PulseRider is a self-expanding stent implant used to treat wide-necked aneurysms. As this device has a lower metal mass than conventional stents, it is expected to have a lower rate of ischemic complications and a shorter period with antiplatelet drugs. We experienced in-stent stenosis after endovascular treatment with the PulseRider for a middle cerebral artery aneurysm. A 40-year-old woman with an unruptured aneurysm in the middle cerebral artery bifurcation underwent coil embolization using a PulseRider. The periprocedural course was not problematic, and postoperative angiography showed contrast filling in the aneurysm. The patient was discharged from our hospital on postembolization day 3. However, follow-up angiography after 6 months showed in-stent stenosis. Fortunately, no ischemic complications occurred after treatment. Although the PulseRider is characterized by a low metal mass, it should be noted that this device has some metal markers that can induce in-stent stenosis.
A method of extending the dynamic range of a calibration graph by calculating the initial mass of an analyte on a tungsten strip heater using an atom formation model in electrothermal atomic absorption spectrometry is proposed. The model is based on the assumption that the rate of atom formation, given by a simple Arrhenius-type expression, is a function of the number of atoms in a sample on the heater and the heater temperature. The absorbance for the initial mass of iron chosen as a test analyte was obtained by applying the absorbance at the initial stage of the signals to the model equation, and the calculated values of the mass were plotted against the amount of iron in the test solution to give a calibration graph. To extend the dynamic range further, the light beam from a hollow-cathode lamp was adjusted so as to pass through a region of low atom density above the heater.
Highly concentrated solutions composed of lithium bis(fluorosulfonyl)imide (LiFSI) and sulfolane (SL) are promising liquid electrolytes for lithium metal batteries because of their high anodic stability, low flammability, and high compatibility with lithium metal anodes. However, it is still challenging to obtain the stable lithium metal anodes in the concentrated electrolytes due to their poor wettability to the conventional polyolefin separators. Here, we report that the highly concentrated 1:2.5 LiFSI/SL electrolyte coupled with a three-dimensionally ordered macroporous polyimide (3DOM PI) separator enables the stable lithium plating/stripping cycling with an average Coulombic efficiency of ca. 98% for over 400 cycles at 1.0 mA cm-2. The 3DOM PI separator shows good electrolyte wettability and large electrolyte uptake due to its high porosity and polar constituent of the imide structure, allowing superior cycling performance in the highly concentrated solution, compared with the polyolefin separators. Electrochemical and spectroscopic analyses reveal that the superior cycling stability in the concentrated electrolyte is attributed to the formation of highly stable and Li+ ion conductive solid electrolyte interphase (SEI) layer derived from FSI- anions, which reduces the side reactions of SL with lithium metal, prevents the growth of lithium dendrites, and suppresses the increase in cell impedance over long-term cycling. Our findings demonstrate that polar and porous separators could effectively improve the affinity to the concentrated electrolytes and allow the formation of the anion-derived SEI layer by increasing the salt concentration of the electrolytes, achieving the long-term stable lithium metal anode.
