bluuebunny/crossref_metadata_2025 huggingface dataset:
Pseudoaneurysm after transradial cardiac catheterization: Case series and review of the literature
Authors: Collins Nicholas , Wainstein Rodrigo , Ward Michael , Bhagwandeen Rohan , Dzavik Vladimir
Published: July 2011

Introduction: Radial artery access for diagnostic and therapeutic procedures offers clear advantages in terms of vascular complications. While radial artery occlusion may occasionally complicate radial artery access, new methods of hemostasis are now utilized to avoid this complication. In contrast, pseudoaneurysm following radial artery access is an extremely uncommon complication. Methods: We describe a series of patients who developed radial artery pseudoaneurysm after their procedure. Results: Five patients developed radial pseudoaneurysm after diagnostic and interventional procedures, likely reflecting inadequate hemostasis following the procedure and delayed bleeding complicating systemic anticoagulation. Conclusions: While uncommon, radial artery pseudoaneurysm may complicate cardiac catheterization procedures, with anticoagulation an important contributor. The clinical presentation, likely precipitating mechanisms and treatment options are discussed. © 2011 Wiley Periodicals, Inc.
Quality improvement in the door‐to‐balloon times for ST‐elevation myocardial infarction patients presenting without chest pain
Authors: Borden William B. , Fennessy Michelle M. , O'Connor Anne M. , Mulliken Robert A. , Lee Linda , Nathan Sandeep , Nichols Jearlyn , Lopez John J.
Published: July 2011

Objective: To assess a quality improvement initiative aimed at minimizing door‐to‐balloon (DTB) times for ST‐elevation myocardial infarction (STEMI) patients presenting without chest pain. Background: Timely percutaneous coronary intervention (PCI) is the cornerstone of STEMI care. The absence of chest pain delays PCI. Improvements in DTB times may need to focus on atypical presentation patients. Methods: We compared DTB times on all STEMI patients admitted through the emergency department who underwent PCI before (Phase I; October 2004–June 2007) and after (Phase II; July 2007–October 2009) the quality improvement effort, which mandated rapid electrocardiogram (ECG) triage for an expanded list of presenting symptoms. Results: In Phase I (69 patient, 60 with chest pain), patients with chest pain had a shorter mean time to first ECG (ECG Interval) by 32.0 min (P < 0.01) and nonsignificantly faster mean DTB time by 42.0 min (P = 0.07) compared to patients who presented without chest pain. In Phase II (62 patients, 56 with chest pain) compared to Phase I, mean ECG interval decreased by 44 min (P = 0.02) and mean DTB time by 99 min (P = 0.01) in patients without chest pain, eliminating the differences in ECG intervals between typical and atypical presentations (12 min vs. 11 min, P = 0.91). Multivariable analysis controlling for on/off hours and patient characteristics confirmed these findings. Conclusions: A simple modification of emergency room ECG triage protocol, which expands indications for rapid ECG performance, was successful in improving rapid reperfusion for patients with STEMI presenting without chest pain. © 2011 Wiley‐Liss, Inc.
Reduced antiplatelet therapy after drug‐eluting stenting: Multicenter janus flex carbostent implantation with short dual antiplatelet treatment for 2 or 6 months—matrix study
Authors: Cassese Salvatore , De Luca Giuseppe , Villari Bruno , Berti Sergio , Bellone Pietro , Alfieri Alfonso , Montinaro Antonio , Quaranta Gaetano , Marraccini Paolo , Piscione Federico ,   on behalf of MATRIX Study Investigators
Published: July 2011

Objectives: The Multicentre registry with Antiplatelet TReatment two–sIX months (MATRIX) evaluated safety and efficacy at 12‐month follow‐up of Janus Flex stenting with 2‐ or 6‐month dual antiplatelet therapy (DAT) period. Background: There are no data of Janus Flex stent (Carbostent and Implantable Devices—CID, Saluggia, Italy), a polymer‐free, tacrolimus‐eluting coronary stent, followed by short‐term DAT, in daily practice. Methods: Patients were prospectively enrolled at 12 high‐volume procedures centres. After stenting, four sites prescribed 2‐month DAT, eight sites 6‐month DAT. Major adverse cardiac events (MACE) and stent thrombosis (ST) rate was evaluated at 12‐month follow‐up, for entire population, as well as for 2‐ and 6‐month DAT groups, distinctly. MACE included cardiac death, myocardial infarction (MI), and target lesion revascularization (TLR). Results: From March 2007 to June 2008, 572 patients (mean age 64.91 ± 11 years, 77.45% males) were enrolled. After successful stenting, 12‐month follow‐up showed a 12.74% MACE occurrence (cardiac death 0.98%; MI 3.13%; TLR 8.62%), with good Janus Flex safety profile confirmed by only two (0.39%) ST. After adjustment for potential confounding, no significant differences were noted at 12‐month follow‐up among 2‐ or 6‐month DAT groups (MACE—8.99% versus 12.47%, P = 0.16; cardiac death—0.54% versus 1.14%, P = 0.52; MI—2.38% versus 2.71%, P = 0.83; TLR—5.66% versus 10.60%, P = 0.20; ST—0% versus 0.55%, P = 0.99). At multivariable analysis, DAT time duration was not an independent risk factor for adverse events (adjusted HR 0.47, 95% confidence interval 0.16–1.35, P = 0.16). Conclusions: Janus Flex coronary stenting, followed by short DAT, is safe and feasible, without differences between 2‐ and 6‐month DAT groups. A randomized trial confirming these encouraging data is needed. © 2011 Wiley Periodicals, Inc.
Percutaneous left main coronary disease treatment without on‐site surgery back‐up in patients with acute coronary syndromes
Authors: Gagnor Andrea , Tomassini Francesco , Romagnoli Enrico , Infantino Vincenzo , Rosa Brusin Maria Cristina , Maria Cristina , Tripodi Rosario , Sangiorgi Giuseppe , Varbella Ferdinando
Published: July 2011

Background: Best revascularization strategy in patients with acute coronary syndromes (ACS) and unprotected left main (ULM) coronary disease is still debate reflecting lack of convincing data. Objectives: To assess clinical feasibility and efficacy of ULM percutaneous coronary intervention (PCI) in patients with ACS and describe the practice of a center without on‐site surgical back‐up over a 7‐year period. Methods: Data on high‐risk patients with ACSs undergoing percutaneous ULM treatment were prospectively collected in an independent registry. Primary end‐points of this study were immediate and long‐term outcomes expressed as target lesion failure (TLF, composite of cardiac death, myocardial infarction (MI), and target lesion revascularization). Results: Between January 2003 and January 2010, 200 consecutive patients were included in this study. Angiographic success was obtained in 95% of patients but procedural success was 87% primarily affected by an 11% of in‐hospital cardiac mortality. At median follow‐up of 26 months (IQ 10–47), the overall TLF rate was 28.5%, with 16.0% of cardiac death, 7.0% of MI, and 10.5% of clinically driven target lesion revascularization rates. Cumulative definite/probable stent thrombosis was 3.5%. Elevated EuroSCORE value and pre‐procedural hemodynamic instability were the strongest predictors of TLF. Temporal trend analysis showed progressive but not significant improvement for both immediate (P = 0.110) and long‐term (P = 0.073) outcomes over the study period. Conclusions: This single‐center study based on current clinical practice in patient with ULM disease and ACS confirmed PCI as feasible revascularization strategy in absence of on‐site cardio‐thoracic support. Nevertheless, the outcome of these high‐risk patients is still hampered by a sensible in‐hospital mortality rate. © 2011 Wiley Periodicals, Inc.
Lack of long‐term clinical benefit of thrombus aspiration during primary percutaneous coronary intervention with paclitaxel‐eluting stents or bare‐metal stents: Post‐hoc analysis of the PASSION‐trial
Authors: Vink Maarten A. , Dirksen Maurits T. , Tijssen Jan G.P. , Suttorp Maarten J. , Patterson Mark S. , van Geloven Nan , Ijsselmuiden Alexander J. , Slagboom Ton , Kiemeneij Ferdinand , Laarman Gerrit J.
Published: July 2011

Background: Although current clinical guidelines recommend the use of thrombus aspiration (TA) during primary percutaneous coronary intervention (PPCI), previous studies evaluating TA demonstrated contradictory results. The aim of this study was to evaluate long‐term clinical outcome after TA in adjunct to PPCI for acute ST‐segment myocardial infarction (STEMI), as compared with conventional treatment, with the use of paclitaxel‐eluting stents or bare‐metal stents. Methods: We analyzed data of the PASSION trial, in which 619 patients with STEMI were randomly assigned to a paclitaxel‐eluting stent or a bare‐metal stent. TA was performed in 311 patients (50.2%). Clinical endpoints at 2 years were compared between patients who received TA during PPCI with patients who underwent conventional PPCI. The primary outcome of interest was a composite of cardiac death, recurrent myocardial infarction (MI), or target‐lesion revascularization (TLR). A propensity score model was made to account for baseline differences that could have affected the probability of performing TA. Results: Complete follow‐up was available for 598 patients (96.6%). The cumulative incidence of the combined outcome measure of cardiac death, recurrent MI, or TLR was 40 (13.0%) in the TA group and 41 (13.5%) in the conventional PPCI group (HR 0.96; 95% CI 0.62–1.47; P = 0.84). Also after adjusting for propensity score, no significant difference in event rate was observed between both treatment groups. Conclusions: In this post‐hoc analysis of the PASSION trial, TA in adjunct to PPCI did not affect rates of major adverse cardiac events at 2 years follow‐up, as compared with conventional PPCI. © 2011 Wiley Periodicals, Inc.
Transcatheter aortic valve implantation when classical access routes are unavailable
Authors: Mouillet Gauthier , Desgranges Pascal , Teiger Emmanuel
Published: July 2011

A 90‐year‐old woman with symptomatic degenerative aortic stenosis had a logistic Euroscore greater than 53.29%, indicating a high surgical risk. She was therefore advised to undergo transcatheter aortic valve implantation. Both iliac arteries showed subocclusive calcifications, and the left subclavian artery was narrow and calcified. The left common carotid (LCC) artery was chosen as the access route. After surgical exposure of the LCC artery, the Corevalve Revalving 29‐mm bioprosthesis was implanted successfully. No access‐site complications occurred. In our experience, a substantial proportion of elderly patients have vascular lesions precluding use of the femoral route. Brachiocephalic access routes may be valuable when no other options are available. © 2011 Wiley Periodicals, Inc.
Treatment of a degenerative stenosed CoreValve® aortic bioprosthesis by transcatheter valve‐in‐valve insertion
Authors: Hammerstingl Christoph , Nickenig Georg , Grube Eberhard
Published: July 2011

Background: Transcatheter aortic valve insertion (TAVI) is an emerging therapy in patients at high risk for open heart surgery. The long‐term durability of the bioprosthesis is unknown. This is the first report of a severely degeneratively stenosed 2nd generation 26 mm CoreValve® aortic bioprosthesis which occurred five and a half years after TAVI. Methods and Results: A 92‐year‐old patient presented with decompensated heart failure NYHA class IV, pulmonary edema, and severe pulmonary hypertension. Echocardiography revealed critical AV‐stenosis due to heavily calcified bioprosthetic valve leaflets. Due to high surgical risk with an EuroSCORE of 64.97% and a STS‐mortality score of 27.0%, we decided to attempt a valve‐in‐valve insertion of a 3rd generation CoreValve® prosthesis of the same size. Following the delicate retrograde passage of the calcified valve with a preformed stiff wire, balloon valvuloplasty of the severely stenosed CoreValve® prosthesis under rapid right ventricular pacing was complicated by two balloon catheter ruptures. Insertion of the 3rd generation CoreValve® prosthesis of the same size was quite complex but finally it was successfully completed. There was mild periprosthetic regurgitation and significant decrease in transaortic pressure without residual transvalvular gradient immediately after TAVI. Echocardiography and clinical follow‐up at 72 hr after TAVI confirmed excellent valve function with a decrease in systolic pulmonary artery pressure from 70 mm Hg to 35 mm Hg, increase in LV‐EF from 35% to 45%, and improvement of functional status from NYHA IV to NYHA II. The patient was discharged in good medical conditions at day eight. Conclusion: Degenerative stenosis of a CoreValve® bioprothesis may be observed during long‐term follow‐up after successful TAVI for the treatment of severe aortic valve stenosis. A second valve‐in‐valve insertion appears feasible but may require particular interventional approaches. © 2011 Wiley Periodicals, Inc.
3‐D guidance of complex pulmonary artery stent placement using reconstructed rotational angiography with live overlay
Authors: Fagan Thomas , Kay Joseph , Carroll John , Neubauer Anne
Published: July 2011

Technologies which allow rotational angiographic image acquisition and three dimensional (3‐D) vascular reconstruction with subsequent fluoroscopic registration for live 3‐D image overlay are rapidly being adopted. We present the first use of rotational angiography with integrated 3‐D image overlay for guidance during complex pulmonary artery stent placement. Technical considerations, advantages, and limitations of this procedural strategy are discussed. © 2011 Wiley Periodicals, Inc.
Excellent Correlation between Drug Release and Portal Size in Metalla‐Cage Drug‐Delivery Systems
Authors: Barry Nicolas P. E. , Zava Olivier , Dyson Paul J. , Therrien Bruno
Published: July 2011

A series of large cationic hexanuclear metalla‐prisms, [Ru6(p‐iPrC6H4Me)6(tpt)2(donq)3]6+, [Ru6(p‐iPrC6H4Me)6(tpt)2(doaq)3]6+ and [Ru6(p‐iPrC6H4Me)6(tpt)2(dotq)3]6+, composed of p‐cymene–ruthenium building blocks bridged by OO∩OO ligands (donq=5,8‐dioxido‐1,4‐naphthoquinonato; doaq=5,8‐dioxido‐1,4‐anthraquinonato, dotq=6,11‐dioxido‐5,12‐naphthacenedionato) and connected by two 2,4,6‐tripyridin‐4‐yl‐1,3,5‐triazine (tpt) panels, which encapsulate the guest molecules 1‐(4,6‐dichloro‐1,3,5‐triazin‐2‐yl)pyrene and Pd(acac)2, have been prepared. The host–guest properties of these water‐soluble delivery systems were studied in solution by NMR and fluorescence spectroscopy, providing the stability constants (K) for these host–guest systems. Moreover, the ability of the hosts to deliver the guests into cancer cells was evaluated and the uptake mechanism studied; the rate of release of the guest molecule was found to depend on the portal size of the host.
Selective Photocatalytic Oxidation of Alcohols to Aldehydes in Water by TiO2 Partially Coated with WO3
Authors: Tsukamoto Daijiro , Ikeda Makoto , Shiraishi Yasuhiro , Hara Takayoshi , Ichikuni Nobuyuki , Tanaka Shunsuke , Hirai Takayuki
Published: July 2011

Semiconductor TiO2 particles loaded with WO3 (WO3/TiO2), synthesized by impregnation of tungstic acid followed by calcination, were used for photocatalytic oxidation of alcohols in water with molecular oxygen under irradiation at λ>350 nm. The WO3/TiO2 catalysts promote selective oxidation of alcohols to aldehydes and show higher catalytic activity than pure TiO2. In particular, a catalyst loading 7.6 wt % WO3 led to higher aldehyde selectivity than previously reported photocatalytic systems. The high aldehyde selectivity arises because subsequent photocatalytic decomposition of the formed aldehyde is suppressed on the catalyst. The TiO2 surface of the catalyst, which is active for oxidation, is partially coated by the WO3 layer, which leads to a decrease in the amount of formed aldehyde adsorbed on the TiO2 surface. This suppresses subsequent decomposition of the aldehyde on the TiO2 surface and results in high aldehyde selectivity. The WO3/TiO2 catalyst can selectively oxidize various aromatic alcohols and is reusable without loss of catalytic activity or selectivity.
The Role of Oxidative Etching in the Synthesis of Ultrathin Single‐Crystalline Au Nanowires
Authors: Kisner Alexandre , Heggen Marc , Fernández Enrique , Lenk Steffi , Mayer Dirk , Simon Ulrich , Offenhäusser Andreas , Mourzina Yulia
Published: July 2011

The fabrication of ultrathin single‐crystal Au nanowires with high aspect ratio and that are stable in air is challenging. Recently, a simple wet‐chemical approach using oleylamine has been reported for the synthesis of Au nanowires with micrometer length and 2 nm in diameter. Despite efforts to understand the mechanism of the reaction, an ultimate question about the role of oxygen (O2) during the synthesis remained unclear. Here we report that the synthesis of ultrathin Au nanowires employing oleylamine is strongly affected by the amount of O2 absorbed in the reaction solution. Saturating the solution with O2 leads to both a high‐yield production of nanowires and an increase in their length. Nanowires with diameters of about 2 nm and lengths of 8 μm, which corresponds to an aspect ratio of approximately 4000, were produced. The role of oxygen is attributed to the enhanced oxidation of twin defects on Au nanoparticles formed in the first stage of the reaction. Understanding the role of oxidative etching is crucial to significantly increasing the yield and the length of ultrathin Au nanowires.
A Highly Sensitive and Selective Fluorescent Probe for Cyanide Based on the Dissolution of Gold Nanoparticles and Its Application in Real Samples
Authors: Lou Xiaoding , Zhang Yi , Qin Jingui , Li Zhen
Published: July 2011

We report a simple fluorescence method for detection of cyanide sensitively and selectively based on the dissolution of polymer‐coated gold nanoparticles by cyanide. The lowest concentration for quantification of cyanide ions was 3.0×10−7 M, and other common anions nearly have no influence. Furthermore, several real water samples spiked with cyanide, including local groundwater, tap water, boiled water, and lake water, were analyzed, and the experimental results demonstrated that our sensing system worked well in the above water samples, with a good linear correlation.
Multicomponent Assembly of Cavitand‐Based Polyacylhydrazone Nanocapsules
Authors: Lin Zhihua , Emge Thomas J. , Warmuth Ralf
Published: July 2011

The thermodynamically controlled syntheses of different di‐, tetra‐, and hexacavitand polyacylhydrazone nanocapsules are reported. [2+4]‐, [4+8]‐, and [6+12]‐nanocapsules assemble upon reacting a tetraformyl cavitand with two equivalents of isophthalic dihydrazide, or terephthalic dihydrazide in the presence of trifluoroacetic acid, whereby the building blocks are linked together through 8, 16, or 24 newly formed acylhydrazone bonds. Futhermore, the reaction of the tetraformylcavitands with different trigonal planar trihydrazides, simultaneously leads to the formation of [2+4]‐ and [6+8]‐nanocapsules in varying ratios that depend on the cavitand to trihydrazide ratio and the nature of the cavitand and trihydrazide building blocks. The product ratios are rationalized with the different conformational strain of the acylhydrazone linkages in these nanocapsules. Diffusion NMR experiments with the hexacavitand polyacylhydrazone nanocapsules yield solvodynamic radii that range from 1.6 to 2.5 nm, consistent with estimates from force field calculations, and support, that these capsules have solvent filled, spherical interiors, the sizes of which approaches those of smaller proteins.
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

Controlled 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

Two 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

BACKGROUND:

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

The 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

The 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

Modern 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

The 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

We 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

The 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

As 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

By 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

This 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

The 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

Dopamine 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

Angiogenesis 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.
Endocytosis of Environmental and Engineered Micro‐ and Nanosized Particles
Authors: Gehr Peter , Clift Martin J.D , Brandenberger Christina , Lehmann Andrea , Herzog Fabian , Rothen‐Rutishauser Barbara
Published: July 2011

There are many studies with cells to find out how particles interact with them. In contrast to micronsized particles, which are actively taken up by phagocytosis or macropinocytosis, nanosized particles may be taken up by cells through different endocytic pathways or by another, yet to be defined mechanism. There is increasing evidence that it is the nanosized particles, which are a particular risk because of their high content of organic chemicals and their pro‐oxidative potential due to the high surface‐to‐volume ratio of the particles as compared to the bulk material. It is the goal of this article to create an understanding for the interaction of particles with biological systems, with particular consideration of the interaction of nanoparticles (NPs) with lung cells. One is attempting to understand, how NPs interact with cellular membranes, as it is hardly known, how they are taken up by cells, how they are trafficking in cells, and how they interact with subcellular compartments, such as with mitochondria or with the nucleus. Cells tend to defend themselves against any foreign material, which is taken up. In general, they try to eliminate particulate intruders and this is what they usually manage with micronsized particles. However, with NPs it is different. NPs may not be eliminated easily, and, hence may stimulate the cells to react in an unfavorable way. What we can learn is that NPs behave differently than microparticles. © 2011 American Physiological Society.Compr Physiol1:1159‐1174, 2011.
Pathophysiology of the Diabetic Kidney
Authors: Vallon Volker , Komers Radko
Published: July 2011

Diabetes mellitus contributes greatly to morbidity, mortality, and overall health care costs. In major part, these outcomes derive from the high incidence of progressive kidney dysfunction in patients with diabetes making diabetic nephropathy a leading cause of end‐stage renal disease. A better understanding of the molecular mechanism involved and of the early dysfunctions observed in the diabetic kidney may permit the development of new strategies to prevent diabetic nephropathy. Here we review the pathophysiological changes that occur in the kidney in response to hyperglycemia, including the cellular responses to high glucose and the responses in vascular, glomerular, podocyte, and tubular function. The molecular basis, characteristics, and consequences of the unique growth phenotypes observed in the diabetic kidney, including glomerular structures and tubular segments, are outlined. We delineate mechanisms of early diabetic glomerular hyperfiltration including primary vascular events as well as the primary role of tubular growth, hyperreabsorption, and tubuloglomerular communication as part of a “tubulocentric” concept of early diabetic kidney function. The latter also explains the “salt paradox” of the early diabetic kidney, that is, a unique and inverse relationship between glomerular filtration rate and dietary salt intake. The mechanisms and consequences of the intrarenal activation of the renin‐angiotensin system and of diabetes‐induced tubular glycogen accumulation are discussed. Moreover, we aim to link the changes that occur early in the diabetic kidney including the growth phenotype, oxidative stress, hypoxia, and formation of advanced glycation end products to mechanisms involved in progressive kidney disease. © 2011 American Physiological Society.Compr Physiol1:1175‐1232, 2011.