Pulsed hydraulic-pressure-responsive self-cleaning membrane.

Pressure-driven membranes is a widely used separation technology in a range of industries, such as water purification, bioprocessing, food processing and chemical production1,2. Despite their numerous advantages, such as modular design and minimal footprint, inevitable membrane fouling is the key challenge in most practical applications3. Fouling limits membrane performance by reducing permeate flux or increasing pressure requirements, which results in higher energetic operation and maintenance costs4-7. Here we report a hydraulic-pressure-responsive membrane (PiezoMem) to transform pressure pulses into electroactive responses for in situ self-cleaning. A transient hydraulic pressure fluctuation across the membrane results in generation of current pulses and rapid voltage oscillations (peak, +5.0/-3.2 V) capable of foulant degradation and repulsion without the need for supplementary chemical cleaning agents, secondary waste disposal or further external stimuli3,8-13. PiezoMem showed broad-spectrum antifouling action towards a range of membrane foulants, including organic molecules, oil droplets, proteins, bacteria and inorganic colloids, through reactive oxygen species (ROS) production and dielectrophoretic repulsion.

Electric Demulsification Membrane Technology for Confined Separation of Oil-Water Emulsions.

Demulsification technology for separation of oil-water (O/W) emulsions, especially those stabilized by surfactants, is urgently needed yet remains highly challenging due to their inherent stability characteristics. Electrocoalescence has emerged as a promising solution owing to its simplicity, efficacy, and versatility, yet hindered by substantial energy consumption (e.g., >50 kWh/m3) along with undesirable Faradic reactions. Herein, we propose an innovative electric demulsification technology that leverages conductive membrane microchannels to confine oil droplets from the oil-water emulsion for achieving high energy-efficient coalescence of oil droplets. The proposed system reduces the required voltage down to 12 V, 2 orders of magnitude lower than that of conventional electrocoalescence systems, while achieving a similar separation efficacy of 91.4 ± 3.0% at a low energy consumption (3 kWh/m3) and an ultrahigh permeability >3000 L/(m2·h·bar). In situ fluorescence microscopy combined with COMSOL simulations provided insight into the fundamental mechanistic steps of an electric demulsification process confined to membrane microchannels: (1) rapid electric-field redistribution of oil droplet surfactant molecules, (2) enhanced collision probability due to confined oil droplet concentration under dielectrophoretic forces, and (3) increased collision efficacy facilitated by the membrane pore structure. This strategy may revolutionize the next generation of demulsification and oil-water separation innovations.

Ethnic differences in the prevalence of amyloid positivity and cognitive trajectories.

INTRODUCTION: We investigated the prevalence of amyloid beta (Aß) positivity (+) and cognitive trajectories in Koreans and non-Hispanic Whites (NHWs). METHODS: We included 5121 Koreans from multiple centers across South Korea and 929 NHWs from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Participants underwent Aß positron emission tomography and were categorized into cognitively unimpaired (CU), mild cognitive impairment (MCI), and dementia stages. Age, sex, education, and apolipoprotein E. genotype were adjusted using multivariable logistic regression and stabilized inverse probability of treatment weights based on the propensity scores to mitigate imbalances in these variables. RESULTS: The prevalence of Aß+ was lower in CU Koreans than in CU NHWs (adjusted odds ratio 0.60). Aß+ Koreans showed a faster cognitive decline than Aß+ NHWs in the CU (B = -0.314, p = .004) and MCI stages (B = -0.385, p < .001). DISCUSSION: Ethnic characteristics of Aß biomarkers should be considered in research and clinical application of Aß-targeted therapies in diverse populations. HIGHLIGHTS: Koreans have a lower prevalence of Aß positivity compared to NHWs in the CU stage. The effects of Alzheimer's risk factors on Aß positivity differ between Koreans and NHWs. Aß-positive (Aß+) Koreans show faster cognitive decline than Aß+ NHWs in the CU and MCI stages.

Distinct effects of blood pressure parameters on Alzheimer's and vascular markers in 1,952 Asian individuals without dementia.

BACKGROUND: Risk factors for cardiovascular disease, including elevated blood pressure, are known to increase risk of Alzheimer's disease. There has been increasing awareness of the relationship between long-term blood pressure (BP) patterns and their effects on the brain. We aimed to investigate the association of repeated BP measurements with Alzheimer's and vascular disease markers. METHODS: We recruited 1,952 participants without dementia between August 2015 and February 2022. During serial clinic visits, we assessed both systolic BP (SBP) and diastolic BP (DBP), and visit-to-visit BP variability (BPV) was quantified from repeated measurements. In order to investigate the relationship of mean SBP (or DBP) with Alzheimer's and vascular markers and cognition, we performed multiple linear and logistic regression analyses after controlling for potential confounders (Model 1). Next, we investigated the relationship of with variation of SBP (or DBP) with the aforementioned variables by adding it into Model 1 (Model 2). In addition, mediation analyses were conducted to determine mediation effects of Alzheimer's and vascular makers on the relationship between BP parameters and cognitive impairment. RESULTS: High Aß uptake was associated with greater mean SBP (ß = 1.049, 95% confidence interval 1.016-1.083). High vascular burden was positively associated with mean SBP (odds ratio = 1.293, 95% CI 1.015-1.647) and mean DBP (1.390, 1.098-1.757). High tau uptake was related to greater systolic BPV (0.094, 0.001-0.187) and diastolic BPV (0.096, 0.007-0.184). High Aß uptake partially mediated the relationship between mean SBP and the Mini-Mental State Examination (MMSE) scores. Hippocampal atrophy mediated the relationship between diastolic BPV and MMSE scores. CONCLUSIONS: Each BP parameter affects Alzheimer's and vascular disease markers differently, which in turn leads to cognitive impairment. Therefore, it is necessary to appropriately control specific BP parameters to prevent the development of dementia. Furthermore, a better understanding of pathways from specific BP parameters to cognitive impairments might enable us to select the managements targeting the specific BP parameters to prevent dementia effectively.

Distinct Cognitive Trajectories According to Amyloid Positivity in Non-Alzheimer Disease Dementias.

BACKGROUND: The clinical effects of ß-amyloid positivity (Aß+) on copathologies in various dementias remain relatively underexamined. Thus, the present study was conducted to investigate the prevalence and clinical effects of Aß+ in subcortical vascular cognitive impairment (SVCI) and frontotemporal dementia (FTD). PATIENTS AND METHODS: We enrolled SVCI (n = 583), FTD (n = 152), and cognitively unimpaired (CU) participants (n = 1,249) who underwent Aß PET scans. The odds of having Aß+ were subsequently compared among the diagnostic groups (CU, SVCI, and FTD) according to age and apolipoprotein E genotype. Additionally, a linear mixed-effects model was used to investigate the effects of Aß+ on cognitive trajectories in SVCI and FTD. RESULTS: Compared with CU, the SVCI group had a higher prevalence of Aß+ in the 75 to 90 years age group (adjusted odds ratio, 1.97; 95% confidence interval, 1.36-2.85; P < 0.001), as well as within the apolipoprotein E ε3/ε3 group (adjusted odds ratio, 1.78; 95% confidence interval, 1.20-2.63; P = 0.001), whereas the FTD group showed no difference in Aß+ prevalence. Aß+ was associated with a worse cognitive trajectory in SVCI (adjusted ß-coefficient = -0.6424; P < 0.001), but not in FTD. CONCLUSIONS: These findings contribute to our understanding of Aß biomarker traits in various dementias in Korea.

Piezoelectricity induced by pulsed hydraulic pressure enables in situ membrane demulsification and oil/water separation.

Recovering oil from oily wastewater is not only for economic gains but also for mitigating environmental pollution. However, demulsification of oil droplets stabilized with surfactants is challenging because of their low surface energy. Although the widely used oil/water separation membrane technologies based on size screening have attracted considerable attention in the past few decades, they are incapable of demulsification of stabilized oil emulsions and the membrane concentrates often require post-processing. Herein, the piezoelectric ceramic membrane (PCM), which can respond to the inherent transmembrane pressure in the pressure-driven membrane processes, was employed to transform hydraulic pressure pulses into electroactive responses to in situ demulsification. The pulsed transmembrane pressure on the PCM results in the generation of considerable rapid voltage oscillations over 3.2 V and a locally high electric field intensity of 7.2 × 107 V/m, which is capable of electrocoalescence with no additional stimuli or high voltage devices. Negative dielectrophoresis (DEP) force occurred in this membrane process and repelled the large size of oil after demulsification away from the PCM surface, ensuring continuous membrane demulsification and oil/water separation. Overall, PCM provides a further opportunity to develop an environmentally friendly and energy-saving electroresponsive membrane technology for practical applications in wastewater treatment.