bluuebunny/crossref_metadata_2025 huggingface dataset:
Air flow assisted ionization for remote sampling of ambient mass spectrometry and its application
Authors: He Jiuming , Tang Fei , Luo Zhigang , Chen Yi , Xu Jing , Zhang Ruiping , Wang Xiaohao , Abliz Zeper
Published: March 2011

Ambient ionization methods are an important research area in mass spectrometry (MS) analysis. Under ambient conditions, the gas flow and atmospheric pressure significantly affect the transfer and focusing of ions. The design and implementation of air flow assisted ionization (AFAI) as a novel and effective, remote sampling method for ambient mass spectrometry are described herein. AFAI benefits from a high extracting air flow rate. A systematic investigation of the extracting air flow in the AFAI system has been carried out, and it has been demonstrated not only that it plays a role in the effective capture and remote transport of charged droplets, but also that it promotes desolvation and ion formation, and even prevents ion fragmentation during the ionization process. Moreover, the sensitivity of remote sampling ambient MS analysis was improved significantly by the AFAI method. Highly polar and nonpolar molecules, including dyes, pharmaceutical samples, explosives, drugs of abuse, protein and volatile compounds, have been successfully analyzed using AFAI‐MS. The successful application of the technique to residue detection on fingers, large object analysis and remote monitoring in real time indicates its potential for the analysis of a variety of samples, especially large objects. The ability to couple this technique with most commercially available MS instruments with an API interface further enhances its broad applicability. Copyright © 2011 John Wiley & Sons, Ltd.
Spatial distributions of carbon, nitrogen and sulfur isotope ratios in human hair across the central United States
Authors: Valenzuela Luciano O. , Chesson Lesley A. , O'Grady Shannon P. , Cerling Thure E. , Ehleringer James R.
Published: March 2011

We present data on the carbon (δ13C), nitrogen (δ15N) and sulfur (δ34S) isotope ratios of human hair collected in the central portions of the USA. These elements are incorporated into hair from the diet and thus provide a record of dietary inputs that may also document geospatial patterns. We detected regional differences in hair δ34S values across the USA, with the lowest values in the northern Great Plains and increasing values towards the east, west and south. In contrast, no statistically significant patterns were detected in the spatial variation of human hair δ13C and δ15N values. Using δ34S values and a Geographic Information System approach, we created a map (‘sulfur isoscape’). The accuracy of the map was tested using hair samples not included in its generation. We conclude that sulfur isotope analysis may represent a new tool to investigate the movements and/or region‐of‐origin of humans. Copyright © 2011 John Wiley & Sons, Ltd.
Performance of gas chromatography/tandem mass spectrometry in the analysis of pyrethroid insecticides in environmental and food samples
Authors: Feo M. L. , Eljarrat E. , Barceló D.
Published: March 2011

The performance of gas chromatography coupled with tandem mass spectrometry (GC/MS/MS) was tested for the simultaneous determination of twelve pyrethroid insecticides. First, a comparison of two different ionization modes, electron ionization (EI) and negative chemical ionization (NCI), was carried out using MS and MS/MS. NCI‐MS/MS provided the best results in terms of selectivity and sensitivity giving very low detection limits of 0.11 to 450 fg injected. The reliability of the method was confirmed through the evaluation of quality parameters such as accuracy (70–100%), and repeatability and reproducibility, with coefficients of variation below 15% and 10%, respectively.

The applicability of the GC/MS/MS method to real samples and influence of matrix effects were evaluated through the analysis of spiked water, sediment and milk at 0.25 ng L−1, 5 ng g−1 dry weight (dw) and 25 ng g−1 (dw), respectively, of each pyrethroid insecticide considered. Using GC/NCI‐MS/MS, matrix spectral interferences were minimized providing method limits of detection (MLODs) of 0.05–2.59 ng L−1, 0.10–87.7 pg g−1 dw, 2.29–1071 pg g−1 lipid weight (lw) for water, sediment and milk, respectively. To the best of our knowledge, the MLOD values found in our study were better than those reported in previous studies; in particular for sediment and food samples, they were one order of magnitude lower. Copyright © 2011 John Wiley & Sons, Ltd.
Selective chemical oxidation and depolymerization of switchgrass (Panicum virgatum L.) xylan with oligosaccharide product analysis by mass spectrometry
Authors: Bowman Michael J. , Dien Bruce S. , O'Bryan Patricia J. , Sarath Gautam , Cotta Michael A.
Published: March 2011

Xylan is a barrier to enzymatic hydrolysis of plant cell walls. It is well accepted that the xylan layer needs to be removed to efficiently hydrolyze cellulose; consequently, pretreatment conditions are (in part) optimized for maximal xylan depolymerization or displacement. Xylan consists of a long chain of β‐1,4‐linked xylose units substituted with arabinose (typically α‐1,3‐linked in grasses) and glucuronic acid (α‐1,2‐linked). Xylan has been proposed to have a structural function in plants and therefore may play a role in determining biomass reactivity to pretreatment. It has been proposed that substitutions along xylan chains are not random and, based upon studies of pericarp xylan, are organized in domains that have specific structural functions. Analysis of intact xylan is problematic because of its chain length (> degree of polymerization (d.p.) 100) and heterogeneous side groups. Traditionally, enzymatic end‐point products have been characterized due to the limited products generated. Analysis of resultant arabino‐xylo‐oligosaccharides by mass spectrometry is complicated by the isobaric pentose sugars that primarily compose xylan. In this report, the variation in pentose ring structures was exploited for selective oxidation of the arabinofuranose primary alcohols followed by acid depolymerization to provide oligosaccharides with modified arabinose branches intact. Switchgrass samples were analyzed by hydrophilic interaction chromatography (HILIC)‐liquid chromatography (LC)‐mass spectrometry/mass spectrometry (MSMS) and off‐line nanospray MS to demonstrate the utility of this chemistry for determination of primary hydroxyl groups on oligosaccharide structures, with potential applications for determining the sequence of arabino‐xylo‐oligosaccharides present in plant cell wall material. Published in 2011 by John Wiley & Sons, Ltd.
Robot‐assisted laparoscopic management of cardia carcinoma according to Siewert recommendations
Authors: Patriti Alberto , Ceccarelli Graziano , Ceribelli Cecilia , Bartoli Alberto , Spaziani Alessandro , Cisano Claudio , Cigliano Silvia , Casciola Luciano
Published: March 2011

Background

Resection of cardia and upper gastric carcinoma is considered a demanding procedure in laparoscopic surgery. Robotics could aid laparoscopic dissection of the oesophago–gastric junction and oesophageal anastomosis, enlarging indications for a minimally invasive approach to these tumours.

Methods

Data from 17 consecutive patients with histologically proved cardia carcinoma were collected in a prospective database to assess the feasibility and safety of laparoscopic robot‐assisted radical surgery, using the four‐arm da Vinci surgical system. The type of surgery was chosen according to Siewert recommendations. Outcome measures were conversion rate, intra‐ and post‐operative morbidity and mortality, operative time, blood loss, number of lymph nodes harvested and macroscopic and microscopic evaluation of resection margins.

Results

Seventeen laparoscopic operations were completed without conversion (14 extended gastrectomies, two transhiatal distal oesophagectomies and one transthoracic distal oesophagectomy). Extended lymph node dissection and oesophago–jejunal anastomosis were successfully carried out using the da Vinci system. Mean operative time was 327.2 ± 93.4 min and blood loss 279 ± 199 ml. The mean number of nodes retrieved was 28 ± 9 and all resection margins were negative. There was no mortality and overall morbidity was acceptably low (41.1%). During a mean follow‐up time of 20 months, four recurrences were recorded (two multivisceral, one to the lung and one nodal), with two recurrence‐related deaths.

Conclusions

Robot‐assisted laparoscopic radical surgery of the oesophago–gastric junction is feasible and safe. Longer follow‐up time and randomized studies are needed to evaluate the long‐term outcome and advantages for the patient of this new technology. Copyright © 2011 John Wiley & Sons, Ltd.
Cardioids‐based faster authentication and diagnosis of remote cardiovascular patients
Authors: Sufi Fahim , Khalil Ibrahim , Habib Ibrahim
Published: March 2011

In recent times, dealing with deaths associated with cardiovascular diseases (CVD) has been one of the most challenging issues. The usage of mobile phones and portable Electrocardiogram (ECG) acquisition devices can mitigate the risks associated with CVD by providing faster patient diagnosis and patient care. The existing technologies entail delay in patient authentication and diagnosis. However, for the cardiologists minimizing the delay between a possible CVD symptom and patient care is crucial, as this has a proven impact in the longevity of the patient. Therefore, every seconds counts in terms of patient authentication and diagnosis. In this paper, we introduce the concept of Cardioid based patient authentication and diagnosis. According to our experimentations, the authentication time can be reduced from 30.64 s (manual authentication in novice mobile user) to 0.4398 s (automated authentication). Our ECG based patient authentication mechanism is up to 4878 times faster than conventional biometrics like, face recognition. The diagnosis time could be improved from several minutes to less than 0.5 s (cardioid display on a single screen). Therefore, with our presented mission critical alerting mechanism on wireless devices, minute's worth of tasks can be reduced to second's, without compromising the accuracy of authentication and quality of diagnosis. Copyright © 2011 John Wiley & Sons, Ltd.
Techniques in the Study of Carbon Transfer in Ironmaking
Authors: Longbottom Raymond J. , Monaghan Brian J. , Chapman Michael W. , Nightingale Sharon A. , Mathieson John G. , Nightingale Robert J.
Published: March 2011

In this paper two new approaches to the study of carburisation/decarburisation of iron are detailed. Firstly, a new experimental method focusing on understanding carbon transfer in a non‐traditional ironmaking process, and secondly, a new carbonaceous material (coke analogue) for use in coke laboratory investigations are detailed. The new experimental method was developed to assess the decarburising effects of high titania slags, typical of ironmaking with titaniferous ores or sands. Preliminary experiments found that carbon was being consumed from the metal as it passed through the slag. The coke analogue was developed to address material complexity and heterogeneity issues that often limit and mask important coke phenomena in laboratory studies. Preliminary dissolution experiments using the coke analogue to carburise iron showed that rate of dissolution was consistent with that published for both graphite and industrial coke.
Klaus – an exceptional winter storm over northern Iberia and southern France
Authors: Liberato Margarida L. R. , Pinto Joaquim G. , Trigo Isabel F. , Trigo Ricardo M.
Published: March 2011

The synoptic evolution and impacts of storm ‘Klaus’ that affected Europe on 23–24 January 2009 are assessed. Klaus was the costliest weather hazard event worldwide during 2009. Peak wind gusts reached 55ms‐1 (107kn), accompanied by heavy rain, snow and flooding across Northern Iberia and southern France. Klaus underwent explosive development between the Azores and the Iberian Peninsula at an unusually low latitude. This development was supported by an extended and intense polar jet across the North Atlantic Basin, strong upper‐air divergence associated with a second jet streak and an extraordinary export of tropical moisture into the genesis region. Copyright © 2011 Royal Meteorological Society
On symmetry of nonnegative solutions of elliptic equations
Authors: Poláčik P.
Published: March 2011

We consider the Dirichlet problem for a class of fully nonlinear elliptic equations on a bounded domain

Ω

. We assume that

Ω

is symmetric about a hyperplane

H

and convex in the direction perpendicular to

H

. By a well-known result of Gidas, Ni and Nirenberg and its generalizations, all positive solutions are reflectionally symmetric about

H

and decreasing away from the hyperplane in the direction orthogonal to

H

. For nonnegative solutions, this result is not always true. We show that, nonetheless, the symmetry part of the result remains valid for nonnegative solutions: any nonnegative solution

u

is symmetric about

H

. Moreover, we prove that if

u≢0

, then the nodal set of

u

divides the domain

Ω

into a finite number of reflectionally symmetric subdomains in which

u

has the usual Gidas–Ni–Nirenberg symmetry and monotonicity properties. We also show several examples of nonnegative solutions with a nonempty interior nodal set.

Nous considérons le problème de Dirichlet pour une classe dʼéquations elliptiques complètement non-linéaires sur un domaine borné

Ω

. Nous supposons que

Ω

est symétrique par rapport à un hyperplan

H

et convexe dans la direction perpendiculaire à

H

. Par un résultat bien connu de Gidas, Ni et Nirenberg ainsi que par ses généralisations, toutes les solutions positives sont symétriques par rapport à une réflextion de

H

et décroissent à partir de leur distance de lʼhyperplan dans la direction orthogonale à

H

. Pour les solutions non-négatives, ce résultat nʼest pas toujours vrai. Nous montrons que, néanmoins, le résultat sur la symétrie reste valable pour les solutions positives : toute solution non-négative

u

est symétrique par rapport à

H

. En outre, nous montrons que si

u≢0

, alors lʼensemble nodal de

u

divise le domaine

Ω

en un nombre fini de sous-domaines symétriques sous réflextion dans lesquels

u

possède la symétrie habituelle de Gidas–Ni–Nirenberg et des propriétés de monotonie. Nous montrons aussi plusieurs exemples de solutions positives avec un ensemble nodal intérieur non vide.
Measurement of milk clotting activity by rotational viscometry
Authors: Jacob Mandy , Schmidt Martin , Jaros Doris , Rohm Harald
Published: March 2011

Standard method for the determination of the activity of milk coagulants is the rotating bottle method, where clotting time is defined as the time when visually observable flocculation starts. Aim of this study was to verify whether it is possible to determine milk clotting time by rotational viscometry. Using three different coagulants and reconstituted milk of different pH and temperature, flocculation time and viscosity in steady shear was determined, and milk gelation was monitored by small amplitude oscillating shear rheometry. The results show that, independent of pH and temperature, milk clotting time is related to an apparent viscosity of 7·24±0·45 mPa.s, indicating that rotational viscometry can be used for the screening of flocculation time with an accuracy of approximately 6%.
Development of a method based on chemometric analysis of Raman spectra for the discrimination of heterofermentative lactobacilli
Authors: Mobili Pablo , Araujo-Andrade Cuauhtémoc , Londero Alejandra , Frausto-Reyes Claudio , Tzonchev Rumen Ivanov , De Antoni Graciela L , Gómez-Zavaglia Andrea
Published: March 2011

In this work, a method based on Raman spectroscopy in combination with Principal Component Analysis (PCA) and Partial Least Square-Discriminant Analysis (PLS-DA) has been developed for the rapid differentiation of heterofermentative related lactobacilli. In a first approach, Lactobacillus kefir strains were discriminated from other species of heterofermentative lactobacilli: Lb. parakefir and Lb. brevis. After this first approach, PCA allowed for a clear differentiation between Lb. parakefir and Lb.brevis. For the first level of discrimination, PCA was performed on the whole spectra and also on delimited regions, defined taking into consideration the loading values. The best regions allowing a clear differentiation between Lb. kefir and non-Lb. kefir strains were found to be: the 1700–1500 cm−1, 1500–1185 cm−1 and 1800–400 (whole spectrum) cm−1 Raman ranges. In order to develop a classification rule, PLS-DA was carried out on the mentioned regions. This method permitted the discrimination and classification of the strains under study in two groups: Lb. kefir and non-Lb. kefir. The model was further validated using lactobacilli strains from different culture collections or strains isolated from kefir grains previously identified using molecular methods. The second approach based on PCA was also performed on the whole spectra and on delimited regions, being the regions 1700–1500 cm−1, 1500–1185 cm−1 and 1185–1020 cm−1, i.e., those allowing the clearest discrimination between Lb. parakefir and Lb. brevis. The results obtained in this work, allowed a clear discrimination within heterofermentative lactobacilli strains, proteins being the biological structures most determinant for this discrimination.
Sheath vaporization of a monodisperse fuel-spray jet
Authors: ARRIETA-SANAGUSTÍN J. , SÁNCHEZ A. L. , LIÑÁN A. , WILLIAMS F. A.
Published: March 2011

The group vaporization of a monodisperse fuel-spray jet discharging into a hot coflowing gaseous stream is investigated for steady flow by numerical and asymptotic methods with a two-continua formulation used for the description of the gas and liquid phases. The jet is assumed to be slender and laminar, as occurs when the Reynolds number is moderately large, so that the boundary-layer form of the conservation equations can be employed in the analysis. Two dimensionless parameters are found to control the flow structure, namely the spray dilution parameter λ, defined as the mass of liquid fuel per unit mass of gas in the spray stream, and the group vaporization parameter ϵ, defined as the ratio of the characteristic time of spray evolution due to droplet vaporization to the characteristic diffusion time across the jet. It is observed that, for the small values of ϵ often encountered in applications, vaporization occurs only in a thin layer separating the spray from the outer droplet-free stream. This regime of sheath vaporization, which is controlled by heat conduction, is amenable to a simplified asymptotic description, independent of ϵ, in which the location of the vaporization layer is determined numerically as a free boundary in a parabolic problem involving matching of the separate solutions in the external streams, with appropriate jump conditions obtained from analysis of the quasi-steady vaporization front. Separate consideration of dilute and dense sprays, corresponding, respectively, to the asymptotic limits λ ≪ 1 and λ ≫ 1, enables simplified descriptions to be obtained for the different flow variables, including explicit analytic expressions for the spray penetration distance.
Paediatric coronary artery bypass grafting for coronary hypoperfusion late after arterial switch operation
Authors: Bakhtiary Farhad , Bellinghausen Wilfried , Kostelka Martin
Published: March 2011

A case of left main coronary artery stenosis is presented in a boy late after an arterial switch operation, with significant ischaemia during exercise with good collateralisation through the right coronary artery. The problem was successfully managed with minimally invasive off-pump coronary artery bypass through median re-sternotomy.
Subjective Memory in Multiple Sclerosis is Associated with Initial-Trial Learning Performance
Authors: Krch Denise , Sumowski James F. , DeLuca John , Chiaravalloti Nancy
Published: March 2011

Subjective reports of memory functioning are often included as part of neuropsychological evaluations. However, information from subjective measures often conflicts with formal testing results. The current study explored the relationships among self-reported memory functioning and objective learning and memory measures. Sixty-four multiple sclerosis (MS) patients completed a self-report memory questionnaire (Memory Functioning Questionnaire, MFQ) and objective measures of learning and memory (California Verbal Learning Test-II, CVLT-II; Open-Trial Selective Reminding Test, OT-SRT; and Prose Memory, PM). Significant positive correlations were found between self-reported memory functioning and recall following initial exposure to material: OT-SRT Trial 1 (r = .42; p = .001); CVLT-II Trial 1 (r = .39; p = .002): PM Immediate Recall (r = .28; p = .028). Subjective memory was unrelated to recall performance on subsequent learning trials, aggregate learning scores, or delayed free recall. Results suggest that self-reported memory functioning in MS patients may be specifically related to single-trial learning. (JINS, 2011, 17, 557–561)
A model of evapotranspiration based on the theory of maximum entropy production
Authors: Wang Jingfeng , Bras R. L.
Published: March 2011

Building on a proof‐of‐concept study of energy balance over dry soil, a model of evapotranspiration is proposed based on the theory of maximum entropy production (MEP). The MEP formalism leads to an analytical solution of evaporation rate (latent heat flux), together with sensible and ground heat fluxes, as a function of surface soil temperature, surface humidity, and net radiation. The model covers the entire range of soil wetness from dry to saturation. The MEP model of transpiration is formulated as a special case of bare soil evaporation. Test of the MEP model using field observations indicates that the model performs well over bare soil and canopy.
Strong Quake Strikes Japan
Authors: Showstack Randy
Published: March 2011

As Eos was about to go to press, a powerful earthquake with a preliminary estimated magnitude of 8.9 shook the northeast coast of Japan on 11 March at 05:46:23 UTC. It is the largest known earthquake along the Japan Trench subduction zone since 869 A.D. or earlier, Brian Atwater, geologist with the U.S. Geological Survey (USGS), told Eos. The quake's magnitude would place it fifth in terms of any earthquake magnitude worldwide since at least 1900, according to information from the USGS Earthquake Hazards Program. The amount of energy released in the quake—which occurred 130 kilometers east of Sendai, Honshu, at a depth of 24.4 kilometers—was equivalent to the energy from 30 earthquakes the size of the 1906 quake in San Francisco, Calif., according to David Applegate, USGS senior science advisor for earthquake and geologic hazards. He said the economic losses from the shaking are estimated to be in the tens of billions of dollars.
A U.S. Strategy for Regulating the Geologic Sequestration of Carbon Dioxide
Authors: Morgan M. Granger , McCoy Sean T.
Published: March 2011

The United States produces more than 70% of its electricity from fossil fuels and nearly 50% from coal alone [U.S. Energy Information Administration, 2009]. Worldwide, the percentages are similar, making coal the single largest fuel source (42%) for electricity generation, followed by natural gas (21%) [International Energy Agency, 2009]. Dramatic improvements in the efficiency of electricity use and expanded use of renewable and nuclear energy can make important contributions to reducing carbon dioxide (CO2) emissions from electricity generation. However, we see no way to achieve an order of magnitude reduction in those emissions by the latter part of this century without some continued use of fossil fuels [Morgan et al., 2005]. This means that an essential part of any portfolio for emissions reduction will be technology to capture CO2 and permanently sequester it in suitable geologic formations.
Human immunology: a case for the ascent of non‐furry immunology
Authors: Khanna Rajiv , Burrows Scott R
Published: March 2011

Our understanding of the significance and complexity of the chemokine superfamily has increased at an explosive pace over the last decade. Although this pace may be slowing down, many questions remain in this field. The February 2011 Special Feature on Chemokines reviews some of these issues: the CXCR3/CXCL9/CXCL10/CXCL11 axis; the role of chemokines in the thymus; and the function of the atypical chemokine receptors DARC and D6.
Life Expectancy and Life Expectancy With Disability of Normal Weight, Overweight, and Obese Smokers and Nonsmokers in Europe
Authors: Majer Istvan M. , Nusselder Wilma J. , Mackenbach Johan P. , Kunst Anton E.
Published: March 2011

The goal of this study was to estimate life expectancy (LE) and LE with disability (LwD) among normal weight, overweight, and obese smokers and nonsmokers in Western Europe. Data from four waves (1998–2001) of the European Community Household Panel (ECHP) were used; a standardized multipurpose annual longitudinal survey. Self‐reported health and socioeconomic information was collected repeatedly using uniform questionnaires for 66,331 individuals in nine countries. Health status was measured in terms of disability in daily activities. Multistate Markov (MSM) models were applied to obtain hazard ratios (HRs) and age‐specific transition rates according to BMI and smoking status. Multistate life tables were computed using the predicted transition probabilities to estimate LE and LwD. Significant associations were observed between disability incidence and BMI (HR = 1.15 for overweight, HR = 1.64 for obese, compared to normal weight). The risk of mortality was negatively associated with overweight status among disabled (HR = 0.77). Overweight people had higher LE than people with normal‐weight and obesity. Among women, overweight and obese nonsmokers expect 3.6 and 6.1 more years of LwD than normal weight persons, respectively. In contrast, daily smokers expect lower LE but a similar LwD. The same patterns were observed among people with high education and those with low education. To conclude, daily smoking is associated with mortality more than with disability, whereas obesity is associated with disability more than with mortality. The findings suggest that further tobacco control would contribute to increasing LE, while tackling the obesity epidemic is necessary to prevent an expansion of disability.
Comparative Effects of the Long‐Acting GLP‐1 Receptor Ligands, Liraglutide and Exendin‐4, on Food Intake and Body Weight Suppression in Rats
Authors: Hayes Matthew R. , Kanoski Scott E. , Alhadeff Amber L. , Grill Harvey J.
Published: March 2011

The glucagon‐like‐peptide‐1 receptor (GLP‐1R) agonists, liraglutide (Victoza) and the synthetic product of exendin‐4 (Byetta), are approved for type II diabetes mellitus (T2DM) treatment and may be efficacious in obesity treatment as well, in part, due to the drugs' resistance to enzymatic degradation and prolonged half‐life relative to endogenous GLP‐1. To address the need to directly compare the food intake‐ and body weight‐suppressive effects of these two GLP‐1R ligands, acute and chronic dosing experiments were performed. Once‐daily (q.d.) exendin‐4 (0, 0.33, 1.5, and 3.0 µg/kg) and liraglutide (0, 50, 100, and 300 µg/kg, q.d.) both reduced the chow intake in nonobese rats in a dose‐dependent fashion following either intraperitoneal (IP) or subcutaneous (SC) administration, whereas only liraglutide reduced 24 and 48 h body weight in nonobese, chow‐maintained rats. Chow intake and body weight suppression by liraglutide were of greater magnitude and shorter latency following IP compared to SC delivery, whereas for exendin‐4, the magnitude of intake‐suppression was similar for IP and SC administration. The effects of chronic delivery (7 consecutive days; IP) of liraglutide (25 and 50 µg/kg; q.d.) and exendin‐4 (3 µg/kg; q.d. and twice‐daily (b.i.d.)) on food intake and body weight were also examined in diet‐induced obese (DIO) rats. Liraglutide (50 µg/kg q.d.) and exendin‐4 (3 µg/kg b.i.d.) were comparable in suppressing overall high fat/sucrose diet (HFS; 60% kcal from fat) intake. Both drugs regimens yielded marked weight loss over the 7‐day period. The weight loss effect of liraglutide was achieved in the first 2 days and remained stable for the duration of the experiment; weight loss with exendin‐4 appeared more linear over the 7‐day period. In conclusion, administration of the GLP‐1R ligands, exendin‐4 (b.i.d.) and liraglutide (q.d.), lead to comparable and pronounced suppression of food intake and body weight in DIO rats, suggesting a potential role for these drugs as a clinical tool for obesity treatment.
Progress on lamellarins
Authors: Pla Daniel , Albericio Fernando , Álvarez Mercedes
Published: March 2011

The latest developments towards the synthesis of lamellarins, their structure–activity relationship and advances in the mechanism of action are described.
Biochemical characterization of human HIF hydroxylases using HIF protein substrates that contain all three hydroxylation sites
Authors: Pappalardi Melissa B. , McNulty Dean E. , Martin John D. , Fisher Kelly E. , Jiang Yong , Burns Matthew C. , Zhao Huizhen , Ho Thau , Sweitzer Sharon , Schwartz Benjamin , Annan Roland S. , Copeland Robert A. , Tummino Peter J. , Luo Lusong
Published: March 2011

The HIF (hypoxia-inducible factor) plays a central regulatory role in oxygen homoeostasis. HIF proteins are regulated by three Fe(II)- and α-KG (α-ketoglutarate)-dependent prolyl hydroxylase enzymes [PHD (prolyl hydroxylase domain) isoenzymes 1–3 or PHD1, PHD2 and PHD3] and one asparaginyl hydroxylase [FIH (factor inhibiting HIF)]. The prolyl hydroxylases control the abundance of HIF through oxygen-dependent hydroxylation of specific proline residues in HIF proteins, triggering subsequent ubiquitination and proteasomal degradation. FIH inhibits the HIF transcription activation through asparagine hydroxylation. Understanding the precise roles and regulation of these four Fe(II)- and α-KG-dependent hydroxylases is of great importance. In the present paper, we report the biochemical characterization of the first HIF protein substrates that contain the CODDD (C-terminal oxygen-dependent degradation domain), the NODDD (N-terminal oxygen-dependent degradation domain) and the CAD (C-terminal transactivation domain). Using LC-MS/MS (liquid chromatography–tandem MS) detection, we show that all three PHD isoenzymes have a strong preference for hydroxylation of the CODDD proline residue over the NODDD proline residue and the preference is observed for both HIF1α and HIF2α protein substrates. In addition, steady-state kinetic analyses show differential substrate selectivity for HIF and α-KG in reference to the three PHD isoforms and FIH.
The role of oxidized cytochrome c in regulating mitochondrial reactive oxygen species production and its perturbation in ischaemia
Authors: Pasdois Philippe , Parker Joanne E. , Griffiths Elinor J. , Halestrap Andrew P.
Published: March 2011

Oxidized cytochrome c is a powerful superoxide scavenger within the mitochondrial IMS (intermembrane space), but the importance of this role in situ has not been well explored. In the present study, we investigated this with particular emphasis on whether loss of cytochrome c from mitochondria during heart ischaemia may mediate the increased production of ROS (reactive oxygen species) during subsequent reperfusion that induces mPTP (mitochondrial permeability transition pore) opening. Mitochondrial cytochrome c depletion was induced in vitro with digitonin or by 30 min ischaemia of the perfused rat heart. Control and cytochrome c-deficient mitochondria were incubated with mixed respiratory substrates and an ADP-regenerating system (State 3.5) to mimic physiological conditions. This contrasts with most published studies performed with a single substrate and without significant ATP turnover. Cytochrome c-deficient mitochondria produced more H2O2 than control mitochondria, and exogenous cytochrome c addition reversed this increase. In the presence of increasing [KCN] rates of H2O2 production by both pre-ischaemic and end-ischaemic mitochondria correlated with the oxidized cytochrome c content, but not with rates of respiration or NAD(P)H autofluorescence. Cytochrome c loss during ischaemia was not mediated by mPTP opening (cyclosporine-A insensitive), neither was it associated with changes in mitochondrial Bax, Bad, Bak or Bid. However, bound HK2 (hexokinase 2) and Bcl-xL were decreased in end-ischaemic mitochondria. We conclude that cytochrome c loss during ischaemia, caused by outer membrane permeabilization, is a major determinant of H2O2 production by mitochondria under pathophysiological conditions. We further suggest that in hypoxia, production of H2O2 to activate signalling pathways may be also mediated by decreased oxidized cytochrome c and less superoxide scavenging.
Structural investigation of inhibitor designs targeting 3-dehydroquinate dehydratase from the shikimate pathway of Mycobacterium tuberculosis
Authors: Dias Marcio V. B. , Snee William C. , Bromfield Karen M. , Payne Richard J. , Palaninathan Satheesh K. , Ciulli Alessio , Howard Nigel I. , Abell Chris , Sacchettini James C. , Blundell Tom L.
Published: March 2011

The shikimate pathway is essential in Mycobacterium tuberculosis and its absence from humans makes the enzymes of this pathway potential drug targets. In the present paper, we provide structural insights into ligand and inhibitor binding to 3-dehydroquinate dehydratase (dehydroquinase) from M. tuberculosis (MtDHQase), the third enzyme of the shikimate pathway. The enzyme has been crystallized in complex with its reaction product, 3-dehydroshikimate, and with six different competitive inhibitors. The inhibitor 2,3-anhydroquinate mimics the flattened enol/enolate reaction intermediate and serves as an anchor molecule for four of the inhibitors investigated. MtDHQase also forms a complex with citrazinic acid, a planar analogue of the reaction product. The structure of MtDHQase in complex with a 2,3-anhydroquinate moiety attached to a biaryl group shows that this group extends to an active-site subpocket inducing significant structural rearrangement. The flexible extensions of inhibitors designed to form π-stacking interactions with the catalytic Tyr24 have been investigated. The high-resolution crystal structures of the MtDHQase complexes provide structural evidence for the role of the loop residues 19–24 in MtDHQase ligand binding and catalytic mechanism and provide a rationale for the design and efficacy of inhibitors.
Anti-ischaemic effects of bilobalide on neonatal rat cardiomyocytes and the involvement of the platelet-activating factor receptor
Authors: Maerz Stefanie , Liu Chun-Hua , Guo Wei , Zhu Yi-Zhun
Published: March 2011

Terpene trilactones from Ginkgo biloba have been investigated extensively for their antioxidant and anti-ischaemic activities on the brain and the heart, but the mechanisms of these effects remain unclear. For the present study, a terpenoid constituent from G. biloba, bilobalide, was screened for protective effects on the ischaemic heart and the involvement of the PAFR [PAF (platelet-activating factor) receptor] and the enzyme that degrades PAF, PAF-AH (PAF acetylhydrolase) during hypoxia. The PAF pathway is supposed to play a role in hypoxia and its regulation may prevent or alleviate MI (myocardial infarction). Cardiomyocytes from neonatal rat hearts were cultured and treated with different concentrations of bilobalide (500–0.5 ng/ml). After being subjected to a hypoxic environment, the cells' viability was evaluated and proteins as well as RNA were extracted for analysis by Western blotting and RT–PCR (reverse transcription PCR) respectively. With the MI model we tested for bilobalide's cardioprotective effects and the involvement of PAFR and PAF-AH. Bilobalide (5 ng/ml) significantly decreased the mortality of cells in a concentration-dependent way. mRNA expression of PAFR was up-regulated in hypoxic cells but in the groups treated with bilobalide, its expression was down-regulated to the level of the normal control. In hypoxic tissue, PAFR protein expression was also up-regulated, but was reduced in the bilobalide (10 mg/kg of body weight) treated group. Our results indicate that PAF and its receptor may be involved in the cellular response of cardiomyocytes to hypoxia and that bilobalide may interact with this receptor to exert its cardioprotective effects.
Celecoxib reduces fluidity and decreases metastatic potential of colon cancer cell lines irrespective of COX-2 expression
Authors: Sade Aslı , Tunçay Seda , Çimen İsmail , Severcan Feride , Banerjee Sreeparna
Published: March 2011

CLX (celecoxib), a selective COX-2 (cyclo-oxygenase-2) inhibitor, has numerous pleiotropic effects on the body that may be independent of its COX-2 inhibitory activity. The cancer chemopreventive ability of CLX, particularly in CRC (colorectal cancer), has been shown in epidemiological studies. Here we have, for the first time, examined the biophysical effects of CLX on the cellular membranes of COX-2 expressing (HT29) and COX-2 non-expressing (SW620) cell lines using ATR-FTIR (attenuated total reflectance–Fourier transform IR) spectroscopy and SL-ESR (spin label–ESR) spectroscopy. Our results show that CLX treatment decreased lipid fluidity in the cancer cell lines irrespective of COX-2 expression status. As metastatic cells have higher membrane fluidity, we examined the effect of CLX on the metastatic potential of these cells. The CLX treatment efficiently decreased the proliferation, anchorage-independent growth, ability to close a scratch wound and migration and invasion of the CRC cell lines through Matrigel. We propose that one of the ways by which CLX exerts its anti-tumorigenic effects is via alterations in cellular membrane fluidity which has a notable impact on the cells' metastatic potential.
Disturbance in function and expression of condensin affects chromosome compaction in HeLa cells
Authors: Zhai Lei , Wang Hongzhen , Tang Wen , Liu Wenguang , Hao Shui , Zeng Xianlu
Published: March 2011

Condensin, a major non‐histone protein complex on chromosomes, is responsible for the formation of rod‐shaped chromosome in mitosis. A heterodimer composed of SMC2 (structural maintenance of chromosomes) and SMC4 subunits constitutes the core part of condensin. Although extensive studies have been done in yeast, fruit fly and Xenopus to uncover the mechanisms and molecular nature of SMC proteins, little is known about the complex in mammalian cells. We have conducted a series of experiments to unveil the nature of condensin complex in human chromosome formation. The results show that overexpression of the C‐terminal domain of SMC subunits disturbs chromosome condensation, leading to formation of swollen chromosomes, while knockdown of SMC subunits severely disturbs mitotic chromosome formation, resulting in chromatin bridges between daughter cells and multiple nuclei in single cells. The salt extraction assay indicates that a fraction of the condensin complex is bound to chromatin in interphase, but most of the condensin bind to chromatin at the onset of mitosis. Thus, disturbance in condensin function or expression affects chromosome condensation and influences mitotic progression.
βig‐h3 regulates store‐operated Ca2+ entry and promotes the invasion of human hepatocellular carcinoma cells
Authors: Guo Yun‐Shan , Tang Juan , Chen Bo , Huang Wan , Li Yong , Cui Hong‐Yong , Zhang Xin , Wang Shi‐Jie , Chen Zhi‐Nan , Jiang Jian‐Li
Published: March 2011

βig‐h3 is a TGF‐β (transforming growth factor β)‐induced ECM (extracellular matrix) protein that induces the secretion of MMPs (matrix metalloproteinases). However, the mechanism of induction is yet to be established. In this study, siRNAs (small interfering RNAs) targeted against βig‐h3 were transfected into SMMC‐7721 cells [a HCC (human hepatocellular carcinoma) cell line] to knockdown the expression of βig‐h3. We found that NiCl2, a potent blocker of extracellular Ca2+ entry, reduced βig‐h3‐induced secretion of MMP‐2 and −9. Further investigation suggested that reduction in the levels of βig‐h3 decreased the secretion of MMP‐2 and −9 that was enhanced by an increase in the concentration of extracellular Ca2+. SNAP (S‐nitroso‐N‐acetylpenicillamine), a NO (nitric oxide) donor, and 8‐Br‐cGMP (8‐bromo‐cGMP) inhibited thapsigargin‐induced Ca2+ entry and MMP secretion in the invasive potential of human SMMC‐7721 cells. Further, the inhibitory effects of 8‐Br‐cGMP and SNAP could be significantly enhanced by down‐regulating βig‐h3. βig‐h3 attenuates the negative regulation of NO/cGMP‐sensitive store‐operated Ca2+ entry. Our findings suggest that the expression of βig‐h3 might play an important role in the regulation of store‐operated Ca2+ entry to increase the invasive potential of HCC cells.
Biserrula and subterranean clover can co-exist during the vegetative phase but are out-competed by capeweed
Authors: Conning S. A. , Renton M. , Ryan M. H. , Nichols P. G. H.
Published: March 2011

Biserrula (Biserrula pelecinus L.) is a recently domesticated annual pasture legume developed for ley farming systems that have traditionally relied upon subterranean clover (Trifolium subterraneum L.). This study examined competitive interactions between biserrula and subterranean clover and the common broad-leaf weed capeweed (Arctotheca calendula L.) during seedling establishment and vegetative growth, in order to develop guidelines for successful legume pasture management. Two glasshouse experiments were conducted to investigate the allocation of biomass to roots and shoots in biserrula, capeweed, and subterranean clover and its relationship with competitive ability in the first 100 days after sowing. In Experiment 1, capeweed had a higher relative growth rate of shoots and roots than the two legumes and developed a more extensive root system. Experiment 2 consisted of growing binary mixtures of the three species at different densities. The effect of competition on the biomass of biserrula, capeweed, and subterranean clover was best modelled by a power–exponential model. Increasing capeweed densities suppressed the biomass production of both biserrula and subterranean clover, whereas capeweed biomass increased with increasing densities of subterranean clover. This study suggests that the competitive advantage of capeweed is mainly conferred during the seedling stage. It also suggests that biserrula and subterranean clover germinating at the same time can co-exist as a mixed sward, at least up until flowering, if biserrula density is high relative to subterranean clover.
Seasonal changes in leaf and stem loline alkaloids in meadow fescue
Authors: Patchett Brian , Gooneratne Ravi , Fletcher Lester , Chapman Bruce
Published: March 2011

Leaf and stem loline alkaloid concentration in 10 European meadow fescue (Festuca pratensis Huds.) lines grown in a field in Canterbury, New Zealand, were determined in samples collected six times between early spring 2004 and late autumn 2005. Significant differences in loline alkaloid concentrations were noted between lines and between harvest times. Higher total loline alkaloid concentrations (up to 4990 µg g–1) were found in stems compared to leaf (up to 1770 µg g–1). However, the seasonal accumulation pattern of different loline alkaloid concentrations in leaf and stem varied. In most lines, stem loline concentration peaked sharply in late spring and declined during early summer and autumn. The seasonal pattern of leaf loline alkaloid concentration followed the stem concentration except for a sharp decline in early summer followed by an increase in late summer. In most instances, the concentration of N-formyl loline was the highest > N-acetyl loline > N-acetyl norloline > N-methyl loline. The possible role of stem and leaf loline alkaloids to deter pasture-feeding insects is briefly discussed.
Ferroelectricity in ultrathin asymmetric ferroelectric tunnel junctions: vanishing critical thickness
Authors: Zheng Yue , Chen W J , Woo C H , Wang Biao
Published: March 2011

Equations (8) and (9) on page 3 contain some typographical errors. The terms +(ζ1- ζ2)P_ in equation (8) and +ζ1- ζ2/hin equation (9) should be revised as -(ζ1- ζ2)P_ and -ζ1- ζ2/h, respectively. So figure 4(b) should be as shown in the pdf file. Note that these typographical errors do not affect any results in the paper.
Growth of High Magnetic α-Fe2O3 and Fe3O4 Nanowires via an Oxide Assisted Vapor-Solid Process
Authors: Chang Ming , Hsu Nai-feng
Published: March 2011

We describes a controllable synthesis procedure for growing α-Fe2O3 and Fe3O4 nanowires. High magnetic hematite α-Fe2O3 nanowires are successfully grown on Fe0.5Ni0.5 alloy substrates via an oxide assisted vapor-solid process. Experimental results also indicate that previous immersion of the substrates in a solution of oxalic acid causes the grown nanowires to convert gradually into magnetite (Fe3O4) nanowires. Additionally, the saturated state of Fe3O4 nanowires is achieved as the oxalic acid concentration reaches 0.75 mol/L. The average diameter and length of nanowires expands with an increasing operation temperature and the growth density of nanowires accumulates with an increasing gas flux in the vapor-solid process. The growth mechanism of α-Fe2O3 and Fe3O4 nanowires is also discussed. The results demonstrate that the entire synthesis of nanowires can be completed within 2 h.
Synthesis and Characterization of Supported CuInSe2 Nanorod Arrays on Rigid Substrates
Authors: Zhang Zhong-wei , Li Ji , Liu Ji-lei , Zhu Chang-fei
Published: March 2011

Copper indium diselenide nanorod arrays were electrodeposited on tungsten/silicon rigid substrates using porous anodic alumina as growth template. The porous anodic alumina templates were prepared by anodizing aluminum films which were sputtered onto the tungsten/silicon substrates. A selective chemical etching was used to penetrate the barrier layer at the bottom of the alumina channels before electrodeposition, which enables direct electrical and chemical contact with the underside substrate electrode. The as-deposited samples were annealed at 450 °C in vacuum. Scanning electron microscopy revealed that the nanorods were dense and compact with diameter of about 100 nm, length of approximate 1 μm, and the aspect ratio of 10. X-ray diffraction, micro-Raman spectroscopy, and high resolution transmission electron microscopy showed that chalcopyrite polycrystalline structure and high purity CuInSe2 nanorods were obtained. The grain size was large in the rod axial direction. Energy-dispersive X-ray spectroscopy showed the composition was nearly stoichiometric. The energy band gap of this nanorod arrays was analyzed by fundamental absorption spectrum and was evaluated to be 0.96 eV.
Theoretical Study on Decomposition of CF3OH Catalyzed by Water Dimer and Ammonia
Authors: Long Bo , Tan Xing-feng , Long Zheng-wen , Ren Da-sen , Zhang Wei-jun
Published: March 2011

The G3 and CBS-QB3 theoretical methods are employed to study the decomposition of CF3OH into FCFO and HF by water, water dimmer, and ammonia. The decomposition of CF3OH into FCFO and HF is unlikely to occur in the atmosphere due to the high activated energy of 88.7 kJ/mol at the G3 level of theory. However, the computed results predict that the barrier for unimolecular decomposition of CF3OH is decreased to 25.1 kJ/mol from 188.7 kJ/mol with the aid of NH3 at the G3 level of theory, which shows that the ammonia play a strong catalytic effect on the split of CF3OH. In addition, the calculated rate constants show that the decomposition of CF3OH by NH3 is faster than those of H2O and the water dimmer by 109 and 105 times respectively. The rate constants combined with the corresponding concentrations of these species demonstrate that the reaction CF3OH with NH3 via TS4 is of great importance for the decomposition of CF3OH in the atmosphere.