bluuebunny/crossref_metadata_2025 huggingface dataset:
Spin‐Crossover Studies on a Series of 1D Chain and Dinuclear Iron(II) Triazine‐Dipyridylamine Compounds
Authors: Neville Suzanne M. , Leita Ben A. , Offermann Daniel A. , Duriska Martin B. , Moubaraki Boujemaa , Chapman Karena W. , Halder Gregory J. , Murray Keith S.
Published: January 2007

Four isostructural one‐dimensional polymeric iron(II) spin crossover materials containing the ligand 2‐chloro‐4,6‐bis(dipyrid‐2‐ylamino)‐1,3,5‐triazine (cddt) have been synthesised and magnetically and structurally characterised. The polymeric material Fe(NCS)2(cddt)·n(guest) (1), self assembles into three crystallographically distinct phases; the compounds 1b and 1c, [Fe(NCS)2(cddt)]·2(CH3OH), are polymorphs, however, 1a, [Fe(NCS)2(cddt)]·1/2(CHCl3)·(H2O) contains a different solvent system. Each phase shows very different magnetic behaviour; phases 1a and 1b remain high spin over all temperatures, whilst phase 1c undergoes a “half” spin crossover between 225 and 125 K. The structural consequences of the spin transition in 1c have been followed using variable temperature synchrotron powder X‐ray diffraction techniques. Variation of the chalcogenide ligand in the complex [Fe(NCSe)2(cddt)]·2(CH3OH), 2, leads to a full one‐step spin crossover with a T1/2 of 200 K. Structural analysis of 1c below the transition temperature reveals alternating, crystallographically distinct, HS and LS iron(II) centres (HS: high spin, LS: low spin) along the chain, and structural analysis of 2 below the transition temperature reveals all LS iron(II) centres. Also reported are the structural characterisations of two dinuclear materials, containing the ligand 2,4,6‐tris(dipyridin‐2‐ylamino)‐1,3,5‐triazine (tdt), of the formula [Fe(tdt)(X)2]2·(ClO4)·(solvent) (X = H2O, Cl– for 3a, 3b) which are analogous to those recently reported by Gamez et al. In addition, the structural characterisations are described for dinuclear materials, containing the ligand cddt, of the formula [Fe(cddt)(Cl)(X)]2·(Y)2·n(solvent) (X: H2O or NCCH3, Y: ClO4–, BF4– 4a, 4b and 4d) and for a cobalt(II) analogue, [Co(cddt)(Cl)(H2O)]2·(BF4)2·n(solvent) (4c).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A microtiter plate‐based assay method to determine fat quality
Authors: Bertram Mark , Manschot‐Lawrence Corrine , Flöter Eckhard , Bornscheuer Uwe T.
Published: January 2007

A microtiter plate (MTP) method was developed to determine the quality of fats that are used in large‐scale processing using lipase catalysis. Two assay formats were followed: In the first approach, the fats were interesterified with p‐nitrophenol laurate using a lipase from Thermomyces lanuginosa; in the second approach, pH indicators were added to the fat samples containing lipase. A blind study using 29 fats showed that the MTP method using p‐nitrophenol as pH indicator allowed a rapid and reliable assignment of bad fats and an acceptable differentiation between fats of moderate and good quality.
Mild and Ligand‐Free Palladium‐Catalyzed Cross‐Couplings between Aryl Halides and Arylboronic Acids for the Synthesis of Biaryls and Heterocycle‐Containing Biaryls
Authors: Deng Chen‐Liang , Guo Sheng‐Mei , Xie Ye‐Xiang , Li Jin‐Heng
Published: January 2007

Ligand‐free palladium‐catalyzed Suzuki–Miyaura cross‐couplings between aryl halides and arylboronic acids performed at room temperature are presented. It was found that both solvent and base had a fundamental influence on the reaction, and the most effective system in terms of yield and rate was observed to be the combination of Pd(OAc)2 with MeONa and alcohols. In the presence of Pd(OAc)2 and MeONa, a variety of aryl halides reacted very rapidly with arylboronic acids in good to excellent yields at room temperature in EtOH as the solvent. Moreover, the Pd(OAc)2/MeONa catalytic system could also be applied in couplings between heteroaryl halides and arylboronic acids to provide satisfactory results in MeOH as the solvent after prolonged reaction times. It is noteworthy that the reactions were conducted under mild, aerobic, and ligand‐free conditions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
From Allenes to Tetracenes: A Synthetic and Structural Study of Silyl‐ and Halo‐Allenes and Their Dimers
Authors: Banide Emilie V. , Molloy Bevin C. , Ortin Yannick , Müller‐Bunz Helge , McGlinchey Michael J.
Published: January 2007

9‐Alkynylfluoren‐9‐ols of type C13H8(OH)–C≡C–R, where R is phenyl (1a), p‐tolyl (1b), p‐methoxyphenyl (1c), or trimethylsilyl (1d), react with HBr to yield the corresponding bromoallenes C12H8C=C=C(Br)R (13a–d). Lithiation and hydrolysis of 13d yields 3,3‐(biphenyl‐2,2′‐diyl)‐1‐(trimethylsilyl)allene (20), which forms successively the head‐to‐tail dimer 1‐(9‐fluorenylidene)‐4‐(trimethylsilyl)‐2‐[(trimethylsilyl)methylene]spiro[cyclobutane‐3,9′‐[9H]fluorene] (21) and the tail‐to‐tail dimer trans‐3,4‐bis(trimethylsilyl)‐1,2‐di(fluorenylidene)cyclobutane (23) both of which exhibit long (ca. 1.6 Å) C(3)–C(4) bonds. Treatment of 21 and 23 with TBAF brings about desilylation to 22 and 24, respectively. In the latter case, removal of the bulky trimethylsilyl groups reduces the C(3)–C(4) bond length in 1,2‐di(fluorenylidene)cyclobutane (24) to a more normal value of 1.547 Å; however, the large wingspan of the severely overlapping fluorenylidene moieties retains the C2 symmetry of the system. Prolonged exposure to sunlight of the disilylated head‐to‐tail dimer 21 results in homolysis of the long C(3)–C(4) bond, generation of a peroxide, and ultimately formation of the lactol 25. X‐ray crystallographic data are reported for, among others, 1c, 13a, 21, 22, 23, 24, 25, and also for 3,3‐(biphenyl‐2,2′‐diyl)‐1‐chloroallene (12).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Asymmetrical consequences of behavioral change through reward and punishment
Authors: Greitemeyer Tobias , Kazemi Ellie
Published: January 2007

Previous research (Greitemeyer & Weiner, 2003) has demonstrated that compliance, because of an anticipated reward is attributed more to the person than compliance because of an anticipated punishment. The present research extended these findings to an educational context. Three studies revealed that parents who ask their children to change inappropriate behaviors are more likely to ascribe their children's improvement to the child, if the child was promised a reward, rather than threatened, to receive a punishment if the child did not improve. Moreover, because a child's improved behavior is more likely to be ascribed to the child given a reward as compared to a punishment, parents expect that rewards (as opposed to punishments) are more likely to sustain improved behavior, when the incentive is no longer offered. Finally, participants report to be more likely to induce behavioral change through reward rather than punishment. Copyright © 2007 John Wiley & Sons, Ltd.
Attitude learning through exploration: advice and strategy appraisals
Authors: Eiser J. Richard , Shook Natalie J. , Fazio Russell H.
Published: January 2007

Processes of attitude learning were investigated through a game requiring discrimination between good and bad objects, where feedback about object valence (involving gain or loss) is contingent on approach. Previous research demonstrates a preponderance of false‐negative errors, with some good objects (‘learning asymmetry’) and most novel objects (‘generalization asymmetry’) being judged as bad, but provides no direct evidence concerning how participants appraise alternative strategies and their own performance. To compare alternative strategies, participants received advice, supposedly from a previous participant, that most objects were bad and should be avoided, or good and should be approached. Learning and generalization asymmetries were replicated, especially among participants who followed the former (risk‐averse) advice. Additionally, participants' evaluations of their own game strategy were inversely related to amount of negative feedback (the number of bad objects approached), but unrelated to positive feedback (from good objects approached), pointing to the salience of negative information for self‐appraisals. Copyright © 2007 John Wiley & Sons, Ltd.
Biodegradation of benzo[a]pyrene with immobilized laccase: Genotoxicity of the products in HaCat and A3 cells
Authors: Hu Xiaoke , Zhang Yi , Zhao Xueheng , Hwang Huey‐Min
Published: January 2007

Benzo[a]pyrene (BaP) is listed as a priority pollutant by the U.S. Environmental Protection Agency because it is one of the most potent carcinogens of all known polycyclic aromatic hydrocarbons (PAHs). The biodegradation of BaP is of interest as a means for mitigating its effects in polluted ecosystems. In the present study, BaP was oxidized with laccase from Trametes versicolor, which was immobilized on functionalized kaolinite particles, and the cytotoxicity and genotoxicity of BaP and its degradation intermediates were measured in human HaCaT keratinocytes and A3 T lymphocytes. Cytotoxicity was assessed by fluorescein diacetate (FDA) uptake, while the alkaline Comet assay measured genotoxicity, using tail moment, tail DNA content, and tail length as metrics for DNA damage. On the basis of first‐order reaction kinetics, the half life (t1/2) for the oxidization of BaP by immobilized laccase was 58.5 hr. After 87 hr of oxidation, 20 μM of BaP had decreased to 9.6 μM. HPLC analysis identified 1,6‐benzo[a]pyrene quinone (1,6‐BaQ), 3,6‐benzo[a]pyrene quinone (3,6‐BaQ), and 6,12‐benzo[a]pyrene quinone (6,12‐BaQ) among the oxidation products. Most treatments of HaCaT cells and A3 lymphocytes with BaP or its quinone intermediates resulted in significant decreases in viability (P < 0.05); dose‐dependent decreases in cell viability were detected at concentrations of 0.1, 1, and 5 μM, but none of these treatments resulted in decreases of >30%. While treatment of HaCaT cells with as little as 0.1 μM 6,12‐BaQ caused significant DNA damage, DNA damage was detected in HaCaT cells only with 1 and 5 μM 1,6‐BaQ and 3,6‐BaQ, and 5 μM BaP. In Comet assays conducted with A3 lymphocytes, all three quinone intermediates caused significant increase in tail DNA content at 1 and 5 μM. The results indicate that immobilized laccase is capable of degrading BaP, but several of those biodegradation products produce significant levels of DNA damage in human cells. Environ. Mol. Mutagen., 2007. © 2007 Wiley‐Liss, Inc.
An optimized Schwarz method with two‐sided Robin transmission conditions for the Helmholtz equation
Authors: Gander M. J. , Halpern L. , Magoulès F.
Published: January 2007

Optimized Schwarz methods are working like classical Schwarz methods, but they are exchanging physically more valuable information between subdomains and hence have better convergence behaviour. The new transmission conditions include also derivative information, not just function values, and optimized Schwarz methods can be used without overlap. In this paper, we present a new optimized Schwarz method without overlap in the 2d case, which uses a different Robin condition for neighbouring subdomains at their common interface, and which we call two‐sided Robin condition. We optimize the parameters in the Robin conditions and show that for a fixed frequency an asymptotic convergence factor of 1 – O(h1/4) in the mesh parameter h can be achieved. If the frequency is related to the mesh parameter h, h = O(1/ωγ) for γ⩾1, then the optimized asymptotic convergence factor is 1 – O(ω(1–2γ)/8). We illustrate our analysis with 2d numerical experiments. Copyright © 2007 John Wiley & Sons, Ltd.
Tumor microenvironment in head and neck squamous cell carcinomas: Predictive value and clinical relevance of hypoxic markers. A review
Authors: Hoogsteen Ilse J. , Marres Henri A. M. , Bussink Johan , van der Kogel Albert J. , Kaanders Johannes H. A. M.
Published: January 2007

Background.

Hypoxia and tumor cell proliferation are important factors determining the treatment response of squamous cell carcinomas of the head and neck. Successful approaches have been developed to counteract these resistance mechanisms although usually at the cost of increased short‐ and long‐term side effects. To provide the best attainable quality of life for individual patients and the head and neck cancer patient population as a whole, it is of increasing importance that tools be developed that allow a better selection of patients for these intensified treatments.

Methods.

A literature review was performed with special focus on the predictive value and clinical relevance of endogenous hypoxia‐related markers.

Results.

New methods for qualitative and quantitative assessment of functional microenvironmental parameters such as hypoxia, proliferation, and vasculature have identified several candidate markers for future use in predictive assays. Hypoxia‐related markers include hypoxia inducible factor (HIF)‐1α, carbonic anhydrase IX, glucose transporters, erythropoietin receptor, osteopontin, and others. Although several of these markers and combinations of markers are associated with treatment outcome, their clinical value as predictive factors remains to be established.

Conclusions:

A number of markers and marker profiles have emerged that may have potential as a predictive assay. Validation of these candidate assays requires testing in prospective trials comparing standard treatment against experimental treatments targeting the related microregional constituent. © 2007 Wiley Periodicals, Inc. Head Neck, 2007
Does a positive neural margin affect outcome in facial nerve grafting?
Authors: Wax Mark K. , Kaylie David M.
Published: January 2007

Background.

We sought to determine the effect of positive neural margins on subsequent facial nerve function following facial nerve grafting.

Methods.

In this retrospective review, 19 patients had sacrifice of their facial nerve with immediate facial nerve grafting, 8 had positive neural margins, and 11 had negative neural margins. Facial nerve function was analyzed using the House–Brackman scale.

Results.

In the first group (8 patients), 5 had positive proximal margins and 3 had positive distal neural margins. Outcome by House‐Brackman score was III (2 patients), IV (3 patients), V (1 patient), and VI (2 patients). In the second group (no evidence of neural spread, 11 patients), outcome was III (3 patients), IV (2 patients), V (2 patients), and VI (4 patients).

Conclusion.

No significant difference in the outcome of facial nerve function was seen between these 2 groups. Facial nerve grafting should be considered in patients whose facial nerve is sacrificed, even when there is evidence of tumor in the perineurium at the margin of resection. © 2007 Wiley Periodicals, Inc. Head Neck, 2007
Incidence of donor site skin graft loss requiring surgical intervention with the radial forearm free flap
Authors: Emerick Kevin S. , Deschler Daniel G.
Published: January 2007

Background.

Many methods of managing the fasciocutaneous radial forearm free flap (RFFF) donor site have been described. Ideal management would be technically easy to perform, reliable, cost‐effective, and prevent further complications.

Methods.

The clinical records of 54 consecutive patients undergoing RFFF surgery by the senior author were reviewed. Records were reviewed to identify donor sites with significant breakdown that required intervention.

Results.

Fifty‐four patients were identified. Only 1 patient had significant tendon exposure. A V to Y closure was performed. The site healed well following this procedure and no further intervention was required. No other donor site complications were noted in this group.

Conclusion.

The incidence of wound breakdown requiring surgical intervention at the RFFF donor site is less than 2% utilizing a simple technique of split thickness skin grafting, bolster, and short‐term splinting. This study demonstrates the low donor site morbidity of the RFFF. © 2007 Wiley Periodicals, Inc. Head Neck, 2007
Inverse flood risk modelling under changing climatic conditions
Authors: Cunderlik Juraj M. , Simonovic Slobodan P.
Published: January 2007

One of the most significant anticipated consequences of global climate change is the increased frequency of hydrologic extremes. Predictions of climate change impacts on the regime of hydrologic extremes have traditionally been conducted using a top‐down approach. The top‐down approach involves a high degree of uncertainty associated with global circulation model (GCM) outputs and the choice of downscaling technique. This study attempts to explore an inverse approach to the modelling of hydrologic risk and vulnerability to changing climatic conditions. With a focus targeted at end‐users, the proposed approach first identifies critical hydrologic exposures that may lead to local failures of existing water resources systems. A hydrologic model is used to transform inversely the main hydrologic exposures, such as floods and droughts, into corresponding meteorological conditions. The frequency of critical meteorological situations is investigated under present and future climatic scenarios by means of a generic weather generator. The weather generator, linked with GCMs at the last step of the proposed methodology, allows the creation of an ensemble of different scenarios, as well as an easy updating, when new and improved GCM outputs become available. The technique has been applied in Ontario, Canada. The results show significant changes in the frequency of hydro‐climatic extremes under future climate scenarios in the study area. Copyright © 2007 John Wiley & Sons, Ltd.
Enforced self‐organizing map neural networks for river flood forecasting
Authors: Chang Fi‐John , Chang Li‐Chiu , Wang Yan‐Shiang
Published: January 2007

Self‐organizing maps (SOMs) have been successfully accepted widely in science and engineering problems; not only are their results unbiased, but they can also be visualized. In this study, we propose an enforced SOM (ESOM) coupled with a linear regression output layer for flood forecasting. The ESOM re‐executes a few extra training patterns, e.g. the peak flow, as recycling input data increases the mapping space of peak flow in the topological structure of SOM, and the weighted sum of the extended output layer of the network improves the accuracy of forecasting peak flow. We have investigated an ESOM neural network by using the flood data of the Da‐Chia River, Taiwan, and evaluated its performance based on the results obtained from a commonly used back‐propagation neural network. The results demonstrate that the ESOM neural network has great efficiency for clustering, especially for the peak flow, and super capability of modelling the flood forecast. The topology maps created from the ESOM are interesting and informative. Copyright © 2007 John Wiley & Sons, Ltd.
Precipitation interception in Australian tropical rainforests: II. Altitudinal gradients of cloud interception, stemflow, throughfall and interception
Authors: McJannet David , Wallace Jim , Reddell Paul
Published: January 2007

This article presents a comprehensive study of canopy interception in six rainforests in Australia's Wet Tropics for periods ranging between 2 and 3·5 years. Measurements of rainfall, throughfall, stemflow and cloud interception were made at sites characterized by different forest types, canopy structure, altitude, rainfall and exposure to prevailing winds. Throughfall at these sites ranged between 64 and 83% of total precipitation inputs, while stemflow ranged between 2 and 11%. At sites higher than 1000 m, cloud interception was found to contribute up to 66% of the monthly water input to the forest, more than twice the rainfall at these times. Over the entire study period, cloud interception accounted for between 4 and 30% of total precipitation inputs, and was related more to the exposure of sites to prevailing winds than to altitudinal differences alone.

Over the duration of the study period, interception losses ranged between 22 and 29% of total water input (rainfall and cloud interception) at all sites except the highest altitude site on Bellenden Ker, where interception was 6% of total water input. This smaller interception loss was the result of extremely high rainfall, prolonged immersion in cloud and a sparser canopy. On a monthly basis, interception losses from the six sites varied between 10 and 88% of rainfall. All sites had much higher interception losses during the dry season than in the wet season because of the differences in storm size and rainfall intensity. The link between rainfall conditions and interception losses has important implications for how evaporative losses from forests may respond to altered rainfall regimes under climate change and/or large‐scale atmospheric circulation variations such as El Niño. Copyright © 2007 John Wiley & Sons, Ltd.
Precipitation interception in Australian tropical rainforests: I. Measurement of stemflow, throughfall and cloud interception
Authors: McJannet David , Wallace Jim , Reddell Paul
Published: January 2007

Methods for measuring throughfall, stemflow and, hence, interception in the tropical rainforests of the Wet Tropics region of North Queensland, Australia, were tested at three sites for between 581 and 787 days. The throughfall system design was based on long troughs mounted beneath the canopy and worked successfully under a range of rainfall conditions. Comparison of replicated systems demonstrated that the methodology is capable of capturing the variability in throughfall exhibited beneath our tropical rainforest canopies. Similarly, the stemflow system design which used spiral collars attached to sample trees worked well under a range of rainfall conditions and also produced similar estimates of stemflow in replicated systems.

Higher altitude rainforests (>1000 m) in North Queensland can receive significant extra inputs of water as the canopy intercepts passing cloud droplets. This additional source of water is referred to as ‘cloud interception’ and an instrument for detecting this is described. The results obtained from this gauge are compared with cloud interception estimates made using a canopy water balance method. This method is based on stemflow and throughfall measurements and provides an alternative means to fog or cloud interception gauge calibration techniques used in the literature. Copyright © 2007 John Wiley & Sons, Ltd.
An empirical model of daily highs and lows
Authors: Cheung Yin‐Wong
Published: January 2007

We construct an empirical model for daily highs and daily lows of US stock indexes based on the intuition that highs and lows do not drift apart over time. Our empirical results show that daily highs and lows of three main US stock price indexes are cointegrated. Data on openings, closings, and trading volume are found to offer incremental explanatory power for variations in highs and lows within the VECM framework. With all these variables, the augmented VECM models explain 40–50% of variations in daily highs and lows. The generalized impulse response analysis shows that the responses of daily highs and daily lows to the shocks depend on whether data on openings, closings, and trading volume are included in the analysis. Copyright © 2007 John Wiley & Sons, Ltd.
Exchange rates and fundamentals: a non‐linear relationship?
Authors: De Grauwe Paul , Vansteenkiste Isabel
Published: January 2007

We test whether the relationship between changes in the nominal exchange rate and changes in its underlying fundamentals has non‐linear features. In order to do so, we extend the Markov‐switching model as proposed by McConnell and Perez Quiros (2000) and Dewachter (2001) and test it using a sample of low‐ and high‐inflation countries. The empirical analysis shows that for the high‐inflation countries the relationship between news in the fundamentals and the exchange rate changes is stable and significant. This is not the case, however, for the low‐inflation countries, where frequent regime switches occur. We develop a non‐linear model based on the existence of transactions costs that could explain our empirical findings. We find that this simple non‐linear model is capable of replicating the empirical evidence uncovered in this paper. Copyright © 2007 John Wiley & Sons, Ltd.
Nickel release behavior, cytocompatibility, and superelasticity of oxidized porous single‐phase NiTi
Authors: Wu Shuilin , Liu Xiangmei , Chan Y.L. , Ho J.P.Y. , Chung C.Y. , Chu Paul K. , Chu C.L. , Yeung K.W.K. , Lu W.W. , Cheung K.M.C. , Luk K.D.K.
Published: January 2007

Porous NiTi shape memory alloys are one of the promising biomaterials for surgical implants because of their unique shape memory effects and porous structure with open pores. However, the complex surface morphology and larger area of porous NiTi compared to dense NiTi make it more vulnerable from the viewpoint of release of nickel, which can cause deleterious effects in the human body. It is also more difficult to modify the exposed surfaces of a porous structure using conventional surface modification technologies. In this work, oxidation in conjunction with postreaction heat treatment was used to modify the surfaces of porous single‐phase NiTi prepared by capsule‐free hot isostatic pressing to mitigate Ni leaching and enhance the surface properties. Differential scanning calorimetry thermal analysis, uniaxial compression tests, inductively‐coupled plasma mass spectrometry, and cell cultures reveal that porous NiTi alloys oxidized at 450°C for 1 h have an austenite transition temperature below 37°C, excellent superelasticity, lower nickel release, and no cytotoxicity. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Nanohydroxyapatite microspheres as delivery system for antibiotics: Release kinetics, antimicrobial activity, and interaction with osteoblasts
Authors: Ferraz M.P. , Mateus A.Y. , Sousa J.C. , Monteiro F.J.
Published: January 2007

Severe periodontitis treatment, where massive alveolar bone loss occurs, involves bone defect filling and intensive systemic log‐term antibiotics administration. This study aims at developing novel injectable drug delivery systems (nanohydroxyapatite microspheres) with the drug releasing capability for periodontitis treatment and simultaneously initiating the osteointegration process. Materials were characterized by XRD, SEM, inverted stand optical microscope analysis, and mercury porosimetry method. Amoxicillin, amoxicillin + clavulanic acid, and erythromycin were the antibiotics used. Release properties during 28 days from the hydroxyapatite (HA) granules, and two types of nanoHA microspheres were investigated. Biocompatibility was assessed by cytotoxicity assays. HA granules were inadequate, releasing all antibiotic during the first hours. The concentration of antibiotics released in the first days from HA‐2 was higher than from HA‐1 microspheres, because of the increased porosity and surface area. The release profiles (fast initial release followed by long‐term sustained release) of effective doses of antibiotics make these systems good alternatives for antibiotics delivery. Osteoblasts proliferated well on both types of microspheres, being cell growth enhanced in the presence of antibiotics. Erythromycin presented the most beneficial effect. Combining the sustained antibiotic release with the osteoconduction, resorbability, and potential use as injectable bone filling material of porous HA microspheres, these systems provided a forth fold beneficial effect. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Functional domains of the TGF‐β‐inducible transcription factor Tieg3 and detection of two putative nuclear localization signals within the zinc finger DNA‐binding domain
Authors: Spittau Björn , Wang Ziyuan , Boinska Dagmara , Krieglstein Kerstin
Published: January 2007

The recently identified TGF‐β‐inducible early gene 3 (Tieg3) belongs to the gene family of Sp1/Klf‐like transcription factors and is upregulated immediately after TGF‐β treatment. To explore the molecular mechanisms of Tieg3‐mediated transcriptional control, GAL4‐based luciferase assays were performed in order to determine regulatory domains within the Tieg3 protein. Using EGFP‐fusion proteins, we monitored the intracellular localization and mapped putative nuclear localization signals (NLS). We provide evidence that the amino‐terminus of Tieg3 is essential to repress the transcription and that the loss of the mSin3A interacting domain (SID) disrupts the repressive effects of Tieg3 in the oligodendroglial cell line OLI‐neu. Herein we also demonstrate that the zinc finger containing DNA‐binding domain (DBD) alone is able to activate the transcription of a reporter gene. Sequence analysis of the zinc finger region revealed no similarities to known activation domains. Analysis of the subcellular localization disclosed Tieg3 as a nuclear protein. Further, we identified the DBD as being essential for the nuclear localization of Tieg3. We detected two closely located putative bipartite NLS within the second and third zinc finger, which are conserved among the members of the Tieg family of proteins. Together these results may help to increase the understanding of Tieg3‐mediated transcriptional control and to characterize this TGF‐β‐induced Sp1/Klf‐like transcription factor. J. Cell. Biochem. 101: 712–722, 2007. © 2007 Wiley‐Liss, Inc.
Calculation of relative binding affinities of fructose 1,6‐bisphosphatase mutants with adenosine monophosphate using free energy perturbation method
Authors: Mutyala Ravichandra , Reddy R. N. , Sumakanth M. , Reddanna P. , Reddy M. Rami
Published: January 2007

The free energy perturbation (FEP) methodology is the most accurate means of estimating relative binding affinities between inhibitors and protein variants. In this article, the importance of hydrophobic and hydrophilic residues to the binding of adenosine monophosphate (AMP) to the fructose 1,6‐bisphosphatase (FBPase), a target enzyme for type‐II diabetes, was examined by FEP method. Five mutations were made to the FBPase enzyme with AMP inhibitor bound: 113Tyr → 113Phe, 31Thr → 31Ala, 31Thr → 31Ser, 177Met → 177Ala, and 30Leu → 30Phe. These mutations test the strength of hydrogen bonds and van der Waals interactions between the ligand and enzyme. The calculated relative free energies indicated that: 113Tyr and 31Thr play an important role, each via two hydrogen bonds affecting the binding affinity of inhibitor AMP to FBPase, and any changes in these hydrogen bonds due to mutations on the protein will have significant effect on the binding affinity of AMP to FBPase, consistent to experimental results. Also, the free energy calculations clearly show that the hydrophilic interactions are more important than the hydrophobic interactions of the binding pocket of FBPase. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Wet oxidation pretreatment of lignocellulosic residues of sugarcane, rice, cassava and peanuts for ethanol production
Authors: Martín Carlos , Thomsen Anne Belinda
Published: January 2007

Wet oxidation (WO) pretreatment of sugarcane bagasse, rice hulls, cassava stalks and peanut shells was investigated. WO was performed at 195 °C for 10 min, with 2 g kg−1 of Na2CO3 and under either 3 or 12 bar of oxygen. Oxygen pressure and the type of raw material used had a major effect on the fractionation of the materials, formation of sugars and by‐products, and cellulose enzymatic convertibility. Cellulose content in the solid fraction increased after pretreatment of all materials, except rice hulls. The greatest increase, from 361 g kg−1 to almost 600 g kg−1, occurred for bagasse. The solubilisation of individual components was different for each material. Bagasse xylan was solubilised to a large extent, and 45.2% of it was recovered as xylose and xylo‐oligosaccharides in the liquid fraction. In the prehydrolysates of rice hulls around 40% of the original glucan was recovered as gluco‐oligosaccharides, due to hydrolysis of starch contained in grain remains. The formation of by‐products was modest for all the materials, but increased with increasing oxygen pressure. The highest yield of acetic acid (34–36 g kg−1 of raw material) and furfural (0.7–1.8 g kg−1) occurred for bagasse. The pretreatment enhanced the enzymatic convertibility of cellulose giving the best result (670.2 g kg−1) for bagasse pretreated at the highest oxygen pressure. However, for the other materials the pretreatment conditions were not effective in achieving cellulose conversions above 450 g kg−1. Some enzymatic conversion of xylan was observed. Copyright © 2007 Society of Chemical Industry
Cr(VI) reduction by bio and bioinorganic catalysis via use of bio‐H2: a sustainable approach for remediation of wastes
Authors: Humphries Andrea C , Penfold David W , Macaskie Lynne E
Published: January 2007

Use of biologically‐produced hydrogen (bio‐H2) as an electron donor for Cr(VI) reduction by native and palladized cells of Desulfovibrio vulgaris NCIMB 8303 was demonstrated. The bio‐H2 was produced fermentatively by Escherichia coli HD701 (a strain upregulated with respect to formate hydrogenlyase expression) using glucose solution or two industrial confectionery wastes as fermentable substrates. Maximum Cr(VI) reduction occurred at the expense of bio‐H2 using palladized biomass (bio‐Pd(0)), with negligible residual Cr(VI) remaining from a 0.5 mmol dm−3 solution after 2.5 h. Use of bio‐H2 as the electron donor for Cr(VI) reduction by agar‐immobilized bio‐Pd(0) in a continuous‐flow system gave 90% reduction efficiency at a flow residence time of 0.7 h, which was maintained for the duration of bio‐H2 evolution by E. coli HD701. This study shows the potential to remediate toxic metal waste at the expense of food processing waste, as a sustainable alternative to landfilling. Copyright © 2007 Society of Chemical Industry
Implications of enhanced persistence of atmospheric circulation for the occurrence and severity of temperature extremes
Authors: Kyselý Jan
Published: January 2007

The relationship between persistent atmospheric circulation patterns over Europe and surface air temperature anomalies is studied for the 20th century using the Hess–Brezowsky catalogue of circulation types and temperature data from Prague. Circulation types significantly conducive to heat and cold waves are detected. It is demonstrated that the persistence of the circulation patterns is linked to surface air temperature anomalies and the occurrence and severity of temperature extremes that become more pronounced under more persistent circulation. The consequences vary for warm and cold extremes, depending on features related to atmospheric dynamics (e.g. air‐mass advection and fronts). The intensification of anomalies due to higher persistence of circulation patterns would likely be more important for warm temperature extremes than the cold ones. The recently observed increases in the frequency and severity of heat waves over Europe are likely related to enhanced persistence of the atmospheric circulation, and the impacts of the expected climate change on the occurrence and severity of temperature extremes may be exacerbated by more persistent circulation patterns over the European midlatitudes. Copyright © 2007 Royal Meteorological Society
New OSL dating of UK loess: indications of two phases of Late Glacial dust accretion in SE England and climate implications
Authors: Clarke Michèle L. , Milodowski Antoni E. , Bouch Jon E. , Leng Melanie J. , Northmore Kevin J.
Published: January 2007

Windblown dust deposits or loess, locally known in the UK as brickearth, blanket many parts of southern England outside the limits of the British and Irish Ice Sheet. The best‐studied loess exposures occur in Kent, southeast England, where the deposits are believed to be Late Glacial in age. New sedimentological evidence is presented for phases of accretion with two distinct units, a calcareous brickearth exhibiting periglacial cryoturbation and a non‐calcareous, massive brickearth. Optically stimulated luminescence (OSL) dating has been applied to chemically isolated modal quartz silts to derive a chronology for sediment accretion and to better understand the palaeoclimatic significance of these deposits. © British Geological Survey/Natural Environment Research Council copyright 2007. Reproduced with the permission of BGS/NERC. Published by John Wiley & Sons, Ltd.
Formalising an inversion methodology for reconstructing ice‐sheet retreat patterns from meltwater channels: application to the British Ice Sheet
Authors: Greenwood Sarah L. , Clark Chris D. , Hughes Anna L. C.
Published: January 2007

Glacial meltwater channels yield important information regarding patterns of palaeo‐ice‐sheet retreat. However, it is important to distinguish between channels formed at different positions in relation to the ice mass (e.g. lateral, subglacial). In Britain, whilst meltwater channels have been widely reported in the literature, such categorisation is often lacking. Here we develop an inversion methodology for extracting ice margin retreat patterns from meltwater channels. Diagnostic geomorphological criteria are presented, derived from published descriptions of meltwater channel form, by which a channel of unknown origin may be assigned to its appropriate category. These criteria are applied to channels recorded in the BRITICE GIS database of glacial landforms and we find most channels to be of lateral or subglacial origin. The categorisation of channels enables palaeomargin positions and the direction of retreat‐stage ice flow to be approximated, and a preliminary reconstruction is made of fragments of the ice‐sheet retreat pattern. Further mapping and integration of melt traces with other geomorphic data will permit a more complete palaeo‐glaciological reconstruction of the last British Ice Sheet. Copyright © 2007 John Wiley & Sons, Ltd.
Dynamic reduction of a CH4/air chemical mechanism appropriate for investigating vortex–flame interactions
Authors: Tonse Shaheen R. , Day Marcus S. , Brown Nancy J.
Published: January 2007

This paper describes two methods, piecewise reusable implementation of solution mapping (PRISM) and dynamic steady‐state approximation (DYSSA), in which chemistry is reduced dynamically to reduce the computational burden in combustion simulations. Each method utilizes the large range in species timescales to reduce the dimensionality to the number of species with slow timescales. The methods are applied within a framework that uses hypercubes to partition multidimensional chemical composition space, where each chemical species concentration, plus temperature, is represented by an axis in space. The dimensionality of the problem is reduced uniquely in each hypercube, but the dimensionality of chemical composition space is not reduced. The dimensionality reduction is dynamic and is different for different hypercubes, thereby escaping the restrictions of global methods in which reductions must be valid for all chemical mixtures. PRISM constructs polynomial equations in each hypercube, replacing the chemical kinetic ordinary differential equation (ODE) system with a set of quadratic polynomials with terms related to the number of species with slow timescales. Earlier versions of PRISM were applied to smaller chemical mechanisms and used all chemical species concentrations as terms. DYSSA is a dynamic treatment of the steady‐state approximation and uses the fast–slow timescale separation to determine the set of steady‐state species in each hypercube. A reduced number of chemical kinetic ODEs are integrated rather than the original full set. PRISM and DYSSA are evaluated for simulations of a pair of counterrotating vortices interacting with a premixed CH4/air laminar flame. DYSSA is sufficiently accurate for use in combustion simulations, and when relative errors are less than 1.0%, speedups on the order of 3 are observed. PRISM does not perform as well as DYSSA with respect to accuracy and efficiency. Although the polynomial evaluation that replaces the ODE solver is sufficiently fast, polynomials are not reused sufficiently to enable their construction cost to be recovered. © 2007 Wiley Periodicals, Inc. 39: 204–220, 2007
Direct ab initio dynamics calculations of the rate constants for the reaction of CHF2CF2OCH3 with Cl
Authors: Yang Lei , He Hong‐Qing , Ji Yue‐Meng , Liu Jing‐Yao , Li Ze‐Sheng
Published: January 2007

A dual‐level direct dynamics method is employed to reveal the dynamical properties of the reaction of CHF2CF2OCH3 (HFE‐254pc) with Cl atoms. The optimized geometries and frequencies of the stationary points and the minimum energy path (MEP) are calculated at the B3LYP/6‐311G(d,p) level by using GAUSSIAN 98 program package, and energetic information is further refined by the G3(MP2) method. Two H‐abstraction channels have been identified. For the reactant CHF2CF2OCH3 and the two products, CHF2CF2OCH2 and CF2CF2OCH3, the standard enthalpies of formation are evaluated with the values of −256.71 ± 0.88, −207.79 ± 0.12, and −233.43 ± 0.88 kcal/mol, respectively, via group‐balanced isodesmic reactions. The rate constants of the two reaction channels are evaluated by means of canonical variational transition‐state theory (CVT) including the small‐curvature tunneling (SCT) correction over a wide range of temperature from 200 to 2000 K. The calculated rate constants agree well with the experimental data, and the Arrhenius expressions for the title reaction are fitted and can be expressed as k1 = 9.22 × 10−19 T2.06 exp(219/T), k2 = 4.45 × 10−14 T0.90 exp(−2220/T), and k = 4.71 × 10−22 T3.20) exp(543/T) cm3 molecule−1 s−1. Our results indicate that H‐abstraction from CH3 group is the main reaction pathway in the lower temperature range, while H‐abstraction from CHF2 group becomes more competitive in the higher temperature range. © 2007 Wiley Periodicals, Inc. 39: 221–230, 2007
Managing knowledge in times of organisational change and restructuring
Authors: Armistead Colin , Meakins Magda
Published: January 2007

During times of organisational change and restructuring, processes and people are all affected to varying degrees. Within this context the ability to ‘manage’ knowledge is important, if the outcomes of business competitiveness are to be realised. This paper builds on previous research investigating the approaches of companies to knowledge and process management. Using the Royal Mail as a case study, managers' perceptions of knowledge management in times of change and restructuring were explored using a framework, which suggests ways of evaluating approaches to knowledge, depending on whether the context involves changes in people or processes. Finally the framework was evaluated with managers to establish its usefulness in informing approaches to managing knowledge in times of restructuring. Copyright © 2007 John Wiley & Sons, Ltd.
Metrics‐based process redesign with the MIT Process Handbook
Authors: Margherita Alessandro , Klein Mark , Elia Gianluca
Published: January 2007

This article describes how the business process re‐engineering (BPR) concepts, knowledge base and software tools developed as part of the MIT Process Handbook can be extended and improved through the use of a systematic taxonomization of business process metrics. After introducing the key concepts underlying the Handbook, we propose a taxonomy of cost, dimension and value‐related process metrics and show how the capture of such measures, combined with a set of special query types, enables more effective BPR. These innovations are illustrated using an example wherein the manager of a travel agency redesigns a booking process to reduce costs and increase customer satisfaction. Copyright © 2007 John Wiley & Sons, Ltd.
Low‐power laser stimulation of tissue engineered cartilage tissue formed on a porous calcium polyphosphate scaffold
Authors: Gan Lu , Tse Carmen , Pilliar Robert M. , Kandel Rita A.
Published: January 2007

Background and Objective

Forming cartilage tissue in vitro that resembles native tissue is one of the challenges of cartilage tissue engineering. The aim of this study was to determine whether low‐power laser stimulation would improve the formation of cartilage tissue in vitro.

Study Design/Materials and Methods

Bovine articular chondrocytes were seeded on the top surface of porous calcium polyphosphate substrates. After 2 days, laser stimulation was applied daily at a wavelength of 650 nm using a laser diode with energy densities of either 1.75 or 3 J/cm2 for 4 weeks. Proteoglycan and collagen synthesis and matrix content were determined. Cartilage tissue morphology was evaluated histologically.

Results

Histologically, there was no difference in the appearance or cellularity of the tissues that formed in the presence or absence of laser stimulation at either dosage. There were no differences in DNA content between treated and untreated constructs and live‐dead assay confirmed that this treatment was not toxic to the cells. Laser stimulation at 3 J/cm2 enhanced matrix synthesis resulting in significantly more tissue formation than laser stimulation at 1.75 J/cm2 or untreated cultures.

Conclusion

Short exposures to low‐power laser stimulation using a laser diode with 3 J/cm2 dose improves cartilage tissue formation. Lasers Surg. Med. 39:286–293, 2007. © 2007 Wiley‐Liss, Inc.
Fluorinated Hyperbranched Polyimide for Optical Waveguides
Authors: Gao Hong , Wang Dong , Guan Shaowei , Jiang Wei , Jiang Zhenhua , Gao Weinan , Zhang Daming
Published: January 2007

A novel fluorinated hyperbranched polyimide (HBPI) is synthesized by using a new triamine monomer, 1,3,5‐tris(2‐trifluoromethyl‐4‐aminophenoxy)benzene (TFAPOB) (A3), as a ‘core’ molecule, 4,4‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) as a B2 monomer, and 3,5‐ditrifuoromethylphenyl as an endcapping reagent. The polymer shows a glass transition temperature of 232 °C and a temperature of 10% weight loss at 535 °C. The HBPI presents a birefringence as low as 0.002 at 650 nm. Near‐IR results indicate that HBPI exhibits desirable properties for low loss optical waveguide applications.

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Spatial substituent effects of various fluorinated groups on the 13C chemical shifts in cyclohexanes
Authors: Carcenac Yvan , Diter Patrick , Wakselman Claude , Tordeux Marc
Published: January 2007

The effect of introduction of fluorinated groups (CH2F, CHF2, CF3, C2F5, OCF3, SCF3) on the 13C NMR chemical shifts in cyclohexanes is examined. The two main effects are caused by location at the α and γ carbon positions. Comparison of the various data allowed the calculation of increments corresponding to the introduction of fluorinated groups at axial or equatorial positions on the cyclohexane ring. The introduction of fluorine atoms in methoxy and thiomethoxy groups has only a slight effect through the heteroatom on the 13C chemical shifts. Copyright © 2007 John Wiley & Sons, Ltd.