- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Dose-dependent enhancement of bioactivity by surface ZnO nanostructures on acid-etched pure titanium
摘要： Zinc (Zn) is found to be essential in biologic osseous functions, and deficiency of Zn may cause delayed skeletal growth and osteoporosis. Additionally, Zn-based coatings are reported to be effective to promote the bioactivity of implants. In this study, we employed the hydrothermal treatment to incorporate Zn into the surface of acid-etched pure Ti. The process was conducted in ammonia solution with an increased Zn precursor concentration (0.0002 M, 0.002 M and 0.02 M, respectively). XPS analysis demonstrated that the nanostructures were composed of ZnO. Proliferation and alkaline phosphatase (ALP) activity of osteoblast-like SaOS-2 cells were enhanced dose-dependently, compared to those on the acid-etched pure Ti without ZnO nanostructures. This study addresses a favourable surface modification method to improve the bioactivity of implants.
关键词： nanostructure,titanium,bone regeneration,hydrothermal treatment,ZnO
更新于2025-09-23 15:23:52
-
Formation and Clearance of All- <i>Trans</i> -Retinol in Rods Investigated in the Living Primate Eye With Two-Photon Ophthalmoscopy
摘要： PURPOSE. Two-photon excited fluorescence (TPEF) imaging has potential as a functional tool for tracking visual pigment regeneration in the living eye. Previous studies have shown that all-trans-retinol is likely the chief source of time-varying TPEF from photoreceptors. Endogenous TPEF from retinol could provide the specificity desired for tracking the visual cycle. However, in vivo characterization of native retinol kinetics is complicated by visual stimulation from the imaging beam. We have developed an imaging scheme for overcoming these challenges and monitored the formation and clearance of retinol. METHODS. Three macaques were imaged by using an in vivo two-photon ophthalmoscope. Endogenous TPEF was excited at 730 nm and recorded through the eye’s pupil for more than 90 seconds. Two-photon excited fluorescence increased with onset of light and plateaued within 40 seconds, at which point, brief incremental stimuli were delivered at 561 nm. The responses of rods to stimulation were analyzed by using first-order kinetics. RESULTS. Two-photon excited fluorescence resulting from retinol production corresponded to the fraction of rhodopsin bleached. The photosensitivity of rhodopsin was estimated to be 6.88 ± 5.50 log scotopic troland. The rate of retinol clearance depended on intensity of incremental stimulation. Clearance was faster for stronger stimuli and time constants ranged from 50 to 300 seconds. CONCLUSIONS. This study demonstrates a method for rapidly measuring the rate of clearance of retinol in vivo. Moreover, TPEF generated due to retinol can be used as a measure of rhodopsin depletion, similar to densitometry. This enhances the utility of two-photon ophthalmoscopy as a technique for evaluating the visual cycle in the living eye.
关键词： photoreceptors,visual cycle,ophthalmic imaging,pigment regeneration
更新于2025-09-23 15:22:29
-
Shedding light on biocatalysis: photoelectrochemical platforms for solar-driven biotransformation
摘要： Redox biocatalysis has come to the forefront because of its excellent catalytic efficiency, stereoselectivity, and environmental benignity. The green and sustainable biotransformation can be driven by photoelectrochemical (PEC) platforms where redox biocatalysis is coupled with photoelectrocatalysis. The main challenge is how to transfer photoexcited electrons to (or from) the enzyme redox centers for effective biotransformation using solar energy. This review commences with a conceptual discussion of biocatalytic PEC platforms and highlights recent advances in PEC-based biotransformation through cofactor regeneration or direct transfer of charge carriers to (or from) oxidoreductases on enzyme-conjugated electrodes. Finally, we address future perspectives and potential next steps in the vibrant field of biocatalytic photosynthesis.
关键词： photoelectrochemical,cofactor regeneration,biotransformation,redox enzymes,solar-driven,biocatalysis,direct electron transfer
更新于2025-09-23 15:22:29
-
Photocatalytic Degradation of Reactive Brilliant Red X-3B Based on Microwave Electrodeless Lamp and Long Lifetime Immobilized TiO<sub/>2</sub>
摘要： A novel photocatalytic system (MEL/TiO2/QS) based on microwave electrodeless lamp (MEL) and TiO2 films supported on quartz sheets (TiO2/QS) was established for high photocatalytic efficiency and long catalyst life. The results showed that the degradation efficiency for reactive brilliant red X-3B in MEL/TiO2/QS was equally as that in a suspended TiO2 system. Furthermore, under the microwave irradiation, the TiO2/QS had high catalytic activity after successively used 10 times without additional separation and regeneration. The pseudo-first-order kinetics was employed to describe decomposition of the dye and reaction rates at different initial dye concentrations, followed by the Langmuir–Hinshelwood kinetic model. The mineralization process and final products were also analyzed by total organic carbon (TOC) and ion chromatography (IC). The research might be useful in the commercial scale application of low cost and high efficiency photocatalytic process.
关键词： reactive brilliant red X-3B,Catalyst regeneration,microwave electrodeless lamp,TiO2 films
更新于2025-09-23 15:22:29
-
Different Effect of Sox11 in Retinal Ganglion Cells Survival and Axon Regeneration
摘要： Purpose: The present study examines the role of Sox11 in the initial response of retinal ganglion cells (RGCs) to axon damage and in optic nerve regeneration in mouse. Methods: Markers of retinal injury were identified using the normal retina database and optic nerve crush (ONC) database on GeneNetwork2 (www.genenetwork.org). One gene, Sox11, was highly upregulated following ONC. We examined the role of this transcription factor, Sox11, following ONC and optic nerve regeneration in mice. In situ hybridization was performed using the Affymetrix 2-plex Quantigene View RNA In Situ Hybridization Tissue Assay System. Sox11 was partially knocked out by intravitreal injection of AAV2-CMV-Cre-GFP in Sox11f/f mice. Optic nerve regeneration model used Pten knockdown. Mice were perfused and the retinas and optic nerves were dissected and examined for RGC survival and axon growth. Results: Sox11 was dramatically upregulated in the retina following ONC injury. The level of Sox11 message increased by approximately eightfold 2 days after ONC. In situ hybridization demonstrated low-level Sox11 message in RGCs and cells in the inner nuclear layer in the normal retina as well as a profound increase in Sox11 message within the ganglion cells following ONC. In Sox11f/f retinas, partially knocking out Sox11 significantly increased RGC survival after ONC as compared to the AAV2-CMV-GFP control group; however, it had little effect on the ability of axon regeneration. Combinatorial downregulation of both Sox11 and Pten resulted in a significant increase in RGC survival as compared to Pten knockdown only. When Pten was knocked down there was a remarkable increase in the number and the length of regenerating axons. Partially knocking out Sox11 in combination with Pten deletion resulted in a fewer regenerating axons. Conclusion: Taken together, these data demonstrate that Sox11 is involved in the initial response of the retina to injury, playing a role in the early attempts of axon regeneration and neuronal survival. Downregulation of Sox11 aids in RGC survival following injury of optic nerve axons, while a partial knockout of Sox11 negates the axon regeneration stimulated by Pten knockdown.
关键词： optic nerve crush,AAV2,retinal ganglion cells,axon regeneration,Sox11
更新于2025-09-23 15:22:29
-
Enhancement of osteoblast activity on nanostructured NiTi/hydroxyapatite coatings on additive manufactured NiTi metal implants by nanosecond pulsed laser sintering
摘要： Background: The osteoinductive behaviors of nitinol (NiTi)-based metal implants for bone regeneration are largely dependent on their surface composition and topology. Continuous-mode laser sintering often results in complete melting of the materials and aggregation of particles, which lack control of heat transfer, as well as microstructural changes during sintering of the nanocomposite materials. Methods: In the current study, in situ direct laser deposition was used to additively manufacture three-dimensional NiTi structures from Ni and Ti powders. The mechanical property of NiTi has been shown to be similar to bone. Nanosecond pulsed laser sintering process was then utilized to generate a nanoporous composite surface with NiTi alloy and hydroxyapatite (HA) by ultrafast laser heating and cooling of Ni, Ti, and HA nanoparticles mixtures precoated on the 3D NiTi substrates; HA was added in order to improve the biocompatibility of the alloy. We then studied the underlying mechanism in the formation of NiTi/HA nanocomposite, and the synergistic effect of the sintered HA component and the nanoporous topology of the composite coating. In addition, we examined the activity of bone-forming osteoblasts on the NiTi/HA surfaces. For this, osteoblast cell morphology and various biomarkers were examined to evaluate cellular activity and function. Results: We found that the nanoscale porosity delivered by nanosecond pulsed laser sintering and the HA component positively contributed to osteoblast differentiation, as indicated by an increase in the expression of collagen and alkaline phosphatase, both of which are necessary for osteoblast mineralization. In addition, we observed topological complexities which appeared to boost the activity of osteoblasts, including an increase in actin cytoskeletal structures and adhesion structures. Conclusion: These findings demonstrate that the pulsed laser sintering method is an effective tool to generate biocompatible coatings in complex alloy-composite material systems with desired composition and topology. Our findings also provide a better understanding of the osteoinductive behavior of the sintered nanocomposite coatings for use in orthopedic and bone regeneration applications.
关键词： metal implants,pulsed laser coating,biocompatibility,differentiation,bone regeneration,alkaline phosphatase,osteoinductive behavior
更新于2025-09-23 15:22:29
-
Return of function after CNS axon regeneration: Lessons from injury-responsive intrinsically photosensitive and alpha retinal ganglion cells
摘要： This review addresses issues relating to the survival and axon regeneration of both intrinsically photosensitive retinal ganglion cells (ipRGC) and αRGC, and possible ensuing patterns of functional recovery after optic nerve crush, all of which are broadly relevant to recovery from injury in the central nervous system (CNS) as whole. Although much needs to be clarified about the connectivity, function and patterns of myelination of regenerated CNS axons, the results of recent research on activity-induced αRGC axon regeneration associated with functional restitution have highlighted key focal obstacles to recovery including neurotrophic support, axon misguidance, target recognition failure and dysmyelination. Pan RGC survival/axon regeneration requires receptor binding and downstream signalling by a cocktail of growth factors, more generally defined in the CNS by the individual trophic requirements of neuronal subsets within a given disconnected centre. Resolution of the problem of failed axon guidance and target recognition is complicated by a confounding paradox that axon growth inhibitory ligand disinhibition required for axon regeneration may mask axon guidance cues that are essential for accurate re-innervation. The study of the temporal parameters of remyelination of regenerated αRGC axons may become feasible if they establish permanent homologous connections, allowing time for new myelin sheaths to fully form. Unless near complete re-innervation of denervated targets is re-instated in the CNS, debilitating dysfunctional neurological sequelae may ensue from the resulting imbalance in connectivity.
关键词： CNS axon regeneration,recovery of function,ipRGC,CNS trauma
更新于2025-09-23 15:21:21
-
Biomimetic Photocurable 3D Printed Nerve Guidance Channels with Aligned Cryomatrix Lumen for Peripheral Nerve Regeneration
摘要： Repair and regeneration of the critically injured peripheral nerves is one of the most challenging reconstructive surgeries. Currently available and FDA approved nerve guidance channels (NGCs) are suitable for small gap injuries, and their biological performance is inferior to that of autografts. Development of biomimetic NGCs with clinically relevant geometrical and biological characteristics such as topographical, biochemical and haptotactic cues could offer better regeneration of the long gap complex nerve injuries. Here, in this study, we present the development and preclinical analysis of a 3D printed aligned cryomatrix filled NGCs along with nerve growth factor (NGF) (aCG+NGF) for peripheral nerve regeneration. We demonstrated the application of these aCG+NGF NGCs in the enhanced and successful regeneration of a critically injured rat sciatic nerve in comparison to random cryogel filled NGCs, multichannel, and clinically preferred hollow conduits as well as gold standard autografts. Our results indicated viz-a-viz similar effect of aCG+NGF NGCs to that of autografts, and not only enhanced the overall regenerated nerve physiology, but could also mimic the cellular aspects of regeneration. This study emphasizes the paradigm that these biomimetic 3D printed NGCs will lead to a better functional regenerative outcome under clinical settings.
关键词： guidance channel,3D printing,nerve regeneration,aligned cryogel,stereolithography
更新于2025-09-23 15:21:21
-
A computational study on boron dipyromethene ancillary acceptor-based dyes for dye-sensitized solar cells
摘要： A series of (D-π)2-An-A based organic dyes containing boron dipyrromethene (BODIPY) moiety as an ancillary acceptor (An) derivative were chosen, and the effect of donor moieties (diarylamine, carbazole, azepine, and dibenzazepine) was investigated to understand their photophysical and photoelectrochemical properties by employing density functional theory (DFT) and time-dependent DFT. It is experimentally proved that BODIPY enhances the light-harvesting in red and near IR region of visible light. The electron density distribution analysis was performed for all the dyes to confirm the intramolecular charge transfer, envisioned from the simulated absorption spectra of the dyes. Carbazole donor-based dye exhibited the lowest reorganization energy. A dye attached to the TiO2 (1 0 1) surface was modeled to estimate the adsorption energy of the dyes. The density of states analysis revealed that the absence of defect states in the bandgap of TiO2 facilitates the smooth electron transfer from the excited state of the dye to the conduction band of TiO2. Considering the lowest unoccupied molecular orbital (LUMO) energy level of dyes and conduction band energy level of TiO2, it is understood that all the dyes studied in this study are capable of electron injection upon photoexcitation. Considering the driving force for dye regeneration of the dyes and the magnitude of reorganization energy, carbazole donor-based dye (D2) would be the best performing dye in DSSC. Previously, the power conversion efficiencies of the dyes have been reported, and carbazole donor-based dye (D2) exhibited the highest efficiency among all the dyes. Our computational investigations are in good agreement with the experimental results.
关键词： TiO2 (1 0 1) surface,Reorganization energy,DSSC,Dye regeneration,BODIPY
更新于2025-09-23 15:21:01
-
Laser identification of residual microislands of calculus and their removal with chelation
摘要： Background – During videoscope assisted minimally invasive surgery (VMIS) which utilizes a high magnification videoscope to treat periodontal defects, small areas resembling calculus are detected remaining on root surfaces following scaling. These are clinically termed microislands of calculus, which are removed by the use of a chelating agent. This material has not been verified as calculus and the ability of a chelating agent to remove calculus has not been proven. The purpose of this ex vivo study is to verify if the material is calculus and to determine if calculus is removed with a chelating agent. Methods – Extracted teeth (n=22) with heavy calculus on root surfaces were selected. A 5 mm2 area containing calculus was scribed on each root. Digital videoscope images were made of the marked areas using only white light and also with only a 655 nm diode laser that causes calculus to fluoresce. The marked areas were root planed until no calculus was visible with 3.5 X surgical loupes. Digital images were again made. The test area was then burnished with a chelating agent (EDTA) for 30 seconds and images again made. Utilizing the images, the percent of the marked root surface containing calculus was calculated. Results – Calculus remained on the roots surfaces after they were judged to be clean using 3.5 X loupe magnification. Remaining calculus was reduced after burnishing for 30 seconds with EDTA. Conclusions – Calculus remains on root surfaces judged to be calculus free using surgical loupes for visualization. Small areas of calculus are reduced or eliminated with a chelating agent.
关键词： regeneration,root planing,Calculus,chelation,periodontal surgery
更新于2025-09-23 15:21:01