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1. Functionalized electrospun polymer nanofibers for treatment of water contaminated with uranium

   https://doi.org/10.1039/C9EW00834A  

   Johns, Adam; Qian, Jiajie; Carolan, Margaret E.; Shaikh, Nabil; Peroutka, Allison; Seeger, Anna; Cerrato, José M.; Forbes, Tori Z.; Cwiertny, David M. (March 2020, Environmental Science: Water Research & Technology)

   Uranium (U) contamination of drinking water often affects communities with limited resources, presenting unique technology challenges for U 6+ treatment. Here, we develop a suite of chemically functionalized polymer (polyacrylonitrile; PAN) nanofibers for low pressure reactive filtration applications for U 6+ removal. Binding agents with either nitrogen-containing or phosphorous-based ( e.g. , phosphonic acid) functionalities were blended (at 1–3 wt%) into PAN sol gels used for electrospinning, yielding functionalized nanofiber mats. For comparison, we also functionalized PAN nanofibers with amidoxime (AO) moieties, a group well-recognized for its specificity in U 6+ uptake. For optimal N-based (Aliquat® 336 or Aq) and P-containing [hexadecylphosphonic acid (HPDA) and bis(2-ethylhexyl)phosphate (HDEHP)] binding agents, we then explored their use for U 6+ removal across a range of pH values (pH 2–7), U 6+ concentrations (up to 10 μM), and in flow through systems simulating point of use (POU) water treatment. As expected from the use of quaternary ammonium groups in ion exchange, Aq-containing materials appear to sequester U 6+ by electrostatic interactions; while uptake by these materials is limited, it is greatest at circumneutral pH where positively charged N groups bind negatively charged U 6+ complexes. In contrast, HDPA and HDEHP perform best at acidic pH representative of mine drainage, where surface complexation of the uranyl cation likely drives uptake. Complexation by AO exhibited the best performance across all pH values, although U 6+ uptake via surface precipitation may also occur near circumneutral pH values and at high (10 μM) dissolved U 6+ concentrations. In simulated POU treatment studies using a dead-end filtration system, we observed U removal in AO-PAN systems that is insensitive to common co-solutes in groundwater ( e.g. , hardness and alkalinity). While more research is needed, our results suggest that only 80 g (about 0.2 lbs.) of AO-PAN filter material would be needed to treat an individual's water supply (contaminated at ten-times the U.S. EPA maximum contaminant level for U) for one year. 

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2. Standing of Electrochemical Sensors on the 250th Anniversary of the USA

   https://doi.org/10.1149/1945-7111/ae67af  

   Kaushik, Ajeet; Soundappan, Thiagarajan; Mujawar, Mubarak A; Bhansali, Shekhar (May 2026, Journal of The Electrochemical Society)

   Since the discovery of oxygen meters by Leland C. Clark (1956), the United States of America (USA) has been continually investigating efficient electrochemical sensors (E-Sens) to measure markers in line with demand and scope. The success of the glucometer (1962) accelerated the focus from developing selective, sensitive, and stable (SSS) sensing prototypes. Over time, in the USA, systematic multidisciplinary research is being conducted to overcome sensing challenges and achieve desired features, such as high sensitivity, high selectivity, longer stability, portability, personalized sensing, and validation to transform sensing prototypes for efficient management of targeted issues. Such sensing technology, supported by 4th (nano-enabled chips and sensing prototypes), 5th [Internet of Things (IoT)-based approaches, i.e., hardware and electronics], and 6th generation [Artificial Intelligence (AI)-based approaches, i.e., software] E-Sens technology, to transform them into acceptable, affordable, and applicable (AAA) commercial products with a market. Such optimized and transformative E-Sens perform testing in point-of-care (PoC) and point-of-use (PoU) settings to track a marker, perform risk assessments, and decision-making, needed to support the quality of life. To highlight these state-of-the-art E-Sens on the 250th independent anniversary of the USA, this comprehensive commentary article discusses the journey and standing of E-Sens, along with trends, challenges, and perspectives on personalized sensing. 

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3. Accumulation on and extraction of lead from point-of-use filters for evaluating lead exposure from drinking water

   https://doi.org/10.1039/d0ew00496k  

   Pan, Weiyi; Johnson, Elizabeth R.; Giammar, Daniel E. (October 2020, Environmental Science: Water Research & Technology)

   null (Ed.)

   The precise quantification of Pb exposure from tap water can help water utilities and public health organizations assess and mitigate elevated Pb concentrations. Several sampling protocols have been developed for this purpose; however, each existing protocol has limitations associated with sampling time, sample sizes, and ease of application. This study confirmed the ability of point-of-use faucet filters to accumulate Pb and then developed an extraction method that can enable quantification of Pb exposure from tap water. Nearly all Pb from both real and synthetic tap water was accumulated on POU filters, and four different methods for extracting the accumulated Pb were evaluated. Approximately 100% Pb recovery was achieved with a single pass flow-through method using a nitric acid solution. This Pb exposure quantification method could potentially be applied to real drinking water systems to provide an effective indication of Pb exposure from tap water. 

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4. Exceptional Point of Degeneracy as a Desirable Point of Operation for Oscillator With Discrete Nonlinear Gain and Radiating Elements

   https://doi.org/10.23919/USNC-URSINRSM57467.2022.9881400  

   Mealy, Tarek; Nikzamir, Alireza; Abdelshafy, Ahmed F.; Capolino, Filippo (January 2022, 2022 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM))

   An oscillator made of a periodic waveguide comprising of uniform lossless segments with discrete nonlinear gain and radiating resistive elements prefers to operate at exceptional point of degeneracy (EPD). The steady-state regime is an EPD with π phase shift between unit cells, for various choices of small signal gain of the nonlinear elements and number of unit cells. We demonstrated this fact by monitoring both current and voltage across each nonlinear gain element and finding its effective admittance at the oscillating frequency and checking the degeneracy of the eigenmodes at such point. The EPD studied here is very promising for many applications that incorporate discrete distributed coherent sources and radiation-loss elements. Operating in the vicinity of such special degeneracy conditions may lead to potential performance enhancement in the various microwave, THz and optical systems with distributed gain and radiation, paving the way for a new class of active integrated antenna arrays and radiating laser arrays. 

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5. Proof-of-Execution: Low-Latency Consensus via Speculative Execution

   https://doi.org/10.1145/3774322  

   Hellings, Jelle; Gupta, Suyash; Rahnama, Sajjad; Chen, Junchao; Sana, Celine; Sadoghi, Mohammad (September 2026, ACM Transactions on Database Systems)

   The introduction ofBitcoinfueled the development of blockchain-based resilient data management systems that are resilient against failures, enable federated data management, and can support data provenance. The key factor determining the performance of such resilient data management systems is the consensus protocol used by the system to replicate client transactions among all participants. Unfortunately, existing high-throughput consensus protocols are costly and impose significant latency on transaction processing, which rules out their usage in responsive high-performance data management systems. In this work, we improve on this situation by introducing theProof-of-Execution consensus protocol(PoE), a consensus protocol designed for high-performance low-latency resilient data management.PoEintroducesspeculative execution, which minimizes latency by starting execution before consensus is reached, andPoEintroducesproof-of-executionsto guarantee successful execution to clients. Furthermore,PoEintroduces a single-round check-commit protocol to reduce the overall communication costs of consensus. Hence, we believe thatPoEis a promising step towards flexible general-purpose low-latency resilient data management systems. 

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