Platinum nanoparticles (Pt NPs) with uniform size and high dispersion have been successfully assembled on poly(diallyldimethylammonium chloride) functionalized graphene oxide via a sodium borohydride ...reduction process. The loading concentration of Pt NPs on graphene can be adjusted in the range of 18–78 wt %. The obtained Pt/graphene nanocomposites are characterized by transmission electron microscopy, high resolution transmission electron microscopy, energy dispersive spectrometry, X-ray diffraction, and thermogravimetric analysis. The results show that the Pt NPs with sizes of approximate 4.6 nm uniformly disperse on graphene surface for all Pt loading densities. Electrochemical studies reveal that the Pt/graphene nanocomposites with electrochemically active surface area of 141.6 m2/g show excellent electrocatalytic activity toward methanol oxidation and oxygen reduction. The present method is promising for the synthesis of high performance catalysts for fuel cells, gas phase catalysis, and sensors.
The gut-brain axis is a bidirectional information interaction system between the central nervous system (CNS) and the gastrointestinal tract, in which gut microbiota plays a key role. The gut ...microbiota forms a complex network with the enteric nervous system, the autonomic nervous system, and the neuroendocrine and neuroimmunity of the CNS, which is called the microbiota-gut-brain axis. Due to the close anatomical and functional interaction of the gut-liver axis, the microbiota-gut-liver-brain axis has attracted increased attention in recent years. The microbiota-gut-liver-brain axis mediates the occurrence and development of many diseases, and it offers a direction for the research of disease treatment. In this review, we mainly discuss the role of the gut microbiota in the irritable bowel syndrome, inflammatory bowel disease, functional dyspepsia, non-alcoholic fatty liver disease, alcoholic liver disease, cirrhosis and hepatic encephalopathy via the gut-liver-brain axis, and the focus is to clarify the potential mechanisms and treatment of digestive diseases based on the further understanding of the microbiota-gut- liver-brain axis.
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•Zwitterionic COFs were designed and prepared for efficient uptake of fluoroquinolone antibiotics.•More functional binding sites were exposed after initial self-exfoliation to ionic ...covalent organic nanosheets.•Tp-MTABs with multiple binding sites exhibited ultrafast adsorption and superior adsorption capacity for FQs.•Zwitterionic Tp-MTABs showed splendid selectivity for the uptake of FQs in complex systems.•Plausible FQs adsorbed mechanisms were ion-pair binding and π–π interactions.
The effective removal of zwitterionic fluoroquinolone (FQ) antibiotics with high water solubility in wastewater is a key environmental challenge due to the inefficacy of conventional methods of wastewater treatment. In this work, zwitterionic covalent organic frameworks (Tp-MTABs) were synthesized through a solvothermal route using 5,5′,5″-methanetriyltris(2-aminobenzenesulfonic acid) (MTABs) as a zwitterionic linker and 1,3,5-triformylphloroglucinol (Tp) as neutral knots for efficient uptake of FQ antibiotics. Tp-MTABs compose of regular distributions of sulfonic acids and amines that produce zwitterionic binding sites, which produce complementary ion-pair interactions with zwitterionic FQ antibiotics. The charge on Tp-MTABs facilitates its initial self-exfoliation to few-layered ionic covalent organic nanosheets (iCONs) with controlled surface charge, which exposes more surface ionic sites and phenyl groups toward FQ antibiotics, improving ion-pair and π–π interactions between iCONs and FQ antibiotics. These iCONs with multiple active sites highly facilitated the process of antibiotics adsorption, boosting the adsorption kinetics and improving the selectivity towards FQ antibiotics. Tp-MTABs endows ultrafast adsorption rate (<30 s) of FQ antibiotics (average over 99%). In addition, Tp-MTABs exhibit high selectivity to the removal of FQs in complex systems containing multiple competing organic compounds and high-salinity natural seawater. This work explored the structural and functional design of iCONs for the removal of organic molecules in environmental remediation.
Chemotherapies are known often to induce severe gastrointestinal tract toxicity but the underlying mechanism re- mains unclear. This study considers the widely applied cytotoxic agent irinotecan ...（CPT-11） as a representative agent and demonstrates that treatment induces massive release of double-strand DNA from the intestine that accounts for the dose-limiting intestinal toxicity of the compound. Specifically, ＂self-DNA＂ released through exosome secretion en- ters the cytosol of innate immune cells and activates the AIM2 （absent in melanoma 2） inflammasome. This leads to mature IL-Iβ and IL-18 secretion and induces intestinal mucositis and late-onset diarrhoea. Interestingly, abrogation of AIM2 signalling, either in AIM2-deficient mice or by a pharmacological inhibitor such as thalidomide, significantly reduces the incidence of drug-induced diarrhoea without affecting the anticancer efficacy of CPT-11. These findings provide mechanistic insights into how chemotherapy triggers innate immune responses causing intestinal toxicity, and reveal new chemotherapy regimens that maintain anti-tumour effects but circumvent the associated adverse in- flammatory response.
Recently, increasing evidence has suggested the association between gut dysbiosis and Alzheimer's disease (AD) progression, yet the role of gut microbiota in AD pathogenesis remains obscure. Herein, ...we provide a potential mechanistic link between gut microbiota dysbiosis and neuroinflammation in AD progression. Using AD mouse models, we discovered that, during AD progression, the alteration of gut microbiota composition leads to the peripheral accumulation of phenylalanine and isoleucine, which stimulates the differentiation and proliferation of pro-inflammatory T helper 1 (Th1) cells. The brain-infiltrated peripheral Th1 immune cells are associated with the M1 microglia activation, contributing to AD-associated neuroinflammation. Importantly, the elevation of phenylalanine and isoleucine concentrations and the increase of Th1 cell frequency in the blood were also observed in two small independent cohorts of patients with mild cognitive impairment (MCI) due to AD. Furthermore, GV-971, a sodium oligomannate that has demonstrated solid and consistent cognition improvement in a phase 3 clinical trial in China, suppresses gut dysbiosis and the associated phenylalanine/isoleucine accumulation, harnesses neuroinflammation and reverses the cognition impairment. Together, our findings highlight the role of gut dysbiosis-promoted neuroinflammation in AD progression and suggest a novel strategy for AD therapy by remodelling the gut microbiota.
An odorous tap water crisis that affected two million residents for several days occurred in Wuxi, China in the summer of 2007. Volatile sulfide chemicals including methyl thiols, dimethyl sulfide, ...dimethyl disulfide, and dimethyl trisulfide were the dominant odorous contaminants in Lake Taihu and in tap water during the crisis. These contaminants originated from the decomposition of a massive cyanobacterial bloom that was triggered by illegal industrial discharges and inadequately regulated domestic pollution. A specific emergency drinking water treatment process was quickly developed using a combination of potassium permanganate oxidation and powdered activated carbon adsorption. The emergency treatment process removed the odor from the tap water and solved the crisis successfully in several days. This experience underscores the suggestion that a combination of stresses associated with eutrophication and industrial and domestic wastewater discharges can push an aquatic system to the tipping point with consequences far more severe than would occur if the system were subjected to each stress separately.
•A first distributionally robust approach is proposed for production scheduling.•An explicit expression is provided to calculate the robust CVaR.•Three Cauchy-relaxation algorithms have been proposed ...to solve the problem.•Experimental results show that the proposed algorithms outperform a CPLEX solver.•Robustness of the optimal job sequence is verified via simulation experiments.
This paper presents a distributionally robust (DR) optimization model for the single machine scheduling problem (SMSP) with random job processing time (JPT). To the best of our knowledge, it is the first time a DR optimization approach is applied to production scheduling problems in the literature. Unlike traditional stochastic programming models, which require an exact distribution, the presented DR-SMSP model needs only the mean-covariance information of JPT. Its aim is to find an optimal job sequence by minimizing the worst-case Conditional Value-at-Risk (Robust CVaR) of the job sequence’s total flow time. We give an explicit expression of Robust CVaR, and decompose the DR-SMSP into an assignment problem and an integer second-order cone programming (I-SOCP) problem. To efficiently solve the I-SOCP problem with uncorrelated JPT, we propose three novel Cauchy-relaxation algorithms. The effectiveness and efficiency of these algorithms are evaluated by comparing them to a CPLEX solver, and robustness of the optimal job sequence is verified via comprehensive simulation experiments. In addition, the impact of confidence levels of CVaR on the tradeoff between optimality and robustness is investigated from both theoretical and practical perspectives. Our results convincingly show that the DR-SMSP model is able to enhance the robustness of the optimal job sequence and achieve risk reduction with a small sacrifice on the optimality of the mean value. Through the simulation experiments, we have also been able to identify the strength of each of the proposed algorithms.
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•The imidazolium-based cationic organic polymer (ImCOP) was designed and prepared for efficient removal of TcO4−/ReO4−.•The high acid-base stability was due to the semi-rigid ...structure of ImCOP.•ImCOP with rich adsorption sites exhibited a record uptake capability (1162 mg g−1) and high selectivity for ReO4−.•It showed fast kinetics and high-efficiency removal for ReO4− in simulated wastes.
Rational design of anion-scavenging materials with high selectivity and stability under high acid/base extreme conditions for removing 99TcO4− is still a significant challenge. Herein, we put forward an anion exchange strategy that utilized an imidazolium-based cationic organic polymer (named ImCOP) for efficient capture of perrhenate (ReO4−), a surrogate for TcO4− with nonradioactive. ImCOP was synthesized via the quaternization reaction using tris (4-(1H-imidazol-1-yl) phenyl) amine, a tripodal flexible ligand, and 1,4-bis (bromomethyl) benzene to forming a semi-rigid structure. ImCOP exhibited high chemical stability even under 3 M HNO3 and 3 M NaOH, which was superior to those of most materials. Attributed to the charged imidazolium moieties and tertiary amine groups that produced rich adsorption sites, ImCOP can produce electrostatic interactions with ReO4−, thereby leading to a record uptake capability (1162 mg g−1) of ReO4−. Furthermore, ImCOP exhibited high selectivity for removing ReO4− in the presence of large excess of competitive anions, which was attributed to the hydrophobic surface of ImCOP. These excellent features endowed ImCOP successfully separated ReO4− from simulated Hanford waste with a high adsorption removal of 93.4%. The excellent performance suggested ImCOP would be a promising material for TcO4−/ReO4− removal, which provided a feasible pathway for designing a high-efficiency and durable material for nuclear-related environmental remediation.
Many useful relations between the Gabor transform (GT) and the fractional Fourier transform (FRFT) have been derived. First, we find that, like the Wigner distribution function (WDF), the FRFT is ...also equivalent to the rotation operation of the GT. Then, we show that performing the scaled inverse Fourier transform (IFT) along an oblique line of the GT of f(t) can yield its FRFT. Since the GT is closely related to the FRFT, we can use it for analyzing the characteristics of the FRFT. Compared with the WDF, the GT does not have the cross-term problem. This advantage is important for the applications of filter design, sampling, and multiplexing in the FRFT domain. Moreover, we find that if the GT is combined with the WDF, the resultant operation called the Gabor-Wigner transform (GWT) also has rotation relation with the FRFT. We also derive the general form of the linear distribution that has rotation relation with the FRFT.
We report the first example of vinylene-linked covalent organic framework (Tp-TMT) with enhanced uranium adsorption through combined selective ligand binding, chemical reduction and photocatalytic ...reduction. The dense hydroxyl functional groups on the Tp-TMT framework had good selectivity and excellent chemical reduction performance for U(VI). Meanwhile, the synergistic effect of hydroxyl groups and triazine unit significantly enhanced the photocatalytic reduction activity. Thus Tp-TMT exhibited incredible adsorption kinetics and capacity for uranium.
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•COFs effectively capture uranium through three coordinated mechanisms.•Tp-TMT has excellent visible light conversion efficiency and low band gap.•Tp-TMT enhances uranium adsorption through selective ligand binding and reduction.•Tp-TMT exhibits incredible adsorption kinetics and capacity for uranium.
So far, it remains a challenge to synthesize uranium adsorbents with robust stability, high adsorption capacity, excellent photocatalytic activity and easy regeneration. Herein, we report the first example of vinylene-linked covalent organic framework (Tp-TMT) with enhanced uranium adsorption through combined selective ligand binding, chemical reduction and photocatalytic reduction. The unique structure and excellent photocatalytic activity of Tp-TMT make it very suitable for photo-enhanced uranium adsorption through three synergistic mechanisms, thus exhibiting an outstanding uranium adsorption capacity (2362.4 mg g−1). In the dark, a large number of hydroxyl groups in the Tp-TMT framework serve as selective binding sites for uranium, and reduce part of U(VI) to U(IV), thereby greatly improving the adsorption capacity. Meanwhile, the synergistic effect of the triazine units and hydroxyl groups in the highly conjugated framework greatly decreases the optical band gap of Tp-TMT, and an additional U(VI) photocatalytic reduction process can occur under light irradiation, further increasing the adsorption kinetics and capacity. This work explored the structural and functional design of covalent organic frameworks for the adsorption and reduction of uranium in nuclear industry wastewater.
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