bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanistic features of the sonochemical degradation of organic pollutants
Authors: Sivasankar Thirugnanasambandam , Moholkar Vijayanand S.
Published: June 2008

This work considers the mechanistic features of sonochemical degradation of volatile (chlorobenzene) and nonvolatile (phenol) organic pollutants. The sonochemical degradation of pollutant occurs in two pathways: thermal pyrolysis and hydroxylation. By coupling experimental results to bubble dynamics model, we have tried to establish relative contribution of these pathways to degradation of two kinds of pollutants. It is revealed that degradation of volatile pollutants occurs primarily by thermal pyrolysis while hydroxylation is the predominant mechanism of degradation of nonvolatile pollutants. The simulation results also help explain some interesting trends observed in degradation with reaction parameters such as initial pollutant concentration and salt addition to solution. These parameters are found to influence both pathways of degradation that leads to enhancement in degradation. However, the extent of this influence on hydroxylation and pyrolysis pathways is different for phenol and chlorobenzene. This is attributed to different partitioning behavior and solubility of the two pollutants. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Determination of cubic equation of state parameters for pure fluids from first principle solvation calculations
Authors: Hsieh Chieh‐Ming , Lin Shiang‐Tai
Published: June 2008

A new method for estimation of parameters in cubic equations of state from ab initio solvation calculations is presented. In this method, the temperature‐dependent interaction parameter a(T) is determined from the attractive component of solvation free energy, whereas the volume parameter b is assumed to be that of solvation cavity. This method requires only element‐specific parameters, i.e., atomic radius and dispersion coefficient, and nine universal parameters for electrostatic and hydrogen‐bonding interactions. The equations of state (EOS) parameters so determined allow the description of the complete fluid phase diagram, including the critical point. We have examined this method using the Peng–Robinson EOS for 392 compounds and achieved an accuracy of 43% in vapor pressure, 17% in liquid density, 5.4% in critical temperature, 11% in critical pressure, and 4% in critical volume. This method is, in principle, applicable to any chemical species and is especially useful for those whose experimental data are not available. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Preparation of magnetic γ‐Al2O3 supported palladium catalyst for hydrogenation of nitrobenzene
Authors: Lang Yuqi , Wang Qiaoqiao , Xing Jianmin , Zhang Bo , Liu Huizhou
Published: June 2008

Spherical alumina support with magnetic core of 134 nm in diameter was prepared by the controlled hydrolysis of aluminums iso‐propoxide. The magnetite Fe3O4 nanoparticles were first synthesized by coprecipitation. Later silica film was coated onto the surface of Fe3O4 nano particles with the sodium silicate acidification method. Alumina was supported on Fe3O4/SiO2 film by the controlled hydrolysis of aluminum alkoxide in a dilute solution consisting of cyclohexane and 2‐propanol. Finally, magnetic alumina supported palladium catalysts were prepared by microemulsion method. The surface morphology and crystal structure of the magnetic alumina and catalysts were characterized by XRD, TEM, BET, and VSM, respectively. The results showed that these kinds of composite particle exhibit superparamagnetic behavior with zero coercivity and remanence. The catalysts show high activity for nitrobenzene directly hydrogenating to aniline under mild conditions. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Family‐based association study between NOS‐I and ‐IIA polymorphisms and autism spectrum disorders in Korean trios
Authors: Kim Hyo‐Won , Cho Soo‐Churl , Kim Jae‐Won , Cho In Hee , Kim Soon Ae , Park Mira , Cho Eun Jeong , Yoo Hee‐Jeong
Published: June 2008

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with a strong genetic component and environmental risk factors. Nitric oxide (NO), which is produced by nitric oxide synthase (NOS), may play a role in the development of ASD. We genotyped nine single nucleotide polymorphisms (SNPs) in the NOS‐I gene and nine SNPs in the NOS‐IIA gene and carried out the transmission disequilibrium test (TDT) and haplotype analysis in 151 Korean ASD trios. We found preferential transmission of the A allele of rs8068149 (P = 0.039) and G allele of rs1060826 (P = 0.035) of NOS‐IIA in ASD and the haplotype analysis revealed that the two haplotypes had significant associations (P = 0.014 and 0.031, respectively). The behavioral subdomain score of failure to use nonverbal behaviors to regulate social interaction in Autism Diagnostic Interview‐Revised (ADI‐R) was significantly higher in subjects with the GG or AG allele in rs1060826 of NOS‐IIA compared to those who had the AA allele (P = 0.027). These results provide significant but weak evidence for an association between NOS‐IIA and ASD in the Korean population. © 2008 Wiley‐Liss, Inc.
The impact of genetic variation in DRD2 and SLC6A3 on smoking cessation in a cohort of participants 1 year after enrollment in a lung cancer screening study
Authors: Styn Mindi A. , Nukui Tomoko , Romkes Marjorie , Perkins Kenneth , Land Stephanie R. , Weissfeld Joel L.
Published: June 2008

Smoking cessation strategies continue to have disappointing results. By determining the interindividual genetic differences that influence smoking behaviors, we may be able to develop tailored strategies that increase the likelihood of successful cessation. This study attempts to determine genetic influences on the relationship between the dopamine pathway and smoking cessation by examining associations with a variable number tandem repeat variation in SLC6A3 and the DRD2 variants TaqIA (A2 vs. A1), TaqIB (B2 vs. B1), C957T (C vs. T), and −141C Ins/Del (C vs. Del). Baseline smokers in the Pittsburgh Lung Screening Study who provided information on smoking status 1 year later were evaluated. We frequency‐matched those who were not abstinent at 1 year to those who were abstinent at 1 year by gender, decade of age, and time of enrollment (3‐month intervals) in a 3:1 ratio (N = 881). Logistic regression was used to identify the effect of genotype on abstinence at 1 year. In a model containing the matching variables and other genotypes, DRD2 TaqIA was significantly associated with being abstinent at 1 year (P = 0.01). Compared to participants who were homozygous for the TaqIA major allele (A2A2), participants who carried at least one minor allele (A1) were less likely to quit (Odds Ratio: 0.47, 95% CI: 0.24–0.94). The other dopamine receptor genotypes and the SLC6A3 genotype were not associated with smoking status at 1 year. The association between DRD2 TaqIA and smoking cessation supports the hypothesis that genetic variation in the dopamine pathway influences smoking cessation. © 2008 Wiley‐Liss, Inc.
Tensidfreie nichtwässrige Synthese von Metalloxid‐Nanostrukturen
Authors: Pinna Nicola , Niederberger Markus
Published: June 2008

Tensidfreie nichtwässrige (und/oder nichthydrolytische) Sol‐Gel‐Prozesse repräsentieren eine der vielfältigsten und leistungsfähigsten Synthesemethoden für hoch reine und homogene Metalloxid‐Nanokristalle. Obwohl die verwendeten Reaktionssysteme lediglich aus den Metalloxid‐Vorstufen und organischen Lösungsmitteln bestehen, können auf diesem Weg doch einheitliche Nanokristalle mit vielfältigen Größen und Formen erhalten werden. Durch die geringe Zahl an Ausgangskomponenten gelingt es mit einfachen Mitteln, die Bildungsmechanismen der Metalloxide zu studieren. Nichthydrolytische Wege zu anorganischen Nanomaterialien unter Einsatz von Tensiden wurden kürzlich bereits diskutiert. Der vorliegende Kurzaufsatz ergänzt dieses Thema durch die Behandlung von tensidfreien Prozessen, die mittlerweile eine nützliche Alternative zu Synthesen unter Tensidzusatz sowie zu klassischen Sol‐Gel‐Prozessen in wässrigen Medien darstellen.
Melt mixing of carbon fibers and carbon nanotubes incorporated polyurethanes
Authors: Abdullah Shahrul Azam , Iqbal Azhar , Frormann Lars
Published: June 2008

Polyurethane composites filled with carbon fibers (CF) and carbon nanotubes (CNT) were prepared by mixing and injection molding, and its mechanical as well as their thermal properties were investigated. Dynamic mechanical analysis (DMA), thermogravimetry analysis (TGA), and thermal conductivity tests were done, and the properties were evaluated as a function of the filler concentration. The storage modulus of the composites increased with fillers concentration, which also mean the increase of the stiffness, suggest a good adhesion between the polyurethane matrix and the fillers. Addition of more CF and CNT to the composites broadened and lowered the peak of tan δ specifies that the polyurethane composite became more elastic because there is a good adhesion between the fillers and the matrix. The addition of carbon fillers improves the thermal stability of the polyurethane. The inclusions of CNT show a better thermal stability when compared with CF. The addition of carbon fillers also increased the thermal conductivity of the polyurethane composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Dehydration of benzene through fluorine containing aromatic polyamide membrane by pervaporation
Authors: Gutch P. K. , Pandey L. K. , Saxena Chhaya
Published: June 2008

A series of soluble polyamides were synthesized by direct polycondensation of the 5‐tert‐butyl isophthalic acid with different diamines. Solution (20%) of the polymers in suitable solvents was used to cast the membranes. The membranes showed selectivity toward the benzene (Bz) in a mixture of Bz/water (H2O). Water affinity of the membrane was found to be lower than that of Bz. The polyamide incorporating hexafluoro isopropylidene moiety was promising for the dehydaration of Bz and breaking of Bz/H2O azeotrope. The polymers exhibited inherent viscosities, ranging from 0.40 to 0.92 dL/g and 10% weight loss in synthetic air up to 474°C. Glass transition temperature measured by DSC and DMA reached up to 258°C. The membranes were pale yellow in appearance having tensile strength up to 85 MPa, modulus of elasticity up to 2.6 GPa, and elongation at break up to 9.5%, depending upon the exact repeating unit structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Tin‐coupled star‐shaped block copolymer of styrene and butadiene (I) synthesis and characterization
Authors: Feng Huadong , Zhang Xingying , Zhao Suhe
Published: June 2008

A new kind of star‐shaped block copolymer: tin‐coupled polybutadiene‐b‐ploy(styrene‐butadiene) ((SB‐B)4Sn) was synthesized by two‐stage anionic polymerization technology. A novel multifunctional organo‐lithium was used as initiator, and two different types of copolymers were formed, namely, S‐PB‐PSB and S‐PB‐PSB‐PS, depending on the styrene content in loading solution (St%). In copolymerization, the homo‐polybutadiene block was formed in the first reaction stage, and the residual blocks were formed in the second stage with the presence of tetrahydrofuran (THF). S‐PB‐PSB was synthesized when the St% was lower than 34.9%, otherwise S‐PB‐PSB‐PS was generated. Nuclear magnetic resonance (NMR) results showed that the amount of vinyl based upon the butadiene content within poly(butadiene‐styrene) blocks decreased dramatically as the St% was increased. Dynamic mechanical thermal analyzer (DMTA) spectra showed broadened loss peak as the St% was increased. Transmission electron microscopy (TEM) was employed to characterize the copolymer morphology, and the results showed different phase‐separated morphologies as St% increased. Mechanical property testing results indicated that these two copolymers met the requirements of high performance tire tread. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Building ontological relationships: A new approach
Authors: Kayed Ahmad , Hirzallah Nael , Shalabi Luai A. Al , Najjar Mohannad
Published: June 2008

Ontology plays an essential role in recognizing the meaning of the information in Web documents. It has been shown that extracting concepts is easier than building relationships among them. For a defined set of concepts, many existing algorithms produce all possible relationships for that set. This makes the process of refining the relationships almost impossible. A new algorithm is needed to reduce the number of relationships among a defined set of concepts produced by existing algorithms. This article contributes such an algorithm, which enables a domain‐knowledge expert to refine the relationships linking a set of concepts. In the research reported here, text‐mining tools have been used to extract concepts in the domain of e‐commerce laws. A new algorithm has been proposed to reduce the number of extracted relationships. It groups the concepts according to the number of relationships with other concepts and provides formalization. An experiment and software have been built, proving that reducing the number of relationships will reduce the efforts needed from a human expert.
Next generation of information infrastructure: A comparative case study of Korea versus the United States of America
Authors: Shin Dong‐Hee
Published: June 2008

This study compares the United States of America and Korea's cases of national information infrastructure (NII) development, focusing on the role of the governments in the development of their NIIs and on the realization of the next generation of information infrastructure vision. The important similarities and differences can be seen by comparison on sociotechnical dimensions: government function, histories, visions, policy design, implementation plans, and realities and prospects. Findings show different patterns of NII development, providing insights for the next generation of NIIs. This study provides a prospect towards future information infrastructure needs in the context of dynamic sociotechnical changes.
Conference proceedings as a source of scientific information: A bibliometric analysis
Authors: Lisée Cynthia , Larivière Vincent , Archambault Éric
Published: June 2008

While several authors have argued that conference proceedings are an important source of scientific knowledge, the extent of their importance has not been measured in a systematic manner. This article examines the scientific impact and aging of conference proceedings compared to those of scientific literature in general. It shows that the relative importance of proceedings is diminishing over time and currently represents only 1.7% of references made in the natural sciences and engineering, and 2.5% in the social sciences and humanities. Although the scientific impact of proceedings is losing ground to other types of scientific literature in nearly all fields, it has grown from 8% of the references in engineering papers in the early 1980s to its current 10%. Proceedings play a particularly important role in computer sciences, where they account for close to 20% of the references. This article also shows that not unexpectedly, proceedings age faster than cited scientific literature in general. The evidence thus shows that proceedings have a relatively limited scientific impact, on average representing only about 2% of total citations, that their relative importance is shrinking, and that they become obsolete faster than the scientific literature in general.
Synthesis of 5‐Substituted 1H‐Tetrazoles by the Copper‐Catalyzed [3+2] Cycloaddition of Nitriles and Trimethylsilyl Azide
Authors: Jin Tienan , Kitahara Fukuzou , Kamijo Shin , Yamamoto Yoshinori
Published: June 2008

The copper‐catalyzed [3+2] cycloaddition between various nitriles and trimethylsilyl azide in DMF/MeOH produced the corresponding 5‐substituted 1H‐tetrazoles in good to high yields. It was proposed that the reaction proceeds through the formation in situ of a copper azide species and subsequent [3+2] cycloaddition with the nitriles. Furthermore, we found that a copper and triethylamine combined catalyst also promoted the cycloaddition of nitriles and trimethylsilyl azide to afford the 5‐substituted 1H‐tetrazoles at relatively low reaction temperatures. The copper azide species would be formed by reaction of the copper catalyst with Et3N⋅HN3 generated in situ.
Eastern Antarctic Peninsula precipitation delivery mechanisms: process studies and back trajectory evaluation
Authors: Russell Andrew , McGregor Glenn R. , Marshall Gareth J.
Published: June 2008

The atmospheric circulation patterns that result in precipitation events at a site on the eastern Antarctic Peninsula (AP) are investigated using back trajectories (BTs) driven by ERA‐40 data. Moisture delivery occurs from the east and west depending on the location of blocking events in the South Atlantic and Pacific Oceans. Observations are sparse in this region, so our process studies compare the trajectories (and the ERA‐40 fields from which they were derived) with advanced very high resolution radiometer (AVHRR) satellite images. It is found that the trajectories represent these transport mechanisms very well and that they are relatively insensitive to the initial trajectory elevation. Copyright © 2008 Royal Meteorological Society
Ruin theory for classical risk process that is perturbed by diffusion with risky investments
Authors: Lin Xiang
Published: June 2008

In this paper, we study the ruin theory for classical risk process that is perturbed by diffusion with risky investments. We obtain the upper bound for the minimal ruin probability. We also investigate the relationships between the adjustment coefficient and the diffusion volatility parameter, the risk‐free rate and the correlation coefficient by numerical calculation. We give the relationships between ruin and investment. Copyright © 2008 John Wiley & Sons, Ltd.
Prolonged weakening of the geomagnetic field (GMF) affects the immune system of rats
Authors: Roman Adam , Tombarkiewicz Barbara
Published: June 2008

The aim of this study was to find out how a long‐term shielding of the geomagnetic field (GMF) affected the immune system of rats. Male and female Wistar rats were kept up to an age of 2 months in a natural GMF (about 37 µT). Afterwards, the rats were divided into four groups (males and females separately): control rats were maintained in ambient GMF, while experimental animals were housed under conditions of a weakened GMF (below 12 µT) achieved with steel cages. After 6 months, the rats were sacrificed by decapitation. Spleens and thymuses were isolated and weighed. Peritoneal cells were eluted and cultured in vitro to study their ability to produce nitric oxide (NO) and to synthesize superoxide anion (O−2), important microbicidal molecules of macrophages. The number of macrophages was estimated by a crystal violet staining method. We found that the long‐term shielding of the GMF could influence the functioning of the immune system in a sex‐dependent manner. The deprivation of the GMF delayed physiological thymus involution, that effect being more strongly expressed in females. The weakening of the GMF resulted in an increased number of peritoneal macrophages, especially in males. The shielding of the GMF diminished the ability of macrophages to release NO and to synthesize O−2, those effects being more powerfully expressed in males and females, respectively. It is proposed that the observed changes in the immune system occur as a consequence of the protective effect of GMF shielding on the circadian rhythm‐dependent level of melatonin. Bioelectromagnetics 30:21–28, 2009. © 2008 Wiley‐Liss, Inc.
Rational improvement of simvastatin synthase solubility in Escherichia coli leads to higher whole‐cell biocatalytic activity
Authors: Xie Xinkai , Pashkov Inna , Gao Xue , Guerrero Jennifer L. , Yeates Todd O. , Tang Yi
Published: June 2008

Simvastatin is the active pharmaceutical ingredient of the blockbuster cholesterol lowering drug Zocor. We have previously developed an Escherichia coli based whole‐cell biocatalytic platform towards the synthesis of simvastatin sodium salt (SS) starting from the precursor monacolin J sodium salt (MJSS). The centerpiece of the biocatalytic approach is the simvastatin synthase LovD, which is highly prone to misfolding and aggregation when overexpressed from E. coli. Increasing the solubility of LovD without decreasing its catalytic activity can therefore elevate the performance of the whole‐cell biocatalyst. Using a combination of homology structural prediction and site‐directed mutagenesis, we identified two cysteine residues in LovD that are responsible for nonspecific intermolecular crosslinking, which leads to oligomer formation and protein aggregation. Replacement of Cys40 and Cys60 with alanine residues resulted in marked gain in both protein solubility and whole‐cell biocatalytic activities. Further mutagenesis experiments converting these two residues to small or polar natural amino acids showed that C40A and C60N are the most beneficial, affording 27% and 26% increase in whole cell activities, respectively. The double mutant C40A/C60N combines the individual improvements and displayed ∼50% increase in protein solubility and whole‐cell activity. Optimized fed‐batch high‐cell‐density fermentation of the double mutant in an E. coli strain engineered for simvastatin production quantitatively (>99%) converted 45 mM MJSS to SS within 18 h, which represents a significant improvement over the performance of wild‐type LovD under identical conditions. The high efficiency of the improved whole‐cell platform renders the biocatalytic synthesis of SS an attractive substitute over the existing semisynthetic routes. Biotechnol. Bioeng. 2009;102: 20–28. © 2008 Wiley Periodicals, Inc.
Evaluation of a critical process parameter: Oxygen limitation during cultivation has a fully reversible effect on gene expression of Bordetella pertussis
Authors: Streefland Mathieu , van de Waterbeemd Bas , Kint Joeri , van der Pol Leo A. , Beuvery E. Coen , Tramper Johannes , Martens Dirk E.
Published: June 2008

Modern (bio)pharmaceutical process development requires thorough investigation of all process parameters that are critical to product quality. The impact of a disturbance of such a parameter during processing needs to be known so that a rational decision can be made about the release of the product. In cultivation processes the dissolved oxygen (DO) concentration is generally accepted as being a critical parameter. In this article the impact of a 90 min period of oxygen limitation during the cultivation of the strictly aerobic Bordetella pertussis bacterium is investigated. The cultivation is the most important process step for the manufacturing of a vaccine against whooping cough disease. Samples were taken immediately before and after oxygen limitation and at the end of cultivation of four oxygen limited and three control cultivations. DNA microarray analysis of the full transcriptome of the B. pertussis bacterium revealed that a 90 min period of oxygen limitation has a substantial effect on overall gene expression patterns. In total 104 genes were identified as a significant hit at any of the sample points, of which 58 were directly related to oxygen limitation. The other genes were mainly affected towards the end of cultivation. Of all genes involved in oxygen limitation none were identified to show a significant difference between the oxygen limited and control cultivations at the end of the batch. This indicates a fully reversible effect of oxygen limitation on gene expression. This finding has implications for the risk assessment of dissolved oxygen concentration as a critical process parameter. Biotechnol. Bioeng. 2009;102: 161–167. © 2008 Wiley Periodicals, Inc.
Twenty‐four well plate miniature bioreactor system as a scale‐down model for cell culture process development
Authors: Chen Aaron , Chitta Rajesh , Chang David , Amanullah Ashraf
Published: June 2008

Increasing the throughput and efficiency of cell culture process development has become increasingly important to rapidly screen and optimize cell culture media and process parameters. This study describes the application of a miniaturized bioreactor system as a scaled‐down model for cell culture process development using a CHO cell line expressing a recombinant protein. The microbioreactor system (M24) provides non‐invasive online monitoring and control capability for process parameters such as pH, dissolved oxygen (DO), and temperature at the individual well level. A systematic evaluation of the M24 for cell culture process applications was successfully completed. Several challenges were initially identified. These included uneven gas distribution in the wells due to system design and lot to lot variability, foaming issues caused by sparging required for active DO control, and pH control limitation under conditions of minimal dissolved CO2. A high degree of variability was found which was addressed by changes in the system design. The foaming issue was resolved by addition of anti‐foam, reduction of sparge rate, and elimination of DO control. The pH control limitation was overcome by a single manual liquid base addition. Intra‐well reproducibility, as indicated by measurements of process parameters, cell growth, metabolite profiles, protein titer, protein quality, and scale‐equivalency between the M24 and 2 L bioreactor cultures were very good. This evaluation has shown feasibility of utilizing the M24 as a scale‐down tool for cell culture application development under industrially relevant process conditions. Biotechnol. Bioeng. 2009;102: 148–160. © 2008 Wiley Periodicals, Inc.
Anaerobic mineralization of pentachlorophenol (PCP) by combining PCP‐dechlorinating and phenol‐degrading cultures
Authors: Yang Suyin , Shibata Atsushi , Yoshida Naoko , Katayama Arata
Published: June 2008

The dechlorination and mineralization of pentachlorophenol (PCP) was investigated by simultaneously or sequentially combining two different anaerobic microbial populations, a PCP‐dechlorinating culture capable of the reductive dechlorination of PCP to phenol and phenol‐ degrading cultures able to mineralize phenol under sulfate‐ or iron‐reducing conditions. In the simultaneously combined mixture, PCP (about 35 µM) was mostly dechlorinated to phenol after incubation for 17 days under sulfate‐reducing conditions or for 22 days under iron‐reducing conditions. Thereafter, the complete removal of phenol occurred within 40 days under both conditions. In the sequentially combined mixture, most of the phenol, the end product of PCP dechlorination, was degraded within 12 days of inoculation with the phenol degrader, without a lag phase, under both sulfate‐ and iron‐reducing conditions. In a radioactivity experiment, [14C–U]–PCP was mineralized to 14CO2 and 14CH4 by the combined anaerobic microbial activities. Analysis of electron donor and acceptor utilization and of the production and consumption of H2, CO2, and CH4 suggested that the dechlorinating and degrading microorganisms compete with other microorganisms to perform PCP dechlorination and part of the phenol degradation in complex anoxic environments in the presence of electron donors and acceptors. The presence of a small amount of autoclaved soil slurry in the medium was possibly another advantageous factor in the successful dechlorination and mineralization of PCP by the combined mixtures. This anaerobic–anaerobic combination technology holds great promise as a cost‐effective strategy for complete PCP bioremediation in situ. Biotechnol. Bioeng. 2009;102: 81–90. © 2008 Wiley Periodicals, Inc.
Microalgae for oil: Strain selection, induction of lipid synthesis and outdoor mass cultivation in a low‐cost photobioreactor
Authors: Rodolfi Liliana , Chini Zittelli Graziella , Bassi Niccolò , Padovani Giulia , Biondi Natascia , Bonini Gimena , Tredici Mario R.
Published: June 2008

Thirty microalgal strains were screened in the laboratory for their biomass productivity and lipid content. Four strains (two marine and two freshwater), selected because robust, highly productive and with a relatively high lipid content, were cultivated under nitrogen deprivation in 0.6‐L bubbled tubes. Only the two marine microalgae accumulated lipid under such conditions. One of them, the eustigmatophyte Nannochloropsis sp. F&M‐M24, which attained 60% lipid content after nitrogen starvation, was grown in a 20‐L Flat Alveolar Panel photobioreactor to study the influence of irradiance and nutrient (nitrogen or phosphorus) deprivation on fatty acid accumulation. Fatty acid content increased with high irradiances (up to 32.5% of dry biomass) and following both nitrogen and phosphorus deprivation (up to about 50%). To evaluate its lipid production potential under natural sunlight, the strain was grown outdoors in 110‐L Green Wall Panel photobioreactors under nutrient sufficient and deficient conditions. Lipid productivity increased from 117 mg/L/day in nutrient sufficient media (with an average biomass productivity of 0.36 g/L/day and 32% lipid content) to 204 mg/L/day (with an average biomass productivity of 0.30 g/L/day and more than 60% final lipid content) in nitrogen deprived media. In a two‐phase cultivation process (a nutrient sufficient phase to produce the inoculum followed by a nitrogen deprived phase to boost lipid synthesis) the oil production potential could be projected to be more than 90 kg per hectare per day. This is the first report of an increase of both lipid content and areal lipid productivity attained through nutrient deprivation in an outdoor algal culture. The experiments showed that this marine eustigmatophyte has the potential for an annual production of 20 tons of lipid per hectare in the Mediterranean climate and of more than 30 tons of lipid per hectare in sunny tropical areas. Biotechnol. Bioeng. 2009;102: 100–112. © 2008 Wiley Periodicals, Inc.
Characterization of materials eliciting foreign body reaction in stapled human gastrointestinal anastomoses
Authors: Lim C B B , Goldin R D , Darzi A , Hanna G B
Published: June 2008

Background

Staples are made of titanium, which elicits minimal tissue reaction. The authors have encountered foreign body reaction associated with stapled human gastrointestinal anastomoses, although the literature has no reports of this. The aim of this study was to identify the refractile foreign materials causing this reaction.

Methods

Histological sections were taken from 14 gastrointestinal specimens from patients with a history of a stapled anastomosis within the specimen excised. These were reviewed by light and polarization microscopy. Scanning electron microscopy and energy dispersive X-ray analysis were carried out on these sections, staples and stapler cartridges used for gastrointestinal surgery.

Results

Foreign bodies rich in fluorine were found in three patients, and those rich in carbon in 12. Other elements identified included oxygen, calcium, sodium, potassium, magnesium, aluminium and silicon. One specimen was found to contain titanium with no surrounding foreign body reaction. Stapler cartridges contained carbon, oxygen, fluorine, calcium, sodium, potassium, magnesium, aluminium, silicon and traces of titanium. Staples were composed of pure titanium with some fibrous material on the surface containing elements found in stapler cartridges.

Conclusion

The presence of foreign body reaction was confirmed in stapled human gastrointestinal anastomoses. The source of refractile materials eliciting this reaction was the stapler cartridges.
Rho-kinase signalling mediates endotoxin hypersensitivity after partial hepatectomy
Authors: Slotta J E , Laschke M W , Menger M D , Thorlacius H
Published: June 2008

Background

Excessive loss of functional liver mass results in hepatic dysfunction and is associated with an increased sensitivity to infection. This experimental study investigated the role of Rho-kinase in hepatectomy-induced sensitization to endotoxin.

Methods

Male C57BL/6J mice underwent 68 per cent hepatectomy and were injected 24 h later with 100 µg Escherichia coli lipopolysaccharide (LPS). Simultaneously, animals received either fasudil or Y-27632 for Rho-kinase inhibition, or phosphate-buffered saline. Untreated hepatectomized animals served as positive controls and sham-operated animals as negative controls. Liver injury and inflammatory parameters were assessed 6 h after LPS challenge by serum alanine aminotransferase (ALT) levels, histomorphology and enzyme-linked immunosorbent assay.

Results

Hepatectomy resulted in a significant susceptibility to LPS, as indicated by inflammatory leucocyte recruitment (mean(s.e.m.) 10(1) leucocytes per high-power field), hepatocellular disintegration (ALT 22·4(3·1) µkat/l) and apoptotic cell death (3·8(0·2) per cent). Rho-kinase inhibition reduced leucocytic infiltration by more than 33 per cent, abolished hepatocellular apoptosis entirely, and reduced tumour necrosis factor α expression by more than 48 per cent and CXC chemokine expression by more than 36 per cent.

Conclusion

Hepatectomy increased susceptibility to LPS by Rho-kinase-dependent mechanisms. Blocking Rho-kinase signalling decreased LPS-induced liver injury in hepatectomized mice.
Urinary dysfunction after rectal cancer treatment is mainly caused by surgery
Authors: Lange M M , Maas C P , Marijnen C A M , Wiggers T , Rutten H J , Kranenbarg E Klein , van de Velde C J H
Published: June 2008

Background

Urinary dysfunction (UD) is common after rectal cancer treatment, but the contribution of each treatment component (surgery and radiotherapy) to its development remains unclear. This study aimed to evaluate UD during 5 years after total mesorectal excision (TME) and to investigate the influence of preoperative radiotherapy (PRT) and surgical factors.

Methods

Patients with operable rectal cancer were randomized to TME with or without PRT. Questionnaires concerning UD were completed by 785 patients before and at several time points after surgery. Possible risk factors, including PRT, demographics, tumour location, and type and extent of resection, were investigated by multivariable regression analysis.

Results

Long-term incontinence was reported by 38·1 per cent of patients, of whom 72·0 per cent had normal preoperative function. Preoperative incontinence (relative risk (RR) 2·75, P = 0·001) and female sex (RR 2·77, P < 0·001) were independent risk factors. Long-term difficulty in bladder emptying was reported by 30·6 per cent of patients, of whom 65·0 per cent had normal preoperative function. Preoperative difficulty in bladder emptying (RR 2·94, P < 0·001), peroperative blood loss (RR 1·73, P = 0·028) and autonomic nerve damage (RR 2·82, P = 0·024) were independent risk factors. PRT was not associated with UD.

Conclusion

UD is a significant clinical problem after rectal cancer treatment and is not related to PRT, but rather to surgical nerve damage.
Intermittent Pringle manoeuvre is not associated with adverse long-term prognosis after resection for colorectal liver metastases
Authors: Wong K H V , Hamady Z Z R , Malik H Z , Prasad R , Lodge J P A , Toogood G J
Published: June 2008

Background

Intermittent clamping of the porta hepatis, or the intermittent Pringle manoeuvre (IPM), is often used to control inflow during parenchymal liver transection. The aim of this study was to determine whether IPM is associated with an adverse long-term outcome after liver resection for colorectal liver metastasis (CRLM).

Methods

All patients undergoing resection for CRLM in 1993–2006, for whom data on IPM were recorded, were included in the study. A total of 563 patients was available for analysis.

Results

IPM was performed in 289 (51·3 per cent) of the patients. The duration of IPM ranged from 2 to 104 (median 22) min. There were no differences in clinicopathological features or postoperative morbidity between patients who had an IPM and those who did not. The median survival of patients undergoing IPM was 55·7 months compared with 48·9 months in those not having an IPM (P = 0·406). There was no difference in median disease-free survival between the two groups (22·1 versus 19·9 months respectively; P = 0·199).

Conclusion

IPM is not associated with an adverse long-term prognosis in patients undergoing liver resection for CRLM.
Survival benefit in a randomized clinical trial of faecal occult blood screening for colorectal cancer
Authors: Lindholm E , Brevinge H , Haglind E
Published: June 2008

Background

Early detection of colorectal cancer could reduce cancer-specific mortality. The aim of this trial was to evaluate the effect of faecal occult blood test (FOBT) screening on colorectal cancer mortality in a Swedish population.

Methods

All 68 308 citizens in Göteborg born between 1918 and 1931 were randomized to a screening or a control group at the age of 60–64 years. All were screened two to three times with rehydrated Hemoccult-II®. Compliance was 70·0 per cent (23 916 individuals). Those with a positive test result were offered sigmoidoscopy and a double-contrast enema. The primary endpoint was death from colorectal cancer.

Results

After a mean of 9 years from the last screening, there was a significant reduction in colorectal cancer mortality in the screening group compared with the control group. The overall risk ratio of death from colorectal cancer was 0·84 (95 per cent confidence interval 0·71 to 0·99). The groups did not differ in incidence of colorectal cancer or in overall mortality.

Conclusion

FOBT screening significantly reduces colorectal cancer mortality.
Reactivity of Molecular Dioxygen towards a Series of Isostructural Dichloroiron(III) Complexes with Tripodal Tetraamine Ligands: General Access to μ‐Oxodiiron(III) Complexes and Effect of α‐Fluorination on the Reaction Kinetics
Authors: Thallaj Nasser K. , Rotthaus Olaf , Benhamou Leila , Humbert Nicolas , Elhabiri Mourad , Lachkar Mohammed , Welter Richard , Albrecht‐Gary Anne‐Marie , Mandon Dominique
Published: June 2008

We have synthesized the mono, di‐, and tri‐α‐fluoro ligands in the tris(2‐pyridylmethyl)amine (TPA) series, namely, FTPA, F2TPA and F3TPA, respectively. Fluorination at the α‐position of these nitrogen‐containing tripods shifts the oxidation potential of the ligand by 45–70 mV per added fluorine atom. The crystal structures of the dichloroiron(II) complexes with FTPA and F2TPA reveal that the iron center lies in a distorted octahedral geometry comparable to that already found in TPAFeCl2. All spectroscopic data indicate that the geometry is retained in solution. These three isostructural complexes all react with molecular dioxygen to yield stable μ‐oxodiiron(III) complexes. Crystal structure analyses are reported for each of these three μ‐oxo compounds. With TPA, a symmetrical structure is obtained for a dicationic compound with the tripod coordinated in the κ4N coordination mode. With FTPA, the compound is a neutral μ‐oxodiiron(III) complex with a κ3N coordination mode of the ligand. Oxygenation of the F2TPA complex gave a neutral unsymmetrical compound, the structure of which is reminiscent of that already found with the trifluorinated ligand. On reduction, all μ‐oxodiiron(III) complexes revert to the starting iron(II) species. The oxygenation reaction parallels the well‐known formation of μ‐oxo derivatives from dioxygen in the chemistry of porphyrins reported almost three decades ago. The striking feature of the series of iron(II) precursors is the effect of the ligand on the kinetics of oxygenation of the complexes. Whereas the parent complex undergoes 90 % conversion over 40 h, the monofluorinated ligand provides a complex that has fully reacted after 30 h, whereas the reaction time for the complex with the difluorinated ligand is only 10 h. Analysis of the spectroscopic data reveals that formation of the μ‐oxo complexes proceeds in two distinct reversible kinetic steps with k1≈10 k2. For TPAFeCl2 and FTPAFeCl2 only small variations in the k1 and k2 values are observed. By contrast, F2TPAFeCl2 exhibits k1 and k2 values that are ten times higher. These differences in kinetics are interpreted in the light of structural and electronic effects, especially the Lewis acidity at the metal center. Our results suggest coordination of dioxygen as an initial step in the process leading to formation of μ‐oxodiiron(III) compounds, by contrast with an unlikely outer‐sphere reduction of dioxygen, which generally occurs at negative potentials.
A Materials Approach to Site‐Isolation of Grubbs Catalysts from Incompatible Solvents and m‐Chloroperoxybenzoic Acid
Authors: Mwangi Martin T. , Runge M. Brett , Hoak Kevin M. , Schulz Michael D. , Bowden Ned B.
Published: June 2008

The development of a method for site‐isolation of Grubbs second‐generation catalyst from MCPBA is described. In these reactions, Grubbs catalyst was dissolved in a solvent consisting of a mixture (1:1 v/v) of 1‐butyl‐3‐methylimidazolium hexafluorophosphate and methylene chloride and completely encapsulated within a thimble fabricated from polydimethylsiloxane (PDMS). A series of molecules that react by cross metathesis or ring‐closing metathesis were added to the interior of the thimble and allowed to react. In the last step, m‐chloroperoxybenzoic acid (MCPBA) dissolved in MeOH/H2O (1:1 v/v) was added to the exterior of the PDMS thimble. Small organic molecules diffused through the PDMS to react with MCPBA to form epoxides, but the Grubbs catalyst remained encapsulated. This result is important because Grubbs catalyst catalytically decomposes MCPBA at ratios of MCPBA to Grubbs of 3000 to 1. The yields for this two‐step cascade sequence ranged from 67 to 83 %. The concept behind this sequence is that small organic molecules have high flux through PDMS but large molecules—such as Grubbs catalyst—and ionic reagents—such as MCPBA—have much lower flux through PDMS. Small molecules can thus react both outside and inside PDMS thimbles, whereas incompatible catalysts and reagents remain site‐isolated from each other. This method does not require alteration of structures of the catalysts or reagents, so it may be applied to a wide range of homogeneous catalysts and reagents. To demonstrate further that the catalyst was encapsulated, the Grubbs catalyst was successfully recycled within the cascade sequence.
Thermal Isomerization of (+)‐cis‐ and (−)‐trans‐Pinane Leading to (−)‐β‐Citronellene and (+)‐Isocitronellene
Authors: Stolle Achim , Ondruschka Bernd , Bonrath Werner , Netscher Thomas , Findeisen Matthias , Hoffmann Markus M.
Published: June 2008

Catalyzed and uncatalyzed rearrangement reactions of terpenoids play a major role in laboratory and industrial‐scale synthesis of fine chemicals. Herein, we present our results on the thermally induced isomerization of pinane (1). Investigation of the thermal behavior of (+)‐cis‐ (1 a) and (−)‐trans‐pinane (1 b) in a flow‐type reactor reveals significant differences in both reactivity and selectivity concerning the formation of (−)‐β‐citronellene (2) and (+)‐isocitronellene (3) as main products. Possible explanations for these results are discussed on the basis of reaction mechanism and ground‐state geometries for 1 a and 1 b. To identify side reactions caused from ene cyclizations of 2 and 3, additional pyrolysis experiments were conducted that enabled the identification of almost all compounds in the network of C10H18‐hydrocarbon products formed from 1.
Discovery of New Biocatalysts for the Glycosylation of Terpenoid Scaffolds
Authors: Caputi Lorenzo , Lim Eng‐Kiat , Bowles Dianna J.
Published: June 2008

The synthesis of terpenoid glycosides typically uses a chemical strategy since few biocatalysts have been identified that recognise these scaffolds. In this study, a platform of 107 recombinant glycosyltransferases (GTs), comprising the multigene family of small molecule GTs of Arabidopsis thaliana have been screened against a range of model terpenoid acceptors to identify those enzymes with high activity. Twenty‐seven GTs are shown to glycosylate a diversity of mono‐, sesqui‐ and diterpenes, such as geraniol, perillyl alcohol, artemisinic acid and retinoic acid. Certain enzymes showing substantial sequence similarity recognise terpenoids containing a primary alcohol, irrespective of the linear or cyclical structure of the scaffold; other GTs glycosylate scaffolds containing secondary and tertiary alcohols; the carboxyl group of other terpenoids also represents a feature that is recognized by GTs previously known to form glucose esters with many different compounds. These data underpin the rapid prediction of potential biocatalysts from GT sequence information. To explore the potential of GTs as biocatalysts, their use for the production of terpenoid glycosides was investigated by using a microbial‐based whole‐cell biotransformation system capable of regenerating the cofactor, UDP‐glucose. A high cell density fermentation system was shown to produce several hundred milligrams of a model terpenoid, geranyl‐glucoside. The activities of the GTs are discussed in relation to their substrate recognition and their utility in biotransformations as a complement or alternative to chemical synthesis.
A Shift in Retrosynthetic Paradigm
Authors: Marek Ilan
Published: June 2008

The current state‐of‐the‐art synthesis for the formation of enantiomerically enriched all‐carbon quaternary stereocenters in acyclic system relies on the formation of a single carboncarbon bond per chemical step by asymmetric catalysis. These extraordinary sophisticated methods were logically classified among the most powerful and innovative ones. In this concept article, we are proposing a new retrosynthetic paradigm to solve differently such challenging problems. These new synthetic pathways lead to the diastereo‐ and enantiomerically pure formation of three new carboncarbon bonds in acyclic system, in a one‐pot reaction, including the formation of all‐carbon quaternary stereocenters by using classical reagents and experimental conditions and from common starting materials.
Toxicity Assessment of Industrial Effluent by Bioassays
Authors: Sahu Ranjeev K. , Katiyar Shashwat , Yadav Awadhesh K. , Kumar Narendra , Srivastava Jatin
Published: June 2008

In the present study, the toxicity assessment of tannery effluent was carried out in terms of percent phytotoxicity and shoot/root dry weight ratio. The effluent used in the study was collected from the outlet of an effluent treatment plant situated in the Jajmau area of Kanpur, U. P. India. Three varieties each of rice (Surya‐52, Jaya‐14 and Pant‐10), pulses (Lens‐(Type‐9), Gram Bahar, and Mung‐C‐K‐851) and oil seeds (Mustard RS‐30, B‐9 and T‐69) containing different kinds of reserve food materials, i. e., starch, protein and fat were taken for the toxicity study. The accumulations of heavy metals, i. e., Cr, Cu, Zn, and Ni, by these different crop varieties through pot culture irrigated with effluent were estimated at maturity. The concentration of heavy metals in the effluent was found to be Cr = 0.135, Cu = 0.065, Zn = 0.052, and Ni = 0.036 mg/L. The maximum concentration found in the plant tissue was seen in the mustard variety RS 30, i. e., Cr = 15.2, Cu = 4.4, Zn = 3.2, and Ni = 2.6 μg/g dry weight (d.w.) and the minimum concentration was found in Gram Bahar, i. e., Cr = 8.5, Cu = 2.0, Zn = 1.6 μg/g d.w., whereas, in 0.98 μg/g d.w. of Ni was found in the Surya rice variety. The percent phytotoxicity was found to be in the range of 10.4 to 25.6% amongst the different test varieties. The average percent phytotoxicity was found to be highest in rice followed by oilseed and pulses. The shoot/root dry weight ratio ranged between 10.82 to 14.22, with the highest value seen for rice (Pant‐10) and the lowest for a pulse (Gram‐Bahar). The results revealed that cultivation of these crops irrigated with the tannery effluent may pose a potential risk to humans as well as animals because of their bioaccumulation properties and ability to transfer metals from one trophic level to the next trophic level through the food chain. Since the percent phytotoxicity and shoot/root dry weight ratio behaves in a similar manner for the effluent, these parameters can be considered for the assessment of toxicity of industrial effluents.