bluuebunny/crossref_metadata_2025 huggingface dataset:
Randomized comparison of endothelial progenitor cells capture stent versus cobalt‐chromium stent for treatment of ST‐elevation myocardial infarction. Six‐month clinical, angiographic, and IVUS follow‐up
Authors: Bystroň Marian , Červinka Pavel , Špaček Radim , Kvašňák Martin , Jakabčin Jozef , Červinková Michaela , Kala Petr , Widimský Petr
Published: May 2010

Purpose: The aim of this trial was to assess the feasibility and safety of endothelial progenitor cells capture (EPC) stent in the treatment of acute ST‐elevation myocardial infarction (STEMI) when compared with cobalt‐chromium stents (CoCr). Methods: Between July 2006 and May 2008, 100 patients with single vessel disease undergoing primary PCI for STEMI were randomly assigned to receive either EPC stent (N = 50) or CoCr stent (N = 50). High‐pressure stent implantation was carried out in both groups. Dual antiplatelet treatment was administered for 30 days in both groups. All patients underwent 6‐month clinical, angiographic, and IVUS follow‐up. Results: The rate of major adverse cardiovascular events (MACEs) at 30 days was comparable in both groups. At 6‐month follow‐up, the rates of MACEs and TLR in the EPC stent group when compared with CoCr stent were 24% vs.10%; P = 0.06 and 14% vs. 4%; P = 0.08, respectively. There were three cases (6%) of stent thrombosis (ST) in the EPC stent group versus none in CoCr group. Conclusion: The use of EPC capture stents in the setting of STEMI is feasible and safe in terms of 30‐days outcome. However, at the 6‐month follow‐up, we found a trend of higher rates of MACE and TLR in the EPC stent capture group compared to CoCr stents. The study does not support the use of EPC capture stents with short duration dual antiplatelet therapy in patients with STEMI. Future randomized studies with large sample sizes would be necessary to demonstrate the safety of such approach. © 2010 Wiley‐Liss, Inc.
Aortic coarctation by cardiovascular CT angiography
Authors: Gopal Ambarish , Loewinger Lee , Budoff Matthew J.
Published: May 2010

The patient is a 12‐year‐old boy who underwent prospectively gated step‐and‐shoot chest CT (computed tomographic) angiography with a 64‐multislice CT scanner (64‐MSCT) for a preliminary diagnosis of coarctation of aorta. The data was acquired in a manner to significantly minimize radiation to the patient, including use of 80 kVp (rather than 120 kVp, much more commonly employed in cardiac CT), low mA (120 mA, rather than typical 400 mA), and prospective acquisition using a VCT 64 detector scanner (General Electric, Milwaukee, WI) (Figs. 1 and 2). Total radiation dose was 0.9 mSv, despite imaging from sternal notch to liver. Findings included dilated ascending aorta (43 mm diameter) and a total coarctation of descending aorta with very well‐developed collaterals. The left internal mammary artery and right internal mammary artery were noted to be very large (7 mm diameter). © 2010 Wiley‐Liss, Inc.
A randomized comparison of TR band and radistop hemostatic compression devices after transradial coronary intervention
Authors: Rathore Sudhir , Stables Rodney H. , Pauriah Maheshwar , Hakeem Abdul , Mills Joseph D. , Palmer Nick D. , Perry Raphael A. , Morris John L.
Published: May 2010

Background: The transradial route for coronary intervention has proven to be safe, effective, and widely applicable in different clinical situations. Several compressive hemostatic devices have been introduced that have shown to be safe and are effective in achieving hemostasis. Methods: Seven hundred ninety patients were randomly assigned to receive either TR band or Radistop hemostatic compression devices after transradial coronary procedure. The outcome measures were patient tolerance of the device, local vascular complications, and the time taken to achieve hemostasis. Results: The mean age was 62.88 years, and 74.2% of the patients were men. Patient age, height, weight, wrist circumference, body mass index, male sex, hypertension, diabetes, hypercholesterolemia, and smoking incidences were similar in both groups. There were significantly more patients reporting no discomfort in the TR band group compared to the Radistop group (77% vs. 61%; P = 0.0001). Patients in the Radistop group reported significantly more pain across all categories of severity and three patients in the Radistop group were crossed over to TR band because of severe discomfort. Oozing and ecchymosis were seen in about 16% of the patients. Local small hematoma and large hematoma were seen in 5.4% and 2.2% patients respectively, and similar in both groups. Radial artery occlusion at the time of discharge was seen in 9.2% of the patients though only 6.8% showed persistent occlusion at the time of follow‐up. The time taken to achieve hemostasis was significantly longer in the TR Band group (5.32 ± 2.29 vs. 4.83 ± 2.23 hr; P = 0.004). There was significantly higher incidence of radial artery occlusion in patients with smaller wrist circumference, the patients who experienced radial artery spasm during the procedure, and patients with no heparin administration during the procedure. Conclusions: We have shown in a randomized comparison of Radistop and TR band that both devices are safe and effective as hemostatic compression devices following transradial procedures. However, more patients felt discomfort with the Radistop device and the time taken to achieve hemostasis was longer with TR band. © 2010 Wiley‐Liss, Inc.
Histopathology of aspirated thrombus and its association with ST‐segment recovery in patients undergoing primary percutaneous coronary intervention with routine thrombus aspiration
Authors: Verouden Niels J.W. , Kramer Miranda C. , Li XiaoFei , Meuwissen Martijn , Koch Karel T. , Henriques José P.S. , Baan Jan , Vis Marije M. , Piek Jan J. , van der Wal Allard C. , Tijssen Jan G.P. , de Winter Robbert J.
Published: May 2010

Background: In patients with ST‐segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) with thrombus aspiration, the histopathology of aspirated thrombus was previously related to long‐term mortality. In this study, we sought to investigate the association between histopathology of aspirated thrombus and ST‐segment recovery, a marker of microvascular dysfunction, immediately at the end of the PCI procedure. Methods: We included 892 STEMI patients who underwent primary PCI with routine thrombus aspiration and for whom combined data on histopathology of aspirated thrombus and ST‐segment recovery were available. Patients were categorized according to histopathology of aspirated thrombus: fresh only (<1 day), older (>1 day), or no material aspirated. ST‐segment recovery was defined as incomplete if <50%. Results: Incomplete ST‐segment recovery occurred in 134 of 363 patients (37%) with fresh thrombus, in 104 of 238 patients (44%) with older thrombus, and in 142 of 291 patients (49%) with no material. Unadjusted odds ratios for incomplete ST‐segment recovery of patients with older thrombus and no material, when compared with patients with fresh thrombus, were 1.33 (95% CI, 0.95–1.85; P = 0.097) and 1.63 (95% CI 1.19–2.23; P = 0.002), respectively. Both associations were unchanged after multivariable adjustment for clinical predictors of ST‐segment recovery. ST‐segment recovery was a strong predictor of long‐term mortality, independent of the histopathology of aspirated thrombus. Conclusions: This study shows that ST‐segment recovery immediately at the end of the PCI procedure was a significant prognosticator, independent of the histopathology of aspirated thrombus. We found that the histopathology of aspirated thrombus (fresh, older, no material) was associated with ST‐segment recovery in STEMI patients undergoing primary PCI with thrombus aspiration. © 2010 Wiley‐Liss, Inc.
Entrapped coronary angioplasty stent balloon due to nondeflation: Percutaneous retrieval by a simple technique
Authors: Girish M.P. , Gupta Mohit D. , Tyagi Sanjay
Published: May 2010

Complication due to hardware failure may happen even in the most straightforward interventional procedures. We report an unusual complication of nondeflation of coronary stent balloon entrapped within the coronary tree. The nondeflated balloon was retrieved percutaneously by a simple technique. © 2010 Wiley‐Liss, Inc.
Series of transcatheter valve‐in‐valve implantations in high‐risk patients with degenerated bioprostheses in aortic and mitral position
Authors: Seiffert Moritz , Franzen Olaf , Conradi Lenard , Baldus Stephan , Schirmer Johannes , Meinertz Thomas , Reichenspurner Hermann , Treede Hendrik
Published: May 2010

Objectives: We report our experience with transcatheter valve‐in‐valve implantations in patients with degenerated bioprostheses in aortic and mitral position. Background: Xenograft degeneration is a potential problem after biological valve replacement. Reoperation remains the gold standard with very good short‐ and long‐term results. In selected patients not suitable for surgery however, interventional techniques for valve implantation and repair may be valuable alternative treatment options with regard to the good results of transcatheter valve implantation for native aortic valve stenosis. Methods: Five patients presented with significant xenograft degeneration 15.4 ± 5.2 years after aortic (n = 4) and mitral (n = 1) valve replacement. Mean patient age was 82.0 ± 6.5 years and predicted operative mortality was 55.8% ± 18.9% (logistic EuroSCORE). Transcatheter valve‐in‐valve implantation was performed successfully through a transapical access in all patients. A 23‐mm Edwards Sapien valve was deployed into the degenerated valve prosthesis. Results: Mean transvalvular gradients were reduced from 31.2 ± 17.4 to 19.0 ± 12.4 mm Hg in aortic and from 9 to 3 mm Hg in mitral position without significant regurgitation in any of these patients. Two patients died within 30 days due to low cardiac output and acute hemorrhage, respectively, one of whom presented with a EuroSCORE of 88.9%. Conclusions: With growing need for reoperative valve replacement in elderly patients with disproportional operative risks, transcatheter valve‐in‐valve implantation in aortic and mitral position offers an alternative treatment option. Although valve function after transcatheter implantation was good in all patients, two high risk patients died in the postoperative period due to their significant comorbidities, underscoring the bail‐out character of this procedure. © 2010 Wiley‐Liss, Inc.
Mechanical embolectomy for large vessel ischemic strokes: A cardiologist's experience
Authors: Abelson Mark , Roos Johan
Published: May 2010

Introduction: Large vessel acute ischemic stroke has a poor outcome. Intravenous (IV) thrombolysis is often contra‐indicated and if given, usually ineffective. Mechanical embolectomy is an option in these patients and may be performed by an interventional cardiologist experienced in carotid interventions. Method: Consecutive stroke patients were assessed by the stroke physician and, if eligible, referred for possible mechanical embolectomy using the Merci retriever. All procedures were done by a single cardiologist. Patient information, procedural characteristics and clinical outcomes at 90 days were collected by retrospective chart review. Results: A total of 22 patients were referred for emergency cerebral angiography with 17 undergoing mechanical embolectomy. The mean National Institute of Health Stroke Scale (NIHSS) score was 20.1 and the mean stroke duration was 284 min. Recanalization was successful in 15 (88%) patients. Ten patients (59%) had a good outcome (modified Rankin Score ≤2 at 90 days) and four died (mortality 23%). Three patients had significant intra‐cerebral hemorrhage. There were no other major adverse events. Conclusions: For patients with large vessel occlusion strokes where IV thrombolysis was either contra‐indicated or had failed, mechanical embolectomy performed by an interventional cardiologist had a high recanalization rate with an acceptable clinical outcome and safety profile. © 2010 Wiley‐Liss, Inc.
Unravelling the Reaction Mechanism for the Fast Photocyclisation of 2‐Benzoylpyridine in Aqueous Solvent by Time‐Resolved Spectroscopy and Density Functional Theory Calculations
Authors: Du Yong , Xue Jiadan , Li Ming‐De , Guan Xiangguo , McCamant David W. , Phillips David Lee
Published: May 2010

A combined femtosecond transient absorption (fs‐TA) and nanosecond time‐resolved resonance Raman (ns‐TR3) spectroscopic investigation of the photoreaction of 2‐benzoylpyridine (2‐BPy) in acetonitrile and neutral, basic and acidic aqueous solvents is reported. fs‐TA results showed that the nπ* triplet 2‐BPy is the precursor of the photocyclisation reaction in neutral and basic aqueous solvents. The cis triplet biradical and the cis singlet zwitterionic species produced during the photocyclisation reaction were initially characterised by ns‐TR3 spectroscopy. In addition, a new species was uniquely observed in basic aqueous solvent after the decay of the cis singlet zwitterionic species and this new species was tentatively assigned to the photocyclised radical anion. The ground‐state conformation of 2‐BPy in acidic aqueous solvent is the pyridine nitrogen‐protonated 2‐BPy cation (2‐BPy‐NH+) rather than the neutral form of 2‐BPy. After laser photolysis, the singlet excited state (S1) of 2‐BPy‐NH+ is generated and evolves through excited‐state proton transfer (ESPT) and efficient intersystem crossing (ISC) processes to the triplet exited state (T1) of the carbonyl oxygen‐protonated 2‐BPy cation (2‐BPy‐OH+) and then photocyclises with the lone pair of the nitrogen atom in the heterocyclic ring. Cyclisation reactions take place both in neutral/basic and acidic aqueous solvents, but the photocyclisation mechanisms in these different aqueous solvents are very different. This is likely due to the different conformation of the precursor and the influence of hydrogen‐bonding of the solvent on the reactions.
Cyclic Carbonate Synthesis Catalysed by Bimetallic Aluminium–Salen Complexes
Authors: Clegg William , Harrington Ross W. , North Michael , Pasquale Riccardo
Published: May 2010

The development of bimetallic aluminium–salen complexes [{Al(salen)}2O] as catalysts for the synthesis of cyclic carbonates (including the commercially important ethylene and propylene carbonates) from a wide range of terminal epoxides in the presence of tetrabutylammonium bromide as a cocatalyst is reported. The bimetallic structure of one complex was confirmed by X‐ray crystallography. The bimetallic complexes displayed exceptionally high catalytic activity and in the presence of tetrabutylammonium bromide could catalyse cyclic carbonate synthesis at atmospheric pressure and room temperature. Catalyst‐reuse experiments demonstrated that one bimetallic complex was stable for over 60 reactions, though the tetrabutylammonium bromide decomposed in situ by a retro‐Menschutkin reaction to form tributylamine and had to be regularly replaced. The mild reaction conditions allowed a full analysis of the reaction kinetics to be carried out and this showed that the reaction was first order in aluminium complex concentration, first order in epoxide concentration, first order in carbon dioxide concentration (except when used in excess) and unexpectedly second order in tetrabutylammonium bromide concentration. Further kinetic experiments demonstrated that the tributylamine formed in situ was involved in the catalysis and that addition of butyl bromide to reconvert the tributylamine into tetrabutylammonium bromide resulted in inhibition of the reaction. The reaction kinetics also indicated that no kinetic resolution of racemic epoxides was possible with this class of catalysts, even when the catalyst was derived from a chiral salen ligand. However, it was shown that if enantiomerically pure styrene oxide was used as substrate, then enantiomerically pure styrene carbonate was formed. On the basis of the kinetic and other experimental data, a catalytic cycle that explains why the bimetallic complexes display such high catalytic activity has been developed.
Optically Degradable Dendrons for Temporary Adhesion of Proteins to DNA
Authors: Kostiainen Mauri A. , Kotimaa Juha , Laukkanen Marja‐Leena , Pavan Giovanni M.
Published: May 2010

Experimental studies and molecular dynamics modeling demonstrate that multivalent dendrons can be used to temporarily glue proteins and DNA together with high affinity. We describe N‐maleimide‐cored polyamine dendrons that can be conjugated with free cysteine residues on protein surfaces through 1,4‐conjugate addition to give one‐to‐one protein–polymer conjugates. We used a genetically engineered cysteine mutant of class II hydrophobin (HFBI) and a single‐chain Fragment variable (scFv) antibody as model proteins for the conjugation reactions. The binding affinity of the protein–dendron conjugates towards DNA was experimentally assessed by using the ethidium bromide displacement assay. The binding was found to depend on the generation of the dendron, with the second generation having a stronger affinity than the first generation. Thermodynamic parameters of the binding were obtained from molecular dynamics modeling, which showed that the high binding affinity for each system is almost completely driven by a strong favorable binding enthalpy that is opposed by unfavorable binding entropy. A short exposure to UV (λ≈350 nm) can cleave the photolabile o‐nitrobenzyl‐linked binding ligands from the surface of the dendron, which results in loss of the multivalent binding interactions and triggers the release of the DNA and protein. The timescale of the release is very rapid and the binding partners can be efficiently released after 3 min of UV exposure.
Comparison of Thiophene–Pyrrole Oligomers with Oligothiophenes: A Joint Experimental and Theoretical Investigation of Their Structural and Spectroscopic Properties
Authors: Oliva María Moreno , Pappenfus Ted M. , Melby Jacob H. , Schwaderer Kathryn M. , Johnson Jared C. , McGee Kari A. , da Silva Filho Demetrio A. , Bredas Jean‐Luc , Casado Juan , López Navarrete Juan T.
Published: May 2010

We have prepared a new series of mixed thiophene–pyrrole oligomers to investigate the electronic benefits arising from the combination of these two heterocycles. The oligomers are functionalized with several hexyl and aryl groups to improve both processability and chemical robustness. An analysis of their spectroscopic (absorption and emission), photophysical, electrochemical, solid state, and vibrational properties is performed in combination with quantum‐chemical calculations. This analysis provides relevant information regarding the use of these materials as organic semiconductors. The balance between the high aromatic character of pyrrole and the moderate aromaticity of thiophene allows us to address the impact of the coupling of these heterocycles in conjugated systems. The data are interpreted on the basis of the aromaticity, molecular conformations, ground and excited electronic state structures, frontier orbital topologies and energies, oxidative states, and quinoidal versus aromatic competition.
Structure‐Based Design of Platinum(II) Complexes as c‐myc Oncogene Down‐Regulators and Luminescent Probes for G‐Quadruplex DNA
Authors: Wang Ping , Leung Chung‐Hang , Ma Dik‐Lung , Yan Siu‐Cheong , Che Chi‐Ming
Published: May 2010

A series of platinum(II) complexes with tridentate ligands was synthesized and their interactions with G‐quadruplex DNA within the c‐myc gene promoter were evaluated. Complex 1, which has a flat planar 2,6‐bis(benzimidazol‐2‐yl)pyridine (bzimpy) scaffold, was found to stabilize the c‐myc G‐quadruplex structure in a cell‐free system. An in silico G‐quadruplex DNA model has been constructed for structure‐based virtual screening to develop new PtII‐based complexes with superior inhibitory activities. By using complex 1 as the initial structure for hit‐to‐lead optimization, bzimpy and related 2,6‐bis(pyrazol‐3‐yl)pyridine (dPzPy) scaffolds containing amine side‐chains emerge as the top candidates. Six of the top‐scoring complexes were synthesized and their interactions with c‐myc G‐quadruplex DNA have been investigated. The results revealed that all of the complexes have the ability to stabilize the c‐myc G‐quadruplex. Complex 3 a ([PtIIL2R]+; L2=2,6‐bis[1‐(3‐piperidinepropyl)‐1H‐enzo[d]imidazol‐2‐yl]pyridine, R=Cl) displayed the strongest inhibition in a cell‐free system (IC50=2.2 μM) and was 3.3‐fold more potent than that of 1. Complexes 3 a and 4 a ([PtIIL3R]+; L3=2,6‐bis[1‐(3‐morpholinopropyl)‐1H‐pyrazol‐3‐yl]pyridine, R=Cl) were found to effectively inhibit c‐myc gene expression in human hepatocarcinoma cells with IC50 values of ≈17 μM, whereas initial hit 1 displayed no significant effect on gene expression at concentrations up to 50 μM. Complexes 3 a and 4 a have a strong preference for G‐quadruplex DNA over duplex DNA, as revealed by competition dialysis experiments and absorption titration; 3 a and 4 a bind G‐quadruplex DNA with binding constants (K) of approximately 106–107 dm3 mol−1, which are at least an order of magnitude higher than the K values for duplex DNA. NMR spectroscopic titration experiments and molecular modeling showed that 4 a binds c‐myc G‐quadruplex DNA through an external end‐stacking mode at the 3′‐terminal face of the G‐quadruplex. Intriguingly, binding of c‐myc G‐quadruplex DNA by 3 b is accompanied by an increase of up to 38‐fold in photoluminescence intensity at λmax=622 nm.
Nucleophilic Aromatic Addition Reactions of the Metallabenzenes and Metallapyridinium: Attacking Aromatic Metallacycles with Bis(diphenylphosphino)methane to Form Metallacyclohexadienes and Cyclic η2‐Allene‐Coordinated Complexes
Authors: Zhang Hong , Lin Ran , Hong Guangning , Wang Tongdao , Wen Ting Bin , Xia Haiping
Published: May 2010

The reactions of phosphonium‐substituted metallabenzenes and metallapyridinium with bis(diphenylphosphino)methane (DPPM) were investigated. Treatment of [Os{CHC(PPh3)CHC(PPh3)CH}Cl2(PPh3)2]Cl with DPPM produced osmabenzenes [Os{CHC(PPh3)CHC(PPh3)CH}Cl2{(PPh2)CH2(PPh2)}]Cl (2), [Os{CHC(PPh3)CHC(PPh3)CH}Cl{(PPh2)CH2(PPh2)}2]Cl2 (3), and cyclic osmium η2‐allene complex [Os{CHC(PPh3)CH(η2‐CCH)}Cl2{(PPh2)CH2(PPh2)}2]Cl (4). When the analogue complex of osmabenzene 1, ruthenabenzene [Ru{CHC(PPh3)CHC(PPh3)CH}Cl2(PPh3)2]Cl, was used, the reaction produced ruthenacyclohexadiene [Ru{CHC(PPh3)CHC(PPh3)CH}Cl{(PPh2)CH2(PPh2)}2]Cl2 (6), which could be viewed as a Jackson–Meisenheimer complex. Complex 6 is unstable in solution and can easily be convert to the cyclic ruthenium η2‐allene complexes [Ru{CHC(PPh3)CH(η2‐CCH)}Cl{(PPh2)CH2(PPh2)}2]Cl2 (7) and [Ru{CHC(PPh3)CH(η2‐CCH)}Cl2{(PPh2)CH2(PPh2)}2]Cl (8). The key intermediates of the reactions have been isolated and fully characterized, further supporting the proposed mechanism for the reactions. Similar reactions also occurred in phosphonium‐substituted metallapyridinium [OsCl2{NHC(CH3)C(Ph)C(PPh3)CH}(PPh3)2]BF4 to give the cyclic osmium η2‐allene‐imine complex [OsCl2{NHC(CH3)C(Ph)(η2‐CCH)}{(PPh2)CH2(PPh2)}(PPh3)]BF4 (11).
Synthese mikroporöser Kohlenstoffschäume für katalytische Anwendungen
Authors: Etzold B. , Glenk F. , Schirmer M. , Gütlein S.
Published: May 2010

Mikroporöse Kohlenstoffschäume wurden über die Chlorierung von Carbiden zur Verwendung als strukturierte Katalysatorträger hergestellt. Die selbsttragenden Strukturen zeigten eine enge Mikroporenverteilung, welche Formselektivität induzieren können. Die Eignung dieser Materialien als Katalysatorträger wurde durch Nassimprägnierung von Pulver mit Platin und die Verwendung in einer Modellhydrierung von Olefinen getestet. Es ist anzunehmen, dass die Ergebnisse der Nassimprägnierung und Hydrierung auf Kohlenstoffschaumstrukturen übertragbar sind.
Zeolithkatalyse für die nachhaltige Chemie
Authors: Reschetilowski W.
Published: May 2010

In einer Zeit der begrenzten Verfügbarkeit von Erdöl, Erdgas und Kohle verbunden mit deren gleichzeitig steigendem Weltbedarf wird der Einsatz von alternativen Rohstoffen in der chemischen Industrie unumgänglich. Eine sich anbietende reale Strategie zur Deckung der Bedürfnisse hinsichtlich der benötigten Chemieprodukte und Kraftstoffe stellt die stoffliche Nutzung der Biomasse dar. Bei der Entwicklung neuer katalytischer Verfahren der Stoffwandlung unter Verwendung biobasierter Rohstoffe können wir von den Erfahrungen der modernen Chemieindustrie profitieren, in der viele stoffwandelnde Prozesse mit hocheffektiven Katalysatoren auf der Basis von Zeolithen oder zeolithähnlichen Materialien erfolgreich verlaufen und deshalb auch in Zukunft richtungsweisend bleiben. Anhand ausgewählter aktueller Beispiele werden die bereits erzielten Erfolge der neuen Strategie hinsichtlich des wissenschaftlichen und technischen Fortschritts beim Übergang vom „schwarzen zum grünen Gold”︁ demonstriert.
Zeolithe als Sorptionsmittel
Authors: Unger B. , Schumann K. , Brandt A.
Published: May 2010

Zeolithe bzw. zeolithische Molekularsiebe gehören zu den derzeit bedeutendsten technischen Adsorptionsmitteln. Die Adsorption stellt eine Alternativmöglichkeit zum Trennen von Stoffgemischen oder Reinigen von Stoffen dar. Bei der Stofftrennung durch Adsorption an zeolithischen Molekularsieben nutzt man sowohl die geometrischen als auch die elektronischen Unterschiede der zu trennenden Komponenten aus, wobei ein wesentlicher Vorteil von Zeolithen die Variabilität der Porengrößen ist. Zeolithische Systeme sind auch als Materialien zur Wärme‐ und Kälteerzeugung und zur Energiespeicherung geeignet. In diesem Artikel soll ein praxisorientierter Überblick aus der Sicht der für die Adsorption wichtigsten Zeolithe und deren vielseitige Einsatzgebiete gegeben werden
Neue nanoporöse Molekularsiebmembranen: Zeolithe contra MOFs – Gewinner und Verlierer
Authors: Caro J.
Published: May 2010

Sowohl Zeolith‐ als auch MOF (metal organic framework)‐Membranen sind potentiell in der Lage, ein fluides Gemisch nach Größe und Gestalt der Komponenten aufzutrennen und werden daher als Molekularsiebmembranen bezeichnet. In den letzten Jahren wurden wesentliche Fortschritte bei der Synthese, Charakterisierung und Anwendung von Zeolithmembranen erzielt. Dennoch sind die Fortschritte bei der Einführung von Zeolithmembranen in die industrielle Trenntechnik eher gering. Durch Anwendung der bei der Entwicklung von Zeolithmembranen entwickelten Präparationstechniken wie Seeding, Einsatz grobporöser Träger, Einstellen von Zeta‐Potenzialen während der Synthese, Mikrowellenheizen etc. konnten in vergleichsweise kurzer Zeit wesentliche Fortschritte bei der Entwicklung von MOF‐Molekularsiebmembranen erzielt werden. Als metall‐organisches Hybrid besitzen MOFs eine Reihe anwendungstechnischer Vorzüge, die ihren technischen Einsatz als Gastrennmembran aussichtsreich erscheinen lassen.
Zirkoniumdioxid mit definierter Partikelmorphologie und hierarchisch strukturiertem Porensystem durch kombinierte Exo‐ und Endotemplatsynthese
Authors: Gläser R. , Heinrich A. , With P. , Lutecki M. , Fichtner S. , Böhringer B.
Published: May 2010

Zirkoniumdioxid ist nicht nur thermisch und meachnisch sehr stabil, sondern kann auch mit großer spezifischer Oberfläche und großem spezifischen Porenvolumen hergestellt werden. Dadurch ist es als Katalysatorträger interessant. Die Herstellung von Partikeln mit größeren Abmessungen gelingt über Exotemplatsynthese unter Verwendung von Aktivkohle mit kugelförmigen Partikeln. Der Zusatz eines Endotemplats erzeugt ein zusätzliches Mesoporensytem, so dass Zirkoniumdioxid mit hierarchisch strukturiertem Porensystem und zugleich definierter Partikelmorphologie zugänglich wird.
Mesoporöse Glasmembranen als Modellsysteme zur Untersuchung der Gasdiffusion durch poröse Medien
Authors: Stoltenberg D. , Enke D. , Seidel‐Morgenstern A.
Published: May 2010

Poröse Gläser in Form von Monolithen eignen sich auf Grund ihrer speziellen Eigenschaften als Modellsystem zur Untersuchung von porengrößenabhängigen Effekten. In dieser Studie wurde die Gaspermeation verschiedener adsorbierbarer und nicht adsorbierbarer Gase durch neue mesoporöse Glasmembranen untersucht. Dazu wurden Einzelgasmessungen mit einer modifizierten Wicke‐Kallenbach‐Zelle durchgeführt. Durch die Modifizierung der inneren Oberfläche der Glasmembranen war es möglich die Adsorptions‐ und Diffusionseigenschaften der Membranen zu beeinflussen.
Network models for capillary porous media: application to drying technology
Authors: Metzger T. , Tsotsas E.
Published: May 2010

Network models offer an efficient pore‐scale approach to investigate transport in partially saturated porous materials and are particularly suited to study capillarity. Drying is a prime model application since it involves a range of physical effects: capillary pumping, viscous liquid flow, phase transition, vapor diffusion, heat transfer, but also cracks and shrinkage. This review article gives an introduction to this modern technique addressing required model input, sketching important elements of the computational algorithm and commenting on the nature of simulation results. For the case of drying, it is illustrated how network models can help analyze the influence of pore structure on process kinetics and gain a deeper understanding of the role of individual transport phenomena. Finally, a combination of pore network model and discrete element method is presented, extending the application range to mechanical effects caused by capillary forces.
Spektroskopische Charakterisierung von porösen Materialien – Stand der Technik und Zukunftsperspektiven
Authors: Hartmann M.
Published: May 2010

Spektroskopische Methoden werden vielfältig zur Charakterisierung von porösen Materialien wie Zeolithen, Alumophosphaten, mesoporösen Silicaten und porösen Koordinationspolymeren (MOFs) im Hinblick auf strukturelle und physico‐chemische Eigenschaften eingesetzt. Dieser Beitrag gibt einen Überblick über die zur Verfügung stehenden Methoden und die gewinnbaren Informationen insbesondere im Hinblick auf den Einsatz dieser Materialien als Asorbentien und Katalysatoren.
Metallorganische Gerüstverbindungen (MOFs)
Authors: Kaskel S.
Published: May 2010

Bei der Suche nach immer neuen Adsorbentien mit höheren spezifischen Oberflächen und neuen Funktionalitäten haben insbesondere metallorganische Gerüstverbindungen (Metal‐Organic Frameworks, MOFs) zu enormen Fortschritten beigetragen. Als Applikationen werden heute Gasspeicherung, Gastrennprozesse, Medizintechnik bis hin zu Biomaterialien und Sensorik, aber auch Katalysatoren diskutiert. Daneben existieren auch funktionelle Nischen im Bereich der Optoelektronik, magnetische und ferroelektrische Eigenschaften sind noch wenig erforscht. MOFs sollten nicht als Substituenten für Zeolithe diskutiert werden. Ihre Stärke liegt in der extrem großen Porosität in Kombination mit molekularen Baugruppen, die spezifische Interaktionen mit zu adsorbierenden Molekülen eingehen können. Die modularen Konstruktionsprinzipien der MOFs werden auch auf andere Materialklassen zunehmend übertragen.
The Effect of Sleep Apnea on QT Interval, QT Dispersion, and Arrhythmias
Authors: Barta Kitti , Szabó Zoltán , Kun Csaba , Munkácsy Csaba , Bene Orsolya , Tünde Magyar Mária , Csiba László , Lörincz István
Published: May 2010

Background

QT interval (QT) and QT dispersion (QTd) are electrocardiograph (ECG) parameters for the evaluation of myocardial repolarization. The inhomogeneity of ventricular repolarization is associated with ventricular arrhythmias. An increased QT, QTd, and increased incidence of nocturnal cardiac rhythm disturbances have been described in patients with obstructive sleep apnea (OSA), while other investigators did not find a relationship between ventricular arrhythmias and OSA.

Hypothesis

The aim of this study was to examine the occurrence of ventricular arrhythmias and to measure QT parameters in patients with untreated OSA using an ambulatory Holter‐ECG.

Methods

A total of 25 patients with untreated OSA were studied. After routine biochemical investigation and 2‐dimensional, M‐mode echocardiography, a 24‐hour Holter‐ECG was recorded to detect cardiac arrhythmias and QT parameters. QT parameters were measured by the QT Guard system.

Results

Only the QT interval increased significantly during the nighttime period (nocturnal QT interval: 423.1 ± 34.6 ms, daytime QT interval: 381.6 ± 33.8 ms, 24‐hour QT interval: 394.7 ± 31.1 ms). However, during the nighttime QT interval (422.8 ± 14.9 ms), QTd (31.2 ± 11.0 ms) and QT dispersion (30.5 ± 10.2 ms) did not show any change compared to 24‐hour (QTc interval: 423.7 ± 14.2 ms, QTd: 28.8 ± 9.4 ms, QTcd: 30.5 ± 9.43 ms) and daytime levels (QTc interval: 423.9 ± 14.3 ms, QTd: 27.3 ± 10.7 ms, QTcd: 29.9 ± 11.1 ms). None of the patients had ventricular arrhythmias.

Conclusions

QTd and QTcd did not increase during the nighttime period. Our study did not show an increased risk of ventricular arrhythmias in this population during the monitoring period. Copyright © 2010 Wiley Periodicals, Inc.
Safety of Selective Serotonin Reuptake Inhibitor Use Prior to Coronary Artery Bypass Grafting
Authors: Xiong Glen L. , Jiang Wei , Clare Robert M. , Shaw Linda K. , Smith Peter K. , O'Connor Christopher M. , Ranga K. , Krishnan R. , Kristin Newby L.
Published: May 2010

Background

Selective serotonin reuptake inhibitors (SSRIs) have been shown to increase bleeding risks. This study examined the association of perioperative coronary artery bypass grafting (CABG) bleeding risks and SSRI use prior to CABG.

Hypothesis

SSRI may be associated with increased bleeding risks after CABG resulting in elevated reoperation rates due to bleeding complications.

Methods

Patients who underwent CABG between 1999 and 2003 (n = 4794) were identified in a tertiary medical center. SSRI use (n = 246) was determined using inpatient pharmacy records. Outcomes included primary end point of reoperation due to bleeding complications and other secondary measures. Multivariate regression models were constructed to adjust for baseline differences between SSRI and control groups.

Results

Reoperation due to bleeding complications among SSRI users was not significantly different (odds ratio [OR]: 1.14 (0.52–2.47); P = 0.75) compared to the control group. Other secondary outcomes and 30‐day mortality (2.0% in SSRI vs 2.1% in control group; P = 0.92) between the 2 groups were similar. However, the adjusted total volume of postoperative red blood cell (RBC) units transfused was higher in the SSRI group.

Conclusion

We conclude that there is no compelling evidence to limit the use of SSRIs among patients with coronary artery disease who undergo CABG given the current evidence. Further research may be needed on individual SSRI medications. Copyright © 2010 Wiley Periodicals, Inc.
Symptom Presentation in Patients Hospitalized with Acute Heart Failure
Authors: Goldberg Robert J. , Spencer Frederick A. , Szklo‐Coxe Mariana , Tisminetzky Mayra , Yarzebski Jorge , Lessard Darleen , Gore Joel M. , Gaasch William
Published: May 2010

Objectives

The objectives of this study were to examine the type and frequency of symptoms in patients hospitalized with acute heart failure (HF) as well as the relationship between symptom patterns and patient characteristics, treatment practices, and hospital outcomes in patients hospitalized with decompensated HF.

Methods

The study sample consisted of 4537 residents of the Worcester, MA metropolitan area hospitalized for decompensated HF at 11 greater Worcester medical centers in 1995 and 2000.

Results

The average age of the study sample was 76 years; the majority (57%) were women, and three‐quarters of our patient population had been previously diagnosed with HF. Dyspnea (93%) was the most frequent complaint reported by patients followed by the presence of peripheral edema (70%), cough (51%), orthopnea (37%), and chest pain/discomfort (30%). Patients reporting few cardiac symptoms were less likely to be treated with effective cardiac therapies during hospitalization than patients with multiple cardiac signs and symptoms and experienced higher hospital (9.7% vs. 7.7%) as well as 30‐day (17.1% vs. 10.2%) death rates (P < 0.05).

Conclusions

The results of this study in residents of a large New England community suggest that patients with fewer reported symptoms of decompensated HF were less likely to receive effective cardiac treatments and had worse short‐term outcomes. Reasons for these differences in treatment practices and short‐term outcomes need to be elucidated and attention directed to these high‐risk patients. Copyright © 2010 Wiley Periodicals, Inc.
Subocclusion of the Sinus Node Artery During Coronary Angioplasty: Arrhythmological Considerations
Authors: D'Ascenzi Flavio , Iadanza Alessandro , Zacà Valerio , Pierli Carlo , Mondillo Sergio
Published: May 2010

We report the case of a 58‐year‐old man who developed atrial fibrillation as a result of iatrogenic subocclusion of a diseased sinus node artery, originating from the left circumflex artery (LCx), occurring during LCx stenting, suggestive of an ischemic etiology of sinus node dysfunction. Copyright © 2010 Wiley Periodicals, Inc.
Sinus Arrest due to Sertraline
Authors: Kocabay Gonenc , Yildiz Mustafa , Eksi Duran Nilufer , Ozkan Mehmet
Published: May 2010

Sertraline is a selective serotonin reuptake inhibitor with established safety for the treatment of depression. Among the common adverse effects associated with sertraline are nausea, insomnia, diarrhea, somnolence, and dizziness. Cardiac arrest had not been reported in the literature, although tachycardia was frequently seen. In this case report, a patient was presented who had adverse reactions such as nausea, dizziness, insomnia under citalopram treatment, and after his drug was changed to sertraline, developed sinus arrest on the fourth day of treatment. Copyright © 2010 Wiley Periodicals, Inc.
Improving Myocardial Perfusion by Percutaneous Coronary Intervention Reduces Central Sympathetic Activity in Stable Angina
Authors: Gomes Marc E. , Aengevaeren Wim R. , Lenders Jacques W. , Verheugt Freek W. , Smits Paul , Tack Cees J.
Published: May 2010

Background

By stimulating sympathetic afferents, repetitive myocardial ischemia induces a state of increased sympathetic tone.

Hypothesis

Removing the ischemic trigger by revascularization using percutaneous coronary intervention (PCI) might thus reduce central sympathetic activity in symptomatically stable angina patients.

Methods

A total of 20 patients with stable angina ≥ New York Heart Association (NYHA) class II with persistent symptoms despite maximal pharmacological therapy and a clinical indication for PCI, were included in our study. Sympathetic nervous system activity was measured before and 1 month after PCI by a combination of techniques: direct muscle sympathetic nerve activity (MSNA), neurochemical (plasma catecholamine levels), and heart rate variability (HRV).

Results

All patients completed the study. After PCI there was a significant reduction in MSNA (pre‐PCI 72 ± 4 to post‐PCI 53 ± 4 burst/100 beats, P < .05) and low frequency/high frequency (LF/HF) ratio (3.7 ± 0.6 vs 2.4 ± 0.4, P < .05) consistent with a decline in sympathetic activity. Plasma norepinephrine levels were reduced after PCI, but this difference did not reach statistical significance (1.84 ± 0.17 vs 1.73 ± 0.13 nmol/L, P = not significant).

Conclusion

Coronary revascularization by PCI reduces sympathetic activity in patients with established myocardial ischemia. Copyright © 2010 Wiley Periodicals, Inc.
Prolonged Postsurgical Survival Without a Pulmonic Valve: Case Report and Review of the Literature
Authors: Te Charles C. , Bauer Christopher E. , Abu‐Fadel Mazen S. , Peyton Marvin , Sivaram C.A.
Published: May 2010

Pulmonic valve stenosis is usually congenital and causes right‐sided heart failure secondary to pressure overload. We report the case of a 56‐year‐old male with congenital pulmonary valve stenosis who presented with severe right heart failure 32 years after pulmonary valvectomy. He subsequently underwent pulmonary valve replacement and did well. Pulmonary valvectomy is an uncommon treatment for pulmonary stenosis and this is the longest documented survival of a patient without a pulmonic valve. Copyright © 2010 Wiley Periodicals, Inc.
Apolipoprotein E Polymorphism and the Characteristics of Diseased Vessels in Male Chinese Patients With Angiographic Coronary Artery Disease: A Case‐Case Study
Authors: Li Shao‐Sheng , Yang Jie , Li Lan‐Sun , Wang Hai‐Chang
Published: May 2010

Background

Variations in the apolipoprotein E (apo E) gene may predict the incidence of coronary artery disease (CAD). However, the correlation between apo E polymorphism and the severity of CAD is still unclear.

Hypothesis

Apolipoprotein E polymorphism can predict CAD.

Methods

Used a case‐case study of 213 Chinese angiographically‐defined CAD patients who were screened for apo E genotypes. The characteristics of their diseased vessels were recorded.

Results

Apolipoprotein E4 carriers had > 75% stenosis, more wide‐ranging and longer vessel disease, a greater number of diseased vessels, and a higher Gensini score than apo E2 carriers or individuals with the apo E3/3 genotype. Apolipoprotein E2 carriers had ≤75% stenosis and a shorter length of vessel disease than individuals with the apo E3/3 genotype or apo E4 carriers. The severity of stenosis, length of vessel disease, and number of diseased vessels were affected by the interaction between genotype and body mass index, family history of CAD, total plasma cholesterol level, smoking history, and hypertension history.

Conclusion

The apo E4 allele may serve as an independent genetic marker predicting severity of CAD. Other CAD risk factors may accelerate the process of pathogenesis. The apo E2 allele may play a protective role. Copyright © 2010 Wiley Periodicals, Inc.
Comparison of Traditional Risk Factors, Angiographic Findings, and In‐Hospital Mortality between Smoking and Nonsmoking Turkish Men and Women With Acute Myocardial Infarction
Authors: Aygul Nazif , Ozdemir Kurtulus , Abaci Adnan , Aygul Meryem Ulku , Duzenli Mehmet Akif , Yazici Huseyin Ugur , Ozdogru Ibrahim , Karakaya Ekrem
Published: May 2010

Background

The prevalence of smoking is high in Turkey. However, there are no data available evaluating the differences between smokers and nonsmokers according to their sex in patients with acute myocardial infarction (AMI) in Turkey.

Hypothesis

The aim of the study was to determine the prevalence of smoking and its relationship to age, localization, and extension of coronary heart disease (CHD), and other risk factors in Turkish men and women with first AMI.

Methods

This study included, 1502 patients with first AMI from 3 different cities in Turkey. The baseline characteristics and traditional risk factors for CHD, Coronary angiographic results, and in‐hospital outcome were recorded.

Results

The proportion of male smokers was significantly higher than that of women (68% vs 18%, P < 0.001). Smokers were younger by almost a decade than nonsmokers (P < 0.001). Male nonsmokers were younger than females; however, the mean age of first AMI was similar in male and female smokers. In both genders, prevalence of hypertension and diabetes mellitus was significantly lower in smokers than in nonsmokers (P < 0.001). Smokers had less multivessel disease and less comorbidity as compared to nonsmokers. Although the in‐hospital mortality rate was lower in smokers, smoking status was not an independent predictor of mortality.

Conclusions

Smoking, by decreasing the age of first AMI in women, offsets the age difference in first AMI between men and women. The mean age of first AMI is lower in Turkey than most European countries due to a high percentage of smoking. Copyright © 2010 Wiley Periodicals, Inc.
Mechanism and Clinical Significance of the Prothrombotic State in Patients With Essential Hypertension
Authors: Yang Ping , Liu Ya‐Fen , Yang Li , Wei Qun , Zeng Hong
Published: May 2010

Background

Thrombotic, rather than hemorrhagic, events represent a major complication of hypertension. This study aims to explore the mechanism of the hypercoagulative state in hypertension and to assess its clinical significance.

Hypothesis

The hypercoagulative state and even the prothrombotic state exists in patients with hypertension. This may be attributed to an impairment of the endothelium.

Methods

A total of 81 patients suffering from essential hypertension were classified into 3 groups (grade 1: n = 27; grade 2: n = 36; grade 3: n = 18) and an additional 28 nonhypertensive patients were used as the control group. This study determined the changes of platelet activation marker P‐selectin (CD62P), plasma fibrinogen, plasminogen activitor inhibitor‐1 (PAI‐1), and endothelium function.

Results

The percentage of CD62P+ platelets and the concentration of plasma fibrinogen and PAI‐1 in the hypertension group was significantly higher than those in the control group. These increments coincided with the elevation of blood pressure. A significant difference was found between any of the 2 hypertension subgroups in the percentages of CD62P+ platelets (P < 0.001) and the concentration of PAI‐I (P < 0.05). No difference was noted between the hypertension grade 1 and 2 groups in the concentration of plasma fibrinogen (P = 0.079); however, a significant difference was found between any of the other 2 subgroups (P < 0.001). Flow‐mediated dilation (FMD) in the hypertension group was significantly lower than that in the control group.

Conclusions

The hypercoagulative state exists in patients with hypertension and this state was more obvious with the elevation of blood pressure and coincided with an impairment in the degree of endothelium‐dependent vasodilation. Copyright © 2010 Wiley Periodicals, Inc.
Clinostatic Hypertension and Orthostatic Hypotension
Authors: Lagi Alfonso , Spini Simona
Published: May 2010

Background

The association of clinostatic hypertension (CH) and orthostatic hypotension (OH) is described as the “Hyp‐Hyp phenomenon,” and it has been found in about 5.5% of hypertensive patients and in up to 50% of patients with OH. The importance of CH/OH in clinical practice is mainly due to the presence of troublesome symptoms, end‐organ damage, and difficulties in its clinical management.

Hypothesis

The review focuses on the clinical problem of CH and review the international literature for the best management, including the diagnostic work‐up and the taylored treatment for this kind of patients.

Methods

A systematic review of the literature was conducted through MEDLINE research to focus the main controversial issues about CH/OH. Included topics: (1) the diagnostic work‐up, (2) the association with dysautonomic failure and syncope, and (3) the treatment options and prevention of end‐organ damage.

Results

Current standard reference for OH diagnosis includes functional assessment of the cardiac vagal nervous system and the sympathetic adrenergic system. The association with dysautonomic failure and with syncope needs further investigation. Pharmacologic treatment of OH is aimed at controlling symptoms rather than restoring normotension. Midodrine is the only medication that has been put to multicenter placebo‐controlled trial and subsequently approved by the U.S. Food and Drug Administration (FDA) for OH treatment. Short‐acting oral antihypertensive agents at bedtime should be considered in patients with severe, sustained CH.

Conclusions

Data obtained from the literature review showed that clinical diagnosis of the Hyp‐Hyp phenomenon is relatively simple, but it remains more difficult to establish the causal disease. In our opinion, it is advisable to define simple diagnostic standards for the selection of patients at risk of dysautonomic impairment so that a subsequent highly specific diagnostic work‐up could be initiated. Copyright © 2010 Wiley Periodicals, Inc.