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The future of medium - Extended-range weather prediction - User perspectives

BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY 2007年第5期88卷 634-638页

作者： Keller, Linda M. Houghton, David D. Morgan, Michael C. Univ Wisconsin Madison WI 53706 USA

The article presents an opinion on the future of medium-range and extended-range numerical weather forecasting and geophysical prediction. Challenges include the lack of an understanding of the limits of predictability and the dynamics of particular phenomena and increased forecast consumer sophistication. Subseasonal prediction problems will be characterized as statistical or probabilistic.

关键词： weather forecasting fronts User needs guidance commodities surface circulation

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MR-compatible assistance system for punction in a high-field system: device and feasibility of transgluteal biopsies of the prostate gland

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EUROPEAN RADIOLOGY 2007年第4期17卷 1118-1124页

作者： Zangos, Stephan Herzog, Christopher Eichler, Katrin Hammerstingl, Renate Lukoschek, Andreas Guthmann, Stefanie Gutmann, Bernd Schoepf, Uwe Joseph Costello, Phillip Vogl, Thomas J. Goethe Univ Frankfurt Univ Hosp Frankfurt Inst Diagnost & Intervent Radiol D-60590 Frankfurt Germany Innomed GmbH D-76863 Herxheim Germany Med Univ S Carolina Dept Radiol Charleston SC 29425 USA

We present the first cadavic study results concerning the feasibility of the use of an MR-guided assistance system, Innomotion (Innomedic, Herxheim, Germany), for accurate and consistent placement of percutaneous needles in the prostate gland. The MR-compatible assistance system consists of a C-arch, guiding arm and application module (AMO). T1-weighted fast low angle shot (FLASH) 2-D-GRE sequence (TR/TE=110/4 ms) and T2-weighted turbo spin-echo (TSE)-sequences (TR/TE=3200/97 ms) in transversal orientation were used for the monitoring of the punction of the prostate gland. Planning and control of the intervention is to be made outside the scanner room on a desktop computer that receives DICOM images from the scanner. Servopneumatic drives move the AMO to the insertion point. The physician has to introduce the punction needle manually. The mean deviation of the needle tip to the target in a gel phantom was 0.35 mm. An accurate punction of the prostate gland can easily be performed using this system with a transgluteal access. The T2-weighted images are superior for the evaluation of the prostate anatomy and the needle position during the interventions. In conclusion, our preliminary results indicate that this MR-guided assistance system is suitable for an accurate transgluteal needle placement in the prostate.

关键词： magnetic resonance (MR) prostate neoplasms guidance

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Multilevel surface nano- and microstructuring via sequential photoswelling of dichromated gelatin

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LANGMUIR 2007年第10期23卷 5419-5422页

作者： Paszewski, Maciej Smoukov, Stoyan K. Klajn, Rafal Grzybowski, Bartosz A. Northwestern Univ Dept Chem Evanston IL 60208 USA Northwestern Univ Dept Chem & Biol Engn Evanston IL 60208 USA

Photoswelling of thin films of dichromated gelatin provides a basis for fabrication of multilevel surface reliefs via sequential UV illumination through different photomasks. The remarkable feature of this simple, benchtop technique is that by adjusting irradiation times, film thickness, or its hydration state the heights of the developed features can be varied from few nanometers to tens of microns. After UV exposure, the surface structures can be replicated faithfully into either soft or hard PDMS stamps.

关键词： LITHOGRAPHY FABRICATION FILMS WATER THIN CRYSTALS guidance COLLAGEN

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Usefulness of live 3D echocardiography during radiofrequency ablation in a case of hepatocellular carcinoma

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CLINICAL IMAGING 2007年第4期31卷 283-286页

作者： Hotta, Naoki Ayada, Minoru Okumura, Akihiko Ishikawa, Tetsuya Kakumu, Shinichi Aichi Med Univ Sch Med Div Gastroenterol Dept Internal Med Aichi 48001195 Japan

We report a case of hepatocellular carcinoma (HCC) with chronic hepatitis C virus (HCV) infection, which was successfully treated with percutaneous radiofrequency ablation (RFA) under live three-dimensional (3D) echocardiography guidance. Recently, it was reported that live 3D echocardiography was able to enhance the efficacy of catheter-based endomyocardial injection since the 3D images made it possible to observe the target from multiple directions so that it guided more accurately. A 63-year-old Japanese man had an HCC nodule of 3.0 cm in diameter at the S8 region of the liver. Here we applied live 3D echocardiography during RFA therapy with a LeVeen needle electrode. The echocardiography guidance allowed for easier and accurate approach for needle puncture. The guidance was also effective to confirm whether an enough safety margin for the nodule was obtained. Thus, live 3D echocardiography appears to safely guide REA needles by accurate targeting for HCC nodule, providing real-time visualization when combined with echocardiography contrast. (C) 2007 Elsevier Inc. All rights reserved.

关键词： Echocardiography radiofrequency ablation Nodulus cerebelli Primary carcinoma of the liver cells 超声心动描记术 Three-Dimensional Images SAFETY MARGINS Hepatocellular Cancer RCRA FACILITY ASSESSMENT radiofrequency ablation three dimensional echocardiography Echocardiography guidance

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Introduction to modes and their designation in circular and elliptical fibers

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AMERICAN JOURNAL OF PHYSICS 2007年第6期75卷 546-551页

作者： Kumar, Deepak Choudhury, P. K. Multimedia Univ Fac Engn Cyberjaya 63100 Malaysia

Some basic ideas are presented to clarify the concept of modes in optical fibers. We describe the formation of modes and the indexing schemes in circular and elliptical core fibers. (C) 2007 American Association of Ph... 详细信息

关键词： CORE-CLADDING BOUNDARY INDEX OPTICAL FIBERS WAVE-GUIDE ELECTROMAGNETIC-WAVES HYBRID MODES 2-MODE FIBER PROPAGATION WAVEGUIDES guidance CUTOFF

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The shape of the olfactory bulb influences axon targeting

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BRAIN RESEARCH 2007年第1期1169卷 17-23页

作者： Chehrehasa, Fatemeh Key, Brian St John, James A. Univ Queensland Sch Biomed Sci Discipline Anat & Dev Biol Brain growth Regenerat Lab Brisbane Qld 4072 Australia Univ Queensland Ctr Funct & Appl Genom Brisbane Qld 4072 Australia Zahedan Univ Med Sci Iran Zahedan Iran

Each primary olfactory neuron in the mouse expresses a single type of odorant receptor. All neurons expressing the same odorant receptor gene typically project to two topographically fixed glomeruli, one each on the medial and lateral surfaces of the olfactory bulb. While topographic gradients of guidance receptors and their ligands help to establish the retinotectal projection, similar orthogonal distributions of cues have not yet been detected within the olfactory system. While odorant receptors are crucial for the final targeting of axons to glomeruli, it is unclear whether the olfactory bulb itself provides instructive cues for the establishment of the topographic map. To begin to understand the role of the olfactory bulb in the formation of the olfactory nerve pathway, we developed a model whereby the gross shape of the bulb in the P2-IRES-tau-LacZ line of mice was radically altered during postnatal development. We have shown here that the topography of axons expressing the P2 odorant receptor is dependent on the shape of the olfactory bulb. When the dorsoventral axis of the olfactory bulb was compressed during the early postnatal period, newly developing P2 axons projected to multiple inappropriate glomeruli surrounding their normal target site. These results suggest that the distribution of local guidance cues within the olfactory bulb is influenced by the shape of the olfactory bulb and that these cues contribute to the topographic positioning of glomeruli. Crown Copyright (C) 2007 Published by Elsevier B.V. All rights reserved.

关键词： bulbectomy development glomerulus guidance neuron topography

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Comparison of contaminated site human health risk assessment approaches in Canada: Application of provincial methods to a hypothetical site

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HUMAN AND ECOLOGICAL RISK ASSESSMENT 2007年第6期13卷 1228-1254页

作者： Loney, C. B. Richardson, G. M. Leece, B. D. Wilson, R. M. Klee, U. MacLean, B. J. Dillon Consulting Ltd Ottawa ON K1J 9N5 Canada Hlth Canada Contaminated Sites Div Ottawa ON Canada Wilson Sci Consulting Inc Vancouver BC Canada Dillon Consulting Ltd Cambridge NS Canada Dillon Consulting Ltd Cambridge ON Canada

Human health risk assessment, whether at the screening level or more complex phase, is not an exact science. A wide variety of advice and direction is offered by international, national, and provincial/state environmental agencies regarding the conduct of risk assessment, and different risk assessors access and rely on the available regulatory advice and direction differently. This may result in wide variability in the estimates of chemical exposure and risk. A comparison of human health risk assessment approaches practiced at the provincial level in Canada was undertaken, wherein each jurisdiction's approach was applied to a hypothetical contaminated site. Approaches were found to vary both in terms of methodological considerations, and in matters of policy. The exercise yielded results in terms of estimated exposures and predicted hazard quotients/indexes and incremental lifetime cancer risks that were in some cases quite consistent (varying by a factor of less than 1.5 times), and in other cases remarkably different (varying by orders of magnitude). This article reviews the various approaches/frameworks applied and discusses the results of the hypothetical risk assessments, in terms of both the observed variation and the source of this variability.

关键词： human health risk assessment guidance variability

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Combined activation of calpain and calcineurin during ligand-induced growth cone collapse

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MOLECULAR AND CELLULAR NEUROSCIENCE 2007年第4期36卷 425-434页

作者： To, Kenneth C. W. Church, John O'Connor, Timothy P. Univ British Columbia Dept Cellular & Physiol Sci Vancouver BC V6T 1Z3 Canada Univ British Columbia Grad Program Neurosci Vancouver BC V6T 1Z3 Canada

Calcium plays a key role during growth cone collapse. Recently, it has been proposed that low- and high-amplitude rises in [Ca2+](i) result in the activation of the neurite outgrowth inhibiting proteins calcineurin and calpain, respectively. However, it remains unknown if and how these mechanisms are modulated by specific guidance cues. Here we report that the inhibitory cue Semaphorin 5B induces growth cone collapse by promoting the influx of extracellular Ca2+. The resulting rise in [Ca2+](i) is characterized by a low-amplitude increase followed by a marked secondary rise, suggesting the potential involvement of both calcineurin and calpain. In support of this, inhibition of either effector attenuated Sema5B-induced collapse, a result that was augmented by the simultaneous inhibition of both targets. Furthermore, we provide evidence that Sema5B induces calpain-mediated cleavage of calcineurin. We thus show for the first time that ligand-induced growth cone collapse can activate both calcineurin- and calpain-mediated pathways concurrently. (c) 2007 Elsevier Inc. All rights reserved.

关键词： MYELIN-ASSOCIATED GLYCOPROTEIN DORSAL-ROOT GANGLION NEURITE OUTGROWTH NERVE GROWTH GAP-43 NEUROMODULIN CALCIUM TRANSIENTS F-ACTIN guidance NEURONS CHANNELS Neuronal Outgrowth Calcineurin F-Actin nerve growth myelin associated glycoprotein Collapse Growth Cones guidance Neurons Calpain

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Accuracy of CT-guided transthoracic needle biopsy of lung lesions: factors affecting diagnostic yield

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RADIOLOGIA MEDICA 2007年第8期112卷 1142-1159页

作者： Priola, A. M. Priola, S. M. Cataldi, A. Errico, L. Di Franco, M. Campisi, P. Molinaro, L. Marci, V. Novello, S. Fava, C. Univ Turin ASO San Luigi Gonzaga I-10043 Orbassano TO Italy Univ Turin ASO San Giovanni Battista Turin Italy

Purpose. This study was performed to analyse the variables affecting the diagnostic accuracy of computed tomography (CT)-guided transthoracic needle biopsy of pulmonary lesions. Materials and methods. A retrospective study of 612 consecutive procedures with confirmed final diagnoses was undertaken. Benign and malignant needle biopsy results were compared with final outcomes to determine diagnostic accuracy. A statistical analysis of factors related to patient characteristics, lung lesions and biopsy technique was performed to determine possible influences on diagnostic yield. A p value less than 0.05 was interpreted as statistically significant. Results. There were 508 (83%) malignant and 104 (17%) benign lesions. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy for a diagnosis of malignancy were 90.2%. 99.0%. 99.8%. 67.3% and 91.7%, respectively. Overall diagnostic accuracy was 83.3%. Variables affecting diagnostic accuracy were the final diagnosis (benign 67%, malignant 92%;p<0.001) and lesion size (lesions<1.5 cm 68%, lesions 1.5-5.0 cm 87%. lesions>5 cm 78%;p<0.05). Conclusions. In CT-guided transthoracic needle biopsy, the final diagnosis and lesion size affect diagnostic accuracy: benign lung lesions and lesions smaller than 1.5 cm or larger than 5.0 cm in diameter provide lower diagnostic yield.

关键词： lung biopsy computed tomography (CT) guidance accuracy

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Filopodial actin bundles are not necessary for microtubule advance into the peripheral domain of Aplysia neuronal growth cones

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NATURE CELL BIOLOGY 2007年第12期9卷 1360-U39页

作者： Burnette, Dylan T. Schaefer, Andrew W. Ji, Lin Danuser, Gaudenz Forscher, Paul Yale Univ Dept Mol Cellular & Dev Biol New Haven CT 06511 USA Scripps Res Inst Dept Cell Biol La Jolla CA 92037 USA

Filopodial actin bundles guide microtubule assembly in the growth cone peripheral ( P) domain and retrograde actin-network flow simultaneously transports microtubules rearward. Therefore, microtubule-end position is determined by the sum of microtubule assembly and retrograde transport rates. However, how filopodia actually affect microtubule assembly dynamics is unknown. To address this issue we quantitatively assessed microtubule and actin dynamics before and after selective removal of filopodia. Filopodium removal had surprisingly little effect on retrograde actin-flow rates or underlying network structures, but resulted in an approximate doubling of peripheral microtubule density and deeper penetration of microtubules into the P domain. The latter stemmed from less efficient coupling of microtubules to remaining actin networks and not from a change in microtubule polymer dynamics. Loss of filopodia also resulted in increased lateral microtubule movements and a more randomized microtubule distribution in the P domain. In summary, filopodia do not seem to be formally required for microtubule advance;however, their presence ensures radial distribution of microtubules in the P domain and facilitates microtubule transport by retrograde flow. The resulting dynamic steady state has interesting implications for rapid microtubule-positioning responses in the P domain.

关键词： FLUORESCENT SPECKLE MICROSCOPY DYNAMIC INSTABILITY ENA/VASP PROTEINS MIGRATING CELLS CYTOCHALASIN-B 2 POPULATIONS FILAMENTS guidance FLOW ORGANIZATION

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