bluuebunny/crossref_metadata_2025_split huggingface dataset:
Furfural, 5‐hydroxymethyl furfural, and acetoin act as external electron acceptors during anaerobic fermentation of xylose in recombinant Saccharomyces cerevisiae
Authors: Wahlbom C. Fredrik , Hahn–Hägerdal Bärbel 
Published: November 2004

AbstractThe electron acceptors acetoin, acetaldehyde, furfural, and 5‐hydroxymethylfurfural (HMF) were added to anaerobic batch fermentation of xylose by recombinant, xylose utilising Saccharomyces cerevisiae TMB 3001. The intracellular fluxes during xylose fermentation before and after acetoin addition were calculated with metabolic flux analysis. Acetoin halted xylitol excretion and decreased the flux through the oxidative pentose phosphate pathway. The yield of ethanol increased from 0.62 mol ethanol/mol xylose to 1.35 mol ethanol/mol xylose, and the cell more than doubled its specific ATP production after acetoin addition compared to fermentation of xylose only. This did, however, not result in biomass growth. The xylitol excretion was also decreased by furfural and acetaldehyde but was unchanged by HMF. Thus, furfural present in lignocellulosic hydrolysate can be beneficial for ethanolic fermentation of xylose. Enzymatic analyses showed that the reduction of acetoin and furfural required NADH, whereas the reduction of HMF required NADPH. The enzymatic activity responsible for furfural reduction was considerably higher than for HMF reduction and also in situ furfural conversion was higher than HMF conversion. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 172–178, 2002; DOI 10.1002/bit.10188
Pulsed electric field stimulates plant secondary metabolism in suspension cultures of Taxus chinensis*
Authors: Ye Hong , Huang Lin‐Ling , Chen Shu‐De , Zhong Jian‐Jiang 
Published: November 2004

AbstractThe effects of pulsed electric field (PEF) on growth and secondary metabolite production by plant cell culture were investigated by using suspension cultures of Taxus chinensis as a model system. Cultured cells in different growth phases were exposed to a PEF (50 Hz, 10 V/m) for various periods of time. A significant increase in intracellular accumulation of taxuyunnanine C (Tc), a bioactive secondary metabolite, was observed by exposing the cells in the early exponential growth phase to a 30‐min PEF. The Tc content (i.e., the specific production based on dry cell weight) was increased by 30% after exposure to PEF, without loss of biomass, compared with the control. The combination of PEF treatment and sucrose feeding proved useful for improving secondary metabolite formation. Production levels of reactive oxygen species, extracellular Tc, and phenolics were all increased, whereas cell capacitance was decreased with PEF treatment. The results show that PEF induced a defense response of plant cells and may have altered the cell/membrane's dielectric properties. PEF, an external stimulus or stress, is proposed as a promising new abiotic elicitor for stimulating secondary metabolite biosynthesis in plant cell cultures. © 2004 Wiley Periodicals, Inc.
Comparative proteomic analysis of GS‐NS0 murine myeloma cell lines with varying recombinant monoclonal antibody production rate
Authors: Smales C.M. , Dinnis D.M. , Stansfield S.H. , Alete D. , Sage E.A. , Birch J.R. , Racher A.J. , Marshall C.T. , James D.C. 
Published: November 2004

AbstractWe have employed an inverse engineering strategy based on quantitative proteome analysis to identify changes in intracellular protein abundance that correlate with increased specific recombinant monoclonal antibody production (qMab) by engineered murine myeloma (NS0) cells. Four homogeneous NS0 cell lines differing in qMab were isolated from a pool of primary transfectants. The proteome of each stably transfected cell line was analyzed at mid‐exponential growth phase by two‐dimensional gel electrophoresis (2D‐PAGE) and individual protein spot volume data derived from digitized gel images were compared statistically. To identify changes in protein abundance associated with qMab datasets were screened for proteins that exhibited either a linear correlation with cell line qMab or a conserved change in abundance specific only to the cell line with highest qMab. Several proteins with altered abundance were identified by mass spectrometry. Proteins exhibiting a significant increase in abundance with increasing qMab included molecular chaperones known to interact directly with nascent immunoglobulins during their folding and assembly (e.g., BiP, endoplasmin, protein disulfide isomerase). 2D‐PAGE analysis showed that in all cell lines Mab light chain was more abundant than heavy chain, indicating that this is a likely prerequisite for efficient Mab production. In summary, these data reveal both the adaptive responses and molecular mechanisms enabling mammalian cells in culture to achieve high‐level recombinant monoclonal antibody production. © 2004 Wiley Periodicals, Inc.
Mineralization of LCFA associated with anaerobic sludge: Kinetics, enhancement of methanogenic activity, and effect of VFA
Authors: Pereira M.A. , Sousa D.Z. , Mota M. , Alves M.M. 
Published: November 2004

AbstractLong‐chain fatty acids (LCFA) associated with anaerobic sludge by mechanisms of precipitation, adsorption, or entrapment can be biodegraded to methane. The mineralization kinetics of biomass‐associated LCFA were established according to an inhibition model based on Haldane's enzymatic inhibition kinetics. A value around 1,000 mg COD‐LCFA·.g VSS−1 was obtained for the optimal specific LCFA content that allowed the maximal mineralization rate. For sludge with specific LCFA contents of 2,838 ± 63 and 4,571 ± 257 mg COD‐LCFA·.g VSS−1, the specific methanogenic activities in the presence of acetate, butyrate, and H2/CO2 were significantly enhanced after the mineralization of the biomass‐associated LCFA. For sludge with a specific LCFA content near the optimal value defined by the kinetic model, the effect of adding VFA to the medium was studied during the mineralization of the biomass‐associated LCFA. Different patterns were obtained for each individual substrate. Acetate and butyrate were preferentially consumed by the consortium, but in the case of propionate no evidence of a sequential consumption pattern could be withdrawn. It was concluded that LCFA do not exert a bactericidal neither a permanent toxic effect toward the anaerobic consortia. A discussion is addressed to the relative roles of a reversible inhibitory effect and a transport limitation effect imposed by the LCFA surrounding the cells. © 2004 Wiley Periodicals, Inc.
Aggressive fibromatosis of the abdominal wall, limbs and limb girdles
Authors: Phillips S R , A'Hern R , Thomas J M 
Published: November 2004

AbstractBackgroundAggressive fibromatosis (AF) is a rare soft-tissue tumour. It is histologically benign but locally aggressive and destructive. Surgery is the mainstay of treatment. This was a review of patients treated at the Royal Marsden Hospital between 1986 and 2003.MethodsRecords of patients with abdominal wall (23) and limb or limb girdle (86) AF were studied to determine patient, tumour and treatment characteristics and outcome. Children and patients with intra-abdominal AF were excluded. The data were analysed by Cox regression to calculate univariate hazard ratios.ResultsTwenty-one (19·3 per cent) of 109 patients developed recurrence after a median follow-up of 39 months. Recurrence did not correlate with surgical margin or any other variable.ConclusionWide excisional, function-preserving surgery is the goal in treatment of AF. Surgery for recurrent disease is often curative. Tumours are frequently irresectable at presentation and an initial period of expectant observation is advisable because growth arrest is a common feature of the disease.
Randomized clinical trial comparing radioisotope occult lesion localization and wire-guided excision for biopsy of occult breast lesions
Authors: Rampaul R S , Bagnall M , Burrell H , Pinder S E , Evans A J , Macmillan R D 
Published: November 2004

Abstract

Background
Accurate localization of impalpable breast lesions that require biopsy is important. This randomized trial compared radioisotope occult lesion localization (ROLL) with the standard hooked-wire technique.

Methods
Ninety-five patients were randomized to receive either ROLL or wire localization of an occult breast lesion. Correct placement of isotope was confirmed by mammography and a hand-held γ probe was used to guide the surgical excision. Radiological, surgical and pathological data were compared for accuracy, duration and ease of technique, and histopathological diagnosis. Procedure-related pain was also assessed.

Results
Of the 95 patients entered, 48 were randomized to ROLL and 47 to wire localization. Two ROLL procedures failed. Marking was accurate in 46 of 48 ROLL procedures and 44 of 47 of wire localizations (P = 0·242). Difficulty in localization (Likert score 2·6 for ROLL versus 4·4 for wire localization; P &lt; 0·001) and the degree of surgical difficulty (2·6 versus 4·0; P &lt; 0·001) were significantly less for ROLL. ROLL was associated with less pain (score 2·7 versus 3·6; P = 0·012). There were no significant differences in mean duration of operation, specimen weight, need for intraoperative re-excision or second therapeutic operation.

Conclusion
ROLL and wire-guided localization were similarly effective for breast biopsy, but ROLL was easier for both radiologist and surgeon, and less painful for the patient.
Surgical management of primary and recurrent retroperitoneal liposarcoma
Authors: Neuhaus S J , Barry P , Clark M A , Hayes A J , Fisher C , Thomas J M 
Published: November 2004

Abstract

Background
Surgery plays a dominant role in the initial and subsequent treatment of retroperitoneal liposarcoma (RPLS). This study was a review of outcomes of patients treated at the Royal Marsden Hospital.

Methods
Records of all patients who had surgery for RPLS since 1990 were reviewed, with particular attention to local recurrence and disease-specific survival. Patients with primary RPLS and those with recurrent RPLS, who had palliative surgery after a variable number of operations performed elsewhere, were considered separately.

Results
Seventy-two patients had surgery for primary RPLS, over half of whom underwent resection of a contiguous organ to achieve clearance. Follow-up of at least 12 months was available for 58 patients. Thirty-four patients had no evidence of recurrence after median follow-up of 26 (range 12–151) months. Low-grade tumour and macroscopic clearance of tumour were significantly associated with a reduced risk of local recurrence and improved survival. Forty-seven patients had palliative surgery for recurrent RPLS. Median survival from time of last operation to death was 27 (range 0–79) months. Follow-up was to a median of 68 (range 14–261) months.

Conclusion
Patients with low-grade RPLS that has been completely resected at the initial operation have the most favourable prognosis. Palliative resection is worthwhile to treat troublesome symptoms of recurrence
Implications of screening for abdominal aortic aneurysms on surgical workload
Authors: Kim L G , Scott R A P , Thompson S G , Collin J , Morris G E , Sutton G L , Wilson N M 
Published: November 2004

Abstract

Background
The Multicentre Aneurysm Screening Study (MASS) provided strong evidence for both the clinical benefit and the cost-effectiveness of a screening programme for abdominal aortic aneurysms (AAAs) in men. If a national screening programme for AAA were adopted in the UK, it would be expected to increase the elective and decrease the emergency surgical workload.

Methods
The MASS trial randomized 67 800 men aged 65–74 years to be invited to attend for ultrasonographic screening for AAA or to a control group that received no invitation. Predictions of elective and emergency surgical workload were made for a 20-year interval after the introduction of a screening programme for 65-year-old men, based on surgical rates observed in the MASS trial and national mortality statistics.

Results
For a district general hospital serving a population of 400 000, there was an estimated reduction from nine emergency operations per year before introduction of the screening programme to three emergency operations annually in men aged 65 years and over by the end of the 20-year interval, and an increase from 24 to 43 AAA operations overall. The corresponding estimated annual costs for all AAA surgery increased by 47 per cent, from £209 000 to £308 000. These results were not affected by changes in the underlying assumptions.

Conclusion
The results support the expectation of very few emergency operations, and principally elective operations, being performed following the introduction of a screening programme. For a typical district general hospital, a screening programme would be expected to lead to two additional elective AAA operations per month, and to save 11 AAA-related deaths per year.
Environmental practices and the value added of horticultural firms
Authors: Céspedes‐Lorente José , Galdeano‐Gómez Emilio 
Published: November 2004

AbstractThis paper explores the relationship between environmental management and productivity in the fruit and vegetable sector. Our empirical analysis focuses on the effect of environmental practices on the value added in horticultural firms of Andalusia. These practices are included in the incentive programmes established by the Common Agricultural Policy on a voluntary basis. Taking the investment in environmental activities as knowledge capital, we propose a specific analysis that evaluates the effect of the factors of the production function on the value added. Our results show a positive overall impact of environmental investment on the product's market value. We conclude that there is a direct link between environmental management and productivity in the sector under study. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
Oligonucleotide Bearing Ethylenediamine‐N,N,N′‐Triacetates for Gap‐Selective DNA Hydrolysis by Ce4+/EDTA
Authors: Komiyama Makoto , Arishima Hiroyuki , Yokoyama Masahito , Kitamura Yoshihito , Yamamoto Yoji 
Published: November 2004

AbstractWith the use of two oligonucleotides bearing ethylenediamine‐N,N,N′‐triacetate groups as additives, gap sites were formed at predetermined sites in substrate DNA. Upon treating these systems with a Ce4+/EDTA complex at pH 7.0 and 37 °C, the phosphodiester linkages at the gap site were selectively hydrolyzed. The DNA scission was greatly promoted by the introduction of ethylenediaminetriacetate groups, and the scission efficiency increased as the number of these groups increased. Even a one‐base gap was successfully hydrolyzed when three ethylenediaminetriacetate groups were placed consecutively at both edges of the gap, although the scission was minimal in the absence of these groups. The site‐selective scission could be also achieved at higher temperatures without any significant loss of site‐selectivity.
Large Bubble Sizes and Rise Velocities in a Bubble Column Slurry Reactor
Authors: Vandu C.O. , Koop K. , Krishna R. 
Published: November 2004

AbstractThe results are reported of an experimental study of the gas holdup, ϵG, large bubble diameter, dLb, and large bubble rise velocity, VLb, in a 0.1 m wide, 0.02 m deep and 0.95 m high rectangular slurry bubble column operated at ambient temperature and pressure conditions. The superficial gas velocity U was varied in the range of 0–0.2 m/s, spanning both the homogeneous and heterogeneous flow regimes. Air was used as the gas phase. The liquid phase used was C9‐C11 paraffin oil containing varying volume fractions (ϵS = 0, 0.05, 0.10, 0.15, 0.20 and 0.25) of porous catalyst (alumina catalyst support, 10 % < 10 μm; 50 % < 16 μm; 90 % < 39 μm). With increasing slurry concentrations, ϵG is significantly reduced due to enhanced bubble coalescence and for high slurry concentrations the “small” bubbles are significantly reduced in number. By the use of video imaging techniques, it was shown that the large bubble diameter is practically independent of the gas velocity for ϵS > 0.05 and U > 0.1 m/s. The measured large bubble rise velocity VLb agrees with the predictions of a modified Davis‐Taylor relationship.
An introduction to decision tree modeling
Authors: Myles Anthony J. , Feudale Robert N. , Liu Yang , Woody Nathaniel A. , Brown Steven D. 
Published: November 2004

AbstractIn this tutorial, traditional decision tree construction and the current state of decision tree modeling are reviewed. Emphasis is placed on techniques that make decision trees well suited to handle the complexities of chemical and biochemical applications. Copyright © 2004 John Wiley & Sons, Ltd.
Aryl Cation and Carbene Intermediates in the Photodehalogenation of Chlorophenols
Authors: Manet Ilse , Monti Sandra , Fagnoni Maurizio , Protti Stefano , Albini Angelo 
Published: November 2004

AbstractThe photochemistry of 2,6‐dimethyl‐4‐chlorophenol (6) has been studied in methanol and trifluoroethanol (TFE) through product studies and transient absorption spectroscopy. Chloride loss from triplet 6 gave triplet hydroxyphenyl cation 14, which equilibrated with triplet oxocyclohexadienylydene 15 within a few tens of nanoseconds; the cation can, however, be selectively trapped by allyltrimethylsilane (kad = 108–109  m−1 s−1) to give a phenonium ion and the allylated phenol. In neat alcohols, 14 and 15 are reduced through different mechanisms, namely by hydrogen transfer through radical cation 17 and via phenoxyl radical 16, respectively. The mechanistic rationalization has been substantiated by the parallel study of an O‐silylated derivative. The work shows that the chemistry of the highly (but selectively) reactive phenyl cation 14 can not only be discriminated from that of the likewise highly reactive carbene 15, but also exploited for synthetically useful reactions, as in this case with alkenes. Photolysis of electron‐donating substituted halobenzenes may be the method of choice for the mild generation of some classes of phenyl cations.
On the Gas‐Phase Reactivity of Complexed OH+ with Halogenated Alkanes
Authors: Adlhart Christian , Sekiguchi Osamu , Uggerud Einar 
Published: November 2004

AbstractOH+ is an extraordinarily strong oxidant. Complexed forms (LOH+), such as H2OOH+, H3NOH+, or iron–porphyrin‐OH+ are the anticipated oxidants in many chemical reactions. While these molecules are typically not stable in solution, their isolation can be achieved in the gas phase. We report a systematic survey of the influence on L on the reactivity of LOH+ towards alkanes and halogenated alkanes, showing the tremendous influence of L on the reactivity of LOH+. With the help of with quantum chemical calculations, detailed mechanistic insights on these very general reactions are gained. The gas‐phase pseudo‐first‐order reaction rates of H2OOH+, H3NOH+, and protonated 4‐picoline‐N‐oxide towards isobutane and different halogenated alkanes CnH2n+1Cl (n=1–4), HCF3, CF4, and CF2Cl2 have been determined by means of Fourier transform ion cyclotron resonance meaurements. Reaction rates for H2OOH+ are generally fast (7.2×10−10–3.0×10−9 cm3 mol−1 s−1) and only in the cases HCF3 and CF4 no reactivity is observed. In contrast to this H3NOH+ only reacts with tC4H9Cl (kobs=9.2×10−10), while 4‐CH3‐C5H4N‐OH+ is completely unreactive. While H2OOH+ oxidizes alkanes by an initial hydride abstraction upon formation of a carbocation, it reacts with halogenated alkanes at the chlorine atom. Two mechanistic scenarios, namely oxidation at the halogen atom or proton transfer are found. Accurate proton affinities for HOOH, NH2OH, a series of alkanes CnH2n+2 (n=1–4), and halogenated alkanes CnH2n+1Cl (n=1–4), HCF3, CF4, and CF2Cl2, were calculated by using the G3 method and are in excellent agreement with experimental values, where available. The G3 enthalpies of reaction are also consistent with the observed products. The tendency for oxidation of alkanes by hydride abstraction is expressed in terms of G3 hydride affinities of the corresponding cationic products CnH2n+1+ (n=1–4) and CnH2nCl+ (n=1–4). The hypersurface for the reaction of H2OOH+ with CH3Cl and C2H5Cl was calculated at the B3 LYP, MP2, and G3m* level, underlining the three mechanistic scenarios in which the reaction is either induced by oxidation at the hydrogen or the halogen atom, or by proton transfer.
Homocoenzyme B12 and Bishomocoenzyme B12: Covalent Structural Mimics for Homolyzed, Enzyme‐Bound Coenzyme B12
Authors: Gschösser Sigrid , Hannak Renate B. , Konrat Robert , Gruber Karl , Mikl Christian , Kratky Christoph , Kräutler Bernhard 
Published: November 2004

AbstractEfficient electrochemical syntheses of “homocoenzyme B12” (2, Coβ‐(5′‐deoxy‐5′‐adenosyl‐methyl)‐cob(III)alamin) and “bishomocoenzyme B12” (3, Coβ‐[2‐(5′‐deoxy‐5′‐adenosyl)‐ethyl]‐cob(III)alamin) are reported here. These syntheses have provided crystalline samples of 2 and 3 in 94 and 77 % yield, respectively. In addition, in‐depth investigations of the structures of 2 and 3 in solution were carried out and a high‐resolution crystal structure of 2 was obtained. The two homologues of coenzyme B12 (2 and 3) are suggested to function as covalent structural mimics of the hypothetical enzyme‐bound “activated” (that is, “stretched” or even homolytically cleaved) states of the B12 cofactor. From crude molecular models, the crucial distances from the corrin‐bound cobalt center to the C5′ atom of the (homo)adenosine moieties in 2 and 3 were estimated to be about 3.0 and 4.4 Å, respectively. These values are roughly the same as those found in the two “activated” forms of coenzyme B12 in the crystal structure of glutamate mutase. Indeed, in the crystal structure of 2, the cobalt center was observed to be at a distance of 2.99 Å from the C5′ atom of the homoadenosine moiety and the latter was found to be present in the unusual syn conformation. In solution, the organometallic moieties of 2 and 3 were shown to be rather flexible and to be considerably more dynamic than the equivalent group in coenzyme B12. The homoadenosine moiety of 2 was indicated to occur in both the syn and the anti conformations.