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Langmuir : the ACS Journal of Surfaces... Sep 2020Using electrical signals to guide materials' deposition has a long-standing history in metal coating, microchip fabrication, and the integration of organics with...
Using electrical signals to guide materials' deposition has a long-standing history in metal coating, microchip fabrication, and the integration of organics with devices. In electrodeposition, however, the conductive materials can be deposited only onto the electrode surfaces. Here, an innovative process is presented to electrofabricate freestanding biopolymer membranes at the interface of electrolytes without any supporting electrodes at the fabrication site. Chitosan, a derivative from the naturally abundant biopolymer chitin, has been broadly explored in electrodeposition for integrating biological entities onto microfabricated devices. It is widely believed that the pH gradients generated at the cathode deprotonate the positively charged chitosan chains into a film on the cathode surface. The interfacial electrofabrication with pH indicators, however, demonstrated that the membrane growth was driven by the instantaneous flow of hydroxyl ions from the ambient alginate solution, rather than the slow propagation of pH gradients from the cathode surface. This interfacial electrofabrication produces freestanding membrane structures and can be expanded to other materials, which presents a new direction in using electrical signals for manufacturing.
Topics: Alginates; Chitosan; Electrodes; Electroplating; Membranes, Artificial
PubMed: 32885979
DOI: 10.1021/acs.langmuir.0c01894 -
Analytical Sciences : the International... Dec 2021We present a resin-packed microchannel that can reduce the radiation exposure risk and secondary radioactive wastes during uranium (U) separation by downscaling the...
We present a resin-packed microchannel that can reduce the radiation exposure risk and secondary radioactive wastes during uranium (U) separation by downscaling the separation using a microchip. Two types of microchips were designed to densely pack the microchannels with resins. The microchannels had almost the same cross-sectional area, but different outer circumferences. A satisfactory separation performance could be obtained by arranging more than ca. 10 resins along the depth and width of the microchannels. A resin-packed microchannel is an effective separation technique for determining the U concentration via inductively coupled plasma mass spectrometry owing to its ability to avoid the contamination of equipment by cesium, and to reduce the matrix effect. The size of the separation site was scaled down to <1/5000 compared to commonly used counterparts. The radiation exposure risk and secondary radioactive wastes can be reduced by 10- and 800-fold, respectively, using a resin-packed microchannel.
Topics: Anion Exchange Resins; Cesium; Seawater; Uranium
PubMed: 34305053
DOI: 10.2116/analsci.21P110 -
Cureus Jan 2024Fistula formation between the urinary tract and the arterial system is very rare, and usually involves the ureter and the adjacent iliac vessels. Communication of the...
Fistula formation between the urinary tract and the arterial system is very rare, and usually involves the ureter and the adjacent iliac vessels. Communication of the ureter with the aorta has been described a few times worldwide, and most of them had a fatal outcome. In our case, a 79-year-old man had a history of total cystectomy for malignancy and diversion of both ureters to a single site in the right hypogastrium with the left one crossing over the aorta. He was admitted elsewhere several times for intermittent hematuria, and four months ago the diagnosis of communication of the left ureter with a mycotic aortic pseudoaneurysm was made. He was then referred to an interventional radiologist who sealed the communication. He was admitted to our hospital four months later in a state of hypovolemic shock and massive hematuria. In lack of information, it seemed to us that he had been treated with endovascular aneurysm repair (EVAR) for uretero-aortic communication, and was experiencing a regression because of endoleak formation. We attempted to treat him as type I endoleak with a proximal extension, and upon failure, with distal extensions, but finally we had to 'build' the entire previous graft from the inside to achieve hemodynamic stability. Our patient remained stable, without endoleak on the post-intervention computed tomography angiography (CTA). Post-operatively, we discovered that the initial operation was the formation of a bifurcated graft with multiple bare stents and coil embolization through them. This was done in an attempt to avoid material infection by the mycotic aneurysm. This is an example of a case where 'things got rough' in a lack of information on patients' medical records. Maybe the time has come to adopt the concept of implanting microchips into humans which would enable doctors to access their medical records. This will only serve as a tool for the benefit of the suffering patients, especially when we are dealing with life-threatening situations with no time to be lost.
PubMed: 38425616
DOI: 10.7759/cureus.53215 -
Scientific Reports May 2023It is estimated that carbon emissions should reach net-zero by 2050 to meet important climate targets. Carbon capture is likely necessary to reach these targets,...
It is estimated that carbon emissions should reach net-zero by 2050 to meet important climate targets. Carbon capture is likely necessary to reach these targets, requiring a long-term storage solution such as geological carbon sequestration. However, as with any subsurface activity, leakage can occur, potentially impacting groundwater quality near the storage site. Rapid detection is essential to mitigate damage to this resource. Since CO will acidify groundwater, the concentrations of acid soluble minerals and associated cations will increase. Thus, an in-situ, real-time element analysis system based on laser-induced breakdown spectroscopy (LIBS) is under development to monitor these elements. The system splits the traditional LIBS system into a miniature, all-optical sensor head built around a passively Q-switch laser fiber coupled to a control unit. Previous work has validated the LIBS technique for use at high pressure as well as the split system design. In this work, a fieldable prototype sensor is developed and tested in an onsite monitoring well where trace elements concentrations (approx. 0-3 ppm) were tracked over 20 days. These concentrations varied in response to local rainfall, diluting with increased rain, demonstrating the ability of a LIBS-based sensor to track trace elements under real-world conditions.
PubMed: 37160918
DOI: 10.1038/s41598-023-32788-x