bluuebunny/crossref_metadata_2025_split huggingface dataset:
Teaching the fluctuation test in silico by using mutate: A program to distinguish between the adaptive and spontaneous mutation hypotheses
Authors: Carvajal‐Rodríguez Antonio 
Published: June 2012

AbstractMutate is a program developed for teaching purposes to impart a virtual laboratory class for undergraduate students of Genetics in Biology. The program emulates the so‐called fluctuation test whose aim is to distinguish between spontaneous and adaptive mutation hypotheses in bacteria. The plan is to train students in certain key multidisciplinary aspects of current genetics such as sequence databases, DNA mutations, and hypothesis testing, while introducing the fluctuation test. This seminal experiment was originally performed studying Escherichia coli resistance to the infection by bacteriophage T1. The fluctuation test initiated the modern bacterial genetics that 25 years later ushered in the era of the recombinant DNA. Nowadays we know that some deletions in fhuA, the gene responsible for E. coli membrane receptor of T1, could cause the E. coli resistance to this phage. For the sake of simplicity, we will introduce the assumption that a single mutation generates the resistance to T1. During the practical, the students use the program to download some fhuA gene sequences, manually introduce some stop codon mutations, and design a fluctuation test to obtain data for distinguishing between preadaptative (spontaneous) and induced (adaptive) mutation hypotheses. The program can be launched from a browser or, if preferred, its executable file can be downloaded from http://webs.uvigo.es/acraaj/MutateWeb/Mutate.html. It requires the Java 5.0 (or higher) Runtime Environment (freely available at http://www.java.com).
Blended learning in biochemistry education: Analysis of medical students' perceptions
Authors: de Fátima Wardenski Rosilaine , de Espíndola Marina Bazzo , Struchiner Miriam , Giannella Taís Rabetti 
Published: June 2012

AbstractThe objective of this study was to analyze first‐year UFRJ medical students' perceptions about the implementation of a blended learning (BL) experience in their Biochemistry I course. During the first semester of 2009, three Biochemistry professors used the Constructore course management system to develop virtual learning environments (VLEs) for complementing course Modules I, II, and IV, using different resources and activities. Forty‐nine students (46%) took part in the study. Results show that, in general, students gave positive evaluations to their experiences with BL, indicating that the VLEs have not only motivated but also facilitated learning. Most of the students reported that access to resources in the three modules provided a more in‐depth approach to Biochemistry education and greater study autonomy. Students suggested that the VLEs could be better used for promoting greater communication among participants.
Development of the enzyme–substrate interactions concept inventory
Authors: Bretz Stacey Lowery , Linenberger Kimberly J. 
Published: June 2012

AbstractEnzyme function is central to student understanding of multiple topics within the biochemistry curriculum. In particular, students must understand how enzymes and substrates interact with one another. This manuscript describes the development of a 15‐item Enzyme–Substrate Interactions Concept Inventory (ESICI) that measures student understanding of enzyme–substrate interactions. The validity and reliability of ESICI data were established through multiple methods. Results from the administration of the ESICI to biochemistry students across the United States (N = 707) are discussed in terms of instrument quality. The manuscript concludes with suggestions for how to use the ESICI for both teaching and biochemistry education research.
Cembranoid, Steroid, and Sesquiterpenoid Derivatives from the South China Sea Soft Coral Sinularia numerosa
Authors: Qin Mingli , Li Xiaoming , Wang Bingui 
Published: June 2012

AbstractTwo new cembranoids, namely, sinumerolides A and B (1 and 2), one new steroid, 7β‐hydroxygorgosterol (7), along with four known cembranoid derivatives (3–6), four known steroids (8–11), and four known africane sesquiterpenoids (12–15), were isolated and identified from the marine soft coral Sinularia numerosa that was collected from South China Sea waters. The structures of these metabolites were elucidated on the basis of extensive spectroscopic analysis and by comparison of their spectral data with those of literature reports. The isolated compounds were evaluated for the antimicrobial and cytotoxic activity.
Design, Synthesis and Biological Evaluation of 2‐(2‐Aryl‐morpholino‐4‐yl)ethyl Esters of Indomethacin as Potential Cyclooxygenase‐2 (COX‐2) Inhibitors
Authors: Shi Lei , Hu Aixi , Xu Jiangping , Jiang Yiping 
Published: June 2012

AbstractA number of novel 2‐(2‐arylmorpholino‐4‐yl)ethyl 1‐(4‐chlorobenzoyl)‐5‐methoxy‐2‐methyl‐1H‐indol‐3‐acetate hydrochlorides were synthesized and tested for their cyclooxygenase (COX‐1 and COX‐2) inhibition properties in vitro. Many of these compounds exhibited moderate to good selective COX‐2 inhibition, and subtle structural changes in the substituents on the side chain of the ester moiety altered the inhibitory properties significantly. 2‐[2‐(4‐Butoxyphenyl)morpholino‐4‐yl]ethyl 1‐(4‐chlorobenzoyl)‐5‐methoxy‐2‐methyl‐1H‐indol‐3‐acetate hydrochloride (1f), showed good selective COX‐2 inhibitory activity (Selective index (SI) 182), which is comparative with celecoxib (SI 214), a COX‐2 inhibitor of diarylpyrazoles. While 2‐[2‐(2,4‐dichloro‐5‐fluorophenyl)morpholino‐4‐yl]ethyl 1‐(4‐chlorobenzoyl)‐5‐methoxy‐2‐methyl‐1H‐indol‐3‐acetate hydrochloride (1g), showed greater selective COX‐2 inhibitory activity (SI 358) than celecoxib. Both compounds were identified as compromising derivatives in this class to reduce the side effects generated by nonsteroidal anti‐inflammatory drugs (NSAIDs) indomethacin.
Homology in the development of triadic interaction and language
Authors: Moore Chris 
Published: June 2012

AbstractConceiving of development with reference to homology can help identify developmental continuity where surface form shows considerable variation across age. I argue that there is a homology of structure between the object‐centred, or triadic, interactions that emerge in infancy and later language. The structure of triadic interaction in infancy is first described as involving joint attention and joint engagement about a shared topic, and then a case is made that this structure is maintained through three levels of complexity in language—single word utterances, multiword utterances, and finally complex constructions. A focus on the homological relation between these social interactive structures may be useful in revealing developmental continuities where these may be obscured by quite different surface forms. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 55: 59–66, 2013.
The concept of homology in the development of handedness
Authors: Michel George F. 
Published: June 2012

AbstractThe construct of homology in the development of behavior is examined using human handedness. Research on the development of hand‐use preferences in infants provides some evidence that it may be homologous with adult handedness. Nevertheless, I propose that the construct of homology may not be relevant to the study of human behavioral development. However, other constructs from developmental biology may prove useful in improving developmental psychological research. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 55: 84–91, 2013.
Fatty acid profile, oxidative stability, and sensory properties of breast meat from turkeys fed diets with a different n‐6/n‐3 PUFA ratio
Authors: Jankowski Jan , Zdunczyk Zenon , Mikulski Dariusz , Juskiewicz Jerzy , Naczmanski Jakub , Pomianowski Janusz F. , Zdunczyk Przemysław 
Published: June 2012

AbstractThe objective of this study was to determine the effect of diets with a different n‐6/n‐3 PUFAs ratio (7.31, 4.43, and 0.99), resulting from the addition of different dietary oils: soybean, rapeseed, and linseed (diets S, R, and L, respectively), on the fatty acid (FA) profile, oxidative status, and sensory properties of turkey breast meat. After 15 wk of feeding, breast meat yield and chemical properties of the meat were similar in all groups. Raw breast meat of R turkeys had a significantly higher content of all‐trans‐retinol and α‐tocopherol, compared with S and L. The physicochemical properties of breast meat, including pH, color, drip loss, and cooking loss, did not differ significantly. Cooked meat samples differed significantly with respect to the concentrations of oleic acid, linoleic acid (S and R>L), and linolenic acid (S and R<L). Compared with S and R, breast meat of L turkeys was characterized by higher concentrations of total PUFAs (35.1 vs. 30.1 and 29.3%), a significantly lower n‐6/n‐3 PUFAs ratio (1.51 vs. 5.43 and 5.07%) and a higher thiobarbituric acid reactive substances content (TBARS; 31.9 vs. 26.4 and 26.7 nmol/g). After 4 months of deep‐freeze storage the n‐6/n‐3 PUFAs ratio did not deteriorate. It may be concluded that replacing soybean oil with linseed oil, but not with rapeseed oil, increased the proportion of PUFAs in the total FAs pool and improved the n‐6/n‐3 PUFAs ratio, yet it also adversely affected the sensory properties and oxidative stability of meat. Both raw and stored breast meat from L turkeys was susceptible to oxidative changes, as manifested by the significantly higher TBARS concentrations (17.07 and 81.06) compared with those of the S group (10.91 and 53.00 nmol/g, respectively).Practical applications: Studies investigating the possibility of increasing the health benefits of poultry meat have been performed mostly on broilers, while the problem remains poorly researched in turkeys. Our findings show that linseed oil, in contrast to rapeseed oil, is a good source of PUFAs, in particular n‐3 PUFAs, that can be effectively transferred from feed to carcass lipids. However, desirable changes in the fatty acid profile are accompanied by increased susceptibility to lipid oxidation and deterioration of the sensory properties of meat. Thus, the linseed oil content of turkey diets should be reduced, or diets supplemented with linseed oil should be fed for shorter periods of time to alleviate the negative effects of linseed oil on the sensory attributes and oxidative status of meat.
Free sterols and steryl glycosides in sunflower seeds with high phytosterol contents
Authors: Aguirre Marta R. , Ruiz‐Méndez M. Victoria , Velasco Leonardo , Dobarganes M. Carmen 
Published: June 2012

AbstractIn this paper, the distribution of sterol compounds has been analyzed in 10 samples of new sunflower seeds with high contents of phytosterols. The sunflower seeds were first extracted with hexane and the residual oil was then extracted with a mixture of chloroform:methanol (2:1). In addition, the lipids from the defatted seeds and from the total seeds were analyzed after acid hydrolysis and subsequent extraction. The evaluation of the sterol compounds was performed by high temperature GC directly in the sylanized unsaponifiable matter using α‐cholestanol as internal standard. This procedure allows for the quantification of free sterols and steryl glycosides in the oils extracted by hexane and chloroform:methanol (2:1) while in defatted meal and total seeds, they are determined as free sterols. The main characteristics of the fractions extracted by hexane were a variable oil content (19.8–38.7%) with medium unsaponifiable matter (1.4–4.8%), The major sterol compounds in the oil extracted by hexane were free sterols (4034–8507 mg/kg) while steryl glycosides were in low concentrations (80–280 mg/kg). On the contrary, the fraction extracted by chloroform:methanol had low lipid content (2.2–6.7%) with a high unsaponifiable matter (12.6–28.2%). The major sterol compounds in this fraction were steryl glycosides (9711–22 514 mg/kg). Finally, a third of the total sterols remained in the meal after the extraction of edible oil by hexane.
Prediction of fatty acid composition of vegetable oils based on rheological measurements using nonlinear models
Authors: Yalcin Hasan , Toker Omer Said , Ozturk Ismet , Dogan Mahmut , Kisi Ozgur 
Published: June 2012

AbstractThe aim of this study was to model the fatty acid composition of vegetable oils by using the adaptive neuro fuzzy inference system (ANFIS) and artificial neural network (ANN) based on rheological measurements. For this aim, seven different refined vegetable oils (hazelnut, soybean, sunflower, olive, canola, corn, and cotton seed) were used. Olive oil had the highest viscosity value of 0.067 Pa s. Principal component analysis (PCA) was performed to determine the correlations among the fatty acids of the oils to reduce parameters which were modeled. PC1 composed of C18:0, C18:1, C18:2, and C20:0 as PC2 composed of C16:0, C18:3, and C22:0. After determination of the fatty acid composition and the rheological properties of the oils, ANN and ANFIS models were established. The inputs were selected as oil type, shear rate and shear stress and the outputs were C16:0 and C18:2. The root mean square error (RMSE), mean absolute error (MAE), and determination coefficient (R2) were used for testing the accuracy of the models. This comparison showed that ANFIS and ANN achieved a satisfactory prediction for fatty acid composition of the vegetable oils studied and ANFIS is better than ANN.Practical applications: Determination of the fatty acid composition of vegetable oils is important for the assessment of the purity of the oils as well as the nutritional quality. The fatty acid composition of the oils affects their rheological characteristics. Rheological measurements are easier than chromatographic analysis. Therefore, we aimed to establish a model for prediction of the fatty acid composition of the oils based on their rheological behaviors.
Assessing a Spectroelectrochemical Sensor’s Performance for Detecting [Ru(bpy)3]2+ in Natural and Treated Water
Authors: Abu Eme A. , Bryan Samuel A. , Seliskar Carl J. , Heineman William R. 
Published: June 2012

AbstractA spectroelectrochemical sensor that combines three modes of selectivity in a single device was evaluated in natural and treated water samples using tris‐(2,2′‐bipyridyl) ruthenium(II) dichloride hexahydrate, [Ru(bpy)3]2+, as a model analyte. The sensor was an optically transparent indium tin oxide (ITO) electrode coated with a thin film of partially sulfonated polystyrene‐block‐poly(ethylene‐ran‐butylene)‐block‐polystyrene (SSEBS). As the potential of the ITO electrode was cycled from +0.7 to +1.3 V, the analyte changed from the colored [Ru(bpy)3]2+ complex to colorless [Ru(bpy)3]3+ complex and the change in absorbance at 450 nm was used as the optical signal for quantification. Calibration curves were obtained for [Ru(bpy)3]2+ in natural well water, river water and treated tap water with detection limits of 108, 139 and 264 nM, respectively. A standard addition method was developed to determine an ‘unknown’ spike addition concentration of [Ru(bpy)3]2+ in well water. The spectroelectrochemical sensor determined the concentration of [Ru(bpy)3]2+ spiked into a sample of Hanford well water to be 0.39±0.03 µM versus the actual concentration of 0.40 µM.
Learned integration of visual, vestibular, and motor cues in multiple brain regions computes head direction during visually guided navigation
Authors: Fortenberry Bret , Gorchetchnikov Anatoli , Grossberg Stephen 
Published: June 2012

AbstractEffective navigation depends upon reliable estimates of head direction (HD). Visual, vestibular, and outflow motor signals combine for this purpose in a brain system that includes dorsal tegmental nucleus, lateral mammillary nuclei, anterior dorsal thalamic nucleus, and the postsubiculum. Learning is needed to combine such different cues to provide reliable estimates of HD. A neural model is developed to explain how these three types of signals combine adaptively within the above brain regions to generate a consistent and reliable HD estimate, in both light and darkness, which explains the following experimental facts. Each HD cell is tuned to a preferred head direction. The cell's firing rate is maximal at the preferred direction and decreases as the head turns from the preferred direction. The HD estimate is controlled by the vestibular system when visual cues are not available. A well‐established visual cue anchors the cell's preferred direction when the cue is in the animal's field of view. Distal visual cues are more effective than proximal cues for anchoring the preferred direction. The introduction of novel cues in either a novel or familiar environment can gain control over a cell's preferred direction within minutes. Turning out the lights or removing all familiar cues does not change the cell's firing activity, but it may accumulate a drift in the cell's preferred direction. The anticipated time interval (ATI) of the HD estimate is greater in early processing stages of the HD system than at later stages. The model contributes to an emerging unified neural model of how multiple processing stages in spatial navigation, including postsubiculum head direction cells, entorhinal grid cells, and hippocampal place cells, are calibrated through learning in response to multiple types of signals as an animal navigates in the world. © 2012 Wiley Periodicals, Inc.
Stable isotopes as indicators for seasonally dominant nitrogen cycling processes in a subarctic lake
Authors: Gu Binhe 
Published: June 2012

AbstractNitrogen stable isotopes (δ15N) of dissolved inorganic nitrogen (DIN = NH4+ and NO3–), dissolved organic nitrogen (DON), and particulate organic nitrogen (PON) were measured in Smith Lake, Alaska to assess their usefulness as proxies for the biological nitrogen cycling processes, nutrient concentration, and lake productivity. Large seasonal variations in δ15NH4+, δ15NO3– and δ15NPON occurred in response to different processes of nitrogen transformation that dominated a specific time period of the annual production cycle. In spring, 15N depletion in all three pools was closely related to the occurrences of a N2‐fixing cyanobacterial bloom (Anabaena flos‐aquae). In summer, δ15NPON increased as phytoplankton community shifted to use NH4+ and decreased as a brief N2‐fixing bloom (Aphanizomenon flos‐aquae) occurred in August. In early and mid‐winter, microbial nitrogen processes were dominated by nitrification that resulted in the largest isotope fractionation between NO3– and NH4+ in the annual cycle. This was followed by denitrification that led to the highest 15N enrichment in NO3–. A peak of NH4+ assimilation by phytoplankton along with the elevated δ15NPON and Chl a concentration occurred just before the ice break due to increased light penetration. The δ15NDON displayed little temporal and spatial variations. This suggests that the DON pool was not altered by biological transformations of nitrogen as the results of its large size and possibly refractory nature. There was a positive correlation between Chl a concentration and δ15NPON, and a negative correlation between NH4+ and δ15NPON, suggesting that δ15NPON is a useful proxy for nitrogen productivity and ammonium concentration. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spatial Distribution of Macroinvertebrate Community along a Longitudinal Gradient in a Eutrophic Reservoir‐Bay during Different Impoundment Stages, China
Authors: Zhang Min , Cai Qinghua , Xu Yaoyang , Kong Linghui , Tan Lu , Wang Lan 
Published: June 2012

AbstractThe longitudinal patterns of the macroinvertebrate community in the Xiangxi Bay of the Three Gorges Reservoir (TGR) were investigated during the second (2nd) and third (3rd) impoundment stages (October 2006–July 2010), to test the effects of increased water level fluctuations (WLF) on the macroinvertebrates. By comparing to the former reports of the first (1st) impoundment stage (inter‐annual WLF 4 m), we found that oligochaetes dominated in three different stages in the Xiangxi Bay. However, the total abundance of macroinvertebrates showed a dramatical decline from the 1st to 2nd stage (inter‐annual WLF 11 m), but changed slightly from the 2nd to 3rd stage (inter‐annual WLF 30 m). This indicated that higher WLF in the 2nd stage had already greatly reduced the macroinvertebrates abundance, thereby the disturbance in the 3rd stage could only slightly affect the already reduced abundance. Three longitudinal zones (the mainstream zone, the lacustrine zone and the transitional zone) were found based on the macroinvertebrate density, biomass, and taxa richness, combined with the geographical location of each site. Significant differences in density and biomass of macroinvertebrate were found among different zones (P < 0.05), yet no significant difference was found in taxa richness (P > 0.05). Two‐way indicator species analysis showed that the community type in most sites varied in different seasons from the 2nd stage, exhibiting a dynamic zonation pattern, which differed with the stable pattern of the 1st stage. This seasonal feature was coupled to the seasonal changes of the WLF. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
‘Go with the flow ’: A review of methods and advancements in blood flow imaging
Authors: Daly Susan M. , Leahy Martin J. 
Published: June 2012

AbstractPhysics has delivered extraordinary developments in almost every facet of modern life. From the humble thermometer and stethoscope to X‐Ray, CT, MRI, ultrasound, PET and radiotherapy, our health has been transformed by these advances yielding both morphological and functional metrics. Recently high resolution label‐free imaging of the microcirculation at clinically relevant depths has become available in the research domain. In this paper, we present a comprehensive review on current imaging techniques, state‐of‐the‐art advancements and applications, and general perspectives on the prospects for these modalities in the clinical realm. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quiescence and attenuated DNA damage response promote survival of esophageal cancer stem cells
Authors: Chen Yulin , Li Dan , Wang Dapeng , Liu Xuefeng , Yin Ning , Song Yongmei , Lu Shih Hsin , Ju Zhenyu , Zhan Qimin 
Published: June 2012

AbstractAccumulating evidence indicates cancer stem cells (CSCs) possess the capability to resist DNA‐damage induced cell death, whereas the mechanism is largely unknown. Here we show that cell cycle status and DNA damage response (DDR) in CSCs probably contribute to their survival in genotoxic insults. In this study, we isolated esophageal cancer stem cells (ECSCs) from esophageal cancer cell line EC9706 by side‐population (SP) phenotype through flow cytometry and found that ECSCs preferentially stay quiescent as compared to the non‐ECSCs and are more resistant to DNA damage agents. Further study revealed that ECSCs express a lower level of EGFR, phosphoralated Stat3, and c‐Myc, yet abnormally upregulated p27. More interestingly, different from non‐ECSCs, when suffering DNA damage agents, ECSCs showed attenuated DDR, as well as declined DNA repair potential. These data indicated ECSCs probably employed an impaired DDR to handle severe genomic insults. Conclusively, we infer that the damage‐resistance ability of ECSCs is likely attributed to their slow‐cycling status and avoidance of apoptosis or senescence triggered by an excessive DDR. J. Cell. Biochem. 113: 3643–3652, 2012. © 2012 Wiley Periodicals, Inc.