bluuebunny/crossref_metadata_2025 huggingface dataset:
LKB1/PEA3/ΔNp63 Pathway Regulates PTGS‐2 (COX‐2) Transcription in Lung Cancer Cells Upon Cigarette Smoke Exposure
Authors: Ratovitski Edward A.
Published: February 2011

This is the first study to show that cigarette smoking induced the LKB1/PEA 3/ΔNp63‐dependent transcriptional regulation of inflammatory molecules, such as COX‐2/PTGS‐2. Using mainstream smoke extract (MSE) and sidestream smoke extract (SSE) as modeling tools for primary and secondhand smoking, we found that both MSE and SSE downregulated protein levels for LKB1, while upregulated protein levels for PEA 3 and COX‐2 in a dose‐dependent manner. Using the endogenous ChIP analysis, we further found that the C/EBPβ, NFκB, NF‐Y (CHOP), PEA 3 (ETS) and ΔNp63 proteins bound to the specific area (‐550 to ‐130) of the COX‐2 promoter, while forming multiple protein complexes in lung cancer cells exposed to MSE and SSE. Our results define a novel link between various transcription factors occupying the COX‐2 promoter and cellular response to cigarette smoke exposure bringing a new component, ΔNp63α, showing a critical role for cooperation between various chromatin components in regulation of COX‐2 expression and, therefore strengthening the central role of inflammatory process in tumorigenesis of epithelial cells, especially after cigarette smoke exposure (both primary and secondhand).
Harmine and Imipramine Promote Antioxidant Activities in Prefrontal Cortex and Hippocampus
Authors: Réus Gislaine Z. , Stringari Roberto B. , de Souza Bruna , Petronilho Fabrícia , Dal-Pizzol Felipe , Hallak Jaime E. , Zuardi Antônio W. , Crippa José A. , Quevedo João
Published: February 2011

A growing body of evidence has suggested that reactive oxygen species (ROS) may play an important role in the physiopathology of depression. Evidence has pointed to the β‐carboline harmine as a potential therapeutic target for the treatment of depression. The present study we evaluated the effects of acute and chronic administration of harmine (5, 10 and 15 mg/kg) and imipramine (10, 20 and 30 mg/kg) or saline in lipid and protein oxidation levels and superoxide dismutase (SOD) and catalase (CAT) activities in rat prefrontal cortex and hippocampus. Acute and chronic treatments with imipramine and harmine reduced lipid and protein oxidation, compared to control group in prefrontal cortex and hippocampus. The SOD and CAT activities increased with acute and chronic treatments with imipramine and harmine, compared to control group in prefrontal cortex and hippocampus. In conclusion, our results indicate positive effects of imipramine antidepressant and β‐carboline harmine of oxidative stress parameters, increasing SOD and CAT activities and decreasing lipid and protein oxidation.
Fluctuations in Brain Temperature Induced by Lypopolysaccharides: Central and Peripheral Contributions
Authors: Tang Jeremy S. , Kiyatkin Eugene A.
Published: February 2011

In this study, we examined changes in central (anterior‐preoptic hypothalamus) and peripheral (temporal muscle and facial skin) temperatures in freely moving rats following intravenous administration of bacterial lipopolysaccharides (LPS) at low doses (1 and 10 μg/kg) at thermoneutral conditions (28˚C). Recordings were made with high temporal resolution (5‐s bin) and the effects of LPS were compared with those induced by a tail‐pinch, a standard arousing somato‐sensory stimulus. At each dose, LPS moderately elevated brain, muscle and skin temperatures. In contrast to rapid, monophasic and relatively short hyperthermic responses induced by a tail‐pinch, LPS‐induced increases in brain and muscle temperatures occurred with ~40 min onset latencies, showed three not clearly defined phases, were slightly larger with the 10 μm/kg dose and maintained for the entire 4‐hour post‐injection recording duration. Based on dynamics of brain‐muscle and skin‐muscle temperature differentials, it appears that the hyperthermic response induced by LPS at the lowest dose originates from enhanced peripheral heat production, with no evidence of brain metabolic activation and skin vasoconstriction. While peripheral heat production also appears to determine the first phase of brain and body temperature elevation with LPS at 10 μg/kg, a further prolonged increase in brain‐muscle differentials (onset at ~100 min) suggests metabolic brain activation as a factor contributing to brain and body hyperthermia. At this dose, skin temperature increase was weaker than in temporal muscle, suggesting vasoconstriction as another contributor to brain/ body hyperthermia. Therefore, although both LPS at low doses and salient sensory stimuli moderately increase brain and body temperatures, these hyperthermic responses have important qualitative differences, reflecting unique underlying mechanisms.
Efficacy of Combination Therapy with Telmisartan Plus Amlodipine in Patients with Poorly Controlled Hypertension
Authors: Bekki Hisatoshi , Yamamoto Kiichiro , Sone Masayoshi , Homma Tomoki , Nakata Masashi , Nohara Masatoshi , Fukami Kei , Okuda Seiya , Yamagish Sho-ichi
Published: February 2011

There is accumulating evidence that blood pressure (BP) control significantly reduces the risk of future cardiovascular events in patients with essential hypertension. However, strict BP control is often difficult to maintain, and half of hypertensive patients fail to attain BP goals on single‐drug therapy. Therefore, current guidelines recommend combinations of drugs that have complimentary mode of actions for treatment of patients with moderate hypertension. In this study, we examined in hypertensive patients uncontrolled by the combination treatment with 5 mg amlodipine plus 80 mg valsartan or 8 mg candesartan whether additional BP lowering could be achieved by switching to 5 mg amlodipine plus 40 mg telmisartan. Forty‐seven patients with essential hypertension who failed to achieve a target BP level by the treatment of 5 mg amlodipine plus 80 mg valsartan or 8 mg candesartan for at least 2 months were enrolled. Replacement of valsartan or candesartan by telmisartan showed a significant reduction in both mean clinic systolic and diastolic BP at 4, 8 and 12 weeks; BP level decreased from 143.7/82.3 mmHg at baseline to 135.4/77.5 mmHg at 12 weeks. Furthermore, in 8 patients of valsartan group, switching to telmisartan significantly reduced central BP by 11.8 mmHg. Our present study suggests that combination therapy with telmisartan plus amlodipine may be more beneficial than valsartan or candesartan plus amolodipine treatment for controlling brachial and central BP, which could lead to more favorable cardiovascular outcomes with this drug combinations.
Pericytopathy: Oxidative Stress and Impaired Cellular Longevity in the Pancreas and Skeletal Muscle in Metabolic Syndrome and Type 2 Diabetes
Authors: Hayden Melvin R. , Yang Ying , Habibi Javad , Bagree Sarika V. , Sowers James R.
Published: February 2011

The pericyte′s role has been extensively studied in retinal tissues of diabetic retinopathy; however, little is known regarding its role in such tissues as the pancreas and skeletal muscle. This supportive microvascular mural cell plays an important and novel role in cellular and extracellular matrix remodeling in the pancreas and skeletal muscle of young rodent models representing the metabolic syndrome and type 2 diabetes mellitus (T2DM). Transmission electron microscopy can be used to evaluate these tissues from young rodent models of insulin resistance and T2DM, including the transgenic Ren2 rat, db/db obese insulin resistantߞT2DM mouse, and human islet amyloid polypeptide (HIP) rat model of T2DM. With this method, the earliest pancreatic remodeling change was widening of the islet exocrine interface and pericyte hypercellularity, followed by pericyte differentiation into islet and pancreatic stellate cells with early fibrosis involving the islet exocrine interface and interlobular interstitium. In skeletal muscle there was a unique endothelial capillary connectivity via elongated longitudinal pericyte processes in addition to pericyte to pericyte and pericyte to myocyte cellcell connections allowing for paracrine communication. Initial pericyte activation due to moderate oxidative stress signaling may be followed by hyperplasia, migration and differentiation into adult mesenchymal cells. Continued robust oxidative stress may induce pericyte apoptosis and impaired cellular longevity. Circulating antipericyte autoantibodies have recently been characterized, and may provide a screening method to detect those patients who are developing pericyte loss and are at greater risk for the development of complications of T2DM due to pericytopathy and rarefaction. Once detected, these patients may be offered more aggressive treatment strategies such as
early pharmacotherapy in addition to lifestyle changes targeted to maintaining pericyte integrity. In conclusion, we have provided a review of current knowledge regarding the pericyte and novel ultrastructural findings regarding its role in metabolic syndrome and T2DM.
Estimating urban heat island effects on near-surface air temperature records of Uccle (Brussels, Belgium): an observational and modeling study
Authors: Hamdi R. , Van de Vyver H.
Published: February 2011

Abstract. In this letter, the Brussels's urban heat island (UHI) effect on the near-surface air temperature time series of Uccle (the national suburban recording station of the Royal Meteorological Institute of Belgium) was estimated between 1955 and 2006 during the summer months. The UHI of Brussels was estimated using both ground-based weather stations and remote sensing imagery combined with a land surface scheme that includes a state-of-the-art urban parameterization, the Town Energy Balance scheme. Analysis of urban warming based on the remote sensing method reveals that the urban bias on minimum air temperature is rising at a higher rate, 2.5 times (2.85 ground-based observed) more, than on maximum temperature, with a linear trend of 0.15 °C (0.19 °C ground-based observed) and 0.06 °C (0.06 °C ground-based observed) per decade respectively. The summer-mean urban bias on the mean air temperature is 0.8 °C (0.9 °C ground-based observed). The results based on remote sensing imagery are compatible with estimates of urban warming based on weather stations. Therefore, the technique presented in this work is a useful tool in estimating the urban heat island contamination in long time series, countering the drawbacks of an ground-observational approach.
Low-frequency variability of European runoff
Authors: Gudmundsson L. , Tallaksen L. M. , Stahl K. , Fleig A. K.
Published: February 2011

Abstract. This study investigates the low-frequency components of observed monthly runoff in Europe, to better understand the runoff response to long-term variations in the climate system. The relative variance and the dominant space-time patterns of the low-frequency components of runoff were considered, in order to quantify their relative importance and to get insights in to the controlling factors. The analysis of a recently updated European data set of observed streamflow and corresponding time series of precipitation and temperature, showed that the fraction of low-frequency variance of runoff is on average larger than, and not correlated to, the fraction of low-frequency variance of precipitation and temperature. However, it is correlated with catchment properties as well as mean climatic conditions. The fraction of low-frequency variance of runoff decreases for catchments that respond more directly to precipitation. Furthermore, it increases (decreases) under drier (wetter) conditions – indicating that the average degree of catchment saturation may be a primary control of low-frequency runoff dynamics. The dominant space-time patterns of low-frequency runoff, identified using nonlinear dimension reduction, revealed that low-frequency runoff can be described with three modes, explaining together 80.6% of the variance. The dominant mode has opposing centers of simultaneous variations in northern and southern Europe. The secondary mode features a west-east pattern and the third mode has its centre of influence in central Europe. All modes are closely related to the space-time patterns extracted from time series of precipitation and temperature. In summary, it is shown that the dynamics of low-frequency runoff follows large-scale atmospheric features, whereas the proportion of variance attributed to low-frequency fluctuations is controlled by catchment processes and varies with the mean climatic conditions. The results may have implications for interpreting the impact of changes in temperature and precipitation on river-flow dynamics.
Ricoeur and the Symbolic Roots of Religious Experience
Authors: Starkey John
Published: February 2011

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Systematic Theology After Ricoeur
Authors: Stiver Dan R.
Published: February 2011

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Table of Contents
Authors: Editors JFFP
Published: February 2011

Table of Contents from the print version
Translators' Introduction
Authors: Cohn Jesse S , Jun Nathan J.
Published: February 2011

none
Contact and Submission Information
Authors: Editors JFFP
Published: February 2011

Back materials from print version
Happiness is Not Fun: Godard, the 20th Century, and Badiou
Authors: Walsh Michael
Published: February 2011

"Godard is the most contemporary of directors, one who has never set a film in the past. Yet since the 1990s he has produced a whole cycle of works whose tones are retrospective, memorial, elegaic. These include JLG/JLG:Auto-portrait du Décembre (1995), the much-discussed Histoire(s) du Cinèma (begun in 1988, completed in 1998) 2 x 50 Years of French Cinema (commissioned by the BFI for the centennial of cinema in 1995), The Old Place (commissioned by the Museum of Modern Art in 1999), On the Origin of the Twenty-First Century (commissioned by the Cannes Film Festival for the year 2000), Dans Le Noir du Temps (a contribution to the 2002 compilation film Ten Minutes Older), and the 2006 Centre Pompidou exhibition “Travels in Utopia.” This last was a retrospective in the conventional sense (screenings of four decades worth of film and video by Godard, Godard/Gorin, Godard/Mièville, etc), but was also retrospective as an installation, divided into three spaces identified as hier, l’avant-hier, and aujourd’hui (yesterday, the day before yesterday, and today), with tomorrow notable for its absence..."
Masthead
Authors: Editors JFFP
Published: February 2011

Masthead from the print version
COMPARISON OF SINE VERSUS PULSE WAVEFORM EFFECTS ON FATIGUE CRACK GROWTH BEHAVIOR OF NR, SBR, AND BR COMPOUNDS
Authors: Andreini G. , Straffi P. , Cotugno S. , Gallone G. , Polacco G.
Published: February 2011

Fatigue crack growth experiments on carbon black-filled rubber compounds have been carried out to evaluate the influence of testing conditions over different compound formulations. Investigations on the influence of waveform, data acquisition, and compound formulation have been performed on strip-tensile specimens reproducing the mode I of crack opening. The response of three different compound formulations (based on either natural rubber, butadiene rubber, or styrene-butadiene rubber) to the application of two different waveforms, pulse and sine, has been analyzed, showing significant differences in fatigue behavior and ranking of the various compounds. Compared to the sinusoidal waveform, the use of a pulse waveform provided an improved correlation of the tearing energy with the crack propagation speed. This difference was particularly evident in the case of natural rubber and butadiene rubber, while it resulted negligible in the case of styrene-butadiene rubber. Such a different behavior could be attributed to differences in macromolecular chains orientation. Fine-tuning of video acquisition parameters provided an accurate observation of the crack growth process, as confirmed by the low standard deviation of the estimated tearing energy and crack growth rate.
Spinodal Decomposition of Blends of Semiconducting and Ferroelectric Polymers
Authors: Asadi Kamal , Wondergem Harry J. , Moghaddam Reza Saberi , McNeill Christopher R. , Stingelin Natalie , Noheda Beatriz , Blom Paul W. M. , de Leeuw Dago M.
Published: February 2011

The operation of resistive switches based on phase‐separated blends of organic ferroelectrics and semiconductors depends significantly on the microstructure of such systems. A wide range of analysis techniques are used to characterize spin‐coated films of the ferroelectric random copolymer poly(vinylidene fluoride‐trifluoroethylene) [P(VDF‐TrFE)], and the semiconducting polymer, regio‐irregular poly(3‐hexylthiophene) (rir‐P3HT). The blend separates into amorphous rir‐P3HT domains embedded in a crystalline P(VDF‐TrFE) matrix. The rir‐P3HT domains are continuous throughout the film, from the substrate/blend interface to the blend/air interface. We also investigate the rir‐P3HT domain size and number as a function of composition and find – unexpectedly – a rather mono‐disperse domain size distribution for a given rir‐P3HT:P(VDF‐TrFE) ratio. The domain size increases with rir‐P3HT content, indicating that the solidification is not dominated by nucleation processes. Spinodal decomposition is therefore more likely to be responsible for the microstructure induced in the rir‐P3HT:P(VDF‐TrFE) blends. Since spinodal decomposition occurs spontaneously without the presence of a nucleation step, this can facilitate processing considerably, since the intricate control of nucleation processes (homogenous or heterogenous) is rendered unnecessary. Measurement of the lateral conductivity of the blends demonstrates that the rir‐P3HT domains are electrically not connected, supporting the microstructural evidence. A perpendicular current through the film is measured using both Au and Ag electrodes as a function of blend composition. A model was used to interpret the electrical transport. The injection for Ag diodes poled into the ON‐state preferentially occurs at the circumference of the rir‐P3HT domains. An accumulation width over which the injection occurs is estimated to be of the order of a few hundred nm.
Errichtung und Zurechnung von Ressortforschungseinrichtungen. Eine Frage des Bedarfs an wissenschaftlicher Expertise?
Authors: Philipps Axel
Published: February 2011

The Constitution and Attribution of Government Research Agencies. A Matter of Need for Science‐generated Policy Knowledge? Government research agencies are a form of extra‐university research institutions. In contrast to other extra‐university research facilities they are subordinate to and financed by respective German governmental departments. As their mission they provide science‐generated information, services, and monitoring to support the governmental departments. In science studies researchers proclaim a rigid association between the installation, attribution, and development of government research agencies and the increasing need for science‐generated policy knowledge. The article examines this assumed association based on the personal, institutional, financial, and mission specific development of government research agencies between the years 1965 and 2005. According to the results the expansion of government research agencies stagnates – like science in general.
Elastic phantoms generated by microfluidics technology: Validation of an imaged‐based approach for accurate measurement of the growth rate of lung nodules
Authors: El‐Baz Ayman , Sethu Palaniappan , Gimel'farb Georgy , Khalifa Fahmi , Elnakib Ahmed , Falk Robert , El‐Ghar Mohamed Abo
Published: February 2011

This paper focuses on validating our approach for monitoring the development of lung nodules detected in successive chest low‐dose computed tomography (LDCT) scans of a patient. Our methodology for monitoring detected lung nodules includes 3D LDCT data registration, which is a non‐rigid technique and involves two steps: (i) global target‐to‐prototype alignment of one scan to another using the experience gained from a prior appearance model, followed by (ii) local alignment to correct for intricate relative deformations. We propose a new approach for validating the accuracy of our algorithm for elastic lung phantoms constructed with state‐of‐the‐art microfluidics technology and in vivo data. Fabricated from a flexible transparent polymer, i.e. polydimethylsiloxane (PDMS), the phantoms mimic the contractions and expansions of the lung and nodules as seen during normal breathing. The in vivo data in our study had been collected from a small control group of four subjects and a larger test group of 27 subjects with known ground truth (biopsy diagnosis. The growth rate and diagnostic results for both phantoms and in vivo data confirm the high accuracy of our algorithm.
Metabolic engineering of Corynebacterium glutamicum for production of 1,5‐diaminopentane from hemicellulose
Authors: Buschke Nele , Schröder Hartwig , Wittmann Christoph
Published: February 2011

In the present work, the bio‐based production of 1,5‐diaminopentane (cadaverine), an important building block for bio‐polyamides, was extended to hemicellulose a non‐food raw material. For this purpose, the metabolism of 1,5‐diaminopentane‐producing Corynebacterium glutamicum was engineered to the use of the C5 sugar xylose. This was realized by heterologous expression of the xylA and xylB genes from Escherichia coli, mediating the conversion of xylose into xylulose 5‐phosphate (an intermediate of the pentose phosphate pathway), in a defined diaminopentane‐producing C. glutamicum strain, recently obtained by systems metabolic engineering. The created mutant, C. glutamicum DAP‐Xyl1, exhibited efficient production of the diamine from xylose and from mixtures of xylose and glucose. Subsequently, the novel strain was tested on industrially relevant hemicellulose fractions, mainly containing xylose and glucose as carbon source. A two‐step process was developed, comprising (i) enzymatic hydrolysis of hemicellulose from dried oat spelts, and (ii) biotechnological 1,5‐diaminopentane production from the obtained hydrolysates with the novel C. glutamicum strain. This now opens a future avenue towards bio‐based 1,5‐diaminopentane and bio‐polyamides thereof from non‐food raw materials.
Atomic layer deposition of titanium dioxide on cellulose acetate for enhanced hemostasis
Authors: Hyde G. Kevin , Stewart S. Michael , Scarel Giovanna , Parsons Gregory N. , Shih Chun‐Che , Shih Chun‐Ming , Lin Shing‐Jong , Su Yea‐Yang , Monteiro‐Riviere Nancy A. , Narayan Roger J.
Published: February 2011

TiO2 films may be used to alter the wettability and hemocompatibility of cellulose materials. In this study, pure and stoichiometric TiO2 films were grown using atomic layer deposition on both silicon and cellulose substrates. The films were grown with uniform thicknesses and with a growth rate in agreement with literature results. The TiO2 films were shown to profoundly alter the water contact angle values of cellulose in a manner dependent upon processing characteristics. Higher amounts of protein adsorption indicated by blurry areas on images generated by scanning electron microscopy were noted on TiO2‐coated cellulose acetate than on uncoated cellulose acetate. These results suggest that atomic layer deposition is an appropriate method for improving the biological properties of hemostatic agents and other blood‐contacting biomaterials.
Miniaturized lensless imaging systems for cell and microorganism visualization in point‐of‐care testing
Authors: Gurkan Umut Atakan , Moon Sangjun , Geckil Hikmet , Xu Feng , Wang Shuqi , Lu Tian Jian , Demirci Utkan
Published: February 2011

Low‐cost, robust, and user‐friendly diagnostic capabilities at the point‐of‐care (POC) are critical for treating infectious diseases and preventing their spread in developing countries. Recent advances in micro‐ and nanoscale technologies have enabled the merger of optical and fluidic technologies (optofluidics) paving the way for cost‐effective lensless imaging and diagnosis for POC testing in resource‐limited settings. Applications of the emerging lensless imaging technologies include detecting and counting cells of interest, which allows rapid and affordable diagnostic decisions. This review presents the advances in lensless imaging and diagnostic systems, and their potential clinical applications in developing countries. The emerging technologies are reviewed from a POC perspective considering cost effectiveness, portability, sensitivity, throughput and ease of use for resource‐limited settings.
Synthesis, Receptor Binding, and CNS Pharmacological Studies of New Thyrotropin‐Releasing Hormone (TRH) Analogues
Authors: Monga Vikramdeep , Meena Chhuttan L. , Rajput Satyendra , Pawar Chandrashekhar , Sharma Shyam S. , Lu Xinping , Gershengorn Marvin C. , Jain Rahul
Published: February 2011

As part of our search for selective and CNS‐active thyrotropin‐releasing hormone (TRH) analogues, we synthesized a set of 44 new analogues in which His and pGlu residues were modified or replaced. The analogues were evaluated as agonists at TRH‐R1 and TRH‐R2 in cells in vitro, and in vivo in mice for analeptic and anticonvulsant activities. Several analogues bound to TRH‐R1 and TRH‐R2 with good to moderate affinities, and are full agonists at both receptor subtypes. Specifically, analogue 21 a (R=CH3) exhibited binding affinities (Ki values) of 0.17 μM for TRH‐R1 and 0.016 μM for TRH‐R2; it is 10‐fold less potent than TRH in binding to TRH‐R1 and equipotent with TRH in binding to TRH‐R2. Compound 21 a, the most selective agonist, activated TRH‐R2 with a potency (EC50 value) of 0.0021 μM, but activated TRH‐R1 at EC50=0.05 μM, and exhibited 24‐fold selectivity for TRH‐R2 over TRH‐R1. The newly synthesized TRH analogues were also evaluated in vivo to assess their potencies in antagonism of barbiturate‐induced sleeping time, and several analogues displayed potent analeptic activity. Specifically, analogues 21 a,b and 22 a,b decreased sleeping time by nearly 50 % more than TRH. These analogues also displayed potent anticonvulsant activity and provided significant protection against PTZ‐induced seizures, but failed to provide any protection in MES‐induced seizures at 10 μmol kg−1. The results of this study provide evidence that TRH analogues that show selectivity for TRH‐R2 over TRH‐R1 possess potent CNS activity.
Comparison of a Pair of Synthetic Tea‐Catechin‐Derived Epimers: Synthesis, Antifolate Activity, and Tyrosinase‐Mediated Activation in Melanoma
Authors: Sáez‐Ayala Magalí , Sánchez‐del‐Campo Luis , Montenegro María F. , Chazarra Soledad , Tárraga Alberto , Cabezas‐Herrera Juan , Rodríguez‐López José Neptuno
Published: February 2011

Despite bioavailability issues, tea catechins have emerged as promising chemopreventive agents because of their efficacy in various animal models. We synthesized two catechin‐derived compounds, 3‐O‐(3,4,5‐trimethoxybenzoyl)‐(−)‐catechin (TMCG) and 3‐O‐(3,4,5‐trimethoxybenzoyl)‐(−)‐epicatechin (TMECG), in an attempt to improve the stability and cellular absorption of tea polyphenols. The antiproliferative and pro‐apoptotic activities of both compounds were analyzed with various cancer cell systems, and TMCG, which was easily synthesized in excellent yield, was more active than TMECG in both melanoma and non‐melanoma cell lines. TMCG was also a better inhibitor of dihydrofolate reductase and was more efficiently oxidized by tyrosinase, potentially explaining the difference in activity between these epimers.
Aurones as Modulators of ABCG2 and ABCB1: Synthesis and Structure–Activity Relationships
Authors: Sim Hong May , Loh Ker Yun , Yeo Wee Kiang , Lee Chong Yew , Go Mei Lin
Published: February 2011

The ability of aurones to modulate the efflux activities of ABCG2 and ABCB1 was investigated by quantifying their effects on the accumulation of pheophorbide A (PhA) in ABCG2‐overexpressing MDA‐MB‐231/R cells and calcein AM in ABCB1‐overexpressing MDCKII/MDR1 cells. Key structural features for interactions at both ABCG2 and ABCB1 are a methoxylated ring A, an intact exocyclic double bond, and the location of the carbonyl bond on ring C. Modifications on rings B and C were less critical and served primarily to moderate activity and selectivity for one or both transporters. These SAR trends were quantified by Free–Wilson analyses and are reflected in a pharmacophore model for PhA accumulation. Several compounds were found to be equipotent with fumitremorgin C (FTC) in promoting PhA accumulation, and they also demonstrated strong affinities for ABCB1. These compounds were disubstituted on ring B with methoxy or a combination of methoxy and hydroxy groups. Taken together, our findings highlight the versatility of the aurone template as a lead scaffold for the design of dual‐targeting ABCG2 and ABCB1 modulators.
Continuous Synthesis of tert‐Butyl Peroxypivalate using a Single‐Channel Microreactor Equipped with Orifices as Emulsification Units
Authors: Illg Tobias , Hessel Volker , Löb Patrick , Schouten Jaap C.
Published: February 2011

The two‐step synthesis of tert‐butyl peroxypivalate is performed in a single‐channel microreactor. The first step, the deprotonation of tert‐butyl hydroperoxide, is done in a simple mixer tube setup. The residence time section for the second reaction step is equipped with orifices for interfacial area renewal, needed for ensuring mass transfer between the two immiscible phases. The strong dependence of the reaction performance on the size of the interfacial area is demonstrated by using a setup with 4 orifices (distance of 52 cm), giving a HPLC yield of 71 % at a residence time of 8 s and a reaction temperature of 23 °C. A further shortening of orifice distances helped to shorten the residence time down to 1.5 s and 0.5 s (using 9 orifices and 3 orifices with a distance of 5 cm). When using these setups, the produced heat could not be removed from the system sufficiently quickly (ΔT=38 K). The achieved yields (ca. 70 % by HPLC) are close to the state of the art (cascaded batch processing) and provide an indication that the tert‐butyl peroxypivalate synthesis can be performed at higher temperatures or at least, a more flexible process control can be allowed compared to high‐volume batch reactors. Processing at higher reaction temperatures up to 70 °C shows a slight optimum at reaction temperatures between 40 °C to 50 °C, depending on the setup used. Knowing this novel process window as well as the optimum orifice geometry and distance will allow for tailored design of the microreactor. For the processing in the single‐channel microreactor setup using 9 orifices (distance of 5 cm) and a reaction temperature of 40 °C a space‐time‐yield of 420 000 g L−1 h−1 was reached which is higher than the space‐time‐yield for the industrial 3 cascaded batch reactor process (190 g L−1 h−1).
Spin Crossover and Solvate Effects in 1D FeII Chain Compounds Containing Bis(dipyridylamine)‐Linked Triazine Ligands
Authors: Ross Tamsyn M. , Moubaraki Boujemaa , Turner David. R. , Halder Gregory J. , Chastanet Guillaume , Neville Suzanne M. , Cashion John D. , Létard Jean‐François , Batten Stuart R. , Murray Keith S.
Published: February 2011

A series of 1D polymeric FeII spin crossover (SCO) compounds of type trans‐[FeII(NCX)2(L)]·Solvent has been synthesised {L = DPPyT = 1‐[4,6‐bis(dipyridin‐2‐ylamino)‐1,3,5‐triazin‐2‐yl]pyridin‐4(1H)‐one for 1–4; NCX = NCS– for 1 and 2, NCSe– for 3 and 4; Solvent = 2.5CH2Cl2 for 1, 2CHCl3·0.5CH3OH for 2 and 4, CH2Cl2 for 3; L = DPT (6‐phenoxy‐N2,N2,N4,N4‐tetra‐2‐pyridinyl‐1,3,5‐triazine‐2,4‐diamine) for 5; NCX = NCS– for 5; Solvent = 2CH3OH·H2O for 5; L = DQT {4‐[4,6‐bis(dipyridin‐2‐ylamino)‐1,3,5‐triazin‐2‐yloxy]phenol} for 6–8; NCX– = NCS– for 6; Solvent = 2CH2Cl2 for 6; NCX– = NCSe– for 7; Solvent = CH2Cl2·CH2ClCH2Cl for 7; NCX– = NCSe– for 8; Solvent = 1.5CH2Cl2·0.5CH3OH for 8}. Two mononuclear complexes, trans‐[FeII(NCS)2(DPT)2]·2CH3OH (9) and trans‐[FeII(NCSe)2(DPT)2]·2CH3OH (10), contained the L ligand in a terminal bidentate coordination mode. As well as variations made in the NCX– ligands, variations were also made in substituent groups on the s‐triazine “core” of L to investigate their intermolecular/supramolecular role in crystal packing and, thus, their influence on SCO properties. All the complexes crystallised as solvates, and the influence of the latter on the magnetism and spin transitions was explored. A wide range of physical methods was employed, as a function of temperature, viz. crystallography, PXRD (synchrotron), susceptibilities, LIESST and Mössbauer effect, in order to probe magnetostructural correlations in these 1D families. New examples of half‐crossovers, with ordered –LS–HS–LS–HS– intrachain states existing below T1/2, have been observed and comparisons made to related one‐ or two‐step systems. All the observed transitions are gradual and non‐hysteretic, and brief comments are made in relation to recent theoretical models for cooperativity, developed elsewhere.
C–F Bond Activation of Highly Fluorinated Molecules at Rhodium: From Model Reactions to Catalysis (Eur. J. Inorg. Chem. 5/2011)
Authors: Braun Thomas , Wehmeier Falk
Published: February 2011

The cover picture shows C–F bond‐cleavage reactions at highly fluorinated substrates by rhodium complexes. The thermodynamic driving force is provided by the formation of strong element–fluorine bonds such as H–F, Si–F or B–F bonds. Details are presented in the Microreview by T. Braun and F. Wehmeier on p. 613 ff.
Enantioselective CuII‐Catalyzed Diels–Alder and Michael Addition Reactions in Water Using Bio‐Inspired Triazacyclophane‐Based Ligands
Authors: Bauke Albada H. , Rosati Fiora , Coquière David , Roelfes Gerard , Liskamp Rob M. J.
Published: February 2011

A triazacyclophane (TAC) scaffold decorated with three histidine amino acid residues was used as a tridentate ligand in asymmetric copper(II)‐catalysed Diels–Alder and Michael addition reactions in water. Enantiomeric excesses up to 55 % were obtained in Diels–Alder reactions using ligands in which the histidine residues were directly attached to the TAC scaffold. Additional amino acid residues on the N‐termini of the histidine residues or positioned between the histidine residues and the TAC scaffold, resulted in almost complete loss of enantioselectivity. Modelling studies of the coordination complex of the most specific ligand indicated the presence of a substrate binding pocket in proximity to the catalytically active centre.
Chemistry on a Half‐Shell: Synthesis and Derivatization of Buckybowls
Authors: Sygula Andrzej
Published: February 2011

Buckybowls, bowl‐shaped polycyclic aromatic hydrocarbons structurally related to fullerenes, represent a class of hydrocarbons with unique properties and a potential for application as novel materials. This review outlines the development of the practical preparations of buckybowls, starting with the original synthesis of corannulene achieved in 1966. A particular attention is paid to the last decade developments which include construction of large, highly nonplanar molecular networks (molecular clips and tweezers) capable of binding guest molecules of various sizes and shapes. In particular, such molecular clips were proven to form stable supramolecular complexes with fullerenes C60 and C70, both in solution and in the solid state.
A Computational (DFT, MP2) and GIAO NMR Study of Substituent Effects in Benzenediazonium Mono‐ and Dications
Authors: Borosky Gabriela L. , Okazaki Takao , Laali Kenneth K.
Published: February 2011

15N and 13C NMR chemical shifts were computed by GIAO‐DFT and GIAO‐MP2 for a series of p‐substituted benzenediazonium mono‐ and dications in order to probe the electronic effects of the substituents on the diazonium moiety. Optimized geometries and N/N vibrational frequencies werealso considered for comparison. The GIAO‐DFT derived15N chemical shifts correlate more closely with the experimental values as compared to GIAO‐MP2. Energyminimizations at the B3LYP/6‐311+G(2d,p), M062X‐6‐311+G(2d,p), MP2/6‐311+G(2d,p), G2(MP2), and CBS‐Q levels were carried out. Relative dication stability order HCO+ > HOMe+ > HN(Me)2+ > HOH+ > HCN+ > HNO2+ was derived from isodesmic proton transfer reactions. The Nβ‐protonated dications were less stable than the corresponding p‐R+ dications. Among the regioisomeric Nβ‐protonated dications (with R = –F, –Cl, and –CN), those with the R group in the para position were preferred. For the regioisomeric, ring‐protonated benzenium‐diazonium dications, the meta‐protonated dications were more favored (by DFT and MP2). Influence of the counterion and solvent on the computed 15N NMR chemical shifts in PhN2+ X– were also assessed.
Continuous‐time random walk models of DNA electrophoresis in a post array: Part I. Evaluation of existing models
Authors: Olson Daniel W. , Ou Jia , Tian Mingwei , Dorfman Kevin D.
Published: February 2011

Several continuous‐time random walk (CTRW) models exist to predict the dynamics of DNA in micropost arrays, but none of them quantitatively describes the separation seen in experiments or simulations. In Part I of this series, we examine the assumptions underlying these models by observing single molecules of λ DNA during electrophoresis in a regular, hexagonal array of oxidized silicon posts. Our analysis takes advantage of a combination of single‐molecule videomicroscopy and previous Brownian dynamics simulations. Using a custom‐tracking program, we automatically identify DNA‐post collisions and thus study a large ensemble of events. Our results show that the hold‐up time and the distance between collisions for consecutive collisions are uncorrelated. The distance between collisions is a random variable, but it can be smaller than the minimum value predicted by existing models of DNA transport in post arrays. The current CTRW models correctly predict the exponential decay in the probability density of the collision hold‐up times, but they fail to account for the influence of finite‐sized posts on short hold‐up times. The shortcomings of the existing models identified here motivate the development of a new CTRW approach, which is presented in Part II of this series.
A new tribe modified shuffled frog leaping algorithm for multi‐objective distribution feeder reconfiguration considering distributed generator units
Authors: Niknam Taher , Farsani Ehsan Azad , Nayeripour Majid , Bahmani Firouzi Bahman
Published: February 2011

In this paper, an efficient Tribe‐Modified Shuffled Frog Leaping Algorithm (T‐MSFLA) is presented to solve Multi‐objective Distribution Feeder Reconfiguration (MDFR) problem with regard to Distributed Generator (DG) units. The Distribution Feeder Reconfiguration (DFR) is one of the most important control schemes in the distribution networks, which can be affected by DG units. The main focus of this study is to minimize the real power loss, deviation of the nodes' voltage, and emission produced by DG units and distribution companies (substation buses), and total cost of the active power generated by DG units and distribution companies, so that radiality of the network is maintained. In this paper, the max–min method has been used to preserve the radiality of network. Because of the fact that the objectives are different and no commensurable, it is difficult to solve the problem by conventional approaches that may optimize a single objective problem. This paper presents a new T‐MSFLA algorithm for the MDFR problem. In the proposed algorithm (T‐MSFLA) at first we modify the frog leaping rule of shuffled frog leaping algorithm, the modified algorithm is MSFLA, and then a Tribe‐MSFLA is used to prevent the prematurity of MSFLA. We consider an external repository to save non‐dominated solutions found during the search process. Since the objective functions are not the same, a fuzzy clustering technique is used to control the size of the repository within the limits. The proposed algorithm is tested on three distribution test feeders. The results of simulation show that the proposed method is very powerful and guarantees to obtain the global optimization. Copyright © 2011 John Wiley & Sons, Ltd.
Study of an isolated wind–diesel hybrid power system with STATCOM by incorporating a new mathematical model of PMIG
Authors: Sharma Pawan , Bhatti T. S. , Ramakrishna K. S. S.
Published: February 2011

This paper presents automatic reactive power control of an isolated wind–diesel hybrid power system. A synchronous generator is used for power generation from diesel and a permanent‐magnet induction generator (PMIG) is used for electric power generation from wind turbine. A new mathematical model is developed to incorporate the effect of permanent‐magnet of the PMIG in the generation of reactive power. To eliminate the gap between reactive power generation and demand, a variable source of reactive power is used such as static synchronous compensator (STATCOM). A study on the wind–diesel system is conducted based on small signal analysis by considering IEEE type‐1 excitation system for the synchronous generator. The paper also shows the dynamic performance of the hybrid system both for constant and variable slip conditions and 1% step change in reactive power load. Copyright © 2011 John Wiley & Sons, Ltd.
The mean–WCVaR based model for LDC's optimal portfolio in multi‐energy markets
Authors: Liu Haoming , Hou Yunhe
Published: February 2011

In a competitive electricity market with highly fluctuated electricity price, local distribution companies (LDCs) need to purchase electric power from several energy markets, such as spot markets, long‐term tolling agreements and forward contracts, to maximize profits and minimize risks. Conditional Value‐at‐Risk (CVaR) can measure risk efficiently, but only one kind of price distribution rule may be considered. In fact, the spot electricity price usually does not follow the normal distribution, and it might be shown as logarithmic normal distribution if there was no enough supply at peak load situation. In this paper, a novel WCVaR method—Weighted Conditional Value‐at‐Risk—is proposed to measure the purchasing risk of LDC with multiple purchase options, especially when the electricity price follows more than one distribution rules. The Mean–WCVaR model is built as a mathematical programing problem to derive the efficient frontier that indicates the optimal tradeoffs available to LDC between expected revenue and purchasing risk in several energy markets. The existence of optimal solution of proposed WCVaR model is proved mathematically. Simulation results show the efficiency of the proposed model. The proposed model provides a new method for LDC to determine the optimal purchasing strategies considering the risk. Copyright © 2011 John Wiley & Sons, Ltd.
A new approach for load flow analysis of integrated AC–DC power systems using sequential modified Gauss–Seidel methods
Authors: Messalti Sabir , Belkhiat Saad , Saadate Shahrokh , Flieller Damien
Published: February 2011

The paper describes a new approach for the load flow calculations of integrated AC–DC system. A simple and reliable method for sequential modified Gauss and Gauss–Seidel power flow for AC–DC system is developed. This approach is based on applying nodal injection theory at all buses. The DC system is treated by the current injected to the buses where it is connected and its effect is reflected at internal buses by additional power injection. Iterations between AC and DC power flow algorithms are made to match boundary conditions between the two systems. In this approach, the active and reactive power and the AC voltages at the converter buses are considered as the interface between the AC and DC equations in each iteration step. The combined AC–DC equations are solved separately using sequential modified Gauss and Gauss–Seidel methods. The developed algorithm to solve the AC–DC power flow has been tested on the IEEE 9‐bus test system. Copyright © 2011 John Wiley & Sons, Ltd.
Effect of oral supplementation of Lactobacillus reuteri in reduction of intestinal absorption of aflatoxin B1 in rats
Authors: Hernandez‐Mendoza Adrián , González‐Córdova Aarón Fernando , Vallejo‐Cordoba Belinda , Garcia Hugo Sergio
Published: February 2011

The goals of this work were to assess the ability of Lactobacillus reuteri to bind aflatoxin B1 in the intestinal tract and determine its effect on intestinal absorption of the toxin dispensed in either single or multiple doses in a murine model. Male Wistar rats were used, and two experiments were conducted after bacteria were implanted. Experiment one involved a single‐oral dose of toxin, and the subsequent flow cytometric analysis of bacteria isolated from the small intestine and treated with specific FITC‐labeled AFB1 antibodies. The second experiment was carried out supplying the toxin in 7 oral sub‐doses, and the later quantification of AFB1‐Lys adducts in blood samples by ELISA assay. The results demonstrated that L. reuteri was able to bind AFB1 in the intestinal tract, mostly in the duodenum. Furthermore, the AFB1‐Lys adducts were present at significantly lower levels in those animals receiving AFB1 plus bacteria than in those receiving only AFB1. Our findings confirm that probiotic bacteria could act as biological barriers in normal intestinal conditions thereby reducing the bioavailability of AFB1 ingested orally in a single or multiple doses, thus avoiding its toxic effects. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The GAL genetic switch: visualisation of the interacting proteins by split‐EGFP bimolecular fluorescence complementation
Authors: Barnard Emma , Timson David J.
Published: February 2011

A split‐EGFP bimolecular fluorescence complementation assay was used to visualise and locate three interacting pairs of proteins from the GAL genetic switch of the budding yeast, Saccharomyces cerevisiae. Both the Gal4p‐Gal80p and Gal80p‐Gal3p pairs were found to be located in the nucleus under inducing conditions. However, the Gal80p‐Gal1p complex was located throughout the cell. These results support recent work establishing an initial interaction between Gal3p and Gal80p occurring in the nucleus. Labelling of all three protein pairs impaired the growth of the yeast strains and resulted in reduced galactokinase activity in cell extracts. The most likely cause of this impairment is decreased dissociation rates of the complexes, caused by the essentially irreversible reassembly of the EGFP fragments. This suggests that a fully functional GAL genetic switch requires dynamic interactions between the protein components. These results also highlight the need for caution in the interpretation of in vivo split‐EGFP experiments. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Isolation, characterization and identification of a Paracoccus sp. 2‐haloacid‐degrading bacterium from the marine sponge Hymeniacidon perlevis
Authors: Huang Jianyu , Xin Yanjuan , Zhang Wei
Published: February 2011

A 2‐haloacid dehalogenase‐producing bacterium, designated DEH99, was isolated from the marine sponge Hymeniacidon perlevis using a modified enrichment medium and a pH indicator method. DEH99 could degrade only half of the racemic mixture 2‐chloropropionic acid (2‐CPA) in the medium. The dehalogenase of DEH99 was further determined to be a (S)‐2‐haloacid dehalogenase, which can degrade 2‐CPA, 2‐bromopropionic acid (2‐BPA), and iodoacetic acid. The gene encoding the (S)‐2‐haloacid dehalogenase was partially sequenced and classified into the Group II family. The 2‐haloacid dehalogenase showed the highest sequence similarity (77% with 21% query coverage) to the haloacid dehalogenase (dhlB) gene of Xanthobacter autotrophicus. A phylogenetic analysis of the 16S rDNA sequence demonstrated that the isolate DEH99 is a member of the genus Paracoccus. To our knowledge, this is the first report detailing the isolation of a strain of genus Paracoccus having 2‐haloacid dehalogenase activity from marine sponges. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)