bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of different options for harvest of a therapeutic protein product from high cell density yeast fermentation broth
Authors: Wang Alice , Lewus Rachael , Rathore Anurag S. 
Published: January 2006

AbstractRecovery of therapeutic protein from high cell density yeast fermentations at commercial scale is a challenging task. In this study, we investigate and compare three different harvest approaches, namely centrifugation followed by depth filtration, centrifugation followed by filter‐aid enhanced depth filtration, and microfiltration. This is achieved by presenting a case study involving recovery of a therapeutic protein from Pichia pastoris fermentation broth. The focus of this study is on performance of the depth filtration and the microfiltration steps. The experimental data has been fitted to the conventional models for cake filtration to evaluate specific cake resistance and cake compressibility. In the case of microfiltration, the experimental data agrees well with flux predicted by shear induced diffusion model. It is shown that, under optimal conditions, all three options can deliver the desired product recovery ( >80%), harvest time ( <15 h including sequential concentration/diafiltration step), and clarification ( <6 NTU). However, the three options differ in terms of process development time required, capital cost, consumable cost, ease of scale‐ability and process robustness. It is recommended that these be kept under consideration when making a final decision on a harvesting approach. © 2006 Wiley Periodicals, Inc.
Protein instability during HIC: Describing the effects of mobile phase conditions on instability and chromatographic retention
Authors: Xiao Yunzhi , Freed Alexander S. , Jones Tara Tibbs , Makrodimitris Kostantinos , O'Connell John P. , Fernandez Erik J. 
Published: January 2006

AbstractHydrophobic interaction chromatography (HIC) is known to be potentially denaturing to proteins, but the effects of mobile phase conditions on chromatographic behavior are not well understood. In this study, we apply a model describing the effects of secondary protein unfolding equilibrium on chromatographic behavior, including the effects of salt concentration on both stability and adsorption. We use α‐lactalbumin as a model protein that in the presence and absence of calcium, allows evaluation of adsorption parameters for folded and unfolded species independently. The HIC adsorption equilibrium under linear binding conditions and solution phase protein stability have been obtained from a combination of literature and new experiments. The effect of salt concentration on protein stability and the rate constant for unfolding on the chromatographic surface have been determined by fitting the model to isocratic chromatography data under marginally stable conditions. The model successfully describes the effects of added calcium and ammonium sulfate. The results demonstrate the importance of considering the effects on stability of mobile phase modifiers when applying HIC to marginally stable proteins. © 2006 Wiley Periodicals, Inc.
On the influence of oxygen and cell concentration in an SFPR whole cell biocatalytic Baeyer–Villiger oxidation process
Authors: Hilker Iris , Baldwin Chris , Alphand Véronique , Furstoss Roland , Woodley John , Wohlgemuth Roland 
Published: January 2006

AbstractEfficient whole cell biotransformations, in particular microbial whole cell Baeyer–Villiger oxidation with molecular oxygen, demand comprehension and optimization of the process details involved. Optimal provision of oxygen and control of bioprocess parameters are pivotal for their success. The interrelation of cell density and oxygen supply in an in situ substrate feeding and product removal (SFPR) whole cell Baeyer–Villiger oxidation process was investigated in detail. Both parameters were optimized with respect to practical considerations. The outcome of this study supports a schematic process model, allows estimation of optimum process conditions and exploration of its limits. © 2006 Wiley Periodicals, Inc.
Covalently immobilized enzyme gradients within three‐dimensional porous scaffolds
Authors: Vepari Charu P. , Kaplan David L. 
Published: January 2006

AbstractHorseradish peroxide (HRP) was covalently coupled to three‐dimensional (3D) silk fibroin scaffolds using water‐soluble carbodiimide. Stable, bilaterally symmetrical immobilized HRP gradient patterns were generated within 3D silk fibroin scaffolds using the principles of diffusion. Gradients of immobilized HRP activity were controlled using variables of volume and concentration of HRP solution activated by the carbodiimide. The method developed can be extended to immobilize a variety of proteins and small molecules on several types of porous, interconnected materials. This technique of patterning enzymes and proteins in a gradient manner offers new options in the field of chemotaxis, tissue engineering, and biosensors. © 2006 Wiley Periodicals, Inc.
Recovery of Homogeneous Polyoxometallate Catalysts from Aqueous and Organic Media by a Mesoporous Ceramic Membrane without Loss of Catalytic Activity
Authors: Roy Chowdhury Sankhanilay , Witte Peter T. , Blank Dave H. A. , Alsters Paul L. , ten Elshof Johan E. 
Published: January 2006

AbstractThe recovery of homogeneous polyoxometallate (POM) oxidation catalysts from aqueous and non‐aqueous media by a nanofiltration process using mesoporous γ‐alumina membranes is reported. The recovery of Q12[WZn3(ZnW9O34)2] (Q=[MeN(n‐C8H17)3]+) from toluene‐based media was quantitative within experimental error, while up to 97 % of Na12[WZn3(ZnW9O34)2] could be recovered from water. The toluene‐soluble POM catalyst was used repeatedly in the conversion of cyclooctene to cyclooctene oxide and separated from the product mixture after each reaction. The catalytic activity increased steadily with the number of times that the catalyst had been recycled, which was attributed to partial removal of the excess QCl that is known to have a negative influence on the catalytic activity. Differences in the permeability of the membrane for different liquid media can be attributed to viscosity differences and/or capillary condensation effects. The influence of membrane pore radius on permeability and recovery is discussed.
Polymorphism Versus Thermochromism: Interrelation of Color and Conformation in Overcrowded Bistricyclic Aromatic Enes
Authors: Biedermann P. Ulrich , Stezowski John J. , Agranat Israel 
Published: January 2006

AbstractThe nature of the thermochromic form of overcrowded bistricyclic aromatic enes (BAEs) has been controversial for a century. We report the single‐crystal X‐ray structure analysis of the deep‐purple and yellow polymorphs of 9‐(2,7‐dimethyl‐9H‐fluoren‐9‐ylidene)‐9H‐xanthene (11), which revealed the molecules in a twisted and a folded conformation, respectively. Therefore, the deeply colored thermochromic form B of BAEs is identified as having a twisted conformation and the ambient‐temperature form A as having a folded conformation. This relationship between the color and the conformation is further supported by the X‐ray structures of the deep‐purple crystals of the twisted 9‐(9H‐fluoren‐9‐ylidene)‐9H‐xanthene (10), and of the yellow crystals of the folded 9‐(11H‐benzo[b]fluoren‐11‐ylidene)‐9H‐xanthene (12). Based on this conclusive crystallographic evidence, eleven previously proposed rationales of thermochromism in BAEs are refuted. In the twisted structures, the tricyclic moieties are nearly planar and the central double bond is elongated to 1.40 Å and twisted by 42°. In the folded structures, the xanthylidene moieties are folded by 45° and the fluorenylidene moieties by 18–20°. Factors stabilizing the twisted and folded conformations are discussed, including twisting of formal single or double bonds, intramolecular overcrowding, and the significance of a dipolar aromatic “xanthenylium‐fluorenide” push–pull structure.
Anellated N‐Heterocyclic Carbenes: 1,3‐Dineopentylnaphtho[2,3‐d]imidazol‐2‐ylidene: Synthesis, KOH Addition Product, Transition‐Metal Complexes, and Anellation Effects
Authors: Saravanakumar Shanmuganathan , Oprea Anca I. , Kindermann Markus K. , Jones Peter G. , Heinicke Joachim 
Published: January 2006

AbstractTwo novel anellated N‐heterocyclic carbenes (NHC), 1,3‐dineopentylnaphtho[2,3‐d]imidazol‐2‐ylidene, and 1,3‐dineopentyl‐2‐ylido‐imidazolo[4,5‐b]pyridine were obtained by reduction of the respective thiones with potassium, the former also by deprotonation of the corresponding naphthimidazolium hexafluorophosphate by using excess KH in THF. The use of equimolar amounts of KH provided an unexpected formal addition product of this NHC with KOH. X‐ray crystal structure analysis of the adduct provided evidence for a distorted tetrameric N‐heterocyclic alkoxide, stabilized by two THF molecules. In C6D6 the compound undergoes disproportionation. Transition‐metal complexes [(NHC)AgCl], [(NHC)Rh(cod)Cl], and (E)‐[(NHC)2PdCl2] of the novel naphthimidazol‐2‐ylidene were synthesized. X‐ray crystal structures and 1H and 13C NMR spectroscopic data provided detailed structural information. Comparing characteristic data with those of nonanellated and differently anellated NHCs or their complexes provides information on the influence of the extended anellation.
Electronic Properties and Reactivity of Short‐Chain Oligomers of 3,4‐Phenylenedioxythiophene (PheDOT)
Authors: Perepichka Igor F. , Roquet Sophie , Leriche Philippe , Raimundo Jean‐Manuel , Frère Pierre , Roncali Jean 
Published: January 2006

AbstractThe dimer and trimer of 3,4‐phenylenedioxythiophene (PheDOT) have been synthesized. Unlike the parent systems based on 3,4‐ethylenedioxythiophene (EDOT), these compounds are quite stable under atmospheric conditions. The electronic absorption spectra of di‐ and tri‐PheDOT exhibit a well‐resolved vibronic fine structure indicative of self‐rigidification of the conjugated structure by noncovalent intramolecular sulfur–oxygen interactions. Comparison of UV‐visible data for the PheDOT oligomers with those of the corresponding EDOT oligomers reveals a faster decrease of the HOMO–LUMO gap with chain length for the former. Cyclic voltammetric data show that whereas PheDOT oxidizes at a lower potential than EDOT, the PheDOT dimer and trimer exhibit much higher oxidation potentials than their EDOT‐based analogues. A comparative analysis of the electropolymerization of the three PheDOT‐based systems shows that although PheDOT is very difficult to polymerize, its dimer and trimer can be readily electropolymerized. This unexpected increase of reactivity with chain extension is discussed with the aid of theoretical calculations.
The Importance of Alkali Cations in the [{RuCl2(p‐cymene)}2]–Pseudo‐dipeptide‐Catalyzed Enantioselective Transfer Hydrogenation of Ketones
Authors: Västilä Patrik , Zaitsev Alexey B. , Wettergren Jenny , Privalov Timofei , Adolfsson Hans 
Published: January 2006

AbstractWe studied the role of alkali cations in the [{RuCl2(p‐cymene)}2]–pseudo‐dipeptide‐catalyzed enantioselective transfer hydrogenation of ketones with isopropanol. Lithium salts were shown to increase the enantioselectivity of the reaction when iPrONa or iPrOK was used as the base. Similar transfer‐hydrogenation systems that employ chiral amino alcohol or monotosylated diamine ligands are not affected by the addition of lithium salts. These observations have led us to propose that an alternative reaction mechanism operates in pseudo‐dipeptide‐based systems, in which the alkali cation is an important player in the ligand‐assisted hydrogen‐transfer step. DFT calculations of the proposed transition‐state (TS) models involving different cations (Li+, Na+, and K+) confirm a considerable loosening of the TS with larger cations. This loosening may be responsible for the fewer interactions between the substrate and the catalytic complex, leading to lower enantiodifferentiation. This mechanistic hypothesis has found additional experimental support; the low ee obtained with [BnNMe3]OH (a large cation) as base can be dramatically improved by introducing lithium cations into the system. Also, the complexation of Na+, K+, and Li+ cations by the addition of [15]crown‐5 and [18]crown‐6 ethers and cryptand 2.1.1 (which selectively bind to these cations and, thus, increase their bulkiness), respectively, to the reaction mixture led to a significant drop in the enantioselectivity of the reaction. The lithium effect has proved useful for enhancing the reduction of different aromatic and heteroaromatic ketones.
Implications for clinical staging of metastatic cutaneous squamous carcinoma of the head and neck based on a multicenter study of treatment outcomes
Authors: Andruchow Jennifer L. , Veness Michael J. , Morgan Gary J. , Gao Kan , Clifford Anthony , Shannon Kerwin F. , Poulsen Michael , Kenny Lizbeth , Palme Carsten E. , Gullane Patrick , Morris Christopher , Mendenhall William M. , Patel Kepal N. , Shah Jatin P. , O'Brien Christopher J. 
Published: January 2006

AbstractBACKGROUNDCutaneous squamous cell carcinoma (SCC) of the head and neck is a common cancer that has the potential to metastasize to lymph nodes in the parotid gland and neck. Previous studies have highlighted limitations with the current TNM staging system for metastatic skin carcinoma. The aim of this study was to test a new staging system that may provide better discrimination between patient groups.METHODSA retrospective multicenter study was conducted on 322 patients from three Australian and three North American institutions. All had metastatic cutaneous SCC involving the parotid gland and/or neck and all were treated for cure with a minimum followup time of 2 years. These patients were restaged using a newly proposed system that separated parotid disease (P stage) from neck disease (N stage) and included subgroups of P and N stage. Metastases involved the parotid in 260 patients (149 P1; 78 P2; 33 P3) and 43 of these had clinical neck disease also (22 N1; 21 N2). Neck metastases alone occurred in 62 patients (26 N1; 36 N2). Ninety percent of patients were treated surgically and 267 of 322 received radiotherapy.RESULTSNeck nodes were pathologically involved in 32% of patients with parotid metastases. Disease recurred in 105 (33%) of the 322 patients, involving the parotid in 42, neck in 33, and distant sites in 30. Parotid recurrence did not vary significantly with P stage. Disease‐specific survival was 74% at 5 years. Survival was significantly worse for patients with advanced P stage: 69% survival at 5 years compared with 82% for those with early P stage (P = 0.02) and for those with both parotid and neck node involvement pathologically: 61% survival compared with 79% for those with parotid disease alone (P = 0.027). Both univariate and multivariate analysis confirmed these findings. Clinical neck involvement among patients with parotid metastases did not significantly worsen survival (P = 0.1).CONCLUSIONSThis study, which included a mixed cohort of patients from six different institutions, provides further information about the clinical behavior of metastatic cutaneous SCC of the head and neck. The hypothesis that separation of parotid and neck disease in a new staging system is supported by the results. The benefit of having subgroups of P and N stage is uncertain, but it is likely to identify patients with unfavorable characteristics that may benefit from further research. Cancer 2006. © 2006 American Cancer Society.
Disease‐free and overall survival after pathologic complete disease remission of cytologically proven inflammatory breast carcinoma axillary lymph node metastases after primary systemic chemotherapy
Authors: Hennessy Bryan T. , Gonzalez‐Angulo Ana Maria , Hortobagyi Gabriel N. , Cristofanilli Massimo , Kau Shu Wan , Broglio Kristine , Fornage Bruno , Singletary S. Eva , Sahin Aysegul , Buzdar Aman U. , Valero Vicente 
Published: January 2006

AbstractBACKGROUNDBreast carcinoma axillary lymph node (ALN) pathologic complete response (pCR) after primary chemotherapy is associated with significantly higher recurrence‐free survival (RFS) and overall survival (OS) rates. The purpose of the current study was to determine long‐term outcome in patients achieving a pCR of cytologically proven inflammatory breast carcinoma ALN metastases after primary chemotherapy.METHODSPatients with cytologically documented ALN metastases from inflammatory breast carcinoma were treated in three prospective primary chemotherapy trials. After surgery, patients were subdivided into those patients with and those patients without residual ALN carcinoma. Survival was calculated using the Kaplan–Meier method.RESULTSOf 175 patients treated, 61 had cytologically confirmed ALN metastases. Fourteen patients (23%) achieved a pCR of the ALNs after primary chemotherapy. The 5‐year OS and RFS rates were found to be improved in those patients achieving a pCR of the ALNs (82.5% [95% confidence interval (95% CI), 62.8–100%] and 78.6% [95%CI, 59.8–100%], respectively, vs. 37.1% [95%CI, 25.4–54.2%] and 25.4% [95%CI, 15.5–41.5%], respectively) (P = 0.01 [for OS] and P = 0.001 [for RFS]). Combination anthracycline and taxane‐based primary chemotherapy resulted in significantly more patients achieving an ALN pCR (45% vs. 16%; P = 0.01).CONCLUSIONSpCR of ALN metastases is associated with an excellent prognosis in patients with inflammatory breast carcinoma. The rates of ALN pCR are nearly 50% in patients with inflammatory breast carcinoma who are treated with anthracyclines and weekly paclitaxel before surgery. However, those patients with residual ALN disease at the time of surgery greatly require the introduction of novel therapeutic strategies. Cancer 2006. © 2006 American Cancer Society.
The end of the MFA and apparel exports: has good CSR allowed Cambodia to hold steady against China in a quota free environment?
Authors: Frost Stephen , Ho Mary 
Published: January 2006

AbstractIn the lead up the end of the Multi‐Fiber Arrangement (MFA), commentators routinely argued that Chinese apparel exports would surge in a quota‐free environment. It was also expected that Southeast Asian apparel exporting nations would suffer declines, leading to job and economic losses. Of particular concern was Cambodia, a country that relies almost exclusively on apparel exports for foreign earnings. By mid‐2005, as trade data started to filter in, the doomsday scenario for countries like Cambodia seemed less clear cut. Although China's apparel exports had indeed soured, a surprising outcome was that exports to the US from Cambodia (and several other neighbours such as Indonesia and Vietnam) had also increased. This article focuses specifically on Cambodia (which of all the Southeast Asian countries surveyed has shown the greatest growth in apparel exports) and examines some of the CSR initiatives that help explain why gloomy prognostications have not yet become true. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Tbx1 is regulated by forkhead proteins in the secondary heart field†
Authors: Maeda Jun , Yamagishi Hiroyuki , McAnally John , Yamagishi Chihiro , Srivastava Deepak 
Published: January 2006

AbstractTranscriptional regulation in a tissue‐specific and quantitative manner is essential for developmental events, including those involved in cardiovascular morphogenesis. Tbx1 is a T‐box–containing transcription factor that is responsible for many of the defects observed in 22q11 deletion syndrome in humans. Tbx1 is expressed in the secondary heart field (SHF) and is essential for cardiac outflow tract (OFT) development. We previously reported that Tbx1 is regulated by sonic hedgehog by means of forkhead (Fox) transcription factors in the head mesenchyme and pharyngeal endoderm, but how it is regulated in the SHF is unknown. Here, we show that Tbx1 expression in the SHF is regulated by Fox proteins through a combination of two evolutionarily conserved Fox binding sites in a dose‐dependent manner. Cell fate analysis using the Tbx1 enhancer suggests that SHF‐derived Tbx1‐expressing cells contribute extensively to the right ventricular myocardium as well as the OFT during early development and ultimately give rise to the right ventricular infundibulum, pulmonary trunk, and pulmonary valves. These results suggest that Fox proteins are involved in most, if not all, Tbx1 expression domains and that Tbx1 marks a subset of SHF‐derived cells, particularly those that uniquely contribute to the right‐sided outflow tract and proximal pulmonary artery. Developmental Dynamics 235:701–710, 2006. © 2006 Wiley‐Liss, Inc.
Newt orthologue of Growth arrest‐specific 6 (NvGas6) is implicated in stress response during newt forelimb regeneration
Authors: Beug Shawn , Vascotto Sandy G. , Tsilfidis Catherine 
Published: January 2006

AbstractRed‐spotted newts are capable of regenerating various structures and organs through the process of epimorphic regeneration. Receptor tyrosine kinases (RTKs) and their ligands are important for normal cellular development and physiology but most have not yet been characterised during regeneration. We have isolated a newt orthologue of Growth arrest‐specific 6 (NvGas6), and examined its expression during forelimb regeneration and within a blastema cell line (B1H1). During limb regeneration, NvGas6 expression increases upon amputation, peaks during maximal blastema cell proliferation, and is subsequently downregulated during redifferentiation. Transcripts are localised to the wound epithelium and distal mesenchymal cells during dedifferentiation and proliferative phases, and scattered within redifferentiating tissues during later stages. In B1H1 cultures, NvGas6 is upregulated under reduced serum conditions and myogenesis. Treatment with mimosine and colchicine or exposure to heat shock or anoxia results in upregulation of NvGas6 expression. Taken together, our findings suggest that during regeneration, NvGas6 expression may be upregulated in response to cellular stress. Developmental Dynamics 235:711–722, 2006. © 2006 Wiley‐Liss, Inc.
Two New CuII Coordination Polymers: Studies of Topological Networks and Water Clusters
Authors: Yang Jin , Ma Jian‐Fang , Liu Ying‐Ying , Ma Ji‐Cheng , Jia Heng‐Qing , Hu Ning‐Hai 
Published: January 2006

AbstractTwo new CuII coordination polymers, namely [Cu2(BDC)2(L)4(H2O)2]·14H2O (1) and [Cu1.5(BTC)(L)1.5(H2O)0.5]·2H2O (2), where L = 1,1′‐(1,4‐butanediyl)bis(imidazole), BDC = 1,4‐benzenedicarboxylate, and BTC = 1,3,5‐benzenetricarboxylate, have been synthesized at room temperature. Complex 1 exhibits an unusual, square‐planar, four‐connected 2D 264 net, which has been predicated by Wells. Interestingly, three types of water clusters, namely (H2O)6, (H2O)8, and (H2O)10, are observed in the hydrogen‐bonded layers constructed by the BDC ligands and water molecules. The BTC anion in compound 2 is coordinated to the CuII cation as tetradentate ligand to form a (66)2(426484)2(64810) net containing three kinds of nonequivalent points. Thermogravimetric analyses (TGA) and IR spectra for 1 and 2 are also discussed in detail. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)