bluuebunny/crossref_metadata_2025 huggingface dataset:
Developmental variability during early embryonic development of zebra fish, Danio rerio
Authors: Schmidt Kai , Starck J. Matthias
Published: August 2004

Early vertebrate embryos pass through a period of remarkable morphological similarity. Possible causes for such similarity of early embryos include modularity, developmental constraints, stabilizing selection, canalization, and exhausted genetic variability. Supposedly, each process creates different patterns of variation and covariation of embryonic traits. We study the patterns of variation of the embryonic phenotype to test ideas about possible evolutionary mechanisms shaping the early embryonic development. We use the zebra fish, Danio rerio, as a model organism and apply repeated measures of individual embryos to study temporal changes of phenotypic variability during development. In particular, we are looking at the embryonic development from 12 hours post fertilization until 27 hours post fertilization. During this time period, the development of individual embryos is documented at hourly intervals. We measured maximum diameter of the eye, length of embryo, number of somites, inclination of somites, and the yolk size (as a maternal effect). The coefficient of variation (CV) was used as a measure of variability that was independent of size. We used a principal component analysis for analysis of morphological integration. The experimental setup kept environment × genotype interactions constant. Nongenetic parental contributions had no significant effects on interindividual variability. Thus all observed phenotypic variation was based on additive genetic variance and error variance. The average CV declined from 14% to 7.7%. The decline of the CV was in particular expressed during 15–19 h post fertilization and occurred in association with multiple correlations among embryonic traits and a relatively high degree of morphological integration. We suggest that internal constraints determine the patterns of variability during early embryonic development of zebra fish. J. Exp. Zool. (Mol. Dev. Evol.) 302B:000000, 2004. © 2004 Wiley‐Liss, Inc.
Developmental fate of the mandibular mesoderm in the lamprey, Lethenteron japonicum: Comparative morphology and development of the gnathostome jaw with special reference to the nature of the trabecula cranii
Authors: Kuratani Shigeru , Murakami Yasunori , Nobusada Yoshiaki , Kusakabe Rie , Hirano Shigeki
Published: August 2004

The vertebrate jaw is a mandibular‐arch derivative, and is regarded as the synapomorphy that defines the gnathostomes. Previous studies (Kuratani et al., Phil. Trans. Roy. Soc. 356:15, 2001; Shigetani et al., Science 296:1319, 2002) have suggested that the oral apparatus of the lamprey is derived from both the mandibular and premandibular regions, and that the jaw has arisen as a secondary narrowing of the oral patterning mechanism into the mandibular‐arch domain. The heterotopy theory of jaw evolution states that the lamprey upper lip is a premandibular element, leaving further questions unanswered as to the homology of the trabecula in the lamprey and gnathostomes, and to the morphological nature of the muscles in the upper lip. Using focal injection of vital dyes into the cheek process core of lamprey embryos, we found that the upper lip muscle and trabecula are both derived from mandibular mesoderm. Secondary movement of the muscle primordium is also evident when the expression of the early muscle marker gene, LjMA2, is visualized. A nerve‐fiber labeling study revealed that the upper lip muscle‐innervating neurons are located in the rostral part of the brain stem, where the trigeminal motor nuclei are not found in gnathostomes. We conclude that the lamprey upper lip is composed of premandibular ectomesenchyme and a lamprey‐specific muscle component derived from the mandibular mesoderm innervated by lamprey‐specific motoneurons. Furthermore, the lamprey trabecula is most likely equivalent to a mesodermally derived neurocranial element, similar to the parachordal element in gnathostomes, rather than to the neural‐crest‐derived prechordal element. J. Exp. Zool. (Mol. Dev. Evol.) 302B:000–000, 2004. © 2004 Wiley‐Liss, Inc.
Internal energy and fragmentation of ions produced in electrospray sources
Authors: Gabelica Valérie , Pauw Edwin De
Published: August 2004

This review addresses the determination of the internal energy of ions produced by electrospray ionization (ESI) sources, and the influence of the internal energy on analyte fragmentation. A control of the analyte internal energy is crucial for several applications of electrospray mass spectrometry, like structural studies, construction of reproducible and exportable spectral libraries, analysis of non‐covalent complexes. Sections II and III summarize the Electrospray mechanisms and source design considerations which are relevant to the problem of internal energy, and Section IV gives an overview of the inter‐relationships between ion internal energy, reaction time scale, and analyte fragmentation. In these three sections we tried to make the most important theoretical elements understandable by all ESI users, and their understanding requires a minimal background in physical chemistry. We then present the different approaches used to experimentally determine the ion internal energy, as well as various attempts in modeling the internal energy uptake in electrospray sources. Finally, a tentative comparison between electrospray and other ionization sources is made. As the reader will see, although many reports appeared on the subject, the knowledge in the field of internal energy of ions produced by soft ionization sources is still scarce, because of the complexity of the system, and this is what makes this area of research so interesting. The last section presents some perspectives for future research. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 24:566–587, 2005
The use of statistical MUNE in a multicenter clinical trial
Authors: Shefner J. M. , Cudkowicz M. E. , Zhang H. , Schoenfeld D. , Jillapalli D. ,   the Northeast ALS Consortium
Published: August 2004

Techniques to estimate motor unit number (MUNE) measure the number of functioning motor units in a muscle. In diseases characterized by progressive motor unit loss, such as amyotrophic lateral sclerosis (ALS), MUNE may be useful to monitor disease progression or beneficial response to treatment. As part of a multicenter, placebo‐controlled, randomized, double‐blind clinical trial testing the efficacy of creatine in patients with ALS, statistical MUNE was measured in 104 patients tested monthly for 6 months. The objective was to determine whether MUNE was a reliable and sensitive outcome measure in the context of a multicenter trial. Formal training and reliability testing was required for all MUNE evaluators. Testing of normal controls showed a high degree of test–retest reliability. All patient data were combined as the experimental treatment showed no efficacy. There was a 23% decline in MUNE over 6 months. The technique as employed in this trial overemphasized the presence of small motor units; this problem was partially addressed by poststudy data monitoring and censuring. Thus, MUNE can be used reliably as an outcome measure in multicenter clinical trials; specific remedies are suggested for the difficulties encountered in this study. Muscle Nerve 30: 463–469, 2004
Apparent conduction block in patients with ulnar neuropathy at the elbow and proximal Martin–Gruber anastomosis
Authors: Whitaker Charles H. , Felice Kevin J.
Published: August 2004

A Martin–Gruber anastomosis (MGA) commonly results in an abnormal decline in amplitude across the forearm segment when ulnar motor nerve conduction studies are performed. A recent report described a proximal MGA resembling partial conduction block in a patient with ulnar neuropathy at the elbow (UNE). As a result, we screened patients with similar findings. We detected a proximal MGA in three patients over a period of 2 years, which suggests that this may be an under‐recognized anomaly. We conclude that a proximal MGA must be excluded in all cases of UNE showing apparent partial conduction block across the elbow segment. Muscle Nerve, 2004
Nitric oxide synthase and soluble guanylyl cyclase underlying the modulation of electrical oscillations in a central olfactory organ
Authors: Fujie Sayoko , Yamamoto Takehiro , Murakami Jun , Hatakeyama Dai , Shiga Hatsuki , Suzuki Norio , Ito Etsuro
Published: August 2004

We have isolated and characterized the cDNAs for nitric oxide synthase (NOS) and soluble guanylyl cyclase (sGC) from the terrestrial slug Limax marginatus, and examined the presence and distribution of their mRNAs in the central nervous system using histological techniques and a reverse transcription‐polymerase chain reaction method. Our results showed that both bursting and nonbursting neurons in the procerebral lobes contain the mRNAs for both NOS and sGC. We further found that the oscillation frequency of electrical activity in the procerebral lobes increases with increasing intracellular concentrations of cyclic GMP (cGMP). Taken together with previous data on the NO‐induced cGMP‐like immunoreactivity and on the anatomical distribution of neurites and the localization of synapses of bursting and nonbursting neurons, our present results suggest that NO‐induced changes in cGMP concentration modulate the oscillation frequency in the procerebral lobes by acting on the olfactory input pathways, but possibly not on the output pathways, in slugs. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2005
Charged up: Creating energy in organizations
Authors: Cross Rob , Parker Andrew
Published: August 2004

The ability of an individual to energize others is a determinant of individual and group success. People who are “energizers” are more effective at motivating others, eliciting productive solutions, getting work done, and advancing their careers. Drawing on their research into social networks, the authors examine five dimensions of energizing relationships and offer some simple questions for determining whether you are an energizer or a de‐energizer. © 2004 by Harvard Business School Publishing Corporation
Change management underpins a successful ERP implementation at Marathon Oil
Authors: Stapleton Gregg , Rezak Catherine J.
Published: August 2004

Enterprise Resource Planning (ERP) systems promise heaven, but the implementation is often just the opposite—cost overruns, exponentially expanding timelines, functionality shortfalls, even business failures. Yet ERP is as essential to the “new economy” as automation was to the old. Marathon Oil Corporation made this business‐critical changeover in record time and within the constraints of an aggressive budget. Flawless execution on the technical side was essential, but managing change—the people side of the implementation—was a key ingredient for success. © 2004 Wiley Periodicals, Inc.
How outback steakhouse created a great place to work, have fun, and make money
Authors: DeCotiis Tom , Sullivan Chris , Hyatt David , Avery Paul
Published: August 2004

When the rapid growth of Outback Steakhouse restaurants began to threaten the founders' vision of a values‐driven organization, the company's leaders embarked on a process to infuse every one of its restaurants with a culture that has become a hallmark in the industry. At the heart of this culture is a strong commitment to make Outback a great place to work, have fun, and make money—a reflection of the founders' belief that employees are key to meeting the company's commitments to all its stakeholders. © 2004 Wiley Periodicals, Inc.
From bureaucracy to meritocracy and customer focus: A Georgia state agency reinvents itself
Authors: Vinyard John
Published: August 2004

The five‐year history of Georgia's Office of State Administrative Hearings (OSAH) had been marked with rampant internal strife, inefficient work practices, customer dissatisfaction, and frequent changes in top leadership. With the Malcolm Baldrige criteria for performance excellence as a model, the new chief judge worked with a transition team to sow a new culture of mutual respect, teamwork, high performance, and customer service. Concurrently, the agency implemented a range of structural, systems, and process changes to support the new culture and a strong customer focus. These changes produced rapid and sustained improvements in performance and have made OSAH a public‐sector success story. © 2004 Wiley Periodicals, Inc.
A new study identifies the “makes and breaks” of diversity initiatives
Authors: Matton Janine N. , Hernandez Christine M.
Published: August 2004

A recent study of ten companies examined the success factors and challenges in diversity and compliance initiatives that attempt to address the entrenched effects of second‐generation bias and discrimination in the workplace. Success of these initiatives hinged on having targets/goals and other measures of effectiveness, committed leadership, a strong diversity/compliance professional, employee involvement, ties to performance evaluation, and access to solid data for identifying, quantifying, and communicating problems and progress. But significant challenges remain, including replicating for minorities the progress being made for women. © 2004 by Janine N. Matton and Christine M. Hernandez
Six principles for designing the accountable organization
Authors: Dalziel Murray , DeVoge Sylvia , LeMaire Katie
Published: August 2004

Organizational redesign is often a knee‐jerk reaction to performance problems, often done incompletely or with little attention to the potential impact on other jobs and parts of the organization. The resulting accountability gaps and redundancies can further hamstring performance. Six straightforward principles, garnered from the practices of America's best performing companies, focus on getting design right for the most fundamental building blocks of an organization—jobs, team, and processes. © 2004 Hay Group, Inc.
The role of c‐Jun and c‐Fos expression in androgen‐independent prostate cancer
Authors: Edwards Joanne , Krishna N Sarath , Mukherjee Rono , Bartlett John MS
Published: August 2004

Molecular mechanisms underlying the development of androgen‐insensitive prostate cancer (AIPC) are poorly understood. However, there is growing evidence that different molecular profiles may result in the development of AIPC. Cell line studies demonstrate that c‐Jun and c‐Fos, via formation of the transcription factor activated protein 1 (AP‐1), activate androgen‐regulated genes independent of androgens and that c‐Jun alone acts as an androgen receptor co‐factor. The aim of this study was to investigate whether increased levels of c‐Jun and phosphorylated c‐Jun are associated with the development of AIPC using clinical material. Material from a cohort of 51 patients with paired tumours, obtained before and after the development of AIPC, and with full clinical biochemical follow‐up, was retrieved from the archives. Tumour c‐Jun, activated c‐Jun, c‐Fos, and pan protein kinase C (PKC) protein expression were analysed by immunohistochemistry and protein expression was scored by two independent observers using a weighted histoscore. No evidence was found to suggest that c‐Jun acting as an androgen receptor co‐factor influences the development of AIPC. However, it was observed that patients with high expression levels of phosphorylated c‐Jun had a significantly shorter survival from relapse compared with patients with low phosphorylated c‐Jun protein expression (p = 0.023), suggesting that increased AP‐1 levels may promote AIPC tumour growth. Whilst PKC did not appear to activate c‐Jun in vivo, increased PKC expression in AIPC tumours was also associated with decreased patient survival from time of relapse (p = 0.014). In conclusion, the data support the hypothesis that activation of c‐Jun plays a role in the development of AIPC via AP‐1 formation in some patients. However, PKC appears to promote the development of AIPC independently of c‐Jun activation via an as yet unexplained mechanism. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
The androgen receptor co‐activator CBP is up‐regulated following androgen withdrawal and is highly expressed in advanced prostate cancer
Authors: Comuzzi Barbara , Nemes Constanze , Schmidt Stefan , Jasarevic Zerina , Lodde Michele , Pycha Armin , Bartsch Georg , Offner Felix , Culig Zoran , Hobisch Alfred
Published: August 2004

The androgen receptor co‐activator CREB (cAMP‐response element binding protein)‐binding protein (CBP) enhances androgen receptor activity after stimulation by androgenic hormones and androgen receptor antagonists. The aim of the present study was to investigate the regulation of CBP expression by steroid and peptide hormones in prostate cancer. For this purpose, LNCaP cells were treated with the synthetic androgen methyltrienolone (R1881), epidermal growth factor, insulin‐like growth factor‐I or interleukin‐6 (IL‐6). CBP protein and mRNA expression were studied by western blotting and real‐time PCR, respectively. CBP expression was also investigated in tissue specimens obtained from 26 patients with therapy‐resistant carcinoma of the prostate. In LNCaP cells, CBP protein was down‐regulated by R1881 or IL‐6. The non‐steroidal anti‐androgen bicalutamide antagonized the effects of R1881 and the Janus kinase inhibitor AG 490 reversed the effects of IL‐6. In contrast, neither R1881 nor IL‐6 caused any effect on CBP expression in the PC‐3 cell line. In LNCaP cells, the inhibition of CBP expression by R1881 or IL‐6 was also observed at the mRNA level. CBP protein was detected in all 26 specimens by immunohistochemistry. The results suggest that up‐regulation of CBP during androgen ablation may be relevant to the failure of endocrine therapy in patients with prostate carcinoma. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Involvement of E‐cadherin and β‐catenin in germ cell tumours and in normal male fetal germ cell development
Authors: Honecker Friedemann , Kersemaekers Anne‐Marie F , Molier Michel , van Weeren Pascale C , Stoop Hans , de Krijger Ronald R , Wolffenbuttel Katja P , Oosterhuis Wolter , Bokemeyer Carsten , Looijenga Leendert HJ
Published: August 2004

Intercellular contacts, mediated by E‐cadherin, are essential for germ cell migration and maturation. Furthermore, it has been suggested that decrease or loss of E‐cadherin correlates with tumour progression and invasive behaviour. β‐catenin is involved in a number of different processes, including cell–cell interaction when bound to cadherins, and determination of cell fate in pluripotent cells when activated via the Wnt signal‐transduction pathway. To shed more light on the role of these factors in normal fetal germ cell development and the pathogenesis of germ cell tumours (GCTs), the present study investigated the presence and localization of E‐cadherin and β‐catenin by immunohistochemistry. E‐cadherin was only weakly expressed in or absent from fetal germ cells of the second and third trimesters, and was not expressed in carcinoma in situ/intratubular germ cell neoplasia unclassified (CIS/ITGCNU) and gonadoblastoma, the precursor of an invasive GCT in dysgenetic gonads. In GCTs, it was generally not expressed in seminoma and dysgerminoma, but was found in the vast majority of non‐seminoma cells. β‐catenin was found in the cytoplasm of fetal germ cells at all gestational ages and in spermatogenesis in post‐pubertal testes. It was also present in CIS/ITGCNU and gonadoblastoma. Whereas seminomas and dysgerminoma were negative, non‐seminoma cells were frequently found to express β‐catenin. Expression of both factors therefore reflects the degree of differentiation of these tumours. No differences for either E‐cadherin or β‐catenin were observed between samples of tumours resistant or sensitive to chemotherapy, and E‐cadherin expression did not correlate with vascular invasion. E‐cadherin and β‐catenin therefore play a role in both normal and malignant germ cell development and differentiation that warrants further investigation, but they seem to be of limited value as predictive or prognostic factors in GCTs. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Morphological changes in tumour type after radiotherapy are accompanied by changes in gene expression profile but not in clinical behaviour
Authors: Nagtegaal Iris , Gaspar Claudia , Marijnen Corrie , van de Velde Cornelis , Fodde Riccardo , van Krieken Han
Published: August 2004

The morphological features of neoplastic cells, combined with a stromal reaction, determine the presence of cancer at the microscopic level. Malignant tumours arise through a series of genetic alterations, but these do not entirely explain invasive and metastatic behaviour and correlate only weakly with morphological changes. In order to understand the relationship between the morphology of cancer tissue, gene expression, and clinical behaviour, a study of radiation‐induced mucinous rectal carcinoma was performed. Short‐term radiotherapy of rectal carcinoma results in an increased incidence of mucinous carcinoma. A cohort of rectal carcinomas (n = 1304), from patients who participated in a randomized radiotherapy trial, was evaluated for the presence and amount of a mucinous component. The results were compared with data from the pre‐irradiation biopsies and revealed the presence of two distinct classes of mucinous carcinoma in the radiotherapy group, namely pre‐existing (un‐induced; n = 24) and induced mucinous carcinoma (n = 29). Clinical data, pathological parameters, and immunohistochemical data from these patients and their tumours showed that induced mucinous carcinomas were more comparable to typical adenocarcinomas than to pre‐existing mucinous carcinomas. The prognosis of patients with induced mucinous carcinoma was significantly better than that of patients with pre‐existing mucinous carcinomas (91.2% versus 39.3% recurrence‐free interval at 2 years, p = 0.02). Gene expression profiles of the different groups of mucinous carcinomas and adenocarcinomas were analysed using Affymetrix Human Cancer Chips. Surprisingly, despite the difference in prognosis, the expression profile of radiation‐induced mucinous carcinomas was very closely related to that of their un‐induced counterparts. It is shown in the present study that radiation therapy of rectal cancer leads within a few days to substantial changes in both morphology and expression profile. However, the morphology of the pre‐therapy biopsy predicts patient survival far better than post‐therapy expression profiles. It is concluded that tumour morphology equates to expression profile, but that external factors might influence both, leading to sub‐optimal prognostication. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Synthesis and property of helical poly(phenylacetylene)s bearing chiral ruthenium complexes and real space imaging of meso‐ and nanoscopic structures by atomic force microscopy
Authors: Sakurai Shin‐ichiro , Ohira Akihiro , Suzuki Yoshinori , Fujito Riri , Nishimura Tatsuya , Kunitake Masashi , Yashima Eiji
Published: August 2004

Novel sets of helical poly(phenylacetylene)s bearing a chiral ruthenium (Ru) complex with opposite chirality (Δ and Λ forms) as a bulky pendant (poly‐1 and poly‐2) were synthesized through the polymerization of the corresponding optically pure phenylacetylenes with a rhodium catalyst, and their structures in solution and morphology on solid substrates were investigated with NMR, ultraviolet–visible, and circular dichroism (CD) spectroscopies and with atomic force microscopy (AFM), respectively. The obtained cis–transoidal polymers (poly‐1 and poly‐2) showed characteristic Cotton effects in the region of metal‐to‐ligand charge transfer of the chiral Ru pendants. Poly‐1 and poly‐2 were thought to have a predominantly one‐handed helical conformation induced by the chiral pendants. However, the apparent Cotton effects derived from the helically twisted π‐conjugated polymer backbone could not be observed, probably because of the strong chiral chromophoric pendants. However, in the AFM images, the helical polymers adsorbed on mica could be easily discerned as isolated strands, and the visualization and discrimination of the right‐ and left‐handed helical structures of the chiral polymers were achieved by high‐resolution AFM imaging. On the basis of the AFM observations together with the CD measurements and computational calculation results, possible structures of poly‐1 and poly‐2 were examined. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4621–4640, 2004
Asymmetric anionic polymerization of optically active N‐1‐cyclohexylethylmaleimide
Authors: Onimura Kenjiro , Zhang Yuan , Yagyu Michihiro , Oishi Tsutomu
Published: August 2004

Chiral (S)‐(−)‐N‐1‐cyclohexylethylmaleimide [(S)‐CEMI] and (R)‐(+)‐N‐1‐cyclohexylethylmaleimide [(R)‐CEMI] were synthesized successfully and then polymerized with chiral complexes of (−)‐sparteine or (S,S)‐(1‐ethylpropylidene)bis(4‐benzyl‐2‐oxazoline) [(S,S)‐Bnbox] and organometal as initiators in toluene or tetrahydrofuran to obtain optically active polymers. The effects of the polymerization conditions on the optical activity and structure of poly(N‐1‐cyclohexylethylmaleimide)s were investigated with gel permeation chromatography, circular dichroism, specific rotation, and 13C NMR measurements. Poly[(R)‐CEMI] obtained with dimethylzinc (Me2Zn)/(S,S)‐Bnbox had the highest specific rotation ([α]435 = +323.7°). Complexes of Bnbox and diethylzinc or Me2Zn were used very effectively as chiral initiators for the asymmetric anionic polymerization of (S)‐CEMI and (R)‐CEMI. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4682–4692, 2004
Stereospecific polymerization of 9‐fluorenyl methacrylate: Tacticity effects on the thermal and photophysical properties of the polymers
Authors: Ishizawa Hideaki , Nakano Tamaki , Yade Tohru , Tsuji Masashi , Nakagawa Osamu , Yamaguchi Takashi
Published: August 2004

Poly(9‐fluoreneyl methacrylate) was obtained through anionic polymerization with t‐BuLi and t‐BuMgBr and through radical polymerization with α,α′‐azobisisobutyronitrile. Anionic polymerization with t‐BuLi in tetrahydrofuran and radical polymerization afforded syndiotactic polymers (rr ∼ 90%), whereas anionic polymerization with Li and Mg initiators in toluene and CH2Cl2 led to isotactic polymers. The thermal and photophysical properties of the polymers were examined. A syndiotactic polymer tended to show higher glass transition and decomposition temperatures than an isotactic polymer. However, polymers with different tacticities were not likely to assume specific, distinctive conformations such as a helix or a π‐stacked conformation in solution. An isotactic polymer showed stronger interactions in a CH2Cl2 solution with 2,4,7‐trinitro‐9‐fluorenylidenemalononitrile, an electron‐acceptor molecule, than a syndiotactic polymer. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4656–4665, 2004
Phenylcarbamate derivatives of cellulose and amylose immobilized onto silica gel as chiral stationary phases for high‐performance liquid chromatography
Authors: Kubota Takateru , Yamamoto Chiyo , Okamoto Yoshio
Published: August 2004

Three polysaccharide phenylcarbamate derivatives [cellulose 2,3‐bis(3,5‐dimethylphenylcarbamate)‐6‐(3,5‐dimethylphenylcarbamate)/(2‐methacryloyloxyethylcarbamate), cellulose 2,3‐bis(3,5‐dichlorophenylcarbamate)‐6‐(3,5‐dichlorophenylcarbamate)/(2‐methacryloyloxyethylcarbamate), and amylose 2,3‐bis(3, 5‐dimethylphenylcarbamate)‐6‐(3,5‐dimethylphenylcarbamate)/(2‐methacryloyloxyethylcarbamate)] with vinyl groups were prepared and coated onto silica gel to immobilize them via radical copolymerization with 2,3‐dimethylbutadiene. The copolymerization efficiently proceeded, and the coated polysaccharide derivatives were mostly immobilized on the surface of the silica gel. The immobilized polysaccharide derivatives showed high chiral recognition abilities similar to those of the corresponding coated polysaccharide derivatives. They could be used with an eluent containing chloroform, which dissolved the polysaccharide derivatives. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4704–4710, 2004
Asymmetric radical cyclization of (2S,3S)‐2,3‐butanediyl, (2S,4S)‐2,4‐pentanediyl, and (2S,5S)‐2,5‐hexanediyl bis(4‐vinylbenzoate)s as a model reaction for asymmetric cyclocopolymerization
Authors: Obata Makoto , Yano Shigenobu , Kamino Kazunobu , Yokota Kazuaki , Kakuchi Toyoji
Published: August 2004

The asymmetric cyclocopolymerization of bis(4‐vinylbezoate) of a chiral diol with styrene is a promising method for the preparation of optically active polystyrene derivatives because of main‐chain chirality. However, the mechanism for chirality induction from the chiral diol to the main chain is still unknown. To clarify the chirality induction mechanism, we carried out the radical cyclizations of (2S,3S)‐2,3‐butanediyl bis(4‐vinylbenzoate), (2S,4S)‐2,4‐pentanediyl bis(4‐vinylbenzoate), and (2S,5S)‐2,5‐hexanediyl bis(4‐vinylbenzoate) with tri‐n‐butyltin hydride or allyltri‐n‐butyltin as a chain‐transfer reagent as model reactions for asymmetric cyclocopolymerization. The absolute configuration was determined with single‐crystal X‐ray crystallography and a circular dichroism exciton chirality method. The distribution of the stereoisomer showed (R)‐configuration selectivity (21–34% diastereomeric excess) in the intramolecular cyclization and an extremely low extent (<1%) of the (S,S)‐cyclized product among the four stereoisomers. Therefore, chirality induction is caused by the selective inhibition of the (S,S)‐racemo configuration. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4671–4681, 2004
Synthesis of chiral polyacetylenes carrying amino acids and azobenzenes and transformation of the higher order structure by photoirradiation
Authors: Sanda Fumio , Teraura Takayuki , Masuda Toshio
Published: August 2004

This study examined the synthesis of copolymers of an alanine‐derived chiral N‐propargylamide [N‐(tert‐butoxycarbonyl)‐L‐alanine N′‐propargylamide] with an azobenzene‐containing N‐propargylamide [N‐4‐(phenylazo)benzoyl‐L‐alanine N′‐propargylamide] and the transformation of the higher order structure of the copolymers by photoirradiation. The trans‐azobenzene moiety of the copolymers isomerized into the cis one, which was accompanied by the transformation of the helical structure into a random state by UV irradiation. Visible‐light irradiation induced the reisomerization of cis‐azobenzene into the trans one, but it did not induce the recovery of the higher order structure. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4641–4647, 2004
Stereological simulations of asymmetric polymerization in channels of bile acid inclusion compounds: A detailed analysis of the monomer arrangements in the channels
Authors: Inoue Katsunari , Kato Kazuaki , Tohnai Norimitsu , Miyata Mikiji
Published: August 2004

We studied simulations by computer graphics to estimate the steric mechanism of the asymmetric polymerization of prochiral diene monomers in channels of inclusion compounds of steroidal bile acids, such as deoxycholic acid (DCA) and cholic acid. We applied a hierarchization method to interpret the crystal structures of bile acids, clarifying that the chiral host molecules associated to form characteristic 21‐helical assemblies with uneven surfaces. A detailed analysis of the uneven channels in a close‐packing state indicated that there were many possible arrangements of the monomers in the channels. The plausible arrangements in the channel could explain a previous study, which showed that the polymerization in the DCA channel yielded chiral polymers with a predominant configuration from prochiral diene monomers, such as 2‐methyl‐trans‐1,3‐pentadiene. On the basis of such simulation studies of the arrangements of guest monomers in the channel, we examined a plausible steric mechanism for asymmetric inclusion polymerization. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4648–4655, 2004
Syntheses of helical polymers through the combination of axially dissymmetric segments
Authors: Temma Tomohisa , Kobayashi Motoyasu , Agata Yuya , Yamane Tomoya , Miura Jun , Takeishi Makoto
Published: August 2004

Wholly aromatic polymers with various helical structures were prepared through the combination of two axially dissymmetric bifunctional compounds. The palladium‐catalyzed condensation of (R)‐2,2‐diethoxy‐6,6′‐dibromo‐1,1′‐binaphthyl with (R)‐1,1′‐binaphthyl‐2,2′‐diamine and the reaction of (S)‐2,2‐diethoxy‐6,6′‐dibromo‐1,1′‐binaphthyl with (S)‐1,1′‐binaphthyl‐2,2′‐diamine produced helical polyamines, and the chiral conformation was confirmed by their circular dichroism spectra and large specific rotations. The combination of (R)‐2,2‐diethoxy‐6,6′‐dibromo‐1,1′‐binaphthyl and (S)‐1,1′‐binaphthyl‐2,2′‐diamine afforded polyamines with a zigzag conformation. The condensation of (R)‐2,2′‐dimethylbiphenyl‐6,6′‐dicarbonyl chloride with (R)‐2,2′‐diamino‐6,6′‐dimethylbiphenyl and the reaction of (S)‐2,2′‐dimethylbiphenyl‐6,6′‐dicarbonyl chloride with (S)‐2,2′‐diamino‐6,6′‐dimethylbiphenyl predominantly yielded cyclic dimers and tetramers because of the steric proximity of the reactive groups of the propagating species. The experimental results indicated that the structures of the obtained polymers depended on the combination of the chirality of the bifunctional atropisomeric compounds and the position of the functional groups on the aromatic rings. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4607–4620, 2004
Convenient synthesis of fully and partially deuterated stereoregular poly(phenylacetylene)s bearing a carboxy pendant and helicity induction on the polymers with chiral amines and its memory
Authors: Morino Kazuhide , Asari Takeshi , Maeda Katsuhiro , Yashima Eiji
Published: August 2004

Poly[(4‐carboxyphenyl)acetylene] and its derivatives deuterated in the main chain and/or on the phenyl group (poly‐1's) were conveniently synthesized by the polymerization of 4‐ethynylbenzoic acid or its derivative deuterated on the phenyl group in the presence of bases with a water‐soluble rhodium complex in water or deuterium oxide. The obtained polymers possesses highly cis–transoidal stereoregular structures according to NMR and Raman spectroscopy. Possible deuterium isotope effects of these partially and fully deuterated poly‐1's during the helicity induction with chiral amines and its memory assisted by achiral amines were investigated. The thermal cis–trans isomerization of the methyl esters of poly‐1's was also studied with 1H NMR spectroscopy. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4711–4722, 2004
Characterization of the benzene‐insoluble fraction of the hydrolyzate of phenyltrimethoxysilanes in the presence of benzyltrimethylammonium hydroxide
Authors: Pakjamsai Chitsakon , Kobayashi Noritomo , Koyano Mikio , Sasaki Shintaro , Kawakami Yusuke
Published: August 2004

The insoluble fraction obtained from the hydrolysis and condensation of (4‐dimethylamino‐, 2‐methyl‐, and nonsubstituted)phenyltrimethoxysilanes in the presence of benzyltrimethylammonium hydroxide in benzene was characterized. IR, 1H NMR, and 29Si NMR suggested that the insoluble fraction was composed of RSi(O)3, that is, a T3 structure. X‐ray diffraction indicated the presence of a long‐range ordered structure composed of a mixture of crystals. Raman spectroscopy strongly suggested a cage structure by the presence of a ring‐opening vibration assignable to a cubic structure at 475–482 cm−1. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4587–4597, 2004
Synthesis of a polyester macromonomer via the cobalt‐catalyzed alternating copolymerization of propylene oxide and carbon monoxide
Authors: Nakano Koji , Fumitaka Kondo , Nozaki Kyoko
Published: August 2004

The alternating copolymerization of propylene oxide and carbon monoxide was investigated with cobalt complexes. The NaCo(CO)4/amine catalyst system selectively yielded oligo(3‐hydroxybutyrate)s bearing a polymerizable crotonate end group, whereas the use of Co2(CO)8 as a cobalt source resulted in a smaller concentration of the crotonate end group and a high degree of polymerization. The high selectivity for the oligoesters with the crotonate end group with the NaCo(CO)4/amine system was attributed to its more basic reaction condition. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4666–4670, 2004
Chemoenzymatic synthesis of glycoconjugate polymers starting from nonreducing disaccharides
Authors: Miura Yoshiko , Wada Natsuko , Nishida Yoshihiro , Mori Hiroshi , Kobayashi Kazukiyo
Published: August 2004

Here we report the chemoenzymatic synthesis and recognition function of glycoconjugate polymers carrying nonreducing disaccharides [α‐D‐glucopyranosyl‐(1‐1)‐α‐D‐glucopyranoside (trehalose) and α‐D‐galactopyranosyl‐(1‐1)‐α‐D‐glucopyranoside (Gal‐type trehalose)]. The lipase‐catalyzed esterification of the disaccharides with divinyl sebacate is completely selective at the primary Glc 6‐OH position of trehalose and at the Gal 6‐OH position of Gal‐type trehalose. The resultant vinyl esters can be polymerized to yield glycoconjugate polymers with poly(vinyl alcohol) backbones. The interactions of the glycoconjugate polymers with lectins (concanavalin A and Bandeiraera simplicifolia) are amplified because of the glycocluster effect. The polymer carrying pendant α‐D‐galactopyranosyl‐(1‐1)‐α‐D‐glucopyranoside shows inhibition activity against Shiga toxin‐1 based on a stereochemical structure similar to that of globosyl Gb2 disaccharide. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4598–4606, 2004
Design and synthesis of chiral poly(binaphthyl salen zinc complex) and application of the asymmetric field based on its helical conformation to a catalytic asymmetric reaction
Authors: Maeda Takeshi , Takeuchi Takeshi , Furusho Yoshio , Takata Toshikazu
Published: August 2004

According to a rational design of helices (i.e., fusing C2 chiral binaphthyl units and metallosalen complexes inevitably results in the formation of helical polymers), chiral poly(binaphthyl salen zinc complex)es (3‐Zn) were synthesized from an (R)‐3,3′‐diformylbinaphthol derivative, α,ω‐diamines, and zinc acetate or diethylzinc. Their helical structures were well supported by their infrared, ultraviolet, and circular dichroism spectra, in addition to MM calculations and a CPK model study. The catalysis of 3‐Zn during the asymmetric addition of diethylzinc to aldehydes was investigated. In the presence of 5 unit mol % 3‐Zn, diethylzinc reacted with benzaldehyde to yield 1‐phenyl‐1‐propanol in high yields (∼100%) and with high enantioselectivity (∼95%). The asymmetric yield of 1‐phenyl‐1‐propanol increased significantly as the temperature was lowered, whereas both the asymmetric yield and the absolute configuration were drastically changed as the structure of the diamine unit of 3‐Zn was varied. Several aromatic aldehydes were converted into their corresponding alcohols with high enantioselectivity. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4693–4703, 2004
Crystallization of propylene–ethylene random copolymers
Authors: Weng J. , Olley R. H. , Bassett D. C. , Jääskeläinen P.
Published: August 2004

Of the three melting peaks typical of a propylene–ethylene random copolymer (with 5.1 wt % ethylene) crystallized between 110 and 140 °C, the two higher peaks result from primary and secondary isothermal crystallization, whereas the material crystallized on cooling gives the lowest peak. In contrast to polypropylene homopolymers, which show strong morphological changes developing from the center of a spherulite, copolymer specimens are uniformly crosshatched. The highest melting peak is related to an open crosshatched framework of primary lamellae, and the next lower peak is related to later forming subsidiary lamellae filling the intervening space. The origin and nature of these double peaks are discussed in terms of the fractional crystallization and the ensuing constraints placed on isothermal lamellar thickening as a result of the exclusion of the comonomer from the polypropylene lattice. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3318–3332, 2004
Structure, morphology, and crystallization process of isotactic polypropylene/hydrogenated hydrocarbon resin blends
Authors: Silvestre C. , Cimmino S. , Lin J. S.
Published: August 2004

The structure, morphology, and isothermal and nonisothermal crystallization of isotactic polypropylene/low‐molecular‐mass hydrocarbon resin blends (iPP/HR) (up to 20% in weight of HR) have been studied, using optical and electron microscopy, wide‐ and small‐angle X‐ray and differential scanning calorimetry. New structures and morphologies can be activated, using appropriate preparation and crystallization conditions and blend composition. For every composition and crystallization condition, iPP crystallizes in α‐form, with a spherulitic morphology. The size of iPP spherulites increases with resin content, whereas the long period decreases. In the range of crystallization temperatures investigated, HR modifies the birefringence of iPP spherulites, favoring the formation of radial lamellae and changing the ratio between tangential and radial lamellae. Spherulitic radial growth rates, overall crystallization rates, and melting temperatures are strongly affected by resin, monotonically decreasing with resin content. This confirms miscibility in the melt between the two components of the blends. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3368–3379, 2004
Charge renormalization of cylinders and spheres: Ion size effects
Authors: Borukhov Itamar
Published: August 2004

The effect of the counterion size on the degree of counterion condensation onto a cylindrical macroion and a spherical one in the absence of salt is studied theoretically within a modified Poisson–Boltzmann approach. We find that excluded volume interactions reduce the degree of condensation. Using a simple variational free energy we show that this reduction can be attributed to an effective increase in the macroion size due to the contribution of the condensed counterions. We also find that for a charged cylinder, the reduction in charge renormalization vanishes at infinite dilution because of the extended nature of the condensed layer. In contrast, excluded volume interactions can reduce the degree of charge renormalization of a sphere even at high dilutions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3598–3615, 2004
Exploring peptide energy landscapes: A test of force fields and implicit solvent models
Authors: Steinbach Peter J.
Published: August 2004

A biased Monte Carlo‐minimization/annealing conformational search was used to characterize five descriptions of the energy landscape for each of three model systems: the 20‐residue “trp‐cage” miniprotein, the 20‐residue “BS1” peptide, and the 17‐residue “U(1‐17)T9D” peptide. The EEF1 and SASA energy landscapes were studied as well as those defined by using the GB/ACE implicit water model with one of three protein force fields: CHARMM19, CHARMM22, and CHARMM22/CMAP. The lowest‐energy structures of the trp‐cage and BS1 peptides found for the EEF1 landscape have main‐chain root‐mean‐square deviations (rmsds) from the respective NMR structures of less than 2 Å; for U(1‐17)T9D, the deviation is less than 3 Å using EEF1. The main‐chain rmsd of the minimum‐energy trp‐cage conformation obtained for the GB/ACE/CHARMM22/CMAP landscape is less than 1 Å. However, this energy function strongly favored helical structures for the two peptides shown by NMR to form beta‐sheet structures. Brief annealing of the system following main‐chain conformational changes was found to enhance the exploration of low‐energy states. The thousands of simulations reported here suggest that the prediction of protein structure might be improved by the simultaneous use of a CMAP‐like description of the main chain and an EEF1‐like description of the solvent. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Conformational sampling and dynamics of membrane proteins from 10‐nanosecond computer simulations
Authors: Faraldo‐Gómez José D. , Forrest Lucy R. , Baaden Marc , Bond Peter J. , Domene Carmen , Patargias George , Cuthbertson Jonathan , Sansom Mark S.P.
Published: August 2004

In the current report, we provide a quantitative analysis of the convergence of the sampling of conformational space accomplished in molecular dynamics simulations of membrane proteins of duration in the order of 10 nanoseconds. A set of proteins of diverse size and topology is considered, ranging from helical pores such as gramicidin and small β‐barrels such as OmpT, to larger and more complex structures such as rhodopsin and FepA. Principal component analysis of the Cα‐atom trajectories was employed to assess the convergence of the conformational sampling in both the transmembrane domains and the whole proteins, while the time‐dependence of the average structure was analyzed to obtain single‐domain information. The membrane‐embedded regions, particularly those of small or structurally simple proteins, were found to achieve reasonable convergence. By contrast, extra‐membranous domains lacking secondary structure are often markedly under‐sampled, exhibiting a continuous structural drift. This drift results in a significant imprecision in the calculated B‐factors, which detracts from any quantitative comparison to experimental data. In view of such limitations, we suggest that similar analyses may be valuable in simulation studies of membrane protein dynamics, in order to attach a level of confidence to any biologically relevant observations. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Structural and dynamic effects of α‐Helix deletion in Sso7d: Implications for protein thermal stability
Authors: Merlino Antonello , Graziano Giuseppe , Mazzarella Lelio
Published: August 2004

Sso7d is a 62‐residue protein from the hyperthemophilic archaeon Sulfolobus solfataricus with a denaturation temperature close to 100°C around neutral pH. An engineered form of Sso7d truncated at leucine 54 (L54Δ) is significantly less stable, with a denaturation temperature of 53°C. Molecular dynamics (MD) studies of Sso7d and its truncated form at two different temperatures have been performed. The results of the MD simulations at 300 K indicate that: (1) the flexibility of Sso7d chain at 300 K agrees with that detected from X‐ray and NMR structural studies; (2) L54Δ remains stable in the native folded conformation and possesses an overall dynamic behavior similar to that of the parent protein. MD simulations performed at 500 K, 10 ns long, indicate that, while Sso7d is in‐silico resistant to high temperature, the truncated variant partially unfolds, revealing the early phases of the thermal unfolding pathway of the protein. Analysis of the trajectories of L54Δ suggests that the unzipping of the N‐terminal and C‐terminal β‐strands should be the first event of the unfolding pathway, and points out the regions more resistant to thermal unfolding. These findings allow one to understand the role played by specific interactions connecting the two ends of the chain for the high thermal stability of Sso7d, and support recent hypotheses on its folding mechanism emerged from site‐directed mutagenesis studies. Proteins 2004. © 2004 Wiley‐Liss, Inc.