Intra-arterial computed tomography angiography with ultra-low volume of iodine contrast and stent implantation in transplant renal artery stenosis in terms of contrast-induced kidney injury : a preliminary report

Purpose: Traditional digital subtraction angiography is still regarded as the gold standard in the diagnostics of transplant renal artery stenosis (TRAS). However, this procedure requires a high volume of iodine contrast medium for optimal visualisation of the renal artery. The aim of this study was to analyse both the usefulness and the safety of intra-arterial computed tomography angiography (IA-CTA) with ultra-low-volume iodine contrast administration in the diagnostic and therapeutic management of TRAS in patients with impaired renal transplant function. Material and methods: Thirty-three patients with a suspicion of TRAS based on Doppler-ultrasound and clinical setting underwent IA-CTA with ultra-low iodine contrast volume. A special, author-elaborated CTA protocol was used. The volume of 8-18 ml of diluted iodine contrast medium was administered through a catheter with the tip placed 2 cm below the aortic bifurcation. Results: In six patients the CTA examinations revealed TRAS in three configurations: in the anastomosis, in the trunk (critical and high-grade), or in both sections. Stenoses were treated with primary stenting obtaining favourable anatomical outcome. No intervention-related complications were observed. No contrast-induced acute kidney injury was diagnosed in this study. Mean serum creatinine concentration was 2.93 ± 0.89 mg/dl at the baseline and 2.89 ± 1.73 mg/dl and 2.17 ± 0.51 mg/dl after three and seven days from IA-CTA, respectively. Conclusions: Intra-arterial CTA with ultra-low volume of iodine contrast seems to be a safe and reliable diagnostic tool to detect and assess TRAS in the aspect of stent implantation. Application of this imaging modality eliminates the need for a high volume of iodine contrast and thus does not adversely influence renal transplant function

Design and Evaluation of the Compact and Autonomous Energy Subsystem of a Wave Energy Converter

This paper presents the results of the design process focused on the development of the energy subsystem (ES) of a wave energy converter (WEC). The ES is an important electrical part that significantly affects the energy reliability and energy efficiency of the entire WEC device. The designed ES was intended for compact WECs powering IoT network devices working in the distributed grid. The developed ES is an electronic circuit consisting of three cooperating subsystems used for energy conversion, energy storage, and energy management. The energy conversion subsystem was implemented as a set of single-phase bridge rectifiers. The energy storage subsystem was a battery-less implementation based on the capacitors. The energy management subsystem was implemented as a supervisory circuit and boost converter assembly. The designed ES was verified using the physical experiment method. The model experiment reflected the operation of the designed ES with a piezoelectric PZT-based WEC. The experimental results showed a 41.5% surplus of the energy supplied by ES over the energy demanded by the considered load at a duty cycle of ca. 6 min—37.2 mJ over 26.3 mJ, respectively. The obtained results have been evaluated and discussed. The results confirmed the designed ES as a convenient solution, which makes a significant contribution to the compact WECs that can be applied among others to a distributed grid of autonomous IoT network devices powered by free and renewable energy of sea waves. Finally, it will also enable sustainable development of mobile and wireless communication in those maritime areas where other forms of renewable energy may not be available

Fuzzy Control of Waves Generation in a Towing Tank

This paper presents the results of research related to the transformation of electrical energy into potential and kinetic energy of waves generated on the water surface. The waves are generated to model the environmental conditions for the needs of the model tests. The model tests are performed on model-scale objects to predict the features of full-scale maritime objects. It is done to improve human safety and the survivability of constructions. Electrical energy is transformed into the energy of the water waves using a wave maker. The wave maker considered is a facility with an electrohydraulic drive and an actuator submerged into the water. The actuator movement results in the waves being mechanically-generated in accordance with the wave maker theory. The study aimed to investigate the advantage of the newly implemented fuzzy-logic controller over the hitherto cascading proportional-integral controllers of the wave maker actuator. The research was focused on experimental investigation of the transformation process outcomes harvested under the fuzzy-logic controller, versus the cascading proportional-integral controllers. The waves were generated and measured in the real towing tank, located in the Maritime Advanced Research Centre (CTO S.A.). The investigation confirmed the advantage of the fuzzy-logic controller. It provides more accurate transformation of energy into the desired form of the water waves of specified parameters—frequency and amplitude—and more flat amplitude-frequency characteristic of the transformation process

Open-Phase Fault Detection Method for Sensorless Five-Phase Induction Motor Drives with an Inverter Output Filter

The paper presents the sensorless five-phase induction motor drive implementation with an inverter output filter with third harmonic injection. For the sensorless operation, the required observers are presented for the first and third harmonics with consideration of the inverter output filter. Moreover, the interaction of the observers and the control system is capable to handle a deactivation of one or two phases, which improves the reliability of the complete drive system. A new idea of online open-phase fault detection is presented based on the frequency analysis of the estimated observer variables. The test setup, fault operation capabilities and an experimental verification of the proposed fault detection method are presented in the paper

Evaluation of the effectiveness of partial splenic endovascular embolization in patients with refractory thrombocytopaenia

Purpose: Partial splenic endovascular embolization (PSEE) could be an option for patients with thrombocytopaenia (TCP). We selected a group of 22 patients diagnosed with refractory TCP to undergo PSEE, and we followed them for detailed analysis. Material and methods: Twenty-two patients aged 27-75 years (mean 46.5 ± 3.5 years) underwent PSEE, and 5 participants underwent a second PSEE due to the lack of effectiveness after the first procedure. A total of 27 PSEEs were performed. A semi-quantitative scale was used to assess the severity of the post-embolization syndrome. The percentage of spleen parenchyma excluded from circulation was 30-70%. We used the mixture of Histoacryl N-butyl cyanoacrylate glue and Lipiodol in 10 cases, spirals in 10 cases, and polyvinyl alcohol in 7 cases, for the embolization. Results: The mean value of platelet count (PLT) before procedure increased from 22.0 ± 15.0 to 87.7 ± 67.9 (p < 0.05) in a mean period of 194 days. In 2 cases severe post-embolization syndrome was observed. Closure less than 50% of the spleen circulation was associated with poorly expressed post-embolization symptoms. Serious complications occurred in 1 patient (3.5%). A strong positive correlation (r = 0.8, p < 0.05) was found between C-reactive protein (CRP) and the severity of post-embolization syndrome. Increased symptoms of post-embolization syndrome were also associated with a significant increase in hospitalization time – 27.0 vs. 7.2 days (r = 0.66, p < 0.05). Conclusions: Partial endovascular embolization of the spleen (PSEE) may be a valuable therapeutic option for patients with refractory TCP. PSEE is a safe method with a low complication rate

Intraarterial CT angiography using ultra low volume of iodine contrast : own experiences

BACKGROUND: High volume of intravenous contrast in CT-angiography may result in contrast-induced nephropathy. Intraarterial ultra-low volume of contrast medium results in its satisfactory blood concentration with potentially good image quality. The first main purpose was to assess the influence of the method on function of transplanted kidney in patients with impaired graft function. The second main purpose of the study was to evaluate the usefulness of this method for detection of gastrointestinal and head-and-neck haemorrhages. MATERIAL AND METHODS: Between 2010 and 2013 intraarterial CT-angiography was performed in 56 patients, including 28 with chronic kidney disease (CKD). There were three main subgroups: 18 patients after kidney transplantation, 10 patients with gastrointestinal hemorrhage, 8 patients with head-and-neck hemorrhage. Contralateral or ipsilateral inguinal arterial approach was performed. The 4-French vascular sheaths and 4F-catheters were introduced under fluoroscopy. Intraarterial CT was performed using 64-slice scanner. The scanning protocol was as follows: slice thickness 0.625 mm, pitch 1.3, gantry rotation 0.6 sec., scanning delay 1-2 sec. The extent of the study was established on the basis of scout image. In patients with CKD 6-8 mL of Iodixanol (320 mg/mL) diluted with saline to 18-24 mL was administered at a speed of 4-5 mL/s. RESULTS: Vasculature was properly visualized in all patients. In patients with impaired renal function creatinine/eGFR levels remained stable in all but one case. Traditional arteriography failed and CT-angiography demonstrated the site of bleeding in 3 of 10 patients with symptoms of gastrointestinal bleeding (30%). In 8 patients with head-and-neck bleeding CT-angiography did not prove beneficial when compared to traditional arteriography. CONCLUSIONS: 1. Ultra-low contrast intraarterial CT-angiography does not deteriorate the function of transplanted kidneys in patients with impaired graft function. 2. 3D reconstructions allow for excellent visualization of vascular anatomy of renal transplants. 3. Intraarterial CT-angiography is useful for detection of the bleeding site

Ion-selective electrodes based on p-tert-butyl-homooxacalixarene di(ethyl)amides

A series of sandwich, monomeric, dimeric and polymeric complexes supported with 1,8-xanthone-18-crown-5 (L) were synthesised. Mass spectrum experiments suggested the existence of sandwich and monomeric complexes in solution. And the structure characterisations of six new complexes by single-crystal X-ray diffraction show the strong coordination of xanthone-18-crown-5 carbonyl oxygen with alkaline earth metal cation, which results high fluorescent increase in alkaline earth metal complexes.. - Polish Ministry of Higher Education and Science [N N204 274235]. - Financial support from the Polish Ministry of Higher Education and Science, Grant No. N N204 274235, is gratefully acknowledged. We also thank Dr J. Chojnacki from Gdansk University of Technology for X-ray crystal structure determination