bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two Methods for the Determination of Enantiomeric Excess and Concentration of a Chiral Sample with a Single Spectroscopic Measurement
Authors: Zhu Lei , Shabbir Shagufta H. , Anslyn Eric V. 
Published: October 2006

AbstractThe previously established enantioselective indicator–displacement assays (eIDAs) for the determination of concentration and enantiomeric excess (ee) require two spectroscopic measurements for each chiral sample. To further simplify the operation of eIDAs, we now introduce two innovative analytical methods, both of which utilize a dual‐chamber quartz cuvette, which reduces the number of spectroscopic measurements from two to one. An attractive feature of this cuvette is that the concentration‐ and ee‐dependent absorption data can be collected at the isosbestic points or transparent regions of the spectra recorded in each individual chamber, thereby reflecting optical changes that occur in the other chamber. Therefore, two independent equations, which are needed to solve the values of the two independent variables—concentration and ee—can be established with only a single spectroscopic measurement. The first method takes advantage of this feature in conjunction with a judicious choice of indicator/host combinations to generate concentration‐ and ee‐dependent calibration curves. Our second method removes the requirement to measure equilibrium constants and molar absorptivities altogether through the use of artificial neural networks (ANNs). The most frequently used three‐layer feed‐forward network is generated, which relates the absorption data to concentration and ee of the samples by training with a back propagation procedure. Here, the data collection is not limited to the isosbestic points or transparent regions. Both approaches enabled accurate and rapid determination of concentration and ee of chiral samples. The technology removes the relative difficulty, which is the need for two separate measurements for concentration and ee respectively, of analyzing chiral samples compared to achiral samples. When implemented in a high‐throughput format, this technology should greatly facilitate the discovery of asymmetric catalysts in the same way as conventional high‐throughput screening assays.
Accuracy of lymphatic mapping and sentinel lymph node biopsy after previous wide local excision in patients with primary melanoma
Authors: Gannon Christopher J. , Rousseau Dennis L. , Ross Merrick I. , Johnson Marcella M. , Lee Jeffrey E. , Mansfield Paul F. , Cormier Janice N. , Prieto Victor G. , Gershenwald Jeffrey E. 
Published: October 2006

AbstractBACKGROUND.Sentinel lymph node (SLN) status is the most important prognostic factor with respect to the survival of patients with primary cutaneous melanoma. However, lymphatic mapping and SLN biopsies (LM/SLNBs) performed in patients who have had a wide local excision (WLE) may not accurately reflect the pathologic status of the draining lymph node basins. The purpose of this study was to assess the feasibility and accuracy of LM/SLNB in patients who have had a previous WLE.METHODS.A single‐institution database was examined to identify patients who had a WLE before LM/SLNB and patients who had a concomitant LM/SLNB. Primary clinicopathologic features (age, tumor thickness, and ulceration), SLN identification rate, SLN pathologic status, and the incidence and sites of recurrences were compared between patients with and without prior WLE.RESULTS.Of the 1395 patients identified, 104 had WLE before LM/SLNB. The mean preoperative WLE radial margin was 1.4 cm (median, 1.0 cm). LM/SLNB was successful in 103 of 104 (99%) patients. Age, tumor thickness, incidence of ulceration, and incidence of SLN positivity in the group with prior WLE were similar to those of the cohort of patients who had concomitant LM/SLNB and WLE (n = 1291). In 97 (93%) of the 104 prior‐WLE patients, the surgical defects were closed by either primary closure or skin graft; 7 patients (7%) had rotational flaps. The median follow‐up of these 104 patients was 51 months. Among the prior‐WLE group, 19 patients (18%) had a positive SLNB; of these 19 patients, 4 (21%) had recurrences (3 distant failures and 1 local and distant failure). There were no lymph node recurrences—in a mapped or unmapped basin—in these 104 patients with a negative or positive SLNB.CONCLUSIONS.SLNs can be successfully identified and accurately reflect the status of the regional lymph node basin in carefully selected melanoma patients with a previous WLE. Prior WLE does not appear to adversely impact the ability to detect lymphatic metastases, although the utility of LM/SLNB in patients who have undergone extensive reconstruction of the primary excision site remains to be defined. Because more extensive surgery may be required to accomplish accurate lymph node staging in patients who have undergone prior WLE—including the possible removal of SLNs from additional lymph node basins and an additional surgical procedure—to minimize morbidity and cost, concomitant WLE and LM/SLNB is strongly preferred whenever possible. Cancer 2006. © 2006 American Cancer Society.
Simultaneous quantification of oxidative stress and cell spreading using 5‐(and‐6)‐chloromethyl‐2′,7′‐dichlorofluorescein
Authors: Koopman Werner J. H. , Verkaart Sjoerd , van Emst‐de Vries Sjenet E. , Grefte Sander , Smeitink Jan A. M. , Willems Peter H. G. M. 
Published: October 2006

AbstractBackground:Mitochondrial dysfunction may lead to increased oxidative stress and consequent changes in cell spreading. Here, we describe and validate a novel method for simultaneous quantification of these two parameters.Methods:Human skin fibroblasts were loaded with 5‐(and‐6)‐chloromethyl‐2′,7′‐dichlorodihydrofluorescein (CM‐H2DCF), and its oxidative conversion into CM‐DCF was monitored as a function of time by video‐rate confocal microscopy and real‐time image averaging. Cell size was determined after binarization of the acquired images.Results:At the lowest practical laser output, CM‐DCF formation occurred with zero order kinetics, indicating that [CM‐H2DCF] was not rate‐limiting and that the rate of [CM‐DCF] formation (VCM‐DCF) was a function of the cellular oxidant level. Analysis of fibroblasts of a healthy control subject and a patient with a deficiency of NADH:ubiquinone oxidoreductase, the first complex of the oxidative phosphorylation system, revealed a significant increase in cellular oxidant level in the latter cells that was, however, not accompanied by a change in cell spreading. Conversely, chronic treatment with 6‐hydroxy‐2,5,7,8‐tetramethylchroman‐2‐carboxylic acid (Trolox), a derivative of vitamin E, markedly decreased the oxidant level and cell spreading in both control and patient fibroblasts.Conclusions:We present a reliable method for simultaneous quantification of oxidant levels and cell spreading in living cells. © 2006 International Society for Analytical Cytology
Parameter identification of framed structures using an improved finite element model‐updating method—Part II: application to experimental data
Authors: Yu Eunjong , Wallace John W. , Taciroglu Ertugrul 
Published: October 2006

AbstractIn this study, we determine an updated finite element model of a reinforced concrete building—which was damaged from shaking during 1994 Northridge earthquake—using forced‐vibration test data and a novel model‐updating technique. Developed and verified in the companion paper (viz. BVLSrc, Earthquake Eng. Struct. Dyn. 2006; this issue), this iterative technique incorporates novel sensitivity‐based relative constraints to avoid ill conditioning that results from spatial incompleteness of measured data. We used frequency response functions and natural frequencies as input for the model‐updating problem. These data were extracted from measurements obtained during a white‐noise excitation applied at the roof of the building using a linear inertial shaker. Flexural stiffness values of properly grouped structural members, modal damping ratios, and translational and rotational mass values were chosen as the updating parameters, so that the converged results had direct physical interpretations, and thus, comparisons with common parameters used in seismic design and evaluation of buildings could be made. We investigated the veracity of the updated finite element model by comparing the predicted and measured dynamic responses under a second, and different type of forced (sine‐sweep) vibration, test. These results indicate that the updated model replicates the dynamic behaviour of the building reasonably well. Furthermore, the updated stiffness factors appear to be well correlated with the observed building damage patterns (i.e. their location and severity). Copyright © 2006 John Wiley & Sons, Ltd.
Modelling thermal degradation of composite materials
Authors: Trelles Javier , Lattimer Brian Y. 
Published: October 2006

AbstractA one–dimensional, transient thermal degradation heat transfer model for the response of composite materials when exposed to fire is presented. The model can handle layers of different materials. Material properties are functions of temperature. The reaction can be specified using Arrhenius‐type parameters or by inputting a density–temperature relationship determined by any experimental technique such as thermogravimetric analysis. The model is validated against the experimental data presented in Boyer's 1984 dissertation. Overall, the model provides excellent agreement with the experimental data. It is shown that very little difference is found between results arrived at by Arrhenius kinetics and results obtained by specifying the easier to measure density–temperature relationship. From this it is concluded that this technique is a viable alternative to Arrhenius‐type models. Copyright © 2006 John Wiley & Sons, Ltd.
Numerical simulation of turbulent impinging jet on a rotating disk
Authors: Abdel‐Fattah A. 
Published: October 2006

AbstractThe calculations of quasi‐three‐dimensional momentum equations were carried out to study the influence of wall rotation on the characteristics of an impinging jet. The pressure coefficient, the mean velocity distributions and the components of Reynolds stress are calculated. The flow is assumed to be steady, incompressible and turbulent. The finite volume scheme is used to solve the continuity equation, momentum equations and k–ε model equations. The flow characteristics were studied by varying rotation speed ω for 0⩽ω⩽167.6 rad/s, the distance from nozzle to disk (H/d) was (3, 5, 8 and 10) and the Reynolds number Re base on VJ and d was 1.45 × 104. The results showed that, the radial velocity and turbulence intensity increase by increasing the rotation speed and decrease in the impingement zone as nozzle to disk spacing increases. When the centrifugal force increases, the radial normal stresses and shear stresses increase. The location of maximum radial velocity decreases as the local velocity ratio (α) increases. The pressure coefficient depends on the centrifugal force and it decreases as the distance from nozzle to plate increases. In impingement zone and radial wall jet, the spread of flow increases as the angular velocity decreases The numerical results give good agreement with the experiment data of Minagawa and Obi (Int. J. of Heat and Fluid Flow 2004; 25:759–766). Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis of some novel imidazolidine derivatives and their metal complexes with biological and antitumor activity
Authors: Al‐Raqa Shaya Y. , ElSharief Ahmed M. Sh. , Khalil Saied M. E. , Al‐Amri Abdulkhaliq M. 
Published: October 2006

AbstractHalogenated imidazo(pyrazine,[1,4]diazocine and quinoxaline), 9,10‐anthraquinone‐ [6,7‐e], phenanthroline[5,6‐e] {imidazo[4,5‐b]pyrazine}, and naphtho[1,8‐ef]imidazo[4,5‐b][1,4] diazipen were obtained through interaction of imidazolidineiminothiones with the corresponding diamino compounds. Imidazo[4,5‐e] triazine and pyrrolo[2,3‐d]imidazole were prepared when the iminothiones were reacted with thiocarbohydrazide and with ethylphenyl acetate, separately. Some of the synthesized compounds exhibited better biological and antitumor activities. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:634–647, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20244
Radical 4‐exo Cyclizations onto O‐Alkyloxime Acceptors: Towards the Synthesis of Penicillin‐Containing Antibiotics
Authors: Scanlan Eoin M. , Walton John C. 
Published: October 2006

AbstractThe 4‐exo cyclizations of two types of carbamoyl radicals onto O‐alkyloxime acceptor groups were studied as potential routes to 3‐amino‐substituted azetidinones and hence to penicillins. A general synthetic route to ‘benzaldehyde oxime oxalate amides’ (= 2‐[(benzylideneamino)oxy]‐2‐oxoacetamides; see, e.g., 10c) of 2‐{[(benzyloxy)imino]methyl}‐substituted thiazolidine‐4‐carboxylic acid methyl esters 9 was developed (Scheme 3). It was shown by EPR spectroscopy that these compounds underwent sensitized photodissociation to the corresponding carbamoyl radicals but that these did not ring close. An analogous open‐chain precursor, benzaldehyde O‐(benzylaminoacetaldehyde‐O‐benzyloxalyl)oxime, 15, lacking the 5‐membered thiazolidine ring, was shown by EPR spectroscopy to release the corresponding carbamoyl radical (Scheme 4). The latter underwent 4‐exo cyclization onto its CNOBn bond in non‐H‐atom donor solvents. The rate constant for this cyclization was determined by the steady‐state EPR method. Spectroscopic evidence indicated that the reverse ring‐opening process was slower than cyclization.
Deriving evolutionary tree models of the oncogenesis of endometrial adenocarcinoma
Authors: Chen Lei , Nordlander Carola , Behboudi Afrouz , Olsson Björn , Levan Karin Klinga 
Published: October 2006

AbstractEndometrial adenocarcinoma (EAC) is the fourth leading cause of cancer death in women worldwide, but not much is known about the underlying genetic factors involved in the development of this complex disease. In the present work, we used 3 different algorithms to derive tree models of EAC oncogenesis from data on the frequencies of genomic alterations in rat chromosome 10 (RNO10). The tumor material was derived from progenies of crosses between the EAC susceptible BDII inbred rat strain and two non susceptible inbred rat strains. Data from allelic imbalance scans of RNO10 with microsatellite markers on solid tumor material and corresponding tissue cultures were used. For the analysis, RNO10 was divided into 24 segments containing a total of 59 informative microsatellite markers. The derived tree models show that genomic alterations have occurred in 11 of the 24 segments. In addition, the models provide information about the likely order of the alterations as well as their relationship with each other. Interestingly, there was a high degree of consistency among the different tree models and with the results of previous studies, which supports the reliability of the tree models. Our results may be extended into a general approach for tree modeling of whole genome alterations during oncogenesis. © 2006 Wiley‐Liss, Inc.
Mammalian peroxidases activate anticancer drug ellipticine to intermediates forming deoxyguanosine adducts in DNA identical to those found in vivo and generated from 12‐hydroxyellipticine and 13‐hydroxyellipticine
Authors: Stiborová Marie , Poljaková Jitka , Ryšlavá Helena , Dračínský Martin , Eckschlager Tomáš , Frei Eva 
Published: October 2006

AbstractEllipticine is a potent antineoplastic agent, whose mode of action is considered to be based mainly on DNA intercalation, inhibition of topoisomerase II and cytochrome P450‐mediated formation of covalent DNA adducts. This is the first report on the molecular mechanism of ellipticine oxidation by peroxidases (human myeloperoxidase, human and ovine cyclooxygenases, bovine lactoperoxidase, horseradish peroxidase) to species forming ellipticine‐DNA adducts. Using NMR spectroscopy, the structures of 2 ellipticine metabolites were identified; the major product is the ellipticine dimer, in which the 2 ellipticine skeletons are connected via N6 of the pyrrole ring of one ellipticine molecule and C9 in the second one. The minor metabolite is ellipticine N2‐oxide. Using 32P‐postlabeling and [3H]‐labeled ellipticine, we showed that ellipticine binds covalently to DNA after its activation by peroxidases. The DNA adduct pattern induced by ellipticine consisted of a cluster of up to 4 adducts. The 2 adducts are indistinguishable from the 2 major adducts generated between deoxyguanosine in DNA and either 13‐hydroxy‐ or 12‐hydroxyellipticine or in rats treated with ellipticine, or if ellipticine was activated with human hepatic and renal microsomes. The results presented here are the first characterization of the peroxidase‐mediated oxidative metabolites of ellipticine and we have proposed species, 2 carbenium ions, ellipticine‐13‐ylium and ellipticine‐12‐ylium, as reactive species generating 2 major DNA adducts seen in vivo in rats treated with ellipticine. The study forms the basis to further predict the susceptibility of human cancers to ellipticine. © 2006 Wiley‐Liss, Inc.
Body size in relation to cancer of the uterine corpus in 1 million Norwegian women
Authors: Bjørge Tone , Engeland Anders , Tretli Steinar , Weiderpass Elisabete 
Published: October 2006

AbstractA positive association between overweight/obesity and endometrial cancer has been observed. It has been hypothesized that obesity is mostly associated with a subtype described as estrogen‐dependent (Type I tumors), constituting about 80% of the endometrial tumors. Few epidemiologic studies have, however, analyzed different histological subtypes separately. The present study aimed at exploring the relations between body size and histological subtypes of cancer of the uterine corpus. Height and weight were measured in over 1 million Norwegian women aged 20–74 during 1963–2001. During follow‐up, 9,227 cancers of the uterine corpus were diagnosed. The tumors were classified as Type I tumors (mostly endometrial adenocarcinomas with subgroups), Type II tumors (papillary, serous, and clear cell adenocarcinomas and some poorly differentiated carcinomas), sarcomas, and mixed tumors. Relative risks (RRs) of cancer of the uterine corpus were estimated using Cox proportional hazards regression. Compared with women with normal BMI, overweight and obese women had an overall RR of cancer of the uterine corpus of 1.36 (95% CI: 1.29–1.42) and 2.51 (95% CI: 2.83–2.66). The increase in risk was most pronounced for Type I tumors, but was also seen for Type II tumors, sarcomas and mixed tumors. The overall RR of corpus uteri cancer associated with a 10‐cm increase in height was 1.09 (95% CI: 1.05–1.13), and was mostly observed for Type I tumors. © 2006 Wiley‐Liss, Inc.
5α‐Reductase type 1 and aromatase in breast carcinoma as regulators of in situ androgen production
Authors: Suzuki Takashi , Miki Yasuhiro , Moriya Takuya , Akahira Jun‐ichi , Ishida Takanori , Hirakawa Hisashi , Yamaguchi Yuri , Hayashi Shin‐ichi , Sasano Hironobu 
Published: October 2006

AbstractPrevious in vitro studies demonstrated that bioactive androgen 5α‐dihydrotestosterone (DHT) exerted antiproliferative effects through an interaction with androgen receptor (AR) in breast carcinoma cells. However, AR status has not been examined in association with DHT concentration in breast carcinoma tissues, and significance of androgenic actions remains unclear in breast carcinomas. Therefore, in our study, we first examined intratumoral DHT concentrations in 38 breast carcinoma tissues using liquid chromatography/electrospray tandem mass spectrometry. Intratumoral DHT concentration was positively associated with 5α‐reductase type 1 (5αRed1), and negatively correlated with aromatase. We then examined clinical significance of AR and 5αRed1 status in 115 breast carcinoma tissues by immunohistochemistry. Breast carcinomas positive for both AR and 5αRed1 were inversely associated with tumor size or Ki‐67. These patients showed significant associations with a decreased risk of recurrence and improved prognosis for overall survival, and the AR / 5αRed1 status was demonstrated an independent prognostic factor. Moreover, we examined possible regulation of DHT production by aromatase in in vitro studies. DHT synthesis from androstenedione in MCF‐7 cells was significantly inhibited by coculture with aromatase‐positive stromal cells, which was significantly reversed by addition of aromatase inhibitor exemestane. These results suggest that intratumoral DHT concentration is mainly determined by 5αRed1 and aromatase in breast carcinoma tissues, and antiproliferative effect of DHT may primarily occur in the cases positive for both AR and 5αRed1. Aromatase inhibitors may be more effective in these patients, possibly due to increasing local DHT concentration with estrogen deprivation. © 2006 Wiley‐Liss, Inc.
Effect of fish oil supplementation for 2 generations on changes in macrophage function induced by Walker 256 cancer cachexia in rats
Authors: Folador Alessandra , Hirabara Sandro M. , Bonatto Sandro J.R. , Aikawa Júlia , Yamazaki Ricardo K. , Curi Rui , Fernandes Luiz C. 
Published: October 2006

AbstractThe effect of coconut fat (rich in medium saturated fatty acids) or fish oil (rich in ω‐3 polyunsaturated fatty acids) supplementation for 2 generations on tumor growth, cancer cachexia, animal survival and macrophage function was investigated in Walker 256 tumor‐bearing rats. Female Wistar rats were supplemented with coconut fat or fish oil prior to mating and then throughout pregnancy and gestation. Both supplementations were daily and orally given at 1 g per kg body weight as a single bolus. Same treatment was performed by the 2 following generations. At 90 days of age, male offspring (50%) from F2 generation were subcutaneously inoculated with 2 × 107 Walker 256 tumor cells. At 14 days after tumor implantation, rats not supplemented displayed cancer cachexia characterized by loss of body weight, hypoglycemia, hyperlacticidemia, hypertriglyceridemia, decreased food intake and depletion of glycogen stores in the liver and skeletal muscles. Supplementation with coconut fat did not affect these parameters. However, supplementation with fish oil decreased tumor growth (59%), prevented body weight loss and food intake reduction and attenuated cancer cachexia. In addition, fish oil increased animal survival up to 20 days (from 25% in rats not supplemented to 67% in rats supplemented with fish oil) and improved macrophage function characterized by increased phagocytosis capacity and production of hydrogen peroxide and nitric oxide. These results suggest that fish oil supplementation for 2 generations improves macrophage function in association to reduced tumor growth and attenuated cancer cachexia, maintaining food intake and increasing animal survival. © 2006 Wiley‐Liss, Inc.