bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of temperature, solvent, Lewis acid and additives on the polymerization of tert‐butyl vinyl ether using Lewis acid‐induced N‐methyleneamines as cationic initiators
Authors: Leasure Joshua G , Brinkman Chelsea E , Tillman Eric S , Monk Ian W , Cohen Nicole A
Published: December 2009

N‐Methyleneamines, formed by treating 1,3,5‐trimethylhexahydro‐1,3,5‐triazines with Lewis acids, have been shown to be capable initiators in the cationic polymerization of tert‐butyl vinyl ether, yielding polymers with amine functionality at the chain ends. Previous work was limited to titanium(IV) chloride (TiCl4) as the Lewis acid in dichloromethane solvent at 0 °C (with resulting polymers possessing relatively broad polydispersity index (PDI) values near 2), while this contribution details the effect of reaction parameters on the polymeric products; specifically, the role of temperature, solvent, Lewis acid and additives. Ultimately, performing the polymerization at −78 °C in dichloromethane with TiCl4 as the Lewis acid and tetra‐n‐butylammonium chloride (nBu4NCl) as the additive afforded the best control over the system, with polymers formed possessing low PDI values (<1.2). Dramatic changes in number‐average molecular weight and PDI were observed in polymers formed by initiating systems of Lewis acid‐induced N‐methyleneamines, with temperature, solvent, Lewis acid and additives all playing a role. By varying single parameters, optimization of the system was achieved. Copyright © 2009 Society of Chemical Industry
Inactivation of Bacteria in an Aqueous Environment by a Direct‐Current, Cold‐Atmospheric‐Pressure Air Plasma Microjet
Authors: Liu Fuxiang , Sun Peng , Bai Na , Tian Ye , Zhou Haixia , Wei Shicheng , Zhou Yanheng , Zhang Jue , Zhu Weidong , Becker Kurt , Fang Jing
Published: December 2009

A direct‐current, cold‐atmospheric‐pressure air plasma microjet (PMJ) sustained in a quasi‐steady gas cavity in a liquid medium is used to inactivate Staphylococcus aureus (S. aureus) suspended in the liquid. The temperature and the pH value of the liquid change to steady‐state values of about 40 °C and 3.0–4.5, respectively, after 10 min of plasma treatment. The decrease in the pH is attributed to the reaction of NOx produced in the air plasma with water at the gas–liquid interface. The concentrations of NO and NO are measured to be 37 mg · L−1 and 21 mg · L−1, respectively, after a 20 min of plasma treatment. Effective inactivation of S. aureus is found to start after the pH values decreases to about 4.5. This is attributed to the high oxidizing potential of the perhydroxyl radical (HOO•) on the fatty acid in the cell membranes of the microorganisms in the liquid.

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Crystal Shape Characterisation of Dry Samples using Microscopic and Dynamic Image Analysis
Authors: Patchigolla Kumar , Wilkinson Derek
Published: December 2009

A standard method to determine particle shape and size is by image analysis. This paper addresses microscopic image analysis (semi‐automated) investigations of two different organic crystalline chemicals generated by batch cooling crystallisation. The results generated from microscopic image analysis were compared with data obtained by dynamic image analysis (automated) because very few contributions are available in the open literature. The chemical systems were polymorphic L‐glutamic acid which crystallises into α (prismatic) or β (needle) form and the non‐polymorphic mono sodium glutamate which crystallises into needles. The images from these techniques were processed to generate information on crystal shape and size. It has been observed that shape effects can distort the size obtained in size characterization studies.

In this study, comparisons were made of processing time, number of crystals and accuracy between microscopic and dynamic image analysis. For representative microscopic image analysis, 5000 crystals were analysed in an average of eight hours while several hundred thousand crystals were processed using dynamic image analysis within 15 minutes. Using the parameters D10, D50, D90, span and aspect ratio for statistical comparison, it was found that the results obtained for D50 by the two techniques were comparable and in accordance with other measurements (laser diffraction spectroscopy and ultrasonic attenuation spectroscopy) even though these non‐spherical particles had different orientations during measurement by the two methods. However, substantial differences in span of the distribution and aspect ratio were returned by the two techniques.
Serologically verified human bocavirus pneumonia in children
Authors: Don Massimiliano , Söderlund‐Venermo Maria , Valent Francesca , Lahtinen Anne , Hedman Lea , Canciani Mario , Hedman Klaus , Korppi Matti
Published: December 2009

Working Hypothesis

Human bocavirus (HBoV) is a newly identified parvovirus frequently found in children suffering from acute respiratory and intestinal infections. The aim of the present study was to evaluate, by using a newly developed antibody assay, the role of HBoV in pediatric community‐acquired pneumonia (CAP) and the seropositivity rate to HBoV in a prospective study in North‐Italian children.

Materials/Patients and Methods

During a 15‐month study period, 124 children were admitted due to presumptive pneumonia, and in 101 of them, pneumonia was radiologically confirmed. The etiology of CAP was studied by antibody assays to 16 microbes, including the newly developed enzyme immunoassay for HBoV.

Results

Serological evidence of acute HBoV infection was found in 12 (12%) children, being single in 7 and mixed in 5 cases (4 with other viruses and 3 with bacteria). IgM was positive in 11 cases. A diagnostic rise in IgG antibodies between paired sera was observed in six cases. HBoV was the second most common virus next to respiratory syncytial virus (17%). The seropositivity rate to HBoV increased with age, reaching nearly 100% before school age.

Conclusions

The present results show that HBoV is able to induce significant antibody responses and suggest that HBoV may be a fairly common cause of pneumonia in children. Seroconversion to HBoV in most children takes place in early childhood. Pediatr Pulmonol. 2010; 45:120–126. © 2010 Wiley‐Liss, Inc.
Prevent major failures and accidents with well‐trained and empowered operators
Authors: Idrees Muhammad , Aslam S.
Published: December 2009

This article shares Engro's experience at its ammonia plant involving the prevention of major failures of the synthesis gas compressor turbine by taking prompt action to shutdown the compressor. Engro's strategy of providing operations training to enable and empower its people to make the right decisions at right time is the major learning of this article, whereby a manual shutdown before the automatic instrumentation trip of the machine was initiated. This article also describes the techniques used by the operations team to train and empower their people. Despite a plant outage of more than 10 days to replace the rotor, we believe the manual shutdown averted a more disastrous situation. Continuing to run the turbine may have resulted in a safety incident or an even longer plant shutdown for significant repairs. A well‐trained and empowered operator is always helpful by making prompt decisions to shut down equipment, rather than relying solely on instrumentation to protect equipment. The following is a discussion of the training program which enables and empowers the operator to make correct decisions and take the correct action at the right time. © 2009 American Institute of Chemical Engineers Process Saf Prog, 2010
Estimation of the flammability zone boundaries for flammable gases
Authors: Hansen Travis J. , Crowl Daniel A.
Published: December 2009

For flammable gases and liquids in air, the upper and lower flammable limits are adequate to define the flammability. However, for either nitrogen or oxygen enriched mixtures the flammability is expressed more generally as a boundary in a flammable zone.

This work presents equations to model the boundary of the flammable zone, with an emphasis on developing simple, direct algebraic equations. Separate equations are developed for the upper and lower boundaries to estimate the flammable zone. Two methods are presented to predict the upper and lower flammability zone boundaries: a simple thermodynamic model and an empirical model. The flammability zone boundary models are also applied to predict the limiting oxygen concentration (LOC) and the upper and lower oxygen limits (LOL).

The simple thermodynamic model is based on the adiabatic temperature change and assumes a simple reaction scheme and constant physical properties. This method approximates the boundaries as linear equations. This method uses the upper flammability and lower flammability limits (LFL) to calculate two adiabatic flame temperatures and attempts to account for the changes in the reactions along the upper flammability zone boundary. The empirical method approximates the boundaries with linear equations that are functions of the upper or LFL.

Comparison of the models to experimental data shows that the empirical model works best for estimating the flammability zone boundaries. This model also estimates the limiting oxygen concentration, upper oxygen limit (UOL), and the LOL quite well. The regression coefficient values for the limiting oxygen concentration, UOL, and LOL are 0.672, 0.968, and 0.959, respectively. This is better than the fit of the yLOC = zyLFL method for the LOC, in which the regression coefficient's value is 0.416. © 2009 American Institute of Chemical Engineers Process Saf Prog, 2010
Inheritance of resistance to a new non‐steroidal ecdysone agonist, fufenozide, in the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)
Authors: Sun Jingyan , Liang Pei , Gao Xiwu
Published: December 2009

BACKGROUND: The diamondback moth (DBM), Plutella xylostella (L.), is a cosmopolitan pest of cruciferous crops. Fufenozide, a novel non‐steroidal ecdysone agonist, exhibits good efficacy and plays an increasingly important role in the control of Lepidopterous pests in China. A laboratory strain of DBM was selected for resistance to fufenozide, and the genetic basis of resistance was studied.

RESULTS: The resistant strain, selected under laboratory conditions, exhibited a higher level of resistance to fufenozide (302.8‐fold based on LC50s) than the laboratory susceptible strain. Mortality data from the testing of F1 progeny of reciprocal crosses of resistant and susceptible DBM indicated that resistance was autosomal and incompletely recessive with a degree of dominance of −0.664. Chi‐square analysis from responses of a backcross of crossed F1 progeny and the resistant strain and F2 progeny were highly significant, suggesting that the resistance was probably controlled by more than one gene. The estimated realised heritability (h2) of fufenozide resistance was 0.08, indicating that diamondback moth may have a lower chance of developing resistance to fufenozide than other kinds of insecticide.

CONCLUSION: The resistance of DBM to fufenozide might be autosomal and incompletely recessive, and the resistance is probably controlled by more than one gene. These results provide the basic information for pest management programmes. Copyright © 2009 Society of Chemical Industry
Diversifying European agglomerations: evidence of urban population trends for the 21st century
Authors: Kabisch Nadja , Haase Dagmar
Published: December 2009

The beginning of the 21st century marks the first time in history that more than half of the world's population lives in urban areas. In Europe, more than 70% of the population lives in urban areas today. This number is likely to increase to 84% by 2050. However, a shift from growth to decline of urban population is already present for a growing number of cities. The paper examines urban population trends for 158 European agglomerations and assesses the dynamics behind one particular development of growth or decline. Using data from 1991 to 2004, we present statistical evidence of diversifying population trajectories for core cities and fringe areas. The quantitative results are contrasted with the widespread accepted cyclical urbanisation model that has been expounded as a theoretical approach to describe previous and future stages of European urban development. The structural approach of the model is discussed because we believe that such concepts do not reflect the dynamics of present urban development in Europe. The paper argues that the urban agglomerations studied do not show a single evolutionary stage of urban development. Rather, we found a coexistence of intensifying suburbanisation and developing reurbanisation, which is mainly driven by younger households. Copyright © 2009 John Wiley & Sons, Ltd.
Emergent spaces of reurbanisation: exploring the demographic dimension of inner‐city residential change in a European setting
Authors: Haase Annegret , Kabisch Sigrun , Steinführer Annett , Bouzarovski Stefan , Hall Ray , Ogden Philip
Published: December 2009

European inner city areas are increasingly regaining their residential attractiveness after years of decline. Although the demographic dimensions of such residential shifts are gradually being acknowledged by urban scholars, they still remain under‐researched, especially with regard to the role of household‐driven processes in the stabilisation of inner‐city neighbourhoods and the reshaping of residential perceptions, wants and needs.

Given this background, our paper looks at the underlying dynamics of reurbanisation processes in different European cities. Reurbanisation is understood as a process of populating and diversifying the inner city with a variety of residential groups of different ages and socio‐economic backgrounds. We discuss why and how reurbanisation is changing inner‐city districts, while arguing that the demographic or household‐related view can lead to an improved understanding of current urban change. We demonstrate that – in contrast to a prevailing tendency to understand reurbanisation as an expression of a ‘back‐to‐the‐city’ movement – it relates more to city‐mindedness as a housing preference rather than to the actual return of suburbanites to the city. A typology of reurbanisation processes (distinguishing between different driving forces, and respective impacts on inner‐city area and housing markets) is provided, and the role of both social and demographic factors discussed. In particular, the paper examines overlaps and differences between reurbanisation and the concept of gentrification, arguing that, although they are partly driven by similar dynamics, the two processes are, in a qualitative sense, distinctive. Copyright © 2009 John Wiley & Sons, Ltd.
Eutigoside C attenuates radiation‐induced crypt injury in the mouse intestine
Authors: Moon Changjong , Ahn Kyuyoung , Kim Jihoon , Kim Jeongtae , Kim Sung‐Ho , Oh Tae Heon , Lee Nam Ho , Jee Youngheun , Hyun Jin Won , Park Jae Woo , Shin Taekyun
Published: December 2009

On Jeju Island, South Korea, the leaves of Eurya emarginata have been traditionally used to treat ulcers or as a diuretic. Eutigoside C isolated from the leaves has been reported to have in vitro anti‐inflammatory effects. We evaluated the radioprotective effects of eutigoside C on jejunal cell apoptosis and crypt survival in mice subjected to gamma irradiation. In addition, the ability of eutigoside C to protect against radiation‐induced oxidative stress was examined by evaluating the activities of superoxide dismutase (SOD) and catalase (CAT) in radiation‐induced hepatic injury. Eutigoside C was administered intraperitoneally at 48, 12, and 1 h before irradiation. The administration of eutigoside C (10, 50, or 100 mg/kg body weight) before irradiation protected the intestinal crypts from radiation‐induced apoptosis (p < 0.05), and attenuated radiation‐induced decrease of villous height (p < 0.05). Pretreating mice prior to irradiation with eutigoside C (100 mg/kg) significantly improved the survival of the jejunal crypt (p < 0.01). The dose reduction factor was 1.09 at 3.5 days after irradiation. Treatment of eutigoside C prior to irradiation significantly protected SOD and CAT activities in radiation‐induced hepatic injury (p < 0.05). These results suggest that eutigoside C is a useful radioprotector capable of defending intestinal progenitor cells against indirect depletion, such as oxidative stress and inflammatory response caused by gamma irradiation. Copyright © 2009 John Wiley & Sons, Ltd.
Antitumor activities of dammarane triterpene saponins from Bacopa monniera
Authors: Peng Ling , Zhou Yun , Kong De Yun , Zhang Wei Dong
Published: December 2009

Bioassay‐guided methods were used to test the antitumor activity of methanol extract of the whole plant of Bacopa monniera (L.) Wettst. and four different fractions (petroleum ether, CHCl3, EtOAc, and n‐BuOH fractions) of the methanol extract. Among the five crude samples, n‐BuOH fraction was noted to have the highest antitumor activity. The dammarane triterpene saponins isolated from n‐BuOH fraction, bacopaside É (1) and bacopaside VII (3), had potential antitumor effect. 1 and 3 showed cytotoxicity of all the tested human tumor cell lines MDA‐MB‐231, SHG‐44, HCT‐8, A‐549 and PC‐3M in MTT assay in vitro, and showed 90.52 % and 84.13 % inhibition in mouse implanted with sarcoma S180 in vivo at the concentration of 50 μmol/kg, respectively. The remaining two compounds, bacopaside II (2) and bacopasaponin C (4) were found to be much less potent compared with 1 and 3. 1 and 3 significantly inhibited human breast cancer cell line MDA‐MB‐231 adhesion, migration and Matrigel invasion in vitro at the concentration of 50 μmol/L. Since no antitumor activities about the monomers from Bacopa monniera (L.) Wettst. have been reported, these results indicate that the mechanism of action of 1 and 3 needs further study. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of Astragalus membranaceus and Angelica sinensis combined with Enalapril in rats with obstructive uropathy
Authors: Wojcikowski Ken , Wohlmuth Hans , Johnson David W. , Gobe Glenda
Published: December 2009

ACE inhibitors (ACEi) reduce renal tubulointerstitial fibrosis but are not completely effective. Combined extract of Astragalus membranaceus and Angelica sinensis (A&A) is a traditional antifibrotic agent in China. The present investigation aimed to determine whether an ACEi (Enalapril) and A&A together have a better antifibrotic effect in unilateral ureteral obstruction (UUO) than monotherapy with either agent. Male Sprague‐Dawley rats (N = 4 per group) had either sham operation or UUO alone, with A&A (combined aqueous and ethanol extract equivalent to 2.1 g dried herbs), with Enalapril (in drinking water at 200 mg/mL) or with both treatments. Kidney and liver were collected for protein extraction or fixed for histologic stains, immunohistochemistry (IHC), microscopy. Enalapril or A&A individually were antifibrotic. Transforming growth factor‐β1, fibroblast activation, collagen deposition, macrophage accumulation and tubular cell apoptosis were all decreased. The combination of the two drugs was significantly more effective than Enalapril alone in reducing tumor necrosis factor‐α, collagen accumulation, activation of fibroblasts, and tubular cell apoptosis. In conclusion, Enalapril with A&A significantly decreased tubulointerstitial fibrosis to a greater extent than treatment with Enalapril alone. Further studies focusing on the isolation of the active constituents of A&A and the clinical application of the combination of ACEi plus A&A are warranted to determine the value of this treatment in humans. Copyright © 2009 John Wiley & Sons, Ltd.
Mangiferin prevents diabetic nephropathy progression in streptozotocin‐induced diabetic rats
Authors: Li Xuan , Cui Xiaobing , Sun Xiaoyu , Li Xiaodong , Zhu Quan , Li Wei
Published: December 2009

Diabetic nephropathy is one of the most severe diabetic microangiopathies and accounting for approximately one‐third of all cases of end‐stage renal disease. In the present study, we investigated the effect of mangiferin, a polyphenol from Anemarrhena asphodeloides Bge. or Mangifera indica L., on diabetic nephropathy and the possible mechanisms by using a developed diabetic nephropathy rat model and cultured rat mesangial cells. Serum‐advanced glycation end‐products level, malonaldehyde level, sorbitol concentration of red blood cell, 24 h albuminuria excretion were significantly decreased, whereas activity of serum superoxide dismutase and glutathione peroxidase and creatinine clearance rate were increased by mangiferin. Blood glucose level remained unaffected. Mangiferin significantly inhibited glomerular extracellular matrix expansion and accumulation and transforming growth factor‐beta 1 overexpression in glomeruli of diabetic nephropathy rats. Moreover, mangiferin was observed to inhibit proliferation of mesangial cells induced by high glucose and the overexpression of collagen type IV of mesangial cells induced by advanced glycation end products. In summary, mangiferin could significantly prevent progression of diabetic nephropathy and improve renal function. Copyright © 2009 John Wiley & Sons, Ltd.
Labdane‐type diterpenes from Hedychium gardnerianum with potent cytotoxicity against human small cell lung cancer cells
Authors: Kumrit Iyared , Suksamrarn Apichart , Meepawpan Puttinan , Songsri Sineenard , Nuntawong Nuchnipa
Published: December 2009

Seven labdane‐type diterpenes, coronarin E, coronarin A, yunnancoronarin A, yunnancoronarin B, hedyforrestin B, villosin, and hedyforrestin C were isolated from the rhizome of Hedychium gardnerianum and evaluated for cytotoxic activity against human small cell lung cancer (NCI‐H187) and non‐cancerous Vero cells. The results showed that villosin exhibited potent cytotoxic activity with IC50 of 0.40 μM, which was higher than that of the drug ellipticine (IC50 1.79 μM). Moreover, ellipticine was very toxic to Vero cells (IC50 7.47 μM) whereas the toxicity of villosin was undetectable at concentration lower than 166.42 μM. The results have indicated that the lactone ring is essential for high cytotoxic activity and that the presence of a hydroxyl group at the 6 or 7 position causes decrease in activity. The very high cytotoxicity against the NCI‐H187 cells and the exceptionally high selectivity index (>416) of villosin suggested that this compound may be used as a potential lead molecule for antitumor therapeutic development. Copyright © 2009 John Wiley & Sons, Ltd.
Promotion of direct angiogenesis in vitro and in vivo by Puerariae flos extract via activation of MEK/ERK‐, PI3K/Akt/eNOS‐, and Src/FAK‐dependent pathways
Authors: Chung Byung‐Hee , Cho Young‐Lai , Kim Jong‐Dai , Jo Heui Sug , Won Moo‐Ho , Lee Hansoo , Ha Kwon‐Soo , Kwon Young‐Geun , Kim Young‐Myeong
Published: December 2009

Puerariae flos has been used for oriental herbal medicine; however, its angiogenic effect has not been elucidated. We found that the extract from Puerariae flos (PFE) increased in vitro angiogenic events, such as endothelial cell proliferation, migration, and tube formation, as well as in vivo neovascularization. These events were followed by the activation of multiple signal modulators, such as extracellular signal‐regulated kinase (ERK), Akt, endothelial nitric oxide synthase (eNOS), nitric oxide production, p38, Src, and focal adhesion kinase (FAK), without increasing vascular endothelial growth factor (VEGF) expression. Inhibition of ERK, Akt, and eNOS suppressed PFE‐induced angiogenic events, and inhibition of p38 and Src activities blocked PFE‐induced endothelial cell migration. PFE did not affect the expression of intracellular adhesion molecule‐1 and vascular cell adhesion molecule‐1 and transendothelial permeability, which are involved in the adverse effects of the well‐known angiogenic inducer VEGF. These results suggest that PFE directly stimulates angiogenesis through the activation of MEK/ERK‐, phosphatidylinositol 3‐kinase/Akt/eNOS‐, and Src/FAK‐dependent pathways, without altering VEGF expression, vascular inflammation, and permeability in vitro and in vivo and may be used as a therapeutic agent for ischemic disease and tissue regeneration. Copyright © 2009 John Wiley & Sons, Ltd.
Carthamus tinctorius flower extract prevents H2O2‐induced dysfunction and oxidative damage in osteoblastic MC3T3‐E1 cells
Authors: Choi Eun Mi , Kim Gun‐Hee , Lee Yong Soo
Published: December 2009

The flowers of Carthamus tinctorius L. (Compositae) have been widely used for enhancing blood circulation and postmenopausal disorder in women. In the present study, the potential protective effects of C. tinctorius flower extract (CFE) against reactive oxygen species (ROS) induced osteoblast dysfunction were investigated using osteoblastic MC3T3‐E1 cells. The osteoblast function was assessed by measuring alkaline phosphatase activity, collagen content, calcium deposition, and RANKL production, and the oxidative status was assessed by measuring intracellular lipid peroxidation, and protein oxidation in osteoblastic MC3T3‐E1 cells. A significant reduction in the alkaline phosphatase activity, collagen, and calcium deposition and an increase in the production of receptor activator of nuclear factor‐kB ligand (RANKL) were observed after 0.3 mM H2O2 addition. The H2O2‐induced alterations were prevented by pre‐incubating the osteoblasts with 2–10 μg/ml CFE for 48 h. When the oxidative stress was induced by H2O2, the increased production of protein carbonyl and malondialdehyde was also reduced at the same CFE concentration. These results demonstrate that C. tinctorius flower can act as a biological antioxidant in a cell culture experimental model and protect osteoblasts from oxidative stress‐induced toxicity. Copyright © 2009 John Wiley & Sons, Ltd.
Antiprotozoal, antimycobacterial and cytotoxic potential of some british green algae
Authors: Spavieri Jasmine , Kaiser Marcel , Casey Rosalyn , Hingley‐Wilson Suzie , Lalvani Ajit , Blunden Gerald , Tasdemir Deniz
Published: December 2009

In the continuation of our search for natural sources for antiprotozoal and antitubercular molecules, we have screened the crude extracts of four green marine algae (Cladophora rupestris, Codium fragile ssp. tomentosoides, Ulva intestinalis and Ulva lactuca) collected from the Dorset area of England. Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani and Mycobacterium tuberculosis were used as test organisms in the in vitro assays. The selective toxicity of the extracts was also determined toward mammalian skeletal myoblast (L6) cells. The crude seaweed extracts had no activity against M. tuberculosis, but showed antiprotozoal activity against at least two protozoan species. All algal extracts were active against T. brucei rhodesiense, with C. rupestris being the most potent one (IC50 value 3.7 μg/ml), whilst only C. rupestris and U. lactuca had moderate trypanocidal activity against T. cruzi (IC50 values 80.8 and 34.9 μg/ml). Again, all four extracts showed leishmanicidal activity with IC50 values ranging between 12.0 and 20.2 μg/ml. None of the extracts showed cytotoxicity toward L6 cells, indicating that their antiprotozoal activity is specific. This is the first study reporting antiprotozoal and antimycobacterial activity of British marine algae. Copyright © 2009 John Wiley & Sons, Ltd.
Euphorbiasteroid reverses P‐glycoprotein‐mediated multi‐drug resistance in human sarcoma cell line MES‐SA/Dx5
Authors: Choi Jung Sook , Kang Nam Sook , Min Yong Ki , Kim Seong Hwan
Published: December 2009

In this study, we evaluated whether euphorbiasteroid isolated from Euphorbia lathyris has the potential to reverse P‐glycoprotein (P‐gp)‐mediated multi‐drug resistance (MDR) by using the drug‐sensitive human sarcoma cell line MES‐SA and its MDR counterpart MES‐SA/Dx5. Interestingly, even at low concentrations of euphorbiasteroid (1–3 μM), it efficiently restored the toxicities of anticancer drugs including vinblastine, taxol and doxorubicin in MES‐SA/Dx5 cells. Additionally, the computational Bayesian model for predicting potential P‐gp substrates or inhibitors revealed that euphorbiasteroid showed 97% probability for substrate likeness having similar molecular features with 50 P‐gp substrates. Consistent with this result, the substrate likeness of euphorbiasteroid was also experimentally confirmed by P‐gp ATPase activity assay. In conclusion, our finding suggested that euphorbiasteroid could be a transport substrate for P‐gp that can effectively inhibit P‐gp‐mediated drug transport and reverse resistance to anticancer drugs in MES‐SA/Dx5 cells. Copyright © 2009 John Wiley & Sons, Ltd.
Chronic treatment of silymarin improves hyperalgesia and motor nerve conduction velocity in diabetic neuropathic rat
Authors: Baluchnejadmojarad Tourandokht , Roghani Mehrdad , Khastehkhodaie Zeynab
Published: December 2009

The effect of chronic silymarin (SM) treatment on hyperalgesia, sciatic motor nerve conduction velocity (MNCV) and oxidative stress in streptozotocin (STZ)‐diabetic neuropathic rat was evaluated. Rats were divided into control, diabetic, SM‐treated control and diabetic, and sodium salisylate (SS)‐treated control and diabetic. SM was administered daily at a dose of 100 mg/kg for two months. Finally, hyperalgesia and sciatic MNCV and oxidative stress markers were assessed. Diabetic rats showed a significant deficit in MNCV and markedly exhibited chemical and thermal hyperalgesia, indicating development of diabetic neuropathy. Antioxidant enzyme superoxide dismutase (SOD) level significantly reduced and malondialdehyde (MDA) level significantly increased in diabetic rats compared to control rats; SM treatment significantly ameliorated the alteration in MNCV, hyperalgesia, MDA level and antioxidant enzyme SOD in diabetic rats. These results clearly suggest the potential effect of SM in prevention and treatment of diabetic neuropathy. Copyright © 2009 John Wiley & Sons, Ltd.
Ground‐based detection of sprites and their parent lightning flashes over Africa during the 2006 AMMA campaign
Authors: Williams E. R. , Lyons W. A. , Hobara Y. , Mushtak V. C. , Asencio N. , Boldi R. , Bór J. , Cummer S. A. , Greenberg E. , Hayakawa M. , Holzworth R. H. , Kotroni V. , Li J. , Morales C. , Nelson T. E. , Price C. , Russell B. , Sato M. , Sátori G. , Shirahata K. , Takahashi Y. , Yamashita K.
Published: December 2009

Sprites have been detected in video camera observations from Niger over mesoscale convective systems in Nigeria during the 2006 AMMA (African Monsoon Multidisciplinary Analysis) campaign. The parent lightning flashes have been detected by multiple Extremely Low Frequency (ELF) receiving stations worldwide. The recorded charge moments of the parent lightning flashes are often in excellent agreement between different receiving sites, and are furthermore consistent with conventional dielectric breakdown in the mesosphere as the origin of the sprites. Analysis of the polarization of the horizontal magnetic field at the distant receivers provides evidence that the departure from linear magnetic polarization at ELF is caused primarily by the day–night asymmetry of the Earth–ionosphere cavity. Copyright © 2009 Royal Meteorological Society
A rapid method for the sampling of atmospheric water vapour for isotopic analysis
Authors: Peters Leon I. , Yakir Dan
Published: December 2009

Analysis of the stable isotopic composition of atmospheric moisture is widely applied in the environmental sciences. Traditional methods for obtaining isotopic compositional data from ambient moisture have required complicated sampling procedures, expensive and sophisticated distillation lines, hazardous consumables, and lengthy treatments prior to analysis. Newer laser‐based techniques are expensive and usually not suitable for large‐scale field campaigns, especially in cases where access to mains power is not feasible or high spatial coverage is required. Here we outline the construction and usage of a novel vapour‐sampling system based on a battery‐operated Stirling cycle cooler, which is simple to operate, does not require any consumables, or post‐collection distillation, and is light‐weight and highly portable. We demonstrate the ability of this system to reproduce δ18O isotopic compositions of ambient water vapour, with samples taken simultaneously by a traditional cryogenic collection technique. Samples were collected over 1 h directly into autosampler vials and were analysed by mass spectrometry after pyrolysis of 1 µL aliquots to CO. This yielded an average error of < ±0.5‰, approximately equal to the signal‐to‐noise ratio of traditional approaches. This new system provides a rapid and reliable alternative to conventional cryogenic techniques, particularly in cases requiring high sample throughput or where access to distillation lines, slurry maintenance or mains power is not feasible. Copyright © 2009 John Wiley & Sons, Ltd.
Laser ablation of ternary As‐S‐Se glasses and time‐of‐flight mass spectrometric study
Authors: Pangavhane Sachinkumar Dagurao , Houška Jan , Wágner Tomáš , Pavlišta Martin , Janča Jan , Havel Josef
Published: December 2009

Ternary chalcogenide As‐S‐Se glasses, important for optics, computers, material science and technological applications, are often made by pulsed laser deposition (PLD) technology but the plasma composition formed during the process is mostly unknown. Therefore, the formation of clusters in a plasma plume from different glasses was followed by laser desorption ionization (LDI) or laser ablation (LA) time‐of‐flight mass spectrometry (TOF MS) in positive and negative ion modes. The LA of glasses of different composition leads to the formation of a number of binary AspSq, AspSer and ternary AspSqSer singly charged clusters. Series of clusters with the ratio As:chalcogen = 3:3 (As3S, As3S2Se+, As3SSe), 3:4 (As3S, As3S3Se+, As3S2Se, As3SSe, As3Se), 3:1 (As3S+, As3Se+), and 3:2 (As3S, As3SSe+, As3Se), formed from both bulk and PLD‐deposited nano‐layer glass, were detected. The stoichiometry of the AspSqSer clusters was determined via isotopic envelope analysis and computer modeling. The structure of the clusters is discussed. Copyright © 2009 John Wiley & Sons, Ltd.
A rapid ultra‐performance liquid chromatography/tandem mass spectrometric methodology for the in vitro analysis of Pooled and Cocktail cytochrome P450 assays
Authors: Alden Peter G. , Plumb Robert S. , Jones Michael D. , Rainville Paul D. , Shave Darcy
Published: December 2009

Drug‐drug interaction evaluations of new pharmaceutical candidates are critical to preventing drug withdrawal and are routinely determined through the use of cytochrome P450 assays. The measurement of the effect of test compounds on the metabolism of known substrates allows for the determination of specific CYP450 isoenzyme inhibition and calculation of IC50 values. A sensitive, high‐throughput ultra‐performance liquid chromatography/tandem mass spectrometric (UPLC/MS/MS) method is presented for the evaluation of CYP450 inhibition. The assay was performed using a cocktail of probe substrates and the results were compared to those obtained with the more time‐consuming methodology utilizing individual substrates. The use of a high‐resolution, sub‐2 µm particle, LC system allowed for a high‐throughput assay of just 1 min. The extra resolution of the UPLC/MS/MS system allowed for the complete resolution of the analytes, with a fast switching MS for comprehensive data collection. The CYP450 inhibition results obtained using the substrate cocktail approach were found to be essentially identical to those obtained using individual substrates. Copyright © 2009 John Wiley & Sons, Ltd.
Tracing the geographical origin of beefs being circulated in Korean markets based on stable isotopes
Authors: Bong Yeon‐Sik , Shin Woo‐Jin , Lee A‐Reum , Kim Young‐Soo , Kim Kangjoo , Lee Kwang‐Sik
Published: December 2009

We have examined the carbon, nitrogen and oxygen isotopic compositions of American, Mexican, Australian, New Zealand and Korean beefs, which are currently being circulated in Korean markets, to check whether stable isotope ratios can identify their country of origin. Each beef exhibited statistically distinct isotopic compositions, especially in oxygen and carbon, because of the different isotopic compositions of their water and cattle feeds. Nevertheless, their isotopic compositions still showed some overlap, especially among USA, Australian, and Korean beefs, which sometimes resulted in significant misidentification when a single isotope was considered. However, the discrimination was generally successful when both the carbon and the oxygen isotopes were used. Copyright © 2009 John Wiley & Sons, Ltd.
Stability analysis for networked control systems based on average dwell time method
Authors: Sun Xi‐Ming , Liu Guo‐Ping , Wang Wei , Rees David
Published: December 2009

This paper studies the problem of the exponential stability of networked control systems (NCSs) with large delay periods, which often appear in the transmission of NCSs. Some new concepts about large delay periods are introduced, and a method based on switching is employed. The maximum allowable transfer interval is obtained such that the considered system is exponentially stable. The criteria obtained contain existing results without considering a large delay period as a special case. An example is given to show the effectiveness of the proposed criteria. Copyright © 2009 John Wiley & Sons, Ltd.
Improving propensity score weighting using machine learning
Authors: Lee Brian K. , Lessler Justin , Stuart Elizabeth A.
Published: December 2009

Machine learning techniques such as classification and regression trees (CART) have been suggested as promising alternatives to logistic regression for the estimation of propensity scores. The authors examined the performance of various CART‐based propensity score models using simulated data. Hypothetical studies of varying sample sizes (n=500, 1000, 2000) with a binary exposure, continuous outcome, and 10 covariates were simulated under seven scenarios differing by degree of non‐linear and non‐additive associations between covariates and the exposure. Propensity score weights were estimated using logistic regression (all main effects), CART, pruned CART, and the ensemble methods of bagged CART, random forests, and boosted CART. Performance metrics included covariate balance, standard error, per cent absolute bias, and 95 per cent confidence interval (CI) coverage. All methods displayed generally acceptable performance under conditions of either non‐linearity or non‐additivity alone. However, under conditions of both moderate non‐additivity and moderate non‐linearity, logistic regression had subpar performance, whereas ensemble methods provided substantially better bias reduction and more consistent 95 per cent CI coverage. The results suggest that ensemble methods, especially boosted CART, may be useful for propensity score weighting. Copyright © 2009 John Wiley & Sons, Ltd.
β-Catenin Signaling Increases in Proliferating NG2+ Progenitors and Astrocytes during Post-Traumatic Gliogenesis in the Adult Brain
Authors: White Bryan D. , Nathe Ryan J. , Maris Don O. , Nguyen Nghi K. , Goodson Jamie M. , Moon Randall T. , Horner Philip J.
Published: December 2009

Wnt/β-catenin signaling can influence the proliferation and differentiation of progenitor populations in the hippocampus and subventricular zone, known germinal centers in the adult mouse brain. It is not known whether β-catenin signaling occurs in quiescent glial progenitors in cortex or spinal cord, nor is it known whether β-catenin is involved in the activation of glial progenitor populations after injury. Using a β-catenin reporter mouse (BATGAL mouse), we show that β-catenin signaling occurs in NG2 chondroitin sulfate proteoglycan+ (NG2) progenitors in the cortex, in subcallosal zone (SCZ) progenitors, and in subependymal cells surrounding the central canal. Interestingly, cells with β-catenin signaling increased in the cortex and SCZ following traumatic brain injury (TBI) but did not following spinal cord injury. Initially after TBI, β-catenin signaling was predominantly increased in a subset of NG2+ progenitors in the cortex. One week following injury, the majority of β-catenin signaling appeared in reactive astrocytes but not oligodendrocytes. Bromodeoxyuridine (BrdU) paradigms and Ki-67 staining showed that the increase in β-catenin signaling occurred in newly born cells and was sustained after cell division. Dividing cells with β-catenin signaling were initially NG2+; however, by four days after a single injection of BrdU, they were predominantly astrocytes. Infusing animals with the mitotic inhibitor cytosine arabinoside prevented the increase of β-catenin signaling in the cortex, confirming that the majority of β-catenin signaling after TBI occurs in newly born cells. These data argue for manipulating the Wnt/β-catenin pathway after TBI as a way to modify post-traumatic gliogenesis.
Identification of a novel “almost neutral” μ‐opioid receptor antagonist in CHO cells expressing the cloned human μ‐opioid receptor
Authors: Sally Elliott J. , Xu Heng , Dersch Christina M. , Hsin Ling‐Wei , Chang Li‐Te , Prisinzano Thomas E. , Simpson Denise S. , Giuvelis Denise , Rice Kenner C. , Jacobson Arthur E. , Cheng Kejun , Bilsky Edward J. , Rothman Richard B.
Published: December 2009

The basal (constitutive) activity of G protein‐coupled receptors allows for the measurement of inverse agonist activity. Some competitive antagonists turn into inverse agonists under conditions where receptors are constitutively active. In contrast, neutral antagonists have no inverse agonist activity, and they block both agonist and inverse agonist activity. The μ‐opioid receptor (MOR) demonstrates detectable constitutive activity only after a state of dependence is produced by chronic treatment with a MOR agonist. We therefore sought to identify novel MOR inverse agonists and novel neutral MOR antagonists in both untreated and agonist‐treated MOR cells. CHO cells expressing the cloned human mu receptor (hMOR‐CHO cells) were incubated for 20 h with medium (control) or 10 μM (2S,4aR,6aR,7R,9S,10aS,10bR)‐9‐(benzoyloxy)‐2‐(3‐furanyl)dodecahydro‐6a,10b‐dimethyl‐4,10‐dioxo‐2H‐naphtho‐[2,1‐c]pyran‐7‐carboxylic acid methyl ester (herkinorin, HERK). HERK treatment generates a high degree of basal signaling and enhances the ability to detect inverse agonists. [35S]‐GTP‐γ‐S assays were conducted using established methods. We screened 21 MOR “antagonists” using membranes prepared from HERK‐treated hMOR‐CHO cells. All antagonists, including CTAP and 6β‐naltrexol, were inverse agonists. However, LTC‐274 ((−)‐3‐cyclopropylmethyl‐2,3,4,4α,5,6,7,7α‐octahydro‐1H‐benzofuro[3,2‐e]isoquinolin‐9‐ol)) showed the lowest efficacy as an inverse agonist, and, at concentrations less than 5 nM, had minimal effects on basal [35S]‐GTP‐γ‐S binding. Other efforts in this study identified KC‐2‐009 ((+)‐3‐((1R,5S)‐2‐((Z)‐3‐phenylallyl)‐2‐azabicyclo[3.3.1]nonan‐5‐yl)phenol hydrochloride) as an inverse agonist at untreated MOR cells. In HERK‐treated cells, KC‐2‐009 had the highest efficacy as an inverse agonist. In summary, we identified a novel and selective MOR inverse agonist (KC‐2‐009) and a novel MOR antagonist (LTC‐274) that shows the least inverse agonist activity among 21 MOR antagonists. LTC‐274 is a promising lead compound for developing a true MOR neutral antagonist. Synapse 64:280–288, 2010. © 2009 Wiley‐Liss, Inc.
GABAA receptors mediate the attenuating effects of a 5‐HT3 receptor antagonist on methamphetamine‐induced behavioral sensitization in mice
Authors: Yoo Ji‐Hoon , Lee Ha‐Kyung , Kim Hyoung‐Chun , Lee Seok‐Yong , Jang Choon‐Gon
Published: December 2009

We previously showed that 5‐HT3 receptors are involved in the development and expression of methamphetamine (MAP)‐induced locomotor sensitization in mice. Here, we examined whether the dopaminergic or the GABAergic systems areinvolved in the attenuating effects of the 5‐HT3 receptor antagonist MDL72222 on MAP‐induced locomotor sensitization. Quantitative autoradiography of D1 ([3H]SCH23390), D2 ([3H]raclopride) receptor, and GABAA receptor benzodiazepine ([3H]flunitrazepam) binding was carried out in the brains of mice treated with chronic MAP and pretreatment with MDL72222. No significant differences were found in D1 and D2 binding between the two groups, suggesting that the attenuating effects of MDL72222 on MAP‐induced locomotor sensitization is not medicated by D1 and D2 receptors. Postsynaptic dopamine (DA) receptor supersensitivity was measured by challenge with apomorphine, a dopamine D1 and D2 receptor agonist, after repeated MAP treatment or pretreatment with MDL72222 before MAP. Apomorphine induced an enhanced locomotor activity in both chronic MAP‐treated mice and mice pretreated with MDL 72222, with no significant differences between the two groups. The binding of [3H]flunitrazepam was significantly decreased in the motor and cingulate cortex, caudate putamen, and nucleus accumbens of mice in the repeated MAP treatment group compared with the control group, and this effect was reversed by pretreatment with MDL72222. This suggested that GABAA benzodiazepine binding sites are involved in the attenuating effects of a 5‐HT3 receptor antagonist on MAP‐induced locomotor sensitization. Synapse 64:274–279, 2010. © 2009 Wiley‐Liss, Inc.
Neonatal quinpirole treatment enhances locomotor activation and dopamine release in the nucleus accumbens core in response to amphetamine treatment in adulthood
Authors: Cope Zackary A. , Huggins Kimberly N. , Sheppard A. Brianna , Noel Daniel M. , Roane David S. , Brown Russell W.
Published: December 2009

Neonatal quinpirole treatment to rats produces long‐term increases in D2receptor sensitivity that persists throughout the animal's lifetime, a phenomenon referred to as D2priming. Male and female Sprague‐dawley rats were administered quinpirole (1 mg kg−1) or saline from postnatal days (P)1–11. At P60, all animals were given an injection of quinpirole (100 μg kg−1), and results showed that rats neonatally treated with quinpirole demonstrated enhanced yawning in response to quinprole, verifying D2receptor priming because yawning is a D2receptor mediated event. Beginning 1–3 days later, locomotor sensitization was tested through administration ofd‐amphetamine (1 mg kg−1) or saline every other day over 14 days, and horizontal activity and turning behavior were analyzed. Findings indicated that D2‐priming enhanced horizontal activity in response to amphetamine in females compared to males at Days 1 and 4 of locomotor sensitization testing, and D2‐priming enhanced turning in response to amphetamine. Seven to ten days after sensitization was complete, microdialysis of the NAcc core was performed using a cumulative dosing regimen of amphetamine (0.1–3.0 mg kg−1). D2‐primed rats administered amphetamine demonstrated a 500% increase in accumbal DA overflow compared to control rats administered amphetamine. Additionally, amphetamine produced a significant increase in NE overflow compared to controls, but this was unaffected by D2priming. These results indicate that D2receptor priming as is produced by neonatal quinpirole treatment robustly enhances behavioral activation and accumbal DA overflow in response to amphetamine, which may underlie increases in psychostimulant use and abuse within the psychotic population where increased D2receptor sensitivity is a hallmark. Synapse 64:289–300, 2010. © 2009 Wiley‐Liss, Inc.