ABSTRACT
Knudson's "two-hit" paradigm posits that carcinogenesis requires inactivation of both copies of an autosomal tumor suppressor gene. Here, we report that the glycolytic metabolite methylglyoxal (MGO) transiently bypasses Knudson's paradigm by inactivating the breast cancer suppressor protein BRCA2 to elicit a cancer-associated, mutational single-base substitution (SBS) signature in nonmalignant mammary cells or patient-derived organoids. Germline monoallelic BRCA2 mutations predispose to these changes. An analogous SBS signature, again without biallelic BRCA2 inactivation, accompanies MGO accumulation and DNA damage in Kras-driven, Brca2-mutant murine pancreatic cancers and human breast cancers. MGO triggers BRCA2 proteolysis, temporarily disabling BRCA2's tumor suppressive functions in DNA repair and replication, causing functional haploinsufficiency. Intermittent MGO exposure incites episodic SBS mutations without permanent BRCA2 inactivation. Thus, a metabolic mechanism wherein MGO-induced BRCA2 haploinsufficiency transiently bypasses Knudson's two-hit requirement could link glycolysis activation by oncogenes, metabolic disorders, or dietary challenges to mutational signatures implicated in cancer evolution.
Subject(s)
BRCA2 Protein , Breast Neoplasms , Glycolysis , Pyruvaldehyde , Animals , BRCA2 Protein/metabolism , BRCA2 Protein/genetics , Mice , Humans , Female , Pyruvaldehyde/metabolism , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Haploinsufficiency , Pancreatic Neoplasms/metabolism , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/pathology , Mutation , DNA Damage , DNA Repair , Cell Line, TumorABSTRACT
Antibodies are immunoglobulins that play essential roles in immune systems. All antibodies are glycoproteins that carry at least one or more conserved N-linked oligosaccharides (N-glycans) at the Fc domain. Many studies have demonstrated that both the presence and fine structures of the attached glycans can exert a profound impact on the biological functions and therapeutic efficacy of antibodies. However, antibodies usually exist as mixtures of heterogeneous glycoforms that are difficult to separate in pure glycoforms. Recent progress in glycoengineering has provided useful methods that enable production of glycan-defined and site-selectively modified antibodies for functional studies and for improved therapeutic efficacy. This review highlights major approaches in glycoengineering of antibodies with a focus on recent advances in three areas: glycoengineering through glycan biosynthetic pathway manipulation, glycoengineering through in vitro chemoenzymatic glycan remodeling, and glycoengineering of antibodies for site-specific antibody-drug conjugation.
Subject(s)
Antibodies/metabolism , Protein Engineering/methods , Animals , Antibodies/chemistry , Glycoproteins , Glycosylation , HumansABSTRACT
Influenza viruses infect 5-30% of the world's population annually, resulting in millions of incidents of hospitalization and thousands of mortalities worldwide every year. Although annual vaccination has significantly reduced hospitalization rates in vulnerable populations, the current vaccines are estimated to offer a wide range of protection from 10 to 60% annually. Such incomplete immunity may be related to both poor antigenic coverage of circulating strains, as well as to the insufficient induction of protective immunity. Beyond the role of hemagglutinin (HA) and neuraminidase (NA), vaccine-induced Abs have the capacity to induce a broader array of Ab effector functions, including Ab-dependent cellular cytotoxicity, that has been implicated in universal immunity against influenza viruses. However, whether different vaccine platforms can induce functional humoral immunity in a distinct manner remains incompletely defined. In this study, we compared vaccine-induced humoral immune responses induced by two seasonal influenza vaccines in Homo sapiens, the i.m. inactivated vaccine (IIV/Fluzone) and the live attenuated mucosal vaccine (LAIV/FluMist). Whereas the inactivated influenza vaccine induced superior Ab titers and FcγR binding capacity to diverse HA and NA Ags, the live attenuated influenza mucosal vaccine induced a more robust functional humoral immune response against both the HA and NA domains. Multivariate Ab analysis further highlighted the significantly different overall functional humoral immune profiles induced by the two vaccines, marked by differences in IgG titers, FcR binding, and both NK cell-recruiting and opsonophagocytic Ab functions. These results highlight the striking differences in Ab Fc-effector profiles induced systemically by two distinct influenza vaccine platforms.
Subject(s)
Influenza Vaccines , Influenza, Human , Orthomyxoviridae , Humans , Immunity, Humoral , Seasons , Vaccination , Hemagglutinins , Vaccines, Attenuated , Vaccines, Inactivated , Antibodies, ViralABSTRACT
Selective autophagy mediates specific degradation of unwanted cytoplasmic components to maintain cellular homeostasis. The suppressor of gene silencing 3 (SGS3) and RNA-dependent RNA polymerase 6 (RDR6)-formed bodies (SGS3/RDR6 bodies) are essential for siRNA amplification in planta. However, whether autophagy receptors regulate selective turnover of SGS3/RDR6 bodies is unknown. By analyzing the transcriptomic response to virus infection in Arabidopsis, we identified a virus-induced small peptide 1 (VISP1) composed of 71 amino acids, which harbor a ubiquitin-interacting motif that mediates interaction with autophagy-related protein 8. Overexpression of VISP1 induced selective autophagy and compromised antiviral immunity by inhibiting SGS3/RDR6-dependent viral siRNA amplification, whereas visp1 mutants exhibited opposite effects. Biochemistry assays demonstrate that VISP1 interacted with SGS3 and mediated autophagic degradation of SGS3/RDR6 bodies. Further analyses revealed that overexpression of VISP1, mimicking the sgs3 mutant, impaired biogenesis of endogenous trans-acting siRNAs and up-regulated their targets. Collectively, we propose that VISP1 is a small peptide receptor functioning in the crosstalk between selective autophagy and RNA silencing.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/genetics , Arabidopsis/immunology , Peptides/genetics , RNA-Dependent RNA Polymerase/metabolism , Arabidopsis/metabolism , Arabidopsis/virology , Arabidopsis Proteins/genetics , Autophagosomes/physiology , Autophagy/physiology , Autophagy-Related Protein 8 Family/metabolism , Gene Expression Regulation, Plant , Mutation , Peptides/metabolism , Plant Immunity , Plants, Genetically Modified , RNA, Small Interfering , RNA-Dependent RNA Polymerase/genetics , Nicotiana/geneticsABSTRACT
Sepsis arises from an uncontrolled inflammatory response triggered by infection or stress, accompanied by alteration in cellular energy metabolism, and a strong correlation exists between these factors. Alpha-ketoglutarate (α-KG), an intermediate product of the TCA cycle, has the potential to modulate the inflammatory response and is considered a crucial link between energy metabolism and inflammation. The scavenger receptor (SR-A5), a significant pattern recognition receptor, assumes a vital function in anti-inflammatory reactions. In the current investigation, we have successfully illustrated the ability of α-KG to mitigate inflammatory factors in the serum of septic mice and ameliorate tissue damage. Additionally, α-KG has been shown to modulate metabolic reprogramming and macrophage polarization. Moreover, our findings indicate that the regulatory influence of α-KG on sepsis is mediated through SR-A5. We also elucidated the mechanism by which α-KG regulates SR-A5 expression and found that α-KG reduced the N6-methyladenosine level of macrophages by up-regulating the m6A demethylase ALKBH5. α-KG plays a crucial role in inhibiting inflammation by regulating SR-A5 expression through m6A demethylation during sepsis. The outcomes of this research provide valuable insights into the relationship between energy metabolism and inflammation regulation, as well as the underlying molecular regulatory mechanism.
ABSTRACT
Signaling by the evolutionarily conserved mitogen-activated protein kinase or extracellular signal-regulated kinase (MAPK/ERK) plays critical roles in converting extracellular stimuli into immune responses. However, whether MAPK/ERK signaling induces virus immunity by directly phosphorylating viral effectors remains largely unknown. Barley yellow striate mosaic virus (BYSMV) is an economically important plant cytorhabdovirus that is transmitted by the small brown planthopper (SBPH, Laodelphax striatellus) in a propagative manner. Here, we found that the barley (Hordeum vulgare) MAPK MPK3 (HvMPK3) and the planthopper ERK (LsERK) proteins interact with the BYSMV nucleoprotein (N) and directly phosphorylate N protein primarily on serine 290. The overexpression of HvMPK3 inhibited BYSMV infection, whereas barley plants treated with the MAPK pathway inhibitor U0126 displayed greater susceptibility to BYSMV. Moreover, knockdown of LsERK promoted virus infection in SBPHs. A phosphomimetic mutant of the N Ser290 (S290D) completely abolished virus infection because of impaired self-interaction of BYSMV N and formation of unstable N-RNA complexes. Altogether, our results demonstrate that the conserved MAPK and ERK directly phosphorylate the viral nucleoprotein to trigger immunity against cross-kingdom infection of BYSMV in host plants and its insect vectors.
Subject(s)
Hemiptera , Hordeum , Rhabdoviridae , Animals , Antiviral Agents , Hordeum/genetics , Insect Vectors , Nucleoproteins/genetics , Rhabdoviridae/physiologyABSTRACT
An interplay of geometrical frustration and strong quantum fluctuations in a spin-1/2 triangular-lattice antiferromagnet (TAF) can lead to exotic quantum states. Here, we report the neutron-scattering, magnetization, specific heat, and magnetocaloric studies of the recently discovered spin-1/2 TAF Na2BaCo(PO4)2, which can be described by a spin-1/2 easy axis XXZ model. The zero-field neutron diffraction experiment reveals an incommensurate antiferromagnetic ground state with a significantly reduced ordered moment of about 0.54(2) µB/Co. Different magnetic phase diagrams with magnetic fields in the ab plane and along the easy c-axis were extracted based on the magnetic susceptibility, specific heat, and elastic neutron-scattering results. In addition, two-dimensional (2D) spin dispersion in the triangular plane was observed in the high-field polarized state, and microscopic exchange parameters of the spin Hamiltonian have been determined through the linear spin wave theory. Consistently, quantum critical behaviors with the universality class of dâ=â2 and νz = 1 were established in the vicinity of the saturation field, where a Bose-Einstein condensation (BEC) of diluted magnons occurs. The newly discovered quantum criticality and fractional magnetization phase in this ideal spin-1/2 TAF present exciting opportunities for exploring exotic quantum phenomena.
ABSTRACT
The inhibition of cell surface crystal adhesion and an appropriate increase in crystal endocytosis contribute to the inhibition of kidney stone formation. In this study, we investigated the effects of different degrees of carboxymethylation on these processes. An injury model was established by treating human renal proximal tubular epithelial (HK-2) cells with 98.3 ± 8.1 nm calcium oxalate dihydrate (nanoCOD) crystals. The HK-2 cells were protected with carboxy (-COOH) Desmodium styracifolium polysaccharides at 1.17% (DSP0), 7.45% (CDSP1), 12.2% (CDSP2), and 17.7% (CDSP3). Changes in biochemical indexes and effects on nanoCOD adhesion and endocytosis were detected. The protection of HK-2 cells from nanoCOD-induced oxidative damage by carboxymethylated Desmodium styracifolium polysaccharides (CDSPs) is closely related to the protection of subcellular organelles, such as mitochondria. CDSPs can reduce crystal adhesion on the cell surface and maintain appropriate crystal endocytosis, thereby reducing the risk of kidney stone formation. CDSP2 with moderate -COOH content showed the strongest protective activity among the CDSPs.
Subject(s)
Calcium Oxalate , Endocytosis , Kidney Calculi , Polysaccharides , Humans , Calcium Oxalate/metabolism , Cell Adhesion/drug effects , Cell Line , Crystallization , Endocytosis/drug effects , Epithelial Cells/drug effects , Epithelial Cells/metabolism , Epithelial Cells/pathology , Kidney Calculi/prevention & control , Kidney Calculi/drug therapy , Kidney Tubules, Proximal/drug effects , Kidney Tubules, Proximal/pathology , Kidney Tubules, Proximal/metabolism , Oxidative Stress/drug effects , Polysaccharides/pharmacology , Polysaccharides/chemistry , Cell Survival/drug effects , Cell Cycle/drug effects , Calcium/metabolism , Intracellular Space/metabolism , Reactive Oxygen Species/metabolism , Membrane Potential, Mitochondrial/drug effectsABSTRACT
Lithium-sulfur batteries (LSBs) are facing many challenges, such as the inadequate conductivity of sulfur, the shuttle effect caused by lithium polysulfide (LiPSs), lithium dendrites, and the flammability, which have hindered their commercial applications. Herein, a "four-in-one" functionalized coating is fabricated on the surface of polypropylene (PP) separator by using a novel flame-retardant namely InC-HCTB to meet these challenges. InC-HCTB is obtained by cultivating polyphosphazene on the surface of carbon nanotubes with an in situ growth strategy. First, this unique architecture fosters an enhanced conductive network, bolstering the bidirectional enhancement of both ionic and electronic conductivities. Furthermore, InC-HCTB effectively inhibits the shuttle effect of LiPSs. LSBs exhibit a remarkable capacity of 1170.7 mA h g-1 at 0.2 C, and the capacity degradation is a mere 0.0436% over 800 cycles at 1 C. Third, InC-HCTB coating serves as an ion migration network, hindering the growth of lithium dendrites. More importantly, InC-HCTB exhibits notable flame retardancy. The radical trapping action in the gas phase and the protective effect of the shielded char layer in the condensed phase are simulated and verified. This facile in situ growth strategy constructs a "four-in-one" functional separator coating, rendering InC-HCTB a promising additive for the large-scale production of safe and stable LSBs.
ABSTRACT
Ultralow thermal conductivity and fast ionic diffusion endow superionic materials with excellent performance both as thermoelectric converters and as solid-state electrolytes. Yet the correlation and interdependence between these two features remain unclear owing to a limited understanding of their complex atomic dynamics. Here we investigate ionic diffusion and lattice dynamics in argyrodite Ag8SnSe6 using synchrotron X-ray and neutron scattering techniques along with machine-learned molecular dynamics. We identify a critical interplay of the vibrational dynamics of mobile Ag and a host framework that controls the overdamping of low-energy Ag-dominated phonons into a quasi-elastic response, enabling superionicity. Concomitantly, the persistence of long-wavelength transverse acoustic phonons across the superionic transition challenges a proposed 'liquid-like thermal conduction' picture. Rather, a striking thermal broadening of low-energy phonons, starting even below 50 K, reveals extreme phonon anharmonicity and weak bonding as underlying features of the potential energy surface responsible for the ultralow thermal conductivity (<0.5 W m-1 K-1) and fast diffusion. Our results provide fundamental insights into the complex atomic dynamics in superionic materials for energy conversion and storage.
ABSTRACT
The prompt initiation of antiviral therapy is essential in patients with chronic hepatitis B (CHB), especially when severe liver inflammation is detected. However, transcutaneous liver puncture, the gold standard for assessing liver inflammation, is invasive and its widespread application is limited. Therefore, there is an urgent need for more non-invasive markers to predict liver inflammation. In our retrospective cross-sectional study, which included 120 CHB patients and 31 healthy subjects, we observed a significant increase in serum chemokine C-X-C-motif ligand 16 (CXCL16) in CHB patients compared to healthy controls (p < .001). Notably, patients with severe inflammation (Scheuer's grade G ≥ 3, n = 26) exhibited a substantial increase in serum CXCL16 compared to those with non-severe inflammation (Scheuer's grade G < 3, n = 96) [(median, IQR), 0.42 (0.24-0.71) ng/mL vs. 1.01 (0.25-2.09) ng/mL, p < .001]. Furthermore, we developed a predictive model that combined CXCL16 with platelet count (PLT), alanine aminotransferase (ALT) and albumin (ALB) to accurately predict liver inflammation in CHB patients. This model was more effective than ALT alone in predicting liver inflammation (AUC, 0.92 vs. 0.81, p = .015). Additionally, using an HBV-transduced mouse model, we demonstrated that blocking CXCL16 led to a reduction in liver inflammation and impaired infiltration and function of natural killer T (NKT) and natural killer (NK) cells. These findings suggest that CXCL16 is a promising non-invasive biomarker of liver inflammation in CHB patients and may play a role in inducing liver inflammation via a NKT and NK cell pathway.
Subject(s)
Hepatitis B, Chronic , Hepatitis , Animals , Mice , Humans , Hepatitis B, Chronic/complications , Retrospective Studies , Cross-Sectional Studies , Hepatitis B virus , Inflammation , Hepatitis B e Antigens , Chemokine CXCL16ABSTRACT
Chronic hepatitis B virus (HBV) infection is a significant global public health concern, and the clearance of HBV is closely linked to the activity of HBV-specific T cells, which is regulated by various co-suppressor molecules. Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is among these co-suppressor molecules which induces T cell exhaustion by competitively inhibiting CD28 and dampening the function of HBV-specific T cells. CTLA-4 also plays a role in the regulation of T helper (Th) cell differentiation and influences cytokine release. In addition, CTLA-4 can impact glucose metabolism in hepatocellular carcinoma through its interaction with T regulatory (Treg) cells. This review aims to provide a comprehensive overview of the existing literature related to the role of CTLA-4 in HBV patients across different subsets of T cells. Additionally, we propose a discussion on the possible mechanisms through which CTLA-4 may contribute to HBV infection, as well as the development of HBV-induced cirrhosis and hepatocellular carcinoma.
ABSTRACT
BACKGROUND: The association of hepatitis B virus (HBV) DNA levels and liver fibrosis in chronic hepatitis B (CHB) patients with immune-tolerant phase remains unclear. We explored the association between liver fibrosis and HBV DNA levels in HBeAg-positive CHB patients with normal alanine transaminase (ALT) with relatively high HBV DNA. METHODS: Six hundred and twenty-two HBeAg-positive CHB patients with normal ALT were included. Patients were divided into three categories: low (6 log10 IU/mL ≤ HBV DNA < 7 log10 IU/mL), moderate (7 log10 IU/mL ≤ HBV DNA < 8 log10 IU/mL), and high (HBV DNA ≥ 8 log10 IU/mL). APRI, FIB-4, transient elastography, or liver biopsy were used to assess liver fibrosis. RESULTS: The median age of patients was 33.0 years and 57.9% patients were male. 18.8%, 52.1%, and 29.1% of patients had low, moderate, and high HBV DNA levels, respectively. The APRI (0.33 vs. 0.26 vs. 0.26, P < 0.001), FIB-4 (1.03 vs. 0.71 vs. 0.68, P < 0.001), and LSM values (7.6 kPa vs. 5.6 kPa vs. 5.5 kPa, P = 0.086) were higher in low HBV DNA group than other two groups. Low HBV DNA group had higher proportions of significant fibrosis (24.8% vs. 9.9% vs. 3.3%, P < 0.001) and cirrhosis (7.7% vs. 2.5% vs. 1.1%, P = 0.004) than moderate and high HBV DNA groups. Moderate (OR 3.095, P = 0.023) and low (OR 4.968, P = 0.003) HBV DNA were independent risk factors of significant fibrosis. CONCLUSION: Lower HBV DNA level was associated with more severe liver fibrosis in HBeAg-positive CHB patients with ALT.
Subject(s)
Alanine Transaminase , DNA, Viral , Hepatitis B e Antigens , Hepatitis B virus , Hepatitis B, Chronic , Liver Cirrhosis , Humans , Hepatitis B, Chronic/complications , Hepatitis B, Chronic/virology , Hepatitis B, Chronic/pathology , Hepatitis B, Chronic/blood , Male , Female , Adult , Liver Cirrhosis/virology , Liver Cirrhosis/blood , Liver Cirrhosis/pathology , DNA, Viral/blood , Alanine Transaminase/blood , Hepatitis B e Antigens/blood , Hepatitis B virus/genetics , Middle Aged , Viral Load , Young Adult , Liver/pathology , Liver/virology , BiopsyABSTRACT
The impact of mitochondrial dysfunction on the pathogenesis of cardiovascular disease is increasing. However, the precise underlying mechanism remains unclear. Mitochondria produce cellular energy through oxidative phosphorylation while regulating calcium homeostasis, cellular respiration, and the production of biosynthetic chemicals. Nevertheless, problems related to cardiac energy metabolism, defective mitochondrial proteins, mitophagy, and structural changes in mitochondrial membranes can cause cardiovascular diseases via mitochondrial dysfunction. Mitofilin is a critical inner mitochondrial membrane protein that maintains cristae structure and facilitates protein transport while linking the inner mitochondrial membrane, outer mitochondrial membrane, and mitochondrial DNA transcription. Researchers believe that mitofilin may be a therapeutic target for treating cardiovascular diseases, particularly cardiac mitochondrial dysfunctions. In this review, we highlight current findings regarding the role of mitofilin in the pathogenesis of cardiovascular diseases and potential therapeutic compounds targeting mitofilin.
Subject(s)
Cardiovascular Diseases , Mitochondrial Proteins , Muscle Proteins , Humans , Animals , Cardiovascular Diseases/metabolism , Cardiovascular Diseases/drug therapy , Muscle Proteins/metabolism , Muscle Proteins/genetics , Mitochondrial Proteins/metabolism , Mitochondria, Heart/metabolism , Mitochondria, Heart/drug effectsABSTRACT
Stroke was the fifth leading cause of death in the United States in 2021, and cost U.S. residents approximately $56.2 billion during 2019-2020. During 2006-2010, self-reported stroke prevalence among noninstitutionalized adults had a relative decrease of 3.7%. Data from the Behavioral Risk Factor Surveillance System were used to analyze age-standardized stroke prevalence during 2011-2022 among adults aged ≥18 years. From 2011-2013 to 2020-2022, overall self-reported stroke prevalence increased by 7.8% nationwide. Increases occurred among adults aged 18-64 years; females and males; non-Hispanic Black or African American (Black), non-Hispanic White (White), and Hispanic or Latino (Hispanic) persons; and adults with less than a college degree. Stroke prevalence was higher among adults aged ≥65 years than among younger adults; among non-Hispanic American Indian or Alaska Native, non-Hispanic Native Hawaiian or Pacific Islander, and Black adults than among White adults; and among adults with less than a high school education than among those with higher levels of education. Stroke prevalence decreased in the District of Columbia and increased in 10 states. Initiatives to promote knowledge of the signs and symptoms of stroke, and the identification of disparities in stroke prevalence, might help to focus clinical and programmatic interventions, such as the Million Hearts 2027 initiative or the Paul Coverdell National Acute Stroke Program, to improve prevention and treatment of stroke.
Subject(s)
Behavioral Risk Factor Surveillance System , Stroke , Humans , Male , Female , Middle Aged , United States/epidemiology , Adult , Adolescent , Prevalence , Stroke/epidemiology , Stroke/ethnology , Young Adult , AgedABSTRACT
PURPOSE: This study aimed to evaluate the impact of the diverse stent size selection on the clinical and angiographic outcomes of Willis covered stent (WCS) for the treatment of skull base cerebrovascular diseases. MATERIALS AND METHODS: A total of 147 patients with 151 skull base cerebrovascular diseases treated with WCS in 3 centers between January 2015 and July 2022 were included in this study. Several parameters depicting stent size and parent artery condition were incorporated into the analysis of the outcomes. RESULTS: Complete occlusion was found in 106 cases (68.2%) immediately after deployment and 126 cases (83.4%) after technical adjustment. In the multivariate logistics analysis, the difference between stent diameter and parent artery diameter (DD) was significantly associated with immediate endoleak without adjustment (odds ratio [OR]=0.410; p=0.005) and late endoleak (OR=0.275; p=0.028). In addition, differences between stent diameter and parent artery diameter at wide landing point (DSW) and differences between stent diameter and parent artery diameter at narrow landing point (DSN) was also was significant associated with immediate endoleak without adjustment and balloon re-dilation respectively. CONCLUSIONS: This study demonstrated that the diameter selection of the WCS was associated with the occurrence of endoleak during the treatment of skull base cerebrovascular diseases. Precise selection and evaluation of stent size and vessel condition were significant factors for skull base cerebrovascular diseases treated by WCS. CLINICAL IMPACT: This study demonstrates a significant association between the diameter selection of the Willis covered stent (WCS) and the occurrence of endoleak in the management of skull base cerebrovascular diseases. The results offer valuable medical evidence that can inform stent selection for WCS. The study emphasizes the significance of precise evaluation of stent size and vessel condition as crucial factors in WCS procedures. These findings underscore the importance of meticulous consideration and individualized approaches to stent selection, ultimately improving treatment outcomes in clinical practice.
ABSTRACT
Remediation of large and dilute plumes of groundwater contaminated by oxidized pollutants such as chromate is a common and difficult challenge. Herein, we show that in situ formation of FeS nanoparticles (using dissolved Fe(II), S(-II), and natural organic matter as a nucleating template) results in uniform coating of aquifer material to create a regenerable reactive zone that mitigates Cr(VI) migration. Flow-through columns packed with quartz sand are amended first with an Fe2+ solution and then with a HS- solution to form a nano-FeS coating on the sand, which does not hinder permeability. This nano-FeS coating effectively reduces and immobilizes Cr(VI), forming Fe(III)-Cr(III) coprecipitates with negligible detachment from the sand grains. Preconditioning the sand with humic or fulvic acid (used as model natural organic matter (NOM)) further enhances Cr(VI) sequestration, as NOM provides additional binding sites of Fe2+ and mediates both nucleation and growth of FeS nanoparticles, as verified with spectroscopic and microscopic evidence. Reactivity can be easily replenished by repeating the procedures used to form the reactive coating. These findings demonstrate that such enhancement of attenuation capacity can be an effective option to mitigate Cr(VI) plume migration and exposure, particularly when tackling contaminant rebound post source remediation.
Subject(s)
Chromium , Groundwater , Oxidation-Reduction , Water Pollutants, Chemical , Groundwater/chemistry , Chromium/chemistry , Water Pollutants, Chemical/chemistry , Nanoparticles/chemistry , Environmental Restoration and Remediation/methods , Humic Substances , Ferrous Compounds/chemistry , Benzopyrans/chemistryABSTRACT
Transition-metal dichalcogenides (TMDs) have shown great promise as selective and high-capacity sorbents for Hg(II) removal from water. Yet, their design should consider safe disposal of spent materials, particularly the subsequent formation of methylmercury (MeHg), a highly potent and bioaccumulative neurotoxin. Here, we show that microbial methylation of mercury bound to MoS2 nanosheets (a representative TMD material) is significant under anoxic conditions commonly encountered in landfills. Notably, the methylation potential is highly dependent on the phase compositions of MoS2. MeHg production was higher for 1T MoS2, as mercury bound to this phase primarily exists as surface complexes that are available for ligand exchange. In comparison, mercury on 2H MoS2 occurs largely in the form of precipitates, particularly monovalent mercury minerals (e.g., Hg2MoO4 and Hg2SO4) that are minimally bioavailable. Thus, even though 1T MoS2 is more effective in Hg(II) removal from aqueous solution due to its higher adsorption affinity and reductive ability, it poses a higher risk of MeHg formation after landfill disposal. These findings highlight the critical role of nanoscale surfaces in enriching heavy metals and subsequently regulating their bioavailability and risks and shed light on the safe design of heavy metal sorbent materials through surface structural modulation.
Subject(s)
Mercury , Methylation , Adsorption , Nanostructures/chemistry , Water Pollutants, Chemical/chemistry , Methylmercury Compounds , Molybdenum/chemistryABSTRACT
Zeolitic Imidazolate Frameworks-8 (ZIF-8) is commonly used as an ideal precursor for non-noble metal catalysts because of its high specific surface area, ultra-high porosity, and N-rich content. Upon pyrolyzing ZIF-8 at 900 °C in Ar, the resulting material, referred to as Z8, displayed good activity toward the oxygen reduction reaction (ORR). Then the ZIF-8 was mixed with various conductive carbon materials, such as multiwall carbon nanotubes (MWCNTs), Acetylene black (ACET), Vulcan XC-72R (XC-72R), and Ketjenblack EC-600JD (EC-600JD), to form Z8 composites. The Z8/MWCNTs composite exhibited enhanced ORR activity owing to its network structure, meso-/microporous hierarchical porous structure, improved electrical conductivity, and graphitization. Subsequently, iron and nitrogen co-doping is achieved through the pyrolysis of a mixture comprising Fe, N precursor, and ZIF-8/MWCNTs, which is denoted as FeN-Z8/MWCNTs. The intrinsically high electrical conductivity of MWCNTs facilitated efficient electron transfer during the ORR, while the meso-/microporous hierarchical porous structure and network structure of Fe, N co-doped ZIF-8/MWCNTs promoted oxygen transport. The presence of Fe-containing species in the catalyst acted as activity centers for ORR. This strategy of preparing Z8 composites and modifying them with Fe, N co-doping offers an insightful approach to designing cost-effective electrocatalysts.
ABSTRACT
This study tested phenotypic and biometric associations between physical and cognitive catch-up growth in a community sample of twins (n = 1285, 51.8% female, 89.3% White). Height and weight were measured at up to 17 time points between birth and 15 years, and cognitive ability was assessed at up to 16 time points between 3 months and 15 years. Weight and length at birth were positively associated with cognitive abilities in infancy and adolescence (r's = .16-.51). More rapid weight catch-up growth was associated with slower, steadier cognitive catch-up growth. Shared and nonshared environmental factors accounted for positive associations between physical size at birth and cognitive outcomes. Findings highlight the role of prenatal environmental experiences in physical and cognitive co-development.