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The human blood-brain barrier (BBB) comprises a single layer of brain microvascular endothelial cells (HBMECs) protecting the brain from bloodborne pathogens. Meningitis is among the most serious diseases, but the mechanisms by which major meningitis-causing bacterial pathogens cross the BBB to reach the brain remain poorly understood. We found that Streptococcus pneumoniae, group B Streptococcus, and neonatal meningitis Escherichia coli commonly exploit a unique vesicle fusion mechanism to hitchhike on transferrin receptor (TfR) transcytosis to cross the BBB and illustrated the details of this process in human BBB model in vitro and mouse model. Toll-like receptor signals emanating from bacteria-containing vesicles (BCVs) trigger K33-linked polyubiquitination at Lys168 and Lys181 of the innate immune regulator TRAF3 and then activate the formation of a protein complex containing the guanine nucleotide exchange factor RCC2, the small GTPase RalA and exocyst subcomplex I (SC I) on BCVs. The distinct function of SEC6 in SC I, interacting directly with RalA on BCVs and the SNARE protein SNAP23 on TfR vesicles, tethers these two vesicles and initiates the fusion. Our results reveal that innate immunity triggers a unique modification of TRAF3 and the formation of the HBMEC-specific protein complex on BCVs to authenticate the precise recognition and selection of TfR vesicles to fuse with and facilitate bacterial penetration of the BBB.
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Barrera Hematoencefálica , Células Endoteliales , Humanos , Animales , Ratones , Recién Nacido , Factor 3 Asociado a Receptor de TNF , Transcitosis , Bacterias , Receptores de TransferrinaRESUMEN
Microbial remediation of heavy metal polluted environment is ecofriendly and cost effective. Therefore, in the present study, Shewanella putrefaciens stain 4H was previously isolated by our group from the activated sludge of secondary sedimentation tank in a dyeing wastewater treatment plant. The bacterium was able to reduce chromate effectively. The strains showed significant ability to reduce Cr(VI) in the pH range of 8.0 to 10.0 (optimum pH 9.0) and 25-42 â (optimum 30 â) and were able to reduce 300 mg/L of Cr(VI) in 72 h under parthenogenetic anaerobic conditions. In this paper, the complete genome sequence was obtained by Nanopore sequencing technology and analyzed chromium metabolism-related genes by comparative genomics The genomic sequence of S. putrefaciens 4H has a length of 4,631,110 bp with a G + C content of 44.66% and contains 4015 protein-coding genes and 3223, 2414, 2343 genes were correspondingly annotated into the COG, KEGG, and GO databases. The qRT-PCR analysis showed that the expression of chrA, mtrC, and undA genes was up-regulated under Cr(VI) stress. This study explores the Chromium Metabolism-Related Genes of S. putrefaciens 4H and will help to deepen our understanding of the mechanisms of Cr(VI) tolerance and reduction in this strain, thus contributing to the better application of S. putrefaciens 4H in the field of remediation of chromium-contaminated environments.
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Shewanella putrefaciens , Shewanella putrefaciens/genética , Shewanella putrefaciens/metabolismo , Oxidación-Reducción , Cromo/toxicidad , Cromo/metabolismo , Bacterias/metabolismoRESUMEN
Bacterial chemoreceptors sense the extracellular signals and regulate bacterial motilities, biofilm formation, etc. The periplasmic ligand binding domains of chemoreceptors occur as different structural folds and recognize a diversity of chemical molecules. In Pseudomonas aeruginosa (PAO1), two bacterial chemoreceptors, McpN (PA2788) and PilJ (PA0411), are proposed to both contain a PilJ-like ligand-binding domain (LBD) (Pfam motif PF13675) and involved in nitrate chemotaxis and type IV pilus-mediated motility, respectively. The LBDs of McpN and PilJ consist of 135 and 263 residues, respectively, and share very low sequence identity, suggesting they might occur as different structures. Here, we found that PilJ-LBD folded into an HBM module, the same as the sensor domains of McpS-LBD and TorS-LBD, but it differed from that of McpN-LBD. We also observed a trimer in SEC and AUC and proposed a trimeric model based on the crystal structure. Based on the sequence, we classified the Pfam containing McpN-LBD and PilJ-LBD into three classes: sPilJ (single PilJ) represented by McpN-LBD with only one PilJ domain, dPilJ (dual PilJ) that contained dual PilJ domains, and hPilJ (hybrid PilJ) that comprises of a PilJ domain and another non-PilJ domain. Our work indicates a significant structural difference between the ligand binding domains of PilJ and McpN and will help our further study on both kinds of chemoreceptors.
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Proteínas Bacterianas , Fimbrias Bacterianas , Proteínas Bacterianas/metabolismo , Ligandos , Fimbrias Bacterianas/metabolismo , Dominios Proteicos , Quimiotaxis , Bacterias/metabolismoRESUMEN
Excitation-contraction coupling in skeletal muscle myofibers depends upon Ca2+ release from the sarcoplasmic reticulum through the ryanodine receptor/Ca2+-release channel RyR1. The RyR1 contains â¼100 Cys thiols of which â¼30 comprise an allosteric network subject to posttranslational modification by S-nitrosylation, S-palmitoylation and S-oxidation. However, the role and function of these modifications is not understood. Although aberrant S-nitrosylation of multiple unidentified sites has been associated with dystrophic diseases, malignant hyperthermia and other myopathic syndromes, S-nitrosylation in physiological situations is reportedly specific to a single (1 of â¼100) Cys in RyR1, Cys3636 in a manner gated by pO2. Using mice expressing a form of RyR1 with a Cys3636âAla point mutation to prevent S-nitrosylation at this site, we showed that Cys3636 was the principal target of endogenous S-nitrosylation during normal muscle function. The absence of Cys3636 S-nitrosylation suppressed stimulus-evoked Ca2+ release at physiological pO2 (at least in part by altering the regulation of RyR1 by Ca2+/calmodulin), eliminated pO2 coupling, and diminished skeletal myocyte contractility in vitro and measures of muscle strength in vivo. Furthermore, we found that abrogation of Cys3636 S-nitrosylation resulted in a developmental defect reflected in diminished myofiber diameter, altered fiber subtypes, and altered expression of genes implicated in muscle development and atrophy. Thus, our findings establish a physiological role for pO2-coupled S-nitrosylation of RyR1 in skeletal muscle contractility and development and provide foundation for future studies of RyR1 modifications in physiology and disease.
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Músculo Esquelético , Canal Liberador de Calcio Receptor de Rianodina , Canal Liberador de Calcio Receptor de Rianodina/metabolismo , Canal Liberador de Calcio Receptor de Rianodina/genética , Animales , Músculo Esquelético/metabolismo , Ratones , Calcio/metabolismo , Cisteína/metabolismo , Procesamiento Proteico-Postraduccional , Desarrollo de Músculos , Ratones Transgénicos , Señalización del CalcioRESUMEN
Aqueous all-iron redox flow batteries (RFBs) are promising competitors for next-generation grid-scale energy storage applications. However, the high-performance operation of all-iron RFBs in a wider temperature range is greatly hindered by inferior iron plating/stripping reaction and low solid-liquid transition temperature at Fe anode. Herein, a universal electrolyte additive design strategy for all-iron RFBs is reported, which realizes a highly reversible and dendrite-free Fe anode at low temperatures. Quantum chemistry calculations first screen several organic molecules with oxygen-containing functional groups and identify N,N-Dimethylacetmide (DMAc) as a potential candidate with low cost, high solubility, and strong interactions with Fe2+ and H2 O. Combined experimental characterizations and theoretical calculations subsequently demonstrate that adding DMAc into the FeCl2 solution effectively reshapes the primary solvation shell of Fe2+ via the Fe2+ -O (DMAc) bond and breaks hydrogen-bonding network of water through intensified H-bond interaction between DMAc and H2 O, thereby affording the Fe anode with enhanced Fe/Fe2+ reversibility and lower freezing point. Consequently, the assembled all-iron RFB achieves an excellent combination of high power density (25 mW cm-2 ), long charge-discharge cycling stability (95.59% capacity retention in 103 h), and preeminent battery efficiency at -20 °C (95% coulombic efficiency), which promise a future for wider temperature range operation of all-iron RFBs.
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OBJECTIVE: To assess the efficacy and safety of FDA-approved KRASG12C inhibitors in patients with KRASG12C-mutated solid tumors. METHODS: We searched PubMed, EMBASE, Cochrane Library, and major international conferences for clinical trials published in English up to March 6, 2023. Clinical trials investigating sotorasib or adagrasib and reporting the clinical outcomes of the objective response rate (ORR), disease control rate (DCR), or incidence rate of grade ≥ 3 adverse events (AEs) were eligible. The primary endpoint was the ORR. Secondary endpoints included the DCR, incidence rate of grade ≥ 3 AEs, and odds ratio (OR) of the ORR between patients with or without co-mutation. The Random-effects model was applied for the outcomes of interest. RESULTS: 18 studies with 1224 patients were included in this meta-analysis. The pooled ORR, DCR, and incidence rate of grade ≥ 3 AEs were 31 % (95 % CI, 25-37 %), 86 % (95 % CI, 82-89 %), and 29 % (95 % CI, 23-36 %), respectively. KRASG12C-mutated NSCLC patients with a co-mutation of KEAP1 exhibited a worse ORR than those with wild-type KEAP1 (OR: 0.35, 95 % CI: 0.16-0.77). CONCLUSIONS: This study provided a comprehensive understanding of the efficacy and safety of KRASG12C inhibitors in treating solid tumors and identified KEAP1 mutation as a potential predictive biomarker of inferior response in patients treated with KRASG12C inhibitors. These findings may assist in the design of future clinical trials for identifying populations that may benefit from KRASG12C inhibitor treatment.
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Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Humanos , Proteína 1 Asociada A ECH Tipo Kelch , Proteínas Proto-Oncogénicas p21(ras) , Factor 2 Relacionado con NF-E2 , MutaciónRESUMEN
Many crucial components inside electronic devices are made from non-renewable, non-biodegradable, and potentially toxic materials, leading to environmental damage. Finding alternative green dielectric materials is mandatory to align with global sustainable goals. Carboxymethyl cellulose (CMC) is a bio-polymer derived from cellulose and has outstanding properties. Herein, citric acid, dextrin, and CMC based hydrogels are prepared, which are biocompatible and biodegradable and exhibit rubber-like mechanical properties, with Young modulus values of 0.89 MPa. Hence, thin film CMC-based hydrogel is explored as a suitable green high-k dielectric candidate for operation at low voltages, demonstrating a high dielectric constant of up to 78. These fabricated transistors reveal stable high capacitance (2090 nF cm-2) for ≈±3 V operation. Using a polyelectrolyte-type approach and poly-(2-vinyl anthracene) (PVAn) surface modification, this study demonstrates a thin dielectric layer (d ≈30 nm) with a small voltage threshold (Vth ≈-0.8 V), moderate transconductance (gm ≈65 nS), and high ON-OFF ratio (≈105). Furthermore, the dielectric layer exhibits stable performance under bias stress of ± 3.5 V and 100 cycles of switching tests. The modified CMC-based hydrogel demonstrates desirable performance as a green dielectric for low-voltage operation, further highlighting its biocompatibility.
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Carboximetilcelulosa de Sodio , Dextrinas , Hidrogeles , Dextrinas/química , Carboximetilcelulosa de Sodio/química , Hidrogeles/química , Hidrogeles/síntesis química , Materiales Biocompatibles/química , Tecnología Química VerdeRESUMEN
Emerging studies have indicated that abnormally expressed microRNAs (miRNAs) are related to the pathogenesis of cerebral ischemia. Nevertheless, the function of miR-26a in neuronal damage and microglial activation during cerebral infarction remains elusive. It was revealed that miR-26a was downregulated in oxygen-glucose deprivation (OGD)-treated microglia and neurons. Overexpressing miR-26a reduced the inflammatory reaction in BV2 cells and decreased neuronal apoptosis following OGD stimulation. miR-26a upregulation inactivated the TLR4/MyD88/NF-κB pathway and inhibited TREM1 expression. Repressing NF-κB phosphorylation inhibited the miR-26a level. As supported by the dual-luciferase reporter assay, TREM1 was directly targeted by miR-26a. Furthermore, a rat model of middle cerebral artery occlusion (MCAO) was built. We discovered that miR-26a improved cognitive, learning and motor functions and reduced cerebral edema in MCAO rats. Mechanistically, upregulating miR-26a reduced inflammation and neuronal apoptosis by mitigating the TREM1-TLR4/MyD88/NF-κB pathway in the MCAO rat model. Collectively, this study verified that the miR-26a-TREM1-TLR4/MyD88/NF-κB axis contributes to modulating OGD-mediated microglial activation and neuronal injury.
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Heterogeneous noble metal catalysts exhibit various functions. Although their redox functions have been extensively studied, we focused on their soft Lewis acid functions. Supported Au, Pt, and Pd catalysts electrophilically attack the π-electrons of soft bases such as alkynes, alkenes, and aromatic compounds to perform addition and substitution reactions. Hydroamination, intramolecular cyclization of alkynyl carboxylic acids, isomerization of allylic esters, vinyl exchange reactions, Wacker oxidation, and oxidative homocoupling of aromatics are introduced based on a discussion of the active species and reaction mechanisms. Furthermore, the adsorption of sulfur compounds, which are soft bases, onto the supported AuNPs is discussed. The adsorption and removal of 1,3-dimethyltrisulfane (DMTS), which is the compound responsible for the stale odor of "hine-ka" in alcoholic beverages, particularly Japanese sake, is described.
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Dysregulated S-nitrosylation of proteins characterizes a broad array of human disorders, but its role in disease etiology is not well understood. Two new studies (Durham et al., 2008; Bellinger et al., 2008) now show that hyper-S-nitrosylation of the ryanodine receptor calcium release channel (RyR1) in skeletal muscle disrupts calcium ion flux. This disruption underlies the impaired contractility and cellular damage of skeletal muscle during strenuous exercise and in a spectrum of congenital muscle disorders including malignant hyperthermia.
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Músculo Esquelético/metabolismo , Músculo Esquelético/patología , Animales , Calcio/metabolismo , Golpe de Calor/metabolismo , Humanos , Hipertermia Maligna/metabolismo , Nitrosación , Canal Liberador de Calcio Receptor de Rianodina/metabolismoRESUMEN
OPINION STATEMENT: Inflammatory myofibroblastic tumor (IMT), characterized by intermediate malignancy and a propensity for recurrence, has presented a formidable clinical challenge in diagnosis and treatment. Its pathological characteristics may resemble other neoplasms or reactive lesions, and the treatment was limited, taking chemotherapies as the only option for those inoperable. However, discovering anaplastic lymphoma kinase (ALK) protein expression in approximately 50% of IMT cases has shed light on a new diagnostic approach and application of targeted therapies. With the previous success of combating ALK+ non-small-cell lung cancers with ALK tyrosine kinase inhibitors (TKIs), crizotinib, a first-generation ALK-TKI, was officially approved by the U.S. Food and Drug Administration in 2020, to treat unresectable ALK+ IMT. After the approval of crizotinib, other ALK-TKIs, such as ceritinib, alectinib, brigatinib, and lorlatinib, have proven their efficacy on ALK+ IMT with sporadic case reports. The sequential treatments of targeted therapies in may provide the insight into the choice of ALK-TKIs in different lines of treatment for unresectable ALK+ IMT.
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Antineoplásicos , Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Humanos , Quinasa de Linfoma Anaplásico , Carcinoma de Pulmón de Células no Pequeñas/patología , Crizotinib/uso terapéutico , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/metabolismo , Proteínas Tirosina Quinasas Receptoras , Antineoplásicos/uso terapéutico , Inhibidores de Proteínas Quinasas/uso terapéutico , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Tirosina Quinasas , Inflamación/diagnóstico , Inflamación/tratamiento farmacológico , Inflamación/etiologíaRESUMEN
The removal of Cr(VI) and As(V) from aqueous solutions has been a worldwide concern. In this study, Typha biochar (FBC) with magnetic iron oxide was prepared by impregnating Typha with FeCl3 and performing pyrolysis, and the possible mechanism of Cr(VI) and As(V) removal was investigated by combining characterization means and adsorption experiments. The results showed that the modified Typha biochar is rich in pores and has the potential to eliminate Cr and As through processes such as exchange and reduction. The single molecule uptake capacities of FBC for Cr(VI) and As(V) were 32.82 and 21.56 mg g-1, respectively. The adsorption process is spontaneous heat absorption, and the adsorption results are also consistent with the proposed secondary kinetic model. FBC still had >60% removal efficiency in the second and third reuse of Cr(VI), indicating its good recyclability. Therefore, this study confirms that FBC can effectively remove both Cr(VI) and As(V).
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Typhaceae , Contaminantes Químicos del Agua , Compuestos Férricos , Cromo , Carbón Orgánico , Adsorción , Contaminantes Químicos del Agua/análisisRESUMEN
Saline and alkaline soils are a challenge for sustainable crop production. The use of organic and inorganic amendments is a common practice to increase the fertility of salt-affected soils that can trigger faster carbon (C) and nitrogen (N) cycling. We examined the effects of gypsum (Gyps), farm manure (Manure) and rice straw (Straw) on enzyme activities, organic matter mineralization and CO2 emissions in two salt-affected soils [Solonchak (saline); pH: 8, electrical conductivity (EC): 6.5, sodium adsorption ratio (SAR): 2.5, and Solonetz (alkaline sodic); pH: 8.9, EC: 1.6, SAR: 17]. Gypsum addition decreased soil pH up to 0.62 and 0.30 units, SAR 1.2 and 5.2 units, and EC 2.9 and 1.4 units in Solonchak and Solonetz, respectively. Dissolved organic C, microbial biomass C, dissolved organic N, mineral N (NO3- and NH4+), enzyme activities (urease, invertase, catalase, phosphatase, phenol-oxidase), alkali extractable phenols, and available phosphorous increased with the application of all amendments in both soils. Solonetz released more CO2 than Solonchak, whereas maximum CO2 emissions were common after manure application (3140 mg kg-1 in Solonchak, and 3890 mg kg-1 in Solonetz). We conclude that high SAR and low EC increase CO2 emissions through accelerated C and N cycling and manure decomposition in Solonetz soils.
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Oryza , Suelo , Suelo/química , Sulfato de Calcio , Estiércol , Dióxido de Carbono , Cloruro de Sodio , CarbonoRESUMEN
We present a state-of-the-art lattice QCD calculation of the pion and kaon light-cone distribution amplitudes (DAs) using large-momentum effective theory. The calculation is done at three lattice spacings a≈{0.06,0.09,0.12} fm and physical pion and kaon masses, with the meson momenta P_{z}={1.29,1.72,2.15} GeV. The result is nonperturbatively renormalized in a recently proposed hybrid scheme with self-renormalization, and extrapolated reliably to the continuum as well as the infinite momentum limit. We find a significant deviation of the pion and kaon DAs from the asymptotic form, and a large SU(3) flavor breaking effect in the kaon DA.
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BACKGROUND: Sepsis, a life-threatening organ dysfunction induced by infection, is a major public health problem. This study aimed to evaluate the frequency and mortality of sepsis, severe sepsis, and septic shock in China. METHODS: We Searched MEDLINE, Embase, PubMed, and Cochrane Library from 1 January 1992 to 1 June 2020 for studies that reported on the frequency and mortality of sepsis, severe sepsis, and septic shock conducted in China. Random effects models were performed to estimate the pooled frequency and mortality of sepsis, severe sepsis, and septic shock. RESULTS: Our search yielded 846 results, of which 29 studies were included in this review. The pooled frequency of sepsis was estimated at 33.6% (95% CI 25.9% to 41.3%, I2 = 99.2%; p < 0.001), and the pooled mortality of sepsis, severe sepsis and septic shock were 29.0% (95% CI 25.3%-32.8%, I2 = 92.1%; p = 0), 31.1% (95% CI 25.3% to 36.9%, I2 = 85.8%; p < 0.001) and 37.3% (95% CI 28.6%-46.0%, I2 = 93.5%; p < 0.001). There was significant heterogeneity between studies. With a small number of included studies and the changing definition of sepsis, trends in sepsis frequency and mortality were not sufficient for analysis. Epidemiological data on sepsis in the emergency department (ED) are severely lacking, and more research is urgently needed in this area is urgently needed. CONCLUSIONS: Our findings indicated that the frequency and mortality of sepsis and septic shock in China were much higher than North America and Europe countries. Based on our results, an extremely high incidence and mortality of sepsis and septic shock in China's mainland requires more healthcare budget support. Epidemiological data on sepsis and septic shock in ED are severely lacking, and more research is urgently needed in this area. Trial registration This systematic review was conducted according to the statement of the preferred reporting items for systematic review (PROSPERO CRD42021243325) and the meta-analysis protocols (PRISMA-P).
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Sepsis , Choque Séptico , Humanos , China/epidemiología , Sepsis/epidemiología , Choque Séptico/epidemiologíaRESUMEN
Biochar is an excellent support material for heterogeneous catalyst in Fenton reaction. However, fabrication of heterogeneous catalyst supported by biochar normally adopts chemical impregnation which is costly and difficult in post-treatment. Here, impregnation by bioleaching driven by Acidithiobacillus ferrooxidans was developed. Bioleaching was particularly effective in loading iron to biochar. Iron loading amount was 225.5 mg/g after 10-g biochar was treated in bioleaching containing 40-g FeSO4·7H2O for 60 h. When copper was added into bioleaching, simultaneous impregnation with iron and copper could be achieved. Impregnation mechanism for iron was jarosite formation on biochar surface and adsorption for copper. For the high metal content, after pyrolysis, the final composites could activate hydrogen peroxide to decolorize dye effectively. With 15 mg as-synthesized Cu-Fe@biochar containing 254.3 mg/g iron and 33.4 mg/g copper, 50 mg/L reactive red 3BS or methylene blue could be decolorized completely in 20 min in a 100-mL solution by 16-mM H2O2 at pH 2.5. Compared with existing impregnation methods, bioleaching was facile, cheap and green, and deserved more concern. KEY POINTS: ⢠High amount of Fe is loaded to biochar uniformly as jarosite by bioleaching. ⢠Cu is adsorbed onto biochar during bioleaching. ⢠Synthesized Cu-Fe@biochar is an excellent photo-Fenton catalyst.
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Carbón Orgánico , Peróxido de Hidrógeno , Catálisis , Carbón Orgánico/química , Cobre , Oxidación-ReducciónRESUMEN
We present the first lattice QCD calculation of the distribution amplitudes of longitudinally and transversely polarized vector mesons K^{*} and Ï using large momentum effective theory. We use the clover fermion action on three ensembles with 2+1+1 flavors of highly improved staggered quarks action, generated by the MIMD Lattice Computation Collaboration, at physical pion mass and {0.06,0.09,0.12} fm lattice spacings and choose three different hadron momenta P_{z}={1.29,1.72,2.15} GeV. The resulting lattice matrix elements are nonperturbatively renormalized in a recently proposed hybrid scheme. An extrapolation to the continuum and infinite momentum limit is carried out. We find that, while the longitudinal distribution amplitudes tend to be close to the asymptotic form, the transverse ones deviate rather significantly from the asymptotic form. Our final results provide crucial ab initio theory inputs for analyzing pertinent exclusive processes.
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Surface modification with small-molecule zwitterions is experimentally proved to be an effective solution to improve the antifouling performance of polyamide membranes. However, there is no comprehensive understanding of their microscopic mechanism. In order to address this issue, in this work we constructed two atomistic models, PA (a pure polyamide membrane) and QDAP-PA (a polyamide membrane surface-modified with QDAP), where QDAP was a zwitterion that was prepared by 2,6-daaminopyridine quaternized with 3-bromopropionic acid experimentally. Density functional theory was adopted to elucidate the variations in the electrostatic potential before and after modification. Then, equilibrium molecular dynamics (EMD) simulations were conducted to investigate the structure and hydrophobic/hydrophilic nature of the membrane surface in the two models. Finally, we introduced two typical organic foulants, sodium dodecyl sulfonate (SDS) and dodecyl trimethyl ammonium chloride (DTAC), to evaluate the antifouling performance of the membranes with the umbrella sampling method. The analyses of the membrane structure and properties show that surface modification with small-molecule zwitterions can densify the membrane surface as well as enlarge the distribution of electrostatic potential on the membrane surface. Water molecules tend to have more interactions with the membrane and more hydrogen bonds near the membrane surface are observed in QDAP-PA. The antifouling test supports that QDAP-PA shows a better antifouling performance, as the surface-modified membrane exhibits a stronger resistance to SDS and DTAC. Even if the foulant is adsorbed to the membrane surface, the denser interface region can prevent a further pollution of the foulant. Also, the free energy needed during the process for QDAP-PA to desorb a foulant is relatively small, indicating that this kind of membrane is easy to clean. The current work might provide a comprehensive understanding of the enhanced fouling resistance of polyamide membranes after surface modification with small-molecule zwitterions.
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The transverse-momentum-dependent (TMD) soft function is a key ingredient in QCD factorization of Drell-Yan and other processes with relatively small transverse momentum. We present a lattice QCD study of this function at moderately large rapidity on a 2+1 flavor CLS dynamic ensemble with a=0.098 fm. We extract the rapidity-independent (or intrinsic) part of the soft function through a large-momentum-transfer pseudoscalar meson form factor and its quasi-TMD wave function using leading-order factorization in large-momentum effective theory. We also investigate the rapidity-dependent part of the soft function-the Collins-Soper evolution kernel-based on the large-momentum evolution of the quasi-TMD wave function.
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CNT-based reverse osmosis membranes have long been regarded as one of the most promising candidates for water desalination. However, it is a pity that there is no complete understanding of the exact role of CNTs in those nanocomposite membranes. To address this issue, three atomistic models of PA (pure polyamide membrane), PA-CNT1 (polyamide nanocomposite membrane with an embedded carbon nanotube oriented vertical to the membrane surface) and PA-CNT2 (polyamide nanocomposite with an embedded carbon nanotube oriented parallel to the membrane surface) were constructed respectively in this work. Then, equilibrium molecular dynamics (EMD) and non-equilibrium molecular dynamics (NEMD) simulations were conducted to investigate the structure and water dynamics in these three models. The EMD simulations revealed a better stacking of the PA matrix due to the addition of the CNT and this impact was more significant in PA-CNT1 than in PA-CNT2. Meanwhile, PA matrix near the mouth of the CNT was found to behave as an obstruction that hindered the exchange of water molecules inside and outside the CNT. In NEMD simulations, we found that water molecules were guided away from the CNT because of the better stacked surrounding PA matrix. The partially covered CNT might not help to increase water flux in PA-CNT1 while guided water molecules and the smaller polymer region afftected by the CNT contributed to a relatively high flux in PA-CNT2. The current work might serve as a comprehensive understanding of the role of CNTs in the reverse osmosis process.