bluuebunny/crossref_metadata_2025 huggingface dataset:
Controls on a scale explicit analysis of sheet erosion
Authors: Oakes E. G. M. , Hughes J. C. , Jewitt G. P. W. , Lorentz S. A. , Chaplot V.
Published: January 2012

Although the impact of sheet erosion on the evolution of soils, soil properties and associated ecosystem services across landscapes is undisputed, there are still large uncertainties in the estimation of sheet erosion, as the results obtained are highly scale dependent. Consequently, there is a need to develop a scale‐explicit understanding of sediment erosion yields, from microplot to hillslope through to plot, to surmount actual erosion modelling flaws and to improve guidance for erosion mitigation. The main objective of this study was to compare sediment yields from small and large plots installed under different environmental conditions and to interpret these results in terms of the main mechanisms and controlling factors of sheet erosion. Fifteen 1 × 1 m² and ten 2 × 5 m² plots were installed on a hillslope in the foothills of the Drakensberg, South Africa. Data of runoff, sediment concentration (SC), soil loss (SL) and rainfall characteristics obtained during the 2009–2010 rainy season at the two spatial scales and from different soils, vegetation cover, geology and topographic conditions were used to identify the main controlling factors of sheet erosion. Scale ratios for SC and SL were subsequently calculated to assess the level of contribution of rain‐impacted flow (RIF) to overall sheet erosion. The average runoff rate (n = 17 events) ranged between 4.9 ± 0.4 L m‐2 on 1 m2 and 5.4 ± 0.6 L m2 on 10 m2, which did not correspond to significant differences at P < 0.05 level. Sediment losses were significantly higher on the 10 m2 plots, compared with the 1 m2 plots (2.2 ± 0.4 vs 1.5 ± 0.2 g L‐1 for SC; 9.8 ± 1.8 vs 3.2 ± 0.3 g m‐2 for SL), which illustrated a greater efficiency of sheet erosion on longer slopes. Results from a principal component analysis, whose two first axes explained 60% of the data variance, suggested that sheet erosion is mainly controlled by rainfall characteristics (rainfall intensity and amount) and soil surface features (crusting and vegetation coverage). The contribution of RIF to sheet erosion was the lowest at high soil clay content (r = 0.26) and the highest at high crusting and bulk density (r = 0.22), cumulative rainfall amount in the season and associated rise in soil water table (r = 0.29). Such an explicit consideration of the role of scale on sediment yields and process domination by either in situ (soil and soil surface conditions) or ex situ (rainfall characteristics and antecedent rainfall) factors, is expected to contribute to process‐based modelling and erosion mitigation. Copyright © 2012 John Wiley & Sons, Ltd.
Proton Conducting Membranes Based on Poly(2,2′‐imidazole‐5,5′‐bibenzimidazole)
Authors: Guan Y. , Pu H. , Jin M. , Chang Z. , Modestov A. D.
Published: January 2012

Poly(2,2′‐imidazole‐5,5′‐bibenzimidazole) (PBI‐imi) was synthesized via the polycondensation between 3,3′,4,4′‐tetraaminobiphenyl and 4,5‐imidazole‐dicarboxylic acid. Effects of the reaction conditions on the intrinsic viscosity of the synthesized polymers were studied. The results show that the molecular weight of the polymers increases with increasing monomer concentration and reaction time, and then levels off. With higher reaction temperature, the molecular weight of the polymer is higher. With the additional imidazole group in the backbone, PBI‐imi shows improved phosphoric acid doping ability, as well as a little higher proton conductivity when compared with widely used poly[2,2′‐(m‐phenylene)‐5,5′‐bibenzimidazole] (PBI‐ph).Whereas, PBI‐imi and PBI‐ph have the similar chemical oxidation stability. PBI‐imi/3.0 H3PO4 composite membranes exhibit a proton conductivity as high as 10–4 S cm–1 at 150 °C under anhydrous condition. The temperature dependence of proton conductivity of acid doped PBI‐imi can be modeled by an Arrhenius equation.
Temperature Measurement and Distribution Inside Planar SOFC Stacks
Authors: Guan W. B. , Zhai H. J. , Jin L. , Xu C. , Wang W. G.
Published: January 2012

In this work, a kind of thin K‐type thermocouple and self‐developed CAS‐I sealant were used to assembly solid oxide fuel cell (SOFC) stacks and temperatures of unit cells inside a planar SOFC stack were measured. The open circuit voltage testing of the stack and characterization of the interface between sealant and components suggested excellent sealing effect by applying the developed method. The effect of discharging direct‐current on temperature and temperature distribution inside the designed SOFC stack was investigated. The results showed that the discharging current had a great impact and the gas flow rate had a slight impact on the temperatures of unit cells. Temperature distribution of unit cells inside the stack was much non‐uniform and there is a significant temperature difference between various components of the stack and heating environment. The relationship between temperatures and cell performance showed that the worse the cell performance, the higher the cell surface temperature. When the stack was discharged at a constant current and the temperature of cell surface was over 950 °C, the higher the temperature, the more drop the corresponding voltage.
INCORPORATING FINANCIAL PROTECTION INTO DECISION RULES FOR PUBLICLY FINANCED HEALTHCARE TREATMENTS
Authors: Smith Peter C.
Published: January 2012

Almost all health systems seek to offer some form of publicly financed healthcare insurance, and governments must therefore choose the size of the benefit package and the types of treatments to cover. Conventionally, the usual approach of economists has been to recommend choices on the basis of cost effectiveness of treatments, using metrics such as the ‘cost per quality adjusted life year’. However, this approach is based on the assumption of health maximization subject to a budget constraint and ignores the potential impact of any additional concern with protecting individuals from the financial consequences of a health shock. Furthermore, it does not take account of the possible availability of complementary privately funded health care. This paper develops a model in which risk‐averse individuals care about health but also place a value on protection from the financial consequences of rare but costly events. The paper shows how conventional cost‐effectiveness analysis can readily be augmented to take account of financial protection objectives. The results depend on whether or not there exists a market in complementary privately funded health care. They have important implications for the methodology adopted by health technology assessment agencies and for the broader design of publicly funded health systems. Copyright © 2012 John Wiley & Sons, Ltd.
Predicting event response in a nested catchment with generalized linear models and a distributed watershed model
Authors: Graeff T. , Zehe E. , Blume T. , Francke T. , Schröder B.
Published: January 2012

This study focuses on the prediction of event‐based runoff coefficients (an important descriptor of flood events) for nested catchments up to an area of 50 km² in the Eastern Ore Mountains. The four main objectives of the study are (i) the prediction of runoff coefficients with the statistical method of generalized linear models, (ii) the comparison of the results of the linear models with estimates of a distributed conceptual model, (iii) the comparison of the dynamics of observed soil moisture and simulated saturation deficit of the hydrological model and (iv) the analysis of the relationship between runoff coefficient and observed and simulated wetness.

Different predictor variables were selected to describe the runoff coefficient and were differentiated into variables describing the catchment's antecedent wetness and meteorological forcing. The best statistical model was estimated in a stepwise approach on the basis of hierarchical partitioning, an exhaustive search algorithm and model validation with jackknifing. We then applied the rainfall runoff model WaSiM ETH to predict the runoff processes for the two larger catchments. Locally measured small‐scale soil moisture (acquired at a scale of four to five magnitudes smaller than the catchment) was identified as one of the key predictor variables for the estimation of the runoff coefficient with the general linear model. It was found that the relationship betweenobserved and simulated (using WaSiM ETH) wetness is strongly hysteretic. The runoff coefficients derived from the rainfall runoff simulations systematically underestimate the observed values. Copyright © 2012 John Wiley & Sons, Ltd.
Increased physical activity is associated with enhanced development of peak bone mass in men: A five-year longitudinal study
Authors: Nilsson Martin , Ohlsson Claes , Odén Anders , Mellström Dan , Lorentzon Mattias
Published: January 2012

Data supporting physical activity guidelines to optimize bone development in men is sparse. Peak bone mass is believed to be important for the risk of osteoporosis later in life. The objective of this study was to determine if an increased amount of physical activity over a 5-year period was associated with increased bone mineral content (BMC), areal (aBMD) and volumetric (vBMD) bone mineral density, and a favorable development of cortical bone size in young adult men. The original 1068 young men, initially enrolled in the Gothenburg Osteoporosis and Obesity Determinants (GOOD) study, were invited to participate in the longitudinal study, and a total of 833 men (78%), 24.1 ± 0.6 years of age, were included in the 5-year follow-up. A standardized self-administered questionnaire was used to collect information about patterns of physical activity at both the baseline and 5-year follow-up visits. BMC and aBMD were measured using dual energy X-ray absorptiometry, whereas vBMD and bone geometry were measured by peripheral quantitative computed tomography. Increased physical activity between the baseline and follow-up visits was associated with a favorable development in BMC of the total body, and aBMD of the lumbar spine and total hip (p < 0.001), as well as with development of a larger cortex (cortical cross sectional area), and a denser trabecular bone of the tibia (p < 0.001). In conclusion, increased physical activity was related to an advantageous development of aBMD, trabecular vBMD and cortical bone size, indicating that exercise is important in optimizing peak bone mass in young men. © 2012 American Society for Bone and Mineral Research.
Genetic evidence that thyroid hormone is indispensable for prepubertal insulin-like growth factor–I expression and bone acquisition in mice
Authors: Xing Weirong , Govoni Kristen E , Donahue Leah Rae , Kesavan Chandrasekhar , Wergedal Jon , Long Carlin , Bassett JH Duncan , Gogakos Apostolos , Wojcicka Anna , Williams Graham R , Mohan Subburaman
Published: January 2012

Understanding how bone growth is regulated by hormonal and mechanical factors during early growth periods is important for optimizing the attainment of peak bone mass to prevent or postpone the occurrence of fragility fractures later in life. Using genetic mouse models that are deficient in thyroid hormone (TH) (Tshr−/− and Duox2−/−), growth hormone (GH) (Ghrhrlit/lit), or both (Tshr−/−; Ghrhrlit/lit), we demonstrate that there is an important period prior to puberty when the effects of GH are surprisingly small and TH plays a critical role in the regulation of skeletal growth. Daily administration of T3/T4 during days 5 to 14, the time when serum levels of T3 increase rapidly in mice, rescued the skeletal deficit in TH-deficient mice but not in mice lacking both TH and GH. However, treatment of double-mutant mice with both GH and T3/T4 rescued the bone density deficit. Increased body fat in the TH-deficient as well as TH/GH double-mutant mice was rescued by T3/T4 treatment during days 5 to 14. In vitro studies in osteoblasts revealed that T3 in the presence of TH receptor (TR) α1 bound to a TH response element in intron 1 of the IGF-I gene to stimulate transcription. In vivo studies using TRα and TRβ knockout mice revealed evidence for differential regulation of insulin-like growth factor (IGF)-I expression by the two receptors. Furthermore, blockade of IGF-I action partially inhibited the biological effects of TH, thus suggesting that both IGF-I–dependent and IGF-I–independent mechanisms contribute to TH effects on prepubertal bone acquisition. © 2012 American Society for Bone and Mineral Research.
Is inhibition process better described with MD(QM/MM) simulations? The case of urokinase type plasminogen activator inhibitors
Authors: Barbault Florent , Maurel François
Published: January 2012

Urokinase plasminogen activator (uPA) is an enzyme involved in cancer growth and metastasis. Therefore, the design of inhibitors of uPA is of high therapeutic value, and several chemical families have been explored, even if none has still emerged, emphasizing the need of a rationalized approach. This work represents a complete computational study of uPA complexed with five inhibitors, which present weak similarities. Molecular dynamics simulations in explicit solvent were conducted, and structural analyses, along with molecular mechanics (MM)/Poisson–Boltzmann surface area free energies estimations, yield precious structure–activity relationships of these inhibitors. Besides, we realized supplemental QM/MM computations that improved drastically the quality of our models providing original information on the hydrogen bonds and charge transfer effects, which are, most often, neglected in other studies. We suggest that these simulations and analyses could be reproduced for other systems involving protein/ligand molecular recognitions. © 2012 Wiley Periodicals, Inc. J Comput Chem, 2012
Cu2+ removal from aqueous solution by modified chitosan hydrogels
Authors: Liu Yi , Kang Yuru , Huang Dajian , Wang Aiqin
Published: January 2012

BACKGROUND: The adsorption of Cu2+ from aqueous solution using crosslinked chitosan hydrogels impregnated with Congo Red (CR) by ion‐imprint technology was systematically investigated with particular reference to the effects of contact time, pH, and initial concentration on adsorption.

RESULTS: The adsorption capacity of the crosslinked chitosan without impregnation was only 68.68 mg g−1 for Cu2+. However, the adsorption capacity increased from 77.42 (without imprint ion) to 84.54 mg g−1 (imprint ion content 0.5 mmol) after the chitosan was impregnated with a ratio of 1/12 of CR to chitosan. The as‐prepared adsorbents were found to be pH‐dependent and the process of adsorption agreed well with the Freundlich isotherm. The loaded adsorbents could be regenerated and reused without the appreciable loss of capacity.

CONCLUSION: Chitosan hydrogels impregnated with CR showed higher Cu2+ adsorption capacities compared with those prepared conventionally without imprint ion, and thus developed a good approach to increase Cu2+ adsorption efficiency in the treatment of waste‐water. Copyright © 2012 Society of Chemical Industry
Cardiac MRI of the fetal heart using a novel triggering method: Initial results in an animal model
Authors: Yamamura Jin , Kopp Inga , Frisch Michael , Fischer Roland , Valett Klaus , Hecher Kurt , Adam Gerhard , Wedegärtner Ulrike
Published: January 2012

Purpose:

To investigate MRI of the fetal heart by way of a novel triggering method with the use of an MR‐compatible cardiotocography (CTG) in an animal model.

Materials and Methods:

Fetal cardiac MRI was performed on four pregnant ewes on a 1.5 Tesla (T) MR system. A CTG was rendered MR compatible and its signal was used for the triggering of the fetal heart to perform cardiac cine MRI of the fetal heart with maternal free‐breathing with cine steady‐state free precession. The left ventricular volume and function were measured from the short‐axis (view). The image quality of anatomical structures was assessed.

Results:

All cardiac valves and the foramen ovale could be visualized. Myocardial contraction was depicted in cine sequences. The average blood volume at the end systole was 1.7 mL (SD ± 0.12). The average volume at the end diastole was 4.6 mL (± 0.4); thus the average stroke volumes of the left ventricle were 2.87 mL (± 0.31) with ejection fractions of 60.53% (± 4.17).

Conclusion:

The newly developed MR compatible CTG could be used as a tool for cardiac triggering method of the fetal heart. This novel device might help fetal cardiac MRI technology in the future. J. Magn. Reson. Imaging 2012;35:1071‐1076. © 2012 Wiley Periodicals, Inc.
Does the amplatzer septal occluder device alter ventricular contraction pattern? A ventricular motion analysis by MR tagging
Authors: Stern Heiko , Baurecht Hansjörg , Luechinger Roger , Schwaiger Markus , Hess John , Fratz Sohrab
Published: January 2012

Purpose:

To assess by cardiovascular magnetic resonance (CMR) and CMR tagging if the Amplatzer Septal Occluder affects right ventricular (RV) and left ventricular (LV) motion pattern.

Materials and Methods:

Sixteen consecutive patients with significant atrial septal defect (ASD) and nine consecutive patients with persistent foramen ovale (PFO) as controls were studied before and a median of 14 days after defect closure by an Amplatzer occluder. By CMR end‐diastolic (EDV) and end‐systolic (ESV) RV and LV volumes were determined. Aortic and pulmonary artery flow was measured for assessment of left‐to‐right shunt (Qp/Qs). By CMR tagging circumferential strain and radial shortening, maximal rotation and torsion were measured,

Results:

In ASD patients RV‐EDV and RV‐ESV decreased (P < 0.05). LV‐EDV and LV‐ESV increased after ASD closure (P < 0.005). Qp/Qs dropped from 1.8 to 1.0 (P < 0.001). PFO patients showed no ventricular volume change after PFO closure. In ASD patients circumferential strain and radial shortening and maximal rotation of the RV decreased by ASD closure (P < 0.01). In LV only maximal rotation at the base and apex decreased significantly (P < 0.05). Torsion remained constant. In PFO patients no tagging parameter changed after defect closure.

Conclusion:

The Amplatzer occluder itself does not change the ventricular contraction pattern. All volume and myocardial deformation changes were caused by ventricular loading shifts. J. Magn. Reson. Imaging 2012;35:949–956. © 2012 Wiley Periodicals, Inc.
Comparison of visceral adipose tissue quantification on water suppressed and nonwater‐suppressed MRI at 3.0 tesla
Authors: Zhou Anqi , Murillo Horacio , Cusi Kenneth , Peng Qi
Published: January 2012

Purpose:

To systematically evaluate and compare the performance of water‐saturated and nonwater‐saturated T1‐weighted 3.0 T magnetic resonance imaging (MRI) in the application of visceral adipose tissue (VAT) quantification.

Materials and Methods:

Forty‐five patients underwent abdomen MRI using two different sequences at 3.0 T: 1) a traditional T1‐weighted gradient echo sequence, and 2) the same sequence with water presaturation to enhance fat and nonfat contrast. VAT amounts from both water‐saturated and nonwater‐saturated images were quantified with a manual thresholding technique and an automated segmentation method to study quantification variability and consistency of the two imaging techniques.

Results:

Nonwater‐saturated MRI had significantly larger coefficient of variation than water‐saturated MRI in the imaging reproducibility study based on 112 slices from seven subjects (11.4% vs. 2.5%, P < 0.0001). VAT volumes measured from the nonwater‐saturation MRI sequence had significantly higher variability than those from water‐saturation images even when using a manual quantification method based on images from 38 subjects (1.76% vs. 1.08%, P < 0.001). In addition, the VAT volume amounts from nonwater‐saturation images and water‐saturated images quantified with the automatic and manual quantification methods were statistically consistent.

Conclusion:

Water‐saturated MRI sequences at 3.0 T for VAT quantification improve reproducibility and decrease variability compared with nonwater saturated sequences, especially with the use of automatic quantification methods. J. Magn. Reson. Imaging 2012;35:1445–1452. © 2012 Wiley Periodicals, Inc.
Detection and localization of prostate cancer with the targeted biopsy strategy based on ADC Map: A prospective large‐scale cohort study
Authors: Watanabe Yuji , Terai Akito , Araki Tohru , Nagayama Masako , Okumura Akira , Amoh Yoshiki , Ishimori Takayoshi , Ishibashi Mana , Nakashita Satoru , Dodo Yoshihiro
Published: January 2012

Purpose:

To investigate the usefulness of targeted biopsy strategy based on apparent diffusion coefficient (ADC) maps in the detection and localization of prostate cancer.

Materials and Methods:

Institutional review board approval and informed consent from all participants were obtained. This study included 1448 consecutive patients suspected of having prostate cancer based on PSA level, who were divided into two groups: Group A included 890 patients with low‐ADC lesions who underwent targeted and systematic biopsies; Group B included 558 patients with no low‐ADC lesions who underwent only systematic biopsies. The cancer detection rates (CDR) of each group, positive predictive value (PPV), and negative predictive value (NPV) of ADC maps were calculated.

Results:

The CDR was 70.1% for Group A, higher than those for overall patients (48.1%) and for Group B (13.1%) with significant difference (P < 0.001). In the serum, PSA range from 4 to 20 ng/mL, the CDR was higher for the Group A than for the Group B and overall patients with significant differences. PPV and NPV of MR findings were 70.1% and 86.9%, respectively. Especially, the PPV of the MR findings for the anterior portion was as high as 90.1%. Among the false negatives of MR findings, Gleason score proved 6 or smaller in 79.5%, and positive core number was merely one or two in 80.8%.

Conclusion:

The targeted biopsy strategy based on ADC maps can be useful in the detection and localization of prostate cancer with high PPV. J. Magn. Reson. Imaging 2012;35:1414–1421. © 2012 Wiley Periodicals, Inc.
Osteogenic and chondrogenic potential of biomembrane cells from the PMMA‐segmental defect rat model
Authors: Gruber Helen E. , Riley Frank E. , Hoelscher Gretchen L. , Bayoumi Essraa M. , Ingram Jane A. , Ramp Warren K. , Bosse Michael J. , Kellam James F.
Published: January 2012

A layer of cells (the “biomembrane”) has been identified in large segmental defects between bone and surgically placed methacrylate spacers or antibiotic‐impregnated cement beads. We hypothesize that this contains a pluripotent stem cell population with potential valuable applications in orthopedic tissue engineering. Objectives using biomembranes harvested from rat segmental defects were to: (1) Culture biomembrane cells in specialized media to direct progenitor cells along bone or cartilage cell differentiation lineages; (2) evaluate harvested biomembranes for mesenchymal stem cell markers, and (3) define relevant gene expression patterns in harvested biomembranes using microarray analysis. Culture in osteogenic media produced mineralized nodules; culture in chondrogenic media produced masses containing chondroitin sulfate/sulfated proteoglycans. Molecular analysis of biomembrane cells versus control periosteum showed significant upregulation of key genes functioning in mesenchymal stem cell differentiation, development, maintenance, and proliferation. Results identified significant upregulation of WNT receptor signaling pathway genes and significant upregulation of BMP signaling pathway genes. Findings confirm that the biomembrane has a pluripotent stem cell population. The ability to heal large bone defects is clinically challenging, and novel tissue engineering uses of the biomembrane hold great promise in treating non‐unions, open fractures with large bone loss and/or infections, and defects associated with tumor resection. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1198–1212, 2012
Effect of soy flour addition and heat‐processing method on nutritional quality and consumer acceptability of cassava complementary porridges
Authors: Muoki Penina N , de Kock Henriëtte L , Emmambux Mohammad Naushad
Published: January 2012

BACKGROUND: The nutritional quality of cassava complementary porridge was improved through extrusion cooking and compositing with either defatted or full fat soy flour (65:35 w/w), and product acceptability by mothers with children of the target population was evaluated.

RESULTS: The protein digestibility‐corrected amino acid score (PDCAAS) of extrusion‐ and conventionally cooked composite porridges was within the recommendations for complementary foods. The kinetics of starch digestibility showed that all porridges had a rapid rate of starch digestibility, but the rate was lower when defatted soy flour was added and lowest when full fat soy flour was added. The formation of amylase‐lipid complexes as shown by X‐ray diffraction and differential scanning calorimetry can be attributed to the lower digestibility of extrusion‐cooked porridge with full fat soy flour. If fed thrice per day, extrusion‐cooked porridge with defatted or full fat soy flour would meet the energy, protein and available lysine requirements of a child aged 6–8 months receiving low or average nutrients from breast milk. All porridges were well received by Mozambican mothers who use cassava as a staple food. The mean scores for sensory liking of all porridges were 3 and above on a five‐point hedonic scale.

CONCLUSION: Extrusion‐cooked cassava/soy flour porridges have good potential for use as high‐energy/high‐protein complementary foods and have acceptable sensory properties. Copyright © 2012 Society of Chemical Industry
Antimicrobial activity of food‐compatible plant extracts and chitosan against naturally occurring micro‐organisms in tomato juice
Authors: Giner Manuel J , Vegara Salud , Funes Lorena , Martí Nuria , Saura Domingo , Micol Vicente , Valero Manuel
Published: January 2012

BACKGROUND: Chitosan (AC) and five hydroalcoholic extracts from Lithospermum erythrorhizon (SE), Rheum palmatum (RE), Thymus vulgaris (AT), Lippia citriodora (PLX) and a mixture of Rosmarinus officinalis, Salvia lavandulifolia and Thymus mastichina (LA) were tested for antimicrobial activity against bacteria, yeasts and filamentous fungi using two broth dilution methods. The effects of adding single extracts on naturally occurring micro‐organisms and sensory qualities of raw tomato juice were also evaluated.

RESULTS: SE extract exhibited the strongest activity, with minimum inhibitory concentrations (MICs) of 100–400 µg mL−1 for Gram‐positive and 1600–3200 µg mL−1 for Gram‐negative bacteria. Enterobacter aerogenes showed the greatest susceptibility to AC (MIC 1600 µg mL−1). Lethal effects of extracts and AC were achieved at a minimum bactericidal concentration (MBC)/MIC ratio of 2 in 88% of assays. SE and RE extracts and AC also exhibited antifungal effect against yeasts, but they had no activity on filamentous fungi. Control and 100 mg L−1 SE‐added tomato juices did not differ in acceptance, but this SE concentration was not effective in the control of microbial load throughout cold storage.

CONCLUSION: Results confirm the antimicrobial potential of the plant extracts, but additional research is needed until the agents responsible for the activities have been determined in order to use them as natural constituents of multiple‐barrier food preservation systems. Copyright © 2012 Society of Chemical Industry
Mechanistic aspects of ligand substitution on [(H2O)(tap)2RuORu(tap)2(H2O)]2+ ion {tap = 2‐(m‐tolylazo)pyridine} by some amino acids in aqueous medium at physiological pH
Authors: Mandal Arup , Mondal Subala , Karmakar Parnajyoti , Mallick Subhasis , Bera Biplab K. , Ghosh Alak K.
Published: January 2012

The interaction of the title complex with selected amino acids such as glycine (L1H), l‐valine (L2H), and l‐leucine (L3H) has been studied spectrophotometrically in aqueous medium as a function of [substrate complex], [ligand], and temperature. The reaction has been monitored at 600 nm, where the spectral difference between the reactant and product is maximum. At pH 7.4, the reaction has been found to proceed via two distinct consecutive steps, i.e., it shows a nonlinear dependence on the concentration of ligands: The first process is [ligand] dependent, but the second step is [ligand] independent. The rate constants for the processes are k1∼10−3 s−1 and k2∼10−4 s −1. The activation parameters were calculated from Eyring plots. Based on the kinetic and activation parameters, an associative interchange mechanism is proposed for the interaction processes. From the temperature dependence of the outer sphere association equilibrium constant, the thermodynamic parameters were also calculated, which gives a negative Δ Go value for both the steps at all temperatures studied, supporting the spontaneous formation of an outer sphere association complex. The product of the reaction has been characterized with the help of conductance measurement, IR, NMR, and ESI‐mass spectroscopic analysis. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 612–623, 2012
Sensitivity enhancement of remotely coupled NMR detectors using wirelessly powered parametric amplification
Authors: Qian Chunqi , Murphy‐Boesch Joseph , Dodd Stephen , Koretsky Alan
Published: January 2012

A completely wireless detection coil with an integrated parametric amplifier has been constructed to provide local amplification and transmission of MR signals. The sample coil is one element of a parametric amplifier using a zero‐bias diode that mixes the weak MR signal with a strong pump signal that is obtained from an inductively coupled external loop. The NMR sample coil develops current gain via reduction in the effective coil resistance. Higher gain can be obtained by adjusting the level of the pumping power closer to the oscillation threshold, but the gain is ultimately constrained by the bandwidth requirement of MRI experiments. A feasibility study here shows that on a NaCl/D2O phantom, 23Na signals with 20 dB of gain can be readily obtained with a concomitant bandwidth of 144 kHz. This gain is high enough that the integrated coil with parametric amplifier, which is coupled inductively to external loops, can provide sensitivity approaching that of direct wire connection. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.
Flexible transceiver array for ultrahigh field human MR imaging
Authors: Wu Bing , Zhang Xiaoliang , Wang Chunsheng , Li Ye , Pang Yong , Lu Jonathan , Xu Duan , Majumdar Sharmila , Nelson Sarah J. , Vigneron Daniel B.
Published: January 2012

A flexible transceiver array, capable of multiple‐purpose imaging applications in vivo at ultrahigh magnetic fields was designed, implemented and tested on a 7 T MR scanner. By alternately placing coil elements with primary and secondary harmonics, improved decoupling among coil elements was accomplished without requiring decoupling circuitry between resonant elements, which is commonly required in high‐frequency transceiver arrays to achieve sufficient element‐isolation during radiofrequency excitation. This flexible array design is capable of maintaining the required decoupling among resonant elements in different array size and geometry and is scalable in coil size and number of resonant elements (i.e., number of channels), yielding improved filling factors for various body parts with different geometry and size. To investigate design feasibility, flexibility, and array performance, a multichannel, 16‐element transceiver array was designed and constructed, and in vivo images of the human head, knee, and hand were acquired using a whole‐body 7 T MR system. Seven Tesla parallel imaging with generalized autocalibrating partially parallel acquisitions (GRAPPA) performed using this flexible transceiver array was also presented. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.
Comparison of two ultrashort echo time sequences for the quantification of T1 within phantom and human Achilles tendon at 3 T
Authors: Wright Peter , Jellus Vladimir , McGonagle Dennis , Robson Matthew , Ridgeway John , Hodgson Richard
Published: January 2012

Ultrashort echo time (UTE) techniques enable direct imaging of musculoskeletal tissues with short T2 allowing measurement of T1 relaxation times. This article presents comparison of optimized 3D variable flip angle UTE (VFA‐UTE) and 2D saturation recovery UTE (SR‐UTE) sequences to quantify T1 in agar phantoms and human Achilles tendon. Achilles tendon T1 values for asymptomatic volunteers were compared to Achilles tendon T1 values calculated from patients with clinical diagnoses of spondyloarthritis (SpA) and Achilles tendinopathy using an optimized VFA‐UTE sequence. T1 values from phantom data for VFA‐ and SR‐UTE compare well against calculated T1 values from an assumed gold standard inversion recovery spin echo sequence. Mean T1 values in asymptomatic Achilles tendon were found to be 725 ± 42 ms and 698 ± 54 ms for SR‐ and VFA‐UTE, respectively. The patient group mean T1 value for Achilles tendon was found to be 957 ± 173 ms (P < 0.05) using an optimized VFA‐UTE sequence with pulse repetition time of 6 ms and flip angles 4, 19, and 24°, taking a total 9 min acquisition time. The VFA‐UTE technique appears clinically feasible for quantifying T1 in Achilles tendon. T1 measurements offer potential for detecting changes in Achilles tendon due to SpA without need for intravenous contrast agents. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.
On the fluid‐tissue contrast behavior of high‐resolution steady‐state sequences
Authors: Bieri Oliver , Ganter Carl , Scheffler Klaus
Published: January 2012

In general, MR image contrast is expected to be resolution independent, but a pronounced loss of contrast is observed between fluids and tissues with contemporary musculoskeletal protocols (typical inplane resolution << 1 mm) using nonbalanced steady‐state free precession, such as double echo steady state. For nonbalanced steady‐state free precession, diffusion sensitivity increases with increasing spoiler moments which increase with decreasing voxel size, suggesting diffusion damping as the major cause for the observed contrast variation. This is confirmed by simulations and measurements indicating that for fluids, diffusion effects become apparent already for resolutions Δx < 1 mm, whereas tissues typically require Δx < 200 μm. Gradient spoiling, however, is generically not minimized but frequently applied along the readout direction. For anisotropic steady‐state free precession scans, the loss of contrast between fluids and tissues from diffusion can thus be minimized by simply moving the spoiler gradients to the lowest resolution direction. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.
Mitochondria of trained skeletal muscle are protected from deleterious effects of statins
Authors: Bouitbir Jamal , Daussin Frédéric , Charles Anne‐Laure , Rasseneur Laurence , Dufour Stéphane , Richard Ruddy , Piquard François , Geny Bernard , Zoll Joffrey
Published: January 2012

Introduction: Statins are associated with adverse skeletal muscle effects. Our objective was to determine if muscular adaptations following exercise training prevented deleterious effects of atorvastatin in glycolytic skeletal muscle. Methods: Twenty rats were divided into 2 groups: a control group (n = 10; Cont) and a 10 days of training group (n = 10; Training). Using the permeabilized fibers technique, we explored mitochondrial function. Results: Exercise training increased Vmax and H2O2 production without altering the free radical leak, and mRNA expression of SOD2 and Cox1 were higher in trained muscle. In the Cont group, atorvastatin exposure increased H2O2 production and decreased skeletal muscle Vmax. The decreased Vmax effect of atorvastatin was dose dependent. Interestingly, the half‐maximal inhibitory concentration (IC50) was higher in the Training group. H2O2 production increased in trained muscle after atorvastatin exposure. Conclusions: These results suggest that improvements in mitochondrial respiratory and antioxidant capacities following endurance training protected mitochondria against statin exposure. Muscle Nerve 46: 367–373, 2012
Hepatoma‐derived growth factor regulates breast cancer cell invasion by modulating epithelial–mesenchymal transition
Authors: Chen San‐Cher , Kung Mei‐Lang , Hu Tsung‐Hui , Chen Hsuan‐Yu , Wu Jian‐Ching , Kuo Hsiao‐Mei , Tsai Han‐En , Lin Yu‐Wei , Wen Zhi‐Hong , Liu Jong‐Kang , Yeh Ming‐Hsin , Tai Ming‐Hong
Published: January 2012

Hepatoma‐derived growth factor (HDGF) participates in tumourigenesis but its role in breast cancer is unclear. We set out to elucidate the expression profile and function of HDGF during breast carcinogenesis. Immunoblot and immunohistochemical studies revealed elevated HDGF expression in human breast cancer cell lines and tissues. Nuclear HDGF labelling index was positively correlated with tumour grade, stage and proliferation index, but negatively correlated with survival rate in breast cancer patients. HDGF over‐expression was associated with lymph node metastasis and represented an independent prognostic factor for tumour recurrence. Gene transfer studies were performed to elucidate the influence of cellular HDGF level on the malignant behaviour and epithelial‐mesenchymal transition (EMT) of breast cancer cells. Adenovirus‐mediated HDGF over‐expression stimulated the invasiveness and colony formation of MCF‐7 cells. Moreover, HDGF over‐expression promoted breast cancer cell EMT by E‐cadherin down‐regulation and vimentin up‐regulation. Conversely, HDGF knockdown by RNA interference in MDA‐MB‐231 cells attenuated the malignant behaviour and elicited EMT reversal by enhancing E‐cadherin expression while depleting vimentin expression. Because HDGF is a secreted protein, we evaluated the cellular function of recombinant HDGF and found that exogenously supplied HDGF enhanced the invasiveness of breast cancer cells by down‐regulating E‐cadherin and up‐regulating vimentin at transcriptional and translational levels. In contrast, blockade of HDGF secretion with an HDGF antibody inhibited the malignant behaviours and EMT. Finally, exogenous HDGF partially reversed benzyl isothiocyanate (BITC)‐induced EMT suppression. HDGF over‐expression may exert a prognostic role for tumour metastasis and recurrence in breast cancer by modulating EMT. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Effect of carbon‐based nanoparticles on the cure characteristics and network structure of styrene–butadiene rubber vulcanizate
Authors: Saatchi Mohammad Mahdi , Shojaei Akbar
Published: January 2012

The network structure of styrene–butadiene rubber (SBR) in the presence of carbon black (CB) with two different structures and multi‐walled carbon nanotubes (MWCNTs) was investigated. Swelling behaviour, tensile properties at various strain rates and cure kinetics were characterized. Experimental data were analysed using the Flory–Rehner model as well as the tube model theory. It is found that the network structure of CB‐filled SBR follows a three‐phase composite model including rigid particles, semi‐rigid bound rubber and matrix rubber. This bound rubber is postulated to be critical for the mechanical and deformational properties, development of crosslinking density in matrix rubber and polymer–filler interaction. For MWCNT‐filled SBR, the bound rubber does not show a substantial contribution to the network structure and mechanical performance, and these properties are greatly dominated by the higher aspect ratio and polymer–filler interaction. Additionally it is deduced that the crosslinking density of matrix rubber increases on incorporation of the fillers compared to unfilled matrix rubber. Copyright © 2012 Society of Chemical Industry
Neglected markers: Altered serum proteome in murine models of disease
Authors: Gianazza Elisabetta , Vegeto Elisabetta , Eberini Ivano , Sensi Cristina , Miller Ingrid
Published: January 2012

More than a decade ago our groups pioneered the analysis of serum proteins of laboratory animals with up‐to‐date proteomic techniques. We were, and still are, convinced that conforming animal procedures to the minimally invasive approaches typical of clinical biochemistry focuses attention on the actual conditions under which any finding arrived at on animal models of disease may eventually be applied to human patients for screening/diagnosis. We are also convinced that, besides the proteins present in trace level as a result of tissue leakage during disorders affecting specific peripheral organs, changes in the concentration of some of the major serum proteins as part of an acute‐phase response may be taken as biological end‐points during a number of experimental procedures. When reviewing literature data about proteomic investigations on plasma or serum of mice, we realized that not much work has been done in the direction we favor. In addition, we noticed that sometimes information about serum proteome has been coarsely treated and in a few cases even misunderstood/misused. In the following, we present current findings on serum/plasma proteome of the laboratory mouse not only under control conditions and during an experimentally induced acute‐phase reaction, but also in a number of models of disease, mainly related to cancer and to metabolic disorders.
To label or not to label: Applications of quantitative proteomics in neuroscience research
Authors: Filiou Michaela D. , Martins‐de‐Souza Daniel , Guest Paul C. , Bahn Sabine , Turck Christoph W.
Published: January 2012

Proteomics has provided researchers with a sophisticated toolbox of labeling‐based and label‐free quantitative methods. These are now being applied in neuroscience research where they have already contributed to the elucidation of fundamental mechanisms and the discovery of candidate biomarkers. In this review, we evaluate and compare labeling‐based and label‐free quantitative proteomic techniques for applications in neuroscience research. We discuss the considerations required for the analysis of brain and central nervous system specimens, the experimental design of quantitative proteomic workflows as well as the feasibility, advantages, and disadvantages of the available techniques for neuroscience‐oriented questions. Furthermore, we assess the use of labeled standards as internal controls for comparative studies in humans and review applications of labeling‐based and label‐free mass spectrometry approaches in relevant model organisms and human subjects. Providing a comprehensive guide of feasible and meaningful quantitative proteomic methodologies for neuroscience research is crucial not only for overcoming current limitations but also for gaining useful insights into brain function and translating proteomics from bench to bedside.
Proteomic characterization of adipose tissue constituents, a necessary step for understanding adipose tissue complexity
Authors: Peinado Juan R. , Pardo María , de la Rosa Olga , Malagón Maria M.
Published: January 2012

The original concept of adipose tissue as an inert storage depot for the excess of energy has evolved over the last years and it is now considered as one of the most important organs regulating body homeostasis. This conceptual change has been supported by the demonstration that adipose tissue serves as a major endocrine organ, producing a wide variety of bioactive molecules, collectively termed adipokines, with endocrine, paracrine and autocrine activities. Adipose tissue is indeed a complex organ wherein mature adipocytes coexist with the various cell types comprising the stromal‐vascular fraction (SVF), including preadipocytes, adipose‐derived stem cells, perivascular cells, and blood cells. It is known that not only mature adipocytes but also the components of SVF produce adipokines. Furthermore, adipokine production, proliferative and metabolic activities and response to regulatory signals (i.e. insulin, catecholamines) differ between the different fat depots, which have been proposed to underlie their distinct association to specific diseases. Herein, we discuss the recent proteomic studies on adipose tissue focused on the analysis of the separate cellular components and their secretory products, with the aim of identifying the basic features and the contribution of each component to different adipose tissue‐associated pathologies.
Post‐genomics of bone metabolic dysfunctions and neoplasias
Authors: Bernardini Giulia , Braconi Daniela , Spreafico Adriano , Santucci Annalisa
Published: January 2012

Post‐genomic research on osteoblastic and osteoclastic cells, in contrast to that on many other cell types, has only been undertaken recently. Nevertheless, important information has been gained from these investigations on the mechanisms involved in osteoblast differentiation and on markers relevant for tissue regeneration and therapeutic validation of drugs, hormones and growth factors. These protein indicators may also have a diagnostic and prognostic value for bone dysfunctions and tumors. Some reviews have already focused on the application of transcriptomics and/or proteomics for exploring skeletal biology and related disorders. The main goal of the present review is to systematically summarize the most relevant post‐genomic studies on various metabolic bone diseases (osteoporosis, Paget's disease and osteonecrosis), neoplasias (osteosarcoma) and metabolic conditions that indirectly affect bone tissue, such as alkaptonuria.
Affinity‐based proteomic profiling: Problems and achievements
Authors: Medvedev Alexei , Kopylov Arthur , Buneeva Olga , Zgoda Victor , Archakov Alexander
Published: January 2012

Affinity chromatography becomes a more and more popular method used in proteomic studies for separation of various groups of proteins (subproteomes). The review highlights the role of affinity chromatography fractionation for proteomic profiling of the most of intensively studied groups of proteins including cyclic nucleotide‐binding proteins, protein kinases (kinomes), phosphoproteins, glycoproteins, ubiquitinated proteins. Special attention is paid to the use of affinity chromatography for the characterization of small‐molecule protein targets. The latter is especially important for the elucidation of direct protein targets of potential drug substances for evaluation of their possible side‐effects or additional pharmacological application.
Mass spectrometry‐based proteomics strategies for protease cleavage site identification
Authors: van den Berg Bart H. J. , Tholey Andreas
Published: January 2012

Protease‐catalyzed hydrolysis of peptide bonds is one of the most pivotal post‐translational modifications fulfilling manifold functions in the regulation of cellular processes. Therefore, dysregulation of proteolytic reactions plays a central role in many pathophysiological events. For this reason, understanding the molecular mechanisms in proteolytic reactions, in particular the knowledge of proteases involved in complex processes, expression levels and activity of protease and knowledge of the targeted substrates are an indispensable prerequisite for targeted drug development. The present review focuses on mass spectrometry‐based proteomic methods for the analysis of protease cleavage sites, including the identification of the hydrolyzed bonds as well as of the surrounding sequence. Peptide‐ and protein‐centric approaches and bioinformatic tools for experimental data interpretation will be presented and the major advantages and drawbacks of the different approaches will be addressed. The recent applications of these approaches for the analysis of biological function of different protease classes and potential future directions will be discussed.