bluuebunny/crossref_metadata_2025 huggingface dataset:
Systems Biology: The synergistic interplay between biology and mathematics
Authors: Dhurjati Prasad , Mahadevan Radhakrishnan
Published: March 2008

Systems Biology is a nascent field that arose from the technology driven omics measurement revolution. It goes beyond mere data analysis and focuses on the biological behaviour emerging from the dynamic interactions between system components that are organized in a hierarchical and highly connected manner. Mathematical models have been used as a conceptual framework to study such systems and their impact is maximal when there is a synergistic interplay of the models with experimental data and biological domain knowledge. The review provides an introduction to the modelling process and selectively highlights manuscripts that have strong biological impact.
Effect of molecular weight and charge density on the performance of polyacrylamide in low‐grade oil sand ore processing
Authors: Li Haihong , Long Jun , Xu Zhenghe , Masliyah Jacob H.
Published: March 2008

The effect of charge density and molecular weight (MW) of partially hydrolyzed polyacrylamide (HPAM) polymers on their performance in processing low‐grade oil sand ores was investigated. Bitumen extraction and tailings settling tests were carried out and an atomic force microscope (AFM) was used to directly measure the bitumen‐solid and solid‐solid interaction forces. It was found that HPAM polymers with a low MW acted as dispersants in the bitumen extraction process, resulting in low bitumen recovery and slow tailings settling but improved froth quality. In contrast, the use of HPAM polymers with a high MW improved both bitumen recovery and tailings settling but deteriorated froth quality. To achieve high bitumen recovery and fast tailings settling, a HPAM polymer must have a low to medium charge density (∼30%) and a high MW (17.5 million Daltons). A stronger clay‐bitumen adhesion force normally resulted in a lower bitumen recovery. Fast tailings settling was achieved in the presence of a strong solid‐solid adhesion force.
Novel polymer aids for low‐grade oil sand ore processing
Authors: Li Haihong , Long Jun , Xu Zhenghe , Masliyah Jacob H.
Published: March 2008

In the present study, a hybrid Al(OH)3‐polyacrylamide (Al‐PAM) was synthesized and used in combination with a partially hydrolyzed polyacrylamide (HPAM) to process a low‐grade oil sand ore. It was found that Al‐PAM was capable to improve bitumen froth quality and tailings settling. But it led to deterioration in bitumen recovery due to the formation of large bitumen lumps during the bitumen extraction process. To resolve this problem, HPAM was added in combination with Al‐PAM as a dual system. The use of the dual system at a low dosage achieved a holistic improvement in bitumen recovery, froth quality, and tailings settling. To understand the role of Al‐PAM and the dual system in the bitumen extraction process, bitumen‐clay, bitumen‐bitumen, and clay‐sand interaction and adhesion forces were directly measured using an atomic force microscope (AFM). The measured forces indicate that bitumen recovery and tailings settling are controlled by the colloidal interaction and adhesion forces between the oil sand components.
Modelling crystal growth between potash particles near contact points during drying processes. Part II: Analysis, results, and comparison with experimental data
Authors: Wang Yan , Evitts Richard W. , Besant Robert W.
Published: March 2008

Caking of bulk granular materials is a serious problem that affects many industries including the mineral processing industry. Caking occurs when bulk materials undergo wetting and drying cycles and it has been thought that it occurs due to the formation of new crystal bridges between individual particles. In the first paper in this series a mathematical model is developed for the crystal formation process that occurs at the contact point between two particles. In Part II, numerical simulations of the model are used to determine the effects of changes for several independent parameters in this model: initial moisture content; rate of evaporation of the salt solution from the particle surface; relative size of the contact region compared to the initial film thickness of salt solution; and supersaturation levels near the contact point. Non‐dimensional graphical curves of these simulations are used to compare the effects of each parameter for the deposition of salt crystals near the contact point. These results, when compared to data for cake strength in potash specimens which were obtained for various initial moisture contents, drying rate, and chemical composition of the particle surfaces, show good qualitative agreement even though cake strength and mass recrystallization near a contact point are different physical phenomena. The numerical results show that the mass of crystal deposition near the contact point will increase with increased initial moisture content and decreased evaporation rate. It is also found that variations in the degree of supersaturation near the contact point causes significant variations in the crystal mass deposition near the contact point.
Application of MRI phase‐difference mapping to assessment of vascular concentrations of BMS agent in mice
Authors: Ribot Emeline Julie , Thiaudière Eric , Roulland Richard , Brugières Pierre , Rahmouni Alain , Voisin Pierre , Franconi Jean‐Michel , Miraux Sylvain
Published: March 2008

Direct quantitation of contrast agent concentration can be performed using dynamic susceptibility contrast MRI. This method is based on phase imaging and administration of paramagnetic agents such as gadolinium‐chelates. This technique has only been applied on humans or primates. However, numerous research models have been developed on small animals like mice. For this reason, the aim of this work was the application of this MRI technique, allowing the direct quantitation of the contrast agent concentrations in vivo, in the mouse vascular system at high field. For this purpose, Dy–DOTA has been preferred to Gd–DOTA due to a lower T2* effect. Dy‐DOTA shifts in Larmor frequency were measured by phase difference mapping, using fast gradient‐echo imaging at short echo times. Such an acquisition sequence allowed the limitation of susceptibility artifacts at high magnetic fields and phase wrapping. As demonstrated in a phantom oriented parallel to the static magnetic field, it is possible to measure contrast agent concentrations between 0 and 10 mm with an uncertainty of about 100 µm. Finally, the method was applied on living mice at 4.7 T. After the bolus injection, the evolution of contrast agent concentrations was assessed in brain blood vessels parallel to B0. Long‐term disappearance of contrast agent was monitored at high spatial resolution every 15 s. Alternatively, lower resolved images at 0.72 s time‐resolution allowed preliminary assessment of arterial input functions. The feasibility of quantitative bolus‐tracking in small rodents opens the way for comprehensive descriptions of flow and over time‐dependent biological processes, especially in pathological murine models. Copyright © 2008 John Wiley & Sons, Ltd.
Role of endogenous sleep‐wake and analgesic systems in anesthesia
Authors: Lu Jun , Nelson Laura E. , Franks Nick , Maze Mervyn , Chamberlin Nancy L. , Saper Clifford B.
Published: March 2008

Classical anesthetics of the γ‐aminobutyric acid type A receptor (GABAA)‐enhancing class (e.g., pentobarbital, chloral hydrate, muscimol, and ethanol) produce analgesia and unconsciousness (sedation). Dissociative anesthetics that antagonize the N‐methyl‐D‐aspartate (NMDA) receptor (e.g., ketamine, MK‐801, dextromethorphan, and phencyclidine) produce analgesia but do not induce complete loss of consciousness. To understand the mechanisms underlying loss of consciousness and analgesia induced by general anesthetics, we examined the patterns of expression of c‐Fos protein in the brain and correlated these with physiological effects of systemically administering GABAergic agents and ketamine at dosages used clinically for anesthesia in rats. We found that GABAergic agents produced predominantly delta activity in the electroencephalogram (EEG) and sedation. In contrast, anesthetic doses of ketamine induced sedation, followed by active arousal behaviors, and produced a faster EEG in the theta range. Consistent with its behavioral effects, ketamine induced Fos expression in cholinergic, monoaminergic, and orexinergic arousal systems and completely suppressed Fos immunoreactivity in the sleep‐promoting ventrolateral preoptic nucleus (VLPO). In contrast, GABAergic agents suppressed Fos in the same arousal‐promoting systems but increased the number of Fos‐immunoreactive neurons in the VLPO compared with waking control animals. All anesthetics tested induced Fos in the spinally projecting noradrenergic A5–7 groups. 6‐hydroxydopamine lesions of the A5–7 groups or ibotenic acid lesions of the ventrolateral periaqueductal gray matter (vlPAG) attenuated antinociceptive responses to noxious thermal stimulation (tail‐flick test) by both types of anesthetics. We hypothesize that neural substrates of sleep‐wake behavior are engaged by low‐dose sedative anesthetics and that the mesopontine descending noradrenergic cell groups contribute to the analgesic effects of both NMDA receptor antagonists and GABAA receptor‐enhancing anesthetics. J. Comp. Neurol. 508:648–662, 2008. © 2008 Wiley‐Liss, Inc.
Point and extended defects in superconductors
Authors: Obaidat I. M. , Goeckner H. P. , Albiss B. A. , Kouvel J. S.
Published: March 2008

The effect of point defects created by γ‐irradiation and extended defects created by Pb‐ion irradiation on the behavior of the critical current density, Jc in several superconductors have been investigated. We have found a limitation of the role of both types of defects on enhancing Jc. We report an explanation of the effect of γ‐irradiation and Pb‐ion irradiation doses on Jc in these materials. The explanation is based on combining several competing mechanisms of irradiation which we believe to take place mainly in the regions of the grain boundaries. The influences of these mechanisms were found to vary with the irradiation dose level. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and luminescence properties of large‐scale zinc oxide nanotetrapods
Authors: Panda S. K. , Singh N. , Hooda J. , Jacob C.
Published: March 2008

Large‐scale zinc oxide (ZnO) nanotetrapods have been grown on p‐type Si (111) substrate by oxidizing zinc pieces in air by thermal evaporation technique without the presence of any catalyst. The size and morphology of the nanostructures was found to depend on experimental parameters. The grown nanostructures were characterized by X‐ray Diffraction (XRD), Photoluminescence (PL), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), High Resolution TEM (HRTEM) and analysis of elemental composition was done by Energy Dispersive X‐ray analysis (EDX). The EDX spectrum shows that the grown product contains Zn and O only. The X‐ray diffraction pattern indicates that the microstructure of the obtained products is typical hexagonal wurtzite ZnO. The optical properties were studied using room temperature PL spectroscopy which indicates that the products are of high optical quality and the near band edge UV transition peak intensity increases with decrease in tetrapod size. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystallization features of YBa2Cu3O7‐δ in the Y2BaCuO5‐BaCuO2‐CuO and Y2Cu2O5‐BaCuO2 systems
Authors: Kalanda N. A. , Gurskii L. I. , Saad A. M. , Truhan V. M. , Haliakevich T. V.
Published: March 2008

Based on the data of X‐ray phase and microstructure analysis, the sample composition was optimized in order to provide maximum size of the textured macrograins of YBa2Cu3O7‐δ and of the crystallites in the Y2BaCuO5‐BaCuO2‐CuO, Y2Cu2O5‐BaCuO2 systems. The growth rate has been studied and the YBa2Cu3O7‐δ growth activation energy has been calculated for the samples of Y2BaCuO5+3BaCuO2+2.3CuO, Y2BaCuO5+3BaCuO2+0.6CuO, and Y2Cu2O5+3.5BaCuO2 compounds in the temperature range of 1240‐1270K for the case of use of the Y2Cu2O5 and Y2BaCuO5 precursors with an average grain diameter of 10 μm and 1mm. A crystallization mechanism of YBa2Cu3O7‐δ in the Y2BaCuO5‐BaCuO2‐CuO and Y2Cu2O5‐BaCuO2 systems in the case of different sizes of Y2BaCuO5 and Y2Cu2O5 precursor grains was proposed and validated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Low temperature EPR spectra of Fe3+ centers in ternary layered TlGaS2 crystal
Authors: Acikgoz M. , Kazan S. , Mikailov F. A. , Kerimova E. , Aktas B.
Published: March 2008

The results of low temperature electron paramagnetic resonance (EPR) study of Fe doped TlGaS2 single crystal in the temperature range of 5‐300 K are presented. Iron was added to the growth mixture in amounts corresponding to a molar ratio Fe/Ga of about 1%. The EPR signal due to Fe3+ centers located at the centers of GaS4 tetrahedrons has been observed. A transformation of EPR spectra has been observed on decreasing the temperature, which is attributed to lowering of the number of resonance lines. The simulation of rotational patterns of the resonance fields exhibits a decrease of the number of centers at low temperatures as a contrary to those of isostructural compounds of TlGaS2. On comparing the EPR spectra of Fe3+ centers in TlGaSe2, it has been revealed that the Tl atoms lose their zigzag alignment observed previously at room temperature and rearranged to equal structural positions on Tl chains on lowering the temperature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Gold nanoparticles induce protein crystallization
Authors: Hodzhaoglu F. , Kurniawan F. , Mirsky V. , Nanev C.
Published: March 2008

Nucleation of protein crystals by gold nanoparticles was observed. Lysozyme and ferritin were used as model proteins. The effect was established with uncoated gold nanoparticles and with gold nanoparticles coated by 16‐mercaptodecanoic acid. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
CFD‐based optimization of aerofoils using radial basis functions for domain element parameterization and mesh deformation
Authors: Morris A. M. , Allen C. B. , Rendall T. C. S.
Published: March 2008

A novel domain element shape parameterization method is presented for computational fluid dynamics‐based shape optimization. The method is to achieve two aims: (1) provide a generic ‘wrap‐around’ optimization tool that is independent of both flow solver and grid generation package and (2) provide a method that allows high‐fidelity aerodynamic optimization of two‐ and three‐dimensional bodies with a low number of design variables. The parameterization technique uses radial basis functions to transfer domain element movements into deformations of the design surface and corresponding aerodynamic mesh, thus allowing total independence from the grid generation package (structured or unstructured). Independence from the flow solver (either inviscid, viscous, aeroelastic) is achieved by obtaining sensitivity information for an advanced gradient‐based optimizer (feasible sequential quadratic programming) by finite‐differences.

Results are presented for two‐dimensional aerofoil inverse design and drag optimization problems. Inverse design results demonstrate that a large proportion of the design space is feasible with a relatively low number of design variables using the domain element parameterization. Heavily constrained (in lift, volume, and moment) two‐dimensional aerofoil drag optimization has shown that significant improvements over existing designs can be achieved using this method, through the use of various objective functions. Copyright © 2008 John Wiley & Sons, Ltd.
Regulation of prostaglandin E2 synthase expression in activated primary rat microglia: Evidence for uncoupled regulation of mPGES‐1 and COX‐2
Authors: de Oliveira Antonio Carlos Pinheiro , Candelario‐Jalil Eduardo , Bhatia Harsharan S. , Lieb Klaus , Hüll Michael , Fiebich Bernd L.
Published: March 2008

Prostaglandin E2 (PGE2) is among the most important mediators involved in neuroinflammatory processes. The final step of its synthesis is regulated by enzymes termed prostaglandin E2 synthases (PGES). Three PGES are known, cytosolic (c)PGES, membrane‐associated (m)PGES‐1 and mPGES‐2. The expression of mPGES‐1 is induced by inflammatory stimuli such as lipopolysaccharide (LPS), interleukin (IL)‐1β, and tumor necrosis factor (TNF)‐α. Although some roles of mPGES‐1 have already been suggested, its function in the CNS and the signaling pathways involved in its upregulation are poorly understood. In this study, we examined the regulation of mPGES‐1 in primary rat microglia and the signaling pathways involved in its expression. Whereas the expression of cPGES and mPGES‐2 was not stimulated by LPS, low doses of LPS (0.1–1 ng/mL) sufficiently stimulated mPGES‐1 mRNA expression. A corresponding protein synthesis, however, was obtained only with higher doses (10–100 ng/mL). The LPS‐induced increase of mPGES‐1 was inhibited by different signaling pathway inhibitors, such as SP600125, LY294002, GF109203X, and SC‐514, suggesting the involvement of c‐Jun N‐terminal kinase (JNK), phosphatidylinositol 3‐kinase (PI‐3K)/Akt, protein kinase C (PKC) pathways, and the nuclear factor (NF)‐κB, respectively. In contrast to other reports, LPS‐induced mPGES‐1 synthesis was not invariably coupled to the synthesis of COX‐2, since inhibition of PI‐3K with LY294002 decreased mPGES‐1 but increased COX‐2 levels. This detailed view of the intracellular signaling pathways involved in mPGES‐1 expression in activated microglia opens a new avenue in the search for novel potential therapeutic targets to reduce neuroinflammation, and demonstrates that mPGES‐1 expression is not strictly coupled to the expression of COX‐2. © 2008 Wiley‐Liss, Inc.
HIV‐1‐infected and/or immune‐activated macrophage‐secreted TNF‐α affects human fetal cortical neural progenitor cell proliferation and differentiation
Authors: Peng Hui , Whitney Nicholas , Wu Yumei , Tian Changhai , Dou Huanyu , Zhou You , Zheng Jialin
Published: March 2008

Neurogenesis, tied to the proliferation, migration and differentiation of neural progenitor cells (NPC) is affected during neurodegenerative diseases, but how neurogenesis is affected during HIV‐1 associated dementia (HAD) has not been fully addressed. Here we test the hypothesis that HIV‐1‐infected and/or immune‐activated brain macrophages affect NPC proliferation and differentiation through the regulation of cytokines. We showed that human monocyte‐derived macrophages (MDM) conditioned medium (MCM) induces a dose dependant increase in NPC proliferation. Conditioned media from lipopolysaccharide (LPS)‐activated MDM (LPS‐MCM) or HIV‐infected MCM (HIV‐MCM) induced a profound increase in NPC proliferation. HIV‐infected and LPS‐activated MCM (HIV+LPS‐MCM) induced the most robust increase in NPC proliferation. Moreover, LPS‐MCM and HIV+LPS‐MCM decreased β‐III‐tubulin and increased GFAP expression, demonstrating an induction of gliogenesis and inhibition of neurogenesis. The increase of NPC proliferation and gliogenesis correlated with increases in production of TNF‐α by infected/activated MDM. Although both IL‐1β and TNF‐α induced NPC proliferation and gliogenesis, these effects were only partially abrogated by soluble TNF‐α receptors R1 and R2 (TNF‐R1R2), but not by the IL‐1 receptor antagonist (IL‐1ra). This indicated that the HIV‐1‐infected/LPS‐activated MCM‐mediated effects were, in part, through TNF‐α. These observations were confirmed in severe combined immunodeficient (SCID) mice with HIV‐1 encephalitis (HIVE). In these HIVE mice, NPC injected with HIV‐infected MDM showed more astrocyte differentiation and less neuronal differentiation compared to NPC injection alone. These observations demonstrated that HIV‐1‐infected and immune‐activated MDM could affect neurogenesis through induction of NPC proliferation, inhibition of neurogenesis, and activation of gliogenesis. © 2008 Wiley‐Liss, Inc.
Replication of Theiler's virus requires NF‐κB‐activation: Higher viral replication and spreading in astrocytes from susceptible mice
Authors: Kang Min Hyung , So Eui Young , Park Hyesuk , Kim Byung S.
Published: March 2008

To investigate viral replication and cell–cell spreading in astrocytes, recombinant Theiler's murine encephalomyelitis virus (TMEV) expressing green fluorescent protein (GFP) during the replication was generated. GFP and TMEV proteins were processed correctly in infected cells and production of viral proteins could be tracked by fluorescent microscopy. Viral replication of both wild‐type TMEV and GFP‐TMEV was dependent on the activation of NF‐κB and partially MAP kinase, based on chemical inhibition studies. Viral replication was significantly reduced in primary astrocytes from NF‐κB1 (p105)‐deficient mice compared with that from wild‐type control mice, whereas cytokine production was enhanced. These results suggest an association of canonical NF‐κB subunits in viral replication, but not cytokine production. Viral replication was also suppressed in both IKKα and IKKβ‐deficient mouse embryonic fibroblasts (MEFs), compared with that in wild‐type MEF. However, the inhibition was significantly greater in IKKβ‐deficient MEF, suggesting that IKKβ plays a stronger role in supporting viral replication. Interestingly, viral replication and spreading in primary astrocytes from susceptible SJL/J mice were several‐fold higher than those in astrocytes from resistant C57BL/6 mice, suggesting that higher viral replication levels in astrocytes may also contribute to the viral persistence in the central nervous system (CNS) of susceptible SJL/J mice. A relatively higher level of activated NF‐κB was found in the nuclei of virus‐infected SJL astrocytes compared with C57BL/6 astrocytes suggest that the NF‐κB activation level affects on viral replication. © 2008 Wiley‐Liss, Inc.
Modulation of astrocytic metabolic phenotype by proinflammatory cytokines
Authors: Gavillet Mathilde , Allaman Igor , Magistretti Pierre J.
Published: March 2008

Astrocytes play an important role in nervous system homeostasis. In particular, they contribute to the regulation of local energy metabolism and to oxidative stress defence. In previous experiments, we showed that long‐term treatment with interleukin 1α (IL‐1α) or tumor necrosis factor‐α (TNFα) alone increases glucose utilization in primary culture of mouse astrocytes. In our study, we report that a combination of IL‐1β and TNFα exerts a synergistic effect on glucose utilization and markedly modifies the metabolic phenotype of astrocytes. Thus, IL‐1β+TNFα treated astrocytes show a marked decrease in glycogen levels, a slight but not significant decrease in lactate release as well as a massive increase in both the pentose phosphate pathway and TCA cycle activities. Glutamate‐stimulated glucose utilization and lactate release, a typical feature of astrocyte energy metabolism, are altered after pretreatment with IL‐1β+TNFα. As far as mechanisms for oxidative stress defence are concerned, we observed that treatment with IL‐1β+TNFα decreases cellular glutathione content and increases glutathione release into the extracellular space while stimulating superoxide anion and nitric oxide production as well as H2O2 release. Interestingly, stimulation of glucose utilization by IL‐1β+TNFα is not affected by the antioxidant N‐acetyl‐L‐cysteine, suggesting that cellular stress does not account for this effect. Finally, the effects of cytokines on glucose utilization appear to involve multiple signaling cascades including the phosphoinositide 3‐kinase and mitogen‐activated protein kinases. Taken together these results establish that a proinflammatory environment such as observed in several neuropathological conditions including Alzheimer's disease, markedly modifies the metabolic phenotype of astrocytes. © 2008 Wiley‐Liss, Inc.
Ceramic membrane pretreatment of monosodium glutamate isoelectric supernatant to facilitate (NH4)2SO4 recovery by electrodialysis
Authors: Ren Hongyan , Sun Fubao , Shi Shaoyuan , Cong Wei
Published: March 2008

BACKGROUND: The large output of monosodium glutamate in China has produced huge amounts of isoelectric supernatant containing 40–60 g L−1 (NH4)2SO4. With the increasing national emphasis on environmental protection and recycling, it is necessary to find a cost‐effective and environment‐friendly alternative to recover the (NH4)2SO4. This paper reports on investigations of the electrodialysis process for (NH4)2SO4 recovery from isoelectric supernatant pretreated by ceramic membrane.

RESULTS: For ceramic membrane pretreatment, the optimal pore size chosen was 0.2 µm. After a 250 min run, permeate flux was still maintained at 90 L m−2 h−1 (v = 2.8 m s−1, ΔTMP = 0.12 MPa, concentration factor = 7). Meanwhile, the total solids and proteins content in condensed supernatant were high, up to 78 g L−1 and 24 g L−1, respectively, which greatly favors future cell protein harvest. With the chosen current density of 17 mA cm−2, the energy consumption and time for six consecutive batches for electrodialysis were 2.6–2.7 kW h kg−1 sulfate and ∼100 min, based on ∼80% ammonium sulfate recovery from pretreated isoelectric supernatant.

CONCLUSION: Ceramic membrane pretreatment was shown to be a promising pretreatment strategy, applicable to the electrodialysis process to recover ammonium sulfate from isoelectric supernatant produced during monosodium glutamate production. Copyright © 2008 Society of Chemical Industry
Aerobic degradation by white‐rot fungi of trichloroethylene (TCE) and mixtures of TCE and perchloroethylene (PCE)
Authors: Marco‐Urrea Ernest , Gabarrell Xavier , Caminal Gloria , Vicent Teresa , Adinarayana Reddy C
Published: March 2008

BACKGROUND: Trichloroethylene (TCE) and perchloroethylene (PCE) are considered among the most important groundwater pollutants around the world. These compounds are usually found together in polluted environments but little is known about the ability of microorganisms to simultaneously degrade TCE and PCE.

RESULTS: Data showed that several species of white‐rot fungi, including Trametes versicolor, Ganoderma lucidum, and Irpex lacteus, degrade substantial levels of TCE in pure culture. T. versicolor was chosen for further study since it degraded higher levels of TCE than the other organisms. Initial glucose concentration and reoxygenation of samples increased the amount of TCE dechlorination, but no significant difference in percentage TCE degradation was observed. T. versicolor was able to degrade 34.1 and 47.7% of PCE and TCE added as mixtures (containing 5 and 10 mg L−1, respectively).

CONCLUSIONS: The degradation ability of TCE was extended to other species of white‐rot fungi. Percentage degradation as well as chloride release from mixtures of TCE and PCE showed that T. versicolor degrades mixtures of TCE and PCE almost as well as its ability to degrade individually added TCE or PCE. The results suggest the potential promise of T. versicolor for bioremediation of TCE and PCE in the environment. Copyright © 2008 Society of Chemical Industry
Engineering physiologically controlled pacemaker cells with lentiviral HCN4 gene transfer
Authors: Boink Gerard J. J. , Verkerk Arie O. , van Amersfoorth Shirley C. M. , Tasseron Sara J. , van der Rijt Roos , Bakker Diane , Linnenbank André C. , van der Meulen Jan , de Bakker Jacques M. T. , Seppen Jurgen , Tan Hanno L.
Published: March 2008

Background

Research on biological pacemakers for the heart has so far mainly focused on short‐term gene and cell therapies. To develop a clinically relevant biological pacemaker, long‐term function and incorporation of autonomic modulation are crucial. Lentiviral vectors can mediate long‐term gene expression, while isoform 4 of the Hyperpolarization‐activated Cyclic Nucleotide‐gated channel (encoded by HCN4) contributes to pacemaker function and responds maximally to cAMP, the second messenger in autonomic modulation.

Material and Methods

Action potential (AP) properties and pacemaker current (If) were studied in single neonatal rat ventricular myocytes that overexpressed HCN4 after lentiviral gene transduction. Autonomic responsiveness and cycle length stability were studied using extracellular electrograms of confluent cultured monolayers.

Results

Perforated patch‐clamp experiments demonstrated that HCN4‐transduced single cardiac myocytes exhibited a 10‐fold higher If than non‐transduced single myocytes, along with slow diastolic depolarization, comparable to pacemaker cells of the sinoatrial node, the dominant native pacemaker. HCN4‐transduced monolayers exhibited a 47% increase in beating rate, compared to controls. Upon addition of DBcAMP, HCN4‐transduced monolayers had beating rates which were 54% faster than baseline and significantly more regular than controls.

Conclusions

Lentiviral vectors efficiently transduce cardiac myocytes and mediate functional gene expression. Because HCN4‐transduced myocytes demonstrate an increase in spontaneous beating rate and responsiveness to autonomic modulation, this approach may be useful to create a biological pacemaker. Copyright © 2008 John Wiley & Sons, Ltd.
How spatially coherent and statistically robust are temporal changes in extreme precipitation in the contiguous USA?
Authors: Pryor S. C. , Howe J. A. , Kunkel K. E.
Published: March 2008

Century‐long precipitation records from stations in the contiguous USA indicate an increased frequency of rainy days over the past century and some evolution in the probability distributions of precipitation amount. Temporal trends in eight metrics of the precipitation climate are of similar magnitude and sign regardless of whether they are derived from bootstrapping of regression residuals or using the Kendall's tau statistic, though the bootstrap technique generally resolved a larger number of ‘significant’ trends. There is substantial variability in terms of the magnitude, significance and sign of the linear trends with specific metrics, and they are sensitive to recording bias of light precipitation events in the early part of the 20th century. The majority of stations that exhibit significant linear trends show evidence of increases in the intensity of events above the 95th percentile. The resolved trends tend to have a larger magnitude at the end of the century. Spatial variability as manifest in the spatial autocorrelation in the interannual variability and trends in extreme metrics is manifest at a range of scales, but in general the correlation between stations is significant only for separation of distances of a few tens of kilometres. The largest trends towards increased annual total precipitation, number of rainy days and intense precipitation (e.g. fraction of precipitation derived from events in excess of the 90th percentile value) are focussed on the Central Plains/northwestern Midwest. Copyright © 2008 Royal Meteorological Society
FT‐Raman, IR and UV‐visible spectral investigations and ab initio computations of a nonlinear food dye amaranth
Authors: Snehalatha M. , Ravikumar C. , Sekar N. , Jayakumar V. S. , Joe I. Hubert
Published: March 2008

Amaranth (E123, Food Red 9, FD & C Red 2) is a sulfonated azo dye used as a color additive in foodstuffs, pharmaceuticals and cosmetics. FT‐IR and FT‐Raman spectra of amaranth were recorded and analyzed. Density functional theory (DFT) calculations were performed to derive the equilibrium geometry, vibrational wavenumbers, intensities and first hyperpolarizability. The results of the optimized molecular structure gave clear evidence for the intramolecular charge transfer (ICT) and intramolecular hydrogen bonding in the molecule. Azo stretching wavenumbers are lowered owing to conjugation and π‐electron delocalization. Time‐dependent density functional theory (TD‐DFT) calculations of the electronic spectra were performed on the optimized structure and compared with the experimental UV‐visible spectrum. Vibrational spectra, natural bonding orbitals (NBO) analysis and optimized geometry indicate CH·N hydrogen bonding in the molecule. The first hyperpolarizability of the molecule was calculated. The optical nonlinearity of the dye is due to the donation of the electron density from the hydroxyl group of the conjugated system via naphthalene (2) ring into π*‐orbital of the azo moiety. Copyright © 2008 John Wiley & Sons, Ltd.
Can iron and zinc in rice grains (Oryza sativa L.) be biofortified with nitrogen fertilisation under pot conditions?
Authors: Zhang Jin , Wu Lianghuan , Wang Minyan
Published: March 2008

BACKGROUND: Because only grain yield has been investigated, the influence of fertilisation by N on the concentration of Fe and Zn in polished rice has been overlooked in China. So, using the rice cultivars of the indica Zhenong 952 and the japonica Bing 98110, pot experiments were conducted to investigate the amounts of N fertiliser (applied as urea at rates of 0, 0.50, 1.00 and 1.50 g N pot−1) that would lead to the optimum Fe and Zn concentrations in polished rice as well as grain yield.

RESULTS: For Zhenong 952, the optimal Fe and Zn concentration as well as grain yield was attained at a N application of 1.00 g pot−1; for Bing 98110 the optimum N was 1.50 g pot−1. The ratio of Zn deposited in brown rice was about 40% of the total Zn in the plant irrespective of N application. However, Fe was only about 3%. Fe concentration in brown rice was approximately one‐half of the rice husk, one‐fifth of the peduncles, and one‐tenth of the leaves, and a little more than 1% of the root.

CONCLUSION: The optimum N application, alone, on rice crops could increase Fe concentration in polished rice, but had an adverse effect for Zn. Fe appeared not to be as easily accumulated into rice seeds as was Zn. Copyright © 2008 Society of Chemical Industry
The application of macroalga Pithophora varia Wille enriched with microelements by biosorption as biological feed supplement for livestock
Authors: Michalak Izabela , Chojnacka Katarzyna
Published: March 2008

BACKGROUND: The paper discusses biosorption of microelements by a freshwater macroalga Pithophora varia Wille to produce biological feed supplement for livestock. The biomass was enriched with microelements recommended by feeding standards in a single and a multi‐metal system.

RESULTS: The equilibrium of biosorption was described by using a Langmuir model and the following values of the maximum biosorption capacity in the single‐metal system were obtained: Zn(II), 61.1 mg g−1; Co(II), 52.3 mg g−1; Cu(II), 55.7 mg g−1; and Mn(II), 38.3 mg g−1. The average value of maximum biosorption capacity expressed in molar units for all the cations was equal 1.7 ± 0.2 meq g−1, suggesting chemical rather than physical biosorption. It was also found that the mechanism of biosorption was due to cation exchange of alkali and alkaline earth metals with microelements. The biomass was also enriched with microelements in multi‐metal system. The total metal ion binding capacity in the multi‐metal system was two‐fold lower than in the single‐metal system and was 0.90 meq g−1 in the preparation for laying hens and 0.95 meq g−1 in the supplement for swine.

CONCLUSION: Finally, the level of supplementation of livestock feed (with enriched single‐ and multi‐metal system macroalga), to cover 25% of total requirements for microelements, according to feeding standards, was provided. Copyright © 2008 Society of Chemical Industry
Rice protein concentrate partially replaces dried whey in the diet for early‐weaned piglets and improves their growth performance
Authors: Hou Zhen‐Ping , Yin Yu‐Long , Huang Rui‐Lin , Li Tie‐Jun , Hou Rongqing , Liu Yulan , Wu Xin , Liu Zhiqiang , Wang Wence , Xiong Hua , Wu Guo‐yao , Tan Liang‐xi
Published: March 2008

BACKGROUND: Recently, rice protein concentrate (RPC), a much cheaper source of dietary protein, has become commercially available for use in the feed industry. Importantly, dietary supplementation with RPC can increase feed intake by early‐weaned pigs. The objective of this study was to determine whether RPC can replace milk protein in the diet for early‐weaned pigs.

RESULTS: Neither average daily gain (ADG), average daily feed intake (ADFI), nor the feed/gain ratio differed among the treatment groups in weeks 1 and 2. In week 3, the addition of 5 or 10% RPC to diets increased (P < 0.05) ADFI and ADG of pigs compared to those in the control group fed a 60% dried whey diet. During the entire 21‐day trial, ADFI and ADG were greater (P < 0.05) in pigs fed the 5 and 10% RCP diets than in pigs fed the 60% dried whey and 15% RCP diets. There were no differences in the serum concentrations of growth hormone on days 14 and 21, serum concentrations of insulin growth factor‐I (IGF‐I) on day 14, or IGF‐I gene expression in liver and skeletal muscle on days 14 and 21 among the dietary treatments. Serum concentrations of IGF‐I in pigs fed the 5, 10 and 15% RPC diets were greater than those in pigs fed the 60% dried whey diet.

CONCLUSION: Findings indicate that up to 10% RPC can be used to replace dried whey in the diet for 7‐ to 21‐day‐old weaned piglets and can improve their growth performance. Copyright © 2008 Society of Chemical Industry
Use of durum residue flour, a lower value product of durum milling, by incorporation into wheat flour dough without deterioration in baking quality
Authors: Sissons Mike J , Batey Ian L , Balfe Sue , Hare Ray , MacRitchie Finlay
Published: March 2008

BACKGROUND: During the milling of durum wheat to semolina, about 10–15% of total products produced is residue flour, a lower value product than the semolina. This study investigated the potential for using the durum residue flour as an additive in bread‐making to improve its potential commercial value.

RESULTS: Incorporation of residue durum flour from 102 breeding lines into a low protein flour and standard bakers' flour at 20% incorporation improved the bake loaf volume with minimal change in Mixograph dough mixing time and peak resistance in many of the lines tested. Loaf yellow b was always increased even with only a 10% incorporation. Baking flours can tolerate 20% incorporation with no deleterious affects on loaf volume and bake score.

CONCLUSION: The results show a potential for using the lower value durum residue flour for baking bread of acceptable quality with a slightly higher yellow colour. This would improve the profitability for the miller and provide alternative ingredients to the baker for preparing specialty breads. Copyright © 2008 Crown in the Right of the State of New South Wales and Society of Chemical Industry
Polycyclic aromatic hydrocarbons in smoked cheese
Authors: Suchanová Marie , Hajšlová Jana , Tomaniová Monika , Kocourek Vladimír , Babička Luboš
Published: March 2008

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) represent a group of organic compounds containing two or more aromatic rings. Their control in the human food chain is required due to the mutagenic and carcinogenic potential, exhibited in vertebrates. In the present study, the occurrence of PAHs in 36 cheeses smoked by various processes was investigated.

RESULTS: PAH concentrations (sum of 15 US EPA PAHs) found in samples smoked under controlled industrial conditions were at level 0.11 µg kg−1, whereas in ‘home‐made’ cheeses, the PAH content was up to 10 times higher. A similar trend was observed for B[a]P, a marker compound representing carcinogenic PAHs. While its levels in commercial products prepared by controlled smoking technologies were close to the limit of quantification (0.03 µg kg−1); in household samples, the B[a]P content ranged from 0.6 to 0.9 µg kg−1. Significantly higher amounts of PAHs (up to three to six times) were found in surface layers as compared to internal parts of cheese.

CONCLUSION: Although smoked cheese is a popular food, only several papers have focused on PAH levels in these products. This paper evaluates the contribution of different smoking technologies to PAH contamination of several cheeses and thus can help in a risk assessment associated with their consumption. Moreover, the study shows the concentration ratios of selected PAHs, from which the type of smoking technology can be indicated. The results obtained in this study also supported the suggestion of the EU Scientific Committee on Food to use benzo[a]pyrene as an indicator of the occurrence of higher‐molecular mass PAHs. Copyright © 2008 Society of Chemical Industry
Effects of dietary humate supplementation to broilers on performance, slaughter, carcass and meat colour
Authors: Esenbuğa Nurinisa , Macit Muhlis , Karaoglu Mevlut , Aksu Muhammet Irfan , Bilgin Omer Cevdet
Published: March 2008

BACKGROUND: This experiment was designed to examine the effect of dietary humate supplementation primarily on pH and colour parameters of carcasses, breast fillets and drumsticks and, secondarily on performance and carcass characteristics in broilers.

RESULTS: A total of 240 male broiler chicks (Ross‐308) were randomly allocated to four dietary treatments varying in supplemental humate level (0, 0.1, 0.2 and 0.3% for H0, H1, H2 and H3). Dietary humate supplementation did not affect performance traits and slaughter, hot carcass weights and yields. Carcass‐related variables (pH, L*, a*, b*, H* and C*) were responsive to the dietary treatments. The L*, a*, b*, and C* values for drumstick muscles were higher than those for breast muscles. Except for the L* value, meat colour parameters changed due to packaging. The a* value was higher and b* value was lower for vacuum packaged breast and drumsticks than for those aerobic packaged. Storage period affected colour parameters; while L*, b*, H* and C* values were higher for drumstick skin than for drumstick meat; the a* value was greater in drumstick meat than in skin.

CONCLUSION: pH and colour parameters of carcasses, breast fillets and drumsticks of broilers were improved by dietary humate supplementation. However, responses of broiler performance and slaughter and carcass characteristics were minimal. Copyright © 2008 Society of Chemical Industry
Interaction between nitric oxide and hydrogen peroxide in postharvest tomato resistance response to Rhizopus nigricans
Authors: Fan Bei , Shen Lin , Liu Kailang , Zhao Danying , Yu Mengmeng , Sheng Jiping
Published: March 2008

BACKGROUND: Nitric oxide (NO) and hydrogen peroxide (H2O2) are signal molecules involved in the disease response of plants, and there is a close relationship between them. To investigate the interaction of NO and H2O2 during disease resistance response in postharvest fruits and vegetables, tomato (Lycopersicon esculentum cv. Lichun) fruits were treated after harvest by vacuum infiltration with NO donor and H2O2 scavenger.

RESULTS: The resistance of tomato fruits to Rhizopus nigricans Ehrenb. invasion and the activities of defensive enzymes phenylalanine ammonia‐lyase, chitinase and glutathione S‐transferase were enhanced by NO. However, these effects of NO on resistance were weakened by H2O2 scavenger, which showed that H2O2 was required in NO‐mediated disease resistance in harvested tomato. Meanwhile, the endogenous H2O2 level was dual‐regulated by NO. During the earlier period of storage the H2O2 peak was advanced by NO, but during the later period of storage, when the concentration of H2O2 was relatively higher, H2O2 accumulation was delayed by NO. The activities of superoxide dismutase, ascorbate peroxidase and catalase were involved in this regulation.

CONCLUSION: The results imply that application of exogenous NO can enhance the disease resistance of postharvest tomato; NO may interact with H2O2 and exert its effect by modulating the endogenous H2O2 level. This result is useful for the further investigation and application of NO in postharvest disease control. Copyright © 2008 Society of Chemical Industry
Unsupervised classification methods in food sciences: discussion and outlook
Authors: Kozak Marcin , Scaman Christine H
Published: March 2008

This paper reviews three unsupervised multivariate classification methods: principal component analysis, principal component similarity analysis and heuristic cluster analysis. The theoretical basis of each method is presented in brief, and assumptions inherent to the methods are highlighted. A literature review shows that these methods have sometimes been used inappropriately or without referencing all essential parameters. The paper also brings to the attention of the reader a relatively unknown method: probabilistic or model‐based cluster analysis. The goal of this method is to uncover the true classification of objects rather than a convenient classification provided by the other methods. For this reason it is felt that model‐based cluster analysis will have broad application in the future. Copyright © 2008 Society of Chemical Industry
Suppression of postharvest blue mould of apple fruit by Cryptococcus laurentii and N6‐benzyladenine
Authors: Yu Ting , Wang Lianping , Yin Yun , Feng Fengqin , Zheng Xiaodong
Published: March 2008

BACKGROUND: Cryptococcus laurentii is a well‐known postharvest yeast antagonist. N6‐benzyladenine (6‐BA), a cytokinin plant hormone, has a role in retarding ripening and senescence of harvested produce. This study was conducted to evaluate the efficacy of C. laurentii and 6‐BA in reducing the blue mould disease of apple fruit.

RESULTS: The combination of C. laurentii with 6‐BA (20 µg mL−1) was more effective in suppressing the Penicillium expansum infection in apple fruit wounds than C. laurentii alone, although 6‐BA (20 µg mL−1) alone neither affected the growth of C. laurentii nor reduced the incidence of the blue mould disease in vivo. Moreover, treatment of apple fruit with C. laurentii and 6‐BA (20 µg mL−1) resulted in stimulation of superoxide dismutase activity but in inhibition of the increase in peroxidase activity.

CONCLUSION: 6‐BA (20 µg mL−1) could enhance the efficacy of C. laurentii in reducing the postharvest blue mould disease of apple fruit, which offered great potential in minimizing the postharvest decay of apple fruit in an integrated pest management strategy. Copyright © 2008 Society of Chemical Industry
Use of alginate or zein as edible coatings to delay postharvest ripening process and to maintain tomato (Solanum lycopersicon Mill) quality
Authors: Zapata Pedro Javier , Guillén Fabián , Martínez‐Romero Domingo , Castillo Salvador , Valero Daniel , Serrano María
Published: March 2008

BACKGROUND: Edible coatings could be effective tools for delaying the ripening process of fruits. Alginate or zein as edible coatings were assayed in tomato in order to maintain parameters related to quality during postharvest storage.

RESULTS: Coated tomatoes showed lower respiration rate and ethylene production than control ones, with a twofold lower concentration of ethylene precursor. In addition, the evolution of parameters related to tomato quality losses, such as softening, colour evolution and weight loss, was significantly delayed (4–6 days on average) in coated tomatoes as compared to controls. Thereafter, sugars, organic acids (and especially ascorbic acid) and scores from sensory analysis remained at much higher levels at the end of storage in treated than in control tomatoes.

CONCLUSIONS: Coatings based on alginate or zein could be effective tools for delaying the tomato‐ripening process during postharvest storage, and in turn maintaining tomato quality and its acceptability by consumers. Copyright © 2008 Society of Chemical Industry