Impact of magnetic and electric fields on the free energy to form a calcium carbonate ion-pair.

Electromagnetic fields are used in water treatment and desalination to regulate scale formation and extend the lifetime of membranes. External electric and magnetic fields can promote or suppress mineral nucleation and growth. However, the molecular-scale mechanisms of such processes remain unknown. Computing the free energies needed to form ion pairs under external fields provides important insights into understanding the elemental steps during the initial formation of mineral scales. In this paper, we used molecular dynamics combined with metadynamics simulations to investigate the free energies of forming the [Ca-CO3]0 ion pair, a fundamental building block of carbonate scales, under a range of magnetic (up to 10 T) and electric (up to 10 V m-1) fields in water. The presence of constant magnetic or electric fields favored the ion pairing reaction and lowered the free energies by up to 3% to 6%. The internal energy and entropic components of the free energy showed significant changes and exhibited non-linear behavior with increasing field strength. The [Ca-CO3]0 ion pairing is an entropy-driven process in the absence of an external field, but the mechanism shifts to an internal energy-driven process under selected external fields, suggesting possible changes in the nucleation pathways.

Thermal optimization of a high heat load liquid-metal-bath cooled mirror at the Hefei Advanced Light Facility.

Within the beamlines of diffraction-limited storage rings, the liquid-metal-bath cooling scheme is a prevalent choice for the cooling of high-heat load mirrors. This study employs the finite element analysis method to evaluate the thermal deformations of liquid-metal-bath horizontally deflecting mirrors in the Hefei Advanced Light Facility. In particular, we introduce a novel optimization strategy to obtain the optimal thermal deformation scenario, which also satisfies mechanical design requirements. Moreover, a concurrent optimization approach across multiple structural parameters of mirrors is adopted to attain globally optimal thermal deformation. Following the optimization of the mirror's structural parameters, the curvature radius increases to 227 km, while the residual slope error decreases to 36.3 nrad at 6 eV in the meridian direction. The ray tracing analysis of the beam demonstrates a considerable reduction in the influence of thermal deformation on the beam's focal point. This work proposes an optimization method for designing cooling schemes under mechanical constraints.

Ferricyanide-Mediated, Electrocatalytic Mechanism of Electrochemical Aptamer-Based Sensor Supports Ultrasensitive Analysis of Cardiac Troponin I in Clinical Samples.

Rapid, reagent-free, and ultrasensitive analysis of cardiac troponin I (cTnI) is of significance for early diagnosis of acute myocardial infarction (AMI). The electrochemical aptamer-based (EAB) sensors are promising candidates to fill this role as they are reagentless and can be directly interrogated in complex matrices (e.g., blood). To achieve high sensitivity, EAB sensors typically require nanomaterials or other amplification strategies, which often involves a cumbersome fabrication process. To circumvent this, here we develop a simple yet effective electrocatalytic electrochemical aptamer-based (Ec-EAB) sensor that utilizes target-induced regulation of the catalytic mechanism to achieve ultrasensitive measurement of cTnI. In this assay, we employed a probe-attached redox reporter (i.e., methylene blue, MB) and a solution-diffusive redox reporter (i.e., Fe(CN)63-) to generate two signals, of which the latter is used to catalyze MB to amplify aptamer-mediated charge transfer. The recognition of target altered the diffusion of catalysts (2.2 × 10-9 mol/cm2 in the target-free state versus 1.2 × 10-9 mol/cm2 in the target-bound state) and thus electrocatalytical efficiency, enabling ultrasensitive measurement of cTnI with a 1000-fold improvement in their sensitivity (a limit of detection value: 10 pg/mL).

Deciphering molecular heterogeneity and dynamics of human hippocampal neural stem cells at different ages and injury states.

While accumulated publications support the existence of neurogenesis in the adult human hippocampus, the homeostasis and developmental potentials of neural stem cells (NSCs) under different contexts remain unclear. Based on our generated single-nucleus atlas of the human hippocampus across neonatal, adult, aging, and injury, we dissected the molecular heterogeneity and transcriptional dynamics of human hippocampal NSCs under different contexts. We further identified new specific neurogenic lineage markers that overcome the lack of specificity found in some well-known markers. Based on developmental trajectory and molecular signatures, we found that a subset of NSCs exhibit quiescent properties after birth, and most NSCs become deep quiescence during aging. Furthermore, certain deep quiescent NSCs are reactivated following stroke injury. Together, our findings provide valuable insights into the development, aging, and reactivation of the human hippocampal NSCs, and help to explain why adult hippocampal neurogenesis is infrequently observed in humans.

A pH-independent electrochemical aptamer-based biosensor supports quantitative, real-time measurement in vivo.

The development of biosensors capable of achieving accurate and precise molecular measurements in the living body in pH-variable biological environments (e.g. subcellular organelles, biological fluids and organs) plays a significant role in personalized medicine. Because they recapitulate the conformation-linked signaling mechanisms, electrochemical aptamer-based (E-AB) sensors are good candidates to fill this role. However, this class of sensors suffers from a lack of a stable and pH-independent redox reporter to support their utility under pH-variable conditions. Here, in response, we demonstrate the efficiency of an electron donor π-extended tetrathiafulvalene (exTTF) as an excellent candidate (due to its good electrochemical stability and no proton participation in its redox reaction) of pH-independent redox reporters. Its use has allowed improvement of E-AB sensing performance in biological fluids under different pH conditions, achieving high-frequency, real-time molecular measurements in biological samples both in vitro and in the bladders of living rats.

The water footprint of hydraulic fracturing under different hydroclimate conditions in the Central and Western United States.

The oil and gas (O&G) exploitation via hydraulic fracturing (HF) has augmented both energy production and water demand in the United States. Despite the geographical coincidence of U.S. shale plays with water-scarce areas, the water footprint of HF under drought conditions, as well as its impacts on local water allocation, have not been well understood. In this study, we investigated the water consumption by HF activities under different hydroclimate conditions in eleven O&G-producing states in the central and western U.S. from 2011 to 2020. Our results show that the water consumption under abnormally dry or drought climates accounted for 49.7 % (475.3 billion gallons or 1.8 billion m3) of total water usage of HF, with 9 % (86.1 billion gallons or 325.9 million m3) of water usage occurring under extreme or exceptional drought conditions. The water usage of HF under arid conditions can translate to high densities of water footprint at the local scale, equivalent to >10 % and 50 % of the annual water usage by the irrigation and domestic sectors in 6-29 irrigation-active counties and 11-51 counties (depending on the specific year), respectively. Such water stress imposed by O&G production, however, can be effectively mitigated by the reuse of flowback and produced water. Our findings, for the first time, quantify the water footprint of HF as a function of hydroclimate condition, providing evidence that the water consumption by HF intensifies local water competition and alters water supply threatened by climate variability. This renders wastewater reuse necessary to maintain water sustainability of O&G-producing regions in the context of both a rising O&G industry and a changing climate.

Long-Chain PFASs-Free Omniphobic Membranes for Sustained Membrane Distillation.

Omniphobic membranes possessing high wetting resistance have been created for the treatment of challenging hypersaline feedwaters with low surface tension through membrane distillation (MD). However, virtually all such membranes are fabricated with long-chain per- and polyfluoroalkyl substances (PFASs, ≥8 fluorinated carbons). The environmental risks and high bioaccumulation potential of long-chain PFASs have raised increasing concerns. Developing highly wetting-resistant MD membranes while avoiding the use of long-chain PFASs is essential to improve the viability of MD for resilient and sustainable water purification. We demonstrate that MD membranes with exceptional wetting resistance can be designed through the combination of hierarchically structured membranes consisting of re-entrant texture at different length scales and (ultra)short-chain fluorocarbons, which have lower acute toxicity and bioaccumulation potentials than long-chain PFASs. Our hierarchically structured membrane with three-tier micro/nanostructure fabricated with short-chain fluorocarbon possesses superior wetting resistance, which is comparable to or higher than the long-chain PFASs-based omniphobic membranes reported in the literature. Furthermore, the hierarchically structured membranes fabricated with ultrashort-chain fluorocarbons display improved wetting resistance against feedwaters with low surface tension. Our findings indicate that long-chain PFASs are not required when designing wetting-resistant membranes and that the balance between sustainability and wetting resistance should be tailored to the wetting potential of the feedwater.

BRN2 as a key gene drives the early primate telencephalon development.

Evolutionary mutations in primate-specific genes drove primate cortex expansion. However, whether conserved genes with previously unidentified functions also play a key role in primate brain expansion remains unknown. Here, we focus on BRN2 (POU3F2), a gene encoding a neural transcription factor commonly expressed in both primates and mice. Compared to the limited effects on mouse brain development, BRN2 biallelic knockout in cynomolgus monkeys (Macaca fascicularis) is lethal before midgestation. Histology analysis and single-cell transcriptome show that BRN2 deficiency decreases RGC expansion, induces precocious differentiation, and alters the trajectory of neurogenesis in the telencephalon. BRN2, serving as an upstream factor, controls specification and differentiation of ganglionic eminences. In addition, we identified the conserved function of BRN2 in cynomolgus monkeys to human RGCs. BRN2 may function by directly regulating SOX2 and STAT3 and maintaining HOPX. Our findings reveal a previously unknown mechanism that BRN2, a conserved gene, drives early primate telencephalon development by gaining novel mechanistic functions.

Assessment of the invisible blood contamination on nurses' gloved hands during vascular access procedures in a hemodialysis unit.

A prospective study was conducted to assess potential invisible blood contamination on nurses' gloved hands during vascular access procedures using the occult blood detection method in a hemodialysis unit. 60.13% (273/454) of samples tested positive for hemoglobin. These results highlighted the importance of hand hygiene and glove change during hemodialysis access care.

Quantitative assessment of AD markers using naked eyes: point-of-care testing with paper-based lateral flow immunoassay.

Aß42 is one of the most extensively studied blood and Cerebrospinal fluid (CSF) biomarkers for the diagnosis of symptomatic and prodromal Alzheimer's disease (AD). Because of the heterogeneity and transient nature of Aß42 oligomers (Aß42Os), the development of technologies for dynamically detecting changes in the blood or CSF levels of Aß42 monomers (Aß42Ms) and Aß42Os is essential for the accurate diagnosis of AD. The currently commonly used Aß42 ELISA test kits usually mis-detected the elevated Aß42Os, leading to incomplete analysis and underestimation of soluble Aß42, resulting in a comprised performance in AD diagnosis. Herein, we developed a dual-target lateral flow immunoassay (dLFI) using anti-Aß42 monoclonal antibodies 1F12 and 2C6 for the rapid and point-of-care detection of Aß42Ms and Aß42Os in blood samples within 30 min for AD diagnosis. By naked eye observation, the visual detection limit of Aß42Ms or/and Aß42Os in dLFI was 154 pg/mL. The test results for dLFI were similar to those observed in the enzyme-linked immunosorbent assay (ELISA). Therefore, this paper-based dLFI provides a practical and rapid method for the on-site detection of two biomarkers in blood or CSF samples without the need for additional expertise or equipment.

Development and Application of an Immunocapture PCR Diagnostic Assay Based on the Monoclonal Antibody for the Detection of Shigella.

BACKGROUND: Shigella is among the most important human pathogenic microorganisms, infecting both humans and nonhuman and causing clinically severe diarrhea. Shigella must be enriched before detection, which is time-consuming. OBJECTIVES: To develop a sensitive, rapid, and specific method for Shigella detection. MATERIALS AND METHODS: Shigella was used as an antigen to generate monoclonal antibodies (mAbs). mAbs were screened via indirect enzyme-linked immunosorbent assay (ELISA) and western blot, and two mAbs were selected. The mAb A3 showed high affinity and specificity and was used to develop immune magnetic beads (IMBs) for Shigella enrichment. An immunocapture (IC)-PCR primer was designed from the ipaH gene, and IC-PCR was developed based on the IMBs and PCR. RESULTS: This system shortened the Shigella detection time to 70 min. The sensitivity of the IC-PCR was 9 colony-forming units.mL-1 in artificial milk. The accuracy of the IC-PCR was confirmed using 46 clinical samples collected from monkeys. The IC-PCR results were consistent with the serological and biochemical assays. CONCLUSION: The IC-PCR described herein accurately detected Shigella from milk samples, monkeys and can thus be used to complement classical detection methods.

Elucidating the Trade-off between Membrane Wetting Resistance and Water Vapor Flux in Membrane Distillation.

Membrane distillation (MD) has been receiving considerable attention as a promising technology for desalinating industrial wastewaters. While hydrophobic membranes are essential for the process, increasing membrane surface hydrophobicity generally leads to the reduction of water vapor flux. In this study, we investigate the mechanisms responsible for this trade-off relation in MD. We prepared hydrophobic membranes with different degrees of wetting resistance through coating quartz fiber membranes with a series of alkylsilane molecules while preserving the fiber structures. A trade-off between wetting resistance and water vapor flux was observed in direct-contact MD experiments, with the least-wetting-resistant membrane exhibiting twice as high vapor flux as the most wetting-resistant membrane. Electrochemical impedance analysis, combined with fluorescence microscopy, elucidated that a lower wetting resistance (still water-repelling) allows deeper penetration of the liquid-air interfaces into the membrane, resulting in an increased interfacial area and therefore a larger evaporative vapor flux. Finally, we performed osmotic distillation experiments employing anodized alumina membranes that possess straight nanopores with different degrees of wetting resistance, observed no trade-off, and substantiated this proposed mechanism. Our study provides a guideline to tailor the membrane surface wettability to ensure stable MD operations while maximizing the water recovery rate.

Factors associated with post-traumatic stress disorder of nurses exposed to corona virus disease 2019 in China.

Quantitative studies using validated questionnaires on post-traumatic stress disorder (PTSD) of Nurses exposed to corona virus disease 2019 (COVID-19) in China are rare and the baseline PTSD must first be evaluated before prevention. This study aimed to investigate the factors potentially involved in the level of PTSD of Nurses exposed to COVID-19 in China.In this cross-sectional study, male and female Nurses (n = 202) exposed to COVID-19 from HuBei China were included in the final sample. The PTSD Checklist-Civilian (PCL-C) questionnaire and Simplified Coping Style Questionnaire (SCSQ) were used for evaluation. Multivariate stepwise linear regression analysis and spearman correlation test were performed to assess the association between various factors associated with PTSD.The incidence of PTSD in Nurses exposed to COVID-19 was 16.83%, the PCL-C score was 27.00 (21.00-34.00), and the highest score in the three dimensions was avoidance dimension 9.50 (7.00-13.25); multivariable stepwise linear regression analysis showed that job satisfaction and gender were independently associated with lower PCL-C scores (both P < .001); PCL-C scores were correlated with positive coping (r = -0.151, P = .032), negative coping (r = 0.154, P = .029).Nurses exposed to COVID-19 from HuBei China with job satisfaction, male and positive coping had low PCL-C scores which necessitate reducing the PTSD level by ways of improving job satisfaction, positive response, and strengthening the psychological counseling of female nurses in order to reduce the risk of psychological impairment.

Effect of continuous nursing care based on the IKAP theory on the quality of life of patients with chronic obstructive pulmonary disease: A randomized controlled study.

OBJECTIVE: To explore the effect of continuous nursing care based on the Information, Knowledge, Attitude, and Practice (IKAP) theory on the quality of life of patients with chronic obstructive pulmonary disease (COPD). METHODS: This study is a randomized control trial. COPD patients attending the Affiliated Hospital of Inner Mongolia Medical University, China between July 1 and October 31, 2017 were eligible. Following random assignment of participants to either the intervention group or control group, 70 patients (35 in each group) were included in the final sample. The intervention group received nursing care based on the Information, Knowledge, Attitude, and Practice theory, while the control group received standard nursing care. Data were collected before the intervention, 1 month after the intervention, and three months after the intervention. The St. George's Respiratory Questionnaire (SGRQ) was used to measure quality of life. RESULTS: Three months after the intervention, there were significant differences in the total SGRQ score (20.29 ±â€Š10.03 vs 30.14 ±â€Š12.52) and in the three SGRQ dimensions between the intervention group and the control group (P < .05). A repeated-measures analysis of variance showed that the total SGRQ score and the scores for impact and symptoms had a significant time effect (P < .001), that the total SGRQ score and the score for symptoms had a significant interaction effect (P < .05), and that the impact dimension had a significant group effect (P = .042). Pairwise comparisons of the data for the intervention group showed that there were significant differences between the pre-intervention and 1 month after intervention scores as well as between pre-intervention and three months after intervention, for the total SGRQ scores and the scores for impact and symptoms(P < .001). In terms of the impact dimension, there was a significant difference in the intervention group between 1 month after intervention and 3 months after intervention (P = .016). CONCLUSION: Continuous nursing care based on Information, Knowledge, Attitude, and Practice theory improved quality of scores at 3 months after intervention among COPD patients. Given limitations of the study, future large-scale studies are needed to validate our results.

Instrument-Free and Visual Detection of Salmonella Based on Magnetic Nanoparticles and an Antibody Probe Immunosensor.

Salmonella, a common foodborne pathogen, causes many cases of foodborne illness and poses a threat to public health worldwide. Immunological detection systems can be combined with nanoparticles to develop sensitive and portable detection technologies for timely screening of Salmonella infections. Here, we developed an antibody-probe-based immuno-N-hydroxysuccinimide (NHS) bead (AIB) system to detect Salmonella. After adding the antibody probe, Salmonella accumulated in the samples on the surfaces of the immuno-NHS beads (INBs), forming a sandwich structure (INB-Salmonella-probes). We demonstrated the utility of our AIB diagnostic system for detecting Salmonella in water, milk, and eggs, with a sensitivity of 9 CFU mL-1 in less than 50 min. The AIB diagnostic system exhibits highly specific detection and no cross-reaction with other similar microbial strains. With no specialized equipment or technical requirements, the AIB diagnostic method can be used for visual, rapid, and point-of-care detection of Salmonella.

Effect of Excitation Wavelength on Optical Performances of Quantum-Dot-Converted Light-Emitting Diode.

Light-emitting diode (LED) combined with quantum dots (QDs) is an important candidate for next-generation high-quality semiconductor devices. However, the effect of the excitation wavelength on their optical performance has not been fully explored. In this study, green and red QDs are applied to LEDs of different excitation wavelengths from 365 to 455 nm. The blue light is recommended for exciting QDs from the perspective of energy utilization. However, QD LEDs excited at 365 nm have unique advantages in eliminating the original peaks from the LED chip. Moreover, the green or red light excited by ultraviolet light has an advantage in colorimetry. Even for the 455 nm LED with the highest QD concentration at 7.0 wt%, the color quality could not compete with the 365 nm LED with the lowest QD concentration at 0.2 wt%. A 117.5% (NTSC1953) color gamut could be obtained by the 365 nm-excited RGB system, which is 32.6% higher than by the 455 nm-excited solution, and this can help expand the color gamut of LED devices. Consequently, this study provides an understanding of the properties of QD-converted LEDs under different wavelength excitations, and offers a general guide to selecting a pumping source for QDs.

Trade-off in membrane distillation with monolithic omniphobic membranes.

Omniphobic membranes are attractive for membrane distillation (MD) because of their superior wetting resistance. However, a design framework for MD membrane remains incomplete, due to the complexity of omniphobic membrane fabrication and the lack of fundamental relationship between wetting resistance and water vapor permeability. Here we present a particle-free approach that enables rapid fabrication of monolithic omniphobic membranes for MD desalination. Our monolithic omniphobic membranes display excellent wetting resistance and water purification performance in MD desalination of hypersaline feedwater containing surfactants. We identify that a trade-off exists between wetting resistance and water vapor permeability of our monolithic MD membranes. Utilizing membranes with tunable wetting resistance and permeability, we elucidate the underlying mechanism of such trade-off. We envision that our fabrication method as well as the mechanistic insight into the wetting resistance-vapor permeability trade-off will pave the way for smart design of MD membranes in diverse water purification applications.

Identifying Ancient Ceramics Using Laser-Induced Breakdown Spectroscopy Combined with a Back Propagation Neural Network.

This study investigated the rapid identification of ceramics via laser-induced breakdown spectroscopy (LIBS) to realize the identification of ancient ceramics from different regions. Ceramics from different regions may have large differences in their elemental composition. Thus, using LIBS technology for ceramic identification is feasible. The spectral intensities of 11 common elements, namely, Si, Al, Fe, Ca, Mg, Ti, Mn, Na, K, Sr, and Ba, in ceramics were selected as classification indices. Principal component analysis (PCA) and kernel principal component analysis (KPCA) combined with the back propagation (BP) neural network were used to identify ceramics. Furthermore, the effects of the PCA and KPCA data processing methods were compared. Finally, this work aimed to select a suitable method for obtaining spectral data on ceramics identified by LIBS through experiments. Results revealed that LIBS technology could aid the routine, rapid, and on-site analysis of archeological objects to rapidly identify or screen various types of objects.

Antiwetting and Antifouling Janus Membrane for Desalination of Saline Oily Wastewater by Membrane Distillation.

In this study, we develop Janus membranes comprising a hydrophilic zwitterionic polymer layer and an omniphobic (all-liquid-repelling) porous substrate that simultaneously possess fouling and wetting resistances. An omniphobic membrane was first fabricated by attaching silica nanoparticles (SiNPs) to the fibers of a quartz fiber mat, creating multilevel re-entrant structures, followed by surface fluorination to reduce the surface energy. The Janus membrane was then fabricated by grafting a zwitterionic polymer brush layer via surface-initiated atom-transfer radical-polymerization (ATRP) on the omniphobic substrate. Membrane characterizations, including Fourier-transform infrared spectroscopy, fluorescence microscopy, and contact angle measurements, confirm that the surface hydrophilicity can be finely tuned by adjusting the duration of the ATRP reaction. Also, the zwitterionic polymer brush layer was confined on the top surface of the Janus membrane, rendering the surface hydrophilic, while the remaining part of the Janus membrane remained omniphobic, resisting the wicking of low-surface-tension liquids including ethanol and hexane. A static oil-fouling test showed that crude oil droplets irreversibly fouled an omniphobic membrane (without a hydrophilic top layer) in water. In contrast, oil droplets placed on the Janus membrane in air were immediately desorbed upon its immersion in water. Finally, we performed direct-contact membrane distillation (MD) experiments using a crude-oil-in-saline (NaCl) water emulsion as a feed solution, simulating highly saline oily wastewater. The Janus membrane exhibited superior wetting and fouling resistances, with a stable water flux and nearly perfect salt rejection, while an omniphobic membrane failed in the desalination process. Our work highlights the great potential of antiwetting and antifouling Janus membranes for water reclamation from challenging industrial wastewaters through MD.