Agreement between a new optical low coherence reflectometry biometer and an anterior segment optical coherence tomographer.

BACKGROUND: To assess agreement of measurements between a new optical low coherence reflectometry (OLCR) biometer (SW-9000, Suoer, Tianjin, China) and a spectral-domain optical coherence tomographer (SD-OCT)/Placido topographer (MS-39, CSO, Florence, Italy) in healthy subjects. METHODS: A total of 66 right eyes from 66 healthy subjects were enrolled in this prospective study. Three consecutive measurements were randomly obtained with both devices by the same experienced operator to assess agreement. Bland-Altman plots and 95% limits of agreement (LoA) were used to verify the agreement between the devices. Results are presented as mean ± standard deviation (SD). RESULTS: The SD-OCT/Placido tomographer showed high agreement with the OLCR biometer for all parameters included in this study. The mean differences of central corneal thickness (CCT), anterior chamber depth (ACD), aqueous depth (AQD), mean keratometry (Km) and corneal diameter (CD) were 2.21 ± 2.67 µm (P < 0.001), - 0.10 ± 0.03 mm (P < 0.001), - 0.10 ± 0.04 mm (P < 0.001), - 0.01 ± 0.22 D (P = 0.773) and 0.20 ± 0.16 mm (P < 0.001), respectively. This implies that the inter-device difference in Km was not statistically significant, while the differences in CCT, ACD, AQD, CD were statistically but not clinically significant. The 95% LoAs of CCT, ACD, AQD, Km and CD were - 3.01 to 7.44 µm, - 0.16 to - 0.05 mm, - 0.18 to - 0.03 mm, - 0.45 to 0.43 D, and - 0.12 to 0.51 mm, respectively. CONCLUSIONS: For CCT, ACD, AQD, Km, and CD in healthy subjects, the new OLCR biometer has high agreement with the SD-OCT/Placido tomographer and can be used interchangeably due to the narrow range of 95% LoAs.

Light-induced facile and efficient synthesis of color-variable lignin-based gold nanoparticles and its application as Pb2+ sensor.

The sustainable synthesis of gold nanoparticles (AuNPs) is widely exploited. However, the preparation of color-variable AuNPs based on renewable energy had not been reported. Here, a facile approach to synthesis color-variable lignin-based AuNPs was presented for the first time, using UV-induced decomposition of Au2O3 as the gold precursor and lignin as the stabilizer for AuNPs in dimethyl sulfoxide solvent. UV radiation technology could effectively convert Au3+ into Au0. In addition, the reaction behavior was systematically studied, and the conversion rate and reaction rate of Au2O3 could be further enhanced by changing the temperature. More interestingly, the aggregation degree of AuNPs could be adjusted by changing the amount of lignin, and the color-variable AuNPs from wine red to purple was realized. At the same time, the lignin-functionalized AuNPs showed high selectivity as the colorimetric detector towards Pb2+ ions. Our work displayed a facile, nontoxic and efficient method to prepare color-variable AuNPs, which might provide a realizable perspective to the colorimetric and sensing of AuNPs.

Effect of microstructure-scale features on lignin fluorescence for preparation of high fluorescence efficiency lignin-based nanomaterials.

As a natural fluorescent material, the practical application of lignin fluorescence was hindered due to the low fluorescence quantum yield (QY). Inspired by its aggregation fluorescence behavior, the effect of microstructure-scale on lignin fluorescence was studied from two levels, the molecular weight and colloidal sphere. It was demonstrated that with the decrease of lignin microstructure-scale, the non-radiative dissipation and reabsorption effect of lignin fluorescence would be weak, resulting in high emission efficiency. On this basis, hydrogenolysis was used to obtain small molecular fragments and reduce content of reabsorbing groups of lignin, of which the QY was greatly increased by 35 times to about 12%. In addition, the emission peak of lignin was the fluorescence addition of its main structural units. The long-wavelength emission peak was often the illusion from the reabsorption effect but not duo to the formation of conjugated structure. This work provided a potential method for the preparation of high QY lignin and an in-depth understanding of lignin fluorescence.

Insights into the effect of aggregation on lignin fluorescence and its application for microstructure analysis.

As a natural fluorescent material, the fluorescent property and mechanism of lignin were elusive until now, which hindered the high value application of lignin fluorescence. Herein, we firstly probed the previous studies on lignin fluorescence and the results indicated that lignin microstructure was an important factor for its complex fluorescence property because of fluorophore interaction and aggregation behavior. Following the rules, lignin fluorescence was explored by analyzing its aggregation fluorescence behaviors and basic fluorescence properties based on the theory of traditional conjugated luminescence and aggregation-induced emission. It was demonstrated that intermicellar aggregation of loose lignin micelle made no substantial effect on lignin fluorescence, while intramicellar aggregation could induce the enhancement of lignin fluorescence before the micellar compactness exceeded a critical value. Combined with the physicochemical structures and fluorescence properties of lignin, aggregation-induced conjugation from phenylpropane units was believed as the main sources of the visible emission of lignin and different phenylpropane aggregates consequently formed the multi-fluorophore system in lignin micelle. Furthermore, lignin aggregation fluorescence behavior has great potential in its microstructure analysis and a case study of pH/ionic strength-induced solution behavior analysis was presented. This work provided a totally new prospective for lignin fluorescence.

Lignosulfonate: A Convenient Fluorescence Resonance Energy Transfer Platform for the Construction of a Ratiometric Fluorescence pH-Sensing Probe.

Lignin is a kind of natural fluorescent polymer material. However, the application based on the fluorescent property of lignin was rarely reported. Herein, a noncovalent lignin-based fluorescence resonance energy transfer (FRET) system was readily constructed by physical blending method with spirolactam rhodamine B (SRhB) and lignosulfonate (LS) as the acceptor and donor groups, respectively. The FRET behavior, self-assembly, and energy transfer mechanism of SRhB/LS composite were systematically studied. It was demonstrated that LS could be used as a convenient aptamer as energy donor to construct water-soluble ratiometric sensors because of its inherent property of intramicelle energy transfer cascades. Our results not only present a facile and general strategy for producing lignin-based functional material but also provide a fundamental understanding about lignin fluorescence to promote the functional and high-valued applications of lignin fluorescence characteristic.

Fluorescent pH-Sensing Probe Based on Biorefinery Wood Lignosulfonate and Its Application in Human Cancer Cell Bioimaging.

A water-soluble, ratiometric fluorescent pH probe, L-SRhB, was synthesized via grafting spirolactam Rhodamine B (SRhB) to lignosulfonate (LS). As the ring-opening product of L-SRhB, FL-SRhB was also prepared. The pH-response experiment indicated that L-SRhB showed a rapid response to pH changes from 4.60 to 6.20 with a pKa of 5.35, which indicated that L-SRhB has the potential for pH detection of acidic organelle. In addition, the two probes were internalized successfully by living cells through the endocytosis pathway and could distinguish normal cells from cancer cells by different cell staining rates. In addition, L-SRhB showed obvious cytotoxicity to cancer cells, whereas it was nontoxic to normal cells in the same condition. L-SRhB might have potential in cancer therapy. L-SRhB might be a promising ratiometric fluorescent pH sensor and bioimaging dye for the recognition of cancer cells. The results also provided a new perspective to the high-value utilization of lignin.

Highly Improved Efficiency of Deep-Blue Fluorescent Polymer Light-Emitting Device Based on a Novel Hole Interface Modifier with 1,3,5-Triazine Core.

We present an investigation of deep-blue fluorescent polymer light-emitting diodes (PLEDs) with a novel functional 1,3,5-triazine core material (HQTZ) sandwiched between poly(3,4-ethylene dioxythiophene):poly(styrene sulfonic acid) layer and poly(vinylcarbazole) layer as a hole injection layer (HIL) without interface intermixing. Ultraviolet photoemission spectroscopy and Kelvin probe measurements were carried out to determine the change of anode work function influenced by the HQTZ modifier. The thin HQTZ layer can efficiently maximize the charge injection from anode to blue emitter and simultaneously enhance the hole mobility of HILs. The deep-blue device performance is remarkably improved with the maximum luminous efficiency of 4.50 cd/A enhanced by 80% and the maximum quantum efficiency of 4.93%, which is 1.8-fold higher than that of the conventional device without HQTZ layer, including a lower turn-on voltage of 3.7 V and comparable Commission Internationale de L'Eclairage coordinates of (0.16, 0.09). It is the highest efficiency ever reported to date for solution-processed deep-blue PLEDs based on the device structure of ITO/HILs/poly(9,9-dialkoxyphenyl-2,7-silafluorene)/CsF/AL. The results indicate that HQTZ based on 1,3,5-triazine core can be a promising candidate of interfacial materials for deep-blue fluorescent PLEDs.