AIM:To investigate the response of the anterior and posterior corneal surface in femtosecond laser-assisted convex stromal lenticule addition keratoplasty(SLAK)combined with cross-linking(CXL)for treating keratoconus ...AIM:To investigate the response of the anterior and posterior corneal surface in femtosecond laser-assisted convex stromal lenticule addition keratoplasty(SLAK)combined with cross-linking(CXL)for treating keratoconus at the first 3mo of follow-up.METHODS:In this prospective observational study,20 eyes of 20 keratoconus patients who underwent SLAK combined with CXL were included.The morphological indices in keratometry and elevation data were recorded from the Sirius at baseline and 1 and 3mo postoperatively.The mean values of maximum keratometry(K_(max)),flat keratometry(K_(1)),and steep keratometry(K_(2))at the central,3-mm,5-mm,and 7-mm areas were measured from the curvature map.The changes in anterior and posterior corneal elevation under the best-fit sphere(BFS)radius at seven points horizontally of the center,3-mm,5-mm,and 7-mm area from the center at both nasal(N)and temporal(T)side were measured from elevation map.RESULTS:For the front corneal curvature,K_(1),and K_(2) at 3-mm,5-mm,and 7-mm of the anterior corneal surface increased significantly 1mo postoperatively(all P<0.05)and remained unchanged until 3mo(P>0.05).For the back corneal curvature,K_(1) and K_(2) along the 3-mm back meridian significantly decreased after month 1(P=0.002,0.077,respectively).Posterior K_(2)-readings along the 5-mm and 7-mm did not change after surgery(P>0.05).Anterior BFS decreased 1mo(P<0.001)postoperatively but remained unchanged until 3mo after SLAK(P>0.05).There was no change in posterior BFS before and after the surgery(P>0.05).Anterior elevation at N5,N3,central,and T5 points and posterior elevation at central and T7 points shifted backward 1mo postoperatively(all P<0.05)and remained stable until 3mo(P>0.05).CONCLUSION:The myopic SLAK combined with CXL is an economical alternative for stabilizing the corneal surface in severe keraoconus.“Pseudoprogression”occurs in the early phase postoperatively,but it is not an indicator of keratoconus progression.展开更多
Polymer binders possess significant potential in alleviating the volume expansion issues of silicon-based anodes,yet remain challenging due to insufficient interfacial interactions with individual components(Si,C,and ...Polymer binders possess significant potential in alleviating the volume expansion issues of silicon-based anodes,yet remain challenging due to insufficient interfacial interactions with individual components(Si,C,and Cu)of the anode.Herein,we report the synthesis of a stable three-dimensional network structure of the PAA-PEA(polyacrylic acid-polyether amines)polymer binder through intermolecular physicochemical dual cross-linking.By incorporating polar functional groups,the binder molecules not only form strong C-O-Si,N-Si,O=C-O-C,and O=C-O-Cu covalent bonds but also enhance non-covalent interactions with Si,C,and Cu,thereby improving adhesion between the binder and each interface of the anode.Furthermore,weak hydrogen bonds,acting as"sacrificial bonds",dissipate energy and disperse accumulated stress,improving the material flexibility.Due to the high mechanical stability of the framework,which combines both rigidity and flexibility and the coupling effect at the three interfaces,the movement and separation of electrode components are effectively restrained,significantly enhancing the cycling stability of silicon-graphite anodes.The PAA-PEA 2000 electrode exhibits a capacity retention of 78% after 500 cycles at a current density of 0.2 A g^(-1).This work provides insights into the mechanism of binders and guides the design of polymer binders for high-performance Si-based electrodes.展开更多
AIM:To compare simultaneous corneal collagen cross-linking(CXL)with intracorneal ring segment(ICRS)implantation versus successive ICRS followed by CXL and detect the impact of the timing of CXL after ICRS implantation...AIM:To compare simultaneous corneal collagen cross-linking(CXL)with intracorneal ring segment(ICRS)implantation versus successive ICRS followed by CXL and detect the impact of the timing of CXL after ICRS implantation in the successive method.METHODS:This is a retrospective study of the records of three groups of patients.Group 1 of 28 patients were operated on with simultaneous ICRS implantation and CXL,group 2 of 32 patients had ICRS implantation followed by CXL after 1mo,and group 3 of 38 patients had ICRS implantation followed by CXL after 3mo.The three groups had follow-up visits after 6,12,and 24mo.RESULTS:The preoperative data,age,and gender differences among 3 groups revealed no significant differences.The postoperative spherical equivalent and best-corrected visual acuity were improved significantly in all groups compared to the baseline,which were more evident in groups 1 and 2.The differences between preoperative and postoperative mean values of mean of K readings(Km)and maximum K reading(Kmax)at 6mo were 4.66 and 4.1 D in group 1,4.43 and 4.64 D in group 2,but 3.2 and 3.4 D in group 3,respectively.The spherical aberrations and the vertical coma showed significant postoperative changes in all groups,and trefoil showed nonsignificant changes.CONCLUSION:Simultaneous and sequential ICRS implantation and CXL at 1mo has similar Km and Kmax better postoperative changes than when both surgeries were done at three-month intervals.展开更多
In this study,a novel cost-effective methodology was developed to enhance the gas barrier properties and permselectivity of unfilled natural rubber(NR)/polybutadiene rubber(BR)composites through the construction of a ...In this study,a novel cost-effective methodology was developed to enhance the gas barrier properties and permselectivity of unfilled natural rubber(NR)/polybutadiene rubber(BR)composites through the construction of a heterogeneous structure using pre-vulcanized powder rubber to replace traditional fillers.The matrix material is composed of a blend of NR and BR,which is widely used in tire manufacturing.By incorporating pre-vulcanized trans-1,4-poly(isoprene-co-butadiene)(TBIR)rubber powder(pVTPR)with different cross-linking densities and contents,significant improvements in the gas barrier properties and CO_(2)permselectivity of the NR/BR/pVTPR composites were observed.The results indicated that compared to NR/BR/TBIR composites prepared through direct blending of NR,BR,and TBIR,the NR/BR/pVTPR composites exhibited markedly superior gas barrier properties.Increasing the cross-linking density of pVTPR resulted in progressive enhancement of the gas barrier properties of the NR/BR/pVTPR composite.For example,the addition of 20 phr pVTPR with a cross-linking density of 346 mol/m^(3)resulted in a 79%improvement in the oxygen barrier property of NR/BR/pVTPR compared to NR/BR,achieving a value of 5.47×10^(-14)cm^(3)·cm·cm^(-2)·s^(-1)·Pa^(-1).Similarly,the nitrogen barrier property improved by 76%compared to NR/BR,reaching 2.4×10^(-14)cm^(3)·cm·cm^(-2)·s^(-1)·Pa^(-1),which is 28%higher than the conventional inner liner material brominated butyl rubber(BIIR,PN2=3.32×10^(-14)cm^(3)·cm·cm^(-2)·s^(-1)·Pa^(-1)).Owing to its low cost,exceptional gas barrier properties,superior adhesion to various tire components,and co-vulcanization capabilities,the NR/BR/pVTPR composite has emerged as a promising alternative to butyl rubber in the inner liner of tires.Furthermore,by fine-tuning the cross-linking density of pVTPR,the high-gas-barrier NR/BR/pVTPR composites also demonstrated remarkable CO_(2)permselectivity,with a CO_(2)/N2 selectivity of 61.4 and a CO_(2)/O_(2)selectivity of 26.12.This innovation provides a novel strategy for CO_(2)capture and separation,with potential applications in future environmental and industrial processes.The multifunctional NR/BR/pVTPR composite,with its superior gas barrier properties and CO_(2)permselectivity,is expected to contribute to the development of safer,greener,and more cost-effective transportation solutions.展开更多
Aging is a persistent topic of interest,with skin aging as its most visible manifestation,characterized by a reduction in intact collagen and elastic fibers in the dermis.Hyaluronic acid,a vital component of the extra...Aging is a persistent topic of interest,with skin aging as its most visible manifestation,characterized by a reduction in intact collagen and elastic fibers in the dermis.Hyaluronic acid,a vital component of the extracellular matrix present in the skin,has become a mainstream method for skin rejuvenation through injections.However,the rapid degradation of pure hyaluronic acid,combined with insufficient maintenance duration and often limited therapeutic effects,presents significant challenges for injectable treatments.Additionally,low patient compliance due to discomfort from needles penetrating the dermal layer further complicates its use.In this review,we summarize and compare existing interventions for skin aging,focusing on strategies to prolong the degradation cycle of hyaluronic acid,including variations in cross-linking modalities and injection techniques.We conclude that the injection of cross-linked modified hyaluronic acid via microneedles represents a promising approach to extend the degradation cycle,offering valuable insights for current therapeutic strategies.展开更多
Selective hydrogenation of furfural to furfuryl alcohol is a great challenge in the hydrogenation field due to thermodynamic preference for hydrogenation of C=C over C=O.Herein,a novel Al_(2)O_(3)/C-u hybrid catalyst,...Selective hydrogenation of furfural to furfuryl alcohol is a great challenge in the hydrogenation field due to thermodynamic preference for hydrogenation of C=C over C=O.Herein,a novel Al_(2)O_(3)/C-u hybrid catalyst,composed of N-modified dendritic carbon networks supporting Al_(2)O_(3)nanoparticles,was successfully prepared via carbonizing the freeze-dried gel from spontaneous cross-linking of alginate,Al3+and urea.The obtained carbon-supported Al_(2)O_(3)hybrid catalyst has a high ratio (31%) of Al species in pentahedral-coordinated state.The introduction of urea enhances the surface N content,the ratio of pyrrolic N,and specific surface area of catalyst,leading to improved adsorption capacity of C=O and the accessibility of active sites.In the furfural hydrogenation reaction with isopropyl alcohol as hydrogen donor,Al_(2)O_(3)/C-u catalyst achieved a 90%conversion of furfural with 98.0% selectivity to furfuryl alcohol,outperforming that of commercial γ-Al_(2)O_(3).Moreover,Al_(2)O_(3)/C-u demonstrates excellent catalytic stability in the recycling tests attributed to the synergistic effect of abundant weak Lewis acid sites and the anchoring effect of the carbon network on Al_(2)O_(3)nanoparticles.This work provides an innovative and facile strategy for fabrication of carbon-supported Al_(2)O_(3)hybrid catalysts with rich AlVspecies,serving as a high selective hydrogenation catalyst through MPV reaction route.展开更多
LiMnxFe1-xPO_(4) is a promising cathode candidate due to its high security and the availability of a high 4.1 V operating voltage and high energy density.However,the poor electrochemical kinetics and structural instab...LiMnxFe1-xPO_(4) is a promising cathode candidate due to its high security and the availability of a high 4.1 V operating voltage and high energy density.However,the poor electrochemical kinetics and structural instability currently hinder its broader application.Herein,inspired by the hydrogen-bonded cross-linking and steric hindrance effect between short-chain polymer molecules(polyethylene glycol-400,PEG-400),the pomegranate-type LiMn_(0.5)Fe_(0.5)PO_(4)-0.5@C(P-LMFP@C)cathode materials with 3D ion/electron dual-conductive network structure were constructed through ball mill-assisted spray-drying method.The intermolecular effects of PEG-400 promote the spheroidization and uniform PEG coating of LMFP precursor,which prevents agglomeration during sintering.The 3D ion/electron dual-conductive network structure in P-LMFP@C accelerates the Li^(+)transport kinetics,improving the rate performance and cycling stability.As a result,the designed P-LMFP@C has remarkable electrochemical behavior,boasting excellent capacity retention(98%after 100 cycles at the 1C rate)and rate capability(91 mAh·g^(-1)at 20C).Such strategy introduces a novel window for designing high-performance olivine cathodes and offers compatibility with a range of energy storage materials for diverse applications.展开更多
Polyimide(PI)is widely used in high-frequency communication technology due to its exceptional comprehensive properties.However,traditional PI has a relatively elevated dielectric constant and dielectric loss.Herein,th...Polyimide(PI)is widely used in high-frequency communication technology due to its exceptional comprehensive properties.However,traditional PI has a relatively elevated dielectric constant and dielectric loss.Herein,the different cross-linked structures were introduced in PI matrix and conducted a detailed discussion on the influence of cross-linking agent content and cross-linking structure type on the overall performance of PI films.In comparison to the dielectric constant of 2.9 of neat PI,PI with an interchain cross-linking structure containing 2 wt%1,3,5-tris(4-aminophenyl)benzene(TAPB)(interchain-PI-2)exhibited the reduced dielectric constant of 2.55 at 1 MHz.The PI films with intrachain crosslinking structure containing 2 wt%TAPB(intrachain-PI-2)exhibited the lowest dielectric constant of 2.35 and the minimum dielectric loss of0.0075 at 1 MHz.It was due to the more entanglement junctions of intrachain-PI resulting in decreased carrier transport.The thermal expansion coefficients of both interchain-PI and intrachain-PI films were effectively reduced.Moreover,in contrast to interchain-PI films,the intrachain-PI films maintained colorlessness and transparency as the cross-linking agent content increased.This work compared the effects of two different cross-linked structures on the performance of PI films and provided a feasible way to obtain low-k PI films with excellent comprehensive performance for 5G applications.展开更多
AIM:To observe the effects of femtosecond laserassisted excimer laser in situ keratomileusis combined with accelerated corneal cross-linking(FS-LASIK Xtra)on corneal densitometry after correcting for high myopia.METHO...AIM:To observe the effects of femtosecond laserassisted excimer laser in situ keratomileusis combined with accelerated corneal cross-linking(FS-LASIK Xtra)on corneal densitometry after correcting for high myopia.METHODS:In this prospectively study,130 patients underwent FS-LASIK or FS-LASIK Xtra for high myopia.Their right eyes were selected for inclusion in the study,of which 65 cases of 65 eyes in the FS-LASIK group,65 patients with 65 eyes in the FS-LASIK Xtra group.Patients were evaluated for corneal densitometry at 1,3,and 6mo postoperatively using Pentacam Scheimpflug imaging.RESULTS:Preoperative differences in corneal densitometry between the FS-LASIK and FS-LASIK Xtra groups in different ranges were not statistically significant(P>0.05).Layer-by-layer analysis revealed statistically significant differences in the anterior(120μm),central,and total layer corneal densitometry between the FS-LASIK and FS-LASIK Xtra groups at 1 and 3mo postoperatively(all P<0.05),the FS-LASIK Xtra group is higher than that of the FS-LASIK group.Analysis of different diameter ranges showed statistically significant differences between the FS-LASIK group and the FS-LASIK Xtra group at 1mo postoperatively in the ranges of 0–2,2–6,and 6–10 mm(both P<0.05);At 3mo postoperatively,the FS-LASIK Xtra group is higher than that of the FS-LASIK group in the ranges of 0–2 and 2–6 mm(P<0.05).At 6mo postoperatively,there were no statistically significant differences in corneal densitometry between the FS-LASIK group and the FS-LASIK Xtra group in different diameter ranges(all P>0.05).CONCLUSION:There is an increase in internal corneal densitometry during the early postoperative period after FS-LASIK Xtra for correction of high myopia.However,the densitometry values decreased to the level of conventional FS-LASIK at 6mo after surgery,with the most significant changes observed in the superficial central zone.展开更多
AIM：To compare the effectiveness and safety between modified cross-linking（MC）and standard cross-linking（SC）in mild or moderate progressive keratoconus.METHODS：Eligible studies were retrieved from four electroni...AIM：To compare the effectiveness and safety between modified cross-linking（MC）and standard cross-linking（SC）in mild or moderate progressive keratoconus.METHODS：Eligible studies were retrieved from four electronic databases,including CENTRAL,Clinical Trials gov,Pup Med and OVID MEDLINE.We set post-surgical maximum K value（Kmax）as the primary outcome.In addition,uncorrected and corrected distant visual acuity（UDVA and UDVA）,spherical equivalent（SE）,endothelial cell density（ECD）,central cornea thickness（CCT）and depth of demarcation line（DDL）were Meta-analyzed as secondary outcomes.Mean differences for these outcomes were pooled through either a random-effect model or fixed-effect model according to data heterogeneity.RESULTS：Twenty-four comparative studies either on accelerated cross-linking（AC）compared with SC or on transepithelial cross-linking（TC）compared with SC were included and pooled for analysis.The results indicated that MC was significantly inferior to SC at delaying Kmax deterioration[AC vs SC 0.49（95%CI：0.04-0.94,I2=75%,P=0.03）;TC vs SC 1.15（95%CI：0.54-1.75,I2=50%,P=0.0002）].SE decreased significantly for SC when compared to AC[0.62（95%CI：0.38-0.86,I2=22%,P〈0.00001）].DDL of SC was more significantly deeper than that of TC[-133.49（95%CI：-145.94 to-121.04,I2=33%,P〈0.00001）].Other outcomes demonstrated comparable results between MC and SC.CONCLUSION：SC is more favorable at halting the progression of keratoconus,but visual acuity improvement showed comparable results between MCs and SC.展开更多
Elastomer blends,among which natural rubber(NR)and butadiene rubber(BR),are involved in many components of the automotive/tire industry.A comprehensive understanding of their mechanical behavior requires,among other f...Elastomer blends,among which natural rubber(NR)and butadiene rubber(BR),are involved in many components of the automotive/tire industry.A comprehensive understanding of their mechanical behavior requires,among other features,a detailed description of the crosslink density in these mixtures.In the case of vulcanized immiscible blends,the distribution of the cross-link density within each of the NR-and BR-rich domains is key information,but difficult to determine using the conventional approaches used for one-component crosslinked elastomers.In this study,the vulcanization within NR/BR blends is investigated using a robust^(1)H double-quantum(DQ)MAS recoupling experiment,BaBa-xy16.Two kinds of cross-linked NR/BR blends were considered with two different microstructures for the BR component.The bulk organization of the resulting blends was first probed by analyzing the^(1)H spin-lattice relaxation behavior.In a second step,BaBa-xy16 was used to investigate,in a selective way,the cross-link heterogeneities within NR/BR blends.In particular,for immiscible NR/BR mixtures,the distribution of the cross-link density between both phases was compared and the observed differences were discussed.展开更多
This study evaluated the clinical outcomes in keratoconus corneas following accelerated transepithelial corneal collagen cross-linking（CXL）（Avedro KXL system,Waltham,MA,USA） over one year of follow-up.The mean de...This study evaluated the clinical outcomes in keratoconus corneas following accelerated transepithelial corneal collagen cross-linking（CXL）（Avedro KXL system,Waltham,MA,USA） over one year of follow-up.The mean depth of the demarcation line measured by optical coherence tomography（OCT） was 205.19 μm.One month after surgery,a non-statistically significant change was noted in sphere（P= 0.18） and in spherical equivalent（P= 0.17）,whereas a significant improvement was observed in corrected distance visual acuity（P=0.04）.A significant change was observed in topographic astigmatism（P= 0.03） and posterior corneal a sphericity（P= 0.04）.Accelerated transepithelial CXL may be a useful technique for the management of progressive keratoconus.展开更多
The aim of the study is to evaluate the safety and effi cacy of trans-epithelial accelerated corneal cross-linking（TE-ACXL） in children with progressive keratoconus.Retrospective,case-series of 23 eyes of 14 childre...The aim of the study is to evaluate the safety and effi cacy of trans-epithelial accelerated corneal cross-linking（TE-ACXL） in children with progressive keratoconus.Retrospective,case-series of 23 eyes of 14 children who underwent TE-ACXL.Evaluations were performed at baseline and 1,3,6,12 and 18 mo postoperatively.Mean follow-up time of 23.82±3.15 mo and mean age was 13.7±1.4 y（range 11 to 16 y）.Mean preoperative uncorrected distance visual acuity changed from 0.92±0.45 log MAR（20/160） to 0.71±0.40 log MAR（20/100）（P=0.001）.Mean keratometry（Km） changed from 53.87± 6.03 to 53.00±5.81（P=0.001）.Pachymetry did not have significant changes at last follow-up（P=0.30）.The mean preoperative sphere was-5.58±2.48 and-4.89±4.66 D（P=0.11） at last follow-up;refractive cylinder from-5.58±2.48 to-5.02±2.23（P=0.046）.In conclusion,tomographic and refractive stability are shown in over 91% of eyes with pediatric progressive keratoconus who underwent TE-ACXL.展开更多
Ethanol perm-selective PDMS/PVDF composite membranes were prepared by curing polydimethylsiloxane (PDMS) with various cross-linking reagents,such as tetraethoxylsilane(TEOS),γ-aminopropyltriethoxylsilane(APTEOS), phe...Ethanol perm-selective PDMS/PVDF composite membranes were prepared by curing polydimethylsiloxane (PDMS) with various cross-linking reagents,such as tetraethoxylsilane(TEOS),γ-aminopropyltriethoxylsilane(APTEOS), phenyltrimethoxylsilane(PTMOS) and octyltrimethoxylsilane(OTMOS) as well.The cross-linking density and surface properties of the PDMS active layer were adjusted by varying cross-linking reagents.The pervaporation performance of PDMS membranes cured with different cross-linking reagents was investig...展开更多
AIM: To evaluate the effect of Collagen cross-linking on the prevention of melting in rabbit corneas after alkali burn. METHODS: Twenty New Zealand white rabbits were randomly divided into model control group and coll...AIM: To evaluate the effect of Collagen cross-linking on the prevention of melting in rabbit corneas after alkali burn. METHODS: Twenty New Zealand white rabbits were randomly divided into model control group and collagen cross-linking treatment group. The second group of rabbits received collagen cross linked treatment. Both groups were applied with antibiotic eye drops to prevent infection. The corneas were evaluated for melting, opacity, pathological and immunohistochemistry, record the changes when 28 days after the animals were killed. RESULTS: In the control group, 6 out of 8 rabbits showed corneal melting after injury (14 +/- 4) days, while two corneal perforated. In collagen cross-linking treatment group, one rabbit showed corneal melting after injury 23 days, without corneal perforation; corneal dissolution rate between the two groups was significantly different (P <0.05). Pathological examination suggested that in the treatment group, mild corneal edema, mild damage to collagen fibers, inflammatory cell infiltration was significantly less than the control group. Immunohistochemistry showed that corneal collagen fibers arranged in neat rows in the control group. CONCLUSION: Collagen cross-linking treatment not only can prevent and delay the corneal melting after alkali burn, but also can reduce the destruction of corneal collagen fibers and infiltration of inflammatory cells in the corneal tissue.展开更多
Membrane fouling is always the biggest problem in the practice of membrane separation technologies,which strongly impacts their applicability,separation efficiency,cost effectiveness,and service lifespan.Herein,a simp...Membrane fouling is always the biggest problem in the practice of membrane separation technologies,which strongly impacts their applicability,separation efficiency,cost effectiveness,and service lifespan.Herein,a simple but effective 3D modification approach was designed for permanently functionalizing polymeric membranes by directly cross-linking polyvinyl alcohol(PVA)under gamma-ray irradiation at room temperature without any additives.After the modification,a PVA layer was constructed on the membrane surface and the pore inner surface of polyvinylidene fluoride(PVDF)membranes.This endowed them with good hydrophilicity,low adsorption of protein model foulants,and easy recoverability properties.In addition,the pore size and distribution were customized by controlling the PVA concentration,which enhanced the rejection ability of the resultant membranes and converted them from microfiltration to ultrafiltration.The crosslinked PVA layer was equipped with the resultant membranes with good resistance to chemical cleaning by acidic,alkaline,and oxidative reagents,which could greatly prolong the membrane service lifetime.Furthermore,this approach was demonstrated as a universal method to modify PVDF membranes with other hydrophilic macromolecular modifiers,including polyethylene glycol,sodium alginate,and polyvinyl pyrrolidone.This modification of the membranes effectively endowed them with good hydrophilicity and antifouling properties,as expected.展开更多
Polyimide(PI)is a promising electronic packaging material,but it remains challenging to obtain an all-organic PI hybrid film with decreased dielectric constant and loss without modifying the monomer.Herein,a series of...Polyimide(PI)is a promising electronic packaging material,but it remains challenging to obtain an all-organic PI hybrid film with decreased dielectric constant and loss without modifying the monomer.Herein,a series of allorganic PI hybrid films were successfully prepared by introducing the covalent organic framework(COF),which could induce the formation of the cross-linking structure in the PI matrix.Due to the synergistic effects of the COF fillers and the cross-linking structure,the PI/COF hybrid film containing 2 wt%COF exhibited the lowest dielectric constant of 2.72 and the lowest dielectric loss(tanδ)of 0.0077 at 1 MHz.It is attributed to the intrinsic low dielectric constant of COF and a large number of mesopores within the PI.Besides,the cross-linking network of PI prevents the molecular chains from stacking and improves the fraction of free volume(FFV).The molecular dynamics simulation results are well consistent with the dielectric properties data.Furthermore,the PI/COF hybrid film with 5 wt%COF showed a significant enhancement in breakdown strength,which increased to 412.8 kV/mm as compared with pure PI.In addition,the PI/COF hybrid film achieve to reduce the dielectric constant and thermal expansion coefficient(CTE).It also exhibited excellent thermal,hydrophobicity,and mechanical performance.The all-organic PI/COF hybrid films have great commercial potential as next-generation electronic packaging materials.展开更多
AIM: To report the 3mo outcomes of collagen crosslinking(CXL) with a hypo-osmolar riboflavin in thin corneas with the thinnest thickness less than 400 μm without epithelium.METHODS: Eight eyes in 6 patients with age ...AIM: To report the 3mo outcomes of collagen crosslinking(CXL) with a hypo-osmolar riboflavin in thin corneas with the thinnest thickness less than 400 μm without epithelium.METHODS: Eight eyes in 6 patients with age 26.2±4.8y were included in the study. All patients underwent CXL using a hypo-osmolar riboflavin solution after its de-epithelization. Best corrected visual acuity, manifest refraction, the thinnest corneal thickness, and endothelial cell density were evaluated before and 3mo after the procedure.RESULTS: The mean thinnest thickness of the cornea was 408.5 ±29.0 μm before treatment and reduced to369.8 ±24.8 μm after the removal of epithelium. With the application of the hypo-osmolar riboflavin solution, the thickness increased to 445.0 ±26.5 μm before CXL and recover to 412.5 ±22.7 μm at 3mo after treatment, P =0.659). Before surgery, the mean K-value of the apex of the keratoconus corneas was 57.6 ±4.0 diopters, and slightly decreased(54.7±4.9 diopters) after surgery(P =0.085). Mean best-corrected visual acuity was 0.55 ±0.23 logarithm of the minimal angle of resolution, and increased to 0.53±0.26 logarithm after surgery(P =0.879).The endothelial cell density was 2706.4 ±201.6 cells/mm2 before treatment, and slightly decreased( 2641. 2 ±218.2 cells/mm2) at last fellow up(P =0.002).CONCLUSION: Corneal collagen cross-linking with a hypo-osmolar riboflavin in thin corneas seems to be a promising treatment. Further study should be done to evaluate the safety and efficiency of CXL in thin corneas for the long-term.展开更多
AIM： To observe the therapeutic effect of corneal collagen cross-linking（CXL） in combination with liposomal amphotericin B in fungal corneal ulcers.METHODS： New Zealand rabbits were induced fungal corneal ulcers b...AIM： To observe the therapeutic effect of corneal collagen cross-linking（CXL） in combination with liposomal amphotericin B in fungal corneal ulcers.METHODS： New Zealand rabbits were induced fungal corneal ulcers by scratching and randomly divided into 3groups, i.e. control, treated with CXL, and combined therapy of CXL with 0.25% liposomal amphotericin B（n =5 each）. The corneal lesions were documented with slit-lamp and confocal microscopy on 3, 7, 14, 21 and 28 d after treatment. The corneas were examined with transmission electron microscopy（TEM） at 4wk.RESULTS： A rabbit corneal ulcer model of Fusarium was successfully established. The corneal epithelium defect areas in the two treatment groups were smaller than that in the control group on 3, 7, 14 and 21d（P 〈0.05）. The corneal epithelium defect areas of the combined group was smaller than that of the CXL group（P 〈0.05） on 7 and 14 d, but there were no statistical differences on 3, 21 and 28 d. The corneal epithelium defects of the two treatment groups have been healed by day 21. The corneal epithelium defects of the control group were healed on 28 d. The diameters of the corneal collagen fiber bundles（42.960 ±7.383 nm in the CXL group and 37.040±4.160 nm in the combined group） were thicker than that of the control group（24.900±1.868 nm）,but there was no difference between the two treatment groups. Some corneal collagen fiber bundles were distorted and with irregular arrangement, a large number of fibroblasts could be seen among them but no inflammatory cells in both treatment groups. CONCLUSION： CXL combined with liposomal amphotericin B have beneficial effects on fungal corneal ulcers. The combined therapy could alleviate corneal inflammattions, accelerate corneal repair, and shorten the course of disease.展开更多
Selective separation of CO_(2)/CH_(4)and C2 H_(2)/CH_(4)are promising for their high-purity industrial demand and scientific research on account of the similar molecular radius and physical properties.In this work,a u...Selective separation of CO_(2)/CH_(4)and C2 H_(2)/CH_(4)are promising for their high-purity industrial demand and scientific research on account of the similar molecular radius and physical properties.In this work,a unique 3 D microporous MOF material[Cu(SiF6)(sdi)2]·solvents(1,sdi=1,1’-sulfonyldiimidazole)was successfully constructed by cross-linking 1 D coordination polymer chains.The dense functional active sites on the inner walls of the channel of la can provide strong binding affinities to CO_(2),C2 H_(2),and thus effectively improve the gas separation performance of CO_(2)/CH_(4)and C2 H_(2)/CH_(4).展开更多
基金Supported by the Social Development Grant of Shaanxi Province(No.2022SF-404)the Science and Technology Program of Xi’an,China(No.23YXYJ0010,No.23YXYJ0037)+1 种基金the Research Project of Xi’an Health Commission(No.2024ms05)the Technology Innovation Supporting Program of Shaanxi(No.2024RS-CXTD-11).
文摘AIM:To investigate the response of the anterior and posterior corneal surface in femtosecond laser-assisted convex stromal lenticule addition keratoplasty(SLAK)combined with cross-linking(CXL)for treating keratoconus at the first 3mo of follow-up.METHODS:In this prospective observational study,20 eyes of 20 keratoconus patients who underwent SLAK combined with CXL were included.The morphological indices in keratometry and elevation data were recorded from the Sirius at baseline and 1 and 3mo postoperatively.The mean values of maximum keratometry(K_(max)),flat keratometry(K_(1)),and steep keratometry(K_(2))at the central,3-mm,5-mm,and 7-mm areas were measured from the curvature map.The changes in anterior and posterior corneal elevation under the best-fit sphere(BFS)radius at seven points horizontally of the center,3-mm,5-mm,and 7-mm area from the center at both nasal(N)and temporal(T)side were measured from elevation map.RESULTS:For the front corneal curvature,K_(1),and K_(2) at 3-mm,5-mm,and 7-mm of the anterior corneal surface increased significantly 1mo postoperatively(all P<0.05)and remained unchanged until 3mo(P>0.05).For the back corneal curvature,K_(1) and K_(2) along the 3-mm back meridian significantly decreased after month 1(P=0.002,0.077,respectively).Posterior K_(2)-readings along the 5-mm and 7-mm did not change after surgery(P>0.05).Anterior BFS decreased 1mo(P<0.001)postoperatively but remained unchanged until 3mo after SLAK(P>0.05).There was no change in posterior BFS before and after the surgery(P>0.05).Anterior elevation at N5,N3,central,and T5 points and posterior elevation at central and T7 points shifted backward 1mo postoperatively(all P<0.05)and remained stable until 3mo(P>0.05).CONCLUSION:The myopic SLAK combined with CXL is an economical alternative for stabilizing the corneal surface in severe keraoconus.“Pseudoprogression”occurs in the early phase postoperatively,but it is not an indicator of keratoconus progression.
基金financial support from the National Natural Science Foundation of China[grant number 21878299]。
文摘Polymer binders possess significant potential in alleviating the volume expansion issues of silicon-based anodes,yet remain challenging due to insufficient interfacial interactions with individual components(Si,C,and Cu)of the anode.Herein,we report the synthesis of a stable three-dimensional network structure of the PAA-PEA(polyacrylic acid-polyether amines)polymer binder through intermolecular physicochemical dual cross-linking.By incorporating polar functional groups,the binder molecules not only form strong C-O-Si,N-Si,O=C-O-C,and O=C-O-Cu covalent bonds but also enhance non-covalent interactions with Si,C,and Cu,thereby improving adhesion between the binder and each interface of the anode.Furthermore,weak hydrogen bonds,acting as"sacrificial bonds",dissipate energy and disperse accumulated stress,improving the material flexibility.Due to the high mechanical stability of the framework,which combines both rigidity and flexibility and the coupling effect at the three interfaces,the movement and separation of electrode components are effectively restrained,significantly enhancing the cycling stability of silicon-graphite anodes.The PAA-PEA 2000 electrode exhibits a capacity retention of 78% after 500 cycles at a current density of 0.2 A g^(-1).This work provides insights into the mechanism of binders and guides the design of polymer binders for high-performance Si-based electrodes.
文摘AIM:To compare simultaneous corneal collagen cross-linking(CXL)with intracorneal ring segment(ICRS)implantation versus successive ICRS followed by CXL and detect the impact of the timing of CXL after ICRS implantation in the successive method.METHODS:This is a retrospective study of the records of three groups of patients.Group 1 of 28 patients were operated on with simultaneous ICRS implantation and CXL,group 2 of 32 patients had ICRS implantation followed by CXL after 1mo,and group 3 of 38 patients had ICRS implantation followed by CXL after 3mo.The three groups had follow-up visits after 6,12,and 24mo.RESULTS:The preoperative data,age,and gender differences among 3 groups revealed no significant differences.The postoperative spherical equivalent and best-corrected visual acuity were improved significantly in all groups compared to the baseline,which were more evident in groups 1 and 2.The differences between preoperative and postoperative mean values of mean of K readings(Km)and maximum K reading(Kmax)at 6mo were 4.66 and 4.1 D in group 1,4.43 and 4.64 D in group 2,but 3.2 and 3.4 D in group 3,respectively.The spherical aberrations and the vertical coma showed significant postoperative changes in all groups,and trefoil showed nonsignificant changes.CONCLUSION:Simultaneous and sequential ICRS implantation and CXL at 1mo has similar Km and Kmax better postoperative changes than when both surgeries were done at three-month intervals.
基金supported by the National Key Research and Development Program of China (No. 2022YFB3704700(2022YFB3704702))the National Natural Science Foundation of China (No. 52473096)+1 种基金Major Scientific and Technological Innovation Project of Shandong Province (No. 2021CXGC010901)Taishan Scholar Program
文摘In this study,a novel cost-effective methodology was developed to enhance the gas barrier properties and permselectivity of unfilled natural rubber(NR)/polybutadiene rubber(BR)composites through the construction of a heterogeneous structure using pre-vulcanized powder rubber to replace traditional fillers.The matrix material is composed of a blend of NR and BR,which is widely used in tire manufacturing.By incorporating pre-vulcanized trans-1,4-poly(isoprene-co-butadiene)(TBIR)rubber powder(pVTPR)with different cross-linking densities and contents,significant improvements in the gas barrier properties and CO_(2)permselectivity of the NR/BR/pVTPR composites were observed.The results indicated that compared to NR/BR/TBIR composites prepared through direct blending of NR,BR,and TBIR,the NR/BR/pVTPR composites exhibited markedly superior gas barrier properties.Increasing the cross-linking density of pVTPR resulted in progressive enhancement of the gas barrier properties of the NR/BR/pVTPR composite.For example,the addition of 20 phr pVTPR with a cross-linking density of 346 mol/m^(3)resulted in a 79%improvement in the oxygen barrier property of NR/BR/pVTPR compared to NR/BR,achieving a value of 5.47×10^(-14)cm^(3)·cm·cm^(-2)·s^(-1)·Pa^(-1).Similarly,the nitrogen barrier property improved by 76%compared to NR/BR,reaching 2.4×10^(-14)cm^(3)·cm·cm^(-2)·s^(-1)·Pa^(-1),which is 28%higher than the conventional inner liner material brominated butyl rubber(BIIR,PN2=3.32×10^(-14)cm^(3)·cm·cm^(-2)·s^(-1)·Pa^(-1)).Owing to its low cost,exceptional gas barrier properties,superior adhesion to various tire components,and co-vulcanization capabilities,the NR/BR/pVTPR composite has emerged as a promising alternative to butyl rubber in the inner liner of tires.Furthermore,by fine-tuning the cross-linking density of pVTPR,the high-gas-barrier NR/BR/pVTPR composites also demonstrated remarkable CO_(2)permselectivity,with a CO_(2)/N2 selectivity of 61.4 and a CO_(2)/O_(2)selectivity of 26.12.This innovation provides a novel strategy for CO_(2)capture and separation,with potential applications in future environmental and industrial processes.The multifunctional NR/BR/pVTPR composite,with its superior gas barrier properties and CO_(2)permselectivity,is expected to contribute to the development of safer,greener,and more cost-effective transportation solutions.
基金financial support from several corporate sponsors.Contributions were made by the National Natural Science Foundation of China(Grant No.32071332)Shenzhen Science and Technology Innovation Project(Grant No.JCYJ20210324095802006)+2 种基金Ningbo Bureau of Science and Technology(Grant No.2023Z187)TransEasy Medical Tech.Co.,Ltd.(Grant No.2021114)Shenzhen University MedTech Innovation Fund(2023YG027).
文摘Aging is a persistent topic of interest,with skin aging as its most visible manifestation,characterized by a reduction in intact collagen and elastic fibers in the dermis.Hyaluronic acid,a vital component of the extracellular matrix present in the skin,has become a mainstream method for skin rejuvenation through injections.However,the rapid degradation of pure hyaluronic acid,combined with insufficient maintenance duration and often limited therapeutic effects,presents significant challenges for injectable treatments.Additionally,low patient compliance due to discomfort from needles penetrating the dermal layer further complicates its use.In this review,we summarize and compare existing interventions for skin aging,focusing on strategies to prolong the degradation cycle of hyaluronic acid,including variations in cross-linking modalities and injection techniques.We conclude that the injection of cross-linked modified hyaluronic acid via microneedles represents a promising approach to extend the degradation cycle,offering valuable insights for current therapeutic strategies.
基金China Postdoctoral Science Foundation (2023M733451)Dalian Innovation Team in Key Areas(2020RT06)Engineering Research Center for Key Aromatic Compounds and LiaoNing Key Laboratory,Liaoning Provincial Natural Science Foundation (Doctoral Research Start-up Fund 2024-BSBA-37)。
文摘Selective hydrogenation of furfural to furfuryl alcohol is a great challenge in the hydrogenation field due to thermodynamic preference for hydrogenation of C=C over C=O.Herein,a novel Al_(2)O_(3)/C-u hybrid catalyst,composed of N-modified dendritic carbon networks supporting Al_(2)O_(3)nanoparticles,was successfully prepared via carbonizing the freeze-dried gel from spontaneous cross-linking of alginate,Al3+and urea.The obtained carbon-supported Al_(2)O_(3)hybrid catalyst has a high ratio (31%) of Al species in pentahedral-coordinated state.The introduction of urea enhances the surface N content,the ratio of pyrrolic N,and specific surface area of catalyst,leading to improved adsorption capacity of C=O and the accessibility of active sites.In the furfural hydrogenation reaction with isopropyl alcohol as hydrogen donor,Al_(2)O_(3)/C-u catalyst achieved a 90%conversion of furfural with 98.0% selectivity to furfuryl alcohol,outperforming that of commercial γ-Al_(2)O_(3).Moreover,Al_(2)O_(3)/C-u demonstrates excellent catalytic stability in the recycling tests attributed to the synergistic effect of abundant weak Lewis acid sites and the anchoring effect of the carbon network on Al_(2)O_(3)nanoparticles.This work provides an innovative and facile strategy for fabrication of carbon-supported Al_(2)O_(3)hybrid catalysts with rich AlVspecies,serving as a high selective hydrogenation catalyst through MPV reaction route.
基金supported by the Key Technologies R&D Program of Xiamen(No.3502Z20231057)Industry Leading Key Projects of Fujian Province(No.2022H0057)+2 种基金the National Natural Science Foundation of China(No.21975212)High-Level Talent Start-Up Foundation of Xiamen Institute of Technology for financial support(No.YKJ23017R)Graduate Science and Technology Innovation Program of Xiamen University of Technology(No.YKJCX2023194).
文摘LiMnxFe1-xPO_(4) is a promising cathode candidate due to its high security and the availability of a high 4.1 V operating voltage and high energy density.However,the poor electrochemical kinetics and structural instability currently hinder its broader application.Herein,inspired by the hydrogen-bonded cross-linking and steric hindrance effect between short-chain polymer molecules(polyethylene glycol-400,PEG-400),the pomegranate-type LiMn_(0.5)Fe_(0.5)PO_(4)-0.5@C(P-LMFP@C)cathode materials with 3D ion/electron dual-conductive network structure were constructed through ball mill-assisted spray-drying method.The intermolecular effects of PEG-400 promote the spheroidization and uniform PEG coating of LMFP precursor,which prevents agglomeration during sintering.The 3D ion/electron dual-conductive network structure in P-LMFP@C accelerates the Li^(+)transport kinetics,improving the rate performance and cycling stability.As a result,the designed P-LMFP@C has remarkable electrochemical behavior,boasting excellent capacity retention(98%after 100 cycles at the 1C rate)and rate capability(91 mAh·g^(-1)at 20C).Such strategy introduces a novel window for designing high-performance olivine cathodes and offers compatibility with a range of energy storage materials for diverse applications.
基金financially supported by the National Natural Science Foundation of China(No.52103029)。
文摘Polyimide(PI)is widely used in high-frequency communication technology due to its exceptional comprehensive properties.However,traditional PI has a relatively elevated dielectric constant and dielectric loss.Herein,the different cross-linked structures were introduced in PI matrix and conducted a detailed discussion on the influence of cross-linking agent content and cross-linking structure type on the overall performance of PI films.In comparison to the dielectric constant of 2.9 of neat PI,PI with an interchain cross-linking structure containing 2 wt%1,3,5-tris(4-aminophenyl)benzene(TAPB)(interchain-PI-2)exhibited the reduced dielectric constant of 2.55 at 1 MHz.The PI films with intrachain crosslinking structure containing 2 wt%TAPB(intrachain-PI-2)exhibited the lowest dielectric constant of 2.35 and the minimum dielectric loss of0.0075 at 1 MHz.It was due to the more entanglement junctions of intrachain-PI resulting in decreased carrier transport.The thermal expansion coefficients of both interchain-PI and intrachain-PI films were effectively reduced.Moreover,in contrast to interchain-PI films,the intrachain-PI films maintained colorlessness and transparency as the cross-linking agent content increased.This work compared the effects of two different cross-linked structures on the performance of PI films and provided a feasible way to obtain low-k PI films with excellent comprehensive performance for 5G applications.
基金Supported by Shandong Province Medical Staff Science and Technology Innovation Program Project(No.SDYWZGKCJH2022021).
文摘AIM:To observe the effects of femtosecond laserassisted excimer laser in situ keratomileusis combined with accelerated corneal cross-linking(FS-LASIK Xtra)on corneal densitometry after correcting for high myopia.METHODS:In this prospectively study,130 patients underwent FS-LASIK or FS-LASIK Xtra for high myopia.Their right eyes were selected for inclusion in the study,of which 65 cases of 65 eyes in the FS-LASIK group,65 patients with 65 eyes in the FS-LASIK Xtra group.Patients were evaluated for corneal densitometry at 1,3,and 6mo postoperatively using Pentacam Scheimpflug imaging.RESULTS:Preoperative differences in corneal densitometry between the FS-LASIK and FS-LASIK Xtra groups in different ranges were not statistically significant(P>0.05).Layer-by-layer analysis revealed statistically significant differences in the anterior(120μm),central,and total layer corneal densitometry between the FS-LASIK and FS-LASIK Xtra groups at 1 and 3mo postoperatively(all P<0.05),the FS-LASIK Xtra group is higher than that of the FS-LASIK group.Analysis of different diameter ranges showed statistically significant differences between the FS-LASIK group and the FS-LASIK Xtra group at 1mo postoperatively in the ranges of 0–2,2–6,and 6–10 mm(both P<0.05);At 3mo postoperatively,the FS-LASIK Xtra group is higher than that of the FS-LASIK group in the ranges of 0–2 and 2–6 mm(P<0.05).At 6mo postoperatively,there were no statistically significant differences in corneal densitometry between the FS-LASIK group and the FS-LASIK Xtra group in different diameter ranges(all P>0.05).CONCLUSION:There is an increase in internal corneal densitometry during the early postoperative period after FS-LASIK Xtra for correction of high myopia.However,the densitometry values decreased to the level of conventional FS-LASIK at 6mo after surgery,with the most significant changes observed in the superficial central zone.
文摘AIM：To compare the effectiveness and safety between modified cross-linking（MC）and standard cross-linking（SC）in mild or moderate progressive keratoconus.METHODS：Eligible studies were retrieved from four electronic databases,including CENTRAL,Clinical Trials gov,Pup Med and OVID MEDLINE.We set post-surgical maximum K value（Kmax）as the primary outcome.In addition,uncorrected and corrected distant visual acuity（UDVA and UDVA）,spherical equivalent（SE）,endothelial cell density（ECD）,central cornea thickness（CCT）and depth of demarcation line（DDL）were Meta-analyzed as secondary outcomes.Mean differences for these outcomes were pooled through either a random-effect model or fixed-effect model according to data heterogeneity.RESULTS：Twenty-four comparative studies either on accelerated cross-linking（AC）compared with SC or on transepithelial cross-linking（TC）compared with SC were included and pooled for analysis.The results indicated that MC was significantly inferior to SC at delaying Kmax deterioration[AC vs SC 0.49（95%CI：0.04-0.94,I2=75%,P=0.03）;TC vs SC 1.15（95%CI：0.54-1.75,I2=50%,P=0.0002）].SE decreased significantly for SC when compared to AC[0.62（95%CI：0.38-0.86,I2=22%,P〈0.00001）].DDL of SC was more significantly deeper than that of TC[-133.49（95%CI：-145.94 to-121.04,I2=33%,P〈0.00001）].Other outcomes demonstrated comparable results between MC and SC.CONCLUSION：SC is more favorable at halting the progression of keratoconus,but visual acuity improvement showed comparable results between MCs and SC.
基金financial support from the French National Research Agency(ANR)[grant number ANR-22-CE06-0031]。
文摘Elastomer blends,among which natural rubber(NR)and butadiene rubber(BR),are involved in many components of the automotive/tire industry.A comprehensive understanding of their mechanical behavior requires,among other features,a detailed description of the crosslink density in these mixtures.In the case of vulcanized immiscible blends,the distribution of the cross-link density within each of the NR-and BR-rich domains is key information,but difficult to determine using the conventional approaches used for one-component crosslinked elastomers.In this study,the vulcanization within NR/BR blends is investigated using a robust^(1)H double-quantum(DQ)MAS recoupling experiment,BaBa-xy16.Two kinds of cross-linked NR/BR blends were considered with two different microstructures for the BR component.The bulk organization of the resulting blends was first probed by analyzing the^(1)H spin-lattice relaxation behavior.In a second step,BaBa-xy16 was used to investigate,in a selective way,the cross-link heterogeneities within NR/BR blends.In particular,for immiscible NR/BR mixtures,the distribution of the cross-link density between both phases was compared and the observed differences were discussed.
文摘This study evaluated the clinical outcomes in keratoconus corneas following accelerated transepithelial corneal collagen cross-linking（CXL）（Avedro KXL system,Waltham,MA,USA） over one year of follow-up.The mean depth of the demarcation line measured by optical coherence tomography（OCT） was 205.19 μm.One month after surgery,a non-statistically significant change was noted in sphere（P= 0.18） and in spherical equivalent（P= 0.17）,whereas a significant improvement was observed in corrected distance visual acuity（P=0.04）.A significant change was observed in topographic astigmatism（P= 0.03） and posterior corneal a sphericity（P= 0.04）.Accelerated transepithelial CXL may be a useful technique for the management of progressive keratoconus.
文摘The aim of the study is to evaluate the safety and effi cacy of trans-epithelial accelerated corneal cross-linking（TE-ACXL） in children with progressive keratoconus.Retrospective,case-series of 23 eyes of 14 children who underwent TE-ACXL.Evaluations were performed at baseline and 1,3,6,12 and 18 mo postoperatively.Mean follow-up time of 23.82±3.15 mo and mean age was 13.7±1.4 y（range 11 to 16 y）.Mean preoperative uncorrected distance visual acuity changed from 0.92±0.45 log MAR（20/160） to 0.71±0.40 log MAR（20/100）（P=0.001）.Mean keratometry（Km） changed from 53.87± 6.03 to 53.00±5.81（P=0.001）.Pachymetry did not have significant changes at last follow-up（P=0.30）.The mean preoperative sphere was-5.58±2.48 and-4.89±4.66 D（P=0.11） at last follow-up;refractive cylinder from-5.58±2.48 to-5.02±2.23（P=0.046）.In conclusion,tomographic and refractive stability are shown in over 91% of eyes with pediatric progressive keratoconus who underwent TE-ACXL.
基金supported by the Major State Basic Research Program of China(No.2009CB623404)National NaturalScience Foundation of China(Nos.20736003,20676067)+2 种基金National High Technology Research and Development Programof China(No.2007AA06Z317)Foundation of Ministry of Education of China(No.20070003130)Foundation of theState Key Laboratory of Chemical Engineering(SKL-ChE-08A01).
文摘Ethanol perm-selective PDMS/PVDF composite membranes were prepared by curing polydimethylsiloxane (PDMS) with various cross-linking reagents,such as tetraethoxylsilane(TEOS),γ-aminopropyltriethoxylsilane(APTEOS), phenyltrimethoxylsilane(PTMOS) and octyltrimethoxylsilane(OTMOS) as well.The cross-linking density and surface properties of the PDMS active layer were adjusted by varying cross-linking reagents.The pervaporation performance of PDMS membranes cured with different cross-linking reagents was investig...
文摘AIM: To evaluate the effect of Collagen cross-linking on the prevention of melting in rabbit corneas after alkali burn. METHODS: Twenty New Zealand white rabbits were randomly divided into model control group and collagen cross-linking treatment group. The second group of rabbits received collagen cross linked treatment. Both groups were applied with antibiotic eye drops to prevent infection. The corneas were evaluated for melting, opacity, pathological and immunohistochemistry, record the changes when 28 days after the animals were killed. RESULTS: In the control group, 6 out of 8 rabbits showed corneal melting after injury (14 +/- 4) days, while two corneal perforated. In collagen cross-linking treatment group, one rabbit showed corneal melting after injury 23 days, without corneal perforation; corneal dissolution rate between the two groups was significantly different (P <0.05). Pathological examination suggested that in the treatment group, mild corneal edema, mild damage to collagen fibers, inflammatory cell infiltration was significantly less than the control group. Immunohistochemistry showed that corneal collagen fibers arranged in neat rows in the control group. CONCLUSION: Collagen cross-linking treatment not only can prevent and delay the corneal melting after alkali burn, but also can reduce the destruction of corneal collagen fibers and infiltration of inflammatory cells in the corneal tissue.
基金This work was supported by the National Natural Science Foundation of China(Nos.11875313,12075153,and 11575277).
文摘Membrane fouling is always the biggest problem in the practice of membrane separation technologies,which strongly impacts their applicability,separation efficiency,cost effectiveness,and service lifespan.Herein,a simple but effective 3D modification approach was designed for permanently functionalizing polymeric membranes by directly cross-linking polyvinyl alcohol(PVA)under gamma-ray irradiation at room temperature without any additives.After the modification,a PVA layer was constructed on the membrane surface and the pore inner surface of polyvinylidene fluoride(PVDF)membranes.This endowed them with good hydrophilicity,low adsorption of protein model foulants,and easy recoverability properties.In addition,the pore size and distribution were customized by controlling the PVA concentration,which enhanced the rejection ability of the resultant membranes and converted them from microfiltration to ultrafiltration.The crosslinked PVA layer was equipped with the resultant membranes with good resistance to chemical cleaning by acidic,alkaline,and oxidative reagents,which could greatly prolong the membrane service lifetime.Furthermore,this approach was demonstrated as a universal method to modify PVDF membranes with other hydrophilic macromolecular modifiers,including polyethylene glycol,sodium alginate,and polyvinyl pyrrolidone.This modification of the membranes effectively endowed them with good hydrophilicity and antifouling properties,as expected.
基金supported by National Natural Science Foundation of China(52103029 and 51903075).
文摘Polyimide(PI)is a promising electronic packaging material,but it remains challenging to obtain an all-organic PI hybrid film with decreased dielectric constant and loss without modifying the monomer.Herein,a series of allorganic PI hybrid films were successfully prepared by introducing the covalent organic framework(COF),which could induce the formation of the cross-linking structure in the PI matrix.Due to the synergistic effects of the COF fillers and the cross-linking structure,the PI/COF hybrid film containing 2 wt%COF exhibited the lowest dielectric constant of 2.72 and the lowest dielectric loss(tanδ)of 0.0077 at 1 MHz.It is attributed to the intrinsic low dielectric constant of COF and a large number of mesopores within the PI.Besides,the cross-linking network of PI prevents the molecular chains from stacking and improves the fraction of free volume(FFV).The molecular dynamics simulation results are well consistent with the dielectric properties data.Furthermore,the PI/COF hybrid film with 5 wt%COF showed a significant enhancement in breakdown strength,which increased to 412.8 kV/mm as compared with pure PI.In addition,the PI/COF hybrid film achieve to reduce the dielectric constant and thermal expansion coefficient(CTE).It also exhibited excellent thermal,hydrophobicity,and mechanical performance.The all-organic PI/COF hybrid films have great commercial potential as next-generation electronic packaging materials.
文摘AIM: To report the 3mo outcomes of collagen crosslinking(CXL) with a hypo-osmolar riboflavin in thin corneas with the thinnest thickness less than 400 μm without epithelium.METHODS: Eight eyes in 6 patients with age 26.2±4.8y were included in the study. All patients underwent CXL using a hypo-osmolar riboflavin solution after its de-epithelization. Best corrected visual acuity, manifest refraction, the thinnest corneal thickness, and endothelial cell density were evaluated before and 3mo after the procedure.RESULTS: The mean thinnest thickness of the cornea was 408.5 ±29.0 μm before treatment and reduced to369.8 ±24.8 μm after the removal of epithelium. With the application of the hypo-osmolar riboflavin solution, the thickness increased to 445.0 ±26.5 μm before CXL and recover to 412.5 ±22.7 μm at 3mo after treatment, P =0.659). Before surgery, the mean K-value of the apex of the keratoconus corneas was 57.6 ±4.0 diopters, and slightly decreased(54.7±4.9 diopters) after surgery(P =0.085). Mean best-corrected visual acuity was 0.55 ±0.23 logarithm of the minimal angle of resolution, and increased to 0.53±0.26 logarithm after surgery(P =0.879).The endothelial cell density was 2706.4 ±201.6 cells/mm2 before treatment, and slightly decreased( 2641. 2 ±218.2 cells/mm2) at last fellow up(P =0.002).CONCLUSION: Corneal collagen cross-linking with a hypo-osmolar riboflavin in thin corneas seems to be a promising treatment. Further study should be done to evaluate the safety and efficiency of CXL in thin corneas for the long-term.
基金Supported by Nature Science Fundamental Research Planned Projects of Shaanxi Province(No.2011JE005No.2012JM4023)Science and Technology Planned Projects of Xi'an[No.SF1207(1)]
文摘AIM： To observe the therapeutic effect of corneal collagen cross-linking（CXL） in combination with liposomal amphotericin B in fungal corneal ulcers.METHODS： New Zealand rabbits were induced fungal corneal ulcers by scratching and randomly divided into 3groups, i.e. control, treated with CXL, and combined therapy of CXL with 0.25% liposomal amphotericin B（n =5 each）. The corneal lesions were documented with slit-lamp and confocal microscopy on 3, 7, 14, 21 and 28 d after treatment. The corneas were examined with transmission electron microscopy（TEM） at 4wk.RESULTS： A rabbit corneal ulcer model of Fusarium was successfully established. The corneal epithelium defect areas in the two treatment groups were smaller than that in the control group on 3, 7, 14 and 21d（P 〈0.05）. The corneal epithelium defect areas of the combined group was smaller than that of the CXL group（P 〈0.05） on 7 and 14 d, but there were no statistical differences on 3, 21 and 28 d. The corneal epithelium defects of the two treatment groups have been healed by day 21. The corneal epithelium defects of the control group were healed on 28 d. The diameters of the corneal collagen fiber bundles（42.960 ±7.383 nm in the CXL group and 37.040±4.160 nm in the combined group） were thicker than that of the control group（24.900±1.868 nm）,but there was no difference between the two treatment groups. Some corneal collagen fiber bundles were distorted and with irregular arrangement, a large number of fibroblasts could be seen among them but no inflammatory cells in both treatment groups. CONCLUSION： CXL combined with liposomal amphotericin B have beneficial effects on fungal corneal ulcers. The combined therapy could alleviate corneal inflammattions, accelerate corneal repair, and shorten the course of disease.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.91856124 and 21531005)Nature Science Fund of Tianjin,China(No.19JCZDJC37200)。
文摘Selective separation of CO_(2)/CH_(4)and C2 H_(2)/CH_(4)are promising for their high-purity industrial demand and scientific research on account of the similar molecular radius and physical properties.In this work,a unique 3 D microporous MOF material[Cu(SiF6)(sdi)2]·solvents(1,sdi=1,1’-sulfonyldiimidazole)was successfully constructed by cross-linking 1 D coordination polymer chains.The dense functional active sites on the inner walls of the channel of la can provide strong binding affinities to CO_(2),C2 H_(2),and thus effectively improve the gas separation performance of CO_(2)/CH_(4)and C2 H_(2)/CH_(4).
