bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interfacing Pichia pastoris cultivation with expanded bed adsorption
Authors: Jahic Mehmedalija , Knoblechner Josef , Charoenrat Theppanya , Enfors Sven‐Olof , Veide Andres 
Published: January 2006

AbstractFor improved interfacing of the Pichia pastoris fed‐batch cultivation process with expanded bed adsorption (EBA) technique, a modified cultivation technique was developed. The modification included the reduction of the medium salt concentration, which was then kept constant by regulating the medium conductivity at low value (about 8 mS/cm) by salt feeding. Before loading, the low conductivity culture broth was diluted only to reduce viscosity, caused by high cell density. The concept was applied to a one‐step recovery and purification procedure for a fusion protein composed of a cellulose‐binding module (CBM) from Neocallimastix patriciarum cellulase 6A fused to lipase B from Candida antarctica (CALB). The modified cultivation technique resulted in lower cell death and consequently lower concentration of proteases and other contaminating proteins in the culture broth. Flow cytometry analysis showed 1% dead (propidium‐stained) cells compared to 3.5% in the reference process. During the whole process of cultivation and recovery, no proteolysis was detected and in the end of the cultivation, the product constituted 87% of the total supernatant protein. The lipase activity in the culture supernatant increased at an almost constant rate up to a value corresponding to 2.2 g/L of CBM–CALB. In the EBA process, no cell‐adsorbent interaction was detected but the cell density had to be reduced by a two‐times dilution to keep a proper bed expansion. At flow velocity of 400 cm/h, the breakthrough capacity was 12.4 g/L, the product yield 98%, the concentration factor 3.6 times, the purity about 90%, and the productivity 2.1 g/L · h. © 2006 Wiley Periodicals, Inc.
Captopril protects mice bone marrow cells against genotoxicity induced by gamma irradiation
Authors: Hosseinimehr Seyed Jalal , Mahmoudzadeh Aziz , Akhlagpour Shahram 
Published: January 2006

AbstractThe radioprotective effects of captopril were investigated by using the micronucleus test for anticlastogenic and cell proliferation activity. A single intraperitoneal administration of captopril at doses of 10, 25 and 50 mg/kg 1 h prior to gamma irradiation (2 Gy) reduced the frequencies of micronuleated polychromatic erythrocytes (MnPCEs). All three doses of captopril significantly reduced the frequencies of MnPCEs and increased polychromatic erythrocytes (PCE)/PCE+NCE (normochromatic erythrocyte) ratio in mice bone marrow compared to the non‐drug‐treated irradiated control (p < 0.001). The optimum dose for protection in mouse was 10 mg/kg to protect mice bone marrow 2.18‐fold against the clastogenic effects of γ‐irradiation with respect to the non‐drug‐treated irradiated control. There was a drug dose‐response effect of captopril in increasing the PCE/PCE+NCE ratio in bone marrow cells. The maximum protective effect of captopril was at a dose of 25 mg/kg for increasing the PCE/PCE + NCE ratio. Captopril exhibited concentration‐dependent antioxidant activity, scavenging > 96% of the 1,1‐diphenyl‐2‐picryl hydrazyl free radicals when used at a concentration of 0.2 mM. In this study captopril reduced lipid peroxidation induced by hydrogen peroxide in mice liver. It appears that captopril, due to its free radical scavenging properties, protects mice bone marrow cells from radiation‐induced DNA damage and genotoxicity. Copyright © 2006 John Wiley & Sons, Ltd.
Lipid peroxidation in liver tissue of ovariectomized and pinealectomized rats: effect of estradiol and progesterone supplementation
Authors: Oztekin Esma , Tiftik Ali Muhtar , Baltaci Abdulkerim Kasim , Mogulkoc Rasim 
Published: January 2006

AbstractThe present study aimed to determine the effect of estradiol‐progesterone supplementation and pinealectomy on lipid peroxidation of liver tissue in ovariectomized rats.The study was carried out on 36 adult Sprague‐Dawley female rats, which weighed 200–250 g. The rats were divided into 6 groups: Group 1: Sham Ovariectomy (Sham‐Ovx), Group 2: Ovariectomy (Ovx), Group 3: Ovx + Estradiol‐Progesterone supplementation (Ovx + H), Group 4: Sham Pinealectomy and Ovx (Sham Pnx ‐Ovx), Group 5: Ovx ‐Pnx, Group 6: Ovx ‐Pnx + H. Malondialdehyde (MDA), reduced form of glutathione (GSH) and glutathione peroxidase (GSH‐Px) levels were determined in liver tissue of rats.The highest MDA levels and the lowest GSH‐Px levels were determined in the ovariectomized‐pinealectomized group, whereas the lowest MDA was in the Sham‐Ovx group, and the highest GSH‐Px levels were found in the Sham‐Ovx and Ovx + Hormone supplemented group. Furthermore, the highest GSH levels were in group 1 and lowest levels were in group 5.The findings of this study demonstrate that ovariectomy led to lipid peroxidation in liver tissues of rats. Pinealectomy in addition to ovariectomy, increases lipid peroxidation, but, estradiol and progesterone supplementations to the ovariectomized‐pinealectomized rats protect against lipid peroxidation to a significant extent. Copyright © 2006 John Wiley & Sons, Ltd.
Unexpected Oxidation of a Depsipeptide Substrate Analogue in Crystalline Isopenicillin N Synthase
Authors: Daruzzaman Adam , Clifton Ian J. , Adlington Robert M. , Baldwin Jack E. , Rutledge Peter J. 
Published: January 2006

AbstractIsopenicillin N synthase (IPNS) is a non‐heme iron(ii)‐dependent oxidase that is central to penicillin biosynthesis. Herein, we report mechanistic studies of the IPNS reaction in the crystalline state, using the substrate analogue δ‐(L‐α‐aminoadipoyl)‐(3R)‐methyl‐L‐cysteine D‐α‐hydroxyisovaleryl ester (AmCOV) to probe the early stages of the catalytic cycle. The X‐ray crystal structure of the anaerobic IPNS:FeII:AmCOV complex was solved to 1.40 Å resolution, and it reveals several subtle differences in the active site relative to the complex of the enzyme with its natural substrate. The crystalline IPNS:FeII:AmCOV complex was then exposed to oxygen gas at high pressure; this brought about reaction to give what appears to be a hydroxymethyl/ene‐thiol product. A mechanism for this reaction is proposed. These results offer further insight into the delicate interplay of steric and electronic effects in the IPNS active site and the mechanistic intricacies of this remarkable enzyme.
C‐Terminal Modifications of a Protein by UAG‐Encoded Incorporation of Puromycin during in vitro Protein Synthesis in the Absence of Release Factor 1
Authors: Agafonov Dmitry E. , Rabe Kersten S. , Grote Michael , Voertler C. Stefan , Sprinzl Mathias 
Published: January 2006

AbstractDeactivation of release factor 1 by polyclonal antibodies in an in vitro translation system, which was used to express the esterase gene, led to the reversible elimination of naturally occurring termination. This technique allowed the antibiotic puromycin to be used as an acceptor substrate for the peptidyl residue in the peptidyl‐transferase reaction. This resulted in more than 80 % yield of protein with C‐terminally incorporated puromycin. pCpPuromycin that was either conjugated with the Cy3 fluorophor or biotin by N4 alkylation of cytosine, also acted as an acceptor substrate for the peptidyl‐transferase reaction and was incorporated into the protein C terminus. The resulting conjugates possessed Cy3‐specific fluorescence and affinity to streptavidin‐coated surfaces, respectively. This left the enzymatic activity of the reporter protein unaffected. It was also shown that extension of puromycin on its 5′‐hydroxyl end by up to ten deoxyoligonucleotides also allowed conjugation with the C terminus of in vitro translated protein when RF1‐dependent termination was suppressed. However, the conjugation yield decreased upon addition of more than six nucleotides.
Prediction of Dextrose Nucleation Kinetics by the Growth Rate of Crystallites
Authors: Parisi M. , Rivallin M. , Chianese A. 
Published: January 2006

AbstractAn investigation on the dextrose nucleation carried out in the presence of seeds is reported. Induction time and nucleation point were measured in seeded solutions by eye and by using a nephelometer. The nucleation point was interpreted as the instant when crystallites, generated by seeds, grow up to crystals of detectable size. By applying the approach proposed by Kashchiev [1], the induction time values obtained were satisfactorily predicted when a birth and spread growth rate model was assumed. Moreover, by extending the same approach to the prediction of the nucleation point, obtained by linear cooling, a nucleation curve in good agreement with the experimental points was determined.
Effect of Fluid Dynamics on Particle Size Distribution in Particulate Processes
Authors: Marchisio D. L. , Soos M. , Sefcik J. , Morbidelli M. , Barresi A. A. , Baldi G. 
Published: January 2006

AbstractThe final product quality of crystallization and precipitation processes is often determined by the interplay between mixing and relevant phenomena such as, nucleation, molecular growth, aggregation and breakage. In this work the attention is focused on the aggregation and breakage processes and on the level of details needed to accurately describe them. Different modeling approaches are tested and compared for two different shear devices: a Taylor‐Couette cell and a stirred tank. Results show that when aggregation and breakage processes are much slower than mixing a simplified homogeneous model can be used whereas when aggregation and breakage occur on a time‐scale comparable with that of mixing then a detailed approach based on computational fluid dynamics (CFD) is needed. The very common lumped model, used to derive kinetic expressions for aggregation and breakage rates, can eventually lead to serious errors.
Pharmaceutical Compound Crystallization: Growth Mechanism of Needle‐Like Crystals
Authors: Taulelle P. , Astier J. P. , Hoff C. , Pèpe G. , Veesler S. 
Published: January 2006

AbstractIn this paper, crystallization of needle‐like crystals is investigated using both experimental and numerical approaches. The structure, morphology, habit, and growth behavior of Irbesatan phase A grown from 2‐propanol solution are studied. In this case, molecular modeling shows an unusually high anisotropy of the internal crystal structure, leading to the prediction of an acicular habit which is in good agreement with the experimental habit. Irbesartan phase A is an example of crystals for which the properties are governed by internal properties rather than external properties. The influence of the growth conditions is investigated by in situ and ex situ monitoring, namely optical microscopy and AFM. These investigations show that crystals are agglomerated with the same crystallographic orientation as the individual constituent; this was explained by regular over‐ and intergrowths as in the case of twinning.
Influence of Crystallization Conditions on Rheology and Microstructure of Dense Suspensions of Crystals of Eflucimibe
Authors: Teychene S. , Autret J. M. , Biscans B. 
Published: January 2006

AbstractThe crystallization process of eflucimibe, a new ACAT inhibitor, was carried out in a mixture of two solvents, ethanol and n‐heptane, by cooling. During the process, as the volume fraction of crystals was raised, the suspension went towards a very structured gel‐like network. This phenomenon acts as a brake to the extrapolation of the process. Experiments were carried out in a glass double‐jacketed 750 mL reactor in a LABMAX controlled system. At the end of the crystallization, rheological flow characteristics at constant ambient temperature were determined. The samples behave like a plastic fluid. The evolution of the elastic and viscous moduli as a function of the applied strain for a given oscillation frequency was measured. The results showed that the variation of the elastic modulus with particle concentration follows a power law. It was shown that for particle concentration higher than 2 % (volume fraction) needle‐like growing crystals form a network in which solvent is trapped.
Thermodynamic Predictions of Physical Properties – Prediction of Solid Solutions in Molecular Solutes Exhibiting Polymorphism
Authors: Coquerel G. 
Published: January 2006

AbstractPolymorphism is a widespread phenomenon among molecular components, and usually the lattice energies of the different varieties are rather close. It is shown that solid solutions, by means of insertion (e.g., due to solvent) or by means of substitution (e.g., due to derivatives of the components), can substantially modify the energy landscape between polymorphs. Fluctuations in the transition temperatures lead to the prediction of the existence of solid solutions.
Polymorphism of Active Pharmaceutical Ingredients
Authors: Karpinski P. H. 
Published: January 2006

AbstractDifferent polymorphs of the same active pharmaceutical ingredient (API) display distinct physical properties, such as melting point, solubility, dissolution rate, hygroscopicity, or stability. The ability to successfully produce and reproduce specific stable polymorphs is intricately correlated with the efficiency and speed of drug development, the robustness of manufacturing process, and – ultimately – the stability and quality of APIs. This paper focuses on eight case study examples of interesting polymorphic transformations observed in the course of the regular API development process. Through extensive physicochemical characterization, using multiple analytical techniques, the phenomena observed could be elucidated and proper measures recommended to reduce the risk of unexpected polymorphic transformations.
Prins‐Type Synthesis and SAR Study of Cytotoxic Alkyl Chloro Dihydropyrans
Authors: Miranda Pedro O. , Padrón José M. , Padrón Juan I. , Villar Jesús , Martín Víctor S. 
Published: January 2006

AbstractA series of functionalized tetrahydropyran and dihydropyran derivatives was synthesized by means of a Prins‐type cyclization between unsaturated alcohols and several aldehydes. An unprecedented dimer bearing two 4‐chloro‐5,6‐dihydro‐2H‐pyran scaffolds was obtained in high yield. A panel of three representative human solid tumor cells from diverse origin was used to assess the cytotoxicity of the compounds. Overall, the results show the relevance of the chlorovinyl group in the biological activity, and 2‐alkyl‐4‐chloro‐5,6‐dihydro‐2H‐pyrans represent interesting leads for further chemical modifications and biological studies.
Glucokinase mutations in young children with hyperglycemia
Authors: Codner Ethel , Deng Liyong , Pérez‐Bravo Francisco , Román Rossana , Lanzano Patricia , Cassorla Fernando , Chung Wendy K. 
Published: January 2006

AbstractBackgroundThe etiology of mild hyperglycemia without ketoacidosis in young children is often unknown. Maturity onset diabetes of youth (MODY) is a form of diabetes mellitus (DM) characterized by fasting hyperglycemia without evidence for autoimmune destruction of β‐cells.MethodsWe genetically analyzed four families of young children with fasting hyperglycemia with family histories of diabetes for mutations in the genes for hepatocyte nuclear factor 4 alpha (HNF4α), glucokinase (GCK), and hepatocyte nuclear factor 1 alpha (HNF1α), the genes responsible for MODY1, MODY2, and MODY3, respectively.ResultsWe identified mutations in GCK (Gly258Asp, Arg303Trp, and Arg191Gln) in three of the four families. Molecular genetic characterization in these children clarified the etiology and prognosis of the hyperglycemia and allowed discontinuation of insulin therapy in one family.ConclusionsWe conclude that molecular evaluation for MODY in children with mild fasting hyperglycemia without ketosis with family histories of diabetes can provide important prognostic information to guide therapy and exclude preclinical type 1 diabetes mellitus. Copyright © 2006 John Wiley & Sons, Ltd.
Kinetic and Theoretical Studies of a Facile, One‐Pot Preparation of a Spirocyclohexylindolinone Derivative
Authors: Sánta‐Csutor Andrea , Mucsi Zoltán , Finta Zoltán , Gönczi Csaba , Halász Judit , Csikós Éva , Hermecz István 
Published: January 2006

AbstractSpirocyclohexylindolinone is used as a moiety in drug substances. A number of synthetic methods have been suggested to introduce the cyclohexyl ring into the C(3) position of N‐protected indolinones, which complicates their preparation. A previously developed, consecutive, one‐pot, multicomponent method is studied from a mechanistic aspect. We set out to clarify the details of this mechanism and the role of the acryl ester as a reagent and a protecting group in the same flask, by using theoretical and analytical methods, in order to optimise the preparative conditions. A mechanistic energy profile of the reaction is computed at the DFT level of theory. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
How does spatial extent of fMRI datasets affect independent component analysis decomposition?
Authors: Aragri Adriana , Scarabino Tommaso , Seifritz Erich , Comani Silvia , Cirillo Sossio , Tedeschi Gioacchino , Esposito Fabrizio , Di Salle Francesco 
Published: January 2006

AbstractSpatial independent component analysis (sICA) of functional magnetic resonance imaging (fMRI) time series can generate meaningful activation maps and associated descriptive signals, which are useful to evaluate datasets of the entire brain or selected portions of it. Besides computational implications, variations in the input dataset combined with the multivariate nature of ICA may lead to different spatial or temporal readouts of brain activation phenomena. By reducing and increasing a volume of interest (VOI), we applied sICA to different datasets from real activation experiments with multislice acquisition and single or multiple sensory‐motor task‐induced blood oxygenation level‐dependent (BOLD) signal sources with different spatial and temporal structure. Using receiver operating characteristics (ROC) methodology for accuracy evaluation and multiple regression analysis as benchmark, we compared sICA decompositions of reduced and increased VOI fMRI time‐series containing auditory, motor and hemifield visual activation occurring separately or simultaneously in time. Both approaches yielded valid results; however, the results of the increased VOI approach were spatially more accurate compared to the results of the decreased VOI approach. This is consistent with the capability of sICA to take advantage of extended samples of statistical observations and suggests that sICA is more powerful with extended rather than reduced VOI datasets to delineate brain activity. Hum Brain Mapp, 2005. © 2006 Wiley‐Liss, Inc.
Simple and efficient synthesis of new chiral N,N′‐sulfonyl bis‐oxazolidin‐2‐ones
Authors: Berredjem Malika , Regainia Zine , Dewynter Georges , Montero Jean Louis , Aouf Nour‐Eddine 
Published: January 2006

AbstractA series of new chiral N,N′‐sulfonyl bis‐oxazolidin‐2‐ones were synthesized starting from 2‐aminoalcohols, sulfuryl chloride, and diethyl carbonate. This method utilizes natural amino acids as a source of chirality for the preparation of oxazolidinones. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:61–65, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20183
The reactions of hexachlorocyclotriphosphazatriene with pyridine derivatives
Authors: Begeç Saliha , Alataş Sümeyya , Kılıç Adem 
Published: January 2006

AbstractThe reactions of hexachlorocyclotripho‐sphazatriene, N3P3Cl6 (1), with 2‐hydroxypyridine (2), 2‐aminopyridine (3), 2‐amino‐6‐methyl‐pyridine (4), and 2‐hydroxy‐4‐methylquinoline (5) have been investigated. The products were identified by elemental analyses, IR, 1H, 13C, and 31P NMR spectroscopy. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:57–60, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20185
Wear and fatigue behavior of nano‐structured dental resin composites
Authors: Turssi Cecilia P. , Ferracane Jack L. , Ferracane Lucas L. 
Published: January 2006

AbstractTheoretically, nano‐structured dental resin composites are purported to have increased wear and fatigue resistance compared with microfill composites and may favor the achievement of restoratives with better long‐term performance. This study sought to assess the behavior of nano‐structured composites resulting from either abrasion and fatigue loading. Ten specimens (12 × 5 × 2.5 mm) were prepared from each of five composites: Ceram‐X mono, Filtek Supreme, Grandio, Premise, and Heliomolar (serving as the microfill control). A surface profile was recorded using a three‐dimensional profiling system, and the specimens were subjected to 105 cycles of three‐body abrasion in the new OHSU oral wear simulator. A second profile was generated and the before and after profiles were fit and analyzed. The volume loss and maximum depth of the wear facet on each specimen were calculated. Another 30 specimens (25 × 2 × 2 mm) were tested for flexural fatigue limit (FFL) in four‐point bending via the staircase method. The test was carried out until 104 cycles were completed or until fracturing the specimen. One‐way ANOVA and Tukey's test demonstrated greater volumetric loss for Grandio and Ceram‐X than that observed for the remaining composites. Kruskal‐Wallis and the least significant difference test ascertained that Heliomolar, Grandio, and Supreme showed significantly higher FFL than Ceram‐X and Premise. In terms of wear and fatigue resistance, nano‐structured composites may perform either similarly or comparatively worse than a microfilled composite. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Effect of irradiation mode on polymerization of dental composite resins
Authors: Kwon Yong Hoon , Kang Soon‐Il , Hur Bock , Park Jeong Kil , Kim Hyung‐Il 
Published: January 2006

AbstractMany researchers have sought to reduce the polymerization shrinkage in composite resins. Controlling the irradiation light seems practical because the polymerization process initiates with light by activating the photoinitiators. The present study evaluated the effect of irradiation mode on microhardness and polymerization shrinkage of composite resins. Three different irradiation modes, STD, EXP, and MED, were taken under 40‐s exposure condition. As results, the irradiation mode significantly affected the microhardness difference. However, in all products, the microhardness difference between the STD and MED modes was less than 10%. In all irradiation modes, microhardness was linearly correlated with the filler content of the tested specimens. The effect of mode on the difference of the polymerization shrinkage was not uniform even though the shrinkage values decreased following the order of the STD > EXP > MED mode. An inverse correlation was found between filler content and polymerization shrinkage in all irradiation modes and specimen thicknesses. In spite of the statistical significance of the irradiation modes on the difference of the measured values, their numeric difference was not great. Especially, compared with the STD and MED mode, the exponentially increasing light (EXP mode) produced no noticeable difference except for a delayed shrinkage process. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006