bluuebunny/crossref_metadata_2025 huggingface dataset:
Experiences of Applying a Blended Learning Approach to Teaching Optical Communication Systems
Authors: Abdalla H. , Soares A. J. Martins , Garrosini D. , Molinaro L. F.
Published: August 2012

Blended learning consists of the combination of e-learning and a traditional education approach, and is particularly suitable to the process of transitioning towards e-learning from traditional forms of learning and teaching. This paper describes the use of the blended learning model in a course entitled ‘Optical Communications’, given in the Electrical Engineering Department at the University of Brasilia, Brazil. Throughout the article, the authors will analyse technological solutions found for the different segments which make up the implemented teaching/learning environment and the main difficulties they came across in their bid to integrate new interactive technologies into the traditional educational process. Finally, the concrete experience of applying this methodology in the course will be discussed. A survey conducted at the end of the course showed that students were satisfied with the pedagogical approach. Concerning the main elements of the blend and its efficacy, the results indicate an overall positive assessment.
Teaching Fundamentals of Measurement-Based Load Modelling Approach through Practical Examples
Authors: Korunović L. M.
Published: August 2012

The paper presents a computer program designated for teaching load modelling fundamentals, answering an increasing need for education of electrical engineers in this area. The program is based on data obtained during numerous field tests that encompass voltage changes using on-load tap changers. In this way students apply a measurement-based load modelling approach and analyse load behaviour from many practical examples during voltage changes on different days of the week and over different time periods. The program allows future engineers to become familiar with some important fundamental issues of load modelling such as: identification of load model parameters, selection of proper load model, determination of representative load characteristics and adequacy of the usage of an approximate load model.
Dose Escalation with Proton Radiation Therapy for High-Grade Meningiomas
Authors: Chan A. W. , Bernstein K. D. , Adams J. A. , Parambi R. J. , Loeffler J. S.
Published: August 2012

Purpose of this study was to determine the toxicity and treatment outcome after dose escalation with proton radiation therapy for patients with World Health Organization (WHO) grade II and grade III meningiomas. Between 1997 and 1999, 6 patients with newly diagnosed or recurrent grade II or III meningioma were treated on a Phase I/II dose escalation trial with combined proton-photon radiotherapy at the Harvard Cyclotron Laboratory/Massachusetts General Hospital. The median age was 46. The sites were sphenoid wing in 2 patients, parasagittal/falcine in 2, parasellar in 1, and olfactory groove in 1. The median gross total volume (GTV) at the time of radiation was 13.3 cc (range: 4.0–129.5). The total dose to the GTV for the grade II and III meningiomas was 68.4 and 72.0 Gy (RBE) in 1.8 Gy (RBE), respectively. The median percentage of proton was 80%. All patients tolerated radiation treatment without any treatment break. None of the patients required steroids or hospitalization during radiation. There was no acute grade 3 to 5 toxicity. With a median follow-up period of 145 months for all surviving patients, one patient developed local recurrence. For the 5 patients with tumor controlled at the primary sites, 3 patients developed new meningioma(s) distantly from the primary sites at a median time of 25 months (range, 9–79). The median survival for grade II and grade III tumors was 145 months and 28 months, respectively. One patient developed late grade 1 dry eye. Two patients developed late grade 2 hypothyroidism and two developed grade 2 hypogonadism. There was no late grade 3–5 toxicity. Dose escalation with proton radiation therapy resulted in low toxicity and high local control rate in patients with high-grade meningiomas. Development of distant meningioma(s) intracranially was the main pattern of failure. Larger prospective studies are necessary to confirm our results.
Treatment Planning and Delivery Evaluation of Volumetric Modulated Arc Therapy for Stereotactic Body Radiotherapy of Spinal Tumours: Impact of Arc Discretization in Planning System
Authors: Marchand E. L. , Sahgal A. , Zhang T. J. , Millar B. A. , Sharpe M. , Moseley D. , Letourneau D.
Published: August 2012

The purpose of this study was to compare single arc volumetric modulated arc therapy (VMAT) to intensity modulated radiotherapy (IMRT) for spine SBRT in terms of target coverage, organ at risk (OAR) sparing and delivery performance. VMAT plans with 91 control points (VMAT-91CP) were generated for 15 spine metastases patients previously treated with a nine-field IMRT technique. VMAT and IMRT plans were compared based on target coverage, maximum spinal cord dose, maximum plan dose and volume of normal tissue receiving 20% to 80% of the prescribed dose. Treatment delivery time and monitor units (MU) were measured to determine delivery efficiency. To assess the impact of arc discretization in the treatment planning system (TPS), the VMAT-91CP plans were modified by almost doubling the number of CPs (VMAT-181CP). Planned-to-delivered dose agreement for both techniques was assessed using two types of 3D detector arrays. VMAT-91CP target coverage was equivalent to IMRT while maintaining or improving spinal cord sparing. This was achieved without increasing the volume of normal tissue receiving low or intermediate dose levels. Planned-to-delivered dose agreement equivalent to IMRT was achieved with VMAT, but required decreasing the CP angular spacing from 4° to 2° (VMAT-181CP plans). On average, VMAT-181CP plans reduced delivery time by 53% compared to IMRT. Single-arc VMAT for spine SBRT improved delivery efficiency while maintaining target coverage and OAR sparing compared to IMRT. VMAT plans generated with a CP gantry angular spacing of 2° is recommended to avoid a discretization effect in the TPS and ensure acceptable planned-to-delivered dose agreement.
In vivo Photoacoustic Tomography of Total Blood Flow and Potential Imaging of Cancer Angiogenesis and Hypermetabolism
Authors: Yao Junjie , Maslov Konstantin I. , Wang Lihong V.
Published: August 2012

Blood flow is a key parameter in studying cancer angiogenesis and hypermetabolism. Current photoacoustic blood flow estimation methods focus on either the axial or transverse component of the flow vector. However, the Doppler angle (beam-to-flow angle) is needed to calculate the total flow speed, and it cannot always be estimated accurately in practice, especially when the system's axial and lateral resolutions are different. To overcome this problem, we propose a method to compute the total flow speed and Doppler angle by combining the axial and transverse flow measurements. The method has been verified by flowing bovine blood in a plastic tube at various speeds and Doppler angles. The error was experimentally determined to be less than 0.3 mm/s for total flow speed, and less than 15° for the Doppler angle. In addition, the method was tested in vivo on a mouse ear. We believe that the proposed method has the potential to be used for cancer angiogenesis and hypermetabolism imaging.
Near-Infrared Center-of-Intensity Time Gated Imaging for Detection of a Target in a Highly Scattering Turbid Medium
Authors: Wang Yimin , Gayen S. K. , Alrubaiee M. , Alfano R. R.
Published: August 2012

A near-infrared optical imaging approach for locating a target embedded in a turbid medium is introduced. The target localization is based on an analysis of the spatial variation of the transmitted-light intensity distribution for illumination at different positions on the sample boundary. The approach is used to detect, locate and generate images of absorbing targets embedded inside model scattering media of thickness approximately 50 times the transport mean free path of the medium, as well as, of ex vivo biological tissue specimens.
Distribution of Phthalocyanines and Raman Reporters in Human Cancerous and Noncancerous Breast Tissue as Studied by Raman Imaging
Authors: Brozek-Pluska Beata , Jarota Arkadiusz , Jablonska-Gajewicz Joanna , Kordek Radzislaw , Czajkowski Wojciech , Abramczyk Halina
Published: August 2012

There is a considerable interest in the developing new diagnostic techniques allowing noninvasive tracking of the progress of therapies used to treat a cancer. Raman imaging of distribution of phthalocyanine photosensitizers may open new possibilities of Photodynamic Therapy (PDT) to treat a wide range of neoplastic lesions with improved effectiveness of treatment through precise identification of malignant areas. We have employed Raman imaging and Raman spectroscopy to analyze human breast cancer tissue that interacts with photosensitizers used in the photodynamic therapy of cancer. PCA (Principal Component Analysis) has been employed to analyze various areas of the noncancerous and cancerous breast tissues. The results show that the emission spectra combined with the Raman images are very sensitive indicators to specify the aggregation state and the distribution of phthalocyanines in the cancerous and noncancerous breast tissues. Our results provide experimental evidence on the role of aggregation of phthalocyanines as a factor of particular significance in differentiation of the normal and tumourous (cancerous or benign pathology) breast tissues. We conclude that the Raman imaging reported here has a potential to be a novel and effective photodynamic therapeutic method with improved selectivity for the treatment of breast cancer.
Macromolecular Changes in Nilotinib Resistant K562 Cells; an In vitro Study by Fourier Transform Infrared Spectroscopy
Authors: Ceylan Cagatay , Camgoz Aylin , Baran Yusuf
Published: August 2012

Nilotinib is a second generation tyrosine kinase inhibitor which is used in both first and second line treatment of chronic myeloid leukemia (CML). In the present work, the effects of nilotinib resistance on K562 cells were investigated at the molecular level using Fourier transform infrared (FT-IR) spectroscopy. Human K562 CML cells were exposed to step-wise increasing concentrations of nilotinib, and sub-clones of K562 cells resistant to 50 nM nilotinib were generated and referred to as K562/NIL-50 cells. Antiproliferative effects of nilotinib were determined by XTT cell proliferation assay. Changes in macromolecules in parental and resistant cells were studied by FT-IR spectroscopy. Nilotinib resistance caused significant changes which indicated increases in the level of glycogen and membrane/lipid order. The amount of unsaturated lipids increased in the nilotinib resistant cells indicating lipid peroxidation. The total amount of lipids did not change significantly but the relative proportion of cholesterol and triglycerides altered considerably. Moreover, the transcriptional status decreased but metabolic turn-over increased as revealed by the FT-IR spectra. In addition, changes in the proteome and structural changes in both proteins and the nucleus were observed in the K562/NIL-50 cells. Protein secondary structural analyses revealed that alpha helix structure and random coil structure decreased, however, anti-parallel beta sheet structure, beta sheet structure and turns structure increased. These results indicate that the FT-IR technique provides a method for analyzing drug resistance related structural changes in leukemia and other cancer types.
Correlation of Three Different Approaches of Small Bowel Delineation and Acute Lower Gastrointestinal Toxicity in Adjuvant Pelvic Intensity-Modulated Radiation Therapy for Endometrial Cancer
Authors: Chi Alexander , Nguyen Nam P. , Xu Jiahong , Ji Minghua , Tang Jinhai , Jin Jing , Ong Evan S. , Welsh James S.
Published: August 2012

We investigate in this study the approach of small bowel delineation that would best correlate with acute lower GI toxicity during adjuvant intensity-modulated radiation therapy (IMRT) for endometrial cancer in this study. Thirty-two endometrial cancer patients (FIGO IB-IVA) were treated with postoperative pelvic IMRT to 48.2 ± 3.1 Gy. The small bowel was delineated as separate loops, limited bowel space (BS), or an intestinal cavity (IC). The volume of the small bowel (VSB) in absolute volume or as the percentage of the total volume at various dose levels was obtained from the dose volume histograms (DVHs). Each patient's acute lower gastro-intestinal (GI) toxicity was assessed prospectively during the course of IMRT. After a median follow up of 19.6 months, the median survival, loco-regional control, progression-free-survival (PFS), and distant metastasis-free survival (DMFS) were 40.9 months, 81.2%, 62.5%, and 68.8%, respectively. Acute lower GI toxicity observed were of grade 0, 1, and 2 only: 34.4%, 31.2%, and 34.4%, respectively. The difference in %VSB with the small bowel delineated as IC at 45 Gy (%VSBIC45) between grade 2 and grade 0 acute lower GI toxicity reached statistical significance upon linear regression analysis ( p = 0.0347). Thus, the proportion of small bowel contoured as IC in the high dose region can potentially be an important predictor for acute lower GI toxicity during and after postoperative pelvic IMRT.
Adjustment of Ultrasound Exposure Duration to Microbubble Sonodestruction Kinetics for Optimal Cell Sonoporation In Vitro
Authors: Tamošiūnas M. , Jurkonis R. , Mir L. M. , Lukoševičius A. , Venslauskas M. S. , Šatkauskas S.
Published: August 2012

Cell sonoporation enables the delivery of various exogenous molecules into the cells. To maximize the percentage of reversibly sonoporated cells and to increase cell viability we propose a model for implicit dosimetry for adjustment of ultrasound (US) exposure duration. The Chinese hamster ovary cell suspension was supplemented with microbubbles (MB) and exposed to US, operating at the frequency of 880 kHz, with a 100% duty cycle and with an output peak negative pressure (PNP) of 500 kPa for durations ranging from 0.5 to 30 s. Using diagnostic B-scan imaging we showed that the majority of the MB at 500 kPa US peak negative pressure undergo sonodestruction in less than a second. During this time maximal number of reversibly sonoporated cells was achieved. Increase of US exposure duration did not increase sonoporated cell number, however it induced additional cell viability decrease. Therefore aiming to achieve the highest level of reversibly sonoporated cells and also to preserve the highest level of cell viability, the duration of US exposure should not exceed the duration needed for complete MB sonodestruction.
Comparative Proteome Analysis of Human Lung Squamous Carcinoma using Two Different Methods: Two-Dimensional Gel Electrophoresis and iTRAQ Analysis
Authors: Zeng Gu-Qing , Zhang Peng-Fei , Li Cui , Peng Fang , Li Mao-Yu , Xu Yan , Yu Feng-Lei , Chen Ming-Jiu , Yi Hong , Li Guo-Qing , Chen Zhu-Chu , Xiao Zhi-Qiang
Published: August 2012

Discovery of early-diagnosis biomarkers is the key to improve the early-diagnosis and prognosis of human lung squamous carcinoma (hLSC). In order to identify more exhaustive and systematic protein biomarkers for early-diagnosis of hLSC, we chose LCM purified cells from hLSC tissues and paired normal bronchial epithelia(NBE) tissues and used two methods, the classical 2-DE/MS approach and the new iTRAQ analysis. We found a total of 63 differential proteins, 22 proteins in 2-DE and 59 proteins in iTRAQ analysis, between hLSC and NBE tissues. Among them, 18 proteins were quantified using both methods. The expression level of 15 proteins (68.2%) in 2-DE was consistent with that in iTRAQ analysis. Series of proteins involved in cytoskeleton, chaperone, GTP binding, metabolic process, cell apoptosis, cell proliferation and differentiation, signal transduction, transcription and translation were identified, suggesting their possible role in the emergence of oncogenic pathways leading to carcinogenesis of hLSC. These proteins may make as potential biomarkers for diagnosis of hLSC. The two methods gave us closely related but different information about proteins, suggesting they are complementary or at least supplementary methods at present. Our results show both the usefulness of iTRAQ reagent technology for identification of further potential marker proteins as well as for prevalidation of biomarker.
Layered H2Ti6O13‐Nanowires: A New Promising Pseudocapacitive Material in Non‐Aqueous Electrolyte
Authors: Wang Yonggang , Hong Zhensheng , Wei Mingdeng , Xia Yongyao
Published: August 2012

Layered H2Ti6O13‐nanowires are prepared using a facile hydrothermal method and their Li‐storage behavior is investigated in non‐aqueous electrolyte. The achieved results demonstrate the pseudocapacitive characteristic of Li‐storage in the layered H2Ti6O13‐nanowires, which is because of the typical nanosize and expanded interlayer space. The as‐prepared H2Ti6O13‐nanowires have a high capacitance of 828 F g−1 within the potential window from 2.0 to 1.0 V (vs. Li/Li+). An asymmetric supercapacitor with high energy density is developed successfully using H2Ti6O13‐nanowires as a negative electrode and ordered mesoporous carbon (CMK‐3) as a positive electrode in organic electrolyte. The asymmetric supercapacitor can be cycled reversibly in the voltage range of 1 to 3.5 V and exhibits maximum energy density of 90 Wh kg−1, which is calculated based on the mass of electrode active materials. This achieved energy density is much higher than previous reports. Additionally, H2Ti6O13//CMK‐3 asymmetric supercapacitor displays the highest average power density of 11 000 W kg−1. These results indicate that the H2Ti6O13//CMK‐3 asymmetric supercapacitor should be a promising device for fast energy storage.
Protein Rebinding to a Surface‐Confined Imprint
Authors: Dechtrirat Decha , Jetzschmann Katharina J. , Stöcklein Walter F. M. , Scheller Frieder W. , Gajovic‐Eichelmann Nenad
Published: August 2012

A novel strategy to prepare a selective ultrathin molecularly imprinted polymer (MIP) film directly on the gold‐based transducer surface for the peptide and protein detection in aqueous solution is demonstrated using a combination of epitope‐ and electrochemical surface imprinting approach. The synthetic peptide derived from the surface‐exposed C‐terminus of cytochrome c (Cyt c, residues 96–104) is selected as the template for the imprinting. It is labeled with a fluorescent dye in order to quantitatively evaluate all stages of the imprinting process in terms of changes in mean fluorescence intensity. The labeled peptide template is first chemisorbed on the gold surface as an oriented submonolayer through an additional C‐terminal cysteine. After electropolymerization, the template is stripped off electrochemically. To allow the imprinted sites to be confined to the surface, the film thickness is controlled to be comparable to the thickness of the peptide layer. This is achieved by the electropolymerization of scopoletin. Recognition capabilities of the films are characterized and the resulting MIP film is able to selectively capture the template peptide and the corresponding target protein. In case of the peptide recognition, the MIP film can discriminate even the single amino acid mismatched sequences of the target peptide.
Modeling gas‐particle two‐phase flows with complex and moving boundaries using DEM‐CFD with an immersed boundary method
Authors: Guo Y. , Wu C. ‐Y. , Thornton C.
Published: August 2012

An immersed boundary method (IBM) has been developed and incorporated into the coupled discrete element method and computational fluid dynamics (DEM‐CFD) approach to model particulate systems consisting of a compressible gas and solid particles with complex and/or moving boundaries. The IBM is used to deal with the interaction between gas and complex and moving boundaries by using simple rectangular grids to discretize the fluid field. The developed method has been applied to simulate some typical powder handling processes (e.g., gas fluidization with an immersed tube, segregation in a vertically vibrated bed, and pneumatic conveying). Good agreement is achieved between the present simulation results and the experimental ones reported in the literature. It has been demonstrated that the capacity of DEM‐CFD is enhanced with the incorporation of IBM, which can be used to simulate a wide range of problems that could not be handled with the conventional DEM‐CFD method. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1075–1087, 2013
The differences and correlations of BCR‐ABL transcripts between peripheral blood and bone marrow assays are associated with the molecular responses in the bone marrow for chronic myelogenous leukemia
Authors: Jiang Qian , Zhao Xiang‐Yu , Qin Ya‐Zhen , Liu Yan‐Rong , Lai Yue‐Yun , Jiang Bin , Huang Xiao‐Jun
Published: August 2012

Previous studies concerning BCR‐ABL mRNA levels by quantitative real‐time RT‐PCR (Q‐PCR) for chronic myelogenous leukemia (CML) have shown a significant concordance between peripheral blood (PB) and bone marrow (BM) assays. The objective of this study was to determine whether molecular monitoring using PB was comparable to using BM for CML. A comparative study was performed that analyzed the Q‐PCR results of 712 simultaneous PB and BM samples from 330 patients before and during imatinib therapy. For the 78 paired pretreatment samples, the level of BCR‐ABL mRNA in PB was lower than that in BM (P = 0.007). Although the overall amounts of BCR‐ABL mRNA in the PB and BM were comparable (P= 0.072) and there was a strong correlation (r = 0.839, P < 0.001) with the 634 paired on‐treatment samples, the depth of the molecular response in PB was lower than that in BM (P < 0.001). The level of BCR‐ABL mRNA in PB was lower than that in BM where the BM BCR‐ABL mRNA < 1 log reduction (P < 0.001) or ≥ 1–< 2 log‐reductions (P = 0.008) from the baseline, and higher than that where the BM BCR‐ABL mRNA ≥ 2 log‐reductions (P < 0.001). A strong correlation (r = 0.811, P < 0.001) was only found where the BM BCR‐ABL mRNA < 1 log reduction. We conclude that the differences and correlations of BCR‐ABL mRNA between PB and BM assays depend on the depth of the molecular response in BM for CML during imatinib therapy. Am. J. Hematol., 2012. © 2012 Wiley Periodicals, Inc.
Olfactory outcomes following endoscopic pituitary surgery with or without septal flap reconstruction: a randomized controlled trial
Authors: Tam Samantha , Duggal Neil , Rotenberg Brian W.
Published: August 2012

Background

Postoperative hyposmia and anosmia is an often overlooked complication of endoscopic pituitary surgery. Septal flaps have been utilized as a strategy for repairing and preventing postoperative cerebrospinal fluid (CSF) leaks. The olfactory impact of raising this flap for sellar reconstruction and CSF repair needs qualitative assessment. This study aims to ascertain the effect of the Hadad‐Bassagasteguy (HB) flap on olfaction in endoscopic pituitary surgery.

Methods

In this randomized controlled trial, patients undergoing pituitary surgery underwent computerized randomization. Those in Group 1 all had HB flaps raised and placed for sellar floor defects. Those in Group 2 underwent reconstruction with synthetic or nonautologous materials. The University of Pennsylvania Smell Identification Test (UPSIT) was administered preoperatively and 6 months postoperatively. Results were analyzed using nonparametric tests.

Results

Twenty subjects were enrolled, 10 in each group. Eight subjects in Group 1 vs 3 in Group 2 had intraoperative CSF leak. All were repaired intraoperatively and none required additional intervention. Preoperatively, UPSIT scores were not significantly different between groups (p = 0.62). Preoperative vs postoperative comparisons were significant for a decrease in scores in both groups postoperatively (Group 1, p < 0.001; Group 2, p < 0.001). Those undergoing HB flap reconstruction had significantly worse scores postoperatively (p = 0.001).

Conclusion

Endoscopic pituitary surgery results in decreased olfaction with or without deploying a septal flap. However, use of the HB flap for reconstruction can worsen hyposmia at least 6 months after surgery. Olfaction should be considered when use of the HB flap is planned. © 2013 ARS–AAOA, LLC.
Pt‐IrO2nanorod array electrode for oxygen evolution in PEM water electrolysis cell
Authors: Ye Feng , Hu Weiwei , Liu Hui , Liu Jiangshan , Li Jianling , Wang Xindong , Yang Jun
Published: August 2012

Pt‐IrO2nanorod arrays supported on the carbon paper were fabricated directly using the dip‐coating/calcination method. The nanorod arrays and ordering were characterized by scanning electron microscope. Pt‐IrO2/carbon paper directly used as catalyst layer and support layer with the united structure on the anode side is demonstrated to have excellent electrocatalytic activity for oxygen evolution in proton exchange membrane (PEM) water electrolysis cell. By employing the Pt‐IrO2(Pt:Ir = 3:7) at anode and commercial 20% Pt/C catalysts at cathode, a cell voltage as low as 1.86 V was achieved under high current density with the total noble metal loading of 0.8 mg cm−2. The Pt‐IrO2electrocatalysts with uniform nanorod arrays structure, good conductivity are supposed to play a key role for their enhanced catalytic activity toward oxygen evolution reaction. The study in this work might open an opportunity for the efficient utilization of valuable catalytic materials in PEM water electrolysis by decreasing the catalyst loading and provide a facile route to fabricate electrode based on direct calcination of noble metal and metal oxide nanoparticles onto carbon paper. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
Properties of melt processable PTFE/PEEK blends: The effect of reactive compatibilization using electron beam irradiated melt processable PTFE
Authors: Frick Achim , Sich Dorota , Heinrich Gert , Lehmann D. , Gohs U. , Stern Claudia
Published: August 2012

For the first time, blends of melt processable polytetrafluoroethylene (MP PTFE) with polyetheretherketone (PEEK) in the MP PTFE/PEEK ratio of 100/0, 80/20, 50/50, 20/80, and 0/100 w/w were prepared and characterized. MP PTFE/PEEK blends are attractive materials due to the combination of low coefficient of friction and universal chemical resistance of MP PTFE with good wear resistance and mechanical strength of PEEK while maintaining high thermal stability of both. Miscibility, phase morphology, and mechanical properties of the new MP PTFE/PEEK blends were investigated. To improve their end‐use properties, an attempt of reactive compounding with the electron beam irradiated MP PTFE (e‐beam MP PTFE) was made. The reactive compounding was done in two steps, that is, the preparation of a masterbatch (MB) consisting of e‐beam MP PTFE/PEEK (50/50 w/w) and subsequent melt blending of MP PTFE/PEEK with varying concentrations of MB. The e‐beam irradiation of MP PTFE carried out in air atmosphere and at room temperature with a dose of 50 kGy results in its chain scission associated with formation of COF and COOH functional groups. Such modified MP PTFE can be used to compatibilize MP PTFE/PEEK blends. Reactive compatibilized blends exhibit improved phase morphology and mechanical properties. Especially for MP PTFE/PEEK 50/50 blends, a great improvement of almost 250% in strain at break, 40% in stress at break, and more than 600% in toughness was achieved. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Study on thermal and biodegradation resistance of tropical wood material composites
Authors: Hamdan Sinin , Islam Md. Saiful , Ahmed Abu Saleh , Rahman Md. Rezaur , Rusop Mohamad
Published: August 2012

Thermal stability and decay resistance properties of tropical wood polymer composites (WPCs) were investigated in this study. WPCs were prepared from several selected tropical wood species by impregnating the woods with methyl methacrylate (MMA) which was combined with a crosslinker, hexamethylene diisocyanate (HMDIC). The impregnation of wood with the monomer systems and polymerization were accomplished by vacuum‐pressure method. Thermal properties of manufactured WPC in terms of thermogravimetric analysis and differential scanning calorimetry were evaluated, and an improvement in thermal stability was found for fabricated WPC. The wood was then exposed to two types of fungi; white‐rot (polyporous versicolor) and brown‐rot (postia placenta), for 12 weeks. Decay was assessed through percentage (%) of weight loss. A significant improvement was found in the treated woods compared to the untreated ones. The improvement in properties was observed as more potential with the MMA/HMDIC combination. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Crystallization behavior of polybutadiene containing silica particles
Authors: Doan Vu Anh , Nobukawa Shogo , Ohtsubo Shigeki , Tada Toshio , Yamaguchi Masayuki
Published: August 2012

The effect of silica particles (silica), which are petroleum‐free products, on the isothermal and nonisothermal crystallizations of cis‐1,4‐poly(butadiene) rubber (BR) is investigated. DSC measurements reveal that silica accelerates the crystallization of BR. As a result, BR‐containing silica shows crystallization even after crosslinking reaction. Because of the enhanced crystallization, the tensile modulus is much higher than that without silica in the range between the glass transition temperature and the melting point. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Overview of loggerhead turtles coastal nets interactions in the Mediterranean Sea
Authors: Echwikhi Khaled , Jribi Imed , Bradai Mohamed Nejmeddine , Bouain Abderrahmen
Published: August 2012

In the Mediterranean Sea, trawl nets and drifting longlines have been recognized as methods that capture thousands or tens of thousands of turtles. However, the possible impact of other fishing methods has not been adequately addressed, especially for artisanal and amateur fisheries that use coastal nets.

Coastal net fisheries, including driftnets and set nets, used at a much shallower depth (<40 m) in the Mediterranean, result in a large bycatch of loggerhead turtles in the neritic zone. The mortality rate with these fisheries seems to be higher than with other commercial fisheries.

In the Mediterranean context, additional assessments on fishery characteristics and fishing gear parameters to: (i) develop a simple and unanimous definition of an artisanal fishery; and (ii) standardize units for reporting sea turtle bycatch with coastal nets, are needed to provide an understanding of the current relative degree of risk coastal net fisheries pose to turtle populations.

Mitigation measures based on (a) gear‐technology approaches, (b) fisheries closures, and (c) increased awareness and education of fishermen, must be considered as priorities and should be implemented without further delay. Copyright © 2012 John Wiley & Sons, Ltd.
Heterochronic Protein Expression Patterns in the Developing Embryonic Chick Cerebellum
Authors: Gilbert Ea , Lim Yh , Vickaryous Mk , Armstrong CL
Published: August 2012

The advantages of the embryonic chick as a model for studying neural development range from the relatively low cost of fertilized eggs to the rapid rate of development. We investigatedin ovocerebellar development in the chick, which has a nearly identical embryonic period as the mouse (19–22 days). We focused on three antigens: Calbindin (CB), Zebrin II (ZII), and Calretinin (CR), and our results demonstrate asynchronous expression patterns during cerebellar development. Presumptive CB+ Purkinje cells are first observed at embryonic day (E)10 in clusters in posterior cerebellum. At E12, corresponding with global expression of CB across the cerebellum, Purkinje cells began to express ZII. By E14–E16, Purkinje cells disperse into a monolayer and develop a pattern of alternating immunopositive and immunonegative ZII stripes. CR is initially expressed by clusters of presumptive Purkinje cells in the nodular zone at E8. However, this expression is transient and at later stages, CR is largely confined to the granule and molecular layers. Before hatch (E18–E20), Purkinje cells adopt a morphologically mature phenotype with complex dendritic arborizations. Comparing this data to that seen in mice, we found that the sequence of Purkinje cell formation, protein expression, and development is similar in both species, but these events consistently begin ∼5–7 days earlier in the precocial chick cerebellum, suggesting an important role for heterochrony in neurodevelopment. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Ölpflanzen in Europa
Authors: Bickel Susanne
Published: August 2012

Nachwachsende Rohstoffe erhalten zunehmende Bedeutung in Industrie und Technik. Ölpflanzen liefern Pflanzenöle, die für unsere Ernährung wichtig sind und gleichzeitig als Industrierohstoff eingesetzt werden können. Sie werden mittlerweile nicht nur als Treibstoff verwendet, sondern auch zur Herstellung von Schmierstoffen, Hydraulikölen, Waschmitteln, Farben und Lacken und zahlreichen weiteren Produkten. In Europa ist Raps die vorherrschende Ölpflanze, gefolgt von der Sonnenblume und der Olive. Rapsöl wird für die Säuglingsernährung empfohlen, weil es eine hohe Konzentration an α‐Linolensäure enthält, die einen wichtigen Baustein für die Gehirnentwicklung liefert.
Coregonen: Umkehrung der Artbildung
Authors: Kronberg Inge
Published: August 2012

Arten entstehen und vergehen – dieser Wandel der Diversität lässt sich nicht nur in erdgeschichtlichen Maßstäben beobachten. Diversitätsverluste durch den Einfluss des Menschen zeigen sich bereits innerhalb weniger Jahrzehnte. Arten verschwinden nicht nur, weil ihre Dichte schrittweise zurückgeht, sondern auch, weil sie sich mit nahe verwandten Arten vermischen. Das gilt besonders, wenn ein Lebensraum beispielsweise durch Eutrophierung so eintönig wird, dass Möglichkeiten zur spezifischen Einnischung schließlich fehlen.
Die Herstellung von Agarplatten für mikrobiologische Versuche
Authors: Schrödel Andrea
Published: August 2012

Bakterienkulturen können auf verschiedene Art und Weise gezüchtet werden. Setzt man dem flüssigen Nährmedium ein Geliermittel zu und gießt dieses noch heiß in Petrischalen, so erhält man nach dem Abkühlen Platten mit festem Nährboden von gelatineähnlicher Konsistenz. Auf diesen können Bakteriensuspensionen ausplattiert und bebrütet werden, bis einzelne Kolonien zu sehen sind.
Bernhard Rensch – biologischer Universalist im 20. Jahrhundert
Authors: Hoßfeld Uwe , Levit Georgy S. , Simunek Michal
Published: August 2012

Bernhard Rensch war ein ausgesprochen vielseitiger Biologe. Er gilt nicht nur im deutschen Sprachraum als einer der bedeutendsten (Evolutions‐)Biologen des 20. Jahrhunderts. Seine wissenschaftlichen Interessengebiete umfassten die Art‐ und Rassenbildung, Zoogeografie, Tierökologie, Tierpsychologie und die Synthetische Theorie der Evolution bis hin zur Biophilosophie und Kunst.
The impact of antioxidant supplements and endurance exercise on genes of the carbohydrate and lipid metabolism in skeletal muscle of mice
Authors: Meier Patrick , Renga Marcello , Hoppeler Hans , Baum Oliver
Published: August 2012

To ascertain whether reactive oxygen species (ROS) contribute to training‐induced adaptation of skeletal muscle, we administered ROS‐scavenging antioxidants (AOX; 140 mg/l of ascorbic acid, 12 mg/l of coenzyme Q10 and 1% N‐acetyl‐cysteine) via drinking water to 16 C57BL/6 mice. Sixteen other mice received unadulterated tap water (CON). One cohort of both groups (CONEXE and AOXEXE) was subjected to treadmill exercise for 4 weeks (16–26 m/min, incline of 5°–10°). The other two cohorts (CONSED and AOXSED) remained sedentary. In skeletal muscles of the AOXEXE mice, GSSG and the expression levels of SOD‐1 and PRDX‐6 were significantly lower than those in the CONEXE mice after training, suggesting disturbance of ROS levels. The peak power related to the body weight and citrate synthase activity was not significantly influenced in mice receiving AOX. Supplementation with AOX significantly altered the mRNA levels of the exercise‐sensitive genes HK‐II, GLUT‐4 and SREBF‐1c and the regulator gene PGC‐1alpha but not G6PDH, glycogenin, FABP‐3, MCAD and CD36 in skeletal muscle. Although the administration of AOX during endurance exercise alters the expression of particular genes of the ROS metabolism, it does not influence peak power or generally shift the metabolism, but it modulates the expression of specific genes of the carbohydrate and lipid metabolism and PGC‐1alpha within murine skeletal muscle. Copyright © 2012 John Wiley & Sons, Ltd.
Lys53 of Ribosomal Protein L36AL and the CCA End of a tRNA at the P/E Hybrid Site Are in Close Proximity on the Human Ribosome
Authors: Hountondji Codjo , Bulygin Konstantin , Woisard Anne , Tuffery Pierre , Créchet Jean‐Bernard , Pech Markus , Nierhaus Knud H. , Karpova Galina , Baouz Soria
Published: August 2012

Previously we have shown that the CCA end of a P‐tRNA can be crosslinked with the RPL36AL protein of the large subunit of mammalian ribosomes; it belongs to the L44e protein family present in all eukaryotic and archaeal ribosomes. Here we confirm and extend this finding and demonstrate that: 1) this crosslink is specific for a tRNA at the P/E hybrid site, as a tRNA in all other tRNA positions of pre‐translocational ribosomes could not be crosslinked with a ribosomal protein, 2) the crosslink was formed most efficiently with C74 and C75 of P/E‐tRNA, but could also connect the ultimate A of this tRNA with Lys53 of protein RPL36AL, 3) this protein contains seven monomethylated residues (three lysyl and three arginyl residues, as well as glutaminyl residue 51), 4) Q51 is part of a conserved GGQ motif in the L44e proteins in eukaryotic 80S ribosomes that is identical to the universally conserved motif of release factors implicated in promoting peptidyl‐tRNA hydrolysis, and 5) the large number of modifications, in which some of the residues were methylated to about 50 %, might indicate that protein RPL36AL is a preferential target for regulation.
A Raman Spectroscopic Study of the Speciation of Vanadia Supported on Ceria Nanocrystals with Defined Surface Planes
Authors: Wu Zili , Li Meijun , Overbury Steven H.
Published: August 2012

Vanadia (VOx) supported on ceria (CeO2) nanocrystals with defined surface planes, which includes rods, cubes and octahedra, was synthesized and used to explore the effect of support surface structure on the speciation of surface vanadia. The vanadia structures on these ceria “nanoshapes” were identified by in situ visible and UV Raman spectroscopy as a function of loading and calcination temperature, and they include monomeric, dimeric, trimeric, polymeric vanadia, and eventually crystalline V2O5 and CeVO4 as vanadia loading increases. As expected, the faceted ceria nanocrystals provide a rather homogeneous platform for anchoring the vanadia. At low vanadia surface density, only monomeric vanadia exists on the ceria nanoshapes, in contrast to vanadia supported on polycrystalline CeO2 in which multiple vanadia species coexist. Formation of CeVO4 from the reaction between surface vanadia and ceria upon high temperature calcination was compared for the three ceria nanoshapes with similar surface vanadia density (≈1/4 monolayer). It was found that both the surface structure and the amount of defect sites on the ceria nanoshapes play major roles in the production of CeVO4. The easier formation of CeVO4 on ceria rods, compared with cubes or octahedra, is attributed to the rods’ lowest surface oxygen vacancy formation energy and largest amount of defect sites.
Aromaticity‐Controlled Thermal Stability of Photochromic Systems Based on a Six‐Membered Ring as Ethene Bridges: Photochemical and Kinetic Studies
Authors: Yang Yuheng , Xie Yongshu , Zhang Qiong , Nakatani Keitaro , Tian He , Zhu Weihong
Published: August 2012

Three photochromic compounds—2‐butyl‐5,6‐bis[5‐(4‐methoxyphenyl)‐2‐methylthiophen‐3‐yl]‐1 H‐benzo[de]isoquinoline‐1,3(2 H)‐dione (BTE‐NA), 4,5‐bis[5‐(4‐methoxyphenyl)‐2‐methylthiophen‐3‐yl]benzo[c][1,2,5]thiadiazole (BTA), and BTTA, which contain naphthalimide, benzothiadiazole, and benzobisthiadiazole as six‐membered ethene bridges with different aromaticities—were systematically studied in solution, sol–gel, and single‐crystal states. They exhibit typical photochromic performance with considerably high cyclization quantum yields. BTE‐NA, BTA, and BTTA form a typical donor–π–acceptor (D–π–A) system with significant intramolecular charge transfer (ICT) between HOMO and LUMO upon excitation, thus realizing the fluorescence modulation by both photochromism and solvatochromism. The three ethene bridges with different degrees of aromaticity can provide a systematic comparison of the thermal stability evolution for their corresponding closed forms (c‐BTE‐NA, c‐BTA, and c‐BTTA). c‐BTE‐NA shows first‐order decay in various solvents from cyclohexane to acetonitrile. c‐BTA only shows first‐order decay in polar solvents such as chloroform, whereas it is stable in nonpolar solvents like toluene. In contrast, the less aromatic property of BTTA gives rise to its unprecedented thermal stability in various solvents even at elevated temperatures in toluene (328 K). Moreover, the small energy barrier between the parallel and antiparallel conformers allows the full conversion from BTTA to c‐BTTA. In well‐ordered crystal states, all three compounds adopt a parallel conformation. Interestingly, BTTA forms a twin crystal of asymmetric nature with interactions between the electron‐rich oxygen atom of the methoxy group and the carbon atom of the electron‐deficient benzobisthiadiazole moiety. This work contributes to the understanding of aromaticity‐controlled thermal stability of photochromic systems based on a six‐membered ring as an ethene bridge, and a broadening of the novel building blocks for photochromic bisthienylethene systems.
New Multifunctional Porous Materials Based on Inorganic–Organic Hybrid Single‐Walled Carbon Nanotubes: Gas Storage and High‐Sensitive Detection of Pesticides
Authors: Wang Feng , Zhao Jinbo , Gong Jingming , Wen Lili , Zhou Li , Li Dongfeng
Published: August 2012

Single‐walled carbon nanotubes (SWNTs) that are covalently functionalized with benzoic acid (SWNT‐PhCOOH) can be integrated with transition‐metal ions to form 3D porous inorganic–organic hybrid frameworks (SWNT‐Zn). In particular, N2‐adsorption analysis shows that the BET surface area increases notably from 645.3 to 1209.9 m2 g−1 for SWNTs and SWNT‐Zn, respectively. This remarkable enhancement in the surface area of SWNT‐Zn is presumably due to the microporous motifs from benzoates coordinated to intercalated zinc ions between the functionalized SWNTs; this assignment was also corroborated by NLDFT pore‐size distributions. In addition, the excess‐H2‐uptake maximum of SWNT‐Zn reaches about 3.1 wt. % (12 bar, 77 K), which is almost three times that of the original SWNTs (1.2 wt. % at 12 bar, 77 K). Owing to its inherent conductivity and pore structure, as well as good dispersibility, SWNT‐Zn is an effective candidate as a sensitive electrochemical stripping voltammetric sensor for organophosphate pesticides (OPs): By using solid‐phase extraction (SPE) with SWNT‐Zn‐modified glassy carbon electrode, the detection limit of methyl parathion (MP) is 2.3 ng mL−1.
Local Coordination Geometry and Spin State in Novel FeII Complexes with 2,6‐Bis(pyrazol‐3‐yl)pyridine‐Type Ligands as Controlled by Packing Forces: Structural Correlations
Authors: Craig Gavin A. , Costa José Sánchez , Roubeau Olivier , Teat Simon J. , Aromí Guillem
Published: August 2012

A substituted 2,6‐bis(pyrazol‐3‐yl)pyridine (3‐bpp) ligand, H4L, created to facilitate intermolecular interactions in the solid, has been used to obtain four novel FeII complexes: [Fe(H4L)2](ClO4)2⋅2 CH3NO2⋅2 H2O, [Fe(H4L)(H2LBF2)](BF4)⋅5 C3H6O (H2LBF2 is an in situ modified version of H4L), [Fe(H4L)2](ClO4)2⋅2 C3H7OH and [Fe(H4L)2](ClO4)2⋅4 C2H5OH. Changing of spin‐inactive components (solvents, anions or distant ligand substituents) causes differences to the coordination geometry of the metal that are key to the magnetic proper‐ ties. Magnetic measurements show that, contrary to the previously published complex [Fe(H4L)2](ClO4)2⋅H2O⋅2 CH3COCH3, the newly synthesised compounds remain in the high‐spin (HS) state at all temperatures (5–300 K). A member of the known family of FeII/3‐bpp complexes, [Fe(3‐bpp)2](ClO4)2⋅1.75 CH3COCH3⋅1.5 Et2O, has also been prepared and characterised structurally. In the bulk, this compound exhibits a gradual and incomplete spin transition near 205 K. The single‐crystal structure is consistent with it being HS at 250 K and partially low spin at 90 K. Structural analysis of all these compounds reveals that the exact configuration of intermolecular interactions affects dramatically the local geometry at the metal, which ultimately has a strong influence on the magnetic properties. Along this line, the geometry of FeII in all published 3‐bpp compounds of known structure has been examined, both by calculating various distortion indices (Σ, Θ, θ and Φ) and by continuous shape measures (CShMs). The results reveal correlations between some of these parameters and indicate that the distortions from octahedral geometry observed on HS systems are mainly due to strains arising from intermolecular interactions. As previously suggested with other related compounds, we observe here that strongly HS‐distorted systems have a larger tendency to remain in that state.
Hydrogen Bonding Directed Supramolecular Polymerisation of Oligo(Phenylene‐Ethynylene)s: Cooperative Mechanism, Core Symmetry Effect and Chiral Amplification
Authors: Wang Feng , Gillissen Martijn A. J. , Stals Patrick J. M. , Palmans Anja R. A. , Meijer E. W.
Published: August 2012

The design of supramolecular motifs with tuneable stability and adjustable supramolecular polymerisation mechanisms is of crucial importance to precisely control the properties of supramolecular assemblies. This report focuses on constructing π‐conjugated oligo(phenylene ethynylene) (OPE)‐based one‐dimensional helical supramolecular polymers that show a cooperative growth mechanism. Thus, a novel set of discotic molecules comprising a rigid OPE core, three amide groups, and peripheral solubilising wedge groups featuring C3 and C2 core symmetry was designed and synthesised. All of the discotic molecules are crystalline compounds and lack a columnar mesophase in the solid state. In dilute methylcyclohexane solution, one‐dimensional supramolecular polymers are formed stabilised by threefold intermolecular hydrogen bonding and π–π interactions, as evidenced by 1H NMR measurements. Small‐angle X‐ray and light scattering measurements reveal significant size differences between the columnar aggregates of C3‐ and C2‐symmetrical discotics, that is, the core symmetry strongly influences the nature of the supramolecular polymerisation process. Temperature‐dependent CD measurements show a highly cooperative polymerisation process for the C3‐symmetrical discotics. In contrast, the self‐assembly of C2‐symmetrical discotics shows a smaller enthalpy release upon aggregation and decreased cooperativity. In all cases, the peripheral stereogenic centres induce a preferred handedness in the columnar helical aggregates. Moreover, one stereogenic centre suffices to fully bias the helicity in the C2‐symmetrical discotics. Finally, chiral amplification studies with the C3‐symmetrical discotics were performed by mixing chiral and achiral discotics (sergeants‐and‐soldiers experiment) and discotics of opposite chirality (majority‐rules experiment). The results demonstrate a very strong sergeants‐and‐soldiers effect and a rather weak majority‐rules effect.