Tunneled-cuffed catheter implanted into the accessory hemiazygos vein because of occlusion of the left innominate vein

Hemodialyzed patients are at risk of multiple catheterizations. Nephrologists performing such procedures need to be familiar with congenital and acquired vascular abnormalities. We describe a successful insertion and use of a cuffed-tunneled catheter in a patient with unusual anatomy of the central venous system. Computed tomography angiography revealed thrombosis of the right subclavian vein and bilateral occlusion of innominate veins. The left internal jugular and subclavian veins joined to form a large vessel that drained through the accessory hemiazygos and azygos veins into the superior vena cava. The catheter was implanted through the left internal jugular vein into the accessory hemiazygos vein. The presented case demonstrates that the catheter can be implanted into distended collateral, especially when no other location is possible.     

Distribution of the displacement sequence of an orientation preserving circle homeomorphism

In some applications not only the knowledge of the behaviour of trajectories of a map is important, but also their displacements. We describe in detail the distribution of elements of the displacement sequence along a trajectory of an orientation preserving circle homeomorphism ? with irrational rotation number ?(?). The values of displacement are dense in a set which depends on the map γ (semi-)conjugating ? with the rotation by ?(?) and which is the support of the displacement distribution. We provide an effective formula for the density of this distribution if γ is a C¹-diffeomorphism. Moreover, we show approximation of the displacement distribution by sample displacements measured for any other circle homeomorphism sufficiently close to the initial homeomorphism ?, which constitutes a rigorous proof of numerical results seen in certain integrate-and-fire models.     

Use of the subcutaneous venous network of the forearm to create an arteriovenous fistula

The reconstruction of vascular access in patients with kidney allograft failure is a challenging problem. A case of a 62‐year‐old man with transplanted kidney insufficiency is described. The patient was initially dialyzed with a wrist radial‐cephalic arteriovenous fistula. In the post‐transplantation period, the enormously dilated venous part of the anastomosis was ligated and the part of the vein suspected of being the source of bacteremia was excised. The man was referred to our department due to kidney allograft failure for vascular access creation. During preoperative assessment, we unexpectedly found a soft thrill on the forearm. Doppler ultrasound confirmed fistula patency, although the blood supply was not sufficient to perform dialysis. Angiography showed the blood flow from the radial artery to the cephalic vein, through a complicated vessel system consisting of inter alia a dilated vein of the subcutaneous venous network. We successfully used this vein as the vascular access outflow for fistula recreation. In conclusion, making use of veins of the subcutaneous venous network of the forearm for creation of a native fistula should be considered in selected cases.     

Urgent hemodialysis with the use of peripheral veins to avoid catheter insertion

Urgent hemodialysis (HD) in patients with uremia is usually performed using a central vein catheter unless an arteriovenous fistula (AVF) was created in the predialysis period. We present a unique approach, in a patient in whom the first two HD sessions were conducted without implantation of a catheter or AVF. The perfectly developed peripheral veins of a professional bodybuilder served as vascular access allowing catheter insertion to be avoided. The aim of this short case report is to recall a forgotten method for performing urgent HD in patients without a fistula, but with suitably enlarged superficial veins.     

Detection of irradiation treatment in dried mushrooms by photostimulated luminescence,EPR spectroscopy and thermoluminescence measurements

Detection of the irradiation treatment of nine species of dried mushrooms commercially available employing photostimulated luminescence (PSL), electron paramagnetic resonance spectroscopy (EPR/ESR) and thermoluminescence (TL) is described. PSL is adaptable to six to seven species shortly after irradiation, but the PSL signal decays with storage and may render detection impossible. After 4 months of storage, six species could still be well identified by PSL if the radiation dose was higher than 5 kGy. EPR spectroscopy enabled detection with five to six species, both cellulose and crystalline sugar-like radicals being observed. For some mushrooms, hat or leg parts showed a different response and some lots could not be identified at all. TL - although being more cumbersome - allowed unequivocal identification of all species of investigated mushrooms. It is concluded that dried mushrooms exposed to ionising radiation can be successfully detected by at least one of the analytical methods investigated.     

Automated analyser for monitoring trace amounts of volatile chloro-organic compounds in recirculated industrial water

An automated analyser of volatile chloro-organic compounds in water was constructed and tested using standard mixtures of dichloromethane and dichloroethane. It was based on continuous, countercurrent gas stripping of the liquid sample followed by periodic trapping of the analytes on two traps alternately connected to the bubbler outlet, and thermal desorption. When one trap performed adsorption, the other underwent desorption and cooling. Analytes were detected by an ECD detector. Integration, calibration, calculations and overall operating cycle control was performed by a microcomputer. The instrument guarantees a 0.02 ppm Cl (w/w) detection limit, a 0-2 ppm detection range and 2 months of autonomous operation. Results are reported every 13 min.     

Two-dimensional modelling of deposits formation on platen superheaters in pulverized coal boilers

The 1D modeling of deposits formation is not able to describe properly the gas and particles flow in the vicinity of heat transfer tubes in boilers. Especially, the recirculation zones in the down-stream side of tubes are not possible to reproduce by the 1D models. Known applications of the CFD codes to deposition modelling were able to reproduce only the rate of particles deposition on surfaces, while for practical reasons the most important information is the shape and size of deposits, because it enables prediction of heat transfer abatement with boiler operation time. Paper presents 2D modelling of deposits on platen superheaters in pulverized coal boilers. Particularly, the observed in industrial boilers bridging of the tubes spacing was reproduced by the model in which the particle size dependence of the ash sticking probability was proposed. It has been demonstrated that the ash particles size play important role in the deposits growth mechanism.     

Characterization of Acidity and Porosity of Zeolite Catalysts by the Equilibrated Thermodesorption of n-Hexane and n-Nonane

Thermodesorption of n-hexane and n-nonane from the acidic and non-acidic zeolites ZSM-5 and Y was studied by means of the thermogravimetric temperature programmed equilibrated desorption (TPED) and quasi-equilibrated temperature programmed desorption and adsorption (QE-TPDA). Micropore volumes determined from the adsorption capacity of n-hexane were close to those determined by N₂ adsorption. Content and strength of acid sites in the acidic zeolites estimated by fitting the Arrhenius equation to the high temperature parts of QE-TPDA profiles of n-hexane attributed to its cracking were in agreement with their acidity characteristics obtained by IR spectroscopy of chemisorbed pyridine. The mesopore volume was determined from the QE-TPDA profiles of n-nonane. Coking observed only for QE-TPDA of n-nonane on H-USY zeolite resulted in blocking the micropores without affecting the mesopores.     

Porosity and surface properties of mesoporous silicas and their carbon replicas investigated with quasi-equlibrated thermodesorption of <Emphasis Type="Italic">n</Emphasis>-hexane and <Emphasis Type="Italic">n</Emphasis>-nonane

Adsorption of n-hexane and n-nonane on mesoporous micelle-templated silicas (SBA-15 and MLV—multilayer vesicle) and on their carbon replicas (CMK-3 and OCM—onion-like carbonaceous material) was studied by means of quasi-equilibrated thermodesorption technique, utilising a standard TPD setup with a chromatographic detector. Analysis of n-hexane adsorption isobars, determined from the thermodesorption profiles, revealed substantial heterogeneity of the adsorption sites present in the carbonaceous materials. The pore size distributions calculated from the thermodesorption profiles of n-nonane for both siliceous and carbonaceous materials were in agreement with those obtained from the low-temperature nitrogen adsorption isotherms. They confirm an uniform structure of mesopores in SBA-15, CMK-3 and OCM as well as a more complex structure of mesopores in the MLV materials.