bluuebunny/crossref_metadata_2025 huggingface dataset:
PERFORMING IDENTITIES: TWO CHINESE RITES IN SOUTHERN THAILAND
Authors: Hamilton Annette
Published: July 2008

The cults and ritual practices of the Sino-Thai communities of southern Thailand are a distinctive aspect of a region in which Chinese heritage has a high degree of social significance. Chinese came to the Malay Peninsula in several waves; many settlers arrived as early as the sixteenth century, and others flooded into the region to work in tin-mines and rubber plantations in the nineteenth century. Although now “Thai” in many respects, the descendants of Chinese immigrants in the south retain a distinctive identity, visibly expressed in the annual ritual cycle focused on specific rites and temples. These events provide a sense of connection to ancestral origins, but also make important statements about the contemporary position of Chinese descendants in a complex multiracial context. Tourism, both national and transnational, has played an important role in the expansion of ritual performance. During the capitalist boom years of the 1990s, elements of Chinese identity became a valued social marker in Thailand and some aspects of the southern cultural and ritual practices were adopted more widely, although most of the Sino-Thai descendants outside the south had little or no understanding of the origins or meaning of the practices. This paper examines rites performed annually in two southern Thai towns, investigating how they reflect complex negotiations of ethnic identity vis-à-vis national and regional contexts.
THE ESTABLISHMENT OF SILVER CURRENCY IN KYOTO
Authors: Nakajima Keiichi
Published: July 2008

The discovery in 1526 of the Iwami Ōmori silver deposits enabled Japan to become, by the 1540s, China's largest supplier of silver. This status was surpassed only in the 1570s, when large amounts of South American silver began to be delivered to southeast China via Manila. Despite the popularity of silver in the conduct of foreign trade, until the end of the sixteenth century it rarely played a part in Japanese domestic transactions. Even in Kyoto, capital of medieval Japan, it was gold, not silver, that was used for gifts and remittances. When for political reasons the Mōri clan donated the Ōmori silver mine to the court and Muromachi Bakufu, the flow of silver into Kyoto commenced in earnest. During the late 1560s gold assumed the characteristics of a fully functional currency, a development that paved the way for silver too, by the end of that decade, to become a major form of currency for domestic transactions involving imported items. During the 1570s usage of silver expanded to include other types of transactions. The 1580s and 1590s witnessed its firm establishment as currency, thus laying the foundation for the role of Kyoto in the early modern sphere of silver currency usage.
Cluster observations of the midaltitude cusp under strong northward interplanetary magnetic field
Authors: Hu R. , Bogdanova Y. V. , Owen C. J. , Foullon C. , Fazakerley A. N. , Rème H.
Published: July 2008

We report on a multispacecraft cusp observation lasting more than 100 min. We determine the cusp boundary motion and reveal the effect on the cusp size of the interplanetary magnetic field (IMF) changing from southward to northward. The cusp shrinks at the beginning of the IMF rotation and it reexpands at the rate of 0.40° invariant latitude per hour under stable northward IMF. On the basis of plasma signatures inside the cusp, such as counterstreaming electrons with balanced fluxes, we propose that pulsed dual lobe reconnection operates during the time of interest. SC1 and SC4 observations suggest a long‐term regular periodicity of the pulsed dual reconnection, which we estimate to be ∼1–5 min. Further, the distances from the spacecraft to the reconnection site are estimated on the basis of observations from three satellites. The distance determined using SC1 and SC4 observations is ∼15 RE and that determined from SC3 data is ∼8 RE. The large‐scale speed of the reconnection site sunward motion is ∼16 km s−1. We observe also a fast motion of the reconnection site by SC1, which provides new information about the transitional phase after the IMF rotation. Finally, a statistical study of the dependency of plasma convection inside the cusp on the IMF clock angle is performed. The relationship between the cusp stagnation, the dual lobe reconnection process, and the IMF clock angle is discussed.
A coastal current in winter: Autonomous underwater vehicle observations of the coastal current east of Cape Cod
Authors: Shcherbina Andrey Y. , Gawarkiewicz Glen G.
Published: July 2008

Evolution of the coastal current structure on the shallow continental shelf east of Cape Cod was studied using autonomous underwater vehicle (AUV) surveys and moored observations during the winters of 2005 and 2006. A coastally bounded plume of relatively fresh water, characteristic of a coastal current, persisted throughout both winters despite strong mixing. Nondimensional parameter analysis classified the plume as a bottom‐trapped gravity current over a moderately steep slope, placing it in the context of other buoyant coastal currents. The range of water properties within the coastal current, its spatial extent and temporal variability were characterized on the basis of the data from repeat hydrographic sections. Along‐shore freshwater transport was dominated by highly variable barotropic flow driven by local wind and basin‐wide pressure gradients. It eventually contributed substantially to the average southward along‐shore freshwater transport, estimated at 1.1 ± 0.3 × 103 m3 s−1 in February and 1.8 ± 0.4 × 103 m3 s−1 in the first half of March 2006. The contribution of baroclinic buoyancy‐driven freshwater transport was typically an order of magnitude lower during both winters. Despite the relative weakness of the baroclinic freshwater transport, the coastal current potentially had a major impact on water mass modification during the winter. Continual presence of the low‐salinity plume prevented the formation of cold dense water near the coast and its export offshore. The coastal current effectively isolated the inner‐shelf zone, reducing its potential role in ventilation of the intermediate layers of the Wilkinson Basin of the Gulf of Maine.
Lagrangian decomposition of the Deacon Cell
Authors: Döös K. , Nycander J. , Coward A. C.
Published: July 2008

The meridional overturning cells in the Southern Ocean are decomposed by Lagrangian tracing using velocity and density fields simulated with an ocean general circulation model. Particular emphasis is given to the Deacon Cell. The flow is divided into four major components: (1) water circling around Antarctica in the Antarctic Circumpolar Current (ACC), (2) water leaving the ACC toward the north into the three world oceans, (3) water coming from the north and joining the ACC, mainly consisting of North Atlantic Deep Water (NADW), and (4) interocean exchange between the three world oceans without circling around Antarctica. The Deacon Cell has an amplitude of 20 Sv, of which 6 Sv can be explained by the the east‐west tilt of the ACC, 5 Sv by the east‐west tilt of the subtropical gyre, and the remaining 9 Sv by the differences of the slope and depth of the southward transport of NADW and its return flow as less dense water. The diabatic or cross‐isopycnal Deacon Cell is only 2 Sv.
Linking global to regional models to assess future climate impacts on surface ozone levels in the United States
Authors: Nolte Christopher G. , Gilliland Alice B. , Hogrefe Christian , Mickley Loretta J.
Published: July 2008

We investigate the impact of climate change on future air quality in the United States with a coupled global/regional scale modeling system. Regional climate model scenarios developed by dynamically downscaling outputs from the GISS GCM are used by CMAQ to simulate present air pollution climatology, and modeled surface ozone mixing ratios are compared with recent observations. Though the model accurately simulates ozone in the northeast U.S. and in central California, a positive bias of 10–15 ppb exists throughout most of the central and southeast U.S. The model is also applied to a simulated 2050 climate based on the IPCC A1B greenhouse gas scenario. Two future simulations are conducted, one with anthropogenic emissions held at 2001 levels, and one with anthropogenic emissions reduced in accordance with the A1B scenario. Without ozone precursor emissions changes, increases from 2–5 ppb in summer mean 8‐h ozone mixing ratios are projected in Texas and parts of the eastern U.S., while high ozone episodes become more frequent. Increases of 2–8 ppb during the autumn are predicted over a large area in the central and southwest U.S., suggesting a lengthening of the ozone season. These increases within the regional modeling domain are predicted despite large decreases in the future global background ozone mixing ratio. Substantial decreases exceeding 15 ppb during the summer are predicted for the future reduced emissions case. A sensitivity test conducted with 30% higher methane mixing ratio yields widespread ozone increases of 0.5–2 ppb, an effect larger than that of climate‐induced increases in isoprene emissions, demonstrating the need to consider changes in methane levels alongside climate change when simulating future air quality.
Annual and semiannual TEC effects at low solar activity in midlatitude Atlantic region based on TOPEX
Authors: Meza A. , Natali M. P.
Published: July 2008

The aim of this work is the analysis of the annual and semiannual effects in the total electron content (TEC) of the terrestrial atmosphere during low solar activity. The region of study is the Atlantic Ocean at mid geomagnetic latitudes. Spatial and temporal ionospheric variability are investigated from TOPEX/POSEIDON (T/P) altimetry data. To correct the Earth ionospheric delay on the radar pulse, the satellite's altimeter makes measurements in two channels. The difference between both measurements yields the estimated values of TEC from lower part of the ionosphere up to the height of the satellite. Time series of vertical TEC from T/P, converted on a regular 1° × 1° grid, are studied making use of Principal Component Analysis. Simulated data from a climatological model of the ionosphere (IRI) are computed to improve our analysis, mainly regarding the data time coverage. The behavior of TEC variations at four different hours of the day are analyzed, highlighting particular characteristics associated with every period (morning, noon, afternoon and night) and with the geomagnetic region.
Model bias correction for dust storm forecast using ensemble Kalman filter
Authors: Lin Caiyan , Zhu Jiang , Wang Zifa
Published: July 2008

First attempt to correct model bias in a dust transport model using ensemble Kalman filter (EnKF) assimilation targeting heavy dust episodes during the period of 15–24 March 2002 over north China is successfully performed. The uncertainty of dust emissions and surface wind fields are taken into account individually and simultaneously to correct their biases. The 24‐h surface forecasts are significantly improved with the root mean square error reduced by more than 45% on 20 March and by 50% on 21 March after correcting the biases. The results indicate that there are high biases due to the dust emissions and surface wind fields. These biases converge to the values similar with those obtained in previous sensitivity analyses indicating that the EnKF can accurately correct the bias. The corrected total dust emissions are decreased more than 33%. However, when considered simultaneously, they do not converge to the same results as those considered individually. This indicates that the two biases can compensate for each other in terms of predicted surface dust concentration.
Arctic Oscillation and the autumn/winter snow depth over the Tibetan Plateau
Authors: Lü Jun‐Mei , Ju Jian‐Hua , Kim Seong‐Joong , Ren Ju‐Zhang , Zhu Yu‐Xiang
Published: July 2008

The present study examines the relationship between the Arctic Oscillation (AO) and the autumn/winter snow depth over the Tibetan Plateau. Results show that there exists significant correlation between the AO and the Tibetan Plateau snow depth on interdecadal timescale. The AO and the snow depth over the Tibetan Plateau experienced interdecadal regime shift in the late 1970s. Before the late 1970s when the AO was in its interdecadal negative phase, the snow depth over the Tibetan Plateau increased in fall and then decreased in the following winter. Conversely, when the AO has entered its interdecadal positive phase since the early 1980s, the snow depth decreased in fall, but increased in winter. The vertical propagation of Rossby waves is proposed to explain the physical process linking the AO with the snow depth. Anomalously excessive fall snow depth over the Tibetan Plateau amplifies orographically forced upward stationary waves. The snow‐forced changes in stratosphere are not identified until later in the winter season when Rossby waves propagate into the stratosphere and the AO becomes negative. In winter, when the troposphere and stratosphere are actively coupled, the downward propagation of Rossby waves associated with the positive AO phase modulates the atmospheric circulation in the troposphere, and causes the abnormal increase of snow depth over the Tibetan Plateau.
Aerosol light scattering effect on terrestrial plant productivity and energy fluxes over the eastern United States
Authors: Matsui Toshihisa , Beltrán‐Przekurat Adriana , Niyogi Dev , Pielke Roger A. , Coughenour Michael
Published: July 2008

This study reports the first regional‐scale assessment of aerosol effects on plant productivity and surface energy fluxes over the eastern United States. Analysis is conducted using an established modeling framework, which is composed of a regional land surface model, regional daily aerosol optical depth (AOD) estimates, and meteorological forcings. The sensitivity experiments were conducted from May to September in 2000 and 2001 over the eastern United States with and without the aerosol light scattering effect. Results show that the aerosol light scattering effect results in enhanced productivity for high‐LAI and optimum temperature environments under cloudless‐sky conditions around noon, while it results in least productive for low‐LAI, low‐temperature environments under cloud‐sky conditions in early morning or late afternoon. As a result, domain‐averaged plant productivities, measured as net primarily production, are changed by −0.71 g C m−2 (−0.09%) in 2000 and +5.00 g C m−2 (+0.5%) in 2001. These responses of plant productivity and photosynthesis to the aerosol light scattering effect uniquely modulate the surface flux as follows. The aerosol light scattering effect reduces the surface downwelling solar radiation (14.9 W m−2 in 2000 and 16.0 W m−2 in 2001) and net radiation in vegetation canopy, but simultaneously increases the photosynthesis and stomatal conductance. Consequently, surface latent heat flux (transpiration and evaporation) is reduced by a small amount particularly over the forests, while aerosol loading often results in larger reduction in the sensible heat flux. For the whole domain, latent heat flux is changed by −3.10 W m−2 (−2.1%) in 2000 and −3.12 W m−2 (−2.1%) in 2001, sensible heat flux is changed by −7.57 W m−2 (−12.9%) in 2000 and −8.36 W m−2 (−11.3%) in 2001, and surface skin temperature is changed by −0.25 K (−0.1%) in 2000 and −0.27 K (−0.1%) in 2001.
A Catchment‐Based Hydrologic and Routing Modeling System with explicit river channels
Authors: Goteti Gopi , Famiglietti James S. , Asante Kwabena
Published: July 2008

In this paper, we present a macroscale hydrologic modeling system with an explicit representation of storage and movement of water in river channels and floodplains. The overall modeling system, called the Catchment‐Based Hydrologic and Routing Modeling System (CHARMS), is composed of a land surface model and a river routing model that operate on a network of hydrologic catchments (or watersheds). The land surface model in CHARMS is based on the National Center for Atmospheric Research Community Land Model. The river routing model in CHARMS generates river discharge by transporting runoff generated by the catchment‐based CLM through the river network. The routing model uses information on channel cross‐section geometry, derived from the 90 m Shuttle Radar Topography Mission digital elevation model, to simulate river discharge and the associated flow depth and inundation width. CHARMS was implemented over the Wabash River basin in the central United States (drainage area 72282 km2), and simulated streamflow was validated using daily observations. Simulated flow depth and inundation extent generally followed seasonal variations in observed flooding and droughts. Limitations of some of the assumptions and scaling factors used in this study and the issues that need to be addressed for a continental‐ or global‐scale implementation of CHARMS are discussed. This paper serves as the foundation for a catchment‐based, global land surface modeling framework that could incorporate spatiotemporal variations in surface water bodies, as well as satellite measurements of these variations.
Typhoon induced upper ocean cooling off northeastern Taiwan
Authors: Tsai Yaling , Chern Ching‐Sheng , Wang Joe
Published: July 2008

The ocean cooling off northeastern Taiwan induced by typhoons is complicated by the presence of the continental shelf of the East China Sea and the Kuroshio. The cooling is primarily due to the upwelling of the Kuroshio's subsurface water, which accompanies the Kuroshio's intrusion onto the shelf, rather than the entrainment mixing generated by the wind. The Kuroshio's intrusion in this region has a seasonal variation, being more substantial in winter than in summer. Previous studies found that the winter northeasterly monsoon creates an intrusion‐favored flow pattern, while the reversed summer monsoon opposes it. This study found that the strong northeast wind, accompanied by a typhoon along a certain path, could significantly alter the circulations on the shelf. An intrusion event will be triggered via a similar mechanism as induced by the winter monsoon, but at a faster pace. A numerical study and observation data are provided to illustrate this mechanism.
Aseismic slip and fault‐normal strain along the central creeping section of the San Andreas fault
Authors: Rolandone F. , Bürgmann R. , Agnew D. C. , Johanson I. A. , Templeton D. C. , d'Alessio M. A. , Titus S. J. , DeMets C. , Tikoff B.
Published: July 2008

We use GPS data to measure the aseismic slip along the central San Andreas fault (CSAF) and the deformation across adjacent faults. Comparison of EDM and GPS data sets implies that, except for small‐scale transients, the fault motion has been steady over the last 40 years. We add 42 new GPS velocities along the CSAF to constrain the regional strain distribution. Shear strain rates are less than 0.083 ± 0.010 μstrain/yr adjacent to the creeping SAF, with 1–4.5 mm/yr of contraction across the Coast Ranges. Dislocation modeling of the data gives a deep, long‐term slip rate of 31–35 mm/yr and a shallow (0–12 km) creep rate of 28 mm/yr along the central portion of the CSAF, consistent with surface creep measurements. The lower shallow slip rate may be due to the effect of partial locking along the CSAF or reflect reduced creep rates late in the earthquake cycle of the adjoining SAF rupture zones.
Dependence of the IMF sector structure on the solar dipole tilt angle
Authors: Du A. M. , Xu W. Y. , Feng X. S.
Published: July 2008

The quasiperiodic variations of the interplanetary magnetic field (IMF) sector structure at the ACE satellite (L1) are investigated using power spectrum analysis. It appears that the two‐sector structure of the IMF dominates during the solar maximum, lasting 3 years from 2000 through 2003, and the four‐sector structure dominates during the solar activity minimum. A possible explanation is introduced for this phenomenon in which the IMF sector structures vary with the tilt angle of the heliospheric current sheet (HCS) with respect to the solar rotation axis. During the solar activity maximum, the HCS is perpendicular to the ecliptic plane. Therefore the spacecrafts at L1 point are expected to pass through the HCS only twice in one solar rotation, which gives rise to the observed two‐sector structure of the IMF. On the other hand, during the solar activity minimum, the HCS is nearly parallel to the ecliptic plane, and the polarity of IMF Bx changes several times in one solar rotation due to the wavy nature of the HCS, which may lead to the observed four‐sector structure.
Annexin‐A1: a pivotal regulator of the innate and adaptive immune systems
Authors: D'Acquisto F , Perretti M , Flower R J
Published: July 2008

The glucocorticoids are the most potent anti‐inflammatory drugs that we possess and are effective in a wide variety of diseases. Although their action is known to involve receptor mediated changes in gene transcription, the exact mechanisms whereby these bring about their pleiotropic action in inflammation are yet to be totally understood. Whilst many different genes are regulated by the glucocorticoids, we have identified one particular protein—annexin A1 (Anx‐A1)—whose synthesis and release is strongly regulated by the glucocorticoids in many cell types. The biology of this protein, as revealed by studies using transgenic animals, peptide mimetics and neutralizing antibodies, speaks to its role as a key modulator of both of the innate and adaptive immune systems. The mechanism whereby this protein exerts its effects is likely to be through the FPR receptor family—a hitherto rather enigmatic family of G protein coupled receptors, which are increasingly implicated in the regulation of many inflammatory processes. Here we review some of the key findings that have led up to the elucidation of this key pathway in inflammatory resolution.

British Journal of Pharmacology (2008) 155, 152–169; doi:10.1038/bjp.2008.252; published online 21 July 2008
Investigation of Debio 025, a cyclophilin inhibitor, in the dystrophicmdxmouse, a model for Duchenne muscular dystrophy
Authors: Reutenauer J , Dorchies O M , Patthey‐Vuadens O , Vuagniaux G , Ruegg U T
Published: July 2008

Background and purpose:

Duchenne muscular dystrophy (DMD) is a severe muscle wasting disorder caused by the absence of the cytoskeletal protein dystrophin. This leads to muscle cell death accompanied by chronic inflammation. Cyclosporin A (CsA) is a powerful immunosuppressive drug, which has been proposed for DMD treatment. CsA also directly regulates the mitochondrial permeability transition pore (mPTP), which participates in cell death pathways through the inhibition of cyclophilin D. Here, we evaluated whether Debio 025, a cyclophilin inhibitor with no immunosuppressive activity, improves the dystrophic condition in a mouse model of DMD, through regulation of mPTP.

Experimental approach:

The potency of Debio 025 to protect mouse dystrophic cells against mitochondria‐mediated death was assessed by caspase‐3 activity and calcium retention capacity assays.Mdx5Cvmice (3‐week‐old) were treated daily by gavage for 2 weeks with Debio 025 (10, 30 or 100 mg kg−1), CsA (10 mg kg−1) or placebo. The effects on muscle necrosis and function were measured.

Key results:

In vitroinvestigations showed protective effect of low concentrations of Debio 025 against cell death. Histology demonstrated that Debio 025 partially protected the diaphragm and soleus muscles against necrosis (10 and 100 mg kg−1, respectively). Hindlimb muscles from mice receiving Debio 025 at 10 mg kg−1relaxed faster, showed alteration in the stimulation frequency‐dependent recruitment of muscle fibres and displayed a higher resistance to mechanical stress.

Conclusions and implications:

Debio 025 partially improved the structure and the function of the dystrophic mouse muscle, suggesting that therapies targeting the mPTP may be helpful to DMD patients.

British Journal of Pharmacology(2008)155, 574–584; doi:10.1038/bjp.2008.285; published online 21 July 2008
YC‐1 induces apoptosis of human renal carcinoma A498 cells in vitro and in vivo through activation of the JNK pathway
Authors: Wu S Y , Pan S L , Chen T H , Liao C H , Huang D Y , Guh J H , Chang Y L , Kuo S C , Lee F Y , Teng C M
Published: July 2008

Background and purpose:

The aim of this study was to elucidate the mechanism of YC‐1{3‐(5′‐hydroxy methyl‐2′‐furyl)‐1‐benzylindazole}‐induced human renal carcinoma cells apoptosis and to evaluate the potency of YC‐1 in models of tumour growth in mice.

Experimental approach:

YC‐1‐mediated apoptosis was assessed by analysis of MTT, SRB, DAPI staining and flow cytometry analysis. Knockdown of JNK protein was achieved by transient transfection using siRNA. The mechanisms of action of YC‐1 on different signalling pathways involved were studied using western blot. Fas clustering was analysed by confocal microscopy and in vivo efficacy was examined in a A498 xenograft model.

Key results:

YC‐1 displayed cytotoxicity in renal carcinoma cells at 10−7–10−8 M. Increased condensation of chromatin was observed and an increase in the cell population in subG1 phase. Moreover, YC‐1 triggered mitochondria‐mediated and caspase‐dependent pathways. YC‐1 significantly induced Fas ligand expression, but did not modify either the protein levels of death receptors or ligands. In addition, Fas clustering in cells responsive to YC‐1 was observed, suggesting involvement of a Fas‐mediated pathway. Furthermore, YC‐1 markedly induced phosphorylation of JNK and a JNK inhibitor, SP600125, and siRNA JNK1/2 significantly reversed YC‐1‐induced cytotoxicity and protein expression. We suggest that YC‐1 induced JNK phosphorylation, the upregulation of FasL and Fas receptor clustering to promote the activation of caspases 8 and 3, resulting in apoptosis. Finally, we demonstrated the antitumour effect of YC‐1 in vivo.

Conclusions and implications:

These data suggest that YC‐1 is a good candidate for development as an anticancer drug.

British Journal of Pharmacology (2008) 155, 505–513; doi:10.1038/bjp.2008.292; published online 21 July 2008
α1‐Adrenoceptors in the lateral septal area modulate food intake behaviour in rats
Authors: Scopinho A A , Resstel L B M , Corrêa F M A
Published: July 2008

Background and purpose:

Control of food intake is a complex behaviour which involves many interconnected brain structures. The present work assessed if the noradrenergic system in the lateral septum (LS) was involved in the feeding behaviour of rats.

Experimental approach:

In the first protocol, the food intake of rats was measured. Then non‐food‐deprived animals received either 100 nL of 21 nmol of noradrenaline or vehicle unilaterally in the LS 10 min after local 10 nmol of WB4101, an α1‐adrenoceptor antagonist, or vehicle. In the second protocol, different doses of WB4101 (1, 10 or 20 nmol in 100 nL) were microinjected bilaterally into the LS of rats, deprived of food for 18 h and food intake was compared to that of satiated animals.

Key results:

One‐sided microinjection of noradrenaline into the LS of normal‐fed rats evoked food intake, compared with vehicle‐injected control animals, which was significantly reduced by α1‐adrenoceptor antagonism. In a further investigation, food intake was significantly higher in food‐deprived animals, compared to satiated controls. Pretreatment of the LS with WB4101 reduced food intake in only food‐deprived animals in a dose‐related manner, suggesting that the LS noradrenergic system was involved in the control of food intake.

Conclusion and implications:

Activation by local microinjection of noradrenaline of α1‐adrenoceptors in the LS evoked food intake behaviour in rats. In addition, blockade of the LS α1‐adrenoceptors inhibited food intake in food‐deprived animals, suggesting that the LS noradrenergic system modulated food intake behaviour and satiation.

British Journal of Pharmacology (2008) 155, 752–756; doi:10.1038/bjp.2008.295; published online 21 July 2008;
Biosynthesis of H2S is impaired in non‐obese diabetic (NOD) mice
Authors: Brancaleone V , Roviezzo F , Vellecco V , De Gruttola L , Bucci M , Cirino G
Published: July 2008

Background and purpose:

Hydrogen sulphide (H2S) has been involved in cardiovascular homoeostasis but data about its role in animal models of diabetic pathology are still lacking. Here, we have analysed H2S signalling in a genetic model of diabetes, the non‐obese diabetic (NOD) mice.

Experimental approach:

NOD mice exhibit a progressive endothelial dysfunction characterized by a reduced reactivity of blood vessels as diabetes develops. NOD mice were divided into three groups according to different glycosuria values: NOD I, NOD II and NOD III. Age‐matched non‐obese resistant (NOR) mice were used as controls. H2S levels in plasma and aortic tissue were measured. Functional studies in aorta were carried out in isolated organ baths using both an exogenous source of H2S (NaHS) and the metabolic precursor (L‐cysteine). Real time PCR and western blot analysis were also carried out on aortic tissues.

Key results:

NOD mice exhibited a progressive reduction of H2S plasma levels, which paralleled disease severity. L‐cysteine‐induced H2S production by aortic tissues was also progressively reduced. L‐cysteine‐induced vasorelaxation was significantly reduced in NOD mice while NaHS‐induced relaxation was unaffected. ODQ (guanylate cyclase inhibitor), L‐NAME (NO synthase inhibitor) or PAG, an inhibitor of cystathionine‐γ‐lyase (CSE) inhibited H2S production induced by L‐cysteine.

Conclusions and implications:

In NOD mice, endogenous H2S production is significantly impaired. Also, the ability of isolated aorta to respond to exogenous H2S is enhanced and endothelium‐derived NO appears to be involved in the enzymatic conversion of L‐cysteine into H2S.

British Journal of Pharmacology (2008) 155, 673–680; doi:fn1; published online 21 July 2008
Inhibition of cyclooxygenases 1 and 2 by the phospholipase‐blocker, arachidonyl trifluoromethyl ketone
Authors: Leis H J , Windischhofer W
Published: July 2008

Background and purpose:

Arachidonyl trifluoromethyl ketone (ATK) is widely used as an inhibitor of cytosolic group IV phospholipase A2(cPLA2) and calcium‐independent group VI phospholipase A2(iPLA2). ATK thus reduces arachidonic acid (AA) substrate for cyclooxygenase (COX; also known as prostaglandin H synthase) and attenuates prostaglandin (PG) synthesis. It has been shown previously, that ATK blocks thromboxane B2production induced by exogenous AA in human platelets. It remains, however, unknown whether ATK also directly modulates the activity of cyclooxygenase (COX).

Experimental approach:

Time courses for inhibition of COX by ATK was obtained using osteoblast‐like MC3T3‐E1 cells, with exogenous AA as substrate and the pure enzymes COX‐1 and COX‐2. PGE2was measured by GC‐MS.

Key results:

ATK was a potent inhibitor of COX‐1 and COX‐2 with IC50values of 0.5 and 0.1 μMin MC3T3‐E1 cells and of 1.7 and 2.6 μMusing the pure enzymes. Inhibition was reversible, with slow‐ and tight‐binding characteristics. The arachidonyl carbon chain was essential, as the saturated palmitoyl analogue had no effect.

Conclusions and implications:

Attenuation of PG synthesis by ATK is taken to be the consequence of PLA2inhibition and the findings of many studies are interpreted on that basis. If there are, however, alternative routes for AA liberation (such as phospholipase C/diacyl glycerol lipase or phospholipase D), this interpretation can lead to false conclusions. As ATK is a widely used and important pharmacological tool in eicosanoid research, knowledge of its interactions with other major enzymes of the cascade is of considerable importance.

British Journal of Pharmacology(2008)155, 731–737; doi:10.1038/bjp.2008.304; published online 21 July 2008
Oculomotor Nucleus
Authors:   Allen Institute for Brain Science, Burnell Josh , Ng Lydia , Guillozet-Bongaarts Angela
Published: July 2008

This report contains a gene expression summary of the oculomotor nucleus, derived from the Allen Brain Atlas (ABA) in situ hybridization mouse data set. The structure's location and morphological characteristics in the mouse brain are described using the Nissl data found in the Allen Reference Atlas. Using an established algorithm, the expression values of the oculomotor nucleus were compared to the values of the macro/parent-structure, in this case the midbrain, for the purpose of extracting regionally selective gene expression data. The genes with the highest ranking selectivity ratios were manually curated and verified. 50 genes were then selected and compiled for expression characterization. The experimental data for each gene may be accessed via the links provided; additional data in the sagittal plane may also be accessed using the ABA. Correlations between gene expression in the oculomotor nucleus and the rest of the brain, across all genes in the coronal dataset (~4300 genes), were derived computationally. A gene ontology table (derived from DAVID Bioinformatics Resources 2007) is also included, highlighting possible functions of the 50 genes selected for this report.
Dentate Gyrus
Authors:   Allen Institute for Brain Science, Dalley Rachel , Ng Lydia , Guillozet-Bongaarts Angela
Published: July 2008

This report contains a gene expression summary of the dentate gyrus (DG), derived from the Allen Brain Atlas (ABA) in situ hybridization mouse data set. The structure's location and morphological characteristics in the mouse brain are described using the Nissl data found in the Allen Reference Atlas. Using an established algorithm, the expression values of the dentate gyrus were compared to the values of the macro/parent-structure, in this case the hippocampal region, for the purpose of extracting regionally selective gene expression data. The genes with the highest ranking selectivity ratios were manually curated and verified. 50 genes were then selected and compiled for expression characterization. The experimental data for each gene may be accessed via the links provided; additional data in the sagittal plane may also be accessed using the ABA. Correlations between gene expression in the dentate gyrus and the rest of the brain, across all genes in the coronal dataset (~4300 genes), were derived computationally. A gene ontology table (derived from DAVID Bioinformatics Resources 2007) is also included, highlighting possible functions of the 50 genes selected for this report.
Bioconversion of small molecules by cytochrome P450 species expressed in Escherichia coli
Authors: Uno Tomohide , Okamoto Sota , Masuda Satoko , Itoh Atsushi , Uno Yuichi , Nakamura Masahiko , Kanamaru Kengo , Yamagata Hiroshi , Imaishi Hiromasa
Published: July 2008

P450 (cytochrome P450) enzymes catalyse the mono‐oxygenation of a wide range of compounds such as steroids, fatty acids, vitamins and drugs. In the present paper we demonstrate a system for bioconverting diverse compounds [flavanone, DHEA (dehydroepiandrosterone) and 7‐ethoxycoumarin] using P450 species expressed in Escherichia coli. First, we expressed four P450 species: rabbit CYP2B (P450 family 2, subfamily B), fruitfly (Drosophila) CYP317A, rat CYP3A23 and mouse CYP2J5. Next, we added substrates directly to the incubation medium. The resulting metabolites were extracted and analysed by HPLC and spectrofluorimetry. The first substrate, 7‐ethoxycoumarin, was de‐ethylated by CYP2B; CYP2J5 and CYP3A23 showed weak activity, and CYP317A had no activity for 7‐ethoxycoumarin. We next used flavanone, a flavonoid, as a substrate for these four P450 species and other P450 species expressed previously. As a result, CYP2B, CYP2C43 and CYP2C29 catalysed flavanone 2‐hydroxylation. CYP2A5 catalysed 2‐ and 4‐hydroxylations. Finally, to produce diverse modified compounds, variants of CYP2A5 with point mutations were incubated with a steroid (DHEA) and an antioxidant (flavanone) in vivo. HPLC analysis indicated that two P450 species produced a 7‐β‐hydroxy‐DHEA and two P450 species produced a 2‐α‐hydroxy‐DHEA. Four P450 species catalysed flavanone 2‐ and 4‐hydroxylations. These results indicate that bioconversion by P450 is a useful technique to modify small molecules (steroids, coumarin and flavanone) and produce new, diverse hydroxylated compounds, which could be used for high‐throughput screening for drug discovery.
Viral detection by electron microscopy: past, present and future
Authors: Roingeard Philippe
Published: July 2008

Viruses are very small and most of them can be seen only by TEM (transmission electron microscopy). TEM has therefore made a major contribution to virology, including the discovery of many viruses, the diagnosis of various viral infections and fundamental investigations of virus—host cell interactions. However, TEM has gradually been replaced by more sensitive methods, such as the PCR. In research, new imaging techniques for fluorescence light microscopy have supplanted TEM, making it possible to study live cells and dynamic interactions between viruses and the cellular machinery. Nevertheless, TEM remains essential for certain aspects of virology. It is very useful for the initial identification of unknown viral agents in particular outbreaks, and is recommended by regulatory agencies for investigation of the viral safety of biological products and/or the cells used to produce them. In research, only TEM has a resolution sufficiently high for discrimination between aggregated viral proteins and structured viral particles. Recent examples of different viral assembly models illustrate the value of TEM for improving our understanding of virus—cell interactions.
Structure–function analysis of plant aquaporin AtPIP2;1 gating by divalent cations and protons
Authors: Verdoucq Lionel , Grondin Alexandre , Maurel Christophe
Published: July 2008

Water channel proteins, AQPs (aquaporins), of the PIP (plasma membrane intrinsic protein) subfamily, provide a means for fine and quick adjustments of the plant water status. A molecular model for gating of PIPs by cytosolic protons (H+) and divalent cations was derived from the atomic structure of spinach SoPIP2;1 (Spinacia oleracea PIP2;1) in an open- and a closed-pore conformation. In the present study, we produced the Arabidopsis AtPIP2;1 (Arabidopsis thaliana PIP2;1) homologue in Pichia pastoris, either WT (wild-type) or mutations at residues supposedly involved in gating. Stopped-flow spectrophotometric measurements showed that, upon reconstitution in proteoliposomes, all forms function as water channels. The first functional evidence for a direct gating of PIPs by divalent (bivalent) cations was obtained. In particular, cadmium and manganese were identified, in addition to calcium (Ca2+) and H+ as potent inhibitors of WT AtPIP2;1. Our results further show that His199, the previously identified site for H+ sensing, but also N-terminal located Glu31, and to a lesser extent Asp28, are involved in both divalent-cation- and H+-mediated gating. In contrast, mutation of Arg124 rendered AtPIP2;1 largely insensitive to Ca2+ while remaining fully sensitive to H+. The role of these residues in binding divalent cations and/or stabilizing the open or closed pore conformations is discussed.
Growth of β2-microglobulin-related amyloid fibrils by non-esterified fatty acids at a neutral pH
Authors: Hasegawa Kazuhiro , Tsutsumi-Yasuhara Shinobu , Ookoshi Tadakazu , Ohhashi Yumiko , Kimura Hideki , Takahashi Naoki , Yoshida Haruyoshi , Miyazaki Ryoichi , Goto Yuji , Naiki Hironobu
Published: July 2008

Aβ2M (β2-microglobulin-related) amyloidosis is a frequent and serious complication in patients on long-term dialysis. Partial unfolding of β2-m (β2-microglobulin) may be essential to its assembly into Aβ2M amyloid fibrils in vivo. Although SDS around the critical micelle concentration induces partial unfolding of β2-m to an α-helix-containing aggregation-prone amyloidogenic conformer and subsequent amyloid fibril formation in vitro, the biological molecules with similar activity under near-physiological conditions are still unknown. The effect of various NEFAs (non-esterified fatty acids), which are representative anionic amphipathic compounds in the circulation, on the growth of Aβ2M amyloid fibrils at a neutral pH was examined using fluorescence spectroscopy with thioflavin T, CD spectroscopy, and electron microscopy. Physiologically relevant concentrations of laurate, myristate, oleate, linoleate, and mixtures of palmitate, stearate, oleate and linoleate, induced the growth of fibrils at a neutral pH by partially unfolding the compact structure of β2-m to an aggregation-prone amyloidogenic conformer. In the presence of human serum albumin, these NEFAs also induced the growth of fibrils when their concentrations exceeded the binding capacity of albumin, indicating that the unbound NEFAs rather than albumin-bound NEFAs induce the fibril growth reaction in vitro. These results suggest the involvement of NEFAs in the development of Aβ2M amyloidosis, and in the pathogenesis of Aβ2M amyloidosis.
Carotenoid oxygenases involved in plant branching catalyse a highly specific conserved apocarotenoid cleavage reaction
Authors: Alder Adrian , Holdermann Iris , Beyer Peter , Al-Babili Salim
Published: July 2008

Recent studies with the high-tillering mutants in rice (Oryza sativa), the max (more axillary growth) mutants in Arabidopsis thaliana and the rms (ramosus) mutants in pea (Pisum sativum) have indicated the presence of a novel plant hormone that inhibits branching in an auxin-dependent manner. The synthesis of this inhibitor is initiated by the two CCDs [carotenoid-cleaving (di)oxygenases] OsCCD7/OsCCD8b, MAX3/MAX4 and RMS5/RMS1 in rice, Arabidopsis and pea respectively. MAX3 and MAX4 are thought to catalyse the successive cleavage of a carotenoid substrate yielding an apocarotenoid that, possibly after further modification, inhibits the outgrowth of axillary buds. To elucidate the substrate specificity of OsCCD8b, MAX4 and RMS1, we investigated their activities in vitro using naturally accumulated carotenoids and synthetic apocarotenoid substrates, and in vivo using carotenoid-accumulating Escherichia coli strains. The results obtained suggest that these enzymes are highly specific, converting the C27 compounds β-apo-10′-carotenal and its alcohol into β-apo-13-carotenone in vitro. Our data suggest that the second cleavage step in the biosynthesis of the plant branching inhibitor is conserved in monocotyledonous and dicotyledonous species.
Non-normal Lanczos methods for quantum scattering
Authors: Khorasani Reza Rajaie , Dumont Randall S.
Published: July 2008

This article presents a new complex absorbing potential (CAP) block Lanczos method for computing scattering eigenfunctions and reaction probabilities. The method reduces the problem of computing energy eigenfunctions to solving two energy dependent systems of equations. An energy independent block Lanczos factorization casts the system into a block tridiagonal form, which can be solved very efficiently for all energies. We show that CAP-Lanczos methods exhibit instability due to the non-normality of CAP Hamiltonians and may break down for some systems. The instability is not due to loss of orthogonality but to non-normality of the Hamiltonian matrix. While use of a Woods–Saxon exponential CAP—as opposed to a polynomial CAP—reduced non-normality, it did not always ensure convergence. Our results indicate that the Arnoldi algorithm is more robust for non-normal systems and less prone to break down. An Arnoldi version of our method is applied to a nonadiabatic tunneling Hamiltonian with excellent results, while the Lanczos algorithm breaks down for this system.
A direct relativistic four-component multiconfiguration self-consistent-field method for molecules
Authors: Thyssen Jørn , Fleig Timo , Jensen Hans Jørgen Aa.
Published: July 2008

A new direct relativistic four-component Kramers-restricted multiconfiguration self-consistent-field (KR-MCSCF) code for molecules has been implemented. The program is based upon Kramers-paired spinors and a full implementation of the binary double groups (D2h* and subgroups). The underlying quaternion algebra for one-electron operators was extended to treat two-electron integrals and density matrices in an efficient and nonredundant way. The iterative procedure is direct with respect to both configurational and spinor variational parameters; this permits the use of large configuration expansions and many basis functions. The relativistic minimum-maximum principle is implemented in a second-order restricted-step optimization algorithm, which provides sharp and well-controlled convergence. This paper focuses on the necessary modifications of nonrelativistic MCSCF methodology to obtain a fully variational KR-MCSCF implementation. The general implementation also allows for the use of molecular integrals from a two-component relativistic Hamiltonian as, for example, the Douglas–Kroll–Hess variants. Several sample applications concern the determination of spectroscopic properties of heavy-element atoms and molecules, demonstrating the influence of spin-orbit coupling in MCSCF approaches to such systems and showing the potential of the new method.
The 2-naphthol-water2 cluster: Two competing types of hydrogen-bonding arrangements
Authors: Schemmel Dominik , Schütz Martin
Published: July 2008

The potential energy surfaces of the S0 and S1(π∗←π) states of the 2-naphthol(H2O)n, n∊{1,2} clusters were explored at the level of coupled cluster (CC2) response theory. In the electronic ground state two different types of hydrogen-bonding networks coexist for n=2, (i) a cyclic one [similar to those of the water trimer and phenol(H2O)2] where the hydroxy group of the aryl alcohol acts simultaneously as H donor for the first, and as H acceptor for the second water molecule, and (ii) a hydrogen-bonding arrangement where the aromatic π system is taking over the role as H acceptor. In the S1 state, on the other hand, the cyclic conformers are unstable. Consequently, the first group of cyclic ground state conformers gives rise to broad unstructured band shapes in the absorption spectrum, whereas the second group of conformers involving the aromatic π system gives rise to nicely structured band shapes. Based on these results the puzzling absorption spectrum of the n=2 cluster can properly be interpreted.
The effect of the order of the autocatalysis on the transverse stability of reaction fronts
Authors: Merkin J. H.
Published: July 2008

A linear stability analysis of planar reaction fronts to transverse perturbations is considered for a system based on an autocatalytic reaction of general order p. Dispersion curves, plots of the growth rate σ against a transverse wavenumber k, are obtained for a range of values of p and D, where D is the ratio of the diffusion coefficients of autocatalyst and substrate. A value D0 of D, dependent on p, is found at which σmax, the maximum value of σ in the unstable regime, is largest, with D0 increasing as p is increased. An asymptotic analysis for small wavenumbers is derived, which enables the region in the (p,D) parameter space for instability to be determined. An analysis for D small is undertaken, which leads to upper bounds on the wavenumber for a possible instability.