bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure and electrostatic property of cytoplasmic domain of ZntB transporter
Authors: Tan Kemin , Sather Alicia , Robertson Janice L. , Moy Shiu , Roux Benoît , Joachimiak Andrzej 
Published: August 2009

AbstractZntB is the distant homolog of CorA Mg2+ transporter within the metal ion transporter superfamily. It was early reported that the ZntB from Salmonella typhimurium facilitated efflux of Zn2+ and Cd2+, but not Mg2+. Here, we report the 1.90 Å crystal structure of the intracellular domain of ZntB from Vibrio parahemolyticus. The domain forms a funnel‐shaped homopentamer that is similar to the full‐length CorA from Thermatoga maritima, but differs from two previously reported dimeric structures of truncated CorA intracellular domains. However, no Zn2+ or Cd2+ binding sites were identified in the high‐resolution structure. Instead, 25 well‐defined Cl− ions were observed and some of these binding sites are highly conserved within the ZntB family. Continuum electrostatics calculations suggest that the central pore of the funnel is highly attractive for cations, especially divalents. The presence of the bound Cl− ions increases the stability of cations along the pore suggesting they could be important in enhancing cation transport.
Proligands with protease‐regulated binding activity identified from cell‐displayed prodomain libraries
Authors: Thomas Jerry M. , Daugherty Patrick S. 
Published: August 2009

AbstractA general method was developed for the discovery of protease‐activated binding ligands, or proligands, from combinatorial prodomain libraries displayed on the surface of E. coli. Peptide libraries of candidate prodomains were fused with a matrix metalloprotease‐2 substrate linker to a vascular endothelial growth factor‐binding peptide and sorted using a two‐stage flow cytometry screening procedure to isolate proligands that required protease treatment for binding activity. Prodomains that imparted protease‐mediated switching activity were identified after three sorting cycles using two unique library design strategies. The best performing proligand exhibited a 100‐fold improvement in apparent binding affinity after exposure to protease. This method may prove useful for developing therapeutic and diagnostic ligands with improved systemic targeting specificity.
Early antiallergic inflammatory effects ofRhus vernicifluastokes on human mast cells
Authors: Hong Myung Hee , Kim Jeong‐Hyun , Lee Sea Yun , Go Ho Yeon , Kim Ji Hye , Shin Yong‐Cheol , Kim Sung‐Hoon , Ko Seong‐Gyu 
Published: August 2009

AbstractRhus vernicifluaStokes (RVS) is a traditional medicine used in Korea, Japan and China to treat various diseases including catharsis, diaphoretic gastritis and stomach cancer. However, the effects of RVS on allergic inflammatory diseases are unknown to date. This study showed the antiallergic inflammatory effects of RVS on human mast cells (HMC‐1) which were stimulated by phorbol myristate acetate (PMA) and calcium ionophore A23187. RVS inhibited the expressions of TNF‐α, IL‐6 and IL‐8 that were stimulated by treatment with both PMA and A23187. Among the mitogen‐activated protein kinases (MAPKs), extracts of RVS suppressed the phosphorylation of ERK and p38, whereas RVS increased the phosphorylation of JNK in HMC‐1. Consistent with the regulation of MAPKs, it was found that RVS inhibited the nuclear translocation of nuclear factor (NF)‐κB via inhibition of the phosphorylation of IκB‐α, which are important processes in controlling inflammatory responses. Taken together, these results suggest that RVS modulates the expressions of signal molecules related to allergic inflammatory responses mainly through the ERK signaling pathway, suggesting that RVS could be used as a treatment for mast cell‐derived allergic inflammatory diseases. Copyright © 2009 John Wiley & Sons, Ltd.
Antiproliferative effect of benzophenones and their influence on cathepsin activity
Authors: Murata Ramiro Mendonça , Yatsuda Regiane , dos Santos Marcelo Henrique , Kohn Luciana K. , Martins Felipe Terra , Nagem Tanus Jorge , Alencar Severino Matias , de Carvalho João Ernesto , Rosalen Pedro Luiz 
Published: August 2009

AbstractThe antiproliferative activity of two prenylated benzophenones isolated from Rheedia brasiliensis, the triprenylated garciniaphenone and the tetraprenylated benzophenone 7‐epiclusianone, was investigated against human cancer cell lines. The antiproliferative activity on melanoma (UACC‐62), breast (MCF‐7), drug‐resistant breast (NCI‐ADR), lung/non‐small cells (NCI460), ovarian (OVCAR 03), prostate (PC03), kidney (786‐0), lung (NCI‐460) and tongue (CRL‐1624 and CRL‐1623) cancer cells was determined using spectrophotometric quantification of the cellular protein content. The effect of these benzophenones on the activity of cathepsins B and G was also investigated. Garciniaphenone displayed cytostatic activity in all cell lines, whereas 7‐epiclusianone showed a dose‐dependent cytotoxic effect. The IC50 values for cell proliferation revealed that 7‐epiclusianone is more active than garciniaphenone against most of the cell lines. Furthermore, the antiproliferative effects demonstrated by garciniaphenone and 7‐epiclusianone were related to their cathepsin inhibiting properties. In conclusion, 7‐epiclusianone is a promising naturally occurring agent which displays multiple inhibitory effects which may be working in concert to inhibit cancer cell proliferation in vitro. The putative pathway by which 7‐epiclusianone affects cancer cell development may involve cathepsin inhibition. Copyright © 2009 John Wiley & Sons, Ltd.
Protective effect of Astragalus polysaccharides on ATP binding cassette transporter A1 in THP‐1 derived foam cells exposed to tumor necrosis factor‐alpha
Authors: Wang Yan‐Fu , Yang Xiao‐Fang , Cheng Bei , Mei Chun‐Li , Li Qing‐Xian , Xiao Hua , Zeng Qiu‐Tang , Liao Yu‐Hua , Liu Kun 
Published: August 2009

AbstractAstragalus polysaccharide (APS), the main extract from the traditional Chinese medicinal herb Astragalus membranaceus, has been reported to benefit the treatment of immune‐inflammatory diseases and metabolic disorders. In atherosclerotic plaques, proinflammatory cytokines exert adverse effects on lipids thereby aggravating atherosclerosis. Recent evidence shows that tumor necrosis factor‐alpha (TNF‐α) can down‐regulate the expression of ATP‐binding cassette transporter A1 (ABCA1), which plays a vital role in reverse cholesterol transport and determines the process of atherosclerosis. In the present study, the effects of APS on ABCA1 expression, cholesterol effluent rate and total cholesterol content of THP‐1 derived foam cells exposed to TNF‐α were investigated. Compared with the foam cells exposed to TNF‐α, ABCA1 expression was promoted in the presence of APS. Consequently the cholesterol effluent rate increased and the total cholesterol content decreased significantly. TNF‐α could enhance the activity of nuclear factor‐kappa B (NF‐κB) in the foam cells. This effect could be attenuated by APS. These findings suggest that APS could protect ABCA1 against the lesion of TNF‐α in THP‐1 derived foam cells, which may contribute to its antiatherosclerotic properties. Copyright © 2009 John Wiley & Sons, Ltd.
Protective effects of steroids from Allium chinense against H2O2‐induced oxidative stress in rat cardiac H9C2 cells
Authors: Ren Gang , Qiao Hong Xiang , Yang Jun , Zhou Chang Xin 
Published: August 2009

AbstractAllium chinense, a traditional herbal medicine, has been used for the treatment of cardiovascular diseases for hundreds of years. In this study, A. chinense steroids (ACSs) including three steroidal glycosides and their parent aglycones were isolated from the bulbs of A. chinense. For the first time, their cardioprotective effects were evaluated in cultured rat cardiac H9C2 cells by pretreatment with ACSs for 24 h before exposure to 0.2 mm H2O2. The results showed the cell viability decreased markedly when H9C2 cells were incubated with 0.2 mm H2O2 alone for 2 h, while the cell lipid peroxidation (estimated by the excessive production of nitric oxide and malondialdehyde) and intracellular free calcium concentration ([Ca2+]i) increased significantly. The addition of 20 μm (below the toxic concentration) of ACSs notably attenuated the cellular injury induced by H2O2. The effects of ACSs in our experiments were similar to those of nimodipine, a clinically applied calcium channel blocker. Preliminary analysis of the structure–activity relationship indicated that ACSs with a spirostane‐type skeleton exhibited stronger protection than that with a furostane‐type skeleton, and glycosylation of the steroids could substantially lower the protective activities. The above results suggested the protective effects of steroids originated from A. chinense on the oxidative injury of H9C2 cells and ACSs may have potential for preventing cardiac injuries induced by oxidative stress. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of crocin on the morphine‐induced antinociception in the formalin test in rats
Authors: Tamaddonfard Esmaeal , Hamzeh‐Gooshchi Nasrin 
Published: August 2009

AbstractIn this study, the effects of intraperitoneal (i.p.) injection of crocin in the absence and presence of subcutaneous (s.c.) injections of morphine and naloxone were investigated on the formalin test in rats. The formalin test was induced by intra‐plantar (i.pl.) injection of formalin (50 μL, 1%), and the time spent licking and biting of the injected paw was measured for 1 h. Formalin induced a marked biphasic (first phase: 0–5 min and second phase: 15–45 min) pain response. Morphine (1 mg/kg, s.c.) significantly (p< 0.05) suppressed both phases of pain. Naloxone (2 mg/kg, s.c.) alone did not change the intensity of pain, but pretreatment with naloxone (2 mg/kg) significantly (p< 0.05) prevented morphine (1 mg/kg)‐induced antinociception. Crocin at doses of 50, 100 and 200 mg/kg significantly (p< 0.05) attenuated pain. Crocin (100 mg/kg, i.p.) significantly (p< 0.05) increased the morphine (1 mg/kg, s.c.)‐induced antinociception. Naloxone (2 mg/kg) did not reverse the suppressive effect of crocin (100 mg/kg) on pain. Crocin at a dose of 400 mg/kg significantly (p< 0.05) suppressed locomotor activities. These findings indicate that morphine through a naloxone‐sensitive mechanism produced analgesia. Crocin produced a dose‐dependent antinociceptive effect. In addition, crocin increased morphine‐induced antinociception, but naloxone did not change the antinociceptive effect of crocin. Copyright © 2009 John Wiley & Sons, Ltd.
Simultaneous state estimation and attenuation correction for thunderstorms with radar data using an ensemble Kalman filter: tests with simulated data
Authors: Xue Ming , Tong Mingjing , Zhang Guifu 
Published: August 2009

AbstractA new approach to dealing with attenuated radar reflectivity data in the data assimilation process is proposed and tested with simulated data using the ensemble square‐root Kalman filter. This approach differs from the traditional method where attenuation is corrected in observation space first before observations are assimilated into numerical models. We build attenuation correction into the data assimilation system by calculating the expected attenuation within the forward observation operators using the estimated atmospheric state. Such a procedure does not require prior assumption about the types of hydrometeor species along the radar beams, and allows us to take advantage of knowledge about the hydrometeors obtained through data assimilation and state estimation. Being based on optimal estimation theory, error and uncertainty information on the observations and prior estimate can be effectively utilized, and additional observed parameters, such as those from polarimetric radar, can potentially be incorporated into the system. Tests with simulated reflectivity data of an X‐band 3 cm wavelength radar for a supercell storm show that the attenuation correction procedure is very effective—the analyses obtained using attenuated data are almost as good as those obtained using unattenuated data. The procedure is also robust in the presence of moderate dropsize‐distribution‐related observation operator error and when systematic radar calibration error exists. The analysis errors are very large if no attenuation correction is applied. The effect of attenuation and its correction when radial velocity data are also assimilated is discussed as well. In general, attenuation correction is equally important when quality radial velocity data are also assimilated. Copyright © 2009 Royal Meteorological Society
The 11 August 2006 squall‐line system as observed from MIT Doppler radar during the AMMA SOP
Authors: Chong Michel 
Published: August 2009

AbstractOn the evening of 9 August 2006, a mesoscale convective system (MCS) having a north‐south oriented squall‐line organization formed over the border between Chad and Nigeria. It propagated westward, intensified over Nigeria on 10 August, and reached Niamey (Niger) at 0320 UTC on 11 August. Its passage over Niamey was accompanied by dust lifting and was well tracked by the Massachusetts Institute of Technology (MIT) Doppler radar. The three‐dimensional structure of the airflow and precipitation pattern is investigated from regular radar volume scans performed every ten minutes between 0200 and 0321 UTC. The 3D wind components are deduced from the multiple‐Doppler synthesis and continuity adjustment technique (MUSCAT) applied to a set of three volume scans obtained over a time period of one hour, which are equivalent to a three‐radar observation of the squall line when considering a reference frame moving with the system and the hypothesis of a stationary field.Results of the wind synthesis reveal several features commonly observed in tropical squall lines, such as the deep convective cells in front of the system, fed by the monsoon air and extending up to 15 km altitude, and the well‐marked stratiform rain region at the rear, associated with mesoscale vertical motions. Forward and trailing anvils are clearly identified as resulting from the outflow of air reaching the tropopause and transported to this level by the sloping convective updraughts occurring in a sheared environment. In the northern part, a deeper and stronger front‐to‐rear flow at mid‐levels is found to contribute to the rearward deflection of the leading line and to promote a broader (over 300 km) stratiform cloud region. Eddy vertical transports of the cross‐line momentum mainly accounts for the mid‐level flow acceleration due to a momentum redistribution from low to higher levels. The height distribution of hydrometeors and their associated production terms derived from a one‐dimensional microphysical retrieval model indicate the distinct roles of the convective and stratiform regions in the formation of graupel and rain, and the respective contributions of cold (riming) and warm (coalescence, melting) processes. Cooling from melting, and heating/cooling from condensation/evaporation processes yield a net decrease and increase of the potential temperature at low and mid‐to‐upper levels, respectively, with respect to an environmental thermodynamic profile taken three hours ahead of the analysis. Finally, the upper‐level rearward flow could convey the non‐negligible proportion of ice particles farther from the leading deep convection to the trailing stratiform region, thereby favouring the extent of this region. Copyright © 2009 Royal Meteorological Society
A fragmentation study of dihydroquercetin using triple quadrupole mass spectrometry and its application for identification of dihydroflavonols in Citrus juices
Authors: Abad‐García Beatriz , Garmón‐Lobato Sergio , Berrueta Luis A. , Gallo Blanca , Vicente Francisca 
Published: August 2009

AbstractA mass spectrometric method using electrospray ionization with triple quadrupole and quadrupole time‐of‐flight hybrid (Q‐Tof) mass spectrometry has been applied to the structural characterization of dihydroflavonols. This family of compounds has been studied by liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the first time in this work. A comprehensive study of the product ion MS spectra of the [M+H]+ ion of a commercially available standard has been performed. The most useful fragmentations in terms of structural identification are those that involve cleavage of the C‐ring, resulting in diagnostic ions of dihydroflavonol family: 1,3A, 1,2B, 1,2B‐CO, 0,2A, 0,2A‐H2O, 0,2A‐CO, and 0,2A‐H2O‐CO, that allow the characterization of the substituents in the A‐ and B‐rings. In addition to those ions, other product ions due to losses of H2O and CO molecules from the Y ion were observed. Their fragmentation mechanisms and ion structures have been proposed. The established fragmentation patterns have been used to successfully identity three dihydroflavonols found in tangerine juices for the first time. Copyright © 2009 John Wiley & Sons, Ltd.
Mass peak shape improvement of a quadrupole mass filter when operating with a rectangular wave power supply
Authors: Luo Chan , Jiang Dan , Ding Chuan‐Fan , Konenkov Nikolai V. 
Published: August 2009

AbstractNumeric experiments were performed to study the first and second stability regions and find the optimal configurations of a quadrupole mass filter constructed of circular quadrupole rods with a rectangular wave power supply. The ion transmission contours were calculated using ion trajectory simulations. For the first stability region, the optimal rod set configuration and the ratio r/r0 is 1.110–1.115; for the second stability region, it is 1.128–1.130. Low‐frequency direct current (DC) modulation with the parameters of m = 0.04–0.16 and ν = ω/Ω = 1/8–1/14 improves the mass peak shape of the circular rod quadrupole mass filter at the optimal r/r0 ratio of 1.130. The amplitude modulation does not improve mass peak shape. Copyright © 2009 John Wiley & Sons, Ltd.
A numerical evaluation of chamber methodologies used in measuring the δ13C of soil respiration
Authors: Nickerson Nick , Risk Dave 
Published: August 2009

AbstractMeasurement of the δ13C value of soil‐respired CO2 (δr) has become a commonplace method through which ecosystem function and C dynamics can be better understood. Despite its proven utility there is currently no consensus on the most robust method with which to measure δr. Static and dynamic chamber systems are both commonly used for this purpose; however, the literature on these methods provides evidence suggesting that measurements of δr made with these chamber systems are neither repeatable (self‐consistent) nor comparable across methodologies. Here we use a three‐dimensional (3‐D) numerical soil‐atmosphere‐chamber model to test these chamber systems in a ‘surrogate reality’. Our simulations show that each chamber methodology is inherently biased and that no chamber methodology can accurately predict the true δr signature under field conditions. If researchers intend to use δr to study in situ ecosystem processes, the issues with these chamber systems need to be corrected either by using diffusive theory or by designing a new, unbiased δr measurement system. Copyright © 2009 John Wiley & Sons, Ltd.
13C/12C isotope labeling to study carbon partitioning and dark respiration in cereals subjected to water stress
Authors: Aranjuelo Iker , Cabrera‐Bosquet Llorenç , Mottaleb Shady A. , Araus José L. , Nogués Salvador 
Published: August 2009

AbstractDespite the relevance of carbon (C) loss through respiration processes (with its consequent effect on the lower C availability for grain filling), little attention has been given to this topic. Literature data concerning the role of respiration in cereals are scarce and these have been produced using indirect methods based on gas‐exchange estimations. We have developed a new method based on the capture of respired CO2 samples and their analysis by gas chromatography‐combustion‐isotope ratio mass spectrometry (GC‐C‐IRMS). In order to analyse the main processes involved in the C balance during grain filling (photosynthesis, respiration, allocation and partitioning) the ambient isotopic 13C/12C composition (δ13C) of the growth chamber was modified during this period (δ13C ca. −12.8 ± 0.3‰ to ca. −20.0 ± 0.2‰). The physiological performance, together with the C allocation on total organic matter (TOM) and respiration of wheat (Triticum aestivum L., var. Califa sur) and two hybrids, tritordeum (X Tritordeum Asch. & Graebn line HT 621) and triticale (X Triticosecale Wittmack var. Imperioso), were compared during post‐anthesis water stress. In spite of the larger ear DM/total ratio, especially under drought conditions, the grain filling of triticale and wheat was mainly carried out with pre‐anthesis C, while the majority of C assimilated during post‐anthesis was invested in respiration processes. In the case of wheat and tritordeum, the C balance data suggested a reallocation during grain filling of photoassimilates stored prior to anthesis from shoot to ear. Furthermore, the lower percentage of labeled C on respired CO2 of droughted tritordeum plants, together with the lower plant biomass, explained the fact that those plants had more C available for grain filling. Copyright © 2009 John Wiley & Sons, Ltd.
Rapid and nondestructive analysis of phthalic acid esters in toys made of poly(vinyl chloride) by direct analysis in real time single‐quadrupole mass spectrometry
Authors: Rothenbacher Thorsten , Schwack Wolfgang 
Published: August 2009

AbstractIn the European Community, selected phthalic acid esters (PAE) are restricted in their use for the manufacture of toys and childcare articles to a content of 0.1% by weight. As PAE are mainly used as plasticisers for poly(vinyl chloride) (PVC), a rapid screening method for PVC samples with direct analysis in real time ionisation and single‐quadrupole mass spectrometry (DART‐MS) was developed. Using the ions for the protonated molecules, a limit of detection (LOD) of 0.05% was obtained for benzyl butyl phthalate, bis(2‐ethylhexyl) phthalate and diisononyl phthalate, while for dibutyl phthalate, di‐n‐octyl phthalate and diisodecyl phthalate the LOD was 0.1%. Validation of identification by the presence of ammonium adducts and characteristic fragment ions was possible to a content of ≥1% for all PAE, except for benzyl butyl phthalate (≥5%). Based on the fragment ions, bis(2‐ethylhexyl) phthalate could clearly be distinguished from di‐n‐octyl phthalate, if the concentrations were ≥5% and ≥1% at measured DART helium temperatures of 130 and 310°C, respectively. The complete analysis of one sample only took about 8 min. At the generally used gas temperature of 130°C, most toy and childcare samples did not sustain damage if their shape fitted into the DART source. Copyright © 2009 John Wiley & Sons, Ltd.
Delay‐dependent robust control for singular discrete‐time Markovian jump systems with time‐varying delay
Authors: Zhou Wuneng , Lu Hongqian , Duan Chunmei , Li Minghao 
Published: August 2009

AbstractThe problem of delay‐dependent robust stabilization for uncertain singular discrete‐time systems with Markovian jumping parameters and time‐varying delay is investigated. In terms of free‐weighting‐matrix approach and linear matrix inequalities, a delay‐dependent condition is presented to ensure a singular discrete‐time system to be regular, causal and stochastically stable based on which the stability analysis and robust stabilization problem are studied. An explicit expression for the desired state‐feedback controller is also given. Some numerical examples are provided to demonstrate the effectiveness of the proposed approach. Copyright © 2009 John Wiley & Sons, Ltd.