Molecular mechanism and therapeutic strategy of bile acids in Alzheimer's disease from the emerging perspective of the microbiota-gut-brain axis.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid-ß outside neurons and Tau protein inside neurons. Various pathological mechanisms are implicated in AD, including brain insulin resistance, neuroinflammation, and endocrinal dysregulation of adrenal corticosteroids. These factors collectively contribute to neuronal damage and destruction. Recently, bile acids (BAs), which are metabolites of cholesterol, have shown neuroprotective potential against AD by targeting the above pathological changes. BAs can enter the systematic circulation and cross the blood-brain barrier, subsequently exerting neuroprotective effects by targeting several endogenous receptors. Additionally, BAs interact with the microbiota-gut-brain (MGB) axis to improve immune and neuroendocrine function during AD episodes. Gut microbes impact BA signaling in the brain through their involvement in BA biotransformation. In this review, we summarize the role and molecular mechanisms of BAs in AD while considering the MGB axis and propose novel strategies for preventing the onset and progression of AD.

Synthesis, Optimization and Molecular Self-Assembly Behavior of Alginate-g-Oleylamine Derivatives Based on Ugi Reaction for Hydrophobic Drug Delivery.

To achieve the optimal alginate-based oral formulation for delivery of hydrophobic drugs, on the basis of previous research, we further optimized the synthesis process parameters of alginate-g-oleylamine derivatives (Ugi-FOlT) and explored the effects of different degrees of substitution (DSs) on the molecular self-assembly properties of Ugi-FOlT, as well as the in vitro cytotoxicity and drug release behavior of Ugi-FOlT. The resultant Ugi-FOlT exhibited good amphiphilic properties with the critical micelle concentration (CMC) ranging from 0.043 mg/mL to 0.091 mg/mL, which decreased with the increase in the DS of Ugi-FOlT. Furthermore, Ugi-FOlT was able to self-assemble into spherical micellar aggregates in aqueous solution, whose sizes and zeta potentials with various DSs measured by dynamic light scattering (DLS) were in the range of 653 ± 25~710 ± 40 nm and -58.2 ± 1.92~-48.9 ± 2.86 mV, respectively. In addition, RAW 264.7 macrophages were used for MTT assay to evaluate the in vitro cytotoxicity of Ugi-FOlT in the range of 100~500 µg/mL, and the results indicated good cytocompatibility for Ugi-FOlT. Ugi-FOlT micellar aggregates with favorable stability also showed a certain sustained and pH-responsive release behavior for the hydrophobic drug ibuprofen (IBU). Meanwhile, it is feasible to control the drug release rate by regulating the DS of Ugi-FOlT. The influence of different DSs on the properties of Ugi-FOlT is helpful to fully understand the relationship between the micromolecular structure of Ugi-FOlT and its macroscopic properties.

An Aggregation-Induced Emission-Based Dual Emitting Nanoprobe for Detecting Intracellular pH and Unravelling Metabolic Variations in Differentiating Lymphocytes.

Monitoring T lymphocyte differentiation is essential for understanding T cell fate regulation and advancing adoptive T cell immunotherapy. However, current biomarker analysis methods necessitate cell lysis, leading to source depletion. Intracellular pH (pHi) can be affected by the presence of lactic acid (LA), a metabolic mediator of T cell activity such as glycolysis during T cell activation; therefore, it is a potentially a good biomarker of T cell state. In this work, a dual emitting enhancement-based nanoprobe, namely, AIEgen@F127-AptCD8, was developed to accurately detect the pHi of T cells to "read" the T cell differentiation process. The nanocore of this probe comprises a pair of AIE dyes, TPE-AMC (pH-sensitive moiety) and TPE-TCF, that form a donor-acceptor pair for sensitive detection of pHi by dual emitting enhancement analysis. The nanoprobe exhibits a distinctly sensitive narrow range of pHi values (from 6.0 to 7.4) that can precisely distinguish the differentiated lymphocytes from naïve ones based on their distinct pHi profiles. Activated CD8+ T cells demonstrate lower pHi (6.49 ± 0.09) than the naïve cells (7.26 ± 0.11); Jurkat cells exhibit lower pHi (6.43 ± 0.06) compared to that of nonactivated ones (7.29 ± 0.09) on 7 days post-activation. The glycolytic product profiles in T cells strongly correlate with their pHi profiles, ascertaining the reliability of probing pHi for predicting T cell states. The specificity and dynamic detection capabilities of this nanoprobe make it a promising tool for indirectly and noninvasively monitoring T cell activation and differentiation states.

Role of the microbiota-gut-heart axis between bile acids and cardiovascular disease.

Bile acid (BA) receptors (e.g., farnesoid X-activated receptor, muscarinic receptor) are expressed in cardiomyocytes, endothelial cells, and vascular smooth muscle cells, indicating the relevance of BAs to cardiovascular disease (CVD). Hydrophobic BAs are cardiotoxic, while hydrophilic BAs are cardioprotective. For example, fetal cardiac insufficiency in maternal intrahepatic cholestasis during pregnancy, and the degree of fetal cardiac abnormality, is closely related to the level of hydrophobic BAs in maternal blood and infant blood. However, ursodeoxycholic acid (the most hydrophilic BA) can reverse/prevent these detrimental effects of increased levels of hydrophobic BAs on the heart. The gut microbiota (GM) and GM metabolites (especially secondary BAs) have crucial roles in hypertension, atherosclerosis, unstable angina, and heart failure. Herein, we describe the relationship between CVD and the GM at the BA level. We combine the concept of the "microbiota-gut-heart axis" (MGHA) and postulate the role and mechanism of BAs in CVD development. In addition, the strategies for treating CVD with BAs under the MGHA are proposed.

Association between viral infection and bronchopulmonary dysplasia in preterm infants: a systematic review and meta-analysis.

Bronchopulmonary dysplasia (BPD) is the most common serious complication of very preterm infants (VPI) or very low birth weight (VLBW) infants. Studies implicate viral infections in etiopathogenesis. The aim of this study was to summarize the relationship between viral infections and BPD through a systematic review and meta-analysis. We searched PubMed, Embase, the Web of Science Core Collection, and the Cochrane Database on December 19, 2023. We included observational studies that examined the association between viral infections and BPD in preterm infants. We extracted data on study methods, participant characteristics, exposure assessment, and outcome measures. We assessed study risk of bias using the Newcastle-Ottawa Scale (NOS). We included 17 and 15 studies in the qualitative review and meta-analysis, respectively. The meta-analysis showed a significant association between viral infection and BPD diagnosed at 36 weeks postmenstrual age (odds ratio (OR): 2.42, 95% confidence interval: 1.89-3.09, 13 studies, very low certainty of evidence). In a subgroup analysis of specific viruses, cytomegalovirus (CMV) proved to be significantly associated with BPD diagnosed at 36 weeks postmenstrual age (OR: 2.34, 95% confidence interval: 1.80-3.05, 11 studies). We did not find an association between viral infection and BPD diagnosed on the 28th day of life, probably due to the small sample size of the included prospective studies.  Conclusion: Viral infections, especially CMV, are associated with an increased risk of BPD in preterm infants. Methodologically reliable prospective studies with large samples are needed to validate our conclusions, and high-quality randomized controlled studies are needed to explore the effect of prevention or treatment of viral infections on the incidence of BPD. What is Known: • Studies have attempted to identify viral infections and bronchopulmonary dysplasia in preterm infants; however, results have been inconsistent. What is New: • Systematic demonstration that viral infections, particularly cytomegalovirus, are positively associated with bronchopulmonary dysplasia diagnosed in preterm infants at the 36th week of postmenstrual age. • The importance of screening for viral infections in preterm infants, especially cytomegalovirus. More high-quality studies should be produced in the future to investigate the causal relationship between viral infections and bronchopulmonary dysplasia.

Association of chronic conditions and physical multimorbidity with new-onset incontinence in a nationwide prospective cohort study of older adults ≥ 50 years in China.

BACKGROUND: The relationship between multimorbidity (i.e. ≥ 2 chronic conditions) and incontinence (i.e. urinary and/or faecal incontinence) is underexplored. This study investigated the association between multimorbidity and incident incontinence in Chinese adults aged ≥50 years. METHODS: Data from the 2011 and 2015 waves of the China Health and Retirement Longitudinal Study were used. The association between 12 chronic conditions, multimorbidity and new-onset incontinence was analysed using weighted logistic regression models. Mediation analysis was conducted to explore the potential mediators (self-reported health, subjective memory, depressive symptoms, disability, cognitive function, handgrip strength, mobility limitations, medications and frailty status) between multimorbidity and incontinence. FINDINGS: Among 9,986 individuals aged ≥50 years who were continent at baseline, 5.3% (n = 521) were newly incontinent 4 years later (incident cases). The risk of incident incontinence increased with physical multimorbidity (OR 2.04, 95% CI 1.62-2.57). Compared to no chronic condition, having 1, 2, 3 and ≥ 4 chronic conditions were associated with incident incontinence with OR (95% CI): 1.41 (1.01-1.97), 1.74 (1.24-2.44), 2.82 (1.93-4.12) and 3.99 (2.29-6.95), respectively. The association between multimorbidity and incontinence was mediated by self-reported health (41.2%), medications (26.6%), mobility limitations (20.9%), depressive symptoms (12.8%), disability (11.6%), subjective memory (8.7%) and frailty status (8.3%). CONCLUSION: This longitudinal study found that physical multimorbidity and specific chronic conditions may increase the risk of new-onset incontinence among Chinese adults aged ≥50 years. Self-reported health, medications and mobility limitations seemed to be important intermediate conditions between multimorbidity and incident incontinence.

Association of smoking status and nicotine dependence with multi-morbidity in China: A nationally representative crosssectional study.

INTRODUCTION: Multi-morbidity is a public health priority as it is associated with an increased risk of mortality and a substantial healthcare burden. Smoking is considered a predisposing factor for multi-morbidity, but evidence for an association between multi-morbidity and nicotine dependence is insufficient. This study aimed to explore the association between smoking status, nicotine dependence, and multi-morbidity in China. METHODS: We recruited 11031 Chinese citizens from 31 provinces in 2021 using a multistage stratified cluster sampling strategy to ensure the study population represented national population characteristics. The association between smoking status and multi-morbidity was analyzed using binary logistic regression and multinomial logit regression models. We then analyzed the associations between four kinds of smoking status (age at smoking initiation, cigarette consumption per day, smoking when ill in bed, and inability to control smoking in public places), nicotine dependence, and multi-morbidity among participants who were current smokers. RESULTS: Compared with non-smokers, the odds of multi-morbidity were higher among ex-smokers (adjusted odd ratio, AOR=1.40, 95% CI: 1.07-1.85). The risk of multi-morbidity was greater in participants who were underweight/overweight/obese (AOR=1.90; 95% CI: 1.60-2.26) compared with those who were normal weight. and also greater for drinkers (AOR=1.34; 95% CI: 1.09-1.63) than non-drinkers. Compared with children who began smoking at the age of <15 years, participants aged >18 years had a lower likelihood of multi-morbidity (AOR=0.52; 95% CI: 0.32-0.83). People who consumed ≥31 cigarettes per day (AOR=3.77; 95% CI: 1.47-9.68) and those who smoked when ill in bed (AOR=1.70; 95% CI: 1.10-2.64) were more likely to have multi-morbidity. CONCLUSIONS: Our findings show that smoking behavior, including initiation age, frequency of daily smoking, and still smoking during illness or in public, is a critical risk factor for multi-morbidity, especially when combined with alcohol consumption, physical inactivity, and abnormal weight (underweight, overweight, or obese). This highlights the crucial effect of smoking cessation in the prevention and control of multi-morbidity, especially in patients with three or more diseases. Implementing smoking and lifestyle interventions to promote health would both benefit adults and prevent the next generation from initiating habits that increase the risk of multi-morbidity.

Electrowetting-assisted printing of 3D-architectured microelectrodes inside flexible piezoelectric films for sensitive, robust responses to bending deformation.

The voltage outputs of flexible piezoelectric films after bending deformation have always been limited by two factors, including the incompatible polarization direction with bending strain and the interfacial fatigue failure between the piezoelectric films and the electrode layers, largely hindering the applications in wearable electronics. Herein, we demonstrate a new piezoelectric film design, where 3D-architectured microelectrodes are fabricated inside a piezoelectric film by electrowetting-assisted printing of conductive nano-ink into the pre-formed meshed microchannels in the piezoelectric film. The 3D architectures increase the piezoelectric output of a typical P(VDF-TrFE) film by more than 7 fold compared with the conventional planar design at the same bending radius, and, more importantly, decrease the output attenuation down to only 5.3% after 10 000 bending cycles, less than one third of that for the conventional design. The dependence of piezoelectric outputs on feature sizes of 3D microelectrodes was investigated numerically and experimentally, providing a route for optimizing the 3D architecture design. Different composite piezoelectric films with internal 3D-architectured microelectrodes were fabricated, exhibiting improved piezoelectric outputs under bending deformations, demonstrating that our printing methods could have broad applications in various fields. The fabricated piezoelectric films, worn on human fingers, are used for remotely controlling the robot hand gestures by human-machine interaction; furthermore, the fabricated piezoelectric patches are used to successfully sense the pressure distribution by integrating with spacer arrays to convert the pressing movement into bending deformation, demonstrating the enormous potential of our piezoelectric films in practical applications.

Diagnostics Value of Quantitative Magnetic Resonance Imaging (MRI) in Neonatal Acute Bilirubin Encephalopathy.

Background: This study was designed to investigate the diagnostic value of relative signal intensity of globus pallidus on T1-weighted magnetic resonance imaging (MRI) in neonatal acute bilirubin encephalopathy (ABE). Methods: Participants who were recruited in hospital from April 2019 to May 2020 were grouped into mildly increased total serum bilirubin (TSB) group (n = 30), severely increased TSB group (n = 25), or extremely increased TSB group (n = 10) based on the total serum bilirubin level. Bilirubin-induced neurologic dysfunction scale score was used to determine if participants had acute bilirubin encephalopathy. All neonates underwent conventional brain MRI and the relative signal intensity of globus pallidus was measured on T1-weighted images. The diagnostic value of these 3 indices was assessed by receiver operating characteristic curve analysis. Results: There was a significant correlation between relative signal intensity of globus pallidus and total serum bilirubin level in neonates with hyperbilirubinemia (r = 0.551, P < .001). Relative signal intensity of globus pallidus in the extremely increased TSB group was significantly higher than that in severely increased TSB, mildly increased TSB, and healthy control groups. Relative signal intensity of globus pallidus in the acute bilirubin encephalopathy group was significantly higher than that in the non-acute bilirubin encephalopathy group (P < .01). The area under the receiver operating characteristic curve of the relative signal intensity of globus pallidus was 0.765 (P < .01), with sensitivity of 0.655 and specificity of 0.861. The area under the curve of the total serum bilirubin and visual inspection of globus pallidus signal was 0.621 and 0.579, respectively. The area under the curve of relative signal intensity was significantly greater than that of total serum bilirubin and visual inspection (P = .04 for both). Conclusion: Relative signal intensity of globus pallidus, which is an objective assessment, has the potential to be used as a diagnostic tool for acute bilirubin encephalopathy.

Tiny Ni3S2 boosting MoS2 hydrogen evolution in alkali by enlarging coupling boundaries and stimulating basal plane.

The relatively slow reaction kinetics of the hydrogen evolution reaction (HER) by water electrolysis in alkali hinder its large-scale industrial production. To improve the HER activity in alkaline media, a novel Ni3S2/MoS2/CC catalytic electrode was synthesized by a simple two-step hydrothermal method in this work. The modification of MoS2 by Ni3S2 could facilitate the adsorption and dissociation of water, thus accelerating the alkaline HER kinetics. Moreover, the unique morphology of small Ni3S2 nanoparticles grown on MoS2 nanosheets not only increased the interface coupling boundaries, which acted as the most efficient active sites for the Volmer step in alkaline medium, but also sufficiently activated the MoS2 basal plane, thus providing more active sites. Consequently, Ni3S2/MoS2/CC only needed overpotentials of 189.4 and 240 mV to drive current densities of 100 and 300 mA·cm-2, respectively. More importantly, its catalytic performance of Ni3S2/MoS2/CC even exceeded that of Pt/C at a high current density after 261.7 mA·cm-2 in 1.0 M KOH.

Development and preliminary testing of a questionnaire to measure mobile health information-seeking behaviour in people with cancer.

AIM: The aim of the study was to develop and psychologically test the mobile health information-seeking behaviour (MHISB) questionnaire in people with cancer. DESIGN: Instrument development. METHODS: The study was conducted in three phases in a southeastern city of China from May 2017 to April 2018. In phase one, an item pool was constructed based on a literature review and semistructured interviews. In phase two, expert evaluation and cognitive interviews were used to evaluate the content validity of the questionnaire. In phase three, a cross-sectional study was conducted with people with cancer. Cronbach's α was calculated for reliability analysis. Validity evaluation included content validity and construct validity. RESULTS: The developed MHISB questionnaire has four dimensions (information-seeking frequency, information-seeking self-efficacy, health information evaluation and information-seeking willingness) and 25 items. Psychometric findings were satisfactory and supported the questionnaire's reliability. CONCLUSIONS: The construction process of the MHISB questionnaire was scientific and feasible. The MHISB questionnaire had acceptable validity and reliability, and it requires further improvement in future studies.

NSC-derived exosomes enhance therapeutic effects of NSC transplantation on cerebral ischemia in mice.

Transplantation of neural stem cells (NSCs) has been proved to promote functional rehabilitation of brain lesions including ischemic stroke. However, the therapeutic effects of NSC transplantation are limited by the low survival and differentiation rates of NSCs due to the harsh environment in the brain after ischemic stroke. Here, we employed NSCs derived from human induced pluripotent stem cells together with exosomes extracted from NSCs to treat cerebral ischemia induced by middle cerebral artery occlusion/reperfusion in mice. The results showed that NSC-derived exosomes significantly reduced the inflammatory response, alleviated oxidative stress after NSC transplantation, and facilitated NSCs differentiation in vivo. The combination of NSCs with exosomes ameliorated the injury of brain tissue including cerebral infarction, neuronal death, and glial scarring, and promoted the recovery of motor function. To explore the underlying mechanisms, we analyzed the miRNA profiles of NSC-derived exosomes and the potential downstream genes. Our study provided the rationale for the clinical application of NSC-derived exosomes as a supportive adjuvant for NSC transplantation after stroke.

[Research Progress on the Application of Intervention Mapping in Tertiary Prevention of Cancer].

Intervention mapping (IM) is a framework for formulating theory-and evidence-based health education projects with participatory approaches from ecological perspectives.The intervention program designed via IM plays a role in reducing the exposure of cancer risk factors,increasing cancer prevention behaviors,and promoting early cancer screening and rehabilitation of cancer patients.This study summarizes the characteristics,implementation steps,and application status of IM in tertiary prevention of cancer,aiming to provide reference for the application of IM in the health education projects for cancer in China.

Electronic nose application for detecting different odorants in source water: Possibility and scenario.

The problem of taste and odor (T&O) in drinking water is a widespread societal concern and highlights substantial challenges related to the detection and evaluation of odor in water. In this study, the portable electronic nose PEN3, which is equipped with ten different heated metal sensors, was applied to analyze its applicability, feasibility and application scenarios for the detection of typical odorants, such as 2-methylisobornel (2-MIB), geosmin (GSM), ß-cyclocitral, ß-ionone, and other T&O compounds in source water, while avoiding uncertainties and instability related to manual inspection. All the T&O compounds could be effectively differentiated by principal component analysis (PCA). Linear discriminant analysis (LDA) showed that the odors varied greatly between different samples and could be effectively distinguished. As the odorant concentration increased, the sensor response intensity of the primary identification sensors R6 and R8 increased with a significant positive correlation. For Microcystis aeruginosa, an algae that produces odorants, PCA could distinguish the odors of algae at a series of densities at different concentrations. The responses of R10 showed a significant increase with increasing algae density, implying the production of more aliphatic hydrocarbons and other odor compounds. The results indicated that the electronic nose could provide a promising alternative to traditional unstable and complex detection methods for the detection of odorous substances in surface water and early warning of odor events. This study aimed to provide technical support for rapid monitoring and early warning of odorants in source water management.

Development and preliminary testing of the cancer-related fatigue comprehensive assessment scale in cancer survivors.

BACKGROUND: Tailored management of cancer-related fatigue (CRF) is important for effective coping; however, it has been hindered by the lack of a comprehensive tool that assesses both symptoms and treatable influencing factors. AIMS AND OBJECTIVES: The aim was to develop a cancer-related fatigue comprehensive assessment scale (CRF-CAS) and assess its psychometric properties. DESIGN: This was a mixed-method study. METHODS: The study included two phases which were conducted in Zhejiang Province, China. In phase one, a literature search, brainstorming sessions, Delphi studies, cognitive interviews and a pilot study were conducted to construct and revise CRF-CAS indicators. In phase two, a questionnaire-based survey was conducted among cancer survivors. Item analysis was used to select and optimize indicators. Cronbach's α was calculated for reliability analysis. Validity analysis included concurrent validity and structural validity. RESULTS: A 93-item tool was initially constructed. Phase one ended with revision and optimization. The preliminary scale included five dimensions (CRF symptoms, physical activity, cognitive-emotional status, sleep status, nutritional status) and 30 items. The mean item-content validity index (I-CVI) and scale-level CVI universal agreement (S-CVI/UA) were .98, and the adjusted mean values of Kappa for indicators ranged from .91-1, as evaluated by the expert group. The Pearson correlation coefficient between the CRF-CAS and criterion scales ranged from .337-.862. Cronbach's α coefficient ranged from .624-.728. Respondents agreed that the scale was acceptable for administration and that it contributed to decision-making in fatigue management. Confirmatory factor analysis (CFA) indicated that the CRF-CAS fit well. CONCLUSIONS: The construction process of the CRF-CAS, involving panel discussion and expert and participant evaluations, was shown to be scientific and feasible. The CRF-CAS had relatively good validity and reliability in version 5 of its preliminary scale, which requires further improvement in future studies.

A Microfluidic Platform Revealing Interactions between Leukocytes and Cancer Cells on Topographic Micropatterns.

Immunoassay for detailed analysis of immune-cancer intercellular interactions can achieve more promising diagnosis and treatment strategies for cancers including nasopharyngeal cancer (NPC). In this study, we report a microfluidic live-cell immunoassay integrated with a microtopographic environment to meet the rising demand for monitoring intercellular interactions in different tumor microenvironments. The developed assay allows: (1) coculture of immune cells and cancer cells on tunable (flat or micrograting) substrates, (2) simultaneous detection of different cytokines in a wide working range of 5-5000 pg/mL, and (3) investigation of migration behaviors of mono- and co-cultured cells on flat/grating platforms for revealing the topography-induced intercellular and cytokine responses. Cytokine monitoring was achieved on-chip by implementing a sensitive and selective microbead-based sandwich assay with an antibody on microbeads, target cytokines, and the matching fluorescent-conjugated detection antibody in an array of active peristaltic mixer-assisted cytokine detection microchambers. Moreover, this immunoassay requires a low sample volume down to 0.5 µL and short assay time (30 min) for on-chip cytokine quantifications. We validated the biocompatibility of the co-culture strategy between immune cells and NPC cells and compared the different immunological states of undifferentiated THP-1 monocytic cells or PMA-differentiated THP-1 macrophages co-culturing with NP460 and NPC43 on topographical and planar substrates, respectively. Hence, the integrated microfluidic platform provides an efficient, broad-range and precise on-chip cytokine detection approach, eliminates the manual sampling procedures and allows on-chip continuous cytokine monitoring without perturbing intercellular microenvironments on different topographical ECM substrates, which has the potential of providing clinical significance in early immune diagnosis, personalized immunotherapy, and precision medicine.

Current research and future prospects of IVOCT imaging-based detection of the vascular lumen and vulnerable plaque.

Intravascular optical coherence tomography (IVOCT) is an imaging method that has developed rapidly in recent years and is useful in coronary atherosclerosis diagnosis. It is widely used in the assessment of vulnerable plaque. This review summarizes the main research methods used in recent years for blood vessel lumen boundary detection and segmentation and vulnerable plaque segmentation and classification. This article aims to comprehensively and systematically introduce the research progress on internal tissues of blood vessels based on IVOCT images. The characteristics and advantages of various methods have been summarized to provide theoretical ideas and methods for the reference of relevant researchers and scholars.

Identify the Activity Origin of Pt Single-Atom Catalyst via Atom-by-Atom Counting.

Atom dispersion in metal supported catalysts is vital as it structurally accounts for their catalytic performances. Since practical catalysts normally present structural diversity, such as the coexistence of single atoms, clusters, and particles, traditional spectroscopy methods including chemisorption, titration, and X-ray absorption, however, provide only an averaged description about the atom dispersion but are not able to distinguish localized structural divergence. In this work, through developing a methodology of electron-microscopy-based atom recognition statistics (EMARS), catalyst dispersion has been redefined at atomic precision in real space via the statistically counting 18 000+ Pt atoms for a Pt/Al2O3 industrial reforming catalyst. The EMARS results combined with in situ microscopy evidence disclose that the activity for aromatics production quantitatively correlates with the density of Pt single-atoms, while Pt clusters contribute no direct activity but could kinetically transform into single-atoms when being heated under an oxidative atmosphere. Compared to EMARS, the traditional hydrogen-oxygen titration method is found to induce serious bias in the Pt dispersion in reference to actual activity. This distinctive capability of EMARS for metal dispersion quantification offers a possibility of directly identifying the catalysis roles of different metal species in a practical catalyst via atom-resolved statistics.

Effects of organic matter, ammonia, bromide, and hydrogen peroxide on bromate formation during water ozonation.

Ozone is widely applied for disinfection in drinking water treatment and the disinfection by-product bromate would be produced during the ozonation of bromide-bearing water. Hydrogen peroxide (H2O2) addition could effectively control the formation of bromate. However, the bromate depression performance would be impacted by water qualities. In this study, typical source water containing bromide in eastern China was selected to investigate bromate depression effect under different organic matter, ammonia and bromide concentrations during the H2O2-O3 process. The results display that organic matter, ammonia and bromide concentration could influence the formation of bromate significantly. As tyrosine was applied to increase the dissolved organic carbon (DOC) concentration of source water by 2.0 and 3.0 mg/L, the total concentration of bromate produced decreased gradually as the H2O2/O3 (g/g) doses increased from 0 to 1.0 and bromate concentration could be controlled below 10 µg/L as H2O2/O3 (g/g) was 0.5 and 1.0. As ammonia concentration increased by 0.1 and 0.5 mg/L, lower H2O2/O3 (g/g) doses would lead to an increase in bromate generation. As more H2O2 was added in water, the bromate formation would be suppressed. The increase of bromide concentration induced higher bromate formation. When the bromide concentration increased by 50 and 200 µg/L, bromate concentration was 10.7 µg/L and 41.2 µg/L respectively at the H2O2/O3 (g/g) of 1.0, higher than the standard level. As 200 µg/L of bromide was added to the water, bromate concentration increased significantly and then decreased as H2O2/O3 (g/g) increased and more H2O2 would be needed for bromate control.

Effects of process factors on the performance of electrochemical disinfection for wastewater in a continuous-flow cell reactor.

Although electrochemical disinfection has been shown to be an effective approach to inactivate bacteria in saline water, the effects of process parameters and reactor design for its application in low-salinity water have not been well understood. In this study, factorial experiments were performed to investigate the direct and confounded effects of applied current (5-20 mA), contact time (2.5-20 min), anode surface area (185-370 cm2), and chloride concentration (50-400 mg L-1) on the disinfection efficiency in fresh water and the secondary effluent of municipal wastewater. An electrochemical disinfection reactor cell with an internal volume of 75 cm3 was designed and fabricated. Residence time distribution analysis showed that the internal mixing of the reactor is similar to that of a dispersed plug-flow reactor. All studied process parameters showed significant effect on the kill efficiency, with the applied current and contact time having the most dominant effect. Although the effect of chloride concentration, which is responsible for electrochemical production of free chlorine in water, is statistically significant, it is not as prominent as those reported for high salinity water. A synergistic effect between chloride concentration and anode surface area was identified, leading to high kill efficiency (99.9%, 3 log kill) at low current density (0.0135 mA cm-2). Response surface modeling results suggested that a scaled-up disinfection reactor can be designed using large anode surface area with long contact time for high chloride water (400 mg L-1) or high current density with short contact time for low chloride water (50 mg L-1). The power requirement of a portable system treating 37.85 m3 day-1 (10,000 gpd) of municipal wastewater was estimated to be 1.9 to 8.3 kW to achieve a 3 log kill, depending on the reactor design.