bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel population balance model to investigate the kinetics of in vitro cell proliferation: Part I. model development
Authors: Fadda Sarah , Cincotti Alberto , Cao Giacomo
Published: October 2011

In biotechnology and biomedicine reliable models of cell proliferation kinetics need to capture the relevant phenomena taking place during the mitotic cycle. To this aim, a novel mathematical model helpful to investigate the intrinsic kinetics of in vitro culture of adherent cells up to confluence is proposed in this work. Specifically, the attention is focused on the simulation of proliferation (increase of cell number) and maturation (increase of cell size and DNA content) till contact inhibition eventually takes place inside a Petri dish. Accordingly, the proposed model is based on a population balance (PB) approach that allows one to quantitatively describe cell cycle progression through the different phases the cells of the entire population experienced during their own life. In particular, the proposed model has been developed as a 2D, multi‐staged, and unstructured PB, by considering a different sub‐population of cells for any single phase of the cell cycle. These sub‐populations are discriminated through cellular volume and DNA content, that both increase during the mitotic cycle. The adopted mathematical expressions of the transition rates between two subsequent phases and the temporal increase of cell volume and DNA content are thoroughly analyzed and discussed with respect to those ones available in the literature. Specifically, the corresponding uncertainties and pitfalls are pointed out, by also taking into account the difficulties and the limitations involved in the quantitative measurements currently practicable for these biological systems. A novel mathematical expression for contact inhibition in line with the PB model developed is also formulated, along with a proper comparison between modeled and measurable DNA distributions. The strategy for a reliable, independent tuning of the adjustable parameters involved in the proposed model along with its numerical solution is outlined in Part II of this work, where it is also shown how it can be profitably used to gain a deeper insight into the phenomena involved during cell cultivation under microgravity conditions. Biotechnol. Bioeng. 2012; 109:772–781. © 2011 Wiley Periodicals, Inc.
Stability of Uni‐ and Multillamellar Spherical Vesicles
Authors: Tayebi Lobat , Vashaee Daryoosh , Parikh Atul N.
Published: October 2011

Lipid molecules in water form uni‐ or multilamellar vesicles in polydisperse form. Herein, we present energetic considerations for their equilibrium morphological organization. Our formulation provides elemental energy diagrams, which explain the polydispersity and account for the structural diversity. These energy diagrams describe the ranges of core radius (rc) and number of lamellae (N) that result in the formation of stable vesicles under specific conditions, thus providing prescriptions for the design of vesicles tailored for specific properties, including stability, cargo capacity, and resistance to deformation by osmotic stress. We deduced key design criteria as follows: 1) designing highly stable unilamellar vesicles requires low bending rigidity lipids and dimensions exceeding a few hundred nm in radii; 2) very large unilamellar vesicles (rc>several tens of microns) are not stable for typical lipids; lipids with higher bending rigidity are required; 3) the distribution of the stable size of vesicles is proportional to the bending rigidity; 4) for the case of multilamellar vesicles, vesicles with more than a few hundred layers usually exhibit greater structural integrity than those with lower degrees of lamellarity, especially when the core radii are small (<100 nm); 5) for osmotically stressed vesicles, the energy contributed by even a small concentration gradient (>mM) is the most dominant factor in the free energy, suggesting active response by vesicles (e.g., poration) to release osmotic stress; and 6) vesicles with a core radius of a few hundred nm and more than hundred lamellae are more resistant to deformation by osmotic stress, thus making them more suited to applications involving osmotic pressure gradients, such as in drug delivery.
Urinary excretion of exogenous glycerol administration at rest
Authors: Koehler Karsten , Braun Hans , de Marees Markus , Geyer Hans , Thevis Mario , Mester Joachim , Schaenzer Wilhelm
Published: October 2011

Since 2010, glycerol has been ruled a masking agent by the World Anti‐Doping Agency and consequently its administration is prohibited in sports. A detection method is available but little is known about the urinary excretion following administration.

Fourteen well‐trained cyclists (27.0 ± 5.4 years; O2max: 63.9 ± 8.5 ml/kg/min) were administered glycerol (1 g/kg body mass + 25 ml water/kg body mass) and placebo (25 ml water/kg) in a cross‐over study. Blood and urine samples were collected before administration and after 2.5, 4, and 6.5 h. Urine samples were further collected up to 24 h post‐administration.

Following glycerol administration, urinary glycerol increased from 10.9 ± 15.5 to 50581 ± 23821 µg/ml within 2.5 h. In the placebo group, urinary glycerol did not exceed 26.8 ± 31.3 µg/ml. Urinary concentrations in the glycerol group were significantly higher than in the placebo group for 16.9 ± 1.0 h.

In comparison to placebo, glycerol caused a larger increase in body weight (0.69 ± 0.42 vs. 0.27 ± 0.44 kg; p < 0.05) and a reduced urine output (972 ± 379 vs. 1271 ± 387 ml; p < 0.05). Reductions in haemoglobin and haematocrit were significantly greater after glycerol (−0.60 ± 0.28 g/dl; ‐1.7 ± 0.7%) than after placebo administration (−0.29 ± 0.39 g/dl; ‐0.9 ± 1.1%).

The study shows that glycerol administration was detectable in urine for several hours. Even though there were significant reductions in haemoglobin and haematocrit after 2.5 h, the plasma expansion by glycerol appeared rather marginal in comparison to placebo. Copyright © 2011 John Wiley & Sons, Ltd.
Axonemal positioning and orientation in three‐dimensional space for primary cilia: What is known, what is assumed, and what needs clarification
Authors: Farnum Cornelia E. , Wilsman Norman J.
Published: October 2011

Two positional characteristics of the ciliary axoneme—its location on the plasma membrane as it emerges from the cell, and its orientation in three‐dimensional (3D) space—are known to be critical for optimal function of actively motile cilia (including nodal cilia), as well as for modified cilia associated with special senses. However, these positional characteristics have not been analyzed to any significant extent for primary cilia. This review briefly summarizes the history of knowledge of these two positional characteristics across a wide spectrum of cilia, emphasizing their importance for proper function. Then the review focuses what is known about these same positional characteristics for primary cilia in all major tissue types where they have been reported. The review emphasizes major areas that would be productive for future research for understanding how positioning and 3D orientation of primary cilia may be related to their hypothesized signaling roles within different cellular populations. Developmental Dynamics 240:2405–2431, 2011. © 2011 Wiley Periodicals, Inc.
A focal adhesion protein‐based mechanochemical checkpoint regulates cleft progression during branching morphogenesis
Authors: Daley William P. , Kohn Joshua M. , Larsen Melinda
Published: October 2011

E13 mouse submandibular salivary gland (SMG) cultured for 24 hours ex vivo and immunostained for collagen IV (blue) to mark the basement membrane, Na+/K+ ATPase (green) which is preferential for the epithelium, and the focal adhesion protein vinculin (red) to delineate cell‐matrix adhesions. Note that vinculin localizes the most strongly to regions of cell‐matrix contact immediately adjacent to the basement membrane. From Daley et al., Developmental Dynamics 240:2069–2083, 2011.
Portraits of Porosity: Porous Structures Based on Metal Salen Complexes
Authors: Crane Angela K. , MacLachlan Mark J.
Published: October 2011

Metal complexes based on the salen ligand are highly versatile compounds that have many interesting properties, including magnetism, catalysis, and reversible oxygen binding. The marriage of complexes of salen with porous materials is a promising way to combine the attractive properties of the salen complex with those of the porous structure. In this Microreview, we discuss several recent examples of published research that illustrate the power of combining these two disparate areas of research. Approaches based on supramolecular chemistry are emphasized.
Solid‐phase extraction‐field‐amplified sample injection coupled with CE‐ESI‐MS for online pre‐concentration and quantitative analysis of brain‐gut peptides
Authors: Ye Hongzhi , Xia Shifei , Yu Lishuang , Xu Xueqin , Zheng Chunsong , Xu Huifeng , Wang Lili , Liu Xianxiang , Cai Zongwei , Chen Guonan
Published: October 2011

In order to improve the sensitivity of CE‐ESI‐MS for the analysis of brain‐gut peptides, a solid‐phase extraction combined with field‐amplified sample injection was used for the pre‐concentration of the brain‐gut peptides. Compared with the conventional pressure injection method, the sensitivity in the detection of brain‐gut peptides was improved more than 100‐fold. The possible factors affecting sample stacking, such as the sample matrix, the composition and the length of the water column, the types and the volumes of eluent, have been investigated in detail. Under the optimum conditions, the detectable concentration of brain‐gut peptides was found to be as low as 0.02 μM. A linear response concentration for the detection was developed in the range of 0.08–25 μmol/L. A real sample of human cerebrospinal fluids, which was spiked with brain‐gut peptides, was also examined in order to evaluate the reliability of the proposed approach. The recovery of the method was in a range from 69.2 to 85.4%. The method was found to be reliable, accurate and potentially applicable for clinical drug analysis.
Classification of power system voltage stability conditions using Kohonen's self‐organising feature map and learning vector quantisation
Authors: De Abhinandan , Chakraborty Kabir , Chakrabarti Abhijit
Published: October 2011

This paper presents an artificial neural network–based approach, in which Kohonen's self‐organising feature map technique in association with learning vector quantisation has been applied to classify the power system operating states on the basis of their degree of static voltage stability. The proposed scheme can seamlessly integrate itself within the energy management systems in the smart grid scenario. A self‐organising feature map has been considered to be an ideal choice because the state classification problem is a typical multiclass pattern classification problem, which can be efficiently handled by a self‐organising feature map with much shorter training time compared with other neural networks. The self‐organising feature map provided information about the operating states of the power system and classified them into three categories, namely, normal state, intermediate state and emergency (or alert) state. To augment the classification accuracy of self‐organising feature map, a learning vector quantisation–based supervised classification was also adopted. The proposed method was tested on a real 203‐bus system of an Indian power utility, and the results obtained has been compared with standard voltage stability indicator–based classical voltage stability assessment results. Copyright © 2011 John Wiley & Sons, Ltd.
A stream function–vorticity formulation‐based immersed boundary method and its applications
Authors: Ren W. W. , Wu J. , Shu C. , Yang W. M.
Published: October 2011

A new stream function–vorticity formulation‐based immersed boundary method is presented in this paper. Different from the conventional immersed boundary method, the main feature of the present model is to accurately satisfy both governing equations and boundary conditions through velocity correction and vorticity correction procedures. The velocity correction process is performed implicitly based on the requirement that velocity at the immersed boundary interpolated from the corrected velocity field accurately satisfies the nonslip boundary condition. The vorticity correction is made through the stream function formulation rather than the vorticity transport equation. It is evaluated from the firstorder derivatives of velocity correction. Two simple and efficient ways are presented for approximation of velocity‐correction derivatives. One is based on finite difference approximation, while the other is based on derivative expressions of Dirac delta function and velocity correction. It was found that both ways can work very well. The main advantage of the proposed method lies in its simple concept, easy implementation, and robustness in stability. Numerical experiments for both stationary and moving boundary problems were conducted to validate the capability and efficiency of the present method. Good agreements with available data in the literature were achieved. Copyright © 2011 John Wiley & Sons, Ltd.
Effect of temporal resolution of hydrological data on annual canopy evaporation derived from a simple interception model
Authors: Lu Minjiao
Published: October 2011

The objective of this study was to investigate the effect of the temporal resolution of hydrological data on an interception simulation. Hydrological data with different temporal resolutions generated from a 28‐year hourly hydrological data set was applied to a simple interception model. The effect was significant and was quantified by a newly developed formula that relates the annual canopy evaporation with the annual effective potential evaporation, canopy capacity and temporal resolution. Using this formula, the true annual canopy evaporation invariant to the temporal resolution can be derived from the annual effective potential evaporation and canopy capacity. The concept of an operational parameter value and its calculation algorithm was proposed. The operational parameter values corresponding to their true values and the temporal resolutions were used in the model operation with the hydrological data of the same resolution, and the true annual canopy evaporation was reproduced very well. This implies the necessity of using operational parameters according to temporal resolution of the data in a hydrological simulation. Copyright © 2011 John Wiley & Sons, Ltd.
Spatial lumping of a distributed rainfall‐sediment‐runoff model and its effective lumping scale
Authors: Apip  , Sayama Takahiro , Tachikawa Yasuto , Takara Kaoru
Published: October 2011

This paper proposes a method to spatially lump a distributed rainfall‐sediment‐runoff model at the catchment scale. Based on a kinematic wave rainfall‐sediment‐runoff model, the proposed method spatially integrates (1) a rainfall‐runoff model that simulates unsaturated, saturated subsurface and surface runoff processes and (2) a rainfall‐sediment‐runoff model that simulates soil erosion and transport processes induced by raindrops and surface flow detachment, respectively. The method deductively derives a set of lumped equations that relates the streamflow discharge and the catchment storage of water and sediment, which are then used together with continuity equations to predict the sediment runoff fluxes from the catchment outlet. The main advantage of the method is that the derived lumped model parameters are reflected by the spatially distributed topographical and soil property information, and yet the model can be implemented with a much less computational load compared to the original distributed model. Thus, the model gives a possibility of its numerous applications − such as the application to real‐time flood forecasting, sediment yield‐flood prediction for hydraulical structure designing, and for a climate change impact analysis on hydrological responses − coupled with the risk and uncertainty analyses which require a number of simulations. The developed lumped model successfully simulated the original distributed model outputs, as well as the observed streamflow and sediment at the Lesti River Catchment (381 km2), a tributary of the Brantas River Basin in Indonesia. After validating the proposed lumped model, the most effective lumping scale was then investigated by conducting multiple simulations, the results of which suggested that approximately 200 km2 is the ideal lumping scale for this model. Copyright © 2011 John Wiley & Sons, Ltd.
Catchment responses to plausible parameters and input data under equifinality in distributed rainfall‐runoff modeling
Authors: Lee Giha , Tachikawa Yasuto , Sayama Takahiro , Takara Kaoru
Published: October 2011

In a hydrological simulation using a complex model, equifinality is likely to occur in many different ways, due to various sources associated with the model structure, parameter as well as data uncertainties involved in modeling process. This study aims to demonstrate the equifinality problem in streamflow prediction with a distributed rainfall‐runoff model and also investigate the effect of parameter and input uncertainties on an internal catchment response in time and space under the equifinality condition. For this objective, several experiments were carried out step by step as follows. First, we estimated plausible parameter sets, which lead to similarly good objective function values, using the shuffled complex evolution metropolis (SCEM‐UA) algorithm and also generated plausible input scenarios with different spatial patterns from radar rainfall field, which showed minimum runoff errors. Then, we adopted a computational tracer method based on a time‐space accounting scheme, combined with a distributed model for analyzing how a catchment behaves under a given equifinality condition by parameter and input uncertainties. It was found that the global responses of a catchment to the predefined equifinality factors were very similar; all simulated hydrographs were almost identical in spite of the different model parameter values and different spatial patterns of rainfall data. On the other hand, the internal catchment responses, tracked by the computational tracer method, were sensitive to plausible scenarios. The results of the internal catchment behavior show that the distributed rainfall‐runoff model has multiple alternative flow pathways, providing identical hydrographs in time and space when the rainfall over the catchment transforms into runoff. Our approach can be used to understand catchment responses to various uncertainty sources by visualizing the spatiotemporal runoff generation process at the watershed scale. Copyright © 2011 John Wiley & Sons, Ltd.
A statistically based runoff‐yield model coupling infiltration excess and saturation excess mechanisms
Authors: Liang Zhongmin , Wang Jun , Li Binquan , Yu Zhongbo
Published: October 2011

A statistically based runoff‐yield model is proposed in this paper. The model considers spatial heterogeneities of rainfall, soil infiltration capacity and soil water storage capacity that are main factors controlling runoff‐yield process. It assumes that the spatial variation of rainfall intensity at each time step can be characterized by a probability density function, which is estimated by matching the hyetograph through goodness‐of‐fit measure, whereas the spatial heterogeneities of soil infiltration capacity and soil water storage capacity are described by parabola‐type functions. Surface runoff is calculated according to infiltration excess mechanism; the statistical distribution of surface runoff rate can be deduced with the joint distribution of rainfall intensity and soil infiltration rate, thus obtaining a quasi‐analytical solution for surface runoff. Based on saturation excess mechanism, the groundwater flow (flows below the ground are collectively referred to as groundwater flow) is calculated by infiltration and the probability distribution of soil water storage capacity. Consequently, the total runoff is composed of infiltration excess and saturation excess runoff components. As an example, this model is applied to flood event simulation in Dongwan catchment, a semi‐humid region and a tributary of Yellow River in China. It indicates that the proposed runoff‐yield model could achieve acceptable accuracy. Copyright © 2011 John Wiley & Sons, Ltd.
Detection of distinct human immunodeficiency virus Type 1 circulating recombinant forms in Northeast Brazil
Authors: Santos Luciane Amorim , Monteiro‐Cunha Joana Paixao , Araujo Adriano Fernando , Brites Carlos , Galvao‐Castro Bernardo , Alcantara Luiz Carlos Junior
Published: October 2011

The extraordinary genetic diversity and immune evasion of human immunodeficiency virus (HIV) pose significant challenges for vaccine development and antiretroviral therapy efficacy. The objective of this study was to characterize the molecular profile of HIV‐1 epidemic in Salvador, Bahia, Brazil, determining the genetic subtypes and the presence of antiretroviral resistance mutations. HIV‐1 pol DNA sequences from 57 individuals infected with HIV were obtained by PCR, followed by sequencing. The subtypes were determined by phylogenetic analyses and the intersubtype recombination was investigated by bootscanning. The pol subtypes were compared with gag and env subtypes. Antiretroviral susceptibility was evaluated through the Stanford HIV resistance Database. The subtypes frequencies were: 77.2% of subtype B, 1.8% of subtype F1, and 21.0% of BF recombinant forms. Two intergenic and three intragenic BF recombinant patterns were observed. Six (10.5%) viruses were related to CRF28/CRF29, two were related to CRF12 (3.5%), and one (1.8%) was CRF39. Fourteen (24.6%) strains carried one or more mutations associated with at least intermediate resistance: 24.6% had resistance to nucleoside reverse transcriptase inhibitors, 21.0% to non‐nucleoside reverse transcriptase inhibitors, and 7% to protease inhibitors. The substitutions I54V (7.0%), M184V (14.0%), and K103N (10.5%) were the most frequent within each class of drugs. The results show a high diversity of BF genotypes and a lower prevalence of major reverse transcriptase and protease drug resistance mutations in Salvador, compared with other regions of Brazil. These findings may contribute to improve treatment strategies of patients infected with HIV‐1 from this Brazilian region. J. Med. Virol. 83:2066–2072, 2011. © 2011 Wiley Periodicals, Inc.
Transmission of Hepatitis C virus among spouses in Cameroon and the Central African Republic
Authors: Njouom Richard , Lavoie Myriam , Foupouapouognigni Yacouba , Frost Eric , Deslandes Sylvie , Mamadou‐Yaya Fleurie , Mbélesso Pascal , Mbadingai Sylvestre , Pépin Jacques
Published: October 2011

Heterosexual transmission of hepatitis C virus (HCV) is uncommon, with few studies undertaken in Central Africa. To determine the frequency of inter‐spouse HCV transmission, cross‐sectional studies of elderly individuals in Ebolowa, Cameroon and Nola, Central African Republic, in which, respectively, 24 and 83 long‐term couples had been identified, were examined further. Blood samples were tested for antibody to HCV. Anti‐HCV positive samples were genotyped by phylogenetic analysis of a fragment of the NS5B gene. In Nola, 4 out of 9 (44.4%) wives of anti‐HCV positive husbands and 1 out of 74 (1.4%) wives of anti‐HCV negative husbands were anti‐HCV positive (P < 0.001); in Ebolowa, the corresponding proportions were 10 out of 15 (66.7%) and 3 out of 9 (33.3%) (P = 0.21). After adjustment for age and site‐specific risk factors of HCV infection, HCV seropositivity of the wives remained associated with their husbands' HCV serostatus, significantly so in Nola (P = 0.003) and marginally in Ebolowa (P = 0.06). In 7 out of 14 concordant seropositive couples, the genotype could be determined in both spouses. Four couples were infected with different genotypes, while three were infected with the same genotype. Thus, serological concordance between the spouses was related to a combination of infections acquired independently and inter‐spouse transmission. It could not be determined whether inter‐spouse transmission occurred sexually, through blood–blood contact, or otherwise. Inter‐spouse transmission may have contributed to the high prevalence among elderly populations of Central Africa since some patients infected during healthcare subsequently transmitted the virus to their spouse. J. Med. Virol. 83:2113–2118, 2011. © 2011 Wiley Periodicals, Inc.
Number of mutations within CTL‐defined epitopes of the hepatitis B Virus (HBV) core region is associated with HBV disease progression
Authors: Kim Daniel , Lyoo Kwang Soo , Smith Davey , Hur Wonhee , Hong Sung Woo , Sung Pil Soo , Yoon Seung Kew , Mehta Sanjay
Published: October 2011

The virologic determinants of progressive liver disease associated with hepatitis B virus (HBV) remain unclear. Previous investigations have associated HBV disease with specific mutations but this association may be confounded by HBV genotype, HLA haplotype of the infected individual or both. The association between non‐synonymous mutations located within putative cytotoxic T‐lymphocyte directed epitopes (CDE) of the HBV core region and disease states was investigated. Subjects infected with HBV were enrolled from a clinical cohort in Seoul, Korea, and HBV core gene sequences were analyzed for mutational patterns inside and outside of CDE with respect to subject demographics and HBV‐related disease states. No specific mutation or pattern of mutations were associated with progressive disease states; however, individuals with cirrhosis and hepatocellular carcinoma had greater numbers of non‐synonymous mutations within CDE when compared to those with chronic HBV infection who were HBeAg positive (P = 0.007 and 0.026, respectively). In conclusion, this study demonstrates that HBV disease progression is associated with viral escape mutations that are a marker of CTL activity. These data suggest that the number of non‐synonymous mutations in the HBV core region may predict HBV disease progression better than any single mutation or pattern of mutations. J. Med. Virol. 83:2082–2087, 2011. © 2011 Wiley Periodicals, Inc.
Prospective evaluation of epidemiological, clinical, and microbiological features of pandemic influenza A (H1N1) virus infection in Italy
Authors: Fabbiani Massimiliano , Sali Michela , Di Cristo Valentina , Pignataro Giulia , Prete Valentina , Farina Salvatore , D'Avino Alessandro , Manzara Stefania , dal Verme Lorenzo Zileri , Silveri Nicolò Gentiloni , Cauda Roberto , Delogu Giovanni , Fadda Giovanni , Di Giambenedetto Simona
Published: October 2011

Since several characteristics of pandemic influenza A (H1N1) virus infection remain to be determined, this study aimed to describe clinical features and complications of patients infected with H1N1. Subjects affected by influenza‐like illnesses and a control group of asymptomatic patients were enrolled prospectively at an Emergency Department from October 2009 to April 2010. At enrollment, clinical data and nasopharyngeal swabs for virological analyses were obtained. Ill subjects were followed until recovery and swabs were collected weekly in patients infected with H1N1. Of 318 patients enrolled, 92 (28.9%) were positive to H1N1. Patients infected with H1N1 were mainly young adults and complained classic influenza‐like symptoms. Fever was observed for a median time of 5 (IQR 3–7) days. Hospitalization occurred in 27.7% with 2% requiring intensive care unit admission: median length of hospitalization was 6 days (IQR 5–9). Pneumonia was diagnosed in 19.6% of patients. A similar proportion of lower airways involvement and of clinical complications was observed in subjects testing positive or negative for H1N1. However, patients infected with H1N1 were younger and hospitalized for a shorter period as compared to the control group (P = 0.002 and P = 0.045, respectively). Older age, asthma/chronic obstructive pulmonary disease and hypertension were associated with an increased risk of pneumonia. Viral shedding was observed for at least 1 week in 21.3% of patients. Asymptomatic infection was uncommon (1.1%). Respiratory syndromes caused by H1N1 and factors associated with disease severity were investigated and compared to influenza‐like illnesses of other origin. Such findings might contribute to improve clinical and epidemiological management of the disease. J. Med. Virol. 83:2057–2065, 2011. © 2011 Wiley Periodicals, Inc.
Near‐full genome characterization of unclassified hepatitis c virus strains relating to genotypes 1 and 4
Authors: Demetriou Victoria L. , Kostrikis Leondios G.
Published: October 2011

Near‐full genome sequences are presented in this report for the first time of unclassified HCV strains amplified using RT‐PCR from plasma of patients living in Cyprus. One strain appears to be a unique genotype‐1‐like isolate, displaying closer phylogenetic relationship to genotype 1 strains than other genotypes. Two isolates representing an unclassified variant of genotype 4 were also amplified, cases of which have been found elsewhere in the world in patients of central African origin and could now be assigned provisionally as new subtype 4v. The near‐full genome nucleotide sequences of unclassified HCV isolates provide reference sequences of variants unknown previously, and contribute to the publicly available HCV sequence data to be used for diagnosis or research. J. Med. Virol. 83:2119–2127, 2011. © 2011 Wiley Periodicals, Inc.
Epstein–Barr virus gene expression and latent membrane protein 1 gene polymorphism in pediatric liver transplant recipients
Authors: Kasztelewicz Beata , Jankowska Irena , Pawłowska Joanna , Teisseyre Joanna , Dzierżanowska‐Fangrat Katarzyna
Published: October 2011

Immunosuppressed pediatric transplant recipients are at risk of developing Epstein–Barr virus (EBV)‐associated complications (such as post‐transplant lymphoproliferative disorders). Monitoring of the EBV DNA level in blood alone has a low predictive value for the post‐transplant course of EBV infection and its complications. Therefore, additional prognostic markers are widely sought. The study aim was to analyze EBV gene expression patterns and LMP1 polymorphism in relation to EBV DNA levels in pediatric liver transplant recipients. EBV load measurement, LMP1 variant, and gene expression analysis were performed in collected prospectively multiple blood samples from 30 patients. Several distinct patterns of EBV gene expression were identified: latency 2 (71%), latency 3 (13%), latency 0 (11%), and lytic infection (5%). In most children's multiple blood samples, both EBV gene expression patterns and expression levels of individual EBV genes varied significantly over time. EBV gene expression patterns were not associated with the EBV load. However, the viral load correlated with the LMP1 and LMP2 expression (r = 0.34; P = 0.006, and r = 0.45; P = 0.001, respectively). Two variants of the LMP1 gene were detected, and they were consistent over time in individual patients. A wild type of LMP1 was associated with higher EBV‐DNA loads (P = 0.03). This indicates that EBV infection in immunosuppressed patients is a very dynamic process, but changes in the state of EBV infection do not influence significantly the viral load. The latter, however, can be associated with the activity of LMP1 and LMP2 genes, as well as polymorphism of LMP1. J. Med. Virol. 83:2182–2190, 2011. © 2011 Wiley Periodicals, Inc.
Functional interaction between the dorsal hippocampus and the striatum in visual discrimination learning
Authors: Fidalgo C. , Conejo N.M. , González‐Pardo H. , Arias J.L.
Published: October 2011

The hippocampus and the striatum have traditionally been considered as part of different and independent memory systems. However, there is evidence that supports a functional interaction between the hippocampus and the dorsal striatum at least in particular learning tasks. Here, we evaluated the functional contribution of both brain regions in a visual discrimination learning task using cytochrome c oxidase (CO) quantitative histochemistry. Compared with other brain metabolic mapping techniques, CO activity reflects steady‐state neuronal energy demand. Rats were trained for 6 days in a water T‐maze to find a hidden escape platform associated with an intramaze visual cue. A control group of animals swam for an equivalent amount of time compared as the trained group but without any escape platform available. After finishing the behavioral task, CO activity was measured in subdivisions of the dorsal hippocampus and the dorsal striatum in both groups. Results show significantly higher CO activity in the CA1 area and the dentate gyrus of the dorsal hippocampus in the trained rats compared with the control group. In addition, a significant negative functional cross‐correlation between area CA1 of the dorsal hippocampus and the anterodorsal striatum was found. Our results support current theories on competitive interaction of different memory systems during visual discrimination learning. © 2011 Wiley Periodicals, Inc.
Liquid chromatography incorporating ultraviolet and electrochemical analyses for dual detection of zeranol and zearalenone metabolites in mouldy grains
Authors: Hsieh Han‐Yun , Shyu Ching‐Lin , Liao Chen‐Wei , Lee Ren‐Jye , Lee Maw‐Rong , Vickroy Thomas W , Chou Chi‐Chung
Published: October 2011

BACKGROUND: Zeranol (Z) is a semi‐synthetic mycotoxin that is used in some countries as a growth‐promoting agent in livestock. In view of the known oestrogenic actions by Z and certain Z analogues, significant concerns exist with regard to the presence of Z residues in human foods and the potential for untoward effects, including carcinogenicity within the reproductive system. In order to confirm that foods are free from harmful Z residues, regulators need a quick and reliable analytical method that can be used for routine confirmation of Z‐positive samples identified by enzyme‐linked immunosorbent assay (ELISA) screening. In this study the authors have developed and validated a simple and rapid high‐performance liquid chromatography method incorporating ultraviolet (UV) absorbance (wavelength 274 nm) and electrochemical (EC) dual‐mode detection for simultaneous determination of Z‐related mycotoxins produced from mouldy grain matrices, including rice, soybean and corn flakes.

RESULTS: Recoveries for all analytes were around 80% and the limits of detection ranged from 10 to 25 ng mL−1 for UV and from 50 to 90 ng mL−1 for EC detection with good accuracy and reproducibility. Differential profiles and occurrence rates of Z, β‐zearalenol, β‐zearalanol and α‐zearalenol in naturally moulded grain matrices were observed, indicating different metabolite patterns and possibly grain‐specific effects of mycotoxin exposure for humans and animals. The strength of this dual detection method lies in its selectivity characterised by a carbon screen‐printed electrode such that aflatoxin interference is precluded.

CONCLUSION: The combined dual detection technique affords quick and reliable semi‐confirmative and quantitative information on multiple types of Z analogues in mouldy grains without the necessity of using expensive mass spectrometry. The method is considered a superior supplement to ELISA, which only screens total Z immunoreactivity. Copyright © 2011 Society of Chemical Industry
Is sarcosine a biomarker for prostate cancer?
Authors: Issaq Haleem J. , Veenstra Timothy D.
Published: October 2011

Sarcosine was suggested in a letter to Nature in 2009 as a biomarker for prostate cancer. This communication reviews what has been accomplished to date to determine whether sarcosine is or is not a biomarker for prostate cancer that can replace prostate‐specific antigen tests.
Hydrolytic Degradation Behavior of Poly(rac‐lactide)‐block‐poly(propylene glycol)‐block‐poly(rac‐lactide) Dimethacrylate Derived Networks Designed for Biomedical Applications
Authors: Wischke Christian , Tripodo Giuseppe , Choi Nok‐Young , Lendlein Andreas
Published: October 2011

For polymer‐based degradable implants, mechanical performance and degradation behavior need to be precisely controlled. Based on a rational design, this work comprehensively describes the properties of photo‐crosslinked polymer networks prepared from poly(rac‐lactide)‐block‐poly(propylene glycol)‐block‐poly(rac‐lactide) dimethacrylate precursors during degradation. By varying the length of poly(rac‐lactide) blocks connected to a central 4 kDa polyether block, microphase separated networks with adjustable crosslinking density, hydrophilicity/hydrophobicity ratio, thermal, and mechanical properties are obtained. The materials are characterized by a low water uptake, controlled mass loss, and slowly decreasing wet‐state E moduli in the kPa range.

magnified image
Stability conditions under change of base field
Authors: Sosna Pawel
Published: October 2011

We investigate the behaviour of Bridgeland stability conditions under change of base field with particular focus on the case of finite Galois extensions. In particular, we prove that for a variety X over a field K and a finite Galois extension L/K the stability manifold of X embeds as a closed submanifold into the stability manifold of the base change variety.
Strategic Interaction between Governments and Investors under Privatization Programs
Authors: El‐Shazly Alaa
Published: October 2011

This article analyses the strategic moves of governments and investors under privatization programs in a game‐theoretic context. In sequential‐move games of both perfect information and incomplete information, the best response of the strategic investors to observing a slow pace of privatization is to have a low participation in economic activity because of concerns over public policy credibility. This is true even if the government chooses to randomize its action to send mixed signals to the investors while adopting a slow pace of privatization for budgetary reasons. However, the outcome is Pareto inferior to a situation of phased but fast implementation of privatization programs and high private‐sector participation under plausible assumptions. Copyright © 2011 John Wiley & Sons, Ltd.
Influence of poly(N‐isopropylacrylamide) and poly(N,N′‐diethyl acrylamide) coatings on polysulfone/polyacrylonitrile‐based membranes for protein separation
Authors: Barroso Telma , Viveiros Raquel , Coelho Margarida , Casimiro Teresa , Botelho do Rego Ana M. , Aguiar‐Ricardo Ana
Published: October 2011

Herein we describe the design and the assembly of temperature sensitive polysulfone (PS)/polyacrylonitrile (PAN) blend membranes using supercritical fluid technology. Blended membranes were prepared using the CO2‐assisted phase inversion method, and their pores were coated with two thermoresponsive hydrogels‐poly(N‐isopropylacrylamide) (PNIPAAm) and poly(N,N′‐diethylacrylamide) (PDEAAm). Permeation experiments of bovine serum albumin (BSA) and lysozyme (LYS) solutions were used to evaluate the performance and temperature‐responsive behavior of coated membranes. While membranes coated with PNIPAAm presented similar protein permeation profiles at temperatures below and above its lower critical solution temperature, PDEAAm coating imparted a temperature‐responsive behavior to PS/PAN (90:10) membranes and selective permeation of proteins with different sizes. Copyright © 2011 John Wiley & Sons, Ltd.
Towards high‐performance biopackaging: barrier and mechanical properties of dual‐action polycaprolactone/zinc oxide nanocomposites
Authors: Elen K. , Murariu M. , Peeters R. , Dubois Ph. , Mullens J. , Hardy A. , Van Bael M. K.
Published: October 2011

The properties of nanocomposites of biodegradable polycaprolactone containing zinc oxide (ZnO) nanoparticles with diverse morphologies, that is, ZnO nanospheres, nanorods, and nanodisks are investigated. It is demonstrated for the first time that the dual action of the ZnO nanoparticles reduces the gas permeability of the nanocomposites via two mechanisms: first by the creation of a tortuous path and second by gas adsorption. Depending on the morphology of the particles, the oxygen permeability can be reduced by more than 60%. Tensile tests show that the nanocomposites remain very ductile. The nominal strain for all nanocomposites is higher than 500% before fracture occurs. The Young's modulus and tensile strength of the nanocomposites increase at higher ZnO concentrations. This behavior is more pronounced in the case of ZnO nanorods. As a result, the incorporation of ZnO nanoparticles into (bio)polymers provides an opportunity to manufacture polymer‐based nanocomposite materials, resulting in the production of high‐performance (bio)packaging. Copyright © 2011 John Wiley & Sons, Ltd.
Optimisation of Infrared‐assisted Extraction of Rutin from Crude Flos Sophorae Immaturus Using Response Surface Methodology and HPLC Analysis
Authors: Li Fa‐jie , Ning Su‐li , Li Yan , Yu Ying‐jia , Shen Ci‐dan , Duan Geng‐li
Published: October 2011

Introduction

Rutin, one of main constituents in Flos Sophorae Immaturus, has been proven to possess several pharmacological properties such as anti‐oxidant, anti‐platelet, anti‐inflammatory effects and so on. However, optimisation of the extraction of rutin from Flos Sophorae Immaturus has rarely been reported. Thus, it is important to develop an effective method to obtain maximum yields of rutin from Flos Sophorae Immaturus.

Objective

To develop an infrared‐assisted extraction method for maximum rutin yield from crude Flos Sophorae Immaturus using response surface methodology and HPLC analysis.

Methodology

Through single factor experiments, ranges of the main variables (including methanol concentration, liquid:solid ratio, extraction time and infrared power) affecting the extraction yield of rutin were confirmed. A Box–Behnken design consisting of 24 experimental runs and five replicates at zero point was then applied and a regression model was obtained to predict the optimal extraction yield.

Results

The ANOVA analysis indicated that the regression equation fits very well with the actual situation. The optimal conditions were as follows: infrared power 204.90 W, liquid:solid ratio 30.00 mL/g, methanol concentration 70.00% and extraction time 4.80 min. Under optimal conditions the predicted maximum yield (125.70 mg rutin/0.5 g raw material) was consistent with the experimental value (126.32 ± 0.67 mg rutin/0.5 g raw material) (n = 3).

Conclusion

The application of response surface methodology was reliable and feasible in the optimisation of infrared‐assisted extraction of rutin from crude Flos Sophorae Immaturus. Copyright © 2011 John Wiley & Sons, Ltd.
Effects of Auxins on the Production of Steroidal Alkaloids in Rapidly Proliferating Tissue and Cell Cultures of Solanum lyratum
Authors: Kuo Chung‐Io , Chao Chi‐Hsein , Lu Mei‐Kuang
Published: October 2011

Introduction

Solanum lyratum, a rare species, is used to treat cancer, tumours and warts. Plant cell and tissue culture of S. lyratum, producing steroidal alkaloids, could be useful supplements to natural sources.

Objective

To study the production of solanine, solanidine and solasodine by adding auxin‐type phytohormones including indole‐3‐acetic acid (IAA), indole‐3‐butyric acid (IBA), naphthaleneacetic acid (NAA) and 2,4‐dichlorophenoxyacetic acid (2,4‐D) to cell and callus cultures of S. lyratum.

Methodology

Methanolic extracts were made from callus and cell cultures of S. lyratumand and analysed using RP C18 HPLC with UV detection.

Results

2,4‐D‐induced calli from roots led to a significant enhancement in solanine production with a value of 4.13 mg/g dry weight (DW). The maximal solanidine and solasodine levels of 6.26 and 7.69 mg/g DW were respectively obtained with IBA‐ and IAA‐treated S. lyratum cells at concentrations of 1 and 5 mg/L.

Conclusion

Auxins were found to be useful phytohormones for the production of steroidal alkaloids. The callus and cell culture system developed is simple and can hence be a method of production of steroidal alkaloids in S. lyratum and other Solanaceae species. Copyright © 2011 John Wiley & Sons, Ltd.
Preparation and properties of epoxy nanocomposites. Part 2: The effect of dispersion and intercalation/exfoliation of organoclay on mechanical properties
Authors: Ngo T.‐D. , Ton‐That M.‐T. , Hoa S.V. , Cole K.C.
Published: October 2011

The effect of the dispersion and intercalation/exfoliation of organoclay on the mechanical properties of epoxy nanocomposites was studied. The epoxy resin was EPON828 and the hardener was Jeffamine D‐230. The organoclay Cloisite 30B was used. Nanocomposites were prepared by different mixing devices that can generate different shear forces, such as a mechanical stirrer, a microfluidizer, and a homogenizer. The results indicate that the modulus increases almost linearly with the clay loading and also is improved with the quality of microdispersion, although the latter plays a less important role. On the other hand, only good dispersion can improve the strength, while poor dispersion results in loss of strength. The strength levels off above 4 wt% organoclay loading. It can be concluded that finer and more uniform dispersion increases the clay surface area available for interaction with the matrix and reduces stress concentration in the large aggregates that initiate the failure under stress. It is also observed that the presence of C30B does not significantly affect the glass transition (Tg) of the epoxy systems regardless of the level of clay dispersion and clay loading. Dynamic mechanic analysis (DMA) shows the positive effect of dispersion and intercalation/exfoliation on the storage modulus of epoxy nanocomposites (ENCs). POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers
Study of the effects of multi‐walled carbon nanotubes on mechanical performance and thermal stability of polypropylene
Authors: Pascual J. , Peris F. , Boronat T. , Fenollar O. , Balart R.
Published: October 2011

Carbon nanotubes (CNTs) have been added to polypropylene (PP) matrix to improve the overall performance of composites. The mixing process has been carried out by melt compounding using a twin screw co‐rotating extruder with different CNTs amounts in the 0.5–10 wt% from a concentrated PP‐CNTs masterbatch (20 wt% CNTs). Results show a remarkable increase in tensile strength and elastic modulus while a decrease in elongation at break is detected. With regard to thermal behavior, a remarkable increase in thermal stability at high temperatures (decomposition process studied by thermogravimetric analysis) is obtained as the CNTs amount increases. In addition to this improvement, a noticeable increase in thermal stability at medium temperatures (degradation onset determined by differential scanning calorimetry, DSC) is also observed. In a similar way, other property related to thermal and mechanical performance, such as Vicat softening temperature (VST) is improved with CNTs content. The optimum balance between cost and properties seems to be in the 1–3 wt% range. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers