bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical and experimental investigations on migration behavior of weak monoprotic acids in continuous two‐dimensional ion exchange/reversed phase CEC
Authors: Zhu Yaxian , Zhang Lingyi , Qian Junhong , Gao Fangyuan , Ma Fei , Zhang Weibing
Published: August 2012

A continuous 2D ion exchange/RP CEC system was constructed in this report and retention characteristics of weak monoprotic acids in the column were investigated theoretically. The transport equations were deduced for predicting migration behavior of weak monoportic acids based on mixing model combining ion exchange, RP, and electrophoretic separation mechanism. The influences of separation voltage, length of capillary, pH value, and ionic strength of buffer and concentration of organic modifier in mobile phase on the separation were well described by the equations. It was verified that the migration rate of solute was linearly related to voltage in the case of lower voltage, decreased with the increase of the first‐dimensional length, and . The retention time of solute increased with enhancing ionic strength and concentration of organic modifier. These theoretical results were all demonstrated by the relevant experiments. The relevant application was performed for the aqueous extract of Rhizoma gastrodiae, showing the obvious potential in method development for the analysis of complex samples.
Capillary electrophoresis‐laser‐induced fluorescence detection of rat brain catecholamines with microwave‐assisted derivatization
Authors: Liu Wan‐Ling , Hsu Yi‐Fen , Liu Yu‐Wei , Singco Brenda , Chen Ssu‐Wei , Huang Hsi‐Ya , Chin Ting‐Yu
Published: August 2012

In this study, a rapid and sensitive method is described for the catecholamines detection in rat brain. CE with LIF detection for the determination of FITC derivatized catecholamines (dopamine, epinephrine, and norepinephrine) was demonstrated. Conventional water bath and microwave‐assisted derivatization methods were employed and a significant reduction in the derivatization time from 2 h for the conventional water bath at room temperature (ca. 25°C) to 2 min for the microwave‐assisted derivatization was achieved. Online sample concentration of field‐amplified sample stacking (FASS) method was employed to achieve higher sensitivities (the detection limits obtained in the normal injection mode ranged from 2.6 to 4.5 ng L−1 and in the FASS mode ranged from 22 to 34 pg L−1). Furthermore, this microwave‐assisted derivatization CE–LIF method successfully determined catecholamines in rat brain with as low as 100 ng L−1 (FASS mode) to 10 μg L−1 (normal injection mode). This CE–LIF method provided better detection ability when compared to the best reports on catecholamines analyses.
Robust spectral estimation for speed of sound with phase shift correction applied online in yeast fermentation processes
Authors: Hussein Walid B. , Hussein Mohamed A. , Becker Thomas
Published: August 2012

Ultrasound techniques are well suited to provide real‐time characterization of bioprocesses in non‐invasive, non‐contact, and non‐destructive low‐power consumption measurements. In this paper, a spectral analysis method was proposed to estimate time of flight (TOF) between the propagated echoes, and its corresponding speed of sound (USV). Instantaneous power spectrum distribution was used for accurate detection of echo start times, and phase shift distribution for correcting the involved phase shifts. The method was validated by reference USV for pure water at 9–30.8°C, presenting a maximum error of 0.22%, which is less than that produced by the crosscorrelation method. Sensitivity analyses indicated a precision of 6.4 × 10−3% over 50 repeated experiments, and 0.11% over two different configurations. The method was competently implemented online in a yeast fermentation process, and the calculated USV was combined with temperature and nine signal features in an artificial neural network. The network was designed by back propagation algorithm to estimate the instantaneous density of the fermentation mixture, producing a maximum error of 0.95%.
A statin‐regulated microRNA represses human c‐Myc expression and function
Authors: Takwi Apana A. L. , Li Yan , Becker Buscaglia Lindsey E. , Zhang Jingwen , Choudhury Saibyasachi , Park Ae Kyung , Liu Mofang , Young Ken H. , Park Woong‐Yang , Martin Robert C. G. , Li Yong
Published: August 2012

c‐Myc dysregulation is one of the most common abnormalities found in human cancer. MicroRNAs (miRNAs) are functionally intertwined with the c‐Myc network as multiple miRNAs are regulated by c‐Myc, while others directly suppress c‐Myc expression. In this work, we identified miR‐33b as a primate‐specific negative regulator of c‐Myc. The human miR‐33b gene is located at 17p11.2, a genomic locus frequently lost in medulloblastomas, of which a subset displays c‐Myc overproduction. Through a small‐scale screening with drugs approved by the US Food and Drug Administration (FDA), we found that lovastatin upregulated miR‐33b expression, reduced cell proliferation and impaired c‐Myc expression and function in miR‐33b‐positive medulloblastoma cells. In addition, a low dose of lovastatin treatment at a level comparable to approved human oral use reduced tumour growth in mice orthotopically xenografted with cells carrying miR‐33b, but not with cells lacking miR‐33b. This work presents a highly promising therapeutic option, using drug repurposing and a miRNA as a biomarker, against cancers that overexpress c‐Myc.
Unveiling Case‐Control Relationships in Designing a Simple and Powerful Method for Detecting Gene‐Gene Interactions
Authors: Canela‐Xandri Oriol , Julià Antonio , Gelpí Josep Lluís , Marsal Sara
Published: August 2012

The detection of gene‐gene interactions (i.e., epistasis) in the human genome is becoming decisive for the complete characterization of the genetic factors associated with complex binary traits. Despite the fact that many methods have been developed to address this challenging issue, their performance still remains insufficient. We will show how case and control groups store complementary information regarding interactions, and the use of this fundamental property in the design of a new, rapid, and highly powerful epistasis analysis method. Unlike previous approaches where statistical methods are tested over a very limited range of situations, we have performed an exhaustive evaluation of the power of our new method. To this end, we also propose a more comprehensive interpretation of epistasis in which genotype interactions may be of risk, protective, or neutral. In this extended view of genetic interactions, we demonstrate that our method has superior performance than existing approaches, thus, providing a highly powerful tool for the identification of gene‐gene interactions associated with binary traits.
The presence of behavioural and psychological symptoms and progression to dementia in the cognitively impaired older population
Authors: van der Linde Rianne M. , Stephan Blossom C. M. , Matthews Fiona E. , Brayne Carol , Savva George M. ,   on behalf of the Medical Research Council Cognitive Function and Ageing Study
Published: August 2012

Objective

Behavioural and psychological symptoms (BPS) are common in the older population and may be an indication of early dementia. We explored the predictive effect of the presence of BPS on the 2‐year progression to dementia in a cognitively impaired population aged 65 years and over without dementia at baseline.

Methods

Twelve symptoms were measured in 2024 participants without dementia at baseline as part of a population‐based longitudinal study of ageing. The risk of progression to dementia was predicted in those with cognitive impairment for each individual BPS and using a BPS composite score.

Results

Wandering and persecution were independently associated with progression to dementia after adjustment for socio‐demographic factors, cognitive domains and other BPS. When stratifying by cognitive function, those with low cognition (MMSE 0–18) and 4 or more BPS were more likely to progress to dementia than those without BPS.

Conclusions

We have shown that some psychiatric symptoms are associated with increased short‐term progression to dementia in those with low cognition. The predictive effect of BPS in dementia progression has implications for risk stratification of those at high risk of progression to dementia, along with memory impairment, other cognitive impairment and health variables. Copyright © 2012 John Wiley & Sons, Ltd.
Hepatic encephalopathy is associated with decreased cerebral oxygen metabolism and blood flow, not increased ammonia uptake
Authors: Dam Gitte , Keiding Susanne , Munk Ole L. , Ott Peter , Vilstrup Hendrik , Bak Lasse K. , Waagepetersen Helle S. , Schousboe Arne , Sφrensen Michael
Published: August 2012

Studies have shown decreased cerebral oxygen metabolism (CMRO2) and blood flow (CBF) in patients with cirrhosis with hepatic encephalopathy (HE). It remains unclear, however, whether these disturbances are associated with HE or with cirrhosis itself and how they may relate to arterial blood ammonia concentration and cerebral metabolic rate of blood ammonia (CMRA). We addressed these questions in a paired study design by investigating patients with cirrhosis during and after recovery from an acute episode of HE type C. CMRO2, CBF, and CMRA were measured by dynamic positron emission tomography (PET)/computed tomography (CT). Ten patients with cirrhosis were studied during an acute episode of HE; nine were reexamined after recovery. Nine patients with cirrhosis with no history of HE served as controls. Mean CMRO2 increased from 0.73 μmol oxygen/mL brain tissue/min during HE to 0.91 μmol oxygen/mL brain tissue/min after recovery (paired t test; P < 0.05). Mean CBF increased from 0.28 mL blood/mL brain tissue/min during HE to 0.38 mL blood/mL brain tissue/min after recovery (P < 0.05). After recovery from HE, CMRO2 and CBF were not significantly different from values in the control patients. Arterial blood ammonia concentration decreased 20% after recovery (P < 0.05) and CMRA was unchanged (P > 0.30); both values were higher than in the control patients (both P < 0.05). Conclusion: The low values of CMRO2 and CBF observed during HE increased after recovery from HE and were thus associated with HE rather than the liver disease as such. The changes in CMRO2 and CBF could not be linked to blood ammonia concentration or CMRA. (Hepatology 2013)
Identification and validation of new autoantibodies for the diagnosis of DCIS and node negative early‐stage breast cancers
Authors: Lacombe Jérôme , Mangé Alain , Jarlier Marta , Bascoul‐Mollevi Caroline , Rouanet Philippe , Lamy Pierre‐Jean , Maudelonde Thierry , Solassol Jérôme
Published: August 2012

Evidence of circulating autoantibodies in cancer patient sera has created opportunities for exploiting them as biomarkers. We report the identification and the clinical validation of an autoantibody panel in newly diagnosed patients with early‐stage breast cancer. Proteomic approach and serological screening of a discovery set of sera (n = 80) were performed to identify tumor‐associated antigens (TAAs). Autoantibody levels were then measured in an independent validation set (n = 182) against a panel of five TAAs by enzyme‐linked immunosorbent assay. Sixty‐seven antigens that elicited a specific humoral response in breast cancer were identified and five antigens (GAL3, PAK2, PHB2, RACK1 and RUVBL1) were selected for validation. GAL3 and RACK1 showed significantly increased reactivity in early‐stage breast cancer. When combined, the five markers significantly discriminated early‐stage cancer from healthy individuals (AUC = 0.81; 95% CI [0.74–0.86]). Interestingly, this value was high in both node‐negative early‐stage primary breast cancer (AUC = 0.81; 95% CI [0.72–0.88]) and ductal carcinoma in situ (AUC = 0.85; 95% CI [0.76–0.95]) populations. This autoantibody panel could be useful as a diagnostic tool in a screening strategy of early‐stage invasive breast cancer and preinvasive breast cancer. It could be particularly appropriate in complement to mammography for women with high breast density.
Resolution enhancement of nondestructive testing from B‐scans
Authors: Shieh Hsin M. , Yu Hsin‐Chun , Hsu Yu‐Ching , Yu Ruei
Published: August 2012

This article presents an approach to extend our previous work of the minimum‐weighted norm method in computerized tomography. In particular concentrating on applications of ultrasonic nondestructive testing, the resolution enhancement in the image reconstruction from B‐scans is achieved. To combat the degradation problem due to physical focus of finite‐sized ultrasonic transducer and incompleteness of B‐scan data, a profile‐oriented prior knowledge about the object being detected is incorporated in the image reconstruction, in the form of weighted summation of specific basis functions. Each basis function is characterized by an image of coherent illumination pattern associated with a specific measuring time and a specific measuring position. From the demonstrations with both simulated and experimental data values, this technique proves a great potential in improving the image quality. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 185–193, 2012
COMPARING NEIGHBORHOOD‐FOCUSED ACTIVISM AND VOLUNTEERISM: PSYCHOLOGICAL WELL‐BEING AND SOCIAL CONNECTEDNESS
Authors: Gilster Megan E.
Published: August 2012

Does participating in neighborhood‐focused activism confer different benefits than volunteering? The engagement of community members in neighborhood civic life has been identified as an important component of safe and healthy communities. Research on community engagement has encompassed voluntary associations, volunteering, as well as participation in neighborhood activism. A diverse set of research suggests that there are psychological and social benefits to community engagement, but also suggests that there are differences between forms of participation. To understand these differences, I examine the relationship of both volunteerism and neighborhood activism to psychosocial outcomes using survey data from a neighborhood‐based sample of Chicago residents (n = 3105). Findings suggest that activism is different—activists have higher neighborhood and personal mastery than those who only volunteer. Participation in neighborhood activism is also associated with an increased likelihood of contact with local officials and social ties in the neighborhood. © 2012 Wiley Periodicals, Inc.
BUILDING THE YOUTH MENTORING KNOWLEDGE BASE: PUBLISHING TRENDS AND COAUTHORSHIP NETWORKS
Authors: Blakeslee Jennifer E. , Keller Thomas E.
Published: August 2012

Despite the long history and widespread popularity of youth mentoring, only in the past two decades has an academic literature emerged to support the development of program policies and practices. This study examines knowledge development in the field of youth mentoring, with special attention to trends in the number and nature of articles published in peer‐reviewed academic journals between 1990 and 2010. The analysis also represents this base of knowledge as a network of articles interconnected by patterns of co‐authorship. The co‐authorship network reveals a notable subset of scholars from several disciplines who are publishing frequently and collaboratively on the topic of youth mentoring. The existence of a core network of youth mentoring researchers bodes well for continued growth of the literature providing theoretical insight and empirical evidence on effective mentoring for youth.
RESIDENT WELL‐BEING, COMMUNITY CONNECTIONS, AND NEIGHBOURHOOD PERCEPTIONS, PRIDE, AND OPPORTUNITIES AMONG DISADVANTAGE METROPOLITAN AND REGIONAL COMMUNITIES: EVIDENCE FROM THE NEIGHBOURHOOD RENEWAL PROJECT
Authors: Renzaho André M.N. , Richardson Ben , Strugnell Claudia
Published: August 2012

The current study aims investigate the relationship between participants’ neighbourhood perceptions and social capital and resident well‐being using data from the Neighbourhood Renewal Project (NRP; n = 7855). Resident well‐being was positively associated with the quality of the physical environment and safety of the neighbourhood, but negatively associated with government trustworthiness and community connections. Life satisfaction had a positive relationship with community connections, resident well‐being, as well as quality of community services and safety. We conclude that free or low‐cost opportunities to engage and connect with neighbours through participation in activities such as sporting groups, volunteer organizations, and leisure/hobby groups may increase life satisfaction of individuals in a neighbourhood, particularly for those living in low socioeconomic or stigmatized areas.
CONTEXTUAL EFFECTS ON KINDERGARTEN TEACHERS’ INTENTION TO REPORT CHILD ABUSE
Authors: Feng Jui‐Ying , Wu Yow‐Wu B. , Fetzer Susan , Chang Hsin‐Yi
Published: August 2012

Child abuse is underreported for children with socioeconomic inequalities. The impact of geographic location combined with sociocultural characteristics on teachers’ reports of child abuse remains unclear. A national survey of 572 kindergarten teachers from 79 schools in Taiwan used hierarchical linear modeling to investigate the contribution of individual factors, environmental factors, and training on kindergarten teachers’ intention to report child abuse. In‐service training had the most influence on teachers’ intention to report in eastern Taiwan, the poorest and least‐educated region. Training programs should be designed based on socioeconomic and cultural contextual needs.
Carbon‐supported perovskite oxides as oxygen reduction reaction catalyst in single chambered microbial fuel cells
Authors: Dong Heng , Yu Hongbing , Wang Xin , Zhou Qixing , Sun Jingwen
Published: August 2012

BACKGROUND: Pt‐free cathodic catalyst is needed for microbial fuel cells (MFCs). Perovskite‐type oxide could be a substitute for Pt because it has been proved to be a highly active and low‐cost oxygen reduction catalyst in chemical fuel cells.

RESULTS: A nano‐sized La0.4Ca0.6Co0.9Fe0.1O3 perovskite‐type oxide on a carbon support (LCCF/C) was prepared and tested for its performance and stability (15 cycles) in MFCs. An exchange current density of 7.030 × 10−5 (A cm−2) was obtained with fresh LCCF/C cathode and is increased to 7.438 × 10−5 (A cm−2) after 15 cycles operating in MFCs. A power density of 405 mW m−2 was achieved with the LCCF/C cathode at the 2nd cycle which was between those of Pt/C (560 mW m−2) and C (339 mW m−2) cathodes. At the end of the 15th cycle, the lowest decay (due to biofouling) rate on the open circuit voltage (2%) and the maximum power density (15%) were observed with LCCF/C cathode compared with those of Pt/C (4%, 17%) and C (22%, 69%) cathodes, respectively.

CONCLUSIONS: This study demonstrated that perovskite‐type oxide on carbon support catalysts could be a potential substitute for Pt for cathodic oxygen reduction reaction (ORR) in air‐cathode MFCs. © 2012 Society of Chemical Industry
Fuel ethanol production fromEucalyptus globuluswood by autocatalized organosolv pretreatment ethanol–water and SSF
Authors: Yáñez‐S Mauricio , Rojas Jonathan , Castro Jean , Ragauskas Arthur , Baeza Jaime , Freer Juanita
Published: August 2012

BACKGROUND

Lignocellulosic biomass (LCB) offers the only sustainable alternative to the use of fossil fuels as oil by employing its main components (cellulose, hemicellulose and lignin) as a carbon source for the production of biofuels, energy and value‐added chemicals. The aim of the present study was to investigate ethanol production from organosolv pretreatedEucalyptus globuluswood, carrying out the simultaneous sacharification and fermentation (SSF) process at a substrate loading of 10 and 15% (w/v) and using concentrations of 6 and 12 g L−1of the thermally acclimatizedS. cerevisiaeIR2T9‐a strain. These SSF experiments were also evaluated by increasing the enzyme loading in the reaction medium. Finally, a comparison was made between separate hydrolysis and fermentation (SHF) and SSF processes. With the information obtained and from published information, a general mass balance was developed.

RESULTS

The highest ethanol concentration (∼42 g L−1) in the fermentation broth was obtained at a substrate consistency of 15% (w/v), enzyme loading of 20 FPU cellulase 40 UI β‐glucosidase g−1of pretreated material and using bothS. cerevisiaestrain IR2‐9a concentrations (6 and 12 g L−1).

CONCLUSION

The results of enzymatic hydrolysis (EH) show that increasing substrate content from 10 to 15% (w/v) decreases the conversion efficiency of cellulose to glucose. Furthermore, the mass balances of the process indicate that the SSF process is a better alternative than the SHF configuration, because larger amounts of ethanol can be obtained. Copyright © 2012 Society of Chemical Industry
Performance evaluation of an ANN–GA aided experimental modeling and optimization procedure for enhanced synthesis of marine biosurfactant in a stirred tank reactor
Authors: Sivapathasekaran Chandrasekaran , Sen Ramkrishna
Published: August 2012

BACKGROUND: An improved resilient back‐propagation neural network modeling coupled with genetic algorithm aided optimization technique was employed for optimizing the process variables to maximize lipopeptide biosurfactant production by marine Bacillus circulans.

RESULTS: An artificial neural network (ANN) was used to develop a non‐linear model based on a 24 full factorial central composite design involving four independent parameters, agitation, aeration, temperature and pH with biosurfactant concentration as the process output. The polynomial model was optimized to maximize lipopeptide biosurfactants concentration using a genetic algorithm (GA). The ranges and levels of these critical process parameters were determined through single‐factor‐at‐a‐time experimental strategy. Improved ANN‐GA modeling and optimization were performed using MATLAB v.7.6 and the experimental design was obtained using Design Expert v.7.0. The ANN model was developed using the advanced neural network architecture called resilient back‐propagation algorithm.

CONCLUSION: Process optimization for maximum production of marine microbial surfactant involving ANN‐GA aided experimental modeling and optimization was successfully carried out as the predicted optimal conditions were well validated by performing actual fermentation experiments. Approximately 52% enhancement in biosurfactant concentration was achieved using the above‐mentioned optimization strategy. © 2012 Society of Chemical Industry
Testing the Behavioural and Environmental Consistency of Serial Sex Offenders: A Signature Approach
Authors: Harbers Ellen , Deslauriers‐Varin Nadine , Beauregard Eric , van der Kemp Jasper J.
Published: August 2012

The present study examines consistency of crime behaviour among 347 sexual assaults committed by 69 serial sex offenders. This individual behaviour approach—the so‐called signature approach—reveals which features of crime behaviour are consistent across a series and which features are not. The consistency scores were calculated using the Jaccard's coefficient. The results of this study indicate that there are some crime features of a serial sexual assault that can be useful for the purpose of linkage. Another important finding is that consistency scores for different variables within the same category can differ substantially. Moreover, serial sex offenders are more likely to be consistent in their environmental crime features when they are also consistent in their behavioural features, and vice versa. Serial sex offenders are also more likely to be consistent in the behavioural features of their assaults as the crime series gets longer. The implications of the results are discussed in relation to both research and practise. Copyright © 2012 John Wiley & Sons, Ltd.
Evaluation of pressure‐driven brain infusions in nonhuman primates by intra‐operative 7 tesla MRI
Authors: Rosenbluth Kathryn H. , Martin Alastair J. , Bringas John , Bankiewicz Krystof S.
Published: August 2012

Purpose:

To characterize the effects of pressure‐driven brain infusions using high field intra‐operative MRI. Understanding these effects is critical for upcoming neurodegeneration and oncology trials using convection‐enhanced delivery (CED) to achieve large drug distributions with minimal off‐target exposure.

Materials and Methods:

High‐resolution T2‐weighted and diffusion‐tensor images were acquired serially on a 7 Tesla MRI scanner during six CED infusions in nonhuman primates. The images were used to evaluate the size, distribution, diffusivity, and temporal dynamics of the infusions.

Results:

The infusion distribution had high contrast in the T2‐weighted images. Diffusion tensor images showed the infusion increased diffusivity, reduced tortuosity, and reduced anisotropy. These results suggested CED caused an increase in the extracellular space.

Conclusion:

High‐field intra‐operative MRI can be used to monitor the distribution of infusate and changes in the geometry of the brain's porous matrix. These techniques could be used to optimize the effectiveness of pressure‐driven drug delivery to the brain. J. Magn. Reson. Imaging 2012; 36:1339–1346. © 2012 Wiley Periodicals, Inc.
Weidmüller, Inc., breaks away from the competition by creatively targeting customers' needs
Authors: White Doug , White Polly
Published: August 2012

One of management's ongoing challenges is how best to set its products and services apart from those of the competition—a task that takes on increasing importance in a troubled economy. For the president of Weidmüller, Inc., the American subsidiary of a German industrial manufacturer, that challenge led him to question prevailing assumptions about market segmentation in order to precisely identify the company's true customers. To address their particular needs, he devised a strategy to facilitate the purchasing process and created an incentive to encourage them to select his company's products over those of the competition. His efforts increased sales by 50 percent and distinguished Weidmüller as an industry trailblazer. © 2012 Wiley Periodicals, Inc.
Quality‐oriented teamwork resolves aerospace manufacturer's critical path tooling crisis
Authors: Gill Ronald A.
Published: August 2012

Faced with the loss of a supply of essential aircraft parts, an aerospace manufacturer took rapid steps to clarify and communicate the problem and organize a cross‐functional team of experts to address it. Working within a quality‐focused framework, they brainstormed a number of viable options and then systematically reviewed each to identify the one that would meet all production, cost, scheduling, and customer service requirements, while keeping all stakeholders abreast of developments. In the end, they redesigned critical processes so that the parts supply operation could be transferred to a local site at modest cost, thus ensuring uninterrupted production and the attainment of the company's financial and quality objectives. For its efforts, the team earned an International Team Excellence silver‐level award from the American Society for Quality in 2010. © 2012 Wiley Periodicals, Inc.
Why are some firms more innovative than others? Exploring the role of learning organization components
Authors: Farooq Omer
Published: August 2012

Basing their study on the seven‐component framework for a learning organization suggested by Marsick and Watkins in 2003, researchers investigated the combined as well as individual impact of these components on innovation in 139 South Asian companies. They also examined the effect that organizational size and type have on innovation. Their results revealed that the characteristics of learning organizations have a strong positive effect on the innovation performance of firms when they are combined, but that individually the components have no significant influence. In addition, they found that the effect differed depending on the size and type of organization. These findings have implications for organizational managers who wish to encourage innovation. © 2012 Wiley Periodicals, Inc.
Local versus regional processes: can soil characteristics overcome climate and fire regimes by modifying vegetation trajectories?
Authors: Genries Aurélie , Finsinger Walter , Asnong Hans , Bergeron Yves , Carcaillet Christopher , Garneau Michelle , Hély Christelle , Ali Adam A.
Published: August 2012

We analysed charcoal and pollen from sediments obtained from two lakes in the northwestern mixed‐wood Canadian boreal forest in order to reconstruct fire‐return intervals and vegetation dynamics over the last 8000 years. Sites were selected with contrasting soil properties (mesic versus dry‐sandy soils), allowing an estimation of the potential influence of soils on long‐term vegetation and fire dynamics. The sites likely experienced fewer fires during the period extending from 8000 to 4000 cal. a BP than over the last 4000 years. At both sites, eastern white pine (Pinus strobus) populations were most extensive shortly after deglaciation, with vegetation later shifting towards mixed woodlands with less P. strobus and more extensive Picea and Pinus banksiana populations. This gradual vegetation shift was probably induced by the establishment of colder and moister conditions along with a fire‐regime change. In spite of the parallel long‐term vegetation trajectories, vegetation composition differed between the two sites in both the past and present. Whereas Picea was more abundant at the mesic site, the fire‐adapted P. banksiana populations were more extensive at the sandy‐soil site. These differences in vegetation composition indicate that, in addition to climate changes and fire occurrence, soil properties also influenced vegetation dynamics. A likely increase in fire frequency in the Canadian boreal forest during the 21st century might therefore favour the expansion of these two disturbance‐adapted trees with spatial heterogeneity in the populations due to varying soil types. Copyright © 2012 John Wiley & Sons, Ltd.
Sulfate determines the glucosinolate concentration of horseradish in vitro plants (Armoracia rusticana Gaertn., Mey. & Scherb.)
Authors: Alnsour Mohammad , Kleinwächter Maik , Böhme Julia , Selmar Dirk
Published: August 2012

BACKGROUND: Horseradish plants (Armoracia rusticana) contain high concentrations of glucosinolates. Former studies have revealed that Armoracia plants cultivated in vitro have markedly lower glucosinolate concentrations than those grown in soils. Yet, these studies neglected that the sulfate concentration in the growth medium may have had a strong impact on glucosinolate metabolism. Accordingly, in this study horseradish in vitro plants were cultivated with differing sulfate concentrations and the glucosinolate concentrations were quantified by ion pair HPLC.

RESULTS: Cultivation in 1.7 mmol L−1 sulfate (as used in the prior studies) resulted in the accumulation of 16.2 µmol g−1 DW glucosinolates, while the glucosinolate concentration increased to more than 23 µmol g−1 DW when 23.5 mmol L−1 sulfate was used in the medium. Correspondingly, the glucosinolate concentration decreased to 1.6 µmol g−1 DW when sulfate concentration was lowered to 0.2 mmol L−1.

CONCLUSION: Since the glucosinolate accumulation in relation to the sulfate concentration follows a typical saturation curve, we deduce that the availability of sulfate determines the glucosinolate concentration in horseradish in vitro plants. © 2012 Society of Chemical Industry
Fingerprinting and simultaneous determination of alkaloids in Picrasma quassioides from different locations by high performance liquid chromatography with photodiode array detection
Authors: Liao Hui‐Jun , Lai Zheng‐Quan , Su Ji‐Yan , Yi Yu‐Yang , Li Yu‐Cui , Lai Xiao‐Ping , Su Zi‐Ren , Lin Zhi‐Xiu
Published: August 2012

A simple and sensitive method was developed and validated for profiling and simultaneous quantitation of seven alkaloids (6‐hydroxy‐β‐carboline‐1‐carboxylic acid, β‐carboline‐1‐carboxylic acid, β‐carboline‐1‐propanoic acid, 3‐methylcanthin‐5,6‐dione, 5‐hydroxy‐4‐methoxycanthin‐6‐one, 1‐methoxycarbony‐β‐carboline, and 4,5‐dimethoxycanthin‐6‐one) in Picrasma quassioide grown in different locations by high‐performance liquid chromatography with photodiode array detection. The analysis was conducted on a Phenomenex Gemini C18 column at 35°C with mobile phase of 25 mM aqueous ammonium acetate (pH 4.0, adjusted by glacial acetate acid) and acetonitrile. A common fingerprint chromatograph under 254 nm consisting of 27 peaks was constructed for the evaluation of the similarities among 31 P. quassioide samples. Samples from Guangdong and Guangxi Provinces were found to be within group linkage and showed significant difference from that of Jiangxi Province origin by using principal component analysis and hierarchical clustering analysis. In addition, the seven alkaloids were identified by electrospray ionization mass spectrometry and comparing with reference standards and literature data. All of them were determined simultaneously using the established HPLC method. This rapid and effective analytical method could be employed for quality assessment of P. quassioide, as well as pharmaceutical products containing this herbal material.
Single and binary adsorption of proteins on ion‐exchange adsorbent: The effectiveness of isothermal models
Authors: Liang Juan , Fieg Georg , Shi Qing‐Hong , Sun Yan
Published: August 2012

Simultaneous and sequential adsorption equilibria of single and binary adsorption of bovine serum albumin and bovine hemoglobin on Q Sepharose FF were investigated in different buffer constituents and initial conditions. The results in simultaneous adsorption showed that both proteins underwent competitive adsorption onto the adsorbent following greatly by protein–surface interaction. Preferentially adsorbed albumin complied with the universal rule of ion‐exchange adsorption whereas buffer had no marked influence on hemoglobin adsorption. Moreover, an increase in initial ratios of proteins was benefit to a growth of adsorption density. In sequential adsorption, hemoglobin had the same adsorption densities as single‐component adsorption. It was attributed to the displacement of preadsorbed albumin and multiple layer adsorption of hemoglobin. Three isothermal models (i.e. extended Langmuir, steric mass‐action, and statistical thermodynamic (ST) models) were introduced to describe the ion‐exchange adsorption of albumin and hemoglobin mixtures. The results suggested that extended Langmuir model gave the lowest deviation in describing preferential adsorption of albumin at a given salt concentration while steric mass‐action model could very well describe the salt effect in albumin adsorption. For weaker adsorbed hemoglobin, ST model was the preferred choice. In concert with breakthrough data, the research further revealed the complexity in ion‐exchange adsorption of proteins.
Optimization of ultrasonic‐assisted extraction of 3‐monochloropropane‐1,2‐diol (MCPD) and analysis of its esters from edible oils by gas chromatography–mass spectrometry
Authors: Ma Fei , Li Peiwu , Matthäus Bertrand , Zhang Wen , Zhang Qi
Published: August 2012

In this paper, ultrasonic‐assisted extraction of 3‐chloropropane‐1,2‐diol and its esters from edible oils was studied with isotope dilution GC‐MS. Effects of several experimental parameters, such as types and concentrations of extracting solvent, ratios of liquid to material, extraction temperature, time of ultrasonic treatment on the extraction efficiency of 3‐chloropropane‐1,2‐diol and its esters from edible oils and sample preparation for calibration were compared and optimized. The optimal extraction conditions were suggested as 66 mg oil sample in mixture of 0.5 mL MTBE/ethyl acetate (20% v/v) and 0.5 mL of sulfuric acid/n‐propanol (0.3% v/v), being extracted for 30 min at 45°C under ultrasonic irradiation. Good linearity was gained in the range of 0.020–5.000 μg/g with the limit of detection (LOD) of 0.006 μg/g (S/N = 3) and the limit of quantification (LOQ) of 0.020 μg/g (S/N = 10). The recoveries at five spiked concentrations were ranged from 91.9 to 109.3% with RSD less than 9.4%. The method was successfully applied to the determination of 3‐chloropropane‐1,2‐diol and its esters amounts in rapeseed, sesame, peanut, camellia, and soybean oils.
In vitro and in vivo Antitumor Activity of Doxorubicin‐Loaded Alginic‐Acid‐Based Nanoparticles
Authors: Cheng Yuan , Yu Shuling , Wang Jingjing , Qian Hanqing , Wu Wei , Jiang Xiqun
Published: August 2012

The antitumor activities of DOX‐loaded alginic acid/poly[2‐(diethylamino)ethyl methacrylate] (ALG‐PDEA) nanoparticles are evaluated both in vitro and in vivo. TEM imaging shows that the ALG‐PDEA NPs have a spherical morphology with a size of about 120 nm. CLSM observations reveal that the negatively charged ALG‐PDEA NPs can be taken up well by cells. In vivo NIR fluorescence imaging shows that the ALG‐PDEA NPs can passively target the tumor area because of the EPR effect in the H22 tumor‐bearing mouse. In vivo antitumor efficacy examinations indicate that DOX‐loaded ALG‐PDEA NPs have significantly superior efficacy in impeding tumor growth compared to free DOX and low toxicity to living mice.

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Head Group Influence on Lipid Interactions With a Polyhydroxyalkanoate Biopolymer
Authors: Jagoda Agnieszka , Zinn Manfred , Meier Wolfgang , Kita‐Tokarczyk Katarzyna
Published: August 2012

Poly([R]‐3‐hydroxy‐10‐undecenoate) (PHUE) is a biodegradable/biocompatible polyester from polyhydroxyalkanoates (PHAs) family, used in biomedical applications. PHA's introduction to the body may have implications on cell membrane stability—this motivates studies of interactions between PHAs and phospholipids, main membrane constituents. Interaction analysis in PHUE monolayers with two phospholipids (different hydrophilic groups), phosphatidylserine (DOPS), and phosphatidylethanolamine (DOPE), shows that repulsive interactions between PHUE and DOPS and attractive between PHUE and DOPE resulted from different lipid headgroup size and orientation at the air–water interface (PE, parallel to the interface, attracted PHUE via hydrogen bonds, ion–dipole, and dipole–dipole interactions).
Aqueous RAFT Polymerization ofN‐Acryloylmorpholine, Synthesis of an ABA Triblock Glycopolymer and Study of its Self‐Association Behavior
Authors: Albertin Luca , Wolnik Anna , Ghadban Ali , Dubreuil Frédéric
Published: August 2012

The RAFT polymerization ofN‐acryloylmorpholine with a symmetric trithiocarbonate was investigated in homogeneous aqueous solution. The effects of temperature and of a high magnetic field were examined and RAFT experiments were compared with the corresponding conventional radical polymerizations. For all temperatures tested, the molar mass of the polymer increased linearly with conversion and closely matched the theoretical value. Molar mass dispersities were in the range 1.05–1.16 and the presence of a magnetic field had little effect on the rate of RAFT polymerizations, although the latter were systematically slower than the corresponding conventional processes. A uniform ABA triblock glycopolymer was prepared, which formed unilamellar polymersomes with a diameter of 380 nm in 91% (v/v) THF/water mixture.
Thermoresponsive Poly(2‐Oxazoline) Molecular Brushes by Living Ionic Polymerization: Modulation of the Cloud Point by Random and Block Copolymer Pendant Chains
Authors: Zhang Ning , Luxenhofer Robert , Jordan Rainer
Published: August 2012

Molecular brushes (MBs) of poly(2‐oxazoline)s were prepared by living anionic polymerization of 2‐isopropenyl‐2‐oxazoline to form the backbone and living cationic ring‐opening polymerization of 2‐n‐propyl‐2‐oxazoline and 2‐methyl‐2‐oxazoline to form random and block copolymers. Their aqueous solutions displayed a distinct thermoresponsive behavior as a function of the side‐chain composition and sequence. The cloud point (CP) of MBs with random copolymer side chains is a linear function of the hydrophilic monomer content and can be modulated in a wide range. For MBs with block copolymer side chains, it was found that the block sequence had a strong and surprising effect on the CP. While MBs with a distal hydrophobic block had a CP at 70 °C, MBs with hydrophilic outer blocks already precipitated at 32 °C.
Poly(2‐oxazoline) Hydrogel Monoliths via Thiol‐ene Coupling
Authors: Dargaville Tim R. , Forster Rebecca , Farrugia Brooke L. , Kempe Kristian , Voorhaar Lenny , Schubert Ulrich S. , Hoogenboom Richard
Published: August 2012

Copoly(2‐oxazoline)s, prepared by the cationic ring‐opening polymerization of 2‐(dec‐9‐enyl)‐2‐oxazoline with either 2‐methyl‐2‐oxazoline or 2‐ethyl‐2‐oxazoline, are crosslinked with small dithiol molecules under UV irradiation to form homogeneous networks. In situ monitoring of the crosslinking reaction by photo‐rheology reveals the formation of soft gels within minutes. The degree of swelling in water is tunable based on the hydrophilicity of the starting macromers and the proportion of alkene side arms present. Furthermore, degradable hydrogels are prepared based on incorporation of a hydrolytically cleavable dithiol crosslinker. The rapid synthesis of the macromers and mild crosslinking conditions make these materials ideal for future biomaterial applications.
Polymeric Biomaterials for Stem Cell Bioengineering
Authors: Prewitz Marina , Seib Friedrich Philipp , Pompe Tilo , Werner Carsten
Published: August 2012

This review covers the application of polymeric materials in stem cell bioengineering. Main emphasis is directed towards current material design concepts that mimic distinct exogenous signals of the stem cell microenvironment. Progress within the field of stem cell‐specific biomaterials will be discussed, focusing on pluripotent, hematopoietic, mesenchymal and neural stem cells. The future role of biomaterials will be outlined with possible applications for cell reprogramming and engineering cancer cell microenvironments.
SARConnect: A Tool to Interrogate the Connectivity Between Proteins, Chemical Structures and Activity Data
Authors: Eriksson Mats , Nilsson Ingemar , Kogej Thierry , Southan Christopher , Johansson Martin , Tyrchan Christian , Muresan Sorel , Blomberg Niklas , Bjäreland Marcus
Published: August 2012

The access and use of large‐scale structure‐activity relationships (SAR) is increasing as the range of targets and availability of bioactive compound‐to‐protein mappings expands. However, effective exploitation requires merging and normalisation of activity data, mappings to target classifications as well as visual display of chemical structure relationships. This work describes the development of the application “SARConnect” to address these issues. We discuss options for delivery and analysis of large‐scale SAR data together with a set of use‐cases to illustrate the design choices and utility. The main activity sources of ChEMBL,1 GOSTAR2 and AstraZeneca’s internal system IBIS, had already been integrated in Chemistry Connect.3 For target relationships we selected human UniProtKB/Swiss‐Prot4 as our primary source of a heuristic target classification. Similarly, to explore chemical relationships we combined several methods for framework and scaffold analysis into a unified, hierarchical classification where ease of navigation was the primary goal. An application was built on TIBCO Spotfire to retrieve data for visual display. Consequently, users can explore relationships between target, activity and structure across internal, external and commercial sources that encompass approximately 3 million compounds, 2000 human proteins and 10 million activity values. Examples showing the utility of the application are given.
Annotating Human P‐Glycoprotein Bioassay Data
Authors: Zdrazil Barbara , Pinto Marta , Vasanthanathan Poongavanam , Williams Antony J. , Balderud Linda Zander , Engkvist Ola , Chichester Christine , Hersey Anne , Overington John P. , Ecker Gerhard F.
Published: August 2012

Huge amounts of small compound bioactivity data have been entering the public domain as a consequence of open innovation initiatives. It is now the time to carefully analyse existing bioassay data and give it a systematic structure. Our study aims to annotate prominent in vitro assays used for the determination of bioactivities of human P‐glycoprotein inhibitors and substrates as they are represented in the ChEMBL and TP‐search open source databases. Furthermore, the ability of data, determined in different assays, to be combined with each other is explored. As a result of this study, it is suggested that for inhibitors of human P‐glycoprotein it is possible to combine data coming from the same assay type, if the cell lines used are also identical and the fluorescent or radiolabeled substrate have overlapping binding sites. In addition, it demonstrates that there is a need for larger chemical diverse datasets that have been measured in a panel of different assays. This would certainly alleviate the search for other inter‐correlations between bioactivity data yielded by different assay setups.
Calcium signaling in mammalian egg activation and embryo development: The influence of subcellular localization
Authors: Miao Yi‐Liang , Williams Carmen J.
Published: August 2012

Calcium (Ca2+) signals drive the fundamental events surrounding fertilization and the activation of development in all species examined to date. Initial studies of Ca2+ signaling at fertilization in marine animals were tightly linked to new discoveries of bioluminescent proteins and their use as fluorescent Ca2+ sensors. Since that time, there has been rapid progress in our understanding of the key functions for Ca2+ in many cell types and of the impact of cellular localization on Ca2+ signaling pathways. In this review, which focuses on mammalian egg activation, we consider how Ca2+ is regulated and stored at different stages of oocyte development and examine the functions of molecules that serve as both regulators of Ca2+ release and effectors of Ca2+ signals. We then summarize studies exploring how Ca2+ directs downstream effectors mediating both egg activation and later signaling events required for successful preimplantation embryo development. Throughout this review, we focus attention on how localization of Ca2+ signals influences downstream signaling events, and attempt to highlight gaps in our knowledge that are ripe for future research. Mol. Reprod. Dev. 79: 742–756, 2012. Published 2012. This article is a US government work and, as such, is in the public domain in the United States of America.