bluuebunny/crossref_metadata_2025_split huggingface dataset:
Controlled Synthesis of Monodisperse Sub‐100 nm Hollow SnO2 Nanospheres: A Template‐ and Surfactant‐Free Solution‐Phase Route, the Growth Mechanism, Optical Properties, and Application as a Photocatalyst
Authors: Wu Wei , Zhang Shaofeng , Zhou Juan , Xiao Xiangheng , Ren Fen , Jiang Changzhong 
Published: July 2011

AbstractControlled synthesis of low‐dimensional materials, such as nanoparticles, nanorods, and hollow nanospheres, is vitally important for achieving desired properties and fabricating functional devices. We report a systematic investigation of the growth of low‐dimensional sub‐100 nm SnO2 hollow nanostructures by a mild template‐ and surfactant‐free hydrothermal route, aiming to achieve precise control of morphology and size. The starting materials are potassium stannate and urea in an ethylene glycol (EG)/H2O system. We found the size of the SnO2 hollow nanospheres can be controlled by simply adjusting the urea concentration. Investigation of the mechanism of formation of the SnO2 hollow nanospheres revealed that reaction time, urea concentration, and reaction temperature make significant contributions to the growth of hollow nanospheres. On switching the solvent from EG/H2O to H2O or ethanol, the SnO2 nanostructures changed from nanospheres to ultrafine nanorods and nanoparticles. On the basis of reaction parameter dependent experiments, oriented self‐assembly and subsequent evacuation through Ostwald ripening are proposed to explain the formation of hollow nanostructures. Their size‐dependent optical properties, including UV/Vis absorption spectra and room‐temperature fluorescence spectra, were also studied. Moreover, the studies on the photocatalytic property demonstrate that the fabricated hollow structures have slightly enhanced photocatalytic degradation activity for rhodamine B when exposed to mercury light irradiation compared to solid SnO2 nanospheres under the same conditions. The synthesized tin oxide nanoparticles display high photocatalytic efficiency and have potential applications for cleaning polluted water in the textile industry.
One‐Pot Functionalization of Graphene with Porphyrin through Cycloaddition Reactions
Authors: Zhang Xiaoyan , Hou Lili , Cnossen Arjen , Coleman Anthony C. , Ivashenko Oleksii , Rudolf Petra , van Wees Bart J. , Browne Wesley R. , Feringa Ben L. 
Published: July 2011

AbstractTwo types of graphene‐based hybrid materials, graphene‐TPP (TPP=tetraphenylporphyrin) and graphene‐PdTPP (PdTPP=palladium tetraphenylporphyrin), were prepared directly from pristine graphene through one‐pot cycloaddition reactions. The hybrid materials were characterized by thermogravimetric analysis (TGA), by TEM, by UV/Vis, FTIR, Raman, and luminescence spectroscopy, and by fluorescence/phosphorescence lifetime measurements. The presence of the covalent linkages between graphene and porphyrin was confirmed by FTIR and Raman spectroscopy and further supported by control experiments. The presence of TPP (or PdTPP) in the hybrid material was demonstrated by UV/Vis spectroscopy, with TGA results indicating that the graphene‐TPP and graphene‐PdTPP hybrid materials contained approximately 18 % TPP and 20 % PdTPP. The quenching of fluorescence (or phosphorescence) and reduced lifetimes suggest excited state energy/electron transfer between graphene and the covalently attached TPP (or PdTPP) molecules.
Post‐therapy pathologic stage and survival in patients with pancreatic ductal adenocarcinoma treated with neoadjuvant chemoradiation
Authors: Estrella Jeannelyn S. , Rashid Asif , Fleming Jason B. , Katz Matthew H. , Lee Jeffrey E. , Wolf Robert A. , Varadhachary Gauri R. , Pisters Peter W. T. , Abdalla Eddie K. , Vauthey Jean‐Nicolas , Wang Hua , Gomez Henry F. , Evans Douglas B. , Abbruzzese James L. , Wang Huamin 
Published: July 2011

AbstractBACKGROUND:Neoadjuvant chemoradiation before surgery is an emerging treatment modality for pancreatic ductal adenocarcinoma (PDAC). However, analysis of prognostic factors is limited for patients with PDAC treated with neoadjuvant chemoradiation and pancreaticoduodenectomy (PD).METHODS:The study population was comprised of 240 consecutive patients with PDAC who received neoadjuvant chemoradiation and PD and was compared with 60 patients who had no neoadjuvant therapy between 1999 and 2007. Clinicopathologic features were correlated with disease‐free survival (DFS) and overall survival (OS).RESULTS:Among the 240 treated patients, the 1‐year and 3‐year DFS rates were 52% and 32%, with a median DFS of 15.1 months. The 1‐year and 3‐year OS rates were 95% and 47%, with a median OS of 33.5 months. By univariate analysis, DFS was associated with age, post‐therapy tumor stage (ypT), lymph node status (ypN), number of positive lymph nodes, and American Joint Committee on Cancer (AJCC) stage, whereas OS was associated with intraoperative blood loss, margin status, ypT, ypN, number of positive lymph nodes, and AJCC stage. By multivariate analysis, DFS was independently associated with age, number of positive lymph nodes, and AJCC stage, and OS was independently associated with differentiation, margin status, number of positive lymph nodes, and AJCC stage. In addition, the treated patients had better OS and lower frequency of lymph node metastasis than those who had no neoadjuvant therapy.CONCLUSIONS:In patients with PDAC who received neoadjuvant chemoradiation and subsequent PD, post‐therapy pathologic AJCC stage and number of positive lymph nodes are independent prognostic factors. Cancer 2012. © 2011 American Cancer Society.
Computational exploration of disinfection of bacterial biofilms in partially blocked channels
Authors: Cogan N. G. 
Published: July 2011

SUMMARYThe failure of typical disinfectant protocols to eliminate bacterial biofilms is one of the major concerns in industrial, clinical, and environmental biofilm control. Biofilms have a variety of mechanisms that protect the bacteria including physiological, physical, and phenotypic mechanisms. This investigation focuses on an aspect of protection that exploits the combination of physiological tolerance and nutrient gradients. In particular, the fluid flow in a channel that is partially blocked introduces diffusion limited zones where the bacteria can evade the disinfectant challenge. These zones are both up‐ and down‐stream of the obstacle.Using a computational study of a two‐fluid system, this novel mechanism is explored. The model is numerically solved using a hybrid boundary integral method where boundary conditions are implemented using the free space Green's function to determine forces that are imparted on the fluid by the boundaries. Copyright © 2011 John Wiley & Sons, Ltd.
GPGPUs in computational finance: massive parallel computing for American style options
Authors: Pagès Gilles , Wilbertz Benedikt 
Published: July 2011

SUMMARYThe pricing of American style and multiple exercise options is a very challenging problem in mathematical finance. One usually employs a least squares Monte Carlo approach (Longstaff–Schwartz method) for the evaluation of conditional expectations, which arise in the backward dynamic programming principle for such optimal stopping or stochastic control problems in a Markovian framework. Unfortunately, these least squares MC approaches are rather slow and allow, because of the dependency structure in the backward dynamic programming principle, no parallel implementation neither on the MC level nor on the time layer level of this problem. We therefore present in this paper a quantization method for the computation of the conditional expectations that allows a straightforward parallelization on the MC level. Moreover, we are able to develop for first‐order autoregressive processes a further parallelization in the time domain, which makes use of faster memory structures and therefore maximizes parallel execution. Furthermore, we discuss the generation of random numbers in parallel on a GPGPU architecture, which is the crucial tool for the application of massive parallel computing architectures in mathematical finance. Finally, we present numerical results for a CUDA implementation of these methods. It will turn out that such an implementation leads to an impressive speed‐up compared with a serial CPU implementation. Copyright © 2011 John Wiley & Sons, Ltd.
Moving huge scientific datasets over the Internet
Authors: Liu Wantao , Tieman Brian , Kettimuthu Rajkumar , Foster Ian 
Published: July 2011

SUMMARYModern scientific experiments can generate hundreds of gigabytes to terabytes or even petabytes of data that may be maintained in large numbers of relatively small files. Frequently, these data must be disseminated to remote collaborators or computational centers for data analysis. Moving this dataset with high performance and strong robustness and providing a simple interface for users are challenging tasks. We present a data transfer framework comprising a high‐performance data transfer library based on GridFTP, an extensible data scheduler with four data scheduling policies, and a GUI that allows users to transfer their dataset easily, reliably, and securely. This system incorporates automatic tuning mechanisms to select at runtime the number of concurrent threads to be used for transfers. Also included are restart mechanisms for handling client, network, and server failures. Experimental results indicate that our data transfer system can significantly improve data transfer performance and can recover well from failures. Copyright © 2011 John Wiley & Sons, Ltd.
Terahertz Time‐Domain Spectroscopy of Gases, Liquids, and Solids
Authors: Theuer Michael , Harsha Srikantaiah Sree , Molter Daniel , Torosyan Garik , Beigang René 
Published: July 2011

AbstractThe techniques and methods employed in the spectroscopic characterization of gases, liquids, and solids in the terahertz frequency range are reviewed. Terahertz time‐domain spectroscopy is applied to address a broadband frequency range between 100 GHz and 5 THz with a sub‐10 GHz frequency resolution. The unique spectral absorption features measured can be efficiently used in material identification and sensing. Possibilities and limitations of fundamental and industrial applications are discussed.
A DFT Investigation of Surface‐Enhanced Raman Scattering of Adenine and 2′‐Deoxyadenosine 5′‐Monophosphate on Ag20 Nanoclusters
Authors: Lang Xiu‐Feng , Yin Peng‐Gang , You Ting‐Ting , Jiang Li , Guo Lin 
Published: July 2011

AbstractWe present a detailed analysis of the surface‐enhanced Raman scattering (SERS) of adenine and 2′‐deoxyadenosine 5′‐monophosphate (dAMP) adsorbed on an Ag20 cluster by using density functional theory. Calculated Raman spectra show that spectral features of all complexes depend greatly on adsorption sites of adenine and dAMP. The complexes consisting of adenine adsorbed on the Ag20 cluster through N3 reproduce the measured SERS spectra in silver colloids, and thus demonstrated that adenine interacts with the silver surface via N3. We also investigate the SERS spectrum of adenine at the junction between two Ag20 clusters and demonstrate that adenine can bind to the clusters through N3 and the external amino group, while dAMP can be adsorbed on the cluster in an end‐on orientation with the ribose and phosphate groups near to or away from the silver cluster. In contrast to the adenine–Ag20 complexes, the dAMP–Ag20 complexes produce new and strong bands in the low‐ or high‐wavenumber region of the Raman spectra, due to vibrations of the ribose and phosphate groups. Furthermore, the spectrum of dAMP bound to the Ag20 cluster via N7 approaches the experimental SERS spectra on silver colloids.
Transport of Gases between the Environment and Alveoli—Theoretical Foundations
Authors: Butler James P. , Tsuda Akira 
Published: July 2011

AbstractThe transport of oxygen and carbon dioxide in the gas phase from the ambient environment to and from the alveolar gas/blood interface is accomplished through the tracheobronchial tree, and involves mechanisms of bulk or convective transport and diffusive net transport. The geometry of the airway tree and the fluid dynamics of these two transport processes combine in such a way that promotes a classical fractionation of ventilation into dead space and alveolar ventilation, respectively. This simple picture continues to capture much of the essence of gas phase transport. On the other hand, a more detailed look at the interaction of convection and diffusion leads to significant new issues, many of which remain open questions. These are associated with parallel and serial inhomogeneities especially within the distal acinar units, velocity profiles in distal airways and terminal spaces subject to moving boundary conditions, and the serial transport of respiratory gases within the complex acinar architecture. This article focuses specifically on the theoretical foundations of gas transport, addressing two broad areas. The first deals with the reasons why the classical picture of alveolar and dead space ventilation is so successful; the second examines the underlying assumptions within current approximations to convective and diffusive transport, and how they interact to effect net gas exchange. © 2011 American Physiological Society.Compr Physiol1:1301‐1316, 2011.
History of Respiratory Gas Exchange
Authors: West John B. 
Published: July 2011

AbstractAs early as the 6th century B.C. the Greeks speculated on a substancepneumathat meant breath or soul, and they argued that this was essential for life. An important figure in the 2nd century A.D. was Galen whose school developed an elaborate cardiopulmonary system that influenced scientific thinking for 1400 years. A key concept was that blood was mixed with pneuma from the lung in the left ventricle thus formingvital spirit. It was also believed that blood flowed from the right to the left ventricle of the heart through pores in the interventricular septum but this view was challenged first by the Arab physician Ibn al‐Nafis in the 13th century and later by Michael Servetus in the 16th century. The 17th century saw an enormous burgeoning of knowledge about the respiratory gases. First Torricelli explained the origin of atmospheric pressure, and then a group of physiologists in Oxford clarified the properties of inspired gas that were necessary for life. This culminated in the work of Lavoisier who first clearly elucidated the nature of the respiratory gases, oxygen, carbon dioxide and nitrogen. At that time it was thought that oxygen was consumed in the lung itself, and the fact that the actual metabolism took place in peripheral tissues proved to be a very elusive concept. It was not until the late 19th century that the issue was finally settled by Pflüger. In the early 20th century there was a colorful controversy about whether oxygen was secreted by the lung. During and shortly after World War II, momentous strides were made on the understanding of pulmonary gas exchange, particularly the role of ventilation‐perfusion inequality. A critical development in the 1960s was the introduction of blood gas electrodes, and these have transformed the management of patients with severe lung disease. © 2011 American Physiological Society.Compr Physiol1:1509‐1523, 2011.
Causes of and Compensations for Hypoxemia and Hypercapnia
Authors: West John B. 
Published: July 2011

AbstractBy far the commonest cause of impaired gas exchange in patients with lung disease is ventilation‐perfusion inequality. This is a complicated topic and much can be learned from computer models. Ventilation‐perfusion inequality always causes hypoxemia, that is, an abnormally low Po2in arterial blood. However, it is also the commonest cause of an increased arterial Pco2, or hypercapnia, in patients with chronic obstructive pulmonary disease (COPD). There is often confusion in this area with some people attributing the CO2retention to “hypoventilation” when in fact these patients are usually moving much more air into their lungs than normal subjects. A patient with COPD can often return the arterial Pco2to normal by increasing the ventilation. However, this does not return the arterial Po2to normal because of the different shapes of the oxygen and carbon dioxide dissociation curves. Increasing pulmonary blood flow in the presence of ventilation‐perfusion inequality usually raises the arterial Po2but much less than increasing ventilation. Raising the inspired oxygen concentration is typically very effective in increasing the arterial Po2. Ventilation‐perfusion inequality interferes with the transfer of all gases by the lung including the anesthetic gases. The gas exchange behavior of a lung depends greatly on the pattern of ventilation‐perfusion inequality. It is theoretically possible to find a distribution that improves the transfer of some gases but this requires bizarre conditions that can never occur in practice. © 2011 American Physiological Society.Compr Physiol1:1541‐1553, 2011.
Mechanics of the Respiratory Muscles
Authors: De Troyer André , Boriek Aladin M. 
Published: July 2011

AbstractThis article examines the mechanics of the muscles that drive expansion or contraction of the chest wall during breathing. The diaphragm is the main inspiratory muscle. When its muscle fibers are activated in isolation, they shorten, the dome of the diaphragm descends, pleural pressure (Ppl) falls, and abdominal pressure (Pab) rises. As a result, the ventral abdominal wall expands, but a large fraction of the rib cage contracts. Expansion of the rib cage during inspiration is produced by the external intercostals in the dorsal portion of the rostral interspaces, the intercartilaginous portion of the internal intercostals (the so‐called parasternal intercostals), and, in humans, the scalenes. By elevating the ribs and causing an additional fall inPpl, these muscles not only help the diaphragm expand the chest wall and the lung, but they also increase the load on the diaphragm and reduce the shortening of the diaphragmatic muscle fibers. The capacity of the diaphragm to generate pressure is therefore enhanced. In contrast, during expiratory efforts, activation of the abdominal muscles produces a rise inPabthat leads to a cranial displacement of the diaphragm into the pleural cavity and a rise inPpl. Concomitant activation of the internal interosseous intercostals in the caudal interspaces and the triangularis sterni during such efforts contracts the rib cage and helps the abdominal muscles deflate the lung. © 2011 American Physiological Society.Compr Physiol1:1273‐1300, 2011.
Endothelial and Smooth Muscle Cell Ion Channels in Pulmonary Vasoconstriction and Vascular Remodeling
Authors: Makino Ayako , Firth Amy L. , Yuan Jason X.‐J. 
Published: July 2011

AbstractThe pulmonary circulation is a low resistance and low pressure system. Sustained pulmonary vasoconstriction and excessive vascular remodeling often occur under pathophysiological conditions such as in patients with pulmonary hypertension. Pulmonary vasoconstriction is a consequence of smooth muscle contraction. Many factors released from the endothelium contribute to regulating pulmonary vascular tone, while the extracellular matrix in the adventitia is the major determinant of vascular wall compliance. Pulmonary vascular remodeling is characterized by adventitial and medial hypertrophy due to fibroblast and smooth muscle cell proliferation, neointimal proliferation, intimal, and plexiform lesions that obliterate the lumen, muscularization of precapillary arterioles, andin situthrombosis. A rise in cytosolic free Ca2+concentration ([Ca2+]cyt) in pulmonary artery smooth muscle cells (PASMC) is a major trigger for pulmonary vasoconstriction, while increased release of mitogenic factors, upregulation (or downregulation) of ion channels and transporters, and abnormalities in intracellular signaling cascades are key to the remodeling of the pulmonary vasculature. Changes in the expression, function, and regulation of ion channels in PASMC and pulmonary arterial endothelial cells play an important role in the regulation of vascular tone and development of vascular remodeling. This article will focus on describing the ion channels and transporters that are involved in the regulation of pulmonary vascular function and structure and illustrating the potential pathogenic role of ion channels and transporters in the development of pulmonary vascular disease. © 2011 American Physiological Society.Compr Physiol1:1555‐1602, 2011.
Dopamine and Renal Function and Blood Pressure Regulation
Authors: Armando Ines , Villar Van Anthony M. , Jose Pedro A. 
Published: July 2011

AbstractDopamine is an important regulator of systemic blood pressure via multiple mechanisms. It affects fluid and electrolyte balance by its actions on renal hemodynamics and epithelial ion and water transport and by regulation of hormones and humoral agents. The kidney synthesizes dopamine from circulating or filteredl‐DOPA independently from innervation. The major determinants of the renal tubular synthesis/release of dopamine are probably sodium intake and intracellular sodium. Dopamine exerts its actions via two families of cell surface receptors, D1‐like receptors comprising D1R and D5R, and D2‐like receptors comprising D2R, D3R, and D4R, and by interactions with other G protein‐coupled receptors. D1‐like receptors are linked to vasodilation, while the effect of D2‐like receptors on the vasculature is variable and probably dependent upon the state of nerve activity. Dopamine secreted into the tubular lumen acts mainly via D1‐like receptors in an autocrine/paracrine manner to regulate ion transport in the proximal and distal nephron. These effects are mediated mainly by tubular mechanisms and augmented by hemodynamic mechanisms. The natriuretic effect of D1‐like receptors is caused by inhibition of ion transport in the apical and basolateral membranes. D2‐like receptors participate in the inhibition of ion transport during conditions of euvolemia and moderate volume expansion. Dopamine also controls ion transport and blood pressure by regulating the production of reactive oxygen species and the inflammatory response. Essential hypertension is associated with abnormalities in dopamine production, receptor number, and/or posttranslational modification. © 2011 American Physiological Society.Compr Physiol1:1075‐1117, 2011.
Physiological and Pathological Angiogenesis in the Adult Pulmonary Circulation
Authors: McLoughlin Paul , Keane Michael P. 
Published: July 2011

AbstractAngiogenesis occurs during growth and physiological adaptation in many systemic organs, for example, exercise‐induced skeletal and cardiac muscle hypertrophy, ovulation, and tissue repair. Disordered angiogenesis contributes to chronic inflammatory disease processes and to tumor growth and metastasis. Although it was previously thought that the adult pulmonary circulation was incapable of supporting new vessel growth, over that past 10 years new data have shown that angiogenesis within this circulation occurs both during physiological adaptive processes and as part of the pathogenic mechanisms of lung diseases. Here we review the expression of vascular growth factors in the adult lung, their essential role in pulmonary vascular homeostasis and the changes in their expression that occur in response to physiological challenges and in disease. We consider the evidence for adaptive neovascularization in the pulmonary circulation in response to alveolar hypoxia and during lung growth following pneumonectomy in the adult lung. In addition, we review the role of disordered angiogenesis in specific lung diseases including idiopathic pulmonary fibrosis, acute adult distress syndrome and both primary and metastatic tumors of the lung. Finally, we examine recent experimental data showing that therapeutic enhancement of pulmonary angiogenesis has the potential to treat lung diseases characterized by vessel loss. © 2011 American Physiological Society.Compr Physiol1:1473‐1508, 2011.