bluuebunny/crossref_metadata_2025_split huggingface dataset:
Industrial use of lipases to produce fatty acid esters
Authors: Hills Geoffrey 
Published: January 2004

AbstractA wide range of fatty acid esters can be synthesised by esterification and transesterification reactions catalysed by lipases in non‐aqueous systems. As well as modifications to the natural substrate triacylglycerol, many other commercially important substances can be produced using this enzyme technology, as lipases have been shown to have broad substrate specificities and can thus catalyse conversions with many other non‐glycerol based compounds. In mild reaction conditions, emollient esters for use in the personal care industry can be made with excellent quality.Development of economical processes was necessary to commercialise this technology for the manufacture of cosmetic ingredients. Enzymatic production methods had to be established which could compete against standard established chemical synthetic methods. Now relatively simple esters are being produced enzymatically. Extensive purification procedures to clean up products after high temperature reaction steps are not required. Product quality and specifications, such as the acid and hydroxy values of commercial ester products, could be improved. Examples of products manufactured with better purity and yields in economical and ecologically friendly processes are decyl oleate, cetyl ricinoleate, myristyl myristate and decyl cocoate.
Four Novel Nortriterpenoids Isolated from Schisandra henryi var. yunnanensis
Authors: Li Rongtao , Shen Yunheng , Xiang Wei , Sun Handong 
Published: February 2004

AbstractFour novel nortriterpenoids, henridilactones A−D (1−4), members of a very rare highly oxidized cycloartane skeletal class with a biosynthetically modified eight‐membered ring D, were isolated from the leaves and stems of Schisandra henryi var. yunnanensis. Their structures were elucidated using extensive spectroscopic techniques including 1D and 2D NMR spectra. Eight known triterpenoids were also isolated from the same source. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Pentakis(phenylethynyl)benzene and Hexakis(phenylethynyl)benzene: A Revision Concerning Two Far Too Similar Prototype Hydrocarbons
Authors: Nierle Jens , Barth Dieter , Kuck Dietmar 
Published: February 2004

AbstractA previously overlooked hydrodehalogenation reaction occurring during the multiple Pd0‐catalysed C−C coupling reaction between phenylacetylene and hexaiodo‐ and hexabromobenzene was found to give pentakis(phenylethynyl)benzene (“pentatolane”) as the major product, but no hexakis(phenylethynyl)benzene (“hexatolane”) under conditions previously claimed to yield the latter hydrocarbon. As an alternative to a viable route to hexatolane described in the literature, an independent synthesis of this hydrocarbon through sixfold Sonogashira coupling of hexakis(ethynyl)benzene with iodobenzene has been developed. Some physical and spectroscopic properties of hexatolane and of the hitherto unknown pentatolane have been determined after thorough purification by HPLC. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Thiophenylhydrazonoacetates in heterocyclic synthesis
Authors: Mohareb Rafat M. , Sherif Sherif M. , Gaber Hatem M. , Ghabrial Sami S. , Aziz Susan I. 
Published: January 2004

AbstractBenzo[b]thiophen‐2‐yl‐hydrazonoesters 4 were synthesized by coupling of 2‐diazo‐4,5,6,7‐tetrahydrobenzo[b]thiophene‐3‐carboxamide (1) with either ethyl cyanoacetate or ethyl acetoacetate. The reactivity of 4 toward a variety of nitrogen nucleophiles was investigated to yield pyrazole, isoxazole, pyrimidine, triazine, pyrazolopyridine, and pyrazolopyrimidine derivatives. © 2003 Wiley Periodicals, Inc. 15:15–20, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.hc10205
Microwave‐assisted synthesis of 2‐amino and 2‐azetidinonyl 5‐(2‐benzoyl‐phenoxymethyl) 1,3,4‐oxadiazoles
Authors: Khanum Shaukath Ara , Shashikanth S. , Sudha B. S. 
Published: January 2004

AbstractA simple high yielding method for the integration of heterocyclic rings viz. 1,3,4‐oxadiazole and azetidin‐2‐one at the benzophenone nucleus has been developed starting from substituted 2‐hydroxybenzophenones, and by using mild conditions, wet solid surface, and microwave irradiation. A comparison of this microwave‐accelerated reaction with conventional heating condition is also illustrated. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 15:37–42, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10210
Palmitoleate (=(9Z)‐Hexadeca‐9‐enoate) Esters of Oleanane Triterpenoids from the Golden Flowers of Tagetes erecta: Isolation and Autoxidation Products
Authors: Faizi Shaheen , Naz Aneela 
Published: February 2004

AbstractSix oleanane‐type triterpenoid esters were isolated from the golden flowers of Tagetes erecta. Spectral studies characterized their structures as 3‐O‐[(9Z)‐hexadec‐9‐enoyl]erythrodiol (1), 11α,12α:13β,28‐diepoxyoleanan‐3β‐yl (9Z)‐hexadec‐9‐enoate (2), 13β,28‐epoxyolean‐11‐en‐3β‐yl (9Z)‐hexadec‐9‐enoate (3), 28‐hydroxy‐11‐oxoolean‐12‐en‐3β‐yl (9Z)‐hexadec‐9‐enoate (4), 3‐O‐[(9Z‐hexadec‐9‐enoyl]‐β‐amyrin (5), and 11‐oxoolean‐12‐en‐3β‐yl (9Z)‐hexadec‐9‐enoate (6). Compounds 1–4 and 6 are new natural products, while the known 5 was isolated for the first time from the genus Tagetes, from which only one triterpenoid has earlier been obtained. Aerial oxidation (autoxidation) converted amyrin 1 into 2–4 and transformed amyrin 5 into 6. The configuration of 1–6 and an autoxidation mechanism (Scheme) involving the formation of the intermediate 11α‐hydroxyolean‐12‐ene derivatives 1b and 5b on thermal decomposition of the labile 11α‐OOH derivatives 1a and 5a, respectively, under neutral conditions are discussed. For the first time, the reactivity of the allylic HC(11) bond of triterpenoids of type 1 and 5 toward aerial oxidation was observed. The long‐chain ester group at C(3) of 1 and 5 may be responsible for their labile nature, as β‐amyrin (7), erythrodiol (8), and ursolic acid were found to be inert toward autoxidation.
Hyaluronan‐binding peptide can inhibit tumor growth by interacting with Bcl‐2
Authors: Liu Ninfei , Xu Xue‐Ming , Chen Jinguo , Wang Luping , Yang Shanmin , Underhill Charles B. , Zhang Lurong 
Published: January 2004

AbstractPrevious studies have indicated that proteins that bind hyaluronan can also inhibit the growth of tumor cells. To determine if synthetic peptides also possessed these properties, we tested a series of polypeptides containing structural motifs from different proteins for their ability to bind [3H]hyaluronan, and identified one compound termed P4 that had a particularly strong interaction. Further studies revealed that P4 also inhibited the growth of tumor cells in tissue culture as well as on the chorioallantoic membranes of chicken embryos. In addition, expression vectors for P4 caused tumor cells to grow slower in nude mice and reduced their vascularization. The P4 peptide also inhibited VEGF‐induced angiogenesis in the chorioallantoic membranes of chicken embryos. Studies on cultured cells indicated that P4 induced apoptosis, which was blocked by a pan‐caspase inhibitor. Confocal microscopy revealed that shortly after its uptake, P4 became associated with mitochondria. Immunoprecipitation indicated that P4 could bind to Bcl‐2 and Bcl‐xL, which are associated with mitochondria and regulate apoptosis. This was also supported by the fact that P4 induced the release of cytochrome c from preparations of mitochondria. Taken together, these results suggest that P4 binds to Bcl‐2 and related proteins and this activates the apoptotic cascade. © 2003 Wiley‐Liss, Inc.
Antisense abrogation of DENN expression induces apoptosis of leukemia cells in vitro, causes tumor regression in vivo and alters the transcription of genes involved in apoptosis and the cell cycle
Authors: Lim Kah M. , Yeo Wee S. , Chow Vincent T. K. 
Published: January 2004

AbstractWe previously reported that messenger RNA expression of DENN (differentially expressed in normal and neoplastic cells) is considerably higher in cancer cell lines than in normal cells. In our present study, we established that certain cancer cell lines express conspicuously higher levels of the 2 DENN isoforms in contrast to the 2 pro‐apoptotic IG20 isoforms. Antisense DENN oligodeoxynucleotide treatment of K36 cells in vitro induced extensive apoptosis, while antisense DENN silencing of K36 tumor‐bearing mice caused significant tumor regression in vivo. Compared to wild‐type murine embryonic fibroblasts, antisense treatment of NFκB and TNFR1 KO cells resulted in markedly more pronounced cell death, whereas antisense‐treated TNFα and TNFR2 knockouts exhibited less prominent apoptosis. Cell viability and apoptosis were authenticated by flow cytometry, membrane integrity, TUNEL, annexin V assays, histology and electron microscopy. Antisense abrogation of DENN expression culminated in upregulated expression of TNFR2, TRAIL and Fas, but downregulation of TNFα, TNFR1 and cyclin D3. Conversely, DENN overexpression stimulated cell proliferation and led to upregulated TRPM2 and cyclin B1, but diminished expression of Fas, TNFR2, TRAIL and Egr‐1. The participation of TNFα, TNFR1, TNFR2 and Fas in the inhibition of DENN expression was also demonstrated. These data support the anti‐apoptotic and cell survival role of DENN, especially in malignant cells, and its interaction with specific genes and proteins involved in the apoptotic and cell cycle pathways. © 2003 Wiley‐Liss, Inc.
Candidate regions of tumor suppressor locus on chromosome 9q31.1 in gastric cancer
Authors: Kakinuma Naoto , Kohu Kazuyoshi , Sato Masaaki , Yamada Tatsuya , Nakajima Motowo , Akiyama Tetsu , Ohwada Susumu , Shibanaka Yasuhiko 
Published: January 2004

AbstractLoss of heterozygosity (LOH) is an important event of tumorigenesis. In gastric cancer, we found a novel region of LOH in chromosome 9q having about 800 kb deletions at 9q31.1. The microsatellite marker D9S938 in that region exhibiting the highest LOH frequency, 56.5%. In addition, the LOH at 9q31.1 did not show any relationship to either histologic types or stages of gastric cancers, and several genes were predicted in the remaining allele by in silico methods. These data suggest that the deletion at 9q31.1 would be common in both differentiated‐type and undifferentiated‐type gastric cancers. Furthermore, this deletion was found in the primary tumors of early‐stage gastric cancer, indicating that loss of function of predicted genes appears to be associated with the tumorigenesis of gastric cancer. © 2003 Wiley‐Liss, Inc.
Expression of uteroglobin in normal and carcinogenic endometrium and influence of hormone replacement therapy
Authors: Tanaka Ryoichi , Saito Tsuyoshi , Shijubo Noriharu , Takehara Masaki , Yamada Gen , Kawabata Isao , Itoh Yoshihisa , Kudo Ryuichi 
Published: January 2004

AbstractUteroglobin, first reported in 1968 as a steroid secreted in rabbit uterine fluid during early pregnancy, is a progesterone‐regulated and progesterone‐binding protein. There is evidence that indicates that uteroglobin is inversely correlated to neoplastic growth but its role to endometrial carcinogenesis is not known. Therefore we analyzed the expression of uteroglobin in 13 normal endometrium, 19 hyperplasia and 21 endometrial carcinoma samples and the relation to estrogen receptor‐α (ER‐α) and progesterone receptor (PR) by immunohistochemistry and Western blotting. We also analyzed the expression of uteroglobin in 15 menopausal women who received hormone replacement therapy (HRT). The expression of uteroglobin was higher during the secretory phase than in the proliferative phase; however, it was detected in endometrial hyperplasia as weakly as in the proliferative phase and decreased according to the loss of differentiation in endometrial carcinoma. The results were basically in accord with those for PR; however, the expression of uteroglobin was weak, though PR was most detected in endometrial hyperplasia. In menopausal endometrium, the group treated with estrogen plus progesterone exhibited higher expression of uteroglobin than the group treated only with estrogen. The evidence suggests that uteroglobin expression is regulated by progesterone in the normal endometrium but that the regulation by PR is lost in endometrial hyperplasia and carcinoma according to acquirement of tumorigenesis and that estrogen plus progesterone therapy reduces the risk for endometrial carcinoma by restoring uteroglobin. © 2003 Wiley‐Liss, Inc.
A kinematic view of loop closure
Authors: Coutsias Evangelos A. , Seok Chaok , Jacobson Matthew P. , Dill Ken A. 
Published: January 2004

AbstractWe consider the problem of loop closure, i.e., of finding the ensemble of possible backbone structures of a chain segment of a protein molecule that is geometrically consistent with preceding and following parts of the chain whose structures are given. We reduce this problem of determining the loop conformations of six torsions to finding the real roots of a 16th degree polynomial in one variable, based on the robotics literature on the kinematics of the equivalent rotator linkage in the most general case of oblique rotators. We provide a simple intuitive view and derivation of the polynomial for the case in which each of the three pair of torsional axes has a common point. Our method generalizes previous work on analytical loop closure in that the torsion angles need not be consecutive, and any rigid intervening segments are allowed between the free torsions. Our approach also allows for a small degree of flexibility in the bond angles and the peptide torsion angles; this substantially enlarges the space of solvable configurations as is demonstrated by an application of the method to the modeling of cyclic pentapeptides. We give further applications to two important problems. First, we show that this analytical loop closure algorithm can be efficiently combined with an existing loop‐construction algorithm to sample loops longer than three residues. Second, we show that Monte Carlo minimization is made severalfold more efficient by employing the local moves generated by the loop closure algorithm, when applied to the global minimization of an eight‐residue loop. Our loop closure algorithm is freely available at http://dillgroup. ucsf.edu/loop_closure/. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 510–528, 2004
Implementing a community intervention to reduce young people's risks for getting HIV: Unraveling the complexities
Authors: Visser Maretha J. , Schoeman Johan B. 
Published: February 2004

AbstractThe ineffectiveness of community‐based interventions can often be traced to problems that occur during implementation. In this study, we outline the implementation of a human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) prevention program in an educational setting in South Africa. An action research approach was used in the implementation of the intervention and a process and outcome evaluation, integrating qualitative and quantitative research methods, was made. The research illustrated the various levels of interaction in the community and the complexity of the processes involved in the implementation of interventions to facilitate community change. Social ecological theory, systems theory, and the social constructional approach are used to clarify the complexities of the implementation of community interventions. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 145–165, 2004.
Extracellular chitinase production by Trichoderma harzianum in submerged fermentation
Authors: Sandhya C. , Adapa Leela Krishna , Nampoothiri K. Madhavan , Binod P. , Szakacs George , Pandey Ashok 
Published: February 2004

AbstractExtra‐cellular chitinase production by a chitinolytic fungus Trichoderma harzianum TUBF 966 using submerged fermentation was studied. Colloidal chitin (1.5% w/v) was used as sole carbon source. Maximum chitinase production (14.7 U/ml) was obtained when fermentation was carried out at 30 °C for 96 h using 72 h old mycelium in a medium containing colloidal chitin 1.5% (w/v) as carbon source and 0.42 (% w/v) peptone as nitrogen source (pH 5.5). Supplementation of additional carbon sources (0.75% w/v) showed no further enhancement in chitinase production while supplementation of nitrogen sources (0.42% w/v) such as peptone and tryptone in the fermentation medium showed a marked increase in production. The process parameters that controlled chitinase production by the fungus were studied and presented here.
Differential effects of organic modifiers on the enantioseparation of dimetindene maleate with carboxymethyl‐β‐cyclodextrin in capillary electrophoresis
Authors: Van Eeckhaut Ann , Detaevernier Marc Robert , Crommen Jacques , Michotte Yvette 
Published: January 2004

AbstractMethanol enhances the enantioresolution of dimetindene enantiomers with carboxymethyl‐β‐cyclodextrin (CMCD) as chiral selector at a concentration below its optimal value. The same effect was observed with ethanol (EtOH), although less pronounced. On the other hand, the addition of isopropanol (IP) or acetonitrile (ACN) decreases the enantioseparation. To elucidate the underlying mechanisms of these observed effects, other neutral (β‐CD, hydroxypropyl‐β‐CD, and trimethyl‐β‐CD) as well as chargeable (carboxyethyl‐β‐CD and succinyl‐β‐CD) CD derivatives were also tested with MeOH as organic modifier. It can be concluded that the increased enantioresolution of dimetindene enantiomers was only noted with CMCD as chiral selector and a short‐chain organic modifier containing an alcohol function. The slight deprotonation of CMCD at pH 3.0 was only partly responsible for the high enantioselectivity and the ‘favourable’ effect of MeOH or EtOH. An important feature that can be concluded from these results is that for this particular analyte approximately the same resolution can be obtained with a lower CMCD concentration and the addition of some MeOH, compared to a MeOH free buffer.
Development of a Capillary Zone Electrophoretic method to determine six antidepressants in their pharmaceutical preparations. Experimental design for evaluating the ruggedness of method
Authors: Rodríguez Flores Juana , Berzas Nevado Juan J. , Contento Salcedo Ana M. , Cabello Díaz Maria P. 
Published: January 2004

AbstractA capillary zone electrophoresis method is proposed for the separation of six of the antidepressants most used for the treatment of mental illness (clomipramine, paroxetine, fluoxetine, citalopram, fluvoxamine, and trazodone). Optimum conditions for their separation were investigated. A background electrolyte solution consisting of 50 mM phosphate buffer adjusted to pH 2.0, hydrodynamic injection, and 25 kV as separation voltage were used. Relative standard deviations (RSD) were <0.38% and <2.93% for migration time and corrected peak area (n = 24), respectively. Detection limits obtained for the six antidepressants ranged from 0.03 to 0.11 mg L–1. Stability of the solutions, linear concentration range, accuracy, and precision were examined during validation of the method. A ruggedness test of this method was performed using the fractional factorial model of Plackett‐Burman, requiring in our case design of a matrix of 15 experiments, in which the influence of seven factors at three different levels was tested on different electrophoretic results: efficiency; resolution; and corrected peak area. Statistical evaluation of electrophoretic results was achieved by Youden and Steiner's method. The described method is rapid, sensitive, and rugged and it was tested for the pharmaceutical formulation analysis, giving recoveries between 95.6 and 99.1% with respect to the nominal content
Simultaneous determination of tretinoin and clindamycin phosphate and their degradation products in topical formulations by reverse phase HPLC
Authors: Ye Yuerong Rose , Bektic Edin , Buchta Richard , Houlden Robert , Hunt Barry 
Published: January 2004

AbstractA new HPLC method based on reverse phase separation and photodiode‐array detection has been developed for the simultaneous determination of tretinoin and clindamycin phosphate, and their degradation products in topical formulations. The method has been shown to be stability indicating, accurate, and precise for two different formulation vehicles. Separation was achieved on a reverse phase C18 column (Lichrospher, RP18, 5 μm, 25 cm×4.6 mm ID, Phenomenex, USA) using a simple gradient with aqueous‐acetonitrile and aqueous‐methanol mobile phases. The method recovery averaged 100.3% for tretinoin and 99.6% for clindamycin phosphate at a concentration range between 80% and 120% of the label claim. The method can be applied to assess the stability of tretinoin and clindamycin phosphate in pharmaceutical formulations containing tretinoin and clindamycin phosphate individually or in combination as active drugs.
Elution and preliminary structure‐retention modeling of polar and ionic substances in supercritical fluid chromatography using volatile ammonium salts as mobile phase additives
Authors: Pinkston J. David , Stanton David T. , Wen Dong 
Published: January 2004

AbstractSupercritical fluid chromatography has primarily been applied to relatively nonpolar analytes, even when polar organic solvents are used as modifiers. Here, we show that low levels of volatile ammonium salts as mobile‐phase additives allow the elution of polar and even ionic organic materials such as sulfonate salts, carboxylate salts, polyamines, and quaternary ammonium salts. Also, volatile ammonium salts are compatible with mass spectrometric detection, in contrast to other common additives. We have performed preliminary structure‐activity‐relationship modeling for retention in the CO2/methanol/NH4OAc/Deltabond Cyano system. We have developed a three‐descriptor model, where one descriptor, the “relative negative charged surface” explains over 61% of the variance in the retention values. We suggest that two mechanisms have the greatest influence on retention in this system. One is related to the presence of a volatile ammonium salt, the other is related to the ability of a molecule to “hide” its atom with the greatest partial negative charge.
Elektrochemische Korrosionsuntersuchungen an der Magnesiumlegierung AZ91: Beschreibung kritischer Parameter und deren Einfluss auf die Angriffsmechanismen auf NRC‐Proben
Authors: Lips K. , Schmutz P. , Heer M. , Uggowitzer P. J. , Virtanen S. 
Published: January 2004

AbstractAufgrund des zunehmenden Einsatzes von Magnesiumlegierungen als Strukturwerkstoff in Leichtbauanwendungen erlangen deren Korrosionseigenschaften erhöhte Beachtung. In dieser Arbeit werden wichtige Parameter, die zur Korrosion der Magnesiumlegierungen führen, untersucht und diskutiert. Es wird gezeigt, dass der pH‐Wert in einer Lösung bis zu Werten über 11 ansteigt, die in Kontakt mit Magnesium oder AZ91 steht. Die Lösungsmenge und der Oberflächenzustand des Metalles spielen dabei im Gegensatz zum Chloridgehalt eine wichtige Rolle. Elektrochemische Messungen machen klar, dass sich erst bei einem pH‐Wert von 12 eine stabile Oberflächenschicht bildet. Aggressive Chloridionen können diese Hydroxidschicht lokal zerstören, woraufhin eine Repassivierung stattfinden kann. Bei pH 11 fehlt dem Oberflächenfilm die Stabilität und es kommt zur lokalen Auflösung, so dass die Chloridionen eine geringe Rolle in der Initiierung der Korrosion spielen. Um eine höhere Stabilität zu erreichen, können Inhibitoren eingesetzt werden. Chromat wird in die Hydroxidschicht eingebaut und verleiht ihr so die nötige Stabilität bei pH 11. NRC‐Bauteile (New Rheocasting) zeichnen sich aus durch ausgezeichnete mechanische Eigenschaften, doch kommt es wegen der speziellen Phasenverteilung vermehrt zu einer galvanischen Kopplung, weswegen sich die Korrosionsanfälligkeit erhöht. Langsam abgekühlte AZ91 Proben unterscheiden sich im Gefüge von den NRC‐Proben und zeigen auch ein anderes Verhalten in der Initiierungsphase der Korrosion.