described as the historical revisionism in which most professional historians in Ireland were believed to have engaged. It concludes with a consideration of how historians responded both to the challenge to their integrity and to various pressures to become more judgemental in writing about Ireland's past.
Miocene lateral extrusion in the inner western Alps revealed by dynamic fault analysis
Authors: Champagnac J. D. , Sue C. , Delacou B. , Tricart P. , Allanic C. , Burkhard M.
Published: June 2006

From early Miocene to the present‐day the core parts of the western European Alps experienced brittle extensional deformations, mostly in a strike‐parallel direction. Here we present new data constraining the brittle deformation of the Vanoise area (French Alps) and a synthesis of 312 paleostress tensors in the whole arc of the internal western Alps. The data show a continuous change in the direction of extension, from N065° (Simplon area), to N‐S (Vanoise area) and to NNW‐SSE (Briançon area). The abundance of orogen‐perpendicular σ3 axes increases from the north to the south. In the Briançonnais area, an extensional reactivation of the Basal Penninic Thrust seems to be the origin of the E‐W to NE‐SW oriented σ3. In light of these new data and the regional paleostress synthesis, we propose a predominant orogen‐parallel extension in the internal zone as a whole. This orogen‐parallel extension is related to the indentation/rotation of the Apulian microplate and to the opening of the Ligurian Sea during the lower‐middle Miocene. The locally observed orogen‐perpendicular extension is interpreted as an effect of the exhumation of the Internal Crystalline massifs, the uplift of the External Crystalline massifs and/or the present‐day geodynamics (postorogenic gravitational collapse). Some transcurrent tectonics, older than the extension in the Valais area and younger than the extension farther south is observed in the entire inner western Alps; strike‐slip movements are correlated with the Apulian rotation and local permutation of stress axes.
Nonpoint source solute transport normal to aquifer bedding in heterogeneous, Markov chain random fields
Authors: Zhang Hua , Harter Thomas , Sivakumar Bellie
Published: June 2006

Facies‐based geostatistical models have become important tools for analyzing flow and mass transport processes in heterogeneous aquifers. Yet little is known about the relationship between these latter processes and the parameters of facies‐based geostatistical models. In this study, we examine the transport of a nonpoint source solute normal (perpendicular) to the major bedding plane of an alluvial aquifer medium that contains multiple geologic facies, including interconnected, high‐conductivity (coarse textured) facies. We also evaluate the dependence of the transport behavior on the parameters of the constitutive facies model. A facies‐based Markov chain geostatistical model is used to quantify the spatial variability of the aquifer system's hydrostratigraphy. It is integrated with a groundwater flow model and a random walk particle transport model to estimate the solute traveltime probability density function (pdf) for solute flux from the water table to the bottom boundary (the production horizon) of the aquifer. The cases examined include two‐, three‐, and four‐facies models, with mean length anisotropy ratios for horizontal to vertical facies, ek, from 25:1 to 300:1 and with a wide range of facies volume proportions (e.g., from 5 to 95% coarse‐textured facies). Predictions of traveltime pdfs are found to be significantly affected by the number of hydrostratigraphic facies identified in the aquifer. Those predictions of traveltime pdfs also are affected by the proportions of coarse‐textured sediments, the mean length of the facies (particularly the ratio of length to thickness of coarse materials), and, to a lesser degree, the juxtapositional preference among the hydrostratigraphic facies. In transport normal to the sedimentary bedding plane, traveltime is not lognormally distributed as is often assumed. Also, macrodispersive behavior (variance of the traveltime) is found not to be a unique function of the conductivity variance. For the parameter range examined, the third moment of the traveltime pdf varies from negatively skewed to strongly positively skewed. We also show that the Markov chain approach may give significantly different traveltime distributions when compared to the more commonly used Gaussian random field approach, even when the first‐ and second‐order moments in the geostatistical distribution of the lnK field are identical. The choice of the appropriate geostatistical model is therefore critical in the assessment of nonpoint source transport, and uncertainty about that choice must be considered in evaluating the results.
Age and extent of the Yermak Slide north of Spitsbergen, Arctic Ocean
Authors: Winkelmann D. , Jokat W. , Niessen F. , Stein R. , Winkler A.
Published: June 2006

The extent of the Yermak Slide has been revised on the basis of new acoustic and detailed bathymetric data. The true geometry, with an affected area of at least 10,000 km2 and more than 2400 km3 of involved sedimentary material, puts the Yermak Slide among the largest exposed submarine slides worldwide, comparable to the Storegga Slide off central Norway. Details from the side's internal structure give evidence for one main slide event during MIS 3 followed by repeated minor events. The timing coincides with the transition of the Kapp Ekholm Interstadial into Glaciation G of Svalbard (Mangerud et al., 1998) and the buildup phase of the Svalbard‐Barents Sea Ice Sheet. Thus the slide occurred during a period of falling sea level, increasing ice volume, and, presumably, increasing glaciotectonic activity. The side's geometry and internal physical appearance point to a tectonically induced partial shelf collapse.
Glacial/interglacial variations in methanesulfonate (MSA) in the Siple Dome ice core, West Antarctica
Authors: Saltzman Eric S. , Dioumaeva Irina , Finley Brandon D.
Published: June 2006

Methanesulfonate (MSA) in the Siple Dome ice core is a record of the deposition of biogenic sulfur to the West Antarctic ice sheet covering the past 100 kyr. Siple Dome MSA levels were low during the last glacial maximum, and increased to higher Holocene levels with a several kyr lag relative to the deglacial warming. The positive correlation between MSA and temperature at Siple Dome is similar to that in Greenland ice cores (Renland, GISP2, and GRIP), and stands in contrast to the negative correlation observed at Vostok, East Antarctica. The Siple Dome MSA data suggest that the sign of the high latitude dust/sulfur/climate feedback is negative, at least for the Pacific sector of the high latitude Southern ocean. These results challenge the idea that fertilization by increased dust deposition led to widespread increased DMS emissions from this region of the glacial Southern Ocean.
Climatology of the midnight temperature maximum phenomenon at Arequipa, Peru
Authors: Faivre M. , Meriwether J. W. , Fesen C. G. , Biondi M. A.
Published: June 2006

A study of the midnight temperature maximum (MTM) climatology has been made for the low‐latitude station at Arequipa, Peru (16.2°S, 71.5°W) using Fabry‐Perot measurements for the period 1997–2001. Examination of the Arequipa nighttime temperature data after removal of the nocturnal cooling (as represented by the semiempirical NRLMSISE‐00 model) shows a Gaussian‐like time dependence with amplitudes between 20 and 200 K centered on 0400–0600 UT. A typical value of 50 to 75 K was found for data averaged over the nights from late March to early October, cloudy skies preventing measurements during summer months (November–February). These data show the MTM activity to fluctuate sporadically throughout the austral winter. Also evident are large variations of the offset between the observed temperatures and the MSIS model, with individual nightly offsets between ±200 K. Averaging these offsets over all nights for any 1 year and for all 5 years reduces the offset to a value of ∼20 K. The observed time for the occurrence of the MTM peak amplitude exhibits a seasonal variation; during winter solstice the peak typically occurs between 0500 and 0700 UT, later than during the fall and spring equinoxes, when the peak occurs between 0300 and 0500 UT. The variation of the MTM amplitude with day number shows a weak semiannual oscillation with peak values of 150–200 K near equinoxes and a small secondary maximum of 50 to 70 K near the winter solstice. Examination of the variation of the yearly‐averaged MTM amplitude between solar minimum and solar maximum show a slight trend featuring a ∼20 K reduction.
Equatorial bubbles as observed with GPS measurements over Pune, India
Authors: DasGupta A. , Paul A. , Ray S. , Das A. , Ananthakrishnan S.
Published: June 2006

Ionospheric total electron content (TEC) and scintillations have been recorded continuously since April 2003 using a dual‐frequency GPS receiver at Pune, India (geographic latitude 19.1°N, longitude 74.05°E; 24°N dip), situated in between the magnetic equator and the northern crest of the equatorial anomaly. The TEC often shows bite‐outs when severe amplitude scintillations are observed on the GPS L1 carrier level. The apparent duration of the bite‐outs may be different from the true east‐west duration, as observed with geostationary links, because of the presence of a relative velocity between the irregularity cloud and the satellite. The trajectory of a GPS satellite plays an important role in observing the bubble characteristics. The distributions of amplitude and duration of the bubbles have been obtained during the equinoctial months February through April of 2004. The median values are found to be 9 TEC units (1 TECU = 1016 el/m2) and 3.3 min, respectively. The range error at GPS L1 frequency corresponding to the median TEC depletion is 1.4 m, while that corresponding to the 95th percentile value is 4.5 m. An asymmetry in the east‐west walls of the bubble and sharp edges of the depletions resulting in high range error rates ∼30 cm/min has been noted.
Climate change, parasitism and the structure of intertidal ecosystems
Authors: Poulin R. , Mouritsen K.N.
Published: June 2006

Evidence is accumulating rapidly showing that temperature and other climatic variables are driving many ecological processes. At the same time, recent research has highlighted the role of parasitism in the dynamics of animal populations and the structure of animal communities. Here, the likely interactions between climate change and parasitism are discussed in the context of intertidal ecosystems. Firstly, using the soft-sediment intertidal communities of Otago Harbour, New Zealand, as a case study, parasites are shown to be ubiquitous components of intertidal communities, found in practically all major animal species in the system. With the help of specific examples from Otago Harbour, it is demonstrated that parasites can regulate host population density, influence the diversity of the entire benthic community, and affect the structure of the intertidal food web. Secondly, we document the extreme sensitivity of cercarial production in parasitic trematodes to increases in temperature, and discuss how global warming could lead to enhanced trematode infections. Thirdly, the results of a simulation model are used to argue that parasite-mediated local extinctions of intertidal animals are a likely outcome of global warming. Specifically, the model predicts that following a temperature increase of less than 4°C, populations of the amphipod Corophium volutator, a hugely abundant tube-building amphipod on the mudflats of the Danish Wadden Sea, are likely to crash repeatedly due to mortality induced by microphallid trematodes. The available evidence indicates that climate-mediated changes in local parasite abundance will have significant repercussions for intertidal ecosystems. On the bright side, the marked effects of even slight increases in temperature on cercarial production in trematodes could form the basis for monitoring programmes, with these sensitive parasites providing early warning signals of the environmental impacts of global warming.
Climate disruption and parasite–host dynamics: patterns and processes associated with warming and the frequency of extreme climatic events
Authors: Hudson P.J. , Cattadori I.M. , Boag B. , Dobson A.P.
Published: June 2006

Levels of parasitism and the dynamics of helminth systems is subject to the impact of environmental conditions such that we may expect long term increases in temperature will increase the force of infection and the parasite's basic reproduction number, R0. We postulate that an increase in the force of infection will only lead to an increase in mean intensity of adults when adult parasite mortality is not determined by acquired immunity. Preliminary examination of long term trends of parasites of rabbits and grouse confirm these predictions. Parasite development rate increases with temperature and while laboratory studies indicate this is linear some recent studies indicate that this may be non-linear and would have an important impact on R0. Warming would also reduce the selective pressure for the development of arrestment and this would increase R0 so that in systems like the grouse and Trichostrongylus tenuis this would increase the instability and lead to larger disease outbreaks. Extreme climatic events that act across populations appear important in synchronizing transmission and disease outbreaks, so it is speculated that climate disruption will lead to increased frequency and intensity of disease outbreaks in parasite populations not regulated by acquired immunity.
Grb2 Is a Negative Modulator of the Intrinsic Ras-GEF Activity of hSos1
Authors: Zarich Natasha , Oliva José Luis , Martínez Natalia , Jorge Rocío , Ballester Alicia , Gutiérrez-Eisman Silvia , García-Vargas Susana , Rojas José M.
Published: June 2006

hSos1 is a Ras guanine-nucleotide exchange factor. It was suggested that the carboxyl-terminal region of hSos1 down-regulates hSos1 functionality and that the intrinsic guanine-nucleotide exchange activity of this protein may be different before and after stimulation of tyrosine kinase receptors. Using different myristoylated hSos1 full-length and carboxyl-terminal truncated mutants, we show that Grb2 function accounts not only for recruitment of hSos1 to the plasma membrane but also for modulation of hSos1 activity. Our results demonstrate that the first two canonical Grb2 binding sites, inside the carboxyl-terminal region of hSos1, are responsible for this regulation. Following different approaches, such as displacement of Grb2 from the hSos1-Grb2 complex or depletion of Grb2 levels by small interfering RNA, we found that the full-length Grb2 proteins mediate negative regulation of the intrinsic Ras guanine-nucleotide exchange activity of hSos1.
Endocytosis of Cadherin from Intracellular Junctions Is the Driving Force for Cadherin Adhesive Dimer Disassembly
Authors: Troyanovsky Regina B. , Sokolov Eugene P. , Troyanovsky Sergey M.
Published: June 2006

The adhesion receptor E-cadherin maintains cell–cell junctions by continuously forming short-lived adhesive dimers. Here mixed culture cross-linking and coimmunoprecipitation assays were used to determine the dynamics of adhesive dimer assembly. We showed that the amount of these dimers increased dramatically minutes after the inhibition of endocytosis by ATP depletion or by hypertonic sucrose. This increase was accompanied by the efficient recruitment of E-cadherin into adherens junctions. After 10 min, when the adhesive dimer amount had reached a plateau, the assembly of new dimers stalled completely. These cells, in a striking difference from the control, became unable to disintegrate both their intercellular contacts and adhesive dimers in response to calcium depletion. The same effects, but after a slightly longer time course, were obtained using acidic media, another potent approach inhibiting endocytosis. These data suggest that endocytosis is the main pathway for the dissociation of E-cadherin adhesive dimers. Its inhibition blocks the replenishment of the monomeric cadherin pool, thereby inhibiting new dimer formation. This suggestion has been corroborated by immunoelectron microscopy, which revealed cadherin-enriched coated pit-like structures in close association with adherens junctions.
A Tale of Two Cultures: Contrasting Quantitative and Qualitative Research
Authors: Mahoney James , Goertz Gary
Published: June 2006

The quantitative and qualitative research traditions can be thought of as distinct cultures marked by different values, beliefs, and norms. In this essay, we adopt this metaphor toward the end of contrasting these research traditions across 10 areas: (1) approaches to explanation, (2) conceptions of causation, (3) multivariate explanations, (4) equifinality, (5) scope and causal generalization, (6) case selection, (7) weighting observations, (8) substantively important cases, (9) lack of fit, and (10) concepts and measurement. We suggest that an appreciation of the alternative assumptions and goals of the traditions can help scholars avoid misunderstandings and contribute to more productive “cross-cultural” communication in political science.
A Simple Multivariate Test for Asymmetric Hypotheses
Authors: Clark William Roberts , Gilligan Michael J. , Golder Matt
Published: June 2006

In this paper, we argue that claims of necessity and sufficiency involve a type of asymmetric causal claim that is useful in many social scientific contexts. Contrary to some qualitative researchers, we maintain that there is nothing about such asymmetries that should lead scholars to depart from standard social science practice. We take as given that deterministic and monocausal tests are inappropriate in the social world and demonstrate that standard multiplicative interaction models are up to the task of handling asymmetric causal claims in a multivariate, probabilistic manner. We illustrate our argument with examples from the empirical literature linking electoral institutions and party system size.
Food-limitation in a generalist predator
Authors: Rutz Christian , Bijlsma Rob G
Published: June 2006

Investigating food-limitation in generalist predators is difficult, because they can switch to alternative prey, when one of their staple prey becomes scarce. Apart from data on the dynamics of the predator population, a robust study requires: (i) a documentation of the predator's entire prey base; and (ii) an experimental or natural situation, where profitable dietary shifts are impossible, because several preferred prey species decline simultaneously. Here, we provide a detailed description of how food-supply has limited a generalist avian top predator, the northern goshawk
Accipiter gentilis
. In our study area, populations of several principal goshawk prey species crashed simultaneously during 1975–2000, whereas other extrinsic factors remained essentially unchanged. The breeding and non-breeding segments of the local goshawk population declined markedly, associated with a significant increase in nest failures. Brood size of successful pairs remained unaffected by changes in prey availability. Breeding recruitment ceased at a time when potential replacement birds (‘floaters’) were still present, providing a rare empirical demonstration of an ‘acceptance threshold’ in raptor territory choice. To investigate how goshawk diet changed in response to varying food-supplies, we make novel use of an analytical tool from biodiversity research—‘
a
bundance–
b
iomass–
c
omparison curves’ (ABC curves). With increasing levels of food-stress, the dominance of principal prey species in the diet decreased, and the number of small-bodied prey species increased, as did intra-guild predation. Our finding that breeder and non-breeder segments declined in concert is unexpected. Our results carry the management implication that, in food-limited raptor populations, externally induced breeder mortality can rapidly depress population size, as losses are no longer buffered when floaters reject breeding opportunities.
Body mass index, waist circumference and waist to hip ratio and change in sex steroid hormones: the Massachusetts Male Ageing Study
Authors: Derby Carol A. , Zilber Sophia , Brambilla Don , Morales Knashawn H. , McKinlay John B.
Published: June 2006

Objective  Cross‐sectional data suggest that obesity, particularly central obesity, may be associated with decreased production of sex steroid hormones in men. However, longitudinal hormone data on men in relation to obesity status are limited. Previous studies have not consistently demonstrated whether sex steroids are associated specifically to body mass index or to measures of central obesity. Our objective was to examine the relation of obesity (body mass index > 30 kg/m2), and of central obesity (waist circumference > 100 cm or waist to hip ratio > 0·95) to longitudinal change in sex steroid hormones in men.

Design  Prospective follow‐up of a population‐based sample of men in Boston.

Patients  Nine hundred forty‐two (942) men in the Massachusetts Male Ageing Study with complete anthropometry and hormone data at baseline (1987–1989, ages 40–70) and follow‐up (1995–1997).

Measurements  Free and total testosterone (FT and TT), dehydroepiandrosterone sulphate (DHEAS), and sex hormone‐binding globulin (SHBG) were assessed using standardized methods. Health behaviours and medical history were obtained by structured interview. Repeated measures regression was used to describe trends in steroid hormones and SHBG in relation to obesity status, adjusting for age, smoking, alcohol, comorbidities, and physical activity.

Results  Obesity was associated with decreased levels of total and free testosterone, and of SHBG at follow‐up relative to baseline. For any given baseline concentration of TT, FT or SHBG, follow‐up levels were lowest among men who remained obese or who became obese during follow‐up. This was true for all three indices of obesity. Central adiposity was associated with lower DHEAS levels at follow‐up, while elevated body mass index was not.

Conclusions  Obesity may predict greater decline in testosterone and SHBG levels with age. Central adiposity may be a more important predictor of decline in DHEAS than is body mass index.
Guidelines of the Pituitary Society for the diagnosis and management of prolactinomas
Authors: Casanueva Felipe F. , Molitch Mark E. , Schlechte Janet A. , Abs Roger , Bonert Vivien , Bronstein Marcello D. , Brue Thierry , Cappabianca Paolo , Colao Annamaria , Fahlbusch Rudolf , Fideleff Hugo , Hadani Moshe , Kelly Paul , Kleinberg David , Laws Edward , Marek Josef , Scanlon Maurice , Sobrinho Luis G. , Wass John A.H. , Giustina Andrea
Published: June 2006

In June 2005, an ad hoc Expert Committee formed by the Pituitary Society convened during the 9th International Pituitary Congress in San Diego, California. Members of this committee consisted of invited international experts in the field, and included endocrinologists and neurosurgeons with recognized expertise in the management of prolactinomas. Discussions were held that included all interested participants to the Congress and resulted in formulation of these guidelines, which represent the current recommendations on the diagnosis and management of prolactinomas based upon comprehensive analysis and synthesis of all available data.
Effects of search experience in a resource‐heterogeneous environment on the oviposition decisions of the seed beetle, Callosobruchus maculatus (F.)
Authors: YANG ROU‐LING , FUSHING HSIEH , HORNG SHWU‐BIN
Published: June 2006

Abstract 1. This study investigates how female seed beetles, Callosobruchus maculatus, distribute their eggs on various‐sized seeds when the size of seed was varied during the egg‐laying period.

2. Beetles were allowed to lay eggs on one of three arrays of 64 adzuki beans (Vigna angularis). Each array contained four size classes of seed, ranging from small (5.0–5.5 mm diameter) to large (6.5–7.0 mm), but differed in how they were distributed within the environment. In the most heterogeneous condition (the 64‐patch design), the four sizes were interspersed, while in the least heterogeneous condition (the four‐patch design) they were grouped into four separate blocks. Thus, a beetle exploring the 64‐patch design would frequently encounter all four seed sizes, whereas a beetle exploring the four‐patch design would only rarely encounter a change in bean size.

3. Beetles experiencing greater seed size heterogeneity were more likely to lay eggs on larger seeds, whereas those in the blocked condition were more likely to oviposit on small seeds. Beetle responses to seed size heterogeneity suggest that the degree of preference for large seeds depends on a female’s recent experience.

4. Female beetles exhibited size discrimination throughout their egg‐laying process; however, there was a trade‐off between seed size and egg discrimination (i.e. avoiding those seeds already containing developing eggs) in response to the change in fitness gained from either laying on larger seeds or lower egg‐load seeds during the egg‐laying process.

5. Our model provides the first evidence that evolving seed size discrimination ability is adaptive for the seed beetle with egg‐discrimination ability.
A northward shift of range margins in British Odonata
Authors: Hickling Rachael , Roy David B. , Hill Jane K. , Thomas Chris D.
Published: June 2006

Many species are predicted to shift their ranges to higher latitudes and altitudes in response to climate warming. This study presents evidence for 37 species of nonmigratory British dragonflies and damselflies shifting northwards at their range margins over the past 40 years, seemingly as a result of climate change. This response by an exemplar group of insects associated with fresh water, parallels polewards range changes observed in terrestrial invertebrates and other taxa.
Seventeen years of elevated CO2 exposure in a Chesapeake Bay Wetland: sustained but contrasting responses of plant growth and CO2 uptake
Authors: Rasse Daniel P. , Peresta Gary , Drake Bert G.
Published: June 2006

Increased atmospheric CO2 concentration (Ca) produces a short‐term stimulation of photosynthesis and plant growth across terrestrial ecosystems. However, the long‐term response remains uncertain and is thought to depend on environmental constraints. In the longest experiment on natural ecosystem response to elevated Ca, we measured the shoot‐density, biomass and net CO2 exchange (NEE) responses to elevated Ca from 1987 to 2003 in a Scirpus olneyi wetland sedge community of the Chesapeake Bay, MD, USA. Measurements were conducted in five replicated open‐top chambers per CO2 treatment (ambient and elevated). In addition, unchambered control plots were monitored for shoot density. Responses of daytime NEE, Scirpus plant biomass and shoot density to elevated Ca were positive for any single year of the 17‐year period of study. Daytime NEE stimulation by elevated Ca rapidly dropped from 80% at the onset of the experiment to a long‐term stimulation average of about 35%. Shoot‐density stimulation by elevated Ca increased linearly with duration of exposure (r2=0.89), exceeding 120% after 17 years. Although of lesser magnitude, the shoot biomass response to elevated Ca was similar to that of the shoot density. Daytime NEE response to elevated Ca was not explained by the duration of exposure, but negatively correlated with salinity of the marsh, indicating that this elevated‐Ca response was decreased by water‐related stress. By contrast, circumstantial evidence suggested that salinity stress increased the stimulation of shoot density by elevated Ca, which highlights the complexity of the interaction between water‐related stresses and plant community responses to elevated Ca. Notwithstanding the effects of salinity stress, we believe that the most important finding of the present research is that a species response to elevated Ca can continually increase when this species is under stress and declining in its natural environment. This is particularly important because climate changes associated with elevated Ca are likely to increase environmental stresses on numerous species and modify their present distribution. Our results point to an increased resilience to change under elevated Ca when plants are exposed to adverse environmental conditions.
Pregnancy, but not the allergic status, influences spontaneous and induced interleukin‐1β (IL‐1β), IL‐6, IL‐10 and IL‐12 responses
Authors: Amoudruz Petra , Minang Jacob Taku , Sundström Yvonne , Nilsson Caroline , Lilja Gunnar , Troye‐Blomberg Marita , Sverremark‐Ekström Eva
Published: June 2006

In this study, we investigated how pregnancy influences cytokine production in response to stimulation of the innate and the adaptive immune system, respectively. Peripheral blood mononuclear cells (PBMCs) from allergic (n = 44) and non‐allergic (n = 36) women were collected at three time‐points: during the third trimester, at delivery and at a non‐pregnant state 2 years after delivery. The production of interleukin‐1β (IL‐1β), IL‐6, IL‐10 and IL‐12 was measured by enzyme‐linked immunosorbent assay (ELISA) or enzyme‐linked immunospot assay (ELISPOT). The spontaneous cytokine production, and the response following stimulation with agents that primarily activate the adaptive part of the immune system [phytohaemagglutinin (PHA), allergen extracts from cat and birch], or lipopolysaccharide (LPS) that activate innate immunity was measured in vitro. There was a significantly higher spontaneous in vitro production of IL‐1β, IL‐6 and IL‐10 by PBMCs during pregnancy than 2 years after pregnancy, and this was not affected by the allergic status of the women. Conversely, in PHA‐stimulated cell cultures there was a lower production of IL‐10 and IL‐12 during pregnancy than 2 years after pregnancy. LPS‐induced IL‐6 levels were significantly lower in PBMCs obtained during pregnancy than at 2 years after pregnancy. In addition, we made the interesting observation that in allergic women total immunoglobulin E (IgE) levels were significantly lower 2 years after pregnancy compared to the levels during pregnancy. Taken together, our results indicate that while atopic allergy in women does not have a substantial effect on cytokine production, pregnancy has an obvious effect on the immune system in terms of cytokine production as well as on the total IgE levels.