bluuebunny/crossref_metadata_2025 huggingface dataset:
Complications associated with left ventricular puncture
Authors: Pitta Sridevi R. , Cabalka Allison K. , Rihal Charanjit S.
Published: October 2010

Objective: To report complications in a consecutive series of patients undergoing percutaneous left ventricular apical puncture (LVAP) and sheath placement for diagnostic or interventional procedures. Background: Percutaneous LVAP is only rarely used to provide hemodynamic data in the presence of mechanical prosthetic valves. Recently, LVAP has been used to facilitate complex interventional procedures such as paravalvular leak closures. These frequently necessitate placement of 4–6 F sheaths, rather than smaller needles. Optimal technique and outcomes are largely unknown for this uncommon procedure. Methods: We retrospectively analyzed 32 patients undergoing LVAP with echocardiographic and fluoroscopic guidance at our institution between 2002 and 2009. These patients were referred to the cardiac catheterization laboratory for hemodynamic assessment to rule out prosthetic dysfunction and or to facilitate paravalvular leak closure. Sheaths ranged from 4 to 6 F were removed at the end of the procedure after reversing any anticoagulation. No specific closure devices were used for hemostasis. Frequency of access site complications associated with LVAP recorded. Results: Apical access site related complications were higher in patients requiring LVAP for intervention than for diagnostic purposes (25% vs. 12.5%). Hemothorax was the most frequent serious complication occurring in 6 (19%) patients and frequently required intervention 5(16%). Three patients had local bleeding with no drop in hemoglobin or need for intervention. Conclusions: LVAP is associated with a significant incidence of access‐related complications. There is a need for safe and reliable methods of closing percutaneous LVAP access sites. © 2010 Wiley‐Liss, Inc.
Transcatheter closure of perimembranous ventricular septal defect in children: Safety and efficiency with symmetric and asymmetric occluders
Authors: Yang Rong , Sheng Yanhui , Cao Kejiang , Kong Xiangqing , Xu Di , Yong Yonghong , Zhou Lei , Zhang Hao , Qian Linmei , Sun Wei , Gu Zhengnan
Published: October 2010

Objectives: This study was designed to determine the safety and efficiency of asymmetric and symmetric ventricular septal occluders (AVSDOs and SVSDOs, respectively) for closure perimembranous ventricular septal defect (PMVSD) in children. Methods: Between January 2003 and December 2007, 142 children with PMVSD were treated with occluders (64 with AVSDOs and 78 with SVSDOs). Results: The defect diameter was 5.3 ± 1.1 mm in the AVSDO group and 5.4 ± 1.3 mm in the SVSDO group (P > 0.05). The success rates were similar between two groups [93.8% (AVSDO) vs. 94.9% (SVSDO), P > 0.05]. Two patients in the AVSDO group were switched to the SVSDO group due to residual shunts, and one patient in the SVSDO group was switched due to aortic regurgitation after deployment of the occluder. After procedure, 17 patients [seven with AVSDOs and nine with SVSDOs (P > 0.05)] developed various types of heart block (HB). Among them, 13 patients converted to the normal sinus rhythm. The remaining four cases had not recovered at the end of the study. Conclusions: Transcatheter closure of PMVSD using both AVSDO and SVSDO was safe and effective. Development of HB was the main complication for both devices. © 2010 Wiley‐Liss, Inc.
A Switch‐On Fluorescence Assay for Bacterial β‐Lactamases with Amyloid Fibrils as Fluorescence Enhancer and Visual Tool
Authors: Zou Lan , Cheong Wing‐Lam , Chung Wai‐Hong , Leung Yun‐Chung , Wong Kwok‐Yin , Wong Man‐Kin , Chan Pak‐Ho
Published: October 2010

Herein is described the development of a novel switch‐on fluorescence assay for detecting β‐lactamases. The fluorescence assay comprises two components: solid beads coated with a β‐lactam antibiotic, which is linked to an environment‐sensitive fluorophore (dansylaminothiophenol, DTA), and amyloid fibrils of hen lysozyme (acting as fluorescence enhancer and visual tool). In the presence of the clinically significant TEM‐1 β‐lactamase, the DTA–antibiotic complex on the solid beads is hydrolyzed, thus releasing the DTA dye into solution. The DTA dye is only weakly fluorescent in solution but gives strong green fluorescence upon binding to lysozyme fibrils. These strongly fluorescent DTA‐bound fibrils can be easily visualized by the naked eye upon illumination of the sample with a simple UV lamp. The fluorescence assay can detect TEM‐1 at low concentration (0.01 nM). In contrast, no observable fluorescence appears when the fluorescence assay is performed on samples without the TEM‐1 β‐lactamase.
Theoretical elucidation on the functional role of pyrrolidine‐type ionic liquids in inducing stereoselectivity of the Michael addition of cyclohexanone with trans‐β‐nitrostyrene
Authors: Sun Hui , Zhang Dongju
Published: October 2010

Density functional theory calculations have been carried out to elucidate the stereoselectivity of the Michael addition of cyclohexanone with trans‐β‐nitrostyrene, induced by a chiral ionic liquid (CIL) pyrrolidine‐imidazolium bromide. By comparison of the CC bond forming processes in the absence and presence of Br− anion, we found that intermolecular H‐bonds between the imidazolium cation and the nitro group of trans‐β‐nitrostyrene and the steric hindrance of the imidazolium cation moiety on the Si‐face of enamine dominate the stereoselectivity of the Michael addition. The presence of Br− anion obviously reduces the barrier by increasing the polarity of the C4C5 bond of enamine. The theoretical results rationalize well the early experimental finding, and reveal a valuable clue for the further CIL design with high catalytic efficiency. Chirality, 2011. © 2010 Wiley‐Liss, Inc.
Optical activity and Alfred Werner's coordination chemistry
Authors: Ernst Karl‐Heinz , Berke Heinz
Published: October 2010

It is widely accepted, that Pasteur's seminal discovery of the opposite optical activity of ammonium sodium tartrate enantiomorphs in solution gave the spark to organic stereochemistry and led to the development of the tetrahedron model by van't Hoff and Le Bel. The proof that chirality is inherently connected to octahedral coordination chemistry fostered greatly Werner's spatial views of metal complexes and his coordination theory. The actual proof of principle was established via separation of diastereomeric camphor sulfonate salts of racemic metal complexes. Chirality, 2011. © 2010 Wiley‐Liss, Inc.
Enantiomer self‐disproportionation and chiral stationary phase based selective chiral separation of organic compounds
Authors: Mayani Vishal J. , Abdi Sayed H. R. , Mayani Suranjana V. , Kim Heon‐Chang , Park Seung‐Kyu
Published: October 2010

In modern chromatography, chiral stationary phase (CSP) and enantiomer self‐disproportionation (ESD) are new inventions of packing material offer a guarantee for a successful enantiomeric separation. All CSPs were synthesized by chemical bonding of the relevant organic moieties onto a porous parent silica material for the separation of various racemic mixtures whereas achiral silica matrix was used for separation of non‐racemic mixtures in ESD. Our present study provides to establish an understanding on the entire enantio‐selective profile of amino alcohol based CSP as well as ESD and their precise utilization for high success ratesfor selective enantiomer separation with its appropriateness. Chirality, 2011. © 2010 Wiley‐Liss, Inc.
Das Gesetz vom Minimum. Liebig oder Sprengel?
Authors: Gröger Martin
Published: October 2010

Zu Beginn des 19. Jahrhunderts vollzog sich langsam der Wandel von der Humustheorie zur Mineralstofflehre. Carl Sprengel kann als Wegbereiter der neuen Lehre angesehen werden, deren Grundlagen er als erster klar formulierte. Doch erst Justus von Liebig verhalf der Mineralstofflehre zum Durchbruch. So hat Sprengel auch bereits 1828 das Gesetz vom Minimum formuliert, welches heute noch häufig dem populäreren Liebig zugeschrieben wird. Die bekannte Analogie zur Visualisierung des Gesetzes als Minimum‐Tonne geht auf keinen der beiden Protagonisten zurück. Diese Analogie hat sich seit 1903 behauptet, obwohl es bereits 1910 einen Wettbewerb zur Entwicklung einer besseren Darstellung gab.
Die Quadratur des Kohlenstoffs
Authors: Groß Michael
Published: October 2010

Ist Cyclobutadien quadratisch oder rechteckig? Mehrere Jahrzehnte nach der ersten Synthese des anti‐aromatischen, extrem instabilen Rings aus vier Kohlenstoffatomen hat eine Kristallstrukturanalyse des Moleküls in einem eigens entworfenen Käfig diese Frage auf überraschende Weise beantwortet.
Studies of Anti‐HIV Transcription Inhibitor Quinolones: Identification of Potent N1‐Vinyl Derivatives
Authors: Tabarrini Oriana , Massari Serena , Daelemans Dirk , Meschini Francesco , Manfroni Giuseppe , Bottega Laura , Gatto Barbara , Palumbo Manlio , Pannecouque Christophe , Cecchetti Violetta
Published: October 2010

The 6‐desfluoroquinolones (6‐DFQs) are anti‐HIV agents that target Tat‐mediated transcription. This particular mechanism of action makes this class of compounds very attractive for further structural investigations. Identification of the pharmacophore required for inhibition will ultimately result in the design of more selective analogues for use in combination therapy for the treatment of HIV infections. We have focused on the pyridone ring of the quinolone nucleus present in these compounds, designing new modifications to broaden the structure–activity relationship knowledge base. Herein, we present novel and very potent anti‐HIV quinolones, most notably those bearing an amino or vinyl group at the N1 position. Attempts were made to determine the structural parameters necessary to impart potent anti‐HIV activity to the vinyl derivatives.
Defeating Radiation Damping and Magnetic Field Inhomogeneity with Spatially Encoded Noise
Authors: Michal Carl A.
Published: October 2010

A simple NMR experiment capable of providing well resolved spectra under conditions where either radiation damping or static magnetic field inhomogeneity would broaden otherwise high‐resolution NMR spectra is introduced. The approach involves using a strong pulsed magnetic field gradient and a selective radio‐frequency pulse to encode a predetermined noise pattern into the spatial distribution of magnetization. Following readout in a much smaller field gradient, the noise sequence may be deconvolved from the acquired data and a high‐resolution spectrum is obtained, eliminating the effects of either radiation damping or the static field inhomogeneity. In the presence of field inhomogeneity a field map is also obtained from the same single transient. A quasi‐two‐dimensional version of the experiment eliminates the need for deconvolution and produces improved results with simplified processing, but without requiring a full two‐dimensional experiment. Example spectra are shown for both radiation damping and one‐dimensional field inhomogeneity with improvement in linewidths of more than a factor of 40.
Informed trading around merger and acquisition announcements: Evidence from the UK equity and options markets
Authors: Spyrou Spyros , Tsekrekos Andrianos , Siougle Georgia
Published: October 2010

This paper offers new evidence on informed trading around merger and acquisition announcements from the UK equity and options market. The analysis suggests that in about 25–33% of events there is abnormal option trading volume during the month that precedes the announcement. Such evidence is found in both call and put option volumes, is robust to different “estimation” and “event window” lengths, to different sub‐samples, and to liquidity considerations. These results support the argument that informed investors will transact in both the options and the stock market, and are comparable to results reported by the FSA in the cash market. © 2010 Wiley Periodicals, Inc. Jrl Fut Mark 31:703–726, 2011
Apoptotic cells attenuate fulminant hepatitis by priming Kupffer cells to produce interleukin-10 through membrane-bound TGF-β
Authors: Zhang Minggang , Xu Sheng , Han Yanmei , Cao Xuetao
Published: October 2010

The liver, a unique tolerogenic organ, is regarded as the site to trap and destroy aging erythrocytes and activated T cells. However, to date, the mechanisms for why the liver is tolerogenic and whether liver Kupffer cells (KC) are critical phagocytes for apoptotic cells (AC) contributing to the liver immunosuppression remain unclear. Here we report that KC is the main phagocyte for AC in the liver. Contact of AC inhibits proinflammatory cytokine but enhances anti-inflammatory cytokine production of KC in response to lipopolysaccharide (LPS) stimulation. Membrane-bound transforming growth factor (TGF)-β on AC is responsible for the increased production of interleukin (IL)-10 in KC through extracellular signal-regulated kinase (ERK) activation via the Smad3 pathway. Importantly, KC-derived IL-10 is critical for AC infusion-mediated protection of endotoxin-induced fulminant hepatitis through suppression of tumor necrosis factor (TNF)-α and nitric oxide (NO) production from KC and consequently attenuation of KC-mediated cytolysis of hepatocytes.

Conclusion:

AC can be preferentially phagocytosed by KC in the liver, leading to attenuation of fulminant hepatitis through IL-10-mediated suppression of KC-derived inflammatory TNF-α and NO production. These findings demonstrate that priming of KC by AC may contribute to maintain liver immunosuppression, providing a new mechanistic explanation for how immune homeostasis is maintained in the liver. (Hepatology 2011.)
Estradiol promotes spine growth and synapse formation without affecting pre‐established networks
Authors: Mendez Pablo , Garcia‐Segura Luis Miguel , Muller Dominique
Published: October 2010

Estrogens regulate dendritic spine density, but the mechanism and significance of this effect for brain networks remain unknown. We used repetitive imaging over several days to investigate how 17β‐estradiol affected the turnover and long‐term behavior of dendritic spines in CA1 cells of hippocampal slice cultures. We find that 17β‐estradiol and serum in the culture medium tightly regulated spine density by promoting an increase in the rate of new spine formation and their transformation into synapses, without affecting spine elimination or stability. New spines formed during a transient 17β‐estradiol application were preferentially eliminated upon removal of the hormone, in contrast with pre‐existing spines that remained unaffected. Our results reveal that 17β‐estradiol transiently regulates the complexity of hippocampal circuits without causing major alterations of pre‐existing networks. © 2010 Wiley Periodicals, Inc.
Evaluating community participation as prevention: life narratives of youth
Authors: Janzen Rich , Mark Pancer S. , Nelson Geoffrey , Loomis Colleen , Hasford Julian
Published: October 2010

Community‐based prevention programs strive to foster the composition of positive life stories, in part, by promoting active participation in community settings. This article used life narratives of youth to explore the experience of community participation and showed how such participation influenced their lives. Youth aged 18–19 years who participated in Better Beginning, Better Futures (n=62), a community‐based prevention program, when they were aged 4–8 years, recounted stories of their lives that showed significantly higher levels of participation in community programs and greater personal impacts of that involvement compared with youth who were not involved in Better Beginnings (n=34). Qualitative analysis of a subsample of these youth (n=34) revealed individual and community characteristics that were instrumental in fostering positive outcomes of community participation. The findings indicated both the utility of using a narrative approach to evaluate community‐based prevention programs and the value of community participation for children and youth. © 2010 Wiley Periodicals, Inc.
Cross‐sectional and longitudinal effects of sixth‐grade setting‐level norms for nonviolent problem solving on aggression and associated attitudes
Authors: Henry David , Chan Wing Yi
Published: October 2010

Setting‐level norms are typically measured by using the mean of individual reports. Investigating norms for nonviolent problem solving, this study assessed the added value of two additional characteristics: the range of acceptable behaviors and the degree of consensus among individuals in each setting. Using data from 5,386 participants in a violence prevention project (74 classes), this study estimated the cross‐sectional and longitudinal effects of norm characteristics on aggression, beliefs about aggression, self‐efficacy for nonviolence, and beliefs about nonviolence. Each norm measure showed acceptable setting‐level reliability. Class mean approval predicted beliefs about aggression, self‐efficacy, and beliefs about nonviolence. With class means already in the model, the range of acceptable behaviors predicted additional cross‐sectional variance in all four outcomes. Consensus predicted aggression and beliefs about nonviolence beyond other characteristics. Mean approval and consensus had effects on growth in at least one outcome. Discussion focuses on the importance of setting‐level measurement and implications for intervention. © 2010 Wiley Periodicals, Inc.
Psychiatric morbidity and social capital in rural communities of the Greek North Aegean islands
Authors: Tseloni Andromachi , Zissi Anastasia , Skapinakis Petros
Published: October 2010

Which facets of social capital affect mental health in rural settings? This study explores the association between different aspects of social capital and psychiatric morbidity in rural communities of the Greek North Aegean islands. A large number of individual and community characteristics that may influence psychiatric morbidity are concurrently examined in multilevel models to account for the clustering of individuals within rural settings. The current findings indicate that psychiatric morbidity is, to a large extent, clustered within rural communities. Individuals' perceived divisions in the community, i.e., political party preference, landholdings, low social support networks, and lack of perceived solidarity, are associated with psychiatric morbidity according to theoretical expectation. At the community level, this risk is lower in villages with over 250 residents, where there are youth clubs or a common threat, for instance, property crime. © 2010 Wiley Periodicals, Inc.
TCT‐DMSO/[bmim]BF4: A novel promoter system for the synthesis of 3,5‐diaryl‐1,2,4‐thiadiazoles at ambient temperature
Authors: Khosropour Ahmad R. , Noei Jalil
Published: October 2010

An efficient and practical procedure for direct synthesis of 3,5‐diaryl‐1,2,4‐thiadiazoles by thioamides with 2,4,6‐trichloro‐1,3,5‐triazine (TCT) and dimethylsulfoxide using 1‐butyl‐3‐methylimidazolium tetrafluoroborate as an eco‐friendly reaction medium under ambient temperature is described. This protocol can be considered as a new procedure for 3,5‐diaryl‐1,2,4‐thiadiazoles synthesis. J. Heterocyclic Chem., (2010).
Synthesis and antibacterial evaluations of new pyridazino[4,3‐e][1,3,4]oxadiazines
Authors: Bakavoli Mehdi , Rahimizadeh Mohammad , Shiri Ali , Eshghi Hossein , Pordeli Parvaneh , Pordel Mehdi , Nikpour Mohsen
Published: October 2010

Several derivatives of the new pyridazino[4,3‐e][1,3,4]oxadiazine ring system were prepared, and their antibacterial evaluations were performed on four different Gram‐negative and Gram‐positive bacteria. J. Heterocyclic Chem., (2010).
The Radziszewski oxidation of cycloalkylidene‐α‐(thiazol‐ 2‐yl)acetonitriles: A new approach toward spirooxiranes
Authors: Dotsenko Victor V. , Krivokolysko Sergey G. , Litvinov Victor P.
Published: October 2010

Upon treatment with H2O2/KOH in EtOH or with Na2CO3/H2O2 in acetone, cycloalkylidene‐α‐(4‐arylthiazol‐2‐yl)acetonitriles afforded 2‐(4‐arylthiazol‐2‐yl)‐1‐oxaspiro[2.5]octane‐2‐carboxamides and 2‐(4‐arylthiazol‐2‐yl)‐1‐oxaspiro[2.4]heptane‐2‐carboxamides in excellent yields (76–100%). J. Heterocyclic Chem., 2011.
An enzyme‐mimetic chemical conversion and biogenetic outline for chemical marker pterocarponoid oxygen heterocycles from Kudzu vine
Authors: Khan Riaz A.
Published: October 2010

An enzymatic chemical conversion of isoflavone and chemical marker oxygen‐heterocycles pterocarponoids are carried out in an analogy to major subcellular enzymatic conversions involved in the natural biogenetic pathway and microbial interaction steps for oxygen‐proliferated products obtained from bioactive fractions of widely occurring Kudzu plant, Pueraria tuberosa. An outline for biogenesis of major pterocarponoid constituents from principal biogenetic precursor, deoxytuberosin, is also proposed for P tuberosa. J. Heterocyclic Chem., (2010).
Sperm morphology in the Malagasy rodents (Muroidea: Nesomyinae)
Authors: Ding Xiaodan , Leigh C.M. , Goodman S.M. , Bedford J.M. , Carleton M.D. , Breed W.G.
Published: October 2010

The morphology of the spermatozoon of representative species of the subfamily Nesomyinae (Muroidea: Nesomyidae), a monophyletic group of rodents endemic to Madagascar, was examined by light and electron microscopy to determine the sperm head shape and tail length across the species. Marked interspecific differences were found to occur in both the form of the sperm head and length of the tail. The species that possess a sperm head with an apical hook, which largely contains acrosomal material, generally displayed longer sperm tails, and a species with a spatulate sperm head had the shortest tail. The association between sperm head shape and tail length mirrors that previously found in Eurasian and Australasian murine rodents. Thus, the repeated association between sperm head shape and tail length across these groups of muroid rodents clearly indicates a functional relationship between these two features. A comparison of sperm morphology of the nesomyines to that of related muroid rodents on the mainland of Africa suggests that the possession of an apical hook is the ancestral condition. J. Morphol., 2010. © 2010 Wiley‐Liss, Inc.
Babbling, vegetative function, and language development after cricotracheal resection in aphonic children
Authors: Bohm Lauren A. , Nelson Marc E. , Driver Lynn E. , Green Glenn E.
Published: October 2010

Objective:

To determine the importance of prelinguistic babbling by studying patterns of speech and language development after cricotracheal resection in aphonic children.

Study Design:

Retrospective review of seven previously aphonic children who underwent cricotracheal resection by our pediatric thoracic airway team. The analyzed variables include age, sex, comorbidity, grade of stenosis, length of resected trachea, and communication methods.

Methods:

Data regarding the children's pre‐ and postsurgical communication methods, along with their utilization of speech therapy services, were obtained via speech–language pathology evaluations, clinical observations, and a standardized telephone survey supplemented by parental documentation. Postsurgical voice quality was assessed using the Pediatric Voice Outcomes Survey.

Results:

All seven subjects underwent tracheostomy prior to 2 months of age when corrected for prematurity. The subjects remained aphonic for the entire duration of cannulation. Following cricotracheal resection, they experienced an initial delay in speech acquisition. Vegetative functions were the first laryngeal sounds to emerge. Initially, the children were only able to produce these sounds reflexively, but they subsequently gained voluntary control over these laryngeal functions. All subjects underwent an identifiable stage of canonical babbling that often occurred concomitantly with vocalizations. This was followed by the emergence of true speech.

Conclusions:

The initial delay in speech acquisition observed following decannulation, along with the presence of a postsurgical canonical stage in all study subjects, supports the hypothesis that babbling is necessary for speech and language development. Furthermore, the presence of babbling is universally evident regardless of the age at which speech develops. Finally, there is no demonstrable correlation between preoperative sign language and rate of speech development.
The effect of blood inflow and B1‐field inhomogeneity on measurement of the arterial input function in axial 3D spoiled gradient echo dynamic contrast‐enhanced MRI
Authors: Roberts Caleb , Little Ross , Watson Yvonne , Zhao Sha , Buckley David L. , Parker Geoff J. M.
Published: October 2010

A major potential confound in axial 3D dynamic contrast‐enhanced magnetic resonance imaging studies is the blood inflow effect; therefore, the choice of slice location for arterial input function measurement within the imaging volume must be considered carefully. The objective of this study was to use computer simulations, flow phantom, and in vivo studies to describe and understand the effect of blood inflow on the measurement of the arterial input function. All experiments were done at 1.5 T using a typical 3D dynamic contrast‐enhanced magnetic resonance imaging sequence, and arterial input functions were extracted for each slice in the imaging volume. We simulated a set of arterial input functions based on the same imaging parameters and accounted for blood inflow and radiofrequency field inhomogeneities. Measured arterial input functions along the vessel length from both in vivo and the flow phantom agreed with simulated arterial input functions and show large overestimations in the arterial input function in the first 30 mm of the vessel, whereas arterial input functions measured more centrally achieve accurate contrast agent concentrations. Use of inflow‐affected arterial input functions in tracer kinetic modeling shows potential errors of up to 80% in tissue microvascular parameters. These errors emphasize the importance of careful placement of the arterial input function definition location to avoid the effects of blood inflow. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
The contribution of chemical exchange to MRI frequency shifts in brain tissue
Authors: Shmueli Karin , Dodd Stephen J. , Li Tie‐Qiang , Duyn Jeff H.
Published: October 2010

Recent high‐field MRI studies based on resonance frequency contrast have revealed brain structure with unprecedented detail. Although subtle magnetic susceptibility variations caused by iron and myelin seem to be important to this contrast, recent research on protein solutions suggests that chemical exchange between water and macromolecular protons may contribute substantially to the observed gray‐white matter frequency contrast. To investigate this, we performed spectroscopic MRI experiments at 14 T on samples of fixed human visual cortex and fresh pig brain. To allow direct observation of any exchange‐induced frequency shifts, these samples were soaked in reference chemicals (TSP and dioxane) that are assumed not to be involved in exchange. For both fresh and fixed tissues and with both reference chemicals, substantial negative exchange‐induced gray‐white matter frequency contrast (–6.3 to –13.5 ppb) was found, whereas intracortical contrast was negligible. The sign of the gray‐white matter exchange‐induced frequency difference was opposite to the overall gray‐white matter frequency difference observed in vivo. This suggests that exchange contributes to, but is not sufficient to explain, the frequency contrast in vivo and tissue susceptibility differences may have a greater contribution than previously thought. The exchange‐dependent contribution may report on tissue chemical composition and pH. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
High resolution three‐dimensional cardiac perfusion imaging using compartment‐based k‐t principal component analysis
Authors: Vitanis Viton , Manka Robert , Giese Daniel , Pedersen Henrik , Plein Sven , Boesiger Peter , Kozerke Sebastian
Published: October 2010

Three‐dimensional myocardial perfusion imaging requires significant acceleration of data acquisition to achieve whole‐heart coverage with adequate spatial and temporal resolution. The present article introduces a compartment‐based k‐t principal component analysis reconstruction approach, which permits three‐dimensional perfusion imaging at 10‐fold nominal acceleration. Using numerical simulations, it is shown that the compartment‐based method results in accurate representations of dynamic signal intensity changes with significant improvements of temporal fidelity in comparison to conventional k‐t principal component analysis reconstructions. Comparison of the two methods based on rest and stress three‐dimensional perfusion data acquired with 2.3 × 2.3 × 10 mm3 during a 225 msec acquisition window in patients confirms the findings and demonstrates the potential of compartment‐based k‐t principal component analysis for highly accelerated three‐dimensional perfusion imaging. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Acquired amyloid neuropathy in a Portuguese patient after domino liver transplantation
Authors: Conceição Isabel , Evangelista Teresinha , Castro José , Pereira Pedro , Silvestre Ana , Coutinho Conceição A , de Carvalho Mamede
Published: October 2010

Familial amyloid polyneuropathy (FAP) is a progressive neuropathy with autonomic dysfunction. Domino liver transplantation (DLT), in which the liver of an FAP patient is transplanted into another patient, is routinely applied to compensate for the shortage of available organs. We report a patient who developed a clinical picture of FAP 9 years after a DLT from an FAP donor. Electrophysiological, neuropathological, and autonomic tests were administered. The patient presented with typical clinical features of FAP. Electrophysiological investigation confirmed a moderate sensorimotor axonal and autonomic neuropathy. Sural nerve biopsy confirmed the presence of amyloid deposits in the endoneurium. Skin biopsy at the ankle showed reduced intraepidermal nerve fiber density. Our report shows that FAP can develop in a recipient of an FAP liver. This suggests that careful longitudinal study is required to evaluate the risk of FAP polyneuropathy in patients who undergo domino liver transplantation. Muscle Nerve, 2010
Solution of piecewise constant delay systems using hybrid of block‐pulse and Chebyshev polynomials
Authors: Marzban H. R. , Shahsiah M.
Published: October 2010

An efficient numerical method for finding the solution of piecewise constant delay systems is presented. The method is based upon hybrid of block‐pulse functions and Chebyshev polynomials. The operational matrix of delay is constructed. The properties of hybrid functions together with the operational matrices of integration, delay and product are used to convert the delay differential equation to an algebraic equation, thus greatly simplifying the problem. The method is easy to implement and yields very accurate results. The validity and applicability of the proposed method are demonstrated by considering different types of delay systems. Copyright © 2010 John Wiley & Sons, Ltd.
Haplo‐insufficiency: a driving force in cancer
Authors: Berger Alice H , Pandolfi Pier Paolo
Published: October 2010

It was originally proposed that tumour suppressor genes (TSGs) act in a recessive manner. Instead, numerous TSGs, including p53 and PTEN, exhibit haplo‐insufficiency as a consequence of the dose‐dependency of TSG function. Due to the challenges of identifying haplo‐insufficient TSGs by human genetics analysis alone, mouse models play a pivotal role in firmly establishing the haplo‐insufficiency of a gene, as in the recent identification of DOK2 as a haplo‐insufficient lung TSG. In many cases, TSGs exhibit conditional or compound haplo‐insufficiency, in which loss of one TSG allele is functionally important only in certain settings or after compound loss of other genes. The 5q deletion syndrome (5q−) is a paradigm of compound haplo‐insufficiency and demonstrates the importance of combinatorial interactions to elicit specific phenotypes. These concepts must be integrated into basic science studies to avoid delay in the identification of important TSGs. In the clinical realm, the challenges for molecular pathologists are the development of quantitative measures that can accurately and systematically ascertain the status of haplo‐insufficient genes in tumour biopsies, and the use of this information to accurately predict prognosis and response to therapy. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Drug consumption and air pollution: an overview
Authors: Menichini Federica , Mudu Pierpaolo
Published: October 2010

Purpose

Acute respiratory symptoms are among the health effects of air pollution exposure. Studies over the past decades have linked respiratory drug use (consumption or sales) with changes in air pollution conditions.

Methods

Twenty‐one studies were analyzed to discuss whether increased levels of air pollution are associated with the use of medications for respiratory diseases.

Results

Epidemiological studies agree that variation in the drug use is related to air pollution exposure. In panel studies, although asthmatics are more sensitive to air pollution effects, the increase in drug use was comparable and similar to non‐asthmatics. Ecological studies confirm a significant association in respiratory drug sales depending on the selected lags (that is the time elapsing between air pollution measurement and the resulting drug use). The results of a meta‐analysis of two ecological studies showed an increase in risk for increase in daily mean concentration of some pollutant (10 µg m−3). For Black Smoke RR = 1.007 (95% CI 1.004–1.011) for lag 1, and RR = 1.008 (95% CI 1.005–1.010) for lag 8. For Nitrogen dioxide, RR = 1.008 (95% CI 1.005–1.012) for lag 8 and for Sulfur dioxide, RR = 1.005 (95% CI 1.001–1.010) for lag 9.

Conclusions

The analysis of drug use provides useful data for the evaluation of risks which derive from exposure to air pollution. More studies are needed to measure the effects of air pollution on respiratory medication use. Lags of up to 14 days have to be considered and the pollutants to be considered should include particulate matter and ozone. Copyright © 2010 John Wiley & Sons, Ltd.
Theoretical investigation on chiral cinchona alkaloid salts‐catalyzed asymmetric epoxidation of cyclic enones
Authors: Lu Nan , Mi Shizhen , Chen Dezhan , Zhang Guiqiu
Published: October 2010

Chiral cinchona alkaloid salts‐catalyzed asymmetric epoxidation of 2‐cyclohexen‐1‐one with hydrogen peroxide (H2O2) has been investigated using density functional theory (DFT). The ring‐closure step is rate limiting in the catalytic reaction. The enantioselectivity‐determining step is initial nucleophilic addition involving two orientations of axial and equatorial. In (S)‐catalyst j‐mediated process, axial pathway is favored over equatorial leading to the major epoxide [2S,3S]‐3. An opposite enantiomer [2R,3R]‐3 is primarily generated in (R)‐catalyst k‐assisted case preferring equatorial pathway. The results indicate that the enantioselectivity of epoxidation is dominated by central chirality of the bifunctional catalysts in the activation of enone by primary amine salt via iminium formation and of H2O2 by tertiary amine reacting as a general base. The substituent effect is also discussed to clarify a tendency existing in experiment. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Determination of some descriptors of the real world working on the fundamental identity of the basic concept and the origin of the electronegativity and the global hardness of atoms. Part 2: Computation of the dipole moments of some heteronuclear diatomics
Authors: Ghosh Dulal C. , Islam Nazmul
Published: October 2010

To garner further support of our conjecture that “the electronegativity and the hardness manifest two different descriptors of the one and the same fundamental property of atoms,” we have derived a formula of evaluating the dipole charge of heteronuclear diatomic molecules, A–B, in terms of the global hardness of the atoms as: q = a (Δη/ηA) + b, where, a and b are two constants, q is the dipole charge, Δη is the hardness difference of the two atoms A and B, and ηA is the hardness of the harder atom. In deriving the above formula, we have relied upon the fact that hardness, similar to the electronegativity, controls the physical process of charge rearrangement during the chemical event of molecule formation. We have calculated the dipole charge and dipole moment of as many as 39 different types of compounds of widely divergent physico‐chemical behavior in terms of the algorithm derived in the present work. The computed dipole charge and dipole moment reveals the known chemico‐physical behavior of such compounds under study. A comparative study of the nature of variation of theoretically evaluated and experimentally determined dipole moments plotted in as many as six figures reveal that there is an excellent agreement between the two sets of dipole data. Hence, the ansatz suggested for the calculation of the dipole charge in terms of the hardness data of the atoms forming the compound is extremely efficacious in computing the charge distribution. It further transpires that the assumed model of charge rearrangement during the event of molecule formation is realistic and supports our basic conjecture that operationally the two descriptors, the hardness and the electronegativity, are identical. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
A novel 2D graphical representation of protein sequence based on individual amino acid
Authors: Yu Jia‐Feng , Sun Xiao , Wang Ji‐Hua
Published: October 2010

The primary structure, i.e., the amino acids sequence, plays determinant roles in dynamical folding process and stable structure of protein molecules, then how to put forward sequences based approaches to demonstrate the biological information of the primary sequence will facilitate correlative researches. In this article, we outline a novel 2D graphical representation on the basis of a selected pair of physiochemical properties of amino acids, which integrates both the electric and hydrophobic factors to demonstrate the characteristic features of proteins. This novel representation transforms protein into a zigzag curve uniquely and allows direct inspection of similarities/dissimilarities among different protein sequences with higher resolution than previous methods. From this representation, some efficient numerical descriptors are derived, by which we quantitatively analyze the evolutionary distances among the ND6 (NADH dehydrogenase subunit 6) protein sequences of eight species, the results are coincident with the actual evolutions, which illustrate the efficiencies of the present approach. This representation can also provide convenient tools and alternative studying strategies for protein sequences and structures analysis. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theoretical investigation on the mechanism and kinetics of OH radical with ethylbenzene
Authors: Huang Mingqiang , Wang Zhenya , Hao Liqing , Zhang Weijun
Published: October 2010

The OH hydrogen abstraction and addition with ethylbenzene have been studied in the range 298–1000 K using quantum chemistry methods. The geometries and frequencies of the reactants, transition states, and products were performed at BH and HLYP/6‐311++G(d,p) level, single point calculation for all the stationary points were carried out at CCSD(T) calculations of the optimized structures with the same basis set. Nine different reaction paths are considered corresponding to two side chain, three possible ring hydrogen abstraction, and four kinds different OH addition. The results of the theoretical study indicate that at the room temperature the reaction proceeds almost exclusively through OH addition, and is predicted to occur dominantly at the ortho position, the calculated overall rate constant is 6.72 × 10−12 cm3 molecule−1 s−1, showing a very good agreement with available experimental data. Although negligible at low temperature, at 1000 K ring hydrogen abstraction accounts for about 32% of the total abstraction reaction, and the whole hydrogen abstraction makes up for 30% of the total reaction. This study may provide useful information on understanding the mechanistic features of OH‐initiated oxidation of ethylbenzene. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Atomic term symbols via partitioning techniques
Authors: Olson John A.
Published: October 2010

Two techniques for obtaining Russell–Saunders term symbols (terms) for equivalent electrons is presented. Both techniques are based on partitioning the n equivalent electrons into a set of α electrons and a set of β electrons. Fundamental tables are presented that give the number of states for the α or β electrons for all possible values M(M) and Sα(Sβ). One interpretation of these tables leads to the total number of states of the n equivalent electrons for values of L and S. From this the number of terms for L and S is easily determined. Another interpretation of the fundamental tables gives the maximum number of terms for n equivalent electrons with values of L and S. From this the actual number of terms is obtained. Examples of equivalent p, d, f, and g electrons are provided. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theoretical study on the mechanisms of the nucleophilic substitution reactions of hydrosulfide ion and halomethanes
Authors: He Jianyong , Long Zhengwen , Jing Jian , Zhang Jin‐Sheng
Published: October 2010

Three species involved in the nucleophilic substitution reaction of hydrosulfide ion and halomethanes are investigated by ab initio calculations. Geometries for stationary structures along the reaction paths are fully performed with the second‐order Møller–Plesset perturbation approximation with the cc‐pVDZ basis set. The monomer geometries determined by the MP2 method match the experimental results very well. Single point energy calculations are carried out at the coupled cluster with perturbative triple excitations CCSD (T) theory with aug‐cc‐pVDZ basis set. Halomethanes have three conformers here, which lead to the three product channels, HSCH3+ F−1, HSCH3+ Cl−1, and HSCH3+ Br−1. The investigation encompasses the six complexes formed among three channels, respectively. By selecting the six complexes as the model, we investigate the binding energy, topological property of the electron charge density and their Laplacian in detail theoretically. Electrostatic density potential maps of halomethanes are generated for the determination of attractive interaction sites. It is proved that the similar misshaped electron clouds of the three halogen atoms result in the similar properties of the carbon‐halogen bonds, and reveals that the product ion‐dipole complexes interactions are predominantly electrostatic in nature. The calculated results predict the binding energy of the most stable complex in six complexes is −47.06 kcal/mol at the MP2 level of theory. The second channel has the lowest energy barrier, which is −3.63 kcal/mol at the CCSD (T) levels of theory, is expected to be the most important pathway. It occurs via CCl cleavage accompanied by CS bond formation. The other two channels have higher energy barriers and are expected to have smaller rates. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theoretical considerations on the hydrolysis of 2‐dichloromethylbenzimidazole
Authors: Pop Raluca , Medeleanu Mihai , Csunderlik Carol
Published: October 2010

Hydrolysis reaction of 2‐dichloromethylbenzimidazole with aqueous diethylamine was studied both experimentally and theoretically. The behavior of two other aromatic dihalides (dibromomethylbenzene and 2‐fluoro‐dichloromethylbenzene) was also theoretically studied, starting from already known experimental results. The theoretical calculations of local DFT‐based descriptors (i.e., Fukui function, electrophilicity index) successfully account for the different reactivity of the three aromatic dihalides in the same hydrolysis reaction. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Kinetic and thermodynamic study of inter‐ and intramolecular proton transfer in N′‐acetyl formohydrazide tautomers
Authors: Tavakol Hossein
Published: October 2010

Nine tautomers and eleven possible tautomeric interconversions of N′‐acetyl formohydrazide have been studied at B3LYP/6‐311++G** level of theory. From these calculations, optimized geometries, molecular parameters, IR frequencies, NMR chemical shifts, and energetic results are obtained. In all tautomers except tautomers 4, E isomer is more stable than Z isomer. Energetic data were used to calculate the energy barriers of tautomeric interconversions and very high energy barriers were obtained for all tautomeric interconversions. Moreover, study of solvent effects on relative stabilities of tautomers and transition states showed that they are similar to those in the gas phase. In addition, intermolecular proton transfer with the assistance of one to three water molecules has been studied and the results showed that activation barriers in water‐assisted tautomerism are in general lower than those in the gas phase. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Calculations of the infrared and Raman spectra of simple thiols and thiol–water complexes
Authors: Kieninger Martina , Ventura Oscar N.
Published: October 2010

The frequencies and intensities of infrared and Raman spectra of H2S, CH3SH, CH3CH2SH, and CH2CHCH2SH, isolated and complexed with one water molecule acting as a proton acceptor were calculated at the ab initio and density functional level. Hartree‐Fock, MP2 and CCSD(T) methods were used both for the geometry optimization and spectra calculations at the molecular orbital level. The B3LYP, PBE0, and M06 exchange‐correlation potentials were employed to calculate the same properties at the DFT level. Both Pople basis sets, 6‐31+G(d) and 6‐311++G(3df,2pd), and Dunning basis sets, aug‐cc‐pVTZ and aug‐cc‐pVQZ, were used. SH and CS frequency shifts upon water complexation were studied, and a discussion is performed on the expected relation between the CH and CS Raman activities, in view of their usefulness for studies in protein chemistry. Scaling factors for the vibrational frequencies were obtained for all the combination of methods and basis sets, and shown to be completely similar to the ones present in the literature when available. Scaling factors for the M06 method are presented for the first time with these basis sets. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
A network selection scheme for multicast applications in wireless network convergence
Authors: Kim Jaecheol , Lee Ji Hoon , Lee Hojin , Kwon Taekyoung , Choi Yanghee
Published: October 2010

In wireless network convergence, each mobile host is expected to have multiple kinds of wireless interfaces. Multicast‐based applications are expected to be widely deployed. In this paper, a new network selection scheme is proposed for a mobile host to select the most appropriate wireless access network to maximize user satisfaction and ISP's profit, simultaneously. We have devised a metric to measure a user's satisfaction and we also developed a ‘normalized network resource’ metric for system profit measure. We have compared our scheme with three other reference schemes, through simulations. Depending on the network deployment situations, our scheme exhibits one‐fifth service disruption time of other reference schemes, while the resource consumption of our scheme is comparable to that of the minimum resource scheme. Overall, the gain of our scheme becomes higher as users move faster and/or the population density increases. Copyright © 2010 John Wiley & Sons, Ltd.