bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supramolecular Self‐Organization of “Janus‐like” Diblock Codendrimers: Synthesis, Thermal Behavior, and Phase Structure Modeling
Authors: Bury Izabela , Heinrich Benoît , Bourgogne Cyril , Guillon Daniel , Donnio Bertrand 
Published: August 2006

AbstractWe report on the design and synthesis of three series of segmented amphiphilic block codendrimers, and on their self‐organizing behavior in liquid‐crystalline mesophases. Connecting two prefunctionalized monodendrons, each differing in their chemical constitution and generation number, yielded these diblock supermolecules. One wedge of the codendrimer was made hydrophobic, and is based on a branched poly(benzyl ether) monodendron functionalized at the periphery by lipophilic aliphatic fragments (also known as Percec dendrons). The other segment was made hydrophilic by the grafting of hydroxyl‐containing moieties onto the focal functions of the former dendrons. Both types of dendrons were prepared independently by convergent methods and then joined in the ultimate stage of the synthetic procedure by cross‐coupling reactions. In this way, the proportion of the dendritic blocks was varied independently to allow control of the hydrophilic/hydrophobic balance (HHB), the hydrogen‐bonding ability, and consequently the capacity to tune the mesomorphic properties of the resulting “superamphiphiles” was anticipated. Essentially all the dendritic compounds display a thermotropic mesomorphism directly at or near room temperature as determined by using X‐ray diffraction, polarized optical microscopy, and differential scanning calorimetry. The nature and the supramolecular organization of the mesophases, namely columnar and cubic phases, are correlated to the size of the respective block monodendrons and the chemical structures of the dendromesogens. The molecular organization within the cubic phases can be geometrically described and well understood by the space‐filling polyhedron model.
The Molecular Basis of Self‐Assembly of Dendron–Rod–Coils into One‐Dimensional Nanostructures
Authors: Zubarev Eugene R. , Sone Eli D. , Stupp Samuel I. 
Published: August 2006

AbstractWe describe here a comprehensive study of solution and solid‐state properties of self‐assembling triblock molecules composed of a hydrophilic dendron covalently linked to an aromatic rigid rod segment, which is in turn connected to a hydrophobic flexible coil. These dendron–rod–coil (DRC) molecules form well‐defined supramolecular structures that possess a ribbonlike morphology as revealed by transmission‐electron and atomic‐force microscopy. In a large variety of aprotic solvents, the DRC ribbons create stable networks that form gels at concentrations as low as 0.2 % by weight DRC. The gels are thermally irreversible and do not melt at elevated temperatures, indicating high stability as a result of strong noncovalent interactions among DRC molecules. NMR experiments show that the strong interactions leading to aggregation involve mainly the dendron and rodlike blocks, whereas oligoisoprene coil segments remain solvated after gelation. Small‐angle X‐ray scattering (SAXS) profiles of different DRC molecules demonstrate an excellent correlation between the degree‐of‐order in the solid‐state and the stability of gels. Studies on two series of analogous molecules suggest that self‐assembly is very sensitive to subtle structural changes and requires the presence of at least four hydroxyl groups in the dendron, two biphenyl units in the rod, and a coil segment with a size comparable to that of the rodlike block. A detailed analysis of crystal structures of model compounds revealed the formation of stable one‐dimensional structures that involve two types of noncovalent interactions, aromatic π–π stacking and hydrogen bonding. Most importantly, the crystal structure of the rod–dendron compound shows that hydrogen bonding not only drives the formation of head‐to‐head cyclic structures, but also generates multiple linkages between them along the stacking direction. The cyclic structures are tetrameric in nature and stack into ribbonlike objects. We believe that DRC molecules utilize the same arrangement of hydrogen bonds and stacking of aromatic blocks observed in the crystals, explaining the exceptional stability of the nanostructures in extremely dilute solutions as well the thermal stability of the gels they form. This study provides mechanistic insights on self‐assembly of triblock molecules, and unveils general strategies to create well‐defined one‐dimensional supramolecular objects.
Ligand‐Based Virtual Screening, Parallel Solution‐Phase and Microwave‐Assisted Synthesis as Tools to Identify and Synthesize New Inhibitors of Mycobacterium tuberculosis
Authors: Manetti Fabrizio , Magnani Matteo , Castagnolo Daniele , Passalacqua Laura , Botta Maurizio , Corelli Federico , Saddi Manuela , Deidda Delia , De Logu Alessandro 
Published: August 2006

AbstractIn an attempt to identify new inhibitors of the growth of Mycobacterium tuberculosis (MTB), the causative agent of tuberculosis, a procedure for the generation, design, and screening of a ligand‐based virtual library was applied. This used both an in silico protocol centered on a recursive partitioning (RP) model described herein, and a pharmacophoric model for antitubercular agents previously generated by our research group. Two candidates emerged from databases of commercially available compounds, both characterized by a minimum inhibitory concentration (MIC) of 25 μg mL−1. Based on these compounds, two series of derivatives were synthesized by both parallel solution‐phase and microwave‐assisted synthesis, leading to enhanced antimycobacterial activity. During both the design and synthesis, attention was focused on the efficient allocation of available resources with the aim of reducing the overall costs associated with calculation and synthesis.
Treatment of pregnant breast cancer patients and outcomes of children exposed to chemotherapy in utero
Authors: Hahn Karin M.E. , Johnson Peter H. , Gordon Nancy , Kuerer Henry , Middleton Lavinia , Ramirez Mildred , Yang Wei , Perkins George , Hortobagyi Gabriel N. , Theriault Richard L. 
Published: August 2006

AbstractBACKGROUNDAs women in the US delay childbearing, it has been hypothesized that the incidence of breast cancer diagnosed during pregnancy will increase. There are very little prospective data on the treatment of pregnant women with breast cancer with chemotherapy and even less data on the outcomes of their children who were exposed to chemotherapy in utero.METHODSFifty‐seven pregnant breast cancer patients were treated on a single‐arm, multidisciplinary, institutional review board‐approved protocol with FAC (5‐fluorouracil, doxorubicin, cyclophosphamide) in the adjuvant (n = 32) or neoadjuvant (n = 25) setting. Parents/guardians were surveyed by mail or telephone regarding outcomes of children exposed to chemotherapy in utero.RESULTSOf the 57 women, 40 are alive and disease‐free, 3 have recurrent breast cancer, 12 died from breast cancer, 1 died from other causes, and 1 was lost to follow‐up. Of the 25 patients who received neoadjuvant FAC, 6 had a pathologic complete response, whereas 4 had no tumor response to chemotherapy and eventually died from their disease. All women who delivered had live births. One child has Down syndrome and 2 have congenital anomalies (club foot; congenital bilateral ureteral reflux). The children are healthy and those in school are doing well, although 2 have special educational needs.CONCLUSIONSBreast cancer can be treated with FAC chemotherapy during the second and third trimesters without significant short‐term complications for the majority of children exposed to chemotherapy in utero. Longer follow‐up of the children is needed to evaluate possible late side effects such as impaired cardiac function and fertility. Cancer 2006. © 2006 American Cancer Society.
Metabolic syndrome and growth hormone deficiency in adult survivors of childhood acute lymphoblastic leukemia
Authors: Gurney James G. , Ness Kirsten K. , Sibley Shalamar D. , O'Leary Maura , Dengel Donald R. , Lee Joyce M. , Youngren Nancy M. , Glasser Stephen P. , Baker K. Scott 
Published: August 2006

AbstractBACKGROUND.The purpose of the study was to determine the prevalence of metabolic syndrome, growth hormone deficiency, and cardiovascular risk factors among adult survivors of childhood acute lymphoblastic leukemia (ALL) treated with or without cranial irradiation.METHODS.Follow‐up was undertaken of 75 randomly selected long‐term childhood ALL survivors. Testing included fasting insulin, glucose, lipids, and growth hormone (GH) releasing hormone plus arginine stimulation test. The prevalence of metabolic syndrome was compared with population norms from 1999–2002 National Health and Nutrition Examination Study (NHANES) data, and internally between those with and without past cranial irradiation and those with normal (>16.5 μg/L) versus insufficient (9–16.5 μg/L) versus deficient (<9 μg/L) peak GH secretion.RESULTS.The mean subject age was 30 years and the mean time since ALL diagnosis was 25 years. The prevalence of metabolic syndrome did not differ statistically (P = .87) between study subjects (16.6%) and same‐age, same‐sex population norms (17.5%). However, 60% of subjects treated with cranial irradiation, compared with 20% of those who were not, had 2 or more of the 5 components of metabolic syndrome. Untreated abnormally low GH was present in 64% of subjects overall and 85% of those who received past cranial irradiation. Cranial irradiation was strongly related to GH deficiency, and in turn lower insulin‐like growth factor 1 (IGF‐1), higher fasting insulin, abdominal obesity, and dyslipidemia, particularly in women.CONCLUSIONS.Hematologists who treat childhood ALL patients, and particularly those who provide primary care to adult survivors, should be aware of the potential for long‐term GH deficiency and adverse cardiovascular and diabetes risk profiles as a consequence of leukemia treatment. Cancer 2006. © 2006 American Cancer Society.
Role of spinal MRI in the follow‐up of children treated for medulloblastoma
Authors: Bartels Ute , Shroff Manohar , Sung Lillian , Dag‐Ellams Ugo , Laperriere Normand , Rutka James , Bouffet Eric 
Published: August 2006

AbstractBACKGROUND.The purpose of the current study was to describe the usefulness of spinal magnetic resonance imaging (MRI) in children with medulloblastoma or primitive neuroectodermal tumor (PNET) of the posterior fossa.METHODS.Children consecutively diagnosed with medulloblastoma/PNET and followed in the Hospital for Sick Children/Toronto were identified. A homogenous cohort of children treated with craniospinal irradiation as part of their initial treatment was considered. Contrast‐enhanced spinal MRIs done concomitantly with cranial MRIs (doublets) were reviewed. Recurrence was defined as any new abnormal lesion (in the brain or in the spine) in symptomatic or asymptomatic patients. Doublets after the first recurrence were excluded in the final analysis. The utility of a spinal MRI in the presence of a negative cranial MRI was assessed.RESULTS.In all, 73 patients (21 females and 52 males; median age, 6.6 years, median follow‐up time, 4.3 years) had at least 1 evaluable doublet during the follow‐up period. Since concomitant cranial and spinal MRI was introduced as the standard evaluation for medulloblastoma/PNET in 1991, 286 doublets were evaluable. Fourteen spinal MRIs and 25 cranial MRIs showed new nodular or leptomeningeal lesions. In 2 patients, repeat MRIs ruled out recurrence (false‐positive). All confirmed spinal recurrences were associated with intracranial recurrence. Of 261 doublets with negative cranial MRI, no new lesion was identified on spinal MRI.CONCLUSIONS.An absence of progression on cranial MRI is highly predictive of absence of progression on spinal MRI. There is little evidence that surveillance spinal MRI (in children who underwent craniospinal radiation as part of their initial treatment) improves the detection of recurrences in children with medulloblastoma. Cancer 2006. © 2006 American Cancer Society.
Increased expression of avian erythroblastosis virus E26 oncogene homolog 1 in World Health Organization grade 1 meningiomas is associated with an elevated risk of recurrence and is correlated with the expression of its target genes matrix metalloproteinase‐2 and MMP‐9
Authors: Okuducu Ali Fuat , Zils Ulrich , Michaelis Silke A. M. , Mawrin Christian , von Deimling Andreas 
Published: August 2006

AbstractBACKGROUNDThe transcription factor avian erythroblastosis virus E26 (V‐Ets) oncogene homolog 1 (Ets‐1) is involved in tumor development and progression through the transcriptional regulation of several matrix‐degrading enzyme systems, including matrix metalloproteinases (MMPs). It has been demonstrated that the MMPs are expressed strongly in high‐grade meningiomas. To determine the biologic significance of Ets‐1 in the progression of benign meningiomas, the authors investigated the expressions of Ets‐1 and its target genes MMP‐2 and MMP‐9 in primary and recurrent, Grade 1 meningiomas.METHODSThe expression levels of Ets‐1, MMP‐2, and MMP‐9 were examined by immunohistochemistry in 70 Grade 1 meningiomas, including 36 primary tumors without recurrence after 5 years of follow‐up and 17 pairs of primary tumors and subsequent recurrences.RESULTSThe results demonstrated higher expression of Ets‐1, MMP‐2, and MMP‐9 proteins in meningiomas with subsequent recurrences compared with meningiomas from patients who had no recurrences (P < .001). In addition, Ets‐1 expression was correlated with the expression of both MMP‐2 and MMP‐9.CONCLUSIONSEts‐1 may be involved in meningioma recurrence by up‐regulating MMP‐2 and MMP‐9. Increased expression of these genes in World Health Organization grade 1 meningiomas may serve as an indicator for a high risk of recurrence. Cancer 2006. © 2006 American Cancer Society.
Relevance of extracapsular extension of pelvic lymph node metastasis in patients with bladder cancer treated in the contemporary era
Authors: Kassouf Wassim , Leibovici Dan , Luongo Tony , Munsell Mark F. , Vakar Funda , Dinney Colin P. , Grossman H. Barton , Kamat Ashish M. 
Published: August 2006

AbstractBACKGROUND.Previous reports have suggested that extracapsular extension (ECE) is a prognostic factor in patients with urothelial carcinoma who have positive lymph nodes at the time of radical cystectomy. In the current study, the relevance of ECE in patients treated in the contemporary era was evaluated.METHODS.A database search from 1993 to 2003 revealed 150 patients with pN+M0 disease detected after radical cystectomy; of these, 108 patients did not receive neoadjuvant chemotherapy and form the basis of the current report. Overall survival (OS), disease‐specific survival (DSS), and recurrence‐free survival (RFS) data were analyzed by the Kaplan‐Meier method, with log‐rank tests used to evaluate associations between survival and variables studied.RESULTS.Five‐year OS, DSS, and RFS rates were 30.9%, 45.5%, and 29.7%, respectively. Adjuvant chemotherapy was administered to 70% of patients. On multivariate analysis, adjuvant chemotherapy was significantly associated with prolonged OS, DSS, and RFS (P ≤ .01). For patients overall and when stratified by pN status, the presence of ECE of lymph node metastasis was not found to be significantly associated with OS (P = .52), DSS (P = .43), or RFS (P = .83).CONCLUSIONS.The current study suggests that ECE is not an independent prognostic factor in a contemporary series of patients with positive lymph nodes at radical cystectomy. This might be reflective of a paradigm shift that encompasses the adoption of multimodal therapy. Cancer 2006. © 2006 American Cancer Society.
The Possibility of a Liquid Superconductor
Authors: Edwards Peter P. , Rao C. N. R. , Kumar N. , Alexandrov A. Sasha 
Published: August 2006

AbstractAll superconductors are solids in their superconducting state, this canonical electronic state of matter presently having only been observed well below the melting temperature of the solid. The discovery of high‐temperature superconductivity in cuprates has widened significantly our horizons of the theoretical understanding of the physical phenomenon. A number of observations point to the possibility that superconductors with a high superconducting transition temperature may not be conventional Bardeen–Cooper–Schrieffer (BCS) superconductors, but rather derive from the Bose–Einstein condensation of real‐space pairs. While BCS superconductors exist in the solid state (probably with the exception of metallic liquid hydrogen at ultrahigh pressures), we argue here that a superconducting charged Bose liquid may be found in a true liquid state of condensed matter at ambient pressure. An experimental scenario is outlined in fluid metal–ammonia solutions for stabilizing and observing a high‐temperature superconducting liquid (ca. 230 K) or at least a vitreous superconductor in the corresponding quenched solutions (ca. 160 K).
Gadolinium‐Based Mixed‐Metal Nitride Clusterfullerenes GdxSc3−xN@C80 (x=1, 2)
Authors: Yang Shangfeng , Kalbac Martin , Popov Alexey , Dunsch Lothar 
Published: August 2006

AbstractThe first gadolinium‐based mixed‐metal nitride clusterfullerenes GdxSc3−xN@C80 (I) (1, x=2; 2, x=1) have been successfully synthesized by the reactive gas atmosphere method and isolated facilely by recycling high‐performance liquid chromatography (HPLC). The sum yield of 1 and 2 is 30–40 times higher than that of Gd3N@C80 (I). Moreover, an enhanced relative yield of 2 over the Sc3N@C80 (I) is achieved under the optimized synthesis conditions. According to the UV/Vis/NIR spectroscopic characterization, 1 and 2 are both stable fullerenes with large optical band‐gaps while 1 has higher similarity to Gd3N@C80 (I) and 2 resembles Sc3N@C80 (I). The vibrational structures of 1 and 2 are studied by Fourier‐transform infrared (FTIR) spectroscopy as well as density functional theory (DFT) computations. In particular, the structures of the encaged GdxSc3−xN clusters within 1 and 2 are analyzed.
Anteroposterior patterning in the limb and digit specification: Contribution of mouse genetics
Authors: Robert Benoît , Lallemand Yvan 
Published: August 2006

AbstractThe limb has been a privileged object of investigation and reflection for scientists over the past two centuries and continues to provide a heuristic framework to analyze vertebrate development. Recently, accumulation of new data has significantly changed our view on the mechanisms of limb patterning, in particular along the anterior‐posterior axis. These data have led us to revisit the mode of action of the zone of polarizing activity. They shed light on the molecular and cellular mechanisms of patterning linked to the Shh‐Gli3 signaling pathway and give insights into the mechanism of activation of these cardinal factors, as well as the consequences of their activity. These new data are in good part the result of systematic Application of tools used in contemporary mouse molecular genetics. These have extended the power of mouse genetics by introducing mutational strategies that allow fine‐tuned modulation of gene expression, interchromosomal deletions and duplication. They have even made the mouse embryo amenable to cell lineage analysis that used to be the realm of chick embryos. In this review, we focus on the data acquired over the last five years from the analysis of mouse limb development and discuss new perspectives opened by these results. Developmental Dynamics 235:2337–2352, 2006. © 2006 Wiley‐Liss, Inc.
Endogenous bone morphogenetic protein antagonists regulate mammalian neural crest generation and survival
Authors: Anderson Ryan M. , Stottmann Rolf W. , Choi Murim , Klingensmith John 
Published: August 2006

AbstractWe demonstrate here that Chordin and Noggin function as bone morphogenetic protein (BMP) antagonists in vivo to promote mammalian neural crest development. Using Chrd and Nog single and compound mutants, we find that Noggin has a major role in promoting neural crest formation, in which Chordin is partially redundant. BMP signaling is increased in dorsal tissues lacking Noggin and is further increased when Chordin is also absent. The early neural crest domain is expanded with decreased BMP antagonism in vivo. Noggin and Chordin also regulate subsequent neural crest cell emigration from the neural tube. However, reduced levels of these BMP antagonists ultimately result in perturbation of neural crest cell derived peripheral nervous system and craniofacial skeletal elements. Such defects reflect, at least in part, a function to limit apoptosis in neural crest cells. Noggin and Chordin, therefore, function together to regulate both the generation and survival of neural crest cells in mammalian development. Developmental Dynamics 235:2507–2520, 2006. © 2006 Wiley‐Liss, Inc.
Kinetics of tamoxifen‐regulated Cre activity in mice using a cartilage‐specific CreERT to assay temporal activity windows along the proximodistal limb skeleton
Authors: Nakamura Eiichiro , Nguyen Minh‐Thanh , Mackem Susan 
Published: August 2006

AbstractCartilage differentiation occurs over a broad time range from early embryonic development, when the mesenchymal condensations that give rise to cartilage models for future bone first appear, and continuing through adult life, when there is ongoing maintenance of articular joint surfaces and re‐activation of cartilage formation after fracture. The chondrogenic response also figures in the pathogenesis of degenerative and inflammatory joint diseases. We have generated a transgenic line expressing tamoxifen‐dependent Cre recombinase that gives efficient recombination in the chondrogenic lineage, both during embryogenesis and postnatally, and provides a valuable tool for analysis of gene function selectively in chondrogenic cells using conditional genetic approaches. Because the cartilage model of the limb skeleton forms progressively in a proximodistal order during discrete, well‐defined time periods, evaluation of the spatial extent of tamoxifen‐induced recombination along the limb axis during these time windows has also enabled us to examine the pharmacokinetics of single‐dose tamoxifen injections during pregnancy. Developmental Dynamics 235:2603–2612, 2006. © 2006 Wiley‐Liss, Inc.
Electroporation and EGFP labeling of gastrulating quail embryos
Authors: Cui Cheng , Lansford Rusty , Filla Mike B. , Little Charles D. , Cheuvront Tracey J. , Rongish Brenda J. 
Published: August 2006

AbstractLabeling embryonic cells to trace their motion is a classical experimental approach with a host of techniques being used to mark live cells and tissues. Genetically engineered fluorescent protein vectors (DNA plasmids) are a recent technology well suited to time‐resolved studies of cellular motion in live embryos. DNA plasmids encoding fluorescent proteins can be introduced into cells using several methods, including electroporation, a technique used widely for analysis of tissue culture and embryonic cells. Here we describe a technique designed to introduce DNA plasmids into early gastrulation stage quail embryos, ex ovo. The method is effective, and with practice enables an investigator to direct the vectors to relatively confined regions of gastrulating embryos. The required electroporation chamber can be fabricated from common laboratory materials. We anticipate that using this method of labeling cells in a warm‐blooded embryo, during gastrulation, will be a fruitful means of studying subsequent embryogenesis. Developmental Dynamics 235:2802–2810, 2006. © 2006 Wiley‐Liss, Inc.