16 research outputs found
Corona based air-flow using parallel discharge electrodes
A novel air-flow generator based on the effect of ion wind has been developed by the simultaneous generation of both positive and negative ions using two electrodes of opposite polarity placed in parallel. Unlike the conventional unipolar-generators, this bipolar configuration creates an ion wind, which moves away from both electrodes and yields a very low net charge on the device. The electro-hydrodynamic behavior of air-flow has been experimentally and numerically studied. The velocity of ion wind reaches values up to 1.25 m/s using low discharge current 5 mu-A with the kinetic conversion efficiency of 0.65% and the released net charge of ïżœ30 fA, 8 orders of magnitude smaller compared with the discharge current. Due to easy scalability and low net charge, the present configuration is beneficial to applications with space constraints and/or where neutralized discharge process is required, such as inertial fluidic units, circulatory flow heat transfer, electrospun polymer nanofiber to overcome the intrinsically instability of the process, or the formation of low charged aerosol
Dual-pin electrohydrodynamic generator driven by alternating current
We report a unique alternating current (AC) driven corona based air-flow generator using symmetrically arranged
electrodes. Unlike the conventional configuration where one electrode generates charged ions moving
towards the reference electrode, this configuration allows both negative and positive charges to simultaneously
move away from the device and generate ion wind in parallel with the electrodes. In comparison with the direct
current (DC) driven corona generator, the time oscillating AC field allows the device a better stabilization owing
to the independence of ion wind strength from the inter-electrode spacing. Our results by both simulation and
experiment showed that when the AC frequency exceeds a threshold value of 1100 Hz, the electric field at the
electrode tips is determined dominantly by the charge cloud created in the previous half-cycle, resulting in stronger net electric field and thus stronger ion wind. In addition, the electrode separation in the AC driven corona based generator is less critical above the frequency threshold, yielding a more robust design with minimized susceptibility to manufacturing tolerances and impurities on the electrodes. Moreover, lower voltage levels of the AC driven system allow simpler and more economical design in the high voltage circuit of the AC generator
Particle precipitation by bipolar corona discharge ion winds
The paper reports the development of a particle precipitation based aerosol sampler using bipolar
corona discharge ion winds with collected particles of minimized net charge. For the new approach, neutralized particles move towards a sampler under the effect of electric field and dual ion winds. Since there is no electrode or sampling chip installed inside the air-flow channel, impediments to airborne particle flow or ion winds are removed along the flow direction. In addition, the isolation of ion winds, which generate circuit, allows using various materials for the sampling chip including non-conductors and also protecting collected particles from any discharge ignition on the chip. The device mechanism is numerically simulated in OpenFOAM to study the electrofluidodynamic interaction of charged particles and bipolar ion winds. The efficiency of the new approach has been investigated by experiment with a maximum efficiency of 94%. The effects of flow rate, discharge voltage and electrode distances on the method are also evaluated
A hĂșgyhĂłlyag-recidĂva jellemzĆi felsĆ ĂŒregrendszeri daganatos betegekben radikĂĄlis ureteronephrectomia utĂĄn
BevezetĂ©s: Urothelium bĂ©leli a vesemedencĂ©t, a hĂșgyvezetĂ©ket, a hĂșgyhĂłlyagot Ă©s a hĂșgycsĆ proximalis harmadĂĄt, Ăgy ezen terĂŒletek bĂĄrmelyikĂ©n kialakulhat ĂĄtmeneti sejtes carcinoma. A felsĆ ĂŒregrendszeri daganatok ritka elvĂĄltozĂĄsok, jelentĆsĂ©gĂŒket azonban az adja, hogy a hĂșgyhĂłlyagban gyakori a recidĂva, mely kockĂĄzatĂĄnak felmĂ©rĂ©sĂ©re a mai napig nem alakult ki egysĂ©gesen elfogadott rizikĂłbecslĂ©s. CĂ©lkitƱzĂ©s: A felsĆ ĂŒregrendszeri daganatos betegek adatainak ĂĄltalĂĄnos jellemzĂ©se, illetve a hĂșgyhĂłlyag-recidĂvĂĄra vonatkozĂł rizikĂłbecslĂ©s. MĂłdszer: A 2005. januĂĄr 1. Ă©s 2016. december 31. közötti idĆszakban a Semmelweis Egyetem UrolĂłgiai KlinikĂĄjĂĄn radikĂĄlis ureteronephrectomiĂĄval kezelt betegek adatainak tanulmĂĄnyozĂĄsa, statisztikai elemzĂ©se. EredmĂ©nyek: Ătmeneti sejtes felsĆ ĂŒregrendszeri daganat 135 betegnĂ©l igazolĂłdott. A betegeket a mƱtĂ©ttĆl szĂĄmĂtva ĂĄtlagosan 32 hĂłnapig (SD: 30,25) követtĂ©k, ezalatt 31 betegnĂ©l (23%) talĂĄltak hĂșgyhĂłlyag-recidĂvĂĄt, ĂĄtlagosan 19,6 hĂłnap (SD: 29,7) utĂĄn. MinĂ©l idĆsebb korban fedeztĂ©k fel a betegnĂ©l a primer daganatot, annĂĄl hamarabb Ă©szleltek kiĂșjulĂĄst a hĂșgyhĂłlyagban (p = 0,007). A diagnĂłziskor ismert magas vĂ©rnyomĂĄs esetĂ©n is szignifikĂĄnsan korĂĄbban tĂ©rt vissza az elvĂĄltozĂĄs (p = 0,035). KövetkeztetĂ©s: A vizsgĂĄlat eredmĂ©nyei alapjĂĄn az idĆsebb Ă©s multimorbid betegek esetĂ©ben a daganat hamarabb reci- divĂĄlt a hĂșgyhĂłlyagban, ezĂ©rt az Ć figyelmĂŒket kĂŒlönösen Ă©rdemes felhĂvni a rendszeres, cystoscopiĂĄt is magĂĄban foglalĂł ellenĆrzĆ vizsgĂĄlat fontossĂĄgĂĄra mĂĄr a kezelĂ©s megkezdĂ©sekor
A vĂ©rtranszfĂșziĂł gyakorisĂĄga primer csĂpĆprotĂ©zis-beĂŒltetĂ©s utĂĄn
Absztrakt:
BevezetĂ©s: CsĂpĆprotĂ©zis-beĂŒltetĂ©s utĂĄn gyakran van szĂŒksĂ©g
vĂ©rtranszfĂșziĂłra, mely esetenkĂ©nt komoly mellĂ©khatĂĄsokkal jĂĄrhat, nehezen
hozzĂĄfĂ©rhetĆ Ă©s költsĂ©ges. CĂ©lkitƱzĂ©s: MunkĂĄnk cĂ©lja az volt,
hogy megvizsgĂĄljuk, sajĂĄt gyakorlatunkban milyen gyakran van szĂŒksĂ©g primer
csĂpĆprotĂ©zis-beĂŒltetĂ©s sorĂĄn vĂ©rĂĄtömlesztĂ©sre, Ă©s ennek gyakorisĂĄgĂĄt mely
tĂ©nyezĆk befolyĂĄsoljĂĄk. MĂłdszer: VizsgĂĄlatunkban 210,
csĂpĆprotĂ©zis-beĂŒltetĂ©sen ĂĄtesett beteg anyagĂĄt dolgoztuk fel. FeljegyeztĂŒk a
mƱtĂ©t elĆtti hemoglobin- Ă©s hematokritĂ©rtĂ©keket, a betegek Ă©letkorĂĄt, nemĂ©t,
testtömegindexĂ©t, a beĂŒltetett protĂ©zis tĂpusĂĄt, a drĂ©nhasznĂĄlatot, valamint a
perioperatĂv idĆszakban hasznĂĄlt vĂ©ralvadĂĄsgĂĄtlĂł Ă©s a mƱtĂ©t sorĂĄn alkalmazott
vĂ©rzĂ©scsökkentĆ szereket. Az adatokat összevetettĂŒk az alkalmazott transzfĂșziĂł
mennyisĂ©gĂ©vel Ă©s tĂpusĂĄval. EredmĂ©nyek: Ăsszesen a betegek
41%-a kapott vĂ©rkĂ©szĂtmĂ©nyt, az allogĂ©n transzfĂșziĂł arĂĄnya 8,6% volt. Az
autotranszfĂșziĂłs betegek nem igĂ©nyeltek allogĂ©nvĂ©r-ĂĄtömlesztĂ©st. A transzfĂșziĂłs
igĂ©ny fĂŒggött a preoperatĂv hemoglobin- Ă©s hematokritĂ©rtĂ©kektĆl, a protĂ©zis
tĂpusĂĄtĂłl, a drĂ©nhasznĂĄlattĂłl Ă©s a vĂ©rzĂ©scsillapĂtĂł szerek hasznĂĄlatĂĄtĂłl. A
vĂ©rĂĄtömlesztĂ©s mennyisĂ©ge nem mutatott összefĂŒggĂ©st a betegek nemĂ©vel Ă©s
testtömegindexével. Következtetés: Vizsgålatunk alapjån allogén
vĂ©r transzfĂșziĂłjĂĄra az esetek kevesebb mint 10%-ĂĄban van szĂŒksĂ©g primer
csĂpĆprotĂ©zis-beĂŒltetĂ©s sorĂĄn. A vĂ©rĂĄtömlesztĂ©st a leginkĂĄbb a preoperatĂv
hemoglobin- Ă©s hematokritĂ©rtĂ©kek, valamint az alkalmazott, fibrinolĂzist gĂĄtlĂł
szerek befolyĂĄsoljĂĄk. Az autotranszfĂșziĂł alkalmas mĂłdszer az
allogĂ©nvĂ©r-ĂĄtömlesztĂ©s elkerĂŒlĂ©sĂ©re. Orv Hetil. 2020; 161(8): 290â294.
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Abstract:
Introduction: Total hip arthroplasty is one of the most common
surgical procedures that requires blood transfusion, with the possible risk of
significant complications. Aim: A retrospective study was
performed to analyze the predictors of blood transfusion after primary total hip
arthroplasty. Method: We collected the data of 210 consecutive
patients undergoing total hip arthroplasty. Patientâs data, preoperative
hemoglobin and hematocrit level, the type of the prosthesis, the use of a
suction drain, tranexamic acid or anticoagulants and the type and amount of
blood transfusion were recorded. Results: A total of 41% of our
patients required transfusion, 8.6% receiving allogenic blood. Significant
predictors of allogenic blood transfusion were preoperative hemoglobin and
hematocrit levels, the type of prosthesis, the use of suction drainage and the
use of tranexamic acid. Patients with pre-donated autologous blood did not
require allogenic blood transfusion. Conclusion: Based on our
study, total hip arthroplasty necessitates allogenic blood transfusion in 8.6%.
Major predictors associated with the need for transfusion are preoperative
hemoglobin and hematocrit levels, the type of prosthesis, the use of suction
drainage and the use of tranexamic acid. Pre-donated autologous blood helps to
reduce allogenic transfusion rate. Orv Hetil. 2020; 161(8): 290â294
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