bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of amylopectin structure and physicochemical properties in rice endosperm starch of mutant lines derived from Malaysian rice cultivar MR219
Authors: Mar Nyo Nyo , Umemoto Takayuki , Ismail Maznah , Abdullah Siti Nor Akma , Maziah Mahmood
Published: July 2012

BACKGROUND: Characterization of starch properties and functionality can apply breeding program selection for desirable traits such as eating, cooking and processing qualities to meet consumer preference. Low amylose content is generally preferred in Malaysia because of cohesive, tender and glossy cooked rice. Rice high in short‐chain amylopectin has a lower transition temperature of starch gelatinization. In the continuing search for improved starch quality in rice cultivars a study was carried out with new mutant lines MR219‐4 and MR219‐9, derived from MR219.

RESULTS: MR219 and its mutant lines contain L‐type amylopectin, being high in amylopectin of intermediate chain length with degree of polymerization 12‐21. The apparent amylose content (AAC) in MR219‐4 had lower AAC value (19.2%) compared to other lines. A strongly negative correlation was found between chain‐length fraction of amylopectin and transition temperatures—onset temperature peak temperature, and conclusion temperature (0.992, 0.958, 0.950; P < 0.01)—with fraction b1 (fb1), respectively.

CONCLUSION: The Malaysian lines studied contain L‐type amylopectin and offer a better understanding of grain quality improvement in terms of starch properties and functionality. This information will be directly applicable to select for desirable traits in future breeding programs. Copyright © 2012 Society of Chemical Industry
A simple gas chromatography method for the analysis of monoethanolamine in air
Authors: Gerster Fabian Melchior , Hopf Nancy Brenna , Huynh Cong Khanh , Plateel Grégory , Charrière Nicole , Vernez David
Published: July 2012

A simple method determining airborne monoethanolamine has been developed. Monoethanolamine determination has traditionally been difficult due to analytical separation problems. Even in recent sophisticated methods, this difficulty remains as the major issue often resulting in time‐consuming sample preparations. Impregnated glass fiber filters were used for sampling. Desorption of monoethanolamine was followed by capillary GC analysis and nitrogen phosphorous selective detection. Separation was achieved using a specific column for monoethanolamines (35% diphenyl and 65% dimethyl polysiloxane). The internal standard was quinoline. Derivatization steps were not needed. The calibration range was 0.5–80 μg/mL with a good correlation (R2 = 0.996). Averaged overall precisions and accuracies were 4.8% and –7.8% for intraday (n = 30), and 10.5% and –5.9% for interday (n = 72). Mean recovery from spiked filters was 92.8% for the intraday variation, and 94.1% for the interday variation. Monoethanolamine on stored spiked filters was stable for at least 4 weeks at 5°C. This newly developed method was used among professional cleaners and air concentrations (n = 4) were 0.42 and 0.17 mg/m3 for personal and 0.23 and 0.43 mg/m3 for stationary measurements. The monoethanolamine air concentration method described here was simple, sensitive, and convenient both in terms of sampling and analytical analysis.
Dispersive liquid–liquid microextraction of organophosphorous pesticides using nonhalogenated solvents
Authors: Cristina Henriques Alves Andreia , Margarida Pontes Boavida Gonçalves Maria , Manuel Serrano Bernardo Maria , Simões Mendes Benilde
Published: July 2012

Dispersive liquid–liquid microextraction (DLLME) combined with gas chromatography and mass spectrometry (GC‐MS) was applied to the determination of five organophosphorous pesticides (OPPs) in water samples. The analytes included in this study were prophos, diazinon, chlorpyrifos methyl, fenchlorphos, and chlorpyrifos. The use of nonhalogenated solvents (cyclohexane, heptane, and octane) as extraction solvents was investigated using acetone, acetonitrile, or methanol, as dispersion solvents. The combination of less polar dispersion solvents (1‐propanol and 2‐propanol) and nonhalogenated extraction solvents was also studied in dispersive liquid–liquid microextraction for the first time. Several experimental conditions were tested (nature and volume of extraction solvents, nature and volume of dispersion solvents, salting‐out effect) and the corresponding enrichment factors and recoveries were evaluated. The best microextraction condition was obtained using 50 μL of cyclohexane and 0.3 mL of 1‐propanol. The detection and quantification limits were in the low ppt range, with values between 3.3–8.0 ng/L and 11.0–26.6 ng/L, respectively. Relative standard deviations were between 6.6 and 13.1% for a fortification level of 500 ng/L. At the same fortification level, the relative recoveries (RR) of Alvito's dam water, Judeu's river water, and well water samples were in the range of 50.3–97.1%.
Ultrasound‐assisted extraction, HPLC analysis, and antioxidant activity of polyphenols from unripe apple
Authors: Yue Tianli , Shao Dongyan , Yuan Yahong , Wang Zhouli , Qiang Chunyan
Published: July 2012

The polyphenols were extracted from the unripe apple assisted by a highly efficient and simple method of the ultrasound. Response surface methodology was used to investigate the effects of processing parameters, including ultrasound power, extraction time, temperature, and ethanol concentration on total polyphenols yield and polyphenols composition was analyzed by HPLC. Antioxidant activity of the polyphenols was evaluated as 2, 2‐diphenyl‐1‐picrylhydracyl scavenging activity and inhibition activity of lipid peroxidation. The results showed that 10–100 times higher total polyphenols yield was obtained from the unripe apple than those from the reported apple pomace. The optimum extraction conditions were ultrasonic power of 519.39 W, extraction time of 30 min, extraction temperature 50°C, ethanol concentration of 50% gave the total polyphenols yield of 13.26 ± 0.56 mg GAE/g. HPLC analysis indicated that (−)‐epicatechin, procyanidin B2, chlorogenic acid, and procyanidin B1 were the predominant polyphenols in unripe apple, which contributed to the higher antioxidant activity to 2, 2‐diphenyl‐1‐picrylhydracyl of unripe apple polyphenols than other apple polyphenols. The extracted polyphenols had higher ability to inhibit lipid peroxidation than butylated hydroxy toluene, which demonstrated that the unripe apple polyphenols have the potential to be used as a substitute of some synthetic antioxidants.
Application of ultrahigh‐performance liquid chromatography coupled with mass spectrometry for analysis of lignans and quality control of Fructus Schisandrae chinensis
Authors: Zhang Wei‐Dong , Wang Qing , Wang Ying , Wang Xiao‐Juan , Pu Jian‐Xin , Gu Yi , Wang Rong
Published: July 2012

Lignans in the drug Fructus Schisandrae chinensis (FSC) exhibit potent biological activities such as antihepatotoxic, antiasthmatic, and antigastric ulcer. An ultrahigh‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry method has been developed to evaluate the quality of FSC through simultaneous qualitative and quantitative analysis of 15 lignans, including schizandrin A, B, and C; schizandrol A and B; gomisin B, C, D, E, G, H, J, and N; tigloylgomisin H; and angeloylgomisin H. The compounds were separated on a Zorbax Eclipse Plus C18 (2.1 × 100 mm, 1.8 μm) column with a gradient elution of acetonitrile and 0.1% formic acid. Lignans were identified through their retention times, accurate mass data, and characteristic ions by comparison with a reference substance. All calibration curves showed perfect linear regression (r2 > 0.99) within the test range. The limits of detection and quantitation fell in the ranges of 0.1–4 ng/mL for all the analytes with an injection of 10 μL. Good results were obtained with respect to repeatability (relative standard deviation <4.6%) and recovery (85.58–105.82%). Meanwhile, the entire sample analysis time was less than 10 min. This developed method provided a new basis for the overall assessment of the quality of FSC.
Effects of physicochemical properties of carotenoids on their bioaccessibility, intestinal cell uptake, and blood and tissue concentrations
Authors: Sy Charlotte , Gleize Beatrice , Dangles Olivier , Landrier Jean‐François , Veyrat Catherine Caris , Borel Patrick
Published: July 2012

Scope

Carotenoid bioavailability is affected by numerous factors. Our aim was to assess the involvement of known carotenoid physicochemical properties (e.g., hydrophobicity, van der Waals volume,…) on the transport of the main dietary carotenoids (β‐carotene, lycopene, lutein, and astaxanthin, from their food matrix to their main storage tissues.

Methods and results

We used four complementary models: synthetic mixed micelles, an in vitro digestion procedure, Caco‐2 cell monolayers, and a gavage experiment in rats. The efficiency with which pure carotenoids were incorporated into synthetic mixed micelles was related to their melting points (r = 0.99, p = 0.015). The efficiency with which pure carotenoids were transferred from dietary triglycerides into mixed micelles was related to carotenoid hydrophobicity (r = −1, p = 0.005). There was no relationship between the carotenoid physicochemical properties studied and their uptake efficiency by Caco‐2. The postprandial plasma carotenoid response to carotenoid gavage was related to carotenoid hydrophobicity (r = −0.99, p = 0.006). Carotenoid adipose tissue response was not related to the carotenoid physicochemical properties studied.

Conclusion

Thus, carotenoid hydrophobicity is important for bioaccessibility and postprandial blood response of carotenoids. In contrast, the carotenoid physicochemical properties studied are apparently not strong determinants of carotenoid uptake by enterocytes and adipose tissue.
Dimethyl sulfoxide (DMSO) as a potential contrast agent for brain tumors
Authors: Delgado‐Goñi T. , Martín‐Sitjar J. , Simões R. V. , Acosta M. , Lope‐Piedrafita S. , Arús C.
Published: July 2012

Dimethyl sulfoxide (DMSO) is commonly used in preclinical studies of animal models of high‐grade glioma as a solvent for chemotherapeutic agents. A strong DMSO signal was detected by single‐voxel MRS in the brain of three C57BL/6 control mice during a pilot study of DMSO tolerance after intragastric administration. This led us to investigate the accumulation and wash‐out kinetics of DMSO in both normal brain parenchyma (n = 3 control mice) by single‐voxel MRS, and in 12 GL261 glioblastomas (GBMs) by single‐voxel MRS (n = 3) and MRSI (n = 9). DMSO accumulated differently in each tissue type, reaching its highest concentration in tumors: 6.18 ± 0.85 µmol/g water, 1.5‐fold higher than in control mouse brain (p < 0.05). A faster wash‐out was detected in normal brain parenchyma with respect to GBM tissue: half‐lives of 2.06 ± 0.58 and 4.57 ± 1.15 h, respectively. MRSI maps of time‐course DMSO changes revealed clear hotspots of differential spatial accumulation in GL261 tumors. Additional MRSI studies with four mice bearing oligodendrogliomas (ODs) revealed similar results as in GBM tumors. The lack of T1 contrast enhancement post‐gadolinium (gadopentetate dimeglumine, Gd‐DTPA) in control mouse brain and mice with ODs suggested that DMSO was fully able to cross the intact blood–brain barrier in both normal brain parenchyma and in low‐grade tumors. Our results indicate a potential role for DMSO as a contrast agent for brain tumor detection, even in those tumors ‘invisible’ to standard gadolinium‐enhanced MRI, and possibly for monitoring heterogeneities associated with progression or with therapeutic response. Copyright © 2012 John Wiley & Sons, Ltd.
On the optimization of flux limiter schemes for hyperbolic conservation laws
Authors: Breuß Michael , Dietrich Dominik
Published: July 2012

A classic strategy to obtain high‐quality discretizations of hyperbolic partial differential equations is to use flux limiter (FL) functions for blending two types of approximations: a monotone first‐order scheme that deals with discontinuous solution features and a higher order method for approximating smooth solution parts. In this article, we study a new approach to FL methods. Relying on a classification of input data with respect to smoothness, we associate specific basis functions with the individual smoothness notions. Then, we construct a limiter as a linear combination of the members of parameter‐dependent families of basis functions, and we explore the possibility to optimize the parameters in interesting model situations to find a corresponding optimal limiter. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013
SP1 mediates the link between methylation of the tumour suppressor miR‐149 and outcome in colorectal cancer
Authors: Wang Feng , Ma Yan‐Lei , Zhang Peng , Shen Tong‐Yi , Shi Chen‐Zhang , Yang Yong‐Zhi , Moyer Mary‐Pat , Zhang Hui‐Zhen , Chen Hong‐Qi , Liang Yong , Qin Huan‐Long
Published: July 2012

Although recent studies indicate that DNA methylation contributes to the down‐regulation of microRNAs (miRNAs) in colorectal cancer (CRC), this field remains largely unexplored. To identify methylation‐silenced miRNAs and clarify their role in CRC, we performed a microarray analysis and screened for miRNAs that were induced in CRC cells by 5‐aza‐2′‐deoxycytidine treatment or by the knockdown of DNA methyltransferases. The DNA methylation status of the candidate miRNA was analysed by bisulphite sequencing PCR and methylation‐specific PCR. We found that miRNA‐149 (miR‐149) was epigenetically silenced in CRC and down‐regulation of miR‐149 was associated with hypermethylation of the neighbouring CpG island (CGI). Quantitative RT‐PCR analysis demonstrated that the miR‐149 level was markedly reduced in 51.6% of the CRC tissues compared with matched non‐cancerous tissues. In addition, low expression of miR‐149 was associated with a greater depth of invasion ($\it{p} = 0.012$), lower 5‐year survival rate ($\it{p} = 0.025$), and was found to be an independent prognostic factor for overall survival ($\it{p} = 0.016$) in a multivariate analysis. Moreover, transfection of miR‐149 inhibited cell growth and invasion of CRC cells in vitro. We also identified mRNA for Specificity Protein 1 (SP1, Sp1), a potential oncogenic protein, as a target of miR‐149. Our data suggest that, as a methylation‐sensitive miRNA, miR‐149 may play an important role as a tumour suppressor in CRC, which has prognostic and therapeutic implications. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Effect of silane coupling agent on the durability of epoxy adhesion for structural strengthening applications
Authors: Choi Sungwon , Maul Scott , Stewart Andrew , Hamilton H.R. , P. Douglas Elliot
Published: July 2012

In this article, the durability of the interfacial bonds between epoxy and concrete during hygrothermal exposure was investigated. Through the application of a silane coupling agent, we examined the hypothesis that hydrogen bonding plays a large role in the degradation of the interfacial bond between epoxy and concrete, in which displacement of epoxy with water induces the disruption of the interfacial hydrogen bond. This hypothesis suggests that durability can be enhanced with the use of a silane coupling agent by changing the interfacial hydrogen bonds to stronger covalent bonds. The slant shear test results show that the durability of the interfacial bond was significantly enhanced with the use of an epoxy‐functional silane coupling agent. Spectroscopic features using FTIR confirmed the changes in chemical nature of concrete after the silane modification. By calculating the percent contribution to the bond strength for each set of specimens, it was confirmed that the silane application improved the durability with exposure for all conditions; however, over time the improvement diminished. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Fluorescence quenching of fluoranthene by maleic anhydride in solution and during nonreactive and reactive twin‐screw extrusion
Authors: Methenni Amine , Mighri Frej , Elkoun Saïd , Fang Haixia , Cassagnau Philippe
Published: July 2012

Fluorescence quenching of fluoranthene by maleic anhydride (MAH) in polypropylene (PP) during twin‐screw extrusion (TSE) was investigated using an online fluorescence measurement system. The fluorescence quenching effect was clearly seen from the decrease of the peak intensity and integrated area of the residence time distribution (RTD) curves when MAH was introduced into PP. Fluorescence quenching effect in TSE was compared with that in chloroform solution and in both cases, it followed the linear Stern‐Volmer equation although it showed lower quenching effect in TSE than in solution. Using this quenching phenomenon, it was possible to measure online the grafting degree of PP with MAH in the TSE. The obtained results showed that MAH grafting degree and total conversion measured by both fluorescence technique and by Fourier transform infrared spectroscopy were in good agreement for MAH weight concentrations up to 0.8 wt%. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Effects of nanotube modification on the dielectric behaviors and mechanical properties of multiwall carbon nanotubes/epoxy composites
Authors: Guo Xiusheng , Yu Demei , Wu Jingshen , Min Chao , Guo Rongnan
Published: July 2012

Multiwall carbon nanotubes (MWNTs) were modified by three methods, namely, oxidizing the tubes and opening both ends, filling the tubes with Ag, and grafting the tubes with hexamethylene diamine. Modified MWNTs/epoxy composites were prepared by melt‐mixing epoxy resin with the tubes. Transmission electron microscope images showed that the modified MWNTs can be dispersed in the epoxy matrix homogeneously. The dielectric behaviors and mechanical properties of the composites were investigated. The dielectric and mechanical properties of the modified MWNTs/epoxy composites were considerably improved compared with those of the epoxy matrix. The tensile strengths of the Ag‐filled, opened, and grafted MWNTs composites at the same filler content of 1.1 wt% were higher by ∼30.5%, 35.6%, and 27.4%, respectively, than that of neat epoxy. The Izod notched impact strength of the grafted MWNTs/epoxy composite with filler content of 1.1 wt% was approximately four times higher than that of neat epoxy. A dielectric constant of ∼150 of the composite with 1.1 wt% Ag‐filled nanotubes was observed in the low‐frequency range, which was ∼40 times higher than that of the epoxy matrix. The proper modification of nanotubes provides a way to improve the properties of the polymer‐based composites. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Thermo‐sensitive electrospun fibers prepared by a sequential thiol‐ene click chemistry approach
Authors: Yang Hong , Zhang Qi , Lin Baoping , Fu Guodong , Zhang Xueqin , Guo Lingxiang
Published: July 2012

This manuscript describes a straightforward method to prepare stimuli‐responsive fibers by the combined technology of electrospinning and two facile thiol‐ene click chemistry processes: photo‐initialized thiol‐ene radical addition and thiol‐Michael nucleophilic addition. By controlling the molar ratio of poly((3‐mercaptopropyl)methylsiloxane) (PMMS) and the cross‐linker, triallyl cyanurate, PMMS‐based fibers can be partially photo‐crosslinked via UV illumination during electrospinning, to grant them the solvent‐resistant property, meanwhile leaving unreacted free mercapto groups on the surfaces, which could be further functionalized with stimuli‐responsive polymer brushes. To demonstrate the feasibility of this approach, a facile thiol‐Michael addition protocol between PMMS fibers with free thiol groups on the surfaces and maleimide‐terminated PNIPAM has been developed, which allows for the preparation of polysiloxane fibers with thermo‐responsive PNIPAM brushes on the surfaces. PMMS‐g‐PNIPAM fibers show thermo‐sensitive behavior to the environment, having a hydrophilic surface at 20°C (water contact angle ∼28°) and a hydrophobic surface at 45°C (water contact angle ∼132°). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012.
Copper‐mediated initiators for continuous activator regeneration atom transfer radical polymerization of acrylonitrile
Authors: Liu Xiao‐hui , Wang Jin , Zhang Fei‐jun , An Shu‐lin , Ren Yuan‐lin , Yu Yun‐hai , Chen Peng , Xie Shan
Published: July 2012

Initiators for continuous activator regeneration atom transfer radical polymerization technique was first accessed to acrylonitrile by using CuBr2/2,2′‐bipyridine as the catalyst, ethyl 2‐bromoisobutyrate as the halogen initiator, and azobis(isobutyronitrile) as the free radical initiator. The key to success is ascribed to the facile achievement of the rapid equilibrium between active species and dormant species. Effects of ligand, catalyst concentration, free radical initiator concentration, and reaction temperature on the polymerization reaction and molecular weight (MW) as well as polydispersity index (PDI) were investigated in detail. The polymerization proceeded in a controlled/living fashion even though the concentration of copper catalyst decreased to 50 ppm, which is evident in pseudo first‐order kinetics of polymerization, linear increase of molecular weight, low PDI, and high chain‐end functionality of the generated polymer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Elucidation of the mechanism of surface‐initiated atom transfer radical polymerization from a diazonium‐based initiator layer
Authors: Chernyy Sergey , Iruthayaraj Joseph , Ceccato Marcel , Hinge Mogens , Pedersen Steen Uttrup , Daasbjerg Kim
Published: July 2012

This study elucidates the influence of the atom transfer radical polymerization initiator structure, monolayer versus disordered multilayer, on the growth kinetics and the structural transition of poly(methyl methacrylate) (PMMA) brush layers. The multilayer initiator film, prepared by acylation of the electrografted 2‐phenylethanol layer using 2‐bromoisobutyryl bromide, consists of ∼4.6 times more tert‐butyl bromide groups compared to monolayer initiator prepared by self assembly technique. The results demonstrate the formation of precursor complex between CuI catalyst and the bromine initiator as a prerequisite step before the onset of polymerization. Furthermore, the PMMA brushes formed by the polymerization from the multilayered initiator layer at 50 °C are 20‐fold thicker compared to the polymerization at 25 °C due to the swelling of the multilayered initiator film. In contrast, the thickness of the PMMA layer on the monolayer initiator is less affected by the polymerization temperature. By varying the initiator density on the surface, the solvent content in the PMMA layer is shown to vary from 15% to 94%, resulting in the transition from concentrated over semidiluted to diluted brushes. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Morphosynthesis of poly[4‐(1,4‐phenylene)oxyphthalimide] and copolymers prepared by reaction‐induced crystallization during polymerization
Authors: Sawai Takashi , Wakabayashi Kanji , Yamazaki Shinichi , Uchida Tetsuya , Kimura Kunio
Published: July 2012

Morphosynthesis of poly[4‐(1,4‐phenylene)oxyphthalimide] (POPI) and poly[4‐(1,4‐phenylene)oxyphthalimide‐co‐4‐phthalimide] (POPI‐PPI) was examined by using the crystallization during the polymerization. The POPI fibrillar crystals were obtained as precipitates with the formation of spherical aggregates of plate‐like crystals. Some of the POPI fibrillar crystals were longer than 15 μm. They possessed high crystallinity and the molecules aligned perpendicular to the long direction of the fibers. On the other hand, one‐dimensional structures of POPI‐PPI such as ribbon, cone, rod, and fiber were obtained as precipitates by the copolymerization. The copolymer molecules might align along the long direction of the cone‐like crystals. The morphology of these poly(ether‐imide)s could be controlled by not only the polymerization condition but also with the aid of copolymerization. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Agriculture Grade Ammonium Nitrate as the Basic Ingredient of Massive Explosive Charges
Authors: Zygmunt Bogdan , Buczkowski Daniel
Published: July 2012

Prilled ammonium nitrate (AN) is manufactured globally in millions of tons and is mainly used as fertilizer or as the main ingredient of modern mining blasting explosives. The availability of AN poses a serious threat to public security as it enables preparation of massive explosive charges using a simple technology in order to carry out terrorist attacks. This paper examines the option of using agriculture AN manufactured in several Polish plants as the basic ingredient of explosive mixtures with liquid fuels or powdered aluminum. Fuel oil (FO), 2‐EHN and nitromethane were used as liquid fuels. Additionally, the effect of an inorganic additive (dolomite) in AN on the detonation velocity of mixtures of granulated and milled AN with various fuels was examined.
Effect of Porphyrin Doping on Thermodynamic Parameters of Pentaerythritol Tetranitrate (PETN) Single Crystals
Authors: Hikal Walid M. , Bhattacharia Sanjoy K. , Weeks Brandon L.
Published: July 2012

The search for ways to enhance the stability of PETN against sublimation and coarsening, as well as controlling its thermodynamic properties, is of great interest. In this article, the possibility to use biological molecules to enhance the stability of the important explosive PETN was investigated using thermogravemitric analysis (TGA). Doping PETN with free and metallated porphyrins result in the formation of more stable crystals. Hydrogen bonding between free porphyrins and metal coordination of metallated porphyrins is most likely to play an important role in the crystallization process of PETN. The results indicate the ability of porphyrins molecules to affect/control the thermodynamic properties of PETN inducing a desired higher stability against sublimation. This study opens the door to investigate the use of polymers to enhance the stability of energetic materials.
External validation of the updated briganti nomogram to predict lymph node invasion in prostate cancer patients undergoing extended lymph node dissection
Authors: Hansen Jens , Rink Michael , Bianchi Marco , Kluth Luis A. , Tian Zhe , Ahyai Sascha A. , Shariat Shahrokh F. , Briganti Alberto , Steuber Thomas , Fisch Margit , Graefen Markus , Karakiewicz Pierre I. , Chun Felix K.‐H.
Published: July 2012

PURPOSE

We aimed to test accuracy and generalizability of a recently updated nomogram to assess the probability of lymph node invasion (LNI), when applied to a different European cohort of men undergoing radical prostatectomy (RP) with extended pelvic lymph node dissection (ePLND).

MATERIALS AND METHODS

The study cohort consisted of 1,282 men with clinically localized PCa who underwent RP and ePLND, including removal of obturator, external iliac, and hypogastric lymph nodes, between 01/2007 and 08/2011. Descriptive measurements included preoperative clinical and biopsy variables, such as prostate‐specific antigen (PSA), clinical stage (CS), primary and secondary biopsy Gleason pattern, and percentage of positive cores. We used the area under curve (AUC) of the receiver operator characteristic analysis to quantify accuracy of the model to predict LNI. The extent of over‐ or under‐estimation was explored graphically within loess calibration plots.

RESULTS

The median number of removed lymph nodes was 15 with an interquartile range of 12–20. Twelve percent (n = 155) of men had LNI. Preoperative clinical and biopsy characteristics differed significantly (all P ≤ 0.002) between men with LNI and those without. External validation of the previously reported updated LNI nomogram showed very good accuracy (AUC: 0.829). A nomogram‐derived cut‐off of 4% could lead to a reduction of 48% of lymph node dissection, while missing 10% of patients with LNI.

CONCLUSIONS

We report the external validation of an updated LNI nomogram, demonstrating accuracy and applicability in a different European cohort. A nomogram‐derived cut‐off of 4% confirmed good performance characteristics within a different external validation cohort. Prostate 73: 211–218, 2013. © 2012 Wiley Periodicals, Inc.
Large electrostrictive effect in K0.99Li0.01Ta1−xNbxO3 lead‐free single crystals
Authors: Tian Hao , Jia Jieshu , Zhou Zhongxiang , Chen Deying
Published: July 2012

Paraelectric K0.99Li0.01Ta1−xNbxO3 (x = 0.38, 0.39, 0.40) lead‐free single crystals have been grown by the top‐seeded solution growth method. All the crystals have Curie temperature (Tc) close to room temperature (RT), and possess large relative dielectric constants near Tc. A scanning Michelson interferometer was used to investigate the electrostrictive (ES) behavior of the crystals. The crystals show pure ES characteristics and large electrosrictive coefficients. The ES coefficient Q11 of K0.99Li0.01Ta0.60Nb0.40O3 reaches as high as 0.12 m4/C2, about six times of the value of Pb(Mg1/3Nb2/3)O3 ceramics.
Atomic and electronic structure of rigid carbon atomic chains
Authors: Usanmaz D. , Srivastava G. P.
Published: July 2012

We have reported, from ab initio calculations, on the changes in the electronic and structural properties of short carbon atomic chains held rigidly between hydrogenated armchair graphene nanoribbons (AGNR) and zig‐zag graphene nanoribbons (ZGNR). Several lengths (N = 2–9 atoms) and forms of the chains have been considered. All models are found to be metallic in nature, with chemical bonding more like $\cdots {\rm C}- {\rm C}\equiv {\rm C}- {\rm C}\equiv {\rm C}\cdots $ (as in polyyne) for odd‐numbered chains and $\cdots {\rm C} = {\rm C} = {\rm C} = {\rm C}\cdots $ (as in cumulene) for even numbered chains. An examination of the variation of the density of states (DOS) near the Fermi level with chain length suggests the possibility for tunability of the metallic property of short carbon chains.
Hydrogen in C‐rich Si and the diffusion of vacancy–H complexes
Authors: Estreicher S. K. , Docaj A. , Bebek M. B. , Backlund D. J. , Stavola M.
Published: July 2012

The sites, gap levels, and migration barriers of interstitial H in Si are predicted. The hydrogenation of C‐rich Si results in the formation of H2*(C) and C2H2, in contrast to FZ‐Si where H2 molecules dominate. The fully saturated vacancy (VH4) also forms. This complex is normally stable up to 650 °C. However, in C‐rich Si, VH4 anneals around 550 °C while the VH3HC complex appears. There, C replaces one of the four Si nearest‐neighbors to the vacancy. This implies that VH4 begins to diffuse at 550 °C, and then traps at Cs. This in turn implies that all the VHn complexes (n = 1, 2, 3, 4) are mobile at moderate temperatures. In this paper, we discuss the energetics of H in Si, summarize the key experimental and theoretical results about H interactions in C‐rich Si, and discuss the migration paths and activation energies of the four VHn complexes.
Interfacial doping for efficient charge injection in organic semiconductors
Authors: Lee Jae‐Hyun , Kim Jang‐Joo
Published: July 2012

Interfacial doping in organic semiconductors (OSs) is an important technique to achieve efficient organic electronic devices. In this paper, we discuss how the charge injection into an OS can be enhanced by the insertion of a thin interfacial layer or an electrically doped OS layer between an electrode and an undoped OS. We present that the vacuum level shift and Fermi level modification by the electrical doping is the origin of the efficient charge injection through a metal–organic junction and an organic–organic junction. Application to organic electronics such as organic light‐emitting diodes (OLEDs) and organic photovoltaics (OPVs) is briefly summarized.
The Antioxidant and Anticancer Effects of Wild Carrot Oil Extract
Authors: Shebaby Wassim Nasri , El‐Sibai Mirvat , Smith Kikki Bodman‐ , Karam Marc Christoph , Mroueh Mohamad , Daher Costantine F.
Published: July 2012

Daucus carota L. ssp. carota (Apiacea) is used in traditional medicine in Lebanon and in different regions throughout the world. The present study investigates the in vitro anticancer activities of Daucus carota oil extract (DCOE) on four human cancer cell lines as well as its in vitro antioxidant activity. DCOE was extracted from the dried umbels with 50:50 acetone‐methanol. The oil extract was analyzed by gas chromatography–mass spectrometry and screened for its antioxidant properties in vitro using 1,1‐diphenyl‐2‐picryl hydrazyl free radical scavenging assay (DPPH), ferrous ion chelating assay (FIC) and the ferric reducing antioxidant power assay (FRAP). The anticancer activity of the oil extract against human colon (HT‐29, Caco‐2) and breast (MCF‐7, MDA‐MB‐231) cancer cell lines was evaluated using the trypan blue exclusion method and the WST‐1 cell proliferation assay. DCOE exhibited antioxidant activity in all assays used. The FRAP value was 164 ± 5.5 µmol FeSO4/g, and the IC50 values for DPPH and FIC assays were 2.1 ± 0.03 mg/ml and 0.43 ± 0.02 mg/ml, respectively. Also, DCOE demonstrated a significant increase in cell death and decrease in cell proliferation. The effect of DCOE on the cell lines exhibited time and dose‐dependent responses. The present study established that DCOE possesses both antioxidant and promising anticancer activities. Copyright © 2012 John Wiley & Sons, Ltd.
Avicenna's (Ibn Sina) the Canon of Medicine and Saffron (Crocus sativus): A Review
Authors: Hosseinzadeh Hossein , Nassiri‐Asl Marjan
Published: July 2012

In this review, we introduce the traditional uses of saffron and its pharmacological activities as described by either Avicenna in Book II, Canon of Medicine (al‐Qanun fi al‐tib) or from recent scientific studies. Modern pharmacological findings on saffron are compared with those mentioned in Avicenna's monograph. A computerized search of published articles was performed using MEDLINE, Scopus and Web of Science databases as well as local references. The search terms used were saffron, Crocus sativus, crocin, crocetin, safranal, picrocrocin, Avicenna and ‘Ibn Sina’. Avicenna described various uses of saffron, including its use as an antidepressant, hypnotic, anti‐inflammatory, hepatoprotective, bronchodilatory, aphrodisiac, inducer of labour, emmenagogue and others. Most of these effects have been studied in modern pharmacology and are well documented. The pharmacological data on saffron and its constituents, including crocin, crocetin and safranal, are similar to those found in Avicenna's monograph. This review indicates that the evaluation of plants based on ethnobotanical information and ancient books may be a valuable approach to finding new biological activities and compounds. Copyright © 2012 John Wiley & Sons, Ltd.
Intermolecular interactions—From some general features to conformational autocatalysis
Authors: Piela Lucjan
Published: July 2012

The intermolecular interaction is ubiquitous and influences the results of virtually every chemical or physical experiment. There are some important questions left in the theory of intermolecular interaction. One of such questions is: what kind of objects do interact. In the article, we recall a kind of unusual symmetry requirement in a physical theory related to this question. Also, we introduce a gradation of such choices of the interacting subsystems leading eventually to the concept of the most natural choice. Electrostatics plays a special role in the intermolecular interaction. We discuss why electrostatics remains important even if other interactions are strong. Next, the electrostatic interactions are shown to be important in the three‐dimensional (3D) structure of proteins occurring in Nature. Predicting the molecule's lowest‐energy conformation or configuration represents a formidable task. There were many attempts to solve this problem for protein molecules, for which it is believed their native conformation corresponds to the lowest free energy. The challenge to find this conformation from a given sequence of amino acids (AAs) is known as a “second genetic code.” In fact all of these attempts are based on some smoothing of the energy landscape. In the article, some of these smoothing techniques are described, which finally turned out to be highly successful in finding native structures of globular proteins. When discussing the contributions to the conformational energy the importance of the electrostatic interactions has been stressed. In particular, it turned out that the dipole moments of the NH and of the CO bonds in proteins functioning in nature are oriented to good accuracy along the local intramolecular electric field. Thanks to an enormous effort of the protein folding community it is possible to predict the native 3D structure of globular proteins. It is also possible to design such AA sequences, which fold to the desired protein 3D structure. A certain reliable theoretical technique of protein folding has been used to study a possibility of conformational autocatalysis. It turned out that such an effect has been predicted for a small protein of 32 AAs, with carefully designed AA sequence. This may be seen as a model of the prion disease propagation. © 2012 Wiley Periodicals, Inc.
A liquid chromatography/electrospray ionization tandem mass spectrometric method for quantification of asiatic acid from plasma: application to pharmacokinetic study in rats
Authors: Nair Sreenath Nandakumar , Menon Sasikumar , Shailajan Sunita
Published: July 2012

RATIONALE

Asiatic acid (AA), a pentacyclic triterpene from Centella asiatica (L.) Urban, has shown numerous therapeutic activities. However, none of the published works to date has used high‐performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) for determination of AA from biological fluids. Therefore, the present paper describes a sensitive HPLC/electrospray ionization (ESI)‐MS/MS method for quantification of AA in rat plasma.

METHODS

Ammonium adduct formation of AA was essential in the development of a sensitive method with the rat plasma samples being pre‐treated by a simple solid‐phase extraction method. The separation was achieved on a Cosmosil C18 column using a gradient mobile phase flow. Detection was performed using an Applied Biosystems API Q‐Trap 2000 mass spectrometer equipped with an ESI source operated in positive mode with colchicine used as internal standard.

RESULTS

An eight‐point calibration curve over the concentration range of 1.02–407.88 ng/mL for AA from rat plasma provided an optimum linear detector response (with r2 >0.9983). The mean percentage recovery (n = 3) for the low, middle and high quality control samples was 91.23 ± 1.88%, 90.36 ± 0.55% and 89.71 ± 0.21%, respectively. The intra‐day and inter‐day precision and accuracy of the quality control samples were within ≤5% and ±7% correspondingly.

CONCLUSIONS

The developed method was validated as per US FDA guidelines and applicability demonstrated by successful measurement of AA from plasma following oral administration of C. asiatica extracts to Wistar rats. The results suggest that the method could be applied to therapeutic monitoring of AA and pharmacokinetic studies in human volunteers. Copyright © 2012 John Wiley & Sons, Ltd.
Oxygen isotopic composition of fulgurites from the Egyptian Sahara and other locations
Authors: Longinelli Antonio , Serra Romano , Sighinolfi Giampaolo , Selmo Enricomaria , Sgavetti Maria
Published: July 2012

RATIONALE

Fulgurites are glassy crusts or hollow glassy tubes formed by the impact of a lightning strike on a target material on the Earth's surface. The oxygen isotopic composition of fulgurites has never been measured and, consequently, it is unknown whether or not isotopic fractionations take place between the target material and the fulgurite glass during the lightning event which is an excellent natural example of extremely fast melting process.

METHODS

Following well‐established procedures (high‐temperature reaction of the fulgurite material with BrF5, conversion into CO2 of the evolved O2 and measurement of the18O/16O ratio on a Finnigan Delta S mass spectrometer) we measured for the first time the oxygen isotopic composition of sets of fulgurites coming from various locations on the Earth's surface.

RESULTS

The range of isotopic values is quite large, probably reflecting the oxygen isotopic values of the target materials. In the case of fulgurites from the Sahara Desert the isotopic values obtained from the bulk material, quartz crystals sticking to the fulgurite body, tiny samples of loose sand coming from fulgurite bubbles, and sand samples collected near the fulgurites, are very close to one another.

CONCLUSIONS

Although we do not have indisputable evidence, we conclude that, at least in the case of oxygen, the fusion process of the material struck by lightning, as well as all the extremely fast high‐temperature fusion processes, probably take place without any isotopic fractionation effect. Copyright © 2012 John Wiley & Sons, Ltd.
Associations between variability of risk factors and health outcomes in longitudinal studies
Authors: Elliott Michael R. , Sammel Mary D. , Faul Jessica
Published: July 2012

Many statistical methods have been developed that treat within‐subject correlation that accompanies the clustering of subjects in longitudinal data settings as a nuisance parameter, with the focus of analytic interest being on mean outcome or profiles over time. However, there is evidence that in certain settings, underlying variability in subject measures may also be important in predicting future health outcomes of interest. Here, we develop a method for combining information from mean profiles and residual variance to assess associations with categorical outcomes in a joint modeling framework. We consider an application to relating word recall measures obtained over time to dementia onset from the Health and Retirement Survey. Copyright © 2012 John Wiley & Sons, Ltd.
Network meta‐analysis models to account for variability in treatment definitions: application to dose effects
Authors: Giovane Cinzia Del , Vacchi Laura , Mavridis Dimitris , Filippini Graziella , Salanti Georgia
Published: July 2012

For a network meta‐analysis, an interlinked network of nodes representing competing treatments is needed. It is often challenging to define the nodes as these typically refer to similar but rarely identical interventions.

The objectives of this paper are as follows: (i) to present a series of network meta‐analysis models that account for variation in the definition of the nodes and (ii) to exemplify the models where variation in the treatment definitions relates to the dose. Starting from the model that assumes each node has a ‘fixed’ definition, we gradually introduce terms to explain variability by assuming that each node has several subnodes that relate to different doses. The effects of subnodes are considered monotonic, linked with a ‘random walk’, random but exchangeable, or have a linear pattern around the treatment mean effect. Each model can be combined with different assumptions for the consistency of effects and might impact on the ranking of the treatments. Goodness of fit, heterogeneity and inconsistency were assessed. The models are illustrated in a star network for the effectiveness of fluoride toothpaste and in a full network comparing agents for multiple sclerosis.

The fit and parsimony measures indicate that in the fluoride network the impact of the dose subnodes is important whereas in the multiple sclerosis network the model without subnodes is the most appropriate. The proposed approach can be a useful exploratory tool to explain sources of heterogeneity and inconsistency when there is doubt whether similar interventions should be grouped under the same node. Copyright © 2012 John Wiley & Sons, Ltd.
Concise Review: A High-Content Screening Approach to Stem Cell Research and Drug Discovery
Authors: Xia Xiaofeng , Wong Stephen T.
Published: July 2012

High-throughput screening (HTS) is a technology widely used for early stages of drug discovery in pharmaceutical and biotechnology industries. Recent hardware and software improvements have enabled HTS to be used in combination with subcellular resolution microscopy, resulting in cell image-based HTS, called high-content screening (HCS). HCS allows the acquisition of deeper knowledge at a single-cell level such that more complex biological systems can be studied in a high-throughput manner. The technique is particularly well-suited for stem cell research and drug discovery, which almost inevitably require single-cell resolutions for the detection of rare phenotypes in heterogeneous cultures. With growing availability of facilities, instruments, and reagent libraries, small-to-moderate scale HCS can now be carried out in regular academic labs. We envision that the HCS technique will play an increasing role in both basic mechanism study and early-stage drug discovery on stem cells. Here, we review the development of HCS technique and its past application on stem cells and discuss possible future developments.
Mesenchymal Stem Cells Shape Microglia Effector Functions Through the Release of CX3CL1
Authors: Giunti Debora , Parodi Benedetta , Usai Cesare , Vergani Laura , Casazza Simona , Bruzzone Santina , Mancardi Gianluigi , Uccelli Antonio
Published: July 2012

Mesenchymal stem cells (MSC) display a remarkable ability to modulate the immune response and protect the central nervous system mainly through the release of soluble factors in a paracrine fashion, affecting the functional behavior of cells in the tissues. Here we investigated the effect of the interaction between MSC and microglia in vitro, and we dissected the molecular and cellular mechanisms of this crosstalk. We demonstrated that MSC impair microglia activation by inflammatory cues through the inhibition of the expression and release of inflammatory molecules and stress-associated proteins. We showed that MSC significantly increase microglial expression and release of molecules associated with a neuroprotective phenotype such as CX3CR1, nuclear receptor 4 family, CD200 receptor, and insulin growth factor 1. Interestingly, MSC can enhance functional changes on microglia as depicted by the increase of intracellular calcium concentration and phagocytic activity. This last event is associated with an increased expression of triggering receptor expressed on myeloid cells-2, an innate immune receptor involved in phagocytosis in the absence of inflammation. The observed effects on CX3CR1-expressing microglia are due to the release of CX3CL1 by MSC, driven by inflammatory signals, as demonstrated by the reversal of the observed results when CX3CL1 expression was silenced in MSC or its release was blocked. Finally, we showed that exogenous CX3CL1 induce phenotypic and functional changes of microglia similar to those induced by MSC. These findings demonstrate that MSC instruct, through the release of CX3CL1, microglia responsiveness to proinflammatory signals by modulating constitutive “calming” receptors, typically expressed by “steady-state microglia” thus switching microglia from a detrimental phenotype to a neuroprotective one.