bluuebunny/crossref_metadata_2025_split huggingface dataset:
Brother versus brother: competitive stabilization of carbocationic centers by flanking cyclopropanes and π‐systems
Authors: Siebert Matthew R. , Tantillo Dean J. 
Published: April 2007

AbstractB3LYP and MP2 quantum chemical calculations on cyclopropylcarbinyl cations fused to various cyclic and polycyclic architectures are described. ‘Competition’ for delocalization between the cyclopropane and other cyclopropanes and/or π‐systems incorporated into the (poly)cyclic framework to which it is fused was assessed, primarily through the use of characteristic geometric perturbations to the cyclopropane substructure. For example, a linear correlation between the orientation of the ‘empty p‐orbital’ at the carbocationic center, which is affected by the nature of the (poly)cyclic framework, and the magnitude of bond elongation in the cyclopropane was observed. Possible bis‐ and trishomoaromaticity of some systems was also evaluated using nucleus independent chemical shift (NICS) and magnetic susceptibility exaltation calculations. Copyright © 2007 John Wiley & Sons, Ltd.
Physical image vs structure relation: part 12 – structure of 2,2,5,5‐tetramethyl‐dihydro‐furan‐3‐one oxime and its protonated forms through isomerization and NMR spectra
Authors: Nazarski Ryszard B. 
Published: April 2007

AbstractThe study of an isomeric A/B mixture of the title oxime 1, by photolytic or thermal E,Z‐isomerization and NMR measurement including 1H{1H}‐NOE difference spectra, led to assignment of the E configuration to its predominating form A. The 1H/13C data were interpreted in terms of steric overcrowding of both forms, especially of the thermolabile photoproduct B. Four classical (empirical) NMR methods of elucidating the oxime geometry were critically tested on these results. Unexpected vapor‐phase photoconversion A→B in the window glass‐filtered solar UV and spectroscopic findings on their protonated states were discussed, as well. The kinetically controlled formation of the N‐protonated species (Z)‐5+ was proved experimentally. In addition, some 1H NMR assignments reported for structurally similar systems were rationalized (3 and 4) or revised (1 and 7–9) with the GIAO‐DFT(B3LYP) and/or GIAO‐HF calculational results. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and photochromism of 1,2‐dicyano[2.n]metacyclophan‐1‐enes
Authors: Takeshita Michinori , Inoue Masako , Hisasue Hideki , Maekawa Syun , Nakamura Takeshi 
Published: April 2007

AbstractSyntheses and photochromic properties of 1,2‐dicyano[2.n]metacyclophan‐1‐enes are described. Dicyanometacyclophan‐1‐enes have been prepared by novel intramolecular coupling reaction of 1,n‐bis[(cyanomethyl)phenyl]alkanes in the presence of phase transfer catalyst. The photocyclization reaction of the prepared metacyclophan‐1‐enes took place upon irradiation with UV light and the pale yellow solution turned to violet due to the formation of the closed forms. The spectra and the color of the solutions returned to the initial states by the visible irradiation. The lifetimes of the closed forms were dependent on the chain length (n). As the chain length is shorter, the lifetime becomes longer. This is due to the steric energy of metacyclophan‐1‐ene. Hence, it becomes possible to control the thermal stability of the photoisomer by the change of chain length (n). The quantum yield for photocyclization reaction is the highest among 1,2‐dicyanodiarylethene family, since the conformation of the metacyclophan‐1‐ene is fixed to the photoactive form. Synthesis and photochromic properties of 1,2‐ dicyano[2.n]metacyclophan‐1‐enes bearing various kinds of substituents are also described. Copyright © 2007 John Wiley & Sons, Ltd.
ABA‐type amphiphilic triblock copolymers containing p‐ethoxy azobenzene via atom transfer radical polymerization: Synthesis, characterization, and properties
Authors: Tang Xinde , Gao Longcheng , Fan Xinghe , Zhou Qifeng 
Published: April 2007

AbstractABA‐type amphiphilic triblock copolymers composed of poly(ethylene glycol)s (PEGs) with different number‐average molecular weights as the hydrophilic blocks (B) and poly{6‐[4‐(4‐ethoxyphenylazo)phenoxy]hexyl methacrylate} (PA6C) as the hydrophobic blocks (A) were prepared via atom transfer radical polymerization. These copolymers were prepared from bromo‐terminated macroinitiators based on PEG6000, PEG2000, and PEG600, with CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine as the catalytic system, at 85 °C in anisole. The block copolymers were characterized with 1H NMR spectroscopy and gel permeation chromatography. Differential scanning calorimetry measurements were performed to reveal the phase segregation. In contrast to those polymers with similar compositions and structures in previous reports, these amphiphilic copolymers exhibited unusual liquid‐crystalline properties over a wide temperature range, being stable even at room temperature. These copolymers showed photoresponsive isomerization under the irradiation of UV–vis light both in THF solutions and in solid films. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2225–2234, 2007
Kinetics and mechanism of the formation of poly[(1,1,3,3‐tetramethyldisiloxanyl)ethylene] and poly(methyldecylsiloxane) by hydrosilylation
Authors: AntiĆ V. V. , AntiĆ M. P. , Govedarica M. N. , DvorniĆ P. R. 
Published: April 2007

AbstractThe kinetics of the formation of poly(carbosiloxane), as well as of alkyl‐substituted poly(siloxane), by Karstedt's catalyst catalyzed hydrosilylation were investigated. Linear poly(carbosiloxane), poly[(1,1,3,3‐tetramethyldisiloxanyl)ethylene], (PTMDSE), was obtained by hydrosilylation of 1,3‐divinyltetramethyldisiloxane (DVTMDS) and 1,1,3,3‐tetramethyldisiloxane (TMDS), while alkyl‐substituted poly(siloxane), poly(methyldecylsiloxane), (PMDS), was synthesized by hydrosilylation of poly(methylhydrosiloxane) (PMHS) and 1‐decene. To investigate the kinetics of PTMDSE formation, two series of experiments were performed at reaction temperatures ranging from 25 to 56 °C and with catalyst concentrations ranging from 7.0 × 10−6 to 3.1 × 10−5 mol Pt/mol CHCH2. A series of experiments was performed at reaction temperatures ranging from 28 to 48 °C, with catalyst concentrations of 7.0 ×10−6 mol of Pt per mol of CHCH2, when kinetics of PMDS formation was investigated. All reactions were carried out in bulk, with equimolar amounts of the reacting SiH and CHCH2 groups. The course of the reactions was monitored by following the disappearance of the SiH bands using quantitative infrared spectroscopy. The results obtained showed typical first order kinetics for the PTMDSE formation, consistent with the proposed reaction mechanism. In the case of PMDS an induction period occurred at lower reaction temperatures, but disappeared at 44 °C and the rate of SiH conversion also started to follow the first‐order kinetics. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2246–2258, 2007
Molecular PCA3 diagnostics on prostatic fluid
Authors: van Gils Martijn P.M.Q. , Cornel Erik B. , Hessels Daphne , Peelen W. Pim , Witjes J. Alfred , Mulders Peter F.A. , Rittenhouse Harry G. , Schalken Jack A. 
Published: April 2007

AbstractBACKGROUNDThe PCA3 test on urine can improve specificity in prostate cancer (PCa) diagnosis and could prevent unnecessary prostate biopsies. In this study, we evaluated the PCA3 test on prostatic fluid and compared this with the PCA3 test on urine in a clinical research setting.METHODSProstatic fluid and urine samples from 67 men were collected following digital rectal examination (DRE). The sediments were analyzed using the quantitative APTIMA® PCA3 test. The results were compared with prostate biopsy results.RESULTSUsing a PCA3 score of 66 as a cut‐off value, the test on prostatic fluid had 65% sensitivity for the detection of PCa, 82% specificity and a negative predictive value of 82%. At a cut‐off value of 43, the test on urine had 61% sensitivity, 80% specificity and a negative predictive value of 80%.CONCLUSIONSThe PCA3 test can be performed on both urine and prostatic fluid in the diagnosis of PCa with comparable results. Prostate 67: 881–887, 2007. © 2007 Wiley‐Liss, Inc.
The establishment of two paclitaxel‐resistant prostate cancer cell lines and the mechanisms of paclitaxel resistance with two cell lines
Authors: Takeda Masashi , Mizokami Atsushi , Mamiya Kiminori , Li You Qiang , Zhang Jian , Keller Evan T. , Namiki Mikio 
Published: April 2007

AbstractBACKGROUNDAlthough paclitaxel is used for hormone‐resistant prostate cancer, relapse definitely occurs later. Details of the molecular mechanism responsible for paclitaxel‐ resistance remain unclear.METHODSWe established paclitaxel‐resistant cells, DU145‐TxR and PC‐3‐TxR from parent DU145 and PC‐3. To characterize these cells, we examined cross‐resistance to other anticancer drugs. Expression of several potential genes that had been related to drug‐resistance was compared with parent cells by RT‐PCR and Western blotting. Methylation analysis of multiple drug resistance (MDR1) promoter was carried out using bisulfite‐modified DNA from cell lines. Knockdown experiments using small interfering RNA (siRNA) were also performed to confirm responsibility of drug‐resistance. Finally, cDNA microarray was performed to quantify gene expression in PC‐3 and PC‐3‐TxR cells.RESULTSThe IC50 for paclitaxel in DU145‐TxR and PC‐3‐TxR was 34.0‐ and 43.4‐fold higher than that in both parent cells, respectively. Both cells showed cross‐resistance to some drugs, but not to VP‐16 and cisplatin. Methylation analysis revealed that methylated CpG sites of MDR1 promoter in DU145 and PC‐3 cells were demethylated in DU145‐TxR cells, but not in PC‐3‐TxR cells. Knockdown of P‐glycoprotein (P‐gp), which was up‐regulated in resistant cells, by MDR‐1 siRNA restored paclitaxel sensitivity in DU145‐TxR but not in PC‐3‐TxR, indicating that up‐regulation of P‐gp was not always main cause of paclitaxel‐resistance. Microarray analysis identified 201 (1.34%) up‐regulated genes and 218 (1.45%) out of screened genes in PC‐3‐TxR.CONCLUSIONSOur data will provide molecular mechanisms of paclitaxel‐resistance and be useful for screening target genes to diagnose paclitaxel sensitivity. Prostate 67: 955–967, 2007. © 2007 Wiley‐Liss, Inc.
The bisphosphonate YM529 inhibits osteoblastic bone tumor proliferation of prostate cancer
Authors: Yonou Hiroyuki , Ochiai Atsushi , Ashimine Satoshi , Maeda Hiroyuki , Horiguchi Yutaka , Yoshioka Kunihiko , Ogawa Yoshihide , Hatano Tadashi , Tachibana Masaaki 
Published: April 2007

AbstractBACKGROUNDIn men, prostate cancer frequently metastasizes to the bones, where it forms osteoblastic lesions with an osteolytic element that cause pain. However, the role of osteoclastogenesis in bone metastasis of human prostate cancer is unknown. Bisphosphonates are already known to be beneficical for treating osteolytic bone metastases, so we employed a model of osteoblastic bone tumor of human prostate cancer to investigate whether a new bisphosphonate (YM529: minodronate) could inhibit both the formation of bone tumors and the progression of established osteoblastic tumors.METHODSHuman prostate cancer cells (LNCaP) were injected into adult human bone implants in nonobese diabetic/severe combined immunodeficient mice, after which osteoblastic bone tumors developed. YM529 (1 µg/day) was administered subcutaneously every day for 2 weeks, starting either immediately or 2 weeks after implantation of the tumor cells, and the mice were sacrificed at 4 weeks after implantation. The bone tumors were examined histologically and the number of tartrate‐resistant acid phosphatase‐stained osteoclasts in each tumor focus was counted.RESULTSHistomorphometric analysis revealed that YM529 markedly inhibited both the formation of bone tumors and the progression of established tumors, as well as markedly reducing the number of osteoclasts.CONCLUSIONSYM529 reduced the tumor burden in bone by inhibiting both the formation of new lesions and the progression of existing tumors, suggesting that osteoclasts are involved in the formation of bone tumors by prostate cancer. Treatment with this bisphosphonate may potentially be beneficial for patients with bone metastases of prostate cancer. Prostate 67: 999–1009, 2007. © 2007 Wiley‐Liss, Inc.
Can an excess electron localize on a purine moiety in the adenine–thymine Watson–Crick base pair? A computational study
Authors: Mazurkiewicz Kamil , Harańczyk Maciej , Gutowski Maciej , Rak Janusz 
Published: April 2007

AbstractThe electron affinity and the propensity to electron‐induced proton transfer (PT) of hydrogen‐bonded complexes between the Watson–Crick adenine–thymine pair (AT) and simple organic acid (HX), attached to adenine in the Hoogsteen‐type configuration, were studied at the B3LYP/6‐31+G** level. Although the carboxyl group is deprotonated at physiological pH, its neutral form, COOH, resembles the peptide bond or the amide fragment in the side chain of asparagine (Asn) or glutamine (Gln). Thus, these complexes mimic the interaction between the DNA environment (e.g., proteins) and nucleobase pairs incorporated in the biopolymer. Electron attachment is thermodynamically feasible and adiabatic electron affinities range from 0.41 to 1.28 eV, while the vertical detachment energies of the resulting anions span the range of 0.39–2.88 eV. Low‐energy activation barriers separate the anionic minima: aHX(AT) from the more stable single‐PT anionic geometry, aHX(AT)‐SPT, and aHX(AT)‐SPT from the double‐PT anionic geometry, aHX(AT)‐DPT. Interaction between the adenine of the Watson–Crick AT base pair with an acidic proton donor probably counterbalances the larger EA of isolated thymine, as SOMO is almost evenly delocalized over both types of nucleic bases in the aHX(AT) anions. Moreover, as a result of PT the excess electron localizes entirely on adenine. Thus, in DNA interacting with its physiological environment, damage induced by low‐energy electrons could begin, contrary to the current view, with the formation of purine anions, which are not formed in isolated DNA because of the greater stability of anionic pyrimidines. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Visual end‐effector position error compensation for planetary robotics
Authors: Bajracharya Max , DiCicco Matthew , Backes Paul , Nickels Kevin 
Published: April 2007

AbstractThis paper describes a vision‐guided manipulation algorithm that improves arm end‐effector positioning to subpixel accuracy and meets the highly restrictive imaging and computational constraints of a planetary robotic flight system. Analytical, simulation‐based, and experimental analyses of the algorithm's effectiveness and sensitivity to camera and arm model error is presented along with results on several prototype research systems and “ground‐in‐the‐loop” technology experiments on the Mars Exploration Rover (MER) vehicles. A computationally efficient and robust subpixel end‐effector fiducial detector that is instrumental to the algorithm's ability to achieve high accuracy is also described along with its validation results on MER data. © 2007 Wiley Periodicals, Inc.
Oasis: Onboard autonomous science investigation system for opportunistic rover science
Authors: Castano Rebecca , Estlin Tara , Anderson Robert C. , Gaines Daniel M. , Castano Andres , Bornstein Benjamin , Chouinard Caroline , Judd Michele 
Published: April 2007

AbstractThe Onboard Autonomous Science Investigation System has been developed to enable a rover to identify and react to serendipitous science opportunities. Using the FIDO rover in the Mars Yard at JPL, we have successfully demonstrated a fully autonomous opportunistic science system. The closed loop system tests included the rover acquiring image data, finding rocks in the image, analyzing rock properties and identifying rocks that merit further investigation. When the system on the rover alerts the rover to take additional measurements of interesting rocks, the planning and scheduling component determines if there are enough resources to meet this additional science data request. The rover is then instructed to either turn toward the rock, or to actually move closer to the rock to take an additional, close‐up image. Prototype dust devil and cloud detection algorithms were delivered to an infusion task which refined the algorithms specifically for Mars Exploration Rovers (MER). These algorithms have been integrated into the MER flight software and were recently uploaded to the rovers on Mars. © 2007 Wiley Periodicals, Inc.
Adaptive background estimation based on robust statistics
Authors: Shimai Hiroyuki , Kurita Takio , Umeyama Shinji , Tanaka Masaru , Mishima Taketoshi 
Published: April 2007

AbstractIn this paper, the authors propose a robust background estimation algorithm, which is a technique for adaptively estimating background in response to changes in the environment based on robust statistics, and a technique for automatically adjusting the adaptation rate in response to changes in the environment. In monitoring systems and the like using stationary cameras, it is necessary to detect moving objects from the captured image series, and recognize and identify the detected subject. The most simple and representative method for moving object detection, which is used in many fields, is the background subtraction method for detecting moving objects by the difference between the background image and the current scene. This method requires a background image which does not include a moving object. However, it is difficult to acquire a background image under conditions in which moving objects are continually included in the scene. Also, when the environment changes, adaptive revision must be performed in response to the changes in the background image. Furthermore, in an environment where sections of the background change over time in different ways, it is important to determine the appropriate number of frames needed to estimate the background. In this paper, therefore, the authors propose a method for adaptive background estimation using M‐estimation, a known robust statistics technique. Also, the authors propose a technique for adjusting the number of frames necessary for background estimation by varying the adaptation rate to the environment using robust template matching. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(7): 98– 108, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10612
Calibration of fish‐eye camera for acquisition of spherical image
Authors: Nakano Masao , Li Shigang , Chiba Norishige 
Published: April 2007

AbstractThis paper proposes a method for nonmetric calibration of a fish‐eye camera that utilizes the properties of vanishing points on lines in photo scenes to join together two images facing two sides front and rear, taken with a fish‐eye camera (for this paper, a camera mounting a fish‐eye conversion lens with a field of view extending to more than one hemisphere is called a fish‐eye camera), in order to acquire a full‐view spherical image. In this method, the geometric properties of vanishing points are first used to obtain initial estimates of the optical center and focal distance on the image, which are the internal parameters for the fish‐eye camera. Next, the photo images of the two sides are each mapped onto a spherical surface, and binding conditions, in which true parameter values are used to join the two resulting hemispherical images into a single spherical image, are used to perform fine adjustment of the parameters, based on image correlation of overlapping sections of the front and rear photo images. Experiments using actual still scene images showed the validity of the method, and the proposed method was used to build a system capable of shooting full‐view images in real time. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(6): 10–20, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20631 Copyright © 2004 Wiley Periodicals, Inc.
A fast algorithm for reconstruction‐based superresolution and evaluation of its accuracy
Authors: Tanaka Masayuki , Okutomi Masatoshi 
Published: April 2007

AbstractA superresolution process produces a high‐resolution image from a set of low‐resolution images. Reconstruction‐based algorithms to produce the high‐resolution image which minimizes the difference between observed images and images estimated from the high‐resolution image with a camera model have been developed. The reconstruction‐based algorithm requires iterative calculation and has a large calculation cost because reconstruction‐based superresolution is a large‐scale problem. In this paper, a fast algorithm for reconstruction‐based superresolution is proposed. The proposed algorithm reduces the number of observed pixel value estimations from the high‐resolution image, using an average of pixel values in a divided region. The effect of our proposed algorithm is demonstrated with synthetic images and real images. The results show that the proposed algorithm is about 1.4 to 8.5 times faster than conventional algorithms. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(7): 44–52, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20662
Motion‐compensated video coding using sliced blocks
Authors: Kondo Satoshi , Sasai Hisao 
Published: April 2007

AbstractIn international standards for video coding such as MPEG‐4 and H.264, motion compensation is performed by partitioning macroblocks (square pixel sets) into multiple areas. In this paper, we propose motion compensation using sliced blocks as a new method for macroblock‐based motion compensation. The partition shape is not restricted to squares or other patterns; instead, macroblocks are sliced by arbitrary line segments. This produces better agreement in shape between partitions and moving objects, as well as better motion compensation performance. In addition, when partition data are described in bitstream, adaptive prediction of segments based on partition shape of neighbor macroblocks is applied, aiming at reduction of the overhead caused by partition data. In the proposed method, coding is performed at the macroblock level, and therefore, coding mode selection and other related algorithms of conventional rate distortion optimization can be used unaltered. The proposed method was applied to forward‐prediction picture coding (basic algorithm of H.264), and an improvement of coding efficiency by about 5% was confirmed. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(7): 12– 22, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20714