bluuebunny/crossref_metadata_2025_split huggingface dataset:
Helical conformations of hexapeptides containing N‐terminus diproline segments
Authors: Kantharaju  , Raghothama Srinivasarao , Aravinda Subrayashastry , Shamala Narayanaswamy , Balaram Padmanabhan 
Published: January 2010

AbstractThe role of N‐terminus diproline segments in facilitating helical folding in short peptides has been investigated in a set of model hexapeptides of the type Piv‐Xxx‐Yyy‐Aib‐Leu‐Aib‐Phe‐OMe (Piv, pivaloyl). Nine sequences have been investigated with the following N‐terminus dipeptide segments: DPro‐Ala (4) and Pro‐ΨPro (5, Ψ, pseudoproline), Ala‐Ala (6), Ala‐Pro (7), Pro‐Ala (8), Aib‐Ala (9), Ala‐Aib (10). The analog sequences Piv‐Pro‐Pro‐Ala‐Leu‐Aib‐Phe‐OMe (2) and Piv‐Pro‐Pro‐Ala‐Aib‐Ala‐Aib‐OMe (3) have also been studied. Solid state conformations have been determined by X‐ray crystallography for peptides 4, 6, and 8 and compared with the previously determined crystal structure of peptide 1 (Boc‐Pro‐Pro‐Aib‐Leu‐Aib‐Val‐OMe); (Rai et al., JACS 2006, 128, 7916–7928). Peptides 1 and 6 adopt almost identical helical conformations with unfolding of the helix at the N‐terminus Pro (1) residue. Peptide 4 reveals the anticipated DPro‐Ala type II' β‐turn, followed by a stretch of 310‐helix. Peptide 8 adopts a folded conformation stabilized by four successive 4→1 intramolecular hydrogen bonds. Ala (2) adopts an αL conformation, resulting in a type II β‐turn conformation followed by a stretch of 310‐helix. Conformational properties in solution were probed using solvent perturbation of NH chemical shifts which permit delineation of hydrogen bonded NH groups and nuclear Overhauser effects (NOEs) between backbone protons, which are diagnostic of local residue conformations. The results suggest that, continuous helical conformations are indeed significantly populated for peptides 2 and 3. Comparison of the results for peptides 1 and 2, suggest that there is a significant influence of the residue that follows diproline segments in influencing backbone folding. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 94: 360–370, 2010.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
ASIC verification: Integrating formal verification with HDL‐based courses
Authors: Massoumi Mehran , Sagahyroon Assim 
Published: January 2010

AbstractThe rapid progress of chip fabrication technology has paved the way to the design of complex ASICs containing several million transistors. According to published work, verification of these ASICs has emerged as a major bottleneck consuming up to three‐quarters of total pre‐silicon resources. This fact has tempted the scientific community to propose alternatives to the classical simulation approach. Recently, formal verification techniques have gained large attention and are becoming a key component in reducing the verification effort required to meet compressed design cycle times. In addition to the reliability factor, these techniques are proven to be cost effective since they help in reducing time allocated for test bench creation which is typically a time consuming and error prone activity. In this paper the formal or static approach is presented in a context that encourages its integration into HDL‐based courses at the senior or first year graduate level. Advantages of the static approach will be discussed by presenting property formulation for selected RTL designs. Moreover, the property language Property Specification Language (PSL), IEEE standard 1850, will be used in presenting property formulations. System Verilog Assertions (SVA) is another viable option for property specification and can be readily substituted for PSL. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 269–276, 2010; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20252
On the Mechanism of Action of Fullerene Derivatives in Superoxide Dismutation
Authors: Osuna Sílvia , Swart Marcel , Solà Miquel 
Published: January 2010

AbstractWe have studied the mechanism of the antioxidant activity of C60 derivatives at the BP86/TZP level with inclusion of solvent effects (DMSO) by using the COSMO approach. The reaction studied here involves degradation of the biologically relevant superoxide radical (O2.−), which is linked to tissue damage in several human disorders. Several fullerene derivatives have experimentally been shown to be protective in cell culture and animal models of injury, but precisely how these compounds protect biological systems is still unknown. We have investigated the activity of tris‐malonyl C60 (also called C3), which efficiently removes the superoxide anion with an activity in the range of several biologically effective, metal‐containing superoxide dismutase mimetics. The antioxidant properties of C3 are attributed to the high affinity of C60 to accept electrons. Our results show that once the superoxide radical is in contact with the surface of C3, its unpaired electron is transferred to the fullerene. This process, which converts the damaging O2.− to neutral oxygen O2, is the rate‐determining step of the reaction. Afterwards, another superoxide radical reacts with C3.− to form hydrogen peroxide and in the process takes up the additional electron that was transferred in the first step. The overall process is clearly exothermic and, in general, involves reaction steps with relatively low activation barriers. The capability of C3 to degrade a highly reactive oxygen species that is linked to several human diseases is of immediate interest for future applications in the field of biology and medicine.
Highly Uniform YBO3 Hierarchical Architectures: Facile Synthesis and Tunable Luminescence Properties
Authors: Jia Guang , You Hongpeng , Liu Kai , Zheng Yuhua , Guo Ning , Jia Junjiao , Zhang Hongjie 
Published: January 2010

AbstractHighly uniform pancake‐like YBO3 hierarchical architectures have been successfully prepared by a designed two‐step hydrothermal method. Yttrium precursor microprisms were first synthesized according to a simple hydrothermal route. Subsequently, nearly monodisperse multilayered YBO3 products with a pancake‐like shape were synthesized at the expense of the precursor during the hydrothermal process. The whole process was carried out under aqueous conditions without the use of any organic solvent, surfactant, or catalyst. The conversion process from the precursor to YBO3 products has been investigated by time‐dependent XRD experiments. Extending this method, other LnBO3 (Ln=Ho, Er, Tm, Yb) samples with well‐defined shape and dimensionality have also been obtained by a similar synthetic process. The luminescence colors of YBO3 samples co‐doped with Eu3+ and Tb3+ under ultraviolet or low‐voltage electron beam excitation can be tuned from red, through yellow and green‐yellow, to green by simply adjusting the relative doping concentrations of the activator ions. This merit of multicolor emissions in the visible region endows materials of this kind with potential application in the fields of light‐display systems and optoelectronic devices.
Experiments in the Chemistry Teacher Training Program
Authors: Janzen Margot , Wentorf Wilfried 
Published: January 2010

AbstractDie Diskussion zur Professionalisierung der Lehrerbildung war der Auslöser für eine kritische Überprüfung des an der Universität Kiel im Rahmen der Chemielehrerausbildung durchgeführten Unterrichtsversuche‐Praktikums für die Sekundarstufe I. Als Aufgabenfelder für eine Neugestaltung wurde die stärkere Einbindung fachdidaktischer Fragestellungen, die Berücksichtigung berufsorientierter Handlungskompetenzen und die Gestaltung und Reflexion von Lehr‐Lern‐Prozessen identifiziert. Daraus wurden drei Module entwickelt, die während des Praktikumszeitraumes aufeinander aufbauend durchgeführt wurden. Die im Folgenden vorgestellte Konzeption des Praktikums wird seit Wintersemester 2006/2007 durchgeführt.
Should all patients with melanoma between 1 and 2 mm Breslow thickness undergo sentinel lymph node biopsy?
Authors: Mays Michael P. , Martin Robert C. G. , Burton Alison , Ginter Brooke , Edwards Michael J. , Reintgen Douglas S. , Ross Merrick I. , Urist Marshall M. , Stromberg Arnold J. , McMasters Kelly M. , Scoggins Charles R. 
Published: January 2010

AbstractBACKGROUND:Sentinel lymph node (SLN) biopsy generally is recommended for patients who have melanoma with a Breslow thickness ≥1 mm. Most patients with melanoma between 1 mm and 2 mm thick have tumor‐negative SLNs and an excellent long‐term prognosis. The objective of the current study was to evaluate prognostic factors in this subset of patients and determine whether all such patients require SLN biopsy.METHODS:Patients with melanoma between 1 mm and 2 mm in Breslow thickness were evaluated from a prospective multi‐institutional study of SLN biopsy for melanoma. Disease‐free survival (DFS) and overall survival (OS) were evaluated by Kaplan‐Meier analysis to compare patients with melanoma that measured from 1.0 mm to 1.59 mm (Group A) versus patients with melanoma that measured from ≥1.6 mm to 2.0 mm thick (Group B). Univariate and multivariate analyses were performed to evaluate factors predictive of tumor‐positive SLN status, DFS, and OS.RESULTS:The current analysis included 1110 patients with a median follow‐up of 69 months. SLN status was tumor‐positive in 133 of 1110 patients (12%) including 66 of 762 patients (8.7%) in Group A and 67 of 348 patients (19.3%) in Group B (P < .0001). On multivariate analysis, age, Breslow thickness, and lymphovascular invasion were independently predictive of a tumor‐positive SLN (P < .05). DFS (P < .0001) and OS (P = .0001) were significantly better for Group A than for Group B. When tumor thickness was treated as either a continuous variable (P < 0.0001) or a categorical variable (P < .0001), it was significantly predictive of DFS and OS. On multivariate analysis, Breslow thickness, age, ulceration, histologic subtype, regression, Clark level, and SLN status were significant factors predicting DFS; and Breslow thickness, age, primary tumor location, sex, ulceration, and SLN status were significant factors predicting OS (P < .05). A subgroup of patients who had tumors <1.6 mm in Breslow thickness, had no lymphovascular invasion, and were aged ≥59 years had a low risk (5%) of tumor‐positive SLN.CONCLUSIONS:The current findings indicated that there is significant diversity in the biologic behavior of melanoma between 1 mm and 2 mm in Breslow thickness. SLN biopsy is recommended for all such patients to identify those with lymph node metastasis who are at the greatest risk of recurrence and mortality. Cancer 2010. © 2010 American Cancer Society.
5‐Aminolevulinic acid is a promising marker for detection of anaplastic foci in diffusely infiltrating gliomas with nonsignificant contrast enhancement
Authors: Widhalm Georg , Wolfsberger Stefan , Minchev Georgi , Woehrer Adelheid , Krssak Martin , Czech Thomas , Prayer Daniela , Asenbaum Susanne , Hainfellner Johannes A. , Knosp Engelbert 
Published: January 2010

AbstractBACKGROUND:Because of intratumoral heterogeneity, diffusely infiltrating gliomas that lack significant contrast enhancement on magnetic resonance imaging are prone to tissue sampling error. Subsequent histologic undergrading may delay adjuvant treatments. 5‐Aminolevulinic acid (5‐ALA) leads to accumulation of fluorescent porphyrins in malignant glioma tissue, and is currently used for resection of malignant gliomas. The aim of this study was to clarify whether 5‐ALA might serve as marker for visualization of anaplastic foci in diffusely infiltrating gliomas with nonsignificant contrast enhancement for precise intraoperative tissue sampling.METHODS:5‐ALA was administered in 17 patients with diffusely infiltrating gliomas with nonsignificant contrast enhancement. During glioma resection, positive fluorescence was noted by a modified neurosurgical microscope. Intraoperative topographic correlation of focal 5‐ALA fluorescence with maximum 11C‐methionine positron emission tomography uptake (PETmax) was performed. Multiple tissue samples were taken from areas of positive and/or negative 5‐ALA fluorescence. Histopathological diagnosis was established according to World Health Organization (WHO) 2007 criteria. Cell proliferation was assessed for multiregional samples by MIB‐1 labeling index (LI).RESULTS:Focal 5‐ALA fluorescence was observed in 8 of 9 patients with WHO grade III diffusely infiltrating gliomas. All 8 of 8 WHO grade II diffusely infiltrating gliomas were 5‐ALA negative. Focal 5‐ALA fluorescence correlated topographically with PETmax in all patients. MIB‐1 LI was significantly higher in 5‐ALA–positive than in nonfluorescent areas within a given tumor.CONCLUSIONS:The data indicate that 5‐ALA is a promising marker for intraoperative visualization of anaplastic foci in diffusely infiltrating gliomas with nonsignificant contrast enhancement. Unaffected by intraoperative brain shift, 5‐ALA may increase the precision of tissue sampling during tumor resection for histopathological grading, and therefore optimize allocation of patients to adjuvant treatments. Cancer 2010. © 2010 American Cancer Society.
Mucinous but not clear cell histology is associated with inferior survival in patients with advanced stage ovarian carcinoma treated with platinum‐paclitaxel chemotherapy
Authors: Bamias Aristotle , Psaltopoulou Theodora , Sotiropoulou Maria , Haidopoulos Dimitrios , Lianos Evangelos , Bournakis Evangelos , Papadimitriou Christos , Rodolakis Alexandros , Vlahos George , Dimopoulos Meletius A. 
Published: January 2010

AbstractBACKGROUND:Mucinous and clear cell histology have been associated with adverse prognosis in ovarian carcinomas. The authors compared the outcome of these subtypes with that of serous tumors in patients who were treated with combination paclitaxel/platinum at their center.METHODS:Four hundred twenty patients with histologically confirmed, serous (n = 367), mucinous (n = 24), or clear cell (n = 29) ovarian carcinomas, International Federation of Gynecology and Obstetrics stage III or IV disease, and who were treated with paclitaxel/platinum after cytoreductive surgery were included in this analysis.RESULTS:The median overall survival for each histological subtype was 47.7 months (95% confidence interval [CI], 37.7‐57.7 months) for serous, 15.4 months (95% CI, 4.2‐26.6 months) for mucinous, and 36.6 months (95% CI, 22.7‐50.5 months) for clear cell carcinomas. Cox regression analysis showed that mucinous histology was an independent predictor of poor prognosis compared with serous tumors (hazard ratio, 0.360; 95% CI, 0.215‐0.603; P = .001). In contrast, such a difference between clear cell and serous carcinomas was not found (P = .337). Median survival of patients with mucinous tumors and residual disease >2 cm was poor, averaging 7.1 months (95% CI, 4.6‐9.6 months).CONCLUSIONS:Mucinous but not clear cell histology is associated with significantly worse prognosis in advanced ovarian cancer treated with combination platinum/paclitaxel. Different therapeutic strategies should be studied in this entity. Cancer 2010. © 2010 American Cancer Society.
Weekly docetaxel, cisplatin, and 5‐fluorouracil as initial therapy for patients with advanced gastric and esophageal cancer
Authors: Overman Michael J. , Kazmi Syed M. , Jhamb Jagriti , Lin E , Yao James C. , Abbruzzese James L. , Ho Linus , Ajani Jaffer , Phan Alexandria 
Published: January 2010

AbstractBACKGROUND:Docetaxel, cisplatin, and 5‐flurouracil (DCF) administered every 3 weeks produces a high rate of treatment‐related adverse events. The objective of the current study was to evaluate the efficacy and tolerability of a weekly formulation of DCF.METHODS:Data from 117 patients treated at The University of Texas M. D. Anderson Cancer Center from 2002 to 2006 with a weekly formulation of DCF were retrospectively collected. A total of 95 patients received front‐line therapy with 20 mg/m2 of cisplatin, 350 mg/m2 of 5‐fluorouracil, and 20 mg/m2 of docetaxel administered once weekly for 6 consecutive weeks followed by a 2‐week break.RESULTS:Ninety‐five patients (median age, 62 years [range, 33 to 87 years], with an Eastern Cooperative Oncology Group performance status of 1 or 2 in 67%) received a median of 10 weeks of DCF treatment (range, 3‐41 weeks). Grade 3 or 4 hematologic toxicity (assessed according to National Cancer Institute Common Toxicity Criteria [version 3.0]) included granulocytopenia (4 patients) and anemia (9 patients). None of the patients developed a febrile neutropenic infection, but grade 3 or 4 non‐neutropenic infections occurred in 8 patients. Eighty patients had measurable disease with an objective response rate determined by Response Evaluation Criteria in Solid Tumors (RECIST) criteria of 34% (95% confidence interval [95% CI], 24‐45%). The median follow‐up was 9 months, with a median time to disease progression of 4.1 months (95% CI, 3.6‐5.7 months) and a median overall survival of 8.9 months (95% CI, 7.7‐10.8 months).CONCLUSIONS:In patients with advanced gastric and esophageal cancer who were not candidates for every‐3‐week DCF, a weekly formulation of DCF demonstrated modest activity with minimal hematologic toxicity, suggesting that weekly DCF is a reasonable treatment option for such patients. Cancer 2010. © 2010 American Cancer Society.
Investigations of impurity striations in potassium bichromate crystals
Authors: Szurgot M. 
Published: January 2010

AbstractImpurity striations in potassium bichromate crystals (KBC, lopezite) formed during crystal growth from aqueous solution were revealed by chemical etching and analyzed. Striations were revealed as etch grooves, as rows of dislocation etch pits and as rows of flat‐bottomed etch pits. Various types and groups of striations have been visualized. Some striations were due to lateral segregation of impurities caused by convection flow of the mother solution, other were formed during growth stoppages whereas induced striations were generated by changes in hydrodynamical conditions. Growth rates changes resulted in zonal distribution of impurities, formation of planar lattice strain, rows of clusters of point defects and rows of dislocations. Generation of striations with different intensities in various sectors is a proof of the selective capture of impurities. Ratios of growth rates of various faces of KBC crystals growing in forced and free convection regimes were determined by induced striations. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The influence of concentration and supersaturation ratio of CuI·HI on CuI crystal growth by decomplexation method
Authors: Gu Mu , Gao Pan , Liu Xiao‐Lin , Huang Shi‐Ming , Liu Bo , Ni Chen , Xu Rong‐Kun , Ning Jia‐Min 
Published: January 2010

AbstractThe fundamental role of solubility and supersaturation of solute for crystal growth from solution has been widely realized. In order to optimize the process of CuI crystal growth by CuI·HI decomplexation in HI acid, the solubility and supersaturation curves of CuI in HI‐H2O mixed solvent were measured, and then a modified concentration programming scheme was designed, which could grow high quality CuI single crystals of 2.5 mm on edge successfully. In this scheme, the concentration distribution of CuI·HI complex and HI acid in silica gel along their diffused direction were measured with spectrophotometer, and the evolution of CuI·HI complex supersaturation ratio was analysed. It was found that the excess CuI·HI complex concentration would lead to the high supersaturation ratio and the formation CuI dendrites. The condition for regular CuI single crystal growth in silica gel was measured as follow: when the crystal nuclei appears, the CuI·HI complex concentration in HI‐H2O solvent should be kept in the range of 0.033–0.050 mol/L and its corresponding supersaturation ratio is 1.24–1.45, and then they should be respectively declined to a range of 0.025–0.033 mol/L and 1.14–1.26 at the stage of crystal growth. The results may provide a useful clue for further improvement of the experimental scheme. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Development of criteria for the detection of adrenosterone administration by gas chromatography‐mass spectrometry and gas chromatography‐combustion‐isotope ratio mass spectrometry for doping control
Authors: Brooker Lance , Parr Maria Kristina , Cawley Adam , Flenker Ulrich , Howe Christopher , Kazlauskas Rymantas , Schänzer Wilhelm , George Adrian 
Published: January 2010

AbstractAdrenosterone (androst‐4‐ene‐3,11,17‐trione, 11‐oxoandrostenedione) is an endogenous steroid hormone that has been promoted as a dietary supplement capable of reducing body fat and increasing muscle mass. It is proposed that adrenosterone may function as an inhibitor of the 11β‐hydroxysteroid dehydrogenase type 1 enzyme (11β‐HSD1), which is primarily responsible for reactivation of cortisol from cortisone. The urinary metabolism of adrenosterone was investigated, after a single oral administration in two male subjects, by gas chromatography‐mass spectrometry (GC‐MS) and gas chromatography‐combustion‐isotope ratio mass spectrometry (GC‐C‐IRMS). Substantially increased excretion of 11β‐hydroxyandrosterone, 11β‐hydroxyetiocholanolone, 11‐oxoandrosterone and 11‐oxoetiocholanolone was observed. Minor metabolites such as 3α,17β‐dihydroxy‐5β‐androstan‐11‐one, 3α‐hydroxyandrost‐4‐ene‐11,17‐dione and 3α,11β‐dihydroxyandrost‐4‐en‐17‐one were also identified. The exogenous origin of the most abundant adrenosterone metabolites was confirmed by GC‐C‐IRMS according to World Anti‐Doping Agency criteria. Through analysis of a reference population data set obtained from urine samples provided by elite athlete volunteers (n = 85), GC‐MS doping control screening criteria are proposed:

11β‐hydroxyandrosterone concentration greater than 10 000 ng/mL (specific gravity adjusted to 1.020) or

11β‐hydroxyandrosterone/11β‐hydroxyetiocholanolone ratio greater than 20.

Urine samples fulfilling these screening criteria may be subjected to GC‐C‐IRMS analysis for confirmation of adrenosterone administration. Copyright © 2010 John Wiley & Sons, Ltd.
Pbx1 is essential for growth of zebrafish swim bladder
Authors: Teoh Pick‐Har , Shu‐Chien Alexander Chong , Chan Woon‐Khiong 
Published: January 2010

Abstractpbx1, a TALE (three–amino acid loop extension) homeodomain transcription factor, is involved in a diverse range of developmental processes. We examined the expression of pbx1 during zebrafish development by in situ hybridization. pbx1 transcripts could be detected in the central nervous system and pharyngeal arches from 24 hpf onwards. In the swim bladder anlage, pbx1 was detected as early as 28 hpf, making it the earliest known marker for this organ. Morpholino‐mediated gene knockdown of pbx1 revealed that the swim bladder failed to inflate, with eventual lethality occurring by 8 dpf. The knockdown of pbx1 did not perturb the expression of prdc and foxA3, with both early swim bladder markers appearing normally at 36 and 48 hpf, respectively. However, the expression of anxa5 was completely abolished by pbx1 knockdown at 60 hpf suggesting that pbx1 may be required during the late stage of swim bladder development. Developmental Dynamics 239:865–874, 2010. © 2010 Wiley‐Liss, Inc.