Nanofluidics derived from low‐dimensional nanosheets and protein nanochannels are crucial for advanced catalysis, sensing, and separation. However, polymer nanofluidics is halted by complicated ...preparation and miniaturized sizes. This work reports the bottom‐up synthesis of modular nanofluidics by confined growth of ultrathin metal–organic frameworks (MOFs) in a polymer membrane consisting of zwitterionic dopamine nanoparticles (ZNPs). The confined growth of the MOFs on the ZNPs reduces the chain entanglement between the ZNPs, leading to stiff interfacial channels enhancing the nanofluidic transport of water molecules through the membrane. As such, the water permeability and solute selectivity of MOF@ZNPM are one magnitude improved, leading to a record‐high performance among all polymer nanofiltration membranes. Both the experimental work and the molecular dynamics simulations confirm that the water transport is shifted from high‐friction‐resistance conventional viscous flow to ultrafast nanofluidic flow as a result of rigid and continuous nanochannels in MOF@ZNPM.
A rigid‐scaffold‐reinforced polymeric nanoparticles’ interfacial channel strategy is proposed for fabricating nanofluidic membranes that exhibit water permeance and dye/salt selectivity that are 1–2 orders of magnitude higher than conventional polymeric membranes. The unprecedented separation performance is due to the paradigm shift of water transport from conventional viscous flow to ultrafast nanofluidic flow in the membrane nanofluidics.
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•Novel TFN membranes based on polyelectrolyte nanoparticles (PNPs) were prepared.•TFN-PNP membranes exhibited high water permeability and good selectivity for amino acids.•TFN-PNP ...membranes had good stability and anti-fouling property in nanofiltration process.
We have designed a novel type of thin-film nanocomposite (TFN) membranes with embedded polyelectrolyte nanoparticles (PNPs) and investigated their applicability in the separation of amino acids. PNP particles were mixed with piperazine (PIP) and interfacial polymerized with trimesoyl chloride (TMC), allowing for simultaneous improvement in water permeability, amino acid selectivity, and anti-fouling property. Separation performance could be conveniently tuned by modulating the chemical structure of PNPs and their content in TFN membranes, as well as adjusting the feed pH value. This work would promote the application of polyelectrolyte nanoparticles based TFN membranes in the separation and purification of amino acids.
Nanocomposite membranes have gained growing attention in various application fields, especially in the separation and purification of resource substances. However, the nanomaterials and their ...membranes fabrication strategies usually suffer from complex procedures, high-energy consumption and lack of universality. Inspired by the unique self-polymerization and adhesion characteristic of marine mussels, we proposed a facile and versatile approach to synthesize zwitterionic dopamine nanoparticles via dopamine induced oxidative polymerization method, followed by the interfacial cross-linking on porous supporting layer to fabricate thin-film nanocomposite (TFN) membranes. The influences of nanoparticle composition, particle size and loading content on the membrane structure and performance were studied to optimize the fabrication conditions. The resultant TFN membrane exhibited high water permeance (98.0 L m−2 h−1 MPa−1) and good selectivity for di-/mono-valent salts (SNa2SO4/NaCl = ~4.50, SMgSO4/NaCl = ~4.49). Furthermore, by utilizing the protein, polysaccharide, and humic acid as model foulants, the zwitterionic dopamine nanoparticles based TFN membranes have been demonstrated with excellent fouling resistance and cleaning recovery property in separation applications.
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•Zwitterionic dopamine nanoparticles (ADNPs) were synthesized via dopamine induced oxidative polymerization method.•Thin-film nanocomposite membranes based on ADNPs were prepared by interfacial polymerization.•The membrane had high water permeability and good salt selectivity.•The membrane exhibited good stability and enhanced anti-fouling property.
Over the past decades, the urgent need for high strength conductive hydrogels in diverse applications has motivated an unremitting effort to combine the improved mechanical properties of hydrogels ...with conductive performances. In this work, high strength conductive hydrogels intensified with intermolecular hydrogen bonding are fabricated by in situ mixing poly（2-vinyl-4,6-diamino-1,3,5-triazine-co-polyethylene glycol diacrylates）（PVDT-PEGDA） hydrogels with poly（3,4-ethylenedioxythiophene）-poly（styrenesulfonate）（PEDOT/PSS）. The conductive hydrogels in deionized water exhibit high mechanical performances with compressive strength and tensile strength in the range of 7.58-9.52 MPa and 0.48-1.20 MPa respectively, which are ascribed to the intermolecular hydrogen bonding interactions of diaminotriazinediaminotriazine（DAT-DAT） in the network. Meanwhile, adding PEDOT/PSS can significantly increase both the specific conductivities and equilibrium water contents of the hydrogels. These cytocompatible conductive hydrogels may have a great potential to be used as electrical stimuli responsive soft biomaterials.
Background： Ambient aerosol fine particulate matter （PM2.5） is associated with male reproductive toxicity in experiments and may have adverse effects in the female. However, studies evaluating the ...protective effects and precise mechanisms of aspirin, Vitamin C, Vitamin E, or ozone against toxic effects of PM2.5 are sparse. This study was conducted to investigate the possible protective effects and mechanisms of aspirin, Vitamin C, Vitamin E, or ozone on fertility in female mice treated with PM2.5, Methods： Eighty-four ICR mice were divided into six groups： control group, PM2.5 group, PM2.5 ＋ aspirin group, PM2.5 ＋ Vitamin C group, PM2.5 ＋ Vitamin E group, and PM2.5 ＋ ozone group. PM2.5 was given by intratracheal instillation every 2 days for 3 weeks. Aspirin, Vitamin C, and Vitamin E were given once a day by oral gavage for 3 weeks, and ozone was administered by intraperitoneal injection once a day for 3 weeks. The levels ofanti-Mullerian honnone （AMH）, interleukin-6 （IL-6）, tumor necrosis factor-alpha （TNF-α）, and 8-hydroxy-2＇-deoxyguanosine （8-OHdG） were measured using enzyme-linked immunosorbent assay. Western blotting analysis was used to analyze the expressions ofBcl-2, Bax, and caspase-3 in ovaries. Changes in histological structure were examined by light microscope and electron microscopy was used to detect ultramicrostructure. Results： The results demonstrated that PM2.5 decreased AMH levels （P 〈 0.001）; however, aspirin （P 〈 0.001）, Vitamin C （P 〈 0.001）, Vitamin E （P = 0.001）, and ozone （P = 0.002） alleviated the decrease. Changes of IL-6, TNF-α, 8-OHdG, Bax/Bcl-2, and caspase-3 in PM2.5 group were increased compared to control group （P 〈 0.001）, while in PM2.5 ＋ aspirin, PM2.5 ＋ Vitamin C, PM2.5 ＋ Vitamin E, and PM2.5 ＋ ozone groups, they were statistically decreased compared to PM2.5 group （P 〈 0.001 or P 〈 0.05）. Conclusions： PM2.5 cause the damage of ovaries, and aspirin, Vitamin C, Vitamin E, and ozone antagonizes the damage. The protective mechanism is probably due to its ability to blunt the inflammatory and oxidative stress caused by PM2.5, which subsequently suppressing the expression of apoptotic regulatory protein and reducing the incidence of ovary apoptosis.
Higher-degree polynomial interpolations carried out on uniformly distributed nodes are often plagued by , known as Runge’s phenomenon. This work investigates Runge’s phenomenon and its suppression in ...various versions of the matrix method for black hole quasinormal modes. It is shown that an appropriate choice of boundary conditions gives rise to desirable suppression of oscillations associated with the increasing Lebesgue constant. For the case of discontinuous effective potentials, where the application of the above boundary condition is not feasible, the recently proposed scheme with delimited expansion domain also leads to satisfactory results. The onset of Runge’s phenomenon and its effective suppression are demonstrated by evaluating the relevant waveforms. Furthermore, we argue that both scenarios are either closely related to or practical imitations of the Chebyshev grid. The implications of the present study are also addressed.
In this work, the photosensitive paste was prepared. It was comprised of inorganic particles and a photosensitive organic component. The inorganic panicles included glass, ceramics, and metals. The ...organic component should contain at least the following photosensitive materials： photosensitive monomers, photoreactive copolymer and photopolymerization initiators. The photoreactive copolymer played a role of an adhesive in the photosensitive paste. Meanwhile in the development stage, the carboxyl groups of the copolymer reacted with the alkalescent developer. Following this, the unexposed part must be removed and an excellent pattern can be formed. A series of three-component acrylic copolymers （MAA/St/MMA） were designed, and then synthesized via free radical polymerization. Subsequently glycidyl methacrylate （GMA） was employed to modify the prepared copolymers through ring-opening reactions between the carboxyl groups and the epoxide groups. Eventually the photosensitive copolymers were obtained and used to form the barrier ribs of PDPs. The chemical structure, glass transition temperature, acid value and molecular weight of photosensitive copolymers had different effects on the structure and pattern of PDP barrier ribs. Through analyzing effects of different polymer performance parameters on the patterns of barrier ribs, the optimal photosensitive copolymer was acquired.
Current understanding of ovarian aging Li, Qian; Geng, XiaoDan; Zheng, Wei ...
Science China. Life sciences,
08/2012, Letnik:
55, Številka:
8
Journal Article
Recenzirano
Odprti dostop
The reproductive system of human female exhibits a much faster rate of aging than other body systems. Ovarian aging is thought to be dominated by a gradual decreasing numbers of follicles, coinciding ...with diminished quality of oocytes. Menopause is the final step in the process of ovarian aging. This review focuses on the mechanisms underlying the ovarian aging involving a poor complement of follicles at birth and a high rate of attrition each month, as well as the alternated endocrine factors. We also discuss the possible causative factors that contribute to ovarian aging, e.g., genetic factors, accumulation of irreparable damage of microenvironment, pathological effect and other factors. The appropriate and reliable methods to assess ovarian aging, such as quantification of follicles, endocrine measurement and genetic testing have also been discussed. Increased knowledge of the ovarian aging mechanisms may improve the prevention of premature ovarian failure.
A polarity-sensitive fluorescent probe MNP was rationally designed and synthesized with naphthalimide as the fluorophore and maleimide as the receptor for thiols. MNP is weakly fluorescent due to the ...photoinduced electron-transfer （PET） from the fluorophore to the receptor, and it displays evidently solvatochromic UV-vis and fluorescence spectra： the emission shifted from 495 nm in n-hexane to 545 nm in phosphate buffer solution. Michael addition reaction between thiols and the maleimide in MNP inhibited the PET process, which led to about eight-fold fluorescence enhancement. In addition, MNP showed highly sensitivity to rnercapto-containing proteins and it could detect as low as 20.4 μg/mL of BSA in PBS. MNP has potential in fluorescent imaging of thiols in living cells.
The interaction of Co with ceria thin films and its influence on the sintering behavior of Au were investigated by scanning tunneling microscopy（STM）, synchrotron radiation photoemission ...spectroscopy（SRPES） and X-ray photoelectron spectroscopy（XPS）. The strong interaction between Co and CeO_2（111） leads to oxidation of Co to Co~（2＋） at 300 K, accompanied by partial reduction of ceria surface at low Co coverages. Subsequent Co deposition results in an increasing fraction of metallic Co. Annealing to high temperatures induces Co~（2＋）ions diffuse into the CeO_2 film, while the small metallic Co islands agglomerate into larger ones. The bimetallic Co–Au particles were prepared by deposition of Au on the existing Co particles on ceria surfaces. The sintering behavior of Co–Au bimetallic surfaces is found to be highly determined by the stoichiometry of ceria supports. The addition of Co to the Au/CeO_2 surface suppresses the sintering of Au particles at high temperatures in comparison with that of pure Au particles. However, Au particles are less stable on the Co/CeO_（1.82） layer than on CeO_（1.82） surface.
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