bluuebunny/crossref_metadata_2025 huggingface dataset:
The Gas‐Phase Chemistry of cis‐Diammineplatinum(II) Complexes: A Joint Experimental and Theoretical Study
Authors: Springer Andreas , Bürgel Christian , Böhrsch Verena , Mitrić Roland , Bonačić‐Koutecký Vlasta , Linscheid Michael W.
Published: July 2006

Prior to reactions with DNA, the anticancer drug cisplatin [PtII(NH3)2Cl2] forms a series of solvolysis intermediates by successive replacement of the chloro ligands by water or hydroxyl groups. The bonding of water to PtII is weak, and it is easily substituted by donor ligands present in the solution, for example, amines or alcohols. We studied such compounds using high‐resolution electrospray mass spectrometry with a linear ion trap and DFT computations. This combination allows for the first time a detailed description of the reactions initiated by the central atom of the complexes. Positively charged cisplatin adducts with primary and secondary alcohols ([PtII(NH3)2(ROH)Cl]+) show unexpected reactions when fragmented in a linear ion trap. Either water loss is accompanied by formation of the corresponding carbene complex, or loss of the corresponding aldehyde/ketone leads to the formation of the complex [Pt(NH3)2(H2)Cl]+. Complete loss of the alcohol ligand is not observed for kinetic reasons. A detailed investigation by DFT and molecular dynamics for the cisplatin/methanol complex [PtII(NH3)2(CH3OH)Cl]+ allowed identification of the reaction mechanisms leading to the observed fragmentation patterns. The initial step for both fragmentation pathways is activation of the α‐CH bond and subsequent H transfer within the complex. Direct activation of the OH or CO bond is less favorable. Ligands bound to the PtII center such as the chloro ligand can directly catalyze the reaction by intermediate binding of H atoms. Upon collision activation, adducts without an α‐H atom such as [Pt(NH3)2{(CH3)3COH}Cl]+ show loss of water or the corresponding alkene.
Theoretical Study of N2O Reduction by CO in Fe‐BEA Zeolite
Authors: Fischer Gerd , Goursot Annick , Coq Bernard , Delahay Gérard , Pal Sourav
Published: July 2006

Quantum mechanical (QM) and QM/molecular mechanics (MM) studies of the full catalytic cycle of N2O reduction by CO in Fe‐BEA zeolite, that is, oxidation of BEA‐Fe by N2O and reduction of BEA‐Fe‐αO by CO, is presented. A large QM cluster, representing half of the channel of the BEA zeolite, is used. The contribution of the MM embedding to the calculated activation energies is found to be negligible. The minimum‐energy paths for N2O decomposition and reduction with CO are calculated using the nudged elastic band (NEB) method. Calculated and experimental activation energies are in good agreement. The two possible orientations for the gaseous molecules adsorbing on the Fe site that are found lead to different activation energies.
C‐peptide improves neuropathy in type 1 diabetic BB/Wor‐rats
Authors: Zhang Weixian , Kamiya Hideki , Ekberg Karin , Wahren John , Sima Anders A. F.
Published: July 2006

Background

The spontaneously diabetic BB/Wor‐rat is a close model of human type 1 diabetes and develops diabetic polyneuropathy (DPN) similar to that seen in type 1 patients. Here we examine the therapeutic effects of C‐peptide, delivered as continuous infusion or once daily subcutaneous injections on established DPN.

Methods

Diabetic rats were treated from four to seven months duration of diabetes with full continuous replacement dose of rat C‐peptide via (a) osmopumps (OS), (b) full replacement dose (HSC) or (c) one‐third of full replacement dose (LSC) by once daily injections.

Results

Diabetic rats treated with OS showed improvements in motor nerve conduction velocity (p < 0.001), sural nerve myelinated fibre number (p < 0.005), size (p < 0.05), axonal area (p < 0.001), regeneration (p < 0.001) and overall neuropathy score (p < 0.001). The progressive decline in sensory nerve conduction velocity was fully prevented. The frequencies of Wallerian degeneration were decreased (p < 0.005). HSC‐treated rats showed prevention of further progression of DPN (p < 0.001), whereas LSC‐treated rats showed a milder progression of DPN (p < 0.001) compared to untreated rats as assessed by neuropathy score.

Conclusion

We conclude that (1) C‐peptide is effective in the treatment of established DPN, (2) its effect is dose‐dependent and (3) replacement by continuous infusion is the most effective administration of C‐peptide. Copyright © 2006 John Wiley & Sons, Ltd.
(Cyclen– and cyclam–pyridine)copper Complexes: The Role of the Pyridine Moiety in CuII and CuI Stabilisation
Authors: El Ghachtouli Sanae , Cadiou Cyril , Déchamps‐Olivier Isabelle , Chuburu Françoise , Aplincourt Michel , Roisnel Thierry
Published: July 2006

The protonation constants of cyclen– and cyclam–pyridine [1‐(pyridin‐2‐ylmethyl)‐1,4,7,10‐tetraazacyclododecane (L1) and 1‐(pyridin‐2‐ylmethyl)‐1,4,8,11‐tetraazacyclotetradecane (L2), respectively] and the stability constants (log β110) of the corresponding copper complexes ([CuL1]2+ and [CuL2]2+) were determined by potentiometric titrations. The complexes were subsequently isolated and characterised by X‐ray diffraction, UV/Vis spectroscopy and electrochemical studies. The [CuL2]2+ complex adopts two distinct and stable geometries (trans I and III), which mainly differ by the macrocycle configuration. The trans III configurational isomer can be converted into the trans I one by electron transfer. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Inferring power‐relevant thoughts and feelings in others: a signal detection analysis
Authors: Mast Marianne Schmid , Hall Judith A. , Ickes William
Published: July 2006

Drawing inferences about other people's thoughts and feelings related to power issues (‘power‐relevant’ thoughts and feelings) can affect how hierarchies are formed. Perceivers who infer such thoughts and feelings can be biased (i.e., over‐ or underestimating the occurrence of power‐relevant thoughts and feelings). We investigated whether the perceiver's gender and the perceiver's preference for a high or low power position (‘power preference’) affects the perceiver's bias toward attributing power‐relevant thoughts and feelings to others. Participants were 80 female and 35 male students who indicated their power preference and then guessed whether videotaped target individuals had experienced power‐relevant thoughts and feelings or not. Using a signal detection approach, we found that men who preferred a high power position overestimated the occurrence of power‐relevant thoughts and feelings in others more than men who preferred a low power position. No such difference in overestimation bias was found for women. Copyright © 2006 John Wiley & Sons, Ltd.
The powerful want to, the powerless have to: perceived constraint moderates causal attributions
Authors: Overbeck Jennifer R. , Tiedens Larissa Z. , Brion Sebastien
Published: July 2006

It is popularly believed that powerful people enjoy a nearly‐absolute lack of constraints, and that powerless people suffer under overwhelming constraints; in fact, such differences largely define the social categories of ‘powerful person’ and ‘powerless person.’ This association of power‐related social categories and constraint constitutes a stereotype that may lead perceivers to overlook other, more diagnostic information when explaining others' behavior. As a result, the actions of powerholders may tend to be seen as dispositionally motivated and those of the powerless as situationally motivated. This should occur because of both real differences in constraint, and bias in the failure to account for other, more diagnostic information about constraint. Two studies support these predictions. In Study 1, participants judged powerless workers as more situationally motivated, especially under coercion, than both controls and powerholders, who were judged as more dispositional. In Study 2, given more fine‐grained information about constraints and power, participants' attributions reflected both accurate use of this information and bias. Copyright © 2006 John Wiley & Sons, Ltd.
Effects of power on emotion and expression during a controversial group discussion
Authors: Berdahl Jennifer L. , Martorana Paul
Published: July 2006

The approach/inhibition theory of power proposes that elevated social power increases the experience and expression of positive emotions and that reduced social power increases the experience and expression of negative emotions (Keltner, Gruenfeld, & Anderson, 2003). The evidence to date for these proposed relationships is correlational. Studies that have attempted to find a causal link between power and emotions have failed to do so. The current study manipulated social power in 61 three‐person groups that engaged in a meaningful discussion (explanations for poverty in the US) that produced disagreements and strong emotions. High power individuals experienced and expressed more positive emotions and less anger than low power individuals did. High power individuals were also more likely than low power individuals to openly express their opinions during the group discussion. Implications for theory and future research are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Social power
Authors: Brauer Markus , Bourhis Richard Y.
Published: July 2006

In the present article, we discuss and compare recent theoretical and empirical contributions to the growing body of research on social power. In the last decade, five different theories on power have been proposed. These theories can be distinguished according to whether they focus on intrapersonal, interpersonal, intergroup or ideological processes. Our analysis leads us to claim that future theoretical contributions would have much to gain by addressing the issue of social power on multiple levels of analysis. The recent empirical work on social power suggests that powerful individuals and members of powerful groups differ from powerless individuals and members of powerless groups with regard to (a) how they perceive and judge others, (b) how they are evaluated as targets, and (c) how they behave. Those who have power perceive others more stereotypically and judge them more negatively. They also tend to take action more frequently and generally behave in a more variable manner. This difference in objective variability is further reinforced by perceivers' tendency to exaggerate the variability of high power groups. The latter two effects contribute to the phenomenon that high power groups are less often the target of stereotypes than low power groups. Copyright © 2006 John Wiley & Sons, Ltd.
Solid‐State Microelectrodes for Flow‐Cell Analysis Based on Planar Back‐Side Contact Transducers
Authors: Mamińska Renata , Wróblewski Wojciech
Published: July 2006

This paper presents an overview of the studies carried out in the recent years in our laboratory, on the construction of different solid‐state microelectrodes for flow‐cell analysis. The microelectrodes were based on planar transducers made from a printed circuit board and manufactured as back‐side contact structures, which facilitate their mounting in a flow‐cell. Performances of the polymeric membrane ion‐selective: coated‐wire microelectrodes and microsensors with a polyHEMA layer containing internal electrolyte are compared. Conducting polymer – polypyrrole doped with ester of sulfosuccinic acid – was added to the PVC membranes to develop all‐solid‐state microelectrodes without internal electrolyte solution, exhibiting good potential stability in time. Finally, all‐solid‐state reference microelectrodes based on back‐side contact transducers are prepared and examined. These structures were applied as reference electrodes in flow‐cell measurements with potassium‐selective planar microelectrodes.
Approaches to Improving the Lower Detection Limit of Polymeric Membrane Ion‐Selective Electrodes
Authors: Szigeti Zsófia , Vigassy Tamás , Bakker Eric , Pretsch Ernö
Published: July 2006

More than ten different approaches for improving the lower detection limit of polymeric membrane ion‐selective electrodes have been suggested during the recent years. In this contribution, their principles are briefly summarized with a focus to their general practical applicability. The methods that are the most rugged and the easiest to implement in a routine laboratory will be highlighted.
Multisensor Systems for Separate Determination of Homologous Anionic and Non‐Ionic Surfactants
Authors: Mikhaleva Natalia Mikhailovna , Kulapina Elena Grigorevna
Published: July 2006

The electrode, transport, selective properties and cross sensitivity of surfactant sensors based on various electrode‐active substances speak for their applicability in multisensor analysis. Permeability and ion flows of surfactants for ion‐exchange membranes are estimated. Influence of the nature and concentration of electrode‐active substances and the contacting solutions, membrane thickness on quantitative characteristics membrane transport is shown. The electrode, transport, and selective properties of surfactant membranes based on alkylpyridinium alkylsulfates and tetraphenylborate salts of complex cations of barium‐polyethoxylate enable their usage in multisensor systems (electronic tongue). Arrays of solid‐contact potentiometric sensors with a high cross sensitivity for separate detection of anionic and non‐ionic surfactant homologues in multicomponent systems are designed. With the usage of multisensor surfactant systems and mathematical methods the ability of separate detection of homologous anionic and non‐ionic surfactants in multicomponent model mixtures, natural waters and technical drugs is shown.
Electrochemical DNA Biosensor for Testing Pentamidine and Its Analogues as Potential Chemotherapeutics
Authors: Szpakowska Iwona , Krassowska‐Swiebocka Barbara , Maciejewska Dorota , Kazmierczak Pawel , Jemielita Wirginia , Konrad Magdalena , Trykowska Joanna , Maj‐Zurawska Magdalena
Published: July 2006

Electrochemical DNA‐based biosensors are used as screening devices for a rapid evaluation of chemical compounds interacting with double helix of the nucleic acid. Pentamidine is one of minor groove binding chemotherapeutics clinically used as anti‐PCP agent. Therefore, we designed, synthesized and tested some pentamidine analogues with diethyl ether linker and 1,2‐diazine (pyridazine) or 1,3,5‐triazine derivatives with cyanophenoxy substituent, precursors of amidine groups to establish if they can be more efficacious DNA interacting compounds than the original pentamidine drug. The tested compounds were: 1,5‐bis(4‐amidinophenoxy)pentane isethionate‐pentamidine (1) used as template, 6‐chloro‐3‐(4‐cyanophenoxy)pyridazine (2), 4,6‐dichloro‐2‐(4‐cyanophenoxy)‐1,3,5‐triazine (3), 4‐amidinophenol dihydrate (4), 1,5‐bis(4‐amidinophenoxy)‐3‐oxapentane dihydrochloride‐γ‐oxapentamidine (5), 1,5‐bis(N‐cyclohexyl‐4‐amidinophenoxy)‐3‐oxapentane dihydrochloride (6). The results show that none of the tested analogues binds dsDNA more strongly than the original drug pentamidine (1). Compound 2 with pyridazine group interacts with the nucleic acid in a different way than the one with triazine (3) – the signals obtained using DNA‐based biosensor had opposite features. Close derivatives 5 and 6 of the main drug pentamidine (1) showed a weak influence on the double‐stranded nucleic acid which proves that even small changes in the structure of a molecule can strongly affect the character and properties of the above mentioned compounds in the presence of DNA. In this context atomic charge distribution in the studied molecules is also discussed.
Depression in late‐life: shifting the paradigm from treatment to prevention
Authors: Whyte Ellen M. , Rovner Barry
Published: July 2006

Late‐life depression is very common and is associated with high rates of morbidity and mortality. While the field of geriatric psychiatry is focused on depression treatment, prevention is an enticing option. Prevention of late‐life depression would decrease both emotional suffering and depression‐associated morbidity and mortality and may decrease dependence on non‐mental health professionals to detect depression and to initiate a treatment referral. This paper will review current thinking on prevention research with a particular focus on its application to late‐life depression. To illustrate these issues, we discuss recent and ongoing clinical trials of interventions to prevent depression in two populations of older persons: those with age‐related macular degeneration (AMD) and those with cerebrovascular disease. Copyright © 2006 John Wiley & Sons, Ltd.
The tetracycline: Mg2+ complex: A molecular mechanics force field
Authors: Aleksandrov Alexey , Simonson Thomas
Published: July 2006

Tetracycline (Tc) is an important antibiotic, which binds specifically to the ribosome and several proteins, in the form of a Tc–:Mg2+ complex. To model Tc:protein and Tc:RNA interactions, we have developed a molecular mechanics force field model of Tc, which is consistent with the CHARMM force field for proteins and nucleic acids. We used structures from the Cambridge Crystallographic Data Base to identify the main Tc conformations that are likely to be present in solution and in biomolecular complexes. A conformational search was also done, using the MM3 force field to perform simulated annealing of Tc. Several resulting, low‐energy structures were optimized with an ab initio model and used in developing the new Tc force field. Atomic charges and Lennard‐Jones parameters were derived from a supermolecule ab initio approach. We considered the ab initio energies and geometries of a probe water molecule interacting with Tc at 36 different positions. We considered both a neutral and a zwitterionic Tc form, with and without bound Mg2+. The final rms deviation between the ab initio and force field energies, averaged over all forms, was just 0.35 kcal/mol. The model also reproduces the ab initio geometry and flexibility of Tc. As further tests, we did simulations of a Tc crystal, of Tc:Mg2+ and Tc:Ca2+ complexes in aqueous solution, and of a solvated complex between Tc:Mg2+ and the Tet repressor protein (TetR). With slight, ad hoc adjustments, the model can reproduce the experimental, relative, Tc binding affinities of Mg2+ and Ca2+. It performs well for the structure and fluctuations of the Tc:Mg2+:TetR complex. The model should therefore be suitable to investigate the interactions of Tc with proteins and RNA. It provides a starting point to parameterize other compounds in the large Tc family. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 1517–1533, 2006
Origin of hyperactivity in the hamster dorsal cochlear nucleus following intense sound exposure
Authors: Zhang J.S. , Kaltenbach J.A. , Godfrey D.A. , Wang J.
Published: July 2006

This study sought to determine whether maintenance of noise‐induced dorsal cochlear nucleus (DCN) hyperactivity depends on descending projections. Twenty‐two hamsters were exposed under anesthesia to a 10‐kHz tone at 125–130 dB SPL for 4 hr, and another 21 unexposed animals served as controls. After approximately 4–6 weeks of recovery, surgical transections were made to isolate the DCN from its adjacent brainstem structures. Spontaneous multiunit activity was recorded from the DCN surface 30–40 min after the surgical manipulations. Spontaneous rates were derived from the recording sites of the DCN along its mediolateral axis for each animal, yielding average spontaneous rates for both control and exposed groups. Histology was performed to assess the degree of sectioning of descending fiber tract connections to the cochlear nucleus, via the acoustic striae route, subpeduncular route, trapezoid body route, and ventral route of the olivocochlear bundle connection. The results showed that complete or nearly complete transections of descending inputs did not affect significantly the magnitude of DCN hyperactivity. However, this manipulation triggered a lateral shift of the peak mean rate, suggesting that descending inputs may play a modulatory role on the profile of DCN hyperactivity. Indeed, exposed animals with transection of only the strial route of entry manifested a level of hyperactivity much higher than that observed in exposed animals in which no sections were performed. This enhancement of DCN hyperactivity was weakened by damage to the subpeduncular or trapezoid routes of input, suggesting that the dorsally located inputs may have an inhibitory effect on DCN hyperactivity. © 2006 Wiley‐Liss, Inc.
Gene expression for enzymes and transporters involved in regulating adenosine and inosine levels in rat forebrain neurons, astrocytes and C6 glioma cells
Authors: Parkinson Fiona E. , Ferguson Jennifer , Zamzow Christina R. , Xiong Wei
Published: July 2006

In brain, levels of adenosine increase up to 100‐fold during cerebral ischemia. Based on in vitro studies, both astrocytes and neurons contribute to this adenosine release. Neurons release adenosine per se whereas astrocytes release adenine nucleotides that are metabolized to adenosine extracellularly. In contrast, inosine is released from both cell types via a nucleoside transporter. C6 glioma cells, which are derived from astrocytes, release inosine but not adenosine. The present study investigated the relative expression of purine metabolizing enzymes and transporters in neurons, astrocytes and C6 glioma cells by real‐time PCR analysis. In agreement with the extracellular formation of adenosine and intracellular formation of inosine by astrocytes, the present study showed high expression of ecto 5′‐nucleotidase and AMP deaminase type 3 in astrocytes. The lack of adenosine release from C6 glioma cells was consistent with the absence of expression of the AMP‐preferring cytosolic 5′‐nucleotidase in these cells. The predominance of nitrobenzylthioinosine (NBMPR) insensitive equilibrative nucleoside transport (ENT2) in all three cell types was consistent with the greater activity of this isoform in comparison to NBMPR‐sensitive ENT1 in these rat cells. Thus, cell type differences in adenosine formation and release are primarily a function of differences in expression of purinergic enzymes and transporters. © 2006 Wiley‐Liss, Inc.
Overexpression of copper/zinc‐superoxide dismutase in transgenic mice markedly impairs regeneration and increases development of neuropathic pain after sciatic nerve injury
Authors: Kotulska Katarzyna , LePecheur Marie , Marcol Wiesław , Lewin‐Kowalik Joanna , Larysz‐Brysz Magdalena , Paly Evelyn , Matuszek Iwona , London Jacqueline
Published: July 2006

Despite the general capacity of peripheral nervous system to regenerate, peripheral nerve injury is often followed by incomplete recovery of function, sometimes with the burden of neuropathic pain. The mechanisms of both regeneration and nociception have not been clarified, but it is known that inflammatory reactions are involved. Cu/Zn‐superoxide dismutase (SOD1) is an important scavenger protein that acts against oxidative stress. It has been shown to play an important role in apoptosis and inflammation. The aim of this study was to examine the role of SOD1 overexpression in peripheral nerve regeneration and neuropathic pain‐related behavior in mice. Sciatic nerves of SOD1‐overexpressing and FVB/N wild type‐mice were transected and immediately resutured. Evaluation of motor and sensory function and autotomy was carried out during 4 weeks of followup. We found markedly worse sciatic function index outcome as well as more significant atrophy of denervated muscles in SOD1‐overexpressing animals compared with wild type. Autotomy was markedly worse in SOD1 transgenic mice than in wild‐type animals. Histological evaluation revealed that the intensity of regeneration features, including numbers of GAP‐43‐positive growth cones, Schwann cells, and macrophages in the distal stump of the transected nerve, was also decreased in transgenic mice. Neuroma formation at the injury site was significantly more prominent in this group. Taken together, our findings suggest that SOD1 overexpression is deleterious for nerve regeneration processes and aggravates neuropathic pain‐like state in mice. This can be at least partially ascribed to disturbed inflammatory reactions at the injury site. © 2006 Wiley‐Liss, Inc.
Molecular mechanisms of pain in the anterior cingulate cortex
Authors: Zhuo Min
Published: July 2006

It is well known that peripheral sensory stimuli, including pain, trigger a series of neuronal activities along the somatosensory pathways as well as the neuronal network in the high brain structures. These neuronal activities not only produce appropriate physiological responses but also induce long‐term plastic changes in some of the central synapses. It is believed that long‐term synaptic changes help the brain to process and store new information. Such learning is critical for animals and humans to gain new knowledge of changing enviornment, generate appropriate emotional responses, and avoid dangerous stimuli in the future. In the case of permanent injury, however, the brain fails to distinguish the difference between “useful” and painful stimuli. Long‐term synaptic changes work against the system and at least in part contribute to chronic pain. In this short article, the possible molecular mechanisms for long‐term plasticity within the anterior cingulate cortex (ACC) will be discussed and reviewed, and it is hypothesized that potentiation of excitatory responses within the ACC contributes to chronic pain and pain‐related mental disorders. © 2006 Wiley‐Liss, Inc.
Assessment of textile dye remediation using biotic and abiotic agents
Authors: El‐Rahim Wafaa M. Abd
Published: July 2006

The aim of the current work was to assess the removal of direct and reactive dyes using biotic and abiotic agents. Removal of dyes and their derivatives from aqueous solutions was investigated using sugarcane bagasse, sawdust, rice straw, charcoal and fungal biomass as dye removing agents. Seven fungal strains known to have high capacity in removing textile dyes were used. Results of this study indicated that Penicillium commune, P. freii, and P. allii removed 96, 64 and 65%, respectively, of direct violet dye after two hours of incubation. In addition, the use of rice straw was shown to be more efficient in dye removal, than was bagasse or sawdust. Rice straw was effective in removing 72% of direct violet dye within 24 hours. However, with reactive dyes, removal activity was reduced to 27%. Similar trends were recorded with the other tested biotic agents, fast removal of reactive dye was not found after 48 hours of contact time. Results of this study indicate that low‐cost, renewable, bioadsorption agents are relatively effective in removing textile dyes from solution. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of Staphylococcus aureus strains isolated from humans in Argentina
Authors: Reinoso Elina Beatriz , Ibañez Fernando , Raspanti Claudia , Odierno Liliana , Bogni Cristina Inés
Published: July 2006

Humans are a natural reservoir of Staphylococcus aureus and asymptomatic colonization is far more common than infection. The aim of this work was to characterize genotypically 68 S. aureus strains isolated from nasal swabs of healthy people and from human clinical infections. A total of fourteen (20%) strains were susceptible to all the antimicrobials tested. The strains isolated from nasal swabs showed the lowest percentages of resistance. Resistance to one or more than one antibiotics tested was detected in 83% and 70% of the S. aureus strains isolated from clinical infections and nasal swabs, respectively. All of the 68 S. aureus strains were subject to RAPD‐PCR analysis. Cluster A‐I grouped 42 (87%) clinical infection strains and cluster A‐II grouped 13 (65%) strains isolated from nasal swabs suggesting a genetic relationship among S. aureus strains. Cluster A‐II grouped 65% of the S. aureus strains associated with the anterior nares, suggesting that these strains may be adapted to this site. Furthermore, five RAPD profiles isolated from nasal swabs, belonged to clusters B to F, were similar to strains isolated from clinical infection, suggesting that they might have a high propensity to cause disease. The results of the present study allow a characterization of S. aureus strains isolated from humans and shows that some S. aureus genotypes from nasal swabs are similar to the genotypes obtained from clinical infections, suggesting that clinical isolates may be originated from human normal flora. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bacterial community changes in diesel‐oil‐contaminated soil microcosms biostimulated with Luria–Bertani medium or bioaugmented with a petroleum‐degrading bacterium, Pseudomonas aeruginosa strain WatG
Authors: Ueno Akio , Ito Yukiya , Yamamoto Yusuke , Yumoto Isao , Okuyama Hidetoshi
Published: July 2006

The microbial community structure of diesel‐oil‐contaminated soil microcosms biostimulated with Luria–Bertani medium (LB‐BS) or bioaugmented with a petroleum‐degrading bacterium, Pseudomonas aeruginosa strain WatG (WatG‐BA), was investigated by denaturing gradient gel electrophoresis (DGGE) and by monitoring diesel oil degradation. The degradation in WatG‐BA (64.0% ± 4.2%) was higher than that in LB‐BS (49.5% ± 12.0%) during the first two weeks. The microbial community in WatG‐BA, which was markedly dominated by strain WatG, was much simpler than that in LB‐BS, where hydrocarbon degraders occurred after a lag of 3–7 days after the addition of diesel oil. The clustering profiles of the DGGE banding patterns of the two soil microcosms were only 12% similar. This difference is probably due to antibacterial substances, such as rhamnolipids, secreted by strain WatG. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Northern Hemisphere freezing/thawing index variations over the twentieth century
Authors: Frauenfeld Oliver W. , Zhang Tingjun , Mccreight James L.
Published: July 2006

Changes in the ground thermal regime in high‐latitude cold regions have important consequences for surface and subsurface hydrology, the surface energy and moisture balance, carbon exchange, as well as ecosystem diversity and productivity. However, assessing these changes, particularly in light of significant atmospheric and terrestrial changes in recent decades, remains a challenge owing to data sparseness and discontinuous observations. The annual freezing and thawing index can be useful in evaluating permafrost and seasonally frozen ground distribution, has important engineering applications, and is a useful indicator of high‐latitude climate change. The freezing/thawing index is generally defined based on daily observations, which are not readily available for many high‐latitude locations. We thus employ monthly air temperatures, and provide an assessment of the validity of this approach. On the basis of a comprehensive relative error (RE) evaluation we find that our methodology introduces errors of less than 5% for most high‐latitude land areas, and works well in many midlatitude regions as well. We evaluate a suite of gridded monthly temperature datasets and select the University of East Anglia's Climatic Research Unit (CRU) temperature product, available for 1901–2002. We are thus able to provide a continuous long‐term 25 km × 25 km gridded Northern Hemisphere freezing/thawing index. Long‐term climatologies of the freezing/thawing index delineate the cold regions of the Northern Hemisphere, as well as areas of seasonally frozen ground and permafrost. Objective trend analysis indicates that in recent decades, no significant changes have occurred in Russian permafrost regions; however, seasonally frozen ground areas are experiencing significant warming trends. Over North America, Canadian and Alaskan permafrost regions are experiencing a decrease in freezing index during the cold season, while coastal areas and eastern Canada are seeing significant increase in warm season thawing index. Copyright © 2006 Royal Meteorological Society.
A new quantitative method: non‐destructive study by Raman spectroscopy of dyes fixed on wool fibres
Authors: Salpin Frédérique , Trivier Francis , Lecomte Sophie , Coupry Claude
Published: July 2006

Raman spectroscopy was employed for the quantitative analysis of mixtures of the three dyes used at the Manufacture Nationale des Gobelins (Paris, France), fixed on wool fibres. It is based on a laboratory‐written program that implements the decomposition of the combined Raman spectrum into the relative contributions of the spectra of each constituent.

To perfect the method, it was first applied to fibres dyed at the laboratory and then extended to the dyeing baths, before and after the dyeing process. Binary and ternary mixtures, in which the quantities were known, were used. The percentages obtained by applying the quantitative analysis of the Raman spectra were similar to those introduced. The method therefore allows quantification of the dyes and gives information about the dyeing process. Fibres recently dyed at the workshop of the Manufacture Nationale des Gobelins with unknown proportions were analysed using this method. The results obtained are in conformity with the observed colour of the dyed hanks of wool. Copyright © 2006 John Wiley & Sons, Ltd.
The microstructure and tannin content of banana fruit and their likely influence on juice extraction
Authors: Kyamuhangire William , Krekling Trygve , Reed Elisabeth , Pehrson Robert
Published: July 2006

Extraction of banana juice using the traditional physical method is limited to Mbidde banana cultivars. Most other banana cultivars (including Matooke cultivars) do not produce juice by this method. A study of the microstructure and tannin content of banana fruit (Mbidde and Matooke cultivars) was carried out in order to understand the underlying factors in the juice extraction process and develop a working hypothesis to explain the mechanism of juice separation. Microscopic examination of pulp sections of Mbidde bananas revealed that their microstructure contained many more intensely stained and larger laticifer cells than pulp tissues of Matooke cultivars. On ripening, the intensity of staining of laticifer cells in Mbidde fruit appeared to increase, while there was limited or no staining in fruit of Matooke cultivars. There was also higher tannin content in Mbidde than in Matooke bananas at both unripe and ripe stages. The high tannin concentration corresponding to the unique presence of high numbers of laticifer cells in fruit of Mbidde cultivars suggests that the ability of the bananas to release juice is linked to tannins. During juice extraction the physical working of the banana pulp ruptures the laticifer cells, resulting in the release of tannins that interact with celluloses, hemicelluloses, proteins and, most importantly, pectins to form insoluble complexes, thus facilitating juice release. Copyright © 2006 Society of Chemical Industry
Biocomposites: technology, environmental credentials and market forces
Authors: Fowler Paul A , Hughes J Mark , Elias Robert M
Published: July 2006

Biocomposites offer a significant non‐food market for crop‐derived fibres and resins. Considerable growth has been seen in the use of biocomposites in the automotive and decking markets over the past decade or so, but application in other sectors has hitherto been limited. Nevertheless, with suitable development, the potential exists for biocomposites to enter new markets and thus stimulate an increase in demand for non‐food crops. This paper reviews some of the technological challenges being faced in bringing these materials to a wider market together with potential solutions, as well as discussing market forces influencing their commercial uptake. Copyright © 2006 Society of Chemical Industry
Variation in the carotenoid composition of acerola and its processed products
Authors: Porcu Ornella Maria , Rodriguez‐Amaya Delia B
Published: July 2006

Acerola is now commercially produced and processed in Brazil. Known for its very high vitamin C content, this fruit is also a good source of β‐carotene. The present study was carried out to verify variation in the carotenoid composition along the food chain. Neoxanthin, violaxanthin, lutein, β‐cryptoxanthin, α‐carotene and β‐carotene were found in the acerola fruit. β‐Carotene predominated with mean concentrations of 12.4 and 38.1 µg g−1 in the ripe fruit, 8.8 and 30.1 µg g−1 in the peeled ripe fruit and 5.4 and 12.0 µg g−1 in the partially ripe fruit of an undefined variety taken from home gardens and the commercial cultivar Olivier, respectively. Aside from β‐carotene, β‐cryptoxanthin increased significantly in both garden and commercial fruits and violaxanthin in the latter fruits during ripening. Peeling reduced β‐carotene in both garden and commercial lots, violaxanthin decreased in the commercial fruits, and the other carotenoids remained virtually unchanged. Four brands of frozen pulp and three brands of processed juice had variable and markedly lower carotenoid levels than those of the fresh fruit, indicating that the processing should be improved. Copyright © 2006 Society of Chemical Industry
Extra‐virgin and refined olive oils decrease plasma triglyceride, moderately affect lipoprotein oxidation susceptibility and increase bone density in growing pigs
Authors: Ostrowska Ewa , Gabler Nicholas K , Ridley Dan , Suster Danny , Eagling David R , Dunshea Frank R
Published: July 2006

The objective of this study was to determine the health benefits of extra‐virgin and refined olive oils, which are high in mono‐unsaturated fatty acids (MUFAs) and polyphenolic compounds using the pig as a model. Thirty‐two cross‐bred pigs were individually penned, allocated to one of four dietary treatments and fedad libitumfor 28 days. Two of the experimental diets consisted of a basal diet containing 12% tallow and either 7% sunflower oil (TSO) or 7% extra‐virgin olive oil (TEVO) on a w/w basis. The remaining diets contained 19% extra‐virgin olive oil (EVO) or 19% of refined olive oil (RO). On days 7, 14 and 28 fasted and 3‐h post‐prandial blood samples were taken. Body composition was measured at the beginning and end of the study using dual energy X‐ray absorptiometry. Daily gain, feed intake and lean and fat deposition were not significantly different between the treatments. However, the daily increase in bone mineral density was higher in pigs fed diets containing olive oil (1.23 vs 2.54, 6.28, 5.20 mg cm−2per day for TSO, TEVO, EVO and RO, respectively,P= 0.050). Both fasting and non‐fasting plasma triglycerides were lower (P= 0.003) in pigs fed MUFA‐rich diets, while the cholesterol profile was not significantly different between the treatments. The results fromin vitrocopper‐induced lipid peroxidation, expressed in terms of conjugated dienes, showed that low density lipoprotein (LDL) particles in postprandial serum from pigs fed olive oil were moderately more resistant to oxidative modification. In conclusion, these data demonstrate that both extra‐virgin and refined olive oils attenuate postprandial hypertriglyceridaemia, moderately affect oxidation susceptibility and increase bone mineral density in growing pigs. Copyright © 2006 Society of Chemical Industry
Effect of Mixed Sol‐Gel Precursors on the Metal‐Oxo Phase Within a UV‐Curable Silicone Hybrid Material
Authors: Dworak David P. , Soucek Mark D.
Published: July 2006

Summary: An inorganic hybrid material was produced using a polysiloxane binder and metal‐oxo‐clusters which were derived from sol‐gel precursors. The continuous phase is composed of an elastomeric polysiloxane functionalized with cycloaliphatic epoxide groups. Pendant alkoxy silane groups serve as a coupling agent to form a network between the metal‐oxo‐clusters and the crosslinked polysiloxane. Methyl, cyclopentyl, and cyclohexyl substituted polysiloxanes were formulated with a variety of sol‐gel precursors (tetraethylorthosilicate oligomers, titanium(IV) iso‐propoxide, zirconium(IV) propoxide, and zinc acetate). Phase‐modulated FT‐IR, X‐ray photoelectron spectroscopy, solid state 29Si NMR, and solid state 13C NMR were used to investigate the internal structure of the mixed metal‐oxo/silicon‐oxo colloids prepared within the cured polysiloxane matrix. Results indicate that the cycloaliphatic groups inhibit the complete hydrolysis and condensation of the pendant triethoxysilane group and reaction of the sol‐gel precursors. Analysis also indicated that the metal‐oxo‐clusters were comprised of mixed species of sol‐gel precursors resulting in hetero‐bonded (SiOMetal) colloids.

Possible network compositions of the cured material (a) specific metal‐oxo‐clusters, (b) hetero‐bonded metal‐oxo‐clusters, and (c) core/shell type metal‐oxo‐cluster configuration.

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Possible network compositions of the cured material (a) specific metal‐oxo‐clusters, (b) hetero‐bonded metal‐oxo‐clusters, and (c) core/shell type metal‐oxo‐cluster configuration.
Characterization of the Mode of Incorporation of Lipophilic Compounds in Solid Dispersions at the Nanoscale Using Fluorescence Resonance Energy Transfer (FRET)
Authors: van Drooge Dirk Jan , Braeckmans Kevin , Hinrichs Wouter L. J. , Remaut Katrien , De Smedt Stefaan C. , Frijlink Henderik W.
Published: July 2006

Summary: Efficient engineering of solid dispersions stagnates by the current inability to establish the mode of drug distribution on a molecular level at a low drug load. This study describes the application of fluorescence resonance energy transfer (FRET) to characterize the mode of incorporation of dispersed lipophilic molecules in a solid matrix. Two different lipophilic fluorophores (donor and acceptor) were used as model substances and were incorporated in polyvinylpyrrolidone to form solid dispersions using two different production processes: lyophilization and fusion. The efficiency of the resonance energy transfer from donor to acceptor was measured by confocal microscopy. We show that the method can be used to compare the modes of drug incorporation of solid dispersions at the nanoscale.

Absorption and emission spectra of Bodipy R6G (donor) and Bodipy 650/665 (acceptor).

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Absorption and emission spectra of Bodipy R6G (donor) and Bodipy 650/665 (acceptor).
Dissipative Particle Dynamics Study of the Formation of Multicompartment Micelles from ABC Star Triblock Copolymers in Water
Authors: Xia Jun , Zhong Chongli
Published: July 2006

Summary: Dissipative particle dynamics simulation was performed to study the formation of multicompartment micelles from ABC star triblock copolymers in water. The study revealed some new morphologies that had not been observed before and also provided a direct visualization of the evolution of wormlike multicompartment micelles that follows the fusion process. Thus, this work provides molecular understanding of multicompartment micelles which will be useful for the future rational synthesis of novel micelles.

Multicompartment micelles formed from ABC star triblock copolymers in water by DPD simulations.

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Multicompartment micelles formed from ABC star triblock copolymers in water by DPD simulations.
Preparation of Polystyrene‐Poly(N‐isopropylacrylamide) (PS‐PNIPA) Core‐Shell Particles by Photoemulsion Polymerization
Authors: Lu Yan , Wittemann Alexander , Ballauff Matthias , Drechsler Markus
Published: July 2006

Summary: Monodisperse thermosensitive PS‐NIPA core‐shell particles composed of a PS core and a cross‐linked PNIPA shell can be successfully synthesized by a novel method: photoemulsion polymerization. Cryo‐TEM images indicate clearly the core‐shell morphology of the PS‐NIPA particles: A homogeneous regular PNIPA shell has been affixed on the spherical PS core. DLS measurements indicate that the obtained PS‐NIPA latex particles are thermosensitive. The shell of PNIPA networks with different cross‐linking densities can shrink and re‐swell with temperature and the volume transition temperature is around 32 °C in all cases.

Cryo‐TEM image of PS‐NIPA core‐shell particles.

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Cryo‐TEM image of PS‐NIPA core‐shell particles.
Magnetic Molecularly Imprinted Polymer Particles Synthesized by Suspension Polymerization in Silicone Oil
Authors: Wang Xiaobing , Ding Xiaobin , Zheng Zhaohui , Hu Xinhua , Cheng Xu , Peng Yuxing
Published: July 2006

Summary: Magnetic nanoparticles have been prepared by a co‐precipitation method and modified with methacryloxypropyltrimethoxysilane. Magnetic molecularly imprinted polymer particles have been prepared by suspension polymerization in silicone oil. The particles possess a high affinity to the template molecules and are rapidly separated under a magnetic field.

SEM photograph of magnetic MIP particles.

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SEM photograph of magnetic MIP particles.
A Rational Approach to Crosslinking of Coordination Polymers Using the Photochemical [2+2] Cycloaddition Reaction
Authors: Nagarathinam Mangayarkarasi , Vittal Jagadese J.
Published: July 2006

Summary: Polymerization as a result of photocrosslinking is one of the most versatile technologies for producing organic polymers. This article highlights the formation of crosslinking in metal coordination polymers in the solid‐state using a photochemical approach and its importance in material science. Past and current developments of solid‐state photochemical [2+2] cycloaddition in organic and inorganic systems relevant to the topic are reviewed. The challenges for the coordination chemist in utilising this rational approach to orient the coordination polymers and the scope of this work are delineated.

The CC‐containing molecules can be aligned by metal coordination bonds in such a way as to promote crosslinking by a photochemical [2+2] cycloaddition reaction.

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The CC‐containing molecules can be aligned by metal coordination bonds in such a way as to promote crosslinking by a photochemical [2+2] cycloaddition reaction.
Breast cancer cells secreted platelet‐derived growth factor‐induced motility of vascular smooth muscle cells is mediated through neuropilin‐1
Authors: Banerjee Snigdha , Sengupta Krishanu , Dhar Kakali , Mehta Smita , D'Amore Patricia A. , Dhar Gopal , Banerjee Sushanta K.
Published: July 2006

Motility of vascular smooth muscle cells (SMCs) is an essential step for both normal and pathologic angiogenesis. We report here that breast tumor cells, such as MCF‐7 and MDA‐MB‐231, can modulate this SMC migration. We present evidence that the tumor cell‐derived platelet‐derived growth factor (PDGF) is the key regulator of vascular SMCs motility induced by breast cancer cells. PDGF significantly upregulates neuropilin‐1 (NRP‐1) mRNA expression and protein production in aortic smooth muscle cells (AOSMCs) and depletion of NRP‐1 production by AOSMCs with specific short hairpin RNA (shRNA) prevents the PDGF‐dependent migration of vascular SMCs. Moreover, we demonstrate that PDGF physically interacts with NRP‐1. We propose that tumor‐derived PDGF and NRP‐1 of AOSMCs function as a relay system that promotes motility of vascular SMCs. © 2006 Wiley‐Liss, Inc.