bluuebunny/crossref_metadata_2025 huggingface dataset:
Results of Rock-Eval/Toc Analysis of Core Through the Lower Cretaceous: Monkman Pass area, northeastern British Columbia
Authors: Leckie D A
Published: November 2010

Shale and coals from 1.2 km of core through most of the Lower Cretaceous preserved in Western Canada were analyzed for source rock potential and maturation levels. The Minnes Group, averaging 2.7% TOC, has some potential for gas generation from a limited
number of samples. The Gething and Gates formations average 6.3 and 5.2% TOC, respectively, and some samples show potential for gas. The marine Moosebar and Hulcross formations have 1.5 and 1.7% TOC, respectively, and very low hydrocarbon yields on pyrolysis. These marine sediments contain
dominantly Type III organic matter (OM) with lesser amounts of thermally degraded Type II. The Boulder Creek Formation has 1.1 % TOC and poor source rock potential. Most Boulder Creek OM was oxidized during Late Albian sea level fluctuation when thick paleosols developed. Hydrogen Index (HI) for
the marine sediments show a progressive decrease with depth from 132 to 61 mg HC/ g of TOC interpreted as due to thermal degradation of Type II OM with increased burial. These marine sediments may have generated limited amounts of oil. HI for nonmarine sediments is scattered with no apparent trend
with depth. Tmax values are consistently lower for the marine samples of the Shaftesbury and Moose bar formations than adjacent nonmarine samples and for the upper portion of the Minnes Group. Despite a fairly large scatter, the vitrinite reflectances increase systematically with stratigraphic
depths from 0.94% R0max at the top of the Boulder Creek Formation to 1.5% R0max in the Minnes Group. The reflectances indicate high volatile A bituminous and medium/low volatile bituminous coals. From the coalification gradient (0.05% R0max/100m depth), the end of oil generation for
potential source rocks is indicated at the base of the Gething Formation.
Stratigraphy and structure of the St. Lawrence Lowland in the Charlevoix area, Quebec: relationships to impact cratering
Authors: Lemieux Y , Tremblay A , Lavoie D
Published: November 2010

The Charlevoix area, located 100 km northeast of Quebec City, was the site of a meteoritic impact some 350 million years ago. Few studies have documented the tectonic event sequence of this area before and after the impact. Some field observations suggest that
the actual fault systems in the Charlevoix area could have been induced during the rifting of the Iapetan Ocean during Late Proterozoic and Early Cambrian. In addition, those faults could have been reactivated during the meteorite impact and even in Mesozoic time due to rifting of the Atlantic
Ocean. However, relationships between the inferred impact cratering with structures left by the Iapetan rifting and/or Mesozoic reactivation have still to be documented.
A combined fluid-inclusion and stable isotope study of Ordovician ophicalcite units from southern Quebec Appalachians, Quebec
Authors: Chi G , Lavoie D
Published: November 2010

This paper reports on microthermometric data of fluid inclusions from calcite cements in ophicalcite units from the Rivière des Plantes ophiolitic mélange, and integrates them with previously published stable isotope data to estimate the isotopic
composition of the parent fluids. Potential primary fluid inclusions may be either monophase (liquid) or biphase (liquid+vapor). The biphase fluid inclusions show an overall range of homogenization temperatures (Th) from 85°C to 173°C, and final ice-melting temperature (Tm-ice) from
-6.6°C to -2.3°C. The monophase fluid inclusions show Tm-ice values similar to those of the biphase fluid inclusions, and possibly have been entrapped at temperatures around or lower than 50°C. The d18O values of the parent fluids are estimated to be 1.9 o/oo to +4.9 o/oo SMOW if
the biphase inclusions are primary, and 7.8 o/oo to 6.6 o/oo SMOW or lower if the monophase fluid inclusions are primary.
Analyse structurale et tectonique de la Plate-forme du Saint-Laurent (Québec, Canada) : résultats préliminaires
Authors: Rocher M , Tremblay A , Nadeau L , Lavoie D
Published: November 2010

The Cambrian-early Ordovician St. Lawrence Platform represents the eastern passive margin of the Iapetus Ocean and is partly covered by Ordovician sedimentary rocks of the Appalachian foreland basin. A study is underway to reconstruct the tectonic and structural
history of the platform in the St. Lawrence Lowlands area. Field data were used for paleostress analyses. A major northwest-southeast extension, which caused normal movement along northeast-trending faults bordering the region to the north, is attributed to the collapse of the margin, but
apparently continued during and after the Appalachian collision. This collision is recorded locally in the St. Lawrence Lowlands as structures indicating west-northwest-east-southeast to north-south compression. Late events such as northeast-southwest and north-south extension and
northeast-southwest compression have also been recognized.
Rationalized detailed gravity data, southern Saskatchewan
Authors: Miles W F , Roest W R , Kelley L , Gent M
Published: November 2010

This open file is a compilation of more than 150 separate detailed gravity surveys, levelled to a common datum. The datum is represented by the regional gravity data holdings of the National Gravity Anomaly Data Base maintained by the Geodetic Survey Division of
Geomatics Canada. The national data are tied to the International Gravity Standardization Network 1971 (IGSN71) and are included in this compilation.
The levelled data are presented on a CD-ROM as a PC binary file of 230,312 records. Each record contains 31 fields. The binary data may be manipulated using the program 'RET_256.COM'. This program is included on the CD and will run on any 386 or higher PC. 'RET_256' allows the user to extract
subsets of the data based on area or survey. Areas are defined by latitude and longitude ranges and surveys are defined by a range of project numbers. The user may also recalculate Bouguer gravity anomalies using user-specified Bouguer densities (rock, water and ice) in order to better represent
local crustal densities. In addition, the anomalies may be recalculated using the three most common geoid models: WGS84, GRS67 or Potsdam 1930.
Periodicity Detection Method for Small-Sample Time Series Datasets
Authors: Tominaga Daisuke
Published: November 2010

Time series of gene expression often exhibit periodic behavior under the influence of multiple signal pathways, and are represented by a model that incorporates multiple harmonics and noise. Most of these data, which are observed using DNA microarrays, consist of few sampling points in time, but most periodicity detection methods require a relatively large number of sampling points. We have previously developed a detection algorithm based on the discrete Fourier transform and Akaike's information criterion. Here we demonstrate the performance of the algorithm for small-sample time series data through a comparison with conventional and newly proposed periodicity detection methods based on a statistical analysis of the power of harmonics.

We show that this method has higher sensitivity for data consisting of multiple harmonics, and is more robust against noise than other methods. Although “combinatorial explosion” occurs for large datasets, the computational time is not a problem for small-sample datasets. The MATLAB/GNU Octave script of the algorithm is available on the author's web site: http://www.cbrc.jp/%7Etominaga/piccolo/ .
An Interaction of the Pre- and Post-Weaning Diets Rich in Omega-6 Polyunsaturated Fats Alters Plasma Lipids, Hepatic Gene Expression and Aortic Vascular Reactivity in Adult 057Bl/6 Mice
Authors: Chechi Kanta , McGuire John J. , Cheema Sukhinder K.
Published: November 2010

Aim

To investigate the effects of diets rich in n-6 polyunsaturated fats (PUFA) fed during pre- and post-weaning time periods on the lipid metabolism and vascular reactivity in adult C57Bl/6 mice, in order to assess the impact of maternal nutrition and its interaction with the offspring diet on the metabolism of adult offspring.

Methods

Female C57Bl/6 mice were fed a high-fat diet enriched with n-6 PUFA (P) or control diet (C) for 2-weeks before, during mating, gestation and lactation, while their pups received either P or C for 8-weeks post-weaning.

Results

A significant interaction between the maternal and post-weaning diets was observed for the offspring body weight, food-, caloric-intake, plasma lipids, hepatic mRNA expression of lecithin cholesterol acyltransferase, aortic contractile and relaxation responses ( P < 0.05).

Conclusion

The overall metabolic and physiological outcome in the offspring is dependent upon the interaction between the pre- and post-weaning dietary environments.
An Explicit Polynomial Expression for a q-Analogue of the 9- j Symbols
Authors: Rahman Mizan
Published: November 2010

Using standard transformation and summation formulas for basic hypergeometric series we obtain an explicit polynomial form of the q-analogue of the 9- j symbols, introduced by the author in a recent publication. We also consider a limiting case in which the 9- j symbol factors into two Hahn polynomials. The same factorization occurs in another limit case of the corresponding q-analogue.
Role stressors, participative control, and subjective fit with organisational values: Main and moderating effects on employee outcomes
Authors: Newton Cameron J , Jimmieson Nerina L
Published: November 2010

Research investigating Karasek's (1979) Demand–Control Model (D-CM) has produced mixed results relating to the stress-buffering effects of job decision latitude, or job control, on employee adjustment. Cited reasons for these mixed results include the way control is operationalised and also the potential effects of secondary moderators in the relationship among job demand, job control, and employee adjustment. Towards addressing these issues, the present study assessed the secondary moderating effects of subjective fit with organisational culture and values in the D-CM. Participation in decision-making was used as the measure of job control. Moderated multiple regression analyses revealed three significant interactions in a sample of 119 employees. The results revealed a three-way interaction between role overload, participative control, and subjective fit on physiological symptoms and psychological health. Further analyses demonstrated a significant interaction between role conflict, participative control, and subjective fit on intentions to leave. In all interactions, participative control buffered the negative effects of the stressors on levels of employee adjustment only when employees' subjective fit with the organisational values was high. The theoretical importance and practical implications of the results are discussed.
Differences between family and non-family SMEs: A comparative study of Australia and Belgium
Authors: Smith Max
Published: November 2010

This study attempts to further the development of family business theory by providing a more detailed understanding of the differences between family and non-family firms' profitability, growth, exporting and networking behaviour. Utilising data from 2190 Australian SMEs, the study compares the Australian experience of differences between family and non-family firms with those found among Belgium firms. The Australian results are consistent with the growth and some of the networking behaviour found among Belgium firms, but not with their profitability and exporting behaviour. The study's findings support the contentions that the differences between family and non-family firms may be less than many earlier studies have indicated and that industry differences and cross-national differences in corporate governance environments may lead to variances in these differences. It also demonstrates that the underlying theoretical rationale for a number of predicted differences between family and non-family firms appears flawed. These findings indicate that new empirical studies that control for context are urgently needed to ensure the scholarly literature on family businesses is not being built on false assumptions. They also indicate that studies designed to explain differences in the family/non-family business relationship between industries and nations may lead to advances in family business theory.
Latitudinal distributions of organic nitrogen and organic carbon in marine aerosols over the western North Pacific
Authors: Miyazaki Y. , Kawamura K. , Jung J. , Furutani H. , Uematsu M.
Published: November 2010

Abstract. Marine aerosol samples were collected over the western North Pacific along the latitudinal transect from 44° N to 10° N in late summer 2008 for measurements of organic nitrogen (ON) and organic carbon (OC) as well as isotopic ratios of total nitrogen (TN) and total carbon (TC). Increased concentrations of methanesulfonic acid (MSA) and diethylammonium (DEA+) at 40–44° N and subtropical regions (10–20° N) together with averaged satellite chlorophyll a data and 5-day back trajectories suggest a significant influence of marine biological activities on aerosols in these regions. ON exhibited increased concentrations up to 260 ngN m−3 in these marine biologically influenced aerosols. Water-insoluble organic nitrogen (WION) was found to be the most abundant nitrogen in the aerosols, accounting for 55 ± 16% of total aerosol nitrogen. In particular, the average WION/ON ratio was as high as 0.93 ± 0.07 at 40–44° N. These results suggest that marine biological sources significantly contributed to ON, a majority of which is composed of water-insoluble fractions in the study region. Analysis of the stable carbon isotopic ratios (δ13C) indicated that, on average, marine-derived carbon accounted for ~88 ± 12% of total carbon in the aerosols. In addition, the δ13C increased from −22 to −20‰ when ON/OC ratios increased from 0.15 to 0.35 in marine biologically influenced aerosols. These results clearly show that organic nitrogen is enriched in organic aerosols originated from an oceanic region with high biological productivity, indicating a preferential transfer of nitrogen-containing organic compounds from the sea surface to the marine atmosphere. Both WION concentrations and WION/water-insoluble organic carbon (WIOC) ratios showed positive correlations with local wind speeds, suggesting that sea-to-air emissions of ON via sea spray significantly contributes to marine organic aerosols over the study region.
Quantitative and enantioselective analysis of monoterpenes from plant chambers and in ambient air using SPME
Authors: Yassaa N. , Custer T. , Song W. , Pech F. , Kesselmeier J. , Williams J.
Published: November 2010

Abstract. A headspace solid-phase microextraction (HS-SPME) and gas chromatography/mass spectrometry (GC/MS) system has been developed for quantifying enantiomeric and nonenantiomeric monoterpenes in plant chamber studies and ambient air. Performance of this system was checked using a capillary diffusion system to produce monoterpene standards. The adsorption efficiency, competitive adsorption and chromatographic peak resolution of monoterpene enantiomer pairs were compared for three SPME fibre coatings: 75 μm Carboxen-PDMS (CAR-PDMS), 50/30 μm divinylbenzene-carboxen-polydimethylsiloxane (DVB-CAR-PDMS) and 65 μm divinylbenzene-polydimethylsiloxane (DVB-PDMS). Key parameters such as the linearity and reproducibility of the SPME system have been investigated in this work. The best compromise between the enantiomeric separation of monoterpenes and competitive adsorption of the isoprenoids on the solid SPME fibre coating was found for DVB-PDMS fibres. The optimum conditions using DVB-PDMS fibres were applied to measure the exchange rates of monoterpenes in the emission of Quercus ilex using a laboratory whole plant enclosure under light and dark conditions, as well as in ambient air. With 592 and 223 ng m−2 s−1 respectively, β-myrcene and limonene were the predominant monoterpenes in the emission of Q. ilex. These values were closely comparable to those obtained using a zNose and cartridge GC-FID systems.
Intercomparison of slant column measurements of NO2 and O4 by MAX-DOAS and zenith-sky UV and visible spectrometers
Authors: Roscoe H. K. , Van Roozendael M. , Fayt C. , du Piesanie A. , Abuhassan N. , Adams C. , Akrami M. , Cede A. , Chong J. , Clémer K. , Friess U. , Gil Ojeda M. , Goutail F. , Graves R. , Griesfeller A. , Grossmann K. , Hemerijckx G. , Hendrick F. , Herman J. , Hermans C. , Irie H. , Johnston P. V. , Kanaya Y. , Kreher K. , Leigh R. , Merlaud A. , Mount G. H. , Navarro M. , Oetjen H. , Pazmino A. , Perez-Camacho M. , Peters E. , Pinardi G. , Puentedura O. , Richter A. , Schönhardt A. , Shaiganfar R. , Spinei E. , Strong K. , Takashima H. , Vlemmix T. , Vrekoussis M. , Wagner T. , Wittrock F. , Yela M. , Yilmaz S. , Boersma F. , Hains J. , Kroon M. , Piters A. , Kim Y. J.
Published: November 2010

Abstract. In June 2009, 22 spectrometers from 14 institutes measured tropospheric and stratospheric NO2 from the ground for more than 11 days during the Cabauw Intercomparison Campaign of Nitrogen Dioxide measuring Instruments (CINDI), at Cabauw, NL (51.97° N, 4.93° E). All visible instruments used a common wavelength range and set of cross sections for the spectral analysis. Most of the instruments were of the multi-axis design with analysis by differential spectroscopy software (MAX-DOAS), whose non-zenith slant columns were compared by examining slopes of their least-squares straight line fits to mean values of a selection of instruments, after taking 30-min averages. Zenith slant columns near twilight were compared by fits to interpolated values of a reference instrument, then normalised by the mean of the slopes of the best instruments. For visible MAX-DOAS instruments, the means of the fitted slopes for NO2 and O4 of all except one instrument were within 10% of unity at almost all non-zenith elevations, and most were within 5%. Values for UV MAX-DOAS instruments were almost as good, being 12% and 7%, respectively. For visible instruments at zenith near twilight, the means of the fitted slopes of all instruments were within 5% of unity. This level of agreement is as good as that of previous intercomparisons, despite the site not being ideal for zenith twilight measurements. It bodes well for the future of measurements of tropospheric NO2, as previous intercomparisons were only for zenith instruments focussing on stratospheric NO2, with their longer heritage.
Carbonate sedimentation and effects of eutrophication observed at the Kališta subaquatic springs in Lake Ohrid (Macedonia)
Authors: Matter M. , Anselmetti F. S. , Jordanoska B. , Wagner B. , Wessels M. , Wüest A.
Published: November 2010

Abstract. To date, little is known about the role of spring waters with respect to authigenic carbonate precipitation in a shallow lacustrine setting. Lake Ohrid, located in Southeastern Europe, is a large lake fed to over 50% by karstic springs of which half enter subaquatically and influence significantly its ecology and species distribution. In order to evaluate how sedimentological processes are influenced by such shallow-water springs, the Kališta subaquatic spring area in the north west of Lake Ohrid was investigated by a sidescan sonar survey and with sediment traps and three transects of gravity short cores. Results indicate that sedimentation in the spring area is dominated by authigenic carbonate precipitation. High sedimentation rates and evidences for bio-induced precipitation processes were observed in the water column and in the sediments. Two distinct stratigraphic units characterize the shallow subsurface, both composed of carbonate silts with high carbonate contents of up to 96%, but differing in color, carbonate content and diatom content. A chronological correlation of the cores by radiocarbon dates and 137Cs activities places the transition between the two stratigraphic units after ~1955 AD. At that time, coastal sedimentation changed drastically to significantly darker sediments with higher contents of organic matter and more abundant diatoms. This change coincides with the recent human impact of littoral eutrophication.
Ultrahigh-Pressure Angioplasty versus the Peripheral Cutting Balloon™ for Treatment of Stenoses in Autogenous Fistulas: Comparison of Immediate Results
Authors: Kundu Sanjoy , Clemens Rick , Aziza Jonathan , Tam Paul , Nagai Gordon , You John , Au Victoria
Published: November 2010

Purpose

To compare the immediate results of ultrahigh-pressure (UHP) balloons vs. peripheral cutting balloons (PCB) for the treatment of stenoses associated with autogenous fistulas using intra-access blood flow measurements.

Materials and Methods

This prospective randomized study consisted of 22 hemodialysis (HD) patients with autogenous fistulas who had decreased intra-access blood flow (<500 mL/min). All patients underwent a fistulogram and intraprocedural blood flow measurements. Patients were randomized once into two groups; one group undergoing UHP angioplasty and the second group undergoing PCB angioplasty. Randomization occurred once after the diagnostic fistulogram and each patient in each arm only underwent percutaneous transluminal angioplasty with either UHP or PCB. The study cohort consisted of 12 patients in the UHP group and 10 patients in the PCB group. Data collected included fistula anatomy, degree of stenosis, length of stenosis, balloon specifications and residual stenosis.

Results

The 22 study patients underwent 35 angioplasty procedures; 23 in the UHP group (12 patients) and 12 in the PCB group (10 patients). The technical success rate was 91%. The pre-intervention mean blood flow was 288 mL/min in the UHP group and 391 mL/min in the PCB group. The post-intervention mean blood flow was 613 mL/min in the UHP group and 606 mL/min in the PCB group. The mean increase in blood flow was 325.8 mL/min in the UHP group and 213 mL/min in the PCB group. This represents a relative mean increase in blood flow of 253% in the UHP group and 85% in the PCB group. An unpaired t-test showed there was no significant difference between the groups with respect to pre-flow, post-flow, and mean and relative mean increase in flow. There were two failures; one in the UHP group and one in the PCB group. There was one minor complication (2.8%) but no major complications.

Conclusions

In this small group of HD patients with autogenous fistulas our comparison of UHP to the PCB demonstrated that the immediate results, as determined by measurement of intra-access blood flow, were equivalent. Further long-term follow-up will be required to determine the longevity of these results
Central Vein Stenosis or Occlusion Associated with Cardiac Rhythm Management Device Leads in Hemodialysis Patients with Ipsilateral Arteriovenous Access: A Retrospective Study of Treatment Using Stents or Stent-Grafts
Authors: Saad Theodore F. , Myers G. Robert , Cicone Jeffrey
Published: November 2010

Purpose

Symptomatic central vein stenosis commonly occurs when cardiac rhythm management device (CRMD) leads are placed via the subclavian vein ipsilateral to arteriovenous (AV) hemodialysis (HD) access. The purposes of this study were to determine the outcomes, complications, and patency following stenting of CRMD lead-associated central vein stenosis or occlusion, and to determine the effect of stents on CRMD function.

Methods

Fourteen HD patients with AV access and an ipsilateral CRMD were treated with stents for symptomatic central vein stenosis or occlusion following inadequate response to angioplasty from January 2005 to December 2009. Subsequent access interventions, complications, and outcomes were reviewed retrospectively. Cardiology records were examined to assess CRMD function.

Results

Treatment of stenosis or occlusion with angioplasty and stenting resulted in 100% procedural success and no complications. At 6 and 12 months, respectively, primary patency rates were 45.5% and 9.0%; primary-assisted patency rates were 90.9% and 80.0%; secondary patency rates were 100% and 90.0%. There were 42 repeat interventions performed in 12 patients; five received additional stents. The mean number of subsequent interventions was 3.2 per patient (2.1 per patient-year). All CRMD testing demonstrated normal function with no device or lead failure. Seven of the 14 subjects died resulting in a 35.3% annual mortality rate. No deaths were attributable to dysrhythmia or CRMD failure and no patient required CRMD removal or exchange.

Conclusions

Placement of stents for CRMD lead-associated stenosis or occlusion yields high success and low complication rates with no effect on CRMD function. Patency rates are similar to those reported in other series of central venous stents.
Clinical Outcome of Overlapping Stents in Hemodialysis Access
Authors: Chan Micah R. , Yevzlin Alexander S.
Published: November 2010

Purpose

Endovascular stents have recently been shown to extend access patency in thrombosed and stenotic arteriovenous grafts. Given this improved patency, stent placement has outpaced balloon angioplasty in hemodialysis (HD) access interventions. However, concern remains over localized corrosion and increased neointimal hyperplasia of overlapping stents in the access circuit and whether this promotes premature stent failure.

Methods

This is a retrospective analysis of HD patients referred for access dysfunction during a 2-yr period. Using a prospectively collected, vascular access database, we identified 76 patients seen for follow-up angiography due to access dysfunction after stent placement. We compared the outcomes of overlapping vs. non-overlapping stents in measured primary assisted patency and mean percent luminal diameter as a marker of lesion severity.

Results

The two groups did not differ significantly in demographics or comorbid conditions. Only gender had a significant discrepancy between the two groups, with 65.5% vs. 42.9% male (p=0.01) in the overlapping vs. non-overlapping stent groups, respectively. The mean percent luminal stenosis was found to be 83.7 ± 17.3 and 85.5 ± 12.6 (p=0.55) for the overlapping vs. non-overlapping stent groups, respectively. For overlapping and non-overlapping stents, 30-day primary patency was 94% and 89%, respectively, 60-day primary patency was 77% and 63%, respectively, and 90-day primary patency was 68% and 50%, respectively. Using multiple regression analysis, no risk factors were identified to be associated with the severity of luminal stenosis. No identifiable risk factors were found to be associated with improved primary patency. In particular, overlapping vs. non-overlapping stents were not identified as a statistically significant factor influencing primary (assisted) patency (hazards ratio 0.60; 95% cI 0.34 to 1.06; p>0.05).

Conclusions

This study provides evidence that the theoretical concern of metal on metal corrosion and increased neointimal hyperplasia that can be seen with overlapping stents does not play a significant clinical role.
Ultrasound-Guided Central Venous Catheter Placement by Surgical Trainees: A Safe Procedure?
Authors: Hameeteman Marijn , Bode Aron S. , Peppelenbosch Arnoud G. , Van der Sande Frank M. , Tordoir Jan H.M.
Published: November 2010

Background

Central venous catheters (CVCs) are widely used to create a temporary or long-term access to the central venous system. A variety of treatments require a functional central venous access, including hemodialysis, administration of drugs, plasmapheresis and parenteral nutrition. The aim of this study was to evaluate the results of CVC placement performed by surgical trainees, according to a strict protocol of ultrasound-guided puncture and fluoroscopy-guided catheter insertion in a large teaching hospital in an outpatient setting.

Methods

Between 1 January 2006 and 31 December 2008, 539 CVCs were placed, of which 486 were primary inserted by surgical trainees. All placements were ultrasound- and fluoroscopy-guided. After every placement operators recorded type of catheter, type of anesthesia, subcutaneous tunneling, technique of insertion and complications.

Results

The study population consisted of 52% males. Access sites of CVCs were the internal jugular vein (91%), subclavian vein (5%) and other veins (3%). Technical success rate was 96.5%. Complication rate was 8.4%, of which 93% were arterial punctures. Pneumothorax occurred in three patients.

Conclusions

CVC placement by surgical trainees is a safe procedure when using a strict protocol of ultrasound-guided vessel puncture and fluoroscopic-guided catheter placement.
Simple and Durable Resolution of Steal Syndrome by Conversion of Brachial Artery Arteriovenous Fistulas to Proximal Radial Artery Inflow
Authors: Beecher Brett A. , Taubman Kevin E. , Jennings William C.
Published: November 2010

Dialysis associated steal syndrome (DASS) is relatively uncommon but constitutes a serious risk for patients undergoing vascular access operations. We report two patients with DASS where brachial artery vascular access inflow was revised to the proximal radial artery for arteriovenous fistula (AVF) inflow. DASS was resolved in both patients with the permanent resolution of symptoms, in addition to the healing of ulcerations and ischemia. Both AVFs were immediately functional and durable.
Endothelial Function Predicts Positive Arterial-Venous Fistula Remodeling in Subjects with Stage IV and V Chronic Kidney Disease
Authors: Owens Christopher D. , Wake Nicole , Min Kim Ji , Hentschel Dirk , Conte Michael S. , Schanzer Andres
Published: November 2010

Purpose

The maturation of an arteriovenous fistula (AVF) requires remodeling of the arterial inflow and the venous outflow limbs to sustain flows sufficient to support hemodialysis. However, factors influencing remodeling of AVF are poorly understood. We hypothesized that AVF remodeling was an endothelium-dependent process.

Methods

This is a prospective cohort study of patients (n=25) undergoing autologous AVF formation. Brachial artery vasoreactivity studies were performed pre-operatively to assess endothelium-dependent, flow-mediated vasodilation (FMD). High-resolution ultrasound was used to assess venous and arterial diameters intraoperatively, and at 3 months.

Results

The mean age was 64.5 ± 13.6 yrs. Twelve patients (48%) had diabetes. The mean FMD for the entire cohort was (mean ± SEM) 5.82 ± 0.9%, (range) 0–17.3%. The vein increased in size 3.19 ± .28 to 6.11 ± .41 mm, 108.4 ± 17.9%, p=.0001, while the artery increased from 3.29 ± .14 to 4.48 ± .30 mm, 20.47 ± 10.8%, p=.013. There was a significant positive correlation between the degree of arterial and venous remodeling, r=.52, p=.023. Brachial artery FMD most strongly correlated with the magnitude of arterial remodeling, r=.47, p=.038. Patients with diabetes failed to undergo venous remodeling to the same extent as did those without diabetes, 59.2 ± 24.4% vs. 141.5 ± 25.4%, p=.04.

Conclusion

Impairment of endothelial function is associated with decreased arterial remodeling and final venous lumen diameter attained at 3 months. Further investigation is needed to determine whether modulation of endothelial function in this cohort can improve AVF maturation.
Mechanical Lock of the Lumen: Researching towards new Approaches for Permanent Vascular Access
Authors: Bosticardo Gianmario
Published: November 2010

Purpose

Theoretical proposals for two new vascular access devices (a central venous catheter (CVC) and a peripheral vascular access system, PVAS) are presented in this article.

Methods

The new CVC concept is based on a mechanical obturator used for CVC locking. Compared to conventional locks, it should, theoretically, allow the reduction of bacterial contamination, biofilm and thrombotic formation. A new tunneling technique, based on a “rigid tunnel sheath” providing a more stable connection, as compared to a traditional CVC cuff, and an increasingly protected exit site, allows CVC changeover to take place through the sheath; therefore, avoiding surgical intervention. PVAS, based on the same mechanical lock concept, is structured from four components: obturator, soft graft, rigid tunnel sheath and foldable sheath. The total graft length is about 80 mm, its inner extremity being uncovered to allow a gentle curve reaching the native vessel. The outer extremity and bifurcation are reinforced by a titanium rigid sheath together with a Dacron cuff. The obturator is protected, and several technical solutions have been considered to guarantee sterility: the “accordion sheath”, the “foldable sheath”, and the “balloon obturator system”.

Results

The major advantage of PVAS on CVC is the implant on the peripheral vessel which allows the saving of central veins and possibly avoiding life-threatening complications. As compared with an arterial-venous fistula or an arterial-venous graft, PVAS's main advantage should be the possibility of implanting even in “desperate” cases, so avoiding fistula needle positioning. It could be indicated for pediatric or psychiatric patients, for home-based or frequent dialysis schedules. Lower hemodynamic stress should therefore reduce vessel damage, such as aneurism, pseudo-aneurism, intimal hyperplasia and cardiac overload.

Conclusions

The development of prototypes is in progress to verify both device usefulness and safety in clinical practice.
Juxta-Anastomotic Stenosis of Native Arteriovenous Fistulas: Surgical Treatment versus Percutaneous Transluminal Angioplasty
Authors: Napoli Marcello , Prudenzano Raffaele , Russo Francesco , Lucia Antonaci Assunta , Aprile Maria , Buongiorno Erasmo
Published: November 2010

Purpose

Juxta-anastomotic stenosis (JAS) is a complication of arteriovenous fistulas (AVFs). Both surgical revision (SR) and percutaneous transluminal angioplasty (PTA) may correct JAS. In this study we compare the results for SR treatment versus PTA.

Methods

From January 2005 until December 2008, 66 PTA and 68 SR were performed in 43 and 57 uremic pts with JAS of the native AVF, respectively. Efficacy of SR and PTA was evaluated measuring brachial arterial flow (BAF) by CDU. The Kaplan-Meier table of primary and assisted primary patency was analyzed.

Results

PTA was attempted in 50 patients. PTA failed in 7 patients and they were switched to SR. In 43 pts, PTA produced a favorable effect, with a mean increase of 99 ± 70% (p<0.001) in blood flow. Restenosis occurred in 17 pts: 2 were treated by SR and 15 by PTA. Restenosis occurred again in 6/15 pts: after second restenosis, 5/6 pts received a third PTA with stenting, 1 patient underwent SR. The failure of access occurred after 12–17 months in 3 pts. In 57/57 JAS treated by SR, a new well-functioning fistula was created upstream of the stenosis, with a mean increase of 102 ± 71% in blood flow (p<0.001). Restenosis occurred in 15 pts: 9 were treated by SR and 6 by PTA. Access failure occurred after 3–36 months in 9 pts. The Kaplan-Meier table showed a better primary patency for SR (p<0.05) without difference in assisted primary patency.

Conclusions

SR showed a better primary patency then PTA, confirming the trend to stenosis relapse after PTA. So, as PTA does not exclude a later correction of the JAS, the similar assisted patency suggests to perform a PTA first, reserving SR for after its failure.
Comparison among Transposed Brachiobasilic, Brachiobrachial Arteriovenous Fistulas and Flixene™ Vascular Graft
Authors: Lioupis Christos , Mistry Hiren , Rix Tom , Chandak Pankaj , Tyrrell Mark , Valenti Domenico
Published: November 2010

Objective

To compare the outcomes of 3 upper arm access types: transposed brachiobasilic arteriovenous fistula (BBAVF), autogenous brachial vein–brachial artery access (ABBA), and a new type of ePTFE graft (Flixene™ graft) (AVG), in a consecutive series of patients treated in a tertiary centre.

Methods

A prospective, computerized access database was analysed retrospectively to identify all patients undergoing BBAVF, ABBA, or AVG between January 1, 2008, and December 31, 2009.

Results

A total of 108 patients were identified; of whom 45 had BBAVF, 15 ABBA, and 48 ePTFE brachioaxillary AVG. Early failure was similar in all 3 groups. The 18–month functional patency rates for the ABBAs, BBAVFs, and grafts were 27%, 51%, and 55%, respectively. The median time to first use for AVGs was significantly shorter (p<0.0001). Complications were not more frequent in AVGs than ABBAs and BBAVFs (p=0.127). The total number of access interventions was similar between the AVG and ABBA groups (p=0.58), but it was significantly higher in the AVG group compared with the BBAVF group (p<0.0001).

Conclusions

This study supports the current recommendations of the NKF Kidney Disease Outcomes Quality Initiative for using BBAVFs as third choice after radiocephalic and brachiocephalic arteriovenous fistulas. We also showed good results with a new type of prosthetic graft (Flixene™ graft) that allows cannulation within days of implantation. We now favour the use of this graft instead of basilic vein transposition in elderly patients with short life expectancy and urgent need of renal access.
Cardiovascular Remodeling during Arteriovenous Fistula Maturation in a Rodent Uremia Model
Authors: Langer Stephan , Paulus Niklas , Koeppel Thomas A. , Greiner Andreas , Buhl Alexandra , Krombach Gabriele A. , Jacobs Michael J. , Kennes Lieven , Kokozidou Maria
Published: November 2010

Purpose

The aim of this study was to evaluate cardiovascular remodeling after arteriovenous fistula (AVF) surgery and to characterize the effect of chronic kidney disease (CKD) in a rodent femoral AVF model.

Methods

Sixteen rats (8 healthy; 8 CKD) underwent femoral AVF surgery; 4 animals served as controls. AVF and cardiac morphology as well as function were assessed during the fistula maturation process (until day 84 after surgery) using magnetic resonance imaging and histopathological analyses.

Results

Histopathological analysis revealed that a glomerular and interstitial nephropathy caused CKD. In healthy and CKD animals, AVF surgery resulted in progressive downstream vein dilation and a subsequent cardiac adaptation. This vein dilation during maturation was less in CKD rats during the early postoperative course (day 21: p=0.0475) and similar thereafter until day 84. The dilation was accompanied by an aggravation of neointimal hyperplasia (NIH) and calcification in AVFs of CKD rats. The chronic volume overload resulted in both groups in a significantly increased end-diastolic volume (healthy rats: p=0.0087; CKD rats: p=0.0333). Simultaneously, cardiac output increased 195% in healthy and 244% in uremic rats, which was caused by both a significantly increased stroke volume and heart rate. The left ventricular mass rose in AVF animals and was increased at the end of the study period, indicating a distinct cardiac hypertrophy.

Conclusion

Our rat model showed typical cardiovascular features of the AVF maturation process, which strongly resemble clinical findings in patients. Uremia caused inferior dilation in the early phase after surgery and an exacerbation of NIH. This model should help to identify the cellular and molecular mechanisms that contribute to AVF failure.
Mediastinal Approach to the Placement of Tunneled Hemodialysis Catheters in Patients with Central Vein Occlusion in an Outpatient Access Center
Authors: Matsuura John , Dietrich Anne , Steuben Stephanie , Ricker Jaren , Barkema Karla , Kuhl Taften
Published: November 2010

Objectives

Endovascular therapy for hemodialysis (HD) access is now performed in outpatient centers in a growing number of cities in the US. As patients live longer, we are facing a growing number of patients with central venous occlusion. We report our first three cases of mediastinal tunneled dialysis catheter placement in a clinic setting.

Methods

Between 15 November 2009 and 1 April 2010, three patients with central vein occlusion required tunneled HD catheter placement. Case #1 was a 60–year-old male with left subclavian and innominate vein occlusion from a defibrillator pacemaker and two previous right internal jugular tunneled dialysis catheters with occlusion of the right internal jugular vein. He lost right arm access after two failed arteriovenous fistulas (AVF) and an occluded upper arm AV graft. His last right external jugular catheter was removed for infection. Case #2 was a 72–year-old female with a thrombosed left upper arm and a right basilic vein AV access. She had a history of left leg deep vein thrombosis (DVT) and a vena cava filter. The left and right internal jugular veins were occluded as well as the left subclavian vein after stent placement. She required a tunneled HD catheter after a failed attempt at endovascular salvage of her right basilic AVF. Case #3 was a 78–year-old female who had been on HD for 4 yr. She refused AVF surgery and had four tunneled HD catheters removed for infection. She presented with bilateral internal jugular vein thrombosis and the removal of an infected right subclavian tunneled HD catheter. The technique: The dialysis catheters were placed using standard C-arm fluoroscopy. We accessed the right femoral vein to pass a Berenstein catheter (Cordis, Inc, Warren, NJ) into the right innominate-subclavian vein junction. Using the catheter as a fluoroscopic target, a micropuncture needle was guided into the right innominate vein and a standard J-guidewire was used to dilate the mediastinal tract and place a new tunneled dialysis catheter.

Results

In all three cases, the tunneled dialysis catheters were placed under local anesthesia with no intravenous sedation. No pneumothorax occurred and all three catheters were used for HD within 24 hr. Two catheters were removed at 3 and 4 months for infection. One catheter continues to function well.

Conclusions

As the lifespan of our dialysis patient population continues to improve, we will see an increasing need to perform complicated access procedures to maintain HD support. These three cases emphasize the value of the transmediastinal technique using basic C-arm fluoroscopy and a limited stock of basic catheters and guidewires.
Synthesis, characterization and catalytic performance of SAPO‐34 molecular sieves for methanol‐to‐olefin (MTO) reaction
Authors: Wang Qian , Wang Lei , Wang Hui , Li Zengxi , Wu Hui , Li Guangming , Zhang Xiangping , Zhang Suojiang
Published: November 2010

The methanol‐to‐olefin (MTO) process is important because it offers an alternative to the conventional oil route for the conversion of natural gas or coal to light olefins. The most promising catalysts for the MTO reaction are solid acids with a zeolite structure, where reactants and products such as ethylene and propylene may freely diffuse through active catalysts, but products with larger kinetic diameters are trapped within the cages. In this work, SAPO‐34 molecular sieves were synthesized by hydrothermal crystallization, using triethylamine (TEA) as the template. These samples were characterized by X‐ray diffraction, scanning electron microscopy, thermo‐gravimetric analysis–differential scanning calorimetry, energy dispersive spectroscopy, Fourier transform‐infrared (FT‐IR) and N2 adsorption–desorption. The effects of template concentration and crystallization time on the physicochemical properties and catalytic performance were investigated. The crystallinity and morphology of SAPO‐34 were influenced by the concentration of the template. Pure SAPO‐34 was obtained when the TEA/Al2O3 molar ratio was higher than 2.0. With increased crystallization time, the Si content in SAPO‐34 crystals increased, which influenced the surface acidity. FT‐IR spectra indicated that all samples were dominated by Lewis acid sites and the sample crystallized for 11 h exhibited the lowest number of Lewis acid sites. The catalytic performance of SAPO‐34 was tested with the MTO reaction. High selectivity to olefins (C2H4 + C3H6) was obtained over the catalyst synthesized with a TEA/Al2O3 ratio of 3.0 and crystallization time of 11 h. At the reaction temperature of 450 °C, the methanol conversion approached 100% and the yield of C2C4 olefins was more than 80%. Hence, SAPO‐34 molecular sieves were shown to be excellent catalysts for the MTO reaction. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
A simple and sensitive HPLC‐UV method for the determination of ponicidin in rat plasma and its application in a pharmacokinetic study
Authors: Li Xiaotian , Hou Wenjing , Song Jingjing , Liu Hongmin , Song Shumei , Zhang Lingchun , Shi Yingying
Published: November 2010

A simple, rapid, selective and sensitive HPLC‐UV method has been developed and validated for the determination of ponicidin in rat plasma. The analyte was extracted from rat plasma by liquid–liquid extraction with ethyl acetate as the extraction solvent. The LC separation was performed on a Zorbax Eclipse XDB C18 analytical column (150 × 4.6 mm i.d., 5 µm) with an isocratic mobile phase consisting of methanol–water–phosphoric acid (45:55:0.01, v/v/v) at a flow rate of 1.0 mL/min. There was a good linearity over the range of 0.1–25 µg/mL (r = 0.9995) with a weighted (1/C2) least square method. The lower limit of quantification was proved to be 0.1 µg/mL. The accuracy was within ±10.0% in terms of relative error and the intra‐ and inter‐day precisions were less than 9.1% in terms of relative standard deviation. After validation, the method was successfully applied to characterize the pharmacokinetics of ponicidin in rats. Copyright © 2010 John Wiley & Sons, Ltd.
Cover Picture: Eur. J. Immunol. 12/10
Authors: Archambaud Cristel , Salcedo Suzana P. , Lelouard Hugues , Devilard Elisabeth , de Bovis Beatrice , Van Rooijen Nico , Gorvel Jean‐Pierre , Malissen Bernard
Published: November 2010

The cover image of this issue consists of a confocal image of a mediastinal draining lymph node (MdLN) section, taken 5 days post‐infection of C57BL/6 mice with DsRed‐expressing Brucella (red). Md1N sections were also stained for lysozyme (green) and MHCII (blue). This image was taken from Archambaud et al. (pp. 3458–3471). In this article the authors investigate the initial innate immune response that follows intranasal inoculation of Brucella abortus in the mouse. The authors demonstrate that alveolar macrophages are critical regulators of the initial innate immune response against Brucella within the lungs, and that pulmonary DC and alveolar macrophages play distinct roles in controlling initial pulmonary Brucella infection.