Changes In Mean Diameter Research Articles

Vein Diameter on Unenhanced Multidetector CT Predicts Reperfusion of Pulmonary Arteriovenous Malformation after Embolotherapy.

To evaluate the value of the diameter of the draining vein of pulmonary arteriovenous malformation (PAVM) on unenhanced chest MDCT in diagnosing reperfusion after percutaneous vaso-occlusion therapy. We retrospectively reviewed our long-term experience of patients with hereditary haemorrhagic telangiectasia and selected cases on the following criteria: an initial pulmonary angiogram with embolotherapy of at least one PAVM, a follow-up MDCT examination in the following year followed by a second pulmonary angiogram with embolotherapy if needed. Follow-up unenhanced chest MDCT examinations were analyzed blindly from results of pulmonary artery angiogram and clinical data, the diameter of the efferent vein close to the PAVM sac was measured, then compared to those of pulmonary artery angiogram as a gold standard. Eighty-eight of 100 patients met inclusion criteria, in whom 62 of 176 PAVMs were reperfused at angiogram. The mean diameter of the efferent vein on MDCT was 4.3 ± 2.1mm in patent PAVMs and 1.8 ± 0.9mm in non-patent PAVMs (p < 0.0001). The optimal cutoff diameter based on ROC analysis was 2.5mm (sensitivity = 98.4%; specificity = 87.7%). A diameter of the draining vein of PAVM of 2.5mm or greater on unenhanced MDCT is a strong predictor of reperfusion. • Diameter of draining vein of 2.5mm or greater is associated with reperfusion. • Unenhanced chest MDCT predicts reperfusion of PAVMs with good sensitivity and specificity. • Unenhanced MDCT can guide a decision of repeat pulmonary angiogram and embolotherapy. • The mean vein diameter change of PAVMs occluded at follow-up is 3.8mm. • Overall success rate after a median of 6months embolotherapy was 64.7 %.

Combustion and emission characteristics of a direct-injection gasoline engine using the MMT fuel additive gasoline

In recent years, Methyl-cyclopentadienyl Manganese Tricarbonyl (MMT) has been widely used as a gasoline additive to improve the octane rating and antiknock of the fuel. Meanwhile, particulate emissions from the gasoline direct injection (GDI) engine have become a subject of concern. This study is aimed to investigate the impact of fuel (ultralow sulfur gasoline with the additive MMT) on the combustion characteristic, gaseous emissions (HC, CO and NOx) and particulate matter (PM) emissions in a GDI research engine, under the operating conditions of stoichiometric air/fuel ratio, 2000rpm engine speed and 30–150Nm engine torque. The experimental results show that, in the GDI engine, the cylinder pressure increases slightly with the increase of MMT content in the test fuels. The use of MMT increases the peak heat release rate and ignition delay slightly but the combustion duration does not change significantly. Depending on the fuel used, the HC emissions decrease significantly, while the CO and NOx emissions increase with the increase of MMT content in the test fuels. There was a measurable effect on PM emissions by the introduction of the MMT additive gasoline fuels. The total particulate mass and number concentrations significantly increase with the increase of the MMT content in the test fuels. At low and medium loads, there is little change in geometrical mean diameter of the particles, while it would become larger when the tested engine operated on the high engine condition.

Influence of aqueous environment on agglomeration and dissolution of thiol-functionalised mesoporous silica-coated magnetite nanoparticles.

The purpose of the present research work is to investigate the stability and dissolution of magnetite (Fe3O4) nanoparticles (NPs) and thiol-functionalised mesoporous silica-coated magnetite NPs (TF-SCMNPs). The state of NPs in an aqueous environment was investigated under different pH conditions. Changes in the NPs' mean diameter due to aggregation were measured over a specific time. The effects of contact time and pH on the dissolution of NPs were also investigated. In order to avoid possible aggregation, Fe3O4 NPs were coated with silica and functionalised further with thiol organic groups. These methods imparted excellent stability to magnetite NPs in an aqueous medium over a wide range of pH values with reasonable hydrodynamic size. The organic group bound magnetite NPs allowed these particles to circulate over a long time in the aqueous system, and particle aggregation and sedimentation did not occur. The trend of decreasing zeta potential was observed after grafting thiol onto the surface of the SCMNPs. The results also revealed that silica exhibited a noteworthy efficient in eliminating the pH dependence and enhancing the NP stability of SCMNPs and SH-SCMNPs in aqueous medium. On the other hand, the dissolution of Fe3O4 NPs was found to be detrimental at pH 2.0 and 4.0 or had a long contact time.

The short‐term effect of flavonoid‐rich dark chocolate on retinal vessel diameter in glaucoma patients and age‐matched controls

To investigate the effect of flavonoid-rich dark chocolate and non-flavonoid-rich white chocolate on retinal vessel diameter in glaucoma patients and age-matched controls. Thirty glaucoma patients and 30 age-matched subjects were assigned to dark or white chocolate by randomization with forced equal distribution. The number in each of the four groups was 15. Measured parameters included systemic blood pressure (BP), blood glucose levels, static retinal vessel analysis, as measured by central retinal artery equivalent (CRAE) (which relates to the diameter of the central retinal artery), central retinal vein equivalent (CRVE) (which relates to the diameter of central retinal vein) and the arterio-venous ratio (AVR), which represents the CRAE/CRVE ratio, dynamic retinal vessel analysis as measured by the change in vessel diameter in response to flicker light stimulation. Three recording cycles from each were averaged. Blood pressure parameters (systolic BP, diastolic BP and pulse), IOP and blood glucose levels did not differ significantly between both groups before and after consumption of white or dark chocolate. Static vessel analysis did not show any significant changes in CRAE, CRVE or AVR before and after dark or white chocolate in both groups (p > 0.05). Mean dilatation of the venules in the control group was 3.2 ± 0.9 % before dark chocolate and 4.2 ± 1.4 % after dark chocolate intake, which was statistically significantly different (p = 0.01). Mean dilatation of the arterioles in the control group was 2.8 ± 1.8 % before dark chocolate and 3.5 ± 1.8 % after dark chocolate intake with a trend to statistical significance (p = 0.14), but not reaching the significance level. Mean diameter changes in the glaucoma group did not show any significant differences after dark chocolate consumption. The present study showed a significant improvement of venous vasodilatation 2 hr after dark chocolate intake in the control group, but not in the glaucoma group. This effect might be indicative of an increased bioavailability of nitric oxide (NO) after dark chocolate consumption. The lack of finding a significant venous response after dark chocolate in the glaucoma group might be related to the already impaired endothelial function in these patients.

Engineering properties and microstructural characteristics of cement-stabilized zinc-contaminated kaolin

This paper presents details of a study that deals with determination of engineering properties, identification of phases of major hydration products, and microstructural characteristics of a zinc-contaminated (referred to as Zn-contaminated in this paper) kaolin clay when it is stabilized by a cement additive. Investigations were carried out with respect to the effect of the level of zinc (Zn) concentration on the overall soil properties including Atterberg limits, water content, pH, stress–strain characteristics, unconfined compressive strength, and secant modulus. In addition, X-ray diffraction, scanning electron microscopy, and mercury intrusion porosimetry studies were conducted to understand the mechanisms controlling the changes in engineering properties of the stabilized kaolin clay. The study reveals that the level of Zn concentration has a considerable influence on the engineering properties, phases of hydration products formed, and microstructural characteristics of the stabilized kaolin clay. These changes are attributed to the retardant effect of Zn on the hydration and pozzolanic reactions, which in turn alters the phases of hydration products and cementation structure – bonding of the soils. Theoretical simulation of the pore-size distribution curves demonstrates that the cement-stabilized kaolin exhibits bimodal type when the Zn concentration is less than 2%, whereas it displays unimodal type when the Zn concentration is 2%. With an increase in the Zn concentration, the characteristics of the interaggregate pores in terms of volume and mean diameter change considerably, whereas those of intra-aggregate pores remain nearly unchanged.

The effects of morphology on the thermal reduction of nonstoichiometric ceria

A numerical heat and mass transfer model is used to study the effects of the morphological features of a porous medium composed of ceria when it is placed in a cavity and exposed to high-flux solar irradiation to drive a nonstoichiometric reduction. The morphological features are described by the porosity and pore-level Sauter mean diameter. For porosities of 0.60, 0.75, and 0.90, the rate of oxygen production and the efficiency of solar-to-chemical energy conversion increase monotonically as the Sauter mean diameter is decreased from 1000 to 30µm. For a porosity of 0.90, these performance metrics continue to increase down to 10µm. The primary effect of the changes in porosity and Sauter mean diameter are through their influence on the permeability and the extinction coefficient of the medium. For appropriately selected time duration, an energy conversion efficiency of 10.9% is achieved with a Sauter mean diameter of 10µm and a porosity of 0.90.

Effect of Isopropanolic Cimicifuga racemosa Extract on Uterine Fibroids in Comparison with Tibolone among Patients of a Recent Randomized, Double Blind, Parallel‐Controlled Study in Chinese Women with Menopausal Symptoms

Objective. Effect of isopropanolic Cimicifuga racemosa extract (iCR) on uterine fibroid size compared with tibolone. Method. The randomized, double-blind, controlled study in China enrolled 244 patients aged 40–60 years with menopausal symptoms (Kupperman Menopause Index ≥ 15). The participants were treated with either iCR of 40 mg crude drug/day (N = 122) or tibolone 2.5 mg/day (N = 122) orally for 3 months in 2004. Now, we investigated the subset of all women (N = 62) with at least one uterine fibroid at onset of treatment for the effect of iCR (N = 34) on fibroid size compared with tibolone (N = 28) by transvaginal ultrasonography. Results. The median myoma volume decreased upon iCR by as much as −30% (P = 0.016) but increased upon tibolone by +4.7%. The percentage of volume change, mean diameter change and geometric mean diameter change of the iCR group compared to tibolone were statistically significant (P = 0.016, 0.021, 0.016 respectively). Conclusion. Our results suggest that iCR (Remifemin) is a valid herbal medicinal product in patients with uterine myomas as it provides adequate relief from menopausal symptoms and inhibits growth of the myomas in contrast to tibolone.

Calf contouring with endoscopic fascial release, calf implant, and structural fat grafting.

Background:Curved lower legs cause psychological stress for women. In evaluating the shape, if thickness is the main contributing factor of leg aesthetic, then lipoplasty or calf reducing procedures will be the option. If the legs are slender and have no muscle hypertrophy but still have some indentation or bulges on both sides and lack an aesthetic shape what will be the options? The answer to the question is discussed in detail in this article.Methods:Twenty-two patients, operated over a period of 5 years from 2007 to 2012, were included in the study. A novel technique has been introduced. This method requires release of fascia covering muscles of the inner leg bulge via endoscopic approach and simultaneous calf augmentation with calf implant, liposuction, and structural fat grafting to optimize the results.Results:Patients were followed on a regular basis with a mean follow-up of 31 months. The procedure was well tolerated with minimal discomfort during the postoperative period. Increase in diameter of proximal and distal lower legs was measured at least 6 months after surgery. Mean diameter change of proximal lower legs was 2.16 cm and 1.77 cm in distal lower legs.Conclusions:A novel endoscopic approach for lower leg contouring is discussed. Endoscopic fasciotomy technique with calf implant and structural fat grafting for improved lower leg aesthetics is a simple, effective, reliable, and predictable technique for calf contouring.

A new approach to modeling stand-level dynamics based on informed random walks: influence of bandwidth and sample size

A new stand-level dynamics model based on observed stand growth trajectories is presented. This stand-level dynamics model uses the trajectories of observed plots through Reineke’s quadratic mean diameter-density space to predict the change in quadratic mean diameter, ingrowth and mortality over time. The model uses the collection of observed trajectories as a probability distribution that is used to guide an informed random walk. An imputation model is used to select k nearest neighbors (bandwidth) which are then used to build joint kernel distributions. From these kernel distributions, m random samples (sample intensity) are averaged to predict the change in quadratic mean diameter, ingrowth and mortality. All levels of k tested (10, 20, 30) performed well as long as sampling intensity was above 1. Variability in predictions was reduced at sampling intensities above 1, but no significant differences were visible among sampling intensities 5 and above.

Mercerization Treatment Conditions Effects on Kenaf Fiber Bundles Mean Diameter Variability

The interest in utilizing natural fiber as reinforce in polymer composites has increased in recent years due to their advantages like availability, cheap, renewable, lightweight, and biodegradable. However, the main challenge of natural fiber to be used as reinforcement in polymer is their hydrophobic nature. One of the solutions is via chemical modification like mercerization treatment. In this study, the effect of alkali concentrations at 2 and 10 w/v %; and soaking temperature at 30°C and 80°C on a kenaf fiber bundles mean diameter was investigated. Untreated kenaf fiber was used as a control unit. Kenaf fiber diameter was measured using a Leica video analyzer. Microstructure change of kenaf fiber before and after mercerization treatment conditions was identified using JOEL scanning electron microscopy (SEM). Finally, an interaction of alkali treatment conditions on kenaf fiber bundles mean diameter value was statistically analyzed using a commercially available statistical software package. The results showed that kenaf fiber bundle mean diameter was reduced by 30.12% to 42.92% after mercerization treatment. From analysis of variance, the main effect of alkali concentration value was 6.075 and the temperature value was 1.135. The main effect plots reveal that alkali concentration had a higher impact on mean diameter changes compared to soaking temperature factor.

Preparation and stability study of norfloxacin-loaded solid lipid nanoparticle suspensions

This work aims to develop norfloxacin-loaded solid lipid nanoparticle (NFX-SLN) suspensions as a novel formulation. NFX-SLN suspensions were prepared by hot homogenization and ultrasonic technique. The stability of the suspensions was studied after stored at 4°C and room temperature from 3 to 9 months. The physicochemical characteristics of the NFX-SLN, in vitro release patterns, in vitro antibacterial activity and in vivo therapeutic efficacy in mice after infection with Escherichia coli were conducted and used to evaluate the stability of the suspension. The results showed that the mean diameter (MD), polydispersity index (PDI), zeta potential (ZP) and loading capacity (LC) of nanoparticles were 250±5nm, 0.256±0.065, −31.1±1.85mV and 9.63±0.16%, respectively. After 9 months of storage at 4°C, the NFX-SLN showed no significant changes in MD, PDI and LC except a miner change in ZP. Moreover, the stored suspension displayed same sustained release patterns and in vitro sustained bactericidal activities as that of the fresh preparation. In vivo therapeutic results revealed that the stored suspension had similar enhanced therapeutic efficacy as the fresh preparation compared with native drug. At room temperature the formulation was stable for 3 months, but the LC, ZP and PDI changed and the suspension displayed accelerated release and weakened in vitro antibacterial activity after 6 months. These results demonstrate that NFX-SLN suspensions could be a promising formulation for enhanced pharmacological activity of norfloxacin and were stable at 4°C and less stable at room temperature.

Research of the microstructure and precipitation strengthening in a high-temperature Fe–Ni superalloy

The paper describes the relationships between the kinetics of precipitation and growth of the intermetallic phase γ′ - Ni3(Al,Ti) and the strengthening magnitude obtained in a high-temperature Fe–Ni superalloy of the A-286 type. In order to accomplish the goal of the study, the author used the LSW coagulation theory and Brown and Ham's conventional analysis of strengthening by ordered particles. The samples were subjected to a solution heat treatment at 980°C/2h/water and then aged at 715, 750 and 780°C, with holding times 0.5-500 h. The heat-treated samples were subjected to structural analyses (TEM, X-ray diffraction) and analyses of mechanical properties (hardness test, static tensile test). Direct measurements on the electron micrographs allowed to calculate the structural parameters of the γ′ phase, i.e. mean diameter, volume fraction and mean distance between particles. In accordance with the LSW theory, linear dependencies of changes in mean diameter as a function of ageing time (t1/3) were elaborated and the activation energy (E) of the γ′ phase coagulation process was determined. The author carried out analyses of strengthening and flow stress (Δτ0) increases as a function of the particle size of the γ′ phase and determined the value of the antiphase boundary energy (yapb) for the analyzed Fe–Ni alloy. It was found that the value of APB energy of phase γ′ depended significantly on the alloy ageing temperature. Such a dependence of the quantity yapb on the ageing temperature for the investigated alloy was explained by an increase in the degree of internal arrangement of phase γ′ and by increasing sizes of ordered domains as a result of coalescence.

Analysis of Dissolved-Gas Atomization: Supercritical CO2 Dissolved in Water

Supercritical dissolved-gas atomization is an atomization process in which carbon dioxide at temperature and pressure above its critical point is used as the atomizing gas. The spray characteristics in terms of droplets size and distribution have been experimentally studied using a laser diffraction method based on a Malvern apparatus. The main parameter that influences the droplets size is the gas-to-liquid mass ratio (GLR); the injection pressure in the range of 7.4−13 MPa has a minor effect. Upon variation of the GLR from 0.5 to 3, the droplet mean diameter changes from about 8.0 to 2.0 μm; very narrow droplet size distributions are also produced. From the point of view of the atomization mechanism, the mean droplet diameter is mainly influenced by the sudden release of the gas dissolved in the liquid. The overall analysis of the experimental data confirms that dissolved-gas atomization allows for the formation of micrometric droplets that can produce precipitates with controlled sizes and distributions that are useful in several fine-particles production processes.

Study of the pilot production process of long-circulating and pH-sensitive liposomes containing cisplatin

Long-circulating and pH-sensitive liposomes, containing cisplatin (SpHL-CDDP), have been developed as an alternative aimed at avoiding severe side effects as well as the appearance of resistance, which can limit the use of free cisplatin. However, physical (i.e., aggregation/fusion) and chemical instabilities limit the use of these drug carriers as pharmaceutical products. The preparation of freeze-dried pharmaceuticals has proven to be a successful strategy implemented to improve the stability of these formulations. In addition, the development of an economically feasible, reproducible process of liposome production, on a large scale, has also become necessary. A pilot production process, using three stages (i.e., reverse-phase evaporation, homogenization under high pressure, and ultrafiltration), was used to prepare SpHL-CDDP. The optimization of factors related to the homonogenization under high pressure (i.e., pressure and number of cycles), ultrafiltration (i.e., number of cycles), and storage stability at 4°C were assessed by means of particle size, zeta potential, and encapsulation percentage. A 500-bar pressure and 9 cycles were adopted as measures for the production of SpHL-CDDP, which presented a mean diameter of 99.0 ± 3.9 nm and an encapsulation percentage of 12.9 ± 2.3. The use of trehalose as a cryoprotectant was investigated, regarding its effective ability to control the vesicle diameter and retain encapsulated CDDP after the freeze-drying/rehydration step. After 135 days of storage, freeze-dried or liquid SpHL-CDDP showed no significant change in mean diameter. However, the freeze-dried SpHL-CDDP proved to be more efficient, in terms of CDDP retention, than did the liposomal liquid dispersion.

Double Cross-linked Chitosan—Gelatin Particulate Systems for Ophthalmic Applications

Gelatin/chitosan particles suitable for application in ocular drug administration were prepared by a two-step cross-linking process performed in an emulsion-phase separation system. The particles were characterized by scanning electron microscopy and laser diffractometry, and the diameters were 0.202—4.596 µm. The microparticles pH-dependent behavior was monitored by their mean diameter changes in aqueous environment. Adrenalin was drug used to study loading and release characteristics. The prepared particles were nontoxic, with the DL50 values of 6.9—8.19 g/kg body mass. The in vivo biocompatibility tests consisted of subcutaneous administration of a microparticle suspension in physiological serum followed by morpho histological analysis of the implantation site. The in vivo adrenalin ocular delivery was tested on both animals and a voluntary human patient to determine the adrenalin action and by tears. The particles showed good adherent properties without irritation to the patient; adrenalin was released cleared the ocular congestion.

Dynamics of the Aorta Before and After Endovascular Aneurysm Repair: A Systematic Review

An overview of the knowledge of thoracic (TAA), and abdominal aortic aneurysm (AAA) dynamics, before and after endovascular repair, is given. Medline, EMBASE and the Cochrane database were searched for relevant articles. After inclusion and exclusion, 25 relevant articles reporting on aneurysm dynamics remained, allowing for comparison. Results provided in the included studies were assumed (statistically) significant if they were larger than the repeatability of the used method. The sample size of dynamic studies is limited and translational studies are missing. Magnetic resonance angiography (MRA) and computed tomographic angiography (CTA) were shown to have lower inter-observer variabilities than ultrasonography (US). The distension of several relevant stent-graft-landing zones during the cardiac cycle in both the abdominal and thoracic aorta are significant (mean diameter change of the AAA neck in the included studies ranged from 0.9 mm to 2.4 mm; mean area change of the thoracic aorta ranged from 4.8% to 12.7% at various levels). This distension remained preserved after stent-graft placement. Preoperatively, the renal arteries displace per heartbeat. Significant movement of the aorta in the anteroposterior (AP) and lateral direction, during the cardiac cycle, was observed. The aorta exhibits a wide variety of morphologic changes throughout the cardiac cycle. CTA and MRA are reliable modalities to investigate aortic shape changes during the cardiac cycle. Significant changes per heartbeat are reported in the AAA neck and thoracic aorta. The renal artery displaces per heartbeat. The clinical relevance of dynamic imaging has not been proven yet, but dynamic changes of the aorta have to be taken into account in stent-graft selection and future stent-graft design.

Changes in Lipid-Encapsulated Microbubble Population During Continuous Infusion and Methods to Maintain Consistency

Stabilized microbubbles are used as ultrasound contrast agents. These micron-sized gas capsules are injected into the bloodstream to provide contrast enhancement during ultrasound imaging. Some contrast imaging strategies, such as destruction-reperfusion, require a continuous injection of microbubbles over several minutes. Most quantitative imaging strategies rely on the ability to administer a consistent dose of contrast agent. Because of the buoyancy of these gas-filled agents, their spatial distribution within a syringe changes over time. The population of microbubbles that is pumped from a horizontal syringe outlet differs from initial population as the microbubbles float to the syringe top. In this manuscript, we study the changes in the population of a contrast agent that is pumped from a syringe caused by microbubble floatation. Results are presented in terms of change in concentration and change in mean diameter, as a function of time, suspension medium and syringe diameter. Data illustrate that the distribution of contrast agents injected from a syringe changes in both concentration and mean diameter over several minutes without mixing. We discuss the application of a mixing system and viscosity agents to keep the contrast solution more evenly distributed in a syringe. These results are significant for researchers using microbubble contrast agents in continuous-infusion applications where it is important to maintain consistent contrast agent delivery rate, or in situations where the injection syringe cannot be mixed immediately before administration. (E-mail: padayton@bme.unc.edu)

Aqueous Extraction of Oil Bodies from Maize Germ (Zea mays) and Characterization of the Resulting Natural Oil-in-Water Emulsion

Oil bodies in the form of an adequately dispersed suspension were extracted from maize germ by applying aqueous extraction. The effect on the yield of oil body extraction of parameters, such as pH of aqueous medium, state of germ comminution, and number of successive extraction steps applied, was evaluated, indicating that an extraction yield as high as 95% could be reached when a finely comminuted germ material is extracted 3 times under alkaline conditions. The extracted oil body suspension was coagulated by pH manipulation, and the resulting cream, consisting of intact oil bodies, was studied with respect to protein composition, particle size distribution, and oil body zeta potential. Changes in particle mean diameter resulting during oil body cream storage as well as the creaming behavior of emulsions prepared by cream dilution with water were also investigated. The findings are discussed in terms of the presence at the oil body surface of an adsorbed mixed layer made up of phospholipids, oleosins, and extraneous germ proteins that determine the physical stability of oil droplets upon long-term storage.

Distensibility of Forearm Veins in Haemodialysis Patients on Duplex Ultrasound Testing Using Three Provocation Methods

It is well-known that vasodilatator function is affected in patients with renal failure. We hypothesized impaired venous forearm distensibility in haemodialysis patients. The purpose of this study was to investigate which provocation method generated 'maximal' venous distensibility in the forearm of haemodialysis patients compared to healthy volunteers by using duplex ultrasound. The study group consisted of haemodialysis patients (n=30) and healthy volunteers (n=30). In each participant ultrasound measurements of the venous diameter were performed by using 3 different provocation methods. The applied provocation methods were: 1) hydrostatic pressure, 2) venous congestion and 3) hydrostatic pressure and warmth. Significance of differences in mean diameter changes within the groups was assessed with the paired t-test. Significance of differences in mean diameter changes between the groups was compared by using multivariate regression analysis. In haemodialysis patients, the increase in mean diameter after the different methods was: 29% after methods 2 versus 1, 23% after methods 3 versus 2 and 59% after methods 3 versus 1. In healthy volunteers, the mean diameter increase was: 27% after methods 2 versus 1, 29% after methods 3 versus 2 and 64% after methods 3 versus 1. The greatest increase in the mean internal venous diameter among the haemodialysis patients and the healthy volunteers was after the provocation method which combined hydrostatic pressure with warmth (mean difference: 1mm, 95% CI: .57, 1.36; P<.001 and mean difference: 1.4mm, 95% CI: .88, 1.78; P<.001, respectively). After adjustment for the baseline variables, both groups demonstrated a non-significant mean diameter difference for each of the provocation methods. Hydrostatic pressure combined with warmth generates the greatest venous distensibility in the lower arm in haemodialysis patients in a sitting position and is not significantly different compared to healthy volunteers. Without the superior provocation method, venous diameters of haemodialysis patients can be assessed as false-negatives yielding that a primary radio cephalic arteriovenous fistula (RCAVF) at wrist level (the first choice) in these patients will be withheld.

Emission reduction from diesel engine using fumigation methanol and diesel oxidation catalyst

This study is aimed to investigate the combined application of fumigation methanol and a diesel oxidation catalyst for reducing emissions of an in-use diesel engine. Experiments were performed on a 4-cylinder naturally-aspirated direct-injection diesel engine operating at a constant speed of 1800 rev/min for five engine loads. The experimental results show that at low engine loads, the brake thermal efficiency decreases with increase in fumigation methanol; but at high loads, it slightly increases with increase in fumigation methanol. The fumigation method results in a significant increase in hydrocarbon (HC), carbon monoxide (CO), and nitrogen dioxide (NO 2) emissions, but decrease in nitrogen oxides (NO x), smoke opacity and the particulate mass concentration. For the submicron particles, the total number of particles decreases. In all cases, there is little change in geometrical mean diameter of the particles. After catalytic conversion, the HC, CO, NO 2, particulate mass and particulate number concentrations were significantly reduced at medium to high engine loads; while the geometrical mean diameter of the particles becomes larger. Thus, the combined use of fumigation methanol and diesel oxidation catalyst leads to a reduction of HC, CO, NO x, particulate mass and particulate number concentrations at medium to high engine loads.